Europe
Exploring Disease Interactions Using Markov Networks
Haaren, Jan Van (Katholieke Universiteit Leuven) | Davis, Jesse (Katholieke Universiteit Leuven) | Lappenschaar, Martijn (Radboud Universiteit Nijmegen) | Hommersom, Arjen (Radboud Universiteit Nijmegen)
Network medicine is an emerging paradigm for studying the co-occurrence between diseases. While diseases are often interlinked through complex patterns, most of the existing work in this area has focused on studying pairwise relationships between diseases. In this paper, we use a state-of-the-art Markov network learning method to learn interactions between musculoskeletal disorders and cardiovascular diseases and compare this to pairwise approaches. Our experimental results confirm that the sophisticated structure learner produces more accurate models, which can help reveal interesting patterns in the co-occurrence of diseases.
Exploring Disease Interactions Using Markov Networks
Haaren, Jan Van (Katholieke Universiteit Leuven) | Davis, Jesse (Katholieke Universiteit Leuven) | Lappenschaar, Martijn (Radboud Universiteit Nijmegen) | Hommersom, Arjen (Radboud Universiteit Nijmegen)
Network medicine is an emerging paradigm for studying the co-occurrence between diseases. While diseases are often interlinked through complex patterns, most of the existing work in this area has focused on studying pairwise relationships between diseases. In this paper, we use a state-of-the-art Markov network learning method to learn interactions between musculoskeletal disorders and cardiovascular diseases and compare this to pairwise approaches. Our experimental results confirm that the sophisticated structure learner produces more accurate models, which can help reveal interesting patterns in the co-occurrence of diseases.
Exploring Disease Interactions Using Markov Networks
Haaren, Jan Van (Katholieke Universiteit Leuven) | Davis, Jesse (Katholieke Universiteit Leuven) | Lappenschaar, Martijn (Radboud Universiteit Nijmegen) | Hommersom, Arjen (Radboud Universiteit Nijmegen)
Network medicine is an emerging paradigm for studying the co-occurrence between diseases. While diseases are often interlinked through complex patterns, most of the existing work in this area has focused on studying pairwise relationships between diseases. In this paper, we use a state-of-the-art Markov network learning method to learn interactions between musculoskeletal disorders and cardiovascular diseases and compare this to pairwise approaches. Our experimental results confirm that the sophisticated structure learner produces more accurate models, which can help reveal interesting patterns in the co-occurrence of diseases.
Exploring Disease Interactions Using Markov Networks
Haaren, Jan Van (Katholieke Universiteit Leuven) | Davis, Jesse (Katholieke Universiteit Leuven) | Lappenschaar, Martijn (Radboud Universiteit Nijmegen) | Hommersom, Arjen (Radboud Universiteit Nijmegen)
Network medicine is an emerging paradigm for studying the co-occurrence between diseases. While diseases are often interlinked through complex patterns, most of the existing work in this area has focused on studying pairwise relationships between diseases. In this paper, we use a state-of-the-art Markov network learning method to learn interactions between musculoskeletal disorders and cardiovascular diseases and compare this to pairwise approaches. Our experimental results confirm that the sophisticated structure learner produces more accurate models, which can help reveal interesting patterns in the co-occurrence of diseases.
Supporting Multiple Clinical Perspectives on a Patient-Centred Record Using Ontology Models
Chelsom, John James (City University, London) | Pande, Ira (Nottingham University Hospitals NHS Trust) | Gaywood, Ian (Nottingham University Hospitals NHS Trust)
Multi-disciplinary shared care is based around a single, patient-centred health record. A key driver for storing that record electronically is the need to gather data once (for clinical care) and to reuse it for secondary purposes, including clinical studies. However, physicians working in different specialties may have different perspectives on that record, both when entering new data for clinical use and when reusing those data in clinical studies. The ORCHID classification scheme in use at the Nottingham University Hospitals NHS Trust in the UK, is an ontology-based model which supports multiple, simultaneous clinical perspectives yet allows data to be stored as standard HL7 CDA documents in an immutable, patient-centred record. This paper describes the basic mechanisms used to support those multiple perspectives and the solution to specific problems of recording diagnosis with co-morbidities and recording different levels of detail in disease phenotypes.
On the Subexponential Time Complexity of CSP
Kanj, Iyad (DePaul University) | Szeider, Stefan (Vienna University of Technology)
A Constraint Satisfaction Problem (CSP) with n variables ranging over a domain of d values can be solved by brute-force in d^n steps (omitting a polynomial factor). With a more careful approach, this trivial upper bound can be improved for certain natural restrictions of the CSP. In this paper we establish theoretical limits to such improvements, and draw a detailed landscape of the subexponential-time complexity of CSP. We first establish relations between the subexponential-time complexity of CSP and that of other problems, including CNF-Sat. We exploit this connection to provide tight characterizations of the subexponential-time complexity of CSP under common assumptions in complexity theory. For several natural CSP parameters, we obtain threshold functions that precisely dictate the subexponential-time complexity of CSP with respect to the parameters under consideration. Our analysis provides fundamental results indicating whether and when one can significantly improve on the brute-force search approach for solving CSP.
