1,664 research outputs found

    A Constructivist-Based Approach to Teaching Database Analysis and Design

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    The study of database systems is typically core in undergraduate and postgraduate courses related to computer science and information systems. However, there are parts of this curriculum that learners find difficult, in particular, the abstract and complex domain of database analysis and design, an area that is critical to the development of modem information systems that meet the demands of users in an efficient and effective way. In addition, there is some evidence that companies believe the database analysis and design skills of both new graduate recruits and some of their existing IT staff are insufficient to cope with the complexities encountered in developing such systems. This paper reflects on these difficulties and describes a teaching approach motivated by principles found in the constructivist epistemology to help overcome these difficulties and help provide the learner with the knowledge and higher-order skills necessary to understand and perform database analysis and design effectively as a professional practitioner. The paper presents some preliminary results of this work that seems to suggest that students can learn how to design effective modern information systems when the learning is embedded in problem-solving contexts that are relevant in the real-world

    O∣|R∣|P∣|E -- A Data Semantics Driven Concurrency Control

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    This paper presents a concurrency control mechanism that does not follow a 'one concurrency control mechanism fits all needs' strategy. With the presented mechanism a transaction runs under several concurrency control mechanisms and the appropriate one is chosen based on the accessed data. For this purpose, the data is divided into four classes based on its access type and usage (semantics). Class OO (the optimistic class) implements a first-committer-wins strategy, class RR (the reconciliation class) implements a first-n-committers-win strategy, class PP (the pessimistic class) implements a first-reader-wins strategy, and class EE (the escrow class) implements a first-n-readers-win strategy. Accordingly, the model is called \PeFS. The selected concurrency control mechanism may be automatically adapted at run-time according to the current load or a known usage profile. This run-time adaptation allows \Pe to balance the commit rate and the response time even under changing conditions. \Pe outperforms the Snapshot Isolation concurrency control in terms of response time by a factor of approximately 4.5 under heavy transactional load (4000 concurrent transactions). As consequence, the degree of concurrency is 3.2 times higher.Comment: 20 pages, 7 tables, 15 figure

    Simulating infiltration and the water balance in cropping systems with APSIM-SWIM

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    We test APSIM-SWIM's ability to simulate infiltration and interactions between the soil water balance and grain crop growth using soil hydraulic properties derived from independent, point measurements. APSIMSWIM is a continuous soil-crop model that simulates infiltration, surface crusting, and soil condition in more detail than most other soil-crop models. Runoff, soil water, and crop growth information measured at sites in southern Queensland was used to test the model. Parameter values were derived directly from soil hydraulic properties measured using rainfall simulators, disc permeameters and ponded rings, and pressure plate apparatus. In general, APSIM-SWIM simulated infiltration, runoff, soil water and the water balance, and yield as accurately and reliably as other soil crop models, indicating the model is suitable for evaluating effects of infiltration and soil-water relations on crop growth. Increased model detail did not hinder application, instead improving parameter transferability and utility, but improved methods of characterising crusting, soil hydraulic conductivity, and macroporosity under field conditions would improve ease of application, prediction accuracy, and reliability of the model. Model utility and accuracy would benefit from improved representation of temporal variation in soil condition, including effects of tillage and consolidation on soil condition and bypass flow in cracks

    Ischemic Colitis Secondary to Ergotamine Use: A Case Study

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    A 48-year-old woman with a history of chronic migraines, initially admitted for inpatient management of intractable migraine headaches, developed new onset abdominal pain, hypotension, and diarrhea on hospital day number ten. In our institution's headache unit, patients are treated by a multidisciplinary approach, including individualized drug therapy based on diagnosis and previous response to therapy. Given the patient's hypotension and clinical appearance, she was transferred to the intensive care unit and treated for septic shock and metabolic acidosis. A bedside colonscopy revealed diffuse ischemic colitis. Final pathology after colon resection showed widespread, transmural necrosis of the colonic wall. We review the pathophysiology of ergotamine use and its potential association with ischemic colitis

    Superconducting Gatemon Qubit based on a Proximitized Two-Dimensional Electron Gas

