Dewi'x Blog

PART VIII: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-05-03T05:27:00.000-07:00

NORMALIZATION

Given by ER diagram (under) . Your task is do normalization to ER that diagram and each its table.

ER- DIAGRAM

After understand ER -Diagram image upon, hereafter we do to process mapping and normalization of ER diagram image upon. Following is Mapping ER – diagram:

Explanation of Mapping ER diagram is:

Tabel Pegawai (Employee table) have No. PEG as primary key. and NO. BAG as foreign key. from sectioned table (tabel bagian). On table this have cardinality relationship n to 1 which is; To one instance on entity first gets to have many relationship with instance on entity secondly.
Tabel Bagian (sectioned table) have NO. BAG as primary key
Tabel Proyek (Project table) have NO. PRO as primary key. and NO. BAG as foreign key. from table part, and NO. PEG as foreign key. of employee table (tabel pegawai).
Tabel Tanggungan (Responsibility table) just memilki NO. PEG as foreign key of employee table (tabel pegawai).
Tabel Kerja (Job table) just has NO. PEG and NO. PRO as foreign key, any one of employee table (tabel pegawai) and project table (tabel proyek ).

Normalization of mapping ER diagram upon:

1NF (First Normal Form)

A table is said exist on normal form I if it don't exist on form un normalized table, where is happening multiplexing a sort field and enabling available field that null (empty).

2NF (Second Normal Form)

2NF normal form is accomplished in one table if have accomplished 1NF form, and all attribute besides primary key, as whole to have Functional Dependency on primary key. One table not accomplishes 2NF, if there is attribute which its dependency (Functional Dependency) just gets partial character only (just depend to one part of primary key.) If anything attribute that have no dependency for primary key, therefore that attribute has at move or is removed.

Transitive dependency:
NOPEG --> TGLLAH
TGLLAH --> UMUR

3NF (Third Normal Fom)

3NF normal form is accomplished if have accomplished 2NF form, and if no attribute non primary key one that have dependency to attribute non primary key one that another( transitive dependency ).

PART VII: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-04-25T08:25:00.000-07:00

NORMALIZATION

DATABASE DESIGN PROCESS (REVIEW)

Gathering user or business requirement
Developing E-R Model bases user or business requirements
Convert E-R Model goes to relationship gatherings (table)
Normalization is relationship to remove anomaly
Implementation goes to database by make table for each relationship already most normalization

DATABASE NORMALIZATION

Normalization are process of base structure forming data so a considerable part ambiguity can be removed. Normalization phase is begun of lightest phase (1NF) until tightest (5NF) Just usually comes up with level 3NF or BCNF because was enough is equal to result qualified tables goodness.

Why done by normalization?

Optimizing is table structures

Increasing speed
Removing same data inclusion
More efficient in storage media purpose
Reducing redundancy
Avoiding anomaly( insertion anomalies , deletion anomalies , anomalies update ).
Increased data integrity

One table is said well (efficient) or normal if pock 3 criterions as follows:

If there is decomposition table, therefore decomposition it shall be secured safe( Lossless Join Decomposition ). Its mean, after that table is untied / at decomposition becomes new tables, that new tables can result tables originally equally a hair breadth.
It's petted dependable functional at the moment data change (Dependency Preservation).
Don't breach Boyce Code Form Normal (BCNF).

If the third criterion (BCNF) can't be accomplished, therefore at least that table not breach the third phase Normal Form (3rd is Normal Form or 3NF).

FUNCTIONAL DEPENDENCY

Functional Dependency figuring relationship attributes in one relationship. An attribute is said functionally dependant on the other if we utilize to assess that attribute to determine the other attribute point.

Symbol that is utilized is for representing functional dependency. read functionally determines.

Notation: A --> B
A and B is attribute of one table. Matter functionally A determines B or B cling to A, if and only if available 2 data row with appreciative A same, therefore point B also same.

Notation: A -/-> B or A x -->B
Are opposite of previous notation.

Example FD (FUNCTIONAL DEPENDENCY)

Functional Dependency:

NRP --> Nama

Mata_Kuliah, NRP --> Nilai

Non Functional Dependency:

Mata_Kuliah --> NRP

NRP --> Nilai

Functional Dependency of point table

NRP -->Nama

Because for each point same NRP, therefore Name point also same

{Mata_kuliah, NRP} -->Nilai

Because attribute grade is depend to Mata_kuliah and NRP IS ala goes together. In other mean for Mata_kuliah and same NRP, therefore Point also with, since Mata_kuliah and NRP constitutes to key (get unique character).

Mata_kuliah -->NRP

NRP -->Nilai

FIRST NORMAL FORM (First is Normal Form - 1NF)

A table is said exist on normal form I if it don't exist on form un normalized table, where is happening multiplexing a sort field and enabling available field that null (empty).

Be not been allowed marks sense:

Attribute that valuably there are many ( Multi valued attribute ).
Attribute composite or combine of both.

