• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.287-290
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• 2004

A structure using the two-way shape memory effect (TWSME) returns to its initial shape by increasing or decreasing temperature under initial residual stress. Through the thermo-mechanical constitutive equation of shape memory alloy(SMA) proposed by Lagoudas et al., we simulate the behavior of a double actuator in which two SMA wires are attached to the tip of panel under the initially given residual stress. Through the numerical results conducted in the present study, the proposed actuator device is suitable for repeated actuation. The simulation algorithm proposed in the present study can be applied extensively to the analysis of the assembled .system of SMA-actuator and host structure in the practical applications.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.155-163
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• 1996

This paper presents vibration and position tracking control of a smart structure using shape memory alloy(SMA) actuators. A governing equation of motion of the proposed structure is obtained via Hamilton's princeple. The dynamic characteristics of the SMA actuator are experimentally identified and incorporated with the governing equation to furnish a control system model. Subsequently, a sliding mode controller which has inherent robustness to external disturbances is formulated on the basis of the sliding mode conplacement, and also for the position tracking control of desired trajectories with low-frequency sine and square waves.

• Composites Research
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• v.12 no.3
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• pp.45-54
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• 1999

In this paper, an experimental study on the buckling and postbuckling control of a laminated composite beam with eccentrically embedded SMA wire actuators is performed. For the purpose of enhancing the critical buckling load, buckling control is investigated through the use of reactive moment associated with the shape recovery force of SMA wire actuators. To improve the control authority for the buckling and postbuckling control of the SMA-composite beam, closed-loop control is used. The buckling and postbuckling control behaviours are presented and discussed qualitatively and quantitatively on loaddeflection plots considering the stacking sequence of the laminate, slenderness ratio of the beam and activation conditions of the SMA wire actuators. By maintaining the desired deflection shape with the proper reactive moment, buckling control can be extended to the postbuckling of the SMA-composite beam subjected to an external load.

• Journal of Digital Contents Society
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• v.18 no.7
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• pp.1451-1456
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• 2017

In this research we discuss an integrated actuator-control system for advanced control of a smart Shape Memory Alloy (SMA) actuator. Toward this goal, we designed and fabricated an actuator-control module combining two SMA actuating units with a single-chip microprocessor, two different sensing elements, and an actuator driver. In our proposed system, sensing elements include a 6-axis single-chip motion sensor for orientation measurement and a circuit for resistance measurement of SMA wires. We experimentally verified our proposed actuator-control system using actuator driving, sensor data readings, and communication tests.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.209-209
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• 2010

단위면적 당 메모리 집적도를 높이기 위해 플래시 기억소자의 크기를 줄일 때, 절연층 두께 감소에 의한 누설 전류의 발생, 단채널 효과 및 협폭 효과와 같은 문제 때문에 소자 크기의 축소가 한계에 도달하고 있다. 이러한 문제점들을 개선하기 위해 본 연구에서는 FinFET구조위에 Oxide-Nitride-Oxide (ONO) 층을 적층하여 2-비트 특성을 갖는 플래시 메모리 소자를 제안하였다. 소자의 작동전압을 크게 줄일 수 있으며 소자의 크기가 작아질 때 일어나는 단채널 효과의 문제점을 해결할 수 있는 FinFET 구조를 가진 기억소자에서 제어게이트를 제어게이트1과 제어게이트2로 나누어 독립적으로 쓰기 및 소거 동작하도록 하였다. 2-비트 동작을 위해 제어 게이트1의 게이트 절연막의 두께를 제어게이트2의 게이트 절연막의 두께보다 더 얇게 함으로써 두 제어게이트 사이의 coupling ratio를 다르게 하였다. 제어게이트1의 트랩층의 두께를 제어게이트2의 트랩층의 두께보다 크게 하여 제어게이트1의 트랩층에 더 많은 양의 전하가 포획될 수 있도록 하였다. 제안한 기억소자가 2-비트 동작하는 것을 확인 하기위하여 2차원 시뮬레이션툴인 MEDICI를 사용하여 제시한 FinFET 구조를 가진 기억소자의 전기적 특성을 시뮬레이션하였다. 시뮬레이션을 통해 얻은 2-비트에 대한 각 상태에서 각 전하 포획 층에 포획된 전하량의 비교를 통해서 coupling ratio 차이와 전하 포획층의 두께 차이로 인해 포획되는 전하량이 달라졌다. 각 상태에서 제어게이트에 읽기 전압을 인가하여 전류-전압 특성 곡선을 얻었으며, 각 상태에서의 문턱전압들이 잘 구분됨을 확인함으로써 제안한 FinFET 구조를 가진 플래시 메모리 소자가 셀 당 2-비트 동작됨을 알 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.262-264
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• 1999

