• Bulletin of the Korean Mathematical Society
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• v.26 no.2
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• pp.127-134
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• 1989

This paper proposes a deformation method for solving practical nonlinear programming problems. Utilizing the nonlinear parametric programming technique with Quasi-Newton method [6,7], the method solves the problem by imbedding it into a suitable one-parameter family of problems. The approach discussed in this paper was originally developed with the aim of solving a system of structural optimization problems with frequently appears in various kind of engineering design. It is assumed that we have to solve more than one structural problem of the same type. It an optimal solution of one of these problems is available, then the optimal solutions of thel other problems can be easily obtained by using this known problem and its optimal solution as the initial problem of our parametric method. The method of nonlinear programming does not generally converge to the optimal solution from an arbitrary starting point if the initial estimate is not sufficiently close to the solution. On the other hand, the deformation method described in this paper is advantageous in that it is likely to obtain the optimal solution every if the initial point is not necessarily in a small neighborhood of the solution. the Jacobian matrix of the iteration formula has the special structural features [2, 3]. Sectioon 2 describes nonlinear parametric programming problem imbeded into a one-parameter family of problems. In Section 3 the iteration formulas for one-parameter are developed. Section 4 discusses parametric approach for Quasi-Newton method and gives algorithm for finding the optimal solution.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.107-116
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• 2006

Recently, it has been important not only to evaluate environmental effects but also to assess cumulative and comprehensive effects by the development projects. This paper concentrates on temporal and spatial cumulative impacts on Suji district in Yongin, Gyunggi-do. This paper adopted two methods to assess the cumulative impacts. First, it assesses the temporal change of forest patch size and land cover according to the patch size. Second, it compares housing development zones with the neighborhood. The result of the research appears that the damage is very serious, especially in small forest. The Forest area is changed to farm land, most of them become to built-up area later. In addition, it is assessed that the secondary housing development projects did more harm than the initial one. By assessing the cumulative impacts on Suji district, this research suggests to minimize two kinds of solutions : comprehensive environmental assessments in regional unit and regulation on total forest quantity.

• Journal of Korea Multimedia Society
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• v.13 no.9
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• pp.1329-1336
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• 2010

Cellular Automata is a discrete dynamical system which natural phenomena may be specified completely in terms of local relation, can increase and decrease the difference of luminance locally according to transition rule by keeping the characteristic of target image. In this paper, we propose a noise reduction method by keeping the characteristic using transition rule of Cellular Automata, also we propose methods of effective transition rule, the selection of parameters, the selection of number of neighborhood pixels. For uniform distribution noise, Gaussian noise, impulse noise, we do an experiment on adaptive state using different mathematical operations and compare its results. It was confirmed that the proposed transition rule is based on fast convergence speed and has stabile results.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.221-226
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• 2006

An Ad hoc network, differently from wired networks, is a self organized network of mobile nodes in wireless environments. In this kind of routing and operation environments. link breaks occur frequently. Knowing positions of nodes may prevent or recover this type of phenomenon. Typically, GPS is used to detect position of nodes but high cost and complexity of construction limit applications. In this paper, we propose and design a method of construction nodes' position map using only information of all nodes without GPS. The proposed method complements and overcomes previous system with software solutions. Hence, construction and operation are simple, and can decrease cost of construction expenses.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.1
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• pp.9-18
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• 2015

The purpose of this study is to analyze the usage of eco-friendly elements in Korean traditional architecture to evaluate Hanok(Unjoru and Jinwondang) according to Green Building Certification Criteria(G-SEED). The results of this study were as follows; Unjoru and Jinwondang was not enough to obtain certification points. From Site usage and Traffic category, Jinwondang gets more points than Unjoru. It's because Jinwondang is located in downtown Seoul, so it gets more points of traffic and neighborhood facility. From Energy and Environmental Pollution category, Jinwondang gets more points of energy performance than Unjoru, too. It's because Jinwondang secured insulation performance of wall and windows using insulator and glass. From Resources category, Unjoru gets more points than Jinwondang. It shows that modern Hanok was limited using natural resources. From Ecological Environments category, Jinwondang is located urban area, it's difficult to secure the open space, so Unjoru gets more points than Jinwondang. If Modern Honok installs a system that can getting point and secure insulation performance, it will be certificated according to G-SEED.

