• Journal of Power Electronics
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• v.15 no.5
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• pp.1318-1328
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• 2015

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.

• Asia pacific journal of information systems
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• v.25 no.4
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• pp.763-783
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• 2015

Online customer reviews (i.e., electronic word-of-mouth) has gained considerable interest over the past years. However, a knowledge gap exists in explaining the mechanisms among the factors that determine the product sales in online retailing environment. To fill the gap, this study adopts a principal-agent perspective to investigate the effect of customer reviews and customer incentives on product sales in online retail stores. Two customer review factors (i.e., average review ratings and the number of reviews) and two customer incentive factors (i.e., price discounts and special shipping offers) are used to predict product sales in regression analysis. The sales ranking data collected from the video game titles at Amazon.com are used to analyze the direct effects of the four factors and the interaction effects between customer review and customer incentive factors to product sales. Result reveals that most relationships exist as hypothesized. The findings support both the direct and interaction effects of customer reviews and incentive factors on product sales. Based on the findings, discussions are provided with regard to the academic and practical contributions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.914-934
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• 2016

In the mobile distributed environment, an entity may move across domains with great frequency. How to utilize the trust information in the previous domains and quickly establish trust relationships with others in the current domain remains a challenging issue. The classic trust models do not support cross-domain and the existing cross-domain trust models are not in a fully distributed way. This paper improves the outstanding Certified Reputation (CR) model and proposes a Lightweight Cross-domain Trust (LCT) model for the mobile distributed environment in a fully distributed way. The trust certifications, in which the trust ratings contain various trust aspects with different interest preference weights, are collected and provided by the trustees. Furthermore, three factors are comprehensively considered to ease the issue of collusion attacks and make the trust certifications more accurate. Finally, a cross-domain scenario is deployed and implemented, and the comprehensive experiments and analysis are conducted. The results demonstrate that our LCT model obviously outperforms the Bayesian Network (BN) model and the CR model in our cross-domain scenario, and significantly improves the successful interaction rates of the honest entities without increasing the risks of interacting with the malicious entities.

• The Journal of the Korea Contents Association
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• v.12 no.6
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• pp.160-169
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• 2012

'YTN Science TV' that is the only one specializing in science channel in domestic have struggled low ratings and the restricted access in spite of the performance and significance that it has contributed to the population of science. This study will seek alternatives and development challenges through the comparison with the similar channel of international for the activation of the science channel. Accordingly, this study is to review the BBC knowledge channel that have contributed the successful overseas expansion and the education for the people of its country in pursuing commercial and public interest. This study will provide significant in the activation of the science channel in domestic through review of such cases.

• Journal of the Korean Society of Physical Medicine
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• v.7 no.3
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• pp.283-291
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• 2012

Purpose : The purpose of this study was to identify education, attitudes and beliefs, interest and perceived role, self-efficacy and barriers to physical therapists' implementation of evidence-based practice for people with stroke. Methods : The participants were 120 physical therapists providing services to people with stroke in Gwang-ju. The questionnaire contained items to evaluate practitioner and organizational characteristics and perceptions of research considered to influence evidence-based practice. The prevalence of practitioner and organizational factors was estimated using percentages. Logistic regression was used to examine relationships between sociodemographic and practice characteristics and each practitioner factor. Results : 40% of respondents had learned the foundations of EBP in their academic preparation or received training in searching or appraising research literature. 88.3% agreed that research findings are useful. Self-efficacy ratings were 45%. Conclusion : Lack of education, negative perceptions about research and physical therapists' role in evidencebased practice, and low self-efficacy to perform EBP activities represent barriers to implementating EBP for people with stroke that can be addressed through continuing education.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.119-124
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• 1999

