On A Simpler and Faster Derivation of Single Use Reliability Mean and Variance for Model-Based Statistical Testing

Markov chain usage-based statistical testing has proved sound and effective in providing audit trails of evidence in certifying software-intensive systems. The system end-toend reliability is derived analytically in closed form, following an arc-based Bayesian model. System reliability is represented by an important statistic called single use reliability, and defined as the probability of a randomly selected use being successful. This paper continues our earlier work on a simpler and faster derivation of the single use reliability mean, and proposes a new derivation of the single use reliability variance by applying a well-known theorem and eliminating the need to compute the second moments of arc failure probabilities. Our new results complete a new analysis that could be shown to be simpler, faster, and more direct while also rendering a more intuitive explanation. Our new theory is illustrated with three simple Markov chain usage models with manual derivations and experimental results

Investigation of Downey model for speedup prediction

In parallel computing, accurate prediction of speedup is important for job schedulers with adaptive resource allocation. The predicted speedup determines the expected runtime on a certain number of nodes and the efficiency by which the resources are used. Among the existing speedup prediction models, the Downey model [5, 6] is simple but promising. However, the prediction accuracy of the Downey model needs to be investigated in realistic scenario setups. In this thesis, we use the NAS benchmarks and synthetic benchmarks [19] to generate scenarios in which the performance of the Downey model is examined. Based on these experiments, conditions are suggested for the successful application of the Downey model

Do Consumers Trust the National Inspection Exemption Brands? Evidence from Infant Formula in China

Consumers are often uncertain about product quality and have to rely on different information, either given or pursued, to assess quality. Developing countries may lack institutional and technical resources to rigorously monitor and enforce product quality standards and/or to implement market-based instruments where market failures are common. The information-based instruments on product quality may work well in these countries as they reduce information asymmetry between firms and consumers. This study investigates one particular information-based instrument, the National Inspection Exemption (NIE) system in China. China launched the National Inspection Exemption (NIE) System in various industries in 2000 to award firms who are in compliance with the quality standards, to inform consumers of product quality, and to lessen the pressure on regulatory monitoring and enforcement of product quality standards. Once a firm is granted the NIE title by China's National Administration of Quality Supervision, Inspection and Quarantine (AQSIQ), its products are exempted from quality inspections by all governmental agencies at different levels for three years; but it is obligated to report the product quality condition to the local AQSIQ office annually. The NIE titled firms are also allowed to include the title in the product label and to use the status in the advertisement campaign. Based on the theoretical framework, we establish the hypothesis that consumers are more willing to buy the product with the NIE title and the NIE title is likely to increase sales revenue when consumers lack of means to assess quality. The empirical application of China dairy industry supports the theoretical hypothesis. In particular, using the firm-level panel data, we find that the NIE title boots sales revenue and the impact is both statistically and economically significant based on the difference-in-difference estimate and the random-fixed effect estimations. Furthermore, using the survey data collected right after the 2008 China milk scandal regarding the brand choice of infant formula among 1,228 mothers with infants and young children, we find that consumers’ preference for the NIE title still present even the NIE titled firms are involved in a food scare event. The positive NIE preference is particularly strong among highly educated consumers and those who buy domestic brands.brand choice, food safety, product quality, national inspection exemption, quality standards, Food Consumption/Nutrition/Food Safety, Institutional and Behavioral Economics,