2020 |
Graham, David I; Craven, Matthew J An Exact Algorithm for Small-Cardinality Constrained Portfolio Optimisation Journal Article Journal of the Operational Research Society, 2020. @article{digmjc2, title = {An Exact Algorithm for Small-Cardinality Constrained Portfolio Optimisation}, author = {David I. Graham and Matthew J. Craven}, doi = {10.1080/01605682.2020.1718019}, year = {2020}, date = {2020-02-13}, journal = {Journal of the Operational Research Society}, abstract = {Real-world portfolio optimisation problems are often NP-hard, their efficient frontiers (EFs) in practice being calculated by randomised algorithms. In this work, a deterministic method of decomposition of EFs into a short sequence of sub-EFs is presented. These sub-EFs may be calculated by a quadratic programming algorithm, the collection of such sub-EFs then being subjected to a sifting process to produce the full EF. Full EFs of portfolio optimisation problems with small cardinality constraints are computed to a high resolution, providing a fast and practical alternative to randomised algorithms. The method may also be used with other practical classes of portfolio problems, complete with differing measures of risk. Finally, it is shown that the identified sub-EFs correspond closely to local optima of the objective function of a case study evolutionary algorithm.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Real-world portfolio optimisation problems are often NP-hard, their efficient frontiers (EFs) in practice being calculated by randomised algorithms. In this work, a deterministic method of decomposition of EFs into a short sequence of sub-EFs is presented. These sub-EFs may be calculated by a quadratic programming algorithm, the collection of such sub-EFs then being subjected to a sifting process to produce the full EF. Full EFs of portfolio optimisation problems with small cardinality constraints are computed to a high resolution, providing a fast and practical alternative to randomised algorithms. The method may also be used with other practical classes of portfolio problems, complete with differing measures of risk. Finally, it is shown that the identified sub-EFs correspond closely to local optima of the objective function of a case study evolutionary algorithm. |
Dyke, Phil; Searl, John; Craven, Matthew J; Wei, Yinghui Modern Engineering Mathematics Book Forthcoming Pearson, Forthcoming. @book{dykeetal2020, title = {Modern Engineering Mathematics}, author = {Phil Dyke and John Searl and Matthew J. Craven and Yinghui Wei}, year = {2020}, date = {2020-00-00}, publisher = {Pearson}, keywords = {}, pubstate = {forthcoming}, tppubtype = {book} } |
2019 |
Walker, David J; Craven, Matthew J Identifying Good Algorithm Parameters in Evolutionary Multi- and Many-Objective Optimisation: A Visualisation Approach Journal Article Applied Soft Computing, pp. 105902, 2019. @article{djw-mjc-3, title = {Identifying Good Algorithm Parameters in Evolutionary Multi- and Many-Objective Optimisation: A Visualisation Approach}, author = {David J. Walker and Matthew J. Craven}, doi = {10.1016/j.asoc.2019.105902}, year = {2019}, date = {2019-11-28}, journal = {Applied Soft Computing}, pages = {105902}, abstract = {Evolutionary algorithms are often highly dependent on the correct setting of their parameters, and benchmarking different parametrisations allows a user to identify which parameters offer the best performance on their given problem. Visualisation offers a way of presenting the results of such benchmarking so that a non-expert user can understand how their algorithm is performing. By examining the characteristics of their algorithm, such as convergence and diversity, the user can learn how effective their chosen algorithm parametrisation is. This paper presents a technique intended to offer this insight, by presenting the relative performance of a set of EAs optimising the same multi-objective problem in a simple visualisation. The visualisation characterises the behaviour of the algorithm in terms of known performance indicators drawn from the literature, and is capable of visualising the optimisation of many-objective problems also. The method is demonstrated with benchmark test problems from the popular DTLZ and CEC 2009 problem suites, optimising them with different parametrisations of both NSGA-II and NSGA-III, and it is shown that known characteristics of optimisers solving these problems can be observed in the visualisations resulting.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Evolutionary algorithms are often highly dependent on the correct setting of their parameters, and benchmarking different parametrisations allows a user to identify which parameters offer the best performance on their given problem. Visualisation offers a way of presenting the results of such benchmarking so that a non-expert user can understand how their algorithm is performing. By examining the characteristics of their algorithm, such as convergence and diversity, the user can learn how effective their chosen algorithm parametrisation is. This paper presents a technique intended to offer this insight, by presenting the relative performance of a set of EAs optimising the same multi-objective problem in a simple visualisation. The visualisation characterises the behaviour of the algorithm in terms of known performance indicators drawn from the literature, and is capable of visualising the optimisation of many-objective problems also. The method is demonstrated with benchmark test problems from the popular DTLZ and CEC 2009 problem suites, optimising them with different parametrisations of both NSGA-II and NSGA-III, and it is shown that known characteristics of optimisers solving these problems can be observed in the visualisations resulting. |
Alotaibi, Tahani S; Craven, Matthew J Efficient Frontiers in Portfolio Optimisation with Minimum Proportion Constraints Inproceedings Proceedings of the Companion Publication of the 2019 Annual Conference on Genetic and Evolutionary Computation, pp. 358-359, 2019. @inproceedings{tsa-mjc-1, title = {Efficient Frontiers in Portfolio Optimisation with Minimum Proportion Constraints}, author = {Tahani S. Alotaibi and Matthew J. Craven}, doi = {10.1145/3319619.3321900}, year = {2019}, date = {2019-07-31}, booktitle = {Proceedings of the Companion Publication of the 2019 Annual Conference on Genetic and Evolutionary Computation}, pages = {358-359}, abstract = {This work chronicles research into the solution of portfolio problems with metaheuristic solvers. In particular, a genetic algorithm for solving the cardinality constrained portfolio optimisation problem with minimum asset proportions is presented and tested on the datasets of [1]. These datasets form benchmark instances used to test portfolio optimisers and are based upon indices ranging from 31 to 225 assets. The results of the GA are indicatively compared to solutions of [2] for a variety of minimum proportions, suggesting that solutions exhibit certain clustering characteristics for higher proportions. Further work is also discussed. This research is based upon the first part of the ongoing PhD thesis of the first author. }, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } This work chronicles research into the solution of portfolio problems with metaheuristic solvers. In particular, a genetic algorithm for solving the cardinality constrained portfolio optimisation problem with minimum asset proportions is presented and tested on the datasets of [1]. These datasets form benchmark instances used to test portfolio optimisers and are based upon indices ranging from 31 to 225 assets. The results of the GA are indicatively compared to solutions of [2] for a variety of minimum proportions, suggesting that solutions exhibit certain clustering characteristics for higher proportions. Further work is also discussed. This research is based upon the first part of the ongoing PhD thesis of the first author. |
