1,327 research outputs found
A deconvolution map-making method for experiments with circular scanning strategies
Aims. To investigate the performance of a deconvolution map-making algorithm
for an experiment with a circular scanning strategy, specifically in this case
for the analysis of Planck data, and to quantify the effects of making maps
using simplified approximations to the true beams. Methods. We present an
implementation of a map-making algorithm which allows the combined treatment of
temperature and polarisation data, and removal of instrumental effects, such as
detector time constants and finite sampling intervals, as well as the
deconvolution of arbitrarily complex beams from the maps. This method may be
applied to any experiment with a circular scanning-strategy. Results.
Low-resolution experiments were used to demonstrate the ability of this method
to remove the effects of arbitrary beams from the maps and to demonstrate the
effects on the maps of ignoring beam asymmetries. Additionally, results are
presented of an analysis of a realistic full-scale simulated data-set for the
Planck LFI 30 GHz channel. Conclusions. Our method successfully removes the
effects of the beams from the maps, and although it is computationally
expensive, the analysis of the Planck LFI data should be feasible with this
approach.Comment: 14 pages, 14 figures, accepte
Iterative destriping and photometric calibration for Planck-HFI, polarized, multi-detector map-making
We present an iterative scheme designed to recover calibrated I, Q, and U
maps from Planck-HFI data using the orbital dipole due to the satellite motion
with respect to the Solar System frame. It combines a map reconstruction, based
on a destriping technique, juxtaposed with an absolute calibration algorithm.
We evaluate systematic and statistical uncertainties incurred during both these
steps with the help of realistic, Planck-like simulations containing CMB,
foreground components and instrumental noise, and assess the accuracy of the
sky map reconstruction by considering the maps of the residuals and their
spectra. In particular, we discuss destriping residuals for polarization
sensitive detectors similar to those of Planck-HFI under different noise
hypotheses and show that these residuals are negligible (for intensity maps) or
smaller than the white noise level (for Q and U Stokes maps), for l > 50. We
also demonstrate that the combined level of residuals of this scheme remains
comparable to those of the destriping-only case except at very low l where
residuals from the calibration appear. For all the considered noise hypotheses,
the relative calibration precision is on the order of a few 10e-4, with a
systematic bias of the same order of magnitude.Comment: 18 pages, 21 figures. Match published versio
Estado actual de la técnica y cuestiones perdurables en la recogida de datos antropométricos
The study of human body size and shape has been a topic of research for a very long time. In the past, anthropometry used traditional measuring techniques to record the dimensions of the human body and reported variance in body dimensions as a function of mean and standard deviation. Nowadays, the study of human body dimensions can be carried out more efficiently using three-dimensional body scanners, which can provide large amounts of anthropometric data more quickly than traditional techniques can. This paper presents a description of the broad range of issues related to the collection of anthropometric data using three-dimensional body scanners, including the different types of technologies available and their implications, the standard scanning process needed for effective data collection, and the possible sources of measurement errors that might affect the reliability and validity of the data collected.El estudio del tamaño y la forma del cuerpo humano ha sido un tema de investigación durante un tiempo muy largo. En el pasado, la antropometría utilizó técnicas de medición tradicionales para registrar las dimensiones del cuerpo humano y reportó la variación en las dimensiones del cuerpo en función de la media y la desviación estándar. Hoy en día, el estudio de las dimensiones del cuerpo humano se puede llevar a cabo utilizando maneras más eficientes, como los escáneres tridimensionales del cuerpo, que pueden proporcionar grandes cantidades de datos antropométricos más rápidamente que las técnicas tradicionales. En este trabajo se presenta una descripción de la amplia gama de temas relacionados con la recogida de datos antropométricos utilizando escáneres tridimensionales del cuerpo, incluyendo los diferentes tipos de tecnologías disponibles y sus implicaciones, el proceso de digitalización estándar necesario para la captura efectiva de datos, y las posibles fuentes de los errores de medición que podrán afectar la fiabilidad y validez de los datos recogidos.This work is financed by FEDER funds through the Competitive Factors Operational Program (COMPETE) POCI-01-0145-FEDER-007043 and POCI-01-0145FEDER-007136 and by national funds through FCT – the Portuguese Foundation for Science and Technology, under the projects UID/CEC/00319/2013 and UID/CTM/00264 respectively
Map-making in small field modulated CMB polarisation experiments: approximating the maximum-likelihood method
Map-making presents a significant computational challenge to the next
generation of kilopixel CMB polarisation experiments. Years worth of time
ordered data (TOD) from thousands of detectors will need to be compressed into
maps of the T, Q and U Stokes parameters. Fundamental to the science goal of
these experiments, the observation of B-modes, is the ability to control noise
and systematics. In this paper, we consider an alternative to the
maximum-likelihood method, called destriping, where the noise is modelled as a
set of discrete offset functions and then subtracted from the time-stream. We
compare our destriping code (Descart: the DEStriping CARTographer) to a full
maximum-likelihood map-maker, applying them to 200 Monte-Carlo simulations of
time-ordered data from a ground based, partial-sky polarisation modulation
experiment. In these simulations, the noise is dominated by either detector or
atmospheric 1/f noise. Using prior information of the power spectrum of this
noise, we produce destriped maps of T, Q and U which are negligibly different
from optimal. The method does not filter the signal or bias the E or B-mode
power spectra. Depending on the length of the destriping baseline, the method
delivers between 5 and 22 times improvement in computation time over the
maximum-likelihood algorithm. We find that, for the specific case of single
detector maps, it is essential to destripe the atmospheric 1/f in order to
detect B-modes, even though the Q and U signals are modulated by a half-wave
plate spinning at 5-Hz.Comment: 18 pages, 17 figures, MNRAS accepted v2: content added (inc: table
