iaAM's BLoG

NORMALIZATION EXERCISE

2009-05-03T06:16:00.001-07:00

NORMALIZATION IMPLEMENTATION

ER-DIAGRAM

1NF (FIRST NORMALIZATION)

Normal form if it met a 1NF table does not have many valuable attributes (multivalued attribute), attribute composite or a combination of data in the same domain.
Each attribute in the table must be atomic values (can not be divided-for more)

Picture :

Declaration :

NOPEG is the primary key of PEGAWAI
NOPRO is the primary key of PROYEK
NOBAG is the primary key of BAGIAN

2NF (SECOND NORMALIZATION)

Normal form 2NF met in a table if it meets the form of 1NF, and all the attributes than the primary key, have a full Functional Dependency on primary key
We can see at the table of Pegawai at 1ST NORMALIZATION has the transitive dependency between it's entities.

Transitive dependencies:
NoPeg → TglLah
TglLah → Umur

So the table of pegawai can be :

Picture :

A table does not meet 2NF, if there are attributes the need (Functional Dependency) are only partial (only depending on the part of the primary key)
If there are attributes that have no dependence on the primary key, then the attributes must be moved or removed

3NF(THIRD NORMALIZATION)

Normal form 3NF fulfilled if the form meets 2NF, and if there are no non-primary key attribute that has a dependence on non-primary key attributes of the other.

Example :

For each Functional Dependency with the notation X → A, then:

X must be a superkey at the table
Or A is a part of the primary key at the table

Picture :

Chapter6, Database Normalization

2009-04-25T23:46:00.000-07:00

Database Normalization

1. Database design process (review)

Gather user needs / business
Develop a needs-based ER Model user / business
Convert E-R model to the set of relations (tables)
Normalized relations, to remove anomalies
Implemented to create a database with a table for each relationship that is normalized

2. Database normalization definition

Normalization process is the establishment of the database structure so that most of the ambiguity can be removed.
Normalization stage, starting from the most mild (1NF) to most stringent (5NF)
Usually only up to the level of 3NF or BCNF because already sufficient to generate the table-a table of good quality.
Why do normalization?

Optimizing table structures
Increase speed
The income data is the same
More efficient in the use of storage media
Reduce redundancy
Avoid anomalies (insertion anomalies, deletion anomalies, update anomalies).
Improved data integrity

A table saying good (efficient) or if the normal 3 to meet the following criteria:

If there is decomposition (decomposition) table, it must be guaranteed safe its decomposition (Loss less-Join Decomposition). That is, after the table is described / being decomposition new tables, the tables can generate a new table with the same exact. Maintain dependence on the functional changes in data (Dependency preservation).
Does not violate Boyce-Code Normal Form (BCNF) if the three criteria (BCNF) can not be met, then at least the table does not violate the Normal Form of the third stage (3rd Normal Form / 3NF).

3. Functional Dependency

Functional Dependency describes a relationship attributes in relation an attribute said functionally dependant on the other, if we use the value attribute to determine the value of the other attributes. Symbol that is used to represent ïƒ functional dependency. ïƒ read determine the functional

Notation: A → B

A and B are attributes of a table.

A means of determining the functional B or B depends on A, if and only if there are 2 rows of data with the same value of A, then B is also the same value

Notation: A → B or A x → B

It is the opposite of the previous notation.

Example :

Functional Dependency:
NRP → Name

Value → , NRP

Non Functional Dependency:
NRP → subjects
Value → NRP

Functional Dependency of the table value

Nrp→ Name
Because for each value Nrp the same, then the value of the same name
Value → (subjects, NRP)
Because the value of attributes depending on the NRP and subjects together.
In another sense subjects for the NRP and the same, they also rated the same, because subjects and the NRP is a key (is unique).
Subjects → NRP
NRP → Value

4. First Normal Form - 1NF

A table on the form said to be normal if I did not reside in the unrealised form of a table, where there is a kind of field multiplication and field that allows a null (empty)
not allowed: Many attributes of value (Multivalued attributes). Attributes composite or a combination of both.
So: Price is the domain attribute must be atomic rates
Example :

Mahasiswa table :

The tables above do not meet the requirements 1NF

Decomposition becomes:

