scholarly journals Preference-Based Inconsistency Management in Multi-Context Systems

2017 ◽  
Vol 60 ◽  
pp. 347-424 ◽  
Author(s):  
Thomas Eiter ◽  
Antonius Weinzierl
Keyword(s):  
Information Exchange ◽  
Complexity Analysis ◽  
Knowledge Bases ◽  
Preference Ordering ◽  
Generic Level ◽  
Worst Case ◽  
Preference Information ◽  
Inconsistency Management ◽  
Preference Orders ◽  
Selection Of

Multi-Context Systems (MCS) are a powerful framework for interlinking possibly heterogeneous, autonomous knowledge bases, where information can be exchanged among knowledge bases by designated bridge rules with negation as failure. An acknowledged issue with MCS is inconsistency that arises due to the information exchange. To remedy this problem, inconsistency removal has been proposed in terms of repairs, which modify bridge rules based on suitable notions for diagnosis of inconsistency. In general, multiple diagnoses and repairs do exist; this leaves the user, who arguably may oversee the inconsistency removal, with the task of selecting some repair among all possible ones. To aid in this regard, we extend the MCS framework with preference information for diagnoses, such that undesired diagnoses are filtered out and diagnoses that are most preferred according to a preference ordering are selected. We consider preference information at a generic level and develop meta-reasoning techniques on diagnoses in MCS that can be exploited to reduce preference-based selection of diagnoses to computing ordinary subset-minimal diagnoses in an extended MCS. We describe two meta-reasoning encodings for preference orders: the first is conceptually simple but may incur an exponential blowup. The second is increasing only linearly in size and based on duplicating the original MCS. The latter requires nondeterministic guessing if a subset-minimal among all most preferred diagnoses should be computed. However, a complexity analysis of diagnoses shows that this is worst-case optimal, and that in general, preferred diagnoses have the same complexity as subset-minimal ordinary diagnoses. Furthermore, (subset-minimal) filtered diagnoses and (subset-minimal) ordinary diagnoses also have the same complexity.

scholarly journals Preference-Based Inconsistency Management in Multi-Context Systems (Extended Abstract)

2018 ◽  
Author(s):  
Thomas Eiter ◽  
Antonius Weinzierl
Keyword(s):  
Computational Complexity ◽  
Information Flow ◽  
Information Exchange ◽  
Expressive Power ◽  
Case Finding ◽  
Base Case ◽  
Knowledge Based Systems ◽  
Worst Case ◽  
Knowledge Based ◽  
Inconsistency Management

Establishing information exchange between existing knowledge-based systems can lead to devastating inconsistency. Automatic resolution of inconsistency often is unsatisfactory, because any modification of the information flow may lead to bad or even dangerous conclusions. Methods to identify and select preferred repairs of inconsistency are thus needed. In this work, we leverage the expressive power and generality of Multi-Context Systems (MCS), a formalism for information exchange, to select most preferred repairs, by use of a meta-reasoning transformation. As for computational complexity, finding preferred repairs is not higher than the base case; finding most-preferred repairs is higher, yet worst-case optimal.

scholarly journals Selection of Optimal Magnets for Traction Motors to Prevent Demagnetization

Machines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 124
Author(s):  
Dantam Rao ◽  
Madhan Bagianathan
Keyword(s):  
Flux Density ◽  
Electric Vehicles ◽  
Parallel Line ◽  
Low Grade ◽  
Lower Grade ◽  
Worst Case ◽  
Traction Motors ◽  
Knee Point ◽  
Point Of Intersection ◽  
Selection Of