Brakhage, K H; Niemeyer, A C; Plesken, W; Robertz, D; Strzelczyk, A The icosahedra of edge length 1 Journal Article Journal of Algebra, 545 , pp. 4–26, 2019. @article{BrakhageNiemeyerPleskenRobertzStrzelczyk, title = {The icosahedra of edge length 1}, author = {Brakhage, K. H. and Niemeyer, A. C. and Plesken, W. and Robertz, D. and Strzelczyk, A.}, doi = {doi:10.1016/j.jalgebra.2019.04.028}, year = {2019}, date = {2019-05-14}, journal = {Journal of Algebra}, volume = {545}, pages = {4--26}, abstract = {Retaining the combinatorial Euclidean structure of a regular icosahedron, namely the 20 equiangular (planar) triangles, the 30 edges of length 1, and the 12 different vertices together with the incidence structure, we investigate variations of the regular icosahedron admitting self-intersections of faces. We determine all rigid equivalence classes of these icosahedra with non-trivial automorphism group and find one curve of flexible icosahedra. Visualisations and explicit data for this paper are available under http://algebra.data.rwth-aachen. de/Icosahedra/visualplusdata.html.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Retaining the combinatorial Euclidean structure of a regular icosahedron, namely the 20 equiangular (planar) triangles, the 30 edges of length 1, and the 12 different vertices together with the incidence structure, we investigate variations of the regular icosahedron admitting self-intersections of faces. We determine all rigid equivalence classes of these icosahedra with non-trivial automorphism group and find one curve of flexible icosahedra. Visualisations and explicit data for this paper are available under http://algebra.data.rwth-aachen. de/Icosahedra/visualplusdata.html. |
Stuhlmeier, Raphael; Stiassnie, Michael Nonlinear dispersion for ocean surface waves Journal Article Journal of Fluid Mechanics, 859 , pp. 49–58, 2019. @article{stuhlmeier2019nonlinear, title = {Nonlinear dispersion for ocean surface waves}, author = {Raphael Stuhlmeier and Michael Stiassnie}, year = {2019}, date = {2019-01-01}, journal = {Journal of Fluid Mechanics}, volume = {859}, pages = {49--58}, publisher = {Cambridge University Press}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Gerdt, V P; Robertz, D Algorithmic Approach to Strong Consistency Analysis of Finite Difference Approximations to PDE Systems Inproceedings Proceedings of the 2019 International Symposium on Symbolic and Algebraic Computation, 15-18 July 2019, Beihang University, Beijing, China, pp. 163–170, 2019. @inproceedings{GerdtRobertz6, title = {Algorithmic Approach to Strong Consistency Analysis of Finite Difference Approximations to PDE Systems}, author = {Gerdt, V. P. and Robertz, D.}, year = {2019}, date = {2019-01-01}, booktitle = {Proceedings of the 2019 International Symposium on Symbolic and Algebraic Computation, 15-18 July 2019, Beihang University, Beijing, China}, pages = {163--170}, abstract = {For a wide class of polynomially nonlinear systems of partial differential equations we suggest an algorithmic approach to the s(trong)-consistency analysis of their finite difference approximations on Cartesian grids. First we apply the differential Thomas decomposition to the input system, resulting in a partition of the solution set. We consider the output simple subsystem that contains a solution of interest. Then, for this subsystem, we suggest an algorithm for verification of s-consistency for its finite difference approximation. For this purpose we develop a difference analogue of the differential Thomas decomposition, both of which jointly allow to verify the s-consistency of the approximation. As an application of our approach, we show how to produce s-consistent difference approximations to the incompressible Navier-Stokes equations including the pressure Poisson equation.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } For a wide class of polynomially nonlinear systems of partial differential equations we suggest an algorithmic approach to the s(trong)-consistency analysis of their finite difference approximations on Cartesian grids. First we apply the differential Thomas decomposition to the input system, resulting in a partition of the solution set. We consider the output simple subsystem that contains a solution of interest. Then, for this subsystem, we suggest an algorithm for verification of s-consistency for its finite difference approximation. For this purpose we develop a difference analogue of the differential Thomas decomposition, both of which jointly allow to verify the s-consistency of the approximation. As an application of our approach, we show how to produce s-consistent difference approximations to the incompressible Navier-Stokes equations including the pressure Poisson equation. |
2018 |
Craven, Matthew J; Sharp, Jenny "The Mathematics Problem": A Plymouth Foundation Year Case Study Journal Article J. Foundation Year Network, 1 , pp. 23-35, 2018. @article{craven-sharp-2018, title = {"The Mathematics Problem": A Plymouth Foundation Year Case Study}, author = {Matthew J. Craven and Jenny Sharp}, editor = {Peter Watts et al.}, url = {https://jfyn.co.uk/index.php/ukfyn/article/view/17}, year = {2018}, date = {2018-12-21}, journal = {J. Foundation Year Network}, volume = {1}, pages = {23-35}, abstract = {Research indicates the transition from school mathematics to university-level STEM courses is often problematic, leading to issues with student satisfaction and retention (the “Mathematics Problem”). An increasing number of HEIs are establishing foundation years in an effort to ameliorate this problem. Undergraduate Mathematics cohorts at Plymouth often contain a sizeable number of ex-foundation year students, meaning that efforts to enhance student foundation year experience are vital to student satisfaction, retention and further recruitment. This paper is a report mid-way through a two-year project to examine a partially-flipped learning approach to improve foundation year retention and mathematical knowledge of those progressing to undergraduate study. A preliminary evaluation of this approach is given by using student voice data obtained through focus groups and surveys, and reflections of staff are examined. This paper is an expansion of the work presented at the Foundation Year Network Annual Conference, 2018, the overarching research question being: “Does the Foundation Year provide an enhanced transition to Mathematics degrees compared with the traditional A-level route?”.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Research indicates the transition from school mathematics to university-level STEM courses is often problematic, leading to issues with student satisfaction and retention (the “Mathematics Problem”). An increasing number of HEIs are establishing foundation years in an effort to ameliorate this problem. Undergraduate Mathematics cohorts at Plymouth often contain a sizeable number of ex-foundation year students, meaning that efforts to enhance student foundation year experience are vital to student satisfaction, retention and further recruitment. This paper is a report mid-way through a two-year project to examine a partially-flipped learning approach to improve foundation year retention and mathematical knowledge of those progressing to undergraduate study. A preliminary evaluation of this approach is given by using student voice data obtained through focus groups and surveys, and reflections of staff are examined. This paper is an expansion of the work presented at the Foundation Year Network Annual Conference, 2018, the overarching research question being: “Does the Foundation Year provide an enhanced transition to Mathematics degrees compared with the traditional A-level route?”. |
Broomhead, Nathan T Thick subcategories of discrete derived categories Journal Article Advances in Mathematics, 336 , pp. 242 - 298, 2018, ISSN: 0001-8708. @article{BROOMHEAD2018242, title = {Thick subcategories of discrete derived categories}, author = {Nathan T Broomhead}, url = {http://www.sciencedirect.com/science/article/pii/S0001870818302871}, doi = {https://doi.org/10.1016/j.aim.2018.07.029}, issn = {0001-8708}, year = {2018}, date = {2018-10-01}, journal = {Advances in Mathematics}, volume = {336}, pages = {242 - 298}, abstract = {We classify the thick subcategories of discrete derived categories. To do this we introduce certain generating sets called ES-collections which correspond to configurations of non-crossing arcs on a geometric model. We show that every thick subcategory is generated by an ES-collection and we describe a version of mutation which acts transitively on the set of ES-collections generating a given thick subcategory.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We classify the thick subcategories of discrete derived categories. To do this we introduce certain generating sets called ES-collections which correspond to configurations of non-crossing arcs on a geometric model. We show that every thick subcategory is generated by an ES-collection and we describe a version of mutation which acts transitively on the set of ES-collections generating a given thick subcategory. |
