• Structural Engineering and Mechanics
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• 제10권6호
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• pp.517-532
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• 2000

A direct output feedback control scheme was recently proposed by the authors for single-story building structures resting on flexible soil body. In this paper, the control scheme is extended to mitigate the seismic responses of multi-story buildings. Soil-structure interaction is taken into account in two parts: input at the soil-structure interface/foundation and control algorithm. The former reflects the effect on ground motions and is monitored in real time with accelerometers at foundation. The latter includes the effect on the dynamic characteristics of structures, which is formulated by modifying the classical linear quadratic regulator based on the fundamental mode shape of the soil-structure system. Numerical result on the study of a $\frac{1}{4}$-scale three-story structure, supported by a viscoelastic half-space of soil mass, have demonstrated that the proposed algorithm is robust and very effective in suppressing the earthquake-induced vibration in building structures even supported on a flexible soil mass. Parametric studies are performed to understand how soil damping and flexibility affect the effectiveness of active tendon control. The selection of weighting matrix and effect of soil property uncertainty are investigated in detail for practical applications.

• 산업경영시스템학회지
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• 제42권2호
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• pp.62-68
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• 2019

The growth and employment effects of R&D investment were analyzed according to business size, export value and manufacturing sectors so as to suggest improvement directions for effective industry policies. The effect of R&D investment was considered simultaneously from the two perspectives of growth and employment effect, and the causality analysis was carried out by using a path analysis. The result of the path analysis confirmed significant differences in the growth effect of R&D investment depending on business size. However, the effect of increasing employment was difficult to obtain statistically significant results for any various combinations of business size and export value. This is a mixture of directions for the effects of R&D investment on employment, which could be due to the failure to consider appropriate time lags between investment and effect. Efficiency analysis by industry sectors confirmed significant differences in efficiency depending on business size, but differences depending on export value were difficult to identify. In order to derive improvement policy by industry sector according to business size and export value, the direction of selective support policy and universal support policy was derived for six industry groups by combining the return to scale in the efficiency analysis and R&D concentration. Hirschman-Herfindahl index is used for calculating R&D concentration.

• 한국터널지하공간학회 논문집
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• 제8권2호
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• pp.151-163
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• 2006

대단면 터널에서 시공되는 사전보강공법에 의한 보강영역의 보강효과를 수치해석적으로 모델링하기 위한 다양한 방법이 제시되고 있지만 실무자들은 공학적인 방법보다는 경험적인 방법과 문헌을 참고하여 설계를 수행하고 있다. 따라서 본 연구에서는 상용 프로그램에서 직접적으로 적용할 수 있는 사전보강 영역의 물성치 결정에 있어서 거시적 접근법의 개념을 기반으로 미시적 접근법을 적용한 등가 물성치를 결정하는 기법을 제시하고 3차원 수치해석을 통한 실제모델 해석결과와 다른 여러 미시적 접근법들과의 비교 분석을 수행하여 타당한 보강영역 물성치 결정기법을 제시하였다. 해석 결과 구근과 강관의 병렬연결 강성이 원지반과 직렬로 연결되는 사전보강영역의 직병렬 강성 시스템과, 구근과 강관의 직렬 강성 시스템이 실해와 가장 근사한 변위를 예측하였으나 후자의 경우 그 모델링 과정이 복잡하므로 본 연구에서는 간편법으로써 직병렬 강성 시스템을 제안한다. 직병렬 강성 시스템은 천단변위에 대해 풍화암 지반에서는 약간 안전측으로, 내공변위와 지표면 변위에 대해서는 정밀모델의 결과와 거의 동일하게 거동하는 것으로 분석되었으며 풍화토와 풍화암 지반에서 동일한 변위 경향성을 나타낸다. 본 연구에서 제시된 사전보강영역의 직병렬 강성 시스템은 실제모델로 대표되는 보강지반의 거동 메카니즘을 효과적으로 나타내는 것으로 분석된다.

• 한국의료질향상학회지
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• 제5권2호
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• pp.202-215
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• 1998

