动力传动协同仿真平台中的主体交互协议

本文提出了一种主体交互协议的表示法,构建一个包括知识层、会话控制层、通信层的三层主体体系结构,我们在会话控制层嵌入一个协议解释程序来处理主体间的交互,这样可以使主体灵活地选择协议,减轻推论的负担,简化知识层的结构。     

基于本体和会话策略的多主体交互协议描述方法

提出一种基于会话策略的多主体交互协议描述方法。交互协议中的消息用言语动作来表示,这些言语动作被描述为WS-Agreement的schema;会话策略则描述了消息传递的流程以及交互过程中的上下文信息,如参与者属性、时间阈值等等,所有这些会话策略组成了一个多主体交互协议;采用本体描述语言OWL作为会话策略的表示语言。这种方法使得主体在一个开放、动态的环境中可以灵活地选择交互协议。     

基于多模态知识图的用户微行为会话推荐

基于会话推荐的目标是根据给定的会话预测下一个交互项.针对现有基于会话推荐大多只关注某个用户交互项的连续项来捕获相关信息;以及利用知识图谱提供辅助信息的过程中忽略了多模态知识图中各种数据类型的问题.本文提出多模态知识图的用户微行为的会话模型,将用户微行为和多模态知识纳入基于会话推荐的多任务学习中,用户微行为对项目的建模在微观行为级别上,使用一系列项目操作对来充分捕获会话中的用户意图.提出多模态知识图注意力网络,通过使用多模态图注意机制进行信息传播,将得到的聚集嵌入表示进行推荐.考虑候选项目信息来平衡局部和全局表示的门控模块,门控模块利用多层感知器层对候选项目、最近交互项目和每个用户的全局偏好之间的关系进行建模来计算权重.在两个基准数据集的实验结果表明,本文所提模型优于最新基于会话的推荐,有利于提升推荐的准确率.     

基于SOAP协议的Agent通信语言的研究

Agent通信语言是实现多Agent系统交互与合作的基础。SOAP作为一种新的与平台无关的通信协议,可以实现异构多信息的交换,使得各孤立系统的通信变得容易。文中在分析Agent通信语言,XML,SOAP,WebService等技术的基础上,结合KQML语言提出了一种基于SOAP协议的Agent通信实现方法,这种方法的消息结构由三层组成:SOAP层、KQML层和内容层。并分析了这种三层结构的消息表示的优势及其在实际系统中的应用。     

融合交互注意力和参数自适应的商品会话推荐

在电商场景中,用户面对繁杂的商品时往往难以快速检索到所需商品,而基于会话的商品推荐能通过学习用户短期兴趣从而为其推荐可能感兴趣的商品,因此基于会话的推荐研究具有显著的理论和应用研究价值。已有的会话推荐算法大多关注于利用全局图中的信息来增强会话图中的表征学习,而忽略了会话图和全局图上物品表征之间的交互关系。该文提出一种通过交互注意力和改进参数自适应策略增强的图神经网络商品会话推荐模型。交互注意层通过提取强相关信息来修正全局图和会话图中的商品表示,而参数自适应层则通过改进参数自适应策略动态权重调整以获得物品的最终表示进而用于预测。实验结果表明,该文所提出的模型在Tmall数据集上显著优于对比模型。     

基于SOAP协议的Agent通信语言的研究

Agent通信语言是实现多Agent系统交互与合作的基础.SOAP作为一种新的与平台无关的通信协议,可以实现异构多信息的交换,使得各孤立系统的通信变得容易.文中在分析Agent通信语言,XML,SOAP,Web Service等技术的基础上,结合KQML语言提出了一种基于SOAP协议的Agent通信实现方法,这种方法的消息结构由三层组成:SOAP层、KQML层和内容层.并分析了这种三层结构的消息表示的优势及其在实际系统中的应用.     

一种具有双重QoS保证的VOD流媒体系统结构

文中提出了一种基于IP网络具有双重QoS保证的VOD流媒体系统结构.此结构使用RSVP协议对流媒体预留资源,资源预留采用基于节的资源管理方法;服务器端通过RTP协议传输实时多媒体数据流,RTCP协议监视传输服务质量进行动态QoS控制,因此对基于IP网络的VOD系统的流媒体传输QoS提供了双重保证.其客户端使用SDP协议取得流媒体文件描述信息和组播地址,通过RTSP协议与流媒体文件服务器交互,建立和控制多媒体会话.     

一种基于CPN的运行时监控服务交互行为的方法

BPEL对Web服务组合的描述特性使得它很难表达和分析服务组合中的交互行为属性.这些行为属性需要遵循一定的交互协议.然而良定义的交互协议还是容易受到侵犯,这将导致服务组合进程产生状态不一致的问题.为了解决这类实际交互行为与其服务组合描述之间的不一致性问题,提出了一种由BPEL描述自动构造运行时监控器的方法.首先提出了一种基于有色Petri网(CPN)的形式化表示模型以及服务组合规约到模型的映射方法,用于精确表达从BPEL流程描述中提取的服务交互行为规约.然后,描述了由CPN形式化表示模型生成运行时监控器的方法.该运行时监控器能够捕获所有进出服务组合进程的交互消息,并且检测是否存在违背交互协议的行为.     

