On the Intrinsic Locality Properties of Web Reference Streams

There has been considerable work done in the study of Web reference streams: sequences of requests for Web objects. In particular, many studies have looked at the locality properties of such streams, because of the impact of locality on the design and performance of caching and prefetching systems. However, a general framework for understanding why reference streams exhibit given locality properties has not yet emerged. In this work we take a first step in this direction, based on viewing the Web as a set of reference streams that are transformed by Web components (clients, servers, and intermediaries). We propose a graph-based framework for describing this collection of streams and components. We identify three basic stream transformations that occur at nodes of the graph: aggregation, disaggregation and filtering, and we show how these transformations can be used to abstract the effects of different Web components on their associated reference streams. This view allows a structured approach to the analysis of why reference streams show given properties at different points in the Web. Applying this approach to the study of locality requires good metrics for locality. These metrics must meet three criteria: 1) they must accurately capture temporal locality; 2) they must be independent of trace artifacts such as trace length; and 3) they must not involve manual procedures or model-based assumptions. We describe two metrics meeting these criteria that each capture a different kind of temporal locality in reference streams. The popularity component of temporal locality is captured by entropy, while the correlation component is captured by interreference coefficient of variation. We argue that these metrics are more natural and more useful than previously proposed metrics for temporal locality. We use this framework to analyze a diverse set of Web reference traces. We find that this framework can shed light on how and why locality properties vary across different locations in the Web topology. For example, we find that filtering and aggregation have opposing effects on the popularity component of the temporal locality, which helps to explain why multilevel caching can be effective in the Web. Furthermore, we find that all transformations tend to diminish the correlation component of temporal locality, which has implications for the utility of different cache replacement policies at different points in the Web.National Science Foundation (ANI-9986397, ANI-0095988); CNPq-Brazi

Forum Session at the First International Conference on Service Oriented Computing (ICSOC03)

The First International Conference on Service Oriented Computing (ICSOC) was held in Trento, December 15-18, 2003. The focus of the conference ---Service Oriented Computing (SOC)--- is the new emerging paradigm for distributed computing and e-business processing that has evolved from object-oriented and component computing to enable building agile networks of collaborating business applications distributed within and across organizational boundaries. Of the 181 papers submitted to the ICSOC conference, 10 were selected for the forum session which took place on December the 16th, 2003. The papers were chosen based on their technical quality, originality, relevance to SOC and for their nature of being best suited for a poster presentation or a demonstration. This technical report contains the 10 papers presented during the forum session at the ICSOC conference. In particular, the last two papers in the report ere submitted as industrial papers

SOLAM: A Novel Approach of Spatial Aggregation in SOLAP Systems

In the context of a data driven approach aimed to detect the real and responsible factors of the transmission of diseases and explaining its emergence or re-emergence, we suggest SOLAM (Spatial on Line Analytical Mining) system, an extension of Spatial On Line Analytical Processing (SOLAP) with Spatial Data Mining (SDM) techniques. Our approach consists of integrating EPISOLAP system, tailored for epidemiological surveillance, with spatial generalization method allowing the predictive evaluation of health risk in the presence of hazards and awareness of the vulnerability of the exposed population. The proposed architecture is a single integrated decision-making platform of knowledge discovery from spatial databases. Spatial generalization methods allow exploring the data at different semantic and spatial scales while reducing the unnecessary dimensions. The principle of the method is selecting and deleting attributes of low importance in data characterization, thus produces zones of homogeneous characteristics that will be merged

The guardians of the welfare state: Universal Credit, welfare control and the moral economy of frontline work in austerity Britain

Ongoing processes of ‘austerity localism’, including the state’s withdrawal from local communities, have created heightened pressures at the frontline. Sitting in local authorities, third sector bodies and community organisations, frontline workers come to act as the de facto guardians of a much-diminished welfare state. Yet, in a situation where needs outweigh resources, they also allocate support based on moral hierarchies of deservingness. This Janus-faced role of frontline workers as both a bulwark against, and an enabler of, neo-liberal welfare control is examined through the framework of a moral economy of frontline work. I argue that the tensions reflect a deeper struggle over competing notions of citizenship, and of the state’s responsibilities towards its citizens, in austerity Britain today

