지식 기반 시스템을 이용한 Draw Die 설계 자동화에 대한 연구

허원 公州大學校工科大學生産技術硏究所 1994 論文集 Vol.2 No.-

설계와 생산을 연계하려는 목적으로 단순한 도면만의 CAD가 아닌, 생산과 설계의 기능을 포함하는 지식 요소들을 함축시켜 표현하려는 지식 기반 공학의 접근 방법이 지향되고 있는데, 이는 설계자와 생산자의 know-how를 정형화하는 것을 의미한다. 본 논문은 금형 설계의 한 분야인 Draw Die 의 설계를 자동화하기 위하여 개발된 지식 기반 공학을 이용한 생산 모델을 소개하고 그 설계 결과를 보여주고자 한다. Designers and manufacturers are paying attention to Knowledge-based engineering, which represents not only the geometric entities but also general knowledges for design and manufacturing. The formulation of the knowledge about manufacturer's and designer's know-how is the key of the knowledge-based engineering. In this paper, a product model for draw die design automation is developed and the design results are presented.

실리콘 IC에서 정사각-나선형 인덕터의 컴퓨터를 이용한 설계

조현묵 公州大學校工科大學生産技術硏究所 1996 論文集 Vol.4 No.-

Planar inductors have been implemented in practical systems for many years using a variety of substrates. In the early development of Si IC's, planar inductors were investigated but the prevailing lithographic limitations and relatively low frequencies of operation led to their abandonment as impractical due to excessive chip area requirement and low Q. This paper describes a computer program developed for calculating inductances for square geometries, the variables considered being track width, space between tracks, and number of turns. Although, the effects of film thickness and frequency on the mutual-inductance parameter are discussed.

주파수 영역 표면과 시험법(SASW)을 이용한 수중 콘크리트의 강도측정

이병식 公州大學校工科大學生産技術硏究所 1997 論文集 Vol.5 No.-

A study is conducted to apply Spectral-Analysis-of-Surface-Waves(SASW) method to non-destructive evaluation of the strength of underwater concrete. Experimental dispersion curves of surface waves for the concrete are determined using SASW method. Strength of the concrete is, then, evaluated thorough a forward modeling process using theoretical solutions of wave propagation. As a result, it is found that theoretical dispersion curves determined using the 3-D solution simulate more appropriately the experimental dispersion curves than those obtained from the 2-D solution. However, it is concluded that continuous studies in both experimental and theoretical aspects are still required to establish applicability of the SASW method to non-destructive evaluation of the integrity of underwater concrete structures.

고속의 획득시간을 갖는 새로운 디지털 위상동기루프

조현묵 公州大學校工科大學生産技術硏究所 1996 論文集 Vol.5 No.-

A new kind of digital phase-locked loop(DPLL) is proposed, which consist of a modified 9-gate phase detector, a frequency multiplier and a loop filter. All of them are implemented in digital hardware without any analog component. The proposed DPLL has very fast lock-in speed and belongs to type II system and the shortcoming of the DPLL is that it enlarges phase noise by a factor of about 1.26. Because there is no analog element used and the circuit is not too complicated, the PLL can be integrated into one chip. With some improvement the loop candkfj have very wide acquisition range such as on the order of 10⁴or more.

JAVA를 이용한 동기기 교육, 설계 패키지 개발에 관한 연구

허원,김영민 公州大學校工科大學生産技術硏究所 1996 論文集 Vol.5 No.-

There have been great advances in communication and networking in recent times. It is necessary to take advantage of this information infrastructure for the purpose of developing an engineering education system. But the networking system was expensive or hard to develop. The current international networking is converging to the use of the World Wide Web system. It has become a new standard for global network communication. But there are not a great number of applications which take full advantage of this environment. In this paper, an interactive education system for engineering education using the World Wide Web will be presented. This can be used as a supplementary kit for engineering education of synchronous machine design. The system is developed using JAVA and can be accessed using Web browsers.

빙축열시스템의 냉방부하예측 기법

이윤섭 公州大學校工科大學生産技術硏究所 1998 論文集 Vol.6 No.-

In summer days, the electrical peak demands by the cool loads in many buildings causes the serious problems in electrical power companies. The ice storage systems is being applied in order to reduce the peak demands in many buildings. The forecasted cool load in a buildings is necessary for optimal operation of ice storage systems. This paper presents the algorithm of cool load forecast for ice storage systems. For the cool load forecast, the algorithm of forecast for the weather informations such as temperature, humidity is suggested and the algorithm for cool load forecast is suggested. The results of simulation for the performance of each algorithms are also presented.

고품질 적층 세라믹 콘덴서 응용을 위한 강유전체 복합 재료연구

김남철 公州大學校工科大學生産技術硏究所 1999 論文集 Vol.7 No.-

The multilayer ceramic capacitors (MLCC) are fast growing as the result of the continuing miniaturization of integrated electronic components. Among ceramic materials, modified BaTiO₃ based ceramics are widely used for MLCC. However, there are still some limitations, such as high firing temperature, strong dependency of DC field, moderate dielectric constant, and an unstable temperature coefficients of capacitance (TCC). One family of materials which have received a large amount attention are the lead based relaxor ferroelectrics due to their super-high dielectric constant, even though they have some disadvantages for MLCC, such as non-stoichiometry structure due to the volatility of lead, strong frequency dependency of dielectric constant, and high dielectric loss. A new approach which has been used to produced a material with temperature stable dielectric characteristics with high dielectric constant is to make composite dielectrics between modified BaTiO₃ and relaxor. In this work, several relaxor-normal ferroelectric composite systems were examed to adopt for MLCC applications. Based on the results, MLCCs produced show low firing temperature, high dielectric constant, CR product, good TCC characteristics, and moderate DC bias saturation, promising candidate materials for miniaturizing MLCC.

