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Brazilian Symposium on Computing System Engineering (SBESC)

作者： Margarete De Sá Sérgio Gorender Distributed Systems Laboratory (LaSiD) Graduate Program in Mechatronics (PPGM) Computer Science Institute (IC) and Polytechnic School (EP) Federal University of Bahia (UFBA)

ISBN: (数字)9798331509002

ISBN: (纸本)9798331532857

VANETs make it possible to execute specific vehicular applications, in particular those with the aim of turning traffic safe and avoiding congestion. However, it is difficult to maintain communication between vehicles when these vehicles move dynamically at high speeds. Context-aware systems have been studied as a way to monitor context information from sensors, which can be used by systems to adapt to changes in their environment or in application requirements. This concept is used by VANET protocols and applications in different ways. Quality of Context (QoC) metrics are used to qualify the context information considering different characteristics of sensors and of the information, being a base for systems to decide if it is safe and interesting to use specific information. In this paper, we propose QoC metrics related to the stability of the updating process for a vehicular communication context. In addition, we also analyze the Age QoC metric and show how to calculate it for distinct context information. We simulate scenarios to verify the QoC metrics behavior. The results showed that the proposed QoC metrics can properly qualify the vehicular communication context.

关键词： Measurement Roads Vehicular ad hoc networks Sensor phenomena and characterization Turning systems engineering and theory Stability analysis Sensor systems Reliability Monitoring

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Energy-Efficient eHealth Monitoring with LPWAN

Energy-Efficient eHealth Monitoring with LPWAN

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Brazilian Symposium on Computing System Engineering (SBESC)

作者： Marcelo Alves Guimarães Raimundo José De Araújo Macêdo Distributed Systems Laboratory (LaSiD) Postgraduate Program in Mechatronics (PPGM) / DCI / IC Federal University of Bahia (UFBA) Department of Sciences and Technologies (DCT) State University of Southwest Bahia (UESB)

ISBN: (数字)9798331509002

ISBN: (纸本)9798331532857

This paper presents the design and development of a novel tool for collecting and transmitting clinical data over a Low Power Wide Area Network (LPWAN). The tool features custom-designed integration boards and power management mechanisms tailored explicitly for the cyclical operation of the integrated technologies. Prioritizing effective data transmission while minimizing energy consumption-a critical factor in healthcare applications-the tool employs two key strategies: (1) on/off circuitry for GPS and ECG components to conserve power, and (2) an adaptive power protocol that leverages message acknowledgments and the Received Signal Strength Indicator (RSSI) for dynamic transmission power adjustments. Real-world experiments conducted in a relatively dense environment provided valuable insights into the system's performance under realistic conditions, showing this to be a promising approach to saving energy and optimizing eHealth applications within cyber-physical distributed systems. The fully operational tool now serves as a valuable testbed for further developments in the e-health domain.

关键词： Protocols System performance Power system management systems engineering and theory Energy efficiency Electronic healthcare Received signal strength indicator Monitoring Low-power wide area networks Global Positioning System

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E-THeTA: An Efficient and Adaptive TDMA Approach for Wireless Body Area Networks

E-THeTA: An Efficient and Adaptive TDMA Approach for Wireles...

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Brazilian Symposium on Computing System Engineering (SBESC)

作者： Jorge F. Herculano Luís O. S. de Andrade Willians De P. Pereira Alirio S. de Sá Distributed Systems Laboratory (LaSiD) Graduate Program in Mechatronics (PPGM) Computer Science Institute (IC) and Polytechnic School (EP) Federal University of Bahia (UFBA) Ondina Campus Salvador Bahia Brazil Federal University of Southern Bahia (UFSB) Itabuna Campus Bahia Brazil Sergipe Federal Institute of Education Science and Technology (IFS) Socorro Campus Sergipe Brazil Rondônia Federal Institute of Education Science and Technology (IFRO) Porto Velho Campus Rondônia Brazil

ISBN: (数字)9798331509002

ISBN: (纸本)9798331532857

Several research efforts have proposed adaptive solutions for Time Division Multiple Access (TDMA) to satisfy time requirements and save energy on Wireless Body Area Networks (WBANs) affected by radiofrequency interferences and carrying dynamic traffic. Even with the benefits, most of these solutions waste network bandwidth, decreasing network performance and the ability to recover from some unexpected communication conditions. This paper introduces the E-THeTA, an adaptive and efficient approach based on TDMA crafted to enhance performance, save energy, and efficiently use WBAN bandwidth. Compared to IEEE 802.15.4 and IEEE 802.15.6 standards and other adaptive approaches, the proposed solution reduces message losses, consumes less energy, and maintains low communication latencies in most evaluated scenarios.

关键词： Wireless communication IEEE 802.15 Standard Radio frequency Time division multiple access Adaptive systems Bandwidth Body area networks Standards

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Simple Area Coverage by a Dynamic Set of Unmanned Aerial Vehicles 10

Simple Area Coverage by a Dynamic Set of Unmanned Aerial Veh...

