• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.232-242
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• 2015

Analytical study of surface recombination at the $Si/SiO_2$ interface is carried out in order to set the optimum surface conditions that result in minimum dark base current and maximum open circuit voltage in silicon solar cells. Recombination centers are assumed to form a continuum rather than to be at a single energy level in the energy gap. It is shown that the presence of a hump in the dark I-V characteristics of high efficiency PERL cells is due to the dark current transition from a high surface recombination regime at low voltage to a low surface recombination regime at high voltage. Successful fitting of reported dark I-V characteristics of a typical PERL cell is obtained with several possible combinations of surface parameters including equal electron and hole capture cross sections.

• Korean Institute of Interior Design Journal
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• no.23
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• pp.139-147
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• 2000

The cultural identity of design is very critical in the modern society which is called the society of complex culture and multi-culture. In addition, adopting a traditional lattice-like pattern as a composition element of interior space is an effective way in the context of adding a traditional touch to the modern interior space. Meanwhile, in the process of applying Korean traditional lattices to modern interior space, some problems occurred: it has not been properly embodied; or it has been mistaken for those of China and Japan sharing similar culture with Korea. Thus, this study is designed to have precise knowledge of Korea, Chinese and Japanese traditional lattices. Besides, typical patterns of each nation's lattices are comparatively analyzed from the geometrical viewpoint, in a bid to pave the way for th modernization of traditional lattices. In particular, standards are set and proposed to identify different nations's lattices mainly focusing on grid type lattices which are often used and confusing.

• Korean Institute of Interior Design Journal
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• no.41
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• pp.190-197
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• 2003

This study is based on the Importance of home office in domestic environment in Korea. In recent years, the distribution of network environment at home has been changed rapidly Each family member uses home office for various purpose. The home office in domestic living environment become a part of common use for all family member. The purpose of this study is to set the framework of design direction in terms of system furniture for home office within the limitation of current standard space at home such as typical apartment - 30 pyeong, 40 pyeong. The first step of study is to understand user space and user needs through the user survey. The second step is to find the right location and plan of home office in domestic environment. The last is to suggest the integral system furniture and elements that fits to the various situations of location according to the space and user type.

• Structural Engineering and Mechanics
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• v.30 no.5
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• pp.559-576
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• 2008

Having established the initial geometry and cable force of a typical three span suspension bridge under permanent load, the additional maximum response of the cable and the stiffening girder due to live load are determined, by means of an analytic procedure, considering the girder first hinged at its ends and then continuous through the main towers. The problem of interaction between the cable and the stiffening girder is examined taking under due consideration the second order effects, whereby, through the analogy to a fictitious tensioned beam under transverse load, a closed -form solution is achieved by means of a simple quadratic equation. It is found that the behavior of the whole system is governed by five simple dimensionless parameters which enable a quick determination of all the relevant design magnitudes of the bridge. Moreover, by introducing these parameters, a set of diagrams is presented, which enable the estimation of the influence of the geometric and loading data on the response and permit its immediate evaluation for preliminary design purposes.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.4
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• pp.37-50
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• 2012

The existing DEA models have been devoted to evaluate relative efficiency of DMUs based on multiple input and output factors of a same period. However, a certain kind of lead time can be required to produce outputs using inputs in an organization. R&D evaluation is a typical area with this kinds of time lag. Thus, the purpose of this paper is to develop a new DEA model to deal with time lag effect in performance evaluation. The proposed model is to find relative efficiency of each DMU for each period considering the time lag effect. A case example using a real data set is also given to show the usage or implication of the suggested model. The results are compared with the ones of the CCR model and the multi-periods input model.

• Bioinformatics and Biosystems
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• v.2 no.2
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• pp.52-57
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• 2007

The computational discovery of transcription factor binding site is one of the important tools in the genetic and genomic analysis. Rough prediction of gene regulation network and finding possible co-regulated genes are typical applications of the technique. Countless motif-discovery algorithms have been proposed for the past years. However, there is no dominant algorithm yet. Each algorithm does not give enough accuracy without extensive information. In this paper, we explore the possibility of combining multiple algorithms for the one integrated result in order to improve the performance and the convenience of researchers. Moreover, we apply new high order information that is reorganized from the set of basis predictions to the final prediction.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.3
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• pp.210-217
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• 2010

This paper presents integrated path planning and collision avoidance for an omni-directional mobile robot. In this scheme, the autonomous mobile robot finds the shortest path by the descendent gradient of a navigation function to reach a goal. In doing so, the robot based on the proposed approach attempts to overcome some of the typical problems that may pose to the conventional robot navigation. In particular, this paper presents a set of analysis for an omni-directional mobile robot to avoid trapped situations for two representative scenarios: 1) Ushaped deep narrow obstacle and 2) narrow passage problem between two obstacles. The proposed navigation scheme eliminates the nonfeasible area for the two cases by the help of the descendent gradient of the navigation function and the characteristics of an omni-directional mobile robot. The simulation results show that the proposed navigation scheme can effectively construct a path-planning system in the capability of reaching a goal and avoiding obstacles despite possible trapped situations under uncertain world knowledge.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.1
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• pp.53-73
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• 2002

The launch of a new business is crucial to the future growth and profitability of a company. A new business project typically requires a large amount of resources while it has a high possibility of failure. The evaluation of new business opportunities is therefore quite a critical decision-making to companies. This evaluation includes screening of a large number of criteria at a time which often makes desision-making very complicated. Management should evaluate the business alternatives in a sound and consistent manner that is hard to achieve because the new business evaluation is a typical semi/unstructured decision-making problem. The difficulty in such an evaluation will increase if it is required for management to consider both quantitative and qualitative criteria simultaneously. Under these circumstances, this study has proposed a decision-making framework that utilizes analytical hierarchy process(AHP). This study has identified a set of criteria essential to the new business evaluation and suggested a systematic framework for it. Both qualitative and quantitative evaluations are incorporated into the single framework in this study.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.1
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• pp.17-40
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• 1994

The objectives of this paper are to apply fuzzy cognitive map (FCM)- related techniques to (1) extract causal knowledge from a specific problem-domain and (2) perform a series of causal analysis in complicated decision making area. We propose a set operation-based augmentation (SOBA) algorithm to combine multiple FCMs developed by multiple experts. Based on the SOBA knowledge acquisition algorithm, we can obtain a causal knowledge base fairly representing multiple experts' knowledge about a problem domain. The causal knowledge base built by SOBA algorithm can be described as a matrix form, guaranteeing mathematically compact operation compared with a production (if-then) knowledge base. We applied out method to stock market analysis problem whichis a typical of highly unstructured problems in OR/MS fields.

• Communications for Statistical Applications and Methods
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• v.16 no.6
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• pp.959-969
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• 2009

Decision tree is a typical tool for data classification. This tool is implemented in DAVIS (Huh and Song, 2002). All the visualization tools and statistical clustering tools implemented in DAVIS can communicate with the decision tree. This paper presents methods to apply data visualization techniques to the decision tree using a real data set.