• Journal of Information Technology Services
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• v.13 no.4
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• pp.109-122
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• 2014

Demand of spectrum resource is tremendously increasing recently and this trend will continues in the future due to the wide spread of IT services based on cloud computing and Internet of Things technology and as well as smart devices. Recently, spectrum sharing technology has drawn attention to the spectrum policy makers as a promising way to overcome the shortage problem of scarce spectrum resource. To succeed in commercialization of spectrum sharing technology, it is necessary to prospect the future business ecosystem of spectrum sharing and develop appropriate policies and laws at the same time along with the advance of spectrum sharing technology. The purpose of this paper is to analyze casual relationships between enablers in future business ecosystem of spectrum sharing and propose policies to vitalize spectrum sharing ecosystem based on a system dynamics causal map proposed in the previous research. With the causal map and system dynamics method, it is possible to analyze feedback loops exist in the business ecosystem of spectrum sharing and build policies which optimize positive dynamics in business ecosystem of spectrum sharing. As a result, policy leverages were found in four areas; spectrum supply, spectrum demand, spectrum quality and technology, and spectrum transaction cost. For those policy leverages, 13 policies were identified and intervention timing for each policy was discussed. Finally, the promotion policies of government and market participants to vitalize spectrum sharing ecosystem were discussed.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.239-250
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• 2003

In this research, we propose a hybrid group decision support mechanism (H-GDSM) based on Fuzzy AHP (Analytic Hierarchy Process) and FCM (Fuzzy Cognitive Map). The AHP elicits a corresponding priority vector interpreting the preferred information among the decision makers. Corresponding vector was composed of the pairwise comparison values of a set of objects. Since pairwise comparison values are the judgments obtained from an appropriate semantic scale. However, AHP couldn't represent the causal relationship among information, which were used by decision makers. In contrast to AHP, FCM could represent the causal relationship among variables or information. Therefore, FCMs were successfully developed and used in several ill-structured domains, such as strategic decision-making, policy making, and simulations. Nonetheless, many researchers used subjective and voluntary inputs to simulate the FCM. As a result of subjective inputs, it couldn't avoid the rebukes of businessman. To overcome these limitations, we incorporated the Fuzzy membership functions, AHP and FCM into a H-GDSM. In contrast to current AHP methods and FCMs, the H-GDSM method developed herein could concurrently tackle the pairwise comparison involving causal relationships under a group decision-making environment. The strengths and contributions of our mechanism were 1) handling of qualitative knowledge and causal relationships, 2) extraction of objective input value to simulate the FCM, 3) multi-phase group decision support based on H-GDSM. To validate our proposed mechanism we developed a simple prototype system to support negotiation-based decisions in electronic commerce (EC).

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.617-623
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• 2008

A fine-mapping method exploiting linkage disequilibrium was used to detect quantitative trait loci (QTL) on the X chromosome affecting milk production, body conformation and productivity traits. The pedigree comprised 22 paternal half-sib families of Black-and-White Holstein bulls in the Netherlands in a grand-daughter design for a total of 955 sons. Twenty-five microsatellite markers were genotyped to construct a linkage map on the chromosome X spanning 170 Haldane cM with an average inter-marker distance of 7.1 cM. A covariance matrix including elements about identical-by-descent probabilities between haplotypes regarding QTL allele effects was incorporated into the animal model, and a restricted maximum-likelihood method was applied for the presence of QTL using the LDVCM program. Significance thresholds were obtained by permuting haplotypes to phenotypes and by using a false discovery rate procedure. Seven QTL responsible for conformation types (teat length, rump width, rear leg set, angularity and fore udder attachment), behavior (temperament) and a mixture of production and health (durable prestation) were detected at the suggestive level. Some QTL affecting teat length, rump width, durable prestation and rear leg set had small numbers of haplotype clusters, which may indicate good classification of alleles for causal genes or markers that are tightly associated with the causal mutation. However, higher maker density is required to better refine the QTL position and to better characterize functionally distinct haplotypes which will provide information to find causal genes for the traits.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.92-96
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• 2015

Due to unique characteristics of small construction companies, safety management is comprised of complex problems (e.g., resources constraints, a lack of formalized management structures, low level of management safety commitment etc.). In order to understand causal interdependencies between safety factors at different system levels (regulation, organization, technical and individual), this paper aims to develop a system dynamics (SD) model of safety management in small construction companies. The purpose of the SD model is to better understand why small construction companies have low level of safety performance. A causal loop diagram (CLD) was developed based on literature, with an attempt to map causal relationships between variables. The CLD was then converted into stock and flow diagram for simulation. Various tests were conducted to build confidence in the model's ability to represent the reality. A number of policies were analyzed by changing the value of parameters. The value of a system dynamics approach to safety management in small construction companies is its ability to address joint effects of multiple safety risk factors on safety performance with a systems thinking perspective. By taking into account feedback loops and non-linear relationships, such a system dynamics model provides insights into the complex causes of relatively poor safety performance of small construction companies and improvement strategies.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.247-251
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• 1997

