On the notion of granularity

Granularity is a well known concept in parallel processing. While intuitively, the distinction between coarse-grain and fine-grain paralellism is clear, there is no rigorous definition. This paper develops two notions of granularity, each defined formally and represented by a single rational number. The two notions are compared and contrasted with each other and with previously proposed definitions of granularity.Supported, in part, by NSA OCREAE Grant MDA904-85-H-0002. Currently on leave at the National Science Foundation.     

The role of modelling in identifying drug targets for diseases of the cell cycle.

The cell cycle is implicated in diseases that are the leading cause of mortality and morbidity in the developed world. Until recently, the search for drug targets has focused on relatively small parts of the regulatory network under the assumption that key events can be controlled by targeting single pathways. This is valid provided the impact of couplings to the wider scale context of the network can be ignored. The resulting depth of study has revealed many new insights; however, these have been won at the expense of breadth and a proper understanding of the consequences of links between the different parts of the network. Since it is now becoming clear that these early assumptions may not hold and successful treatments are likely to employ drugs that simultaneously target a number of different sites in the regulatory network, it is timely to redress this imbalance. However, the substantial increase in complexity presents new challenges and necessitates parallel theoretical and experimental approaches. We review the current status of theoretical models for the cell cycle in light of these new challenges. Many of the existing approaches are not sufficiently comprehensive to simultaneously incorporate the required extent of couplings. Where more appropriate levels of complexity are incorporated, the models are difficult to link directly to currently available data. Further progress requires a better integration of experiment and theory. New kinds of data are required that are quantitative, have a higher temporal resolution and that allow simultaneous quantitative comparison of the concentration of larger numbers of different proteins. More comprehensive models are required and must accommodate not only substantial uncertainties in the structure and kinetic parameters of the networks, but also high levels of ignorance. The most recent results relating network complexity to robustness of the dynamics provide clues that suggest progress is possible.     

Feedback transformations on tori

Here we investigate the problem of transforming a nonlinear system on the torusT ⁿ by using global feedback and global changes of coordinates into an invariant system (i.e., a control system of whichf andg _i are (left and right) invariant vector fields whenT ² is considered as a Lie group). We provide a complete answer whenn=2 and give a sufficient condition and necessary conditions in the more general case.     

Finding large 3-free sets I: The small n case

There has been much work on the following question: given n, how large can a subset of $\{1,\dots ,n\}$ be that has no arithmetic progressions of length 3. We call such sets 3-free. Most of the work has been asymptotic. In this paper we sketch applications of large 3-free sets, present techniques to find large 3-free sets of $\{1,\dots ,n\}$ for $n?250$, and give empirical results obtained by coding up those techniques. In the sequel we survey the known techniques for finding large 3-free sets of $\{1,\dots ,n\}$ for large n, discuss variants of them, and give empirical results obtained by coding up those techniques and variants.     

Starting open source collaborative innovation: the antecedents of network formation in community source

Specific needs in the area of enterprise applications have led to a new type of collaborative open source innovation development across institution borders: community source. We use the Kuali community source network, a jointly managed, border‐spanning organization that supplies the institutions that created it, to describe how community source works. This study builds a theoretical basis for understanding the individual and institutional factors affecting community source network formation and the decision by organizations to join a community source network. We identify eight antecedents of decisions about forming or joining community source initiatives: motives, learning, trust, norms and monitoring, institutional similarity, external funding, hostile external environment and information technology. © 2016 John Wiley & Sons Ltd     

An elusive antecedent of superior firm performance: The knowledge management factor

