基于W5300的外系统等效器设计

针对飞行器测试实验阶段需要对飞行器各种信号进行模拟,以配合测试系统的工作,设计了一种基于以太网传输接口、以FPGA为控制核心的外系统等效器.该等效器采用W5300实现以太网与上位机进行通信,命令下发至主控板FPGA进行解析转发,来控制协调各个功能板产生需要的信号,包括27路直流信号、17路状态信号、15路脉冲信号以及3路正弦交流、平台力矩电流、数字串口、马达电源等信号.与其他设备联试结果显示,该等效器可靠性高且功能稳定,已成功应用于某航天测试系统.     

The Synchronous Approach to Designing Reactive Systems

Synchronous programming is available through several formally defined languages having very different characteristics: Esterel is imperative, while Lustre and Signal are declarative in style; Statecharts and Argos are graphical languages that allow one to program by constructing hierarchical automata. Our motivation for taking the synchronous design paradigm further, integrating imperative, declarative (or dataflow), and graphical programming styles, is that real systems typically have components that match each of these profiles. This paper motivates our interest in the mixed language programming of embedded software around a number of examples, and sketches the semantical foundation of the Synchronie toolset which ensures a coherent computational model. This toolset supports a design trajectory that incorporates rapid prototyping and systematic testing for early design validation, an object oriented development methodology for long term software management, and formal verification at the level of automatically generated object code.     

A multi-institutional, multinational study of programming concepts using card sort data

Abstract: This paper presents a case study of the use of a repeated single‐criterion card sort with an unusually large, diverse participant group. The study, whose goal was to elicit novice programmers' knowledge of programming concepts, involved over 20 researchers from four continents and 276 participants drawn from 20 different institutions. In this paper we present the design of the study and the unexpected result that there were few discernible systematic differences in the population. The study was one of the activities of the National Science Foundation funded Bootstrapping Research in Computer Science Education project (2003).     

电源备自投装置接线错误造成拒动事故分析

通过对新疆油田克拉玛依供电公司某变电所一起电源备投装置接线错误造成拒动进行详细分析,找出原因,吸取教训。     

Leaf and stem micromorphology of Byrsonima sericea DC. by light and scanning electron microscopy

Micromorphological studies were carried out using multiple microscopic techniques on the leaves and stem bark of Byrsonima sericea DC. (Malpighiaceae), a species popularly known as “murici” and used medicinally, in order to identify both qualitative and quantitative features of leaf and stem anatomy and histochemistry as differential parameters to support both the quality control of its ethnodrugs and the taxonomy of the genus. The study was conducted using traditional techniques of plant anatomy, histochemical tests, and the stomatal index (SI). Byrsonima sericea has hypostomatic leaves, anomocytic stomata, and its epidermal walls are anticlinal and straight on the adaxial and curved on the abaxial faces. T‐shaped trichomes were observed mainly on the abaxial surface. The leaf epidermis showed waxes syntopism on both surfaces, with the occurrence of different crystalloid forms on a single phylloplane. The mesophyll is dorsiventral, with 3‐4 collateral vascular bundles. Phenolic compounds, starch, and proteins were identified in the petiole and stem. The SI was 14.5 ± 0.53% (p < .05), but did not showed significant variations. A set of characters were found to be distinctive for the studied species, however, constituting parameters that could be used to separate B. sericea from other species of the genus.