• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.414-422
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• 2006

Deterministic techniques have been applied in power system planning for many years and there is a growing interest in combining these techniques with probabilistic considerations to assess the increased system stress due to the restructured electricity environment. The overall reliability framework proposed in this paper incorporates the deterministic N-1 criterion in a probabilistic framework, and results in the joint inclusion of both adequacy and security considerations in system planning. The combined framework is achieved using system well-being analysis and traditional adequacy assessment. System well-being analysis is used to quantify the degree of N-1 security and N-1 insecurity in terms of probabilities and frequencies. Traditional adequacy assessment is Incorporated to quantify the magnitude of the severity and consequences associated with system failure. The concepts are illustrated by application to two test systems. The results based on the overall reliability analysis framework indicate that adequacy indices are adversely affected by a generation deficient environment and security indices are adversely affected by a transmission deficient environment. The combined adequacy and security framework presented in this paper can assist system planners to realize the overall benefits associated with system modifications based on the degree of adequacy and security, and therefore facilitate the decision making process.

• 한국물환경학회지
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• 제31권4호
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• pp.407-417
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• 2015

Soil loss is one of the significant disasters which have threatened human community and ecosystem. Particularly, Korea has high vulnerability of soil loss because rainfall is concentrated during summer and mountainous regions take more than 70% of total land resources. Accordingly, the sediment control management plan are required to prevent the loss of soil resources and to improve water quality in the receiving waterbodies. In this regard, the objectives of this study are 1) to quantify the effect of the Vegetative Filter Strip (VFS) on sediment runoff reduction and 2) to analyze the relationship of rainfall intensity and sediment runoff. For this, SATEEC and VFSMOD were used to estimate sediment runoff according to rainfall intensity and to quantify the effect of VFS on sediment runoff reduction, respectively. In this study, the VFS has higher impact on sediment reduction for lower maximum rainfall intensity, which means that the maximum rainfall intensity is one of significant factors to control sediment runoff. Also, the sediment with VFS considered was highly correlated with maximum rainfall intensity. For these results, this study will contribute to extend the applicability of VFS in establishing eco-friendly sediment control plans.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권5호
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• pp.338-347
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• 2005

A computer-based low back muscle evaluation system was designed to simultaneously acquire, process, display, quantify, and correlate electromyographic(EMG) activity with muscle force, and range of motion(ROM) in the lumbar muscle of human. This integrated multi-channel system was designed around notebook PC. Each channel consisted of a time and frequency domain block, and T-F(time-frequency) domain block. The captured data in each channel was used to display and Quantify : raw EMG, histogram, zero crossing, turn, RMS(root mean square), variance, mean, power spectrum, median frequency, mean frequency, wavelet transform, Wigner-Ville distribution, Choi-Williams distribution, and Cohen-Posch distribution. To evaluate the performance of the designed system, the static and dynamic contraction experiments from lumbar(waist) level of human were done. The experiment performed in five subjects, and various parameters were tested and compared. This system could equally well be modified to allow acquisition, processing, and analysis of EMG signals in other studies and applications.

• 한국농공학회지
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• 제39권3호
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• pp.115-127
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• 1997

Nonpoint source (NPS) pollution from small watersheds has recently been brought into attention as a potential pollutant to streams and tnbutaries, as majority of them are experiencing water quality degradation. This necessiates the quantification of NPS loadings from agricultural and forested lands. And this study attempts to quantify daily loadings from forested and farm lands using hydrologic and water quality monitoring. The hydrologic monitoring program consists of five water level gauging stations along creeks and stream at the Banweol reservoir watershed having 1220 hectare in size. Water sam pies were taken and analyzeel periodically at the streamf low gaging sites and tributaries. Soil samples were also taken and the chemical constitutes analyzed. The primary results indicate that the major sources of pollution were small villages and dairy farms on the watersheds, constituting two-third of total nutrient loadings to the reservoir. However, the loadings from paddies and upland areas may cause a problem to the water quality of the reservoir and stream as the measured levels of total nitrogen and phosporus are not low enough to ignore. Further studies are needed to quantify the effects of landuses and treatments at a watershed scale.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1998년도 학술발표회 논문집
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• pp.7-13
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• 1998

본 연구에서는 공간적으로 분포되어 있는 연강우량 자료를 이용한 지역 기상학 적인 가뭄을 정의하고 해석하는 모형을 제시한다. 비선형, 비매변수법에 기초한 공간 해석 신경망 (Spatial Analysis Neural Network:SANN)모형을 이용하여, 각 년에 대하여 공간의 임의 점에 서 의 극심, 심, 경심, 및 비 가뭄 확률을 전 대상 지역에 대하여 산출을 통하여 가뭄확률도를 작성 하며, Bayesian 가뭄 심도 지수 (BDSI)를 통하여 전 대상 지역을 가장 적절하게 극심, 심, 경심, 미 가뭄 지역으로 분류하는 방법을 제시한다. 또한, 각 년의 대표적인 가뭄의 형태를 제시 하여 줄 수 있는 지역 가뭄확률과 지역 가뭄 확률 지수를 소개한다. 이 모든 시공간의 가뭄 해석의 방법 은 실제로 우리나라(남한) 전역에 대하여 실시하여, 과거 1967년부터 1996년 까지 의 공간적이고 시간적인 가뭄의 발생 현황과 그 특징을 조사한다. 이는 우리나라 장기 수자원 개발 및 유역 관 리를 더욱 정량적인 가뭄정보에 의해 수행하게하여 줄 수 있을 것이다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1798-1806
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• 2018

