• 제목/요약/키워드: case control studies

검색결과 1,582건 처리시간 0.027초

Studies on Starting Transient in Solid Rockets

  • V.R. Sanal Kumar;Kim, Heuy-Dong
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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    • pp.6-10
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    • 2003
  • Accurate description of starting transient history allows and justifies the use of small margin of safety for the engine parts, resulting in high motor mass ratio in addition to satisfying the control and guidance requirements of the vehicle. Studies have been carried out for the prediction and reduction of ignition peak and pressure-rise rate during the starting transient of solid rocket motors. Numerical studies have been carried out using a two dimensional Navier-Stokes solver. It has been inferred through the parametric studies that, in the case of solid rocket motors with uniform port, high ignition peak is observed at high spread rate and low pressure-rise rate. In the case of the port with sudden expansion configuration, high ignition peak is observed at relatively high average spread rate and high-pressure rise rate. These studies are expected to aid the designer in reducing the ignition peak by altering the propellant properties or igniter characteristics without sacrificing the motor performance.

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야뇨증에 대한 전침치료 동향 (1994-2010년 중국 임상 논문 중심으로) (A Review of Electroacupuncture on Patients with Nocturnal Enuresis in Chinese Medicine)

  • 성원영;김락형
    • 동의신경정신과학회지
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    • 제21권4호
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    • pp.69-78
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    • 2010
  • Objectives : The study was designed to evaluate the effect of electro acupuncture on patients with nocturnal enuresis in China. Methods: We performed systematic reviews of case reports and case-control studies of electroacupuncture on patients with nocturnal enuresis published from 1994 to 2010 in CNKI(中國知識基礎施設工程 http://www.cnki.net) at September, 2010. Results: 18 studies were selected. The electroacupuncture points frequently used were Chungguk (中極), Kwanwon(關元), Samumgyo(三陰交), Shinsu(腎兪). Bangkwangsu(膀曠兪), etc. G6805 electroacupuncture instrument was most frequently used in those studies and the treating methods of electro acupuncture were various according to each study. The combination of electroacupuncture and other therapy showed better results than the simple therapies such as simple electro acupuncture or acupuncture. western medicine. herbal medicine. auricular therapy. Conclusions : There have been 18 studies of electro acupuncture on patients with nocturnal enuresis in China and these studies can be applied to the clinical practices in Korea.

안면마비의 테이핑 요법에 대한 임상 연구 동향 (Clinical Research Trend for Taping Therapy on Facial Palsy)

  • 이규영
    • 한방안이비인후피부과학회지
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    • 제36권4호
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    • pp.70-87
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    • 2023
  • Objectives : The purpose of this research is to review the efficacy and safety of taping therapy for facial palsy. Methods : Two foreign databases(Pubmed, CNKI) and one domestic database(OASIS) were used to search, and papers retrieved from the starting point of literature provision in each database until June 19, 2023 were included in the study. All studies in which other treatments were performed as a treatment intervention along with taping therapy were included, but cases where taping therapy was a comparative intervention were excluded. Results : 18 studies were selected. 14 studies were two-arm randomized controlled trials(RCT), and 4 studies were case reports. There was improvement in facial palsy in all 4 case reports, and in all 14 RCTs, the treatment effect in the observation group was significantly higher than in the control group. Conclusions : Taping therapy can be an effective and safe treatment method for facial palsy. However, the risk of bias in the selected studies was high, and there were many cases in which multiple interventions other than taping therapy were applied simultaneously. Therefore, well-designed studies with high quality are needed in the future.

제방의 조사 기술에 관한 고찰 (Case Studies on Investigation Technologies on Embankments)

  • 양태선;김진만;최봉혁;김주현
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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    • pp.680-688
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    • 2008
  • On behalf of hazard mitigation, cases of investigation methods on levee are described. In general, failures of levee are caused by piping, water leakage through ground under the levee in Kimpo, Ilsan etc. Several phenomena against levees should be protected through consideration of analysis and quality control stage during construction. In this paper, protection methods against failures should be investigated by case studies.

