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21.
Punter Teade Kusters Rob Trienekens Jos Bemelmans Theo Brombacher Aarnout 《Software Quality Journal》2004,12(2):137-158
The importance of software product evaluations will grow with the awareness of the need for better software quality. The process to conduct such evaluations is crucial to get evaluation results that can be applied and meet customers' expectations. This paper reviews a well-known evaluation process: the ISO 14598 standard. The review focuses on the difficulties in selecting and evaluating the appropriate evaluation techniques. The review shows that the standard has problems in applying evaluation processes in practice due to insufficient attention to goal definition and to relationships between activities being implicit. Also, the standard ignores the trade-off between goals and resources and pays insufficient attention to feedback. To address these deficiencies, the W-process is proposed. It extends the standard through an improved process structure and additional guidelines. 相似文献
22.
Hildrun Kretschmer Ramesh Kundra Donald deB. Beaver Theo Kretschmer 《Scientometrics》2012,93(1):135-150
The causes of gender bias favoring men in scientific and scholarly systems are complex and related to overall gender relationships in most of the countries of the world. An as yet unanswered question is whether in research publication gender bias is equally distributed over scientific disciplines and fields or if that bias reflects a closer relation to the subject matter. We expected less gender bias with respect to subject matter, and so analysed 14 journals of gender studies using several methods and indicators. The results confirm our expectation: the very high position of women in co-operation is striking; female scientists are relatively overrepresented as first authors in articles. Collaboration behaviour in gender studies differs from that of authors in PNAS. The pattern of gender studies reflects associations between authors of different productivity, or ??masters?? and ??apprentices?? but the PNAS pattern reflects associations between authors of roughly the same productivity, or ??peers??. It would be interesting to extend the analysis of these three-dimensional collaboration patterns further, to see whether a similar characterization holds, what it might imply about the patterns of authorship in different areas, what those patterns might imply about the role of collaboration, and whether there are differences between females and males in collaboration patterns. 相似文献
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This article analyzes the challenges of supporting continual changes of context information in Internet-of-Things applications. These applications require a constant flow of continuously changing information from sensor based sources in order to ensure a high quality-of-experience. However, an uncontrolled flow between sources and sinks on a global scale wastes resources, such as computational power, communication bandwidth, and battery time. In response to these challenges we present a general approach which focuses on four layers where we provide a proposed solution to each layer. We have realized the general model into a proof-of-concept implementation running on devices with limited resources, where we can moderate the information exchange based on relevance and sought after quality-of-experience by the applications. In conclusion, we evaluate our solution and present a summary of our experiences regarding the impact of continuously changing information on the Internet-of-Things. 相似文献
25.
Sheldon M. Wiederhorn Theo Fett Gabriele Rizzi Michael J. Hoffmann Jean-Pierre Guin 《Metallurgical and Materials Transactions A》2013,44(3):1164-1174
When a crack forms in silica glass, the surrounding environment flows into the crack opening, and water from the environment reacts with the glass to promote crack growth. A chemical reaction between water and the strained crack-tip bonds is commonly regarded as the cause of subcritical crack growth in glass. In silica glass, water can also have a secondary effect on crack growth. By penetrating into the glass, water generates a zone of swelling and, hence, creates a compression zone around the crack tip and on the newly formed fracture surfaces. This zone of compression acts as a fracture mechanics shield to the stresses at the crack tip, modifying both the strength and subcritical crack growth resistance of the glass. Water penetration is especially apparent in silica glass because of its low density and the fact that it contains no modifier ions. Using diffusion data from the literature, we show that the diffusion of water into silica glass can explain several significant experimental observations that have been reported on silica glass, including (1) the strengthening of silica glass by soaking the glass in water at elevated temperatures, (2) the observation of permanent crack face displacements near the crack tip of a silica specimen that had been soaked in water under load, and (3) the observation of high concentrations of water close to the fracture surfaces that had been formed in water. These effects are consistent with a model suggesting that crack growth in silica glass is modified by a physical swelling of the glass around the crack tip. An implication of water-induced swelling during fracture is that silica glass is more resistant to crack growth than it would be if swelling did not occur. 相似文献
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Climate change benefits and energy supply benefits as determinants of acceptance of nuclear power stations: Investigating an explanatory model 总被引:1,自引:0,他引:1
Several countries are currently discussing whether they will rebuild their nuclear power stations in order to continue this type of energy production in the future. The public, with its own opinion about nuclear power stations, has an influential voice in this discussion. As a result, policy makers and nuclear scientists are interested in the public's perception of nuclear power and in what determines this perception. We therefore examined an explanatory model of the public's acceptance of nuclear power based on a telephone survey among a representative sample in Switzerland. The model included such factors as risk perception, benefit perception, affective feelings, and social trust. Moreover, we distinguished between two types of benefit perception: benefit for the climate and a secure energy supply. The model fitted very well to our data and explained acceptance very well. Acceptance was mainly influenced by perceived benefits for a secure energy supply and, to a lesser extent, both by perceived benefits for the climate and by risk perception. Affective feelings about nuclear power appeared to be a central factor in the model. Implications for communication about nuclear power stations and for further research are discussed. 相似文献
28.
