• Title/Summary/Keyword: case - control study

Search Result 6,341, Processing Time 0.038 seconds

An Analysis of the Factors Affecting Anemia in the Female Industrial Workers -Case-Control Study- (산업장 여성 근로자의 빈혈에 영향을 미치는 요인 분석 -환자-대조군 연구-)

  • Park, Myeong-Ho;Kim, Yong-Joon
    • Journal of Preventive Medicine and Public Health
    • /
    • v.22 no.2 s.26
    • /
    • pp.181-188
    • /
    • 1989
  • In this study an attempt was made to determine the factors affecting anemia in female industrial workers. The population was identified through the records of screening examinations given by Kosin Medical Center to the industrial workers in Sasang Industrial Complex during the period from March 1987 to October 1988. One hundred twenty eight cases were selected from the records screening examination of 155 anemic patients. A case-control study was carried out using matched 128 anemic cases and 128 non-anemic workers who were selected by simple random sampling. Age was matched, and their occupational history, general characteristics, physical characteristics and health status were analyzed. The results were; 1. In the anemic group, educational level was lower, and the frequencies of irregular menstruation and poor appetite were higher than in the control group but these differences were statistically not significant. 2. The percentage of workers working with organic solvents, working hours and years of service (total years exposed to organic solvents) were significantly higher in the anemic group than those in the control group. 3. A career exposed to organic solvents was more influential factor affecting anemia in the female industrial workers rather than menstruation amount of other factors, and it was statistically significant.

  • PDF

Vibration control of high-rise buildings for wind: a robust passive and active tuned mass damper

  • Aly, Aly Mousaad
    • Smart Structures and Systems
    • /
    • v.13 no.3
    • /
    • pp.473-500
    • /
    • 2014
  • Tuned mass dampers (TMDs) have been installed in many high-rise buildings, to improve their resiliency under dynamic loads. However, high-rise buildings may experience natural frequency changes under ambient temperature fluctuations, extreme wind loads and relative humidity variations. This makes the design of a TMD challenging and may lead to a detuned scenario, which can reduce significantly the performance. To alleviate this problem, the current paper presents a proposed approach for the design of a robust and efficient TMD. The approach accounts for the uncertain natural frequency, the optimization objective and the input excitation. The study shows that robust design parameters can be different from the optimal parameters. Nevertheless, predetermined optimal parameters are useful to attain design robustness. A case study of a high-rise building is executed. The TMD designed with the proposed approach showed its robustness and effectiveness in reducing the responses of high-rise buildings under multidirectional wind. The case study represents an engineered design that is instructive. The results show that shear buildings may be controlled with less effort than cantilever buildings. Structural control performance in high-rise buildings may depend on the shape of the building, hence the flow patterns, as well as the wind direction angle. To further increase the performance of the robust TMD in one lateral direction, active control using LQG and fuzzy logic controllers was carried out. The performance of the controllers is remarkable in enhancing the response reduction. In addition, the fuzzy logic controller may be more robust than the LQG controller.

A case study on the building of integrated CCTV control center at Busan metropolitan city (부산광역시 CCTV통합관제센터구축 사례연구)

  • Kwon, Chang-Hwan;Seo, Chang-Gab
    • Journal of Digital Convergence
    • /
    • v.9 no.3
    • /
    • pp.191-202
    • /
    • 2011
  • Public agencies and local governments have been installing CCTV cameras for the prevention of crime, traffic jam, and unauthorized waste. Additionally, national government agencies and schools, a special corporation by special law, local construction and industrial company installed CCTV cameras of their own and are operating them. Various types of CCTV systems disclosed technical heterogeneity. In February, 2011, Ministry of Public Administration and Security presented guidelines for building an integrated control center. This study examines the case of Busan by using the administrative guidelines. Busan integrated CCTV control center among themselves, police agency and fire department. This study looks into the potential problems with the integration process of CCTV cameras and proposes a solution to them.

