• 제목/요약/키워드: dual problems

검색결과 491건 처리시간 0.023초

Maskless 방식을 이용한 PCB생산시스템의 진동 해석 (Vibration Analysis of PCB Manufacturing System Using Maskless Exposure Method)

  • 장원혁;이재문;조명우;김종수;이철희
    • 한국소음진동공학회논문집
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    • 제19권12호
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    • pp.1322-1328
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    • 2009
  • This paper presents vibration analysis of maskless exposure module in printed circuit board(PCB) manufacturing system. In order to complete exposure process in PCB, masking type module has been widely used in electronics industries. However, masking process confronts some limitations of application due to higher production cost for masking as well as lower printing resolution. Therefore, maskless exposure module is started to be in the spotlight for flexible production system to meet the needs of fabrication in variable patterns at low cost. Since maskless exposure process adopts direct patterning to PCB, vibration problems become more critical compared to conventional masking type process. Moreover, movements of exposure engine as well as stage generate vibration sources in the system. Thus, it is imperative to analyze the vibration characteristics for the maskless exposure module to improve the quality and accuracy of PCB. In this study, vibration analysis using the finite element analysis is conducted to identify the critical structural parts deteriorating vibration performance. Also, Experimental investigations are conducted by single/dual encoder measurement process under the operating module speed. Measurement points of vibration are selected by three places, which are base of stage, exposure engine and top of stage, to check the effect of vibration from the exposure engine. Comparisons between analysis results and experimental measurement are conducted to confirm the accuracy of analysis results including the developed FE model. Finally, this studies show feasibility of optimal design using the developed FE analysis model.

Modeling and coupling characteristics for an airframe-propulsion-integrated hypersonic vehicle

  • Lv, Chengkun;Chang, Juntao;Dong, Yilei;Ma, Jicheng;Xu, Cheng
    • Advances in aircraft and spacecraft science
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    • 제7권6호
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    • pp.553-570
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    • 2020
  • To address the problems caused by the strong coupling of an airbreathing hypersonic vehicle's airframe and propulsion to the integrated control system design, an integrated airframe-propulsion model is established, and the coupling characteristics between the aircraft and engine are analyzed. First, the airframe-propulsion integration model is established based on the typical nonlinear longitudinal dynamical model of an air-breathing hypersonic vehicle and the one-dimensional dual-mode scramjet model. Thrust, moment, angle of attack, altitude, and velocity are used as transfer variables between the aircraft model and the engine model. The one-dimensional scramjet model can accurately reflect the working state of the engine and provide data to support the coupling analysis. Second, owing to the static instability of the aircraft model, the linear quadratic regulator (LQR) controller of the aircraft is designed to ensure attitude stability and height tracking. Finally, the coupling relationship between the aircraft and the engine is revealed through simulation examples. The interaction between vehicle attitude and engine working condition is analyzed, and the influence of vehicle attitude on engine safety is considered. When the engine is in a critical working state, the attitude change of the aircraft will not affect the engine safety without considering coupling, whereas when coupling is considered, the attitude change of the aircraft may cause the engine unstart, which demonstrates the significance of considering coupling characteristics.

맞벌이가정과 일반가정의 식생활현황에 관한 비교 연구 (A Study on the Status of the Employed and Housewives' Meal Management in Daejeon City)