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저속 장행정 박용디젤기관의 속도제어에 관한 연구 (A STUDY ON THE SPEED CONTROL OF A LOW SPEED-LONG STROKE MARINE DIESEL ENGINE)

  • 유영호;하주식
    • Journal of Advanced Marine Engineering and Technology
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    • 제13권3호
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    • pp.26-36
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    • 1989
  • Recently digital governor system is commonly adapted for the speed control of the marine diesel engine because of too much fluctuation of rpm resulted by the low speed, long stroke, high efficiency and a small number of cylinder of it, and versatile studies on the development of digital governor system are progressed. On this subject the new control method in which the fuel is controlled by feedforwarding the change of load as well as the feedback of angular velocity in case of disregarding the engine dead time and influence of scavenging air was proposed by the authors, and found the method has shown quite a good control performance in comparision to the conventional control method by the simulation using a digital computer for various load change. In this paper the speed control system of a diesel engine is simulated in case of regarding the engine dead time by the proposed method, and also confirm a good control performance of it under even more realistically simulated environment.

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환경변인 및 내적통제력, 부모와의 의사소통이 청소년의 스트레스에 미치는 영향 -농촌, 도시비교- (Influence of environmental variables, inner control and communication with parents on adolescent's stress -compared rural with urban-)

  • 백양희
    • 대한가정학회지
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    • 제35권2호
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    • pp.33-47
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    • 1997
  • The purpose of the study is to examine the differences between rural and urban in the factors and the level of stress in adolescent, inner control and communication with parents. Also, It is to research the influence of environmental variables, inner control and communication with parents on adolescent's stress in sides of rural and urban. Therefore, I provide needed data in instructing students. For the data set, academic high school students in second grade in a town for rural and Su-Seung gu, Dal-Sugu, chung gu in Dae-gu for urban were chosen. The data were analyzed with the frequency, percentage, factor analysis Mean, S.D, reliability, t-test, regression in use of Spss PC+ Program. The main results are as follow. First, for rural students, stress level is displayed studies, future0affair, life-attitude, companions, self-assurance and home life in order by lower sphere. For urban students, it is displayed future-affair, studies, life-attitude, companions, self-assurance and home life in order by lower shpere. In case of rural "I don't know effective study method" is highly displayed by factors. In case of urban. "I am tired of a competitive life" is highly displayed. The mean of stress level is 3.22 for rural and 3.07 for urban. The differences between rural and urban are showed in self-assurance, studies and companions. Finally when we see the stress generally the stress level is higher in rural high school students than in urban high school students. Second, rural students are lower displayed than urban students in inner control and communication with parents. There is no difference urban students in inner control and communication with parents. There is no difference in communication with a mother. third, influential variables on stress level are inner control, communication with parents, satisfaction with companions and school life as environmental variables in sides of rural and urban. Physical condition is added for rural and sex for urban Finally we get the result that stress level is high in low inner control, poor communication with parents, bad companions and unsatisfied school life for both rural and urban. Bad physical condition for rural and female for urban are added.

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직접구동 SCARA 로봇 머니퓰레이터에 대한 적응견실제어 (Adaptive robust control for a direct drive SCARA robot manipulator)

  • 이지형;강철구
    • 한국정밀공학회지
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    • 제12권8호
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    • pp.140-146
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    • 1995
  • In case the uncertainty existing in a system is assumed to satisfy the matching condition and to be come-bounded. Y. H. Chen proposed an adaptive robust control algorithm which introduced adaptive sheme for a design parameter into robust deterministic controls. In this paper, the adaptive robust control algorithm is applied to the position tracking control of direct drive robots, and simulation and experimental studies are conducted to evaluate control performance.

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자하거 약침의 신경정신과 임상 응용에 관한 체계적 문헌 고찰 (A Systematic Review of Placenta Pharmacopuncture for Neuropsychiatric Diseases in Practice)

