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Study on the Estimation of Long Life Cycle and Reliability Tests for Epoxy Insulation Busway System (에폭시 박막 절연형 버스웨이 시스템의 장기 수명 및 신뢰성 평가에 관한 연구)

  • Jang, Dong-Uk;Park, Seong-Hee;Lee, Kang-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.261-268
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    • 2018
  • The use of electric cable was limited due to the installation time and large space as the increase of power demand and load quantity in side line. In order to solve these problems, the application of busway system which can supply the large current was increasing. But it was lack of methods of performance tests to evaluate the reliability and results of test for busway system. In this paper, we presented items to evaluate the reliability test for epoxy coated busway system with reference to IEC 61349-6. In addition, we proposed items to evaluate the reliability and long term life cycle test for the epoxy coated busway system. The combined acceleration deterioration test that reflects actual conditions of the survey as much as possible was conducted considering both thermal and electrical stresses. The deterioration condition was selected to satisfy fifty years life expectation and the insulation performance verification test of the busway system confirmed the long term life prediction. Furthermore, as test items for reliability assessment of compliance with the environment for the use of temperature, humidity and load current where busway system was installed, thermal overload test, water immersion test, cold shock temperature test and thermal cycle test were performed. And we examined changes in characteristics and abnormality after tests. From results, the test items presented to evaluate performance and reliability of the epoxy insulated busway system were confirmed to be appropriate in this paper, and the performance of the product was also confirmed to be excellent for reliability tests.

The Evaluation of Application to MODIS LAI (Leaf Area Index) Product (MODIS LAI (엽면적지수) Product의 활용성 평가)

  • Ha, Rim;Shin, Hyung-Jin;Park, Geun-Ae;Hong, Woo-Yong;Kim, Seong-Jun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.11 no.2
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    • pp.61-72
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    • 2008
  • Leaf area index (LAI) is a key biophysical variable influencing land surface processes such as photosynthesis, transpiration and energy balance, and is a required input to estimate evapotranspiration in various ecological and hydrological models. The development of more correct and useful LAIs estimation techniques is required by these importance, but LAIs had been assumed in most LAI research through simple relations with the normalized difference vegetation index (NDVI) because the field measurement is difficult on wide area. This paper is to evaluate the MODIS LAI Product's practical use by comparing with LAIs that is derived from NOAA AVHRR NDVIs and the 2 years (2003-2004) measured LAIs of Korea Forest Research Institute in Gyeongancheon watershed (561.12 $Km^2$). As a result, the MODIS LAIs of deciduous forests showed higher values about 14 % and 15~30 % than the measured LAIs and NOAA LAIs. In the year of 2003, the MODIS LAIs in coniferous forests were 5 % higher than the measured LAIs, and showed about 7 % differences comparing with the NOAA LAIs except April. These differences come from the insufficient field data measured in partial points of the target area, and the extracted reference data from MODIS LAIs include the limits of spatial resolution and the error of incorrect land cover classification. Thus, using the MODIS data by the proper correction with the measured data can be useful as an input data for ecological and hydrological models which offers the vegetation information and simulates the water balance of a given watershed.

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A Study on the Important Clause of International Sales Contract (국제물품매매계약(國際物品賣買契約)의 주요 조항(條項)에 관한 연구(硏究))