Enforcing Meter in Finite-Length Markov Sequences
Roy, Pierre (Associate Researcher) | Pachet, Francois (Sony CSL Paris)
Markov processes are increasingly used to generate finite-length sequences that imitate a given style. However, Markov processes are notoriously difficult to control. Recently, Markov constraints have been introduced to give users some control on generated sequences. Markov constraints reformulate finite-length Markov sequence generation in the framework of constraint satisfaction (CSP). However, in practice, this approach is limited to local constraints and its performance is low for global constraints, such as cardinality or arithmetic constraints. This limitation prevents generated sequences to follow structural properties which are independent of the style, but inherent to the domain, such as meter. In this article, we introduce meter, a constraint that ensures a sequence is 1) Markovian with regards to a given corpus and 2) follows metrical rules expressed as cumulative cost functions. Additionally, meter can simultaneously enforce cardinality constraints. We propose a domain consistency algorithm whose complexity is pseudo-polynomial. This result is obtained thanks to a theorem on the growth of sumsets by Khovanskii. We illustrate our constraint on meter-constrained music generation problems that were so far not solvable by any other technique.
Algorithms for Strong Nash Equilibrium with More than Two Agents
Gatti, Nicola (Politecnico di Milano) | Rocco, Marco (Politecnico di Milano) | Sandholm, Tuomas (Carnegie Mellon University)
Strong Nash equilibrium (SNE) is an appealing solution concept when rational agents can form coalitions. A strategy profile is an SNE if no coalition of agents can benefit by deviating. We present the first general-purpose algorithms for SNE finding in games with more than two agents. An SNE must simultaneously be a Nash equilibrium (NE) and the optimal solution of multiple non-convex optimization problems. This makes even the derivation of necessary and sufficient mathematical equilibrium constraints difficult. We show that forcing an SNE to be resilient only to pure-strategy deviations by coalitions, unlike for NEs, is only a necessary condition here. Second, we show that the application of Karush-Kuhn-Tucker conditions leads to another set of necessary conditions that are not sufficient. Third, we show that forcing the Pareto efficiency of an SNE for each coalition with respect to coalition correlated strategies is sufficient but not necessary. We then develop a tree search algorithm for SNE finding. At each node, it calls an oracle to suggest a candidate SNE and then verifies the candidate. We show that our new necessary conditions can be leveraged to make the oracle more powerful. Experiments validate the overall approach and show that the new conditions significantly reduce search tree size compared to using NE conditions alone.
Extending STR to a Higher-Order Consistency
Lecoutre, Christophe (Université d'Artois) | Paparrizou, Anastasia (University of Western Macedonia) | Stergiou, Kostas (University of Western Macedonia)
One of the most widely studied classes of constraints in constraint programming (CP) is that of table constraints. Numerousspecialized filtering algorithms, enforcing the wellknown property called generalized arc consistency (GAC),have been developed for such constraints. Among the most successful GAC algorithms for table constraints, we find variants of simple tabular reduction (STR), like STR2. In this paper,we propose an extension of STR-based algorithms that achieves full pairwise consistency (FPWC), a consistency stronger than GAC and max restricted pairwise consistency (maxRPWC). Our approach involves counting the number of occurrences of specific combinations of values in constraint intersections. Importantly, the worst-case time complexity of one call to the basic filtering procedure at the heart of our new algorithm is quite close to that of STR algorithms. Experiments demonstrate that our method can outperform STR2 in many classes of problems, being significantly faster in some cases. Also, it is clearly superior to maxRPWC+, an algorithm that has been recently proposed.
Domain-Specific Heuristics in Answer Set Programming
Gebser, Martin (University of Potsdam) | Kaufmann, Benjamin (University of Potsdam) | Romero, Javier (University of Potsdam) | Otero, Ramón (University of Corunna) | Schaub, Torsten (University of Potsdam) | Wanko, Philipp (University of Potsdam)
We introduce a general declarative framework for incorporating domain-specific heuristics into ASP solving. We accomplish this by extending the first-order modeling language of ASP by a distinguished heuristic predicate. The resulting heuristic information is processed as an equitable part of the logic program and subsequently exploited by the solver when it comes to non-deterministically assigning a truth value to an atom. We implemented our approach as a dedicated heuristic in the ASP solver clasp and show its great prospect by an empirical evaluation.