• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.286-291
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• 2015

For highly scalable NAND flash memory applications, a compact ($4F^2/cell$) nonvolatile memory architecture is proposed and investigated via three-dimensional device simulations. The back-channel program/erase is conducted independently from the front-channel read operation as information is stored in the form of charge at the backside of the channel, and hence, read disturbance is avoided. The memory cell structure is essentially equivalent to that of the fully-depleted transistor, which allows a high cell read current and a steep subthreshold slope, to enable lower voltage operation in comparison with conventional NAND flash devices. To minimize memory cell disturbance during programming, a charge depletion method using appropriate biasing of a buried back-gate line that runs parallel to the bit line is introduced. This design is a new candidate for scaling NAND flash memory to sub-20 nm lateral dimensions.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.957-960
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• 2003

Many solar cell way need to be connected by series or parallel to extract the high power Especially, during parallel operation to reduce circulation current the individual converter has to share and control the load current. Generally, Current Sharing(CS) can be implemented using droop and active current sharing method. In this paper, one 3[KW] PWM converter was replaced as one 3[KW] solar cell array(3 parallels, each parallel has twenty single modules), two 3[KW] solar cell way Is Paralleled to generate 6[KW] power. Also each converter used voltage-current controller and Automatic MSCPM(Master-Slave Current-programming Method) for current sharing(AS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.33-36
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• 1994

The characteristics of the nonvolatile MONOS memory devices as the nitride thickness is scaled down while maintaining constant tunneling oxide thickness and blocking oxide thickness have been investigated in order to obtain the 5V-programmable E$^2$PROM. We have found that 1V memory window for a 5V programming voltage and 10 year data retention can be achieved in the scaled MONOS memory devices with a 50 blocking oxide, a 57 nitride and a 19 tunneling oxide.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.2
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• pp.70-78
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• 2005

In this paper, a novel rotor flux estimation method of an induction motor using support vector regression(SVR) is presented. Two well-known different flux models with respect to voltage and current are necessary to estimate the rotor flux of an induction motor. Training of SVR which the theory of the SVR algorithm leads to a quadratic programming(QP) problem. The proposed SVR rotor flux estimator guarantees the improvement of performance in the transient and steady state in spite of parameter variation circumstance. The validity and the usefulness of proposed algorithm are throughly verified through numerical simulation.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.136-136
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• 2011

반도체 및 전자기기 산업에 있어서 NVM은 아주 중요한 부분을 차지하고 있다. NVM은 디스플레이 분야에 많은 기여를 하고 있는데, 측히 AMOLED에 적용이 가능하여 온도에 따라 변하는 구동 전류, 휘도, color balance에 따른 문제를 해결하는데 큰 역할을 한다. 본 연구에서는 bottom gate 구조의 nc-Si NVM 실험을 진행하였다. P-type silicon substrate (0.01~0.02 ${\Omega}-cm$) 위에 Blocking layer 층인 SiO2 (SiH4:N2O=6:30)를 12.5nm증착하였고, Charge trap layer 층인 SiNx (SiH4:NH3=6:4)를 20 nm 증착하였다. 마지막으로 Tunneling layer 층인 SiOxNy은 N2O (2.5 sccm) 플라즈마 처리를 통해 2.5 nm 증착하였다. 이러한 ONO 구조층 위에 nc-Si을 50 nm 증착후에 Source와 Drain 층을 Al 120 nm로 evaporator 이용하여 증착하였다. 제작한 샘플을 전기적 특성인 Threshold voltage, Subthreshold swing, Field effect mobility, ON/OFF current ratio, Programming & Erasing 특성, Charge retention 특성 등을 알아보았다.

• 전기의세계
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• v.24 no.5
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• pp.107-110
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• 1975

This paper describes computational algorithms and a computer program for optimum determinations of wire conductor sizes of radial or tree-type distibution lones with given constraints. Here, The objective function is defined as the total summation of the volume or weight of respective conductor materials required for buildingup the entire distributing system. Four categories of constraints are applied to the obiective function. That is, on the respective load points constraint is imposed by a specified voltage drop limit, and the respective line elements are capable of carrying the current safely(safety current) and also must maintain the minimum thickness in viewpoint of mechanical strength and legal requirements. And finally, the conductor sizes have to be selected among the standardized size levels of the products. These kinds of optimization problems cannot be solved by the ordinary optimization tediniques such as the Linear Programming Method, SUMT Technique, etc. This paper, therefore, successfully devised the powerful alorithms to solve the problem, using the particular properties or characteristics ingerent to the radial or tree-type distribution system. The computer program developed from the algorithms was applied to several sample systems and shown to be exact and very efficient.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.672-681
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• 2012

A potential breakthrough of the electrification of the vehicle fleet will incur a steep rise in the load on the electrical power grid. To avoid huge grid investments, coordinated charging of those vehicles is a must. In this paper, we assess algorithms to schedule charging of plug-in (hybrid) electric vehicles as to minimize the additional peak load they might cause. We first introduce two approaches, one based on a classical optimization approach using quadratic programming, and a second one, market based coordination, which is a multi-agent system that uses bidding on a virtual market to reach an equilibrium price that matches demand and supply. We benchmark these two methods against each other, as well as to a baseline scenario of uncontrolled charging. Our simulation results covering a residential area with 63 households show that controlled charging reduces peak load, load variability, and deviations from the nominal grid voltage.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.396-398
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• 2003

This paper presents the scheme for load model based dispersed generation system (DGs) installation and operation in unbalanced distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The main idea of solving fuzzy nonlinear goal programming is to transform the original objective function and constraints into the equivalent multiple objective functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithms. The method proposed was applied to IEEE 13 bus test systems to demonstrate its effectiveness.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.1
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• pp.48-56
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• 2012

This paper deals with power electronic converter education program using LabVIEW. LabVIEW is a graphic based programming language with easy debugging, which is suitable for education program that can be used to study and figure out the operation of power electronic converters. When LabVIEW is employed as a simulation program of the operation of power electronic converters, the resulting program has the advantage such that the effects of the change of control variables and circuit parameters on the various variables such as the output voltage and the inductor current etc can be directly displayed without any separate compiling procedure. This paper shows the design procedure and the characteristics of the power electronics education program implemented by LabVIEW focusing on DC-DC converter among power electronic converters.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.3
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• pp.118-126
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• 2002

AVR parameter tuning for voltage control of generators has generally been done with the off-line open-circuit model of the synchronous generator. When the generator is connected on-line and operating with load the AVR operates in an entirely different environment from the open-circuit conditions. This paper describes a new method for AVR parameter tuning for on line conditions using SQP(Sequential Quadratic Programming) meshed with frequency response characteristics of linearized on-line system model. As the proposed method uses the un - line system model the tuned parameter sets show more optimal behavior in the on-line operating conditions. furthermore, as this method considers the performance indices that are needed for stable operation as constraints, AVR parameter sets that are tuned by this method could guarantee the stable performance, too.