• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.4
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• pp.51-62
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• 2012

According to the Lighthill and Whitham's shock wave model, a shock wave exists even in a homogeneous speed condition. They referred this wave as unobservable- analogous to a radio wave that cannot be seen. Recent research has attempted to identify how such a counterintuitive conclusion results from the Lighthill and Whitham's shock wave model, and derive a new asymptotical shock wave model. The asymptotical model showed that the shock wave in a homogenous speed traffic stream is identical to the ambient vehicle speed. Thus, no radio wave-like shock wave exists. However, performance tests of the asymptotical model using numerical values have not yet been performed. We investigated the new asymptotical model by examining the implications of the new model, and tested it using numerical values based on a test scenario. Our investigation showed that the only difference between both models is in the third term of the equations, and that this difference has a crucial role in the model output. Incorporation of model parameter${\alpha}$ is another distinctive feature of the asymptotical model. This parameter makes the asymptotical model more flexible. In addition, due to various choices of ${\alpha}$ values, model calibration to accommodate various traffic flow situations is achievable. In Lighthill and Whitham's model, this is not possible. Our numerical test results showed that the new model yields significantly different outputs: the predicted shock wave speeds of the asymptotical model tend to lean toward the downstream direction in most cases compared to the shock wave speeds of Lighthill and Whitham's model for the same test environment. Statistical tests of significance also indicate that the outputs of the new model are significantly different than the corresponding outputs of Lighthill and Whitham's model.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.21-31
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• 2007

The intellectual property system was very important to the past industrial society. It is so important to the 21C information age. It is a leading role to developing these information society. Not only the digital content control but the technology of software source code for the intellectual property is so much mean to international competition. On occurring disputation property, we have to prove the fact, there is a problem to discriminate the original source code. In this paper, we make a study of the digital licence prototype for discriminate the original source code. Reserved words of software source code by parsing express to XML file that have hierarchical structure. Then, we can express architecture of software source code by tree structure form instead of complex source code. And we make a study of the indexing and searching to search digital license.

• Journal of KIISE:Databases
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• v.36 no.5
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• pp.366-373
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• 2009

In this paper, we propose a similarity search algorithm for image databases. One of the central problems regarding content-based image retrieval (CBIR) is the semantic gap between the low-level features computed automatically from images and the human interpretation of image content. Many search algorithms used in CBIR have used the Minkowski metric (or $L_p$-norm) to measure similarity between image pairs. However those functions cannot adequately capture the aspects of the characteristics of the human visual system as well as the nonlinear relationships in contextual information. Our new search algorithm tackles this problem by employing new similarity measures and ranking strategies that reflect the nonlinearity of human perception and contextual information. Our search algorithm yields superior experimental results on a real handwritten digit image database and demonstrates its effectiveness.

• Journal of KIISE
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• v.42 no.11
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• pp.1404-1409
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• 2015

In this paper, we present a novel approach to analyzing large-scale JavaScript applications statically by tuning the analysis scalability, possibly sacrificing soundness. For a given sound static baseline analysis of JavaScript programs, our framework allows users to define a sound approximation of selected executions that they wish to analyze, and it derives a tuned static analysis that can analyze the selected executions practically. The selected executions serve as parameters of the framework by taking a trade-off between the scalability and the soundness of the derived analyses. We formally describe our framework in the abstract interpretation setting and present two instances of the framework.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.239-251
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• 2006

Zheng's signcryption scheme is a new encryptical scheme of which can save more expense than those of the current signature encryption by using digital signature and symmetric key encryption logically. The current signcryption schemes have a problem that is to be exposed the secret key of the receiver in the case of checking repudiation of origin by the third party. To solve this problem, a solution suggested in this paper is to use multi-purpose ID-based signcryption scheme with anonymity and unlinkability. This solution is safe and more efficient than current signcryption schemes because the suggested scheme keeps the security of the random oracle model as using Weil-pairing in encryption. and follows a formal proof of semantic security of the decisional Diffie-Hellman problem.

