Advanced Materials Research Vols. 490-495

Abstract: As remote ships have equipped a large number of computer equipments, the maintenance of such equipments confronts a great challenge. Since some embedded devices among them may be hacked by attackers or disabled by Byzantine failure, to discover the attacking originality and fault source present foremost importance. In this article, we discuss digital investigation and forensics as a general viewpoint. We point out some dilemmas that hinder the development of digital forensics, some of which may be fundamental problems. We propose to expand the concept of digital forensics to a wider scope so as to include digital investigation for information instead of only evidence. We also argue that the fostering of novel contributions should be relied on technical experts instead of law experts as emerging new techniques always result in new digital crimes. We promote the divorce between the technical experts who focus on the contribution of technologies, and legal authorities who are responsible to bridge the gap between technologies and standard/formalization. Digital forensics methods are encouraged to be publicly available, but the contributors should be aware of the possibility of anti-forensics.

Abstract: Aiming at wide variations in loads and moment of inertia, large disturbed moment of a rocket launcher position servo system, a backstepping sliding mode control method was present. The proposed method combines the backstepping control with the classical sliding mode control in order to limit the matched disturbances and the unmatched disturbances , which are caused by the gas flow impact and the moment of inertia disturbance respectively. The simulation results show that the proposed approach can guarantee accuracy and increase the response speed and possesses a strong robustness to the matched disturbances and the unmatched disturbances.

Abstract: Topology control is an efficient approach which can reduce energy consumption for wireless sensor networks, and the current algorithms mostly focus on reducing the nodes’ energy consumption by power adjusting, but pay little attention to balance energy consumption of the whole network, which results in premature death of many nodes. Thus, a distributed topology control algorithm based on path-loss and residual energy (PRTC) is designed in this paper. This algorithm not only maintains the least loss links between nodes but also balances the energy consumption of the network. The simulation results show that the topology constructed by PRTC can preserve network connectivity as well as extend the lifetime of the network and provide good performance of energy consumption.

Abstract: In this paper, we proposed the covering fuzzy rough set model based on multi-granulations and discussed some interesting properties about the model. The research may enlarge the application range of the rough set theory in real life. The lower and upper approximations of fuzzy set are defined by multi-covering relations on the universe, and some basic properties are introduced. It is shown that the fuzzy rough set model based on multi-covering relations is an extension of the rough set model based on multi-granulations.

Abstract: A problem is aroused in multi-classifier system that normally each of the classifiers is considered equally important in evidences’ combination, which gone against with the knowledge that different classifier has various performance due to diversity of classifiers. Therefore, how to determine the weights of individual classifier in order to get more accurate results becomes a question need to be solved. An optimal weight learning method is presented in this paper. First, the training samples are respectively input into the multi-classifier system based on Dempster-Shafer theory in order to obtain the output vector. Then the error is calculated by means of figuring up the distance between the output vector and class vector of corresponding training sample, and the objective function is defined as mean-square error of all the training samples. The optimal weight vector is obtained by means of minimizing the objective function. Finally, new samples are classified according to the optimal weight vector. The effectiveness of this method is illustrated by the UCI standard data set and electric actuator fault diagnostic experiment.

Abstract: In the paper the authors propose a combination of the EMD (empirical mode decomposition)method and the wavelet analysis to suppress the noise and fault detection and diagnosis, It adopts empirical mode decomposition to current signal ,obtained a series of IMFs(Intrinsic Mode Function),removing the first IMF component to denosing,and then analyzed multi-scale ,using signal become mutated have the maximum modulus determine the time that the failure appeared ,the results show that this method determine the time that the failure appeared.

Abstract: Most existing routing protocols for delay tolerant mobile sensor network(DTMSN) based on simplistic random mobility models. However, the real-life mobility pattern is complicated. We propose a real-life mobility patterns based routing protocol in DTMSN, The simulation results show that RMPR achieves higher delivery ratio and lower delay and transmission overhead

Abstract: Through the simple introduction of a sound measuring temperature system, the basic structure of the system composition can be gotten. Then the design of the software is particularly introduced. This paper mainly describes the Site Control Part and Monitoring Center Part of the operation monitoring through the simulation of a set of experimental devices. It describes all the functions of the two parts. What’s more, the software communication protocol, fault analysis and software operational testing program are also briefly introduced in this paper

Abstract: This paper proposes an IMF-based traffic prediction method. According with the characteristics of each IMF (Intrinsic Mode Function), different models are adopted for the prediction of IMFs. Experiments are carried out based on real traffic. And the experimental results show that the proposed method not only solves mode mixing but also increases the prediction accuracy.

Abstract: In the paper, a new variable step size LMS algorithm based on modified hyperbolic tangent is presented. In the algorithm, the step size is adjusted by the estimation of the autocorrelation between and .The algorithm introduces the compensation monomial to improve the convergence and the parameters to improve the shape and bottom characteristic of hyperbolic tangent. Therefore, the algorithm has faster convergence, better performance of noise suppression，lower steady state error and misadjustment. The theoretical analysis and simulation results all show that the overall performance of the new algorithm exceeds greatly some existent others under low SNR condition.