  • 김미리
    • 한국식품영양과학회지
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    • 제13권1호
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    • pp.107-116
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    • 1984
  • In order to obtain an information for the improvement of wives' meal management especially in dual-income families, the survey was carried out through questionaires to 159 married women teachers(employed wives: EW) and 157 housewives(HW) in Daejeon city, from the Sep. 20 to 30, 1983. Most of the two groups' wives did not plan menu(74.7 %), and considered taste firstly when meal preparation and food buying. In EW, time was more considered than the other points for meal preparation and cookbook was more used than other sources of cooking methods, while in HW, cost, and, the mass media (p<0.01). Among 6 convenience foods, sausage, ham were used more frequently in EW and instant noo-dles and fried fish cake, in EW. Both the two groups' dietary pattern of three meals was similar, but much more of the EW(56.1 %) purchased foods for between meals rather than prepared at home in comparision with the HW. Almost all the HW prepared three meals themselves but the EW did not so. In the EW, husband and mother-in-law often assisted with meal-related activities, but in the HE, daughters (p<0.01) . HE spent more time on meal-related activities than do EW (Hw: 4.1 hrs/day, Ew·: 3.2 hrs/day) . The preparation time for supper was longest among three meals. As the problems of meal management, both the two groups' wives pointed 'too much time' (43.1 %), 'lack of nutrition knowledge '(42.8 %), but EW' husbands, 'no variety of cooking method'(42.8 %), while HW' husbands, 'lack of nutrition knowledge'(34.3 %).

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Active SLA 기반 서비스 수준 협약의 자동화 (Automation of Service Level Agreement based on Active SLA)

  • 김상락;강만모;배재학
    • 한국인터넷방송통신학회논문지
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    • 제13권4호
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    • pp.229-237
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    • 2013
  • 최근 SOA와 클라우드 컴퓨팅 기반의 IT 서비스에 대한 수요가 증가하면서 서비스 당사자들 간에 SLA(Service Level Agreement, 서비스 수준 협약)에 대한 관심이 증대되고 있다. 통상 SLA는 자연어로 작성된 종이 계약서이다. 상업용 SLA 관리 툴에서 사용하는 SLA는 절차적 언어를 사용하여 계약서 내용을 애플리케이션 안에 암시적으로 구현된다. 이는 SLA 자동화 작업을 어렵게 한다. 또한 계약시스템에 대한 유지관리를 어렵게 하고 새로운 계약 요구사항을 적용하기 위해서는 소스 코드에 대한 광범위한 수정 작업이 뒤따른다. SLA 유지관리 과정에서 발생하는 문제의 근본 원인은 동일한 SLA가 문서형과 실행형으로 이원화 되어 있다는 것이다. 본 논문에서는 이러한 현행 SLA 관리의 문제점을 개선하기 위해서 능동형 SLA(ASLA : Active Service Level Agreement)를 기반으로 하는 능동형 SLM(ASLM : Active Service Level Management) 시스템을 제안한다. 이 시스템에서는 이원화된 SLA 처리 및 관리 과정이 능동형 SLA(ASLA)의 도입으로 일원화될 수 있음을 보였다.

성별과 연령에 따른 골밀도와 체질량지수 변화에 대한 연구 (The Study on the Changes of Bone Mineral Density and Body Mass Index According to Sex and Age)

  • 김민철;육태한;송범룡
    • 한방재활의학과학회지
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    • 제19권4호
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    • pp.135-150
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    • 2009
  • Objectives : Osteoporosis is the most common metabolic disease of the bone, and one of the most important public health problems around the world. Obesity rate gradually increases as women grow older. The purpose of the study was to investigate the changes between bond mineral density(BMD) and body mass index(BMI) according to sex and age. Methods : We measured the bone mineral density(BMD) of lumber spine(L2-L4) and femoral neck in 10000 normal adult, using dual energy X-ray absorptiometry (DEXA; DPX-alpha). and also measured the body mass index(BMI) in 9810 normal adult. then we analysed the changes of BMD and BMI according to sex and age. Results : 1. As getting older, male's T-score of lumbar spine(L2-L4) was slowly decreased. On the other hand, female's T-score of lumbar spine was sharply dropped after 46 years old. 2. As getting older, male's T-score of femoral was slowly decreased. On the other hand, female's T-score of femoral was sharply dropped after 49 years old. 3. Irrespective of age, male's BMI keep up the extent within a definite period of numerical value. As getting older, female's BMI continued its upward trend. Conclusions : Much more attention should be needed for female patient suffering from osteoporosis and obesity than male.

