The Department of Computer Science at Leicester.
The department's research is directed to the foundations of computational models, processes and structures, and the way they support the engineering of software intensive systems. Specific areas of interest are:
- Algebraic and Categorical Structures and Methods
- Algorithm Design, Analysis and Engineering
- Computational Complexity of Algebraic Structures
- Deduction, Rewriting and Transformation
- Interaction Design and Evaluation of Socio-technical Systems
- Models of Software Intensive Systems
- Software Evolution
- Verification and Validation
More details are available from the Department's research webpages.
When downloading papers please observe the normal copyright codes and conventions for their use.
Data collection is one of the predominant operations in wireless sensor networks. This paper focuses on the problem of efficient data collection in a setting where some nodes may not possess data each time data is collected. In that case, idle listening slots may occur, which lead to a waste of energy and an increase in latency. To alleviate these problems, successive-slot schedules were proposed by Zhao and Tang (Infocom 2011). In this paper, we introduce a so-called extra-bit technique to r...
Rasul, Aram; Erlebach, Thomas
This paper reports on reusable mobile digital learning resources designed to assist human geography undergraduate students in exploring the geographies of life in Dublin. Developing active learning that goes beyond data collection to encourage observation and thinking in the field is important. Achieving this in the context of large class sizes presents several challenges. Combining in-situ learning with spatially-accurate historical and contemporary multimedia, we developed a set of location...
Jarvis, Claire; Tate, Nicholas; Dickie, Jennifer; Brown, Gavin
We analyze the network congestion game with atomic players, asymmetric strategies, and the maximum latency among all players as social cost. This important social cost function is much less understood than the average latency. We show that the price of anarchy is at most two, when the network is a ring and the link latencies are linear. Our bound is tight. This is the first sharp bound for the maximum latency objective.
Chen, Xujin; Doerr, Benjamin; Doerr, Carola; Hu, Xiaodong; Ma, Weidong... et al.
In this column, I will discuss some recent papers in online algorithms. It is pleasing to see there were a number of papers about online algorithms in the top conferences this year. If I have missed your paper and you want to write about it or about any other topic in online algorithms, don't hesitate to contact me!
van Stee, Rob
Online Bin Stretching is a semi-online variant of bin packing in which the algorithm has to use the same number of bins as the optimal packing, but is allowed to slightly overpack the bins. The goal is to minimize the amount of overpacking, i.e., the maximum size packed into any bin. We give an algorithm for Online Bin Stretching with a stretching factor of 1:5 for any number of bins. We also show a specialized algorithm for three bins with a stretching factor of 11=8 = 1:375.
Böhm, Martin; Sgall, Jin; Stee, Rob van; Veselý, Pavel
Green computing has emerged as a hot topic leading to a need to understand energy consumption of computations. This need also extends to devices with limited resources as are common in the internet of things. RESTful services have shown their potential on such devices, but there are many choices of frameworks for their development and execution. Current research has analysed performance of the frameworks but no attention has been given to systematically studying their power consumption. In th...
Nunes, L. H.; Nakamura, L. H. V.; De F. Vieira, H..; De O. Libardi, R. M.; De Oliveira, E. M.... et al.
Access control is concerned with the policies that manage data sharing activities. Access control plays a crucial role in application areas such as education, health and business. However, most programming languages and programming environments do not naturally provide support for implementing access control policies requiring access control policies for systems to be coded as part of the development effort. Access control management policies are high-level features so having to involve a com...
Ahmad, S.; Abidin, S. Z. Z.; Omar, N.; Reiff-Marganiec, Stephan
The Internet Of Things has emerged, providing an umbrella for the increasing number of heterogeneous Smart Objects that are becoming part of our daily activities. In this scenario, classification approaches are useful to understand differences and identify opportunities of generalization and common solutions, especially when different disciplines are coming together and bringing their individual terms and concepts. We propose a novel model for classifying Smart Objects using capabilities. Thi...
Pérez Hernández, Marco E.; Reiff-Marganiec, Stephan
Fault tolerance techniques can improve the trust of users in service oriented architectures as they can ensure data availability. This paper presents an implementation of a novel fault tolerance mechanism in a SOA architecture which simultaneously provides increased availability and better quality of service. In addition to this mechanism, a service selector using reputation ratings of the architecture components is discussed. The selection is based on information from past transactions of th...
Oliveira, E. M.; Estrella, J. C.; Kuehne, B. T.; Filho, D. M. L.; Adami, L. J.... et al.