Mahasiswa table

Hobby table

5. Second Normal Form - 2NF

Normal form 2NF met in a table if it meets the form of 1NF, and all the attributes than the primary key, have a full Functional Dependency on primary key
A table does not meet 2NF, if there are attributes that its depend (Functional Dependency) are only partial (only depending on the part of the primary key)
If there are attributes that have no dependence on the primary key, then the attributes must be moved or removed
Functional dependence X → Y is full if it is said to Functional dependency X delete an attribute A from X means that Y is no longer dependent functional.
Functional dependence X → Y said partial if a delete attribute A from X means that Y is functionally dependent.
Relation scheme R in the form 2NF if every non-primary key attribute A € R depend on the full primary key functional R.
Example :

The following table meet 1NF,but not including 2NF

description :

Does not meet 2NF, because (NIM, KodeMk) is regarded as the primary key:
{NIM, KodeMk} : NamaMhs
{NIM, KodeMk} : Alamat
{NIM, KodeMk} : Matakuliah
{NIM, KodeMk} : Sks
{NIM, KodeMk} : NilaiHuruf
The Table needs to be some table decomposition eligible 2NF

Functional dependency :

{NIM, KodeMk} : NilaiHuruf (fd1)
NIM : {NamaMhs, Alamat} (fd2)
KodeMk : {Matakuliah, Sks} (fd3)

fd1 (NIM, KodeMk, NilaiHuruf) : Tabel Nilai
fd2 (NIM, NamaMhs, Alamat) : Tabel Mahasiswa
fd3 (KodeMk, Matakuliah, Sks) : Tabel MataKuliah

6.Third Normal Form - 3NF

Normal form 3NF fulfilled if the form meets 2NF, and if there are no non-primary key attribute that has a dependence on non-primary key attributes of the other (transitive dependencies).

Example:

Table following students eligible 2NF,but does not meet 3NF

Because there are non-primary key attribute (such as : City and Provincial), which has a dependence on non-primary key attributes of the other (KodePos): (City,KodePos Province)
So that the table should be decomposition :
Student (NIM, NamaMhs, Road, KodePos)
KodePos (KodePos, Province, City)

7. Boyce-Codd Normal Form (BNCF)

Boyce-Codd Normal Form constraint has a stronger form of the Normal third.To be BNCF, relations must be in the form of Normal first and forced each of the attributes depends on the function in the super key attributes.
In the example below there is a relationship seminar, is the Primary Key NPM + Seminar.

Students may take one or two seminars. Each seminar requires 2 each of the
students and led by one of the 2 seminar. Each leader can only take one
seminar course. NPM in this example and show a Seminar Pembimbing.

Relations Seminar is a form of Third Normal, but not BCNF Seminar Code
because the function depends on the Pembimbing, if any Pembimbing can only
teach a seminar. Seminar depend on one key attribute is not as super by BCNF.
So Seminar relations must be parsed into two namely:

8.Normal form of the fourth and fifth

Relations in the fourth normal form (NF 4) if the relation in BCNF and dependency not contain many values. To remove the dependency of many values from a relation, we divide the relationship into two new relations. Each relation contains two attributes that have a lot of relationship value.
Relations in fifth normal form (5NF) deal with the property called the join without any loss of information (loss less join). Fifth normal form (also called the 5 NF PJNF (projection join normal form). The cases are very rare and appear difficult to detect in practice

REFERENCE :
ER Ngurah Agus Sanjaya. Slide Part 6 - NORMALIZATION.

Databases and ER-Diagram

2009-04-19T05:29:00.000-07:00

Databases and ER- Diagram

1. Databases definition
•A set of data stored in the magnetic disk, optical disk or other secondary storage
•Collection of integrated data-related data of an enterprise (company, government or private)
Company data: manufacturing production planning, actual production data, data ordering materials, etc.
Hospital: patient data, doctor, nurse, etc.

2. Database Management System
•Collection / database combined with software applications that are based database
•Application programs are used to access and maintain databases
•The main purpose DBMS is to provide an environment that is efficient and easy to use, withdrawal and storage of data and information

3. Bit, Byte, and Field
•bit is the smallest pieces of data that contains the value 0 or 1
•Byte is a set of bit-bit similar
•Field is set of byte-byte similar, in the database used the term attribute

4. Attribute or field
•It is the nature or characteristics of an entity that provides provide detail on these entities
•A relationship can also have attributes
•Example :
Mahasiswa : Nim, Name, address

5. Attribute types
•Single vs Multivalue
Single can be filled only at most one value
Multivalue can be filled with more than one value with the same type of
•Atomic vs composition
Atomic can not be divided into the smaller attributes
Composition is a smaller combination of several attributes
•Derived Attribute
Attribute value can be derived from the value of other attributes,
example: age is the attributes resulting from the date of birth
•Null Value Attribute
Attributes that have no value to a record
•Mandatory Value Attribute
Attributes must have values

