• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.113-115
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• 2003

The electric power industry throughout the world is undergoing considerable changes from the vertically integrated utility structure to the deregulated market. However, the deregulated electricity market is operated with respect to theory of economical efficiency, and therefore, the system operator requires data with fast contingency ranking for security of the bulk power system. This paper presents fast calculation method for determining contingency ranking using the weather dependant probabilistic risk index(PRI). The probabilistic risk index can be classified into normal weather and adverse weather. This paper proposes calculation method using the probabilistic risk index in determining contingency ranking requiring for security under the deregulated electricity market.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.1093-1097
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• 2020

A composite iodine sorbent was obtained in the form of porous polymer matrix with activated carbon particles impregnated with triethylenediamine deposited on its surface. A comparative assessment of the radioactive methyliodide capturing efficiency by the composite sorbent and a sample of industrial charcoal sorbent was conducted. It was shown that under the selected testing conditions, the hydraulic resistance of the composite sorbent is lower, and the sorption capacity is higher than that of the industrial charcoal sorbent. A method for comparing the effectiveness of iodine sorbents, based on the calculation of the ratio of the sorption capacity index to the minimum capacity index, needed for the required purification degree was proposed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.97-102
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• 2000

This experiment was conducted to investigate the changes of harvest index and the relationship between harvest index and yield determination factors by different planting times in the determinate soybean cultivars, Shinpaldal and Danbaeg. Optimum planting were 23 May in 1995 and 1996. Late planting were 13 June in 1995 and 6 June in 1996. Growth period from planting to physiological maturity (R7) was shortened as planting time was delayed in two cultivars due to shortening of reproductive growth period in Shinpaldal, and of vegetative growth period in Danbaeg. Stem weight was distinctly decreased in late planting compared to optimum planting, but seed weight of both cultivars was not different between planting times. Also, seed number per pod and harvest index were significantly increased in late planting and the high correlation was found between two factors. It was suggested that increase of harvest index in late planting would be related with high assimilate use efficiency due to increase of sink capacity. The results of correlation and principal component analysis for yield determination factors showed that main factor on yield determination was pod number per plant at R5 stage associated with dry matter accumulation during early reproductive growth period, seed number per pod and harvest index were the second factor, and one hundred seed weight was the third factor. The result of this experiment indicated that yield determination in soy-bean was dependent mainly on pod number per plant related to dry matter accumulation by early reproductive growth period, and the increase of seed number per pod and harvest index could compensate for yield decrease by shortening of vegetative growth period in late planting. Such result suggests that optimum planting date can be delayed from mid May to early June in improved soybean cultivars in Korea.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.349-356
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• 2012

This study aimed to assess the effects of progressive lumbar stability exercises and lumbar stability exercises on changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index in soccer players. Ten subjects were assigned to undergo training in each of the 2 groups, namely, the progressive lumbar stability exercise group and lumbar stability exercise group. Each intervention session lasted for 30 min, and 4 sessions were conducted in a week for 6 weeks for soccer players of S. University in Jeonnam, Korea. Changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index were measured using ultrasound and surface electromyogram. The results of the ultrasound measurement for the transversus abdominis muscle thickness indicated that progressive lumbar stability exercises were more effective than lumbar stability exercises. The results of the lower extremity muscle fatigue index measurements using surface electromyogram indicated that the fatigue index decreased in the progressive lumbar stability exercise group. Progressive lumbar stability exercise is believed to have put more workload during the shaking of the limbs, leading to increased stability and increased efficiency of the lower extremity muscle, thereby decreasing the fatigue index. Therefore, progressive lumbar stability exercises can be an effective measure for preventing injuries and improving the game performance of sports players by increasing the transversus abdominis muscle thickness and decreasing the lower extremity muscle fatigue index.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1122-1131
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• 2000

The efficiency of thesytem depends upon an accurate extraction capability of index terms in the system of information search or in that of automatic index. Therefore, extraction of accurate index terms is of utmost importance. This report presents the generation methods of composition noun for efficient index term extraction by using words of high frequency appearance, so that the right documents can be found during information search. For the sake of presentation of this method, index terms of composition noun shall be extracted by applying the rule of composition and disintegration to the nouns with high frequency of appearance in the documents, such as those with upper 30%∼40% of frequency ratio. In addition, for he purpose of effecting an inspection of validity in relation to a composition of high frequency nouns such as those with upper 30∼40% of frequency ratio as presented in this report, it proposes an adequate frquency ratio during noun composition. Based upon the proposed application, in this short documents with less than 300 syllables, low frequency omissions were noticed, when composed with nouns in the upper 30% of frequency ratio; whereas the documents with more than 30 syllables, when composed with nouns in he upper 40% of frequency ration, had a considerable reduction of low frequency omissions. Thus, total number of index terms has decreased to 57.7% of these existing and an accurate extraction of index terms with an 85.6% adequacy ratio became possible.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.437-444
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• 2015

