Software dependability modeling using an industry-standard architecture description language

Performing dependability evaluation along with other analyses at architectural level allows both making architectural tradeoffs and predicting the effects of architectural decisions on the dependability of an application. This paper gives guidelines for building architectural dependability models for software systems using the AADL (Architecture Analysis and Design Language). It presents reusable modeling patterns for fault-tolerant applications and shows how the presented patterns can be used in the context of a subsystem of a real-life application

Investigating web APIs on the World Wide Web

Abstract—The world of services on the Web, thus far limited to “classical ” Web services based on WSDL and SOAP, has been increasingly marked by the domination of Web APIs, characterised by their relative simplicity and their natural suitability for the Web. Currently, the development of Web APIs is rather autonomous, guided by no established standards or rules, and Web API documentation is commonly not based on an interface description language such as WSDL, but is rather given directly in HTML as part of a webpage. As a result, the use of Web APIs requires extensive manual effort and the wealth of existing work on supporting common service tasks, including discovery, composition and invocation, can hardly be reused or adapted to APIs. Before we can achieve a higher level of automation and can make any significant improvement to current practices and technologies, we need to reach a deeper understanding of these. Therefore, in this paper we present a thorough analysis of the current landscape of Web API forms and descriptions, which has up-to-date remained unexplored. We base our findings on manually examining a body of publicly available APIs and, as a result, provide conclusions about common description forms, output types, usage of API parameters, invocation support, level of reusability, API granularity and authentication details. The collected data provides a solid basis for identifying deficiencies and realising how we can overcome existing limitations. More importantly, our analysis can be used as a basis for devising common standards and guidelines for Web API development. Keywords-Web APIs, RESTful services, Web services I

The C Object System: Using C as a High-Level Object-Oriented Language

The C Object System (Cos) is a small C library which implements high-level concepts available in Clos, Objc and other object-oriented programming languages: uniform object model (class, meta-class and property-metaclass), generic functions, multi-methods, delegation, properties, exceptions, contracts and closures. Cos relies on the programmable capabilities of the C programming language to extend its syntax and to implement the aforementioned concepts as first-class objects. Cos aims at satisfying several general principles like simplicity, extensibility, reusability, efficiency and portability which are rarely met in a single programming language. Its design is tuned to provide efficient and portable implementation of message multi-dispatch and message multi-forwarding which are the heart of code extensibility and reusability. With COS features in hand, software should become as flexible and extensible as with scripting languages and as efficient and portable as expected with C programming. Likewise, Cos concepts should significantly simplify adaptive and aspect-oriented programming as well as distributed and service-oriented computingComment: 18

Repurposing learning objects: a sustainable alternative?

Recent experience shows that reusable learning objects, like the computer assisted learning programmes of the early 1990s, have so far failed to achieve expected levels of integration into educational practice. This is despite technical interoperability, cataloguing systems, high quality standards, targeted dissemination and professional development initiatives. Analysis of this problem suggests that conceptualization of the problem may be limiting the scope of solutions. This paper proposes a sustainable and participative approach to reuse that involves repurposing learning objects for different discipline areas. For some time now there has been a growing awareness that even the most accessible resources have failed to be widely adopted by the educational community and as a result have also failed to fulfil their considerable educational potential. (Campbell, 2003, p. 35

An architecture-based dependability modeling framework using AADL

For efficiency reasons, the software system designers' will is to use an integrated set of methods and tools to describe specifications and designs, and also to perform analyses such as dependability, schedulability and performance. AADL (Architecture Analysis and Design Language) has proved to be efficient for software architecture modeling. In addition, AADL was designed to accommodate several types of analyses. This paper presents an iterative dependency-driven approach for dependability modeling using AADL. It is illustrated on a small example. This approach is part of a complete framework that allows the generation of dependability analysis and evaluation models from AADL models to support the analysis of software and system architectures, in critical application domains

Co-authorship in the age of cyberculture: Open Educational Resources at the Open University of the United Kingdom

Locating Open Educational Resources (OER) as a phenomenon of cyberculture, this paper presents a reflection on the possibilities of co-authorship that are entailed in OER initiatives of different natures and settings within a large organisation. A selection of OER-related projects and activities carried out at the Open University of United Kingdom (UKOU) are examined from the perspective of a comparative framework proposed by Okada (2010). The framework identifies key features and differences between ‘Closed’ and ‘Open’ Education, that is, respectively, formal education, which takes place within the constraints of institutional Virtual Learning Environments, and informal education, which is gradually taking place more widely in cyberspace. The paper is introduced with a succinct discussion of the connection between cyberculture and the emergence of OER, followed by a presentation of the comparative framework adopted. The UKOU´s structure and methods are then presented, and various projects are discussed. The article concludes by proposing a brief commentary on the creative potential that is being unleashed at the very boundaries between formal and informal educational spaces that cyberculture is challenging

The future of technology enhanced active learning – a roadmap

The notion of active learning refers to the active involvement of learner in the learning process, capturing ideas of learning-by-doing and the fact that active participation and knowledge construction leads to deeper and more sustained learning. Interactivity, in particular learnercontent interaction, is a central aspect of technology-enhanced active learning. In this roadmap, the pedagogical background is discussed, the essential dimensions of technology-enhanced active learning systems are outlined and the factors that are expected to influence these systems currently and in the future are identified. A central aim is to address this promising field from a best practices perspective, clarifying central issues and formulating an agenda for future developments in the form of a roadmap

A software development environment utilizing PAMELA

Hardware capability and efficiency has increased dramatically since the invention of the computer, while software programmer productivity and efficiency has remained at a relatively low level. A user-friendly, adaptable, integrated software development environment is needed to alleviate this problem. The environment should be designed around the Ada language and a design methodology which takes advantage of the features of the Ada language as the Process Abstraction Method for Embedded Large Applications (PAMELA)