INFSCI 00102015 Summer Term

LEC6.ppt

Becoming Skilled at Information Technology

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IS 0010 - Summer 2015

Tentative Schedule Week of

(Monday)

1 11-May x2 18-May x3 25-May Memorial Day (no classes)4 1-Jun x5 8-Jun x6 15-Jun x7 22-Jun x8 29-Jun9 6-Jul Exam

10 13-Jul11 20-Jul Presentations12 27-Jul Final work due

Assignments due next class

• The exam questions assignment is due next class• WepagePart1.ppt is due next class

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Current assignment summary• Bring an INFSCI article to each class

– Due: each class … (ref LEC1)

• Start reading the text– Due: before the exam … (ref LEC1)

• Watch “Code Wars” video– http://www.intellectualtakeout.org/library/video-podcast-media/video-code-wars-america%E2%80%99s-

cyber-threat– Due: before the exam … (ref LEC1)

• Exam questions assignment– Due: one week before the exam (6/29/15) … (ref LEC2)

• WebpagePart1.ppt (ref LEC5)

– Due: one week before the exam (6/29/15)

• GroupProject.ppt• Spreadsheet.doc << new << due end of term• Extra articles

– Net Neutrality due: 6/1/15 … (ref LEC2)– Patriot Act due: 6/8/15 … (ref LEC3)– Drones due 6/22/15 … (ref LEC5)

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Looking aheadchapters for text version 6

• Future topics include:– Webpage online, spreadsheet, javascript, database +++

• There are a lot of good sources for learning and developing fluency with these topics. The associated text chapters include:– Spreadsheet: 13,14– Javascript:17,18– Database: 15,16

Lecture Notes

• You now have:– LEC1.ppt, LEC2.ppt, LEC3.ppt, LEC4.ppt,

LEC5.ppt, LEC6.ppt– CH1v6.ppt, CH2v6.ppt, CH3v6.ppt,

CH4v6.ppt, CH5v6.ppt, CH7v6.ppt– WebpagePart1.ppt– GroupProject.ppt– Spreadsheet.doc

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Current reading list

• Read Chapters 1,2,3,4,5,7,8,9 (Versions 5 and 6)• Read Chapters 1,2,3,4,5,8,9,11(Old Version 4)

• No assigned due date (reference class discussion)

Five civilian uses of drones(National Geographic - 2013)

• Five civilian uses of drones:• 1. Hurricane Hunting• Drones can charge into the heart of a storm without risking human life and limb. That's one reason NASA, the National Oceanic and

Atmospheric Administration (NOAA), and Northrop Grumman teamed up on a three-year, $30-million experiment to use long-range Unmanned Aerial Vehicles (UAV) to spy on storms as they evolve.

• 2. 3-D Mapping• Small, lightweight drones may look like simple model airplanes, but they can survey landscapes with thousands of digital images that can

be stitched together into 3-D maps. Military and other government satellites produce similar maps, but emerging UAV technology can put that capability in the hands of small companies and individuals, to be customized and used for a seemingly endless variety of applications.

• 3. Protecting Wildlife• The U.S. government already uses drones to protect its lands and the species that inhabit them. The Department of the Interior, the

Bureau of Land Management, and the United States Geological Service use UAVs, to monitor wildlife populations or map roads and wetlands for land management purposes.

• Drones also lend punch in the fight against poaching. With funding from Google, the conservation giant WWF plans to launch surveillance drones this year in skies over Africa, where poaching is driving iconic species like rhinos toward extinction and is fueling a massive illegal trade in wildlife items like horns and ivory.

• 4. Farming• Farmers use drone technology to monitor fields and deliver pesticides, water, or fertilizers. Drones can help by identifying exactly where

such resources are needed and delivering them there, is better for the environment and for a farmer's bottom line.• Drone cameras an spot where nitrogen levels are low, or watch the growth of a specific field section, or use of infrared light cameras can

reveal plant health by reflecting how efficient photosynthesis is in various plants.• 5. Search and Rescue• An injured victim of an automobile accident in Saskatchewan, Canada, in May 2013 may have been the first person to have his life saved

by a search-and-rescue drone. A ground search and an air ambulance helicopter with night-vision gear failed to find him but a drone with heat-sensing equipment, launched by the Mounties, found the victim before a potentially fatal night outdoors in subfreezing temperatures.

