Inter-satellite links have characters of time-varying, unreliability and intermittent-connecting, so that applying the multi-path routing in the low earth orbit (LEO) satellite networks can make message disorder and m...
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Inter-satellite links have characters of time-varying, unreliability and intermittent-connecting, so that applying the multi-path routing in the low earth orbit (LEO) satellite networks can make message disorder and message loss. A multi-path routing scheme integrated with network coding was proposed to solve this problem. It is proved that with the same multi-path number and path message loss rate, the scheme outperforms the traditional multi-path routing in terms of message delivery rate. Moreover, the performances of both schemes were evaluated by the extended ns-2 software in terms of message delivery rate under the conditions of different multi-path numbers, link message loss rates and redundancy factors. The result validates the theory analysis and shows that the scheme can efficiently improve the reliability and save the onboard communication resources as well as enhance the error control of multi-path routing with certain ranges of message loss.
A numerical analysis of the steady/pulsatile flow and macromolecular (such as LDL and Albumin) transport in curved blood vessels was carried out. The computational results predict that the vortex of the secondary fl...
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A numerical analysis of the steady/pulsatile flow and macromolecular (such as LDL and Albumin) transport in curved blood vessels was carried out. The computational results predict that the vortex of the secondary flow is time-dependent in the aortic arch. The concentration of macromolecule concentrates at the region of sharp curve, and the wall concentration at the outer part is higher than that at the inner part. Atherosclerosis and thrombosis are prone to develop in such regions with sharp flow.
Recommendation system is one of the most important technologies applied in e-commerce. Similarity measuring method is fundamental to collaborative filtering algorithm, and traditional methods are inefficient especiall...
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Recommendation system is one of the most important technologies applied in e-commerce. Similarity measuring method is fundamental to collaborative filtering algorithm, and traditional methods are inefficient especially when the user rating data are extremely sparse. Based on the outstanding characteristics of Cloud Model on the process of transforming a qualitative concept to a set of quantitative numerical values, a novel similarity measuring method, namely the likeness comparing method based on cloud model (LICM) is proposed in this paper. LICM compares the similarity of two users on knowledge level, which can overcome the drawback of attributes' strictly matching. This work analysis traditional methods throughly and puts forward a novel collaborative filtering algorithm, which is based on the LICM method. Experiments on typical data set show the excellent performance of the present collaborative filtering algorithm based on LICM, even with extremely sparsity of data.
From point of view of physics, especially of mechanics, we briefly introduce fractional operators (with emphasis on fractional calculus and fractional differential equa- tions) used for describing intermediate process...
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From point of view of physics, especially of mechanics, we briefly introduce fractional operators (with emphasis on fractional calculus and fractional differential equa- tions) used for describing intermediate processes and critical phenomena in physics and mechanics, their progress in theory and methods and their applications to modern me- chanics. Some authors’ researches in this area in recent years are included. Finally, prospects and evaluation for this subject are made.
The experiments of lock release gravity currents were performed in a rectangular channel with salt water and fresh water. The spreading law of the salt water is validated by using a digital video to record the progres...
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In the high speed range, vector control of rotor flux orientation of an induction machine implements good perfornance. However, the perfornance in low speed rang deteriorates because of the inaccurate estimation of ro...
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ISBN:
(纸本)9623675445
In the high speed range, vector control of rotor flux orientation of an induction machine implements good perfornance. However, the perfornance in low speed rang deteriorates because of the inaccurate estimation of rotor flux and speed. In this paper, modified voltage model for rotor flux estimation and neuron model-reference adaptive system (MARS) for speed estimation are used to improve the perfornance of speed sensorless vector control. To improve the accuracy of rotor flux estimation, the stator resistance is identified on-line. The experimental results show that the proposed scheme yields improved perfornance in low speed range.
Near-equiatomic Ni-Ti alloys are known to exhibit shape memory effect associated with a B2↔B19' martensitic transformation. These alloys are often used in various cyclic modes in application, typically as actuator...
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Near-equiatomic Ni-Ti alloys are known to exhibit shape memory effect associated with a B2↔B19' martensitic transformation. These alloys are often used in various cyclic modes in application, typically as actuators and sensors. The B2↔B19' martensitic transformation in Ni-Ti is accompanied with a large lattice distortion. Cycling through this transformation, induced thermally, mechanically or by the combination of the two, is found to cause structural damage to the alloys, hence changes their functional properties. This study investigates the effect of transformation cycling and heat treatment on the property stability of near-equiatomic Ti-Ni. It was found that in the case of thermally induced transformation cycling, incomplete transformation cycles caused less structural damage to the matrix than full transformation cycles whereas in the case of mechanically induced transformation cycling via pseudoelasticity in tension, partial or full transformation cycling caused similar property changes. The indifference of the case of pseudoelastic cycling is attributed to the localisation of the deformation, commonly known as the Lüders-type deformation.
To found the suitable models to describe the behavior of biochemistry systems, the dynamic Ε -SVM method was proposed on the basis of SVM. Each training sample uses different error. The existed methods for selecting ...
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This paper reports an experimental study on the correlation between the deviation from Gaussianity of the probability density function (PDF) of a fluctuating scalar and the dependence of the scalar dissipation on the ...
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This paper reports an experimental study on the correlation between the deviation from Gaussianity of the probability density function (PDF) of a fluctuating scalar and the dependence of the scalar dissipation on the scalar itself in turbulent flows. The study demonstrates that the departure of the scalar PDF from Gaussianity reflects the degree to which the dissipation rate depends statistically on the scalar. Of important significance, present results obtained from wake and jet flows, together with those deduced from previous work on various turbulent flows, appear to point to a generic expression for the total correlation. This expression suggests that the analytical result of O’Brien and Jiang [Phys. Fluids A 3, 3121 (1991)], derived for homogeneous turbulence, should be also valid for inhomogeneous turbulence. That is, the statistical independence of the scalar dissipation and the scalar itself appears to act as the sufficient and necessary condition for the scalar PDF to be Gaussian in any stationary turbulence. It follows that the independence assumption, often used in combustion modeling, is reasonable only in the flow region where the scalar PDF is closely Gaussian.
The reduction approaches are presented for vibration control of symmetric, cyclic periodic and linking structures. The condensation of generalized coordinates, the locations of sensors and actuators, and the relation ...
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The reduction approaches are presented for vibration control of symmetric, cyclic periodic and linking structures. The condensation of generalized coordinates, the locations of sensors and actuators, and the relation between system inputs and control forces are assumed to be set in a symmetric way so that the control system posses the same repetition as the structure considered. By employing proper transformations of condensed generalized coordinates and the system inputs, the vibration control of an entire system can be implemented by carrying out the control of a number of sub-structures, and thus the dimension of the control problem can be significantly reduced.
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