55 resultados para RELIABILITY ANALYSIS

em Deakin Research Online - Australia


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The probability of failure of a rock slope is generally estimated by using the Limit Equilibrium Method (LEM) in conjunction with a reliability analysis. Although the LEM is relatively simple and time efficient, recent studies have indicated that using the LEM may overestimate the factor of safety by 21%, when based on a non-linear failure criterion. Fortunately, the solutions presented by Li et al. (2008, 2009) can provide more accurate evaluations for rock slope stability as the numerical upper and lower bound limit analysis methods (2002a, 2002b, 2005) were employed. The advantages of these methods are used in this study to assess the rock slope probability of failure. The motivation is that with more accurate methods to evaluate the factor of safety, more economic designs can be performed.

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Failure Mode and Effect Analysis (FMEA) is a popular safety and reliability analysis methodology for examining potential failure modes of products, process, designs, or services, in a wide range of industries. Despite its popularity, there are a number of limitations of FMEA, and two highlighted issues are the bulky FMEA form and its intricacy of use. To overcome these shortcomings, we introduce the idea of visualisation pertaining to the failure modes or control actions in FMEA. A visualisation model with an incremental learning feature, i.e., the evolving tree (ETree), is adopted to allow the failure modes or control actions in FMEA to be clustered and visualized. The failure modes or control actions are grouped and visualized with consideration of their Severity, Occurrence, and Detection scores. Our proposed approach allows the failure modes or control actions to be mapped into a tree structure for visualisation. The devised approach is evaluated with a benchmark problem. The experiments show that the control actions of FMEA can be visualised through the tree structure, which provides a quick and easily understandable platform of the FMEA spreadsheet to facilitate decision making tasks.

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Failure mode and effect analysis (FMEA) is a popular safety and reliability analysis tool in examining potential failures of products, process, designs, or services, in a wide range of industries. While FMEA is a popular tool, the limitations of the traditional Risk Priority Number (RPN) model in FMEA have been highlighted in the literature. Even though many alternatives to the traditional RPN model have been proposed, there are not many investigations on the use of clustering techniques in FMEA. The main aim of this paper was to examine the use of a new Euclidean distance-based similarity measure and an incremental-learning clustering model, i.e., fuzzy adaptive resonance theory neural network, for similarity analysis and clustering of failure modes in FMEA; therefore, allowing the failure modes to be analyzed, visualized, and clustered. In this paper, the concept of a risk interval encompassing a group of failure modes is investigated. Besides that, a new approach to analyze risk ordering of different failure groups is introduced. These proposed methods are evaluated using a case study related to the edible bird nest industry in Sarawak, Malaysia. In short, the contributions of this paper are threefold: (1) a new Euclidean distance-based similarity measure, (2) a new risk interval measure for a group of failure modes, and (3) a new analysis of risk ordering of different failure groups. © 2014 The Natural Computing Applications Forum.

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BACKGROUND: It is important to assess young children's perceived Fundamental Movement Skill (FMS) competence in order to examine the role of perceived FMS competence in motivation toward physical activity. Children's perceptions of motor competence may vary according to the culture/country of origin; therefore, it is also important to measure perceptions in different cultural contexts. The purpose was to assess the face validity, internal consistency, test-retest reliability and construct validity of the 12 FMS items in the Pictorial Scale for Perceived Movement Skill Competence for Young Children (PMSC) in a Portuguese sample.

METHODS: Two hundred one Portuguese children (girls, n = 112), 5 to 10 years of age (7.6 ± 1.4), participated. All children completed the PMSC once. Ordinal alpha assessed internal consistency. A random subsamples (n = 47) were reassessed one week later to determine test-retest reliability with Bland-Altman method. Children were asked questions after the second administration to determine face validity. Construct validity was assessed on the whole sample with a Bayesian Structural Equation Modelling (BSEM) approach. The hypothesized theoretical model used the 12 items and two hypothesized factors: object control and locomotor skills.

