• Earthquakes and Structures
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• 제13권4호
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• pp.337-351
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• 2017

In the present study a capacity spectrum method based on constant ductility inelastic spectra to estimate the seismic performance of structures equipped with elastic viscous dampers is presented. As the definition of the structures' effective damping, due to the damping system, is necessary, an alternative method to specify the effective damping ratio ${\xi}eff$ is presented. Moreover, damping reduction factors (B) are introduced to generate high damping elastic demand spectra. Given the elastic spectra for damping ratio ${\xi}eff$, the performance point of the structure can be obtained by relationships that relate the strength demand reduction factor (R) with the ductility demand factor (${\mu}$). As such expressions that link the above quantities, known as R - ${\mu}$ - Τ relationships, for different damping levels are presented. Moreover, corrective factors (Bv) for the pseudo-velocity spectra calculation are reported for different levels of damping and ductility in order to calculate with accuracy the values of the viscous dampers velocities. Finally, to evaluate the results of the proposed method, the whole process is applied to a four-storey reinforced concrete frame structure and to a six-storey steel structure, both equipped with elastic viscous dampers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.196-198
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• 2003

The low load power factor causes various problems such as the increase of the power loss and the voltage instability. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power troublesome, from which the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is derived and its effects in supplying the reactive power and enhancing the load power factor are analyzed in a small-scale power system. The load power factor sensitivity of the generation cost is applied for determining the locations and capacities of reactive power compensation devices. It is shown that the generation cost can be reduced and the system power factor can be enhanced effectively using the load power factor sensitivity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.153-155
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• 2004

Various problems such as the increase of the power loss and the voltage instability may often occur in the case of low load power factor. The demand of reactive power increases continuously with the growth of active power and the restructuring of electric power companies makes the integrated management of ractive power a troublesome problem, so that the systematic control of load power factor is required. In this paper, the load power factor sensitivity of the generation cost is used for determining the locations of reactive power compensation devices effectively and for enhancing the load power factor appropriately. In addition, the integrated costs are used for determining the value of the load power factor from the point of view of the economic operation. It is shown through the application to a large-scale power system that the system power factor can be enhanced effectively and appropriately using the load power factor sensitivity and integrated costs.

• 한국산학기술학회논문지
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• 제20권3호
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• pp.617-631
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• 2019

본 4단계 교통수요예측모형의 통행분포단계에서 중력모형이 가장 일반적으로 활용하고 있다. 본 연구는 중력모형변수(통행시간, 통행비용 등)의 가변적인 한계를 보완하기 위해 접근성 속성을 단일 마찰인자로서 표현할 수 있는 보다 현실적이고 장래 활용이 용이한 신규 마찰인자를 개발하는데 그 목적이 있다. 이에 신규 마찰인자 도출을 위해 도시공간구조의 특성을 정량화할 수 있는 공간구문론(space syntax)을 활용하여 Link 단위 통합도를 도출 후 통행시간, 통행거리 관계를 이용해 일종의 대리변수로서의 신규 마찰인자를 도출하였다. 대수전환을 통한 마찰인자별 정산결과, 기존 마찰인자(최단거리, 통행시간) 대비 유사하거나 더 높은 수준을 보이는 것으로 분석되었다. 다양한, 검증지표를 활용하여 기존 마찰인자와의 비교시, 전체적으로는 기존 마찰인자와 유사하지만, 단거리 구간 및 장거리 구간에서 설명력이 뛰어난 것으로 분석되었다. 따라서, 기존 최단거리의 한계에서 벗어나 접근성을 보완할 수 있는 통합도 지표를 이용하여 신규마찰인자 도출 및 적용이 가능하고, 장래 활용성에서 좀 더 장점을 갖는 것으로 판단된다.