6. Record / tuple
•It is a line of data in a relationship
•Consists of the set of attributes where the attribute is to inform each other entity / relationship fully

7. Entities / File
•File is a collection of similar records and has the same elements, the same attributes but different data value.
•File type
In processing applications, files can categorize as following:
1.Master File
2.Transaction File
3.File Report
4.File History
5.File Protection
6.Job File

8. Domain
Domain is the set of values that are allowed to reside in one or more attributes. Each attribute in a database relational is defined as a domain

9. Element data key
Key elements of record which is used to find these records at the time of access, or can also be used to identify each entity / record / line

10. Species of Key
•Super key is one or more attributes of a table that can be used to identify entity / record of the table are unique (not all attributes can be super key)
•Candidate Key is a super key with minimal attributes. Candidate must not contain a key attribute of the table so that the other candidate key is certain super key but not necessarily vice versa.
•Primary key :
One of the key attributes of the candidate can be selected / specified a primary key with the three following criteria:
1. Key is more natural to use as reference
2. Key is more simple
3. Key is guaranteed its uniqueness
•Alternate Key is an attribute of the candidate key is not selected to be primary key.
•Foreign Key is any attribute that point to the primary key in another table. Foreign key will be going on a relationship that has cardinalities one to many or many to many. Foreign key is always usually put on the table that point to many.
•External Key is a lexical attribute (or set of lexical attributes) that values are always identifying an object instance.

11. ERD (Entity Relationship Databases)
•ERD is a model of a network that uses word order is stored in the abstract system.
•Differences between the DFD and ERD :
DFD is a model of network functions that will be implemented by the system,while ERD is a model that emphasizes the network data on the structure and relationship data

12. ERD Elements
•Entity
In the ER Diagram Entity is described with the form of a rectangle. Entity is something that exists in the real system and the abstract, where the data stored or where there are data.
•Relationship
ER diagram on the relationship can be described with a lozenge. Relationship is a natural relationship that occurs between entities. In general,the name given to the verb base making it easier to do the reading its relation.
•Relationship Degree
Relationship Degree is the number of entities participating in a relationship. Degree which is often used in the ERD.
•Attribute
Attribute is the nature or characteristics of each entity and relationship
•Cardinalities
tuple indicates the maximum number that can be related with entities on the other entity

13. Degree of relationship
•Unary Relationship
Model is the relationship between the entities originating from the same entity set
•Binary Relationship
Binary Relationship model is a relationship between 2 entities.
•Ternary Relationship
Ternary Relationship is a relationship between the instances of 3 types of entities are unilateral.

14. Cardinalities
There are 3 cardinalities relations, such as :
•One to one : Level one to one relationship with the one stated in the entity's first event, only had one relationship with one incident in which the two entities and vice versa
•One to many or many to one: Level one to many relationship is the same as the one to many depending on the direction from which the relationship seen. For an incident on the first entity can have any relationship with many incident on the second entity, if the one incident in which two entities can only have one relation with incident on the first entity.
•Many to many: if any incident occurs in many entity that have relationships with other entities in the incident.
•Cardinalities example :

15. ER-Diagram Notation
Symbolic notation in the ER diagram are:
1.Rectangle represent the collective entity
2.Circle represent the attributes
3.The square part is the collective relationships
4.Line as the set of relationships between the entity and the collective entity with its attribute community.

REFERENCE:
ER Ngurah Agus Sanjaya. Slide Part 5 - DATABASE DAN ER-DIAGRAM.

Chapter 4 , Data Flow Diagram

2009-04-05T03:49:00.000-07:00

CHAPTER 4

DATA FLOW DIAGRAM

1. Definition

Describes the distribution of the modules in the system to a smaller modules
Easier for users with less understandingto understand the field of computer systems that will be don

2.Context Diagram

Consist of a process and describe the scope of system
Is the highest level of the DFD that describes the entire system to the input of the system and output
System is limited by Boundary (depicted by broken lines)

3.Zero Diagram

Describes the process of the DFD
Providing views on the overall system in which, showing the main function or process that is, the flow of data and entity external
It is possible at this level of data storage
To process that does not analyzed again on the next level then added to the symbol '*' or 'P' at the end of the process
Balance of input and output (balancing) between 0 to diagram context diagram should be maintained

4.Detail Diagram

Is a digram that decipher what is the process in the diagram zero level or above
Numbering level in the DFD :