基于邻域感知图神经网络的会话推荐

在基于会话的推荐中,图神经网络及其改进模型将会话内复杂的交互关系建模为图结构并从中捕获项目特征,是现有推荐模型中性能较好的一类方法。然而大多数模型都忽略了不同会话之间可能存在的有效信息,仅对当前会话建模难以利用其他会话,也无法发挥邻域信息的辅助作用。因此提出基于邻域感知图神经网络的会话推荐（NA-GNN）。该模型构建会话层和全局邻域层的图结构捕获项目表示,结合注意力机制聚合两种项目表征,将会话序列之间的互信息最大化地结合到网络训练中。在真实的数据集Yoochoose和Diginetica上进行实验,与性能最优的基准模型相比,模型P@20在Yoochoose上提高了1.85%,在Diginetica上提升了7.19%;MRR@20分别提升了0.48%和8.36%,证明模型的有效性和合理性。     

基于动态知识图谱和深度神经网络的会话推荐方法

基于深度神经网络对会话进行建模的方法在处理会话序列数据时忽视了项目动态知识和会话中的操作行为,影响了推荐的准确性问题,为此提出基于动态知识图谱和深度神经网络的会话推荐方法。分别采用图神经网络和循环神经网络学习项目序列和操作序列的特征表示,结合动态知识图谱的项目知识进行建模以达到动态推荐的目的。实验结果表明,该方法能够提高推荐结果的准确性,更为有效预测用户的下一个交互项目。     

How to Prove Impossibility Under Global Fairness: On Space Complexity of Self-Stabilizing Leader Election on a Population Protocol Model

A population protocol is one of distributed computing models for passively-mobile systems, where a number of agents change their states by pairwise interactions between two agents. In this paper, we investigate the solvability of the self-stabilizing leader election in population protocols without any kind of oracles. We identify the necessary and sufficient conditions to solve the self-stabilizing leader election in population protocols from the aspects of local memory complexity and fairness assumptions. This paper shows that under the assumption of global fairness, no protocol using only n−1 states can solve the self-stabilizing leader election in complete interaction graphs, where n is the number of agents in the system. To prove this impossibility, we introduce a novel proof technique, called closed-set argument. In addition, we propose a self-stabilizing leader election protocol using n states that works even under the unfairness assumption. This protocol requires the exact knowledge about the number of agents in the system. We also show that such knowledge is necessary to construct any self-stabilizing leader election protocol.     

Applying game theory mechanisms in open agent systems with complete information

Game theory is a popular tool for designing interaction protocols for agent systems. It is currently not clear how to extend this to open agent systems. By “open” we mean that foreign agents will be free to enter and leave different systems at will. This means that agents will need to be able to work with previously unseen protocols. There does not yet exist any agreement on a standard way in which such protocols can be specified and published. Furthermore, it is not clear how an agent could be given the ability to use an arbitrary published protocol; the agent would need to be able to work out a strategy for participation. To address this we propose a machine readable language in which a game theory mechanism can be written in the form of an agent interaction protocol. This language allows the workings of the protocol to be made public so that agents can inspect it to determine its properties and hence their best strategy. Enabling agents to automatically determine the game theoretic properties of an arbitrary interaction protocol is difficult. Rather than requiring agents to find the equilibrium of a game, we propose that a recommended equilibrium will be published along with the protocol; agents can then check the recommendation to decide if it is indeed an equilibrium. We present an algorithm for this decision problem. We also develop an equilibrium which simplifies the complexity of the checking problem, while still being robust to unilateral deviations.     

基于协议分析的网络入侵检测技术

网络协议分析是网络入侵检测中的一种关键技术,当前主要方法是对网络层和传输层协议进行分析。文章基于状态转换进行协议分析和检测,以充分利用协议的状态信息检测入侵,有效地完成包括应用层协议在内的网络各层协议的分析,更加精确地定位了检测域,提高了检测的全面性、准确性和检测效率;这种方法综合了异常检测和误用检测技术,可以更有效地检测协议执行时的异常和针对协议的攻击,并且可检测变体攻击、拒绝服务攻击等较难检测的攻击。     

三方认证协议BNV的分析及改进

多个主体之间的安全会话需要有可靠的多方认证协议来保证。基于安全协议的操作语义模型,分析了三方认证协议BNV的安全性,结果表明该协议存在一致性和同步性缺陷。为此,修改了协议的消息结构并添加了标识协议主体身份的消息项。对改进后协议的安全性进行分析,结果表明改进后的协议不存在原协议的缺陷,协议参与主体满足一致性与同步性要求。最后,基于改进后协议,提出了一个n方认证协议的协议原型。     