• 한국문헌정보학회지
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• 제47권3호
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• pp.181-205
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• 2013

이 연구는 대학도서관 사서들이 업무수행 과정에서 받고 있는 직무스트레스를 보다 정확하게 측정할 수 있는 척도를 개발하고자, 실증연구를 통하여 기존의 국내 외 대표적 직무스트레스 척도를 분석하여 종합하고, 질적 연구방법 중 심층면접법을 도입하여 대학도서관 사서가 가지고 있는 특징적인 스트레스 요인을 추적하였다. 또한 두 척도를 종합한 직무스트레스 척도의 신뢰도와 타당도에 대한 분석을 실행하였다. 그 결과 '동료관계 갈등요인', '상하관계 갈등요인', '업무보상 평가요인', '감정노동 요인', '물리적 환경요인', '고용안정성', '심리적 직무요구요인', '의사결정 및 책임요인', '업무복잡성 요인', '업무경계 갈등요인', 그리고 '신체적 직무요구요인' 등 11개 요인, 46개 문항으로 구성된 사서를 위한 직무스트레스 척도가 개발되었다.

• International Journal of Human Ecology
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• 제4권2호
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• pp.77-87
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• 2003

This paper tried to construct statistical and econometric models on the basis of economic theory in order to discuss the issue of statistical efficiency and unbiasedness including the sample selection bias correcting problem. Comparative analytical tool were one stage Tobit of Maximum Likelihood estimation and Heckman's two-step Tobit of Ordinary Least Squares. The results showed that the adequacy of model for the analysis on demand and choice, we believe that there is no big difference in explanatory variables between the first selection model and the second linear probability model. Since the Lambda, the self- selectivity correction factor, in the Type II Tobit is not statistically significant, there is no self-selectivity in the Type II Tobit model, indicating that Type I Tobit model would give us better explanation in the demand for and choice which is less complicated statistical method rather than type II model.

• 한국경영과학회지
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• 제31권3호
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• pp.27-40
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• 2006

Today's customer demands in supply chains tend to change quickly, variously even in a short time Interval. The uncertainties of customer demands make it difficult for supply chains to achieve efficient inventory replenishment, resulting in loosing sales opportunity or keeping excessive chain wide inventories. Un this paper, we propose an adaptive vendor managed inventory (VMI) model for a two-echelon supply chain with non-stationary customer demands using the action-reward learning method. The Purpose of this model is to decrease the inventory cost adaptively. The control Parameter, a compensation factor, is designed to adaptively change as customer demand pattern changes. A simulation-based experiment was performed to compare the performance of the adaptive VMI model.

• 산업기술연구
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• 제24권A호
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• pp.185-194
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• 2004

To evaluate seismic performance of reinforced concrete piers two procedures for capacity spectrum method are presented. The capacity spectrum procedures include the reduction factor-ductility-period($R_{\mu}-{\mu}-T$)relationship in order to construct the inelastic demand spectra from the elastic demand spectra. Application of the procedures are illustrated by example analysis. Maximum displacements estimated by the procedures are compared to those by inelastic time history analysis for several artificial earthquakes. The results show that the maximum displacements estimated by the procedures are, on overall, smaller than those by the inelastic time history analysis.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 춘계학술발표대회
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• pp.1075-1078
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• 2005

The Global IT revolution is growing rapidly. Government and business have to be ready to meet the increased demand for effective and secure online services. With the E-Government practicing, day-by-day the public demand is also increasing simultaneously. Now this present moment, one of important research part is secure E-Voting for E-Government service, but for this important factor or Government Issue, it needs information privacy for secure information transaction of citizen’s opinions and secure authentication. This paper has analyzed several approaches E-voting protocols, those are implemented with many digital signature mechanism and maintained many types of cryptographic rules, which are main factor for information privacy. In this paper we have discussed them with a view to voter anonymity and protection from manipulations. The paper then developed an algorithm designed to guarantee anonymity of the voter and to avoid the risk of manipulation of votes. In this paper the proposed algorithm is based upon the strict separation of voter’s registration and submission of votes, which means that certain information has to be stored on a secure storage media.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.347-348
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• 2010

The purpose of this study lies in presenting a methodology to estimate the amount of water to be used in the future by grasping the state of water use in real time based on a statistical analysis using water unit factor application of urban water demand of existing housing, education facilities, and industrial water as well as sensing data by water type. The results of the study would provide in real time the state of water use per water type and the amount of water to be consumed in the future in order to provide basic data for decision-making when planning and managing water facilities based on GIS at times water lacks.