• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.349-351
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• 2002

베이지안 네트워크는 변수들간의 원인-결과 관계를 확률적으로 모델링하기 위한 도구로서 소프트웨어 사용자의 목적을 추론하기 위해 널리 이용된다. 행동기반 로봇 설계는 반응적(reactive) 행동 모듈을 효과적으로 결합하여 복잡한 행동을 생성하기 위한 접근 방법이다. 행동의 결합은 로봇의 목표, 외부환경, 행동들 사이의 관계를 종합적으로 고려하여 동적으로 이루어진다. 그러나 현재의 결합 모델은 사전에 설계자에 의해 구조가 결정되는 고정적인 형태이기 때문에 환경의 변화에 맞게 목표를 변화시키지 못한다. 본 연구에서는 베이지안 네트워크를 이용하여 현재 상황에 가장 적합한 로봇의 목표를 설정하여 유연한 행동선택을 유도한다. Khepera 이동로봇 시뮬레이터를 이용하여 실험을 수행해 본 결과 베이지안 네트워크를 적용한 모델이 상황에 적합하게 목적을 선택하여 문제를 해결하는 것을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.219-222
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• 2001

본 논문에서는 조류해석에 관한 내용을 웹으로 구현하여 학생들로 하여금 쉽게 학습할 수 있도록 하였고, 풍부한 하이퍼링크로써 궁금한 사항에 대한 즉각적인 On-Line 참조가 되도록 하였다. 웹 문서는 HTML 태그와 자바스크립트를 이용하여 작성하였고 동적이고 양방향적으로 구현할 수 있도록 하는 프로토콜로써 CGI를 사용하여 제공된 입력 데이터를 웹에서 수정해가며 직접 조류계산을 수행할 수 있도록 하였다. 또한 학습자가 결과를 얻고 싶어하는 전력시스템에 대해서는 File Upload를 통하여 결과를 확인할 수 있도록 하였다. File Upload를 위해 qDecoder-7.0 CGI 라이브러리를 이용하였다. 전력 방정식을 풀기 위해 사용된 산법으로는 고속 분할법을 사용하였으며, 모선 서열화와 스파스 프로그래밍 기법 등을 사용하였다. CGI 프로그램에는 C++를 이용하였다.

• Journal of KIISE:Software and Applications
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• v.35 no.4
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• pp.265-279
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• 2008

The idea of using hand gestures for human-computer interaction is not new and has been studied intensively during the last dorado with a significant amount of qualitative progress that, however, has been short of our expectations. This paper describes a dynamic Bayesian network or DBN based approach to both two-hand gestures and one-hand gestures. Unlike wired glove-based approaches, the success of camera-based methods depends greatly on the image processing and feature extraction results. So the proposed method of DBN-based inference is preceded by fail-safe steps of skin extraction and modeling, and motion tracking. Then a new gesture recognition model for a set of both one-hand and two-hand gestures is proposed based on the dynamic Bayesian network framework which makes it easy to represent the relationship among features and incorporate new information to a model. In an experiment with ten isolated gestures, we obtained the recognition rate upwards of 99.59% with cross validation. The proposed model and the related approach are believed to have a strong potential for successful applications to other related problems such as sign languages.

• Journal of KIISE:Software and Applications
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• v.37 no.5
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• pp.378-385
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• 2010

The explosive increase in the use of email has made to need email classification efficiently and accurately. Current work on the email classification method have mainly been focused on a binary classification that filters out spam-mails. This methods are based on Support Vector Machines, Bayesian classifiers, rule-based classifiers. Such supervised methods, in the sense that the user is required to manually describe the rules and keyword list that is used to recognize the relevant email. Other unsupervised method using clustering techniques for the multi-category classification is created a category labels from a set of incoming messages. In this paper, we propose a new automatic email multi-category classification method using NMF for automatic category label construction method and dynamic category hierarchy method for the reorganization of email messages in the category labels. The proposed method in this paper, a large number of emails are managed efficiently by classifying multi-category email automatically, email messages in their category are reorganized for enhancing accuracy whenever users want to classify all their email messages.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1320-1331
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• 2004

