Towards a fuzzy-based multi-classifier selection module for activity recognition applications

Performing activity recognition using the information provided by the different sensors embedded in a smartphone face limitations due to the capabilities of those devices when the computations are carried out in the terminal. In this work a fuzzy inference module is implemented in order to decide which classifier is the most appropriate to be used at a specific moment regarding the application requirements and the device context characterized by its battery level, available memory and CPU load. The set of classifiers that is considered is composed of Decision Tables and Trees that have been trained using different number of sensors and features. In addition, some classifiers perform activity recognition regardless of the on-body device position and others rely on the previous recognition of that position to use a classifier that is trained with measurements gathered with the mobile placed on that specific position. The modules implemented show that an evaluation of the classifiers allows sorting them so the fuzzy inference module can choose periodically the one that best suits the device context and application requirements

Congestion and medium access control in 6LoWPAN WSN

In computer networks, congestion is a condition in which one or more egressinterfaces are offered more packets than are forwarded at any given instant [1]. In wireless sensor networks, congestion can cause a number of problems including packet loss, lower throughput and poor energy efficiency. These problems can potentially result in a reduced deployment lifetime and underperforming applications. Moreover, idle radio listening is a major source of energy consumption therefore low-power wireless devices must keep their radio transceivers off to maximise their battery lifetime. In order to minimise energy consumption and thus maximise the lifetime of wireless sensor networks, the research community has made significant efforts towards power saving medium access control protocols with Radio Duty Cycling. However, careful study of previous work reveals that radio duty cycle schemes are often neglected during the design and evaluation of congestion control algorithms. This thesis argues that the presence (or lack) of radio duty cycle can drastically influence the performance of congestion control mechanisms. To investigate if previous findings regarding congestion control are still applicable in IPv6 over low power wireless personal area and duty cycling networks; some of the most commonly used congestion detection algorithms are evaluated through simulations. The research aims to develop duty cycle aware congestion control schemes for IPv6 over low power wireless personal area networks. The proposed schemes must be able to maximise the networks goodput, while minimising packet loss, energy consumption and packet delay. Two congestion control schemes, namely DCCC6 (Duty Cycle-Aware Congestion Control for 6LoWPAN Networks) and CADC (Congestion Aware Duty Cycle MAC) are proposed to realise this claim. DCCC6 performs congestion detection based on a dynamic buffer. When congestion occurs, parent nodes will inform the nodes contributing to congestion and rates will be readjusted based on a new rate adaptation scheme aiming for local fairness. The child notification procedure is decided by DCCC6 and will be different when the network is duty cycling. When the network is duty cycling the child notification will be made through unicast frames. On the contrary broadcast frames will be used for congestion notification when the network is not duty cycling. Simulation and test-bed experiments have shown that DCCC6 achieved higher goodput and lower packet loss than previous works. Moreover, simulations show that DCCC6 maintained low energy consumption, with average delay times while it achieved a high degree of fairness. CADC, uses a new mechanism for duty cycle adaptation that reacts quickly to changing traffic loads and patterns. CADC is the first dynamic duty cycle pro- tocol implemented in Contiki Operating system (OS) as well as one of the first schemes designed based on the arbitrary traffic characteristics of IPv6 wireless sensor networks. Furthermore, CADC is designed as a stand alone medium access control scheme and thus it can easily be transfered to any wireless sensor network architecture. Additionally, CADC does not require any time synchronisation algorithms to operate at the nodes and does not use any additional packets for the exchange of information between the nodes (For example no overhead). In this research, 10000 simulation experiments and 700 test-bed experiments have been conducted for the evaluation of CADC. These experiments demonstrate that CADC can successfully adapt its cycle based on traffic patterns in every traffic scenario. Moreover, CADC consistently achieved the lowest energy consumption, very low packet delay times and packet loss, while its goodput performance was better than other dynamic duty cycle protocols and similar to the highest goodput observed among static duty cycle configurations

Internet of Things Applications - From Research and Innovation to Market Deployment

