17 research outputs found
Haematoma caused by bone marrow aspiration and trephine biopsy
We report a case of a bone marrow aspiration and trephine biopsy (BMATB) associated haematoma in an 85-years old male without any predisposing risk factors. Six days after BMATB, he suffered from a massive thigh and buttock haematoma and a fall in haematocrit. It is important to know that BMATB can have complications aiding early recognition and therapy
Auto-configuration of 802.11n WLANs
Channel Bonding (CB) combines two adjacent frequency bands to form a new, wider band to facilitate high data rate transmissions in MIMO-based 802.11n networks. However, the use of a wider band with CB can exacerbate interference effects. Furthermore, CB does not always provide benefits in interference-free settings, and can even degrade performance in some cases. We conduct an in-depth, experimental study to understand the implications of CB. Based on this study we design an auto-configuration framework, ACORN, for enterprise 802.11n WLANs. ACORN integrates the functions of user association and channel allocation, since our study reveals that they are tightly coupled when CB is used. We show that the channel allocation problem with the constraints of CB is NP-complete. Thus, ACORN uses an algorithm that provides a worst case approximation ratio of [EQUATION] with • being the maximum node degree in the network. We implement ACORN on our 802.11n testbed. Our experiments show that ACORN (i) outperforms previous approaches that are agnostic to CB constraints; it provides per-AP throughput gains from 1.5x to 6x and (ii) in practice, its channel allocation module achieves an approximation ratio much better than [EQUATION]. © 2010 ACM
ACORN: An auto-configuration framework for 802.11n WLANs
The wide channels feature combines two adjacent channels to form a new, wider channel to facilitate high-data-rate transmissions in multiple-input- multiple-output (MIMO)-based IEEE 802.11n networks. Using a wider channel can exacerbate interference effects. Furthermore, contrary to what has been reported by prior studies, we find that wide channels do not always provide benefits in isolation (i.e., one link without interference) and can even degrade performance. We conduct an in-depth, experimental study to understand the implications of wide channels on throughput performance. Based on our measurements, we design an auto-configuration framework called ACORN for enterprise 802.11n WLANs. ACORN integrates the functions of user association and channel allocation since our study reveals that they are tightly coupled when wide channels are used. We show that the channel allocation problem with the constraints of wide channels is NP-complete. Thus, ACORN uses an algorithm that provides a worst-case approximation ratio of , with being the maximum node degree in the network. We implement ACORN on our 802.11n testbed. Our evaluations show that ACORN: 1) outperforms previous approaches that are agnostic to wide channels constraints; it provides per-AP throughput gains ranging from 1.5 to 6; and 2) in practice, its channel allocation module achieves an approximation ratio much better than the theoretically predicted . © 1993-2012 IEEE
Recognizing Physical Activity of Older People from Wearable Sensors and Inconsistent Data
The physiological monitoring of older people using wearable sensors has shown great potential in improving their quality of life and preventing undesired events related to their health status. Nevertheless, creating robust predictive models from data collected unobtrusively in home environments can be challenging, especially for vulnerable ageing population. Under that premise, we propose an activity recognition scheme for older people exploiting feature extraction and machine learning, along with heuristic computational solutions to address the challenges due to inconsistent measurements in non-standardized environments. In addition, we compare the customized pipeline with deep learning architectures, such as convolutional neural networks, applied to raw sensor data without any pre- or post-processing adjustments. The results demonstrate that the generalizable deep architectures can compensate for inconsistencies during data acquisition providing a valuable alternative
DISARM early warning system for wildfires in the Eastern Mediterranean
This paper discusses the main achievements of DISARM (Drought and fIre ObServatory and eArly waRning system) project, which developed an early warning system for wildfires in the Eastern Mediterranean. The four pillars of this system include (i) forecasting wildfire danger, (ii) detecting wildfires with remote sensing techniques, (iii) forecasting wildfire spread with a coupled weather-fire modeling system, and (iv) assessing the wildfire risk in the frame of climate change. Special emphasis is given to the innovative and replicable parts of the system. It is shown that for the effective use of fire weather forecasting in different geographical areas and in order to account for the local climate conditions, a proper adjustment of the wildfire danger classification is necessary. Additionally, the consideration of vegetation dryness may provide better estimates of wildfire danger. Our study also highlights some deficiencies of both EUMETSAT (Exploitation of Meteorological Satellites) and LSA-SAF (Satellite Application Facility on Land Surface Analysis) algorithms in their skill to detect wildfires over islands and near the coastline. To tackle this issue, a relevant modification is proposed. Furthermore, it is shown that IRIS, the coupled atmosphere-fire modeling system developed in the frame of DISARM, has proven to be a valuable supporting tool in fire suppression actions. Finally, assessment of the wildfire danger in the future climate provides the necessary context for the development of regional adaptation strategies to climate change. © 2020 by the authors
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The Polarimetric and Helioseismic Imager on Solar Orbiter
This paper describes the Polarimetric and Helioseismic Imager on the Solar
Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument
to observe the Sun from outside the Sun-Earth line. It is the key instrument
meant to address the top-level science question: How does the solar dynamo work
and drive connections between the Sun and the heliosphere? SO/PHI will also
play an important role in answering the other top-level science questions of
Solar Orbiter, as well as hosting the potential of a rich return in further
science.
SO/PHI measures the Zeeman effect and the Doppler shift in the FeI 617.3nm
spectral line. To this end, the instrument carries out narrow-band imaging
spectro-polarimetry using a tunable LiNbO_3 Fabry-Perot etalon, while the
polarisation modulation is done with liquid crystal variable retarders (LCVRs).
The line and the nearby continuum are sampled at six wavelength points and the
data are recorded by a 2kx2k CMOS detector. To save valuable telemetry, the raw
data are reduced on board, including being inverted under the assumption of a
Milne-Eddington atmosphere, although simpler reduction methods are also
available on board. SO/PHI is composed of two telescopes; one, the Full Disc
Telescope (FDT), covers the full solar disc at all phases of the orbit, while
the other, the High Resolution Telescope (HRT), can resolve structures as small
as 200km on the Sun at closest perihelion. The high heat load generated through
proximity to the Sun is greatly reduced by the multilayer-coated entrance
windows to the two telescopes that allow less than 4% of the total sunlight to
enter the instrument, most of it in a narrow wavelength band around the chosen
spectral line