• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.18 no.1
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• pp.1-15
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• 2014

We have investigated optimal control strategies for prevention of ecstasy use. Ecstasy use has continued at raves and nightclubs in recent years and the reduction of ecstasy use has become one of the important issues in society. We apply optimal control theory to a model of the peer-driven dynamics of ecstasy use. Our goal is to minimize the ecstasy use class and the intervention cost. Optimal control is characterized in terms of the solution of optimality system, which is the state system coupled with the adjoint system and the optimality equations. The numerical simulations show the optimal prevention policies of ecstasy use in various scenarios.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.485-490
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• 2000

This paper describes the application of discretized continuum-type optimality criteria (DCOC) for minimum-cost design of the reinforced concrete frame structures consisting of beams and columns. The cost of construction as objective function which includes the costs of concrete, reinforced steel and formwork is minimized. The design constraints include limits on the maximum deflection at a prescribed node, bending and shear strengths in beams, uniaxial bending strength of columns according to design codes(CEB/FIP, 1990). In the first stage, only beams with uniform cross-sectional parameters per span are considered. But the steel ratio is allowed to vary freely. The cross-sectional parameters and steel ratio in each column are assumed to be uniform for practical reasons. Optimality criteria is given based on the well known Kuhn-Tucker necessary conditions, followed by an iterative procedure for designs when the design variables are the depth and the steel ratio. The versatility of the DCOC technique has been demonstrated by considering numerical examples which have one-bay four-storey frame.

• Proceedings of the Korean Society for Language and Information Conference
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• 2002.06a
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• pp.10-38
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• 2002

본고는 한국어 영형 대명사의 적절한 해석을 위해 개념적으로 전혀 새로운 이론을 제안한다. 일련의 다양한 제약들이 서로 연관되어 있음을 보인 후, 그러한 규칙의 다양성을 적절히 포착하기 위해 적절성 이론 (Optimality Theory)을 도입할 것을 제안하고, 그 토대 위에 다양한 제약들을 형식화한 후, 그 규칙들의 위계관계를 설정한다. 가장 우선순위를 갖는 제약으로 인접 요소간 어휘의미자질들이 일치해야 한다는 어휘의미제약(*Feature Mismatch)과 통사적 결속규칙을 의미론적으로 재해석한 결속원리 B(Principle B)를 선정한다. 그 다음 순위를 갖는 제약으로, 가능한 한 선행명사를 지칭하도록 요구하는 대용존중제약(DOAP: Don't Overlook Anaphoric Possibilities)과, 센터링 이론의 전이방식 개념을 도입하여 정의한 계속선호제약 (CONTINUE)을 제안한다

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.85-93
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• 2004

Electric vehicle body has to be subjected to uniform load and requires auxiliary equipment such as air pipe and electric wire pipe. Especially, the cross beam supports the weight of passenger and electrical equipments. This need to use adaptive design in initial design stage to gain economy through interchangeability between many kinds of components. This study performs the topology optimization by the concept of homogenization based on optimality criteria method which is efficient for the problem with a number of boundary condition and design variable. Therefore this provides the method to determine the optimum position and the shape of circular hole in the cross beam and then can achieve the weight minimization of electric vehicle body.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.183-190
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• 2001

Topology optimization. has been evolved into a very efficient conceptual design tool and has been utilized into design engineering processes in many industrial parts. In recent years, topology optimization has become the focus of structural optimization design and has been researched and widely applied both in academy and industry. Traditional topology optimization has been using homogenization method and optimality criteria method. Homogenization method provides relationship equation between structure which includes many holes and stiffness matrix in FEM. Optimality criteria method is used to update design variables while maintaining that volume fraction is uniform. Traditional topology optimization has advantage of good convergence but has disadvantage of too much convergency time and additive checkerboard prevention algorithm is needed. In one way to solve this problem, element remove method is presented. Then, it is applied to many examples. From the results, it is verified that the time of convergence is very improved and optimal designed results is obtained very similar to the results of traditional topology using 8 nodes per element.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.176-183
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• 1999

