Coordination mechanisms: Towards a conceptual foundation of CSCW systems design

The paper outlines an approach to CSCW systems design based on the concept of coordination mechanisms. The concept of coordination mechanisms has been developed as a generalization of phenomena described in empirical investigations of the use of artifacts for the purpose of coordinating cooperative activities in different work domains. On the basis of the evidence of this corpus of empirical studies, the paper outlines a theory of the use of artifacts for coordination purposes in cooperative work settings, derives a set of general requirements for computational coordination mechanisms, and sketches the architecture of Ariadne, a CSCW infrastructure for constructing and running such malleable and linkable computational coordination mechanisms.The first version of this paper was written while Carla Simone was with the University of Milano.     

基于博弈论的多智能体协同控制算法

为实现交通的畅通,将博弈论引入到交通控制系统中。由于当前路口交通状况只受到来自邻居路口的车辆的影响,提出了基于多智能体的分布式协同控制框架,路口智能体与邻居通过协同博弈选出最优策略进行交通控制。描述了基于博弈论的协同控制算法,并通过仿真验证了该算法能够有效的适应交通流,实现交通控制。     

Wasp-like Agents for Distributed Factory Coordination

Agent-based approaches to manufacturing scheduling and control have gained increasing attention in recent years. Such approaches are attractive because they offer increased robustness against the unpredictability of factory operations. But the specification of local coordination policies that give rise to efficient global performance and effectively adapt to changing circumstances remains an interesting challenge. In this paper, we present a new approach to this coordination problem, drawing on various aspects of a computational model of how wasp colonies coordinate individual activities and allocate tasks to meet the collective needs of the nest.We focus specifically on the problem of configuring parallel multi-purpose machines in a factory to best satisfy product demands over time. Wasp-like computational agents that we call routing wasps act as overall machine proxies. These agents use a model of wasp task allocation behavior, coupled with a model of wasp dominance hierarchy formation, to determine which new jobs should be accepted into the machine's queue. If you view our system from a market-oriented perspective, the policies that the routing wasps independently adapt for their respective machines can be likened to policies for deciding when to bid and when not to bid for arriving jobs.We benchmark the performance of our system on the real-world problem of assigning trucks to paint booths in a simulated vehicle paintshop. The objective of this problem is to minimize the number of paint color changes accrued by the system, assuming no a priori knowledge of the color sequence or color distribution of trucks arriving in the system. We demonstrate that our system outperforms the bidding mechanism originally implemented for the problem as well as another related adaptive bidding mechanism.     

基于Petri Nets的协调机制研究*

利用形式化和图形化的建模工具Petri Nets对协调问题中的依赖关系及协调机制进行研究;提出任务之间基于资源的三种基本依赖关系;并用Petri Nets对这三种依赖关系相应的协调机制进行了表述,为协调问题的可计算描述提供了一种新的思考角度。     

Coordination mechanisms

We introduce the notion of coordination mechanisms to improve the performance in systems with independent selfish and non-colluding agents. The quality of a coordination mechanism is measured by its price of anarchy—the worst-case performance of a Nash equilibrium over the (centrally controlled) social optimum. We give upper and lower bounds for the price of anarchy for selfish task allocation and congestion games.     

Strip-oriented asynchronous prefetching for parallel disk systems

Sequential prefetching schemes are widely employed in storage servers to mask disk latency and improve system throughput. However, existing schemes cannot benefit parallel disk systems as expected due to the fact that they ignore the distinct internal characteristics of the parallel disk system, in particular, data striping. Moreover, their aggressive prefetching pattern suffers from premature evictions and prolonged request latencies. In this paper, we propose a strip-oriented asynchronous prefetching (SoAP) technique, which is dedicated to the parallel disk system. It settles the above-mentioned problems by providing multiple novel features, e.g., enhanced prediction accuracy, adaptive prefetching strength, physical data layout awareness, and timely prefetching. To validate SoAP, we implement a prototype by modifying the software redundant arrays of inexpensive disks (RAID) under Linux. Experimental results demonstrate that SoAP can consistently offer improved average response time and throughput to the parallel disk system under non-random workloads compared with STEP, SP, ASP, and Linux-like SEQPs.     

