Showing papers on "Contract Net Protocol published in 2012"

Agent-Based Cloud Computing

Abstract: Agent-based cloud computing is concerned with the design and development of software agents for bolstering cloud service discovery, service negotiation, and service composition. The significance of this work is introducing an agent-based paradigm for constructing software tools and testbeds for cloud resource management. The novel contributions of this work include: 1) developing Cloudle: an agent-based search engine for cloud service discovery, 2) showing that agent-based negotiation mechanisms can be effectively adopted for bolstering cloud service negotiation and cloud commerce, and 3) showing that agent-based cooperative problem-solving techniques can be effectively adopted for automating cloud service composition. Cloudle consists of 1) a service discovery agent that consults a cloud ontology for determining the similarities between providers' service specifications and consumers' service requirements, and 2) multiple cloud crawlers for building its database of services. Cloudle supports three types of reasoning: similarity reasoning, compatibility reasoning, and numerical reasoning. To support cloud commerce, this work devised a complex cloud negotiation mechanism that supports parallel negotiation activities in interrelated markets: a cloud service market between consumer agents and broker agents, and multiple cloud resource markets between broker agents and provider agents. Empirical results show that using the complex cloud negotiation mechanism, agents achieved high utilities and high success rates in negotiating for cloud resources. To automate cloud service composition, agents in this work adopt a focused selection contract net protocol (FSCNP) for dynamically selecting cloud services and use service capability tables (SCTs) to record the list of cloud agents and their services. Empirical results show that using FSCNP and SCTs, agents can successfully compose cloud services by autonomously selecting services.

Service-oriented architecture for ontologies supporting multi-agent system negotiations in virtual enterprise

Abstract: This paper offers a service-oriented architecture (SOA) for ontology-based multi-agent system (MAS) negotiations in the context of virtual enterprises (VEs). The objective of this paper is fourfold. First, it is to design a SOA which utilizes ontology and MAS to provide a distributed and interoperable environment for automated negotiations in VE. In this architecture, individual ontologies for both the VE initiator and its potential partners are constructed to describe and store resources and service knowledge. Second, a series of semantic ontology matching methods are developed to reach agents' interoperability during the negotiation process. Third, correspondence-based extended contract net protocol is presented, which provides basic guidelines for agents' reaching mutual understandings and service negotiation. Last, a fuzzy set theory based knowledge reuse approach is proposed to evaluate the current negotiation behaviors of the VE partners. A walkthrough example is presented to illustrate the methodologies and system architecture proposed in this paper.

Experimental analysis of contract net protocol in multi-robot task allocation

Abstract: - This paper focuses on the experimental analysts of Contract NET protocol for Multi-Robot task allocation. The problem domain consists of multiple vacuum cleaning robots that need to cooperate for cleaning an area that is beyond the capabilities of a single robot. A robot simulator has been used to experiment with various area and robot locations, and the summary of the effort required to process the tasks has been recorded. Experimental results show that using Contract NET protocol alone is not sufficient to achieve optimal results in task allocation. A more advanced strategy with or without involving the Contract NET protocol is required. Possible strategies are outlined and their analysis is the subject of the future work.

Agent-based cloud workflow execution

Abstract: Cloud computing offers an economical and feasible solution for scientific workflow applications requiring large amounts of computational resources and expensive hardware. Supporting Cloud workflow execution involves: i allocating and composing a collection of Cloud resources, and ii coordinating distributed and self-interested participants. The contributions of this research are: i proposing an agent-based approach for supporting workflow execution in one or multiple Clouds, ii defining Petri-net based methodologies to design workflows and Cloud resources that sustain concurrent and parallel management of workflows, iii implementing an agent-based testbed to simulate distributed workflow execution, and iv providing empirical evidence to demonstrate the effectiveness and efficiency of agent-based Cloud workflow execution. The agents are endowed with distributed algorithms, e.g., contract net protocol, to allocate and compose Cloud resources based on workflow requirements. Simulation results demonstrated that: i Agents effectively executed with a 100% success rate workflows autonomously, even when dealing with concurrent workflow executions, ii task parallelization was efficiently achieved in randomly created workflows with different levels of parallelism and ordering constraints, iii workflow execution was efficiently achieved since the makespan and number of messages exchanged increased linearly with the number of tasks.

