JHD has worked in Mathematics and Computer Science since before the fields differentiated. His main field is computer algebra, but he also works in cryptography and computational logic, satsifiability modulo theories.
2020 22nd International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC)
This paper is part of our ongoing research and collaboration on understanding the relations betwe... more This paper is part of our ongoing research and collaboration on understanding the relations between CAD algorithms, equational constraints and curtains. Our previous work manages to circumvent the curtain problem in the single equational constraint by taking advantage of the Lex-least valuation (even in the presence of curtains). That method however fails to take full advantage of multiple equational constraints. In this paper we provide further clarification of McCallum's work to validate the use of restricted projection operator at 2 levels. We also discuss the close relationship between order invariant and lex-least invariant CAD's.
Proceedings of the 3rd Conference on Computing Education Practice, 2019
This paper describes a course that has been running for over nine years, teaching Programming to ... more This paper describes a course that has been running for over nine years, teaching Programming to large number of Mathematics students. The distinctive features of it include the fact that it was designed as part of a wholesale curriculum review (rather than being a pre-packaged course), that its design took into account the nature of the syllabus and what else the students would be using programming for, both in the rest of their course and beyond, and that the course is more than "just" a programming course.
The sudden change of moving the majority of teaching online at Universities due to the global Cov... more The sudden change of moving the majority of teaching online at Universities due to the global Covid-19 pandemic has caused an increased amount of workload for academics. One of the contributing factors is answering a high volume of queries coming from students. As these queries are not limited to the synchronous time frame of a lecture, there is a high chance of many of them being related or even equivalent. One way to deal with this problem is to cluster these questions depending on their topic. In our previous work, we aimed to find an improved method of clustering that would give us a high efficiency, using a recurring LDA model. Our data set contained questions posted online from a Computer Science course at the University of Bath. A significant number of these questions contained code excerpts, which we found caused a problem in clustering, as certain terms were being considered as common words in the English language and not being recognised as specific code terms. To address ...
There has been an increasingly popular trend in Universities for curriculum transformation to mak... more There has been an increasingly popular trend in Universities for curriculum transformation to make teaching more interactive and suitable for online courses. An increase in the popularity of online courses would result in an increase in the number of course-related queries for academics. This, coupled with the fact that if lectures were delivered in a video on demand format, there would be no fixed time where the majority of students could ask questions. When questions are asked in a lecture there is a negligible chance of having similar questions repeatedly, but asynchronously this is more likely. In order to reduce the time spent on answering each individual question, clustering them is an ideal choice. There are different unsupervised models fit for text clustering, of which the Latent Dirichlet Allocation model is the most commonly used. We use the Hierarchical Dirichlet Process to determine an optimal topic number input for our LDA model runs. Due to the probabilistic nature of...
This report is based on the discussions and presentations that took place at the Workshop on Sust... more This report is based on the discussions and presentations that took place at the Workshop on Sustainable Software Sustainability (www.software.ac.uk/wosss19) in April 2019 (WOSSS19). It captures the state of the art for a range of Software Sustainability themes that were brought up by the organisers and attendees of the workshop.
Professional body accreditation must better communicate its value to higher education institution... more Professional body accreditation must better communicate its value to higher education institutions, industry and society as a whole. Tom Crick, James H. Davenport, Paul Hanna, Alastair Irons, Sally Pearce and Tom Prickett explore the value of - and future enhancements to - BCS accreditation.
We consider two methods for CADs, one due to McCallum and one due to Lazard. The former uses orde... more We consider two methods for CADs, one due to McCallum and one due to Lazard. The former uses order invariant CADs and has been modified, by McCallum himself, so as to take advantage of equational constraints. Lazard’s method uses lex-least invariant CADs and is in general faster. In this paper, we start to modify Lazard’s method so as to exploit equational constraints. Our algorithm takes in a lex-least invariant CAD of Rn−1 as input and outputs a sign invariant CAD of a subvariety of R: consequently, it cannot be used recursively, but only for xn, the first variable to be projected. In the further steps of the projection phase, we use Lazard’s original projection operator. Nonetheless, reducing the output in the first step has a domino effect throughout the remaining steps, which significantly reduces the complexity. The long-term goal is to find a general projection operator that takes advantage of the equality constraint and can be used recursively, and this operator gives an imp...
Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of ... more Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of a new research project, whose necessity arises both from the computational imperative of applying algebra to CAD and the difficulties of applying existing systems to ...
The seminal survey by Barton and ffitch [1] describes various classic problems in computer algebr... more The seminal survey by Barton and ffitch [1] describes various classic problems in computer algebra. Here we look at these problems from the perspectives of both the hardware and software of 2009.
