Ultralow Power Energy Harvesting Body Area Network Design: A Case Study

Citation: Zheng, C. Y., Kuhn, W. B., & Natarajan, B. (2015). Ultralow Power Energy Harvesting Body Area Network Design: A Case Study. International Journal of Distributed Sensor Networks, 11. doi:10.1155/2015/824705This paper presents an energy harvesting wireless sensor network (EHWSN) architecture designed for use within an astronaut's space suit. The contribution of this work spans both physical (PHY) layer energy harvesting transceiver design and low power medium access control (MAC) solutions. The architecture consists of a star topology with two types of transceiver nodes: a powered gateway radio (GR) node and multiple energy harvesting biosensor radio (BSR) nodes. To demonstrate the feasibility of an EHWSN at the PHY layer, a representative BSR node is implemented. The BSR node is powered by a thermal energy harvesting system (TEHS) which exploits the difference between the temperatures of a space suit's cooling garment and the astronaut's body. It is shown that, through appropriate control of the duty cycle in transmission and receiving modes, it is possible to operate with less than 1 mW generated by the TEHS. This requires ultralow duty cycle which complicates MAC layer design because a BSR node must sleep for more than 99.6% of overall operation time. The challenge for MAC layer design is the inability to predict when the BSR node awakens from sleep mode due to unpredictability of the harvested energy. Therefore, a new feasible MAC layer design, GRI-(gateway radio initialized-) MAC, is proposed and analyzed

Oil palm cultivation critically affects sociality in a threatened Malaysian primate

Human-induced habitat alterations globally threaten animal populations, often evoking complex behavioural responses in wildlife. This may be particularly dramatic when negatively affecting social behaviour, which fundamentally determines individual fitness and offspring survival in group-living animals. Here, we provide first evidence for significant behavioural modifications in sociality of southern pig-tailed macaques visiting Malaysian oil palm plantations in search of food despite elevated predation risk. Specifically, we found critical reductions of key positive social interactions but higher rates of aggression in the plantation interior compared to the plantation edge (i.e. plantation areas bordering the forest) and the forest. At the plantation edge, affiliation even increased compared to the forest, while central positions in the macaques' social network structure shifted from high-ranking adult females and immatures to low-ranking individuals. Further, plantations also affected mother-infant relationships, with macaque mothers being more protective in the open plantation environment. We suggest that although primates can temporarily persist in human-altered habitats, their ability to permanently adapt requires the presence of close-by forest and comes with a trade-off in sociality, potentially hampering individual fitness and infant survival. Studies like ours remain critical for understanding species’ adaptability to anthropogenic landscapes, which may ultimately contribute to facilitating their coexistence with humans and preserving biodiversity

An Automated Algorithm to Distinguish and Characterize Solar Flares and Associated Sequential Chromospheric Brightenings

We present a new automated algorithm to identify, track, and characterize small-scale brightening associated with solar eruptive phenomena observed in H{\alpha}. The temporal spatially-localized changes in chromospheric intensities can be separated into two categories: flare ribbons and sequential chromospheric brightenings (SCBs). Within each category of brightening we determine the smallest resolvable locus of pixels, a kernel, and track the temporal evolution of the position and intensity of each kernel. This tracking is accomplished by isolating the eruptive features, identifying kernels, and linking detections between frames into trajectories of kernels. We fully characterize the evolving intensity and morphology of the flare ribbons by observing the tracked flare kernels in aggregate. With the location of SCB and flare kernels identified, they can easily be overlaid on top of complementary data sets to extract Doppler velocities and magnetic field intensities underlying the kernels. This algorithm is adaptable to any dataset to identify and track solar features.Comment: 22 pages, 9 figure

A Novel Approach to High-temperature In-situ Ultrasonic NDE Using Magnetostriction

