• Title/Summary/Keyword: Model Efficiency

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A Study on Value Evaluation of Smart Intermodal-Transfer Service (복합환승센터 스마트환승정보서비스에 대한 이용자 가치 추정 연구)

  • Lim, Jung-Sil;Kim, Sung-Eun;Lee, Chunl-Ki
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.11 no.4
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    • pp.19-33
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    • 2012
  • Ministry of Land, Transport and Maritime Affairs prepared the method to update traffic connection system by amending "National Transport System Efficiency Act(hereinafter Act)". The key is a development of Intermodal Transfer Center. The law and guideline related with Intermodal Transfer Center requires the installation and operation of transfer information guide facility to improve user's convenience. However, there are no sufficient studies that can be used as references for the method to construct transfer support information system related with user's preference. The study performed the research about user's service satisfaction in relation with transfer support information service, which was embodied in model operation process, on the basis of transfer support information system of Intermodal Transfer Center applied to Gimpo Airport. The analysis result about service preference, importance of each supplied information, service satisfaction and consideration for service embodiment can be used as a guideline to embody the user information service of Intermodal Transfer Center. In addition, through CVM, the study estimated and proposed the service valuation of smart intermodal transfer service that provides customized information to cope with user's situation and traffic means operation status among transfer support information service. It is determined that the study will measure the benefit of Intermodal Transfer Center user by using monetary value when smart intermodal transfer service is supplied and provide the ground to expand high-tech transfer information service with high usefulness and convenience.

A Study of IT Outsourcing Model for a Public Institution (공공기관의 IT 아웃소싱 모델 연구)

  • Oh, Yeon-Chil;Park, So-Ah;Lee, Young-Seok;Yang, Hae-Kwon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.10
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    • pp.1723-1730
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    • 2008
  • The national IT outsourcing is actively achieved centering around the manufacturing enterprise and financial institution. The If outsourcing of the public institution is generalized. The IT development and operation management task are the field in which first an outsourcing is introduced due to a factor including the technological change, the efper increase in demand, and etc. Particularly, the core business of the public institution is the public service. Therefore, the core business of the public institution can concentrate on the core business and by drastically outsourcing the etc task ran improve an efficiency. Therefore, as to the IT outsourcing, the innovative method that can enhance the quality of the public service can become. In this paper, We analyze how the Supply Administration introducing the service level agreement (SLA: Service Level Agreement) and the problem that the Samsung SDS is faced with were solved. And the practical affairs guide-line for managing elements which can minimize trial and error and successfully implement the IT outsourcing is presented.

Gender-independent efficacy of mesenchymal stem cell therapy in sex hormone-deficient bone loss via immunosuppression and resident stem cell recovery

  • Sui, Bing-Dong;Chen, Ji;Zhang, Xin-Yi;He, Tao;Zhao, Pan;Zheng, Chen-Xi;Li, Meng;Hu, Cheng-Hu;Jin, Yan
    • Experimental and Molecular Medicine
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    • v.50 no.12
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    • pp.12.1-12.14
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    • 2018
  • Osteoporosis develops with high prevalence in both postmenopausal women and hypogonadal men. Osteoporosis results in significant morbidity, but no cure has been established. Mesenchymal stem cells (MSCs) critically contribute to bone homeostasis and possess potent immunomodulatory/anti-inflammatory capability. Here, we investigated the therapeutic efficacy of using an infusion of MSCs to treat sex hormone-deficient bone loss and its underlying mechanisms. In particular, we compared the impacts of MSC cytotherapy in the two genders with the aim of examining potential gender differences. Using the gonadectomy (GNX) model, we confirmed that the osteoporotic phenotypes were substantially consistent between female and male mice. Importantly, systemic MSC transplantation (MSCT) not only rescued trabecular bone loss in GNX mice but also restored cortical bone mass and bone quality. Unexpectedly, no differences were detected between the genders. Furthermore, MSCT demonstrated an equal efficiency in rectifying the bone remodeling balance in both genders of GNX animals, as proven by the comparable recovery of bone formation and parallel normalization of bone resorption. Mechanistically, using green fluorescent protein (GFP)-based cell-tracing, we demonstrated rapid engraftment but poor inhabitation of donor MSCs in the GNX recipient bone marrow of each gender. Alternatively, MSCT uniformly reduced the $CD3^+T$-cell population and suppressed the serum levels of inflammatory cytokines in reversing female and male GNX osteoporosis, which was attributed to the ability of the MSC to induce T-cell apoptosis. Immunosuppression in the microenvironment eventually led to functional recovery of endogenous MSCs, which resulted in restored osteogenesis and normalized behavior to modulate osteoclastogenesis. Collectively, these data revealed recipient sexually monomorphic responses to MSC therapy in gonadal steroid deficiency-induced osteoporosis via immunosuppression/anti-inflammation and resident stem cell recovery.

