EDA工具适应当今的FPGA设计

几年以前,高容量的现场可编程器件(FPGA)指 的是包含有5万个门电路,应用于逻辑结合比较紧密的 电路。但今天的FPGA已包含数百万个门电路,成为某 些增长最快的高科技市场的电子系统核心。摩尔定律在FPGA上呈现,包括门数与速率。高容量、高性能的FPGA已处在硅技术的前沿,甚至在某些场合替代了ASIC。     

Exploring the Gender Gap in Engineering: A Re‐Specification and Test of the Hypothesis of Cumulative Advantages and Disadvantages

Researchers using the hypothesis of cumulative advantages and disadvantages argue that the accumulation of small advantages for men and small disadvantages for women contributes to the gender gap in engineering. This paper uses data from a 1998 survey of engineering undergraduates to test a re‐specification of this hypothesis that treats the gender distribution of advantages and disadvantages as an empirical question. We considered four sets of factors that have been shown to promote choice of an engineering major, persistence in engineering, and progress in engineering: family background, high school participation in mathematics and science, university participation in engineering, and integration into engineering. We found gender differences for each set of factors. We also found that men and women accumulate different advantages and disadvantages as they move through the education pipeline. By demonstrating that the accumulation of advantages and disadvantages is gendered, these results highlight the importance of examining the impact of micro‐inequities on the persistence and progress of men and women in engineering.     

Underrated transformations in the open space—The case of an urbanized and multifunctional area

The open space in Flanders is subjected to different transformation processes. These processes are related to dynamic interactions within an urbanizing society and to competition for space by an increasing number of functions. Despite the acknowledgement of dynamic land use demands, the current categorizations of land use and land cover are not always able to catch transformations related to e.g. newcomers in land use, ecosystem services and multifunctionality in mixed urban–rural areas. Remote sensing tools and census data are insufficient when studying a complex and intensively used space. This research therefore aims to identify underrated transformations in the study area Flanders (the northern part of Belgium) using two main sources: (i) open expert interviews and (ii) three case studies. The interviews serve to formulate a renewed framework that can be used to describe transformations in the open space. The transformation processes that emerge from the interviews and case studies are compared to those defined and recognized in the current spatial planning policy and in existing monitoring data, in order to identify bottlenecks and options for future spatial planning policy. The major conclusions of this paper are (i) a critical view on the analysis and categorization of functions and open space as it is currently practiced in land use monitoring and land use planning programs, (ii) additional data needs to encompass transformation processes in the open space and (iii) the need for a more integral vision for open space.     

Trace metals and organochlorines in the bamboo shark Chiloscyllium plagiosum from the southern waters of Hong Kong, China

The bamboo shark Chiloscyllium plagiosum is an abundant benthic species along the shallow continental shelf of Southeast Asia. It is commonly taken by fishermen in China, India, Taiwan and Thailand for human consumption. This study measured trace metal and organochlorine concentrations in C. plagiosum collected from the southern waters of Hong Kong, China. Metals (Ag, Cd, Cr, Cu, Mn, Ni, Pb and Zn) were measured in three different tissues: dorsal muscle, spleen and liver. Polychlorinated biphenyls (PCBs) and chlorinated pesticides in the dorsal muscle were identified and quantified using gas chromatography. Metal concentrations varied among the three different tissues, with liver having higher levels of Ag and Cd, and spleen possessing higher levels of Cu and Mn. Both Ni and Pb in all tissues were below the detection limit. Tissue concentrations of Cr, Cu, Mn and Zn generally decreased with increasing body weight whilst no significant concentration-size relationship was found for other metals. In muscle tissues, total PCBs ranged from 1.056-4.771 ng/g (wet wt.) with a median of 1.801 ng/g, while total DDTs ranged from 0.602-23.55 ng/g with a median of 1.109 ng/g, in which p,p'-DDE was the predominant metabolite. Levels of total hexachlorohexanes and cyclodienes were low. The pesticide p,p'-DDT was the only compound found to be positively correlated with body weight, indicating temporal bioaccumulation of this compound. Zn concentrations in the muscle of C. plagiosum were comparatively higher than recorded in other shark species, however, concentrations of other metals and organochlorines were relatively low. C. plagiosum feeds primarily on polychaetes, shrimps and small fishes, and thus is unlikely to contain levels of contaminants of human health concern.     

