352 research outputs found

    Compiling SHIM

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    Embedded systems demand concurrency for supporting simultaneous actions in their environment and parallel hardware. Although most concurrent programming formalisms are prone to races and non-determinism, some, such as our SHIM (software/hardware integration medium) language, avoid them by design. In particular, the behavior of SHIM programs is scheduling-independent, meaning the I/O behavior of a program is independent of scheduling policies, including the relative execution rates of concurrent processes. The SHIM project demonstrates how a scheduling-independent language simplifies the design, optimization, and verification of concurrent systems. Through examples and discussion, we describe the SHIM language and code generation techniques for both shared-memory and message-passing architectures, along with some verification algorithms

    Moisture Buffer Value of Building Materials

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    Building materials and furnishing used in contact with indoor air may have a positive effect to moderate the variations of indoor humidity seen in occupied buildings. Thus, very low humidity can be alleviated in winter, as well as can high indoor humidity in summer and during high occupancy loads. This way, materials can be used as a passive means of establishing indoor climatic conditions, which are comfortable for human occupancy, or for safe storing of artefacts which are sensible to humidity variation. But so far there has been a lack of a standardized figure to characterize the moisture buffering ability of materials. It has been the objective of a recent (ongoing until mid-2005) Nordic project to come up with such a definition, and to declare it in the form of a NORDTEST method. Apart from the definition of the term Moisture Buffer Value, there will also be a declaration of a test protocol which expresses how materials should be tested. Finally as a part of the project, some Round Robin Tests will be carried out on various typical building materials. The paper gives an account on the definition of the Moisture Buffer Value, it will outline the content of the test protocol, and it will give some examples of results from the Round Robin Tests

    Optimization of thermal insulation thickness pertaining to embodied and operational GHG emissions in cold climates – Future and present cases

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    Determining the optimal insulation thickness is useful for designing zero-emission buildings (ZEB) to minimize the environmental impacts. The energy required to heat buildings in cold climates is relatively high. Substantial reductions in the total energy usage of a building can be achieved by reducing the U-value of the external surfaces. Increasing the insulation thickness reduces the operational CO2 emissions, although simultaneously increases the embodied CO2 emissions from materials. To mitigate climate change, Norway and Denmark are trending towards stricter regulations to limit energy use in buildings. However, these countries have no current regulations in the building codes for limit embodied CO2 emissions from materials. This study analyzes the influence of the energy emission factor and future climate change (scenarios?) on the optimal insulation thickness. We used three independent models for case studies in Greenland and Norway. The differences between the case studies highlight the influence of model parameter choices, such as indoor climate, energy emission factor and material emissions, whereas the similarities may be used to analyze the problem from a broader perspective. The results show that optimal insulation thickness calculations are most valuable for case studies in which the energy emission factor is low. Considering energy emission factors above 25–30 g CO2eq/kWh, operational emissions dominated the calculation results in all case studies.publishedVersio

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Quality of life and symptom assessment in randomized clinical trials of bladder cancer: A systematic review

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    OBJECTIVES: Patient-reported outcomes (PRO) help patients, caretakers, clinicians, and policy makers make informed decisions regarding treatment effectiveness. Our objective was to assess the quality of PRO reporting and methodological strengths and weaknesses in randomized controlled trials (RCT) in bladder cancer.; METHODS: A systematic literature search of bladder cancer RCT published between January 2004 and March 2014 was performed. Relevant studies were evaluated using a predetermined extraction form that included trial demographics, clinical and PRO characteristics, and standards of PRO reporting based on recommendations of the International Society for Quality of Life Research.; RESULTS: In total, 9 RCTs enrolling 1,237 patients were evaluated. All studies were in patients with nonmetastatic disease. In 5 RCTs, a PRO was the primary end point. Most RCTs did not report the mode of administration of the PRO instrument or the methods of collecting data. No RCT addressed the statistical approaches for missing data.; CONCLUSIONS: We found that few RCTs in bladder cancer report PRO as an outcome. Efforts to expand PRO reporting to more RCTs and improve the quality of PRO reporting according to recognized standards are necessary for facilitating clinical decision making. Copyright 2015 Elsevier Inc. All rights reserved

    Unanswered ethical and scientific questions for trials of invasive interventions for coronary disease: The case of single vessel disease

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    Trials in the 1990s demonstrated that medical therapy is as effective as invasive therapies for treating single-vessel coronary disease. Yet more recent studies enrolling patients with this condition have focused on evaluating only invasive approaches, namely, stenting versus coronary artery bypass surgery. Several ethical and scientific questions remain unanswered regarding the conduct of these later trials. Were they justified? Why wasn't a medical therapy arm included? Were subjects informed about the availability of medical therapy as an equivalent option? Was optimized medical therapy given prior to randomization? The absence of clear answers to these questions raises the possibility of serious bias in favor of invasive interventions. Considering that medical therapy is underutilized in patients with coronary disease, efforts should focus more on increasing utilization of medical therapy and proper selection of noninvasive interventions
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