• Title/Summary/Keyword: Saturation Length

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A Study on the Characteristic Analysis of NUDFET by FEM (FEM에 의한 NUDFET의 특성해석에 관한 연구)

  • Kim, Jong-Ryeul;Jung, Jong-Chuck;Kim, Young-Cig;Sung, Man-Young;Cho, Ho-Yeol
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1247-1249
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    • 1993
  • In this paper, NUDFET(NonUniformly Doped Field Effect Transistor) is presented as an alternative which offers the possibility of reducing the power necessary to operate switching circuits without a substantial loss in speed. The purpose of this NUDFET is to modify the electric field profile in order to cause carrier velocity saturation to occur at a lower voltage than it would occur in the uniformly doped device of the same channel length. The more MESFET and NUDFET circuits are realized, the more accurate model ins the performance of these devices become required. Analytic model ins was replaced by numerical analysis because of the complexity of device configuration. In this paper, FEM is selected because of simpler local mesh refinement and smaller computer memory than FDM. For accurate analysis, this paper has applied the Scharfetter-Gummel(S-G) Scheme and seven-point Gaussian Quadrature rule to assembly of the finite-element stiffness matrices and right-hand side vector of the semiconductor equations.

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Determination of Optimal Traffic Signal Cycle using Neural Network (신경망을 이용한 최적 교통신호주기 결정)

  • 홍유식;박종국
    • Journal of the Korean Institute of Intelligent Systems
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    • v.6 no.3
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    • pp.51-62
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    • 1996
  • Electro sensitive traffic system can not consider passenger car unit, so it causes start up delay time and passenger waiting time. In this paper, it antecedently creates passenger car unit at the bottom intersection using neural network. But, sometimes it can make mistakes due to changes in car weight, car speed, and passing area. Therefore, it consequently reduces the car waiting time and start-up delay time using fuzzy control of feed-back data. Moreover, to prevent spillback, it can adapt control even though upper traffic intersection has a different saturation rate, road length, road slope and road width.

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Access delay and packet delay of EDCA in IEEE 802.11e wireless network (IEEE 802.11e EDCA 무선랜의 매체 접속 지연 시간 및 정상 상태에서의 패킷 지연 분석)

  • Lee, Yu-Tae;Jang, Jong-Min;Lee, Key-Sang;Kim, Dong-Il;Kim, Chang-Kyu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.8
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    • pp.1420-1426
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    • 2008
  • This paper derives medium access delay of each AC(Access Category) in a stationary station using inter-departure time of IEEE 802.11e WLAN(Wireless LAN). Inter-departure time of IEEE 802.11e WLAN is obtained using saturation throughput of IEEE 802.11e WLAN which was the topic of our prior work. By using a simple queueing model, we evaluate mean queue length and mean delay for each AC on stationary condition. We calculate performance of each AC using this simple model and validate results using simulation.

Weather-insensitive Optical Free-space Communication Using the Gain-Saturated Optical Fiber Amplifier (이득 포화된 광섬유증폭기를 사용하는 기상에 둔감한 무선광통신)

  • Shin, Kyung-Woon;Hurh, Yoon-Suk;Lee, Sang-Hoon;Lee, Jae-Seung
    • Korean Journal of Optics and Photonics
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    • v.17 no.5
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    • pp.396-400
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    • 2006
  • We present a weather-insensitive optical free-space communication method supporting optical packet channels. It operates optical fiber amplifiers in gain-saturation regions. When the propagation loss gets too high, it decreases the average packet rate, or the average packet length, or both, to increase the optical power level launched into the free-space. As a demonstration, we transmit $8{\times}10$ Gigabit Ethernet channels over a terrestrial distance of 2.4 km. One gain-saturated free-space optical repeater is used at the halfway point.

