Cognitive diagnostic assessment (CDA) is a testing format that employs a cognitive model to, first, develop or identify items measuring specific knowledge and skills and, then, use this model to direct psychometric analyses of examinees item response patterns to promote diagnostic inferences. The attribute hierarchy method (AHM, Leighton, Gierl, & Hunka, 2004) is a psychometric procedure for classifying examinees test item responses into a set of structured attribute patterns associated with different components from a cognitive model of task performance. Attribute reliability is a fundamental concept in cognitive diagnostic assessment because it refers to the consistency of the decisions made in diagnostic test about examinees mastery of specific attributes. In this study, an adapted attribute-based reliability estimate was evaluated in comparison of the standard Cronbachs alpha using simulated data. Factors expected to influence attribute reliability estimates, including test length, sample size, model structure, and model-data fit level, were also studied. Results of this study revealed that the performances of the two attribute-based reliability estimation indices are comparable; however, the adapted index is conceptually more meaningful. Test length, model structure, and model-data fit were shown to impact attribute reliability estimates differentially. Implications to researchers and practitioners were given based on the simulation results. Limitations of the present study and future directions were also discussed. / Measurement, Evaluation, and Cognition

The Darlington simulator is now two decades old and, in common with any nuclear simulator of a similar age, suffers the problem of parts aging and obsolescence. In the past, replacement parts were available from the original vendor, Canadian Aviation Electronics. This is no longer an option, as the vendor has shown no interest in continuing to supply spare parts. Over the years, the Simulator Services Department has undertaken several projects. These projects were carried out aiming at different goals: (i) solving the problem with spare parts scarcity, (ii) modifying the simulator to adapt it to increased usage requirements, or (iii) upgrading the simulator to improve its reliability. One such project is the re-design of the Bus Interface Controller used in the I/O system of the simulator. The Bus Interface Controller is probably the most important piece of hardware in the whole I/O system. As such, it is important that reliability evaluation of the new design be carried out. Reliability has become increasingly important in the design of engineering systems. The key factor driving this is the demand of the customers [6]. The Darlington simulator usage time has always been consistently high, sometimes reaching the level of continuous use during some periods of the past years. The increase usage requirement creates a demand for higher availability, while the allocated maintenance time has been cut back substantially. The only way to meet this demand is to have better designs, where reliability consideration and evaluation are incorporated into the design cycle. Following this design methodology, during the early design cycle of the new Ethernet Bus Interface Controller, an analysis was done to evaluate its reliability. This report presents the details of the analysis and compares the reliability of the new design with the existing one. / UOIT

The epistemology of intuitions has become popular recently with philosophers’ increasing use of experimental methods to study intuitions. Philosophers have focused on the reliability of intuitions, as empirical studies seem to suggest that conflicting intuitions are common. One set of studies, concerning what Sinnott-Armstrong (2008) calls the abstract/concrete paradox, suggests that conflicting intuitions are common and, hence, that mistaken intuitions are common. As Goldman (2007) notes, if mistaken intuitions are sufficiently prevalent, then we might have reason to think intuitions are unreliable. I argue that mistaken intuitions are not common, since studies concerning the abstract/concrete paradox have unknowingly studied several distinct phenomena instead of the abstract/concrete paradox and, hence, that they present merely apparently conflicting intuitions. I then discuss the import of empirical studies for debates about reliability, noting that those studies can inform us about the unreliability of intuitions but we are still unclear about the conditions for reliability.

The objective of this study is to develop methodologies to estimate and predict the fragility of deteriorating reinforced concrete (RC) bridges, and to identify the effect of design and construction parameters on the reliability of RC bridges over time to assist in the design and construction process. To accurately estimate the fragility of deteriorating bridge, probabilistic capacity and demand models are developed. In addition, to simplify the calculation cost maintaining accuracy, fragility increment functions are developed. The proposed fragilities account for model uncertainties in the structural capacity, demand models, corrosion models. Furthermore, proper account is made of the uncertainties in the environmental conditions, material properties, and structural geometry. To identify the effect of design and construction parameters on the reliability of RC bridges, a sensitivity and importance analysis is conducted. Sensitivity analysis for an example bridge subject to corrosion is carried out to identify which parameters have the largest impact on the reliability over time. This dissertation considers different combinations of chloride exposure condition, environmental oxygen availability, water-to-cement ratios, and curing conditions, which affect the reliability of bridges over time. The developed models are applicable to both existing and new RC bridges and may be employed for the prediction of service-life and life-cycle cost analysis of RC bridges.

