Reliability of infrared thermography in skin temperature evaluation of wheelchair users

To examine the reliability of infrared thermography (IRT) in wheelchair users (WCUs), as a noninvasive and risk-free technique to detect the natural thermal radiation emitted by human skin and to allow subsequent interpretations of temperature distributions.

Reliability of graphite furnace atomic absorption spectrometry as alternative method for trace analysis of arsenic in natural medicinal products

Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry (GFAAS) and hydride generation atomic absorption spectrometry (HGAAS) for trace analysis of arsenic (As) in natural herbal products (NHPs). Method: Arsenic analysis in natural herbal products and standard reference material was conducted using atomic absorption spectrometry (AAS), namely, hydride generation AAS (HGAAS) and graphite furnace (GFAAS). The samples were digested with HNO3–H2O2 in a ratio of 4:1 using microwaveassisted acid digestion. The methods were validated with the aid of the standard reference material 1515 Apple Leaves (SRM) from NIST Results: Mean recovery of three different samples of NHPs, using HGAAS and GFAAS, ranged from 89.3 - 91.4 %, and 91.7 - 93.0 %, respectively. The difference between the two methods was insignificant. A (P= 0.5), B (P=0.4) and C (P=0.88) Relative standard deviation (RSD) RSD, i.e., precision was 2.5 - 6.5 % and 2.3 - 6.7 % using HGAAS and GFAAS techniques, respectively. Recovery of arsenic in SRM was 98 and 102 % by GFAAS and HGAAS, respectively. Conclusion: GFAAS demonstrates acceptable levels of precision and accuracy. Both techniques possess comparable accuracy and repeatability. Thus, the two methods are recommended as an alternative approach for trace analysis of arsenic in natural herbal products.

A preliminary adaptation of the Problem Gambling Severity Index for Indigenous Australians: internal reliability and construct validity

Objective: This paper describes the process employed to adapt the Problem Gambling Severity Index (PGSI) for use with Indigenous Australian populations.Methods: This study comprised a two-stage process: an initial consultation with Indigenous health workers, informing the textual and conceptual adaptation of items, followed by trial of the adjusted instrument with Indigenous community members (n=301).Results: Internal reliability was demonstrated: Australian Indigenous Problem Gambling Index (AIPGI) Cronbach's alpha α = 0.92 (Original PGSI, α = 0.84). Item-rest correlations confirmed that responses to items were consistent and related to the total score of remaining items. The AIPGI could predict gambling severity based on gambling frequency, when controlling for age and gender (OR=1.28, 95%CI 1.17–1.40).Conclusions: The adapted instrument is accessible to a cross-section of Indigenous Australians and has demonstrated properties of reliability and validity. An extended trial is needed to test the application of the instrument to a broader Indigenous audience and to further explore and confirm psychometric properties of the adapted instrument.Implications: This study introduces a culturally adapted tool for measuring rates of disordered gambling among Indigenous Australians.

The diagnostic validity and reliability of an internet-based clinical assessment program for mental disorders

BACKGROUND: Internet-based assessment has the potential to assist with the diagnosis of mental health disorders and overcome the barriers associated with traditional services (eg, cost, stigma, distance). Further to existing online screening programs available, there is an opportunity to deliver more comprehensive and accurate diagnostic tools to supplement the assessment and treatment of mental health disorders. OBJECTIVE: The aim was to evaluate the diagnostic criterion validity and test-retest reliability of the electronic Psychological Assessment System (e-PASS), an online, self-report, multidisorder, clinical assessment and referral system. METHODS: Participants were 616 adults residing in Australia, recruited online, and representing prospective e-PASS users. Following e-PASS completion, 158 participants underwent a telephone-administered structured clinical interview and 39 participants repeated the e-PASS within 25 days of initial completion. RESULTS: With structured clinical interview results serving as the gold standard, diagnostic agreement with the e-PASS varied considerably from fair (eg, generalized anxiety disorder: κ=.37) to strong (eg, panic disorder: κ=.62). Although the e-PASS' sensitivity also varied (0.43-0.86) the specificity was generally high (0.68-1.00). The e-PASS sensitivity generally improved when reducing the e-PASS threshold to a subclinical result. Test-retest reliability ranged from moderate (eg, specific phobia: κ=.54) to substantial (eg, bulimia nervosa: κ=.87). CONCLUSIONS: The e-PASS produces reliable diagnostic results and performs generally well in excluding mental disorders, although at the expense of sensitivity. For screening purposes, the e-PASS subclinical result generally appears better than a clinical result as a diagnostic indicator. Further development and evaluation is needed to support the use of online diagnostic assessment programs for mental disorders. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ACTRN121611000704998; http://www.anzctr.org.au/trial_view.aspx?ID=336143 (Archived by WebCite at http://www.webcitation.org/618r3wvOG).

