• 시스템엔지니어링학술지
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• 제15권1호
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• pp.1-8
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• 2019

Reverse engineering involves examining a system or component so as to comprehend its structure, functionality, and operation. Creation of a system model in reverse engineering can serve several purposes: test generation, change impact analysis, and the creation of a new or modified system. When attempting to reverse engineering a system, often the most readily accessible information is the system description, which does not readily lend itself to use in Model Based System Engineering (MBSE). Therefore, it is necessary to be able to transform this description into a diagram, which clearly depicts the behavior of the system as well as the interaction between components. This study demonstrates how sequence diagrams can be extracted from the systems description. Using MBSE software, the sequence diagrams for the Engineered Safety Features Component Control System (ESF-CCS) of the Nuclear Power Plant are created. Sequence diagrams are chosen because they are a means of representing the systems behavior and the interaction between components. In addition, from these diagrams, the system's functional requirements can be elicited. These diagrams then serve as the baseline of the reverse engineering process and multiple system views are subsequently be created from them, thus speeding up the development process. In addition, the use of MBSE ensures that any additional information obtained from auxiliary sources can then be input into the system model, ensuring data consistency.

• 전자공학회논문지S
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• 제34S권4호
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• pp.57-65
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• 1997

The purpose of this paper is to propose the HMM (hidden markov model) based on multi-observation sequence for the isolated word recognition. The proosed model generates the codebook of MSVQ by dividing each word into several sections followed by dividing training data into several sections. Then, we are to obtain the sequential value of multi-observation per each section by weighting the vectors of distance form lower values to higher ones. Thereafter, this the sequential with high probability value while in recognition. 146 DDD area names are selected as the vocabularies for the target recognition, and 10LPC cepstrum coefficients are used as the feature parameters. Besides the speech recognition experiments by way of the proposed model, for the comparison with it, the experiments by DP, MSVQ, and genral HMM are made with the same data under the same condition. The experiment results have shown that HMM based on multi-observation sequence proposed in this paper is proved superior to any other methods such as the ones using DP, MSVQ and general HMM models in recognition rate and time.

• Journal of the Korean Statistical Society
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• 제26권4호
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• pp.521-530
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• 1997

The new Laplace autoregressive model of order 2-NLAR92) studied by Dewald and Lewis (1985) is extended to the p-th order model-NLAR(p). A necessary and sufficient condition for the existence of an innovation sequence and a stationary ergodic NLAR(p) model is obtained. It is shown that the distribution of the innovation sequence is given by the probabilistic mixture of independent Laplace distributions and a degenrate distribution.

• 인터넷정보학회논문지
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• 제15권4호
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• pp.9-20
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• 2014

대상의 동작을 잘 예측하는 것은 사회적 상호작용과 의사결정 컨텍스트 이해의 핵심이다. 본 연구는 동작 인식 과정에서 인간 뇌 시각인지 과정을 모방한 방법으로 관절 동작의 동작 순서 패턴을 학습하는 컴퓨팅 모델을 제안하였다. 제안 방법의 핵심은 뇌에서 동작 인지 자극을 처리하는 신경생리학적 IT, MT, STS의 피질 기능과 특정 시각 신경 회로 네트워크 기능을 모방하여 비지도 방법으로 동작 순서를 학습한 후 동작을 예측, 인식하는 것이다. 실험을 통해 제안 모델이 어떻게 연속적으로 입력되는 비디오에서 의미있는 동작 스냅샷 뿐 아니라 중요한 동작 패턴을 자동으로 선택하는 지를 제시하였다. 이 핵심 움직임은 학습 네트워크가 정적 시점에서 정지 영상에 함축된 동작을 인식하는지를 증명하는데 이용하는 관절 자세이다. 또한 STS 피질 영역에서 어떻게 정지와 움직임 입력을 통합하는지를 모방하여 학습하고, 학습한 피드백 연결이 차후 동작의 입력 순서를 어떻게 예측하는지를 제시하였다. 네트워크 시뮬레이션을 통해 동작 인식에 대한 제안 모델의 우수성을 입증하였다.