So:

domain price attribute shall constitute atomic price
For example College Student Data as follows:

Tables above are ineligible for 1NF

Decomposition becomes:

College Student table:

hobby table:

SECOND NORMAL FORM (second is Normal Form 2NF)

Functional dependency x --> Y. is said heaving full if erases A attribute of x matter y. no longer functional dependent. Functional dependency x --> Y. is said partial if erases A attribute of x matter y. still functional dependent. Relationship scheme r deep shaped 2NF if each attribute non primary key A Î R full dependent functionally on primary key R.

Example

Don't accomplish 2NF, since {NIM, KodeMk} one that is looked on as primary key whereas:

{NIM, KodeMk} --> NamaMhs

{NIM, KodeMk} --> Alamat

{NIM, KodeMk} --> Matakuliah

{NIM, KodeMk} --> Sks

{NIM, KodeMk} --> NilaiHuruf

That table needs at decomposition becomes many table that measures up 2NF

Functional dependency as follows:

{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

THIRD NORMAL FORM (Third is Normal Form 3NF)

Example

Following college student table this measures up 2NF, but doesn't accomplish 3NF.

Because is still exist attribute non primary key (namely Kota and Provinsi) one that have dependency to attribute non primary key another one (namely KodePos) :

KodePos --> {Kota, Provinsi}

So that table needs at decomposition becomes:

College student( NIM , NamaMhs, Jalan, KodePos)

KodePos( KodePos , Provinsi, Kota)

BOYCE-COD NORMAL FORM (BNCF)

Boyce-Cod Normal Form have stronger compulsion of shaped the third Normal first. To become BNCF, relationship shall in first normal form and each attribute is forced hinges on function on super key attribute.

On example hereunder exists seminar relationship, Primary key is NPM + seminar. Student may take one or two seminar. Each seminar needs 2 counselors and each student led by one of between 2 that seminar counselor. Each counselor just may take one seminar just. on this example NPM and seminar points out a Counselor.

Seminar Relationship form is shaped the third Normal Form, but don't BCNF because seminar Code is still hinge function on Counselor, if each Counselor gets to teach just one seminar. Dependent seminar on one attribute is not super key as presupposed one by BCNF. Therefore seminar relationship shall be broken down as two which is:

FOURTH NORMAL FORM AND FIFTH NORMAL FORM

Relationship in shaped fourth normal from (4 NF) if relationship in BCNF and not meaty dependency a lot of point. To remove dependency there are many point of one relationship, we divide relationship become two new relationships. Each relationship contains two attributes that have relationship a lot of points.

Relationship in shaped fifth normal form (5NF) get business with property is join the so called without marks sense information loss (lossless join). fifth normal form (5 NF also so-called PJNF (projection join is form normal). This case very rare appearance and hard to be detected practically.

REFERENCES:

Ngurah Agus Sanjaya ER, S.KOM, M.KOM, Slide presentation : Normalization

PART VI: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-04-18T10:41:00.000-07:00

DATABASE AND ER-DIAGRAM

DEFINITION OF DATABASE
A database is a structured collection of records or data that is stored in a computer system. The structure is achieved by organizing the data according to a database model. The model in most common use today is the relational model. Other models such as the hierarchical model and the network model use a more explicit representation of relationships.

Coherent collection of mutually data get bearings of an enterprise (business, institution instance or private ).

Manufacturing business: production planning data, current production data, ordering data significant, etc.
Hospital: patient data, doctor, nurse, etc.

DATABASE MANAGEMENT SYSTEM
A DBMS is a set of software programs that controls the organization, storage, management, and retrieval of data in a database. DBMS are categorized according to their data structures or types. It is a set of prewritten programs that are used to store, update and retrieve a Database. The DBMS accepts requests for data from the application program and instructs the operating system to transfer the appropriate data. When a DBMS is used, information systems can be changed much more easily as the organization's information requirements change. New categories of data can be added to the database without disruption to the existing system.

BIT, BYTE, FIELD

A bit is a binary digit, taking a value of either 0 or 1. Binary digits are a basic unit of information storage and communication in digital computing and digital information theory.
A byte is a bulk of bit that a sort. Or a byte is an ordered collection of bits, with each bit denoting a single binary value of 1 or 0. The byte most often consists of 8 bits in modern systems.
Field is a group byte’s that a sort, in data basis utilized by attribute terminology.

ATTRIBUTE/FIELD
Constituting character or characteristic of an entity that provide detail explanations about that entity. A relationship can also have attribute.
Attribute example:

UNIVERSITY STUDENT: NIM, NAME, ADDRESS
CAR: NOMOR_PLAT, COLOR, TYPE, CC

ATTRIBUTE TYPES

Single vs multivalue

Single --> just can be filled at most one point
Multivalue --> can be filled by more than one point with same type of

Atomic vs is composition

Atomic --> indiscrete into smaller attribute
Composition --> constituting affiliate of some attribute which smaller

Derived Attribute

attribute that its point gets resultant of other attribute point, for example --> resulting age of date attribute comes into the world.

