• Journal of Powder Materials
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• v.9 no.4
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• pp.261-266
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• 2002

CAE technology is an integrated tool including all aspects such as powder, binder system, mixing, injection molding, debinding and sintering. Therefore, CAE technology is considered as one of core technologies for PIM industry in the future. Recently many researchers are developing not only CAE software itself but also application procedures of CAE software. In this study, the applications for CAE technology in PIM industry are presented including feedstock mixing effect, several cases of troubleshooting and optimization procedure.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.261-273
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• 2016

Reconfigurable finite impulse response (FIR) filters whose filter coefficients and filter order change dynamically during run-time play an important role in the software defined radio (SDR) systems, multi-channel filters, and digital up/down converters. However, there are not many reports on such reconfigurable designs which can support dynamic variation of filter order and filter coefficients. The purpose of this paper is to provide an architectural solution for the FIR filters to support run-time variation of the filter order and filter coefficients. First, two straightforward designs, namely, (i) single-MAC based design and (ii) full-parallel design are presented. For large variation of the filter order, two designs based on (iii) folded structure and (iv) fast FIR algorithm are presented. Finally, we propose (v) high throughput design which provides significant advantage in terms of hardware and/or time complexities over the other designs. We compare complexities of all the five structures, and provide the synthesis results for verification.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.3
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• pp.99-105
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• 2014

A graphic processing unit (GPU) can perform the same calculation on multiple data (SIMD: single instruction multiple data) using hundreds of to thousands of special purpose processors for graphic processing. Thus, high efficiency is expected when GPU is used for the generation and correlation of satellite navigation signals, which perform generation and processing by applying the same calculation procedure to tens of millions of discrete signal samples per second. In this study, the structure of a GPU-based GNSS simulator for the generation and processing of satellite navigation signals was designed, developed, and verified. To verify the developed satellite navigation signal generator, generated signals were applied to the OEM-V3 receiver of Novatel Inc., and the measured values were examined. To verify the satellite navigation signal processor, the performance was examined by collecting and processing actual GNSS intermediate frequency signals. The results of the verification indicated that satellite navigation signals could be generated and processed in real time using two GPUs.

• Journal of the Korea Society of Computer and Information
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• v.24 no.2
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• pp.35-40
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• 2019

In this paper, we propose a technique to reconstruct the iris image from the iris code by analyzing the process of generating the iris code and calculating it inversely. Iris recognition is an authentication method for authenticating an individual's identity by using iris information of an eye having unique information of an individual. The iris recognition extracts the features of the iris from the iris image, creates the iris code, and determines whether to authenticate using the corresponding code. The iris recognition method using the iris code is a method proposed by Daugman for the first time and is widely used as a representative method of iris recognition technology currently used commercially. In this paper, we restore the iris image with only the iris code, and test whether the reconstructed image and the original image can be recognized, and analyze restoration vulnerability of Daugman's iris code.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1004-1007
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• 2008

2007년 구글에서 공개된 안드로이드는 개방형 모바일 플랫폼으로 모바일 장치를 목표로 한다. 안드로이드 플랫폼은 다양한 모바일 제품에 적용 할 수 있는 구조로 되어 있어 확장이 용이하며 향후 다양한 모바일 장치에 사용될 것으로 생각된다. 이러한 발전성을 고려하여 선행연구 차원에서 연구 될 가치가 충분하다고 판단이 된다. 본 논문에서는 안드로이드 플랫폼에 대표적 홈네트워크 미들웨어인 UPnP와 DLNA에서 명시하는 UPnP for A/V에 준하는 스택을 구현하여 UPnP를 통한 장치들을 검색 및 제어를 하고 DLNA에 준하여 디지털 콘텐츠를 공유, 전송 한다. 또한 안드로이드 플랫폼과 디지털 액자간의 네트워킹을 통해 홈네트워크 플랫폼으로서의 안드로이드 가능성을 확인한다.

