• Industrial Engineering and Management Systems
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• v.4 no.2
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• pp.117-122
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• 2005

An assembly system (AS), a valuable tool for mass production, is generally composed of a number of workstations and a transport system. While the workstations perform some preplanned operations, the transport system moves the assemblies by special designed pallets from one station to another. One common problem associated with automatic assembly systems is that some assembly operations may have relatively long cycle times. As a consequence, the productivity, as determined by the operations with the longest cycle time, can be reduced significantly. Therefore, special forms of parallel workstations were developed to improve the performance of an assembly system. In this paper, three most commonly used parallel stations: on-line, off-line and tunnel-gated stations in a free transfer assembly system are studied via discrete event simulation. Our findings revealed that the off-line parallel system has the best performance because the two independent parallel stations can lower the buffer requirement; reduce the sensitivity to variability of processing time and balance of a line. On-line parallel systems were found to have a relatively poor performance, because the operations of two parallel stations block each other, and higher buffer capacity is required to achieve similar capacity. The tunnel-gated system was more efficient than the on-line system since the first parallel station can operate independently. More importantly, we have quantified the productivity of the three different strategies mentioned. Engineers can choose the optimal strategies for installing parallel stations under their working environment.

• Land and Housing Review
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• v.11 no.1
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• pp.39-48
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• 2020

Main research question of this study is about whether gated community (GC) as private urban governance gets along with local public goods by locating near to them. We examine this question through testing the Tiebout hypothesis from case study of Seoul, capital city of South Korea, in which GCs are so common to test the assumption empirically. For this, we examine the meaning of GC in 3 Es viewpoints; conceptualize the framework of Tieboutian co-evolution of GC and local public goods by hedonic price modeling. As a result, possibilities are found that GCs are to be seen from different point of view, viz. co-evolutionary mechanism between private and public governance; GCs effectively capture and represent the demand of residents for local public goods through voting by their collective locational choice. It allows us different kind of approach to investigate APTs as a co-evolutionary form of private and public urban order rather than seeing them only as a tool of speculative investment, particularly in rapidly urbanizing countries like Korea.

• Journal of the Korean Geographical Society
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• v.39 no.3
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• pp.374-390
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• 2004

This research analyzes the differentiation of the reproduction of the educational capital according to the residential area which is determined by the socio-economic status of parents. The results of the research show that: the reproduction of the educational capital of the region where highly educated people are segregated is very different from that of other regions in terms of the quantity and quality. The fact that one resides in a certain special area tends to determine the future of his child, so the boundary between the social groups is being intensified through the geographic concentration of the affluence and poverty. Gangnam Gu where the different educational capital is reproduced through the better educational environment tends to become the gated city which has the invisible but strong socio-economic barriers through the sharp rise of the housing(apartment) value and the concentration of highly educated people. Through the exclusion of other classes by the high price of the housing, only the residents within the barrier have access to the good educational facilities and services.

• Proceedings of the KGS Conference
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• 2004.05a
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• pp.88-88
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• 2004

본 연구에서는 부모세대의 사회ㆍ경제적 지위에 따라 결정된 거주지에 따라 자녀세대의 학력자본이 차별적으로 재생산되고 있는지를 살펴보았다. 연구결과 고학력으로 대표되는 사회ㆍ경제적 지위가 높은 집단의 거주 비율이 높은 분리된 거주지에서 재생산되는 학력자본은 양적인 면에서나 질적인 면에서 모두 매우 차별적인 것으로 나타나고 있다. 과거에 비해 대학진학률이 많이 높아졌지만 4년제 대학 진학으로 제한해 지역별 학업 성취를 비교해 보면 지역별 차가 뚜렷하게 나타나고 있다. (중략)

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1694-1696
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• 1996

Charge formation in filled ethylene propylene diene terpolymer (EPDM) compound has been investi gated. Homocharge was found in pure crosslinked EPDM. The homocharge decreased with the increased of ATH content in EPOM while increased with the increase of clay in EPDM.

• Journal of English Language & Literature
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• v.58 no.4
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• pp.655-678
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• 2012

Doris Lessing, who considers science and technology as instruments of capitalism, deals with the theme of 'biological evolution' in The Sirian Experiments, the third book in the Canopus in Argos: Archives series. One of her themes that repeats throughout is that of 'spiritual evolution,' and in The Four-Gated City she even used 'biological evolution' as its metaphor. This paper analyzes The Sirian Experiments using scientific knowledge such as the concept of 'biological evolution' from Charles Darwin's evolution theory and Edward O. Wilson's sociobiology. Lessing concludes that while 'biological evolution' not accompanied with 'spiritual evolution' puts humans in existential problems and mental breakdown, the one in equilibrium with the other can bring social and political revolution. Lessing's concept of 'spiritual evolution' is basically a product of her holistic view and her own philosophical view that human evolution is a necessary process following the Universal Order, which shows that she is influenced by Sufism. The basic tenet in Sufi philosophy is to achieve equilibrium between the rational and non-rational modes of consciousness. Lessing incorporates her rational and irrational ideas into The Sirian Experiments to make a field for confluence where the biological, the sociological, and the spiritual thinking converge.