  • Park, Nam-Kyu
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.18
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    • pp.27-62
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    • 2002
  • The international sale contract is the central contracts in export-import transactions. A good sale contract or set of general conditions of sale will cover all the principal elements of the transaction, so that uncertainties are avoided. The parties' respective duties as concern the payment mechanism, transport contract and insurance responsibilities, inter alia, will all be clearly detailed in the contract. The following key clauses should be included in international contracts of sale and general conditions of sale: ${\bullet}$ preamble ${\bullet}$ identification of parties ${\bullet}$ description of goods ${\bullet}$ price and payment conditions ${\bullet}$ delivery periods and conditions ${\bullet}$ inspection of the goods - obligations and limitations ${\bullet}$ quantity or quality variations in the products delivered ${\bullet}$ reservation of title and passing of property rights ${\bullet}$ transfer of risk - how accomplished ${\bullet}$ seller's warranties and buyer's complaints ${\bullet}$ assignment of rights ${\bullet}$ force majeure clause and hardship clause ${\bullet}$ requirement that amendments and modifications be in writing ${\bullet}$ choice of law ${\bullet}$ choice of dispute resolution mechanism Under most systems of law, a party can be excused from a failure to perform a contract obligation which is caused by the intervention of a totally unforeseeable event, such as the outbreak of war, or an act of God such as an earthquake or hurricane. Under the American commercial code (UCC) the standard for this relief is one of commercial impracticability. In contrast, many civil law jurisdictions apply the term force majeure to this problem. Under CISG, the standard is based on the concept of impediments to performance. Because of the differences between these standards, parties might be well advised to draft their own force majeure, hardship, or excusable delays clause. The ICC publication, "Force Majeure and Hardship" provides a sample force majeure clause which can be incorporated by reference, as well as a hardship clause which must be expressly integrated in the contract. In addition, the ICC Model provides a similar, somewhat more concise formulation of a force majeure clause. When the seller wishes to devise his own excusable delays clause, he will seek to anticipate in its provision such potential difficulties as those related to obtaining government authorisations, changes in customs duties or regulations, drastic fluctuations in labour, materials, energy, or transportation prices, etc.

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Avoidance of Internal Resonances in Hemispherical Resonator Assemblies from Fused Quartz Connected by Indium Solder

  • Sarapuloff, Sergii A.;Rhee, Huinam;Park, Sang-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.835-841
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    • 2013
  • Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

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A Study on the Validation of Effective Angle of Particle Deposition according to the Detection Efficiency of High-purity Germanium Gamma-ray Detector (고순도 저마늄 감마선 검출기의 검출효율에 따른 유효입체각 검증에 관한 연구)

  • Chang, Boseok
    • Journal of the Korean Society of Radiology
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    • v.14 no.4
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    • pp.487-494
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    • 2020
  • The distance between the source and the detector, the diameter of the detector, and the volume effect of the radiation source result in a change in solid angle at the detector entrance, which affects the determination of detection efficiency by causing a difference in path length within the detector. A typical analysis method for calculating solid angles was useful only for a source (60Co) with a simple geometric structure, so in this experiment, the distance between the detector and the source was measured by switching on for up to 25 cm with the reference point of window cap 0.5 cm. In addition, 450 and 1000 ㎖ Marinelli beaker of standard volumetric sources were closely adhered to the detector. For circular point sources co-axial with the detector, the change in the solid angle to the distance from the detector window is equal to half the square radius of the source versus the square radius of the detector, if the resulting relationship of the calculation analysis results in the detector being less than the radius of the source. Since the solid angular difference is 0.5 the result of Monte Carlo is acceptable. The relationship between detector and source distance is shown. Solid angles have been verified to decrease rapidly with distance. Measurement and simulation results for a volumetric source show a difference of ±1.01% from a distance of 0 cm and less than 4 % when the distance is reduced to 5 and 10 cm. It can be seen that the longer distance, the smaller efficiency angle, and the exponential increase in attenuation as the energy decreases, is reflected in the calculation of efficiency. Thus, the detection efficiency has proved sufficient for the use of solid angle and Monte Carlo codes.

Difference in food and nutrient intakes in Korean elderly people according to chewing difficulty: using data from the Korea National Health and Nutrition Examination Survey 2013 (6th)

