315 research outputs found
Channel estimation and symbol detection for block transmission using data-dependent superimposed training
We address the problem of frequency-selective
channel estimation and symbol detection using superimposed
training. The superimposed training consists of the sum of a known sequence and a data-dependent sequence that is unknown to the receiver. The data-dependent sequence cancels the effects of the unknown data on channel estimation. The performance of the proposed approach is shown to significantly outperform existing methods based on superimposed training (ST)
EM Algorithms for Weighted-Data Clustering with Application to Audio-Visual Scene Analysis
Data clustering has received a lot of attention and numerous methods,
algorithms and software packages are available. Among these techniques,
parametric finite-mixture models play a central role due to their interesting
mathematical properties and to the existence of maximum-likelihood estimators
based on expectation-maximization (EM). In this paper we propose a new mixture
model that associates a weight with each observed point. We introduce the
weighted-data Gaussian mixture and we derive two EM algorithms. The first one
considers a fixed weight for each observation. The second one treats each
weight as a random variable following a gamma distribution. We propose a model
selection method based on a minimum message length criterion, provide a weight
initialization strategy, and validate the proposed algorithms by comparing them
with several state of the art parametric and non-parametric clustering
techniques. We also demonstrate the effectiveness and robustness of the
proposed clustering technique in the presence of heterogeneous data, namely
audio-visual scene analysis.Comment: 14 pages, 4 figures, 4 table
The removal of thermally aged films of triacylglycerides by surfactant solutions
Thermal ageing of triacylglycerides (TAG) at high temperatures produces films which resist removal using aqueous surfactant solutions. We used a mass loss method to investigate the removal of thermally aged TAG films from hard surfaces using aqueous solutions of surfactants of different charge types. It was found that cationic surfactants are most effective at high pH, whereas anionics are most effective at low pH and a non-ionic surfactant is most effective at intermediate pH. We showed that the TAG film removal process occurs in several stages. In the first ‘‘lag phase’’ no TAG removal occurs; the surfactant first partitions into the thermally aged film. In the second stage, the TAG film containing surfactant was removed by solubilisation into micelles in the aqueous solution. The effects of pH and surfactant charge on the TAG removal process correlate with the effects of these variables on the extent of surfactant partitioning to the TAG film and on the maximum extent of TAG solubilisation within the micelles. Additionally, we showed how the TAG removal is enhanced by the addition of amphiphilic additives such as alcohols which act as co-surfactants. The study demonstrates that aqueous surfactant solutions provide a viable and more benign alternative to current methods for the removal of thermally aged TAG films
The Arts and Technology: How Educational Technology Can Bring Humanities Further Into Elementary and Primary School Systems
As the world becomes more inclined to implement technology in nearly every aspect of society, the United States Department of Education must find a way to incorporate new styles of modern and high-tech teaching without pushing out certain subjects from its curriculum. I believe technology can be used to bring the Humanities further into the classroom. In today’s society American education programs are desperately trying to make up for subpar primary school scores in mathematics and science. According to the government accredited international education forum (the Organization for Economic Co-operation and Development) the United States was found to be below the OECD average in science ranking 25th, reading 24th and mathematics 41st (Businessinsider.com). With these mediocre scores the United States has been forced to take drastic measure in bolstering its primary education systems. While an added emphasis in elementary math and science curriculum is an obvious route, it seems that the removal or distancing from the arts and other social forms of education has also become part of the solution. While science, technology, engineering and math are all extremely important, the United States Department of Education should be able to recommend modernized approaches that incorporate art history, history, literature, art, music, philosophy and language. In our ever-changing high-tech world, the Humanities are needed in our classrooms to supply equality and perspective. The Humanities widen our thought process, build global understanding, assist in the formation of critical thinking skills, train individuals to communicate and share, bolster moral accountability and cultural sensitivity, support scientific advancements through unique societal perspectives, guide humanity towards a more rational and inclusive way of thinking, and create a well-balanced 21st century scholar. In today’s modern society it is more than reasonable to explore options that involve the intertwining of technology and the arts in our elementary school systems. It must also be mentioned, the goal of this paper is to in now way lessen or devalue the role of the instructor, rather, the research provided is aimed at highlighting certain types of technologies that can potentially assist primary and elementary educators who aspire to further incorporate the Humanities and its core philosophies into their curriculum
Recognition memory deficits in mild cognitive impairment
