• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3840-3847
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• 2000

Electronic Industries Association has set a standard format called CDIF(CASE Data Interchange Format) for exchanging information between CASE tools from 1991. If data used on a CASE tool is represented in CDIF format, then any other CASE tools can use the data by translating CDlF format into their own format. In order to do so, each CASE vendor must provide a translator program from CDIF to its own data format or from its own data to CDIF format. In this thesis, we have implemented a source code generator for translating CASE data format into CDIF format only if they provide how data is stored. This automatic program generator generates CDIF statements using data format used in CASE tools, meta information about stored data and CDIF meta information. In the thesis, the automatic program generator has been implemented with Java and Oracle DBMS with JOBC interface in Sun O/S environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.4
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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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• v.2 no.4
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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.