An Introduction to Simulation-Based Techniques for Automated Service Composition

This work is an introduction to the author's contributions to the SOC area, resulting from his PhD research activity. It focuses on the problem of automatically composing a desired service, given a set of available ones and a target specification. As for description, services are represented as finite-state transition systems, so to provide an abstract account of their behavior, seen as the set of possible conversations with external clients. In addition, the presence of a finite shared memory is considered, that services can interact with and which provides a basic form of communication. Rather than describing technical details, we offer an informal overview of the whole work, and refer the reader to the original papers, referenced throughout this work, for all details

Real-time forecasting of the April 11, 2012 Sumatra tsunami

The April 11, 2012, magnitude 8.6 earthquake off the northern coast of Sumatra generated a tsunami that was recorded at sea-level stations as far as 4800 km from the epicenter and at four ocean bottom pressure sensors (DARTs) in the Indian Ocean. The governments of India, Indonesia, Sri Lanka, Thailand, and Maldives issued tsunami warnings for their coastlines. The United States' Pacific Tsunami Warning Center (PTWC) issued an Indian Ocean-wide Tsunami Watch Bulletin in its role as an Interim Service Provider for the region. Using an experimental real-time tsunami forecast model (RIFT), PTWC produced a series of tsunami forecasts during the event that were based on rapidly derived earthquake parameters, including initial location and Mwp magnitude estimates and the W-phase centroid moment tensor solutions (W-phase CMTs) obtained at PTWC and at the U. S. Geological Survey (USGS). We discuss the real-time forecast methodology and how successive, real-time tsunami forecasts using the latest W-phase CMT solutions improved the accuracy of the forecast

Synthesis from Recursive-Components Libraries

Synthesis is the automatic construction of a system from its specification. In classical synthesis algorithms it is always assumed that the system is "constructed from scratch" rather than composed from reusable components. This, of course, rarely happens in real life. In real life, almost every non-trivial commercial software system relies heavily on using libraries of reusable components. Furthermore, other contexts, such as web-service orchestration, can be modeled as synthesis of a system from a library of components. In 2009 we introduced LTL synthesis from libraries of reusable components. Here, we extend the work and study synthesis from component libraries with "call and return"' control flow structure. Such control-flow structure is very common in software systems. We define the problem of Nested-Words Temporal Logic (NWTL) synthesis from recursive component libraries, where NWTL is a specification formalism, richer than LTL, that is suitable for "call and return" computations. We solve the problem, providing a synthesis algorithm, and show the problem is 2EXPTIME-complete, as standard synthesis.Comment: In Proceedings GandALF 2011, arXiv:1106.081

Integrating BDI agents with Agent-based simulation platforms

Agent-Based Models (ABMs) is increasingly being used for exploring and supporting decision making about social science scenarios involving modelling of human agents. However existing agent-based simulation platforms (e.g., SWARM, Repast) provide limited support for the simulation of more complex cognitive agents required by such scenarios. We present a framework that allows Belief-Desire Intention (BDI) cognitive agents to be embedded in an ABM system. Architecturally, this means that the "brains" of an agent can be modelled in the BDI system in the usual way, while the "body" exists in the ABM system. The architecture is exible in that the ABM can still have non-BDI agents in the simulation, and the BDI-side can have agents that do not have a physical counterpart (such as an organisation). The framework addresses a key integration challenge of coupling event-based BDI systems, with time-stepped ABM systems. Our framework is modular and supports integration off-the-shelf BDI systems with off-the-shelf ABM systems. The framework is Open Source, and all integrations and applications are available for use by the modelling community

Compliant Business Processes with Exclusive Choices from Agent Specification

We study the complexity of the Strategic Argumentation Problem for 2-player dialogue games where a player should decide what move (set of rules) to play at each turn in order to prove (dis- prove) a given thesis. We show that this is an NP-complete problem

Observações sôbre as manchas ferruginosas internas (chocolate), em tubérculos de batatinha Observations on the internal brown spot of irish potatoes