• The Journal of Korean Association of Computer Education
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• v.3 no.1
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• pp.75-86
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• 2000

No matter how a great value the classwork through Internet may be, the value of Internet can be of negative value if teachers do not intend to make good use of it. Based on this assumption, this research is to show how to draw up a plan for utilizing a effective course of the classwork in high school through Internet, which is now being given attention to an educational environment as a innovative way supporting various educational possibilities compared with a traditional system of education. In addition, this study focuses on the investigation on the classwork through Internet by on-the-spot teachers as a part of all possible efforts for spreading the classwork with network.

• Journal of Digital Contents Society
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• v.15 no.5
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• pp.621-630
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• 2014

The purpose of this study is to extract metaphor characteristics of Social Network Service. Social Network Service is different from existing media only available in one-way communication, each individual expands opinion by sharing daily life and opinion directly and interpreting another user's post. This Study premise that the reason of converting from passive reader to active enunciator is the metaphor characteristics of Social Network Service by 'Source Domain' and 'Target Domain'. In addition, this study examines the meaning of structure user's text production and interpreting based triple mimesis of Paul Ricoeur. This study has significance as arguing with existing study on SNS as metonymic media and suggesting metaphor characteristics and meaning of Social Network Service.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1348-1351
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• 2009

패킷 재배치(packet reodering)는 전송한 패킷의 순서가 처음과 다르게 뒤섞여 수신지에 도착하는 현상을 의미한다. 패킷 재배치는 불필요한 재전송이나 불필요한 혼잡 제어를 수행하여 TCP의 성능을 저하시킨다. 패킷 재배치에 의한 TCP 성능 저하를 막기 위해 다양한 접근 방법이 소개되었다. TCP-DAD는 기존 TCP에서 3으로 고정된 중복 응답 임계값을 동적으로 조절하여, 잘못된 혼잡 제어를 예방하고 있다. 일반적으로 전송한 패킷의 수가 많을 때, 패킷 재배치를 경험할 확률이 높으며, 패킷 재배치에 의해 잘못된 혼잡 제어가 일어날 가능성 많다. 고속 네트워크 환경에서는 혼잡 윈도우 크기 변화의 폭이 매우 크다는 점을 고려할 때, 중복 응답 임계값을 조절하는 TCP-DAD는 한계가 있다. 본 논문에서는 고속 네트워크 환경에서의 패킷 재배치 현상으로 인한 TCP 성능저하를 완화하기 위한 새로운 알고리즘 TCP-DT를 소개한다. 이는 중복 응답 수에 의존하지 않고 타이머를 통해 혼잡 제어를 수행하는 메커니즘 이다. 본 논문은 NS-2를 사용하여 고속 네트워크 환경에서의 시뮬레이션을 통해 제안한 TCP-DT의 성능 향상을 증명하였다.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.31-40
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• 2005

In the post-genomic era, researches on proteins as well as genes have been increasingly required. Particularly, work on protein-protein interaction and protein network construction have been recently establishing. Most biologists publish their research results through papers or other media. However, biologists do not use the information effectively, because the published research results are very large. As the growth of internet field, it becomes easy to access these research results. It is important to extract information with a biological meaning from various media. Therefore, In this paper, we efficiently extract the protein information from many open papers or other media and construct the database of the extracted information. We build a protein network from the established database and then design and implement various pathway analysis algorithms which find biological meaning from the protein network.

• Journal of the HCI Society of Korea
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• v.6 no.1
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• pp.17-20
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• 2011

The contingency theory of leadership was proposed by F. Fiedler. In his theory, he divided the group into Task oriented and Relationship-oriented people based on work-style by LPC(Least Preffered Co-workers) test. This survey searches significance of interaction usage depending on which group has more aggressive interaction on the address list with mobile phones focusing on the differences between mainfunctions (name, cell phone, group name) and sub-functions (birthday, Photo, E-mail). Itis the hypothesis that the relationship-oriented group has more interaction than the task-oriented group which was identified through the analyzed usage of the address list. Results show that the contingency theory was not appropriately related with the research. Interaction usage by the following task based on Fiedler's contingency theory of leadership isn't related much. However, by discovering the interesting patterns by the test, this research is able to guide human-centered address design directions.