Exam 2 Review

June 16, 2015

Info. Systems in OrganizationsDecision Making

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IS & Hierarchical Organizational structure

• .

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Administrative Information Systems• Transaction Processing Systems (TPS)

– Basic business system that serves the operational level (including analysts) in organizations

– Capture & process data generated during day-to-day activities

• Office Automation Systems (OAS)– Systems designed to help office workers in doing their job.

• Decision Support Systems (DSS)– Systems designed to support middle managers and business

professionals during the decision-making process

• Executive Information Systems (EIS) or Executive Support Systems (ESS)– Specialized DSS that help senior level executives make decisions.

• GDSS: computer-based systems that facilitate solving of unstructured problems by set of decision makers

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Organization & IS: another view

Top Management

Middle Management

Lower Management

Operational workers

Officeworkers

Officeworkers

Officeworkers

Officeworkers

Knowledgeworkers

Types of Information Systems:

- Transaction Processing Systems- Office Automation Systems- Knowledge Worker Systems- Management Information Systems- Decision Support Systems- Executive Information Systems

Q: What kind of IS are designed to provide help for decision makers?

Questions

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Decision Making process

Simon’s decision-making process model Intelligence Design Choice (Implementation)

Newell, A., and Simon, H. A. (1972). Human problem solving Englewood Cliffs, Prentice-Hall, New Jersey.

Simon, H. (1955), A Behavioral Model of Rational Choice, Quarterly Journal of Economics, vol. 69, 99–188

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Intelligence Phase

• Scan the environment for a problem.

• Determine if problem is real, important enough, solvable

• Determine if problem within their scope of influence?

• Fully define the problem by gathering more information.

Scan Environment forproblem to be solved

or decision to be made

Data source

Organizational IS & external

data

Problem ? END

Problem within scope of influence?

No

Yes

ENDNo

Gather more informationabout the problem

Internal & External data

Yes

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Design Phase

• Develop a model of the problem.– Determine type of

model.

• Verify model.

• Develop and analyze potential solutions.

Develop a model ofproblem to be solved

Verify that the model is accurate

Develop potentialsolutions

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Choice Phase

• Evaluate solutions and select the solution to implement.– More detailed analysis of selected solution

might be needed.– Verify initial conditions.– Analyze proposed solution against real-world

constraints.

Questions

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DSS structureSystems designed to help middle

managers make decisionsMajor components

– Data management subsystem• Internal and external data sources

– Analysis subsystem• Typically mathematical in nature

– User interface• How the people interact with the DSS• Data visualization is the key

– Text– Graphs– Charts

UserInterface

Analysis- Sensitivity Analysis- What-if Analysis- Goal-seeking Analysis-Data-driven tools -> Data mining -> OLAP*

Data Management

- Transactional Data- Data warehouse- Business partners data- Economic data

* OLAP: OnLine Analytical Processing

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DSS Analysis ToolsSimulation is used to examine proposed solutions

and their impact– Sensitivity analysis

– Determine how changes in one part of the model influence other parts of the model

– What-if analysis– Manipulate variables to see what would happen in given scenarios

– Goal-seeking analysis– Work backward from desired outcome

Determine monthly payment given various interest rates.

Works backward from a given monthly payment to determine various loans that would give that payment.

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Executive Information Systems Specialized DSS that supports senior level

executives within the organization Most EISs offer the following capabilities:

Consolidation – involves the aggregation of information and features simple roll-ups to complex groupings of interrelated information

Drill-down – enables users to get details, and details of details, of information

Slice-and-dice – looks at information from different perspectives

Digital dashboards are common features

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Artificial Intelligence (AI) systemsCommon categories of AI systems:

1. Expert system – computerized advisory programs that imitate the reasoning processes of experts in solving difficult problems

2. Neural Network – attempts to emulate the way the human brain works

– Analyses large quantities of info to establish patterns and characteristics in situations where logic or rules are unknown

