• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1005-1010
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• 1998

실험계획법을 이용하여 유리분말의 소결시 그 기공량에 영향을 미치는 각종 소결조건의 영향을 정량적으로 조사하였다. 본 실험범위내에서 결합제 유리의 총기공량, 개기공량 그미고 폐기공량은 모두 소결온도에 의해 가장 큰 영향을 받고 그 다음으로 소결온도에서의 유지시간에 의해 영향을 받으며 승온속도의 경우 그 영향이 상대적으로 미미함을 확인할 수 있었다. 이러한 결과들로부터 실제공정에 있어 승온속도보다는 다른 소결인자, 특히 소결온도를 조절하는 것이 결합제 유리의 기공량 조절에 가장 중요하리라 판단되며 실험계획법을 이용함으로써 보다 정확한 공전조건을 모색할 수 있었다.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.393-405
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• 2000

Box and Draper( 19(5) listed some properties of a design that should be considered in design selection. But it is impossible that one design criterion from optimal experimental design theory reflects many potential objectives of an experiment, because the theory was originally based on the underlying model and its strict assumption about the error structure. Therefore, when it is neces::;ary to implement multi-objective experimental design. it is common practice to balance out the several optimal design criteria so that each design criterion involved benefits in terms of its relative "high" efficiency. In this study, we proposed several composite design criteria taking the case of heteroscedastic model. WVhen the heteroscedasticity is present in the model. the well known equivalence theorem between 1)- and C-optimality no longer exists and furthermore their design characteristics are sometimes drastically different. We introduced three different design criteria for this purpose: constrained design, combined design, and minimax design criteria. While the first two methods do reflect the prior belief of experimenter, the last one does not take it into account. which is sometimes desirable. Also we extended this method to the case when there are uncertainties concerning the error structure in the model. A simple algorithm and concluslOn follow.On follow.

• The Korean Journal of Applied Statistics
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• v.27 no.6
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• pp.1029-1038
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• 2014

Bayesian experimental design is a useful concept in applied statistics for the design of efficient experiments especially if prior knowledge in the experiment is available. However, a theoretical or numerical approach is not simple to implement. We review the concept of a Bayesian experiment approach for linear and nonlinear statistical models. We investigate relationships between prior knowledge and optimal design to identify Bayesian experimental design process characteristics. A balanced design is important if we do not have prior knowledge; however, prior knowledge is important in design and expert opinions should reflect an efficient analysis. Care should be taken if we set a small sample size with a vague improper prior since both Bayesian design and non-Bayesian design provide incorrect solutions.

• The Korean Journal of Applied Statistics
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• v.30 no.2
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• pp.291-299
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• 2017

Mack and Skillings (1980) proposed nonparametric procedures in a randomized block design with replications as general alternatives. This method is used to find the difference in the treatment effect; however, it can cause a loss of inter block information using the ranking in each block. In this paper, we proposed new nonparametric procedures in a randomized block design with replications using an aligned method proposed by Hodges and Lehmann (1962) that used information of blocks and based on the joint placement suggest by Chung and Kim (2008). We also compared the power of the test of the proposed procedures and established a method through Monte Carlo simulation.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.764-765
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• 2015

전자기 시스템에서 발생하는 손실의 대부분은 열에너지로 발생되며 전력기기와 같은 대용량 시스템의 경우 금속도체부의 국부적 온도상승은 그 자체로도 시스템의 성능을 저하시키거나 심각한 경우 사고를 유발시키며 수명을 단축시킨다. 이를 개선하기 위한 방안으로 Hot-spot 부근에 자기실드를 삽입하여 누설자속을 차폐시키는 방법도 고려되고 있다. 본 논문에서는 이러한 열유동 결합된 자기차폐 문제의 최적설계를 실험계획법을 이용하여 수행하였다.

• Elastomers and Composites
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• v.44 no.4
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• pp.366-372
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• 2009

The present study covers the optimal design for a lens module in a mobile phone camera by using the design of experiments (DOE) and finite element (FE) analysis. FE analyses are performed to investigate the effect of design parameters on the amount of torque required to assemble a barrel and a housing part. The DOE approach is then performed to optimize the design parameters in order to maintain an appropriate torque with less variations.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.27-35
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• 2009

Integer programming is a very effective technique for searching optimal solution of combinatorial optimization problems. However, its applicability is limited to linear models. In this paper, I propose an effective method for solving a nonlinear optimization problem by integrating the powerful search performance of integer programming and the flexibility of neighborhood search algorithms. In the first phase, integer programming is executed with subproblem which can be represented as a linear form from the given problem. In the second phase, a neighborhood search algorithm is executed with the whole problem by taking the result of the first phase as the initial solution. Through the experimental results using a nonlinear maximal covering problem, I confirmed that such a simple integration method can produce far better solutions than a neighborhood search algorithm alone. It is estimated that the success is primarily due to the powerful performance of integer programming.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.59-60
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• 2008

산화실리콘 박막은 생체적합성, 폴리머 필름의 gas barrier, 저유전율, 환경차단 보호막 등 다양한 특성을 갖고 있어 연구개발이 활발하게 이루어지고 있다. 본 연구는 저진공 화학기상증착법 (LPCVD)를 이용하여 산화실리콘 박막을 제작하였다. 실리콘 박막을 위한 전구체는 환경 친화적이며 상온에서 비교적 높은 증발점을 갖는 hexamethyldisiloxane (HMDSO)을 이용하였으며, 이때 기판은 실리콘을 이용하였다. LPCVD의 공정변수는 전구체 공급량(진공도)과 RF power를 중심으로하여 Taguchi 실험계획법에 따라 박막을 제작하였다. 또한, 실험계획법에 의해 최적 전구체 공급량과 RF power를 결정하고 산소분압의 변화에 따른 산화실리콘 박막을 제작하였다. 산화실리콘 박막은 표면특성 및 화학적 결합상태를 수접촉각, SEM, AFM, FTIR 등을 이용하여 관찰하고 분석하였다.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.13-27
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• 2012

Integer programming-based local search(IPbLS) is a kind of local search based on simple hill-climbing search and adopts integer programming for neighbor generation unlike general local search. According to an existing research [1], IPbLS is known as an effective method for the multidimensional knapsack problem(MKP) which has received wide attention in operations research and artificial intelligence area. However, the existing research has a shortcoming that it verified the superiority of IPbLS targeting only largest-scale problems among MKP test problems in the OR-Library. In this paper, I verify the superiority of IPbLS more objectively by applying it to other problems. In addition, unlike the existing IPbLS that combines simple hill-climbing search and integer programming, I propose methods combining other local search algorithms like hill-climbing search, tabu search, simulated annealing with integer programming. Through the experimental results, I confirmed that IPbLS shows comparable or better performance than the best known heuristic search also for mid or small-scale MKP test problems.

• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.95-103
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• 2013

Nonparametric procedure in randomized block design (RBD) was proposed by Friedman (1937) for general alternatives. Also Page (1963) suggested the test for ordered alternatives in RBD. In this paper, we proposed the new nonparametric method in randomized block design using aligned method suggested by Hodges and Lehmann (1962) and the joint placement described in Chung and Kim (2007). Also, Monte Carlo simulation study was adapted to compare the power of the proposed procedure with those of previous procedure.