Integrated guidance and control design based on a reference model

In this paper, an Integrated Guidance and Control (IGC) algorithm based on a reference model is proposed for a side-jet missile. First, a IGC structure is introduced, incorporating the response characteristics of the missile control loop into the guidance loop. To describe the response characteristics, then a reference model is built. Next, with the back stepping scheme and sliding mode control algorithm, the reference model is adopted to derive a novel guidance law, which contains response parameters of missile control system to formulate the IGC design. Finally, simulations and comparisons with the time-scale separation design and an existing IGC design, are conducted to verify the proposed IGC algorithm. It can be shown that the proposed algorithm performs better against highly maneuvering target in different missile-target initial position and heading scenarios.     

Design complexity control in truss optimization

Truss optimization based on the ground structure approach often leads to designs that are too complex for practical purposes. In this paper we present an approach for design complexity control in truss optimization. The approach is based on design complexity measures related to the number of bars (similar to Asadpoure et al. Struct Multidisc Optim 51(2):385–396 2015) and a novel complexity measure related to the number of nodes of the structure. Both complexity measures are continuously differentiable and thus can be used together with gradient based optimization algorithms. The numerical examples show that the proposed approach is able to reduce design complexity, leading to solutions that are more fit for engineering practice. Besides, the examples also indicate that in some cases it is possible to significantly reduce design complexity with little impact on structural performance. Since the complexity measures are non convex, a global gradient based optimization algorithm is employed. Finally, a detailed comparison to a classical approach is presented.     

基于深度图像的人体运动姿态跟踪和识别算法

由于人体运动的复杂性,现有基于低质量深度图像的三维立体姿态跟踪和识别 方法的准确性较低、鲁棒性较差。针对低质量深度图像的人体运动姿态和识别问题,本文设 计了一种基于三步搜索算法的人体运动姿态的跟踪和识别方法。该方法首先对获取的深度信 息进行分析,从而判定人体轮廓;然后通过基于深度图像的骨骼跟踪方法跟踪特定骨骼点, 并采用三步搜索算法进行运动估计,跟踪获取人体运动轨迹;最后利用获取的骨骼点坐标实 现人体运动姿态的识别。实验结果表明,该算法克服光照影响的鲁棒性较强,且能有效地提 高人体运动姿态跟踪与识别的准确性。     

基于iPhone手机的数字码实时识别与应用

根据苹果手机拍摄防伪标签数字实时识别的需要,针对防伪数字字号较小的因素和苹果手机因拍摄距离的原因造成的图像缩小、数字模糊、背景复杂等问题进行处理,提高识别精度。首先通过人工选取数字码区域,并进行背景数字分离,定位获取数字图像;其次采用灰度化和二值化得到黑白图像;然后通过投影对数字码图像进行分割,并对每个数字图像进行归一化、锐化和细化;基于统计学抽取数字码的特征,采用最近邻域判别函数进行数字码识别,取得很好的识别效果。     

音频、视频设备剩余电压检测技术研究

分析两种剩余电压测试方法—剩余电压测试仪法和数字存储示波器法的优、缺点,详细分析数字存储示波器法的输入阻抗、示波器供电电源、测试设备计量溯源等问题,并对最大剩余电压测量结果的不确定度进行分析评定,尽量减小各不确定度分量,以保证最高剩余电压的检测结果准确可靠。     

基于节点双向选择的水声传感网络自适应能量优化分配

针对水下传感器网络节点能量负载不均衡以及水下节点路径传输损耗过大等问题,为了平衡网络的节点能量分配,提高网络能量的利用效率,提出了一种基于节点双向选择的水声网络自适应能量优化分配算法。基于节点的剩余能量情况提出下一跳候选节点的双向选择方法,防止剩余能量过低的节点在传送数据时由于传输损耗过大而中止,充分考虑节点剩余能量和传输损耗之间的权衡,提出了最优转发节点的竞争公式,再通过比较候选节点的竞争值来选举最佳的下一跳节点。实验仿真表明,自适应能量优化分配算法能够有效地提高水下传感器网络的能量利用效率,并通过与对比算法组的比较证明了算法在能量优化上的有效性。     

浅谈校园网网络性能评估

本文介绍了校园网网络性能评估背景和网络性能指标,针对网络性能指标提出了网络性能评估的技术与方法,并且介绍了如何选择评估工具,为校园网网络性能评估提供了理论依据。     

A modified dynamic surface approach for control of nonlinear systems with unknown input dead zone

This paper focuses on the robust output precise tracking control problem of uncertain nonlinear systems in pure‐feedback form with unknown input dead zone. By designing an extended state observer, the states unmeasurable problem in traditional feedback control is solved, and the lumped uncertainty, which is caused by system unknown functions and input dead zone, is estimated. In order to apply separation principle, finite‐time extended state observer is designed to obtain system states and estimate the lumped uncertainty. Then, by introducing tracking differentiator, a modified dynamic surface control approach is developed to eliminate the ‘explosion of complexity’ problem and guarantee the tracking performance of system output. Because tracking differentiator is a fast precise signal filter, the closed‐loop control performance is significantly improved when it is used in dynamic surface control instead of first‐order filters. The L _∞ stability of the whole closed‐loop system, which guarantees both the transient and steady‐state performance, is shown by the Lyapunov method and initialization technique. Numerical and experiment examples are performed to illustrate our proposed control scheme with satisfactory results. Copyright © 2013 John Wiley & Sons, Ltd.     

Application execution path analysis for the automatic parallelisation of binary codes in the Intel x86 platform

Traditionally, computer programs have been developed using the sequential programming paradigm. With the advent of parallel computing systems, such as multicore processors and distributed environments, the sequential paradigm became a barrier to the utilisation of the available resources, since the program is restricted to a single processing unit. To address this issue, we propose a transparent automatic parallelisation tool with a binary rewriter. The steps of our approach are: the disassembly of the Intel x86 application, its transformation into an intermediary language; the analysis of this intermediary representation to obtain the flow and dependency graphs; the partitioning of the application into parallel units, using the obtained graphs; and, finally, the reassembly of the application back into the original Intel x86 architecture. By transforming the compiled application software, we aim at obtaining a program which can better explore the parallel resources, with no extra effort required from users or developers.