Adaptive laser link reconfiguration using constraint propagation

This paper describes Harris AI research performed on the Adaptive Link Reconfiguration (ALR) study for Rome Lab, and focuses on the application of constraint propagation to the problem of link reconfiguration for the proposed space based Strategic Defense System (SDS) Brilliant Pebbles (BP) communications system. According to the concept of operations at the time of the study, laser communications will exist between BP's and to ground entry points. Long-term links typical of RF transmission will not exist. This study addressed an initial implementation of BP's based on the Global Protection Against Limited Strikes (GPALS) SDI mission. The number of satellites and rings studied was representative of this problem. An orbital dynamics program was used to generate line-of-site data for the modeled architecture. This was input into a discrete event simulation implemented in the Harris developed COnstraint Propagation Expert System (COPES) Shell, developed initially on the Rome Lab BM/C3 study. Using a model of the network and several heuristics, the COPES shell was used to develop the Heuristic Adaptive Link Ordering (HALO) Algorithm to rank and order potential laser links according to probability of communication. A reduced set of links based on this ranking would then be used by a routing algorithm to select the next hop. This paper includes an overview of Constraint Propagation as an Artificial Intelligence technique and its embodiment in the COPES shell. It describes the design and implementation of both the simulation of the GPALS BP network and the HALO algorithm in COPES. This is described using a 59 Data Flow Diagram, State Transition Diagrams, and Structured English PDL. It describes a laser communications model and the heuristics involved in rank-ordering the potential communication links. The generation of simulation data is described along with its interface via COPES to the Harris developed View Net graphical tool for visual analysis of communications networks. Conclusions are presented, including a graphical analysis of results depicting the ordered set of links versus the set of all possible links based on the computed Bit Error Rate (BER). Finally, future research is discussed which includes enhancements to the HALO algorithm, network simulation, and the addition of an intelligent routing algorithm for BP

A Conceptual Model for Negotiating in Service-Oriented Environments

Web services have been developed in recent years as a fundamental technique for the new generation of B2B or EAI applications. For their getting more available that imposes a new vision of service-oriented computing, the software industry has shifted its attention on software from developing a product as required to delivering a service on demand. In order to gain the many benefits from such a service-oriented model of software, several critical issues need to be addressed in a service-oriented environment such as differentiation of services with multiple attributes, dynamic selection and provision of services in a supply chain style, and commitment of services with prescribed rules. From the perspective of management, these issues are concerned within a process of negotiating desired services in a service-oriented environment. In this paper, we propose an object-oriented model that specifies such a negotiation process with explicit constructs addressing these critical issues. The model contains an architecture diagram that describes required components and their interactions for fulfilling the negotiation process, as well as a class/sequence diagram that specifies in detail what class objects these components have in order to collaboratively support all required behaviors occurred within the negotiation process

On the Conversion of Program Specifications into Pseudo Code using Jackson Structured Programming

In this paper, we present a technique to automatically translate program specifications into pseudo code. This technique is developed in the context of the well-known programming method Jackson Structured Programming (JSP). The objective of our research is to investigate to what extent a programming method can be automated. Current CASE tools are only able to automate programming methods to a very limited extent, whereas our technique automates the entire programming cycle by creating pseudo code from program specifications. We show that the JSP programming method can be transformed into a set of formal rules when the scope of the technique is limited to a well-defined area of problems. The rules are implemented in a CASE tool, called JSPTool, which is currently operative, although still in a prototyping phase. We believe that the strength of the CASE tool lies in the fact that it is able to automate the programming process completely, although its scope possibly is still rather limited. In this paper, the technique is explained by solving an example programming problem. The source language that has been developed to enter program specifications is briefly explained. Also, the differences between other JSP CASE tools and JSPTool are dealt with. Some additional features of the method are discussed and suggestions for future research are given

Next generation software environments : principles, problems, and research directions

The past decade has seen a burgeoning of research and development in software environments. Conferences have been devoted to the topic of practical environments, journal papers produced, and commercial systems sold. Given all the activity, one might expect a great deal of consensus on issues, approaches, and techniques. This is not the case, however. Indeed, the term "environment" is still used in a variety of conflicting ways. Nevertheless substantial progress has been made and we are at least nearing consensus on many critical issues.The purpose of this paper is to characterize environments, describe several important principles that have emerged in the last decade or so, note current open problems, and describe some approaches to these problems, with particular emphasis on the activities of one large-scale research program, the Arcadia project. Consideration is also given to two related topics: empirical evaluation and technology transition. That is, how can environments and their constituents be evaluated, and how can new developments be moved effectively into the production sector

Steps Towards a Method for the Formal Modeling of Dynamic Objects

Fragments of a method to formally specify object-oriented models of a universe of discourse are presented. The task of finding such models is divided into three subtasks, object classification, event specification, and the specification of the life cycle of an object. Each of these subtasks is further subdivided, and for each of the subtasks heuristics are given that can aid the analyst in deciding how to represent a particular aspect of the real world. The main sources of inspiration are Jackson System Development, algebraic specification of data- and object types, and algebraic specification of processes

An object-oriented analysis method for customer relationship management information systems

