基于四阶段人工优化的软件流水技术

代码体积是优化存储资源有限的嵌入式系统的重要因素之一。针对该特点,使用oprofile性能分析工具,以EEMBC基准程序集作为工作负载,提出四阶段人工优化软件流水方法(FPMO)。电信类的自相关程序实验结果表明,FPMO以2.04%的代码增量为代价换来40.678%的性能提升,而单纯的编译器自动优化则以33.35%的体积膨胀换来38.33%的性能提升。     

基于调和映射的三维医学图像增强系统

医学成像仪器产生12位的体数据,然而普通显示器只支持8位的灰度图。如果使用普通显示器来显示医学图像,显卡会自动将这些12位数据转化成8位数据,这就造成了数据动态范围被压缩。解决这一问题,在2D领域通常使用昂贵的医学专用灰阶显示器。在3D领域却限制了医生使用三维可视化软件。尝试将一些在2D图像处理中使用的图像增强技术如加权平均模板,不同程度曝光等来实现色调映射算法等应用到三维体数据的显示当中,通过种种复杂的数据变换,使得在普通显示器上显示的8位灰度图呈现出更高的动态范围,得到更为生动、更加丰富的显示效果。这种技术也可以实现任意位数的转化,使得12位显示器的显示效果也可以得到增强。     

THT-MSMA：基于双哈希表的高效多模式匹配算法

摘　要 多字符串模式匹配是在给定的文本中并行查找多个模式串的一种方法。本文中提出THT-MSMA多模式匹配算法,该算法采用双哈希表来减少尝试比较的次数。分析表明,该算法适合于最短模式串长度很长的环境,时间复杂度要低于经典的算法,尝试比较次数少于传统的多模式匹配算法。最后,实验结果表明,THT-MSMA算法具有良好的时空性能。     

基于时空动态性的MANETs入侵防御模型

移动自组网(Mobile Ad Hoc Networks,MANETs)的固有特性(如有限资源、动态拓扑等)使其比有线网络更易遭受各种安全威胁。现有的MANETs安全技术不能有效适应这些特性,尤其是不能在网络性能和网络安全之间保持平衡。在MANETs时空动态性及其识别的基础上,构建了安全威胁和入侵防御收益与代价的量化评估指标体系,提出了一种系统化的MANETs入侵防御系统模型(IDMSLP),并实现基于网络安全和性能平衡的防御策略生成与防御性能优化方法。通过比较分析,IDMSLP可有效地克服已有MANETs安全技术存在的缺陷,可适于MANETs应用。     

服务器监控技术综述及展望

随着服务器在各个领域的广泛应用以及服务器规模的不断扩大,服务器监控技术对保障服务器长期有效地工作起着关键性作用。首先对服务器监控的需求进行了阐述;其次对心跳机制、智能平台管理接口(Intelligent Platform Management Interface,IPMI)、简单网络管理协议(Simple Network Management Protocol,SNMP)及虚拟化技术等关键技术进行了归纳和总结,在此基础上描述了国内外主流的监控产品,如IBM Tivoli、HP OpenView等,并对其功能进行了对比和分析;最后对监控技术的发展前景进行了展望,针对现有服务器对高可用性的需求,提出了一种面向高可用服务器的监控框架。     

Tactical combat movements: inter-individual variation in performance due to the effects of load carriage

An examination into the effects of carried military equipment on the performance of two tactical combat movement simulations was conducted. Nineteen Airfield Defence Guards performed a break contact (five 30-m sprints) and a fire and movement simulation (16 6-m bounds) in five load conditions (10–30 kg). Heavier loads significantly increased movement duration on the break contact (0.8%/kg load) and fire and movement (1.1%/kg). Performance deterioration was observed from the beginning to the end of the series of movements (bounds or sprints) with deterioration becoming significantly greater in heavier load conditions. Inter-individual variation between slower and faster participants showed a range in load effects; 0.6, 0.8%/kg for fast and 1.0, 1.4%/kg for slow (break contact, fire and movement, respectively). Velocity profiles revealed that the initial acceleration and peak velocity were the primary determinants of performance. As the duration of these tactical combat movements reflects periods of heightened vulnerability, these findings highlight important implications for commanders.

Practitioner Summary: Increasing amounts of carried military equipment impairs the performance of tactical combat movements. Examination of inter-individual variation in velocity profiles identified that the initial acceleration and the peak velocity achieved during sprints and bounds are key determinants of overall performance.     

Integrated control design for driver assistance systems based on LPV methods

The paper proposes a control design method for a driver assistance system. In the operation of the system, a predefined trajectory required by the driver with a steering command is followed. During manoeuvres the control system generates differential brake moment and the auxiliary front-wheel steering angle and changes the camber angles of the wheels in order to improve the tracking of the road trajectory. The performance specifications are guaranteed by the local controllers, i.e. the brake, the steering, and the suspension systems, while the coordination of these components is provided by the supervisor. The advantage of this architecture is that local controllers are designed independently, which is ensured by the fact that the monitoring signals are taken into consideration in the formalisation of their performance specifications. The fault-tolerant control can be achieved by incorporating the detected fault signals in their performance specifications. The control system also uses a driver model, with which the reference signal can be generated. In the control design, the parameter-dependent linear parameter-varyingmethod, which meets the performance specifications, is used. The operation of the control system is illustrated through different normal and emergency vehicle manoeuvres with a high-accuracy simulation software.     

Predictive capability of cognitive ability and cognitive style for spaceflight emergency operation performance

This study explores the effects of cognitive ability (information seeking, inference, spatial recognition, attention span, and attention allocation) and cognitive style (active-reflective, sensing-intuitive, visual-verbal, and sequential-global) on task performance of simulated spaceflight emergency operations that require judgment and operation on a Chinese spaceflight instrument board and the possible interaction effect with training experience. The performance criteria included task completion time and number of human errors. It was found that inference ability, spatial recognition ability, and attention span had significant effects on task completion time, while attention allocation ability had significant effect on the number of error. The participants with a sequential cognitive style made significantly fewer errors than those with a global cognitive style. Training experience significantly decreased task completion time. The participants with sequential cognitive style learnt faster than those with global cognitive style in the spaceflight instrument operations. With increasing training experience, the predictive capability of cognitive ability on performance decreased, whereas the predictive capability of the sequential-global cognitive style on performance increased.