아날로그 협대역화 기술

林東民 慶尙大學校生産技術硏究所 1993 生産技術硏究所論文集 Vol.9 No.-

With the increasing demand for the radio spectrum in mobile communications, the lack of the available radio spectrum is now a severe problem. To cope with the spectrum shortage, the spectrum-efficient analog technology has been developed and the single sideband (SSB) has attracted considerable attention as a possible solution. Two typical VHF/UHF band SSB's, amplitude companded SSB and real zero SSB, are described and their performances are discussed briefly.

Fuzzy LP에 의한 製造業의 適定 用地 規模의 推定 : Focused on Kyeongnam Province 慶尙南道를 中心으로

이백호,문태헌 慶尙大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.13 No.-

These days, the manufacturing lands have been supplied without consideration of necessary conditions such as labor, water, electrical power and environment. Thus, some industrial complexes suffer difficulties in maintenance. In the long term, the appropriate amount of manufacturing lands must be estimated within the limits of these various constraints. A new approach using the fuzzy linear programming is proposed for the estimation of the appropriate amount of manufacturing lands with constraints under uncertain circumstances in the future. A characteristic of the proposed approach is that the fuzzyness of labor, water, electrical power and industrial land in the future can easily be taken into account by fuzzy linear programming. The aim of this paper, therefore, is to develop a method and estimate the appropriate amount of manufacturing lands. To achieve the goal, fuzzy linear programming was introduced. In this paper, the objective function to be optimized was formulated to maximize value-added, and constraints are the conditions such as labor, water, electrical power and industrial land.

표준시간자료의 산정 : A Comparison between Two Different Production Types 소품종 대량생산과 다품종 극소량생산 형태의 비교

변재현,심창건 慶尙大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.13 No.-

This paper considers the estimation and application of the standard time data depending on the types of production systems. Two types of production systems, that is, few-item large quantity and multi-item extremely small quantity procuction types are compared. We investigate limitations of applying the standard time estimation methods and propose ways of improving the current situation. Two case studies are included.

경상대학교 시설장기발전계획의 시설배치계획에 관한 연구(Ⅰ) : The Case on the GaJwa Campus 가좌캠퍼스 시설배치계획

李相正,金奭圭 慶尙大學校生産技術硏究所 1999 生産技術硏究所論文集 Vol.15 No.-

The purpose of this study is a planning of GyeongSang National University Master Plan on academic plan(1995-2004). The contents of this study are the space program by analysis of academic plan, physical environments analysis of campus, direction and concept of space program, and the establishments of basic direction - layout, architectural arrangement, traffic.

성형 네트워크에서의 질의 처리를 고려한 화일 분배 정책에 관한 연구

이민호,김철 慶尙大學校生産技術硏究所 1988 生産技術硏究所論文集 Vol.4 No.-

컴퓨터와 통신기술의 발달로 분산 데이타베이스 체계가 중앙집중식 데이타베이스 체계보다 선호되는 경향이 있다. 분산 데이타베이스 체계에서 나타나는 문제중의 하나가 어떤 컴퓨터에 어떤 화일을 보관할 것인가를 결정하는 문제이다. 본 논문에서는 중앙에 마스터 화일을 갖고 있는 성형 네트워크에서의 화일 분배 문제를 다룬다. 기존의 대부분의 연구에서는 하나의 화일만을 접근하는 질의를 고려하였지만, 본 논문에서는 여러개의 화일을 접근하는 질의를 고려하였다. 이 문제를 0-1 정수계획법으로 모형화하였고 라그랑즈 탐색기법으로 문제를 해결하였다.

화력과 양수 발전소의 최적운영계획을 위한 라그란쥐완화기법

이민호 慶尙大學校生産技術硏究所 1987 生産技術硏究所論文集 Vol.3 No.-

전력의 생산은 수요를 충족시키면서 전체소요비용을 최소화 시키는 방법으로 운영방식을 결정하여야 한다. 그러나 문제의 성격상 원자력, 수력, 화력, 양수발전 등 모든 발전기의 운영을 동시에 고려하는 최적화 모형은 문제의 크기가 방대하여 기존의 방법으로는 해결이 불가능하다. 본 논문에서는 원자력과 수력발전은 기존의 운영방식에서 기저부하(base load)를 담당하고 이외의 변동이 심한 부하는 화력과 양수발전을 적절히 운영하여 수요를 충당한다는 점을 이용하여, 이 두 종류(화력, 양수) 발전기의 발전계획을 최적화하기 위한 방안을 모색하였다. 제안된 모형을 완화(relaxation)시킨 후 얻어진 화력발전기에 대한 문제는 최단경로문제의 해법에 의해 해결되며, 양수발전기의 운영에 대한 문제는 최소비용흐름 문제의 해법으로서 해결하였다. 예제로 한국전력의 1980년 8월 8일부터 1980년 8월 15일까지의 자료를 이용하여 39개의 화력발전기와 1개의 양수발전기 운영의 결과를 제시하였다.

