• Journal of the Korean Mathematical Society
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• v.57 no.5
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• pp.1267-1286
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• 2020

We pay attention to a coupled problem by a penalty term which is induced from non-overlapping domain decomposition methods based on augmented Lagrangian methodology. The coupled problem is composed by two parts mainly; one is a problem associated with local problems in non-overlapping subdomains and the other is a coupled part over all subdomains due to the penalty term. For the speedup of iterative solvers for the coupled problem, we propose two different types of preconditioners: a block-diagonal preconditioner and an additive Schwarz preconditioner as overlapping domain decomposition methods. We analyze the coupled problem and the preconditioned problems in terms of their condition numbers. Finally we present numerical results which show the performance of the proposed methods.

• Structural Engineering and Mechanics
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• v.12 no.1
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• pp.101-118
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• 2001

The reliable prediction of elastic vibrations of wetted complex structures, as ships, tanks, offshore structures, propulsion components etc. represent a theoretical and numerical demanding task due to fluid-structure interaction. The paper presented is addressed to the vibration analysis by a combined FE-BE-procedure based on the added mass concept utilizing a direct boundary integral formulation of the potential fluid problem in interior and exterior domains. The discretization is realized by boundary element collocation method using conventional as well as infinite boundary element formulation with analytical integration scheme. Particular attention is devoted to modelling of interior problems with both several separate or communicating fluid domains as well as thin-walled structures wetted on both sides. To deal with this specific kind of interaction problems so-called "virtual" boundary elements in areas of cut outs are placed to satisfy the kinematical conditions in partial connected fluid domains existing in realistic tank systems. Numerical results of various theoretical and practical examples demonstrate the performance of the BE-methodology presented.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.876-879
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• 1996

The vibration of an attractive magnetic levitation(Maglev) vehicle transportation system is caused by the irregularity of the guideway track and the performance of the suspensions of the Maglev system. It is essential for us to give attention to the secondary suspension of the vehicle system as it determines the ride quality. In order to improve the ride quality and running stability, active secondary suspensions have been developed and applied to the vibration problems. This paper analyzes the performance of the active secondary suspension which is applied to an attractive magnetic levitation vehicle system running on a rough track. The dynamics of the suspension system and the optimal control problems are studied. According to the transient and frequency response analyses to the track disturbance, the ride quality of an attractive Maglev vehicle has been improved by applying the designed LQR active controller, and it has been confirmed that this improvement was also influenced by the configuration of the system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.988-991
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• 1996

The purpose of this thesis is to develop methods of designing robust LQR/LQG controllers for time-varying systems with real parametric uncertainties. Controller design that meet desired performance and robust specifications is one of the most important unsolved problems in control engineering. We propose a new framework to solve these problems using Linear Matrix Inequalities (LMls) which have gained much attention in recent years, for their computational tractability and usefulness in control engineering. In Robust LQR case, the formulation of LMI based problem is straightforward and we can say that the obtained solution is the global optimum because the transformed problem is convex. In Robust LQG case, the formulation is difficult because the objective function and constraint are all nonlinear, therefore these are not treatable directly by LMI. We propose a sequential solving method which consist of a block-diagonal approach and a full-block approach. Block-diagonal approach gives a conservative solution and it is used as a initial guess for a full-block approach. In full-block approach two LMIs are solved sequentially in iterative manner. Because this algorithm must be solved iteratively, the obtained solution may not be globally optimal.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.691-692
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• 2001

Until tile 1980s, the disposal of End of Life Vehicles (ELV) was considered unproblematic in Japan, Korea. and Taiwan. But in recent years, as environmental problems have attracted increasing attention. the processing oi ELV has become one of the most critical environmental issues. Discarded ELV represent a serious source of waste generation and pollution. In this paper, I will analyze the ELV problem from three view points: 1) ELV abandoned in the environment; 2) Significant environmental hazards caused by dismantling operations; and 3) Problems of how to deal with Automobile Shredder Residue (ASR).

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.455-460
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• 2010

Recent increases in the road and rail infrastructure, but the urban traffic problems such as accidents, congestion are increasing. The reason is that the high cost and lack of accessibility of railway transportation, the low quality of road services, and efficient transport links, etc.. The developments of a variety of policy and technical means are being performed to solve these problems. Among them, the Bimodal Tram which is combined low-cost of bus and high service quality of railway transportation is attracting attention. In this paper, the development status of technology and efficient utilization of operational and infrastructure elements for the operational efficiency, safety and passenger comfort of Bimodal Tram is studied.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1913-1919
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• 2007

Substantive provisions of the concept of an estimation and safety of complex technical systems are envisaged. New problems are assume orientation to use of the formalized methods of an estimation of residual resources of reliability of objects, and also development of other methodological base in creation of complex technical systems that is connected with detailed elaboration of attention to a safety at all stages of creation of systems: from designing until operation. In this connection existing large objects should be provided by the developed systems of engineering monitoring and diagnostics.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.2 no.2
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• pp.111-114
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• 1979

Human Engineering is the new science that studies tile function and the characteristic of human. It is purpose to design machine equipments for him to be able to manipulate those, exactly, safely and easily. This study will introduce that new science in traffic problems and will be done as follows. 1. The Presentation of Problems: 2. Human Engineering and Accurrence process of traffic accidents. 3. Human Engineering and aptitude analysis 4. Conclusion In this paper, driver is not the man who drives a car, is the man who is able to adapt himself to road, and traffic environment. There is a limitation in Human faculty, especially, in the power of attention. Therefore, this paper will be studied to show that it is seeking the ability needed by traffic analysis as well as getting ability of aptitude to attribute to prevention of traffic accidents.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.sup1
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• pp.118-126
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• 2009

The incidence of childhood obesity has increased dramatically. Childhood obesity is an increasing health problem because of its strong associations with chronic health problems in children and adults. These health problems significantly contribute to the development of common chronic diseases in later life, including hypertension, type2 diabetes, hyperinsulinemia, coronary heart disease, and other psychological disorders. So it is an important issue to prevent and treat obesity during childhood and adolescent. Diet and exercise are the cornerstones of treatment for obesity and related complications. For obese children, some clinical trials have shown improvement with diet, exercise, and /or behavioral interventions. Promising interventions for high-risk individuals, such as bariatric surgery and novel pharmacological agents, also require rigorous assessment with attention to long-term patient important outcomes. There are various pharmacological approaches to the treatment of obesity in the adolescent population some of which have FDA approval. In the article we discuss pharmacological approaches to guide the treatment of obesity in the pediatric population, including risks of treatment, monitoring of potential side effects.

• Korean Journal of Child Studies
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• v.24 no.6
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• pp.1-14
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• 2003

In contrast with Zelazo and Frye (1997) who argued that preschool children lack the conscious representation and executive functioning needed to solve problems based on conflicting rules, Bilaystok (1999) identified analysis(representation) and control(selective attention) as components of language processing and has shown that control develops earlier in bilingual than in monolingual children. This study investigated the effects of bilingualism on children's cognitive ability and language development by comparing Korean- Chinese bilingual with Chinese monolingual children in Yanji. Sixty children 3 to 5 years of age in each of the bilingual and the monolingual groups in Yanji, China participated in ths study. Results showed that bilingual were more advanced than monolingual children in solving problems requiring a high level of control, confirming Bialystok's(1999) results.