• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.847-858
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• 2015

Control strategy and corresponding parameters have significant impacts on the overall technical and economic characteristics of composite energy storage systems (CESS). A better control strategy and optimized control parameters can be used to improve the economic and technical characteristics of CESS, and determine the maximum power and stored energy capacity of CESS. A novel coordinated control strategy is proposed considering the coordination of various energy storage systems in CESS. To describe the degree of coordination, a new index, i.e. state of charge coordinated response margin of supercapacitor energy storage system, is presented. Based on the proposed control strategy and index, an optimization model was formulated to minimize the total equivalent cost in a given period for two purposes. The one is to obtain optimal control parameters of an existing CESS, and the other is to obtain the integrated optimal results of control parameters, maximum power and stored energy capacity for CESS in a given period. Case studies indicate that the developed index, control strategy and optimization model can be extensively applied to optimize the economic and technical characteristics of CESS. In addition, impacts of control parameters are discussed in detail.

• 대한의용생체공학회:의공학회지
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• 제28권6호
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• pp.750-755
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• 2007

The linear SEF (Spectral Edge Frequency) parameter and spectrum analysis method can not reflect the non-linear of EEG. This method can not contribute to acquire real time analysis and obtain a high confidence in the clinic due to low discrimination. To solve the problems, the development of a new index is carried out using the bispectrum analyzing the EEG including the non-linear characteristic. At the bispectrum analysis of the 2 dimension, the most significant's power spectrum density peaks appeared much at the specific area in awake and anesthesia state. Because many peaks are showed at the specific area in the frequency coordinate, these points are used to create the new index. Range of the index is 0-100. At the anesthesia, the index is 20-50 and at the awake, the index is 90-60. New index can discriminate the awake and anesthesia state.

• Geomechanics and Engineering
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• 제4권3호
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• pp.219-227
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• 2012

Pavement management systems require systematic monitoring of pavement surfaces to determine preventive and corrective maintenance. The process involves the accumulation of large amounts of visual data, typically obtained from site visitation. The pavement surface condition is then correlated to a pavement distress index that is based on a scoring system previously established by state or federal agencies. The scoring system determines if the pavement section requires maintenance, overlay or reconstruction. One of the surface distresses forming part of the overall pavement distress index is the Alligator Crack Index (AC Index). The AC Index involves the visual evaluation of the crack severity of a section of a pavement as being low, medium, or high. This evaluation is then integrated into a formula in order to obtain the AC Index. In this study a quantification of the visual evaluation of the severity of alligator cracking is carried out using photographs and the fractal dimension concept from fractal theory. Pavements with low levels of cracking were found to have a fractal dimension equal to 1.051. Pavements with moderate levels of cracking had a fractal dimension equal to 1.1754. Pavements with high degrees of cracking had a fractal dimension that varied between 1.5037 (high) and 1.7111 (very high). Pavements with a level of cracking equal to 1.8976 represented pavements that disintegrated and developed potholes. Thus, the visual evaluation of the state of cracking of a pavement (the AC Index) could be enhanced with the use of the fractal dimension concept from fractal theory.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1248-1257
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• 2014

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

• 수산해양기술연구
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• 제54권4호
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• pp.287-295
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• 2018

The ichthyoplanktons were sampled to study distribution of the ichthyoplankton in coastal waters of Nanji-Island in August and November 2015 and January and May 2016. During the study, fish eggs of eight different species were collected. Engraulis japonicus was the most dominant species which accounted 44.80%. Sebastes schlegeli comprised 31.39% of the total larvae and juveniles. The diversity index of species per month of the collected juveniles at Nanji Island from 2015 to 2016 was 0.598-1.770 and the evenness index was 0.432-0.761. In case of dominance index was 0.619-0.897 against the evenness index. The analyzed species diversity index by the each station was 0.818-1.945 and the dominance index was 0.492-0.897 against the species diversity index. The months of August and May exhibited similar results. In addition, the community structure was very similar in state 2 and state 3.

• 한국지반공학회논문집
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• 제27권9호
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• pp.37-46
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• 2011

압축지수는 점토의 압축특성을 나타내는 대표적인 물성치로, 압밀시험을 통해 직접 결정하거나 기본 물성으로부터 경험적으로 추정한다. 본 연구에서는 부산 및 인천점토의 퇴적상태를 파악하고 이것이 압축지수 추정식에 미치는 영향에 분석하였다. 이를 위해 부산 및 인천 점토의 재성형점토 압밀시험을 수행하고 자연점토 압밀시험 결과를 분석하였다. 분석결과 부산점토는 SCL보다 높은 간극지수를, 인천점토는 SCL보다 낮은 간극지수를 나타냈다. 퇴적상태를 나타내는 ${\Delta}e_r$을 압축지수 추정오차와 비교한 결과 액성한계 및 소성지수로 추정한 압축지수의 추정오차는 ${\Delta}e_r$이 증가함에 따라 감소하는 경향이 나타났다. 본 연구에서는 이러한 관계를 이용하여 부산 및 인천점토의 압축지수를 보다 정확히 추정할 수 있는 방법을 제안하였다.