Walker, David J; Craven, Matthew J Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems Inproceedings et al., La Loggia G (Ed.): Palermo, Italy, 2018. @inproceedings{walker2018visualisingb, title = {Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems}, author = {David J Walker and Matthew J Craven}, editor = {G. La Loggia et al.}, doi = {10.29007/j62b}, year = {2018}, date = {2018-09-01}, publisher = {Palermo, Italy}, abstract = {Multi-objective evolutionary algorithms (MOEAs) are well known for their ability to optimise the water distribution network design problem. However, their complex nature often restricts their use to algorithm experts. A method is proposed for visualising algorithm performance that will enable an engineer to compare different optimisers and select the best optimisation approach. Results show that the convergence and preservation of diversity can be shown in a simple visualisation that does not rely on in-depth MOEA experience.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Multi-objective evolutionary algorithms (MOEAs) are well known for their ability to optimise the water distribution network design problem. However, their complex nature often restricts their use to algorithm experts. A method is proposed for visualising algorithm performance that will enable an engineer to compare different optimisers and select the best optimisation approach. Results show that the convergence and preservation of diversity can be shown in a simple visualisation that does not rely on in-depth MOEA experience. |
Gerdt, V P; Lange-Hegermann, M; Robertz, D The MAPLE package TDDS for computing Thomas decompositions of systems of nonlinear PDEs Journal Article Computer Physics Communications, 234 , pp. 202–215, 2018. @article{GerdtLangeHegermannRobertzc, title = {The MAPLE package TDDS for computing Thomas decompositions of systems of nonlinear PDEs}, author = {Gerdt, V. P. and Lange-Hegermann, M. and Robertz, D.}, year = {2018}, date = {2018-08-10}, journal = {Computer Physics Communications}, volume = {234}, pages = {202--215}, abstract = {We present the Maple package TDDS (Thomas Decomposition of Differential Systems). Given a polynomially nonlinear differential system, which in addition to equations may contain inequations, this package computes a decomposition of it into a finite set of differentially triangular and algebraically simple subsystems whose subsets of equations are involutive. Usually the decomposed system is substantially easier to investigate and solve both analytically and numerically. The distinctive property of a Thomas decomposition is disjointness of the solution sets of the output subsystems. Thereby, a solution of a well-posed initial problem belongs to one and only one output subsystem. The Thomas decomposition is fully algorithmic. It allows to perform important elements of algebraic analysis of an input differential system such as: verifying consistency, i.e., the existence of solutions; detecting the arbitrariness in the general analytic solution; given an additional equation, checking whether this equation is satisfied by all common solutions of the input system; eliminating a part of dependent variables from the system if such elimination is possible; revealing hidden constraints on dependent variables, etc. Examples illustrating the use of the package are given. }, keywords = {}, pubstate = {published}, tppubtype = {article} } We present the Maple package TDDS (Thomas Decomposition of Differential Systems). Given a polynomially nonlinear differential system, which in addition to equations may contain inequations, this package computes a decomposition of it into a finite set of differentially triangular and algebraically simple subsystems whose subsets of equations are involutive. Usually the decomposed system is substantially easier to investigate and solve both analytically and numerically. The distinctive property of a Thomas decomposition is disjointness of the solution sets of the output subsystems. Thereby, a solution of a well-posed initial problem belongs to one and only one output subsystem. The Thomas decomposition is fully algorithmic. It allows to perform important elements of algebraic analysis of an input differential system such as: verifying consistency, i.e., the existence of solutions; detecting the arbitrariness in the general analytic solution; given an additional equation, checking whether this equation is satisfied by all common solutions of the input system; eliminating a part of dependent variables from the system if such elimination is possible; revealing hidden constraints on dependent variables, etc. Examples illustrating the use of the package are given. |
James, Glyn; Dyke, Philip; Burley, David; Clements, Dick; Craven, Matthew; Reis, Tim; Searl, John; Stander, Julian; Steele, Nigel; Wright, Jerry Advanced Modern Engineering Mathematics Book Pearson, 2018, ISBN: 978-1292174341. @book{dykeetal2018, title = {Advanced Modern Engineering Mathematics}, author = {Glyn James and Philip Dyke and David Burley and Dick Clements and Matthew Craven and Tim Reis and John Searl and Julian Stander and Nigel Steele and Jerry Wright}, isbn = {978-1292174341}, year = {2018}, date = {2018-07-30}, publisher = {Pearson}, keywords = {}, pubstate = {published}, tppubtype = {book} } |
Walker, David J; Craven, Matthew J Toward the Online Visualisation of Algorithm Performance for Parameter Selection Inproceedings Sim, K; Kaufmann, P (Ed.): International Conference on the Applications of Evolutionary Computation, pp. 547–560, Springer, 2018. @inproceedings{walker2018toward, title = {Toward the Online Visualisation of Algorithm Performance for Parameter Selection}, author = {David J Walker and Matthew J Craven}, editor = {K. Sim and P. Kaufmann}, doi = {10.1007/978-3-319-77538-8_38}, year = {2018}, date = {2018-04-01}, booktitle = {International Conference on the Applications of Evolutionary Computation}, volume = {LNCS 10784}, pages = {547--560}, publisher = {Springer}, abstract = {A visualisation method is presented that is intended to assist evolutionary algorithm users with the parametrisation of their algorithms. The visualisation method presents the convergence and diversity properties such that different parametrisations can be easily compared, and poor performing parameter sets can be easily identified and discarded. The efficacy of the visualisation is presented using a set of benchmark optimisation problems from the literature, as well as a benchmark water distribution network design problem. Results show that it is possible to observe the different performance caused by different parametrisations. Future work discusses the potential of this visualisation within an online tool that will enable a user to discard poor parametrisations as they execute to free up resources for better ones.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } A visualisation method is presented that is intended to assist evolutionary algorithm users with the parametrisation of their algorithms. The visualisation method presents the convergence and diversity properties such that different parametrisations can be easily compared, and poor performing parameter sets can be easily identified and discarded. The efficacy of the visualisation is presented using a set of benchmark optimisation problems from the literature, as well as a benchmark water distribution network design problem. Results show that it is possible to observe the different performance caused by different parametrisations. Future work discusses the potential of this visualisation within an online tool that will enable a user to discard poor parametrisations as they execute to free up resources for better ones. |
