Home About us Contact
|
Home About us Contact | ||
|
|
||
Formal Description (formal + description)
Selected AbstractsA reference model for grid architectures and its validationCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2010Wil van der Aalst Abstract Computing and data-intensive applications in physics, medicine, biology, graphics, and business intelligence require large and distributed infrastructures to address the challenges of the present and the future. For example, process mining applications are faced with terrabytes of event data and computationally expensive algorithms. Computer grids are increasingly being used to deal with such challenges. However, grid computing is often approached in an ad hoc and engineering-like manner. Despite the availability of many software packages for grid applications, a good conceptual model of the grid is missing. This paper provides a formal description of the grid in terms of a colored Petri net (CPN). This CPN can be seen as a reference model for grids as it clarifies the basic concepts at the conceptual level. Moreover, the CPN allows for various kinds of analyses ranging from verification to performance analysis. We validate our model based on real-life experiments using a testbed grid architecture available in our group and we show how the model can be used for the estimation of throughput times for scientific workflows. Copyright © 2009 John Wiley & Sons, Ltd. [source] INCIPIENT EVOLUTION OF WOLBACHIA COMPATIBILITY TYPESEVOLUTION, Issue 9 2004Sylvain Charlat Abstract . -Cytoplasmic incompatibility (CI) is induced in arthropods by the maternally inherited bacterium Wolbachia. When infected males mate with uninfected females or with females bearing a different Wolbachia variant, paternal chromosomes behave abnormally and embryos die. This pattern can be interpreted as resulting from two bacterial effects: One (usually termed mod, for modification) would affect sperm and induce embryo death, unless Wolbachia is also present in the egg, which implies the existence of a second effect, usually termed resc, for rescue. The fact that CI can occur in crosses between males and females infected by different Wolbachia shows that mod and resc interact in a specific manner. In other words, different compatibility types, or mod/resc pairs seem to have diverged from one (or a few) common ancestor(s). We are interested in the process allowing the evolution of mod/resc pairs. Here this question is addressed experimentally after cytoplasmic injection into a single host species (Drosophila simulans) by investigating compatibility relationships between closely related Wolbachia variants naturally evolving in different dipteran hosts: D. simulans, Drosophila melanogaster, and Rhagoletis cerasi. Our results suggest that closely related bacteria can be totally or partially incompatible. The compatibility relationships observed can be explained using a formal description of the mod and resc functions, implying both qualitative and quantitative variations. [source] Thrombocytopenia due to hypotension unrelated to infection: shock marrowINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2005T. A. Naqvi Summary Although peripheral blood cytopenias are observed in clinical practice following hypotensive episodes unrelated to infection, there has previously been no formal description of this in the medical literature. We retrospectively reviewed all medical intensive care unit records from two hospitals over a 5-year period to identify cases in which sustained hypotension had occurred that was unrelated to infection. After initial review, 10 records were identified that met our criteria (systolic blood pressure <90 mmHg for at least 6 h, with no evidence of sepsis or use of drugs commonly associated with suppression of haematopoiesis). All 10 of these patients were found to develop thrombocytopenia. The degree of thrombocytopenia correlated with the severity and duration of hypotension. Severe thrombocytopenia appeared to be associated with a poor outcome. Thrombocytopenia following shock unrelated to sepsis is common and is presumably related to hypoxic injury to haematopoietic progenitor cells. [source] Formalizing context-based reasoning: A modeling paradigm for representing tactical human behaviorINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 7 2008Avelino J. Gonzalez This paper formally describes the context-based reasoning (CxBR) paradigm. CxBR can be used to represent tactical human behavior in simulations or in the real world. In problem solving, the context can be said to inherently contain much knowledge about the situation in which the problem is to be