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181.
This paper presents a full-scale solution to the detection of the traffic data using laser device. Range images, gathered
by a particular laser camera, are used in the multi-threshold segmentation. The multi-threshold segmentation is based on the
height of the moving objects. In order to get the precise height of the moving objects, mapping of the original terrain is
performed on the first step. On each layer, the clustering algorithm called iteration-self organizing data analysis techniques
algorithm (ISODATA) is conducted afterwards. Kalman filtering technique is applied to recognize and track the moving objects.
Extensive experiments show that these algorithms are effective in object recognition and tracking, as well as robust in the
applications. 相似文献
182.
The purpose of remote sensing images fusion is to produce a fused image that contains more clear, accurate and comprehensive
information than any single image. A novel fusion method is proposed in this paper based on nonsubsampled contourlet transform
(NSCT) and region segmentation. Firstly, the multispectral image is transformed to intensity-hue-saturation (IHS) system.
Secondly, the panchromatic image and the component intensity of the multispectral image are decomposed by NSCT. Then the NSCT
coefficients of high and low frequency subbands are fused by different rules, respectively. For the high frequency subbands,
the fusion rules are also unalike in the smooth and edge regions. The two regions are segregated in the panchromatic image,
and the segmentation is based on particle swarm optimization. Finally, the fusion image can be obtained by performing inverse
NSCT and inverse IHS transform. The experimental results are evaluated by both subjective and objective criteria. It is shown
that the proposed method can obtain superior results to others. 相似文献
183.
To tackle the key-exposure problem in signature settings, this paper introduces a new cryptographic primitive named threshold
key-insulated signature (TKIS) and proposes a concrete TKIS scheme. For a TKIS system, at least k out of n helpers are needed to update a user’s temporary private key. On the one hand, even if up to k−1 helpers are compromised in addition to the exposure of any of temporary private keys, security of the non-exposed periods
is still assured. On the other hand, even if all the n helpers are compromised, we can still ensure the security of all periods as long as none of temporary private keys is exposed.
Compared with traditional key-insulated signature (KIS) schemes, the proposed TKIS scheme not only greatly enhances the security
of the system, but also provides flexibility and efficiency. 相似文献
184.
The development of an innovative H
∞ controller for looper and tension control in hot strip finishing mills is traced based on approximately linearized model.
This solution has been considered thanks to its well-known robustness and simplicity characteristics concerning disturbances’
attenuation. The controller is designed based on an optimal problem with linear matrix inequality (LMI) constraints, and the
problem is solved by the mincx function of Matlab LMI Toolbox. Simulation results show the effectiveness of the proposed controller
compared with conventional ones. 相似文献
185.
Numerical simulation of macrosegregation during steel ingot solidification using continuum model 总被引:1,自引:0,他引:1
A continuum model is adopted to study the macrosegregation phenomena during solidification of large steel ingots. Evolution
of temperature, melt velocity, and compositional concentration field during a 22 t steel ingot solidification are illustrated
by using the finite volume method. Numerical results of temperature distribution are validated by experiments. The influence
of local permeability relates to the friction that the melt experienced in mushy region is investigated. It is shown that
the continuum model is able to predict the temperature field, and the variation of permeability obviously affects the melt
flowing behavior and the final compositional distribution. 相似文献
186.
High performance computer is often required by model predictive control (MPC) systems due to the heavy online computation
burden. To extend MPC to more application cases with low-cost computation facilities, the implementation of MPC controller
on field programmable gate array (FPGA) system is studied. For the dynamic matrix control (DMC) algorithm, the main design
idea and the implemental strategy of DMC controller are introduced based on a FPGA’s embedded system. The performance tests
show that both the computation efficiency and the accuracy of the proposed controller can be satisfied due to the parallel
computing capability of FPGA. 相似文献
187.
Packet analysis is very important in our digital life. But what protocol analyzers can do is limited because they can only
process data in determined format. This paper puts forward a solution to decode raw data in an unknown format. It is certain
that data can be cut into packets because there are usually characteristic bit sequences in packet headers. The key to solve
the problem is how to find out those characteristic sequences. We present an efficient way of bit sequence enumeration. Both
Aho-Corasick (AC) algorithm and data mining method are used to reduce the cost of the process. 相似文献
188.
An efficient method is proposed for the design of finite impulse response (FIR) filter with arbitrary pass band edge, stop
band edge frequencies and transition width. The proposed FIR band stop filter is designed using craziness based particle swarm
optimization (CRPSO) approach. Given the filter specifications to be realized, the CRPSO algorithm generates a set of optimal
filter coefficients and tries to meet the ideal frequency response characteristics. In this paper, for the given problem,
the realizations of the optimal FIR band pass filters of different orders have been performed. The simulation results have
been compared with those obtained by the well accepted evolutionary algorithms, such as Parks and McClellan algorithm (PMA),
genetic algorithm (GA) and classical particle swarm optimization (PSO). Several numerical design examples justify that the
proposed optimal filter design approach using CRPSO outperforms PMA and PSO, not only in the accuracy of the designed filter
but also in the convergence speed and solution quality. 相似文献
189.
To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat
deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromised mice. The SGDs’s mineralization
pattern and osteogenesis were compared with bone marrow messenchymal stem cells (BMMSCs) from goats. SGDs have similar osteogenic
differentiation pattern in vitro and bone-like tissue formation mechanism in vivo to BMMSCs; moreover SGDs have stronger alkaline
phosphatase (ALP) gene expression and osteopontin (OPN) gene expression levels than BMMSCs; also SGDs can form more bone-like
tissues than BMMSCs when cell-scaffold compounds are transplanted into immunocompromised mice. This pre-clinical study in
a large-animal model confirms that DTSCs may be an appropriate source of stem cells in repairing bone defects with tissue
engineering. 相似文献
190.
Plasma sprayed coatings are built up by the accumulation of splats formed by the impacting, spreading and solidifying of molten
droplets on the substrate. A three-dimensional computational model including heat transfer and solidification is established
to simulate the formation process of a single splat using the computational fluid dynamics (CFD) software, FLUENT. The fluid
flow and energy equations are discretized and solved according to typical finite volume method on an unstructured grid. A
volume of fluid (VOF) tracking algorithm is used to track the droplet flow with free surface. In order to understand the splat
formation mechanism, the process of splat formation caused by impacting and spreading of a molten nickel droplet on a polished
mild steel surface is simulated. On this basis, the simulations of impact of a molten droplet on substrate with different
conditions including the surface morphology, thermal conductivity, initial temperature of the substrate and the thermal contact
resistance are presented. The results clearly show the effect of those parameters on the shape of the final splat and splash
behaviors. 相似文献