강유전체 캐패시터의 회로 시뮬레이션 모델과 이의AHDL 구현

김시호,Kim, Shi-Ho 대한전자공학회 2000 電子工學會論文誌-SD (Semiconductor and devices) Vol.37 No.10

본 연구에서는 강유전체의 이력 특성을 정밀하게 계산하기 위한 모델을 제공하였다. 본 모델은 2중 전위우물에 근거한 반경험적 분극 천이 모델에 기초하고 있으며 프라이사흐의 이력 함수의 분포 모델의 물리적 특성과도 잘 일치되고 있음을 보였다. 본 모델은 강유전체 이력 특성의 천이 경사도와 임프린트 특성을 고려하고 있으며 인가 전압의 극성이 바뀌는 경우에 발생되는 부 이력 경로에 대해서도 정확하게 분극 전하의 변화를 표현하고 있음을 보였다. 본 모델의 예측 결과는 PZT와 SBT의 두 종류의 강유전체에 대해서 측정 결과와 잘 일치하고 있음을 보였다. 또한, 본 모델을 AHDL 코드로 구현하여 스펙트레 시뮬레이터를 통하여 회로 설계를 할 수 있는 환경을 제공하였다. We provided a model for accurately computing the Hysteresis characteristics of the ferrelectric thin film capacitors. This model is developed form the semi-empirical ferroelectric model based on the double well harmonic oscillator. We have seen that this model is consistent with physical analysis using the Preisach's hysteresis distribution. This model includes the parameters representing the slope of changing Hysteresis curves and the imprint of ferroelectric capacitors. Besides, we showed that this model could predict accurate sub-hystersis loop by the turning points when the polarities of applied voltage were changed before saturation. The simulation and measurement result showed that this model is well applicable to both PZT and SBT materials. This model has been described by AHDL and successfully implemented into Spectre simulator to provide circuit design environment of commercial CAD tools such as Cadence software.

히트파이프를 이용한 하이브리드 차량의 배기열 회수 열전발전시스템

김선국(Kim Sun-Kook),원병철(Won Byeong Cheol),이석호(Rhi Seok-Ho),김시호(Kim Shi-Ho),유정호(Yoo Jeong-Ho) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5

박막형 열전 소자를 이용한 Chip-on-Board(COB) 냉각 장치의 설계

유정호(Jung-Ho Yoo),이현주(Hyun-Ju Lee),김남재(Nam-Jae Kim),김시호(Shi-Ho Kim) 대한전기학회 2010 전기학회논문지 Vol.59 No.9

A thin film thermoelectric cooler for COB direct assembly was proposed and the COB cooler structure was modeled by electrical equivalent circuit by using SPICE model of thermoelectric devices. The embedded cooler attached between the die chip and metal plate can offer the possibility of thin film active cooling for the COB direct assembly. We proposed a driving method of TEC by using pulse width modulation technique. The optimum power to the TEC is simulated by using a SPICE model of thermoelectric device and passive components representing thermal resistance and capacitance. The measured and simulated results offer the possibility of thin film active cooling for the COB direct assembly.

하이브리드 자동차의 배기열의 히트파이프 열전발전 기술

김선국 ( Sun Kook Kim ),이석호 ( Seok Ho Rhi ),김시호 ( Shi Ho Kim ) 충북대학교 산업과학기술연구소 2009 산업과학기술연구 논문집 Vol.23 No.2

Thermoelectric device is equipment that can produce electrical energy directly by a temperature difference. The purpose of this study is to recycle waste heat from vehicle exhaust gas by the thermoelectric elements(TE). The present experimental system used thermoelectric device with heat pipes as the heat spreading system. The goal of the heat pipe TE system was designed and manufactured to transfer heat uniformly and effectively. Heat to the installed TE modules were supplied from simulated exhaust pipe system with air burner. The present TE system can produce the electric power with single and multi layer modules. In case of multilayer modules, it was observed that each module can produce the 80% power output of a single module case. The experimental results for recycling waste heat through the present thermoelectric device indicate the simple novel concept to obtain the high efficiency power conversion.

전이학습을 통한 Fast Adaptive Meta Agent

이준용(Jun-Yong Lee),김시호(Shi-Ho Kim) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6

Reinforced-learning approaches have been proposed to cover many conditions of environment. As a result, many studies use meta-learner. Meta-learner had trained plenty of environment intended to generalizable to unseen environment. However, the generalizability on unseen environment could be broken when less relevant condition is given. In other word, the generalizability based on correlation between existing and unseen tasks. Therefore, there is no reliable factor to measure correlations of tasks. Our approach suggest Parameter reshape provide a good initial position. And we propose a measure of the distance between tasks at convergence speed.

MLC NAND 플래시 메모리의 셀 간 간섭현상 감소를 위한 등화기 알고리즘

김두환(Doo-Hwan Kim),이상진(Sang-Jin Lee),남기훈(Ki-Hun Nam),김시호(Shi-Ho Kim),조경록(Kyoung-Rok Cho) 대한전기학회 2010 전기학회논문지 Vol.59 No.6

This paper presents an equalizer reducing CCI(cell-to-cell interference) in MLC NAND flash memory. High growth of the flash memory market has been driven by two combined technological efforts that are an aggressive scaling technique which doubles the memory density every year and the introduction of MLC(multi level cell) technology. Therefore, the CCI is a critical factor which affects occurring data errors in cells. We introduced an equation of CCI model and designed an equalizer reducing CCI based on the proposed equation. In the model, we have been considered the floating gate capacitance coupling effect, the direct field effect, and programming methods of the MLC NAND flash memory. Also we design and verify the proposed equalizer using Matlab. As the simulation result, the error correction ratio of the equalizer shows about 20% under 20nm NAND process where the memory channel model has serious CCI.

