Phil Greenwood

On the impact of aspectual decompositions on design stability: an empirical study

Although one of the main promises of aspect-oriented (AO) programming techniques is to promote better software changeability than objectoriented (OO) techniques, there is no empirical evidence on their efficacy to prolong design stability in realistic development scenarios. For instance, no investigation has been performed on the effectiveness of AO decompositions to sustain overall system modularity and minimize manifestation of ripple-effects in the presence of heterogeneous changes. This paper reports a quantitative case study that evolves a real-life application to assess various facets of design stability of OO and AO implementations. Our evaluation focused upon a number of system changes that are typically performed during software maintenance tasks. They ranged from successive re-factorings to more broadly-scoped software increments relative to both crosscutting and non-crosscutting concerns. The study included an analysis of the application in terms of modularity, change propagation, concern interaction, identification of ripple-effects and adherence to well-known design principles.

Supporting Law Enforcement in Digital Communities through Natural Language Analysis

Recent years have seen an explosion in the number and scale of digital communities (e.g. peer-to-peer file sharing systems, chat applications and social networking sites). Unfortunately, digital communities are host to significant criminal activity including copyright infringement, identity theft and child sexual abuse. Combating this growing level of crime is problematic due to the ever increasing scale of todays digital communities. This paper presents an approach to provide automated support for the detection of child sexual abuse related activities in digital communities. Specifically, we analyze the characteristics of child sexual abuse media distribution in P2P file sharing networks and carry out an exploratory study to show that corpus-based natural language analysis may be used to automate the detection of this activity. We then give an overview of how this approach can be extended to police chat and social networking communities.

A Comparative Study of Aspect-Oriented Requirements Engineering Approaches

Aspect-Oriented Requirements Engineering (AORE) aims at improving separation of concerns in the problem space by offering new ways of modularising requirements. Over recent years several AORE approaches have emerged by evolving contemporary requirements approaches such as viewpoints-, scenarios- and goal-based models. Due to the novelty of these techniques, there is a lack of systematic comparative studies analyzing the benefits and drawbacks they can offer to the requirements engineering practice. This paper presents a case study contrasting four eminent AORE approaches in terms of time effectiveness and accuracy of their produced outcome. We address challenges related to the heterogeneous definitions for AORE model concepts as well as the fact that they perform similar general requirements process activities in different ways. In order to address these challenges, we provide a mapping of the AORE approaches onto general RE activities and provide a common naming scheme. The case study results show that specification of aspect compositions in AORE presents an effort bottleneck that has to be carefully weighed against the added benefits of modularity and analysis of systemic properties offered by AORE. Consequently, our study provides an initial yet significant stepping stone towards improving the evaluation of AORE approaches and understanding their contribution to requirements engineering.

Semantic vs. syntactic compositions in aspect-oriented requirements engineering: an empirical study

Most current aspect composition mechanisms rely on syntactic references to the base modules or wildcard mechanisms quantifying over such syntactic references in pointcut expressions. This leads to the well-known problem of pointcut fragility. Semantics-based composition mechanisms aim to alleviate such fragility by focusing on the meaning and intention of the composition hence avoiding strong syntactic dependencies on the base modules. However, to date, there are no empirical studies validating whether semantics based composition mechanisms are indeed more expressive and less fragile compared to their syntax-based counterparts. In this paper we present a first study comparing semantics- and syntax-based composition mechanisms in aspect-oriented requirements engineering (AORE). In our empirical study the semantics-based compositions examined were found to be indeed more expressive and less fragile. The semantics-based compositions in the study also required one to reason about composition interdependencies early on hence potentially reducing the overhead of revisions arising from later trade-off analysis and stakeholder negotiations. However, this added to the overhead of specifying the compositions themselves. Furthermore, since the semantics-based compositions considered in the study were based on natural language analysis, they required initial effort investment into lexicon building as well as strongly depended on advanced tool support to expose the natural language semantics.

A framework for policy driven auto-adaptive systems using dynamic framed aspects

This paper describes and evaluates a framework that allows adaptive behaviour to be applied to systems by using a combination of dynamic Aspect-Oriented Programming (AOP), parameterisation and policies. Our approach allows the operator to create policies to define adaptive behaviour based on Event-Condition-Action rules. The combination of dynamic AOP with parameterisation aids reuse and allows aspects to be generated to suit the current system conditions; these aspects can then be woven at run time to adapt the application behaviour. This approach is evaluated in two ways; firstly performance measurements are presented to show that such behaviour does not add a substantial overhead to the target system. Secondly, Aspect-Oriented software metrics are applied to the adaptations applied to illustrate their reusability and flexibility.

Who Am I? Analyzing Digital Personas in Cybercrime Investigations

The Isis toolkit offers the sophisticated capabilities required to analyze digital personas and provide investigators with clues to the identity of the individual or group hiding behind one or more personas.

On the Impact of Evolving Requirements-Architecture Dependencies: An Exploratory Study

Architecture design plays a significant role in the evolution of software systems, as it provides the prime realization of the driving requirements and their inter-dependencies. With the increasing volatility of software requirements nowadays, it is necessary to understand the correlation between evolving classical requirements dependencies and their impact on the architectural decomposition. In the context of this analysis, two questions arise: (i) what are the conventional categories of requirements dependencies that are more architecturally significant in terms of change impact? and (ii) to what extent those evolving dependencies tend to generate ripple effects through architectural modules and interfaces. In order to address these two questions, this paper first presents an analysis model that categorizes requirements dependencies. Second, we have performed an exploratory study, based on the change history analysis of a real-life Web-based information system, in order to gather the most architecturally-significant requirements dependencies from our model. We have systematically analyzed ten system releases, based on some qualitative and quantitative indicators, with respect to how the requirements- architecture dependencies and compositions evolved.

Social Networking Privacy: Understanding the Disconnect from Policy to Controls

A proposed method for mapping privacy policy statements to privacy controls can help providers improve data management transparency, thereby increasing user trust.

EA-Analyzer: automating conflict detection in a large set of textual aspect-oriented requirements

One of the aims of Aspect-Oriented Requirements Engineering is to address the composability and subsequent analysis of crosscutting and non-crosscutting concerns during requirements engineering. A composition definition explicitly represents interdependencies and interactions between concerns. Subsequent analysis of such compositions helps to reveal conflicting dependencies that need to be resolved in requirements. However, detecting conflicts in a large set of textual aspect-oriented requirements is a difficult task as a large number of explicitly defined interdependencies need to be analyzed. This paper presents EA-Analyzer, the first automated tool for identifying conflicts in aspect-oriented requirements specified in natural-language text. The tool is based on a novel application of a Bayesian learning method. We present an empirical evaluation of the tool with three industrial-strength requirements documents from different domains and a fourth academic case study used as a de facto benchmark in several areas of the aspect-oriented community. This evaluation shows that the tool achieves up to 93.90 % accuracy regardless of the documents chosen as the training and validation sets.

A Method for Analysing Traceability between Privacy Policies and Privacy Controls of Online Social Networks

Privacy management in online social networks OSNs is a major concern. However, the complexity of privacy policies and the plethora of privacy controls make it very difficult to assess whether the controls adequately implement the intended policies. This paper proposes a method to assess the degree of traceability between privacy policies and privacy controls in OSNs. The resulting analysis enables one to pinpoint key privacy management gaps that must be plugged. The method can be utilised by privacy watchdogs, user rights groups as well as OSNs themselves to assess the effectiveness of privacy measures.