• 한국지능시스템학회논문지
• /
• 제17권3호
• /
• pp.355-367
• /
• 2007

본 논문에서는 설계변수와 제어기 이득의 자기 동조를 사용한 PI+D 제어기 설계법을 제안한다. 사용된 퍼지 PI+D 제어기는 일반적인 연속 시간 선형 PI+D 제어기를 근사화하여 사용하였고, 퍼지화는 퍼지싱글톤으로, 비퍼지화는 간략화된 무게중심법을 사용하였다. 퍼지추론 결과는 분리된 퍼지 변수로서 다른 작용 성분으로 계산되고, 그 결과는 설계변수에 해당하는 함수의 형태로 결정되어 제어이득을 결정한다. 따라서 제안된 방법은 빠른 동조 성능을 가지며, 퍼지 입력변수의 증가에도 쉽게 적용될 수 있고, 재생 오차를 줄이는 이점을 가진다. 이 제어기는 설계변수와 제어기 이득의 사용으로 보다 높은 효율성과 개선점을 가지고 있다.

• 한국산학기술학회논문지
• /
• 제18권1호
• /
• pp.572-578
• /
• 2017

사용자가 원격으로 가상환경에 접속하여 가상물체를 조작할 때 현실감을 증강시키기 위해서 햅틱 시스템이 사용된다. 그러나 원격 시스템 환경에는 통신시간지연이 발생하며, 발생된 통신시간지연은 햅틱 시스템을 불안정하게 만들 수 있다. 본 논문에서는 종래의 샘플-홀드 방식인 영차홀드 (ZOH; Zero-Order-Hold)가 아닌 일차홀드 (FOH; First-Order-Hold)를 포함하는 햅틱 시스템에서 시뮬레이션을 통해 통신시간지연과 햅틱 장치의 물성치 변화에 따른 가상 스프링상수의 안정성 영역을 분석하고 이를 통해 안정적인 햅틱 시스템을 구현하고자 한다. 통신시간지연이 없으면 일차홀드 (FOH) 방식이 영차홀드(ZOH) 방식보다 가상 스프링상수의 안정성 영역을 증가시킬 수 있었다. 그러나 통신시간지연이 증가하면, 샘플-홀드 방식보다 통신시간지연이 시스템 안정성에 더 큰 영향을 끼치므로, 샘플-홀드 방식에 따른 가상 스프링상수의 안정성 영역 크기에는 차이가 없어진다. 또한 통신시간지연과 일차홀드 방식이 포함되면 가상 스프링상수의 안정성 영역은 통신시간지연 크기에 반비례하고, 햅틱 장치의 댐핑상수 ($B_d$)에 정비례하여 증가하지만, 햅틱 장치의 질량 ($M_d$)에는 영향받지 않음을 알 수 있었다.

• 한국생활과학회지
• /
• 제17권3호
• /
• pp.413-423
• /
• 2008

The purpose of this study was to consider the evaluations of curriculum and young children by kindergarten teachers. The investigation subjects for questionnaire were 637 (the directors, vice-directors, the head teachers, and teachers) who were selected by proportional stratified sampling method for population and the subjects for interview were 11 teachers out of previous subjects who have worked at Jeolla-Do. The questionnaire was based on preceding studies and the propriety of contents was validated. The followings are results of this study. First, according to the purpose of curriculum, more than half of kindergarten teachers answered that they do perform evaluation to validate the young children's developmental process and there were statistically no significant differences by variables of kindergarten teachers. This study was to see whether they perform the evaluation results of curriculum or not, they relatively perform and there were statistically differences by kindergarten teacher's working location, establishment type, level of education and age. This study was to see whether they reflect the evaluation results of curriculum, and it was revealed as they relatively reflect. Also, there were statistically significant differences by kindergarten teacher's working location. And, kindergarten teachers requested the appropriate evaluation curriculum that also requires the adequate education for teachers and organized supporting system as a implication plan. Second, as of material types for children's portfolio evaluation, teachers collect activity products at most, then activity picture, observation, standardized test, teacher's journal, recording or tape-recording, post-interview and data that were collected at home. And, kindergarten teachers requested the appropriate evaluation method and the supply of human resources as a implication plan for young children's evaluation.

