Novel wireless modulation technique based on noise

In this paper, a new RF modulation technique is presented. Instead of using sinusoidal carriers as information bearer, pure noise is applied. This allows very simple radio architectures to be used. Spread-spectrum based technology is applied to modulate the noise bearer. Since the transmission bandwidth of the noise bearer can be made very wide, up to ultra-wideband regions, extremely large processing gains can be obtained. This will provide robustness in interference-prone environments. To avoid the local regeneration of the noise reference at the receiver, the Transmit-Reference (TR) concept is applied. In this concept, both the reference noise signal and the modulated noise signal are transmitted, together forming\ud the bearer. The reference and modulated signals are separated by applying a time offset. By applying different delay times for different channels (users) a new multiple access scheme results based on delay: Delay Division Multiple Access (DDMA). A theoretical analysis is given for the link performance of a single-user and a multi-user system. A testbed has been built to demonstrate the concept. The demonstrator operates in a 50 MHz bandwidth centered at 2.4 GHz. Processing gains ranging from 10¿30 dB have been tested. The testbed confirms the basic behavior as predicted by the theory

EEG connectivity in infants at risk for autism spectrum disorder

Autism Spectrum Disorder (ASD) is characterized by social and communication difficulties, and restricted and repetitive behaviours, and is typically diagnosed during toddlerhood. Electroencephalographic (EEG) connectivity during infancy may predict later diagnostic outcome, and dimensional traits, although results vary with differences in methods. The aim of this thesis is to examine how infant EEG connectivity relates to familial risk, and later categorical and dimensional outcomes of ASD. A previous study found alpha band hyperconnectivity in 14-month-old infants who developed ASD compared to infants who did not develop ASD at 36 months. Chapter 3 shows that methods used in this previous study indeed provide reliable results. Chapter 4 describes the replication study using identical methods to the previous study. Although the difference between groups was not replicated, the association between alpha connectivity and restricted and repetitive behaviours during toddlerhood was replicated. Chapter 5 tested the hypothesis that social and communication difficulties relate to theta connectivity in response to social and non-social stimuli. Theta connectivity was increased during social compared to non-social stimuli. Network topologies differed between groups with high and low familial risk, but not between categorical outcome groups. Theta connectivity was not associated with dimensional traits at toddlerhood. Chapter 6 showed that graph organisation was not related to familial risk, or diagnostic or dimensional outcomes at toddlerhood. Finally, Chapter 7 combined measures from previous chapters and examined how these relate to dimensional outcomes at childhood. Graph organisation at infancy showed a stronger association with dimensional outcomes at childhood than other connectivity measures. Overall, the results in this thesis illustrate the variability in developmental trajectories in ASD, while emphasizing the complexity of the disorder and use of a dimensional approach to ASD. Chapter 8 further discusses contributions and implications for research of EEG connectivity as early predictive marker for ASD

Dealing with the loss of the village supermarket:The perceived effects two years after closure

In 2015, the local supermarket of the depopulating village of Ulrum closed its doors. After a first survey around the closure, a second survey was conducted two years later, to investigate changes in the different meanings of the local supermarket and the perceived effects of its closure over time. The results show that respondents state that the liveability and status of the village have decreased because of the loss of the supermarket. This strongly relates to the symbolic and village level meanings of the supermarket: A village ‘needs’ a supermarket for the villages’ status and as a place to do groceries, and people feel that a village without a supermarket is a village without a heart. The article concludes by alleging that the symbolic meaning of facilities plays an important role in explaining the perceived effects of the loss of the local supermarket

Destination Branding by Residents:The Role of Perceived Responsibility in Positive and Negative Word-of-Mouth

The importance of residents’ communication about their home region as tourist destination is increasingly acknowledged in the place branding process. However, the extent to which residents feel responsible for communicating Destination Images (DIs), and how these attributions affect word-of-mouth (WOM) behavior has remained unclear. This paper addresses this topic by reporting a quantitative study (N = 913) among residents of the Dutch province of Fryslân. The results show that responsibility attributions for communicating positive regional images predict, next to Place Attachment and DI, positive and negative WOM behavior (pWOM and nWOM). Particularly attributing responsibility to citizens themselves is a significant predictor of pWOM and nWOM. Further, findings point to the role of age in variation in responsibility attributions and to previous holiday experience as predictor of nWOM. The implications for citizen engagement in destination branding and regional tourism management are discussed

Experiencing place-change:A shared sense of loss after closure of village facilities

Rural communities often display strong emotions in response to closures of facilities and services. Research into explaining community responses hardly pays attention to the socio-psychological process of 'loss' of such local facilities, which occurs when place bonds are disrupted. This paper explores how a rural community makes sense of place-change by examining how residents interpret, evaluate and cope with local facility-decline. Three focus group discussions were conducted in Tzummarum, a village in the Netherlands, just after the closure of a local sports hall was announced. A theoretical framework for community coping-responses is used to interpret the empirical results. We find that while the closure of local facilities can result in a disruption of individual place bonds, there is a discernible shared sense of loss based on the social and symbolical meaning that certain facilities have for the village community. This sense of loss can help explain collective coping responses. However, this study found that collective action is only considered for local facilities that foster a sense of community, provided there is enough collective efficacy

