基于V4L2的视频设备驱动开发

在嵌入式系统上,特别是系统资源相对较少的情况下,良好的驱动结构设计能够有效地减少驱动的内存和CPU占用量,从而提高系统性能.V4L2是Linux下视频设备驱动开发的新框架,深入分析了V4L2的运行机制,在充分利用其特性的基础上,从减少系统资源消耗和提高驱动性能的角度出发,给出了一套有效的视频设备V4L2驱动开发方法.实验结果表明了该方法的有效性.     

一种改进的数据通信协议设计与实现

在主机与目标机间建立与通信端口无关的命令驱动式数据通信协议,给出数据包格式及命令功能定义。该协议采用分层和模块化设计方法,支持1553B和RS-232 2种通信端口,通过扩展底层通信管理模块可实现对CAN、SPI、SPACEWIRE等总线的支持。SPARC V8存储器加载和下载软件的运行结果验证该协议的正确性,表明其能屏蔽不同通信端口之间的差异性,实现正常的数据传输。     

On the surface area of the -star graph

We present an explicit formula for the surface area of the (n,k)-star graph, i.e., the number of nodes at a certain distance from the identity node in the graph, by identifying the unique cycle structures associated with the nodes in the graph, deriving a distance expression in terms of such structures between the identity node of the graph and any other node, and enumerating those cycle structures satisfying the distance restriction.The above surface area derivation process can also be applied to some of the other node symmetric interconnection structures defined on the symmetric group, when the aforementioned distance expression is available.     

On the decoding of binary cyclic codes with the Newton identities

We revisit in this paper the concept of decoding binary cyclic codes with Gröbner bases. These ideas were first introduced by Cooper, then Chen, Reed, Helleseth and Truong, and eventually by Orsini and Sala. We discuss here another way of putting the decoding problem into equations: the Newton identities. Although these identities have been extensively used for decoding, the work was done manually, to provide formulas for the coefficients of the locator polynomial. This was achieved by Reed, Chen, Truong and others in a long series of papers, for decoding quadratic residue codes, on a case-by-case basis. It is tempting to automate these computations, using elimination theory and Gröbner bases.Thus, we study in this paper the properties of the system defined by the Newton identities, for decoding binary cyclic codes. This is done in two steps, first we prove some facts about the variety associated with this system, then we prove that the ideal itself contains relevant equations for decoding, which lead to formulas.Then we consider the so-called online Gröbner basis decoding, where the work of computing a Gröbner basis is done for each received word. It is much more efficient for practical purposes than preprocessing and substituting into the formulas. Finally, we conclude with some computational results, for codes of interesting length (about one hundred).     

Action Recognition Using a Bio-Inspired Feedforward Spiking Network

We propose a bio-inspired feedforward spiking network modeling two brain areas dedicated to motion (V1 and MT), and we show how the spiking output can be exploited in a computer vision application: action recognition. In order to analyze spike trains, we consider two characteristics of the neural code: mean firing rate of each neuron and synchrony between neurons. Interestingly, we show that they carry some relevant information for the action recognition application. We compare our results to Jhuang et al. (Proceedings of the 11th international conference on computer vision, pp. 1–8, 2007) on the Weizmann database. As a conclusion, we are convinced that spiking networks represent a powerful alternative framework for real vision applications that will benefit from recent advances in computational neuroscience.     

Quadratic optimal neural fuzzy control for synchronization of uncertain chaotic systems

This paper presents a novel quadratic optimal neural fuzzy control for synchronization of uncertain chaotic systems via H^∞ approach. In the proposed algorithm, a self-constructing neural fuzzy network (SCNFN) is developed with both structure and parameter learning phases, so that the number of fuzzy rules and network parameters can be adaptively determined. Based on the SCNFN, an uncertainty observer is first introduced to watch compound system uncertainties. Subsequently, an optimal NFN-based controller is designed to overcome the effects of unstructured uncertainty and approximation error by integrating the NFN identifier, linear optimal control and H^∞ approach as a whole. The adaptive tuning laws of network parameters are derived in the sense of quadratic stability technique and Lyapunov synthesis approach to ensure the network convergence and H^∞ synchronization performance. The merits of the proposed control scheme are not only that the conservative estimation of NFN approximation error bound is avoided but also that a suitable-sized neural structure is found to sufficiently approximate the system uncertainties. Simulation results are provided to verify the effectiveness and robustness of the proposed control method.     

一种数字式DC270V过流保护器的设计

在航空直流供配电领域,高压DC270V电源作为一种新的电能形式得到逐步应用.不同于传统的DC28V系统,高压直流系统无法通过传统断路器的双金属片结构实现线路的过流保护.基于此,提出了一种新的数字式DC270V线路过流保护的方法,实现了电流保护值可调、保护曲线可调的反时限过流保护功能和电流保护值可调、保护时间可调的定时限过流保护功能,并研制出样机.实验结果表明:该样机有效地实现了限定条件下的反时限过流保护和定时限过流保护功能,并且具有良好的使用界面.     

Altera MAX V CPLD的工程设计应用及系统开发

本文阐述了Altera MAX V最小系统从硬件原理图到PCB设计、从软件QuartusII编写VHDL到Modelsim-Al-tera的软件仿真,以及最终的程序下载到开发板上的整个工程设计调试过程,为后续的Altera MAX V工程设计应用提供技术参考和支持.     

峰值电流模升压转换器的动态斜坡补偿电路设计

基于HHNEC 0.35 μm BCD工艺设计了一种应用于峰值电流模升压转换器的动态斜坡补偿电路.该电路能够跟随输入输出信号变化,相应给出适当的补偿量,从而避免了常规斜坡补偿所带来的系统带载能力低及瞬态响应慢等问题.经Cadence Spectre验证,该电路能够达到设计要求.     

MELP低速率语音编码器在DSP上的改进与优化*

在标准混合激励线性预测(MELP)语音编码算法中,对同时含有清音和浊音的混合帧会产生参数估计错误,并且导致合成语音质量的下降。针对这个缺陷提出一种基于过渡帧判决算法的改进MELP模型(M-MELP),提高了参数估计的准确度,保证了合成语音的质量,并结合TMS320C6416数字信号处理器的结构特点,通过改写开源的MELP算法实现M-MELP算法,从程序结构、编译器和代码进行三级优化。相对于单一的优化,能更好的提高程序运行的并行性和存储器的访问效率,从而在基于DSP的嵌入式系统中实现高质量的实时语音编码。