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Projects5 Projects

ContentsArticles

R (programming language) 1SPSS 9SAS (software) 13Larsen & Toubro 25Programmable logic controller 30

ReferencesArticle Sources and Contributors 39Image Sources, Licenses and Contributors 40

Article LicensesLicense 41

R (programming language) 1

R (programming language)

R

Paradigm(s) multi-paradigm: array, object-oriented, imperative, functional, procedural, reflective

Appeared in 1993

Designed by Ross Ihaka and Robert Gentleman

Developer R Development Core Team

Stable release 3.0.2 (September 25, 2013)

Preview release Through Subversion

Typing discipline Dynamic

Influenced by S, Scheme, XLispStat

OS Cross-platform

License GNU General Public License

Website www.r-project.org [1]

• R Programming at Wikibooks

R is a free software programming language and a software environment for statistical computing and graphics. TheR language is widely used among statisticians and data miners for developing statistical software and data analysis.Polls and surveys of data miners are showing R's popularity has increased substantially in recent years.[2][3]

R is an implementation of the S programming language combined with lexical scoping semantics inspired byScheme. S was created by John Chambers while at Bell Labs. R was created by Ross Ihaka and Robert Gentleman atthe University of Auckland, New Zealand, and is currently developed by the R Development Core Team, of whichChambers is a member. R is named partly after the first names of the first two R authors and partly as a play on thename of S.R is a GNU project. The source code for the R software environment is written primarily in C, Fortran, and R. R isfreely available under the GNU General Public License, and pre-compiled binary versions are provided for variousoperating systems. R uses a command line interface; however, several graphical user interfaces are available for usewith R.

Statistical featuresR provides a wide variety of statistical and graphical techniques, including linear and nonlinear modeling, classical statistical tests, time-series analysis, classification, clustering, and others. R is easily extensible through functions and extensions, and the R community is noted for its active contributions in terms of packages. There are some important differences, but much code written for S runs unaltered. Many of R's standard functions are written in R itself, which makes it easy for users to follow the algorithmic choices made. For computationally intensive tasks, C,

R (programming language) 2

C++, and Fortran code can be linked and called at run time. Advanced users can write C, C++ or Java code tomanipulate R objects directly.R is highly extensible through the use of user-submitted packages for specific functions or specific areas of study.Due to its S heritage, R has stronger object-oriented programming facilities than most statistical computinglanguages. Extending R is also eased by its lexical scoping rules.Another strength of R is static graphics, which can produce publication-quality graphs, including mathematicalsymbols. Dynamic and interactive graphics are available through additional packages.R has its own LaTeX-like documentation format, which is used to supply comprehensive documentation, bothon-line in a number of formats and in hard copy.

Programming featuresR is an interpreted language; users typically access it through a command-line interpreter. If a user types "2+2" at theR command prompt and presses enter, the computer replies with "4", as shown below:

> 2+2

[1] 4

Like other similar languages such as APL and MATLAB, R supports matrix arithmetic. R's data structures includescalars, vectors, matrices, data frames (similar to tables in a relational database) and lists. R's extensibleobject-system includes objects for (among others): regression models, time-series and geo-spatial coordinates.R supports procedural programming with functions and, for some functions, object-oriented programming withgeneric functions. A generic function acts differently depending on the type of arguments passed to it. In otherwords, the generic function dispatches the function (method) specific to that type of object. For example, R has ageneric print() function that can print almost every type of object in R with a simple "print(objectname)" syntax.Although mostly used by statisticians and other practitioners requiring an environment for statistical computationand software development, R can also operate as a general matrix calculation toolbox – with performancebenchmarks comparable to GNU Octave or MATLAB.

Examples

Example 1The following examples illustrate the basic syntax of the language and use of the command-line interface.In R, the widely preferred assignment operator is an arrow made from two characters "<-", although "=" can be usedinstead.

> x <- c(1,2,3,4,5,6) # Create ordered collection (vector)

> y <- x^2 # Square the elements of x

> print(y) # print (vector) y

[1] 1 4 9 16 25 36

> mean(y) # Calculate average (arithmetic mean) of (vector) y; result is scalar

[1] 15.16667

> var(y) # Calculate sample variance

[1] 178.9667

> lm_1 <- lm(y ~ x) # Fit a linear regression model "y = f(x)" or "y = B0 + (B1 * x)"

# store the results as lm_1

> print(lm_1) # Print the model from the (linear model object) lm_1

R (programming language) 3

Call:

lm(formula = y ~ x)

Coefficients:

(Intercept) x

-9.333 7.000

> summary(lm_1) # Compute and print statistics for the fit

# of the (linear model object) lm_1

Call:

lm(formula = y ~ x)

Residuals:

1 2 3 4 5 6

3.3333 -0.6667 -2.6667 -2.6667 -0.6667 3.3333

Coefficients:

Estimate Std. Error t value Pr(>|t|)

(Intercept) -9.3333 2.8441 -3.282 0.030453 *

x 7.0000 0.7303 9.585 0.000662 ***

---

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 3.055 on 4 degrees of freedom

Multiple R-squared: 0.9583, Adjusted R-squared: 0.9478

F-statistic: 91.88 on 1 and 4 DF, p-value: 0.000662

> par(mfrow=c(2, 2)) # Request 2x2 plot layout

> plot(lm_1) # Diagnostic plot of regression model

R (programming language) 4

Example 2Short R code calculating Mandelbrot set through the first 20 iterations of equation z = z² + c plotted for differentcomplex constants c. This example demonstrates:•• use of community-developed external libraries (called packages), in this case caTools package• handling of complex numbers•• multidimensional arrays of numbers used as basic data type, see variables C, Z and X.

library(caTools) # external package providing write.gif function

jet.colors <- colorRampPalette(c("#00007F", "blue", "#007FFF", "cyan", "#7FFF7F",

"yellow", "#FF7F00", "red", "#7F0000"))

m <- 1200 # define size

C <- complex( real=rep(seq(-1.8,0.6, length.out=m), each=m ),

imag=rep(seq(-1.2,1.2, length.out=m), m ) )

C <- matrix(C,m,m) # reshape as square matrix of complex numbers

Z <- 0 # initialize Z to zero

X <- array(0, c(m,m,20)) # initialize output 3D array

for (k in 1:20) { # loop with 20 iterations

Z <- Z^2+C # the central difference equation

X[,,k] <- exp(-abs(Z)) # capture results

}

write.gif(X, "Mandelbrot.gif", col=jet.colors, delay=1000)

R (programming language) 5

PackagesThe capabilities of R are extended through user-created packages, which allow specialized statistical techniques,graphical devices, import/export capabilities, reporting tools, etc. These packages are developed primarily in R, andsometimes in Java, C and Fortran. A core set of packages is included with the installation of R, with 5300 additionalpackages (as of April 2012[4]) available at the Comprehensive R Archive Network (CRAN) [5], Bioconductor, andother repositories.The "Task Views" [6] page (subject list) on the CRAN website lists the wide range of applications (Finance,Genetics, Machine Learning, Medical Imaging, Social Sciences and Spatial Statistics) to which R has been appliedand for which packages are available.Other R package resources include Crantastic, a community site for rating and reviewing all CRAN packages, andalso R-Forge, a central platform for the collaborative development of R packages, R-related software, and projects. Ithosts many unpublished, beta packages, and development versions of CRAN packages.The Bioconductor project provides R packages for the analysis of genomic data, such as Affymetrix and cDNAmicroarray object-oriented data-handling and analysis tools, and has started to provide tools for analysis of data fromnext-generation high-throughput sequencing methods.Reproducible research and automated report generation can be accomplished with packages that support execution ofR code embedded within LaTeX, OpenDocument format and other markups.[7]

R (programming language) 6

Speed-up and memory efficiencyThe package jit provides JIT-compilation, and the package compiler offers a byte-code compiler for R.The packages snow, multicore, and parallel provide parallelism for R.The package ff saves memory by storing data on disk. The data structures behave as if they were in RAM. Thepackage ffbase provides basic statistical functions for 'ff'.

MilestonesThe full list of changes is maintained in the NEWS [8] file. Some highlights are listed below.• Version 0.16 – This is the last alpha version developed primarily by Ihaka and Gentleman. Much of the basic

functionality from the "White Book" (see S history) was implemented. The mailing lists commenced on April 1,1997.

• Version 0.49 – April 23, 1997 – This is the oldest available source release, and compiles on a limited number ofUnix-like platforms. CRAN is started on this date, with 3 mirrors that initially hosted 12 packages. Alpha versionsof R for Microsoft Windows and Mac OS are made available shortly after this version.

• Version 0.60 – December 5, 1997 – R becomes an official part of the GNU Project. The code is hosted andmaintained on CVS.

• Version 1.0.0 – February 29, 2000 – Considered by its developers stable enough for production use.• Version 1.4.0 – S4 methods are introduced and the first version for Mac OS X is made available soon after.• Version 2.0.0 – October 4, 2004 – Introduced lazy loading, which enables fast loading of data with minimal

expense of system memory.• Version 2.1.0 – Support for UTF-8 encoding, and the beginnings of internationalization and localization for

different languages.• Version 2.11.0 – April 22, 2010 – Support for Windows 64 bit systems.• Version 2.13.0 – April 14, 2011 – Adding a new compiler function that allows speeding up functions by

converting them to byte-code.• Version 2.14.0 – October 31, 2011 – Added mandatory namespaces for packages. Added a new parallel package.• Version 2.15.0 – March 30, 2012 – New load balancing functions. Improved serialization speed for long vectors.• Version 3.0.0 – April 3, 2013 – Support for numeric index values 231 and larger on 64 bit systems.

Interfaces

Graphical user interfaces• RGUI – comes with the pre-compiled version of R for Microsoft Windows.• Tinn-R [9]– an open source, highly capable integrated development environment featuring syntax highlighting

similar to that of MATLAB. Only available for Windows• Java Gui for R – cross-platform stand-alone R terminal and editor based on Java (also known as JGR).• Deducer [10] – GUI for menu driven data analysis (similar to SPSS/JMP/Minitab).• Rattle GUI – cross-platform GUI based on RGtk2 and specifically designed for data mining.• R Commander – cross-platform menu-driven GUI based on tcltk (several plug-ins to Rcmdr are also available).•• RapidMiner• RExcel – using R and Rcmdr from within Microsoft Excel.• RKWard – extensible GUI and IDE for R.• RStudio – cross-platform open source IDE (which can also be run on a remote linux server).• Revolution Analytics <http://www.revolutionanalytics.com/> provides a Visual Studio based IDE and has plans

for web based point and click interface.

R (programming language) 7

• Weka allows for the use of the data mining capabilities in Weka and statistical analysis in R.• AirXCell [11] provides a fully functional R Console at the bottom of their web-based AirXCell GUI.• There is a special issue of the Journal of Statistical Software (from Jun 2012) that discusses GUIs for R

<http://www.jstatsoft.org/v49>.

Editors and IDEsText editors and Integrated development environments (IDEs) with some support for R include: Bluefish,[12]

Crimson Editor, ConTEXT, Eclipse (StatET), Emacs (Emacs Speaks Statistics), LyX (modules for knitr andSweave), Vim, Geany, jEdit, Kate, R Productivity Environment (part of Revolution R Enterprise), RStudio, SublimeText, TextMate, gedit, SciTE, WinEdt (R Package RWinEdt) and Notepad++.

Scripting languagesR functionality has been made accessible from several scripting languages such as Python (by the RPy interfacepackage), Perl (by the Statistics::R[13] module), and Ruby (with the rsruby[14] rubygem). PL/R can be usedalongside, or instead of, the PL/pgSQL scripting language in the PostgreSQL and Greenplum database managementsystem. Scripting in R itself is possible via littler as well as via Rscript.

useR! conferences"useR!" is the name given to the official annual gathering of R users. The first such event was useR! 2004 in May2004, Vienna, Austria. After skipping 2005, the useR conference has been held annually, usually alternating betweenlocations in Europe and North America. Subsequent conferences were:•• useR! 2006, Vienna, Austria•• useR! 2007, Ames, Iowa, USA•• useR! 2008, Dortmund, Germany•• useR! 2009, Rennes, France•• useR! 2010, Gaithersburg, Maryland, USA•• useR! 2011, Coventry, United Kingdom•• useR! 2012, Nashville, Tennessee, USA•• useR! 2013, Albacete, Spain

Comparison with SAS, SPSS and StataThe general consensus is that R compares well with other popular statistical packages, such as SAS, SPSS and Stata.In January 2009, the New York Times ran an article about R gaining acceptance among data analysts and presenting apotential threat for the market share occupied by commercial statistical packages, such as SAS.

Commercial support for RIn 2007, Revolution Analytics was founded to provide commercial support for Revolution R, its distribution of R,which also includes components developed by the company. Major additional components include: ParallelR, the RProductivity Environment IDE, RevoScaleR (for big data analysis), RevoDeployR, web services framework, and theability for reading and writing data in the SAS file format.[15]

In October 2011, Oracle announced the Big Data Appliance, which integrates R, Apache Hadoop, Oracle Linux, anda NoSQL database with the Exadata hardware.[16][17][18] Oracle R Enterprise[19] is now one of two components ofthe "Oracle Advanced Analytics Option"[20] (the other component is Oracle Data Mining).Other major commercial software systems supporting connections to or integration with R include: JMP,Mathematica, MATLAB, Spotfire, SPSS, STATISTICA, Platform Symphony, and SAS.