solved and/or the environment in which it must be solved. This paper discusses some of the issues involved in a context-driven representation of human behavior and introduces a formal description of CxBR. © 2008 Wiley Periodicals, Inc. [source] Formal specification of SNMPv3 entities using action semanticsINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2004Elias P. Duarte Jr. This work presents a formal description of the structure and behaviour of SNMPv3 entities. IETF documents describe the semantics of the Simple Network Management Protocol version 3 in an almost completely informal way. Our formal description is given using action semantics, a completely formal yet verbose framework for the specification of programming concepts. The purpose of our description is to specify management entities without ambiguities, contributing to a better understanding of the NMPv3 framework that may lead to automatic implementation and verification of agents and manager applications.,Copyright © 2004 John Wiley & Sons, Ltd. [source] Pleomorphic hyalinizing angiectactic tumor of the buccal mucosaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2004Fumio Ide Pleomorphic hyalinizing angiectactic tumor (PHAT) of soft parts is a recently defined mesenchymal tumor of uncertain differentiation, with only a limited number of examples reported to date. We present a case of PHAT of the buccal mucosa in an 86-year-old woman. To our knowledge, there is no formal description of this tumor in the oral cavity. [source] Visually directed high-intensity focused ultrasound for organ-confined prostate cancer: a proposed standard for the conduct of therapyBJU INTERNATIONAL, Issue 6 2006Rowland O. Illing OBJECTIVE To propose a standard for the conduct of visually directed transrectal high-intensity focused ultrasound (HIFU) and to offer a formal description of the changes observed on B-mode ultrasonography (US) during this procedure. We describe our early experience of using two different treatment methods; algorithm-based HIFU and visually directed HIFU for the treatment of organ-confined prostate cancer. PATIENTS AND METHODS Between November 2004 and October 2005, 34 men were treated using the Sonablate®-500 (Focus Surgery, Indianapolis, IN, USA) as primary therapy for T1 or T2 prostate cancer. None had had previous hormone therapy and all had ,,3-month PSA nadirs recorded at the follow-up. Nine men were treated using an algorithm-based protocol (group 1) and 25 using visually directed therapy (group 2). The conduct of visually directed treatment was described and changes seen using B-mode US were categorized using three ,Uchida' grades. RESULTS The mean PSA nadir achieved in group 2 was 0.15 ng/mL, vs 1.51 ng/mL in group 1 (P < 0.005). In group 2, 21 of 25 men achieved PSA nadirs of ,,0.2 ng/mL 3 months after treatment. Seven men achieved undetectable PSA values. The occurrence rate of treatment-related toxicity was similar in both groups. CONCLUSION Visually directed, transrectal HIFU enables clinically important and statistically significantly lower PSA nadirs to be achieved than algorithm-based HIFU. This is the first reported experience of visually directed HIFU for the treatment of organ-confined prostate cancer. We think that this is the first attempt to standardize the conduct of therapy; such standardization facilitates teaching it, and makes it possible to derive quality standards. The standardization of the conduct of therapy is a key step in the process of health technology assessment. [source] Taxonomical, nomenclatural and biogeographical revelations in the Zamia skinneri complex of Central America (Cycadales: Zamiaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2008ALBERTO S. TAYLOR B. Evidence is provided substantiating (1) a more taxonomically sound application of the name Zamia skinneri Warsz. ex A.Dietr. to populations of green-emergent, plicate-leaved plants from coastal mainland Bocas del Toro, Panama and (2) the lack of a formal name for the red-emergent, plicate-leaved plants from north-central Panama. Re-characterization of Z. skinneri is followed by a discussion of the status of Z. neurophyllidia D.W.Stev. and formal descriptions of three endemic, arborescent, plicate-leaved cycads from northwestern and central Atlantic Panama: Z. hamannii sp. nov., Z. imperialis sp. nov. and Z. nesophila sp. nov. Also included is a brief discussion of taxonomic relationships within the group, a key to the plicate-leaved cycads of Panama and a hypothesis for the historical biogeography and evolution of the skinneri complex. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 399,429. [source] | ||||||||||||||||