• Article  

      A Graph-Theoretic Approach to Default Logic 

      Dimopoulos, Yannis; Magirou, V. (1994)
      A network representation of propositional seminormal disjunction-free default theories is presented, leading to a graph-theoretic approach to their analysis. The problem of finding an extension is proved to be equivalent ...
    • Conference Object  

      Heuristic guided optimization for propositional planning 

      Sideris, A.; Dimopoulos, Yannis (AAAI press, 2014)
      Planning as Satisfiability is an important approach to Propositional Planning. A serious drawback of the method is its limited scalability, as the instances that arise from large planning problems are often too hard for ...
    • Article  

      Ignoring irrelevant facts and operators in plan generation 

      Nebel, B.; Dimopoulos, Yannis; Koehler, J. (1997)
      It is traditional wisdom that one should start from the goals when generating a plan in order to focus the plan generation process on potentially relevant actions. The graphplan system, however, which is the most efficient ...
    • Conference Object  

      Integer programs and valid inequalities for planning problems 

      Bockmayr, A.; Dimopoulos, Yannis (Springer Verlag, 2000)
      Part of the recent work in AI planning is concerned with the development of algorithms that regard planning as a combinato-rial search problem. The underlying representation language is basically propositional logic. While ...
    • Conference Object  

      Integrating explanatory and descriptive learning in ILP 

      Dimopoulos, Yannis; Dzeroski, S.; Kakas, Antonis C. (1997)
      A learning framework that combines the two frameworks of explanatory and descriptive Inductive Logic Programming (ILP) is presented. The induced hypotheses in this framework are pairs of the form (T, IC) where T is a ...
    • Article  

      Learning non-monotonic logic programs: Learning exceptions 

      Dimopoulos, Yannis; Kakas, Antonis C. (1995)
      In this paper we present a framework for learning non-monotonic logic programs. The method is parametric on a classical learning algorithm whose generated rules are to be understood as default rules. This means that these ...
    • Conference Object  

      Making decisions through preference-based argumentation 

      Amgoud, L.; Dimopoulos, Yannis; Moraïtis, Pavlos (2008)
      Decision making is usually based on the comparative evaluation of different alternatives by means of a decision criterion. The whole decision process is compacted into a criterion formula on the basis of which alternatives ...
    • Conference Object  

      Multi-agent coordination and cooperation through classical planning 

      Dimopoulos, Yannis; Moraïtis, Pavlos (2007)
      Multi-agent planning is a fundamental problem in multiagent systems that has acquired a variety of meanings in the relative literature. In this paper we focus on a setting where multiple agents with complementary capabilities ...
    • Conference Object  

      A new look at the semantics and optimization methods of CP-networks 

      Brafman, R. I.; Dimopoulos, Yannis (2003)
      Preference elicitation is a serious bottleneck in many decision support applications and agent specification tasks. CP-nets were designed to make the preference elicitation process simpler and more intuitive for lay users ...
    • Article  

      On computing logic programs 

      Dimopoulos, Yannis (1996)
      In this paper we present and compare some classical problem-solving methods for computing the stable models of logic programs with negation. Using a graph theoretic representation of logic programs and their stable models, ...
    • Article  

      On kernels, defaults and even graphs 

      Dimopoulos, Yannis; Magirou, V.; Papadimitriou, C. H. (1997)
      Extensions in prerequisite-free, disjunction-free default theories have been shown to be in direct correspondence with kernels of directed graphs
    • Article  

      On the computational complexity of assumption-based argumentation for default reasoning 

      Dimopoulos, Yannis; Nebel, B.; Toni, F. (2002)
      Bondarenko et al. have recently proposed an abstract framework for default reasoning. Besides capturing most existing formalisms and proving that their standard semantics all coincide, the framework extends these formalisms ...
    • Article  

      On the semantics of inheritance networks 

      Dimopoulos, Yannis (1992)
      A semantics for inheritance reasoning is presented which allows both strict and defeasible knowledge to be represented. The approach proposed considers the semantics as consisting of two parts: the content theory which ...
    • Article  

      plasp 3: Towards Effective ASP Planning 

      Dimopoulos, Yannis; Gebser, Martin; Lühne, Patrick; Romero, Javier; Schaub, Torsten (2019)
      We describe the new version of the Planning Domain Definition Language (PDDL)-to-Answer Set Programming (ASP) translator plasp. First, it widens the range of accepted PDDL features. Second, it contains novel planning ...
    • Article  

      Plasp 3: Towards effective ASP planning 

      Dimopoulos, Yannis; Gebser, M.; Lühne, P.; Romero, J.; Schaub, T. (2017)
      We describe the new version of the PDDL-to-ASP translator plasp. First, it widens the range of accepted PDDL features. Second, it contains novel planning encodings, some inspired by SAT planning and others exploiting ASP ...
    • Conference Object  

      Preferred arguments are harder to compute than stable extensions 

      Dimopoulos, Yannis; Nebel, B.; Toni, F. (1999)
      Based on an abstract framework for nonmonotonic reasoning, Bondarenko et at. have extended the logic programming semantics of admissible and preferred arguments to other nonmonotonic formalisms such as circumscription, ...
    • Article  

      Propagation in CSP and SAT 

      Dimopoulos, Yannis; Stergiou, K. (2006)
      Constraint Satisfaction Problems and Prepositional Satisfiability, are frameworks widely used to represent and solve combinatorial problems. A concept of primary importance in both frameworks is that of constraint propagation. ...
    • Article  

      Propositional planning as optimization 

      Sideris, A.; Dimopoulos, Yannis (2012)
      Planning as Satisfiability is a most successful approach to optimal propositional planning. Although optimality is highly desirable, for large problems it comes at a high, often prohibitive, computational cost. This paper ...
    • Conference Object  

      Reasoning about actions and change in answer set programming 

      Dimopoulos, Yannis; Kakas, Antonis C.; Michael, Loizos (Springer Verlag, 2004)
      This paper studies computational issues related to the problem of reasoning about actions and change (RAC) by exploiting its link with the Answer Set Programming paradigm. It investigates how increasing the expressiveness ...
    • Article  

      Some theoretical results on the relationship between argumentation and coherence theory 

      Dimopoulos, Yannis; Moraïtis, Pavlos; Sierra, C. (2017)
      This work provides initial results on the relationship between argumentation and Paul Thagard’s coherence theory. We study the relationship, via appropriate transformations, between different types of coherent graphs ...