# Staff profile

## Professor Iain Stewart

Professor

MA PhD FBCS CITP

Affiliation | Room number | Telephone |
---|---|---|

Professor in the Department of Computer Science | MCS 2005 | +44 (0) 191 33 41720 |

### Biography

I am a Professor in the School of Engineering and Computing Sciences. I read mathematics at Christ Church, Oxford (1980-83) before completing my PhD in mathematics at Queen Mary College, University of London (1983-86). I was then appointed to a Lecturership in the Computing Laboratory, University of Newcastle upon Tyne in 1986 before moving to a Lecturership in the Department of Computer Science, University of Wales Swansea in 1992. I was later appointed Senior Lecturer (1994) and then Reader (1995) before becoming Professor of Computer Science at Leicester in 1996. I moved to the Department of Computer Science at Durham as Professor in 2002.

I have a number of positions within the mathematics and computer science community which include the following: I am a member of the UK Computing Research Committee (UKCRC), having previously been on the Executive; I am a member of the Research Committee of the BCS Academy of Computing; I am a member of the EPSRC Computing College; I am an Editorial Advisor to the London Mathematical Society Journal of Computation and Mathematics; I am an Editor of the Journal of Discrete Algorithms; and I am an Associate Editor of The Computer Journal. In the past I have been: a Member of Council of the London Mathematical Society; Chair of the Computer Science Committee of the London Mathematical Society; Co-ordinator of the joint EPSRC and London Mathematical Society MathFIT (Mathematics for Information Technology) initiative; President of the British Colloquium for Theoretical Computer Science (BCTCS); and President of the European Association for Computer Science Logic (EACSL).

I have varied research interests including: computational complexity; finite model theory and descriptive complexity; graph theory and algorithms; interconnection networks for parallel and distributed computing; theoretical aspects of artificial intelligence; and group theory.

### Research interests

- graph theory and algorithms
- interconnection networks for parallel and distributed computing
- theoretical aspects of artificial intelligence
- group theory
- computational complexity
- finite model theory and descriptive complexity