Knowledge management (KM) concepts, principles, and technologies provide a foundation for understanding and building systems for acquiring, assimilating, selecting, generating, and emitting knowledge—a crucial resource of the firm. In the knowledge management community, it is commonly contended that knowledge, and capabilities for processing it, comprise a major resource that can differentiate one firm from another in the sense of yielding better performance or a competitive edge. However, aside from anecdotes, there has been little to substantiate this contention. Can any empirical link be discovered between a firm's KM success and that firm's financial performance? To develop an answer to this question, we use an independent research company's reports of firms judged to be highly successful in their KM initiatives, plus related data reported by COMPUSTAT. As an initial investigation of the linkage between KM performance and firm performance, as measured by financial ratios, this study uses the Matched Sample Comparison Group methodology to evaluate research hypotheses. The analysis reveals a heretofore elusive antecedent of firm performance—evidence that superior KM performance is indeed a predictor of superior bottom-line performance. This study contributes to the information systems (IS) literature by demonstrating that KM, a basic foundation for IS, is an important factor to consider from the standpoint of achieving strong financial performance. As such, it suggests that KM furnishes an important context for understanding designs, applications, and possibilities for IS with respect to achieving such performance. In the context of devising and executing KM initiatives, both technological and human treatments of knowledge need to be cultivated and integrated in ways that lead to superior KM performance. This study also contributes to the management literature by going beyond anecdotes and case studies in buttressing the proposition that a firm's KM competencies are an important ingredient in that firm's performance. It solidifies the raison d'etre for investigating KM phenomena and methods (computer-based and human), both within and across modern organizations. It gives practicing managers evidence that bottom-line benefits are indeed associated with superior KM strategy and execution.     

Organized knowledge sharing with book-centered Web sites: An architecture, implementation and analysis

For educators, the World Wide Web offers a valuable technology for knowledge sharing. It can complement more traditional approaches to knowledge sharing such as books and lectures. Here, we identify and differentiate three major approaches for Web-based knowledge sharing: course-centered sites, subject-centered sites, and book-centered sites. A rationale for book-centered sites, those developed to facilitate students’ and instructors’ efforts in courses that use the book, is advanced. We introduce an architecture of features that can guide developers of such sites. This is illustrated by a book-centered site implemented according to the architecture. Several sites for introductory business computing books are compared and contrasted in terms of the architecture, suggesting ways in which each can be extended. This revised version was published online in July 2006 with corrections to the Cover Date.     

Preparation of octacalcium phosphate by the hydrolysis of α-tricalcium phosphate

A new simple method of preparation for the thermodynamically unstable octacalcium phosphate [Ca₈H₂(PO₄)₆·5H₂O; OCP] has been developed using the hydrolysis of -Ca₃(PO₄)₂ instead of the conventional hydrolysis of CaHPO₄·2H₂O. The hydrolysis experiments were carried out by treating an -Ca₃(PO₄)₂(1 g)-H₂O(50 m) suspension for 3 h at temperatures in the range 40 to 80° C and at pHs in the range 3 to 7.5. The formation of OCR was limited to within a narrow region between formation regions of other phosphates. Favourable conditions for OCP preparation were, for example, 70° C, pH4.5 to 5.0 and 60° C, pH5.0. Particles of OCP were composed of tight aggregates of strip-like microcrystals growing probably along the [0 0 1] and (1 0 0) plane of the OCP structure. Nearly stoichiometric OCP was obtained under the most suitable conditions with good reproducibility. Pyrolytic processes of OCP were approximately consistent with the data published so far. However, the temperatures of the appearance and disappearance of pyrolytic crystalline phases and ionic species deviated slightly from the published data. Thermal dehydration up to 150° C without destruction of OCP and decomposition reactions above 300° C resulted in changes in surface area and average pore radius of OCP.     

Considering Prework on Industrial Projects

Prefabrication, preassembly, modularization, and off-site fabrication, collectively termed as prework have become more viable with recent advances in design and information technologies. These construction methods offer a substantial opportunity to improve project performance when circumstances merit. Successful implementation of these methods on a particular project requires systematic analysis and early decision making based on specific factors of the project. This paper identifies those factors influencing decisions on the use of prework, and current industry practices for evaluating the applicability of prework on industrial projects. It then presents a decision framework to assist industry practitioners with evaluating the applicability of prework on their project, and describes a computerized tool to aid project teams in the decision-making process. The developed framework and tool are useful and effective in the decision-making process, and easy to use, as validated by practitioners in the industry.     

Imaginal and emotional experiences in pleasure-oriented IT usage: A hedonic consumption perspective

Based on the marketing theory of hedonic consumption, this study examines the effects of six types of imaginal and emotional experiences on using pleasure-oriented IT. Associated hypotheses are tested using questionnaire responses from 443 online game players. The results provide strong support for the major hypotheses and indicate that the determinants of behavior may differ in using pleasure-oriented versus productivity-oriented IT. This paper contributes not only to the application of a marketing theory to IS research, but also to improved understanding of using pleasure-oriented IT and of why people use technologies that are not particularly useful from a productivity standpoint.