Sample records for reliability short repairtime

  1. Capacitive effects in IGBTs limiting their reliability under short circuit

    Reigosa, Paula Diaz; Iannuzzo, Francesco; Rahimo, Munaf


    The short-circuit oscillation mechanism in IGBTs is investigated in this paper by the aid of semiconductor device simulation tools. A 3.3-kV IGBT cell has been used for the simulations demonstrating that a single IGBT cell is able to oscillate together with the external circuit parasitic elements....... The work presented here through both circuit and device analysis, confirms that the oscillations can be understood with focus on the device capacitive effects coming from the interaction between carrier concentration and the electric field. The paper also shows the 2-D effects during one oscillation cycle...

  2. Reliability and validity of the short form Beck Depression Inventory with older adults.

    Scogin, F; Beutler, L; Corbishley, A; Hamblin, D


    This study investigated the reliability and validity of the short form Beck Depression Inventory with older adults. Sixty-one clinically depressed older outpatients and 57 non-patient older volunteers comprised the sample. The patient group completed the BDI prior to and at completion of depression treatment. Estimates of internal reliability suggest that the short form BDI possesses adequate Spearman-Brown and alpha coefficients. Congruent validity estimates were less satisfactory, as the correlation between the BDI and the HRSD was statistically significant, but low. Criterion group validity, diagnostic sensitivity, and sensitivity to change estimates were all acceptable. Thus, the short form BDI is adequately reliable to suggest its use as a research and clinical tool with older adults, although further study of the instrument's validity is needed.

  3. Reliability of Three Benton Judgment of Line Orientation Short Forms in Idiopathic Parkinson’s Disease

    Gullett, Joseph M.; Price, Catherine C.; Nguyen, Peter; Okun, Michael S.; Bauer, Russell M.; Bowers, Dawn


    Individuals with Parkinson’s disease (PD) often exhibit deficits in visuospatial functioning throughout the course of their disease. These deficits should be carefully assessed as they may have implications for patient safety and disease severity. One of the most commonly administered tests of visuospatial ability, the Benton Judgment of Line Orientation (JLO), consists of 30 pairs of lines requiring the patient to match the orientation of two lines to an array of 11 lines on a separate page. Reliable short forms have been constructed out of the full JLO form, but the reliability of these forms in PD has yet to be examined. Recent functional MRI studies examining the JLO demonstrate right parietal and occipital activation, as well as bilateral frontal activation and PD is known to adversely affect these pathways. We compared the reliability of the original full form to three unique short forms in a sample of 141 non-demented, idiopathic PD patients and 56 age and education matched controls. Results indicated that a two-thirds length short form can be used with high reliability and classification accuracy in patients with idiopathic PD. The other short forms performed in a similar, though slightly less reliable manner. PMID:23957375

  4. Reliability of short form-36 in an Internet- and a pen-and-paper version

    Basnov, Maja; Kongsved, Sissel Marie; Bech, Per;


    Use of Internet versions of questionnaires may have several advantages in clinical and epidemiological research, but we know little about if Internet versions differ with respect to validity and reliability. We aimed to compare Internet- and pen-and-paper versions of short form-36 (SF-36) with re...


    Erhan F.


    Full Text Available In the article the analysis of the influence level current of the short circuit of the electrical equipment. It is designed the mathematical model allowing the modeling prototype reliability of the operation electrical equipment installed in nodes of the systems.

  6. A short questionnaire to evaluate the effectiveness of tutors in PBL: validity and reliability.

    Dolmans, Diana H J M; Ginns, Paul


    The tutor plays a central role in problem-based learning (PBL). In many PBL-curricula the effectiveness of the tutor is evaluated in order to provide tutors with feedback. In the literature, several tutor evaluation instruments have been described. The problem with many of these instruments is that they are quite long, due to which students become 'tired' of filling them out. Using a short questionnaire is more convenient for students, but the question is whether such a short instrument can be valid and reliable. The purpose of this article is to demonstrate the validity and reliability of a short questionnaire (11 items), representing five underlying factors. A confirmatory factor analysis was carried out to assess the adequacy of the five factors. The results demonstrated that the five factor model had a good fit to the data. The alpha coefficients also demonstrated acceptable levels. In conclusion, the short tutor evaluation instrument (11 items) is reliable and valid and can be used for formative and summative purposes.

  7. Reliability of short form-36 in an Internet- and a pen-and-paper version

    Basnov, Maja; Kongsved, Sissel Marie; Bech, Per


    Use of Internet versions of questionnaires may have several advantages in clinical and epidemiological research, but we know little about if Internet versions differ with respect to validity and reliability. We aimed to compare Internet- and pen-and-paper versions of short form-36 (SF-36) with re......Use of Internet versions of questionnaires may have several advantages in clinical and epidemiological research, but we know little about if Internet versions differ with respect to validity and reliability. We aimed to compare Internet- and pen-and-paper versions of short form-36 (SF-36......) with respect to test-retest reliability and internal consistency. Women referred to mammography (n = 782) were randomised to receive either a paper version with a prepaid return envelope or a guideline on how to fill in the Internet version. A subgroup was asked to answer the questionnaire once again...... in the alternative version. Test-retest reliability was assessed by the intra-class correlation coefficient. Internal consistency was calculated as Cronbach's alpha. The between-version test-retest reliability for the eight subscales were between 0.63 and 0.92. Cronbach's alpha for the two versions were all between...

  8. Reliability testing of the Danish version of the Kidney Disease Quality of Life Short Form

    Molsted, Stig; Heaf, James; Prescott, Lotte


    OBJECTIVE: The questionnaire Kidney Disease Quality of Life Short Form version 1.3 (KDQOL-SF) is valuable for assessing the health-related quality of life in patients treated with chronic dialysis. The aim of this study was to translate and test the reliability of the KDQOL-SF for use in Denmark...... involving all patients, two of the disease-specific scales had Cronbach's alpha coefficients of ... of peritoneal dialysis (PD) patients discovered low reliability for three disease-specific scales. The KDQOL-SF manual and the Danish manual for the Short Form 36 (SF36) differed in the scoring of four generic scales: "role limitation-physical", "bodily pain", "general health" and "social function". CONCLUSIONS...

  9. Portuguese validation of the Short Health Anxiety Inventory: Factor structure, reliability, and factor invariance.

    Morales, Alexandra; Reis, Sibília; Espada, José P; Orgilés, Mireia


    The Short Health Anxiety Inventory is a brief instrument to assess health anxiety widely used across countries; however, no validated version is available for Portuguese-speaking population. Factorial structure, reliability, and equivalency factor with the Spanish version were analyzed with Portuguese adolescents aged 14-18 years. A Portuguese adolescent cohort ( N = 629) and a comparative Spanish adolescent cohort ( N = 1502) were evaluated. The original two-factor version was the best fitting model for the Portuguese version. The reliability was excellent. Complete measurement invariance across both countries was supported. The Portuguese version of the Short Health Anxiety Inventory is a valid screening inventory to assess health anxiety in adolescents.

  10. The Behaviour Problems Inventory-Short Form: Reliability and Factorial Validity in Adults with Intellectual Disabilities

    Mascitelli, Andréa N.; Rojahn, Johannes; Nicolaides, Vias C.; Moore, Linda; Hastings, Richard P.; Christian-Jones, Ceri


    Background: The Behaviour Problems Inventory-Short Form (BPI-S) is a spin-off of the BPI-01 that was empirically developed from a large BPI-01 data set. In this study, the reliability and factorial validity of the BPI-S was investigated for the first time on newly collected data from adults with intellectual disabilities. Methods: The sample…

  11. The Behaviour Problems Inventory-Short Form: Reliability and Factorial Validity in Adults with Intellectual Disabilities

    Mascitelli, Andréa N.; Rojahn, Johannes; Nicolaides, Vias C.; Moore, Linda; Hastings, Richard P.; Christian-Jones, Ceri


    Background: The Behaviour Problems Inventory-Short Form (BPI-S) is a spin-off of the BPI-01 that was empirically developed from a large BPI-01 data set. In this study, the reliability and factorial validity of the BPI-S was investigated for the first time on newly collected data from adults with intellectual disabilities. Methods: The sample…

  12. Half-Year Retest-Reliability of the Barratt Impulsiveness Scale–Short Form (BIS-15

    Adrian Meule


    Full Text Available One of the most widely used instruments for the measurement of impulsivity is the Barratt Impulsiveness Scale (BIS-11. The short form of the BIS-11, the BIS-15, consists of 15 items representing the three subscales Attentional, Motor, and Non-Planning Impulsivity. In the current study, retest-reliabilities of BIS-15 scores were examined. Female university students completed the BIS-15 at the beginning of the first (n = 133 and second (n = 120 semesters. Half-year retest-reliability was rtt = .79 for the BIS-15 total score and ranged between rtt = .61 and .78 for the subscales. Considering the long time span of almost half a year between measurements, the total score of the BIS-15 has high retest-reliability and, thus, measures impulsivity as a stable personality trait.

  13. Reliability and validity of the Korean version of the Short Musculoskeletal Function Assessment questionnaire for patients with musculoskeletal disorder.

    Jung, Kyoung-Sim; Jung, Jin-Hwa; In, Tae-Sung; Cho, Hwi-Young


    [Purpose] The purpose of this study was to establish the reliability and validity of the Short Musculoskeletal Function Assessment questionnaire, which was translated into Korean, for patients with musculoskeletal disorder. [Subjects and Methods] Fifty-five subjects (26 males and 29 females) with musculoskeletal diseases participated in the study. The Short Musculoskeletal Function Assessment questionnaire focuses on a limited range of physical functions and includes a dysfunction index and a bother index. Reliability was determined using the intraclass correlation coefficient, and validity was examined by correlating short musculoskeletal function assessment scores with the 36-item Short-Form Health Survey (SF-36) score. [Results] The reliability was 0.97 for the dysfunction index and 0.94 for the bother index. Validity was established by comparison with Korean version of the SF-36. [Conclusion] This study demonstrated that the Korean version of the Short Musculoskeletal Function Assessment questionnaire is a reliable and valid instrument for the assessment of musculoskeletal disorders.

  14. Reliability of a patient survey assessing "Short Form Injury Questionnaire 7" in Iran

    Mahdi Sharif-Alhoseini; Soheil Saadat; Afarin Rahimi-Movaghar; Abbas Motevalian; Masoumeh Amin-Esmaeili; Mitra Hefazi; Vafa Rahimi-Movaghar


    Objective: Injury is a major cause of morbidity and mortality in the world.The assessment of patterns and severity of injury in high-risk groups is crucial for planning and service development.On a large scale national household survey,we estimated the annual incidence and the patterns of injury,the demographics of the injured people,as well as the service use for all injuries in Iran.The current study aims at assessing the reliability of the questionnaire before carrying out a national survey.Methods: In a pilot study using cluster random sampling approach,73 people were interviewed.The interviewers asked the participants to report all injuries occurred in them and the care provided during the previous 12 months,based on "Short Form Injury Questionnaire 7".About two weeks later,the interview was repeated by another interviewer.Results: In our test-retest reliability,Kappa score was good for three and moderate for four questions.The question on the injured organ had the highest test-retest reliability with a Kappa score of 0.84.Conclusions:The reliability of the questionnaire and the procedure of questioning are confirmed.The questionnire is proper for utilization in large national surveies.

  15. A least squares approach for efficient and reliable short-term versus long-term optimization

    Christiansen, Lasse Hjuler; Capolei, Andrea; Jørgensen, John Bagterp


    the balance between the objectives, leaving an unfulfilled potential to increase profits. To promote efficient and reliable short-term versus long-term optimization, this paper introduces a natural way to characterize desirable Pareto points and proposes a novel least squares (LS) method. Unlike hierarchical...... approaches, the method is guaranteed to converge to a Pareto optimal point. Also, the LS method is designed to properly balance multiple objectives, independently of Pareto front’s shape. As such, the method poses a practical alternative to a posteriori methods in situations where the frontier is intractable...

  16. The intra- and inter-rater reliabilities of the Short Form Berg Balance Scale in institutionalized elderly people.

    Kim, Seong-Gil; Kim, Myoung-Kwon


    [Purpose] The purpose of this study was to examine the intra- and inter-rater reliabilities of the Short Form Berg Balance Scale in institutionalized elderly people. [Subjects and Methods] A total of 30 elderly people in a nursing facility in Y city, South Korea, participated in this study. Two examiners administered the Short Form Berg Balance Scale to one subject to investigate inter-rater reliability. After a week, the same examiners administered the Short Form Berg Balance Scale once more to investigate intra-rater reliability. [Results] The intra-rater reliability was 0.83. The inter-rater reliability was 0.79. Both reliabilities were high (more than 0.7). [Conclusion] The Short Form Berg Balance Scale is a version of the Berg Balance Scale shortened by reducing the number of items, but its reliabilities were not lower than those of the Berg Balance Scale. The Short Form Berg Balance Scale can be useful clinically due to its short measurement time.

  17. Reliability and validity of the Japanese version of the Resilience Scale and its short version

    Kondo Maki


    Full Text Available Abstract Background The clinical relevance of resilience has received considerable attention in recent years. The aim of this study is to demonstrate the reliability and validity of the Japanese version of the Resilience Scale (RS and short version of the RS (RS-14. Findings The original English version of RS was translated to Japanese and the Japanese version was confirmed by back-translation. Participants were 430 nursing and university psychology students. The RS, Center for Epidemiologic Studies Depression Scale (CES-D, Rosenberg Self-Esteem Scale (RSES, Social Support Questionnaire (SSQ, Perceived Stress Scale (PSS, and Sheehan Disability Scale (SDS were administered. Internal consistency, convergent validity and factor loadings were assessed at initial assessment. Test-retest reliability was assessed using data collected from 107 students at 3 months after baseline. Mean score on the RS was 111.19. Cronbach's alpha coefficients for the RS and RS-14 were 0.90 and 0.88, respectively. The test-retest correlation coefficients for the RS and RS-14 were 0.83 and 0.84, respectively. Both the RS and RS-14 were negatively correlated with the CES-D and SDS, and positively correlated with the RSES, SSQ and PSS (all p Conclusions This study demonstrates that the Japanese version of RS has psychometric properties with high degrees of internal consistency, high test-retest reliability, and relatively low concurrent validity. RS-14 was equivalent to the RS in internal consistency, test-retest reliability, and concurrent validity. Low scores on the RS, a positive correlation between the RS and perceived stress, and a relatively low correlation between the RS and depressive symptoms in this study suggest that validity of the Japanese version of the RS might be relatively low compared with the original English version.

  18. Reliability and validity of a short form household food security scale in a Caribbean community

    Mahabir Deepak


    Full Text Available Abstract Background We evaluated the reliability and validity of the short form household food security scale in a different setting from the one in which it was developed. Methods The scale was interview administered to 531 subjects from 286 households in north central Trinidad in Trinidad and Tobago, West Indies. We evaluated the six items by fitting item response theory models to estimate item thresholds, estimating agreement among respondents in the same households and estimating the slope index of income-related inequality (SII after adjusting for age, sex and ethnicity. Results Item-score correlations ranged from 0.52 to 0.79 and Cronbach's alpha was 0.87. Item responses gave within-household correlation coefficients ranging from 0.70 to 0.78. Estimated item thresholds (standard errors from the Rasch model ranged from -2.027 (0.063 for the 'balanced meal' item to 2.251 (0.116 for the 'hungry' item. The 'balanced meal' item had the lowest threshold in each ethnic group even though there was evidence of differential functioning for this item by ethnicity. Relative thresholds of other items were generally consistent with US data. Estimation of the SII, comparing those at the bottom with those at the top of the income scale, gave relative odds for an affirmative response of 3.77 (95% confidence interval 1.40 to 10.2 for the lowest severity item, and 20.8 (2.67 to 162.5 for highest severity item. Food insecurity was associated with reduced consumption of green vegetables after additionally adjusting for income and education (0.52, 0.28 to 0.96. Conclusions The household food security scale gives reliable and valid responses in this setting. Differing relative item thresholds compared with US data do not require alteration to the cut-points for classification of 'food insecurity without hunger' or 'food insecurity with hunger'. The data provide further evidence that re-evaluation of the 'balanced meal' item is required.

  19. A Validation Study of the Dutch Childhood Trauma Questionnaire-Short Form: Factor Structure, Reliability, and Known-Groups Validity

    Thombs, Brett D.; Bernstein, David P.; Lobbestael, Jill; Arntz, Arnoud


    Objective: The 28-item Childhood Trauma Questionnaire-Short Form (CTQ-SF) has been translated into at least 10 different languages. The validity of translated versions of the CTQ-SF, however, has generally not been examined. The objective of this study was to investigate the factor structure, internal consistency reliability, and known-groups…

  20. Short-Term and Medium-Term Reliability Evaluation for Power Systems With High Penetration of Wind Power

    Ding, Yi; Singh, Chanan; Goel, Lalit;


    The expanding share of the fluctuating and less predictable wind power generation can introduce complexities in power system reliability evaluation and management. This entails a need for the system operator to assess the system status more accurately for securing real-time balancing. The existing...... a useful tool for the system operator to evaluate the reliability and arrange reserve for maintaining secure system operation in the short- as well as medium-terms....... an approximation of the time-varying behavior of power systems with high penetration of wind power. This paper proposes a time-varying reliability assessment technique. Time-varying reliability models for wind farms, conventional generating units, and rapid start-up generating units are developed and represented...

  1. Validity and reliability of short form-12 questionnaire in Iranian hemodialysis patients

    Pakpour, Amir H; Nourozi, Saeedeh; Molsted, Stig


    The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis.......The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis....

  2. In search of parsimony: reliability and validity of the Functional Performance Inventory-Short Form

    Nancy Kline Leidy


    Full Text Available Nancy Kline Leidy1, Ann Knebel21Center for Health Outcomes Research, United BioSource Corporation, Bethesda, MD, USA; 2Office of the Assistant Secretary for Preparedness and Response, US Department of Health and Human Services, Washington, DC, USAPurpose: The 65-item Functional Performance Inventory (FPI, developed to quantify functional performance in patients with chronic obstructive pulmonary disease (COPD, has been shown to be reliable and valid. The purpose of this study was to create a shorter version of the FPI while preserving the integrity and psychometric properties of the original.Patients and methods: Secondary analyses were performed on qualitative and quantitative data used to develop and validate the FPI long form. Seventeen men and women with COPD participated in the qualitative work, while 154 took part in the mail survey; 54 completed 2-week reproducibility assessment, and 40 relatives contributed validation data. Following a systematic process of item reduction, performance properties of the 32-item short form (FPI-SF were examined.Results: The FPI-SF was internally consistent (total scale α = 0.93; subscales: 0.76–0.89 and reproducible (r = 0.88; subscales: 0.69–0.86. Validity was maintained, with significant (P < 0.001 correlations between the FPI-SF and the Functional Status Questionnaire (activities of daily living, r = 0.71; instrumental activities of daily living, r = 0.73, Duke Activity Status Index (r = 0.65, Bronchitis-Emphysema Symptom Checklist (r = -0.61, Basic Need Satisfaction Inventory (r = 0.61 and Cantril’s Ladder of Life Satisfaction (r = 0.63, and Katz Adjustment Scale for Relatives (socially expected activities, r = 0.51; free-time activities, r = -0.49, P < 0.01. The FPI-SF differentiated patients with an FEVl% predicted greater than and less than 50% (t = 4.26, P < 0.001, and those with severe and moderate levels of perceived severity and activity limitation (t = 9.91, P < 0.001.Conclusion: Results

  3. Development of Reliable and Valid Short Forms of the Marlowe-Crowne Social Desirability Scale.

    Reynolds, William M.


    Developed, on the basis of responses from 608 undergraduate students to the 33-item Marlowe-Crowne Social Desirability Scale, three short forms of the scale. Comparisons made between the short forms examined in this investigation suggest the 13-item form as a viable substitute for the regular 33-item Marlowe-Crowne scale. (Author)

  4. [Development of a short form of the Japanese big-five scale, and a test of its reliability and validity].

    Namikawa, Tsutomu; Tani, Iori; Wakita, Takafumi; Kumagai, Ryuichi; Nakane, Ai; Noguchi, Hiroyuki


    Personality scales based on the five-factor model, especially the big-five scale of personality trait adjectives (Wada, 1996), are commonly used in Japan. In this study a short form of the Big-Five Scale was constructed. To avoid changes in the capacity dimension caused by the decrease in the number of items, item selection was conducted after item response theory (IRT) scales were constructed for all the items. In study 1 data was collected from 2099 participants. A generalized partial credit model was applied to the IRT model, and items were selected using the slope and location parameters for each item. Cronbach's alpha showed that the short form, as well as the five sub-scales, had sufficient reliability as a personality test. In study 2, we determined correlations with the NEO-FFI and tested the concurrent validity of the short form. The results indicate that the short form of big-five scale demonstrates sufficient reliability and validity despite the reduced number of items.

  5. Validity and reliability of short form-12 questionnaire in Iranian hemodialysis patients

    Pakpour, Amir H.; Nourozi, Saeedeh; Mølsted, Stig


    and construct validity on the patient group as a whole. A linear regression analysis was used to assess any variation in the physical component summary and mental component summary scores of the SF-36 with the respective component summary scores of the SF-12. In addition, the factor structure......INTRODUCTION: The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis. MATERIALS AND METHODS: One hundred and forty-four hemodialysis patients were included from dialysis centers in Zanjan, Iran, and were...... asked to complete the SF-12 and SF-36 questionnaires. An initial test-retest reliability evaluation was performed on a sample of 70 patients from the total group, with a retest interval of 14 days. Reliability was estimated by internal consistency and validity was assessed using known-group comparisons...

  6. Reliability of the Test of Wheeled Mobility (TOWM) and the Short Wheelie Test

    Fliess-Douer, Osnat; Van der Woude, Lucas H. V.; Vanlandewijck, Yves C.


    Objective: To assess the reliability of the Test of Wheeled Mobility (TOWM) and the Wheelie test. Design: Cohort study. Setting: Gymnasium. Participants: Manual wheelchair users (N=30, age 23-53y) with a spinal cord injury. Intervention: Participants performed the 30 skills of the TOWM and the 8 ski

  7. Validity and reliability of short form-12 questionnaire in Iranian hemodialysis patients

    Pakpour, Amir H.; Nourozi, Saeedeh; Molsted, Stig


    INTRODUCTION: The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis. MATERIALS AND METHODS: One hundred and forty-four hemodialysis patients were included from dialysis centers in Zanjan, Iran, and were a...

  8. Reliability and validity of the assessment of depression in general practice : the Short Depression Interview (SDI)

    Terluin, B; van Hout, HPJ; van Marwijk, HWJ; Ader, HJ; van der Meer, K; de Haan, M; van Dyck, R


    General practitioners (GPs) are recommended to use DSM-IV criteria to diagnose major depression in daily clinical practice. This implies the assessment of nine depressive symptoms and four additional criteria. A short structured interview has been developed to assess these symptoms and criteria, and

  9. Urine collection in the freely moving rat : Reliability for measurement of short-term renal effects

    Haas, M; Kluppel, A.C A; Moolenaar, Frits; Meijer, D.K F; de Jong, P.E; de Zeeuw, D


    Studies on short-term renal responses to (pharmacological) intervention require accurate and multiple collection of urine samples. Several invasive techniques have been described for frequent urine collection of the conscious rat, each having their own limitations. No data are available about the fe

  10. Sentinel node detection after preoperative short-course radiotherapy in rectal carcinoma is not reliable

    Braat, AE; Moll, FCP; de Vries, JE; Wiggers, T


    Background: Seninel node (SN) detection may be used in patients with colonic carcinoma. However, its use in patients with rectal carcinoma may be unreliable. To address this, SN detection was evaluated in patients with rectal carcinoma after short-course preoperative radiotherapy. Methods: Patent Bl

  11. Reliability of BOD POD Measurements Remains High After a Short-Duration Low-Carbohydrate Diet.

    Greer, Beau Kjerulf; Edsall, Kathleen M; Greer, Anna E


    The purpose of the current study was to determine whether expected changes in body weight via a 3-day low-carbohydrate (LC) diet will disrupt the reliability of air displacement plethysmography measurements via BOD POD. Twenty-four subjects recorded their typical diets for 3 days before BOD POD and 7-site skinfold analyses. Subjects were matched for lean body mass and divided into low-CHO (LC) and control (CON) groups. The LC group was given instruction intended to prevent more than 50 grams/day of carbohydrate consumption for 3 consecutive days, and the CON group replicated their previously recorded diet. Body composition measurements were repeated after dietary intervention. Test-retest reliability measures were significant (p BOD POD measurements for body mass (72.9 ± 13.3 vs. 72.1 ± 13.0 kg [M ± SD]) and body volume (69.0 ± 12.7-68.1 ± 12.2 L) in the LC group (p .05) in BOD POD-determined body fat percentage, lean body mass, or fat mass between the 1st and 2nd trial in either group. Body composition measures via BOD POD and 7-site skinfolds remain reliable after 3 days of an LC diet despite significant decreases in body mass.

  12. Validity and reliability of 5 Hz GPS devices on short career with change of direction

    David Casamichana Gómez, Julen Castellano Paulis


    Full Text Available The aim of this study was to assess the validity and reliability of a MinimaxX GPS device (Team Sport 2.5, Catapult Innovations operating with a sampling frequency of 5 Hz. Were measured distances made for 10 football players (age, 22.5 ±2.9 years, height 174 ±7 cm. and weight 72.6 ±3.4 kg in the specific Yo-Yo Endurance Test level 1. The test ended when the players completed the first 10 levels of speed test (from 2.22 to 3.48 m·s-1. Four of the 10 participants took two simultaneously GPS, what allowed to value the reliability of the devices. In the validity study comparing the values obtained by the GPS with the actual values obtained by tape before performing the test. Statistical analysis were: coefficient of variation (1 – 17 %, standard error (2.3 – 136 m, standard error estimated, (5 – 11 % and means difference (-0.7 – 89.2 m. The results indicate that although the reliability and validity showed satisfactory results at moderate intensities, almost all levels and for the total distance, although the distance was overestimated

  13. Coupling long and short term decisions in the design of urban water supply infrastructure for added reliability and flexibility

    Marques, G.; Fraga, C. C. S.; Medellin-Azuara, J.


    The expansion and operation of urban water supply systems under growing demands, hydrologic uncertainty and water scarcity requires a strategic combination of supply sources for reliability, reduced costs and improved operational flexibility. The design and operation of such portfolio of water supply sources involves integration of long and short term planning to determine what and when to expand, and how much to use of each supply source accounting for interest rates, economies of scale and hydrologic variability. This research presents an integrated methodology coupling dynamic programming optimization with quadratic programming to optimize the expansion (long term) and operations (short term) of multiple water supply alternatives. Lagrange Multipliers produced by the short-term model provide a signal about the marginal opportunity cost of expansion to the long-term model, in an iterative procedure. A simulation model hosts the water supply infrastructure and hydrologic conditions. Results allow (a) identification of trade offs between cost and reliability of different expansion paths and water use decisions; (b) evaluation of water transfers between urban supply systems; and (c) evaluation of potential gains by reducing water system losses as a portfolio component. The latter is critical in several developing countries where water supply system losses are high and often neglected in favor of more system expansion.

  14. Regional electroencephalogram (EEG) alpha power and asymmetry in older adults: a study of short-term test-retest reliability.

    Mathewson, Karen J; Hashemi, Ali; Sheng, Bruce; Sekuler, Allison B; Bennett, Patrick J; Schmidt, Louis A


    Although regional alpha power and asymmetry measures have been widely used as indices of individual differences in emotional processing and affective style in younger populations, there have been relatively few studies that have examined these measures in older adults. Here, we examined the short-term test-retest reliability of resting regional alpha power (7.5-12.5 Hz) and asymmetry in a sample of 38 active, community-dwelling older adults (M age = 71.2, SD = 6.5 years). Resting electroencephalogram recordings were made before and after a perceptual computer task. Pearson and intra-class correlations indicated acceptable test-retest reliability for alpha power and asymmetry measures in all regions. Interestingly, alpha asymmetry appeared to be less affected by the task than was alpha power. Findings suggest that alpha asymmetry may reflect more enduring, "trait-like" characteristics, while alpha power may reflect more "state-like" processes in older adults.


    Julen Castellano


    Full Text Available The use of GPS technology for training and research purposes requires a study of the reliability, validity and accuracy of the data generated (Petersen et al., 2009. To date, studies have focused on devices with a logging rate of 1 Hz and 5 Hz (Coutts and Duffield, 2010; Duffield et al., 2010; Jennings et al., 2010; MacLeod et al., 2009; Petersen et al., 2009; Portas et al., 2010, although it seems that more frequent sampling can increase the accuracy of the information provided by these devices (Jennings et al., 2010; MacLeod et al., 2009, Portas et al., 2010. However, we are unaware of any study of the reliability and accuracy of GPS devices using a sampling frequency of 10 Hz. Thus, the aim of the present research was to determine the reliability and accuracy of GPS devices operating at a sampling frequency of 10 Hz, in relation here to sprints of 15 m and 30 m and using both video and photoelectric cells.Nine trained male athletes participated in the study. Each participant completed 7 and 6 linear runs of 15 m and 30 m, respectively (n = 117, with only one GPS device being used per participant. Each repetition required them to complete the route as quickly as possible, with 1 min recovery between sets. Distance was monitored through the use of GPS devices (MinimaxX v4.0, Catapult Innovations, Melbourne, Australia operating at the above mentioned sampling frequency of 10 Hz. In addition, all tests were filmed with a video camera operating at a sampling frequency of 25 frames. Data were collected during what were considered to be good GPS conditions in terms of the weather and satellite conditions (number of satellites = 10.0 ± 0.2 and 10.3 ± 0.4 for sprints of 15 m and 30 m, respectively.Distance was measured using a tape measure. Electronic timing gates (TAG- Heuer, CP 520 Training model, Switzerland were used to obtain a criterion sprint time accurate to 0.01 s, with gates being placed at the beginning and end of the route (Petersen et

  16. Simple and reliable procedure for PCR amplification of genomic DNA from yeast cells using short sequencing primers

    Haaning, J; Oxvig, C; Overgaard, Michael Toft;


    Yeast is widely used in molecular biology. Heterologous expression of recombinant proteins in yeast involves screening of a large number of recombinants. We present an easy and reliable procedure for amplifying genomic DNA from freshly grown cells of the methylotrophic yeast Pichia pastoris...... by means of PCR without any prior DNA purification steps. This method involves a simple boiling step of whole yeast cells in the presence of detergent, and subsequent amplification of genomic DNA using short sequencing primers in a polymerase chain reaction assay with a decreasing annealing temperature...

  17. Validity and reliability of the Short Form 36 Health Surveys (SF-36) among patients with spondyloarthritis in Singapore.

    Kwan, Yu Heng; Fong, Warren Weng Seng; Lui, Nai Lee; Yong, Si Ting; Cheung, Yin Bun; Malhotra, Rahul; Østbye, Truls; Thumboo, Julian


    The Short Form 36 Health Survey (SF-36) is a popular health-related quality of life (HrQoL) tool. However, few studies have assessed its psychometric properties in patients with spondyloarthritis (SpA). We therefore aimed to assess the reliability and validity of the SF-36 in patients with SpA in Singapore. Cross-sectional data from a registry of 196 SpA patients recruited from a dedicated tertiary referral clinic in Singapore from 2011 to 2014 was used. Analyses were guided by the COnsensus-based Standards for the selection of health Measurement INstruments framework. Internal consistency reliability was assessed using Cronbach's alpha. Construct validity was assessed through 33 a priori hypotheses by correlations of the eight subscales and two summary scores of SF-36 with other health outcomes. Known-group construct validity was assessed by comparison of the means of the subscales and summary scores of the SF-36 of SpA patients and the general population of Singapore using student's t tests. Among 196 patients (155 males (79.0 %), median (range) age: 36 (17-70), 166 Chinese (84.6 %)), SF-36 scales showed high internal consistency ranging from 0.88 to 0.90. Convergent construct validity was supported as shown by fulfillment of all hypotheses. Divergent construct validity was supported, as SF-36 MCS was not associated with PGA, pain and HAQ. Known-group construct validity showed SpA patients had lower scores of 3.8-12.5 when compared to the general population at p < 0.001. This study supports the SF-36 as a valid and reliable measure of HrQoL for use in patients with SpA at a single time point.

  18. Short (

    Telleman, Gerdien; den Hartog, Laurens


    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  19. Short (

    Telleman, Gerdien; den Hartog, Laurens


    Aim: This systematic review assessed the implant survival rate of short (<10 mm) dental implants installed in partially edentulous patients. A case report of a short implant in the posterior region have been added. Materials and methods: A search was conducted in the electronic databases of MEDLINE

  20. The Short International Physical Activity Questionnaire: cross-cultural adaptation, validation and reliability of the Hausa language version in Nigeria.

    Oyeyemi, Adewale L; Oyeyemi, Adetoyeje Y; Adegoke, Babatunde O; Oyetoke, Fatima O; Aliyu, Habeeb N; Aliyu, Salamatu U; Rufai, Adamu A


    Accurate assessment of physical activity is important in determining the risk for chronic diseases such as cardiovascular disease, stroke, type 2 diabetes, cancer and obesity. The absence of culturally relevant measures in indigenous languages could pose challenges to epidemiological studies on physical activity in developing countries. The purpose of this study was to translate and cross-culturally adapt the Short International Physical Activity Questionnaire (IPAQ-SF) to the Hausa language, and to evaluate the validity and reliability of the Hausa version of IPAQ-SF in Nigeria. The English IPAQ-SF was translated into the Hausa language, synthesized, back translated, and subsequently subjected to expert committee review and pre-testing. The final product (Hausa IPAQ-SF) was tested in a cross-sectional study for concurrent (correlation with the English version) and construct validity, and test-retest reliability in a sample of 102 apparently healthy adults. The Hausa IPAQ-SF has good concurrent validity with Spearman correlation coefficients (ρ) ranging from 0.78 for vigorous activity (Min Week-1) to 0.92 for total physical activity (Metabolic Equivalent of Task [MET]-Min Week-1), but poor construct validity, with cardiorespiratory fitness (ρ = 0.21, p = 0.01) and body mass index (ρ = 0.22, p = 0.04) significantly correlated with only moderate activity and sitting time (Min Week-1), respectively. Reliability was good for vigorous (ICC = 0.73, 95% C.I = 0.55-0.84) and total physical activity (ICC = 0.61, 95% C.I = 0.47-0.72), but fair for moderate activity (ICC = 0.33, 95% C.I = 0.12-0.51), and few meaningful differences were found in the gender and socioeconomic status specific analyses. The Hausa IPAQ-SF has acceptable concurrent validity and test-retest reliability for vigorous-intensity activity, walking, sitting and total physical activity, but demonstrated only fair construct validity for moderate and sitting activities. The Hausa IPAQ-SF can be used for

  1. Morpho-Functional 1H-MRI of the Lung in COPD: Short-Term Test-Retest Reliability.

    Bertram J Jobst

    Full Text Available Non-invasive end-points for interventional trials and tailored treatment regimes in chronic obstructive pulmonary disease (COPD for monitoring regionally different manifestations of lung disease instead of global assessment of lung function with spirometry would be valuable. Proton nuclear magnetic resonance imaging (1H-MRI allows for a radiation-free assessment of regional structure and function. The aim of this study was to evaluate the short-term reproducibility of a comprehensive morpho-functional lung MRI protocol in COPD.20 prospectively enrolled COPD patients (GOLD I-IV underwent 1H-MRI of the lung at 1.5T on two consecutive days, including sequences for morphology, 4D contrast-enhanced perfusion, and respiratory mechanics. Image quality and COPD-related morphological and functional changes were evaluated in consensus by three chest radiologists using a dedicated MRI-based visual scoring system. Test-retest reliability was calculated per each individual lung lobe for the extent of large airway (bronchiectasis, wall thickening, mucus plugging and small airway abnormalities (tree in bud, peripheral bronchiectasis, mucus plugging, consolidations, nodules, parenchymal defects and perfusion defects. The presence of tracheal narrowing, dystelectasis, pleural effusion, pulmonary trunk ectasia, right ventricular enlargement and, finally, motion patterns of diaphragma and chest wall were addressed.Median global scores [10(Q1:8.00;Q3:16.00 vs.11(Q1:6.00;Q3:15.00] as well as category subscores were similar between both timepoints, and kappa statistics indicated "almost perfect" global agreement (ĸ = 0.86, 95%CI = 0.81-0.91. Most subscores showed at least "substantial" agreement of MRI1 and MRI2 (ĸ = 0.64-1.00, whereas the agreement for the diagnosis of dystelectasis/effusion (ĸ = 0.42, 95%CI = 0.00-0.93 was "moderate" and of tracheal abnormalities (ĸ = 0.21, 95%CI = 0.00-0.75 "fair". Most MRI acquisitions showed at least diagnostic quality at

  2. Validity and reliability of the Very Short form of the Physical Self-Inventory among Turkish adolescents.

    Aşçi, F Hülya; Maïano, Christophe; Morin, Alexandre J S; Çağlar, Emine; Bilgili, Naile


    The study aimed to test the validity and reliability of the Very Short form of the Physical Self-Inventory (PSI-VS) among a sample of 635 Turkish adolescents. These adolescents have completed the 12 original items of the PSI-VS, plus a positively worded reformulation of the single reverse-keyed item of the physical attractiveness subscale. A series of confirmatory factor analyses was used to examine the psychometric properties of the original and modified versions of the PSI-VS. Findings revealed superior psychometric properties with the modified version than with the original set of items. The modified version was thus subsequently used to examine its factor structure invariance across sexes, age groups and sport practice involvement. Results not only report that this version was fully invariant across, but also that latent means were significantly different across sexes and sport practice involvement. In sum, the Turkish modified version of the PSI-VS presents acceptable psychometric properties and may be used to repeatedly and/or intensively assess participants' physical self-perceptions in the context of sport and exercise interventions.

  3. The Achievement of Therapeutic Objectives Scale: Interrater Reliability and Sensitivity to Change in Short-Term Dynamic Psychotherapy and Cognitive Therapy

    Valen, Jakob; Ryum, Truls; Svartberg, Martin; Stiles, Tore C.; McCullough, Leigh


    This study examined interrater reliability and sensitivity to change of the Achievement of Therapeutic Objectives Scale (ATOS; McCullough, Larsen, et al., 2003) in short-term dynamic psychotherapy (STDP) and cognitive therapy (CT). The ATOS is a process scale originally developed to assess patients' achievements of treatment objectives in STDP,…

  4. Reliability and validity of the short form of the child health questionnaire for parents (CHQ-PF28) in large random school based and general population samples

    H. Raat (Hein); A.M. Botterweck; J.M. Landgraf (Jeanne); W.C. Hoogeveen; M.L.E. Essink-Bot (Marie-Louise)


    textabstractSTUDY OBJECTIVES: This study assessed the feasibility, reliability, and validity of the 28 item short child health questionnaire parent form (CHQ-PF28) containing the same 13 scales, but only a subset of the items in the widely used 50 item CHQ-PF50. DESIGN: Questionnai

  5. The Spanish version of the Breastfeeding Self-Efficacy Scale-Short Form: reliability and validity assessment.

    Oliver-Roig, Antoni; d'Anglade-González, Marta-Luisa; García-García, Beatriz; Silva-Tubio, Jose-Ramón; Richart-Martínez, Miguel; Dennis, Cindy-Lee


    Only a minority of infants are exclusively breastfed for the recommended 6 months postpartum. Breastfeeding self-efficacy is a mother's confidence in her ability to breastfeed and is highly predictive of breastfeeding behaviors. The Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF) was developed among English-speaking mothers to measure breastfeeding self-efficacy. To translate the BSES-SF into Spanish and assess its psychometric properties. Methodological study. One public hospital in Orihuela, Spain. A convenience sample of 135 in-hospital breastfeeding women was recruited on their second day postpartum. The BSES-SF was translated into Spanish using forward translation, back-translation and pilot testing. Internal consistency, construct validity and predictive validity were assessed. A battery of self-report questionnaires was administered on the second day postpartum including: a questionnaire on sociodemographic variables and breastfeeding status, the translated BSES-SF, the Spanish adaptation of the General Self-Efficacy Scale and the Stress Management Self-Efficacy Scale. Also, data on breastfeeding status at three weeks postpartum were collected by telephone interviews. The Cronbach's alpha coefficient for internal consistency was 0.92. The translated BSES-SF presented a unidimensional structure with factor loadings of >0.30. In addition, demographic response patterns and correlations with self-efficacy scales provided further evidence of construct validity. In-hospital BSES-SF scores significantly predicted exclusive breastfeeding at 3 weeks postpartum. The results of this study indicate that the Spanish translation of the BSES-SF can be considered a valid and reliable measure of maternal breastfeeding self-efficacy in Spain. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Translation, cultural adaptation assessment, and both validity and reliability testing of the kidney disease quality of life - short form version 1.3 for use with Iranian patients

    Pakpour, Amir; Yekaninejad, Mirsaeed; Mølsted, Stig


    AIM: The aims of the study were to translate the Kidney Disease Quality of Life--Short Form version 1.3 (KDQOL-SF ver. 1.3) questionnaire into Iranian (Farsi), and to then assess it in terms of validity and reliability on Iranian patients. METHODS: The questionnaire was first translated into Farsi...... a larger group (212 patients with end-stage renal disease on haemodialysis). Afterwards, reliability was estimated by internal consistency, and validity was assessed using known group comparisons and constructs for the patient group as a whole. Finally, the factor structure of the questionnaire...

  7. An index-based short-form of the WISC-IV with accompanying analysis of the reliability and abnormality of differences.

    Crawford, John R; Anderson, Vicki; Rankin, Peter M; MacDonald, Jayne


    To develop an Index-based, seven subtest, short-form of the Wechsler intelligence scale for children fourth edition (WISC-IV) that offers the same comprehensive range of analytic methods available for the full-length version. Psychometric. The short-form Indexes had high reliability and criterion validity. Scores are expressed as Index scores and as percentiles. Methods are provided that allow setting of confidence limits on scores, and analysis of the reliability and abnormality of Index score differences. The use of the short-form is illustrated with a case example. A computer programme (that automates scoring and implements all the analytical methods) accompanies this paper and can be downloaded from the following web address: The short-form will be useful when pressure of time or client fatigue precludes use of a full-length WISC-IV. The accompanying computer programme scores and analyses an individual's performance on the short-form instantaneously and minimizes the chance of clerical error.

  8. Short-term test–retest reliability of resting state fMRI metrics in children with and without attention-deficit/hyperactivity disorder

    Krishna Somandepalli


    Full Text Available To date, only one study has examined test–retest reliability of resting state fMRI (R-fMRI in children, none in clinical developing groups. Here, we assessed short-term test–retest reliability in a sample of 46 children (11–17.9 years with attention-deficit/hyperactivity disorder (ADHD and 57 typically developing children (TDC. Our primary test–retest reliability measure was the intraclass correlation coefficient (ICC, quantified for a range of R-fMRI metrics. We aimed to (1 survey reliability within and across diagnostic groups, and (2 compare voxel-wise ICC between groups. We found moderate-to-high ICC across all children and within groups, with higher-order functional networks showing greater ICC. Nearly all R-fMRI metrics exhibited significantly higher ICC in TDC than in children with ADHD for one or more regions. In particular, posterior cingulate and ventral precuneus exhibited group differences in ICC across multiple measures. In the context of overall moderate-to-high test–retest reliability in children, regional differences in ICC related to diagnostic groups likely reflect the underlying pathophysiology for ADHD. Our currently limited understanding of the factors contributing to inter- and intra-subject variability in ADHD underscores the need for large initiatives aimed at examining their impact on test–retest reliability in both clinical and developing populations.