2ⁿ정책하에서의 통합 생산재고모형

김경모 慶尙大學校生産技術硏究所 1987 生産技術硏究所論文集 Vol.3 No.-

주기에 2ⁿ제약을 가한 joint replenishment 문제를 위한 Jackson, Maxwell, 그리고 Muckstadt의 해법을 2ⁿ제약이 있는 통합생산재고모형에 적용할 수 있도록 수정하였다. 수정된 해법의 적용성을 예제를 통해 보였다. 제시된 해법은 2ⁿ제약을 가하지 않은 최적해의 6%(비용측면)내에 있음을 알 수 있다.

비수계 분산중합에 의해 제조된 PMMA Seed-core 입자의 Surface Morphology

許南禎,李基昌 慶尙大學校生産技術硏究所 1995 生産技術硏究所論文集 Vol.11 No.-

Various types of non-aqueous acrylic dispersion particle were prepared by 2 stage dispersion polymerization in aliphatic hydrocarbon media. The surface morphology and the degree of wrinkles of the resulting PMMA seed-core particles were found to be greatly influenced by polymerization parameters, such as polymerization process, initial amount of AIBN. EGDMA concentration, feeding time of monomer mixture and polymerization temperature at the second-stage polymerization. The reaction conditions for formation of the "raisin-like" particles were found to be semi-continuous process in the presence of 0.29g EGDMA cross-linker and 0~0.0llg AIBN as a initial catalyst in second-stage polymerization using butyl-rubber stabilized PMMA seed latex. The surface morphology of the PMMA seed-core particles, prepared using butyl rubber stabilized PMMA seed panicles, was found to be greatly influenced on the initial amount of AIBN, mode of polymerization process, amount of cross-linker, feeding time of monomer mixture, and polymerization temperature. In semi-continuos process, when the initial amount of AIBN used in second-stage was in range of 0 ~ 0.011g. the resulting PMMA seed-core particles showed deeply wrinkly, raisin-like appearance. On the other hand, when the initial amount of AIBN was 0.11g, degree of wrinklesof the PMMA seed-core particles was significantly decreased. The degree of wrinkles on the particle surface of the PMMA seed-core particles, ingeneral, showed a tendency of decrease with increasing AIBN concentration as a initial catalyst in second-stage polymerization. The degree of wrinkles on the panicle surface of the PMMA seed-core particles as EGDMA concentration was decreased with going away from 0.29g EGDMA cross-linker concentration. The degree of wrinkles of the resulting PMMA seed-core particles was found to be increased with increasing the feeding time of the monomer mixture. The PMMA seed-core particles prepared at 105℃, were found to be well separated-stable latexes independent of presence or absence of EGDMA. On the other hand, the latexes prepared at reaction temperatures lower than 105℃ and only in the absence of EGDMA cross-linker were found to be all stable. In cases of the preparations with EGDMA, gelation of the PMMA seed-core particles was occurred with formation of lots of secondary nucleated small particles. In batch process, the initial amount of AIBN was little effect on the exterior morphology of PMMA seed-core particles. At 0.29g EGDMAcross-linker, all coagulated latexes with the occurrence of secondary nucleated small particles were formed. Although numerous ?? as to the detailed mechanism of particle nucleation and growth in dispersion polymerization havebeen proposed, no generalized conclusions have been drawn. It is ?? that the butyl rubber-stabilized PMMA seed particles, prepared in this study, have an interpenetrating network(IPN) structure, with the butyl rubber component of the PMMA-butyl rubber graft copolymer forming aninterconnecting network throughout the interior of the PMMA seed particles. This IPN structure in the PMMA seed particles could be important factor in controling the surface morphology of the PMMA seed-core particles prepared under various reaction conditions described above. We do not have the detailed mechanistic solutions to the experimental results obtained in this study at the moment. More work should be done on this subject.

適應 要素 分割을 위한 새로운 節點 追加 앨고리즘 : 線形 解析 Linear Case

辛興敎 慶尙大學校生産技術硏究所 1994 生産技術硏究所論文集 Vol.10 No.-

This paper presents the error estimation and node adding algorithm that applicable to the adaptive mesh refinement for the electromagnetic field analysis by finite element method. If this algorithm is used for the mesh generation, the analyzing results are purchased so fast with ease without complicated process of the calculations about the tangential and normal components of the flux density and the field intensity on the elements sides. The supplement of this algorithm and the application to the real models are expected.

카올린으로부터 용융 Al의 SiO₂에 대한 선택적 침식을 이용한 Al₂O₃-Al 복합체의 제조

배원태,박민준,박외철 慶尙大學校生産技術硏究所 1994 生産技術硏究所論文集 Vol.10 No.-

½By the use of selective corrosion reaction of molten Al with the SiO₂, Al₂O₃-Al co-continuous ceramic-metal composite was prepared. The optimum conditions to provide maximum value of the mechanical properties such as flexual strength' and fracture toughness has been investigated. The preform was formed at 250㎏/㎝²pressure, fired at 1400℃, and subsequently soaked for 1 hour. The preform corroded with molten Al at 1000℃ for 24 hours had the highest value of mechanical properties. This material showed the bulk density of 3.25g/㎤, 4-point MOR of 280 Mpa, and ?? of 8 MPa. ??. The calculated relative density of the final product consisted of about 50 wt% of aluminum was approximately above 97,5%. If the content of alumina, which provides stiffness, was increased, flexural strength of this material will be greatly imporved. Then the practical applications for brake rotors, piston crowns, cylinder liners, etc. would be expected.