• Journal of the HCI Society of Korea
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• v.9 no.1
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• pp.11-21
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• 2014

We present an experimental framework to analyze the physical reactions and causal factors of Visually Induced Motion Sickness (VIMS) using electroencephalography (EEG) signals and vital signs. We studied eleven subjects who are voluntarily participated in the experiments and conducted online and offline surveys. In order to simulate videos including global motions that could cause the motion sickness, we extracted global motions by optical flow estimation method from hand-held captured video recordings containing intense motions. Then, we applied the extracted global motions to our test videos with action movies and texts. Each genre of video includes three levels of different motions depending on its intensity. EEG signal and vital sign that were measured by a portable electrocorticography device and an electronic monometer in real time while the subjects watch the videos including ones with the extracted motions. We perform an analysis of the EEG signals using Distance Map(DM) calculated by correlation among each channel of brain signal. Analysis using the vital signs and the survey results is also performed to obtain relationship between the VIMS and causal factors. As a result, we clustered subjects into three groups based on the analysis of the physical reaction using the DM and the correlation between vital sign and survey results, which shows high relationships between the VIMS and the intensity of motions.

• Korean System Dynamics Review
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• v.16 no.1
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• pp.5-23
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• 2015

The purpose of this study is to analyze the land-use changes in the coastal areas using system dynamics modeling and to provide directions for effective management to maintain coastal dune areas. This research process consists of four steps: First, we built the basic model based on the causal loop diagram which was analyzed the land-use change of Sindu-ri Coastal Dune. Second, a time series land-use change map using Arc Map was established. Third, the validity of the basic model was tested. Finally, three simulations were performed for the cut over area($100,000m^2/y$, $150,000m^2/y$, $200,000m^2/y$) of windbreak for maintaining the coastal dune areas. Simulation of the basic model showed that the area of the coastal dune will be consistently decreased. Based on the simulation, if windbreak were cut down $150,000m^2/y$, windbreak area will be restored to the target area in 2019. This study has the limitation which the simulation is progressed with a limited variable: area. Therefore, the modeling of coastal dune should be reflected various variables in the further study.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.116-127
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• 2011

This study conducted landslide susceptibility analysis using logistic regression. The performance of prediction model needs to be evaluated considering two aspects such as a goodness of fit and a prediction accuracy. Thus to gain more objective prediction results in this study, the prediction performance of the applied model was evaluated considering two such evaluation aspects. The selected study area is located between Inje-eup and Buk-myeon in the middle of Kwangwon. Landslides in the study area were caused by heavy rain in 2006. Landslide causal factors were extracted from topographic map, forest map and soil map. The evaluation of prediction model was assessed based on the area under the curve of the cumulative gain chart. From the results of experiments, 87.9% in the goodness of fit and 84.8% in the cross validation were evaluated, showing good prediction accuracies and not big difference between the results of the two evaluation methods. The results can be interpreted in terms of the use of environmental factors which are highly related to landslide occurrences and the accuracy of the prediction model.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.65-70
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• 2000

We develop the database program for accident cause analysis which can help to increase domestic safety custom and prevent recurrence of gas accident and analyze accidents easily The program developed in this study consists of two parts. one part uses accident case database applied if than rule, so it finds root causes by inference of some input values. The other uses Root Cause Analysis Map which divided human errors and equipment difficulties and so we get general root cause by reply some proper questions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.249-250
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• 2014

이 논문은 현재 해양오염관리의 패러다임을 분석하고 시스템 과학화에도 불구하고 드러난 초동대응 실패, 대응체계혼선, 피해 최소화 실패 등 문제점과 이를 통한 변화의 전조와 인과관계를 동시에 고려할 수 있도록 인과지도(Causal Map)를 작성하여 변화를 분석했다. 현재 패러다임의 지배적 피드백 루프(Dominant Feedback Loop)를 파악하고 이를 통해 유출원을 신속하게 봉쇄할 수 있는 장비 개발과 더불어 피해자로만 인정하는 지역주민에 대하여 방제활동 및 전략수립을 결정하는 자원으로 전환시킬 수 있도록 프로그램 개발과 더불어 지원, 협조되는 기관의 증가에도 현장에서 신속하게 판단할 수 있는 체계로 개선되어야 한다.

• International Journal of Contents
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• v.8 no.3
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• pp.1-6
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• 2012

This study establishes a simple Causal Map in order to understand the structure of Social Network Services(SNS). From this, the paper proposes a simulation with drawing Simulation Model and it examines whether a Dunbar Number is available for the emergence of collective intelligence based on an on-line network. Through my analytical research, it turn out both Closed SNS and Open SNS have their own Dunbar Number. However, it appear that Open SNS can expand infinitely as it has a unique property namely weak tie. This implies that it is significant for a system or policy to be developed in order to overcome the problem of Dunbar Number, whereas restricting the extension of a network by considering the Dunbar Number would have a negative impact on emergence of collective intelligence.

• Korean System Dynamics Review
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• v.10 no.1
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• pp.109-129
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• 2009

This paper explores the ways by which the authority concerned with nuclear energy policy-making in Korea can strengthen its organisational sustainability from long-term perspective. In doing so, it applies the system dynamics approach to predict what would happen to the organisational sustainability of the nuclear energy authority in the future. In the process of analysis, it also draws causal loop map of components contained in the simulation model and constructs user-interface simulation model. It shows different predicted future values regarding organisational sustainability of the nuclear energy authority in Korea and puts forward some policy implications for practitioners and academics involved in nuclear energy policy.

• Korean System Dynamics Review
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• v.14 no.3
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• pp.5-23
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• 2013

This paper explores a structural mechanism underlying governmental reformulation. Studying cases of governmental reorganizations occurred during past 60 years, this paper constructs a causal map containing a principle of small government, an integrative organization of the government, and a committee organization. A positive feedback loop linking these factors produces an increase in the number of the committee organization in the government. Also, this paper points out that there might be a hidden self fullfilling prophecy that reinforces the principle of small government. Open experiment toward a big government is proposed to overcome the vicious circle of small government curse.

• Journal of Information Technology Applications and Management
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• v.24 no.4
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• pp.71-92
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• 2017

Finding a root cause is an essential step to solving a complex problem. Some previous studies have used the Delphi method for gathering opinions about root causes from geographically dispersed experts. However, we assert that complicated problems such as an industry ecosystem would make a general type of the Delphi method less practical because of too much psychological burden on study participants. In this study we present a preliminary list-based Delphi study method for identifying a root cause. This method was used to identify a root cause and draw a causal map for the information industry ecosystem problems.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.109-110
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• 2012

최근 지구온난화로 인한 환경 문제의 심각성이 증가하고 있다. 이에 전 산업 부문에서 지구온난화에 가장 큰 영향을 미치는 온실가스 배출량에 대한 규제를 강화하고 있다. 건설 산업에서도 온실가스 저감 대책으로 친환경 에너지 개발, 친환경 건축물 인증제도등 녹색기술의 활동이 활발히 진행 중에 있다. 그러나 이러한 활발한 연구와 노력에도 불구하고 건설공사의 각 단계별 과정에 따른 온실가스 배출량과의 이해관계를 파악하기에는 어려움이 있다. 따라서, 본 논문은 기존 연구문헌을 조사하여 건설공사 과정을 원자재 생산, 시공, 유지 및 관리, 해체 및 재활용의 단계로 구분하여, 건설공사의 각 단계에서 온실가스 배출량에 영향을 미치는 요인을 도출하고, 시스템 다이내믹스의 인과지도 작성을 통하여 온실가스 배출 원인을 분석하였다.