This paper presents a semantic approach to custom management of IaaS (Infrastructure as a Service) resources in a cloud computing environment requiring minimal human intervention from both the cloud provider and the user. The proposal differs from other approaches by using autonomic computing and semantic web techniques together to provide a self-configuring and self-optimizing environment that aims to satisfy SLAs (Service Level Agreements). The approach monitors the virtualized resources to...
Nakamura, L. H. V.; Estrella, J. C.; Santana, R. H. C.; Santana, M. J.; Reiff-Marganiec, Stephan
Currently, collaborative environments offer unlimited data sharing for users. Data owners are poorly involved in handling their data for such environment when it deals with data policy. Normally, data access control policy consists of a resource and authorization descriptions which are assigned by the administrator. It is the responsibility of the administrator to set and specify the policy for application services. The policy details are massive and complex for administrator to handle where ...
Ahmad, S.; Omar, N.; Abidin, S. Z. Z.; Reiff-Marganiec, Stephan
The introduction of of web services has led to web service composition being a focus of many researchers. Composing web services using workflows is seen as the most realistic method from an industrial viewpoint. Amongst other method, the use of natural computing methods has been proposed previously to automate web service composition. The need for a fast response when computing the most suitable sequence of services is addressed in this paper. In particular, we propose a novel heuristic immun...
Xu, J.; Reiff-Marganiec, Stephan
Cloud computing is a computing style where resource providers can offer on-demand services in a transparent way and clients usually pay as they go. It introduces a new level of flexibility and scalability for IT users addressing challenges such as the rapid change in IT and the need to reduce cost and time of infrastructure management. However, to be able to offer QoS guarantees without limiting the number of accepted requests, providers must be able to dynamically adjust the available resour...
Batista, B. G.; Estrella, J. C.; Santana, M. J.; Santana, R. H. C.; Reiff-Marganiec, Stephan
The Internet of Things, large scale sensor networks or even in social media, are now well established and their use is growing daily. Usage scenarios in these fields highlight the requirement to process, procure, and provide information with almost zero latency. This work is introducing new concepts for enabling fast communication by limiting information flow through filtering concepts combined with data processing techniques adopted from complex event processing. Specifically we introduce a ...
Reiff-Marganiec, Stephan; Tilly, M.; Janicke, H.
Performing functionality testing in service-oriented architectures is not a trivial task. The difficulty is especially the large number of components that may be present in a SOA such as brokers, providers, service registries, clients, monitoring tools, data storage tools, etc. Thus, in order to facilitate the process of conducting functional testing and capacity planning in service-oriented systems, we present PEESOS. This first version is a functional prototype that offers facilities to ass...
Nunes, L. H.; Vasconcelos Nakamura, L. H.; Tardiole Kuehne, B.; De Oliveira, E. M.; De O Libardi, R. M.... et al.
Over the last years, the complexity and variety of services available on the Internet increased. This fact is leading to the search for efficient techniques of routing client requests to the best server available. A known technique is the application layer anycast (ALA). The main goal of this work is to elaborate efficient ways to provide ALA with quality of service in the context of cloud computing. To achieve this goal, we proposed a new algorithm (GALA, Global Application Layer Anycast). I...
Adami, L. J.; Estrella, J. C.; De Oliveira, E. M.; Reiff- Marganiec, Stephan
Web services are developed independently and deployed in a distributed environment, new service can be obtained by composing existing ones. The rapid introduction of new services also results in undesirable interactions between services. These conflicts are not mismatches of interfaces, but are usually based on the data in the executing instance and therefore runtime management of conflicts in Web services should be considered. We study the problem from the perspective of user’s reven...
Ning, X.; Xu, J.; Xu, N.; Reiff-Marganiec, Stephan
This paper analyzes the execution behavior of web services on devices with limited resources. The experiments compare web services in the Axis2 and CXF frameworks analyzing performance and power consumption. To determine which framework is better suited for service provision, a testing environment and a performance and energy evaluation between them are presented. We show that the Raspberry Pi can be useful in service-oriented applications for different types of tasks. Bringing togeth...
Nunes, L. H.; Nakamura, L. H. V.; De F. Vieira, H.; De O. Libardi, R. M.; De Oliveira, E. M.... et al.
This paper presents a solution to performance issues in the quality of service aware selection of Web services using techniques of parallelism and mechanisms of inference provided by Semantic Web. The results point to a significant improvement in the speed of searching Web services and thus makes the use of semantic resources viable in distributed systems to provide better quality of service to the clients.
Nakamura, L. H. V.; do Prado, P. F.; de O. Libardi, R. M.; Nunes, L. H.; Estrella, J. C.... et al.