– Uses Fuzzy logic – a mathematical method of handling imprecise or subjective information

3. Genetic algorithm – an artificial intelligent system that mimics the evolutionary, survival-of-the-fittest process to generate increasingly better solutions to a problem

4. Intelligent agent – special-purposed knowledge-based information system that accomplishes specific tasks on behalf of its users

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Expert SystemsArtificial Intelligence systems that codify human

expertise in a computer system– Main goal is to transfer knowledge from one person to

another– Wide range of subject areas

• Medical diagnosis• Computer purchasing• Finance

– Knowledge engineer elicits the expertise from the expert and encodes it in the expert system

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Expert Systems Components Knowledge base: database of the expertise, often in IF THEN rules. Inference engine: derives recommendations from knowledge base and problem-specific

data User interface: controls the dialog between the user and the system Explanation system: Explain the how and why of recommendations

Knowledgebase

Domain Expert

Knowledge Engineer

Expertise

ExplanationSystem

InferenceEngine

UserInterface

User

System Engineer

Encoded expertise

IFfamily is albatross ANDcolor is whiteTHENbird is laysan albatross.

IFfamily is albatross ANDcolor is darkTHENbird is black footed albatross

Example of rules

- Knowledge engineer codify the human expert’s expertise into the systems’ knowledge base.- System engineer is the IT professional who develop the user interface, the inference engine, and the explanation system.

Database & Data Warehouse

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Basic Concepts of Database systems

Table– Two-dimensional structure composed of rows and columns

Field– Like a column in a spreadsheet

Field name– Like a column name in a spreadsheet– Examples: AccountID, Customer, Type, Balance

Field values– Actual data for the field

Record– Set of fields that describe an entity (a person, an account, etc.)

Primary key – A field, or group of fields, that uniquely identifies a record

AccountID Customer Type Balance

660001 John Smith Checking $120.00

660002 Linda Martin Saving $9450.00

660003 Paul Graham Checking $3400.00

Accounts table

Each table has:

Fields Records 1 Primary key

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Basic Concepts in Data Management A Primary key could be a single field like in these tables

AccountID Customer Type Balance

660001 John Smith Checking $120.00

660002 Linda Martin Saving $9450.00

660003 Paul Graham Checking $3400.00

Primary key

Primary key could be a composite key, i.e. multiple fields

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Traditional File SystemsSystem of files that store groups of records used by a

particular software applicationSimple but with a cost

– Inability to share data

– Inadequate security

– Difficulties in maintenance and expansion

– Allows data duplication (e.g. redundancy)

Application 1

Program 1

File 1

File 2

File 3

Program 2

File 1

File 2

File 3

Application 2

Program 1

File 1

File 2

File 3

Program 2

File 1

File 2

File 3

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Traditional File System AnomaliesInsertion anomaly

– Data needs to be entered more than once if located in multiple file systems

Modification anomaly– Redundant data in separate file systems– Inconsistent data in your system

Deletion anomaly– Failure to simultaneously delete all copies of

redundant data– Deletion of critical data

Database AdvantagesDatabase advantages from a business

perspective include– Ease of data insertion

• Example: can insert a new address once; and the address is updated in all forms, reports, etc.

– Increased flexibility• Handling changes quickly and easily

– Increased scalability and performance• Scalability: how the DB can adapt to increased demand

– Reduced information redundancy & inconsistency– Increased information integrity (quality)

• Can’t delete a record if related info is used in other container

– Increased information security

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Types of DBMSsDesktop

– Designed to run on desktop computers

– Used by individuals or small businesses

– Requires little or no formal training

– Does not have all the capabilities of larger DBMSs

– Examples: Microsoft Access, FileMaker

Desktop

Server / Enterprise

Handheld

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Types of DBMSs (Cont.)

