• Title/Summary/Keyword: case-control studies

Search Result 1,586, Processing Time 0.028 seconds

Stability of Sensorless Speed Control of PMSM Using State Observer (상태관측기를 이용한 영구자석 동기전동기의 센서리스 속도제어의 안정도)

  • Son, M.K.;Lee, D.H.;Lee, H.J.;Kwon, Y.A.
    • Proceedings of the KIEE Conference
    • /
    • 1998.07a
    • /
    • pp.12-14
    • /
    • 1998
  • Sensorless PMSM is much studied for the industrial applications and home appliances because a mechanical sensor reduces reliability and increases cost. This paper studies the stability of sensorless speed control of PMSM using state observer. Sensorless control scheme using state observer is known as a scheme having a comparatively good performance. Several papers have studied the stability of state observer control scheme, but have not considered parameter variation which is important to sensorless control. This paper studies the stability through computer simulation in case of parameter variation.

  • PDF

Stressful Life Events and Risk of Colorectal Cancer: A Case-Control Study of Iran

  • Azizi, Hosein;Esmaeili, Elham Davtalab
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.16 no.6
    • /
    • pp.2403-2407
    • /
    • 2015
  • Background: Very few analytical studies are available on any association between stressful life events (SLE) and colorectal cancer (CRC), at least in Iran. The aim of this case control study was to determine the association between stressful life events (SLE) and colorectal cancer. Materials and Methods: This study was conducted in four hospital colonoscopy units in Tabriz city of Iran including 414 participants aged 40-75 years: 207 cases with CRC confirmed by pathology and colonoscopy findings and 207 controls free of neoplastic conditions were selected (from the same hospitals at the same period for the cases and after matching for age and sex). Stressful life events were assessed using a 43-item Holmes and Rahe Life Events Questionnaire. Multivariate logistic regression was used to estimate adjusted odds ratios for SLE and risk of CRC. Results: The stressful life event mean score in the case group was 141.3, in contrast to 63.8 in the control group (p<0.011). After adjusting for confounders, death of dear ones increased the risk of CRC (OR: 2.49; 95%CI: 1.41-5.13). Other types of stressful life events (family and husband disputes, serious occupational problems, unemployment of > 6 months, and Serious financial problems) were also associated with CRC, but without statistical significance. Conclusions: According to our findings, it seems that SLE may increase the risk of CRC.

A Review of Research on Electroacupuncture for Female Stress Urinary Incontinence (여성 복압성 요실금에 대한 전침치료 연구 동향)

  • Park, Eo-Jin;Jo, Hyun-Jeong;Jo, Hee-Guen
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.30 no.4
    • /
    • pp.149-174
    • /
    • 2017
  • Objectives: The aim of this study is to establish a base for further research by reviewing studies on electroacupuncture (EA) for stress urinary incontinence (SUI). Methods: Clinical studies concerning the effects of EA for SUI, were obtained from Cochrane Library, PubMed, CNKI, RISS, NDSL, KISS and OASIS. Results: Forty-five studies met the criteria, which included 33 RCTs, 1 pilot RCT, 4 non-randomized Clinical Trials, 6 Case studies and 1 Orthogonal design study with 3638 patients. There was only one article published in Korea. In these study, the most common primary outcome measurement was the pad test. Most of the studies showed the group treated by EA effects compared to the control group. Also, many interventions that combined with EA were found and all complex therapy group had significantly better than control group. 7 studies observed adverse events (AEs), four of which referred to EA related AEs among them. And 4 studies reported no AEs associated with EA. Conclusions: Despite several limitations, various studies to prove limited yet effective EA on SUI provides much significance. Subsequent studies conducted by the complementary systematic review of the studies and well-designed clinical trials using the methodological quality will be needed to more firmly validate the therapeutic effect of EA on SUI.