Null Value Attribute

Attribute that have no point for a record

Mandatory Value Attribute

Attribute who shall have point

RECORD/TUPLE
Constituting a data row in a relationship. Consisting of collection attribute's where that attribute interactions to inform entity / comprehensive relationships.

ENTITY/FILE
File constitutes collection from record what do a sort and to have same element, attribute is with but variably data value's.

File type
In application proceedings, file can at category as follows:

Parented file
Transactions file
Write-up file
History file
Protecting file
Job file

DOMAIN
Domain constitutes group of point that is let for lies deep one or more attribute. Each attribute in a relation data base is defined as a domain.

DATA ELEMENT KEY
key is record's element that is used to find record that on access time or can also be utilized to identify each entity / record / the line.

KEY TYPES

Super key constitutes one or more attribute of a table applicable to identify entity / record of unique ala table (are not all attribute can be super key ).

Candidate key is super keys with minimal attribute. Candidate key may not contain attribute of candidate's the other so key table definitely super key but was obviously contrariwise.

Primary keys

One of attribute from candidate keys to get is chosen / is determined as primary keys with three criterions as follows:

that key is more natural to been utilized as basis

that key is simpler

that key its uniqueness indemnity bond

Alternate keys is attribute from candidate keys that don't be chosen becomes primary key.

Foreign keys to constitute bungling attribute which point for primary to key on the other table. Foreign keys will happen at one particular relationship which have cardinality one to many (one to there are many) or many to many (there are many to a lot of). Foreign key. usually do ever be placed on table that aims to go to a lot of.

External keys to constitute a lexical attribute (or lexical gathering attribute) one that its point do ever identify one object instance.

ERD (ENTITY RELATIONSHIP DIAGRAM)
ERD is a model network which utilize wording that is kept in abstractive system. The difference among DFD and ERD.

DFD constitutes a logistic network model that will be performed by system.
ERD constitutes data network model that emphasizes on structure and relationship is data.

ERD ELEMENTS

ENTITY

On ER Entity's diagram is figured with square form long. Entity is aught something in real system and also abstract where data is kept or where exists data.

Relationship

On ER diagram relationship can be figured by one lozenges. Relationship is subjective artless one be become among entity. In a general way given by name by says basic job so making easy to do its relationship perusal.

Relationship Degree

are total entity who participated in one relationship. Degree that frequent being used on ERD

Attribute

are character or characteristic of every entity and also relationship

Cardinality

pointing out record optimum that relations can with entity on entity another one.

DEGREE RELATIONSHIP

Unary Relationship

are model relationship that happening among entity what do come from same entity set.

Binary Relationship

are model relationship that happening among 2 entity.

ternary Relationship

constituting relationship among instance of 3 entity types unilateral.

CARDINALITY
Available 3 cardinality relationships which is

One to One: Subjective zoom one to one stated with one instance on entity first, just has one relationship with one instance on entity secondly conversely.

One to Many or Many To One: Subjective zoom one to there are many is same with many to one pending of tenor which that relationship is seen. To one instance on entity first gets to have a lot of relationship with instance on entity secondly, if contrariwise one instance on entity just secondly gets to have relationship with one instance on entity is first.

Many To Many: happening if each instance on one entity has a lot of relationship with instance on another entity.

EXAMPLE OF CARDINALITY

NOTATION (DIAGRAM E R)
Symbol notation diagrammatically ER is :

Length square declare for entity gathering
Circle declares for attribute
Rhomb declares for relationship gathering
Lining as connecting as among relationship gathering with entity gathering and Entity Gathering with its attribute.

References:
http://en.wikipedia.org/wiki/Database
http://en.wikipedia.org/wiki/Database_management_system
http://en.wikipedia.org/wiki/Bit
http://en.wikipedia.org/wiki/Byte
slide presentation "Database and ER-Diagram" by Agus Sanjaya ER, S.Kom, M.Kom

PART V: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-04-04T06:48:00.000-07:00

DATA FLOW DIAGRAM (DFD)

Definition:

DFD often being utilized to figure a system has already there is or new system that will be developed logically without considering physical environment where the data flow (e.g. telephonic, letter etcetera) or physical environment where the will be save (e.g. file card, micro filhe, hard disk, tape, floppy disk, etc).

Data Flow Diagram (DFD) are constitute applicable assistive tool to figure information data flow and process of data, begun from data inclusion until results output .

DFD constitutes tool who will be utilized on systems developmental methodology which most structure (structured analysis and design).

There is even symbol Data Flow Diagrams:

External Entity
Process
Data flow
Data Storage

CONTEXT DIAGRAM

System Context Diagram are diagrams used in systems design to represent all external entities that may interact with a system. This diagram pictures the system at the center, with no details of its interior structure, surrounding by all its interacting systems, environment and activities. The objective of a system context diagram is to focus attention on external factors and events that should be considered in developing a complete set of system requirements and constraints.

