Network reconfiguration of distribution systems using metaheuristics and reliability measures

In an evermore competitive environment, power distribution companies need to continuously monitor and improve the reliability indices of their systems. The network reconfiguration (NR) of a distribution system is a technique that well adapts to this new deregulated environment for it allows improvement of system reliability indices without the onus involved in procuring new equipment. This paper presents a reliability-based NR methodology that uses metaheuristic techniques to search for the optimal network configuration. Three metaheuristics, i.e. Tabu Search, Evolution Strategy, and Differential Evolution, are tested using a Brazilian distribution network and the results are discussed. © 2009 IEEE.

Improved ground motion intensity measures for reliability-based demand analysis of structures

In Performance-Based Earthquake Engineering (PBEE), evaluating the seismic performance (or seismic risk) of a structure at a designed site has gained major attention, especially in the past decade. One of the objectives in PBEE is to quantify the seismic reliability of a structure (due to the future random earthquakes) at a site. For that purpose, Probabilistic Seismic Demand Analysis (PSDA) is utilized as a tool to estimate the Mean Annual Frequency (MAF) of exceeding a specified value of a structural Engineering Demand Parameter (EDP). This dissertation focuses mainly on applying an average of a certain number of spectral acceleration ordinates in a certain interval of periods, Sa,avg (T1,…,Tn), as scalar ground motion Intensity Measure (IM) when assessing the seismic performance of inelastic structures. Since the interval of periods where computing Sa,avg is related to the more or less influence of higher vibration modes on the inelastic response, it is appropriate to speak about improved IMs. The results using these improved IMs are compared with a conventional elastic-based scalar IMs (e.g., pseudo spectral acceleration, Sa ( T(¹)), or peak ground acceleration, PGA) and the advanced inelastic-based scalar IM (i.e., inelastic spectral displacement, Sdi). The advantages of applying improved IMs are: (i ) "computability" of the seismic hazard according to traditional Probabilistic Seismic Hazard Analysis (PSHA), because ground motion prediction models are already available for Sa (Ti), and hence it is possibile to employ existing models to assess hazard in terms of Sa,avg, and (ii ) "efficiency" or smaller variability of structural response, which was minimized to assess the optimal range to compute Sa,avg. More work is needed to assess also "sufficiency" and "scaling robustness" desirable properties, which are disregarded in this dissertation. However, for ordinary records (i.e., with no pulse like effects), using the improved IMs is found to be more accurate than using the elastic- and inelastic-based IMs. For structural demands that are dominated by the first mode of vibration, using Sa,avg can be negligible relative to the conventionally-used Sa (T(¹)) and the advanced Sdi. For structural demands with sign.cant higher-mode contribution, an improved scalar IM that incorporates higher modes needs to be utilized. In order to fully understand the influence of the IM on the seismis risk, a simplified closed-form expression for the probability of exceeding a limit state capacity was chosen as a reliability measure under seismic excitations and implemented for Reinforced Concrete (RC) frame structures. This closed-form expression is partuclarly useful for seismic assessment and design of structures, taking into account the uncertainty in the generic variables, structural "demand" and "capacity" as well as the uncertainty in seismic excitations. The assumed framework employs nonlinear Incremental Dynamic Analysis (IDA) procedures in order to estimate variability in the response of the structure (demand) to seismic excitations, conditioned to IM. The estimation of the seismic risk using the simplified closed-form expression is affected by IM, because the final seismic risk is not constant, but with the same order of magnitude. Possible reasons concern the non-linear model assumed, or the insufficiency of the selected IM. Since it is impossibile to state what is the "real" probability of exceeding a limit state looking the total risk, the only way is represented by the optimization of the desirable properties of an IM.

Incorporating reliability measurements into the predictions of a recommender system

In this paper we introduce the idea of using a reliability measure associated to the predic- tions made by recommender systems based on collaborative filtering. This reliability mea- sure is based on the usual notion that the more reliable a prediction, the less liable to be wrong. Here we will define a general reliability measure suitable for any arbitrary recom- mender system. We will also show a method for obtaining specific reliability measures specially fitting the needs of different specific recommender systems.

