Distributed Coordination in Heterogeneous Multi-Robot Systems

Coordination in multi-robot systems is a very active research field in Artificial Intelligence and Robotics, since through coordination one can achieve a more effective execution of the robots' tasks. In this paper we present an approach to distributed coordination of a multi-robot system that is based on dynamic role assignment. The approach relies on the broadcast communication of utility functions that define the capability for every robot to perform a task and on the execution of a coordination protocol for dynamic role assignment. The presented method is robust to communication failures and suitable for application in dynamic environments. In addition to experimental results showing the effectiveness of our approach, the method has been successfully implemented within the team of heterogeneous robots Azzurra Robot Team in a very dynamic hostile environment provided by the RoboCup robotic soccer competitions.     

可视化分布组件协调环境

分布组件的协调是基于组件的分布系统开发中的一个基本问题。针对具体应用,提出了一种分布组件协调模型－－Ｃｏｎｃｅｒｔｏ。Ｃｏｎｃｅｒｔｏ模型以Ｐｅｔｒｉ网为理论基础,综合了现有的控制驱动和数据驱动两类协调模型。Ｐｅｔｒｉ网的变迁与分布组件系统中的事件、条件、操作和时间信息结合起来,提供了与计算机系统交互的方法。在Ｃｏｎｃｅｒｔｏ模型基础上,实现了可视化分布组件协调环境,对分布组件系统进行并发死锁验证     

Specification Diagrams for Actor Systems

Specification diagrams (SD's) are a novel form of graphical notation for specifying open distributed object systems. The design goal is to define notation for specifying message-passing behavior that is expressive, intuitively understandable, and that has formal semantic underpinnings. The notation generalizes informal notations such as UML's Sequence Diagrams and broadens their applicability to later in the design cycle. Specification diagrams differ from existing actor and process algebra presentations in that they are not executable per se; instead, like logics, they are inherently more biased toward specification. In this paper we rigorously define the language syntax and semantics and give examples that show the expressiveness of the language, how properties of specifications may be asserted diagrammatically, and how it is possible to reason rigorously and modularly about specification diagrams.     

可视化语言文法形式化描述综述

可视化是人机交互的主要形式,可视化语言是计算机科学中一个重要研究领域,文法为可视化语言提供了一种有价值的形式化描述方法。本文基于可视化语言的特征,介绍了可视化语言文法形式化描述体系的基本理论,分析了几种典型形式模型,并探讨了当前的主要研究内容和面临的挑战。     

Learning Situation-Specific Coordination in Cooperative Multi-agent Systems

Achieving effective cooperation in a multi-agent system is a difficult problem for a number of reasons such as limited and possibly out-dated views of activities of other agents and uncertainty about the outcomes of interacting non-local tasks. In this paper, we present a learning system called COLLAGE, that endows the agents with the capability to learn how to choose the most appropriate coordination strategy from a set of available coordination strategies. COLLAGE relies on meta-level information about agents' problem solving situations to guide them towards a suitable choice for a coordination strategy. We present empirical results that strongly indicate the effectiveness of the learning algorithm.     

A Systematic Approach to the Petri Net Based Specification of Concurrent Systems

We describe an approach to the specification of concurrent systems which enables a Petri net model of a system to be built up in a systematic way starting from a trace-based CSP specification. This method enables the separate specification of the behavior of each component (process) and their interactions in terms of the feasible sequences of events in which they can be involved. A set of rules is then applied to transform the trace-based specifications into a complete Petri net that is analyzed and/or executed to validate system behavior. The domain transformation procedure is fully automatable. The specification of a safety-critical railway control system is used as a case study.     

园林景观与周边环境视觉协调性评估仿真研究

针对当前景观评估方法存在的评估准确性差、复杂度高的问题,提出基于模糊统计的园林景观与周边环境视觉协调性评估方法。对评估指标进行初选,其中大致包含园林景观和安全协调性、园林景观和人类视觉协调性、园林景观和生态协调性三部分。根据初选结果,确定景观与周边环境在质量方面的协调性评估指标、景观与周边环境在多样完整性方面的协调性评估指标、景观与周边环境在生态适宜性方面的协调性评估指标三个一级评估指标,并将各一级评估指标划分为若干二级指标。利用模糊统计法对各个评估指标赋予权重,设定指标权重判断的相关专家集合和专家对指标权值判定的区间,通过样本落影函数表征各个集值区间组合的集值统计序列,获取各指标权重值,对其进行归一化,并利用区间方差法对权重赋值可靠程度进行校正。根据二级评估指标赋值结果得到一级评估指标赋值结果,以此构建园林景观与周边环境视觉协调性评估模型。实验结果表明,所提方法评估准确率高、复杂度低。     

基于平滑调度的弱硬实时系统约束规范

约束规范是弱硬实时系统研究的基础。从弱硬实时系统的定义出发,提出了一个新的约束规范,它能够有效实现平滑调度。给出并证明了弱硬实时系统约束规范严格性比较的一个重要定理。业已证明,该约束规范具有良好的性能和较好的适用范围。     