面向MES的炼钢-连铸协同调度系统

针对某大型钢铁联合企业炼钢．连铸主辅设备协同调度的难题,采用基于“数据、模型、知识、人机交互”四维一体的调度方法,提出了冶金MES中炼钢．连铸协同调度系统的设计原则,系统结构和功能。研发了炼钢．连铸生产调度、钢包优化配备、行车和台车协同调度系统。实际数据模拟效果良好,验证了炼钢．连铸协同调度系统的结构和方法的可行性,并受到现场调度专家的好评。     

基于约束理论的Flow-shop分解协调算法

There are many flow shop problems of throughput (denoted by FSPT) with constraints of due date in real production planning and scheduling. In this paper, a decomposition and coordination algorithm is proposed based on the analysis of FSPT and under the support of TOC (theory of constraint). A flow shop is at first decomposed into two subsystems named PULL and PUSH by means of bottleneck. Then the subsystem is decomposed into single machine scheduling problems, so the original NP-HARD problem can be transferred into a serial of single machine optimization problems finally. This method reduces the computational complexity, and has been used in a real project successfully.     

面向分布式信息服务平台的协调中间件系统

为了更好地满足用户对分布式信息服务平台的QoS要求，对一个异构的数据库簇进行了研究，提出了基于该簇的一个协调中间件的逻辑模型，并对其设计思想及实现方法进行了详细介绍。该模型将数据的新鲜度引入设计过程，用它作为事务处理的QoS参数来提高系统服务质量。     

A Decomposition and Coordination Scheduling Method for Flow-shop Problem Based on TOC

There are many flow shop problems of throughput (denoted by FSPT) with constraints of due date in real production planning and scheduling. In this paper, a decomposition and coordination algorithm is proposed based on the analysis of FSPT and under the support of TOC (theory of constraint). A flow shop is at first decomposed into two subsystems named PULL and PUSH by means of bottleneck. Then the subsystem is decomposed into single machine scheduling problems, so the original NP-HARD problem can be transferred into a serial of single machine optimization problems finally. This method reduces the computational complexity, and has been used in a real project successfully.     

Multi‐Unit Bayesian Auction with Demand or Budget Constraints

We consider the problem of revenue maximization on multi‐unit auctions where items are distinguished by their relative values; any pair of items has the same ratio of values to all buyers. As is common in the study of revenue maximizing problems, we assume that buyers' valuations are drawn from public known distributions and they have additive valuations for multiple items. Our problem is well motivated by sponsored search auctions, which made money for Google and Yahoo! in practice. In this auction, each advertiser bids an amount b_i to compete for ad slots on a web page. The value of each ad slot corresponds to its click‐through‐rate, and each buyer has her own per‐click valuations, which is her private information. Obviously, a strategic bidder may bid an amount that is different with her true valuation to improve her utility. Our goal is to design truthful mechanisms avoiding this misreporting. We develop the optimal (with maximum revenue) truthful auction for a relaxed demand model (where each buyer i wants at most d_i items) and a sharp demand model (where buyer i wants exactly d_i items). We also find an auction that always guarantees at least half of the revenue of the optimal auction when the buyers are budget constrained. Moreover, all of the auctions we design can be computed efficiently, that is, in polynomial time.     

Simple reinforcement learning agents: Pareto beats Nash in an algorithmic game theory study

Repeated play in games by simple adaptive agents is investigated. The agents use Q-learning, a special form of reinforcement learning, to direct learning of behavioral strategies in a number of 2×2 games. The agents are able effectively to maximize the total wealth extracted. This often leads to Pareto optimal outcomes. When the rewards signals are sufficiently clear, Pareto optimal outcomes will largely be achieved. The effect can select Pareto outcomes that are not Nash equilibria and it can select Pareto optimal outcomes among Nash equilibria.Acknowledgement This material is based upon work supported by, or in part by, NSF grant number SES-9709548. We wish to thank an anonymous referee for a number of very helpful suggestions.     

