• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.353-358
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• 2020

In the case of a general spiral inductor, the orientation of the port is affected as it has an asymmetric structure. In this paper, a single-layered spiral inductor that can have a symmetrical structure is proposed, and the simulation and frequency characteristics are analyzed. The general spiral inductor shows a large difference in frequency-inductance characteristics, frequency-quality factor characteristics, and self-resonant frequency according to the standard of the port, while the proposed symmetric spiral inductor has an inductance of 2.7nH, a quality factor of about 7.86, and a self-resonant frequency of about 14.1GHz without changing the port. Compared to the general spiral inductor having a large difference depending on the port, it was confirmed that the influence on the port direction was small. However, it was confirmed that the mutual inductance decreased compared to the occupied area of the coil, resulting in a low inductance, and the resistance of the coil increased more than the increase in the inductance, and the quality factor was also lowered. In the future, it is expected that inductance and quality factor can be improved through a 2-layer symmetrical spiral structure.

• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.457-466
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• 2003

The aim of study was to investigate the effect of flow, specimen geometry and adhesion on the measurement of linear polymerization shrinkage of light cured composite resins using linear shrinkage measuring device. Four commercially available composites - an anterior posterior hybrid composite Z100, a posterior packable composite P60 and two flowable composites, Filtek flow and Tetric flow-were studied. The linear polymerization shrinkage of composites was determined using 'bonded disc method' and 'non-bond-ed' free shrinkage method at varying C-factor in the range of 1∼8 by changing specimen geometry. These measured linear shrinkage values were compared with free volumetric shrinkage values. The viscosity and flow of composites were determined and compared by measuring the dropping speed of metal rod under constant load. In non-bonded method, the linear shrinkage approximated one third of true volumetric shrink-age by isotropic contraction. However, in bonded disc method, as the bonded surface increased the linear shrinkage increased up to volumetric shrinkage value by anisotropic contraction. The linear shrinkage value increased with increasing C-factor and approximated true volumetric shrinkage and reached plateau at about C-factor 5∼6. The more flow the composite was, reduced linear shrinkage was measured by compensation radial flow.

• Korea Journal of Hospital Management
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• v.23 no.4
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• pp.40-52
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• 2018

The purpose of this study is to identify medical consumers' hospital selection factors in response to the rapidly changing environment of medical industry. For that purpose this study classified consumers' hospital selection factors into three categories such that human factors including expertise, reliability, empathy; system factor including, convenience, differentiation, efficiency; and facility factor including tangibility, accessibility, and location, based on the previous studies and the results of a preliminary survey of the patients of a small private hospital. The nine factors were further divided into 23 more specific attributes. Then, an online survey was conducted to measure the perceptions of the 23 attributes by the medical consumers over the age of 20. The analysis of the survey data using Kano model and Timko model indicated that 14 of the 23 attributes were classified as attractive factors, eight attributes were or classified as, one-dimensional factors, and one attribute, doctors' educational background, was classified as indifference factor. Of the 14 attractive factors, "unique and differentiated services related to medical treatment" and "distance from home to hospital" had the highest customer satisfaction coefficients. Of the eight one-dimensional factors, "kind treatment," "providing adequate explanations," "accuracy of diagnosis," and "cleanness of facilities" had the highest customer satisfaction coefficients as well as the highest dissatisfaction coefficients. The findings indicate that these six attributes are the most basic and most impactful attributes that hospitals must manage strategically to improve their service quality and attract more medical consumers to their hospitals.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.4
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• pp.358-369
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• 2000

Shielded metal arc welding machines with AC transformer have been widely used for thin-plate welding applications. Because of being bulky, heavy and of tap-changing property, so the SMAW's are changing to new power electronic circuits such as inverter circuit in order to reduce the system size and also to improve the welding performances at input output sides. The PWM inverter arc welding machine with diode rectifier has better output welding performances but it is has the plentiful harmonics and the lower input power factor. To solve these problems, input current-controlled scheme is considered for PWM inverter arc welding system, and then total input power factor is maintained to be more than 99%. Also a new combined control is proposed which can control both instantaeous welding output voltage and current under constant power condition, and as a result the variations of instantaneous current and voltage can be reduced to very narrow range in the V-I curve relationship, and hence the variance of welding current and voltage become so reduced. In addition the spatter generated during welding process is greatly reduced up to 70%. And the overall effiency can be improved up to 10%, which becomes higher when the load is lower.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.260-276
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• 2021

