Tactical-level onboard real-time advisory expert systems for manned aircraft as development and maintenance entities

Tactical-level onboard intelligent systems support the crew’s decision-making concerning real-time targeting and determining the way of achieving real-time-assigned targets (tactical objectives). The classification and image of intelligent systems and their interactions with the crew and between each other, as well as knowledge of the replenishment procedures in the course of operation, are presented.     

Towards generative expert systems for architectural detailing

This paper presents an approach to generative expert systems for architectural detailing based on design grammars and knowledge engineering. Design grammars are based on transformation rules operating on patterns: Knowledge engineering provides the mechanism to drive design grammars in the form of expert systems and the means of including knowledge about design states in the process of achieving solutions. A worked example for the production of eaves' details is presented. The implications of the availability of such systems are discussed.     

A fault-tolerant architectural approach for dependable systems

A system's structure enables it to generate its intended behavior from its components' behavior. A well-structured system simplifies relationships among components, which can increase dependability. With software systems, the architecture is an abstraction of the structure. Architectural reasoning about dependability has become increasingly important because emerging applications are increasingly complex. We've developed an architectural approach for effectively representing and analyzing fault-tolerant software systems. The proposed solution relies on exception handling to tolerate faults associated with component and connector failures, architectural mismatches, and configuration faults. Our approach, a specialization of the peer-to-peer architectural style, hides inside the architectural elements the complexities of exception handling and propagation. Our goal is to improve a system's overall reliability and availability by making it tolerant of nonmalicious faults.     

Use of complex variables for the solution of certain nonlinear systems

The paper discusses several practical aspects of a method for tackling nonlinear differential equations. The method has probably been known to workers in quantum mechanics, but it does not seem to have been employed in applied mechanics and engineering. It relies on the possibility of lumping together pairs of differential equations, e.g. in cases where the original system equations exhibit certain symmetry which permits the transformation of pairs of real variables to complex variables. Under certain conditions this transformation procedure provides a relatively simple analytical tool for the integration of complicated sets of nonlinear differential equations; under less favorable conditions a numerical procedure is also involved in the final integration. The implementation of this “complex procedure” in computer integration is worthwhile since the associated coding of the systems and the computer programs are more compact and consequently simpler. It is also shown that the widely used method for the approximate solution of nonlinear differential equations — the “averaging method” — yields equations which can be tackled by the procedure. A short review of the averaging method is presented in order to demonstrate that the complex procedure can be involved in the averaging method both at the stage of the derivation of the approximate system equations and at the stage of integration of these equations. The employment of the complex procedure leads to improvements at both stages.The improvements gained by applying the complex procedure in association with the averaging method are more significant the larger the system is and the more pairs of variables susceptible for the suggested procedure it contains. The paper therefore concludes with a review of large electromechanical, biological and physiological systems where the employment of the complex procedure may lead to a considerable simplification of calculations.     

Explaining employees' Extended Use of complex information systems

Investments in complex information systems by organizations reached a record high of U.S.$26.7 billion in 2004. Yet, organizations seldom use these systems to the fullest extent and attain the expected return on investment. This paper addresses the issue of system underutilization by investigating Extended Use, which refers to using more system features to support one's tasks. Extended Use was examined in the nomological networks of the IS Continuance (ISC) Model and Technology Acceptance Model (TAM). A field survey was conducted in a large manufacturing firm that had successfully implemented a popular enterprise resource planning solution for more than 2 years. All paths in both ISC and TAM were statistically significant. A synthesized model was later proposed and examined in a post hoc analysis. The results indicate that the synthesized model, as compared to ISC and TAM, explained slightly higher variances in Extended Use, Perceived Usefulness (PU), and Satisfaction. Specifically, both Perceived Ease of Use (PEOU) and PU both affected Extended Use. Interestingly, Satisfaction has no direct impact on Extended Use in the presence of PU and PEOU. In contrast to most technology acceptance research, PEOU has a stronger behavioral impact than that of PU. This research provides a framework that explains Extended Use and is one of the few studies that investigates IS use behavior that exceeds simple, shallow, and routine use.     

Bacterial colonies as complex adaptive systems

The present work explores bacterial colonies and their individual and social behaviours under the lens of complex adaptive systems. We initially provide a background on the biology of bacteria to describe important phenomena, such as quorum-sensing, individual and collective behaviours, adaptation, evolution and self-organization over the influence of mechanical effects on bacterial systems and connecting scales. We then explore some associations between bacterial colonies and complex adaptive systems by considering components and ownerships of self-organization. The main contribution of this paper places emphasis on individual decision-making and behaviour as a cause of bacterial colonies’ actions, i.e., how self-organization and collective behaviours impact the ability of a bacterial colony to address an environmental stimulus and maintain itself as an open biological and fault-tolerant system. Finally, we conclude the work and provide some comments regarding future research.     

