• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.122-128
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• 2016

In the future, hybrid power management systems using fuel cells (FCs) and batteries will be used as the driving power systems of ships. These systems consist of an FC, a converter, an inverter, and a battery. In general, an FC provides steady-state energy; a battery provides the dynamic energy in the start state of a ship for enabling a smooth operation, and provides or absorbs the peak or dynamic power when the load varies and the FC cannot respond immediately. The FC voltage range is very wide and depends on the load; Therefore, the FC cannot directly connect to the inverter. In this paper, we propose a power management strategy and design process involving a unidirectional converter, a bidirectional converter, and an inverter, considering the ship's operating conditions and the power conditions of the FC and the battery. The presented experimental results were verified through a simulation.

• The Korean Journal of Ecology
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• v.21 no.6
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• pp.779-789
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• 1998

The forest vegetation established on Mt. Hwangryung located in Pusan, southern Korea was analyzed through phytosociological procedure. Vegetation of the study area was categorized into 14 communities, 16 groups, and 13 subgroups. Vegetation units obtained from such an analysis were shown in a detailed vegetation map (scale 1:5,000). Ecological characteristics of each vegetation unit were discussed on the basis of the principle of restoration ecology. From those results, it was confirmed that some introduced vegetation under excessive artificial interference was in unstable state and then ecological restoration was needed. On the other hand, ecological information and management systems to maintain the urban forest as ecologically healthy state were developed using GIS.

• Journal of Korean Physical Therapy Science
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• v.7 no.1
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• pp.333-352
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• 2000

The objective of this study was to identify the effects of the cognitive performance of stroke patients on their motor function recovery after comprehensive rehabilitation management. The subjects of this study were 41 stroke in-patients of the Rehabilitation Hospital, College of Medicine, Yonsei University, hospitalized during the period from September 1, 1997 to May 5, 1998. The cognitive performance was measured using a Mini-Mental State Examination(MMSE) and the motor function recovery using Motor Assessment Scale(MAS). The data were analyzed by the paired t-test, independent t-test, a one way ANOVA, and Pearson's correlation coefficiency. The findings were as follows: 1. There was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 2. There was no significant difference found in relation to sex, age, cause of stroke, laterality of paralysis and the level of spasticity. However, there was a big difference between pre- and post-treatment regarding the treatment period. 3. In line with the cognitive performance level, there was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 4. The correlation between the elements of the cognitive performance and the motor recovery was found to be high in orientation, attention, calculation, and language. Those elements were expected to give larger effects on motor recovery after the comprehensive rehabilitation management. Based on this study, the cognitive performance level was found to play an important role in bringing effects on motor recovery after the comprehensive rehabilitation management of stroke patients. And the evaluation on the motor recovery based on quality would be also expected to be examined, as well as the cognitive performance level test accompanied by Intelligence Quality(IQ) test.

• Journal of Smart Tourism
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• v.1 no.3
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• pp.21-29
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• 2021

This study explored the relationship between post types and linguistic characteristics in marketer-generated content and social media engagement to find the optimized content to enhance social media engagement level. Post data of 23,588 marketer-generated content were collected from 50 states' destination marketing organization Facebook pages in the United States. The collected data were analyzed by employing social media analytics, linguistic analysis, multivariate analysis of variance, and discriminant analysis. The results showed that there are significant differences in both engagement indicators and linguistic scores among the three post types. Based on research findings, this research not only provided researchers with theoretical implications but also suggested practitioners the most effective content designs for travel destination marketing in Facebook.

• Journal of Ginseng Research
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• v.40 no.1
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• pp.28-37
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• 2016

