• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.10a
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• pp.42-46
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• 1999

Knowledge management(KM) is emerging as a robust management mechanism with which an organization can remain highly intelligent and competitive in a turbulent market. Organization memory(or knowledge) is at the heart of KM success. How to create organizational memory has been debated among researchers. In literature, a wide variety of methods for creating organizational memory have been proposed only to prove that its applicability is limited to decision-making problems which require shallow or non-causal knowledge type. However, organizational memory with a sense of causal knowledge is highly required in solving complicated decision-making problems in which complex dynamics exist between various factors and influence each other with cause and effect relationship among them. In this respect, we propose a new approach to creating a causal-typed organizational memory (CATOM), which has a form of causal knowledge and is represented in a matrix form, by using an inference diagram. An algorithm for CATOM creation is suggested and applied to an illustrative example. Results show that our proposed KM approach can effectively equip an organization with semi-automated CATOM creation and inference process which is deemed useful in a highly competitive business environment.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.12
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• pp.941-950
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• 2000

OPKFDD(Ordered Pseudo-Kronecker Functional Decision Diagram)는 각 노드에서 다양한 확장방법(decomposition)을 취할 수 있는 Ordered-DD(Decision Diagram)의 한 종류로서 각 노드마다 Shannon, positive Davio, negative Davio 확장중의 하나를 사용하도록 하며 다른 종류의 DD와 비교해서 작은 수의 노드로 함수를 표현할 수 있다. 그러나 각 노드마다 각기 다른 확장 방법을 선택할 수 있는 특징 때문에 입력 노드에 대한 확장 방법과 입력 변수 순서의 결정에 의해서 OPKFDD의 크기가 좌우되며 최소의 노드 수를 갖는 OPKFDD의 구성은 매우 어려운 문제로 알려져 있다. 즉, OPKFDD에서의 입력변수와 각 노드의 확장 방법을 병행해서 최적의 해를 구하기 위해서는 η개의 입력변수에 대해서 η!.3$^2$$^n$$^{-1}$의 경우의 수를 고려해야 한다. 따라서 본 논문에서는 주어진 불리안 함수를 OPKFDD의 최적화 표현을 위해 노드 수를 기준으로 하여 입력변수 순서와 각 노드의 확장 방법을 함께 고려하는 혼용 유전자 알고리즘을 제안하며 최소의 노드 수를 갖는 OPKFDD를 생성하기 위해서 다양한 파라미터 값에 따른 실험결과를 제시한다.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.755-766
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• 2012

A Binary Decision Diagram (BDD) is a graph-based data structure that calculates an exact top event probability (TEP). It has been a very difficult task to develop an efficient BDD algorithm that can solve a large problem since its memory consumption is very high. Recently, in order to solve a large reliability problem within limited computational resources, Jung presented an efficient method to maintain a small BDD size by a BDD truncation during a BDD calculation. In this paper, it is first identified that Jung's BDD truncation algorithm can be improved for a more practical use. Then, a more efficient truncation algorithm is proposed in this paper, which can generate truncated BDD with smaller size and approximate TEP with smaller truncation error. Empirical results showed this new algorithm uses slightly less running time and slightly more storage usage than Jung's algorithm. It was also found, that designing a truncation algorithm with ideal features for every possible fault tree is very difficult, if not impossible. The so-called ideal features of this paper would be that with the decrease of truncation limits, the size of truncated BDD converges to the size of exact BDD, but should never be larger than exact BDD.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1774-1779
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• 2005

This paper propose the design method of the constructing the digital logic systems over galois fields using by the galois field decision diagram(GFDD) that is based on the graph theory. The proposed design method is as following. First of all, we discuss the mathematical properties of the galois fields and the basic properties of the graph theory. After we discuss the operational domain and the functional domain, we obtain the transformation matrixes, $\psi$GF(P)(1) and $\xi$GF(P)(1), in the case of one variable, that easily manipulate the relationship between two domains. And we extend above transformation matrixes to n-variable case, we obtain $\psi$GF(P)(1) and $\xi$GF(P)(1). We discuss the Reed-Muller expansion in order to obtain the digital switching functions of the P-valued single variable. And for the purpose of the extend above Reed-Muller expansion to more two variables, we describe the Kronecker product arithmetic operation.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2933-2940
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• 2022