• 한국멀티미디어학회논문지
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• 제7권11호
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• pp.1505-1514
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• 2004

시퀀스 매칭은 시계열 데이터베이스로부터 질의 시퀀스와 변화의 추세가 유사한 데이터 시퀀스들을 검색하는 연산이다. 기존의 대부분의 연구에서는 효과적인 시퀀스 매칭을 위하여 다차원 인덱스를 사용하며, 데이터 시퀀스를 이산 푸리에 변환(Discrete Fourier Transform: DFT)한 후, 단순히 앞의 두 개 내지 세 개의 DFT 계수만을 구성 속성 (organizing attributes)으로 사용함으로써 고차원의 경우 발생하는 차원 저주(dimensionality curse) 문제를 해결한다. 본 논문에서는 기존의 단순한 기법이 가지는 성능 상의 문제점들을 지적하고, 이러한 문제점들을 해결하는 최적의 다차원 인덱스 구성 기법을 제안한다. 제안된 기법은 대상이 되는 시계열 데이터베이스의 특성을 사전에 분석함으로써 변별력이 뛰어난 요소들을 다차원 인덱스의 구성 속성으로 선정하며, 비용 모델(cost model)을 기반으로 한 시퀀스 매칭 비용의 추정을 통하여 다차원 인덱스에 참여하는 최적의 구성 속성의 수를 결정한다. 제안된 기법의 우수성을 규명하기 위하여 실험을 통한기존 기법과의 성능 비교를 수행하였다 실험 결과에 의하면, 제안된 기법은 기존의 기법에 비교하여 매우 큰 성능 개선 효과를 가지는 것으로 나타났다.

• 대한안전경영과학회지
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• 제2권1호
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• pp.77-87
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• 2000

BOM has been widely used to manufacturing, product design and scheduling. There are several bug differences between Manufacturing BOM and Engineering BOM, which cause a lot of problems. A study to integrate both manufacturing BOM and Engineering BOM is researching to solve those problems. Therefore, this research presents a extended Engineering BOM concepts considering assembly sequence model.

• 한국CDE학회논문집
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• 제6권4호
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• pp.263-270
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• 2001

In stamping-die manufacturing, the first step is to build die patterns for lost wax casting process. A recent industry trend is to manufacture the die pattern using 3-axis NC machining. This study identifies technical considerations of the pattern machining caused by the characteristics of Styrofoam material, and proposes technical methods related to establishing a process plan and generating tool paths for optimizing the pattern machining. In this paper, the process plan includes the fellowing three items: 1) deter-mining a global machining sequence-a sequence of profile, top, bottom machining and two set-ups, 2) extracting machining features from a pattern model and merging them, and 3) determining a machining sequence of machining features. To each machining feature, this study determines the machining start point, generates the approach tool path, and proposes a tool path linking method fur reducing the distance of the cutter rapid motion. Finally, a smooth tool path generation and an automatic feedrate adjustment (AFA) method are introduced far raising the machining efficiency.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.60-70
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• 2020

The outfitting design of ships and offshore structures is mainly undertaken in a restricted space. Pipes occupying a large portion of outfitting design are normally manufactured outside the shipyard. This complicated manufacturing process results in frequent delivery delays. Inevitable design modifications and material changes have also resulted in inefficient pipe installation works. In this study, an algorithm is proposed to systematically determine the pipe installation sequence. An accurate and fast algorithm to identify the geometric relationship of piping materials is presented. To improve the calculation efficiency, the interference is gradually examined from simplified to complicated shapes. It is demonstrated that the calculation efficiency is significantly improved with successive geometric operations such as back-face culling and use of bounding boxes. After the final installation sequence is determined, the entire installation process is visualized in a virtual reality environment so that the process can be rendered and understood for a full-scale model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권4호
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• pp.1307-1329
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• 2022

This paper proposes an improved Pseudorandom Sequence Generator (PRSG) based on the concept of modular arithmetic systems with non-integral numbers. The generated random sequence use in various cryptographic applications due to its unpredictability. Here the mathematical model is designed to solve the problem of the non-uniform distribution of the sequences. In addition, PRSG has passed the standard statistical and empirical tests, which shows that the proposed generator has good statistical characteristics. Finally, image encryption has been performed based on the sort-index method and diffusion processing to obtain the encrypted image. After a thorough evaluation of encryption performance, there has been no direct association between the original and encrypted images. The results show that the proposed PRSG has good statistical characteristics and security performance in cryptographic applications.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.288-300
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• 2006

In this paper, we consider a channel ordering problem that seeks to minimize the total interference in mobile radio networks. If a base station receives connection request from a mobile user, one of the empty channels that are fixed to the base station is assigned to the mobile user. Among several channels available, we can choose one that seems to make least interference with other channels assigned to adjacent base stations. However, a pair of channels that are not separated enough do not generate interference if both of them are not simultaneously used by mobile users. That is, interference between channels may vary depending on the channel assignment sequence for each base station and on the distribution of mobile users. To find a channel assignment sequence that seems to generate minimum interference, we develop an optimization model considering various scenarios of mobile user distribution. Simulation results show that channel assignment sequence determined by the scenario based optimization model significantly reduces the interference provided that scenarios and interference costs are properly generated.