New Methods for Correcting the Atmospheric Effects in Landsat Imagery over Turbid (Case-2) Waters

  • Ahn Yu-Hwan;Shanmugam P.
    • Korean Journal of Remote Sensing
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    • v.20 no.5
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    • pp.289-305
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    • 2004
  • Atmospheric correction of Landsat Visible and Near Infrared imagery (VIS/NIR) over aquatic environment is more demanding than over land because the signal from the water column is small and it carries immense information about biogeochemical variables in the ocean. This paper introduces two methods, a modified dark-pixel substraction technique (path--extraction) and our spectral shape matching method (SSMM), for the correction of the atmospheric effects in the Landsat VIS/NIR imagery in relation to the retrieval of meaningful information about the ocean color, especially from Case-2 waters (Morel and Prieur, 1977) around Korean peninsula. The results of these methods are compared with the classical atmospheric correction approaches based on the 6S radiative transfer model and standard SeaWiFS atmospheric algorithm. The atmospheric correction scheme using 6S radiative transfer code assumes a standard atmosphere with constant aerosol loading and a uniform, Lambertian surface, while the path-extraction assumes that the total radiance (L/sub TOA/) of a pixel of the black ocean (referred by Antoine and Morel, 1999) in a given image is considered as the path signal, which remains constant over, at least, the sub scene of Landsat VIS/NIR imagery. The assumption of SSMM is nearly similar, but it extracts the path signal from the L/sub TOA/ by matching-up the in-situ data of water-leaving radiance, for typical clear and turbid waters, and extrapolate it to be the spatially homogeneous contribution of the scattered signal after complex interaction of light with atmospheric aerosols and Raleigh particles, and direct reflection of light on the sea surface. The overall shape and magnitude of radiance or reflectance spectra of the atmospherically corrected Landsat VIS/NIR imagery by SSMM appears to have good agreement with the in-situ spectra collected for clear and turbid waters, while path-extraction over turbid waters though often reproduces in-situ spectra, but yields significant errors for clear waters due to the invalid assumption of zero water-leaving radiance for the black ocean pixels. Because of the standard atmosphere with constant aerosols and models adopted in 6S radiative transfer code, a large error is possible between the retrieved and in-situ spectra. The efficiency of spectral shape matching has also been explored, using SeaWiFS imagery for turbid waters and compared with that of the standard SeaWiFS atmospheric correction algorithm, which falls in highly turbid waters, due to the assumption that values of water-leaving radiance in the two NIR bands are negligible to enable retrieval of aerosol reflectance in the correction of ocean color imagery. Validation suggests that accurate the retrieval of water-leaving radiance is not feasible with the invalid assumption of the classical algorithms, but is feasible with SSMM.

