Some factors influencing eclosion and early postembryonic development in Schistocerca gregaria (Forska?l)-Orthoptera : Acrididae

Imperial Users onl

Evidence for spreading in the lower Kam Group of the Yellowknife greenstone belt: Implications for Archaean basin evolution in the Slave Province

The Yellowknife greenstone belt is the western margin of an Archean turbidite-filled basin bordered on the east by the Cameron River and Beaulieu River volcanic belts (Henderson, 1981; Lambert, 1982). This model implies that rifting was entirely ensialic and did not proceed beyond the graben stage. Volcanism is assumed to have been restricted to the boundary faults, and the basin was floored by a downfaulted granitic basement. On the other hand, the enormous thickness of submarine volcanic rocks and the presence of a spreading complex at the base of the Kam Group suggest that volcanic rocks were much more widespread than indicated by their present distribution. Rather than resembling volcanic sequences in intracratonic graben structures, the Kam Group and its tectonic setting within the Yellowknife greenstone belt have greater affinities to the Rocas Verdes of southern Chile, Mesozoic ophiolites, that were formed in an arc-related marginal basin setting. The similarities of these ophiolites with some Archean volcanic sequences was previously recognized, and served as basis for their marginal-basin model of greenstone belts. The discovery of a multiple and sheeted dike complex in the Kam Group confirms that features typical of Phanerozoic ophiolites are indeed preserved in some greenstone belts and provides further field evidence in support of such a model

handling, declarative goals, and planning

A BDI agent programming language with failur

Exploring the adaptive capacity of emergency management using agent based modelling

This project aimed to explore the suitability of Agent Based Modelling and Simulation (ABMS) technology in assisting planners and policy makers to better understand complex situations with multiple interacting aspects. The technology supports exploration of the impact of different factors on potential outcomes of a scenario, thus building understanding to inform decision making. To concretise this exploration a specific simulation tool was developed to explore response capacity around flash flooding in an inner Melbourne suburb, with a focus on sandbag depots as an option to be considered.The three types of activities delivered by this project to achieve its objectives were the development of an agent-based simulation, data collection to inform the development of the simulation and communication and engagement activities to progress the work. Climate change is an area full of uncertainties, and yet sectors such as Emergency Management and many others need to develop plans and policy responses regarding adaptation to these uncertain futures. Agent Based Modelling and Simulation is a technology which supports modelling of a complex situation from the bottom up, by modelling the behaviours of individual agents (often representing humans) in various scenarios. By running simulations with different configurations it is possible to explore and analyse a very broad range of potential options, providing a detailed understanding of potential risks and outcomes, given particular alternatives. This project explored the suitability of this technology for use in assessing and developing the capacity of the emergency response sector, as it adapts to climate change. A simulation system was developed to explore a particular issue regarding protection of property in a suburb prone to flash flooding. In particular the option of providing sandbag depots was explored. Simulations indicated that sandbag depots provided by CoPP or VicSES were at this time not a viable option. The simulation tool was deemed to be very useful for demonstrating this to community members as well as to decision makers. An interactive game was also developed to assist in raising awareness of community members about how to sandbag their property using on-site sandbags. The technology was deemed to be of great potential benefit to the sector and areas for further work inorder to realise this benefit were identified. In addition to developing awareness of useful technology, this project also demonstrated the critical importance of interdisciplinary team work, and close engagement with stakeholders and end users, if valuable technology uptake is to be realised. &nbsp

A BDI agent programming language with failure handling, declarative goals, and planning

Agents are an important technology that have the potential to take over contemporary methods for analysing, designing, and implementing complex software. The Belief- Desire-Intention (BDI) agent paradigm has proven to be one of the major approaches to intelligent agent systems, both in academia and in industry. Typical BDI agent-oriented programming languages rely on user-provided ''plan libraries'' to achieve goals, and online context sensitive subgoal selection and expansion. These allow for the development of systems that are extremely flexible and responsive to the environment, and as a result, well suited for complex applications with (soft) real-time reasoning and control requirements. Nonetheless, complex decision making that goes beyond, but is compatible with, run-time context-dependent plan selection is one of the most natural and important next steps within this technology. In this paper we develop a typical BDI-style agent-oriented programming language that enhances usual BDI programming style with three distinguished features: declarative goals, look-ahead planning, and failure handling. First, an account that mixes both procedural and declarative aspects of goals is necessary in order to reason about important properties of goals and to decouple plans from what these plans are meant to achieve. Second, lookahead deliberation about the effects of one choice of expansion over another is clearly desirable or even mandatory in many circumstances so as to guarantee goal achievability and to avoid undesired situations. Finally, a failure handling mechanism, suitably integrated with both declarative goals and planning, is required in order to model an adequate level of commitment to goals, as well as to be consistent with most real BDI implemented systems

