The development of secure software could be simplified if tooling were readily available to application developers. Improvements can be made to better support software developers to secure their applications, without requiring that security code be inserted throughout core application processing code. The Aclamate framework is introduced here for securing software that imposes little restrictions on the writing of software. Aclamate uses AOSD to secure applications in a non-invasive manner. Both the existing state of software security frameworks and what support already exists to assist application development are discussed. Emphasis is placed on access control and authorization - as these areas are particularly lacking with security tooling to support software development in a non-invasive manner. Finally, there is a critique of Aclamate, the challenges remain in its development, and the remaining opportunities that may exist to provide application developers with more tools to ease the development of secure software

Experiences with Auto-adaptive and Reconfigurable Systems (Application Level Adaptation)This is the second part of the special issue on auto-adaptive and reconfigurable systems.The first part of this special issue was dedicated to experience at the system level while this part will focus on the application level.Emerging new technologies enable applications that require autoadaptive software.The new characteristics of these emerging technologies demand innovative approaches.Since the configurations needed in a particular context can hardly be anticipated, the software must support dynamic non-invasive approaches to behavioral adaptation in specific applications.Different applications exhibit different requirements regarding adaptivity and reconfigurability.The development of these applications requires new approaches to designing each specific application architecture in order to enable the application at hand to exhibit dynamic adaptability.In addition, linguistic expressions that can enable the implementation of dynamic adaptability are needed.The papers in this volume present both abstractions and techniques for designing general purpose adaptive and reconfigurable applications and also domain-specific abstractions and techniques for specific applications.'ISAMadapt: abstractions and tools for designing general-purpose pervasive applications', by I. Augustin et al., introduces the ISAMadapt project, which approaches the challenge of supporting 'follow-me' semantics for building generic applications that run in the pervasive environment.The programming abstractions used for building pervasive applications are based on four concepts: context, adapter, adaptation command and policy.Collaborative integration of the application with the middleware that manages the whole pervasive environment is necessary.The ISAM architecture combines the management of pervasive applications at runtime and the design/coding of an application's context aware behaviors into a comprehensive computational model.The paper proposes programming tools to express mobility and context-aware adaptability in a natural way that simplifies the implementation.Practical application of the suggested technology and integration with current technologies are reported as future plans in order to better evaluate the proposal.In 'The FRACTAL component model and its support in Java', by Eric Bruneton et al., a reflective component model is presented to support application level adaptation.The FRACTAL framework allows programmers to enhance components with a user-defined extensible set of reflective capabilities.This feature allows fine-grained manipulation of components' internal structures.JULIA is a Java implementation of the model that provides a small runtime library together with byte code generation using aspect weaving to allow the creation and combination of controller and interceptor classes.FRACTAL and JULIA are currently being used for evaluation and extensions.Some future applications planned by the authors are the development of a dynamic Architecture Description Language (ADL)

Abstract Concurrent systems tend to have certain properties that are not localized in single modular units, but their implementations cut across functional components, increasing coupling and making modular units difficult to reuse and adapt. Example properties include concurrency, synchronization, and authentication. This problem is particularly apparent in systems with evolving requirements, as adapting code that is not localized in single modular units proves to be a tedious process. In this paper we discuss issues related to requirements of concurrent software systems to provide explicit support for these cross‐cutting concerns, and we present the Aspect Moderator, a framework extension to the object model that can ease the development of concurrent object‐oriented systems. Copyright © 2002 John Wiley & Sons, Ltd.

We present a reflective decision control mechanism for dealing with synchronization and scheduling issues in a distributed computing environment. We present a component-based reflective architecture for assisting distributed objects in decision making. It enables autonomous entities to support reflective computation that requires a flexible means for managing the course of computation, resource allocation and scheduling. Such capability is critical to the successful implementation of distributed software that supports real-time and reactive/adaptive applications (e.g., robotics, manufacturing, and military systems). In many instances, these systems must be designed to monitor and manage complex systems in dynamic settings.

In wireless ATM networks, user connections need to be rerouted during handoff as mobile users move among base stations. The rerouting of connections must be done quickly with minimal disruption to traffic. In addition, the resulting routes must be optimal. A reasonable approach is to implement handoff in two phases. In the first phase connections are rapidly rerouted and in the second phase a periodic route optimization procedure is executed. The route optimization should impose minimal signaling and processing load on the ATM switches. In this paper, we propose and study a periodic execution of route optimization for a two-phase handoff scheme. We study two types of execution: non-adaptive and adaptive. For the adaptive optimization, we consider two adaptation schemes that are dependent on network conditions. A simulation model is developed to study system performance. The adaptive route optimization is shown to minimize signaling and processing load while maximizing utilization of reserved resources.

No abstract available.

To be effective in addressing specific requirements found in the intended computing domains of a given object-oriented language, several researchers have tended to introduce new notation into current existing interface constructs. Current research that provides such interfaces can be classified into two categories: one embedding special purpose interface construct in language syntax and can not be adapted further by end-users; the other provides an open way that programmers can tailor new interface construct to their need. In either way, programmers suffer the inheritance anomaly and the inheritance exclusion. To handle such disadvantages, this paper presents our language adapter++, in which programmers can adapt the object model to different computing environments, and then reify the internal object state into a separated virtual interface, called virtual adapter. The virtual adapter along with traditional interface can be used to define an object as if using the integrated construct.

In this paper we present a concurrent object-oriented model in which a concurrent object, which represents a shared resource abstraction in our model, is decomposed into a hierarchy of architectural abstractions: a shared data abstraction, a synchronization abstraction, and a scheduling abstraction. It will be shown that the separation of concerns among the three major components of the concurrent objects avoids many of the conceptual difficulties that arise when integrating concurrency into the object-oriented paradigm. The proposed model presents a formal methodology for the architectural design and specification of the concurrent object-oriented software systems. The notion of scheduling policy inheritance in our model facilitates the process of engineering adaptability in the development of the intelligent reactive/adaptive systems.

The authors propose to view cooperating tasks in distributed systems as both CSPs: (communicating sequential processes) and SCLs (sequential cooperating layers). This dual, complementary, view of distributed systems is based on the notion of communication closed layers. The same state-space abstraction and global assertions that were used for the design, development, verification, and testing of such systems are used as the guide and support for scheduling. With a given partition and a given mapping the scheduling guarantees the best performance. It takes advantage of the syntactic visibility of the logic behind task cooperation.>

Courses in concurrent programming are now a standard part of computer science curricula.The control of task scheduling and intertask communication scheduling within concurrent programs are important aspects in understanding the tasking model especially for embedded real-time systems.In order to deal with these scheduling controls in a systematic way in the classroom, the Illinois Institute of Technology has developed terminology to classify these controls.This paper describes this classification, gives examples of each control in current concurrent languages, and discusses the issues related to each control.