MASS - A Real-Time Activation Oriented Specification Language

This report presents an activation oriented approach for RTS specification, formalized in a language called MASS

Real-Time Systems Development with MASS

In this paper, we demonstrate the capability of mass, a real-time design language, for large systems specification. The paper presents a hierarchical specification of an automatic cruise controller that evolves through stepwise refinement. In particular, we show modular design, the separation of the functional and reactive concerns, and the succinct and intuitive nature of specifications in mass. 1 Introduction A real-time system consists of a plant where dynamic processes take place, and a controller (an embedded computer) aimed at the stabilization of the on-going processes at a required state. The controller design is especially complex, as compared with non-real-time applications, due to the reactive aspect of the its operation. This aspect comprises the need to synchronize its computations with the occurrences of the plant events (indicated by sensor data) and to accomplish their executions within hard deadlines determined by the controlled process dynamics (typical applications ..

Reasoning sbout Real-Time Reactive Systems with MASS (Extended Abstract)

) Vered Gafni Yishai Feldman Amiram Yehudai Computer Science Department Tel-Aviv University, Tel-Aviv 69978, ISRAEL PH: +972-3-6409299, FAX: +972-3-6409357, e-mail: [email protected] Abstract This paper lays the theoretical foundation for formal reasoning with the language MASS. MASS is an activation oriented specification language, suitable for specifying reactive real time systems. Following a short review of MASS, the paper presents a logical formalism based on the language of MASS events, for stating properties of MASS specifications. A version of MASS in which specified reactions must be given explicit deadlines is then shown to be decidable. The general unbounded version is shown to be undecidable. 1 Introduction MASS is an activation oriented specification language, suitable for specifying reactive real time systems. A previous paper [6] explained the basic approach, presented the language definition, showed specification examples, and outlined a semantic model for MASS..

Combining Reflection and Finite State Diagrams for Design Enforcement

This paper presents a method for design enforcement, based on a combination of reflection and State Machine Diagrams. The method is supported by RECOS, a REflective system in a Concurrent Object-oriented environment that uses Finite State Diagrams. The reflection methodology is now a developing branch in computer science for controlling and modifying systems, particularly Object-Oriented systems. RECOS is a "base-system" under which other systems can be built. Combining concepts of Concurrent Object-Oriented design, Finite State Diagrams, and reflection leads to an increase in the reliability of the systems, by insuring that objects function according to their design. RECOS also presents a safe way for handling modifications of the systems. We attempt to provide the developer of a system under RECOS with an environment that balances between easing implementation effort and guarding against unsafe implementations. We address here the issue of reflection, present the structure of RECOS, ..

Formal Development of Real-time Systems with PLOT/MASS

The paper presents a formal development process of a real-time system. We employ two related languages: the real-time logic plot for plant modeling and requirements specification, and the real-time language mass for the controller design. A deductive proof system is used to verify the design against the requirements. The examples given in the paper demonstrate the special features of the mass/plot framework that make it especially suitable for real-time systems specification. In particular, we show explicit expression of causality and timing in plot, modular design by refinement in mass, and the succinct and intuitive nature of specifications in this framework. 1 Introduction A real-time system consists of a plant where dynamic processes take place, and a controller (an embedded computer) aimed at the stabilization of the on-going processes at a required state. The plant and the controller interact through sensors that collect plant data, and actuators that are capable of affecting t..

Expression Profiling of Four Mango FT/TFL1-Encoding Genes under Different Fruit Load Conditions, and Their Involvement in Flowering Regulation

Plant flowering is antagonistically modulated by similar FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1) proteins. In mango (Mangifera indica L.), flowering is induced by cold temperatures, unless the tree is juvenile or the adult tree had a high fruit load (HFL) in the summer. Here, we studied the effects of juvenility and fruit load on the expression of four MiFT/TFL1 genes cloned from the mango ‘Shelly’ cultivar. Ectopic expression of MiFT1 in Arabidopsis resulted in early flowering, whereas over-expression of MiFT2 and the two cloned MiTFL1 genes repressed flowering. Moreover, juvenility was positively correlated with higher transcript levels of MiFT2 and both MiTFL1s. In trees with a low fruit load, leaf MiFT1 expression increased in winter, whereas HFL delayed its upregulation. MiFT2 expression was upregulated in both leaves and buds under both fruit load conditions. Downregulation of both MITFL1s in buds was associated with a decrease in regional temperatures under both conditions; nevertheless, HFL delayed the decrease in their accumulation. Our results suggest that cold temperature has opposite effects on the expression of MiFT1 and the MiTFL1s, thereby inducing flowering, whereas HFL represses flowering by both suppressing MiFT1 upregulation and delaying MiTFL1s downregulation. The apparent flowering-inhibitory functions of MiFT2 are discussed