Flexible coordinator design for modeling resource sharing in multi-agent systems

One approach to modeling multi-agent systems (MASs) is to employ a method that defines components which describe the local behavior of individual agents, as well as a special component, called a coordinator. The coordinator component coordinates the resource sharing behavior among the agents. The agent models define a set of local plans, and the combination of local plans and a coordinator defines a system’s global plan. Although earlier work has provided the base functionality needed to synthesize inter-agent resource sharing behavior for a global, conflict-free MAS environment, the lack of coordination flexibility limits the modeling capability at both the local plan level and the global plan level. In this paper, we describe a flexible design method that supports a range of coordinator components. The method defines four levels of coordination and an associated four-step coordinator generation process, which allows for the design of coordinators with increasing capabilities for handling complexity associated with resource coordination. Colored Petri net based simulation is used to analyze various properties that derive from different coordinators and synthesis of a reduced coordinator component is discussed for cases that involve homogeneous agents.     

Rendezvousing with location-aware devices: Enhancing social coordination

Emerging technologies such as location-awareness devices have the potential to significantly impact users' social coordination, particularly while rendezvousing. It is important that we explore how new technologies influence social behaviours and communication in order to realize their full potential. This paper presents a field study investigating the use of mobile location-aware devices for rendezvous activities. Participants took part in one of three mobile device conditions (a mobile phone, a location-aware handheld, or both a mobile phone and a location-aware handheld) and completed three rendezvousing scenarios. The results reveal key differences in communication patterns between the mediums, as well as the potential strengths and limitations of location-aware devices for social coordination. The paper concludes with a discussion of relevant design issues drawn from observations gathered during the field study.     

Developing a taxonomy of coordination behaviours in nuclear power plant control rooms during emergencies

Abstract

This study aims to develop a taxonomy of coordination behaviours during emergencies in nuclear power plants (NPPs). We summarised basic coordination behaviours from literature in aviation, health care and nuclear field and identified coordination behaviours specific to the nuclear domain by interviewing and surveying control crew operators. The established taxonomy includes 7 workflow stages and 24 basic coordination behaviours. To evaluate the reliability and feasibility of the taxonomy, we analysed 12 videos of operators’ training sessions by coding coordination behaviours with the taxonomy and the inter-rater reliability was acceptable. Further analysis of the frequency, the duration and the direction of the coordination behaviours revealed four coordination problems. This taxonomy provides a foundation of systematic observation of coordination behaviours among NPP crews, advances researchers’ understanding of the coordination mechanism during emergencies in NPPs and facilitate the possibility to deepen the understanding of the relationships between coordination behaviours and team performance.

Practitioner Summary: A taxonomy of coordination behaviours during emergencies in nuclear power plants was developed. Reliability and feasibility of the taxonomy was verified through the analysis of 12 training sessions. The taxonomy can serve as an observation system for analysis of coordination behaviours and help to identify coordination problems of control crews.     

Understanding the functions of teleconferences for coordinating global software development projects

One of the dominant characteristics of contemporary software development is the global distribution of tasks, of developers, of information and of technologies. Undoubtedly, such distribution engenders new coordination challenges in the form of distance‐related interdependencies. One of the predominant processes of addressing these challenges is electronic meetings (or teleconferences). However, the functions of these meetings for coordination purposes are not yet understood. The distinctive conventions of teleconferences and their causal relationships that lead to optimal coordination of global software development (GSD) projects are also not yet understood. In this paper, the functions of teleconferences held by globally distributed software developers to coordinate their work in the face of global distribution of resources, cross‐site information interdependencies and continuously changing software requirements are analysed. The analysis is based on a qualitative study of how a subunit of 13 software developers, distributed across three sites in the USA and one in Republic of Ireland, used teleconferences to address its coordination challenges. The paper proffers a teleconference approach to GSD coordination by arguing that the functions of teleconferences manifest in software developers' multitasking; their ready access to all their information as additional benefits; flexibility in their communicative behaviours; and a reduction in their structure overload. This approach draws attention to these manifestations as distinctive conventions of the de‐structured meeting, which de‐structuring is occasioned by organic information processing needs in teleconferencing. This approach also explains why the combination of global distribution and teleconferences is a strategic opportunity for information processing for software process coordination.     