  9. Translation, cross-cultural adaptation, reliability and discriminative validity of the Danish version of the short questionnaire to assess health-enhancing physical activity (SQUASH)

    Jacobsen, Julie Sandell; Sørensen, Lotte; Mikkelsen, Lone Ramer;


    Background: There is abundant evidence that physical activity has a fundamental role in the prevention and treatment of chronic disease. Questionnaires are simple and inexpensive to apply to measure physical activity. Purpose / Aim of Study: Translate and cross-cultural adapt the short questionna......Background: There is abundant evidence that physical activity has a fundamental role in the prevention and treatment of chronic disease. Questionnaires are simple and inexpensive to apply to measure physical activity. Purpose / Aim of Study: Translate and cross-cultural adapt the short...... 47.2 � 12.6 years and mean period 37.1 � 14.9 days between test and retest. The relative reliability was assessed with intraclass correlation coefficient (ICC) and the absolute reliability with standard error of measurement (SEM) and smallest detectable change (SDC). The discriminative validity...

  10. Validity and reliability of the Arabic short version of the child oral health-related quality of life questionnaire (CPQ 11-14) in Medina, Saudi Arabia.

    Bhayat, A; Ali, M A M


    The Arabic version of the Child Perception Questionnaire for assessing oral health-related quality of life in 11-14 year olds (CPQ 11-14) has been validated previously. This study tested the validity and reliability of a short version of the Arabic CPQ 11-14 in the general population of Medina, Saudi Arabia. A total of 268 schoolchildren completed the questionnaire and were examined to determine the prevalence of caries and malocclusion. The mean total score was 8.53 (SD 8.18), and 7% of children scored zero. There was a significant association between malocclusion and oral symptoms and between DMFT score and functional limitations. The test-retest reliability (0.78) and Cronbach alpha (0.82) were excellent. The construct validity was acceptable for oral health (ρ = 0.37) and overall well-being (ρ = 0.40). The Arabic version of the short form CPQ 11-14 was reliable and valid for this general population of children.

  11. The Behavior Problems Inventory-Short Form for individuals with intellectual disabilities: Part II: reliability and validity

    Rojahn, J.; Rowe, E.W.; Sharber, A.C.; Hastings, R.P.; Matson, J.L.; Didden, H.C.M.; Kroes, D.B.H.; Dumont, E.L.M.


    Background The Behavior Problems Inventory-01 (BPI-01) is an informant-based behaviour rating instrument for intellectual disabilities (ID) with 49 items and three sub-scales: Self-injurious Behavior, Stereotyped Behavior and Aggressive/Destructive Behavior. The Behavior Problems Inventory-Short For

  12. Balancing the Need for Reliability and Time Efficiency: Short Forms of the Wechsler Adult Intelligence Scale-III

    Jeyakumar, Sharon L. E.; Warriner, Erin M.; Raval, Vaishali V.; Ahmad, Saadia A.


    Tables permitting the conversion of short-form composite scores to full-scale IQ estimates have been published for previous editions of the Wechsler Adult Intelligence Scale (WAIS). Equivalent tables are now needed for selected subtests of the WAIS-III. This article used Tellegen and Briggs's formulae to convert the sum of scaled scores for four…

  13. Test-Retest Reliability of a Short Form of the Children’s Social Desirability Scale for Nutrition and Health-Related Research

    Miller, Patricia H.; Baxter, Suzanne D.; Hitchcock, David B.; Royer, Julie A.; Smith, Albert F.; Guinn, Caroline H.


    Objective To examine test-retest reliability and internal consistency of the Children’s Social Desirability Short (S-CSD) scale, consisting of 14 items from the Children’s Social Desirability scale. Methods The previously validated S-CSD scale was classroom administered to 97 fourth-grade children (80% African American, 76% low socioeconomic status) in 2 sessions a month apart. Each classroom administration lasted approximately 5 minutes. Results The S-CSD scale showed acceptable levels of test-retest reliability (0.70) and internal consistency (0.82 and 0.85 for the first and second administrations, respectively). Reliability was adequate within subgroups of gender, socioeconomic status, academic achievement, and body mass index percentile. Levels of social desirability did not differ across subgroups. Conclusions and Implications Social desirability bias is a potential source of systematic response error in children’s self-report assessments of nutrition and health-related behaviors. The S-CSD scale may be used with diverse groups of children to reliably and efficiently assess social desirability bias. PMID:24418615

  14. Test-retest reliability of a short form of the children's social desirability scale for nutrition and health-related research.

    Miller, Patricia H; Baxter, Suzanne D; Hitchcock, David B; Royer, Julie A; Smith, Albert F; Guinn, Caroline H


    To examine test-retest reliability and internal consistency of the Children's Social Desirability Short (CSD-S) scale, consisting of 14 items from the Children's Social Desirability scale. The previously validated CSD-S scale was classroom administered to 97 fourth-grade children (80% African American; 76% low socioeconomic status) in 2 sessions a month apart. Each classroom administration lasted approximately 5 minutes. The CSD-S scale showed acceptable levels of test-retest reliability (0.70) and internal consistency (.82 and .85 for the first and second administrations, respectively). Reliability was adequate within subgroups of gender, socioeconomic status, academic achievement, and body mass index percentile. Levels of social desirability did not differ across subgroups. Social desirability bias is a potential source of systematic response error in children's self-report assessments of nutrition and health-related behaviors. The CSD-S scale may be used with diverse groups of children to reliably and efficiently assess social desirability bias. Copyright © 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  15. Reliability of the Danish version of the short questionnaire to assess health-enhancing physical activity (SQUASH)

    Jacobsen, Julie Sandell; Sørensen, Lotte; Mikkelsen, Lone Ramer


    was evaluated in 22 patients with hip dysplasia, mean age 34.8 � 7.9 years, who were compared with 26 healthy individuals matched on age. Findings / Results: For the total activity score ICC was 0.71 (95% CI: 0.54; 0.82), SEM was 2351 MET x min/week (25% of the grand mean) and the SDC was 6517 MET x min....../week (70% of the grand mean). There was no significant difference between healthy adults and patients with hip dysplasia in total activity score but a significant difference in time spent on activities of high intensity. Conclusions: Relative raliability was acceptable and indicates that the Danish...... reliability was poor and SQUASH is not considered suitable for measuring physical activity on an individual level. SQUASH was unable to discriminate between healthy individuals and patients with hip dysplasia with respect to total activity score, but was able to discriminate on time spent on activities...

  16. Reliability-based automatic repeat request for short code modulation visual evoked potentials in brain computer interfaces.

    Sato, Jun-Ichi; Washizawa, Yoshikazu


    We propose two methods to improve code modulation visual evoked potential brain computer interfaces (cVEP BCIs). Most of BCIs average brain signals from several trials in order to improve the classification performance. The number of averaging defines the trade-off between input speed and accuracy, and the optimal averaging number depends on individual, signal acquisition system, and so forth. Firstly, we propose a novel dynamic method to estimate the averaging number for cVEP BCIs. The proposed method is based on the automatic repeat request (ARQ) that is used in communication systems. The existing cVEP BCIs employ rather longer code, such as 63-bit M-sequence. The code length also defines the trade-off between input speed and accuracy. Since the reliability of the proposed BCI can be controlled by the proposed ARQ method, we introduce shorter codes, 32-bit M-sequence and the Kasami-sequence. Thanks to combine the dynamic averaging number estimation method and the shorter codes, the proposed system exhibited higher information transfer rate compared to existing cVEP BCIs.

  17. Reliability and Validity of the Medical Outcomes Study Short Form-12 Version 2 (SF-12v2 in Adults with Non-Cancer Pain

    Corey J. Hayes


    Full Text Available Limited evidence exists on how non-cancer pain (NCP affects an individual’s health-related quality of life (HRQoL. This study aimed to validate the Medical Outcomes Study Short Form-12 Version 2 (SF-12v2, a generic measure of HRQoL, in a NCP cohort using the Medical Expenditure Panel Survey Longitudinal Files. The SF Mental Component Summary (MCS12 and SF Physical Component Summary (PCS12 were tested for reliability (internal consistency and test-retest reliability and validity (construct: convergent and discriminant; criterion: concurrent and predictive. A total of 15,716 patients with NCP were included in the final analysis. The MCS12 and PCS12 demonstrated high internal consistency (Cronbach’s alpha and Mosier’s alpha > 0.8, and moderate and high test-retest reliability, respectively (MCS12 intraclass correlation coefficient (ICC: 0.64; PCS12 ICC: 0.73. Both scales were significantly associated with a number of chronic conditions (p < 0.05. The PCS12 was strongly correlated with perceived health (r = 0.52 but weakly correlated with perceived mental health (r = 0.25. The MCS12 was moderately correlated with perceived mental health (r = 0.42 and perceived health (r = 0.33. Increasing PCS12 and MCS12 scores were significantly associated with lower odds of reporting future physical and cognitive limitations (PCS12: OR = 0.90 95%CI: 0.89–0.90, MCS12: OR = 0.94 95%CI: 0.93–0.94. In summary, the SF-12v2 is a reliable and valid measure of HRQoL for patients with NCP.

  18. Short- and long-term reliability of adult recall of vegetarian dietary patterns in the Adventist Health Study-2 (AHS-2).

    Teixeira Martins, Marcia C; Jaceldo-Siegl, Karen; Fan, Jing; Singh, Pramil; Fraser, Gary E


    Past dietary patterns may be more important than recent dietary patterns in the aetiology of chronic diseases because of the long latency in their development. We developed an instrument to recall vegetarian dietary patterns during the lifetime and examined its reliability of recall over 5·3 and 32·6 years on average. The short-term/5-year recall ability study (5-RAS) was done using 24 690 participants from the cohort of the Adventist Health Study-2 (mean age 62·2 years). The long-term/33-year recall ability study (33-RAS) included an overlap population of 1721 individuals who joined the Adventist Health Study-1 and Adventist Health Study-2 (mean age 72·5 years). Spearman correlation coefficients for recall of vegetarian status were 0·78 and 0·72 for the 5-RAS and 33-RAS, respectively, when compared with 'reference' data. For both time periods sensitivity and positive predictive values were highest for the lacto-ovo-vegetarian and non-vegetarian patterns (vegans, lacto-ovo-vegetarians, pesco-vegetarians, semi-vegetarians and non-vegetarians). In the 5-RAS analyses, male, non-black, younger, and more educated participants, lifetime Adventists, and those with more stability of consumption of animal products generally showed higher recall ability. Somewhat similar tendencies were shown for the 33-RAS analyses. Our findings show that the instrument has higher reliability for recalled lacto-ovo-vegetarian and non-vegetarian than for vegan, semi- and pesco-vegetarian dietary patterns in both short- and long-term recalls. This is in part because these last dietary patterns were greatly contaminated by recalls that correctly would have belonged in the adjoining category that consumed more animal products.

  19. Reliability and reproducibility of quantitative assessment of left ventricular function and volumes with 3-slice segmentation of cine steady-state free precession short axis images

    Nguyen, Christopher, E-mail: [School of Medicine, University of California, Irvine, Orange, CA (United States); Kuoy, Edward, E-mail: [School of Medicine, University of California, Irvine, Orange, CA (United States); Ruehm, Stefan, E-mail: [Diagnostic Cardiovascular Imaging, University of California, Los Angeles (United States); Krishnam, Mayil, E-mail: [Cardiovascular and Thoracic Imaging, Radiological Sciences, University of California, Irvine, Orange, CA (United States)


    Highlights: • Quantitative LV assessment in CMR requires contour tracing of multiple SA images. • Conventional multi-slice method for LV assessment is tedious and time-consuming. • 3-slice segmentation is comparable to multi-slice method in determining LVEF. • 3-slice method is reliable and reproducible in determining LV volumes and mass. • 3-slice method reduces post-processing time compared to multi-slice method. - Abstract: Objectives: Quantitative assessment of left ventricular (LV) functional parameters in cardiac MR requires time-consuming contour tracing across multiple short axis images. This study assesses global LV functional parameters using 3-slice segmentation on steady state free precision (SSFP) cine short axis images and compares the results with conventional multi-slice segmentation of LV. Methods: Data were collected from 61 patients who underwent cardiac MRI for various clinical indications. Semi-automated cardiac MR software was used to trace LV contours both at multiple slices from base to apex as well as just 3 slices (base, mid, and apical) by two readers. Left ventricular ejection fraction (LVEF), LV volumes, and LV mass were calculated using both methods. Results: Bland–Altman plot revealed narrow limits of agreement (−4.4% to 5.1%) between LVEF obtained by the two methods. Bland–Altman analysis showed slightly wider limits of agreement between end-diastolic volumes (−5.0 to 12.0%; −3.9 to 8.5 ml/m{sup 2}), end-systolic volumes (−10.9 to 14.7%; −4.1 to 6.5 ml/m{sup 2}), and LV mass (−5.2 to 12.7%; −4.8 to 10.2 g/m{sup 2}) obtained by the two methods. There was a small mean difference between LV volumes and LV mass obtained using multi-slice and 3-slice segmentation. No statistically significant difference existed between the LV parameters obtained by the two readers using 3-slice segmentation (p > 0.05). Multi-slice assessment required approximately 15 min per study while 3-slice assessment required less than 5

  20. The Zarit Caregiver Burden Interview Short Form (ZBI-12 in spouses of Veterans with Chronic Spinal Cord Injury, Validity and Reliability of the Persian Version

    Mohammad T. Rajabi Mashhadi


    Full Text Available Background:  To test the psychometric properties of the Persian version of Zarit Burden Interview (ZBI-12 in the Iranian opulation.  Methods: After translating and cultural adaptation of the questionnaire into Persian, 100 caregiver spouses of Iran-Iraq war (1980-88 veterans with chronic spinal cord injury who live in the city of Mashhad, Iran, invited to participate in the study. The Persian version of ZBI-12 accompanied with the Persian SF-36 was completed by the caregivers to test validity of the Persian ZBI-12.A Pearson`s correlation coefficient was calculated for validity testing.In order to assess reliability of the Persian ZBI-12, we administered the ZBI-12 randomly in 48 caregiver spouses again 3 days later. Results:  Generally, the internal consistency of the questionnaire was found to be strong (Cronbach’s alpha 0.77. Intercorrelationmatrix between the different domains of ZBI-12 at test-retest was 0.78. The results revealed that majority of questions the Persian ZBI_12 have a significant correlation to each other. In terms of validity, our results showed that there is significant correlations between some domains of the Persian version the Short Form Health Survey -36 with the Persian Zarit Burden Interview such as Q1 with Role Physical (P=0.03,General Health (P=0.034,Social Functional (0.037, Mental Health (0.023 and Q3 with Physical Function (P=0.001,Viltality (0.002, Socil Function (0.001.  Conclusions:  Our findings suggest that the Zarit Burden Interview Persian version is both a valid and reliable instrument for measuring the burden of caregivers of individuals with chronic spinal cord injury.

  1. The Zarit Caregiver Burden Interview Short Form (ZBI-12 in spouses of Veterans with Chronic Spinal Cord Injury, Validity and Reliability of the Persian Version

    Mohammad T. Rajabi Mashhadi


    Full Text Available Background:  To test the psychometric properties of the Persian version of Zarit Burden Interview (ZBI-12 in the Iranian opulation.  Methods: After translating and cultural adaptation of the questionnaire into Persian, 100 caregiver spouses of Iran-Iraq war (1980-88 veterans with chronic spinal cord injury who live in the city of Mashhad, Iran, invited to participate in the study. The Persian version of ZBI-12 accompanied with the Persian SF-36 was completed by the caregivers to test validity of the Persian ZBI-12.A Pearson`s correlation coefficient was calculated for validity testing.In order to assess reliability of the Persian ZBI-12, we administered the ZBI-12 randomly in 48 caregiver spouses again 3 days later. Results:  Generally, the internal consistency of the questionnaire was found to be strong (Cronbach’s alpha 0.77. Intercorrelationmatrix between the different domains of ZBI-12 at test-retest was 0.78. The results revealed that majority of questions the Persian ZBI_12 have a significant correlation to each other. In terms of validity, our results showed that there is significant correlations between some domains of the Persian version the Short Form Health Survey -36 with the Persian Zarit Burden Interview such as Q1 with Role Physical (P=0.03,General Health (P=0.034,Social Functional (0.037, Mental Health (0.023 and Q3 with Physical Function (P=0.001,Viltality (0.002, Socil Function (0.001.  Conclusions:  Our findings suggest that the Zarit Burden Interview Persian version is both a valid and reliable instrument for measuring the burden of caregivers of individuals with chronic spinal cord injury.

  2. Relationship Between Agility Tests and Short Sprints: Reliability and Smallest Worthwhile Difference in National Collegiate Athletic Association Division-I Football Players.

    Mann, J Bryan; Ivey, Pat A; Mayhew, Jerry L; Schumacher, Richard M; Brechue, William F


    The Pro-Agility test (I-Test) and 3-cone drill (3-CD) are widely used in football to assess quickness in change of direction. Likewise, the 10-yard (yd) sprint, a test of sprint acceleration, is gaining popularity for testing physical competency in football players. Despite their frequent use, little information exists on the relationship between agility and sprint tests as well the reliability and degree of change necessary to indicate meaningful improvement resulting from training. The purpose of this study was to determine the reliability and smallest worthwhile difference (SWD) of the I-Test and 3-CD and the relationship of sprint acceleration to their performance. Division-I football players (n = 64, age = 20.5 ± 1.2 years, height = 185.2 ± 6.1 cm, body mass = 107.8 ± 20.7 kg) performed duplicate trials in each test during 2 separate weeks at the conclusion of a winter conditioning period. The better time of the 2 trials for each week was used for comparison. The 10-yd sprint was timed electronically, whereas the I-Test and 3-CD were hand timed by experienced testers. Each trial was performed on an indoor synthetic turf, with players wearing multicleated turf shoes. There was no significant difference (p > 0.06) between test weeks for the I-Test (4.53 ± 0.35 vs. 4.54 ± 0.31 seconds), 3-CD (7.45 ± 0.06 vs. 7.49 ± 0.06 seconds), or 10-yd sprint (1.85 ± 0.12 vs. 1.84 ± 0.12 seconds). The intraclass correlation coefficients (ICC) for 3-CD (ICC = 0.962) and 10-yd sprint (ICC = 0.974) were slightly higher than for the I-Test (ICC = 0.914). These values lead to acceptable levels of the coefficient of variation for each test (1.2, 1.2, and 1.9%, respectively). The SWD% indicated that a meaningful improvement due to training would require players to decrease their times by 6.6% for I-Test, 3.7% for 3-CD, and 3.8% for 10-yd sprint. Performance in agility and short sprint tests are highly related and reliable in college football players, providing quantifiable

  3. Reliability and Validity of the Young Parenting Inventory-Short Form in Chinese People%Young养育问卷中文简版的修订

    杨清艳; 陈楠; 郑军然; 李东; 张丽霞


    Objective:To revise the Young Parenting Inventory ( YPI ) into Chinese short version and examine its reliability and validity in Chinese people.Methods:The YPI was authorized to translate into Chinese version,translation and back-translation,expert assessment were used to work out the Chinese version of Young Parenting Inventory.Totally 233 adult healthy volunteers were selected by convenience sampling and were assessed with the YPI and YSQ-SF,and these subjects were assessed to select items and to perform the exploratory factor analysis to work out the formal YPI-SF.Criterion validity was as-sessed by comparing with YSQ-SF.The retest reliability of YPI-SF was tested in 110 subjects 4 weeks later.Results:Exploratory factor analysis revealed that YPI-SF was consisted of 17 factors explaining 74.1%of the total variance.YPI-SF was finally decided to be consist of 45 items.Except one subscale, both total scale and other subscales of YPI-SF were positively correlated with of YSQ-SF( r=0.15~0.36,P<0.05).The Cronbach's αof YPI-SF total scale was 0.86,and those for YPI-SF subscales were 0.51~0.85.The test-retest reliability for total scale was 0.72,and those for subscales were 0.40~0.68.Conclusion:The Chinese version of Young Parenting Inventory-Short Form has good reliability and validity in normal population,which can be used to screen people's early maladaptive schema.%目的:探讨简化后的Young养育问卷( Young Parenting Inventory-Short Form,YPI-SF)在中国正常人群中的信效度。方法:经YPI版权所属机构授权,按照跨文化修订法对YPI进行修订,YPI中文版包含72个条目,17个因子。采用方便取样入组233名成年健康人完成YPI中文版和Young图式问卷-简版( YSQ-SF)。分析YPI内部一致性,进行项目分析筛选和探索性因素分析,形成Young养育问卷中文简版( Young Parenting Inventory-Short Form,YPI-SF)。使用YSQ-SF作为效标

  4. Short trains of intra-epidermal electrical stimulation to elicit reliable behavioral and electrophysiological responses to the selective activation of nociceptors in humans.

    Mouraux, André; Marot, Emilie; Legrain, Valéry


    Currently, the study of nociception in humans relies mainly on thermal stimulation of heat-sensitive nociceptive afferents. To circumvent some limitations of thermal stimulation, it was proposed that intra-epidermal electrical stimulation (IES) could be used as an alternative method to activate nociceptors selectively. The selectivity of IES relies on the fact that it can generate a very focal electrical current and, thereby, activate nociceptive free nerve endings located in the epidermis without concomitantly activating non-nociceptive mechanoreceptors located more deeply in the dermis. However, an important limitation of IES is that it is selective for nociceptors only when very low current intensities are used. At these intensities, the stimulus generates a very weak percept, and the signal-to-noise ratio of the elicited evoked potentials (EPs) is very low. To circumvent this limitation, it was proposed that the strength of the nociceptive afferent volley could be increased through temporal summation, using short trains of repeated IES. Here, we characterized the intensity of perception and EPs elicited by trains of 2, 3 and 4 IES delivered using a 5-ms inter-stimulus interval. We found that both the intensity of perception and the magnitude of EPs significantly increased with the number of pulses. In contrast, the latency of the elicited EPs was not affected by the number of pulses, indicating that temporal summation did not affect the type of activated fibers and, therefore, that trains of IES can be used to increase the reliability of stimulus-evoked responses while still preserving its selectivity for nociceptors.

  5. Experimental and theoretical analyses of gate oxide and junction reliability for 4H-SiC MOSFET under short-circuit operation

    An, Junjie; Namai, Masaki; Iwamuro, Noriyuki


    In this study, the experimental evaluation and numerical analysis of the short-circuit capability of the 1200 V SiC MOSFET with a thin gate oxide layer were carried out. Two different failures, including the gate oxide breakdown and thermal runaway of the device caused by the high gate electric field and elevated lattice temperature, were initially investigated and their critical temperature points for two failure modes were accurately extrapolated by solving the thermal diffusion equation; the obtained results are in good agreement with simulation results. It was confirmed that short-circuit robustness depends not only on thermal properties of the material but also on dimensional parameters of the device and that the heat is the dominant factor that causes device failure during short-circuit transient.

  6. Multiplex PCR for 17 Y-Chromosome Specific Short Tandem Repeats (STR to Enhance the Reliability of Fetal Sex Determination in Maternal Plasma

    Fang Zheng


    Full Text Available The aim of the study was to demonstrate the influence of target gene and amplification product length on the performance of fetal gender determination systems using maternal plasma. A total of 40 pairs of plasma DNA samples from pregnant women and genomic DNA samples from maternal blood, amniotic fluid and paternal blood were isolated for gender determination by amplification of the amelogenin gene and 17 Y-chromosome STR loci, using three different commercial kits. The gender of the fetuses was confirmed by cytogenetic analysis or phenotype at birth. Both the AmpFℓSTR-Identifiler amplification kit and the Mini-STR Amplification kit for amelogenin gene detection were reliable in determining fetal gender (92.0% and 96.0%, respectively, but false negatives were present in both systems. AmpFℓSTR-Yfiler was found to be fully reliable as it amplified Y-STR in all cases of pregnancies with male fetuses and thus was 100% correct in determining fetal gender. The results demonstrated that multiple fluorescent PCR for 17 Y-STR loci was more reliable than AMELY gene testing in fetal sex determination with maternal plasma. We also found that the shorter amplification products could improve the performance of fetal gender determination systems.

  7. Multiplex PCR for 17 Y-chromosome Specific Short Tandem Repeats (STR) to enhance the reliability of fetal sex determination in maternal plasma.

    Rong, Yuan; Gao, Jiajia; Jiang, Xinqiang; Zheng, Fang


    The aim of the study was to demonstrate the influence of target gene and amplification product length on the performance of fetal gender determination systems using maternal plasma. A total of 40 pairs of plasma DNA samples from pregnant women and genomic DNA samples from maternal blood, amniotic fluid and paternal blood were isolated for gender determination by amplification of the amelogenin gene and 17 Y-chromosome STR loci, using three different commercial kits. The gender of the fetuses was confirmed by cytogenetic analysis or phenotype at birth. Both the AmpFℓSTR-Identifiler amplification kit and the Mini-STR Amplification kit for amelogenin gene detection were reliable in determining fetal gender (92.0% and 96.0%, respectively), but false negatives were present in both systems. AmpFℓSTR-Yfiler was found to be fully reliable as it amplified Y-STR in all cases of pregnancies with male fetuses and thus was 100% correct in determining fetal gender. The results demonstrated that multiple fluorescent PCR for 17 Y-STR loci was more reliable than AMELY gene testing in fetal sex determination with maternal plasma. We also found that the shorter amplification products could improve the performance of fetal gender determination systems.

  8. Validity, reliability, and responsiveness of a new short Visual Simplified Respiratory Questionnaire (VSRQ© for health-related quality of life assessment in chronic obstructive pulmonary disease

    T Perez


    Full Text Available T Perez1, B Arnould2, J-M Grosbois3, V Bosch2, I Guillemin2, M-L Bravo4, M Brun4, A-B Tonnel1 on behalf of TIPHON Study Group1Centre Hospitalier Régional Universitaire (CHRU, Lille, France; 2Mapi Values, Lyon, France; 3Service de Pneumologie, Centre Hospitalier de Béthune, Béthune, France; 4Boehringer Ingelheim France, Reims Cédex, FranceAbstract: The Visual Simplified Respiratory Questionnaire (VSRQ was designed to assess health-related quality of life (HRQoL in patients with chronic obstructive pulmonary disease (COPD. It contains eight items: dyspnea, anxiety, depressed mood, sleep, energy, daily activities, social activities and sexual life. Psychometric properties were assessed during a clinical trial that evaluated the impact of tiotropium on HRQoL of COPD patients. These included the determination of structure, internal consistency reliability, concurrent validity with the St George’s Respiratory Questionnaire (SGRQ, test – retest reliability, clinical validity and responsiveness to change over two weeks. Minimal important difference (MID was calculated; cumulative response curves (CRC were based on the dyspnea item. Psychometric analyses showed that VSRQ structure was unidimensional. The questionnaire demonstrated good internal consistency reliability (Cronbach’s alpha = 0.84, good concurrent validity with SGRQ (Spearman = −0.70 and clinical validity, good test-retest reproducibility (ICC = 0.77, and satisfactory responsiveness (standardized response mean = 0.57; Guyatt’s statistic = 0.63. MID was 3.4; CRC median value of the ‘minimally improved’ patients was 3.5. In conclusion, VSRQ brevity and satisfactory psychometric properties make it a good candidate for large studies to assess HRQoL in COPD patients. Further validation is needed to extend its use in clinical practice.Keywords: chronic obstructive pulmonary disease, VSRQ, SGRQ, health-related quality of life, minimal important difference

  9. The Short Health Scale: a valid and reliable measure of health related quality of life in English speaking inflammatory bowel disease patients.

    McDermott, Edel


    Health related quality of life in inflammatory bowel disease is influenced both by disease activity as well as by the psychosocial characteristics of the individual patient. The Short Health Scale (SHS) is a four-part visual analogue scale questionnaire using open-ended questions that are designed to assess the impact of inflammatory bowel disease on a health related quality of life. The four dimensions include bowel symptoms, activities of daily life, worry and general wellbeing. It has previously been validated in Swedish and Norwegian speaking patients.

  10. Validity, reliability, and assessment sensitivity of the Japanese version of the short-form McGill pain questionnaire 2 in Japanese patients with neuropathic and non-neuropathic pain.

    Maruo, Tomoyuki; Nakae, Aya; Maeda, Lynn; Shi, Kenrin; Takahashi, Kayoko; Morris, Shayne; Hosomi, Koichi; Kanatani, Hiroshi; Matsuzaki, Taiga; Saitoh, Youichi


    The objective of this study was to define the validity, reliability, and assessment sensitivity of the Japanese version of the Short-Form McGill Pain Questionnaire 2 (SF-MPQ-2-J). This is a cross-sectional study. The original SF-MPQ-2 was translated into Japanese to create the SF-MPQ-2-J, and the cross-cultural equivalence of assessment tool for Japanese patients was validated. The reliability of the SF-MPQ-2-J was assessed using internal consistency, reliability coefficients (Cronbach's α), and reproducibility coefficients (intraclass correlation coefficient) obtained using 234 patients with chronic pain. SF-MPQ-2-J validity was assessed based on associations identified between total and subscale scores compared with other assessment methods. A confirmatory factor analysis (CFA) was also performed to test the theoretical structure of the SF-MPQ-2-J. The internal consistencies calculated included continuous pain, α=0.893; intermittent pain, α=0.875; predominantly neuropathic pain, α=0.917; affective descriptors, α=0.857; and total score, α=0.907. The reproducibility coefficients calculated included continuous pain, ρ=0.81; intermittent pain, ρ=0.78; predominantly neuropathic pain, ρ=0.85; affective descriptors, ρ=0.75; and total score, ρ=0.83. The CFA showed that the model fit of the readily interpretable subscales was acceptable, and the goodness of fit index value was 0.917. In addition, the mean predominantly neuropathic pain subscale score was found to be significantly higher for patients with neuropathic pain vs non-neuropathic pain. These findings suggest that the reliability and validity of the SF-MPQ-2-J are excellent, and the SF-MPQ-2-J represents a cross-cultural equivalent to SF-MPQ-2. Consequently, the latter is suitable for research and clinical use, and for discriminating neuropathic pain from non-neuropathic pain. Wiley Periodicals, Inc.

  11. The Satz-Mogel short form of the Wechsler Adult Intelligence Scale--revised: effects of global mental status and age on test-retest reliability.

    McPherson, S; Buckwalter, G J; Tingus, K; Betz, B; Back, C


    Abbreviated versions of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) have been developed as time saving devices that provide accurate estimates of overall level of general intellectual functioning while decreasing test administration time. The Satz-Mogel short form of the WAIS-R has received substantial attention in the literature as an accurate measure of intellectual functions when compared with the Full WAIS-R. However, most studies comparing the Satz-Mogel version to the Full WAIS-R have only provided correlational analyses. Our study was an attempt to apply a more rigorous statistical methodology in determining if the Full WAIS-R and abbreviated versions are equivalent. We explored the impact of level of global mental status and age on the Satz-Mogel version. Although the two forms of the test correlated highly, repeated measures design indicated significant differences between Satz-Mogel and Full WAIS-R when participants were divided into groups based on level of global impairment and age. Our results suggest that the Satz-Mogel version of the test may not be equivalent to the full WAIS-R and is likely to misrepresent a patient's level of intellectual functioning, particularly for patients with progressive degenerative conditions. The implications of applying Satz-Mogel scoring to the Wechsler Adult Intelligence Scale-III (WAIS-III) are discussed.

  12. MEMS reliability

    Hartzell, Allyson L; Shea, Herbert R


    This book focuses on the reliability and manufacturability of MEMS at a fundamental level. It demonstrates how to design MEMs for reliability and provides detailed information on the different types of failure modes and how to avoid them.

  13. Software reliability

    Bendell, A


    Software Reliability reviews some fundamental issues of software reliability as well as the techniques, models, and metrics used to predict the reliability of software. Topics covered include fault avoidance, fault removal, and fault tolerance, along with statistical methods for the objective assessment of predictive accuracy. Development cost models and life-cycle cost models are also discussed. This book is divided into eight sections and begins with a chapter on adaptive modeling used to predict software reliability, followed by a discussion on failure rate in software reliability growth mo

  14. 改良SPES量表对帕金森病评价的信度和效度研究%Study on the validity and reliability of the modified Short Parkinson's Evaluation Scale

    吴卓华; 邵明; 林杰; 谭红愉; 吴宜娟; 李焕敏; 刘磊


    Objective To evaluate the reliability and validity of the modified Short Parkinson's Evaluation Scale (SPES). Methods 60 patients with Parkinson's Disease (PD) were assessed with SPES, unified Parkinson's Disease Rating Scale(UPDRS) and Hoehn and Yahr(H&Y) Scale at the same time. The latter two scales were evaluated to the validity of SPES. 30 cases were examined twice by different PD's doctors to assess the inter-rater reliability of SPES. Results The reproducibility was same for all subseales between SPES and UPDRS,and both scales revealed similar correlation with H&Y scale of disease severity. More over, the mean time to complete measures differed significantly (P<0.001). Conclusion The SPES is a short, reliable, and valid scale that can adequately be measured in clinical research and follow-up.%目的 改良SPES量表是一个新的评价帕金森病实用方法,本文对改良SPES评价结果作信度和效度研究.方法 60例帕金森病患者同时使用改良SPES,UPDRS和H&Y指数进行评定,以后两种量表对改良SPES的有效性进行相关分析.筛选出无"开-关"现象的30例使用改良SPES和UPDRS先后评定2次,以评估其内部重复性.结果 改良SPES与UPDRS各对应亚项的内部相关系数一致.能反映疾病的严重程度,有效性强.且改良SPES的评价时间明显短于UPDRS(P<0.001).结论 改良SPES是一个简短的、可信的、有效的评价方法,值得充分应用.

  15. Hawaii Electric System Reliability

    Loose, Verne William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silva Monroy, Cesar Augusto [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  16. Hawaii electric system reliability.

    Silva Monroy, Cesar Augusto; Loose, Verne William


    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  17. Reliability Engineering

    Lazzaroni, Massimo


    This book gives a practical guide for designers and users in Information and Communication Technology context. In particular, in the first Section, the definition of the fundamental terms according to the international standards are given. Then, some theoretical concepts and reliability models are presented in Chapters 2 and 3: the aim is to evaluate performance for components and systems and reliability growth. Chapter 4, by introducing the laboratory tests, puts in evidence the reliability concept from the experimental point of view. In ICT context, the failure rate for a given system can be

  18. Reprodutibilidade da curva força-tempo do estilo "Crawl" em protocolo de curta duração Reliability of front-Crawl's force-time curve in a short duration protocol

    Augusto Carvalho Barbosa


    trial. The paired student-t test was used to verify differences between trials for each biomechanical parameter. The significance level adopted was 5%. Relative reliability was tested by Pearson correlation coefficient and the consistency between trials by means of intraclass coefficient (CCI. The coefficient of variation was used to verify the absolute reliability. No significant differences between the trials to any biomechanical parameter were found. High CCI values and low CV values revealed the high internal consistency of the analyzed variables. It can be concluded that the biomechanical parameters regarding the tethered swimming are reliable in short duration protocols and may be used by coaches and athletes for monitoring training.

  19. Reliability and validity of Chinese version of early trauma inventory-short form%早年创伤问卷简表中文版的信度和效度

    王振; 杜江; 陈珏; 苑成梅; 王媛; 赵敏; 肖泽萍


    目的 评估早年创伤问卷简表(ETI-SF)中文版的信度和效度.方法 对265名被试进行ETI-SF中文版的评定,其中正常人42名、抑郁障碍94例,物质滥用者129例,130名在2~4周后重测.结果 ETI-SF四种童年创伤维度分量表的Cronbaeh's α系数在0.64~0.84之间,全量表Cronbach's α系数为0.83;重测相关系数在0.65~0.81之间(P<0.01);正常对照组各型童年创伤评分显著低于物质滥用和抑郁障碍组,3组中物质滥用组性创伤得分最高,抑郁障碍组情感虐待分最高,ETI-SF能有效区分.结论 ETI-SF中文版信度和效度较好,具有临床与科研应用价值.%Objective To assess the reliability and validity of the Chinese version of early trauma inventory-short form(ETI-SF).Methods The Chinese version of ETI-SF was administered to 265 participants including 42 health controls.94 depression disorder patients and 129 substance abusers.130 of them were retested after 2 to 4 weeks.Results The Cronbach's α coefficients of four childhood trauma domains'subscales ranged from 0.64 to 0.84(P<0.01).The Cronbach's α coefficients of the whole scale was 0.88.The test-retest coefficients ranged from 0.65 to 0.81(P<0.01).Health control group showed significant lower childhood trauma experience than depression disorder group and substance abuse group.Among three groups,substance abuse subjects showed highest sexual trauma while depression disorder subjects showed highest emotional abuse.ETI-SF can effectively differentiate different groups.Conclusion The Chinese version of ETI-SF shows acceptable reliability and validity.It's a promising assessment tool to evaluate childhood trauma in future clinical practice and research.

  20. Reliability and validity of the medical outcomes study, a 36-item short-form health survey, (MOS SF-36 after one-year hospital discharge of hip fracture patient in a public hospital

    Anan Udombhornprabha


    Full Text Available Introduction: There is scarce of data in terms of health-related quality of life for hip fracture patients in Thailand due to the following: (i lack of epidemiological aspects of hip fracture (eg. the relative incidence of osteoporosis, falls fractures and repeat fractures in particular subgroups, (ii lack of health status and quality of life aspects of both illness itself and the availability of different treatment options especially for elderly people. (iii a substantial variation in terms of outcomes of care for patients and service for hip fractures. Objective: Hip fracture is a major healthcare burden in Thailand. This study explores quality of life for hip fracture patients from perspective of (i Reliability of patient-reported outcomes (ii Some clinical and demographic characteristics related to patient-reported outcomes Method: Pre-hospital discharge 201 hip fracture patients were screened and follow-up over one year. Mail survey by a self-rated Medical Outcomes Study, a 36-item Short-Form Health Survey (Thai dispatched for follow-up, other clinical and demographic characteristics were collected through direct interviews from patients or caregivers during recruitment with simultaneous crosschecking from medical records. A descriptive cross-sectional analysis was performed.Result: Mails responder represented by 59.2% (N=119, with 36.1% (N=43 and 63.8% (N=76 for patient and caregiver rated outcomes. Mean(SD, [95% CI] score for physical, mental and global health of patient and care-giver rated outcomes of 36.2(10.6[32.9-39.4], 54.5(10.0[51.4-57.5],43.9(9.3[41.0-46.7], and 34.6(12.3[31.7-37.4], 52.5(12.3[49.6-55.3],42.7(11.1[40.1-45.2] were not statistically difference with p-value at 0.630,0.330 and 0.788 respectively. Respecting Cronbach’s alpha reliability coefficient by patients versus caregivers rated of the MOS SF-36 were 0.90 vs 0.91, 0.78 vs 0.84 and 0.90 vs 0.92. The presence of comorbidity significantly explains differences for

  1. 采煤机高可靠性机电液短程截割传动系统%High Reliability Electromechanical-hydraulic Short-range Cutting Transmission System of Shearer

    杨阳; 邹佳航; 秦大同; 袁瑷辉


    The cutting unit is the most important component of the shearer, but it is also the part that produces failure easily. Aim at solving the shearer’s low reliability and poor adaptability, a new kind of high reliability electromechanical-hydraulic short-range cutting transmission system is designed. The system can realize buffering and damping with the load’s mutation and the roller speed can be controlled with the variation of coal seam. The mathematical models of the cutting motor, the pump control motor system and the accumulator are established. The simulation model of MG300 shearer cutting transmission system is established based on AMESim software. The efficiency and the performance of speed regulation and coping with the load’s mutation are analyzed by the simulation. The results show that the system can not only regulate roller speed well but also process the buffering and damping function and keep high transmission efficiency in the typical working conditions. Consequently, the system can improve shearer’s reliability and adaptability. The simulation results illustrate the effectiveness and feasibility of the program which lays the foundation for the design and optimization of the cutting transmission system of shearer.%截割部是滚筒采煤机最重要的组成部分,也是最易产生失效的部分。针对现有滚筒采煤机截割部可靠性低和适应性差的问题,设计一种高可靠性机电液短程截割传动系统,该系统实现了负载突变下的缓冲减振和煤层变化下的滚筒调速。建立截割电动机、泵控马达系统和蓄能器的数学模型,基于AMESim软件建立MG300采煤机截割传动系统的仿真模型并进行系统调速性能、应对突变工况性能仿真分析和效率分析,结果表明系统既能实现滚筒转速的良好调节又具有一定的缓冲减振功能并且在典型工况下有着较高的传递效率。因此,所设计系统能提高采煤机的

  2. Microelectronics Reliability


    convey any rights or permission to manufacture, use, or sell any patented invention that may relate to them. This report was cleared for public release...testing for reliability prediction of devices exhibiting multiple failure mechanisms. Also presented was an integrated accelerating and measuring ...13  Table 2  T, V, F and matrix versus  measured  FIT

  3. Grid reliability

    Saiz, P; Rocha, R; Andreeva, J


    We are offering a system to track the efficiency of different components of the GRID. We can study the performance of both the WMS and the data transfers At the moment, we have set different parts of the system for ALICE, ATLAS, CMS and LHCb. None of the components that we have developed are VO specific, therefore it would be very easy to deploy them for any other VO. Our main goal is basically to improve the reliability of the GRID. The main idea is to discover as soon as possible the different problems that have happened, and inform the responsible. Since we study the jobs and transfers issued by real users, we see the same problems that users see. As a matter of fact, we see even more problems than the end user does, since we are also interested in following up the errors that GRID components can overcome by themselves (like for instance, in case of a job failure, resubmitting the job to a different site). This kind of information is very useful to site and VO administrators. They can find out the efficien...

  4. 简版心理健康连续体量表(成人版)的信效度%Reliability and validity of the Mental Health Continuum Short Form in adults

    尹可丽; 何嘉梅


    目的:检验简版心理健康连续体量表(MHC-SF)(成人版)在中国成人中使用的信度与效度.方法:对Keyes编制的MHC-SF(成人版)进行翻译,并由12名成人对MHC-SF(成人版)的项目进行评价.采取方便取样的方法,抽取北京、广东、云南、重庆、陕西、湖北等地的1981名成人,用MHC-SF(成人版)、幸福感脸形评尺、流调抑郁量表(CES-D)对MHC-SF(成人版)的结构效度、效标关联效度和内部一致性信度进行考察.结果:MHC-SF(成人版)包括情绪幸福感、社会幸福感和心理幸福感3个因素,共14个条目.MHC-SF(成人版)原量表的三因子结构与实际数据相契合,其拟合指数分别为x2 =975.62、df=74、RMSEA=0.08、 GFI=0.93、 AGFI=0.90、NFI=0.95、CFI=0.95. MHC-SF(成人版)总分及3个因子分与幸福感脸形评尺得分正相关(r =0.37~0.46,均P<0.01),而与CES-D得分负相关(r=-0.36~-0.48,均P<0.01).总量表的内部一致性Cronbach α系数为0.94,3个分量表的α系数为0.92、0.83、0.91.结论:简版心理健康连续体量表(成人版)的结构效度、效标关联效度及内部一致性信度达到了心理测量学的要求,可用于测量中国成人的积极心理健康状况.%Objective: To test the reliability and validity of the Mental Health Continuum Short Form (MHC-SF) in Chinese adults. Methods: The MHC-SF which developed by Keyes was translated into Chinese version, and 12 adults finished with the Chinese version of MHC-SF, and were asked to report their views on items of MHC-SF. The investigation sample consisted of 1981 adults from Beijing, Guangdong, Yunnan, Chongqing, Shanxi, and Hubei by convenience sampling. They were assessed with the Chinese version of MHC-SF for item analysis, confirmatory factor analysis, and internal consistency analysis, and they were assessed with the Subjective Well-being Face Scale and Center for Epidemiological Studies Depression Scale (CES-D) for criterion validity. Results: The

  5. Frontiers of reliability

    Basu, Asit P; Basu, Sujit K


    This volume presents recent results in reliability theory by leading experts in the world. It will prove valuable for researchers, and users of reliability theory. It consists of refereed invited papers on a broad spectrum of topics in reliability. The subjects covered include Bayesian reliability, Bayesian reliability modeling, confounding in a series system, DF tests, Edgeworth approximation to reliability, estimation under random censoring, fault tree reduction for reliability, inference about changes in hazard rates, information theory and reliability, mixture experiment, mixture of Weibul

  6. Reliability of electrical power systems for coal mines

    Razgil' deev, G.I.; Kovalev, A.P.; Serkyuk, L.I.