• 전자공학회논문지
• /
• 제52권2호
• /
• pp.162-170
• /
• 2015

컴뮤트 타임 임베딩을 구현하려면 그래프 라플라시안 행렬의 고유값과 고유벡터를 구하여야 하는데, $o(n^3)$의 계산량이 요구되어 대용량 데이터에는 적용하기 어려운 문제가 있다. 이를 줄이기 위하여 표본화 과정을 통하여 크기가 줄어든 그래프 라플라시안 행렬에서 구한 다음, 원래의 고유값과 고유벡터를 근사화시키는 Nystr${\ddot{o}}$m 기법을 주로 채택한다. 이 과정에서 많은 오차가 발생하는데, 이를 개선하기 위하여 본 논문에서는 그래프 라플라시안 대신에 가중치 행렬을 표본화하고 이로부터 구한 고유값과 고유벡터를 그래프 라플라시안의 고유값과 고유벡터로 변환하는 기법을 이용하여 대용량 데이터로 구성된 스펙트럴 그래프를 근사적으로 컴뮤트 타임 임베딩하는 기법을 제안한다. 하지만, 이 방식도 스펙트럼 분해를 계산하여야 하므로 데이터의 크기가 증가하면 적용하기 어려운 문제가 발생한다. 이의 대안으로, 스펙트럼 분해를 계산하지 않고도 데이터 집합의 크기에 영향을 받지 않으면서 컴뮤트 타임을 근사적으로 계산하는 방식을 구현하고 이들의 특성을 실험적으로 분석한다.

• 한국조사연구학회지:조사연구
• /
• 제9권3호
• /
• pp.1-21
• /
• 2008

우리나라의 주택시장은 대부분 매매시장과 전세시장이 주를 이루어 왔다. 그러나 1997년 외환위기를 거치면서 우리나라 주택시장을 둘러싼 제반 여건이 급격하게 변하면서 주택 임대차시장에서도 뚜렷한 변화가 일어나게 된다. 과거 전세 위주의 임대차계약에서 보증부월세나 완전월세의 비중이 급격하게 늘어난 것이다. 그런데 매매가격이나 전세가격 관련 통계가 쏟아져 나오는 것과는 달리 월세가격에 대해서는 신뢰할 만한 통계가 거의 없다. 더욱이 우리나라 주택시장에서의 월세는 완전월 세보다 다양한 형태의 보증부월세가 주를 이루고 있기 때문에 월세 개념을 어떻게 규정해야 할지도 불명확한 상태이다. 본 연구는 주택 매매가격이나 전세가격동향지수에 상응하는 월세가격동향지수 통계를 개발하기 위한 기초 연구이다. 우리나라 월세시장 현황을 파악하여 현실적으로 바람직한 월세의 개념을 정립하고 월세조사를 위한 합리적인 조사방법을 마련하며, 2005년 주택총조사 결과에 기초한 표본의 설계 및 월세가격지수 산출 방안을 제시하는 것이 본 연구의 목적이다.

• 보건행정학회지
• /
• 제19권3호
• /
• pp.109-124
• /
• 2009

Background: This study aimed to examine whether cases of punishing false claimants threat general physicians to check their medical cost claims with care to avoid being suspected, and identify empirically general deterrence effects of the on-site investigation system in the Korean National Health Insurance. Methods: 800 clinics were selected among a total of 15,443 clinics that had no experience of on-site investigation until June 2007 using a stratified proportional systematic sampling method. We conducted logistic multiple regression to examine the association between factors related to provider's perception of on-site investigation and high level of perceived deterrence referring to fear of punishment after adjusting provider's service experiences and general characteristics. Results: The probability of high perceived deterrence was higher 1.7 times (CI: 1.13-2.56), 2.73 times (CI: 1.68-4.45) each among clinics exchanging the information once or more per year or once or more for 2-3 months than among clinics no exchanging the information about on-site investigation. Also, the probability of high perceived deterrence was higher 2.27 times (CI: 1.28-4.45) among clinics that knows more than 3 health care institutions having experienced an on-site investigation than among clinics knowing no case. Conclusion: A clinic knowing more punishment cases by onsite investigation and exchanging more frequently information about on-site investigation is likely to present high perceived deterrence. This result will provide important information to enlarge preventive effects of on-site investigation on fraud and abuse claims.

• 대한간호학회지
• /
• 제39권5호
• /
• pp.741-750
• /
• 2009

Purpose: The purpose of this study was to identify the prevalence of cognitive impairment, behavioral problems, and the state of mental health for elderly Korean people who have been institutionalized. Methods: A cross-sectional, nationwide survey was performed using an anonymous questionnaire. The participants in this study were 2,521 institutionalized elderly Korean people. A proportional stratified random sampling method was employed. Results: 1) Elders admitted to subacute hospitals and long term care (LTC) facilities showed a higher level of cognitive impairment compared to elders admitted to acute care hospitals. 2) Elders confined in LTC facilities showed a higher level of behavioral problems compared to elders in acute or subacute hospitals. 3) Elders admitted to subacute hospitals and LTC facilities showed more serious mental health problems, such as depression or suicidal ideation, compared to elders in acute care hospitals. Conclusion: The results of this study indicate that the severity of cognitive-behavioral or mental health problems do not match well with type of care setting. Therefore, health personnel working with elderly people should be provided guidance on detection and management of cognitive-behavioral and mental health problems. The necessity of a decision support system for eligibility and placement in long-term care is also discussed.