This paper describes the application of discretized continuum-type optimality criteria (DCOC) for the reinforced concrete continuous beams. The cost of construction as objective function which includes the costs of concrete, reinforced steel, formwork is minimized. The design constraints include limits on the maximum deflection in a given span, on bending and shear strengths, optimality criteria is given based on the well known Kuhn-Tucker necessary conditions, followed by an iterative procedure for designs when the design variables are the depth and the steel ratio. The self-weight of the beam is included in the equilibrium equation of the real system. Two numerical examples of reinforced concrete continuous beams with rectangular cross-section are solved to show the applicability and efficiency for the DCOC-based technique

• English Language & Literature Teaching
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• v.18 no.3
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• pp.121-134
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• 2012

The purpose of this study is to investigate the optimal conditions for designing tasks appropriate to the elementary classroom based on the correspondence with the national curriculum, integration among four skills (listening, speaking, reading, and writing), authenticity, and interactivity. For this study, two primary English teachers volunteered to participate in the case study conducted in the spring semester of the 2012 school year. Each class observed was composed of 29 and 30 sixth graders (12-year-old learners). Data were collected through classroom observation and lesson plans. Optimality theory was used to analyze data from the lessons. From the findings, the overall ranking of constraints is Curriculum ${\gg}$ Integration ${\gg}$ Authenticity ${\gg}$ Interactivity. It is also shown that for teacher 'L', the tasks such as 'guessing game', 'photo of me', and 'role play' were appropriate to help students ask questions and give reasons for their choices. As for teacher 'C', the tasks such as 'hand spans', 'transport survey', and 'picture telling' needed to be considered in order to help students understand and write comparative sentences.

• Asia pacific journal of information systems
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• v.1 no.1
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• pp.117-145
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• 1991

IS changeback is regarded as an offective way to control the usage of computers and communication systems which are very much limited resources and whose costs are very high, In this paper, the problem of combining the optimal chargeback system which guarantees the efficiency with the Rawls'(1971) concept of fairness. Primary conclusion of this paper is that if the value function which represents the contributions of IS user to the firm's profit is evidit and there is no uncertainty about this contribution information, optimality can be achived without any loss of fairness using full cost allocation pricing. But if there is no significant differences among contribution of each user and there is no significant differences among users because of the managerial arbitrariness, From this point of view contingent chargeback system with which manager can find the golden middle between optimality and fairness by adjusting the 'efficiency coefficient' according to his/her organizational characterisics and environments is proposed. A heuristic of finding the appropriate efficiency coefficient is also suggested.

• Language and Information
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• v.9 no.1
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• pp.51-68
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• 2005

This paper proposes an informational approach to the dative alternation in English following up on the Stochastic Optimality- Theoretic (OT) model by Bresnan and Nikitina (2003). While Bresnan and Nikitina's stochastic OT model resolves the crucial problem of 'gradience' unavoidably implicated in variation phenomena by applying the notion of probability to linguistic problems, it fails to account for the details of the unusually alternating examples, which normally would not alternate. More importantly, it fails to capture the focus effect involved in the alternation. This paper has worked out all the problematic examples by modifying the Bresnan and Nikitina model. This new account captures not only the unusual behavior of the less-alternating verbs and idioms but also the special focus effect of the common alternating verbs.

• Journal of the Korean Mathematical Society
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• v.46 no.5
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• pp.1007-1025
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• 2009

First-order least-squares method of a distributed optimal control problem for the incompressible Stokes equations is considered. An optimality system for the optimal solution are reformulated to the equivalent first-order system by introducing the vorticity and then the least-squares functional corresponding to the system is defined in terms of the sum of the squared $H^{-1}$ and $L^2$ norms of the residual equations of the system. Finite element approximations are studied and optimal error estimates are obtained. Resulting linear system of the optimality system is symmetric and positive definite. The V-cycle multigrid method is applied to the system to test computational efficiency.