Empirical assessment of architecture-based reliability of open-source software

A number of analytical models have been proposed earlier for quantifying software reliability. Some of these models estimate the failure behavior of the software using black-box testing, which treats the software as a monolithic whole. With the evolution of component based software development, the necessity to use white-box testing increased. A few architecture-based reliability models, which use white-box approach, were proposed earlier and they have been validated using several small case studies and proved to be correct. However, there is a dearth of large-scale empirical data used for reliability analysis. This thesis enriches the empirical knowledge in software reliability engineering. We use a real, large-scale case study, GCC compiler, for our experiments. To the best of out knowledge, this is the most comprehensive case study ever used for software reliability analysis. The software is instrumented with a profiler, to extract the execution profiles of the test cases. The execution profiles form the basis for building the operational profile of the system, which describes the software usage. The test case failures are traced back to the faults in the source code to analyze the failure behavior of the components. These results are used to estimate the reliability of the software, as well as the uncertainty in the reliability analysis using entropy

Database Design for the Collection and Visualization of Sustainabilty Data

The goal of the project was to create a database that would be a repository for the high volume of sustainability data Illumina would like to collect. To couple with the database the project team’s goal was to design a system for visualizing the data graphically. Illumina required a database system that would be user-friendly, easy to add, delete, and edit data inputs, as well as a program that would allow the user to easily sort and graph data. The intent of the graphical representation of the data is to publish the graphs in a monthly report that would be circulated internally, as well as some graphs that would be published through public domains. A number of difficulties along the way led to some crucial design changes, including Microsoft Access being the only well-established program capable of meeting the project goals, and Microsoft Excel being the only system capable of creating dynamic graphs that can be easily exported

Three-year Performance of Acacia auriculiformis Provenances at Serdang, Malaysia

A trial consisting of 28 provenances ofAcacia auriculifonnis A. Cunn. ex Benth. was measured for survival and growth at 6, 12, 18, 24 and 36 months. Tree form was also assessed at 18 months. Of the provenances, 7 were from northern Queensland and 15 from Northern Territory, Australia, and 6 from Papua New Guinea. All provenances survived well (> 66%) but they differed significantly (P < 0.01) in their growth performance after 6 months. Half of the provenances tested had more than 50% of their trees with single stems. Queensland provenances generally grew faster than those from Northern Territory and Papua New Guinea. For timber production, four Queensland provenances (Archer River, Coen River, Wenlock River and Kings Plain), three Northern Territory provenances (Noogoo Swamp, Douglas River and E. Alligator River), and a Papua New Guinean provenance (Old Tonda Village) were identifzed as promising

High Power LDMOS technology for wireless infrastructure

The progress in wideband cellular systems was followed by the development of the necessary transistor technology. This contribution describes microwave LDMOS transistors used in RBS (Radio Base Station) amplifiers. We discuss the issues of the manufacturing process, packaging, reliability, RF performance and models necessary for successful devices for 3G systems at 2.1 - 2.2 GHz

Activation of Carbon Porous Paper for Alkaline Alcoholic Fuel Cells

In this study, various treatment methods to increase the reactivity of carbon porous electrodes for alkaline alcoholic fuel cells were investigated with commercially available carbon papers to understand the characteristic electrochemical behaviors of the treated carbon electrodes and to find the best method to enhance the cell performance. Effects of thermal treatment, potassium hydroxide (KOH) treatment, N2 doping, and reaction-area control via a multi-layered structure were compared in the cell-based tests, and a huge improvement in the cell performance (i.e., 64% increase of open circuit voltage (OCV) and 320% increase of max power density) was found from the thermal-treated four-layered carbon porous electrode. The results were compared with those from platinum on carbon (Pt/C)-based cells, and a discussion on the direction of research in the future was conducted. The results of this study are expected to provide key guidelines for alcoholic fuel cell (AFC) developers to develop cost-effective AFC with a carbon electrode

Investigation of pretreating methods to activate carbon electrode for alkaline alcohol fuel cell

Advisors: Kyu Taek Cho.Committee members: Pradip Majumdar; Donald Zinger.Includes bibliographical references.Includes illustrations.Alcoholic fuel cells have been developed intensively over decades for portable applications, but the full application was limited due to the issues such as high system cost, low performance, and durability. The main focus of this research is to replace the expensive platinum catalyst with cheap carbon material to solve one of key challenging issues, the system cost. Alkaline system was utilized, while most of related research has been conducted in acidic condition, due to benefits of fast kinetics, low alcohol/water crossover rate, and low cost of anion exchange membrane which is order of magnitude cheaper than Nafion membrane in acid system. Cheap and commercially available carbon papers were selected as an electrode for oxygen reduction reaction (ORR) in the positive side, and systematic research has been conducted to enhance the reactivity of ORR on carbon material. Various methods such as thermal, chemical, and vapor deposition were applied to activate the carbon material by controlling its surface area, wettability and functional groups such as oxygen and nitrogen at its surface. It was found that thermal treatment of carbon was more efficient in enhancing the cell performance than alkaline treatment and nitrogen doping method, and by increasing the surface area of thermally treated carbon, the cell performance was enhanced further. However, the cell performance is still lower than that of the cell catalyzed by platinum, but the performance is expected to be improved further by optimizing cell structures and operating conditions which will be the future work.M.S. (Master of Science

Genetic variation in growth and stem form characteristics in acacia auriculiformis

Significant differences (p < O.Ol) were found among 28 provenances of Acacia auriculiformis for height. diameter breast height (OBH). basal diameter and stem form. The average height of the provenances ranged from 6.6 to 10.4 m and OBH ranged from 5.6 to 9.6 cm. Low genetic parameters were recorded for all the characters indicating that only limited genetic improvement can be obtained by selecting any of the provenances for use at the location tested. OBH had the highest heritability estimation (0.46) and relatively high potential for genetic advance (expressed as a percentage of the mean. 18%) among the characters examined. Thus. OBH can be considered as a possible character to be used in selecting the A. auriculiformis provenances tested for advanced-generation improvement