    This is a method for evaluating the reliability of comprehensive mining power systems. The systems reliability is influenced by the selectivity of maximum protection, ground-short protection, the subdivision of the circuitry, the character of the systems failures, etc.

  7. Lifetime Reliability Assessment of Concrete Slab Bridges

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed. Fi...

  8. Delta-Reliability

    Eugster, P.; Guerraoui, R.; Kouznetsov, P.


    This paper presents a new, non-binary measure of the reliability of broadcast algorithms, called Delta-Reliability. This measure quantifies the reliability of practical broadcast algorithms that, on the one hand, were devised with some form of reliability in mind, but, on the other hand, are not considered reliable according to the ``traditional'' notion of broadcast reliability [HT94]. Our specification of Delta-Reliability suggests a further step towards bridging the gap between theory and...

  9. Reliability computation from reliability block diagrams

    Chelson, P. O.; Eckstein, E. Y.


    Computer program computes system reliability for very general class of reliability block diagrams. Four factors are considered in calculating probability of system success: active block redundancy, standby block redundancy, partial redundancy, and presence of equivalent blocks in the diagram.

  10. VLSI Reliability in Europe

    Verweij, Jan F.


    Several issue's regarding VLSI reliability research in Europe are discussed. Organizations involved in stimulating the activities on reliability by exchanging information or supporting research programs are described. Within one such program, ESPRIT, a technical interest group on IC reliability was

  11. Short tunnels.

    Schreuder, D.A.


    Before dealing with the question of lighting short tunnels, it is necessary define what is meant by a tunnel and when it should be called 'short'. Confined to motorized road traffic the following is the most apt definition of a tunnel: every form of roofing-over a road section, irrespective of it le

  12. Reliability Generalization: "Lapsus Linguae"

    Smith, Julie M.


    This study examines the proposed Reliability Generalization (RG) method for studying reliability. RG employs the application of meta-analytic techniques similar to those used in validity generalization studies to examine reliability coefficients. This study explains why RG does not provide a proper research method for the study of reliability,…

  13. Reliability Analysis on English Writing Test of SHSEE in Shanghai

    黄玉麒; 黄芳


    As a subjective test, the validity of writing test is acceptable. What about the reliability? Writing test occupies a special position in the senior high school entrance examination (SHSEE for short). It is important to ensure its reliability. By the analysis of recent years’English writing items in SHSEE, the author offer suggestions on how to guarantee the reliability of writing tests.

  14. Short stature

    ... condition. Bone or skeletal disorders, such as: Rickets Achondroplasia Chronic diseases, such as: Asthma Celiac disease Congenital ... growth seems slow or your child seems small. TREATMENT Your child's short stature may affect her self- ...

  15. Short communication

    preferred customer

    ABSTRACT: Nutrients, metabolizable energy (ME), anti-nutritional factors, digestible organic ... for animals are in short supply and expensive, ... peels from hotels (Hawassa); sisal waste from ..... chain omega-3 fatty acids in livestock meat and.

  16. Reliability Of A Surgeon-Reported Morbidity And Mortality Database: A Comparison Of Short-Term Morbidity Between The Scoliosis Research Society And National Surgical Quality Improvement Program Databases

    Martin, Christopher T.; Pugely, Andrew J.; Gao, Yubo; Skovrlj, Branko; Lee, Nathan J.; Cho, Samuel K.; Mendoza-Lattes, Sergio


    Background There exists a lack of comparison between large national healthcare databases reporting surgical morbidity and mortality. Prior authors have expressed concern that the Scoliosis Research Society (SRS) membership may have underreported complications in spinal surgery. Thus, the purpose of the present study was to compare the incidence of morbidity between the SRS and National Surgical Quality Improvement Program (NSQIP) databases. Methods We reviewed patients enrolled between 2012 and 2013, with a total of 96,875 patients identified in the SRS dataset and 15,909 in the combined adult and pediatric NSQIP dataset. Patients were matched based on diagnostic category,and a univariate analysis was used to compare reported complication rates in the categories of perioperative infection, neurologic injury, and mortality. The SRS database only requires detailed demographic data reporting on patients that have had a complication event. We compared the demographics and comorbidities of this subgroup, and used this as a surrogate to assess the potential magnitude of confounders. Results Small differences existed between the SRS and NSQIP databases in terms of mortality (0.1% v. 0.2%), infection (1.2% v. 2%), and neurologic injury (0.8% v. 0.1%) (p<0.001 for each comparison). Infection rates were consistently lower across multiple diagnostic sub-categories in the SRS database, whereas neurologic injury rates were consistently lower in the NSQIP database. These differences reached statistical significance across several diagnostic subcategories, but the clinical magnitude of the differences was small. Amongst the patients with a complication, modest differences in comorbidities existed between the two cohorts. Conclusion Overall, the incidence of short-term morbidity and mortality was similar between the two databases. There were modest differences in comorbidities, which may explain the small differences observed in morbidity. Concerns regarding possible under

  17. Assuring reliability program effectiveness.

    Ball, L. W.


    An attempt is made to provide simple identification and description of techniques that have proved to be most useful either in developing a new product or in improving reliability of an established product. The first reliability task is obtaining and organizing parts failure rate data. Other tasks are parts screening, tabulation of general failure rates, preventive maintenance, prediction of new product reliability, and statistical demonstration of achieved reliability. Five principal tasks for improving reliability involve the physics of failure research, derating of internal stresses, control of external stresses, functional redundancy, and failure effects control. A final task is the training and motivation of reliability specialist engineers.

  18. The Accelerator Reliability Forum

    Lüdeke, Andreas; Giachino, R


    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  19. Enlightenment on Computer Network Reliability From Transportation Network Reliability

    Hu Wenjun; Zhou Xizhao


    Referring to transportation network reliability problem, five new computer network reliability definitions are proposed and discussed. They are computer network connectivity reliability, computer network time reliability, computer network capacity reliability, computer network behavior reliability and computer network potential reliability. Finally strategies are suggested to enhance network reliability.

  20. Human Reliability Program Overview

    Bodin, Michael


    This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

  1. Power electronics reliability analysis.

    Smith, Mark A.; Atcitty, Stanley


    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  2. Fatigue reliability for LNG carrier

    Xiao Taoyun; Zhang Qin; Jin Wulei; Xu Shuai


    The procedure of reliability-based fatigue analysis of liquefied natural gas (LNG) carrier of membrane type under wave loads is presented. The stress responses of the hotspots in regular waves with different wave heading angles and wave lengths are evaluated by global ship finite element method (FEM). Based on the probabilistic distribution function of hotspots' short-term stress-range using spectral-based analysis, Weibull distribution is adopted and discussed for fitting the long-term probabilistic distribution of stress-range. Based on linear cumulative damage theory, fatigue damage is characterized by an S-N relationship, and limit state function is established. Structural fatigue damage behavior of several typical hotspots of LNG middle ship section is clarified and reliability analysis is performed. It is believed that the presented results and conclusions can be of use in calibration for practical design and initial fatigue safety evaluation for membrane type LNG carrier.

  3. Reliable Design Versus Trust

    Berg, Melanie; LaBel, Kenneth A.


    This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?

  4. Viking Lander reliability program

    Pilny, M. J.


    The Viking Lander reliability program is reviewed with attention given to the development of the reliability program requirements, reliability program management, documents evaluation, failure modes evaluation, production variation control, failure reporting and correction, and the parts program. Lander hardware failures which have occurred during the mission are listed.

  5. Short Review

    Lynnerup, Niels; Rühli, Frank


    modality in ancient mummy research. The aim of this short review is to address the advantages and pitfalls of this particular technique for such unique samples. We recommend that when results of X-ray examination of mummies are presented, the specific recording data should be listed, and any given finds......, for example, of Paleopathology, should be cross-checked against other sources, for example, CT-scanning, direct inspection (also by endoscopy), and so forth....

  6. Reliability and safety engineering

    Verma, Ajit Kumar; Karanki, Durga Rao


    Reliability and safety are core issues that must be addressed throughout the life cycle of engineering systems. Reliability and Safety Engineering presents an overview of the basic concepts, together with simple and practical illustrations. The authors present reliability terminology in various engineering fields, viz.,electronics engineering, software engineering, mechanical engineering, structural engineering and power systems engineering. The book describes the latest applications in the area of probabilistic safety assessment, such as technical specification optimization, risk monitoring and risk informed in-service inspection. Reliability and safety studies must, inevitably, deal with uncertainty, so the book includes uncertainty propagation methods: Monte Carlo simulation, fuzzy arithmetic, Dempster-Shafer theory and probability bounds. Reliability and Safety Engineering also highlights advances in system reliability and safety assessment including dynamic system modeling and uncertainty management. Cas...

  7. Reliability Demands in FTTH Access Networks

    Pedersen, Jens Myrup; Knudsen, Thomas Phillip; Madsen, Ole Brun


    In this paper reliability and bandwidth demands of existing, new and expected classes of applications running over Fiber To The Home (FTTH) networks to private users and small enterprises are analysed and discussed. Certain applications such as home security and telemedicine are likely to require...... high levels of reliability in the sense that the demands for network availability are high; even short times without connectivity are unacceptable. To satisfy these demands, physical redundancy in the networks is needed. It seems to be the case that - at least in the short term - most reliability......-critical applications do not require much bandwidth. This implies that redundancy do not need to be by fiber, but can be ensured by e.g. coax, copper or wireless solutions. However, implementing these solutions need careful planning to ensure the physical redundancy. In the long term, it is more likely that physical...

  8. Reliability Demands in FTTH Access Networks

    Pedersen, Jens Myrup; Knudsen, Thomas Phillip; Madsen, Ole Brun


    In this paper reliability and bandwidth demands of existing, new and expected classes of applications running over Fiber To The Home (FTTH) networks to private users and small enterprises are analyzed and discussed. Certain applications such as home security and telemedicine are likely to require...... high levels of reliability in the sense that the demands for network availability are high; even short times without connectivity are unacceptable. To satisfy these demands, physical redundancy in the networks is needed. It seems to be the case that - at least in the short term - most reliability......-critical applications do not require much bandwidth. This implies that redundancy do not need to be by fiber, but can be ensured by e.g. coax, copper or wireless solutions. However, implementing these solutions need careful planning to ensure the physical redundancy. In the long term, it is more likely that physical...

  9. Measurement System Reliability Assessment

    Kłos Ryszard


    Full Text Available Decision-making in problem situations is based on up-to-date and reliable information. A great deal of information is subject to rapid changes, hence it may be outdated or manipulated and enforce erroneous decisions. It is crucial to have the possibility to assess the obtained information. In order to ensure its reliability it is best to obtain it with an own measurement process. In such a case, conducting assessment of measurement system reliability seems to be crucial. The article describes general approach to assessing reliability of measurement systems.

  10. Reliable knowledge discovery

    Dai, Honghua; Smirnov, Evgueni


    Reliable Knowledge Discovery focuses on theory, methods, and techniques for RKDD, a new sub-field of KDD. It studies the theory and methods to assure the reliability and trustworthiness of discovered knowledge and to maintain the stability and consistency of knowledge discovery processes. RKDD has a broad spectrum of applications, especially in critical domains like medicine, finance, and military. Reliable Knowledge Discovery also presents methods and techniques for designing robust knowledge-discovery processes. Approaches to assessing the reliability of the discovered knowledge are introduc

  11. Reliability of fluid systems

    Kopáček Jaroslav


    Full Text Available This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element, which is seen as a random variable and their data (values can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.

  12. Circuit design for reliability

    Cao, Yu; Wirth, Gilson


    This book presents physical understanding, modeling and simulation, on-chip characterization, layout solutions, and design techniques that are effective to enhance the reliability of various circuit units.  The authors provide readers with techniques for state of the art and future technologies, ranging from technology modeling, fault detection and analysis, circuit hardening, and reliability management. Provides comprehensive review on various reliability mechanisms at sub-45nm nodes; Describes practical modeling and characterization techniques for reliability; Includes thorough presentation of robust design techniques for major VLSI design units; Promotes physical understanding with first-principle simulations.

  13. Short esophagus.

    Kunio, Nicholas R; Dolan, James P; Hunter, John G


    In the presence of long-standing and severe gastroesophageal reflux disease, patients can develop various complications, including a shortened esophagus. Standard preoperative testing in these patients should include endoscopy, esophagography, and manometry, whereas the objective diagnosis of a short esophagus must be made intraoperatively following adequate mediastinal mobilization. If left untreated, it is a contributing factor to the high recurrence rate following fundoplications or repair of large hiatal hernias. A laparoscopic Collis gastroplasty combined with an antireflux procedure offers safe and effective therapy.

  14. LED system reliability

    Driel, W.D. van; Yuan, C.A.; Koh, S.; Zhang, G.Q.


    This paper presents our effort to predict the system reliability of Solid State Lighting (SSL) applications. A SSL system is composed of a LED engine with micro-electronic driver(s) that supplies power to the optic design. Knowledge of system level reliability is not only a challenging scientific ex

  15. Principles of Bridge Reliability

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  16. Improving machinery reliability

    Bloch, Heinz P


    This totally revised, updated and expanded edition provides proven techniques and procedures that extend machinery life, reduce maintenance costs, and achieve optimum machinery reliability. This essential text clearly describes the reliability improvement and failure avoidance steps practiced by best-of-class process plants in the U.S. and Europe.

  17. Chapter 9: Reliability

    Algora, Carlos; Espinet-Gonzalez, Pilar; Vazquez, Manuel; Bosco, Nick; Miller, David; Kurtz, Sarah; Rubio, Francisca; McConnell,Robert


    This chapter describes the accumulated knowledge on CPV reliability with its fundamentals and qualification. It explains the reliability of solar cells, modules (including optics) and plants. The chapter discusses the statistical distributions, namely exponential, normal and Weibull. The reliability of solar cells includes: namely the issues in accelerated aging tests in CPV solar cells, types of failure and failures in real time operation. The chapter explores the accelerated life tests, namely qualitative life tests (mainly HALT) and quantitative accelerated life tests (QALT). It examines other well proven and experienced PV cells and/or semiconductor devices, which share similar semiconductor materials, manufacturing techniques or operating conditions, namely, III-V space solar cells and light emitting diodes (LEDs). It addresses each of the identified reliability issues and presents the current state of the art knowledge for their testing and evaluation. Finally, the chapter summarizes the CPV qualification and reliability standards.

  18. Demand Response For Power System Reliability: FAQ

    Kirby, Brendan J [ORNL


    Demand response is the most underutilized power system reliability resource in North America. Technological advances now make it possible to tap this resource to both reduce costs and improve. Misconceptions concerning response capabilities tend to force loads to provide responses that they are less able to provide and often prohibit them from providing the most valuable reliability services. Fortunately this is beginning to change with some ISOs making more extensive use of load response. This report is structured as a series of short questions and answers that address load response capabilities and power system reliability needs. Its objective is to further the use of responsive load as a bulk power system reliability resource in providing the fastest and most valuable ancillary services.

  19. Reliability and Validity of MOS-36-item Short Form of Health Survey Measuring the Quality of Life among Disabled People%SF-36量表测量伤残人员生存质量的信度与效度

    吴学华; 李小麟


    目的 评价SF-36量表在测量地震伤残人员生存质量中的信度和效度.方法 利用自填法及访谈相结合的方式调查201例绵竹市某镇地震伤残人员,用重测信度和Cronbach's a系数分析SF-36信度;因子分析方法分析效度.结果 SF-36各领域的重测信度分别为:生理功能(PF)0.78、生理问题对功能的限制(RP)0.85、躯体疼痛(BP)0.92、健康总体评价(GH)0.82、活力(VT)0.77、社会功能(SF)0.71、心理问题对功能的限制(RE)0.79、精神健康(MH)0.66;各领域的Cronbach's a系数分别为:PF 0.89、RP 0.75、BP 0.84、GH 0.86、VT 0.78、SF 0.72、RE0.86、MH 0.50.因子分析共提取了6个主成分,基本反映了量表的8个维度,与量表的结构构思基本相符.结果 自填法及面对面访谈相结合的方式,将SF-36量表用于该地地震伤残人员生存质量测定具有较好的信度和效度.%Objective To evaluate the validity and reliability of the MOS-36-item Short Form of Health Survey (SF-36) measuring the quality of life (QOL) of disabled people injured in the earthquake. Methods A total of 201disabled people injured in the earthquake in a town of Mianzhu city were investigated via questionnaire combined with a face-to-face interview. The reliability of the SF-36 was assessed by test-reteat reliability and Cronbach's α coefficient.The validity was assessed through factor analysis. Results The test-retest reliability of the SF-36 included: physical functioning (PF) 0. 78, role limitation due to physical problems (RP) 0. 85, body pain (BP) 0. 92, general health (GH) 0. 82, vitality (VT) 0. 77, social functioning (SF) 0. 71, role limitation due to emotional problems (RE) 0. 79,and mental health (MH) 0. 66. The Cronbachs α coefficients were as the follows: PF 0. 89, RP 0. 75, BP 0. 84, GH 0. 86, VT 0. 78, SF 0. 72, RE 0. 86, and MH 0. 50. Six principal components were extracted by factor analysis and the constructs of the obtained instrument were consistent with

  20. Photovoltaic system reliability

    Maish, A.B.; Atcitty, C. [Sandia National Labs., NM (United States); Greenberg, D. [Ascension Technology, Inc., Lincoln Center, MA (United States)] [and others


    This paper discusses the reliability of several photovoltaic projects including SMUD`s PV Pioneer project, various projects monitored by Ascension Technology, and the Colorado Parks project. System times-to-failure range from 1 to 16 years, and maintenance costs range from 1 to 16 cents per kilowatt-hour. Factors contributing to the reliability of these systems are discussed, and practices are recommended that can be applied to future projects. This paper also discusses the methodology used to collect and analyze PV system reliability data.

  1. Structural Reliability Methods

    Ditlevsen, Ove Dalager; Madsen, H. O.

    of structural reliability, including the theoretical basis for these methods. Partial safety factor codes under current practice are briefly introduced and discussed. A probabilistic code format for obtaining a formal reliability evaluation system that catches the most essential features of the nature......The structural reliability methods quantitatively treat the uncertainty of predicting the behaviour and properties of a structure given the uncertain properties of its geometry, materials, and the actions it is supposed to withstand. This book addresses the probabilistic methods for evaluation...

  2. Reliable Electronic Equipment

    N. A. Nayak


    Full Text Available The reliability aspect of electronic equipment's is discussed. To obtain optimum results, close cooperation between the components engineer, the design engineer and the production engineer is suggested.

  3. Reliability prediction techniques

    Whittaker, B.; Worthington, B.; Lord, J.F.; Pinkard, D.


    The paper demonstrates the feasibility of applying reliability assessment techniques to mining equipment. A number of techniques are identified and described and examples of their use in assessing mining equipment are given. These techniques include: reliability prediction; failure analysis; design audit; maintainability; availability and the life cycle costing. Specific conclusions regarding the usefulness of each technique are outlined. The choice of techniques depends upon both the type of equipment being assessed and its stage of development, with numerical prediction best suited for electronic equipment and fault analysis and design audit suited to mechanical equipment. Reliability assessments involve much detailed and time consuming work but it has been demonstrated that the resulting reliability improvements lead to savings in service costs which more than offset the cost of the evaluation.

  4. The rating reliability calculator

    Solomon David J


    Full Text Available Abstract Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program.

  5. Reliability of power connections

    BRAUNOVIC Milenko


    Despite the use of various preventive maintenance measures, there are still a number of problem areas that can adversely affect system reliability. Also, economical constraints have pushed the designs of power connections closer to the limits allowed by the existing standards. The major parameters influencing the reliability and life of Al-Al and Al-Cu connections are identified. The effectiveness of various palliative measures is determined and the misconceptions about their effectiveness are dealt in detail.

  6. Multidisciplinary System Reliability Analysis

    Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)


    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  7. Short apraxia screening test.

    Leiguarda, Ramon; Clarens, Florencia; Amengual, Alejandra; Drucaroff, Lucas; Hallett, Mark


    Limb apraxia comprises many different and common disorders, which are largely unrecognized essentially because there is no easy-to-use screening test sensitive enough to identify all types of limb praxis deficits. We evaluated 70 right-handed patients with limb apraxia due to a single focal lesion of the left hemisphere and 40 normal controls, using a new apraxia screening test. The test covered 12 items including: intransitive gestures, transitive gestures elicited under verbal, visual, and tactile modalities, imitation of meaningful and meaningless postures and movements, and a multiple object test. Interrater reliability was maximum for a cutoff of >2 positive items identifying apraxia on the short battery (Cohen's kappa .918, p 3 items (Cohen's kappa .768, p 2 was higher, indicating greater apraxia diagnosis agreement between raters at this cutoff value. The screening test proved to have high specificity and sensitivity to diagnose every type of upper limb praxis deficit, thus showing advantages over previously published tests.

  8. Sensitivity Analysis of Component Reliability



    In a system, Every component has its unique position within system and its unique failure characteristics. When a component's reliability is changed, its effect on system reliability is not equal. Component reliability sensitivity is a measure of effect on system reliability while a component's reliability is changed. In this paper, the definition and relative matrix of component reliability sensitivity is proposed, and some of their characteristics are analyzed. All these will help us to analyse or improve the system reliability.

  9. 中文版多维度疲乏症状量表-简表应用于癌症患者信效度的研究%The reliability and validity of the Chinese version of multidimensional fatigue symptom inventory-short form

    薛秀娟; 许翠萍; 薛琳; 刘庆芝; 张洁; 李燕; 徐泽俊


    Objective To assess the reliability and validity of the Chinese version of Multidimensional fatigue symptom inventory-short form(MFSI-SF).Methods The reliability and validity of the Chinese version MFSI-SF were assessed in a sample of 203 cancer patients.Statistical software was used to perform the analysis.Results The results showed moderate correlation between items and the total scale,the content validity index was 0.82,and exploratory factor analysis indicated five dimensions of the scale,the cumulative variance contribution was 56.65%.Confirmatory factor analysis showed moderate model fitting:x2/df=l.73,GFI=0.83,AGFI=0.79,NNFI=0.94,RMSEA=0.06,criterion validity was 0.585,and the Cronbach α of the total scale was 0.896.Conclusions The results demonstrated good convergent validity,it is suitable to evaluate fatigue status in Chinese cancer patients.%目的 验证并评价中文版多维度疲乏症状量表-简表(MFSI-SF)应用于中国癌症患者的信效度.方法 采用中文版MFSI-SF对203例癌症患者进行调查,运用统计软件对测定结果进行信效度分析.结果 中文版MFSI-SF所有条目与量表总分的相关系数为0.25~0.76,内容效度为0.82;探索性因子分析提取的5个公因子累计方差贡献率为56.65%;验证性因子分析结果为x2/df=l.73,GFI=0.83,AGFI=0.79,NNFI=0.94,RMSEA=0.06;效标效度为0.585;信度为0.896.结论 中文版MFSI-SF具有较好的信效度,可用于评价我国癌症患者的疲乏状态.


    Тамаргазін, О. А.; Національний авіаційний університет; Власенко, П. О.; Національний авіаційний університет


    Airline's operational structure for Reliability program implementation — engineering division, reliability  division, reliability control division, aircraft maintenance division, quality assurance division — was considered. Airline's Reliability program structure is shown. Using of Reliability program for reducing costs on aircraft maintenance is proposed. Рассмотрена организационная структура авиакомпании по выполнению Программы надежности - инженерный отдел, отделы по надежности авиацио...

  11. Ultra reliability at NASA

    Shapiro, Andrew A.


    Ultra reliable systems are critical to NASA particularly as consideration is being given to extended lunar missions and manned missions to Mars. NASA has formulated a program designed to improve the reliability of NASA systems. The long term goal for the NASA ultra reliability is to ultimately improve NASA systems by an order of magnitude. The approach outlined in this presentation involves the steps used in developing a strategic plan to achieve the long term objective of ultra reliability. Consideration is given to: complex systems, hardware (including aircraft, aerospace craft and launch vehicles), software, human interactions, long life missions, infrastructure development, and cross cutting technologies. Several NASA-wide workshops have been held, identifying issues for reliability improvement and providing mitigation strategies for these issues. In addition to representation from all of the NASA centers, experts from government (NASA and non-NASA), universities and industry participated. Highlights of a strategic plan, which is being developed using the results from these workshops, will be presented.

  12. Photovoltaic module reliability workshop

    Mrig, L. (ed.)


    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  13. 冲突策略量表(中文简版)在流动育龄妇女中应用的信效度%The Reliability and Validity of the Chinese Version of Short Form of the Co nflict Tactics Scale in Migrant Women of Childbearing age

    潘腾; 凌莉; 宋晓琴; 徐勇; 曾珈智


    Objective To assess the reliability and validity of the Chinese version of Short Form of the Conflict Tactics Scale in mi -grant women of childbearing age .Methods A convenient sample of 1051 migrant women of childbearing age in Baiyun District of Guan-gzhou completed the scale .Results The correlation coefficients between each items and the total score were between 0.18 to 0.64(P<0.01).The total Cronbach coefficient of the scale was 0.91.The total Cronbach coefficient of the subscales of Negotiation psychological aggrewon,assault,sexual coercion,injury were 0.77,0.720, .88,0.93,0.84;The total Guttman coefficient of the scale was 0.74.The to-tal Guttman coefficient of the subscales of Negotiation ,psychological aggrewon,assault,sexual coercion,injury were 0.64, 0.46,0.83, 0.88,0.62.Exploratory factor analyses showed that the scale was composed of 5 factors,cumulatively explained 73.34% of variance. Conclusion The reliability and validity of the Chinese version of revised Conflict Tactics Scale Short Form are strongly supported ,and can be adopted by researches for the measurement of intimate partner violence in domestic migrant women of childbearing age .%目的:评价冲突策略量表(中文简版)在流动育龄妇女中应用的信度和效度。方法采用便利抽样的方法在广州市白云区抽取1003例流动育龄妇女接受中文简版冲突策略量表的调查。结果中文简版冲突策略量表条目-总分相关系数在0.18~0.64之间(P<0.01),内部一致性Cronbach'sα系数为0.91,Guttman系数为0.74。其中,协商、心理攻击、躯体暴力、强迫性性行为、伤害各分量表的Cronbach's α系数依次为:0.77、0.72、0.88、0.93、0.84;Guttman系数依次为:0.64、0.46、0.83、0.89、0.62。经探索性因子分析提取5个公因子,可以累计解释73.34%的方差。结论中文简版冲突策略量表具有良好的信度和效度,可以稳定测量

  14. Reliability Centered Maintenance - Methodologies

    Kammerer, Catherine C.


    Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

  15. Gearbox Reliability Collaborative Update (Presentation)

    Sheng, S.; Keller, J.; Glinsky, C.


    This presentation was given at the Sandia Reliability Workshop in August 2013 and provides information on current statistics, a status update, next steps, and other reliability research and development activities related to the Gearbox Reliability Collaborative.

  16. System Reliability Analysis: Foundations.


    performance formulas for systems subject to pre- ventive maintenance are given. V * ~, , 9 D -2 SYSTEM RELIABILITY ANALYSIS: FOUNDATIONS Richard E...reliability in this case is V P{s can communicate with the terminal t = h(p) Sp2(((((p p)p) p)p)gp) + p(l -p)(((pL p)p)(p 2 JLp)) + p(l -p)((p(p p...For undirected networks, the basic reference is A. Satyanarayana and Kevin Wood (1982). For directed networks, the basic reference is Avinash

  17. The adaptation of Flow Short Scale to Turkish: A validity and reliability studyFlow Yaşantısı Ölçeği Kısa Formunun Türkçeye uyarlama, geçerlik ve güvenirlik çalışması

    Bahar İşigüzel


    Full Text Available The aim of this study is to evaluate the validity and reliability of the Flow Short Scale that was developed by Rheinberg, Vollmeyer ve Engeser (2003 in Germany, for Turkey’s conditions. 222 university prep class students (124 female; 98 male participated in the study. The validity of scale was investigated by construct and criterion related validity methods and the reliability analysis of the scale, measured by assessing the internal consistency parameter. The factor structure of the scale was investigated by exploratory factor analysis (EFA. The results of the analysis showed that the factor structures of the scale, which has two complementary sub- scales (flow- anxiety, were similar with the original scale.  It is found that the adapted scales internal reliability co- efficient was .78. The foreign language achievement final points of the semester were used for the criterion validity. There was r=.21 correlation between flow experience and the language achievement final points and r=.34 correlation between anxiety and the language achievement final points (p<.01. The findings revealed that the Flow Short Scale was a reliable and valid instrument for measuring university students’ Flow Experiences by the foreign language lessons in prep- classes. ÖzetBu çalışmanın amacı, Rheinberg, Vollmeyer ve Engeser (2003 tarafından geliştirilen Flow Yaşantısı Ölçeği Kısa Formu’nun (Flow Kurz Skala Türkçeye uyarlama, geçerlik ve güvenirlik çalışmasını yapmaktır. Araştırmaya 124’ü kadın, 98’i erkek toplam 222 yabancı dil hazırlık sınıfı üniversite öğrencisi katılmıştır. Ölçeğin geçerliğine yapı geçerliği ve ölçüt bağlantılı geçerlik yaklaşımlarıyla bakılmıştır. Aracın güvenirliği ise iç tutarlık katsayısı hesaplanarak incelenmiştir. Ölçeğin basit ve kararlı bir yapıya sahip olup olmadığını anlamak için Açıklayıcı Faktör Analizi uygulanmıştır.

  18. Reliability and Validity of the Peritoneal Dialysis Empowerment Scale -Short Form in the Assessment of the ;Empowerment Ability of Peritoneal Dialysis Patients%腹膜透析授权简化量表评估腹膜透析患者授权能力的信效度

    孙春艳; 张清


    Objective To explore the reliability and validity of the peritoneal dialysis empowerment scale-short form ( PDES-SF) among peritoneal dialysis patients.Methods A total of 136 patients who conducted peritoneal dialysis by manual manipulation in peritoneal dialysis center of Nephrology Department of Tianjin First Central Hospital were enrolled from March to May in 2015.Chinese diabetes empowerment scale-short form ( C-DES-SF) was adapted into PDES-SF by expert enquiry; the patients with peritoneal dialysis were surveyed by PDES-SF, self-efficacy for managing chronic disease 6 item scale ( SES6 ) , self-management scale for peritoneal dialysis patients ( SMSPD ) , self -esteem scale ( SES ) and sense of coherence -13 ( SOC-13 ) . And the biochemistry indicators of patients with peritoneal dialysis were collected in the corresponding period.Results The PDES-SF score of the patients with peritoneal dialysis was ( 4.1 ±0.7 ) and the C-DES-SF score of diabetes patients including Hu Beibei was (3.9 ±0.7); the difference was significant (t=3.48, P=0.001) .The consistency level ( IR) between ultimate valuators about PDES-SF was 0.875 by validity test; the range of content validity index ( I-CVI) about level of entries was 0.80-1.00; the scale-level content validity index/average ( S-CVI/Ave) was 0.95; scale-level content validity index/universal agreement ( S-CVI/UA) was 0.88.The PDES-SF score was positively correlated with SES6 ( r=0.549, P<0.01), SMSPD (r=0.414, P<0.01), SES (r=0.404, P<0.01) and SOC-13 (r=0.522, P<0.01) score, albumin level (r=0.216, P<0.05) and intact parathyroid hormone (iPTH) (r=0.224, P<0.05) .PDES-SF Cronbach′sαcoefficient was 0.851 and test-retest reliability was 0.963 by reliability test.Conclusion PDES-SF has good reliability and validity and is suitable for measuring the empowerment ability of peritoneal dialysis patients.%目的:探讨腹膜透析授权简化量表( PDES-SF)在腹膜透析患者中应用的信效度。方法选取2015

  19. Power Industry Reliability Coordination in Asia in a Market Environment

    Nikolai I. Voropai


    Full Text Available This paper addresses the problems of power supply reliability in a market environment. The specific features of economic interrelations between the power supply organization and consumers in terms of reliability assurance are examined and the principles of providing power supply reliability are formulated. The economic mechanisms of coordinating the interests of power supply organization and consumers to provide power supply reliability are discussed. Reliability of restructuring China's power industry is introduced. Some reliability data is provided. The data shows that the reliability level has increased significantly in the past two decades. More and more measures are being applied to guarantee reliability of the restructured power systems. The reliability issues and challenges that are facing the Chinese power industry are considered The paper, then examines the evolution of power grids in India, the establishment of a regulatory framework, and operational philosophy in reliability aspects of long-, mid- as well as short-term (operational / outage planning. Grid security, restoration, and mock trial for black start, etc. from the reliability angle are considered. Related issues for islanding operation to improve service reliability for Thailand's Electric Power System are then analyzed.

  20. Expert system aids reliability

    Johnson, A.T. [Tennessee Gas Pipeline, Houston, TX (United States)


    Quality and Reliability are key requirements in the energy transmission industry. Tennessee Gas Co. a division of El Paso Energy, has applied Gensym`s G2, object-oriented Expert System programming language as a standard tool for maintaining and improving quality and reliability in pipeline operation. Tennessee created a small team of gas controllers and engineers to develop a Proactive Controller`s Assistant (ProCA) that provides recommendations for operating the pipeline more efficiently, reliably and safely. The controller`s pipeline operating knowledge is recreated in G2 in the form of Rules and Procedures in ProCA. Two G2 programmers supporting the Gas Control Room add information to the ProCA knowledge base daily. The result is a dynamic, constantly improving system that not only supports the pipeline controllers in their operations, but also the measurement and communications departments` requests for special studies. The Proactive Controller`s Assistant development focus is in the following areas: Alarm Management; Pipeline Efficiency; Reliability; Fuel Efficiency; and Controller Development.

  1. Reliability based structural design

    Vrouwenvelder, A.C.W.M.


    According to ISO 2394, structures shall be designed, constructed and maintained in such a way that they are suited for their use during the design working life in an economic way. To fulfil this requirement one needs insight into the risk and reliability under expected and non-expected actions. A ke

  2. Reliability based structural design

    Vrouwenvelder, A.C.W.M.


    According to ISO 2394, structures shall be designed, constructed and maintained in such a way that they are suited for their use during the design working life in an economic way. To fulfil this requirement one needs insight into the risk and reliability under expected and non-expected actions. A ke

  3. The value of reliability

    Fosgerau, Mogens; Karlström, Anders


    We derive the value of reliability in the scheduling of an activity of random duration, such as travel under congested conditions. Using a simple formulation of scheduling utility, we show that the maximal expected utility is linear in the mean and standard deviation of trip duration, regardless...

  4. Parametric Mass Reliability Study

    Holt, James P.


    The International Space Station (ISS) systems are designed based upon having redundant systems with replaceable orbital replacement units (ORUs). These ORUs are designed to be swapped out fairly quickly, but some are very large, and some are made up of many components. When an ORU fails, it is replaced on orbit with a spare; the failed unit is sometimes returned to Earth to be serviced and re-launched. Such a system is not feasible for a 500+ day long-duration mission beyond low Earth orbit. The components that make up these ORUs have mixed reliabilities. Components that make up the most mass-such as computer housings, pump casings, and the silicon board of PCBs-typically are the most reliable. Meanwhile components that tend to fail the earliest-such as seals or gaskets-typically have a small mass. To better understand the problem, my project is to create a parametric model that relates both the mass of ORUs to reliability, as well as the mass of ORU subcomponents to reliability.

  5. Avionics Design for Reliability


    Consultant P.O. Box 181, Hazelwood. Missouri 63042, U.S.A. soup ""•.• • CONTENTS Page LIST OF SPEAKERS iii INTRODUCTION AND OVERVIEW-RELIABILITY UNDER... primordial , d’autant plus quo dans co cam ia procg- dure do st~lection en fiabilitg eat assez peu efficaco. La ripartition des pannes suit

  6. Wind Energy - How Reliable.


    The reliability of a wind energy system depends on the size of the propeller and the size of the back-up energy storage. Design of the optimum system...speed incidents which generate a significant part of the wind energy . A nomogram is presented, based on some continuous wind speed measurements

  7. The reliability horizon

    Visser, M


    The ``reliability horizon'' for semi-classical quantum gravity quantifies the extent to which we should trust semi-classical quantum gravity, and gives a handle on just where the ``Planck regime'' resides. The key obstruction to pushing semi-classical quantum gravity into the Planck regime is often the existence of large metric fluctuations, rather than a large back-reaction.

  8. Reliability of semiology description.

    Heo, Jae-Hyeok; Kim, Dong Wook; Lee, Seo-Young; Cho, Jinwhan; Lee, Sang-Kun; Nam, Hyunwoo


    Seizure semiology is important for classifying patients' epilepsy. Physicians usually get most of the seizure information from observers though there have been few reports on the reliability of the observers' description. This study aims at determining the reliability of observers' description of the semiology. We included 92 patients who had their habitual seizures recorded during video-EEG monitoring. We compared the semiology described by the observers with that recorded on the videotape, and reviewed which characteristics of the observers affected the reliability of their reported data. The classification of seizures and the individual components of the semiology based only on the observer-description was somewhat discordant compared with the findings from the videotape (correct classification, 85%). The descriptions of some ictal behaviors such as oroalimentary automatism, tonic/dystonic limb posturing, and head versions were relatively accurate, but those of motionless staring and hand automatism were less accurate. The specified directions by the observers were relatively correct. The accuracy of the description was related to the educational level of the observers. Much of the information described by well-educated observers is reliable. However, every physician should keep in mind the limitations of this information and use this information cautiously.

  9. High reliability organizations

    Gallis, R.; Zwetsloot, G.I.J.M.


    High Reliability Organizations (HRO’s) are organizations that constantly face serious and complex (safety) risks yet succeed in realising an excellent safety performance. In such situations acceptable levels of safety cannot be achieved by traditional safety management only. HRO’s manage safety

  10. Reliability in the utility computing era: Towards reliable Fog computing

    Madsen, Henrik; Burtschy, Bernard; Albeanu, G.


    This paper considers current paradigms in computing and outlines the most important aspects concerning their reliability. The Fog computing paradigm as a non-trivial extension of the Cloud is considered and the reliability of the networks of smart devices are discussed. Combining the reliability...... requirements of grid and cloud paradigms with the reliability requirements of networks of sensor and actuators it follows that designing a reliable Fog computing platform is feasible....

  11. Human Reliability Program Workshop

    Landers, John; Rogers, Erin; Gerke, Gretchen


    A Human Reliability Program (HRP) is designed to protect national security as well as worker and public safety by continuously evaluating the reliability of those who have access to sensitive materials, facilities, and programs. Some elements of a site HRP include systematic (1) supervisory reviews, (2) medical and psychological assessments, (3) management evaluations, (4) personnel security reviews, and (4) training of HRP staff and critical positions. Over the years of implementing an HRP, the Department of Energy (DOE) has faced various challenges and overcome obstacles. During this 4-day activity, participants will examine programs that mitigate threats to nuclear security and the insider threat to include HRP, Nuclear Security Culture (NSC) Enhancement, and Employee Assistance Programs. The focus will be to develop an understanding of the need for a systematic HRP and to discuss challenges and best practices associated with mitigating the insider threat.

  12. Accelerator reliability workshop

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D


    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

  13. Reliability and construction control

    Sherif S. AbdelSalam


    Full Text Available The goal of this study was to determine the most reliable and efficient combination of design and construction methods required for vibro piles. For a wide range of static and dynamic formulas, the reliability-based resistance factors were calculated using EGYPT database, which houses load test results for 318 piles. The analysis was extended to introduce a construction control factor that determines the variation between the pile nominal capacities calculated using static versus dynamic formulae. From the major outcomes, the lowest coefficient of variation is associated with Davisson’s criterion, and the resistance factors calculated for the AASHTO method are relatively high compared with other methods. Additionally, the CPT-Nottingham and Schmertmann method provided the most economic design. Recommendations related to a pile construction control factor were also presented, and it was found that utilizing the factor can significantly reduce variations between calculated and actual capacities.

  14. Improving Power Converter Reliability

    Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon


    The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental...... is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation...

  15. Power electronics reliability.

    Kaplar, Robert James; Brock, Reinhard C.; Marinella, Matthew; King, Michael Patrick; Stanley, James K.; Smith, Mark A.; Atcitty, Stanley


    The project's goals are: (1) use experiments and modeling to investigate and characterize stress-related failure modes of post-silicon power electronic (PE) devices such as silicon carbide (SiC) and gallium nitride (GaN) switches; and (2) seek opportunities for condition monitoring (CM) and prognostics and health management (PHM) to further enhance the reliability of power electronics devices and equipment. CM - detect anomalies and diagnose problems that require maintenance. PHM - track damage growth, predict time to failure, and manage subsequent maintenance and operations in such a way to optimize overall system utility against cost. The benefits of CM/PHM are: (1) operate power conversion systems in ways that will preclude predicted failures; (2) reduce unscheduled downtime and thereby reduce costs; and (3) pioneering reliability in SiC and GaN.

  16. ATLAS reliability analysis

    Bartsch, R.R.


    Key elements of the 36 MJ ATLAS capacitor bank have been evaluated for individual probabilities of failure. These have been combined to estimate system reliability which is to be greater than 95% on each experimental shot. This analysis utilizes Weibull or Weibull-like distributions with increasing probability of failure with the number of shots. For transmission line insulation, a minimum thickness is obtained and for the railgaps, a method for obtaining a maintenance interval from forthcoming life tests is suggested.

  17. Reliability of Circumplex Axes

    Micha Strack


    Full Text Available We present a confirmatory factor analysis (CFA procedure for computing the reliability of circumplex axes. The tau-equivalent CFA variance decomposition model estimates five variance components: general factor, axes, scale-specificity, block-specificity, and item-specificity. Only the axes variance component is used for reliability estimation. We apply the model to six circumplex types and 13 instruments assessing interpersonal and motivational constructs—Interpersonal Adjective List (IAL, Interpersonal Adjective Scales (revised; IAS-R, Inventory of Interpersonal Problems (IIP, Impact Messages Inventory (IMI, Circumplex Scales of Interpersonal Values (CSIV, Support Action Scale Circumplex (SAS-C, Interaction Problems With Animals (IPI-A, Team Role Circle (TRC, Competing Values Leadership Instrument (CV-LI, Love Styles, Organizational Culture Assessment Instrument (OCAI, Customer Orientation Circle (COC, and System for Multi-Level Observation of Groups (behavioral adjectives; SYMLOG—in 17 German-speaking samples (29 subsamples, grouped by self-report, other report, and metaperception assessments. The general factor accounted for a proportion ranging from 1% to 48% of the item variance, the axes component for 2% to 30%; and scale specificity for 1% to 28%, respectively. Reliability estimates varied considerably from .13 to .92. An application of the Nunnally and Bernstein formula proposed by Markey, Markey, and Tinsley overestimated axes reliabilities in cases of large-scale specificities but otherwise works effectively. Contemporary circumplex evaluations such as Tracey’s RANDALL are sensitive to the ratio of the axes and scale-specificity components. In contrast, the proposed model isolates both components.

  18. Creep-rupture reliability analysis

    Peralta-Duran, A.; Wirsching, P. H.