A New Agents-Based Model for Dynamic Job Allocation in Manufacturing Shopfloors

Abstract: Market-based mechanisms such as the contract net protocol (CNP) are very popular for dynamic job allocation in distributed manufacturing control and scheduling. The CNP can be deployed with different configurations of the system elements. Every configuration corresponds to a basic or a hybrid topology. The subject of topology is generally discussed in the field of “distributed systems.” Inspired from the notion of topology in the distributed systems, this paper proposes a ring-like model as a competitor for the web-like CNP-based job allocation within the concept of holonic manufacturing systems. Details of the algorithm for scheduling and assignment of jobs to resources in the ring structure is presented and its performance is compared with both CNP-based distributed model, and the centralized conventional scheduling of a real manufacturing case study involving a major turbine production plant. Comparison of performance indicators such as time and cost of operations shows that the distributed models clearly outperform the conventional practice with meaningful impact on the production economy. As a possible implementation strategy, a hybrid switching model, composed of both competing models, is proposed.

Multi-time scale microgrid energy optimizing management system structure and method

Abstract: The invention relates to a multi-time scale microgrid energy optimizing management system structure and method. The system adopts an MAS (Mobile Agent Server) system framework which comprises a plurality of distributive power agents (Agent), a plurality of distributive power Agents, a plurality of demand response agents (Agent), a plurality of user Agents and a main electric grid dispatching Agents, wherein the Agents are collaborated and coordinated with an MAS system served as a frame based on the real-time capacity of a dynamic contract net protocol and ultra-short-term microgrid energy optimization; in case an important even that the Agents are triggered via an electric grid, the Agents are internally collaborated and collaborated with different Agents based on a set contract net coordination strategy, so as to ensure a microgrid system can run in an optimal mode under the rules of safety and speed. By adopting the structure and method provided by the invention, the gaps of the distributive power generation caused by the intermittency and the discontinuity can be filled, the robustness of the system can be improved, the response time can be reduced, the environmental benefit can be ensured as well as the economy of the electric grid in a full running period.

Pheromone-based coordination for manufacturing system control

Abstract: A pheromone-based coordination approach, which comes from the collective behavior of ant colonies for food foraging, is applied to control manufacturing system in this paper, aiming at handling dynamic changes and disturbances. The pheromone quantum of manufacturing cell is calculated inversely proportional to the cost, which can guarantee a minimal cost to process the orders. This approach has the capacity for optimization model to automatically find efficient routing paths for processing orders and to reduce communication overhead which exists in contract net protocol in shop floor control system. A prototype system is developed, and experiments confirm that pheromone-based coordination approach has excellent control performance and adaptability to disturbances in shop floor.

On a holonic adaptive plan-based architecture: planning scheme and holons’ life periods

Abstract: Holonic manufacturing execution systems still raise problems regarding modelling, design, testing and implementation of holons. This paper aims at obtaining an improved holonic scheme based on some underlying points: the types of holons used in PROSA holonic reference architecture, the contract net protocol for holons’ coordination and the BDI agents as software components. The addressed issues concern a solution for the proper interaction between several holons and the obtaining of certain patterns capable of guiding the design and implementation of holons. To be able to analyze holons’ behaviour and holonic system performance, a modelling approach using specific points of the planning theory and Petri nets was developed. The proposed formalization better clarifies how a holon’s components have to be devised, and clearly separates the holons’ construction and operation. Some drawbacks that can appear in a holonic system are revealed both by the holons’ models and by the conducted simulation experiments. The solution to the discovered weak points is based on the coordination provided by a centralized component and a specific way of conducting the bidding process. With these improvements a holonic adaptive plan-based architecture is obtained, this paper presenting the aspects regarding holons design and testing, while the problems on holonic agents’ reasoning procedure and details of their implementation are only briefly tackled.

