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Nomenclatura Unesco > (11) Lógica

Mostrando recursos 141 - 160 de 136,008

141. Pedagogic challenges in Information Retrieval - teaching mathematics to Postgraduate Information Science Students - Andrew Macfarlane
Understanding of mathematics is needed to underpin the process of search, either explicitly with Exact Match (Boolean logic, adjacency) or implicitly with Best match natural language search. In this paper I outline some pedagogical challenges in teaching mathematics for information retrieval to postgraduate information science students. The aim is to take these challenges either found by experience or in the literature, to identify both theoretical and practical ideas in order to improve the delivery of the material and positively affect the learning of the target audience. Some ideas are put forward to resolve these issues and to promote discussion.

142. The Uses of Fuzzy Logic in Autonomous Robot Navigation: a catalogue raisonne
The development of techniques for autonomous navigation in real-world envi-ronments constitutes one of the major trends in the current research on robotics. An important problem in autonomous navigation is the need to cope with the large amount of uncertainty that is inherent of natural environments. Fuzzy logic has features that make it an adequate tool to address this problem. In this paper, we review some of the possible uses of fuzzy logic in the eld of au-tonomous navigation. We focus on four issues: how to design robust behavior-producing modules; how to coordinate the activity of several such modules; how to...

143. Separation Logic with First-Class Heaps and a New Frame Rule - Duc-hiep Chu; Joxan Jaffar
Separation Logic brought an advance to program verification of data structures through its use of (recursively defined) predicates to implicitly represent heaps, and the separation operator to construct heaps from disjoint subheaps. While this facilitated local reason-ing in program fragments, the consideration of subheaps that are disjoint meant that any form of sharing between predicates is prob-lematic and often requires manual proofs whose complexity may outweigh the core benefits of Separation Logic itself. With this as background motivation, we present an assertion language in which subheaps may be explicitly defined within predicates, and the effect of separation obtained by specifying...

144. An ID-logic formalization of the composition of autonomous databases - Bert Van Nuffelen; Ofer Arieli; Maurice Bruynooghe
Abstract. We introduce a declarative approach for a coherent composition of autonomous databases. For this we use ID-logic, a formalism that extends clas-sical logic with inductive definitions. We consider ID-logic theories that express, at the same time, the two basic challenges in database composition problems: relating different schemas of the local databases to one global schema (schema integration) and amalgamating the distributed and possibly contradictory data to one consistent database (data integration). We show that our framework supports different methods for schema integration (as well as their combinations) and that it provides a straightforward way of dealing with inconsistent data....

145. A FOLK THEOREM FOR COMPETING MECHANISMS - Michael Peters; Cristian; Troncoso Valverde; Universidad Diego; Portales Manuel Rodríguez
Abstract. We provide a partial characterization of the set of out-come functions that can be supported as perfect Bayesian equilib-rium in the recommendation game described in Yamashita (Econo-metrica 2010). We show that the set of outcome functions that can be supported is at least as large as the set supportable by a mech-anism designer in the sense of Myerson (Myerson 1979). We show how to support random and correlated outcomes as equilibrium outcomes in the recommendation game. Many outcome functions can typically be supported as equilibria in competing mechanism games. Some of these outcomes look quite ’collusive’. The reason for...

146. REVIEW ARTICLE Formal Verification of Concurrent Programs with Read-Write Locks - Ming Fu; Yu Zhang; Yong Li
Abstract Read-write locking is an important mecha-nism to improve concurrent granularity, but it is difficult to reason about the safety of concurrent programs with read-write locks. Concurrent Separation Logic(CSL) provides a simple but powerful technique for locally rea-soning about concurrent programs with mutual exclusive locks. Unfortunately, CSL cannot be directly applied to reason about concurrent programs with read-write locks due to the different concurrent control mechanisms. This paper focuses on extending CSL and present a proof-carrying code(PCC) system for reasoning about concurrent programs with read-write locks. We extend the heap model with a writing permission set, denoted as logical heap,...