Broomhead, Nathan; Pauksztello, David; Ploog, David Discrete triangulated categories Journal Article Bulletin of the London Mathematical Society, 50 (1), pp. 174-188, 2018. @article{doi:10.1112/blms.12125, title = {Discrete triangulated categories}, author = {Nathan Broomhead and David Pauksztello and David Ploog}, url = {https://londmathsoc.onlinelibrary.wiley.com/doi/abs/10.1112/blms.12125}, doi = {10.1112/blms.12125}, year = {2018}, date = {2018-02-02}, journal = {Bulletin of the London Mathematical Society}, volume = {50}, number = {1}, pages = {174-188}, abstract = {Abstract We introduce and study several homological notions which generalise the discrete derived categories of D. Vossieck. As an application, we show that Vossieck discrete algebras have this property with respect to all bounded t-structures. We give many examples of triangulated categories regarding these notions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract We introduce and study several homological notions which generalise the discrete derived categories of D. Vossieck. As an application, we show that Vossieck discrete algebras have this property with respect to all bounded t-structures. We give many examples of triangulated categories regarding these notions. |
Xu, Dali; Stuhlmeier, Raphael; Stiassnie, Michael Assessing the size of a twin-cylinder wave energy converter designed for real sea-states Journal Article Ocean Engineering, 147 , pp. 243–255, 2018. @article{xu2018assessing, title = {Assessing the size of a twin-cylinder wave energy converter designed for real sea-states}, author = {Dali Xu and Raphael Stuhlmeier and Michael Stiassnie}, year = {2018}, date = {2018-01-01}, journal = {Ocean Engineering}, volume = {147}, pages = {243--255}, publisher = {Pergamon}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Stuhlmeier, R; Stiassnie, M Evolution of statistically inhomogeneous degenerate water wave quartets Journal Article Phil. Trans. R. Soc. A, 376 (2111), pp. 20170101, 2018. @article{stuhlmeier2018evolution, title = {Evolution of statistically inhomogeneous degenerate water wave quartets}, author = {R Stuhlmeier and M Stiassnie}, year = {2018}, date = {2018-01-01}, journal = {Phil. Trans. R. Soc. A}, volume = {376}, number = {2111}, pages = {20170101}, publisher = {The Royal Society}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Stuhlmeier, Raphael; Xu, Dali WEC Design Based on Refined Mean Annual Energy Production for the Israeli Mediterranean Coast Journal Article Journal of Waterway, Port, Coastal, and Ocean Engineering, 144 (4), pp. 06018002, 2018. @article{stuhlmeier2018wec, title = {WEC Design Based on Refined Mean Annual Energy Production for the Israeli Mediterranean Coast}, author = {Raphael Stuhlmeier and Dali Xu}, year = {2018}, date = {2018-01-01}, journal = {Journal of Waterway, Port, Coastal, and Ocean Engineering}, volume = {144}, number = {4}, pages = {06018002}, publisher = {American Society of Civil Engineers}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Walker, David J; Craven, Matthew J Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems Inproceedings Palermo, Italy, 2018. @inproceedings{walker2018visualising, title = {Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems}, author = {David J Walker and Matthew J Craven}, year = {2018}, date = {2018-01-01}, publisher = {Palermo, Italy}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Superintegrable relativistic systems in scalar background fields Journal Article J. Phys., (49), pp. 495203, 2018. @article{Ansell:2018dro, title = {Superintegrable relativistic systems in scalar background fields}, doi = {10.1088/1751-8121/aae9fb}, year = {2018}, date = {2018-01-01}, journal = {J. Phys.}, number = {49}, pages = {495203}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ilderton, A Screw-symmetric gravitational waves: a double copy of the vortex Journal Article Phys. Lett., B782 , pp. 22-27, 2018. @article{Ilderton:2018lsf, title = {Screw-symmetric gravitational waves: a double copy of the vortex}, author = {A Ilderton}, doi = {10.1016/j.physletb.2018.04.069}, year = {2018}, date = {2018-01-01}, journal = {Phys. Lett.}, volume = {B782}, pages = {22-27}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Heinzl, Tom; Ilderton, Anton; Seipt, Daniel Mode truncations and scattering in strong fields Journal Article Phys. Rev., D98 (1), pp. 016002, 2018. @article{Heinzl:2018xnv, title = {Mode truncations and scattering in strong fields}, author = {Tom Heinzl and Anton Ilderton and Daniel Seipt}, doi = {10.1103/PhysRevD.98.016002}, year = {2018}, date = {2018-01-01}, journal = {Phys. Rev.}, volume = {D98}, number = {1}, pages = {016002}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ilderton, Anton; Seipt, Daniel Backreaction on background fields: A coherent state approach Journal Article Phys. Rev., D97 (1), pp. 016007, 2018. @article{Ilderton:2017xbj, title = {Backreaction on background fields: A coherent state approach}, author = {Anton Ilderton and Daniel Seipt}, doi = {10.1103/PhysRevD.97.016007}, year = {2018}, date = {2018-01-01}, journal = {Phys. Rev.}, volume = {D97}, number = {1}, pages = {016007}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Cole, J M; others, Experimental evidence of radiation reaction in the collision of a high-intensity laser pulse with a laser-wakefield accelerated electron beam Journal Article Phys. Rev., X8 (1), pp. 011020, 2018. @article{Cole:2017zca, title = {Experimental evidence of radiation reaction in the collision of a high-intensity laser pulse with a laser-wakefield accelerated electron beam}, author = {J M Cole and others}, doi = {10.1103/PhysRevX.8.011020}, year = {2018}, date = {2018-01-01}, journal = {Phys. Rev.}, volume = {X8}, number = {1}, pages = {011020}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2017 |
Dash, William; Craven, Matthew J Exploring Botnet Evolution via Multidimensional Models and Visualisation Inproceedings Livraga, G; Mitchell, C (Ed.): International Workshop on Security and Trust Management, pp. 72–88, Springer Springer, 2017. @inproceedings{dash2017exploring, title = {Exploring Botnet Evolution via Multidimensional Models and Visualisation}, author = {William Dash and Matthew J Craven}, editor = {G. Livraga and C. Mitchell}, doi = {10.1007/978-3-319-68063-7_5}, year = {2017}, date = {2017-09-30}, booktitle = {International Workshop on Security and Trust Management}, volume = {LNCS 10547}, pages = {72--88}, publisher = {Springer}, organization = {Springer}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Craven, Matthew J; Graham, David I Exploring the (efficient) frontiers of portfolio optimization Inproceedings Bosman, P (Ed.): Proceedings of the Genetic and Evolutionary Computation Conference Companion, pp. 19–20, ACM ACM, 2017. @inproceedings{craven2017exploring, title = {Exploring the (efficient) frontiers of portfolio optimization}, author = {Matthew J Craven and David I Graham}, editor = {P. Bosman}, doi = {10.1145/3067695.3082036}, year = {2017}, date = {2017-07-15}, booktitle = {Proceedings of the Genetic and Evolutionary Computation Conference Companion}, pages = {19--20}, publisher = {ACM}, organization = {ACM}, abstract = {The cardinality-constrained portfolio optimization problem is NP-hard. Its Pareto front (or the Efficient Frontier - EF) is usually calculated by stochastic algorithms, including EAs. However, in certain cases the EF may be decomposed into a union of sub-EFs. In this work we propose a systematic process of excluding sub-EFs dominated by others, enabling us to calculate non-dominated sub-EFs. We then calculate whole EFs to a high degree of accuracy for small cardinalities, providing an alternative to EAs in those cases. We can use also this to provide insight into EAs on the problem.}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The cardinality-constrained portfolio optimization problem is NP-hard. Its Pareto front (or the Efficient Frontier - EF) is usually calculated by stochastic algorithms, including EAs. However, in certain cases the EF may be decomposed into a union of sub-EFs. In this work we propose a systematic process of excluding sub-EFs dominated by others, enabling us to calculate non-dominated sub-EFs. We then calculate whole EFs to a high degree of accuracy for small cardinalities, providing an alternative to EAs in those cases. We can use also this to provide insight into EAs on the problem. |
