• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.23-30
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• 2012

For cracked concrete, it is obvious that cracks should be preferential channel for the penetration of aggressive substances such as chloride ions according to the previous researches. In order to extend the lifetime of cracked concrete, critical issues in the performance of the concrete is the risk of chloride-induced corrosion. Even though crack width can be reduced due to the high reinforcement ratio, the question is to which extend these cracks may jeopardize the durability of cracked concrete. If the size of crack is small, surface treatment system can be considered as one of the best options to extend the service life of concrete structures exposed to marine environment simply in terms of cost effectiveness versus durability performance. Thus, it should be decided to undertake an experimental study on the effect of surface coating system, which can be able to seal the concrete and the cracks to aggressive substances-induced corrosion in particular. In this study, it is excuted to examine the effect of surfaced treated systems on chloride penetration and carbonation through compressive stress induced cracks. Experimental results have showed conclusively that critical stress linked with deterioration, should be existed in compressive stress ratio 50 ~ 70% for chloride penetration and 70 ~ 80% for carbonation, respectively. When the critical stress is exceeded in concrete, a comparatively large deterioration was measured where the critical stress in concrete, the increase in the mass transportation is marginal in spite of the large increase in micro-cracks. As for the effect of surface coating system on crack-sealing, it can be seen conclusively that cracks can be healed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.729-738
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• 2017

With the signing of the Paris Agreement, which is the new climate change agreement at the end of 2015, it will have a great impact on Korea environmental policy. The construction industry, which accounts for 42% of Korea's total $CO_2$ emissions, has been implementing various policies to improve the environmental problems. However, it is only applying passively to other projects except eco-friendly building certification. This is because most of the eco-related systems are based on building facilities. Therefore, there is a need for a new eco - friendly design evaluation model that can be widely applied not only to architecture but also to civil engineering facilities. In this study, a new model is developed based on the existing VE model, which adds new factors to evaluate the environmental friendliness, potential environmental pollution concept and environmental risk of facilities. This model is an eco-friendly design evaluation model that enables decision makers to effectively select alternative environmental criteria at the design stage. As a result of the case analysis of the block retaining wall and the alternative retaining wall, the value of the eco - friendly value of the alternative was 1.026 times higher than the original one. If this model is used at the design stage, it is expected to contribute not only to the construction of environmentally friendly facilities but also to the reduction of carbon emissions.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.111-121
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• 2020

Realistic training contents utilizing intensive immersion of virtual reality are being used in various fields such as industry, education, and medical care. High-risk, high-cost education training, in particular, is difficult to conduct in reality, but it can be applied with the latest virtual reality technology that enhances educational effectiveness by efficiently and safely experiencing it in an environment similar to reality. This study introduces a management system that systematically manages realistic virtual training contents and visualizes training results in schematic pictures based on defined evaluation elements. The management system can store the information generated from the content in the database and manage the training records of each trainee in a practical way. In addition, a content-based scenario can be created in multiple scenarios by setting training goals, number of participants, and methods for applying evaluation elements. This paper describes the management system's production method and the results based on the virtual reality training content as an application example.

• Korean Journal of Construction Engineering and Management
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• v.11 no.1
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• pp.59-69
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• 2010

Although international construction market gradually takes a important position among the export industries, the previous studies about international construction entry strategy have just focussed on trend investigation or suggestion for revitalization. Moreover, in order to prepare the market uncertainty such as world financial crisis and to plan the long term strategy, specific strategy studies based on corporate level are required. Therefore, this study estimates the nine strategic index and four financial index of 31 companies that performed 1920 international projects from 1993 to 2007 and evaluate the performance as three periods by multi-regression analysis. Also, this study analyze dynamic correlation between these index and the performance considering times. this study verifies that market diversification, product diversification, localization and decrease of debt to asset ratio make a good effect on the international order as long term strategy and shows that collaborated entry with domestic corporations, alliance entry with host country's company, alliance entry with third country's company, portion of labor cost and portion of management expense differently make a influence on the performance as times. these results will be helpful for the construction companies to plan the international entry strategy reasonably and specifically.

