43 research outputs found
Surface MIMO: Using Conductive Surfaces For MIMO Between Small Devices
As connected devices continue to decrease in size, we explore the idea of
leveraging everyday surfaces such as tabletops and walls to augment the
wireless capabilities of devices. Specifically, we introduce Surface MIMO, a
technique that enables MIMO communication between small devices via surfaces
coated with conductive paint or covered with conductive cloth. These surfaces
act as an additional spatial path that enables MIMO capabilities without
increasing the physical size of the devices themselves. We provide an extensive
characterization of these surfaces that reveal their effect on the propagation
of EM waves. Our evaluation shows that we can enable additional spatial streams
using the conductive surface and achieve average throughput gains of 2.6-3x for
small devices. Finally, we also leverage the wideband characteristics of these
conductive surfaces to demonstrate the first Gbps surface communication system
that can directly transfer bits through the surface at up to 1.3 Gbps.Comment: MobiCom '1
An ancient extrasolar system with five sub-Earth-size planets
The chemical composition of stars hosting small exoplanets (with radii less
than four Earth radii) appears to be more diverse than that of gas-giant hosts,
which tend to be metal-rich. This implies that small, including Earth-size,
planets may have readily formed at earlier epochs in the Universe's history
when metals were more scarce. We report Kepler spacecraft observations of
Kepler-444, a metal-poor Sun-like star from the old population of the Galactic
thick disk and the host to a compact system of five transiting planets with
sizes between those of Mercury and Venus. We validate this system as a true
five-planet system orbiting the target star and provide a detailed
characterization of its planetary and orbital parameters based on an analysis
of the transit photometry. Kepler-444 is the densest star with detected
solar-like oscillations. We use asteroseismology to directly measure a precise
age of 11.2+/-1.0 Gyr for the host star, indicating that Kepler-444 formed when
the Universe was less than 20% of its current age and making it the oldest
known system of terrestrial-size planets. We thus show that Earth-size planets
have formed throughout most of the Universe's 13.8-billion-year history,
leaving open the possibility for the existence of ancient life in the Galaxy.
The age of Kepler-444 not only suggests that thick-disk stars were among the
hosts to the first Galactic planets, but may also help to pinpoint the
beginning of the era of planet formation.Comment: Accepted for publication in ApJ; 42 pages, 10 figures, 4 table
KOI-3158: The oldest known system of terrestrial-size planets
The first discoveries of exoplanets around Sun-like stars have fueled efforts
to find ever smaller worlds evocative of Earth and other terrestrial planets in
the Solar System. While gas-giant planets appear to form preferentially around
metal-rich stars, small planets (with radii less than four Earth radii) can
form under a wide range of metallicities. This implies that small, including
Earth-size, planets may have readily formed at earlier epochs in the Universe's
history when metals were far less abundant. We report Kepler spacecraft
observations of KOI-3158, a metal-poor Sun-like star from the old population of
the Galactic thick disk, which hosts five planets with sizes between Mercury
and Venus. We used asteroseismology to directly measure a precise age of
11.2+/-1.0 Gyr for the host star, indicating that KOI-3158 formed when the
Universe was less than 20% of its current age and making it the oldest known
system of terrestrial-size planets. We thus show that Earth-size planets have
formed throughout most of the Universe's 13.8-billion-year history, providing
scope for the existence of ancient life in the Galaxy.Comment: Submitted to EPJ Web of Conferences, to appear in the Proceedings of
the 3rd CoRoT Symposium, Kepler KASC7 joint meeting; 4 pages, 1 figur
Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)
\We present the sixth catalog of Kepler candidate planets based on nearly 4
years of high precision photometry. This catalog builds on the legacy of
previous catalogs released by the Kepler project and includes 1493 new Kepler
Objects of Interest (KOIs) of which 554 are planet candidates, and 131 of these
candidates have best fit radii <1.5 R_earth. This brings the total number of
KOIs and planet candidates to 7305 and 4173 respectively. We suspect that many
of these new candidates at the low signal-to-noise limit may be false alarms
created by instrumental noise, and discuss our efforts to identify such
objects. We re-evaluate all previously published KOIs with orbital periods of
>50 days to provide a consistently vetted sample that can be used to improve