GaAs 부동전자채널 전계효과 트랜지스터의 전기적 특성

권영세,김창태 公州大學校工科大學生産技術硏究所 1993 論文集 Vol.1 No.-

본 연구에서는 새로운 GaAs 트랜지스터인 부동전자 채널 FET를 제안하고 제작 결과를 보였다. 선택적 유기금속화학증착법을 이용하였으며 채널을 삼각형 빈공간의 바로 위에 형성시킴으로써 유효케이트 길이를 줄일 수 있는 구조를 가진다. 선택적 결정성장 특성을 알아보았고 이론적 모델을 제시하였다. Schottky 및 p-형 게이트를 가진 소자의 DC특성을 보였으며 저잡음 소자 및 DCFL의 단위소자로서의 응용 가능성을 보였다. We have fabricated a new GaAs FECFET(Floated Electron Channel FET) and have used selective MOCVD technique for device fabrication. Because the active channel is formed on the triangular void, the device has very short channel length. We have also characterized and modelled the facet shapes of the overgrown layer in selective MOCVD. Finally the DC output characteristics of the two FECFET with Schottky and p-type gate are described. We think that this device can be applied to the low noise FET or an unit device of DCFL.

단일 주파수 다이나믹 CMOS POS PLA의 설계에 관한 연구

동용배 公州大學校工科大學生産技術硏究所 1993 論文集 Vol.1 No.-

이 논문은 단일 주파수로 동작하는 다이나믹 CMOS PLA의 두가지 형태에 대해서 설명한다. 이 PLA (Programmable Logic Array) 들은 triggered 디코더와 전하 분할(charge sharing)기술을 이용한 것으로 고속, 저전력 소모특징을 갖는다. Triggered 디코터 사용에 의하여 기존 PLA에 있는 ground 스위치를 제거할 수 있으며 동작 속도를 증가 시킬수 있다. 전하 분할 기술의 사용에 의하여 csscading AND 게이트를 실현 할수 있다. 2.0um CMOS PLA 의 두가지 형태가 시뮬레이션 되었고, 이들의 결과는 기존 PLA의 속도 및 전력에서 우수함을 보였다. Triggered 2-bits 디코더를 사용한 2-POS PLA는 기존 PLA보다 1.8 및 2.2 배 빠르다. 48 입력 minterm 및 8 출력 minterm을 갖는 일반 PLA 경우에 POS 및 2-POS PLA 는 2.2 및 3.4 배 적은 전력 소모를 갖는다. This paper presents two types of single phase dynamic CMOS NOR-NOR PLA. The PLAs use triggered decoders and charge sharing resulting in high speed circuits with low power dissipation. By using triggered decoders, ground switches can be eliminated, thus making this new design much faster and dissipate less power than single phase conventional CMOS PLAs. By using charge-sharing, a cascading AND gate can be implemented. The two types of 2. Oum CMOS PLA were simulated and their resulting delay-times were much less than that of a conventional single phase CMOS PLA. The POS PLA using triggered 1-bit decoders(three-valued logic)and the POS PLA using triggered 2-bit decoders are respectively, 1.8 and 2.2 time faster than the conventional PLA. For a typical PLA with 48 input minterms and 8 output minterms, and they have respectively, 2.2 and 3.4 times less power dissipation than the conventional PLA.

다공질 실리콘 산화막의 형성기구 및 계면특성

최복길 公州大學校工科大學生産技術硏究所 1993 論文集 Vol.1 No.-

HF용액내에서 양극 반응에 의해 형성된 다공질 실리콘층(PSL)의 특성을 조사하고 다공질 실리콘 산화막(OPS)의 형성 기구와 계면 특성을 규명하였다. SIMS분석을 통한 PSL의 밀도는 표면보다 PSL-Si 계면이 높으며 산화 반응이 PSL의 표면 및 내부의 세공 표면에서 균일하게 이루어진다. OPS막은 열산화 Sio₂에 비해 큰 프랫밴드 전압과 고정 전하 밀도를 나타내며 dlts법으로 측정한 OPS막의 포획 단면적과 계면 상태 밀도는 각각 10?㎠와 10?-10?eV?의 범위이다. The properties of porous silicon layer(PSL) formed by anodic reaction in hydroffluoric acid solution have been studied. Ferther, the formation mechanism and interface characteristics of oxidized porous silicon(OPS) film are reported. It is shown from SIMS analysis that the porous silicon nera the surface has a lower density than that near the PSL-substrate interface and that oxidation is performed uniformly through PSL. OPS film shows higher flat-band voltage and fixed charge density than thermally grown SiO₂ film. The capture cross-section and the interface states density of OPS film determined by DLTS method are of the order of 10?㎠ and 10??-10??cm?eV?? respectively.