Energy-Efficient Multiple Relay Selection in Cognitive Radio Networks

Cognitive Radios play very important role in military applications due to their capability to adapt intelligently according to the prevailing environmental conditions. Relays form the main communication enablers in infrastructure-less networks. In this paper, relay selection for increasing the energy efficiency of a cognitive radio network is considered. The proposed approach considers the multiple - relay selection scheme with strict outage probability constraints. Energy maximisation is posed as an optimisation problem, the solution to which shows that relay selection under outage constraints is different from the one without such a constraint. It can be observed from the simulations that energy efficiency and outage behaviour follows trade-off relations. Moreover, the original Branch and Bound algorithm has been re-designed for faster convergence. It has also been demonstrated that when strict outage constraints are imposed, the optimal number of relays selected will be more in comparison to the case where there is no outage consideration

The rotation curves of dwarf galaxies: a problem for Cold Dark Matter?

We address the issue of accuracy in recovering density profiles from observations of rotation curves of galaxies. We ``observe'' and analyze our models in much the same way as observers do the real galaxies. We find that the tilted ring model analysis produces an underestimate of the central rotational velocity. In some cases the galaxy halo density profile seems to have a flat core, while in reality it does not. We identify three effects, which explain the systematic biases: (1) inclination (2), small bulge, and (3) bar. The presence of even a small non-rotating bulge component reduces the rotation velocity. In the case of a disk with a bar, the underestimate of the circular velocity is larger due to a combination of non-circular motions and random velocities. Signatures of bars can be difficult to detect in the surface brightness profiles of the model galaxies. The variation of inclination angle and isophote position angle with radius are more reliable indicators of bar presence than the surface brightness profiles. The systematic biases in the central ~ 1 kpc of galaxies are not large. Each effect separately gives typically a few kms error, but the effects add up. In some cases the error in circular velocity was a factor of two, but typically we get about 20 percent. The result is the false inference that the density profile of the halo flattens in the central parts. Our observations of real galaxies show that for a large fraction of galaxies the velocity of gas rotation (as measured by emission lines) is very close to the rotation of stellar component (as measured by absorption lines). This implies that the systematic effects discussed in this paper are also applicable both for the stars and emission-line gas.Comment: ApJ, in press, 30 pages, Latex, 21 .eps figure

Urban ReLeaf: Citizen-powered data ecosystems for inclusive and green urban transitions

Session: Citizen science uptake in official data and decision ecosystems – establishing a new common practice In recent years citizen science has become widely recognised for its potential beyond science, e.g., to provide data to official assessment and accounting systems, helping to close spatial and temporal data gaps, or to provide methods to enhance public participation in the scientific and policy discourse, amongst others. Lighthouse projects across the globe have demonstrated that citizen science data can serve SDG monitoring (Ghana), outweigh official data sources for official air quality reporting (Flanders) or lead to urban re-design of public spaces to reduce noise pollution (Barcelona). At the same time, citizen science practices are debated for their legitimacy, in a narrow sense related to data quality, in a wider sense related to their potential of calling existing accountability systems and power structures into question. This session aims at reflecting current developments by bringing practitioners together to enhance knowledge exchange and to jointly sketch trends and key leverage points towards facilitating the uptake of citizen science data and practice in authoritative data flows and policy makin

Urban ReLeaf – Athens Pilot: Citizen-powered data ecosystems for inclusive and green urban transitions.

Session: Pathways to sustainable development through use cases in the Athens metropolis sessio

Josephson junction array type I-V characteristics of quench-condensed ultra thin films of Bi

In this communication we report studies of d.c current-voltage (I-V) characteristics of ultra thin films of Bi, quench condensed on single crystal sapphire substrates at T = 15K. The hysteretic I-V characteristics are explained using a resistively and capacitively shunted junction (RCSJ) model of Josephson junction arrays. The Josephson coupling energy($E_J$) and the charging energy($E_c$) are calculated for different thickness($d$) values. A low resistance state is found in the low current regime below the critical current, $I_c$. This resistance $R_0$ is found to have a minimum at a particular thickness ($d_c$) value. Reflection High Energy Electron Diffraction (RHEED) studies are done on these films. A distinct appearance of a diffuse ring near $d_c$ is observed in the diffraction images, consistent with the recent STM studies(Ekinci and Valles, PRL {\bf 82}(1999) 1518). These films show an irreversible annealing when temperature is increased. The annealing temperature ($T_a$) also has a maximum at the same thickness. Althoguh the R$_s$ vs T of quench condensed Bi films suggest that the films are uniform, our results indicate that even in thick films, the order parameter is not fully developed over the complete area of the film. These results are discussed qualitatively.Comment: 6 pages, 6 figure

Crowdsourcing EO datasets to improve cloud detection algorithms and land cover change

