October 5, 2021

DECISION SUPPORT SYSTEM INTRODUCTION  Decision support system (DSS) in an outcome of management information system, providing support for management at operational control, management control, and strategic planning.  Management activity of each of these classes includes planning, control, and decision making.  A feature of the DSS that is currently receiving much publicity is computer graphics Graphs are good only in certain situations. However, in those situations some graphs are more effective than others.  The most recent embellishment of the DSS concept is the group decision support system (GDSS). The GDSS endeavours to improve communication among group members by providing simulating environment. DEFINATIONS  The term decision support system refers to a class of system which support the process of making decisions. The emphasis is on ‘support’ rather than on automation of decision.  DSS allows the decision maker to retrieve data and test alternative solution during the process of problem-solving. Keen and Scott Morton (1978) defined DSS as:  The impact is on decisions in which there is sufficient structure for computer and analytic aids to be of value but where manager’s judgement is essential;  The payoff is in extending the range and capability of manager’s decision processes to help them improve their effectiveness; and  The relevance for managers is the creation of a supportive tool, under their own control, which does not attempt to automate the decision process, predefine or objectives, or impose solution. However, this definition has certain limitations. In 1984, Freyenfeld (1984) proposed the following empirical definition of DSS based on discussions with some 30 supplier user and academic organisation:  “A Decision support system is an interactive data processing and display system which is used to assist in a concurrent decision making process, and which also confirm to following characteristics:  It is sufficiently user- friendly to used by decision makers(s) in person;  It display its information in a format and terminology which is familiar to the user(s);and  It is selective in its provision of information and avoids its user(s) in information overload.”  Another definition of a decision support system is: “A set of well-integrated, user-friendly, computer-based tools that combine data with various decision-making models—quantitative and qualitative—to solve semi –structured and unstructured problems.’’ EVOLUTION OF DSS:  The notion of decision support as a formal concept was coined by G. Anthony Gorry and Michael S. Scott Morton. They felt a need for a frame work to channel computer application towards management decision making and developed a grid, known as the Gorry and Scott Morton grid.  The grid each based on Simon’s concept of programmed and non-programmed decision and Robert N. Anthony’s management levels.  The decision types are described in terms of problems structure, ranging from structured to semi-structured to unstructured.  A fully structured problem is one in which the first three of Simon’s phases – intelligence, design and choice-are structured. The decisions are routine and straightforward. By following a setup pre-established step, a solution to the problem can be found. Such a problem does not require intuition or judgement. Therefore, the system returns the same solution every time.  An unstructured problem is one in which none of the three phases is structured. The decisions are unique and non–repetitive. Because they require intuition, experience judgement, there may be no one ‘best’ solution and solutions may differ from one decision maker to the other.  A semi-structured problem is one in which one or two of the phases are structured. The decision in this category fall somewhere between structured decisions, which are routine and repetitive, and unstructured decision, which are unique and non-repetitive.  Gorry and Scott Morton entered types of business problem into their grid. For example, accounts receivable is solved by managers on the operational-control level making structured decision. R&D planning is accomplished by strategic planning managers making unstructured decisions.  The horizontal dotted line through the middle of the grid is significant. Its separate the problem that had been successfully solved with computer assistance from those problems that had not been subjected to computer processing.  The upper area was named structured decision system and the lower area was named decision support systems.  DSS are especially useful for semi-structured problems where problem-solving is improved by interaction between the managers and the computer system.  The emphasis is on small, simple models which can easily be understood and used by the decision maker.  Examples of semi-structured decision are : planning a mix of investments for a portfolio, looking at the financial implication of various way of financing a short-term cash flow deficit, consideration of alternative production and pricing policies, assessing the impact of potential future changes in exogenous variables such as interest rates, analysis of the of the credit-worthiness of corporate clients, and assessing the likely impacts of departmental reorganization  OBJECTIVES OF DSS  Assist managers in making decisions to solve semi-structured problems.  Support the manager’s judgement rather try to replace it.  Improve the manager’s decision-making effectiveness rather than its efficiency.  These objectives correlate with three fundamental principles of the DSS concept-problem structure, decision support, and decision effectiveness.  CLASSIFICATION OF DSS  File Drawer Systems: This is a system which provides the user with organized information regarding specific demands. This system provides on-line information. This is very useful system for decision making.  Data Analysis Systems: These decision systems are based on comparative analysis and makes use of a formula. The cash flow analysis, inventory analysis and personnel inventory systems are examples of the analysis systems. This use of simple data processing tools and business rules are required to develop that system.  Information Analysis System: In this system the data is analysed and the information reports are generated. The decision makers use these reports for assessment of the situation for decision-making. The sales analysis, accounts receivables system, market research analysis are examples of such systems  Accounting Systems: These systems are not necessarily required for decision making

