• KIEE International Transactions on Power Engineering
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• v.3A no.4
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• pp.181-190
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• 2003

This paper presents the design of a fuzzy power system stabilizer (FPSS) using an adaptive evolutionary algorithm (AEA). AEA consists of genetic algorithm (GA) for a global search capability and evolution strategy (ES) for a local search in an adaptive manner when the present generation evolves into the next generation. AEA is used to optimize the membership functions and scaling factors of the FPSS. To evaluate the usefulness of the FPSS, we applied it to a single-machine infinite bus system (SIBS) and a power system simulator at the Korea Electrotechnology Research Institute. The FPSS displays better control performance than the conventional power system stabilizer (CPSS) for a three-phase fault in heavy load, which is used when tuning FPSS. To show the robustness of the FPSS, it is applied with disturbances such as change of mechanical torque and three-phase fault in nominal and heavy load, etc. The FPSS also demonstrates better robustness than the CPSS. Experimental results indicate that the FPSS has good system damping under various disturbances such as one-line to ground faults, line parameter changes, transformer tap changes, etc.

• Korean Journal of Biological Psychiatry
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• v.14 no.1
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• pp.14-20
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• 2007

Objectives : The diagnosis of depression is based on a highly variable set of symptoms. Therefore, depression should not be viewed as a single disease, but a heterogenous syndrome comprised of different pathophysiologies. There are several subtypes of depression which were already incorporated in DSM-IV. This article provides a systematic review of pharmacological treatments of two recognized subtypes of depression-dysthymic disorder and atypical depression. Methods : Systematic search of relevant literatures on dysthymic disorder and atypical depression was performed by proposed search strategy of the Clinical Research Center for Depression of Korean Health 21 R&D Project. All identified literatures were carefully reviewed and classified according to SIGN grading system and summarized in a narrative manner. Results : For the treatment of dysthymic disorder and atypical depression, selective serotonin reuptake inhibitors( SSRIs) and moclobemide have more evidence than the other antidepressants. SSRIs and moclobemide showed superior tolerability than tricyclic antidepressants. Conclusions : The authors proposed treatment recommendations for dysthymic disorder and atypical depression by the methods of evidence-based medicine(EBM). However, guideline developing methods of EBM also have several inevitable limitations. Therefore, in the absence of clear and significant differences in efficacy, the choice of medication must be individualized for a particular patient based on psychiatrist's own clinical decision.

• Journal of computational fluids engineering
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• v.11 no.2 s.33
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• pp.19-24
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• 2006

A research to evaluate the efficiency of design optimization was carried out for aerodynamic design optimization problem in distributed computing environment. The aerodynamic analyses which take most of computational work during design optimization were divided into several jobs and allocated to associated PC clients through network. This is not a parallel process based on domain decomposition in a single analysis rather than a simultaneous distributed-analyses using network-distributed computers. GBOM(gradient-based optimization method), SAO(Sequential Approximate Optimization) and RSM(Response Surface Method) were implemented to perform design optimization of transonic airfoils and evaluate their efficiencies. dimensional minimization followed by direction search involved in the GBOM was found an obstacle against improving efficiency of the design process in the present distributed computing system. The SAO was found fairly suitable for the distributed computing environment even it has a handicap of local search. The RSM is apparently the most efficient algorithm in the present distributed computing environment, but additional trial and error works needed to enhance the reliability of the approximation model deteriorate its efficiency from the practical point of view.

• Convergence Security Journal
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• v.15 no.1
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• pp.69-82
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• 2015

This dissertation introduce how to react against the cybercrime and analysis of malware detection. Also this dissertation emphasize the importance about efficient control of correspond process for the information security. Cybercrime and cyber breach are becoming increasingly intelligent and sophisticated. To correspond those crimes, the strategy of defense need change soft kill to hard kill. So this dissertation includes the study of weak point about OS, Application system. Also this dissertation suggest that API structure for handling and analyzing big data forensic.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.464-469
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• 1999

Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.311-321
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• 2007

For fast and robust face detection, this paper proposes an approach for face detection using fusion of heterogeneous template matching. First, we detect skin regions using a model of skin color which covers various illumination and races. After reducing a search space by region labelling and filtering, we apply template matching with skin color and edge to the detected regions. Finally, we detect a face by finding the best choice of template fusion. Experimental results show the proposed approach is more robust in skin color-like environments than with a single template matching and is fast by reducing a search space to face candidate regions. Also, using a global accumulator can reduce excessive space requirements of template matching.

