一种有效的数据管理技术

本文在传统的数据库查询方法的基础上介绍了数据库的查询方法;借鉴Ｈａｓｈ 表和Ｈａｓｋ 树的一些基本思想,对数据查询的方法进行了改进;提出了对大数据量的数据库进行快速查询的一种方法。     

An Effective Technique for Subpixel Image Registration Under Noisy Conditions

This paper proposes an effective higher order statistics method to address subpixel image registration. Conventional power spectrum-based techniques employ second-order statistics to estimate subpixel translation between two images. They are, however, susceptible to noise, thereby leading to significant performance deterioration in low signal-to-noise ratio environments or in the presence of cross-correlated channel noise. In view of this, we propose a bispectrum-based approach to alleviate this difficulty. The new method utilizes the characteristics of bispectrum to suppress Gaussian noise. It develops a phase relationship between the image pair and estimates the subpixel translation by solving a set of nonlinear equations. Experimental results show that the proposed technique provides performance improvement over conventional power-spectrum-based methods under different noise levels and conditions.     

基于硬件实现的用于定长匹配的PATRICIA算法

PATRICIA算法是一种经典的信息检索算法,但是插入性能差、硬件实现困难．研究发现,PATRICIA算法在用于定长匹配时如果不保持NBT值的有序性,可以有效地降低硬件设计复杂度,提高插入性能．提出了一种易于硬件实现的定长匹配PATRICIA算法,证明了该算法是时间性能最优的二叉trie算法．针对状态检测技术中的状态表操作,设计了专用硬件结构实现该算法．理论和实验结果表明,该算法易于硬件实现,能够有效地对千兆网络环境的状态表进行操作．     

A Two-Pass Hardware-Based Method for Hierarchical Radiosity

Finite elements methods for radiosity are aimed at computing global illumination solutions efficiently. However these methods are not suitable for obtaining high quality images due to the lack of error control. Two-pass methods allow to achieve that level of quality computing illumination at each pixel and thus introducing a high computing overhead. We present a two-pass method for radiosity that allows to produce high quality images avoiding most of the per-pixel computations. The method computes a coarse hierarchical radiosity solution and then performs a second pass using current graphics hardware accelerators to generate illumination as high definition textures.     

The Need for Fast Communication in Hardware-Based Speculative Chip Multiprocessors

Chip-multiprocessor (CMP) architectures are a promising design alternative to exploit the ever-increasing number of transistors that can be put on a die. To deliver high performance on applications that cannot be easily parallelized, CMPs can use additional support for speculatively executing the possibly data-dependent threads of an application. For cross-thread dependences that must be handled dynamically, the threads can be made to synchronize and communicate either at the register level or at the memory level. In the past, it has been unclear whether the higher hardware cost of register-level communication is cost-effective. In this paper, we show that the wide-issue dynamic processors that will soon populate CMPs, make fast communication a requirement for high performance. Consequently, we propose an effective hardware mechanism to support communication and synchronization of registers between on-chip processors. Our scheme adds enough support to enable register-level communication without specializing the architecture toward speculation much. Finally, our scheme allows the system to achieve near ideal performance.     

指导cache静态划分的程序性能profiling优化技术

对于共享cache的多核处理器,如何管理好各个核对cache的利用,对于充分发挥多核处理器性能是很关键的问题.目前采用的cache替换方法程序间会出现性能干扰,cache静态划分技术则是通过为同时运行的程序分配不同的空间来解决性能干扰问题.为了给程序分配合适大小的cache空间,需要对程序进行性能profiling,即事先多遍运行收集程序在各种cache容量下的性能数据,这种性能profiling方法开销巨大,影响实用.为了解决性能profiling需要多遍运行程序的问题,提出了只需单遍运行的程序性能profiling优化技术.该技术利用在线的phase分析技术识别程序的运行阶段,避免对相同阶段的重复profiling;同时分析程序各phase的性能同cache容量变化的关系趋势,对于性能不敏感的容量变化则不进行profiling,降低开销.在程序运行结束后通过程序各phase在cache各种容量下的性能来估计程序在各容量下的整体性能,以指导cache静态划分.实验表明,该技术的开销仅为7%,而该方法指导的cache划分比未划分时有8%的性能改进,同多遍运行的程序性能profiling指导的cache划分性能相比仅有1%的下降.     

An Improved Attention and Hybrid Optimization Technique for Visual Question Answering

Neural Processing Letters - In Visual Question Answering (VQA), an attention mechanism has a critical role in specifying the different objects present in an image or tells the machine where to...     

控制流路径敏感的深层代码优化技术

软件规范巾的函数凋用约定指出,caller和callee都需要保存函数调用前后的程序状态。根据数据流分析和过程间分析,caller和callee会保存和恢复的程序状态有不同的分工。数据流分析方法在决定对callee-savc的寄存器是否要保存恢复时是从理论上在函数的入口保存寄存器状态而在函数的出口恢复寄存器状态,然而在特定控制流路径上并没有对一些保存的全局寄存器的状态进行修改,所以这些控制流路径上的寄存器保存恢复实际上是冗余的。该文提出了一种简单快捷的反向数据流分析方法,对特定控制流路径上的callee—save的寄存器恢复指令进行选择性优化,从而使特定控制流路径上的代码得到有效的优化,特别足对热控制流路径和短路径,提出的优化方法显得特别重要。     

一种模糊Petri网参数优化的有效方法

本文根据模糊Petri网运行时连续性的特点,以蚁群算法为基础,提出了一种带交叉、变异因子的模糊Petri网参数值寻优的有效方法。该方法先用分层思想建立无环路的FPN模型,然后把它转化为类前向神经网络以确定输入—输出层关系,并将网络中各参数的值域均分为10等份,在图形中用10个城市来表示,再用蚁群算法进行路径的寻优,寻优后,在蚁群选定的值域上产生具体的分量解,最后由误差函数确定是否需要重新寻优。仿真程序实例表明经蚁群优化算法训练出的参数正确率较高,且不依赖于经验输入数据。     

An Optimization Technique for Solving a Class of Ridge Fuzzy Regression Problems

Neural Processing Letters - In this paper, a hybrid scheme based on recurrent neural networks for approximate coefficients (parameters) of ridge fuzzy regression model with LR-fuzzy output and...     