• Steel and Composite Structures
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• v.18 no.1
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• pp.165-185
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• 2015

The suspended zipper bracing system is suggested to reduce the flaws of ordinary zipper braced and concentric inverted V braced frames. In the design procedure of suspended zipper bracing systems, columns and top story truss elements are strengthened. This bracing system show different performances and characteristics compared with inverted V braced and ordinary zipper frames. As a result, a different response modification factor for suspend zipper frames is needed. In this research paper, the response modification factor of suspended zipper frames was obtained using the incremental dynamic analysis. Suspended zipper braced frames with different stories and bay lengths were selected to be representations of the design space. To analyze the frames, a number of models were constructed and calibrated using experimental data. These archetype models were subjected to 44 earthquake records of the FEMA-P695 project data set. The incremental dynamic analysis and elastic dynamic analysis were carried out to determine the yield base shear value and elastic base shear value of archetype models using the OpenSEES software. The seismic response modification factor for each frame was calculated separately and the values of 9.5 and 13.6 were recommended for ultimate limit state and allowable stress design methods, respectively.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.16 no.1
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• pp.17-25
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• 2020

Ground-coupled heat pump (GCHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy using efficiency. Although some experimental and simulation works related to performance analysis of GCHP systems for commercial buildings have been done, relatively little has been reported on the performance evaluation of GCHP systems for school buildings. The purpose of this simulation study is to evaluate the performance of a hypothetical GCHP system for a school building in Seoul. We collected various data of building specifications and construction materials for the building and then modeled to calculate hourly building loads with SketchuUp and TRNSYS V17. In addition, we used GLD (Ground Loop Design) V2016, a GCHP system design and simulation software, to design the GCHP system for the building and to simulate temperature of circulating water in ground heat exchanger. The variation of entering source temperature (EST) into the system was calculated with different prediction time and then each result was compared. For 20 years of prediction time, EST for baseline design (Case A) based on the hourly simulation results were outranged from the design criteria.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1342-1350
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• 1999

In this paper, we have developed and analyzed the 2.45GHz microwave RFID system. Which is composed tag and interrogator using custom IC, and we have made the software driving the hardware for the bidirectional data transmission method. Using 3.6V power supply was used, the optimal identification range in the information transmission of the designed microwave RFID system operating at 9,600bps was l0m. In the control circuit of the tag, the low current consumption of 15$mutextrm{A}$ and the tag data transmission rate of 90% when the moving velocity was 80km/h.

• Journal of Astronomy and Space Sciences
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• v.8 no.1
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• pp.99-113
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• 1991

We developed a software system called IODS(ISSA Orbit Determination System), which can predict the orbit of arbitary artificial satellite using the numerical method. For evaluating the orbit prediction accuracy of IODS, the orbital data predicted for the meteorological satellite NOAA-11 and the stationary satellite INTELSAT-V are intercompared with those tracked at the Central Bureau of Meterology and the Kum-San Satellite Communication Station. And the Perturbations affecting the orbit of these artificial satellites are quantitatively analyzed. The orbital variation and the eclipse phenomina due to the shadow are analyzed for a hypothetical geostationary satellite called KORSAT-1 which is assumed to be located in longitude $110^{circ}E$.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.255-262
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• 2011

This paper proposes a grid-tied power conditioning system for fuel cell, which consists of three-phase current-fed DC-DC converter and three-phase PWM inverter. The three-phase current-fed DC-DC converter boosts fuel cell voltage of 26-48 V up to 400 V with zero-voltage switching (ZVS) scheme, while the three-phase PWM(Pulse Width Modulation) inverter controls the active and reactive power supplied to the grid. The operation of the proposed power conditioning system with fuel cell model is verified through simulations with PSCAD/EMTDC software. The feasibility of hardware implementation is verified through experimental works with a laboratory prototype with 1.2 kW proton exchange membrane (PEM) fuel cell stack. The proposed power conditioning system can be commercialized to interconnect the fuel cell with the power grid.