More Than One Lane Wide: Against Hierarchies of Helping in Progressive Legal Advocacy

Progressive legal scholars and practitioners have created a hierarchy within social justice lawyering. Direct service attorneys-nonprofit attorneys who focus on helping individuals in civil cases-sit at the bottom. In the 1960s, progressive theorists advanced a negative portrayal of direct service attorneys as a class. This discourse has continued through different phases in the development of progressive legal theory. Direct service work is done primarily by women in the service of women, has the aesthetic of traditional women\u27s work, and can be understood as embodying the thesis that women have a greater existential and psychological connection to others than men. Like other forms of women\u27s work, direct service work often goes unrecognized even though more visible progressive work depends on it. Negative portrayals of direct service attorneys employ a strategy of oppositional definition that is representative of binary male thinking and deny a positive view of direct service work as life-sustaining service to others. This article discusses the harms perpetuated by hierarchies of helping and sketches a more inclusive vision of progressive lawyering

Visually Characterizing Source Code Changes

International audienceRevision Control Systems (e.g., SVN, Git, Mercurial) include automatic and advanced merging algorithms that help developers to merge their modifications with development repositories. While these systems can help to textually detect conflicts, they do not help to identify the semantic consequences of a change. Unfortunately, there is little support to help release masters (integrators) to take decisions about the integration of changes into the system release. Most of the time, the release master needs to read all the modified code, check the diffs to build an idea of a change, and dig for details from related unchanged code to understand the context and potential impact of some changes. As a result, such a task can be overwhelming. In this article we present a visualization tool to support integrators of object-oriented programs in comprehending changes. Our approach named Torch characterizes changes based on structural informa- tion, authors and symbolic information. It mixes text-based diff information with visual representation and metrics characterizing the changes. The current implementation of our approach analyses Smalltalk programs, and thus we de- scribe our experiments applying it to Pharo, a large open-source system. We also report on the evaluations of our approach by release masters and developers of several open-source projects

Visually Supporting Source Code Changes Integration: the Torch Dashboard

International audienceAutomatic and advanced merging algorithms help programmers to merge their modifications in main development repositories. However, there is little support to help release masters (integrators) to take decisions about the integration of published merged changes into the system release. Most of the time, the release master has to read all the changed code, check the diffs to build an idea of a change, and read unchanged code to understand the context of some changes. Such a task can be overwhelming. In this paper we present a dashboard to support integrators getting an overview of proposed changes in the context of object-oriented programming. Our approach named Torch characterizes changes based on structural information, authors and symbolic information. It mixes text-based diff information with visual representation and metrics characterizing the changes. We describe our experiment applying it to Pharo, a large open-source system, and report on the evaluation of our approach by release masters of several open-source projects

Early aspects: aspect-oriented requirements engineering and architecture design

This paper reports on the third Early Aspects: Aspect-Oriented Requirements Engineering and Architecture Design Workshop, which has been held in Lancaster, UK, on March 21, 2004. The workshop included a presentation session and working sessions in which the particular topics on early aspects were discussed. The primary goal of the workshop was to focus on challenges to defining methodical software development processes for aspects from early on in the software life cycle and explore the potential of proposed methods and techniques to scale up to industrial applications

Understanding the Use of Inheritance with Visual Patterns

International audienceThe goal of this work is to visualize inheritance in object-oriented programs to help its comprehension. We propose a single, compact view of all class hierarchies at once using a custom Sunburst layout. It enables to quickly discover interesting facts across classes while preserving the essential relationship between parent and children classes. We explain how standard inheritance metrics are mapped into our visualization. Additionally, we define a new metric characterizing similar children classes. Using these metrics and the proposed layout, a set of common visual patterns is derived. These patterns allow the programmer to quickly understand how inheritance is used and provide answers to some essential questions when performing program comprehension tasks. Our approach is evaluated through a case study that involves examples from large programs, demonstrating its scalability