• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.6
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• pp.11-18
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• 2011

Accurate modal identification analysis is required to reasonably perform a seismic qualification of safety-related electric equipment installed in nuclear power plants (NPPs). This study evaluates a variation of the modal properties of an electric equipment cabinet structure in NPPs according to the excitation levels. For the study, an actual electric equipment cabinet was selected as a specimen and was dynamically tested by using a portable exciter in accordance with the level of input vibration energy. Tests were classified into two sets: with-door cases, and without-door cases. Frequency response functions were computed from the signals of the acceleration responses and input motions measured from the vibration tests. A polynomial curve fitting algorithm was used to extract the modal properties from the frequency response functions. This study reviews the variation of the modal properties according to the variation of the excitation levels. The results of the study show that the modal frequencies and the modal dampings of the object specimen varies nonlinearly according to the excitation level of the test motion. Attaching the door increases the modal damping of the cabinet.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1267-1272
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• 2007

In the case of the railway bridge, there are following the progress of works after the drainage method of a bridge surface - vibration proof rubber establishment, track gravel construction and rail construction etc. But these works are not enforced consecutively by the execution and economical reason. This is the reason of the long period of exposure after drainage execution. In many case, from the deterioration phenomenon by long term exposure of surface, there are a lot of occasions that do not keep primitive penetration depth waterproof primitive time. It is the most important that select the drainage method that have durability - it is not fallen in long-term exposure of surface. The major objective of this study is to deduce objective analysis result through examination about the Deterioration Restraining Agent method and to master KNOW-HOW of DRA drainage method. Through the study, minimize economical damage by frequent repair and reinforcement and present the reasonable standard of judgement fot drainage method of construction.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.360-367
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• 2020

In this study, the accumulation and distribution routes of microplastics in soil environment were examined, and their analytical methodologies were summarized. Density separation and removal process of inhibition materials were introduced for the separation of microplastics in soil and the basic principles and limitations of quantitative and qualitative analyses including pyrolysis gas chromatography mass spectrometry, µ-Raman spectrometry, fourier transform infrared spectrometry, and microscopes were investigated. Chemical extraction methods for the analysis of mediated hazardous substance (additives and sorbed matters) in microplastics were also discussed with focusing on in vitro bioaccessibility assay for the human oral exposure route. Based on the described methodologies for the analysis of microplastics in soil, it is expected that these methods enable to select appropriate analysis techniques in consideration of medium state, contamination level and sample quantity.

• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.73-82
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• 2002

The influence of bus stops near signalized intersections is one of the important factors which cannot be negligible in the analysis of the capacity of signalized intersections. Absence of consideration of bus bay can reduce capacity and increase the time that the stop of buses block other traveling vehicles. This influence is reflected by the bus blockage adjustment factor in KHCM, but the factor does not consider the course of each bus passing the intersection. Particularly, left turn buses have more influence on the capacity than the other buses and require the minimum length of the road for lane changes. All the existing criteria can apply only to arterial roads on which mostly traffic flows are continuous. And the criteria. which can determine the optimum location and the minimum distance between a signalized intersection and a bus bay, is not prepared and the related study is insufficient. Therefore, a theoretical formula is derived in this study being based on the theories which are avaliable to apply to the situation of signalized intersections.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.33-40
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• 2004

This study aims to provide guidelines for the selection of on-street parking spot on local streets considering conditions of surrounding area and characteristics of traffic generation. This guideline provides the method which determine required roadway width for planning and design of local streets. It is necessary to identify factors for the location selection analysis. This research team selects 12 case study areas to investigate traffic environment on the sites for this analysis. Most of factors which influence on-street parking are found to have a qualitative data format except traffic volume and pedestrian movement data. Quantification theory II which is known to be suitable for qualitative analysis has been applied to identify the meaningful variables for dependent variable. In addition, discriminant analysis has performed to verify the correlation for each variable with hit ratio. Road width, traffic volume, street traders and their heavy packages, and illegally parked vehicle are found to be most significant factors for selection of on-street parking location. Therefore, it is necessary to consider traffic volume generated from massive residential complex and traffic volume for outside and above-mentioned factors for installation of on-street parking facility in the case of new road construction or road width widen.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.471-477
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• 2010

In recently, IMO consider including an marine casualty factor when Port State Control Inspection evaluate.. This paper proposes an evaluation to Target Factor Values of Port State Control Inspections(PSCITFV) using absolute measurement. To this solve, therefore, this paper used the absolute measurement which is informed compensate the defect and the more rational and objective methode, checked the effectiveness to compare an result with absolute measurement and PSCITFV of Tokyo MOU using Wilcoxson test. Finally, rate change of PSC was investigated by an experiment which changed the values of evaluation factors. As a result, it was evaluation factors of high rate change that was detention, ship's age, casualty factors. Therefore, this factors have to a priority management to do for prevent of PSC.

