Harris算法硬件加速设计

针对序列图像实时边缘和角点检测应用需求,对Harris算法进行了硬件加速设计,提出了一种内嵌并行运算的流水线结构。采取分解简化高斯模板、流水实现复杂计算、缓存灰度数据并并行计算一阶差分及其乘积等措施提高算法的实时处理能力,减少硬件资源消耗。ModeISim仿真结果和ISE综合报告显示,与常规方法相比,该设计在性能、速度和硬件资源消耗方面均表现较好,在实时图像处理应用领域有较好的实用价值。     

Molecular Computation and Evolutionary Wetware: A Cutting-Edge Technology for Artificial Life and Nanobiotechnologies

Focusing on the new frontiers opened by the integration of artificial life and nanobiotechnologies, this paper reviews mainstream biomolecular computation from the viewpoint of an information processing mechanism, computing methods, and problem-solving algorithms. We also discuss evolutionary wetware as a tool for unconventional computing, inspired by biomolecular systems in nature. Biomolecular computation uses a different paradigm of computing than that of the semiconductor computer. It includes several branches based on different molecular materials or molecular structures. Wetware can be used to demonstrate molecular evolution by engineered operations in test tubes. This makes evolutionary wetware capable of bridging the two domains of molecular computation and artificial life so that molecular information processing methods can be extended from carrying out computational tasks to modeling scalable complex systems. From a systematic study of nanobiomachines, we expect to designate models of artificial life, and to search for a novel methodology of nanobioICT (Information and Communication Technology) in the near future     

一种基于互谱思想的STAP降维方法

全空时自适应处理在工程实现中因计算量大、独立同分布样本难以获取等问题而使应用受到一定限制,在传统互谱法以及杂波协方差矩阵特征向量分解法两种空时自适应处理降维算法的基础上,提出了一种新的基于互谱思想的协方差矩阵特征向量分解算法,该方法根据不同的互谱值对应的信噪比损失的大小不同这一原理构造降维矩阵,有效地降低了运算量,并能够形成较好的杂波滤波凹口,实现了滤除杂波的性能,文中经过实验仿真验证了该方法的有效性。     

Wireless and cellular architecture and services

Cellular architecture partitioning can improve the performance of telecommunications systems. The model proposed by the author allows for changing the cell size for different services and the number of users. The cell size that will ensure the best possible performance and quality of service can be derived by the model. The main task of a telecommunication system is call processing. This includes identifying incoming calls, establishing a communication path for the duration of the connection, and disconnecting the call after the conversation has ended. Call processing uses different components of the software architecture and involves processes and messages performing different functions and accessing various resources. In addition, the system requires administration and maintenance that also involves processes using different resources     

一种新的Jakes模型参数计算方法

本文分析了小尺度无线衰落信道的理论参考模型—Clark模型,比较了两种较为重要的确定性仿真模型的参数计算方法—精确多普勒扩展法（MEDS）和随机精确多普勒扩展法（R_MEDS）,提出了一种新的用于仿真平坦衰落信道Jakes模型的参数计算方法,即在MEDS的基础上对离散多普勒频率引入随机抖动。仿真数据和图形表明,在模型复杂度较低的情况下,新的信道模型的自相关和互相关特性较R_MEDS有很大改善,而且与原始MEDS相比,新模型多普勒频率为随机变量,可以有效仿真瑞利衰落、多个不相关的瑞利衰落和频率选择性衰落信道等,并且可以结合工程需要设定随机抖动幅度,保证了衰落信道的不相关性和遍历性的有机统一。      

Suboptimal method for time-space signal processing in airborne radar

A new suboptimal method for time-space signal processing in airborne phased array radar is proposed which can significantly reduce the necessary computation compared with other optimal or suboptimal methods. The numerical results obtained from simulation illustrate that this method possesses ideal performance and is a realisable scheme for real-time processing.<>     

A deterministic digital simulation model for Suzuki processes withapplication to a shadowed Rayleigh land mobile radio channel

We present a novel computer simulation model for a land mobile radio channel. The underlying channel model takes for granted non-frequency-selective fading but considers the effects caused by shadowing. For such a channel model we design a simulation model that is based on an efficient approximation of filtered white Gaussian noise processes by finite sums of properly weighted sinusoids with uniformly distributed phases. In all, four completely different methods for the computation of the coefficients of the simulation model are introduced. Furthermore, the performance of each procedure is investigated on the basis of two quality criteria. All the presented methods have in common the fact that the resulting simulation model has a completely determined fading behavior for all time. Therefore, the simulation model can be interpreted as a deterministic model that approximates stochastic processes such as Rayleigh, log-normal, and Suzuki (1977) processes     

A Comparison of Three Methods for Calculating Lower Confidence Limits on System Reliability Using Binomial Component Data