Purpose : To shorten processing time for variety of medical affairs of the patient at the outpatient clinic of a big hospital is very important to qualify medical care of the patient. Therefore, patient's waiting time for drug delivery after doctor's prescription is often utilized as a strong tool to evaluate patient satisfaction with a medical care provided. We performed this study to investigate factors influencing patient satisfaction related with waiting time for drug delivery. Methods : The data were collected from July 21 to August 12, 1998. A total 535 patients or their families who visited outpatient clinics of Inha University Hospital were subjected to evaluate the drug delivery time and the level of their satisfaction related, which were compared with those objectively evaluated by Quality Improvement Team. The reliability of the scale was tested with Cronbach's alpha, and the data were analyzed using frequency, t-test, ANOVA, correlation analysis and multiple regression. Results : The mean drug delivery time subjectively evaluated by the patient (16.1 13.0 min) was longer than that objectively evaluated (10.9 7.6 min) by 5.2 min. Drug delivery time objectively evaluated was influenced by the prescription contents, total amount or type of drug dispensed, etc, as expected. The time discrepancy between two evaluations was influenced by several causative factors. One of those proved to be a patient's late response to the information from the pharmacy which the drug is ready to deliver. Interestingly, this discrepancy was found to be more prominent especially when waiting place for drug delivery was not less crowded. Other factors, pharmaceutical counseling at the pharmacy, emotional status or behavior of a patient while he waits for the medicine, were also found to influence the time subjectively evaluated. Regarding the degree of patient satisfaction with the drug delivery, majority of patients accepted drug delivery time with less than 10 min. It was also found to be influenced by emotional status of the patient as well as kindness or activity of pharmaceutical counselor. Conclusion : The results show that, besides prescription contents, behavior pattern or emotional status of a patient, environment of the waiting place, and quality of pharmaceutical counseling at the pharmacy, may influence the patient's subjective evaluation of waiting time for drug delivery and his satisfaction related with the service in the big hospital. In order to improve patient satisfaction related with waiting time for drug delivery, it will be cost effective to qualify pharmaceutical counseling and information system at the drug delivery site or waiting place rather than to shorten the real processing time within the pharmacy.

• 대한원격탐사학회지
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• 제34권6_2호
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• pp.1229-1238
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• 2018

본 연구에서는 위성영상 기반의 북극의 해빙 농도 시계열 데이터를 이용하여 베링해의 해빙 상태가 척치해 해빙 농도 변화의 전조로서 작용할 수 있는지를 실험하였다. 해빙 농도 자료는 1982년부터 2017년의 36년간의 월평균 시계열 데이터로 이뤄져 있으며, 베링해의 해빙 농도와 척치해 해빙 농도 사이의 관계성을 전송 엔트로피 측정을 통해 분석하였다. 전송 엔트로피는 두 개의 확률변수 또는 신호 간의 비선형적 연관성을 파악하게 해주는 동시에 변수 사이의 시간 간격 조절을 통해 인과관계를 추정할 수 있는 측정이다. 해빙 농도를 대상으로 한 측정 결과, 베링해의 과거 3, 5, 6개월 전의 해빙 농도값이 척치해 해빙의 변화에 관련되어 있음을 알 수 있었다. 특히, 베링해의 해빙 농도값이 극소를 나타냈을 때, 5개월 후의 척치해의 해빙 농도는 감소될 확률이 약 70%로 나타났다. 이는 태평양에서 베링해협을 통해 북극해로 유입되는 해류가 베링해의 해빙 농도를 감소시킨 후 해협을 통해 척치해로 이동하여 해빙을 녹이는 과정에 비롯한 것으로 사료된다. 향후 위성데이터에 정보 이론으로 접근하는 이 연구를 더 발전시켜 어떤 시점과 시간적 스케일로 특이 패턴이 발생하는지 조사하고 그 기간에 관련된 해양-대기의 패턴 또는 사건들을 분석하여, 떨어진 두 지역의 해빙 농도 상태에 내재된 연관성에 대한 심층적 이해가 가능할 것이다.

• 상하수도학회지
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• 제21권1호
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• pp.13-25
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• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.

• 대기
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• 제25권4호
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• pp.623-637
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• 2015

The accurate analysis of water vapor in initial of numerical weather prediction (NWP) model is required as one of the necessary conditions for the improvement of heavy rainfall prediction and reduction of spin-up time on a very-short-range forecast. To study this effect, the impact of a ground-based Global Positioning System (GPS)-Precipitable Water Vapor (PWV) on very-short-range forecast are examined. Data assimilation experiments of GPS-PWV data from 19 sites over the Korean Peninsula were conducted with Advanced Storm-scale Analysis and Prediction System (ASAPS) based on the Korea Meteorological Administration's Korea Local Analysis and Prediction System (KLAPS) included "Hot Start" as very-short-range forecast system. The GPS total water vapor was used as constraint for integrated water vapor in a variational humidity analysis in KLAPS. Two simulations of heavy rainfall events show that the precipitation forecast have improved in terms of ETS score compared to the simulation without GPS-PWV data. In the first case, the ETS for 0.5 mm of rainfall accumulated during 3 hrs over the Seoul-Gyeonggi area shows an improvement of 0.059 for initial forecast time. In other cases, the ETS improved 0.082 for late forecast time. According to a qualitative analysis, the assimilation of GPS-PWV improved on the intensity of precipitation in the strong rain band, and reduced overestimated small amounts of precipitation on the out of rain band. In the case of heavy rainfall during the rainy season in Gyeonggi province, 8 mm accompanied by the typhoon in the case was shown to increase to 15 mm of precipitation in the southern metropolitan area. The GPS-PWV assimilation was extremely beneficial to improving the initial moisture analysis and heavy rainfall forecast within 3 hrs. The GPS-PWV data on variational data assimilation have provided more useful information to improve the predictability of precipitation for very short range forecasts.