Epidemiological and Clinical Characteristics of Confirmed Cases of Severe Fever With Thrombocytopenia Syndrome in Jeju Province, Korea, 2014-2018

  • Kim, Jinhee;Bae, Jong-Myon
    • Journal of Preventive Medicine and Public Health
    • /
    • v.52 no.3
    • /
    • pp.195-199
    • /
    • 2019
  • Objectives: Jeju Province is well known as the region showing the highest incidence of severe fever with thrombocytopenia syndrome (SFTS) in South Korea. The aim of this study was to evaluate the epidemiological and clinical characteristics of SFTS patients in Jeju Province. Methods: The primary data for this study were obtained from the Integrated Diseases and Health Control System of the Korea Centers for Disease Control and Prevention (KCDCIS). The selection criteria were confirmed cases of SFTS with a residence listed in Jeju Province at the time of diagnosis, reported to the KCDCIS between July 16, 2014 and November 30, 2018. Results: Of 55 confirmed cases of SFTS, the case fatality rate was 10.9% (95% confidence interval [CI], 4.1 to 22.2). The most common presenting symptoms at diagnosis of severe fever, myalgia, and diarrhea had incidences of 83.6% (95% Cl, 71.2 to 92.2), 45.5% (95% Cl, 32.0 to 59.5), and 40.0% (95% CI, 27.0 to 54.1), respectively. Conclusions: Compared to SFTS patients nationwide in 2013-2015, the subjects of this study exhibited a lower case fatality rate and had a lower incidence of severe fever, myalgia, and confusion.

Evaluation of Economic Damage Caused by Drought in Central Region Vietnam: A Case Study of Phu Yen Province

  • Truong, Dinh Duc;Tri, Doan Quang
    • Economic and Environmental Geology
    • /
    • v.54 no.6
    • /
    • pp.649-657
    • /
    • 2021
  • This paper aims to study the impact of natural disasters on per capita income in Vietnam both the short and long-term, specifically impact loss of income caused by the extreme drought 2013 for agriculture, forestry and fishery in Phu Yen Province, Central Vietnam. The study valued economic damage by applying the synthetic control method (SCM), which is a statistical method to evaluate the effect of an intervention (e.g. natural disasters) in different case studies. It estimates what would have happened to the treatment group if it had not received the treatment by constructing a weighted combination of control units (e.g. control provinces). The results showed that the 2013 drought caused a decrease in income per capita, mainly in the agriculture, forestry, and fishery sector in Phu Yen. The reduced income was estimated to be VND 160,000 (1 USD = 23,500 VND (2021)) for one person per month, accounting for 11% of total income per capita and continued to affect the income 6 years later. Therefore, authorities need to invest in preventive solutions such as early and accurate warnings to help people to be more proactive in disaster prevention.

A Study on Improving Lecture Satisfaction using Taguchi Method (다구찌 기법을 적용한 강의만족도 향상 사례 연구)

  • Ree, Sangbok
    • Journal of Korean Society for Quality Management
    • /
    • v.42 no.1
    • /
    • pp.63-70
    • /
    • 2014
  • Purpose: This article introduces a case study of using Taguchi Method to improve lecture satisfaction. Developed by Taguchi Genichi, this method has its strength in finding the control factor that is robust against noise factor. Finding the condition for such control factor has an effect of reducing the dispersion of the Lecture satisfaction. Methods: There are various factors in university classrooms. The factors which influenced the Lecture Satisfaction are analyzed by control factors and noise factors, control factors which is controllable are lecture completeness and thoroughly test the degree of supervision and noise factors which is not controllable is degree of physical and psychological Lecturer tired, then the experiment is conducted as guided by Taguchi's experimental design, one semester are experimented by eight professor with 2 classes, after discussion of the results the optimal lecture condition is suggested. Results: To improve Lecture Satisfaction under noise factor of physical and psychological Lecturer tired, optimal condition are that lecture completeness have scenario note during lecture and thoroughly test the degree of supervision have two proctors during test. Conclusion: In this paper, we have succession case by applying Taguchi methods in Lecture Satisfaction. We can apply to improve service by applying the Taguchi methods. In the future we hope to have many succession cases.

