• Title/Summary/Keyword: Fail-safe

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A Meta-Analysis of the Effects of the Career Education Program for Students with Disabilities (장애 학생을 대상으로 한 진로교육 프로그램의 효과에 관한 메타분석)

  • Choi, Hea Young
    • Human Ecology Research
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    • v.55 no.3
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    • pp.289-301
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    • 2017
  • This study was to analyze the effects of the career education program for students with disabilities. The analysis was performed based on two research questions. First, the total effect size on the career program for students with disabilities was considered. Second, the difference of the effect size between the sub-groups regarding dependency variables, types of disabilities, types of schools, number of people, and number of sessions was also included for analysis. For this, the author reviewed a database and analyzed 12 previous studies, presented in five master thesis and seven Korean journals from 2005 to 2015 based on the author's selection criteria. Subsequently, 27 effect size was found. The publication bias was analyzed by Rosenthal's fail-safe N. The overall effect size for all studies on the random effect model was 1.717, which was positive and high in value. Given the heterogeneity among the effect size, the subgroup analysis was conducted, and indicated that the effect size was significantly high when the purpose of the program was related to the student's self-decision ability. The results demonstrated that the programs were specified for students with intellectual disabilities, when the schools were elementary, when the number of students in a group was 1-10, and when program sessions lasted more than 21 times, the effect size was high. Implication for the future research and program implication were discussed on these findings.

Modeling of EMB (Electro Mechanical Brake) to Emulate Gearbox Fault and Control (기어의 고장을 구현하기 위한 EMB(Electro Mechanical Brake) 모델링 및 제어)

  • Choe, Byung-Do;Hwang, Woo-Hyun;Huh, Kun-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.6
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    • pp.33-38
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    • 2012
  • EMB is considered as the next generation braking mechanism because it has simple structure and is environment friendly. However, as other brake mechanisms, EMB should be operated reliably for any operating conditions. EMB should be designed with fail-safe and fault-tolerant control concepts which require robust fault detection algorithms for various possible faults. In the design of fault detection algorithms, it is very difficult to construct faulty conditions in real EMB and thus, simulations are often used to emulate the faulty conditions. In this paper, a simulation tool is developed using the commercial software to emulate gear faults in the EMB mechanism. A backlash compensation algorithm is introduced based on contact point detection because screw backlash causes a delay in clamping force response time.

A Study on the Standard Working Area by Somatometria (인체계측(人體計測)에 의(依)한 표준작업역(標準作業域)의 연구(硏究))

  • Lee, Sang-Do;Jeong, Jung-Hui
    • Journal of Korean Institute of Industrial Engineers
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    • v.2 no.1
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    • pp.61-78
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    • 1976
  • The purpose of this study is to establish the horizontal and vertical working area which is dependent on measuring value of workers, body in order to make easy and stable working environments, and then to design the size of machines, tools and instruments in production factory because of making the practical production conditions which is the most suitable to human characteristics. But there is necessity that we have to review numeric value of measurement periodically because the size of workers' body is variable according to periodic and social circumstances. The establishment of standard working area after measurement enable us to make the best working conditions and we can design standard working table, optimum size of all machines and tools in production activity. Therefore, we can also acknowledge the importance of studying on human engineering because human engineering is necessary to reduction of fatigue in working, saving workers from industrial accidents, fail-safe system, improvement of productivity with increase in efficiency and etc. Finally, this study informs us that numeric value of measurement is larger than that of Japan, but not than that of America and Germany. So we can establish standard working area which is the most suitable for Korean inherence after measurement of detailed parts for workers' body.