Thermodynamics of hydrogen production from urea by steam reforming with and without in situ carbon dioxide sorption

The thermodynamic effects of molar steam to carbon ratio (S:C), of pressure, and of having CaO present on the H₂ yield and enthalpy balance of urea steam reforming were investigated. At a S:C of 3 the presence of CaO increased the H₂ yield from 2.6 mol H₂/mol urea feed at 940 K to 2.9 at 890 K, and decreased the enthalpy of bringing the system to equilibrium. A minimum enthalpy of 180.4 kJ was required to produce 1 mol of H₂ at 880 K. This decreased to 94.0 kJ at 660 K with CaO-based CO₂ sorption and, when including a regeneration step of the CaCO₃ at 1170 K, to 173 kJ at 720 K. The presence of CaO allowed widening the range of viable operation at lower temperature and significantly inhibited carbon formation. The feasibility of producing H₂ from renewable urea in a low carbon future is discussed.     

Grain subdivision and recrystallization in oligocrystalline tantalum during cold swaging and subsequent annealing

A coarse-grained ingot of high-purity tantalum was deformed by swaging at room temperature to a strain of 1.28. During annealing at 900°C for 30 min two neighboring grains were observed to behave quite differently. Electron backscattering diffraction (EBSD) results show noticeable differences in terms of the misorientations developed in both grains. The grain developing larger misorientations recrystallized much more readily than the other. The result is interpreted in terms of the differences in grain subdivision into strongly misoriented regions.     

Initial feasibility of a researcher configurable computerized self-monitoring system

This study sought to evaluate the feasibility of a researcher configurable self-monitoring program. An initial prototype of the program was developed as a Windows-based drag and drop flow chart interface for the researcher to construct the self-monitoring or diary protocol to be scheduled and displayed to the subject on a Pocket PC. The usability of the desktop researcher interface was evaluated in a small sample of medication trial researchers whose ratings of the prototype were generally positive and provided directions for improvement. The subject interface was then evaluated in an “analog” drug trial of 49 smokers using nicotine gum. These subjects were randomly assigned to either paper-based log or Pocket PC self-monitoring for 3 weeks. Pocket PC subjects were significantly more compliant than the log subjects on recording in the second (65% vs. 39%) and third (69% vs. 39%) weeks of the trial but did not differ from the log condition on total recording entries, likely due to the restrictions on retrospective recording in the Pocket PC program. This study provides support for the feasibility of a researcher configurable electronic diary system which should substantially reduce the programming barriers to electronic self-monitoring and increase the use of real-time monitoring in clinical and research venues.     

Orientation invariant pattern recognition by pigeons (Columba livia) and humans (Homo sapiens).

The orientation invariance of visual pattern recognition in pigeons and humans was studied using a conditioned matching-to-sample procedure. A rotation effect, a lengthening of choice latencies with increasing angular disparities between sample and comparison stimuli, was replicated with humans. The choice speed and accuracy of pigeons was not affected by orientation disparities. Novel mirror-image stimuli, rotation of sample shapes, a delayed display of comparison shapes, and a mixed use of original and reflected sample shapes did not lead to a rotation effect in pigeons. With arbitrarily different odd comparison shapes, neither humans nor pigeons showed a rotation effect. Final experiments supported the possibility that the complete absence of a rotation effect in pigeons is because they are relatively better than humans at discriminating mirror-image shapes compared with arbitrary shapes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motor recovery after stroke depends on intact sustained attention: A 2-year follow-up study.

The functional recovery of 47 right-brain-damaged stroke patients was studied over a 2-year period. The researchers hypothesized that sustained attention capacity should predict the degree of motor and functional recovery over this period because of a proposed privileged role of sustained attention in learning-based recovery of function. As predicted, significant correlations were found between sustained attention capacity at 2 months and functional status (including the Barthel Index) at 2 years. This relationship was shown to exist independently of 2-month functional status. Furthermore, compared with a left-brain-damaged group of cerebrovascular accident (CVA) patients, the right-brain CVA group did not recover functional ability as well over the 2-year period. This increasing difference in functional status over a 2-year period was mirrored by an emerging difference in sustained attention capacity, in favor of the left-brain CVA group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dynamics of intention retrieval and coordination of action in event-based prospective memory.

Event-based prospective memory requires responding to cues in the environment that are associated with a previously established intention. Some researchers believe that intentions reside in memory with an above baseline level of activation, a phenomenon called the intention superiority effect. The authors of this study predicted that intention superiority would be masked by additional cognitive processes associated with successful event-based prospective memory. These additional processes include noticing the cue, retrieving the intention, and coordinating intention execution with the ongoing activity, In 3 experiments, intention superiority was demonstrated by faster latencies to the ongoing activity on failed prospective trials and the existence of the additional processes was demonstrated by slower latencies on successful trials. This study demonstrates the importance of investigating the microstructure of the cognitive components involved with processing and responding to an event-based prospective memory cue. (PsycINFO Database Record (c) 2010 APA, all rights reserved)