The Maximus, bootstrap, and Bayes methods can be useful in calculating lower s-confidence limits on system reliability using binomial component test data. The bootstrap and Bayes methods use Monte Carlo simulation, while the Maximus method is closed-form. The Bayes method is based on noninformative component prior distributions. The three methods are compared by means of Monte Carlo simulation using 20 simple through moderately complex examples. The simulation was generally restricted to the region of high reliability components. Sample coverages and average interval lengths are both used as performance measures. In addition to insights regarding the adequacy and desirability of each method, the comparison reveals the following regions of superior performance: 1. The Maximus method is generally superior for: a) moderate to large series systems of reliable components with small quantities of test data per component, and b) small series systems of repeated components. 2. The bootstrap method is generally superior for highly reliable and redundant systems. 3. The Bayes method is generally superior for: a) moderate to large series systems of reliable components with moderate to large numbers of component tests, and b) small series systems of reliable non-repeated components.     

分层异构信号处理平台调度方法研究

异构多处理器的高效性和可靠性能够满足日趋复杂的信号处理任务需求,因此分层异构系统已成为信号处理平台的发展趋势.为提高平台强实时性并解决高吞吐量的问题,文中对分层异构信号处理平台的软硬件模块及架构进行了研究,并采用有向无环图对组件任务及硬件资源进行建模.将已提出的调度算法按照任务类型、调度目标、调度过程和研究方法进行分类...     

Transmitter-based multiuser interference rejection for thedown-link of a wireless CDMA system in a multipath environment

In wireless code division multiple access (CDMA) communications systems, there has been interest in processing the transmitted down-link signal in order to shift signal processing to the transmitter where power and computational resources are plentiful, thus simplifying receiver operation and reducing the power it requires. Multiuser interference (MUI) and multipath effects observed by the receiver are anticipated and suppressed at the transmitter; channel equalization and multiuser detection are therefore not required. This paper introduces two methods that are able to combat both degradations, yet allow the receiver to remain as simple as a single user receiver for a perfect channel. For mild multipath channels, the performance of the algorithms is excellent, within a few decibels of the single user ideal channel case, at the cost of additional computation at the base station at which complete knowledge of the channels and the receiver codewords is required. One method, the decorrelating prefilter, is most flexible and applicable to existing systems yet less powerful than other previously published methods. The second, the jointly optimized sequences algorithm, has a performance on average superior to published methods. In addition to theoretical analysis and simulation of the algorithms' potential, these algorithms have also been implemented and tested on a software radio testbed and experimental data are shown. The jointly optimized sequences performed particularly well even in severe multipath and multiuser interference environments     

A hybrid approach for Structural Monitoring with self-organizing multi-agent systems and inverse numerical methods in material-embedded sensor networks

One of the major challenges in Structural Monitoring of mechanical structures is the derivation of meaningful information from sensor data. This work investigates a hybrid data processing approach for material-integrated structural health and load monitoring systems by using self-organizing mobile multi-agent systems (MAS), and inverse numerical methods providing the spatial resolved load information from a set of sensors embedded in the technical structure with low-resource agent processing platforms scalable to microchip level, enabling material-integrated real-time sensor systems. The MAS is deployed in a heterogeneous environment and offers event-based sensor preprocessing, distribution, and pre-computation. Inverse numerical approaches usually require a large amount of computational power and storage resources, not suitable for resource constrained sensor node implementations. Instead, the computation is partitioned into spatial off-line (outside the network) and on-line parts, with on-line sensor processing performed by the agent system. A unified multi-domain simulation framework is used to profile and validate the proposed approach.     

Real-time simulation of dynamic systems on a pyramid architecture

The applicability of a pyramid architecture, the GAM-2 pyramid computer, for the real-time simulation of dynamic systems is demonstrated. The architecture of the computer and the manner in which data are exchanged between processing elements are discussed. The author focuses on how the differential equations and the various computational units of the integration algorithm can be partitioned among the processing elements at the different levels in the pyramid in order to minimize the computation and data transfer times. The required computation time of an integration cycle is evaluated, and conclusions are drawn concerning the efficiency of using the GAM-2 pyramid and similar structures for digital simulation     

基于SPW的PSK数字通信系统仿真与分析

在现代通信系统设计中,计算机仿真设计可以快速构建系统模型,降低开发成本和周期,实现性能评估、系统优化的目的.讨论了数字信号处理和通信系统仿真设计软件SPW的功能、应用,依据PSK通信系统原理,设计出了基于SPW的BPSK系统模型.调试、仿真获得了系统关键信号的时域波形、眼图及功率谱,结果表明仿真设计满足系统性能要求.     

