• Title/Summary/Keyword: case-control

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The Association between Childhood Asthma and Residential Environment through Case-Control Study (어린이 천식과 주거환경적 위험요인에 대한 환자-대조군 연구)

  • Hwang, Gyu-Seok;Yoon, Chung-Sik;Choi, Jae-Wook
    • Journal of Environmental Health Sciences
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    • v.38 no.3
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    • pp.223-232
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    • 2012
  • Objective: We performed this study to determine the association between childhood asthma and residential environment risk factors including VOCs and formaldehyde exposure. Methods: We selected an asthma group (30) and a control gorup (30) through physicain diagnosis and assessed the VOCs and formaldehyde levels of exposure of elementary school children in Seoul. Results: In the results, there were no significant differences in socioeconomic factors between case and control groups. However, there were significant differences in family asthma history, amount of sunlight, level of humidity and number of household residents (p < 0.05). The level of VOC (toluene, ethylbenzene, stylene, m,p-xylene) exposure level of the case group was significantly higher than that of the control group (p < 0.05) and the result of logistic regression showed that asthma family history, amount of humidity and number of household residents were significant predictors of childhood asthma (p < 0.05). Conclusion: Some residential environments such as lower amounts of sunlight, greater amounts of humidity and smaller numbers of household residents and VOC exposure were determinded as risk factors for childhood asthma.

Food Intake and Breast Cncer Risk: A Case-Control Study (식품섭취에 따른 유방암의 발생 위험 : 환자- 대조군 연구)

  • 도민희;이상선;정파종;이민혁
    • Journal of Nutrition and Health
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    • v.34 no.2
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    • pp.165-175
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    • 2001
  • We performed case-control study to evaluate relationship between food intake and risk of breast cancer. We interviewed breast cancer cases(n=108) who were newly histologically identified and selected from Hanyang and Soonchunhyang University Hospital in Seoul. We used hospital-based control subjects(n=121), who were selected from the patients in the department of plastic surgery, general surgery and opthalmology of the same hospital by frequency matching. Matching variables were age($\pm$4 age) and menopausal status. We collected information on general characteristics of subjects, history of disease, family history of breast cancer, vitamin supplementation, alcohol intake, and food intake through individual interview. Dietary information was ascertained via a food frequency questionnaire method(total item=98). All analyses was conducted according to menopausal status. Especially, pepper and grape intake in premenopausal women, showed protective effect in breast cancer. Otherwise consumption of meat, pork, and fish was not associated with breast cancer risk in this study. At milk and dairy products, milk intake was associated with lower risk of breast cancer in postmenopausal women and overall intake of soy products was associated with breast cancer risk, but not significant. These findings suggested that consumption of some fruit and vegetable intake was a protective factor on breast cancer and further study with more number of subjects should be need to evaluate the breast cancer risk. (Korean J Nutrition 34(2): 165~175, 2001)

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A Case -Control Study on Dietary and Other Factors Related to Stomach Cancer Incidence (위암 발생의 식이 및 관련요인에 대한 환자군-대조군 연구)

  • 염필영
    • Journal of Nutrition and Health
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    • v.31 no.1
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    • pp.62-71
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    • 1998
  • As stomach cancer is very prevalent in Koreans, various factors, especially dietary factors, related to stomach cancer incidence were examined in a case-control study. The study population consisted of 105 individual s diagnosed for stomach cancer in two general hospitals and 124 control subjects, matched for age and sex, in Seoul. Data for general characteristics, family history, smoking and alcohol consumption, personality , dietary habits and food preference were obtained by self-administered questionnaire and personal interview. Heredity was found to be one of the most important factors causing stomach cancer. In addition, genetic inheritance tended to differ between the sexes. The male patients showed significantly higher incidence of their father's relatives than mother's relatives but the female patients showed higher incidence of their mother's relatives that father's relatives. Smoking was significantly related to stomach cancer. It was also found that the cases drank alcohol more frequently and in much greater quantity than the controls. Personality was related to the incidence of stomach cancer. The cases tended to be more sensitive , impatient, and anxious to do things quickly. With regards to dietary habits, the male cases had meals significantly more irregularly than the male controls. The relative risk of preferencefor salty food and ramen showed to be significantly very high. The male cases consumed carbonated beverages and instant foods, low intake of green yellow vegetables, smoking of cigarettes and drinking of alcohol may contribute to the risk of stomach cancer.