R (programming language) 8

TIBCO, the current owner of the S-Plus language, is allowing some of its employees to actively support R byparticipation in its R-Help mailing list (mentioned above), and by sponsorship of the useR series of user groupmeetings. Google is a heavy user of R internally and publishes a style guide. It sponsors R projects in itsSummer-of-Code efforts, and also financially supports the useR series of meetings.RStudio offers software, education, and services to the R community.

References[1] http:/ / www. r-project. org[2] David Smith (2012); R Tops Data Mining Software Poll (http:/ / java. sys-con. com/ node/ 2288420), Java Developers Journal, May 31, 2012.[3] Karl Rexer, Heather Allen, & Paul Gearan (2011); 2011 Data Miner Survey Summary (http:/ / www. rexeranalytics. com/

Data-Miner-Survey-Results-2011. html), presented at Predictive Analytics World, Oct. 2011.[4] http:/ / en. wikipedia. org/ w/ index. php?title=R_(programming_language)& action=edit[5] http:/ / cran. r-project. org/[6] http:/ / cran. r-project. org/ web/ views/[7] CRAN Task View: Reproducible Research (http:/ / cran. r-project. org/ web/ views/ ReproducibleResearch. html)[8] http:/ / cran. r-project. org/ src/ base/ NEWS[9] http:/ / www. sciviews. org/ Tinn-R/[10] http:/ / www. deducer. org/ pmwiki/ pmwiki. php?n=Main. DeducerManual[11] http:/ / www. airxcell. com/[12] Customizable syntax highlighting based on Perl Compatible regular expressions, with subpattern support and default patterns for..R, tenth

bullet point, Bluefish Features (http:/ / bluefish. openoffice. nl/ features. html), Bluefish website, retrieved 2008-07-09.[13] Statistics::R page on [[CPAN (https:/ / metacpan. org/ module/ Statistics::R)]][14] RSRuby rubyforge project (http:/ / rubyforge. org/ projects/ rsruby/ )[15] Timothy Prickett Morgan (2011); 'Red Hat for stats' goes toe-to-toe with SAS (http:/ / www. theregister. co. uk/ 2011/ 02/ 07/

revolution_r_sas_challenge/ ), The Register, February 7, 2011.[16] Doug Henschen (2012); Oracle Makes Big Data Appliance Move With Cloudera (http:/ / www. informationweek. com/ software/

information-management/ oracle-makes-big-data-appliance-move-wit/ 232400021), InformationWeek, January 10, 2012.[17] Jaikumar Vijayan (2012); Oracle's Big Data Appliance brings focus to bundled approach (http:/ / www. computerworld. com/ s/ article/

9223325/ Oracle_s_Big_Data_Appliance_brings_focus_to_bundled_approach), ComputerWorld, January 11, 2012.[18] Timothy Prickett Morgan (2011); Oracle rolls its own NoSQL and Hadoop Oracle rolls its own NoSQL and Hadoop (http:/ / www.

theregister. co. uk/ 2011/ 10/ 03/ oracle_big_data_appliance/ ), The Register, October 3, 2011.[19] Chris Kanaracus (2012); Oracle Stakes Claim in R With Advanced Analytics Launch (http:/ / www. pcworld. com/ article/ 249509/

oracle_stakes_claim_in_r_with_advanced_analytics_launch. html), PC World, February 8, 2012.[20] Doug Henschen (2012); Oracle Stakes Claim in R With Advanced Analytics Launch (http:/ / www. informationweek. com/ software/

business-intelligence/ oracle-makes-its-big-play-for-analytics/ 232800252), InformationWeek, April 4, 2012.

External links• Official website (http:/ / www. r-project. org) of the R project• The R wiki (http:/ / rwiki. sciviews. org/ doku. php), a community wiki for R• R books (http:/ / www. r-project. org/ doc/ bib/ R-books. html), has extensive list (with brief comments) of

R-related books• R-bloggers (http:/ / www. r-bloggers. com/ ), a daily news site about R, with 10,000+ articles, tutorials and

case-studies, contributed by over 450 R bloggers.• The R Graphical Manual (http:/ / rgm3. lab. nig. ac. jp/ RGM/ ), a collection of R graphics from all R packages,

and an index to all functions in all R packages• R Graph Gallery (http:/ / gallery. r-enthusiasts. com/ ), an extensive collection of examples demonstrating the

graphing and graphical design capabilities of R, many with source code• R seek (http:/ / rseek. org), a custom frontend to Google search engine, to assist in finding results related to the R

language

SPSS 9

SPSS

IBM SPSS

Logo icon, ver. 17

SPSS v.19 x86 running on Windows 7 x86

Developer(s) IBM Corporation

Initial release 1968

Stable release 22.0 [1] August 13, 2013

Operating system Windows, zLinux, Linux / UNIX & Mac

Platform Java

Type Statistical analysis, Data Mining, Text Analytics, Data Collection, Collaboration & Deployment

License Proprietary software

Website www.ibm.com/software/analytics/spss/ [2]

SPSS Statistics is a software package used for statistical analysis. Long produced by SPSS Inc., it was acquired byIBM in 2009, and current versions are officially named IBM SPSS Statistics. Companion products in the samefamily are used for survey authoring and deployment (IBM SPSS Data Collection), data mining (IBM SPSSModeler), text analytics, and collaboration and deployment (batch and automated scoring services).

OverviewSPSS is among the most widely used programs for statistical analysis in social science. It is used by marketresearchers, health researchers, survey companies, government, education researchers, marketing organizations, andothers. The original SPSS manual (Nie, Bent & Hull, 1970) has been described as one of "sociology's mostinfluential books" for allowing ordinary researchers to do their own statistical analysis.[3] In addition to statisticalanalysis, data management (case selection, file reshaping, creating derived data) and data documentation (a metadatadictionary is stored in the datafile) are features of the base software.Statistics included in the base software:• Descriptive statistics: Cross tabulation, Frequencies, Descriptives, Explore, Descriptive Ratio Statistics• Bivariate statistics: Means, t-test, ANOVA, Correlation (bivariate, partial, distances), Nonparametric tests• Prediction for numerical outcomes: Linear regression• Prediction for identifying groups: Factor analysis, cluster analysis (two-step, K-means, hierarchical), DiscriminantThe many features of SPSS Statistics are accessible via pull-down menus or can be programmed with a proprietary 4GL command syntax language. Command syntax programming has the benefits of reproducibility, simplifying repetitive tasks, and handling complex data manipulations and analyses. Additionally, some complex applications can only be programmed in syntax and are not accessible through the menu structure. The pull-down menu interface also generates command syntax; this can be displayed in the output, although the default settings have to be changed to make the syntax visible to the user. They can also be pasted into a syntax file using the "paste" button present in each menu. Programs can be run interactively or unattended, using the supplied Production Job Facility. Additionally

SPSS 10

a "macro" language can be used to write command language subroutines, and a Python programmability extensioncan access the information in the data dictionary and data and dynamically build command syntax programs. ThePython programmability extension, introduced in SPSS 14, replaced the less functional SAX Basic "scripts" for mostpurposes, although SaxBasic remains available. In addition, the Python extension allows SPSS to run any of thestatistics in the free software package R. From version 14 onwards, SPSS can be driven externally by a Python or aVB.NET program using supplied "plug-ins".SPSS Statistics places constraints on internal file structure, data types, data processing, and matching files, whichtogether considerably simplify programming. SPSS datasets have a two-dimensional table structure, where the rowstypically represent cases (such as individuals or households) and the columns represent measurements (such as age,sex, or household income). Only two data types are defined: numeric and text (or "string"). All data processingoccurs sequentially case-by-case through the file. Files can be matched one-to-one and one-to-many, but notmany-to-many.The graphical user interface has two views which can be toggled by clicking on one of the two tabs in the bottom leftof the SPSS Statistics window. The 'Data View' shows a spreadsheet view of the cases (rows) and variables(columns). Unlike spreadsheets, the data cells can only contain numbers or text, and formulas cannot be stored inthese cells. The 'Variable View' displays the metadata dictionary where each row represents a variable and shows thevariable name, variable label, value label(s), print width, measurement type, and a variety of other characteristics.Cells in both views can be manually edited, defining the file structure and allowing data entry without usingcommand syntax. This may be sufficient for small datasets. Larger datasets such as statistical surveys are more oftencreated in data entry software, or entered during computer-assisted personal interviewing, by scanning and usingoptical character recognition and optical mark recognition software, or by direct capture from online questionnaires.These datasets are then read into SPSS.SPSS Statistics can read and write data from ASCII text files (including hierarchical files), other statistics packages,spreadsheets and databases. SPSS Statistics can read and write to external relational database tables via ODBC andSQL.Statistical output is to a proprietary file format (*.spv file, supporting pivot tables) for which, in addition to thein-package viewer, a stand-alone reader can be downloaded. The proprietary output can be exported to text orMicrosoft Word, PDF, Excel, and other formats. Alternatively, output can be captured as data (using the OMScommand), as text, tab-delimited text, PDF, XLS, HTML, XML, SPSS dataset or a variety of graphic image formats(JPEG, PNG, BMP and EMF).

The SPSS logo used prior to the renaming inJanuary 2010.

SPSS Statistics Server is a version of SPSS Statistics with aclient/server architecture. It had some features not available in thedesktop version, such as scoring functions. (Scoring functions areincluded in the desktop version from version 19.)

Versions and ownership history

Originally named Statistical Package for the Social Sciences, latermodified to Statistical Product and Service Solutions to reflect thediversity of the userbase, the software was released in its first versionin 1968 after being developed by Norman H. Nie, Dale H. Bent, and C.Hadlai Hull. Those principals incorporated as SPSS Inc. in 1975.

Early versions of SPSS Statistics were designed for batch processingon mainframes, including for example IBM and ICL versions,

SPSS 11

originally using punched cards for input. A processing run read a command file of SPSS commands and either a rawinput file of fixed format data with a single record type, or a 'getfile' of data saved by a previous run. To saveprecious computer time an 'edit' run could be done to check command syntax without analysing the data. Fromversion 10 (SPSS-X) in 1983, data files could contain multiple record types.SPSS Statistics versions 16.0 and later run under Windows, Mac, and Linux. The graphical user interface is writtenin Java. The Mac OS version is provided as a Universal binary, making it fully compatible with both PowerPC andIntel-based Mac hardware.Prior to SPSS 16.0, different versions of SPSS were available for Windows, Mac OS X and Unix. The Windowsversion was updated more frequently, and had more features, than the versions for other operating systems.SPSS Statistics version 13.0 for Mac OS X was not compatible with Intel-based Macintosh computers, due to theRosetta emulation software causing errors in calculations. SPSS Statistics 15.0 for Windows needed a downloadablehotfix to be installed in order to be compatible with Windows Vista.SPSS Inc announced on July 28, 2009 that it was being acquired by IBM for US$1.2 billion.[4] Because of a disputeabout ownership of the name "SPSS," between 2009 and 2010, the product was referred to as PASW (PredictiveAnalytics SoftWare). [5]. As of January 2010, it became "SPSS: An IBM Company". Complete transfer of businessto IBM was done by October 1, 2010. By that date, SPSS: An IBM Company ceased to exist. IBM SPSS is now fullyintegrated into the IBM Corporation, and is one of the brands under IBM Software Group's Business AnalyticsPortfolio, together with IBM Algorithmics, IBM Cognos and IBM OpenPages.

Release history•• SPSS 1 - 1968•• SPSSx release 2 - 1983•• SPSS 5.0 - December 1993•• SPSS 6.1 - February 1995•• SPSS 7.5 - January 1997•• SPSS 8.0 - 1998•• SPSS 9.0 - March 1999•• SPSS 10.0.5 - December 1999•• SPSS 10.0.7 - July 2000•• SPSS 10.1.4 - January 2002•• SPSS 11.0.1 - April 2002•• SPSS 11.5.1 - April 2003•• SPSS 12.0.1 - July 2004•• SPSS 13.0.1 - March 2005•• SPSS 14.0.1 - January 2006•• SPSS 15.0.1 - November 2006•• SPSS 16.0.1 - December 2007•• SPSS 16.0.2 - April 2008•• SPSS Statistics 17.0.1 - December 2008•• SPSS Statistics 17.0.2 - March 2009•• PASW Statistics 17.0.3 - September 2009•• PASW Statistics 18.0 - August 2009•• PASW Statistics 18.0.1 - December 2009•• PASW Statistics 18.0.2 - April 2010•• PASW Statistics 18.0.3 - September 2010•• IBM SPSS Statistics 19.0 - August 2010

SPSS 12

•• IBM SPSS Statistics 19.0.1 - December 2010•• IBM SPSS Statistics 20.0 - August 2011•• IBM SPSS Statistics 20.0.1 - March 2012•• IBM SPSS Statistics 21.0 - August 2012•• IBM SPSS Statistics 22.0 - August 2013

Notes[1] Release Notes - IBM SPSS Statistics 22 | http:/ / www-01. ibm. com/ support/ docview. wss?uid=swg27038540[2] http:/ / www. ibm. com/ software/ analytics/ spss/[3] Wellman, Barry "Doing it ourselves", Pp 71-78 in Required Reading: Sociology's Most Influential Books. Edited by Dan Clawson, University

of Massachusetts Press, 1998, ISBN 978-1-55849-153-3[4] Press release (http:/ / www. spss. com/ ibm-announce/ )[5] Ameet Sachdev, "IBM's $1.2 billion bid for SPSS Inc. helps resolve trademark dispute", Chicago Tribune, September 27, 2009, (http:/ /

articles. chicagotribune. com/ 2009-09-27/ business/ 0909250481_1_predictive-analytics-software-spss-norman-nie)

References•• Argyrous, G. Statistics for Research: With a Guide to SPSS, SAGE, London, ISBN 1-4129-1948-7• Levesque, R. SPSS Programming and Data Management: A Guide for SPSS and SAS Users, Fourth Edition

(2007), SPSS Inc., Chicago Ill. PDF (http:/ / www. spss. com/ spss/ SPSSdatamgmt_4e. pdf) ISBN1-56827-390-8

•• SPSS 15.0 Command Syntax Reference 2006, SPSS Inc., Chicago Ill.• Wellman, B. "Doing It Ourselves: The SPSS Manual as Sociology's Most Influential Recent Book."pp. 71–78 in

Required Reading: Sociology's Most Influential Books, edited by Dan Clawson. Amherst: University ofMassachusetts Press, 1998.

