• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.5
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• pp.44-51
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• 2009

In this paper, an air conditioner peak power control system using electric power line communication has been developed. The air conditioner power control system using RS-485 communication method is hard to install on the existing buildings due to difficulty in cabling, and the system using wireless communication methods has a weak point of not being able to be used in close space, while the developed system has its own advantages of overcoming the above mentioned obstacles. In addition, the system is extended to support not only single-phase electricity system but also three-phase four-wire electricity system, and therefore can be installed anywhere in the domestic environment. The system also has enhanced the ease of deployment, operational stability and economical efficiency by compact circuit design. Considering the current state requiring the energy sayings, the system would greatly contribute to the widespread use of the air conditioner power control system. The superiority in the performance and stability of the system has been proved by the design verification of each component such as remote air conditioner controller, electric power line gateway and so on, and the field test of the whole system.

• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.493-499
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• 2010

The next generation domestic high speed railway system is a power dispersed type and uses vector control method for motor speed control. Nowadays, inverter driven induction motor system is widely used. However, recently PMSM drives are deeply considered as a alternative candidate instead of an induction motor driven system due to their advantages in efficiency, noise reduction and maintenance. In this paper, the maximum torque control approach is presented for the IPMSM drives with reluctance torque. The applied control method uses maximum torque control per ampere technique. Simulation programs based on Matlab/Simulink are developed. Finally the designed system is verified by simulation and their characteristics are analyzed by the simulation results.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.11
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• pp.39-47
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• 1998

This paper describes high-speed pipelined memory architecture for a shared buffer ATM switch. The memory architecture provides high speed and scalability. It eliminates the restriction of memory cycle time in a shared buffer ATM switch. It provides versatile performance in a shared buffer ATM switch using its scalability. It consists of a 2-D array configuration of small memory banks. Increasing the array configuration enlarges the entire memory capacity. Maximum cycle time of the designed pipelined memory is 4 ns with 5 V V$\_$dd/ and 25$^{\circ}C$. It is embedded in the prototype chip of a shared scalable buffer ATM switch with 4 x 4 configuration of 4160-bit SRAM memory banks. It is integrated in 0.6 $\mu\textrm{m}$ 2-metal 1-poly CMOS technology.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.81-81
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• 2009

최근 휴대폰, 노트북 등과 같은 소형 멀티미디어 기기의 사용이 증가함에 따라 전자 패키징 산업은 경박단소화를 요구하고 있습니다. 더불어 전기적 신호의 손실을 줄이기 위해 전기, 전자산업체에서는 가볍고 굴곡성이 우수한 연성인쇄회로기판(Flexible Printed Circuit Board, FPCB)과 가격이 싸고 신뢰성이 입증된 경성인쇄회로기판(Rigid Printed Circuit Board, RPCB)의 전극간 접합에 많은 관심을 보이고 있습니다. 기존에 연성인쇄회로기판과 경성인쇄회로기판을 접합하는 방식으로는 connector를 이용한 체결법이 사용되고 있지만 완성품의 부피가 커지고 자동화 공정이 힘들며 I/O 개수가 제한적이어서 신호전달에 취약한 단점이 있습니다. 또한, 최근 FPCB를 RPCB에 접합하는데 interconnection으로 이방성 도전 필름(Anisotropic conductive film, ACF) 또는 비전도성 필름(Non-conductive film)이 널리 사용되고 있습니다. 하지만 필름의 가격이 비싸고, 낮은 전기 전도도를 보이며, 신뢰성 특성이 낮다는 단점을 가지고 있습니다. 본 실험에서는 기존의 connector 방식과 접착 필름을 이용한 방식을 대체하기 위하여 솔더를 interlayer로 이용하여 열과 압력으로 접합하는 방법에 대하여 연구하였습니다. 실험에 사용된 솔더의 조성은 Sn-3.0Ag-0.5Cu (in wt%)이고, RPCB와 FPCB의 표면처리는 ENIG로 하였습니다. 접합 온도와 접합 시간에 따라 최적의 접합 조건을 도출하고자 하였고, 접합된 시편을 가지고 신뢰성 테스트를 진행하였습니다. $85^{\circ}C$/85% 고온고습 시험과 고온 방치 시험을 통하여 접합부의 신뢰성을 테스트 하였고, 90도 Peel test로 기계적 접합 강도를 측정하였고, 파괴 단면을 Scanning Electron Microscopy (SEM), Energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS)로 분석하였습니다.