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The Effect of Patient Education Interventions on Distress, Self-Care Knowledge and Self-Care Behavior of Oncology Patients: A Meta-Analysis (암환자교육이 암환자의 심리적 디스트레스와 자가간호지식 및 자가간호행위에 미치는 효과: 메타분석)

  • Oh, Pok-Ja;Choi, Hyeong-Ji
    • Asian Oncology Nursing
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    • v.12 no.4
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    • pp.257-266
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    • 2012
  • Purpose: The purpose of this study was to evaluate the effectiveness of patient education interventions on distress, self-care knowledge and self-care behavior in cancer patients. Methods: A total of 1,102 studies were retrieved from 6 electronic databases in Korea. From these studies, 18 studies met the inclusion criteria with a total of 850 participants. Two authors independently assessed the methodological quality by Cochrane's Risk of Bias and Methodological Items for Non Randomized Studies. The data were analyzed by the RevMan 5.1 program of Cochrane library. Results: Overall effect size of education interventions on anxiety was -2.12 (95% CI:-3.90, -0.34) (p<.001). The effects on self-care knowledge and self care behavior were -1.08 (95% CI:-1.73, -0.43) (p=.001), and -1.41 (95% CI:-2.13, -0.68) (p<.001), respectively. Publication bias was detected as evaluated by funnel plot, but the fail-safe number was moderate. Conclusion: This study suggests that patient education interventions can relieve anxiety and self-care. Further randomized controlled trials studies are needed to evaluate the effects of patient education intervention on depression.

Pharmacotherapy for Obesity in Mood Disorders (기분장애 환자의 비만에 대한 약물치료)

  • Sohn, Inki;Lee, Kyu-Hang
    • Korean Journal of Psychosomatic Medicine
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    • v.22 no.2
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    • pp.63-70
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    • 2014
  • The prevalence of obesity and overweight is increasing in mood disorder, and it is connected to an increased cardiovascular mortality. Because of them, treatment for obesity may be an essential part of mood disorder treatment. Similar to the general population, non-pharmacological treatment such as correction of life habits should be considered first of all. If this approaches are fail, pharmacological treatment for obesity would be required as next step. Any drug for obesity is not approved officially in mood disorder. So approved drugs in general population, and drugs supported by several studies are prescribed in clinical settings. Several treatment guidelines for mood disorder and studies support that orlistat, metformin, topiramate and bupropion is effective and safe.

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HFAT: Log-Based FAT File System Using Dynamic Allocation Method

  • Kim, Nam Ho;Yu, Yun Seop
    • Journal of information and communication convergence engineering
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    • v.10 no.4
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    • pp.405-410
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    • 2012
  • Several attempts have been made to add journaling capability to a traditional file allocation table (FAT) file system. However, they encountered issues such as excessive system load or instability of the journaling data itself. If journaling data is saved as a file format, it can be corrupted by a user application. However, if journaling data is saved in a fixed area such as a reserved area, the storage can be physically corrupted because of excessive system load. To solve this problem, a new method that dynamically allocates journaling data is introduced. In this method, the journaling data is not saved as a file format. Using a reserved area and reserved FAT status entry of the FAT file system specification, the journaling data can be dynamically allocated and cannot be accessed by user applications. The experimental results show that this method is more stable and scalable than other log-based FAT file systems. HFAT was tested with more than 12,000 power failures and was stable.

A Study on the Power System Application of High-Tc Superconducting Fault Current Limiter (고온초전도 한류기의 전력계통 적용에 관한 연구)

  • Bae, Hyeong-Thaek;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 2006.07a
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    • pp.115-116
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    • 2006
  • Since the discovery of the high-temperature superconductors, many researches have been performed for the practical applications of superconductivity technologies in various fields. As results, significant progress has been achieved. Especially, Superconducting Fault Current Limiter (SFCL) offers an attractive means to limit fault current in power systems. The SFCLS, in contrast to current limiting reactors or high impedance transformers, are capable of limiting short circuit currents without adding considerable voltage drop and energy loss to power systems during normal operation. Under fault conditions, a resistance is automatically inserted into the power grid to limit the peak short-circuit current by transition from the superconducting state to the normal state, the quench. The advantages, like fail safe operation and quick recovery, make SFCL very attractive, especially for rapidly growing power systems with higher short-circuit capacities. In order to verify the effectiveness of the SFCL, in this paper, the analysis of fault current and voltage stability assessment in a sample distribution system and a transmission system are performed by the PSCAD/EMTDC based simulation method. Through the simulation, the advantage of SFCL application is shown, and the effective parameters of the SFCL are also recommended for both distribution and transmission systems. A resistive type component of SFCL is adopted in the analysis. The simulation results demonstrate not only the effectiveness of the proposed simulation scheme but also SFCL parameter assessment technique.