RESULTS: The majority of children correctly identified the skills and could understand most of the pictures. Test-retest reliability analysis was good, with an agreement ration between 0.99 and 1.02. Ordinal alpha values ranged from acceptable (object control 0.73, locomotor 0.68) to good (all FMS 0.81). The hypothesized BSEM model had an adequate fit.

CONCLUSIONS: The PMSC can be used to investigate perceptions of children's FMS competence. This instrument can also be satisfactorily used among Portuguese children.

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Failure mode and effect analysis (FMEA) is a popular safety and reliability analysis tool in examining potential failures of products, process, designs, or services, in a wide range of industries. While FMEA is a popular tool, the limitations of the traditional Risk Priority Number (RPN) model in FMEA have been highlighted in the literature. Even though many alternatives to the traditional RPN model have been proposed, there are not many investigations on the use of clustering techniques in FMEA. The main aim of this paper was to examine the use of a new Euclidean distance-based similarity measure and an incremental-learning clustering model, i.e., fuzzy adaptive resonance theory neural network, for similarity analysis and clustering of failure modes in FMEA; therefore, allowing the failure modes to be analyzed, visualized, and clustered. In this paper, the concept of a risk interval encompassing a group of failure modes is investigated. Besides that, a new approach to analyze risk ordering of different failure groups is introduced. These proposed methods are evaluated using a case study related to the edible bird nest industry in Sarawak, Malaysia. In short, the contributions of this paper are threefold: (1) a new Euclidean distance-based similarity measure, (2) a new risk interval measure for a group of failure modes, and (3) a new analysis of risk ordering of different failure groups.

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To test the potential value of McVay's (2000) Readiness for Online Learning questionnaire for research and practice, the instrument was administered to 107 undergraduate university students drawn from a range of courses in the United States and Australia. The questionnaire was subjected to a reliability analysis and a factor analysis. The instrument fared well in the reliability analysis, and yielded a two-factor structure that was readily interpretable in a framework of existing theory and research. Factors identified were "Comfort with e-learning" and "Self-management of learning." It is suggested that the instrument is useful for both research and practice, but would be enhanced through further work on 5 of the 13 items. Additionally, further work is required to establish predictive validity.

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Background: Physical educators are faced with trying to provide motivating and enjoyable experiences in physical education. Sport Education is an instructional model that aims to provide positive motivational sport experiences by simulating the features of authentic sport. Research support for Sport Education is positive, however, the effects on student motivation and the motivational climate are not well understood.

Purpose
: To investigate the influence of the Sport Education model on student motivation (intrinsic/extrinsic motivation, goal orientations, and perceived motivational climate) in secondary physical education.

Setting: Six classes were selected according to teacher and class availability in the sports of soccer, hockey, and football codes in a co-educational government school.

Participants: Participants were 115 (male = 97, female = 18) Year-8 students (aged 13-14 years), in a Sport Education condition (n = 41) and a Traditional condition (n = 74).

Measures: At pre- and post-test, all participants completed three questionnaires: the Intrinsic Motivation Inventory, the Task and Ego Orientation in Sport Questionnaire, and the Perceived Motivational Climate in Sport Questionnaire.

Intervention: Participants completed either a Sport Education condition or a Traditional condition for one double period (100 minutes) one day per week for 10 weeks (Sport Education condition) or for five weeks (Traditional condition). The Sport Education condition incorporated six distinctive features: seasons, affiliation, formal competition, record keeping, festivity, and a culminating event. The Traditional condition used whole-group instruction led by the teacher.

Research design: The study used a non-equivalent control group design with pre- and post-test procedures. The independent variable was teaching condition and the dependent variable was student motivation (assessed by intrinsic motivation, goal orientations, and motivational climate). The groups were already established and selected for convenience purposes.

