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Publications

2015

BYOD NETWORK: Enhancing Security through Trust–Aided Access Control Mechanisms

Authors
Nwebonyi, FN; The Society of Digital Information and Wireless Communication,;

Publication
International Journal of Cyber-Security and Digital Forensics

Abstract

2015

Adaptive Broadcast Cancellation Query Mechanism for Unstructured Networks

Authors
Lima, R; Baquero, C; Miranda, H;

Publication
2015 9th International Conference on Next Generation Mobile Applications, Services and Technologies (NGMAST 2015)

Abstract
The availability of cheap wireless sensors boosted the emergence of unstructured networks using wireless technologies with decentralised administration. However, a simple task such as learning the temperature needs a discovery service to find a thermometer among all the sensors. In general, resource discovery relies on flooding mechanisms that waste energy and compromises system availability. Energy efficient strategies limit the exploration area, but with a significant impact on latency. The paper proposes ABC (Adaptive Broadcast Cancellation), a new algorithm that uses the knowledge acquired in previous discoveries to accelerate queries towards the resource. Knowledge is stored in a variation of Bloom filters, thus contributing for an efficient utilization of the sensors limited memory.

2015

Curvature sensing using an added-signal in a fiber-optic cavity ring-down system

Authors
Silva, SO; Biswas, P; Bandyopadhyay, S; Jorge, PA; Marques, MB; Frazao, O;

Publication
24TH INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
This work presents a fiber-optic Cavity Ring-Down (CRD) configuration using an added-signal for curvature sensing. An Optical Time-Domain Reflectometer (OTDR) was used to send impulses down into the fiber loop cavity, inside of which a long period grating (LPG) was placed to act as sensing device. The added-signal was obtained by the sum of several conventional CRD impulses, thus providing an improvement on the curvature sensitivity when compared to the conventional CRD signal processing. Sensitivity to applied curvature of 15.3 mu s/m(-1) was obtained. This result was found to be 20-fold the one obtained for the conventional CRD signal processing.

2015

Identifying useful actions to improve team resilience in information systems projects

Authors
Amaral, A; Fernandes, G; Varajao, J;

Publication
CONFERENCE ON ENTERPRISE INFORMATION SYSTEMS/INTERNATIONAL CONFERENCE ON PROJECT MANAGEMENT/CONFERENCE ON HEALTH AND SOCIAL CARE INFORMATION SYSTEMS AND TECHNOLOGIES, CENTERIS/PROJMAN / HCIST 2015

Abstract
Due to today's business environment demands organizations need to create teams to perform work in projects, with quality, within time and budget. Therefore, teams play a very important role in the organizational development, by creating conditions that enable to overcome difficulties and to promote the improvement of the organizational overall performance. Hence the relevance of studying the project teams resilience, identifying the actions that can influence the project development and its final outcomes. The resilience of a team can be defined as the team's ability to deal with problems, overcome obstacles, or resist the pressure of adverse situations, without entering into rupture. This research, focused on team resilience, firstly involved a literature review, followed by brainstorming sessions, resulting in a preliminary list of useful actions to improve project team resilience. Then, a survey was administered in order to identify the most useful actions perceived from the identified list. Completed questionnaires were received from 115 team members of information technologies/information systems projects being developed in an academic setting. By identifying the most useful actions perceived, as those having the highest potential for increasing project team resilience, practitioners and organizations can set their priorities towards improving team resilience. The results showed that the top ten list of useful actions identified is composed by very well-known and recognized actions, such as the promotion of collaboration and solidarity among project team members, and the recognition, appreciation and use of the talents and competencies of each team member. (C) 2015 Published by Elsevier B.V.

2015

Improving ns-3 emulation support in real-world networking scenarios

Authors
Fontes, H; Campos, R; Ricardo, M;

Publication
Proceedings of the 8th International Conference on Simulation Tools and Techniques, Athens, Greece, August 24-26, 2015

Abstract
A common problem in networking research and development is the duplicate effort of writing simulation and implementation code. This duplication can be avoided through the use of fast-prototyping methodologies, which enable reusing simulation code in real prototyping and in production environments. Although this functionality is already available by using ns-3 emulation, there are still limitations regarding the support of real network interfaces and easy configuration of the network settings, such as IP and MAC addresses. In this paper we propose an improved version of the ns-3 emulation component by introducing new functionalities that address these limitations. The new functionalities include the support of new types of real network interfaces and the easier integration of emulation nodes with existing networks by means of a new auto-configuration mechanism for ns-3 nodes. Experimental results obtained in a laboratorial testbed and in a real vehicular network testbed demonstrate the new functionalities proper operation, and their backwards compatibility with previously coded ns-3 scenarios. Copyright © 2015 ICST.

2015

Robust and Accurate Localization System for Mobile Manipulators in Cluttered Environments

Authors
Costa, CM; Sobreira, HM; Sousa, AJ; Veiga, GM;

Publication
2015 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY (ICIT)

Abstract
Autonomous robots play a pivotal role in improving productivity and reducing operational costs. They excel at both precision and speed in repetitive jobs and can cooperate with humans in complex tasks within dynamic environments. Self-localization is critical to any robot that must navigate or manipulate the environment. To solve this problem, a modular localization system suitable for mobile manipulators was developed. By using LIDAR data the proposed system is capable of achieving less than a centimeter in translation error and less than a degree in rotation error while requiring only 5 to 25 milliseconds of processing time. The system was tested in two different robot platforms at different velocities and in several cluttered and dynamic environments. It demonstrated high accuracy while performing pose tracking and high reliability when estimating the initial pose using feature matching. No artificial landmarks are required and it is able to adjust its operation rate in order to use very few hardware resources when a mobile robot is not moving.

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