External links• Official website (http:/ / www. ibm. com/ software/ analytics/ spss/ )• Raynald Levesque's SPSS Tools (http:/ / www. spsstools. net) - library of worked solutions for SPSS

programmers (FAQ, command syntax; macros; scripts; python)• Archives of SPSSX-L Discussion (http:/ / listserv. uga. edu/ archives/ spssx-l. html) - SPSS Listserv active since

1996. Discusses programming, statistics and analysis• UCLA ATS Resources to help you learn SPSS (http:/ / www. ats. ucla. edu/ stat/ spss/ ) - Resources for learning

SPSS• UCLA ATS Technical Reports (http:/ / www. ats. ucla. edu/ stat/ technicalreports/ ) - Report 1 compares Stata,

SAS, and SPSS against R (R is a language and environment for statistical computing and graphics).• Using SPSS For Data Analysis (http:/ / www. hmdc. harvard. edu/ projects/ SPSS_Tutorial/ spsstut. shtml) - SPSS

Tutorial from Harvard• SPSS Community (http:/ / www. ibm. com/ developerworks/ spssdevcentral) - Support for developers of

applications using SPSS products, including materials and examples of the Python and R programmabilityfeatures

SAS (software) 13

SAS (software)

SAS

SAS 9 on Microsoft Windows

Developer(s) SAS Institute

Stable release 9.4 / July 10, 2013

Written in C

Operating system Windows, IBM mainframe, Unix/Linux, OpenVMS Alpha

Type numerical analysis

License proprietary

SAS (pronounced "sass", originally Statistical Analysis System) is an integrated system of software productsprovided by SAS Institute Inc., which enables programmers to perform:• Information retrieval and data management• Report writing and graphics• Statistical analysis, econometrics and data mining• Business planning, forecasting, and decision support• Operations research and project management•• Quality improvement• Applications development• Data warehousing (extract, transform, load)• Platform independent and remote computingIn addition, SAS has many business solutions that enable large-scale software solutions for areas such as ITmanagement, human resource management, financial management, business intelligence, customer relationshipmanagement, integrated marketing management and more.

DescriptionSAS is driven by SAS programs, which define a sequence of operations to be performed on data stored as tables.Although non-programmer graphical user interfaces to SAS exist (such as the SAS Enterprise Guide), these GUIs aremost often merely a front-end that automates or facilitates the generation of SAS programs. The functionalities ofSAS components are intended to be accessed via application programming interfaces, in the form of statements andprocedures.A SAS program has four major parts:1.1. The DATA step2.2. Procedure steps (effectively, everything that is not enclosed in a DATA step)3. A macro language, a metaprogramming language4.4. ODS (Output Delivery System) statements, which direct any output or data sets created by DATA or procedure

steps to any of various file types, and apply styles and templates to the output.SAS Library Engines and Remote Library Services allow access to data stored in external data structures and onremote computer platforms.

SAS (software) 14

The DATA-step section of a SAS program,[1] like other database-oriented fourth-generation programming languagessuch as SQL or Focus, assumes a default file structure, and by default automates the process of identifying files tothe operating system, opening the input file, reading the next record, opening the output file, writing the next record,and closing the files. This allows the user/programmer to concentrate on the details of working with the data withineach record, in effect working almost entirely within an implicit program loop that runs for each record. Any aspectof these automated functionalities may also be modified within the DATA step.All other tasks are accomplished by procedures that operate on the data set (SAS' terminology for "table") as awhole. Typical tasks include printing or performing statistical analysis, and may just require the user/programmer toidentify the data set. Procedures are not restricted to only one behavior and thus allow extensive customization,controlled by mini-languages defined within the procedures. SAS also has an extensive SQL procedure, allowingSQL programmers to use the system with little additional knowledge.There are macro programming extensions, that allow for rationalization of repetitive sections of the program. Properimperative and procedural programming constructs can be simulated by use of the "open code" macros or theInteractive Matrix Language SAS/IML component.Macro code in a SAS program, if any, undergoes preprocessing. At run time, DATA steps are compiled andprocedures are interpreted and run in the sequence they appear in the SAS program. A SAS program requires theSAS software to run.Compared to general-purpose programming languages, this structure allows the user/programmer to concentrate lesson the technical details of the data and how it is stored, and more on the information contained in the data. This blursthe line between user and programmer, appealing to individuals who fall more into the 'business' or 'research' areaand less in the 'information technology' area, since SAS does not enforce (although it recommends) a structured,centralized approach to data and infrastructure management.SAS runs on IBM mainframes, Unix, Linux, OpenVMS Alpha, and Microsoft Windows. Code is "almost"transparently moved between these environments. Older versions also have supported PC DOS, the AppleMacintosh, VMS, VM/CMS, PrimeOS, Data General AOS and OS/2.

Code exampleHello World

data _null_;

put 'Hello, world!';

run;

Compute, display and plot the ratio of confidence limits for a normal variance

data chisq;

input df;

chirat = cinv(.995,df)/cinv(.005,df);

datalines;

20

21

22

23

24

25

26

27

28

SAS (software) 15

29

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;

run;

proc print data=chisq;

var df chirat;

run;

proc plot data=chisq;

plot chirat*df;

run;

DS2 object oriented language available with Base SAS 9.4

proc ds2;

data;

dcl double min;

Retain min; keep min;

method init();

min=9999;

end;

method run();

set sasdata.class;

if weight<min then min=weight;

end;

method term();

output;

end;

run;

quit;

HistorySAS was conceived by Anthony J. Barr in 1966.[2] As a North Carolina State University graduate student from 1962to 1964, Barr had created an analysis of variance modeling language inspired by the notation of statistician MauriceKendall, followed by a multiple regression program that generated machine code for performing algebraictransformations of the raw data. Drawing on those programs and his experience with structured data files,[3] hecreated SAS, placing statistical procedures into a formatted file framework. From 1966 to 1968, Barr developed thefundamental structure and language of SAS.In January 1968, Barr and Jim Goodnight collaborated, integrating new multiple regression and analysis of varianceroutines developed by Goodnight into Barr's framework.[4][5] Goodnight's routines made the handling of basicstatistical analysis more robust, and his later implementation (in SAS 76) of the general linear model increased theanalytical power of the system.[citation needed] By 1971, SAS was gaining popularity within the academic community.One strength of the system was analyzing experiments with missing data, which was useful to the pharmaceuticaland agricultural industries, among others.In 1973, John Sall joined the project, making extensive programming contributions in econometrics, time series, and matrix algebra. Other participants in the early years included Caroll G. Perkins, Jolayne W. Service, and Jane T.

SAS (software) 16

Helwig. Perkins made programming contributions. Service and Helwig created the early documentation.In 1976, SAS Institute, Inc. was incorporated by Barr, Goodnight, Sall, and Helwig.SAS sued World Programming, the developers of a competing implementation, World Programming System,alleging that they had infringed SAS's copyright in part by implementing the same functionality. This case wasreferred from the United Kingdom's High Court of Justice to the European Court of Justice on 11 August 2010. InMay 2012, the European Court of Justice ruled in favor of World Programming, finding that "the functionality of acomputer program and the programming language cannot be protected by copyright."

VersionsSAS 71

SAS 71 represents the first limited release of the system. The first manual for SAS was printed at this time,approximately 60 pages long.[6] The DATA step was implemented. Regression and analysis of variance werethe main uses of the program.

SAS 72This more robust release was the first to achieve wide distribution. It included a substantial user's guide, 260pages in length.[7] The MERGE statement was introduced in this release, adding the ability to perform adatabase JOIN on two data sets.[8] This release also introduced the comprehensive handling of missing data.[9]

SAS 76SAS 76 was a complete system level rewrite, featuring an open architecture for adding and extendingprocedures, and for extending the compiler.[10] The INPUT and INFILE statements were significantlyenhanced to read virtually all data formats in use on the IBM mainframe.[11] Report generation was addedthrough the PUT and FILE statements.[12] The capacity to analyze general linear models was added.[13]

79.3–82.41980 saw the addition of SAS/GRAPH, a graphing component; and SAS/ETS for econometric and time-seriesanalysis. In 1981 SAS/FSP followed, providing full-screen interactive data entry, editing, browsing, retrieval,and letter writing. In 1983 full-screen spreadsheet capabilities were introduced (PROC FSCALC). For IBMmainframes, SAS 82 no longer required SAS databases to have direct access organization ( (DSORG=DAU),because SAS 82 removed location-dependent information from databases. This permitted SAS to work withdatasets on tape and other media besides disk.

Version 4 seriesIn the early 1980s, SAS Institute released Version 4, the first version for non-IBM computers. It was writtenmostly in a subset of the PL/I language, to run on several minicomputer manufacturers' operating systems andhardware: Data General's AOS/VS, Digital Equipment's VAX/VMS, and Prime Computer's PRIMOS. Theversion was colloquially called "Portable SAS" because most of the code was portable, i.e., the same codewould run under different operating systems.

Version 6 seriesVersion 6 represented a major milestone for SAS. While it appeared superficially similar to the user, major changes occurred "under the hood": the software was rewritten. From its FORTRAN origins, followed by PL/I and mainframe assembly language; in version 6 SAS was rewritten in C, to provide enhanced portability between operating systems, as well as access to an increasing pool of C programmers compared to the shrinking pool of PL/I programmers. This was the first version to run on UNIX, MS-DOS and Windows platforms. The DOS versions were incomplete implementations of the Version 6 spec: some functions and formats were unavailable, as were SQL and related items such as indexing and WHERE subsetting. DOS memory limitations restricted the size of some user-defined items. The mainframe version of SAS 6 changed

SAS (software) 17

the physical format of SAS databases from "direct files" (DSORG=DA) to standard blocked physicalsequential files (DSORG=PS,RECFM=FS) with a customized EXCP macro instead of BSAM, QSAM orpreviously BDAM which was used through version 5 until the complete rewrite of version 6. The practicalbenefit of this change is that a SAS 6 database can be copied from any media with any copying tool includingIEBGENER — which uses BSAM. In 1984 a project management component was added (SAS/PROJECT). In1985 SAS/AF software, econometrics and time series analysis (SAS/ETS) component, and interactive matrixprogramming (SAS/IML) software was introduced. MS-DOS SAS (version 6.02) was introduced, along with alink to mainframe SAS. In 1986 Statistical quality improvement component is added (SAS/QC software);SAS/IML and SAS/STAT software is released for personal computers. 1987 saw concurrent update accessprovided for SAS data sets with SAS/SHARE software. Database interfaces are introduced for DB2 andSQL-DS. In 1988 SAS introduced the concept of MultiVendor Architecture (MVA); SAS/ACCESS softwareis released. Support for UNIX-based hardware announced. SAS/ASSIST software for building user-friendlyfront-end menus is introduced. New SAS/CPE software establishes SAS as innovator in computerperformance evaluation. Version 6.03 for MS-DOS is released. 6.06 for MVS, CMS, and OpenVMS isannounced in 1990. The same year, the last MS-DOS version (6.04) is released. Data visualization capabilitiesadded in 1991 with SAS/INSIGHT software. In 1992 SAS/CALC, SAS/TOOLKIT, SAS/PH-Clinical, andSAS/LAB software is released. In 1993 software for building customized executive information systems (EIS)is introduced. Release 6.08 for MVS, CMS, VMS, VSE, OS/2, and Windows is announced. 1994 saw theaddition of ODBC support, plus SAS/SPECTRAVIEW and SAS/SHARE*NET components. 6.09 saw theaddition of a data step debugger. 6.09E for MVS. 6.10 in 1995 was a Microsoft Windows release and the firstrelease for the Apple Macintosh. Version 6 was the first, and last series to run on the Macintosh. JMP, alsoproduced by the SAS Institute, is the software package the company produces for the Macintosh. Also in 1995,6.11 (codenamed Orlando) was released for Windows 95, Windows NT, and UNIX. In 1996 SAS announcesWeb enablement of SAS software and introduced the scalable performance data server. In 1997SAS/Warehouse Administrator and SAS/IntrNet software goes into production. 1998 sees SAS introduce acustomer relationship management (CRM) solution, and an ERP access interface — SAS/ACCESS interfacefor SAP R/3. SAS is also the first to release OLE-DB for OLAP and releases HOLAP solution. Balancedscorecard, SAS/Enterprise Reporter, and HR Vision are released. First release of SAS Enterprise Miner. 1999sees the releases of HR Vision software, the first end-to-end decision-support system for human resourcesreporting and analysis; and Risk Dimensions software, an end-to-end risk-management solution. MS-DOSversions are abandoned because of Y2K issues and lack of continued demand. In 2000 SAS shipped EnterpriseGuide and ported its software to Linux.