Currently, permanent-magnet-type traction motors drive most electric vehicles. However, the potential demagnetization of magnets in these motors limits the performance of an electric vehicle. It is well known that during severe duty, the magnets are demagnetized if they operate beyond a ‘knee point’ in the B(H) curve. We show herein that the classic knee point definition can degrade a magnet by up to 4 grades. To prevent consequent excessive loss in performance, this paper defines the knee point k as the point of intersection of the B(H) curve and a parallel line that limits the reduction in its residual flux density to 1%. We show that operating above such a knee point will not be demagnetizing the magnets. It will also prevent a magnet from degenerating to a lower grade. The flux density at such a knee point, termed demag flux density, characterizes the onset of demagnetization. It rightly reflects the value of a magnet, so can be used as a basis to price the magnets. Including such knee points in the purchase specifications also helps avoid the penalty of getting the performance of a low-grade magnet out of a high-grade magnet. It also facilitates an accurate demagnetization analysis of traction motors in the worst-case conditions.

scholarly journals Querying and Repairing Inconsistent Prioritized Knowledge Bases: Complexity Analysis and Links with Abstract Argumentation

2020 ◽  
Author(s):  
Meghyn Bienvenu ◽  
Camille Bourgaux
Keyword(s):  
Complexity Analysis ◽  
Knowledge Bases ◽  
Data Complexity ◽  
The Core ◽  
Inconsistency Handling ◽  
Definition Of ◽  
Priority Relation ◽  
Inconsistent Database ◽  
The Relationship ◽  
Computational Properties

In this paper, we explore the issue of inconsistency handling over prioritized knowledge bases (KBs), which consist of an ontology, a set of facts, and a priority relation between conflicting facts. In the database setting, a closely related scenario has been studied and led to the definition of three different notions of optimal repairs (global, Pareto, and completion) of a prioritized inconsistent database. After transferring the notions of globally-, Pareto- and completion-optimal repairs to our setting, we study the data complexity of the core reasoning tasks: query entailment under inconsistency-tolerant semantics based upon optimal repairs, existence of a unique optimal repair, and enumeration of all optimal repairs. Our results provide a nearly complete picture of the data complexity of these tasks for ontologies formulated in common DL-Lite dialects. The second contribution of our work is to clarify the relationship between optimal repairs and different notions of extensions for (set-based) argumentation frameworks. Among our results, we show that Pareto-optimal repairs correspond precisely to stable extensions (and often also to preferred extensions), and we propose a novel semantics for prioritized KBs which is inspired by grounded extensions and enjoys favourable computational properties. Our study also yields some results of independent interest concerning preference-based argumentation frameworks.

Efficient Policy-Based Inconsistency Management in Relational Knowledge Bases

2010 ◽  
pp. 264-277 ◽  
Author(s):  
Maria Vanina Martinez ◽  
Francesco Parisi ◽  
Andrea Pugliese ◽  
Gerardo I. Simari ◽  
V. S. Subrahmanian
Keyword(s):  
Knowledge Bases ◽  
Relational Knowledge ◽  
Inconsistency Management

Application of Variational Geometry to the Analysis of Mechanical Tolerances

1989 ◽  
Author(s):  
P. M. Martino ◽  
G. A. Gabriele
Keyword(s):  
Mechanical Design ◽  
Worst Case Analysis ◽  
Prototype System ◽  
Tolerance Design ◽  
Worst Case ◽  
Geometric Tolerances ◽  
Solid Models ◽  
The Cost ◽  
Selection Of

Abstract The proper selection of tolerances is an important part of mechanical design that can have a significant impact on the cost and quality of the final product. Yet, despite their importance, current techniques for tolerance design are rather primitive and often based on experience and trial and error. Better tolerance design methods have been proposed but are seldom used because of the difficulty in formulating the necessary design equations for practical problems. In this paper we propose a technique for the automatic formulation of the design equations, or design functions, which is based on the use of solid models and variational geometry. A prototype system has been developed which can model conventional and statistical tolernaces, and a limited set of geometric tolerances. The prototype system is limited to the modeling of single parts, but can perform both a worst case analysis and a statistical analysis. Results on several simple parts with known characteristics are presented which demonstrate the accuracy of the system and the types of analysis it can perform. The paper concludes with a discussion of extensions to the prototype system to a broader range of geometry and the handling of assemblies.

