• Journal of Power Electronics
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• v.16 no.4
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• pp.1426-1437
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• 2016

In different industrial and mission oriented applications, redundant or standby semiconductor systems can be implemented to improve the reliability of power electronics equipment. The proper structure for implementation can be one of the redundant or standby structures for series or parallel switches. This selection is determined according to the type and failure rate of the fault. In this paper, the reliability and the mean time to failure (MTTF) for each of the series and parallel configurations in two redundant and standby structures of semiconductor switches have been studied based on different failure rates. The Markov model is used for reliability and MTTF equation acquisitions. According to the different values for the reliability of the series and parallel structures during SC and OC faults, a comprehensive comparison between each of the series and parallel structures for different failure rates will be made. According to the type of fault and the structure of the switches, the reliability of the switches in the redundant structure is higher than that in the other structures. Furthermore, the performance of the proposed series and parallel structures of switches during SC and OC faults, results in an improvement in the reliability of the boost dc/dc converter. These studies aid in choosing a configuration to improve the reliability of power electronics equipment depending on the specifications of the implemented devices.

• KIEAE Journal
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• v.17 no.1
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• pp.43-48
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• 2017

Purpose: Building owners or residents have concerns to strive for energy-saving and environmental conservation by utilizing with eco-friendlier energy resources for their physical environment. In this paper, an algae façade system is proposed as an energy-friendly building component to improve energy productivity and indoor environmental quality, and this study aims at verifying alternative technologies for implementing building elevations that contain various colors equipped with algae façade systems and suggesting design guidelines to enhance both building performance and design values. Method: The color of algae is basically ranged about the saturation green, and it is hardly converted to other variations. Such a problem can be resolved through the artificial lights like LED (Light Emitting Diode) lamps to mix the color from the algae and buildings could possibly change the elevation in many ways under the influence of daylight. Result: As a result, the suggested system may increase the aesthetic aspect of the building in response to environmental changes. The system cannot possibly be applied for only new construction, but also it can be utilized with the existing buildings as well. The proposed system is expected to be applied not only a new construction and any existing buildings as well, and it will cover from the environmentally friendly energy generation in the industry to a new application system for increasing energy efficiency and the beauty of building envelopes.

• Advances in Energy Research
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• v.3 no.3
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• pp.157-165
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• 2015

This research investigates the effect of natural dust accumulation on the glass cover of solar thermal energy conversion systems. Four similar, locally manufactured, flat plate solar collectors are used. All collectors are South oriented with tilt angle of $40^{\circ}$. The glass cover of one collector is kept clean of dust during the experimental period while the second collector is cleaned at the beginning of each month. The third collector is cleaned every two months while the fourth collector is kept un-cleaned throughout the experimental period of four months. The calculated parameters are the solar heat gain rates and the corresponding values of the thermal efficiency. The result of the present work indicates that the percentage of fractional reduction of the useful heat gain rate due to dust accumulation during a period of one and two months is 11.4% and 17.0%, respectively. The percentage decrease of thermal efficiency during the same duration periods is 4.0% and 6.1%, respectively. The percentage of fractional reduction of the useful heat gain rate due to dust accumulation during a period of three and four months is 27.8% and 31.9%, respectively. The percentage decrease of monthly thermal efficiency during the same duration period is 10.2% and 11.3%, respectively.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.236-247
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• 2016

Considering the prevalent use of mobile devices and the mobile Internet in Korea, there should be open doors for retailers to a different type of distribution if they could find out what makes consumers satisfied with m-commerce sites as well as what makes consumers purchase from m-commerce sites. Therefore, we explored: 1) the antecedents of satisfaction with m-commerce sites and 2) the determinants of purchasers vs. browsers of m-commerce. As possible antecedents of the two dependent variables, the following were utilized in the current study: the Technology Acceptance Model (TAM), perceived shopping values, and interactivity. According to the results of this study, these variables related to the performance of mobile commerce sites (Perceived ease of use, Perceived usefulness, Synchronicity, Richness of content, and Contextual services) significantly affected satisfaction with m-commerce sites. On the other hand, the most important discriminator of an m-commerce purchaser vs. a browser was human-oriented interactivity, especially interpersonal communication among users. With the help of information technology.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.6
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• pp.471-476
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• 2016

In this paper, recognition system for continuous human action is explained by using motion history image and histogram of oriented gradient with spotter model based on depth information, and the spotter model which performs action spotting is proposed to improve recognition performance in the recognition system. The steps of this system are composed of pre-processing, human action and spotter modeling and continuous human action recognition. In pre-processing process, Depth-MHI-HOG is used to extract space-time template-based features after image segmentation, and human action and spotter modeling generates sequence by using the extracted feature. Human action models which are appropriate for each of defined action and a proposed spotter model are created by using these generated sequences and the hidden markov model. Continuous human action recognition performs action spotting to segment meaningful action and meaningless action by the spotter model in continuous action sequence, and continuously recognizes human action comparing probability values of model for meaningful action sequence. Experimental results demonstrate that the proposed model efficiently improves recognition performance in continuous action recognition system.

