• 융합정보논문지
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• 제8권5호
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• pp.153-158
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• 2018

본 논문에서는 가시광 통신시스템에서 조명과 통신의 성능을 동시에 만족하기 위한 Dimming level control 기법을 연구하였다. 일반적으로 가장 많이 사용되는 OOK와 RZ-OOK변조 방식의 경우, 연속적인 Burst Zero Duration이 발생하면 조명 기능이 심각하게 저하된다. 이는 조명뿐만 아니라 시스템 전체의 성능을 열하시키는 원인이 된다. 본 연구를 통해, 기존 시스템의 Dimming level특성을 분석하고, Dimming level을 높이기 위한 기법으로 Illegal Pulse Insertion(IPI) 알고리즘을 제안하였다. 이를 통해, Dimming level을 효과적으로 제어하고 기존 변복조 시스템에서 나타나는 플리커(flicker) 현상과 Dimming level 감소를 해결하여 조명과 통신 양쪽 모두의 QoS를 향상 시킬 수 있다.

• 대한가정학회지
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• 제27권4호
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• pp.105-122
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• 1989

The purpose of this study is to provide the basic data to analyze the importance of family as the consumer socialization agents influencing consumer socialization and to enhance the adolescent children's level of consumer skill. The summary of research results is as follows: 1. There were significant differences in the mothers' level of consumer socialization according to the age, education level, consumer attitude, children's grade. 2. The factors showing significant relations to children's level of consumer skills were found to be children's sex, their grade, mother's age and their consumer attitude. The similar results were found for the various aspects of consumer skills. 3. Both the mother's level of consumer socialization with respect to themselves and with respect to children were found to be positivily correlated to children's level of consumer skills. 4. The result of analyzing the independent contribution of the factors in affecting the childern's level of consumer skills is that in order of increasing contribution the factors are the mother's level of consumer socialization with respect to children, children's grade, their sex, the mother's age. 5. The mother's level of consumer socialization with respect to themselves and with respect to children were found to be considerably influenced by demographics and socio-psychological variables. And it was confirmed that the mother's level of consumer socialization has causal relations to children's level of consumer skills.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.405-410
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• 2000

Multi-level (macro-level, meso-level, and micro-level) mechanism of prefinitely strained concrete materials os studied The multi-level analysis explains the additional quasibrittle concrete material ductility that comes from lateral confinement and their multi-level interaction mechanisms. The so-called "upgraded tube-squash test" is used to achieve 50% axial strain and over 70 degree of deviatoric strain of quasibrittle concrete materials under extremely high pressure without producing visible cracks. In the micro-level analysis, the variations of hydration rte, micropores, and hydrate phased are analyzed. In the meso-level analysis, mesocracks (the initial invisible cracks) at the interfaces between aggregates and cement paste matrices are studied. The high confining effect in the specimen on the meso-level cracks is also studied. In the macro-level analysis, the physical behavior of prefinitely strained concrete materials is studied. The co-relationships of the results from the three distinct levels of analyses based in various prestraining (0%, 15%, 35%, and 50%) are studied. For the extremely deformed or strained concrete problems, multi-level analysis will be used to explain the unclear and unstudied mechanism of concrete materials, The multi-level analysis can provide us with valuable insights that can explain the additional ductility and confining effect in concrete. concrete.

• 산업경영시스템학회지
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• 제23권60호
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• pp.11-22
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• 2000

The main objective of this research is to analyze an order point and an order quantity of a distribution center and each branch to attain a target service level in multi-level inventory distribution system. In case of product item, we use the item with low volume of average monthly demand. Under the continuous review method, the distribution center places a particular order quantity to an outside supplier whenever the level of inventory reaches an order point, and receives the order quantity after elapsing a certain lead time. Also, each branch places an order quantity to the distribution center whenever the level of inventory reaches an order point, and receives the quantity after elapsing a particular lead time. When an out of stock condition occurs, we assume that the item is backordered. For considering more realistic situations, we use generic type of probability distribution of lead times. In the variable lead time model, the actually achieved service level is estimated as the expected service level. Therefore, this study focuses on the analysis of deciding the optimal order point and order quantity to achieve a target service level at each depot as a expected service level, while the system-wide inventory level is minimized. In addition, we analyze the order level as a maximum level of inventory to suggest more efficient way to develop the low demand item model.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.837-840
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• 2009

