• 한국재료학회지
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• 제15권1호
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• pp.54-60
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• 2005

Recently a lots of problems have observed in high densified and high integrated electronic components. One of them is ion migration phenomena, which induce the electrical short of electrical circuit. ion migration phenomena has been observed in the field of exposing the specific environment and using for a long tin e. This study was evaluated the generation time of ion migration and was investigated properly test method through water drop test and high temperature high humidity test. Also we observed direct causes and confirmed generation mechanism of dendritic growth as we reproduced the ion migration phenomena. We utilized PCB(printed circuit board) having a comb pattern as follows 0.5, 1.0, 2.0 mm pattern distance. Cu, SnPb and Au were electroplated on the comb pattern. 6.5 V and 15 V were applied in the comb pattern and then we measured the electrical short time causing by ion migration. In these results, we examined a difference of ion migration time depending on pattern materials, applied voltage and pattern spacing of PCB conductor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.439-440
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• 2008

• 한국전문물리치료학회지
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• 제20권2호
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• pp.52-59
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• 2013

The purpose of this study was to determine the reliability and validity of the postural balance program which uses the movement accelerating field principles of posture balance training and evaluation equipment and smartphone movement accelerometer program (SMAP) in healthy young adults. A total of 34 people were appointed as the subject among the healthy young adults. By using Biodex stability system (BSS) and SMAP on the subject, the posture balance capability was evaluated. For the test-retest reliability, SMAP showed the intra-class correlation (ICC: .62~.91) and standard error measurement (SEM: .01~.08). BSS showed the moderate to high reliability of ICC (.88~.93) and SEM (.02~.20). In the reliability of inter-rater, ICC (.59~.73) as to SMAP, showed the reliability of moderate in eyes open stability all (EOSA), eyes open stability anterior posterior (EOSAP), eyes open stability medial lateral (EOSML) and eyes open dinamic all (EODA), eyes open danamic anterior posterior (EODAP), and eyes open danamic medial lateral (EODML). However, ICC showed reliability which was as low as .59 less than in other movements. In addition, BSS showed the reliability of high as ICC (.70~.75). It showed reliability which was as low as ICC (.59 less than) in other movements. In correlation to the balance by attitudes between SMAP and BSS, EOSML (r=.62), EODA (r=.75), EODML (r=.72), ECDAP (r=.64), and ECDML (r=.69) shown differ significantly (p<.05). However, the correlation noted in other movements did not differ significantly. Therefore, SMAP and BSS can be usefully used in the posture balance assessment of the static and dynamic condition with eyes opened and closed.

• 한국전문물리치료학회지
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• 제26권1호
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• pp.8-18
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• 2019

Background: Numerous studies have used smartphone applications to measure the range of motion in different joints. In addition, studies measuring the active range of motion (AROM) of the craniocervical joint have revealed high reliability. However, the subjects in these studies were all healthy subjects. No study has yet been conducted to measure the inter-rater reliability for the AROM of the craniocervical joint in stroke patients. Objects: The purpose of this study was to investigate the inter-rater reliability of the AROM of the craniocervical joint using a smartphone. Methods: The participants included 21 subjects who had strokes (17 males and 4 females). Two raters evaluated six types of craniocervical AROM, including flexion, extension, lateral flexion to the hemiplegic side, lateral flexion to the non-hemiplegic side, rotation to the hemiplegic side, and rotation to the non-hemiplegic side, using a goniometer and a smartphone to investigate inter-rater reliability. The inter-rater reliability was analyzed by intraclass correlation coefficients (ICC). Results: The inter-rater reliability of the smartphone was good for extension, lateral flexion to the hemiplegic side, lateral flexion to the non-hemiplegic side, and rotation to the hemiplegic side [ICC(2,k)=.86~.88] and excellent for flexion [ICC(2,k)=.95]. The inter-rater reliability for rotation to the non-hemiplegic side was moderate [ICC(2,k)=.72]. Conclusion: These results suggest that the smartphone offers high inter-rater reliability for measurements of the craniocervical AROM in patients with stroke.

• 동력기계공학회지
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• 제16권3호
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• pp.44-50
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• 2012

The reliability qualification test is essential in order to ensure the life time of the product under the normal operation conditions when a new product is developed. The reliability qualification test period has an important impact on the development time of new product. Therefore, some researches to reduce the test time of reliability qualification test have been actively studied. Generally, accelerated life test is well known as one method that can save the test time of the reliability qualification test. This test is conducted under the higher stress condition than normal condition. So we need to investigate what factor affects to the higher stress condition. This paper shows the relationship between the acceleration factor and reliability qualification test period. Especially, we focused on the method to obtain effective acceleration factors under the high temperature condition. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• The Journal of Korean Physical Therapy
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• 제19권5호
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• pp.29-41
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• 2007

