• 제목/요약/키워드: case - control study

검색결과 6,341건 처리시간 0.043초

전등 부하 및 전동기 부하시 전기화재예방 제어장치의 동작 특성에 관한 연구 (A Study on Dynamic Characteristics of Electrical Fire Prevention Control Devices with a lamp and a motor load)

  • 이상호;오홍석
    • 한국산업융합학회 논문집
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    • 제5권3호
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    • pp.255-260
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    • 2002
  • Recently, the occurrences of electrical fire have been suppressed by an earth leakage breaker(ELB), a no fuse breaker(NFB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the ELB to break the circuit in the case of the failure of pressure contacts on connecting points and the momentary short circuit. Therefore, it is require to study the constructive problem of the ELB. In this paper, we have developed the auxiliary control device, electrical fire prevention control device(EFPCD), of the ELB. And we have tested the operation characteristics of the ELB according to the load(R, L) As a result of this experiment, we could prevent the electrical fire due to the spark and the overheat occurring in the failure of pressure contacts on connecting points and the momentary short circuit.

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자동차 PCSV (Purge Control Solenoid Valve) 제조공정의 누적수율 개선을 위한 6시그마 적용연구 (A Six Sigma Application Case Study to Improve a Rolled Throughput Yield of an Automobile PCSV(Purge Control Solenoid Valve))

  • 양성남;노성호;서종현
    • 대한안전경영과학회지
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    • 제14권1호
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    • pp.179-187
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    • 2012
  • This paper presents a six sigma application case study for an automobile PCSV manufacturing process using rolled throughput yield improvement activity. Hidden factor and first yield concept is introduced and DMAIC procedure is implemented to maximize the first pass yield. The result of the six sigma project amounts to the reduction of failure cost of 0.1 billion won per year in the PCSV manufacturing process. This paper can benefit six sigma practitioners in some ways.

Preliminary Investigation of Association between Methylphenidate and Serum Growth Markers in Children with Attention-Deficit/Hyperactivity Disorder: A Cross-Sectional Case-Control Study

  • Kim, Woo Jin;Bang, Young Rong;Kang, Je-Wook;Yoo, Jae Ho;Kim, Seong Hwan;Park, Jae Hong
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • 제31권3호
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    • pp.154-160
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    • 2020
  • Objectives: It remains unclear whether methylphenidate (MPH) has yadverse effects on growth in children. This study aimed to investigate the association of MPH with serum biological markers of growth in children with attention-deficit/hyperactivity disorder (ADHD). Methods: The present study included 103 children with ADHD (64 drug-naive children, 39 MPH-treated children) and 112 control subjects. Children with ADHD were diagnosed on the basis of a semi-structured interview. Levels of biochemical markers of growth, including insulin-like growth factor-I, thyroid stimulating hormone (TSH), free T4, calcium, phosphorus, alkaline phosphatase, vitamin D, hemoglobin, total protein, albumin, total cholesterol, and hematocrit were measured in these individuals. Results: Except in case of TSH, no intergroup differences were found in the levels of the growth markers. The levels of TSH were found to be lower in the MPH-treated boys with ADHD than in the drug-naive and control groups (p<0.05), although the levels of TSH in all the groups were within normal limits. Conclusion: In this cross-sectional study, no significant association was found between MPH and growth markers. This calls for the need to carry out prospective longitudinal research studies in the future that investigate the effect of MPH on the growth trajectory in children.

과반수 미만 의결권 보유시 지배력 판단 사례: 힘의 보유 여부 판단을 위한 단계별 검토 (A Case of Determining Control when Holding Voting Rights of Less Than a Majority: A Step-by-step Review to Determine whether the Power is Retained)

  • 김지영;오명전
    • 아태비즈니스연구
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    • 제14권1호
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    • pp.313-325
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    • 2023
  • Purpose - The purpose of this study is to examine the process of determining control in a situation where investors hold less than a majority of the voting rights of the investee through case. Design/methodology/approach - In this study, the various and complex considerations presented in K-IFRS 1110 'Consolidated Financial Statements' were systematically classified and stratified. Findings - First, the agreement to delegate voting rights does not necessarily have to be documented, but it can be said to be substantive rights right only if it is not of the nature that one party can discontinue at any time. Second, if it is clear that investors do not have power due to the relative size of voting rights and the degree of stock dispersion, there is no need to review the past shareholders' meeting resolutions and additional facts and circumstances. Research implications or Originality - This study expects to minimize errors in applying the standards by classifying and stratifying the various considerations presented in K-IFRS 1110 into first and subsequent considerations. In addition, it is expected to contribute to reducing practical confusion in determining control by presenting a step-by-step review through case on whether or not to have power to judge control when holding voting rights of less than a majority.

