• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.292-298
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• 2003

Most of the three phase inverters for adjustable speed drive of AC machines are equipped with two or three current sensors for measurement of three phase current. One method to reduce the number of current sensors is that single current sensor measures the DC link current, then three phase current is reconstructed using the measured value and the switching status. To improve the measurement accuracy, switching state should be maintained for more than minimum switching time. Many papers have been published, which focused on the readjustment of pulse width and compensation of voltage distortion. Those methods are suitable for space vector modulation. But there are some difficulties in applying these methods to carrier-based PWM which is widely used in industry. In this paper, new current measurement method and voltage compensation method are proposed which are suitable for carrier-based PWM, then, the validity of proposed method is confirmed through experiment.

• Journal of The Korean Association For Science Education
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• v.35 no.3
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• pp.465-475
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• 2015

The purpose of this study is to analyze the results of physics (optics) in nationwide standardized assessment and to investigate middle-school students' characteristics of achievement by using an option response rate distribution curve. For this purpose, we analyzed the 10 optics problems from the National Assessment of Educational Achievement (NAEA) items for middle school science subject conducted in 2010-2013. The results of this study are as follows; First, students showed a little higher achievement in optics than classical mechanics and electromagnetism. Second, students achieved significantly worse in 'formation of image' in 'light' part and 'variation of phase in propagation of wave' in 'wave' part. Third, students showed a context-dependent problem solving strategy and result. Additionally, we suggested some implications about the readjustment of some optics concepts level of national science curriculum, the need for teaching and learning strategies for basic level students, and the need for teaching and learning strategies focused on the realistic context.

• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.81-90
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• 2007

The life changes of TMJ patients were evaluated through the Social Readjustment Rating Scale (SRRS) questionnaire. 33 recurred TMD patients and 32 new TMD patients were studied at the TMJ clinics, Department of Oral Medicine, PNUH from September 2005 to August 2006. The obtained results were as follows: 1. The life change unit(LCU) totals in the recurred TMD patients were significantly higher than those in the control subjects, during the $7{\sim}12$ months before presentation for the hospital. 2. The life change unit(LCU) totals in the recurred TMD patients were higher a little than those in the control subjects during a year before presentation for the hospital. 3. There was no significant difference in LCU totals and life events between the recurred TMD patients and the control subjects by age. 4. There was no significant difference in LCU totals and life events between the married group and unmarried group in the subjects.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.11 no.1
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• pp.39-45
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• 2000

Background and Objectives : Accent method is one of holistic approaches for behavior readjustment of voice therapy The aim of this study is to evaluate the efficacy of the accent method of voice therapy for the patients who have no improvement after LMS. Materials and Methods : Of the patients who had been undergone LMS during the period from Jan. 1999 to Dec. 1999, medical records of 38 patients who had not been improved were studied retrospectively. 19 patients(treatment group) were applied accent method and the other 19 patients(control group) refused voice therapy. The voice of all the patients of both group were analysed with CSL and Aerophone II programs in pre- and post operative period. The voice of treatment group were analysed with Visi-Pitch II program before the application of accent method and after the completion of accent method. Then, the results were compared using paired t-test. Results : The results of voice analysis were not different statistically between pre- and postoperative examination in both group. After application of accent method in the treatment group, fundamental frequency(F$_{0}$) of male, relative average pertubation, and shimmer were revealed significant differences(p＜0.01), and decrease in grade(G) scale and roughness(R) scale were statistically Important in perceptual analysis using GRBAS criteria(p＜0.01). But $F_0$ of female, maximal phonation time and S to Z ratio were not revealed significant differences. Conclusions : Accent method of voice therapy may be as a supplement- ary therapy in the patients who were not improved after surgery.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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• pp.147-157
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• 2013

Rice is a main crop and rice field is the most important farmland in Korea. This study was conducted to propose the methodology assessing impact and vulnerability on rice production by climate change at the regional and national level in Korea. We evaluated a vulnerability of rice paddy according to the outbreak of a main disease and pest of a rice plant. As results, Jeju-do, Gyeongsangnam-do, and Jeollanam-do were more vulnerable area than others. In contrast, the southern central region including Gyeonggi-do was less vulnerable than others. The vulnerable index was significantly higher in 2050s (0.5589) than in present (0.3500). This result showed that the vulnerable to the disease and pest enlarge in the future. The adaptive capacity highly contributed to the vulnerability assessment index. The daily maximum temperature of June and the daily average temperature from May to August also contributed the climate exposure index. The area of occurring sheath blight, rice leaf blast and striped rice borer was related to the system sensitivity index. The ability of water supply (readjustment area of arable land per paddy field area) and rice production technique (rice yield per hectare) were the highly contributed variables to the adaption capacity index.

• Journal of the Korean housing association
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• v.24 no.5
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• pp.57-67
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• 2013

The purpose of this study is to find out distributional principles of the shop-houses in residential district through physical composition of residential area. Through the research that are based on literature and field survey, it analysed the relation between physical composition of residential area and the shop-houses of selected four sites under similar urban condition where land readjustment project were held. The consequences of this study are summarized as follows; 1) A road that is not penetrating the inside a residential area is seemed to have low occupancy of shops comparing to other roads with similar hierarchy. And the shops functions as convenience facilities. It can be inferred from the statement above that even a road with higher hierarchy is not easy to form commercial area if without penetrating the residential area. 2) According to the size and the arranged method of Inner blocks of residential area towards major roads, distribution of shop-houses appear to be different. In other words, when shop-houses are located along the roads, the proportion of shop was higher than when located perpendicular to the roads. 3) When the number of average lots are little and the size of block is small, usually, street ratio and the number of corners gets higher, which eventually increases the number of shop-houses.