2), typos correcte
CHILD SAFETY FEATURES
A system may include computing devices (e.g., a mobile phone, a tablet computer, a laptop computer, a wearable device, a tracking tag, an Internet of Things (IoT) booster seat, an IoT adaptive headrest, etc.) and vehicles (e.g., an automobile, a motorcycle, a bus, a recreational vehicle (RV), a semi-trailer truck, a tractor or other type of farm equipment, train, a plane, a boat, a helicopter, a personal transport vehicle, etc.). Based on a location of a child with respect to the vehicles (which may be determined using, e.g., Bluetooth™, ultra-wideband technology, sensors of the vehicles, etc.), the system may perform actions to improve child safety. For example, based on the location of the child, the vehicles may change vehicle settings to those suitable for a child (e.g., enable child safety locks, disable power window controls in the rear seats, adjust airbag deployment based on the presence and size of the child, etc.). In this way, the techniques may facilitate the implementation of protection measures for children, ensuring their safety in and near vehicles
An Automated Meeting Assistant: A Tangible Mixed Reality Interface for the AMIDA Automatic Content Linking Device
We describe our approach to support ongoing meetings with an automated meeting assistant. The system based on the AMIDA Content Linking Device aims at providing relevant documents used in previous meetings for the ongoing meeting based on automatic speech recognition. Once the content linking device finds documents linked to a discussion about a similar subject in a previous meeting, it assumes they may be relevant for the current discussion as well. We believe that the way these documents are offered to the meeting participants is equally important as the way they are found. We developed a mixed reality, projection based user interface that lets the documents appear on the table tops in front of the meeting participants. They can hand them over to others or bring them onto the shared projection screen easily if they consider them relevant. Yet, irrelevant documents don't draw too much attention from the discussion. In this paper we describe the concept and implementation of this user interface and provide some preliminary results
The 20th anniversary of interleukin-2 therapy: Bimodal role explaining longstanding random induction of complete clinical responses
Background: This year marks the twentieth anniversary of the approval by the US Food and Drug Administration of interleukin-2 (IL2) for use in cancer therapy, initially for renal cell carcinoma and later for melanoma. IL2 therapy for cancer has stood the test of time, with continued widespread use in Europe, parts of Asia, and the US. Clinical complete responses are variably reported at 5%–20% for advanced malignant melanoma and renal cell carcinoma, with strong durable responses and sustained long-term 5–10-year survival being typical if complete responses are generated. Methods: The literature was reviewed for the actions and clinical effects of IL2 on subsets of T cells. The influence of IL2 on clinical efficacy was also sought. Results: The review revealed that IL2 is capable of stimulating different populations of T cells in humans to induce either T effector or T regulatory responses. This apparent "functional paradox" has confounded a clear understanding of the mechanisms behind the clinical effects that are observed during and following administration of IL2 therapy. An average complete response rate of around 7% in small and large clinical trials using IL2 for advanced renal cell carcinoma and malignant melanoma has been shown from a recent review of the literature. Conclusion: This review considers the published literature concerning the actions and emerging clinical effects of IL2 therapy, spanning its 20-year period in clinical use. It further details some of the recently described "bimodal" effects of IL2 to explain the apparent functional paradox, and how IL2 might be harnessed to emerge rapidly as a much more effective and predictable clinical agent in the near future.Brendon J Coventry, Martin L Ashdow
Planck 2018 results. XI. Polarized dust foregrounds
The study of polarized dust emission has become entwined with the analysis of the cosmic microwave background (CMB) polarization in the quest for the curl-like B-mode polarization from primordial gravitational waves and the low-multipole E-mode polarization associated with the reionization of the Universe. We used the new Planck PR3 maps to characterize Galactic dust emission at high latitudes as a foreground to the CMB polarization and use end-to-end simulations to compute uncertainties and assess the statistical significance of our measurements. We present Planck EE, BB, and TE power spectra of dust polarization at 353 GHz for a set of six nested high-Galactic-latitude sky regions covering from 24 to 71% of the sky
Fast Pixel Space Convolution for CMB Surveys with Asymmetric Beams and Complex Scan Strategies: FEBeCoP
Precise measurement of the angular power spectrum of the Cosmic Microwave
Background (CMB) temperature and polarization anisotropy can tightly constrain
many cosmological models and parameters. However, accurate measurements can
only be realized in practice provided all major systematic effects have been
taken into account. Beam asymmetry, coupled with the scan strategy, is a major
source of systematic error in scanning CMB experiments such as Planck, the
focus of our current interest. We envision Monte Carlo methods to rigorously
study and account for the systematic effect of beams in CMB analysis. Toward
that goal, we have developed a fast pixel space convolution method that can
simulate sky maps observed by a scanning instrument, taking into account real
beam shapes and scan strategy. The essence is to pre-compute the "effective
beams" using a computer code, "Fast Effective Beam Convolution in Pixel space"
(FEBeCoP), that we have developed for the Planck mission. The code computes
effective beams given the focal plane beam characteristics of the Planck
instrument and the full history of actual satellite pointing, and performs very
fast convolution of sky signals using the effective beams. In this paper, we
describe the algorithm and the computational scheme that has been implemented.
We also outline a few applications of the effective beams in the precision
analysis of Planck data, for characterizing the CMB anisotropy and for
detecting and measuring properties of point sources.Comment: 26 pages, 15 figures. New subsection on beam/PSF statistics, new and
better figures, more explicit algebra for polarized beams, added explanatory
text at many places following referees comments [Accepted for publication in
ApJS
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