### Research groups

- Algorithms and Complexity

### Publications

Chapter in book

Conference Paper

- Stewart, I.A. (2015), On the mathematics of data centre network topologies, in Kosowski, A. & Walukiewicz, I. eds, Lecture Notes in Computer Science
**9210**:__20th International Symposium on Fundamentals of Computation Theory__. Gdańsk, Poland, Springer, Cham, 283-295. - Kiasari, A.E., Navaridas, J. & Stewart, I.A. (2015), Routing packets on DPillar data centre networks, in Wang, G., Zomaya, A., Perez, G.M. & Li, K. eds, Lecture Notes in Computer Science
**9531**:__15th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP__. Zhangjiajie, China, Springer, 329-343. - Erickson, A., Kiasari, A.E., Navaridas, J. & Stewart, I.A. (2015), An efficient shortest path routing algorithm in the data centre network DPillar, in Lu, Z., Kim, D., Wu, W., Li, W. & Du, D.-Z. eds, Lecture Notes in Computer Science
**9486**:__9th Annual International Conference on Combinatorial Optimization and Applications, COCOA__. Houston, USA, Springer, 209-220. - Erickson, A., Kiasari, A., Navaridas, J. & Stewart, I.A. (2015), Routing algorithms for recursively-defined data centre networks,
**3**:__13th IEEE International Symposium on Parallel and Distributed Processing with Applications__. Helsinki, IEEE Computer Society Press, Piscataway, NJ, 84-91. - Dawson, L. & Stewart, I.A. (2014), Accelerating ant colony optimization-based edge detection on the GPU using CUDA,
__2014 IEEE Congress on Evolutionary Computation (CEC)__. Beijing, China, IEEE, Piscataway, NJ, 1736-1743. - Stewart, I.A. (2014), Improved routing in the data centre networks HCN and BCN,
__2nd International Symposium on Computing and Networking - Across Practical Development and Theoretical Research__. Shizuoka, Japan, IEEE Computer Society Press, Shizuoka, 212-218. - Dawson, L. & Stewart, I.A. (2013), Improving Ant Colony Optimization performance on the GPU using CUDA,
__2013 IEEE Congress on Evolutionary Computation__. Cancun, Mexico, IEEE, 1901-1908 - Dawson, L. & Stewart, I.A. (2013), Candidate set parallelization strategies for Ant Colony Optimization on the GPU, in Kołodziej, J., Di Martino, B., Talia,D. & Xiong, K. eds, Lecture Notes in Computer Science
**8285**:__13th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP'13__. Vietri sul Mare, Springer, Cham, 216-225. - Golovach, P., Paulusma, D. & Stewart, I.A. (2013), Graph editing to a fixed target, in Lecroq, T. & Mouchard, L. eds, Lecture Notes in Computer Science
**8288**:__International Workshop on Combinatorial Algorithms__. Rouen, France, Springer, Rouen, 192-205. - Xiang, Y., Stewart, I.A. & Madelaine, F.R. (2012), Node-to-node disjoint paths in k-ary n-cubes with faulty edges,
__17th International Conference on Parallel and Distributed Systems, ICPADS'11__. Tainan, Taiwan, IEEE Computer Society, Piscataway, 181-187. - Zhao, J., Xiang, Y., Dawson, L. & Stewart, I.A. (2011), Color image edge detection based on quantity of color information and implementation on the GPU, in Gonzalez, T. eds,
__23rd IASTED International Conference on Parallel and Distributed Computing and Systems, PDCS'11__. Dallas, USA, Acta Press, 116-123. - Stewart, I.A. (2011), Hamiltonian cycles through prescribed edges in k-ary n-cubes, in Wang, W., Zhu, X. & Du, D.-Z. eds, Lecture Notes in Computer Science Vol. 6831
**6831**:__5th Annual International Conference on Combinatorial Optimization and Applications, COCOA'11__. Zhangjiajie, China, Springer, Berlin, 82-97. - Gate, J. & Stewart. I.A. (2010), Frameworks for logically classifying polynomial-time optimisation problems, in Ablayev F. & Mayr E.F. eds, Lecture Notes in Computer Science
**6072**:__Proceedings of 5th International Computer Science Symposium in Russia__. Kazan, Russia, Springer-Verlag, Berlin, 120-131. - Stewart, I.A. (2010), A general algorithm for detecting faults under the comparison diagnosis model,
__24th IEEE International Parallel and Distributed Processing Symposium, IPDPS'10,__. Atlanta, Georgia, U.S.A., IEEE Computer Society Press, Piscataway, 1-9. - Xiang, Y. & Stewart, I.A. (2009), Pancyclicity in faulty k-ary 2-cubes,
__21st International Conference on Parallel and Distributed Computing and Systems, PDCS'09__. Cambridge, Massachusetts, USA, Acta Press, Cambridge MA 77-84. - Xiang, Y. & Stewart, I.A. (2009), Pancyclicity and panconnectivity in augmented k-ary n-cubes,
__The Fifteenth International Conference on Parallel and Distributed Systems (ICPADS'09)__. Shenzhen, China, IEEE Computer Society, Los Alamitos, 308-315. - Broersma, H., Johnson, M., Paulusma, D. & Stewart, I.A. (2006), The computational complexity of the parallel knock-out problem, Lecture Notes in Computer Science
**3887**:__7th Latin American Theoretical Informatics Symposium (LATIN 2006)__. Valdivia, Chile., Springer, Berlin, 250-261.

