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AN APPLICATION OF PROJECTIVE REPRESENTATION TO FINITE GROUPS

  • JEON, WON-GEE
    • Honam Mathematical Journal
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    • v.1 no.1
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    • pp.55-60
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    • 1979
  • 군(群)의 표현론(表現論)은 유한군(有限群)의 성질구명(性質究明)에 많이 이용(利用)되여진다. 이 글에서도 어떤 조건하(條件下)에서 p-Sylow 군(群) $S_p$가 order p을 갖는 두 개의 순회군(巡回群)의 곱으로 분해(分解)됨을 표현론(表現論)에 의하여 증명(證明)을 시도(試圖)한다(본문(本文) Thorem 7).

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LINEAR MAPPINGS ON LINEAR 2-NORMED SPACES

  • White Jr. Albert;Cho, Yeol-Je
    • Bulletin of the Korean Mathematical Society
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    • v.21 no.1
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    • pp.1-5
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    • 1984
  • The notion of linear 2-normed spaces was introduced by S. Gahler ([8,9,10,11]), and these space have been extensively studied by C. Diminnie, R. Ehret, S. Gahler, K. Iseki, A. White, Jr, and others. For nonzero vectors x,y in X, let V(x,y) denote the subspace of X generated by x and y. A linear 2-normed space (X,v) is said to be strictly convex ([3]) if v(x+y,z)=v(x,z)+v(y+z) and z not.mem.V(x,y) imply that y=ax for some a>0. Some characterizations of strict convexity for linear 2-normed spaces are given in [1,3,4,5,12]. Also, a linear 2-normed space (X,v) is said to be strictly 2-convex ([6]) if v(x,y)=v(x,z)=v(y,z)=1/3v(x+z, y+z)=1 implies that z=x+y. These space have been studied in [2,4,6,13]. It is easy to see that every strictly convex linear 2-normed space is always strictly 2-convex but the converse is not necessarily true. Throughout this paper, let (X,v) denote a linear 2-normed space.

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A Study on the Development of Thin Film Type Humidity Sensor Materials by Sol-Gel Method (III) (졸겔법에 의한 박막형 습도센서 소재개발에 관한 연구 (III))

  • You, D.H.;Kang, D.H.;Lee, E.H.;Yuk, J.H.;Jeong, S.Y.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 1995.07c
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    • pp.1162-1164
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    • 1995
  • In this paper, $TiO_2$-xmol%$V_2O_5$, x=0.0, 1.0, 2.0, 3.0 specimens are fabricated by Sol-Gel method. For the improvement of humidity sensitive characteristics for specimens, their microstructures are analysed and the optimum processing condition is established. Grain size increases with substitution rate of $V^{5+}$, on $Ti^{4+}$ site. Their humidity sensitive characteristics is good at 1mol% of $V_2O_5$ rate and heat-treated at $700^{\circ}C$. The capacitance of specimens decreases with frequency.

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Comparison of the Turf Performance of Bluegrasses, Fescues, Ryegrasses, and Zoysiagrass Under a Tree Shade (수목 그늘 환경에서 블루그라스속.훼스큐속.라이그라스속 및 한국잔디의 내음성 비교연구)

  • 김경남;남상용
    • Asian Journal of Turfgrass Science
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    • v.13 no.1
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    • pp.37-54
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    • 1999
  • This study was initiated to evaluate the seasonal turf performance in a tree shade and to suggest shade-tolerant turfgrasses suitable for domestic climate conditions. Atotal of 21 trufgrasses were tested, comprising of Korean lawngrass, shade-tolerant fine fescues, and newly-developed, shade-tolerant varieties of cool-season grasses. Dirrerences in shade tolerance were observed among varieties, species, and genera. Overall turf performance of C3 turfgrasses was better than that of C4 Korean lawngrass under a tree shade. Coarse-type fescues were excellent in shade tolerance, bluegrasses good, ryegrasses medium, fine-type fescues fair, and zoysiagrasses poor, respectively. Inter-species comparison in relative index of shade tolerance(IRST) demonstrated that tall fescue and fough bluegrass were greatest of 7.3, Poa supina 6.4, perennial ryegrass 5.0, Kentucky bluegrass 4.8, and fine fescues least, respectively. A great variation in RIST was observed with fine fescues; creeping red fescue was 3.6, chewings fescue 2.5, hard fescue 2.1, and sheep fescue 1.4, respectively. Among 21 turfgrasses evaluated, tall fescue 'Rebel Jr.', 'Era', and 'Oixie' and rough bluegrass 'Sabre' were the shade-tolerant varieties under a tree shade in Korea. Tall fescue, 'Rebel Jr.' was considered as the most shade-tolerant variety in the experiment. Fine fescues as creeping red fescue, chewings fescue, hare fescue, and sheep fescue, used as the shade-tolerant species in a cool climate of Europe and North America, were not suitable under domestic climate conditions.

