• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.266-272
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• 2011

Real Time Pricing(RTP) is used not only to stabilize the price volatility in electricity market, but to hedge the price risk for Load Serving Entity(LSE). This paper presents an efficient method to reduce the risk of the price volatility in real-time electricity market. For designing the RTP, load patterns of customer are calculated by applying the demand elasticity and customer's utility is also analyzed to compute the RTP revenue through the risk-attribute of the LSE. In the end, the distribution of the LSE's profits can be evaluated to lead the optimal RTP value, depending on the level of customer's participation. Results from the case study based on PJM data are reported to illustrate the proposed method.

• Korean System Dynamics Review
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• v.5 no.1
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• pp.49-71
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• 2004

Demand-side Management can be defined as'any utility activity aimed at modifying customers' use of energy to produce desired changes in the utility's load shape'. Customers benefit by being able to control energy costs and improve quality of life and become more productive. Utilities benefit from DSM's value as a resource that enhances asset utilization and reduces both fuel costs and environmental emissions. The scope of DSM includes load management through rate schedules and conservation by improving energy effciency and using electricity consumption effectively. This paper study the DSM resource evaluation and customer behavior analysis todesign the DSM Program plan in response to customer needs. We develop basic system dynamics model to analysis the customer behavior based on a survey research. The DSM Program participants in the Hi- efficiency Inverter, Electric motor and efficient lighting applicancies operating by Conservation program 2002 become the survey objects. DSM resource evaluation evaluate firstt the distribution potentialities of each machine and then forecast the degree of diffusion. We apply the system dynamic approach to simulate the dynamic DSM market situation at the domestic beginning. This model will give the energy Planner the opportunity to create different scenarios for DSM program planning. Also it will lead to increased understanding of the dynamic DSM market

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.882-889
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• 2010

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow (3POPF). 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique for 3POPF, this paper adopts a simulation-based method of particle swarm optimization (PSO). In the PSO based 3POPF, a utility function needs to be defined for evaluation of the degree in operational improvement of each particle's current position. To evaluate the utility function, in this paper, NR-based 3 phase power flow algorithm was developed which can deal with looped distributed generation systems. In this paper, illustrative examples with a 5-bus and a modified IEEE 37-bus test systems are given.

• Journal of Acupuncture Research
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• v.38 no.4
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• pp.312-319
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• 2021

Background: Lumbar herniated intervertebral disc (LHIVD) is a frequently presented condition/disease in Korean medical institutions. In this study, the economics of thread embedding acupuncture (TEA) was evaluated in a randomized controlled trial comparing TEA with sham TEA (STEA). Methods: This economic evaluation was analyzed from a limited social perspective, and the per-protocol set was from a basic analysis perspective. The cost-effectiveness analysis was based on the change in visual analog scale score, and the cost-utility analysis was based on the quality-adjusted life years. The final results were expressed as the average cost-effectiveness ratio and incremental cost-effectiveness ratio, and furthermore sensitivity analysis was performed to confirm the robustness of the results observed. Results: The cost-effectiveness analysis showed that TEA was 9,908 won lower than STEA, while the decrease in 100 mm visual analog scale score was 8.5 mm greater in the TEA group compared with the STEA group (p > 0.05). The cost-utility analysis showed that TEA was 9,908 won lower than STEA, while the quality-adjusted life years of TEA was 0.0026 years higher than STEA (p > 0.05). These results were robust in the sensitivity analysis, but were not statistically significant. Conclusion: In treating LHIVD, TEA appeared to have cost-effectiveness and cost-utility compared with STEA. However, there were no significant differences between the groups in terms of cost, effectiveness, and utility indicators. Therefore, results must be interpreted prudently; this study was the 1^st to conduct an economic evaluation of TEA for LHIVD.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.127-135
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• 2009

Most traffic information that drivers receive while driving are stored in their short-term memory and disappear within a few seconds. Contemporary modeling approaches using a dummy variable can't fully explain this phenomenon. As such, this study proposes to use utility functions of real-time in-vehicle traffic safety information (IVTSI), analyzing its safety impacts based on empirical data from an on-site driving experiment at signalized intersection approach with a limited visibility. For this, a driving stability evaluation model is developed based on driver's driving speed choice, applying an ordered probit model. To estimate the specified utility functions, the model simultaneously accounts for various factors, such as traffic operation, geometry, road environment, and driver's characteristics. The results show three significant facts. First, a normal density function (exponential function) is appropriate to explain the utility of IVTSI proposed under study over time. Second, the IVTSI remains in driver's short-term memory for up to nearly 22 second after provision, decreasing over time. Three, IVTSI provision appears more important than the geometry factor but less than the traffic operation factor.

