• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.93_94
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• 2009

Load modeling has a significant impact on power system analysis and control. Estimating model parameters can be considered as important as stability analysis itself for accurate analysis and control. This paper presents a method for estimating parameters for load models, which include static and dynamic parts, based on particle swarm optimization. The method effectively searches a suitable set of parameters minimizing the fitness function. This paper applies the method to simulation data obtained from 8-bus test system including induction motors.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.63-77
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• 2003

Group buying is one of the most popular transaction patterns on the internet at least in Korea. Nevertheless, it is hard to find academic researches for it in view of consumer behavior. In this paper, we analyze factors which determine consumer's attitude toward and intention of participation in Internet group buying by comparison of Internet individual one. For this purpose, we propose “lowering price”, “decreasing risk” and “reducing transaction cost” as relative advantages and "lack of product assortment" and "delay of time" as relative disadvantages over individual buying on the Internet. For empirical test, Internet users who have some experiences of individual buying but not group ones on the Internet are surveyed and analyzed. In result, a satisfying model fitness for structural equation model is derived and most hypotheses except the relationship between "decreasing risk" and "attitude toward Internet group buying" are accepted. Our results provide not only academic contribution by suggestion of a research framework but also practical insight by discussion of diverse features in Internet group buying.verse features in Internet group buying.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.125-130
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• 2001

In this paper, we propose a new type of evolution strategies combined with reinforcement learning. We use the variances of fitness occurred by mutation to make the reinforcement signals which estimate and control the step length of mutation. With this proposed method, the convergence rate is improved. Also, we use cauchy distributed mutation to increase global convergence faculty. Cauchy distributed mutation is more likely to escape from a local minimum or move away from a plateau. After an outline of the history of evolution strategies, it is explained how evolution strategies can be combined with the reinforcement learning, named reinforcement evolution strategies. The performance of proposed method will be estimated by comparison with conventional evolution strategies on several test problems.

• Journal of the Korean Home Economics Association
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• v.45 no.4
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• pp.97-112
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• 2007

The purpose of this study was to develop a Parenting Self-Efficacy Scale for mothers of 5- to 7-year -old preschool children. After 43 items of the preliminary scale were analyzed for their fitness of structure based on the chi-square test and Cramer's V coefficients, and 27 were selected as the final set for the questionnaire. Further factor analysis on these 27 items confirmed the selection of 26 of the 27 items with a four-factor structure : communication, teaching, general parenting self-efficacy, and control. The internal reliability was evaluated to show a confidence level of .92 for the overall items and a range of .70 to .86 for each individual factor.

• Korean Journal of Adult Nursing
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• v.22 no.1
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• pp.90-102
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• 2010

Purpose: The purpose of this study was to identity factors affecting patient adherence and to develop an explanatory model for patient adherence in patients with spinal cord injury. 8 Variables that were based on the previous research and a review of literature were used to construct hypothetical model. Social support, economic status, perceived barrier, patient provider relationship and rehabilitation related knowledge were the exogenous variables, depression, self-efficacy and patient adherence were the endogenous variables. Methods: Data form 117 patients with SCI were analysed to test the hypothetical model, using SAS and LISREL 8.53 program. Results: The overall fitness of the model was good (GFI=.991, AGFI=.915, NNFI=1.299, NFI=.953, p=.632) Depression, powerlessness, economic status were the strong factors influencing patient adherence. Powerlessness was significant factors for self-efficacy. Conclusion: To improve of patient adherence should focus on nursing intervention for depression, powerlessness and economic status.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.3
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• pp.219-223
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• 2009

This paper prescribed the structural integrity of the API 5L X65 pipeline subjected to tensile pre-strain. The effects of pre-strain on the mechanical properties of API 5L X65 pipe were substantially investigated through a variety of the experimental procedures. Axial tensile pre-strain of 1.5, 5 and 10% was applied to plate-type tensile specimens cut from the pipe body prior to mechanical testing. Tensile test revealed that yield strength and tensile strength were increased with increasing tensile pre-strain. The increasing rate of the yield strength owing to the pre-strain is greater than that of the tensile strength. However, the pre-strain up to 5% had a little effect on the decreasing of the fracture toughness. The structural integrity of the API 5L X65 pipeline subjected to large plastic deformation was evaluated through the fitness-for service code.

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.185-191
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• 2016

Purpose: The purpose of this study were to evaluate the quality of dental prostheses printed by 3-dimensional printing system. Methods: Mater model was prepared and ten study models were fabricated. Ten single crowns were printed by 3D-printing system(Resin group) and another ten single crowns using casting method were manufactured(Metal group). The marginal adaptation of single crowns were measured using by silicone replica technique. Silicone replicas were sectioned four times. The marginal adaptations were evaluated using by digital microscope. Statistical analyses were performed with Mann-Whitney test(${\alpha}=0.05$). Results: $Mean{\pm}standard$ deviations of all marginal adaptations were $92.1(20.0){\mu}m$ for Metal group and $69.7(12.3){\mu}m$ for Resin group. Two groups were no statistically significant differences(p>0.05). Conclusion: Marginal adaptation of single crowns printed by 3D-printing system were ranged within the clinical recommendation.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.266-272
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• 2006

Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed for 67 molecules of 2-amino-benzothiazole-6-anilide derivatives against lymphocyte-specific protein tyrosine kinase (P56 LCK). The molecular field analysis (MFA) and receptor surface analysis (RSA) were employed for QSAR studies and the predictive ability of the model was validated by 15 test set molecules. Structure-based investigations using molecular docking simulation were performed with the crystal structure of P56 LCK. Good correlation between predicted fitness scores versus observed activities was demonstrated. The results suggested that the nature of substitutions at the 2-amino and 6-anilide positions were crucial in enhancing the activity, thereby providing new guidelines for the design of novel P56 LCK inhibitors.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.55-63
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• 2006

The purpose of this study was to investigate the effects of vibration exercise using surface electromyography. Seven male collegiate wrestlers were participated in this study. Each subject stood on the platform and the vibration was induced for 1min. WEMG8 EMG system was used to record muscle activity from Vastus lateralis, Biceps Femoris, Tibialis Anterior, and Gastrocnemius. The EMG data were sampled for 30 sec. during non-vibration and vibration half squat position, respectively. The raw data were band pass filtered to remove noise and full wave rectified Paired sample t-test were performed to see the differences of maximum and average EMG between non-vibration and vibration trials. The results indicated that vibration produced much more muscle contraction than that of non-vibration trial for all selected muscles even though the significant difference was found only from Biceps Femoris. This phenomenon was due to the individual differences so care must be taken to evaluate vibration intensity and position before personal training.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.4
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• pp.31-41
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• 2003

This paper deals with a cell formation problem for a set of m-machines and n-processing parts. Generally, a cell formation problem is known as NP-completeness. Hence the cell formation problem with multiple objectives is more difficult than single objective problem. The paper considers multiple objectives; minimize number of intercell movements, minimize intracell workload variation and minimize intercell workload variation. We propose a multiple objective genetic algorithms(MOGA) resolving the mentioned three objectives. The MOGA procedure adopted Pareto optimal solution for selection method for next generation and the concept of Euclidean distance from the ideal and negative ideal solution for fitness test of a individual. As we consider several weights, decision maker will be reflected his consideration by adjusting high weights for important objective. A numerical example is given for a comparative analysis with the results of other research.