Whitepaper: The Value of Improving the Separation of Concerns

Microsoft's enterprise customers are demanding better ways to modularize their software systems. They look to the Java community, where these needs are being met with language enhancements, improved developer tools and middleware, and better runtime support. We present a business case for why Microsoft should give priority to supporting better modularization techniques, also known as advanced separation of concerns (ASOC), for the .NET platform, and we provide a roadmap for how to do so

Context-driven progressive enhancement of mobile web applications: a multicriteria decision-making approach

Personal computing has become all about mobile and embedded devices. As a result, the adoption rate of smartphones is rapidly increasing and this trend has set a need for mobile applications to be available at anytime, anywhere and on any device. Despite the obvious advantages of such immersive mobile applications, software developers are increasingly facing the challenges related to device fragmentation. Current application development solutions are insufficiently prepared for handling the enormous variety of software platforms and hardware characteristics covering the mobile eco-system. As a result, maintaining a viable balance between development costs and market coverage has turned out to be a challenging issue when developing mobile applications. This article proposes a context-aware software platform for the development and delivery of self-adaptive mobile applications over the Web. An adaptive application composition approach is introduced, capable of autonomously bypassing context-related fragmentation issues. This goal is achieved by incorporating and validating the concept of fine-grained progressive application enhancements based on a multicriteria decision-making strategy

AO-OpenCom: an AO-Middleware architecture supporting flexible dynamic reconfiguration

Middleware has emerged as a key technology in the construction of distributed systems. As a consequence, middleware is increasingly required to be highly modular and configurable, to support separation of concerns between services, and, crucially, to support dynamic reconfiguration: i.e. to be capable of being changed while running. Aspect-oriented middleware is a promising technology for the realisation of distributed reconfiguration in distributed systems. In this paper we propose an aspect-oriented middleware platform called AO-OpenCom that builds AO-based reconfiguration on top of a dynamic component approach to middleware system composition. The goal is to support extremely flexible dynamic reconfiguration that can be applied at all levels of the system and uniformly across the distributed environment. We evaluate our platform by the capability in meeting flexible reconfiguration and the impact of these overheads

Improving Reuse of Distributed Transaction Software with Transaction-Aware Aspects

Implementing crosscutting concerns for transactions is difficult, even using Aspect-Oriented Programming Languages (AOPLs) such as AspectJ. Many of these challenges arise because the context of a transaction-related crosscutting concern consists of loosely-coupled abstractions like dynamically-generated identifiers, timestamps, and tentative value sets of distributed resources. Current AOPLs do not provide joinpoints and pointcuts for weaving advice into high-level abstractions or contexts, like transaction contexts. Other challenges stem from the essential complexity in the nature of the data, operations on the data, or the volume of data, and accidental complexity comes from the way that the problem is being solved, even using common transaction frameworks. This dissertation describes an extension to AspectJ, called TransJ, with which developers can implement transaction-related crosscutting concerns in cohesive and loosely-coupled aspects. It also presents a preliminary experiment that provides evidence of improvement in reusability without sacrificing the performance of applications requiring essential transactions. This empirical study is conducted using the extended-quality model for transactional application to define measurements on the transaction software systems. This quality model defines three goals: the first relates to code quality (in terms of its reusability); the second to software performance; and the third concerns software development efficiency. Results from this study show that TransJ can improve the reusability while maintaining performance of TransJ applications requiring transaction for all eight areas addressed by the hypotheses: better encapsulation and separation of concern; loose Coupling, higher-cohesion and less tangling; improving obliviousness; preserving the software efficiency; improving extensibility; and hasten the development process

Integrating Authentic Digital Resources in Support of Deep, Meaningful Learning

"Integrating Authentic Digital Resources in Support of Deep, Meaningful Learning," a white paper prepared for the Smithsonian by Interactive Educational Systems Design Inc., describes instructional approaches that apply to successful teaching with the Smithsonian Learning Lab.After defining its use of terms such as deeper learning and authentic resources the authors review the research basis of three broad approaches that support integrating digital resources into the classroom:Project-based learningGuided exploration of concepts and principlesGuided development of academic skillsThese approaches find practical application in the last section of the paper, which includes seven case studies. Examples range from first-grade science, to middle-school English (including ELL strategy) to a high-school American government class. In each example, students study and analyze digital resources, going on to apply their knowledge and deepen their understanding of a range of topics and problems

Aspects enhance the flexibility and modularity of simulation models

While the popularity of simulation models as a tool to address complex problems has increased in recent years, issues of flexibility and modularity associated with simulation models are yet not well explored. These two issues emerge from software engineering challenges arising from implementation and management of model execution, maintenance of metadata corresponding to scenario results, inter-dependency of modelers and end-users to modify model output for exploring patterns of interest, a frequent need to debug and the occasional unavailability of sufficient data to offer effective estimates for model parameters. These challenges have often led simulation modelers to adopt to various mechanisms like manual documentation, tracing, calibration etc., but not to much success due to the other limitations associated with each of these processes. We present here techniques to enhance flexibility, modularity, usefulness and effectiveness of simulation modeling by using Aspect Oriented Programming. The core concepts of Aspect Oriented Programming have been utilized to implement two aspect-based frameworks first, a logging and tracing tool for capturing the high-level execution results and, separately, low-level details associated with model executions, and second, a MCMC tool for estimating model parameters by sampling from their joint posterior distributions using a rigorous statistical approach formed by combining Bayesian Markov Chain Monte Carlo (MCMC) methods with dynamic models. We describe here both the frameworks, including their implementations and functioning, experiments conducted, and results obtained