The Gambling Urge Scale : reliability and validity in a clinical population

The aim of this study was to establish reliability and validity of the Gambling Urge Scale (GUS) in a clinical population of problem gamblers. This cohort study was conducted in South Australia between March 2008 and March 2009. Participants were problem gamblers aged ≥18 years (n = 158) who were seeking treatment from a range of gambling help services. Measures included gambling urge, problem gambling screening, gambling behaviour and problems caused by gambling, such as personal health and relationships. The psychometric properties investigated were internal reliability, criterion-related validity, concurrent validity and construct validity. Results showed high internal consistency for GUS (α = 0.93) and significant item-rest correlations ranging from 0.72 to 0.86. For criterion-related validity, a GUS cut score of three correctly classified 81.13% of participants as problem gambling with sensitivity 84.75% and specificity 76.6%. Concurrent validity was significant with a number of gambling-related symptoms and problems including psychological disturbance, work and social functioning and gambling-related cognitions (p < 0.001). An insignificant correlation was found between gambling urge and sensation seeking traits (p = 0.663). When controlling for gender and age the instrument was shown to have significant predictive properties for different levels of gambling severity (p < 0.001). A principal component analysis for the one component showed an overall explained variance of 75.54%. These findings indicate that GUS is a valid and reliable instrument for problem gambling screening, to measure treatment outcomes and may predict relapse in problem gambling.

Validity and reliability of questionnaires measuring physical activity self-efficacy, enjoyment, social support among Hong Kong Chinese children

BACKGROUND: Physical activity (PA) correlates have not been extensively studied in Hong Kong children.

OBJECTIVE: The aim of this study is to assess the validity and reliability of translated scales to measure PA related self-efficacy, enjoyment and social support in Hong Kong Chinese children.

METHODS: Sample 1 (n = 273, aged 8-12 years) was recruited (May-June, 2013) from two primary schools. Confirmatory factor analyses (CFA) were conducted to assess factorial validity. Criterion validity was assessed by correlating measured constructs with self-reported PA. Cronbach's alpha was computed to assess scale internal consistency. The intraclass correlation coefficient (ICC) was performed to assess scale test-retest reliability. Criterion validity was further examined in Sample 2 (n = 84, aged 8-12 years) from a third school by correlating measured constructs with objectively measured PA collected in September 2013 and February 2014.

RESULTS: The CFA results supported the one-factor structure of the scales. All PA correlates were significantly (p < 0.01) associated with self-reported PA in Sample 1. Self-efficacy and enjoyment were significantly (p < 0.05) correlated with objectively measured PA in Sample 2. All the scales demonstrated acceptable internal consistency. All ICC values of the scales suggested acceptable test-retest reliability.

CONCLUSION: The results provide psychometric support for using the scales to measure PA correlates among Hong Kong Chinese children.

Reliability of the nociceptive flexor reflex (RIII) threshold and association with pain threshold

The purpose of this study was to assess the reliability of the RIII reflex threshold and Pain threshold in three repeated trials using electrocutaneous stimuli. Each trial was separated by a mean of 4.3 +/- 2.9 days (between-trials) and included two repeated measurements (within-trial) of the RIII reflex threshold (RIII-T) and the Pain threshold (PT) separated by 20 min. The participants were 14 healthy males (mean age +/- SD, 23.5 +/- 5.3 years). There was a significant difference between the RIII-T and PT. The reliability of the RIII-T and PT shows a between-trials coefficient of variance (CV(SEM)) of 16.1 and 16.9%, respectively. The within-trial CV(SEM) for RIII-T and PT was 5.4 and 4.3%, respectively. There was a significant correlation between the RIII-T threshold and PT. The parallel association and correlation of the RIII-T with the PT suggests that the RIII-T is valid in experimental pain studies under standardised resting conditions.

