• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.672-680
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• 2017

A solar photovoltaic system is composed of a module mounting structure, supporting trunk, and a control unit that supplies generated electrical power to an external power grid or a load. The efficiency of the system depends on the incident solar light, so the mounting structure is installed to face the sun. However, because the sun always moves, systems that track the sun have better efficiency than fixed systems. The structure experiences wind pressure, snow load, seismic load, and structure weight. The wind pressure has the most serious effect on the structure. The pressure was obtained using finite element method for various gaps between modules and angles between the panel and the ground. The wind pressure is lowest when the gap is zero, and it increases with the inclination angle. Based on the results, a mounting structure module was designed.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.38-39
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• 2010

수도권 대중교통 이용자는 2004년 서울시의 대중교통 체계 개편에 따라 교통 카드를 사용하여 버스와 지하철을 이용하게 되었다. 교통 카드를 사용하는 각 승객의 승차와 하차에 관한 데이터가 하나의 트랜잭션으로 구성되고, 하루 천만 건 이상의 트랜잭션들로 구성된 대용량 교통카드 트랜잭션 데이터베이스가 만들어지고 있다. 대중교통을 이용하는 승객들의 승차와 하차에 관한 여러 정보를 담고 있는 교통카드 트랜잭션 데이터베이스에서 유용한 패턴이나 정보를 탐사해내는 연구가 계속 진행되고 있다. 이런 연구 결과는 수도권 대중교통 정책을 입안하는데 중요한 기초 자료가 되고 수도권 승객들에게 대중교통을 보다 잘 이용할 수 있는 정보로 제공된다. 교통카드 이용률은 2006년 79.5%, 2007년 80.3%, 2008년 81.6%로 점차적으로 증가하고 있다. 대용량의 교통카드 트랜잭션 데이터베이스에 대한 연구를 살펴보면 하루 동안의 교통카드 트랜잭션 데이터베이스에서 순차 패턴을 탐사하는 알고리즘을 연구하였고[1], 승객들의 통행 패턴에 대한 분석연구를 확장하여 일 년에 하루씩 2004년에서 2006년까지 3일간의 교통카드 트랜잭션 데이터베이스로부터 승객 시퀀스의 평균 정류장 개수와 환승 횟수 등을 연도별로 비교하였다[2]. 수도권 지하철 시스템의 특성에 관한 연구로는 네트워크 구조 분석이 있었고[3], 승객의 기종점 통행 행렬(Origin-Destination trip matrix)에 의한 승객 흐름의 분포가 멱함수 법칙(power law)임을 보여주는 연구가 있었고[4], 지하철 교통망에서 모든 링크상의 승객들의 흐름을 찾아내는 연구가 있었다[5]. 본 논문에서는 교통카드 트랜잭션 데이터베이스에서 지하철 승객들의 통근 패턴을 탐사해내는 방법을 연구하였다. 수도권 지하철 네트워크에 대한 정보를 입력하고 하루치의 교통카드 트랜잭션 데이터베이스에 연구된 방법을 적용하여 8가지 통근 패턴들을 탐사해내고 분석하였다. 탐사된 패턴들 중에서 많은 승객들이 지지하는 출퇴근 패턴에 대해서는 시간대별로 승객수를 그래프로 보여주었다.

• Journal of Korean Library and Information Science Society
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• v.48 no.4
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• pp.181-207
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• 2017

The purpose of this paper is to provide values and effectiveness to libraries making a new social network service marketing model and strategy. According to study, when libraries entice library users with social network services, the users become loyal customers who give libraries long-term supports. For method of study, it establishes 15 hypotheses and proves those hypotheses with 157 responders. After inspecting hypotheses, 13 hypotheses are adopted and 3 hypotheses are dismissed. During the research, it is verified that usefulness perceived by library users is the most important factor of user satisfaction and continuous use intention which increased library users' intention to continue visiting the library. In addition, effectivness of marketing and cause are found in order of system quality, information quality, reliability, interactivity, subjective norms. In other words, the study found that library users found their information for using social network services and this attribute affects user satisfaction and ultimately continuous use intention in a positive way.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.235-244
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• 2000

This paper addresses a new method for constructing surface representation of 3D structures from a sequence of tomographic cross-sectional images, Firstly, we propose cell-boundary representation by transforming the cuberille space into cell space. A cell-boundary representation consists of a set of boundary cells with their 1-voxel configurations, and can compactly describe binary volumetric data. Secondly, to produce external surface from the cell-boundary representation, we define 19 modeling primitives (MP) including volumetric, planar and linear groups. Surface polygons are created from those modeling primitives using a simple table look-up operation. Comparing with previous method such as Marching Cube or PVP algorithm, our method is robust and does not make any crack in resulting surface model. Hardware implementation is expected to be easy because our algorithm is simple(scan-line), efficient and guarantees data locality in computation time.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.19-33
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• 2018

