38425768
The Logic of Only Knowing as a Unified Framework for Non-Monotonic Reasoning
We propose to use the logic of only knowing (OL) by Levesque [6] as a unified framework that encompasses various non-monotonic formalisms and logic programming. OL is a modal logic which can be used to formalize an agent's introspective reasoning and to answer epistemic queries to databases. The OL logic allows one to formally express the statement “α is all I know” (in symbols, Oα) and to perform inferencing based on only-knowing, which is very useful for commonsense reasoning. Another nice thing about the OL logic is that it has a clear model-theoretic semantics and a simple proof theory, which is sound for the quantificational case, and both sound and complete for the prepositional case.
27866706
A New Method of Circumscribing Beliefs: The Propositional Case
We propose here a new notion of a minimal model for forming circumscription in belief-logic by incorporating the notion of minimal models in the prepositional logic. This results in a new circumscription operation for belief-formulas than the one considered in [4-6]. An important feature of the new circumscription operation is its close relationship with the circumscription of prepositional formulas. For instance, we have CIRC[Bp] = B(CIRC[p]), where p is a prepositional formula. We give several examples to show that the new notion of circumscription fits quite well with intuition.
14245135
Automatic Correlation and Calibration of Noisy Sensor Readings Using Elite Genetic Algorithms
This paper explores an image processing application of optimization techniques which entails interpreting noisy sensor data. The application is a generalization of image correlation; we attempt to find the optimal gruence which matches two overlapping gray scale images corrupted with noise. Both tabu search and genetic algorithms are used to find the parameters which match the two images. A genetic algorithm approach using an elitist reproduction scheme is found to provide significantly superior results.
31224210
The strong semantics for logic programs
Recently, the well-founded semantics of a logic programP has been strengthened to the well-founded semantics-by-case (WFC) and this in turn has been strengthened to the extended well-founded semantics (WFE). Both WFC(P) and WFE(P) have thelogical consequence property, namely, if an atomAj is true in the theory Th(P), thenAj is true in the semantics as well. However, neither WFC nor WFE has the GCWA property, i.e., if an atomAj is false in all minimal models ofP,Aj may not be false in WFC(P) (resp. WFE(P)). We extend the ideas in WFC and WFE to define a strong well-founded semantics WFS which has the GCWA property. The strong semantics WFS(P) is defined by combining GCWA with the notion ofderived rules. Here we use a new Type-III derived rules in addition to those used in WFC and WFE. The relationship between WFS and WFC is also clarified.
38658502
Learning by Discovering Problem Solving Heuristics Through Experience
The authors present a system, called SAFE (strategy acquisition from experience), which incorporates novel methods for discovering domain-dependent problem-solving heuristics. SAFE is implemented as a sorting system whose sorting strategies are represented as production rules. SAFE initially uses the insertion sort strategy to solve problems. After solving each given problem. SAFE learns symbolic rules from the solution path which is obtained by applying the existing heuristic information. By one or several processes of learning. SAFE is able to obtain the heuristics to sort new problems with minimum exchanges of elements. The notion of shortcut, an effective inductive learning bias for reducing the hypothesis space to be searched during learning, is introduced. >
9144862
Rules and fuzzy rules in text: concept, extraction and usage
Several concepts and techniques have been imported from other disciplines such as Machine Learning and Artificial Intelligence to the field of textual data. In this paper, we focus on the concept of rule and the management of uncertainty in text applications. The different structures considered for the construction of the rules, the extraction of the knowledge base and the applications and usage of these rules are detailed. We include a review of the most relevant works of the different types of rules based on their representation and their application to most of the common tasks of Information Retrieval such as categorization, indexing and classification.
13891792
Constructing Task-Level Assembly Strategies in Robot Programming by Demonstration
Programming by demonstration (PbD) is a technique for programming robots that holds much promise in making robots more accessible to ordinary, non-technical users. However, a well-known difficulty with the method is that a human will often demonstrate the task to be programmed inconsistently or even erroneously, leading to the inclusion of what is essentially noise in the demonstration. A number of techniques exist in the literature for filtering out this type of noise; however, most focus on very low level control command details. In this paper, we propose a new, complementary direction of research. We take a “task-level” view of the demonstration, and note that noise can exist at this level also. We propose a framework, based on a hybrid dynamic system modeling approach, to select the most optimal, task-level execution strategies that were demonstrated. We apply our framework to a real household task of inserting the compressible spindle of a paper towel holder into its supports. We conduct experiments to show that significant improvements in robot performance of the task can be achieved by a PbD regime that includes our method.
34159049
Approximation algorithms for scheduling real-time jobs with multiple feasible intervals
Time-critical jobs in many real-time applications have multiple feasible intervals. Such a job is constrained to execute from start to completion in one of its feasible intervals. A job fails if the job remains incomplete at the end of the last feasible interval. Earlier works developed an optimal off-line algorithm to schedule all the jobs in a given job set and on-line heuristics to schedule the jobs in a best effort manner. This paper is concerned with how to find a schedule in which the number of jobs completed in one of their feasible intervals is maximized. We show that the maximization problem is $${\cal N}{\cal P}$$-hard for both non-preemptible and preemptible jobs. This paper develops two approximation algorithms for non-preemptible and preemptible jobs. When jobs are non-preemptible, Algorithm Least Earliest Completion Time First (LECF) is shown to have a 2-approximation factor; when jobs are preemptible, Algorithm Least Execution Time First (LEF) is proved being a 3-approximation algorithm. We show that our analysis for the two algorithms are tight. We also evaluate our algorithms by extensive simulations. Simulation results show that Algorithms LECF and LEF not only guarantee the approximation factors but also outperform other multiple feasible interval scheduling algorithms in average.
2913360
Dynamic verification of temporal constraints on-the-fly for workflow systems
Temporal verification is an important method to check the temporal correctness of workflow management systems (WfMSs). However, the current temporal verification is relatively independent of the workflow system environments. It does not pay sufficient attention to the interrelationship between the temporal verification at different stages, the mutual dependency between some temporal constraints, and the run-time checkpoint selection strategy, which hence hinders the incorporation and consistency between the temporal verification and the workflow system environments. In this paper, we effectively integrate the temporal verification at different stages and explore the dependency between some temporal constraints. In addition, we present a new effective runtime checkpoint selection strategy which dynamically selects appropriate checkpoints based on the activity completion duration. Furthermore, based on these analyses, we develop some new methods for more efficient temporal verification. These analyses and new methods help to eliminate the gap between the temporal verification and the workflow system environments.
46388294
Soft Sorting in Logic Programming
Integrating sorts (types) into logic programming languages increases their expressiveness and evaluation efficiency. The sort structures usually considered are strict, in the sense that whenever an expression has a subexpression which is not properly sorted, the expression is classified as ill-sorted, and in effect is regarded as meaningless. Typically a logic programming language with strict sorting is incomplete, in the sense that some intuitively meaningful programs and queries are ill-sorted and hence are not part of the language.
6544638
Guaranteeing 2-manifold property for meshes
Meshes are the most commonly used objects in computer graphics. They generalize polyhedra by using non-planar faces. Modeling 2D manifold meshes with a simple user interface is an important problem in computer-aided geometric design. In this paper, we propose a conceptual framework for mesh modeling systems that guarantees topologically correct 2D manifolds. Our solution is based on graph rotation systems developed in topological graph theory. As an internal representation of meshes, we use a doubly-linked face list (DLFL). We have also developed a visual representation of the topology that provides a powerful tool for developing a user interface to manipulate the topology of the mesh.