Reliability-aware distributed computing scheduling policy

One of the primary issues associated with the efficient and effective utilization of distributed computing is resource management and scheduling. As distributed computing resource failure is a common occurrence, the issue of deploying support for integrated scheduling and fault-tolerant approaches becomes paramount importance. To this end, we propose a fault-tolerant dynamic scheduling policy that loosely couples dynamic job scheduling with job replication scheme such that jobs are efficiently and reliably executed. The novelty of the proposed algorithm is that it uses passive replication approach under high system load and active replication approach under low system loads. The switch between these two replication methods is also done dynamically and transparently. Performance evaluation of the proposed fault-tolerant scheduler and a comparison with similar fault-tolerant scheduling policy is presented and shown that the proposed policy performs better than the existing approach.

Setting the record straight: assessing the reliability of retrospective accounts of change

Conservation Letters published by Wiley Periodicals, Inc. Ecological degradation is accelerating, reducing our ability to detect and reverse declines. Resource user accounts have the potential to provide critical information on past change but their reliability can rarely be tested, hence they are often perceived as less valid than other forms of scientific data. We compared individual fishers' catch records, recorded 1-50 years ago, with their memories of past good, typical and poor catches for the corresponding time period. Good and poor catches were recalled with reasonable accuracy, matching variability in recorded catch with no significant change observed over time. Typical recalled catches were overestimated and became significantly more exaggerated over time, but were more comparable to mean than median recorded values. While accuracy of resource users' memory varied with the type of information recalled, our results suggest that carefully structured interview questions can produce reliable quantitative data to inform resource management, even after several decades have elapsed.

Validity and reliability of a pictorial instrument for assessing perceived motor competence in Portuguese children

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

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

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

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

Reliability evaluation for clustered WSNs under malware propagation

We consider a clustered wireless sensor network (WSN) under epidemic-malware propagation conditions and solve the problem of how to evaluate its reliability so as to ensure efficient, continuous, and dependable transmission of sensed data from sensor nodes to the sink. Facing the contradiction between malware intention and continuous-time Markov chain (CTMC) randomness, we introduce a strategic game that can predict malware infection in order to model a successful infection as a CTMC state transition. Next, we devise a novel measure to compute the Mean Time to Failure (MTTF) of a sensor node, which represents the reliability of a sensor node continuously performing tasks such as sensing, transmitting, and fusing data. Since clustered WSNs can be regarded as parallel-serial-parallel systems, the reliability of a clustered WSN can be evaluated via classical reliability theory. Numerical results show the influence of parameters such as the true positive rate and the false positive rate on a sensor node's MTTF. Furthermore, we validate the method of reliability evaluation for a clustered WSN according to the number of sensor nodes in a cluster, the number of clusters in a route, and the number of routes in the WSN.

MULTIMODAL PERFORMANCE AND RELIABILITY ANALYSIS OF THE PIERRE AUGER OBSERVATORY NORTH SITE

The Pierre Auger Cosmic Ray Observatory North site employs a large array of surface detector stations (tanks) to detect the secondary particle showers generated by ultra-high energy cosmic rays. Due to the rare nature of ultra-high energy cosmic rays, it is important to have a high reliability on tank communications, ensuring no valuable data is lost. The Auger North site employs a peer-to-peer paradigm, the Wireless Architecture for Hard Real-Time Embedded Networks (WAHREN), designed specifically for highly reliable message delivery over fixed networks, under hard real-time deadlines. The WAHREN design included two retransmission protocols, Micro- and Macro- retransmission. To fully understand how each retransmission protocol increased the reliability of communications, this analysis evaluated the system without using either retransmission protocol (Case-0), both Micro- and Macro-retransmission individually (Micro and Macro), and Micro- and Macro-retransmission combined. This thesis used a multimodal modeling methodology to prove that a performance and reliability analysis of WAHREN was possible, and provided the results of the analysis. A multimodal approach was necessary because these processes were driven by different mathematical models. The results from this analysis can be used as a framework for making design decisions for the Auger North communication system.