Data collection and analysis: Participants completed pre-test measures and then participated in their pre-established classes. Post-test measures were completed in the last class in each condition. A reliability analysis on measures was conducted using Cronach's alphas. A pre-test manipulation check was performed to check for any initial differences in motivation. To compare the difference in changes between conditions on motivation, a series of 2 times 2 repeated measures analyses of variance were conducted. A comparison of the relationship between motivation measures was conducted using Pearson's product moment correlation coefficients.

Findings: There was a significant difference between the conditions on changes in perceived competence, task orientation, and mastery climate, with the Traditional condition decreasing significantly from pre- to post-test compared with the Sport Education condition. There were no significant differences on interest/enjoyment, effort/importance, pressure/tension, ego orientation, or performance climate. A mastery climate was positively related to task orientation and intrinsic motivation and a performance climate was related to ego orientation.

Conclusions: The Sport Education condition was more successful in maintaining high levels of intrinsic motivation, task orientation, and mastery climate than the Traditional condition. That is, the Traditional condition was associated with a decrease in adaptive aspects of motivation for students, whereas the Sport Education condition maintained existing levels of motivation.

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In the existing studies on fault-tolerant scheduling, the active replication schema makes use of ε + 1 replicas for each task to tolerate ε failures. However, in this paper, we show that it does not always lead to a higher reliability with more replicas. Besides, the more replicas implies more resource consumption and higher economic cost. To address this problem, with the target to satisfy the user’s reliability requirement with minimum resources, this paper proposes a new fault tolerant scheduling algorithm: MaxRe. In the algorithm, we incorporate the reliability analysis into the active replication schema and the theoretical analysis and experiments prove that the MaxRe algorithm’s schedule can certainly satisfy user’s reliability requirements. And the MaxRe scheduling algorithm can achieve the corresponding reliability with at most 70% fewer resources than the FTSA algorithm.

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PURPOSE: The purpose of this study was to test the internal consistency and construct validity of the revised 12-item self-rated Partners in Health (PIH) scale used to assess patients' chronic condition self-management knowledge and behaviours. METHODS: Baseline PIH data were collected for a total of 294 patients with a range of co-morbid chronic conditions including diabetes, cardiovascular disease and arthritis. Scale data for the initial sample of 176 patients were analysed for internal consistency and construct validity using Reliability Analysis and Factor Analysis. Construct validity was tested in a separate sample of 118 patients using confirmatory factor analysis and a structural equation model. RESULTS: Good internal consistency was indicated with a Cronbach's alpha coefficient of 0.82 in the initial sample. Factor analysis for this sample revealed four key factors (knowledge, coping, management of condition and adherence to treatment) across the twelve items of the scale. These four key factors were then confirmed by applying the exploratory structural equation model to the separate sample. CONCLUSION: The PIH scale exhibits construct validity and internal consistency. It therefore is both a generic self-rated clinical tool for assessing self-management in a range of chronic conditions as well as an outcome measure to compare populations and change in patient self-management knowledge and behaviour over time. The four domains of self-management provide a valid measure of patient competency in relation to the self-management of their chronic condition(s).

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The purpose of this study was to assess the ability of observers to use voice-recognition analysis to accurately classify gait transitions and quantify gait durations typical of team games. Inter-rater and intra-rater reliability was also determined. Four males were filmed performing pre-determined gait protocols, each comprising different sequences of walking, jogging. running and sprinting. Two operators independently classified gait transitions and the time spent in each gait was determined by the voice recognition system. All gait modes as measured by trained observers demonstrated statistically significant correlations (p<O.O I) to predetermined measurement criteria. The mean absolute error for all gait transitions was less than half a second (0.32-0.36 5) with the maximum percentage error being approximately 4% for the walk, jog and run gaits and 10% for sprinting. Gait classification error was low at 1-9%. The intra-rater and inter-rater reliability was consistently high ranging from r =' 0.87 to 0.99. In conclusion, observers using voice-recognition software provided valid measures of time spent in each of the four gait categories with 90% or better accuracy achieved.