• Culinary science and hospitality research
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• v.15 no.2
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• pp.205-218
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• 2009

The purpose of this study was to analyze what effects the service quality of the food and beverage section have on its organization value in the value-oriented hotel business, how the organization value influence work performance, and what causal relationships exist among variable factors such as service quality, organization value, and work performance for helping get the hotel business more profitable through guiding service improvements. For conducting the study, full-time staff working at the restaurants of premium hotels in Seoul participated in the test as samples from January 10th to January 22nd, 2009. The statistical data analyses were completed using the SPSS 12.0 program, and frequency analyses, reliability analysis, factor analysis, multiple regression analysis were conducted. The main results of this study were as follows. First, service quality of the food and beverage section in the hotel business caused positive effects on organization values. Second, it was found that the organization value and service quality also positively influenced work performance. Third, among service quality, organization value, and work performance, service quality had a direct effect on business performance, and organization value played an indirect role to cause effects on work performance through service quality. Accordingly, all of the workers engaging in the hotel business, including board of directors, ordinary managers and staff working at the food and beverage section, are highly required to recognize how keenly important service quality is for the hotel business.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.555-562
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• 2014

To perform performance-based seismic design of buildings, it is necessary clear goal for usage and stability after an earthquake. To clear this goal, it requires a review of the constituent material of the building and, in particular, a member used as an indicator of the residual strain is useful. There are more usage of prestressed concrete because of prestressing steel witch has characteristics of the origin-oriented. In this study, the goal is estimating of residual strain on the prestressed concrete beam member. The expression for angle of deformed prestressed concrete beam member was obtained from using of curvature on the critical section and the equivalent plastic hinge length based on 'equivalent plastic hinge length method'. Considering the balance of strength and deformation conditions, suitable analysis values were derived from 'split Element Method'. Through various parametric studies, various factors affecting the residual strain were decided. Based on the results of this study, it is expected many researches will be proceed in the future.

• Journal of Convergence Society for SMB
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• v.1 no.1
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• pp.1-8
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• 2011

With a sample of 147 Korean small and medium size companies, this study examined the relationships among degree of information orientation, corporate culture, degree of information management implementation and selected business performances in the process of implementing IMS(Information Management System). Information orientation is defined as company-wide understanding and implementation of the underlying philosophy, principles, approached, and tools of information improvement programs. It is assumed that successful implementation of information improvement programs requires a information-oriented mind-set of the employees. It is also assumed that successful implementation of information improvement programs require strong support from s corporate culture that emphasizes continues improvement. Adopting the competing values model of Quinn and McGrath(1985), corporate culture is classified into 'flexible' versus 'controlled culture' and 'outer-directed' versus 'inner-directed culture'. This study examined how such fitness influenced the implementation of information innovation programs and business performance. Implementation of information innovation programs was measured through various factors, such as leadership, strategic information planning, human resources focus, customer and market focus, process management, and information analysis and application. Business performance was measured through non-financial performance measuresm such as employee results, process results, information results, and customer results, and through perceived financial performance measures.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.139-155
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• 2013

The purpose of this research is to study the impact of a consulting-recipient company's organizational characteristics have on consulting performance based on a case study of M manufacturing company that received HR consulting. Noticing that the subject company received HR consulting, consulting performance was evaluated in terms of two variables, HR effectiveness and organizational commitment, and the research focused on analyzing HR system improvement and change in awareness of employees. The result showed that all lower factors that describe organizational characteristics - closeness, delegation of responsibilities, ethical management, communication and shared values - had statistically positive impact on HR effectiveness at significance level p<.05. Also, the higher the HR effectiveness, the higher the positive impact on organizational commitment improvement. Moreover, it was shown that all lower factors in organizational characteristics had positive impact on overall consulting performance. Accordingly, the research concludes that, in order to improve consulting performance, i.e., HR effectiveness and organizational commitment, for blue collar workers, the company needs to create a family-oriented and closely-knit working environment, establish rules and systems to delegate responsibilities appropriately, actively promote ethical management and provide strategic activities to facilitate effective communication.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.340-344
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• 2011

Thermoelectric bismuth telluride ($Bi_2Te_3$) films were deposited on $4^{\circ}$ off oriented (001) GaAs substrates using a modified metal organic chemical vapor deposition (MOCVD) system. The effects of substrate temperature on surface morphologies, crystallinity, electrical properties and thermoelctric properties were investigated. Two dimensional growth mode (2D) was observed at substrate temperature lower than $400^{\circ}C$. However, three dimensional growth mode (3D) was observed at substrate temperature higher than $400^{\circ}C$. Change of growth mechanism from 2D to 3D was confirmed with environmental scanning electron microscope (E-SEM) and X-ray diffraction analysis. Seebeck coefficients of all samples have negative values. This result indicates that $Bi_2Te_3$ films grown by modified MOCVD are n-type. The maximum value of Seebeck coefficient was -225 ${\mu}V/K$ and the power factor was $1.86{\times}10^{-3}\;W/mK^2$ at the substrate temperature of $400^{\circ}C$. $Bi_2Te_3$ films deposited using modified MOCVD can be used to fabricate high-performance thermoelectric devices.