WATER USE AND SYSTEM RELIABILITY UNDER DIESELGENERATOR AND SOLAR PHOTOVOLTAIC POWERED PUMPING SYSTEMS: A CASE STUDY OF SOLLA TOGO

Access to improved potable water sources is recognized as one of the key factors in improving health and alleviating global poverty. In recently years, substantial investments have been made internationally in potable water infrastructure projects, allowing 2.3 billion people to gain access to potable water from 1990-2012. One such project was planned and installed in Solla, Togo, a rural village in the northern part of the country, from 2010-2012. Ethnographic studies revealed that, while the community has access to potable water, an estimated 45% of the village’s 1500 residents still rely on unprotected sources for drinking and cooking. Additionally, inequality in system use based on income level was revealed, with the higher income groups accessing the system more regularly than lower income groups. Cost, as well as the availability of cheaper sources, was identified as the main deterrent from using the new water distribution system. A new water-pricing scheme is investigated here with the intention of making the system accessible to a greater percentage of the population. Since 2012, a village-level water committee has been responsible for operations and maintenance (O&M), fulfilling the community management model that is recommended by many development theorists in order to create sustainable projects. The water committee received post-construction support, mostly in the form of technical support during system breakdowns, from the Togolese Ministry of Water and Sanitation (MWSVH). While this support has been valuable in maintaining a functional water supply system in Solla, the water committee still has managerial challenges, particularly with billing and fee collection. As a result, the water committee has only received 2% - 25% of the fees owed at each private connection and public tap stand, making their finances vulnerable when future repairs and capital replacements are necessary. A new management structure is proposed by the MWSVH that will pay utilities workers a wage and will hire an accountant in order to improve the local management and increase revenue. This proposal is analyzed under the new water pricing schemes that are presented. Initially, the rural water supply system was powered by a diesel-generator, but in 2013, a solar photo-voltaic power supply was installed. The new system proved a fiscal improvement for the village water committee, since it drastically reduced their annual O&M costs. However, the new system pumps a smaller volume of water on a daily basis and did not meet the community’s water needs during the dry season of 2014. A hydraulic network model was developed to investigate the system’s reliability under diesel-generator (DGPS) and solar photovoltaic (PVPS) power supplies. Additionally, a new system layout is proposed for the PVPS that allows pumping directly into the distribution line, circumventing the high head associated with pumping solely to the storage tank. It was determined that this new layout would allow for a greater volume of water to be provided to the demand points over the course of a day, meeting a greater fraction of the demand than with the current layout.

The State of our Toolbox: A Meta-analysis of Reliability Measurement Precision

My study investigated internal consistency estimates of psychometric surveys as an operationalization of the state of measurement precision of constructs in industrial and organizational (I/O) psychology. Analyses were conducted of samples used in research articles published in the Journal of Applied Psychology between 1975 and 2010 in five year intervals (K = 934) from 480 articles yielding 1427 coefficients. Articles and their respective samples were coded for test-taker characteristics (e.g., age, gender, and ethnicity), research settings (e.g., lab and field studies), and actual tests (e.g., number of items and scale anchor points). A reliability and inter-item correlations depository was developed for I/O variables and construct groups. Personality measures had significantly lower inter-item correlations than other construct groups. Also, internal consistency estimates and reporting practices were evaluated over time, demonstrating an improvement in measurement precision and missing data.

Assessing the contribution of microgrids to the reliability of distribution networks

The emergence of microgeneration has recently lead to the concept of microgrid, a network of LV consumers and producers able to export electric energy in some circumstances and also to work in an isolated way in emergency situations. Research on the organization of microgrids, control devices, functionalities and other technical aspects is presently being carried out, in order to establish a consistent technical framework to support the concept. The successful development of the microgrid concept implies the definition of a suitable regulation for its integration on distribution systems. In order to define such a regulation, the identification of costs and benefits that microgrids may bring is a crucial task. Actually, this is the basis for a discussion about the way global costs could be divided among the different agents that benefit from the development of microgrids. Among other aspects, the effect of microgrids on the reliability of the distribution network has been pointed out as an important advantage, due to the ability of isolated operation in emergency situations. This paper identifies the situations where the existence of a microgrid may reduce the interruption rate and duration and thus improve the reliability indices of the distribution network. The relevant expressions necessary to quantify the reliability are presented. An illustrative example is included, where the global influence of the microgrid in the reliability is commented.