Purpose: The aim of this study was to examine the validity and reliability on Psychometric Arthritis Impact Measurement Scale-Short Form (AIMS-SF) in patients with knee osteoarthritis(OA). Methods: The sample consisted of 62 patients who had received physical therapy at the physical therapy units of the Andong Medical Center, Sungso Hospital, Ahn Orthopedic Surgery Clinic, and St. Luke Clinic in Andong city in June 2006. Questionnaire on the AIMS-SF was recruited by 5 physical therapists. The internal structure and reliability of the scales were evaluated by means of item-internal consistency(Cronbach's alpha coefficient: ${\alpha}$), item-discriminant validity, Pearson's relation coefficient. To explore construct validity we conducted a principal component factor analysis with varimax rotation analysis. The criterion for factor extraction was an eigenvalue >1.0. Results: 62 OA patients's an average $age{\pm}standard$ deviation was $53.8{\pm}14.4$ years (range: $40{\sim}81$ yr). The internal consistency reliability of 11 items, as estimated by Cronbach's ${\alpha}$ coefficient, was high ranging $0.60{\sim}0.78$ (except for 0.40 for mobility level and -0.48 for mood). The internal consistency reliability of item-each scale was also high $0.82{\sim}0.93$ (except for 0.48 for mood). Of 11 items, the item-discriminant validity on 6 items was high (${\alpha}$ coefficient range: $0.11{\sim}0.25$), however, others (0.57 for tension level, 0.48 for arthritis pain, 0.41 for walking and bending, and 0.40 for work) were a little low. The construct validity by factor analysis was a little low. Conclusion: In conclusion, the results reported here confirm the validity and reliability of the AIMS-SF in patients with OA of the knee. The Collection of information on health status using this instrument was acceptable to patients. A further prospective multi-center study will be necessary to prove the construct validity.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1132-1137
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• 2011

Critical systems with high reliability feature fault tolerant redundancy. Conventional analytical reliability analysis methods that use the Reliability Block Diagram do not adequately reflect characteristics of the redundancy management system and are not suitable for this applications. This paper uses Monte-Carlo method to calculate the reliability of complicated redundant systems. The method was first validated for cases with analytical solutions. Then, the tool was successfully applied to analyze reliability of the flight control systems with a voter as redundancy management system.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2001년도 정기학술대회
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• pp.91-97
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• 2001

These Study are for the development of the reliability assessment test code and test equipment and test procedures of the heavy sluice gate hydraulic cylinder. Because there is no reliability test code for the heavy sluice gate hydraulic cylinder inside and outside of the country, the modified reliability test code is made reference for the related existing standards like as ISO, JIS, MIL, TUV, DIN, KS and etc. In this study, the novel method is proposed to evaluate efficiency of the heavy sluice gate hydraulic cylinder on the loading conditions and established the conditions of the acceleration life test to reduce the testing time and cycles. The testing equipments for life test, lode operating test, high and low temperature test and salt spray test have been established for 8 month, and the reliability tests are accomplished. The test results of the heavy sluice gate hydraulic cylinder which is produced and tested initially in Korea are satisfied the durability life cycle on the using conditions.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.195-200
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• 1993

This paper develops practical and realistic reliability models and methods for the evalusion of system reliability and system reliability-based rating of R.C box-girder bridge superstructures. The precise prediction of reserved carrying capacity of bridge as a system is extremely difficult expecially when the bridges are highly redundant and significantly deteriorated or damaged. This paper proposes a new approach for the evaluation of reserved system carrying capacity of bridges in terms of equivalent system-strength, which may be defined as a bridge system-strength corresponding to the system reliability of the bridge. This can be derived from an inverse process based on the concept of FOSM form of system reliability index. The strength limit state models for R.C box-girder bridges suggested in the paper are based on the basic bending and shear strength. and the system reliability problem of box-girder superstructure is formulated as parallel-series models obtained from the FMA(Failure Mode Approach) based on major failure mechanism or critical failure states of each girder. AFOSM and IST(Importance Sampling Technique) simulation algorithm is used for the reliability analysis of the proposed models.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.206-210
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• 2007

IEC 62278 presents a process to implement a consistent approach to the management of reliability for railway applications. A reliability program has to be established at the outset of a project in order to manage reliability activities effectively through the life cycle. The first step of the reliability program is to evaluate reliability requirements and targets based on the system specifications. The system specifications are derived from the customer's needs. The way in which the system requirements reflect the customer's needs is strongly dependent on the characteristics of the product. In general the customer of commercial trains presents the system requirements from their needs. However, the relation between the customer and supplier is equivocal for a project to development a prototype train, and the reliability program should be different from that of an usual commercial project. This paper deals with a process to manage reliability activities for the development of a protype train based on the experiences obtained from the development of the Korea High-Speed Train: Hanvit-350.