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Chapter 5: Architectural requirements of EC

IT357 Electronic Commerce

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Architectural requirements of EC

1. Telecommunication infrastructure

2. Decision support systems

3. Interoperability

4. Storage and retrieval of multi media information

5. Markup languages

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Architectural requirements of EC

• Scalable• Enables resource sharing• Supports asymmetrical protocols• Provides transparency of data locations and decision

support• Also supports multi-media information, allow mix and

match of various software and hardware platforms

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Telecommunication infrastructure• OSI - Open Systems Interconnection: Proposed by the International Standards Organization• The goal - to allow one computer to communicate with another irrespective of its origin or

manufacturer.

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Cont’d: Telecommunication infrastructure Open Systems Interconnection

1. Physical Layer

– Consists of the transmission media for the bit streams and its interface with computers, e.g. fiber optic cables

2. Data link layer– Concerned with information transmission over a single

channel or link.• Acknowledgement of transmissions• Error detection• Sequencing• E.g. Ethernet, ATM

– The data link layer is often implemented in software as a "network card driver".

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Cont’d: Telecommunication infrastructure Open Systems Interconnection

3. Network Layer– Enables simultaneous use of multiple links to increase

transmission performance.• Routing• Flow control• End to end ack for multi link paths

• Host to network interfaces Data link layer

– Responsible for end to end packet delivery

4. Transport Layer– Network addressing

– Establishment of virtual circuits

– Procedures for entering and departing from the network.

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Cont’d: Telecommunication infrastructure Open Systems Interconnection

5. Session Layer– Concerned with establishing communications between

given pair of users – Starting, stopping and controlling the communication.

6. Presentation Layer

– Display formatting and editing of inputs and outputs

7. Application Layer

– Concerned with the business functions the users are trying to perform.

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Cont’d: Telecommunication infrastructureTCP/IP

• Covers the top layers of the OSI excluding the Physical and Data link layers

ATM

• Real-time transmission of multi-media data

• Interoperable with local, metropolitan and wide area networks

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Decision support systemsData warehouses

• Refers to a collection of data that is– Subject oriented – Integrated – Time varying – Non volatile and – Designed to support faster and better decision making

• Data warehouses Vs. Transaction Systems– A data warehouse application focuses on data analysis

(Online analytical processing - OLAP)– A traditional database application emphasizes on Online transaction

processing – OLTP– Data warehouse applications require summarized historical data derived

from internal and external sources.– OLTP applications require detailed current data derived primarily from

internal sources.– Data warehouse is several orders of magnitude larger than an operational

data base.

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Decision support systemsDeveloping OLAP applications:

• Multiple sources of data pose difficulties:– Inconsistency in data representation coding and format

– Erroneous and incomplete data

• Data Cleansing– Done by data migration tools such as Warehouse Manager that rely

on the user to define the mappings between source and target data.

• Loading and uploading data– Refers to the process of populating the data warehouse from

external data sources.

– Preprocessing needed for integrity checking, sorting summarization aggregation and data partitioning (for parallel loading).

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Decision support systemsDeveloping OLAP applications

• Refreshing data warehouses

– Refreshing the data warehouse based on the changes to the operational database is important.

– Can be done by:• Synchronous replication

– Provides tight consistency between data stores with zero latency– Expensive and not essential in many applications

• Asynchronous replication– A table in the warehouse is treated as a remote copy of the table

in the operational database.– The actual updating is done at a later time .

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Decision support systemsKnowledge Discovery in Databases (KDD)

– Refers to the tools and techniques used to analyze data in organizational databases to find useful patterns in data.

Data Mining

• Deals with specific algorithms and methodologies for data analysis with the intent of finding useful patterns.

• Consists of two tasks:– Prediction - Identification of unknown values for the variables of interest– Description - Analysis of data in humanly interpretable forms.

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Interoperability

• Interoperability provided by:• CORBA

– Common Object Request Broker Architecture– Object Management Group’s (OMG) open distributed object

computing infrastructure.

– Allows applications to communicate with one another irrespective of the location or design.

• Software agents

– Computer programs that employ AI techniques to provide active assistance to users with computer based tasks.

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Interoperability How does CORBA ensure interoperability?

• The clients and objects interact using one or more Object Request brokers (ORB)

• ORB is the middleware that establishes the client server relationships between objects.

• Using an ORB a client can invoke a method on a server object, which can be on the same machine or across a network.

• The ORB intercepts the call and is responsible for – finding an object that can implement the request

– passing the parameters

– invoking its method

– returning results

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Interoperability Software Agents

• Assist users in different ways• Information filtering• Information retrieval• Mail management• Meeting scheduling• Selection of books, music etc.

• Example: Maxims - An agent that helps with e-mails.– Learns to prioritize, delete, forward, sort and archive mail messages on

behalf of the user.• PersonaLogic - PersonaLogic allows users to specify product features

uses a constraint satisfaction algorithm to filter through product space to retrieve an ordered set of products.

• Firefly - uses an automated collaborative filtering method to rate and recommend products to shoppers.

• BargainFinder and Jango– Takes a product name as input, obtains price information from other web

sites and offers a price comparison.

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Storage and retrieval of multi media information

• Based on collecting content representative metadata - data about media objects stored

• Metadata is classified as:– Content dependant – Content descriptive– Content independent– The metadata has to have efficient linkages with the physical

location of the information.– The data retrieved should be presented to the users in the

decreasing order of retrieval status value• Objects are stored in digital libraries based on feature

similarity.• A feature is a set of characteristics such as text strings in text

documents, colour texture and objects in video frames.• These features can be used to index and retrieve objects

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Storage and retrieval of multi media information

• Storage strategy is based on:– Type of object– Retrieval requirements of the stored object.

• Storage strategies can be classified under:– Single disk storage– Multiple disk storage– Multiple disk storage with data striping

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Markup Languages

• Markup - originally used to describe annotations or other marks within a text to instruct a typist how a passage should be laid out.

• Markup language - a set of mark up conventions used for encoding of texts.

• A markup language must specify:– What markups are allowed– What markups are required– How markups are distinguished from text– What markup means

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Markup Languages

• SGML– Describes a generalized mark up scheme for representing

the logical structure of the document in a system and platform independent manner.

– Uses a Document Type Definition (DTD) model to describe each element of the document

– Different documents of the same DTD can be processed uniformly.

– Programs can be written to take advantage of the structure information and made to behave more intelligently.

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Markup Languages

• HTML– Invented by Tim Bernes Lee– The publishing language of the WWW.– Gives users means to:

• Publish online documents• Retrieve online information• Design forms for conducting transactions with remote services• Include spread sheets, video clips etc in the documents

– Drawbacks• Does not support encoding of the structure and meaning of structured

documents -e.g. spread sheets, address books, technical drawings etc.• Thus such documents cannot be effectively indexed or searched.

• Formal descriptions of content and services are absent - Automated information extraction from HTML pages is therefore difficult

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Markup Languages

• XML– Relatively New– Combines the merits of HTML and SGML– Used for designing text formats for structured data such as spread sheets

and address books.• XML vs HTML

– Uses tags (<words>)and attributes (name=“value”) just like HTML– But the interpretation of the tags is left to the application entirely.

• XML Characteristics– XML files are text files meant to be read by programs or programmers.– Programmers can debug applications more easily in XML.– Unlike HTML errors are not tolerated– XML files are larger than comparable binary formats.– Is license free, platform independent and well supported

• XBRL