System context diagram are related to Data Flow Diagram, and show the interactions between a system and other actors with which the system is designed to interface. System context diagrams can be helpful in understanding the context which the system will be part of.

Context diagrams are used early in a project to get agreement on the scope under investigation. Context diagrams are typically included in a requirements document. These diagrams must be read by all project stakeholders and thus should be written in plain language, so the stakeholders can understand items within the document.

ZERO DIAGRAM

Figuring process from DFD
Giving view thoroughly about handled system, pointing out function or aught process main, data flow and external entity
On this level is enabled marks sense data storage
To process that don't elaborated again on succeeding level therefore enhanced symbol ‘ * ’ or ‘ p ’ at the early process numbers
Balancing input and output (balancing) among diagram 0 by context diagram shall be petted

DETAIL DIAGRAM

Detail diagram that describes to process what aught diagrammatically zero or level on it
Numbering level on DFD:

In one advisable level has no is more than 7 processes and maximal 9, if more therefore has to be done by decomposition

SPECIFICATION OF PROCESS

1. Each process on DFD shall have process specification
2. On top level method that is utilized to figure process can by use of descriptive sentence

3. On more detail level which is on lowermost process (functional primitive) needing more specification most structure

4. Specification processes will be guidance divide programmer in makes program (coding)

5. Method that is utilized in specification of processes: b reakdown of process story type, decision table, decision tree

EXTERNAL ENTITY

Outer unity / system bounds( external entity / boundary), constituting unity at environment outer system can as person, organization or another system those are on environmentally extern will give input or accepts output of system. one that included outer unity amongst those:

An office, department or division in corporate but system open air, which is developed.
Person or a group person at organization but outside sys tem which being developed.
An organization or person of outside organization as e.g. subscription, provider.
Outdoor other information system, system being developed.
Original source of a transactions
Receiver a stop to a resulting reporting by system.

External entity symbol is:

Picture1. External entity notation at DFD

DATA FLOW

Symbol with the dart, where is data flow is flow between process, data trove. This data flow point out current of data who can as entry for system or result of system process and gets to get form as follows:

Form or document that utilized by firm
Resulting published reporting system
Output at computer screen
Entry for computer
Utterance communication
Letter or memo
Data that is read or is recorded at file
A noted stuffing on agenda book
Data transmission of a computer goes to other computer

Advisable data flow given by clear name and too have mean. Name of data flow is set inside and above its arrow line.

Picture2. Data flow that is flow from customer external entity go to process of customer order is by the name of customer order.

Inside draw data flow at DFD needs to be noticed many concepts that needs. This following is concept of data flow that needs to be noticed.

1. Concept packet of data, if two or more data are adrift from sources is same to the point same therefore have been looked on data flow one and only.

Example of Data flow which is false:

Example of Data Flow which is true:

If two data this will be handled by two disparate process, mean have a purpose that different, although its source of equal, therefore in draw as following been:

2. Diverging data flow, there is diverging data flow points out a number c.c. of data flow is same of same source to the point that different.

3. Converging data flow, data flow that converging points out many data flow that variably of source that variably jointly making for to the point same.

4. Source and to the effect concept data flow, All flow shall be resulted of is data process or making towards process (can one of or the two, which is process makes towards is not process or come from is not process to make towards process or comes from process and making towards process). This is important concept because flow is either one result's data process or will be utilized to do a process.

PROCESS

Process is activity or job that did by person, machine or computer of result a data flow that turns in at to process to been resulted data flow that will come out from process. Process function to transform one or many entry data become one or many output data correspond to desirable specification each process has one or many entries and resulting one or many outputs. Frequent process may be called by bubble

To physical data flow diagram (PDFD), process can be done by person, machine, or computer, meanwhile for logical flow's data diagram (LDFD), a process just point out process from computer. Process can be pointed out by symbol circle or with symbol length foursquare straightening with its dull angle.

Picture3. Process notation in DFD

Name application guidance processes:

Name processes consisting of job and noun word that reflection that process function
Never use word " processes "as part of name a bubble
There are no several processes that have a same name
Process shall numbered. Numbering of order possibility follow the flow or process of orders, however numbering order means not absolutely as process of order chronology.

DATA STORAGE

Data trove constitute trove of data who can as follows:

A file or database at computer system
An archives or manual note
A data place box at someone table
A manual referenced table
An agenda or book

Data trove at DFD that in symbol can with a couple lining horizontal parallel that enclosed at one of its tip.

Picture4. Data Storage Symbol at DFD

1. A few things that needs to be noticed deep data trove depiction (source's data) : Just process just that in reference to data source, since one utilizes or revamp data at data source is a process.

2. Data flow that make towards data source of a process points out to process update to saved data at data source. Update can as added as or stored record or new document, deletion or takes document, and expurgation process.

3. Indigenous data flow of data source goes to a process point out that that process utilize data that is at data source.

4. To a process that does the two, which is utilizes and data source update can be chosen by use of one lining with dart two a purpose or utilizing two dart linings.

