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51.
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). 相似文献
52.
Maria-Jose Escobar Guillaume S. Masson Thierry Vieville Pierre Kornprobst 《International Journal of Computer Vision》2009,82(3):284-301
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. 相似文献
53.
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. 相似文献
54.
55.
在当前的嵌入式设备中.触摸屏作为人机接口得到了广泛的应用.文章讨论了在基于PXA270微处理器的开发平台上使用UCB1400控制芯片完成触摸屏模块的软硬件设计,以及在嵌入式Linux操作系统中的软件驱动程序开发. 相似文献
56.
该文阐述了在Linux下,利用V4L以及ALSA,在普通PC上组建视频音频采集系统以及远程传输的方法。 相似文献
57.
Embedded systems such as PVR, set-top box, HDTV put unique demand on I/O subsystem design. Underlying software, particularly
file system, needs to be elaborately designed so that it can meet tight constraints of consumer electronics platform: performance,
price, reliability, and etc. In this work, we develop state-of-art file system elaborately tailored for A/V workload. There
are two design objectives in our file system: performance and support for logical level abstraction. For performance, we develop
a number of novel features: extent based allocation, single level file structure with block index augmentation scheme, aggressive
free block allocation to minimize disk fragmentation, elaborate file system meta data layout, separation of name space data
and file data and etc. HERMES enables the user to view file as a collection of semantic units (frame or audio samples). HERMES
file system encompasses most of state-of-the-art file system technologies published in preceding works. Via extensive physical
experiment, we verify that HERMES file system successfully addresses the original issues: good scalability, predictable I/O
latency (minimizing variability in I/O latency), efficient disk head movement and etc. This is the result of harmonious effort
of large I/O size, aggressive free block allocation algorithm, data block placement strategy, file organization, layout of
HERMES file system and etc. The result of performance experiments indicate that HERMES file system prototype successfully
meets the file system constraints for high volume and high bandwidth multimedia application. HERMES file system exhibits superior
performance to EXT2 file system (Linux) and XFS file system (SGI).
相似文献
Youjip WonEmail: |
58.
船在海上航行时会随着海浪不停的晃动,船载天线跟随船体晃动则会产生通讯中断,因此采取船载两轴稳定平台来实现天线与船体晃动的隔离,保证船载天线间的通讯质量;文中两轴稳定平台系统采用双闭环控制和积分分离PID控制器实现;文章阐述了船载稳定平台控制系统的工作原理,设计了一款基于P89V51微处理器的两轴稳定平台控制器,并给出了控制器硬件电路的设计原理图;最后按功能实现对软件模块进行了划分和介绍;通过摇摆台模拟试验,该两轴稳定平台控制系统运行可靠,动态精度较高,能确保船载天线之间的正常通讯。 相似文献
59.
This paper presents a performance analysis of nonlinear periodically time-varying discrete controllers acting upon a linear time-invariant discrete plant. Time-invariant controllers are distinguished from strictly periodically time-varying controllers. For a given nonlinear periodic controller, a time-invariant controller is constructed. Necessary and sufficient conditions are given under which the time-invariant controller gives strictly better control performance than the time-invariant controller from which it was obtained, for the attenuation of lp exogenous disturbances and the robust stabilization of lp unstructured perturbations, for all p[1,∞]. 相似文献
60.
Seong S. Chae Janice L. DuBien William D. Warde 《Computational statistics & data analysis》2006,50(12):3531-3546
Distributional and asymptotic results on the moment of Rand's Ck statistic were derived by DuBien and Warde [1981. Some distributional results concerning a comparative statistic used in cluster analysis. ASA Proceedings of the Social Statistics Section, 309–313.]. Based on those results, a method to predict the number of clusters is suggested by applying various agglomerative clustering algorithms. In the procedure, the methods using different indexes are examined and compared based on the concept of agreement (or, disagreement) between clusterings generated by different clustering algorithms on the set of data. Our method having practical generality works better than the other methods and assigns statistical meaning to Ck values in determining the number of clusters from the comparison. 相似文献