A Generative Middleware for Heterogeneous and Distributed Services

International audienceModern software-based services increasingly rely on a highly heterogeneous and dynamic interconnection of platforms and devices offering a wide diversity of capabilities ranging from cloud server with virtually unlimited resources down to micro-controllers with only a few KB of RAM. This paper motivates the fact that no single software framework or software engineering approach is suited to span across this range, and proposes an approach which leverages the latest advances in model-driven engineering, generative techniques and models@runtime in order to tame this tremendous heterogeneity. This paper presents a set of languages dedicated to the integration, deployment and continuous operation of existing libraries and components already available and implemented in various languages. The proposed approach is validated on an industrial case study in the eHealth domain, implemented by an industrial partner that provide an qualitative evaluation of the approach. This case study involves a large number of sensors, devices and gateways based on Rasperry Pi, Intel Edison and Arduino

Specification and Refinement of Soft Real-time Requirements Using Sequence Diagrams

Soft real-time requirements are often related to communication in distributed systems. Therefore it is interesting to understand how UML sequence diagrams can be used to specify such requirements. We propose a way of integrating soft real-time requirements in sequence diagram specifications by adding probabilities to timed sequence diagrams. Our approach builds on timed STAIRS, which is an approach to the compositional and incremental development of sequence diagrams supporting specification of mandatory as well as potential behavior

Backstepping Designs For Nonlinear Way-Point Tracking Of Ships

. Nonlinear tracking of ships in terms of way-points for route planning is discussed. A tracking control law that handles different curvatures of a path, e.g. combinations of straight-lines and circles, is developed by using nonlinear backstepping. Exponential stability is proven by applying Lyapunov stability theory. An extension to integral action is also made. However, only convergence is guaranteed for the case when integral action is included. Key Words. Way-Point Tracking, Guidance of Ships, Marine Systems, Ship Control, Nonlinear Backstepping. 1. INTRODUCTION Since the kinematic equations of motion are highly nonlinear during turning of a ship, the authors propose to use nonlinear backstepping and Lyapunov stability theory to solve the ship tracking problem (Krsti'c et al., 1995). This implies that the nonlinearities in the system equations can be handled without linearization. This paper proposes a smooth nonlinear control law for tracking of both straight-lines and circle arc..

Why timed sequence diagrams require three-event semantics

Abstract. STAIRS is an approach to the compositional development of sequence diagrams supporting the specification of mandatory as well as potential behavior. In order to express the necessary distinction between black-box and glass-box refinement, an extension of the semantic framework with three event messages is introduced. A concrete syntax is also proposed. The proposed extension is especially useful when describing time constraints. The resulting approach, referred to as Timed STAIRS, is formally underpinned by denotational trace semantics. A trace is a sequence of three kinds of events: events for transmission, reception and consumption. We argue that such traces give the necessary expressiveness to capture the standard UML interpretation of sequence diagrams as well as the black-box interpretation found in classical formal methods. 1 Introduction to STAIRS Sequence diagrams have been used informally for several decades. The first standardization of sequence diagrams came in 1992 [ITU93] – often referred to a

A conceptual model for service availability

Traditionally, availability has been seen as an atomic property asserting the average time a system is “up ” or “down”. In order to model and analyse the availability of computerised systems in a world where the dependency on and complexity of such systems are increasing, this notion of availability is no longer sufficient. This report presents a conceptual model for service availability designed to handle these challenges. The core of this model is a characterisation of service availability by means of accessibility properties and exclusivity properties, which is further specialised into measurable aspects of service availability. We outline how this conceptual model may be refined to a framework for specifying and analysing availability requirements