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Case Study of Intermittent Poor Acceleration Fault Diagnosis by Brake Switch Fault (브레이크 스위치 결함에 의한 간헐적인 가속불량 현상의 고장진단 사례연구)

  • Kim, Sung Mo;Jo, Haeng Deug
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.2
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    • pp.203-210
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    • 2015
  • This paper investigates the failure of a car with a 2.5-liter CRDi engine of the Hyundai Company. The failure is caused by intermittent poor acceleration while driving. To analyze the cause, we investigated the air intake volume, the fuel injection, and the air-fuel ratio, which were determined to be normal. The brake switch signal error was discovered while analyzing the function that limits the output of the engine. While investigating the cause, we discovered the corrosion of the pins on the connector of the brake switch. We determined that it was generated by soapy water flowing in the solar film. Therefore, the cause of the failure was the brake switch signal errors. Additionally, we determined that ECM was the normal fail-safe mode that implemented the override device for safety during normal acceleration. Based on these results, further solar film experiments must be conducted to fully elucidate the causes.

A Study on Design of the Trip Computer for ECC System Based on Dynamic Safety System

  • Kim, Seog-Nam;Seong, Poong-Hyun
    • Nuclear Engineering and Technology
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    • v.32 no.4
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    • pp.316-327
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    • 2000
  • The Emergency Core Cooling System in current nuclear power plants typically has a considerable number of complex functions and largely cumbersome operator interfaces. Functions for initiation, switch-over between various phases of operation, interlocks, monitoring, and alarming are usually performed by relays and analog comparator logic which are difficult to maintain and test. To improve problems of an analog based ECC (Emergency Core Cooling) System, the trip computer for ECCS based on Dynamic Safety System (DSS) is implemented. The DSS is a computer based reactor protection system that has fail-safe nature and performs a dynamic self-testing. The most important feature of the DSS is the introduction of test signal that send the system into a tripped state. The test signals are interleaved with the plant signals to produce an output which switches between a tripped and health state. The dynamic operation is a key feature of the failsafe design of the system. In this work, a possible implementation of the DSS using PLC is presented for a CANDU Reactor. ECC System of the CANDU Reactor is selected as the reference system.

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Meta-Analysis of the Research Findings Concerning Functional Relationships of Explanatory Variables to Hope (희망과 설명 요인과의 함수적 관계에 대한 메타 분석)

  • 김달숙;문원희;안성윤;오현숙;권경희;박문경;최현숙;이미옥;김영주
    • Journal of Korean Academy of Nursing
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    • v.34 no.5
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    • pp.673-684
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    • 2004
  • Purpose: The purpose of the study was to meta-analyze the relationships of major concepts, which were made by synthesizing similar explanatory variables into more comprehensive concepts, to hope. Method: The relevant researches from Jan 1980 to Dec 2003, performed in adults or adult patients, were collected. Using the SAS program, meta-analysis were done with the input data of the number of subjects, the correlation coefficients provided from most of the studies or a few transformed correlation coefficients from F value. In order to get the analysis to be done in homogeneous status of the data regarding each relationship of each major concept to hope(p> 0.05), heterogeneous data were eliminated in repeating Q-test. Result: The major variable regarding relationship to self/transcendental being/life(spiritual wellbeing & self esteem) and social support(social support & family support) have very large positive effects on hope(D=l.72, D=l.27). The negative effect of the variable regarding captive state(uncertainty in illness, perceived unhealthiness status, & fatigue) and positive effect of coping(approach coping) on hope are in the level between moderate to large(D=-0.61, D=0.78). All the effects of the major concepts on hope were verified as significant statistically(p=.000). The Fail -Safe numbers showed the significant effects of the three major concepts except coping on hope were reliable. Conclusion: The results can be a guide to advance hope theory for nursing.