Martlesham Heath, United Kingdom
Martlesham Heath, United Kingdom

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Popkin T.,Queen Mary, University of London | Cavallaro A.,Queen Mary, University of London | Hands D.,BT Innovate and Design
IEEE Transactions on Image Processing | Year: 2010

This paper presents a computationally efficient algorithm for smoothly space-variant Gaussian blurring of images. The proposed algorithm uses a specialized filter bank with optimal filters computed through principal component analysis. This filter bank approximates perfect space-variant Gaussian blurring to arbitrarily high accuracy and at greatly reduced computational cost compared to the brute force approach of employing a separate low-pass filter at each image location. This is particularly important for spatially variant image processing such as foveated coding. Experimental results show that the proposed algorithm provides typically 10 to 15 dB better approximation of perfect Gaussian blurring than the blended Gaussian Pyramid blurring approach when using a bank of just eight filters. © 2010 IEEE.


Schmidt F.,ISC Gebhardt | Spott M.,BT Innovate and Design
Advances in Intelligent Systems and Computing | Year: 2013

In the past years pattern detection has gained in importance for many companies. As the volume of collected data increases so does typically the number of found patterns. To cope with this problem different interestingness measures for patterns have been proposed. Unfortunately, their usefulness turns out to be limited in practical applications. To address this problem, we propose a novel visualisation technique that allows analysts to explore patterns interactively rather than presenting analysts with static ordered lists of patterns. Specifically, we focus on an interactive visualisation of temporal frequent item sets with hierarchical attributes. © 2013 Springer-Verlag.


De Leusse P.,AGH University of Science and Technology | Dimitrakos T.,BT Innovate and Design
Proceedings - 4th International Conference on Emerging Security Information, Systems and Technologies, SECURWARE 2010 | Year: 2010

Business requirements for rapid operational efficiency, customer responsiveness as well as rapid adaptability are actively driving the need for ever increasing communication and integration capabilities of software assets. In this context, security, although acknowledged as being a necessity, is often perceived as a hindrance. Indeed, dynamic environments require flexible and understandable security that can be customized, adapted and reconfigured dynamically to face changing requirements. In this paper, the authors propose SOA-based security governance middleware that handles security requirements on behalf of a resource exposed through it. The middleware aims at providing different security settings through the use of managed compositions of security services called profiles. The main added value of this work compared to existing handlers or centralized approaches lies in its enhanced flexibility and transparency. © 2010 IEEE.


Launders I.,BT Innovate and Design
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

The Transaction Graph is argued as leading to a better understanding of the concepts and relations in enterprise transactions and their semantics with business rules. This design process begins with an analysis of case study narrative through the Transactional Use-Case, using a Financial Trading case study in this evaluation. The lexicon or dictionary of words and their underlying concepts are explored in order to model transactions. Peirce logic (i.e. Peirce's visual Extential Graphs as extended by Sowa and Heaton) is then applied to the business rules to visualise the inferences in Conceptual Graphs and therefore any further possible Transaction Graph refinements. Model automation provides validation checking removing errors in semantics and syntactics. The paper demonstrates the reuse and refinement of a generic Transaction Model highlighting inference and logical operations with business rules. Additionally the paper demonstrates the reuse of the automated Transaction Model's ontology coupled with its conceptual catalogue. © 2011 Springer-Verlag.


Tandur D.,Agilent Technologies | Duplicy J.,Agilent Technologies | Arshad K.,University of Greenwich | Depierre D.,Thales Alenia | And 5 more authors.
IEEE Vehicular Technology Magazine | Year: 2012

A vertically integrated approach is presented to evaluate the performance of cognitive radio (CR) systems. The approach consists of three pillars: measurement, modeling, and emulation (MME). This integrated approach enables the reproduction of the radio environment in laboratory conditions and aims to guarantee the same performance results as one would obtain in the field. This article provides a detailed explanation for each pillar along with state-of-the-art overviews. Finally, a test bed based on the MME approach is presented. © 2012 IEEE.