• Journal of Korean Society of Rural Planning
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• v.24 no.1
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• pp.113-127
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• 2018

This study comprehends that the landscape of Ipsan Village is the accumulated output of the landscape management and social behavior by the historic personages through the reference research and field surveys. And the study sorted out the over-layered landscape characteristics of Ipsan Village by analyzing the dispersed landscape elements as follows. First, right before the start of Japanese invasions to Korea(1592-98), Tamjin(耽津) An(安) Family moved into Ipsan and started establishing the a single clan village. At a site with mountain background and facing the water(背山臨水), the village used to be a typical farming one with an organically planned road-system and housing area following the traditional order. However, the landscape has changed drastically since the 20th century with the construction of banks, roads and readjustment of arable land etc. Second, the original landscape, which can be figured out through the 'Gosanjaesibyukgyeong(高山齋十六景)' in the 18th century, shows its harmony with natural landscape: mountain & valley, stream & field, traditional trees, etc, cultural landscape: village, well, spring, etc, and momentary landscape: seasons, time, weather phenomena, sound, behavior, etc. Third, based on the second, 16 natural landscape elements: mountain & stream, planting, etc. and 25 cultural landscape elements: housing spaces, self-cultivation & ceremony spaces, community spaces and modern education & enlightenment spaces were selected and interpreted as landscaping meanings. Fourth, the over-layered landscape which stems from the compositive functions and inter-connectivity of landscape elements which consists Ipsan Village is regarded as 'Natural geographical and Fungsu landscape', 'Rural production and livelihood landscape', 'Confucian ceremony and symbolic landscape' and 'Modern education and enlightenment landscape.'

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.2
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• pp.21-39
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• 1992

Many problems were found out the remarkable unbalance between paddy fields and up-land areas, or between plain and mountainous areas, unreasonable establishing of land consolidaton boundaries without consideration of rural development, lower leverl of construction technology of the roads and canals for agricultral use ad operation and maintenance of them by human power far apart from the ages of high technology, high information and free internationalisation, and too slow progress to overcome the weak agricultural circumstances etc. through the survey in the past executed land consolidation projects. The basic ways for solution of these problems for propulsion of land consolidation project through investigation are summarized as follows : 1. Land consolidation project should be executed to the direction of balanced regional development, laying stress on the upland and mountainous areas in order to carry out the agriculture effectively. 2. the acreage of land consolidation project to be conducted anually should be increased to overcome the serious underdeveloped agricultural development. 3. It should be developed to the way in accordance with the order of land use from the view point of rural integral development including the rural readjustment. 4. The level of the structures of road and canal, the size of standard lot and the grouping of land substitution should be to incraese the productivity of land and labour more than ever and reached to a degree in cope with the age of industrialization, information and free internationalisation. 5. The level of the management of agricultural water use and the maintenace of the various facilities should be developed to be automatization, remote control, central control and information processing instead human work. 6. Land substitution should take a measure of grouping method in accordance with the agricultural plan and farming organization, which can overcome high industrialized society in place of the substition by origin land. 7. Land consolidation project should be planned in order to fulfil a conservative function of ecosystem and resources together with improvement of land and labour productivity.

• Journal of the Korean Regional Science Association
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• v.8 no.1
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• pp.31-50
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• 1992

The aim of this paper is to define major factors influencing land development of each of major uses (residential, commercial, industrial) in the process of rapid urban expansion. The main hypothesis of this study is that land use changing patterns are directed by supply side of land managed to public policies rather than demand side. The graphic analysis is applied to relationships between urban growth and land development process of each use and between land development project managed to public policies and land development process. Public and land development projects and zonning protection seem to be major roles of land supply and main determinants of urban spatial structure. Location factors for land development of each uses are selected in 23 variables. Factor analysis is applied to test correlation between variables in 1971 and 1981. Factor structure between two years is similar, but progressive processing of functional separation is derived such as intensive land use is grouped, different location between residential and industrial use is deep. Dependent variables are standardized to logarithm of land development of each use per unit vacant land in two periods, between 1971 and 1980 year and between 1981 year. Correlation analysis between 6 dependent variables and 23 location factors in each years are applied. Major factors of each use are selected in criteria such as high correlation with dependent variables, low correlation between independent variables and common application in two periods. As the result, major factors for residential land development are Land Readjustment Project (LRP), percent of total zoned area in residential zone, residential floor space density per available area, percent of total area in industrial use; for commercial development is distance to CBD, percent of total area in commercial use, residential floor space density per available area in each year, and volumn rate of industrial use; for industrial use is percent of total area of industrial use is percent of total area of industrial use, Industrial Estate Project (IES), LRP, and distance from CBD. Land development pattern of each use between two periods are slightly different. So 6 equation is derived from appling backward method of regession. Adjusted multiple R squares of all is more than 0.5 and those equation is statistically significant and valuable to assist urban land use forecasting.

• Journal of Korea Water Resources Association
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• v.48 no.12
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• pp.1037-1049
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• 2015

The most of natural disasters that occur in North Korea are flood, typhoon and damage from heavy rain. The damage caused by those disasters since the mid-1990s is aggravating North Korea's economic difficulties every year. By recognizing the seriousness of the damages from the floods, the North Korean government has carried out the river maintenance, farmland restoration, land readjustment and afforestation projects since the last-1990s, but it has failed preventing the damages. In order to estimate the degree of flood risk regarding damage from chronic floods that occur inveterately in North Korea, this research conducted an additional simulation for rainfall-runoff analysis to reflect the characteristics of the ungauged area that make foreign countries hard to obtain the hydrological data and do not open the topographical data to public. In addition, this research estimates the degree of flood risk by selecting the factors of the hazard, exposure and vulnerability by following the standards of the Intergovernmental Panel on Climate Change (IPCC).