一种基于策略驱动的联动平台设计与应用

提出了一种基于事件触发策略驱动的联动平台设计，描述了事件触发的策略驱动模型和平台总体结构以及平台联动过程。按照规则对安全事件队列进行处理，提高了策略的效率。使用XML语言描述策略，具有简单、高效的优点。采用组件化的思想，可将各种安全功能以组件的方式挂接在联动平台下，实现了集中控制、分散响应的管理模式，具有很好的灵活性和可扩展性。实践证明，此联动平台提高了网络安全管理的效率，对大规模网络安全管理具有很大的实用价值。     

Enhancing development team flexibility in IS projects

Information system development projects face tremendous challenges because of business changes and technology changes. Research has shown that software team flexibility has a positive effect on project outcomes, but specific requirements for enhancing flexibility are lacking. Drawing from the input-mediator-outcome (IMO) team effectiveness framework, this research investigates the contextual inputs and team processes that lead to development team flexibility and how well team flexibility improves project outcomes. A survey was developed to consider a model derived from the IMO framework. One hundred fourteen members of information systems development project teams in China responded to the survey. Partial least squares analysis was used served to analyze the data. Results indicate that a participatory culture and cooperative norms are an effective foundation for improving required processes that include project coordination of the project and knowledge sharing activities. In turn, the improved process performance extends responses to changes in technology and the business climate. The improved flexibility in meeting change is predictive of outcomes related to project performance and quality of the final product.     

Modeling the Exogenous Coordination of Mobile Channel-based Systems with Petri Nets

In this paper, we discuss how to model systems that communicate through and are coordinated by mobile channels. Mainly, we focus on modeling the exogenous coordination behavior imposed by these channels. We use Petri Nets as our modeling language, for they provide a graphically and mathematically founded modeling formalism. We give Petri Nets for a set of mobile channel types. This allows us to construct models of applications, by taking the Petri Net of each component and each mobile channel, and composing them together. For this purpose, we define a special Petri Net composition function. We also discuss analysis and simulation of these models and their exogenous coordination behavior.     

无线传感网数据不确定性及其分层多Agent调和策略

针对无线传感网数据不确定性处理有效性策略研究,分析了传感数据不确定的多样性和层次性,设计了sensor Agent、cluster and analyzer Agent和sink and decision-maker Agent三类Agent,探讨了传感数据不确定性类与多智能Agent分层对应关系。具体定义了Agent的局部不确定数据处理和通信两种调和组成模块,以及无线传感网与粗糙集技术的智能特性组合,进而提出了传感不确定性分层多智能Agent调和模型。最后,给出了相应实现算法及实例分析,结果表明该智能模型分层调和机制具有化解各类复杂传感数据不确定性的灵活性与实用性。     

Modelling temporal behaviour in complex systems with Timebands

Complex real-time systems exhibit dynamic behaviours on many different time levels. To cope with the wide range of time scales and produce more dependable computer-based systems, we develop a Timebands model that can explicitly recognise a finite set of distinct time bands in which temporal properties and associated behaviours are described. In order to formalise the Timebands model, we propose a new timed model, named Timed Circus, of Circus, which is the combination of Z, CSP, and the refinement calculus in the setting of Unifying Theories of Programming. Different from most approaches such as Timed CSP, Timed Circus uses a complete lattice in the implication ordering to model the distinctive features of the Timebands model. As a result, the semantics of the Timebands model is built upon Timed Circus to guarantee soundness of each operator and maintain consistency and coordination between different time bands. By means of two small systems, we demonstrate how the Timebands model contributes to describing complex real-time systems with multiple time scales.     