Prioritisation mechanisms to support incremental development of agent systems

It is often necessary to partition a project into different priority levels and to develop incrementally. This paper presents a mechanism whereby a developer can prioritise scenarios on a five point scale, leading to automated, coherent partitioning of all required design entities, according to the three IEEE defined priority levels of essential, conditional and optional, which are used in many companies. This allows for automated support to guide the developer as to what design artefacts need to be developed at each phase. The developer can indicate the relative sizes desired for the three partitions and the algorithm described will attempt to get as close to this as possible. It is also possible to move items manually to achieve better sized partitions, as long as priority orderings are not violated. The approach is fast and easy to apply at various times during development, as needed

Systematic incremental development of agent systems using Prometheus

This paper presents a mechanism for dividing an agent oriented application into the three IEEE defined scoping levels of essential, conditional and optional. This mechanism is applied after the initial system specification, and is then used to direct incremental development with three separate releases. The scoping described can be applied at any stage of a project, in order to guide consistent scoping back if such is needed. The three levels of scoping that are used are consistent with the approach used in many companies. The approach to scoping requires that scenarios are prioritised manually on a five point scale. All other aspects are then prioritised automatically, based on this information. The approach used allows a developer to indicate what size partitions - based on number of scenarios - are required for each scoping level. The mechanisms are applied to the Prometheus development methodology and are integrated into the Prometheus design tool (PDT)

A component-based approach to automated web service composition

There is great promise in the idea of having Web services available on the Internet, that can be flexibly composed to achieve more complex services, which can themselves then also be used as components in other contexts. However it is challenging to realise this idea, without essentially programming the composition using some process language such as WS-BPEL or OWL-S process descriptions. This paper presents a mechanism for specifying the external interface to composite and component services, and then deriving an appropriate internal model to realise a functioning composition. We present a conversation specification language for defining interaction protocols and investigate the issue of synchronous and asynchronous communication between the composite service and the component service

Internet collaboration and service composition as a loose form of teamwork

This paper describes Web service composition as a form of teamwork, where the Web services are team members in a loose collaboration. We argue that newer hierarchical teamwork models are more appropriate for Web service composition than the traditional models involving joint beliefs and joint intentions. We describe our system for developing and executing Web service compositions as team plans in JACK Teams,((TM) 1) and discuss the relationships between this approach and service orchestration languages such as Business Process Execution Language for Web Services (BPEL4WS). We discuss briefly how the use of Al planning can also be incorporated into this model, and identify some of the research issues involved. Incorporating Web service compositions into a mature Belief Desire Intention (BDI) agent team framework allows for integration of Web services seamlessly into a powerful application execution paradigm that supports sophisticated reasoning

Searching for joint gains in automated negotiations based on multi-criteria decision making theory

It is well established by conflict theorists and others that successful negotiation should incorporate "creating value" as well as "claiming value." Joint improvements that bring benefits to all parties can be realised by (i) identifying attributes that are not of direct conflict between the parties, (ii) tradeoffs on attributes that are valued differently by different parties, and (iii) searching for values within attributes that could bring more gains to one party while not incurring too much loss on the other party. In this paper we propose an approach for maximising joint gains in automated negotiations by formulating the negotiation problem as a multi-criteria decision making problem and taking advantage of several optimisation techniques introduced by operations researchers and conflict theorists. We use a mediator to protect the negotiating parties from unnecessary disclosure of information to their opponent, while also allowing an objective calculation of maximum joint gains. We separate out attributes that take a finite set of values (simple attributes) from those with continuous values, and we show that for simple attributes, the mediator can determine the Pareto-optimal values. In addition we show that if none of the simple attributes strongly dominates the other simple attributes, then truth telling is an equilibrium strategy for negotiators during the optimisation of simple attributes. We also describe an approach for improving joint gains on non-simple attributes, by moving the parties in a series of steps, towards the Pareto-optimal frontier