E. Casais, "An Object-Oriented System Implementing KNOs", Proceedings of the Conference on O#ce Information Systems (COIS), pp. 284-290, Palo Alto, March 1988.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....paradigm for encapsulating knowledge and goals as knowledge objects [Tsichritzis et al. 1987] The principle idea is that KNOs are mobile, active entities that can gather information from their environment, and can exchange rules and knowledge with other KNOs. A system for defining KNOs [Casais 1988] has been implemented using the Lisp flavors package [Moon 1986] In this system, KNOs belong to one or more KNO classes, and are able to dynamically inherit parts while they execute. The operations of a KNO are encoded as production rules, each consisting of a name, a trigger condition, and a ....

E. Casais, "An Object-Oriented System Implementing KNOs", Proceedings of the Conference on O#ce Information Systems (COIS), pp. 284-290, Palo Alto, March 1988.

....objects resulting in active objects. Basically, processes operate entirely independent of each other, i.e. they are subject to truly multiple thread ofcontrol. In particular, processes may execute concurrently. In a first attempt, we associate with each active object exactly one process (see also [1, 3, 4, 2, 12, 22, 8, 9, 23, 17]) In order to indicate that objects, i.e. instances, of a certain type are active, the keyword active is utilized. Figure 4 shows the full type definition frame for active object types (the life cycle entry will be explained in the next subsection) persistent] active type htype namei ....

....active object has an owner. Thus, the general owner relationship is a forest where each passive object is a leaf. It is important to note that the owner relationship is different from the normal references relationship. The owner relationship more resembles the association of acquaintances of [8] (see also [13] which allows the cooperation of different active objects on higher level tasks. The associated acquaintances may be grouped into task specific sets, i.e. into groups of objects that cooperate to accomplish a particular task. In the context of the owner relationship such groups ....

E. Casais. An object oriented system implementing KNOs. In Proc. Conf. on Office Information Systems (COIS), pages 284--290, Palo Alto, Mar 1988.

.... p, q, q q mq p, p, q p, mq q, q, q q p, q p, m q, mq q, q, q q m p, mq p, Constantin Arapis 27 8. Related work Objects modifying their behavior dynamically, which in our model is described by objects playing different roles, has been proposed by a number of researchers[Tsic87] [Casa88] [Pern90] Hend86] Arap89] In the KNO model [Tsic87] for which a prototype system has been developed [Casa88] it is possible to specify finer grained changes of object behavior than in our model. Objects can add or drop methods during run time, as well as exchange methods among themselves. No ....

....27 8. Related work Objects modifying their behavior dynamically, which in our model is described by objects playing different roles, has been proposed by a number of researchers[Tsic87] Casa88] Pern90] Hend86] Arap89] In the KNO model [Tsic87] for which a prototype system has been developed [Casa88], it is possible to specify finer grained changes of object behavior than in our model. Objects can add or drop methods during run time, as well as exchange methods among themselves. No means are provided to control or constrain the dynamic evolution of objects. Considerations which led the ....

E. Casais. "An Object Oriented System Implementing KNOs". Proceedings of the Conference on Office Information Systems (COIS), Palo Alto, March 1988, pp. 284-290.

....description of an autonomous object includes the descriptions typical for objects, and additionally a description of the guards which we refer to in the remainder as the behavioral map of the object. This concept was strongly influenced by [2] Autonomous objects were first proposed in [17] and [20, 4] which itself are influenced by the design of the ACTORS language [1] Another implemented approach to active objects is described in [5] Recently, Liu and Mersman [16] devised an activity model for onject oriented databases. Our current approach to object activity is to view an autonomous object ....

E. Casais. An object oriented system implementing KNOs. In Proc. Conf. on Office Information Systems (COIS), pages 284--290, Palo Alto, Mar 1988.

....typical for objects, and additionally a description of the guards which we refer to in the remainder as the behavioral map of the object. This concept was strongly influenced by (Andrews, 1981) Autonomous objects were first proposed in (Nierstraz, 1987) and (Tsichritzis, et al. 1987, Casais, 1988) which itself are influenced by the design of the ACTORS language (Agha, 1986) Another implemented approach to active objects is described in (Costa, et al. 1989) Our current approach to active objects is to view an autonomous object as a strictly sequential process, that is, to have just one ....

Casais, E. (1988). An object oriented system implementing KNOs. Proc. Conf. on Office Information Systems (COIS)(pp. 284--290). Palo Alto.

....if we consider instance variables and methods themselves as values. In such a model, an object may dynamically inherit new instance variables and methods from other objects. An example of this kind of inheritance occurs in a system for distributed problem solving using knowledge objects [39][10]. Evolving active objects can acquire new rules and methods in response to events occurring in their environment. More common is scope inheritance. In this case an object s behaviour is determined in part by its environment or its acquaintances. When changes in the environment occur, the behaviour ....

E. Casais, "An Object-Oriented System Implementing KNOs," Proceedings of the Conference on Office Information Systems (COIS), pp. 284-290, Palo Alto, March 1988.

....paradigm for encapsulating knowledge and goals as knowledge objects [Tsichritzis et al. 1987] The principle idea is that KNOs are mobile, active entities that can gather information from their environment, and can exchange rules and knowledge with other KNOs. A system for defining KNOs [Casais 1988] has been implemented using the Lisp flavors package [Moon 1986] In this system, KNOs belong to one or more KNO classes, and are able to dynamically inherit parts while they execute. The operations of a KNO are encoded as production rules, each consisting of a name, a trigger condition, and a ....

E. Casais, "An Object-Oriented System Implementing KNOs", Proceedings of the Conference on Office Information Systems (COIS), pp. 284-290, Palo Alto, March 1988.

....this entails a large degree of centralized control. By contrast, our understanding of the engineering world strongly indicates that a different premise should take the place of ubiquity: object autonomy. Instead of centralized control individual objects have built in control over their fate [1, 7]. A number of characteristics augment the object autonomy paradigm, some of them inherent to it, others additional premises. Object orientation An object oriented model with the essential concepts described in [4] is adequate to model the (isolated) structure and behavior of an engineering ....

....or, if a predefined class exists, by instantiating this class. Besides instantiation new objects can be derived by cloning objects. Of course, the new object gets its own identity. Objects which are cloned are called prototype objects. 3. 3 Acquaintances An object has associated acquaintances [7] with which it cooperates on higher level tasks. The associated acquaintances may be grouped into task specific sets, i.e. into groups of objects that cooperate to accomplish a particular task. For example, an engineering object could have different sets of acquaintances with which it cooperates ....

E. Casais. An object oriented system implementing KNOs. In Proc. Conf. on Office Information Systems (COIS), pages 284--290, Palo Alto, Mar 1988.

....In this way, the object settles according to its environment. Since most problems in continuous development come from changing environments, this approach can give us a notion of automatic maintenance. Evolution of objects by changing and dynamically inheriting new methods is very promising [7]. We are talking of an elementary form of learning by apprenticeship where objects learn methods from other objects. Since the evolution of the methods is incremental several problems need to be solved. First, how can methods be dynamically inherited without creating internal object ....

E. Casais, "An Object-Oriented System Implementing KNOs," Proceedings of the Conference on Office Information Systems (COIS), pp. 284-290, Palo Alto, March 1988.

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E. Casais, "An Object-Oriented System Implementing KNOs", Proceedings COIS, ACM SIGOIS, Palo Alto, March 1988, (to appear).

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E. Casais, "An Object Oriented System Implementing KNOs," in Proceedings of the ACM Conference on Office Information Systems, pages 284--290, March 1988.

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