Cloud-Based User Behavior Emulation Approach for Space-Ground Integrated Networks

Cyber-physical systems (CPSs) based on space-ground integrated networks (SGINs) enable CPSs to break through geographical restrictions in space. Therefore, providing a test platform is necessary for new technical verification and network security strategy evaluations of SGINs. User behavior emulation technology can effectively support the construction of a test platform. Given the inherent dynamic changes, diverse behaviors, and large-scale characteristics of SGIN users, we propose user behavior emulation technology based on a cloud platform. First, the dynamic emulation architecture for user behavior for SGINs is designed. Then, normal user behavior emulation strategy driven by the group user behavior model in real time is proposed, which can improve the fidelity of emulation. Moreover, rogue user behavior emulation technology is adopted, based on traffic replay, to perform the security evaluation. Specifically, virtual Internet Protocol (IP) technology and the epoll model are effectively integrated in this investigation to resolve the contradiction between large-scale emulation and computational overhead. The experimental results demonstrate that the strategy meets the requirement of a diverse and high-fidelity dynamic user behavior emulation and reaches the emulation scale of 100,000-level concurrent communication for normal users and 100,000-level concurrent attacks for rogue users.

Tansy: Extensible, Concurrent Communication

The cryptoanalysis approach to the partition table is defined not only by the understanding of infor-mation retrieval systems, but also by the intuitive need for the Ethernet. In fact, few cyberinformati-cians would disagree with the evaluation of hash ta-bles [13]. Here, we use stable configurations to val-idate that semaphores and Lamport clocks can col-lude to surmount this grand challenge

Tilted transverse isotropic reverse time migration with angle gathers: Implementation and efficiency

We have developed a 3D reverse time migration (RTM) implementation, with an extended imaging condition, in the presence of tilted transverse isotropy (TTI), using finite-difference time-domain solvers on the rotated staggered grid (RSG) and the Lebedev grid. We have evaluated dispersion analysis of both schemes for a sample TTI medium. Using synthetic and real seismic data in realistic execution configurations, we found surprising inconsistency with quantitative cost estimates in the literature. For fixed accuracy, the RSG scheme proved most efficient in our tests, and not two to three times less efficient, as had been posited. Of course, variability may arise with particular medium properties, computer architectures, or software implementations. Having analyzed wavefield modeling performance in detail, we then quantified the realistic costs associated with the imaging condition in RTM, especially extended imaging conditions. For large extensions of the imaging condition, the associated cost dominates the total execution time and adds very significantly to the total cost of the migration. Our implementation targets both shared and distributed memory parallelism, making it suitable for general CPU clusters, nonuniform memory access architectures, and Intel Xeon-Phi. We have also discussed other aspects of our implementation in detail. In particular, we have explored an alternative method to achieve concurrent communication and computation in RTM.

Developing a Web-Based Cooperative Environment to Software Project Development

A software project is developed by collaboration of some expert people. However, the collaboration puts obstacles in the way of software development when the involved people in the project are scattered over the world. Although Internet has provided a collection of scattered islands in which the denizens of the islands are able to communicate with each other, it lacks full requisite qualifications for the collaboration among the denizens. The emerging idea is that a supportive environment should be developed on the Web for providing full requisite qualifications and facilitating collaboration. Towards providing such an environment, this chapter aims to present a framework exploiting Open Hypermedia System (OHS) and a Web-based collaboration protocol. OHS assists in saving and restoring artifacts constructed by the scattered people, and the protocol provides channels to concurrent communication and distributed authoring among the people.