Conventional Object-oriented Model Research Articles

A development method of time‐triggered object‐oriented software for embedded control systems

AbstractThis paper describes a time‐triggered object‐oriented model for embedded control systems and a control software development method based on that model. Conventional object‐oriented models had been based on event‐triggered actions. In contrast, we propose a time‐triggered object‐oriented model for real‐time control. This model, which consists of a set of objects for calculating data values required for control, activates these objects cyclically to implement time‐triggered actions. This paper also shows that a distributed control system having location transparency can be implemented efficiently according to this model. In addition, we propose a control software development method based on the proposed time‐triggered object‐oriented model. This development method can extract objects according to simple operations from control block diagrams used to describe control specifications. This paper also introduces an embedded system‐oriented implementation method that does not consume much resource and presents an application example in a distributed control system for automobiles. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(2): 43–54, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1189

Multifaceted object modeling with roles: A comprehensive approach

In conventional object-oriented database systems, it is assumed silently that fundamental object types and inter-object relationships can be classified statically, prescribing basic structural and behavioral properties for all the objects in the database. Such a classification-based approach falls short of supporting emerging data-intensive applications requiring more advanced dynamic capabilities. One of such advanced capabilities is the support of modeling subjectivity – the ability to (among others) provide multiple perspectives of application objects or to model so-called `multifaceted objects' which, on different stages, can exhibit different forms and behavior. This article describes an extended object-oriented approach that we have been investigating for this purpose. Advanced features embodied by dynamic and versatile role facilities have been introduced into a conventional object-oriented model, which facilitates specifying and modeling such applications in a natural, incremental and systematic way. Examples from automated manufacturing systems have been used to examine the necessity and utility of such advanced role facilities, and experimental prototype systems of the role mechanism have also been developed by exploiting different techniques and approaches of implementing roles.

EAMMO: an environmental agent model for multiple objects

Many conventional object-oriented models suffer problems in the representation of multiple objects. A multiple object is an object with multiple aspects, autonomy, and pro-activeness. This paper proposes a new agent model which applies the agent-oriented paradigm to represent multiple objects. This agent model consists of three types of agents as follows: (1) an upper-agent which describes an autonomous and dynamic object; (2) a lower-agent which describes a reactive and static object; and (3) an environmental-agent which describes the environment of the other agents. As an example, we model soccer players (a kind of multiple objects) in EAMMO. Three kinds of soccer agents are constructed with different powers. We simulate the soccer games to confirm the effectiveness of our model.

An object deputy model for realization of flexible and powerful objectbases

In object-oriented databases, data and methods are combined by objects and their classes. Information redundancies are removed by the notions of class hierarchy and inheritance. This contributes the realization of high-performance systems. However, the flexibility of object structures still remains a problem due to its encapsulation feature. In this paper, we introduce an object deputy model which extends conventional object-oriented models with the concepts of deputy objects and deputy classes. A deputy object has its own identifier and may possess its own attributes and methods. It can also have attributes that are computed from values stored within its source object, and can be associated with methods generated from these of the source object. The inheritances are realized by switching operations, which make it possible to realize controllable, selective and dynamic inheritance structures. Schemata of deputy objects are defined by deputy classes which can be derived by an object deputy algebra. An object can have many deputy objects, and several objects can share a single deputy object. Thus, objects can be indirectly divided and combined through their deputy objects. We show that several difficult database problems, such as flexible views, objects with more than one role, object migration, and multiple inheritance become much easier in this model. The data-knowledge coordination model developed for the integration of distributed databases and knowledge-bases can also be realized easily by the object deputy model. Finally, we discuss several advanced database applications of this model, such as geographic databases, virtual office systems, and distant education systems.