• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.61-64
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• 2000

본 논문에서는 cdma2000 규격을 채용한 역방향 링크 동기식 DS-CDMA 시스템을 시뮬레이션 하여 시스템의 성능을 분석하려다 cdma2000 시스템은 기존의 IS-95와는 달리 Pilot 채널을 이용하여 페이딩 채널을 추정하고 이를 이용하여 채널 환경에 의한 수신신호의 위상변화를 보상해 준다. 채널 추정필이 31pcg 심볼에서 Pilot 채널과 Traffic 채널의 최적의 전력비를 구하였다. 또한 시스템에 Power Control을 적용하여 Target FER을 만족시키기 위한 required Eb/No를 구하였고, 서로 다른 데이터율의 사용자가 동시에 전송할 때의 성능을 분석하였다.

• Journal of Intelligence and Information Systems
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• v.6 no.1
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• pp.1-16
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• 2000

This paper analyzes the approaches of Web-based expert systems by comparing their pros and cons. and proposes a methodology of implementing the Web-based backward inference engines with reduced burden to Web servers. There are several alternatives to implement expert systems under the WWW environment : CGI, Web servers embedding inference engines external viewers Java Applets and HTML. Each of the alternatives have advantages and disadvantages of each own in terms of development and deployment testing scalability portability maintenance and mass service. Especially inference engines implemented using HTML possess relatively large number of advantages compared with those implemented using other techniques. This paper explains the methodology to present rules and variables for backward inference by HTML and JavaScript and suggests a framework for design and development of HTML-based Expert System. A methodology to convert a traditional rule base to an Experts Diagram and then generate a new HTML-based Expert System from the Experts Diagram is also addressed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.793-798
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• 2016

In this work, the memory window characteristics of vertical nanowire device with asymmetric source and drain was analyzed using bipolar junction transistor mode for 1T-DRAM application. A gate-all-around (GAA) MOSFET with higher doping concentration in the drain region than in the source region was used. The shape of GAA MOSFET was a tapered vertical structure that the source area is larger than the drain area. From hysteresis curves using bipolar junction mode, the memory windows were 1.08V in the forward mode and 0.16V in the reverse mode, respectively. We observed that the latch-up point was larger in the forward mode than in the reverse mode by 0.34V. To confirm the measurement results, the device simulation has been performed and the simulation results were consistent in the measurement ones. We knew that the device structure with higher doping concentration in the drain region was desirable for the 1T-DRAM using bipolar junction mode.

• Journal of IKEEE
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• v.17 no.4
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• pp.428-433
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• 2013

In this study, an 4H-SiC Trench MOS Barrier Schottky (TMBS) rectifier which utilizes the trapezoid mesa structure and the upper half of the trench sidewall is proposed to improve the forward voltage drop and reverse blocking voltage concurrently. The proposed 4H-SiC TMBS rectifier reduces the forward voltage drop by 12% compared to the conventional 4H-SiC TMBS rectifier with the tilted sidewall and improves the reverse blocking voltage by 11% with adjusting the length of the upper sidewall. The Silvaco T-CAD was used to analyze the electrical characteristics.

• Journal of the Korean Society of Radiology
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• v.9 no.6
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• pp.343-348
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• 2015

The purpose of this study is a comparison of forward planning(FP) and inverse planning(IP) of a radiosurgery procedure. 10 patients of acoustic schwannoma MR image were used for treatment plan. FP-1,2 and IP were established under the same condition. FP and IP were compared by number of shot, conformity index(CI), paddic conformity index(PCI), gradiant index(GI) and treatment time. On average the treatment plan produced by IP tool provided an improved or similar CI, PCI, GI and reduced treatment time as compared to the FP (CI;FP-1:0.85, FP-2:0.86, IP:0.94, PCI;FP-1:0.79, FP-2:0.81, IP:0.78, GI;FP-1:2.94, FP-2:2.94, IP:3.01). The inverse planning system provides a clinically useful plan while reducing the planning time and treatment time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.197-201
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• 1975

다랭이 주낚의 양승방식에는 방향의 양승(On-tracing retrieve)방식과 역방향의 양승(Back-tracing retrieve) 방식의 두가지 방식이 있다. 순방향의 양승은 최초에 투승된 주낙끝에서부터 양승하기 시작하여 투승한 순과 같은 순으로 양승하는 것이고 역방향의 양승은 최후에 투승된 주낚끝에서부터 양승하기 시작하며 투승한 순과 반대순으로 양승하는 것이다. 주낚의 조업소요시간을 변갱하지 않고 양승방식만 변갱한다면 주낚의 평균침지시간은 변하지 않고 다만 침지시간의 분포구간만 변한다. 투승작업시간을 $\tau_1$, 투승작업이 끝나고 양승작업을 시작하기까지의 대기시간을 $\tau_2$, 양승작업시간을 $\tau_3$하면 주낚의 침지시간분포범위는 양승방식에 따라 다음과 같이 서로 다르다. $\tau_2$부터 $\tau_1+\tau_2+\tau_3$까지의 범위 역방향으로 양승할 때 $\tau_1+\tau_2$부터 $\tau_2+\tau_3$까지의 범위 임의시의 낚시 어획성능은 $F_0\varrho-^{-zt}$ ($F_0$는 초기어획성능, z는 감소계수, t는 투승후 경과시간)으로 나타낼 수 있고 침지시간 t인 낚시 Hro의 어획미수는 $H_{F_0}\frac{1-\varrho^{-zt}}{z}$로 나타낼 수 있으므로 주낙조업에서 낚시수 $H_G$개 이고 침지시간이 $\tau_\alpha$와 $\tau_\beta$ 범위내에서 분포하면 어획미수는 $C_G$는 다음과 같이 나타낼 수 있다. $$C_G=\frac{H_G}{\tau_\beta-\tau_\alpha}{\cdot}\frac{F_0}{Z}\int^{\tau_\beta}_{\tau_\alpha}(1-\varrho^{-zt})dt$$ $\tau_\alpha,\;\tau_\beta$의 값은 순방향의 양승에 있어서는 $\tau_\alpha=\tau_1+\tau_2,\;\tau_\beta=\tau_2+\tau_3$, 역방향은 양승에 있어서는 $\tau_\alpha=\tau_2,\;\tau_\beta=\tau_1+\tau_2+\tau_3$. 따라서 다랭이 주낚의 어획미수는 그 양승방식에 따라 차가 있고 순방향의 양승으로 더 많은 어획미수를 얻을 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.229-234
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• 1999

