• Safety and Health at Work
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• v.6 no.4
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• pp.345-352
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• 2015

Background: Goal-oriented communication of risk of hazards is necessary in order to reduce risk of workers' exposure to chemicals. Adequate training of workers and enterprise priority setting are essential elements. Cleaning enterprises have many challenges and the existing paradigms influence the risk levels of these enterprises. Methods: Information on organization and enterprises' prioritization in training programs was gathered from cleaning enterprises. A measure of enterprises' conceptual level of importance of chemical health hazards and a model for working out the risk index (RI) indicating enterprises' conceptual risk level was established and used to categorize the enterprises. Results: In 72.3% of cases, training takes place concurrently with task performances and in 67.4% experienced workers conduct the trainings. There is disparity between employers' opinion on competence level of the workers and reality. Lower conceptual level of importance was observed for cleaning enterprises of different sizes compared with regional safety delegates and occupational hygienists. Risk index values show no difference in risk level between small and large enterprises. Conclusion: Training of cleaning workers lacks the prerequisite for suitability and effectiveness to counter risks of chemical health hazards. There is dereliction of duty by management in the sector resulting in a lack of competence among the cleaning workers. Instituting acceptable easily attainable safety competence level for cleaners will conduce to risk reduction, and enforcement of attainment of the competence level would be a positive step.

• Journal of ILASS-Korea
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• v.26 no.3
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• pp.135-141
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• 2021

High-efficient HEV Engine cooling systems reflects variable coolant temperature because it can decrease the hydrodynamic frictional losses of lubricated engine parts in light duty conditions. In order to safely raise the operating temperature of passenger cars to a constant higher level, and thus optimize combustion and all accompanying factors, a new thermostat technology was developed : the electronically map-controlled thermostat. In this work, various crystalline plastics such as polyphthalamide (PPA) and polyphenylenesulfide (PPS) mixed with various glass fiber amounts were introduced into plastic fittings of automotive electronic controlled thermostat for the purpose of suppressing influx of coolant into the element and undesirable opening during hot soaking. Skirt was installed around element frame of automotive electronic controlled thermostat for improving thermal sensitivity in terms of response time, hysteresis and melting temperature. To validate the effectiveness and optimum shape of skirt, thermal sensitivity test and three-dimensional CFD simulation have been performed. As a consequence, important improvement in thermal sensitivity with less than 3℃ of maximum coolant temperature between opening and engine inlet was obtained.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.227-236
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• 2021

This research proposes a modeling and controller design of a three-level boost (TLB) converter for the implementation of maximum power point tracking (MPPT) in the photovoltaic power conditioning system (PCS). Contrary to the output voltage control of the conventional controller, the Photovoltaic PCS requires an input voltage controller for MPPT operation. A TLB converter has the advantage of decreasing the inductor size and increasing efficiency compared with the existing booster converter. However, an optimal controller is difficult to design due to the complexity of the TLB operations, which have two operational modes on the duty ratio boundary of 0.5. Therefore, the unified linear model equations of the TLB converters, which can be applicable to both operational modes, are derived using linearized solar cell expressions. Furthermore, the transfer functions are obtained for the controller design. The MPPT voltage controller is designed using MATLAB SISOTOOL. In addition, a controller for capacitor voltage unbalancing is described and designed. The simulations and experimental verifications are conducted to verify the effectiveness of the small-signal analysis and control system design.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.88-97
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• 1995

The leaf spring is used in the suspension of most buses and trucks due to its compactness, which reduces the shock-force and the vibration from the road, and increases passenger comfortability and carlife. Of the various kinds of leaf springs, the leaf spring without eyes can be found easily in the heavy duty truck, and has different characteristics to the leaf spring with eyes in the case of large free camber. Because of radius change, the leaf without eyes slips on the supports, which makes the deflection. The difference is due to this deflection. In this paper, we show the general method of characteristic analysis, for example, Pandan method, can be no more applicable to these springs. Thus considering the geometry deflection by slip, we have developed the equation of the characteristic of the leaf spring without eyes and prove the effectiveness of this equation by experiment. From the result, at large camber the slip deflection is large and as camber smaller, this is smaller. At the camber behind some value, the effect of slip no longer influence to the characteristic of leaf springs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.62-70
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• 2007

In this paper, the boost Power Factor Correction(PFC) technique for Direct Torque Control(DTC) of brushless DC motor drive in the constant torque region is implemented on a TMS320F2812DSP. Unlike conventional six-step PWM current control, by properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained, therefore a much faster torque response is achieved compared to conventional current control. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, a pre-stored back-EMF versus position look-up table is designed. The duty cycle of the boost converter is determined by a control algorithm based on the input voltage, output voltage which is the dc-link of the BLDC motor drive, and inductor current using average current control method with input voltage feed-forward compensation during each sampling period of the drive system. With the emergence of high-speed digital signal processors(DSPs), both PFC and simple DTC algorithms can be executed during a single sampling period of the BLDC motor drive. In the proposed method, since no PWM algorithm is required for DTC or BLDC motor drive, only one PWM output for the boost converter with 80 kHz switching frequency is used in a TMS320F2812 DSP. The validity and effectiveness of the proposed DTC of BLDC motor drive scheme with PFC are verified through the experimental results. The test results verify that the proposed PFC for DTC of BLDC motor drive improves power factor considerably from 0.77 to as close as 0.9997 with and without load conditions.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.55-62
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• 2017

