computers in management 1

7/28/2019 computers in management 1

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VIGIN VARKEYS2 IEMVJCET


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1. Hardware provides basic computing resources(CPU, I/O devices).

2. Operating system controls and coordinates the useof the hardware among the various applicationprograms for the various users.

3. Applications programs are used to solve thecomputing problems of the users ( business programs,

video games).4. Users (people, machines).


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A program that acts as an intermediary between auser of a computer and the computer hardware.

Computer systems typically contain:Hardware and Software


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Hardware - electronic, mechanical, opticaldevices

Software programs Without support software, the computer is of

little use.. when the computer is on, OS will first load

into the main memory Operating system goals:

Execute user programs and make solving userproblems easier.

Make the computer system convenient to use.


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Operating

System

Device configuration

Controls peripheral devices connected to the computer

File management

Transfers files between main memory and secondarystorage, manages file folders, allocates the secondary

storage space, and provides file protection and

recovery

Memory management

Allocates the use of random access memory (RAM) torequesting processes

Interface platform

Allows the computer to run other applications


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provide a background for users programsto execute

display and deal with errors when it

happens control the selection and operation of the

peripheral devices.

act as a communication link between userand hardware.

system protection


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to handle 2 or more programs at the sametime from a single user s perception CPU can only perform one task at a time, however,

it runs so fast that 2 or more jobs seem to execute

at the same time


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Through computer networking CPUshandles different jobs.

Job1

Job2

Job3

Job

4

Job1

Job2

Job3

Job4

CPU 1 CPU 2 CPU 1

time

time

without

multiprocessingwith multiprocessing


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a temporary storage area (buffers) to readdata from input device or send data to theoutput device.


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Spooling is the process of a sending data to atemporary storage area in the computer'smemory. This data may contain files orprocesses.

The most common type of spooling is printspooling, For example, when you print adocument from within an application, thedocument data is spooled to a temporary storagearea while the printer warms up. As soon as the

printer is ready to print the document, the data issent from the spool to the printer and thedocument is printed.
http://www.techterms.com/definition/memoryhttp://www.techterms.com/definition/filehttp://www.techterms.com/definition/processhttp://www.techterms.com/definition/processhttp://www.techterms.com/definition/filehttp://www.techterms.com/definition/processhttp://www.techterms.com/definition/applicationhttp://www.techterms.com/definition/applicationhttp://www.techterms.com/definition/applicationhttp://www.techterms.com/definition/processhttp://www.techterms.com/definition/filehttp://www.techterms.com/definition/memory


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Single User Operating System Multi-User Operating System

Multi-Tasking Operating System

Distributed Operating System Batch processing Operating System.

Real time processing Operating System.


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As the name implies, Single-user-operatingsystem is designed to manage the computerso that one user can effectively do one thingat a time.

for example: DOS


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Multi-user OS is that which support more thanone users at the same time. in these types of OSthere is a server and all the users are provideddifferent terminals. these terminals areconnected to the server.

A multi-user operating system differs from asingle-user system on a network in that eachuser is accessing the same OS at differentmachines.

for example, the OS may need to handle

numerous people attempting to use a singleprinter simultaneously. The system processes therequests and places the print jobs in a queuesequence.


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A multitasking OS allows you to run multipletasks "simultaneously". They do not actually runat the same time, since there is only one CPU.

Usually CPU process only one task at a time but

the switching is so fast that it looks like CPU isexecuting multiple processes at a time.

the concept behind this is timesharing...operating system divides cpu timeamong various tasks but this time is very

small(nanosecond) that user feel that allprograms or tasks are runningsimultaneously......


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This type of operating system is seeneverywhere today and is the most commontype of OS, the Windows operating systemwould be an example.


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In a distributed system, software and datamaybe distributed around the system,programs and files maybe stored on differentstorage devices which are located in different

geographical locations and maybe accessedfrom different computer terminals.

This is not used in commonly.


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Jobs, together with input data, are fed intothe system in a batch.

The jobs are then run one after another.

No job can be started until previous job iscompleted


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Inputs immediately affect the outputs. Timingis critical e.g. Data from sensors is processed

immediately and provide outputs.(controlling of some nuclear power plants,chemical processing etc)

Timing is critical so the term refers Real timeprocessing Operating System anti-missile defense system

airplane landing control system


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efficient time spent to execute its programs should be short

small in size memory occupied should be as small as possible

reliable


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DESCRIPTION Simulation is a very powerful and widely used

management science technique for the

analysis and study of complex systems. This is normally done by developing a

simulation model. A simulation model usuallytakes the form of a set of assumptions about

the operation of the system, expressed asmathematical or logical relations between theobjects of interest in the system.


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What is simulation:The process of designing a mathematical or

logical model of a real-system and thenconducting computer-based experimentswith the model to describe, explain, andpredict the behavior of the real system.


