• Title/Summary/Keyword: Systematic study

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Experimental Investigations of Systematic Errors in Wind Tunnel Testing Using Design of Experiments (실험설계법 기반 풍동시험 시스템 오차 검출 실험연구)

  • Oh, Se-Yoon;Park, Seung-O;Ahn, Seung-Ki
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.5
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    • pp.335-341
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    • 2013
  • The variation of systematic bias errors in the wind tunnel testing has been studied. A Design of Experiments(DOE) approach to an experimental study of fuselage drag and stability characteristics of a helicopter configuration was applied. When forces and moments measured in one time block differ significantly from measurements made in another time block under assumption that sample observations can be expected to yield same results within permissible measuring errors. The practical implication of this paper is that the systematic error can not be assumed not to exist. The those error reduction could be achieved through the process of randomization, blocking, and replication of the data points.

The Relationship between Early-onset Androgenetic Alopecia and Metabolic Syndrome: Systematic Review and Meta-Analysis (조발성 탈모증과 대사증후군과의 관계: 체계적 문헌고찰 및 메타분석)

  • Jang, Jin-Young;Yoon, Young-Joon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.30 no.3
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    • pp.166-181
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    • 2017
  • Objectives : The study was done to verify the relation between early-onset androgenetic alopecia(AGA) and metabolic syndrome(MetS). Methods : Data were collected through electronic database including KoreaMed, National Assembly Library, KMBASE, NDSL, KCI, KERIS, Google Scholar, Pubmed, Cochrane CENTRAL and EBSCO MEDLINE. A total of 13 case-control studies related to the MetS of early-onset alopecia patients were used for the systematic review and meta-analysis. Risk of bias of included studies were assessed by RoBANS tool. RevMan5.3, CMA3 were used for the meta-analysis. Results : In 13 evaluated articles, most frequent bias was the participant selection bias that was found in 10 articles. Significant association between early-onset AGA and MetS was found in 10(76.9%) out of 13 articles in the systematic review. In meta-analysis, early-onset male AGA was associated with increased risk of metabolic syndrome(OR: 3.73, 95% CI:2.49 -5.61). Conclusions : AGA, particularly early -onset male AGA, is significantly associated with MetS. Therefore all patients with early onset male AGA should be suggested to take preventive treatment to reduce the risk of MetS and various problems associated with it.

Do universal adhesives promote bonding to dentin? A systematic review and meta-analysis

  • Elkaffas, Ali. A.;Hamama, Hamdi H.H.;Mahmoud, Salah H.
    • Restorative Dentistry and Endodontics
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    • v.43 no.3
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    • pp.29.1-29.13
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    • 2018
  • Objectives: The aims of this study were to conduct a systematic review of the microtensile bond strength (${\mu}TBS$) of multi-mode adhesives to dentin and to perform a meta-analysis to assess the significance of differences in the ${\mu}TBS$ of one of the most commonly used universal adhesives (Scotchbond Universal, 3M ESPE) depending on whether the etch-and-rinse or self-etch mode was used. Materials and Methods: An electronic search was performed of MEDLINE/PubMed, ScienceDirect, and EBSCOhost. Laboratory studies that evaluated the ${\mu}TBS$ of multi-mode adhesives to dentin using either the etch-and-rinse or self-etch mode were selected. A meta-analysis was conducted of the reviewed studies to quantify the differences in the ${\mu}TBS$ of Scotchbond Universal adhesive. Results: Only 10 studies fulfilled the inclusion criteria for the systematic review. Extensive variation was found in the restorative materials, testing methodologies, and failure mode in the reviewed articles. Furthermore, variation was also observed in the dimensions of the microtensile testing beams. The meta-analysis showed no statistically significant difference between the etch-and-rinse and self-etch modes for Scotchbond Universal adhesive (p > 0.05). Conclusions: Multi-mode 'universal' adhesives can achieve substantial bonding to dentin, regardless of the used modes (either etch-and-rinse or self-etch).