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10th Brazilian Symposium on Computing systems Engineering, SBESC 2020

作者： Pellegrino, Grazieno Mota, Gustavo Assis, Flavio Gorender, Sergio Sa, Alirio LaSiD-Distributed Systems Laboratory Salvador Bahia Brazil PGCOMP-Graduate Program in Computer Science Salvador Bahia Brazil PPGM-Graduate Program in Mechatronics UFBA-Federal University of Bahia DCC-Department of Computer Science Salvador Bahia Brazil

ISBN: (纸本)9781728182865

The coordination of cooperating Unmanned Aerial Vehicles (UAVs) has become an active area of research. The approaches to coordinate these so-called swarms generally include a solution to a class of problems called Area Coverage as a building block. Area coverage problems consist in obtaining information about a certain interest area (commonly a polygon or a polyhedron) using a set of UAVs, generally with decentralized coordination and minimal human intervention. This problem models the requirements of different types of applications, such as in the case of emergencies and disasters, gas leak detection, seeking lost people, among many others. In this paper we describe a specific strategy to coordinate dynamic sets of UAVs to solve a specific area coverage problem. Existing solutions to the problem typically consider a fixed set of UAVs. In dynamic sets, UAVs might enter or leave the set. Beyond describing a specific strategy to the problem, we introduce the framework we are building on top of ROS/Gazebo to implement it. This framework eases the implementation of different strategies for multiple UAVs coordination and the assessment of their quality. © 2020 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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Simple Area Coverage by a Dynamic Set of Unmanned Aerial Vehicles

Simple Area Coverage by a Dynamic Set of Unmanned Aerial Veh...

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Brazilian Symposium on Computing System Engineering (SBESC)

作者： Grazieno Pellegrino Gustavo Mota Flávio Assis Sérgio Gorender Alirio Sá PGCOMP-Graduate Program in Computer Science LaSiD-Distributed Systems Laboratory PPGM-Graduate Program in Mechatronics UFBA-Federal University of Bahia Salvador Bahia Brazil

ISBN: (数字)9781728182865

ISBN: (纸本)9781728182872

关键词： Base stations Sensors Vehicle dynamics Task analysis systems operation Surveillance Software

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A distributed Algorithm to Schedule TSCH Links under the SINR Interference Model

A Distributed Algorithm to Schedule TSCH Links under the SIN...

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Brazilian Symposium on Computing System Engineering (SBESC)

作者： José Carlos Da Silva Flávio Assis UFS - Federal University of Sergipe Sao Cristovao SE BR LaSiD - Distributed Systems Laboratory PPGM - Graduate Program on Mechatronics UFBA - Federal University of Bahia Salvador Brazil

Industrial environments are typically characterised by high levels of interference. Therefore, standards for industrial wireless sensor networks (WirelessHART, ISA 100.11a, and IEEE 802.15.4e) have defined a time division and multichannel-based mode of operation, in which time slots and channel pairs are assigned to links representing communication between nodes. In IEEE 802.15.4e this mode of operation is called Timed Slotted Channel Hopping (TSCH). In this paper we describe a distributed algorithm to define such an assignment for a given wireless network. In particular, the algorithm is efficient, scalable and was developed for the Signal-to-Interference-plus-Noise-Ratio (SINR) model, currently considered the most appropriate to develop and analyse algorithms for wireless networks when interference is taken into consideration. Previous approaches to this problem are mainly centralised, based on a simple (or none) interference model or do not consider multiple physical channels. The described algorithm applies also to the Internet of Things, characterised by high scale and presence of interference.

关键词： Interference Signal to noise ratio Schedules Wireless sensor networks IEEE 802.15 Standard Algorithm design and analysis

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Assessing the benefits of search-based approaches when designing self-adaptive systems: a controlled experiment

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Journal of Software Engineering Research and Development 2015年第1期3卷 1-27页

作者： Sandro S Andrade Raimundo J de A Macêdo Distributed Systems Laboratory (LaSiD) Federal University of Bahia (UFBa) Institute of Mathematics Department of Computer Science Salvador-BA Brazil GSORT Distributed Systems Group Federal Institute of Education Science and Technology of Bahia (IFBa) Department of Computer Science Salvador-BA Brazil

The well-orchestrated use of distilled experience, domain-specific knowledge, and well-informed trade-off decisions is imperative if we are to design effective architectures for complex software-intensive systems. In particular, designing modern self-adaptive systems requires intricate decision-making over a remarkably complex problem space and a vast array of solution mechanisms. Nowadays, a large number of approaches tackle the issue of endowing software systems with self-adaptive behavior from different perspectives and under diverse assumptions, making it harder for architects to make judicious decisions about design alternatives and quality attributes trade-offs. It has currently been claimed that search-based software design approaches may improve the quality of resulting artifacts and the productivity of design processes, as a consequence of promoting a more comprehensive and systematic representation of design knowledge and preventing design bias and false intuition. To the best of our knowledge, no empirical studies have been performed to provide sound evidence of such claim in the self-adaptive systems domain. This paper reports the results of a quasi-experiment performed with 24 students of a graduate program in distributed and Ubiquitous Computing. The experiment evaluated the design of self-adaptive systems using a search-based approach proposed by us, in contrast to the use of a non-automated approach based on architectural styles catalogs. The goal was to investigate to which extent the adoption of search-based design approaches impacts on the effectiveness and complexity of resulting architectures. In addition, we also analyzed the approach’s potential for leveraging the acquisition of distilled design knowledge. Our findings show that search-based approaches can improve the effectiveness of resulting self-adaptive systems architectures and reduce their design complexity. We found no evidence regarding the approach’s potential for leveraging the acqu

