In this paper, an image segmentation method is proposed that integrates fuzzy 2-partition into Yen's maximum correlation thresholding method. A fuzzy 2-partition of the image is obtained by transforming the image ...
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In this paper, an image segmentation method is proposed that integrates fuzzy 2-partition into Yen's maximum correlation thresholding method. A fuzzy 2-partition of the image is obtained by transforming the image into fuzzy domain by means of two parameterized membership functions. Fuzzy correlation is defined to measure the appropriateness of the fuzzy 2-partition. An ideal threshold is calculated from the optimal membership functions' parameters, which make the corresponding fuzzy 2-partition have maximum fuzzy correlation. In the process of searching the optimal parameters of membership functions, a fast recursive algorithm is presented in order to reduce the computation complexity. Experimental results on synthetic image, brain magnetic resonance (MR) images and casting images show that the proposed method has a satisfactory performance. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.
The behaviour of the FracRoot model, which describes coarse-root architecture based on proximal root diameters using a recursive algorithm, was studied using field data on Populus deltoides Bartr. ex Marsh. in a short...
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The behaviour of the FracRoot model, which describes coarse-root architecture based on proximal root diameters using a recursive algorithm, was studied using field data on Populus deltoides Bartr. ex Marsh. in a short-rotation plantation. Roots were described as a branching, hierarchical network of connected links. Diameters of daughter links were estimated from the diameter of the mother link using scaling parameter p and allocation parameter q, which were based on sharing of the root cross-sectional area by daughter links. Parameters were estimated from complete root excavations. The length of each link and the vertical and horizontal branching angle distributions were recorded. Parameter p values were distributed log-normally, and q values followed a beta distribution both for the whole root system and within 5 mm link diameter classes. Including the variability of p and q in the model did not significantly improve root length estimates compared with the use of mean p and q values over all branching points. Including a coarse-root turnover factor based on field-observed evidence on root mortality improved the model fit to field data. Root length was more sensitive to parameter values and turnover factor than root mass. Field observations and the importance of the turnover factor to simulation accuracy suggest that coarse-root turnover should be considered in root research, at least under conditions of strong competition or other external stress.
We prove that every countable relation on the enumeration degrees, E, is uniformly definable from parameters in E. Consequently, the first order theory of E is recursively isomorphic to the second order theory of arit...
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We prove that every countable relation on the enumeration degrees, E, is uniformly definable from parameters in E. Consequently, the first order theory of E is recursively isomorphic to the second order theory of arithmetic. By an effective version of coding lemma, we show that the first order theory of the enumeration degrees of the Sigma(2)(0) sets is not decidable.
Modeling of vehicle behavior based on the identification method has received a renewed attention in recent years. In order to improve the linear time-invariant vehicle identification model, a more general identifiable...
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Modeling of vehicle behavior based on the identification method has received a renewed attention in recent years. In order to improve the linear time-invariant vehicle identification model, a more general identifiable vehicle model structure is proposed, in which time-varying characteristics of vehicle speed and cornering stiffness are taken into consideration. To identify the proposed linear time-varying vehicle model, a well-established data-driven method, named recursive optimized version of predictor-based subspace identification, is introduced. Before vehicle model identification, the influences of four parameters in the subspace algorithm are studied based on pulse input road test. And then a set of practical optimal parameters are chosen and used for the vehicle model identification. Through a series of standard road tests under different maneuvers, the linear time-varying vehicle model can be identified in real-time. It is demonstrated by comparison that the predicted outputs of the proposed vehicle model are much closer to the real vehicle outputs and the model has a wider range of application.
This paper considers parameter identification problems for the observability canonical state space systems, and a state observer based recursive least squares identification algorithm and a Kalman filter based least s...
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This paper considers parameter identification problems for the observability canonical state space systems, and a state observer based recursive least squares identification algorithm and a Kalman filter based least squares iterative identification algorithm are proposed for estimating the system parameters and states. A numerical example is provided to confirm the effectiveness of the proposed algorithms. (C) 2014 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
We propose a new recursion algorithm which is applicable to the electronic structure calculations of disordered materials using a non-orthogonal basis (NOB) set. This recursion approach is based on matrix algebra (mod...
