Kenneth S. Rubin

Object behavior analysis

Object Behavior Analysis nalysis is the study and modeling of a given problem domain, within the context of stated goals and objectives. It focuses on what a system is supposed to do, rather than how it is supposed to do it (which we consider the design aspects). In addition , it must embody the rule of traceability (why), which justifies the existence of a given result by tying it back to the stated goals and objectives. The components of the problem domain can be described as anything that end users of the system, both humans and machines, view as part of the problem context. This may include technical issues, if the users view such issues as part of the problem. • • • • • • • • • • • • • • • • We want the analysis process to be carried out in a predictable and controllable manner. In taking an object-oriented approach to analysis , our goal on completion is that we have a clear understanding of the behaviors exhibited by the system , the objects that exhibit these behaviors, the relationships among the objects, and how the objects interact with one another (the system dynamics). This must all be specified in a clear and well-defined language of object and behavior names, chosen from the problem domain. In addition, any implementation code must be traceable back to the results of the analysis. This means that the vocabulary and structures apparent in the design and implementation must clearly reflect the vocabulary and structures that result from the analysis. Object-oriented analysis endeavors to model a situation in terms of a collection of interacting entities, each of which provides a well-defined set of behaviors and attributes. Most published approaches describe conceptually similar definitions , although they adopt alternate terminologies [2, 3, 10]. There is a high degree of agreement on the desired structure of the end result; we differ in how to get to the end result. Many approaches recommend first searching for the tangible objects , notably seeking the nouns in a requirements specification and any applicable verbs and adjectives. With nouns as the objects, the message interface is determined from the verbs, and the logical properties are derived from the adjectives. Although this basic approach may work for small systems, it is our experience that it simply will not scale up. First, it assumes that a complete, …

OFMspert: inference of operator intentions in supervisory control using a blackboard architecture

The authors proposes an architecture for an expert system that can function as an operators associate in the supervisory control of a complex dynamic system. Called OFMspert (operator function model (OFM) expert system), the architecture uses the operator function modeling methodology as the basis for the design. The authors put emphasis on the understanding capabilities, i.e. the intent referencing property, of an operators associate. They define the generic structure of OFMspert, particularly those features that support intent inferencing. They also describe the implementation and validation of OFMspert in GT-MSOCC (Georgia Tech-Multisatellite Operations Control Center), a laboratory domain designed to support research in human-computer interaction and decision aiding in complex, dynamic systems. >

ALLY: an operator's associate for cooperative supervisory control systems

The design, implementation, and evaluation of ALLY, a computer-based associate for the human supervisor of a simulated satellite ground control system, is described. ALLYs dynamic intent inferencing abilities and system control properties are described. Experimental evaluation of ALLY compared performance of a two-person team with a person-ALLY team in the control of a simulated satellite ground control system. >

Validation of intent inferencing by a model-based operator's associate

OFMspert (Operator Function Model expert system) is an architecture for an intelligent operators associate. The function of such an associate is to provide intelligent assistance for the human operator of a complex dynamic system. The basis for intelligent, context-sensitive advice and reminders is the ability of the associate to infer likely operator intentions in real time. This paper describes the implementation and validation of OFMsperts intent inferencing capability. In particular, a two-stage methodology for validation is proposed. This methodology is then used in the experimental validation of OFMsperts intent inferencing.

Reuse in software engineering: an object-oriented perspective

The role of reuse within software engineering is examined. The benefits of reuse are stated, inhibitors to successful reuse are pointed out, and technical issues for achieving reuse are examined. Specific attention is paid to how object-oriented software engineering enhances or reduces the potential for reuse as compared with traditional (i.e. not based on objects or object-oriented concepts) software engineering. Three major activities for supporting reuse are described. The first is the intentional development of reusable artifacts, the second is the representation and classification of artifacts into repositories, and the last is the utilization of the artifacts from repositories. The object-oriented model is found to be significantly similar to the traditional model in many aspects. However, differences are found insofar as object-oriented design supports the design techniques of abstraction and factorization, which utilize object inheritance to yield reusable objects.<<ETX>>

Intent Inferencing with a Model-Based Operator’s Associate

This paper describes a portion of the OFMspert (Operator Function Model Expert System) research project. OFMspert is an architecture for an intelligent operator’s associate or assistant that can aid the human operator of a complex, dynamic system. Intelligent aiding requires both understanding and control. This paper focuses on the understanding (i.e., intent inferencing) ability of the operator’s associate. Understanding or intent inferencing requires a model of the human operator; the usefulness of an intelligent aid depends directly on the fidelity and completeness of its underlying model. The model chosen for this research is the operator function model (OFM) (Mitchell, 1987). The OFM represents operator functions, subfunctions, tasks, and actions as a heterarchic-hierarchic network of finite state automata, where the arcs in the network are system triggering events. The OFM provides the structure for intent inferencing in that operator functions and subfunctions correspond to likely operator goals and plans. A blackboard system similar to that of HASP (Nii et al., 1982) is proposed as the implementation of intent inferencing function. This system postulates operator intentions based on current system state and attempts to interpret observed operator actions in light of these hypothesized intentions.

ALLY: an operator's associate model for cooperative supervisory control situations

The authors explore the key characteristics of an intelligent advisory system. A central feature is that human-machine cooperation should be based on a metaphor of human-to-human cooperation. ALLY, a computer-based operators associate, is discussed which is based on a preliminary theory of human-to-human cooperation. ALLY assists the operator in carrying out the supervisory control functions for a simulated NASA ground control system. Experimental evaluation of ALLY indicates that operators using ALLY performed at least as well as they did when using a human associate, and in some cases they performed even better.<<ETX>>

A smalltalk implementation of an intelligent operator's associate

This paper describes the use of Smalltalk in the design and implementation of OFMspert. OFMspert is an architecture for an intelligent operators associate. In order to verify the architecture, an OFMspert was implemented to act as an assistant to an operator of a NASA satellite ground control system. OFMspert is a large system that utilizes a Smalltalk implementation of a knowledge-based problem solving method known as the blackboard architecture. The entire system was designed and implemented in Smalltalk/V™ and later ported to the Smalltalk-80™ system. The object-oriented paradigm in general, and Smalltalk‡ in particular, greatly facilitated the rapid design and implementation of this system. This paper summarizes the OFMspert architecture, emphasizing its implementation in an object-oriented paradigm.

Object-oriented project management (abstract)

Object-oriented projects have to be managed properly to obtain the most benefits from object-oriented technology. This tutorial explains the effect of object-oriented technology on costs, staffing ...