Analyzing imbalance among homogeneous index servers in a web search system

The performance of parallel query processing in a cluster of index servers is crucial for modern web search systems. In such a scenario, the response time basically depends on the execution time of the slowest server to generate a partial ranked answer. Previous approaches investigate performance issues in this context using simulation, analytical modeling, experimentation, or a combination of them. Nevertheless, these approaches simply assume balanced execution times among homogeneous servers (by uniformly distributing the document collection among them, for instance)—a scenario that we did not observe in our experimentation. On the contrary, we found that even with a balanced distribution of the document collection among index servers, correlations between the frequency of a term in the query log and the size of its corresponding inverted list lead to imbalances in query execution times at these same servers, because these correlations affect disk caching behavior. Further, the relative sizes of the main memory at each server (with regard to disk space usage) and the number of servers participating in the parallel query processing also affect imbalance of local query execution times. These are relevant findings that have not been reported before and that, we understand, are of interest to the research community.     

Copyright or copyleft?: An analysis of property regimes for software development

Two property regimes for software development may be distinguished. Within corporations, on the one hand, a Private Regime obtains which excludes all outsiders from access to a firm's software assets. It is shown how the protective instruments of secrecy and both copyright and patent have been strengthened considerably during the last two decades. On the other, a Public Regime among hackers may be distinguished, initiated by individuals, organizations or firms, in which source code is freely exchanged. It is argued that copyright is put to novel use here: claiming their rights, authors write ‘open source licenses’ that allow public usage of the code, while at the same time regulating the inclusion of users. A ‘regulated commons’ is created. The analysis focuses successively on the most important open source licenses to emerge, the problem of possible incompatibility between them (especially as far as the dominant General Public License is concerned), and the fragmentation into several user communities that may result.     

Opportunity knocks

Research on technological opportunity has typically focused on the impact of broad industry characteristics on R&D intensity of firms. This study complements such approaches by examining the impact of a multidimensional vector that measures technological opportunity on independent inventors’ decisions to patent and commercialize inventions. Using data from 559 inventions and controlling for demand, appropriability, and competitive conditions, we found two of four tested dimensions of technological opportunity - technical performance and technical uncertainty - to be significant and important determinants of the likelihood of commercialization. Technical feasibility appears important in affecting patenting but unimportant in affecting commercialization. Technical significance carries a negative, although insignificant, sign conditioning commercialization.     

Infant joint attention, temperament, and social competence in preschool children

Infant joint attention has been observed to be related to social-emotional outcomes in at-risk children. To address whether this relation is also evident in typically developing children, 52 children were tested at 12, 15, 24, and 30 months to examine associations between infant joint attention and social outcomes. Twelve-month initiating and responding to joint attention were related to 30-month social competence and externalizing behavior, even when accounting for 15-month temperament ratings, 24-month cognition and language, and demographic variables. These results suggest that, in addition to associations with language and cognition, infant joint attention reflects robust aspects of development that are related to individual differences in the emergence of social and behavioral competence in childhood.     

Engaging adolescents with LD in higher order thinking about history concepts using integrated content enhancement routines

The understanding and use of historical concepts specified in national history standards pose many challenges to students. These challenges include both the acquisition of content knowledge and the use of that knowledge in ways that require higher order thinking. All students, including adolescents with learning disabilities (LD), are expected to understand and use concepts of history to pass high-stakes assessments and to participate meaningfully in a democratic society. This article describes Content Enhancement Routines (CERs) to illustrate instructional planning, teaching, and assessing for higher order thinking with examples from an American history unit. Research on the individual components of Content Enhancement Routines will be illustrated with data from 1 of the routines. The potential use of integrated sets of materials and procedures across grade levels and content areas will be discussed.     

Religious Development in African American Adolescents: Growth Patterns That Offer Protection

Although religiosity promotes resilient outcomes in African American (AA) adolescents, there is a lack of research that examines the protective role of religious development in the context of stressful life events (SLEs). In 1,595 AA adolescents, a cohort-sequential design was used from ages 12 to 18 to examine subtypes of religiosity, as well as distinct developmental patterns within subtypes. The protective role of religious development was also examined in the context of SLEs. The study findings indicated two subtypes of religiosity—extrinsic and intrinsic religiosity—as well as low and high developmental patterns in the identified subtypes. Furthermore, the protective influence of extrinsic and intrinsic religiosity gradually diminished from age 12 to 18 in the context of SLEs.     

Scoring Stability in a Large‐Scale Assessment Program: A Longitudinal Analysis of Leniency/Severity Effects

Although much attention has been given to rater effects in rater‐mediated assessment contexts, little research has examined the overall stability of leniency and severity effects over time. This study examined longitudinal scoring data collected during three consecutive administrations of a large‐scale, multi‐state summative assessment program. Multilevel models were used to assess the overall extent of rater leniency/severity during scoring and examine the extent to which leniency/severity effects were stable across the three administrations. Model results were then applied to scaled scores to estimate the impact of the stability of leniency/severity effects on students’ scores. Results showed relative scoring stability across administrations in mathematics. In English language arts, short constructed response items showed evidence of slightly increasing severity across administrations, while essays showed mixed results: evidence of both slightly increasing severity and moderately increasing leniency over time, depending on trait. However, when model results were applied to scaled scores, results revealed rater effects had minimal impact on students’ scores.     

Pedagogy and Curricular Choice in Community College Accelerated Writing Courses

To improve students’ outcomes and retention rates, community colleges have implemented acceleration strategies which hasten the completion of educational requirements (Edgecombe, 2011). The objective of this study was to investigate the effects of an accelerated freshmen writing course on teachers’ curricular decisions and pedagogical practices at a large urban community college. We conducted semi-structured interviews with the 11 faculty members teaching different sections of this accelerated writing course. All interviews were audiotaped, transcribed, coded, and analyzed. Our findings reveal that while instructors embrace the structural changes that come with accelerated courses and demonstrate a new appreciation for struggling students in their traditional English 101 class, they report on significant challenges in teaching due to the students’ lack of academic and personal maturity, as well as a need to lower their expectations and simplify the curriculum. This research raises questions about the unintended positive and negative effects of accelerated courses on teaching. More qualitative research is needed that focuses on the teachers’ experiences and their capacity to help students benefit from an accelerated course.     

Integration or Separation? Addressing Religious and Spiritual Issues in Multicultural Counseling: A National Survey of College Counselors

Given contemporary ethical concerns, the authors conducted a national survey of 216 college counselors’ perceptions of integrating religious and spiritual issues in multicultural counseling and counselor education. Using cluster analysis, the authors identified 4 patterns of commitments to multiculturalism and religiosity. Respondents demonstrated ethical bracketing in that they considered religious and spiritual issues favorably within the framework of multicultural counseling, irrespective of their commitments to those topics. Counselors can openly address spiritual and religious diversity.     

Attachment,Communication, and Relationship Functioning Among College Student Veterans and Nonveterans

This study examined attachment processes of college student veterans and nonveterans and further examined how veteran status and attachment style directly and indirectly predict relationship functioning. Results indicated that student veterans were more often dismissing in their attachment style but less often preoccupied than nonveteran students. Veteran status moderated the association between attachment style and dyadic consensus. The contributions of attachment and communication processes to overall relationship adjustment differed for student veterans and nonveterans.