A new type of electromechanical total artificial heart (TAH) based on circular rolling-cylinder mechanism was developed to overcome critical problems in motor-driven artificial hearts such as large size and difficulti...
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A new type of electromechanical total artificial heart (TAH) based on circular rolling-cylinder mechanism was developed to overcome critical problems in motor-driven artificial hearts such as large size and difficulties in fitting the heart to atrial remnants and arterial vessels. Its performance and reliability were evaluated in mock circulation and in an animal implant experiment. The total weight and volume of the pump is 650 g and 600 mL, respectively. This new pump was implanted in a calf for total heart replacement and 96 h of survival was achieved. The whole system, including pump, controller, and control algorithm performed well enough to improve the prospect of eventual clinical application of our TAH system.
Bidirectional singleton arc consistency (BiSAC) which is an extended singleton arc consistency (SAC) has been proposed recently. The first contribution of this paper is to propose and prove two theorems of BiSAC theor...
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Bidirectional singleton arc consistency (BiSAC) which is an extended singleton arc consistency (SAC) has been proposed recently. The first contribution of this paper is to propose and prove two theorems of BiSAC theoretically (one is a property of BiSAC and the other is the property of allowing the deletion of some BiSAC-inconsistent values). Secondly, based on these properties we present two algorithms, denoted by BiSAC-DF and BiSAC-DP, to enforce BiSAC. Also, we prove their correctness and analyze the space and time complexity of them in detail. Besides, for special circumstances, we show that BiSAC-DF admits a worst-case time complexity in O(en(2)d(4)) and a best one in O(en(2)d(3)) when the problem is an already BiSAC, while BiSAC-DP also has the same best one when the tightness is small. Finally, experiments on a wide range of CSP instances show BiSAC-DF and BiSAC-DP are usually around one order of magnitude faster than the existing BiSAC-1. For some special instances, BiSAC-DP is about two orders of magnitude efficient.
A simple mutual exclusion algorithm is presented that only uses nonatomic shared variables of bounded size, and that satisfies bounded overtaking. When the shared variables behave atomically, it has the first-come-fir...
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A simple mutual exclusion algorithm is presented that only uses nonatomic shared variables of bounded size, and that satisfies bounded overtaking. When the shared variables behave atomically, it has the first-come-first-served property (FCFS). Nonatomic access makes information vulnerable. The effects of this can be mitigated by minimizing the information and by spreading it over more variables. The design approach adopted here begins with such mitigating efforts. These resulted in an algorithm with a proof of correctness, first for atomic variables. This proof is then used as a blueprint for the simultaneous development of the algorithm for nonatomic variables and its proof. Mutual exclusion is proved by means of invariants. Bounded overtaking and liveness under weak fairness are proved with invariants and variant functions. Liveness under weak fairness is formalized and proved in a set-theoretic version of temporal logic. All these assertions are verified with the proof assistant PVS. We heavily rely on the possibility offered by a proof assistant like PVS to reuse proofs developed for one context in a different context.
A method for performing numerical calculations of the thermo-electro-physical characteristics of an electricity generating channel with a complex geometry using the experimental databases developed at the Leipunskii I...
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A method for performing numerical calculations of the thermo-electro-physical characteristics of an electricity generating channel with a complex geometry using the experimental databases developed at the Leipunskii Institute for Physics and Power Engineering is described. The current-voltage characteristic of the electricity-generating channel is calculated in order to predict the electro-thermo-physical characteristics of new-generation space-craft thermionic nuclear power facilities. An analytical relation for determining the current-voltage characteristic of an electricity-generating element on the basis of the average temperature of the electrodes is derived;this relation can be used to compare the output characteristics of advanced thermionic nuclear power facilities. An iterative algorithm for calculating the parameters of the electricity-generating elements and the entire channel by the grid method is developed.
A new denoising algorithm is proposed according to the characteristics of hyperspectral remote sensing image (HRSI) in the curvelet domain. Firstly, each band of HRSI is transformed into the curvelet domain, and the s...
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A new denoising algorithm is proposed according to the characteristics of hyperspectral remote sensing image (HRSI) in the curvelet domain. Firstly, each band of HRSI is transformed into the curvelet domain, and the sets of subband images are obtained from different wavelength of HRSI. And then the detail subband images in the same scale and same direction from different wavelengths of HRSI are stacked to obtain new 3-D datacubes of the curvelet domain. Again, the characteristics analysis of these 3-D datacubes is performed. The analysis result shows that each new 3-D datacube has the strong spectral correlation. At last, due to the strong spectral correlation of new 3-D datacubes, the multiple linear regression is introduced to deal with these new 3-D datacubes in the curvelet domain. The simulated and the real data experiments are performed. The simulated data experimental results show that the proposed algorithm is superior to the compared algorithms in the references in terms of SNR. Furthermore, MSE and MSSIM in each band are utilized to show that the proposed algorithm is superior. The real data experimental results show that the proposed algorithm effectively removes the common spotty noise and the strip noise and simultaneously maintains more fine features during the denoising process.