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Drones• http://blogs.discovermagazine.com/drone360/2015/06/18/huge-iceberg-collapse-

captured-in-drone-video/• 5 uses of drones: http://news.nationalgeographic.com/news/2013/12/131202-drone-

uav-uas-amazon-octocopter-bezos-science-aircraft-unmanned-robot/• http://www.techworld.com/picture-gallery/personal-tech/6-best-uses-of-drones-in-

business-3605145/#8• Yesterday, Federal Aviation Administration Deputy Administrator Michael Whitaker

said that “within a year” a plan would be in place for commercial drones to operate in a public space. Reuters followed the announcement up with a very short report saying that Amazon “expects to have drone technology ready” as soon as these plans are announced. (6/18/15 gizmodo.com)

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Amazon delivery

• http://www.youtube.com/watch?v=Le46ERPMlWU

Group project

• Groups meet at the end of class

• GroupProject.ppt

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Goto Spreadsheet.doc

• Spreadsheet.doc

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Representing information digitally

• Reference text chapter 7

Telecommunicationsdigital

• Telecommunications: communicating over a distance

• How to communicate (over a distance):– Voice– Data– Image– Video

Digital

• How to represent data digitally continued

Text representation (data)

Binary Oct Dec Hex Character

100 0000 100 64 40 @

100 0001 101 65 41 A

100 0010 102 66 42 B

100 0011 103 67 43 C

Binary Oct Dec Hex Character

110 0000 140 96 60 `

110 0001 141 97 61 a

110 0010 142 98 62 b

110 0011 143 99 63 c

Binary to decimal

• The binary (base two) numeral system has two possible values, often represented as 0 or 1, for each place-value. In contrast, the decimal (base ten) numeral system has ten possible values (0,1,2,3,4,5,6,7,8, or 9) for each place-value.

Binary to decimalref: http://www.sciencehq.com/computing-technology/binary-to-decimal-conversion.html

Binary to Decimalconversion example

reference: http://learn-networking.com/network-design/a-guide-to-network-math

Representing information

• How can we represent 1111 using fewer symbols? Can we use just one symbol?

Hex

• Ref: text v5/6 chapter 7

• Ref: text v4 chapter 8

Hexadecimal

• From Greek, hexadecimal is a word meaning "sixteen." • Decimal=10 • Hexadecimal=16 • In the hexadecimal system, 6 letters are added to the

standard 0-9 Arabic Numerals, to give you a numbering system with base 16, instead of base ten.

• Decimal : 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 • Hexadecimal: 0 1 2 3 4 5 6 7 8 9 A B C D E F

Color

• How do we see color?

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How do we see color?• The retina of the eye contains two types of photoreceptors which are sensitive to light: cones

and rods. Rods process light at lower levels of illumination while cones process at higher levels. The light energy which is absorbed by the cones and rods is converted into chemical and electrical signals. These signals are processed by the neurons of the eye and the brain.

• Three different types of cone cells in the eye process different wave lengths of the visible spectrum.

• Cones are used to perceive color. There are three types, each being more sensitive to a different part of the visible spectrum. The three types are called

• •short-wavelength sensitive cones• •middle-wavelength sensitive cones• •long-wavelength sensitive cones• They are also called S-cones, M-cones and L-cones. Sometimes they are referred to as R-

cones, G-cones and B-cones (for red, green and blue), however that is a simplification and not quite accurate. For example, the very short wavelengths will only stimulate the S-cones, but the color sensation will have both a reddish and a bluish component.

• Perceived Color• The color we perceive is the result of comparisons of the amount of light absorbed by the

different cone types. What the different types of cone cells output is processed by our visual system to determine the color we perceive. This process occurs at different stages, starting at the retina and ending at the cerebral cortex in the brain.

• http://www.eye-therapy.com/Color/• http://www.pantone.com/pages/Pantone/Pantone.aspx?pg=19357&ca=29

Frequency spectrum - colors

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RGB Color Values

• Colors are displayed combining RED, GREEN, and BLUE light.

