Tenant-centric Sub-Tenancy Architecture in Software-as-a-Service

AbstractMulti-tenancy architecture (MTA) is often used in Software-as-a-Service (SaaS) and the central idea is that multiple tenant applications can be developed using components stored in the SaaS infrastructure. Recently, MTA has been extended to allow a tenant application to have its own sub-tenants, where the tenant application acts like a SaaS infrastructure. In other words, MTA is extended to STA (Sub-Tenancy Architecture). In STA, each tenant application needs not only to develop its own functionalities, but also to prepare an infrastructure to allow its sub-tenants to develop customized applications. This paper applies Crowdsourcing as the core to STA component in the development life cycle. In addition, to discovering adequate fit tenant developers or components to help build and compose new components, dynamic and static ranking models are proposed. Furthermore, rank computation architecture is presented to deal with the case when the number of tenants and components becomes huge. Finally, experiments are performed to demonstrate that the ranking models and the rank computation architecture work as design

Exploring AADL verification tool through model transformation

International audienceArchitecture Analysis and Design Language (AADL) is often used to model safety-critical real-time systems. Model transformation is widely used to extract a formal specification so that AADL models can be verified and analyzed by existing tools. Timed Abstract State Machine (TASM) is a formalism not only able to specify behavior and communication but also timing and resource aspects of the system. To verify functional and nonfunctional properties of AADL models, this paper presents a methodology for translating AADL to TASM. Our main contribution is to formally define the translation rules from an adequate subset of AADL (including thread component, port communication, behavior annex and mode change) into TASM. Based on these rules, a tool called AADL2TASM is implemented using Atlas Transformation Language (ATL). Finally, a case study from an actual data processing unit of a satellite is provided to validate the transformation and illustrate the practicality of the approach

Simulation of real-time systems with clock calculus

International audienceSafety–critical real-time systems need to be modeled and simulated early in the development of lifecycle. SIGNAL is a data-flow synchronous language with clocks widely used in modeling of such systems. Due to the synchronous features of SIGNAL, clock calculus is essential in compilation and simulation. This paper proposes a new methodology for clock calculus that takes data dependencies into consideration. In this way, simulation code can be directly generated by using a depth-first traversal algorithm. In addition, a clock insertion method based on clock-implication checking is presented to obtain an optimized control structure

Servicetizing User Experiences for Complex Business Applications

Web interfaces have been widely used to support user interactions in complex business applications. In a typical design of such an application, the execution is driven by the http requests sent by the web-browser. Thus, the control of the workflow is encoded by the hyperlinks and buttons embedded in various web pages that support the user interactions. This web-driven design makes it hard to reason about and to maintain the workflows, especially when the web pages are dynamically generated at runtime. This design also increases the complexity in developing rich user interactions for complex workflows. In this paper, we propose a new design that separates the workflow specification from the user interaction specification in a business application. This design is based on a workflow-driven service-oriented architecture pattern. In this architecture, the user interactions are captured by user experience services that can be developed, deployed, and maintained independently of the application. These services can be composed together with other business services by an executable workflow specification to provide the functionalities required by the application. This approach increases the flexibility in the implementation of the user interactions. It also enables a model-driven development approach for implementing the workflows that involve sophisticated user interactions

Asynchronous Federated Learning System Based on Permissioned Blockchains

The existing federated learning framework is based on the centralized model coordinator, which still faces serious security challenges such as device differentiated computing power, single point of failure, poor privacy, and lack of Byzantine fault tolerance. In this paper, we propose an asynchronous federated learning system based on permissioned blockchains, using permissioned blockchains as the federated learning server, which is composed of a main-blockchain and multiple sub-blockchains, with each sub-blockchain responsible for partial model parameter updates and the main-blockchain responsible for global model parameter updates. Based on this architecture, a federated learning asynchronous aggregation protocol based on permissioned blockchain is proposed that can effectively alleviate the synchronous federated learning algorithm by integrating the learned model into the blockchain and performing two-order aggregation calculations. Therefore, the overhead of synchronization problems and the reliability of shared data is also guaranteed. We conducted some simulation experiments and the experimental results showed that the proposed architecture could maintain good training performances when dealing with a small number of malicious nodes and differentiated data quality, which has good fault tolerance, and can be applied to edge computing scenarios

Scheduling Simulation in a Distributed Wireless Embedded System, SIMULATION: Transactions of the Society for Modeling and Simulation

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