基于改进差别矩阵的属性约简增量式更新算法

针对目前基于差别矩阵的属性约简算法需要耗费大量的时间和空间,粗糙集中求属性核和属性约简更新效率低以及有关属性约简的增量式更新算法目前还比较少等问题,提出了一种基于改进差别矩阵的属性约简增量式更新算法.该算法在更新差别矩阵时,仅须插入某一行及某一列,或删除某一行并修改相应的列,因而可有效地提高核和属性约简的更新效率.然后在分析新增对象x与原决策系统对象的关系的基础上,给出了属性约简增量更新算法.理论与实验分析表明,提出的算法提高了属性约简的更新效率,明显降低了时间和空间复杂度.     

基于差别矩阵的属性核快速更新算法

核求解是粗糙集理论的重要内容之一,尽管在核求解问题上已有大量的研究成果,但有关核更新算法的报道却不多,有人提出一种在对象增加情况下核的增量式更新算法,但未讨论对象动态删除的情况．对此,提出一种基于差别矩阵的属性核快速更新算法——FUAC．该算法在更新差别矩阵时仅需删除某一行及某一列,或插入某一行,因而可有效提高核的更新效率．理论分析表明,该算法是有效可行的．     

一种基于改进差别矩阵的核增量式更新算法

提出一种基于改进差别矩阵的核增量式更新算法,主要考虑对象动态增加情况下核的更新问题．该算法在更新差别矩阵时仅须插入某一行及某一列,或删除某一行并修改相应的列,因而可有效地提高核的更新效率．理论分析和实验结果表明,该算法是有效可行的．     

The integrated display controller (IDC) for VLSI-design workstations

A display controller to accelerate the updating of the frame buffer in raster displays is presented. The advantage of a frame buffer system is the ability to display pictures of any complexity, flicker free. The disadvantage is the great amount of pixel data, which must be updated, when the picture is changed. The Integrated Display Controller (IDC) described in this paper gets its name from the fact that both a pixel plane and a processor are integrated on a single chip. An internal logical unit, a shifter and special memory are provided to process complete rows and columns of pixels, or some part of them in parallel. All operations are performed in one bus cycle, which means that all the pixels addressed in the row or column are modified at the same time. Due to the special organization of the IDC, time consuming operations like block transfer or scrolling can be done significantly faster than in conventional systems. An experimental IDC with a lower screen resolution is developed to demonstrate the feasibility of the design. It is intended for use in VLSI-design workstations, where a great quantity of data has to be manipulated.     

一种基于改进差别矩阵的属性约简增量式更新算法

粗糙集方法提供了一种新的处理不精确、不完全与不相容知识的数学工具.属性约简是粗糙集理论的重要研究内容之一,已有的大多数属性约简算法主要考虑信息系统(或决策表)不变的情况,有关属性约简的增量式更新算法却报道不多.为此,文中提出一种基于改进差别矩阵的属性约简增量式更新算法,主要考虑对象动态增加情况下属性约简的更新问题.该算法可通过快速更新差别矩阵,在动态求解核的基础上,利用原有的属性约简有效地进行属性约简的增量式更新,因而可提高属性约简的更新效率.理论分析表明,该文提出的算法是有效可行的.     

DICE: An Effective Query Result Cache for Distributed Storage Systems

Due to the proliferation of Internet and Intranet, the distributed storage systems have received a lot of attention. These systems span a large number of machines and store huge amount of data for a lot of users. In the distributed storage systems, a row can be directly accessed using a row key. We concentrate on a problem of efficient processing of queries whose predicate is on a column but not a row key. In this paper, we present a cache management technique, called DICE which maintains query results of range queries to support the next range queries. To accelerate the search time of the cached query results, we use modified Interval Ski Lists. In addition, we devise a novel cache replacement policy since DICE maintains an interval rather than a data item. Since our cache replacement policy considers the properties of intervals, our proposed technique is more efficient than traditional buffer replacement algorithms. Our experimental result demonstrates the efficiency of our proposed technique.     

基于对象角色的高精度缓存替换算法*

现有的Web缓存器的实现主要是基于传统的内存缓存算法,由于Web业务请求的异质性,传统的替换算法不能在Web环境中有效工作。研究了Web缓存替换操作的依据,分析了以往替换算法的不足,考虑到Web文档的大小、访问代价、访问频率、访问兴趣度以及最近一次被访问的时间对缓存替换的影响,提出了Web缓存对象角色的概念,建立了一种新的基于对象角色的高精度Web缓存替换算法(ORB算法);并以NASA和DEC的代理服务器数据为例,将该算法与LRU、LFU、SIZE、Hybrid算法进行了仿真实验对比,结果证明,ORB算     