The book aims to provide a broad overview of various topics of Internet of Things from the research, innovation and development priorities to enabling technologies, nanoelectronics, cyber physical systems, architecture, interoperability and industrial applications. It is intended to be a standalone book in a series that covers the Internet of Things activities of the IERC – Internet of Things European Research Cluster from technology to international cooperation and the global "state of play".The book builds on the ideas put forward by the European research Cluster on the Internet of Things Strategic Research Agenda and presents global views and state of the art results on the challenges facing the research, development and deployment of IoT at the global level. Internet of Things is creating a revolutionary new paradigm, with opportunities in every industry from Health Care, Pharmaceuticals, Food and Beverage, Agriculture, Computer, Electronics Telecommunications, Automotive, Aeronautics, Transportation Energy and Retail to apply the massive potential of the IoT to achieving real-world solutions. The beneficiaries will include as well semiconductor companies, device and product companies, infrastructure software companies, application software companies, consulting companies, telecommunication and cloud service providers. IoT will create new revenues annually for these stakeholders, and potentially create substantial market share shakeups due to increased technology competition. The IoT will fuel technology innovation by creating the means for machines to communicate many different types of information with one another while contributing in the increased value of information created by the number of interconnections among things and the transformation of the processed information into knowledge shared into the Internet of Everything. The success of IoT depends strongly on enabling technology development, market acceptance and standardization, which provides interoperability, compatibility, reliability, and effective operations on a global scale. The connected devices are part of ecosystems connecting people, processes, data, and things which are communicating in the cloud using the increased storage and computing power and pushing for standardization of communication and metadata. In this context security, privacy, safety, trust have to be address by the product manufacturers through the life cycle of their products from design to the support processes. The IoT developments address the whole IoT spectrum - from devices at the edge to cloud and datacentres on the backend and everything in between, through ecosystems are created by industry, research and application stakeholders that enable real-world use cases to accelerate the Internet of Things and establish open interoperability standards and common architectures for IoT solutions. Enabling technologies such as nanoelectronics, sensors/actuators, cyber-physical systems, intelligent device management, smart gateways, telematics, smart network infrastructure, cloud computing and software technologies will create new products, new services, new interfaces by creating smart environments and smart spaces with applications ranging from Smart Cities, smart transport, buildings, energy, grid, to smart health and life. Technical topics discussed in the book include: • Introduction• Internet of Things Strategic Research and Innovation Agenda• Internet of Things in the industrial context: Time for deployment.• Integration of heterogeneous smart objects, applications and services• Evolution from device to semantic and business interoperability• Software define and virtualization of network resources• Innovation through interoperability and standardisation when everything is connected anytime at anyplace• Dynamic context-aware scalable and trust-based IoT Security, Privacy framework• Federated Cloud service management and the Internet of Things• Internet of Things Application

Exposure assessment for mobile phone use and radiofrequency electromagnetic fields and the application in a Swiss cohort study