Akylbek Sydykov Himal Luitel Argen Mamazhakypov Malgorzata Wygrecka Kabita Pradhan Oleg Pak Aleksandar Petrovic Baktybek Kojonazarov Norbert Weissmann Werner Seeger Friedrich Grimminger Hossein Ardeschir Ghofrani Djuro Kosanovic Ralph Theo Schermuly 《International journal of molecular sciences》2020,21(23)
Although the response of the right ventricle (RV) to the increased afterload is an important determinant of the patient outcome, very little is known about the underlying mechanisms. Mast cells have been implicated in the pathogenesis of left ventricular maladaptive remodeling and failure. However, the role of mast cells in RV remodeling remains unexplored. We subjected mast cell-deficient WBB6F1-KitW/W-v (KitW/KitW-v) mice and their mast cell-sufficient littermate controls (MC+/+) to pulmonary artery banding (PAB). PAB led to RV dilatation, extensive myocardial fibrosis, and RV dysfunction in MC+/+ mice. In PAB KitW/KitW-v mice, RV remodeling was characterized by minimal RV chamber dilatation and preserved RV function. We further administered to C57Bl/6J mice either placebo or cromolyn treatment starting from day 1 or 7 days after PAB surgery to test whether mast cells stabilizing drugs can prevent or reverse maladaptive RV remodeling. Both preventive and therapeutic cromolyn applications significantly attenuated RV dilatation and improved RV function. Our study establishes a previously undescribed role of mast cells in pressure overload-induced adverse RV remodeling. Mast cells may thus represent an interesting target for the development of a new therapeutic approach directed specifically at the heart. 相似文献
29.
Verwaal R Paalman JW Hogenkamp A Verkleij AJ Verrips CT Boonstra J 《Yeast (Chichester, England)》2002,19(12):1029-1038
In the yeast Saccharomyces cerevisiae, hexose transporter (Hxt) proteins transport glucose across the plasma membrane. The Hxt proteins are encoded by a multigene family with 20 members, of which Hxt1-4p and Hxt6-7p are the major hexose transporters. The remaining Hxt proteins have other or unknown functions. In this study, expression of HXT5 under different experimental set-ups is determined. In glucose-grown batch cultures, HXT5 is expressed prior to glucose depletion. Independent of the carbon source used in batch cultures, HXT5 is expressed after 24 h of growth and during growth on ethanol or glycerol, which indicates that growth on glucose is not necessary for expression of HXT5. Increasing the temperature or osmolarity of the growth medium also induces expression of HXT5. In fed-batch cultures, expression of HXT5 is only observed at low glucose consumption rates, independent of the extracellular glucose concentration. The only common parameter in these experiments is that an increase of HXT5 expression is accompanied by a decrease of the growth rate of cells. To determine whether HXT5 expression is determined by the growth rate, cells were grown in a nitrogen-limited continuous culture, which enables modulation of only the growth rate of cells. Indeed, HXT5 is expressed only at low dilution rates. Therefore, our results indicate that expression of HXT5 is regulated by growth rates of cells, rather than by extracellular glucose concentrations, as is the case for the major HXTs. A possible function for Hxt5p and factors responsible for increased expression of HXT5 upon low growth rates is discussed. 相似文献
30.
Ozonation reduces sludge production and improves denitrification 总被引:2,自引:0,他引:2
The effectiveness of partial ozonation of return activated sludge for enhancing denitrification and waste sludge minimization were examined. A pair of nitrifying sequencing batch reactors was operated in either aerobic or alternating anoxic/aerobic conditions, with one control and one ozonated reactor in each set. The amount of solids produced decreased with the ozone dose. Biomass in the anoxic/aerobic reactor was easier to destroy (up to 25% of the initial excess sludge) than in the aerobic (10%) one, generating approximately twice as much soluble COD by cell lysis. Denitrification rate improved up to 60% due to additional carbon released by ozonation. Nitrification rates deteriorated much more in the aerobic than in the alternating reactor, possibly as a result of direct destruction of nitrifying autotrophs as well as competition created by growth of heterotrophs receiving the additional COD. Overall, ozonation provided the expected benefits in denitrification and had less impact on nitrification in the alternating reactors. 相似文献