Server / Enterprise– Designed for managing larger and complex databases by

large organizations– Typically operate in a client/server setup– Either centralized or distributed

• Centralized – all data on one server– Easy to maintain– Prone to run slowly when many simultaneous users– No access if the one server goes down

• Distributed – each location has part of the database– Very complex database administration– Usually faster than centralized– If one server crashes, others can still continue to operate.

– Examples: Oracle Enterprise, DB2, Microsoft SQL Server

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Types of DBMSs (Cont.)

Handheld– Designed to run on handheld devices– Less complex and have less capabilities than

Desktop or Server DBMSs– Example: Oracle Database Lite, IBM’s DB2

Everywhere.

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DBMS FunctionsCreate database structure (tables, relationships, schema,

etc.)Transform data into information (reports, ..)Provide user with different logical views of actual

database contentProvide security: password authentication, access control

– DBMSs control who can add, view, change, or delete data in the database

ID Name Amt01 John 23.0002 Linda 3.0003 Paul 53.00

Physical viewID Name02 Linda

Name Amt Paul 53.00

ID Name Amt01 John 23.0002 Linda 3.00

Logical views

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DBMS Functions (cont.)

Allowing multi-user access with control– Control concurrency of access to data

– Prevent one user from accessing data that has not been completely updated

• When selling tickets online, Ticketmaster allows you to hold a ticket for only 2 minutes to make your purchase decision, then the ticket is released to sell to someone else – that is concurrency control

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Database Models

Database model = a representation of the relationship between structures (e.g. tables) in a database

Common database models– Flat file model

– Relational model (the most common, today)

– Object-oriented database model

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Flat File Database model Stores data in basic table structures No relationship between tables Used on PDAs for address book

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Relational Database Model Multiple two-dimensional tables related by common fields Uses controlled redundancy to create fields that provide

linkage relationships between tables in the database– These fields are called foreign keys – the secret to a

relational database– A foreign key is a field, or group of fields, in one table

that is the primary key of another table Handles One-to-Many and One-to-One

relationships

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Object-Oriented Database model

Needed for multimedia applications that manage images, voice, videos, graphics, etc.

Used in conjunction with Object-oriented programming languages

Slower compared to relational DBMS for processing large volume of transactions

Hybrid object-relational Databases are emerging

Data WarehouseA logical collection of information gathered

from many different operational databases Supports business analysis activities and

decision-making tasksThe primary purpose of a data warehouse

is to aggregate information throughout an organization into a single repository for decision-making purposes

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Data Warehouse Fundamentals Many organizations need internal, external, current, and

historical data Data Warehouse are designed to, typically, store and

manage data from operational transaction systems, Web site transactions, external sources, etc.

Multidimensional Analysis Data mining – the process of analyzing data to extract

information not offered by the raw data alone Data-mining tools use a variety of techniques (fuzzy-

logic, neural networks, intelligent agents) in order to find patterns and relationships in large volumes of data and infer rules that predict future behavior and guide decision

making

Other analytical tools: query tools, statistical tools, etc. used to Analyze data, determine relationships, and test hypotheses

about the data

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Data Warehouse Fundamentals

Extraction, transformation, and loading (ETL) – a process that extracts information from internal and external databases, transforms the information using a common set of enterprise definitions, and loads the information into a data warehouse.

Information Cleansing or Scrubbing Organizations must maintain high-quality

data in the data warehouseInformation cleansing or scrubbing

– a process that weeds out and fixes or discards inconsistent, incorrect, or incomplete information

– first, occurs during ETL. Then, when the data is in the Data Warehouse using Information cleansing or scrubbing tools.

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Data Mart

Subset of data warehouses that is highly focused and isolated for a specific population of users

Example: Marketing data mart, Sales data mart, etc.

Database vs. Data WarehouseDatabases contain information in a series

of two-dimensional tablesIn a Data Warehouse and data mart,

information is multidimensional, it contains layers of columns and rows

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Date

Produ

ct

Cou

ntr

y

sum

sum TV

VCRPC

1Qtr 2Qtr 3Qtr 4Qtr

U.S.A

Canada

Mexico

sum

Total annual salesof TV in U.S.A.