• Journal of Korean Society of Forest Science
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• v.98 no.3
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• pp.297-304
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• 2009

Bukhansan National Park is facing dramatic increase of visitors since no entrance fee charge effected in January of 2007. This study was carried out to estimate socio-psychological carrying capacity of Bukhansan National Park based on marginal utility theory model, provide management tactics by stages. 512 visitors to Bukhansan National Park were surveyed during the October of 2008. The data analysis indicated that sociopsychological carrying capacity was estimated as approximately 65,000 people per day for Bukhansan National Park.

• Journal of the Korea Fashion and Costume Design Association
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• v.12 no.4
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• pp.183-195
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• 2010

The purpose of this study is to find out the difference of evaluation of product and service quality according to consumers' attitude toward price in internet clothing purchase. This study surveyed 400 male and female consumers in their 20s-30s for empirical analysis in August 2010 who have ever purchased clothing through internet shopping malls. For statistical analysis, descriptive statistics, factor analysis, ANOVA analysis, Duncan test and cluster analysis are carried out using SPSS for Windows 12.0. The results are as follows. First, consumers' attitude toward price dimensions in internet clothing purchase are found 6 factors of sales proneness, price-prestige, price-comparison, low price, utility value and pricequality. Second, based on the attitude toward price dimensions, consumers are categorized into utility value seeking, sales price seeking, multi-dimension price seeking, lack price consciousness, low price seeking group. Third, there are significant differences in product quality and service quality depending on attitude toward price-based consumer types. In particular, sales price seeking and multi-dimension price seeking groups have higher values on product and service quality than other groups. The results of this study will help internet fashion mall businesses to develop price strategy and manage product and service quality.

• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.605-619
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• 2010

Caching of frequently accessed data in multi-hop ad hoc environment is a technique that can improve data access performance and availability. Cooperative caching, which allows sharing and coordination of cached data among several clients, can further en-hance the potential of caching techniques. In this paper, we propose a fuzzy cooperative caching scheme in mobile ad hoc networks. The cache management of the proposed caching scheme not only uses adaptively CacheData or CachePath based on data sim-ilarity and data utility, but also uses the replacement manager based on data pro t. Also, the proposed caching scheme uses a prefetch manager. When the TTL of the cached data expires, the prefetch manager evaluates the popularity index of the data. If the popularity index is larger than a threshold, the data is prefetched. Otherwise, its space is released. The performance of the proposed scheme is evaluated analytically and is compared to that of other cooperative caching schemes.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1181-1185
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• 2006

By using two different computer simulation methods, of which one produces exact results while the other is based on the Wilemski-Fixman closure approximation, we evaluate the utility of closure approximation in calculating the rates of diffusion-controlled reactions involving a reactant with multiple reaction sites. We find that errors in the estimates of steady-state rate constants due to closure approximation are not so large. We thus propose an approximate analytic expression for the rate constant based on the closure approximation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.61-77
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• 2019

If a new utility tunnel is planned for high density existing urban areas in Korea, a rational decision-making process such as the determination of optimum design capacity by using the feasibility evaluation system based on quantitative evaluation indexes and the economic evaluation is needed. Thus, the previous study presented the important weight of individual higher-level indexes (3 items) and sub-indexes (16 items) through a hierarchy analysis (AHP) for quantitative evaluation index items, considering the characteristics of each urban type. In addition, an economic evaluation method was proposed considering 10 benefit items and 8 cost items by adding 3 new items, including the effects of traffic accidents, noise reduction and socio-economic losses, to the existing items for the benefit cost analysis suitable for urban utility tunnels. This study presented a quantitative feasibility evaluation method using the important weight of 16 sub-index items such as the road management sector, public facilities sector and urban environment sector. Afterwards, the results of quantitative feasibility and economic evaluation were compared and analyzed in 123 main road sections of the Seoul. In addition, a comprehensive evaluation method was proposed by the combination of the two evaluation results. The design capacity optimization program, which will be developed by programming the logic of the quantitative feasibility and economic evaluation system presented in this study, will be utilized in the planning and design phases of urban community zones and will ultimately contribute to the vitalization of urban utility tunnels.