FCM(Fuzzy Cognitive Map) is a fuzzy signed directed graph for representing causal reasoning which has fuzziness between causal concepts. Authors have already proposed FCM-based fault diagnostic scheme and verified its usefulness. However, the previously proposed scheme has the problem of lower diagnostic resolution as in the case of other qualitative approaches. In order to improve the diagnostic resolution, a concept of fuzzy number is introduced into the basic FCM-based fault diagnostic algorithm. By incorporation the fuzzy number into fault FCM models, quantitative information such as the transfer gain between the state variables can be effectively utilized for better diagnostic resolution. Furthermore, an enhanced TAM(Temporal Associative Memory) recall procedure and modified and modified pattern matching scheme are also proposed.

• Journal of Science Education
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• v.32 no.1
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• pp.61-72
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• 2008

The purpose of the study is to research students' proficiency with systems-thinking approach concerning water cycles and to acquire data on Earth System-related concepts based on students' feedback. To achieve the purpose of the study, I chose 4 mid-level high school juniors living in Pohang, where the high school equalization policy has not been implemented, and the students answered a questionnaire about water cycles. Then, based on the results, I created a causal map and evaluated it using systems-thinking analysis. The results of the study are as follows: First of all, among the answers of the subjects, there were 21 concepts related to the conception of the earth system : 14 of the conceptions were linked scientifically, and 7 of the conceptions were not linked scientifically. Secondly, results of the causal map of what the subjects described showed that only two students'(A and C) feedback loops were completed, and that student C's feedback loop included unscientific reasoning. In conclusion, this study indicated that the students failed to understand the water cycle with the systems-thinking approach, or alternatively they applied low-level systems-thinking approach and had a lower understanding of it.

• Proceedings of the Korean System Dynamics Society
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• 2003.02a
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• pp.57-64
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• 2003

시스템 다이내믹스는 인과지도(Causal map)를 통한 시스템 이해를 그 출발점으로 한다. 특히 시스템 사고(systems thinking)는 저량-유량 흐름도를 통한 컴퓨터 시뮬레이션을 통하지 않고서 인과지도 분석만을 통한 시스템의 이해를 시도한다. 그러나 과연 인파지도만을 가지고 시스템을 동태적 변화를 이해/예측할 수 있는가에 관하여는 낙관적 전망과 부정적 전망이 혼재되어 있는 상황이다. 본 연구에서는 인과지도 구축을 통하여 시스템의 변화를 이해하는 데 있어서 어떠한 인지적 편향(bias)이 개입되는지를 탐색하고자 한다. 만일 심리적 편향이 존재한다면. 시스템 사고는 오류로부터 자유로울 수 없을 것이다. 본 연구에서는 이러한 오류의 존재를 탐색함으로써 시스템 사고의 제한정과 그 극복방안에 관하여 논의하고자 한다.(중략)

• Korean System Dynamics Review
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• v.15 no.4
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• pp.129-159
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• 2014

This Study discuss exploring normative-prescriptive factors after the themes on Organizational learning categorize two descriptive/explanatory-perspectives, prescriptive/normative dimension. The former would contain information processing model, theory of action, organizing in organization, while Senge's suggestion on Learning Organization may compose the latter. Each perspective is reconstructed and reinterpreted into the causal mapping relationship founded on system thinking and SD. Underlying on the former try to discovery validities of the latter. But this study only put forward the integral-dynamic model of organizational learning without empirical simulation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.283-290
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• 1993

Cognitive map is used for structuring and analyzing complex and unstructured decision environments, and it is a tool for graphically representing interrelationships among a variety of factors. It is a representation of the subjective perception of individual decision maker. Usually it is constructed by a number of experts at group level. This paper presents the technique of building an accurate cognitive map through several tests about the preliminary generated one. This paper also proposes an approach for aggregating the causal intensities of multiple experts.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.1-9
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• 2008

Fuzzy Cognitive Map, one of ways to model, describe and infer reasoning relations, is widely used in the field of reasoning knowledge engineering. Despite of the natural and easy understanding of decision and smooth explanation of relation between front and rear, reasoning relation is organized with mathematical haziness and complex algorithm and rarely has an interactive user interface. This paper suggests an interactive Fuzzy Cognitive Map(FCM) construction support system. It builds a FCM increasingly concerning multiple experts' knowledge. Futhermore, it supports user-supportive environment by dynamically displaying the structure of Fuzzy Cognitive Map which is constructed by the interaction between experts and the system.