Reliability measures for local nodes assessment in classification trees

Most of the modem developments with classification trees are aimed at improving their predictive capacity. This article considers a curiously neglected aspect of classification trees, namely the reliability of predictions that come from a given classification tree. In the sense that a node of a tree represents a point in the predictor space in the limit, the aim of this article is the development of localized assessment of the reliability of prediction rules. A classification tree may be used either to provide a probability forecast, where for each node the membership probabilities for each class constitutes the prediction, or a true classification where each new observation is predictively assigned to a unique class. Correspondingly, two types of reliability measure will be derived-namely, prediction reliability and classification reliability. We use bootstrapping methods as the main tool to construct these measures. We also provide a suite of graphical displays by which they may be easily appreciated. In addition to providing some estimate of the reliability of specific forecasts of each type, these measures can also be used to guide future data collection to improve the effectiveness of the tree model. The motivating example we give has a binary response, namely the presence or absence of a species of Eucalypt, Eucalyptus cloeziana, at a given sampling location in response to a suite of environmental covariates, (although the methods are not restricted to binary response data).

Avaliação do cuidado de enfermagem na perspectiva da segurança do paciente em unidades de terapia intensiva: na visão de profissionais, pacientes e familiares

Technological advances combined with healthcare assistance bring increased risks related to patient safety, causing health institutions to be environments susceptible to losses in the provided care. Sectors of high complexity, such as Intensive Care Units have such characteristics highlighted due to being spaces designed for the care of patients in serious medical condition, when the use of advanced technological devices becomes a necessity. Thus, the aim of this study was to assess nursing care from the perspective of patient safety in intensive care units. This is an evaluative research, which combines various forms of data collection and analysis in order to conduct a deepened investigation. Data collection occurred in loco, from April to July 2014 in hospitals equipped with adult intensive care unit services. For this, a checklist instrument and semi-structured interviews conducted with patients, families, professionals were used in order to evaluate the structure-process-outcome triad. The instrument for nursing care assessment regarding Patient Safety included 97 questions related to structure and processes. Interviews provided data for outcome analysis. The selection of interviewees/participants was based on the willingness of potential participants. The following methods were used to collect data resulting from the instrument: statistical analysis of inter-rater reliability measure known as kappa (K); observations from judges resulting from the observation process; and added information obtained from the literature on the thematic. Data analysis from the interviews was carried out with IRAMUTEQ software, which used Descending Hierarchical Classification and Similarity analysis to aid in data interpretation. Research steps followed the ethical principles presented by Resolution No. 466 of December 12, 2012, and the results were presented in three manuscripts: 1) Evaluation of patient safety in Intensive Care Units: a focus on structure; 2) Health evaluation processes: a nursing care perspective on patient safety; 3) Patient safety in intensive care units: perception of nurses, family members and patients. The first article, related to the structure, refers to the use of 24 items of the employed instrument, showing that most of the findings were not aligned with the adequacy standards, which indicates poor conditions in structures offered in health services. The second article provides an analysis of the pillar of Processes, with the use of 73 items of the instrument, showing that 50 items did not meet the required standards for safe handling due to the absence of adequate scientific guidance and effective communication in nursing care process. For the third article, results indicate that intensive care units were safe places, yet urges for changes, especially in the physical structure and availability of materials and communication among professionals, patients and families. Therefore, our findings suggest that the nursing care being provided in the evaluated intensive care units contains troubling shortcomings with regards to patient safety, thereby evidencing an insecure setting for the assistance offered, in addition to a need for urgent measures to remedy the identified inadequacies with appropriate structures and implement protocols and care guidelines in order to consolidate an environment more favorable to patient safety.

Reliability and validity of scores on scales to measure managerial aspirations

The present investigation assessed the reliability and validity of the scores of a subjective measure of desired aspirations and a behavioral measure of enacted aspirations. A sample of 5,655 employees was randomly split into two halves. Principal components analysis on Sample 1, followed by confirmatory factor analysis on Sample 2, confirmed the desired and enacted scales as distinct but related measures of managerial aspirations. The desired and enacted scales had satisfactory levels of internal consistency and temporal stability over a 1-year period. Relationships between the measures of desired and enacted managerial aspirations and both attitudinal and behavioral criteria, measured concurrently and 1 year later, provided preliminary support for convergent and discriminant validity for our sample. Desired aspirations demonstrated stronger validity than enacted aspirations. Although further examination of the psychometric properties of the scales is warranted, the present findings provide promising support for their validity and reliability for our sample.

