• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.559-562
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• 1999

In this paper, we developed on internet based assembly information display system for the blind. The system is consist of hardware and software. The hardware is consist of a voice synthesis device and a tactile display for character information, and the software is consist of internet web browser for the blind and braille program. The tactile-device system consists of a control unit, pin array, pin generator, serial port, and a power supply. The pin exerted by a electromagnetic method, solenoid. The internet web browser separates the character and image from internet web page, and character information in the web page is converted to braille and fed to sound system. Also the image in the web page can be printed developed tactile display. As the results of experiment, the blind could access the internet web site by using this system and understand various internet information.

• 대한전자공학회논문지SD
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• 제43권4호
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• pp.31-37
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• 2006

광 신호 제어 시스템에서 사용되는 광/안테나 연결회로의 제작 간소화에 대한 중요성이 지속적으로 대두되고 있다. 이를 위하여, 본 논문에서는 광섬유로 제작된 새로운 형태의 photonic 안테나 설계에서 광 도전 효과에 기인한 광섬유와 슬롯 결합형 마이크로 스트립 안테나 사이의 광 결합효율을 수치 해석적으로 분석하였다. 결합특성을 정확하게 분석하기 위하여 원통형, 평면형 전송구조들이 결합할 때 발생하는 불연속 특성을 포함한 새로운 모드 전송선로 이론을 정의하였다 분석결과, 서로 다른 두 전송구조에서의 최대 전력전송은 그 결합영역에서 전파하는 정확한 두 모드들의 전송전력이 균등하게 분배되는 새로운 지점에서 발생함을 보였다.

• 한국통신학회논문지
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• 제40권8호
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• pp.1469-1476
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• 2015

본 논문은 원형배열 안테나를 사용하는 무선 메쉬 네트워크 환경에서 코드북을 이용한 다중 섹터 빔 형성시 섹터간 SIR 향상 빔 선택 알고리즘을 제안한다. 제안된 빔 선택 알고리즘은 피드백 되는 코드북 인덱스 조합에 따라 상호간 SIR을 향상시키는 빔 선택방법과 QoS를 보장하는 방법에 관한 내용이다. 전산 모의 실험을 통해 노드들이 섹터경계에 있을 경우 제안한 방법이 기존의 코드북 선택 방법보다 SIR이 4.42dB 우수함을 보였다. QoS를 위해 PF를 적용할 경우 기존보다 SIR이 1.70dB만큼 향상됨을 보였고 사용자간 QoS도 만족시킴을 보였다.

• Journal of Power Electronics
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• 제16권1호
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• pp.190-204
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• 2016

An active front end (AFE) is required for a three-phase induction motor (IM) fed by a voltage source inverter (VSI), because of the increasing need to derive quality current from the utility end without sacrificing the power factor (PF). This study investigates a proportional-plus-integral (PI) controller based AFE topology that uses a super-lift converter (SLC). The significance of the proposed SLC, which converts rectified AC supply to geometrically proceed ripple-free DC supply, is explained. Variations in several power quality parameters in the intended IM drive for 0% and 100% loading conditions are demonstrated. A simulation is conducted by using MATLAB/Simulink software, and a prototype is built with a field programmable gate array (FPGA) Spartan-6 processor. Simulation results are correlated with the experimental results obtained from a 0.5 HP IM drive prototype with speed feedback and a voltage/frequency (V/f) control strategy. The proposed AFE topology using SLC is suitable for three-phase IM drives, considering the supply end PF, the DC-link voltage and current, the total harmonic distortion (THD) in supply current, and the speed response of IM.

• 전기학회논문지
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• 제66권12호
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• pp.1804-1809
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• 2017

A data acquisition (DAQ) system based on oscilloscope was developed and evaluated for radiation detector. The dedicated LabVIEW program that perform the oscilloscope control and the data process was developed. Triggered events for each analog channel were acquired and the output signals were subsequently digitized and recorded for offline processing. Radiation pulse generation circuit was developed to evaluate the intrinsic characteristics of DAQ system. Energy linearity and energy resolution performances were assessed by voltage-peak channels and FWHM obtained from Gaussian fit, respectively. Radiation detector consists of LYSO and GAPD array. The 16 output signals were multiplexed by the RCD networks, and they were fed into the custom-made preamplifiers. Voltage-peak channels was linearly changed as a function of input voltage and the estimated coefficient of determination ($R^2$) was 0.999. No considerable changes in voltage resolution were observed. All 16 crystals were clearly identifiable on the resulting flood image and the mean energy resolution was ~15.1%. This study demonstrated that it is feasible to develop the DAQ system based on oscilloscope and LabVIEW program for radiation detector and the proposed approach offers opportunities to build simple DAQ system in various radiation measurement field.

• 대한한방부인과학회지
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• 제20권3호
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• pp.65-80
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• 2007

Purpose: This study is to examine anti-obesity effect and cytotoxicity of the long-term oral administration of Ephedra Sinica(Ma-hwang, ES) Methods: Using diet-induced obesity C57BL/6 mouse model, anti-obesity effect and DNA chip expression and cytotoxicity of the long-term oral administration of this herbal extract were investigated. Results: The herbal extract treated groups were arrested in weight increment only when they were lodged together. Such effects were abolished when they kept individually. ES fed mice behaved very rudely and violently. On the basis of histological studies of liver tissues and also in vitro cytotoxicity tests of the liver and kidney cell lines, no significant toxicity was found by 14 weeks of ES treatments. However, we found significant changes in gene expression profile in ES treated group by micro-array analysis. In case of ES group, up-regulated genes were 113 and down-regulated were 120. Some of lipid metabolism related genes also significantly changed in treatment groups. Conclusion: ES had effects of increasing the basal metabolic rate by stimulating the sympathetic nervous systems.