    A probabilistic approach to the correlation and extrapolation of creep-rupture data is presented. Time temperature parameters (TTP) are used to correlate the data, and an analytical expression for the master curve is developed. The expression provides a simple model for the statistical distribution of strength and fits neatly into a probabilistic design format. The analysis focuses on the Larson-Miller and on the Manson-Haferd parameters, but it can be applied to any of the TTP's. A method is developed for evaluating material dependent constants for TTP's. It is shown that optimized constants can provide a significant improvement in the correlation of the data, thereby reducing modelling error. Attempts were made to quantify the performance of the proposed method in predicting long term behavior. Uncertainty in predicting long term behavior from short term tests was derived for several sets of data. Examples are presented which illustrate the theory and demonstrate the application of state of the art reliability methods to the design of components under creep.

  19. CR reliability testing

    Honeyman-Buck, Janice C.; Rill, Lynn; Frost, Meryll M.; Staab, Edward V.


    The purpose of this work was to develop a method for systematically testing the reliability of a CR system under realistic daily loads in a non-clinical environment prior to its clinical adoption. Once digital imaging replaces film, it will be very difficult to revert back should the digital system become unreliable. Prior to the beginning of the test, a formal evaluation was performed to set the benchmarks for performance and functionality. A formal protocol was established that included all the 62 imaging plates in the inventory for each 24-hour period in the study. Imaging plates were exposed using different combinations of collimation, orientation, and SID. Anthropomorphic phantoms were used to acquire images of different sizes. Each combination was chosen randomly to simulate the differences that could occur in clinical practice. The tests were performed over a wide range of times with batches of plates processed to simulate the temporal constraints required by the nature of portable radiographs taken in the Intensive Care Unit (ICU). Current patient demographics were used for the test studies so automatic routing algorithms could be tested. During the test, only three minor reliability problems occurred, two of which were not directly related to the CR unit. One plate was discovered to cause a segmentation error that essentially reduced the image to only black and white with no gray levels. This plate was removed from the inventory to be replaced. Another problem was a PACS routing problem that occurred when the DICOM server with which the CR was communicating had a problem with disk space. The final problem was a network printing failure to the laser cameras. Although the units passed the reliability test, problems with interfacing to workstations were discovered. The two issues that were identified were the interpretation of what constitutes a study for CR and the construction of the look-up table for a proper gray scale display.

  20. Ultimately Reliable Pyrotechnic Systems

    Scott, John H.; Hinkel, Todd


    This paper presents the methods by which NASA has designed, built, tested, and certified pyrotechnic devices for high reliability operation in extreme environments and illustrates the potential applications in the oil and gas industry. NASA's extremely successful application of pyrotechnics is built upon documented procedures and test methods that have been maintained and developed since the Apollo Program. Standards are managed and rigorously enforced for performance margins, redundancy, lot sampling, and personnel safety. The pyrotechnics utilized in spacecraft include such devices as small initiators and detonators with the power of a shotgun shell, detonating cord systems for explosive energy transfer across many feet, precision linear shaped charges for breaking structural membranes, and booster charges to actuate valves and pistons. NASA's pyrotechnics program is one of the more successful in the history of Human Spaceflight. No pyrotechnic device developed in accordance with NASA's Human Spaceflight standards has ever failed in flight use. NASA's pyrotechnic initiators work reliably in temperatures as low as -420 F. Each of the 135 Space Shuttle flights fired 102 of these initiators, some setting off multiple pyrotechnic devices, with never a failure. The recent landing on Mars of the Opportunity rover fired 174 of NASA's pyrotechnic initiators to complete the famous '7 minutes of terror.' Even after traveling through extreme radiation and thermal environments on the way to Mars, every one of them worked. These initiators have fired on the surface of Titan. NASA's design controls, procedures, and processes produce the most reliable pyrotechnics in the world. Application of pyrotechnics designed and procured in this manner could enable the energy industry's emergency equipment, such as shutoff valves and deep-sea blowout preventers, to be left in place for years in extreme environments and still be relied upon to function when needed, thus greatly enhancing

  1. Ferrite logic reliability study

    Baer, J. A.; Clark, C. B.


    Development and use of digital circuits called all-magnetic logic are reported. In these circuits the magnetic elements and their windings comprise the active circuit devices in the logic portion of a system. The ferrite logic device belongs to the all-magnetic class of logic circuits. The FLO device is novel in that it makes use of a dual or bimaterial ferrite composition in one physical ceramic body. This bimaterial feature, coupled with its potential for relatively high speed operation, makes it attractive for high reliability applications. (Maximum speed of operation approximately 50 kHz.)

  2. Blade reliability collaborative :

    Ashwill, Thomas D.; Ogilvie, Alistair B.; Paquette, Joshua A.


    The Blade Reliability Collaborative (BRC) was started by the Wind Energy Technologies Department of Sandia National Laboratories and DOE in 2010 with the goal of gaining insight into planned and unplanned O&M issues associated with wind turbine blades. A significant part of BRC is the Blade Defect, Damage and Repair Survey task, which will gather data from blade manufacturers, service companies, operators and prior studies to determine details about the largest sources of blade unreliability. This report summarizes the initial findings from this work.

  3. Load Control System Reliability

    Trudnowski, Daniel [Montana Tech of the Univ. of Montana, Butte, MT (United States)


    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  4. Supply chain reliability modelling

    Eugen Zaitsev


    Full Text Available Background: Today it is virtually impossible to operate alone on the international level in the logistics business. This promotes the establishment and development of new integrated business entities - logistic operators. However, such cooperation within a supply chain creates also many problems related to the supply chain reliability as well as the optimization of the supplies planning. The aim of this paper was to develop and formulate the mathematical model and algorithms to find the optimum plan of supplies by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Methods: The mathematical model and algorithms to find the optimum plan of supplies were developed and formulated by using economic criterion and the model for the probability evaluating of non-failure operation of supply chain. Results and conclusions: The problem of ensuring failure-free performance of goods supply channel analyzed in the paper is characteristic of distributed network systems that make active use of business process outsourcing technologies. The complex planning problem occurring in such systems that requires taking into account the consumer's requirements for failure-free performance in terms of supply volumes and correctness can be reduced to a relatively simple linear programming problem through logical analysis of the structures. The sequence of the operations, which should be taken into account during the process of the supply planning with the supplier's functional reliability, was presented.

  5. Reliability with imperfect diagnostics. [flight-maintenance sequence

    White, A. L.


    A reliability estimation method for systems that continually accumulate faults because of imperfect diagnostics is developed and an application for redundant digital avionics is presented. The present method assumes that if a fault does not appear in a short period of time, it will remain hidden until a majority of components are faulty and the system fails. A certain proportion of a component's faults are detected in a short period of time, and a description of their detection is included in the reliability model. A Markov model of failure during flight for a nonreconfigurable five-plex is presented for a sequence of one-hour flights followed by maintenance.

  6. OSS reliability measurement and assessment

    Yamada, Shigeru


    This book analyses quantitative open source software (OSS) reliability assessment and its applications, focusing on three major topic areas: the Fundamentals of OSS Quality/Reliability Measurement and Assessment; the Practical Applications of OSS Reliability Modelling; and Recent Developments in OSS Reliability Modelling. Offering an ideal reference guide for graduate students and researchers in reliability for open source software (OSS) and modelling, the book introduces several methods of reliability assessment for OSS including component-oriented reliability analysis based on analytic hierarchy process (AHP), analytic network process (ANP), and non-homogeneous Poisson process (NHPP) models, the stochastic differential equation models and hazard rate models. These measurement and management technologies are essential to producing and maintaining quality/reliable systems using OSS.

  7. Reliability and validity in research.

    Roberts, Paula; Priest, Helena

    This article examines reliability and validity as ways to demonstrate the rigour and trustworthiness of quantitative and qualitative research. The authors discuss the basic principles of reliability and validity for readers who are new to research.

  8. Reliability and Its Quantitative Measures

    Alexandru ISAIC-MANIU


    Full Text Available In this article is made an opening for the software reliability issues, through wide-ranging statistical indicators, which are designed based on information collected from operating or testing (samples. It is developed the reliability issues also for the case of the main reliability laws (exponential, normal, Weibull, which validated for a particular system, allows the calculation of some reliability indicators with a higher degree of accuracy and trustworthiness

  9. 2017 NREL Photovoltaic Reliability Workshop

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)


    NREL's Photovoltaic (PV) Reliability Workshop (PVRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology -- both critical goals for moving PV technologies deeper into the electricity marketplace.

  10. Testing for PV Reliability (Presentation)

    Kurtz, S.; Bansal, S.


    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  11. Reliable Quantum Computers

    Preskill, J


    The new field of quantum error correction has developed spectacularly since its origin less than two years ago. Encoded quantum information can be protected from errors that arise due to uncontrolled interactions with the environment. Recovery from errors can work effectively even if occasional mistakes occur during the recovery procedure. Furthermore, encoded quantum information can be processed without serious propagation of errors. Hence, an arbitrarily long quantum computation can be performed reliably, provided that the average probability of error per quantum gate is less than a certain critical value, the accuracy threshold. A quantum computer storing about 10^6 qubits, with a probability of error per quantum gate of order 10^{-6}, would be a formidable factoring engine. Even a smaller, less accurate quantum computer would be able to perform many useful tasks. (This paper is based on a talk presented at the ITP Conference on Quantum Coherence and Decoherence, 15-18 December 1996.)

  12. Reliability of Pulse Measurements in Videoplethysmography

    Rumiński Jacek


    Full Text Available Reliable, remote pulse rate measurement is potentially very important for medical diagnostics and screening. In this paper the Videoplethysmography was analyzed especially to verify the possible use of signals obtained for the YUV color model in order to estimate the pulse rate, to examine what is the best pulse estimation method for short video sequences and finally, to analyze how potential PPG-signals can be distinguished from other (e.g. background signals. The presented methods were verified using data collected from 60 volunteers.

  13. Fast wafer-level detection and control of interconnect reliability

    Foley, Sean; Molyneaux, James; Mathewson, Alan


    Many of the technological advances in the semiconductor industry have led to dramatic increases in device density and performance in conjunction with enhanced circuit reliability. As reliability is improved, the time taken to characterize particular failure modes with traditional test methods is getting substantially longer. Furthermore, semiconductor customers expect low product cost and fast time-to-market. The limits of traditional reliability testing philosophies are being reached and new approaches need to be investigated to enable the next generation of highly reliable products to be tested. This is especially true in the area of IC interconnect, where significant challenges are predicted for the next decade. A number of fast, wafer level test methods exist for interconnect reliability evaluation. The relative abilities of four such methods to detect the quality and reliability of IC interconnect over very short test times are evaluated in this work. Four different test structure designs are also evaluated and the results are bench-marked against conventional package level Median Time to Failure results. The Isothermal test method combine with SWEAT-type test structures is shown to be the most suitable combination for defect detection and interconnect reliability control over very short test times.

  14. Electronics reliability calculation and design

    Dummer, Geoffrey W A; Hiller, N


    Electronics Reliability-Calculation and Design provides an introduction to the fundamental concepts of reliability. The increasing complexity of electronic equipment has made problems in designing and manufacturing a reliable product more and more difficult. Specific techniques have been developed that enable designers to integrate reliability into their products, and reliability has become a science in its own right. The book begins with a discussion of basic mathematical and statistical concepts, including arithmetic mean, frequency distribution, median and mode, scatter or dispersion of mea

  15. Hybrid reliability model for fatigue reliability analysis of steel bridges

    曹珊珊; 雷俊卿


    A kind of hybrid reliability model is presented to solve the fatigue reliability problems of steel bridges. The cumulative damage model is one kind of the models used in fatigue reliability analysis. The parameter characteristics of the model can be described as probabilistic and interval. The two-stage hybrid reliability model is given with a theoretical foundation and a solving algorithm to solve the hybrid reliability problems. The theoretical foundation is established by the consistency relationships of interval reliability model and probability reliability model with normally distributed variables in theory. The solving process is combined with the definition of interval reliability index and the probabilistic algorithm. With the consideration of the parameter characteristics of theS−N curve, the cumulative damage model with hybrid variables is given based on the standards from different countries. Lastly, a case of steel structure in the Neville Island Bridge is analyzed to verify the applicability of the hybrid reliability model in fatigue reliability analysis based on the AASHTO.

  16. Synthesis of Reliable Telecommunication Networks

    Dusan Trstensky


    Full Text Available In many application, the network designer may to know to senthesise a reliable telecommunication network. Assume that a network, denoted Gm,e has the number of nodes n and the number of edges e, and the operational probability of each edge is known. The system reliability of the network is defined to be the reliability that every pair of nodes can communicate with each other. A network synthesis problem considered in this paper is to find a network G*n,e, that maximises system reliability over the class of all networks for the classes of networks Gn,n-1, Gn,m and Gn,n+1 respectively. In addition an upper bound of maximum reliability for the networks with n-node and e-edge (e>n+2 is derived in terms of node. Computational experiments for the reliability upper are also presented. the results show, that the proposed reliability upper bound is effective.

  17. Mathematical reliability an expository perspective

    Mazzuchi, Thomas; Singpurwalla, Nozer


    In this volume consideration was given to more advanced theoretical approaches and novel applications of reliability to ensure that topics having a futuristic impact were specifically included. Topics like finance, forensics, information, and orthopedics, as well as the more traditional reliability topics were purposefully undertaken to make this collection different from the existing books in reliability. The entries have been categorized into seven parts, each emphasizing a theme that seems poised for the future development of reliability as an academic discipline with relevance. The seven parts are networks and systems; recurrent events; information and design; failure rate function and burn-in; software reliability and random environments; reliability in composites and orthopedics, and reliability in finance and forensics. Embedded within the above are some of the other currently active topics such as causality, cascading, exchangeability, expert testimony, hierarchical modeling, optimization and survival...

  18. Is quantitative electromyography reliable?

    Cecere, F; Ruf, S; Pancherz, H


    The reliability of quantitative electromyography (EMG) of the masticatory muscles was investigated in 14 subjects without any signs or symptoms of temporomandibular disorders. Integrated EMG activity from the anterior temporalis and masseter muscles was recorded bilaterally by means of bipolar surface electrodes during chewing and biting activities. In the first experiment, the influence of electrode relocation was investigated. No influence of electrode relocation on the recorded EMG signal could be detected. In a second experiment, three sessions of EMG recordings during five different chewing and biting activities were performed in the morning (I); 1 hour later without intermediate removal of the electrodes (II); and in the afternoon, using new electrodes (III). The method errors for different time intervals (I-II and I-III errors) for each muscle and each function were calculated. Depending on the time interval between the EMG recordings, the muscles considered, and the function performed, the individual errors ranged from 5% to 63%. The method error increased significantly (P masseter (mean 27.2%) was higher than for the temporalis (mean 20.0%). The largest function error was found during maximal biting in intercuspal position (mean 23.1%). Based on the findings, quantitative electromyography of the masticatory muscles seems to have a limited value in diagnostics and in the evaluation of individual treatment results.

  19. Reliability Assessment Of Wind Turbines

    Sørensen, John Dalsgaard


    Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models...... for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects...... of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed...

  20. Nuclear weapon reliability evaluation methodology

    Wright, D.L. [Sandia National Labs., Albuquerque, NM (United States)


    This document provides an overview of those activities that are normally performed by Sandia National Laboratories to provide nuclear weapon reliability evaluations for the Department of Energy. These reliability evaluations are first provided as a prediction of the attainable stockpile reliability of a proposed weapon design. Stockpile reliability assessments are provided for each weapon type as the weapon is fielded and are continuously updated throughout the weapon stockpile life. The reliability predictions and assessments depend heavily on data from both laboratory simulation and actual flight tests. An important part of the methodology are the opportunities for review that occur throughout the entire process that assure a consistent approach and appropriate use of the data for reliability evaluation purposes.

  1. Reliability engineering theory and practice

    Birolini, Alessandro


    This book shows how to build in, evaluate, and demonstrate reliability and availability of components, equipment, systems. It presents the state-of-theart of reliability engineering, both in theory and practice, and is based on the author's more than 30 years experience in this field, half in industry and half as Professor of Reliability Engineering at the ETH, Zurich. The structure of the book allows rapid access to practical results. This final edition extend and replace all previous editions. New are, in particular, a strategy to mitigate incomplete coverage, a comprehensive introduction to human reliability with design guidelines and new models, and a refinement of reliability allocation, design guidelines for maintainability, and concepts related to regenerative stochastic processes. The set of problems for homework has been extended. Methods & tools are given in a way that they can be tailored to cover different reliability requirement levels and be used for safety analysis. Because of the Appendice...

  2. Lithium battery safety and reliability

    Levy, Samuel C.

    Lithium batteries have been used in a variety of applications for a number of years. As their use continues to grow, particularly in the consumer market, a greater emphasis needs to be placed on safety and reliability. There is a useful technique which can help to design cells and batteries having a greater degree of safety and higher reliability. This technique, known as fault tree analysis, can also be useful in determining the cause of unsafe behavior and poor reliability in existing designs.

  3. Childhood Short Stature

    Ray, J.


    Childhood short stature comprises Varity of endocrinal, systemic, Skeletal & genetic disorders of pediatrics and is not just confined for endocrinal disorder only. A systemic approach often reduces the need for test which is often expensive &unnecessary. Use growth chart & asses bone age during evaluation. Short & heavy child are generally due to Endocrine causes, Short & thin are due to systemic disease, Short with normal velocity are may be due to Constitutional delay in growth &puberty or ...

  4. Short-circuit logic

    Bergstra, J.A.; Ponse, A.


    Short-circuit evaluation denotes the semantics of propositional connectives in which the second argument is only evaluated if the first argument does not suffice to determine the value of the expression. In programming, short-circuit evaluation is widely used. A short-circuit logic is a variant of p

  5. Ultra Reliable Closed Loop Life Support for Long Space Missions

    Jones, Harry W.; Ewert, Michael K.


    Spacecraft human life support systems can achieve ultra reliability by providing sufficient spares to replace all failed components. The additional mass of spares for ultra reliability is approximately equal to the original system mass, provided that the original system reliability is not too low. Acceptable reliability can be achieved for the Space Shuttle and Space Station by preventive maintenance and by replacing failed units. However, on-demand maintenance and repair requires a logistics supply chain in place to provide the needed spares. In contrast, a Mars or other long space mission must take along all the needed spares, since resupply is not possible. Long missions must achieve ultra reliability, a very low failure rate per hour, since they will take years rather than weeks and cannot be cut short if a failure occurs. Also, distant missions have a much higher mass launch cost per kilogram than near-Earth missions. Achieving ultra reliable spacecraft life support systems with acceptable mass will require a well-planned and extensive development effort. Analysis must determine the reliability requirement and allocate it to subsystems and components. Ultra reliability requires reducing the intrinsic failure causes, providing spares to replace failed components and having "graceful" failure modes. Technologies, components, and materials must be selected and designed for high reliability. Long duration testing is needed to confirm very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The system must be designed, developed, integrated, and tested with system reliability in mind. Maintenance and reparability of failed units must not add to the probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass should start soon since it must be a long term effort.

  6. Reliability engineering theory and practice

    Birolini, Alessandro


    Presenting a solid overview of reliability engineering, this volume enables readers to build and evaluate the reliability of various components, equipment and systems. Current applications are presented, and the text itself is based on the author's 30 years of experience in the field.

  7. The Validity of Reliability Measures.

    Seddon, G. M.


    Demonstrates that some commonly used indices can be misleading in their quantification of reliability. The effects are most pronounced on gain or difference scores. Proposals are made to avoid sources of invalidity by using a procedure to assess reliability in terms of upper and lower limits for the true scores of each examinee. (Author/JDH)

  8. Software Reliability through Theorem Proving

    S.G.K. Murthy


    Full Text Available Improving software reliability of mission-critical systems is widely recognised as one of the major challenges. Early detection of errors in software requirements, designs and implementation, need rigorous verification and validation techniques. Several techniques comprising static and dynamic testing approaches are used to improve reliability of mission critical software; however it is hard to balance development time and budget with software reliability. Particularly using dynamic testing techniques, it is hard to ensure software reliability, as exhaustive testing is not possible. On the other hand, formal verification techniques utilise mathematical logic to prove correctness of the software based on given specifications, which in turn improves the reliability of the software. Theorem proving is a powerful formal verification technique that enhances the software reliability for missioncritical aerospace applications. This paper discusses the issues related to software reliability and theorem proving used to enhance software reliability through formal verification technique, based on the experiences with STeP tool, using the conventional and internationally accepted methodologies, models, theorem proving techniques available in the tool without proposing a new model.Defence Science Journal, 2009, 59(3, pp.314-317, DOI:

  9. Reliability engineering in RF CMOS


    In this thesis new developments are presented for reliability engineering in RF CMOS. Given the increase in use of CMOS technology in applications for mobile communication, also the reliability of CMOS for such applications becomes increasingly important. When applied in these applications, CMOS is typically referred to as RF CMOS, where RF stands for radio frequencies.

  10. Reliability in automotive ethernet networks

    Soares, Fabio L.; Campelo, Divanilson R.; Yan, Ying;


    This paper provides an overview of in-vehicle communication networks and addresses the challenges of providing reliability in automotive Ethernet in particular.......This paper provides an overview of in-vehicle communication networks and addresses the challenges of providing reliability in automotive Ethernet in particular....

  11. Estimation of Bridge Reliability Distributions

    Thoft-Christensen, Palle

    In this paper it is shown how the so-called reliability distributions can be estimated using crude Monte Carlo simulation. The main purpose is to demonstrate the methodology. Therefor very exact data concerning reliability and deterioration are not needed. However, it is intended in the paper to ...

  12. Fatigue reliability of cracked engineering structures

    Lanning, David Bruce, Jr.


    This study investigates the reliability of engineering structures containing fatigue cracks. Stress concentrations and welded joints are probable locations for the initiation and propagation of fatigue cracks. Due to the many unknowns of loading, materials properties, crack sizes and crack shapes present at these locations, a statistics-based reliability analysis is valuable in the careful consideration of these many different random factors involved in a fatigue life analysis, several of which are expanded upon in this study. The basic problem of a crack near a stress concentration is first considered. A formulation for the aspect ratio (a/c) of a propagating semi-elliptical fatigue crack located at the toe of a welded T-joint is developed using Newman and Raju's stress intensity factor for a cracked flat plate with a weld magnification factor and compared to that of a cracked flat plate, and the reliability in terms of fatigue lifetime is calculated with the aid of Paris' crack propagation equation for membrane and bending loadings. Crack closure effects are then introduced in the consideration of short crack effects, where crack growth rates typically may exceed those found using traditional linear elastic fracture mechanics solutions for long cracks. The probability of a very small, microstructurally influenced crack growing to a size influenced by local plastic conditions is calculated utilizing the probability of a crack continuing to grow past an obstacle, such as a grain boundary. The result is then combined with the probability for failure defined using the crack closure-modified Paris equation to find an overall reliability for the structure. Last, the probability of fracture is determined when a crack front encounters regions of non-uniform toughness, such as typical in the heat affected zone of a welded joint. An expression for the effective crack lengths of the dissimilar regions is derived, and used in a weakest-link fracture model in the evaluation


    B.Anni Princy


    Full Text Available A software reliability exemplary projects snags the random process as disillusionments which were the culmination yield of two progressions: emerging faults and initial state values. The predominant classification uses the logistic analysis effort function mounting efficient software on the real time dataset. The detriments of the logistic testing were efficaciously overcome by Pareto distribution. The estimated outline ventures the resolved technique for analyzing the suitable communities and the preeminent of fit for a software reliability progress model. Its constraints are predictable to evaluate the reliability of a software system. The future process will permit for software reliability estimations that can be used both as prominence Indicator, but also for planning and controlling resources, the development times based on the onslaught assignments of the efficient computing and reliable measurement of a software system was competent.

  14. Reliability estimation using kriging metamodel

    Cho, Tae Min; Ju, Byeong Hyeon; Lee, Byung Chai [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Jung, Do Hyun [Korea Automotive Technology Institute, Chonan (Korea, Republic of)


    In this study, the new method for reliability estimation is proposed using kriging metamodel. Kriging metamodel can be determined by appropriate sampling range and sampling numbers because there are no random errors in the Design and Analysis of Computer Experiments(DACE) model. The first kriging metamodel is made based on widely ranged sampling points. The Advanced First Order Reliability Method(AFORM) is applied to the first kriging metamodel to estimate the reliability approximately. Then, the second kriging metamodel is constructed using additional sampling points with updated sampling range. The Monte-Carlo Simulation(MCS) is applied to the second kriging metamodel to evaluate the reliability. The proposed method is applied to numerical examples and the results are almost equal to the reference reliability.

  15. Reliability-Based Code Calibration

    Faber, M.H.; Sørensen, John Dalsgaard


    The present paper addresses fundamental concepts of reliability based code calibration. First basic principles of structural reliability theory are introduced and it is shown how the results of FORM based reliability analysis may be related to partial safety factors and characteristic values....... Thereafter the code calibration problem is presented in its principal decision theoretical form and it is discussed how acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for ultimate...... and serviceability limit states. Finally the paper describes the Joint Committee on Structural Safety (JCSS) recommended procedure - CodeCal - for the practical implementation of reliability based code calibration of LRFD based design codes....

  16. Photovoltaic performance and reliability workshop

    Mrig, L. [ed.


    This workshop was the sixth in a series of workshops sponsored by NREL/DOE under the general subject of photovoltaic testing and reliability during the period 1986--1993. PV performance and PV reliability are at least as important as PV cost, if not more. In the US, PV manufacturers, DOE laboratories, electric utilities, and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in the field were brought together to exchange the technical knowledge and field experience as related to current information in this evolving field of PV reliability. The papers presented here reflect this effort since the last workshop held in September, 1992. The topics covered include: cell and module characterization, module and system testing, durability and reliability, system field experience, and standards and codes.

  17. Contributors to Surgical In-patient Satisfaction—Development and Reliability of a Targeted Instrument

    CSK Cheung


    Conclusions: The initial version of HK2Happ was reliable in assessing surgical patient satisfaction. The measure is now undergoing validity testing across different surgical patient populations for generalisation and generation of a short form of discriminant items.

  18. Robust Design of Reliability Test Plans Using Degradation Measures.

    Lane, Jonathan Wesley; Lane, Jonathan Wesley; Crowder, Stephen V.; Crowder, Stephen V.


    With short production development times, there is an increased need to demonstrate product reliability relatively quickly with minimal testing. In such cases there may be few if any observed failures. Thus, it may be difficult to assess reliability using the traditional reliability test plans that measure only time (or cycles) to failure. For many components, degradation measures will contain important information about performance and reliability. These measures can be used to design a minimal test plan, in terms of number of units placed on test and duration of the test, necessary to demonstrate a reliability goal. Generally, the assumption is made that the error associated with a degradation measure follows a known distribution, usually normal, although in practice cases may arise where that assumption is not valid. In this paper, we examine such degradation measures, both simulated and real, and present non-parametric methods to demonstrate reliability and to develop reliability test plans for the future production of components with this form of degradation.

  19. Electronic parts reliability data 1997

    Denson, William; Jaworski, Paul; Mahar, David


    This document contains reliability data on both commercial and military electronic components for use in reliability analyses. It contains failure rate data on integrated circuits, discrete semiconductors (diodes, transistors, optoelectronic devices), resistors, capacitors, and inductors/transformers, all of which were obtained from the field usage of electronic components. At 2,000 pages, the format of this document is the same as RIAC's popular NPRD document which contains reliability data on nonelectronic component and electronic assembly types. Data includes part descriptions, quality level, application environments, point estimates of failure rate, data sources, number of failures, total operating hours, miles, or cycles, and detailed part characteristics.

  20. [Short lingual frenulum].

    Klockars, Tuomas


    Short lingual frenulum is a common structural abnormality with unknown mechanisms of origination. The frequency of occurrence among newborn infants can be as high as 4%. Short lingual frenulum may cause problems, if it restricts the movements of the tongue. Therapeutic indications for short lingual frenulum in newborn infants are mainly breastfeeding problems, whereas in children of preschool age and older the indication is defective pronunciation.

  1. Long and short GRB

    Katz, J I


    We report evidence from the 3B Catalogue that short (T_90 10 s) GRB represent different populations and processes: Their spectral behavior is qualitatively different, with short bursts harder in the BATSE range, but chiefly long bursts detected at higher photon energies; \\langle V/V_max \\rangle = 0.385 \\pm 0.019 for short GRB but \\langle V/V_max \\rangle = 0.282 \\pm 0.014 for long GRB, differing by 0.103 \\pm 0.024. Long GRB may be the consequence of accretion-induced collapse, but this mechanism fails for short GRB, for which we suggest colliding neutron stars.

  2. Reliability Modeling of Wind Turbines

    Kostandyan, Erik

    and uncertainties are quantified. Further, estimation of annual failure probability for structural components taking into account possible faults in electrical or mechanical systems is considered. For a representative structural failure mode, a probabilistic model is developed that incorporates grid loss failures...... components. Thus, models of reliability should be developed and applied in order to quantify the residual life of the components. Damage models based on physics of failure combined with stochastic models describing the uncertain parameters are imperative for development of cost-optimal decision tools...... for Operation & Maintenance planning. Concentrating efforts on development of such models, this research is focused on reliability modeling of Wind Turbine critical subsystems (especially the power converter system). For reliability assessment of these components, structural reliability methods are applied...

  3. Reliability Analysis of Wind Turbines

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard


    In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states...... consideres are in the ultimate limit state (ULS) extreme conditions in the standstill position and extreme conditions during operating. For wind turbines, where the magnitude of the loads is influenced by the control system, the ultimate limit state can occur in both cases. In the fatigue limit state (FLS......) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according...

  4. Reliability analysis in intelligent machines

    Mcinroy, John E.; Saridis, George N.


    Given an explicit task to be executed, an intelligent machine must be able to find the probability of success, or reliability, of alternative control and sensing strategies. By using concepts for information theory and reliability theory, new techniques for finding the reliability corresponding to alternative subsets of control and sensing strategies are proposed such that a desired set of specifications can be satisfied. The analysis is straightforward, provided that a set of Gaussian random state variables is available. An example problem illustrates the technique, and general reliability results are presented for visual servoing with a computed torque-control algorithm. Moreover, the example illustrates the principle of increasing precision with decreasing intelligence at the execution level of an intelligent machine.

  5. Reliability Assessment of Wind Turbines

    Sørensen, John Dalsgaard


    (and safe). In probabilistic design the single components are designed to a level of reliability, which accounts for an optimal balance between failure consequences, cost of operation & maintenance, material costs and the probability of failure. Furthermore, using a probabilistic design basis...... but manufactured in series production based on many component tests, some prototype tests and zeroseries wind turbines. These characteristics influence the reliability assessment where focus in this paper is on the structural components. Levelized Cost Of Energy is very important for wind energy, especially when...... comparing to other energy sources. Therefore much focus is on cost reductions and improved reliability both for offshore and onshore wind turbines. The wind turbine components should be designed to have sufficient reliability level with respect to both extreme and fatigue loads but also not be too costly...

  6. On Bayesian System Reliability Analysis

    Soerensen Ringi, M.


    The view taken in this thesis is that reliability, the probability that a system will perform a required function for a stated period of time, depends on a person`s state of knowledge. Reliability changes as this state of knowledge changes, i.e. when new relevant information becomes available. Most existing models for system reliability prediction are developed in a classical framework of probability theory and they overlook some information that is always present. Probability is just an analytical tool to handle uncertainty, based on judgement and subjective opinions. It is argued that the Bayesian approach gives a much more comprehensive understanding of the foundations of probability than the so called frequentistic school. A new model for system reliability prediction is given in two papers. The model encloses the fact that component failures are dependent because of a shared operational environment. The suggested model also naturally permits learning from failure data of similar components in non identical environments. 85 refs.

  7. VCSEL reliability: a user's perspective

    McElfresh, David K.; Lopez, Leoncio D.; Melanson, Robert; Vacar, Dan


    VCSEL arrays are being considered for use in interconnect applications that require high speed, high bandwidth, high density, and high reliability. In order to better understand the reliability of VCSEL arrays, we initiated an internal project at SUN Microsystems, Inc. In this paper, we present preliminary results of an ongoing accelerated temperature-humidity-bias stress test on VCSEL arrays from several manufacturers. This test revealed no significant differences between the reliability of AlGaAs, oxide confined VCSEL arrays constructed with a trench oxide and mesa for isolation. This test did find that the reliability of arrays needs to be measured on arrays and not be estimated with the data from singulated VCSELs as is a common practice.

  8. Innovations in power systems reliability

    Santora, Albert H; Vaccaro, Alfredo


    Electrical grids are among the world's most reliable systems, yet they still face a host of issues, from aging infrastructure to questions of resource distribution. Here is a comprehensive and systematic approach to tackling these contemporary challenges.

  9. Accelerator Availability and Reliability Issues

    Steve Suhring


    Maintaining reliable machine operations for existing machines as well as planning for future machines' operability present significant challenges to those responsible for system performance and improvement. Changes to machine requirements and beam specifications often reduce overall machine availability in an effort to meet user needs. Accelerator reliability issues from around the world will be presented, followed by a discussion of the major factors influencing machine availability.

  10. Software Reliability Experimentation and Control

    Kai-Yuan Cai


    This paper classifies software researches as theoretical researches, experimental researches, and engineering researches, and is mainly concerned with the experimental researches with focus on software reliability experimentation and control. The state-of-the-art of experimental or empirical studies is reviewed. A new experimentation methodology is proposed, which is largely theory discovering oriented. Several unexpected results of experimental studies are presented to justify the importance of software reliability experimentation and control. Finally, a few topics that deserve future investigation are identified.

  11. MEMS reliability: coming of age

    Douglass, Michael R.


    In today's high-volume semiconductor world, one could easily take reliability for granted. As the MOEMS/MEMS industry continues to establish itself as a viable alternative to conventional manufacturing in the macro world, reliability can be of high concern. Currently, there are several emerging market opportunities in which MOEMS/MEMS is gaining a foothold. Markets such as mobile media, consumer electronics, biomedical devices, and homeland security are all showing great interest in microfabricated products. At the same time, these markets are among the most demanding when it comes to reliability assurance. To be successful, each company developing a MOEMS/MEMS device must consider reliability on an equal footing with cost, performance and manufacturability. What can this maturing industry learn from the successful development of DLP technology, air bag accelerometers and inkjet printheads? This paper discusses some basic reliability principles which any MOEMS/MEMS device development must use. Examples from the commercially successful and highly reliable Digital Micromirror Device complement the discussion.

  12. Childhood Short Stature



    Full Text Available Childhood short stature comprises Varity of endocrinal, systemic, Skeletal & genetic disorders of pediatrics and is not just confined for endocrinal disorder only. A systemic approach often reduces the need for test which is often expensive &unnecessary. Use growth chart & asses bone age during evaluation. Short & heavy child are generally due to Endocrine causes, Short & thin are due to systemic disease, Short with normal velocity are may be due to Constitutional delay in growth &puberty or Familial short stature, differentiation can be done by Bone Age. In Girls Turner syndrome has to be kept in mind. Purpose of evaluation to find out the child who does not need treatment, who cannot be treated & the child who can be benefited from treatment.

  13. Idiopathic short stature

    Vlaški Jovan


    Full Text Available Growth is a complex process and the basic characteristic of child- hood growth monitoring provides insight into the physiological and pathological events in the body. Statistically, the short stature means departure from the values of height for age and sex (in a particular environment, which is below -2 standard deviation score, or less than -2 standard deviation, i.e. below the third percentile. Advances in molecular genetics have contributed to the improvement of diagnostics in endocrinology. Analysis of patients’ genotypes should not be performed before taking a classical history, detailed clinical examination and appropriate tests. In patients with idiopathic short stature specific causes are excluded, such as growth hormone deficiency, Turner syndrome, short stature due to low birth weight, intrauterine growth retardation, small for gestational age, dysmorphology syndromes and chronic childhood diseases. The exclusion of abovementioned conditions leaves a large number of children with short stature whose etiology includes patients with genetic short stature or familial short stature and those who are low in relation to genetic potential, and who could also have some unrecognized endocrine defect. Idiopathic short stature represents a short stature of unknown cause of heterogeneous etiology, and is characterized by a normal response of growth hormone during stimulation tests (>10 ng/ml or 20 mJ/l, without other disorders, of normal body mass and length at birth. In idiopathic short stature standard deviation score rates <-2.25 (-2 to -3 or <1.2 percentile. These are also criteria for the initiation of growth hormone therapy. In children with short stature there is also the presence of psychological and social suffering. Goals of treatment with growth hormone involve achieving normal height and normal growth rate during childhood.

  14. Reliability of plantar pressure platforms.

    Hafer, Jocelyn F; Lenhoff, Mark W; Song, Jinsup; Jordan, Joanne M; Hannan, Marian T; Hillstrom, Howard J


    Plantar pressure measurement is common practice in many research and clinical protocols. While the accuracy of some plantar pressure measuring devices and methods for ensuring consistency in data collection on plantar pressure measuring devices have been reported, the reliability of different devices when testing the same individuals is not known. This study calculated intra-mat, intra-manufacturer, and inter-manufacturer reliability of plantar pressure parameters as well as the number of plantar pressure trials needed to reach a stable estimate of the mean for an individual. Twenty-two healthy adults completed ten walking trials across each of two Novel emed-x(®) and two Tekscan MatScan(®) plantar pressure measuring devices in a single visit. Intraclass correlation (ICC) was used to describe the agreement between values measured by different devices. All intra-platform reliability correlations were greater than 0.70. All inter-emed-x(®) reliability correlations were greater than 0.70. Inter-MatScan(®) reliability correlations were greater than 0.70 in 31 and 52 of 56 parameters when looking at a 10-trial average and a 5-trial average, respectively. Inter-manufacturer reliability including all four devices was greater than 0.70 for 52 and 56 of 56 parameters when looking at a 10-trial average and a 5-trial average, respectively. All parameters reached a value within 90% of an unbiased estimate of the mean within five trials. Overall, reliability results are encouraging for investigators and clinicians who may have plantar pressure data sets that include data collected on different devices.

  15. 78 FR 38311 - Reliability Technical Conference Agenda


    ..., Fix, Track, and Report program enhanced reliability? b. What is the status of the NERC Reliability... Energy Regulatory Commission Reliability Technical Conference Agenda Reliability Technical Docket No. AD13-6-000 Conference. North American Electric Docket No. RC11-6-004 Reliability Corporation....

  16. Congenital short pancreas

    DU Juan; XU Guo-qiang; XU Ping; JIN En-yun; LIU Qiong; LI You-ming


    @@ Congenital short pancreas, also known as partial agenesis or hypoplasia of the dorsal pancreas1 is a rare congenital abnormality consisting of the parenchyma and ductal system restricted to the head with some residual dorsal tapering and arborizing ducts communicating with the minor papill.2 Complete pancreatic agenesis is fatal, and only nine possible examples of partial agenesis have been previously reported in adults in the literature.3-10 Three of them were polysplenia syndrome associated with short pancreas,and only six patients with congenital short pancreas with normal situs. Here we present a new case associated with steatorrhoea.

  17. Imaging in short stature

    Vikas Chaudhary


    Full Text Available Short stature can be a sign of disease, disability, and social stigma causing psychological stress. It is important to have an early diagnosis and treatment. Short stature may result from skeletal dysplasias, endocrine disorders, may be familial, or may be the result of malnutrition and chronic illnesses. A team effort of the healthcare professionals like pediatricians, endocrinologists, radiologists, and pathologists is required to diagnose, treat and monitor various pathological conditions associated with growth abnormality. In this review, we have discussed the role of imaging in diagnosing and characterizing various pathological conditions associated with short stature.

  18. Reliability Based Ship Structural Design

    Dogliani, M.; Østergaard, C.; Parmentier, G.;


    with developments of models of load effects and of structural collapse adopted in reliability formulations which aim at calibrating partial safety factors for ship structural design. New probabilistic models of still-water load effects are developed both for tankers and for containerships. New results are presented......This paper deals with the development of different methods that allow the reliability-based design of ship structures to be transferred from the area of research to the systematic application in current design. It summarises the achievements of a three-year collaborative research project dealing...... structure of several tankers and containerships. The results of the reliability analysis were the basis for the definition of a target safety level which was used to asses the partial safety factors suitable for in a new design rules format to be adopted in modern ship structural design. Finally...

  19. Reliability Modeling of Wind Turbines

    Kostandyan, Erik

    Cost reductions for offshore wind turbines are a substantial requirement in order to make offshore wind energy more competitive compared to other energy supply methods. During the 20 – 25 years of wind turbines useful life, Operation & Maintenance costs are typically estimated to be a quarter...... the actions should be made and the type of actions requires knowledge on the accumulated damage or degradation state of the wind turbine components. For offshore wind turbines, the action times could be extended due to weather restrictions and result in damage or degradation increase of the remaining...... for Operation & Maintenance planning. Concentrating efforts on development of such models, this research is focused on reliability modeling of Wind Turbine critical subsystems (especially the power converter system). For reliability assessment of these components, structural reliability methods are applied...

  20. Reliability Assessment of Wind Turbines

    Sørensen, John Dalsgaard


    Wind turbines can be considered as structures that are in between civil engineering structures and machines since they consist of structural components and many electrical and machine components together with a control system. Further, a wind turbine is not a one-of-a-kind structure...... but manufactured in series production based on many component tests, some prototype tests and zeroseries wind turbines. These characteristics influence the reliability assessment where focus in this paper is on the structural components. Levelized Cost Of Energy is very important for wind energy, especially when...... comparing to other energy sources. Therefore much focus is on cost reductions and improved reliability both for offshore and onshore wind turbines. The wind turbine components should be designed to have sufficient reliability level with respect to both extreme and fatigue loads but also not be too costly...

  1. Reliability assessment of Wind turbines

    Sørensen, John Dalsgaard


    Wind turbines can be considered as structures that are in between civil engineering structures and machines since they consist of structural components and many electrical and machine components together with a control system. Further, a wind turbine is not a one-of-a-kind structure...... but manufactured in series production based on many component tests, some prototype tests and zeroseries wind turbines. These characteristics influence the reliability assessment where focus in this paper is on the structural components. Levelized Cost Of Energy is very important for wind energy, especially when...... comparing to other energy sources. Therefore much focus is on cost reductions and improved reliability both for offshore and onshore wind turbines. The wind turbine components should be designed to have sufficient reliability level with respect to both extreme and fatigue loads but also not be too costly...

  2. Reliability of Wave Energy Converters

    Ambühl, Simon

    . Structural reliability considerations and optimizations impact operation and maintenance (O&M) costs as well as the initial investment costs. Furthermore, there is a control system for WEC applications which defines the harvested energy but also the loads onto the structure. Therefore, extreme loads but also...... WEPTOS. Calibration of safety factors are performed for welded structures at theWavestar device including different control systems for harvesting energy from waves. In addition, a case study of different O&M strategies for WECs is discussed, and an example of reliability-based structural optimization......There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs to become successful and more competitive to other renewable electricity sources, the consideration of the structural reliability of WECs is essential...

  3. Reliability Characteristics of Power Plants

    Zbynek Martinek


    Full Text Available This paper describes the phenomenon of reliability of power plants. It gives an explanation of the terms connected with this topic as their proper understanding is important for understanding the relations and equations which model the possible real situations. The reliability phenomenon is analysed using both the exponential distribution and the Weibull distribution. The results of our analysis are specific equations giving information about the characteristics of the power plants, the mean time of operations and the probability of failure-free operation. Equations solved for the Weibull distribution respect the failures as well as the actual operating hours. Thanks to our results, we are able to create a model of dynamic reliability for prediction of future states. It can be useful for improving the current situation of the unit as well as for creating the optimal plan of maintenance and thus have an impact on the overall economics of the operation of these power plants.