Conference Proceeding

Journal Article

- Stewart, I.A. (2020). Variational networks of cube-connected cycles are recursive cubes of rings.
*Information Processing Letters***157**: 105925. - Erickson, A., Navaridas, J. & Stewart, I.A. (2020). Relating the bisection width of dual-port, server-centric datacenter networks and the solution of edge-isoperimetric problems in graphs.
*Journal of Computer and System Sciences***108**: 10-28. - Stewart, I.A. (2020). Using semidirect products of groups to build classes of interconnection networks.
*Discrete Applied Mathematics***283**: 78-97. - Navaridas, Javier, Pascual, Jose A., Erickson, Alejandro, Stewart, Iain A. & Luján, Mikel (2019). INRFlow: An interconnection networks research flow-level simulation framework.
*Journal of Parallel and Distributed Computing***130**: 140-152. - Stewart, I.A. & Erickson, A. (2018). The influence of datacenter usage on symmetry in datacenter network design.
*The Journal of Supercomputing***74**(6): 2276-2313. - Golovach, P.A., Paulusma, D. & Stewart, I.A. (2017). Graph editing to a fixed target.
*Discrete Applied Mathematics***216**(Part 1): 181-190. - Stewart, I.A. (2017). Sufficient conditions for Hamiltonicity in multiswapped networks.
*Journal of Parallel and Distributed Computing***101**: 17-26. - Erickson, A., Stewart, I.A., Navaridas, J. & Kiasari, A.E. (2017). The stellar transformation: from interconnection networks to datacenter networks.
*Computer Networks***113**: 29-45. - Erickson, A., Stewart, I.A., Pascual, J.A. & Navaridas, J. (2017). Improved routing algorithms in the dual-port datacenter networks HCN and BCN.
*Future Generation Computer Systems***75**: 58-71. - Stewart, I.A. (2017). On the combinatorial design of data centre network topologies.
*Journal of Computer and System Sciences***89**: 328-348. - Kuo, C.-N. & Stewart, I.A. (2016). Edge-pancyclicity and edge-bipancyclicity of faulty folded hypercubes.
*Theoretical Computer Science***627**: 102-106. - Erickson, A., Kiasari, A.E., Navaridas, J. & Stewart, I.A. (2016). An Optimal Single-Path Routing Algorithm in the Datacenter Network DPillar.
*IEEE Transactions on Parallel and Distributed Systems***28**(3): 689-703. - Stewart, I.A. (2014). Interconnection networks of degree three obtained by pruning two-dimensional tori.
*IEEE Transactions on Computers***63**(10): 2473-2486. - Stewart, I.A. (2013). Multiswapped networks and their topological and algorithmic properties.
*Journal of Computer and System Sciences***79**(8): 1269-1286. - Gate, J. & Stewart, I.A. (2013). The expressibility of fragments of Hybrid Graph Logic on finite digraphs.
*Journal of Applied Logic***11**(3): 272-288. - Stewart, I.A. (2012). On the computational complexity of routing in faulty k-ary n-cubes and hypercubes.
*Parallel Processing Letters***22**(1): 1250003 - Stewart, I.A. (2012). A general technique to establish the asymptotic conditional diagnosability of interconnection networks.
*Theoretical Computer Science***452**: 132-147. - Xiang, Y. & Stewart, I.A. (2011). Augmented k-ary n-cubes.
*Information Sciences***181**(1): 239-256. - Xiang, Y. & Stewart, I.A. (2011). A multipath analysis of biswapped networks.
*The Computer Journal***54**(6): 920-930. - Xiang, Y. & Stewart, I.A. (2011). Bipancyclicity in k-ary n-cubes with faulty edges under a conditional fault assumption.
*IEEE Transactions on Parallel and Distributed Systems***22**(9): 1506-1513. - Lai, P.-L., Hsu, H.-C., Tsai, C.-H. & Stewart, I.A. (2010). A class of hierarchical graphs as topologies for interconnection networks.
*Theoretical Computer Science***411**(31-33): 2912-2924. - Stewart, I.A. & Xiang, Y. (2010). One-to-many node-disjoint paths in (n,k)-star graphs.
