Scheduling Messages with Earliest Deadline Techniques

Thispaper discusses the applicability of earliest deadline schedulingtechniques to local area networks. The focus is on controllerarea networks (the only standard that allows direct implementation)although a comparison is tried with other possible implementationson different network topologies (and contention resolution methods).Message scheduling follows the well-known EDF algorithm. Thepaper discusses the limitations and the problems in the implementationof the algorithm on standard controller area network protocols.Then, it presents a short study on the comparative effectivenessof other contention resolution methods modeled on the standardsToken-ring and Carrier Sense Multiple Access-Collision DetectionCSMA-CD (all implementing the earliest deadline scheduling policy.)Finally, the paper shows how to compute an optimal packet sizewith respect to the guaranteeability of the real-time properties,exploiting the trade-off between preemptability and efficiency.     

高速信元优先级交换调度策略定性研究

该文根据流平衡定律和排队理论用近似求解的方法对带优先级的信元调度策略进行了定性分析研究,推导得出了更加符合实际的解析式,并通过仿真和数值计算进行了验证。     

缓冲交叉开关交换结构多播调度算法研究

高性能核心交换设备多播调度受到越来越多的关注.交叉开关结构下的多播调度方案或者性能较差,或者过于复杂,难于应用在高速交换场合.为此,提出一种面向多播的多输入队列缓冲交叉开关体系结构.将多播调度分解为信元分派、输入调度、输出调度3个可分布式并行执行的子问题,并设计了相应的调度算法,降低了算法复杂性.实验结果表明,交叉点缓冲区容量与输入队列数量对多播性能都具有很大的影响.在突发流量到达下,与单多播输入队列的体系结构相比,无论是采用O(1)复杂度的HA-RR-RR还是复杂度更高的调度算法,均能显著提高系统吞吐性能.     

基于物联网视觉的大型拥堵车辆调度系统设计

针对道路拥堵车辆调度问题,设计了一种基于物联网视觉的大型拥堵车辆调度系统,分析了系统的总体结构,给出了系统的ZigBee协调器模块、车载传感器节点、图像采集处理模块以及无线传输模块的硬件结构,详细介绍了拥堵车辆调度算法流程,并给出了车辆调度最佳路径算法代码,实现了大型拥堵车辆的有效调度;实验结果说明,所设计系统可获取有效的交通车辆拥堵图像,实现交通拥堵的高效调度.     

A Probabilistic Scheduler for the Analysis of Cryptographic Protocols

When modelling cryto-protocols by means of process calculi which express both nondeterministic and probabilistic behavior, it is customary to view the scheduler as an intruder. It has been established that the traditional scheduler needs to be carefully calibrated in order to more accurately reflect the intruder's capabilities for controlling communication channels. We propose such a class of schedulers through a semantic variant called PPC_νσ, of the Probabilistic Poly-time Calculus (PPC) of Mitchell et al. [J.C. Mitchell, A. Ramanathan, A. Scedrov, and V. Teague. A probabilistic polynomial-time process calculus for the analysis of cryptographic protocols. Theoretical Computer Science, 353:118–164, 2006] and we illustrate the pertinence of our approach by an extensive study of the Dining Cryptographers (DCP) [David Chaum. The dining cryptographers problem: Unconditional sender and recipient untraceability. J. Cryptology, 1(1):65–75, 1988] protocol. Along these lines, we define a new characterization of Mitchell et al.'s observational equivalence [J.C. Mitchell, A. Ramanathan, A. Scedrov, and V. Teague. A probabilistic polynomial-time process calculus for the analysis of cryptographic protocols. Theoretical Computer Science, 353:118–164, 2006] more suited for taking into account any observable trace instead of just a single action as required in the analysis of the DCP.     

一种优化指针策略的输入排队调度算法

针对FIRM（fcfs in round-robin matching）算法在处理非均匀业务时,延时和丢包性能出现缺陷的问题,在FIRM算法的基础上设计并实现了一种优化指针策略的low—FIRM（longest oldest weighted FIRM）算法。该算法根据队列长度和队首信元等待时间的权值修改输入端口的轮询指针。使得权值大的队列趋于优先服务,从而优化了在非均匀业务下的调度性能。接着给出了low—FIRM算法的性能分析和仿真,与iSLIP（iterative round—robin matching with slip）算法、FIRM算法进行了比较。仿真结果表明,low—FIRM与经典算法相比,在均匀业务下的性能近似,而在非均匀业务下性能有了较大的提升。     