É comum observar-se, em diferentes variedades de batatinha (Solanum tuberosum L.), principalmente quando cultivadas no chamado "período das águas", setembro-fevereiro , a presença de manchas ferruginosas no interior dos tubérculos, vulgarmente conhecidas pela denominação de "chocolate". Com a finalidade de constatar qual a região da batatinha onde4 elas se localizam, e de correlacionar a presença das manchas aos característicos externo* tais como aspereza da película, presença de brotos novos necrosados e, ainda, com o tamanho e forma dos tubérculos, foram feitas observações em diversas variedades e em clones criados no Instituto Agronômico.<br>Observations were made with standard varieties and new clones of Irish potatoes (Solatium tuberosum L.) to determine the localization of internal brown spots ("Chocolate" disease) in the tubers. This disease is considered to be of physiological origin, and an attempt was made to correlate the internal brown spots with external characteristics of the tubers, such as size, shape, roughness of skin, and the presence of necrosis in young sprouts. The following results were obtained : a) the presence of internal brown spots appears to be closely related to the variety and weather conditions during the growing season ; varieties such as Konsuragis and Ultimus give high percentages of internal brown spots when grown in the socalled rainy season (September to February). They do not show these symptoms in the dry season (March to August) or under well controlled irrigation ; b) internal brown spots have been found to appear more frequently in the apex and middle of the tubers than in their base; c) a high correlation between rough skin and the presence of the disease in the tubers was noticed for varieties that have a tendency to show internal brown spots ; this was noticed even in case of tubers that due to unfavorable weather conditions showed two distinct phases of growth, one with a rough skin and the other with a smooth one ; brown spots could be seen only in the flash of that part of the tuber that had a rough skin ; d) in some instances the presence of necrosis in the young sprouts was also correlated with the presence of internal brown spots in the tubers e) potato tubers affected with the "chocolate" disease are hard and unfit for human consumption

The ARTS Real-Time Agent Architecture

Abstract—We present a new approach to providing soft realtime guarantees for Belief-Desire-Intention (BDI) agents. We define what it means for BDI agents to operate in real time, or to satisfy real-time guarantees. We then develop a model of real-time performance which takes into account the time by which a task should be performed and the relative priority of tasks, and identify the key stages in a BDI architecture which must be bounded for real-time performance. As an illustration of our approach we introduce a new BDI architecture, ARTS, which allows the development of agents that guarantee (soft) real-time performance. ARTS extends ideas from PRS and JAM to include goals and plans which have deadlines and priorities, and schedules intentions so as to achieve the largest number of high priority intentions by their deadlines

Morphological and genetic variability in an alien invasive mussel across an environmental gradient in South America

Adaptation is an essential step in the establishment and spread of alien species in new environments, with phenotypic plasticity or genetic variability often contributing to this success. The golden mussel Limnoperna fortunei is a biofouling mollusc native to Southeast Asia that was introduced to South America near the Río de la Plata estuary, Argentina, though the species has subsequently spread more than 2000 km upstream. We analyzed morphological and genetic variation in 24 introduced populations of L. fortunei across its South American range. Relative gill area and shell morphology differed significantly, even among geographically proximate populations. Differences in relative gill area were especially marked across the species\u27 range and were negatively correlated with total suspended solids. Whereas mean gill cilia length, filament width, and interfilamental ciliary junction distance did not differ significantly among populations, mean gill cilia density was significantly lower in populations from areas with high suspended solids. Conversely, morphological differences were not related to the number of haplotypes, haplotype diversity, or nucleotide diversity, based upon analyses of the mitochondrial cytochrome c oxidase subunit 1 gene. Our results indicate that introduced populations of golden mussels in South America exhibit pronounced morphological variation in shell and gill metrics that appear to result from developmental plasticity in relation to total suspended sediments, as has been observed in other mussel species. These adaptations may have facilitated spread of this species to a wide range of habitats. © 2014, by the Association for the Sciences of Limnology and Oceanography, Inc

Logical Foundations for a Rational BDI Agent Programming Language (Extended Version) ⋆

Abstract. To provide efficiency, current BDI agent programming languages with declarative goals only support a limited form of rationality – they ignore other concurrent intentions of the agent when selecting plans, and as a consequence, the selected plans may be inconsistent with these intentions. In this paper, we develop logical foundations for a rational BDI agent programming framework with prioritized declarative goals that addresses this deficiency. We ensure that the agent’s chosen declarative goals and adopted plans are consistent with each other and with the agent’s knowledge. We show how agents specified in our language satisfy some key rationality requirements.