Involving citizens in science is gaining considerable traction of late. With positive examples (e.g. Geo-Wiki, FotoQuest Austria), a number of projects are exploring the options to engage the public in contributing to scientific research, often by asking participants to collect some data or validate some results. The International Institute for Applied Systems Analysis (IIASA), with extensive experience in crowdsourcing and gamification, has joined Sinergise, Copernicus Masters 2016 winners, to engage the public in an initiative involving ESA’s Sentinel-2 satellite imagery. Sentinel-2 imagery offers high revisit times and sufficient resolution for land change detection applications. Unfortunately, simple (but fast) algorithms often fail due to many false-positives: changes in clouds are perceived as land changes. The ability to discriminate of cloudy pixels is thus crucial for any automatic or semi-automatic solutions that detect land change. A plethora of algorithms to distinguish clouds in Sentinel-2 data are available. However, there is a need for better data on where and when clouds occur to help improve these algorithms. To overcome this current gap in the data, we are engaging the public in this task. Using a number of tools, developed at IIASA, and Sentinel Hub services, which provide fast access to the entire global archive of Sentinel-2 data, the aim is to obtain a large data resource of curated cloud classifications. The resulting dataset will be published as open data and made available through Geopedia platform. The gamified process will start by asking users if there are clouds on a small image (e.g. 8x8 pixels at the highest Sentinel-2 resolution of 10 m/px), which will provide us with a screening process to pinpoint cloudy areas, employing Picture Pile crowdsourcing game from IIASA. The next step will involve a more detailed workflow, as users will get a slightly larger image (e.g. 64x64 pixels) and will then be asked to delineate different types of clouds: opaque clouds (nothing is seen through the clouds), thick clouds (where the surface is still discernible through the clouds), and thin clouds (where the surface is unequivocally covered by a cloud); the rest of the image will be implicitly cloud-free. The resulting data will be made available through the Geopedia portal, both for exploring and downloading. This paper will demonstrate this process and show some results from a crowdsourcing campaign. The approach will also allow us to collect other datasets in a rapid and efficient manner. For example, using a slightly modified configuration, a similar workflow could be used to obtain a manually curated land cover classification data set, which could be used as training data for machine learning algorithms

WHO consultation on Respiratory Syncytial Virus Vaccine Development Report from a World Health Organization Meeting held on 23–24 March 2015

AbstractRespiratory syncytial virus (RSV) is a globally prevalent cause of lower respiratory infection in neonates and infants. Despite its disease burden, a safe and effective RSV vaccine has remained elusive. In recent years, improved understanding of RSV biology and innovations in immunogen design has resulted in the advancement of multiple vaccine candidates into the clinical development pipeline. Given the growing number of vaccines in clinical trials, the rapid pace at which they are being tested, and the likelihood that an RSV vaccine will reach the commercial market in the next 5–10 years, consensus and guidance on clinical development pathways and licensure routes are needed now, before large-scale efficacy trials commence. In pursuit of this aim, the World Health Organization convened the first RSV vaccine consultation in 15 years on the 23rd and 24th of March, 2015 in Geneva, Switzerland. The meeting's primary objective was to provide guidance on clinical endpoints and development pathways for vaccine trials with a focus on considerations of low- and middle-income countries. Meeting participants reached consensus on candidate case definitions for RSV disease, considerations for clinical efficacy endpoints, and the clinical development pathway for active and passive immunization trials in maternal and pediatric populations. The strategic focus of this meeting was on the development of high quality, safe and efficacious RSV preventive interventions for global use and included: (1) maternal/passive immunization to prevent RSV disease in infants less than 6 months; (2) pediatric immunization to prevent RSV disease in infants and young children once protection afforded by maternal immunization wanes

Citizen Science Daten und Praktiken – (Konflikt-)Potentiale für bürger*innenbasierte Datenströme und neue Formen urbaner Entscheidungsfindung

Das Potenzial von Citizen Science ist über die Wissenschaft hinaus bekannt, z.B. in der Bereitstellung von Daten für amtliche Informationssysteme, bei der Schließung räumlicher und zeitlicher Datenlücken oder zur besseren Beteiligung der Öffentlichkeit am wissenschaftlichen und politischen Diskurs. Gleichzeitig wird über die Legitimität von Citizen Science debattiert, im engeren Sinne in Bezug auf Datenqualität, im weiteren Sinne hinsichtlich ihres Potenzials, bestehende Entscheidungssysteme in Frage zu stellen oder Lücken darin aufzuzeigen. In diesem Cabin Talk wird anhand von Real-Life-Szenarien durchgespielt und reflektiert, welche Potentiale bürger*innenbasierte Datenströme in der urbanen Klimawandelanpassung und Grünraumplanung haben, wie diese durch latente Macht- und Zielkonflikte zwischen beteiligten Akteur*innen beeinflusst werden und welche rechtlichen Grundlagen die Situation bestimmen

Planck’s Constant and Equation for Magnetic Field Waves

The classical Planck’s equation E = hν in terms of frequency ν is applicable for all light rays including x-rays and gamma rays. A new Planck equation E = ⓗλ in terms of wavelength λ is found for all magnetic field waves including radio waves. The new Planck constant ⓗ is found, approximately, and a one-to-one correspondence between ν for light rays and λ for magnetic field waves is established. This correspondence provides an equality relation for penetrating capacities of a light ray radiation and a corresponding magnetic ray radiation. This equality relation helps to calculate penetrating capacity of a magnetic field wave from penetrating capacity of a light wave