Shakya S.,BT Innovate and Design | Santana R.,Technical University of Madrid
Adaptation, Learning, and Optimization | Year: 2012

In this chapter we describe Markovian Optimisation Algorithm (MOA), one of the recent developments in MN based EDA. It uses the local Markov property to model the dependency and directly sample from it without needing to approximate a complex join probability distribution model. MOA has a much simpler workflow in comparison to its global property based counter parts, since expensive processes to finding cliques, and building and estimating clique potential functions are avoided. The chapter is intended as an introductory chapter, and describes the motivation and the workflow of MOA. It also reviews some of the results obtained with it. © Springer-Verlag Berlin Heidelberg 2012.


Santana R.,University of the Basque Country | Shakya S.,BT Innovate and Design
Adaptation, Learning, and Optimization | Year: 2012

This chapter introduces probabilistic graphical models and explain their use for modelling probabilistic relationships between variables in the context of optimisation with EDAs.We focus on Markov networksmodels and review different algorithms used to learn and sample Markov networks. Other probabilistic graphical models are also reviewed and their differences with Markov networks are analysed. © Springer-Verlag Berlin Heidelberg 2012.


Nair S.K.,BT Innovate and Design | Porwal S.,University College London | Dimitrakos T.,BT Innovate and Design | Ferrer A.J.,Atos Origin | And 5 more authors.
Proceedings - 8th IEEE European Conference on Web Services, ECOWS 2010 | Year: 2010

The cloud based delivery model for IT resources is revolutionizing the IT industry. Despite the marketing hype around "the cloud", the paradigm itself is in a critical transition state from the laboratories to mass market. Many technical and business aspects of cloud computing need to mature before it is widely adopted for corporate use. For example, the inability to seamlessly burst between internal cloud and external cloud platforms, termed cloud bursting, is a significant shortcoming of current cloud solutions. Furthermore, the absence of a capability that would allow to broker between multiple cloud providers or to aggregate them into a composite service inhibits the free and open competition that would help the market mature. This paper describes the concepts of cloud bursting and cloud brokerage and discusses the open management and security issues associated with the two models. It also presents a possible architectural framework capable of powering the brokerage based cloud services that is currently being developed in the scope of OPTIMIS, an EU FP7 project. © 2010 IEEE.


Shakya S.,BT Innovate and Design | McCall J.,Robert Gordon University | Brownlee A.,Loughborough University | Owusu G.,BT Innovate and Design
Adaptation, Learning, and Optimization | Year: 2012

DEUM is one of the early EDAs to use Markov Networks as its model of probability distribution. It uses undirected graph to represent variable interaction in the solution, and builds a model of fitness function from it. The model is then fitted to the set of solutions to estimate the Markov network parameters; these are then sampled to generate new solutions. Over the years, many differentDEUMalgorithms have been proposed. They range from univariate version that does not assume any interaction between variables, to fully multivariate version that can automatically find structure and build fitness models. This chapter serves as an introductory text on DEUM algorithm. It describes the motivation and the key concepts behind these algorithms. It also provides workflow of some of the key DEUM algorithms. © Springer-Verlag Berlin Heidelberg 2012.


Popkin T.,Queen Mary, University of London | Cavallaro A.,Queen Mary, University of London | Hands D.,BT Innovate and Design
IEEE Transactions on Image Processing | Year: 2011

We introduce the concept of depth-based blurring to achieve an aesthetically acceptable distortion when reducing the bitrate in image coding. The proposed depth-based blurring is a prefiltering that reduces high-frequency components by mimicking the limited depth of field effect that occurs in cameras. To cope with the challenge of avoiding intensity leakage at the boundaries of objects when blurring at different depth levels, we introduce a selective blurring algorithm that simulates occlusion effects as occur in natural blurring. The proposed algorithm can handle any number of blurring and occlusion levels. Subjective experiments show that the proposed algorithm outperforms foveation filtering, which is the dominant approach for bitrate reduction by space-variant prefiltering. © 2011 IEEE.

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