一类平转耦合并联机构运动学性能的评价方法

三自由度平转耦合并联机构已在航空大型结构件加工中得到应用,但因这类机构的Jacobian矩阵量纲不统一,故难于用其代数特征评价机构的运动学性能.本文基于螺旋理论构造出3-PRS并联机构速度映射模型,采用虚功原理定义了两种可描述机构链内和链间瞬时功率传递特性的无量纲运动学性能评价指标,并通过算例说明其有效性.研究成果对指导这类并联机构的运动学优化设计具有重要的参考价值.     

群机器人多目标搜索中的合作协同和竞争协同

群机器人进行多目标搜索时,通过任务分工形成多个子群,各子群分别针对一个意向目标协同搜索,故围绕子群协同中存在的合作关系和竞争关系提出控制策略.为进行合作协同,建立子群发言人的动态遴选机制,不同子群的发言人进行通信,交换所属各子群的最优信息,引导本子群的搜索行为;为进行竞争协同,引入承包机制,按子群的优势地位高低决定是承包还是放弃对某些目标的搜索.两类协同控制的仿真结果表明,合作协同扩大了机器人的感知范围,竞争协同降低了空间冲突机率.二者综合作用,明显提高了群机器人的搜索效率.     

不同时变延迟下的多AUV编队协调控制

针对无领航者AUV编队协调控制问题,提出了一种不同时变通信延迟下的一致性协调控制方法;首先考虑到AUV之间水下通信存在时间延迟和数据丢失的问题,利用状态反馈线性化理论处理AUV数学模型中的非线性耦合项,从而将复杂的AUV模型转换为双积分器动态模型;其次,针对不同延迟通信情况,设计了位置和速度双独立的拓扑结构以减少编队成员之间发送每个数据包中的数据量;最后,提出了无领航者的多AUV稳定条件,进而将多AUV编队控制问题看作是一致性问题,基于Laypunov-Razumikhin定理证明时延多AUV编队系统的稳定性;该控制方法不仅能够克服不同时变延迟和数据丢失对编队的影响,使所有以随机位置和速度出发的AUV的三维轨迹均能达到一致状态,同时能抑制外界干扰;仿真结果与所提控制方法理论结果一致。     

Equilibrium stability in decentralized design systems

The focus of this paper is on complex systems, and it presents a theoretical study of the design of complex engineering systems. More particularly, this paper studies the stability of equilibria in decentralized design environments. Indeed, the decentralization of decisions is often recommended in the design of complex systems, and the decomposition and coordination of decisions are a great challenge. The mechanisms behind this network of decentralized design decisions create difficult management and coordination issues. However, developing efficient design processes is paramount, especially with market pressures and customer expectations. Standard techniques to modelling and solving decentralized design problems typically fail to understand the underlying dynamics of the decentralized processes and therefore result in suboptimal solutions. This paper aims to model and understand the mechanisms and dynamics behind a decentralized set of decisions within a complex design process. Complex systems that are multidisciplinary and highly nonlinear in nature are the primary focus of this paper. Therefore, techniques such as response surface approximations and Game Theory are used to discuss and solve the issues related to multidisciplinary optimization. Nonlinear control theory is used in this paper as a new approach to study the stability of equilibrium points of the design space. Illustrations of the results are provided in the form of the study of the decentralized design of a pressure vessel.     

Coordination arrival control for multi‐agent systems

The coordination arrival problems of first‐order multi‐agent systems with the arriving structure and the time structure requirements are considered for the cases with no obstacle and obstacle. To describe the distributed coordination arrival problems, we first introduce needed definitions, such as coordination arrival, threat point, and arrival structure. By selecting the estimated value of the arriving time of the agent as variable, we then develop a central estimating algorithm, which is used to construct the arriving protocols. Based on the estimating algorithm, we build and analyze coordination arriving protocols for the proposed coordination arrival problems. Several simulation examples are presented to validate the proposed algorithms. Copyright © 2015 John Wiley & Sons, Ltd.