  4. Component reliability for electronic systems

    Bajenescu, Titu-Marius I


    The main reason for the premature breakdown of today's electronic products (computers, cars, tools, appliances, etc.) is the failure of the components used to build these products. Today professionals are looking for effective ways to minimize the degradation of electronic components to help ensure longer-lasting, more technically sound products and systems. This practical book offers engineers specific guidance on how to design more reliable components and build more reliable electronic systems. Professionals learn how to optimize a virtual component prototype, accurately monitor product reliability during the entire production process, and add the burn-in and selection procedures that are the most appropriate for the intended applications. Moreover, the book helps system designers ensure that all components are correctly applied, margins are adequate, wear-out failure modes are prevented during the expected duration of life, and system interfaces cannot lead to failure.

  5. New Approaches to Reliability Assessment

    Ma, Ke; Wang, Huai; Blaabjerg, Frede


    of energy. New approaches for reliability assessment are being taken in the design phase of power electronics systems based on the physics-of-failure in components. In this approach, many new methods, such as multidisciplinary simulation tools, strength testing of components, translation of mission profiles......Power electronics are facing continuous pressure to be cheaper and smaller, have a higher power density, and, in some cases, also operate at higher temperatures. At the same time, power electronics products are expected to have reduced failures because it is essential for reducing the cost......, and statistical analysis, are involved to enable better prediction and design of reliability for products. This article gives an overview of the new design flow in the reliability engineering of power electronics from the system-level point of view and discusses some of the emerging needs for the technology...

  6. Structural Optimization with Reliability Constraints

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle


    During the last 25 years considerable progress has been made in the fields of structural optimization and structural reliability theory. In classical deterministic structural optimization all variables are assumed to be deterministic. Due to the unpredictability of loads and strengths of actual...... structures it is now widely accepted that structural problems are non-deterministic. Therefore, some of the variables have to be modelled as random variables/processes and a reliability-based design philosophy should be used, Comell [1], Moses [2], Ditlevsen [3] and Thoft-Christensen & Baker [ 4......]. In this paper we consider only structures which can be modelled as systems of elasto-plastic elements, e.g. frame and truss structures. In section 2 a method to evaluate the reliability of such structural systems is presented. Based on a probabilistic point of view a modern structural optimization problem...

  7. Reliability-based optimization of engineering structures

    Sørensen, John Dalsgaard


    The theoretical basis for reliability-based structural optimization within the framework of Bayesian statistical decision theory is briefly described. Reliability-based cost benefit problems are formulated and exemplitied with structural optimization. The basic reliability-based optimization prob...

  8. Minimizing Shortness of Breath

    ... is also placed on proper use of the abdominal muscles to better control episodes of shortness of breath, ... Treatment & Programs Health Insights Doctors & Departments Research & Science Education & Training Make a Donation Make an Appointment Contact ...

  9. Short-cut math

    Kelly, Gerard W


    Clear, concise compendium of about 150 time-saving math short-cuts features faster, easier ways to add, subtract, multiply, and divide. Each problem includes an explanation of the method. No special math ability needed.

  10. Shortness of Breath

    ... shortness of breath with physical exertion beyond your customary activity such as when climbing stairs. Allergic Reactions ... 75231 Copyright © 2014 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524- ...

  11. Metrological Reliability of Medical Devices

    Costa Monteiro, E.; Leon, L. F.


    The prominent development of health technologies of the 20th century triggered demands for metrological reliability of physiological measurements comprising physical, chemical and biological quantities, essential to ensure accurate and comparable results of clinical measurements. In the present work, aspects concerning metrological reliability in premarket and postmarket assessments of medical devices are discussed, pointing out challenges to be overcome. In addition, considering the social relevance of the biomeasurements results, Biometrological Principles to be pursued by research and innovation aimed at biomedical applications are proposed, along with the analysis of their contributions to guarantee the innovative health technologies compliance with the main ethical pillars of Bioethics.

  12. Reliability Assessment of Concrete Bridges

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  13. Reliability Management for Information System

    李睿; 俞涛; 刘明伦


    An integrated intelligent management is presented to help organizations manage many heterogeneous resources in their information system. A general architecture of management for information system reliability is proposed, and the architecture from two aspects, process model and hierarchical model, described. Data mining techniques are used in data analysis. A data analysis system applicable to real-time data analysis is developed by improved data mining on the critical processes. The framework of the integrated management for information system reliability based on real-time data mining is illustrated, and the development of integrated and intelligent management of information system discussed.

  14. Power system reliability enhancement by using PowerformerTM

    Rahmat-Allah Hooshmand


    Full Text Available A high-voltage generator PowerformerTM is a new generation of the AC generators. The most significant advantages of these PowerformerTM are their direct connection to high-voltage grid, higher availability, and more reactive power margin, short term overloading capacity and removing the power transformer from the structure of the power plant. In this paper, the installation effect of these generators on the power system reliability is investigated. The amount of the effects depends on the type and location of the power plant, location of the PowerformerTM, the size of load and network topology. For this purpose, in the 6-bus IEEE RBTS system, the conventional generators are replaced by these new PowerformerTM and then, the reliability indices are evaluated. The simulation results show that the reliability indices such as the expected duration of load curtailment (EDLC and the expected energy not served (EENS are improved. .

  15. CMOS reliability issues for emerging cryogenic Lunar electronics applications

    Chen, Tianbing; Zhu, Chendong; Najafizadeh, Laleh; Jun, Bongim; Ahmed, Adnan; Diestelhorst, Ryan; Espinel, Gustavo; Cressler, John D.


    We investigate the reliability issues associated with the application of CMOS devices contained within an advanced SiGe HBT BiCMOS technology to emerging cryogenic space electronics (e.g., down to 43 K, for Lunar missions). Reduced temperature operation improves CMOS device performance (e.g., transconductance, carrier mobility, subthreshold swing, and output current drive), as expected. However, operation at cryogenic temperatures also causes serious device reliability concerns, since it aggravates hot-carrier effects, effectively decreasing the inferred device lifetime significantly, especially at short gate lengths. In the paper, hot-carrier effects are demonstrated to be a stronger function of the device gate length than the temperature, suggesting that significant trade-offs between the gate length and the operational temperature must be made in order to ensure safe and reliable operation over typical projected mission lifetimes in these hostile environments.



  17. Reliability of quantitative content analyses

    Enschot-van Dijk, R. van


    Reliable coding of stimuli is a daunting task that often yields unsatisfactory results. This paper discusses a case study in which tropes (e.g., metaphors, puns) in TV commercials were analyzed as well the extent and location of verbal and visual anchoring (i.e., explanation) of these tropes. After

  18. Wind turbine reliability database update.

    Peters, Valerie A.; Hill, Roger Ray; Stinebaugh, Jennifer A.; Veers, Paul S.


    This report documents the status of the Sandia National Laboratories' Wind Plant Reliability Database. Included in this report are updates on the form and contents of the Database, which stems from a fivestep process of data partnerships, data definition and transfer, data formatting and normalization, analysis, and reporting. Selected observations are also reported.

  19. Photovoltaic performance and reliability workshop

    Kroposki, B


    This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activities to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field experience on modules, inverters, batteries, and charge controllers from field deployed PV systems; and system certification and standardized testing for stand-alone and grid-tied systems.


    Dr Obe

    Evaluation of the reliability of a primary cell took place in three stages: 192 cells went through a ... CCV - Closed Circuit Voltage, the voltage at the terminals of a battery when it is under an electrical ... Cylindrical spirally wound cells have the.

  1. Finding Reliable Health Information Online

    ... at NHGRI About About the Institute Budget and Financial Information Divisions Director's Page How to Contact Us Institute ... una búsqueda saludable en Internet Finding Reliable Health Information Online As Internet users quickly discover, an enormous amount of health information ...

  2. Reliability of subjective wound assessment

    M.C.T. Bloemen; P.P.M. van Zuijlen; E. Middelkoop


    Introduction: Assessment of the take of split-skin graft and the rate of epithelialisation are important parameters in burn surgery. Such parameters are normally estimated by the clinician in a bedside procedure. This study investigates whether this subjective assessment is reliable for graft take a

  3. Fatigue Reliability under Random Loads

    Talreja, R.


    , with the application of random loads, the initial homogeneous distribution of strength changes to a two-component distribution, reflecting the two-stage fatigue damage. In the crack initiation stage, the strength increases initially and then decreases, while an abrupt decrease of strength is seen in the crack...... propagation stage. The consequences of this behaviour on the fatigue reliability are discussed....

  4. Reliability Analysis of Money Habitudes

    Delgadillo, Lucy M.; Bushman, Brittani S.


    Use of the Money Habitudes exercise has gained popularity among various financial professionals. This article reports on the reliability of this resource. A survey administered to young adults at a western state university was conducted, and each Habitude or "domain" was analyzed using Cronbach's alpha procedures. Results showed all six…

  5. The Reliability of College Grades

    Beatty, Adam S.; Walmsley, Philip T.; Sackett, Paul R.; Kuncel, Nathan R.; Koch, Amanda J.


    Little is known about the reliability of college grades relative to how prominently they are used in educational research, and the results to date tend to be based on small sample studies or are decades old. This study uses two large databases (N > 800,000) from over 200 educational institutions spanning 13 years and finds that both first-year…

  6. Reliability Analysis of Money Habitudes

    Delgadillo, Lucy M.; Bushman, Brittani S.


    Use of the Money Habitudes exercise has gained popularity among various financial professionals. This article reports on the reliability of this resource. A survey administered to young adults at a western state university was conducted, and each Habitude or "domain" was analyzed using Cronbach's alpha procedures. Results showed all six…

  7. Inflection points for network reliability

    Brown, J.I.; Koç, Y.; Kooij, R.E.


    Given a finite, undirected graph G (possibly with multiple edges), we assume that the vertices are operational, but the edges are each independently operational with probability p. The (all-terminal) reliability, Rel(G,p), of G is the probability that the spanning subgraph of operational edges is co

  8. Becoming a high reliability organization.

    Christianson, Marlys K; Sutcliffe, Kathleen M; Miller, Melissa A; Iwashyna, Theodore J


    Aircraft carriers, electrical power grids, and wildland firefighting, though seemingly different, are exemplars of high reliability organizations (HROs)--organizations that have the potential for catastrophic failure yet engage in nearly error-free performance. HROs commit to safety at the highest level and adopt a special approach to its pursuit. High reliability organizing has been studied and discussed for some time in other industries and is receiving increasing attention in health care, particularly in high-risk settings like the intensive care unit (ICU). The essence of high reliability organizing is a set of principles that enable organizations to focus attention on emergent problems and to deploy the right set of resources to address those problems. HROs behave in ways that sometimes seem counterintuitive--they do not try to hide failures but rather celebrate them as windows into the health of the system, they seek out problems, they avoid focusing on just one aspect of work and are able to see how all the parts of work fit together, they expect unexpected events and develop the capability to manage them, and they defer decision making to local frontline experts who are empowered to solve problems. Given the complexity of patient care in the ICU, the potential for medical error, and the particular sensitivity of critically ill patients to harm, high reliability organizing principles hold promise for improving ICU patient care.

  9. Power Quality and Reliability Project

    Attia, John O.


    One area where universities and industry can link is in the area of power systems reliability and quality - key concepts in the commercial, industrial and public sector engineering environments. Prairie View A&M University (PVAMU) has established a collaborative relationship with the University of'Texas at Arlington (UTA), NASA/Johnson Space Center (JSC), and EP&C Engineering and Technology Group (EP&C) a small disadvantage business that specializes in power quality and engineering services. The primary goal of this collaboration is to facilitate the development and implementation of a Strategic Integrated power/Systems Reliability and Curriculum Enhancement Program. The objectives of first phase of this work are: (a) to develop a course in power quality and reliability, (b) to use the campus of Prairie View A&M University as a laboratory for the study of systems reliability and quality issues, (c) to provide students with NASA/EPC shadowing and Internship experience. In this work, a course, titled "Reliability Analysis of Electrical Facilities" was developed and taught for two semesters. About thirty seven has benefited directly from this course. A laboratory accompanying the course was also developed. Four facilities at Prairie View A&M University were surveyed. Some tests that were performed are (i) earth-ground testing, (ii) voltage, amperage and harmonics of various panels in the buildings, (iii) checking the wire sizes to see if they were the right size for the load that they were carrying, (iv) vibration tests to test the status of the engines or chillers and water pumps, (v) infrared testing to the test arcing or misfiring of electrical or mechanical systems.

  10. Reliability of Arctic offshore installations

    Bercha, F.G. [Bercha Group, Calgary, AB (Canada); Gudmestad, O.T. [Stavanger Univ., Stavanger (Norway)]|[Statoil, Stavanger (Norway)]|[Norwegian Univ. of Technology, Stavanger (Norway); Foschi, R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Civil Engineering; Sliggers, F. [Shell International Exploration and Production, Rijswijk (Netherlands); Nikitina, N. [VNIIG, St. Petersburg (Russian Federation); Nevel, D.


    Life threatening and fatal failures of offshore structures can be attributed to a broad range of causes such as fires and explosions, buoyancy losses, and structural overloads. This paper addressed the different severities of failure types, categorized as catastrophic failure, local failure or serviceability failure. Offshore tragedies were also highlighted, namely the failures of P-36, the Ocean Ranger, the Piper Alpha, and the Alexander Kieland which all resulted in losses of human life. P-36 and the Ocean Ranger both failed ultimately due to a loss of buoyancy. The Piper Alpha was destroyed by a natural gas fire, while the Alexander Kieland failed due to fatigue induced structural failure. The mode of failure was described as being the specific way in which a failure occurs from a given cause. Current reliability measures in the context of offshore installations only consider the limited number of causes such as environmental loads. However, it was emphasized that a realistic value of the catastrophic failure probability should consider all credible causes of failure. This paper presented a general method for evaluating all credible causes of failure of an installation. The approach to calculating integrated reliability involves the use of network methods such as fault trees to combine the probabilities of all factors that can cause a catastrophic failure, as well as those which can cause a local failure with the potential to escalate to a catastrophic failure. This paper also proposed a protocol for setting credible reliability targets such as the consideration of life safety targets and escape, evacuation, and rescue (EER) success probabilities. A set of realistic reliability targets for both catastrophic and local failures for representative safety and consequence categories associated with offshore installations was also presented. The reliability targets were expressed as maximum average annual failure probabilities. The method for converting these annual

  11. Exact reliability quantification of highly reliable systems with maintenance

    Bris, Radim, E-mail: radim.bris@vsb.c [VSB-Technical University Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Applied Mathematics, 17. listopadu 15, 70833 Ostrava-Poruba (Czech Republic)


    When a system is composed of highly reliable elements, exact reliability quantification may be problematic, because computer accuracy is limited. Inaccuracy can be due to different aspects. For example, an error may be made when subtracting two numbers that are very close to each other, or at the process of summation of many very different numbers, etc. The basic objective of this paper is to find a procedure, which eliminates errors made by PC when calculations close to an error limit are executed. Highly reliable system is represented by the use of directed acyclic graph which is composed from terminal nodes, i.e. highly reliable input elements, internal nodes representing subsystems and edges that bind all of these nodes. Three admissible unavailability models of terminal nodes are introduced, including both corrective and preventive maintenance. The algorithm for exact unavailability calculation of terminal nodes is based on merits of a high-performance language for technical computing MATLAB. System unavailability quantification procedure applied to a graph structure, which considers both independent and dependent (i.e. repeatedly occurring) terminal nodes is based on combinatorial principle. This principle requires summation of a lot of very different non-negative numbers, which may be a source of an inaccuracy. That is why another algorithm for exact summation of such numbers is designed in the paper. The summation procedure uses benefits from a special number system with the base represented by the value 2{sup 32}. Computational efficiency of the new computing methodology is compared with advanced simulation software. Various calculations on systems from references are performed to emphasize merits of the methodology.

  12. Long-Short Portfolio

    Leo Shubert


    Full Text Available Long-short strategies are one of the most successful tools, applied by hedge funds manager. One under-evaluated stock is bought (long position and an over-evaluated stock is sold (short position at the same time. After a short term, when the values of the stocks are as expected, profit can be realized by a closing transaction. The possibility to find first obvious over- and under-evaluated stocks depends on the number of participants in this markets. While the hedge funds strategies become more popular, the chance to achieve profit by this strategies is shrinking.Therefore two models to generate long-short portfolios are proposed. By this approaches a portfolio A for the long- and a portfolio B for the short position were computed. The difference of the values of A and B is designed to oscillate from negative to positive and reverse. This behavior of oscillating or mean reverting stock prices was stated by e.g. E. Fama and K. R. French (1988. Mean reversion of portfolios can offer the possibility of statistical arbitrage. The proposed linear models were tested by stocks of the Tokyo stock exchange. The results seem to be applicable and show an additional advantage of low systematic risk.

  13. Robust Reliability or reliable robustness? - Integrated consideration of robustness and reliability aspects

    Kemmler, S.; Eifler, Tobias; Bertsche, B.


    products are and vice versa. For a comprehensive understanding and to use existing synergies between both domains, this paper discusses the basic principles of Reliability- and Robust Design theory. The development of a comprehensive model will enable an integrated consideration of both domains...

  14. Idiopathic short stature.

    Pasquino, A M; Albanese, A; Bozzola, M; Butler, G E; Buzi, F; Cherubini, V; Chiarelli, F; Cavallo, L; Drop, S L; Stanhope, R; Kelnar, C J


    Idiopathic short stature (ISS) is a term used to describe the status of children with short stature that cannot be attributed to a specific cause. Many children diagnosed as having ISS have partial GH insensitivity, which can result from disturbances at various points of the GH-IGF-I axis. Several clinical studies on spontaneous growth in ISS showed that adult height was almost in the range of target height. GH treatment led to adult height not significantly higher than the pretreatment predicted adult height in most reports. No metabolic side effects have been observed, even when the dose was higher than in GH deficiency. Manipulation of puberty with gonadotrophin releasing hormone analogues reported by a few authors in a small number of children has shown conflicting results. Long-term psychological benefits of GH therapy for short normal children have not been demonstrated to date.

  15. 78 FR 30804 - Transmission Planning Reliability Standards


    ... proposed Reliability Standard TPL-001-2, submitted by the North American Electric Reliability Corporation... American Electric Reliability Corporation (NERC), the Commission-certified Electric Reliability... Microsoft Word format for viewing, printing, and/or downloading. To access this document in eLibrary,...


    Hakan SARIÇAM


    . Their ages ranged from 18 to 27, and the mean age of the participants was 21.3 years. Motivational Persistence Scale was used for concurrent validity. There is a significant correlation between the original and Turkish version of the scale in the equivalency was .89 (p= .00. KaiserMeyer-Olkin (KMO measure of sampling adequacy of .83 and a significant result on Bartlett’s test of sphericity χ2 = 503,877 (p<.001, df=24. Results of confirmatory factor analyses demonstrated that 8 items yielded two factors as original form and that the two-dimensional model was well fit (χ2 /df=2.06, p=.00011, RMSEA= .046, CFI=.95, GFI=.94, AGFI=.93, SRMR=.047. Factor loadings ranged from .42 to .77. In the concurrent validity significant relationships (r= .68 was found between the Motivational Persistence Scale and Shor Grit Scale. Cronbach alpha internal consistency coefficient was found as .83 for whole scale, .80 for sub-dimension of consistency of interest, .71 for sub-dimension of perseverance of effort. Test-retest reliability coefficient was .69 for whole scale. Corrected item-total correlations ranged from .33 to .65. As a result, it is possible to say that the Grit-S is a valid and reliable measurement tool to be used for the purpose of measuring grit, persevarance and persistence levels of individuals.

  17. Study on reliability technology of contactor relay

    LIU Guo-jin; ZHAO Jing-ying; WANG Hai-tao; YANG Chen-guang; SUN Shun-li


    In this paper, the reliability of contactor relay is studied. There are three main parts about reliability test and analysis. First, in order to analyze reliability level of contact relay, the failure ratio ranks are established as index base on the product level. Second, the reliability test method is put forward. The sample plan of reliability compliance test is gained from reliability sample theory. The failure criterion is ensured according to the failure modes of contactor relay. Third, after reliability test experiment, the analysis of failure physics is made and the failure reason is found.

  18. Defining Requirements for Improved Photovoltaic System Reliability

    Maish, A.B.


    Reliable systems are an essential ingredient of any technology progressing toward commercial maturity and large-scale deployment. This paper defines reliability as meeting system fictional requirements, and then develops a framework to understand and quantify photovoltaic system reliability based on initial and ongoing costs and system value. The core elements necessary to achieve reliable PV systems are reviewed. These include appropriate system design, satisfactory component reliability, and proper installation and servicing. Reliability status, key issues, and present needs in system reliability are summarized for four application sectors.

  19. Predicting Reliability of Tactical Network Using RBFNN

    WANG Xiao-kai; HOU Chao-zhen


    A description of the reliability evaluation of tactical network is given, which reflects not only the non-reliable factors of nodes and links but also the factors of network topological structure. On the basis of this description, a reliability prediction model and its algorithms are put forward based on the radial basis function neural network (RBFNN) for the tactical network. This model can carry out the non-linear mapping relationship between the network topological structure, the nodes reliabilities, the links reliabilities and the reliability of network. The results of simulation prove the effectiveness of this method in the reliability and the connectivity prediction for tactical network.

  20. Reliability of Wave Energy Converters

    Ambühl, Simon

    for welded structures at the Wavestar device includingdifferent control systems for harvesting energy from waves. In addition, a casestudy of different O&M strategies for WECs is discussed, and an example ofreliability-based structural optimization of the Wavestar foundation ispresented. The work performed......There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs tobecome successful and more competitive to other renewable electricity sources,the consideration of the structural reliability of WECs is essential.......Structural reliability considerations and optimizations impact operation andmaintenance (O&M) costs as well as the initial investment costs.Furthermore, there is a control system for WEC applications which defines theharvested energy but also the loads onto the structure. Therefore, extremeloads but also fatigue loads...

  1. Boolean networks with reliable dynamics

    Peixoto, Tiago P


    We investigated the properties of Boolean networks that follow a given reliable trajectory in state space. A reliable trajectory is defined as a sequence of states which is independent of the order in which the nodes are updated. We explored numerically the topology, the update functions, and the state space structure of these networks, which we constructed using a minimum number of links and the simplest update functions. We found that the clustering coefficient is larger than in random networks, and that the probability distribution of three-node motifs is similar to that found in gene regulation networks. Among the update functions, only a subset of all possible functions occur, and they can be classified according to their probability. More homogeneous functions occur more often, leading to a dominance of canalyzing functions. Finally, we studied the entire state space of the networks. We observed that with increasing systems size, fixed points become more dominant, moving the networks close to the frozen...

  2. "Reliability Of Fiber Optic Lans"

    Code n, Michael; Scholl, Frederick; Hatfield, W. Bryan


    Fiber optic Local Area Network Systems are being used to interconnect increasing numbers of nodes. These nodes may include office computer peripherals and terminals, PBX switches, process control equipment and sensors, automated machine tools and robots, and military telemetry and communications equipment. The extensive shared base of capital resources in each system requires that the fiber optic LAN meet stringent reliability and maintainability requirements. These requirements are met by proper system design and by suitable manufacturing and quality procedures at all levels of a vertically integrated manufacturing operation. We will describe the reliability and maintainability of Codenoll's passive star based systems. These include LAN systems compatible with Ethernet (IEEE 802.3) and MAP (IEEE 802.4), and software compatible with IBM Token Ring (IEEE 802.5). No single point of failure exists in this system architecture.

  3. Reliability of Wave Energy Converters

    Ambühl, Simon

    There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs to become successful and more competitive to other renewable electricity sources, the consideration of the structural reliability of WECs is essential....... Structural reliability considerations and optimizations impact operation and maintenance (O&M) costs as well as the initial investment costs. Furthermore, there is a control system for WEC applications which defines the harvested energy but also the loads onto the structure. Therefore, extreme loads but also...... of the Wavestar foundation is presented. The work performed in this thesis focuses on the Wavestar and WEPTOS WEC devices which are only two working principles out of a large diversity. Therefore, in order to gain general statements and give advice for standards for structural WEC designs, more working principles...

  4. Next Generation Reliable Transport Networks

    Zhang, Jiang

    of criticality and security, there are certain physical or logical segregation requirements between the avionic systems. Such segregations can be implemented on the proposed avionic networks with different hierarchies. In order to fulfill the segregation requirements, a tailored heuristic approach for solving......This thesis focuses the efforts on ensuring the reliability of transport networks and takes advantages and experiences from the transport networks into the networks for particular purposes. Firstly, the challenges of providing reliable multicast services on Multipath Label Switching......-Transport Profile (MPLS-TP) ring networks are addressed. Through the proposed protection structure and protection switching schemes, the recovery mechanism is enhanced in terms of recovery label consumption, operation simplicity and fine traffic engineering granularity. Furthermore, the extensions for existing...

  5. Gearbox Reliability Collaborative Bearing Calibration

    van Dam, J.


    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  6. Cost-effective solutions to maintaining smart grid reliability

    Qin, Qiu

    As the aging power systems are increasingly working closer to the capacity and thermal limits, maintaining an sufficient reliability has been of great concern to the government agency, utility companies and users. This dissertation focuses on improving the reliability of transmission and distribution systems. Based on the wide area measurements, multiple model algorithms are developed to diagnose transmission line three-phase short to ground faults in the presence of protection misoperations. The multiple model algorithms utilize the electric network dynamics to provide prompt and reliable diagnosis outcomes. Computational complexity of the diagnosis algorithm is reduced by using a two-step heuristic. The multiple model algorithm is incorporated into a hybrid simulation framework, which consist of both continuous state simulation and discrete event simulation, to study the operation of transmission systems. With hybrid simulation, line switching strategy for enhancing the tolerance to protection misoperations is studied based on the concept of security index, which involves the faulted mode probability and stability coverage. Local measurements are used to track the generator state and faulty mode probabilities are calculated in the multiple model algorithms. FACTS devices are considered as controllers for the transmission system. The placement of FACTS devices into power systems is investigated with a criterion of maintaining a prescribed level of control reconfigurability. Control reconfigurability measures the small signal combined controllability and observability of a power system with an additional requirement on fault tolerance. For the distribution systems, a hierarchical framework, including a high level recloser allocation scheme and a low level recloser placement scheme, is presented. The impacts of recloser placement on the reliability indices is analyzed. Evaluation of reliability indices in the placement process is carried out via discrete event

  7. Storage Reliability of Reserve Batteries


    batteries – Environmental concerns, lack of business – Non-availability of some critical materials • Lithium Oxyhalides are systems of choice – Good...exhibit good corrosion resistance to neutral electrolytes (LiAlCl4 in thionyl chloride and sulfuryl chloride ) • Using AlCl3 creates a much more corrosive...Storage Reliability of Reserve Batteries Jeff Swank and Allan Goldberg Army Research Laboratory Adelphi, MD 301-394-3116 ll l


    Gabriel BURLACU,


    Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator


    Adrian Stere PARIS


    Full Text Available The mechanical reliability uses many statistical tools to find the factors of influence and their levels inthe optimization of parameters on the basis of experimental data. Design of Experiments (DOE techniquesenables designers to determine simultaneously the individual and interactive effects of many factors that couldaffect the output results in any design. The state-of-the-art in the domain implies extended use of software and abasic mathematical knowledge, mainly applying ANOVA and the regression analysis of experimental data.

  10. Improved reliability of power modules

    Baker, Nick; Liserre, Marco; Dupont, Laurent


    Power electronic systems play an increasingly important role in providing high-efficiency power conversion for adjustable-speed drives, power-quality correction, renewable-energy systems, energy-storage systems, and electric vehicles. However, they are often presented with demanding operating env...... temperature cycling conditions on the system. On the other hand, safety requirements in the aerospace and automotive industries place rigorous demands on reliability....

  11. Reliability Analysis of Sensor Networks

    JIN Yan; YANG Xiao-zong; WANG Ling


    To Integrate the capacity of sensing, communication, computing, and actuating, one of the compelling technological advances of these years has been the appearance of distributed wireless sensor network (DSN) for information gathering tasks. In order to save the energy, multi-hop routing between the sensor nodes and the sink node is necessary because of limited resource. In addition, the unpredictable conditional factors make the sensor nodes unreliable. In this paper, the reliability of routing designed for sensor network and some dependability issues of DSN, such as MTTF(mean time to failure) and the probability of connectivity between the sensor nodes and the sink node are analyzed.Unfortunately, we could not obtain the accurate result for the arbitrary network topology, which is # P-hard problem.And the reliability analysis of restricted topologies clustering-based is given. The method proposed in this paper will show us a constructive idea about how to place energyconstrained sensor nodes in the network efficiently from the prospective of reliability.

  12. Reliability in individual monitoring service.

    Mod Ali, N


    As a laboratory certified to ISO 9001:2008 and accredited to ISO/IEC 17025, the Secondary Standard Dosimetry Laboratory (SSDL)-Nuclear Malaysia has incorporated an overall comprehensive system for technical and quality management in promoting a reliable individual monitoring service (IMS). Faster identification and resolution of issues regarding dosemeter preparation and issuing of reports, personnel enhancement, improved customer satisfaction and overall efficiency of laboratory activities are all results of the implementation of an effective quality system. Review of these measures and responses to observed trends provide continuous improvement of the system. By having these mechanisms, reliability of the IMS can be assured in the promotion of safe behaviour at all levels of the workforce utilising ionising radiation facilities. Upgradation of in the reporting program through a web-based e-SSDL marks a major improvement in Nuclear Malaysia's IMS reliability on the whole. The system is a vital step in providing a user friendly and effective occupational exposure evaluation program in the country. It provides a higher level of confidence in the results generated for occupational dose monitoring of the IMS, thus, enhances the status of the radiation protection framework of the country.

  13. Reliability engineering theory and practice

    Birolini, Alessandro


    This book shows how to build in and assess reliability, availability, maintainability, and safety (RAMS) of components, equipment, and systems. It presents the state of the art of reliability (RAMS) engineering, in theory & practice, and is based on over 30 years author's experience in this field, half in industry and half as Professor of Reliability Engineering at the ETH, Zurich. The book structure allows rapid access to practical results. Methods & tools are given in a way that they can be tailored to cover different RAMS requirement levels. Thanks to Appendices A6 - A8 the book is mathematically self-contained, and can be used as a textbook or as a desktop reference with a large number of tables (60), figures (210), and examples / exercises^ 10,000 per year since 2013) were the motivation for this final edition, the 13th since 1985, including German editions. Extended and carefully reviewed to improve accuracy, it represents the continuous improvement effort to satisfy reader's needs and confidenc...

  14. Temporal reliability and lateralization of the resting-state language network.

    Linlin Zhu

    Full Text Available The neural processing loop of language is complex but highly associated with Broca's and Wernicke's areas. The left dominance of these two areas was the earliest observation of brain asymmetry. It was demonstrated that the language network and its functional asymmetry during resting state were reproducible across institutions. However, the temporal reliability of resting-state language network and its functional asymmetry are still short of knowledge. In this study, we established a seed-based resting-state functional connectivity analysis of language network with seed regions located at Broca's and Wernicke's areas, and investigated temporal reliability of language network and its functional asymmetry. The language network was found to be temporally reliable in both short- and long-term. In the aspect of functional asymmetry, the Broca's area was found to be left lateralized, while the Wernicke's area is mainly right lateralized. Functional asymmetry of these two areas revealed high short- and long-term reliability as well. In addition, the impact of global signal regression (GSR on reliability of the resting-state language network was investigated, and our results demonstrated that GSR had negligible effect on the temporal reliability of the resting-state language network. Our study provided methodology basis for future cross-culture and clinical researches of resting-state language network and suggested priority of adopting seed-based functional connectivity for its high reliability.

  15. A short-form measure of loneliness.

    Hays, R D; DiMatteo, M R


    The revised UCLA Loneliness Scale (ULS-20) and a four-item short form (ULS-4) are widely used in personality research (Russell, Peplau, & Cutrona, 1980). In an exploratory factor analysis of the ULS-20, we identified eight items that loaded substantially on the first factor. These items were combined to form an alternative short-form measure, the ULS-8. The results of this study indicate that the ULS-8 is reliable, valid, and a better substitute for the ULS-20 than is the ULS-4. Consistent with the previous research, the loneliness measures (ULS-20, ULS-8, ULS-4) were strongly related to socially undesirable personality characteristics, but loneliness was uncorrelated with the six different health-related behaviors (exercise, meal regularity, alcohol use, hard drug use, smoking, and hours of sleep) assessed in this study.


    Z Moinfar


    Full Text Available Short rib polydactyly syndrome (SRPS is a very rare congenital anomaly that is classified into four subtypes. It is an autosomal recessive inherited disease. We report a case of this syndrome without a previous family history of congenital defects.

  17. Short-rotation plantations

    Philip E. Pope; Jeffery O. Dawson


    Short-rotation plantations offer several advantages over longer, more traditional rotations. They enhance the natural productivity of better sites and of tree species with rapid juvenile growth. Returns on investment are realized in a shorter period and the risk of loss is reduced compared with long term investments. Production of wood and fiber can be maximized by...

  18. Congenital Short QT Syndrome

    Charles Antzelevitch


    Full Text Available Long QT intervals in the ECG have long been associated with sudden cardiac death. The congenital long QT syndrome was first described in individuals with structurally normal hearts in 1957.1 Little was known about the significance of a short QT interval. In 1993, after analyzing 6693 consecutive Holter recordings Algra et al concluded that an increased risk of sudden death was present not only in patients with long QT interval, but also in patients with short QT interval (<400 ms.2 Because this was a retrospective analysis, further evaluation of the data was not possible. It was not until 2000 that a short-QT syndrome (SQTS was proposed as a new inherited clinical syndrome by Gussak et al.3 The initial report was of two siblings and their mother all of whom displayed persistently short QT interval. The youngest was a 17 year old female presenting with several episodes of paroxysmal atrial fibrillation requiring electrical cardioversion.3 Her QT interval measured 280 msec at a heart rate of 69. Her 21 year old brother displayed a QT interval of 272 msec at a heart rate of 58, whereas the 51 year old mother showed a QT of 260 msec at a heart rate of 74. The authors also noted similar ECG findings in another unrelated 37 year old patient associated with sudden cardiac death.

  19. Rasch Analysis of the Geriatric Depression Scale--Short Form

    Chiang, Karl S.; Green, Kathy E.; Cox, Enid O.


    Purpose: The purpose of this study was to examine scale dimensionality, reliability, invariance, targeting, continuity, cutoff scores, and diagnostic use of the Geriatric Depression Scale-Short Form (GDS-SF) over time with a sample of 177 English-speaking U.S. elders. Design and Methods: An item response theory, Rasch analysis, was conducted with…

  20. Rasch Analysis of the Geriatric Depression Scale--Short Form

    Chiang, Karl S.; Green, Kathy E.; Cox, Enid O.


    Purpose: The purpose of this study was to examine scale dimensionality, reliability, invariance, targeting, continuity, cutoff scores, and diagnostic use of the Geriatric Depression Scale-Short Form (GDS-SF) over time with a sample of 177 English-speaking U.S. elders. Design and Methods: An item response theory, Rasch analysis, was conducted with…

  1. Reliability and Security - Convergence or Divergence



    Full Text Available Reliability, as every technical field, must adapt to the new demands imposed by reality. Started initially as a field designed to control and ensure the smooth functionality of an element or technical system, reliability has reached the stage where the discussion is about the reliability management, similar to the other top-level fields. Security has its own contribution to the reliability of a system; a reliable system is a system with reliable security. In order for a system to be reliable, that means clear and safe, all its components must be reliable. In the following pages we will talk about the two main facts - reliability and security - to determine both the convergence and the divergence points.

  2. Advanced Functionalities for Highly Reliable Optical Networks

    An, Yi

    This thesis covers two research topics concerning optical solutions for networks e.g. avionic systems. One is to identify the applications for silicon photonic devices for cost-effective solutions in short-range optical networks. The other one is to realise advanced functionalities in order to in......) using two exclusive OR (XOR) gates realised by four-wave mixing (FWM) in semiconductor optical amplifiers (SOAs) is experimentally demonstrated and very low (~ 1 dB) total operation penalty is achieved....... to increase the availability of highly reliable optical networks. A cost-effective transmitter based on a directly modulated laser (DML) using a silicon micro-ring resonator (MRR) to enhance its modulation speed is proposed, analysed and experimentally demonstrated. A modulation speed enhancement from 10 Gbit...... interconnects and network-on-chips. A novel concept of all-optical protection switching scheme is proposed, where fault detection and protection trigger are all implemented in the optical domain. This scheme can provide ultra-fast establishment of the protection path resulting in a minimum loss of data...

  3. Structural reliability analysis and reliability-based design optimization: Recent advances

    Qiu, ZhiPing; Huang, Ren; Wang, XiaoJun; Qi, WuChao


    We review recent research activities on structural reliability analysis, reliability-based design optimization (RBDO) and applications in complex engineering structural design. Several novel uncertainty propagation methods and reliability models, which are the basis of the reliability assessment, are given. In addition, recent developments on reliability evaluation and sensitivity analysis are highlighted as well as implementation strategies for RBDO.

  4. Decision theory in structural reliability

    Thomas, J. M.; Hanagud, S.; Hawk, J. D.


    Some fundamentals of reliability analysis as applicable to aerospace structures are reviewed, and the concept of a test option is introduced. A decision methodology, based on statistical decision theory, is developed for determining the most cost-effective design factor and method of testing for a given structural assembly. The method is applied to several Saturn V and Space Shuttle structural assemblies as examples. It is observed that the cost and weight features of the design have a significant effect on the optimum decision.

  5. Reliability of steam generator tubing

    Kadokami, E. [Mitsubishi Heavy Industries Ltd., Hyogo-ku (Japan)


    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  6. Designing for Reliability and Robustness

    Svetlik, Randall G.; Moore, Cherice; Williams, Antony


    Long duration spaceflight has a negative effect on the human body, and exercise countermeasures are used on-board the International Space Station (ISS) to minimize bone and muscle loss, combatting these effects. Given the importance of these hardware systems to the health of the crew, this equipment must continue to be readily available. Designing spaceflight exercise hardware to meet high reliability and availability standards has proven to be challenging throughout the time the crewmembers have been living on ISS beginning in 2000. Furthermore, restoring operational capability after a failure is clearly time-critical, but can be problematic given the challenges of troubleshooting the problem from 220 miles away. Several best-practices have been leveraged in seeking to maximize availability of these exercise systems, including designing for robustness, implementing diagnostic instrumentation, relying on user feedback, and providing ample maintenance and sparing. These factors have enhanced the reliability of hardware systems, and therefore have contributed to keeping the crewmembers healthy upon return to Earth. This paper will review the failure history for three spaceflight exercise countermeasure systems identifying lessons learned that can help improve future systems. Specifically, the Treadmill with Vibration Isolation and Stabilization System (TVIS), Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), and the Advanced Resistive Exercise Device (ARED) will be reviewed, analyzed, and conclusions identified so as to provide guidance for improving future exercise hardware designs. These lessons learned, paired with thorough testing, offer a path towards reduced system down-time.

  7. Toward Real-time Multi-criteria Decision Making for Bus Service Reliability Optimisation

    Tran, Vu The; Eklund, Peter; Cook, Chris


    factors (such as traffic congestion and bad weather) in high frequency transit operations often cause irregular headway that can result in decreased service reliability. The approach proposed in this paper, which has the capability of handling the uncertainty of transit operations based on Multi......-objective evolutionary algorithm using a dynamic Bayesian network, applies preventive strategies to forestall bus unreliability and, where unreliability is evident, restore reliability using corrective strategies. 'Holding', 'expressing', 'short-turning' and 'deadheading' are the corrective strategies considered...

  8. 76 FR 66057 - North American Electric Reliability Corporation; Order Approving Regional Reliability Standard


    ... Reliability Standard PRC-002-NPCC- 01, and NPCC's guidance establishes maintenance and testing expectations... Energy Regulatory Commission 61,043] North American Electric Reliability Corporation; Order Approving Regional Reliability Standard Issued October 20, 2011. Before Commissioners: Jon Wellinghoff, Chairman...

  9. 76 FR 16240 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits


    ... Reliability Operating Limits AGENCY: Federal Energy Regulatory Commission, DOE. ACTION: Final rule. SUMMARY... instances of exceeding Interconnection Reliability. Operating Limits. The Commission also approves the... system operating limits other than interconnection reliability operating limits. DATES: Effective...

  10. 76 FR 23222 - Electric Reliability Organization Interpretation of Transmission Operations Reliability


    ... Energy Regulatory Commission 18 CFR Part 40 Electric Reliability Organization Interpretation of Transmission Operations Reliability AGENCY: Federal Energy Regulatory Commission. ACTION: Notice of Proposed... Commission (Commission) proposes to approve the North American Electric Reliability Corporation's...

  11. 76 FR 23171 - Electric Reliability Organization Interpretations of Interconnection Reliability Operations and...


    ... the system remains functional, the information can be compelled by the Reliability Coordinator. \\32... reliability coordinator and neighboring systems upon request, or when the loss of the communication channel... (Technical Information), Office of Electric Reliability, Federal Energy Regulatory Commission, 888...

  12. Cacades: A reliable dissemination protocol for data collection sensor network

    Peng, Y.; Song, W.; Huang, R.; Xu, M.; Shirazi, B.; LaHusen, R.; Pei, G.


    In this paper, we propose a fast and reliable data dissemination protocol Cascades to disseminate data from the sink(base station) to all or a subset of nodes in a data collection sensor network. Cascades makes use of the parentmonitor-children analogy to ensure reliable dissemination. Each node monitors whether or not its children have received the broadcast messages through snooping children's rebroadcasts or waiting for explicit ACKs. If a node detects a gap in its message sequences, it can fetch the missing messages from its neighbours reactively. Cascades also considers many practical issues for field deployment, such as dynamic topology, link/node failure, etc.. It therefore guarantees that a disseminated message from the sink will reach all intended receivers and the dissemination is terminated in a short time period. Notice that, all existing dissemination protocols either do not guarantee reliability or do not terminate [1, 2], which does not meet the requirement of real-time command control. We conducted experiment evaluations in both TOSSIM simulator and a sensor network testbed to compare Cascades with those existing dissemination protocols in TinyOS sensor networks, which show that Cascades achieves a higher degree of reliability, lower communication cost, and less delivery delay. ??2009 IEEE.

  13. The Eysenck Personality Questionnaire Brief Version: factor structure and reliability.

    Sato, Toru


    The short scale of the Eysenck Personality Questionnaire-Revised (EPQR-S; H. J. Eysenck & S. B. G. Eysenck, 1992) is a 48-item personality questionnaire primarily designed to measure an individual's level of extraversion (vs. introversion) and neuroticism. Although L. J. Francis, L. B. Brown, and R. Philipchalk (1992) created the Eysenck Personality Questionnaire Revised-Abbreviated (EPQR-A), an even briefer version of the EPQR-S, the reliability coefficients of some of the measures have been less than satisfactory (S. Forrest, C. A. Lewis, & M. Shevlin, 2000). Because brevity and reliability are both extremely important, the author of the present study created a briefer version of the EPQR-S, more reliable than the EPQR-A, by making slight alterations in the item content as well as the response format of the EPQR-S. Two hundred and sixty eight participants completed the original EPQR-S and the 24-item newly revised briefer version of the EPQR-S (EPQ-BV) twice. The findings revealed that the EPQ-BV has good internal consistency, test-retest reliability, and concurrent validity. A principal component analysis revealed a solution with factor loadings that accurately reflected the primary measures of the EPQR-S. These findings are discussed in relation to the psychometric properties of the EPQR-A and the original version of the EPQR-S.

  14. Reliability-Based Calibration of Load Duration Factors for Timber Structures

    Sørensen, John Dalsgaard; Svensson, Staffan; Stang, Birgitte Friis Dela


    states and stochastic models for timber structures, load duration factors are calibrated using probabilistic methods. Load duration e.ects are estimated on basis of simulation of realizations of wind, snow and imposed loads in accordance with the load models in the Danish structural codes. Three damage...... is evaluated using representative short- and long-term limit states, and the load duration factor k mod is estimated using the probabilistic model such that equivalent reliability levels are obtained using short- and long-term design equations. Time variant reliability aspect is considered using a simple...

