• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.931-934
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• 2000

움직임 추정 및 보상을 위한 방법 중 가장 많이 사용하는 블록 정합 방법은 어떤 평가 함수와 탐색방법(Search Procedure)을 사용했느냐에 따라 그 성능이 달라지게 된다. 본 논문에서는 평가 함수로써 평균 제곱 오차(Mean Squared Error; MSE), 평균 절대값 오차(Mean Absolute Error; MAE), 화소 차분류(Pel Difference Classification: PDC)을, 탐색 방법으로써 전체 탐색 방법(Full Search Method : FSM), 3단계 탐색 방법(Three Step Search : TSS), 대각 탐색 방법(Cross Search Algorithm ;CSA)을 사용하여 이들의 성능을 각각 비교 분석하여 봄으로써 블록 정합 방법을 이용한 움직임 추정에 대한 전반적인 이해를 도모하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2033-2036
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• 2003

002년 기준 우리나라 전체 인구의 약 67%인 3000만명 정도가 인터넷을 사용하고 있으며, 인터넷 사용량 증가 속도 또한 매년 기하급수적으로 늘어나고 있다. 하지만 개방형 네트워크인 인터넷은 개인정보누출, 개인정보 위변조 등과 같은 문제를 내포하고 있으며 이러한 개인 신상정보와 관련한 문제를 해결하기 위하여 PKI기반의 인증서 검증 시스템 즉 공개키 기반의 인증서 검증 시스템이 제안되었다. 본 논문에서는 PKI 기반의 인증서 검증 시스템에서의 인증서 상태 검증 방식 기법인 CRL기반의 인증서 상태 검증 방식과, Delta-CRL 기반의 인증서 상태 검증 방식 OCSP 기반의 인증서 상태 검증 방식에 대해 기술하고 현재 사용되고 있는 인증서 상태 검증 방식의 문제점인 실시간 처리와 네트워크 과부하 문제를 해결하기 위한 방안으로 내부 프로시저와 데이터베이스를 이용한 클라이언트-서버 기반의 인중서 상태 검증 시스템을 제안하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.315-317
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• 2016

소프트웨어의 활용 영역이 점차 넓어지면서 프로그램 코드에 대한 안전성이 훨씬 더 중요해지고 있다. 이에 따라 소프트웨어 품질을 높이기 위한 방법들이 다양하게 제시되어 왔고, 다양한 도구들을 활용한 소프트웨어 품질분석에 대한 관심도 증가하였다. 본 논문에서는 이러한 분석 도구들에 대하여 설명하고 소프트웨어 안전성 분석절차를 제시한다. 분석절차는 시험도구 준비, 시험 수행, 시험결과 검증, 시험결과 산출 단계로 구성되며, 안전성 검사에 효과적임을 확인할 수 있었다.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.47-52
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• 1999

In this paper we propose new approximate method for the performance analysis of closed-loop production system with unreliable machines and random processing times. The approximate method decomposes the production system consisting of K machines into a set of K subsystems, each subsystem consisting of two machines separated by a finite buffer. Then, each subsystem is analyzed by analyzing method n isolation. The population constraint of the closed-loop production system is taken into account by prescribing that the sum of average buffer level in the subsystems is equal to the number of customers in the closed-loop production system,. We establish a set of equations that characterizes unknown parameters of the servers in the subsystems. An iterative procedure is then used to determine the unknown parameters. Experimental results show that these methods provide a good estimation of the throughput.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.87-90
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• 2002

This paper analyzes statistically the relationship between size and balance of text corpus by evaluation of the effect of interview sentences in language model for Korean broadcast news transcription system. Our Korean broadcast news transcription system's ultimate purpose is to recognize not interview speech, but the anchor's and reporter's speech in broadcast news show. But the gathered text corpus for constructing language model consists of interview sentences a portion of the whole, $15\%$ approximately. The characteristic of interview sentence is different from the anchor's and the reporter's in one thing or another. Therefore it disturbs the anchor and reporter oriented language modeling. In this paper, we evaluate the effect of interview sentences in language model for Korean broadcast news transcription system and analyze statistically the relationship between size and balance of text corpus by making an experiment as the same procedure according to varying the size of corpus.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.1001-1008
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• 2012

Non-destructive testing (NDT) is a technique used in science and industry to evaluate the properties of a material without causing damage. In this paper we propose a method for segmenting radiographic images of welding in order to extract the welding defects which may occur during the welding process. We study different methods of level set and choose the model adapted to our application. The methods presented here take the property of local segmentation geodesic active contours and have the ability to change the topology automatically. The computation time is considerably reduced after taking into account a new level set function which eliminates the re-initialization procedure. Satisfactory results are obtained after applying this algorithm both on synthetic and real images.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.3
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• pp.139-146
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• 2003

In this paper, the steady-state operating performance analysis for the three-phase squirrel cage rotor self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) in addition to a constant-speed prime mover (CSPM) is presented on the basis of an effective algorithm based on its frequency-domain equivalent circuit. The operating characteristics of the three-phase SEIG coupled by a VSPM and/or a CSPM are evaluated on line processing under the condition of the electrical passive load parameters variations with simple and efficient computation processing procedure in unregulated voltage control loop scheme. A three-phase SEIG prototype setup with a VSPM as well as a CSPM is implemented for the small-scale clean renewable and alternative energy utilizations. The experimental operating characteristic results are illustrated and give good agreements with the simulation ones.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.453-480
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• 2010

Cryptographic hash functions reduce inputs of arbitrary or very large length to a short string of fixed length. All hash function designs start from a compression function with fixed length inputs. The compression function itself is designed from scratch, or derived from a block cipher or a permutation. The most common procedure to extend the domain of a compression function in order to obtain a hash function is a simple linear iteration; however, some variants use multiple iterations or a tree structure that allows for parallelism. This paper presents a survey of 17 extenders in the literature. It considers the natural question whether these preserve the security properties of the compression function, and more in particular collision resistance, second preimage resistance, preimage resistance and the pseudo-random oracle property.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.279-282
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• 2004

In this paper, we present the methodology of performance testing for web based university resource planning systems. The methodology contains an adequate procedure and workload assessment method. We execute real performance testing to the university resource system during system test stage. To verify the adequacy of the methodology, We compare the result between testing system's hardware utilization and operating system's. The result is nearly the same. Empirical experiments are also shown.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.733-736
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• 2004

본 논문에서는 Oracle과 JSP(Java Stored Procedure)를 이용하여 생산공정 및 실적현황을 보고하고 작업지시가 가능한 온라인 시스템을 개발하였다. 현장과 사무실을 위한 정보전달매체로 LED 전광판을 활용하였다. 기존 전광판을 이용한 시스템에서는 고정된 형식의 정보만을 제공하였으나, 본 논문에서 구축한 시스템은 실시간으로 정보의 내용과 형식을 수정할 수 있다. 이 시스템은 RS6000상에서 Oracle9i와 자바로 개발되었고, 각 전광판과 생산라인에 설치된 조작대는 TCP/IP로 통신한다. 이를 통해 공정감시 및 실적현황 보고를 DBMS에서 통합 관리하며 실시간으로 작업자와 관리자에게 정보를 제공한다.