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Wireless Sensor Networks (WSNs) have become widely used in various fields like environmental monitoring, smart agriculture, and health care. However, their extensive usage also introduces significant vulnerabilities to cyber viruses. Addressing this security issue in WSNs is very challenging due to their inherent limitations in energy and bandwidth to implement real-time security measures. To tackle the virus issue, it is crucial to first understand how it spreads in WSNs. In this brief, we propose a novel epidemic spreading model for WSNs, integrating the susceptible-infected-susceptible (SIS) epidemic spreading model and node probabilistic sleep scheduling--a critical mechanism for optimizing energy efficiency. Using the microscopic Markov chain (MMC) method, we derive the spreading equations and epidemic threshold of our model. We conduct numerical simulations to validate the theoretical results and investigate the impact of key factors on epidemic spreading in WSNs. Notably, we discover that the epidemic threshold is directly proportional to the ratio of node sleeping and node activation probabilities., This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible

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Laser peening is a novel surface treatment technique for improving the mechanical properties of metal parts' surface. To investigate and evaluate the effect of laser peening on the microstructural changes, texture evolution, and residual stress distribution changes, laser peening experiment was undertaken using Nd:YAG laser system with the pulse–width of 20 ns and max pulse–energy of 9 J. Micro-hardness measurements of the untreated and treated specimens were carried out with Vickers indenter. Depth-resolved characterization of the residual stresses and strains was achieved using X-ray diffraction. The structure–texture–phase–stress combined analysis was performed based on the X-ray diffraction patterns using the whole pattern fitting method. The relationship between laser peening processing parameters, microstructure, texture, residual stress distribution and hardness are presented and discussed. The results showed that laser peening could improve microstructures and properties of TiAl alloy.

In the open, dynamic and uncertain environment of the Internet, service substitution is a key tech- nique to keep the service-oriented software system trustworthy. Most of the existing approaches analyze BPEL service substitutability at the control-flow model level without considering the data aspect of BPEL services. Moreover, existing approaches are too conservative when the BPEL processes asynchronously invoke the dis- tributed partner services. To address this problem, we propose a novel approach to analyzing BPEL service substitutability which is based on the program dependence graphs of BPEL services. Our approach takes control dependence, data dependence, asyn-invocation dependence, interaction dependence into account, and thus it can appropriately cope with the problem of BPEL service substitution. We use a running case study of substituting a travel agency BPEL service to illustrate the validity and feasibility of our approach.

Constraint specifications for access control organize a set of constraints to control human-computer interaction for users to perform their duties securely and efficiently. Constraint specifications are imperative for the access control and security management of large and complex multi-user interactive applications. Existing specifications of Role-based Access Control are incomplete and complicated. This paper proposes a framework of well-defined constraint specifications for developers to build application-level access control based on users' roles. They ensure that each role is configured with consistent privileges, each actor is authorized to proper roles and then each actor can activate and play his authorized roles without interest conflicts. These formal specifications are consistent and inferable, complete and simplified, abundant and scalable for diversified multi-user applications.

A new secure Windows terminal based on heterogeneous dual-subsystem architecture is proposed to resolve the security problems of Windows terminals. The secure terminal includes a prime subsystem and an assistant subsystem. The prime subsystem, which handles man-machine interactive and mission-related programs, is compliant to Windows. The assistant subsystem, which provides main security mechanisms as security machine, is closely connected with prime subsystem through fast internal interface. In fact, it is an embedded computer with operating system and security mechanisms which control all data flow of terminal passing through network. The design and implementation of the secure terminal which includes hardware architecture,software structure and security mechanisms are given, and the advantages of the architecture are also analyzed.