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    The coherent tunnelling of Cooper pairs across Josephson junctions (JJs) generates a nonlinear inductance that is used extensively in quantum information processors based on superconducting circuits, from setting qubit transition frequencies and interqubit coupling strengths, to the gain of parametric amplifiers for quantum-limited readout. The inductance is either set by tailoring the metal-oxide dimensions of single JJs, or magnetically tuned by parallelizing multiple JJs in superconducting quantum interference devices (SQUIDs) with local current-biased flux lines. JJs based on superconductor-semiconductor hybrids represent a tantalizing all-electric alternative. The gatemon is a recently developed transmon variant which employs locally gated nanowire (NW) superconductor-semiconductor JJs for qubit control. Here, we go beyond proof-of-concept and demonstrate that semiconducting channels etched from a wafer-scale two-dimensional electron gas (2DEG) are a suitable platform for building a scalable gatemon-based quantum computer. We show 2DEG gatemons meet the requirements by performing voltage-controlled single qubit rotations and two-qubit swap operations. We measure qubit coherence times up to ~2 us, limited by dielectric loss in the 2DEG host substrate

    What makes for prize-winning television?

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    We investigate the determinants of success in four international television awards festivals between 1994 and 2012. We find that countries with larger markets and greater expenditure on public broadcasting tend to win more awards, but that the degree of concentration in the market for television and rates of penetration of pay-per-view television are unrelated to success. These findings are consistent with general industrial organisation literature on quality and market size, and with media policy literature on public service broadcasting acting as a force for quality. However, we also find that ‘home countries’ enjoy a strong advantage in these festivals, which is not consistent with festival success acting as a pure proxy for television quality

    Development and evaluation of two 3D-simulated practice learning environments

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    This paper discusses the evaluation of two 3D simulated practice learning environments, Tiny Oaks and Play2Do, focused on supporting people working with children, families, and vulnerable people in special educational settings. Pre-test/post-test evaluation methodology was employed consisting of a questionnaire with 16 questions covering knowledge and understanding, professional practice, and transferable skills. Tiny Oaks had 530 participants pre-test and 423 post-test from six European countries, and results show a significant increase in learning across all questions. Play2Do had 318 participants pre-test and 301 participants post-test from the UK and Bulgaria, and again results show a significant increase in learning across all questions. The system usability scale (SUS) questionnaire was also used to measure the usability of the two environments, and usability was found to be excellent. Findings suggest that 3D simulated practice environments can provide a valuable learning experience and can provide practice learning scenarios that may be difficult to encounter in real-life

    A systematic review of technologies and standards used in the development of rule-based clinical decision support systems

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    A Clinical Decision Support System (CDSS) is a technology platform that uses medical knowledge with clinical data to provide customized advice for an individual patient's care. CDSSs use rules to encapsulate expert knowledge and rules engines to infer logic by evaluating rules according to a patient's specific information and related medical facts. However, CDSSs are by nature complex with a plethora of different technologies, standards and methods used to implement them and it can be difficult for practitioners to determine an appropriate solution for a specific scenario. This study's main goal is to provide a better understanding of different technical aspects of a CDSS, identify gaps in CDSS development and ultimately provide some guidelines to assist their translation into practice. We focus on issues related to knowledge representation including use of clinical ontologies, interoperability with EHRs, technology standards, CDSS architecture and mobile/cloud access. This study performs a systematic literature review of rule-based CDSSs that discuss the underlying technologies used and have evaluated clinical outcomes. From a search that yielded an initial set of 1731 papers, only 15 included an evaluation of clinical outcomes. This study has found that a large majority of papers did not include any form of evaluation and, for many that did include an evaluation, the methodology was not sufficiently rigorous to provide statistically significant results. From the 15 papers shortlisted, there were no RCT or quasi-experimental studies, only 6 used ontologies to represent domain knowledge, only 2 integrated with an EHR system, only 5 supported mobile use and only 3 used recognised healthcare technology standards (and all these were HL7 standards). Based on these findings, the paper provides some recommendations for future CDSS development that should be of interest to software developers of CDSSs and also health practitioners involved in commissioning or development
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