• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.19-19
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer′s utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.6
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• pp.277-284
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• 2002

In this paper the authors explore the effect of bandwidth sharing to the utility of the customer for the best-effort Internet services and draw a basis for the pricing principle in Internet Protocol networks. Especially, we investigate the behavior of a customer's utility in case an arbitrary amount of additional bandwidth is allowed to each customer for the elastic traffic, which is the typical example of the non-real time Internet data traffic. After drawing the utility curve, which will be proved to follow the concave curve, we will apply it to the pricing of Internet traffic. Finally, via numerical experiments, we will illustrate the validity and implication of the proposed method.

• Journal of Power Electronics
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• v.10 no.4
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• pp.428-433
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• 2010

This paper proposes a harmonics reduction technique for the input currents of three phase PWM converters. The quality of the phase angle information on the utility voltage connected to the PWM converters affects their control performance. Under a distorted utility voltage, the extracted phase angle based on the synchronous reference frame PLL method is distorted. This causes large harmonics in the input currents of a PWM converter. In this paper, a harmonics reduction method that makes the input currents in the PWM converter sinusoidal even under distorted utility conditions is proposed. By the proposed method, without additional hardware, the THD (Total Harmonic Distortion) of the input currents can be readily limited to below 5% which is the harmonic current requirements of IEEE std. 519. Its validity is verified by simulations and experimental results.

• Journal of Korea Technology Innovation Society
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• v.2 no.2
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• pp.201-218
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• 1999

The article contains an introduction of possibility of applying Multi-Attribute Utility Theory(MAUT) for priority setting of R&D projects. MAUT is compared with AHP, which is widely used recently. These two techuiques are applied to set priorities of R&D projects In a Government-funded Research Institute. Six criteria are chosen from consultation with decision makers. They are composed of 1) validity as representative projects, 2) possibility of resource mobilization, 3) spillover effect of developed technologies, 4) possibility of success, 5) scope of participation and 6) clarity of research goal. To set priorities of R&D projects, SMART(Simple MultiAttribute Rating Technique) and DVM(Difference Value Measurement) out of many MAUT methods are used to design the utility function and to determine the weights among criteria. The aggregation model is additive on the assumption the criteria are independent. AHP executes pairwise comparisons for criteria and alternatives. From the results of the case study, the results and theoretical characteristics are compared.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.271-273
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• 2005

Islanding of PV systems occurs when the utility grid is removed but local sources continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. Also, this can present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.436-446
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• 2017

This study was performed to verify the validity and utility of the Korean Behavior Rating Inventory of Executive Function-Preschool Version(BRIEF-P). The BRIEF-P is one of the most used instruments to measure Executive Function(EF) and a teacher-rating assessment method designed to measure the executive function of preschoolers(age 2-5). A total of 200 preschoolers(104 boys, 96 girls; recruited aged 3 to 5years) participated. Confirmatory factor analysis was carried out to evaluate the model structure. Correlation analysis was done to verify the concurrent validity. In the results, the model fit indexes were good with the five BRIEF-P subscales (that is, inhibit, shift, emotional control, working memory, plan/organize). The internal consistency of the BRIEF-P five subscales were supported. As a results, the Korean Behavior Rating Inventory of Executive Function-Preschool Version(BRIEF-P) was confirmed to be a reliable and valid assessment tool to measure executive function in preschoolers.

• Korean Journal of Occupational Health Nursing
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• v.26 no.1
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• pp.1-9
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• 2017

Purpose: This study was conducted to evaluate the validity of the 'Enterprise Health Promotion Index', a tool for assessing health promotion activities of worksite developed by the Ministry of Employment and Labor and the Korea Occupational Safety and Health Agency. Methods: This is designed a methodological study that evaluates the validity of the Enterprise Health Promotion Index. For this study, a questionnaire survey was conducted for the workplace health professional and safety professional, and a total of 297 data were extracted as final data. We developed the informal health promotion needs and activity measurement tools. The correlation coefficient between the score of the enterprise health promotion index and the score of the informal health promotion tool was analyzed for the criterion validity evaluation. Results: The criterion validity of the Enterprise Health Promotion Index and activity index were supported by finding moderate (r=.597) and high (r=.783) correlation coefficient. However, the requirement index has low levels of criterion validity (r=.364). Conclusion: Based on these results, we suggest to improve the utility of the corporate health promotion index by developing user manual, active public relations, and providing briefing sessions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3390-3397
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• 2010

The purpose of this study was to evaluate the validity and utility of the Korean-Ages and Stages Questionnaires(K-ASQ) as a screening tool for detecting developmental delay of preschool child in community. Informed consents from parents of 229 children were received for the process of the study. The subjects were 229 parents and the children of three to five years old who did not have reported genetic diseases or developmental delays. The result of this study, validity were calculated for the K-ASQ sensitivity 0.41%, specificity 0.76%, hyper-referral 0.14%, hypo-referral 0.21%. Predictive value of delayed development were K-ASQ 0.70% and that of normal development were K-ASQ 0.77%. K-ASQ can be feasibly used in the setting of health clinic and be the highly predictive criteria for delayed development and normal development.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.103-112
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• 2006

Priority-based network service has been widely adopted for the Internet traffic management in the context of IETF differentiated services, and computing optimal prices for such priority-based service is the key topic in many pricing literature. While the equilibrium analysis has been commonly used to this end, many have criticized the validity of the underlying assumption of equilibrium analysis that user utility functions are precisely known. In this paper, we propose a solution for bridging the gap between the existing theoretical work on optimal pricing and the unavailability of precise user utility information in real networks. In the proposed method, the service provider obtains more and more accurate estimates of user utility functions from the initial imprecise knowledge by iteratively changing the price of service levels and observing the users' decisions under the changed price. Our contribution is two-fold. First, we have developed a general principle for estimating the user utility functions. Second, we have developed a novel method for setting the prices that can optimize the extraction of the knowledge about user utility functions. The extensive simulation results demonstrate the effectiveness of our method.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.1
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• pp.81-88
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• 2007

In this paper, a new single-phase utility-interactive inverter system for residential power generation with fuel cell is proposed. The proposed inverter system is not only capable of working in both stand-alone and grid-connected mode, but also ensures smooth and automatic transfer between the two modes of operation. The proposed control method has little steady-state error and good transient response characteristic. Also, the control method can be implemented using low-cost, fixed point DSP since it has simpler structure, smaller amount of calculation, and smaller number of sensors. The controller for the proposed utility-interactive inverter system is described, and the validity is verified through simulation and experiment.