• 지능정보연구
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• 제25권2호
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• pp.77-97
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• 2019

제 4차 산업혁명의 초연결 환경에서 발생하는 많은 양의 데이터는 제 4차 산업혁명을 기존의 생산 환경과 구분지어 주는 주요한 요소이다. 이러한 환경은 데이터를 필요로 하는 동시에 데이터를 생산하는 양면적인 특징을 가진다. 때문에 앞으로의 정보 시스템은 기존의 정보시스템보다 양적인 측면에서 더 많은 데이터를 처리해야 하며, 질적인 측면에서는 많은 데이터 중 사용자의 목적에 부합하는 목표 데이터만을 추출하는 능력이 요구된다. 작은 규모의 정보 시스템에서는 사람이 그 시스템을 정확히 이해하고 필요한 정보를 획득하는 것이 가능하지만, 시스템에 대해 정확한 이해가 어려워진 다양하고 복잡한 시스템에서는 원하는 정보를 획득하는 것이 점점 더 어려워진다. 이러한 문제는 데이터를 사람뿐 아니라 컴퓨터가 이해할 수 있는 온톨로지로 표현하여 다양한 정보처리가 가능하도록 하는 시맨틱 웹(Semantic Web) 구축이 해결책이 될 수 있다. 군에서도 현재 대부분의 업무가 정보 시스템을 통해 이루어지고 있는데, 정보의 입력이나 가공 등 단순처리 중심으로 구축된 기존 시스템이 점점 더 많은 양의 데이터를 포함하게 되면서 시스템을 쉽게 활용하기 위한 노력이 필요한 상황이다. 본 연구에서는 온톨로지를 통한 지능형 의사결정지원시스템의 예로 온톨로지 기반 군수상황관리체계를 제안하고자 한다. 온톨로지 기반 군수상황관리체계는 기존의 군수정보체계의 복잡한 정보를 직관적으로 보여주기 위해 구축된 군수상황관리체계를 온톨로지를 통해 구축하였으며, 성과기반군수지원 계약관리, 부품사전 등의 유용한 기능을 추가 식별하여 온톨로지에 포함하였다. 또한 구축된 온톨로지가 의사결정지원에 활용할 수 있는지를 확인하기 위해 시맨틱 웹 기술을 통해 기본적인 질의응답은 물론 추론 및 함수를 통한 분석기능을 구현하였다.

• 생태와환경
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• 제44권4호
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• pp.347-357
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• 2011

2010년 고온기 (여름~가을) 동안 수체 크기와 수질이 서로 다른 부영양 하천 (경안천, 제천천) 및 저수지 (인경 저수지, 중앙저수지)의 유기물 제어를 목적으로 기 개발된 식물- 광물 혼합제(PMC)를 동일한 농도($0.05\;mg\;L^{-1}$)로 각각 처리하고 수질, 플랑크톤 변화를 조사하였다. 또한 남조 Microcystis aeruginosa 밀도가 높았던 중앙저수지에서는 동시에 조류 독소 microcystin-LR 변화를 각각 조사하였다. 실험은 수체의 크기를 고려하여 인경저수지를 제외한 나머지 장소에서는 실험용 메조코즘을 설치하였다. 실험결과, 강우와 어류에 의한 교란이 심했던 경안천에서는 모든 항목에 대하여 45% 이하의 낮은 수질개선능을 보인 반면, 수체가 안정되고 남조류 밀도가 높았던 수체에서는 SS (70~81%), TP (75~91%), BOD (65~91%), Chl-a (88~98%), 식물플랑크톤 (84~92%), 동물플랑크톤 (68~88%) 등에 높은 수질개선효과를 보였다. 한편 PMC 처리 후 조체성에 비해 용존성 독소(96%)가 현저하게 감소하여 유해물질 제어 가능성을 나타냈다. 따라서 기 개발된 PMC는 수체 교란이 적고 남조류가 우점하는 수체내 유기물 제어에 적합한 것으로 판단되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.45-48
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• 2009

This study evaluated the influence of temperature on the PV module surface on power output characteristics, especially for an amorphous transparent thin-film PV module which was applied to a full-scale mock-up model as building integrated photovoltaic system. The tested mock-up consisted of various slopes of PV module, facing to the south. The annual average temperature of the module installed with the slope of $30^{\circ}$ revealed $43.1^{\circ}C$, resulting in $7^{\circ}C$ higher than that measured in PV modules with the slope of $0^{\circ}$and $90^{\circ}$ did. This $30^{\circ}$ inclined PV module also showed the highest power output of 28.5W (measured at 2 PM) than other two modules having the power output of 20.4W and 14.9W in the same time for $0^{\circ}$ and $90^{\circ}$ in the slope, respectively. In case of the $30^{\circ}$ inclined PV module, it exhibited very uniform distribution of power output generation even under the higher temperature on the module surface. Consequently, the surface temperature of the PV module analyzed in this study resulted in 0.22% reduction in power output in every $1^{\circ}C$ increase of the module surface temperature.