Design of Home Network Architecture using ACE/TAO Real Time Event Service

This paper proposes a home network design based on publisher/subscriber architecture which is developed using ACE/TAO Real-time Event Service (RTES) as the middleware platform. This design addresses a feature to support a real-time implementation for home network application such as home automation. Home network participants have been classified into several components based on consumer and supplier implementation in the ACE/TAO RTES in order to simplify the design. To optimize the network utilization, events are filtered based on their type and source for each publisher and subscriber. To deal with heterogeneous type of home appliances, event header information has been extended to wrap more information. Each of events can be configured with a specific scheduling and priority setting to meet its quality of service (QoS) according to the requirement. Network performance in handling an increasing number of consumer or supplier has been evaluated and show an acceptable result. Keywords: Home Network, ACE/TAO, RTES, QoS

Patterns for Providing Real-Time Guarantees in DOC Middleware - Doctoral Dissertation, May 2002

The advent of open and widely adopted standards such as Common Object Request Broker Architecture (CORBA) [47] has simplified and standardized the development of distributed applications. For applications with real-time constraints, including avionics, manufacturing, and defense systems, these standards are evolving to include Quality-of-Service (QoS) specifications. Operating systems such as Real-time Linux [60] have responded with interfaces and algorithms to guarantee real-time response; similarly, languages such as Real-time Java [59] include mechanisms for specifying real-time properties for threads. However, the middleware upon which large distributed applications are based has not yet addressed end-to-end guarantees of QoS specifications. Unless this challenge can be met, developers must resort to ad hoc solutions that may not scale or migrate well among different platforms. This thesis provides two contributions to the study of real-time Distributed Object Computing (DOC) middleware. First, it identifies potential bottlenecks and problems with respect to guaranteeing real-time performance in contemporary middleware. Experimental results illustrate how these problems lead to incorrect real-time behavior in contemporary middleware platforms. Second, this thesis presents designs and techniques for providing real-time QoS guarantees in DOC middleware in the context of TAO [6], an open-source and widely adopted implementation of real-time CORBA. Architectural solutions presented here are coupled with empirical evaluations of end-to-end real-time behavior. Analysis of the problems, forces, solutions, and consequences are presented in terms of patterns and frame-works, so that solutions obtained for TAO can be appropriately applied to other real-time systems

PROPOSED MIDDLEWARE SOLUTION FOR RESOURCE-CONSTRAINED DISTRIBUTED EMBEDDED NETWORKS

The explosion in processing power of embedded systems has enabled distributed embedded networks to perform more complicated tasks. Middleware are sets of encapsulations of common and network/operating system-specific functionality into generic, reusable frameworks to manage such distributed networks. This thesis will survey and categorize popular middleware implementations into three adapted layers: host-infrastructure, distribution, and common services. This thesis will then apply a quantitative approach to grading and proposing a single middleware solution from all layers for two target platforms: CubeSats and autonomous unmanned aerial vehicles (UAVs). CubeSats are 10x10x10cm nanosatellites that are popular university-level space missions, and impose power and volume constraints. Autonomous UAVs are similarly-popular hobbyist-level vehicles that exhibit similar power and volume constraints. The MAVLink middleware from the host-infrastructure layer is proposed as the middleware to manage the distributed embedded networks powering these platforms in future projects. Finally, this thesis presents a performance analysis on MAVLink managing the ARM Cortex-M 32-bit processors that power the target platforms

CSP channels for CAN-bus connected embedded control systems

Closed loop control system typically contains multitude of sensors and actuators operated simultaneously. So they are parallel and distributed in its essence. But when mapping this parallelism to software, lot of obstacles concerning multithreading communication and synchronization issues arise. To overcome this problem, the CT kernel/library based on CSP algebra has been developed. This project (TES.5410) is about developing communication extension to the CT library to make it applicable in distributed systems. Since the library is tailored for control systems, properties and requirements of control systems are taken into special consideration. Applicability of existing middleware solutions is examined. A comparison of applicable fieldbus protocols is done in order to determine most suitable ones and CAN fieldbus is chosen to be first fieldbus used. Brief overview of CSP and existing CSP based libraries is given. Middleware architecture is proposed along with few novel ideas

An architecture and execution environment for component integration rules

The Integration Rules (IRules) project at Arizona State University (http://www.eas.asu.edu/~irules) is developing a declarative event-based approach to component integration. Integration rules are based on the concept of active database rules, providing an active approach for specifying event- driven activity in a distributed environment. The IRules project consists of a knowledge model that specifies the IRules Definition Language and an execution model that supports integration rule execution. This research focuses on the execution model and the architectural design parts of the IRules project. The main objective of this research is to develop a distributed execution environment for using integration rules in the integration of black-box components. In particular, this research will investigate the design of an architecture that supports the IRules semantic framework, the development of an execution model for rule and transaction processing, and the design of a rule processing algorithm for coordinating the execution of integration rules. This research will combine the distributed computing framework of Jini, the asynchronous event notification mechanism of the Java Message Service (JMS), and the distributed blocking access functionality of JavaSpaces to support active rule processing in a distributed environment. The limitations of the underlying Enterprise JavaBeans (EJB) component model pose transaction processing challenges for the integration process. This research will develop a suitable transaction model and processing logic to overcome the limitations of the underlying EJB component model. Furthermore, the architectural design will allow an easy extension of the system to accommodate other component models. This research is expected to contribute to nested rule and transaction processing for active rules that have not been previously addressed in distributed rule processing environments. The development of the IRules execution environment will also contribute to the use of distributed rule- based techniques for eventdriven component integration

Discrete Simulation of Distributed Systems - Performance Evaluation of a Notification Channel Federation

This paper presents how discrete simulation can be used for performance evaluation of distributed systems. With this methodology it is not needed to implement the system itself, only a model of proper specification is required. Simulation models for distributed systems can be easily adopted from other models which are already used in network simulations with good results. The tool that supports our measurements is a powerful telecom simulation platform, a simulations development environment that supports object-oriented programming. The model used for demonstration represents a notification channel federation including an arbitrary number of event suppliers and event consumers connected to a scalable network. Performance is evaluated for various configurations, and results are presented