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THE STUDY ON THE SEPARATED FLOW OF A HUMP USING RANSMODELING (RANS 모델링을 이용한 Hump 형상의 박리 유동에 대한 연구)

  • Lee, J.;Bae, J.H.;Jung, K.J.
    • Journal of computational fluids engineering
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    • v.22 no.1
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    • pp.8-14
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    • 2017
  • In this paper, separated flow characteristics is studied using the RANS(Reynold-averaged Navier-Stokes) modeling. The analysis is performed for the NASA's hump configuration which is the combination of a flat plate and a hump. This configuration was used in NASA's flow control workshop and it was one of validation cases for RANS and LES simulations. The separation occurs at the 65% of model length where a slot is positioned for the flow control. No flow control case and steady suction case are studied using RANS modeling. The Spalart-Allmaras model and the SST(Shear Stress Transport) model are applied and their accuracy are compared. To correlate CFD analysis with experimental data, the optimal boundary condition was investigated and the effect of a cavity around the slot is studied for the no flow case.

A Study on the Impact Analysis of Security Flaws between Security Controls: An Empirical Analysis of K-ISMS using Case-Control Study

  • Kim, Hwankuk;Lee, Kyungho;Lim, Jongin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.9
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    • pp.4588-4608
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    • 2017
  • The measurement of information security levels is a very important but difficult task. So far, various measurement methods have studied the development of new indices. Note, however, that researches have focused on the problem of attaining a certain level but largely neglecting research focused on the issue of how different types of possible flaws in security controls affect each other and which flaws are more critical because of these effects. Furthermore, applying the same weight across the board to these flaws has made it difficult to identify the relative importance. In this paper, the interrelationships among security flaws that occurred in the security controls of K-ISMS were analyzed, and the relative impact of each security control was measured. Additionally, a case-control study was applied using empirical data to eliminate subjective bias as a shortcoming of expert surveys and comparative studies. The security controls were divided into 2 groups depending on whether or not a security flaw occurs. The experimental results show the impact relationship and the severity among security flaws. We expect these results to be applied as good reference indices when making decisions on the removal of security flaws in an enterprise.

Development of Coordinated Scheduling Algorithm and End-to-end Delay Analysis for CAN-based Distributed Control Systems (CAN기반 분산 제어시스템의 종단 간 지연시간 분석과 협조 스케줄링 알고리즘 개발)

  • 이희배;김홍열;김대원
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.7
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    • pp.501-508
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    • 2004
  • In this paper, a coordinated scheduling algorithm is proposed to reduce end-to-end delay in distributed control of systems. For the algorithm, the analysis of practical end-to-end delay in the worst case is performed priory with considering implementation of the systems. The end-to-end delay is composed of the delay caused by multi-task scheduling of operating systems, the delay caused by network communications, and the delay caused by asynchronous timing between operating systems and network communications. Through some simulation tests based on CAN(Controller Area Network), the proposed worst case end-to-end delay analysis is validated. Through the simulation tests, it is also shown that a real-time distributed control system designed to existing worst case delay cannot guarantee end-to-end time constraints. With the analysis, a coordinated scheduling algorithm is proposed here. The coordinated scheduling algorithm is focused on the reduction of the delay caused by asynchronous timing between operating systems and network communications. Online deadline assignment strategy is proposed for the scheduling. The performance enhancement of the distributed control systems by the scheduling algorithm is shown through simulation tests.

An Automatic Diagnosis for Rotor Bar Faults using Park's vector Pattern (팍스벡터 패턴을 이용한 회전자 바 고장 자동 진단)

  • Song, Myung-Hyun;Park, Kyu-Nam;Han, Dong-Gi;Yang, Chul-Oh
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.361-363
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    • 2007
  • In this paper, an auto-diagnosis method of rotor bar fault for small induction motor is suggested. Usually FFT of stator currents are given the good results, but to detect the fault, slip is needed for calculating the feature frequency. The slip is varied as the load is changed. So in this paper, some alternative method for estimating the load is suggested. This method is based on the Park's vector pattern. The magnitudes of the feature frequency are compared with the threshhold that is predefined in the bounded range of load. The healthy rotor, single rotor bar fault and double rotor bar fault are tested with no load, 25%, 50%, 75%, and 100% rated load. From 50% to 100% rated load case, the rotor bar faults are detectable using indirect estimation of the load and the comparing the magnitudes of feature frequency. The no load case and under 40% rated load case, rotor fault are un detectable.