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Simulation: Imitate the operations of afacility or process, usually via computer Whats being simulated is the system

To study system, often make

assumptions/approximations, both logical andmathematical, about how it works

These assumptions form a modelof the system

If model structure is simple enough, could use

mathematical methods to get exact information onquestions of interest analytical solution

K. Salah 24


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But most complex systems require modelsthat are also complex (to be valid) Must be studied via simulation evaluate model

numerically and collect data to estimate model

characteristics Example:- Simulation Based Plant

Maintenance Planning

K. Salah 25


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Some (not all) application areas Designing and analyzing manufacturing systems Evaluating military weapons systems Designing and operating transportation systems

such as airports, freeways, ports, and subways

Determining ordering policies for an inventorysystem Reengineering of business processes

{Fundamental changes to people and culture,organizational structure, policies/procedures,

and technology} Evaluating designs for service organizations suchas call centers, fast-food restaurants, hospitals,and post offices

K. Salah 27


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Many a times, the first simulation study isconducted by an external consultant in partbecause in-house staff is not familiar with thetechnique, and the staff is busy with every

day tasks. Unrealistic expectations from management

may result in simulation modeling beingconsidered as an empty promise tool.

Here we discuss how these challengespresent themselves and how they can beaddressed.


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Simulation Can: Measure Time in the system.

Measure Worker / machine utilization. Evaluate Changes to system inputs / resources

such as rate of arrival, rate of service.

Number of trucks available to move material fromone work station to another.

Simulation Cannot: It cannot give accurate results if the inputs are

inaccurate. It cannot solve problems; it can only provide

information from which solutions can beinferred.


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Advantages of Simulation Simulation Methods are usually easier to apply thananalytic methods.

Once a model is built, it can be used repeatedly forvarious analyses.

Simulation data is usually cheaper than datacoming from the real system.

Disadvantages of Simulation Simulation models may be costly to build.

Because of its statistical nature, many runs ofthe same model are necessary to achievereliable data.


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1.Total enterprise simulation These simulations involve modeling all or most

business functions (marketing, finance, operationsand R & D)

Its the first computerized business simulation. Total Enterprise simulations is divided into four

categories a)strategic management,b)business appreciationc)tactical management andd)totality simulations.


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These simulations cover the strategic management of

business. They may be run in a single session, spread over a course or

run on a spare time basis over several months.

Decisions cover marketing, finance, operations and productdesign and development.

To constrain complexity (and so duration) the tacticaloperation of the business (scheduling, material supply,distribution, etc.) is often done automatically by thesimulation model and so few or no decisions are made inthese areas.

these simulations are most appropriate for middle to seniormanagement development.


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These simulations are designed to show businesspeople how a business operates, develop business

acumen and basic financial knowledge.

Besides running as a single session, they can be

spread throughout a course, with one or moreperiods simulated each day.

These simulations are designed for junior tomiddle management, management trainees,

supervisors and functional specialists.


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These simulations cover the tactical managementof a business.

In contrast with strategic simulations that focus onthe external environment, these concentrate on the

internal management of the business. The simulation model is usually complex,

especially concerning factory and financialmeasures of the efficient operation of the business.


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It is used to describe those simulations thatattempt to replicate, in detail, the entire operationof a "real"business.

They combine the characteristics of strategy and

tactical simulations. complexity means that they take considerable time

to run and their scope may mean that they lack thefocus necessary for efficient use of learners time.


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These simulations focus on a specific functionalarea (sales, marketing, operations etc.)

These simulations are complex and usually last aday or more. Multiple decisions are made each

period but, unlike most other simulations, theseare of differing level of importance.

some decisions are of strategic importance, someof tactical importance and some are operational

necessities.


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These simulations focus on specific business issuesand concepts

These are short, two to four hour, simulationswhere groups of learners enter decisions into their

own computer, receive and analyse results. These are used to reinforce a topic, test

participants' understanding and provide a change

of pace.


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These involve the preparation of a business planusing a "What-If" model

Planning simulations are of particular use wheremanagers need to understand the business

implications of the topic. Planning simulations can be at a Strategic, Tactical

or Operational Level. Strategic planning simulationsinvolve learners preparing a plan covering severalyears. Tactical planning simulations involvelearners preparing a plan for the next yearsoperation on, typically, a month-by-month.


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These are simulations that involve the practical useof mathematical techniques such as statisticalforecasting, inventory planning, analysis of sales

performance etc.

A process simulation involves taking different setsof data through a business process to findpatterns, discuss implications and produce

forecasts or outcomes.


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Introduction The use of simulation is as old as the practice of

engineering itself, what has been very useful is the useof the computer to assist one in the analysis of largecomplex engineering and scientific problems.

Lately the advent of special high level computersoftware packages has made the use of the computereven easier and has increased the productivity of thescientists and engineers that use these tools.