Clinical application of a new systematic implant planning concept: A Clinical Report

  • Jeong, Seung-Mi;Chung, Chae-Heon;Engelke, Wilfried
    • The Journal of Korean Academy of Prosthodontics
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    • v.38 no.6
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    • pp.814-820
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    • 2000
  • Statement of Problem. Commonly used classification systems do not inform for dentists the dimension of the available bone at a potential implant site although regarding a variety of morphologic and pathophysiologic aspects using schematic graphs. However, for the implantologist the availability of bone substance is most important independent whether it concerns the jaw basis or the alveolus. Purpose of Study. The present article refers to a new evaluation form, to analyze the available bone with regard to optional immediate loading site by site. According to a new systematic implant planning concept will be presented in two case reports. Results. The feasibility of the classification for planning and documentation of immediately loaded implants is presented in two case reports. Conclusion. The factor of bone support for immediate functional stability is important in dental implantology. The new systematic implant planning helps to systematically estimate the dimension (ASCIi classification) of the alveolus site by site to evaluate the possibility of immediate loading. The Gottingen classification thus aids to determine the degree of stability that can be expected for the planned solution.

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Assessment Tools for the Mental Health of School-Aged Children and Adolescents Exposed to Disaster: A Systematic Review (1988-2015)

  • Lee, Mi-Sun;Bhang, Soo-Young
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.29 no.3
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    • pp.88-100
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    • 2018
  • Objectives: In this study, we aimed to conduct a systematic review of studies investigating psychosocial factors affecting children exposed to disasters. Methods: In total, 140 studies were retrieved. The studies were published from 1988 to 2015. A systematic review was performed using the PRISMA guidelines. MEDLINE, EMBASE, Cochrane Central, Web of Science, PsycINFO, PubMed, and Google Scholar were searched. Each database was searched using the following terms: 'Child,' 'Adolescent,' 'Youth,' 'Disaster,' 'Posttraumatic,' 'Psychosocial,' 'Assessment,' 'Evaluation,' and 'Screening.' The identified studies were subjected to data extraction and appraisal. Results: The database search identified 713 articles. Based on the titles and abstracts, the full texts of 118 articles were obtained. The findings of this review can be used as a basis for the design of a psychosocial evaluation tool for disaster preparedness. Conclusion: Given the paramount importance of post-disaster evaluation and the weaknesses of current disaster evaluation tools, the need to develop valid and reliable tools and psychometric evaluations cannot be overstated. Our findings provide current evidence supporting various assessments in children, who are very vulnerable psychologically following disasters.

Study on Application of Real Time AIS Information

  • Hori, Akihiko;Arai, Yasuo;Okuda, Shigeyuki
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2006.10a
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    • pp.63-70
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    • 2006
  • Now AIS (Automatic Identification System) has been under full operation for ocean-going vessels, and it is expected not only to identify target ships but also to take collision avoidance using AIS information with Radar and ARFA information in restricted waters. AIS information is very useful not only for target identifications but also for taking collision avoidance, but OOW (Officer OF Watch-keeping) should take care of systematic observation of AIS because of miss-operation or malfunction of AIS. In this paper, we propose the application of Onboard Ship Handling Simulator with visual system displayed 3D scene added AIS performance such as blind areas of Island, microwave propagation, ok. and maneuvering simulation using TK models, applied real time AIS information and research the effectiveness of this system for ship handling in restricted waters, and discus the principal issues through the on board experiments. Conclusion will be expected that; 1) systematic observation of ASS information using visual scene simulator with AIS information will be effectively done, 2) observation compared with Radar and ARPA information will be also useful to make a systematic observation, 3) using the recording and replay function of simulation will be useful not only for systematic observation but also to measure and to encourage officers' skill.

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Virtual In-situ Sensor Calibration and the Application in Unitary Air Conditioners (유닛형 공기조화기 센서의 가상보정 방법 및 적용 특성 분석)

  • Yoon, Sungmin;Kim, Yong-Shik
    • Journal of the Korean Solar Energy Society
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    • v.38 no.6
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    • pp.65-72
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    • 2018
  • Since data-driven building technologies have been widely applied to building energy systems, the accuracy of building sensors has more impacts on the building performance and system performance analysis. Various building sensors, however, can have typical errors including a random error (noise) and a systematic error (bias). The systematic error is indicated by the difference between the mean of measurements and their true value. It may occur due to the sensor's physical condition, measured phenomena, working environments inside the systems. Unfortunately, a conventional calibration method has limitations in calibrating the systematic errors because of the difference between working environments and calibration conditions. In such situations, a novel sensor calibration method is needed to handle various sensor errors, especially for systematic errors, in building energy systems having various thermodynamic environments. This study proposes a building sensor calibration method named Virtual In-situ Calibration (VIC) and shows how it is applied into a real building system and how it solves the sensor errors.