147. GlitchLess: dynamic power minimization in FPGAs through edge alignment and glitch filtering - Julien Lamoureux; Guy G. F. Lemieux; Steven J. E. Wilton
nique for reducing power in field-programmable gate arrays (FPGAs) by eliminating unnecessary logic transitions called glitches. This is done by adding programmable delay elements to the logic blocks of the FPGA. After routing a circuit and performing static timing analysis, these delay elements are pro-grammed to align the arrival times of the inputs of each lookup table (LUT), thereby preventing new glitches from being gen-erated. Moreover, the delay elements also behave as filters that eliminate other glitches generated by upstream logic or off-chip circuitry. On average, the proposed implementation eliminates 87 % of the glitching, which reduces overall FPGA power...

148. Performance Assessment Of Fuzzy Logic Based Power System Stabilizer - S. M. Radaideh
Abstract:- This paper investigates the performance of fuzzy logic based power system stabilizer in damping the local modal oscillations of an interconnected power system. A comparative study between Mamdani and Sugeno fuzzy logic designs on one hand and conventional power system stabilizers on the other hand is presented. The results obtained by computer simulation show the superiority of fuzzy logic controllers over the conventional designs. The test results also show the effectiveness of Mamdani design relative to Sugeno design in damping the electromechanical mode of oscillation.

149. Ecological modernization as social theory - F. H. Buttel
In this paper I examine some of the reasons for and implications of the ascendance of ecological modernization thought. I stress that its rapid rise to prominence is not because it is a well-developed and highly-codified social theory, but rather because it accords particularly well with a number of intellectual and broader political–economic factors, many of which lie outside the realms of sociology and environmental sociology. I suggest that while ecological modernization is indistinct as a social theory its basic logic suggests two points. First, the most sophisticated versions of ecological modernization revolve around the notion that political processes and...

We present a planar three-dimensional (3D) fracture growth simulator, based on a displacement discon-tinuity (DD) method for multi-layer elasticity problems. The method uses a 5xed mesh approach, with rectangular panel elements to represent the planar fracture surface. Special fracture tip logic is included that allows a tip element to be partially fractured in the tip region. The fracture perimeter is modelled in a piece-wise linear manner. The algorithm can model any number of interacting fractures that are restricted to lie on a single planar surface, located orthogonal to any number of parallel layers. The multiple layers are treated using a...

151. Fuzzy Aggregating Function for Multiobjective VLSI Placement - Junaid A. Khan; Sadiq M. Sait
Abstract- When fuzzy logic is used with mul-tiobjective optimization, min/max operators may not be desirable. This is primarily due to lack of compensation/submission of min/max. To over-come this, Ordered Weighted Averaging(OWA) operators were proposed by Yager. OWA re-quires the selection of a control parameter ¯, which is di®erent for di®erent problem instances. In this work we propose new fuzzy aggregating functions that simulate the fuzzy AND/OR logic, and have the advantages of OWA without a need of any control parameter. Comparison with OWA for the VLSI cell placement using Simulated Evo-lution produced encouraging results. I.

152. Programming Groups of Rational Agents - Michael Fisher; Chiara Ghidini; Benjamin Hirsch
Abstract. In this paper, we consider the problem of effectively pro-gramming groups of agents. These groups should capture structuring mechanisms common in multi-agent systems, such as teams, cooperative groups, and organisations. Not only should individual agents be dynamic and evolving, but the groups in which the agents occur must be open, flexible and capable of similar evolution and restructuring. We enable the description and implementation of such groups by providing an extension to our previous work on programming languages for agent-based systems based on executable temporal and modal logics. With such formalism as a basis, we consider the grouping aspects...

153. Updating Epistemic Logic Programs - Yan Zhang
We consider the problem of updating nonmonotonic knowledge bases represented by epistemic logic programs where disjunctive information and notions of knowledge and belief can be explicitly expressed. We propose a formulation for epistemic logic program update based on a principle called minimal change and maximal coherence. The central feature of our approach is that during an update or a sequence of updates, contradictory information is removed on a basis of minimal change under the seman-tics of epistemic logic programs and then coherent information is maximally retained in the update result. Through various update scenarios, we show that our approach provides...

