Best Response Games on Regular Graphs

With the growth of the internet it is becoming increasingly important to understand how the behaviour of players is affected by the topology of the network interconnecting them. Many models which involve networks of interacting players have been proposed and best response games are amongst the simplest. In best response games each vertex simultaneously updates to employ the best response to their current surroundings. We concentrate upon trying to understand the dynamics of best response games on regular graphs with many strategies. When more than two strategies are present highly complex dynamics can ensue. We focus upon trying to understand exactly how best response games on regular graphs sample from the space of possible cellular automata. To understand this issue we investigate convex divisions in high dimensional space and we prove that almost every division of $k-1$ dimensional space into $k$ convex regions includes a single point where all regions meet. We then find connections between the convex geometry of best response games and the theory of alternating circuits on graphs. Exploiting these unexpected connections allows us to gain an interesting answer to our question of when cellular automata are best response games

Complex Networks from Simple Rewrite Systems

Complex networks are all around us, and they can be generated by simple mechanisms. Understanding what kinds of networks can be produced by following simple rules is therefore of great importance. We investigate this issue by studying the dynamics of extremely simple systems where are `writer' moves around a network, and modifies it in a way that depends upon the writer's surroundings. Each vertex in the network has three edges incident upon it, which are colored red, blue and green. This edge coloring is done to provide a way for the writer to orient its movement. We explore the dynamics of a space of 3888 of these `colored trinet automata' systems. We find a large variety of behaviour, ranging from the very simple to the very complex. We also discover simple rules that generate forms which are remarkably similar to a wide range of natural objects. We study our systems using simulations (with appropriate visualization techniques) and analyze selected rules mathematically. We arrive at an empirical classification scheme which reveals a lot about the kinds of dynamics and networks that can be generated by these systems

Distributed Time-Sensitive Task Selection in Mobile Crowdsensing

With the rich set of embedded sensors installed in smartphones and the large number of mobile users, we witness the emergence of many innovative commercial mobile crowdsensing applications that combine the power of mobile technology with crowdsourcing to deliver time-sensitive and location-dependent information to their customers. Motivated by these real-world applications, we consider the task selection problem for heterogeneous users with different initial locations, movement costs, movement speeds, and reputation levels. Computing the social surplus maximization task allocation turns out to be an NP-hard problem. Hence we focus on the distributed case, and propose an asynchronous and distributed task selection (ADTS) algorithm to help the users plan their task selections on their own. We prove the convergence of the algorithm, and further characterize the computation time for users' updates in the algorithm. Simulation results suggest that the ADTS scheme achieves the highest Jain's fairness index and coverage comparing with several benchmark algorithms, while yielding similar user payoff to a greedy centralized benchmark. Finally, we illustrate how mobile users coordinate under the ADTS scheme based on some practical movement time data derived from Google Maps

Development and validation of a spectro-temporal processing test for cochlear-implant listeners.

Psychophysical tests of spectro-temporal resolution may aid the evaluation of methods for improving hearing by cochlear implant (CI) listeners. Here the STRIPES (Spectro-Temporal Ripple for Investigating Processor EffectivenesS) test is described and validated. Like speech, the test requires both spectral and temporal processing to perform well. Listeners discriminate between complexes of sine sweeps which increase or decrease in frequency; difficulty is controlled by changing the stimulus spectro-temporal density. Care was taken to minimize extraneous cues, forcing listeners to perform the task only on the direction of the sweeps. Vocoder simulations with normal hearing listeners showed that the STRIPES test was sensitive to the number of channels and temporal information fidelity. An evaluation with CI listeners compared a standard processing strategy with one having very wide filters, thereby spectrally blurring the stimulus. Psychometric functions were monotonic for both strategies and five of six participants performed better with the standard strategy. An adaptive procedure revealed significant differences, all in favour of the standard strategy, at the individual listener level for six of eight CI listeners. Subsequent measures validated a faster version of the test, and showed that STRIPES could be performed by recently implanted listeners having no experience of psychophysical testing

Using high-resolution digital photography and micro-CT scanning to investigate Deathwatch Beetle damage to an historic timber from HMS Victory

Wood-boring insects such as the deathwatch beetle can cause significant damage to historical artefacts and timbers, but the extent of internal damage (and tunnelling activity in general) can be difficult to understand and quantify without the use of destructive sampling techniques. This study explored the potential of high-resolution photography and micro-computed tomography (micro-CT) to investigate beetle activity and inform on the extent of internal damage to a timber from HMS Victory. Micro-CT imaging has allowed the visualisation of deathwatch beetle activity within the timber, revealing differences in tunnelling behaviour preferences for adult and larval forms. Digital techniques were developed to determine the surface area of flight holes on some wooden blocks but were less successful for those blocks where the external surfaces were darkened with age. It was not possible to accurately determine the internal volumes of beetle tunnels within blocks of timber due to the presence of frass, which was found to be virtually indistinguishable digitally from the wood matrix

Transfer of training in an academic leadership development program for program coordinators

The higher education sector has increasingly begun to pay more attention to academic leadership. This qualitative study explores how such an investment in a 20-week leadership development program influenced the behaviour of 10 academic staff in the role of program coordinator 6 to 12 months following participation in the program. Otherwise known as program directors or department chairs, academic staff in this role are responsible for coordinating and leading degree courses or programs. Leadership learning and changes in the behaviour of program coordinators was evident, particularly in regard to building influence, communicating more effectively and managing upwards. Improved confidence in their ability to perform the role was a lasting outcome and the use of peer learning and coaching was an important part of the success of the intervention. However, workload factors, succession planning and orientation were seen to be factors that impact on leadership development in this role. The findings suggest that participation in well designed academic leadership programs can result in a lasting transfer of training for program coordinators