DFD SYMBOLS

DATA DICTIONARY

Data dictionary is a register organized element data with constant definition and according to system, so user and system analyst have same savvy about input, output, and data storage component. This data dictionary really to help the system analyst in define data that is flow in system, so definition is that data get compactly been done and most structure. Formation data dictionary is performed in analysis stage and design of a system.

On analysis stage, data dictionary constitute communication device among user and system analyst about data which is flow in system, which is about in going data to system and about information which needed by user. In the meantime, on lexical system scheme stage data is utilized to design input, reporting and database.

Formation data dictionary is gone upon path up data that exists on DFD. Groove data on DFD this gets global character, in mean just showing name grooves its data without showing structure of that data path. To showing structure of ala data path most inch therefore at forms data dictionary that is gone upon on data path in DFD.

Data dictionary load things as follows:

Data flow name: shall on record that reader that require more explanation about a data flow can look for it squashy
Alias: alias or other name of data gets to be written if available
Data form: utilized to agglomerate data dictionary into its purpose one time of system scheme
Data flow: showing of which data is flow and where data goes
Explanation: giving explanation about meaning of data flow

BALANCING IN DFD

Data flow that turns in at and go out of one process have to equal data flow that turns in at and go out of details of process on level / level under it

Data streaming name which turn in at and go out of one process have with by the name of data flow that turns in at and go out of details of that process
Total and external entity of a process has to equal total and external entity of details of that process
Things who shall be noticed on DFD who has more than one level:

Shall available input balance and output among one level and next level
Balance among level 0 and level 1 is seen on input / output of data flow goes to or of terminal on level 0, meanwhile balance among level 1 and level 2 are seen on input / output of data flow goes to / of process that pertinent
Data streaming name, storage data and terminal on every level shall same if its object same

PROHIBITION IN DFD

1. Data flow may not from external entity directing to external entity another without via a process

2. Data flow may not of direct data storage make towards external entity without via a process

3. Data flow may not of direct data storage wend another data trove without via a process

4. Data flow of one process directing to wend another process without via an advisable data storage / one can maybe be avoided

References:

ER Ngurah Agus Sanjaya, S.KOM, M.KOM. Slide Part 4 - DATA FLOW DIAGRAM.

HM, Jogiyanto. 2005. Analisis & Desain Sistem Informasi. Yogyakarta: ANDI.

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

http://id.wikipedia.org/wiki/Data_flow_diagram

http://mugianet.com/attachments/012_Data%20Flow%20Diagram.pdf

PART IV: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-03-28T10:10:00.000-07:00

INITIAL INVESTIGATION AND ANALYSIS REQUIREMENT

INVESTIGATION SYSTEM CONCEPTS

Problem is difference distinctive (gap) among system aim and condition of system which actually, with other savvy why system fails to reaching to the effect system already being determined previous.

To know things any kind has already caused system failing, so an analyst advisable to do investigation earlier before do action to fix system. With investigation, an analyst will more understand problem and its system path more visceral, even in detect problem was known about problem its but still figure its outline.

There are many reporting in detects problem maybe don't quite a real or indissoluble. That thing maybe because of:

To the effect that over ideal so difficult or maybe won't be reached.

• System can't be developed since resource lack, attitude or both

• Inaccurate system measurement.

• statement of goals is dated

• The difference among idle system and temporary system

- Problem solving

• System condition formulation that walking through activity investigation in detail

• Getting ideal system consensus.

• Develop severally alternative to reduce the difference (gap) among ideal system with system that be walks.

• Choosing the best one alternative

To the effect of investigation that is subject to be strengthens or points out problem that actually happens over and above as trick an analyst for understands its system exhaustively.

CONSTRAINT IN INVESTIGATION SYSTEM

In do investigation some constraint which often emerges is:

• Time
 Analyst time comes up short resource, so just does play favorites investigation activity. Usually time is engaged cost problem be needed.

• Cost
 Cost oftentimes that is issued is engaged the duration time for activity to investigation, so management will give cost limitation.

• Knowledge
 Manager is information system tends to enjoin junior analyst that haven't had technical or science membership that adequately, so will impacted on investigation result that visceral subtracted ,ripe or complete.

• Politics
 Management or particular parties may broadcast issue that its aim to constrain investigation activity.

    • Interference

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 needs tactics?

• Find all problem

• Knowing its appearance cause problem

• Determining solution in point

Done so all system element can accept solution offer without trouble their activity

Severally tactics which can be done:

• Listening system agent opinion

• Don't give startup resolving

• Comparing story some bodies system agent to same case

• Notice the logical inconsistent problem

INVESTIGATION TECHNIQUE

Investigation Technique to cover activity:

Directly, is to know face to face what which happen deep environmental user.

• Questioner

• Question-answer

• Monitoring

Indirectly, Activity who can presto do and invisibility of personal operational, so gets to know extern or something flank that disguised of user community. This activity will dominate in the early activity SDLC, hereafter internal probe to deepen.