Evaluation of the Humpty Dumpty Falls Scale: An Analysis of Electronic Medical Records (소아 낙상위험 측정도구 (Humpty Dumpty Falls Scale) 평가: 전자의무기록을 이용하여)

  • Cho, Yun Hee;Kim, Young Ju
    • Journal of Korean Clinical Nursing Research
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    • v.25 no.2
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    • pp.142-150
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    • 2019
  • Purpose: The aim of this study was to evaluate the efficiency of the Humpty Dumpty Falls Scale as one of the falls risk assessment tools, and also to evaluate risk factors as predictors of falls in pediatric patient populations. Methods: In a retrospective, case-control design with data from the electronic medical records of 13 pediatric patients who fell and 1,941 who did not fall before matching and 429 who did not fall after matching by gender, age, diagnosis, and length of stay. Results: All the variables showed no significant differences after matching. At the cutoff score of 13, sensitivity, specificity, negative and positive predictive values were 92.3%, 37.1%, 99.9%, and 0.01%, respectively. The area under the Receiver Operating Characteristics was 0.597. The results from the logistic regression showed that the pediatric inpatient population who had higher risk scores was significantly associated with falls. The odds ratios ranged from 1.31 to 4.71 with 90% confidence interval. Conclusion: The saturation impairments criterion as one of the diagnostic parameter was negatively associated with falls, but the relative risk score was higher than the other criteria. Therefore, it seems that the diagnostic parameter seems to be required to verify results through large sample studies.

Technical Trends in Next-Generation GaN RF Power Devices and Integrated Circuits (차세대 GaN RF 전력증폭 소자 및 집적회로 기술 동향)

  • Lee, S.H.;Lim, J.W.;Kang, D.M.;Baek, Y.S.
    • Electronics and Telecommunications Trends
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    • v.34 no.5
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    • pp.71-80
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    • 2019
  • Gallium nitride (GaN) can be used in high-voltage, high-power-density/-power, and high-speed devices owing to its characteristics of wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. In this study, we investigate the technology trends for X-/Ku-band GaN RF power devices and MMIC power amplifiers, focusing on gate-length scaling, channel structure, and power density for GaN RF power devices and output power level and output power density for GaN MMIC power amplifiers. Additionally, we review the technology trends in gallium arsenide (GaAs) RF power devices and MMIC power amplifiers and analyze the technology trends in RF power devices and MMIC power amplifiers based on both GaAs and GaN. Furthermore, we discuss the current direction of national research by examining the national and international technology trends with respect to X-/Ku-band power devices and MMIC power amplifiers.

Foliar Characteristics and Photosynthetic Efficiency of Three Species of Schisandraceae Trees Distributed in Korea (우리나라에 분포하는 오미자과 2속 3종의 잎 형질 및 광합성 특성)

  • Kim Pan-Gi;Lee Kab-Yeon;Kim Sea-Hyun;Han Sang-Sup
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.1 no.2
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    • pp.90-96
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    • 1999
  • Foliar and physiological characteristics of Schisandraceae plants distributed in Korea were investigated to elucidate differences in growth and the variations of inter and intra species of the plants. For this study, three species of Schisandraceae plants were used; i) Schisandra chinensis, decidious broad-leaved tree, ii) S. nigra, decidious broad-leaved tree, including monoecious, male and female types, ii) Kadsura japonica, evergreen broad-leaved tree. There were no significant differences in leaf length and width among three species, but leaves of Schisandra sp. plants were shorter and wider relative to those of K. japonica. The length of petiole of Schisandra sp. plants was greater than that of K. japonica and the difference was evident between female type of S. chinensis and K. japonica as longer as two times. Schisandra sp. trees showed larger size of stomata, but fewer numbers of stomata, compared with K. japonica. Although substantial changes in leaf morphology were not found in the Schisandraceae plants grown in different environmental conditions, the foliar length of K. japonica was seemed to be increased with increasing an altitude. Chlorophyll contents were also variable in inter and intra species and in, general K. japonica showed higher levels of chlorophyll contents relative to Schisandra sp. plants. K. japonica also showed higher light compensation point(LCP), light saturation point(LSP) and $CO_2$ assimilation rates at LSP, compared with Schisandra sp. trees. However, Schisandra sp. trees showed lower respiration per photosynthesis rates at LSP. The finding suggested that Schisandra sp. trees were acclimated to the growth conditions of lower light intensity with more effective photosynthetic activity. This was also confirmed by the fact that Schisandra sp. plants grown in shading places of a forest demonstrated the elevated rates of net $CO_2$ assimilation under the conditions of low light intensity.

