ANALYSIS AND DESIGN OF INFORMATION SYSTEM

Investigation System Concept

System investigation here is done when there is or there is a gap in the difference (gap) between the purpose of the system and actual system conditions. For example, the system is to satisfy customers in terms of services company, but the system has a condition which can not satisfy customers, as early goals of the system is made, so that here the system is needed to improve the system of investigation that has been there.

There is a system of investigation here also be due to a detection of the problems that the report does not really real, such as:

• Too ideal destination

• Lack of resources and / or attitude

• Measurement system is less accurate

• System that is the purpose behind

• The difference between the ideal system and the system while

Problem solving:

• Decompose the system is running.

• Where is the investigation carried out here in detail

• Getting a consensus that the ideal system

• Developed several alternative

• Selecting the best alternative

Constraint in Investigation System

When doing investigation several constraints appear like:

• Time

• Cost

• Knowledge

• Politic

• Get involved

Recommendation

Result of investigation is one recommendation, one that one of it is as follows:

• Don't take action whatever since undiscovered problem.

• Doing preserve system for problem what do little.

• Increasing ability or user skill at deep going or utilizes information system.

• Regarding for system modification totally, so needs thinking to substitute it with system a new one.

• Placing happening problem into systems developmental plan which shortly be done.

Investigation Tactics

Why need the tactics?

• Finding all problem

• Knowing cause of problem appearance

• Determining correct solution

Investigation tactics Is conducted so that all system element can accept the solution offer without bothering their activity

Some tactics which can be conducted:

• Listening opinion of system perpetrator

• Don’T give the resolving early

• Comparing story some people of system perpetrator to same case

• Paying attention to problem of inconsistent logical

Investigation Technique

1. Direct:

   • Questioner

   • Question and Answer

   • Monitoring

2. Non-direct:

• Current procedure

• Learn the document

• Sample

• Tabular

Analysis Requirement

Stage of intensive interaction between the systems analyst with the end user where the system shows the development team expertise to get feedback and trust so that the user get a good participation.

Four Purpose That Want Achieved:

• Explain the complete system

• Information system that describes the ideal

• Bringing information system to the ideal conditions at this time with attention to the constraints of resources

• Provide encouragement to the confidence in the system development

Method

• FAQ

• Quisioner

• Observation

• Procedure analysis

• Observation document

Constraints Of Resource

• Time

• Money

• Expertise

• Technology

• External factors

Analysis Document Requirement

• Landing analysis: Relationships with end users, the observation process, problems in data collection.

• The user needs: The need actual, reporting requirements, training needs and the influence of the new system.

• System constraints: Explain the constraints of time and cost, expertise, technology, and external factors.

• Documents such as data collection instruments, statistical consensus, the logical flow of data and physical, data elements in the initial data dictionary.

Generating Systems Alternatives

How the way to bring closer system condition in now with ideal system condi
tion ?

• Make alternative for solving the information system problem.

• The best alternative applied wisely.

Strategy choise

• Distributed versus centralized processing
  Alteration information decision of centralized data processing to decen-
  tralized end user responsibility center.

• Integrated versus dispersed database
  Designing system must consider the data, which it to enter in database &
  in file.

• Surround Strategy of System Development
  The circle is important strategy in the way of taking company because in-
  formation system from other company maybe is differing.

Tactics choise : before designing operational selection.

Designing operational selection.
Designing selection can be grouped into :
1. Input
Online Vs Off Line Data Entry
- Keyed Vs Machine Readable Data Entry
- Centralized Vs Decentralized Data Entry
2. Processing
- Batch Vs Realtime record update
- Sequential Vs Direct Access to records
- Single Vs Multiple User update of records
3. Output
- Traditional Vs Turn Around Documents
- Structured Vs Inquiry based reports

Selecting the Proper System

• Equal tactic: equivalent system based on cost and profit relatively. There is 3 system, A called more excellent with other system if:

  • A have low cost then B and their profit same.

  • A have low cost then B and A produce profit more than B.

  • A and B have same cost but produce of profit A more than B.

• Several comparative method system

• Break Even point analysis

• Payback period

• Discounted payback period

• Internal rate of return

• Cost category

  • Hardware

  • Software

  • People

  • Suppliers

  • Telecommunications

  • Physical sites

• Cost details

Equal system information cost by means of life system, analyst projection several cost change for future and 3 cost model information system that is Linear, Exponential and Step Function.

• Information system cost happen in one time and be able happen continuous.

  • Information system cost happening in one time that is on-time cost and development cost while system development consist.