Networking & Telecom

Why Networking ?• Resource sharing

– Sharing hardware (printers, processors, etc.)– Sharing software (programs, data files)

• High reliability– Can set automatic backup of programs and data at

different locations– Fault tolerance (if one server is down, others can provide

service. If a disk fails, data available through mirror or RAID-3 disks)

• Possible cost savings

• Communication tool– Internal email service– Remote Access service 39

Computer Network

• An interconnection of computers and computing equipment using either wires or wireless transmission media over small or large geographical distances.

“Connect to GHI”ABC

DEF GHI

JKLMNO

Once connected to the network, the computer (or another device) becomes a network node

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Network scope• Local area network (LAN): computer network

where the nodes are all in close proximity spanning a room, building, or campus

• Metropolitan area network (MAN): network that serves an area of 3 to 30 miles - approximately the area of a typical city.

• Wide area network (WAN): a large network that encompasses parts of states, multiple states, countries, and the world

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Transmission Media• Physical media

– Transmission media used to physically connect nodes to the network

– Transmits electrical or optical signals– Could be copper wire or fiber optic cable

Physical

Wireless

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Transmission Media (Continued)

• Twisted PairCategory Use Signal Data rate Distance Problem

Category 1 Telephone Analog/Digital <100Kbps 3-4 miles Security, noise

Category 2 T1, ISDN Digital <2 Mbps 3-4 miles Security, noise

Category 3 LANs Digital 10 Mbps 100 m Security, noise

Category 4 LANs Digital 20 Mbps 100 m Security, noise

Category 5 LANs Digital 100 Mhz 100 m Security, noise

Category 6 LANs Digital 250 Mhz 100 m Security, noise

Category 7 LANs Digital 600 Mhz 100 m Security, noise

• Fiber optic– Thin glass fibers surrounded by coating– Uses laser or light for data transmission– Very fast (10+ Gbps, 100 miles without any repeater)– Very secure

SourcePhoto diode(LED or LD)

DestinationPhoto receptor(LED or LD)Fiber optic cable 43

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Wireless transmission media

• Infrared light– Has many of the same characteristics as

visible light– Travels in straight lines– Cannot penetrate solid objects

• Radio waves– Travel in straight lines– Can penetrate through nonmetallic objects– Can travel long distances

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Wireless Media issues• Use electromagnetic waves or electromagnetic radiation for data

transmission• Propagation through space, and indirectly, through solid objects• Many problems:

Laptop Comm. Tower

ShadowZone

Radio waves tend to bounce off objects. Receiver can receive 2 or more signals.

Thick objects can block the direct path. So, Receiver will be in a

Shadow zone where it cannot well receive.

Insecure: Easier to

“intercept” messages

ElectromagneticInterference (EMI) from

Other stations,Microwave ovens, etc

MultipathInterference

+ Much more attenuation than physical transmission media

Computing Equipment• Network interface card (NIC): Device that

– provides a computer with unique address– Converts data into signal for transmission

• Hub / Switch: Central collection point for transmission media that interconnect computers

• Modem– Converts digital data into analog signal and back again

• Router – special hardware that determines optimal routing path for

data packets – Usually used to connect a LAN to a WAN

• Bridge– Forwards messages between LANs 46

1.Station A transmits

to the Hub

2.Hub broadcasts

to all stations

Station C must wait,or its signal willcollide with Station A'ssignal

StationA

StationB

StationC

StationA

StationB

StationC

Hub operation

Hubs split available bandwidth among computers, i.e. with a 100 Mbps hub, the network speed will be 100 Mbps / n (where n is the number of computers)Active hubs include repeater capabilities for regenerating signals.Passive hubs don't regenerate signals. Limited to a 30meter distance apart from computers.