*Discrete Applied Mathematics***158**(1): 62-70. - Arratia-Quesada, A. & Stewart, I.A. (2009). On the power of deep pushdown stacks.
*Acta Informatica***46**(7): 509-531. - Stewart, I.A. (2009). Program schemes, queues, the recursive spectrum and zero-one laws.
*Fundamenta Informaticae***91**(2): 411-435. - Stewart, I.A. (2009). Logical and complexity-theoretic aspects of models of computation with restricted access to arrays.
*Journal of Logic and Computation***19**(1): 217-242. - Stewart, I.A. & Xiang, Y. (2009). Bipanconnectivity and bipancyclicity in k-ary n-cubes.
*IEEE Transactions on Parallel and Distributed Systems***20**(1): 25-33. - Stewart, I.A. (2008). On the fixed-parameter tractability of parameterized model-checking problems.
*Information Processing Letters***106**(1): 33-36. - Madelaine, F.R. & Stewart, I.A. (2008). Improved upper and lower bounds on the feedback vertex numbers of grids and butterflies.
*Discrete Mathematics***308**(18): 4144-4164. - Broersma, H., Johnson, M., Paulusma, D. & Stewart, I.A. (2008). The computational complexity of the parallel knock-out problem.
*Theoretical Computer Science***393**(1-3): 182-195. - Stewart, I.A. & Xiang, Y. (2008). Embedding long paths in k-ary n-cubes with faulty nodes and links.
*IEEE Transactions on Parallel and Distributed Systems***19**(8): 1071-1085. - Madelaine, F.R. & Stewart, I.A. (2007). Constraint satisfaction, logic and forbidden patterns.
*SIAM Journal of Computing***37**(1): 132-163. - Stewart, I.A. (2007). Distributed algorithms for building Hamiltonian cycles in k-ary n-cubes and hypercubes with faulty links.
*Journal of Interconnection Networks***8**(3): 253-284. - Gault, R.L. & Stewart, I.A. (2006). An infinite hierarchy in a class of polynomial-time program schemes.
*Theory of Computing Systems***39**(5): 753-783. - Feder, T., Madelaine, F.R. & Stewart, I.A. (2004). Dichotomies for classes of homomorphism problems involving unary functions.
*Theoretical Computer Science***314**(1-2): 1-43. - Stewart, I.A. (2003). The complexity of achievement and maintenance problems in agent-based systems.
*Artificial Intelligence***146**(2): 175-191. - Stewart, I.A. (2003). Using program schemes to capture polynomial-time logically on certain classes of structures.
*London Mathematical Society Journal of Computation and Mathematics***6**: 40-67. - Arratia, A.A. & Stewart, I.A. (2003). A note on first-order projections and games.
*Theoretical Computer Science***290**(3): 2085-2093. - Puricella, A. & Stewart, I.A. (2003). Greedy algorithms, H-colourings and a complexity-theoretic dichotomy.
*Theoretical Computer Science***290**(3): 1897-1913. - Madelaine, F.R. & Stewart, I.A. (2003). Some problems not definable using structure homomorphisms.
*Ars Combinatoria***67**: 153-159. - Stewart, I.A. (2002). Program schemes, arrays, Lindstroem quantifiers and zero-one laws.
*Theoretical Computer Science***275**(1-2): 283-310. - Ashir, Y.A. & Stewart, I.A. (2002). Fault-tolerant embeddings of Hamiltonian circuits in k-ary n-cubes.
*SIAM Journal On Discrete Mathematics***15**(3): 317-328. - Gault, R.L. & Stewart, I.A. (2001). On a hierarchy involving transitive closure logic and existential second-order quantification.
*Logic Journal of the IGPL***9**(6): 769-780. - Chauhan, S.R. & Stewart, I.A. (1999). On the power of built-in relations in certain classes of program schemes.
*Information Processing Letters***69**(2): 77-82. - Arratia-Quesada, A.A., Chauhan, S.R. & Stewart, I.A. (1999). Hierarchies in classes of program schemes.
*Journal of Logic and Computation***9**(6): 915-957.