2급 및 3급 치근이개부 병변에서 합성골이식의 효과에 대한 임상적 및 방사선학적 연구 (A CLINICAL AND RADIOLOGICAL STUDY ON THE EFFECT OF SYNTHETIC BONE IN CLASS II AND III FURACATION INVOLVEMENTS)

  • 염규선;김병옥;한경윤
    • Journal of Periodontal and Implant Science
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    • 제23권3호
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    • pp.475-492
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    • 1993
  • The effect of synthetic bone materials was assessed in the patients with pure periodontal class II and III furcation defects. The buccal aspects of the maxillary and mandilular first and second molars were surgically exposed, and synthetic bone materials were interposed between the gingival flap and the furcation defects in the experimental group. The control group were treated without the use of synthetic bone materials by same operator. Probing pocket depth, gingival recession, and loss of attachment, were measured by Michigan O-probe and tooth mobility was evaluated by an electronic mobility tester(Periotest(R), Siemens co. Germany) at preoperation and 3-, 6-, and 12-month postoperation. Standardized radiogrphs were taken at preoperation and 6-month and 12-month postoperation. The postoperative change of clinical parameters and the difference between experimental group and control group were statistically analyzed by Student, t-test. The results were as follows: 1. The probing pocket depth at the 3-, 6-, and 12-month postoperative examination was significantly decreased, compared to that at preoperative examination in both experimental group and control group(P<0.005), but there was no significantly difference between experimental group and control group. 2. The amount of gingival recession at the 3-, 6-, and 12-month postoperative examination was increased, compared to that at the preoperative examination in both experimental and control group(P<0.005). In the case of the class III furcation involvement, the amount of gingival recession at the 3-, 6-, and 12-month postoperative examination was more significantly increased in control group than experimental group(P<0.05). 3. The amount of loss of attachment at the 3-, 6-, and 12-month postoperative examination was significantly decreased, compared to that at the preoperative examination in both experimental and control group in the case of class II furcation involvement, and in experimental group only in the case of furcation III involvement(P<0.005). The amount of loss of attachment at, the 3-, 6-, and 12-month postoperative examination was more significantly decreased in experimental group than control group in the case of the class III furcation involvement(P<0.05), but in the case of class II furcation involvement there was no significant difference between experimental group and control group. 4. The tooth mobility at the 3-, 6-, and 12-month postoperative examination was significantly decreased, compared to that at the preoperative examination in both experimental and control group(P<0.005), but there was no significant difference between experimental group and control group. 5. Radiopacity of furcation area was greatly increased in the experiment group, but there was no radiographic change in the control group.

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철도시스템의 안전운영 검증을 위한 Safety Case 사례연구 (A Case Study on Safety Case for the Verification of Railway Safety)

  • 곽상록;김상암;왕종배;조연옥
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.618-622
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    • 2005
  • Railway safety case is an important measure for demonstrates operating company's capability, commitment and competence in accordance with Railway Regulation 2000 in UK. Safety case describes the scope of operation, definition and boundary of activity, risk analysis, system safety activity, annul safety plan. Relationships between' these components and company's policy, organization, human resource, control measure, investment plan are also included. A case study for Network Rail (infrastructure manager)'s safety case is described in this paper for the construction of safety rule and safety planning.

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Performance evaluation of inerter-based damping devices for structural vibration control of stay cables

  • Huang, Zhiwen;Hua, Xugang;Chen, Zhengqing;Niu, Huawei
    • Smart Structures and Systems
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    • 제23권6호
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    • pp.615-626
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    • 2019
  • Inerter-based damping devices (IBBDs), which consist of inerter, spring and viscous damper, have been extensively investigated in vehicle suspension systems and demonstrated to be more effective than the traditional control devices with spring and viscous damper only. In the present study, the control performance on cable vibration reduction was studied for four different inerter-based damping devices, namely the parallel-connected viscous mass damper (PVMD), series-connected viscous mass damper (SVMD), tuned inerter dampers (TID) and tuned viscous mass damper (TVMD). Firstly the mechanism of the ball screw inerter is introduced. Then the state-space formulation of the cable-TID system is derived as an example for the cable-IBBDs system. Based on the complex modal analysis, single-mode cable vibration control analysis is conducted for PVMD, SVMD, TID and TVMD, and their optimal parameters and the maximum attainable damping ratios of the cable/damper system are obtained for several specified damper locations and modes in combination by the Nelder-Mead simplex algorithm. Lastly, optimal design of PVMD is developed for multi-mode vibration control of cable, and the results of damping ratio analysis are validated through the forced vibration analysis in a case study by numerical simulation. The results show that all the four inerter-based damping devices significantly outperform the viscous damper for single-mode vibration control. In the case of multi-mode vibration control, PVMD can provide more damping to the first four modes of cable than the viscous damper does, and their maximum control forces under resonant frequency of harmonic forced vibration are nearly the same. The results of this study clearly demonstrate the effectiveness and advantages of PVMD in cable vibration control.