In one level there should be more than 7 units and the maximum of 9, when more should be done in the decomposition

5.Process Specifications

Each process in the DFD must have a spesification process
At the top level method is used to describe the process that can use a sentence with descriptive
In more detail level, namely on the bottom (functional primitive) requires specification of more structured
Specification process will be the guideline for the programmer to make this program (coding)
Method used in the specification process : the process of disintegration in the form of a story, decision table, decision tree

6.External Unity

Something that is outside the system, but it provides data in the system or to provide data from the system
Symbolized with the notation
External entity not part of the system including
Naming :
The name of the form of noun
Terminal may not have the same name except the same object

7.Data Flow

Is the place to flow information
Depicted with the straight line that connects the components of the system
Data flow direction is indicated with arrows and lines that gives the name on the flow of data that flows
Flow data flows between processes, data storage and data flow indicates that the foem of data input for the system

Guidelines of the name :

Name of the flow of data that consist of some words associated with the flow lines connected
No flow data for the same and the name should reflected its content
The flow of data that consist of several elements can be expressed with the group element
Avoid using the word 'data' and 'information' to give a name to the flow of data wherever possible the complete flow of data is written

Other provisions :

Name of the flow of data into a process may not be the same as the name of the data flow out of the process
Data flow into or out of data storage does not need to be given a name if :

The flow of data simple and easy to understand

Describes the data flow of all data items

There can be no flow of data from the terminal to the data storage, or vice versa because the terminal is not the part of the system, the relationship with the terminal data storage must be through a process

8.Process

The process is what have done by the system
The process can process data flows or data entry into the flow of output data
Transform the process of working one or more of the input data into one or more of the output data in accordance with the desired spesifications
Each process has one or more inputs and procedure one or more output
The process also often called buble

Guidelines of the process :

Name of the process consists of a verb and noun, which reflects the function of the process
Do not use the process as part of the name of a bubble
May not have some process that has the same name
The process should be given a number. Order number wherever possible to follow the flow of the process or sequence, but the sequence number does not mean that the absolute is a process in chronological order

9.Data Storage

Data storage is a storage place for data that exists in the system
Symbolized with a pair of parallel lines or two lines with one side open side
The process can retrieve data from or provide data to the database

Guidelines of the name :

The name should reflect the data storage
When his name more than one word must be marked with the number

10.DFD Symbol

11.Data Dictionary

Work to help the system to interpret the application in detail and osganize all elements of the data used in the system precisely so that the system analyst and have a basic understanding of the sane input, output, storage and process
In analysis, the data dictionary is used as a means of communication between the systems analyst with the user
At the system design, data dictionary is used to designe input, reports and databaeses
Flow data on the global DAD, further details can be seen in the data dictionary

Load the data dictionary as follows :

Name of data flow : must note that readers who need further explanation about a flow of data can find it easily
Alias : alias or other name of the data can be written on it
Forms of data : use to segment the data dictionary to use when designing the system
Flow data : indicates from which data flows and where the data will flow
Description : to give an explanation of the meaning of the data flow

12.Balancing in DFD

The flow of data into and out of a process must be the same as the flow of data into and out of the details of the process on the level or levels below
Name of the data flow into and out of the process must match the name of the flow of data into and out of the details of the process
Number and the name of an entity outside the process must be equal to the number of names and entities outside of the details of the process

The issues that must be considered in the DFD which have more than one level :

There must be a balance between input and output of one level and next level
Balance between level 0 and level 1 at the input or output of stream data to or from the terminal on level 0, while the balance between level 1 and level 2 is seen on the input or output of stream data to or from the process concerned
Name of the flow of data, data storage and terminals at each level must be the same if the same object

13.Restriction in DFD

Flow data may not come from outside the entity directly to other outside entities without going through a process
Flow data may not come from the savings directly to the data to outside entities without going through a process
Flow data may not be saved the data directly from the savings and other data going through a process

REFERENCE :

Hartono,Jogiyanto.2005.Analisis dan Desain Sistem Informasi : PEndekatan Terstruktur , Teori dan Praktik Aplikasi Bisnis, Yogyakarta : Andi.

