• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.9 no.13
• /
• pp.23-28
• /
• 1986

The qualitative aspects of decision making have been the toughest problems that could nor be easily manipulated and solved by the traditional management science techniques. The expert systems has been emerged as a powerful tool for handling such difficulties. In this article, the concept, the structure of the expert systems would be reviewed and the expert systems application to management would be discussed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.30
• /
• pp.73-79
• /
• 1994

This paper propose Adaptive Maintenance as a new type of maintenance for machine failures which are unpredictable. A purpose of adpative maintenance is to decrease inconsistency. In order to pick up some of problems the traditional maintenance policy, We discussed Time Based Maintenance(TBM) and Condition Based Maintenance(CBM) with Bath-Tub Curve. By using Machine Condition Diagnosis Technique (CDT), Monitored condition maintenance deals with the dynamic decision making for diagnosis procedures at maintenance and caution level. Adaptive Maintenance is a powerful tool for Total Production Maintenance(TPM).

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.10a
• /
• pp.3-20
• /
• 2006

The following lessons have been learned from the application of reliability methods in the practice of geotechnical engineering: 1. Establishing Goals Is Important; 2. Mitigating Consequences Can Be Effective; 3. Performance Depends on Systems; 4. Physical Factors Are Important in Statistical Models; 5. Too Much and Too Little Conservatism Are Both Problems; 6. Value of Information Depends on Decision Making; and 7. Effective Communication Is Essential. While the potential for application of reliability methods in the future is unlimited, there are major needs related to each of these lessons that will have to be addressed in order to realize this potential.

• Korean Journal of Construction Engineering and Management
• /
• v.15 no.1
• /
• pp.51-61
• /
• 2014

Preventive maintenance of buildings has increased the importance of interest in that it is able to maintain the performance building has and to prevent a problem occurred in future. For improved preventive maintenance work, it should be performed to select works order clearly and preceded the accurate measurement for the state of works order. when measuring the conditions, measurement of the state of work order considering the various criteria is more effective than to measure by only criterion. But, there are something hard to evaluate exactly between the criteria because of decision-maker's subjective judgments. To solve these problems, this research proposes decision making support model to determine preventive maintenance works order using Fuzzy-sets. By using Fuzzy-sets when measuring state of work objects, it can be reduced vagueness of judgments by decision-makers. This model can be used as a tool for objective evaluation of preventive maintenance work orders and offer the guideline to perform decision-making.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.1 s.17
• /
• pp.71-79
• /
• 2004

In the stage of feasibility study of urban rehabilitation projects, the precise forecast of physical and environmental changes has great influence on the further transaction of the projects. However, various important decision makings are made by the experience and intuition of the person-in-charge in practice without the process and method for systematic and quantitative analysis. In spite of various qualitative influent factors on the projects, the feasibility studies are made by the result of economic analysis only, which often lead the projects to the crucial deficit. The main reasons of such a mal-functional transaction are due to the absence of the reasonal procedure of feasibility study and decision making reflecting the characteristics of urban rehabilitation projects. The objective of this paper is to propose feasibility study processes and decision making methods in relation to various influent factors on urban rehabilitation projects in the initial stage. The goal and process of every analysis stage and the pertinent factors and decision makings are analyzed and proposed through the survey of current research, a case study, interview with the professionals. The processes and methods are well applied to improve current problems of feasibility study of urban rehabilitation projects. In addition, the establishment of the analysis goal at three principal stage and a series of reasonable decision makings with pertinent factors to each stage will lead the project to more successful result than ever.

• Journal of Convergence Society for SMB
• /
• v.3 no.2
• /
• pp.19-25
• /
• 2013

Decision procedure was done with the evaluation of multi-criterion analysis. Importance of each criterion was considered through heuristically method, specially it was based on the heuristic least mean square algorithm. To consider coalition evaluation, it was carried out by calculation of Shapley index and Interaction value. The model output is also analyzed with the help of those two indexes, and the procedure was also displayed with details. Finally, the differences between the model output and the desired results are evaluated thoroughly, several problems are raised at the end of the example which require for further studying.

