Patrick Prosser

Last updated

Patrick Prosser
Prosser SandYacht Nov 2003 lzn.jpg
Prosser in 2003
Born (1952-09-08) 8 September 1952 (age 72)
Glasgow, Scotland
Nationality Scottish
Alma mater Strathclyde University
Known for Conflict-directed backjumping
Scientific career
Fields Constraint programming
Institutions University of Glasgow
Doctoral advisor Iain Buchanan

Patrick Prosser (born 8 September 1952) is a Computer Scientist who spent the bulk of his career at the University of Glasgow. His research has centred on constraint programming, although it has extended into the application of those techniques into other areas. For his major contributions to the theory and practice of constraint programming, Patrick was awarded the Association for Constraint Programming's Research Excellence Award on 15 September 2011: he is only the sixth recipient of this award. [1] He gave a prerecorded acceptance speech, which is available on YouTube. [2]

His most notable contribution is his invention of conflict-directed backjumping, an advanced technique for reducing search in constraint problems by avoiding unnecessary work on backtracking. His 1993 paper [3] describing this has been widely cited. [4]

Other areas of constraint programming he has researched include the identification of hard problems [5] and techniques for solving vehicle routing problems. [6] His interest in applications of constraint programming has included (for example) how it can be used in computing species trees. [7]

Amongst his recreations is kite flying as a founder of the Kite Club of Scotland. He has written about the Tetrahedral kite. [8]

Related Research Articles

<span class="mw-page-title-main">Search algorithm</span> Any algorithm which solves the search problem

In computer science, a search algorithm is an algorithm designed to solve a search problem. Search algorithms work to retrieve information stored within particular data structure, or calculated in the search space of a problem domain, with either discrete or continuous values.

<span class="mw-page-title-main">Mathematical optimization</span> Study of mathematical algorithms for optimization problems

Mathematical optimization or mathematical programming is the selection of a best element, with regard to some criteria, from some set of available alternatives. It is generally divided into two subfields: discrete optimization and continuous optimization. Optimization problems arise in all quantitative disciplines from computer science and engineering to operations research and economics, and the development of solution methods has been of interest in mathematics for centuries.

Constraint programming (CP) is a paradigm for solving combinatorial problems that draws on a wide range of techniques from artificial intelligence, computer science, and operations research. In constraint programming, users declaratively state the constraints on the feasible solutions for a set of decision variables. Constraints differ from the common primitives of imperative programming languages in that they do not specify a step or sequence of steps to execute, but rather the properties of a solution to be found. In addition to constraints, users also need to specify a method to solve these constraints. This typically draws upon standard methods like chronological backtracking and constraint propagation, but may use customized code like a problem-specific branching heuristic.

Constraint satisfaction problems (CSPs) are mathematical questions defined as a set of objects whose state must satisfy a number of constraints or limitations. CSPs represent the entities in a problem as a homogeneous collection of finite constraints over variables, which is solved by constraint satisfaction methods. CSPs are the subject of research in both artificial intelligence and operations research, since the regularity in their formulation provides a common basis to analyze and solve problems of many seemingly unrelated families. CSPs often exhibit high complexity, requiring a combination of heuristics and combinatorial search methods to be solved in a reasonable time. Constraint programming (CP) is the field of research that specifically focuses on tackling these kinds of problems. Additionally, the Boolean satisfiability problem (SAT), satisfiability modulo theories (SMT), mixed integer programming (MIP) and answer set programming (ASP) are all fields of research focusing on the resolution of particular forms of the constraint satisfaction problem.

In artificial intelligence, symbolic artificial intelligence is the term for the collection of all methods in artificial intelligence research that are based on high-level symbolic (human-readable) representations of problems, logic and search. Symbolic AI used tools such as logic programming, production rules, semantic nets and frames, and it developed applications such as knowledge-based systems, symbolic mathematics, automated theorem provers, ontologies, the semantic web, and automated planning and scheduling systems. The Symbolic AI paradigm led to seminal ideas in search, symbolic programming languages, agents, multi-agent systems, the semantic web, and the strengths and limitations of formal knowledge and reasoning systems.

In theoretical computer science, the subgraph isomorphism problem is a computational task in which two graphs G and H are given as input, and one must determine whether G contains a subgraph that is isomorphic to H. Subgraph isomorphism is a generalization of both the maximum clique problem and the problem of testing whether a graph contains a Hamiltonian cycle, and is therefore NP-complete. However certain other cases of subgraph isomorphism may be solved in polynomial time.

In artificial intelligence and operations research, constraint satisfaction is the process of finding a solution through a set of constraints that impose conditions that the variables must satisfy. A solution is therefore an assignment of values to the variables that satisfies all constraints—that is, a point in the feasible region.

Edward Tsang is a Computer Science professor at the University of Essex. He holds a first degree in Business Administration from the Chinese University of Hong Kong (1977), and an MSc and PhD in Computer Science from the University of Essex. Prior to his PhD studies, he served for five years in various positions in the commercial sector in Hong Kong.

