• Journal of Korean Society of Transportation
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• v.12 no.1
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• pp.43-54
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• 1994

The major concern of this paper is to investigate the properties of a stochastic equilibrium for each model system in terms of a consumer welfare measure. The primary assumption for this study is that a trip-maker would choose the trip from his origin zone which maximizes his personal welfare. This assumption, finally, leads to a singly constrained gravity model. The consumer welfare measure is derived from the concept of expected welfare of randomly sampled trip-makers. Each of the four different models considered in this paper is differentiated depending on the complexity of its model or the definition of its travel function. In this study, three different regions are chosen for the purpose of taking into account the effects of different zone-systems on the properties of a stochastic equilibrium : (i) Archerville region (5 zone) ; (ii) San Francisco Bay regions (30 zones) ; (iii) Houston, TX region (199 zones). It is concluded that almost identical, "global" consumer welfare values can be obtained in some cases of the gravity-type trip distribution models based on a stochastic equilibrium.

• Journal of the Korean Geographical Society
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• v.38 no.5
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• pp.659-666
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• 2003

This study is a comparative analysis on the variabilities of spring precipitation and atmospheric circulations of 500hPa surfaces between dry years and wet years over the Korean Peninsula. The distribution of variabilities of precipitation in spring are different from month to month. In March, the pattern is west-high and east-low, in April, north-high and south-low, in May, east-high and west-low respectively. In the distribution of 500hPa geopotential height anomaly, dry years of March show west-high and east-low pattern in that negative anomaly zones are formed around the Korean Peninsula and western coast of the northern Pacific Ocean, and positive anomaly zones are formed in the inland of East Asia centered on Siberia. Consequently, the Korean Peninsula and neighboring regions experience dry season when the zonal flows are strong with the positive anomaly zones of zonal components. On the contrary in the wet years the westerlies are weak since the pattern is east-high and west-low in which the positive anomaly zones are formed over the Korean Peninsula centered on the Aleutian Islands and western coast of the northern Pacific Ocean and the negative anomaly zones are formed in the inland of East Asia centered on Tibet Plateau and Siberia. The dry years of April and May show north-high and south-low patterns in that negative anomaly zones are found from the center of the northern Pacific Ocean to the eastern coast of East Asia, and the positive anomaly zones are found in the center of East Asia extending from Aleutian Islands to Tibet Plateau. On the contrary, in the wet years the patterns show south-high and north-low. This study identified not only that there are contrary atmospheric circulation patterms between dry years and wet years over Korean Peninsua in spring, but also there are different atmosphric circulation patterns between early and late spring.

• Journal of the Korean Society of Safety
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• v.2 no.3
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• pp.21-27
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• 1987

The effect of plastic deformation in an interfacial crack is considered. Yield zones are assumed to have the form of a strip along the interface. The crack is subjected to mode III loads at infinity and lies along the interface of two semi-infinite planes with different material properties. The size of the yield zones, the relation between the size of the yield zone and CTOD are obtained in a closed form solution. The J integral also can be obtained in a closed form Solution.

• Architectural research
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• v.14 no.4
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• pp.117-124
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• 2012

High rise office buildings represent one of the most energy-intensive architectural typologies. The growth of urban population necessitates sustainable high rise towers that lessen environmental impacts and energy consumption. Among various sustainable strategies, the integrated design is long known to be an important process that has great impact on building's sustainability. The framework for this paper is based on the case study of integrated towers that are located in different climate zones. The paper specifically addresses to what extent climate conditions influence the design of a high rise building and what kinds of the climate integrated design has been implemented. Qualitative case studies were carried out using published data and architectural drawing set. The technical work presented in the paper is based on computer simulation that examines the insolation analysis using hourly recorded weather data. The analysis results revealed that the site and building envelope integration and the site and building service systems have shown the most frequently employed in the integrated towers through the implementation of renewable resource integration, high performance envelopes and sustainable building service systems. Internal comfort and further energy saving in the integrated towers are offered through an automatic building management system. Due to the dynamic climate conditions, integration of building systems requires a sophisticated approach to building sustainability.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.283-289
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• 2004

The number of pixel defects including bright and black dots on a panel is one of the critical factors determining the quality of TFT-LCD. Since pixel defects on the TFT-LCD panels are sometimes unavoidable, manufacturers have to inspect the panels so that any panel with an unacceptable number of defects will not be delivered to the buyers. However, the buyers demand for the manufacturers to meet different pixel defects tolerances (acceptable number of pixel defects on a TFT-LCD panel) around central(tight) and peripheral(loose) inspection zones. The disagreement in quality standard among different buyers also cause confusions in screening non-confirmative products and unstable yield of production. Few research has focused on the effects of defect locations on a TFT-LCD panel on their detection probabilities and the rational division of defect inspection zones. In this research, experiments were conducted to find the detection probabilities of black dot defects with respect to their varying locations on a TFT-LCD. It is proposed a rational division of inspection zone on a TFT-LCD panel on the basis of detection probabilities of the defects. With these division of inspection zones and the mean defect detection probability within each zone, it is expected to establish a more reasonable pixel defects tolerances.

