666 research outputs found
Group Based Interference Alignment
In the -user single-input single-output (SISO) frequency-selective fading
interference channel, it is shown that the maximal achievable multiplexing gain
is almost surely by using interference alignment (IA). However, when the
signaling dimensions are limited, allocating all the resources to all users
simultaneously is not optimal. So, a group based interference alignment (GIA)
scheme is proposed, and it is formulated as an unbounded knapsack problem.
Optimal and greedy search algorithms are proposed to obtain group patterns.
Analysis and numerical results show that the GIA scheme can obtain a higher
multiplexing gain when the resources are limited.Comment: 3 pages, 3 figures. resubmitted to IEEE Communications Letter
Physical representation of hillslope leaky barriers in 2D hydraulic models: A case study from the Calder Valley
The resources of small-scale community-based flood risk action groups are often limited, hence studies to model and predict the effects of Natural Flood Management are often restrained by time and lack of empirical data to validate results. As a result, representations of hillslope leaky barriers are largely modelled as several equifinal approaches, often without survey data. The geometrical characteristics of hillslope leaky barriers were surveyed for the first time at Hardcastle Crags, Calder Valley. This data informed six 2D hydraulic model representation scenarios with varying combinations of topography modification and roughness increase, allowing the sensitivity of their results to be tested. Results from Scenario 3 (topography modification and roughness increase) estimated total hillslope runoff peak flow to reduce by 16.6% in a 1:1-year design return period; however, this reduction diminished as rainfall intensity increased. Return periods of over 1:30 year estimated peak flow reductions of <5%. Only 14.3%–21.7% (98–148 m3) of the total additional storage provided by the barriers is mobilised during simulated events. A multi-peaked rainfall event from December 2015 was also simulated. Although the initial peak flow was reduced by 22.7%, as storage became mobilised, effectiveness reduced significantly for subsequent peaks within the same event
Critical Essay: Organizational cognitive neuroscience drives theoretical progress, or: The curious case of the straw man murder:organizational cognitive neuroscience drives theoretical progress, or: The curious case of the straw man murder
In this critical essay, we respond to Lindebaum’s (2016) argument that neuroscientific methodologies and data have been accepted prematurely in proposing novel management theory. We acknowledge that building new management theories requires firm foundations. We also find his distinction between demand and supply side forces helpful as an analytical framework identifying the momentum for the contemporary production of management theory. Nevertheless, some of the arguments Lindebaum (2016) puts forward, on closer inspection, can be contested, especially those related to the supply side of organizational cognitive neuroscience (OCN) research: fMRI data, motherhood statements and ethical concerns. We put forward a more positive case for OCN methodologies and data, as well as clarifying exactly what OCN really means, and its consequences for the development of strong management theory
A novel method for EOG features extraction from the forehead
Abstract — We have shown that the slow eye movements extracted from electrooculogram (EOG) signals can be used to estimate human vigilance in our previous work. However, the traditional method for recording EOG signals is to place the electrodes near the eyes of subjects. This placement is inconvenient for users in real-world applications. This paper aims to find a more practical placement for acquiring EOG signals for vigilance estimation. Instead of placing the electrodes near the eyes, we place them on the forehead. We extract EOG features from the forehead EOG signals using both independent component analysis and support vector machines. The performance of our proposed method is evaluated using the correlation coefficients between the forehead EOG signals and the traditional EOG signals. The results show that a correlation of 0.84 can be obtained when the users make 14 different face movements and for merely eye movements it reaches 0.93. I
Soil fungal community shift evaluation as a potential cadaver decomposition indicator