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Modular approach to Petri net modeling of flexible assembly system

  • Park, T.K.;Choi, B.K.
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1992.04b
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    • pp.436-443
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    • 1992
  • Presented in the paper is a systematic approach to constructing a Petri net model of FAS (flexible assembly system). Petri net is widely used in modeling automated manufacturing systems. But, it found to be very difficult for an FA engineer to build a correct model of an FAS with Petri net symbols (ie, place, transition, and token) from the beginning. An automated manufacturing system in general is built from a set of "standard" hardware components. An FAS in particular is usually composed of assembly robots, work tables, conveyor lines, buffer storages, part feeders, etc. In the proposed modeling scheme, each type of standard resources is represented as a standard "module" which is a sub Petri net. Then, the model of a FAS can be conveniently constructed using the predefined modules the same way the FAS itself is built from the standard components. The network representation of a FAS is termed a JR-net (job resource relation net) which is easy to construct. This JR net is then mechanically converted to a formal Petri net (to simulate the behavior of the FAS). The proposed modeling scheme may easily be extended to the modeling of other types of automated manufacturing systems such as FMS and AS/RS.ch as FMS and AS/RS.

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A Study on the Design of Transverse Flux Linear Motor in Combination with the Magnetic Levitation and Guidance (자기부상 열차용 부상 및 안내 결합형 횡자속 선형 전동기 설계에 관한 연구)

  • Gang, Do-Hyeon;Kim, Mun-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.2
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    • pp.102-109
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    • 2000
  • The magnetically levitated system technology is highly expected to contribute the new transportation system of the 21st century with its high velocity operation, better riding comforts, friendliness to environment and saving of maintenance labour. Its development has been completed in low speed and in high speed application. In 2005, the Transrapid with 430 km/h speed will go into operation between Berlin and Hamburg[1]. In the year 2000, the realization of JR-Maglev will be basically evaluated for commercial operation[2]. In korea, maglev test vehicle with magnet for levitation and single sided linear induction motor for propulsion is under test at 1 [km] test track in KIMM.[3,4] Here, a transverse flux linear motor in combination with the levitation and the guidance leads to a considerable high power density and high efficiency simultaneously. The designed and measured performance of transverse flux linear motor for maglev system revealed a great potential of system mass reduction.

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Hydrochemical Characteristics and Changes by Rainfall in the Jungrang River (강우에 의한 중랑천의 수질 특성 변화 연구)

  • Kim, Youn-Tae;Kim, Yu Lee;Woo, Nam-Chil;Hyun, Seung Gyu
    • Journal of Korean Society on Water Environment
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    • v.22 no.4
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    • pp.666-671
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    • 2006
  • Effects of a rainfall event (July 28, 2005) on the hydrochemical characteristics of the Jungrang river, the biggest tributary of the Han river, was investigated. Significant spatial variations in the hydrochemical characteristics were observed. At JR2 location, concentrations of T-N and T-P were relatively low indicating occurrence of active oxidation in the stepped drop structure. At JR3 location, concentrations of Na, K, Cl, $NH_4-N$ and EC were elevated suggesting increased discharge from the nearby waste-water treatment plant and tributaries. The rain event diluted major dissolved ion concentrations in the river by 12~52%. The $NO_3-N$ levels were preserved during the rain then increased about twofold after rainfall, suggesting increased discharge of nitrate-contaminated groundwater. Heavy metals including Cd, Co, Cr, Cu and Pb were not detected in all water samples and the leachates from surface sediment samples. Concentrations of Fe, Mn, Al and Zn were below the Korean Drinking Water Guideline. Results of this study suggested that establishment of water-quality monitoring protocols describing temporal and spatial variations in parameters sensitive to rainfall events, relatively steady factors, and contaminant sources is required.

A study on Dielectric and Electrical Properties using PMN Ceramics with $La_{2}O_{3}$ substitution ($La_{2}O_{3}$ 치환된 PMN계 세라믹스의 유전 및 전기적특성에 관한 연구)

  • Ji, S.H.;Kim, B.S.;Lee, N.H.;Lee, H.K.;Kim, Y.H.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1621-1623
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    • 1996
  • The dielectric and polarizable properties of 0.85Pb$Mg_{1/3}Nb_{2/3}$)$O_3$-$0.125PbTiO_3$-$0.25BaTiO_3$ Ceramics have been investigated as a addition of the amount of $La_{2}O_{3}$($0{\leq}x{\geq}0.05$). The Temperature-dependant electrostictive characteristics of 0.85PMN-0.125PT-0.25BT relaxor ferroelectic system were improved by enhencing the extent of the diffuse phase transition(DPT). This was achieved using PMN-PT-BTceramics by the partial substitution of La at the Pb site. The curie temperature and the maximum dielectic permittivity decreased by substituting $La_{2}O_{3}$ and the electic field-related hysteresis phenomena decreased with increasing $La_{2}O_{3}$ substitution amount. It is showed decreasing in induced strain for electric field with increasing $La_{2}O_{3}$ substitution.

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