分布式数据库复制实施策略中的冲突预防和解决

复制是分布式数据库实施策略中的重要一种，它能大大提高各结点的自治性，同时保证各结点数据副本之间的松散一致性，然而各结点自主的数据操作之间很可能发生冲突。针对这种情况，提出了设计分布式数据库时就积极地采取措施尽可能预防冲突发生；当冲突发生时，采用合理的策略来解决冲突。最后，以SQL Server2000为例来说明这种思想的具体应用。     

VSAT系统改进隔离型随机N叉树形冲突分解算法研究

In this paper, a new random N-ary tree collision resolution algorithm of improved isolation type is used to analyze the packet collision resolution in VSAT random multiple access system. The analytic formulae of the mean slot number which is needed by packet collision resolution and the average throughput for dynamic and static system are given, the more results are verified by experiments.     

基于小波多分辨率分析的多通道遥感图像数据融合方法及实现

对同一目标的多波谱遥感图像进行融合、是富集有用信息、提高图像空间分辨率和解释水平的有效手段，本文提出了基于小波多分辨率分析的多通道遥感图像数据融合的原理、方法及实现过程，实例分析其结果良好。     

Concepts and Application of Time-Limiters to High Resolution Schemes

A new class of implicit high-order non-oscillatory time integration schemes is introduced in a method-of-lines framework. These schemes can be used in conjunction with an appropriate spatial discretization scheme for the numerical solution of time dependent conservation equations. The main concept behind these schemes is that the order of accuracy in time is dropped locally in regions where the time evolution of the solution is not smooth. By doing this, an attempt is made at locally satisfying monotonicity conditions, while maintaining a high order of accuracy in most of the solution domain. When a linear high order time integration scheme is used along with a high order spatial discretization, enforcement of monotonicity imposes severe time-step restrictions. We propose to apply limiters to these time-integration schemes, thus making them non-linear. When these new schemes are used with high order spatial discretizations, solutions remain non-oscillatory for much larger time-steps as compared to linear time integration schemes. Numerical results obtained on scalar conservation equations and systems of conservation equations are highly promising.     

On the Optimality of Randomized Deadlock Avoidance Policies

This paper revisits the problem of selecting an optimal deadlock resolution strategy, when the selection criterion is the maximization of the system throughput, and the system is Markovian in terms of its timing and routing characteristics. This problem was recently addressed in some of our previous work, that (i) provided an analytical formulation for it, (ii) introduced the notion of randomized deadlock avoidance as a generalization of the more traditional approaches of deadlock prevention/avoidance, and detection and recovery, and (iii) provided a methodology for selecting the optimal randomized deadlock avoidance policy for a given resource allocation system (RAS) configuration. An issue that remained open in the problem treatment of that past work, was whether the proposed policy randomization is essential, i.e., whether there exist any RAS configurations for which a randomized deadlock avoidance policy is superior to any other policy that does not employ randomization. The work presented in this paper establishes that for the basic problem formulation where the only concern is the (unconstrained) maximization of the system throughput—or the other typical performance objectives of minimizing the system work-in-process and mean sojourn time—randomization of the deadlock resolution strategy is not essential. However, it is also shown that, sometimes, it can offer an effective mechanism for accommodating additional operational constraints, like the requirement for production according to a specified product mix. Furthermore, the undertaken analysis provides an analytical characterization of the dependence of the aforementioned performance measures on the transition rates relating to the various events of the underlying state space, which can be useful for the broader problem of synthesizing efficient scheduling policies for the considered class of resource allocation systems.     

屏幕分辨率的检测和动态调整

软件的通用性是软件成熟与否的主要标志 ,在软件的界面中自动改变屏幕分辨率是其中之一 ,从不同的方面研究了 VB中屏幕分辨率的检测手段 ,得出了动态改变屏幕分辨率的方法 ,如果加上一些画面组态的思想 ,就容易设计出通用性很好的软件     

梯度投影法应用于冗余机器人分解运动速度控制的新新方案

本文讨论分解运动速度控制框架下将梯度投影法应用于冗余机器人控制的有关问题。     

Violet

Violet is an easy-to-use theorem prover based on locking resolution, with integrated equality extensions that use term rewriting and Knuth–Bendix completion. Violet participated in the CADE-13 ATP System Competition.     

快速计算抛物线的一种新算法

分析了孙家广先生于１９８６年提出的计算抛物线的方法，提出了一种新的快速计算方法，使常数计算量减少了６６％，循环体计算量减少２Ｎ（Ｎ是一条抛物线的采样点数）．如果Ｎ很大（一般采样上百个点或几百个点），调用次数多，则减少很多计算量．新的计算方法简单，软件实现容易，实用价值较大．     

删除策略的相容性

本文给出关于删除策略相容性的几个结果，对相同谓词符号配用锁的子句集，锁归结和删除策略联用完备，对正文字锁大于负文字锁的Ｈｏｒｎ集，正单元锁归和删降策略联用完备，输入锁结与删除策略联用完备，配锁Ｈｏｒｎ集上输入半锁归结和删除联用完备的，标准Ｈｏｒｎ集上正单元强有序归结和删除策略联用完备，强有序输入归结和删除策略联用完备。