• Journal of Korea Water Resources Association
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• v.30 no.1
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• pp.45-54
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• 1997

The correct estimation of the daily or hourly urban water demand is required for the efficient management and operation of the water supply facilities. The prediction of water supply demand are regression model and time series method, the optimum ARIMA (Auto Regressive Integrated Moving Average) model was sought for the daily urban water demand estimation in this paper. The data used for this study were obtained from the city of Kwangju Korea. The raw data used in this study were rearranged 15, 30, 60, 90 days for the purpose of analysis. The statistical analysis was applied to the data to obtain the ARIMA model. As a result, the parameters determining the ARIMA model was obtained. The accuracy of the model was 2% of water supply. The developed model was found to be useful for the practical operation and management of the water supply facilities.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.306-306
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• 2011

대상유역의 합리적인 홍수량 산정을 위해서는 풍부한 홍수자료를 바탕으로 직접적인 빈도해석을 적용하는 것이 가장 적정한 방법으로 알려져 있다. 하지만 국내의 대부분 유역은 관측된 홍수 자료가 제한적이고, 미계측 유역이므로 빈도해석을 통한 홍수량의 산정은 현실적으로 불가능한 실정이다. 이에 국내에서는 홍수량 산정에 대한 대안으로 강우-유출관계의 선형성을 가정한 집중형 강우-유출모형을 적용하고 있다. 하지만 집중형 강우-유출모형은 경험적인 공식에 의해 결정되는 수문매개변수의 비합리성 및 유역분할, 유역 하도추적의 구축방식에 따라 상이한 홍수량이 산정되는 문제점이 지적되고 있다. 따라서 최근에는 경험적이고 개념적인 집중형 유출모형을 지양하고, 격자체계를 기반으로 하고 있는 분포형 강우-유출모형의 연구가 활발히 진행되고 있는 상황이다. 본 연구의 목적은 남강 유역에서의 분포형 강우-유출모형 적용성 검증에 있다. 따라서 남강 유역 내에 발생한 4개의 호우사상을 선정한 후 강우 레이더 영상인 CAPPI영상 및 C-Max영상을 이용하여 면적강우량을 산정하였다. C-Max 영상을 이용하여 산정된 면적강우량은 지점강우를 이용한 면적강우량과 비교해 130%이상 과대 산정되는 경향을 나타낸 반면, CAPPI 영상을 이용하여 산정된 면적강우량은 10%이하의 오차를 나타내었다. 따라서 본 연구에서는 CAPPI 영상을 분포형 유출 모형인 VfloTM에 입력하여 유출을 모의 하였다. 모의된 유출곡선과 관측된 유출곡선을 비교 검토한 결과 80%이상의 높은 상관성을 나타낸 반면 첨두유출량 오차는 30%이상의 오차를 나타내었다. 하지만 강우보정기법인 G/R보정 기법을 적용한 후에는 첨두유출량 오차가 10%미만으로 감소하는 것으로 나타났다. 따라서 남강 유역에 분포형 유출모형을 적용하기 위해서는 다양한 강우 사상에 대한 지속적인 연구가 수행되어야 할 것으로 판단된다.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.1
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• pp.57-68
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• 2000

The purpose of this study is to find the most effective method of the coding methods by linking the attribute information with the digital map in Taegu metropolitan city. This study was also a precedent plan for street trees management information system and the coding schemes for street trees management information system could be summarized as follows; First, this study extracted 11 coding factors for expressing the position of street trees. Second, 11 coding schemes were made out of these coding factors and applied to the digital map(1:500). Third, two methods of 11 coding schemes were selected for street trees management information system of Taegu metropolitan city. The one was the method which applied serial numbers according to the block name. The other was the method utilizing the concept of 'dynamic segment'. Finally, this study will be the first step for the computerization and management of the street trees information and this computerized data will do for the management efficiency of the street trees on internet.

• Journal of the Korean Society for information Management
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• v.18 no.2
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• pp.31-56
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• 2001

The number of websites in Korea is increasing rapidly as demonstrated by more than 510,000websites registered under the ".kr" domain as of the end of December 2000. In order to effectively copewith the deluge of web information and maintain ready access to useful information on the web,utilization and management of web information through websites that have been evaluated and ratedfavorably is becoming increasingly important. As websites now increasingly provide industry-specificinformation, information managers are now finding it essential to meet their specific information needsthrough separation and ranking of useful information from the rest.However, evaluation of industry-specific information requires industry-specific expertise as well asgeneral website evaluation tools. This paper develops a website evaluation model and attempts to rankindustry-specific websites through case studies of previous website evaluation and consultation withexperts in specific industries. Based on the model developed, this paper selects 100 outstanding websitesin 10 areas of construction industry. The research also hypothesizes that, with appropriate modifications,the rating models used for the construction industry can also be applied to other industries for moreefficient information management.e efficient information management.