Roboskeleton: An architecture for coordinating robot soccer agents

SkeletonAgent is an agent framework whose main feature is to integrate different artificial intelligent skills, like planning or learning, to obtain new behaviours in a multi-agent environment. This framework has been previously instantiated in a deliberative domain (electronic tourism), where planning was used to integrate Web information in a tourist plan. RoboSkeleton results from the instantiation of the same framework, SkeletonAgent, in a very different domain, the robot soccer. This paper shows how this architecture is used to obtain collaborative behaviours in a reactive domain. The paper describes how the different modules of the architecture for the robot soccer agents are designed, directly showing the flexibility of our framework.     

TÆMS agents: enabling dynamic distributed supply chain management

Some dynamic supply chain problems are instances of a class of distributed optimization problems that TÆMS and other intelligent agents were made to address. In this paper we define a discrete distributed dynamic supply chain management problem and specify how TÆMS agents, equipped with new coordination mechanisms, automate and manage the supply chain. The agents increase the level of flexibility in the chain and enable members of the supply chain to be more responsive through producer/consumer negotiation and reasoning about manufacturing availability, raw material requirements, and shipping time requirements. Planning/scheduling and coordination research enables the agents to perform this level of automation on-line, responding to change as it happens in the environment, rather than relying on precomputed solutions or reasoning via abstract flow characterizations.     

On the automated translational execution of the action language for foundational UML

To manage the rapidly growing complexity of software development, abstraction and automation have been recognised as powerful means. Among the techniques pushing for them, model-driven engineering has gained increasing attention from industry for, among others, the possibility to automatically generate code from models. To generate fully executable code, models should describe complex behaviours. While pragmatically this is achieved by employing programming languages for defining actions within models, the abstraction gap between modelling and programming languages can undermine consistency between models and code as well as analysability and reusability of models. In light of this, model-aware action languages should be preferred. This is the case of the Action Language for Foundational UML (ALF). In this paper, we provide a solution for the fully automated translational execution of ALF towards C++. Additionally, we give an insight on how to simplify the transition from the use of programming languages for modelling fine-grained behaviours to model-aware action languages in industrial MDE. The solution presented in this paper has been assessed on industrial applications to verify its applicability to complex systems as well as its scalability.     

An efficient game for vehicle-to-grid coordination problems in smart grids

Emerging plug-in electric vehicles (PEVs), as distributed energy sources, are promising to provide vehicle-to-grid (V2G) services for power grids, like frequency and voltage regulations, by coordinating their active and reactive power rates. However, due to the autonomy of PEVs, it is challenging how to efficiently schedule the coordination behaviours among these units in a distributed way. In this paper, we formulate the underlying coordination problems as a novel class of Vickrey–Clarke–Groves style (VCG-style) auction games where players, power grids and PEVs do not report a full cost or valuation function but only a multidimensional bid signal: the maximum active and reactive power quantities that a power grid wants and the maximum per unit prices it is willing to pay, and the maximum active and reactive power quantities that a PEV can provide and the minimum per unit prices it asks for. We show the existence of the efficient Nash equilibrium (NE) for the underlying auction games, though there may exist other inefficient NEs. In order to deal with large-scale PEVs, we design games with aggregator players each of which submits bid profiles representing the overall utility for a collection of PEVs, and extend the so-called quantised-progressive second price mechanism to the underlying auction games to implement the efficient NE.     

An architecture for tuple‐based coordination of multi‐agent systems

Multi‐agent system development calls for powerful and expressive coordination models and languages, as well as for an effective coordination technology. A good deal of the current research effort focuses on tuple‐based coordination, exploiting its well‐known advantages, such as agent uncoupling and associative access to information, and addressing its limitations in terms of flexibility and control capabilities. In particular, the behaviour of a Linda‐like tuple space is fixed once and for all by the coordination model, and cannot be tailored to the specific application needs. Tuple centres are tuple spaces whose behaviour can be programmed by defining transactional reactions to the basic communication events, allowing coordination laws to be explicitly defined and embedded into the coordination medium. This paper presents the architecture of a run‐time system for tuple‐based coordination, where tuple centres work as an extensible kernel, around which multi‐agent systems can be designed and deployed. After sketching the implementation, the paper shows the advantages that can be achieved from both the design and the performance viewpoints. Copyright © 1999 John Wiley & Sons, Ltd.     