• 대한방사선기술학회지:방사선기술과학
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• 제31권3호
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• pp.287-292
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• 2008

방사선 반응에서의 위치정보는 방사선 선원의 영상을 재구성하는데 있어서 매우 중요한 기본정보이다. 이에 대부분의 위치 검출 기술을 이용하여 검출기안에서의 일어난 단일 반응의 위치정보를 알아낼 수 있다. 그러나 섬광체 안에서의 다중산란의 경우 각각의 산란위치를 개별적으로 측정할 수 없고 여러 산란위치의 평균만이 구해질 수 있어서 측정된 방사능의 위치정보에 불확실성이 존재하게 된다. 이 논문에서는 이러한 다중산란에 따른 위치 불확실성을 몬테카를로 시뮬레이션으로 계산하였다. 시뮬레이션 모델은 복합 집속 카메라에 사용된 $50{\times}50{\times}5mm\;LaCl_3$(Ce) 섬광체(pixel크기는 $2{\times}2{\times}5mm$)이다. 복합 집속 카메라는 광전효과와 컴프턴 산란 모두에서 정보를 얻으므로 방사선의 반응에서 부분에너지만 (검출기에) 검출되는 경우와 모든 에너지가 검출 되는 경우를 나누어 위치 불확실성을 계산하였다. 부분에너지만 검출되는 경우 (PED) 위치의 표준편차는 $1{\sim}2mm$ 미만으로 다중산란에 의한 불확실성이 크지 않다는 것을 알 수 있다. PED의 경우 다중산란의 영향이 크지 않으므로 이러한 다중산란은 컴프턴 카메라의 성능에 큰 영향을 미치지 않는다는 것을 알 수 있다. 그러나 모든 에너지가 검출되는 경우 (FED), 122keV입사방사선의 경우를 제외하면, 그 위치의 표준편차가 1차 검출기의 pixel크기에 2배에 달한다. 그러므로 복합 집속 카메라의 코드화된 마스크를 설계하는데 있어 재구성된 영상의 잡음을 방지하기 위해 다중산란에 의한 표준편차가 고려되어야 한다. 모든 입사 방사선에너지에 대하여 FED에 의한 위치 불확실성은 PED에 의한 것 보다 크며 PED 대 FED의 비는 입사방사선의 에너지가 증가함에 따라서 커진다. PED와 FED의 경우 모두 위치의 불확실성이 입사방사선의 에너지에 따라 달라졌다.

• Journal of Nutrition and Health
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• 제51권5호
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• pp.369-378
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• 2018

본 연구에서 고지방식이로 비만을 유도한 생쥐는 식이 4주 후 지방조직의 형태학적 변화가 관찰되었고 생식기 지방조직의 무게가 증가하였으며, 혈장 중성지방 및 혈당치도 현저하게 증가하였다. 고지방식이 6주 후 몸무게의 유의한 증가가 관찰되기 시작하였으며, 뒤다리넙적근과 어깨사이 지방조직의 무게는 감소하고, 생식기 지방조직 및 간의 무게는 증가하였다. 지방조직의 형태학적 변화가 시작되는 고지방식이 유도 4주 후 혈장 내 40종의 시토카인 및 케모카인의 변화를 동시에 관찰하여 대조군과 비교해 본 결과, CXCL12 (SDF-1)와 CXCL13 (BLC)의 발현이 가장 현저하게 증가하였으며, G-CSF의 발현도 다소 증가하였다. 혈장 내 염증성 시토카인의 발현은 전반적으로 낮았다. 이상의 결과를 종합하면 고지방식이 유도 비만 초기에 만성 염증 상태로 진입하기 전 혈장 내 CXCL12와 CXCL13의 발현이 현저히 증가하는 것을 밝혔으며, CXCL12와 CXCL13의 증가로 B 세포, T 세포 및 단핵구가 혈관을 빠져나가 지방조직 및 지방조직 주변 림프조직으로 이동하여 지방조직 재형성과 국소 지방조직 면역에 관여할 것으로 보인다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1202-1208
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• 2015

The effects of daily dietary Bacillus subtilis (Bs), and adding L-tryptophan, fructan, or casein to fecal fermentation broths were investigated as means to reduce the production of noxious gas during manure fermentation caused by ammonia, hydrogen sulfide ($H_2S$), and 3-methylindole (skatole). Eighty swine ($50.0{\pm}0.5kg$) were equally apportioned to an experimental group given Bs in daily feed, or a control group without Bs. After 6 weeks, fresh manure was collected from both groups for fermentation studies using a $3{\times}3$ orthogonal array, in which tryptophan, casein, and fructan were added at various concentrations. After fermentation, the ammonia, $H_2S$, L-tryptophan, skatole, and microflora were measured. In both groups, L-tryptophan was the principle additive increasing skatole production, with significant correlation (r = 0.9992). L-tryptophan had no effect on the production of ammonia, $H_2S$, or skatole in animals fed Bs. In both groups, fructan was the principle additive that reduced $H_2S$ production (r = 0.9981). Fructan and Bs significantly interacted in $H_2S$ production (p = 0.014). Casein was the principle additive affecting the concentration of ammonia, only in the control group. Casein and Bs significantly interacted in ammonia production (p = 0.039). The predominant bacteria were Bacillus spp. CWBI B1434 (26%) in the control group, and Streptococcus alactolyticus AF201899 (36%) in the experimental group. In summary, daily dietary Bs reduced ammonia production during fecal fermentation. Lessening L-tryptophan and increasing fructan in the fermentation broth reduced skatole and $H_2S$.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.