• Management & Information Systems Review
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• v.35 no.2
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• pp.45-66
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• 2016

Firms can make scale of economy and scope of economy by internalizing and using new advanced technology and knowledge from technology cooperation network, decrease risk and cost with partner firm of technology cooperation network, and increase market advantage of product & strengthen firms' position in the market. Due to the advantages of technology cooperation network, the related studies have focused on the positive effect of technology cooperation network. However, the related studies investigating the relationship between technology cooperation network and firm performance have only examined the role of technology cooperation network. Safeguarding mechanism, relationship learning, and relationship performance are categorized into the process of technology cooperation network, and this categorization is applied as resources, capability, and performance by resource based view. The empirical results are reported as belows. First, relationship specific investment and relationship capital positively affect on relationship learning as capability. Second, information sharing, common information understanding, and relationship specific memory development positively affect on long-term orientation, but information sharing has no impact on efficiency and effectiveness. Third, relationship specific investment positively affects on relationship capital and efficiency and effectiveness have positive effects on long-term orientation. Applying technology cooperation network in asymmetric technology dependency with resource based theory, this study suggested the importance of both safeguarding and relationship learning by investigating the relationship among safeguarding, relationship learning, and relationship performance. And it is worthy that this study investigated how firms' behavior change affects relationship performance in the relationship of technology cooperation partner.

• Progress in Medical Physics
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• v.13 no.1
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• pp.32-36
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• 2002

For Intensity Modulated Radiation Therapy(IMRT), the spatial resolution of intensity map(IM) is limited by the width of multi-leaf collimator, which would make an effect on the conformity of the target, as well as organs at risk. Several Methods are suggested to increase the spatial resolution, which can be categorized by the hardware-dependent technique and the software-based technique. However the best solution might be to make the width of MLC finer. it has several obstacles in the respects of technical difficulty and cost. This preliminary study is designed to investigate the clinical effectiveness of the virtual-micro IMRT(VMIMRT) technique, one of the software-based technique. A particular intensity map was created, which has 42$\times$54 pixel dimension ,0.5cm pixel size and 15 intensity levels. Using this intensity map, segment fields of IMRT were generated with 1$\times$lcm, 0.5$\times$1cm, 0.5$\times$0.5cm(VMIM) beamlet size, respectively As results, we found that there was no evidence of improvement for VMIMRT, compared with the 0.5$\times$lcm beamlet size which can be delivered by 1cm width MLC. The reason seems to be due to the constraint of VMIMRT. Further study is required to prove the benefit of the VIMRT in clinical case like head and neck cancer, where is expected that higher resolution than 1cm is necessary.

• Journal of Korea Port Economic Association
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• v.27 no.2
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• pp.297-311
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• 2011

This paper deals with a strategic investment decision model for improving investment profit in shipping industry. Despite the quantitative expansion of Korean shipping business, many shipping firms have suffered financial difficulties due to financial and operating risks that result from the characteristics of capital-intensive business as well as of volatility of shipping markets. As a result, managers in charge of making an investment decision, particularly in tramper business sector, are required to take both financial and operating risk factors into consideration. Put it differently, managers are strongly recommended to avoid these risks by ship asset play; buy-low and sell-high, which results in considerable capital gain and cost reduction. In addition, managers in shipping industry are also recommended to consider the ship chartering investment alternative when the freight markets show extreme volatility as the case of 2008 triggered by sub-prime mortgage financial crisis in USA. For example, the BDI suffered plunging down from 1000 in 2008 to 100 in 2010. Consequently, the 4th largest shipping company in Korea, DAEHAN Shipping Co., has collapsed primarily due to excessive tonnage expansion during the peak time of bulk market. In sum, the strategic investment decision model, suggested in this paper, is designed to include such factors as capital gain by asset play, timely chartering for alternative shipping service, and optimization of operating profit by tonnage adjustment in accordance with change in the shipping markets concerned.