• 한국치위생학회지
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• 제11권4호
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• pp.499-509
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• 2011

Objectives : The purpose of this study was to provide some information on down-to-earth oral health policy to improve the systemic health involving oral health and the quality of life in Korean adults. Methods : The third-year data of the 4th National Health and Nutrition Survey in 2009 were analyzed, and $x^2$(Chi-square) test was carried out to see whether there would be any gaps in subjective oral health status according to demographic characteristics, systemic health state, frequency of eating between meals and oral health behavior. In terms of the DMFT index, one-way ANOVA was utilized, and then Scheffe post-hoc analysis was conducted. Besides, multiple regression analysis was made to grasp the relationship of oral health behavior to subjective oral health state and the DMFT index. Results : The demographic characteristics, systemic health status and oral health behavior had a significant relationship to both of subjective oral health status and the DMFT index. As a result of analyzing the relationship of oral health behavior to subjective oral health state and the DMFT index, the subfactors of oral health behavior exerted a significant independent influence on subjective oral health status and the DMFT index. Conclusions : The findings of the study suggest that in order to promote the oral health of adults, preventive measures should be taken, and systematic oral health education should be provided. As there is an increase in the elderly population in Korea, the successful implementation of senior oral health plans and the development of oral health programs geared toward adults are both required.

• 국제지역연구
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• 제15권3호
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• pp.285-306
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• 2011

본 연구에서는 지역경제 관점에서 미국의 SCI(State Competitiveness Index)의 사례를 통해 지역경쟁력지표에 대해 살펴보고, 이들 지역경쟁력 지수와 지역성장 특성과 관계를 패널로짓분석을 통해 실증분석을 하였다. 특히 미국의 주를 대상으로 지역성장의 특성을 소득의 정태적 기준과 동태적 기준으로 구분하였다. 이에 대한 분석결과는 다음과 같다. 첫째 미국 주에서 지역경쟁력지수(SCI)가 전국평균이상인 지역이면서 소득의 정태적요인인 1인당 소득수준과 동태적 요인인 성장률이 전국평균 이상인 지역은 Alaska, Connecticut, Maryland, Massachusetts, Virginia, Washington, Wyoming으로 나타나, 이들 지역이 미국 주 중에서 지역경쟁력지수가 높으면서도 번성지역이라고 할 수 있다. 둘째, 지역성장의 소득수준과 지역경쟁력 지수와의 관계에 있어서는 인적자본, 과학기술, 비즈니스 인큐베이션, 개방성, 안정성, 환경정책 등의 변수들이 통계적 유의미했다. 셋째, 지역성장의 소득성장률과 지역경쟁력 지수와의 관계에 있어 인프라, 인적자본, 과학기술과 개방성 등이 통계적으로 유의미한 변수였다. 지식기반경제에 있어 지역소득수준과 성장률에 중요한 지역경쟁력 변수는 인적자본, 과학기술, 개방성이라고 할 수 있어 향후 한국의 지식기반경제에 있어 지역경쟁력을 강화하기 위해서는 지역경제차원에서 이들 지표에 대한 경쟁력 향상을 위한 정책이 중요할 것으로 판단된다.

• 한국정밀공학회지
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• 제16권12호
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• pp.152-160
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• 1999

The weld quality of $CO_2$ arc welding is closely related to the arc stability. As the characteristics of the arc are excessively complex and nonlinear, it is not easy to make the arc model as mathematical form and to control the arc state to be stabilized. This paper was aimed to estimate the arc stability and to control for stabilizing the arc state in short circuit metal transfer mode of $CO_2$ arc welding. For these purposes, the behaviors of arc stability was investigated at different welding conditions using Mita's arc stability index, and the fuzzy control algorithm which uses the arc stability index as control imput and the arc voltage as control output was developed. In the control of the arc stability, the experiments of two cases were performed; the case of setting an initial welding voltage arbitrarily, the case of the step change in workpiece shape. Obtained results were as follows; Mita's arc stability index was able to be estimated qualitatively in the case of using the inverter type welding power source and the control performance for stabilizing the arc status was excellent in the case of existing step change disturbance.

• Asian-Australasian Journal of Animal Sciences
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• 제19권5호
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• pp.713-719
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• 2006

The effect of dietary iodine and selenium supplementation, alone or in combination, on peripheral blood lymphocyte function was determined in laying hens. Eight-hundred-and-sixty-four New-Loman laying hens were randomly allotted into 12 dietary treatments with different inclusion levels of iodine (0, 0.1 and 0.2 mg/kg), selenium (0, 0.05, 0.1 and 0.2 mg/kg) or their combinations for 24 weeks. The lipopolysaccharide (LPS) stimulation index, concanavalin A (ConA) stimulation index, peroxide enzyme activity and phagocytosis to neutral red particles were tested. There were significant differences in LPS stimulation index, ConA stimulation index, peroxide enzyme activity and phagocytosis to neutral red particles in different iodine or selenium supplementation levels (p<0.05). The highest iodine and selenium supplementation both resulted in highest LPS-/ConA-stimulation indices (p<0.05). However, when iodine was lower than 0.2 mg/kg, the additional effect of different levels of selenium did not always result in significant differences in these indices. The results indicated that iodine and selenium may affect immunity in laying hens and, when the iodine level in the laying hen is lower than 0.2 mg/kg, a selenium allowance higher than 0.1 mg/kg may be necessary to improve immunity.