Heinzl, Thomas; Ilderton, Anton Exact classical and quantum dynamics in background electromagnetic fields Journal Article Physical Review Letters, 118 (11), pp. 113202, 2017, (editor's suggestion). @article{Heinzl:2017zsr, title = {Exact classical and quantum dynamics in background electromagnetic fields}, author = {Thomas Heinzl and Anton Ilderton}, url = {http://arxiv.org/abs/arXiv:1701.09168}, doi = {https://doi.org/10.1103/PhysRevLett.118.113202}, year = {2017}, date = {2017-01-31}, journal = {Physical Review Letters}, volume = {118}, number = {11}, pages = {113202}, abstract = {Analytic results for (Q)ED processes in external fields are limited to a few special cases, such as plane waves. However, the strong focussing of intense laser fields implies a need to go beyond the plane wave model. By exploiting Poincare symmetry and superintegrability we show how to construct, and solve without approximation, new models of laser-particle interactions. We illustrate the method with a model of a radially polarised (TM) laser beam, for which we exactly determine the classical orbits and quantum wave functions. Including in this way the effects of transverse field structure should improve predictions and analyses for experiments at intense laser facilities.}, note = {editor's suggestion}, keywords = {}, pubstate = {published}, tppubtype = {article} } Analytic results for (Q)ED processes in external fields are limited to a few special cases, such as plane waves. However, the strong focussing of intense laser fields implies a need to go beyond the plane wave model. By exploiting Poincare symmetry and superintegrability we show how to construct, and solve without approximation, new models of laser-particle interactions. We illustrate the method with a model of a radially polarised (TM) laser beam, for which we exactly determine the classical orbits and quantum wave functions. Including in this way the effects of transverse field structure should improve predictions and analyses for experiments at intense laser facilities. |
Heinzl, Thomas; Ilderton, Anton Superintegrable relativistic systems in spacetime-dependent background fields Journal Article e-Print: arXiv:1701.09168 [math-ph] , 2017. @article{Heinzl:2017blqb, title = {Superintegrable relativistic systems in spacetime-dependent background fields}, author = {Thomas Heinzl and Anton Ilderton}, url = {http://arxiv.org/pdf/1701.09168.pdf}, year = {2017}, date = {2017-01-31}, journal = {e-Print: arXiv:1701.09168 [math-ph] }, abstract = {We consider a relativistic charged particle in background electromagnetic fields depending on both space and time. We identify which symmetries of the fields automatically generate integrals (conserved quantities) of the charge motion, accounting fully for relativistic and gauge invariance. Using this we present new examples of superintegrable relativistic systems. This includes examples where the integrals of motion are quadratic or nonpolynomial in the canonical momenta.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We consider a relativistic charged particle in background electromagnetic fields depending on both space and time. We identify which symmetries of the fields automatically generate integrals (conserved quantities) of the charge motion, accounting fully for relativistic and gauge invariance. Using this we present new examples of superintegrable relativistic systems. This includes examples where the integrals of motion are quadratic or nonpolynomial in the canonical momenta. |
Cardinali, Alessandro ; Nason, Guy P Locally Stationary Wavelet Packet Processes: Basis Selection and Model Fitting Journal Article Journal of Time Series Analysis, to appear , 2017. @article{cardinali2017locally, title = {Locally Stationary Wavelet Packet Processes: Basis Selection and Model Fitting}, author = {Cardinali, Alessandro and Nason, Guy P}, year = {2017}, date = {2017-01-01}, journal = {Journal of Time Series Analysis}, volume = {to appear}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Xu, Dali; Stuhlmeier, Raphael; Stiassnie, Michael Harnessing wave power in open seas II: very large arrays of wave-energy converters for 2D sea states Journal Article Journal of Ocean Engineering and Marine Energy, 3 (2), pp. 151–160, 2017. @article{xu2017harnessing, title = {Harnessing wave power in open seas II: very large arrays of wave-energy converters for 2D sea states}, author = {Dali Xu and Raphael Stuhlmeier and Michael Stiassnie}, year = {2017}, date = {2017-01-01}, journal = {Journal of Ocean Engineering and Marine Energy}, volume = {3}, number = {2}, pages = {151--160}, publisher = {Springer International Publishing}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Blackburn, T G; Ilderton, A; Murphy, C D; Marklund, M Scaling laws for positron production in laser–electron-beam collisions Journal Article Phys. Rev., (2), pp. 022128, 2017. @article{Blackburn:2017dpn, title = {Scaling laws for positron production in laser–electron-beam collisions}, author = {T G Blackburn and A Ilderton and C D Murphy and M Marklund}, doi = {10.1103/PhysRevA.96.022128}, year = {2017}, date = {2017-01-01}, journal = {Phys. Rev.}, number = {2}, pages = {022128}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Heinzl, Tom; Ilderton, Anton Superintegrable relativistic systems in spacetime-dependent background fields Journal Article J. Phys., (34), pp. 345204, 2017. @article{Heinzl:2017blqb, title = {Superintegrable relativistic systems in spacetime-dependent background fields}, author = {Tom Heinzl and Anton Ilderton}, doi = {10.1088/1751-8121/aa7fa3}, year = {2017}, date = {2017-01-01}, journal = {J. Phys.}, number = {34}, pages = {345204}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2016 |
Craven, Matthew J; Robertz, Daniel A parallel evolutionary approach to solving systems of equations in polycyclic groups Journal Article Groups Complexity Cryptology, 8 (2), pp. 109–125, 2016. @article{craven2016parallel, title = {A parallel evolutionary approach to solving systems of equations in polycyclic groups}, author = {Matthew J Craven and Daniel Robertz}, doi = {10.1515/gcc-2016-0012}, year = {2016}, date = {2016-11-01}, journal = {Groups Complexity Cryptology}, volume = {8}, number = {2}, pages = {109--125}, publisher = {De Gruyter}, abstract = {The Anshel–Anshel–Goldfeld (AAG) key exchange protocol is based upon the multiple conjugacy problem for a finitely-presented group. The hardness in breaking this protocol relies on the supposed difficulty in solving the corresponding equations for the conjugating element in the group. Two such protocols based on polycyclic groups as a platform were recently proposed and were shown to be resistant to length-based attack. In this article we propose a parallel evolutionary approach which runs on multicore high-performance architectures. The approach is shown to be more efficient than previous attempts to break these protocols, and also more successful. Comprehensive data of experiments run with a GAP implementation are provided and compared to the results of earlier length-based attacks. These demonstrate that the proposed platform is not as secure as first thought and also show that existing measures of cryptographic complexity are not optimal. A more accurate alternative measure is suggested. Finally, a linear algebra attack for one of the protocols is introduced.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Anshel–Anshel–Goldfeld (AAG) key exchange protocol is based upon the multiple conjugacy problem for a finitely-presented group. The hardness in breaking this protocol relies on the supposed difficulty in solving the corresponding equations for the conjugating element in the group. Two such protocols based on polycyclic groups as a platform were recently proposed and were shown to be resistant to length-based attack. In this article we propose a parallel evolutionary approach which runs on multicore high-performance architectures. The approach is shown to be more efficient than previous attempts to break these protocols, and also more successful. Comprehensive data of experiments run with a GAP implementation are provided and compared to the results of earlier length-based attacks. These demonstrate that the proposed platform is not as secure as first thought and also show that existing measures of cryptographic complexity are not optimal. A more accurate alternative measure is suggested. Finally, a linear algebra attack for one of the protocols is introduced. |
