• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.589-592
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• 2005

In general, the function of intake structure, whether it be a open channel, a fully wetted tunnel, a sump or a tank, is to supply an evenly distributed flow to a pump station. An even distribution of flow, characterized by strong local flow, can result in formation of surface or submerged vortices, and with certain low values of submergence, may introduce air into pump, causing a reduction of capacity and efficiency, an increase in vibration and additional noise. Unfortunately in order to design the sump station, the reasonable code or the standards weren't presented yet in Korea. Thus, some researchers had often referred the HI code, JSME code or CEN code to design the sump station. This study aims to prescribe the standard of sump design which were matched well the Korean pump station. Thus, the HI code and TSJ code would be interpreted fully to Korean language, the part of interpreted clauses of the western codes would be selected to compose the standard.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.423-428
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• 1996

The feasibility study on burning Am-241, 243 and Cm-244 nuclides in a conventional PWR (Pressurized Water Reactor) was carried out by using the TRIFON code that was developed by the Institute of Theoretical and Experimental Physics in Russia in 1992. TRIFON code uses updated ABBN Russian nuclear cross section library. The reference reactor is the Korea nuclear power plant unit 8 (YGN 2). The burning effect of Am-241, 243 and Cm-244 nuclides was studied with UO$_2$(3.5 w/o)fuel assembly and MOX (4.44 w/o) fuel assembly. The loaded mass ratio of Am-241, 243 and Cm-244 nuclides was obtained from the mass ratio of Am-241, 243 and Cm-244 nuclides in 10 year cooling spent fuel with average discharge burnup of 33 GWD/MTU. The effective transmutation rates of Am-241, 243 and Cm-244 nuclides in UO$_2$ fuel assembly were found to be higher than those in MOX fuel assembly. The result from TRIFON code was compared to that from CASMO-3/NEM-3D code system. For more reliable calculation of transmutation for MA(Minor Actinides) more sophisticated decay chain scheme of MA should be investigated and nuclear cross section library of MA should be considerably improved.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.163-170
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• 2011

This study proposed the composition of a new long-code MMSE detector using the pilot channel that demonstrated the most excellent performance under Rayleigh fading in the previous studies. It analyzed and explained how to maintain the stability of the weight vector(introduction to the course of radio waves) in the receiver. In the operation of the receiver system to remove radio interference, the signal vector distortion received in the channel where fading was present achieved good results by compensating for signal errors. When there was distortion, the response characteristics of the received signals were superior to the common matching filter according to the computer simulation. The long-code MMSE receiver proposed in the study was able to prolong the cycle by $16{\times}T_b$ in the fading environment to fulfill the satisfaction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.156-163
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• 2009

In this study, comparative analysis on the back-layer phenomena in the tunnel-fire driven flow is performed using numerical simulation with LES and RANS. FDS(Fire Dynamics Simulator) code is employed to calculate the fire-driven turbulent flow for LES and Smartfire code is used for RANS. Hwang and Wargo's data of scaling tunnel fire experiment are employed to compare with the present numerical simulation. The modeled tunnel is 5.4m(L) ${\times}$ 0.4m(W) ${\times}$ 0.3m(H). Heat Release Rate (HRR) of fire is 3.3kW and ventilation-velocity is 0.33m/s in the main stream. The various grid-distributions are systematically tested with FDS code to analyze the effects of grid size. The LES method with FDS provides an improved back-layer flow behavior in comparison with the RANS (${\kappa}-{\epsilon}$) method by Smartfire. The FDS solvers, however, overpredict the velocity in the center region of flow which is caused by the defects in the tunnel-entrance turbulence strength and in the near-wall turbulent flow in FDS code.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.241-248
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• 1997

This paper presents the development procedure and application of the generic component reliability data base considering the dependency among dependent generic compendia in NPPs (Nuclear Power Plants) PSA (Probabilistic Safety Assessment) under construction or without operating history. We use MPRDP (Multi-Purpose Reliability Data Processor) code developed in KAERI (Korea Atomic Energy Research Institute) based on a PEB (Parametric Empirical Bayesian) procedure to estimate the reliability. The employed model in this study accounts for the relative credibility as well as the dependency among generic estimates. Numerical examples and the part of summarized reliability data table are provided as the application.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.327-330
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• 2011

CFD simulation is widely used in various industries, universities and research centers. In Korea most of the researchers use foreign commercial S/W packages especially in industries. But commercial CFD packages have some problems as limit to source code and very high license foe. So from several years ago open source CFD code has been widely spread as an alternative. But in Korea there are a few users of open source code. Insufficiency of performance validation as for accuracy, robustness, convenience and parallel speed-up is important obstacles of open source code. So we tested some validation cases as to incompressible external aerodynamics and internal flaws and now are doing compressible flaws. As the first stage of compressible flow validation, we simulated Korea next generation high speed train(HEMU). It's running condition is 400km/hr and maximum Mach number reaches up to 0.4. With the high speed train we tested accuracy, robustness and parallel performance of open source CFD code OpenFOAM Because there isn't experimental data we compared results with widely used commercial code. When use $1^{st}$ order upwind scheme aerodynamic forces are very similar to commercial code. But using $2^{nd}$ order upwind scheme there was some discrepancy. The reason of the difference is not clear yet. Mesh manipulation, domain decomposition, post-processing and robustness are satisfactory. Paralle lperformance is similar to commercial code.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.541-544
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• 2003

In this paper, we analyzed a physical layer of W-CDMA system and a performance of a downlink of W-CDMA system by using the space-time code by computer simulation over the ITU-R realistic channel model. From the results of the simulation, we note that the increase of multi-path components affects the improvement of the system performance because of the effect of the RAKE receiver.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.4
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• pp.334-341
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• 2023

The purity of hydrogen finally purified in the hydrogen purification process system is greatly influenced by the uniformity of the purification temperature of the dry tower. A in-house code that can be easily used by field designers has been developed to predict the capacity of the appropriate heat source and the time to reach the temperature of the dry tower. A code was developed to predict unsteady heat transfer using Visual Basic for Applications. To verify the developed code, a grid independence test was performed, and finally, calculations were performed for two cases. In the first case, the time for the temperature of the heater jacket to reach 360℃ was about 1,400 seconds when the supply heat source was 1,000 W. And in the second case, the time for the temperature of the heater jacket to reach 360℃ was about 710 seconds when the supply heat source was 2,000 W. It was confirmed that the developed code well describes the actual test data of the regeneration process of adsorption and desorption, and it is judged that the code developed in the design process of various capacity systems will be effectively applied to the heat capacity calculation in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.272-279
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• 2006

In this paper, we evaluate the performance of frame synchronization words of pilot bit patterns which are used for the channel estimation and frame synchronization confirmation in W-CDMA(Wide band Code Division Multiple Access) system. W-CDMA system also uses compressed mode to make measurements from another frequency without a full dual receiver terminal. It is confirmed by using computer simulation that the proposed frame synchronization words also maintain the frame synchronization property in the compressed mode by using the complementary mapping relationship of preferred pair ROC(Receiver Operating Characteristic) curves with probability of detection and false alarm are used to analized the performance of the proposed frame synchronization words by using the various detection metrics such as LLRT(Log Likelyhood Ratio Test), GLRT(Generalied Likelyhood Ratio Test), soft and hard correlation tests in AWGN and Rayleigh fading channels. It is expected that the research results fer the performance of pilot bit patterns of this paper can be useful reference for the design and implementation of frame synchronization in 3rd generation W-CDMA system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.389-390
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• 2012