MIMO雷达收发两级STAP 原理与性能讨论

提出了一种基于多输入多输出雷达的收发两级空时自适应处理(STAP)算法。收发两级STAP 与收发联合STAP 不同在于:分别对等效发射端与接收端进行空时处理,从而达到降低运算量效果。文中给出收发两级STAP 所构造的协方差矩阵与收发联合STAP 协方差矩阵关系,并且给出输出信杂噪比(SCNR)表达式。从仿真结果看,收发两级法SCNR 性能与收发联合STAP 相近,且计算量有明显降低。此外,收发两级STAP 也可应用到收发联合降维算法中,得到与收发联合降维算法一样的性能,且运算量进一步降低。     

Early Stage Automatic Strategy for Power-Aware Signal Processing Systems Design

Complexity management, portability and long term adaptivity are common challenges in different fields of embedded systems, normally colliding with the needs of efficient resource utilization and power balance. Image/signal processing systems, though required to offer a large variety of complex functions, have also to deal with battery-life limitations. Wearable signal processing systems, for example, should provide high performance and support new generation standards without compromising their portability and their long-term usability. These constraints challenge hardware designers: early stage trade-off analysis and power management automated techniques are helpful to guarantee a reasonable time-to-market. In the field of video codec specifications, the MPEG standard known as Reconfigurable Video Coding (RVC) framework addresses functional complexity and adaptivity leveraging on the intrinsic modularity of the dataflow model of computation, but it still lacks in offering power management support. The main contribution of this work is providing an automatic early-stage power management methodology to be adopted within the MPEG-RVC context. Starting from different high-level specifications, our mapping methodology identifies directly on the high-level models disjointed homogeneous logic clock regions, where the platform resources can be enabled/disabled together without affecting the overall system performance. To extend its usability to the RVC community, we have integrated this methodology within the Multi-Dataflow Composer (MDC) tool. MDC is a tool for on-the-fly reconfigurable signal processing platforms deployment. In this paper, we extended MDC to address power-aware multi-context systems. To prove the effectiveness of our work, a coprocessor for image and video processing acceleration has been assembled. This latter has been synthesized on a 90 nm ASIC technology, where demonstrated up to 90 % of reduction in the dynamic power consumption on different dataflow-intensive applications. The coprocessor has been implemented also on FPGA, confirming, partially, the benefits of adopting the proposed methodology.     

Simulation of optical remote sensing systems

Research on understanding the remote-sensing process as a system and investigating the interrelated effects of various parameter is described. A system model for the simulation of remote-sensing systems is presented. The system is divided into three parts: the scene, the sensor, and the processing algorithms. Models are presented and implemented for these component systems. Validation of the system model is considered over a specific test site. Results of the simulation for various scene and sensor configurations are included. Results of applying the model to various system configurations using simulated Landsat sensors are then presented to show how the simulation can be used to investigate the interrelated effects of system parameters.<>     

一种弱信号检测新方法分析

通过计算机仿真分析一种基于频域积累和小波变换相结合的弱信号监测方法,仿真在Matlab上完成。分别分析小波变换和频域积累用于弱信号处理的去噪效果。仿真表明,小波变换对信噪比很低的信号去噪效果较差,频域积累需要较长的数据采集时间,会使信号处理的实时性变差。在此基础上,提出将两种方法结合起来使用,先用频域积累将信噪比提高,再用小波变换进一步去噪,从而形成了一种新的弱信号检测方法,该方法既可有效去噪,实时性也较频域积累有很大改善。     

A comparison of load balancing techniques for scalable Web servers

Scalable Web servers can be built using a network of workstations where server capacity can be extended by adding new workstations as the workload increases. The topic of our article is a comparison of different method to do load-balancing of HTTP traffic for scalable Web servers. We present a classification framework the different load-balancing methods and compare their performance. In addition, we evaluate in detail one class of methods using a prototype implementation with instruction-level analysis of processing overhead. The comparison is based on a trace driven simulation of traces from a large ISP (Internet Service Provider) in Norway. The simulation model is used to analyze different load-balancing schemes based on redirection of request in the network and redirection in the mapping between a canonical name (CNAME) and IP address. The latter is vulnerable to spatial and temporal locality, although for the set of traces used, the impact of locality is limited. The best performance is obtained with redirection in the network     

A generalized framework for hybrid simulation of multi-component structures using iterative field refinement

When applying computational simulation techniques to scattering or radiation problems, it is often possible to decompose a complicated geometry into simpler elemental structures (i.e., a helicopter rotor system into its individual blades). By then simulating each component separately, a given problem can be decomposed into smaller and more manageable components, as long as account is taken of the coupling between each component. To implement such coupling, this paper describes a generalized iterative field refinement (IFR) framework, and demonstrates how it can be used as a basis for many hybrid approaches. Within this framework, IFR can also be used to accelerate simulation of geometries made up of rotated, translated, reflected, or replicated versions of a given structure. Several examples are given to show that an approach built around IFR reduces total computation time while allowing the combination of different analysis methods in treating each of the separate components comprising the structure.