154. 1A Wiki for Business Rules in Open Vocabulary, Executable English - Adrian Walker
The problem of business-IT alignment is of widespread economic concern. As one way of addressing the problem, this paper describes an online system that functions as a kind of Wiki-- one that supports the collaborative writing and running of business and scientific applications, as rules in open vocabulary, executable English, using a browser. Since the rules are in English, they are indexed by Google and other search engines. This is useful when looking for rules for a task that one has in mind. The design of the system integrates the semantics of data, with a semantics of an inference method,...

The concept of Geographic Automata System (GAS) formalizes an object-based view of city structure and functioning; OBEUS software implements this view on the operational level. The paper presents the basic components of the latest version of OBEUS, which is based on.NET technology and developed according to OODBMS logic. We claim that all urban Cellular Automata and Multi-Agent models we are aware of can be represented as GAS and implemented as OBEUS applications. GAS and OBEUS can thus serve as a universal framework for object-based urban simulations.

We describe a system of reversible grammar in which, given a logic-grammar specification of a natural anguage, two efficient PROLOG programs are derived by an off-line compilation process: a parser and a generator for this language. The centerpiece of the system is the inversion algorithm designed to compute the generator code from the parser's PRO-LOG code, using the collection of minimal sets of essential arguments (MSEA) for predicates. The sys-tem has been implemented to work with Definite Clause Grammars (DCG) and is a part of an English-Japanese machine translation project currently under development a NYU's Courant Insti-tute.

157. Playing Hybrid Games with KeYmaera? - Jan-david Quesel; Andre ́ Platzer
Abstract. We propose a new logic, called differential dynamic game logic (dDGL), that adds several game constructs on top of differential dynamic logic (dL) so that it can be used for hybrid games. The logic dDGL is a conservative extension of dL, which we exploit for our imple-mentation of dDGL in the theorem prover KeYmaera. We provide rules for extending the dL sequent proof calculus to handle the dDGL con-structs by identifying analogs to operators of dL. We have implemented dDGL in an extension of KeYmaera and verified a case study in which a robot satisfies a joint safety and...

158. n 20 Pin Molded Chip Carrier Package (ADC0838 only) n Surface-Mount Package - Key Specifications
converters with a serial I/O and configurable input multiplex-ers with up to 8 channels. The serial I/O is configured to comply with the NSC MICROWIRE ™ serial data exchange standard for easy interface to the COPS ™ family of proces-sors, and can interface with standard shift registers or µPs. The 2-, 4- or 8-channel multiplexers are software configured for single-ended or differential inputs as well as channel assignment. The differential analog voltage input allows increasing the common-mode rejection and offsetting the analog zero input voltage value. In addition, the voltage reference input can be adjusted to allow encoding any smaller...

159. Computational ontologies of parthood, componenthood, and containment - Thomas Bittner; Maureen Donnelly
Parthood, componenthood, and containment rela-tions are commonly assumed in biomedical ontolo-gies and terminology systems, but are not usually clearly distinguished from another. This paper con-tributes towards a unified theory of parthood, com-ponenthood, and containment relations. Our goal in this is to clarify distinctions between these relations as well as principles governing their interrelations. We first develop a theory of these relations in first order predicate logic and then discuss how descrip-tion logics can be used to capture some important aspects of the first order theory. 1

160. Cooperative query answering for RDF - Adrian Tanasescu; Liris Universite; Claude Bernard Lyon
Abstract. The interest of representing data for the Semantic Web has generated standards for expressing knowledge on the Web. RDF, as one of those standards, has become a recommendation of the W3C. Even if it was designed to be human and machine readable (XML encoding, triples, labeled graphs), RDF was not provided with querying and rea-soning services. Most work on querying RDF has concentrated on the use of logic programming evaluation techniques and SQL extensions. We take a new look at the problem of querying and reasoning on RDF statements and find that order-sorted feature (OSF) terms apply to this...


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