CHAPTER 3, BEGINNING OBSERVATION AND ANALYSIS NEEDED

2009-03-28T23:48:00.000-07:00

CHAPTER 3

BEGINNING OBSERVATION AND ANALYSIS NEEDED

Investigation System Concept

There are differences between the purpose of the system and actual system conditions
Reports detection problem is unreal

Problem in Investigation System

· Overdo purpose

· Lack of resources and / or attitude

· The Measurement system is less accurate

· Purpose of the System that is far behind

· The differences between temporary system and idel system

Ø Problem solving:

1. Definition system that is running the investigation in detail

2. Get an ideal system consensus

3. Developed several alternative

4. Selecting the best alternative

Ø Destination investigation indicates the problem that is actually happening

Ø Constraints System In Investigation

Conduct investigations in several problems that often appear are:

1. Time

2. Cost

3. Science

4. Politics

5. Intervention

Recommendations

Results of the investigation are a recommendation that includes among others the following:

· Can’t found problems → not to take any action

· Problems that small→ perform system maintenance

· Improving the ability or the skills

· Considering modifications to the total system

· Put the problem into the development system plan that’s need to do immediately

Investigation tactics

Why we need tactics?

o Find all issues

o Knowing the causes of the emergence of problems

o Determine the appropriate solution

We need all elements of the system that can received a quote of a solution without disturbing their activities

Some of the tactics that can be do:

· Listen to opinions of the system

· Do not give the early solution

· Compare the stories of some of the system against the same case

· Note the logical inconsistency problem

Engineering Investigation

· Directly :

The questionnaire
frequently asked questions
Observations

· Indirectly :

Flow of the procedure
Reviewing documents
Sample
Tabular

Description System in this era

Enter
Exodus
File
Data elements
Transaction volume and document action
Data flow diagram

Analysis needed

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

· 4 PURPOSE THAT’S WANT to be achieved:

Explain the complete system
Information system that describes the ideal
Bringing information system to the ideal conditions at this time with attention to resource constraints
providing encouragement to the confidence in the system development

· Method
FAQ
Questioner
Observation
Procedure analysis
Observation documents

· Recourses constraints
Time
Money
Expertise
Technology
External factors

· Needs analysis document

Landing analysis: Relationships with end users, the observation process, problems in data collection
The user needs: The actual needed, 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 physic, data elements in the initial data dictionary.

Generating System Alternatives

· Tactics Options :
Selection is done before the design operational

· Designing Operational Options
Options design can be grouped into :

Input

Online Vs Off Line Data Entry
Keyed Vs Machine Readable Data Entry
Centralized Vs Decentralized Data Entry

Processing

Batch Vs Realtime record update
Sequential Vs Direct Access to records
Single Vs Multiple User update of records

Output

Traditional Vs Turn Around Documents
Structured Vs Inquiry based reports

Selecting The Proper Systems

· Compare tactics: systems based on the comparison of costs and benefits relative; there are 3 ways A system that the system is superior to the other if:

a. A cost is lower than B and both are the same benefits

b. A cost is lower than B and A give more advantage than B

c. A and B have the same but the cost advantage generated a lot more.

· Some methods Comparison System
Break Even point Analysis
Payback Period
Discounted payback period

· Internal Rate of Return :

Hardware

Software

People

Suppliers

Teleccommunications

Physical sites

· Cost details
Comparing the cost of information systems through the life of the system, analysts projected how the cost changes for the future and there are 3 models cost information system like Linear, and exponentially Step Function

· Cost information system can occur only once and can also occur on an ongoing basis.
Cost information system that occurs only once the cost on time and development costs that occur during the development of the system.
Cost information system that occur continuously among recurring cost and operational cost where the cost of this is the case when the operating system information every day.

Factors into information system

Qualitative factors that lead the performance information system that both of them :

Reduce errors
Reducing the time to fix errors
Reduce the response time from the workstation alternative
Accelerate the time of providing information
Improve security systems
Propagate update records on the source
Increasing user satisfaction

FACTORS INTO CORPORATE STRATEGY

Customer satisfaction
Sales increased
Consumer and vendor commitment

11. Information marketing products

Presenting learning SYSTEMMake short presentations.Reduce the detail description techniques

Presented clearly with visual aids
If using a model use a tool such as a laptop so that more informative
Emphasize the benefits of the proposed system with some alternative information that is appropriate condition experienced company

Continuing decision Or not
If the company decided to develop the information system, the department will do next, called the System Design Process. If then the System Development Life Cycle (SDLC) will be terminated. Often the problem will be found with the system and the study and top management will usually ask for the re-employment system to study. Model will describe some of the stages of the repeated and sometimes the information will make a decision before the repeat stage system of study. With the alternative, the decision to repeat a previous stage SDLC or not called Go - No-Go Decision.

REFERENCES :
Hartono, Jogiyanto.2005.Analisis dan Desain Sistem Informasi: Pendekatan Terstruktur, Teori dan Praktik Aplikasi Bisnis. Yogyakarta: Andi.