Brazilian version of the Functional Assessment Measure: cross-cultural adaptation and reliability evaluation

The objective of this prospective study was to perform a cross-cultural adaptation of the Functional Assessment Measure (FAM) into Brazilian Portuguese, and to assess the test-retest reliability. The instrument was translated, back-translated, pretested, and reviewed by a committee. The Brazilian version was assessed in 61 brain-injury patients. Intrarater and interrater reliability was verified by a test-retest procedure (intraclass correlation). Intrarater reliability was moderate-to-excellent; interrater reliability was moderate-to-excellent, with the exception of one item. The Brazilian version of the FAM has acceptable test-retest reliability. Results suggest the use of the Brazilian version of the FAM in the Brazilian population, for disability evaluation and outcome assessment. Further research is required to evaluate the psychometric properties of the scale. International Journal of Rehabilitation Research 34:89-91 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

A reliability-based measure of robustness for concrete structures subjected to corrosion

This work is a contribution to the definition and assessment of structural robustness. Special emphasis is given to reliability of reinforced concrete structures under corrosion of longitudinal reinforcement. On this communication several authors’ proposals in order to define and measure structural robustness are analyzed and discussed. The probabilistic based robustness index is defined, considering the reliability index decreasing for all possible damage levels. Damage is considered as the corrosion level of the longitudinal reinforcement in terms of rebar weight loss. Damage produces changes in both cross sectional area of rebar and bond strength. The proposed methodology is illustrated by means of an application example. In order to consider the impact of reinforcement corrosion on failure probability growth, an advanced methodology based on the strong discontinuities approach and an isotropic continuum damage model for concrete is adopted. The methodology consist on a two-step analysis: on the first step an analysis of the cross section is performed in order to capture phenomena such as expansion of the reinforcement due to the corrosion products accumulation and damage and cracking in the reinforcement surrounding concrete; on the second step a 2D deteriorated structural model is built with the results obtained on the first step of the analysis. The referred methodology combined with a Monte Carlo simulation is then used to compute the failure probability and the reliability index of the structure for different corrosion levels. Finally, structural robustness is assessed using the proposed probabilistic index.

Reliability of a new measure of motoneuron excitability

Objectlve:--This study examined the intraclass reliability· of different measures of the excitability of the Hoffmann reflex, derived from stimulus-response curves. The slope of the regression line of the H-reflex stimulus-response curve advocated by Funase et al. (1994) was also compared to the peak of the first derivative of the H-reflex stimulus-response curve (dHIdVmax), a new measure introduced in this investigation. A secondary purpose was to explore the possibility of mood as a covariate when measuring excitability of the H-reflex arc. Methods: The H-reflex amplitude at a stimulus intensity corresponding to 5% of the maximum M-wave (Mmax) is an established measure that was used as an additional basis of comparison. The H-reflex was elicited in the soleus for 24 subjects (12 males and 12 females) on five separate days. Vibration was applied to the Achilles tendon prior to stimulation to test the sensitivity of the measures on test day four. The means of five evoked potentials at each gradually increasing intensity, from below H-reflex threshold to above Mmax, were used to create both the H-reflex and M-wave stimulus response curves for each subject across test days. The mood of the subjects was assessed using the Subjective Exercise Experience Scale (SEES) prior to the stimulation protocol each day. Results: There was a modest decrease in all H-reflex measures from the first to third test day, but it was non-significant (P's>0.05). All measures of the H-reflex exhibited a profound reduction following vibration on test day four, and then returned to baseline levels on test day five (P's<0.05). The intraclass correlation coefficient (ICC) for H-reflex amplitude at 5% of Mmax was 0.85. The ICC for the slope of the regression line was 0.79 while it was 0.89 for dH/dVmax. Maximum M-wave amplitude had an ICC of 0.96 attesting to careful methodological controls. The SEES subscales of fatigue and psychological well-being remained unchanged IV across the five days. The psychological distress subscale (PO.05). Conclusions: The peak of the first derivative of the H-reflex stimulus-response curve (dH/dVmax) was shown to have comparable reliability and sensitivity to other more established measures of excitability. Psychological distress and the amplitude of the H-reflex at 5% Mmax follow similar trends across days, however there was no significant correlation between the two measures. Significance: The proposed method appears to be a more robust measure ofH-reflex excitability than the other methods tested. As such it would be an advantageous method to apply in clinical and investigative settings. Additionally, the results suggest that the relationship between psychological distress and H-reflex amplitude should be investigated further.