• 지역사회간호학회지
• /
• 제25권1호
• /
• pp.33-43
• /
• 2014

Purpose: To evaluate the influence of experiences of witnessing tobacco advertising and preferences of tobacco companies' social responsibility (CSR) on current and future smoking intentions in adolescents. Methods: Data were collected from 700 adolescents living in Korea representing 7 metropolitan cities and 8 provinces in the method of proportional random sampling. The Gallup's data collection system was adopted using 1:1 face to face interviews. The witness of tobacco advertising was determined by 'yes', or 'no' responses to three survey items and to four survey items for preferences of tobacco CSR. For statistical analysis, ${\chi}^2$ test, Fisher's exact test and logistic regression were used. Results: 98.4% of the adolescents had experiences of witnessing tobacco advertising. POP (OR=103.44, 95% CI: 8.22~1301.45) and magazine advertisement (OR=6.07, 95% CI: 1.34~22.58) had a significant effect on their current smoking. Also, POP (${\beta}$=.24, p<.001) and movie advertisement (${\beta}$=.42, p<.001) had a significant effect on their future smoking intentions. As for the preferences of tobacco CSR, cultural-art support activities (${\beta}$=.15, p=.025) and environmental purifying campaigns (${\beta}$=-.15, p=.034) had a significant effect on their future smoking intentions. Conclusion: Witness of tobacco advertising and positive responses to tobacco CSR are associated with current and future smoking intentions in adolescents.

• 지역사회간호학회지
• /
• 제25권1호
• /
• pp.1-11
• /
• 2014

Purpose: The purpose of this study is to obtain information of use of complementary and alternative medicines (CAMs) and any reported adverse effects of them on vulnerable elders in a community. Methods: 1,837 elderly subjects aged 65 or higher with health problems were selected from those who were enrolled in a public health care center and received visiting health management services. A proportional stratified sampling method was used. Data collection was completed by face to face interviews using a structured questionnaire. The descriptive statistics and ${\chi}^2$-test were used to analyze the data. Results: The prevalence of CAM use last year was 57.5%, and 10.4% of the subjects reported adverse effects of the therapies. The mean score of the subjects' attitudes towards CAM was $4.1{\pm}3.44$ (range 1~10). The major sources of advice and exposure to CAM therapies were most likely to be from family and friends (72.5%). The primary reason for choosing CAM was to manage symptoms and relieve pain (86.6%). Conclusion: These findings suggest the need to develop nursing strategies for reducing and preventing adverse effects of CAM use by promoting awareness of using safe and appropriate CAM therapies.

• 보건교육건강증진학회지
• /
• 제18권2호
• /
• pp.129-140
• /
• 2001

Harmful environment around school area have been increased with socio-economic development in Korea. Those entertainment facilities have caused a negative effect on the learning environment in many schools. As a result of increased entertainment harmful facilities in school area, the numbers of deviant behaviors such as drinking, smoking, substance abuse and sexual activity among junior high school students have been significantly increased. Given this situation, the aim of this study was to describe the distribution of the facilities; to access applied(experience) of the facilities according to students demographic variables; and to identify the relationship between use of the facilities and students risk health behaviors such as smoking, drinking, substance abuse and sexual activity. The field theory was used to study the relationship between the use of the facilities and risk health behaviors among students. A self-administered questionnaire survey was conducted in Korea. 2,114 junior and senior high school students(middle and high school students) were recruited by the method of proportional stratified random sampling from June to July 2000. Results indicated that: 1) The rates of using game centers, PC rooms, Song rooms and comic rooms were 78.3%, 75.6%, 71.6%, and 34.3% respectively. 2) High school students visited the entertainment facilities significantly more than middle school students(p〈0.001). 3) The rates of using facilities near schools were significantly associated with parents job(p〈0.05). 4) The rates of drinking, smoking, drug abuse, and sexual activity were 21.6%, 11.9%, 4.3% and 1.6% respectively. 5) Risk health behaviors such as smoking(p〈0.001) and drinking(p〈0.001), amount of smoking and drinking(p〈0.001) and sexual activity(p〈0.05) were associated with the experience of using the facilities. Those who had drinking experience were more likely to go the facilities than those without drinking experience. Also, those who were smoker had higher probability of going using the facilities than non-smokers.