• Structural Engineering and Mechanics
• /
• v.71 no.2
• /
• pp.139-151
• /
• 2019

In a project schedule, it is possible to reduce the time required to complete a project by allocating extra resources for critical activities. However, accelerating a project causes additional expense. This issue is addressed by finding optimal set of time-cost alternatives and is known as the time-cost trade-off problem in the literature. The aim of this study is to identify the optimal set of time-cost alternatives using a multiobjective teaching-learning-based optimization (TLBO) algorithm integrated with the non-dominated sorting concept and is applied to successfully optimize the projects ranging from a small to medium large projects. Numerical simulations indicate that the utilized model searches and identifies optimal / near optimal trade-offs between project time and cost in construction engineering and management. Therefore, it is concluded that the developed TLBO-based multiobjective approach offers satisfactorily solutions for time-cost trade-off optimization problems.

• Management Science and Financial Engineering
• /
• v.10 no.1
• /
• pp.25-41
• /
• 2004

There have been many studies to build a model that can help investors construct optimal portfolio. Most of the previous models, however, are based upon the path-breaking Markowitz model (1959) which is a quantitative model. One of the most important problems with that kind of quantitative model is that, in reality, most of the investors use not only quantitative, but also qualitative information when they select their optimal portfolio. Since collecting both types of information from the markets are time consuming and expensive, making a set of target assets smaller, without suffering heavy loss in the rate of return, would attract investors. To extract only desired assets among all available assets, we need knowledge that identifies investors' preference for the risk of the assets. This study suggests two-layer decision-making rules capable of identifying an investor's risk preference and an architecture applying them to a quantitative portfolio model based on risk and expected return. Our knowledge-based portfolio system is to build an investor's preference-oriented portfolio. The empirical tests using the data from Korean capital markets show the results that our model contributes significantly to the construction of a better portfolio in the perspective of an investor's benefit/cost ratio than that produced by the existing portfolio models.

• Industrial Engineering and Management Systems
• /
• v.12 no.4
• /
• pp.389-405
• /
• 2013

A facility layout design (FLD) problem can be generally introduced as assignment of facilities (departments) to a site such that a set of criteria are satisfied or some objectives are minimized (maximized). Hence, it can be considered as a multi-criteria problem due to the presence of qualitative criteria such as maintenance or flexibility and quantitative criteria such as the total cost of handling material. The VIKOR method was developed to solve multiple criteria decision making problems with conflicting and non-commensurable (different units) criteria, assuming that compromising is acceptable for conflict resolution, the decision maker wants a solution that is the closest to the ideal, and the alternatives are evaluated according to all established criteria. This paper proposes a hierarchical analytic hierarchy process (AHP) and VIKOR approach to solve the FLD problem. A computer-aided layout-planning tool is adopted to generate the facility layout problems, as well as their quantitative data. The qualitative performance measures are weighted by AHP. VIKOR is then used to solve the FLD problem. Finally, the proposed integrated procedure is applied to three real-time examples.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.6
• /
• pp.411-423
• /
• 2020

To remove phosphorus from the effluent of public wastewater treatment facilities, hundreds of enhanced phosphorus treatment processes have been introduced nationwide. However, these processes have a few problems including excessive maintenance cost and sludge production caused by inappropriate coagulant injection. Therefore, the optimal decision of coagulant dosage and automatic control of coagulant injection are essential. To overcome the drawbacks of conventional phosphorus removal processes, the integrated sedimentation and dissolved air flotation(SeDAF) process has been developed and a demonstration plant(capacity: 100 ㎥/d) has also been installed. In this study, various jar-tests(sedimentation and / or sedimentation·flotation) and multiple regression analyses have been performed. Particularly, we have highlighted the decision-making algorithms of optimal coagulant dosage to improve the applicability of the SeDAF process. As a result, the sedimentation jar-test could be a simple and reliable method for the decision of appropriate coagulant dosage in field condition of the SeDAF process. And, we have found that the SeDAF process can save 30 - 40% of coagulant dosage compared with conventional sedimentation processes to achieve total phosphorus (T-P) concentration below 0.2 mg/L of treated water, and it can also reduce same portion of sludge production.