Performance assessment of mobility solutions for IPv6-based healthcare wireless sensor networks

This thesis focuses on the study of mobile wireless sensor networks applied to healthcare scenarios. The promotion of better quality-of-life for hospitalized patients is addressed in this research work with a solution that can help these patients to keep their mobility (if possible). The solution proposed allows remote monitoring and control of patients’ health in real-time and without interruptions. Small sensor nodes able to collect and send wirelessly the health parameters allow for the control of the patients' health condition. A network infrastructure, composed by several access points, allows the connection of the sensor nodes (carried by the patients) to remote healthcare providers. To ensure continuous access to sensor nodes special attention should be dedicated to manage the transition of these sensor nodes between different access points’ coverage areas. The process of changing an access point attachment of a sensor node is called handover. In that context, this thesis proposes a new handover mechanism that can ensure continuous connection to mobile sensor nodes in a healthcare wireless sensor network. Due to the limitations of sensor nodes’ resources, namely available energy (these sensor nodes are typically powered by small batteries), the proposed mechanism pays a special attention in the optimization of energy consumption. To achieve this optimization, part of this work is dedicated to the construction of a small sensor node. The handover mechanism proposed in this work is called Hand4MAC (handover mechanism for MAC layer). This mechanism is compared with other mechanisms commonly used in handover management. The Hand4MAC mechanism is deployed and validated through by simulation and in a real testbed. The scenarios used for the validation reproduces a hospital ward. The performance evaluation is focused in the percentage of time that senor nodes are accessible to the network while traveling across several access points’ coverage areas and the energy expenditures in handover processes. The experiments performed take into account various parameters that are the following: number of sent messages, number of received messages, multicast message usage, energy consumption, number of sensor nodes present in the scenario, velocity of sensor nodes, and time-to-live value. In both simulation and real testbed, the Hand4MAC mechanism is shown to perform better than all the other handover mechanisms tested. In this comparison it was only considered the most promising handover mechanisms proposed in the literature.Fundação para a Ciência e a Tecnologia (FCT

Detecting and monitoring the development stages of wild flowers and plants using computer vision: approaches, challenges and opportunities

Wild flowers and plants play an important role in protecting biodiversity and providing various ecosystem services. However, some of them are endangered or threatened and are entitled to preservation and protection. This study represents a first step to develop a computer vision system and a supporting mobile app for detecting and monitoring the development stages of wild flowers and plants, aiming to contribute to their preservation. It first introduces the related concepts. Then, surveys related work and categorizes existing solutions presenting their key features, strengths, and limitations. The most promising solutions and techniques are identified. Insights on open issues and research directions in the topic are also provided. This paper paves the way to a wider adoption of recent results in computer vision techniques in this field and for the proposal of a mobile application that uses YOLO convolutional neural networks to detect the stages of development of wild flowers and plants

Power saving MAC protocols in wireless sensor networks: a survey

In a wireless sensor network, energy is almost always the greatest limitation. Energy sources are restricted in many of the environments where nodes are deployed, limiting them to the use of batteries for power. Therefore, conserving energy is supremely important, however, such a task poses many challenges to hardware and protocol design. One of the greatest problems faced is reducing the energy consumption of the communications systems, which represents a substantial amount of the total consumption. This paper surveys the most recent schemes designed to reduce the communications module energy consumption with a focus on novel MAC protocols for ad-hoc wireless sensor networks. It initially describes the many challenges involved, then it analyses each protocol individually. Finally, the presented protocols are compared and the issues that remain open are raised for further research

Communication tools with intra-body sensors

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to the lack of an appropriate technology, medical research devoted to studying correlations of such body parameters with certain woman’s body phenomena could not obtain improve on better results. The objective of this work falls in the creation of communication tools with intra-body sensors. These sensors must be able to collect intra-body parameters such as human core temperature. To reach this main objective the construction of a new intra-body sensor for acquisition and monitoring the intra-vaginal temperature is proposed. This novel intra-body sensor provides data collection that is used to studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc. The novel sensor and his communication tools was tested and validated on hospitalized women as well as normal healthy women. Finally a medical team has attested to the accuracy, usability and performance of this novel intrabody sensor

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved