• ETRI Journal
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• 제11권2호
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• pp.109-119
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• 1989

Based on the 2-dimensional charge-control simulation[4], a purely analytical model for MODFET's is proposed. In this model, proper treatment of the diffusion effect in the 2-DEG transport due to the gradual channel opening along the 2-DEG channel was made to explain the enhanced mobility and increased thershold voltage. The channel thickness and gate capacitance are experssed as functions of gate vlotage including subthreshold characteristics of the MODFET's analytically. By introducing the finite channel opening and an effective channel-length modulation, the slope of the saturation region of the I-V curves was modeled. The smooth transition of the I-V curves from linear-to-saturation region of the I-V curves was possible using the continuous Troffimenkoff-type of field-dependent mobility. Furthermore, a correction factor f was introduced to account for the finite transtition section forming between the GCA and the saturated section. This factor removes the large discrepanicies in the saturation region fo the I-V curves presicted by existing 1-dimensional models. The fitting parameters chosen in our model were found to be predictable and vary over relatively small range of values.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4595-4610
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• 2020

In the practical communication environment, the accurate channel state information (CSI) is difficult to obtain, which will cause the mismatch of resource and degrade the system performance. In this paper, to account for the channel uncertainties, a robust power allocation scheme for a downlink Non-orthogonal multiple access (NOMA) heterogeneous network (HetNet) is designed to maximize energy efficiency (EE), which can ensure the quality of service (QoS) of users. We conduct the robust optimization model based on worse-case method, in which the channel gains belong to certain ellipsoid sets. To solve the non-convex non-liner optimization, we transform the optimization problem via Dinkelbach method and sequential convex programming, and the power allocation of small cell users (SCUs) is achieved by Lagrange dual approach. Finally, we analysis the convergence performance of proposed scheme. The simulation results demonstrate that the proposed algorithm can improve total EE of SCUs, and has a fast convergence performance.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.303-308
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• 2003

In this paper, wave numerical modeling was experimented for the analysis of impact factors for the wave transmission as the incident wave and topographic conditions in the narrow channel sea. Recently, Although the results of many researcher for the wave modelling, numerical equations have limited to simulation of wave transformation effects. Despite of thispresent problems, the models was used to design the coastal structures in barrow channel sites. Finally, this paper estimated the wave model(mild slope eq. model) as the analysis of the wave energy transmission according to changing of impact factors(width of channel, bottom slope in channel, incident wave angle, wave period). As the results of numerical experiment, the major impact factors which influence to wave energy transmission were the width of channel and incident wave direction. But in the case that the width of channel is larger than 3L(L=Length of wave), the reduction of wave energy was small.

• 대한전자공학회논문지
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• 제22권6호
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• pp.58-62
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• 1985

이온 주입된 소형 MOSFET소자에 대한 해석적 문턱 전압 모델이 유도되었다. 일정한 도우핑 농도를 갖는 MOSFET에 적용되는 Yau 모델을 implanted channel구조와 bird's beat구조의 MOSFET에 대하여 적합한 형태로 수정하여 short channel 현상과 narrow width 현상을 정량적으로 설명하였다. Channel영역의 불순물 분포를 SUPREM 결과에서 2-step profile로 근사시켜 문턱 전압의 short channel model을 제안하였다. Weighting factor를 사용하여 bird's beat 영역의 불순물 분포를 고려함으로써 narrow width 현상을 성공적으로 설명하였다.

• Bulletin of the Korean Chemical Society
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• 제22권4호
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• pp.337-348
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• 2001

This article gives an overview of a recently developed channel system, frit-inlet asymmetrical flow field-flow fractionation (FI-AFlFFF), which can be applied for the separation of nanoparticles, proteins, and water soluble polymers. A conventiona l asymmetrical flow FFF channel has been modified into a frit-inlet asymmetrical type by introducing a small inlet frit near the injection point and the system operation of the FI-AFlFFF channel can be made with a great convenience. Since sample components injected into the FI-AFlFFF channel are hydrodynamically relaxed, sample injection and separation processes proceed without interruption of the migration flow. Therefore in FI-AFlFFF, there is no requirement for a valve operation to switch the direction of the migration flow that is normally achieved during the focusing/relaxation process in a conventional asymmetrical channel. In this report, principles of the hydrodynamic relaxation in FI-AFlFFF channel are described with equations to predict the retention time and to calculate the complicated flow variations in the developed channel. The retention and resolving power of FI-AFlFFF system are demonstrated with standard nanospheres and protreins. An attempt to elucidate the capability of FI-AFlFFF system for the separation and size characterization of nanoparticles is made with a fumed silica particle sample. In FI-AFlFFF, field programming can be easily applied to improve separation speed and resolution for a highly retaining component (very large MW) by using flow circulation method. Programmed FI-AFlFFF separations are demonstrated with polystyrene sulfonate standards and pululans and the dynamic separation range of molecular weight is successfully expanded.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2007년도 International Meeting of the Microbiological Society of Korea
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• pp.22-23
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• 2007