Who is afraid of population decline? The Struggle of Keeping Rural Depopulation on the Dutch Agenda

The Netherlands is a small, highly urbanised and densely populated country. The distances are short and levels of welfare high. Throughout the 80s and 90s, people were generally satisfied with service levels in rural areas and experienced the rural areas’ quality of life as high. Around 2006, however, the population started to decline in several rural regions. The government responded with the development of two national Action Plans for Population Decline. This paper analyses the national action plans, their content and implementation. It looks into the problem definition and assignment of responsibility, their success in addressing population decline problems, and in keeping depopulation on the political agenda. The paper concludes with some reflections on what we can learn about population decline and related policies based on the experiences in a highly urbanised country like the Netherlands

Physical and Social Engineering in the Dutch Polders:The Case of the Noordoostpolder

This chapter provides an overview of the Zuiderzee project and describes the design and development of the Noordoostpolder. It focuses on the design and development of the Noordoostpolder. Planning projects such as the Zuiderzee project fitted very well into the international Zeitgeist of the interwar period. The reclamation of the Zuiderzee became an object of national pride, attractive to the whole nation and a useful symbol of the Dutch national identity. In the 1960s and 1970s, following sociocultural changes in Dutch society, the selection procedures were criticised more strongly and, in the polders of Oostelijk Flevoland and Zuidelijk Flevoland, they were applied much less strictly. The plans for and implementation of the partial reclamation of the Zuiderzee coincided with the development of the social sciences in the Netherlands. The physical and social planning of the Noordoostpolder reached new heights after 1945. Engineers, architects, spatial planners and social scientists became involved in the development of this polder

An Adaptive Fault-Tolerant Communication Scheme for Body Sensor Networks

A high degree of reliability for critical data transmission is required in body sensor networks (BSNs). However, BSNs are usually vulnerable to channel impairments due to body fading effect and RF interference, which may potentially cause data transmission to be unreliable. In this paper, an adaptive and flexible fault-tolerant communication scheme for BSNs, namely AFTCS, is proposed. AFTCS adopts a channel bandwidth reservation strategy to provide reliable data transmission when channel impairments occur. In order to fulfill the reliability requirements of critical sensors, fault-tolerant priority and queue are employed to adaptively adjust the channel bandwidth allocation. Simulation results show that AFTCS can alleviate the effect of channel impairments, while yielding lower packet loss rate and latency for critical sensors at runtime.Comment: 10 figures, 19 page

Dynamic Streaming Currents From Seismic Point Sources In Homogeneous Poroelastic Media

In a porous medium saturated with a fluid electrolyte, mechanical and electromagnetic disturbances are coupled. The coupling is electrokinetic in nature since it is due to an excess of electrolyte ions that exist in an electric double layer near the grain surfaces within the material. Mechanically-induced streaming currents generated by point sources in homogeneous, isotropic porous media are presented. The electrically-induced streaming current is shown to be second-order in the electrokinetic coupling coefficient and can be neglected. This decouples the mechanical behavior from the electromagnetic behavior with respect to the induced fluxes and simplifies the analysis of the relative fluid flow and dynamic streaming current. We used Biot theory to calculate the amount of induced relative flow by the solution to Green's function. The transport coefficients-conductivity, dynamic permeability, and the electrokinetic coupling coefficient-and their sensitivity with respect to porosity, dc permeability, and frequency changes are evaluated. Conductivity decreases with increasing dc permeability. It has a k[subscript 0][superscript -1/2] dependence when grain surface conductances are more important than the bulk fluid phase conductivity. Stationary phase relative flow and streaming current solutions are calculated for an explosive and vertical point source acting on the bulk and a volume injection source acting on the fluid. The streaming currents are induced both by P and S waves. The streaming current decreases with increasing fluid conductivity. This is consistent with the decrease of the diffuse double layer thickness and ζ-potential. The porosity effect on the streaming current induced by S waves is different from the currents induced by the P waves. The porosity affects the bulk moduli of the solid. Its effect, combined with the frame bulk modulus and compressibility of the saturating fluid, determines the streaming current amplitude induced by a P wave versus porosity. The increase in streaming current amplitude induced by S waves with increasing porosity is due to the decrease of the shear frame modulus with increasing porosity. The streaming current behavior with respect to dc permeability is found to differ for sources applied to the elastic frame and volume injection sources.United States. Dept. of Energy (Grant DE-FG0293ER14322)Massachusetts Institute of Technology. Borehole Acoustics and Logging Consortiu