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Exam 2 Review
June 9, 2014
Info. Systems in OrganizationsDecision Making
3
IS & Hierarchical Organizational structure
• .
4
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
6
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.
Herbert Simon (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 decision-maker can solve the problem.– Within their scope of
influence?
• Fully define the problem by gathering more information about the problem.
Scan Environment forproblem to be solved
or decision to be made
Data source
Organizational IS
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
• Select the solution to implement.– More detailed analysis of selected solutions
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
– 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
33
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
41
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
44
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
45
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: Inverse Square law
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
• Network monitoring software– Packet sniffers – allow seeing data as it moves over
network– Keystroke monitors – allow seeing what users are typing
49
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
51
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
52
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
53
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
54
Network Architectures/Models
• Defines how the processing takes place on the network
• Two primary models– Client-server– Peer-to-peer (P2P)
55
Client-server model• Nodes are either clients or servers• Clients use services• Servers provide services
– File service– E-mail service– Printing service– Database service
• Client software on client node cooperates with server software on server node– The WWW is the largest client server application
56
Peer-to-Peer model
• All nodes on the network are equal.• Any node can be both a client and a server.
57
Security & Privacy
TCP/IP Packet• TCP/IP Packets or computer messages have two parts:
– Communications protocols– Actual message to be delivered
Source IP Address: 123.12.2.1Source Program: Web Browser 1234Destination IP Address: 139.67.14.54
Destination Program: Server Program 80Formatting scheme: ASCII
Source IP Address: 123.12.2.1Source Program: Web Browser 1234Destination IP Address: 139.67.14.54
Destination Program: Server Program 80Formatting scheme: ASCII
Get index.phpFrom: server eiu.edu
Location: Home directory
Get index.phpFrom: server eiu.edu
Location: Home directory
Protocols tell the receiving computer: - Sender’s ID - How to read the message
Message to be delivered
59
Received: from hotmail.com (bay103-f21.bay103.hotmail.com [65.54.174.31]) by barracuda1.eiu.edu (Spam Firewall) with ESMTP id B10BA1F52DC for <[email protected]>; Wed, 18 Feb 2009 18:14:59 -0600 (CST)Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 18 Feb 2009 16:14:58 -0800Message-ID: <[email protected]>Received: from 65.54.174.200 by by103fd.bay103.hotmail.msn.com with HTTP; Thu, 19 Feb 2009 00:14:58 GMTX-Originating-IP: [192.30.202.14]X-Originating-Email: [[email protected]]X-Sender: [email protected]: <10E30E5174081747AF9452F4411465410C5BB560@excma01.cmamdm.enterprise.corp>X-PH: V4.4@ux1From: <[email protected]>To: [email protected]: RE: FW: Same cell#Subject: RE: FW: Same cell#Date: Thu, 19 Feb 2009 00:14:58 +0000Mime-Version: 1.0Content-Type: text/plain; format=flowedX-OriginalArrivalTime: 19 Feb 2009 00:14:58.0614 (UTC) FILETIME=[DCA31D60:01C62D0D]X-Virus-Scanned: by Barracuda Spam Firewall at eiu.eduX-Barracuda-Spam-Score: 0.00
Hi,
I just wanted to let you know that I have received the packet you sent. 60
Attack strategy• Scanning
– Ping messages (To know if a potential target exist, is connected to the network, and is responsive)
– Supervisory messages (To know if victim available)– Tracert, Traceroute (to know about the route that leads to target)– Check the Internet (e.g. www.cert.org) for latest systems
vulnerabilities
• Use Brute Force attack or Dictionary attack– Trying different usernames and passwords in an attempt to
“break” a password and gain an unauthorized access.
• Use Social engineering strategy to get other information• By tricking employees to provide passwords, keys and other info. over
the telephone• By phishing i.e. misleading people to provide confidential info through
emails, fake websites, etc.
61
Major security threats
• Denial of Service (DoS) attacks• The attacker makes a target (usually a server)
crash in order to deny service to legitimate users
• Content attack• Sending messages with illicit or malicious content
• System intrusion• Getting unauthorized access to a network
62
Single message attacks: Ping of Death
• Ping of Death attacks take advantage of– Some operating systems’ inability to handle packets larger
than 65 536 bytes
• Attacker sends request messages that are larger than 65,536 bytes (i.e. oversized packets)
• Most operating systems have been fixed to prevent this type of attack from occurring.– But attacks occurred recently on Win Server 2003 systems
63
Defense against DoS attacks• Most DoS attack messages
– Include protocol settings with fake IP addresses or program numbers that do not match the type of message
Defense systems for protecting against DoS attacks are designed to check messages’ protocols part for fake or
inconsistent settings. Could be Packet Firewalls
Spoofing: using fake source IP address
Program number not consistent with the message supposed to be delivered.
Source IP Address: 10.1.2.1Source Program: Web Browser 1234Destination IP Address: 139.67.14.54
Destination Program: Server Program 80Formatting scheme: ASCII
Source IP Address: 10.1.2.1Source Program: Web Browser 1234Destination IP Address: 139.67.14.54
Destination Program: Server Program 80Formatting scheme: ASCII
Get index.phpFrom: server eiu.edu
Location: Home directory
Get index.phpFrom: server eiu.edu
Location: Home directory
64
Content attacks• Incoming messages with:
– Malicious content (or malware)• Viruses (infect files on a single computer)• Worms (Propagate across system by themselves)• Trojan horses (programs that appear to be benign, but do
damage or take control of a target computer)
– Illicit content• Pornography• Sexually or racially harassing e-mails• Spams (unsolicited commercial e-mails)
Q: Besides through emails, how can a computer system be a victim of a virus, worm, or Trojan horse attack? 65
Trojan horse• A computer program
– That appears as a useful program like a game, a screen saver, etc.
– But, is really a program designed to do damage or to open the door for a hacker to take control of the host computer
• When executed, a Trojan horse could– Format disks– Delete files– Allow a remote computer to take control of the host
computer. This kind of Trojan is called Back Door.• NetBus and SubSeven used to be attackers’
favorite programs for target remote control66
Open Mail Server
• Most content attack messages are sent through Open Mail Servers– Improperly configured Mail Servers that accept fake outgoing email
addresses)
Protection against content attacks• Antivirus controls
– PC-based antivirus control– Network antivirus control
• Application Firewalls– Catch every incoming message to check for illicit content in
the Message part– If illicit content detected, message is blocked
ApplicationFirewall
Attacker Target
Legitimate Message Checked Message
Illicit Message
Protocol Part Message
68
System Intrusion• System intrusion: Gaining unauthorized access to a
computer system by an intruder• A hacker is an intruder who breaks into a computer
system without authorization.• [supposedly] Not causing damage• [supposedly] Not stealing information
• A cracker is an intruder who breaks into a computer system to cause damage and/or to steal information
• Script kiddies are young people with little programming skills who use publicly available software to breach into systems
69See Hacker vs Cracker controversy at http://en.wikipedia.org/wiki/Hacker_definition_controversy#Hacker_definition_controversy