Automated online monitoring of distributed applications through external monitors

It is a challenge to provide detection facilities for large-scale distributed systems running legacy code on hosts that may not allow fault tolerant functions to execute on them. It is tempting to structure the detection in an observer system that is kept separate from the observed system of protocol entities, with the former only having access to the latter's external message exchanges. In this paper, we propose an autonomous self-checking monitor system, which is used to provide fast detection to underlying network protocols. The monitor architecture is application neutral and, therefore, lends itself to deployment for different protocols, with the rulebase against which the observed interactions are matched, making it specific to a protocol. To make the detection infrastructure scalable and dependable, we extend it to a hierarchical monitor structure. The Monitor structure is made dynamic and reconfigurable by designing different interactions to cope with failures, load changes, or mobility. The latency of the monitor system is evaluated under fault free conditions, while its coverage is evaluated under simulated error injections.     

Agents in Electronic Commerce: Component Technologies for Automated Negotiation and Coalition Formation

Automated negotiation and coalition formation among self-interested agents are playing an increasingly important role in electronic commerce. Such agents cannot be coordinated by externally imposing their strategies. Instead the interaction protocols have to be designed so that each agent is motivated to follow the strategy that the protocol designer wants it to follow. This paper reviews six component technologies that we have developed for making such interactions less manipulable and more efficient in terms of the computational processes and the outcomes: 1. OCSM-contracts in marginal cost based contracting, 2. leveled commitment contracts, 3. anytime coalition structure generation with worst case guarantees, 4. trading off computation cost against optimization quality within each coalition, 5. distributing search among insincere agents, and 6. unenforced contract execution. Each of these technologies represents a different way of battling self-interest and combinatorial complexity simultaneously. This is a key battle when multi-agent systems move into large-scale open settings.     

Reasoning about Commitments in the Event Calculus: An Approach for Specifying and Executing Protocols

Commitments among agents are widely recognized as an important basis for organizing interactions in multiagent systems. We develop an approach for formally representing and reasoning about commitments in the event calculus. We apply and evaluate this approach in the context of protocols, which represent the interactions allowed among communicating agents. Protocols are essential in applications such as electronic commerce where it is necessary to constrain the behaviors of autonomous agents. Traditional approaches, which model protocols merely in terms of action sequences, limit the flexibility of the agents in executing the protocols. By contrast, by formally representing commitments, we can specify the content of the protocols through the agents' commitments to one another. In representing commitments in the event calculus, we formalize commitment operations and domain-independent reasoning rules as axioms to capture the evolution of commitments. We also provide a means to specify protocol-specific axioms through the agents' actions. These axioms enable agents to reason about their actions explicitly to flexibly accommodate the exceptions and opportunities that may arise at run time. This reasoning is implemented using an event calculus planner that helps determine flexible execution paths that respect the given protocol specifications.     

Integration in industrial automation based on multi-agent systems using cultural algorithms for optimizing the coordination mechanisms

Integration in industrial automation can be approached from the theory of Distributed Artificial Intelligence. One approach is the modeling of different production units by agents that interact through interaction protocols, which are implemented following a coordination mechanism. Under this approach, integration in automation can be achieved through the optimization of implicit interactions in such mechanisms. This paper presents a strategy for integrating industrial processes based on Multi-Agent Systems (MAS), which consists of optimizing coordination mechanisms that implement conversations between agents, by using cultural algorithms. The cultural algorithm uses formal models of interaction protocols between agents, such as auction and tender, and the integration scheme comes from automation architectures based on MAS, to which their interactions are optimized. The proposed scheme enables data and service-oriented integration. The proposed strategy is applied in two industrial case studies related to the oil production process.     

Protocol Moderators as Active Middle-Agents in Multi-Agent Systems

Interaction protocols are widely recognized as an essential mechanism for coordination within multi-agent systems. There is thus a need for coordination models for specifying, validating, and implementing protocols, possibly open and concurrent, efficiently and reliably. This paper proposes such a model, which considers protocols as resources and each conversation among agents following the rules of a protocol as a well-identified process. To this end, a new kind of middle-agent, called Moderator, is introduced. A Moderator is in charge of monitoring a conversation so that it progresses according to the protocol rules, and provides agents with services to ease their involvement in the conversation. This model fits the organization-centered view of multi-agent systems as it strictly distinguishes the agent-level and the organization-level concerns with regard to interaction. In addition, the paper shows that this model is supported by a High-Level Petri Net language that covers all the steps of protocol engineering: design, validation, implementation. This paper presents this Moderator Coordination Model along four related dimensions: a conceptual model of protocols, a MAS architecture, a suitable modeling formalism, and an associated development process.