• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.799-805
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• 2004

Two dimensional MEDICI simulator is used to study the characteristics of latch-up current of Dual Gate Emitter Switched Thyristor. The simulation is done in terms of the current-voltage characteristics, latch-up current density, ON-voltage drop and electrical property with the variations of p-base impurity concentrations. Compared with the other power devices such as MOS Controlled Cascade Thyristor(MCCT), Conventional Emitter Switched Thyristor(C-EST) and Dual Channel Emitter Switched Thyristor(DC-EST), Dual Gate Emitter Switched Thyristor(DG-EST) shows to have the better electrical characteristics, which is the high latch-up current density and low forward voltage-drop. The proposed DG-EST which has a non-planer p-base structure under the floating $N^+$ emitter indicates to have the better characteristics of latch-up current and breakover voltage.

• Smart Structures and Systems
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• 제14권4호
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• pp.643-658
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• 2014

This paper presents the design, modelling and, simulation and experimental results of a shape memory alloy (SMA) actuator based critical motion control application. Dynamic performance of SMA and its ability in replacing servo motor is studied for which the famous open loop unstable balancing ball and beam system direct driven by antagonistic SMA is designed and developed. Simulation uses the mathematical model of ball and beam structure derived from the first principles and model estimated for the SMA actuator by system identification. A PID based cascade control system consisting of two loops is designed and control of ball trajectory for various target positions with settling time as control parameter is verified experimentally. The results demonstrate the performance of SMA for a complicated i.e., under actuated, highly nonlinear unstable system, and thereby it's dynamic behaviour. Control strategies bring out the effectiveness of the actuator and its possible application to much more complex applications such as in aerospace control and robotics.

• 천문학회지
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• 제34권4호
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• pp.275-279
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• 2001

The study of incompressible magnetohydrodynamic (MHD) turbulence gives useful insights on many astrophysical problems. We describe a pseudo-spectral MHD code suitable for the study of incompressible turbulence. We review our recent' works on direct three-dimensional numerical simulations for MHD turbulence in a periodic box. In those works, we use a pseudo-spectral code to solve the incompressible MHD equations. We first discuss the structure and properties of turbulence as functions of scale. The results are consistent with the scaling law recently proposed by Goldreich & Sridhar. The scaling law is based on the concept of scale-dependent isotropy: smaller eddies are more elongated than larger ones along magnetic field lines. This scaling law substantially changes our views on MHD turbulence. For example, as noted by Lazarian & Vishniac, the scaling law can provide a fast reconnection rate. We further discuss how the study of incompressible MHD turbulence can help us to understand physical processes in interstellar medium (ISM) by considering imbalanced cascade and viscous damped turbulence.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1998년도 The 12th Symposium on Plant Biotechnology Vol.12
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• pp.83-96
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• 1998

The plant pigment proteins phytochromes are a molecular light sensor or switch for photomorphogenesis involving a variety of growth and developmental responses of plants to red and far-red wavelength light. Underscoring the photomorphogenesis mediated by phytochromes is the light signal transduction at molecular and cellular levels. For example, a number of genes activated by the phytochrome-mediated signal transduction cascade have been identified and characterized, especially in Arabidopsis thaliana. The light sensor/switch function of phytochromes are based on photochromism of the covalently linked tetrapyrrole chromophore between the two photoreversible forms, Pr and Pfr. The photochromism of phytochromes involves photoisomerization of the tetrapyrrole chromophore. The "photosensor" Pr-form ("switch off" conformation) of phytochromes strongly absorbs 660 nm red light, whereas the "switch on" Pfr-conformation preferentially absorbs 730 nm far-red light. The latter is generally considered to be responsible for eliciting transduction cascades of the red light signal for various responses of plants to red light including positive or negative expression of light-responsive genes in plant nuclei and chloroplasts. In this paper, we discuss the structure-function of phytochromes in plant growth and development, with a few examples of biotechnological implications.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권3호
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• pp.354-359
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• 2012

A transformerless converter suitable for multiphase drive application is presented in this paper. The topology employs a cascaded H-bridge rectifier as the interface between the grid and multi inverters which drive the multiphase motor. Compared with the conventional structure, the new topology eliminates the input transformer and also has the advantages such as four quadrant operation, simple configuration, low cost, high efficiency, and so on. The control strategies for the grid-side cascade H-bridge rectifier and the motor-side inverter are studied accordingly. Based on the multi-rotational reference frame, modular control scheme is developed to regulate the multiphase drive system. Simulation results show the proper operation of the proposed topology and the corresponding control strategy.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.339-340
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• 2007