• Procedural flow

• Studying document

• Sample

• Tabular

CURRENT SYSTEM DESCRIPTION

Determining current system performance will struck a snag if firm have no one performance measurement default system. Too bad, tending firm doesn't update to document walking system. Hence, analyst fix document up to problem investigation system. Current system description covers explanation:

• inputs

• outputs

• files

• data elements

• transaction volume and action document

• data flow diagrams

ANALYSIS REQUIREMENT

Intensive interaction phase among analyst system with end user where development systems team point out its membership to get comment and user trust so gets good participation.

4 goal that want to be reached :

• Wording comprehensive system

• Figuring ideal information system

• Taking in ideal information system to condition of currently by notices resource constraint

•  Giving push to wearing confidence into development system

Method

• Question-answer

• Questioner

• Observation

• analysis procedure

• Document monitoring

Resource constraint

• Time

• Money

• Membership

• Technology

• External factor

Document is analysis the need

• Analysis direction: Relationship with end user, monitoring processes, about problem in data collecting

• Wearing requirement: Real requirement, Write-up requirement, training requirement and new system influence

• System constraint: Wording time and cost constraint, membership, technology and external factor

•  Document as instrumental as data collecting, statistical consensus, ala data flow logical and physical, early data element in lexical data.

GENERATING SYSTEMS ALTERNATIVES

How to current system condition approaching with condition of system which ideal?

• Making alternative to solve information system problem

• That best alternative is applied one expedient

Strategy Selection

• distributed versus centralized processing

• Changing information decision from centralized processing's data goes to decentralized end user responsibility center

• Integrated versus dispersed is database

• System designer shall regard data any kind ingoing in base's data and one turns in at File

• Surround Strategy of System Development

• Environmentally surrounding strategy is of important in term confiscation because information system of other firm may in contrast to corporate currently.

Tactics Selection

Done before operational scheme option

Operational scheme Selection

Scheme selection can be agglomerated into

o Input

§ Online Vs Off Line Data Entry

§ Keyed Vs Machine Readable Data Entry

§ Centralized Vs Decentralized Data Entry

o Processing

§ Batch Vs Realtime record update

§ Sequential Vs Direct Access to records

§ Single Vs Multiple User update of records

o Output

§ Traditional Vs Turn Around Documents

§ Structured Vs Inquiry based reports

SELECTING THE PROPER SYSTEM

Tactics compares: System than bases cost and gain relatively; There is 3 A's system trick is said more superior with another system if:

• A have inferior cost of B and gain both same

• A have inferior cost of B and A. result more gain A lot of B

• A and B have cost with but resulting gain A. more A lot of B.

Several Comparative Method system

• Break Even point Analyisis

• Payback Period

• Discounted PayBack period

• Internal Rate of Return

Cost Category

§ Hardware

§ Software

§ People

§ Suppliers

§ Teleccommunications

§ Physical sites

Cost Detail

Comparing system information cost via system life, projection analyst gets what change cost for the future and there is 3 information system cost models which is Linear, Exponential and Step Function.

System Information Cost can happen really just and gets too happening chronically.

Information system cost happening once just which is on-time cost and development cost what do happen while development system.
Information system cost happening continually among those is recurring cost and operational cost where this cost happens while operating information system everyday

INFORMATION SYSTEM FACTOR

Qualitative Factor That Aim Good Information System Performance among Those

Reducing fault zoom
Reducing time to fix fault
Reducing response time from workstation alternative
Hastening supplying time information
Increasing system security
Increasing record's source update active
Increasing wearing satisfaction

CORPORATE STRATEGY FACTOR

Consumer satisfaction
Sell zoom increases
Consumer commitment and vendor
Product marketing information

REPRESENTATION IS LEARNING SYSTEM

Doing presentation in few words
Reducing with technically explanation detail
Representation is ala is clear with visual's assistive tool
If utilizes model to utilize assistive tool e.g. laptop so more informative
Emphasize gain of information system proposal with severally alternative whatever available appropriate condition which experienced by company.

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.

PART III: ANALYSIS AND DESIGN OF INFORMATION SYSTEM

2009-03-07T18:12:00.000-08:00

CHAPTER 2: REVIEW GENERICALLY SYSTEM DEVELOPMENT

1. The Importance Of Developing An Information System
System development can mean to arrange a system a new one to replace old system as a whole. It’s required of development system because:
1. there is a problem,the appear a problem as:

· Error

Error in old system causes a old system can't operating according to that exepected.
· Organizationl growth
Causative organization growth has to be arranged by a new system . As requirement of information more that extensive,volume processing data is gotten worked up ,changing accounting a new principle . There is changing it, therefore causes a old system is not effective again.

2. To reach for opportunities

In a state competing market, information speed or time efficiency really determine success or not strategy and plan was arranged to reach for aught opportunities.

3. directives
Composing a new system would be done because instruction from on top of management or from outside environment.

