Adrian Noguero

Supporting a reconfigurable real-time service-oriented middleware with FTT-CORBA

Modern distributed real-time systems (DRTS) are typically formed by several heterogeneous networked devices. Sometimes these devices must adapt to dynamic environments in which devices may join or leave the network and must respond in run-time to changing requirements ensuring certain levels of QoS. These characteristics yield to systems that are intrinsically complex to develop, test and maintain. In this scenario middleware platforms, and particularly Service-Oriented Architectures (SOA), are becoming increasingly popular because they ease the creation of complex distributed applications and reduce the time-to-market. In this paper we show how the recently developed Flexible Time-Triggered CORBA (FTT-CORBA) can be used to support real-time Service-Oriented Architectures that are deterministically and dynamically reconfigurable.

A Novel Synchronous Scheduling Service for CORBA-RT Applications

Although distributed real-time (RT) systems are intrinsically complex to develop and maintain, the use of certain object-oriented (OO) technologies such as CORBA and CORBA-RT facilitates those tasks. This is the main reason why these technologies are becoming increasingly popular. Moreover, CORBA is complemented with additional services that solve specific requirements for some applications, so developers may concentrate on the application functionality. Following this approach, this paper presents a new service that allows the synchronous scheduling of different activities in a distributed RT system in a simple and flexible way. This paper also explains how this service can be used for optimizing that access to shared resources in a distributed system and presents several experimental data that show the service performance

A time-triggered data distribution service for FTT-CORBA

FTT-CORBA is a middleware architecture aimed at synchronizing the task activations of a distributed system according to a plan that may be changed at runtime. In this architecture tasks are wrapped within CORBA methods that are activated by a central node, the Orchestrator, over a LAN. Previous versions of FTT-CORBA focused on CPU-bound applications in which the communication time was neglectable. However, in some cases, this assumption is not valid. This work presents an add-on service, integrated within the FTT-CORBA middleware, aimed at minimizing the interference among task activation and data distribution messages. By using this new service the Orchestrator will be capable of controlling the transmission of data distribution packages from the distributed nodes by dynamically allocating them in specific time slots.

Towards a modular and scalable design for the communications of electrical protection relays

The present work proposes the use of a combination of standardized middleware technologies, such as CORBA-RT and DDS in order to build electrical protection relays in a modular and scalable way. Both CORBA and DDS follow different approaches, while CORBA is basically a client / server architecture, DDS follows the publisher/subscriber paradigm. However, IEDs generate different types of traffic that could be mapped to either CORBA, or DDS operations, leaving DDS for the most critical ones: the distribution of periodic samples values and substation events. The paper also analyses the behaviour of DDS for these types of operations.

FTT-MA: A Flexible Time-Triggered Middleware Architecture for Time Sensitive, Resource-Aware AmI Systems

There is an increasing number of Ambient Intelligence (AmI) systems that are time-sensitive and resource-aware. From healthcare to building and even home/office automation, it is now common to find systems combining interactive and sensing multimedia traffic with relatively simple sensors and actuators (door locks, presence detectors, RFIDs, HVAC, information panels, etc.). Many of these are today known as Cyber-Physical Systems (CPS). Quite frequently, these systems must be capable of (1) prioritizing different traffic flows (process data, alarms, non-critical data, etc.), (2) synchronizing actions in several distributed devices and, to certain degree, (3) easing resource management (e.g., detecting faulty nodes, managing battery levels, handling overloads, etc.). This work presents FTT-MA, a high-level middleware architecture aimed at easing the design, deployment and operation of such AmI systems. FTT-MA ensures that both functional and non-functional aspects of the applications are met even during reconfiguration stages. The paper also proposes a methodology, together with a design tool, to create this kind of systems. Finally, a sample case study is presented that illustrates the use of the middleware and the methodology proposed in the paper.

A time-triggered middleware architecture for ubiquitous cyber physical system applications

Cyber Physical Systems (CPS) are a special type of ubiquitous systems where control theory, communications and real-time computing are combined in embedded applications that interact with the physical world. The development of these applications becomes more complex when real-time and other non-functional requirements are to be satisfied. This paper presents a time-triggered middleware architecture that provides fault tolerance and dynamic reconfiguration at run-time taking into account the available resources of the underlying infrastructure, i.e. devices and communication networks. This architecture aims at easing the development of ubiquitous applications based on CPS. The paper provides an overview of the design of the architecture and discusses some implementation issues.

Distribution middleware technologies for Cyber Physical Systems

Cyber-Physical Systems (CPS) are integrations of computation and physical processes. This kind of systems is being increasingly used in different domains such as healthcare, transportation, process control, manufacturing or electric power grids. CPS interact with the physical world and must operate dependably, safely, securely, efficiently and, frequently, in real-time. Consequently, they require new computing and networking technologies capable of supporting them adequately in environments qualitatively different from those found in general purpose computing. This paper analyzes the applicability of different middleware technologies as data distribution means for CPS.

Configurable cooperative middleware for the next generation of CPS

Cyber-Physical Systems (CPS) form an emerging discipline that integrates embedded computers with the physical processes under control. Typically, Cyber-Physical applications include low profile computing components, such as sensors and actuators that must communicate to carry out complex tasks. They may be found in different applications domains e.g. intelligent buildings, industrial automation or critical infrastructure control. This kind of applications requires certain features such as autonomy, fault tolerance, energy efficiency or solving heterogeneity and configurability issues. However, managing the communication issues in this kind of applications can be relatively complex. In this scenario, middleware technologies can help developers in the design of the next generation of CPS. This work describes the design principles of a type of CPS that requires cooperation. More specifically, it presents a generic family of logical cooperation topologies capable of adapting dynamically to changes in the environment.

A Model for System Resources in Flexible Time-Triggered Middleware Architectures

Middleware has become a key element in the development of distributed Cyber Physical Systems (CPS). Such systems often have strict non-functional requirements, and designers need a means to predict and manage non-functional properties. In this work, the authors present a mathematical model for the most relevant resources managed by FTT middleware architectures; namely, (1) processor, (2) memory, (3) energy and (4) network. This model can be used both off-line for simulation and designing purposes of a Cyber Physical System (CPS), or in run-time within an admission test or inside the algorithm of a specific scheduling policy executed by the middleware. In such case, the admission test is aimed at predicting whether a system fulfils the non-functional requirements or not before carrying out any modification in its execution plan at run-time.

A framework with proactive nodes for scheduling and optimizing distributed embedded systems

A new generation of distributed embedded systems (DES) is coming up in which several heterogeneous networked devices execute distributed applications. Such heterogeneity may apply to size, physical boundaries as well as functional and non-functional requirements. Typically, these systems are immersed in changing environments that produce dynamic requirements to which they must adapt. In this scenario, many complex issues that must be solved arise, such as remote task preemptions, keeping task precedence dependencies, etc. This paper presents a framework aimed at DES in which a central node, the Global Scheduler (GS), orchestrates the execution of all tasks in a DES. The distributed nodes take a proactive role by notifying the GS when they are capable of executing new tasks. The proposed approach requires from the underlying technology support for task migrations and local preemption at the distributed nodes level.