Platform-level Distributed Warfare Model-based on Multi-Agent System Framework

Abstract: The multi-agent paradigm has become a useful tool in solving military problems. However, one of key challenges in multi-agent model for distributed warfare could be how to describe the microcosmic tactical warfare platforms actions. In this paper, a platform-level distributed warfare model based on multi-agent system framework is designed to tackle this challenge. The basic ideas include: Establishing multi-agent model by mapping from tactical warfare system’s members, i.e., warfare platforms, to respective agents; performing task decomposition and task allocation by using task-tree decomposition method and improved contract net protocol model technique; and implementing simulation by presenting battlefield terrain environment analysis algorithm based on grid approach. The simulation demonstration results show that our model provides a feasible and effective approach to supporting the abstraction and representation of microcosmic tactical actions for complex warfare system. Defence Science Journal, 2012, 62(1), pp.180-186 , DOI:http://dx.doi.org/10.14429/dsj.62.964

Composing web services enacted by autonomous agents through agent-centric contract net protocol

Abstract: Context: Agents are considered as one of the fundamental technologies underlying open and dynamic systems that are largely enabled by the semantic web and web services. Recently, there is a trend to introduce the notion of autonomy empowered by agents into web services. However, it has been argued that the characteristics of autonomy will make agents become available intermittently and behave variedly over time, which therefore increase the complexity on devising mechanisms for composing services enacted by autonomous agents. Objective: In this work, we propose an extension to Contract Net protocol, called Agent-centric Contract Net Protocol (ACNP), as a negotiation mechanism with three key features for composing web services enacted by autonomous agents. Method: (1) A matchmaking mechanism embedded in a middle agent (as a service matchmaker) for discovering web services that are available intermittently is presented based on the concept of agent roles; (2) A selection algorithm based on risk-enabled reputation model (REAL) embedded in a manager agent (as a service composer) is introduced to serve a basis for selecting web services with variant performance; and (3) A negotiation mechanism between a manager agent and contractor agents (as atomic services) is devised and enables both a service composer and the atomic services to request, refuse or agree on adapting changes of services. Results: The problem of assembling a computer is discussed in this paper. Conclusion: It is increasingly recognised that web services would become more autonomous by introducing diverse agent technologies to better constitute more complex systems in open and dynamic environments. As web service technologies are best exploited by composite services, it is imperative to devise mechanisms for composing services of autonomy.

HAPBA – A Holonic Adaptive Plan-Based Architecture

Abstract: This contribution reveals how the planning and coordination processes in Holonic Manufacturing Execution Systems entail the need of a centralized component, under the form of a staff holon. By using appropriate models (both monochrome and coloured Petri nets) and certain aspects of planning techniques in Artificial Intelligence, a PROSA based implementation is considered. In the obtained holonic scheme, named HAPBA, the solution of the manufacturing goals is attained by holons’ cooperation, according to an enhanced form of the Contract Net Protocol, so that certain drawbacks that are possible to appear in a holonic approach are avoided. Theoretical and experimental arguments are supporting the proposed solution.

A Novel Approach to Selecting Contractor in Agent-based Multi-sensor Battlefield Reconnaissance Simulation

Abstract: This paper presents a novel approach towards showing how contractor in agent-based simulation for complex warfare system such as multi-sensor battlefield reconnaissance system can be selected in Contract Net Protocol (CNP) with high efficiency. We first analyze agent and agent-based simulation framework, CNP and collaborators, and present agents interaction chain used to actualize CNP and establish agents trust network. We then obtain contractor's importance weight and dynamic trust by presenting fuzzy similarity-based algorithm and trust modifying algorithm, thus we propose contractor selecting approach based on maximum dynamic integrative trust. We validate the feasibility and capability of this approach by implementing simulation, analyzing compared results and checking the model.

Agent-based manufacturing control based on distributed bid selection and publish-subscribe messaging: a simulation case study

Abstract: Bidding-based negotiation schemes play a major role in multi-agent manufacturing systems research. Despite some concerns with message congestion, researchers have been proposing and studying negotiation schemes based on the contract net protocol (CNP). On the other hand, research in robotics has considered a variant of CNP based on publish-subscribe messaging designed for multi-robot coordination. A distinct feature of this variant involves distributing the bid evaluation and selection functions among robot agents. This paper discusses our adaptation of this design variant for multi-agent manufacturing systems and examines its performance implications. Using discrete-event simulation, we study how the adapted CNP design can help address the message congestion problem by cutting down on negotiation slack time. Our case study results show that it can enhance the resilience of the agent negotiation process to message congestion, thereby contributing to the overall performance of a multi-agent manufacturing s...

