Modelling and analyzing adaptive self-assembling strategies with Maude

Building adaptive systems with predictable emergent behavior is a challenging task and it is becoming a critical need. The research community has accepted the challenge by introducing approaches of various nature: from software architectures, to programming paradigms, to analysis techniques. We recently proposed a conceptual framework for adaptation centered around the role of control data. In this paper we show that it can be naturally realized in a reflective logical language like Maude by using the Reflective Russian Dolls model. Moreover, we exploit this model to specify and analyse a prominent example of adaptive system: robot swarms equipped with obstacle-avoidance self-assembly strategies. The analysis exploits the statistical model checker PVesta

Internal states of model isotropic granular packings. I. Assembling process, geometry and contact networks

This is the first paper of a series of three, reporting on numerical simulation studies of geometric and mechanical properties of static assemblies of spherical beads under an isotropic pressure. Frictionless systems assemble in the unique random close packing (RCP) state in the low pressure limit if the compression process is fast enough, slower processes inducing traces of crystallization, and exhibit specific properties directly related to isostaticity of the force-carrying structure. The different structures of frictional packings assembled by various methods cannot be classified by the sole density. While lubricated systems approach RCP densities and coordination number z^*~=6 on the backbone in the rigid limit, an idealized "vibration" procedure results in equally dense configurations with z^*~=4.5. Near neighbor correlations on various scales are computed and compared to available laboratory data, although z^* values remain experimentally inaccessible. Low coordination packings have many rattlers (more than 10% of the grains carry no force), which should be accounted for on studying position correlations, and a small proportion of harmless "floppy modes" associated with divalent grains. Frictional packings, however slowly assembled under low pressure, retain a finite level of force indeterminacy, except in the limit of infinite friction.Comment: 29 pages. Published in Physical Review

Organisational Abstractions for the Analysis and Design of Multi-Agent Systems

The architecture of a multi-agent system can naturally be viewed as a computational organisation. For this reason, we believe organisational abstractions should play a central role in the analysis and design of such systems. To this end, the concepts of agent roles and role models are increasingly being used to specify and design multi-agent systems. However, this is not the full picture. In this paper we introduce three additional organisational concepts - organisational rules, organisational structures, and organisational patterns - that we believe are necessary for the complete specification of computational organisations. We view the introduction of these concepts as a step towards a comprehensive methodology for agent-oriented systems

Modelling and analyzing adaptive self-assembling strategies with Maude

Building adaptive systems with predictable emergent behavior is a challenging task and it is becoming a critical need. The research community has accepted the challenge by introducing approaches of various nature: from software architectures, to programming paradigms, to analysis techniques. We recently proposed a conceptual framework for adaptation centered around the role of control data. In this paper we show that it can be naturally realized in a reflective logical language like Maude by using the Reflective Russian Dolls model. Moreover, we exploit this model to specify, validate and analyse a prominent example of adaptive system: robot swarms equipped with self-assembly strategies. The analysis exploits the statistical model checker PVeStA

Stewardship of the evolving scholarly record: from the invisible hand to conscious coordination

The scholarly record is increasingly digital and networked, while at the same time expanding in both the volume and diversity of the material it contains. The long-term future of the scholarly record cannot be effectively secured with traditional stewardship models developed for print materials. This report describes the key features of future stewardship models adapted to the characteristics of a digital, networked scholarly record, and discusses some practical implications of implementing these models. Key highlights include: As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models. Past stewardship models were built on an "invisible hand" approach that relied on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections. Future stewardship of the evolving scholarly record requires conscious coordination of context, commitments, specialization, and reciprocity. With conscious coordination, local stewardship efforts leverage scale by collecting more of less. Keys to conscious coordination include right-scaling consolidation, cooperation, and community mix. Reducing transaction costs and building trust facilitate conscious coordination. Incentives to participate in cooperative stewardship activities should be linked to broader institutional priorities. The long-term future of the scholarly record in its fullest expression cannot be effectively secured with stewardship strategies designed for print materials. The features of the evolving scholarly record suggest that traditional stewardship strategies, built on an “invisible hand” approach that relies on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections, is no longer suitable for collecting, organizing, making available, and preserving the outputs of scholarly inquiry. As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models. Conscious coordination calls for stewardship strategies that incorporate a broader awareness of the system-wide stewardship context; declarations of explicit commitments around portions of the local collection; formal divisions of labor within cooperative arrangements; and robust networks for reciprocal access. Stewardship strategies based on conscious coordination involve an acceleration of an already perceptible transition away from relatively autonomous local collections to ones built on networks of cooperation across many organizations, within and outside the traditional cultural heritage community

The Diversity and Dynamics of Industrial Organisation: Transformation of Local Assemblers in the Vietnamese Motorcycle Industry

This paper focuses on an emerging arm's-length form of industrial organisation in the motorcycle industry, which had traditionally been characterised by tightly integrated form of organisation. By engaging in how this new form of organisation that emerged in China was transferred to Vietnam and evolved in the Vietnamese context, this paper seeks to illustrate how the rise of local firms in developing countries is driving the increased diversity and dynamics of industrial organisation in an industry that had previously been dominated by TNCs from developed countries.Motorcycles, industrial organisation, motorcycle industry, Asia, China, Vietnam

XSRL: An XML web-services request language

One of the most serious challenges that web-service enabled e-marketplaces face is the lack of formal support for expressing service requests against UDDI-resident web-services in order to solve a complex business problem. In this paper we present a web-service request language (XSRL) developed on the basis of AI planning and the XML database query language XQuery. This framework is designed to handle and execute XSRL requests and is capable of performing planning actions under uncertainty on the basis of refinement and revision as new service-related information is accumulated (via interaction with the user or UDDI) and as execution circumstances necessitate change

Practitioner requirements for integrated Knowledge-Based Engineering in Product Lifecycle Management.

The effective management of knowledge as capital is considered essential to the success of engineering product/service systems. As Knowledge Management (KM) and Product Lifecycle Management (PLM) practice gain industrial adoption, the question of functional overlaps between both the approaches becomes evident. This article explores the interoperability between PLM and Knowledge-Based Engineering (KBE) as a strategy for engineering KM. The opinion of key KBE/PLM practitioners are systematically captured and analysed. A set of ranked business functionalities to be fulfiled by the KBE/PLM systems integration is elicited. The article provides insights for the researchers and the practitioners playing both the user and development roles on the future needs for knowledge systems based on PLM