Identification of Genetic and Non-genetic Risk Factors for Nasopharyngeal Carcinoma in a Southeast Asian Population

  • Hashim, Nikman Adli Nor;Ramzi, Nurul Hanis;Velapasamy, Sharmila;Alex, Livy;Chahil, Jagdish Kaur;Lye, Say Hean;Munretnam, Khamsigan;Haron, Mohd Roslan;Ler, Lian Wee
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.12
    • /
    • pp.6005-6010
    • /
    • 2012
  • Background: Nasopharyngeal carcinoma (NPC) is endemic in Southern Chinese and Southeast Asian populations. Geographical and ethnic clustering of the cancer is due to genetic, environmental, and lifestyle risk factors. This case-control study aimed to identify or confirm both genetic and non-genetic risk factors for NPC in one of the endemic countries, Malaysia. Materials and Methods: A panel of 768 single-nucleotide polymorphisms (SNPs) previously associated with various cancers and known non-genetic risk factors for NPC were selected and analyzed for their associations with NPC in a case-control study. Results: Statistical analysis identified 40 SNPs associated with NPC risk in our population, including 5 documented previously by genome-wide association studies (GWAS) and other case-control studies; the associations of the remaining 35 SNPs with NPC were novel. In addition, consistent with previous studies, exposure to occupational hazards, overconsumption of salt-cured foods, red meat, as well as low intake of fruits and vegetables were also associated with NPC risk. Conclusions: In short, this study confirmed and/or identified genetic, environmental and dietary risk factors associated with NPC susceptibility in a Southeast Asian population.

The Worst-Case Optimal Design of An Interface Circuit for Satellite (Worst Case를 고려한 위성체 접속회로의 최적설계)

  • Lho, Yeung-Hwan;Lee, Sang-Yong
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.8 no.2
    • /
    • pp.136-141
    • /
    • 2002
  • The electrical characteristics of solid state devices such as BJT(Bipolar Junction Transistor) and MOSFET, etc, are altered by impinging nuclear radiation and temperature in the space environment. This phenomenon is well known and has been studied extensively since the early 1960's when satellites were first being designed and used in the United States. However, the studies and the developments of radiation hardening technologies for the electronic components at the industrial fields in our country has not been popular so far. The worst case design technology in the electrical circuit is required for the appropriate operation of solid state devices in the space environment. In this paper, the interface circuit used in KOMPSAT(Korea Multipurpose Satellite), which is now being operated since the one was launched in 1999, is optimally designed to accomodate the worst case design and radiation effect.

The Effects of Case Management Program for Diabetic Patients - Focused on Medium-sized Industrial Workers - (당뇨병 대상자에게 실시한 사례관리 프로그램의 효과 - 중규모 사업장 근로자를 중심으로 -)

  • Hwang, Hyun-Jung;Jung, Hye-Sun
    • Korean Journal of Occupational Health Nursing
    • /
    • v.19 no.2
    • /
    • pp.258-267
    • /
    • 2010
  • Purpose: This paper studies the influence of the case-management program on the change of blood sugar, lifestyle, and knowledge level of diabetes mellitus (DM) for medium-sized-enterprise employees suffering from DM. Method: Subjects, divided into experimental and control groups, are 59 workers with FBS higher than 126mg/$d{\ell}$ or under DM medication treatment in the medium-sized enterprises, being managed by two distinct university hospital group occupational health management service teams. The case management program for DM patients consists of 6 different processes in which each subject is treated. Result: FBS decreased in the experimental group after the program, while that of the control group increased significantly. In the experimental group, the amount of smoking, the frequency of drinking and the amount of drinking per week decreased. Also, the knowledge level for DM and the change of nutrition management showed significant increase. In the control group, the amount of smoking increased and the frequency of drinking, the amount of drinking and nutrition level did not change significantly. And the knowledge level for DM decreased. Conclusion: We expect that taking this case management program for DM management may significantly improve diabetic patients' overall health.

A Review Study of Scalp Acupuncture for Parkinson's Disease in China (중국에서의 파킨슨병 두침치료 임상연구 논문분석)

  • Kim, Woo-Kyung;Kim, Lak-Hyung;Jang, In-Soo
    • Journal of Oriental Neuropsychiatry
    • /
    • v.22 no.4
    • /
    • pp.11-20
    • /
    • 2011
  • Objectives : The purpose of this study was to obtain some knowledge about the scalp acupuncture treatment on Parkinson's disease for the future practice and the research from the clinical studies in China. Methods : The literatures were searched using the database-China Academic Journals(CAJ) (2006-2011). Clinical studies of scalp acupuncture for Parkinson's disease-Randomized controlled trial(RCT), case control study, case series, case report- were included. Results : Of 65 articles, 12 Clinical studies met our inclusion criteria. Three case series reported a significant improvement in the patients with Parkinson's disease by scalp acupuncture, and 9 RCTs reported a significant effectiveness of scalp acupuncture as a monotherapy or as a combination therapy with Madopa Tablet(Levodopa + Benserazide HCl) treatment. Conclusions : The results of this study could be used for the future study about scalp acupuncture for Parkinson's disease.