Empirical Analysis of Selection Criteria of Container Ports in the Bay of Bengal (벵갈만 지역의 컨테이너항만 선택 기준에 관한 연구)

  • Lwin, Theingi;Kim, Hyundeok
    • Journal of Korea Port Economic Association
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    • v.34 no.4
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    • pp.69-84
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    • 2018
  • The purpose of this study is to provide a comparative evaluation of container port criteria at four major container ports in the Bay of Bengal, including Colombo Port in Sri Lanka, Chennai Port in India, Chittagong Port in Bangladesh and Yangon Port in Myanmar. Important container port selection criteria are identified and comparisons among container ports are made using previous studies, personal interviews and questionnaires, completed by top shipping companies, freight forwarders, logistics service providers, and experts in Myanmar. The AHP method is used to verify the research model and hypothesis. This study identified five main criteria and eleven sub-criteria when choosing potential regional hub ports among the four ports in the Bay of Bengal. The main findings from the five main criteria suggest that port efficiency is the highest priority criteria, and the second priority is port costs. The criteria of geographical location and available port facilities are the third and fourth most important, respectively, and the last priority is port's hinterland. Regarding the relative competition among these ports, Colombo Port obtained the highest priority among the four influential factors except for port hinterland. This study has certain limitations that will require future research. First, the sample group for the population size is relatively small. Second, interviewees had limited experience answering questionnaires using this methodology and a limited amount of time was available for respondents for the interviews.

Multiple Linear Regression Analysis of PV Power Forecasting for Evaluation and Selection of Suitable PV Sites (태양광 발전소 건설부지 평가 및 선정을 위한 선형회귀분석 기반 태양광 발전량 추정 모델)

  • Heo, Jae;Park, Bumsoo;Kim, Byungil;Han, SangUk
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.6
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    • pp.126-131
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    • 2019
  • The estimation of available solar energy at particular locations is critical to find and assess suitable locations of PV sites. The amount of PV power generation is however affected by various geographical factors (e.g., weather), which may make it difficult to identify the complex relationship between affecting factors and power outputs and to apply findings from one study to another in different locations. This study thus undertakes a regression analysis using data collected from 172 PV plants spatially distributed in Korea to identify critical weather conditions and estimate the potential power generation of PV systems. Such data also include solar radiation, precipitation, fine dust, humidity, temperature, cloud amount, sunshine duration, and wind speed. The estimated PV power generation is then compared to the actual PV power generation to evaluate prediction performance. As a result, the proposed model achieves a MAPE of 11.696(%) and an R-squred of 0.979. It is also found that the variables, excluding humidity, are all statistically significant in predicting the efficiency of PV power generation. According, this study may facilitate the understanding of what weather conditions can be considered and the estimation of PV power generation for evaluating and determining suitable locations of PV facilities.

A Study on the Flow Analysis for KP505 Propeller Open Water Test (유체기기의 표면 금속코팅 적용에 따른 구조건전성 평가)

  • Lee, Han-Seop;Lim, Byung-Chul;Kim, Min-Tae;Lee, Beom-Soon;Park, Sang-Heup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.8
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    • pp.23-28
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    • 2019
  • The structural integrity of a surface metal coating was evaluated through numerical results to improve the efficiency and reduce the damage caused by cavitation in ships and marine plants. The goal was to ensure structural strength and performance, even if the thickness of the wing is reduced to reduce the weight of the material and surface coating. Analytical methods were used for four models: a non-coating model, one with the same thickness after coating, one with a thickness reduction of 3% after coating, and one with thickness reduction of 5% after coating. With a thickness reduction of 5% after coating, the stress was increased to 12%, and the safety factor was 0.99%, so the structural integrity was insufficient. However, a better material or a thicker coating could allow a sufficient safety factor to be secured. The structural integrity was improved by the coating, and even when the weight was reduced up to 5%, the structural integrity could be sufficiently secured due to the coating effect.

