[Show abstract][Hide abstract]ABSTRACT: Many real-time distributed computing (RTDC) applications have stringent action timing requirements as well as tight security-enforcement requirements. Integration of security enforcement mechanisms into advanced component-based RTDC schemes has been recognized as an important research topic in recent years. In this paper we propose the first formal extension of the Time-triggered Message-triggered Object (TMO) component model devised to facilitate efficient construction of secure RTDC applications. The newly extended TMO structure is called the Adaptive Secure TMO (AS-TMO). A distinguishing characteristic of the proposed scheme is that security attributes (e.g., roles) are associated with AS-TMO parts (e.g., methods and data-container variable groups) instead of with entire AS-TMOs. We also present the execution engine facilities being incorporated into the middleware model, the TMO Support Middleware (TMOSM), for providing the security-enforcement capabilities defined in the AS-TMO scheme.
[Show abstract][Hide abstract]ABSTRACT: An attractive program component model for use in constructing reliable networks of sensor nodes communicating via wireless channels is the time-triggered function (TTF). In general, when an application is structured as a network of TTFs, the timing behavior of the application can be analyzed relatively easily. The TTF network programming model has been refined somewhat in the past two years. Also, in the past five years, we have been refining the architecture and a prototype of a small-footprint time-sliced multi-threading kernel that runs on a communicating-sensor platform and contains TTF support mechanisms. The kernel is called the TTF Support OS (TSOS). Some of the refinements made are discussed here. Also, some performance evaluations of both the refined TSOS prototype and the TTF programming scheme have been conducted and the results are presented
[Show abstract][Hide abstract]ABSTRACT: Developing distributed real-time systems with high degrees of assurance on the system reliability is becoming increasingly
important, yet remains difficult and error-prone. The Time-triggered Message-triggered Object (TMO) scheme is a high-level
distributed object-oriented programming approach that has proved to be effective in developing such systems. The TMO programming
scheme allows real-time application developers to explicitly specify temporal constraints in terms of global time in simple
and natural forms. TMOSM is a middleware model that provides the execution support mechanisms for TMOs and TMOSL is a C++
class library that provides a convenient application programming interface (API) for developing TMO applications. The TMO
scheme, TMOSM, and TMOSL have evolved during these years in order to support complex distributed real-time applications more
effectively. This paper presents some recent additions on the TMOSM API that resulted from this evolution.
[Show abstract][Hide abstract]ABSTRACT: Inheritance in real-time object-oriented programming is a young subject for research, let alone for practice. Issues in inheritance
design are discussed in the context of TMO (Time-Triggered Message-Triggered Object) scheme for real-time distributed object programming. The TMO scheme guides programmers to incorporate timing specifications
in natural, modular, and easily analyzable forms. The scheme thus makes it relatively easy to practice inheritance design.
Some TMO structuring rules and styles that enable efficient design of inheritance are presented. A GUI-based approach for
TMO-framework programming with exploitation of inheritance is also discussed.
[Show abstract][Hide abstract]ABSTRACT: We present a new class of multimedia applications where the exploitation of the principle of globaltime- based coordination of distributed actions (TCoDA) is compelling. In these applications, multiple smallfootprint PCs, each equipped with its own speakers, act as instrument players or singers forming an ensemble. Each player PC obtains its piece of the musical audio data over an Ethernet network from a central server containing all necessary audio files. An important requirement is thus to make multiple specialized players, e.g., violin player, cello player, piano player, etc., perform globally synchronous play of their responsible pieces of the music. Moreover, to enable fast start of the requested music play, the musical data are streamed from the server to each player in a pipelined fashion so that while each player is playing one part of the music, the next part may be arriving over the network. Efficient implementation techniques based on the TMO programming scheme are then presented. This digital music ensemble application turns out to be an interesting cost-effective means of evaluating the QoS of the middleware supporting TCoDA. A prototype implementation of a digital music ensemble system was relatively easily realized by use of the TMO programming scheme.