Version 7 seriesThe Output Delivery System debuted in version 7; as did long variable names (from 8 to 32 characters);storage of long character strings in variables (from 200 to 32,767); and a much improved built-in text editor,the Enhanced Editor. Version 7 saw the synchronisation of features between the various platforms for aparticular version number (which previously hadn't been the case). Version 7 foreshadowed version 8. It wasbelieved in the SAS users community, although never officially confirmed, that in releasing version 7 SASInstitute released a snapshot from their development on version 8 to meet a deadline promise. To some, SASInstitute recommending that sites wait until version 8 before deploying the new software was a confirmation ofthis.

Version 8 seriesReleased about 1999; 8.0, 8.1, 8.2 were Unix, Linux, Microsoft Windows, CMS (z/VM) and z/OS releases.Key features: long variable names, Output Delivery System (ODS). SAS 8.1 was released in 2000. SAS 8.2was released in 2001.

Version 9 series

SAS (software) 18

Version 9 makes additions to base SAS. The new hash object now allows functionality similar to the MERGEstatement without sorting data or building formats. The function library was enlarged, and many functionshave new parameters. Perl Regular Expressions are now supported, as opposed to the old "RegularExpression" facility, which was incompatible with most other implementations of Regular Expressions. Longformat names are now supported. SAS 9.2 released in March 2008 and was demonstrated at SAS GlobalForum (previously called SUGI) 2008.[14] The new features are listed in the "What's New in SAS" webpage.[15] SAS 9.2 was released incrementally in three phases:[16]

1.1. MVA-based products e.g. SAS/BASE, SAS/STAT, SAS/Graph. Nothing that relies on metadata. Limitedavailability from March 2008 because most users rely on the Metadata Server (see Phase 2) or products releasedin Phase 3.

2.2. Enterprise Intelligence Platform. Metadata Server for Business Intelligence (BI) and Data Integration.Availability from March 2009.

3. Client software for metadata driven analytics and business solutions. Enterprise Miner, Text Miner, Modelmanager. Solutions include Financial, Retail, Health & Life Science. Probably released in 2nd Quarter 2009.

SAS 9.3 was released July 2011 and was followed by a service release in December 2011.[17]

SAS 9.4 was released July 2013.[18]

Market shareSAS is the largest market-share holder in advanced analytics with 36.2 percent of the market as of 2012. It is the fifthlargest market-share holder for BI software with a 6.9% share and the largest independent vendor. It competes in theBI market against conglomerates, such as SAP BusinessObjects, IBM Cognos, SPSS Modeler, Oracle Hyperion, andMicrosoft BI. SAS has been named in the Gartner Leader's Quadrant for Data Integration Tools and for BusinessIntelligence and Analytical Platforms. SAS was given the strongest position out of all the vendors evaluated in theForrester Wave for Big Data Predictive Analytics Solutions.

ComponentsSAS consists of a number of components which organizations separately license and install as required.Base SAS

The core of SAS, Base SAS Software, manages data and calls procedures. SAS procedures softwareanalyzes and reports the data. The SQL procedure allows SQL (Structured Query Language) programming inlieu of data step and procedure programming. Library Engines allow transparent access to common datastructures such as Oracle, as well as pass-through of SQL to be executed by such data structures. The Macrofacility is a tool for extending and customizing SAS software programs and reducing overall programverbosity. The DATA step debugger is a programming tool that helps find logic problems in DATA stepprograms. The Output Delivery System (ODS) is an extendable system that delivers output in a variety offormats, such as SAS data sets, listing files, RTF, PDF, XML, or HTML. The SAS windowing environmentis an interactive, graphical user interface used to run and test SAS programs.

BI DashboardA plugin for Information Delivery Portal. It allows the user to create various graphics that represent a broadrange of data. This allows a quick glance to provide a lot of information, without having to look at all theunderlying data.

Data Integration StudioProvides extract, transform, load (ETL) services.

SAS Enterprise Business Intelligence Server

SAS (software) 19

Includes both a suite of business intelligence (BI) tools and a platform to provide uniform access to data. Thegoal of this product is to compete with Business Objects and Cognos' offerings.

Enterprise Computing Offer (ECO)Not to be confused with Enterprise Guide or Enterprise Miner, ECO is a product bundle.

Enterprise GuideSAS Enterprise Guide is a Microsoft Windows client application that provides a guided mechanism to useSAS and publish dynamic results throughout an organization in a uniform way. It is marketed as the defaultinterface to SAS for business analysts, statisticians, and programmers. Though Data Integration Studio is thetrue ETL tool of SAS, Enterprise Guide can be used for the ETL of smaller projects.

Enterprise MinerA data mining tool.

Information Delivery PortalAllows users to set up personalized homepages where they can view automatically generated reports,dashboards, and other SAS data structures.

Information Map StudioA client application that helps with building information maps.

OLAP Cube StudioA client application that helps with building OLAP Cubes.

SAS Web OLAP Viewer for JavaWeb based application for viewing OLAP cubes and data explorations. (Discontinued as per Nov 2010 )

SAS Web OLAP Viewer for.NETSAS/ACCESS

Provides the ability for SAS to transparently share data with non-native datasources.SAS/ACCESS for PC Files

Allows SAS to transparently share data with personal computer applications including MS Access andMicrosoft Office Excel.

SAS Add-In for Microsoft OfficeA component of the SAS Enterprise Business Intelligence Server, is designed to provide access to data,analysis, reporting and analytics for non-technical workers (such as business analysts, power users, domainexperts and decision makers) via menus and toolbars integrated into Office applications.

SAS/AFApplications facility, a set of application development tools to create customized desktop GUI applications; alibrary of drag-and-drop widgets are available; widgets and models are fully object oriented; SCL programscan be attached as needed.

SAS/SCLSAS Component Language, allows programmers to create and compile object-oriented programs. Uniquely,SAS allows objects to submit and execute Base/SAS and SAS/Macro statements.

SAS/ASSISTEarly point-and-click interface to SAS, has since been superseded by SAS Enterprise Guide and itsclient–server architecture.

SAS/C

SAS (software) 20

SAS/CALCIs a discontinued spreadsheet application, which came out in version 6 for mainframes and PCs, and didn'tmake it further.

SAS/CONNECTProvides ability for SAS sessions on different platforms to communicate with each other.

SAS/DMIA programming interface between interactive SAS and ISPF/PDF applications. Obsolete since version 5.

SAS/EISA menu-driven system for developing, running, and maintaining an enterprise information systems.

SAS/ETSProvides Econometrics and Time Series Analysis

SAS/FSPAllows interaction with data using integrated tools for data entry, computation, query, editing, validation,display, and retrieval.

SAS/GISAn interactive desktop Geographic Information System for mapping applications.

SAS/GRAPHAlthough base SAS includes primitive graphing capabilities, SAS/GRAPH is needed for charting on graphicalmedia.

SAS/IMLMatrix-handling SAS script extensions.

SAS/INSIGHTDynamic tool for data mining — allows examination of univariate distributions, visualization of multivariatedata, and model fitting using regression, analysis of variance, and the generalized linear model.

SAS/Integration TechnologiesAllows the SAS System to use standard protocols, like LDAP for directory access, CORBA and Microsoft'sCOM/DCOM for inter-application communication, as well as message-oriented middleware like MicrosoftMessage Queuing and IBM WebSphere MQ. Also includes the SAS' proprietary client–server protocols usedby all SAS clients.

SAS/IntrNetExtends SAS’ data retrieval and analysis functionality to the Web with a suite of CGI and Java tools

SAS/LABSuperseded by SAS Enterprise Guide.

SAS/OROperations Research

SAS/PH-ClinicalDefunct product

SAS/QCQuality Control provides quality improvement tools.

SAS/SHAREA data server that allows multiple users to gain simultaneous access to SAS files

SAS (software) 21

SAS/SHARE*NETDiscontinued and now part of SAS/SHARE. It allowed a SAS/SHARE data server to be accessed from non-sasclients, like JDBC or ODBC compliant applications.

SAS/SPECTRAVIEWAllows visual exploration of large amounts of data. Once the system has plotted the data in a 3D space, userscan then visualise it by creating envelope surfaces, cutting planes, etc., which can be animated depending on afourth parameter (time for example).

SAS/STATStatistical Analysis with a number of procedures, providing statistical information such as analysis of variance,regression, multivariate analysis, and categorical data analysis. Note for example the GLIMMIX procedure.

SAS/TOOLKITSAS/Warehouse Administrator

superseded in SAS 9 by SAS ETL Server.SAS Web Report Studio

Part of the SAS Enterprise Business Intelligence Server, provides access to query and reporting capabilities onthe Web. Aimed at non-technical users.

SAS Financial ManagementBudgeting, planning, financial reporting and consolidation.

SAS Activity Based ManagementCost and revenue modeling.

SAS Strategy Management (formerly Strategic Performance Management)Collaborative scorecards.

SAS Scalable Performance Data Server (SPDS)Distributed data system offering increased performance; Data processing server.

SAS Visual AnalyticsVisualisations for large scale data solutions. [19]

SAS Grid ManagerGrid computing capabilities, enabling organizations to create a managed, shared environment for processinglarge volumes of data and analytic programs. [20]

TerminologyWhere many other languages refer to tables, rows, and columns/fields, SAS uses the terms data sets, observations,and variables (although in some of the GUI applications, it is not consistent with these terms, sometimes referring tocolumns and rows). There are only two kinds of variables in SAS: numeric and character (string). By default allnumeric variables are stored as (8 byte) real. It is possible to reduce precision in external storage only. Date anddatetime variables are numeric variables that inherit the C tradition and are stored as either the number of days (fordate variables) or seconds (for datetime variables).

SAS (software) 22

FeaturesThis list is incomplete; you can help by expanding it [21].

•• Read and write different file formats.•• Process data in different formats.• SAS programming language, a 4th generation programming language. SAS DATA steps are written in a

3rd-generation procedural language very similar to PL/I; SAS PROCS, especially PROC SQL, are non-proceduraland therefore better fit the definition of a 4GL.

•• WHERE filtering available in DATA steps and PROCs; based on SQL WHERE clauses, incl. operators like LIKEand BETWEEN/AND.

•• Built-in statistical and random number functions.• Functions for manipulating character and numeric variables. Version 9 includes Perl Regular Expression

processing.•• System of formats and informats. These control representation and categorization of data and may be used within

DATA step programs in a wide variety of ways. Users can create custom formats, either by direct specification orvia an input dataset.

•• Comprehensive date- and time-handling functions; a variety of formats to represent date and time informationwithout transformation of underlying values.

• Interaction with database products through a subset of SQL (and ability to use SQL internally to manipulate SASdata sets). Almost all SAS functions and operators available in PROC SQL.

•• SAS/ACCESS modules allow communication with databases (including databases accessible via ODBC); in mostcases, database tables can be viewed as though they were native SAS data sets. As a result, applications maycombine data from many platforms without the end-user needing to know details of or distinctions between datasources.

• Direct output of reports to CSV, HTML, PCL, PDF, PostScript, RTF, XML, and more using Output DeliverySystem. Templates, custom tagsets, styles incl. CSS and other markup tools available and fully programmable.

• Interaction with the operating system (for example, pipelining on Unix and Windows and DDE on Windows).•• Fast development time, particularly from the many built-in procedures, functions, in/formats, the macro facility,

etc.• An integrated development environment.•• Dynamic data-driven code generation using the SAS Macro language.•• Can process files containing millions of rows and thousands of columns of data.•• University research centers often offer SAS code for advanced statistical techniques, especially in fields such as

Political Science, Economics and Business Administration.• Large user community supported by SAS Institute. Users have a say in future development, e.g. via the annual

SASWare Ballot.[22]

Competitors•• DAP•• GenStat•• Angoss•• Mathematica•• Matlab•• R•• SPSS•• SPSS Modeler•• Stata

SAS (software) 23

•• STATISTICA•• WPS•• AleaSoft

Notes[1] "EWHC 1829 - British and Irish Legal Information Institute" (http:/ / www. bailii. org/ ew/ cases/ EWHC/ Ch/ 2010/ 1829. html#para36),

Bailii.org, 2010.[2] Greenberg & Cox, et al. 1978:181. Reference to the creation of SAS by Barr in 1966.[3] Barr contributed to the development of the NIPS Formatted File System while working for IBM at the Pentagon from 1964 to 1966. FFS was

one of the first data management systems to take advantage of files with a defined structure for efficiencies in data storage and retrieval.[4] (Barr & Goodnight, et al. 1976:"The SAS Staff") Attribution of contributions to SAS 72 and SAS 76 to Barr, Goodnight, Service, Perkins,

and Helwig.[5] (Barr & Goodnight et al. 1979:front matter) Attribution of the development of various parts of the system to Barr, Goodnight, and Sall.[6] (Barr & Goodnight 1971)[7][7] (Service 1972)[8] (Service 1972:47–49)[9][9] (Service 1972:28,65,67,etc.)[10] (Barr & Goodnight, et al. 1979) This programmer's guide facilitated the extension of SAS through its open interface.[11] (Barr & Goodnight, et al. 1976:11–15)[12] (Barr & Goodnight, et al. 1976:38–44)[13] (Barr & Goodnight, et al. 1976:127–144)[14] http:/ / support. sas. com/ events/ sasglobalforum/ 2008/ index. html[15] http:/ / support. sas. com/ documentation/ whatsnew/ index. html[16] http:/ / www. sas. com/ offices/ asiapacific/ sp/ usergroups/ snug/ archive/ 2008/ presentations/ LaiPhongTranApril08. pdf[17] http:/ / support. sas. com/ software/[18] What's new in SAS 9.4 http:/ / support. sas. com/ documentation/ cdl/ en/ whatsnew/ 64788/ HTML/ default/ titlepage. htm[19] http:/ / support. sas. com/ software/ products/ va/ index. html[20] http:/ / www. sas. com/ technologies/ architecture/ grid/ index. html[21] http:/ / en. wikipedia. org/ w/ index. php?title=SAS_(software)& action=edit[22] http:/ / www. sascommunity. org/ wiki/ Main_Page

References• SAS Company History (http:/ / www. sas. com/ presscenter/ bgndr_history. html)• Barr, Anthony J., Goodnight, James H. SAS, Statistical Analysis System, Student Supply Store, North Carolina

State University, 1971. OCLC 5728643 (http:/ / www. worldcatlibraries. org/ oclc/ 5728643)• Barr, Anthony J., Goodnight, James H., Sall, John P., Helwig, Jane T. A User's Guide to SAS 76, SAS Institute,

Inc., 1976. ISBN 0-917382-01-3• Barr, Anthony J., Goodnight, James H., Sall, John P., Helwig, Jane T. SAS Programmer's Guide, 1979 Edition,

SAS Institute, Inc., 1979. OCLC 4984363 (http:/ / www. worldcatlibraries. org/ oclc/ 4984363)•• Cody, Ron and Ray Pass. SAS Programming by Example. 1995. SAS Institute.• Delwiche, Lora D. and Susan J. Slaughter. The Little SAS Book (http:/ / support. sas. com/ publishing/ authors/

slaughter. html). 2008. SAS Institute.• Slaughter, Susan J. and Lora D. Delwiche. The Little SAS Book for Enterprise Guide 4.2 (http:/ / support. sas.

com/ publishing/ authors/ slaughter. html). 2010. SAS Institute.• McDaniel, Stephen and Hemedinger, Chris. SAS for Dummies. (http:/ / support. sas. com/ sasfordummies) 2007.

