• Journal of Power Electronics
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• v.16 no.1
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• pp.173-181
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• 2016

In this paper, a new technique for harmonic optimization in cascaded H-bridge 7-level inverters is proposed. The suggested strategy is based on minimizing an objective function which simultaneously optimizes the converter utilization and Total Harmonic Distortion (THD). The Switch Utilization Ratio (SUR) is formulized for both the phase and line-line voltages of a 7-level inverter and is considered in the final objective functions. Based upon the SUR formula, utilization ratio enhancement will reduce the value of feeding DC links, which improves the efficiency and lifetime of the circuit components due to lower voltage stresses and losses. In order to achieve more effective solution in different modulation indices, it is assumed that the DC sources can be altered. Experimental validation is presented based on a three-phase 7-level inverter prototype.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.10 no.2
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• pp.214-222
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• 2003

Purpose: This study was done to investigate sleep patterns and utilization of the charcoal eyepatch In high school students through a survey research. Method: The participants in this study were 80 students in a high school in Seoul. The period of data collection was from July 1, 2002 to 15, 2002. The research instruments used in this study were the measures of sleep and SPSSWIN 10.0 Program was used for data analysis. Result: The students went to bed after 12 p.m., but many of them easily fell asleep within 5 minutes. They woke up quite early at around 4 to 6 o'clock in the morning but remained in bed 1 hour. Satisfaction with their sleep was the response for 38.8% of the students. While 77% napped, they generally did so in the afternoon and 38.8% napped for half an hour. As for quality of sleep, 2.5% of the students could not sleep deeply, and 21.7% woke frequently during sleep. Their sleep environments were calm and comfortable, and they turned off the light when sleeping. The utilization of the charcoal eyepatch was effective for sleep, fatigue and powerlessness in high school students. Conclusion: Utilization of the charcoal eyepatch was effective for sleep in high school students and while the utilization of charcoal is recommended in life, the effect of charcoal must be testified through research.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.149-156
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• 1990

In DC electric railway systems, the feeding currrnt is not permitted to flow backward in almost all the substations and the pantograph voltages at the regenerating cars rise extremely by the voltage drop of the resistance of the feeder line. In order to prevent the overrise of the pantograph voltage in power regenerating cars, the squeezing circuits for the regenerative current are equipped and this leads to double losses, which are an extra worn-out of the brake-shoes and an ineffective use of regenerative power. In this study, the insertion of resistors in the feeder line system is proposed as a possible method for the effective utilization of the regenerative power in the electric railways. Also it is investigated how the output voltages of substations affect the effective use of regenertive capability. The investigation results show that the energy savings and the reduction of the worn-out of the brake-shoe can be achieved at the same time by the insertion of resistors in the feeder line system.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.149-169
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• 2011

As the number of smart phone users increases, many organizations begin to adopt social media rapidly to diversify communication channels with customers. Specifically, twitter, which supports instant and two-way communications between users and between organizations and users, has been adopted by many organizations as an efficient way not only to identify new customers but also to retain existing customers. However, little attention has been given to the issue on how organizations can effectively use twitter to improve customer satisfaction. To explore the issue, this study proposes two major dimensions, customer participation and organization resource utilization, which should be considered in building a utilization strategy for twitter in organizations. We then develop four different combinations along with these dimensions-follow, mention, retweet, and review types. Based on case studies of 27 organizations that use twitter, we evaluate the degrees of customer participation, resource utilization, and customer satisfaction, and examine matching or mismatching of the adoption purpose of twitter and its actual utilization. The study results reveal that organizations in the matching group show higher customer satisfaction that those in the mismatching group. This study sheds new light on twitter research by developing a new conceptual framework and using a case study approach to explore the relationship between the utilization strategy of twitter and customer satisfaction.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1369-1373
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• 2003

ACE (Angiotensin-I converting enzyme) inhibitory peptides derived from foods are thought to suppress high blood pressure by inhibiting ACE. We tried to make efficient production of the ACE inhibitory hydrolysate from egg albumen. A hydrolysate digested by neutrase presented the highest ACE inhibitory activity ($IC_50\;value=256.35{\mu}g/ml$) and the proper proteolysis was occurred by 1.0% enzyme addition and 4 h incubation at $47^{\circ}C$. Antihypertensive effect of neutrase hydrolysate was investigated in spontaneously hypertensive rats (SHR, n=5). Systolic blood pressure (SBP) was decrease by 6.88% (-14.14 mmHg, p<0.05) at 3 h after oral administration of 300 mg/kg body weight, and by 13.33% (-27.72 mmHg, p<0.05) by emulsified hydrolysate. These results showed that it is very effective to utilize egg albumen as a protein source for the production of ACE inhibitory peptides. However, further studies are required to investigate the methods to increase recovery yield and the isolation of active peptide is necessary for determining its sequence responsible for ACE inhibitory activity.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.369-377
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• 2012

Recently, development of IT technology and enhancement of spatial information technology increases the necessity about effective technology of damage investigation in the area of disaster prevention. Quick damage investigation is necessary to deal with the natural hazard and plan the recovery. To do this, UAV is the useful mean for quick damage investigation. In this study, it was evaluated based on UAV that utilization of real-time aerial monitoring system for effective damage investigation of natural hazard. Accuracy analysis was implemented to evaluate the application of this system. And utilization of damage investigation was evaluated based on the domestic regulations that is appled the system according to the type of hazard. As a result, damage investigation was possible about house, farmland, agriculture and forestry facilities and public facilities. Henceforth, it will be effectively possible to inspect damage for natural disaster and to establish restoration plan through utilization of acceptable image data by Real-time Aerial Monitoring System in real various natural disaster.