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Building design decisions are commonly based on issues pertaining to construction cost, and consideration of energy performance is made only within the context of the initial project budget. Even where energy is elevated to more importance, operating energy is seen as the focus and embodied energy is nearly always ignored. For the first time, a large sample of buildings has been assembled and analysed in a single study to improve the understanding of the relationship between energy and cost performance over their full life cycle. Thirty recently completed buildings in Melbourne, Australia have been studied to explore the accuracy of initial embodied energy prediction based on capital cost at various levels of model detail. The embodied energy of projects, elemental groups, elements and selected items of work are correlated against capital cost and the strength of the relationship is computed. The relationship between initial embodied energy and capital cost generally declines as the predictive model assumes more detail, although elemental modelling may provide the best solution on balance.

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Acceptable reliability of normalisation contractions in electromyography (EMG) is paramount for testing conducted over a number of days or if normal laboratory strength testing equipment is unavailable. This study examined the reliability of maximal voluntary isometric contractions (MVIC) and sub-maximal (60%) isometric contractions for use in neck muscle EMG studies. Surface EMG was recorded bilaterally from eight sites around the neck at C4/5 level from five healthy male subjects. Subjects performed MVIC and sub-maximal normalisation contractions using an isokinetic dynamometer (ID) and a portable cable dynamometer with attached strain gauge (PCD) in addition to a MVIC against a manual resistance (MR). Subjects were tested in flexion, extension, left and right lateral bending and were retested by the same tester within a two-week period. Intra class correlation co-efficients (ICC) were calculated for each testing method and contraction direction and a mean ICC was calculated across all contraction directions. All normalisation methods produced excellent within-day reliability (mean ICC >0.80) but only the MVICs using the ID and PCD had acceptable reliability when assessed between-days. This study confirmed the validity of using MVICs elicited using the ID and PCD as reliable reference contractions for the normalisation of neck EMG.

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Fast-food outlets are a significant subsector of the hospitality and tourism property market in Australia, and have experienced significant growth and global change in the past 20 years. However, little attention has been given in professional and academic literature to the valuation methodology and analysis of these properties. This article proposes a working definition of a fast-food outlet, traces recent changes in the structure of the fast-food industry, investigates the major determinants of value with respect to asset value, and examines to what extent these have changed. In particular, it isolates the role of goodwill in assessing going-concern value.

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Fast food outlets are a significant sub sector of the Hospitality and Tourism Property Market and a specialized form of business. This form of hospitality outlet has experienced significant growth and change in the last 20 years. Their value as an asset is therefore of significant interest to many involved in the tourism and hospitality industry, not least fast food operators or potential operators and their financiers. However, little attention has been given in professional and academic literature to valuation methodology, the analysis of the major components of asset value, and the underlying factors which influence asset value. As such the reliability of the valuation process could justifiably be questioned.
This paper sets out a working definition of a fast food outlet. It investigates the major determinants of value with respect to asset value and examines the accepted methods of valuation of fast food outlets in Australia as well as establishing the methods most commonly used. It clarifies the major components of asset value and examines to what extent these have changed with the changing business environment. In particular it isolates the role of Goodwill in assessing Going Concern Value. Sources of data include a comprehensive literature review and personal interviews with professionals involved in the valuation process. The paper concludes that an efficient valuation process requires that fast food outlets be considered as both a real estate and business investment. The contribution of both tangible and intangible assets to the value of the asset must be identified.

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The ability to uniquely identify individual objects is essential in many applications such as manufacturing, distribution logistics, access control, anti-counterfeiting and healthcare. Radio Frequency Identification (RFID) technology provides one solution for automatic identification of entities using radio waves. Although there is considerable potential in deploying RFID technology, reliability is a key challenge that requires careful attention for RFID to deliver its inherent benefits. In this paper, we highlight the reliability challenges in RFID technology and we analyze the reliability aspects of RFID technology and their major causes. We will also discuss techniques to improve the reliability of RFID systems.