When a contingency occurs in a large transmission route in a power system, it can generate various instabilities that may lead to a power system blackout. In particular, transient instability in a power system needs to be immediately addressed, and preventive measures should be in place prior to fault occurrence. Measures to achieve transient stability include system reinforcement, power generation restriction, and generator tripping. Because the interpretation of transient stability is a time domain simulation, it is difficult to determine the efficacy of proposed countermeasures using only simple simulation results. Therefore, several methods to quantify transient stability have been introduced. Among them, the single machine equivalent (SIME) method based on the equal area criterion (EAC) can quantify the degree of instability by calculating the residual acceleration energy of a generator. However, method for generator tripping effect evaluation does not have been established. In this study, we propose a method to evaluate the effect of generator tripping on transient stability that is based on the SIME method. For this purpose, the measures that reflect generator tripping in the SIME calculation are reviewed. Simulation results obtained by applying the proposed method to the IEEE 39-bus system and KEPCO system are then presented.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.41-44
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• 2008

본 연구의 목적은, X선조영촬영을 이용한 콘크리트강도의 평가 및 콘크리트열화의 수치화를 수행하는 것이다. 콘크리트강도를 추정하기 위하여, 물-시멘트비가 서로 다른 콘크리트를 제작하여, X선투과선량과 콘크리트강도의 관계를 구하였다. 이 실험에는 콘크리트 외에 몰탈, Non-AE 콘크리트를 이용한 실험도 수행하였다. 또한, 동결융해작용을 가해 상대동탄성계수를 변화시킨 공시체에 대하여, 열화의 수치화를 수행하였다. 실험의 결과, X선조영촬영법을 사용하면, 투과선변화량이 구해지므로, 콘크리트강도의 추정과 열화의 수치화가 가능하다는 것을 알았다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권3호
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• pp.21-29
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• 2001

양이온성 계면활성제인 HDTMA를 이용하여 치환시킨 유기 벤토나이트의 중금속 흡착능을 알아보았다. 카드뮴과 납의 흡착량은 pH와 흡착제 대 용액 비가 증가함에 따라 증가하였다. 이 실험을 통해 적정 pH 범위와 흡착제 대 용액 비를 결정하였다. 유기 벤토나이로의 중금속 흡착은 벤토나이트에 비해 약간 감소하였으며, 두 가지 중금속이 함께 존재하는 경우 경쟁에 의해 흡착량은 더 감소하였다. 유기 벤토나이트의 경우 카드뮴에 비해 납의 흡착 감소량은 더 두드러지게 나타났다. 이러한 흡착 mechanism을 hard-soft-acid-base (HSAB) 원리를 사용하여 설명하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.208-214
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• 2000

Reduction of structure-borne noise of the compartment in a car is an important task in automotive engineering. Transfer path analysis using vibroacoustic reciprocity technique or multiple path decomposition method has generally been used for structure-borne noise path analysis. These methods are useful in solving particular problem but do not quantify the effectiveness of vibration isolation of each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow has been used for a simple isolation system or a laboratory based isolation system. It is often difficult to apply the vibrational power flow technique to the complex isolation system like a car. In this paper, a simple equation is derived for calculation of the vibrational power flow of an isolation system with multiple isolators such as a car. It is successfully applied to not only quantifying the relative contributions of eighteen isolators but also reducing structure-borne noise of a passenger car. According to the results, the main contributor of eighteen isolators is the rear roll mount of an engine. The reduced structure-borne noise level is about 5dBA.

• Advances in concrete construction
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• 제10권3호
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• pp.271-278
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• 2020

Quantifying the amount of damage of structures under earthquakes is an interesting issue that researchers have attended on and have presented some damage indices. Whereas a lot of damage indices have been introduced based on nonlinear dynamic analysis, computational effort, the calculus complicacy and time-consuming of this analysis are the main drawbacks to widespread use of these indices. The objective of this study is to quantify the damage of Shear Wall Reinforced Concrete Frames (SWRCFs) based on pushover analysis as a procedure that can reflect the behavior of structures from elastic to collapse. For this purpose, firstly, several SWRCFs are designed and the capacity spectrum of each one is achieved via pushover analysis. After that, the static damage indices of the designed frames are obtained. Then, nonlinear dynamic analyses are performed on these frames and the Park and Ang damage index as the basis damage criterion is achieved. Afterward, some relations are presented to predict the dynamic damage of these frames via pushover analysis. Eventually, to confirm the validity of the proposed relations, the values of Park and Ang damage index of three new SWRCFs are acquired once utilizing nonlinear dynamic analysis and again applying the introduced relations. Outcomes prove the validity of some presented damage indices.