• 대한전자공학회논문지SD
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• 제49권4호
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• pp.1-6
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• 2012

본 논문에서는 고주파에서 동작하는 터널링 전계효과 트랜지스터 (TFET)의 소신호 파라미터 추출과 이에 대한 분석을 다루고 있다. 시뮬레이션으로 구현된 TFET의 채널 길이는 50 nm에서 100 nm 사이에서 변화되었다. Conventional planar MOSFET 기반의 quasi-static 모델을 이용하여 TFET의 파라미터 추출이 이루어졌으며 다른 채널 길이를 갖는 TFET에 대한 소신호 파라미터의 값을 게이트 바이어스 변화에 따라서 추출하였다. 추출 결과로부터 effective gate resistance와 transconductance, source-drain conductance, gate capacitance 등 주요 파라미터의 채널 길이 변화에 따른 경향성이 conventional MOSFET과 상당히 다른 것을 확인하였다. 그리고 $f_T$는 MOSFET과 달리 게이트 길이 역수의 값에 정확히 반비례하는 특성을 보였으며 TFET의 고주파 특성 향상을 transconductance의 개선이 아닌 gate capacitance의 감소에 의하여 가능함을 알 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권2호
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• pp.494-513
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• 2019

A multi-channel access problem based on hypergraph model in ultra-dense small cell networks is studied in this paper. Due to the hyper-dense deployment of samll cells and the low-powered equipment, cumulative interference becomes an important problem besides the direct interference. The traditional binary interference model cannot capture the complicated interference relationship. In order to overcome this shortcoming, we use the hypergraph model to describe the cumulative interference relation among small cells. We formulate the multi-channel access problem based on hypergraph as two local altruistic games. The first game aims at minimizing the protocol MAC layer interference, which requires less information exchange and can converge faster. The second game aims at minimizing the physical layer interference. It needs more information interaction and converges slower, obtaining better performance. The two modeled games are both proved to be exact potential games, which admit at least one pure Nash Equilibrium (NE). To provide information exchange and reduce convergecne time, a cloud-based centralized-distributed algorithm is designed. Simulation results show that the proposed hypergraph models are both superior to the existing binary models and show the pros and cons of the two methods in different aspects.

• 대한한의학방제학회지
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• 제27권4호
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• pp.237-244
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• 2019

Objectives : The purpose of this study was to investigate the effects of Carthami flos on pacemaker potentials of small intestinal and colonic Interstitial Cells of Cajal (ICC). Methods : To dissociate the ICC, we used enzymatic digestions from the small intestine and colon in mice. In the ICC, the electrophysiological whole-cell patch-clamp configuration was used to record pacemaker potentials in the cultured ICC. Results : 1. The ICC generated pacemaker potentials in the murine small intestine and colon. 2. Pretreatment with a Ca²⁺ free solution and thapsigargin, a Ca²⁺-ATPase inhibitor in the endoplasmic reticulum, stopped the pacemaker potentials. In the case of Ca²⁺-free solutions, Carthami flos did not induce membrane depolarizations in the murine small intestine and colon. However, when thapsigargin in a bath solution was applied, Carthami flos induced membrane depolarizations only in the murine colon. 3. Pretreatment with 2-APB (transient receptor potential melastatin (TRPM) channel inhibitor) abolished the pacemaker potentials and suppressed Carthami flos-induced effects in the murine small intestine and colon. 4. However, pretreatment with T16Ainh-AO1 (Ca²⁺ activated Cl- channel; anoctamin 1 (ANO1) inhibitor) did not affect the pacemaker potentials and induced Carthami flos-induced effects only in the murine small intestine. Conclusions : These results suggest that Carthami flos can modulate the pacemaker activity of ICC and the mechanisms underlying pacemaking in ICC might be different in the small intestine and the colon.

• 한국수자원학회논문집
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• 제37권8호
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• pp.623-630
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• 2004

본 논문에서는 수리모형 실험을 통하여 지류와 본류의 합류점의 접근각도, 본류의 유량 및 본류와 지류의 유량비 변화에 따른 합류부의 수리학적 특성을 파악하였다. 실험은 수로길이 450cm의 수로에서 실시하였으며, 본류와 지류의 수로폭은 각각 40cm와 32cm이었으며, 4조의 물탱크와 펌프가 설치되었다. 합류점 부근의 정체 구간의 길이는 접근각도가 증가함에 따라 증가되며, 본류의 유량과 지류와 본류와의 유량비가 증가되는 경우에도 이 경향은 동일하다. 그러나 동일한 합류점 접근각도와 유량비에 있어서 본류 유량 변화에 따른 합류점 부근의 정체구간 변화는 매우 적게 나타나고 있다. 또한 본류와 지류의 유량비가 증가할수록 유속의 정체 구간의 길이가 커져, 유사의 퇴적증가를 유도하는 주요원인이 된다. 합류점 부근의 가속유로는 접근각도가 작을수록 수로 내 중앙부에 한정되지만, 접근각도가 증가할수록 영향권이 증가된다.