80 research outputs found

    DiPerF: an automated DIstributed PERformance testing Framework

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    We present DiPerF, a distributed performance testing framework, aimed at simplifying and automating service performance evaluation. DiPerF coordinates a pool of machines that test a target service, collects and aggregates performance metrics, and generates performance statistics. The aggregate data collected provide information on service throughput, on service "fairness" when serving multiple clients concurrently, and on the impact of network latency on service performance. Furthermore, using this data, it is possible to build predictive models that estimate a service performance given the service load. We have tested DiPerF on 100+ machines on two testbeds, Grid3 and PlanetLab, and explored the performance of job submission services (pre WS GRAM and WS GRAM) included with Globus Toolkit 3.2.Comment: 8 pages, 8 figures, will appear in IEEE/ACM Grid2004, November 200

    Spectral Analysis of Traffic Functions in Urban Areas

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    The paper is focused on the Fourier transform application in urban traffic analysis and the use of said transform in traffic decomposition. The traffic function is defined as traffic flow generated by different categories of traffic participants. A Fourier analysis was elaborated in terms of identifying the main traffic function components, called traffic sub-functions. This paper presents the results of the method being applied in a real case situation, that is, an intersection in the city of Bucharest where the effect of a bus line was analysed. The analysis was done using different time scales, while three different traffic functions were defined to demonstrate the theoretical effect of the proposed method of analysis. An extension of the method is proposed to be applied in urban areas, especially in the areas covered by predictive traffic control.</p

    Meta-F*: Proof Automation with SMT, Tactics, and Metaprograms

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    We introduce Meta-F*, a tactics and metaprogramming framework for the F* program verifier. The main novelty of Meta-F* is allowing the use of tactics and metaprogramming to discharge assertions not solvable by SMT, or to just simplify them into well-behaved SMT fragments. Plus, Meta-F* can be used to generate verified code automatically. Meta-F* is implemented as an F* effect, which, given the powerful effect system of F*, heavily increases code reuse and even enables the lightweight verification of metaprograms. Metaprograms can be either interpreted, or compiled to efficient native code that can be dynamically loaded into the F* type-checker and can interoperate with interpreted code. Evaluation on realistic case studies shows that Meta-F* provides substantial gains in proof development, efficiency, and robustness.Comment: Full version of ESOP'19 pape

    Towards ServMark, an Architecture for Testing Grid Services

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    Technical University of Delft - Technical Report ServMark-2006-002, July 2006Grid computing provides a natural way to aggregate resources from different administrative domains for building large scale distributed environments. The Web Services paradigm proposes a way by which virtual services can be seamlessly integrated into global-scale solutions to complex problems. While the usage of Grid technology ranges from academia and research to business world and production, two issues must be considered: that the promised functionality can be accurately quantified and that the performance can be evaluated based on well defined means. Without adequate functionality demonstrators, systems cannot be tuned or adequately configured, and Web services cannot be stressed adequately in production environment. Without performance evaluation systems, the system design and procurement processes are limp, and the performance of Web Services in production cannot be assessed. In this paper, we present ServMark, a carefully researched tool for Grid performance evaluation. While we acknowledge that a lot of ground must be covered to fulfill the requirements of a system for testing Grid environments, and Web (and Grid) Services, we believe that ServMark addresses the minimal set of critical issues

    A rare complication of acute appendicitis – case presentation

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    Introduction. Considered by many authors a vestigial structure, the appendix is a small dimensions organ with mostly unknown functions. Acute appendicitis is the most common condition of the ileocecal appendix, having multifaceted clinical manifestations, often masquerading as various unrelated syndromes, but causing increased morbidity, especially when diagnosed late. Although the disease could manifest at any age, there is a progressive increase of its incidence from birth, with a maximum between 10 to 40 years. Case presentation. We report the case of an 84 years-old female patient, who presented with significant abdominal pain in the lower quadrants, mainly in the right iliac fossa and in whom the CT examination was suggestive of a utero-appendicular fistula, a very rare complication in daily practice and even more seldomly encountered in the elderly. Conclusions. Acute appendicitis remains a condition for which surgery is still the optimum treatment, especially in the case of an elderly patient having a radiologically suspected fistula with the uterus that could easily lead to septic gynecological complications and possibly progression to multiple organ failure

    Systemic lupus erythematosus – the discrepancy between renal impairment and clinical and immunological manifestations

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    Systemic lupus erythematosus (SLE) is the prototype of autoimmune diseases with multiorgan involvement, most commonly targeting the skin, joints and kidneys. The existence and type of renal involvement influence the prognosis and this information may be crucial when it comes to establishing the optimal therapy. We present the case of a patient with SLE with skin involvement (vasculitis), joint manifestations and immunological markers remitted under synthetic remissive treatment but with severe renal damage diagnosed at the renal biopsy as a glomerulosclerosis type focal segmental podocytopathy (FSGS) collapsing variant associated with a possible ultrastructural defect of the glomerular basement membrane in the context of the disease with a severe prognosis
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