  • Information system cost happening continuous there are recurring cost with operational cost while cost happen at information system operated every day.

Factor Of Information System

• Reduce errors

• Reduce the time to fix errors

• Reducing the response time from the workstation alternative

• Accelerating the provision of information

• Increase the security system

• Have active update source record

• Increase user satisfaction

Presenting Study Of System

• To do presentation with short time.

• Lessen technique explanation with detail

• If using model use appliance assist for example laptop so that more informative.

Decision Drawns Out Or Not

• If firm decides to develop system therefore information department will do succeeding process which is System Design Process.

• If contrariwise therefore System Development Life Cycle (SDLC) will be discontinued.

• Oft will find problem with study system and usually top management will ask for to do its reworking to study system.

• Model will word some part step which and sometimes information department will make repeat decision step before word study system.

• With alternative, decision for repeat one SDLC'S step in advance or not been called Go – No. –Go Decision.

THE PURPOSE OF SYSTEM DEVELOPMENT PUBLIC.

The important.of systems development is compiling a new system to replace system old ones as a whole or improve;repair system which have there. The system old ones require to improve because, existence of problems - problems that appear in system old ones. Problems of arising out such of.
a. Annoyance in growth’s system of organization
The example of annoyance in growth’s system of organization, insincerity.and mistake which intended, its efficiency of operation not and not obey of policy of management.
b.. Growth of organization.
c. For reach the opportunitys ( opportunities).
d Existence of instructions ( directives).
There are the purposes of development of information system is
a.. Solving problems.
b. Reach for opportunitys.
c. Fulfill the instruction that given.
There are the expectations of organization after executing the information system
a. Performance ( performance)
Measured to use and throughput of response time. The improvement of performance in a new system make the system will be effective. Performance can be measurement from throughput and response time where throughput is amount of work of which can done certain in a moment and response time is time mean which delay between two transactions.
b. Information ( information)
The improvement of information quality which presented.
c. Economy ( economic)
Increase the benefit of vs decreasing cost.
d. Control ( operation)
The improvement of control, detecting and improve;the mistake. To detection and repairing some faults and insincerity which possible happened.
e. Efficiency ( efficiency)
The improvement of operating efficiency. Efficiency related with how to use resource without doing extravagance.
f. Services ( service)
Increase the service of system.
There are some principles of system development of information
a.. System for the management.
b. System is a big invesment
Investigation of all alternative (minimizing missing cost opportunity) best investigation have to be valuable : analysis cost-benefit & analysis cost-effectivenes.
c. System need educated people
Not allowed education have to be formal.
d. Step work system cycle life development.
e.. System development [do] not have to numbering.
f. Don't fear to cancel project.
g. System documentation.
Three cycle live development of system are
Model of waterfall

Requirement à Analysis gathers the requirements for the system. This stage includes a detailed study of the business needs of the organization. Options for changing the business process may be considered. Design focuses on high level design like, what programs are needed and how are they going to interact, low-level design individual, interface design and data design. During these phases, the software's overall structure is defined. Analysis and Design are very crucial in the whole development cycle. Any glitch in the design phase could be very expensive to solve in the later stage of the software development. Much care is taken during this phase. The logical system of the product is developed in this phase.
Design à In system design functions and operations are described in detail, including screen layouts, business rules, process diagrams and other documentation. The output of this stage will describe the new system as a collection of modules or subsystems.
Implementation à In this phase the designs are translated into code. Computer programs are written using a conventional programming language or an application generator. Programming tools like Compilers, Interpreters and Debuggers are used to generate the code. Different high level programming languages like C, C++, Pascal and Java are used for coding. With respect to the type of application, the right programming language is chosen.
Testing à In this phase the system is tested. Normally programs are written as a series of individual modules, these subjects to separate and detailed test. The system is then tested as a whole. The separate modules are brought together and tested as a complete system. The system is tested to ensure that interfaces between modules work, the system works on the intended platform and with the expected volume of data (volume testing) and that the system does what the user requires (acceptance/beta testing).
Maintenance à tably the system will need maintenance. Software will definitely undergo change once it is delivered to the customer. There are many reasons for the change. Change could happen because of some unexpected input values into the system. In addition, the changes in the system could directly affect the software operations. The software should be developed to accommodate changes that could happen during the post implementation period.
Model iteratif


The challenge in iterative development is to make sure all the iterations are compatible. As each new iteration is approved, developers may employ a technique known as backwards engineering, which is a systematic review and check procedure to make sure each new iteration is compatible with previous ones. The advantage of using iterative development is that the end-user is involved in the development process. Instead of waiting until the application is a final product, when it may not be possible to make changes easily, problems are identified and solved at each stage of development. Iterative development is sometimes called circular or evolutionary development.
Model spiral

