James Alfred Walker

James Alfred Walker
The University of York · Department of Computer Science

Doctor of Philosophy

About

95
Publications
16,895
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914
Citations

Publications

Publications (95)
Article
Full-text available
Every minute, 500 h of footage is uploaded to Youtube.com, and ∼1900 h of footage is livestreamed on Twitch.tv. It can therefore be challenging for viewers to find the content they are most likely to enjoy. Highlight videos can entertain users who did not watch a broadcast, e.g. due to a lack of awareness, availability, or willingness. Furthermore,...
Article
Conversational Artificial Intelligence (CAI) systems and Intelligent Personal Assistants (IPA), such as Alexa, Cortana, Google Home and Siri are becoming ubiquitous in our lives, including those of children, the implications of which is receiving increased attention, specifically with respect to the effects of these systems on children’s cognitive,...
Preprint
Full-text available
Conversational Artificial Intelligence (CAI) systems and Intelligent Personal Assistants (IPA), such as Alexa, Cortana, Google Home and Siri are becoming ubiquitous in our lives, including those of children, the implications of which is receiving increased attention, specifically with respect to the effects of these systems on children's cognitive,...
Chapter
Indirect encoding is a promising area of research in machine learning/evolutionary computation, however, it is rarely able to achieve performance on par with state of the art directly encoded methods. One of the most important properties of indirect encoding is the ability to control exploration during learning by transforming random genotypic vari...
Preprint
Full-text available
One of the most important lessons from the success of deep learning is that learned representations tend to perform much better at any task compared to representations we design by hand. Yet evolution of evolvability algorithms, which aim to automatically learn good genetic representations, have received relatively little attention, perhaps because...
Article
The notion of self-play, albeit often cited in multiagent Reinforcement Learning as a process by which to train agent policies from scratch, has received little efforts to be taxonomized within a formal model. We present a formalized framework, with clearly defined assumptions, which encapsulates the meaning of self-play as abstracted from various...
Preprint
Full-text available
The drivers of compositionality in artificial languages that emerge when two (or more) agents play a non-visual referential game has been previously investigated using approaches based on the REINFORCE algorithm and the (Neural) Iterated Learning Model. Following the more recent introduction of the \textit{Straight-Through Gumbel-Softmax} (ST-GS) a...
Preprint
Full-text available
Natural languages are powerful tools wielded by human beings to communicate information and co-operate towards common goals. Their values lie in some main properties like compositionality, hierarchy and recurrent syntax, which computational linguists have been researching the emergence of in artificial languages induced by language games. Only rela...
Article
Full-text available
Decentralised gambling applications are a new way for people to gamble online. Decentralised gambling applications are distinguished from traditional online casinos in that players use cryptocurrency as a stake. Also, rather than being stored on a single centralised server, decentralised gambling applications are stored on a cryptocurrency’s blockc...
Article
Full-text available
The automated evaluation of creative products promises both good-and-scalable creativity assessments and new forms of visual analysis of whole corpora. Where creative works are not ‘born digital’, such automated evaluation requires fast and frugal ways of transforming them into data representations that can be meaningfully assessed with common crea...
Preprint
Full-text available
Throughout scientific history, overarching theoretical frameworks have allowed researchers to grow beyond personal intuitions and culturally biased theories. They allow to verify and replicate existing findings, and to link disconnected results. The notion of self-play, albeit often cited in multiagent Reinforcement Learning, has never been grounde...
Conference Paper
Full-text available
Automated game balancing has often focused on single-agent scenarios. In this paper we present a tool for balancing multi-player games during game design. Our approach requires a designer to construct an intuitive graphical representation of their meta-game target, representing the relative scores that high-level strategies (or decks, or character...
Preprint
Full-text available
Automated game balancing has often focused on single-agent scenarios. In this paper we present a tool for balancing multi-player games during game design. Our approach requires a designer to construct an intuitive graphical representation of their meta-game target, representing the relative scores that high-level strategies (or decks, or character...
Article
Full-text available
Automated game balancing has often focused on single-agent scenarios. In this paper we present a tool for balancing multi-player games during game design. Our approach requires a designer to construct an intuitive graphical representation of their meta-game target, representing the relative scores that high-level strategies (or decks, or character...
Article
Player clustering when applied to the field of video games has several potential applications. For example, the evaluation of the composition of a player base or the generation of AI agents with identified playing styles. These agents can then be used for either the testing of new game content or used directly to enhance a player’s gaming experienc...
Preprint
Full-text available
Decentralised gambling applications are a new way for individuals to engage in online gambling. Decentralised gambling applications are distinguished from traditional online casinos in that individuals use cryptocurrency as a stake. Furthermore, rather than being stored on a traditional server, decentralised gambling applications are stored on a cr...
Conference Paper