Wiley.• Greenberg, Bernard G.; Cox, Gertrude M.; Mason, David D.; Grizzle, James E.; Johnson, Norman L.; Jones, Lyle

V.; Monroe, John; Simmons, Gordon D., Jr. (1978), "Statistical Training and Research: The University of NorthCarolina System" (http:/ / links. jstor. org/ sici?sici=0306-7734(197808)46:2<171:STARTU>2. 0. CO;2-S), inNourse, E. Shepley, International Statistical Review 46: 171–207

SAS (software) 24

• Service, Jolayne A User's Guide to the Statistical Analysis System., Student Supply Stores, North Carolina StateUniversity, 1972. OCLC 1325510 (http:/ / www. worldcatlibraries. org/ oclc/ 1325510)

External links• SAS homepage (http:/ / www. sas. com)• sasCommunity.org is the Wiki for all things SAS (http:/ / www. sascommunity. org/ wiki/ Main_Page)• Find the Sasopedia under sasCommunity.org (http:/ / www. sascommunity. org/ wiki/ Sasopedia)•• Wikiversity:Data Analysis using the SAS Language• SAS tips and techniques (http:/ / www. amadeus. co. uk/ sas-technical-services/ tips-and-techniques/ )

Larsen & Toubro 25

Larsen & ToubroCoordinates: 18°56′06.07″N 72°50′30.00″E [1]

Larsen & Toubro Ltd.

Type Public

Traded as NSE: LT [2]

BSE: 500510 [3]

BSE SENSEX Constituent

Industry Conglomerate

Founded Mumbai, India (1938)

Founder(s) Henning Holck LarsenSøren Kristian Toubro

Headquarters L&T House, Ballard Estate,Mumbai, Maharashtra, India

Area served India, Middle East, East Asia and South East Asia

Key people K. Venkataramanan (CEO & MD)A. M. Naik(Executive Chairman))

Products ConstructionHeavy equipmentElectrical equipmentPowerShipbuildingFinancial servicesIT Services

Revenue US$ 14 billion (2012)

Operating income US$ 1.488 billion (2012)

Net income US$ 907 million (2012)

Total assets US$ 22.84 billion (2012)

Total equity US$ 5.978 billion (2012)

Employees 45,117 (2012)

Divisions Technology, engineering, construction, manufacturing

Subsidiaries L&T MHI, L&T Infotech, L & T Mutual Fund, L&T Infrastructure Finance Company, L&T Finance Holdings, L&T IES

Website www.larsentoubro.com [4]

Larsen & Toubro Limited, also known as L&T, is an Indian multinational conglomerate headquartered inMumbai, India.[5] The company has business interests in engineering, construction, manufacturing goods,information technology and financial services.L&T is India's largest engineering and construction company,Considered to be the "bellwether of India's engineering sector", L&T was recognized as the Company of the Year in2010.

Larsen & Toubro 26

HistoryA company was founded in Mumbai in 1938 by two Danish engineers, Henning Holck-Larsen and Soren KristianToubro. The company began as a representative of Danish manufacturers of dairy equipment. However, with thestart of the Second World War in 1939 and the resulting restriction on imports, the partners started a small workshopto undertake jobs and provide service facilities.[citation needed]

Germany's invasion of Denmark in 1940 stopped supplies of Danish products. The war-time need to repair and refitships offered L&T an opportunity, and led to the formation of a new company, Hilda Ltd., to handle theseoperations. L&T also started to repair and fabrication shops signalling the expansion of the company.[citation needed]

The sudden internment of German engineers in India (due to suspicions caused by the War), who were to put up asoda ash plant for the Tatas, gave L&T a chance to enter the field of installation.[citation needed]

In 1944, ECC was incorporated by the partners; the company at this time was focused on construction projects(Presently, ECC is the construction division of L&T). L&T decided to build a portfolio of foreign collaborations. By1945, the company represented British manufacturers of equipment used to manufacture products such ashydrogenated oils, biscuits, soaps and glass.[citation needed]

In 1945, the company signed an agreement with Caterpillar Tractor Company, USA, for marketing earth movingequipment. At the end of the war, large numbers of war-surplus Caterpillar equipment were available at attractiveprices, but the finances required were beyond the capacity of the partners. This prompted them to raise additionalequity capital, and on 7 February 1946, Larsen & Toubro Private Limited was born.[citation needed]

Post IndependenceOffices were set up in Kolkata (Calcutta), Chennai (Madras) and New Delhi. In 1948, fifty-five acres of undevelopedmarsh and jungle was acquired in Powai, Mumbai. That uninhabitable swamp subsequently became the site of itsmain manufacturing hub.[citation needed]

In December 1950, L&T became a public company with a paid-up capital of Rs. 20 lakhs (2 millionrupees)(20,00,000.00). The sales turnover in that year was Rs. 1.09 crore (10.9 million rupees). In 1956, a major partof the company's Mumbai office moved to ICI House in Ballard Estate, Mumbai; which would later be purchased bythe company and renamed as L&T House, its present corporate office.[citation needed]

The sixties witnessed the formation of many new ventures: UTMAL (set up in 1960), Audco India Limited (1961),Eutectic Welding Alloys (1962) and TENGL (1963).[citation needed]

Operating DivisionsL&T has delivered Engineering and Construction (EPIC) services for many projects in the upstream hydrocarbonsector over the last two decades, in India, Middle East, Africa, South-East Asia and Australia.L&T has formed a joint venture with SapuraCrest Petroleum Berhad, Malaysia for providing services to offshoreconstruction industry worldwide. The joint venture will own and operate the LTS 3000, a Heavy Lift cum PipelayVessel. L&T has more than 38000 employees in India.L&T Power has set up an organization focused on coal-based, gas-based and nuclear power projects. L&T hasformed two joint ventures with Mitsubishi Heavy Industries, Japan to manufacture super critical boilers and steamturbine generators.L&T is among the top five fabrication companies in the world. L&T has a shipyard capable of constructing vesselsof up to 150 meters long and displacement of 20,000 tons at its heavy engineering complex at Hazira. The shipyardis geared up to take up construction of niche vessels such as specialized Heavy lift Cargo Vessels, CNG carriers,Chemical tankers, defense & para military vessels, submarines and other role specific vessels.

Larsen & Toubro 27

The design wing of L&T ECC is called EDRC (Engineering Design and Research Centre). EDRC providesconsultancy, design and total engineering solutions to customers. It carries out basic and detailed design for bothresidential and commercial projects.

L&T SolarL&T Construction a subsidiary of the Larsen & Toubro conglomerate also undertakes solar projects. In April ’12,L&T commissioned India's largest solar photo voltaic-based power plant (40 MWp) owned by Reliance Power atJaisalmer, Rajasthan from concept to commissioning in 129 days. In 2011, L&T entered into a partnership withSharp for EPC (engineering, procurement and construction) in megawatt solar project and plan to construct about100 MW in the next 12 months in most of the metros. L&T Infra Finance, promoted by the parent L&T Ltd, is alsoactive in the funding of solar projects in India.

Electrical and electronicsL&T is an international manufacturer of a wide range of electrical and electronic products and systems. L&T alsomanufactures custom-engineered switchboards for industrial sectors like power, refineries, petrochemicals andcement. In the electronic segment, L&T offers a range of meters and provides control and automation systems forindustries. Medical Equipment.

Information technologyL&T Infotech focuses on information technology and software services. Larsen & Toubro Infotech Limited, a 100per cent subsidiary of the L&T, offers software and services with a focus on Manufacturing, BFSI andCommunications and Embedded Systems. It also provides services in the embedded intelligence and engineeringspace.

L&T Machinery & Industrial ProductsL&T manufactures, markets and provides service support for construction and mining machinery, surface miners,hydraulic excavators, aggregate crushers, loader backhoes and vibratory compactors; supplies a wide range of rubberprocessing machinery; and manufactures and markets industrial valves and allied products and a range ofapplication-engineered welding alloys.[citation needed]

L&T EWACEWAC Alloys Limited, started as a joint venture of Larsen & Toubro Limited, India & Messer Eutectic CastolinGroup, Germany. Prof. Wasserman, Founder of Eutectic Castolin, and Mr.Henning Hock Larsen, Founder of Larsen& Toubro, laid the foundation of Eutectic Division in India in the year 1962. More than 100 years, the Eutectic hasbeen offering state-of-the-art solutions to conserve metallic resources. In the year 2011, EWAC Alloys Limitedbecame a wholly owned subsidiary of Larsen & Toubro Limited.

Larsen & Toubro 28

Subsidiaries & Joint Ventures

L&T – Komatsu LimitedHaving its registered office at Mumbai, India and focusing on construction equipment and mining equipment,L&T-Komatsu Limited is a joint venture of Larsen and Toubro, and Komatsu Asia Pacific Pte Limited, Singapore, awholly owned subsidiary of Komatsu Limited, Japan. Komatsu is the world’s second largest manufacturer ofhydraulic excavators and has manufacturing and marketing facilities.The plant was started in the year 1975 by L&T to manufacture Hydraulic Excavators for the first time in India. In1998, it became a joint venture. L&T–Komatsu Limited’s manufacturing facility—The BangaloreWorks—comprises Machinery Works and Hydraulics Works. Machinery Works has a modern manufacturing facilitywith ISO 9001:2008 accreditation for design, manufacture and servicing of earthmoving equipment. HydraulicsWorks, with a precision machine shop, manufactures the complete range of high pressure hydraulic components andsystems, and is ISO 9001:2008 certified for design, development, manufacturing and servicing of hydraulic pumps,motors, cylinders, turning joints, hose assemblies, valve blocks, hydraulic systems and power drives as well as alliedgear boxes.

L&T FinanceLarsen & Toubro financial services Financial Services is a subsidiary which was incorporated as a Non BankingFinance company in November 1994.The subsidiary has a spectrum of financial products and services for corporate, construction equipments etc. L&TFinance was able to withstand the market dynamics and adapt as per that. This is a new division after the companydeclared its restructuringL & T Mutual Fund is the mutual fund company of the L&T group. This company provides mutual fund schemes forinvestors in India.

Larsen & Toubro Infrastructure FinanceLarsen and Toubro Infrastructure Finance Company Limited was set up as a 100% subsidiary of L&T. It commencedits business in January 2007 upon obtaining Non-Banking Financial Company (NBFC) license from the ReserveBank of India (RBI).As of 31 March 2008, L&T Infrastructure Finance has approved financing of more than a billion USD to selectprojects in the infrastructure sector.L&T Infrastructure Finance has received the status of "Infrastructure Finance Company" from the Reserve Bank ofIndia within the overall classification of "Non-Banking Financial Company".

L&T (TS)L&T Technology Services (previously known as Integrated Engineering Services or L&T IES), a business unit ofL&T, offers a combination of mechanical, electrical and electronic design (mechatronics/embedded systems), civiland architectural services. L&T TS has its design and delivery locations in Vadodara, Chennai, Bangalore, Mysoreand Mumbai in India.L&T TS services also encompass architectural, civil, structural design and building utility systems design. Practicesinclude both product and plant engineering services in the automotive, trucks and off-highway vehicles, industrial .Mysore based campus of Electronic design unit of TS works predominantly for Embedded systems with a variety ofrange of operations from Avionics, Automotive, Industrial automation and metering, Medical and more.

Larsen & Toubro 29

L&T ValvesL&T’s Valves Business Group markets valves manufactured by L&T's Valve Manufacturing Unit and L&T's jointventures, Audco India Limited, India and Larsen & Toubro Valves Manufacturing Unit, Coimbatore as well as alliedproducts from major international manufacturers.The company's valve manufacturing Unit in Coimbatore manufactures industrial valves specifically for the PowerIndustry. It also sells value-added flow control solutions to oil and gas, refining, petrochemical, chemical and powerindustries, industrial valves and customized products for major Refinery, LNG, GTL, Petrochemical and Powerprojects.L&T Valves Business Group has offices in the USA, South Africa, Dubai, Abu Dhabi, India and China, andalliances with valve distributors and agents in these countries.