Reliability, construct and criterion validity of the KIDSCREEN-10 score: a short measure for children and adolescents' well-being and health-related quality of life

Background To assess the criterion and construct validity of the KIDSCREEN-10 well-being and health-related quality of life (HRQoL) score, a short version of the KIDSCREEN-52 and KIDSCREEN-27 instruments. Methods The child self-report and parent report versions of the KIDSCREEN-10 were tested in a sample of 22,830 European children and adolescents aged 8–18 and their parents (n = 16,237). Correlation with the KIDSCREEN-52 and associations with other generic HRQoL measures, physical and mental health, and socioeconomic status were examined. Score differences by age, gender, and country were investigated. Results Correlations between the 10-item KIDSCREEN score and KIDSCREEN-52 scales ranged from r = 0.24 to 0.72 (r = 0.27–0.72) for the self-report version (proxy-report version). Coefficients below r = 0.5 were observed for the KIDSCREEN-52 dimensions Financial Resources and Being Bullied only. Cronbach alpha was 0.82 (0.78), test–retest reliability was ICC = 0.70 (0.67) for the self- (proxy-)report version. Correlations between other children self-completed HRQoL questionnaires and KIDSCREEN-10 ranged from r = 0.43 to r = 0.63 for the KIDSCREEN children self-report and r = 0.22–0.40 for the KIDSCREEN parent proxy report. Known group differences in HRQoL between physically/mentally healthy and ill children were observed in the KIDSCREEN-10 self and proxy scores. Associations with self-reported psychosomatic complaints were r = −0.52 (−0.36) for the KIDSCREEN-10 self-report (proxy-report). Statistically significant differences in KIDSCREEN-10 self and proxy scores were found by socioeconomic status, age, and gender. Conclusions Our results indicate that the KIDSCREEN-10 provides a valid measure of a general HRQoL factor in children and adolescents, but the instrument does not represent well most of the single dimensions of the original KIDSCREEN-52. Test–retest reliability was slightly below a priori defined thresholds.

Validity and reliability of a measure of Latina mother's nutritional self-efficacy

Background. Not only has obesity played a role in Texas adults but it is also becoming a large issue among low-income Latino children. In Latino children between 2-5 years of age, the Pediatric Nutrition Surveillance data in 1997 found the prevalence of obesity was 12 percent, highest among all ethnic groups. Children learn what and how to eat from their environment. Despite many mothers being working mothers they are still the principal caregivers and source of influence on their toddler's diet. Self-efficacy, a concept created by Albert Bandura, one's belief that one is capable of performing a behavior needed to reach an intended goal, is increasingly becoming important in nutrition and health education. This study is important to understand the degree of impact that a mother's self-efficacy will have on a child's diet. This is useful knowing if influencing a mother's self-efficacy could improve a child's diet to prevent certain public health issues such as obesity and diabetes. The purpose of this study was to examine nutrition self-efficacy of Latina mothers, focusing on sweets and beverage and if their self-efficacy impacted their child's diet. Methods. The data was collected during July-September 2008. Mothers were recruited from two federally qualified San Antonio health centers. In order to qualify, participants had to be Hispanic with children of toddler age. Mothers were informed of incentives available upon completion. The interview consisted of demographic info, a set of five self-efficacy questions repeated at completion, testing reliability and a 24-hour food recall diary asked of the participant's child's diet. Results. There were 225 mothers who participated between both clinics. The Crohnbach alpha scores for the two different times the self-efficacy questions were asked were .44 corresponding to the first time and .49 for the second time. The three most common beverages reported were milk, juice, and water. The mothers who met or gave their child more milk than recommended by the scientific community, 800mg of calcium/3 cups (24oz) set, had a higher self-efficacy score than those who did not meet the standard at all. Mothers who gave their children more juice than the standard recommends, 4-6oz for children 1-6 years of age, had slightly higher self-efficacy scores than mother's who simply met the standard. In general, the lower the mother's self-efficacy, the more sweets they gave their child and vice versa. Conclusion. This study's Kappa values were adequate and this research showed that Latina mothers did in fact have high self-efficacy. In general some of the children's diets did not reflect the current scientific nutrition recommendations. In order to improve self-efficacy and have an impact on children's diets, the scientific community has a responsibility to make recommendations that are easily understood and can be put into practice. The public health community needs to ensure that we encourage those we serve to be more active in their health and educate them about what constitutes good health and nutrition for both themselves and their children.^

An examination of the cross-cultural reliability and construct validity of a measure of loneliness