• Steel and Composite Structures
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• v.32 no.4
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• pp.423-441
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• 2019

This study aims to accurately predict the first ply failure loads of laminated composite hypar shell roofs with different boundary conditions. The geometrically nonlinear finite element method (FEM) is used to analyse different symmetric and anti-symmetric, cross and angle ply shells. The first ply failure loads are obtained through different well-established failure criteria including Puck's criterion along with the serviceability criterion of deflection. The close agreement of the published and present results for different validation problems proves the correctness of the finite element model used in the present study. The effects of edge conditions on first ply failure behavior are discussed critically from practical engineering point of view. Factor of safety values and failure zones are also reported to suggest design and non-destructive monitoring guidelines to practicing engineers. Apart from these, the present study indicates the rank wise relative performances of different shell options. The study establishes that the angle ply laminates in general perform better than the cross ply ones. Among the stacking sequences considered here, three layered symmetric angle ply laminates offer the highest first ply failure load. The probable failure zones on the different shell surfaces, identified in this paper, are the areas where non-destructive health monitoring may be restricted to. The contributions made through this paper are expected to serve as important design aids to engineers engaged in composite hypar shell design and construction.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.11a
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• pp.137-140
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• 2002

To determine if fish density, biomass, species richness, and species diversity were greater in ecotone than the stream and littoral zones, I sampled fish monthly in the Ledbetter Creek through Ledbetter Creek Embayment in Kentucky Lake, Kentucky, from April to October 1996 by using throw traps. During the first four months (daytime only) fish density did not vary significantly among zones or among months. However, there were significant differences among zones during the last three months and the stream zone had significantly higher mean fish density than both the littoral zone and the ecotone. Fish biomass also differed significantly among zones during the last three months. The stream zone had the highest mean fish biomass among zones, significantly higher than the ecotone, but not different than the littoral zone. There were no statistically significant differences among zones during the first four months, but mean fish biomass in the stream zone was about eight times higher than the ecotone, The stream zone had the highest fish species richness among zones. Differences were significant among zones during the last three months, and the stream zone (0.98 $\pm$ 0.04) had significantly greater mean fish species richness than the ecotone (0.45 $\pm$ 0.01), but not significantly than the littoral zone (0.56 $\pm$ 0.17). Fish species richness differed significantly among months during the first four months, Monthly species diversities ranged from 0.62 to 1.96 in the stream zone, 0 to a.57 in the ecotone, and 0 to 2.60 in the littoral zone. Combined species diversities in the stream, the ecotone , and the littoral zones were 2.72, 3.58, and 3.10, respectively, There were five families of fishes captured frequently enough for their individual numbers to comprise at least 8 % of the total. Family rankings in the stream zone were opposite of the littoral zone. Percidae was the most abundant family and Clupeidae was absent in the stream zone, whereas Percidae was uncommon and Clupeidae was the most abundant family in the littoral zone. Atherinidae was dominant in the ecotone. Five of the most abundant species comprised 65 % of the total number. The guardian darter occurred only in the stream zone, and it was consistently found in riffles. Longear sunfish and central stoneroller also had significant differences of mean fish densities among zones, and they were found mostly in the stream zone. Threadfin shad and bullhead minnow were almost exclusively caught in the littoral zone. I finally concluded that the ecotone between the stream and the littoral zone in this small-scale freshwater aquatic ecosystem was not as productive as the ones in other ecosystems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.558-564
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• 2016

The network interference gives positive and negative effects to security and QoS simultaneously by disturbing the decoding of receiver and eavesdropper. The transmission of artificial noise enables to indirectly control these contradicting effects. This paper proposed the secrecy enhancement technique via artificial noise with protected zones of transmitter and receiver and investigated its gain by using stochastic geometry. For given arbitrary artificial noise power ratio, we first analyzed connection outage probability and secrecy outage probability for four different scenarios (separated, overlapped, included secrecy protected zones- type A, B) according to distance and size of protected zones of the transmitter and receiver. We then derive the secrecy transmission rate and find the optimal artificial noise power ratio to maximize it. Finally, with numerical examples, we investigate the effects of the system parameters such as size of protected zones of transmitter and receiver on the optimal artificial noise power ratio.

• Journal of the Korea Computer Industry Society
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• v.6 no.5
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• pp.783-790
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• 2005

In this paper, we have simulated a Symmetric Dual-gate Single-Si TFT which has three split floating n+ zones. This structure reduces the kink-effect drastically and improves the on-current. Due to the separated floating n+ zones, the transistor channel region is split into four zones with different lengths defined by a floating n+ region, This structure allows an effective reduction of the kink-effect depending on the length of two sub-channels. The on-current of the proposed dual-gate structure is 0.9mA while that of the conventional dual-gate structure is 0.5mA at a 12V drain voltage and a 7V gate voltage. This result shows a 80% enhancement in on-current. Moreover we observed the reduction of electric field in the channel region compared to conventional single-gate TFT and the reduction of the output conductance in the saturation region. In addition, we also confirmed the reduction of hole concentration in the channel region so that the kink-effect reduces effectively.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.11
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• pp.520-527
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• 2001

This paper suggests a new methodology of evolutionary computations - an Adaptive Evolutionary Algorithm (AEA) for solving the Economic Load Dispatch (ELD) problem which has piecewise quadratic cost functions and prohibited operating zones with many local minima. AEA uses a genetic algorithm (GA) and an evolution strategy (ES) in an adaptive manner in order to take merits of two different evolutionary computations: global search capability of GA and local search capability of ES. In the reproduction procedure, proportions of the population by GA and the population by ES are adaptively modulated according to the fitness. Case studies illustrate the superiority of the proposed methods to existing conventional methods in power generation cost and computation time. The results demonstrate that the AEA can be applied successfully in the solution of ELD with piecewise quadratic cost functions and prohibited operating zones