An Interaction Protocol for Mutual Assistance in Agent Teamwork

Abstract: This paper proposes and explores an interaction protocol for incorporating helpful behavior into agent teamwork. In the proposed Mutual Assistance Protocol (MAP), an agent can directly assist a teammate who requests help, provided that the two agents jointly determine, based on their individual beliefs, that the expected outcome of the help act is in the interest of the team. This distributed decision is reached through a bidding sequence similar to the one in the Contract Net Protocol. The deliberation about help is approximate in that each agent only assesses the team impact of the change to its own individual plan. The paper introduces two versions of the protocol: Action MAP, in which the helper performs an action within a teammate's individual plan, and Resource MAP, in which one or more helpers provide resources to a teammate. Both versions include refinements for the handling of simultaneous help requests. A cooperative game simulation demonstrates the advantages of Action MAP over action help protocols that use unilateral decision mechanisms, and over teamwork scenarios without help. The experiments show how the team performance depends on: the teammates' mutual awareness of each other's abilities, dynamic disturbance in the environment, communication costs, and computation costs.

Model Checking Logics of Social Commitments for Agent Communication

Abstract: This thesis is about specifying and verifying communications among autonomous and possibly heterogeneous agents, which are the key principle for constructing effective open multi-agent systems (MASs). Effective systems are those that successfully achieve applicability, feasibility, error-freeness and balance between expressiveness and verification efficiency aspects. Over the last two decades, the MAS community has advocated social commitments, which successfully provide a powerful representation for modeling communications in the figure of business contracts from one agent to another. While modeling communications using commitments provides a fundamental basis for capturing flexible communications and helps address the challenge of ensuring compliance with specifications, the designers and business process modelers of the system as a whole cannot guarantee that an agent complies with its commitments as supposed to or at least not wantonly violate or cancel them. They may still wish to first formulate the notion of commitment-based protocols that regulate communications among agents and then establish formal verification (e.g., model checking) by which compliance verification in those protocols is possible. In this thesis, we address the aforementioned challenges by firstly developing a new branching-time temporal logic---called ACTL*c---that extends CTL* with modal operators for representing and reasoning about commitments and all associated actions. The proposed semantics for ACL (agent communication language) messages in terms of commitments and their actions is formal, declarative, meaningful, verifiable and semi-computationally grounded. We use ACTL*c to derive a new specification language of commitment-based protocols, which is expressive and suitable for model checking. We introduce a reduction method to formally transform the problem of model checking ACTL*c to the problem of model checking GCTL* so that the use of the CWB-NC model checker is possible. We prove the soundness of our reduction method and implement it on top of CWB-NC. To check the effectiveness of our reduction method, we report the verification results of the NetBill protocol and Contract Net protocol against some properties. In addition to the reduction method, we develop a new symbolic algorithm to perform model checking ACTL*c. To balance between expressiveness and verification efficiency, we secondly adopt a refined fragment of ACTL*c, called CTLC, an extension of CTL with modalities for commitments and their fulfillment. We extend the formalism of interpreted systems introduced to develop MASs with shared and unshared variables and considered agents' local states in the definition of a full-computationally grounded semantics for ACL messages using commitments. We present reasonable axioms of commitment and fulfillment modalities. In our verification technique, the problem of model checking CTLC is reduced into the problems of model checking ARCTL and GCTL* so that respectively extended NuSMV and CWB-NC (as a benchmark) are usable. We prove the soundness of our reduction methods and then implement them on top of the extended NuSMV and CWB-NC model checkers. To evaluate the effectiveness of our reduction methods, we verified the correctness of two business case studies. We finally proceed to develop a new symbolic model checking algorithm to directly verify commitments and their fulfillment and commitment-based protocols. We analyze the time complexity of CTLC model checking for explicit models and its space complexity for concurrent programs that provide compact representations. We prove that although CTLC extends CTL, their model checking algorithms still have the same time complexity for explicit models, and the same space complexity for concurrent programs. We fully implement the proposed algorithm on top of MCMAS, a model checker for the verification of MASs, and then check its efficiency and scalability using an industrial case study.