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Maximum lifetime broadcast in mobile sensor networks 1

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12th International Conference on Ad-hoc, Mobile and Wireless Networks, ADHOC-NOW 2013

作者： Nunes, Bruno Barboza, Frederico Assis, Flávio LaSiD - Distributed Systems Laboratory DCC - Department of Computer Science UFBA - Federal University of Bahia Salvador Bahia Brazil

ISBN: (数字)9783642392474

ISBN: (纸本)9783642392467

In this paper we investigate the Maximum Lifetime Broadcast (MLB) problem, i.e. the problem of extending network lifetime when a series of broadcast operations is executed, in sensor networks with mobile nodes. For this problem, we present two localized algorithms (nodes use only 2-hop information), namely LPrim and LMCP, which are based on trees with minimum highest cost edges and shortest paths trees, respectively. The algorithms were evaluated through simulations under three distinct mobility models and compared against common broadcasting techniques (broadcasting based on a Connected Dominating Set and Flooding). According to our experiments, LPrim outperformed alternative solutions in terms of the number of successfully executed broadcasts (network lifetime) and in terms of the energy consumed by broadcast. © 2013 Springer-Verlag.

关键词： Sensor nodes

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A localized algorithm based on minimum cost arborescences for the MECBS problem with asymmetric edge costs

A localized algorithm based on minimum cost arborescences fo...

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3rd International ICST Conference on Ad Hoc Networks, ADHOCNETS 2011

作者： Barboza, Frederico Assis, Flávio LaSiD - Distributed Systems Laboratory DCC - Department of Computer Science UFBA - Federal University of Bahia Salvador Bahia Brazil

ISBN: (纸本)9783642290954

In this paper we describe a (distributed) localized approximation algorithm for the MECBS (Minimum Energy Consumption Broadcast Subgraph) problem with asymmetric edge costs, called LMCA (Localized algorithm for energy-efficient broadcast based on Local Minimum Cost Arborescences). Given a directed weighted graph G = (V, E) with edge weight function w and a source node s, the MECBS problem consists of finding a range assignment to V such that the induced graph contains a spanning directed tree rooted at s with minimized cost. This problem can be efficiently solved for some specific cases, but it is NP-hard in the general case. To the best of our knowledge, LMCA is the first localized algorithm to the MECBS problem with asymmetric edge costs (without restricting the way how edge costs might be asymmetric). We compared LMCA with blind flooding and with two alternative solutions we designed for the problem, LMCP and LBIPAsym (a variation of LBIP for the case of asymmetric edge costs). In our experiments, LMCA outperformed these algorithms. We additionally present and evaluate two slight variations of LMCA, called LMCAc and LMCAfl. © 2012 ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

关键词： Approximation algorithms

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Robot ontologies for sensor- and Image-guided surgery

Robot ontologies for sensor- and Image-guided surgery

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International Workshop on Robot Sensing (ROSE)

作者： Tamás Haidegger Marcos Barreto Paulo J. S. Goncalves Maki K. Habib S. Veera Ragavan Howard Li Alberto Vaccarella Roberta Perrone Edson Prestes Austrian Center for Medical Innov. and Techn. (ACMIT) Wiener Neustadt Austria UFBA Distributed Systems Laboratory (LaSiD) Brazil IDMEC Center of Intelligent Systems Portugal The American University in Cairo Cairo Egypt Monash University Selangor Malaysia Dept. of Electrical and Computer Engineering University of New Brunswick Canada Dept. of Electronics Information and Bioengineering (DEIB) NearLab Medical Robotics Milan Italy UFRGS Instituto de Informática Brazil

Robots and robotics are becoming more complex and flexible, due to technological advancement, improved sensing capabilities and machine intelligence. Service robots target a wide range of applications, relying on advanced Human-Robot Interaction. Medical robotics is becoming a leading application area within, and the number of surgical, rehabilitation and hospital assistance robots is rising rapidly. However, the complexity of the medical environment has been a major barrier, preventing a wider use of robotic technology, thus mostly teleoperated, human-in-the-loop control solutions emerged so far. Providing smarter and better medical robots requires a systematic approach in describing and translating human processes for the robots. It is believed that ontologies can bridge human cognitive understanding and robotic reasoning (machine intelligence). Besides, ontologies serve as a tool and method to assess the added value robotic technology brings into the medical environment. The purpose of this paper is to identify relevant ontology research in medical robotic, and to review the state-of-the-art. It focuses on the surgical domain, fundamental terminology and interactions are described for two example applications in neurosurgery and orthopaedics.

关键词： Robot sensing systems Surgery Lead Ontologies Biomedical optical imaging

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