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1 Pertemuan 3 Konsep Dasar Teknologi Informasi Matakuliah: H0402/PENGELOLAAN SISTEM KOMPUTER Tahun: 2005 Versi: 1/0.

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Presentation on theme: "1 Pertemuan 3 Konsep Dasar Teknologi Informasi Matakuliah: H0402/PENGELOLAAN SISTEM KOMPUTER Tahun: 2005 Versi: 1/0."— Presentation transcript:

1 1 Pertemuan 3 Konsep Dasar Teknologi Informasi Matakuliah: H0402/PENGELOLAAN SISTEM KOMPUTER Tahun: 2005 Versi: 1/0

2 2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menyebutkan berbagai konsep dasar sistem informasi

3 3 Outline Materi Pengertian Sistem Proses Bisnis Sumber Daya Manusia Pendekatan Pembuatan Sistem Kendali Sistem Informasi

4 4 THE SYSTEMS VIEW Systems thinking is: –a discipline for seeing wholes –a framework for seeing interrelationships rather than things –an antidote to feeling of helplessness when dealing with complexity Peter Senge (1990)

5 5 System – a set of interrelated components that must work together to achieve some common purpose THE SYSTEMS VIEW What Is a System?

6 6 THE SYSTEMS VIEW All components are there … but they don’t work well together! An Example of Poor Design What Is a System?

7 7 System – a set of interrelated components that must work together to achieve some common purpose THE SYSTEMS VIEW What Is a System? Information System – the collection of IT, procedures, and people responsible for the capture, movement, management, and distribution of data and information

8 8 Seven Key System Elements THE SYSTEMS VIEW 1. 1.Boundary 2. 2.Environment 3. 3.Inputs 4. 4.Outputs 5. 5.Components 6. 6.Interfaces 7. 7.Storage General Structure of a System

9 9 System Component Examples THE SYSTEMS VIEW

10 10 Seven Key System Elements – System Boundary System boundary depends on: 1.What can be controlled 2.What scope is manageable within a given time period 3.The impact of a boundary change THE SYSTEMS VIEW

11 11 Seven Key System Elements – Component Decomposition A component of a system is also called a subsystem or module Hierarchical decomposition – the process of breaking down a system into successive levels of subsystems, each showing more detail THE SYSTEMS VIEW

12 12 Seven Key System Elements – Component Decomposition Goals of hierarchical decomposition: 1.To cope with system complexity 2.To analyze or change part of the system 3.To design and build each subsystem at different times 4.To direct the attention of a target audience 5.To allow system components to operate more independently THE SYSTEMS VIEW

13 13 Seven Key System Elements – Interfaces Functions of an interface: –Filtering –Coding/decoding –Error detection and correction –Buffer –Security –Summarizing Interface – point of contact between a system and its environment or between two subsystems THE SYSTEMS VIEW

14 14 Seven Key System Elements – Interfaces Interfaces built between two preexisting systems are called bridges THE SYSTEMS VIEW

15 15 Seven Key System Elements – Interfaces Possible objective of an interface: –System decoupling – changing two system components so that modifying one does not necessarily require modifying the other THE SYSTEMS VIEW

16 16 Sales Summary Reporting System

17 17 Sales Summary Reporting Subsystem

18 18 Organizations as Systems Fundamental Components of an Organization How does a change in one affect the others? THE SYSTEMS VIEW

19 19 Systems Analysis and Design Fundamental principles: – –Choose an appropriate scope (boundary selection) – –Logical before physical (what before how) Systems analysis and design (SA&D) – a process used in developing new information systems based on a systems approach to problem solving THE SYSTEMS VIEW

20 20 Systems Analysis and Design Recommended problem-solving steps: Problem (or system) is a set of problems that must be broken down into smaller, more manageable problems Single solution is not always obvious to all – alternatives should be generated and considered Understanding of problem changes, so reassess commitment to solution at various stages THE SYSTEMS VIEW

21 21 Business process – a set of work activities and resources BUSINESS PROCESSES

22 22 One way managers can evaluate a business process Evaluating Business Processes (Keen, 1997)

23 23 Business process reengineering (BPR) – radical business redesign initiatives that attempt to achieve dramatic improvements in business processes by questioning the assumptions, or business rules, that underlie the organization’s structures and procedures BUSINESS PROCESSES Business Process Redesign

24 24 BUSINESS PROCESSES Business Process Redesign Six principles for redesigning business processes: 1. 1.Organize business processes around outcomes, not tasks 2. 2.Assign those who use the output to perform the process 3. 3.Integrate information processing into the work that produces the information

25 25 BUSINESS PROCESSES Business Process Redesign Six principles for redesigning business processes: 4. 4.Create a virtual enterprise by treating geographically distributed resources as though they were centralized 5. 5.Link parallel activities instead of integrating their results 6. 6.Have the people who do the work make all the decisions, and let controls built into the system monitor the process

26 26 BUSINESS PROCESSES Business Process Redesign How IT Enables New Ways to Work

27 27 PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS The Information Systems Life Cycle Figure 9.8 Generic Systems Life Cycle

28 28 Definition Phase: End user and systems analysts conduct analysis of current system and business processes Analysis is: – –Process-oriented – –Data-oriented Business case generated and solution chosen PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS The Information Systems Life Cycle

29 29 PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Construction Phase: System designed, built, and tested System logically described, then physically Technology chosen Programs, inputs, and outputs designed Software programmed and tested User acceptance testing conducted The Information Systems Life Cycle