Satellite selection and exclusion techniques have been applied to the global navigation satellite system (GNSS) with the aim of achieving a balance between navigational performance and computational efficiency. Conventional approaches to satellite selection based on the best dilution of precision (DOP) are excessively computational and complicated. This paper proposes a new method that applies a geometric sensitivity index of individual GNSS satellites. The sensitivity index is derived using the inner product of the line of sight (LOS) vector of each satellite. First, the LOS vector is computed, which accounts for the geometry between the satellite and user positions. Second, the inner product of each pair of LOS vectors is calculated, which indicates the proximities of the satellites to one another. The proximity can be determined according to the sensitivity of each satellite. A post-processing test was conducted to verify the reliability of the proposed method. The proposed index and the results of a conventional approach that measures the dilution of precision (DOP) were compared. The test results demonstrate that the proposed index produces results that are within 96% of those of the conventional approach and reduces the computational burden. This index can be utilized to estimate the sensitivity of individual satellites, obtaining a navigation solution. Therefore, the proposed index applies to satellite selection and exclusion as well as to the sensitivity analyses of multiple GNSS applications.

• Korea-Australia Rheology Journal
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• v.20 no.2
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• pp.79-88
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• 2008

In this study, we focus on the improvement of the filling efficiency in injection molding by application of ultrasonic vibration. While studies about the filling efficiency of typical filling processes in the injection molding have been widely performed, there have been only few studies about the filling efficiency of an ultrasonic process. The effect of the ultrasonic vibration is an important process condition, which influences the flow characteristics of polymer melt. This new condition even affects well-known injection conditions such as cavity pressure, injection temperature and mold temperature. For this study, we carried out a numerical analysis by appropriate modeling and analysis of the ultrasonic process in the filling process. To verify this numerical analysis, we compared the numerical results with the experimental data. Also, we analyzed the filling process in a thin cavity using this numerical analysis. To understand the flow characteristics of polymer melt in the ultrasonic process, we substituted real and complex vibration conditions with simplified and classified conditions according to the position of vibrating cavity surfaces and the phase difference between two opposing cavity surfaces. We also introduced MFR (melt flow ratio) as a new index to estimate the filling efficiency in the ultrasonic process.

• Health Policy and Management
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• v.23 no.1
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• pp.78-89
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• 2013

This study empirically analyze efficiency and productivity changes of public hospitals of Korea using data envelopment analysis/Window model and global Malmquist indices model. We use the ten-year data from 2001 to 2010 of 30 regional public hospitals listed database from the Association of Korean Regional Public Hospitals. The main focuses are to reveal whether the technical inefficiency are improved as time goes by, and efficiency and productivity are affected by environmental factors. The results can be summarized as follows. First, the efficiencies of public hospitals rise in trend as time passes. Second, regional public hospitals show the different average efficiencies according to their regional type, hospital type, operational type, medicaid type, and demand and supply conditions by Mann-Whitney U-tests. Third, technical efficiency changes mainly contribute to 4.4% annual average growth rate of productivity of regional public hospitals during that period. Our findings have some policy implications. It is confirmed that there exist some environmental inefficiencies, and those inefficiencies can not be overcome through just improving the inner management system. Thus, policy and institutional changes are necessary for regional public hospitals to improve efficiency and productivity overall.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.355-364
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• 2022

The effect of technological innovation on the high-quality development of the producer services industry depends on whether or not technical innovation efficiency plays a key role. This study looks at the impact of technological innovation and financial technology (fintech) on the development of high-quality producer services in Fujian Province from 2010 to 2019. The efficiency of technological innovation is measured using Data Envelopment Analysis (DEA) and the Malmquist productivity index. The mean overall innovation efficiency score is 0.639, meaning that Fujian accounts for 36.1% of resource utilization inefficiencies and that there are significant differences in technological innovation efficiency between cities. The findings show that high-quality producer services industries benefited from innovation efficiency, but that the influence of technological innovation efficiency is insignificant. This demonstrates that financial innovation has not been able to completely enhance the development level of the producer services industry. This may be due to the unreasonable output structure of technological innovation and the low industrial transformation rate of technological achievements. This study advocates that the R&D fund allocation structure be optimized. That technological innovation can improve the high-quality development of the producer services industry is a consensus within the academic community.