Immune responses are based on the coordinated searching behaviors of immunocytes that are aimed at tracking down specific targets. The search efficiency of immunocytes significantly affects the speed of initiation and development of immune responses. Previous studies have shown that not only the intermittent walk but also the zigzag turning preference of immunocytes contributes to the search efficiency. However, among existing models describing immunocytes' search strategy, none has captured both features. Here we propose a zigzag generalized Lévy walk model to describe the search strategy of immunocytes more accurately and comprehensively by considering both the intermittent and the zigzag-turning walk features. Based on the analysis of the searching behaviors of typical immune cell types, dendritic cells and leukocytes, in their native physiological environment, we demonstrate that the model can describe the in vivo search strategy of immunocytes well. Furthermore, by analyzing the search efficiency, we find that this type of search strategy enables immunocytes to capture rare targets in approximately half the time than the previously proposed generalized Lévy walk. This study sheds new light on the fundamental mechanisms that drive the efficient initiation and development of immune responses and in turn may lead to the development of novel therapeutic approaches for diseases ranging from infection to cancer.

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A novel quantization-based switched second-order sliding mode control design is considered for nonlinear uncertain systems. A new quantization strategy associated with state-space partition is utilized to accommodate the control amplitude to different uncertainty levels then the conservatism of the control gain is thus attenuated. Investigating each quantized region, it is obtained that all regions are globally invariant sets which offers a monotonously consecutive decrease of the quantized control amplitude when sliding variable converging to the origin through considered uncertainty levels. To deal with different control objectives, the closed-loop system performance can be enhanced via adapting the quantization parameters. The finite-time stability analysis and the effect assessment of quantization parameter on the total convergence time are provided. Simulation shows the efficacy and superiority compared with referenced methods.

Aimed at the problem of the fairness analysis for multiparty nonrepudiation protocols, a new formal analysis method based on improved strand space is presented. Based on the strand space theory, signature operation is added; the set of terms, the subterm relation and the set of penetrator traces are redefined and the assumption of free encryption is extended in the new method. The formal definition of fairness in multi-party non-repudiation protocols is given and the guideline to verify it based on improved strand space is presented. Finally, the fairness of multi-party non-repudiation protocols is verified with an example of Kremer-Markowitch protocol, which indicates that the new method is suitable for analyzing the fairness of multiparty nonrepudiation protocols. Hindawi Publishing Corporation

With the rapid development of electronic technology, high frequency switching power supply has been widely used in various electrical equipment, and its electromagnetic interference has attracted more and more attention. In this paper, the harmonic balance finite element method is used to solve the electromagnetic compatibility of high frequency switching power supply. In this method, the coefficients of sine wave are applied to represent the waveform, and the solution is generated by linear synthesis. We propose to combine it with the finite element method to solve the steady-state response of electromagnetic field in frequency domain. It is proved the method we proposed is superior to the traditional time domain method.