Public Observation of Development System

2009-03-07T20:53:00.000-08:00

Chapter 2

Public Observation of Development Systems

2.1. The importance of system information

System developmet can be called to build up a new system to change an old system overall or repaired system that is already there.

An old system must be repaired or replace because of some research, such as :

1. Problems that is in the old system, can be :

§ Problem in organization

a. Premediated falseness that makes unsecurited and the truth of data can not secure

b. The operation of the performance is not eficienty

c. Any mistakes unintentionally can makes the truth of the data is not secure

§ The growth of organization

According to the growth of organization, such as information needed that will be huge, volume data process to step on,

can get a new principle account

2. To get some opportunities

This opportunities can be market opportunities, increasing services for costumers and etc

3. Directives

Organization a new system can be happened because there are instructions from general manager or

external organization. For the example : government instruction

2.2. The purpose or goal of system information

The diagram of purpose system information

From the diagram above we can conclude :

Inside the old system, there are chances and instruction with those problems, the old system have to be developed into a new system.This new system also need to be developed, so it can solves the problem or fulfil the instruction.

2.3. The expectation organization after implementation information system

Performance
Information
Economy
Control
Efficiency
Services

2.4. The principle of developing information system

1. The developing of information system is for management

2. The developing of information system is the biggest capital investation

3. The developing of information system need a skillfull person

4. Performance and duties which is have to do in developing of information system process

5. The developing of information system is not in arrangement

6. Don’t be afraid to cancel the project
7.For line to developing of the system, we must have documentation

2.5. Three system life cycle model

The waterfall life cycle model

The waterfall model is a sequential development process, in which development is seen as flowing steadily downwards (like a waterfall) through the phases of Conception,Initiation, Analysis, Design (validation), Construction, Testing and maintenance. Waterfall model is the most well known software lifecycle development model. It is very simple to understand and use. Each next phase in this model must beginning only after the previous phase is over.

Waterfall software development model may be applicable to projects where:

1. Software requirements clearly defined and known

2. Software development technologies and tools is well known

3. New version of the existing software system is created

The diagram of waterfall life cycle model :

In Royce's original waterfall model, the following phases are followed in order :

Requirements specification
A Software Requirements Specification (SRS) is a complete description of the behavior of the system to be developed. It includes a set of use cases that describe all the interactions the users will have with the software. Use cases are also known as functional requirements. In addition to use cases, the SRS also contains nonfunctional (or supplementary) requirements

Design
Software design is a process of problem-solving and planning for a software solution. After the purpose and specifications of software are determined, software developers will design or employ designers to develop a plan for a solution. It includes low-level component and algorithm implementation issues as well as the architectural view.

Construction (AKA implementation or coding)
Implementation is the realization of an application, or execution of a plan, idea, model, design, specification, standard, algorithm, or policy

Testing and debugging (AKA Validation)
Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware thus making it behave as expected. Debugging tends to be harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge in another.
Installation
Installation (or setup) of a program (including drivers) is the act and the effect of putting the program in a computer system so that it can be executed.

Maintenance
Software maintenance in software engineering is the modification of a software product after delivery to correct faults, to improve performance or other attributes, or to adapt the product to a modified environment.To follow the waterfall model, one proceeds from one phase to the next in a purely sequential manner.

For example, one first completes requirements specification, which are set in stone.

When the requirements are fully completed, one proceeds to design.

The software in question is designed and a blueprint is drawn for implementers (coders) to follow — this design should be a plan for implementing the requirements given.

When the design is fully completed, an implementation of that design is made by coders.

Towards the later stages of this implementation phase, disparate software components produced are combined to introduce new functionality and remove errors.

The spiral life cycle model

The spiral model is a software development process combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts.Also known as the spiral lifecycle model, it is a systems development method (SDM) used in information technology (IT). This model of development combines the features of the prototyping model and the waterfall model. The spiral model is intended for large, expensive and complicated projects.

The diagram of spiral life cycle model

The steps in the spiral model can be generalized as follows:

1. 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.

2. A preliminary design is created for the new system.

3. 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.

4. A second prototype is evolved by a fourfold procedure:
evaluating the first prototype in terms of its strengths, weaknesses, and risks;
defining the requirements of the second prototype;

planning and designing the second prototype;

constructing and testing the second prototype.

The iterative life cycle model

Iterative and Incremental development is a cyclic software development process developed in response to the weaknesses of the waterfall model. It starts with an initial planning and ends with deployment with the cyclic interaction in between.

