• International Journal of Naval Architecture and Ocean Engineering
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• 제8권5호
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• pp.496-510
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• 2016

Simulation technology is a type of shipbuilding product lifecycle management solution used to support production planning or decision-making. Normally, most shipbuilding processes are consisted of job shop production, and the modeling and simulation require professional skills and experience on shipbuilding. For these reasons, many shipbuilding companies have difficulties adapting simulation systems, regardless of the necessity for the technology. In this paper, the data model for shipyard production simulation model generation was defined by analyzing the iterative simulation modeling procedure. The shipyard production simulation data model defined in this study contains the information necessary for the conventional simulation modeling procedure and can serve as a basis for simulation model generation. The efficacy of the developed system was validated by applying it to the simulation model generation of the panel block production line. By implementing the initial simulation model generation process, which was performed in the past with a simulation modeler, the proposed system substantially reduced the modeling time. In addition, by reducing the difficulties posed by different modeler-dependent generation methods, the proposed system makes the standardization of the simulation model quality possible.

• International Journal of Advanced Culture Technology
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• 제10권2호
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• pp.233-239
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• 2022

Recently, research is being conducted on the rapid service provision and reliability of the instance-based rather than the existing IP-based structure. Research is mainly conducted through Block cloud, a platform that combines service-centric networking (SCN) and blockchain. In addition, the Internet of Things network has been proposed as a fog computing environment in the structure of the existing cloud computing. Fog computing is an environment suitable for real-time information processing. In this paper, we propose a new Internet network structure based on fog computing that requires real-time for rapid processing of IoT services. The proposed system applies IoTA, the third-generation blockchain based on DAG, to the block cloud. In addition, we want to propose a basic model of the object block chain and check the application services of electric vehicles.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.61-69
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• 2010

This paper presents a study of a DFIG wind power generation system for real-time simulations. For real-time simulations, the Real-Time Digital Simulator (RTDS) and its user friendly interface simulation software RSCAD are used. A 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. The stator-flux oriented vector control scheme is applied to the stator/rotor side converter control, and the back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for a realistic, reliable and accurate simulation analysis. Block diagrams, a mathematical presentation of the DFIG and a control scheme of the stator/rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.

• 제어로봇시스템학회논문지
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• 제21권9호
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• pp.827-835
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• 2015

In this paper, we present the implementation method of Dynamic Matrix Control(DMC) block for use with a Rapid Control Prototyping(RCP) system and consider the speed control of a DC motor using the developed DMC block. Firstly, we briefly introduce a lab-built RCP system. Secondly, we present a method for implementing a DMC block using C-language, which enables the DMC algorithm to be represented in a library block that can be used in a Simulink environment. Finally, we use the developed DMC block for the speed control of a DC motor, through which we show that the DMC-based control system can be easily implemented and applied to the real-time control of systems with relatively fast dynamics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.494_495
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• 2009

This paper presents a study of DFIG wind power generation system for real-time simulation. For real-time simulation, the real-time digital simulator (RTDS) and its user friendly interface simulation software (RSCAD) are used. 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. Stator-flux oriented vector control scheme is applied to stator, rotor side converter control, and back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for realistic and accurate simulation analysis. Block diagrams for DFIG and control scheme of stator, rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.

• 방송공학회논문지
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• 제16권6호
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• pp.969-976
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• 2011

본 논문에서는 선형분산행렬(linear dispersion)을 이용한 하이브리드 MIMO(multi-input multi-output) 시스템을 적용하여 차세대 지상파 DTV 시스템을 구현하기 위한 새로운 전송 기법을 제안한다. 유럽형 방송 시스템인 DVB-T2에서는 수신 성능을 향상시키기 위하여 STBC(space time block code) 기법을 선택적으로 적용하였다. 그러나 STBC 기법은 송신 안테나에 비례하여 전송량이 증가하지 않는 단점이 있다. 이러한 STBC의 단점을 극복하기 위하여 전송단에 여러 개의 서로 다른 STBC 전송 행렬을 배치하는 하이브리드 STBC 기법이 사용된다. STBC 기법보다 향상된 수신 성능을 가지는 선형분산행렬을 하이브리드 형태로 구성하여 전송량 및 수신 성능을 향상시켰다. 제안한 하이브리드 MIMO 기법과 기존의 하이브리드 STBC 기법의 성능을 컴퓨터 실험을 통하여 비교분석하였다.