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A Case-Control Study on the Relationship between Obesity and Female Colorectal Cancer (여성 대장암 발생과 비만의 관련성에 관한 환자-대조군 연구)

  • Shin, Ae-Sun;Yoon, Ha-Chung;Yoo, Keun-Young
    • Journal of Preventive Medicine and Public Health
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    • v.35 no.2
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    • pp.147-152
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    • 2002
  • Objectives : A hospital-based case-control study was conducted to evaluate the role of obesity in the development of colorectal cancer. Methods : Three hundred and twenty four histologically confirmed female colorectal cancer cases and 26,998 non-cancer controls were selected from patients invited to the Aichi Cancer Center, Nagoya, Japan between 1989 and 1995. Information concerning demographic factors, medical history, family medical history, reproductive factors and dietary factors were obtained from self-administered questionnaires and medical records. The effects of weight and body mass index to colorectal cancer were examined using multiple logistic regression to control for other risk factors. Results : There was no significant association between female colorectal cancer and obesity. Heavier weight adjusted for height or body mass index did not increase the risk of colorectal cancer. Conclusions : These results suggest that there is no association between colorectal cancer risk and obesity in women.

Effect of an Ankle Strengthening Exercise that Uses PNF on the Balance and Walking Ability of Patients with Acute Disseminated Encephalomyelitis -A Single Case Study- (PNF를 이용한 발목 강화 운동이 급성파종성 뇌척수염 환자의 균형 및 보행 향상에 미치는 영향 -단일사례연구-)

  • Jung, Du-Kyo
    • PNF and Movement
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    • v.15 no.1
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    • pp.85-96
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    • 2017
  • Purpose: Peripheral neuropathy accompanied by sensory disturbance, such as limb paralysis and hemiplegia, is mainly caused by acute disseminated encephalomyelitis (ADEM). This case study aimed to determine the effect of ankle strengthening exercises that use proprioceptive neuromuscular facilitation (PNF) on the gait, balance, ankle-control ability, and sit-to-stand ability on a patient with ADEM. Methods: A 10-year-old male with quadriplegia and ankle-control impairment participated in this 4-week training intervention. The patient, diagnosed with ADEM, was treated with ankle strengthening exercises that used PNF. Results: The patient demonstrated improvements in balance, ankle-control ability, sit-to-stand ability, and gait performance. Outcome measures (manual muscle test, modified Ashworth scale, sensory assessment, coordination assessment, Berg balance scale, 5 time sit-to-stand test, and 10 m walk test) were taken before and after the training program. Conclusion: The results of this case suggest that an ankle strengthening exercise that uses PNF can improve the gait, balance, ankle-control ability, and sit-to-stand ability in patients with ADEM. In ADEM, the initial treatment is important, and the use of ankle strengthening exercises with PNF could lead to meaningful results. However, there is limited research due to an insufficient number of cases. In the future, more patients will need to be studied.

Implementation of web server monitoring system using crawling technology

  • Yu, Young-Geun;Nam, Ki-Bok;Park, Koo-Rack
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.4
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    • pp.123-128
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    • 2019
  • In modern society, there are WEB sites that provides information in various fields by many advances in IT technology. As the number of users accessing the Web increases, one server becomes unavailable, and multiple servers are deployed to provide the service. In addition, systems that control servers are required to manage multiple servers. However, server control systems in the existing market are mostly those that notify managers through SMS and apps when a server's down or a controlled port is closed. However, in case of servers that generate a lot of traffic, the Web server and the WAS are operated and managed each independently. The WEB and WAS provide service by connecting to each other. However, the connection between WEB and WAS may be disconnected due to various environmental factors. In this case, the existing control system can not determine whether the service is working properly. Even in the case of WEB and WAS of a server that is operated independently, there is a phenomenon that the existing control system does not know the problem even when the normal service is not provided due to environmental factors such as disconnection to DB. In this paper, we implemented a system to check the normal state of Web service using Web crawling to solve this problem.