• Journal of Power Electronics
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• v.14 no.5
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• pp.1038-1046
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• 2014

Lithium-ion batteries are widely used in hybrid and pure electric vehicles. State-of-charge (SOC) estimation is a fundamental issue in vehicle power train control and battery management systems. This study proposes a novel model-based SOC estimation method that applies closed-loop state observer theory and a comprehensive battery model. The state-space model of lithium-ion battery is developed based on a three-order resistor-capacitor equivalent circuit model. The least square algorithm is used to identify model parameters. A multi-state closed-loop state observer is designed to predict the open-circuit voltage (OCV) of a battery based on the battery state-space model. Battery SOC can then be estimated based on the corresponding relationship between battery OCV and SOC. Finally, practical driving tests that use two types of typical driving cycle are performed to verify the proposed SOC estimation method. Test results prove that the proposed estimation method is reasonably accurate and exhibits accuracy in estimating SOC within 2% under different driving cycles.

• Journal of Information Technology Applications and Management
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• v.27 no.4
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• pp.63-83
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• 2020

Corna Virus is being widely spreaded across the world and accelerating working environments to home-based telecommuting environments rapidly. Many companies, however, are afraid of decrease in productivities due to insufficient technology readiness by new technology environments. Therefore, finding out the influencing factors which improve the productivities in home-based telecommuting environments is a very important research issue. This study suggests several influencing factors such as technology readiness, technostress, and control behavior and a research model by literature review. To verify the model a total of 204 questionnaires are collected from office workers who are currently utilizing home-based telecommuting. The statistical analysis show that technostress influences negatively to productivities. In addition, moderating effect analysis show that control behavior affects negatively and technostress positively to alleviate the technostress. The result is expected to provide a theocratical framework for further related research and practical guidelines for improving productivities in home-based telecommuting environments.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.17-27
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• 2014

This research extends the research stream of technostress by incorporating age and gender as moderators of user perceptions in the workplace. Individual reactions toward technostress were studied throughout the past decade. However, changing demographic patterns have led to an increasingly older workforce. Gender effects in individual reactions toward technological stress differ based on age. Specifically, gender differences in technology perceptions became more pronounced among older workers, but a unisex pattern of results emerged among younger workers. The results from this study suggest that the factors of technostress is changed by gender and age. In light of these findings, theoretical and practical implications for researchers and practitioners are discussed.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.127-140
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• 2014

This study is performed to measure a performance of IMS using Delone & McLean's Information Success Model as a practical analysis for IMS implementation and their effects. For this, I reviewed the pre-research literatures to attain the measurement factors for IMS implementation and information system success model. For inspecting the hypotheses, answered the questionaries to the IMS managers. The results are as follows: the first, to improve the user's will, they have to focus on the service quality. The second, to improve the user's satisfaction, focus on the system quality. Finally, which affect on the performance is user's will rather than satisfaction.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.37-53
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• 2014

Audits by local governments help to improve local governments's internal control, diagnose their policies, increase their administrative performance and prevent any Policy errors. But the specialty level of the self-authority audit & inspection is low level. It comes from frequent job rotations which results in disposition of unskilled employees instead of ones having majoring knowledge and practical experience. In order to overcome the aforementioned problems and strengthen the function of the self-audit in local governments, we suggested a new system as a solution by considering various audit environments. This study is to find the problems of local Audit and suggest the new system of self audit evaluation system. Electronic self-authority and inspection system is strengthen the self-authority audit & inspection and ultimately will be making strength the effectiveness of local government performance.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.733-745
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• 2013

This article aims to look into the education policy of the civilian government, the practical government, the participatory government and the government of the people after the military government, and then to investigate characteristics and problems to neo-liberalism, which was an common education innovation policy of past government. This study tries to suggest a far-sighted national policy of education the present government should orient. Futhermore, the article presents 'humanistic philosophy of education' as a new paradigm of a future education. This means balanced humanistic education policy, not disintegrated education in which excellence and equality take different paths.

• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.113-121
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• 2005

In this study, those previous research works are reviewed and summarized in various contexts, and this paper also describes the results of an empirical study done for the sample business workers in Korea, analyzing SQC and consumer's value. The surveyed data are statistically analysed to examine the relationship between SQC acquisition and consumer's value in the lodging industry, considering additional factors of business types of companies as well as the consumer's using purpose of service facilities. The important findings of the study can be summarized as follows: First, the business types of companies is an insignificant factor on the consumer's value by the quality certificated services, while the using purpose of service facilities(Hotel and Pension) is an significant factor. Second, the descriptive result is shown that consumers are willing to pay 21.47～31.24 % more than the un-certificated services for quality-certificated services. On the basis of these findings, some practical implications can be drawn for the effective management of the lodging industry. When a firm decides to establish a business plan, it should be considered the using purpose of service facilities.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.72-72
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• 1993

Among the various diagnostic methods for the voice disorders, video laryngo-stroboscopy is one of the most practical techniques for clinical examination of the vocal fold vibration. It provides valuable informations about the nature of vocal folds' vibration, the extent of pathologic change and data recording for analysis. To obtain the stroboscopic characteristics of several voice disorders, and apply those informations to the diagnosis and management of disorders, we reviewed the stroboscopic findings obtained from the patients with voice disorders at Voice laboratory, the Institute of Logopedics and Phoniatrics form April 1992 to March 1993.

• The Journal of Information Systems
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• v.23 no.1
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• pp.185-202
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• 2014

ERP, a typical enterprise application, helps companies to increase their productivity and to support their decision makings. ERP is composed of diverse functions that are optimized under PC environment, whereas the ERP applications on a mobile platform have many constraints such as a small screen, limited resolution, and computing power. Because all the functions of a ERP legacy system are not required for ERP on a mobile device, the core functions of the ERP system should be selected to increase system efficiency. In this study, two main methods were used; interviews and log analyses. The end users using a ERP system were interviewed for their perceptions, and log data analyses were made for the hitting number of specific ERP functions. The differences between the actual usage based on log data and users' cognitive preferences about ERP functions were analysed. Finally, the functional differences between users' perception and actual usage were suggested for some practical implications.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.77-83
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• 2015

This study, according as the limits on learning and unsatisfaction about e-learning are emerging and the structural contradictions of the e-learning industry are continuing, was carried out to present the policy alternatives for solving these. As a means for overcoming the limitations of e-learning and the healthy growth of e-learning industry, this study presents the application of Bigdata in e-learning and proposes several practical challenges of policy. Policy action plans are technology development support, professional manpower support, SME application support, legal improvement.