There is no agreement on the pattern of recognition memory deficits characteristic of patients diagnosed with mild cognitive impairment (Mel). Whereas lower performance in recollection is the hallmark of Mel, there is a strong controversy about possible deficits in familiarity estimates when using recognition memory tasks. The aim of this research is to shed Iight on the pattern of responding in recollection and familiarity in MCl. Five groups of participants were tested. The main participant samples were those formed by two Mel groups differing in age and an Alzheimer's disease group (AD), which were compared with two control groups, Whereas one of the control groups served to assess the performance of the MeI and AD people, the other one, composed of young healthy participants, served the purpose of evaluating the adequacy of the experimental tasks used in the evaluation of the different components of recognition memory. We used an associative recognition task as a direct index of recollection and a choice task on a pair of stimuli, one of which was perceptually similar to those studied in the associative recognition phase, as an index of familiarity. Our results indicate that recollection decreases with age and neurological status, and familiarity remains stable in the elderly control sample but it is deficient in Me!. This research shows that a unique encoding situation generated deficits in recollective and familiarity mechanisms in mild cognitive impaired individuals, providing evidence for the existence of deficits in both retrieval processes in recognition memory in a MeI stage
Exploring Recollection and Familiarity Impairments in Parkinson´s disease
There is conflicting evidence on whether patients diagnosed with Parkinson's disease (PD) have cognitive deficits associated with episodic memory and particularly with recognition memory. The aim of the present study was to explore whether PD patients exhibit deficits in recollection and familiarity, the two processes involved in recognition. A sample of young healthy participants (22) was tested to verify that the experimental tasks were useful estimators of recognition processes. Two further samples ¿ one of elderly controls (16) and one of PD patients (20) ¿ were the main focus of this research. All participants were exposed to an associative recognition task aimed at estimating recollection followed by a two-alternative forced-choice (2AFC) test designed to estimate familiarity. The analyses showed a deficit in associative recognition in PD patients and no difference between elderly controls and PD patients in the 2AFC test. By contrast, young healthy participants were better than elderly controls and PD patients in both components of recognition. Further analyses of results of the 2AFC test indicated that the measure chosen to estimate conceptual familiarity was adequate
Use of multiple polygenic risk scores for distinguishing schizophrenia-spectrum disorder and affective psychosis categories in a first-episode sample; the eu-gei study
This work was supported by funding from the European Community’s Seventh Framework Programme under grant agreement No. HEALTH-F2-2010-241909 (Project EU-GEI). (...) CA was supported by the Spanish Ministry of Science and Innovation; Instituto de Salud Carlos III (SAM16PE07CP1, PI16/02012, PI19/024), co-financed by ERDF Funds from the European Commission, ‘A way of making Europe’, CIBERSAM. Madrid Regional Government (B2017/BMD-3740 AGES-CM-2), Fundación Familia Alonso and Fundación Alicia Koplowitz. MB was supported by the Ministry of Economy and Competitivity (PI08/0208; PI11/00325; PI14/00612), Instituto de Salud Carlos III – ERDF Funds from the European Commission, ‘A way of making Europe’, CIBERSAM, by the CERCA Programme/Generalitat de Catalunya and Secretaria d’Universitats i Recerca del Departament d’Economia I Coneixement (2017SGR1355). Departament de Salut de la Generalitat de Catalunya, en la convocatoria corresponent a l’any 2017 de concessió de subvencions del PERIS 2016-2020, modalitat Projectes de recerca orientats a l’atenció primària, amb el codi d’expedient SLT006/17/00345; and grateful for the support of the Institut de Neurociències, Universitat de Barcelona.Rodriguez V., Alameda L., Quattrone D., Tripoli G., Gayer-Anderson C., Spinazzola E., Trotta G., Jongsma H.E., Stilo S., La Cascia C., Ferraro L., La Barbera D., Lasalvia A., Tosato S., Tarricone I., Bonora E., Jamain S., Selten J.-P., Velthorst E., De Haan L., Llorca P.-M., Arrojo M., Bobes J., Bernardo M., Arango C., Kirkbride J., Jones P.B., Rutten B.P., Richards A., Sham P.C., O'Donovan M., Van Os J., Morgan C., Di Forti M., Murray R.M., Vassos E
Rational Design of Superhydrophilic/Superoleophobic Surfaces for Oil-Water Separation via Thiol-Acrylate Photopolymerization
We report a simple, rapid, and scalable strategy to fabricate surfaces exhibiting in-air superoleophobic/superhydrophilic wetting via sequential spray deposition and photopolymerization of nanoparticle-laden thiol–acrylate resins comprising both hydrophilic and oleophobic chemical constituents. The combination of spray deposition with nanoparticles provides hierarchical surface morphologies with both micro- and nanoscale roughness. Mapping the wetting behavior as a function of resin composition using high- and low-surface-tension liquid probes enabled facile identification of coatings that exhibit a range of wetting behavior, including superhydrophilic/superoleophilic, superhydrophobic/superoleophobic, and in-air superhydrophilic/superoleophobic wetting. In-air superhydrophilic/superoleophobic wetting was realized by a dynamic rearrangement of the interface to expose a greater fraction of hydrophilic moieties in response to contact with water. We show that these in-air superoleophobic/superhydrophilic coatings deposited onto porous supports enable separation of model oil–water emulsions with separation efficiencies up to 99.9% with 699 L·m–2 h–1 permeate flux when the superhydrophilic/superoleophobic coatings are paired with 0.45 μm nylon membrane supports
Tailoring block copolymer nanoporous thin films with acetic acid as a small guest molecule
Block copolymers offer the fabrication of mesoporous thin films with distinct nanoscale structural features. In this contribution, we present the use of acetic acid (CH3COOH) as a low‐molecular‐weight guest molecule to tune the supramolecular assembly of poly[styrene‐block‐(4‐vinylpyridine)] (PS‐b‐P4VP), offering a versatile and straightforward method to obtain tailored nanostructured films with controlled topography and pore size. Spin‐coating toluene solutions of PS‐b‐P4VP, with a variable amount of CH3COOH, leads to micellar thin films, where the micelles contain the carboxylic acid as a guest molecule. The size can be conveniently modified in these films (from 48 to 75 nm) by varying the amount of organic acid in the starting solutions. Subsequent surface reconstruction of micellar films using ethanol leads to ring‐shaped copolymer nanoporous films with modulated diameter. Controlling the micelle reconstruction process, cylindrical porous films are also obtained. Interestingly, changing the type of aliphatic carboxylic acid leads to a modification of the observed film morphology from micelles to out‐of‐plane P4VP cylinders (or lamellae) in a PS matrix
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