A Study on the Affected of DC-Link Voltage Balance Control of the Vienna Rectifier Linked With the Input Series Output Parallel LLC Converter (직렬 입력 병렬 출력 연결된 LLC 컨버터를 갖는 비엔나 정류기의 DC 링크 전압 평형 제어에 관한 연구)

  • Baek, Seung-Woo;Kim, Hag-Wone;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.26 no.3
    • /
    • pp.205-213
    • /
    • 2021
  • Due to the advantage of reducing the voltage applied to the switch semiconductor, the input series and output parallel combination is widely used in systems with high input voltage and large output current. On the other hand, the LLC converter is widely used as a high-efficiency power converter, and when connected by ISOP combination, there is a possibility that input voltage imbalance may occur due to a mismatch of passive devices. To avoid damaging the switching device, this study analyzed the DC-link voltage imbalance of a high-capacity supply using an ISOP LLC converter. In addition, the case where DC-link unbalance control was applied and the case not applied was analyzed respectively. Based on this analysis, an initial start-up algorithm was proposed to prevent input power semiconductor device damage due to DC-link over-voltage. The effectiveness of the proposed algorithm has been verified through simulations and experiments.

A Comparative Study of knowledge, attitude, and practice by Before-after trafffic safety education : focusing on the 4th grade student in elementary school (교통안전교육 전 . 후의 지식, 태도 및 실천에 관한 비교 연구 -초등학교 4학년 학생을 대상으로-)

  • 임승지;이명선
    • Korean Journal of Health Education and Promotion
    • /
    • v.16 no.1
    • /
    • pp.31-43
    • /
    • 1999
  • Increase of automobiles become today's environmental problem decreasing space for our children's playground. The traffic situation around us shows automobiles over filled the public roads and started to intrude even on the side walks. Children's traffic safety education for the awareness of the danger from traffic mishaps, and for the behavior to cope with preventives measure by continual learning programs in systematized method is very important need in current health education. For this research, the subject was represented by 243 students from 4th grade in D Elementary School located at Daechi-dong, Seoul. During total of 5 weeks (September 4, 1997 to September 30, 1997), lessons were taught to the subject. Lessons consist of traffic safety education and customized education program that were designed and developed specificially for the subject level. In this research, Case group of 3 classes and control group of 3classes were predetermined before subject's degree of knowledge, attitude, and practice was analized. The difference before and after the training of this education was observed to verify the effectively and to find the influential factors of this education program. On September 2-3, survey study was performed after the training. the results of this study were as follows: 1. The knowledge analysis from the comparison between before and after of the training shows case group and control group scored(8.36, 8.86) before the traning, but scored(10.36, 8.52) after the traning. the difference from the result of the case group is statistically significant(p〈0.001). 2. The attitude analysis from the comparison between before and after of the training shows case group and control group scored(48.23, 49.87) before the training, but scored (51.05, 48.45) after the traning. the difference from the result of the case group is statistically significant(p〈0.001) 3. The practice analysis from the comparison between before and after of the training shows case group and control group scored (27.42, 28.08) before the training, but scored(30.49, 28.25) after the training. The differece from the result of the case group is statistically significant (p〈0.001). 4. The correlation analysis of traffic safety education's influence on traffic safety knowledge, attitude, and practice before training shows the relationship between attitude and practice was satistically significant(p〈0.05). The result after the training shows the relationship between knowledge and attitude, attitude and practice, and knowledge and practice was all statistically significant(p〈0.001).

  • PDF

A Design of Control Chart for Fraction Nonconforming Using Fuzzy Data (퍼지 데이터를 이용한 불량률(p) 관리도의 설계)

  • 김계완;서현수;윤덕균
    • Journal of Korean Society for Quality Management
    • /
    • v.32 no.2
    • /
    • pp.191-200
    • /
    • 2004
  • Using the p chart is not adequate in case that there are lots of data and it is difficult to divide into products conforming or nonconforming because of obscurity of binary classification. So we need to design a new control chart which represents obscure situation efficiently. This study deals with the method to performing arithmetic operation representing fuzzy data into fuzzy set by applying fuzzy set theory and designs a new control chart taking account of a concept of classification on the term set and membership function associated with term set.

Semiclosed Control of 2 Inertia System By Disturbance Observer (외란관측기를 이용한 2관성계의 반폐회로 제어)

  • 이건복;최순필
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2000.10a
    • /
    • pp.140-143
    • /
    • 2000
  • Motion control system using motor generally consists of 2 inertio system, motor inertio and load inertio linked with flexible coupling. In the case of direct drive motor control, the effect of coupling inertio decrease the precision performance. The study is about semiclosed control scheme of the system and experimental setup. To compensate the effect of coupling inertio, semiclosed control system by disturbance observer is employed. The simulation result is shown.

  • PDF