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- Survey on the Characterization and Classification of Wireless Sensor Network ApplicationsPublication . Borges, Luís M.; Velez, Fernando J.; Lebres, António S.Nowadays, wireless sensor network (WSN) users are demanding more and more in terms of choice and diversity of applications. Hence, as the diversity of applications is increasing, it is worthwhile to propose a structure for the set of characterization parameters that allows sketching a taxonomy for WSN applications. This taxonomy is established via an application-oriented approach, identifying the specific services offered by each application. In this survey, we fill this gap in the WSN literature by describing the characterization parameters, organized into six different categories. Our taxonomy for application classification is centered on the different sets of parameters that have high impact on a given future WSN application. Typical attributes and values from related research works are considered as a reference, but in this survey, we propose inter- and intra-connections among the considered application groups. Based on these connections, new application groups have been proposed for applications that share common characterization parameters, along with a holistic overview of WSN application taxonomy and the discussion of the three generations of WSNs toward communication between things and the Internet of Things , as well as future trends for the development of WSN applications. Moreover, detailed parameters from different projects and authors in the field of WSNs are joined together for comparison purposes.
- Wireless Sensor and Actuator Networks Services and Applications: Characterisation and Classification TaxonomiesPublication . Borges, Luís M.; Velez, Fernando José; Lebres, António S.Nowadays Wireless Sensor Networks (WSN) users are becoming more exigent when choosing services for a certain WSN application. This paper describes the characteristics of WSN services and applications, splitting them into six main characteristics and each main characteristic is identified by specific parameters that identify the main characteristic. For each parameter a description is made in order to better understand how services are described and differentiate from each other and examples are given, referring the importance of these parameters in the services that are offered to the user. The gathering of all these parameters allowed us to sketch up taxonomy for the services in WSN regarding the applications, allowing the user to choose the application he/she wants based in these categories whilst identifying the services offered by the application. Future work will aim the detailed characterization of services offered to the main areas of WSNs considering these parameters and also on others parameters yet to be included.
- Wireless Flex Sensor Belt Networks for Foetal Movement Monitoring in Low Risk PregnanciesPublication . Borges, Luís M.; Barroca, Norberto; Zamith, Fernando; Lebres, António SérgioIn this work two flex sensor belts were produced to count the foetal movements in the last four weeks of pregnancy. While one is a standalone solution the other is a wireless flex sensor belt network one. A description of the type of sensors is followed by the discussion of the different types of acquisition and data treatment methodologies. The application to display the deformation angles is presented as well. The wireless sensor network solution is based on the IEEE 802.15.4 standard, and the hierarchical wireless network solutions include a Wi-Fi layer. Preliminary results highlight the need for accounting for mother respiration movements and actual experiences with pregnant woman will facilitate tuning the threshold-trigger, to improve the detection performance.
- Overview of Progress in Smart-Clothing for Health Monitoring and Sport ApplicationsPublication . Borges, Luís M.; Rente, Andreia; Velez, Fernando José; Salvado, Luísa R.; Lebres, António S.Smart-Clothing is a project that combines research in textiles materials and wireless sensor and actuator networks in the context of human body monitoring with statistical methods for the data analysis and treatment. This project aims mainly to aid in the monitoring of the foetal movement in the last four weeks of pregnancy. Besides the integration of sensors in the garment there will be needed a hierarchical communication system that allows the delivery of the data collected from the garment that the pregnant is wearing to the doctor. The pregnant can be either at home or in the hospital. In the first stage of the project tests are being made using several types of sensors integrated in a belt in order to choose the one that is more reliable for the detection of foetal movement. Another sensing task is the manufacture of the electrodes for the electrocardiogram (ECG) system. At this point, the electrodes for the ECG are already made and working. The testing of the sensor for the detection of foetal movement is still being done.
- Wearable Sensors for Foetal Movement Monitoring in Low Risk PregnanciesPublication . Borges, Luís M.; Araújo, Pedro; Lebres, António S.; Rente, Andreia; Salvado, Rita; Velez, Fernando J.; Martinez-de-Oliveira, J.; Barroca, Norberto; Ferro, João MiguelIn low risk pregnancies, the continuous monitoring of the foetal health is based on traditional protocols for counting the foetal movements felt by the mother. Although the maternal perception is a relevant characteristic for the evaluation of the foetal health, this kind of monitoring is hard to accomplish and being subjective can induce into errors due to mother’s anxiety and lack of concentration. Furthermore, the majority of foetal fatalities occur during the last weeks of low risk pregnancies. Therefore, it is important to obtain a universal electronic obstetric tracing, allowing for the identification of sudden changes in the foetus health, by continuously monitoring the foetus movements. The Smart-Clothing project aim has been the development of easy-to-wear belts with a telemedicine system for this purpose. One of the tried solutions is the Flex sensor belt system, which guarantees real-time and continuous foetal monitoring while creating effective interfaces for querying sensor data and store all the medical record (which can later be accessed by health professionals). Another developed belt has piezoelectric sensors incorporated onto it. The piezoelectric sensor belt has shown a high capacity to detect foetal movements, isolating them from external interferences.