Efficient evaluation functions for evolving coordination

Abstract This paper presents fitness evaluation functions that efficiently evolve coordination in large multi-component systems. In particular, we focus on evolving distributed control policies that are applicable to dynamic and stochastic environments. While it is appealing to evolve such policies directly for an entire system, the search space is prohibitively large in most cases to allow such an approach to provide satisfactory results. Instead, we present an approach based on evolving system components individually where each component aims to maximize its own fitness function. Though this approach sidesteps the exploding state space concern, it introduces two new issues: (1) how to create component evaluation functions that are aligned with the global evaluation function; and (2) how to create component evaluation functions that are sensitive to the fitness changes of that component, while remaining relatively insensitive to the fitness changes of other components in the system. If the first issue is not addressed, the resulting system becomes uncoordinated; if the second issue is not addressed, the evolutionary process becomes either slow to converge or worse, incapable of converging to good solutions. This paper shows how to construct evaluation functions that promote coordination by satisfying these two properties. We apply these evaluation functions to the distributed control problem of coordinating multiple rovers to maximize aggregate information collected. We focus on environments that are highly dynamic (changing points of interest), noisy (sensor and actuator faults), and communication limited (both for observation of other rovers and points of interest) forcing the rovers to evolve generalized solutions. On this difficult coordination problem, the control policy evolved using aligned and component-sensitive evaluation functions outperforms global evaluation functions by up to 400%. More notably, the performance improvements increase when the problems become more difficult (larger, noisier, less communication). In addition we provide an analysis of the results by quantifying the two characteristics (alignment and sensitivity discussed above) leading to a systematic study of the presented fitness functions.     

Lark: Coordinating Co-located Collaboration with Information Visualization

Large multi-touch displays are expanding the possibilities of multiple-coordinated views by allowing multiple people to interact with data in concert or independently. We present Lark, a system that facilitates the coordination of interactions with information visualizations on shared digital workspaces. We focus on supporting this coordination according to four main criteria: scoped interaction, temporal flexibility, spatial flexibility, and changing collaboration styles. These are achieved by integrating a representation of the information visualization pipeline into the shared workspace, thus explicitly indicating coordination points on data, representation, presentation, and view levels. This integrated meta-visualization supports both the awareness of how views are linked and the freedom to work in concert or independently. Lark incorporates these four main criteria into a coherent visualization collaboration interaction environment by providing direct visual and algorithmic support for the coordination of data analysis actions over shared large displays.     

A behaviour-based architecture with attention control

In this paper we present a behaviour-based mobile robot system for task execution. The behaviour model of this system consists of a number of motion behaviours, including reflexes and voluntary motion behaviours, and knowledge acquisition modules providing supporting information. Execution of a task is regarded as a problem-solving process. A blackboard model is introduced to overcome some shortcomings of the behaviour-based architectures, especially concerning modularity and task execution capability. The concept of attention is introduced in the behaviour control, which is more advantageous than the behaviour control mechanisms presented in the literature. Its introduction results in situation-dependent behaviour coordination. For efficient task execution, environment knowledge is maintained in a memory. Task-achieving behaviour is designed to make use of the memory when available.     

群体行为建模语言解释器与应用描述方法研究

群体兵力行为建模语言是计算机生成兵力(CGF)系统的重要组成部分,也是国际上CGF技术领域的研究热点和难点.文章介绍了一种新的基于描述性任务逻辑的群体行为建模语言(CBML),给出了CBML语言的解释器和验证器的实现方法,研究提出了利用CBML语言描述大规模分布式虚拟战场环境中群体兵力实体的组织关系、任务规划和协同行为的描述方法和规范.试用结果表明CBML语言简洁、灵活,对群体兵力实体的组织与协同行为模型的描述能力强,应用该文提出的描述方法和规范,可高效地完成复杂群体组织与协同行为过程描述.