Background Mobile phones and other wireless communication devices emitting radiofrequency electromagnetic fields (RF-EMF) are nowadays omnipresent and adolescents are among the heaviest users. This results in ubiquitous RF-EMF exposure, though little is known about the levels of this exposure, especially in adolescents. Exposure to RF-EMF can be divided into two parts, the exposure from the use of wireless communication devices (near-field) and the exposure from environmental sources (far-field). In previous studies, the near-field exposure was quantified using the amount of device use only. The RF-EMF exposure resulting from the device use, however, is not only dependent on the duration of use, but additionally for instance on the mode of use and the network used for mobile phone calls. The far-field exposure from fixed site transmitters such as broadcast transmitters for radio and television (TV) and mobile phone base stations was modelled using geospatial propagation models or measured using portable RF-EMF measurement devices. But this part of the exposure also depends on the duration a person is exposed to modelled or measured exposure levels. Therefore a dosimetric approach is needed that allows taking into account these additional aspects of exposure and to combine the near-field and the far-field exposure to one exposure surrogate. Since the mobile phone use increased in the last decade, there is concern that this use may have a negative impact on adolescents. To date, epidemiological studies in adolescents are scarce. In addition, the ones existing used self-reported device use that is known to be inaccurate and the amount of device use was used as proxy for the RF-EMF exposure not taking into account other RF-EMF sources. Furthermore, most of these studies were of cross-sectional design not allowing to draw conclusions about causal relationships between mobile phone use and health, behaviour and cognitive function of adolescents. To overcome these limitations, the HERMES (Health Effects Related to Mobile phonE use in adolescentS) study was conducted. Objectives The objective of the HERMES study was to prospectively investigate whether mobile phone use and the use of other wireless communication devices or RF-EMF exposure have an impact on the health and the behaviour of adolescents and if cognitive function of adolescents is affected by these exposures. The objectives of this thesis were to improve the exposure assessment for mobile phone use and RF-EMF exposure and to investigate its relations to behavioural problems and concentration capacity of adolescents. Methods The HERMES study was a prospective cohort study with a one year follow-up period. It was conducted in Central Switzerland in adolescents attending the 7th school grade. The investigation took place in the schools during school time and consisted of filling in a paper and pencil questionnaire and performing computerized cognitive tests. In addition, a questionnaire for the parents was distributed that was directly sent back to the study managers. Additionally to the amount of mobile phone and other device use, problematic aspects of mobile phone use such as loss of control, withdrawal, negative life consequences and craving were asked in the questionnaire. In a subgroup of the study participants, personal RF-EMF measurements were conducted. The participating adolescents carried a portable measurement device for three consecutive days and filled in a time-activity diary to record their locations during the measurement period. The questionnaire data and the personal RF-EMF measurements together with geospatial propagation modelling for the exposure originating from fixed site transmitters at home and in the schools as well as operator-recorded mobile phone use data for a subgroup of the study participants were used to develop an RF-EMF exposure surrogate combining the exposure from the use of wireless communication devices and environmental sources. This exposure surrogate was then used to conduct cross-sectional and longitudinal analyses of RF-EMF exposure and behaviour and concentration capacity of adolescents. Results 439 adolescents participated in the HERMES study (participation rate of 36.8%) with a follow-up rate of 96.8%. Operator records were available for 234 adolescents and personal RF-EMF measurements were available for a subgroup of 90 adolescents. We found that problematic mobile phone use in adolescents was related to behavioural problems such as hyperactivity, conduct problems, emotional symptoms and antisocial behaviour and impaired health related quality of life (HRQOL) facets such as home life and school environment. The main contributor to the measured personal RF-EMF exposure was the mobile internet use on the mobile phone. For the adolescents not using mobile internet, mobile phone base stations contributed most to their exposure. Having wireless internet (WLAN) at home and attending a school with WLAN had very little impact on the average measured WLAN exposure. According to the developed RF-EMF exposure surrogate combining near-field and far-field exposure, the exposure from environmental sources such as fixed site transmitters, cordless phone and WLAN base stations and mobile phones in the surroundings plays a minor role compared to the exposure from the use of wireless communication devices (mobile phones, cordless phones, computers, laptops and tablets connected to WLAN). The near-field dose accounted for 98.4% of the brain dose and 94.0% of the whole body dose. In applying the developed RF-EMF dose surrogate in combination with use measures derived from self-reported device use and operator-recorded mobile phone use, the relations to behavioural problems and the concentration capacity of adolescents were investigated. No systematic pattern in relation to RF-EMF exposure was observed indicating no causal relationship between RF-EMF exposure and behavioural problems and concentration capacity of adolescents. Conclusions Environmental sources play a minor role for the RF-EMF exposure of adolescents compared to the use of wireless devices. Having WLAN at home and attending a school with WLAN have very little impact on the average measured WLAN exposure. The use of mobile internet results in higher measured exposure from mobile phones. Therefore, precautionary measures to reduce the exposure to RF-EMF should focus on the use of wireless devices. The behaviour and the concentration capacity of adolescents were not affected by RF-EMF exposure. In contrary, behavioural problems and impaired HRQOL were associated with problematic aspects of mobile phone use. Therefore, problematic mobile phone use should be considered if dealing with adolescents showing behavioural problems or impaired mental health. The HERMES study was the first study applying a comprehensive exposure assessment including operator-recorded mobile phone use and cumulative RF-EMF dose calculations. The study provided new insights into the mobile phone use of Swiss adolescents and its impact on health, behaviour and cognitive function using a longitudinal approach allowing to draw conclusions about causal relationships. The applied methods can be used in future epidemiological studies on RF-EMF exposure and its influence on humans