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We propose a new recursion algorithm which is applicable to the electronic structure calculations of disordered materials using a non-orthogonal basis (NOB) set. This recursion approach is based on matrix algebra (modified Householder method) and takes central cluster states as 'initial states' of the calculation of the electronic Green functions. Some example calculations on the electronic density of states (DOS) of regular lattices are presented to demonstrate the applicability of the present method. It is shown that the NOB cluster recursion method is stable in numerical computations and practically does not produce any spurious or unphysical structures both for the site diagonal and intersite Green functions.
Efficient simulation of dynamical systems becomes more and more important in industry and research. Dynamic modeling of multi-body systems yields highly nonlinear equations of motion. Usually, the accelerations are co...
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Efficient simulation of dynamical systems becomes more and more important in industry and research. Dynamic modeling of multi-body systems yields highly nonlinear equations of motion. Usually, the accelerations are computed by an explicit inversion of the mass matrix that has the dimension according to the degrees of freedom. This classical foregoing implies high computational effort. In the present contribution, an O(n) formulation is introduced for efficient (recursive) procedure. It is based on the Projection Equation in subsystem representation, structuring the problem into parts and yielding interpretable intermediate solutions. The hereby necessary inversion refers to a reduced mass matrix that has the order of the considered subsystem. Additional constraints like endpoint contact are included via corresponding constraint forces. Avoiding an inversion of the total mass matrix is again successfully applied by a recursive procedure. The impact that occurs in the transition phase between the free system and constrained system is also solved in this sense. Results for the simulation of a plane pendulum motion with changing contact scenarios are presented.
Invariant-based programming is a correct-by-construction programming methodology in which programs are expressed as graphs of situations connected by transitions. Such graphs are called invariant diagrams. The situati...
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Invariant-based programming is a correct-by-construction programming methodology in which programs are expressed as graphs of situations connected by transitions. Such graphs are called invariant diagrams. The situations correspond to the pre- and postconditions and loop invariants of the program, while the transitions correspond to the program statements. The situations are developed before the transitions, and each transition is verified at the time it is added to the diagram. The correctness conditions for the transitions are derived using Hoare-like rules. In this paper, we present an embedding of invariant diagrams in the higher-order logic framework Isabelle/HOL for both proving the verification conditions in the Isabelle proof assistant, as well as generating code that is operationally consistent with the verification semantics by constructing a proof that the generated code is correct with respect to the situations of the invariant diagram. We describe a mechanic translation of the transitions of an invariant diagram into a collection of mutually recursive functions and an associated correctness theorem stating that the value computed by the functions satisfies the final situation. We show that the proofs of the correctness theorem and the well-foundedness of the recursive functions can be built mechanically. The verification conditions are lemmas in the proofs. The collection of recursive functions is a refinement of the original invariant diagram, and is in a form that can be directly converted to executable code by Isabelle. This allows proof-producing compilation of invariant diagrams into any of the languages supported by Isabelle code generator. We illustrate our approach with a case study, and show that full proof automation can be achieved. This work is a step towards verified compilation of invariant diagrams. (C) 2013 Elsevier Inc. All rights reserved.
The work deals with the programmed system of MOCODISS (Modeling of Continuous-Discrete Systems) that permits calculating and designing rod systems on the elastic base. The mathematical model is presented that describe...
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The work deals with the programmed system of MOCODISS (Modeling of Continuous-Discrete Systems) that permits calculating and designing rod systems on the elastic base. The mathematical model is presented that describes the dynamics of elastically attached rods with associated masses on the inhomogeneous base. Principal functional possibilities and the field of application of the programmed MOCODISS package are considered. The application is shown of the package to the problem of lateral oscillations of the rod system with elastic joints on the elastic step base.
The paper presents a survey of methods for constructing covering arrays used in generation of tests for interfaces with a great number of parameters. The application domain of these methods and algorithms used in them...
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The paper presents a survey of methods for constructing covering arrays used in generation of tests for interfaces with a great number of parameters. The application domain of these methods and algorithms used in them are analyzed. Specific characteristics of the methods, including time complexity and estimates of the required memory, are presented. Various-direct, recursive, optimization, genetic, and backtracking-algorithms used for constructing covering arrays are presented. Heuristics are presented that allow one to reduce arrays without loss of completeness, and application domains of these heuristics are outlined.
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