• Title/Summary/Keyword: Reliability analyses

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A Study on the Effects of KORAIL's CSR on Customers' Reliability and Loyalty (철도공사의 사회적 책임이 고객신뢰와 충성도에 미치는 영향에 관한 연구)

  • Yang, Jae-Hoon
    • Journal of the Korean Society for Railway
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    • v.17 no.6
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    • pp.423-432
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    • 2014
  • The purchasing behavior of consumers is related to service quality and corporate social responsibility (CSR). Therefore, CSR is recognized as an important factor in company strategies. This study determines the relationship between the CSR activities of KORAIL and the reuse intention and recommendation intention of the consumer. CSR is composed of economic, legal, philanthropic, ethical, and environmental responsibilities. In the results of the structural equation modeling analyses, legal responsibility and economic reliability affect the reliability of KORAIL and this reliability affects the customers' reliability and loyalty. This paper proposes a compliance program, wagon safety information, customized tour packages, and communication strategy that will increase customer's reliability and loyalty.

An Application of Software Reliability Estimation Model on Weapon System (국내 무기체계 분야의 소프트웨어 신뢰성 추정 모델 적용 사례)

  • Bak, Da-Un
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.178-186
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    • 2020
  • In the domain of Korean weapon system development, issues about software reliability have become crucial factors when developing a weapon system. There is a process required for weapon system software development and management that includes certain activities required to improve the reliability of software. However, these activities are biased toward static and dynamic analyses of source code and do not include activities necessarily required by the international standard. IEEE std. 1633-2016 defines a process for software reliability engineering and describes software reliability estimation as an essential activity in the process. Software reliability estimation means that collecting defective data during the test and estimating software reliability by using the statistical model. Based on the estimated model, developers could estimate the failure rate and make comparisons with the objective failure rate to determine termination of the test. In this study, we collected defective data and applied reliability estimation models to analyze software reliability in the development of a weapon system. To achieve objective software reliability, we continuously tested our software and quantitatively calculated software reliability. Through the research, we hope that efforts to include activities described by the international standard will be carried out in the domain of Korean weapon system development.

Reliability and Validity of the Quality of Life-Family Version (QOL-FV) in Turkish Family Caregivers of Patients with Cancer

  • Okcin, Figen;Karadakovan, Ayfer
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.9
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    • pp.4235-4240
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    • 2012
  • Objectives: Family caregivers (FCs) are often the primary source of social and emotional support for cancer patients and play a major role in how well they manage their illness. The aim of this study was to create an Turkish version of the Quality of Life - Family Version (QOL-FV) and to evaluate its psychometric properties in a sample of FCs of cancer patients. Materials and Methods: This study was carried out with the FCs of 218 patients with cancer. Data were collected with a Demographic Questionnaire and the QOL-FV and The Multidimentional Scale of Perceived Social Support (MSPSS). The QOL-FV was developed by Ferrell and Grant and is composed of 4 subdimensions. Linguistic validity, translation, back translation, and content validity were tested with expert opinions. Test-retest reliability, and internal consistency reliability were assessed. Construct validity was tested by factor analysis and with the scale of the MSPSS. Results: The family caregivers were between the ages of 46-56 (32.6%), a great number of them being male (52.8%). The scale is made up of four subdimensions. The result of the test-retest analysis of this scale was calculated as r:0.86. As a result of the reliability analysis, six items were eliminated from the scale, factor analyses were fulfilled according to varimax transformation through the method of principal components. Four new subdimensions were restrustured at the end of the analysis. The scale of Cronbach ${\alpha}$ coefficient was calculated as 0.90. Concurrent validity showed low correlations with the MSPSS (r=0.29). Conclusions: The QOL-FV, adapted into Turkish, was found to have sufficient reliability and validity.

Reliability of Exterior Orientation in Bundle Adjustment for SPOT Imagery (SPOT 영상을 위한 번들조성에서 외부표정의 신뢰성)

  • Park, Hong Gi
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.1
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    • pp.151-158
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    • 1992
  • Topographic mapping from economic SPOT stereo imagery than aerial photographs has become possible. Many of authors have studied the possibility of base map revisions and the accuracy of results. They have concluded that the SPOT image is suitable for 1/50,000 to 1/100,000 topographic map. For topographic map, orthophoto and DTM generation from SPOT imagery, accurate exterior orientation parameters are needed. But since the geometric characteristic of SPOT image is dynamic linear array imagery, the conventional bundle adjustment for photogrammetry can not be directly applied. Reliability is the ability to detect gross error, which is called the internal reliability, and the effect of non-detectable gross error on the results of exterior orientation, which is called the external reliability. This paper shows how the reliability of SPOT imagery depends on the different coordinate systems, presentations of coordinate for flight direction, orders of exterior orientation parameters and distribution of control points, and thus analyses the theoretical reliability of the exterior orientation, which can provide a basis for the planning of SPOT projects.