McCourt, T A; Schroeder, J Z Self-embeddings of doubled affine Steiner triple systems Journal Article Australas. J. Combin., 1 (66), pp. p.23, 2016, ISSN: 1034-4942. @article{McCourt2016, title = {Self-embeddings of doubled affine Steiner triple systems}, author = {McCourt, T.A. and Schroeder, J.Z.}, url = {http://ajc.maths.uq.edu.au/?page=get_volumes&volume=66}, issn = {1034-4942}, year = {2016}, date = {2016-08-14}, journal = {Australas. J. Combin.}, volume = {1}, number = {66}, pages = {p.23}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Heinzl, Thomas ; Ilderton, Anton ; King, Ben Classical and quantum particle dynamics in univariate background fields Journal Article Physical Review D, 94 , pp. 065039, 2016, (arXiv:1607.07449). @article{heinzl2016classical, title = {Classical and quantum particle dynamics in univariate background fields}, author = {Heinzl, Thomas and Ilderton, Anton and King, Ben}, doi = {http://dx.doi.org/10.1103/PhysRevD.94.065039}, year = {2016}, date = {2016-07-15}, journal = {Physical Review D}, volume = {94}, pages = {065039}, abstract = {We investigate deviations from the plane wave model in the interaction of charged particles with strong electromagnetic fields. A general result is that integrability of the dynamics is lost when going from lightlike to timelike or spacelike field dependence. For a special scenario in the classical regime we show how the radiation spectrum in the spacelike (undulator) case becomes well-approximated by the plane wave model in the high-energy limit, despite the two systems being Lorentz inequivalent. In the quantum problem, there is no analogue of the WKB-exact Volkov solution. Nevertheless, WKB and uniform-WKB approaches give good approximations in all cases considered. Other approaches that reduce the underlying differential equations from second to first order are found to miss the correct physics for situations corresponding to barrier transmission and wide-angle scattering.}, note = {arXiv:1607.07449}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate deviations from the plane wave model in the interaction of charged particles with strong electromagnetic fields. A general result is that integrability of the dynamics is lost when going from lightlike to timelike or spacelike field dependence. For a special scenario in the classical regime we show how the radiation spectrum in the spacelike (undulator) case becomes well-approximated by the plane wave model in the high-energy limit, despite the two systems being Lorentz inequivalent. In the quantum problem, there is no analogue of the WKB-exact Volkov solution. Nevertheless, WKB and uniform-WKB approaches give good approximations in all cases considered. Other approaches that reduce the underlying differential equations from second to first order are found to miss the correct physics for situations corresponding to barrier transmission and wide-angle scattering. |
Stander, Julian ; Dalla Valle, Luciana ; Eales, John ; Baldino, Andrea ; Cortina Borja, Mario The EU referendum: extracting insights from Facebook using R Online 2016. @online{stander2016eu, title = {The EU referendum: extracting insights from Facebook using R}, author = {Stander, Julian and Dalla Valle, Luciana and Eales, John and Baldino, Andrea and Cortina Borja, Mario}, year = {2016}, date = {2016-06-20}, journal = {Significance Magazine}, keywords = {}, pubstate = {published}, tppubtype = {online} } |
Seipt, Daniel; Heinzl, Thomas; Marklund, Mattias; Bulanov, Stepan S Depletion of intense fields Journal Article arXiv:1605.00633 [hep-ph], 2016. @article{Seipt:2016fyu, title = {Depletion of intense fields }, author = {Daniel Seipt and Thomas Heinzl and Mattias Marklund and Stepan S. Bulanov}, url = {http://arxiv.org/pdf/1605.00633.pdf}, year = {2016}, date = {2016-05-02}, journal = { arXiv:1605.00633 [hep-ph]}, abstract = {The interaction of charged particles and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. These are usually described in the framework of the external field approximation, where the electromagnetic field is assumed to have infinite energy. However, the multi-photon nature of these processes implies the absorption of a significant number of photons, which scales as the external field amplitude cubed. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. We provide relevant estimates for this depletion and find it to become important in the interaction between fields of amplitude a0~10^3 and electron bunches with charges of the order of nC. }, keywords = {}, pubstate = {published}, tppubtype = {article} } The interaction of charged particles and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. These are usually described in the framework of the external field approximation, where the electromagnetic field is assumed to have infinite energy. However, the multi-photon nature of these processes implies the absorption of a significant number of photons, which scales as the external field amplitude cubed. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. We provide relevant estimates for this depletion and find it to become important in the interaction between fields of amplitude a0~10^3 and electron bunches with charges of the order of nC. |
Pang, CL ; Alcock, R; Pilkington, N; Reis, T; Roobottom, C Clinical Radiology, 71 , pp. 750-757, 2016. @article{pang2016determining, title = {Determining the haemodynamic significance of arterial stenosis: the relationship between CT angiography, computational fluid dynamics, and non-invasive fractional flow reserve}, author = {Pang, CL and Alcock, R and Pilkington, N and Reis, T and Roobottom, C}, doi = {doi:10.1016/j.crad.2016.03.001}, year = {2016}, date = {2016-04-06}, journal = {Clinical Radiology}, volume = {71}, pages = {750-757}, publisher = {Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Wei Y. Kypriaos T., O’Neill Huang Rifas-Shiman P D S S S L; B.S., Cooper Statistical Methods in Medical Research, 2016. @article{Wei2016, title = {Evaluating hospital infection control measures for antimicrobial-resistant pathogens using stochastic transmission models: Application to vancomycin-resistant enterococci in intensive care units }, author = {Wei Y., Kypriaos T., O’Neill P.D., Huang S.S., Rifas-Shiman S.L. and Cooper B.S.}, url = {http://smm.sagepub.com/content/early/2016/01/18/0962280215627299.abstract}, year = {2016}, date = {2016-03-16}, journal = {Statistical Methods in Medical Research}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
King, Ben; Heinzl, Thomas Measuring Vacuum Polarisation with High Power Lasers Journal Article High Power Laser Science and Engineering, 4 , pp. e5, 2016, (arXiv:1510.08456). @article{King:2015tba, title = {Measuring Vacuum Polarisation with High Power Lasers}, author = {Ben King and Thomas Heinzl}, doi = {http://dx.doi.org/10.1017/hpl.2016.1}, year = {2016}, date = {2016-03-02}, journal = {High Power Laser Science and Engineering}, volume = {4}, pages = {e5}, abstract = {When exposed to intense electromagnetic fields, the quantum vacuum is expected to exhibit properties of a polarisable medium akin to a weakly nonlinear dielectric material. Various schemes have been proposed to measure such vacuum polarisation effects using a combination of high power lasers. Motivated by several planned experiments, we provide an overview of experimental signatures that have been suggested to confirm this prediction of quantum electrodynamics of real photon-photon scattering.}, note = {arXiv:1510.08456}, keywords = {}, pubstate = {published}, tppubtype = {article} } When exposed to intense electromagnetic fields, the quantum vacuum is expected to exhibit properties of a polarisable medium akin to a weakly nonlinear dielectric material. Various schemes have been proposed to measure such vacuum polarisation effects using a combination of high power lasers. Motivated by several planned experiments, we provide an overview of experimental signatures that have been suggested to confirm this prediction of quantum electrodynamics of real photon-photon scattering. |