  • 신혜규;이재혁;강형원
    • 동의신경정신과학회지
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    • 제33권2호
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    • pp.157-180
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    • 2022
  • Objectives: To perform a systematic review of placenta pharmacopuncture for treating neuropsychiatric diseases, focusing on its efficacy and the safety so that evidence on its clinical use could be obtained, thus contributing to further studies. Methods: Through Korean, English, and Chinese databases (OASIS, Korean TK, KISS, RISS, ScienceON, Pubmed, Cochrane, EMBASE, CINAHL, AMED, CNKI, and Wanfang), combinations of keywords (placenta, pharmacopuncture, etc.) were used to select clinical studies published until January 2021 about placenta pharmacopuncture for neuropsychiatric diseases. Interventions included combined treatments. Study design included cases studies, series, and clinical trials. Cohort studies, literature reviews, in vitro and animal experiments were excluded. The primary outcomes involved measurements of symptoms, Visual Analogue Scale, or questionnaires. Data extracted from databases were imported to Endnote X7 to remove duplicates. The quality of the literature was assessed based on CAse REports Guidelines and Cochrane's Risk of Bias (ROB). Results: Twenty-one studies were selected, including ten case reports, three case series, two one-armed clinical trials, one non-randomized clinical trial, and five randomized clinical trials. There were six studies on sleep disorders, five studies on stroke sequela, two on mood disorders, two on enuresis, two on Guillain-Barré syndrome, two on multiple sclerosis, one on neurocognitive disorder, and one on vertigo. The most frequent combined treatment was acupuncture in both the experimental group (n=10) and the control group (n=3). Acupoints were ST36, SP6, BL23, CV4, GB20, GV20, N-HN54, and so on. All studies reported improvement of symptoms. The quality of case studies was relatively high. Assessment of ROBs resulted in low risks. Conclusions: Placenta pharmacopuncture is effective for neuropsychiatric diseases such as sleep disorders, mood disorders, enuresis, and neurocognitive disorders. Regarding insomnia, several studies have reported significant improvements with placenta pharmacopuncture. There was no adverse event associated with placenta pharmacopuncture.

메니에르 병의 침 치료에 관한 최근 임상 연구 동향 (Recent Clinical Research Trends on Acupuncture Treatment of Meniere's Disease)

  • 이규영;홍철희
    • 한방안이비인후피부과학회지
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    • 제31권3호
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    • pp.26-38
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    • 2018
  • Objectives : The purpose of this study is to investigate the possibility of applying acupuncture to the treatment of meniere's disease, which has no definite treatment methods, by analyzing the latest clinical researches about acupuncture treatment of meniere's disease. Methods : A case study and Randomized Controlled Trial (RCT) related to the acupuncture treatment of meniere's disease were searched using domestic and international thesis search engines including OASIS, CNKI, J-STAGE, PubMed. This study include acupuncture treatment and acupuncture combined with other treatments such as herbal medicine. The search was limitied to the publication date from 2000 to 2018 with free full text. Results : 17 cases were selected. There were 7 case studies in Korea, 5 case studies in China, and 5 RCT papers in China. All 12 cases reported improvement in meniere's disease and all RCT studies showed significantly higher treatment effects in the experimental group than in the control group. Conclusions : Acupuncture treatment showed significant effects for meniere's disease when applied alone or in combination with other treatments. In the future, various systematic studies should be conducted only for acupuncture treatment.

Hormone Replacement Therapy and Risk of Breast Cancer in Korean Women: A Quantitative Systematic Review

  • Bae, Jong-Myon;Kim, Eun Hee
    • Journal of Preventive Medicine and Public Health
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    • 제48권5호
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    • pp.225-230
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    • 2015
  • Objectives: The epidemiological characteristics of breast cancer incidence by age group in Korean women are unique. This systematic review aimed to investigate the association between hormone replacement therapy (HRT) and breast cancer risk in Korean women. Methods: We searched electronic databases such as KoreaMed, KMbase, KISS, and RISS4U as well as PubMed for publications on Korean breast cancer patients. We also conducted manual searching based on references and citations in potential papers. All of the analytically epidemiologic studies that obtained individual data on HRT exposure and breast cancer occurrence in Korean women were selected. We restricted the inclusion of case-control studies to those that included age-matched controls. Estimates of summary odds ratio (SOR) with 95% confidence intervals (CIs) were calculated using random effect models. Results: One cohort and five case-control studies were finally selected. Based on the heterogeneity that existed among the six studies (I-squared=70.2%), a random effect model was applied. The summary effect size of HRT history from the six articles indicated no statistical significance in breast cancer risk (SOR, 0.983; 95% CI, 0.620 to 1.556). Conclusions: These facts support no significant effect of HRT history in the risk of breast cancer in Korean women. It is necessary to conduct a pooled analysis.