Corporate structureIn January 2011, Mr. A.M. Naik announced that the company will be restructured into nine virtual companies. Eachwill be called an independent company, and will have a CEO, CFO and HR head, its own profit and loss account,and a board of directors with at least three independent directors. Each board will not have any legal or statutorystanding, but will merely advise management.The nine virtual companies will operate in different segments, The nine sectors for which companies are formed are:1.1. Building and Factories2.2. Civil Infrastructure3.3. Mechanical-Metal Handling and Supply of Equipment for steel industry4.4. Electric Power transmission and distribution5.5. Hydrocarbon and Chemicals6.6. Heavy Engineering Catering to defense and Aerospace7.7. Electrical Equipment and Automation Products8.8. Mechanical and Industrial Products9.9. Power Equipment and building Power Plants

References[1] http:/ / tools. wmflabs. org/ geohack/ geohack. php?pagename=Larsen_%26_Toubro& params=18_56_06. 07_N_72_50_30.

00_E_region:US_dim:540[2] http:/ / www. nseindia. com/ marketinfo/ companyinfo/ companysearch. jsp?cons=LT& section=7[3] http:/ / www. bseindia. com/ bseplus/ StockReach/ AdvanceStockReach. aspx?scripcode=500510[4] http:/ / www. larsentoubro. com/[5] Larsen & Toubro Ltd 171109.pdf (http:/ / www. bseindia. com/ xml-data/ corpfiling/ AttachHis/ Larsen_& _Toubro_Ltd_171109. pdf)

External links• Official website (http:/ / www. larsentoubro. com)

Programmable logic controller 30

Programmable logic controller

Siemens Simatic S7-400 system at rack,left-to-right: power supply unit PS407 4A,CPU

416-3, interface module IM 460-0 andcommunication processor CP 443-1.

A Programmable Logic Controller, PLC or ProgrammableController is a digital computer used for automation ofelectromechanical processes, such as control of machinery on factoryassembly lines, amusement rides, or light fixtures. The abbreviation"PLC" and the term "Programmable Logic Controller" are registeredtrademarks of the Allen-Bradley Company (Rockwell Automation).PLCs are used in many industries and machines. Unlikegeneral-purpose computers, the PLC is designed for multiple inputsand output arrangements, extended temperature ranges, immunity toelectrical noise, and resistance to vibration and impact. Programs tocontrol machine operation are typically stored in battery-backed-up ornon-volatile memory. A PLC is an example of a hard real time systemsince output results must be produced in response to input conditionswithin a limited time, otherwise unintended operation will result.

History

Before the PLC, control, sequencing, and safety interlock logic formanufacturing automobiles was mainly composed of relays, camtimers, drum sequencers, and dedicated closed-loop controllers. Sincethese could number in the hundreds or even thousands, the process forupdating such facilities for the yearly model change-over was verytime consuming and expensive, as electricians needed to individually rewire relays to change the logic.

Digital computers, being general-purpose programmable devices, were soon applied to control of industrialprocesses. Early computers required specialist programmers, and stringent operating environmental control fortemperature, cleanliness, and power quality. Using a general-purpose computer for process control requiredprotecting the computer from the plant floor conditions. An industrial control computer would have severalattributes: it would tolerate the shop-floor environment, it would support discrete (bit-form) input and output in aneasily extensible manner, it would not require years of training to use, and it would permit its operation to bemonitored. The response time of any computer system must be fast enough to be useful for control; the requiredspeed varying according to the nature of the process.[1]

In 1968 GM Hydra-Matic (the automatic transmission division of General Motors) issued a request for proposals foran electronic replacement for hard-wired relay systems based on a white paper written by engineer Edward R. Clark.The winning proposal came from Bedford Associates of Bedford, Massachusetts. The first PLC, designated the 084because it was Bedford Associates' eighty-fourth project, was the result.[2] Bedford Associates started a newcompany dedicated to developing, manufacturing, selling, and servicing this new product: Modicon, which stood forMOdular DIgital CONtroller. One of the people who worked on that project was Dick Morley, who is considered tobe the "father" of the PLC. The Modicon brand was sold in 1977 to Gould Electronics, and later acquired by GermanCompany AEG and then by French Schneider Electric, the current owner.One of the very first 084 models built is now on display at Modicon's headquarters in North Andover,Massachusetts. It was presented to Modicon by GM, when the unit was retired after nearly twenty years ofuninterrupted service. Modicon used the 84 moniker at the end of its product range until the 984 made itsappearance.

Programmable logic controller 31

The automotive industry is still one of the largest users of PLCs.

DevelopmentEarly PLCs were designed to replace relay logic systems. These PLCs were programmed in "ladder logic", whichstrongly resembles a schematic diagram of relay logic. This program notation was chosen to reduce training demandsfor the existing technicians. Other early PLCs used a form of instruction list programming, based on a stack-basedlogic solver.Modern PLCs can be programmed in a variety of ways, from the relay-derived ladder logic to programminglanguages such as specially adapted dialects of BASIC and C. Another method is State Logic, a very high-levelprogramming language designed to program PLCs based on state transition diagrams.Many early PLCs did not have accompanying programming terminals that were capable of graphical representationof the logic, and so the logic was instead represented as a series of logic expressions in some version of Booleanformat, similar to Boolean algebra. As programming terminals evolved, it became more common for ladder logic tobe used, for the aforementioned reasons and because it was a familiar format used for electromechanical controlpanels. Newer formats such as State Logic and Function Block (which is similar to the way logic is depicted whenusing digital integrated logic circuits) exist, but they are still not as popular as ladder logic. A primary reason for thisis that PLCs solve the logic in a predictable and repeating sequence, and ladder logic allows the programmer (theperson writing the logic) to see any issues with the timing of the logic sequence more easily than would be possiblein other formats.

ProgrammingEarly PLCs, up to the mid-1980s, were programmed using proprietary programming panels or special-purposeprogramming terminals, which often had dedicated function keys representing the various logical elements of PLCprograms. Some proprietary programming terminals displayed the elements of PLC programs as graphic symbols,but plain ASCII character representations of contacts, coils, and wires were common. Programs were stored oncassette tape cartridges. Facilities for printing and documentation were minimal due to lack of memory capacity. Thevery oldest PLCs used non-volatile magnetic core memory.More recently, PLCs are programmed using application software on personal computers, which now represent thelogic in graphic form instead of character symbols. The computer is connected to the PLC through Ethernet, RS-232,RS-485 or RS-422 cabling. The programming software allows entry and editing of the ladder-style logic. Generallythe software provides functions for debugging and troubleshooting the PLC software, for example, by highlightingportions of the logic to show current status during operation or via simulation. The software will upload anddownload the PLC program, for backup and restoration purposes. In some models of programmable controller, theprogram is transferred from a personal computer to the PLC through a programming board which writes the programinto a removable chip such as an EEPROM or EPROM.

FunctionalityThe functionality of the PLC has evolved over the years to include sequential relay control, motion control, process control, distributed control systems and networking. The data handling, storage, processing power and communication capabilities of some modern PLCs are approximately equivalent to desktop computers. PLC-like programming combined with remote I/O hardware, allow a general-purpose desktop computer to overlap some PLCs in certain applications. Regarding the practicality of these desktop computer based logic controllers, it is important to note that they have not been generally accepted in heavy industry because the desktop computers run on less stable operating systems than do PLCs, and because the desktop computer hardware is typically not designed to the same levels of tolerance to temperature, humidity, vibration, and longevity as the processors used in PLCs. In addition to

Programmable logic controller 32

the hardware limitations of desktop based logic, operating systems such as Windows do not lend themselves todeterministic logic execution, with the result that the logic may not always respond to changes in logic state or inputstatus with the extreme consistency in timing as is expected from PLCs. Still, such desktop logic applications finduse in less critical situations, such as laboratory automation and use in small facilities where the application is lessdemanding and critical, because they are generally much less expensive than PLCs.

Programmable Logic Relay (PLR)In more recent years, small products called PLRs (programmable logic relays), and also by similar names, havebecome more common and accepted. These are very much like PLCs, and are used in light industry where only afew points of I/O (i.e. a few signals coming in from the real world and a few going out) are involved, and low cost isdesired. These small devices are typically made in a common physical size and shape by several manufacturers, andbranded by the makers of larger PLCs to fill out their low end product range. Popular names include PICOController, NANO PLC, and other names implying very small controllers. Most of these have between 8 and 12discrete inputs, 4 and 8 discrete outputs, and up to 2 analog inputs. Size is usually about 4" wide, 3" high, and 3"deep. Most such devices include a tiny postage stamp sized LCD screen for viewing simplified ladder logic (only avery small portion of the program being visible at a given time) and status of I/O points, and typically these screensare accompanied by a 4-way rocker push-button plus four more separate push-buttons, similar to the key buttons on aVCR remote control, and used to navigate and edit the logic. Most have a small plug for connecting via RS-232 orRS-485 to a personal computer so that programmers can use simple Windows applications for programming insteadof being forced to use the tiny LCD and push-button set for this purpose. Unlike regular PLCs that are usuallymodular and greatly expandable, the PLRs are usually not modular or expandable, but their price can be two ordersof magnitude less than a PLC and they still offer robust design and deterministic execution of the logic.

Programmable logic controller 33

PLC topics

Features

Control panel with PLC (grey elements in thecenter). The unit consists of separate elements,

from left to right; power supply, controller, relayunits for in- and output

The main difference from other computers is that PLCs are armored forsevere conditions (such as dust, moisture, heat, cold) and have thefacility for extensive input/output (I/O) arrangements. These connectthe PLC to sensors and actuators. PLCs read limit switches, analogprocess variables (such as temperature and pressure), and the positionsof complex positioning systems. Some use machine vision.[3] On theactuator side, PLCs operate electric motors, pneumatic or hydrauliccylinders, magnetic relays, solenoids, or analog outputs. Theinput/output arrangements may be built into a simple PLC, or the PLCmay have external I/O modules attached to a computer network thatplugs into the PLC.

Scan time

A PLC program is generally executed repeatedly as long as thecontrolled system is running. The status of physical input points iscopied to an area of memory accessible to the processor, sometimescalled the "I/O Image Table". The program is then run from its firstinstruction rung down to the last rung. It takes some time for theprocessor of the PLC to evaluate all the rungs and update the I/O imagetable with the status of outputs.[4] This scan time may be a fewmilliseconds for a small program or on a fast processor, but older PLCsrunning very large programs could take much longer (say, up to 100 ms) to execute the program. If the scan time wastoo long, the response of the PLC to process conditions would be too slow to be useful.

As PLCs became more advanced, methods were developed to change the sequence of ladder execution, andsubroutines were implemented.[5] This simplified programming could be used to save scan time for high-speedprocesses; for example, parts of the program used only for setting up the machine could be segregated from thoseparts required to operate at higher speed.

Special-purpose I/O modules, such as timer modules or counter modules such as encoders, can be used where thescan time of the processor is too long to reliably pick up, for example, counting pulses and interpreting quadraturefrom a shaft encoder. The relatively slow PLC can still interpret the counted values to control a machine, but theaccumulation of pulses is done by a dedicated module that is unaffected by the speed of the program execution.

System scaleA small PLC will have a fixed number of connections built in for inputs and outputs. Typically, expansions areavailable if the base model has insufficient I/O.Modular PLCs have a chassis (also called a rack) into which are placed modules with different functions. Theprocessor and selection of I/O modules are customized for the particular application. Several racks can beadministered by a single processor, and may have thousands of inputs and outputs. A special high speed serial I/Olink is used so that racks can be distributed away from the processor, reducing the wiring costs for large plants.

Programmable logic controller 34

User interfacePLCs may need to interact with people for the purpose of configuration, alarm reporting or everyday control. Ahuman-machine interface (HMI) is employed for this purpose. HMIs are also referred to as man-machine interfaces(MMIs) and graphical user interface (GUIs). A simple system may use buttons and lights to interact with the user.Text displays are available as well as graphical touch screens. More complex systems use programming andmonitoring software installed on a computer, with the PLC connected via a communication interface.

CommunicationsPLCs have built in communications ports, usually 9-pin RS-232, but optionally EIA-485 or Ethernet. Modbus,BACnet or DF1 is usually included as one of the communications protocols. Other options include various fieldbusessuch as DeviceNet or Profibus. Other communications protocols that may be used are listed in the List of automationprotocols.Most modern PLCs can communicate over a network to some other system, such as a computer running a SCADA(Supervisory Control And Data Acquisition) system or web browser.PLCs used in larger I/O systems may have peer-to-peer (P2P) communication between processors. This allowsseparate parts of a complex process to have individual control while allowing the subsystems to co-ordinate over thecommunication link. These communication links are also often used for HMI devices such as keypads or PC-typeworkstations.