Many of these software tools were very specialized andapplied to a narrow subject field. They are quite useful,however, it is very difficult to apply them to anothersimilar area.


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The latest development is the appearance ofseveral general purpose high level softwarepackages that are able to be applied to anyproblem of mathematical modeling that containsnon-linear, non-homogeneous, simultaneous,

high order, ordinary and parabolic partial,differential equations with associated algebraicequations and discontinuities.

Computer Simulation can be used to represent ingreat detail the performance of real world

systems which are often very complex (e.g. spacecraft, control systems, mechanical and electricalsystems, etc.).


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High-level continuous systems simulationlanguages are application oriented softwaresystems designed to assist Engineers andScientist to mathematically model and

analyze the behavior of piecewise-continuoussystems described by differential equations.


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Introduction 44

Assuming Simulation is the appropriate

means, three alternatives exist:

1. Build Model in a General Purpose

Language

2. Build Model in a General SimulationLanguage

3. Use a Special Purpose SimulationPackage


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Introduction 45

Advantages: Little or no additional software cost

Universally available (portable)

No additional training (Everybody knows(language X) ! )

Disadvantages: Every model starts from scratch

Very little reusable code

Long development cycle for each model Difficult verification phase


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Introduction 46

FORTRAN Probably more models than any other

language.PASCAL

Not as universal as FORTRANMODULA

Many improvements over PASCALADA

Department of Defense attempt at

standardizationC, C++ Object-oriented programming language


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Introduction 47

GPSS Block-structured Language Interpretive Execution FORTRAN-based (Help blocks) World-view:Transactions/Facilities

SIMSCRIPT II.5 English-like Problem Description Language Compiled Programs Complete language (no other underlying

language) World-view:Processes/ Resources/

Continuous


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Introduction 48

MODSIM III Modern Object-Oriented Language

Modularity Compiled Programs

Based on Modula2 (but compiles into C)

World-view:Processes

SIMULA ALGOL-based Problem Description Language

Compiled Programs World-view:Processes


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Introduction 49

SLAM Block-structured Language

Interpretive Execution

FORTRAN-based (and extended)

World-view:Network / event / continuous

CSIM process-oriented language

C-based(C++ based) World-view:Processes


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Introduction 50

Advantages Very quick development of complex models

Short learning cycle

No programming--minimal errors in usage

Disadvantages High cost of software

Limited scope of applicability

Limited flexibility (may not fit your specificapplication)


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Introduction 51

NETWORK II.5 Simulator for computer systems

OPNET

Simulator for communication networks,including wireless networks

COMNET III Simulator for communications networks

SIMFACTORY Simulator for manufacturing operations


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One of the great features of ESL is its ability tohandle discontinuities accurately. This was one ofthe European Space Agencies originalspecifications as when a thruster on a satellite isfired it must happen at the specified time and not

at the nearest integration interval. Examples of the use of ESL are the simulation ofa six legged robot combined with 3D animatedgraphics with a human controller in the loop andthe entire system running on multiple platformsin real time, as a training simulator for a processcontrol filtering system in a large water treatmentplant, and of course for satellite orbit analysis.


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The European Space Agency Simulationlanguage (ESL) was originally written to meetthe simulation requirements of the EuropeanSpace Agency. It started out as a general

purpose Continuous Systems SimulationLanguage (CSSL) and can still be used for thatpurpose.

It has a comprehensive supporting softwareenvironment and it can be used in any fieldwhere dynamic systems are studied and theirsimulations need to be used.


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CSSL-IV is a user-oriented software system designed tosupport analytical simulation. Availability, ease of use, andpowerful support tools allow CSSL-IV to be appliedeffectively to a broad range of technical problems.

Application areas range from aircraft flight dynamics,nuclear reactors, chemical processes, and physiological

dynamics to a wide variety of control systems. CSSL-IV provides access to many powerful programming

tools which speed simulation development andverification. Powerful systems-oriented functions coupledwith extensive man-machine inter-active capabilities allowthe user to concentrate on his/her simulation studies with

minimal burden from the computer system.


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ACSL (pronounced "axle") is an AdvancedContinuous Simulation Language. It wasintroduced 25 years ago, as a commerciallyavailable, modeling and simulation language

designed for simulating continuous systems.Based on the CSSL (Continuous SystemSimulation Language) standard, establishedby the Technical Committee of the Society for

Modeling and Computer SimulationInternational, [SCS].


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ACSL Sim was designed to help the engineer orscientist, mathematically model and analyze thebehavior of a continuous system described bytime-dependent, nonlinear differential equations

and/or transfer functions. Although continuous systems by their nature are

time-dependent, ACSL Sim lets you designate theindependent variable as something other than

time, such as distance or angle. This gives theuser the flexibility to model a multitude ofdynamic systems.

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computers in management 1