The cover image is based on the Original Article Verification Algebra for Multi-Tenant Applications in VaaS Architecture by Kan Luo et al., https://doi.org/10.1002/stvr.1763.

Summary This paper proposes an algebraic system, verification algebra (VA), for reducing the number of component combinations to be verified in multi‐tenant architecture (MTA). MTA is a design architecture used in SaaS (Software‐as‐a‐Service) where a tenant can customize its applications by integrating services already stored in the SaaS databases or newly supplied services. Similar to SaaS, VaaS (Verification‐as‐a‐Service) is a verification service in a cloud that leverages the computing power offered by a cloud environment with automated provisioning, scalability and service composition. In VaaS architecture, however, there is a challenging problem called ‘combinatorial explosion’ that it is difficult to verify a large number of compositions constructed by both quantities of components and various combination structures even with computing resources in cloud. This paper proposes rules to emerge combinations status for future verification, on the basis of the existing results. Both composition patterns and properties are considered and analysed in VA rules.

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The contradiction between ever increasing satellite communication traffic and limited satellite transponder resources motivates a more dynamic allocation and more effective utilization of satellite transponders' resources. In this paper, the link capacity for a smart satellite transponder is maximized with limited available power and spectrum resource at satellite transponder. Specifically, given that the satellite transponder broadcasts the signals from the gateway station to the multiple satellite terminals with minimum transmission rate requirement, the satellite transponder needs to provide as large link capacity as possible to gateway station for the amount data transmission of special demands. The problem is formulated with aim of maximizing link capacity, and subject to minimum transmission rate requirement of link to satellite terminals and available resource allocation. The finely-matched dynamic power and spectrum allocation scheme is proposed to achieve maximization of both target link capacity and transponder resource utilization. Simulations results demonstrate that the proposed scheme outperforms tradition schemes and the superiority is even more remarkable in multi-constrained situations.

In Software Defined Networks (SDN), though we can design protection mechanism to enable fast recovery against a single link failure, it requires proactively installing a large number of flow entries in switches on working paths and backup paths. However, these additional flow entries in a SDN switch may exhaust Ternary Content Addressable Memory (TCAM) which is limited in size since it is expensive and power hungry. Accordingly, it is emergent to design a new protection technology to minimize flow entry occupation. To this end, we leverage flow entry sharing in SDN protection to solve this problem. We first present the problem as an ILP (Integer Linear Programming) model, and then design a greedy based heuristic algorithm named Flow Entry Sharing Protection (FESP). Extensive simulation results show that compared with the previous SDN protection algorithms, FESP reduces 28.31% flow entries and 27.65% link bandwidth in average.

Virtualization has been seen as one of the main evolution trends in future cellular networks which enables the decoupling of infrastructure from the services it provides. In this case, the roles of infrastructure providers (InPs) and mobile virtual network operators (MVNOs) can be logically separated and the resources of a base station owned by an InP can be transparently shared by multiple MVNOs, while each MVNO virtually owns the entire BS. Naturally, the issue of resource allocation arises. Specifically, the InP is required to abstract the physical resources into isolated slices for each MVNO who then allocates the resources within the slice to its subscribed users. In this paper, we aim to address this two-level hierarchical resource allocation problem while satisfying the requirements of efficient resource allocation, strict inter-slice isolation, and the ability of intra-slice customization. To this end, we propose a hierarchical combinatorial auction model, based on which a truthful and efficient resource allocation framework is provided. And we show by an illustrative example how the proposed model can be applied for wireless virtualization. Specifically, winner determination problems (WDPs) are formulated for the InP and MVNOs, and computationally tractable algorithms are proposed for solving these WDPs. Also, pricing schemes are proposed for ensuring the incentive compatibility. Note that the proposed model can be generalized for the virtualization of resources with more dimensions (e.g., power, antennas, etc.).