Case Studies of a Performance-Based Contract for National Highway Pavement Maintenance (성능보증제도를 적용한 일반국도 유지보수공사 시범사업)

  • Lim, Jaekyu;Kim, Yongjoo;Kim, Myeongil;Lee, Jaejun
    • International Journal of Highway Engineering
    • /
    • v.20 no.1
    • /
    • pp.1-8
    • /
    • 2018
  • PURPOSES : Case studies of an asphalt-overlay project with a performance-based contract method were conducted on a national highway in Korea to evaluate the effect of the method on asphalt pavement maintenance. This study evaluated the procedure of the performance-based contract method. METHODS : In this study, an asphalt-pavement maintenance project for a national highway was assessed with a performance-based contract to investigate the advantage of the new contract procedures. This is the first trial applying the performance-based contract to a pavement-rehabilitation project in Korea. In the four case studies, the warranty period of the performance-based contract was designed for seven years. The research team monitored the construction site to compare the normal contract method with the performance-based contract method. The case studies' project sites were investigated after the end of the construction. RESULTS : Based on the limited case studies, the performance-based contract method could extend the service life of the asphalt pavement and reduce the pavement-maintenance budget because the quality control was well managed by the contractors. However, a few construction laws would be necessary to apply the performance-based contract method in the future. CONCLUSIONS : Using the performance-based contract, the construction company made great efforts to guarantee the warranty period and to apply the optimal maintenance method, based on the pavement distress condition. The contractor and the agency would need to understand the new performance-based contract system for it to be activated. Therefore, a proper education program for the performance-based contract system would be needed to educate the stakeholders regarding the procedures and their effects on the pavement management and maintenance.

Association Between Green Tea and Colorectal Cancer Risk: A Meta-analysis of 13 Case-control Studies

  • Wang, Xue-Jun;Zeng, Xian-Tao;Duan, Xiao-Li;Zeng, Huan-Chao;Shen, Rui;Zhou, Ping
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.13 no.7
    • /
    • pp.3123-3127
    • /
    • 2012
  • Objective: Experimental studies have suggested green tea to be a chemopreventive agent for colorectal cancer, and many studies have examined possible associations. However, the conclusions were inconsistent or even contradictory, so we performed a meta-analysis based on published case-control studies to explore if green tea is indeed a protective factor. Methods: PubMed was searched up to May $10^{th}$, 2012 for relevant studies, and references of included studies were manually searched. Finally 13 eligible studies, involving 12,636 cases and 38,419 controls were identified. After data extraction, a meta-analysis was performed using CMA v2 software. Results: The results indicated there may be a weak but not statistically significant reduced risk of colorectal cancer with high dose of green tea intake (OR=0.95, 95% CI:0.81-1.11, p=0.490.69-0.98). This protective effect was also found in all subgroups, except in American and European populations. Sensitivity analysis indicated the result to be robust. Publication bias was not detected by either funnel plot or Egger tests. Conclusion: The results of this meta-analysis indicate a weak lower tendency for colorectal cancer development with green tea consumption, but available epidemiologic data are insufficient to conclude that green tea may protect against colorectal cancer in humans.

A Study of on the Optimal Vaccinaton using Pontryagin's Minimum Principle (Pontryagin 최소 원리를 이용한 최적접종에 관한 연구)

  • Jeong, Hyeong-Hwan;Ju, Su-Won;Lee, Gwang-U
    • Journal of Biomedical Engineering Research
    • /
    • v.9 no.1
    • /
    • pp.11-16
    • /
    • 1988
  • The optimum control theory has been applied to the problem of finding the most economic use of active and passive immunization controls. Application of Pontryagin's Minimum Principle to this case, involving functions of delayed control has been demonstrated and a procedure has been developed for the numerical solution of the resulting control problem. Using the numerical procedure, optimum control strategies have been obtained for different values of reported case cost.

  • PDF