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Publications

Publications by Nuno Alexandre Pereira

2007

Static-Priority Scheduling over Wireless Networks with Multiple Broadcast Domains

Authors
Pereira, N; Andersson, B; Tovar, E; Rowe, A;

Publication
Proceedings of the 28th IEEE Real-Time Systems Symposium (RTSS 2007), 3-6 December 2007, Tucson, Arizona, USA

Abstract

2004

Timeliness in COTS factory-floor distributed systems: What role for simulation?

Authors
Pereira, N; Tovar, E; Pinho, LM;

Publication
WFCS 2004: IEEE INTERNATIONAL WORKSHOP ON FACTORY COMMUNICATION SYSTEMS, PROCEEDINGS

Abstract
In the past few years, a significant amount of work has been devoted to the timing analysis of Ethernet-based technologies. However, none of these address the problem of timeliness evaluation at a holistic level. This paper describes a research framework embracing this objective. It is advocated that, simulation models can be a powerful tool, not only for timeliness evaluation, but also to enable the introduction of less pessimistic assumptions in an analytical response time approach, which, most often, are afflicted with simplifications leading to pessimistic assumptions and, therefore. delusive results. To this end, we address a few inter-linked research topics with the purpose of setting a framework for developing tools suitable to extract temporal properties of Commercial-Off-The-Shelf (COTS) factory-floor communication systems.

2023

From a Visual Scene to a Virtual Representation: A Cross-Domain Review

Authors
Pereira, A; Carvalho, P; Pereira, N; Viana, P; Corte-Real, L;

Publication
IEEE ACCESS

Abstract
The widespread use of smartphones and other low-cost equipment as recording devices, the massive growth in bandwidth, and the ever-growing demand for new applications with enhanced capabilities, made visual data a must in several scenarios, including surveillance, sports, retail, entertainment, and intelligent vehicles. Despite significant advances in analyzing and extracting data from images and video, there is a lack of solutions able to analyze and semantically describe the information in the visual scene so that it can be efficiently used and repurposed. Scientific contributions have focused on individual aspects or addressing specific problems and application areas, and no cross-domain solution is available to implement a complete system that enables information passing between cross-cutting algorithms. This paper analyses the problem from an end-to-end perspective, i.e., from the visual scene analysis to the representation of information in a virtual environment, including how the extracted data can be described and stored. A simple processing pipeline is introduced to set up a structure for discussing challenges and opportunities in different steps of the entire process, allowing to identify current gaps in the literature. The work reviews various technologies specifically from the perspective of their applicability to an end-to-end pipeline for scene analysis and synthesis, along with an extensive analysis of datasets for relevant tasks.

2014

Security vulnerabilities and risks in industrial usage of wireless communication

Authors
Plosz, S; Farshad, A; Tauber, M; Lesjak, C; Ruprechter, T; Pereira, N;

Publication
19th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2014

Abstract
Due to its availability and low cost, the use of wireless communication technologies increases in domains beyond the originally intended usage areas, e.g. M2M communication in industrial applications. Such industrial applications often have specific security requirements. Hence, it is important to understand the characteristics of such applications and evaluate the vulnerabilities bearing the highest risk in this context. We present a comprehensive overview of security issues and features in existing WLAN, NFC and ZigBee standards, investigating the usage characteristics of these standards in industrial environments. We apply standard risk assessment methods to identify vulnerabilities with the highest risk across multiple technologies. We present a threat catalogue, conclude in which direction new mitigation methods should progress and how security analysis methods should be extended to meet requirements in the M2M domain. © 2014 IEEE.

2014

Experiments with a Sensing Platform for High Visibility of the Data Center

Authors
Loureiro, J; Pereira, N; Santos, P; Tovar, E;

Publication
Internet of Things Based on Smart Objects, Technology, Middleware and Applications

Abstract
Data centers are large energy consumers and a substantial portion of this power consumption is due to the control of physical parameters, which bring the need of high efficiency environmental control systems. In this work, we describe a hardware sensing platform specifically tailored to collect physical parameters (temperature, pressure, humidity and power consumption) in large data centers. Our system architecture is composed of Smart Objects, the datacenter racks, that cooperate to contribute for the overall goal of finding opportunities to optimize energy consumption and achieving energy-efficient data centers.We also introduce an analysis of the delay to obtain the sensing data from the sensor network. This analysis provides an insight into the time scales supported by our platform, and also allows to study the delay for different data center topologies. Finally, we exemplify some capabilities of the system with a real deployment. © Springer International Publishing Switzerland 2014.

2014

Poster abstract: A harmony of sensors: Achieving determinism in multi-application sensor networks

Authors
Gupta, V; Tovar, E; Pereira, N; Rajkumar, RR;

Publication
IPSN 2014 - Proceedings of the 13th International Symposium on Information Processing in Sensor Networks (Part of CPS Week)

Abstract
Several concurrent applications running on a sensor network may cause a node to transmit packets at distinct periods, which increases the radio-switching rate and has significant impact in terms of the overall energy consumption. We propose to batch the transmissions together by defining a harmonizing period to align the transmissions from multiple applications at periodic boundaries. This harmonizing period is then leveraged to design a distributed protocol called Network-Harmonized Scheduling (NHS) that coordinates transmissions across nodes and provides real-time guarantees in a multi-hop network. © 2014 IEEE.

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