A selection methodology of liquid levelmeters, especially, level sensors in non-nuclear category, to be installed in nuclear energy facilities is developed using linguistic fuzzy approaches such as fully-linguistic and semi-linguistic methods. Depending on defuzzification techniques, the linguistic fuzzy methodology leads to either linguistic (exactly, fully-linguistic) or cardinal (i.e., semi-linguistic) evaluation. For the linguistic method, for each alternative, fuzzy preference index is converted to linguistic utility value by means of a similarity measure determining the degree of similarity between fuzzy index and linguistic ratings. For the cardinal method, the index is translated to cardinal overall utility value. According to these values, alternatives of interest are linguistically or numerically evaluated and a suitable alternative can be selected. Under given selection criteria, the suitable selections out of some liquid levelmeters for nuclear facilities are dealt with using the linguistic fuzzy methodology proposed. Then, linguistic fuzzy evaluation results are compared with qualitative result available in the literature. It is found that as to a suitable option the linguistic fuzzy selection is in agreement with the qualitative selection. Additionally, the comparative study shows that the fully-linguistic method using adequate scale system facilitates linguistic interpretation regarding evaluation results.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.207-218
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• 2020

Recently, due to the increase of online reviews and the development of analysis technology, the interest and demand for online review analysis continues to increase. However, previous studies have not considered the emotions contained in each vocabulary may differ from one reviewer to another. Therefore, this study first classifies the customer group according to the customer's grade, and presents the result of analyzing the difference by performing review analysis for each customer group. We found that the price factor had a significant influence on the evaluation of products for customers with high ratings. On the contrary, in the case of low-grade customers, the degree of correspondence between the contents introduced in the mall and the actual product significantly influenced the evaluation of the product. We expect that the proposed methodology can be effectively used to establish differentiated marketing strategies by identifying factors that affect product evaluation by customer group.

• Fire Science and Engineering
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• v.25 no.4
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• pp.1-7
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• 2011

Recently the interest in disaster prevention on super tall buildings is increasing. Especially in fire, against increasing of evacuation time due to high-rise, It is being tried to minimize the fire spread in building. Fire compartments using the fire-resistant wall and door, typical method to control the fire spread in buildings, delay the fire spread to other compartments and consequently evacuation time increases. But the existing provisions adjure only 2-hour fire resistance with maximum limit regardless of the super tall buildings, so this is a obstacle for research and development of the fire resistance wall in super tall buildings. In this study, we reviewed the fire resistance ratings of the wall, and presented the development directions for the fire resistance wall in super tall buildings considering fire resistance, construction and application of the wall.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.684-695
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• 2001

Recent recommender system uses a method of combining collaborative filtering system and content based filtering system in order to solve sparsity and first rater problem in collaborative filtering system. Collaborative filtering systems use a database about user preferences to predict additional topics. Content based filtering systems provide recommendations by matching user interests with topic attributes. In this paper, we describe a method for discovery of user preference through combining two techniques for recommendation that allows the application of machine learning algorithm. The proposed collaborative filtering method clusters user using genetic algorithm based on items categorized by Naive Bayes classifier and the content based filtering method builds user profile through extracting user interest using relevance feedback. We evaluate our method on a large database of user ratings for web document and it significantly outperforms previously proposed methods.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.61
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• pp.273-302
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• 2014

Project finance ("PF") is a method of raising long-term debt financing based on lending against the cash flow generated by the project alone. Project finance is a nonrecourse or limited recourse financing structure against the sponsors(or the investors). The debt terms in a project finance are not based on the creditor's credit support or on the value of the assets of the project. Lenders rely on the future cash flow to be generated by the project for debt repayment and interest, rather than the value of the project or the credit ratings of the sponsors. The non-recourse or limited recourse financing usually prompt potential project finance lenders to assess carefully all possible risks that might arise in a project to ensure that those risks are mitigated and controlled. In this respect, project finance is a opposite financing method of corporate finance. Project finance has rapidly grown over the last 20 years due to the worldwide process of privatization of public sector and development of natural resources. Global project finance volume reached the record USD 406.5 billion in 2011. In 2012, however, Global project finance volume dropped 6% to USD 382.3 billion. Infrastructure overtook Energy to lead all sectors with USD 113.6 billion. It is generally recognized that there are more and higher risks in project finance compared with corporate finance. Project finance is exposed to commercial risks as well as political risks. The main commercial risks are completion risks, environmental risks, operating risks, input supply risks, revenue risks, etc, and the main political risks are currency convertibility and transfer risks, expropriation risks, war and civil disturbance risks, risks of breach of government concession agreement, etc. Completion risks include permits risks, risks relating to the EPC Contractor, construction cost overrun, delay in completion, inadequate performance on completion, etc.