Proximal business intelligence on the semantic web

This is the post-print version of this article. The official version can be accessed from the link below - Copyright @ 2010 Springer.Ubiquitous information systems (UBIS) extend current Information System thinking to explicitly differentiate technology between devices and software components with relation to people and process. Adapting business data and management information to support specific user actions in context is an ongoing topic of research. Approaches typically focus on providing mechanisms to improve specific information access and transcoding but not on how the information can be accessed in a mobile, dynamic and ad-hoc manner. Although web ontology has been used to facilitate the loading of data warehouses, less research has been carried out on ontology based mobile reporting. This paper explores how business data can be modeled and accessed using the web ontology language and then re-used to provide the invisibility of pervasive access; uncovering more effective architectural models for adaptive information system strategies of this type. This exploratory work is guided in part by a vision of business intelligence that is highly distributed, mobile and fluid, adapting to sensory understanding of the underlying environment in which it operates. A proof-of concept mobile and ambient data access architecture is developed in order to further test the viability of such an approach. The paper concludes with an ontology engineering framework for systems of this type – named UBIS-ONTO

Faithful reproduction of network experiments

The proliferation of cloud computing has compelled the research community to rethink fundamental aspects of network systems and architectures. However, the tools commonly used to evaluate new ideas have not kept abreast of the latest developments. Common simulation and emulation frameworks fail to provide scalability, fidelity, reproducibility and execute unmodified code, all at the same time. We present SELENA, a Xen-based network emulation framework that offers fully reproducible experiments via its automation interface and supports the use of unmodified guest operating systems. This allows out-of-the-box compatibility with common applications and OS components, such as network stacks and filesystems. In order to faithfully emulate faster and larger networks, SELENA adopts the technique of time-dilation and transparently slows down the passage of time for guest operating systems. This technique effectively virtualizes the availability of host’s hardware resources and allows the replication of scenarios with increased I/O and computational demands. Users can directly control the tradeoff between fidelity and running-times via intuitive tuning knobs. We evaluate the ability of SELENA to faithfully replicate the behaviour of real systems and compare it against existing popular experimentation platforms. Our results suggest that SELENA can accurately model networks with aggregate link speeds of 44 Gbps or more, while improving by four times the execution time in comparison to ns3 and exhibits near-linear scaling properties.This is the author accepted manuscript. The final version is available from ACM via http://dx.doi.org/10.1145/2658260.265827

Characterization and Identification of Cloudified Mobile Network Performance Bottlenecks

This study is a first attempt to experimentally explore the range of performance bottlenecks that 5G mobile networks can experience. To this end, we leverage a wide range of measurements obtained with a prototype testbed that captures the key aspects of a cloudified mobile network. We investigate the relevance of the metrics and a number of approaches to accurately and efficiently identify bottlenecks across the different locations of the network and layers of the system architecture. Our findings validate the complexity of this task in the multi-layered architecture and highlight the need for novel monitoring approaches that intelligently fuse metrics across network layers and functions. In particular, we find that distributed analytics performs reasonably well both in terms of bottleneck identification accuracy and incurred computational and communication overhead.Comment: 17 pages, 16 figures, documentclass[journal,comsoc]{IEEEtran}, corrected titl

Analysis of source code metrics from ns-2 and ns-3 network simulators

Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each other as they share common background, concepts and similar aims. Ns-3 is still under development, but it offers some interesting characteristics for developers while ns-2 still has a large user base. While other studies have compared different network simulators, focusing on performance measurements, in this paper we adopted a different approach by focusing on technical characteristics and using software metrics to obtain useful conclusions. We chose ns-2 and ns-3 for our case study because of the popularity of the former in research and the increasing use of the latter. This reflects the current situation where ns-3 has emerged as a viable alternative to ns-2 due to its features and design. The paper assesses the current state of both projects and their respective evolution supported by the measurements obtained from a broad set of software metrics. By considering other qualitative characteristics we obtained a summary of technical features of both simulators including, architectural design, software dependencies or documentation policies.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0

SAFE: Simulation Automation Framework for Experiments

The workflow of a network simulation study requires adherence to best practices in methodology so that results are credible and reproducible by third parties. The opportunities for one to introduce errors start at model description and permeate the process through to the reporting of results. The literature indicates that even publications in respected venues include inadvertent mistakes and poor application of methodology. When experts are liable to fail, it is unreasonable to expect that students would fare any better. This paper presents a system designed to provide guidance for inexperienced users of the popular ns-3 network simulator. SAFE automates the workflow from the initialization of model parameters, to the parallelized execution of experiments, to the processing and persistent storage of output data, and to graphical visualization of results. We discuss the architecture and the implementation of the system in the context of similar contributions in the literature

Une approche générique pour l'automatisation des expériences sur les réseaux informatiques

This thesis proposes a generic approach to automate network experiments for scenarios involving any networking technology on any type of network evaluation platform. The proposed approach is based on abstracting the experiment life cycle of the evaluation platforms into generic steps from which a generic experiment model and experimentation primitives are derived. A generic experimentation architecture is proposed, composed of an experiment model, a programmable experiment interface and an orchestration algorithm that can be adapted to network simulators, emulators and testbeds alike. The feasibility of the approach is demonstrated through the implementation of a framework capable of automating experiments using any combination of these platforms. Three main aspects of the framework are evaluated: its extensibility to support any type of platform, its efficiency to orchestrate experiments and its flexibility to support diverse use cases including education, platform management and experimentation with multiple platforms. The results show that the proposed approach can be used to efficiently automate experimentation on diverse platforms for a wide range of scenarios.Cette thèse propose une approche générique pour automatiser des expériences sur des réseaux quelle que soit la technologie utilisée ou le type de plate-forme d'évaluation. L'approche proposée est basée sur l'abstraction du cycle de vie de l'expérience en étapes génériques à partir desquelles un modèle d'expérience et des primitives d'expérimentation sont dérivés. Une architecture générique d'expérimentation est proposée, composée d'un modèle d'expérience générique, d'une interface pour programmer des expériences et d'un algorithme d'orchestration qui peux être adapté aux simulateurs, émulateurs et bancs d'essai de réseaux. La faisabilité de cette approche est démontrée par la mise en œuvre d'un framework capable d'automatiser des expériences sur toute combinaison de ces plateformes. Trois aspects principaux du framework sont évalués : son extensibilité pour s'adapter à tout type de plate-forme, son efficacité pour orchestrer des expériences et sa flexibilité pour permettre des cas d'utilisation divers, y compris l'enseignement, la gestion des plate-formes et l'expérimentation avec des plates-formes multiples. Les résultats montrent que l'approche proposée peut être utilisée pour automatiser efficacement l'expérimentation sur les plates-formes d'évaluation hétérogènes et pour un éventail de scénarios variés

Experimentation made easy with the AMazING panel

Experimental testbeds for evaluating solutions in computer networks, are today required as a complement to simulation and emulation. As these testbeds become larger, and accessible to a broader universe of the research community, dedicated management tools become mandatory. These tools ease the complex management of the testbed specific resources, while providing an environment for researchers to define their experiments with large flexibility. While there are currently several management tools, the research community is still lacking tools that smooth the experimentation workflow. These were key aspects that we considered when developing the management infrastructure for our wireless testbed[4] (AMazING). We developed a experimentation support framework supported by an attractive GUI, automation and scripting capabilities, as well as experiment versioning and integrated result gathering and analysis