1,003 research outputs found

    Requirements Management Tools: A Quantitative Assessment

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    This report is primarily aimed at people with some background in Requirements Engineering or practitioners wishing to assess tools available for managing requirements. We provide a starting point for this assessment, by presenting a brief survey of existing Requirements Management tools. As a part of the survey, we characterize a set of requirements management tools by outlining their features, capabilities and goals. The characterization offers a foundation to select and possibly customize a requirements engineering tool for a software project. This report consists of three parts. In Part I we define the terms requirements and requirements engineering and briefly point out the main components of the requirements engineering process. In Part II, we survey the characteristics and capabilities of 6 popular requirements management tools, available in the market. We enumerate the salient features of each of theses tools. In Part III, we briefly describe a Synergistic Environment for Requirement Generation. This environment captures additional tools augmenting the requirements generation process. A description of these tools is provided. In the concluding section, we present a discussion defining the ideal set of characteristics that should be embodied in a requirements management tool. This report is adapted from a compendium of assignments that were prepared by the students in a Requirements Engineering class offered in the Department of Computer Science at Virginia Tech

    Problem Identification and Decomposition within the Requirements Generation Process

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    Only recently has the real importance of the requirements generation process and its requisite activities been recognized. That importance is underscored by the evolving partitions and refinements of the once all-encompassing (and somewhat miss-named) Requirements Analysis phase of the software development lifecycle. Continuing along that evolutionary line, we propose an additional refinement to the requirements generation model that focuses on problem identification and its decomposition into an associated set of user needs that drive the requirements generation process. Problem identification stresses the importance of recognizing and identifying the difference between a perceived state of the system and the desired one. We mention pre- and post-conditions that help identify and bound the problem and then present some methods and techniques that assist in refining that boundary and also in recognizing essential characteristics of the problem. We continue by presenting a process by which the identified problem and its characteristics are decomposed and translated into a set of user needs that provide the basis for the solution description, i.e, the set of requirements. Finally, to place problem identification and decomposition in perspective, we present them within the framework of the Requirements Generation Model

    Strong suppression of Coulomb corrections to the cross section of e+e- pair production in ultrarelativistic nuclear collisions

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    The Coulomb corrections to the cross section of e+ee^+e^- pair production in ultrarelativistic nuclear collisions are calculated in the next-to-leading approximation with respect to the parameter L=lnγAγBL=\ln \gamma_A\gamma_B (γA,B\gamma_{A,B} are the Lorentz factors of colliding nuclei). We found considerable reduction of the Coulomb corrections even for large γAγB\gamma_A\gamma_B due to the suppression of the production of e+ee^+e^- pair with the total energy of the order of a few electron masses in the rest frame of one of the nuclei. Our result explains why the deviation from the Born result were not observed in the experiment at SPS.Comment: 4 pages, RevTe

    Sensitivity of Cirrus and Mixed-phase Clouds to the Ice Nuclei Spectra in McRAS-AC: Single Column Model Simulations

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    The salient features of mixed-phase and ice clouds in a GCM cloud scheme are examined using the ice formation parameterizations of Liu and Penner (LP) and Barahona and Nenes (BN). The performance of LP and BN ice nucleation parameterizations were assessed in the GEOS-5 AGCM using the McRAS-AC cloud microphysics framework in single column mode. Four dimensional assimilated data from the intensive observation period of ARM TWP-ICE campaign was used to drive the fluxes and lateral forcing. Simulation experiments where established to test the impact of each parameterization in the resulting cloud fields. Three commonly used IN spectra were utilized in the BN parameterization to described the availability of IN for heterogeneous ice nucleation. The results show large similarities in the cirrus cloud regime between all the schemes tested, in which ice crystal concentrations were within a factor of 10 regardless of the parameterization used. In mixed-phase clouds there are some persistent differences in cloud particle number concentration and size, as well as in cloud fraction, ice water mixing ratio, and ice water path. Contact freezing in the simulated mixed-phase clouds contributed to transfer liquid to ice efficiently, so that on average, the clouds were fully glaciated at T approximately 260K, irrespective of the ice nucleation parameterization used. Comparison of simulated ice water path to available satellite derived observations were also performed, finding that all the schemes tested with the BN parameterization predicted 20 average values of IWP within plus or minus 15% of the observations

    Sodium channel myotonia may be associated with high-risk brief resolved unexplained events [version 1; peer review: awaiting peer review]

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    Brief resolved unexplained events (BRUEs) have numerous and varied causes posing a challenge to investigation and management. A subset of infants with the neuromuscular disorder sodium channel myotonia, due to mutations in the SCN4A gene, experience apnoeic events due to laryngospasm (myotonia) of the upper airway muscles that may present as a BRUE. We sought to ascertain the frequency, severity and outcome of infants carrying the G1306E SCN4A mutation commonly associated with this presentation. We report 12 new cases of individuals with the G1306E mutation from three unrelated families and perform a literature review of all published cases. Infants with the G1306E mutation almost universally experience laryngospasm and apnoeic events. The severity varies significantly, spans both low and high-risk BRUE categories or can be more severe than criteria for a BRUE would allow. At least a third of cases require intensive care unit (ICU) care. Seizure disorder is a common erroneous diagnosis. Apnoeas are effectively reduced or abolished by appropriate treatment with anti-myotonic agents. Probands with the G1306E mutation who are family planning need to be counselled for the likelihood of post-natal complications. There is readily available and extremely effective treatment for the episodic laryngospasm and apnoea caused by this mutation. Proactively seeking clinical evidence of myotonia or muscle hypertrophy with consideration of CK and EMG in high risk BRUEs or more complex apnoeic events may reduce avoidable and prolonged ICU admissions, patient morbidity and potentially mortality. Keyword

    Celiac Disease and Pediatric Type 1 Diabetes: Diagnostic and Treatment Dilemmas

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    Despite the advent of sensitive and specific serologic testing, routine screening for celiac disease (CD) in diabetic populations may not be universal practice, and many clinicians struggle to find the optimal approach to managing CD in pediatric Type 1 diabetes (T1D) patients. While some clinicians advocate screening for CD in all patients with T1D, others are unsure whether this is warranted. The diagnosis of patients who present with symptomatic CD, including malabsorption and obvious pathology upon biopsy, remains straightforward, with improvements noted on a gluten-free diet. Many patients identified by screening, however, tend to be asymptomatic. Evidence is inconclusive as to whether the benefits of screening and potentially treating asymptomatic individuals outweigh the harms of managing a population already burdened with a serious illness. This review focuses on current knowledge of CD in children and youth with T1D, highlighting important elements of the disease's pathophysiology, epidemiology, clinical presentation, and diagnostic challenges

    Туризм и внешняя торговля АР Крым: географические аспекты современного развития

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    Целью данной статьи является оценка современного состояния внешней торговли АР Крым и ее составляющей – туристской деятельности
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