Extending Agent Languages for Autonomy

BDI agent languages provide a useful abstraction for complex systems comprised of interactive autonomous entities, but they have been used mostly in the context of single agents with a static plan library of behaviours invoked reactively. These languages provide a theoretically sound basis for agent design but are very limited in providing direct support for autonomy and societal cooperation needed for large scale systems. Some techniques for autonomy and cooperation have been explored in the past in ad hoc implementations, but not incorporated in any agent language. In order to address these shortcomings we extend the well known AgentSpeak(L) BDI agent language to include behaviour generation through planning, declarative goals and motivated goal adoption. We also develop a language-specific multiagent cooperation scheme and, to address potential problems arising from autonomy in a multiagent system, we extend our agents with a mechanism for norm processing leveraging existing theoretical work. These extensions allow for greater autonomy in the resulting systems, enabling them to synthesise new behaviours at runtime and to cooperate in non-scripted patterns.

Differential encoding technique for multi-antenna systems with correlated Rayleigh fading channels

Differential space-time modulation (DSTM) techniques developed for multi-antenna systems allow the receiver to detect the transmitted signal without the knowledge of the fading channels. It can be viewed as an extension of differential phase-shift keying (DPSK) in single antenna systems. In this paper, we derived the pairwise error probability upper bound of differential space-time coded systems with spatially correlated Rayleigh fading channels. Based on the performance analysis, we develop a novel DSTM scheme which can exploit the spatial correlation in the fading channels. It is found that by carefully designing the initial transmitted signal matrix, the performance of the differential space-time coded systems can be significantly improved.

Assessing sport management journals : a multi-dimensional examination

The rating of refereed journals has become important for academics and institutions as well as for sport management as a field of study. This paper argues that the dearth of a rating system in sport management works against the best interests of the development of the field. This paper presents a rating scheme for sport management journals, which replicates an earlier study of marketing journals, using weighted multi-dimensional perceptual ratings (Polonsky & Whitelaw, 2006). Forty-five senior sport management academics evaluated 13 journals on four criteria: journal prestige, contribution to theory, contribution to practice and contribution to teaching. Using the weighted scores of the four criteria for each journal and a supporting cluster analysis, four categories of journals were identified. The results of this study will assist academics as they argue the case for the quality of journals in which they publish. Further it facilitates evaluation of sport management journals in relation to one another on the basis of their overall ranking and their scores on the four individual criteria.

Economic evaluation alongside a phase II, multi-centre, randomised controlled trial of very early rehabilitation after stroke (AVERT)

BACKGROUND/PURPOSE: The effectiveness and costs of very early rehabilitation after stroke are unknown. This study assessed the cost effectiveness of very early mobilisation in addition to standard care (VEM) compared with standard care alone (SC). METHODS: Cost-effectiveness analysis alongside a phase II, multi-centre, randomised controlled trial (RCT) with blinded outcome assessments. Less than 24 h after stroke, patients were recruited from two stroke units and randomised to receive VEM or SC. The intervention continued until discharge or 14 days, whichever was sooner. The efficacy measure was a dichotomised modified Rankin Scale (mRS) at 3 months with mRS < or =2 representing good outcome. Costs were determined from medical records and patient interviews at 3, 6 and 12 months. National average (where available) or local costs were applied for the reference year 2004. Differences in mean total costs at 3 and 12 months were tested using t test assuming unequal variances. An incremental cost-effectiveness ratio was calculated and probabilistic uncertainty analysis was undertaken. RESULTS: The sample consisted of 38 VEM and 33 SC patients. A trend for good outcome with VEM compared to SC was found (adjusted OR 4.10, 95% CI 0.99-16.88, p = 0.051). Patients receiving VEM incurred significantly less costs at 3 months (AUD 13,559) compared with SC (AUD 21,860; p = 0.02). This difference in mean per patient total cost persisted at the 12-month assessment (VEM: AUD 17,564; SC: AUD 29,750; p = 0.03). VEM was found to be a 'dominant' (more effective, less cost) intervention when compared to SC at 3 months. CONCLUSION: These findings provide preliminary evidence that VEM is likely to be cost-effective. A large RCT is currently underway to confirm the cost effectiveness of VEM.