본 논문은 IJG(Independent JPEG Group)의 JPEG 부호기의 처리 과정과 동작을 기술한다. IJG JPEG 부호기의 구조는 color conversion, downsampling, preprocessing 과정과 MCU 처리, FDCT, quantization, entropy encoding(sequential 혹은 progressive, huffman 혹은 arithmetic)의 실제적인 JPEG 압축 과정인 JPEG proper로 구성된다. 또한 이러한 모듈들외에 시스템 전체 controller, marker 생성기, 기억장소 관리, 에러 처리를 위한 모듈들을 포함하고 있다. 이에 본 논문에서는 IJG JPEG 부호기의 전체 시스템 구조 및 controller 와 주요 모듈간 인터페이스, 시스템에서 사용하는 주요 자료 구조에 대하여 분석하고자 한다.

• 발명특허
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• v.10 no.8 s.114
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• pp.64-64
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• 1985

금성반도체(대표 : 구자두)는 미국, 일본에 이어 세계 3번째로 첨단반도체제품인 CMOS 64K SRAM을 자체개발하는데 성공했다. 국내 최초로 개발된 금성반도체의 CMOS 64K SRAM은 우리나라의 반도체 기술수준을 선진국 수준으로 성큼 다가서게 했다. CMOS 64K SRAM은 NMOS의 256K DRAM에 비해 작동속도가 2배이상 빠를 뿐만 아니라 재충전이 필요없는 완전한 스태틱(static) RAM으로 대용량$\cdot$고속$\cdot$고신뢰성을 요하는 고성능 컴퓨터, 통신장비등 첨단 산업용 기기의 기억장치에 주로 사용된다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.146-149
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• 2003

Two-way shape memory effect(TWSME) under residual stresses are considered in the present study. The structure using two-way shape memory alloy(SMA) concept returns to its initial shape by increasing or decreasing temperature under the initially given residual stress. In the present study, we use a thermo-mechanical constitutive equation of SMA and laminated composite plates are considered as simple morphing structural components which are based on first order shear deformable laminated composite plate with large deflection. Numerical results of fully coupled SMA-composite structures are presented

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1145-1151
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• 2010

In this paper, we discuss the design and simulation of a jumping-robot mechanism that is actuated by SMA (shape memory alloy) wires. We propose a jumping-robot mechanism; the structure of the robot is inspired by the musculoskeletal system of vertebrates, including humans. Each robot leg consists of three parts (a thigh, shank, and foot) and three kinds of muscles (gluteus maximus, rectus femoris, and gastrocnemius). The jumping capability of the robot model was tested by means of computer simulations, and it was found that the robot can jump to about four times its own height. This robot model was also compared with another model with a simpler structure, and the performance of the former, which was based on the biomimetic design, was 3.3 times better than that of the latter in terms of the jumping height. The simulation results also verified that SMA wires can be suitable actuators for small jumping robots.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.133-140
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• 2005

If a Player car precedes from start to the end or a fuzzy car wins every day during computer or racing games, most players will lose their interest in the games soon after several times. In order to solve this Problem and increase amusement at racing games, the more important thing than anything else is decide the ranking. In this thesis, in order to give amusement In racing games, the researcher made a fuzzy car and made it race with player cars. Because the preceding fuzzy car runs ahead of player cars, it can recognize their behaviors according to change of following player cars' speed and distance, and the fuzzy car changes its memory, but doesn't enforce actual behaviors. If the fuzzy car would make decision, it has to do behaviors to compete the ranking on the basis of the contracts it has memorized under the situation where a timer is awarded. In addition, although an accompanying fuzzy car has different contents of memory, it is operated in the same way as mentioned above. At the time of experiments, the researcher applied the actual value to the test program and drew result for ranking competition. In conclusion, the researcher could confirm that we can have modeling of various behaviors by means of the method using fuzzy logic rather than simple if-then method.