The iterative and incremental development is an essential part of the Rational Unified Process, the Dynamic Systems Development Method, Extreme Programming and generally the agile software development frameworks.

Iterative development is a rework scheduling strategy in which time is set aside to revise and improve parts of the system. It does not presuppose incremental development, but works very well with it.

A typical difference is that the output from an increment is not necessarily subject to further refinement, and its testing or user feedback is not used as input for revising the plans or specifications of the successive increments. On the contrary, the output from an iteration is examined for modification, and especially for revising the targets of the successive iterations

The diagram of iterative life cycle model

2.6. The approaches of developing system

1. Classical approach vs structured approach

Classical approach is the opposite from structured approach. Classical approach can be called traditional approach or conventional approach. Problems are appearedin classical approach, there are :

· Developing of software can be difficult

· The cost of support or cherishing system can be more expensive

· Possibility of mistakes can be increase

· The produce of system is insecured

· Problems in system project

Structured approach can be completed with tools and techniques which are needed in developing system, that’s way the result from system which is an developing will get the better definition structured.

1. Piecemeal approach vs system approach

Piecemeal approach is approach development system which is to sign in another way or aplication working.

System approach attention to information system as an unit of integration for aplication.

2. Bottom-up approach vs top-down approach

Bottom-up approach is starting from under level organization such as operasional level where we do some transaction.

Top-down approach is starting from upper level organization such as strategy level.

3. Total-system approach vs modular approach

Total-system approach is approach of developing system which is have to do together.

Modular approach is to spread difficult system to be a simple part, then system can be understandable.

4. Great loop approach vs evolutionary approach

Great loop approach according to change approaches that used modern technology.

Evolutionary approach is using modern technology only for something that needs the aplication at that time.

2.7. The meaning of methodology, methods, and algorithm

Methodology is methods, procedure, working concept, rules, and postulates which are used as knowledge art and another discipline.

Methods is a systematic ways for doing something.

Algorthm is an arrangement procedure to solve the problem in developing the information system.

2.8. Three classification of development methodology

1. Functional decomposition methodologies, there are :

HIPO(Hirearchy Plus Input-Process-Output), stepwise refinement (SR) or iterative stepwise refinement (ISR), information-hiding

2. Data- oriented- hiding

Is including data characteristic that will be processed, there are :

o Data flow oriented methodologies, are :

SADT,composite design,structured system analysis and design (SSAD)

o Data structure oriented methodologies is including input and output structure in the system there are :

JSD,W/O (Warnier/ Orr)

3. Prescriptive methodologies,are :

ISDOS (information System Design and Optimazation System) is a software that is developing in University of Michigan.

The function of ISDOS is optimizing process of developing information system.

ISDOS has 2 component sush as PSL and PSA.

PSL is a language to describe that system and not procedural language program.

PSA is software parcel which is something like a dictionary data and it used to check some data that will be created, save, and analization to get some good output.

PLEXSYS, the function of PLEXSYS is to do the transformation of statement multilevel high language to be executetable code.

PRIDE is a software that can be used for analysis / structured system design, data management, project management, and documentation.

SDM/70. SPECTRUM. SRES and SREM.

2.9. Tools and techniques for developing system

Tools system development that looks like grafik curve, such as :

HIPO diagram, data flow diagram, structured chart, SADT diagram, Warnier / Orr, Jakson’s diagram.

Beside that grafik curve tools which used in another methodology, there are some tolls grafik cuve that used in all methodology.

This tool can be scemed, there are :

Scheme to make image activity charting, scheme to make image layout charting, scheme to make personal relationship charting
Another prescriptive methodologhies, are : chapin’s approach, DBO,PAD,HOS,MSR,Stepwise, and PDL

2.10. The techniques that used in developing system

The techniques are : Management project techniques, fact finding techniques, cost- effectiveness analysis or cost benefit analysis

for doing meeting techniques,inpection techniques / walkthrough

2.1. The different between system anayst and programmer

System analyst is a person who does the analyzation system that identificate some problem to get some solution.

Analyst system also can be called information analyst, business analyst, system designer, system consultant, and system engineer.

Programmer is a person who write code program for aplication according to the project which made by system analyst.