Online ultrasonic NDE at high-temperature is of much interest to the power, process and automotive industries in view of possible savings in down-time. This paper describes a novel approach to develop ultrasonic transducers capable of high-temperature in-situ operation using the principle of magnetostriction. Preliminary design from previous research by the authors is extended for operation at 1 MHz, and elevated temperatures by using MetGlas s the magnetostrictive core. Ultrasonic signals in pulse-echo mode are experimentally obtained from the ultrasonic transducer thus developed, in simulated high temperature environment of 350 °C for 10 hours. Advantages and challenges for practical deployment of this approach are discussed

Analysis of a global Moreton wave observed on October 28, 2003

We study the well pronounced Moreton wave that occurred in as- sociation with the X17.2 are/CME event of October 28, 2003. This Moreton wave is striking for its global propagation and two separate wave centers, which implies that two waves were launched simultane- ously. The mean velocity of the Moreton wave, tracked within different sectors of propagation direction, lies in the range of v ~ 900-1100 km/s with two sectors showing wave deceleration. The perturbation profile analysis of the wave indicates amplitude growth followed by amplitude weakening and broadening of the perturbation profile, which is con- sistent with a disturbance first driven and then evolving into a freely propagating wave. The EIT wavefront is found to lie on the same kinematical curve as the Moreton wavefronts indicating that both are different signatures of the same physical process. Bipolar coronal dim- mings are observed on the same opposite East-West edges of the active region as the Moreton wave ignition centers. The radio type II source, which is co-spatially located with the first wave front, indicates that the wave was launched from an extended source region (& 60 Mm). These findings suggest that the Moreton wave is initiated by the CME expanding flanks.Comment: accepted to Ap

Efficient management of virtualized information-centric networks

The Internet has rapidly evolved from a network, connecting a couple of dozens of computers, to a network containing billions of devices. Furthermore, the current Internet is mostly used to deliver complex services with increasingly stringent Quality of Service (QoS) requirements. However, the underlying network model has remained the same, making the Internet not well suited to optimally support the current user trends and services. Currently, a lot of effort is being made in the area of network virtualization and Information-Centric Networking (ICN) to support the evolution towards the QoS constraint distribution of large amounts of information. Even though both directions offer a lot of opportunities, multiple important challenges have to be faced when managing the placement of content inside the network and guaranteeing delivery efficiency. These challenges are further increased when a combination of both trends is considered. This paper gives an overview of these challenges and how this PhD will deal with the mutual influences of network virtualization and ICN in an efficient way

Signatures of the disk-jet coupling in the Broad-line Radio Quasar 4C+74.26

Here we explore the disk-jet connection in the broad-line radio quasar 4C+74.26, utilizing the results of the multiwavelength monitoring of the source. The target is unique in that its radiative output at radio wavelengths is dominated by a moderately-beamed nuclear jet, at optical frequencies by the accretion disk, and in the hard X-ray range by the disk corona. Our analysis reveals a correlation (local and global significance of 96\% and 98\%, respectively) between the optical and radio bands, with the disk lagging behind the jet by $250 \pm 42$ days. We discuss the possible explanation for this, speculating that the observed disk and the jet flux changes are generated by magnetic fluctuations originating within the innermost parts of a truncated disk, and that the lag is related to a delayed radiative response of the disk when compared with the propagation timescale of magnetic perturbations along relativistic outflow. This scenario is supported by the re-analysis of the NuSTAR data, modelled in terms of a relativistic reflection from the disk illuminated by the coronal emission, which returns the inner disk radius $R_{\rm in}/R_{\rm ISCO} =35^{+40}_{-16}$. We discuss the global energetics in the system, arguing that while the accretion proceeds at the Eddington rate, with the accretion-related bolometric luminosity $L_{\rm bol} \sim 9 \times 10^{46}$ erg s$^{-1}$ $\sim 0.2 L_{\rm Edd}$, the jet total kinetic energy $L_\textrm{j} \sim 4 \times 10^{44}$ erg s$^{-1}$, inferred from the dynamical modelling of the giant radio lobes in the source, constitutes only a small fraction of the available accretion power.Comment: 9 pages and 6 figures, ApJ accepte