Background: Panax ginseng cannot be cultivated on the same land consecutively for an extended period, and the underlying mechanism regarding microorganisms is still being explored. Methods: Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) and BIO-LOG methods were used to evaluate the microbial genetic and functional diversity associated with the P. ginseng rhizosphere soil in various cultivation ages and modes. Results: The analysis of microbial diversity using PCR-DGGE showed that microbial communities were significantly variable in composition, of which six bacterial phyla and seven fungal classes were detected in P. ginseng soil. Among them, Proteobacteria and Hypocreales dominated. Fusarium oxysporum, a soilborne pathogen, was found in all P. ginseng soil samples except R0. The results from functional diversity suggested that the microbial metabolic diversity of fallow soil abandoned in 2003was the maximum and transplanted soil was higher than direct-seeding soil and the forest soil uncultivated P. ginseng, whereas the increase in cultivation ages in the same mode led to decreases in microbial diversity in P. ginseng soil. Carbohydrates, amino acids, and polymers were the main carbon sources utilized. Furthermore, the microbial diversity index and multivariate comparisons indicated that the augmentation of P. ginseng cultivation ages resulted in decreased bacterial diversity and increased fungal diversity, whereas microbial diversity was improved strikingly in transplanted soil and fallow soil abandoned for at least one decade. Conclusion: The key factors for discontinuous P. ginseng cultivation were the lack of balance in rhizosphere microbial communities and the outbreak of soilborne diseases caused by the accumulation of its root exudates.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.05a
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• pp.65-69
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• 2004

The need for developing sustainable solutions for managing the animal waste is vital for the future of the animal industry in North Carolina. As part of that process, the North Carolina Attorney General has concluded that the public interest will be served by the development and implementation of environmentally superior swine waste management technologies appropriate to each category of hog farms. To facilitate in the development, testing, and evaluation of potential technologies it is necessary that all aspects of environmental issues (air, water, soil, odor and odorants, and disease-transmitting vectors and airborne pathogens) be addressed as Part of a comprehensive strategy, Program OPEN (Odor, Pathogens, and Emissions of Nitrogen) Is comprehensively addressing these issues.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.11
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• pp.1157-1163
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• 2009

This paper introduces the lithium ion battery management system for STSAT-3 satellite. The specifications of lithium ion battery unit are proposed to supply power to the satellite and the overall electrical design for lithium ion battery BMS is presented. Furthermore, the test results of battery management system are shown to verify the design.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.6 s.154
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• pp.829-839
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• 2006

Sustainable development is generally defined as an approach that 'meets the needs of the present without compromising the ability of future generations to meet their own needs' (World Commission on Environment and Development: WCED, 1987, p. 43). The sustainable development is a holistic concept that encompasses three aspects: environmental protection, economic development, and social contribution. From the sustainable development perspective, environmental management must consider contributions to other economic and social aspects. In this sense, it differs from narrowed environmental management which focuses on only environmental impacts, and a well-being concept in Korea that mainly appeals to health. Recently, leading apparel firms, such as Nike, Otto, and Marks & Spencer, are increasingly adopting the environmental management to achieve the future competitive advantage. The environmental management can be achieved through integrated supply chain management. Despite of flowing importance of environmental supply chain management in practice, academic attention to this area has been seriously lacking. This study regards the environmental management by the sustainable development perspective as a solution for Korean apparel firms to solve their current sluggish growth. The purpose of this study was to provide Korean apparel firms with guidelines toward the environmental management based on extensive literature reviews and case studies. The paper started with two important research frameworks, the sustainable development and the environmental supply chain. Within the frameworks, the leading cases of the environmental management of Korean and foreign apparel firms were analyzed. Both macroscopic and microscopic applications of the environmental supply chain management for Korean apparel firms were suggested based on the analyses.

• Korean Management Science Review
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• v.33 no.4
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• pp.65-75
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• 2016

We study limit pricing in a price-based duopoly market under asymmetric information on the demand state. An incumbent, who is a monopolist in the initial period, has complete information on the size of a market, while a potential entrant only knows it partially. After observing the sales price of the incumbent in the first period, the entrant decides whether to enter a duopoly market and the sales price if she chooses to. We present a separating perfect Bayesian equilibrium, which indicates that limit pricing can deter the entry of a potential entrant under price competition when there is information asymmetry about the demand state.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.122-128
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• 2013

Computer simulations designed to predict technical and financial returns of wind turbine installations are used to make informed investment decisions. These simulations used fixed values to represent real-world variables, while the actual projects can be highly uncertain, resulting in predictions that are less accurate and less useful. In this article, by modifying a popular wind power simulation sourced from the American Wind Energy Association to use Monte Carlo techniques in its calculations, the authors have proposed a way to improve simulation usability by producing probability distributions of likely outcomes, which can be used to draw broader, more useful conclusions about the simulated project.