• Journal of Family Resource Management and Policy Review
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• v.9 no.1
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• pp.131-146
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• 2005

The farming type in Korea is predominantly a small farm managed by family members. This study mainly examines the current usage of the website of family farms as a management tool for small farm business and discusses the strategies for effective utilization of the website. A county that currently employs governmental project of information system was purposely selected. Among all the websites operated by small farm businesses in that county, websites of which purpose is introduction of the business, advertisement, or e-business were included for analysis; it yielded total seven websites, The study was conducted with two phases; on-line website analysis and interview with business owners. The websites were analyzed based on four categories; content, interface, design, and site management. With regard to the content of the websites, the lack of connection between domain names and product names was found. Moreover, the problem relevant to site management was shown as low utilization of bulletin boards and delayed upload of new information. However, design and interface were comparatively well presented. Business owners reported that the motivation to initiate the websites was mostly supports from the governmental project for the agricultural information system. The barriers to effective management of websites were found i) business owner's misinterpretation of business website with e-business ii) very limited opportunity for website management education in small farm business, and iii) lack of regional infrastructure for information system. Based on the findings, this study suggests as followed; i) construction of infrastructure should be preceded to make effective management for websites; ii) education for website management should include small business management strategies as well as computer skills, iii) the education should be provided in diverse ways considering subject's characteristics iv) small farm business owners should be informed that their websites could play a role only to provide information about the products and hand over the practical load for e-business to retailing web sites such as portal shopping mall; and v) wives' participation should be encouraged.

• Journal of Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.419-430
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• 1988

This study was performed in a rural community, Kanghwa county which was introduced to a regional medical insurance pilot program in 1982. The purposes of this study were, firstly, to observe the changes in ambulatory care utilization in the three years 1982, 1983 and 1987 : secondly, to analyse factors which convert perceived medical care needs to effective medical care demand. During the three periods, a serial interview survey was performed to determine the changes in medical utilization before and after the regional medical insurance program implementation. The number of subjects was 3,356 persons in the year 1982, 3,705 in 1983 and 2,745 in 1987. The results of the study were as follows : 1. Total ambulatory care utilization rates per 100 persons during a 2-week period were 23.6 in the year 1982, 21.8 in 1983, and 29.3 in 1987; and physician visit rates were 6.1 in 1982, 11.7 in 1983, and 14.9 in 1987. Thus, compared to the total utilization rate there was a definite increase in physician visit, and during the study periods there was a decrease in drug store visits whereas an increase in hospital or clinic visits was noticed. 2. The rates of effective demand for medical care need were 70.7% in 1982, 70.5% in 1983 and 75.9% in 1987 : and the rates of patients who visited physicians were 20.2% in 1982, 42.8% in 1983 and 35.6% in 1987. Thus, physician visits increased sharply by introducing the medical insurance program, but after the latent medical care demands were fulfilled, there was a slight decrease in the physician visits. 3. The number of acute symptoms and the number of chronic symptoms were common determinants of total ambulatory care utilization and physician visits. Besides the medical care need factors, age in 1982, sex and accessibility in 1983, and accessibility in 1987 were statistically significant determinants of the total utilization ; sex and accessibility in 1983, and education in 1987 were also statistically significant determinants of the physician visit. 4. For persons with perceived acute symptoms during the 2-week periods, accessibility in total utilization and age in physician visits were common discriminating factors of ambulatory care utilization in the three years, and education and income were also statistically significant variables. For persons with perceived chronic symptoms, occupation and income were statistically significant discriminating variables commonly observed in total utilization and physician visits.

• Journal of Korea Technology Innovation Society
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• v.19 no.2
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• pp.358-394
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• 2016

In Korea, co-utilization of research equipments has been low, even though co-utilization policies for them have been implemented for a long time. This situation results because the policy formation and implementation for the co-utilization of research equipments have been conducted from the perspectives of the policy maker not from those of the researchers and equipment managers. Therefore, this work has been conducted for analyzing the current state of co-utilization of research equipments as well as for discussing the future developments of its more co-utilization in the basic research programs by adopting the bottom approach in policy implementation theory. The research shows that firstly principal investigators, especially professors in universities, have placed a relatively low priority on the co-utilization of research equipments, secondly implementation resources such as high quality technicians and affordable budget for co-utilization are scare, thirdly incentives for the activation of co-utilization in the stage of daily operation of research equipments are lacking. As a result, the study tries to develop a more economic means and information tools for the promotion of co-utilization of research equipments in the perspectives of bottom-up approach in policy implementation theory.

• Journal of the Korean Professional Engineers Association
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• v.32 no.1
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• pp.90-98
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• 1999