• Journal of the Korean housing association
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• v.23 no.5
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• pp.87-94
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• 2012

The primary purposes of this study are to suggest a medium-sized regeneration project which includes the excluded small sites near existing regeneration site, to identify urban improvement type which fits local conditions, and to suggest proper regeneration strategies for the improvement type. Main findings of this study are follows. First, the size of the living environment improvement project in urban area should be larger than 3ha and government's incentives are required for parcel merges to make the medium-size project site. Second, independent type of urban regeneration project should consider local characteristics while center-spread type of urban regeneration project should build a center by providing neighborhood facilities and proper housings. Third, urban regeneration project should be able to utilize local assets, such as cultural heritages, natural landscapes, transportation facilities. Fourth, standards for public support should be prepared to improve local competitiveness. Last, further studies are required for urban regeneration system improvement.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.599-604
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• 2000

In order to study unsteady aerodynamic loads on high speed trains passing by each other at the speed of 350km/h, three-dimensional flow fields around trains during the crossing event are numerically simulated using the three-dimensional Euler equations. The Roe's FDS with MUSCL interpolation is employed to simulate wave phenomena properly. An efficient moving grid system based on domain decomposition techniques is developed to analyze the unsteady flow field induced by the restricted motion of a train on a rail. The numerical simulations of the trains passing by on the double-track are carried out to study the effect of the train nose-shape, the train length and the existence of tunnel when the crossing event occur. Unsteady aerodynamic loads side force and drag force-acting on the train during the crossing are numerically predicted and anlayzed. It is found that the strength of the side force mainly depends on the nose-shape, and that of drag force on tunnel existence. And it is observed that the push-pull like impulsive force successively acts on each car and acts in different directions between the neighborhood cars. The maximum change of the impulsive force reaches about 3 tons. These aerodynamic force data are absolutely necessary for the evaluation of the stability of the high speed multi-car train. The results also indicate the effectiveness of the present numerical method for the simulation of unsteady flow field induced by the bodies in the relative motion.

• Journal of Information Technology Services
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• v.7 no.3
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• pp.71-85
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• 2008

The rapid growth of blog has caused information overload where bloggers in the virtual community space are no longer able to effectively choose the blogs they are exposed to. Recommender systems have been widely advocated as a way of coping with the problem of information overload in e-business environment. Collaborative Filtering (CF) is the most successful recommendation method to date and used in many of the recommender systems. In this research, we propose a CF-based recommender system for bloggers to find their similar bloggers or preferable virtual community without burdensome search effort. For such a purpose, we apply the "Interest Value" to CF recommender systems. The Interest Value is the quantity value about users' transaction data in virtual community, and can measure the opinion of users accurately. Based on the Interest Value, the neighborhood group is generated, and virtual community list is recommended using the Community Likeness Score (ClS). Our experimental results upon real data of Korean Blog site show that the methodology is capable of dealing with the information overload issue in virtual community space. And Interest Value is proved to have the potential to meet the challenge of recommendation methodologies in virtual community space.

• Journal of KIISE
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• v.42 no.11
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• pp.1380-1385
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• 2015

Collaborative filtering is one of the most successfully used methods for recommender systems and has been utilized in various areas such as books and music. The key point of this method is selecting the most proper recommenders, for which various similarity measures have been studied. To improve recommendation performance, this study analyzes problems of existing recommender selection methods based on similarity and presents a method of dynamically determining recommenders based on the rate of co-rated items as well as similarity. Examination of performance with varying thresholds through experiments revealed that the proposed method yielded greatly improved results in both prediction and recommendation qualities, and that in particular, this method showed performance improvements with only a few recommenders satisfying the given thresholds.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.327-327
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• 2011

A nonthermal bioplasma source was developed for application to human liquid fluids by making use of nano-size tungsten tips. Characteristics of the plasma source are investigated. Here we have used the AC voltage system. The bioplasma source generated by a tungsten tip with quartz tube and ground electrode is a low-temperature plasma without making any noticeable damage to cells at a low power operation. The breakdown voltage and current signals are measured by high voltage probe (Tektronix P6015A) and current probe (P6021). Variation of breakdown temperature near the tip electrode is larger than that in the neighborhood of ground electrode. Bubble formation during discharge has been recorded and investigated by using the high speed camera. The existence and behavior of hydroxyl and superoxide radicals are detected and measured by spectrometers. The electrical and optical properties of breakdown characteristics are also investigated.