有理数域基于膜计算的算术运算设计与实现

为了生物计算机的实现,算术运算是完成所有计算模型的最基本运算;到目前为止,对膜系统中算术运算的研究只是处于整数域内,还没有实现有理数域内的算术运算;为实现有理数域的乘除法运算,基于生物类细胞模型,介绍了膜计算的基本原理和特性,然后构造基于规则优先级的算术P系统来实现有理数域内的乘法和除法,并举出相应的例子进行详细的说明以及实验仿真;实验仿真结果表明,提出的构造分数P系统来实现有理数域内的乘除法的思想和设计的规则是正确的,能够得到预期目标。     

A semantics of introspection in a reflective prototype-based language

In Malenfant et al. [19], we have described a reflective model for a prototype-based language based on thelookup o apply reflective introspection protocol. In this paper, we augment our previous protocol by converting it to handle continuations reified as first-class objects. First-class continuations provide much more control over the current computation; during the introspection phase fired by message sending, they make it possible not only to change the behavior of the program for that message but also for the entire future computation. In this paper, we provide this introspection protocol with a formal semantics. This result is obtained by exhibiting a mapping from program configurations to priority rewrite systems (PRS) as well as a mapping from message expressions to ground first-order terms used to query the PRS. Other advantages of this approach are: to ensure the termination of the introspection using the smallest set of formally justified conditions and to provide a clear declarative account of this reflective protocol. The PRS also appears as a meta-level to the base language, independent of the implementation, but from which we derive fundamental clues to obtain an efficient language processor. By our new model, we finally highlight the link between reflection in object-oriented languages and the one originally proposed by 3-Lisp [24], although object-orientation provides reusability to reflection, making it easier to use.     

Abstract argumentation

In this paper we explore the thesis that the role of argumentation in practical reasoning in general and legal reasoning in particular is to justify the use of defeasible rules to derive a conclusion in preference to the use of other defeasible rules to derive a conflicting conclusion. The defeasibility of rules is expressed by means of non-provability claims as additional conditions of the rules.We outline an abstract approach to defeasible reasoning and argumentation which includes many existing formalisms, including default logic, extended logic programming, non-monotonic modal logic and auto-epistemic logic, as special cases. We show, in particular, that the admissibility semantics for all these formalisms has a natural argumentation-theoretic interpretation and proof procedure, which seem to correspond well with informal argumentation.In the admissibility semantics there is only one way for one argument to attack another, namely by undermining one of its non-provability claims. In this paper, we show how other kinds of attack between arguments, specifically how rebuttal and priority attacks, can be reduced to the undermining of non-provability claims.     

A dynamic priority-based approach to concurrent toolpath planning for multi-material layered manufacturing

This paper presents an approach to concurrent toolpath planning for multi-material layered manufacturing (MMLM) to improve the fabrication efficiency of relatively complex prototypes. The approach is based on decoupled motion planning for multiple moving objects, in which the toolpaths of a set of tools are independently planned and then coordinated to deposit materials concurrently. Relative tool positions are monitored and potential tool collisions detected at a predefined rate. When a potential collision between a pair of tools is detected, a dynamic priority scheme is applied to assign motion priorities of tools. The traverse speeds of tools along the x-axis are compared, and a higher priority is assigned to the tool at a higher traverse speed. A tool with a higher priority continues to deposit material along its original path, while the one with a lower priority gives way by pausing at a suitable point until the potential collision is eliminated. Moreover, the deposition speeds of tools can be adjusted to suit different material properties and fabrication requirements. The proposed approach has been incorporated in a multi-material virtual prototyping (MMVP) system. Digital fabrication of prototypes shows that it can substantially shorten the fabrication time of relatively complex multi-material objects. The approach can be adapted for process control of MMLM when appropriate hardware becomes available. It is expected to benefit various applications, such as advanced product manufacturing and biomedical fabrication.     

公交信号优先策略研究

本文介绍了公交优先策略的概念和分类,阐述了绿灯延长、绿灯提前、相位倒转、相位插入、公交通行专用相位等主动优先控制策略的基本原理,并对其进行了适应性和优缺点分析。     

基于价值密度的替代与事务优先级分派策略

针对基于替代/补偿的实时事务模型中的优先级分派问题,提出基于价值密度的替代与事务优先级分派策略PBAC。在PBAC中,替代优先级基于替代的价值密度,并与替代的执行时间和紧迫性相关,事务优先级继承自替代的优先级,并受事务执行度的影响。仿真实验结果证明,该策略使系统可以更好地对基于替代/补偿的事务模型进行调度。     

基于模糊理论的任务分配与调度算法

基于模糊可靠性分配中的综合评判方法,提出一种用于数据并行交换的任务分配与调度算法。综合考虑影响任务优先级的各个因素及各影响因素自身的模糊特性,从而确定任务优先级,并解决任务分配过程中优先级的模糊决策问题。实验结果表明,该算法能提高任务的执行成功率,缩短任务的平均等待时间。     

基于样本块的破损唐卡图像修复算法的改进

基于样本块的修复算法由于能同时有效地修复图像的受损纹理和结构的优点被引入到唐卡图像的数字化保护中,而且它对特定破损唐卡图像修复效果良好,但是由于优先权计算和最佳样本块不唯一等问题的影响,算法对其他类唐卡图像修复效果不佳。针对此算法的不足,对信任度计算方法和等照线计算方法进行了改进,解决了最佳样本块不唯一的问题。实验结果证明,改进后的算法不仅能够得到令人满意的修复结果而且能够提高修复效率。     

基于价值密度和截止期的网格作业调度算法

对商业网格中的作业调度问题进行研究,采用作业的到达时间、计算量、预算和截止期4个参数定义作业的优先级。在此基础上提出基于价值密度和相对截止期的网格作业调度算法,并对其进行仿真。仿真结果表明,该算法在实现价值率、按时完成作业数和加权作业按时完成率3个性能指标上优于现有算法,兼顾了消费者和服务者的利益。     

基于多代理和多优先队列的短信实时并发算法

针对Modem发送短信在实时性、并发性及完整性等性能上存在的缺陷,提出基于多代理、多优先级队列的短信实时并发算法。该算法采用多代理、多优先级队列、线程池等技术手段保证短信控制的实时性、并发性及数据完整性,在算法中使用优先级,使某些信息能够优先发送。通过改造排队论模型和实验对算法进行验证,并将该算法应用于SMAS系统,系统运行结果表明,该算法大幅提高了其发送和接收短信的速度与效率,实现了短信实时性和并发性的目标,优化了SMAS系统的整体性能。