ProgrammingPLC programs are typically written in a special application on a personal computer, then downloaded by adirect-connection cable or over a network to the PLC. The program is stored in the PLC either in battery-backed-upRAM or some other non-volatile flash memory. Often, a single PLC can be programmed to replace thousands ofrelays.[6]

Under the IEC 61131-3 standard, PLCs can be programmed using standards-based programming languages. Agraphical programming notation called Sequential Function Charts is available on certain programmable controllers.Initially most PLCs utilized Ladder Logic Diagram Programming, a model which emulated electromechanicalcontrol panel devices (such as the contact and coils of relays) which PLCs replaced. This model remains commontoday.IEC 61131-3 currently defines five programming languages for programmable control systems: function blockdiagram (FBD), ladder diagram (LD), structured text (ST; similar to the Pascal programming language), instructionlist (IL; similar to assembly language) and sequential function chart (SFC).[7] These techniques emphasize logicalorganization of operations.While the fundamental concepts of PLC programming are common to all manufacturers, differences in I/Oaddressing, memory organization and instruction sets mean that PLC programs are never perfectly interchangeablebetween different makers. Even within the same product line of a single manufacturer, different models may not bedirectly compatible.

Programmable logic controller 35

PLC compared with other control systems

Allen-Bradley PLC installed in a control panel

PLCs are well adapted to a range of automation tasks. These aretypically industrial processes in manufacturing where the cost ofdeveloping and maintaining the automation system is high relativeto the total cost of the automation, and where changes to thesystem would be expected during its operational life. PLCs containinput and output devices compatible with industrial pilot devicesand controls; little electrical design is required, and the designproblem centers on expressing the desired sequence of operations.PLC applications are typically highly customized systems, so thecost of a packaged PLC is low compared to the cost of a specificcustom-built controller design. On the other hand, in the case ofmass-produced goods, customized control systems are economical. This is due to the lower cost of the components,which can be optimally chosen instead of a "generic" solution, and where the non-recurring engineering charges arespread over thousands or millions of units.

For high volume or very simple fixed automation tasks, different techniques are used. For example, a consumerdishwasher would be controlled by an electromechanical cam timer costing only a few dollars in productionquantities.A microcontroller-based design would be appropriate where hundreds or thousands of units will be produced and sothe development cost (design of power supplies, input/output hardware and necessary testing and certification) canbe spread over many sales, and where the end-user would not need to alter the control. Automotive applications arean example; millions of units are built each year, and very few end-users alter the programming of these controllers.However, some specialty vehicles such as transit buses economically use PLCs instead of custom-designed controls,because the volumes are low and the development cost would be uneconomical.[8]

Very complex process control, such as used in the chemical industry, may require algorithms and performancebeyond the capability of even high-performance PLCs. Very high-speed or precision controls may also requirecustomized solutions; for example, aircraft flight controls. Single-board computers using semi-customized or fullyproprietary hardware may be chosen for very demanding control applications where the high development andmaintenance cost can be supported. "Soft PLCs" running on desktop-type computers can interface with industrial I/Ohardware while executing programs within a version of commercial operating systems adapted for process controlneeds.Programmable controllers are widely used in motion control, positioning control and torque control. Somemanufacturers produce motion control units to be integrated with PLC so that G-code (involving a CNC machine)can be used to instruct machine movements.[citation needed]

PLCs may include logic for single-variable feedback analog control loop, a "proportional, integral, derivative" or"PID controller". A PID loop could be used to control the temperature of a manufacturing process, for example.Historically PLCs were usually configured with only a few analog control loops; where processes required hundredsor thousands of loops, a distributed control system (DCS) would instead be used. As PLCs have become morepowerful, the boundary between DCS and PLC applications has become less distinct.PLCs have similar functionality as Remote Terminal Units. An RTU, however, usually does not support controlalgorithms or control loops. As hardware rapidly becomes more powerful and cheaper, RTUs, PLCs and DCSs areincreasingly beginning to overlap in responsibilities, and many vendors sell RTUs with PLC-like features and viceversa. The industry has standardized on the IEC 61131-3 functional block language for creating programs to run onRTUs and PLCs, although nearly all vendors also offer proprietary alternatives and associated developmentenvironments.

Programmable logic controller 36

In recent years "Safety" PLCs have started to become popular, either as standalone models or as functionality andsafety-rated hardware added to existing controller architectures (Allen Bradley Guardlogix, Siemens F-series etc.).These differ from conventional PLC types as being suitable for use in safety-critical applications for which PLCshave traditionally been supplemented with hard-wired safety relays. For example, a Safety PLC might be used tocontrol access to a robot cell with trapped-key access, or perhaps to manage the shutdown response to an emergencystop on a conveyor production line. Such PLCs typically have a restricted regular instruction set augmented withsafety-specific instructions designed to interface with emergency stops, light screens and so forth. The flexibility thatsuch systems offer has resulted in rapid growth of demand for these controllers.

Discrete and analog signalsDiscrete signals behave as binary switches, yielding simply an On or Off signal (1 or 0, True or False, respectively).Push buttons, Limit switches, and photoelectric sensors are examples of devices providing a discrete signal. Discretesignals are sent using either voltage or current, where a specific range is designated as On and another as Off. Forexample, a PLC might use 24 V DC I/O, with values above 22 V DC representing On, values below 2VDCrepresenting Off, and intermediate values undefined. Initially, PLCs had only discrete I/O.Analog signals are like volume controls, with a range of values between zero and full-scale. These are typicallyinterpreted as integer values (counts) by the PLC, with various ranges of accuracy depending on the device and thenumber of bits available to store the data. As PLCs typically use 16-bit signed binary processors, the integer valuesare limited between -32,768 and +32,767. Pressure, temperature, flow, and weight are often represented by analogsignals. Analog signals can use voltage or current with a magnitude proportional to the value of the process signal.For example, an analog 0 - 10 V input or 4-20 mA would be converted into an integer value of 0 - 32767.Current inputs are less sensitive to electrical noise (i.e. from welders or electric motor starts) than voltage inputs.

ExampleAs an example, say a facility needs to store water in a tank. The water is drawn from the tank by another system, asneeded, and our example system must manage the water level in the tank by controlling the valve that refills thetank. Shown is a "ladder diagram" which shows the control system. A ladder diagram is a method of drawing controlcircuits which pre-dates PLCs. The ladder diagram resembles the schematic diagram of a system built withelectromechanical relays. Shown are:•• Two inputs (from the low and high level switches) represented by contacts of the float switches•• An output to the fill valve, labelled as the fill valve which it controls•• An "internal" contact, representing the output signal to the fill valve which is created in the program.•• A logical control scheme created by the interconnection of these items in softwareIn the ladder diagram, the contact symbols represent the state of bits in processor memory, which corresponds to thestate of physical inputs to the system. If a discrete input is energized, the memory bit is a 1, and a "normally open"contact controlled by that bit will pass a logic "true" signal on to the next element of the ladder. Internal status bits,corresponding to the state of discrete outputs, are also available to the program.In the example, the physical state of the float switch contacts must be considered when choosing "normally open" or"normally closed" symbols in the ladder diagram. The PLC has two discrete inputs from float switches (Low Leveland High Level). Both float switches (normally closed) open their contacts when the water level in the tank is abovethe physical location of the switch.When the water level is below both switches, the float switch physical contacts are both closed, and a true (logic 1)value is passed to the Fill Valve output. Water begins to fill the tank. The internal "Fill Valve" contact latches thecircuit so that even when the "Low Level" contact opens (as the water passes the lower switch), the fill valve remainson. Since the High Level is also normally closed, water continues to flow as the water level remains between the two

Programmable logic controller 37

switch levels. Once the water level rises enough so that the "High Level" switch is off (opened), the PLC will shutthe inlet to stop the water from overflowing; this is an example of seal-in (latching) logic. The output is sealed inuntil a high level condition breaks the circuit. After that the fill valve remains off until the level drops so low that theLow Level switch is activated, and the process repeats again.

| |

| Low Level High Level Fill Valve |

|------[/]------|------[/]----------------------(OUT)---------|

| | |

| | |

| | |

| Fill Valve | |

|------[ ]------| |

| |

| |

A complete program may contain thousands of rungs, evaluated in sequence. Typically the PLC processor willalternately scan all its inputs and update outputs, then evaluate the ladder logic; input changes during a program scanwill not be effective until the next I/O update. A complete program scan may take only a few milliseconds, muchfaster than changes in the controlled process.Programmable controllers vary in their capabilities for a "rung" of a ladder diagram. Some only allow a single outputbit. There are typically limits to the number of series contacts in line, and the number of branches that can be used.Each element of the rung is evaluated sequentially. If elements change their state during evaluation of a rung,hard-to-diagnose faults can be generated, although sometimes (as above) the technique is useful. Someimplementations forced evaluation from left-to-right as displayed and did not allow reverse flow of a logic signal (inmulti-branched rungs) to affect the output.

References[1] E. A. Parr, Industrial Control Handbook, Industrial Press Inc., 1999 ISBN 0-8311-3085-7[2] M. A. Laughton, D. J. Warne (ed), Electrical Engineer's Reference book, 16th edition,Newnes, 2003 Chapter 16 Programmable Controller[3] Harms, Toni M. & Kinner, Russell H. P.E., Enhancing PLC Performance with Vision Systems. 18th Annual ESD/HMI International

Programmable Controllers Conference Proceedings, 1989, p. 387-399.[4] Maher, Michael J. Real-Time Control and Communications. 18th Annual ESD/SMI International Programmable Controllers Conference

Proceedings, 1989, p. 431-436.[5] Kinner, Russell H., P.E. Designing Programable Controller Application Programs Using More than One Designer. 14th Annual International

Programmable Controllers Conference Proceedings, 1985, p. 97-110.[6] W. Bolton, Programmable Logic Controllers, Fifth Edition, Newnes, 2009 ISBN 978-1-85617-751-1, Chapter 1[7] Keller, William L Jr. Grafcet, A Functional Chart for Sequential Processes, 14th Annual International Programmable Controllers Conference

Proceedings, 1984, p. 71-96.[8] Gregory K. McMillan, Douglas M. Considine (ed), Process/Industrial Instruments and Controls Handbook Fifth Edition, McGraw-Hill, 1999

ISBN 0-07-012582-1 Section 3 Controllers

Programmable logic controller 38

Further reading• Daniel Kandray, Programmable Automation Technologies, Industrial Press, 2010 ISBN 978-0-8311-3346-7,

Chapter 8 Introduction to Programmable Logic Controllers

External links• PLC Control Panels (http:/ / www. ls. orcan. com)• Programmable logic controller (http:/ / www. ls. orcan. com)• PLC Tutorials and Instructions (http:/ / www. ladder-logic. com/ what-is-a-plc/ )• Programmable logic controller (http:/ / www. dmoz. org/ Business/ Electronics_and_Electrical/ Control_Systems/

Programmable_Logic_Controllers/ ) at the Open Directory Project• PLC vs PAC comparison chart at commons.wikimedia.org (https:/ / commons. wikimedia. org/ wiki/

File:PLC_vs_PAC. jpg)• PLC Complete Tutorial (http:/ / www. mbcurl. me/ 6MDE)

Article Sources and Contributors 39

Article Sources and ContributorsR (programming language)  Source: http://en.wikipedia.org/w/index.php?oldid=574583724  Contributors: 2001:720:1014:37:8155:E36F:6C8:39F5,2A02:120B:2C7A:91A0:224:D7FF:FEC6:B370, 777sms, 99of9, Aarktica, Abishekravi, Achristoffersen, Adailton, Adam McMaster, Adamkriesberg, Aitias, Alansohn, Albmont, AlexBehrman,Alfie66, Amkilpatrick, Ammon86, Andreas Kaufmann, Andrew73, Andrewman327, Angelicapple, Angrytoast, Anthon.Eff, Anupparikh, Arunrajmohan, Avenue, BB-Froggy, BD597,Baccyak4H, Belamp, Beland, Belgrano, BenJWoodcroft, Bender235, Bequw, Bhinchliffe, Bikestats, Billymac00, Biomenne, Blauwkoe, Bluemaster, Bob.Muenchen, Bradhill14, Brandon,ButOnMethItIs, Caesura, Calimo, Calinucs, Cardamon, CeciliaPang, Ceranthor, Chrike, Chris the speller, Chrisch, ChryZ MUC, Chuckiesdad, Codename Lisa, CommonsDelinker, Constructiveeditor, CryptoDerk, Cvanca02, DRHagen, Danakil, Davidhorman, Deadlyspider, Dedwen, Den fjättrade ankan, Denislopez, Derek R Bullamore, Diogoprov, Dlautzenheiser, Dmb000006, Docmarseille, Download, Dsp13, Eddelbuettel, Efprime, Ehn, Ehsan.azhdari, ElfQrin, Eliavs, Elwikipedista, Emrahertr, Ephery, Etz Haim, Exaudio, Excirial, Fangz, Faridani, FatalError, Fmark,Fmccown, Forderud, FrankTobia, François Robere, Free Software Knight, Freek de Bruijn, Friedfish, Ftiercel, G2525, Gaborgulya, Gak, Garamond Lethe, Genium, Georgeryp, Gesslein,Ghettoblaster, Giftlite, Gilliam, Gimmetoo, Gjwkayon, Glenn, GongYi, Goodybuddy, GregorB, Grokmenow, Gronky, Gwern, Gzabers, Hairy Dude, Harrietbaulcombe, Hidaspal, Hitchiker42,Hongooi, Inductionheating, Int21h, Ischemia, Ixfd64, J.Voss, JLaTondre, JaeDyWolf, Jarble, Jarekt, Jason Quinn, Jasy jatere, Jdfreivald, Jeff3000, Jeffrey Smith, Jerryobject, Jfmantis,Jim.Callahan,Orlando, Jpag87a, Jtneill, JustinEditor, Karnesky, Keoormsby, Kl4m-AWB, Kmettler, Krexer, Kslays, Kuru, Kvng, Kylecovington, Lampertkm, Landroni, Larry.europe,Lawrencekhoo, Leotohill, LinkTiger, Lixiaoxu, Lovibond, Lswartz, Luke145, Lulu of the Lotus-Eaters, Lupin, Macrakis, Macwhiz, Maechler, Mahanga, Manop, Mark Renier, Markmat, MartinBean, MartinMichlmayr, Masgatotkaca, Mathstat, Maximus Rex, Mcld, Mehmetselim, Melcombe, Melnakeeb, Mhahsler, MicahElliott, Michael Hardy, Minesweeper, Miranche, Mjcraw, Mmm,Mortense, MrOllie, Mrfebruary, MuffledThud, Mutlay, Muzzle, Mwtoews, N5iln, NapoliRoma, Neil.rubens, Neilc, Neuwirthe, Niczar, Nonfamous, Northernhenge, Ntsimp, O18, Ohspite,Omegatron, OverlordQ, Ovis23, OwenBlacker, Panchoh, Peco, Penfold, Persian knight shiraz, Phatsphere, Phil Boswell, PrisonerOfIce, Protonk, Prozaker, Purnank, Pyerre, Qwfp, R-project,RHaworth, RScheiber, Radagast83, Rafesq, Raysonho, Razorflame, RedWolf, Redgecko, Rich Farmbrough, Richierocks, RobSeb, Robinh, RonFredericks, Rstatx, Rursus, Ruud Koot, SF007,SFK2, Sanspeur, Schutz, Scottkosty (usurped), Sdfisher, Sergivs-en, ShelfSkewed, Sherbrooke, Shiki2, Shnout, Shootji, Shyam.sundaram, Sinashahandeh, Slowtortoise4, Smoe, Soumya92,Stan3, StatisticalSoftware, Statr, Stifle, Storm Rider, Stpasha, Sunsetsky, Svick, Talgalili, Tayste, Tdynes, Tech412, Template namespace initialisation script, Tgirke, The Someday,TheMightyPirate, ThorstenStaerk, Thorwald, Thumperward, Thüringer, Tomi, Tony1, Two Bananas, Urod, Vantey, Vonnegutia, Vsb, Vyom25, Waitak, Wavelength, Wccsnow, Where, Widr,Wikidilworth, Winterschlaefer, Winterst, XP1, Xerxes314, Xingmowang, Yonniet, YorkBW, Yworo, Zeileis, Zeno McDohl, ZeroOne, Zoolium, Zven, Σ, 438 anonymous edits