2. The purpose or goal of developing an information system
To the effect in system development, which is:

To solve a problem
Reaching for opportunities
Instruction pock that is given

3. The organization’s expectations after implementing an information system

Performance: Performance can be measured from throughput and response time. Throughtput is foot up from work who can be done at the moment particular. Response time an average time which is delayed transactions betwixt or enhanced work by its time comment to comment that work.
Information: Increase to information quality is given
Economic: Increase to benefits or happening decreasing cost.
Efficiency: Increase for efiensi to had out. Efficiency in contrast to economic. Economic in reference to resource which is utilized, meanwhile efficiency is engaged how that resource utilized by the most dissipation minimum.
Service : Increase to service that gave by system

4. The principles of developing an information system

System for management :

After system is developed, then will utilize information of this system is management. So system has to get back up needful requirement by management.

System is big capital investment

All aught alternative shall be invested (opportunity cost that lost)

The best one investment shall well worth

This investment is new being said advantages if valuably with the meaning benefit or result turn back to be even greater from cost to get it. Cost benefit analysis or cost effectiveness analysis can be utilized to determine if that investment project valuably or not.

System requires educated person

Man constitutes successful prescriptive prime factor don't it a system, well in its development process, its implement, and also in its operation process. Therefore person that engages in development and also this system purpose has to be taught, taught here is not meaning have formal education.

Job and duty assignment step that shall be done in system development process.

Systems Development Life Cycle

Systems developmental process hasn't well organized

For example, one processing time of hardware's procurement is done, pettily processes another system development discontinued just umtuk wait for its coming hardware that needed, but gets to be done by another scheme that don't depend with hardware's existence.

Don't fear to cancel project

Decision to continue or cancel is true have to be evaluated the carefully. For the case of certain, where a project cannot help discontinued or canceled because have improper again, hence must be done emphatically.

Documentation that is made and is gathered up to process of system development can be utilized for communication material among system analyst with wearing system and gets to be utilized to push system involvement.

5. Three system development life cycle models

1. Waterfall Model

Explanation:

This waterfall's model constitute one way model that is begun from analysis's step,design, implementation, verification, and maintenance.

Analysis

Search process is the need and is focused on software. To know character of program who will be made, therefore softwares engineer shall understand about domain information of software, e.g. function which is needed, user interface, etcetera. Of 2 that activity (sought after system and software requirement) shall be documented and is pointed out to customer. Implementation / coding

Design

This process is utilized to change requirements upon becomes representasi before coding is begun. Design shall get mengimplementasikan requirement already being named on previous phase. As 2 previous activities, therefore this process shall also be documented as configuration of software.

Implementation

To get apprehended by machine, in this case is computer, therefore previous design shall be transformed its as understandable form by machine, which is into programming languages via processes coding. This phase constitute implementation of design's phase that technically its following worked by programmer.

Verification

Something that is made has experiment. Such even with software. All software functions that experiment shall, that software releases from error, and its result shall aptly correspond to requirement already be defined previous.

Maintenance

Preserve a software required, including in it is developmental, since software that is made is not all along just such a. While is carried on maybe just extant errors little that undiscovered previous, or there is feature increase that haven't available on that software. Needful development while marks sense changing of external corporate as when available operating system commutation, or another peripheral.

2. Iteratif Model

Explanation:
The difference of model waterfall is of process system development job it. If on waterfall's model happens one way, meanwhile on iteratif's model happens repetitive ala, herein available increase testing and evaluation that tests if that application still available fault or not. If system that apparently have fault therefore will do problem identification again and back to to be developed.

3. Spiral 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 usual 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. Th 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

6. Approaches of developing a system
There are some approaching to system development, which is:

Classical approach vs approach structured : So-called classical approach even with approach tradisonal or conventional approach is approach at deep system development which follow steps at cycle system lives without dibekali with tools and tech that is equal to. Meanwhile Approach most structure was proveded with by tool and needed tech deep system development, so result a stop to system which is developed will get system that most its structure is defined with every consideration and clear.

Piecemeal approach vs systems approach : Piecemeal approach is constitute system development approach that emphasizes at one particular activity or application most indeed. Mean while system approach notice information system as one terintergrasi's unity for each one activity or its application.

Bottom-up approach vs top-down approach : Approach is bottom-up ascends to be begun from organization bottom level, which is operational level where transactions is done. This approach is begun from requirement formulation to handle transactionses and on the up grade to levels on with formulate information requirement bases that transactions. Mean while approach on top down to be begun from level on organization, which is strategy planning level. This approach began by defines target and organization wisdom. Succeeding stage be been done its analysis is information the need. After information requirement is determined, therefore process is down go to transaction processing, which is determination output, input, database, operating procedures and control.

Total-system approach vs modular's approach : Total system approach constitute approach that develop concomitant system thoroughly. Mean while modular’s approach constitutes approach that tries to break down elaborate system as some part or module that modestly, so system will more perspicuous and developed

Great loop approach vs evolutionary approach : Great loop approach applies changing comprehensive concomitanting to utilize sophisticated technology. Meanwhile amends Approach apply sophisticated technology strictly for application which require even at that moment and will continually be developed for period next follow its requirement correspond to aught technology developings.

