Ön tasarım aşamasında maliyet değerlendirme amaçlı bir uzman sistem

Abstract

The meaning of evaluation has been explained in different ways by researchers. The essence of evaluation is formed with the process of human's selecting one of the alternatives by the help of a physical model. There are three goals in evaluation of an artifact in architectural design. These are; to determine the best solution, to make the solution better and to examine the relations of building system variables and to use the results during the synthesis stage. In architecture, evaluation is constituted of process evaluation and artifact evaluation. Objective evaluation and subjective evaluation are the kinds of evaluation. The uses of computers at evaluation stage are especially seen by analysis programs. Computer aided evaluation requires high level design and decision knowledge. There can be a good evaluation with integrated programs. Building cost is the sum of all the expenditures formed during the whole life beginning from the preperation stages following the idea of construction till the demolition of the constructed building. The cost includes first cost and life-cycle cost. Cost planning is seperated in two parts, elementary based and comparative cost planning. While cost planning the goals are, to satisfy the user's payment, to balance between different parts of building with existing finance, to keep the total expenditure in designed limits by taking global cost estimations in the early stages of design. Some techniques are used while cost planning. These are, as construction cost estimation, unit method, area method, volume method, storey-enclosure method and methods based on functional elements and structural units. There's cost control during every stage of design process. There are computer programs having database abilities to take the data related with cost from the design and to represent them as tables during building cost evaluation process.

Construction industry has an important role in the economy of a country. As time,money and manpower savings are done in construction process,finance will be reduced. The process of construction begins from the inception between the architect and the client and finishes with construction. Architectural design has an influence in this process. For that reason the more economic is the design process the more economic is whole construction. in traditional design, design and evaluation processes are seen in a sequence. During design stage none of the evaluation criteria are considered. This causes feedbacks between evaluation and design process. This handicap of traditional design is solved in innovative design by integrated systems. The study in this thesis is to build an expert system which aims toevaluate costduring preliminary design. For that reason design and evaluation process are both considered. Cost is an important criterion that has to be considered during design stage. Especially,problems which will come out during further stages can be minimized by controlling cost during preliminary design stage. As^technological^nrovelt±es increase in CAAD and evaluation, computers have begun to be effectively used. During traditional design stage evaluation studies,such as feasibility studies,settlement planning,performance,energy and cost analysis and architectural drafting are done by computers. However, in innovative design the special vıı capacities of computers are used to help the designer to decide. CAAD causes a high level dialogue between the computer and designer. As a difference f rom the traditional designfthe amount of knovledge which designer requires is kept in databases of different types and sizes. in innovative design stage not nly the physical model but at the same time geometrical and mathematical models are abstraction forms; they supply the relation between the physical world and computer. Elements, vocabulary,relations,rules and grammer are the components of architectural language. Vocabulary includes architectural words and symbols.Relations are expressed by different types of lines,arrows, blocks and other similar elements.Rules are representations ofobtained design, experience and knowledge.In architectural design there are two rule applications,such as production rules and design rules. Grammer uses rules in order to describe how the words will come together to make a sentence.Architectural programs aim to define needs,wishes and principle of the client and compile them to a form that can be interpreted by the designer and as a criterion in design evaluation. in innovative design, artificial intelligence in a simple description, can be expressed as a group of approach that aims to make computer programs decide and be more intelligent. There are some differences between artificial intelligence and traditional computer programs. Artificial intelligence programs are used in cases when there's no algorithmic solution and when it's necessary to solve a problem. There are two types of search methods in architectural design, such as global and local search. The representation of architectural design in innovative design process is done by microcomputers.Expert system is a subset of a field called "Artificial intelligence". in a simple meaning,it can be expressed as algorithm ör computer program which produces solution in a field that reguires expertise.Expert systems manipulate knowledge but traditional programs manipulate data. Vd.ll Expert system Knowledge + Result System Generally known approach Data + Algorithm Program Expertise,symbolic reasoning, depth and individual knowledge are the conditions of expert system.The process of creating an expert system ör putting the appropriate knowledge in the knowledge base of the program is called as "knowledge engineering". Form of knowledge representations in expert systems are as follows:. Semantic nets. Frames. Predicate logic. Production systems. Decision tables The contents of expert systems are knowledge base, inference engine, knowledge acquisition modüle and explanatory interface. Though expert systems are highly developed in some technical branches, they are limited in architecture. Öne of the reasons is that; architectural representation has a graphic character.Design synthesis and design diagnosis are the stages vhich expert system are used in architecture graphical interaction is the main thing in creation of an artifact. There are three kinds of deductions in graphical interaction;they are,from graphics to semantic,from semantic to graphic and procedural and explanary knowledge. There are three types of knowledge in an expert system such as syntax knowledge which helps the object to connect with its own interest and other objects, semantic knowledge which is about the meaning of objects and. the last öne is evaluation knovledge which is required to interpret a design with precise attributes. ıx The meaning of evaluation has been explained in different ways by researchers. The essence of evaluation is formed with the process of human's selecting one of the alternatives by the help of a physical model. There are three goals in evaluation of an artifact in architectural design. These are; to determine the best solution, to make the solution better and to examine the relations of building system variables and to use the results during the synthesis stage. In architecture, evaluation is constituted of process evaluation and artifact evaluation. Objective evaluation and subjective evaluation are the kinds of evaluation. The uses of computers at evaluation stage are especially seen by analysis programs. Computer aided evaluation requires high level design and decision knowledge. There can be a good evaluation with integrated programs. Building cost is the sum of all the expenditures formed during the whole life beginning from the preperation stages following the idea of construction till the demolition of the constructed building. The cost includes first cost and life-cycle cost. Cost planning is seperated in two parts, elementary based and comparative cost planning. While cost planning the goals are, to satisfy the user's payment, to balance between different parts of building with existing finance, to keep the total expenditure in designed limits by taking global cost estimations in the early stages of design. Some techniques are used while cost planning. These are, as construction cost estimation, unit method, area method, volume method, storey-enclosure method and methods based on functional elements and structural units. There's cost control during every stage of design process. There are computer programs having database abilities to take the data related with cost from the design and to represent them as tables during building cost evaluation process. x. The goal of the expert system model with the goal of cost evaluation during preliminary design stage which has been prepared in the content of this thesis is, to help designer in preliminary design process and to inform him about some criteria he might forget. An expert system has been developed in this model. It has two components ; such as knowledge base and evaluation process. Knowledge base implies general and special knowledge. Batch file, design, estimation, evaluation and advices are the parts of expert system evaluation process. According to plan which is designed by CAD system in AutoCAD, program makes an evaluation on effectiveness of plan and cost, interactively with the user after some operations. Supporting this by the advices part, it tries to find the best solution. The user can be informed about the results and revision can be done according to his wish. In the first part where spatial effectiveness is evaluated, especially areas are compared with specific rules according to number of people and number of rooms. In cost evaluation part, the amount of cost is calculated based on functional elements, such as floor, wall, door and window. The final cost is compared with the maximum finance given in the beginning of the program and in case of the final cost's being more or less than finance, the user can go on with the program by revision parts. If the user wishes, advices are given and he can make revisions according to them. The main charasteristic of the program is that, it takes the data from a CAD application program which has a graphic character, makes calculations and evaluations by using these data. The program presents an interactive dialogue to the user so there becomes an answer to question process between the computer and the user.