Expert Systems
Computing Inconsistency Measurements under Multi-Valued Semantics by Partial Max-SAT Solvers
Xiao, Guohui (Institute of Information Systems, Vienna University of Technology) | Lin, Zuoquan (Department of Information Science, Peking University) | Ma, Yue (Laboratoire d’Informatique de l’universit´e Paris-Nord, Université Paris Nord) | Qi, Guilin (School of Computer Science and Engineering, Southeast University)
Measuring the inconsistency degree of a knowledge base can help us to deal with inconsistencies. Several inconsistency measures have been given under different multi-valued semantics, including 4-valued semantics, 3-valued semantics, LPm and Quasi Classical semantics. In this paper, we first carefully analyze the relationship between these inconsistency measures by showing that the inconsistency degrees under 4-valued semantics, 3-value semantics, LPm are the same, but different from the one based on Quasi Classical semantics. We then consider the computation of these inconsistency measures and show that computing inconsistency measurement under multi-valued semantics is usually intractable. To tackle this problem, we propose two novel algorithms that respectively encode the problems of computing inconsistency degrees under 4-valued semantics (3-valued semantics, LPm) and under Quasi Classical semantics into the partial Max-SAT problems. We implement these algorithms and do experiments on some benchmark data sets. The preliminary but encouraging experimental results show that our approach is efficient to handle large knowledge bases.
Finding Explanations of Inconsistency in Multi-Context Systems
Eiter, Thomas (Vienna University of Technology) | Fink, Michael (Vienna University of Technology) | Schüller, Peter (Vienna University of Technology) | Weinzierl, Antonius (Vienna University of Technology)
We provide two approaches for explaining inconsistency in multi-context systems, where decentralized and heterogeneous system parts interact via nonmonotonic bridge rules. Inconsistencies arise easily in such scenarios, and nonmonotonicity calls for specific methods of inconsistency analysis. Both our approaches characterize inconsistency in terms of involved bridge rules: either by pointing out rules which need to be altered for restoring consistency, or by finding combinations of rules which cause inconsistency. We show duality and modularity properties, give precise complexity characterizations, and provide algorithms for computation using HEX-programs. Our results form a basis for inconsistency management in heterogeneous knowledge integration systems.
On Building a Knowledge Base for Stability Theory
Rowinska-Schwarzweller, Agnieszka, Schwarzweller, Christoph
A lot of mathematical knowledge has been formalized and stored in repositories by now: different mathematical theorems and theories have been taken into consideration and included in mathematical repositories. Applications more distant from pure mathematics, however --- though based on these theories --- often need more detailed knowledge about the underlying theories. In this paper we present an example Mizar formalization from the area of electrical engineering focusing on stability theory which is based on complex analysis. We discuss what kind of special knowledge is necessary here and which amount of this knowledge is included in existing repositories.
Iterative Learning of Weighted Rule Sets for Greedy Search
Xu, Yuehua (Oregon State University) | Fern, Alan (Oregon State University) | Yoon, Sungwook (Palo Alto Research Center)
Greedy search is commonly used in an attempt to generate solutions quickly at the expense of completeness and optimality. In this work, we consider learning sets of weighted action-selection rules for guiding greedy search with application to automated planning. We make two primary contributions over prior work on learning for greedy search. First, we introduce weighted sets of action-selection rules as a new form of control knowledge for greedy search. Prior work has shown the utility of action-selection rules for greedy search, but has treated the rules as hard constraints, resulting in brittleness. Our weighted rule sets allow multiple rules to vote, helping to improve robustness to noisy rules. Second, we give a new iterative learning algorithm for learning weighted rule sets based on RankBoost, an efficient boosting algorithm for ranking. Each iteration considers the actual performance of the current rule set and directs learning based on the observed search errors. This is in contrast to most prior approaches, which learn control knowledge independently of the search process. Our empirical results have shown significant promise for this approach in a number of domains.
The Socceral Force
We are working to develop an expert system that can support decision making in European football (soccer). Based on the observation of players and coaches, it will be developed as an overlay system to our soccer simulation model. In theory, we are supposed to be able to take a comprehensive look at how the players behave in the field. There are already several (GPS and video based [Brillinger, 2009], [Pino et al., 2007], [Wisbey et al., 2009], [Barbero-Álvarez et al., 2010]) methods for this. But in case of coaches, to introduce computerization and automation seems to be a more difficult problem, however the behavior of the coaches may be simply analyzed by questionnaires.
Integrating User's Domain Knowledge with Association Rule Mining
This paper presents a variation of Apriori algorithm that includes the role of domain expert to guide and speed up the overall knowledge discovery task. Usually, the user is interested in finding relationships between certain attributes instead of the whole dataset. Moreover, he can help the mining algorithm to select the target database which in turn takes less time to find the desired association rules. Variants of the standard Apriori and Interactive Apriori algorithms have been run on artificial datasets. The results show that incorporating user's preference in selection of target attribute helps to search the association rules efficiently both in terms of space and time.
Using Linked Data for Semi-Automatic Guesstimation
Abourbih, Jonathan Alexander (University of Edinburgh) | Bundy, Alan (University of Edinburgh) | McNeill, Fiona (University of Edinburgh)
GORT is a system that combines Linked Data from across several Semantic Web data sources to solve guesstimation problems, with user assistance. The system uses customised inference rules over the relationships in the OpenCyc ontology, combined with data from DBPedia, to reason and perform its calculations. The system is extensible with new Linked Data, as it becomes available, and is capable of answering a small range of guesstimation questions.
Preprocessing Legal Text: Policy Parsing and Isomorphic Intermediate Representation
Waterman, K. Krasnow (Massachusetts Institute of Technology)
One of the most significant challenges in achieving digital privacy is incorporating privacy policy directly in computer systems. While rule systems have long existed, translating privacy laws, regulations, policies, and contracts into processor amenable forms is slow and difficult because the legal text is scattered, run-on, and unstructured, antithetical to the lean and logical forms of computer science. We are using and developing intermediate isomorphic forms as a Rosetta Stone-like tool to accelerate the translation process and in hopes of providing support to future domain-specific Natural Language Processing technology. This report describes our experience, thoughts about how to improve the form, and discoveries about the form and logic of the legal text that will affect the successful development of a rules tool to implement real-world complex privacy policies.
Embedded Rule-Based Reasoning for Digital Product Memories
Seitz, Christian (Siemens AG) | Lamparter, Steffen (Siemens AG) | Schoeler, Thorsten (Siemens AG) | Pirker, Michael (Siemens AG)
A Digital Product Memory provides a digital diary of the complete product life cycle that is embedded in the product itself using smart wireless sensor technology. The data is hereby gathered by recording relevant ambient parameters in digital form. In this paper, we present the architecture and cost-efficient implementation of an autonomous digital product memory that generates and interprets its diary using rule-based reasoning methods. As we assume an open, heterogeneous sensor infrastructure, we rely on standard syntax and semantics provided by the Web Ontology Language OWL. The digital product memory collects and provides data using the OWL fragment OWL2 RL which can be processed with standard rule engines. As rule engine we use CLIPS on embedded hardware and exemplify the application of the digital product memory e.g. for predictive maintenance.