An architectural application framework for evolving distributed systems

In this paper, we present an object-oriented application framework to support the development of evolving distributed systems. The framework combines concepts of the object-oriented paradigm with those of architectural design. The result is a framework which supports extensible and reusable configurations of distributed components. The framework addresses the problem of evolution by allowing the addition, replacement and extension of components of a configuration. Evolution is also possible at run time, where a configuration can change dynamically depending on a particular event. The paper outlines the fundamental aspects of our framework and presents a case study, which illustrates its application.     

A SysML-based methodology for mechatronic systems architectural design

Mechatronic systems are characterized by the synergic interaction between their components from different technological domains. These interactions enable the system to achieve more functionalities than the sum of the functionalities of its components considered independently. Traditional design approaches are no longer adequate and there is a need for new synergic and multidisciplinary design approaches with close cooperation between specialists from different disciplines.SysML is a general purpose multi-view language for systems modeling and is identified as a support to this work.In this paper, a SysML-based methodology is proposed. This methodology consists of two phases: a black box analysis with an external point of view that provides a comprehensive and consistent set requirements, and a white box analysis that progressively leads to the internal architecture and behavior of the system.     

基于本体的软件密集型系统架构知识管理研究

为了解决架构知识蒸发的问题,提出了一种基于本体的架构知识管理框架。分析了该架构知识的分类,在此基础上从架构问题、架构设计决策和软件架构等3方面构建一个架构知识本体模型,并且描述了这3类架构知识的内涵及其相互关系,进而提出一个架构知识管理框架,能覆盖架构知识获取、编档、评价、存储和复用等过程,实现了架构知识的全面管理、共享和复用。     

An architectural model for software testing lesson learned systems

ContextSoftware testing is a key aspect of software reliability and quality assurance in a context where software development constantly has to overcome mammoth challenges in a continuously changing environment. One of the characteristics of software testing is that it has a large intellectual capital component and can thus benefit from the use of the experience gained from past projects. Software testing can, then, potentially benefit from solutions provided by the knowledge management discipline. There are in fact a number of proposals concerning effective knowledge management related to several software engineering processes.ObjectiveWe defend the use of a lesson learned system for software testing. The reason is that such a system is an effective knowledge management resource enabling testers and managers to take advantage of the experience locked away in the brains of the testers. To do this, the experience has to be gathered, disseminated and reused.MethodAfter analyzing the proposals for managing software testing experience, significant weaknesses have been detected in the current systems of this type. The architectural model proposed here for lesson learned systems is designed to try to avoid these weaknesses. This model (i) defines the structure of the software testing lessons learned; (ii) sets up procedures for lesson learned management; and (iii) supports the design of software tools to manage the lessons learned.ResultsA different approach, based on the management of the lessons learned that software testing engineers gather from everyday experience, with two basic goals: usefulness and applicability.ConclusionThe architectural model proposed here lays the groundwork to overcome the obstacles to sharing and reusing experience gained in the software testing and test management. As such, it provides guidance for developing software testing lesson learned systems.     

用例模型与装配式软件系统的开发

用例是获取需求的主要工具，用例模型成了与用户交流的手段。装配式软件是一种能提高软件适应性和生命力的系统，它是建立在基于组件的工程基础之上，以便系统维护时可以按组件装配、拆卸和替换。讨论了用例模型中的用例如何与组件建立映射关系，并给出装配式软件开发的具体过程。     

Use of observers for the inversion of nonlinear maps

In this paper we deal with the problem of the inversion of nonlinear maps. The first contribution of the paper is the definition, in a formal framework, of some problems related to map inversion, which are already present in the literature, for instance in the robotics area and in observer theory. The second and the main contribution consists in the solution of such problems by means of observers, for which some structures are proposed, for the state estimation of a time-varying nonlinear system associated with the given map and reference trajectory.     

Deadlock-freedom in component systems with architectural constraints

We present a compositional analysis of deadlock-freedom in component systems with multiway cooperation. We require the systems to satisfy an architectural constraint which makes sure that the communication structure between the components is given by a tree. Only pairs of components have to be examined for the analysis, therefore the cost is polynomial in the size of the input. We shortly discuss a prototype algorithm which is based on our results and can be used for the investigation of deadlock-freedom of systems satisfying the architectural constraint.     

Software reengineering for complex systems

Reengineering complex software is a difficult task that requires the expenditure of significant resources. To reduce associated costs and improve resultant systems, automated techniques have been developed that can be used throughout all phases of the reengineering process. Three systems are described that have been used successfully for reengineering at The Johns Hopkins University Applied Physics Laboratory. The first system automatically transforms software written in CMS-2 to software written in Ada. The second system supports database design and automated query formulation, and employs conceptual-level intermediate representations for reverse and forward engineering as well as reengineering. The final system utilizes automated techniques to reengineer critical functions for performance enhancement. The systems described are evolving, and will provide a basis for future reengineering efforts.