http://www.workflowpatterns.com/documentation/documents/yawl_qut_report_FIT-TR-2002-06.pdf

YAWL: yet another workflow language

We describe the semantics of statecharts as implemented in the STATEMATE system. This was the first executable semantics defined for the language and has been in use for almost a decade. In terms of the controversy around whether changes made in a given step should take effect in the current step or in the next one, this semantics adopts the latter approach.

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The STATEMATE semantics of statecharts

Ptolemy is an environment for simulation and prototyping of heterogeneous systems. It uses modern object-oriented software technology (C++) to model each subsystem in a natural and efficient manner, and to integrate these subsystems into a whole. Ptolemy encompasses practically all aspects of designing signal processing and communications systems, ranging from algorithms and communication strategies, simulation, hardware and software design, parallel computing, and generating real-time prototypes. To accommodate this breadth, Ptoloemy must support a plethora of widely differing design styles. The core of Ptolemy is a set of object-oriented class definitions that makes a few assumptions about the system to be modeled; rather, standard interfaces are provided for generic objects and more specialized, application-specific objects are derived from these. A basic abstraction in Ptolemy is the Domain, which realizes a computational model appropriate for a particular type of subsystem. Current examples of domains include synchronous and dynamic dataflow, discrete-event, and others appropriate for control software and embedded microcontrollers. Domains can be mixed as appropriate to realize and overall system simulation. Some current applications of Ptolemy include networking and transport, call-processing and signaling software, embedded microcontrollers, signal processing (including implementation in real-time), scheduling of parallel digital signal processors, board-level hardware timing simulation, and combinations of these.

/pdf/ptolemy-a-framework-for-simulating-and-prototyping-50cl496a5h.pdf

Ptolemy: a framework for simulating and prototyping heterogeneous systems

Based on a rigorous analysis of existing workflow management systems and workflow languages, a new workflow language is proposed: yet another workflow language (YAWL). To identify the differences between the various languages, we have collected a fairly complete set of workflow patterns. Based on these patterns we have evaluated several workflow products and detected considerable differences in their ability to capture control flows for non-trivial workflow processes. Languages based on Petri nets perform better when it comes to state-based workflow patterns. However, some patterns (e.g. involving multiple instances, complex synchronisations or non-local withdrawals) are not easy to map onto (high-level) Petri nets. This inspired us to develop a new language by taking Petri nets as a starting point and adding mechanisms to allow for a more direct and intuitive support of the workflow patterns identified. This paper motivates the need for such a language, specifies the semantics of the language, and shows that soundness can be verified in a compositional way. Although YAWL is intended as a complete workflow language, the focus of this paper is limited to the control-flow perspective.

While message sequence charts (MSCs) are widely used in industry to document the interworking of processes or objects, they are expressively weak, being based on the modest semantic notion of a partial ordering of events as defined, eg, in the ITU standard A highly expressive and rigorously defined MSC language is a must for serious, semantically meaningful tool support for use-cases and scenarios It is also a prerequisite to addressing what we regard as one of the central problems in behavioral specification of systems: relating scenario-based inter-object specification to state-machine intra-object specification This paper proposes an extension of MSCs, which we call live sequence charts (or LSCs), since our main extension deals with specifying “liveness”, ie, things that must occur In fact, LSCs allow the distinction between possible and necessary behavior both globally, on the level of an entire chart and locally, when specifying events, conditions and progress over time within a chart This makes it possible to specify forbidden scenarios, for example, and enables naturally specified structuring constructs such as subcharts, branching and iteration

/pdf/lscs-breathing-life-into-message-sequence-charts-1jwdnvm56w.pdf

LSCs: Breathing Life into Message Sequence Charts

STATEMATE is a set of tools, with a heavy graphical orientation, intended for the specification, analysis, design, and documentation of large and complex reactive systems. It enables a user to prepare, analyze, and debug diagrammatic, yet precise, descriptions of the system under development from three interrelated points of view, capturing structure, functionality, and behavior. These views are represented by three graphical languages, the most intricate of which is the language of statecharts, used to depict reactive behavior over time. In addition to the use of statecharts, the main novelty of STATEMATE is in the fact that it understands the entire descriptions perfectly, to the point of being able to analyze them for crucial dynamic properties, to carry out rigorous executions and simulations of the described system, and to create running code automatically. These features are invaluable when it comes to the quality and reliability of the final outcome. >

/pdf/statemate-a-working-environment-for-the-development-of-1w9uawvlqd.pdf

STATEMATE: a working environment for the development of complex reactive systems

We describe how statecharts are used to model the behavior of complex reactive systems. The paper is divided into two parts, according to the two main ways that have been suggested for modeling the structure of such systems: structured analysis (SA) and object-orientation (OO). It uses a cardiac pacemaker example for illustration. (This paper available in hard-copy only.)

Statecharts in Use: Structured Analysis and Object-Orientation

STATEMATE: A Working Environment for the Development of Complex Reactive Systems Manuscript received May 12, 1988; revised November 13, 1989. Recommended by L. A. Belady. This work was supported in part by the Bird Foundation and the Israel Ministry of Industry and Commerce. IEEE Log Number 8933740. STATEMATE is a registered trademark of i-Logix, Inc.

Boris Abramovich Trakhtenbrot (20.02.1921– 19.09.2016), the centenary of whose birth was celebrated on 20 February 2021, was one of the founders of theoretical computer science, who was widely recognised both in the Soviet Union and all over the world. His scientific biography is also interesting in both its humanistic and historical aspects. He was born on 20 February 1921 in Bessarabia, in the village of Brichevo (which during various periods of time belonged to Russia, Romania, USSR, and Moldova). In 1940 he started studying mathematics at the Kishinev Pedagogical Institute (now Ion Creangă State Pedagogical University). At the beginning of World War II he was evacuated to the Urals with the Institute. By that time Kishinev was already under bombardment. Until 1943 he was completely out of touch with his family, which was separated and deported from Bessarabia to the Urals and Siberia during the large-scale eviction in June of 1941 (paradoxically, this exile saved his family from the Holocaust). Trakhtenbrot was disqualified from active military service because of his weak eyesight. During that period he combined intermittent studies with working at a footwear factory and in a gas trust company. In 1944 he returned from evacuation. For a year he worked as a teacher of mathematics in the town of Beltsy (now Moldovan Bălţi). He completed his mathematical studies at the University of Chernovtsy (now Ukrainian Chernivtsi) in 1945–1947. Parallel to his studies, he took an active part in the restoration of the well-stocked mathematical library of Chernovtsy State University, and this activity played an important role in his education and familiarization with science. A number of teachers at Chernovtsy State University were disciples of Moscow mathematical schools. Among those who had great influence on Trakhtenbrot was A.A. Bobrov, a former student of A. N. Kolmogorov. It was at Bobrov’s seminar on Hausdorff’s monograph that Trakhtenbrot became fascinated by descriptive set theory. On the

Boris Abramovich Trakhtenbrot

This memorial paper tells the story of the beginning of Boris (Boaz) Trakhtenbrot's long and rich life path, full of unusual and sometimes tragic events. This path led a boy from a Jewish settlement in Eastern Europe to be recognized as one of the founding fathers of theoretical computer science.

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Mark B. Trakhtenbrot

Papers

STATEMATE: a working environment for the development of complex reactive systems

Statecharts in Use: Structured Analysis and Object-Orientation

Boris Abramovich Trakhtenbrot

Boris (Boaz) Trakhtenbrot - The Beginning