• Geotechnical Engineering
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• v.13 no.4
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• pp.25-36
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• 1997

To increase the bearing capacity of existing auger-drilled piles and decrease the noise and vibration during the installation of the piles, Spirally-reamed and Under-reamed auger trilled piling methods were developed. Field tests were performed to verify the inurement degree of bearing capacity and the constructional possibility of the new augerdrilled piling methods. The test results showed that the bearing capacity of the new augertrilled piles was fairly improved by the grooves of piles, and the skin friction was affected by the groove height and spacing between grooves. It was found that the skin friction takes the great part of total bearing capacity in auger drilled Biles, i.e. 74~80% in case of the existing methods and 81~86% in case of these methods. Moreover, the settlement of spirally-reamed and under reamed piles was smaller than that of the existing augerdrilled pile for the same loading state.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.69-76
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• 2010

The majority of research that has been performed on cracking potential of concrete by shrinkage has assumed that concrete acts as a homogeneous material. However, with this approach, it is not able to evaluate the micro-cracking behavior in concrete due to autogenous shrinkage under unrestrained boundary condition (free boundary condition) nor to understand the cracking behavior properly because of the heterogeneous nature of concrete. To better understand the micro-cracking behavior of concrete induced by autogenous shrinkage, series of experiments were performed measuring the length change and acoustic emission energy. As an analytical approach, this research uses an object oriented finite element analysis code (OOF code) to simulate the behavior of the concrete on a meso-scale. The concrete images used in the simulations were directly obtained from mortar samples. From the experiments and simulation results, it was able to better understand the micro-cracking behaviour of concrete due to shrinking of paste phase and internal restraint by aggregates.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.133-140
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• 2020

The IISS(Integrated Interface Storage System) software uses communication methods such as DSS(Data Sharing Service), UDP to perform the function of sending all messages from the Combat Management System to the analytical computer. Because IISS software handles all message used in the Combat Management System, the source code is large and has a highly dependent feature on message changes. Modification of software is a task that requires a lot of labor, such as series of software reliability test. so research has been conducted to reduce software development costs, including minimizing software modifications. In this paper, We study the method of messages receiving and architectural structure improvement to minimize reliance on message changes in the Combat Management System and improve the modifiability. Reduced message dependency by changing the way DSS and UDP protocols are communicated to Packet Sniffing. In addition, Factory Method Pattern were applied to improve the software design. Test comparing existing software and development elements have confirmed that the software has improved its modifiability and reuse.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.45-51
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• 2008

HID(High Intensity Discharge) search lamp for shipment requires a high open circuit and output current compare than vehicle. This paper presents a soft-start open circuit voltage and constant current sequence control method for 2.5[kW] HID search lamp. The proposed method controls the opal circuit voltage and discharge current of HID lamp according to ignition signal with a simple 8-bit micro-processor and PWM device. For the stable control of lamp, micro-processor checks the output voltage and current. And the checked signals are compared with ignition signal and changes the control mode for stable operation. An ignition signal and micro-processor change the control mode from open circuit voltage contort to constant current control. The proposed control scheme is verified from experimental tests of 2.5[kW] HID search lamp for shipment.

• Journal of Animal Environmental Science
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• v.11 no.1
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• pp.61-70
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• 2005

A total of 4 trials were conducted to evaluate the nutritional value of food waste-byproduct feeds mixture(FWM) rotary drum-pasteurized and cured, to trace the nutritional flow according to the processing stages and finally to determine the optimal mixing formulation of feed ingredients for the growing pigs. Pasteurizing and curing FWM using a rotary drum drier resulted in little change in chemical composition and 8 to $15 \%$ of dry matter losses. Chemical change was affected by different feed ingredients used in each trial. Curding of FWM was caused probably by high moisture content, starch content and(or) physical characteristics of feed ingredients. The optimal mixing ratio of feed ingredients was food waste 45 : deepstacked broiler litter 10 : bakery by-product 22.5 barley bran 22.5. In conclusion, FWM rotary drum-pasteurized and cured had a satisfactory feed-nutritional value far growing pigs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.119-125
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• 2022

In this paper, we present design, implementation and test results of CTM (Chirp Transceiver Module) EM (Engineering Model) for C-Band SAR (Synthetic Aperture Radar) Payload. The CTM is designed to operate dual frequency scan method that simultaneously operate two frequencies in each 50MHz bandwidth to achieve 120Km swath with 10m resolution at about 500Km altitude. The CTM used radiation tolerant RTG4 FPGA for space environment, and implemented with the Parallel DDS (PDDS) method which uses a small memory capacity compared to the memory-map method. Test results show high purity chirp signal generation and excellent IRF performance from received chirp signal after direct digital conversion.