• Journal of Korean Academy of Nursing
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• v.25 no.3
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• pp.472-484
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• 1995

The purpose of this study was to develop a home health care model in the public health system and to test the effectiveness of the model. Seven com-munity health practitioners in Yon- Cheon county. Kyunggi province, carried out home health care service for this research. The subjects of the home health care were a total of 111 community residents with chronic health problems and risk-prone infants and children; 29 persons with hypertension, 18 persons with diabetes, 12 persons with neurologic problems, 12 elderly, and 40 infants and children. During the period of study, from December, 1993 to March, 1995, a demonstrative home health care model was developed in the Yon-Cheon County community health centers with the cooperation of the Yon-Cheon Medical Center and Yon-Cheon Public Health Center for the first six months. A home care practice manual and recording system for home visits were also co-developed by the researchers and community health practitioners. Four workshops and monthly conferences were held for this purpose. Actual home care practice took place for two months, and on-going evaluation and replanning accompanied this process. The result of the evaluation of home care service were as follows. 1) For persons with hypertension, diabetes, neurologic problems, there was significant improvement in knowledge of disease and care, but no significant difference was seen in health behavior or symptoms after home care service. 2) No significant difference was seen in level of self esteem or depression after reminiscence therapy among 12 elderly subjects. 3) There were significant differences in satis-faction toward child rearing and parental sup-port, but no significant difference In education needs for parental role after home care service among parents of infants and children. 4) There was significant improvement in the quality of life among the subjects after the home care service. 5) Subjects responded that they were highly satisfied with the home care service given by the community health practitioners. Although, the actual implementation period was very short, and not all of the evaluation outcomes showed significant improvement, the home health care model of community health practitioners was, in general, positively evaluated. Through this re-search, the possibility of community health practitioners working as active home care personnel in the public health care system is supported. Further research with an expanded area and subjects for a longer period is recommended. Cost effectiveness research is also needed.

• Journal of the Korea Society for Simulation
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• v.26 no.2
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• pp.41-49
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• 2017

In the acquisition program, the conceptual design is the most important step toward specifying the military objectives, establishing requirements and determining future developmental directions, of a target system. However, if both the requirements and directions are incorrectly set due to the lack of development experiences and literature backgrounds in the target systems, such as future ground combat vehicles, it may become a major risk in the future design phases and the entire acquisition program. In order to correct these errors in the future phases, time, effort and cost are required. Therefore, it is necessary to reduce the errors that occur in the initial stages to effectively acquire the future ground combat vehicles. This paper describes the initial design method for verifying the requirements and the developmental directions and estimating the system performance at the conceptual design through the system-level physical modeling and simulation (M&S) and the target system performance analysis. The system-level physical M&S use cutting-edge design tools, model-based designs and geometric-based designs. The system performance estimation is driven from the results of the system-level physical M&S and the specialized system analysis software.

• Tuberculosis and Respiratory Diseases
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• v.69 no.6
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• pp.434-441
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• 2010

Background: Chronic obstructive pulmonary disease (COPD) is a major health problem resulting in significant burden for patients and families. However, family caregivers' burden has not been well recognized. The objectives of this study were to evaluate the level of caregivers' burden and to explore the related factors based on family, patient, and social support factors. Methods: A face-to-face interview with 86 family caregivers who had been taking care of COPD patients was conducted. The participants answered a self-administered questionnaire. The questionnaire included the level of family caregivers' burden, health status and the relationship within the family, functional limitation of patients perceived by family caregivers and the social support. Results: The level of caregivers' burden among participants was considerably high. Risk factors for caregivers' burden included low educational level of family caregivers, low family income, hours of caregiving, and functional limitation of the patients. Protective factors for caregivers' burden were good relationship within the family and support from other family members or friends. Conclusion: It is proved that family caregivers are facing significant burden in taking care of COPD patients. To reduce family caregivers' burden, it is necessary to address socioeconomic status of the family and to provide various community resources including financial support and nursing services.