                                                    COMMUNICATION NETWORKS There are five types of communication networks: 1. Private Branch Exchanges (PBXs) 2. Integrated Services Digital Networks (ISDNs) 3. Local Area Networks (LANs) 4. Wide Area Networks (WANs) 5. Value Added Networks (VANs) Private Branch Exchanges (PBXs)  PBX (private branch exchange) is a telephone system within an enterprise that switches calls between enterprise users on local lines while allowing all users to share a certain number of external phone lines.  The main purpose of a PBX is to save the cost of requiring a line for each user to the telephone company’s central office.  The PBX is owned and operated by the enterprise rather than the telephone company (which may be a supplier or service provider).  Private branch exchanges used analog technology originally.  Today, PBXs use digital technology (digital signals are converted to analog for outside calls on the local loop using plain old telephone service (POTS ).  A PBX includes: • Telephone trunk (multiple phone) lines that terminate at the PBX • A computer with memory that manages the switching of the calls within the PBX and in and out of it. • The network of lines within the PBX. • A console or switchboard for a human operator (optional)  Integrated Services Digital Networks (ISDNs):  The ISDN is a digital communication network that uses the public telephone network and allows users to transmit data, voice, text, and video communication in digital form over telephone lines. So it is called a digital network.  It eliminates the need for a modem to convert analog signals into digital signals and vice versa.  It does not require any rewiring. It uses the coaxial or fiber optic cables,  It promotes uniformity and standardisation through a set of standard interfaces.  The basic building block of ISDN is a 64 kbps (thousands bits per second) channel, referred to as a B-channel.  Each B-channel is used to transmit user information.  Another channel called the D-channel, carries signaling and control information used to initiate, redirect, or terminate cells.  ISDN works basically on five principles:  Openness;  Modularity;  Communication based intelligence;  Network management and control;  Integrated products and services;  Openness: It means that all ISDN products will be standardized. This brings order and uniformity to the complex task of developing a network.  Modularity: It enables the organization to upgrade or replace any part in a network without replacing the entire network.  Communication based intelligence: It provides users with a way to configure their network connections to meet their requirements.  Network management and control: It is one of the complex and challenging tasks that information system managers face.  Integrated products and services: It allows the use of wide variety of products and services on the network such as voice networking, data networking, teleconferencing, etc. Recent computerized railway reservation network throughout the country is one of the examples of ISDN. Local Area Networks (LANS)  A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link.  It is connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building).  The server has applications and data storage that are shared in common by multiple computer users.  A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network).  Major local area network technologies are: Ethernet, Token Ring, and FDDI.  Ethernet is the most commonly used LAN technology.  A number of corporations use the Token Ring technology.  FDDI is sometimes used as a backbone LAN interconnecting Ethernet or Token Ring LANs.  Another LAN technology, ARCNET, once the most commonly installed LAN technology, is still used in the industrial automation industry.  A suite of application programs can be kept on the LAN server.  Users who need an application frequently can download it once and then run it from their local hard disk.  Users can order printing and other services as needed through applications run on the LAN server.  A user can share files with others at the LAN server; read and write access is maintained by a LAN administrator.  A LAN server may also be used as a Web server if safeguards are taken to secure internal applications and data from outside access. Wide Area Networks (WANS)  It is a collection of computers and network resources connected via a network over a geographic area.  Wide-Area Networks are commonly connected either through the Internet or special arrangements made with phone companies or other service providers.  A WAN is different from a MAN because of the distance between each of the networks. In a WAN, one network may be anywhere from several hundred miles away, to across the globe in a different country.  There are different types of set up a WAN are:-direct distance dialing (DDD), Wide area telephone service lines (WATS), leased lines and satellites.  Example:-banking networks, airline reservation systems and railway reservation systems. Value Added Networks (VANS)  The public data networks that add value to the basic communication services provided by common carriers by offering specialised services are termed as value added networks.  The specialized services include access to commercial databases and software, correction of transmission errors, providing compatibility between incompatible computers and terminals, Email, and video conferencing.  A subscriber to a VAN service pays monthly fee depending on its level of use.