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The optimum media size and composition for sawdust culture of Lentinula edodes (Strain: JNM3022) (표고버섯(JNM3022) 톱밥재배에 적합한 배지조성과 배지크기)

  • Choi, Duck Soo;Jung, Kyung Ju
    • Journal of Mushroom
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    • v.6 no.3_4
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    • pp.131-137
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    • 2008
  • These experiments were conducted to search for the optimum media size and composition for culture of Lentinula edodes (JNM3022). Considering the incubation period and the successful culturing rate, the optimum media size was length 25 $cm{\times}diameter$ 14 cm (weight 2.5 kg). The saturation moisture amount of Oak sawdust was 251 ml/100 g. It is a half of pine sawdust 495 ml/100 g. Considering the hypha growing speed and hypha density, the optimum media composition was Oak sawdust 80%+ wheat bran 20% and Oak sawdust 80%+ rice bran 20% In 10 treatments of media composition. The optimum moisture amount of media for growing Lentinula edodes (JNM3022) was 55%. Injection pipe with 20 holes in media was reduced the incubation periods to 11 days when 20cm length media and 32 days when 30cm length media compare to control. The best method for browning media surface was change temperature condition above $10^{\circ}C$ and punching the vinyl bag. This treat could shortened the browning periods to 54 days.

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Identification of Introduced Gene and Its Expression and Gene Stability Assessment for Event Selection of Genetically Modified Plant toward Approval: Cucumber Mosaic Virus Resistant Hot Pepper (상업용 유전자 변형작물 이벤트 선발을 위한 도입유전자 확인, 발현 및 세대간 안정성 평가 : 오이모자이크바이러스 저항성 GM 고추)

  • Kang, Seung-Won;Han, Bal-Kum;Lee, Tae-Ho;Kim, Eun-Ji;Lee, Gung-Pyo
    • Horticultural Science & Technology
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    • v.30 no.2
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    • pp.192-200
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    • 2012
  • For the development of genetically modified plants, it is important to verify various factors which potentially affect the risk assessment as well as to establish an experimental program to produce scientific and reliable data. However, it is a time and cost consuming process to develop GM plants as well as to prepare scientific and convincible data for government's approval. Therefore, using the transgenic hot pepper tolerant to a new CMV pathotype, we attempted to suggest few methodological procedures, such as probe saturation for southern blot analysis and RT-PCR and ELISA for expression analysis, for identification and stability evaluation of inserted gene in genetically modified plant which are required for submission for approval. Ten partially overlapped probes covering full length of inserted gene were produced. We could identify that the inserted gene was stacked as a single copy as well as no partial element existed. Also, we could identify the stability of the inserted gene stacked in hot pepper using probe saturation. In the expression analysis with RT-PCR and ELISA, we also could provide the stable expression of transcript and proteins in leaves and placenta and pericarp of fruits of the CMV-resistant hot pepper.

Removal of NAPL from Aquifer Using Surfactant-enhanced Air Sparging at Elevated Temperature (승온조건의 SEAS(surfactant-enhanced air sparging) 기술을 이용한 대수층 NAPL(n-decane)의 휘발제거)

  • Song, Young-Su;Kwon, Han-Joon;Kim, Heon-Ki
    • Journal of Soil and Groundwater Environment
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    • v.14 no.6
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    • pp.87-94
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    • 2009
  • Surfactant-enhanced air sparging (SEAS) was developed to suppress the surface tension of groundwater prior to air sparging resulting in higher air saturation and larger contact area between NAPL and gas during air sparging. Larger contacting interface between NAPL and gas means faster mass transfer of contaminants from NAPL to gas phase. This new technique, however, is limited to relatively volatile contaminants because vaporization is its basic mechanism of mass transfer. In this study, SEAS was tested at an elevated temperature for a semi-volatile n-decane, which is expected not to be a good candidate of SEAS application due to its low vapor pressure at ambient temperature. Three sparging experiments were conducted using 1-dimensional column (5 cm id, 80 cm length) packed with sand; (1) ambient temperature ($23^{\circ}C$), column saturated with distilled water, (2) SEAS at ambient temperature ($23^{\circ}C$), for n-decane contaminated sand, (3) SEAS at elevated temperature ($73^{\circ}C$), for n-decane contaminated sand. Higher air saturation was achieved by SEAS compared to that by air sparging without surfactant application. The n-decane removal efficiency of SEAS at elevated temperature was significantly higher(> 10 times) than that of ambient SEAS. The n-decane concentrations in the gas effluent from column during SEAS at $73^{\circ}C$ are found to be 10 times of those measured at ambient temperature. Thus, SEAS technique can be applied for removal of semi-volatile contaminants provided that an appropriate technique for elevating aquifer temperature is available.