Loneliness is a pervasive, rather common experience in American culture, particularly notable among adolescents. However, the phenomenon is not well documented in the cross-cultural psychiatric literature. For psychiatric epidemiology to encompass a wide array of psychopathologic phenomena, it is important to develop useful measures to characterize and classify both non-clinical and clinical dysfunction in diverse subgroups and cultures.^ The goal of this research was to examine the cross-cultural reliability and construct validity of a scale designed to measure loneliness. The Roberts Loneliness Scale (RLS-8) was administered to 4,060 adolescents ages 10-19 years enrolled in high schools along either side of the Texas-Tamaulipas border region between the U.S. and Mexico. Data collected in 1988 from a study focusing on substance use and psychological distress among adolescents in these regions were used to examine the operating characteristics of the RLS-8. A sample stratified by nationality and language, age, gender, and grade was used for analysis.^ Results indicated that in general the RLS-8 has moderate reliability in the U.S. sample, but not in the Mexican sample. Validity analyses demonstrated that there was evidence for convergent validity of the RLS-8 in the U.S. sample, but none in the Mexican sample. Discriminant validity of the measures in neither sample could be established. Based on the factor structure of the RLS-8, two subscales were created and analyzed for construct validity. Evidence for convergent validity was established for both subscales in both national samples. However, the discriminant validity of the measure remains unsubstantiated in both national samples. Also, the dimensionality of the scale is unresolved.^ One primary goal for future cross-cultural research would be to develop and test better defined culture-specific models of loneliness within the two cultures. From such scientific endeavor, measures of loneliness can be developed or reconstructed to classify the phenomenon in the same manner across cultures. Since estimates of prevalence and incidence are contingent upon reliable and valid screening or diagnostic measures, this objective would serve as an important foundation for future psychiatric epidemiologic inquiry into loneliness. ^

Reliability of a measure of prediagnosis physical activity for cancer survivors

Purpose: This study was conducted to examine the test-retest reliability of a measure of prediagnosis physical activity participation administered to colorecial cancer survivors recruited from a population-based state cancer registry. Methods: A total of 112 participants completed two telephone interviews. I month apart, reporting usual weekly physical activity in the year before their cancer diagnosis. Intraclass correlation coefficients (ICC) and standard en-or of measurement (SEM) were used to describe the test-retest reliability of the measure across the sample: the Bland-Altman approach was used to describe reliability at the individual level. The test-retest reliability for categorized total physical activity (active, insufficiently active, sedentary) was assessed using the kappa statistic. Results: When the complete sample was considered, the ICC ranged from 0.40 (95% Cl: 0.24, 0.55) for vigorous gardening to 0.77 (95% Cl: 0.68, 0.84) for moderate physical activity. The SEM, however, were large. indicating high measurement error. The Bland-Altman plots indicated that the reproducibility of data decreases as the aniount of physical activity reported each week increases The kappa coefficient for the categorized data was 0.62 (95% Cl: 0.48, 0.76). Conclusion: Overall. the results indicated low levels of repeatability for this measure of historical physical activity. Categorizing participants as active, insufficiently active, or sedentary provides a higher level of test-retest reliability.

The MacDQoL individualized measure of the impact of macular degeneration on quality of life: reliability and responsiveness

PURPOSE: To investigate the MacDQoL test-retest reliability and sensitivity to change in vision over a period of one year in a sample of patients with age-related macular degeneration (AMD). DESIGN: A prospective, observational study. METHOD: Patients with AMD from an ophthalmologist's list (n = 135) completed the MacDQoL questionnaire by telephone interview and underwent a vision assessment on two occasions, one year apart. RESULTS: Among participants whose vision was stable over one year (n = 87), MacDQoL scores at baseline and follow-up were highly correlated (r = 0.95; P < .0001). Twelve of the 22 scale items had intraclass correlations of >.80; only two were correlated <.7. There was no difference between baseline and follow-up scores (P = .85), indicating excellent test-retest reliability. Poorer quality of life (QoL) at follow-up, measured by the MacDQoL present QoL overview item, was associated with deterioration in both the better eye and binocular distance visual acuity [VA] (r = 0.29; P = .001, r = 0.21; P = .016, respectively; n = 135). There was a positive correlation between deterioration in the Mac. DQoL average weighted impact score and deterioration in both binocular near VA and reading speed (r = 0.20; P = .019, r = 0.18; P = .041, respectively; n = 135). CONCLUSION: The MacDQoL has excellent test-retest reliability. Its sensitivity to change in vision status was demonstrated in correlational analyses. The measure indicates that the negative impact of AMD on QoL increases with increasing severity of visual impairment.