• HTML colors are defined using a hexadecimal (hex) notation for the combination of Red, Green, and Blue color values (RGB). The lowest value that can be given to one of the light sources is 0 (hex 00). The highest value is 255 (hex FF).

• Hex values are written as 3 double digit numbers, starting with a # sign.

RGB• The RGB color space is an additive color space in which red, green, and blue light are

combined in various ways to create other colors. • Zero intensity for each component gives the darkest color (no light, considered the black), and

full intensity of each gives a white;• A secondary color is formed by the sum of two primary colors of equal intensity: cyan is

green+blue, magenta is red+blue, and yellow is red+green.• The HTML standards have listed only 16 valid color names (which is limited):

aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, and yellow.

• If you want valid HTML use the HEX values instead : Six digit hexadecimal color codes like '#99CCFF' or '#0033CC'

• When written, RGB values are commonly specified using three integers between 0 and 255, representing red, green, and blue intensities, in that order. For example:

– (0, 0, 0) is black – (255, 255, 255) is white – (255, 0, 0) is red – (0, 255, 0) is green – (0, 0, 255) is blue – (255, 255, 0) is yellow – (0, 255, 255) is cyan – (255, 0, 255) is magenta

HTML Colorshttp://www.w3schools.com/html/html_colors.asp

Color Color HEX Color RGB

  #000000 rgb(0,0,0)

  #FF0000 rgb(255,0,0)

  #00FF00 rgb(0,255,0)

  #0000FF rgb(0,0,255)

  #FFFF00 rgb(255,255,0)

  #00FFFF rgb(0,255,255)

  #FF00FF rgb(255,0,255)

  #C0C0C0 rgb(192,192,192)

  #FFFFFF rgb(255,255,255)

HTML attributes to specify color• HTML Attributes to Specify Color <BODY BGCOLOR="#ff6600"> sets the background color for the page as a whole.

Compatibility Notes: The <body> bgcolor attribute ++ is not supported in HTML5Reference: http://www.w3schools.com/tags/att_body_bgcolor.asp

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Color

• This is a site Color Schemes for matching colors for your web page

• http://www.hypergurl.com/colormatch.php

Panda

• Text v4 chapter 8 / Text v6 chapter 7

Networking

• Reference text chapter 3

Communicating information

• Invent a 7 letter alphabet

• How many bits to represent a letter?

• How many bits in the word BAD?

• Transmit the word BAD

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Invent a code to represent letters:

1 A 0 0 0 2n >= 72 B 0 0 1 n = 3 3 C 0 1 04 D 0 1 15 E 1 0 06 F 1 0 17 G 1 1 08 ? 1 1 1

B A D B 0 0 1 BA 0 0 1 0 0 0 BAD 0 0 1 0 0 0 0 1 135

Signals and information

• Analog and digital signals:

• Analog signal communicating digital information:

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Transmission error?

• How can we detect a transmission error?

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Parity

Ref text v6 page 199

Ref text v4 page 241

Simple error detection

• A parity bit is a bit that is added to ensure that the number of bits with value of one in a given set of bits is always even or odd. Parity bits are used as the simplest error detecting code.

• As for binary digits, there are two variants of parity bits: even parity bit and odd parity bit. – An even parity bit is set to 1 if the number of ones in a

given set of bits is odd (making the total number of ones, including the parity bit, even).

– An odd parity bit is set to 1 if the number of ones in a given set of bits is even (making the total number of ones, including the parity bit, odd).

Error checking

EVENPARITY

B A D BAD 0 0 1 0 0 0 0 1 1 1

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Packet Switching Illustration

POTS / PSTN

• Plain Old Telephone System

• Public Switched Telephone Network

Circuit switched vs packet switched networks

Networksgeographic

• PAN = Personal Area Network

• LAN = Local Area Network

• MAN = Metropolitan Area Network

• WAN = Wide Area Network

• http://www.techopedia.com/2/29090/networks/lanwanman-an-overview-of-network-types

Other network acronyms

• PAN– NFC

• WLAN

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LAN

• Networking information

• LAN Ethernet, Token ring, other

LAN EXAMPLE:• CSMA/CD Ethernet

• In networking, the term protocol refers to a set of rules that govern communications. Protocols are to computers what language is to humans.