하이브리드 자동차의 히트파이프 배기열 회수장치 개발

원병철(Byeong-Cheol Won),이석호(Seok-Ho Rhi),김선국(Sun-Kook Kim),이기우(Ki-Woo Lee),김시호(Shi-Ho Kim),유정호(Jeong-Ho Yoo) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

A new progressive advanced approach (Loop thermosyphon Thermoelectric Power generation System) is suggested to optimize heat recovery from vehicle exhaust gas. The present thermoelectric generators (TE) system offers the potential to increase vehicle fuel economy by converting a portion of engine waste heat to electricity. The feasibility of TE system is assessed in the context of hybrid electric vehicles. The present new TE system adopted heat pipes as a cooling heat exchanger of TE module. The present simulation study has been performed with CFD thermal modeling tool. In the present study, the proposed TE generation system for the future hybrid car could be recognized as the new waste heat recovery system. It was observed that the power output of the present TE generation system affected by various variables such as cooling media, thermal contact and supplied power etc. The present simulation results with the heat pipe TE module shows possibilities as an improved TE system for future thermoelectric hybrid vehicles.

발명의 특허 요건과 최근의 지재권 동향

김시호 圓光大學校 基礎自然科學硏究所 1997 基礎科學硏究誌 Vol.16 No.1

특허법에서 규정하고 있는 발명의 특허 등록의 요건을 살펴보고, 지적재산권 제도와 의의 및 체제를 알아보았다. 최근 선진국 및 우리나라의 지적재산권 관련 출원과 분쟁등 동향을 분석하였고, 이를 통하여 특허정보의 중요성을 인식하는데 주안점을 두었다. The legal requirement of patent registration in Korean Patent law and the new classified intellectual property rights are reviewed. The recent trend on applications for patent registration and legal conflicts of patent infrangement are analyzed in order to empersize the importance of patent information.

비휘발성 강유전체 메모리의 기준 셀 배치 및 선택 방법의 새로운 제안

김시호 圓光大學校 基礎自然科學硏究所 1999 基礎科學硏究誌 Vol.17 No.2

비휘발성 강유전체 메모리의 동작 수명을 향상시키기 위하여 선택 되지 않는 센스 앰프(S/A)에 연결되어 있는 기준셀은 읽기/쓰기 동작 시에 기준 셀의 워드 선을 선택하지 않음으로써 기준 셀에 인가되는 사이클의 획수를 줄이도록 메모리 배열을 구성하였다. 본 논문의 배열에서는 선택된 센스 앰프에 해당하는 기준 셀에 선택 신호가 기준 셀의 워드선과 AND 논리 게이트에 입력되어 해당 센스 앰프와 기준 셀의 워드 선이 모두 선택되었을 때에만 기준 셀의 MOS 트랜지스터가 켜지게 된다. 본 발명의 강유전체 메모리 배열에서는 선택된 센스 앰프에 연결된 해당 기준 셀의 선택 트랜지스터가 on되어 기준 셀의 정보가 읽어 지므로 기준 셀에 인가되는 전압의 사이클 횟수가 감소되므로 메모리의 전체수명이 증가하게 된다. We proposed a new reference cell array and a method for selecting these cells, in order to improve the read/write cycle time of 1T1C type ferroectric non volatile memory. The reference cell are truned on when both the column select signal and reference cell word line are enabled. The reference cell select signals can be generated from the column address decoder or from the additional circuits of address transition signal generator. We need more experiment of fabrication of proposed array and reliability test to exact characterization of proposed structure of array, we will do the experiment for futher works.

EPC class-1 generation-2 표준의 RFID 태그의 RF/아날로그 설계

조정현,김학수,김시호 충북대학교 컴퓨터정보통신 연구소 2006 컴퓨터정보통신연구 Vol.14 No.2

RFID는 사용되는 주파수에 따라 ID 확인과 실별, 물류, 전자지불, 출입통제, 교통카드 등에 사용되고 있다. 그중 UHF대역의 RFID 시스템은 유비쿼터스의 대표기술로 인식되고 있으며, 바코드를 대체하는 기술로 그 응용분야가 급속히 증가할 것으로 기대되고 있다. 본 논문은 EPCglobal Class-1 Generation-2 표준을 만족하는 UHF RFID 태그의 구성과 RF/아날로그 전단부 회로 설계를 설계하였다. 본회로는 매그너 칩의 0.25 CMOS 공정 파라미터를 사용하여 설계하였다. RFID systems can identify, trace and manage the objects equipped with a semiconductor tag chip. Tag chip stores and extracts the electronic code in the tag memory through RF signals. A typical RFID system consists of a reader and a number of tags. This paper describes the design of analog circuit of a RFID tag that is compatible with the EPCglobal Class-1 Generation-2 Protocol.