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A Study on the Development of Web-based Preventive Maintenance System for the Driverless Rubber-Tired K-AGT (한국형 무인운전 고무차륜 AGT 시스템의 유지보수를 위한 신뢰성 기반의 고장 예방정비 시스템 개발에 관한 연구)

  • Son, Young-Tak;Chun, Hwan-Kyu;Uhm, Ho-Young;Lee, Ho-Yong;Han, Seok-Youn;Suh, Myung-Won
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.5
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    • pp.36-47
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    • 2010
  • The Korean Railroad Research Institute (KRRI) has developed the rubber tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based Preventive Maintenance (PM) system for the KAGT train system. The framework of the PM system is based on performing a reliability analysis and a failure mode effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high in the list for performing the overall maintenance plans. Through registration of historical failure data, the reliability indexes can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational life times and failure rates. Therefore, this research describes the development of the overall PM system consists of a reliability analysis module, a failure mode effect analysis module, and maintenance request module.

Test-Retest Reliability of a Questionnaire for the Korea Youth Risk Behavior Web-Based Survey

  • Bae, Ji-Suk;Joung, Hyo-Jee;Kim, Jong-Yeon;Kwon, Kyoung-Nam;Kim, Young-Taek;Park, Soon-Woo
    • Journal of Preventive Medicine and Public Health
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    • v.43 no.5
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    • pp.403-410
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    • 2010
  • Objectives: A web-based survey has been administered annually since 2005 throughout Korea to assess the prevalence of adolescent health risk behaviors among middle and high school students. The aim of this study was to evaluate the test-retest reliability of the Korea Youth Risk Behavior Web-based Survey (KYRBWS) questionnaire. Methods: A convenience sample of 2298 middle and high school students participated in self-administered questionnaire surveys twice, approximately two weeks apart, in 2008. The percent agreement, kappa statistics, and prevalence rates at the first and second surveys were computed for the core subset of 39 self-reported health risk behavior indices of the KYRBWS. Results: Among 39 indices, seven indices had kappas $\geq$ 0.81 and all of the indices had kappas $\geq$ 0.41. Based on nonoverlapping 95% confidence intervals, three indices had significantly different prevalence rates between the first and second surveys. In the subgroup analyses by school grade and gender, two indices had significantly different reliability estimates between middle and high school students. There were no significantly different reliability estimates between male and female students, except for one index. Conclusions: This study demonstrated that the reliability estimates for the KYRBWS questionnaire are varied, but generally reliable over time. The indices with low reliability estimates need to be evaluated further in order to determine whether the indices should be modified or deleted from future versions of the KYRBWS.

RELIABILITY and VALIDITY of DUAL PROBE-FIXING FRAME for REHABILITATIVE ULTRASOUND IMAGING for EXERCISES with VISUAL FEEDBACK

  • Na-eun Byeon;Jang-hoon Shin;Wan-hee Lee
    • Physical Therapy Rehabilitation Science
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    • v.12 no.3
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    • pp.259-267
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    • 2023
  • Objective: Rehabilitative ultrasound imaging is a safe and noninvasive technique for evaluating muscle thickness. A dual probe-fixing frame (DPF) can provide visual feedback during exercises targeting specific muscles. The purpose of this research was to verify the reliability and validity of the DPF for dual-probe ultrasound (DPU)-based visual feedback exercises, allowing users to use both hands freely. Design: This cross-sectional study used repeated measures to compare muscle thickness measurements obtained using the handheld device and DPF with DPU. Methods: Twenty healthy adults participated in the study. Measurements were taken over two sessions, with a two-day interval between the sessions. The thicknesses of the rectus abdominis (RA) and transverse abdominis (TrA) muscles were measured using DPU. The DPF with DPU developed by the research team, was used along with a laptop-based muscle viewer. Bland-Altman analysis and intraclass correlation coefficients (ICCs) calculations were used in statistical analyses to evaluate agreement and reliability, respectively. Results: The results of the Bland-Altman analysis showed small average differences between the handheld and DPF methods for both RA and TrA muscle thicknesses. Inter-rater reliability analysis showed high ICC values for DPF measurements of both RA (0.908-0.912) and TrA (0.892-741) muscle thicknesses. Intra-rater reliability analysis also showed good ICC values for measurements taken by a single examiner over two days. Conclusion: The findings of this study demonstrate that the DPF provides reliable and valid measurements of muscle thickness during visual feedback exercises using the DPU.

