RET670主变过励磁保护逻辑缺陷分析及其改进

介绍了一起在现场试验中发现的RET670主变过励磁保护无法启动220 kV以及500 kV断路器失灵保护故障。针对此现象对RET670主变过励磁保护固有逻辑及其外部可编程逻辑进行了详细的分析和试验,发现只有在提高过励磁保护出口跳闸脉宽整定时间时才能正常启动失灵保护,否则过励磁保护均无法启动失灵保护,将导致在主变故障同时220 kV或500 kV断路器拒动时事故扩大,存在很大的安全隐患。针对RET670过励磁保护逻辑和失灵保护逻辑无法配合的缺陷,文中提出了解决方案,可以解决RET670过励磁保护无法启动失灵保护问题。     

Official checks by an accredited laboratory on irradiated foods at an Italian market

Food irradiation can be used to increase the microbiological safety and to extend the shelf life of foods. European legislation states that any food or food ingredients must be labelled and every year each Member State, particularly Italy, has to carry out checks at marketing stage. This work reports on the results of analytical controls on 451 foodstuff samples over the period 2006–2011 performed by an Italian accredited laboratory using 4 different screening and confirmatory techniques: PSL, DNA Comet Assay, TL and ESR. A total of 18 samples were found non-compliant: 6 frog legs, 3 clams, 3 cuttlefish, 1 octopus and 1 shrimps from Vietnam; 3 squids, 1 white pepper and 1 chilli tofu from China. Non-compliances are due to both incorrect labelling and irradiation in not approved facilities in extra European/third countries. Check results also showed that among screening methods PSL is the most accurate, simple and practical standard to analyse most of samples (spices, herbs, supplements, mollusks, crustaceans and vegetables) with a low false positive classification (11%) whereas DNA Comet Assay revealed the highest percentage of false positive cases (26%). ESR is the suitable confirmatory method to detect dried fruits and foodstuffs (meat and fish product) containing bone, while TL is the best confirmatory method to detect herbs, spices and supplements, cephalopods, mollusks and crustaceans, besides fresh fruits and vegetables. In conclusion, by comparison with European data, this study suggests more checks on meat products (frog and poultry meats), fish products (cephalopods, mussels and crustacean) spices and supplements especially at import stage from countries where non approved irradiation facilities are operating (e.g. Vietnam and China).     

YC450（PSL2）游动滑车结构设计及强度分析

为符合探伤检验要求,设计开发了符合API8C PSL2级的超深井钻机配套作业的YC450游动滑车（简称游车）,对常规游车在结构上进行了改进,并通过UG NX7.5建模,应用有限元法进行分析,采用ASME Ⅷ规范进行强度校验.结果表明,此游车在强度上满足ASMEⅧ规范要求,结构上满足API8C PSL2级质量要求.     

基于几乎差集的多输入多输出雷达阵列稀疏优化方法

针对基于循环差集(Cyclic Difference Sets,CDS)的多输入多输出(Multiple-input Multiple-output,MIMO)雷达阵列稀疏方法由于现有CDS构造条件苛刻、集合数量有限而造成阵列配置数量较少的不足,提出了基于几乎差集(Almost Difference Sets,ADS)的MIMO雷达阵列稀疏优化方法.该方法可解析地确定发射、接收阵元位置,并先验预估虚拟阵列的方向图旁瓣上界.基于ADS的MIMO阵列在旁瓣性能上与基于CDS的阵列相近且优于随机阵列;ADS具有构造简单、阵列配置丰富的优势,有利于该方法的工程应用.仿真验证了所提方法的有效性.     

基于PSL断言的宽带电路交换芯片验证

利用基于PSL断言的验证方法验证了宽带电路交换芯片XYDXC160的设计。该芯片单片支持64路2.488Gb/s STM-16帧结构的SDH码流的输入/输出，实现1 024×1 024 STM-1流的无阻塞电路交换。断言技术的引入，降低了验证工作的复杂度，提高了验证的速度和效率，确保了验证工作的质量。     

The construction of information management system prototypes in Ada

The use of a data-flow diagram and data dictionary for the requirements specification of an information management system is described together with the benefits to be gained from using prototypes. Construction of such prototypes in Ada is discussed in detail with a simple example being given. The use of a flexible user interface, generic data-flows, exception handlers for error conditions and a top-down design method that makes use of separate compilation indicates that Ada is an appropriate language for the development of such systems. Consideration is also given to the use of Ada in the construction of actual as well as prototype information systems.     

基于PSL与XML的软件过程描述模型SPRM的设计和实现

本文在研究CMM的基础上提出了一种利用过程规范语言PSL对软件过程进行建模的思想，设计并给出了一个软件过程描述模型SPRM。该模型遵循CMM3级对软件过程定义的要求，采用XML Schema作为其统一描述语言，保证了软件过程的统一性和可扩展性，有利于实现软件过程的互操作与过程资源的共享，为实现统一的软件过程管理打下了基础。最后，本文利用SPRM模型实现了一个过程实例--简单评审过程，说明了如何利用SPRM定义企业的不同软件过程。     

Novel non-coherent integration method using binary phase-coded radar signal

The m series with 511 bits is taken as an example being applied in non-coherent integration algorithm. A method to choose the bi-phase code is presented,which is 15 kinds of codes are picked out of 511 kinds of m series to do non-coherent integration. It is indicated that the power increasing times of larger target sidelobe is less than the power increasing times of smaller target mainlobe because of the larger target’s pseudo-randomness. Smaller target is integrated from larger target sidelobe,which strengthens the detection capability of radar for smaller targets. According to the sidelobes distributing characteristic,a method is presented in this paper to remove the estimated sidelobes mean value for signal detection after non-coherent integration. Simulation results present that the SNR of small target can be improved approximately 6 . 5 dB by the proposed method.     

Synthesizing safe control-command systems out of reusable components

This paper presents a safe design method for control-command embedded systems. It investigates the problem of building control-command systems out of Commercial off the shelf (COTS) components. The design method proposed uses in synergy the formal verification (FV) and the Discrete Controller Synthesis (DCS) techniques. COTS are formally specified using temporal logic and/or executable observers. New functions are built by assembling COTS together. As the COTS assembly operation is seldom error-free, behavioral incompatibilities may persist between COTS. For these reasons, COTS assemblies need to be formally verified and if errors are found, an automatic correction is attempted using DCS. The control-command code generated by DCS needs hardware specific post-processing: a structural decomposition, followed by a controllability assessment, followed by a dedicated formal verification step, ensuring that no spurious behavior is added by DCS. The resulting system is ready for hardware (e.g. FPGA) implementation.     

覆盖率驱动的芯片功能验证设计与实现

随着芯片集成度的发展,芯片性能越来越高,而上市时间越来越短,芯片验证在芯片设计中非常关键并贯穿于整个设计过程,验证的效率和质量直接决定着芯片的成败。提出了基于覆盖率驱动的芯片功能验证方法,定义了基于功能点覆盖率驱动的验证流程,利用PSL语言描述断言检查很有效,通过模拟工具检查断言是否成功,从而判断设计是否满足系统的功能要求。在网络接口芯片实际应用中,有效地降低了验证工作的复杂度,同时提高了验证的速度和质量。利用功能覆盖率数据判断测试激励的正确性和完整性,同时用覆盖率数据定量评价验证进程,提高了整个设计的效率。