CICQ交换机中一类服务可保障的调度策略研究

具备QoS保障能力的快速调度算法是高速交换机的首选.基于EPFTS(Ethernet-oriented physical frame timeslot switching)和CICQ(combined input-crosspoint-queued)交换技术的特点,提出了一类新的调度策略——TRWFS(timeslot reservation weighted fair scheduling).为确保各端口对上保障业务的预留带宽,TRWFS以各端口对上保障业务预留时槽数为调度权重,以优先调度保障业务和平衡各保障业务的盈余时槽(surplus timeslot,定义为现实系统和理想系统之间的服务差额)为业务调度准则.基于该调度策略进一步提出了两种实现算法——TRWFS_Ⅰ和TRWFS_Ⅱ,总体上使实现TRWFS的时间复杂度降至O(1).性能分析和仿真实验结果均表明两种调度算法都达到了服务保障的设计目标,仿真实验结果还表明CICQ排队方式下与其他调度算法相比,TRWFS和轮询调度综合的调度机制具有交叉缓存容量要求更低的优点.     

Mode Change Protocols for Real-Time Systems: A Survey and a New Proposal

This paper contains both a survey of mode change protocols for single-processor, fixed-priority, preemptively scheduled real-time systems, and a proposal of several new protocols along with their corresponding schedulability analysis and configuration methods. First, a classification of the protocols found in the literature is given and a set of requirements is proposed for their evaluation. Then, the new protocols are introduced and discussed in the light of the stated requirements. A number of mode change protocols are based on delaying the initiation of the new mode by applying an offset to the initial release of tasks in the destination mode. We tackle the problem of how to obtain these offsets for the proposed protocols. The issue of consistently sharing resources during the mode change by means of a priority inheritance protocol is also dealt with.     

Scheduling and Transport for File Transfers on High-Speed Optical Circuits

Scheduling resources on Grids is a well-known problem. The extension of Grids to LambdaGrids requires the scheduling of lambdas, i.e., end-to-end high-speed circuits. In this paper, we propose a scheduling heuristic for such lambdas in support of large-scale scientific applications that require high-throughput transfers of large files. We refer to this heuristic as Varying-Bandwidth List Scheduling (VBLS) because the scheduler returns a Time-Range-Capacity (TRC) allocation vector with varying bandwidth levels assigned for different time ranges within the duration of a transfer. The advantage of VBLS over a fixed-bandwidth allocation scheme is that it allows the scheduler to backfill any holes left in resource allocations. Enabling VBLS requires end host applications to specify the file size in their transfer requests. To characterize VBLS, we ran simulation experiments that show that VBLS performance approaches packet-switching performance. This result means that file transfers can take advantage of bandwidth that becomes available subsequent to the start of transfers, a current and critical drawback of typical fixed-bandwidth allocation schemes in circuit-switched networks. Next, we identify the key features needed in a transport protocol that works in conjunction with VBLS and develop the Varying Bandwidth Transport Protocol (VBTP). VBTP is a rate based flow control scheme that is coupled with Selective-ARQ based error control. Finally, the paper concludes with a discussion on the impact of transport problems on VBLS scheduling.     

测度型脉冲时滞大系统的指数稳定性

本文借助加权范数型向量李雅普诺夫函数和积分型时滞比较原理，首次研究了测度型脉冲时滞线性时变大系统的指数稳定性。     

Scheduling Functions for Spatiotemporal Mapping of d-Dimensional Algorithms with Homogeneous Dependences on (d-2)-Dimensional Parallel Architectures

A formalized method is proposed for construction of scheduling functions for spatiotemporal mapping of d-dimensional algorithms represented by systems of homogeneous recurrence equations on (d-2)-dimensional parallel architectures. Basic operations of the algorithms are scheduled separately by means of functions with rational coefficients.     

On-line Scheduling for Jobs with Arbitrary Release Times

This paper considers the problem of on-line scheduling a list of independent jobs in which each job has an arbitrary release time on m parallel identical machines. A tight bound is given for List Scheduling(LS) algorithm and a better algorithm is given for m2.AMS Subject Classifications: 90B35 (90C27).This research is supported by Singapore-MIT Alliance.     

Sensitivity Analysis for Scheduling Problems

This paper represents a first attempt at a systematic study of sensitivity analysis for scheduling problems. Because schedules contain both combinatorial and temporal structures, scheduling problems present unique issues for sensitivity analysis. Some of the issues that we discuss have not been considered before. Others, while studied before, have not been explored in the context of scheduling. The applicability of these issues is illustrated using well-known scheduling models. We provide fast methods to determine when a previously optimal schedule remains optimal. Other methods restore an optimal schedule after a parameter change. The value of studying the sensitivity of an optimal sequence instead of the sensitivity of an optimal schedule is demonstrated. We show that, for some problems, sensitivity analysis results depend on the positions of jobs with changed parameters. We identify scheduling problems where performing additional or different computations during optimization facilitates sensitivity analysis. To improve the robustness of an optimal schedule, selection among multiple optimal schedules is considered. We discuss which types of sensitivity analysis questions are intractable because the scheduling problem itself is intractable. We also study how heuristic error bounds vary when the data of a scheduling problem is continuously modified. Although we focus on scheduling problems, several of the issues we discuss and our classification scheme can be extended to other optimization problems.     