만성치주염 환자에 대한 저용량 독시싸이클린의 임상적 효과 (Clinical Effect of the Subantimicrobial Dose of Doxycycline ( SDD ) on the Chronic Periodontitis)

  • 김윤식;백정원;김창성;최성호;김종관
    • Journal of Periodontal and Implant Science
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    • 제32권2호
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    • pp.415-428
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    • 2002
  • Periodontal disease is a complex infectious disease caused by bacteria in the oral mucosa, which results in gingival inflammation, breakdown of periodontal tissues, bone resorption, and finally tooth loss. Mechanical plaque control methods-scaling and root planing are effective methods to stop the progression of such periodontal disease. It was reported that subantimicrobial dose of doxycycline(SDD) regimen could improve clinical conditions of periodontal tissues without causing the overgrowth of opportunistic organisms that was a typical antibiotic side effect. Therefore pharmacological therapy, used in conjunction with mechanical therapy could be considered a useful treatment modality in the treatment of chronic periodontal disease. In this study, 30 patients diagnosed as moderate to advanced chronic periodontitis were divided into 2 groups. In this double-blind, placebo-controlled study, the patients were administered 20mg doxycycline capsule or placebo capsule b.i.d. for 4months, after scaling and root planing. Clinical parameters-bleeding on probing, pocket depth and clinical attachment level were compared and evaluated between these groups at periods of first visit, 1 month, 2 months, 3 months, 4 months. The results were as follows ; 1. In case of moderate periodontitis, pocket depth showed significant reduction after treatment in both the control & experiment groups, when compared with the baseline values(p<0.01), but in case of advanced periodontitis, only the experiment group showed significant reduction after treatment when compared with the baseline values(p<0.05). Statistically significant reduction in pocket depth was observed in the experiment group compared to the control group(p<0.05). 2. In case of moderate periodontitis, clinical attachment level showed significant reduction after treatment in both the control & experiment groups, when compared with the baseline values(p<0.01), but in case of advanced periodontitis, only the experiment group showed significant reduction after treatment when compared with the baseline values(p<0.05). Statistically significant reduction in clinical attachment level was observed in the experiment group compared to the control group(p<0.05). 3. Bleeding on probing improved after treatment in both the groups. In case of moderate periodontitis, the experiment group showed statistically significant reduction of bleeding on probing when compared with the control group at 1 and 4 months after treatment(p<0.05). In case of advanced periodontitis, treatment resulted in statistically significant reduction of bleeding on probing in both the groups(p<0.05). These results indicate that the use of subantimicrobial dose of doxycycline is a useful supplement to mechanical treatment for periodontal patients in ameliorating the clinical parameters such as periodontal pocket, attachment level, and bleeding on probing.

중소기업의 효율적 데이터 품질관리를 위한 스크럼 기반 표준관리 방안 : 'I'사 물류서비스 적용 사례 (Investigation on the Scrum-based Standard Management for Efficient Data Quality Control of Small-sized Companies : A Case Study on Distribution Service of Company 'I')

  • 김태윤;김남규;손용락
    • Journal of Information Technology Applications and Management
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    • 제17권1호
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    • pp.83-105
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    • 2010
  • The competence of enterprise for managing information is evaluated not by the amount of information but by the quality of information such as response time, data consistency, and data correctness. The degradation of data quality is usually caused by the inappropriate process of managing the structure and value of stored data. According to the recent survey on the actual condition of data quality management, the correctness and consistency of data appeared to be the most problematic area among the six criteria of data quality management such as correctness, consistency, availability, timeliness, accessibility, and security. Moreover, the problem was more serious in case of small and medium-sized companies than large enterprises. In this paper, therefore, we attempt to propose a new data quality control methodology for small and medium-sized companies that can improve the correctness and consistency of data without consuming too much time and cost. To adopt the proposed methodology to real application immediately, we provided some scripts for as-is analysis and devised automation tools for managing naming rules of vocabulary, terminology, and data code. Additionally, we performed case study on the distribution service of a small-sized company to estimate the applicability of our tool and methodology.

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산후 유방 마사지 손기술에 대한 다중사례분석 (Multiple-Case Studies of Hand-on Breast Massage Techniques used by Breastfeeding Experts)

  • 박현순;조인숙;김민경
    • 여성건강간호학회지
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    • 제23권3호
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    • pp.155-165
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    • 2017
  • Purpose: The aim of this study was to understand the hand-on breast massage techniques used by well-known experts in breastfeeding clinics. Methods: A qualitative multiple-case design was applied that involved a feasibility test. Four experts sampling qualitative data collected by observing participants and in individual interviews were analyzed by content analysis, linking data to the propositions, and cross-case pattern matching. This study explored differences within and between cases, and the possibilities of replicating findings across cases. Thirty-nine postpartum women participated voluntarily in the feasibility test, which investigated the usability of four massage techniques. Results: The four techniques showed considerable similarities in terms of the application of stimulation to the breast base and increased flexibility of the wired flexible body, which was the core mechanism underlying the techniques. The breast management strategies were consistent with existing practice guidelines with the exception of using cold cabbage to control engorgement pain. There was insufficient scientific evidence for supporting the massage techniques used by the experts. All of the techniques showed 100% education completeness, but application rates were higher for self-control-oriented techniques. Conclusion: The massage techniques applied by experts in breastfeeding were based on hypotheses and self-control techniques are feasible to apply in practice.