  15. Reliability-Based Optimization in Structural Engineering

    Enevoldsen, I.; Sørensen, John Dalsgaard


    -based optimal inspection planning and reliability-based experiment planning. It is explained how these optimization problems can be solved by application of similar techniques. The reliability estimation is limited to first order reliability methods (FORM) for both component and systems reliability evaluation......, inclusion of the finite element method as the response evaluation tool and how the size of the problem can be made practicable. Finally, the important task of model evaluation and sensitivity analysis of the optimal solution is treated including a strategy for model-making with both pre and post-analysis.......In this paper reliability-based optimization problems in structural engineering are formulated on the basis of the classical decision theory. Several formulations are presented: Reliability-based optimal design of structural systems with component or systems reliability constraints, reliability...

  16. Multi-Agent System for Resource Reliability


    1 research and development of a prototype for network resource reliability has laid the groundwork for the Phase 2 implementation of MASRR, a Multi - Agent System for Resource Reliability, and its eventual commercialization.

  17. Software Architecture Reliability Analysis using Failure Scenarios

    Tekinerdogan, B.; Sözer, Hasan; Aksit, Mehmet

    With the increasing size and complexity of software in embedded systems, software has now become a primary threat for the reliability. Several mature conventional reliability engineering techniques exist in literature but traditionally these have primarily addressed failures in hardware components


    Zhou Lianke; Cui Gang; Luo Danyan; Liu Hongwei


    In this paper,a reliability enhanced and density adaptive data disseminating scheme is proposed for Vehicular Ad hoc NETworks (VANETs).The distributed on demand inquiring and responding mechanism is employed to get nodes' connectivity information.The announcing-listening process is also designed to find the nodes with bigger additional degree to rebroadcast,by which the relaying node is selected freely from density's influence.Simultaneously,a reliability parameter is designed to choose redundant relays for each hop.According to the importance of the broadcast,the parameter is set by the source node properly.Simulation results show that the scheme has achieved good performances such as low forwarding ratio,short latency and low load.The broadcast coverage ratio is ensured against the influence of key link errors and relaying nodes failure by paying suitable additional communication.

  19. Reliability and validity in medical research


    Scientists commonly refer to study instruments duringmedical research. In fact, the reliability and validity issuesgo beyond psychometric studies and can be linked withany kind measurements. In this study we aimed to explainthe reliability and validity concepts by giving examples.It is possible to evaluate the reliability and validity of aninstrument by scientific methods. If we speak of reliability,we have to mention stability (having the same results inrepeated measurements from the same sa...

  20. Nonelectronic Parts Reliability Data - 2


    33 DRIFT 27 OPEN Z3 UNSTABLE 17 BATTERIES Lithium - Sulfer Dioxide INTERNAL SHORT z1 INTERNAL OPEN 7 LARGE STARTUP DELAY 50 LOW ENERGY CAPACITY 2...215 SECTION 4: FAILURE MODES AND MECHANISMS Z29 Operational Failure Modes and Mechanisms Z31 Batteries 231 Lead-Acid Z31 Nickel-Cadmium 232 Bearings...Explosive Z3 General 24 Hydraulic Z4 Linear Z5 Rotary Z5 Battery Z6 Lead Acid 26 Mercury Z6 Nickel Cadmium Z6 Non-Rechargeable 7 Rechargeable 27 Bearing

  1. Short Text Classification: A Survey

    Ge Song


    Full Text Available With the recent explosive growth of e-commerce and online communication, a new genre of text, short text, has been extensively applied in many areas. So many researches focus on short text mining. It is a challenge to classify the short text owing to its natural characters, such as sparseness, large-scale, immediacy, non-standardization. It is difficult for traditional methods to deal with short text classification mainly because too limited words in short text cannot represent the feature space and the relationship between words and documents. Several researches and reviews on text classification are shown in recent times. However, only a few of researches focus on short text classification. This paper discusses the characters of short text and the difficulty of short text classification. Then we introduce the existing popular works on short text classifiers and models, including short text classification using sematic analysis, semi-supervised short text classification, ensemble short text classification, and real-time classification. The evaluations of short text classification are analyzed in our paper. Finally we summarize the existing classification technology and prospect for development trend of short text classification

  2. MMPI-2 short form proposal: CAUTION.

    Gass, Carlton S; Gonzalez, Camille


    The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is widely used in neuropsychology, though its length (567 items) is sometimes prohibitive. This study investigated some psychometric characteristics of the 180-item version of the MMPI-2 () in order to delineate its strengths, limitations, and appropriate scope of clinical application. Limited reliability and poor predictive accuracy were recently reported for many of the MMPI-2 short-form scales in a study that used 205 brain-injured patients. In the present investigation, we used a psychiatric sample (N=186) with normal neurological findings to examine short-form accuracy in predicting basic scale scores, profile code types, identifying high-point scales, and classifying scores as pathological (T>/=65) or normal-range. The results suggest that, even as applied to neurologically normal individuals, the proposed short form of the MMPI-2 is unreliable for predicting clinical code types, identifying the high-point scale, or predicting the scores on most of the basic scales. In contrast, this short form can be used to predict whether the full-scale scores fall within the pathological range (T>/=65). These findings suggest that clinicians might be able to salvage a small amount of information from the shortened (180-item) version of the MMPI-2 when MMPI-2 protocols are incomplete. However, clinicians should not use a standard interpretive approach with this test, and routine clinical application is unwarranted. Future evaluations of short-form validity should provide a more detailed examination of individual protocols, including an analysis of the frequency of accurate prediction of full-form scores.

  3. Short QT syndrome

    Fiorenzo Gaita


    Full Text Available The short QT syndrome (SQTS is a recently described genetic arrhythmogenic disorder, characterized by abnormally short QT intervals on surface electrocardiogram (ECG and a high incidence of sudden death (SD during life, including the first months of life. The inheritance of SQTS is autosomal dominant, with genetic heterogeneity. Gain-of-function mutations in 3 genes encoding potassium channels have been associated to the disease: KCNH2 encoding IKr (SQT1, KCNQ1 encoding IKs (SQT2, and KCNJ2 encoding IK1 (SQT3. Loss-of-function mutations in 3 genes encoding the cardiac L-type calcium channel, CACNA1C, CACNB2b and CACNA2D1 may underlie a mixed phenotype of Brugada pattern ECG (or non-specific repolarization changes in case of CACNA2D1 and shorter than normal QT intervals. Clinical presentation is often severe, as cardiac arrest represents the first clinical presentation in most subjects. Moreover, often a noticeable family history of cardiac SD is present. Atrial fibrillation may be observed, also in young individuals. At electrophysiological study, short atrial and ventricular refractory periods are found, and atrial and ventricular fibrillation are easily induced by programmed electrical stimulation. The outcome of patients with SQTS becomes relatively safe when they are identified and treated. Currently, the suggested therapeutic strategy is an implantable cardioverter- defibrillator (ICD in patients with personal history of aborted SD or syncope. In asymptomatic adult patients from highly symptomatic families and in newborn children pharmacological treatment with hydroquinidine, which has been shown to prolong the QT interval and reduce the inducibility of ventricular arrhythmias, may be proposed.

  4. Monitoring Travel Time Reliability on Freeways

    Tu, Huizhao


    Travel time and travel time reliability are important attributes of a trip. The current measures of reliability have in common that in general they all relate to the variability of travel times. However, travel time reliability does not only rely on variability but also on the stability of travel

  5. The Highest & Lowest Reliability Achievable with Redundancy

    Becker, Peter W.


    -dependent, it is difficult to assess the reliability of the system. The paper describes the ¿-transformation by which the highest and lowest reliability achievable can be determined for a configuration using components with specified reliabilities. As a by-product we become able to pinpoint the statistical relationships...

  6. 46 CFR 169.619 - Reliability.


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Reliability. 169.619 Section 169.619 Shipping COAST... Electrical Steering Systems § 169.619 Reliability. (a) Except where the OCMI judges it impracticable, the... be below that necessary for the safe navigation of the vessel. (c) The strength and reliability...

  7. Reliability and heterogeneity of railway services

    M.J.C.M. Vromans (Michiel); R. Dekker (Rommert); L.G. Kroon (Leo)


    textabstractReliability is one of the key factors in transportation, both for passengers and for cargo. This paper examines reliability in public railway systems. Reliability of railway services is a complex matter, since there are many causes for disruptions and at least as many causes for delays t

  8. Making statistical inferences about software reliability

    Miller, Douglas R.


    Failure times of software undergoing random debugging can be modelled as order statistics of independent but nonidentically distributed exponential random variables. Using this model inferences can be made about current reliability and, if debugging continues, future reliability. This model also shows the difficulty inherent in statistical verification of very highly reliable software such as that used by digital avionics in commercial aircraft.

  9. Monitoring Travel Time Reliability on Freeways

    Tu, Huizhao


    Travel time and travel time reliability are important attributes of a trip. The current measures of reliability have in common that in general they all relate to the variability of travel times. However, travel time reliability does not only rely on variability but also on the stability of travel ti

  10. 2016 NREL Photovoltaic Module Reliability Workshop

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)


    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology - both critical goals for moving PV technologies deeper into the electricity marketplace.

  11. 2015 NREL Photovoltaic Module Reliability Workshops

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)


    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  12. 75 FR 71625 - System Restoration Reliability Standards


    ... Energy Regulatory Commission 18 CFR Part 40 System Restoration Reliability Standards November 18, 2010... to approve Reliability Standards EOP-001-1 (Emergency Operations Planning), EOP- 005-2 (System... modifications to proposed EOP-005-2 and EOP-006-2. The proposed Reliability Standards require that...

  13. Reliability of Hydrox explosive blasting

    Chikunov, V.I.; Chulkov, O.G.; Domanov, V.P.


    The safest method of blasting in coal mines with methane and coal dust hazards is with the flameless Hydrox charges. The results of operational tests on Hydrox BV-A2U charges with a I-43 initiator in underground coal mines are discussed. Efficiency and reliability of blasting using Hydrox BV-A2U compared to BV-48 Hydrox charges is evaluated. Results of blasting and the percentage of charge failures are given in tables. It is suggested that BV-A2U Hydrox charges are superior to BV-48, as no charge failures occur, operational time of BV-A2U is up to 5 seconds and the maximum operational time spread is 1.8 sec (weight of initiator 0.05 kg). Blasting properties of BV-A2U are stable and do not change as a result of long storage. (In Russian)

  14. System Reliability of Timber Structures

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard


    For reduction of the risk of collapse in the event of loss of structural element(s), a structural engineer may take necessary steps to design a collapse-resistant structure that is insensitive to accidental circumstances e.g. by incorporating characteristics like redundancy, ties, ductility, key ...... elements, alternate load path(s) etc. in the structural design. In general these characteristics can have a positive influence on system reliability of a structure however, in Eurocodes ductility is only awarded for concrete and steel structures but not for timber structures. It is well......-know that structural systems can redistribute internal forces due to ductility of a connection, i.e. some additional loads can be carried by the structure. The same effect is also possible for reinforced concrete structures and structures of steel. However, for timber structures codes do not award that ductility...

  15. Reliability on ISS Talk Outline

    Misiora, Mike


    1. Overview of ISS 2. Space Environment and it effects a. Radiation b. Microgravity 3. How we ensure reliability a. Requirements b. Component Selection i. Note: I plan to stay away from talk about Rad Hardened components and talk about why we use older processors because they are less susceptible to SEUs. c. Testing d. Redundancy / Failure Tolerance e. Sparing strategies 4. Operational Examples a. Multiple MDM Failures on 6A due to hard drive failure In general, my plan is to only talk about data that is currently available via normal internet sources to ensure that I stay away from any topics that would be Export Controlled, ITAR, or NDA-controlled. The operational example has been well-reported on in the media and those are the details that I plan to cover. Additionally I am not planning on using any slides or showing any photos during the talk.

  16. The reliability of an education-related self-efficacy scale for people with psychiatric disabilities.

    Harris, Meredith; Gladman, Beverley; Hennessy, Nicole; Lloyd, Chris; Mowry, Bryan; Waghorn, Geoffrey


    We investigated the reliability of the Education-related Self Efficacy Scale (ESS-40), a measure of self-efficacy at a core task level designed for people with psychiatric disabilities. Sixty community residents with schizophrenia or schizoaffective disorder participated. The ESS-40 was administered twice via telephone interview. Short cycle test-retest reliability was very good for the total score and most items. The measure demonstrated signs of a coherent internal structure, adequate face validity, good client acceptability, and promising utility. The reliability evidence supports its use in community mental health services and in psychiatric rehabilitation settings. Sensitivity and predictive validity require further investigation.

  17. Scottish Short Stone Rows

    Ruggles, Clive L. N.

    Short stone rows received a good deal of attention during the 1980s and 1990s, at a time when archaeoastronomy in prehistoric Britain and Ireland was moving beyond reassessments of Alexander Thom's "megalithic observatories" by identifying coherent groups of similar monuments with clear orientation trends. Many such rows are found in western Scotland, with the main concentration in Argyll and the island of Mull. Systematic analyses of their orientations produced credible evidence of an awareness of the 18.6-year lunar node cycle, within a "primary-secondary" pattern whereby isolated rows were oriented close to moonrise or moonset at the southern major standstill limit, while others oriented in this way were accompanied by a second row oriented in a declination range that could be interpreted either as lunar or solar. A detailed investigation of the landscape situation of the sites in northern Mull, accompanied by excavations at two of the sites, suggested that they were deliberately placed in locations where critical moonsets would be seen against prominent distant landscape features, but where the distant horizon in most or all other directions was hidden from view. A lack of independent archaeological evidence may help to explain why archaeoastronomical investigations at short stone rows have never progressed beyond "data-driven" studies of orientations and landscape situation. Nonetheless, the work that was done at these sites raised important general methodological issues, and pioneered techniques, that remain relevant across archaeoastronomy today.

  18. Short bowel syndrome.

    Donohoe, Claire L


    The short bowel syndrome (SBS) is a state of malabsorption following intestinal resection where there is less than 200 cm of intestinal length. The management of short bowel syndrome can be challenging and is best managed by a specialised multidisciplinary team. A good understanding of the pathophysiological consequences of resection of different portions of the small intestine is necessary to anticipate and prevent, where possible, consequences of SBS. Nutrient absorption and fluid and electrolyte management in the initial stages are critical to stabilisation of the patient and to facilitate the process of adaptation. Pharmacological adjuncts to promote adaptation are in the early stages of development. Primary restoration of bowel continuity, if possible, is the principle mode of surgical treatment. Surgical procedures to increase the surface area of the small intestine or improve its function may be of benefit in experienced hands, particularly in the paediatric population. Intestinal transplant is indicated at present for patients who have failed to tolerate long-term parenteral nutrition but with increasing experience, there may be a potentially expanded role for its use in the future.

  19. The short toric polynomial

    Hetyei, Gábor


    We introduce the short toric polynomial associated to a graded Eulerian poset. This polynomial contains the same information as the two toric polynomials introduced by Stanley, but allows different algebraic manipulations. The intertwined recurrence defining Stanley's toric polynomials may be replaced by a single recurrence, in which the degree of the discarded terms is independent of the rank. A short toric variant of the formula by Bayer and Ehrenborg, expressing the toric $h$-vector in terms of the $cd$-index, may be stated in a rank-independent form, and it may be shown using weighted lattice path enumeration and the reflection principle. We use our techniques to derive a formula expressing the toric $h$-vector of a dual simplicial Eulerian poset in terms of its $f$-vector. This formula implies Gessel's formula for the toric $h$-vector of a cube, and may be used to prove that the nonnegativity of the toric $h$-vector of a simple polytope is a consequence of the Generalized Lower Bound Theorem holding for ...

  20. A single-item measure of social identification: reliability, validity, and utility.

    Postmes, Tom; Haslam, S Alexander; Jans, Lise


    This paper introduces a single-item social identification measure (SISI) that involves rating one's agreement with the statement 'I identify with my group (or category)' followed by a 7-point scale. Three studies provide evidence of the validity (convergent, divergent, and test-retest) of SISI with a broad range of social groups. Overall, the estimated reliability of SISI is good. To address the broader issue of single-item measure reliability, a meta-analysis of 16 widely used single-item measures is reported. The reliability of single-item scales ranges from low to reasonably high. Compared with this field, reliability of the SISI is high. In general, short measures struggle to achieve acceptable reliability because the constructs they assess are broad and heterogeneous. In the case of social identification, however, the construct appears to be sufficiently homogeneous to be adequately operationalized with a single item.

  1. Exploration of Complexity in Software Reliability

    CHU Yanming; XU Shiyi


    Traditionally, timing and the failure rate are the only two factors considered in software reliability formula, which is actually incomplete. Reliability should be redefined as a function of software complexity, test effectiveness, and operating environment. This paper focuses on software complexity with its relation to the software reliability. Today, many software complexity measurements have been proposed, but most of them treat the reliability model incompletely. This paper proposes a new method which considers a relatively complete view of software reliability including its complexity and test effectiveness of the software being tested.

  2. On reliability optimization for power generation systems


    The reliability level of a power generation system is an important problem which is concerned by both electricity producers and electricity consumers. Why? It is known that the high reliability level may result in additional utility cost, and the low reliability level may result in additional consumer's cost, so the optimum reliability level should be determined such that the total cost can reach its minimum. Four optimization models for power generation system reliability are constructed, and the proven efficient solutions for these models are also given.

  3. Reliability of Power Electronic Converter Systems

    -link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault......-tolerant adjustable speed drive systems; mission profile oriented reliability design in wind turbine and photovoltaic systems; reliability of power conversion systems in photovoltaic applications; power supplies for computers; and high-power converters. Reliability of Power Electronic Converter Systems is essential...... reading for researchers, professionals and students working with power electronics and their applications, particularly those specializing in the development and application of power electronic converters and systems....

  4. Short term depression unmasks the ghost frequency.

    Tjeerd V Olde Scheper

    Full Text Available Short Term Plasticity (STP has been shown to exist extensively in synapses throughout the brain. Its function is more or less clear in the sense that it alters the probability of synaptic transmission at short time scales. However, it is still unclear what effect STP has on the dynamics of neural networks. We show, using a novel dynamic STP model, that Short Term Depression (STD can affect the phase of frequency coded input such that small networks can perform temporal signal summation and determination with high accuracy. We show that this property of STD can readily solve the problem of the ghost frequency, the perceived pitch of a harmonic complex in absence of the base frequency. Additionally, we demonstrate that this property can explain dynamics in larger networks. By means of two models, one of chopper neurons in the Ventral Cochlear Nucleus and one of a cortical microcircuit with inhibitory Martinotti neurons, it is shown that the dynamics in these microcircuits can reliably be reproduced using STP. Our model of STP gives important insights into the potential roles of STP in self-regulation of cortical activity and long-range afferent input in neuronal microcircuits.

  5. Reliability of the NINDS Myotatic Reflex Scale.

    Litvan, I; Mangone, C A; Werden, W; Bueri, J A; Estol, C J; Garcea, D O; Rey, R C; Sica, R E; Hallett, M; Bartko, J J


    The assessment of deep tendon reflexes is useful for localization and diagnosis of neurologic disorders, but only a few studies have evaluated their reliability. We assessed the reliability of four neurologists, instructed in two different countries, in using the National Institute of Neurological Disorders and Stroke (NINDS) Myotatic Reflex Scale. To evaluate the role of training in using the scale, the neurologists randomly and blindly evaluated a total of 80 patients, 40 before and 40 after a training session. Inter- and intraobserver reliability were measured with kappa statistics. Our results showed substantial to near-perfect intraobserver reliability, and moderate-to-substantial interobserver reliability of the NINDS Myotatic Reflex Scale. The reproducibility was better for reflexes in the lower than in the upper extremities. Neither educational background nor the training session influenced the reliability of our results. The NINDS Myotatic Reflex Scale has sufficient reliability to be adopted as a universal scale.

  6. Software reliability models for critical applications

    Pham, H.; Pham, M.


    This report presents the results of the first phase of the ongoing EG&G Idaho, Inc. Software Reliability Research Program. The program is studying the existing software reliability models and proposes a state-of-the-art software reliability model that is relevant to the nuclear reactor control environment. This report consists of three parts: (1) summaries of the literature review of existing software reliability and fault tolerant software reliability models and their related issues, (2) proposed technique for software reliability enhancement, and (3) general discussion and future research. The development of this proposed state-of-the-art software reliability model will be performed in the second place. 407 refs., 4 figs., 2 tabs.

  7. Software reliability models for critical applications

    Pham, H.; Pham, M.


    This report presents the results of the first phase of the ongoing EG G Idaho, Inc. Software Reliability Research Program. The program is studying the existing software reliability models and proposes a state-of-the-art software reliability model that is relevant to the nuclear reactor control environment. This report consists of three parts: (1) summaries of the literature review of existing software reliability and fault tolerant software reliability models and their related issues, (2) proposed technique for software reliability enhancement, and (3) general discussion and future research. The development of this proposed state-of-the-art software reliability model will be performed in the second place. 407 refs., 4 figs., 2 tabs.

  8. Reliability and radiation effects in compound semiconductors

    Johnston, Allan


    This book discusses reliability and radiation effects in compound semiconductors, which have evolved rapidly during the last 15 years. Johnston's perspective in the book focuses on high-reliability applications in space, but his discussion of reliability is applicable to high reliability terrestrial applications as well. The book is important because there are new reliability mechanisms present in compound semiconductors that have produced a great deal of confusion. They are complex, and appear to be major stumbling blocks in the application of these types of devices. Many of the reliability problems that were prominent research topics five to ten years ago have been solved, and the reliability of many of these devices has been improved to the level where they can be used for ten years or more with low failure rates. There is also considerable confusion about the way that space radiation affects compound semiconductors. Some optoelectronic devices are so sensitive to damage in space that they are very difficu...

  9. Short Interest and Stock Returns

    Paul Asquith; Pathak, Parag A.; Jay R. Ritter


    Using a longer time period and both NYSE-Amex and Nasdaq stocks, this paper examines short interest and stock returns in more detail than any previous study and finds that many documented patterns are not robust. While equally weighted high short interest portfolios generally underperform, value weighted portfolios do not. In addition, there is a negative correlation between market returns and short interest over our whole period. Finally, inferences from short time periods, such as 1988-1994...

  10. Judgment of Line Orientation: An Examination of Eight Short Forms

    Spencer, Robert J.; Wendell, Carrington R.; Giggey, Paul P.; Seliger, Stephen L.; Katzel, Leslie I.; Waldstein, Shari R.


    The Judgment of Line Orientation (JLO) test is a commonly used measure of visuospatial perception. Because of its length, several short forms have appeared in the literature. We examined the internal consistency of the JLO and eight of its published short forms among 128 undergraduates, 203 healthy older adults, and 55 chronic kidney disease patients. The full test demonstrated good reliability for traditional neuropsychological assessment, but the majority of short forms were adequate only for screening purposes, where greater measurement error is typically permitted in exchange for brevity. In contrast, a recently developed short form based upon item response theory (Calamia, Markon, Denburg, & Tranel, 2011) demonstrated promise as a stand-alone measure. PMID:23350928

  11. Short fiber reinforced thermoplastic blends

    Malchev, P.G.


    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  12. Short fiber reinforced thermoplastic blends

    Malchev, P.G.


    The present thesis investigates the potential of short fiber reinforced thermoplastic blends, a combination of an immiscible polymer blend and a short fiber reinforced composite, to integrate the easy processing solutions available for short fiber reinforced composites with the high mechanical perfo

  13. Short duration gamma ray bursts

    Patrick Das Gupta


    After a short review of gamma ray bursts (GRBs), we discuss the physical implications of strong statistical correlations seen among some of the parameters of short duration bursts (90 < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.

  14. 76 FR 42534 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits; System...


    ... Reliability Operating Limits; System Restoration Reliability Standards AGENCY: Federal Energy Regulatory... necessary to analyze and monitor Interconnection Reliability Operating Limits (IROL) within its Wide-Area... Interconnection Reliability Operating Limits, Order No. 748, 134 FERC ] 61,213 (2011). \\2\\ The term...

  15. Oxytocin: a short review

    P. F. Levay


    Full Text Available Oxytocin is traditionally associated with parturition and lactation. The similarity in oxytocin plasma levels in males and females implies a wider physiological role for the hormone. Oxytocin would now appear to be involved not only in milk ejection, but also in the production of milk. The hormone has further been shown to play a paracrine role in menstruation and to be of importance for normal fertilisation. Several endocrine modulatory as well as neurotransmitter effects have also been reported for oxytocin. The discovery of the role of oxytocin in central nervous system processes such as pain, anxiety, memory and learning has stimuluted a search for possible therapeutic applications of oxytocin in cases such as chronic pain and Alzheimer’s disease. A short review is presented of some of the biochemical and physiological aspects underlying the functions and possible therapeutic applications of oxytocin.

  16. Behavioral ecology, endocrinology and signal reliability of electric communication

    Gavassa, Sat; Goldina, Anna; Silva, Ana C.; Stoddard, Philip K.


    Summary The balance between the costs and benefits of conspicuous animal communication signals ensures that signal expression relates to the quality of the bearer. Signal plasticity enables males to enhance conspicuous signals to impress mates and competitors and to reduce signal expression to lower energetic and predation-related signaling costs when competition is low. While signal plasticity may benefit the signaler, it can compromise the reliability of the information conveyed by the signals. In this paper we review the effect of signal plasticity on the reliability of the electrocommunication signal of the gymnotiform fish Brachyhypopomus gauderio. We (1) summarize the endocrine regulation of signal plasticity, (2) explore the regulation of signal plasticity in females, (3) examine the information conveyed by the signal, (4) show how that information changes when the signal changes, and (5) consider the energetic strategies used to sustain expensive signaling. The electric organ discharge (EOD) of B. gauderio changes in response to social environment on two time scales. Two hormone classes, melanocortins and androgens, underlie the short-term and long-term modulation of signal amplitude and duration observed during social interaction. Population density drives signal amplitude enhancement, unexpectedly improving the reliability with which the signal predicts the signaler's size. The signal's second phase elongation predicts androgen levels and male reproductive condition. Males sustain signal enhancement with dietary intake, but when food is limited, they ‘go for broke’ and put extra energy into electric signals. Cortisol diminishes EOD parameters, but energy-limited males offset cortisol effects by boosting androgen levels. While physiological constraints are sufficient to maintain signal amplitude reliability, phenotypic integration and signaling costs maintain reliability of signal duration, consistent with theory of honest signaling. PMID:23761465

  17. Short QT syndrome.

    Schimpf, Rainer; Wolpert, Christian; Gaita, Fiorenzo; Giustetto, Carla; Borggrefe, Martin


    The short QT syndrome constitutes a new clinical entity that is associated with a high incidence of sudden cardiac death, syncope, and/or atrial fibrillation even in young patients and newborns. Patients with this congenital electrical abnormality are characterized by rate-corrected QT intervalsdelayed-rectifier current I(Kr) have been identified in the first two reported families with familial sudden cardiac death. Recently, two further gain-of-function mutations in the KCNQ1 gene encoding the alpha-subunit of the KvLQT1 (I(Ks)) channel and in the KCNJ2 gene encoding the strong inwardly rectifying channel protein Kir2.1 confirmed a genetically heterogeneous disease. The possible substrate for the development of ventricular tachyarrhythmias may be a significant transmural dispersion of the repolarisation due to a heterogeneous abbreviation of the action potential duration. The implantable cardioverter defibrillator is the therapy of choice in patients with syncope and a positive family history of sudden cardiac death. However, ICD therapy in patients with a short QT syndrome has an increased risk for inappropriate shock therapies due to possible T wave oversensing. The impact of sotalol, ibutilide, flecainide, and quinidine on QT prolongation has been evaluated, but only quinidine effectively suppressed gain-of-function in I(Kr) with prolongation of the QT interval. In patients with a mutation in HERG, it rendered ventricular tachycardias/ventricular fibrillation non-inducible and restored the QT interval/heart rate relationship towards a normal range. It may serve as an adjunct to ICD therapy or as a possible alternative treatment, especially for children and newborns.

  18. [Trust and reliability in surgery].

    Weigel, T F; Hanisch, E; Buia, A; Hessler, C


    Social interactions are hardly possible without trust. Medical and in particular surgical actions can change the lives of people directly and indirectly existentially. Thus, the relationship between doctor and patient is a special form of social interaction, and will be hard to find anywhere else. The nature of the doctor-patient relationship also determines the success of a treatment. The core and the importance of trust, as a central part of this relationship, will be reconstructed in the present paper. The increasing possibilities of information acquisition in modern societies, and the ever-present need for transparency, impact more and more on the doctor-patient relationship. At first glance, concepts of trust seem to be of secondary importance. The current developments regarding the remuneration of services in the medical system likewise bear the risk to increasingly determine the importance of trust in the doctor-patient relationship. However, it is necessary to delineate reliability from trust. Due to the conditions which are constitutive for the operational disciplines, a climate of trust, even in a modern information society, is more necessary than ever.

  19. Reliability of analog quantum simulation

    Sarovar, Mohan [Sandia National Laboratories, Digital and Quantum Information Systems, Livermore, CA (United States); Zhang, Jun; Zeng, Lishan [Shanghai Jiao Tong University, Joint Institute of UMich-SJTU, Key Laboratory of System Control and Information Processing (MOE), Shanghai (China)


    Analog quantum simulators (AQS) will likely be the first nontrivial application of quantum technology for predictive simulation. However, there remain questions regarding the degree of confidence that can be placed in the results of AQS since they do not naturally incorporate error correction. Specifically, how do we know whether an analog simulation of a quantum model will produce predictions that agree with the ideal model in the presence of inevitable imperfections? At the same time there is a widely held expectation that certain quantum simulation questions will be robust to errors and perturbations in the underlying hardware. Resolving these two points of view is a critical step in making the most of this promising technology. In this work we formalize the notion of AQS reliability by determining sensitivity of AQS outputs to underlying parameters, and formulate conditions for robust simulation. Our approach naturally reveals the importance of model symmetries in dictating the robust properties. To demonstrate the approach, we characterize the robust features of a variety of quantum many-body models. (orig.)

  20. Chapter 15: Reliability of Wind Turbines

    Sheng, Shuangwen; O' Connor, Ryan


    The global wind industry has witnessed exciting developments in recent years. The future will be even brighter with further reductions in capital and operation and maintenance costs, which can be accomplished with improved turbine reliability, especially when turbines are installed offshore. One opportunity for the industry to improve wind turbine reliability is through the exploration of reliability engineering life data analysis based on readily available data or maintenance records collected at typical wind plants. If adopted and conducted appropriately, these analyses can quickly save operation and maintenance costs in a potentially impactful manner. This chapter discusses wind turbine reliability by highlighting the methodology of reliability engineering life data analysis. It first briefly discusses fundamentals for wind turbine reliability and the current industry status. Then, the reliability engineering method for life analysis, including data collection, model development, and forecasting, is presented in detail and illustrated through two case studies. The chapter concludes with some remarks on potential opportunities to improve wind turbine reliability. An owner and operator's perspective is taken and mechanical components are used to exemplify the potential benefits of reliability engineering analysis to improve wind turbine reliability and availability.

  1. Snaith-Hamilton Pleasure Scale: Validity, reliability, pyscometric characteristics in our society

    Sermin Kesebir


    Conclusion: It is stated that SHPS distinguishes the cases diagnosed with BD and MDD from healthy individuals. Turkish forms of SHPS is valid and reliable instrument, also short, simple, based on self report and easy to apply. [Cukurova Med J 2015; 40(2.000: 252-257

  2. Reliability and validity of measurements of facial swelling with a stereophotogrammetry optical three-dimensional scanner

    van der Meer, Wicher J.; Dijkstra, Pieter U.; Visser, Anita; Vissink, Arjan; Ren, Yijin


    Volume changes in facial morphology can be assessed using the 3dMD DSP400 stereo-optical 3-dimensional scanner, which uses visible light and has a short scanning time. Its reliability and validity have not to our knowledge been investigated for the assessment of facial swelling. Our aim therefore wa

  3. Fundamental mechanisms of micromachine reliability



    Due to extreme surface to volume ratios, adhesion and friction are critical properties for reliability of Microelectromechanical Systems (MEMS), but are not well understood. In this LDRD the authors established test structures, metrology and numerical modeling to conduct studies on adhesion and friction in MEMS. They then concentrated on measuring the effect of environment on MEMS adhesion. Polycrystalline silicon (polysilicon) is the primary material of interest in MEMS because of its integrated circuit process compatibility, low stress, high strength and conformal deposition nature. A plethora of useful micromachined device concepts have been demonstrated using Sandia National Laboratories' sophisticated in-house capabilities. One drawback to polysilicon is that in air the surface oxidizes, is high energy and is hydrophilic (i.e., it wets easily). This can lead to catastrophic failure because surface forces can cause MEMS parts that are brought into contact to adhere rather than perform their intended function. A fundamental concern is how environmental constituents such as water will affect adhesion energies in MEMS. The authors first demonstrated an accurate method to measure adhesion as reported in Chapter 1. In Chapter 2 through 5, they then studied the effect of water on adhesion depending on the surface condition (hydrophilic or hydrophobic). As described in Chapter 2, they find that adhesion energy of hydrophilic MEMS surfaces is high and increases exponentially with relative humidity (RH). Surface roughness is the controlling mechanism for this relationship. Adhesion can be reduced by several orders of magnitude by silane coupling agents applied via solution processing. They decrease the surface energy and render the surface hydrophobic (i.e. does not wet easily). However, only a molecular monolayer coats the surface. In Chapters 3-5 the authors map out the extent to which the monolayer reduces adhesion versus RH. They find that adhesion is

  4. Reliability Growth in Space Life Support Systems

    Jones, Harry W.


    A hardware system's failure rate often increases over time due to wear and aging, but not always. Some systems instead show reliability growth, a decreasing failure rate with time, due to effective failure analysis and remedial hardware upgrades. Reliability grows when failure causes are removed by improved design. A mathematical reliability growth model allows the reliability growth rate to be computed from the failure data. The space shuttle was extensively maintained, refurbished, and upgraded after each flight and it experienced significant reliability growth during its operational life. In contrast, the International Space Station (ISS) is much more difficult to maintain and upgrade and its failure rate has been constant over time. The ISS Carbon Dioxide Removal Assembly (CDRA) reliability has slightly decreased. Failures on ISS and with the ISS CDRA continue to be a challenge.

  5. Structural Reliability of Wind Turbine Blades

    Dimitrov, Nikolay Krasimirov

    by developing new models and standards or carrying out tests The following aspects are covered in detail: ⋅ The probabilistic aspects of ultimate strength of composite laminates are addressed. Laminated plates are considered as a general structural reliability system where each layer in a laminate is a separate...... system component. Methods for solving the system reliability are discussed in an example problem. ⋅ Probabilistic models for fatigue life of laminates and sandwich core are developed and calibrated against measurement data. A modified, nonlinear S-N relationship is formulated where the static strength...... the reliability against several modes of failure in two different structures. This includes reliability against blade-tower collision, and the reliability against ultimate and fatigue failure of a sandwich panel. The results from the reliability analyses are then used for calibrating partial safety factors...

  6. Combination of structural reliability and interval analysis

    Zhiping Qiu; Di Yang; saac Elishakoff


    In engineering applications,probabilistic reliability theory appears to be presently the most important method,however,in many cases precise probabilistic reliability theory cannot be considered as adequate and credible model of the real state of actual affairs.In this paper,we developed a hybrid of probabilistic and non-probabilistic reliability theory,which describes the structural uncertain parameters as interval variables when statistical data are found insufficient.By using the interval analysis,a new method for calculating the interval of the structural reliability as well as the reliability index is introduced in this paper,and the traditional probabilistic theory is incorporated with the interval analysis.Moreover,the new method preserves the useful part of the traditional probabilistic reliability theory,but removes the restriction of its strict requirement on data acquisition.Example is presented to demonstrate the feasibility and validity of the proposed theory.

  7. Structural reliability codes for probabilistic design

    Ditlevsen, Ove Dalager


    difficulties of ambiguity and definition show up when attempting to make the transition from a given authorized partial safety factor code to a superior probabilistic code. For any chosen probabilistic code format there is a considerable variation of the reliability level over the set of structures defined...... considerable variation of the reliability measure as defined by a specific probabilistic code format. Decision theoretical principles are applied to get guidance about which of these different reliability levels of existing practice to choose as target reliability level. Moreover, it is shown that the chosen...... probabilistic code format has not only strong influence on the formal reliability measure, but also on the formal cost of failure to be associated if a design made to the target reliability level is considered to be optimal. In fact, the formal cost of failure can be different by several orders of size for two...

  8. Solid State Lighting Reliability Components to Systems

    Fan, XJ


    Solid State Lighting Reliability: Components to Systems begins with an explanation of the major benefits of solid state lighting (SSL) when compared to conventional lighting systems including but not limited to long useful lifetimes of 50,000 (or more) hours and high efficacy. When designing effective devices that take advantage of SSL capabilities the reliability of internal components (optics, drive electronics, controls, thermal design) take on critical importance. As such a detailed discussion of reliability from performance at the device level to sub components is included as well as the integrated systems of SSL modules, lamps and luminaires including various failure modes, reliability testing and reliability performance. This book also: Covers the essential reliability theories and practices for current and future development of Solid State Lighting components and systems Provides a systematic overview for not only the state-of-the-art, but also future roadmap and perspectives of Solid State Lighting r...

  9. Creating Highly Reliable Accountable Care Organizations.

    Vogus, Timothy J; Singer, Sara J


    Accountable Care Organizations' (ACOs) pursuit of the triple aim of higher quality, lower cost, and improved population health has met with mixed results. To improve the design and implementation of ACOs we look to organizations that manage similarly complex, dynamic, and tightly coupled conditions while sustaining exceptional performance known as high-reliability organizations. We describe the key processes through which organizations achieve reliability, the leadership and organizational practices that enable it, and the role that professionals can play when charged with enacting it. Specifically, we present concrete practices and processes from health care organizations pursuing high-reliability and from early ACOs to illustrate how the triple aim may be met by cultivating mindful organizing, practicing reliability-enhancing leadership, and identifying and supporting reliability professionals. We conclude by proposing a set of research questions to advance the study of ACOs and high-reliability research.

  10. PV Systems Reliability Final Technical Report.

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Benjamin Bing-Yeh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  11. Reliability analysis of an associated system

    陈长杰; 魏一鸣; 蔡嗣经


    Based on engineering reliability of large complex system and distinct characteristic of soft system, some new conception and theory on the medium elements and the associated system are created. At the same time, the reliability logic model of associated system is provided. In this paper, through the field investigation of the trial operation, the engineering reliability of the paste fill system in No.2 mine of Jinchuan Non-ferrous Metallic Corporation is analyzed by using the theory of associated system.

  12. Advances in reliability and system engineering

    Davim, J


    This book presents original studies describing the latest research and developments in the area of reliability and systems engineering. It helps the reader identifying gaps in the current knowledge and presents fruitful areas for further research in the field. Among others, this book covers reliability measures, reliability assessment of multi-state systems, optimization of multi-state systems, continuous multi-state systems, new computational techniques applied to multi-state systems and probabilistic and non-probabilistic safety assessment.

  13. Sensitivity Analysis for the System Reliability Function


    reliabilities. The unique feature of the approach is that stunple data collected on K inde-ndent replications using a specified component reliability % v &:•r...Carlo method. The polynomial time algorithm of Agrawaw Pad Satyanarayana (104) fIr the exact reliability computaton for seres- allel systems exemplifies...consideration. As an example for the s-t connectedness problem, let denote -7- edge-disjoint minimal s-t paths of G and let V , denote edge-disjoint

  14. Reliability engineering in solar energy: workshop proceedings

    Gross, G.


    A workshop to reveal the scope of reliability-related activities in solar energy conversion projects and in nonsolar segments of industry is described. Two reliability programs, one in heating and cooling and one in photovoltaics, are explicated. This document also presents general suggestions for the establishment of a unified program for reliability, durability, maintainability, and safety (RDM and S) in present and future solar projects.

  15. Delivery Time Reliability Model of Logistics Network

    Liusan Wu; Qingmei Tan; Yuehui Zhang


    Natural disasters like earthquake and flood will surely destroy the existing traffic network, usually accompanied by delivery delay or even network collapse. A logistics-network-related delivery time reliability model defined by a shortest-time entropy is proposed as a means to estimate the actual delivery time reliability. The less the entropy is, the stronger the delivery time reliability remains, and vice versa. The shortest delivery time is computed separately based on two different assum...

  16. Bayesian Missile System Reliability from Point Estimates


    OCT 2014 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Bayesian Missile System Reliability from Point Estimates 5a. CONTRACT...Principle (MEP) to convert point estimates to probability distributions to be used as priors for Bayesian reliability analysis of missile data, and...illustrate this approach by applying the priors to a Bayesian reliability model of a missile system. 15. SUBJECT TERMS priors, Bayesian , missile

  17. Optimal Reliability-Based Code Calibration

    Sørensen, John Dalsgaard; Kroon, I. B.; Faber, M. H.


    Calibration of partial safety factors is considered in general, including classes of structures where no code exists beforehand. The partial safety factors are determined such that the difference between the reliability for the different structures in the class considered and a target reliability...... level is minimized. Code calibration on a decision theoretical basis is also considered and it is shown how target reliability indices can be calibrated. Results from code calibration for rubble mound breakwater designs are shown....

  18. Estimation of the Reliability of Distributed Applications

    Marian Pompiliu CRISTESCU; Laurentiu CIOVICA


    In this paper the reliability is presented as an important feature for use in mission-critical distributed applications. Certain aspects of distributed systems make the requested level of reliability more difficult. An obvious benefit of distributed systems is that they serve the global business and social environment in which we live and work. Another benefit is that they can improve the quality of services, in terms of reliability, availability and performance, for the complex systems. The ...

  19. Quality and Reliability of Missile System

    Mr. Prahlada


    Full Text Available Missile system is a single-shot weapon system which requires very high quality and reliability. Therefore, quality and reliability have to be built into the system from designing to testing and evaluation. In this paper, the technological challenges encountered during development of operational missile system and the factors considered to build quality and reliability through the design, manufacture, assembly, testing and by sharing the knowledge with other aerospace agencies, industries and institutions, etc. have been presented.

  20. Reliability engineering in solar energy: workshop proceedings

    Gross, G.


    A workshop to reveal the scope of reliability-related activities in solar energy conversion projects and in nonsolar segments of industry is described. Two reliability programs, one in heating and cooling and one in photovoltaics, are explicated. This document also presents general suggestions for the establishment of a unified program for reliability, durability, maintainability, and safety (RDM and S) in present and future solar projects.