Reliability Analyses of Breakwater Armor Blocks of Harbors in Korea (국내 항만의 방파제 피복 블록의 신뢰성 해석)

  • Kim, Seung-Woo;Suh, Kyung-Duck;Lee, Cheol-Eung;Park, Dong-Heon
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.1
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    • pp.15-29
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    • 2009
  • Most breakwater armor blocks are designed by using Hudson's or van der Meer's formula. The minimum weight of armor blocks is calculated by equating the resistance to the load in each formula. The larger value is then chosen as the design weight. In this study, we have performed reliability analyses for thus designed breakwater armor blocks of 12 trade harbors and 8 coastal harbors in Korea. The probability of failure calculated by the reliability analysis provides a criterion for evaluating the stability of armor blocks. The calculated probability of failure was almost same for all the breakwaters so that we were able to quantitatively evaluate the safety level of armor blocks of existing breakwaters. We also found that the safety factor used in the deterministic design method and the probability of failure in the reliability design method show a linear relationship. Therefore the probability of failure of existing breakwaters can be quantitatively calculated from the safety factors. The calculated probability of failure could also be used for determining the target probability of failure in the future.

An Evaluation Model for the Major Science Research Facilities and Equipments to Enhance the Competitiveness of the Science and Technology: A Focus on the Test of Reliability and Validity of the Model (과학기술 경쟁력 제고를 위한 대형연구시설 및 장비 평가모형 분석 : 모형의 신뢰성 및 타당성 검토를 중심으로)

  • Kwon, Gi-Heon;Cha, Yong-Jin;Lee, Hong-Jae
    • Journal of Korea Technology Innovation Society
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    • v.10 no.1
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    • pp.121-142
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    • 2007
  • The purpose of this study is to construct the evaluation model for the major science research facilities and equipments to enhance the competitiveness of the science and technology and also to test the reliability and validity of the model. To achieve the purposes, this study theoretically reviews the concept of the major science research facilities and equipments and their characteristics. Through a review of literature, this study draws 11 criteria for evaluating the priorities of the major science research facilities and equipments. These criteria are categorized as two dimensions - 'science & technology' and 'national policy'. The dimension of science & technology includes scientific importance, technological readiness, utilization rate, common utilization rate, and ability of management and operation. The national policy dimension contains degree of correspondence with national science development, imperativeness of national policy, science and technical effectiveness, economic and industrial effectiveness, responsiveness of research demand, and equity among the related institutions. The competitiveness of the science and technology consists of these two dimensions. The evaluation model is established on the framework of criteria. The 18 major science research facilities and equipments are selected through a series of Delphi. The survey of experts (BT, ET, IT, NT and ST) is also implemented to evaluate the 18 major science research facilities and equipments by 11 criteria. The overall results indicate that the reliability and validity of the model are good. The reliability tests show that the five indicators of science & technology and the six indicators of national policy have high internal consistencies. The confirmatory factor analyses reveal that the two constructs - 'science & technology' and 'national policy' - have high convergent and discriminant validity. The correlational analyses also show that the criteria-related validity between them is high. Furthermore, the results of higher order factor analysis indicate that the fit indices of the model are high and suggest a good fit to the data. Based on these findings, the policy implications of the model are discussed.

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Reliability-Based Assessment of Structural Safety of Steel-Concrete Hybrid Cable-Stayed Bridge Erected by the FCM and FSM during Construction (FCM과 FSM공법에 의한 강-콘크리트 복합사장교의 신뢰성에 기초한 시공간 구조안전도평가)

  • Yoon, Jung Hyun;Cho, Hyo Nam
    • Journal of Korean Society of Steel Construction
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    • v.19 no.5
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    • pp.515-526
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    • 2007
  • In this study, the models and methods for the safety assessment of Steel-Concrete Hybrid Cable-Stayed Bridge, which consists of steel composite girder and concrete girder erected by the FCM(Free Cantilever Method) and FSM(Full Staging Method) are proposed for the assurance of structural safety and the prevention against bridge collapse during construction. By the structural reliability approach that reasonably considers the uncertainties associated with the resistance and the load effect, the resistance and the load distribution characteristics of Steel-Concrete Hybrid Cable-Stayed Bridgeare defined and the strength limit state equations of permanent structures and temporary structures during construction are suggested. An AFOSM algorithm and MCS technique are used for the reliability analysis of cables, pylons, girders, steel-concrete conjunction part and temporary bents. Also, component reliability analyses are performed at the construction stages based on the structural system model. To demonstrate their rationality and practicality, the proposed models and approaches are applied to a real bridge. The sensitivity analyses of main parameters are performed in order to identify the critical factors that control the safety of similar bridges. As a result, it may be stated that the proposed models could be implemented as a rational and practical approach for the safety assessment of Steel-Concrete Hybrid Cable-stayed bridges erected by FCM and FSM during construction.