• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.1236-1238
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• 2022

JVET 은 최신 비디오 부호화 표준인 VVC(Versatile Video Coding) 표준화를 완료한 후, VVC 보다 더 높은 압축 성능을 가지는 새로운 표준기술 탐색을 진행하고 있으며, 이를 위하여 참조 소프트웨어 ECM(Enhanced Compression Model)을 개발하고 있다. 현재 ECM4.0 에는 다양한 후보 구성 및 예측 성능 개선 기법을 추가하여 기존 VVC 의 GPM(Geometric Partitioning Mode)을 확장한 GPM-MMVD(GPM with merge MV differences), GPM-TM(GPM with template matching) 등을 채택하고 있다. 본 논문에서는 ECM 에 채택된 확장된 GPM 기술들의 각 기술 별 선택 빈도를 분석하고 이를 바탕으로 보다 효율적인 GPM 확장 모드 시그널링 방식을 제안한다. 또한 후보 탐색 알고리즘을 간소화한 복잡도 감소 기법을 제시한다. 실험결과 제안하는 시그널링 기법은 ECM4.0 대비 Y와 Cb, Cr 에서 각각 0.02%, 0.16%, 0.09% BD-rate 부호화 성능 향상을 보였고 GPM 인덱스 탐색 간소화 기법은 ECM4.0 대비 Y 와 Cr 에서 각각 0.02%, 0.18% BD-rate 부호화 성능 향상을 보였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.1239-1240
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• 2022

JVET 은 VVC(Versatile Video Coding) 표준화 완료 이후 보다 높은 압축 성능을 갖는 차세대 비디오 코덱의 표준 기술을 탐색하고 있으며 ECM(Enhanced Compression Model) 참조 소프트웨어를 통해 제안된 알고리즘의 성능을 검증하고 있다. 현재 ECM 에서는 정해진 순서에 의해 병합(Merge) 후보를 구성하고 템플릿 매칭(template matching)을 통하여 후보들의 순서를 재배열하는 ARMC(Adaptive Reordering of Merge Candidate) 기법을 채택하고 있다. 본 논문은 ARMC 의 병합 후보의 선택 빈도 분석을 바탕으로 정규 병합(regular merge) 후보 수를 확장하여 구성하고, 실제 탐색에 사용되는 최종 후보의 수를 제한하는 효율적인 ARMC 후보 구성 기법을 제안한다. 실험결과 ECM 4.0 대비 Cb 와 Cr 에서 0.12%, 0.19% 비디오 부호화 성능을 확인하였다.

• The Korean Journal of Applied Statistics
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• v.16 no.2
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• pp.305-319
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• 2003

This paper provides a non-Bayesian method based on the expanded EM algorithm for segmenting the magnetic resonance images degraded by bias field. For the images with the intensity as a pixel value, many segmentation methods often fail to segment it because of the bias field(with low frequency) as well as noise(with high frequency). Our contextual approach is appropriately designed by using normal mixture model incorporated with Markov random field for noise-corrective segmentation and by using the penalized likelihood to estimate bias field for efficient bias filed-correction.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.138-146
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• 2001

The guided missile carries its own tracking radar to detect its target under noisy environments. The enemy warship uses the anti-missile electric-countermeasure(ECM) technique, such as chaff or decoy, so that the approaching guided missile could not destroy it. In this paper we propose the identification algorithm of a target signal when the enemy warship uses the chaff and decoy to deceive the guided missile. In the proposed scheme the mean square errors(MSE) between the received signals and the reference decoy signal, and between the received signals and the reference chaff signal are calculated. Then, the received signal which results in the maximum MSE is regarded as a warship signal. The performance of the proposed algorithm is verified through the computer simulation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.134-140
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• 2015

A control program of an engine control module (ECM) was developed, and its control performance was verified on a 750Ps marine diesel engine. The control method was designed for an engine rotational speed control system. For ECM hardware, the commercial rapid control prototype (RCP) ECM was used. The programming tool for control algorithm development was the MatLab/Simulink. The main control algorithm assembled many control models as engine cranking, run, and stall. Each model has sub-models to input/output control signals. The target engine speed was input signal from a speed control lever, and control output signal of the ECM was sent to the unit-injectors for fuel injection. The engine test was performed under various conditions of engine rotational speeds and dynamometer loads. The test results show that the control function of the ECM is suitable for electrical marine diesel engines.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.97-100
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• 2005

A new model-based clustering algorithm is proposed. The idea starts from the assumption that observations are realizations of Gaussian processes and so are correlated. With a special covariance structure, the posterior probability that an observation belongs to each cluster is computed using the ECM algorithm. A preliminary result of small-scale simulation study is given to compare with the k-means clustering algorithms.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1995.11a
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• pp.341-364
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• 1995

본 고에서는 DAVIC 에서 권고 중인 VOD (video-on-demand) 시스템에 대한 액세스 제어 기법을 분석하고, 이를 바탕으로 국내 VOD 시스템에 적용 가능한 액세스 제어 기법을 제시한다. 이를 위하여 DAVIC 의 VOD 시스템에서의 보안 기법을 분석하고, 보안 시스템을 위한 참조 모델과 요구되는 서비스 및 보안 메카니즘을 분석한 후, 국내 VOD 시스템에 적용 가능한 액세스 제어 시스템 실현 방안과 정보보호 메카니즘을 제시한다. 그리고 방송용 서비스에 적용 가능한 ECM 채널을 DES, MD5, 그리고 RSA 알고리즘을 이용하여 C 언어로 구현하고 관련 동작을 시뮬레이션한다. 시뮬레이션 결과 ECM 채널이 정상 동작됨을 확인한다. 제시된 방안은 국내 VOD 시스템 실현시 유용하게 활용될 수 있다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.10
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• pp.1093-1100
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• 2015

Since the security of RSA cryptosystem depends on the difficulty of factoring integers, it is the most important problem to factor large integers in RSA cryptosystem. The Lenstra elliptic curve factorization method(ECM) is considered a special purpose factoring algorithm as it is still the best algorithm for divisors not greatly exceeding 20 to 25 digits(64 to 83 bits or so). ECM, however, wastes most time to calculate $M{\cdot}P$ mod N and so Montgomery and Koyama both give fast methods for implementing $M{\cdot}P$ mod N. We, in this paper, further analyze Montgomery and Koyama's methods and propose an efficient algorithm which choose the optimal parameters and reduces the number of multiplications of Montgomery and Koyama's methods. Consequently, the run time of our algorithm is reduced by 20% or so than that of Montgomery and Koyama's methods.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.341-342
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• 2016

본 논문에서는 고용량 및 고방전 리튬-이온($LiCoO_2$)원통형 (cylindrical)셀의 방전전류크기 및 SOC 구간에 따른 등가회로 파라미터의 특성을 비교 분석해보고 SOC 추정시 모델링 및 알고리즘 차별화의 필요성을 제시하고자 한다.

• Communications for Statistical Applications and Methods
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• v.18 no.3
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• pp.391-401
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• 2011

Consider a cluster, so called a 'son cluster', whose mean and variance is composed of the means and variances of both clusters called as a 'father cluster' and a 'mother cluster'. In this paper, a method for identifying each of three clusters is provided by modeling the relationship with father and mother clusters. Under the normal mixture model, the parameters are estimated via EM algorithm. We were able to overcome the problems of estimation using ECM approximation. Numerical examples show that our method can effectively identify the three clusters, so called a 'family of clusters'.