An Empirical Study of the Effectiveness of 'Forcing Diversity' Based on a Large Population of Diverse Programs

Use of diverse software components is a viable defence against common-mode failures in redundant softwarebased systems. Various forms of "Diversity-Seeking Decisions" (“DSDs”) can be applied to the process of developing, or procuring, redundant components, to improve the chances of the resulting components not failing on the same demands. An open question is how effective these decisions, and their combinations, are for achieving large enough reliability gains. Using a large population of software programs, we studied experimentally the effectiveness of specific "DSDs" (and their combinations) mandating differences between redundant components. Some of these combinations produced much better improvements in system probability of failure per demand (PFD) than "uncontrolled" diversity did. Yet, our findings suggest that the gains from such "DSDs" vary significantly between them and between the application problems studied. The relationship between DSDs and system PFD is complex and does not allow for simple universal rules (e.g. "the more diversity the better") to apply

Choosing effective methods for design diversity - How to progress from intuition to science

Design diversity is a popular defence against design faults in safety critical systems. Design diversity is at times pursued by simply isolating the development teams of the different versions, but it is presumably better to "force" diversity, by appropriate prescriptions to the teams. There are many ways of forcing diversity. Yet, managers who have to choose a cost-effective combination of these have little guidance except their own intuition. We argue the need for more scientifically based recommendations, and outline the problems with producing them. We focus on what we think is the standard basis for most recommendations: the belief that, in order to produce failure diversity among versions, project decisions should aim at causing "diversity" among the faults in the versions. We attempt to clarify what these beliefs mean, in which cases they may be justified and how they can be checked or disproved experimentally

The Partial Evaluation Approach to Information Personalization

Information personalization refers to the automatic adjustment of information content, structure, and presentation tailored to an individual user. By reducing information overload and customizing information access, personalization systems have emerged as an important segment of the Internet economy. This paper presents a systematic modeling methodology - PIPE (`Personalization is Partial Evaluation') - for personalization. Personalization systems are designed and implemented in PIPE by modeling an information-seeking interaction in a programmatic representation. The representation supports the description of information-seeking activities as partial information and their subsequent realization by partial evaluation, a technique for specializing programs. We describe the modeling methodology at a conceptual level and outline representational choices. We present two application case studies that use PIPE for personalizing web sites and describe how PIPE suggests a novel evaluation criterion for information system designs. Finally, we mention several fundamental implications of adopting the PIPE model for personalization and when it is (and is not) applicable.Comment: Comprehensive overview of the PIPE model for personalizatio

How Would You Like Your Television: With or Without Borders and With or Without Culture--a New Approach to Media Regulation in the European Union

This Essay analyzes the effectiveness of television broadcasting regulations as a means to effectuate the promotion and protection of a pan-European culture, namely, television broadcasting regulations. First, in Part I, this Essay considers the broader background developments in the audio-visual sector that led to the passing of the Directive. Part II looks at the advantages and disadvantages of the most controversial aspect of the Directive, namely, the quota provisions. Part III critiques the Directive\u27s effectiveness in realizing its dual goals of both protecting and promoting a pan-European culture. Finally, Part IV compares the goals enunciated in the Federal Communications Act ( FCC Act ) with those enunciated in the Directive. Both sets of goals reflect similar concerns and interests, although the United States takes a much broader approach in realizing its goals. This Essay concludes that the Community should, like the United States, take a more expansive approach to its audio-visual policy, similar to the approach reflected in the FCC Act, in order to strengthen and effectuate a more solid and unified European broadcast regulatory scheme that both protects and promotes a European culture

A Browser-based IDE for the MUzECS Platform

We report on a scalable, portable, and secure visual development environment for programming embedded Arduino platforms with Chromebooks in a successful secondary school computer science curriculum. Our web-based environment is part of the larger MUzECS project, an inexpensive replacement module for the Exploring Computer Science (ECS) course being widely deployed in United States high schools. Students use MUzECS to gain a deeper understanding of computing, through a set of blocks which provide appropriate abstractions for working with low-level hardware. MUzECS improves upon the existing curriculum module by reducing the hardware cost by an order of magnitude, while still preserving the key ECS pillars of computer science content, student inquiry and classroom equity. Programming with visual blocks provides a more attractive tool for introductory courses than traditional approaches, and yet enables high-impact exploration activities such as building a series of embedded musical instruments. The current work combines and modifies several existing tools to eliminate technical barriers on low-cost platforms like Chromebooks, such as the reliance on special block-based toolchains, remote compilation servers, or multi-stage transfers for student code

Arts for All: Connecting to New Audiences

Summarizes discussions among arts leaders and experts at an April 2008 conference on how to build arts appreciation and participation in a new environment through better marketing, new technology, and audience research

The Application of EC Competition Policy to the Media Industry

This article examines whether EC competition policy and merger control provisions can prevent excessive market power and safeguard open access and consumer choice in the European media and communications industry. The study looks at the structure of the media industry and points to the amalgamation of corporate power. It assesses whether EC competition law and merger provisions can effectively address the dangers of ownership concentration and safeguard diversity of sources. A number of merger cases either blocked or allowed by the EC are reviewed in order to establish the level of competition. The article suggests that a more rigorous competition policy is required to guarantee competition and prevent domination in merger activity

Digital Ecosystems: Ecosystem-Oriented Architectures

We view Digital Ecosystems to be the digital counterparts of biological ecosystems. Here, we are concerned with the creation of these Digital Ecosystems, exploiting the self-organising properties of biological ecosystems to evolve high-level software applications. Therefore, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems, where the optimisation works at two levels: a first optimisation, migration of agents which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. The Digital Ecosystem was then measured experimentally through simulations, with measures originating from theoretical ecology, evaluating its likeness to biological ecosystems. This included its responsiveness to requests for applications from the user base, as a measure of the ecological succession (ecosystem maturity). Overall, we have advanced the understanding of Digital Ecosystems, creating Ecosystem-Oriented Architectures where the word ecosystem is more than just a metaphor.Comment: 39 pages, 26 figures, journa

The Immune System: the ultimate fractionated cyber-physical system

In this little vision paper we analyze the human immune system from a computer science point of view with the aim of understanding the architecture and features that allow robust, effective behavior to emerge from local sensing and actions. We then recall the notion of fractionated cyber-physical systems, and compare and contrast this to the immune system. We conclude with some challenges.Comment: In Proceedings Festschrift for Dave Schmidt, arXiv:1309.455