Effects of Yoga for Dysmenorrhea Relief: A Systematic Review (월경곤란증에 관한 요가의 효과: 체계적 문헌고찰)

  • Kim, Sang-Dol
    • The Journal of the Korea Contents Association
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    • v.19 no.3
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    • pp.396-404
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    • 2019
  • This study was systematic review to confirm the effects of the yoga on dysmenorrhea. Seven articles were extracted from the CINAHL, the Cochrane library, Embase, PsycINFO, PubMed, and Koreamed electronic databases. Menstrual pain intensity and duration, menstrual distress, QOL, anxiety, anger, and depression levels, homocysteine, TSH, FSH, LH, and prolactin levels were decreased significantly in the yoga group, compared with control group. These findings imply that yoga are a favorable intervention for dysmenorrhea.

Birth cohort effects on maternal and child environmental health: a systematic review (모아의 환경적 건강에 대한 출산 코호트 효과: 체계적 고찰)

  • Chae, JungMi;Kim, Hyun Kyoung
    • Women's Health Nursing
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    • v.27 no.1
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    • pp.27-39
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    • 2021
  • Purpose: This study aimed to review recent findings from birth cohort studies on maternal and child environmental health. Methods: Birth cohort studies regarding environmental health outcomes for mothers and their children were investigated through a systematic review. A literature search was conducted in PubMed, CINAHL, the Cochrane Library, Embase, and RISS to identify published studies using the keywords using a combination of the following keywords: maternal exposure, environmental exposure, health, cohort, and birth cohort. Articles were searched and a quality appraisal using the Newcastle-Ottawa Scale for cohort studies was done. Results: A review of the 14 selected studies revealed that prenatal and early life exposure to environmental pollutants had negative impacts on physical, cognitive, and behavioral development among mothers and children up to 12 years later. Environmental pollutants included endocrine disruptors, air pollution (e.g., particulate matter), and heavy metals. Conclusion: This systematic review demonstrated that exposure to environmental pollutants negatively influences maternal and children's environmental health outcomes from pregnancy to the early years of life. Therefore, maternal health care professionals should take steps to reduce mothers' and children's exposure to environmental pollutants.

The role of percutaneous neurolysis in lumbar disc herniation: systematic review and meta-analysis

  • Manchikanti, Laxmaiah;Knezevic, Emilija;Knezevic, Nebojsa Nick;Sanapati, Mahendra R.;Kaye, Alan D.;Thota, Srinivasa;Hirsch, Joshua A.
    • The Korean Journal of Pain
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    • v.34 no.3
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    • pp.346-368
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    • 2021
  • Background: Recalcitrant disc herniation may result in chronic lumbar radiculopathy or sciatica. Fluoroscopically directed epidural injections and other conservative modalities may provide inadequate improvement in some patients. In these cases, percutaneous neurolysis with targeted delivery of medications is often the next step in pain management. Methods: An evidence-based system of methodologic assessment, namely, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used. Multiple databases were searched from 1966 to January 2021. Principles of the best evidence synthesis were incorporated into qualitative evidence synthesis. The primary outcome measure was the proportion of patients with significant pain relief and functional improvement (≥ 50%). Duration of relief was categorized as short-term (< 6 months) and long-term (≥ 6 months). Results: This assessment identified one high-quality randomized controlled trial (RCT) and 5 moderate-quality non-randomized studies with an application of percutaneous neurolysis in disc herniation. Overall, the results were positive, with level II evidence. Conclusions: Based on the present systematic review, with one RCT and 5 non-randomized studies, the evidence level is II for percutaneous neurolysis in managing lumbar disc herniation.