30 30 PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Implementation Phase: Business managers and IS professionals install new system Data and procedures from old system converted The Information Systems Life Cycle

31 31 System development methodology – framework consisting of guidelines, tools, and techniques for managing skills to address the business issue Consists of processes, tools, techniques for developing systems Prescribe who participates, roles, development stages and decision points, and formats for documentation PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Structured Techniques for Life Cycle Development

32 32 Structured Techniques for Life Cycle Development Structured techniques – tools to document system needs, requirements, functional features, dependencies, and design decisions Procedural-oriented – –Most common – –Include data-oriented, sequential, process-oriented activities Object-oriented – –Newer approach – –Often used for GUIs and multimedia applications PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS

33 33 Procedural-Oriented Techniques Provides a baseline for the new system Includes both logical and physical models Three-Step Modeling Approach PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS

34 34 Procedural-Oriented Techniques Critical appraisal of existing work processes to: Identify major subprocesses, entities, and interactions Separate processing from data flow Capture relationships between data elements Determine entities and processes within scope Three-Step Modeling Approach PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS

35 35 Procedural-Oriented Techniques Conducted by IS specialists Maps logical requirements to available technology Three-Step Modeling Approach PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS

36 36 Physical Model of a System BoxesMajor modules CylindersDatabases ArrowsFlow of data

37 37 Tools for the As-Is Model Must identify existing processes, external participants, other databases or applications, and inputs and outputs Tools used: – –Procedures, policies, manuals, forms, reports – –Other documentation – –Group interviews

38 38 Context diagram – positions the system as a whole with regard to other entities and activities with which it interacts Work process flow diagram – identifies the existing information sources, information sources that are updated, order in which steps occur, and some of the dependencies Tools for the As-Is Model

39 39 Context Diagram for Accounts Payable Tools for the As-Is Model

40 40 Work Process Flow Diagram for Accounts Payable

41 41 Tools for the Logical To-Be Model High-level model of a nonexistent new system Identifies processes and data Does not identify who does activity, where accomplished, or type of hardware or software Describes “what” rather than “how” Most closely associated with data flow diagrams (DFDs)

42 42 Tools for the Logical To-Be Model Top-Level DFD for Accounts Payable System

43 43 Top-Level DFD for Accounts Payable System External Entity Data Flow Processes Data Store

44 44 Tools for the Logical To-Be Model Process of creating a DFD: – –Identify entities that supply or use system information – –Distinguish processes from data they use or produce – –Explicate business rules that affect transformation of data to information – –Identify logical relationships – –Pinpoint duplicate storage and movement of data

45 45 Lower-level explosion DFD for Process 1.0

46 46 Second-Level DFD for Accounts Payable System Note process numbering scheme

47 47 More logical modeling required after DFDs Need to define system’s data elements and relationships: – –Data dictionary/directory (DD/D) used to define data elements – –Entity-relationship diagram (ERD) used to define relationships between entities Tools for the Logical To-Be Model

48 48 Data Dictionary Sample Entry

49 49 Entity-Relationship Diagram for Invoice and PO Tools for the Logical To-Be Model

50 50 Key Terms for Logical Data Modeling Relational Database Terminology

51 51 Tools for Documenting the Physical To-Be System Tools for physical design represent how: – –processes and data stores partitioned – –program control handled – –database organized Tools include: – –Program structure chart – –Database design – –System interface layouts

52 52 Program Structure Chart

53 53 Relationships for Data Elements in Accounts Payable Database Design (data relationships)

54 54 Input Form Layout for Vendor Invoice System Interface Input Layout Form

55 55 Check Register Report Layout with Sample Data Output Report Layout

56 56 Object-Oriented Techniques Object approach well suited for client/server applications, graphical interfaces, and multimedia data Primary advantage is ability to reuse objects programmed by others PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS

57 57 Object-Oriented Techniques PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS The Promise of Object-Oriented Approaches

58 58 Core Concepts PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Message Passing Object Encapsulation Inheritance Objects communicate with each other through messages that specify what should be done, not how it should be done

59 59 Unified Modeling Language (UML) For O-O Modeling PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS UML is standardization for O-O analysis and design modeling techniques and notations UML diagrams: – –Use-case diagrams – –Extended relationship use-case diagram – –Sequence diagram – –Class diagram Logical modeling begins with use-cases – diagrams and text forms

60 60 Use Case Diagram

61 61 Become Member Use Case Use Case – Text Form

62 62 INFORMATION SYSTEMS CONTROLS TO MINIMIZE BUSINESS RISKS Common system security risks: – –Human error – –Criminal acts – –Due to staffing changes and project management deficiencies – –Natural disasters Management policies Operating procedures Auditing function Types of Control Mechanisms

63 63 INFORMATION SYSTEMS CONTROLS TO MINIMIZE BUSINESS RISKS Controls built into the information system itself: – –To maintain data integrity – –Allow only authorized access – –Ensure proper system operation – –Protect against malfunctions, power outages, and disasters Types of Control Mechanisms IS Organization – –Backup power supplies – –Network access control – –Firewall protection Business Organization – –Ensure accurate data entry and handling – –Identify procedural errors

64 64 Types of Control Mechanisms Pre- and Post-Installation Controls INFORMATION SYSTEMS CONTROLS TO MINIMIZE BUSINESS RISKS

65 65 Pengertian Sistem Proses Bisnis Pendekatan Pembuatan Sistem Kendali Sistem Informasi Konsep Dasar Teknologi Informasi


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