Differences between system analyst and programmer can be found from duties and responsibility :

Programmer

1. Programmer responsibility confined from manufactured computer program

2. Programmer knowledge confined from computer technology, computer system, utilities

3. Programmer occupation to have the character of technic must be right to make instruction program manufactured

System Analyst

1. Responsibility system analyst is not exactly right from computer program manufactured but it is for all system

2. System analyst must be well known knowledge, not only in computer technology but also in their aplication level

3. Occupation system analyst makes some program become well known to solve some problem

2.12. The knowledge of a system analysis should be possed

1. The knowledge about computer technology and computer programmer

2. The knowledge about bisnis

3. The knowledge about kuantitatve methods

4. The knowledge to solve problems

5. The Comunication skill with members

LIBRARY

http://en.wikipedia.org/wiki/Iterative_and_incremental_development

http://en.wikipedia.org/wiki/Spiral_model

http://en.wikipedia.org/wiki/Waterfall_model

http://www.softdevteam.com/waterfall-lifecycle.asp

Hartono, Jogiyanto.2005.Analisis dan Desain Sistem Informasi: Pendekatan Terstruktur, Teori dan Praktik Aplikasi Bisnis. Yogyakarta: Andi.

Basic Concept of Information System

2009-02-20T21:42:00.000-08:00

Chapter 1
Basic Concept of Information System

1.1. System Basic Concept
There are two ways to definite system, such as :

1. According to the procedures, definition system is networking from procedures which is connected to do some activity or to solve some target gathered around.

Procedure definition ;

By Richard F. Neuschael, procedure is a clerical operation arrangements, which is involved some people in one or some departement, that is used for guarantee.
According to Jerry FitzGerald, Ardra F.FitzGerald and Warren D.Stallings, Jr., procedure is a right arrangements from instruction which is to explain about what ( what it have to do? ), who (who's doing that?), when(when will it have to do?), and how (how to do it?).

2.According to the components, definition system is a group from components that is connected each other to get some target.
This definition are not different from the real definition, but the approximation is different.

1.1.1. System Characteristic
1. Components
System consist of some component that is interaction that means work together to make amnions.

The component of the element's system has properties from system to run some function and to influence the whole system process. System has a bigger system called supra system
2. Boundary
Boundary is a area that separated between this system with another system.

Boundary showed the scope from that system.
3. Environment
Is everything outside of the system which is to define system operation.

Environment can give advantage to that system and either losses on the system.
4. Interface
Is some media that connected between one system with another system.

Output from subsystem can be input for another subsystem with this interface
5. Input
Is an energy that included in system. Input can be maintenance input and signal input.

Maintenance input is an energy that included in system there for the system can be operated with this input. Signal input is an energy that is processed to get some output.
6. Output
Is a energy that is processed and clarification to be a good output.
For the example ; Computer system, heat from computer system is some product which is not useful, but information is some product which is important.
7. Process
The system have some parts of the process that will change input to be output. The System products will process input.
8. Objective
The system must be have some goal and objective.

If system hasn't have goal or objective, therefore operation system will not be operated in other to the system is not useful.

The diagram of system characteristic :

1.1.2. System Clarification
The system can be clarificated from point of view system, such as :
1. System can be clarificated to be abstract system and physical system
Abstract system is a system about idea which is not we can see physically.
Physical system is a system which we can see physically.
2. System can be clarificated to be natural system and human made system
Natural system is a system which can happens from alamiah process, not made by human being.

Human made system is an artificial system human being which can do interaction between human and machine.
3. System can be clarificated to be deterministic system and probabilistic system
4. System can be clarificated to be closed system and open system

1.2. Information Basic Concept
Information is a data that will process to be a good thing and can make someone who get the information will understand about the information.

1.2.1. Information Cycle
A data that is processed by some model becomes information, the receiver then received that information, makes a decision and make some a move, which means makes another move will make some of the data's back. These data will be read as input, processed again by a model and so on makes some cycle. This cycle by John Burch with information cycle. This cycle is same as data processing cycle.

The diagram of Information Cycle

1.2.2. Quality of Information
According by John Burch and Gary Grudnitski, quality from some information depends on 3 things, such as :
1. Accurate
Information must be free from mistakes and not ordinary. Accurate means that information have to be clear to what does it means.
2. Timeliness
Information that come to the receiver could not be late
3. Relevant
Information has the advantage for people who using that information.

1.2.3. Value of information
Considered of two things, such as ;
Advantage and cost to get the information. Some information called to have quality if the advantage of the information more effective than the cost to get the information. Usually the cost of value of information can connected by cost effectiveness analyst and cost benefit analyst.

REFERENCE

Jogiyanto,Prof.Dr.HM,MBA,Akt.analisis dan desain.Yogyakarta.Penerbit andi : 2005