Modular Control and Coordination of Discrete-Event Systems

In the supervisory control of discrete-event systems based on controllable languages, a standard way to handle state explosion in large systems is by modular supervision: either horizontal (decentralized) or vertical (hierarchical). However, unless all the relevant languages are prefix-closed, a well-known potential hazard with modularity is that of conflict. In decentralized control, modular supervisors that are individually nonblocking for the plant may nevertheless produce blocking, or even deadlock, when operating on-line concurrently. Similarly, a high-level hierarchical supervisor that predicts nonblocking at its aggregated level of abstraction may inadvertently admit blocking in a low-level implementation. In two previous papers, the authors showed that nonblocking hierarchical control can be guaranteed provided high-level aggregation is sufficiently fine; the appropriate conditions were formalized in terms of control structures and observers. In this paper we apply the same technique to decentralized control, when specifications are imposed on local models of the global process; in this way we remove the restriction in some earlier work that the plant and specification (marked) languages be prefix-closed. We then solve a more general problem of coordination: namely how to determine a high level coordinator that forestalls conflict in a decentralized architecture when it potentially arises, but is otherwise minimally intrusive on low-level control action. Coordination thus combines both vertical and horizontal modularity. The example of a simple production process is provided as a practical illustration. We conclude with an appraisal of the computational effort involved.     

切换网络拓扑下Euler-Lagrange系统的分布式协调控制

研究切换网络拓扑下含未知参数的分布式Euler-Lagrange系统(简称EL系统)的自适应协调控制问题.通过引入一种新颖的自适应控制构架,设计了分散式控制器,使其容许未知的系统参数.基于图论,Lyapunov稳定性理论以及切换控制理论证明了算法的稳定性.本文特色在于在同一理论框架下处理EL系统协调控制中的未知参数问题与切换拓扑问题,实现静态和动态两种情况下的控制目标.仿真结果验证了算法的有效性.     

软件系统协调技术研究

复杂软件系统常常由若干子系统或组件通过组装而成,子系统或组件之间的有效协调是系统开发的一个关键问题.特别是在开放、分布和移动的企业计算环境下,软件系统包含大量异构实体,对协调的可重用性、动态性和适应性提出了更高的要求,以应对业务环境和用户需求的持续变化.对软件系统协调技术的研究现状进行了综述,从协调体系结构、协调设计与实现方法学、协调活动的表示等视角对目前的协调技术进行了总结,探讨了复杂软件系统的协调策略,最后指出了目前协调技术存在的问题和面临的挑战.     

Temporal Coordination –On Time and Coordination of CollaborativeActivities at a Surgical Department

An activity is inseparably bound up with time, and interdependentcooperative activities thus need to be coordinated in time. The nature oftime is therefore an ever-present issue in the design of computer systemssupporting coordination. Based on Activity Theory this paper defines theconcept of Temporal Coordination. Then, based on in-depth studies of thesocio-temporal aspects of coordinating cooperative work at hospitals, thepaper explores this notion of temporal coordination. This analysis identifiessome of the highly intertwined temporal problems, constraints, interests,and conflicts, which arise when work subject to temporal limits is to becoordinated. The paper then introduces the PATIENT SCHEDULER, which isa prototype designed during this project to illustrate how aspects oftemporal coordination can be supported by computer technology.     

无人系统的视觉感知安全研究

随着现代科技的不断革新,以机器学习尤其是深度学习为代表的人工智能技术正在改变无人系统的发展,推动无人作战等作战形态快速演变,对未来战争带来颠覆性影响。然而由于深度学习的不可解释性、脆弱性等问题,人工智能技术在现实应用中产生了诸多不确定性和安全风险。本文聚焦人工智能技术在军事无人系统中的安全问题,从视觉感知的角度出发,重点分析了安全风险来源、对抗样本理论和视觉感知对抗攻击方法和防御对策,最后对无人系统领域人工智能应用的安全问题进行了总结。     

Towards a Framework for Visual Model Development

A number of decision support systems (DSS) based on a visual interactive simulation (VIS) model have been implemented in recent years. A key component of a VIS model is the visual model. Existing VIS model development methodologies suggest methods (such as the paper prototype method) for developing a visual model. However, these methods are quite general and do not contain a framework to guide development. This paper describes a framework which combines the paper prototype method with systems concepts to develop the visual model. The proposed framework consists of eight stages. A project proof of principle example is described in which a VIS-based DSS provides support to the owner of a company selling telephone systems.     

符合人眼视觉特性的视频质量评价模型

视频技术的发展为其质量评价的出了新的课题,但由于评价图像质量的关键在于所用视觉模型是否符合人的感知特性,因此评价图象质量必须考虑以视觉锐度,对比度敏感度,多通道结构和掩盖特性为基础的人眼视觉特性（HVS）,为了使人们对基于人眼视觉特性的视频质量评价模型研究现状有所了解,介绍了几种目前比较成功的基于HVS的视频质量评价模型,并分析和总结了它们的性能,最后展望了评价模型的发展。     

分布式多媒体系统中对象表示模型及变换方法研究

在设计一个分布式多媒体系统时，具有挑战性的问题之一是如何在系统的不同层次为各模式设计合适的规格描述模型，并提供不同模型的变换方法的集成与同步策略，在本文中，我们给出了几种多媒体对象的表示模型和变换算法，它们把高层的多媒体对象变换成可以用来支持多媒体对象展示和通信的实用模式，在该模式中能较好地保持多媒体对象的集成与同步特性。