Face detection plays an important role in HCI and face recognition. In this paper, we propose a rotation-invariant real-time face detection algorithm for color images in complex background. It consists of four processing step: (1) motion detection, (2) skin color region filler, (3) Eyemap detector for rotated face, and (4) Adaboost face classifier. This system has been tested in in-door environments, such as office and achieves over 95% detection rate.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.116-119
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• 1999

This paper presents a feeder waveguide array of slot array antennas for Direct Broadcasting from Satellite(DBS). The feed structure consists of a single waveguide placed on the same layer as radiating waveguide and is characterized by the unit divider, called a $\pi$-Junction. This K-function with an inductive wall splits part of the power into two branch waveguide through one coupling window, and can excite densely arrayed waveguide at equal phase and amplitude. The power dividing characteristics of a cascade of $\pi$ -functions are analyzed by Galerkin's method of moments. From the optimum simulation results based on the feeder waveguide using $\pi$ -Junction at 3.95GHz, we obtained the scattering matrices of the feeder divided power at 11.85CHz.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.404-407
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• 2003

Monolayers of lipids on a water surface have attracted much interest as models of biological membranes, but also as precursors of multilayer systems promising many technical applications. Until now, many methodologies have been developed in order to gain a better understand. Photoisomerization in monolayers of a novel azobenzene compound, azobenzene dendrimer, was investigated for the first time by means of the absorption spectrum and Maxwell displacement current (MDC) technique. Dendrimers are well-defined macromolecules exhibiting a tree-like structure, first derived by the cascade molecule approach. According to the absorption spectrum, trans-to-cis conversion ratio was estimated to the third generation of azobenzene dendrimer deposited onto a glass substrate. Temperature-dependent induced charge with trans-cis isomerization was also measured by means of MDC technique.

• Journal of Information Processing Systems
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• 제17권2호
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• pp.385-398
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• 2021

The complexity of deep learning models affects the real-time performance of gesture recognition, thereby limiting the application of gesture recognition algorithms in actual scenarios. Hence, a residual learning neural network based on a deep convolutional neural network is proposed. First, small convolution kernels are used to extract the local details of gesture images. Subsequently, a shallow residual structure is built to share weights, thereby avoiding gradient disappearance or gradient explosion as the network layer deepens; consequently, the difficulty of model optimisation is simplified. Additional convolutional neural networks are used to accelerate the refinement of deep abstract features based on the spatial importance of the gesture feature distribution. Finally, a fully connected cascade softmax classifier is used to complete the gesture recognition. Compared with the dense connection multiplexing feature information network, the proposed algorithm is optimised in feature multiplexing to avoid performance fluctuations caused by feature redundancy. Experimental results from the ISOGD gesture dataset and Gesture dataset prove that the proposed algorithm affords a fast convergence speed and high accuracy.

• Journal of Radiation Protection and Research
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• 제18권1호
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• pp.53-61
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• 1993

홀수 핵종인 $^{75}As$의 핵 구조를 분광학적 방법으로 연구하기 위하여 $^{75}Se$의 전자 포획에 의하여 방출되는 감마선에 대해 단일 감마선 측정과 감마-감마 동시측정 실험을 하였다. 본 실험에서 구한 각 상관관계 계수는 $A_{22}=-0.452{\pm}0.017,\;A_{44}=0$이고 279.5keV 전이 감마선에 대한 혼합비는 ${\delta}=-0.586{\pm}0.017$을 얻었다. 또한 낮은 준위에서의 에너지의 상대 강도를 정확히 측정한 후 이를 이용하여 환산 행렬 요소들을 계산한 후 단일 입자 모형의 관점에서 hindrance factor를 구했다. 그 결과 279.5 keV 감마 전이의 다중극도는 74.44%의 Ml 전이와 25.56%의 E2 전이를 포함한 혼합 전이이며 5/2 준위의 밴드구조를 $f_{5/2}$ proton준위에 바탕을 둔 1/2 [310]으로 결정하였다.