深入剖析ADO.NET数据集的批处理更新机制

数据集是ADO．NET技术的核心部分,本文通过对数据表三种更新过程的详细介绍,深入剖析了数据表中数据行的数据版本和状态行的含义与作用,最后介绍了数据集批处理更新在数据库应用开发中如何通过视图实现对数据源基本表的更新。     

高效均值滤波算法*

为了提高现有均值滤波算法的速度,减少冗余操作,提出了一种高效的均值滤波算法。首先建立一个辅助数组,结合滤波窗口在按行滑动时相邻窗口之间的递归关系和按列移动时相邻两行对应的辅助数组之间的递归关系,设计出更新辅助数组元素和新窗口中心点对应均值的递归式,根据这两个递归式,设计出了高效的均值滤波算法。理论分析表明该算法极大地减少了冗余操作,且算法效率不受窗口大小变化的影响。实验结果证明,在滤波效果一致的前提下,本算法比现有快速均值滤波算法更高效。     

A quasi-Newton method with sparse triple factorization for unconstrained minimization

A new quasi-Newton method for unconstrained minimization is presented. It uses sparse triple factorization of an approximation to the sparse Hessian matrix. At each step a new column and a corresponding row of the approximation to the Hessian is determined and its triple factorization is updated. Our method deals with the same updating problem as in J. Bräuninger's paper [2]. However, we make use of a rank-two instead of a rank-one updating scheme. Our method saves over half the number of operations required in J. Bräuninger's method. Moreover, our method utilizes the sparsity and, therefore, only the nonzero entries of the factors need to be stored. The positive definiteness can be preserved easily by taking suitable precautions. Under reasonable conditions our method is globally convergent and locally superlinearly evenn-step ρ-order convergent.     

Graphical control systems and multiple displays

Control systems are considered which require updating of a large number of graphics displays of system and subsystem configurations. All of the displays are to be updated and to be shown on a CRT screen upon user demand, within a limited time period. Many models for evaluating system performance are given for different hardware combinations. The problem was initially studied at the Goddard Space Flight Center of the National Aeronautics and Space Administration in Greenbelt, Maryland with regard to ground control systems for spacecraft.     

Nonnegative matrix factorization by joint locality-constrained and <Emphasis Type="Italic">ℓ</Emphasis><Subscript>2,1</Subscript>-norm regularization

Nonnegative matrix factorization has been widely applied recently. The nonnegativity constraints result in parts-based, sparse representations which can be more robust than global, non-sparse features. However, existing techniques could not accurately dominate the sparseness. To address this issue, we present a unified criterion, called Nonnegative Matrix Factorization by Joint Locality-constrained and ? _2,1-norm Regularization(NMF2L), which is designed to simultaneously perform nonnegative matrix factorization and locality constraint as well as to obtain the row sparsity. We reformulate the nonnegative local coordinate factorization problem and use ? _2,1-norm on the coefficient matrix to obtain row sparsity, which results in selecting relevant features. An efficient updating rule is proposed, and its convergence is theoretically guaranteed. Experiments on benchmark face datasets demonstrate the effectiveness of our presented method in comparison to the state-of-the-art methods.     

中文搜索引擎分块倒排索引存储模式

针对开源搜索引擎ASPSeek中的倒排索引的内部结构和访问模式,抽象出了倒排索引的形式化定义。为解决ASPSeek倒排索引更新困难和直接采用操作系统文件缓冲访问机制带来的效率问题,以125万张中文农业网页为样本,结合其特点,提出了一种块大小可变的分块倒排索引存储模式和基于CLOCK替代策略的专用缓冲管理机制。实验结果表明在禁用和启用缓冲的情况下,分块访问模式检索效率都优于ASPSeek。在启用缓冲并使用16万中文词条或5万高频中文词条作为测试集合的条件下,分块存储模式在访问倒排索引100万次后的检索时间趋于常量,即使以全部的827309个词条作为测试集合的条件下,分块存储模式在访问倒排索引200万次后的检索时间趋于收敛。     

改进的混合蛙跳算法及其在多阈值图像分割中的应用

针对混合蛙跳算法(Shuffled Frog Leaping Algorithm,SFLA)存在的计算复杂度高、优化效率不理想等问题,提出了一种改进的混合蛙跳算法(Improved Shuffled Frog Leaping Algorithm,ISFLA)。在原始 SFLA的基础上进行如下改进:首先,将其中每次只更新组内最差青蛙的方式改为更新组内所有青蛙的方式,这既增大了获得优质解的概率,又省去了调整组内迭代次数的步骤,从而提升了优化效率和可操作性;其次,将基于局部最优更新的方法和基于全局最优更新的方法融合为一种混合扰动更新方法,从而避免了复杂条件的选择步骤,进一步提升了优化效率;最后,去掉随机更新方式,以免优质解被破坏,从而提高了整体的优化性能。将 ISFLA 用于 CEC2005和CEC2015连续基准函数的优化测试和基于Renyi 熵的灰度和彩色图像分割的多阈值选择实验中,结果表明,与 SFLA 和state-of-the-art的LSFLA 相比,ISFLA 具有更高的优化效率,更适用于多阈值图像分割的阈值选择。     