• Journal of Computing Science and Engineering
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• v.2 no.4
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• pp.321-338
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• 2008

This paper presents a Modified Multiple Depth First Search algorithm for the exploration of the indoor environments occupied with obstacles in random distribution. The proposed algorithm was designed and implemented to employ one or a team of Khepera II mini robots for the exploration process. In case of multi-robots, the BlueCore2 External Bluetooth module was used to establish wireless networks with one master robot and one up to three slaves. Messages are sent and received via the module's Universal Asynchronous Receiver/Transmitter (UART) interface. Real exploration experiments were performed using locally developed teleworkbench with various autonomy features. In addition, computer simulation tool was also developed to simulate the exploration experiments with one master robot and one up to ten slaves. Computer simulations were in good agreement with the real experiments for the considered cases of one to one up to three networks. Results of the MMDFS for single robot exhibited 46% reduction in the needed number of steps for exploring environments with obstacles in comparison with other algorithms, namely the Ants algorithm and the original MDFS algorithm. This reduction reaches 71% whenever exploring open areas. Finally, results performed using multi-robots exhibited more reduction in the needed number of exploration steps.

• Management Science and Financial Engineering
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• v.18 no.1
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• pp.27-37
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• 2012

This paper is motivated by a military cargo-plane routing problem which is a pickup-and-delivery problem in which load splits and node revisits are allowed (PDPLS). Although this recent evolution of a VRP-model enhances the efficiency of routing, a solution method is more of a challenge since the node revisits entail closed walks in modeling vehicle routes. For such a case, even a compact IP-formulation is not available and an effective method had been lacking until Nowak et al. (2008b) proposed a heuristic based on a tabu search. Their method provides very reasonable solu-tions as demonstrated by the experiments not only in their paper (Nowak et al., 2008b) but also in ours. However, the computation time seems intensive especially for the class of problems with dynamic transportation requests, including the military cargo-plane routing problem. This paper proposes a more scalable algorithm hybridizing a tabu search for pricing subproblem paused as a single-vehicle routing problem, with a column generation approach based on Dantzig-Wolfe decomposition. As tested on a wide variety of instances, our algorithm produces, in average, a solution of an equiva-lent quality in 10~20% of the computation time of the previous method.

• The Journal of Internal Korean Medicine
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• v.36 no.2
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• pp.153-164
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• 2015

Objectives: The aim of this study was to collect and analyze studies on acupuncture therapies for treatment of voiding difficulty in stroke patients and to suggest methods of study for acupuncture therapies. Methods: Electronic searches were performed on search sites including NDSL, 국회도서관, RISS4U, DBPIA, KISS, KMBASE, KoreaMed, 한국전통지식포탈, OASIS, Pubmed, CNKI, using the search words ‘중풍’, ‘뇌졸중’, ‘stroke’, ‘배뇨장애’, ‘voiding’, ‘urinary’, ‘incontinence’, ‘retention’, ‘ ’, ‘침치료’, and ‘acupuncture’ as single or combined keywords, from January 1990 to August 2013 with language limitation, Korean, English, Chinese. Also, quality of the studies were evaluated using Jadad score. Results: The searches identified 16 studies for selection and analysis. In the present study, voiding difficulty includes urinary incontinence and urinary retention. The acupuncture points CV4, SP6, and CV3 were the most frequently used. Treatments were most frequently applied daily. The times and terms of acupuncture treatment, were most frequently 30 minutes per treatment for 4 weeks Conclusions: The acupuncture therapies were effective in the treatment of voiding difficulty in stroke patients, but the study of acupuncture therapy as a treatment for this issue in stroke patients needs to be standardized and high-quality study models should be introduced.

• Journal of Integrative Natural Science
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• v.3 no.1
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• pp.49-53
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• 2010

Molecular docking is a critical event which mostly forms Van der waals complex in molecular recognition. Since the majority of developed drugs are small molecules, docking them into proteins has been a prime concern in drug discovery community. Since the binding pose space is too vast to cover completely, many search algorithms such as genetic algorithm, Monte Carlo, simulated annealing, distance geometry have been developed. Proper evaluation of the quality of binding is an essential problem. Scoring functions derived from force fields handle the ligand binding prediction with the use of potential energies and sometimes in combination with solvation and entropy contributions. Knowledge-based scoring functions are based on atom pair potentials derived from structural databases. Forces and potentials are collected from known protein-ligand complexes to get a score for their binding affinities (e.g. PME). Empirical scoring functions are derived from training sets of protein-ligand complexes with determined affinity data. Because non of any single scoring function performs generally better than others, some other approaches have been tried. Although numerous scoring functions have been developed to locate the correct binding poses, it still remains a major hurdle to derive an accurate scoring function for general targets. Recently, consensus scoring functions and target specific scoring functions have been studied to overcome the current limitations.