57 resultados para formal verification


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Computer-based environments for supporting design are complex software artifacts. These tools need to use sound computational formalisms as well as address issues of human usability. The development of interactive and usable generative systems is a significant research area in design computation. Though classical search techniques play a central role in the generative kernels of these "closed-world" systems, the open-ended exploration of design spaces is the desirable goal. In this paper, we present a formal model of exploration that combines search with user driven exploration. We describe the role of interaction and agency in an experimental mixed-initiative design support system.

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This paper proposes a methodology for determining the shape and ultimately the functionality of objects from intensity images; 2D analytic functions are used to track 3D features during known camera motions. Three analytic functions are proposed that describe the relationship between pairs of points that are either stationary or moving depending on whether the points are on occluding boundaries or otherwise. Many of the problems of correspondence are reduced by using foveation, known camera motion, and active vision methods. The three analytic functions are shown to enable hypothesis refinement of the functionality of a number of 3D objects without full 3D information about the shape.

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This paper describes an investigation into the use of parametric 2D models describing the movement of edges for the determination of possible 3D shape and hence function of an object. An assumption of this research is that the camera can foveate and track particular features. It is argued that simple 2D analytic descriptions of the movement of edges can infer 3D shape while the camera is moved. This uses an advantage of foveation i.e. the problem becomes object centred. The problem of correspondence for numerous edge points is overcome by the use of a tree based representation for the competing hypotheses. Numerous hypothesis are maintained simultaneously and it does not rely on a single kinematic model which assumes constant velocity or acceleration. The numerous advantages of this strategy are described.

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Wire is a intermediate language to enable static program analysis on low level objects such as native executables. It has practical benefit in analysing the structure and semantics of malware, or for identifying software defects in closed source software. In this paper we describe how an executable program is disassembled and translated to the Wire intermediate language. We define the formal syntax and operational semantics of Wire and discuss our justifications for its language features. We use Wire in our previous work Malwise, a malware variant detection system. We also examine applications for when a formally defined intermediate language is given. Our results include showing the semantic equivalence between obfuscated and non obfuscated code samples. These examples stem from the obfuscations commonly used by malware.

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Average number of fiber-to-fiber contacts in a fibrous structure is a prerequisite to investigate the mechanical, optical and transport properties of stochastic nanomicrofibrous networks. In this research work, based on theoretical analysis presented for the estimation of the number of contacts between fibers in electrospun random multilayer nanofibrous assembles, experimental verification for theoretical dependence of fiber diameter and network porosity on the fiber to fiber contacts has been provided. The analytical model formulated is compared with the existing theories to predict the average number of fiber contacts of nanofiber structures. The effect of fiber diameters and network porosities on average number of fiber contacts of nano-microfiber mats has been investigated. A comparison is also made between the experimental and theoretical number of inter-fiber contacts of multilayer electrospun random nanomicrofibrous networks. It has been found that both the fiber diameter and the network porosity have significant effects on the properties of fiber-to-fiber contacts.

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Problem Statement: Over the past decade there has been an increasing global demand towards the integration of mobile technologies for teaching and learning. There has emerged a need for a survey instrument that can form a solid foundation for objective judgment of leaner perspectives as they begin using mobile applications for learning. The Mobile Learning Scale, a seven-item, Likert-type survey instrument, was developed by the authors in response to this need. Items were drawn from the key points developed for a 2011 paper by the authors on mobile learning prospects for informal learning in higher education [13], with many of these points initially developed during group discussions at the 2011 International Summit on ICT in Education hosted at UNESCO Headquarters, Paris, France. Approach: In order to access the performance of the instrument, data were gathered from 81 undergraduate and graduate university students during August and September of 2011. Follow-up data were also gathered from 19 undergraduates in February, 2012. Results: Initial indications are the instrument has good reliability (Alpha = .80 - .85) as well as acceptable content, construct, and criterion-related validity when used with its intended audience. Conclusions/Recommendations: The authors conclude that the Mobile Learning Scale v1.0 performs well as a unidimensional scale that is capable of assessing pre-post gains resulting from a mobile learning intervention within a university course. The authors propose that this new instrument should be useful for helping guide educators in the process of meaningful integration of Mobile Applications (Apps) into teaching and learning, inside and outside the classroom.

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Motion analysis of a parallel robot assisted minimally invasive surgery/microsurgery system (PRAMiSS) and the control structures enabling it to achieve milli/micromanipulations under the constraint of moving through a fixed penetration point or so-called remote centre-of-motion (RCM) are presented in this article. Two control algorithms are proposed suitable for minimally invasive surgery (MIS) with submillimeter accuracy and for minimally invasive micro-surgery (MIMS) with submicrometer accuracy. The RCM constraint is performed without having any mechanical constraint. Control algorithms also apply orientation constraint preventing the tip to orient relative to the soft tissues due to the robot movements. Experiments were conducted to verify accuracy and effectiveness of the proposed control algorithms for MIS and MIMS operations. The experimental results demonstrate accuracy and performance of the proposed position control algorithms.