A Multiple-Domain Matrix Support to Capture Rationale for Engineering Design Changes

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
L. Siddharth ◽  
Prabir Sarkar
Keyword(s):  
Building Blocks ◽  
Knowledge Bases ◽  
Change Propagation ◽  
Design Environment ◽  
Web Based ◽  
Design Change ◽  
Design Changes ◽  
System 2 ◽  
Multiple Domain ◽  
Selection Of

Design changes are necessary to sustain the product against competition. Due to technical, social, and financial constraints, an organization can only implement a few of many change alternatives. Hence, a wise selection of a change alternative is fundamentally influential for the growth of the organization. Organizations lack knowledge bases to effectively capture rationale for a design change; i.e., identifying the potential effects a design change. In this paper, (1) we propose a knowledge base called multiple-domain matrix that comprises the relationships among different parameters that are building blocks of a product and its manufacturing system. (2) Using the indirect change propagation method, we capture these relationships to identify the potential effects of a design change. (3) We propose a cost-based metric called change propagation impact (CPI) to quantify the effects that are captured from the multiple-domain matrix. These individual pieces of work are integrated into a web-based tool called Vatram. The tool is deployed in a design environment to evaluate its usefulness and usability.

scholarly journals Multi-Valued Neutrosophic Distance-Based QUALIFLEX Method for Treatment Selection

Information ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 327
Author(s):  
Juan-Juan Peng ◽  
Chao Tian
Keyword(s):  
Distance Measure ◽  
Comparison Method ◽  
Decision Makers ◽  
Partial Ordering ◽  
Comparison Analysis ◽  
Neutrosophic Sets ◽  
Preference Information ◽  
Medical Diagnostic ◽  
Distance Difference ◽  
Selection Of

Multi-valued neutrosophic sets (MVNSs) consider the truth-membership, indeterminacy-membership, and falsity-membership simultaneously, which can more accurately express the preference information of decision-makers. In this paper, the normalized multi-valued neutrosophic distance measure is developed firstly and the corresponding properties are investigated as well. Secondly, the normalized multi-valued neutrosophic distance difference is defined and the corresponding partial ordering relation is discussed. Thirdly, based on the developed distances and comparison method, an extended multi-valued neutrosophic QUALItative FLEXible multiple criteria (QUALIFLEX) method is proposed to handle MCDM problems where the weights of criteria are completely unknown. Finally, an example for selection of medical diagnostic plan is provided to demonstrate the proposed method, together with sensitivity analysis and comparison analysis.

Propulsion Dynamic Requirements Analysis for Multi-Axle Skid-Steer Wheeled Vehicles

2020 ◽  
Author(s):  
Mostafa Yacoub ◽  
Ahmed Ali
Keyword(s):  
Experimental Validation ◽  
Worst Case ◽  
Wheeled Vehicle ◽  
Wheel Drive ◽  
System Requirements ◽  
Turning Radius ◽  
Four Wheel Drive ◽  
Driving Torque ◽  
Wheeled Vehicles ◽  
Selection Of

Abstract Multi-axle skid-steer wheeled vehicles have the advantages of simplicity and enhanced traction. That’s why they are used in off-road environments and also in mobile robots. In the present work, a dynamic analysis of the propulsion system requirements for multi-axle wheeled vehicles is investigated. As the multi-axle wheeled vehicle differentially steers at a smaller turning radius, the driving torque requirements approach their peak. The adhesion at each tire of the multi-axle vehicle and its relation to the contact patches are analyzed. The analysis presented starts with four wheel drive, six wheel drive and eight wheel drive vehicles, then it is widened to n-wheel drive vehicles. A generic formula for obtaining the propulsion torque requirements for multi-axle skid-steer wheeled vehicles is presented. The analysis is extended to include experimental validation of the obtained analytical results. The experimental work includes three small electrically driven skid-steer vehicles; four wheel drive vehicle, six wheel drive vehicle and eight wheel drive vehicle. The selection of the drive motors for each of those vehicles was based on the proposed formula. Each of the three vehicles was tested in the worst case adhesion torque requirement. The experimental results showed that the proposed formula is capable, to a great extent, to predict the torque requirements for the multi-axle skid-steer wheeled vehicles in the design phase.

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