최근, 박스 및 팔레트 단위가 아닌 개별 단위 물품에 바코드 대신 RFID를 부착하는 Item Level RFID 시장이 향후 국내외적으로 확대될 조짐이다. 이에 본 연구에서는 개별 단위 물품에 RFID를 적용하는 Item Level RFID 서비스 수요를 분석함으로써 RFID 산업의 활성화를 촉진하고, 발전시킬 수 있는 전략들을 도출해 보고자 한다. 본 연구는 다음과 같은 내용으로 구성되어 있다. 첫째, Item Level RFID 국내외 시장동향을 분석하였다. 둘째, RFID 수요 기업들을 대상으로 설문조사를 실시하고 Item Level RFID 유망 서비스 분야, 시장선도 예상분야, 보급시기 선도분야, 도입시 장애요인을 분석하였다. 마지막으로 실증분석 결과를 바탕으로 Item Level RFID를 활성화할 수 있는 전략들을 제시하였다.

• 기본간호학회지
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• 제14권1호
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• pp.120-127
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• 2007

Purpose: This study was done to identify the level of stress, hardiness, and professional burnout of intensive care unit (ICU) nurses and to provide basic data for the qualitative improvement of nursing work achievement in the workplace. Method: The data were obtained from 129 ICU nurses through a questionnaire. Results: Stress showed positive correlation with the level of professional burnout and there was negative correlation between hardiness and professional burnout. Nurses in the group with a high level of stress, and a high level of hardiness reported a low level of professional burnout compared to those in the group with a lower level of hardiness (t=-2.60, p= .012). Nurses in the group with a low level of hardiness and a low level of stress showed a lower level of professional burnout than those with a high level of stress (t=3.51, p= .001). Conclusion: The results show that the high level of stress when coupled with a low level of hardiness of ICU nurses results in a high level of professional burnout. For this reason, it is important for nursing administration to support nurses to reduce levels of stress and the resulting burnout in ICU nurses.

• 한국안전학회지
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• 제35권2호
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• pp.28-33
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• 2020

Recently, the overseas construction market has been actively promoted for about 10 years, and overseas dam construction has been continuously performed. For the economic and safe construction of the dam, it is important to prepare the main dam construction plan considering the design frequency of the diversion tunnel and the cofferdam. In this respect, the prediction of river level during the rainy season is significant. Since most of the overseas dam construction sites are located in areas with poor infrastructure, the most efficient and economic method to predict the water level in dam construction is to use the upstream water level. In this study, a linear regression model, which is one of the simplest statistical methods, was proposed and examined to predict the downstream level from the upstream level. The Pyeongchang River basin, which has the characteristics of the upper stream (mountain stream), was selected as the target site and the observed water level in Pyeongchang and Panwoon gaging station were used. A regression equation was developed using the water level data set from August 22th to 27th, 2017, and its applicability was tested using the water level data set from August 28th to September 1st, 2018. The dependent variable was selected as the "level difference between two stations," and the independent variable was selected as "the level of water level in Pyeongchang station two hours ago" and the "water level change rate in Pyeongchang station (m/hr)". In addition, the accuracy of the developed equation was checked by using the regression statistics of Root Mean Square Error (RMSE), Adjusted Coefficient of Determination (ACD), and Nach Sutcliffe efficiency Coefficient (NSEC). As a result, the statistical value of the linear regression model was very high, so the downstream water level prediction using the upstream water level was examined in a highly reliable way. In addition, the results of the application of the water level change rate (m/hr) to the regression equation show that although the increase of the statistical value is not large, it is effective to reduce the water level error in the rapid level rise section. Accordingly, this is a significant advantage in estimating the evacuation water level during main dam construction to secure safety in construction site.