We analyzed the reliability characteristics in platinum schottky diodes with variations of n-type silicon substrates concentrations and temperature variations of measurements. The parameters of reliability measurement analysis are saturation current. turn-on voltage and ideality factor in the forward bias, the breakdown voltage in the reverse bias with device shapes. The shape of devices are square type and long rectangular type for edge effect. As a result, we analyzed that the forward turn-on voltage, barrier height, dynamic resistance and reverse breakdown voltage were decreased but ideality factor and saturation current were increased by increased concentration in platinum and n-silicon junction parts. In measurement temperature(RT, $50^{\circ}C$, $75^{\circ}C$), the extracted electrical parameter values of reliability characteristics were increased at the higher temperature under the forward and reverse bias. The long rectangular type devices were more decreased than the square type in reverse breakdown voltage by tunneling effects of edge part.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.345-352
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• 2002

In this paper, in order to evaluate the performance of IS-95 system reverse link in white gaussian noise and rayleigh fading environment, we suggest epochal proposal to improve computer run-time and its efficiency is verified in terms of the number of samples. MC(Monte Carlo) simulation is the most popular simulation technique lately, but MC simulation requires a number of samples at low bit error rate. Therefore, MC cannot avoid the limit of computer run-time. To alleviate these problems, we apply the suggested method called central moment technique to the reverse link of the IS-95 system and can obtain discrete probability mass functions from Nth order central moments of the less number of received signal samples than those required in MC. Continuous cumulative probability distribution function can be accurately estimated by using interpolation and the improvement effect for the number of samples is proven.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.41-44
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• 2004

양성자 주입 기술을 pn 다이오드의 동작 속도를 향상시키기 위한 방법 이용하였다. 양성자 주입은 에너지를 2.32 MeV, 2.55 MeV, 2.97 MeV로 변화시키며 수행하여, projection 범위를 각각 접합, 공핍, 중성영역에 위치하도록 하였다. 또한 각각의 에너지 조건에서 도즈를 $1{\times}10^{11}\;cm^{-2}\;1{\times}10^{12}\;cm^{-2},\;1{\times}10^{13}\;cm^{-2}$의 세가지 조건으로 변화시켰다. 양성자 주입 조건 변화에 따른 소자 동작특성의 변화를 관찰하기 위하여 소자의 전류-전압 특성, 용량-전압 특성, 역방향 회복시간 측정을 수행하였다. 분석결과 양성자를 주입하지 않은 소자에 비해 특성의 큰 열화없이 역방향 회복시간을 약 1/5 수준으로 단축시킬 수 있는 것으로 나타났다.

• Information and Communications Magazine
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• v.16 no.10
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• pp.112-124
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• 1999

본 논문에서는 FTTC/VDSL (Fiber-to-the-Curb/Very High-speed Digital Subscriber Line) 전송시스템의 개발동향과 ANSI, ETSI, ITU등의 표준화 위원회에서 현재 진행중인 VDSL 시스템의 표준화 작업에 대해 기술하였다. 특히, POTS (Plain Old Telephone Service), BA-ISDA(Basic Access Integrated Services Digital Network), HDSL(High-rate Digital Subscriber Line), SDSL (Single-pair HDSL), ADSL(Asymmetric Digital Subscriber Line) 등의 다양한 xDSL (Digital Subscriber Line) 서비스들에서 발생하는 NEXT (Near-end Crosstalk)/FEXT (Far-end Crosstalk)와 같은 crosstalk를 최소화하기 위해 제안된 VDSL시스템의 주파수 대역과 PSD (Power Spectral Density) mask에 관해 설명하고, 순방향(down-stream) 채널과 역방향(upstream) 채널의 데이터 전송률이 대칭적인 VDSL전송시스템과 비대칭적인 VDSL 전송시스템 간의 주파수대역의 호환성 문제, RFI(Radio Frequency Interference) ingress/egress 문제의 해결 방안에 관해 기술하였다. 또한, 현재 VDSL Coalition과 VDSL Alliance 간에 논의 중인 VDSL 전송시스템의 변복조 방식에 관한 표준화 작업과정 및 순방향과 역방향에 할당될 band 개수에 따른 시스템 성능의 장단점 등에 관해 살펴보았다. 끝으로 현재 국내에서 개발되고 있는 FTTC/VDSL 전송시스템의 전체구조를 요약하고, 네트워크에서 가입자쪽으로 순방향 데이터 전송에 사용된 51.84 Mb/s 19-CAP (Carrierless Amplitude/Phase Modulation) 전송시스템과 가입자 댁내에서 네트워크 방향으로 역방향 데이터 전송에 사용된 1.62 Mb/s QPSK (Quadrature Phase Shift Keying) burst-mode TDMA (Time Division Multiple Access) 전송시스템 등의 동작 원리 및 구조를 기술하였다.