Submodel Decomposition for Solving Limited Memory Influence Diagrams (Student Abstract)

This paper presents a systematic way of decomposing a limited memory influence diagram (LIMID) to a tree of single-stage decision problems, or submodels and solving it by message passing. The relevance in LIMIDs is formalized by the notion of the partial evaluation of the maximum expected utility, and the graph separation criteria for identifying submodels follow. The submodel decomposition provides a graphical model approach for updating the beliefs and propagating the conditional expected utilities for solving LIMIDs with the worst-case complexity bounded by the maximum treewidth of the individual submodels.

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Finding Small Proofs for Description Logic Entailments: Theory and Practice

10.29007/nhpp ◽

2020 ◽

Author(s):

Christian Alrabbaa ◽

Franz Baader ◽

Stefan Borgwardt ◽

Patrick Koopmann ◽

Alisa Kovtunova

Keyword(s):

Description Logic ◽

Theory And Practice ◽

Proof Complexity ◽

Reasoning Task ◽

Worst Case ◽

Derivation Step ◽

Worst Case Complexity ◽

Directed Hypergraphs ◽

The Individual ◽

Theoretical Side

Logic-based approaches to AI have the advantage that their behaviour can in principle be explained by providing their users with proofs for the derived consequences. However, if such proofs get very large, then it may be hard to understand a consequence even if the individual derivation steps are easy to comprehend. This motivates our interest in finding small proofs for Description Logic (DL) entailments. Instead of concentrating on a specific DL and proof calculus for this DL, we introduce a general framework in which proofs are represented as labeled, directed hypergraphs, where each hyperedge corresponds to a single sound derivation step. On the theoretical side, we investigate the complexity of deciding whether a certain consequence has a proof of size at most n along the following orthogonal dimensions: (i) the underlying proof system is polynomial or exponential; (ii) proofs may or may not reuse already derived consequences; and (iii) the number n is represented in unary or binary. We have determined the exact worst-case complexity of this decision problem for all but one of the possible combinations of these options. On the practical side, we have developed and implemented an approach for generating proofs for expressive DLs based on a non-standard reasoning task called forgetting. We have evaluated this approach on a set of realistic ontologies and compared the obtained proofs with proofs generated by the DL reasoner ELK, finding that forgetting-based proofs are often better w.r.t. different measures of proof complexity.

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Construction Method to the Extension Model of Influence Diagrams

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.268-270.88 ◽

2011 ◽

Vol 268-270 ◽

pp. 88-90

Author(s):

Qing Song Peng

Keyword(s):

Graphical Model ◽

Construction Method ◽

Influence Diagrams ◽

Influence Diagram ◽

New Model ◽

Extension Model

Influence diagram is a kind of graphical model that can represent both the probabilistic relationship between variables and can easy to make decisions. Extension model of Influence Diagrams is reviewed in this paper and the construction method of this new model is investigated.

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Generic Preferences over Subsets of Structured Objects

Journal of Artificial Intelligence Research ◽

10.1613/jair.2653 ◽

2009 ◽

Vol 34 ◽

pp. 133-164 ◽

Cited By ~ 3

Author(s):

M. Binshtok ◽

R. I. Brafman ◽

C. Domshlak ◽

S. E. Shiomony

Keyword(s):

Empirical Evaluation ◽

Efficient Manner ◽

Worst Case ◽

Case Complexity ◽

Optimal Subset ◽

Online Newspaper ◽

Worst Case Complexity ◽

Structured Objects ◽

The Individual ◽

Preference Specification

Various tasks in decision making and decision support systems require selecting a preferred subset of a given set of items. Here we focus on problems where the individual items are described using a set of characterizing attributes, and a generic preference specification is required, that is, a specification that can work with an arbitrary set of items. For example, preferences over the content of an online newspaper should have this form: At each viewing, the newspaper contains a subset of the set of articles currently available. Our preference specification over this subset should be provided offline, but we should be able to use it to select a subset of any currently available set of articles, e.g., based on their tags. We present a general approach for lifting formalisms for specifying preferences over objects with multiple attributes into ones that specify preferences over subsets of such objects. We also show how we can compute an optimal subset given such a specification in a relatively efficient manner. We provide an empirical evaluation of the approach as well as some worst-case complexity results.