基于PSO算法的WNN大包线增益调参控制律设计

提出了一种基于粒子群优化算法的小波神经网络大包线调参控制律设计方法.该方法用小波函数代替了Sigmoid函数作为激活函数.由于结合了小波变换良好的高频域时间精度、低频域频率精度的性质和神经网络的自学习功能,因而具有较强逼近非线性函数的能力.为了克服局部极小值问题并进一步提高对非线性函数逼近能力,利用粒子群优化算法对小波神经网络进行参数训练,并利用该网络实现了大包线增益调参.飞行仿真结果表明,所设计的小波神经网络增益调参控制器具有优良的控制性能,不仅能够保证平衡状态下的控制效果,而且在未训练的平衡状态下依然具有良好的控制性能,并且在存在20%的建模误差时,最大超调量仅为6 m,仅是使用常规增益调参方法的18%.     

Scheduling with conflicts: online and offline algorithms

We consider the following problem of scheduling with conflicts (swc): Find a minimum makespan schedule on identical machines where conflicting jobs cannot be scheduled concurrently. We study the problem when conflicts between jobs are modeled by general graphs. Our first main positive result is an exact algorithm for two machines and job sizes in {1,2}. For jobs sizes in {1,2,3}, we can obtain a -approximation, which improves on the -approximation that was previously known for this case. Our main negative result is that for jobs sizes in {1,2,3,4}, the problem is APX-hard. Our second contribution is the initiation of the study of an online model for swc, where we present the first results in this model. Specifically, we prove a lower bound of on the competitive ratio of any deterministic online algorithm for m machines and unit jobs, and an upper bound of 2 when the algorithm is not restricted computationally. For three machines we can show that an efficient greedy algorithm achieves this bound. For two machines we present a more complex algorithm that achieves a competitive ratio of when the number of jobs is known in advance to the algorithm.     

具有约束条件的单机JIT调度问题

具有约束条件的单机ＪＩＴ调度问题齐向彤陈秋双涂生（南开大学计算机与系统科学系天津３０００７１）关键词Ｅ／Ｔ调度,优化,分支定界法．１）国家“八六三”ＣＩＭＳ主题和国家自然科学基金资助课题．收稿日期１９９５－０９－１８１引言近年来,随着Ｊｕｓｔ－ｉｎ...     

基于瓶颈感知的多级反馈队列Coflow调度机制

Coflow作为并行计算框架的典型流量模型,降低Coflow的完成时间（CCT）成为云计算领域的研究热点。现有Coflow调度机制未考虑云数据中心内网络瓶颈问题,容易造成网络拥塞,导致CCT增加。针对该问题,构建基于瓶颈感知的Coflow调度机制Bamq。利用Lagrange对偶优化Coflow调度模型,以加快Coflow流速并增大吞吐量,从而降低CCT。通过设计多级反馈队列机制,降低吞吐量对网络拥塞产生的影响,根据已发流的大小、宽度和流速信息,构建瓶颈因子以动态调整多级队列的优先级,实现拥塞感知,提高Coflow调度性能。在Facebook真实数据集上进行实验,结果表明,相比Baraat、Varys、Aalo机制,该机制的CCT平均缩短21.3%,吞吐量平均提高17.9%,能够有效提高链路的利用率。     

Scheduling the truckload operations in automated warehouses with alternative aisles for pallets

In this study, the scheduling of truck load operations in automated storage and retrieval systems is investigated. The problem is an extension of previous ones such that a pallet can be retrieved from a set of alternative aisles. It is modelled as a flexible job shop scheduling problem where the loads are considered as jobs, the pallets of a load are regarded as the operations, and the forklifts used to remove the retrieving items to the trucks are seen as machines. Minimization of maximum loading time is used as the objective to minimize the throughput time of orders and maximize the efficiency of the warehouse. A priority based genetic algorithm is presented to sequence the retrieving pallets. Permutation coding is used for encoding and a constructive algorithm generating active schedules for flexible job shop scheduling problem is applied for decoding. The proposed methodology is applied to a real problem arising in a warehouse installed by a leading supplier of automated materials handling and storage systems.     

大型企业私有云应用资源自动调度技术研究及应用

本文研究分析了大型企业私有云应用资源管理特点,参考国际领先的自动化流程编排软件的架构和功能,设计并开发云计算管理平台的应用资源自动调度技术。通过应用系统模板定制、应用运行指标监控和关联分析、IP地址和负载均衡资源自动配置等关键技术,降低了大型企业建设生产级私有云的成本。