Optimising discrete event simulation models using a reinforcement learning agent

A reinforcement learning agent has been developed to determine optimal operating policies in a multi-part serial line. The agent interacts with a discrete event simulation model of a stochastic production facility. This study identifies issues important to the simulation developer who wishes to optimise a complex simulation or develop a robust operating policy. Critical parameters pertinent to 'tuning' an agent quickly and enabling it to rapidly learn the system were investigated.

Content-based video indexing for sports applications using integrated multi-modal approach

This thesis presents a research work based on an integrated multi-modal approach for sports video indexing and retrieval. By combining specific features extractable from multiple (audio-visual) modalities, generic structure and specific events can be detected and classified. During browsing and retrieval, users will benefit from the integration of high-level semantic and some descriptive mid-level features such as whistle and close-up view of player(s). The main objective is to contribute to the three major components of sports video indexing systems. The first component is a set of powerful techniques to extract audio-visual features and semantic contents automatically. The main purposes are to reduce manual annotations and to summarize the lengthy contents into a compact, meaningful and more enjoyable presentation. The second component is an expressive and flexible indexing technique that supports gradual index construction. Indexing scheme is essential to determine the methods by which users can access a video database. The third and last component is a query language that can generate dynamic video summaries for smart browsing and support user-oriented retrievals.

A privacy preserving e-payment scheme

Secure electronic payment is an integral part of e-commerce. The e-payment systems in current use require the revealing of the purchaser’s payment information to the seller, while purchasers are not always happy to subject the details of their payment information to possible misuse by sellers. As a result, the uptake of e-commerce is hampered from reaching its full potential. In this paper, we propose an online payment scheme which uses the traditional e-payment infrastructure but which reveals no payment information to the seller. This is done with only an incremental increase in computational power.

Multi-level virtual ring : cross-level name routing with embedded identifier in sensor network

This paper presents the Multi-level Virtual Ring (MVR), a new name routing scheme for sensor networks. MVR uses selection algorithm to identify sensor nodes' virtual level and uses Distribution Hash Table (DHT) to map them to the MVR, The address routing performs well in wired network, but it's not true in sensor network. Because when nodes are moving, the address of the nodes must be changed Further, the address routing needs servers to allocate addresses to nodes. To solve this problem, the name routing is being introduced, such as Virtual Ring Routing (VRR). MVR is a new name routing scheme, which improves the routing performance significantly by introducing the multi-level virtual ring and cross-level routing. Experiments show this embedded name routing is workable and achieves better routing performance.

The role of reflexive capability in relation to intellectual capital on multi international partnerships

This paper reports the results of an analysis of five Malaysian firms who have worked successfully on multi international partnerships and/or megaprojects. A case study methodology was employed to examine the barriers and successful strategies the firms used in decision making in various international markets. A common characteristic across the firms was the ability to self reflect and adapt their practices to different international conditions despite numerous differences between countries including cultural, social, project governance structures, regulatory, terminology and codes. A reflexive capability model developed from the social sciences theory of individual agent reflexivity was developed to explain the way in which firms as an entity can develop awareness, responsiveness and adaptability for long term success in diverse international markets. This paper builds upon an initial Australian study which developed the model grounded in empirical observations of internationalising design construction firms by presenting the results of a second study of Malaysian firms. Results indicate that the model of reflexivity capability is a useful way to interpret practices that are undertaken in multi partner relationships on larger more complex projects. Successful Malaysian firms within joint venture relationships display an ability to self reflect and adapt. This transformation process is critiqued in relation to the relationships between social, cultural and intellectual capital. Reflexive capability is a characteristic of the successful case study firms working within global models of practice. The reflexive capability model is explained in relation to common themes identified in relation to the management of intellectual capital in successful multi international partnerships and megaprojects.