Wetlands are constantly affected by internal and external environments that make up the wetlands, and these effects make wetlands change. East Asia countries where about 15% of Ramsar's registered wetlands are located, is valuable conservation area due to various wetland types and biodiversity. However, due to climate change and other factors, the total area of wetlands has been reduced and biodiversity have been damaged. To mitigate these problems and to manage wetlands efficiently, it is important to identify the factors that change wetlands and to identify how each factor affects them. In this study, we conducted a wetland-related literature analysis in East Asia to derive factors that affect the changes in wetlands, and analyzed the relationships among the factors. Finally we presented research directions considering wetland change factors. In most of the East Asia countries, it was found that there is deficiency in research studies about extraction in direct factors and water-energy infrastructure, tourism & recreation in indirect factors. Also, we presented the necessity for future research using the result between connectivity & relationship analysis and indirect drivers of change and their influence on direct drivers of change. The results of this study could contribute to the establishment of an R&D cooperation system in East Asia region and strengthen wetland management.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.1
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• pp.37-44
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• 2012

This paper describes energy loss in a pipe line of refuse collecting system. Analysis of energy loss in a pipe line is the decisive factor in a design of refuse collecting system. Using the results of energy loss analysis, we can determine the power of turbo-blower. The flow characteristics of the pipe line with refuse bags were analyzed by three-dimensional CFD. The refuse bag is modeled by using the shape obtained from profile measurement. Friction factors were calculated with changing the refuse bag size, mixing ratio and Reynolds number. And drag coefficients were calculated using the CFD results. From the results we can calculate energy loss in a pipe line of refuse collecting system and predict the capacity of turbo-blower.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.853-854
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• 2012

Recent logistics environment is changing rapidly. A wide variety of customer requirements, IT skills development and the globalization of enterprise management is a major factor. In particular, Logistics cost savings is an important factor in ensuring the competitiveness of enterprises. As a result, companies gain competitive advantage for logistics distributed within the organization to manage resources efficiently integrate ERP enterprise resource management program, a new tool for companies to be competitive, attention was given. In this paper, work orders, purchasing, production management and quality management to provide a systematic and efficient logistics of ERP implementation strategy is proposed.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.56-63
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• 1999

In this paper, we realize the active PFC(Power Factor Correction) system of BF (Boost Forward) converter with PWM-PFM control technique to control DC output voltage, and to control the input current with sinusoidal wave synchronized by the converter and inverter using power switching element, FET and IGBT. The control circuit of the suggested Boost converter is implemented with a microprocessor 80C196. After making the ratio of output voltage to current as 50V/1A and the duty ratio greater than 0.5. When input voltage is 30V and boost inductance is 1.1mH. We control the voltage changing rate according to the variation of load resistance using a PWM-PFM control technique. And finally we prove experimentally. PF can be improved up to 0.96 using the current shaping technique.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.11
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• pp.596-602
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• 2015

In this study, experiments using bioelectronic signals and questionnaire surveys were carried out in learning conditions when temperatures changed from low- and high-uncomfortable to comfortable. As a result, the stress factor Photoplethysmography (PPG) decreased, while the Root Mean Square of Standard Deviation (RMSSD) of PPG increased when the indoor temperature was changed from low- or high-uncomfortable to comfortable. Additionally, the absolute power of the ${\alpha}$-wave in the brain increased. According to the analysis of the association between the questionnaire and bioelectronic signals, the standard deviation of the stress factor as measured by pulse was closely related to the result of the thermal sensation questionnaire. In addition, it was found that the concentration on studying improved under comfortable temperatures when compared to uncomfortable temperatures.

• Strategy21
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• s.31
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• pp.120-141
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• 2013

Korea, China, and Japan forms triangle structure which mixed complicatedly on the history and maritime territorial disputes. Nationalism lies on the basis of triangle structure, and it is a main factor which increase tension and conflicts among three countries. Considering dynamics of changing nationalism circumstance, Ieodo issue needs to prepare active countermeasures which considers cope with nationalism confrontations. The aim of this article is suggests preparations of active countermeasures cope with nationalism provocative actions. First, I will specify nationalism as a factor of territorial dispute, and review characters of Ieodo issue. Second, I will analyse China's nationalism to Ieodo through analysis of China's media contents and coverage trend of Ieodo issue (2006~2008). I will suggest necessity of active defense measures coup with China's nationalism, basis of these analysis. As a result, China's nationalism might be a criterion which measures of China's desire for Ieodo. Stimulating Ieodo coverage of China's state media can be a criterion which predicts China governments's for Jurisdiction of Ieodo. We need active measures coup with China's nationalism Which evolves into a much more bold and assertive.