저소득 모자가족 아동방임 개입 프로그램 개발 및 효과성 연구 (Intervention Program on the Child Neglect of Low-income Female-headed Families)

  • 박영희;신혜섭
    • 한국사회복지학
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    • 제44권
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    • pp.146-177
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    • 2001
  • One of the difficulties of female-headed families face is economic hardship. Low-income single mothers work long hours, become isolated and feel burdened for dual roles. And many of them don't have relatives to share parenting roles. As a result, children of low-income female-headed families are easy to be neglected and left to form a delinquency-prone group in neighborhood. Traditionally, it has been viewed that children in female-headed families have problems due to the loss of father role. However, study indicates that these children can adjust well if the relationship between mothers and children is consistent and adequate. An Intervention program for low-income female-headed elementary children was developed and delivered in two community social welfare centers. The purpose of the program is to raise self-esteem. Two goals were 1) management of daily living habits and 2) improvement of family relations. Social workers maintained contact with mothers to talk about children's behaviors and to prompt hugging and touching. In addition, workers helped children to form good relationships with peers and school teachers. Children were satisfied with the program. Their family relations were improved statistically significantly after the program(wilcoxon signed rant test z=-2.934 p<.05). However, their self esteem were not improved significantly (wilcoxon signed test z=-1.173 p>.05). Qualitative analysis of each children were also discussed. The implications of the study are the followings: Intervention programs need to be delivered separately for low-grade and high grade elementary children because they have different developmental needs. The program also need to include education on sex and marriage as well as aggression reduction. Society needs to provide more support to single mothers for their personal and parenting needs.

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중년 여성의 체질별 피로 - 한방병원 내원환자를 중심으로 - (The Degree of Fatigue Depending on Constitution in Middle-Aged Women)

  • 신은주;한선희
    • 한국간호교육학회지
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    • 제10권1호
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    • pp.84-93
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    • 2004
  • Purpose: This study was conducted to investigate the subjective degree of fatigue, the degree of fatigue depending on constitution, and the factors related to fatigue in middle-aged women. Method: Data were collected from 51 patients, registered at Oriental Medicine Hospital in J-city and K-city respectively. The instrument used in this study were the Multidimensional Assessment of Fatigue and the Questionnaire of Sasang Constitution Classification Ⅱ. Data analysis was done SPSS Result: The characteristics of constitution in middle-aged women could be divided into three: twenty six people of Soeumin, thirteen people of Taeumin, and twelve people of Soyangin. The degree of fatigue in middle-aged women: the average score 30.61 out of the total score 40. Subdivision of fatigue scores: common fatigue degree 7.71, distress due to fatigue 7.67, degree of daily activity fatigue 7.43, and fatigue frequency in the previous week 7.84. There were significant differences in the degree of fatigue depending on constitution in middle-aged women(p=.033). This study revealed weight, exercise, and drinking are important factors that can exert influence on the degree of fatigue. Also, there was a big difference in the degree of fatigue depending on constitution. Conclusion: In conclusion, fatigue is one of the difficult problems with middle-aged women. And this study revealed that change in the weight(especially loss of weight), physical exercise, and drinking are important factors that can exert influence on the degree of fatigue. Also, there was a big difference in the degree of fatigue depending on constitution. Therefore it is necessary to develop Korean nursing intervention to providing an appropriate environment where there is the harmony of the dual principles of the negative and positive, and patients can be taken care of properly.

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일학습병행제 자격직종 개발에 관한 연구 -기계분야 금형직종을 중심으로- (Study of the Development for Qualification of Occupational Category Combined Working and Learning -Oriented toward Mold & die in Machine Field-)

