Improving Domain-Specific Language Reuse with Software Product Line Techniques

Developing a domain-specific language (DSL) or a composition of DSLs to model a system concern, such as deploying and configuring software components to meet real-time scheduling constraints, is time consuming. Ideally, developers should be able to reuse DSLs and DSL compositions across projects to amortize development effort. Reusing DSLs is hard, however, because they're often designed to precisely describe a single domain or concern. A new approach uses techniques from software product lines (SPLs) to improve the reusability of a DSL, DSL composition, or supporting tool by providing traceability of language concepts to DSL design. A case study of four DSLs demonstrates the need for—and benefits of—applying SPL reuse techniques to DSLs.     

Multimedia vectorization of floating‐point MIN/MAX reductions

Finding the minimum or maximum value in an array forms an important step in a variety of applications. This paper discusses vectorization schemes that take advantage of the streaming‐SIMD‐extensions in commonly used floating‐point MIN and MAX reductions. Performance advantages are demonstrated with experimental results. Copyright © 2006 John Wiley & Sons, Ltd.     

Health and climate benefits of cookstove replacement options

The health and climate impacts of available household cooking options in developing countries vary sharply. Here, we analyze and compare these impacts (health; climate) and the potential co-benefits from the use of fuel and stove combinations. Our results indicate that health and climate impacts span 2 orders of magnitude among the technologies considered. Indoor air pollution is heavily impacted by combustion performance and ventilation; climate impacts are influenced by combustion performance and fuel properties including biomass renewability. Emission components not included in current carbon trading schemes, such as black carbon particles and carbon monoxide, can contribute a large proportion of the total climate impact. Multiple ‘improved’ stove options analyzed in this paper yield roughly equivalent climate benefits but have different impacts on indoor air pollution. Improvements to biomass stoves can improve indoor air quality, which nonetheless remains significantly higher than for stoves that use liquid or gaseous hydrocarbons. LPG- and kerosene-fueled stoves have unrivaled air quality benefits and their climate impacts are also lower than all but the cleanest stoves using renewable biomass.     

可精确测距的低成本超声子系统

超声测距原理 超声传感器电路比较简单,在系统中负责发送超声脉冲流,然后采集回波信号.器件发出的脉冲信号在空气中传输,直到碰到一个目标物体并在此处产生反射回波.超声传感器通过检测这些回波,并计算出发射脉冲与接收脉冲之间的时间差,从而确定脉冲波形的传输距离.     

Oligomerization of alkynes by hafnocene dichloride/ethylaluminum dichloride

Summary The Cp₂HfCl₂/C₂H₅AlCl₂ system (Cp = ⁵-cyclopentadienyl) was found to be an active homogeneous catalyst for the Oligomerization of both terminal and internal alkynes. Apparently, the mechanism of Oligomerization occurs by successive insertion of the alkyne into the hafnium-carbon bond of a cationic intermediate, as evidenced by the interception of the highly substituted, sterically bulky, 1-trimethylsily1-1-propyne.     

Moving boundary approach to forecast tight oil production

A novel semianalytical production predictive tool for tight reservoirs based on the application of material balance on a transient linear flow system is developed in this paper. This method considers two important regions during transient production of oil reservoirs: the saturated region where gas evolves and flows with oil, and the undersaturated region where only oil flows. A zonal moving boundary approach is used to evolve the two regions as the reservoir pressure gradually decreases. A semianalytical method is used to calculate pressures in the various regions and volumetric expansions. For both black oil and volatile oil scenarios, calculations from this analytical framework are able to match reservoir pressures, oil and gas rates, and cumulative gas–oil ratios determined using a reservoir simulator. The model was also applied to wells in tight reservoirs around the United States such as the Bakken (ND) and the Eagle Ford (TX) with reasonable success.