基于51单片机的多色点阵显示系统设计

本设计以51系列单片机为主控芯片,通过行列驱动,控制16×16的双色点阵,构成了一款多色点阵显示系统。该系统可显示图形或文字,显示内容能够移动,并有三种不同颜色的变化。电路工作时采用了动态扫描的方式,行驱动使用了373锁存器,列驱动使用了154译码器和245驱动芯片,可以节省单片机I/O口。电路还有串行口通信功能,连接上位机进行实时显示信息更新。显示屏幕可以根据需要进行扩展。     

A new driving method to compensate for row‐line signal‐propagation delays in an AMLCD

Abstract— The row‐line and data‐line that make up of a TFT‐LCD panel can be modeled as a distributed resistance and capacitance network. As TFT‐LCD panels become larger and provide higher resolution, the induced signal propagation delay time from the row and column lines become an appreciable part of the line time. In particular, the row signal‐propagation delay time is traditionally accommodated by waiting for the worst‐case propagation time before the start of a new line. This conventional method, however, reduces the subpixel charging time. A new driving method, Horizontal Line Delay Compensation (H‐LDC), has been implemented and verified to compensate for row‐line propagation delay. The benefit of longer subpixel charging time is of particular interest to large‐area high‐resolution fast‐refresh‐rate LCD TVs.     

一种消除CMOS图像传感器行噪声的时序

为了消除CMOS图像传感器中随机变化的行噪声,在传统相关双采样的基础上,提出了一种新的读出时序.该时序采用行相关双采样方法,同时对相邻的两行像素进行操作,在采集图像信号的同时,把行随机噪声也采样到电容上,进行全差分操作,将行噪声消除.仿真结果表明:这种读出方法可以将行随机噪声大幅减小,经放大器放大32倍后噪声仍小于AD...     

Newsvendor problems with demand forecast updating and supply constraints

This study investigates an extension of the newsvendor model with demand forecast updating under supply constraints. A retailer can postpone order placement to obtain a better demand forecast with a shorter supply lead time. However, the manufacturer would charge the retailer a higher cost for a shorter lead time and set restrictions on the ordering times and quantities. This prevents retailers from taking full advantage of demand forecast updating to improve profits. In studying the manufacturer-related effects, two supply modes are investigated: supply mode A, which has a limited ordering time scale, and supply mode B, which has a decreasing maximum ordering quantity. For supply mode A, it is proven under justifiable assumptions that a retailer should order either as early or as late as possible. For supply mode B, an algorithm is proposed to simplify the ordering policy by appropriately relaxing the ordering quantity restrictions. Numerical analysis is conducted to investigate the influence of product and demand parameters on the value of demand forecast updating in the two supply modes. A comparison of the different supply scenarios demonstrates the negative effects of increased purchasing cost and ordering time and quantity restrictions when demand forecast updating is implemented.     

FAULT-TOLERANT MULTI-AGENT EXACT BELIEF PROPAGATION

Multiply sectioned Bayesian networks (MSBNs) support multi-agent probabilistic inference in distributed large problem domains, where agents (subdomains) are organized by a tree structure (called hypertree). In earlier work, all belief updating methods on a hypertree are made of two rounds of propagation, each of which is implemented as a recursive process. Both processes need to be started from the same designated (root) hypernode. Agents perform local belief updating at most in a partial parallel manner. Such methods may not be suitable for practical multi-agent environments because they are easy to crush for the problems happened in communication or local belief updating. In this paper, we present a fault-tolerant belief updating method for multi-agent probabilistic inference. In this method, multiple agents concurrently perform exact belief updating in a complete parallel. Temporary problems happened from time to time at some agents or some communication channels would not prevent agents from eventually converging to the correct beliefs. Permanently disconnected communication channels would not keep the properly connected portions of the system from appropriately finishing their belief updating within portions. Compared to the previous traversal-based belief updating, the proposed approach is not only fault-tolerant but also robust and scalable.     

一个前向安全无证书代理签名方案的安全性分析*

对一个前向安全无证书代理签名方案进行分析,指出这个方案既不具有不可伪造性,也不具有前向安全性。证明了该方案对于公钥替换攻击是不安全的,即敌手通过替换原始签名者和代理签名者的公钥可以伪造该代理签名者对任意消息的代理签名,给出了伪造攻击方法。指出该方案不具备前向安全性的原因,即该签名方案的代理密钥更新算法没有利用时段标识,代理签名没有明确包含时段信息。