A video adaptation system translates the source video stream into appropriate video stream while satisfying the network and client constraints and maximizing the video quality as much as possible. This paper proposes a semi-dynamic video adaptation scheme, in which several intermediate video streams and the information for the measuring of video quality are generated statically. The intermediate video streams are generated by reducing the resolution of the video stream by a power of two several times, and they are stored as the intermediate video streams on the video server. The statically generated information for the input video stream consists of the degrees of smoothness for each frame rate and the degree of frame definition for each pixel bit rate. It helps to dynamically generate the target video stream according to the client's QoS at run-time as quickly as possible. Experimental result shows that the proposed adaptation scheme can generate the target video stream about thirty times faster while keeping the quality degradation as less than 2% comparing to the target video stream that is totally dynamically generated, although the extra storages for the intermediate video streams are required.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.441-450
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• 2002

As the size of embedded system software increase bigger and bigger, and it's complexity is grower and grower, the usage of dynamic memory management scheme such collector also has been increased. Using the garbage collector, however, inherently lead us performance degradation. In order to resolve this kind of performance problem in the Java based embedded system. we introduce an explicit dynamic memory free method to the automated dynamic memory management environment. which can be performed by a programmer. In the worst case, the prosed scheme shows the same performance as the case of that only garbage collector is working, since the unclaimed garbage objects will eventually be collected later by the garbage collector. In the best case. our method is free from any runtime overhead because the applications can be implemented without any intervention of the garbage collector. Although the proposed method can be facilitated with all the existing garbage collection algorithms, it shows an outperform in the case of mark-and-sweep algorithm.

• The Journal of Korean Institute of Information Technology
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• v.17 no.4
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• pp.87-97
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• 2019

SRS was proposed for immediate processing of the meaning of sensor data on mobile devices independent from specific sensor networks and sensor type. However, each time new sensor data is received, sensor data inspection operations are performed repeatedly, and it cause resulting in low performance. App profile-based SRS has been proposed to resolve the problem. The app profile-based SRS has improved the SRS problem through the profile, but has been tested in a virtual simulation environment. After that the test was experimented in a real-time environment, but has not been tested with a variety of dynamic factors. Therefore, this paper experiment considering such as user mobility and sensor density in real-time environment. And this paper also evaluate performance of the App profile-based through analysis of the results of the experiment. As a result, app profile-based SRS is high influence by density and sensor type, and the number of sensor node is not influence.

• Communications of Mathematical Education
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• v.35 no.1
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• pp.119-136
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• 2021

We performed the research and education programs using engineering tools such as Mathematica, Microsoft Excel and GeoGebra for the students in mathematics mentorship program of the institute of science education for the gifted. We used the engineering tools to solve the problems and found the rules by observing the solutions. Then we generalized the rules to theorems by proving the rules. Mathematica, the professional mathematical computation program, was used to calculate and find the length of the repeating portion of the repeating decimal. Microsoft Excel, the spreadsheet software, was used to investigate the Beatty sequences. Also GeoGebra, the dynamic geometric software, was used to investigate the Voronoi diagram and develop the Voronoi game. Using GeoGebra, we designed the Voronoi game plate for the game. In this program, using engineering tools improved the mathematical creativity and the logical thinking of the gifted students in mathematics mentorship program.

• Journal of KIISE
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• v.44 no.2
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• pp.171-178
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• 2017

In this study, we propose an automated unit test generation technique for detecting vulnerabilities of Android kernel modules. The technique automatically generates unit test drivers/stubs and unit test inputs for each function of Android kernel modules by utilizing dynamic symbolic execution. To reduce false alarms caused by function pointers and missing pre-conditions of automated unit test generation technique, we develop false alarm reduction techniques that match function pointers by utilizing static analysis and generate pre-conditions by utilizing def-use analysis. We showed that the proposed technique could detect all existing vulnerabilities in the three modules of Android kernel 3.4. Also, the false alarm reduction techniques removed 44.9% of false alarms on average.

• Journal of KIISE:Software and Applications
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• v.37 no.10
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• pp.760-767
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• 2010

There are many memory leak detection tools. However, programmers, who develop very large programs, tend to avoid testing their programs with memory leak detection tools since these tools require runtime and space overheads. Thus, we present a memory leak detection technique which enables programmers to test their modules in their unit test phase with low overheads. To achieve this goal, we extend the existing cyclic memory allocation technique and evaluate our memory leak detection technique on a tiny DBMS. In our experiments, we find our tool has reasonably low runtime and space overheads and it reports only a small number of false positives.