I used reliability generalization procedures to determine the mean score reliability of the Eating Disorder Inventory (EDI), the Eating Attitudes Test (EAT), and the Bulimia Test (BULIT). Reliability generalization is a type of meta-analysis used to examine the mean score reliability of a measure across studies and to explore study factors that influence mean score reliability. Score reliability estimates were included in 28.67% of 293 studies using the EDI, 36.28% of 215 studies using the EAT, and 41.46% of 41 studies utilizing the BULIT. For the EDI, mean Cronbach’s alphas for the subscales ranged from .52 to .89 and the mean estimate for the total score was .91. For the EAT-40 and EAT-26, mean estimates of internal consistency were .81 and .86 respectively. Mean estimates of internal consistency for the EAT-26 subscales ranged from .56 to .80. The mean estimate of internal consistency for the BULIT-R was .93. Overall, the mean reliability of scores on all three measures and their subscales/factors was acceptable except for the Asceticism subscale of the EDI and the Oral Control factor on the EAT-26, which had mean internal consistency estimates of .52 and .56 respectively. For the EDI, the majority of the subscales that measure specific eating disorder attitudes and behaviors, such as Bulimia and Perfectionism displayed higher score reliability in clinical eating disorder samples than in nonclinical samples. This difference was not found in the Drive for Thinness and Body Dissatisfaction subscales, perhaps because these attitudes are common in both eating disorder and nonclinical samples. Score reliability information for the EAT and BULIT was primarily reported for nonclinical samples; therefore, it is difficult to characterize the effect of type of sample on these measures. There was a tendency for mean score reliability for all the measures to be higher in the adult samples than in adolescent samples and in the female samples compared to the male samples. This study highlights the importance of assessing and reporting internal consistency every time a measure is used because reliability is affected by characteristics of the participants being examined.

Entry-time processes are finite-state continuous-time jump processes with transition rates depending only on the two states involved in transition, the calendar time, and the most recent arrival time, which is termed as entry-time. The entry-time processes have the potential to provide a significantly greater range of applicability and flexibility than traditional reliability tools for case studies related to equipment and components in nuclear power plants. In this dissertation, the finite difference approximation of the integrodifferential Chapman-Kolmogorov equations for the entry-time processes was developed, and then it was verified by application to some hypothetical examples that are solved by alternative means, either (semi-)analytically or via simulation. To demonstrate the ability of entry-time model to applications in nuclear power plants for a RIAM based scenario, the entry-time approach is applied to the maintenance of main generators in nuclear power using the data from INPO-EPIX database. In this application, both reliability and financial performances acquired using the entry-time approaches corresponding to different maintenance policies are presented and discussed to help make maintenance decisions for the plant management. The ability of the EPIX database to provide time-dependent failure rates is demonstrated and the techniques for extraction of failure rates from the database for main generators are also discussed.

The traditional displayer ¡V CRT has already been substituted by liquid crystal displayer (LCD).The a-Si TFT is used to be a switch, while the size of the displayer increases, the require of the performance and quality of TFTs is more and more better. Therefore, it is very important subject to study the stability and to improve the performance of a-Si TFTs. In this study, it simulated the process of the degradation on the TFTs by changing the sizes of TFTs and bias modes to find to stability mechanism of the TFTs. It can be known that under AC stress the degradation depends on the channel length, longer channel length with less degradation. In order to improve the traditional dual-gate structure TFTs, it had made dual-gate TFTs with ITO back-gate, the process of the new structure TFTs are fully compatible with the conventional BCE TFT fabrication process. With dual-channel conduction, the dual-gate TFTs exhibit higher on current and lower photo leakage current performance than the conventional inverted staggered TFTs In this study it also use the dual-gate structure to investigate how the back-channel influence the front-channel conduction. Apply DC bias on the back-gate to from defects at the interface of the active layer and passvation layer, it is found that after stress the on-current show almost the same quantities, and the photo leakage current is obvious decreased.

Liquid crystal display is the most valuable and universal produce of the electric monitor presently and it will into the stage of stable. In the future, the reliability is more important and also will be gradually the key point of index. Most of studies about the reliability of the back light module that concentrate on the thermal effect, there are seldom researches corresponding to the humidity and time effect. Therefore, we emphasize thermal, humidity and time factor for optical performance influence of the back light module in this thesis. We also used the experimental design of Taguchi method to determine the most important factor and development the basic for the reliability of the back light module. According to the result, the changing of the temperature influence the optical performance is the most.

The electric power utility industry is presently undergoing a change towards the deregulated environment. This has resulted in unbundling of generation, transmission and distribution services. The introduction of competition into unbundled electricity services may lead system operation closer to its security boundaries resulting in smaller operating safety margins. The competitive environment is expected to lead to lower price rates for customers and higher efficiency for power suppliers in the long run. Under this deregulated environment, security assessment and pricing of transmission services have become important issues in power systems. This dissertation provides new methods for power system security assessment and transmission pricing. In power system security assessment, the following issues are discussed 1) The description of probabilistic methods for power system security assessment 2) The computation time of simulation methods 3) on-line security assessment for operation. A probabilistic method using Monte-Carlo simulation is proposed for power system security assessment. This method takes into account dynamic and static effects corresponding to contingencies. Two different Kohonen networks, Self-Organizing Maps and Learning Vector Quantization, are employed to speed up the probabilistic method. The combination of Kohonen networks and Monte-Carlo simulation can reduce computation time in comparison with straight Monte-Carlo simulation. A technique for security assessment employing Bayes classifier is also proposed. This method can be useful for system operators to make security decisions during on-line power system operation. This dissertation also suggests an approach for allocating transmission transaction costs based on reliability benefits in transmission services. The proposed method shows the transmission transaction cost of reliability benefits when transmission line capacities are considered. The ratio between allocation by transmission line capacity-use and allocation by reliability benefits is computed using the probability of system failure.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Donald R. Eaton, Kenneth, H. Doerr. Includes bibliographical references (p. 67-69). Also available online.