8
2.2. Tools for Analysis
2.2.1. Decision Support System
Turban 1995 stated that decision support system is an interactive, flexible and adaptable computer based information system, especially developed for supporting the
solutions of a non-structured management problem for improved decision making. A Decision Support System allows decision-makers to combine personal judgment with
computer output, in a user-machine interface, to produce meaningful information for support in a decision-making process. Such systems are capable of assisting in solution of
all problems structured, semi-structured and unstructured using all information available on request. They use quantitative models and database elements for problem solving and an
integral part of the decision-maker’s approach to problem identification and solution Simonovic, 1998.
By definition, decision-making is a process of choosing among alternative courses
of action for the purpose of achieving a goal or goals Turban 1995. Managerial decision- making is synonymous with the whole process of management: planning, directing,
controlling, and organizing which involves a series of decision-making activities. Decision Support System DSS
is an interactive, flexible and adaptable Computer-Based
Information System CBIS, specially developed for supporting the solution of a particular
management problem for improved decision-making Turban 1995. According to Sol in Terfai and Schrimpf 2004, decision support is the
development of approaches for applying information systems technology to increase the effectiveness of decision making in situations where the computer can support and enhance
9 human judgment in the performance of tasks that have elements, which cannot be specified
in advance. Actually, there are many definitions of a DSS. There is a general agreement that these systems focus on decisions and on supporting rather than replacing the users
decision-making process. There is also a general consensus in the definitions of DSS that both database and model components are usually required to fully support decisions. Many
of todays DSS focus on problem solving rather than on supporting the modeling process, but the main goal of a DSS should be to provide decision makers with tools for interactively
exploring, designing and analyzing decision situations. Users should be able to perform the following functions: they can analyze decision situations according to their personal styles
and knowledge; they can build and compare various quantitative models; they can adapt these models to changing conditions; can evaluate different aspects of their activities using
a variety of different means Terfai and Schrimpf, 2004.
Figure 4 . Conceptual model of DSS Turban, 1995
10 DSS is composed of several software components: Data Management, Model
Management, Communication Dialog Subsystem, and Knowledge Management Turban,
1995: 1
Data Management: The data management includes the database which contains relevant data for the situation and is managed by software called database management system
DBMS, where DBMS containing relevant data and computer program utilities to manage a database.
2 Model Management: A software package that includes various models: statistics,
mathematics, economics, environmental, qualitative models that provide system’s analytical capabilities. Model Management System, Modeling Language, Model
Directory, Model Execution, Integration, and Command or other quantitative models that provide the system’s analytical capabilities and an appropriate software
management 3
Dialog Management: includes user interface that enables easy, interactive and communicative interaction between users and DSS. Dialog Management is managed by
software called dialog management system DGMS.
4 Knowledge Management: a subsystem that supports logical interconnection and
integration between data and model management. This optional subsystem can support any of the other subsystem or act as an independent component.
Within the framework of management information systems Mittra in Simonovic, 1998 the DSS has four primary characteristics:
1 It helps decision-makers at the upper levels;
11 2
It is flexible and responds quickly to questions; 3
It provides “what if” scenarios; and 4
It considers the specific requirements of the decision-makers. In the period since DSS came to prominence there has been considerable growth in
the importance of geographic information systems GIS. This growth in GIS reflects the decreased cost of the required technology and the increasing availability of appropriate
spatial data. Recent improvements in mainstream computer technologies facilitate this spread of the use of spatial data. These include inexpensive gigabyte sized hard disks, large
high-resolution color monitors, graphics accelerators and CD-ROM storage. This explosion in the use of computer technology can also be seen in other areas, where a virtuous circle of
declining hardware costs leads to larger software sales and therefore reduced software costs. Little 1970 “model-based set of procedures for processing data and judgments to
assist a manager in his decision making” Assumption: that the system is computer-based and extends the user’s capabilities. Moore and Chang 1980, DSS are 1 Extendible
systems, 2 Capable of supporting ad hoc data analysis and decision modeling, 3 Oriented toward future planning, and 4 Used at irregular, unplanned intervals. Bonczek et
al. 1991, DSS is a computer-based system consisting of 1 A language system -- communication between the user and DSS components, 2 A knowledge system, and 3 A
problem-processing system - the link between the other two components. Keen 1987 said that DSS apply “to situations where a ‘final’ system can be developed only through an
adaptive process of learning and evolution”. Generally the Central Issue in DSS is support and improvement of decision-making.
12 A DSS is an interactive, flexible, and adaptable CBIS, specially developed for
supporting the solution of a non-structured management problem for improved decision making. It utilizes data, it provides easy user interface, and it allows for the decision
maker’s own insights. DSS may utilize models, is built by an interactive process frequently by end-users, supports all the phases of the decision-making, and may include a knowledge
component. Most DSS have some of the following ideal features Turban 1995: 1 Supporting
structured, semi-structured, and unstructured problems by bringing human judgment and computerized information, 2 Supporting various managerial levels, ranging from top
executive to line managers, 3 Supporting individuals as well as groups organizations, 4 Supporting interdependent andor sequential decisions, 5 Supporting all phases of decision
process: a intelligence, b design, c choice, d implementation, 6 Supporting a variety of decision making processes and styles, there is a fit between the DSS and the attributes of
the individual decision makers e.g., the vocabulary and decision style, 7 Adaptive over time and easy to use, and 8 Utilizing models and knowledge.
Characteristics and Capabilities of DSS are: 1 Provide support in semi-structured and unstructured situations, includes human judgment and computerized information 2
Support for various managerial levels, 3 Support to individuals and groups, 4 Support to interdependent andor sequential decisions, 5 Support all phases of the decision-making
process, 6 Support a variety of decision-making processes and styles, 7 Are adaptive, 8 Have user friendly interfaces, 9 Goal: improve effectiveness of decision making, 10 The
decision maker controls the decision-making process, 11 End-users can build simple systems, 12 Utilizes models for analysis, and 13 Provides access to a variety of data
13 sources, formats, and types. Decision makers can make better, more consistent decisions in
a timely manner. Several benefits of DSS can be enumerated as follows: 1 Ability to support fast
and objective solution of problems, 2 Ability to explore several alternative solutions under different strategies under different configurations, 3 New insights and learning, 4
Improved management control and performance, 5 Cost savings, 6 Reusable and replicable: DSS can be reused for solving similar problems and be replicated for many
users, and 7 Improved workgroup cooperation.
Table 1 . Supports provided by DSS Turban, 1995
DSS Support Answers to Questions:
Raw data and status access What is…?
General analysis capabilities What isWhy? …
Representation models What will be? …
Causal models forecasting, diagnosis What will be Why? … Solution suggestions, evaluation
What ifHow? … Solution selection
What is best? What is good enough? …
2.2.2 Database Model
Database is a collection of non-redundant data, which is shareable among different applications representing needs of individual or group users Laurini, 1996. The
organization of database can be described in terms of records, fields, and keys. Record is a group of related fields that stores data about a subject, called the master record or activity,
which is known as the transaction record Power, 2003. Database model is a collection of conceptual tools for describing data, data relationships, data semantics, and consistency
14 constraints. The various database models can be specified into thee groups: object-based
logical models, record-based logical models, and physical models.
2.2.3 Geographic Information System
Kategori