采用CPAChecker的动态程序验证

针对模型检测中状态空间爆炸问题,在CPAChecker的抽象谓词检测方法的基础上,提出了一种基于动态执行的检测方法. 首先,根据程序的控制流程图,对程序进行静态检测。 在静态检测的过程中,根据分支语句的确定性,利用动态执行的方法来加快检测的过程。 其中,抽象检测可以有效地限制系统模型的规模,动态执行不仅可以有效地减少静态检测导致的误判,而且有助于引导构建精确的系统模型,降低虚假反例的数量和不必要的反例分析和精化。 实验数据显示,这种算法明显提高了传统的反例引导谓词抽象精化算法的检测效率和准确率。     

一种具有QoS保证的无线分组调度算法

为提高系统吞吐量对指数规则（EXP-rule）调度算法进行了改进。改进的指数规则（WEXP-rule）算法根据各移动用户收发信道质量和业务传输的QoS要求动态调整各用户的业务传输优先级,确定下行共享信道的调度方案。并给出该算法的简化形式SWEXP-rule。仿真结果表明,与传统调度算法相比,SWEXP-rule算法在数据包传输时延受限的条件下具有无线信道利用率高、实现复杂度低等特点。     

一种用于超高频RFID阅读器的正交下变频混频器的分析与设计

分析了共用跨导级的正交下变频混频器的性能,包括电压转换增益、线性度、噪声系数和镜象抑制比,分析表明其在电流开关模式下比传统的Gilbert混频器对具有更好的性能.设计并优化了一个基于共用跨导级结构的用于超高频RFID阅读器的正交下变频混频器.在915MHz频段上,该混频器测得12.5dB的转换增益,10dBm的IIP3 ,58dBm的IIP2和17.6dB的SSB噪声系数.芯片采用0.18μm 1P6M RF CMOS工艺实现,在1.8V的电源电压下仅消耗3mA电流.     

啤酒企业实施《食品安全法》之我见

本文针对2009年6月1日实施的《食品安全法》,结合长期以来啤酒企业质量管理经验,从完善食品安全管理体系和食品安全的监管控制角度,提出了在啤酒企业如何实施《食品安全法》。     

一种支持解密外包的KP-ABE方案

针对现有密钥策略基于属性加密KP-ABE（Key-Policy Attribute-Based Encryption）方案在解密时存在用户端计算开销大、解密时间长等问题,一些方案提出将解密外包给云服务器,但这些方案并未给出外包解密的并行化方法,存在解密效率低的问题.本文提出一种支持解密外包的KP-ABE方案.在该方案中,把大部分解密计算外包给Spark平台;并根据KP-ABE的解密特点设计并行化解密算法,完成对叶子节点和根节点的并行化解密.性能分析表明,用户端仅需进行一次指数运算即可解密出共享数据,同时并行化设计能有效提高云端解密速率.     

Tuning parallel symbolic execution engine for better performance

Symbolic execution is widely used in many code analysis, testing, and verification tools. As symbolic execution exhaustively explores all feasible paths, it is quite time consuming. To handle the problem, researchers have paralleled existing symbolic execution tools (e.g., KLEE). In particular, Cloud9 is a widely used paralleled symbolic execution tool, and researchers have used the tool to analyze real code. However, researchers criticize that tools such as Cloud9 still cannot analyze large scale code. In this paper, we conduct a field study on Cloud9, in which we use KLEE and Cloud9 to analyze benchmarks in C. Our results confirm the criticism. Based on the results, we identify three bottlenecks that hinder the performance of Cloud9: the communication time gap, the job transfer policy, and the cache management of the solved constraints. To handle these problems, we tune the communication time gap with better parameters, modify the job transfer policy, and implement an approach for cache management of solved constraints. We conduct two evaluations on our benchmarks and a real application to understand our improvements. Our results show that our tuned Cloud9 reduces the execution time significantly, both on our benchmarks and the real application. Furthermore, our evaluation results show that our tuning techniques improve the effectiveness on all the devices, and the improvement can be achieved upto five times, depending upon a tuning value of our approach and the behaviour of program under test.     

视觉引导下的运动执行与运动想象EEG时频特征对比分析

近年来基于运动想象(Motor imagery,MI)的脑-机接口(Brain-computer interface,BCI)技术迅速发展,广泛运用于各个领域.为了比较运动执行(Motor execution,ME)与MI脑电活动的差异,本文提出一种基于脑电信号(Electroencephalogram,EEG)时频域...     

制浆造纸行业MES系统评价模型研究

制造执行系统MES是位于企业上层企业资源计划ERP和底层设备自动控制系统PCS之间,面向车间层的生产管理技术与实时信息系统。本文介绍了MES的概念、功能模型,阐述了MES在制造业中的重要地位,结合昆山钞票纸厂的生产实践,建立了MES系统的评价模型。该模型对于相关行业的管理信息化建设也具有一定的参考价值。     

Condensation: Regionalism and the Room in John Yeon's Watzek House

Mary Anne Beecher's discussion of Aubrey Watzek's house extends traditional notions of regionalism to the domain of the interior. She outlines numerous ways that the local landscape and history figure as condensed renditions within rooms, surfaces and details. It is here that we find evidence of interior atmosphere developed as identity within a specific cultural and geographical context. Copyright © 2008 John Wiley & Sons, Ltd.     

A Novel Mechanism for TRF of Plant-wide Material Flows in Process Industry MES

This paper is standing on the recent viewpoint originated from relevant industrial practices that well or-ganized tracing, representing and feedback （TRF） mechanism of material-flow information is crucial for system utility and usability of manufacturing execution systems （MES）, essentially, for activities on the side of multi-level decision making and optimization mainly in the planning and scheduling. In this paper, we investigate a key issue emphasized on a route of multi-level information evolution on the side of large-scale feedback, where material-flow states could evolve from the measuring data （local states） to networked event-type information cells （global states） and consequently to the key performance indicators （KPI） type information （gross states）. Importantly, with adapta-bilities to frequent structural dynamics residing in running material flows, this evolving route should be modeled as a suit of sophisticated mechanism for large-scale dynamic states tracking and representing so as to upgrade accu-racy and usability of the feedback information in MES. To clarify inherent complexities of this evolving route, the investigated issue is demonstrated from extended process systems engineering （PSE） point of view, and the TRF principles of the multi-level feedback information （states） are highlighted under the multi-scale methodology. As the main contribution, a novel mechanism called TRF modeling mechanism is introduced.