• The Ethernet protocol specifies a set of rules for constructing and transferring frames.

• The IEEE standard 802.3 standardizes the operation of a CSMA/CD network.

Ethernet

• In 1973, at Xerox PARC researcher Bob Metcalfe designed and tested the first Ethernet network.

• Ethernet uses Manchester Encoding for coding the data bits on the outgoing signal.

Ethernet Terminology• Medium - Ethernet devices attach to a common medium that provides a

path along which the electronic signals will travel. Historically, this medium has been coaxial copper cable, but today it is more commonly a twisted pair or fiber optic cabling.

• Node - Devices that attach to that segment are stations or nodes.• Packet - The nodes communicate in short messages called packets,

which are variably sized “chunks” of information. (also called frames ..)

CSMA/CD

• What is CSMA/CD

• What uses CSMA/CD

• How does CSMA/CD work?

• Short for Carrier Sense Multiple Access / Collision Detection, a set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously (called a collision). Standard Ethernet networks use CSMA/CD to physically monitor the traffic on the line at participating stations. If no transmission is taking place at the time, the particular station can transmit. If two stations attempt to transmit simultaneously, this causes a collision, which is detected by all participating stations. After a random time interval, the stations that collided attempt to transmit again. If another collision occurs, the time intervals from which the random waiting time is selected are increased step by step. This is known as exponential back off. CSMA/CD is a type of contention protocol.  Networks using the CSMA/CD procedure are simple to implement but do not have deterministic transmission characteristics. The CSMA/CD method is internationally standardized in IEEE 802.3 and ISO 8802.3.

Traditional Ethernet

• Ethernet and CSMA/CD (IEEE 802.3)• Carrier sense multiple access with collision

detection• Four procedures:

– If medium is idle transmit– If medium is busy, listen until idle and then transmit– If collision is detected, cease transmitting– After a collision, wait a random amount of time before

retransmitting

Linear Bus

• A linear bus topology consists of a main run of cable with a terminator at each end. All nodes (file server, workstations, and peripherals) are connected to the linear cable. Ethernet and LocatTalk networks use a linear bus topology

CSMA/CD example

• (See next slide)

• A transmits at t0

• Both B and C are ready to transmit at t1

• B senses A’s transmission and defers

• A’s transmission hasn’t reached C yet so C transmits

1 byte = 8 bits 1 nibble = 4 bits

Ring

Token Ring

• Status of Token Ring Protocol

• Token Ring Protocol was patented by IBM in 1981. IBM enjoyed early success with this network arrangement until Ethernet became the standard for local area networks (LANs). It is still used today in some specialized installations.

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Token ring

• The ring initializes by creating a token, which is a special type of frame that gives a station permission to transmit.

• The token circles the ring like any frame until it encounters a station that wishes to transmit data.

• This station then "captures" the token by replacing the token frame with a data-carrying frame, which encircles the network.

• Once that data frame returns to the transmitting station, that station removes the data frame, creates a new token and forwards that token on to the next node in the ring.

Switched Ethernet

• Switched EthernetModern Ethernet implementations often look nothing like their historical counterparts. Where long runs of coaxial cable provided attachments for multiple stations in legacy Ethernet, modern Ethernet networks use twisted pair wiring or fiber optics to connect stations in a radial pattern. Where legacy Ethernet networks transmitted data at 10 megabits per second (Mbps), modern networks can operate at 100 or even 1,000 Mbps!

Ethernet Hubs and Switches

• Shared medium hubs

• Switched LAN hubs x

IEEE standards• 802.11b, g, n, etc

– The IEEE standard for wireless networking– New >> 802.11ac

• 802.3– IEEE standard for CSMA/CD (Ethernet) access

method

Analog waves

Metaphor

• Computer metaphor – an icon or image used as representative or symbolic of a computation (text v4 page 31 / text v5 page 41)

Metaphor -example