Collaborative consumption was suggested as a new paradigm of consumption and business model that focuses on sharing and using resources to reduce the risks of resource depletion and environmental impact. Individual consumers carry out a role not only as users but also as providers for collaborative consumption. In the present study, the authors investigated consumers' intention to participate in collaborative consumption both as providers and users. The effects of perceived benefit of collaborative consumption, subjective norms and ease of participation on the intention to participate in collaborative consumption were analyzed. The perceptions on benefits and subjective norms were relatively high, while the perception on ease of participation was relatively low. The effects of subjective norms and ease of participation on the intention to participate in collaborative consumption were significant. The result shows that support from one's reference group and the perception on ease of participation have significant positive effects on the intent to participate in collaborative consumption. Therefore, communication strategies for developing a positive consumer attitude and a social consensus about the necessity of collaborative consumption are needed.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.857-864
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• 2012

Reviewing the statistics of harbor shipment of hazardous and noxious substance and the past spill accidents of HNS enabled us to assess the potential risks of transportation of HNS through the major harbors in Korea. Ulsan, Yeosu, Daesan port are relatively evaluated high risk in fire, health and environment disaster. Through the analysis of domestic preparedness to HNS accidents, the supplement of expertise resource to respond the vulnerability of the explosion, the fire and the physiological hazard, is required. Based on this risk assessment and review of the advanced case of Japan in building up HNS response system, a resource model at a national level was proposed which differentiates the sea areas for the proper allocation of resources to respond effectively to HNS accidents in the future.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.457-461
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• 2010

Even though face recognition researches have been developed for a long ago, there is no practical face recognition system in real life. It is caused by several real situations where non-facial components such as glasses, scarf, and hair occlude facial components while facial images in a face database are well designed. This occlusion decreases recognition performance. Previous approaches in recent years have tried to solve non-facial components but have not resulted in enough performance. In this paper, we propose a method to handle this problem based on support vector data description, which trains the hyperball in feature space to find the minimum distance estimating the approximated face. In order to evaluate its performance and validate the effectiveness of the proposed method, we make several experiments and the results show that the proposed method has a considerable effectiveness.

• Journal of KIISE:Software and Applications
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• v.35 no.11
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• pp.681-691
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• 2008

In this paper, we have evaluated and compared each feature and feature combinations necessary for statistical Korean dialogue act classification. We have implemented a Korean dialogue act classification system by using the Support Vector Machine method. The experimental results show that the POS bigram does not work well and the morpheme-POS pair and other features can be complementary to each other. In addition, a small number of features, which are selected by a feature selection technique such as chi-square, are enough to show steady performance of dialogue act classification. We also found that the last eojeol plays an important role in classifying an entire sentence, and that Korean characteristics such as free order and frequent subject ellipsis can affect the performance of dialogue act classification.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.6
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• pp.187-194
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• 2020

This paper proposes a website fingerprinting method using ensemble learning over a Tor network that guarantees client anonymity and personal information. We construct a training problem for website fingerprinting from the traffic packets collected in the Tor network, and compare the performance of the website fingerprinting system using tree-based ensemble models. A training feature vector is prepared from the general information, burst, cell sequence length, and cell order that are extracted from the traffic sequence, and the features of each website are represented with a fixed length. For experimental evaluation, we define four learning problems (Wang14, BW, CW_T, CW_H) according to the use of website fingerprinting, and compare the performance with the support vector machine model using CUMUL feature vectors. In the experimental evaluation, the proposed statistical-based training feature representation is superior to the CUMUL feature representation except for the BW case.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.4 s.148
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• pp.512-520
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• 2006

The effects of flexibilities of supporting structures on shaft alignment are growing as ship sizes are Increasing mainly for container carrier and LNG carrier. But, most of classification societies not only do not suggest any quantitative guidelines about the flexibilities but also do not have shaft alignment design program considering the flexibility of supporting structures. A newly developed program, which is based on innovative shaft alignment technologies including nonlinear elastic multi-support bearing concept and hull deflection database approach, has S basic modules : 1)fully automated finite element generation module, 2) hull deflection database and it's mapping module on bearings, 3) squeezing and oil film pressure calculation module, 4) optimization module and 5) gap & sag calculation module. First module can generate finite element model including shafts, bearings, bearing seats, hull and engine housing without any misalignment of nodes. Hull deflection database module has built-in absolute deflection data for various ship types, sizes and loading conditions and imposes the transformed relative deflection data on shafting system. The squeezing of lining material and oil film pressures, which are relatively solved by Hertz contact theory and built-in hydrodynamic engine, can be calculated and visualized by pressure calculation module. One of the most representative capabilities is an optimization module based on both DOE and Hooke-Jeeves algorithm.