A Timed Colored Petri-Net-based Modelling for Contract Net Protocol with Temporal Aspects

Abstract: Contract Net Protocol (CNP) is a high level communication protocol. It is one of the most widely used in multi-agent system (MAS) to resolve decentralized task allocation problem. The main aim of the protocol is to facilitate contract negotiation between a manager agent and many contractor agents. A lot of works have been done for the verification of the protocol and its extensions, but there still lacks a formalism for representing temporal interaction aspects which are an essential parameter in the protocol modeling. This paper proposes to use Timed Colored Petri Nets (TCPN) to model correctly and formally this temporal dimension often defined as interaction duration and message deadlines. We will verify by means of simulation techniques and state space analysis important properties namely model correctness, deadline respect, absence of deadlocks and livelocks, absence of dead code, agent terminal states consistency, concurrency and validity. Keywords-Negotiation protocols; Contract net protocol; Multiagent systems; Timed Colored Petri Nets.

Improvement and simulation of contract-net-based task allocation for multi-robot system

Abstract: Due to the shortage of ignoring the balance between the mission success rate and the executive ability of the whole system in the common contract net models, a threshold-limited load balance strategy for awarding is proposed. The mathematical model of negotiation process based on improved contract net is established. The conceptual model of the multi-robot system based on improved contract net is implemented by Colored Petri Nets (CPN), and its correctness and dynamic properties such as liveness property, home property and fairness property are validated by using CPN Tools. Simulation results show that this method can effectively improve the performance, and ensure the overall system load balance.

A Multiagent Based System for Resource Allocation and Scheduling of Distributed Projects

Abstract: In this paper, a multi agent based decentralized decision making approach is presented for allocating resources and scheduling of distributed multiple projects. The resource allocation and scheduling is performed cooperatively and collectively by a group of autonomous project agents, resource agents and a mediator agent. We propose a price mechanism that allows project agents to bid for the needed resources. A new contract net protocol (CNP) concept is used for negotiations and coordination among the agents. This approach is successfully applied on an example problem.

Research on Cooperation of Multiple Agent Based on Contract-Net Protocol

Abstract: Classical Contract-Net protocol among the multi-Agent bidding can realize the cooperation of open heterogeneous environment. But MAS (Multiple Agent System) is a typical complex system. MAS's open, distributed and dynamic characteristics make the MAS environment filled with a lot of indeterminate factors, lead to surge in network traffic and negotiation deadlock. To solve these problems, this paper introduces the trust level domain and reputation mechanism to establish trust and reputation of the Contract-Net model. The model based on the history of cooperation experience in multi-Agent can effectively reduce network traffic, improve the efficiency and cooperation real-time of MAS.

Modeling Temporal Aspects of Contract Net Protocol Using Timed Colored Petri Nets

Abstract: Contract Net Protocol (CNP) is a high level communication protocol. It is one of the most widely used protocols in multi-agent system (MAS) to resolve decentralized task allocation problem. The main aim of the protocol is to facilitate contract negotiation between a manager agent and many contractor agents. A lot of work has been done for the verification of the protocol and its extensions, but there still a lack of a formalism for representing temporal interaction aspects which are an essential parameter in modeling the protocol . This paper proposes to use Timed Colored Petri Nets (TCPN) to model correctly and formally this temporal dimension often defined as interaction duration and message deadlines. We will use simulation techniques and state space analysis to verify important properties namely model correctness, deadline respect, absence of deadlocks and livelocks, absence of dead code, agent terminal states consistency, concurrency and validity.

Developing reliability model in contract net protocol

Abstract: Contract Net Protocol (CNP) is a task sharing/interaction protocol consisting of a collection of nodes called software agents purposely used for communication necessitated in a distributed multi agent environment. The conventional FIPA CNP allows the initiator agent to allocate task to contractor agents but does not allow the evaluation of reliability of contractors. In this paper we concentrate on the reliability of contractor agents that facilitates the initiator agent for awarding the task to optimal/best contractor. In this work we proposed a Reliability Model (RM) in the conventional CNP. Development of Reliability Model (RM) in conventional CNP will ensure the reliability of agents which is more decisive