An Economic Ripple Effect Analysis of National Science & Technology Information Service : Focusing An Input-Output Analysis (국가과학기술지식정보서비스의 경제적 파급효과에 관한 연구 : 산업연관분석을 중심으로)

  • Park, Sung-Uk
    • Journal of Korea Technology Innovation Society
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    • v.21 no.4
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    • pp.1296-1312
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    • 2018
  • The wave of the Fourth Industrial Revolution was spreaded in Moon Jae-in Government. The efficiency of the R&D budget of government began to pay attention, the role of the National Science & Technology Information Service (NTIS) which provides all national R&D information in real time World's first R&D information portal has been emphasized. NTIS provides information on national R&D projects with their participating researchers, outcomes, and facilities & equipment through of information from each ministry and institution. NTIS supports to build science and technology policies, to enable transparent and efficient management of national R&D projects and to promote joint utilization of the R&D data among researchers and industrial utilization of the R&D data. NTIS provides since 2005. In this paper, I have analyzed the economic ripple effect of NTIS using the Input-Output model technique based on the input-output tables published by the Bank of Korea. When I set the NTIS R&D budget (about 120M$ for the last 13 years) as input coefficients, the effect on production inducement, value added inducement and employment inducement was analyzed by 211M$, 100M$ and 1,882 respectively.

Study on the Risk Management of the CERs Investment - Regarding Registration Risks and Price Change Risk in Investing Primary CERs - (탄소배출권 투자와 위험관리방안 연구 - 일차배출권(Primary CER) 투자 시 등록위험 및 가격변동 위험을 중심으로 -)

  • Lee, Chang Seok;Kim, Yun Soung;Jeon, Eui Chan
    • Journal of Climate Change Research
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    • v.2 no.2
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    • pp.115-131
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    • 2011
  • Out of all the possible actions that can be taken to respond to greenhouse gas reduction, including development of greenhouse gas reduction technology, infrastructure, actions to improve energy saving and efficiency, and offset with carbon emission reductions (CERs), this study shall focus on the investment on CERs. This study will take a look at risks involved with investing in CERs such as UN registration refusal risk and CERs price fluctuation, and will design risk management model which shall be verified. The goal of this paper is to provide optimized CERs investment strategies for different types of investors, such as general trading companies seeking for investment opportunities and financial companies with plans for green products development and investment by preparation for carbon market. It is expected that the global competitiveness of domestic financial companies shall be improved by taking actions on carbon market instead of previous passive response to climate change and that Korea, the number two Carbon Emissions supplier and number one derivatives market in terms of volume, shall be able to lead the worldwide carbon market.

Evaluation of Operational Options of Wastewater Treatment Using EQPS Models (EQPS 모델을 이용한 하수처리장 운전 평가)

  • Yoo, Hosik;Ahn, Seyoung
    • Journal of the Korean Society of Urban Environment
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    • v.18 no.4
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    • pp.401-408
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    • 2018
  • EQPS (Effluent Quality Prediction System, Dynamita, France) was applied to analyze the appropriateness of the design of a bioreactor in A sewage treatment plant. A sewage treatment plant was designed by setting the design concentration of the secondary clarifier effluent to total nitrogen and total phosphorus, 10 mg/L and 1.8 mg/L, respectively, in order to comply with the target water quality at the level of the hydrophilic water. The retention time of the 4-stage BNR reactor was 9.6 hours, which was 0.5 for the pre-anoxic tank, 1.0 for the anaerobic tank, 2.9 for the anoxic tank, and 5.2 hours for the aerobic tank. As a result of the modeling of the winter season, the retention time of the anaerobic tank was increased by 0.2 hours in order to satisfy the target water quality of the hydrophilic water level. The default coefficients of the one step nitrification denitrification model proposed by the software manufacturer were used to exclude distortion of the modeling results. Since the process modeling generally presents optimal conditions, the retention time of the 4-stage BNR should be increased to 9.8 hours considering the bioreactor margin. The accurate use of process modeling in the design stage of the sewage treatment plant is a way to ensure the stability of the treatment performance and efficiency after construction of the sewage treatment plant.