In this paper, a novel kernel-based limited-view computed tomography (CT) reconstruction model is proposed. First based on the classical Feldkamp-Davis-Kress (FDK) algorithm, the reconstruction kernel is derived. Then...
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In this paper, a novel kernel-based limited-view computed tomography (CT) reconstruction model is proposed. First based on the classical Feldkamp-Davis-Kress (FDK) algorithm, the reconstruction kernel is derived. Then according to the improved approximate inverse for limited view reconstruction, the FDK kernel is truncated to be compact, after which the ring artifacts is reduced. Finally an anisotropic diffusion governed by the Chambolle-Lions equation is introduced to suppress the other artifacts and noise. In the Chambolle-Lions equation, a threshold function is proposed to separate the regions with high or few features adaptively. The efficiency and accuracy of the method are shown in several numerical experiments. (C) 2012 Elsevier Ltd. All rights reserved.
Hierarchical decompositions of graphs are interesting for algorithmic purposes, There are several types of hierarchical decompositions. Tree decompositions are the best known ones. On graphs of tree-width at most k, i...
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Hierarchical decompositions of graphs are interesting for algorithmic purposes, There are several types of hierarchical decompositions. Tree decompositions are the best known ones. On graphs of tree-width at most k, i.e., that have tree decompositions of width at most k, where k is fixed, every decision or optimization problem expressible in monadic second-order logic has a linear algorithm. We prove that this is also the case for graphs of clique-width at most k, where this complexity measure is associated with hierarchical decompositions of another type, and where logical formulas are no longer allowed to use edge set quantifications. We develop applications to several classes of graphs that include cographs and are, like cographs, defined by forbidding subgraphs with "too many" induced paths with four vertices.
We propose delegated tuning and forwarding (DTF), a new architecture for dynamically assigning wavelength channels in a ''broadcast star'' optical network. DTF exploits tunable components without makin...
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We propose delegated tuning and forwarding (DTF), a new architecture for dynamically assigning wavelength channels in a ''broadcast star'' optical network. DTF exploits tunable components without making excessive demands on tuner agility by combining the tuning on demand of receivers with the forwarding of packets over a logical topology. We describe the control algorithms of DTF and prove some results establishing their stability and robustness. We show by simulation that DTF achieves lower hop-counts in conditions of light-to-moderate load than do DeBruijn graph networks. When a DTF network is saturated, the average number of hops in each path is only about 10% higher than the average for a DeBruijn graph network, suggesting that, even under high loads, the evolution of network topology under DTF is close to optimal.
The critical external pressure stability calculation of stiffened penstock in the hydroelectric power station is very important work for penstock design. At present, different assumptions and boundary simplification a...
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The critical external pressure stability calculation of stiffened penstock in the hydroelectric power station is very important work for penstock design. At present, different assumptions and boundary simplification are adopted by different calculation methods which sometimes cause huge differences too. In this paper, we present an immune based artificial neural network model via the model and stability theory of elastic ring, we study effects of some factors (such as pipe diameter, pipe wall thickness, sectional size of stiffening ring, and spacing between stiffening rings) on penstock critical external pressure during huge thin-wall procedure of penstock. The results reveal that the variation of diameter and wall thickness can lead to sharp variation of penstock external pressure bearing capacity and then give the change interval of it. This paper presents an optimizing design method to optimize sectional size and spacing of stiffening rings and to determine penstock bearing capacity coordinate with the bearing capacity of stiffening rings and penstock external pressure stability coordinate with its strength safety. As a practical example, the simulation results illustrate that the method presented in this paper is available and can efficiently overcome inherent defects of BP neural network.
In this study, the author discusses a Pareto strategy implemented via state and static output feedback for a class of weakly coupled large-scale discrete-time stochastic systems with state-and control-dependent noise....
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In this study, the author discusses a Pareto strategy implemented via state and static output feedback for a class of weakly coupled large-scale discrete-time stochastic systems with state-and control-dependent noise. The asymptotic structure along with the uniqueness and positive semi-definiteness of the solutions of cross-coupled non-linear matrix equations (CNMEs) is newly established via the implicit function theorem. The main contribution of this study is the proposal of a parameter-independent local state and static output feedback Pareto strategy. Moreover, a computational approach for solving the CNMEs is also considered if the information about the small parameter is available. Particularly, a new iterative algorithm based on the linear matrix inequality is established to design a Pareto strategy. Finally, in order to demonstrate the effectiveness of the proposed design method, a numerical example is provided for practical aircraft control problems.
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