This research analyzes the character factor in picture book, so the purpose is to develop the early childhood character program through Nuri curriculum. Picture book is the most familiar media for childhoods, and we are available it naturally in our lives. For this first, we analyze 6 elements(consideration, respect, cooperation, sharing, order, filial duty) in teacher's guide of the Nuri curriculum. Next, consulting the analyzed factors, the 12 picture books which will be utilized this program are chosen by the standard like literary, artistic, educational value. The chosen picture book devised total 12 times education plan to design each 2 times education plan in the factors for teacher's guide of Nuri curriculum. Lastly, it was finally developed through validation process by 2 teachers and 2 the professors of early childhood education. The developed program is needed later field application and It is required of the effectiveness verification after we apply 12 times activities on each age of childhoods for 3 to 5 years od in education field, so it may improve elements like consideration, respect, cooperaion, sharing, order, filial duty as childhoods experience this program personally. Also, this can provide it to teachers in childhood eucation field as study guidance plan.

• International Commerce and Information Review
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• v.19 no.1
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• pp.3-21
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• 2017

As to 'E-Commerce Trade' or 'The Cross Border E-Commerce (CBEC)' which has shown rapid diffusion, Korean government is providing active support on the basis of idea that it has profound impact on increase of export. However, sporadic support propelled by various ministries and agencies are not effective and efficient at all on actual circumstances. Consequently, in order to promote consistency, effectiveness, and efficiency of supporting policy, it is desirable to clarify competent ministry and the duty of cooperation to the other ministries and agencies. For its own sake, it is necessary to amend each existing laws which scattered all over the business territory, or to legislate new enactments. Yet these methods are extremely tough to carry out, therefore, it seems that amending 'Electronic Trade Facilitation Act', which already exist and regulate 'paperless trade' would be a realistic alternative. For the diffusion of Korean CBEC especially export, in this study the author insists that amending this law to promote CBEC is the most reasonable way comparing to other ways with several reference materials.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.509-521
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• 2014

The purpose of this study is to find the correlation between elements of resilience and small group activities in the university, and to explore small group activities as a protective and a positive factor in controlling the stress of college students. As the first part of the study, positive roles of resilience to the stress of college students and the elements that promote the efficiency of resilience are analyzed. The study precedent in detail and four elements of resilience are presented as following; optimistic realism, vitality, ability to control emotion, and interpersonal ability, addressing the faith in God is one of the strong positive factors for developing resilience. Then, this study deals with how the four elements of resilience relates to the characteristics of small group activities. In conclusion, this study suggests Christian universities to develop small group activities because they can develop each of the four elements of resilience of college students. Christian universities have a missional duty and the responsibility to help college students experience real happiness in their lives. Therefore, if Christian universities understand the effectiveness of resilience of college students and find out the correlation between resilience and faith, they can help students not only to live a positive life in their generation, but also to experience the authentic happiness.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.254-269
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• 2009

Corporate business in today's domestic industry focuses on using of culture & arts as internal and external marketing strategies with increases number of business cases of implementing corporate cultural marketing. Despite certain demands for the systematic research of corporate cultural marketing, studies have not been sufficiently developed to meet industrial and academic demands. In some paper, studies on effectiveness of corporate cultural marketing have been examined. But the papers were only limited to a conceptual categorization of corporate cultural marketing. Therefore we intended to study patterns of corporate cultural marketing using actual corporate data and explore inter-relationship across the patterns and characteristics. As a result, Korean firms were categorized into four patterns as below: 1)Duty type, 2)Strategic Partner type, 3)Publicity type and 4)Event type. Also, We found that performance of Strategic Partner type was highest.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2325-2332
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• 2017

Consulting projects such as diagnosis of vulnerabilities of major information and telecommunication infrastructure are increasing, mandatory public information infrastructure assessment (PIA) for public institutions and ISMS (Information Security Management System) The demand for information protection consulting is continuously increasing as the field obeys the law, but the lack of information security consultant is not improving. One reason is that information security consultants are not being developed to meet the increasing demand for information protection consulting. In this paper, we present the case of information protection consulting as a scenario for studying and educating the duty of information security consultant by studying overseas case and domestic case based on standardization and standardization. We propose a problem-based learning (PBL) training method. In addition, we analyze the effectiveness of the PBL - based learning method.