control of a gas-turbine engine requires management of continuous and discrete (state-event) behaviour. A design environment- the Development Framework, is used to define both the continuous and discrete aspects of a ...
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control of a gas-turbine engine requires management of continuous and discrete (state-event) behaviour. A design environment- the Development Framework, is used to define both the continuous and discrete aspects of a turbine engine controller. The approach uses purpose-built software translation tools to capture the system's specification from commercial simulation tools. A unified design model based on a data flow notation, comprising both continuous and state-event behaviour is automatically generated. Specification and design models of selected gas-turbine engine controller subsystems are presented. The complexity of the application suggests that the approach can be used for industrial scale projects.
Embedded systems are computer-based systems which must respond to external stimuli within time scales determined by the external environment. Such systems are required to achieve ever more demanding behavioural. perfo...
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Embedded systems are computer-based systems which must respond to external stimuli within time scales determined by the external environment. Such systems are required to achieve ever more demanding behavioural. performance and safety requirements. Embedded systems are found in applications such as primary flight control, gas-turbine engine control and railway traffic management Often complex embedded systems are distributed, typically to achieve demanding performance or dependability requirements, and must operate within hard real-time constraints. Considerable effort is required to select optimal design solutions and ensure adherence to specified requirements. In embedded systems safety, reliability and response-times are considered as strict constraints on the system design. Achievement of these constraints requires meticulous analysis, typically through the use of specialist modelling and simulation techniques. Integration of knowledge and understanding obtained from disparate detailed models remains a considerable challenge. Ideally, a system which has both continuous dynamics and event-driven parts. would be modelled in one environment, using the most appropriate techniques for each part, and allowing the analysis of the whole system to be carried out simultaneously. The paper presents an integrated approach in order to translate automatically the information manipulated during the different phases of the design: specification. analysis, design and implementation.
Builds on the previous work by the authors (1998) by defining local versions of cross-positivity for vector fields, especially as related to shifted cones. The paper also furthers the development of a stability theory...
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Builds on the previous work by the authors (1998) by defining local versions of cross-positivity for vector fields, especially as related to shifted cones. The paper also furthers the development of a stability theory by introducing preliminary concepts of directed stability. The motivation is to apply this theory to analyzing the control of certain directionally constrained models, such as those found in materials processing.
When an unknown object with Lambertian reflectance is viewed orthographically, there is an implicit ambiguity in determining its 3-d structure: we show that the object's visible surface f(x, y) is indistinguishabl...
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When an unknown object with Lambertian reflectance is viewed orthographically, there is an implicit ambiguity in determining its 3-d structure: we show that the object's visible surface f(x, y) is indistinguishable from a `generalized bas-relief' transformation of the object's geometry, f¯(x, y) = λf(x, y)+μx+vy, and a corresponding transformation on the object's albedo. For each image of the object illuminated by an arbitrary number of distant light sources, there exists an identical image of the transformed object illuminated by similarly transformed light sources. This result holds both for the illuminated regions of the object as well as those in cast and attached shadows. Furthermore, neither small motion of the object, nor of the viewer will resolve the ambiguity in determining the flattening (or scaling) λ of the object's surface. Implications of this ambiguity on structure recovery and shape representation are discussed.
In computer vision, texture plays an important role. In this work we propose five human perceptual texture features heuristically extracted. Since a modeling can not be obtained from these features, we use a discrimin...
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We give an algorithm for the single-stage maximization criterion to attain multichannel blind deconvolution. This criterion determines the coefficients of equalizers for all channels simultaneously. However, the origi...
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We give an algorithm for the single-stage maximization criterion to attain multichannel blind deconvolution. This criterion determines the coefficients of equalizers for all channels simultaneously. However, the original maximization criterion has many constrains so that it is difficult to directly implement it as a numerical algorithm. By exploiting pre-whitening and lattice representations of paraunitary systems, we can reduce the original maximization problem into a simple constraint-free one and then present a stochastic gradient algorithm.
The implementation of road trains consisting of multiple hooked semi-trailers presents mechanical realization and traffic related problems. Among these problems, the most basic is the off-tracking problem. This paper ...
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The implementation of road trains consisting of multiple hooked semi-trailers presents mechanical realization and traffic related problems. Among these problems, the most basic is the off-tracking problem. This paper proposes a solution based on a kingpin sliding technique, that allows articulated semi-trailers to follow exactly the tractor's path. Simulation results showed that, for highway paths, the off-tracking deviation is completely eliminated.
Today more than ever efforts of governments and companies try to provide safe and efficient transportation through air, over water and on land. Current highway transportation systems, except of the intelligent and aut...
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Today more than ever efforts of governments and companies try to provide safe and efficient transportation through air, over water and on land. Current highway transportation systems, except of the intelligent and automated aspect, do not present any other significant development especially concerning the "truck vehicle". This paper proposes the idea of long truck-trains with multiple semi-trailers as highway vehicle systems for freight transportation. The basic mechanical characteristics of the truck-train are described and the corresponding steering problems are introduced. The paper states also the path following problem and includes a discussion of the various traffic and steering rules that must be applied when a truck-train travels on a multi-lane highway.
For very large document collections or high volume streams of documents, finding relevant documents is a major information filtering problem. A major aid to information retrieval systems produces a word frequency meas...
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