- Energy-Aware Wireless Sensor Networks MAC Modelling and Simulation with Efficient TransceiversPublication . Barroca, Norberto; Velez, Fernando J.; Ferro, João Miguel; Mihovska, Albena Dimitrova; Lebres, António S.This paper addresses an analytical model that may be applied to different Wireless Sensor Networks (WSNs) Medium Access Control (MAC) protocols using different efficient transceivers. Our model accounts for the impact of several simultaneous factors, including periodic receive/transmit and sleep cycles, the length of the transmitted packet and data rate. The Sensor Block Acknowledgement MAC, a new innovative WSNs MAC protocol that uses a Block Acknowledgement scheme to achieve energy efficiency, is proposed as well. Our implementation takes into account the average delay, which can be clearly reduced when a Block Acknowledgement Scheme is used. In terms of energy consumption and average delay the efficient radio transceivers that operate in the 2.4GHz band have better results that the ones that use the 900MHz band. Adaptive listening (AL) enables radio transceivers to stay alert after the communication between two neighbour nodes before going to sleep, allowing for energy saving when synchronisation is involved.
- Frame Capture and Reliability Based Decider Implementation in the MiXiM IEEE 802.15.4 FrameworkPublication . Borges, Luís M.; Velez, Fernando J.; Barroca, Norberto; Lebres, AntónioThe task of properly modelling the physical (PHY) layer constitutes the most challenging endeavor in wireless networks simulation. Unfortunately, today, the majority of the wireless sensor network (WSN) simulators consider a simple model for the PHY frame reception, which does not account for emerging research on the frame capture (FC) effect. In this paper, we present enhancements for the PHY layer model for the IEEE 802.15.4 standard employed in the MiXiM framework, to account for the FC effect within WSN-based simulations. These improvements are as follows: i) proposal of a formulation for the PHY layer packet reception based on a reliability concept, identified as the Enhanced Reliability Decision Algorithm, which guarantees the delivery of a packet received by the PHY layer to the medium access control (MAC) layer, with a certain value for the reliability (0.9 and 0.99); ii) different frame overlapping scenarios, and iii) different values for the thresholds to decide frame recovery. The work includes the description, implementation and performance evaluation of the proposed decision algorithm, jointly with the FC effect, in the MiXiM framework simulator, for basic MAC and scheduled channel polling (SCP) MAC protocols. Based on the simulation results, the proposed approach can significantly improve simulation accuracy and provide a PHY decision algorithm that guarantees, with a certain reliability, the delivery of frames to the MAC layer.
- Smart-clothing wireless flex sensor belt network for foetal health monitoringPublication . Borges, Luís M.; Barroca, Norberto; Velez, Fernando J.; Lebres, AntónioIn the past years low power circuits design and networking techniques not only reduce the total power, requirements for Wireless Sensor Networks (WSNs) but also allow for supporting more complexity. In this paper we present solutions for WSN applications, and design aspects in the context of patient monitoring. The solution presented whose primary function is to collect the vital data remotely from the various sensors in low-rate wireless personal area network (LR-WPAN) is based on the IEEE 802.15.4 standard. It also will includes a Wi-Fi Layer in the context of hybrid networks. The application being dealt here consist of several flex sensors attached to a wearable monitoring belt, and allows for monitoring the foetal movements for a pregnant woman.
- Taxonomy for Wireless Sensor Networks Services Characterisation and ClassificationPublication . Borges, Luís M.; Velez, Fernando José; Lebres, António S.Nowadays, the users of Wireless Sensor and Actuator Networks (WSAN) are becoming more and more demanding in terms of choice and diversity of applications, and the identification of their characterization parameters is thus in order. This paper describes the WSAN characterization parameters and is an update of a previous work, but new parameters were added and new characteristics were proposed. The gathering of all these parameters allowed us to sketch up taxonomy for WSAN via an application-oriented approach, identifying the services offered by each application. For comparison purposes, tables with details from different projects in the field of WSAN are presented.
- Performance Evaluation of the Schedule Channel Polling MAC Protocol applied to Health Monitoring in the Context of IEEE 802.15.4Publication . Borges, Luís M.; Velez, Fernando J.; Lebres, António S.The field of Wireless Body Area Networks (WBANs) has been growing considerably in the last years. A WBAN enables to monitor vital body signs through the placement of sensors on the human body and offers to patients more flexibility and mobility. In this paper, we examine the Quality of Service (QoS) performance metrics evaluation (single and multi-hop topology) of the Scheduled Channel Polling-MAC (SCP) protocol, whilst considering the IEEE 802.15.4 standard in the context of remote patient monitoring applications. We applied the MiXiM Framework (based on OMNeT++) in the network simulations. Our simulations results help to clarify some missing aspects in the original SCP protocol description. The IEEE 802.15.4 compliant Medium Access Control (MAC) is compared with the MAC layer in the absence of the IEEE 802.15.4, leading to similar values for the throughput in saturated conditions. The results also show that considering low duty cycles, the use of IEEE 802.15.4 leads to lower energy. For multi-hop experiments in high duty cycles, the energy consumptions are lower with the AT86RF231 transceiver, comparing with the CC1100 and CC2420. Future work includes the adaptation of the SCP protocol to the IEEE 802.15.6 standard, which has been specially developed to optimize the WBAN performance at the physical and MAC layers.