In computer graphics and virtual environment development, a large portion of time is spent creating assets - one of these being the terrain environment, which usually forms the basis of many large graphical worlds. The texturing of height maps is usually performed as a post-processing step - with software requiring access to the height and gradient...
Conference Paper
Full-text available
Ethereum crypto-games are a booming and relatively unexplored area of the games industry. While there is no consensus definition yet, 'crypto-games' commonly denotes games that store tokens, e.g. in-game items, on a distributed ledger atop a cryptocurrency network. This enables the trading of game items for cryptocurrency, which can then be exchang...
Preprint
Full-text available
Decentralised gambling can be described as a type of online gambling. This submission evidences the form and prevalence of decentralised gambling applications, and shows how this information can help address several of the committee’s questions. This document was prepared for, accepted, and published by, the House of Lords Select Committee on the S...
Conference Paper
Full-text available
Hyperinflation and price volatility in virtual economies has the potential to reduce player satisfaction and decrease developer revenue. This paper describes intuitive analytical methods for monitoring volatility and inflation in virtual economies, with worked examples on the increasingly popular multiplayer game Old School Runescape. Analytical me...
Presentation
Full-text available
This presentation covers some of the key ideas in the corresponding paper, including interpreting bivariate plots of market data, creating virtual economic indexes, and applying statistical tests to indexes (and returns). This presentation was given on Wednesday at IEEE COG 2019 under the 'Analytics and Player Modelling' track.
Presentation
Full-text available
Data driven gambling research has historically been limited by the availability of rich large scale data sets, which have seldom been published for replication studies. In contrast, new gambling services built using distributed ledger technology, as underpins cryptocurrencies, allow inspection of gambling activity through these services at the indi...
Poster
Full-text available
This poster describes in plain terms the key findings from the talk given at the Current Advances in Gambling Research (CAGR) conference in 2019. This poster exists purely digitally and was not formally presented, instead acting to supplement the content of the presentation and corresponding pre-print, which described decentralised gambling and the...
Conference Paper
Full-text available
Throughout scientific history, overarching theoretical frameworks have allowed researchers to grow beyond personal intuitions and culturally biased theories. They allow to verify and replicate existing findings, and to link disconnected results. The notion of self-play, albeit often cited in multiagent Reinforcement Learning, has never been grounde...
Preprint
Full-text available
This paper describes the York Combined Transaction Set (YCTS), which offers a single consolidated list of publicly available gambling related transactions derived from the Ethereum blockchain. This data includes over 1.4M individual transactions across 17,000+ unique addresses, which represent spending on decentralised gambling smart contracts. The...
Article
Full-text available
Circuit clustering algorithms fit synthesised circuits into FPGA configurable logic blocks (CLBs) efficiently. This fundamental process in FPGA CAD flow directly impacts both effort required and performance achievable in subsequent place-and-route processes. Circuit clustering is limited by hardware constraints of specific target architectures. Hen...
Preprint
Full-text available
Video game streaming provides the viewer with a rich set of audio-visual data, conveying information both with regards to the game itself, through game footage and audio, as well as the streamer's emotional state and behaviour via webcam footage and audio. Analysing player behaviour and discovering correlations with game context is crucial for mode...
Preprint
Full-text available
Heightmap generation is currently a tedious topic with the majority of generation using Perlin noise which forms a reliable, but sometimes repetitive output. In this paper, a method of generating height maps from real-world digital elevation data taken from specific regions of the planet is proposed. Raw elevation data sourced from NASA's SRTM (30m...
Preprint
Full-text available
Esports have become major international sports with hundreds of millions of spectators. Esports games generate massive amounts of telemetry data. Using these to predict the outcome of esports matches has received considerable attention, but micro-predictions, which seek to predict events inside a match, is as yet unknown territory. Micro-prediction...
Preprint
Full-text available
Hyperinflation and price volatility in virtual economies has the potential to reduce player satisfaction and decrease developer revenue. This paper describes intuitive analytical methods for monitoring volatility and inflation in virtual economies, with worked examples on the increasingly popular multiplayer game Old School Runescape. Analytical me...
Chapter
Measuring wave heights has traditionally been associated with physical buoy tools that aim to measure and average multiple wave heights over a period of time. With our method, we demonstrate a process of utilizing large-scale satellite images to classify a wave height with a continuous regressive output using a corresponding input for close shore s...
Article
We propose a memetic approach to find bottlenecks in complex networks based on searching for a graph partitioning with minimum conductance. Finding the optimum of this problem, also known in statistical mechanics as the Cheeger constant, is one of the most interesting NP-hard network optimisation problems. The existence of low conductance minima in...
Chapter
This chapter describes the use of biologically inspired Evolutionary Algorithms (EAs) to create designs for implementation on a reconfigurable logic device. Previous work on Evolvable Hardware (EHW) is discussed with a focus on timing problems for digital circuits. An EA is developed that describes the circuit using a Hardware Description Language...