Performance of Time-Bound Negotiation in Agent-Based Manufacturing Control

Abstract: Agent-based software technology plays an impor- tant role in the manufacturing industry for achieving agility. Shop floor control applications can be designed based on the paradigm of agent negotiation to cope with variabilities and disturbances in the production environment. This often involves the contract net protocol (CNP) and previous research has suggested that the timing parameters of CNP can affect significantly the performance of agent negotiation. This work extends our knowledge in this area of research by considering the performance effects of the combinatorial variations of these parameters in a discrete-event simulation case study. The results provide not only a deeper understanding of the time-bound agent negotiation process, but also insights into the performance fine-tuning of CNP-based control schemes. Index Terms—multi-agent systems; negotiation protocol; sim- ulation; work-in-progress; cycle time

Collaborative target classification with multiagent system in wireless multimedia sensor networks

Abstract: Recent technological advances in hardware design and wireless communications, together with the availability of low cost microphones and video camera, have stimulated the emergence of wireless multimedia sensor networks (WMSNs). This paper proposes to explore such novel approaches as inspired by multi-agent system (MAS) researches that conduct systematic investigation of interaction between autonomous entities. Within the MAS framework, a hierarchical WMSN architecture is established and swarm intelligence is introduced to facilitate its formation. Contract net protocol is employed to achieve efficient resource allocation among the sensor nodes for the purpose of intruding target classification. To make the best global decision, the mechanism of committee voting is exploited to combine all the individual decisions. The supervised machine learning techniques of Gaussian process classifier is presented for investigating the performance of the proposed hierarchical WMSN architecture. Simulation experiments with real-world data have been extensively performed to evaluate the proposed architecture, resource allocation and decision fusion mechanisms, and the results show that the proposed MAS approaches are effective and efficient.

A Study on the Agent-Based Vehicles Dispatching Optimization at Container Terminals

Abstract: This paper mainly concentrated on the method of improving the dispatching trucks working at a container terminal and built the multi-agent model for the dispatching job. The contract net protocol was taken as the communication ones among agents, and the analytic hierarchy process was also applied for the decision support for container trucks dispatching.

Goal deliberated agent architecture for multi-strategy selection in automated negotiation

Abstract: The strategy selection is very important for agent to achieve better negotiation outcomes in the automated negotiation research. To address the issue, this paper focuses on operationalizing agent's independent decision-making process through the design of a goal directed negotiation model, based on the classical belief-desire-intention agent theory. We formally define the automated negotiation agent's concept model, and design the abstract architecture, which can be properly realized using the existing software technology and the contract net protocol specifications. Grounded on the design of goal deliberation process, the model can support the agent's multi-strategy negotiation.

Aerial: A Framework to Support Human Decision Making in a Constrained Environment

Abstract: In this paper, we propose an architecture that uses a tender protocol, the Contract Net Protocol (CNP), to let human operators express their consent about the allocation of goals to Unmanned Aerial Vehicles (UAVs) in a constrained environment. The CNP has several good points: it has an appropriate level of automation, it is simple, it spares the bandwidth. But if bids are evaluated solely on the base of a numerical payoff, the CNP cannot fully convey human preference in complex situations. Thus, we extended and implemented the CNP within our framework, Aerial, to enable a more subjective human feedback. We detail how we build the bids and how we filter them to not flood the user. We also explain how we enable a dependable commitment in a dynamic context when the award time is not accurately foreseen.

Negotiation Platform for Personalised Advertising

Abstract: This paper describes a multi-agent brokerage platform for near real time advertising personalisation organised in three layers: user interface, agency and marketplace. The personalisation is based on the classification of viewer profiles and advertisements (ads). The goal is to provide viewers with a personalised advertising alignment during programme intervals. The enterprise interface agents upload new ads and negotiation profiles to producer agents and new user and negotiation profiles to distributor agents. The agency layer is composed of agents that represent ad producer and media distributor enterprises as well as the market regulator. The enterprise agents offer data upload and download operations as Web Services and register the specification of these interfaces at an UDDI registry for future discovery. The market agent supports the registration and deregistration of enterprise delegate agents at the marketplace. This paper addresses the marketplace layer, an agent-based negotiation platform per se, where delegates of the relevant advertising agencies and programme distributors negotiate to create the advertising alignment that best fits a viewer profile and the advertising campaigns available. The whole brokerage platform is being developed in JADE, a multi-agent development platform. The delegate agents download the negotiation profile and upload the negotiation results from / to the corresponding enterprise agent. In the meanwhile, they negotiate using the Iterated Contract Net protocol. All tools and technologies used are open source.