Automated planning and scheduling, sometimes denoted as simply AI planning, is a branch of artificial intelligence that concerns the realization of strategies or action sequences, typically for execution by intelligent agents, autonomous robots and unmanned vehicles. Unlike classical control and classification problems, the solutions are complex and must be discovered and optimized in multidimensional space. Planning is also related to decision theory.

In computer science, a min-conflicts algorithm is a search algorithm or heuristic method to solve constraint satisfaction problems.

In mathematical optimization, constrained optimization is the process of optimizing an objective function with respect to some variables in the presence of constraints on those variables. The objective function is either a cost function or energy function, which is to be minimized, or a reward function or utility function, which is to be maximized. Constraints can be either hard constraints, which set conditions for the variables that are required to be satisfied, or soft constraints, which have some variable values that are penalized in the objective function if, and based on the extent that, the conditions on the variables are not satisfied.

Distributed constraint optimization is the distributed analogue to constraint optimization. A DCOP is a problem in which a group of agents must distributedly choose values for a set of variables such that the cost of a set of constraints over the variables is minimized.

Alan Mackworth is a professor emeritus in the Department of Computer Science at the University of British Columbia. He is known as "The Founding Father" of RoboCup. He is a former president of the Association for the Advancement of Artificial Intelligence (AAAI) and former Canada Research Chair in Artificial Intelligence from 2001 to 2014.

<span class="mw-page-title-main">Vehicle routing problem</span> Optimization problem

The vehicle routing problem (VRP) is a combinatorial optimization and integer programming problem which asks "What is the optimal set of routes for a fleet of vehicles to traverse in order to deliver to a given set of customers?" It generalises the travelling salesman problem (TSP). It first appeared in a paper by George Dantzig and John Ramser in 1959, in which the first algorithmic approach was written and was applied to petrol deliveries. Often, the context is that of delivering goods located at a central depot to customers who have placed orders for such goods. The objective of the VRP is to minimize the total route cost. In 1964, Clarke and Wright improved on Dantzig and Ramser's approach using an effective greedy algorithm called the savings algorithm.

Guided local search is a metaheuristic search method. A meta-heuristic method is a method that sits on top of a local search algorithm to change its behavior.

The constraint composite graph is a node-weighted undirected graph associated with a given combinatorial optimization problem posed as a weighted constraint satisfaction problem. Developed and introduced by Satish Kumar Thittamaranahalli, the idea of the constraint composite graph is a big step towards unifying different approaches for exploiting "structure" in weighted constraint satisfaction problems.

Knowledge-based configuration, also referred to as product configuration or product customization, is an activity of customising a product to meet the needs of a particular customer. The product in question may consist of mechanical parts, services, and software. Knowledge-based configuration is a major application area for artificial intelligence (AI), and it is based on modelling of the configurations in a manner that allows the utilisation of AI techniques for searching for a valid configuration to meet the needs of a particular customer.

The Zebra Puzzle is a well-known logic puzzle. Many versions of the puzzle exist, including a version published in Life International magazine on December 17, 1962. The March 25, 1963, issue of Life contained the solution and the names of several hundred successful solvers from around the world.

In information technology a reasoning system is a software system that generates conclusions from available knowledge using logical techniques such as deduction and induction. Reasoning systems play an important role in the implementation of artificial intelligence and knowledge-based systems.

Pascal Van Hentenryck is the A. Russell Chandler III Chair and Professor of Industrial and Systems Engineering at Georgia Tech. He is credited with pioneering advances in constraint programming and stochastic optimization, bridging theory and practice to solve real-world problems across a range of domains including sports scheduling, protein folding, kidney matching, disaster relief, power systems, recommender systems, and transportation. He has developed several optimization technologies including CHIP, Numerica, the Optimization Programming Language, and Comet. He has also published several books, including Online Stochastic Combinatorial Optimization, Hybrid Optimization, and Constraint-Based Local Search.

References

  1. Association for Constraint Programming's Research Excellence Award website. Archived 2 April 2012 at the Wayback Machine
  2. Patrick Prosser's video acceptance speech playlist on Youtube.
  3. Prosser, Patrick (1993). "Hybrid Algorithms for the Constraint Satisfaction Problem". Computational Intelligence. 9 (3): 268–299. doi:10.1111/j.1467-8640.1993.tb00310.x.
  4. Google Scholar search
  5. Prosser, Patrick (1996). "An empirical study of phase transitions in binary constraint satisfaction problems". Artificial Intelligence. 81 (1–2): 81–109. doi:10.1016/0004-3702(95)00048-8.
  6. Backer, Bruno De; Furnon, Vincent; Shaw, Paul; Kilby, Philip; Prosser, Patrick (2000). "Solving Vehicle Routing Problems Using Constraint Programming and Metaheuristics". Journal of Heuristics. 6 (4): 501–523. doi:10.1023/A:1009621410177. S2CID   15296616.
  7. N. C. A. Moore and P. Prosser (2008) "The Ultrametric Constraint and its Application to Phylogenetics", JAIR, Volume 32, pages 901-938
  8. The tetrahedral principle in kite design, revisited, Patrick Prosser, 1996.