Of all merits of the object-oriented paradigm, flexibility is probably the most important in a world of constantly changing requirements and the most striking difference compared to previous approaches. However, it is rather difficult to quantify this aspect of quality: This paper describes a probabilistic approach to estimate the change proneness of an object-oriented design by evaluating the probability that each class of the system will be affected when new functionality is added or when existing functionality is modified. It is obvious that when a system exhibits a large sensitivity to changes, the corresponding design quality is questionable. The extracted probabilities of change can be used to assist maintenance and to observe the evolution of stability through successive generations and identify a possible “saturation ” level beyond which any attempt to improve the design without major refactoring is impossible. The proposed model has been evaluated on two multiversion open source projects. The process has been fully automated by a Java program, while statistical analysis has proved improved correlation between the extracted probabilities and actual changes in each of the classes in comparison to a prediction model that relies simply on past data.

Balancing comfort: Occupants' control of window blinds in private offices by Vorapat Inkarojrit Doctor of Philosophy in Architecture University of California, Berkeley Professor Charles C. Benton, Chair The goal of this study was to develop predictive models of window blind control that could be used as a function in energy simulation programs and provide the basis for the development of future automated shading systems. Toward this goal, a two-part study, consisting of a window blind usage survey and a field study, was conducted in Berkeley, California, USA, during a period spanning from the vernal equinox to window solstice. A total of one hundred and thirteen office building occupants participated in the survey. Twenty-five occupants participated in the field study, in which measurements of physical environmental conditions were cross-linked to the participants' assessment of visual and thermal comfort sensations. Results from the survey showed that the primary window blind closing reason was to reduce glare from sunlight and bright windows. For the field study, a total of thirteen predictive window blind control logistic models were derived using the Generalized Estimating Equations (GEE) technique. TABLE OF CONTENTS TABLE OF CONTENTS........................................................................................... i LIST OF FIGURES................................................................................................... v LIST OF TABLES..................................................................................................... xi ACKNOWLEDGEMENTS.......................................................................................xiii CHAPTER 1:

This exploratory study examines civic engagement with e-government via Web sites. It provides an analytical framework that integrates both the supply and the demand sides of citizen interaction with e-government. In modeling three dimensions of online civic engagement (government information access, service transactions, and contributing to government policy-making processes), the study framework incorporates a number of variables, including political activism, civic involvement, perceived benefits and difficulties, information channels, and demographic characteristics. Based on a national sample of Internet users, the study highlights the importance of the supply side (availability of e-government) for promoting civic engagement. Furthermore, political activism is found to be related positively to accessing government policy information and contributing to policy-making processes. The study results also confirm the significant impact of perceived benefits in fostering online civic engagement. Future research can benefit from this study by utilizing a more comprehensive model, treating various dimensions of online engagement separately, and conducting an in-depth analysis of the elements of perceived benefits.

the staff at ACTION, especially Bill Yoshimoto and Mary Beth Hash, for their considerable support and assistance. Lou Barrett, Claudia Canales, Josh Rowlett, David Singleton, and Patrick Warner, all current or past members of the ACTION team, were extremely helpful throughout the study and uniformly accommodated our many requests for assistance. Ed Zedlewski and Maggie Heisler, with the National Institute of Justice, provided guidance and insights that greatly improved the project’s design and execution, and Sandy Woerle helped guide us through the final stages of the project. Joe Donnermeyer offered many helpful ideas for improving the research design. We give special thanks to the many farmers who participated in the study, without whom there would not have been anything to report. John Roman and Aaron Chalfin were primarily responsible for the cost-benefit analysis discussions, which are detailed

*Order of authorship is alphabetical to denote equal contribution. Direct correspondence to Kraig

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This paper studies the diffusion of SuggestBot, an intelligent task recommendation system that helps people find articles to edit in Wikipedia. We investigate factors that predict who adopts SuggestBot and its impact on adopters ’ future contributions to this online community. Analyzing records of participants ’ activities in Wikipedia, we found that both individual characteristics and social ties influence adoption. Specially, we found that highly involved contributors were more likely to adopt SuggestBot; interpersonal exposure to innovation, cohesion, and tie homophily all substantially increased the likelihood of adoption. However, connections to prominent, high-status contributors did not influence adoption. Finally, although the SuggestBot innovation saw limited distribution, adopters made significantly more contributions to Wikipedia after adoption than nonadopter counterparts in the comparison group. Key words: diffusion of innovation, social network, tie cohesion, tie homophily, on-line community. doi:10.1111/j.1083-6101.2009.01491.x All communities, online and off, seek to motivate members to participate and continue contributing to the betterment of the group (Kanter, 1972; Olson, 1965). Whether posting messages, welcoming newcomers, building information databases, or helping to administrate the group’s policy, online communities need member contributions to survive 1. This is a serious problem for both new and existing communities because many face the challenge of undercontribution and/or inactivity

The goal of this report was to test the use of sensor-based skill measures in evaluating performance differences in rifle marksmanship. Ten shots were collected from 30 novices and 9 experts. Three measures for breath control and one for trigger control were used to predict skill classification. The data were fitted with a logistic regression model using holdout validation to assess the quality of model classifications. Individually, all four measures were significant; when considered together, only three measures were significant predictors for level of expertise (p <.05). Overall percent correct in shot classification for the testing data was 90.0%, with a sensitivity of 67.5%, and 96.0% specificity.

The present study explores L1-Spanish speakers ’ learning of the English /i/–/� / contrast via acoustic analysis of vowel productions and perception of synthetic stimuli. L1-English, L1-Spanish, and L2-Spanish perception and production are also explored. The vowels examined are English /i/, /�/, adjacent English /e/, /�/, and Spanish /i/, /ei/, /e/. The acoustic properties examined are vowel duration, and initial and final first- and second-formant values. Diphthongisation / vowel inherent spectral change (VISC) is an important factor in the perception of /� / in the Canadian English dialect examined. Consistent with current theories that L1 and L2 learners build speech sound categories on the basis of the statistical distribution of acoustic properties, discriminant analysis and logistic regression are used to build models of production and perception data. Models trained on monolingual Spanish data predict that Spanish listeners just beginning to learn English will perceive most instances of English /i / as Spanish /i/, and most instances of English /� / as Spanish /e/; hence English /i/ and /� / will be easily distinguished. However, cross-sectional and longitudinal data from L1-Spanish learners of English suggest that they confuse English /i / and /�/, and begin to

Robert Faris is a doctoral student in sociology and a research associate in the Center for Community Capitalism.