  1. Reliability based design optimization: Formulations and methodologies

    Agarwal, Harish

    Modern products ranging from simple components to complex systems should be designed to be optimal and reliable. The challenge of modern engineering is to ensure that manufacturing costs are reduced and design cycle times are minimized while achieving requirements for performance and reliability. If the market for the product is competitive, improved quality and reliability can generate very strong competitive advantages. Simulation based design plays an important role in designing almost any kind of automotive, aerospace, and consumer products under these competitive conditions. Single discipline simulations used for analysis are being coupled together to create complex coupled simulation tools. This investigation focuses on the development of efficient and robust methodologies for reliability based design optimization in a simulation based design environment. Original contributions of this research are the development of a novel efficient and robust unilevel methodology for reliability based design optimization, the development of an innovative decoupled reliability based design optimization methodology, the application of homotopy techniques in unilevel reliability based design optimization methodology, and the development of a new framework for reliability based design optimization under epistemic uncertainty. The unilevel methodology for reliability based design optimization is shown to be mathematically equivalent to the traditional nested formulation. Numerical test problems show that the unilevel methodology can reduce computational cost by at least 50% as compared to the nested approach. The decoupled reliability based design optimization methodology is an approximate technique to obtain consistent reliable designs at lesser computational expense. Test problems show that the methodology is computationally efficient compared to the nested approach. A framework for performing reliability based design optimization under epistemic uncertainty is also developed

  2. The short and very short forms of the Children's Behavior Questionnaire in a community sample of preschoolers.

    de la Osa, Nuria; Granero, Roser; Penelo, Eva; Domènech, Josep M; Ezpeleta, Lourdes


    The aim was to test the internal structure of scores on the short and very short forms of the Children's Behavior Questionnaire (CBQ) scale and to study the relationship between the dimensions derived and external variables previously related to extreme temperament in a Spanish community sample. The sample comprised of 622 three-year-old children participating in a longitudinal study. Data were obtained from parents and teachers through a semistructured diagnostic interview and questionnaires evaluating children's characteristics and psychological states. Results showed a three-factor structure and moderate reliability of the scale scores for both the short and very short forms. Associations were found between the Surgency/Extraversion dimension and attention-deficit/hyperactivity disorder and externalizing problems, between Negative Affect and internalizing and emotional problems, and between Effortful Control and attention, externalizing, and social problems and other executive function measures. Salient temperamental characteristics predicted psychopathological disorders and impairment at ages 3 and 4. The short forms of the CBQ provide reliable and valid scores for assessing temperamental characteristics in the preschool years. © The Author(s) 2013.

  3. Reliability of power output during eccentric sprint cycling.

    Brughelli, Matt; Van Leemputte, Marc


    The purpose of this study was to determine the reliability of power outputs during maximal intensity eccentric cycling over short durations (i.e., eccentric sprint cycling) on a "motor-driven" isokinetic ergometer. Fourteen physically active male subjects performed isokinetic eccentric cycling sprints at 40, 60, 80, 100, and 120 revolutions per minute (rpm) on 4 separate occasions (T1-T4). Each sprint lasted for 6 seconds, and absolute measures of mean power (MP) and peak power (PP) per revolution were recorded. Significant increases in MP and PP were observed between T1 and subsequent trials, but no significant differences were identified between T2, T3, and T4. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated to reflect within-subject and between-session reliability of MP and PP at each cadence. The CV improved to below 10% for cadences of 60, 80, 100, and 120 rpm between T3 and T4, and the majority of ICC values improved to above 0.90. The remaining ICC values remained in the moderate range between T3 and T4 (i.e., 0.82-0.89). Coefficient of variation and ICC values for the 40 rpm cadence remained at unacceptable levels throughout the 4 trials and thus should be avoided in future investigations. The results of this study indicate that reliable power outputs may be obtained after 2 familiarization sessions during eccentric sprint cycling at cadences ranging from 60 to 120 rpm.

  4. Reliability Survey of Military Acquisition Systems


    software-intensive sensor and weapons systems, ensuring that there are no open Category 1 or 2 deficiency reports prior to OT. There is also evidence...reliability growth curve used to develop intermediate reliability goal(s)? 5c3 Are the reliability growth goal(s) linked to OTs (e.g., IOT &E, FOT&E...the reliability growth potential? 8 Did your program have an operational test in FY12? 8a What type of operational test was it? (DT/OT, OA/LUT, IOT &E

  5. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  6. Reliability and Availability of Cloud Computing

    Bauer, Eric


    A holistic approach to service reliability and availability of cloud computing Reliability and Availability of Cloud Computing provides IS/IT system and solution architects, developers, and engineers with the knowledge needed to assess the impact of virtualization and cloud computing on service reliability and availability. It reveals how to select the most appropriate design for reliability diligence to assure that user expectations are met. Organized in three parts (basics, risk analysis, and recommendations), this resource is accessible to readers of diverse backgrounds and experience le

  7. Integrated reliability program for Scout research vehicle.

    Morris, B. V.; Welch, R. C.


    Integrated reliability program for Scout launch vehicle in terms of design specification, review functions, malfunction reporting, failed parts analysis, quality control, standardization and certification

  8. Reliability of large and complex systems

    Kolowrocki, Krzysztof


    Reliability of Large and Complex Systems, previously titled Reliability of Large Systems, is an innovative guide to the current state and reliability of large and complex systems. In addition to revised and updated content on the complexity and safety of large and complex mechanisms, this new edition looks at the reliability of nanosystems, a key research topic in nanotechnology science. The author discusses the importance of safety investigation of critical infrastructures that have aged or have been exposed to varying operational conditions. This reference provides an asympt

  9. Reliability-Based Topology Optimization With Uncertainties

    Bae, Kyoungryun [JAEIK Information and Communication Co. Ltd., Seoul (Korea, Republic of); Wang, Semyung [Kwangju Institute of Science and Technology, Kwangju (Korea, Republic of); Choi, Kyung K. [Univ. of Iowa, Iowa (United States)


    A probabilistic optimal design modeled with finite elements is presented. A 2-D finite element model is constructed for topology optimization. Young's modulus, thickness and loading are considered as uncertain variables. The uncertain variable means that the variable has a variance on a certain point. In order to compute reliability constraints, two methods-RIA, PMA-are widely used. To find reliability index easily, the limit state function is linearly approximated at the each iteration. This approximation method is called as the first order reliability method (FORM), which is widely used in reliability based design optimizations (RBDO)

  10. Maximum phonation time: variability and reliability.

    Speyer, Renée; Bogaardt, Hans C A; Passos, Valéria Lima; Roodenburg, Nel P H D; Zumach, Anne; Heijnen, Mariëlle A M; Baijens, Laura W J; Fleskens, Stijn J H M; Brunings, Jan W


    The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia versus a group of healthy control subjects matched by age and gender. Over a period of maximally 6 weeks, three video recordings were made of five subjects' maximum phonation time trials. A panel of five experts were responsible for all measurements, including a repeated measurement of the subjects' first recordings. Patients showed significantly shorter maximum phonation times compared with healthy controls (on average, 6.6 seconds shorter). The averaged interclass correlation coefficient (ICC) over all raters per trial for the first day was 0.998. The averaged reliability coefficient per rater and per trial for repeated measurements of the first day's data was 0.997, indicating high intrarater reliability. The mean reliability coefficient per day for one trial was 0.939. When using five trials, the reliability increased to 0.987. The reliability over five trials for a single day was 0.836; for 2 days, 0.911; and for 3 days, 0.935. To conclude, the maximum phonation time has proven to be a highly reliable measure in voice assessment. A single rater is sufficient to provide highly reliable measurements.

  11. Mission Reliability Estimation for Repairable Robot Teams

    Stephen B. Stancliff


    Full Text Available Many of the most promising applications for mobile robots require very high reliability. The current generation of mobile robots is, for the most part, highly unreliable. The few mobile robots that currently demonstrate high reliability achieve this reliability at a high financial cost. In order for mobile robots to be more widely used, it will be necessary to find ways to provide high mission reliability at lower cost. Comparing alternative design paradigms in a principled way requires methods for comparing the reliability of different robot and robot team configurations. In this paper, we present the first principled quantitative method for performing mission reliability estimation for mobile robot teams. We also apply this method to an example robot mission, examining the cost-reliability tradeoffs among different team configurations. Using conservative estimates of the cost-reliability relationship, our results show that it is possible to significantly reduce the cost of a robotic mission by using cheaper, lower-reliability components and providing spares.

  12. Design for Reliability of Power Electronic Systems

    Wang, Huai; Ma, Ke; Blaabjerg, Frede


    Advances in power electronics enable efficient and flexible processing of electric power in the application of renewable energy sources, electric vehicles, adjustable-speed drives, etc. More and more efforts are devoted to better power electronic systems in terms of reliability to ensure high...... on a 2.3 MW wind power converter is discussed with emphasis on the reliability critical components IGBTs. Different aspects of improving the reliability of the power converter are mapped. Finally, the challenges and opportunities to achieve more reliable power electronic systems are addressed....

  13. NEPP DDR Device Reliability FY13 Report

    Guertin, Steven M.; Armbar, Mehran


    This document reports the status of the NEPP Double Data Rate (DDR) Device Reliability effort for FY2013. The task targeted general reliability of > 100 DDR2 devices from Hynix, Samsung, and Micron. Detailed characterization of some devices when stressed by several data storage patterns was studied, targeting ability of the data cells to store the different data patterns without refresh, highlighting the weakest bits. DDR2, Reliability, Data Retention, Temperature Stress, Test System Evaluation, General Reliability, IDD measurements, electronic parts, parts testing, microcircuits

  14. Measuring reliability under epistemic uncertainty:Review on non-probabilistic reliability metrics

    Kang Rui; Zhang Qingyuan; Zeng Zhiguo; Enrico Zio; Li Xiaoyang


    In this paper, a systematic review of non-probabilistic reliability metrics is conducted to assist the selection of appropriate reliability metrics to model the influence of epistemic uncertainty. Five frequently used non-probabilistic reliability metrics are critically reviewed, i.e., evidence-theory-based reliability metrics, interval-analysis-based reliability metrics, fuzzy-interval-analysis-based reliability metrics, possibility-theory-based reliability metrics (posbist reliability) and uncertainty-theory-based reliability metrics (belief reliability). It is pointed out that a qualified reli-ability metric that is able to consider the effect of epistemic uncertainty needs to (1) compensate the conservatism in the estimations of the component-level reliability metrics caused by epistemic uncertainty, and (2) satisfy the duality axiom, otherwise it might lead to paradoxical and confusing results in engineering applications. The five commonly used non-probabilistic reliability metrics are compared in terms of these two properties, and the comparison can serve as a basis for the selection of the appropriate reliability metrics.

  15. Reliability and criterion validity of an observation protocol for working technique assessments in cash register work.

    Palm, Peter; Josephson, Malin; Mathiassen, Svend Erik; Kjellberg, Katarina


    We evaluated the intra- and inter-observer reliability and criterion validity of an observation protocol, developed in an iterative process involving practicing ergonomists, for assessment of working technique during cash register work for the purpose of preventing upper extremity symptoms. Two ergonomists independently assessed 17 15-min videos of cash register work on two occasions each, as a basis for examining reliability. Criterion validity was assessed by comparing these assessments with meticulous video-based analyses by researchers. Intra-observer reliability was acceptable (i.e. proportional agreement >0.7 and kappa >0.4) for 10/10 questions. Inter-observer reliability was acceptable for only 3/10 questions. An acceptable inter-observer reliability combined with an acceptable criterion validity was obtained only for one working technique aspect, 'Quality of movements'. Thus, major elements of the cashiers' working technique could not be assessed with an acceptable accuracy from short periods of observations by one observer, such as often desired by practitioners. Practitioner Summary: We examined an observation protocol for assessing working technique in cash register work. It was feasible in use, but inter-observer reliability and criterion validity were generally not acceptable when working technique aspects were assessed from short periods of work. We recommend the protocol to be used for educational purposes only.

  16. Reducing the Risk of Damage to Power Transformers of 110 kV and Above Accompanying Internal Short Circuits

    L’vova, M. M. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); L’vov, S. Yu. [Presselektro LLC (Russian Federation); Komarov, V. B. [IPCE RAS (Russian Federation); Lyut’ko, E. O. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation); Vdoviko, V. P. [EMA Ltd. (Russian Federation); Demchenko, V. V. [JSC “Boguchanskaya HPP” (Russian Federation); Belyaev, S. G. [PKF Konif Ltd. (Russian Federation); Savel’ev, V. A. [Ivanovo State Power University (Russian Federation); L’vov, M. Yu., E-mail:; L’vov, Yu. N. [JSC “R& D Center at Federal Grid Company of the Unified Power System” (Russian Federation)


    Methods of increasing the operating reliability of power transformers, autotransformers and shunting reactors in order to reduce the risk of damage, which accompany internal short circuits and equipment fires and explosions, are considered.

  17. Newnes short wave listening handbook

    Pritchard, Joe


    Newnes Short Wave Listening Handbook is a guide for starting up in short wave listening (SWL). The book is comprised of 15 chapters that discuss the basics and fundamental concepts of short wave radio listening. The coverage of the text includes electrical principles; types of signals that can be heard in the radio spectrum; and using computers in SWL. The book also covers SWL equipment, such as receivers, converters, and circuits. The text will be of great use to individuals who want to get into short wave listening.

  18. Reliability evaluation for offshore wind farms

    Zhao, Menghua; Blåbjerg, Frede; Chen, Zhe


    In this paper, a new reliability index - Loss Of Generation Ratio Probability (LOGRP) is proposed for evaluating the reliability of an electrical system for offshore wind farms, which emphasizes the design of wind farms rather than the adequacy for specific load demand. A practical method...... to calculate LOGRP of offshore wind farms is proposed and evaluated....

  19. Scale Reliability Evaluation with Heterogeneous Populations

    Raykov, Tenko; Marcoulides, George A.


    A latent variable modeling approach for scale reliability evaluation in heterogeneous populations is discussed. The method can be used for point and interval estimation of reliability of multicomponent measuring instruments in populations representing mixtures of an unknown number of latent classes or subpopulations. The procedure is helpful also…

  20. Immodest Witnesses: Reliability and Writing Assessment

    Gallagher, Chris W.


    This article offers a survey of three reliability theories in writing assessment: positivist, hermeneutic, and rhetorical. Drawing on an interdisciplinary investigation of the notion of "witnessing," this survey emphasizes the kinds of readers and readings each theory of reliability produces and the epistemological grounds on which it…

  1. Reliability in Cross-National Content Analysis.

    Peter, Jochen; Lauf, Edmund


    Investigates how coder characteristics such as language skills, political knowledge, coding experience, and coding certainty affected inter-coder and coder-training reliability. Shows that language skills influenced both reliability types. Suggests that cross-national researchers should pay more attention to cross-national assessments of…

  2. Response and Reliability Problems of Dynamic Systems

    Nielsen, Søren R. K.

    The present thesis consists of selected parts of the work performed by the author on stochastic dynamics and reliability theory of dynamically excited structures primarily during the period 1986-1996.......The present thesis consists of selected parts of the work performed by the author on stochastic dynamics and reliability theory of dynamically excited structures primarily during the period 1986-1996....

  3. 76 FR 66229 - Transmission Planning Reliability Standards


    ... planning process. The table includes a footnote regarding planned or controlled interruption of electric supply where a single contingency occurs on a transmission system. North American Electric Reliability...\\ Reliability Standard TPL-002-0a, Requirement R1. Planned or controlled interruption of electric supply to...

  4. Software architecture reliability analysis using failure scenarios

    Tekinerdogan, Bedir; Sozer, Hasan; Aksit, Mehmet


    With the increasing size and complexity of software in embedded systems, software has now become a primary threat for the reliability. Several mature conventional reliability engineering techniques exist in literature but traditionally these have primarily addressed failures in hardware components a

  5. Towards Reliable Integrated Services for Dependable Systems

    Schiøler, Henrik; Ravn, Anders Peter; Izadi-Zamanabadi, Roozbeh


    Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical...

  6. Reliability assessment of wave Energy devices

    Ambühl, Simon; Kramer, Morten; Kofoed, Jens Peter


    Energy from waves may play a key role in sustainable electricity production in the future. Optimal reliability levels for components used for Wave Energy Devices (WEDs) need to be defined to be able to decrease their cost of electricity. Optimal reliability levels can be found using probabilistic...

  7. System Reliability Assessment of Offshore Pipelines

    Mustaffa, Z.


    The title of this thesis, System Reliability Assessment of Offshore Pipelines, portrays the application of probabilistic methods in assessing the reliability of these structures. The main intention of this thesis is to identify, apply and judge the suitability of the probabilistic methods in evalua

  8. Structural reliability of existing city bridges

    Hellebrandt, L.; Steenbergen, R.; Vrouwenvelder, T.; Blom, K.


    Full probabilistic reliability analysis may be valuable for assessing existing structures. Measures for increasing the safety level are quite costly for existing structures and may be unnecessary when such a decision is grounded on a conservative analysis for determining the structural reliability.

  9. Calculation reliability in vehicle accident reconstruction.

    Wach, Wojciech


    The reconstruction of vehicle accidents is subject to assessment in terms of the reliability of a specific system of engineering and technical operations. In the article [26] a formalized concept of the reliability of vehicle accident reconstruction, defined using Bayesian networks, was proposed. The current article is focused on the calculation reliability since that is the most objective section of this model. It is shown that calculation reliability in accident reconstruction is not another form of calculation uncertainty. The calculation reliability is made dependent on modeling reliability, adequacy of the model and relative uncertainty of calculation. All the terms are defined. An example is presented concerning the analytical determination of the collision location of two vehicles on the road in the absence of evidential traces. It has been proved that the reliability of this kind of calculations generally does not exceed 0.65, despite the fact that the calculation uncertainty itself can reach only 0.05. In this example special attention is paid to the analysis of modeling reliability and calculation uncertainty using sensitivity coefficients and weighted relative uncertainty.

  10. Maximum Phonation Time: Variability and Reliability

    R. Speyer; H.C.A. Bogaardt; V.L. Passos; N.P.H.D. Roodenburg; A. Zumach; M.A.M. Heijnen; L.W.J. Baijens; S.J.H.M. Fleskens; J.W. Brunings


    The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia v

  11. Are clickthrough data reliable as image annotations?

    Tsikrika, T.; Diou, C.; Vries, A.P. de; Delopoulos, A.


    We examine the reliability of clickthrough data as concept-based image annotations, by comparing them against manual annotations, for different concept categories. Our analysis shows that, for many concepts, the image annotations generated by using clickthrough data are reliable, with up to 90% of t

  12. A Software Reliability Model Using Quantile Function

    Bijamma Thomas


    Full Text Available We study a class of software reliability models using quantile function. Various distributional properties of the class of distributions are studied. We also discuss the reliability characteristics of the class of distributions. Inference procedures on parameters of the model based on L-moments are studied. We apply the proposed model to a real data set.

  13. Enhancing Energy Efficient TCP by Partial Reliability

    Donckers, L.; Smit, G.J.M.; Smit, L.T.


    We present a study on the effects on a mobile system's energy efficiency of enhancing, with partial reliability, our energy efficient TCP variant (E/sup 2/TCP) (see Donckers, L. et al., Proc. 2nd Asian Int. Mobile Computing Conf. - AMOC2002, p.18-28, 2002). Partial reliability is beneficial for mult

  14. Reliability Based Optimization of Structural Systems

    Sørensen, John Dalsgaard


    The optimization problem to design structural systems such that the reliability is satisfactory during the whole lifetime of the structure is considered in this paper. Some of the quantities modelling the loads and the strength of the structure are modelled as random variables. The reliability...

  15. Reliability polynomials crossing more than twice

    Brown, J.I.; Koç, Y.; Kooij, R.E.


    In this paper we study all-terminal reliability polynomials of networks having the same number of nodes and the same number of links. First we show that the smallest possible size for a pair of networks that allows for two crossings of their reliability polynomials have seven nodes and fifteen edges

  16. 77 FR 26714 - Transmission Planning Reliability Standards


    ... that the Commission remand to the ERO for further consideration a Reliability Standard ``that the... consideration of other improvements contained in proposed Reliability Standard TPL-001-2. \\4\\ Transmission.... RM11-18-000, is unjust and unreasonable, unduly discriminatory or preferential, and not in the...

  17. Towards Reliable Integrated Services for Dependable Systems

    Schiøler, Henrik; Ravn, Anders Peter; Izadi-Zamanabadi, Roozbeh

    Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical...

  18. Reliability and Robustness Analysis of the Masinga Dam under Uncertainty

    Hayden Postle-Floyd


    Full Text Available Kenya’s water abstraction must meet the projected growth in municipal and irrigation demand by the end of 2030 in order to achieve the country’s industrial and economic development plan. The Masinga dam, on the Tana River, is the key to meeting this goal to satisfy the growing demands whilst also continuing to provide hydroelectric power generation. This study quantitatively assesses the reliability and robustness of the Masinga dam system under uncertain future supply and demand using probabilistic climate and population projections, and examines how long-term planning may improve the longevity of the dam. River flow and demand projections are used alongside each other as inputs to the dam system simulation model linked to an optimisation engine to maximise water availability. Water availability after demand satisfaction is assessed for future years, and the projected reliability of the system is calculated for selected years. The analysis shows that maximising power generation on a short-term year-by-year basis achieves 80%, 50% and 1% reliability by 2020, 2025 and 2030 onwards, respectively. Longer term optimal planning, however, has increased system reliability to up to 95% in 2020, 80% in 2025, and more than 40% in 2030 onwards. In addition, increasing the capacity of the reservoir by around 25% can significantly improve the robustness of the system for all future time periods. This study provides a platform for analysing the implication of different planning and management of Masinga dam and suggests that careful consideration should be given to account for growing municipal needs and irrigation schemes in both the immediate and the associated Tana River basin.

  19. Reliability of genetic networks is evolvable

    Braunewell, Stefan; Bornholdt, Stefan


    Control of the living cell functions with remarkable reliability despite the stochastic nature of the underlying molecular networks—a property presumably optimized by biological evolution. We ask here to what extent the ability of a stochastic dynamical network to produce reliable dynamics is an evolvable trait. Using an evolutionary algorithm based on a deterministic selection criterion for the reliability of dynamical attractors, we evolve networks of noisy discrete threshold nodes. We find that, starting from any random network, reliability of the attractor landscape can often be achieved with only a few small changes to the network structure. Further, the evolvability of networks toward reliable dynamics while retaining their function is investigated and a high success rate is found.

  20. Reliability Sensitivity Analysis for Location Scale Family

    洪东跑; 张海瑞


    Many products always operate under various complex environment conditions. To describe the dynamic influence of environment factors on their reliability, a method of reliability sensitivity analysis is proposed. In this method, the location parameter is assumed as a function of relevant environment variables while the scale parameter is assumed as an un- known positive constant. Then, the location parameter function is constructed by using the method of radial basis function. Using the varied environment test data, the log-likelihood function is transformed to a generalized linear expression by de- scribing the indicator as Poisson variable. With the generalized linear model, the maximum likelihood estimations of the model coefficients are obtained. With the reliability model, the reliability sensitivity is obtained. An instance analysis shows that the method is feasible to analyze the dynamic variety characters of reliability along with environment factors and is straightforward for engineering application.

  1. On industrial application of structural reliability theory

    Thoft-Christensen, P


    In this paper it is shown that modern structural reliability theory is being successfully applied to a number of different industries. This review of papers is in no way complete. In the literature there is a large number of similar applications and also application not touched on in this presentation. There has been some concern among scientists from this area that structural reliability theory is not being used by industry. It is probably correct that structural reliability theory is not being used by industry as much as it should be used. However, the work by the ESReDA Working Group clearly shows the vary wide application of structural reliability theory by many different industries. One must also have in mind that industry often is reluctant to publish data related to safety and reliability. (au) 32 refs.

  2. Introduction to quality and reliability engineering

    Jiang, Renyan


    This book presents the state-of-the-art in quality and reliability engineering from a product life cycle standpoint. Topics in reliability include reliability models, life data analysis and modeling, design for reliability and accelerated life testing, while topics in quality include design for quality, acceptance sampling and supplier selection, statistical process control, production tests such as screening and burn-in, warranty and maintenance. The book provides comprehensive insights into two closely related subjects, and includes a wealth of examples and problems to enhance reader comprehension and link theory and practice. All numerical examples can be easily solved using Microsoft Excel. The book is intended for senior undergraduate and post-graduate students in related engineering and management programs such as mechanical engineering, manufacturing engineering, industrial engineering and engineering management programs, as well as for researchers and engineers in the quality and reliability fields. D...

  3. Reliability-Centric High-Level Synthesis

    Tosun, S; Arvas, E; Kandemir, M; Xie, Yuan


    Importance of addressing soft errors in both safety critical applications and commercial consumer products is increasing, mainly due to ever shrinking geometries, higher-density circuits, and employment of power-saving techniques such as voltage scaling and component shut-down. As a result, it is becoming necessary to treat reliability as a first-class citizen in system design. In particular, reliability decisions taken early in system design can have significant benefits in terms of design quality. Motivated by this observation, this paper presents a reliability-centric high-level synthesis approach that addresses the soft error problem. The proposed approach tries to maximize reliability of the design while observing the bounds on area and performance, and makes use of our reliability characterization of hardware components such as adders and multipliers. We implemented the proposed approach, performed experiments with several designs, and compared the results with those obtained by a prior proposal.

  4. Quality and reliability management and its applications


    Integrating development processes, policies, and reliability predictions from the beginning of the product development lifecycle to ensure high levels of product performance and safety, this book helps companies overcome the challenges posed by increasingly complex systems in today’s competitive marketplace.   Examining both research on and practical aspects of product quality and reliability management with an emphasis on applications, the book features contributions written by active researchers and/or experienced practitioners in the field, so as to effectively bridge the gap between theory and practice and address new research challenges in reliability and quality management in practice.    Postgraduates, researchers and practitioners in the areas of reliability engineering and management, amongst others, will find the book to offer a state-of-the-art survey of quality and reliability management and practices.

  5. D5.3 Reading reliability report

    Cetin, Bilge Kartal; Galiotto, Carlo; Cetin, Kamil


    This deliverable presents a detailed description of the main causes of reading reliability degradation. Two main groups of impairments are recognized: those at the physical layer (e.g., fading, multipath, electromagnetic interference, shadowing due to obstacles, tag orientation misalignment, tag...... bending, metallic environments, etc.) and those at the medium access control sub-layer (e.g., collisions due to tag-to-tag, reader-to-reader and multiple readers-to-tag interference). The review presented in this deliverable covers previous reliability reports and existing definitions of RFID reading...... reliability. Performance metrics and methodologies for assessing reading reliability are further discussed. This document also presents a review of state-of-the-art RFID reading reliability improvement schemes. The solutions are classified into physical- (PHY), medium access control- (MAC), upper-, and cross...

  6. Software reliability experiments data analysis and investigation

    Walker, J. Leslie; Caglayan, Alper K.


    The objectives are to investigate the fundamental reasons which cause independently developed software programs to fail dependently, and to examine fault tolerant software structures which maximize reliability gain in the presence of such dependent failure behavior. The authors used 20 redundant programs from a software reliability experiment to analyze the software errors causing coincident failures, to compare the reliability of N-version and recovery block structures composed of these programs, and to examine the impact of diversity on software reliability using subpopulations of these programs. The results indicate that both conceptually related and unrelated errors can cause coincident failures and that recovery block structures offer more reliability gain than N-version structures if acceptance checks that fail independently from the software components are available. The authors present a theory of general program checkers that have potential application for acceptance tests.

  7. 78 FR 21879 - Improving 9-1-1 Reliability; Reliability and Continuity of Communications Networks, Including...


    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Chapter I Improving 9-1-1 Reliability; Reliability and Continuity of Communications Networks, Including Broadband Technologies AGENCY: Federal Communications Commission. ACTION: Notice...

  8. Software Reliability Cases: The Bridge Between Hardware, Software and System Safety and Reliability

    Herrmann, D.S.; Peercy, D.E.


    High integrity/high consequence systems must be safe and reliable; hence it is only logical that both software safety and software reliability cases should be developed. Risk assessments in safety cases evaluate the severity of the consequences of a hazard and the likelihood of it occurring. The likelihood is directly related to system and software reliability predictions. Software reliability cases, as promoted by SAE JA 1002 and 1003, provide a practical approach to bridge the gap between hardware reliability, software reliability, and system safety and reliability by using a common methodology and information structure. They also facilitate early insight into whether or not a project is on track for meeting stated safety and reliability goals, while facilitating an informed assessment by regulatory and/or contractual authorities.

  9. Hurst exponents for short time series

    Qi, Jingchao; Yang, Huijie


    A concept called balanced estimator of diffusion entropy is proposed to detect quantitatively scalings in short time series. The effectiveness is verified by detecting successfully scaling properties for a large number of artificial fractional Brownian motions. Calculations show that this method can give reliable scalings for short time series with length ˜102. It is also used to detect scalings in the Shanghai Stock Index, five stock catalogs, and a total of 134 stocks collected from the Shanghai Stock Exchange Market. The scaling exponent for each catalog is significantly larger compared with that for the stocks included in the catalog. Selecting a window with size 650, the evolution of scaling for the Shanghai Stock Index is obtained by the window's sliding along the series. Global patterns in the evolutionary process are captured from the smoothed evolutionary curve. By comparing the patterns with the important event list in the history of the considered stock market, the evolution of scaling is matched with the stock index series. We can find that the important events fit very well with global transitions of the scaling behaviors.

  10. Study of Movement Reliability for Hoisting Jack under a Rocket Launcher Vehicle%Study of Movement Reliability for Hoisting Jack under a Rocket Launcher Vehicle

    LI Ye-nong; PENG Shu-hua; ZHANG Li-ping; SHI Zhu-kang


    The transmission mechanism of a jack is required to support the combat vehicle reliably within a very short time. So reliability research is very important because the mechanism completes motions required under the conditions within limited time. If the transmission mechanism of the jack supports the rocket launcher steadily, it needs to go through several stages as follows : unlocking, starting, operating, braking, stopping, fixing position and locking. The transmission mechanism of the jack is a complicated and single degree of freedom mechanical system; it can be considered an imaginary mechanical model that has an equivalent moment of inertia and equivalent torque. According to the characteristics of each supporting stages, dynamics equations of the mechanism are established. At the stages of starting and operating, a driving moment and resistance moment are dealt with for a Normal distribution. The design principles for movement reliability of completing action are established and the design principles for time reliability of completing action within a limited time are established. Finally, movement reliability of the transmission mechanism of the jack is 0. 9 852, according to our calculation. Reliability of time to complete action is 0. 9 943.

  11. Scaled CMOS Technology Reliability Users Guide

    White, Mark


    The desire to assess the reliability of emerging scaled microelectronics technologies through faster reliability trials and more accurate acceleration models is the precursor for further research and experimentation in this relevant field. The effect of semiconductor scaling on microelectronics product reliability is an important aspect to the high reliability application user. From the perspective of a customer or user, who in many cases must deal with very limited, if any, manufacturer's reliability data to assess the product for a highly-reliable application, product-level testing is critical in the characterization and reliability assessment of advanced nanometer semiconductor scaling effects on microelectronics reliability. A methodology on how to accomplish this and techniques for deriving the expected product-level reliability on commercial memory products are provided.Competing mechanism theory and the multiple failure mechanism model are applied to the experimental results of scaled SDRAM products. Accelerated stress testing at multiple conditions is applied at the product level of several scaled memory products to assess the performance degradation and product reliability. Acceleration models are derived for each case. For several scaled SDRAM products, retention time degradation is studied and two distinct soft error populations are observed with each technology generation: early breakdown, characterized by randomly distributed weak bits with Weibull slope (beta)=1, and a main population breakdown with an increasing failure rate. Retention time soft error rates are calculated and a multiple failure mechanism acceleration model with parameters is derived for each technology. Defect densities are calculated and reflect a decreasing trend in the percentage of random defective bits for each successive product generation. A normalized soft error failure rate of the memory data retention time in FIT/Gb and FIT/cm2 for several scaled SDRAM generations is

  12. 78 FR 38851 - Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards


    ... coordinator on an annual basis. Facilities Design, Connections, and Maintenance Reliability Standards 41. FAC... Federal Energy Regulatory Commission 18 CFR Part 40 Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards AGENCY: Federal Energy Regulatory Commission, DOE. ACTION: Notice of...

  13. 75 FR 71613 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits


    ... Reliability Operating Limits November 18, 2010. AGENCY: Federal Energy Regulatory Commission. ACTION: Notice... Interconnection Reliability Operating Limits. The Commission also proposes to approve the addition of two new.... Mandatory Reliability Standards 3 B. Order No. 693 Directives 4 II. Discussion 7 A. System Operating...

  14. High reliable internet hosting : a case study of handling unanticipated threats to reliability

    Wijnhoven, A.B.J.M.; Ehrenhard, M.L.; Alink, T.


    Internet hosting is pivotal for reliable access to internet resources. Yet, little research has been done on what threatens a hosting service’s reliability. Our analysis of reliability threatening incidents results in four causes of unreliability: the service’s technical architecture, service employ

  15. Component Reliability Assessment of Offshore Jacket Platforms

    V.J. Kurian


    Full Text Available Oil and gas industry is one of the most important industries contributing to the Malaysian economy. To extract hydrocarbons, various types of production platforms have been developed. Fixed jacket platform is the earliest type of production structure, widely installed in Malaysia’s shallow and intermediate waters. To date, more than 60% of these jacket platforms have operated exceeding their initial design life, thus making the re-evaluation and reassessment necessary for these platforms to continue to be put in service. In normal engineering practice, system reliability of a structure is evaluated as its safety parameter. This method is however, much complicated and time consuming. Assessing component's reliability can be an alternative approach to provide assurance about a structure’s condition in an early stage. Design codes such as the Working Stress Design (WSD and the Load and Resistance Factor Design (LRFD are well established for the component-level assessment. In reliability analysis, failure function, which consists of strength and load, is used to define the failure event. If the load acting exceeds the capacity of a structure, the structure will fail. Calculation of stress utilization ratio as given in the design codes is able to predict the reliability of a member and to estimate the extent to which a member is being utilised. The basic idea of this ratio is that if it is more than one, the member has failed and vice versa. Stress utilization ratio is a ratio of applied stress, which is the output reaction of environmental loadings acting on the structural member, to the design strength that comes from the member’s geometric and material properties. Adopting this ratio as the failure event, the reliability of each component is found. This study reviews and discusses the reliability for selected members of three Malaysian offshore jacket platforms. First Order Reliability Method (FORM was used to generate reliability index and

  16. Short-circuit impedance measurement

    Pedersen, Knud Ole Helgesen; Nielsen, Arne Hejde; Poulsen, Niels Kjølstad


    Methods for estimating the short-circuit impedance in the power grid are investigated for various voltage levels and situations. The short-circuit impedance is measured, preferably from naturally occurring load changes in the grid, and it is shown that such a measurement system faces different...

  17. Short implants in oral rehabilitation

    Emmanuel Panobianco Chizolini


    Full Text Available Introduction and objective: The placement of short dental implants is used as an alternative treatment modality to bone grafting procedures. The aim of this study was to discuss, through a literature review, the features, indications and biomechanical aspects of short implants, as well as to report the clinical factors that influence on their indication. Literature review and conclusion: It was found that short implants osseointegration can be compromised by risk factors that must be controlled to achieve treatment success. In conclusion, the main indication of short implants is to avoid an invasive surgery at atrophic areas of maxilla and mandible. Furthermore, implant design associated with surface treatment are factors that compensate its short length.

  18. Production of Reliable Flight Crucial Software: Validation Methods Research for Fault Tolerant Avionics and Control Systems Sub-Working Group Meeting

    Dunham, J. R. (Editor); Knight, J. C. (Editor)


    The state of the art in the production of crucial software for flight control applications was addressed. The association between reliability metrics and software is considered. Thirteen software development projects are discussed. A short term need for research in the areas of tool development and software fault tolerance was indicated. For the long term, research in format verification or proof methods was recommended. Formal specification and software reliability modeling, were recommended as topics for both short and long term research.

  19. a Reliability Evaluation System of Association Rules

    Chen, Jiangping; Feng, Wanshu; Luo, Minghai


    In mining association rules, the evaluation of the rules is a highly important work because it directly affects the usability and applicability of the output results of mining. In this paper, the concept of reliability was imported into the association rule evaluation. The reliability of association rules was defined as the accordance degree that reflects the rules of the mining data set. Such degree contains three levels of measurement, namely, accuracy, completeness, and consistency of rules. To show its effectiveness, the "accuracy-completeness-consistency" reliability evaluation system was applied to two extremely different data sets, namely, a basket simulation data set and a multi-source lightning data fusion. Results show that the reliability evaluation system works well in both simulation data set and the actual problem. The three-dimensional reliability evaluation can effectively detect the useless rules to be screened out and add the missing rules thereby improving the reliability of mining results. Furthermore, the proposed reliability evaluation system is applicable to many research fields; using the system in the analysis can facilitate obtainment of more accurate, complete, and consistent association rules.

  20. Reliability design method for steam turbine blades

    Jinyuan SHI


    Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliabil-ity design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical cal-culation of test data. The fatigue strength and the vibra-tion design reliability of turbine blades are determined with the aid of a probabilistic design method and by inter-ference models for stress distribution and strength distri-bution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades.

  1. Study on segmented distribution for reliability evaluation

    Huaiyuan Li


    Full Text Available In practice, the failure rate of most equipment exhibits different tendencies at different stages and even its failure rate curve behaves a multimodal trace during its life cycle. As a result, traditionally evaluating the reliability of equipment with a single model may lead to severer errors. However, if lifetime is divided into several different intervals according to the characteristics of its failure rate, piecewise fitting can more accurately approximate the failure rate of equipment. Therefore, in this paper, failure rate is regarded as a piecewise function, and two kinds of segmented distribution are put forward to evaluate reliability. In order to estimate parameters in the segmented reliability function, Bayesian estimation and maximum likelihood estimation (MLE of the segmented distribution are discussed in this paper. Since traditional information criterion is not suitable for the segmented distribution, an improved information criterion is proposed to test and evaluate the segmented reliability model in this paper. After a great deal of testing and verification, the segmented reliability model and its estimation methods presented in this paper are proven more efficient and accurate than the traditional non-segmented single model, especially when the change of the failure rate is time-phased or multimodal. The significant performance of the segmented reliability model in evaluating reliability of proximity sensors of leading-edge flap in civil aircraft indicates that the segmented distribution and its estimation method in this paper could be useful and accurate.

  2. Reliability characteristics and applicability of a repeated sprint ability test in male young soccer players.

    Castagna, Carlo; Francini, Lorenzo; Krustrup, Peter; Fenarnandes-da-Silva, Juliano; Póvoas, Susana C A; Bernardini, Andrea; D'Ottavio, Stefano


    The aim of this study was to examine the usefulness and reliability characteristics of a repeated sprint ability test considering 5 line sprints of 30-m interspersed with 30-s of active recovery in non-elite outfield young male soccer players. Twenty-six (age 14.9±1.2 years, height 1.72±0.12 cm, body mass 62.2±5.1 kg) players were tested 48 hours and 7 days apart for 5x30-m performance over 5 trials (T1-T5). Short- (T1-T2) and long-term reliability (T1-T3-T4-T5) were assessed with Intraclass Correlation Coefficient (ICC) and with typical error for measurement (TEM). Short- and long-term reliability ICCs and TEMs for total sprint time and best sprint performance were nearly perfect and satisfactory, respectively. Usefulness (as smallest worthwhile change and TEM ratio) resulted acceptable (i.e =1) and good (i.e >1) for total sprint time and best sprint performance, respectively. The present study revealed that the 5x30-m sprint test is a reliable field test in the short and long-term when the sum of sprint times and the best sprint performance are considered as outcome variables. Sprint performance decrements variables showed large variability across trials.

  3. MEMS reliability: The challenge and the promise

    Miller, W.M.; Tanner, D.M.; Miller, S.L.; Peterson, K.A.


    MicroElectroMechanical Systems (MEMS) that think, sense, act and communicate will open up a broad new array of cost effective solutions only if they prove to be sufficiently reliable. A valid reliability assessment of MEMS has three prerequisites: (1) statistical significance; (2) a technique for accelerating fundamental failure mechanisms, and (3) valid physical models to allow prediction of failures during actual use. These already exist for the microelectronics portion of such integrated systems. The challenge lies in the less well understood micromachine portions and its synergistic effects with microelectronics. This paper presents a methodology addressing these prerequisites and a description of the underlying physics of reliability for micromachines.

  4. Reliability Assessment of Wave Energy Devices

    Ambühl, Simon; Kramer, Morten; Kofoed, Jens Peter;


    This paper focuses on reliability assessment of Wave Energy Device (WED) substructures with respect to fatigue loading. Failure due to fatigue is an important failure mode of most offshore structures. The focus of the fatigue reliability assessment is in this paper on welded details in steel...... substructures. The methodology is illustrated using the Wavestar prototype located at Hanstholm (DK) as a case study. The stochastic model presented can be used for reliability assessment and for calibration of Fatigue Design Factors (FDF) of wave power plant substructures. The fatigue life is modeled using...


    Popescu V.S.


    Full Text Available Power distribution systems are basic parts of power systems and reliability of these systems at present is a key issue for power engineering development and requires special attention. Operation of distribution systems is accompanied by a number of factors that produce random data a large number of unplanned interruptions. Research has shown that the predominant factors that have a significant influence on the reliability of distribution systems are: weather conditions (39.7%, defects in equipment(25% and unknown random factors (20.1%. In the article is studied the influence of random behavior and are presented estimations of reliability of predominantly rural electrical distribution systems.

  6. When and why are reliable organizations favored?

    Ethiraj, Sendil; Yi, Sangyoon

    in this assertion. Principally, we show that whether reliable organizations are favored depends on the nature of the environment. When environments are complex, reliability is selected out. In more complex environments, variability is more valued by selection forces. Further, we also examine the consequences......In the 1980s, organization theory witnessed a decade long debate about the incentives and consequences of organizational change. Though the fountainhead of this debate was the observation that reliable organizations are the “consequence” rather than the “cause” of selection forces, much...

  7. Specification for reliability data management system



    This document contains the objectives, scopes, a brief delineation of the design, performance, and definition of the Reliability Data Management System (RDMS). The General Electric Company - Fast Breeder Reactor Department (GE-FBRD) has responsibility for the design and implementation of a Reliability Data Management System (RDMS). This document describes and specifies the RDMS requirements. The RDMS is currently focused on obtaining data for the Clinch River Breeder Reactor Plant (CRBRP) Shutdown System and Shutdown Heat Removal System, but has been designed with capability and flexibility for accommodating additional CRBRP and Liquid Metal Fast Breeder Reactor (LMFBR) reliability data.

  8. Challenges Regarding IP Core Functional Reliability

    Berg, Melanie D.; LaBel, Kenneth A.


    For many years, intellectual property (IP) cores have been incorporated into field programmable gate array (FPGA) and application specific integrated circuit (ASIC) design flows. However, the usage of large complex IP cores were limited within products that required a high level of reliability. This is no longer the case. IP core insertion has become mainstream including their use in highly reliable products. Due to limited visibility and control, challenges exist when using IP cores and subsequently compromise product reliability. We discuss challenges and suggest potential solutions to critical application IP insertion.

  9. Computer system reliability safety and usability

    Dhillon, BS


    Computer systems have become an important element of the world economy, with billions of dollars spent each year on development, manufacture, operation, and maintenance. Combining coverage of computer system reliability, safety, usability, and other related topics into a single volume, Computer System Reliability: Safety and Usability eliminates the need to consult many different and diverse sources in the hunt for the information required to design better computer systems.After presenting introductory aspects of computer system reliability such as safety, usability-related facts and figures,

  10. Measurement Practices for Reliability and Power Quality

    Kueck, JD


    This report provides a distribution reliability measurement ''toolkit'' that is intended to be an asset to regulators, utilities and power users. The metrics and standards discussed range from simple reliability, to power quality, to the new blend of reliability and power quality analysis that is now developing. This report was sponsored by the Office of Electric Transmission and Distribution, U.S. Department of Energy (DOE). Inconsistencies presently exist in commonly agreed-upon practices for measuring the reliability of the distribution systems. However, efforts are being made by a number of organizations to develop solutions. In addition, there is growing interest in methods or standards for measuring power quality, and in defining power quality levels that are acceptable to various industries or user groups. The problems and solutions vary widely among geographic areas and among large investor-owned utilities, rural cooperatives, and municipal utilities; but there is still a great degree of commonality. Industry organizations such as the National Rural Electric Cooperative Association (NRECA), the Electric Power Research Institute (EPRI), the American Public Power Association (APPA), and the Institute of Electrical and Electronics Engineers (IEEE) have made tremendous strides in preparing self-assessment templates, optimization guides, diagnostic techniques, and better definitions of reliability and power quality measures. In addition, public utility commissions have developed codes and methods for assessing performance that consider local needs. There is considerable overlap among these various organizations, and we see real opportunity and value in sharing these methods, guides, and standards in this report. This report provides a ''toolkit'' containing synopses of noteworthy reliability measurement practices. The toolkit has been developed to address the interests of three groups: electric power users, utilities, and

  11. A reliability measure of protein-protein interactions and a reliability measure-based search engine.

    Park, Byungkyu; Han, Kyungsook


    Many methods developed for estimating the reliability of protein-protein interactions are based on the topology of protein-protein interaction networks. This paper describes a new reliability measure for protein-protein interactions, which does not rely on the topology of protein interaction networks, but expresses biological information on functional roles, sub-cellular localisations and protein classes as a scoring schema. The new measure is useful for filtering many spurious interactions, as well as for estimating the reliability of protein interaction data. In particular, the reliability measure can be used to search protein-protein interactions with the desired reliability in databases. The reliability-based search engine is available at We believe this is the first search engine for interacting proteins, which is made available to public. The search engine and the reliability measure of protein interactions should provide useful information for determining proteins to focus on.

