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Modeling with UML and Its Real-Time Profiles
Published in Katalin Popovici, Pieter J. Mosterman, Real-Time Simulation Technologies, 2017
Emilia Farcas, Ingolf H. Krüger, Massimiliano Menarini
The first step for understanding UML behavioral semantics is defining how behavior is specified and which elements participate in an instance of such behavior. UML specifies behavior by defining flows of actions. These flows are always attached to a structural element, a Classifier. UML distinguishes between two types of objects with behavior: active and passive. Active objects, on the one hand, are the source of behavior. When created, they execute their actions independently of any other object. Passive objects, on the other hand, execute their actions in reaction to requests from other objects. Active objects subsume familiar programming concepts such as threads of execution and processes. The UML specification uses this more generic representation so that it can include behavior of entities that are not necessarily programs (e.g., people).
A
Published in Phillip A. Laplante, Dictionary of Computer Science, Engineering, and Technology, 2017
active object an object instantiated from an active class. An active object presents a given degree of autonomy and is typically responsible for the activities of other objects. In object-oriented systems, active objects produce asynchronous actions without the stimulation of other objects. Typically, in software applications there exist only few active objects managing all the other application objects. These can be pure passive or may present a certain degree of autonomy. In some texts, the non-pure active objects are considered active objects as well. A high number of active objects identify a high degree of parallelism for the application producing problems of synchronization.
Embedded Software Modeling and Design
Published in Louis Scheffer, Luciano Lavagno, Grant Martin, EDA for IC System Design, Verification, and Testing, 2018
In this task-centric approach, the behavior of each active object or task consists of a combination of reading input signals, performing computation, and producing output signals (Figure 9.28, left). Each active object can request the execution of actions of other passive objects in a synchronous or asynchronous fashion.
Modeling, analysis and verification of real-time resource access control protocols: a formal approach
Published in International Journal of Computers and Applications, 2018
Rumpa Hazra, Shouvik Dey, Jayashree Singha
The proposed formal specification is based on the concept that sequence diagrams have the basic components such as set of active objects (actors and objects) and when some specific event (denoted by event) occurs for a particular active object, an edge is drawn from this active object to another active object (denoted by act_obj) in order toestablish an association between them. Now, these events may occur based on some specific conditions which when satisfied then only association takes place between the active objects and also there may exists some alternatives of the choice of active objects for the association.