planet occurrence rate calculations. We discuss the performance of our planet
detection algorithms, and the consistency of our vetting products. The full
catalog is publicly available at the NASA Exoplanet Archive.Comment: 18 pages, to be published in the Astrophysical Journal Supplement
Serie
Constructing a climate change logic: An institutional perspective on the "tragedy of the commons"
Despite increasing interest in transnational fields, transnational commons have received little attention. In contrast to economic models of commons, which argue that commons occur naturally and are prone to collective inaction and tragedy, we introduce a social constructionist account of commons. Specifically, we show that actor-level frame changes can eventually lead to the emergence of an overarching, hybrid "commons logic" at the field level. These frame shifts enable actors with different logics to reach a working consensus and avoid "tragedies of the commons." Using a longitudinal analysis of key actors' logics and frames, we tracked the evolution of the global climate change field over 40 years. We bracketed time periods demarcated by key field-configuring events, documented the different frame shifts in each time period, and identified five mechanisms (collective theorizing, issue linkage, active learning, legitimacy seeking, and catalytic amplification) that underpin how and why actors changed their frames at various points in time-enabling them to move toward greater consensus around a transnational commons logic. In conclusion, the emergence of a commons logic in a transnational field is a nonlinear process and involves satisfying three conditions: (1) key actors view their fates as being interconnected with respect to a problem issue, (2) these actors perceive their own behavior as contributing to the problem, and (3) they take collective action to address the problem. Our findings provide insights for multinational companies, nation-states, nongovernmental organizations, and other stakeholders in both conventional and unconventional commons
KOI-3158: The oldest known system of terrestrial-size planets
The first discoveries of exoplanets around Sun-like stars have fueled efforts to find ever smaller worlds evocative of Earth and other terrestrial planets in the Solar System. While gas-giant planets appear to form preferentially around metal-rich stars, small planets (with radii less than four Earth radii) can form under a wide range of metallicities. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were far less abundant. We report Kepler spacecraft observations of KOI-3158, a metal-poor Sun-like star from the old population of the Galactic thick disk, which hosts five planets with sizes between Mercury and Venus. We used asteroseismology to directly measure a precise age of 11.2 ± 1.0 Gyr for the host star, indicating that KOI-3158 formed when the Universe was less than 20 % of its current age and making it the oldest known system of terrestrial-size planets. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, providing scope for the existence of ancient life in the Galaxy
A gender approach to understanding the differentiated impact of barriers to adaptation: responses to climate change in rural Ethiopia
Energy-efficient cluster-based security mechanism for intra-WBAN and inter-WBAN communications for healthcare applications
TR-UH-EDM-0603 USING DEVICE FEDERATIONS TO ENHANCE THE CREATIVE PROCESS IN A DISTRIBUTED INTERACTION ENVIRONMENT
Using device federations to enhance the creative process in a distributed interaction environmen
AppA
Continuous, remote monitoring of patients using wearable sensors can facilitate early detection of many conditions and can help to manage the growing healthcare crisis worldwide. A remote patient monitoring application consists of many emerging services such as wireless wearable sensor configuration, patient registration and authentication, collaborative consultation of doctors, storage and maintenance of electronic health record. The provision of these services requires the development and maintenance of a remote healthcare monitoring application (HMA) that includes a body area wireless sensor network (BASWN) and Health Applications (HA) to detect specific health issues. In addition, the deployment of HMAs for different hospitals is not easily scalable owing to the heterogeneous nature of hardware and software involved. Cloud computing overcomes this aspect by allowing simple and easy maintenance of ICT infrastructure. In this work, we report a realtime- like cloud based architecture known as Assistive Patient monitoring cloud Platform for Active healthcare applications (AppA) using a delegate pattern. The built AppA is highly scalable and capable of spawning new instances based on the monitoring requirements from the health care providers, and is aligned with scalable economic models