• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.486-486
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• 2006

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2001.08a
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• pp.103-127
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• 2001

Gene expression studies require statistical experimental designs and validation before laboratory confirmation. Various clustering approaches, such as hierarchical, Kmeans, SOM are commonly used for unsupervised learning in gene expression data. Several classification methods, such as gene voting, SVM, or discriminant analysis are used for supervised lerning, where well-defined response classification is possible. Estimating gene-condition interaction effects require advanced, computationally-intensive statistical approaches.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.2
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• pp.179-189
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• 2003

Gate poly-silicon critical dimension is a prime characteristic of a metal-oxide-semiconductor field effect transistor. It is important to achieve the uniformity of gate poly-silicon critical dimension in order that a semiconductor device has acceptable electrical test characteristics as well as a semiconductor wafer fabrication process has a competitive net-die-per-wafer yield. However, on gate poly-silicon critical dimension, the complexity associated with a semiconductor wafer fabrication process entails hierarchical variance components according to run-to-run, wafer-to-wafer and even die-to-die production unit changes. Specifically, estimates of the hierarchical variance components are required not only for disclosing dominant sources of the variation but also for testing the wafer-level uniformity. In this paper, two experimental designs, a two-stage nested design and a randomized complete block design are considered in order to estimate the hierarchical variance components. Since gate poly-silicon critical dimensions are collected from fixed die positions within wafers, a factor representing die positions can be regarded as fixed in linear statistical models for the designs. In this context, the two-stage nested design also checks the wafer-level uniformity taking all sampled runs into account. In more detail, using variance estimates derived from randomized complete block designs, Duncan's multiple range test examines the wafer-level uniformity for each run. Consequently, a framework presented in this study could provide guidelines to practitioners on estimating the hierarchical variance components and testing the wafer-level uniformity in parallel for any characteristics concerned in semiconductor wafer fabrication processes. Statistical analysis is illustrated for an experimental dataset from a real pilot semiconductor wafer fabrication process.

• Journal of the Korean Society for Library and Information Science
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• v.25
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• pp.325-341
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• 1993

The experimental method, when carried out properly, is the most powerful way of seeking answers to research questions. The purpose of this study is to provide practical and theoretical insights as well as to discuss technical skills needed to design and implement the experimental research in library and information science. The levels of empirical research methods, the logic and types of the experimental designs, the application status of the experimental methods through content analysis of the published papers, and strategies to plan the research and to collect and analyze data are examined. This study also brings suggestions how experimental research can be made more meaningful and puts emphasis on the need of the research method education in library and information science field.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.580-593
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• 1998

The small composite design for second order response surface might be appropriate when experimentation is expensive, difficult, or time-consuming, especially when an independent estimate of experimental error is available. It is important that the small composite designs for response surface analysis would be rotatable and slope-rotatable. Therefore the small composite designs are studied from the viewpoint of rotatability and slope-rotatability, and the optimal values of a(the distance of axial points from the center) are investigated as k(the number of independent variables) and $n_0$(the number of center points) are changed.

• Child Health Nursing Research
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• v.23 no.3
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• pp.300-311
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• 2017

Purpose: There are many forest and outdoor programs being offered but systematic reviews of effects are lacking. This study was done to identify content, format, and strategies of forest therapy programs for elementary school students. Methods: Literature search using keywords in English and Korean was performed using 6 electronic databases in December 2016. Search participants were elementary school students and interventions conducted in the forest. Seventeen forest therapy studies were selected for evaluation. Risk of Bias Assessment tool for non-randomized study was used for quality assessment. Results: All studies were quasi-experimental designs. Forest therapy programs included various activities in forests such as experience of five senses, meditation in the forest, walking in the forest, ecological play, observation of animals and insects. All studies used psychosocial health variables and forest healing programs had positive effects on sociality, depression, anxiety, self-esteem, stress, aggression, anger, and school adjustment. Limitations of these studies were vague reporting of the study, lack of ethical review and rigorous research designs. Conclusion: Forest therapy for elementary school child can be an effective way to improve psychosocial health. Future studies with rigorous study designs are needed to assess long-term effects of forest therapy on physical and psychosocial health.

• International Journal of Fluid Machinery and Systems
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• v.3 no.2
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• pp.150-159
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• 2010

Laidback fan shaped film-cooling hole is formulated numerically and optimized with the help of three-dimensional numerical analysis, surrogate methods, and the multi-objective evolutionary algorithm. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by four geometric design variables, the injection angle of the hole, the lateral expansion angle of the diffuser, the forward expansion angle of the hole, and the ratio of the length to the diameter of the hole, to maximize the film-cooling effectiveness compromising with the aerodynamic loss. The objective function values are numerically evaluated through Reynolds- averaged Navier-Stokes analysis at the designs that are selected through the Latin hypercube sampling method. Using these numerical simulation results, the Response Surface Approximation model are constructed for each objective function and a hybrid multi-objective evolutionary algorithm is applied to obtain the Pareto optimal front. The clustered points from Pareto optimal front were evaluated by flow analysis. These designs give enhanced objective function values in comparison with the experimental designs.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.5
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• pp.437-444
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• 2015

In simulation-based circuit optimization, many simulation runs may be wasted while evaluating infeasible designs, i.e. the designs that do not meet the constraints. To avoid such a waste, this paper investigates the use of support vector machine (SVM) classifiers in predicting the design's feasibility prior to simulation and the optimal selection of the SVM parameters, namely, the Gaussian kernel shape parameter ${\gamma}$ and the misclassification penalty parameter C. These parameters affect the complexity as well as the accuracy of the model that SVM represents. For instance, the higher ${\gamma}$ is good for detailed modeling and the higher C is good for rejecting noise in the training set. However, our empirical study shows that a low ${\gamma}$ value is preferable due to the high spatial correlation among the circuit design candidates while C has negligible impacts due to the smooth and clean constraint boundaries of most circuit designs. The experimental results with an LC-tank oscillator example show that an optimal selection of these parameters can improve the prediction accuracy from 80 to 98% and model complexity by $10{\times}$.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.814-820
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• 2009

The arrangement of the general 12-button cellular phone keypad is unified with one or two kind. In general, the several alphabets are arranged in one key. When inputting an English, countries which do not speak English use multi-tap method. We can input next alphabet by pressing key repeatedly. We address the problem of finding multi-tap-based keypad designs which minimize the number of key presses for various case. Genetic algorithms is proposed method for optimal keypad designs. We are to maintain the number of keys, which is ranged from 8 to 12. We also show experimental using non-alphabetically-constrained and alphabetically-constrained arrangement, respectively. Finally, we give improved keypad designs.

• Korean Institute of Interior Design Journal
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• v.18 no.3
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• pp.84-92
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• 2009

Sociological, technical, and organizational changes have affected the culture of business in many ways. These changes are now encouraging new concepts in the workplace environment such as emotional approaches for a more creative and humanistic workplace let alone enhancing image of the company. The aim of this study is to understand current situations of common office areas and serve as a stepping stone for designing more creative and stimulating work environments. The study first examines concepts of new office designs in our modem society, then defines categories such as territorial fuzziness, eco-friendly, fun and play. Secondly, by using content analysis as research tool the researchers have investigated how the conceptual categories and detailed design presentation methods are shown in workplace designs in Korea. Scope of study is limited to 39 office design projects from 2002-2008 presented in the Korean monthly magazine 'Interiors'. As results. territorial fuzziness was found to be most popular method while play the least. For application wise, meeting rooms, rest area and hallways were places where these concepts appear the most. Even though, these new approaches in office designs can be found in our domestic offices, still more experimental and active approach seems to be needed.