Post processing of the hot torsion test results using a multi-dimensional modelling approach

A model selection scheme was extended to a multi-dimensional representation of the hot torsion test torque, twist and twist rate data to calculate partial derivatives of the torque data with respect to twist and twist rate. These enabled calculation of the instantaneous strain and strain rate hardening indices in the Fields and Backofen method. The concept of an iso-parametric shape function has been borrowed from the finite element method for adding twist rate as a dependant variable to the torque-twist models identified by the model selection scheme. Expressions to calculate the hardening indices, when employing a rational model of torsion data, were derived and presented. Subsequently, the models were used for post processing the data and determining hot strength behaviour, taking into account variations of strain and strain rate hardening indices during the deformation. To substantiate the technique, the hot flow behaviour of API-X70 micro-alloyed steel was determined using a range of hot torsion test data for the material. The flow stress obtained using the instantaneous hardening indices were compared with that obtained by the orthodox technique. For the investigated cases, the onset of dynamic recrystallization (DRX) predicted by the presented technique deviated considerably from those obtained when the average indices were used.

A digital watermarking scheme for Bezier surfaces

Owners and vendors are increasingly publishing their materials in digital form. Because such materials can be exactly copied, a mechanism is required that will protect the legitimate owners of these works, by providing proof of original ownership. Digital watermarking has now become one accepted method of establishing ownership of digital materials. The owner of a work embeds a pattern, called a digital watermark, in the content. This embedded watermark is normally undetectable, but its presence can be demonstrated by the owner of the work or his agent, thereby proving ownership. Digital watermarking has been used for many types of multimedia content, primarily audio, video and flat images. Recently, interest has been shown in applying digital watermarking schemes to 3D surfaces, in various formats. In this paper, we examine a method whereby a digital watermark can be embedded in a Bezier surface. A prototype watermarking method for such surfaces is presented, with some experimental results, and a discussion of directions for future research.

A flexible receiver-driven cache replacement scheme for continuous media objects in best-effort networks

In this paper, we investigate the potential of caching to improve quality of reception (QoR) in the context of continuous media applications over best-effort networks. Specifically, we investigate the influence of parameters such as loss rate, jitter, delay and area in determining a proxy's cache contents. We propose the use of a flexible cost function in caching algorithms and develop a framework for benchmarking continuous media caching algorithms. The cost function incorporates parameters in which, an administrator and or a client can tune to influence a proxy's cache. Traditional caching systems typically base decisions around static schemes that do not take into account the interest of their receiver pool. Based on the flexible cost function, an improvised Greedy Dual (GD) algorithm called GD-multi has been developed for layered multiresolution multimedia streams. The effectiveness of the proposed scheme is evaluated by simulation-based performance studies. Performance of several caching schemes are evaluated and compared with those of the proposed scheme. Our empirical results indicate GD-multi performs well despite employing a generalized caching policy.

Learning other agents' preferences in multiagent negotiation

In multiagent systems, an agent does not usually have complete information about the preferences and decision making processes of other agents. This might prevent the agents from making coordinated choices, purely due to their ignorance of what others want. This paper describes the integration of a learning module into a communication-intensive negotiating agent architecture. The learning module gives the agents the ability to learn about other agents' preferences via past interactions. Over time, the agents can incrementally update their models of other agents' preferences and use them to make better coordinated decisions. Combining both communication and learning, as two complement knowledge acquisition methods, helps to reduce the amount of communication needed on average, and is justified in situations where communication is computationally costly or simply not desirable (e.g. to preserve the individual privacy).

Supervised subspace learning with multi-class Lagrangian SVM on the Grassmann manifold

Learning robust subspaces to maximize class discrimination is challenging, and most current works consider a weak connection between dimensionality reduction and classifier design. We propose an alternate framework wherein these two steps are combined in a joint formulation to exploit the direct connection between dimensionality reduction and classification. Specifically, we learn an optimal subspace on the Grassmann manifold jointly minimizing the classification error of an SVM classifier. We minimize the regularized empirical risk over both the hypothesis space of functions that underlies this new generalized multi-class Lagrangian SVM and the Grassmann manifold such that a linear projection is to be found. We propose an iterative algorithm to meet the dual goal of optimizing both the classifier and projection. Extensive numerical studies on challenging datasets show robust performance of the proposed scheme over other alternatives in contexts wherein limited training data is used, verifying the advantage of the joint formulation.