Lalita Jategaonkar Jagadeesan

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We extend a fragment of the programming language Standard ML by incorporating a more general form of record pattern matching and providing for user-declared subtypes. Together, these two enhancements may be used to support a restricted object-oriented programming style. In keeping with the framework of Standard ML, we present typing rules for the language,(More)
We study in this paper the problem of analyzing implementations of open systems --- systems in which only some of the components are present. We present an algorithm for automatically closing an open concurrent reactive system with its most general environment, i.e., the environment that can provide any input at any time to the system. The result is a(More)
ESTEREL is a formally-defined language designed for programming reactive systems; namely, those that maintain a permanent interaction with their environment. The AT&T 5ESS R telephone switching system is an example of a legacy reactive system. As a case study, we describe an implementation in ESTEREL of one feature of a 5ESS switch; this implementation has(More)
Testing commercial software is expensive and time consuming. Automated testing methods promise to save a great deal of time and money throughout the software industry. One approach that is well-suited for the re-active systems found in telephone switching systems is speciication-based testing. We have built a set of tools to automatically test software(More)
We describe the application of model checking tools to analyze a real-time software challenge in the design of Lucent Technologies' 5ESS telephone switching system. We use two tools: COSPAN for checking real-time properties , and TPWB for checking probabilistic specifications. We report on the feedback given by the tools, and based on our experience,(More)
We present a technique for automatically verifying linear-time temporal logic safety properties of programs written in ESTEREL, a formally-defined language for programming reactive systems. In our approach, linear-time temporal logic safety properties are first translated into ESTEREL programs that model these properties. Using the ESTEREL compiler, the(More)
Modern interactive services such as information and e-commerce services are becoming increasingly more flexible in the types of user interfaces they support. These interfaces incorporate automatic speech recognition and natural language understanding, and include graphical user interfaces on the desktop and web-based interfaces using applets and HTML forms.(More)
Numerous formal specification methods for reactive systems have been proposed in the literature. Because the significant differences between the methods are hard to determine, choosing the best method for a particular application can be difficult. We have applied several different methods, including Modechart, VFSM, ESTEREL, Basic LOTOS, Z, SDL and C, to an(More)