  • Kwon, Song Hee;Park, Hae Ryun;Lee, Young Mi;Kwon, Soo Youn;Kim, Ok Sun;Kim, Hee Young;Lim, Young Suk
    • Nutrition Research and Practice
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    • v.11 no.2
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    • pp.139-146
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    • 2017
  • BACKGROUND/OBJECTIVES: Chewing difficulty is a factor contributing to a poor nutritional status in the elderly. The aim of this study was to examine disparities in food and nutrition intakes among Korean elderly people with and without chewing difficulty. SUBJECTS/METHODS: This study utilized data from the sixth Korea National Health and Nutrition Examination Survey conducted in 2013. The study subjects included males and females over 65 years of age who were not required to adhere to a special diet due to disease or sickness. They were divided into groups according to their chewing ability. Those who found chewing "very difficult" or "difficult", were combined to form the chewing difficulty group. Similarly, those who found chewing "moderately difficult", "easy", and "very easy" were combined to form the normal chewing group. RESULTS: Of the 999 subjects, 47.7% had chewing difficulties and the prevalence of chewing difficulty was higher in females than in males (P = 0.03) and higher in those 75 years of age and over than in younger individuals (P < 0.001). The chewing difficulty group had a significantly lower intake of fruits and vegetables (P < 0.05) and lower vitamin C and potassium intake than those in the normal group. Comparison of the percentages of Dietary Reference Intakes for Koreans (KDRIs) in the two groups indicated that the intake of most nutrients (energy, vitamin C, thiamin, riboflavin, niacin, calcium, phosphorus, sodium, potassium, and iron) were significantly lower in the chewing difficulty group than in the normal group. In particular, calcium intake was inadequate (51% of KDRIs) in the chewing difficulty group. CONCLUSIONS: The results indicate that chewing difficulty is closely related to food and nutrient intake in the elderly and can result in vitamin and mineral intake deficiencies. It is evident that the care of elderly subjects with chewing difficulty is essential for maintaining a healthy lifestyle.

Effects of Nutrition Education Using Food Exchange System: Changes in Elementary Students' Nutrition Knowledge, Dietary Attitude and Nutrients Intake (식품교환법을 활용한 영양교육의 효과: 초등학생의 영양지식, 식생활 태도, 식이섭취 변화)

  • Kim, Sook-Bae;Choi, Hee-Jin
    • Korean Journal of Community Nutrition
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    • v.13 no.6
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    • pp.922-933
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    • 2008
  • The purpose of this study was to investigate the effects of nutrition education using Food Exchange System on elementary students' nutrition knowledge, dietary attitude and nutrients intake. Nutrition education lessons (40 min /lesson, 4 times), '5 major nutrients and functions', '6 food groups and sources of 6 food groups', 'good choice of snacks and eating out' as class lesson, 'daily needed energy and food exchange units' as individual lesson, were provided to 70 elementary students (4th grade 33 students, 5th grade 37 students) in Jeonbuk Province. We assessed the changes in nutrition knowledge, dietary attitude, food habit using a questionnaire and nutrient intake using 24 hr recall method by nutrition education. In nutrition knowledge, there were significant increases in scores of 'functions of carbohydrate', 'functions of protein', 'functions of lipid', 'foods of carbohydrate', and 'foods of lipid'. In dietary attitude, there were significant increases in scores of 'taking a meal with joy', 'taking a meal at ease', 'taking a meal with sufficient protein intake' and 'taking a meal without spicy foods' by nutrition education. There were significant changes in the type of breakfast and in the frequency of snacks. After education, in type of breakfast, it showed higher number of students ate rice oriented meal than they did before education. and in frequency of snacks, it showed lower number of students ate snacks 'over 3 times' than they did before education. In Carbohydrate : Protein : Fat (CPF) ratio (%), it was significantly changed from 55.8 : 17.7 : 26.6 to 63.6 : 15.3 : 21.1. In evaluation of nutrient intake by Dietary Reference Intakes for Koreans (KDRIs), vitamin A, thiamin, niacin, vitamin $B_6$, calcium, phosphate, iron and zinc showed positive changes in distribution of number of children by intake level. That is, there were significant improvements in intakes of vitamin A, thiamin, niacin, vitamin $B_6$, calcium, phosphate, iron and zinc. These results showed that nutrition education using Food Exchange System for elementary students improved nutrition knowledge, dietary attitude and nutrients intake. It suggest that nutrition education using Food Exchange System may improve dietary behaviors and reduce an incidence of obesity in elementary students.