• 대한수학교육학회지:학교수학
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• 제16권3호
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• pp.445-469
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• 2014

이 연구는 현직 중등 수학교사가 학생들이 교과서 수학 과제를 해결하는 데 요구되는 인지적 노력수준을 어떻게 이해하고, 그에 따라 과제들을 선별할 수 있는지를 살펴보는데 초점을 두고 있다. 또한 교사가 수학교과서의 Low Level 과제를 학생들의 수학적 사고력을 향상시키도록 High Level 과제로 변형할 수 있는지를 알아보고자 하였다. 수학 과제의 선별 및 변형에 관한 설문지를 제작하여 서울 및 경기 지역의 중 고등학교 수학 교사들에게 설문검사를 실시하였고 이를 분석하였다. 분석 결과는 다음과 같다. 첫째, 2007 개정 교육과정 목표 및 수업 목표 등을 성취하기 위해 수업에서 반드시 다루어야 할 과제로 High Level 과제를 선택한 교사의 비율은 59%였고, PNC과제를 High Level 과제로 보는 교사의 비율은 32%였다. 둘째, 교과서 Low Level 수학 과제를 높은 인지적 노력수준을 요구하는 과제로의 변형에 대하여, 아무런 변형도 하지 못한 교사의 비율은 56%였고 High Level 과제로 변형한 교사는 50명 중 4명뿐이었다. 이는 예비교사 뿐만아니라 현직교사의 경우도 Low Level 과제를 High Level 과제로 변형하는데 어려움을 느끼고 있음을 보여준다.

• Journal of Nutrition and Health
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• 제1권1호
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• pp.19-25
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• 1968

In order to study the effect of source and level of the commonly used dietary fats on growth and metabolism of rats fed on low protein diet (rice diet) the weaning white rats were fed on various different experimental diets (see tables 1 and 2) during 11 weeks. The observations were made as follows : 1. Growth: (see table 3 and figures 1-9) In all dietary fats, among the 3 levels, 5% fat level is the best. Especially, the perilla oil group was remarkably good. 10% and 20% fat levels impaired the growth, consequently the growth rates of both 10% and 20% fat level groups were worse than those of Basal group (no fat added). However, 10% and 20% fat levels did not impaired the growth of VII group (10% soy flour added) In 5% fat level, the growth was good in sequence of perilla oil, tallow, sesame oil, soy oil and lard. 2. Feed consumption: (see table 3) In 20% fat level, the feed consumption was lowered. Generally, the feed consumption rate was proportional to the growth rate. In feed efficiency, 5% fat level was the best. 3. Liver weight: (see table 4) In liver weight per 100 G body weight, 20% fat level was the largest. This may be due to the poor body growth and liver fat accumulation. 4. Liver nitrogen: (see table 4) Generally, lower fat level groups showed liver nitrogen. Liver nitrogen is low in the groups of 20% fat level. 5. Liver fat: (see table 4) Generally, higher fat level groups showed higher liver fat. 6. Serum cholesterol: (see table 5) Generally, higher fat level groups showed higher serum cholesterol. Lard, sesame oil, and tallow groups showed higher level and soy oil and perilla oil groups showed lower level. Especially, perilla oil group showed remarkably lower level and VII group (10% soy flour added) showed lower level than VI group (same fat but no soy flour added).

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.627-638
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• 2018

This article describes an integrated Level 1-Level 2 probabilistic risk assessment (PRA) methodology to evaluate the radiological risk during postulated accident scenarios initiated during the decommissioning phase of a typical Mark I containment boiling water reactor. The fuel damage scenarios include those initiated while the reactor is permanently shut down, defueled, and the spent fuel is located into the spent fuel storage pool. This article focuses on the integrated Level 1-Level 2 PRA aspects of the analysis, from the beginning of the accident to the radiological release into the environment. The integrated Level 1-Level 2 decommissioning PRA uses event trees and fault trees that assess the accident progression until and after fuel damage. Detailed deterministic severe accident analyses are performed to support the fault tree/event tree development and to provide source term information for the various pieces of the Level 1-Level 2 model. Source terms information is collected from accidents occurring in both the reactor pressure vessel and the spent fuel pool, including simultaneous accidents. The Level 1-Level 2 PRA model evaluates the temporal and physical changes in plant conditions including consideration of major uncertainties. The goal of this article is to provide a methodology framework to perform a decommissioning Probabilistic Risk Assessment (PRA), and an application to a real case study is provided to show the use of the methodology. Results will be derived from the integrated Level 1-Level 2 decommissioning PSA event tree in terms of fuel damage frequency, large release frequency, and large early release frequency, including uncertainties.