Approximations such as the delete-term approximation, rare event approximation, and minimal cutset upper bound (MCUB) need to be prudently applied for the quantification of a seismic probabilistic safety assessment (PSA) model. Important characteristics of seismic PSA models indicate that preserving the success branches in a primary seismic event tree is necessary. Based on the authors' experience in modeling and quantifying plant-level seismic PSA models, the effects of applying negate-down to the success branches in primary seismic event trees on the quantification results are summarized along with the following three insights gained: (1) there are two competing effects on the MCUB-based quantification results: one tending to increase and the other tending to decrease; (2) the binary decision diagram does not always provide exact quantification results; and (3) it is identified when the exact results will be obtained, and which combination provides more conservative results compared to the others. Complicated interactions occur in Boolean variable manipulation, approximation, and the quantification of a seismic PSA model. The insights presented herein can assist PSA analysts to better understand the important theoretical principles associated with the quantification of seismic PSA models.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.134-142
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• 2002

LCC (Life-Cycle Cost) analysis is a practical method and a guideline for evalua-ting the economic performance of building service systems. By using the LCC analysis, the most cost-effective design decision can be made, which has the lowest LCC during the project study period among the various design alternatives. The present case shows an example of appro-priate use of the LCC analysis, by demonstrating the procedures of decision making among at-tarnative building HVAC systems at community center and congress hall of a local government.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.687-688
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• 2011

This paper presents a design method for combinational digital logic systems using time domain based multiplexing(TDBM) and common multi-terminal extension decision diagrams(CMTEDD). The proposed method can reduce the 1)hardware, 2)logic levels and 3)pins. In the logic system design, we use two types of decision diagrams(DDs), that is the common binary decision diagrams(CBDDs) and CMTEDDs. Also, we propose an algorithms to derive common multiple-terminal binary decision diagrams(CMTBDD) from CBDDs, and CMTEDDs from CMTBDDs. The CMTEDDs over CBDDs is more compactness in terms of number of non-terminal nodes, where the nodes for output selection variables are not included in the non-terminal nodes. In the logic design, each non-terminal nodes of an CBDDs and an CMTEDDs is realized by a multiplexer(MUX). In addition, we compare the proposed TDBM realization with the conventional one.

• Journal of Korean Society for Quality Management
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• v.42 no.2
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• pp.165-177
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• 2014

Purpose: This study analyzes the strategical priority to improve eco-labelling certification system, focused on biodegradable resin. Methods: This study will come up with measures to operate the eco-Label certification system related to biodegradable products more effectively and efficiently by discovering various problems related to the system, using causal loop diagram and AHP analysis. Results: This study shows that the government should play more important role while firms could also serve their roles in the initial and stabilizing stages of the eco-labelling certification system, in order to vitalize the eco-Label certification system more effective. Conclusion: This study addresses strategic eco-labelling policies on governmental and firm's operation and providers guidance to practitioners in addressing strategic decision relating to eco-labelling certification system.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.6
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• pp.316-321
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• 2000

In this paper, we proposed MBDD(Modified Binary Decision Diagram) as a multi-level logic synthesis method and a vertex of MBDD to NMOS transistors matching. A vertex in MBDD is matched to a set of NMOS transistors. MBDD structure can be achieved through transformation steps from BDD structure. MBDD can represent the same function with less vertices less number of NMOS transistors, consequently capacitance of the circuit can be reduced. Thus the power dissipation can be reduced. We applied MBDD to a full odder and a 4-2compressor. Comparing the 4-2compressor block with other synthesis logic, 31.2% reduction and 19.9% reduction was achieved in numbers of transistors and power dissipation respectively. In this simulation we used 0.8 ${\mu}{\textrm}{m}$ fabrication parameters.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.159-160
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• 2018

The domestic construction industry is changing its preference for demand and supply along with urbanization and economic development. Accordingly, initial risk assessments is more important than before. Currently, the research related to risk analysis except for apartment studies is insufficient. Therefore, the objective is to suggest a basic study on financial analysis model development by applying optimization method in residential officetel. To achieve the objective. first, the previous studies are investigated. Second, the causal loop diagram is structured based on the collected data. Third, the financial model is developed by using optimization method. In the future, the proposed model can be helpful whether or not conduct execution of an officetel development project to the decision makers.