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241.
Resource-Bounded Paraconsistent Inference   总被引:1,自引:0,他引:1  
In this paper, a new framework for reasoning from inconsistent propositional belief bases is presented. A family of resource-bounded paraconsistent inference relations is introduced. Such inference relations are based on S-3 entailment, an inference relation logically weaker than the classical one and parametrized by a set S of propositional variables. The computational complexity of our relations is identified, and their logical properties are analyzed. Among the strong features of our framework is the fact that tractability is ensured each time |S| is bounded and a limited amount of knowledge is taken into account within the belief base. Furthermore, binary connectives , behave in a classical manner. Finally, our framework is general enough to encompass several paraconsistent multi-valued logics (including S-3, J 3 and its restrictions), the standard coherence-based approach to inconsistency handling (based on the selection of consistent subbases) and some signed systems for paraconsistent reasoning as specific cases.  相似文献   
242.
Properly selected port sites for robot-assisted coronary artery bypass graft (CABG) improve the efficiency and quality of these procedures. In clinical practice, surgeons select port locations using external anatomic landmarks to estimate a patient's internal anatomy. This paper proposes an automated approach to port selection based on a preoperative image of the patient, thus avoiding the need to estimate internal anatomy. Using this image as input, port sites are chosen from a grid of surgeon-approved options by defining a performance measure for each possible port triad. This measure seeks to minimize the weighted squared deviation of the instrument and endoscope angles from their optimal orientations at each internal surgical site. This performance measure proves insensitive to perturbations in both its weighting factors and moderate intraoperative displacements of the patient's internal anatomy. A validation study of this port site selection was performed. cardiac algorithm also Six surgeons dissected model vessels using the port triad selected by this algorithm with performance compared to dissection using a surgeon-selected port triad and a port triad template described by Tabaie et al., 1999. With the algorithm-selected ports, dissection speed increased by up to 43% (p = 0.046) with less overall vessel trauma. Thus, this algorithmic approach to port site selection has important clinical implications for robot-assisted CABG which warrant further investigation.  相似文献   
243.
This paper introduces an algorithm for finding eukaryotic genes. It particularly addresses the problem of orphan genes, that is of genes that cannot, based on homology alone, be connected to any known gene family and to which it is therefore not possible to apply traditional gene finding methods. To the best of our knowledge, this is also the first algorithm that attempts to compare in an exact way two DNA sequences that contain both coding (i.e. exonic) and non-coding (i.e. intronic and, possibly, intergenic) parts. The comparison is performed following an algorithmical model of a gene that is as close as possible to the biological one (we consider in this paper the “one ORF, one gene” problem only). A gene is seen as a set of exons that are pieces of an assembly and are not independent. The algorithm is efficient enough: although the constants are higher than for usual sequence comparison, its time complexity is proportional to the product of the sequences lengths while its space complexity scales linearly with the length of the smallest sequence.  相似文献   
244.
This work deals with an implementation of automatic differentiation of C++ computer programs in forward mode using operator overloading and expression templates. We report on the efficiency of such implementation and its obvious advantage : the ability to perform sensitivity analysis without touching the source of the computer program by simply adding a library to it. We apply this tool to a flow control problem : minimize the drag of a cylinder, in subsonic unsteady turbulent flow, by controlling the boundary condition of the cylinder. Received: 1 June 1999 / Accepted: 29 May 2000  相似文献   
245.
A multiple objective grouping genetic algorithm for assembly line design   总被引:4,自引:0,他引:4  
The purpose of this paper is to describe some of the main problems concerning assembly line design. The focus will be on the following steps: (1) the input data preparation, (2) the elaboration of the logical layout of the line, which consists in the distribution of operations among stations along the line and an assignment of resources to the different stations, (3) finally the mapping phase using a simulation package to check the obtained results. This work presents a new method to tackle the hybrid assembly line design, dealing with multiple objectives. The goal is to minimize the total cost of the line by integrating design (station space, cost, etc.) and operation issues (cycle time, precedence constraints, availability, etc.). This paper also presents in detail a very promising approach to solve multiple objective problems. It is a multiple objective grouping genetic algorithm hybridized with the multicriteria decision-aid method PROMETHEE II. An approach to deal with users preferences in design problems is also introduced. The essential concepts adopted by the method are described and its application to an industrial case study is presented.  相似文献   
246.
In this work, RF MEMS continuous reversible variable inductor has been fabricated by using microelectronic technology and lamination process. We review, evaluate and compare this variable inductor with other work. The proposed inductor is a dual circular coil and has an inductance of few nH. The fundamental idea is to place a liquid droplet between the metal turns of a coil in order to modify the capacitive/resistive coupling between metal tracks and hence to change the stored magnetic energy. The SU-8 resin was used to realize the microfluidic channels and Au as metallic tracks. To prove the reversibility of the inductor, two cases were studied: filling and emptying of channels. The tuning range of the inductance is approximately 107 % at 1.6 GHz, making these devices very suitable as building blocks in many RF applications.  相似文献   
247.
Computing scattering rates of electrons and phonons stands at the core of studies of electron transport properties. In the high field regime, the interactions between all electron bands with all phonon bands need to be considered. This full band interaction implies a huge computational burden in calculating scattering rates. In this study, a new accelerated algorithm is presented for this task, which speeds up the computation by two orders of magnitude (100 times) and dramatically simplifies the coding. At the same time, it visually demonstrates the physical process of scattering more clearly.  相似文献   
248.
Valence-Driven Connectivity Encoding for 3D Meshes   总被引:13,自引:0,他引:13  
In this paper, we propose a valence-driven, single-resolution encoding technique for lossless compression of triangle mesh connectivity. Building upon a valence-based approach pioneered by Touma and Gotsman22 , we design a new valence-driven conquest for arbitrary meshes that always guarantees smaller compression rates than the original method. Furthermore, we provide a novel theoretical entropy study of our technique, hinting the optimality of the valence-driven approach. Finally, we demonstrate the practical efficiency of this approach (in agreement with the theoretical prediction) on a series of test meshes, resulting in the lowest compression ratios published so far, for both irregular and regular meshes, small or large.  相似文献   
249.
Module Checking   总被引:1,自引:0,他引:1  
In computer system design, we distinguish between closed and open systems. A closed system is a system whose behavior is completely determined by the state of the system. An open system is a system that interacts with its environment and whose behavior depends on this interaction. The ability of temporal logics to describe an ongoing interaction of a reactive program with its environment makes them particularly appropriate for the specification of open systems. Nevertheless, model-checking algorithms used for the verification of closed systems are not appropriate for the verification of open systems. Correct model checking of open systems should check the system with respect to arbitrary environments and should take into account uncertainty regarding the environment. This is not the case with current model-checking algorithms and tools. In this paper we introduce and examine the problem of model checking of open systems (module checking, for short). We show that while module checking and model checking coincide for the linear-time paradigm, module checking is much harder than model checking for the branching-time paradigm. We prove that the problem of module checking is EXPTIME-complete for specifications in CTL and 2EXPTIME-complete for specifications in CTL*. This bad news is also carried over when we consider the program-complexity of module checking. As good news, we show that for the commonly-used fragment of CTL (universal, possibly, and always possibly properties), current model-checking tools do work correctly, or can be easily adjusted to work correctly, with respect to both closed and open systems.  相似文献   
250.
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