Abstract For the advances of Internet technologies in recent years, Electronic Commerce (EC) has gained many attentions as a major theme for enterprises to keep their competitiveness. Amongst all possibly desired endeavors for the EC, research has shown that effective management of customer relationships is a major source for keeping competitive differentiation. Therefore, it is commonly recognized as an important goal for an enterprise to promote its management of customer relationships through a prospect information system on the Internet to achieve the so-called Business-to-Customer EC. In this paper, we propose an object-oriented analysis method for the development of such a Customer Relationship Management Information System (CRMIS). The approach starts from the identification of prospect customers and their desired behaviors under preferable execution environments, and ends with the specification of system-internal objects/entities that collaborate to satisfy these behaviors and environments. The method is a use case driven approach with UML utilized and extended as its tool. To illustrate, the method is applied to an exemplified CRMIS for house agency

The Algebraic Framework for Object-Oriented Systems

Category Theory is introduced as the mathematical model for object-oriented systems which are distributed, heterogeneous, real-time, embedded, and open-ended. Each object can be represented as an algebra. A collection of algebras with morphisms form a category if they satisfy some conditions. After a brief introduction of categorical concepts which are needed to formulate the framework for object-oriented systems, they are explicated in terms of objects. Then some system design methodologies such as SADT, JSD, MASCOT 3, OOD, HOOD, MOON, ADM 3, and Petri nets are examined in the categorical framework and classified into four groups: functional, process-based, object-oriented, and net-based. Combining theoretical and practical results, the interactive system design tool OBJ-NET is briefly introduced.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43097/1/10952_2004_Article_183735.pd

Bridging Technical Spaces: Model Translation from TA to XMI and Back Again

There are many different techniques and notations for extracting architecturally interesting information from the source code of existing software systems. This process is known as reverse engineering. One current problem with reverse engineering techniques is that models of software systems cannot easily be transferred from one notation and storage format to another. We refer to this as the problem of bridging technical spaces. In this work, we approach the issue of bridging between the SWAG technical space and the UML technical space. The SWAG technical space, named after the Software Architecture Group at the University of Waterloo, consists of fact extractors, fact manipulators, schemas, and a fact storage language - the Tuple-Attribute language (TA). The UML technical space consists of the UML metamodel, the XML Metadata Interchange (XMI) format for encoding UML models, and various UML modeling tools. We have designed and implemented a plugin for MagicDraw UML, which will import, export, and merge between XMI-encoded UML models and TA-encoded Function-Level Schema models. We document evidence of what is referred to as a Bridge Domain - a technical space which exists between two encodable spaces. The metamodels of the two notation languages that we have focused on are very rich and flexible, but neither technical space is capable of fully expressing an accurate architectural model of any given software system; however, each technical space is capable of maintaining certain semantic information relevant to that technical space through multiple merge operations

A Method for Specifying Complex Real-Time Systems With Application to an Experimental Variable Stability Helicopter

Engineering systems increasingly contain a significant element of embedded software. The specification of such systems causes problems because of the diversity of the sub-systems which they contain. For example, in modem aerospace systems a combination of mechanical, electrical, hydraulic and digital sub-systems need to function together in a safety-critical manner. The need is for a uniform means of specification which spans the whole diversity of sub-systems and which serves both to verify and to validate the functional aspects of the total system

Rechnerunterstützung für die konzeptuelle Modellierung

Ein konzeptuelles Modell ist eine stark abstrahierte Darstellung eines Ausschnittes der realen Welt. Viele der bekannten Modelliertechniken geben nur eine Sicht des Weltausschnittes wieder. Für die Verwendung von konzeptuellen Modellen z.B. in der Analysephase der Software-Entwicklung müssen allerdings mehrere Sichten betrachtet werden. Die Diskussion über verschiedene Basistechniken sowie kombinierte und objekt-orientierte Modelliertechniken ergibt, daß es wünschenswert ist, nacheinander mehrere Modelle mit unterschiedlichen Techniken zu erstellen und die Teilmodelle zu einem konsistenten Gesamtmodell zu integrieren. Durch den Einsatz rechner-gestützter Werkzeuge (CASE-Tools) kann der Modellierer bei der Anwendung einzelner Modelliertechniken in vielerlei Hinsicht unterstützt werden. Zur Unterstützung des Integrationsprozesses werden mehrere Werkzeuge zu einem Modelliersystem (I-CASE-Systeme) zusammengefaßt, wobei die Art und die Zahl der in einem Modelliersystem verwendeten Werkzeuge festgelegt ist und nicht vom geplanten Verwendungszweck der konzeptuellen Modelle abhängig gemacht werden kann. Durch die Standardisierung von Repository-Schnittstellen (IRDS, Repository Manager, etc.) konnten offene d.h. erweiterbare Modelliersysteme entwickelt werden. Aufgrund der unbekannten Zusammensetzung solcher offenen Systeme ist es aber schwierig, Funktionen für die Integration von (mit verschiedenen Werkzeugen erstellten) Teilmodellen bereitzustellen. Als Lösungsvorschlag für ein sowohl erweiterbares als auch integrierendes Modelliersystem werden in dieser Arbeit der Aufbau und die Funktionsweise von C-CASE-Systemen (Configurable-CASE-Systeme) vorgestellt. Diese neue Art von Modelliersystemen besteht aus einem generischen Modelliereditor, einem semantischen Repository und einer Integrationsfunktionalität. Alle drei Komponenten müssen vor dem Einsatz des Systems konfiguriert werden. Sie können aber auch nachträglich neu konfiguriert werden, wenn z.B. eine zusätzliche Modelliertechnik eingesetzt werden soll