Search results for "image processing"
showing 10 items of 3285 documents
MRI using hyperpolarized noble gases.
1998
The aim of this study was to review the physical basis of MRI using hyperpolarized noble gases as well as the present status of preclinical and clinical applications. Non-radioactive noble gases with a nuclear spin 1/2 (He-3, Xe-129) can be hyperpolarized by optical pumping. Polarization is transferred from circularly polarized laser light to the noble-gas atoms via alkali-metal vapors (spin exchange) or metastable atoms (metastability exchange). Hyperpolarization results in a non-equilibrium polarization five orders of magnitude higher than the Boltzmann equilibrium compensating for the several 1000 times lower density of noble gases as compared with liquid state hydrogen concentrations in…
Automatically Detecting Incivility in Online Discussions of News Media
2018
Detecting biased language in written discourse is a highly relevant area of research in political communication and other social sciences, given the large quantity of information exchanged in public online platforms. In this abstract, we discuss an approach based on the concept of "incivility"-assessing biased text on the Facebook pages of established news media. News outlets are forced to put increasing efforts into preventing heated debates from turning into disrespectful discussions on their social media platforms. By scaling the analysis from a few thousand manually coded samples to more than a million comments, we take a step towards supporting media outlets in (semi-)automatizing the …
Housing Affordability and Income-threshold in Social Housing Policy
2016
Abstract The issue of affordable housing has again become crucial in ensuring a greater social equity, increasing social cohesion and reducing inequalities within metropolitan or regional systems which, in the current climate of severe economic crisis, have to respond to global challenges of development, innovation and sustainability. This study aims at building a system of knowledge about the housing affordability on the territorial scale, by which to identify the local characteristics of housing problems that could be solved through traditional planning tools or new practices of social housing, which involves private stakeholders and/or public administrations. This system of knowledge sho…
Measuring Uncertainty in the Portfolio Selection Problem
2018
In this paper, we propose a new index for ranking portfolios based on the credibility expected return and loss on their investment. We assume that the return on a given portfolio is modeled as a trapezoidal fuzzy variable, whose credibility distribution is built using the data set of its historical returns. The credibilistic loss on the investment for a given portfolio is measured by means of a suitable loss function. In order to take risk-adverse investor attitudes into account, we analyze the performance of some credibility measures related to loss and risk on the investment for a given portfolio and their relationship with similar possibility measures. A numerical example is presented sh…
Evaluating the Eco-Efficiency of Wastewater Treatment Plants: Comparison of Optimistic and Pessimistic Approaches
2020
The assessment of wastewater treatment plant (WWTP) performance has gained the interest of water utilities and water regulators. Eco-efficiency has been identified as a powerful indicator, as it integrates economic and environmental variables into a single index. Most previous studies have employed traditional data envelopment analysis (DEA) for the evaluation of WWTP eco-efficiency. However, DEA allows the selection of input and output weights for individual WWTPs for the calculation of eco-efficiency scores. To overcome this limitation, we employed the double-frontier and common set of weights methods to evaluate the eco-efficiency of a sample of 30 WWTPs in Spain. The WWTPs were ranked b…
Probabilistic inferences from conjoined to iterated conditionals
2017
Abstract There is wide support in logic, philosophy, and psychology for the hypothesis that the probability of the indicative conditional of natural language, P ( if A then B ) , is the conditional probability of B given A, P ( B | A ) . We identify a conditional which is such that P ( if A then B ) = P ( B | A ) with de Finetti's conditional event, B | A . An objection to making this identification in the past was that it appeared unclear how to form compounds and iterations of conditional events. In this paper, we illustrate how to overcome this objection with a probabilistic analysis, based on coherence, of these compounds and iterations. We interpret the compounds and iterations as cond…
Improving RF Fingerprinting Methods by Means of D2D Communication Protocol
2019
Radio Frequency (RF) fingerprinting is widely applied for indoor positioning due to the existing Wi-Fi infrastructure present in most indoor spaces (home, work, leisure, among others) and the widespread usage of smartphones everywhere. It corresponds to a simple idea, the signal signature in a location tends to be stable over the time. Therefore, with the signals received from multiple APs, a unique fingerprint can be created. However, the Wi-Fi signal is affected by many factors which degrade the positioning error range to around a few meters. This paper introduces a collaborative method based on device-to-device (D2D) communication to improve the positioning accuracy using only fingerprin…
A particle swarm approach for tuning washout algorithms in vehicle simulators
2018
Abstract The MCA tuning problem involves finding the most appropriate values for the parameters (or coefficients) of Motion Cueing Algorithms (MCA), also known as washout algorithms. These algorithms are designed to control the movements of the robotic mechanisms, referred to as motion platforms, employed to generate inertial cues in vehicle simulators. This problem can be approached in several different ways. The traditional approach is to perform a manual pilot-in-the-loop subjective tuning, using the opinion of several pilots/drivers to guide the process. A more systematic approach is to use optimization techniques to explore the vast parameter space of the MCA, using objective motion fi…
Similar morphokinetic patterns in embryos derived from obese and normoweight infertile women: a time-lapse study.
2013
Study question Does female obesity affect the dynamic parameters of embryo quality assessed by time-lapse analysis? Summary answer Female obesity does not affect the dynamic embryo quality as determined by image acquisition and time-lapse analysis. What is known already Female obesity impairs natural and assisted reproduction but there is no agreement on the specific contribution of gametes, embryos or endometrial receptivity. In this preliminary study the dynamic parameters of embryo quality are assessed for the first time by time-lapse analysis. Study design, size, duration Two-year cohort retrospective study comparing embryos from three groups of patients according to the presence of inf…
Behavior-based personalization in web search
2016
Personalized search approaches tailor search results to users' current interests, so as to help improve the likelihood of a user finding relevant documents for their query. Previous work on personalized search focuses on using the content of the user's query and of the documents clicked to model the user's preference. In this paper we focus on a different type of signal: We investigate the use of behavioral information for the purpose of search personalization. That is, we consider clicks and dwell time for reranking an initially retrieved list of documents. In particular, we (i) investigate the impact of distributions of users and queries on document reranking; (ii) estimate the relevance …