4,007 research outputs found
A multi-agent system with application in project scheduling
The new economic and social dynamics increase project complexity and makes scheduling problems more difficult, therefore scheduling requires more versatile solutions as Multi Agent Systems (MAS). In this paper the authors analyze the implementation of a Multi-Agent System (MAS) considering two scheduling problems: TCPSP (Time-Constrained Project Scheduling), and RCPSP (Resource-Constrained Project Scheduling). The authors propose an improved BDI (Beliefs, Desires, and Intentions) model and present the first the MAS implementation results in JADE platform.multi-agent architecture, scheduling, project management, BDI architecture, JADE.
Applying the business process and practice alignment meta-model: Daily practices and process modelling
Background: Business Process Modelling (BPM) is one of the most important phases of information system design. Business Process (BP) meta-models allow capturing informational and behavioural aspects of business processes. Unfortunately, standard BP meta-modelling approaches focus just on process description, providing different BP models. It is not possible to compare and identify related daily practices in order to improve BP models. This lack of information implies that further research in BP meta-models is needed to reflect the evolution/change in BP. Considering this limitation, this paper introduces a new BP meta-model designed by Business Process and Practice Alignment Meta-model (BPPAMeta-model). Our intention is to present a meta-model that addresses features related to the alignment between daily work practices and BP descriptions. Objectives: This paper intends to present a meta-model which is going to integrate daily work information into coherent and sound process definitions. Methods/Approach: The methodology employed in the research follows a design-science approach. Results: The results of the case study are related to the application of the proposed meta-model to align the specification of a BP model with work practices models. Conclusions: This meta-model can be used within the BPPAM methodology to specify or improve business processes models based on work practice descriptions
Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning
The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques
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Approximate and Compensate: A Method for Risk-Sensitive Meta-Deliberation and Continual Computation
We present a flexible procedure for a resource-bounded agent to allocate limited computational resources to on-line problem solving. Our APPROXIMATE AND COMPENSATE methodology extends a well-known greedy time-slicing approach to conditions in which performance profiles may be non-concave and there is uncertainty in the environment and/or problem-solving procedures of an agent. With this method, the agent first approximates problem-solving performance and problem parameters with standard parameterized models. Second, the agent computes a risk-management factor that compensates for the risk inherent in the approximation. The risk-management factor represents a mean-variance tradeoff that may be derived optimally off-line using any available information. Theoretical and experimental results demonstrate that APPROXIMATE AND COMPENSATE extends existing methods to new problems and expands the practical application of meta-deliberation.Engineering and Applied Science
Parsing of Spoken Language under Time Constraints
Spoken language applications in natural dialogue settings place serious
requirements on the choice of processing architecture. Especially under adverse
phonetic and acoustic conditions parsing procedures have to be developed which
do not only analyse the incoming speech in a time-synchroneous and incremental
manner, but which are able to schedule their resources according to the varying
conditions of the recognition process. Depending on the actual degree of local
ambiguity the parser has to select among the available constraints in order to
narrow down the search space with as little effort as possible.
A parsing approach based on constraint satisfaction techniques is discussed.
It provides important characteristics of the desired real-time behaviour and
attempts to mimic some of the attention focussing capabilities of the human
speech comprehension mechanism.Comment: 19 pages, LaTe
Mission-Phasing Techniques for Constrained Agents in Stochastic Environments.
Resource constraints restrict the set of actions that an agent can take, such that the agent might
not be able to perform all its desired tasks. Computational time limitations restrict the number of
states that an agent can model and reason over, such that the agent might not be able to formulate
a policy that can respond to all possible eventualities. This work argues that, in either
situation, one effective way of improving the agent's performance is to adopt a phasing strategy.
Resource-constrained agents can choose to reconfigure resources and switch action sets for handling
upcoming events better when moving from phase to phase; time-limited agents can choose to focus
computation on high-value phases and to exploit additional computation time during the execution of
earlier phases to improve solutions for future phases.
This dissertation consists of two parts, corresponding to the aforementioned resource constraints
and computational time limitations. The first part of the dissertation focuses on the development
of automated resource-driven mission-phasing techniques for agents operating in
resource-constrained environments. We designed a suite of algorithms which not only can find
solutions to optimize the use of predefined phase-switching points, but can also automatically
determine where to establish such points, accounting for the cost of creating them, in complex
stochastic environments. By formulating the coupled problems of mission decomposition, resource
configuration, and policy formulation into a single compact mathematical formulation, the presented
algorithms can effectively exploit problem structure and often considerably reduce computational
cost for finding exact solutions.
The second part of this dissertation is the design of computation-driven mission-phasing techniques
for time-critical systems. We developed a new deliberation scheduling approach, which can
simultaneously solve the coupled problems of deciding both when to deliberate given its cost, and
which phase decision procedures to execute during deliberation intervals. Meanwhile, we designed a
heuristic search method to effectively utilize the allocated time within each phase. As illustrated
in experimental results, the computation-driven mission-phasing techniques, which
extend problem decomposition techniques with the across-phase deliberation scheduling and
inner-phase heuristic search methods mentioned above, can help an agent generate a better
policy within time limit.Ph.D.Computer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/60650/1/jianhuiw_1.pd
Cooperative transportation scheduling : an application domain for DAI
A multiagent approach to designing the transportation domain is presented. The MARS system is described which models cooperative order scheduling within a society of shipping companies. We argue why Distributed Artificial Intelligence (DAI) offers suitable tools to deal with the hard problems in this domain. We present three important instances for DAI techniques that proved useful in the transportation application: cooperation among the agents, task decomposition and task allocation, and decentralised planning. An extension of the contract net protocol for task decomposition and task allocation is presented; we show that it can be used to obtain good initial solutions for complex resource allocation problems. By introducing global information based upon auction protocols, this initial solution can be improved significantly. We demonstrate that the auction mechanism used for schedule optimisation can also be used for implementing dynamic replanning. Experimental results are provided evaluating the performance of different scheduling strategies
An agent-based approach to assess driversâ interaction with pre-trip information systems.
This article reports on the practical use of a multi-agent microsimulation framework to address the issue of assessing driversâ
responses to pretrip information systems. The population of drivers is represented as a community of autonomous agents,
and travel demand results from the decision-making deliberation performed by each individual of the population as regards
route and departure time. A simple simulation scenario was devised, where pretrip information was made available to users
on an individual basis so that its effects at the aggregate level could be observed. The simulation results show that the
overall performance of the system is very likely affected by exogenous information, and these results are ascribed to demand
formation and network topology. The expressiveness offered by cognitive approaches based on predicate logics, such as the
one used in this research, appears to be a promising approximation to fostering more complex behavior modelling, allowing
us to represent many of the mental aspects involved in the deliberation process
Time-bounded distributed QoS-aware service configuration in heterogeneous cooperative environments
The scarcity and diversity of resources among the devices of heterogeneous computing
environments may affect their ability to perform services with specific Quality
of Service constraints, particularly in dynamic distributed environments where the
characteristics of the computational load cannot always be predicted in advance.
Our work addresses this problem by allowing resource constrained devices to cooperate
with more powerful neighbour nodes, opportunistically taking advantage
of global distributed resources and processing power. Rather than assuming that
the dynamic configuration of this cooperative service executes until it computes
its optimal output, the paper proposes an anytime approach that has the ability
to tradeoff deliberation time for the quality of the solution. Extensive simulations
demonstrate that the proposed anytime algorithms are able to quickly find a good
initial solution and effectively optimise the rate at which the quality of the current
solution improves at each iteration, with an overhead that can be considered
negligible
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