SPSS  Source: http://en.wikipedia.org/w/index.php?oldid=575637982  Contributors: 410678, Aaron Brenneman, Akjar13, Akua07, Alphathon, Arnoutf, Ashawley, BatteryIncluded, Bellagio99,Bequw, Bob.Muenchen, Bobblehead, Boing! said Zebedee, Boxplot, Bradhill14, Bwc21, Caayala, Calimo, Carmen56, Chandler Savage, Chowbok, Clappingsimon, Coconnoribm, Compaqevo,Cordless Larry, DBitengIBM, DanielCD, Dcljr, Deb, Deltahedron, Den fjättrade ankan, Denisarona, Devank, Dr.alf, Dysprosia, Ekostielney, Esrever, Falsifian, Fmph, Fratrep, Frau K, FreeSoftware Knight, Froztbyte, Georgesch4, Giftlite, Glossologist, Gnulxusr, Gogo Dodo, Grantennis, Guglielf, Harizotoh9, Harrietbaulcombe, Hu12, Illia Connell, Inhumandecency, IoannesPragensis, JLaTondre, Jeffq, Jeremymiles, Jnestorius, Joecool.83, John FitzGerald, John Vandenberg, John12212010, Johnbibby, Johndarrington, JorgeGG, Jtneill, Juliakbird, Kashmiri,Kokoe.johnson, Krexer, Kslays, Ktr101, LI Melissa, La-pays, Landroni, Lankiveil, Laurusnobilis, LibaryGeek, Ljhenshall, LuK3, MFSchar, MK8, Mabdul, Marion.cuny, Masgatotkaca,Materialscientist, Matttoothman, Mattymatt, Mdrain, Mogism, MrOllie, Mvanwaveren, Nono64, Not Sure, Nsajjads, O18, Oodely, Padawan ch, Palfrey, Peckjonk, Pemboid, Perfecto,Perohanych, Peter Flass, Piotrus, Pontificake, Programming gecko, Pterre, Quercus solaris, Qwfp, R'n'B, Rembrandt, Remember the dot, Ricklaman, Rickyrab, Rjanag, Rjwilmsi, RolandUnger,Roundquarter, SPSSkid, Samunoz1, Saxifrage, Schul253, Schwnj, Senator2029, Shizhao, Shortride, Skrillex-27, Sludge, Sstolarik, Stannered, StatisticalSoftware, StatsWombat, Stevenmitchell,Strangebuttrue, Superzohar, Syrthiss, TKD, Tabletop, TedPavlic, Themanintheshack, Tholme, TinJack, Tizio, Tom harrison, Tomtheeditor, V95micfa, Vanischenu, Vrenator, Wajiha nasir19,Wakebrdkid, Wayiran, Wernher, WhiteDragon, WikHead, Wikipelli, William Avery, Worm That Turned, Zzuuzz, 229 anonymous edits

SAS (software)  Source: http://en.wikipedia.org/w/index.php?oldid=575513552  Contributors: AJLCary, Adragulescu, Alansohn, AlexAnglin, Andy4789, Anon lynx, Arjayay, Aurorion,Avenue, B.gauthier.quebec, Baccyak4H, Barefootguru, Bensin, BlaiseFEgan, Bob.Muenchen, Bobdc, Boxplot, Bradhill14, Brokenwhole, Bruce Tindall, Btyner, COIDave, CUTKD, Can't sleep,clown will eat me, Charles Edwin Shipp, Chris9594, Codename Lisa, Colonies Chris, CorporateM, Cp18010, Crysb, Cybercobra, D6, DagnyB, Daydayup1, Dcoetzee, DeaconJJG, Den fjättradeankan, Dirtyd, Diser55, Dlibby, DocendoDiscimus, Docu, Dvdpwiki, Ehn, Elsieharpist, Elwikipedista, Erkan Yilmaz, Foxyjiji, Free Software Knight, Fuhghettaboutit, Fujiiiii, G716, GaiusCornelius, Getsecure, Gioto, Giraffedata, Goldom, Guy Macon, Gzuckier, Hirak 99, Hohum, Hu12, Inquam, Iridescent, John of Reading, John12212010, Jonadin93, Josquin021, Jowa fan,Jthetzel, Jwoodger, KaySL, Koavf, Komap, Krexer, Kronlin, Kslays, Kuru, L8fortee, Lambiam, Laughing Man, Lendu, LilHelpa, Lizclare, Luke145, M. Frederick, MC MasterChef, Malachit,Mark Renier, Martinolsvenne, Masgatotkaca, Matias.Reccius, Matthiaspaul, Mayur, Mbeychok, Metamusing, Mircea cs, Mm03480, Montura, MrOllie, Mwtoews, Nbarth, Nbuijt, Nelisroos,NetDominus, Nils wiese dk, Nivektrah, Nogggs, Ntroutman, O18, Ospalh, Oxyfan, Ozzyslovechild, PAC2, Pagrashtak, Pchoate, Pegua, Peter Chastain, Pietrow, Pinethicket, Puddin' Man,Quokly, Qwertyus, Qwfp, R'n'B, RG2, Reedy, Rhphillips, Rich Farmbrough, Rjwilmsi, RogerLustig, Rtcoles, Ruud Koot, Sandman888, Semicolonneeded, Shadowjams, Shaunm, Shirahadasha,Sietse Snel, SimonP, Smileylich, Squids and Chips, Stanking, Stephan Leeds, Superm401, Technopat, TheTrueMikeBrown, Thobach, Thumperward, Tomatonose, Topbanana, Tygrus, Vikjam,Vlad, Wernher, Wikid77, Wimmeljan, Winterst, Woodpecker.ch, Woodshed, Woohookitty, Ypacaraí, Zach425, Ὁ οἶστρος, 286 anonymous edits

Larsen & Toubro  Source: http://en.wikipedia.org/w/index.php?oldid=574715961  Contributors: 219.106の 者, AEJ, AMARNATH 1994, Aaditya 7, Abhijamo, Abhishekchavan79, Adavidb,Akabaripiyush, Alexius08, Amdavadi81, Amitkinger, Aniket Shedge, Aquillion, Arjun024, Arun capri, Banarani, Baronnet, Beagel, Bedaninaresh, Belovedfreak, Ben Ben, Bhadani, Bhuwansing,Biblbroks, Biker Biker, BrightStarSky, Callrecall911, Captain Conundrum, Chaitanya.lala, Chandru s, Chintan-kumar, Chirags, Chowbok, Chris the speller, Clapurhands, Cntras, CorporateM,Crazysoul, DadaNeem, Dewan357, Dulciana, Ekabhishek, Enigma Blues, EoGuy, Extra999, Flint McRae, Fram, Full2fun2sh, GDibyendu, Gaius Cornelius, Ganesh dvr, Garygoh884,Gerhardvalentin, Gilliam, Ginsuloft, Gogo Dodo, GoingBatty, Hamidshah, Hardikvasa, Hemanshu, I dream of horses, Immunize, Indersargodhia, IndianGeneralist, Inwind, Iridescent,Itsbiprangshu, J36miles, JaGa, Jac16888, Jamcib, Jethwarp, Joe Kress, Johnuniq, Jonkerz, Jovianeye, JustAGal, Khazar, King Zebu, Kkm010, KuwarOnline, LNTCorpcomm, Leszek Jańczuk,Lightmouse, LnTEmSyS, Lntccdpr, Lovysinghal, Ltinfra, MKar, MMS2013, Magesh11, Magioladitis, Mahesharabole, Mandarax, Manishsama, Materialscientist, MaximvsDecimvs, Mayur k100,Mean as custard, Mild Bill Hiccup, Mitravanu, Mks86, Moeng, Moriori, Msec109, Murtyabc143, Nasriram, Natrajdr, Nichalp, Nishant nsp, Novemfructus, P.sachin.nayak, Pappudurga,PatrickFlaherty, Pearle, Phanstar, PhilKnight, Pokalarudra, Pos, Prashantserai, Pratik.mallya, Quebec99, R'n'B, R2212xx, Randhirreddy, Ranjitace01, RavindraGadagkar, Reconsider the static,RedRollerskate, Rjwilmsi, Rocketrod1960, Rohitagarwals, Rohitrohit, Rsrikanth05, RyanGerbil10, S3000, SFK2, Sahils1512, Samprashanth, Sau6402, Seaphoto, Shadowjams, Sherool, Shietal,Shietal ramesh, Shortride, Shrikanthv, Shyamsunder, Skcpublic, Smartse, Somnathk, Sonu iert, Soumyyaa, Sridarshan23, Sumit Kumar, Sumsnl, Sun Creator, Svpurohit, Tejakrishna, The Nut,The wub, Theroadislong, Threek85, Tkynerd, Trinidade, Uday chikorde, Utcursch, Vimalkalyan, Vipinhari, Vishwaman, Vivvt, WBRSin, Way2bhushan, WikHead, Woohookitty, Wtmitchell,Ww2censor, Xionbox, Yndesai, Yogesh4ever, Zegr8, 434 anonymous edits

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Image Sources, Licenses and Contributors 40

Image Sources, Licenses and ContributorsImage:Rlogo.png  Source: http://en.wikipedia.org/w/index.php?title=File:Rlogo.png  License: GNU General Public License  Contributors: R Foundation, from http://www.r-project.orgfile:Wikibooks-logo-en-noslogan.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Wikibooks-logo-en-noslogan.svg  License: logo  Contributors: User:Bastique, User:Ramac et al.File:Plots from lm example.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Plots_from_lm_example.svg  License: Creative Commons Attribution-Sharealike 3.0,2.5,2.0,1.0 Contributors: CalimoFile:Mandelbrot Creation Animation.gif  Source: http://en.wikipedia.org/w/index.php?title=File:Mandelbrot_Creation_Animation.gif  License: Creative Commons Attribution-Share Alike Contributors: JarektFile:Ibm-spss-statistics-17.png  Source: http://en.wikipedia.org/w/index.php?title=File:Ibm-spss-statistics-17.png  License: unknown  Contributors: Senator2029File:SPSS logo.svg  Source: http://en.wikipedia.org/w/index.php?title=File:SPSS_logo.svg  License: Public Domain  Contributors: Froztbyte ()File:SAS Institute logo.png  Source: http://en.wikipedia.org/w/index.php?title=File:SAS_Institute_logo.png  License: Public Domain  Contributors: SAS Institute Inc.File:Increase2.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Increase2.svg  License: Public Domain  Contributors: SarangFile:Decrease2.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Decrease2.svg  License: Public Domain  Contributors: SarangImage:Siemens Simatic S7-416-3.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Siemens_Simatic_S7-416-3.jpg  License: Public Domain  Contributors: MixabestImage:PLC Control Panel.png  Source: http://en.wikipedia.org/w/index.php?title=File:PLC_Control_Panel.png  License: Public Domain  Contributors: Original uploader was Dailynetworks aten.wikipediaFile:BMA Automation Allen Bradley PLC 3.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:BMA_Automation_Allen_Bradley_PLC_3.JPG  License: Creative CommonsAttribution-Sharealike 3.0  Contributors: Elmschrat Coaching-Blog

License 41

LicenseCreative Commons Attribution-Share Alike 3.0//creativecommons.org/licenses/by-sa/3.0/