(Except sending station)

Switch operation

StationC

StationD

Switch

StationB

Station ATransmits

to Station C

Switch SendsSignal out aSingle Port

1 62 3 4 5

StationA

Station BTransmits

Simultaneouslyto Station D

Switches send out a single port: destination port.Most switches can efficiently handle simultaneous transmissionsSwitches provide a full bandwidth to all connected computers.

Switching tableMAC Address PortA1-44-D55-1F-AA-4C 1 (Station A)B2-CD-13-5B-E4-65 2 (Station B)C3-2D-55-3B-A9-4F 5 (Station C) ; ;

Network Software• Network operating system

– Used on servers– Used for managing network resources– Examples: Novell NetWare, Windows Server

2008

• Workstation operating system– Used on client PCs– Used to manage local resources & access

network resources

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Protocols• An agreed upon set of rules that govern

communication in a network

• All computers on a network must use same protocol for effective communication

• Example of protocols: • Ethernet (for communication in a LAN)

• Token Ring (for communication in a LAN)

• TCP/IP suite (for communication in a LAN and the Internet)Computer 1

Rules for Task 1

Rules for Task 2

Rules for Task 3

Rules for Task 4

Rules for Task 5

Computer 2

Rules for Task 1

Rules for Task 2

Rules for Task 3

Rules for Task 4

Rules for Task 5

Network Topologies

• The configurations of network components– How physically the network looks like– How logically data is transferred on the network

• Types of network topologies:– Bus– Star– Ring

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Bus Network Topology• Most simple network topology• All devices connected to a common central

cable called a “bus”• Inexpensive• If cable fails, the entire network will shut down

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Star Network Topology

• Centered around central device called a hub or a switch

• All network nodes connect to the hub/switch

• Easy to install and update

• If hub fails, network fails

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Ring Topology

• Node connected to a logical ring in a central device called MAU

• More reliable than bus or star– Only one node sends at a

time (no collisions)

• Expensive and limited speed

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Networks communication models and operation

• Define how the processing takes place on the network

• Define the roles of each participating computer

• Two primary models:– Client-server– Peer-to-peer (P2P)

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Client-server model• Computers are either clients or servers• Clients use services• Servers provide services

– File service– E-mail service– Printing service– Database service– Etc.

• Client software on client node cooperates with server software on server node– The WWW is the largest client/server network56

Client-server model• Collaboration between Client and Server program

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Client-server model• Division of Labor

– Client program handles lighter work, such as user interface chores and light processing chores

– Server program handles heavy work, such as database retrieval

Client Machine Server

Client ProgramServer

Program

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Peer-to-Peer network

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• No dedicated server• Computer are equal (peers)• Computers can all receive and provide service• Multiple P2P models over the years

– Pure P2P– P2P Viral network– P2P with index server

Pure P2P network

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• Each computer must have the appropriate type of protocol & software for interaction with others

• Each computer must have a network connection to others• Each computer can connect to any participating computer to get service (e.g.

download files)

• What can be the major issues associated with P2P networks?

Pure P2P viral network

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• Client connects to another client, which connects to several others, and so forth• When client first connects, it sends initiation msg to introduce itself via viral networking• Searches sent by a client are also passed to others through viral networking• When file is found, actual file downloads are done using direct (not viral) communication• Companies offering P2P viral networking service, put in place super clients that are always on with

permanent IP addresses

Client 1

Client 2 Client 3

Client 4

Client 5

P2P File download

Init or

search msg

Init or search msg

Init or search msg

Init or

search msg

Init or

search

msg

Note: Response to Init and Seach msg not shown

P2P using Index server

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• Most common type of P2P networking used in file sharing• Introduced by Napster (now an online music store after law suits)• Relies on an Index server

Client PC

NapsterIndexServer

1.Uploads ListOf Available

FilesWhen Connects

Client PC Client PC

2.Search Query

3.Response 4.

Large P2PDownload

File List

List ofAvailable Files

From AllCurrent Clients