DATA COMMUNICATIONS SYSTEM INTRODUCTION Data communication is the movement of data and information from one point to another point by means of electrical or electromagnetic devices, fibre-optic cables or microwave signals. TELECOMMUNICATIONS SYSTEM Telecommunications system has five components. These are 1. Sender: – input devices. 2. Channel & Media:-channel characteristics. • Transmission Speed. • Transmission Mode. • Transmission direction Media • Bounded. • Unbounded. 3. Hardware: – • Host Computer, • Front end Processor, • Modem, • Multiplexer, • Switch. • Bridge • Gateway • Bus. 4. Software:- • Access Control. • Transmission control. • Network control & Management. • Error detection & Correction. • Network Security. 5. Receiver:-Output Devices. 5.2.1. Telecommunications Channels A data communications channels is a path through a medium that data can take from sending stations to receiving stations. Characteristic of channels are: Transmission Speed: – It is the capacity of a telecommunication channel depending on the bandwidth. The greater bandwidth the greater amount of information transmitted over the channel. There are three types of bandwidth:-  Voice-band (300 bps to9600 bps),  Medium band (9600bps to 256000bps).  Broadband (256000bps to a very large number.) • Transmission Mode:-There are two types of transmission mode  Synchronous:-In this transmission a group of characters transmit at a time.  Asynchronous: – In this transmission one character transmit at a time. • Transmission direction:- It is the direction in which data is transmitted . There are three types of directions:  Simplex: – In this direction data communication devices that can either send or receive data, but can not do both.  Half duplex: – In this case two devices are send or received data, but not at a time.  Full duplex: – In this case two devices are send or received data at a time. Telecommunications Media There are two types of media over with data is transmitted. • Bounded media-The signals are confined to the medium. Ex-Twisted pair cable, fibre-optic cables, coaxial cable. • Unbounded media-The signal are not restricted to the medium. Ex-Microwaves. DATA COMMUNICATIONS HARDWARE  Host Computer:-The host performs the data processing for the network. The incoming messages are handled in the same manner as data received from any other type of input unit .After the processing, messages can be transmitted back to the front –end processor for routing.  Front-end processor:-The front-end processor is a minicomputer that acts as a buffer between the client device and the host computer. It increases the operating efficiency of the network by taking care of routine tasks such as coordinating peripherals and ensuring error free transmission.  Modem:-It stands for modulator-demodulator. It is used for Digital signals are converted into analog signals and vice-versa.  Multiplexer:-It is a device that permits the simultaneous sending and receiving of multiple messages over a signal channel. A multiplexer collects signals from several terminals and transmits them over a single channel.  Switch:-It is a device which is determines the data transmission path. Switches can control the transmission path across national or local networks.  Bridge and gateway:- • A bridge is a device that separates two or more network segments with in one logical network (e.g. a single IP-subnet). A bridge is usually placed between two separate groups

                                       Computer Application Software Application software assists in managing the organization’s physical and conceptual resources. There are two types of application software:  General purpose software  Dedicated software  General purpose software: it is designed for general applications such as payroll, inventory management, and accounting. Dedicated software is designed for specific application such as space shuttle.  Dedicated software: it includes specialized or customized applications designed for specific purposes. For example, logistic software helps firms handle the flow of goods and services from one location to another in order to cut costs, minimize inventory, and reduce the time it takes for goods, services, or information to reach their destination. ROLE OF SOFTWARE IN PROBLEM SOLVING  Software can play either a direct or an indirect role in problem solving. System software always plays in indirect role.  On the other hand, application software can play either a direct or an indirect role.  Most general business and industry specific packages are designed to play an indirect role by creating and maintaining the database that provides the basis for the information oriented subsystems.  Some industry specific packages go beyond data processing, providing components that directly contribute to problem solving.  Some organizational and personal productivity software only indirectly affects problem solving by simplifying the creation and transmission of data.  Other productivity software such as electronic spreadsheet, project management, forecasting, and statistical analysis packages provides direct support. CRITERIA FOR INVESTMENT IN HARDWARE AND SOFTWARE Investment in information systems and technologies include the acquisition of hardware, software, networks, and other computer related systems and technologies. Criteria for investment means the standards that an organization uses to make computer related investment decisions. Table lists some criteria that organization use to make information system and information technology investment decisions and the extent of use of each criterion.