一种模糊Petri网参数优化的有效方法

本文根据模糊Petri网运行时连续性的特点,以蚁群算法为基础,提出了一种带交叉、变异因子的模糊Petri网参数值寻优的有效方法。该方法先用分层思想建立无环路的FPN模型,然后把它转化为类前向神经网络以确定输入—输出层关系,并将网络中各参数的值域均分为10等份,在图形中用10个城市来表示,再用蚁群算法进行路径的寻优,寻优后,在蚁群选定的值域上产生具体的分量解,最后由误差函数确定是否需要重新寻优。仿真程序实例表明经蚁群优化算法训练出的参数正确率较高,且不依赖于经验输入数据。     

RCC-Full: An Effective Network for Parallel Computations

A new interconnection network is proposed for the construction of a massively parallel computer system. The systematic construction of this interconnection network, denoted RCC-FULL, is performed by methodically connecting together a number of basic atoms where a basic atom is a set of fully interconnected nodes. Key communication characteristics are derived and evaluated for RCC-FULL and efficient routing algorithms, which need only local information to route messages between any two nodes, are also derived. AnO(log (N)) sorting algorithm is shown for RCC-FULL and RCC-FULL is shown to emulate deterministically the CRCW PRAM model, with onlyO(log (N)) degradation in time performance. Finally, the hardware cost for the RCC-FULL is estimated as a function of its pin requirements and compared to that of the binary hypercube and most instances of RCC-FULL have substantially lower cost. Hence, RCC-FULL appears to be a particularly effective network for PRAM emulation, and might be considered as a universal network for future supercomputing systems.     

Profiling and evaluating hardware choices for MapReduce environments: An application-aware approach

The core business of many companies depends on the timely analysis of large quantities of new data. MapReduce clusters that routinely process petabytes of data represent a new entity in the evolving landscape of clouds and data centers. During the lifetime of a data center, old hardware needs to be eventually replaced by new hardware. The hardware selection process needs to be driven by performance objectives of the existing production workloads. In this work, we present a general framework, called Ariel, that automates system administrators’ efforts for evaluating different hardware choices and predicting completion times of MapReduce applications for their migration to a Hadoop cluster based on the new hardware. The proposed framework consists of two key components: (i) a set of microbenchmarks to profile the MapReduce processing pipeline on a given platform, and (ii) a regression-based model that establishes a performance relationship between the source and target platforms. Benchmarking and model derivation can be done using a small test cluster based on new hardware. However, the designed model can be used for predicting the jobs’ completion time on a large Hadoop cluster and be applied for its sizing to achieve desirable service level objectives (SLOs). We validate the effectiveness of the proposed approach using a set of twelve realistic MapReduce applications and three different hardware platforms. The evaluation study justifies our design choices and shows that the derived model accurately predicts performance of the test applications. The predicted completion times of eleven applications (out of twelve) are within 10% of the measured completion times on the target platforms.     

有效消减测试成本的并行技术分析

文章通过定量分析指出,并行测试不仅降低了ATE系统的设备投资,而且能够消减测试环节中各项成本因素,因而比之低成本ATE,是更为显著、有效的测试成本消减方法。文章还指出,并行测试最佳站点数相对独立于ATE设备成本、运行成本、产品的合格率以及其它多种限制因素,若设备中可用的独立资源有限,就会降低测试的并行度,从而导致部分测试顺序执行,并行测试的成本优势将迅速消失。     

SQL事件探查与跟踪技术在数据库中的应用

本文通过对SQL Server profile的基本功能的了解及事件探查与跟踪技术在数据库中的应用,阐明了SQL server profile在数据库系统中的重要作用。     

一种高效的图像匹配算法

兼顾算法的精度和效率两个方面,基于图像特征的图像匹配算法,逐渐成为众多学者研究的热点.文中提出了将多分辨率和极线约束与相关法相结合的图像匹配方法.该方法采用金字塔分层和极线约束来弥补相关匹配带来运算量大的不足,克服了图像匹配中精度低和速度慢的缺点.通过实验验证该方法不仅能够有效地缩短匹配时间,还能达到较高的匹配精度.     

Hardware Atomicity: An Effective Abstraction for Reliable Software Speculation

Technology trends and shrinking power envelopes have forced microprocessor designers to focus on hardware techniques that efficiently improve single-thread performance without superlinear increases in power and silicon area. In this article, we identify hardware atomic execution - the execution of a region of code completely or not at all - as such a feature for simplifying existing and enabling new speculative compiler optimizations. Specifically, we propose that microprocessors expose atomic execution as a hardware primitive to the compiler. Doing so lets the compiler generate a speculative version of the code where infrequently executed code paths are removed.     

CBR: An Effective Clustering Approach for Time Series Events

Neural Processing Letters - As technology advances, a large number of time series data have emerged in all walks of life. Clustering is a key technique for analysing time series data. However, most...     

OSOD:一个油田开发规划优化决策系统

油田开发规划是一项复杂的系统工程,在一定投资下,要使得利润最大、产量最大,并且尽量降低成本,需要通过数学规划的方法进行科学合理的决策。为此,该文开发了油田开发规划优化决策系统,可以作为长期或短期油田开发规划的决策工具。