• 한국정보처리학회논문지
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• 제7권12호
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• pp.3840-3847
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• 2000

미국의 전자산업협회(Electronic Industries Association)에서는 1991년부터 CASE 도구간의 정보교환을 용이하게 하기 위하여 CDIF (CASE Data Interchange Format) 이라는 표준 형식을 제정해 오고 있다. 각 CASE 도구에서 사용된 데이터를 CDIF 형식으로 변환만 해주면 다른 CASE 도구에서 이를 자신에 맞는 형식으로 변환하여 사용할 수 있다. 이때 각 CASE 도구 공급자는 CDIF 형식으로 변환 혹은 CDIF 형식을 자신에 적합한 형식으로 변환하는 프로그램을 작성하여야 한다. 본 논문에서는 이러한 불편을 해소하기 위해서 CASE 도구 공급자가 각 CASE 도구에서 사용된 자료의 저장형식을 지정하여 주면 CDIF 형식을 지원하는 변환기의 소스코드를 자동으로 생성하는 생성기를 개발하였다. 이 자동 생성기는 CASE 도구에서 사용된 자료의 저장형식, 저장형식에 대한 메타정보, CDIF 메타정보를 입력받아서 CDIF 문장을 생성한다. 본 연구에서 개발한 자동 생성기는 정보저장소에 관계없이 단일화된 인터페이스를 제공하는 JDBC 및 Oracle과 Sun O/S 환경하에서 구현하였다.

• 한국군사과학기술학회지
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• 제5권4호
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• pp.38-48
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• 2002

Some signals, such as in radar system, are transmitted as periodic pulse trains. If more than one pulse train are transmitted over the same communication channel, a problem is to separate them for source identification and extract each pulse train at the receiver. This is known as pulse train deinterleaving. In this paper, we present an approach for deinterleaving the pulse trains and extracting their periods combining the estimation of the frequency of each pulse train by DFT, CDIF/SDIF histogram and Sequence Search technique. Also, we present the result of deinterleaving pulse trains and extracting PRI in the complex environment which multiple signals are interleaved.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.303-314
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• 2009

The present paper shows the results of numerical and experimental modal analyses of Francis runners, which were executed in air and in still water. In its first part this paper is focused on the numerical prediction of the model parameters by means of FEM and the validation of the FEM method. Influences of different geometries on modal parameters and frequency reduction ratio (FRR), which is the ratio of the natural frequencies in water and the corresponding natural frequencies in air, are investigated for two different runners, one prototype and one model runner. The results of the analyses indicate very good agreement between experiment and simulation. Particularly the frequency reduction ratios derived from simulation are found to agree very well with the values derived from experiment. In order to identify sensitivity of the structural properties several parameters such as material properties, different model scale and different hub geometries are numerically investigated. In its second part, a harmonic response analysis is shown for a Francis runner by applying the time dependent pressure distribution resulting from an unsteady CFD simulation to the mechanical structure. Thus, the data gained by modern CFD simulation are being fully utilized for the structural design based on life time analysis. With this new approach a more precise prediction of turbine loading and its effect on turbine life cycle is possible allowing better turbine designs to be developed.