2020 22nd International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC)
This paper is part of our ongoing research and collaboration on understanding the relations betwe... more This paper is part of our ongoing research and collaboration on understanding the relations between CAD algorithms, equational constraints and curtains. Our previous work manages to circumvent the curtain problem in the single equational constraint by taking advantage of the Lex-least valuation (even in the presence of curtains). That method however fails to take full advantage of multiple equational constraints. In this paper we provide further clarification of McCallum's work to validate the use of restricted projection operator at 2 levels. We also discuss the close relationship between order invariant and lex-least invariant CAD's.
Proceedings of the 3rd Conference on Computing Education Practice, 2019
This paper describes a course that has been running for over nine years, teaching Programming to ... more This paper describes a course that has been running for over nine years, teaching Programming to large number of Mathematics students. The distinctive features of it include the fact that it was designed as part of a wholesale curriculum review (rather than being a pre-packaged course), that its design took into account the nature of the syllabus and what else the students would be using programming for, both in the rest of their course and beyond, and that the course is more than "just" a programming course.
The sudden change of moving the majority of teaching online at Universities due to the global Cov... more The sudden change of moving the majority of teaching online at Universities due to the global Covid-19 pandemic has caused an increased amount of workload for academics. One of the contributing factors is answering a high volume of queries coming from students. As these queries are not limited to the synchronous time frame of a lecture, there is a high chance of many of them being related or even equivalent. One way to deal with this problem is to cluster these questions depending on their topic. In our previous work, we aimed to find an improved method of clustering that would give us a high efficiency, using a recurring LDA model. Our data set contained questions posted online from a Computer Science course at the University of Bath. A significant number of these questions contained code excerpts, which we found caused a problem in clustering, as certain terms were being considered as common words in the English language and not being recognised as specific code terms. To address ...
There has been an increasingly popular trend in Universities for curriculum transformation to mak... more There has been an increasingly popular trend in Universities for curriculum transformation to make teaching more interactive and suitable for online courses. An increase in the popularity of online courses would result in an increase in the number of course-related queries for academics. This, coupled with the fact that if lectures were delivered in a video on demand format, there would be no fixed time where the majority of students could ask questions. When questions are asked in a lecture there is a negligible chance of having similar questions repeatedly, but asynchronously this is more likely. In order to reduce the time spent on answering each individual question, clustering them is an ideal choice. There are different unsupervised models fit for text clustering, of which the Latent Dirichlet Allocation model is the most commonly used. We use the Hierarchical Dirichlet Process to determine an optimal topic number input for our LDA model runs. Due to the probabilistic nature of...
This report is based on the discussions and presentations that took place at the Workshop on Sust... more This report is based on the discussions and presentations that took place at the Workshop on Sustainable Software Sustainability (www.software.ac.uk/wosss19) in April 2019 (WOSSS19). It captures the state of the art for a range of Software Sustainability themes that were brought up by the organisers and attendees of the workshop.
Professional body accreditation must better communicate its value to higher education institution... more Professional body accreditation must better communicate its value to higher education institutions, industry and society as a whole. Tom Crick, James H. Davenport, Paul Hanna, Alastair Irons, Sally Pearce and Tom Prickett explore the value of - and future enhancements to - BCS accreditation.
We consider two methods for CADs, one due to McCallum and one due to Lazard. The former uses orde... more We consider two methods for CADs, one due to McCallum and one due to Lazard. The former uses order invariant CADs and has been modified, by McCallum himself, so as to take advantage of equational constraints. Lazard’s method uses lex-least invariant CADs and is in general faster. In this paper, we start to modify Lazard’s method so as to exploit equational constraints. Our algorithm takes in a lex-least invariant CAD of Rn−1 as input and outputs a sign invariant CAD of a subvariety of R: consequently, it cannot be used recursively, but only for xn, the first variable to be projected. In the further steps of the projection phase, we use Lazard’s original projection operator. Nonetheless, reducing the output in the first step has a domino effect throughout the remaining steps, which significantly reduces the complexity. The long-term goal is to find a general projection operator that takes advantage of the equality constraint and can be used recursively, and this operator gives an imp...
Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of ... more Work is currenty progressing, using REDUCE for prototyping. This paper has outlined the scope of a new research project, whose necessity arises both from the computational imperative of applying algebra to CAD and the difficulties of applying existing systems to ...
The seminal survey by Barton and ffitch [1] describes various classic problems in computer algebr... more The seminal survey by Barton and ffitch [1] describes various classic problems in computer algebra. Here we look at these problems from the perspectives of both the hardware and software of 2009.
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