Article
Full-text available
A novel hierarchical fault-tolerance methodology for reconfigurable devices is presented. A bespoke multi-reconfigurable FPGA architecture, the programmable analogue and digital array (PAnDA), is introduced allowing fine-grained reconfiguration beyond any other FPGA architecture currently in existence. Fault blind circuit repair strategies, which r...
Conference Paper
Semiconductor devices have rapidly improved in performance and function density over the past 25 years enabled by the continuous shrinking of technology feature sizes. Fabricating transistors that small, even with advanced processes, results in structural irregularities at the atomic scale, which affect device characteristics in a random manner. To...
Article
Full-text available
In this study, the authors present a design optimisation case study of D-type flip-flop timing characteristics that are degraded as a result of intrinsic stochastic variability in a 25 nm technology process. What makes this work unique is that the design is mapped onto a multi-reconfigurable architecture, which is, like a field programmable gate ar...
Article
The speed and function density of field-programmable gate arrays (FPGAs) are increasing as transistor sizes shrink to the nano-scale. As transistors reduce in size and approach the atomic scale, the presence or absence of single doping atoms and structural irregularities are likely to affect the behaviour of the device in a random manner (Papanikol...
Conference Paper
Full-text available
The modeling and simulation of semiconductor devices is a difficult and computationally intensive task. However the expense of fabrication and testing means that accurate modeling and simulation are crucial to the continued progress of the industry. To create these models and then perform the simulations requires parameters from accurate physical m...
Conference Paper
This paper presents the concept of hierarchical reconfiguration strategies that can be applied to a circuit on a reconfigurable architecture to change the implementation without changing the functionality, and their use to overcome faults in a source agnostic way. The Programmable Analogue and Digital Array (PAnDA) is a novel FPGA-like reconfigurab...
Article
Full-text available
Field programmable gate arrays (FPGAs) are widely used in applications where online reconfigurable signal processing is required. Speed and function density of FPGAs are increasing as transistor sizes shrink to the nanoscale. As these transistors reduce in size intrinsic variability becomes more of a problem and to reliably create electronic design...
Conference Paper
This paper explores the potential for transistor level fault tolerance on a new Programmable Analogue and Digital Array (PAnDA) architecture1. In particular, this architecture features Combinatorial Configurable Analogue Blocks (CCABs) that can implement a number of combinatorial functions similar to FPGAs. In addition, PAnDA allows one to reconfig...
Conference Paper
Full-text available
Field programmable gate arrays (FPGAs) are widely used in applications where on-line reconfigurable signal processing is required. Speed and function density of FPGAs are increasing as transistor sizes shrink to the nano-scale. As these transistors reduce in size, intrinsic variability becomes more of a problem, as every physical instance of a desi...
Conference Paper
Full-text available
The Programmable Analogue and Digital Array (PAnDA) is a novel reconfigurable architecture, which allows variability aware design and rapid prototyping of digital systems. Exploiting the configuration options of the architecture allows the post-fabrication correction and optimisation of circuits directly in hardware using bio-inspired techniques. I...
Article
Transport triggered architectures are used for implementing bio-inspired systems due to their simplicity, modularity and fault-tolerance. However, producing efficient, optimised machine code for such architectures is extremely difficult, since computational complexity has moved from the hardware-level to the software-level. Presented is the applica...
Book
This book constitutes the refereed proceedings of the 9th International Conference on Information in Cells and Tissues, IPCAT 2012, held in Cambridge, UK, in March/April 2012. The 13 revised full papers presented together with 26 extended abstracts were carefully reviewed and selected from numerous submissions. The papers cover a wide range of topi...
Article
Field programmable gate arrays (FPGAs) are widely used in applications where on-line reconfigurable signal processing is required. Speed and function density of FPGAs are increasing when shrinking transistor sizes to the nano-scale. Unfortunately, in order to reliably create electronic designs according to specification time-consuming statistical s...
Chapter
Cartesian Genetic Programming (CGP) is now attracting considerable recognition as an evolutionary algorithm that not only delivers high performance, but one that has a representation that is flexible and easy to adapt to a range of applications. Problems based in medicine stand to benefit greatly due their diverse and highly non-linear nature, whic...
Article
Evolvable Hardware has been a discipline for over 15 years. Its application has ranged from simple circuit design to antenna design. However, research in the field has often been criticised for not addressing real world problems. Intrinsic variability has been recognised as one of the major challenges facing the semiconductor industry. This paper d...
Conference Paper
In the past decades, a number of genetic programming techniques have been developed to evolve machine instructions. However, these approaches typically suffer from a lack of scalability that seriously impairs their applicability to real-world scenarios. In this paper, a novel self-scaling instruction generation method is introduced, which tries to...
Chapter
Full-text available
From the outset, the field of Evolvable Hardware has proved its potential for evolution of innovative circuits and hardware adaptation and repair. CGP has been utilized in both tasks of hardware evolution as well as adaptation. This chapter illustrates some typical applications of CGP, comprising gate-level evolution of ordinary and polymorphic cir...