• 한국멀티미디어학회논문지
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• 제25권7호
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• pp.922-931
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• 2022

Recently, the need for health information management platforms has been increasing for efficient medical and IT technology research. However, health information is requiring security management by law. When permissioned blockchain technology is used to manage health information, the integrity is provided because only the authenticated users participate in bock generation. However, if the blockchain server is attacked, it is difficult to provide security because user authentication, block generation, and block verification are all performed on the blockchain server. In this paper, therefore, we propose a Health Information Management Server, which uses a permissioned blockchain algorithm and asymmetric cryptography. Health information is managed as a blockchain transaction to maintain the integrity, and the actual data are encrypted with an asymmetric key. Since using a private key kept in the institute local environment, the data confidentiality is maintained, even if the server is attacked. 1,000 transactions were requested, as a result, it was found that the server's average response time was 6,140ms, and the average turnaround time of bock generation was 368ms, which were excellent compared to those of conventional technology. This paper is that a model was proposed to overcome the limitations of permissioned blockchains.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 추계 학술대회논문집
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• pp.152-156
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• 2001

Three dimensional orthogonal grid generation is able to control effectively the grid spacing near the boundaries, but there are some difficulty to meshing complex geometry. The mesh complex geometry by orthogonal grid generation method must divide block of geometry It is required a careful skill, and long time. Its also difficulty to make unstructured mesh on complex geometry. Particularly, three dimensional geometry must have more time and effort. Recently, there have been growing interests in mesh generation of complex grometry, aslike an automobile headlamp, the heart. The method of easily meshing complex geometry is resarched to solve them. We suggest octree grid into one among these methods. As octrce grid is automaticaly adapted at the boundaries by determine the level operations to control the grid spacing near the boundaries are unnecessary. In this paper we showed throe dimensional mesh generation, and heat-flow analysis on the octree mesh.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3608-3628
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• 2017

Several block cipher modes of operation have been proposed in the literature to protect sensitive information. However, different security analysis models have been presented for attacking them. The analysis indicated that most of the current modes of operation are vulnerable to several attacks such as known plaintext and chosen plaintext/cipher-text attacks. Therefore, this paper proposes a secure block cipher mode of operation to thwart such attacks. In general, the proposed mode combines one-time chain keys with each plaintext before its encryption. The challenge of the proposed mode is the generation of the chain keys. The proposed mode employs the logistic map together with a nonce to dynamically generate a unique set of chain keys for every plaintext. Utilizing the logistic map assures the dynamic behavior while employing the nonce guarantees the uniqueness of the chain keys even if the same message is encrypted again. In this way, the proposed mode called SPCBC can resist the most powerful attacks including the known plaintext and chosen plaintext/cipher-text attacks. In addition, the SPCBC mode improves encryption time performance through supporting parallelized implementation. Finally, the security analysis and experimental results demonstrate that the proposed mode is robust compared to the current modes of operation.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제3권10호
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• pp.377-382
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• 2014

모바일 통신과 사물 인터넷(IoT) 환경에서 시간에 따른 데이터의 분석 기술은 주로 의미 있는 정보를 찾기 위해 수집 된 데이터에서 의미있는 패턴을 추출하기 위해 사용된다. 기존의 데이터 마이닝을 이용한 분석 방법은 데이터 수집이 어렵고 시간의 경과와 관련된 시계열 데이터의 변경을 반영하기 위해 완료 상태에 기초하여 해석되어야 한다. 이러한 패턴의 다양성, 대용량성, 연속성 등의 여러 가지 특성을 가진 데이터 스트림의 분석을 위한 방법으로 멀티 블록 스트리밍 데이터 분석(AM-MBSD) 방법을 제안한다. 의미 있는 데이터 추출을 위해 멀티 블록 스트리밍 데이터의 패턴을 추출하고 추출된 연속적 데이터를 여러 개의 블록으로 정의하고 제안 방법의 검증을 위해 각 데이터 블록의 데이터 패턴 생성 시간, 주파수를 수집하고 시계열 데이터를 분석, 실험하였다.