Investigation of the Acoustic Performance of Music Halls Using Measured Radiation Characteristics of the Korean Traditional Musical Instruments (국악기의 음향방사특성에 따른 국악당의 음향성능조사)

  • Haan Chan-Hoon;Lee Wangu;Jeong Cheol-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.8
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    • pp.469-480
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    • 2005
  • There have been always some difficulties in target setting and conditioning of acoustic performances or the Korean traditional music hall due mainly to the lack of the information on the sound radiation characteristics of Korean musical sources. As the 2nd experiment succeeding the previous study[1], the radiation characteristics of eight typical Korean traditional musical sources were investigated if precision. The selected musical sources were Geomungo, Haegeum (string), Piri, Taepyeongso (woodwind), Buk, Kwaengguari, Jing (drum), and male Pansori Chang (vocal Performance). The results show that the directivity pattern of each instrument is different and has their own directivity characteristics. Measured directional and spectral characteristics of traditional Korean music sources were implemented into the computation of architectural acoustic measures. Significant differences in the acoustic measures at receiver positions were observed between the results in using the omni-directional source and the directional one. In order to investigate the acoustical characteristics of the instruments depending on the spatial variation four different shapes of halls were introduced including rectangular, fan. horse-shoe and geometrical shapes. Room acoustical parameters such as RT, SPL, C80, LF, STI were calculated at each type or hall. As the results, It was found that the rectangular hall has the most high clarity. lateral energy and STI values among low shapes of halls. It is thought that the suggested source data and design method can be used as a basic reference in the future acoustic design of performance halls for the Korean traditional music.

A Study on the Line of Action Shown in Characters' Poses of a Game 'Over Watch' (게임 '오버워치' 캐릭터의 Pose에 나타난 Line of Action 연구)

  • Lee, YuSeop;Chung, JeanHun
    • Journal of Digital Convergence
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    • v.15 no.12
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    • pp.489-494
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    • 2017
  • In spite of lots of differences in the production process of film animation, the animating method through computer is not much different between game animation and film animation. It is because the principles of film animation are also emphasized for the production of game animation. This study aims to consider the line of action showing the direction of movement and flow of energy among many considerations for the character pose work in case when producing game animation. Starting from the basic theory of drawing, the line of action plays a role of bible in the pose work including cell animation and 3D animation. After examining the theoretical background through preceding researches in order to understand the application of the line of action to the pose work of game characters, the poses of hero characters of a 3D online game 'Over Watch' were collected and then lines were directly drawn to analyze them. And as a result, the pose of characters with simple and clear 'Line of action' was good. This study aimed to consider the expression techniques of character pose in the production of game animation, which is expected to be used as an important reference for game animators at work.

Assessment of Diet Quality by Weight Status and Its Association with Obesity in Children and Adolescents (소아청소년 체중상태에 따른 식사의 질 평가 및 비만과의 연관성 분석)

  • Yang, See-Won;Lee, Hyang-Suk;Kim, JiEun;Kim, YoonMyung;Seo, Young-Gyun;Park, Kyung Hee;Jang, Han Byul;Lee, Hye-Ja;Park, Sang Ick;Lim, Hyunjung
    • Journal of the Korean Dietetic Association
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    • v.23 no.3
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    • pp.263-273
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    • 2017
  • Numerous studies have investigated quantifying dietary intake according to the weight status of children and adolescents. However, studies on differences in quality among diets remain scarce. This study compared diet quality by weight status and examined correlations between quality of diet and obesity in children and adolescents. Two hundred fourteen children and adolescents aged between 9 and 18 years participated in this study (Normal weight n=104, Obesity n=110). The data related to food intake were investigated by dietary records, Diet Quality Index-International (DQI-I), and Nutrition Quotient (NQ) and then compared with Dietary Reference Intakes for Korean (KDRIs). In DQI-I, moderation factor (control of unhealthy foods) score was 21.7 in the normal weight group and 19.5 in the obesity group. The normal weight group showed a higher score for moderation factor than the obesity group (P<0.001). Compared with KDRIs, vitamin $B_6$, folate, vitamin C, vitamin E, calcium, potassium, and zinc intakes were insufficient in both groups. Multiple logistic regression analysis revealed that DQI-I moderation was negatively associated with obesity (OR=0.77, 95% CI 0.69-0.87) after adjustment for age, gender, income, and total energy intake. Our results suggest that children and adolescents require nutritional education to understand the importance of vitamin and mineral consumption. Especially, education for children and adolescents with obesity needs to emphasize moderation of nutrient intake that can cause diseases with hyper-ingestion such as sodium and high calorie-low nutrition foods.