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Extension Model of Influence Diagrams

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.55-57.1479 ◽

2011 ◽

Vol 55-57 ◽

pp. 1479-1482 ◽

Cited By ~ 3

Author(s):

Qing Song Peng

Keyword(s):

Supply Chain ◽

Supply Chain Management ◽

Bayesian Network ◽

Graphical Model ◽

Influence Diagrams ◽

Influence Diagram ◽

Chain Management ◽

New Model ◽

Extension Model ◽

Extensional Model

An influence diagram is a kind of graphical model that can represent both the probabilistic relationship between variables and can easy to make decisions. It can make full use of Bayesian Network and Decisiton Tree. Influence Diagram should be modify to inprove the effiency to express relationships among variables. Extensional model of Influence Diagrams is introduced in this paper to express the new kind influence diagrams. And this kind of new model can be applied in the area of supply chain management.

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Heuristic Optimization of Overloading Due to Electric Vehicles in a Low Voltage Grid

Energies ◽

10.3390/en13226069 ◽

2020 ◽

Vol 13 (22) ◽

pp. 6069

Author(s):

Sajjad Haider ◽

Peter Schegner

Keyword(s):

Electric Vehicles ◽

Low Voltage ◽

Optimization Methods ◽

Monte Carlo Analysis ◽

Heuristic Optimization ◽

Optimization Approach ◽

Worst Case ◽

Voltage Drops ◽

The Individual ◽

Nodal Voltage

It is important to understand the effect of increasing electric vehicles (EV) penetrations on the existing electricity transmission infrastructure and to find ways to mitigate it. While, the easiest solution is to opt for equipment upgrades, the potential for reducing overloading, in terms of voltage drops, and line loading by way of optimization of the locations at which EVs can charge, is significant. To investigate this, a heuristic optimization approach is proposed to optimize EV charging locations within one feeder, while minimizing nodal voltage drops, cable loading and overall cable losses. The optimization approach is compared to typical unoptimized results of a monte-carlo analysis. The results show a reduction in peak line loading in a typical benchmark 0.4 kV by up to 10%. Further results show an increase in voltage available at different nodes by up to 7 V in the worst case and 1.5 V on average. Optimization for a reduction in transmission losses shows insignificant savings for subsequent simulation. These optimization methods may allow for the introduction of spatial pricing across multiple nodes within a low voltage network, to allow for an electricity price for EVs independent of temporal pricing models already in place, to reflect the individual impact of EVs charging at different nodes across the network.

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Children’s Astronomy. Development of the Shape of the Earth Concept in Polish Children between 5 and 10 Years of Age

Education Sciences ◽

10.3390/educsci11020075 ◽

2021 ◽

Vol 11 (2) ◽

pp. 75

Author(s):

Jan Amos Jelinek

Keyword(s):

Mental Model ◽

Cultural Influences ◽

Test Results ◽

The Earth ◽

Spherical Earth ◽

The Individual ◽

High Level ◽

Cognitive Problems ◽

Teaching Situations ◽

Model Approach

The Earth’s shape concept develops as consecutive cognitive problems (e.g., the location of people and trees on the spherical Earth) are gradually resolved. Establishing the order of problem solving may be important for the organisation of teaching situations. This study attempted to determine the sequence of problems to be resolved based on tasks included in the EARTH2 test. The study covered a group of 444 children between 5 and 10 years of age. It captured the order in which children solve cognitive problems on the way to constructing a science-like concept. The test results were compared with previous studies. The importance of cultural influences connected to significant differences (24%) in test results was emphasised. Attention was drawn to the problem of the consistency of the mental model approach highlighted in the literature. The analysis of the individual sets of answers provided a high level of consistency of indications referring to the same model (36%), emphasising the importance of the concept of mental models.

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