7. The meaning of methodology, method and algorithm

Methodology is unitary method which utilized by a scholarships.
Method is someway, tech that sistematik to work something.
Algorithm is Medley procedure to solve a period.

8. The three classifications of development methodology

Functional decomposition methodologies

Emphasizing system resolving becomes subsystem

Example: HIPO, Stepwise refinement (RS), iterative stepwise refinement (ISR), information hiding.

data oriented Methodologies

Emphasize on processed data characteristic.

data flow oriented's Methodologies: types appropriate modules data elements Example: SADT (Structure Analysis and Design Techniques), Composite Design, Structured Systems analysis and design(SSAD)

data structure oriented's Methodologies: input structure and output. Example: JSD (Jakson’s Systems Development), W/O (Warnier/Orr)

Prescriptive

Usually been provided by software maker factory

ISDOS (Information System Design and Optimization System)

PLEXSYS

PRIDE

SDM/70 (Systems Development Methodology/70)

SPECTRUM

SRES dan SREM

Beberapa prescriptive methodologies yang lainnya

9. Mention tools for developing a system

Systems development tools which get graph form amongst those:

HIPO is diagram

flow's data diagram

Structured chart

SADT

Warnier / Orr is diagram

Jakson ’ s diagrams

Tool that utilizes to design:

Activity charting

Systems flowchart

flowchart's program that as:

logic flowchart's program

Detail computer programs flowchart

Paperwork flowchart or form flochart

relationship flowchart's database

Process flowchart

Gantt chart

Layout charting

Personal relationship charting

Working distribution chart

Organization chart

10. Techniques used in developing a system

Project management techniques: for scheduling to project, example: CPM and pert
Fact finding techniques: to gather and determines fact. Its tech: Interview, Observation, questionnaires, sampling
analisis's tech cost / benefit: cost benefit analysis and cost effectiveness analysis
tech for going meeting

11. The differences of being a system analyst and a programmer and also mention what are the knowledge a system analyst should process.

Analysis is system and Pemrogram

System analyst: person that analyse system or studies problems and determine system user requirements to identify well-grounded resolving.

Pemrogrammer: person that write program code for a given application bases engineering that made by system analyst.

System analyst on call bridges distinctive happening science among system user and pemrogrammer

knowledge a system analyst should process

A System Analyst shall have ability and knowledge as:

Data processing tech, computer's technology and computer's mathematics.

Science about bosnis in common

Science about quantitative method

Trouble-shooting membership

Communication membership among person

membership builds relationship among person

References:

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

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

http://hansiaditya.wordpress.com/2007/09/25/waterfall-process-model/

http://elista.akprind.ac.id/upload/files/3098_MATERI_1.PDF

SYSTEM INFORMATION ANALISYS AND DESIGN

2009-02-20T21:17:00.000-08:00

BASE CONCEPT OF SYSTEM AND INFORMATION

BASE CONCEPT OF SYSTEM

There are two approaches to define the system itself.
1. Procedure Approach
The system based on Procedure’s Approach. The work’s network from procedure that be related each other to finish the target.
2. Element Approach
The system is a group of elements which have interaction to reach specific purpose. The system to reaching a goal & to reaching a target (objective).

The characteristic of system

Component

A system is consist of amount the components that be interacted, it’s mean the component are work each other to from the united.

Boundary

Boundary of system is scope area between another system and environment. supra system -> subsystem of large

Environments

Whatever beyond the boundary of system which influencing the operation of system.

Interface

The interface between one sub system with the other of subsystem.

Input of system

The energy that be entered to system. The input are maintenance input and signal input. The maintenance input is the energy that be entered in other to that system can be operated. The signal’s input is the energy that be processed to get the output.

Output of system

Output is product from processing energy and a clasification become benefit output.

Processing of system

The system is have a part process will be change input become output.

Objective of system

the system certain have goal or objective. If the system do not have a goal, therefor the operation system do not have benefit. The system have been told to succeed if have reached goal or objective.

The Classification of System
The system can be classificated from several vision, there are :

Abstract System & Physical System

Natural System & Human Made System

The determinictic System & Probabilistic System

The Closed System & Open System

BASE CONCEPT OF INFORMATION
What is that information? until very important, this mean for system?

The information is processed of data becoming more useful form which accepting this information

information of cycle:

Quality of Information

Accurate

The information free from mistakes and do not have meaning which diffraction / misleading

Timeliness

The information which coming to receiver must be timeliness.

Relevant

The information must have benefit for everyone which using the information.

Value of Information
considered of 2 (two) factor, that is:
advantage and cost to get that information. Some information called to be have quality if the advantage of information more effective than the cost to get that information.
Usually the cost of value of information can connected by cost effectiveness analyst and cost benefit analyst.