COMPUTER SOFTWARE FOR INFORMATION SYSTEMS INTRODUCTION An information system builds both hardware and software are essential, systems being used in organisations are driven by a programs. A program is a set-up stepwise instruction given to a computer to accomplish various tasks. Programs are write software using special languages called programming languages. The process of writing program is referred to as programming. A set of program which instructs the hardware to perform a job is called as software. PROGRAMMING LANGUAGES There are two types of programming languages 1. Procedural language. 2. Non-procedural language. Procedural Language: A language, which explains stepwise sequential explanation to accomplish a given task, is called as procedural language. Non-Procedural Language: A non-procedural language focuses on what needs to be done, without specifying exactly how it should be done. FIRST GENERATION LANGUAGES (MACHINE LANGUAGE): The early computers were programmed in machine language or 1st generation language. A series of zeroes & ones then the CPU can interpret & execute. Machine language is important because it is the only language that the computer understands. Since machine language is difficult to use. Computer scientist  development, programming language which more closely resembled human communication. The program is written in the programmer’s language & is translate into the machine language before it is run. The program written by the programmer is known as the source program. The machine language is called as the object program. The system software translate the source program into the object program is called translator. SECOND GENERATION LANGUAGE (THE ASSEMBLERS): The 1st translator ware called assemblers. They permitted the programmer to code programs in assembly language or 2nd generation language. An assembly language mnemonic name for the operations that are to be performed symbolic names for the data that is processed. • Assembly language was a big improvement over machine language from the programmer’s point of view, but it had several draw backs. The assemble language programs are to be lengthy and ware difficult for programmers to read. THIRD GENERATION LANGUAGES (3 GLs) 3rd generation language can produce multiple object program instruction from a signal source program instruction. It means that programmers have to produce fewer lines of code in addition the syntax of 3rd generation language is more like the user’s language. Compiler produce a complete object program in one process then the object program is executed. An interpreter translates a source program instruction & executes it before going on the next instruction. • COBOL, FORTAN & PL/I are compiler language and basic program are interpreter languages.  FOURTH GENERATION LANGUAGES (4GLs) • 4th generation languages were developed in the 1970 to overcome the demands of procedural programming language. • 4th generation languages are non-procedural languages. If allow the programmer & users to instruct the computer in what to do rather than how to do it. • The term natural language is also used because the syntax of the 4th generation language can be very similar to our everyday speech. • (i) Data base query languages (ii) Modelling languages (iii) Very high level languages (iv)Graph generators (v)Report writers (vi)Application generators  Database query language:  It is shown here how a manager can use a data base query language that provides a special report from database contents without the need to code a program. The 4GL used in the example is FOCUS.  Modelling languages: A modelling language is especially designed to make the building of mathematical models easier than when a problem oriented language is used. One of the first modelling languages was GPSS (General purpose simulation system), developed by IBM in the early 1960s.The most popular ones that followed include DYNAMO, SLAM, SIMSCRIPT, GASP, MODEL, and IFPS.  Very high level language: The term very high level language is often used to describe a programming language, such as a APL, that offers succinctness and power over and above that of conventional languages.  Graph Generators: A graph generator is also called a graphics package, is used to display or print data in a variety of graphical forms.  Report writers: A report writer is specifically designed to prepare reports. The first example was RPG (Report program generator).COBOL has a report writer feature as do most of the database management systems.  Application Generators: An application generator produces an application program such as inventory or payroll, without programming .Examples are MANTIS and MARKV. • Maintain usage records  Operating system environment: There are two types of operating system environments:  Multiprogramming: It is a computing environment in which multiple users can run multiple programs on a single CPU computer at the same time. The CPU switches between programs, however at any given time is executing only one program.  Multiprocessing: it is system has a number of processors that process data and instructions, unlike systems that have only one CPU. It is ideally suited for complex and computationally intensive operations that require extensive processing. System support software: Programs which support the smooth execution of various programs and operations of a computer are called system support software. System support software includes utility programs, programming services software, database management systems, and security software and system documentation.  Utility programs These are among the most popular types of system support software. The perform tasks such as formatting disks, locating free space on a disk, retrieving lost or damaged files ,sorting and merging data, converting files from one format to another ,backing up important files and providing online help.  Programming services software It includes  Language translators  System loaders  Link editors,  System librarians.  Database management system It is a set of computer programs that enables a user to define, create access, manipulate, andoutput the information in records stored on a database.  Security software It protects a computer system and its files from unauthorized access. Examples of security software includes  Password programs  File protect programs  Encryption software.  System documentation It includes manual, flowcharts, reference, guides, and other operating instructions. System