Stander, Julian ; Dalla Valle, Luciana ; Cortina Borja, Mario Statistically, how long can Pope Francis expect to live? Journal Article Significance Magazine, 13 (1), pp. 9–10, 2016. @article{stander2016statistically, title = {Statistically, how long can Pope Francis expect to live?}, author = {Stander, Julian and Dalla Valle, Luciana and Cortina Borja, Mario}, year = {2016}, date = {2016-02-01}, journal = {Significance Magazine}, volume = {13}, number = {1}, pages = {9--10}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Schlenvoigt, Hans-Peter; Heinzl, Tom; Schramm, Ulrich; Cowan, Thomas E; Sauerbrey, Roland Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers: A feasibility study Journal Article Physica Scripta, 91 , pp. 023010 , 2016. @article{Schlenvoigt2016, title = {Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers: A feasibility study}, author = {Hans-Peter Schlenvoigt and Tom Heinzl and Ulrich Schramm and Thomas E. Cowan and Roland Sauerbrey}, doi = {http://dx.doi.org/10.1088/0031-8949/91/2/023010}, year = {2016}, date = {2016-01-18}, journal = {Physica Scripta}, volume = {91}, pages = {023010 }, abstract = {We study the feasibility of measuring vacuum birefringence by probing the focus of a high intensity optical laser with an x-ray free electron laser (XFEL). This amounts to performing a new type of QED precision experiment, employing only laser pulses, hence space- and time dependent fields. To set the stage, we briefly review the status of QED precision tests and then focus on the example of vacuum birefringence. Adopting a realistic laser beam model in terms of pulsed Gaussian beams we calculate the induced phase shift and translate it into an experimental signal, counting the number of photons with flipped polarization. We carefully design a detailed experiment at the European XFEL operating in self-seeded mode, supplemented by a petawatt class optical laser via the HIBEF project. Assuming all components to represent the current state of the art, in particular the x-ray polarizers, realistic estimates of signal-to-noise ratios plus ensuing acquisition times are provided. This is accompanied by a statistical analysis of the impact of poor laser focus overlap either due to timing and pointing jitter as well as limited alignment accuracy. A number of parasitic effects are analyzed together with appropriate countermeasures. We conclude that vacuum birefringence can indeed be measured upon combining an XFEL with a high-power optical laser if depolarization effects in the x-ray lenses can be controlled.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We study the feasibility of measuring vacuum birefringence by probing the focus of a high intensity optical laser with an x-ray free electron laser (XFEL). This amounts to performing a new type of QED precision experiment, employing only laser pulses, hence space- and time dependent fields. To set the stage, we briefly review the status of QED precision tests and then focus on the example of vacuum birefringence. Adopting a realistic laser beam model in terms of pulsed Gaussian beams we calculate the induced phase shift and translate it into an experimental signal, counting the number of photons with flipped polarization. We carefully design a detailed experiment at the European XFEL operating in self-seeded mode, supplemented by a petawatt class optical laser via the HIBEF project. Assuming all components to represent the current state of the art, in particular the x-ray polarizers, realistic estimates of signal-to-noise ratios plus ensuing acquisition times are provided. This is accompanied by a statistical analysis of the impact of poor laser focus overlap either due to timing and pointing jitter as well as limited alignment accuracy. A number of parasitic effects are analyzed together with appropriate countermeasures. We conclude that vacuum birefringence can indeed be measured upon combining an XFEL with a high-power optical laser if depolarization effects in the x-ray lenses can be controlled. |
Dalla Valle, Luciana ; De Giuli, Maria Elena ; Tarantola, Claudia ; Manelli, Claudio Default Probability Estimation via Pair Copula Constructions Journal Article European Journal of Operational Research, 249 (1), pp. 298–311, 2016. @article{dalla2016defaultb, title = {Default Probability Estimation via Pair Copula Constructions}, author = {Dalla Valle, Luciana and De Giuli, Maria Elena and Tarantola, Claudia and Manelli, Claudio}, year = {2016}, date = {2016-01-03}, journal = {European Journal of Operational Research}, volume = {249}, number = {1}, pages = {298--311}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Stiassnie, Michael; Kadri, Usama; Stuhlmeier, Raphael Harnessing wave power in open seas Journal Article Journal of Ocean Engineering and Marine Energy, 2 (1), pp. 47–57, 2016. @article{stiassnie2016harnessing, title = {Harnessing wave power in open seas}, author = {Michael Stiassnie and Usama Kadri and Raphael Stuhlmeier}, year = {2016}, date = {2016-01-01}, journal = {Journal of Ocean Engineering and Marine Energy}, volume = {2}, number = {1}, pages = {47--57}, publisher = {Springer International Publishing}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Stuhlmeier, Raphael; Stiassnie, Michael Adapting Havelock's wave-maker theorem to acoustic-gravity waves Journal Article IMA Journal of Applied Mathematics, 81 (4), pp. 631–646, 2016. @article{stuhlmeier2016adapting, title = {Adapting Havelock's wave-maker theorem to acoustic-gravity waves}, author = {Raphael Stuhlmeier and Michael Stiassnie}, year = {2016}, date = {2016-01-01}, journal = {IMA Journal of Applied Mathematics}, volume = {81}, number = {4}, pages = {631--646}, publisher = {Oxford University Press}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Xu, Dali; Stuhlmeier, Raphael; Stiassnie, Michael Parameter based design of a twin-cylinder wave energy converter for real sea-states Journal Article arXiv preprint arXiv:1605.00428, 2016. @article{xu2016parameter, title = {Parameter based design of a twin-cylinder wave energy converter for real sea-states}, author = {Dali Xu and Raphael Stuhlmeier and Michael Stiassnie}, year = {2016}, date = {2016-01-01}, journal = {arXiv preprint arXiv:1605.00428}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Fritzsch, Patrick; Garron, Nicolas; Heitger, Jochen Non-perturbative tests of continuum HQET through small-volume two-flavour QCD Journal Article JHEP, 01 , pp. 093, 2016. @article{Fritzsch:2015eka, title = {Non-perturbative tests of continuum HQET through small-volume two-flavour QCD}, author = { Patrick Fritzsch and Nicolas Garron and Jochen Heitger}, doi = {10.1007/JHEP01(2016)093}, year = {2016}, date = {2016-01-01}, journal = {JHEP}, volume = {01}, pages = {093}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Safaa K. Kadhem Paul Hewson, Irene Kaimi Recursive Deviance Information Criterion for the Hidden Markov Model Journal Article International Journal of Statistics and Probability, 5 (1), 2016. @article{safaa2016recursive, title = {Recursive Deviance Information Criterion for the Hidden Markov Model}, author = {Safaa K. Kadhem, Paul Hewson, Irene Kaimi}, year = {2016}, date = {2016-01-01}, journal = {International Journal of Statistics and Probability}, volume = {5}, number = {1}, publisher = {Canadian Center of Science and Education (CCSE)}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ilderton, Anton ; Torgrimsson, Greger The worldline approach to helicity flip in plane waves Journal Article arXiv preprint arXiv:1601.05021, 2016. @article{ilderton2016worldline, title = {The worldline approach to helicity flip in plane waves}, author = {Ilderton, Anton and Torgrimsson, Greger}, year = {2016}, date = {2016-01-01}, journal = {arXiv preprint arXiv:1601.05021}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Donovan, Diane M; Griggs, Terry S; McCourt, Thomas A; Opršal, Jakub ; Stanovsk'y, David Distributive and Anti-distributive Mendelsohn Ŧriple Systems Journal Article Canad. Math. Bull., 59 (1), pp. 36–49, 2016, ISSN: 0008-4395. @article{MR3451896, title = {Distributive and Anti-distributive Mendelsohn Ŧriple Systems}, author = {Donovan, Diane M. and Griggs, Terry S. and McCourt, Thomas A. and Opršal, Jakub and Stanovsk'y, David}, url = {http://dx.doi.org/10.4153/CMB-2015-053-2}, doi = {10.4153/CMB-2015-053-2}, issn = {0008-4395}, year = {2016}, date = {2016-01-01}, journal = {Canad. Math. Bull.}, volume = {59}, number = {1}, pages = {36--49}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Griggs, Terry S; McCourt, Thomas A Biembeddings of Symmetric $n$-Cycle Systems Journal Article Graphs Combin., 32 (1), pp. 147–160, 2016, ISSN: 0911-0119. @article{MR3436956, title = {Biembeddings of Symmetric $n$-Cycle Systems}, author = {Griggs, Terry S. and McCourt, Thomas A.}, url = {http://dx.doi.org/10.1007/s00373-015-1538-1}, doi = {10.1007/s00373-015-1538-1}, issn = {0911-0119}, year = {2016}, date = {2016-01-01}, journal = {Graphs Combin.}, volume = {32}, number = {1}, pages = {147--160}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Publications
