Looper-tension <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control for hot strip finishing mills

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.     

Numerical simulation of macrosegregation during steel ingot solidification using continuum model

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.     

Implementation of dynamic matrix control on field programmable gate array

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.     

Bit stream oriented enumeration tree pruning algorithm

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.     

Optimal linear phase finite impulse response band pass filter design using craziness based particle swarm optimization algorithm

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.     

Comparison of osteogenesis between two kinds of stem cells from goat combined calcium phosphate cement in tissue engineering

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.     

Three-dimensional numerical simulation of splat formation on substrates in plasma spraying

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.     

A selection scheme for optimum number of cooperative secondary users in spectrum sensing

An optimization scheme for choosing the optimum number of secondary users in cooperative spectrum sensing based on the cyclostationary feature detection with Neyman-Pearson criterion is proposed in this paper. The optimal soft combination test statistic for the cooperative spectrum sensing based on cyclostationary feature detection is derived according to the generalized likelihood ratio test and its corresponding detection performance is deduced. A target function, considering two important parameters as the resource use efficiency and the number of samples employed by each cooperative secondary user in the system design, is constructed to obtain the optimum number of cooperative secondary users. It can be found that the selection scheme is to make a tradeoff between the system complexity of the cognitive radio network and the global sensing performance of the cooperative spectrum sensing.     

Automatic product image classification with multiple support vector machine classifiers

For the task of visual-based automatic product image classification for e-commerce, this paper constructs a set of support vector machine (SVM) classifiers with different model representations. Each base SVM classifier is trained with either different types of features or different spatial levels. The probability outputs of these SVM classifiers are concatenated into feature vectors for training another SVM classifier with a Gaussian radial basis function (RBF) kernel. This scheme achieves state-of-the-art average accuracy of 86.9% for product image classification on the public product dataset PI 100.     

External equality and absolute equality coincide in finite CCS and <Emphasis Type="Italic">π</Emphasis> calculus without summation

External equality and absolute equality are defined model independently by Fu. It is interesting and important to know whether these two equalities coincide or not. There are some results in Fu’s paper for this issue. It is relatively easy to prove the coincidence if the summation operator is in the language, otherwise it is harder. In fact Fu proposed it as an open problem whether the two equalities coincide in some languages without summation. In this paper, the proofs of the coincidence in finite CCS and π calculus without summation are given.