The new system requirements are defined in as much detail as possible. This usually involves interviewing a number of users representing all the external or internal users and other aspects of the existing system.
A preliminary design is created for the new system.
A first prototype of the new system is constructed from the preliminary design. This is usually a scaled-down system, and represents an approximation of the characteristics of the final product.
A second prototype is evolved by a fourfold procedure: (1) evaluating the first prototype in terms of its strengths, weaknesses, and risks; (2) defining the requirements of the second prototype; (3) planning and designing the second prototype; (4) constructing and testing the second prototype.
At the customer's option, the entire project can be aborted if the risk is deemed too great. Risk factors might involve development cost overruns, operating-cost miscalculation, or any other factor that could, in the customer's judgment, result in a less-than-satisfactory final product.
The existing prototype is evaluated in the same manner as was the previous prototype, and, if necessary, another prototype is developed from it according to the fourfold procedure outlined above.
The preceding steps are iterated until the customer is satisfied that the refined prototype represents the final product desired.
The final system is constructed, based on the refined prototype.
The final system is thoroughly evaluated and tested. Routine maintenance is carried out on a continuing basis to prevent large-scale failures and to minimize downtime.
There are the approve of development a system
a. Classic approach vs approach of structure.
classic approach
Steps in sdlc.
Do not involve consumer, for emphasizing the system analyst.
Problems: difficult development, expense of costly treatment, possibility of big mistake, efficacy less well guaranted, applying internal issue.
approach of structure
Consumer involve from early to determine the requirement of system.
Using tools-tools like data of flow diagram.
b. Approach of rasher of vs approach of system.
approach of rasher
IEmphasizing at an activity or application.
Heedless of entirety target.
approach of system
See system as one intact unity.
Emphasizing at goal achievement as a whole.
c. Approach of bottom-up vs approach of top-down.
approach of bottom-up
Started from level under that is operational.
Representing classic approach marking.
Recognized with term of data-analysis.
approach of top-down
Started from up level that is planning of strategy.
Representing marking approach of restructure.
Recognized also with decision-analysis.
d. Approach of vs whole system vs approach of moduler.
approach of whole system
Developing system at a time and totally.
Representing classic approach marking.
approach of moduler
Breaking complicated system become the parts of simple.
Developed system become timely, easy to to be comprehended and looked after v.representing marking approach of structure.
e. Approach of great loop approach vs expand.
approach of ( approach great-loop )
Developing system at a time use sophisticated technology.
High risk and finish many expense.
approach expand ( approach evolutionary)
Applying sophisticated technology for certain applications.
Developed to follow requirement.
Cost effective and can keep abreast of technology.
The meaning of methodology, method and algorithm
Methodologies is the methods which is used in science. Method is a way of systematic to do something. And Algorithm is procedure sequence to solve a problem.
There are the clarification of three classification of metodology development of system.
Decomposition functional.
Ephasizing resolving of system become subsistem. The example HPO,, stepwise refinement, refinement stepwise iterative, hiding information.
Data-oriented.
Emphasizing at processed data characteristic:
Oriented data-flow: modules according to data element type.
Oriented data-structure: input structure and of output.
Prescriptive
Usually provided by factory maker of software.
There are the appliance - appliance used to develop a system
In form of graph: hipo, sadt, jackson's diagram, and others.
appliance using schema
a Charting activity: depicting activity, example [of]: chart gant, flowchart, etc.
b Charting layout: depicting the place of system.
c Relationship charting personal: depicting personnel , example : chart organization, chart distribution working.
There are the technique - used technique in developing a system
a Management technique of project for schedule of project , example : cpm and of pert.
b Technique find fact to collect and determine data / fact :
1. Interview
2. Observation
c Technique analyse expense / benefit of cost-benefit and cost-effectiveness analysis.
d Technique to do the meeting.
e Inspection technique.
The difference of system’s analyst and a programer
A. System analyst: studying problems and determine requirement of system to identify resolving.
B. Programmer: writing program code pursuant the design made by analyst.
System analyst undertake to link difference of knowledge that happened between system’s analyst and system of programmer.
There are the knowledge that used an analyst system to influence a system:
a. Data-processing technology, and computer of programming.
b. Knowledge of business in general.
c Quantitative method: regretion, linear programming, etc.
d. Skill of trouble-shooting.
e. Skill of communications between personnel.
f. Skill to construct relation between personnel.