2020 |
An Exact Algorithm for Small-Cardinality Constrained Portfolio Optimisation Journal Article Journal of the Operational Research Society, 2020. |
Modern Engineering Mathematics Book Forthcoming Pearson, Forthcoming. |
2019 |
Identifying Good Algorithm Parameters in Evolutionary Multi- and Many-Objective Optimisation: A Visualisation Approach Journal Article Applied Soft Computing, pp. 105902, 2019. |
Efficient Frontiers in Portfolio Optimisation with Minimum Proportion Constraints Inproceedings Proceedings of the Companion Publication of the 2019 Annual Conference on Genetic and Evolutionary Computation, pp. 358-359, 2019. |
The icosahedra of edge length 1 Journal Article Journal of Algebra, 545 , pp. 4–26, 2019. |
Nonlinear dispersion for ocean surface waves Journal Article Journal of Fluid Mechanics, 859 , pp. 49–58, 2019. |
Algorithmic Approach to Strong Consistency Analysis of Finite Difference Approximations to PDE Systems Inproceedings Proceedings of the 2019 International Symposium on Symbolic and Algebraic Computation, 15-18 July 2019, Beihang University, Beijing, China, pp. 163–170, 2019. |
2018 |
"The Mathematics Problem": A Plymouth Foundation Year Case Study Journal Article J. Foundation Year Network, 1 , pp. 23-35, 2018. |
Thick subcategories of discrete derived categories Journal Article Advances in Mathematics, 336 , pp. 242 - 298, 2018, ISSN: 0001-8708. |
Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems Inproceedings et al., La Loggia G (Ed.): Palermo, Italy, 2018. |
The MAPLE package TDDS for computing Thomas decompositions of systems of nonlinear PDEs Journal Article Computer Physics Communications, 234 , pp. 202–215, 2018. |
Advanced Modern Engineering Mathematics Book Pearson, 2018, ISBN: 978-1292174341. |
Toward the Online Visualisation of Algorithm Performance for Parameter Selection Inproceedings Sim, K; Kaufmann, P (Ed.): International Conference on the Applications of Evolutionary Computation, pp. 547–560, Springer, 2018. |
Discrete triangulated categories Journal Article Bulletin of the London Mathematical Society, 50 (1), pp. 174-188, 2018. |
Assessing the size of a twin-cylinder wave energy converter designed for real sea-states Journal Article Ocean Engineering, 147 , pp. 243–255, 2018. |
Evolution of statistically inhomogeneous degenerate water wave quartets Journal Article Phil. Trans. R. Soc. A, 376 (2111), pp. 20170101, 2018. |
WEC Design Based on Refined Mean Annual Energy Production for the Israeli Mediterranean Coast Journal Article Journal of Waterway, Port, Coastal, and Ocean Engineering, 144 (4), pp. 06018002, 2018. |
Visualising the Operation of Evolutionary Algorithms Optimising Water Distribution Network Design Problems Inproceedings Palermo, Italy, 2018. |
Superintegrable relativistic systems in scalar background fields Journal Article J. Phys., (49), pp. 495203, 2018. |
Screw-symmetric gravitational waves: a double copy of the vortex Journal Article Phys. Lett., B782 , pp. 22-27, 2018. |
Mode truncations and scattering in strong fields Journal Article Phys. Rev., D98 (1), pp. 016002, 2018. |
Backreaction on background fields: A coherent state approach Journal Article Phys. Rev., D97 (1), pp. 016007, 2018. |
Experimental evidence of radiation reaction in the collision of a high-intensity laser pulse with a laser-wakefield accelerated electron beam Journal Article Phys. Rev., X8 (1), pp. 011020, 2018. |
2017 |
Exploring Botnet Evolution via Multidimensional Models and Visualisation Inproceedings Livraga, G; Mitchell, C (Ed.): International Workshop on Security and Trust Management, pp. 72–88, Springer Springer, 2017. |
Exploring the (efficient) frontiers of portfolio optimization Inproceedings Bosman, P (Ed.): Proceedings of the Genetic and Evolutionary Computation Conference Companion, pp. 19–20, ACM ACM, 2017. |
Exact classical and quantum dynamics in background electromagnetic fields Journal Article Physical Review Letters, 118 (11), pp. 113202, 2017, (editor's suggestion). |
Superintegrable relativistic systems in spacetime-dependent background fields Journal Article e-Print: arXiv:1701.09168 [math-ph] , 2017. |
Locally Stationary Wavelet Packet Processes: Basis Selection and Model Fitting Journal Article Journal of Time Series Analysis, to appear , 2017. |
Harnessing wave power in open seas II: very large arrays of wave-energy converters for 2D sea states Journal Article Journal of Ocean Engineering and Marine Energy, 3 (2), pp. 151–160, 2017. |
Scaling laws for positron production in laser–electron-beam collisions Journal Article Phys. Rev., (2), pp. 022128, 2017. |
Superintegrable relativistic systems in spacetime-dependent background fields Journal Article J. Phys., (34), pp. 345204, 2017. |
2016 |
A parallel evolutionary approach to solving systems of equations in polycyclic groups Journal Article Groups Complexity Cryptology, 8 (2), pp. 109–125, 2016. |
Self-embeddings of doubled affine Steiner triple systems Journal Article Australas. J. Combin., 1 (66), pp. p.23, 2016, ISSN: 1034-4942. |
Classical and quantum particle dynamics in univariate background fields Journal Article Physical Review D, 94 , pp. 065039, 2016, (arXiv:1607.07449). |
The EU referendum: extracting insights from Facebook using R Online 2016. |
Depletion of intense fields Journal Article arXiv:1605.00633 [hep-ph], 2016. |
Clinical Radiology, 71 , pp. 750-757, 2016. |
Statistical Methods in Medical Research, 2016. |
Measuring Vacuum Polarisation with High Power Lasers Journal Article High Power Laser Science and Engineering, 4 , pp. e5, 2016, (arXiv:1510.08456). |
Statistically, how long can Pope Francis expect to live? Journal Article Significance Magazine, 13 (1), pp. 9–10, 2016. |
Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers: A feasibility study Journal Article Physica Scripta, 91 , pp. 023010 , 2016. |
Default Probability Estimation via Pair Copula Constructions Journal Article European Journal of Operational Research, 249 (1), pp. 298–311, 2016. |
Harnessing wave power in open seas Journal Article Journal of Ocean Engineering and Marine Energy, 2 (1), pp. 47–57, 2016. |
Adapting Havelock's wave-maker theorem to acoustic-gravity waves Journal Article IMA Journal of Applied Mathematics, 81 (4), pp. 631–646, 2016. |
Parameter based design of a twin-cylinder wave energy converter for real sea-states Journal Article arXiv preprint arXiv:1605.00428, 2016. |
Non-perturbative tests of continuum HQET through small-volume two-flavour QCD Journal Article JHEP, 01 , pp. 093, 2016. |
Recursive Deviance Information Criterion for the Hidden Markov Model Journal Article International Journal of Statistics and Probability, 5 (1), 2016. |
The worldline approach to helicity flip in plane waves Journal Article arXiv preprint arXiv:1601.05021, 2016. |
Distributive and Anti-distributive Mendelsohn Ŧriple Systems Journal Article Canad. Math. Bull., 59 (1), pp. 36–49, 2016, ISSN: 0008-4395. |
Biembeddings of Symmetric $n$-Cycle Systems Journal Article Graphs Combin., 32 (1), pp. 147–160, 2016, ISSN: 0911-0119. |