  • 강석주
    • 한국산학기술학회논문지
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    • 제15권10호
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    • pp.5925-5932
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    • 2014
  • 본 연구는 선진국의 이원화 제도에 대하여 탐색하고 자격제도에 대한 문헌연구를 통해 다양한 사회 구성원의 추체들이 신뢰하고 인정할 수 있는 한국형 일 학습병행제 자격직종을 개발하여 학벌이 아닌 능력중심사회로 진입을 위한 평가도구를 개발하는데 그 목적이 있다. 연구의 목적을 달성하기 위하여 유형별 자격제도의 관리운영 현황을 분석했으며, 주요 선진국(독일, 영국, 미국, 호주)에서 관리 운영되고 있는 다양한 유형별 관련법, 관련부서, 자격수여 주체, 검정기관, 응시요건, 검정방법, 검정위원회, 검정과목, 합격기준 자격검정 현황을 분석하였고, 직무분석을 통하여 기계(금형)분야의 직무 및 교육내용을 분석하였다. 또한 기계(금형)분야의 출제기준 및 채점 방법을 제시했고, 필기시험과 실기시험에 대한 출제 예시도 제시하였다. 국가차원의 일 학습 병행 자격제도에 관한 기본 틀을 마련하고 방향을 정립하는 초석을 마련하였다.

한국의 초고령사회를 대비한 최소주거면적 기준의 인체측정학적 방법 연구 - Karl H. E. Kroemer의 인체측정학적 데이터 적용 방법 - (A Study on the Anthropometrical Method of Minimum Residential Space Standard for the Super-Aged Society of Korea - by Anthropometrical Data Application Methods of Karl H. E. Kroemer -)

  • 이호성
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제23권1호
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    • pp.15-24
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    • 2017
  • Purpose: Korea is expected to enter an aged society in 2018 and then a super-aged society in early 2025. The country's aging is progressing faster than any other country in the world. However, the foundation of the elderly friendly industry is weak, and measures at the government level are urgently needed. Especially, housing problems of the elderly are one of the most urgent measures to be taken. Korea does not have the minimum residential area standard for the elderly, and the current general minimum residential area standard is based on the survey of the housing situation without scientific evidence. Therefore, both standards need to be revised as soon as possible based on scientific evidence. Methods: The minimum residential area standard has been calculated following Karl H. E. Kroemer's Min or Max design also being called as-single cut and dual cut theory- as the maximum population value and minimum population value theory of Ernest J. McCormick. Therefore there is a need for a formula made using a few key factors, such as corresponding dimension, practical dimension, clearance, spare dimension, integrated dimension. These elements can be defined and used as formulas to calculate minimum residential area standards. Results: Assuming the results of the spatial variability in this study showed that it is possible to raise the standard of living in a terms of sustainable minimum size for the young, old and all residents. Implications: The government should set a minimum residential area standard with scientific grounds and set up a policy improving the life of people who live in an needy residential environment.

중앙버스전용차로 버스전용신호 도입시 신호 최적화에 관한 연구 (Development of Determining Technique of Optimum Signal Time of Intersections On Median Exclusive Bus Lane using Bus-only Signal)

  • 김보겸;김승일;김영찬;김진태
    • 대한교통학회지
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    • 제24권5호
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    • pp.123-133
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    • 2006
  • 서울시를 포함한 수도권 각 도시는 중앙버스전용차로의 적극적인 도입으로 버스속도 및 정시성 향상을 통해 대중교통우선 처리 전략을 적극 추진 중에 있다. 그러나 이로 인해 중앙부 $1{\sim}2$개 차로를 버스전용차로가 차지함으로써 기존 신호운영체계에 큰 변화를 가져오게 되었다 좌회전 차량과 중앙버스전용차로를 이용해 직진하는 버스간에 새로운 상충이 발생하게 되어 동시신호 기법 등 교차로 신호운영대안이 줄어들게 된 것이다 이 해결방안으로서 버스전용신호를 도입하여 중첩현시 및 동시신호 등 Dual-Ring방식의 다양한 신호 운영을 가능케 하는 방안이 모색되고 있다. 본 연구에서는 이러한 버스전용신호 도입 시 교차로 정체를 최소화할 수 있는 신호설계방법을 제시하였고, 중앙버스전용차로가 운영 중인 양재역사거리에 동 기법을 이용한 최적신호 설계를 적용, 시뮬레이션을 통해 그 효과를 검증하였다.