  12. The Turkish Adaptation of the Burnout Measure-Short Version (BMS) and Couple Burnout Measure-Short Version (CBMS) and the Relationship between Career and Couple Burnout Based on Psychoanalytic-Existential Perspective

    Capri, Burhan


    The purpose of this research is to carry out the Turkish adaptation, validity, and reliability studies of Burnout Measure-Short Form (BMS) and Couple Burnout Measure-Short Form (CBMS) and also to analyze the correlation between the careers and couple burnout scores of the participants from the psychoanalytic-existential perspective. This research…

  13. Intra- and inter-rater reliability of the Sollerman hand function test in patients with chronic stroke

    Brogårdh, Christina; Persson, Ann L; Sjölund, Bengt H


    PURPOSE: To examine whether the Sollerman hand function test is reliable in a test-retest situation in patients with chronic stroke. METHOD: Three independent examiners observed each patient at three experimental sessions; two days in week 1 (short-term test-retest) and one day in week 4 (long...... hand function test seems to be a reliable test in patients with chronic stroke, but we recommend that the same examiner evaluates a patient's hand function pre- and post-treatment....

  14. Space Mission Human Reliability Analysis (HRA) Project

    National Aeronautics and Space Administration — The purpose of this project is to extend current ground-based Human Reliability Analysis (HRA) techniques to a long-duration, space-based tool to more effectively...

  15. MOV reliability evaluation and periodic verification scheduling

    Bunte, B.D.


    The purpose of this paper is to establish a periodic verification testing schedule based on the expected long term reliability of gate or globe motor operated valves (MOVs). The methodology in this position paper determines the nominal (best estimate) design margin for any MOV based on the best available information pertaining to the MOVs design requirements, design parameters, existing hardware design, and present setup. The uncertainty in this margin is then determined using statistical means. By comparing the nominal margin to the uncertainty, the reliability of the MOV is estimated. The methodology is appropriate for evaluating the reliability of MOVs in the GL 89-10 program. It may be used following periodic testing to evaluate and trend MOV performance and reliability. It may also be used to evaluate the impact of proposed modifications and maintenance activities such as packing adjustments. In addition, it may be used to assess the impact of new information of a generic nature which impacts safety related MOVs.

  16. Boolean networks with robust and reliable trajectories

    Schmal, Christoph; Peixoto, Tiago P; Drossel, Barbara, E-mail: schmal@physik.uni-bielefeld.d, E-mail: tiago@fkp.tu-darmstadt.d, E-mail: drossel@fkp.tu-darmstadt.d [Institut fuer Festkoerperphysik, TU Darmstadt, Hochschulstrasse 6, 64289 Darmstadt (Germany)


    We construct and investigate Boolean networks that follow a given reliable trajectory in state space, which is insensitive to fluctuations in the updating schedule and which is also robust against noise. Robustness is quantified as the probability that the dynamics return to the reliable trajectory after a perturbation of the state of a single node. In order to achieve high robustness, we navigate through the space of possible update functions by using an evolutionary algorithm. We constrain the networks to those having the minimum number of connections required to obtain the reliable trajectory. Surprisingly, we find that robustness always reaches values close to 100% during the evolutionary optimization process. The set of update functions can be evolved such that it differs only slightly from that of networks that were not optimized with respect to robustness. The state space of the optimized networks is dominated by the basin of attraction of the reliable trajectory.

  17. Solder joint technology materials, properties, and reliability

    Tu, King-Ning


    Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

  18. Infants prefer to imitate a reliable person.

    Poulin-Dubois, Diane; Brooker, Ivy; Polonia, Alexandra


    Research has shown that preschoolers prefer to learn from individuals who are a reliable source of information. The current study examined whether the past reliability of a person's emotional signals influences infants' willingness to imitate that person. An emotional referencing task was first administered to infants in order to demonstrate the experimenter's credibility or lack thereof. Next, infants in both conditions watched as the same experimenter turned on a touch light using her forehead. Infants were then given the opportunity to reproduce this novel action. As expected, infants in the unreliable condition developed the expectation that the person's emotional cues were misleading. Thus, these infants were subsequently more likely to use their hands than their foreheads when attempting to turn on the light. In contrast, infants in the reliable group were more likely to imitate the experimenter's action using their foreheads. These results suggest that the reliability of the model influences infants' imitation.

  19. Reliability of lightning resistant overhead distribution lines

    Tolbert, L.M.; Cleveland, J.T.; Degenhardt, L.J.


    An assessment of the 32 year historical reliability of the 13.8 kV electrical distribution system at the Oak Ridge National Laboratory (ORNL) in Tennessee has yielded several conclusions useful In the planning of Industrial power Systems. The system configuration at ORNL has essentially remained unchanged in the last 32 years which allows a meaningful comparison of reliability trends for the plant`s eight overhead distribution lines, two of which were built in the 1960`s with lightning resistant construction techniques. Meticulous records indicating the cause, duration, and location of 135 electric outages in the plant`s distribution system have allowed a reliability assessment to be performed. The assessment clearly shows how differences in voltage construction class, length, age, and maximum elevation above a reference elevation influence the reliability of overhead power distribution lines. Comparisons are also made between the ORNL historical data and predicted failure rates from ANSI and IEEE industry surveys.

  20. Flight control electronics reliability/maintenance study

    Dade, W. W.; Edwards, R. H.; Katt, G. T.; Mcclellan, K. L.; Shomber, H. A.


    Collection and analysis of data are reported that concern the reliability and maintenance experience of flight control system electronics currently in use on passenger carrying jet aircraft. Two airlines B-747 airplane fleets were analyzed to assess the component reliability, system functional reliability, and achieved availability of the CAT II configuration flight control system. Also assessed were the costs generated by this system in the categories of spare equipment, schedule irregularity, and line and shop maintenance. The results indicate that although there is a marked difference in the geographic location and route pattern between the airlines studied, there is a close similarity in the reliability and the maintenance costs associated with the flight control electronics.

  1. Design for Reliability of Power Electronic Systems

    Wang, Huai; Ma, Ke; Blaabjerg, Frede


    availability, long lifetime, sufficient robustness, low maintenance cost and low cost of energy. However, the reliability predictions are still dominantly according to outdated models and terms, such as MIL-HDBK-217F handbook models, Mean-Time-To-Failure (MTTF), and Mean-Time-Between-Failures (MTBF......Advances in power electronics enable efficient and flexible processing of electric power in the application of renewable energy sources, electric vehicles, adjustable-speed drives, etc. More and more efforts are devoted to better power electronic systems in terms of reliability to ensure high......). A collection of methodologies based on Physics-of-Failure (PoF) approach and mission profile analysis are presented in this paper to perform reliability-oriented design of power electronic systems. The corresponding design procedures and reliability prediction models are provided. Further on, a case study...

  2. Operational reliability of standby safety systems

    Grant, G.M.; Atwood, C.L.; Gentillon, C.D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others


    The Idaho National Engineering Laboratory (INEL) is evaluating the operational reliability of several risk-significant standby safety systems based on the operating experience at US commercial nuclear power plants from 1987 through 1993. The reliability assessed is the probability that the system will perform its Probabilistic Risk Assessment (PRA) defined safety function. The quantitative estimates of system reliability are expected to be useful in risk-based regulation. This paper is an overview of the analysis methods and the results of the high pressure coolant injection (HPCI) system reliability study. Key characteristics include (1) descriptions of the data collection and analysis methods, (2) the statistical methods employed to estimate operational unreliability, (3) a description of how the operational unreliability estimates were compared with typical PRA results, both overall and for each dominant failure mode, and (4) a summary of results of the study.

  3. Reliability of microtechnology interconnects, devices and systems

    Liu, Johan; Sarkka, Jussi; Tegehall, Per-Erik; Andersson, Cristina


    This text discusses the reliability of microtechnology products from the bottom up, beginning with devices and extending to systems. It covers many topics, and it addresses specific failure modes in solder and conductive adhesives at great length.

  4. Software architecture and design for reliability predictability

    Semegn, Assefa D


    Reliability prediction of a software product is complex due to interdependence and interactions among components and the difficulty of representing this behavior with tractable models. Models developed by making simplifying assumptions about the software

  5. Reliability Issues for Photovoltaic Modules (Presentation)

    Kurtz, S.


    Si modules good in field; new designs need reliability testing. CdTe & CIGS modules sensitive to moisture; carefully seal. CPV in product development stage; benefits from expertise in other industries.

  6. 76 FR 71011 - Reliability Technical Conference Agenda


    ..., President and CEO, Consolidated Edison Inc., on behalf of Consolidated Edison and the Edison Electric..., North American Electric Reliability Corporation Thomas J. Galloway, President and Chief Executive... Monroe, Executive Vice President and Chief Operating Officer, Southwest Power Pool (SPP) Thomas...


    A. Stepanov


    Full Text Available The ways of increasing of exploitation reliability of dump trucks with the aim of increasing of effectiveness of exploitation of transportation systems of rock heaps at coal mines.

  8. Reliability of chemical analyses of water samples

    Beardon, R.


    Ground-water quality investigations require reliable chemical analyses of water samples. Unfortunately, laboratory analytical results are often unreliable. The Uranium Mill Tailings Remedial Action (UMTRA) Project`s solution to this problem was to establish a two phase quality assurance program for the analysis of water samples. In the first phase, eight laboratories analyzed three solutions of known composition. The analytical accuracy of each laboratory was ranked and three laboratories were awarded contracts. The second phase consists of on-going monitoring of the reliability of the selected laboratories. The following conclusions are based on two years experience with the UMTRA Project`s Quality Assurance Program. The reliability of laboratory analyses should not be taken for granted. Analytical reliability may be independent of the prices charged by laboratories. Quality assurance programs benefit both the customer and the laboratory.

  9. High Reliability Oscillators for Terahertz Systems Project

    National Aeronautics and Space Administration — To develop reliable THz sources with high power and high DC-RF efficiency, Virginia Diodes, Inc. will develop a thorough understanding of the complex interactions...


    Wang Qiang; Lu Yang; Xu Zijun; Han Jianghong


    With the rapid progress of component technology,the software development methodology of gathering a large number of components for designing complex software systems has matured.But,how to assess the application reliability accurately with the information of system architecture and the components reliabilities together has become a knotty problem.In this paper,the defects in formal description of software architecture and the limitations in existed model assumptions are both analyzed.Moreover,a new software reliability model called Component Interaction Mode (CIM) is proposed.With this model,the problem for existed component-based software reliability analysis models that cannot deal with the cases of component interaction with non-failure independent and non-random control transition is resolved.At last,the practice examples are presented to illustrate the effectiveness of this model

  11. Reliability of chemical analyses of water samples

    Beardon, R.


    Ground-water quality investigations require reliable chemical analyses of water samples. Unfortunately, laboratory analytical results are often unreliable. The Uranium Mill Tailings Remedial Action (UMTRA) Project`s solution to this problem was to establish a two phase quality assurance program for the analysis of water samples. In the first phase, eight laboratories analyzed three solutions of known composition. The analytical accuracy of each laboratory was ranked and three laboratories were awarded contracts. The second phase consists of on-going monitoring of the reliability of the selected laboratories. The following conclusions are based on two years experience with the UMTRA Project`s Quality Assurance Program. The reliability of laboratory analyses should not be taken for granted. Analytical reliability may be independent of the prices charged by laboratories. Quality assurance programs benefit both the customer and the laboratory.

  12. On the reliability of Seasonal Climate Forecasts

    Weisheimer, Antje


    Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: How good are seasonal climate forecasts on a scale of 1-5 (where 5 is very good), and how good can we expect them to be in 30 years time? Seasonal climate forecasts are made from ensembles of integrations of numerical models of climate. We argue that goodness should be assessed primarily in terms of the probabilistic reliability of these ensemble-based forecasts and that a 5 should be reserved for systems which are not only reliable overall, but where, in particular, small ensemble spread is a reliable indicator of low ensemble forecast error. We study the reliability of regional temperature and precipitation forecasts of the current operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts, universally regarded as a world leading operational institute producing seasonal climate forecasts. A wide range of goodness rankings, depending on regio...

  13. CSP Assembly Reliability: Commercial and Harsh Environments

    Ghaffarian, R.; Kim, N.; Selk, K.; Bjorndahl, B.; Bonner, J.; Barr, S.


    The JPL-led CSP Consortium of enterprises representing government agencies and private companies has jointed together to pool in-kind resources for developing the quality and reliability of chip scale packages (CSPs) for a variety of projects.


    Monica BALDEA


    Full Text Available The reliability defined through probability, reflects the measurement of the product's quality depending on time. We use the probability parameters as aleatory variables, the density functions of probability, the distribution functions

  15. Reliability of power electronic converter systems

    Chung, Henry Shu-hung; Blaabjerg, Frede; Pecht, Michael


    This book outlines current research into the scientific modeling, experimentation, and remedial measures for advancing the reliability, availability, system robustness, and maintainability of Power Electronic Converter Systems (PECS) at different levels of complexity.

  16. Optimal, Reliability-Based Code Calibration

    Sørensen, John Dalsgaard


    acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for the ultimate and the serviceability limit states. Finally the paper describes a procedure for the practical implementation...

  17. The reliable multicast protocol application programming interface

    Montgomery , Todd; Whetten, Brian


    The Application Programming Interface for the Berkeley/WVU implementation of the Reliable Multicast Protocol is described. This transport layer protocol is implemented as a user library that applications and software buses link against.

  18. Reliability Engineering for ATLAS Petascale Data Processing on the Grid

    Golubkov, D V; The ATLAS collaboration; Vaniachine, A V


    The ATLAS detector is in its third year of continuous LHC running taking data for physics analysis. A starting point for ATLAS physics analysis is reconstruction of the raw data. First-pass processing takes place shortly after data taking, followed later by reprocessing of the raw data with updated software and calibrations to improve the quality of the reconstructed data for physics analysis. Data reprocessing involves a significant commitment of computing resources and is conducted on the Grid. The reconstruction of one petabyte of ATLAS data with 1B collision events from the LHC takes about three million core-hours. Petascale data processing on the Grid involves millions of data processing jobs. At such scales, the reprocessing must handle a continuous stream of failures. Automatic job resubmission recovers transient failures at the cost of CPU time used by the failed jobs. Orchestrating ATLAS data processing applications to ensure efficient usage of tens of thousands of CPU-cores, reliability engineering ...

  19. Optimized load sharing control by means of thermal reliability management

    Nesgaard, Carsten; Andersen, Michael Andreas E.


    With new applications for high-current low-output voltage power systems emerging nearly every day the need for new and cost-efficient power system designs is a matter of course. As output voltage levels continue to decrease an approach that seems more and more attractive is the implementation...... that each converter in the configuration delivers its share of the total output power. In other words parallel-operation of multiple converters is employed when specifications require a highly reliable system, designable within a very short time frame and at low costs. However, to make full use...... of distributed power configurations with point-of-load power conversion. This technique distributes a high voltage to all parts of the system, thus minimizing the voltage drops throughout the distribution network. However, this configuration only solves the problem of power losses in the distribution network...

  20. Fast Evaluation of the Reliability of Container Securing Arrangements

    Mansour, A.E.; Jensen, Jørgen Juncher; Olsen, Anders Smærup


    In this paper closed form expressions for the transfer functions for the motions and accelerations are used to generate linear transfer functions for forces in lashed and unlashed containers located anywhere in a ship. Long term statistics for these forces are derived by application of a proper...... operational profile and a scatter diagram for the specific route, taking into account the effect of weather routing. Wind forces are added to the wave inertia and gravity loads to determine the limit state equations for evaluating the re-liability of a stack of containers against damage or loss. Several modes...... of container failures are considered including racking and corner post failure. The associated probability of failure is determined using a FORM approach. The procedure can easily be programmed in a simple spreadsheet and the calculation time is very short due to the use of analytical transfer functions...

  1. Note: Reliable low-vibration piezo-mechanical shutter.

    Bauer, Michael; Franzreb, Philipp Pierre; Spethmann, Nicolas; Widera, Artur


    We present a mechanical shutter based on a bending piezo-actuator. The shutter features an active aperture of about 2 mm, allowing for full extinction and lossless transmission of a beam. Acoustic noise and mechanical vibrations produced are very low and the shutter is outstandingly long-lived; a test device has undergone 20 × 10(6) cycles without breaking. A reflector makes the shutter capable of reliably interrupting a beam with at least 2 W of cw power at 780 nm. The shutter is well suited to create pulses as short as 16 ms, while pulse lengths down to 1 ms are possible. The rise and fall times are approximately 120 µs, with a delay of 2 ms. Jitter stays below 10 µs, while long-term drifts stay well below 500 µs.

  2. Space Vehicle Reliability Modeling in DIORAMA

    Tornga, Shawn Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    When modeling system performance of space based detection systems it is important to consider spacecraft reliability. As space vehicles age the components become prone to failure for a variety of reasons such as radiation damage. Additionally, some vehicles may lose the ability to maneuver once they exhaust fuel supplies. Typically failure is divided into two categories: engineering mistakes and technology surprise. This document will report on a method of simulating space vehicle reliability in the DIORAMA framework.

  3. Analysis on Some of Software Reliability Models


    Software reliability & maintainability evaluation tool (SRMET 3.0) is introducted in detail in this paper,which was developed by Software Evaluation and Test Center of China Aerospace Mechanical Corporation. SRMET 3.0is supported by seven soft ware reliability models and four software maintainability models. Numerical characteristicsfor all those models are deeply studied in this paper, and corresponding numerical algorithms for each model are alsogiven in the paper.

  4. Reliability and diagnostic of modular systems

    J. Kohlas


    Full Text Available Reliability and diagnostic are in general two problems discussed separately. Yet the two problems are in fact closely related to each other. Here, this relation is considered in the simple case of modular systems. We show, how the computation of reliability and diagnostic can efficiently be done within the same Bayesian network induced by the modularity of the structure function of the system.

  5. Reliable computer systems design and evaluatuion

    Siewiorek, Daniel


    Enhance your hardware/software reliabilityEnhancement of system reliability has been a major concern of computer users and designers ¦ and this major revision of the 1982 classic meets users' continuing need for practical information on this pressing topic. Included are case studies of reliablesystems from manufacturers such as Tandem, Stratus, IBM, and Digital, as well as coverage of special systems such as the Galileo Orbiter fault protection system and AT&T telephone switching processors.

  6. Offshore wind turbines reliability, availability and maintenance

    Tavner, Peter


    The first book to specifically focus on offshore wind turbine technology and which addresses practically wind turbine reliability and availability. The book draws on the author's experience of power generation reliability and availability and the condition monitoring of that plant to describe the problems facing the developers of offshore wind farms and the solutions available to them to raise availability, reduce cost of energy and improve through life cost.

  7. Telecommunications system reliability engineering theory and practice

    Ayers, Mark L


    "Increasing system complexity require new, more sophisticated tools for system modeling and metric calculation. Bringing the field up to date, this book provides telecommunications engineers with practical tools for analyzing, calculating, and reporting availability, reliability, and maintainability metrics. It gives the background in system reliability theory and covers in-depth applications in fiber optic networks, microwave networks, satellite networks, power systems, and facilities management. Computer programming tools for simulating the approaches presented, using the Matlab software suite, are also provided"

  8. Validity and reliability in qualitative researches


    Abstract   Today science world changes sharply in a high speed. In a way that in all areas such as research methods these changes are obvious. Although concepts such as validity and reliability in Positivist methodology have been used with distinct and general rules, in post positivist period in which they have paid much more attention to qualitative research, these principles have lost their general form. In one hand some thinkers stress on applying common validity and reliability quantitati...

  9. Reliability assessment of continuous mining technological systems


    Article is devoted to the analysis of reliability of parameters of continuous system of extraction with use of various approaches with the purpose of performance of a fast estimation of general efficiency of the equipment of such industrial systems, as Monte-Carlo and stress-force of intervention. Article is devoted to the analysis of reliability of parameters of continuous system of extraction with use of various approaches with the purpose of performance of a fast estimation of general e...

  10. Reliability Analysis of DOOF for Weibull Distribution

    陈文华; 崔杰; 樊小燕; 卢献彪; 相平


    Hierarchical Bayesian method for estimating the failure probability under DOOF by taking the quasi-Beta distribution as the prior distribution is proposed in this paper. The weighted Least Squares Estimate method was used to obtain the formula for computing reliability distribution parameters and estimating the reliability characteristic values under DOOF. Taking one type of aerospace electrical connector as an example, the correctness of the above method through statistical analysis of electrical connector accelerated life test data was verified.

  11. Integrated Methodology for Software Reliability Analysis

    Marian Pompiliu CRISTESCU


    Full Text Available The most used techniques to ensure safety and reliability of the systems are applied together as a whole, and in most cases, the software components are usually overlooked or to little analyzed. The present paper describes the applicability of fault trees analysis software system, analysis defined as Software Fault Tree Analysis (SFTA, fault trees are evaluated using binary decision diagrams, all of these being integrated and used with help from Java library reliability.

  12. Production Facility System Reliability Analysis Report

    Dale, Crystal Buchanan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This document describes the reliability, maintainability, and availability (RMA) modeling of the Los Alamos National Laboratory (LANL) design for the Closed Loop Helium Cooling System (CLHCS) planned for the NorthStar accelerator-based 99Mo production facility. The current analysis incorporates a conceptual helium recovery system, beam diagnostics, and prototype control system into the reliability analysis. The results from the 1000 hr blower test are addressed.

  13. Reliability of Search and Rescue Action

    Burciu, Zbigniew


    Determination of the reliability of Search and Rescue action system allows the SAR Mission Coordinator to increase the effectiveness of the action through the proper selection of operational characteristics of the system elements, in particular the selection of the rescue units and auxiliary units. The paper presents the example of the influence of water temperature and time of the action on the reliability of search and rescue action in the case of rescuing a survivor in the water.

  14. Gearbox Reliability Collaborative (GRC) Description and Loading

    Oyague, F.


    This document describes simulated turbine load cases in accordance to the IEC 61400-1 Ed.3 standard, which is representative of the typical wind turbine design process. The information presented herein is intended to provide a broad understanding of the gearbox reliability collaborative 750kW drivetrain and turbine configuration. In addition, fatigue and ultimate strength drivetrain loads resulting from simulations are presented. This information provides the bases for the analytical work of the gearbox reliability collaborative effort.

  15. Semiconductor packaging materials interaction and reliability

    Chen, Andrea


    In semiconductor manufacturing, understanding how various materials behave and interact is critical to making a reliable and robust semiconductor package. Semiconductor Packaging: Materials Interaction and Reliability provides a fundamental understanding of the underlying physical properties of the materials used in a semiconductor package. The book focuses on an important step in semiconductor manufacturing--package assembly and testing. It covers the basics of material properties and explains how to determine which behaviors are important to package performance. The authors also discuss how

  16. Hardware and software reliability estimation using simulations

    Swern, Frederic L.


    The simulation technique is used to explore the validation of both hardware and software. It was concluded that simulation is a viable means for validating both hardware and software and associating a reliability number with each. This is useful in determining the overall probability of system failure of an embedded processor unit, and improving both the code and the hardware where necessary to meet reliability requirements. The methodologies were proved using some simple programs, and simple hardware models.

  17. System Reliability for LED-Based Products

    Davis, J Lynn; Mills, Karmann; Lamvik, Michael; Yaga, Robert; Shepherd, Sarah D; Bittle, James; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy; Johnson, Cortina; Evans, Amy


    Results from accelerated life tests (ALT) on mass-produced commercially available 6” downlights are reported along with results from commercial LEDs. The luminaires capture many of the design features found in modern luminaires. In general, a systems perspective is required to understand the reliability of these devices since LED failure is rare. In contrast, components such as drivers, lenses, and reflector are more likely to impact luminaire reliability than LEDs.

  18. The Revised Junior Eysenck Personality Questionnaire (JEPQ-R): Dutch replications of the full length, short, and abbreviated forms

    Scholte, R.H.J.; Bruyn, E.E.J. De


    This study examines the full-length, short and abbreviated forms of the Revised Junior Eysenck Personality Questionnaire (JEPQ-R) in a Dutch sample of 215 boys and 207 girls, aged 12–14. The reliability and concurrent validity of the scales of the full-length form (JEPQ-R, 81 items), short form (JEP




    Full Text Available Reliability is the probability that a system, component or device will perform without failure for a specified period of time under specified operating conditions. The concept of reliability is of great importance in the design of various machine members. Conventional engineering design uses a deterministic approach. It disregards the fact that the material properties, the dimensions of the components and the externally applied loads are statistical in nature. In conventional design this uncertainties are covered with a factor of safety, which is not always successful. The growing trend towards reducing uncertainty and increasing reliability is to use the probabilistic approach. In the present work a three shaft four speed gear box and six speed gear box are designed using reliability principles. For the specified reliability of the system (Gear box, component reliability (Gear pair is calculated by considering the system as a series system. Design is considered to be safe and adequate if the probability of failure of gear box is less than or equal to a specified quantity in each of the two failure modes. . All the parameters affecting the design are considered as random variables and all the random variables are assumed to follow normal distribution. A computer program in C++ is developed to calculate the face widths in bending and surface failure modes. The larger one out of the two values is considered. By changing the variations in the design parameters, variations in the face widths are studied.

  20. Reliability Analysis of High Rockfill Dam Stability

    Ping Yi


    Full Text Available A program 3DSTAB combining slope stability analysis and reliability analysis is developed and validated. In this program, the limit equilibrium method is utilized to calculate safety factors of critical slip surfaces. The first-order reliability method is used to compute reliability indexes corresponding to critical probabilistic surfaces. When derivatives of the performance function are calculated by finite difference method, the previous iteration’s critical slip surface is saved and used. This sequential approximation strategy notably improves efficiency. Using this program, the stability reliability analyses of concrete faced rockfill dams and earth core rockfill dams with different heights and different slope ratios are performed. The results show that both safety factors and reliability indexes decrease as the dam’s slope increases at a constant height and as the dam’s height increases at a constant slope. They decrease dramatically as the dam height increases from 100 m to 200 m while they decrease slowly once the dam height exceeds 250 m, which deserves attention. Additionally, both safety factors and reliability indexes of the upstream slope of earth core rockfill dams are higher than that of the downstream slope. Thus, the downstream slope stability is the key failure mode for earth core rockfill dams.

  1. Multi-Disciplinary System Reliability Analysis

    Mahadevan, Sankaran; Han, Song


    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code developed under the leadership of NASA Lewis Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multi-disciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  2. Effect of Maintenance on Computer Network Reliability

    Rima Oudjedi Damerdji


    Full Text Available At the time of the new information technologies, computer networks are inescapable in any large organization, where they are organized so as to form powerful internal means of communication. In a context of dependability, the reliability parameter proves to be fundamental to evaluate the performances of such systems. In this paper, we study the reliability evaluation of a real computer network, through three reliability models. The computer network considered (set of PCs and server interconnected is localized in a company established in the west of Algeria and dedicated to the production of ammonia and fertilizers. The result permits to compare between the three models to determine the most appropriate reliability model to the studied network, and thus, contribute to improving the quality of the network. In order to anticipate system failures as well as improve the reliability and availability of the latter, we must put in place a policy of adequate and effective maintenance based on a new model of the most common competing risks in maintenance, Alert-Delay model. At the end, dependability measures such as MTBF and reliability are calculated to assess the effectiveness of maintenance strategies and thus, validate the alert delay model.

  3. Short bowel syndrome in adults

    Matarese, Laura E; Jeppesen, Palle B; O'Keefe, Stephen J D


    Short bowel syndrome (SBS) is a heterogeneous disorder with broad variation in disease severity arising from different types of intestinal resection. The spectrum of malabsorption ranges from intestinal insufficiency to intestinal failure. Individualized patient strategies involving modifications...

  4. The classification on short message


    This paper discusses the importance of the classification of short message, and details some key technologies related. Through implementing a fundamental prototype, some basic models and technical references are provided.

  5. Cyclization of short DNA fragments

    Lam, Pui-Man; Zhen, Yi


    From the per unit length free energy for DNA under tension, we have calculated an effective contour length dependent persistence length for short DNA. This effective persistence length results from the enhanced fluctuations in short DNA. It decreases for shorter DNA, making shorter DNA more flexible. The results of the J-factor calculated using this effective persistence length are in good agreement with experimental data.

  6. On the reliability of the nervous (Nv) nets

    Beiu, V.; Frigo, J.R.; Moore, K.R.


    This paper investigates the reliability of a particular class of neural networks, the Nervous Nets (Nv). This is the class of nonsymmetric ring oscillator networks of inverters coupled through variable delays. They have been successfully applied to controlling walking robots, while many other applications will shortly be mentioned. The authors will then explain the robustness of Nv nets in the sense of their highly reliable functioning--which has been observed through many experiments. For doing that the authors will show that although the Nv net has an exponential number of periodic points, only a small (still exponential) part are stable, while all the others are saddle points. The ratio between the number of stable and periodic points quickly vanishes to zero as the number of nodes is increased, as opposed to classical finite state machines--where this ratio is relatively constant. These show that the Nv net will always converge quickly to a stable oscillatory state--a fact not true in general for finite state machines.

  7. reliability reliability


    The design variables for the design of the sla. The design ... The presence of uncertainty in the analysis and de of engineering .... however, for certain complex elements, the methods ..... Standard BS EN 1990, CEN, European Committee for.

  8. Reliability in automotive and mechanical engineering determination of component and system reliability

    Bertsche, Bernd


    In the present contemporary climate of global competition in every branch of engineering and manufacture it has been shown from extensive customer surveys that above every other attribute, reliability stands as the most desired feature in a finished product. To survive this relentless fight for survival any organisation, which neglect the plea of attaining to excellence in reliability, will do so at a serious cost Reliability in Automotive and Mechanical Engineering draws together a wide spectrum of diverse and relevant applications and analyses on reliability engineering. This is distilled into this attractive and well documented volume and practising engineers are challenged with the formidable task of simultaneously improving reliability and reducing the costs and down-time due to maintenance. The volume brings together eleven chapters to highlight the importance of the interrelated reliability and maintenance disciplines. They represent the development trends and progress resulting in making this book ess...

  9. Short-Message Quantize-Forward Network Coding

    Kramer, Gerhard


    Compression via quantization and hashing lets relays form distributed "multi-output" nodes of a multi-input, multi-output (MIMO) system. Recent work shows that quantize-forward (QF) with long-message encoding and decoding achieves the same reliable rates as short-message compress-forward (CF). It is shown that short-message QF with backward or pipelined (sliding-window) decoding also achieve the same rates for a single-relay channel. The price paid is a more restrictive quantization that degrades performance for slow-fading channels with outage. For many relays and sources, short-message QF with backward decoding achieves the same rates as long-message QF, although again with a more restrictive quantization. Several practical advantages of short-message encoding are pointed out, e.g., reduced delay (enabling streaming) and simplified modulation (without requiring additional hashing). Furthermore, short-message encoding lets relays use decode-forward (DF) if their channel quality is good, and therefore enables...

  10. MCTSSA Software Reliability Handbook, Volume III: Integration of Software Metrics with Quality and Reliability

    Schneidewind, Norman F.


    The purpose of this handbook is threefold. Specifically, it: (1) Serves as a reference guide for implementing standard software reliability practices at Marine Corps Tactical Systems Support Activity and aids in applying the software reliability model. (2) Serves as a tool for managing the software reliability program. (3) Serves as a training aid. U.S. Marine Corps Tactical Systems Support Activity, Camp Pendleton, CA. RLACH

  11. Experts’ Opinions on the Reliability Gap and Some Practical Guidelines on Reliability Growth


    Juran " (36:21). The following seven points explain the basic elements of Taguchi’s quality philosophy: 1. An important dimension of the quality of a...guidelines (experts’ point of view) for an effective reliability program (Questions 6 to 10 ) During the interviews, I asked the experts to rank order...reliability starting point would you use? Would you use a starting reliability value of 10 % of the cumulative Mean Time Between Maintenance (Inherent)? 20

  12. Reliability Degradation Due to Stockpile Aging

    Robinson, David G.


    The objective of this reseach is the investigation of alternative methods for characterizing the reliability of systems with time dependent failure modes associated with stockpile aging. Reference to 'reliability degradation' has, unfortunately, come to be associated with all types of aging analyes: both deterministic and stochastic. In this research, in keeping with the true theoretical definition, reliability is defined as a probabilistic description of system performance as a funtion of time. Traditional reliability methods used to characterize stockpile reliability depend on the collection of a large number of samples or observations. Clearly, after the experiments have been performed and the data has been collected, critical performance problems can be identified. A Major goal of this research is to identify existing methods and/or develop new mathematical techniques and computer analysis tools to anticipate stockpile problems before they become critical issues. One of the most popular methods for characterizing the reliability of components, particularly electronic components, assumes that failures occur in a completely random fashion, i.e. uniformly across time. This method is based primarily on the use of constant failure rates for the various elements that constitute the weapon system, i.e. the systems do not degrade while in storage. Experience has shown that predictions based upon this approach should be regarded with great skepticism since the relationship between the life predicted and the observed life has been difficult to validate. In addition to this fundamental problem, the approach does not recognize that there are time dependent material properties and variations associated with the manufacturing process and the operational environment. To appreciate the uncertainties in predicting system reliability a number of alternative methods are explored in this report. All of the methods are very different from those currently used to assess

  13. Effect of Random Thermal Spikes on Stirling Convertor Heater Head Reliability

    Shah, Ashwin R.; Korovaichuk, Igor; Halford, Gary R.


    Onboard radioisotope power systems being developed to support future NASA exploration missions require reliable design lifetimes of up to 14 yr and beyond. The structurally critical heater head of the high-efficiency developmental Stirling power convertor has undergone extensive computational analysis of operating temperatures (up to 650 C), stresses, and creep resistance of the thin-walled Inconel 718 bill of material. Additionally, assessment of the effect of uncertainties in the creep behavior of the thin-walled heater head, the variation in the manufactured thickness, variation in control temperature, and variation in pressure on the durability and reliability were performed. However, it is possible for the heater head to experience rare incidences of random temperature spikes (excursions) of short duration. These incidences could occur randomly with random magnitude and duration during the desired mission life. These rare incidences could affect the creep strain rate and therefore the life. The paper accounts for these uncertainties and includes the effect of such rare incidences, random in nature, on the reliability. The sensitivities of variables affecting the reliability are quantified and guidelines developed to improve the reliability are outlined. Furthermore, the quantified reliability is being verified with test data from the accelerated benchmark tests being conducted at the NASA Glenn Research Center.

  14. Timed Up and Go Test: A Reliable and Valid Test in Patients With Chronic Heart Failure.

    Hwang, Rita; Morris, Norman R; Mandrusiak, Allison; Mudge, Alison; Suna, Jessica; Adsett, Julie; Russell, Trevor


    The timed up and go test (TUGT) is a short-duration functional test frequently used in rehabilitation settings as a measure of balance and mobility. Reliability and validity for patients with chronic heart failure (CHF) has yet to be determined. This prospective cohort study aimed to determine test-retest reliability of the TUGT in patients with CHF, relationships between the TUGT and other variables, including functional tests, and predictors of the TUGT. This was a secondary analysis of data collected in a multicenter randomized controlled trial of exercise training in recently hospitalized patients with heart failure (EJECTION-HF). The TUGT was conducted twice at baseline to determine reliability. Assessments were compared with 6-minute walk distance (6MWD), 10-m walk test time, and other clinical variables. Intraclass correlation coefficient (ICC) was used to determine test-retest reliability and correlations for relationships with other variables. A multiple regression was used to identify predictors of the TUGT. In 278 participants (mean age 62 years), the TUGT demonstrated excellent within-day test-retest reliability (ICC 0.93). A shorter (better) TUGT time was associated with longer 6MWD (r = -0.81; P time (rs = 0.80; P < .001). Best predictors of the TUGT were 6MWD and age, which accounted for 66% of the variance. The TUGT appears to be a reliable and valid functional measurement in patients with CHF. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  15. Classifying Open-Ended Reports: Factors Affecting the Reliability of Occupation Codes

    Conrad Frederick G.


    Full Text Available A source of survey processing error that has received insufficient study to date is the misclassification of open-ended responses. We report on efforts to understand the misclassification of open occupation descriptions in the Current Population Survey (CPS. We analyzed double-coded CPS descriptions to identify which features vary with intercoder reliability. One factor strongly related to reliability was the length of the occupation description: longer descriptions were less reliably coded than shorter ones. This effect was stronger for particular occupation terms. We then carried out an experiment to examine the joint effects of description length and classification “difficulty” of particular occupation terms. For easy occupation terms longer descriptions were less reliably coded, but for difficult occupation terms longer descriptions were slightly more reliably coded than short descriptions. Finally, we observed as coders provided verbal reports on their decision making. One practice, evident in coders’ verbal reports, is their use of informal coding rules based on superficial features of the description. Such rules are likely to promote reliability, though not necessarily validity, of coding. To the extent that coders use informal rules for long descriptions involving difficult terms, this could help explain the observed relationship between description length and difficulty of coding particular terms.

  16. Culture Representation in Human Reliability Analysis

    David Gertman; Julie Marble; Steven Novack


    Understanding human-system response is critical to being able to plan and predict mission success in the modern battlespace. Commonly, human reliability analysis has been used to predict failures of human performance in complex, critical systems. However, most human reliability methods fail to take culture into account. This paper takes an easily understood state of the art human reliability analysis method and extends that method to account for the influence of culture, including acceptance of new technology, upon performance. The cultural parameters used to modify the human reliability analysis were determined from two standard industry approaches to cultural assessment: Hofstede’s (1991) cultural factors and Davis’ (1989) technology acceptance model (TAM). The result is called the Culture Adjustment Method (CAM). An example is presented that (1) reviews human reliability assessment with and without cultural attributes for a Supervisory Control and Data Acquisition (SCADA) system attack, (2) demonstrates how country specific information can be used to increase the realism of HRA modeling, and (3) discusses the differences in human error probability estimates arising from cultural differences.

  17. Process control using reliability based control charts

    J.K. Jacob


    Full Text Available Purpose: The paper presents the method to monitor the mean time between failures (MTBF and detect anychange in intensity parameter. Here, a control chart procedure is presented for process reliability monitoring.Control chart based on different distributions are also considered and were used in decision making. Results anddiscussions are presented based on the case study at different industries.Design/methodology/approach: The failure occurrence process can be modeled by different distributions likehomogeneous Poisson process, Weibull model etc. In each case the aim is to monitor the mean time betweenfailure (MTBF and detect any change in intensity parameter. When the process can be described by a Poissonprocess the time between failures will be exponential and can be used for reliability monitoring.Findings: In this paper, a new procedure based on the monitoring of time to observe r failures is also proposedand it can be more appropriate for reliability monitoring.Practical implications: This procedure is useful and more sensitive when compared with the λ-chart although itwill wait until r failures for a decision. These charts can be regarded as powerful tools for reliability monitoring.λr gives more accurate results than λ-chart.Originality/value: Adopting these measures to system of equipments can increase the reliability and availabilityof the system results in economic gain. A homogeneous Poisson process is usually used to model the failureoccurrence process with certain intensity.

  18. Dynamic reliability of digital-based transmitters

    Brissaud, Florent, E-mail: florent.brissaud.2007@utt.f [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France) and Universite de Technologie de Troyes - UTT, Institut Charles Delaunay - ICD and UMR CNRS 6279 STMR, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France); Smidts, Carol [Ohio State University (OSU), Nuclear Engineering Program, Department of Mechanical Engineering, Scott Laboratory, 201 W 19th Ave, Columbus OH 43210 (United States); Barros, Anne; Berenguer, Christophe [Universite de Technologie de Troyes (UTT), Institut Charles Delaunay (ICD) and UMR CNRS 6279 STMR, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France)


    Dynamic reliability explicitly handles the interactions between the stochastic behaviour of system components and the deterministic behaviour of process variables. While dynamic reliability provides a more efficient and realistic way to perform probabilistic risk assessment than 'static' approaches, its industrial level applications are still limited. Factors contributing to this situation are the inherent complexity of the theory and the lack of a generic platform. More recently the increased use of digital-based systems has also introduced additional modelling challenges related to specific interactions between system components. Typical examples are the 'intelligent transmitters' which are able to exchange information, and to perform internal data processing and advanced functionalities. To make a contribution to solving these challenges, the mathematical framework of dynamic reliability is extended to handle the data and information which are processed and exchanged between systems components. Stochastic deviations that may affect system properties are also introduced to enhance the modelling of failures. A formalized Petri net approach is then presented to perform the corresponding reliability analyses using numerical methods. Following this formalism, a versatile model for the dynamic reliability modelling of digital-based transmitters is proposed. Finally the framework's flexibility and effectiveness is demonstrated on a substantial case study involving a simplified model of a nuclear fast reactor.

  19. Achieving Reliable Communication in Dynamic Emergency Responses

    Chipara, Octav; Plymoth, Anders N.; Liu, Fang; Huang, Ricky; Evans, Brian; Johansson, Per; Rao, Ramesh; Griswold, William G.


    Emergency responses require the coordination of first responders to assess the condition of victims, stabilize their condition, and transport them to hospitals based on the severity of their injuries. WIISARD is a system designed to facilitate the collection of medical information and its reliable dissemination during emergency responses. A key challenge in WIISARD is to deliver data with high reliability as first responders move and operate in a dynamic radio environment fraught with frequent network disconnections. The initial WIISARD system employed a client-server architecture and an ad-hoc routing protocol was used to exchange data. The system had low reliability when deployed during emergency drills. In this paper, we identify the underlying causes of unreliability and propose a novel peer-to-peer architecture that in combination with a gossip-based communication protocol achieves high reliability. Empirical studies show that compared to the initial WIISARD system, the redesigned system improves reliability by as much as 37% while reducing the number of transmitted packets by 23%. PMID:22195075

  20. On the reliability of seasonal climate forecasts.

    Weisheimer, A; Palmer, T N


    Seasonal climate forecasts are being used increasingly across a range of application sectors. A recent UK governmental report asked: how good are seasonal forecasts on a scale of 1-5 (where 5 is very good), and how good can we expect them to be in 30 years time? Seasonal forecasts are made from ensembles of integrations of numerical models of climate. We argue that 'goodness' should be assessed first and foremost in terms of the probabilistic reliability of these ensemble-based forecasts; reliable inputs are essential for any forecast-based decision-making. We propose that a '5' should be reserved for systems that are not only reliable overall, but where, in particular, small ensemble spread is a reliable indicator of low ensemble forecast error. We study the reliability of regional temperature and precipitation forecasts of the current operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts, universally regarded as one of the world-leading operational institutes producing seasonal climate forecasts. A wide range of 'goodness' rankings, depending on region and variable (with summer forecasts of rainfall over Northern Europe performing exceptionally poorly) is found. Finally, we discuss the prospects of reaching '5' across all regions and variables in 30 years time.