Fungi metabolise organic matter in situ and so alter both the bio-/physico-chemical properties and microbial community structure of the ecosystem. In particular, they are responsible reportedly for specific stages of decomposition. Therefore, this study aimed to extend previous bacteria-based forensic ecogenomics research by investigating soil fungal community and cadaver decomposition interactions in microcosms with garden soil (20 kg, fresh weight) and domestic pig (Sus scrofa domesticus) carcass (5 kg, leg). Soil samples were collected at depths of 0–10 cm, 10–20 cm and 20–30 cm on days 3, 28 and 77 in the absence (control −Pg) and presence (experimental +Pg) of Sus scrofa domesticus and used for total DNA extraction and nested polymerase chain reaction and denaturing gradient gel electrophoresis (PCR–DGGE) profiling of the 18S rRNA gene. The Shannon–Wiener (H′) community diversity indices were 1.25 ± 0.21 and 1.49 ± 0.30 for the control and experimental microcosms, respectively, while comparable Simpson species dominance (S) values were 0.65 ± 0.109 and 0.75 ± 0.015. Generally, and in contrast to parallel studies of the bacterial 16S rRNA and 16S rDNA profiles, statistical analysis (t-test) of the 18S dynamics showed no mathematically significant shifts in fungal community diversity (H′; p = 0.142) and dominance (S; p = 0.392) during carcass decomposition, necessitating further investigations
A Cooperative Coevolution Framework for Parallel Learning to Rank
Abstract—We propose CCRank, the first parallel framework for learning to rank based on evolutionary algorithms (EA), aiming to significantly improve learning efficiency while maintaining accuracy. CCRank is based on cooperative coevolution (CC), a divide-and-conquer framework that has demonstrated high promise in function optimization for problems with large search space and complex structures. Moreover, CC naturally allows parallelization of sub-solutions to the decomposed sub-problems, which can substantially boost learning efficiency. With CCRank, we investigate parallel CC in the context of learning to rank. We implement CCRank with three EA-based learning to rank algorithms for demonstration. Extensive experiments on benchmark datasets in comparison with the state-of-the-art algorithms show the performance gains of CCRank in efficiency and accuracy. Index Terms—Cooperative coevolution, learning to rank, information retrieval, genetic programming, immune programming Ç
Quinine doped hybrid sol-gel coatings for wave guiding and optical applications
Pure and quinine doped silica coatings have been prepared over sodalime glasses. The coatings were consolidated at low temperature (range 60-180 A degrees C) preserving optical activity of quinine molecule. We designed a device to test the guiding properties of the coatings. We confirmed with this device that light injected in pure silica coatings is guided over distances of meters while quinine presence induces isotropic photoluminescence. With the combined use of both type of coatings, it is possible to design light guiding devices and illuminate regions in glass elements without electronic circuits
The initial step of DNA hairpin folding: a kinetic analysis using fluorescence correlation spectroscopy
Conformational fluctuations of single-stranded DNA (ssDNA) oligonucleotides were studied in aqueous solution by monitoring contact-induced fluorescence quenching of the oxazine fluorophore MR121 by intrinsic guanosine residues (dG). We applied fluorescence correlation spectroscopy as well as steady-state and time-resolved fluorescence spectroscopy to analyze kinetics of DNA hairpin folding. We first characterized the reporter system by investigating bimolecular quenching interactions between MR121 and guanosine monophosphate in aqueous solution estimating rate constants, efficiency and stability for formation of quenched complexes. We then studied the kinetics of complex formation between MR121 and dG residues site-specifically incorporated in DNA hairpins. To uncover the initial steps of DNA hairpin folding we investigated complex formation in ssDNA carrying one or two complementary base pairs (dC–dG pairs) that could hybridize to form a short stem. Our data show that incorporation of a single dC–dG pair leads to non-exponential decays for opening and closing kinetics and reduces rate constants by one to two orders of magnitude. We found positive activation enthalpies independent of the number of dC–dG pairs. These results imply that the rate limiting step of DNA hairpin folding is not determined by loop dynamics, or by mismatches in the stem, but rather by interactions between stem and loop nucleotides
Optimization of PCR conditions to amplify microsatellite loci in the bunchgrass lizard (Sceloporus slevini) genomic DNA
<p>Abstract</p> <p>Background</p> <p>Microsatellites, also called Simple Sequence Repeats (SSRs), repetitions of nucleotide motifs of 1-5 bases, are currently the markers of choice due to their abundant distribution in the genomes, and suitability for high-throughput analysis. A total of five different primer pairs were optimized for polymerase chain reaction (PCR) to amplify microsatellite loci in total genomic DNA of bunchgrass lizards (<it>Sceloporus slevini</it>) collected from three sites in southeastern Arizona; the Sonoita Plain, Chiricahua Mountains and Huachuca Mountains.</p> <p>Findings</p> <p>The primers used for current investigation were originally designed for the Eastern Fence Lizard (<it>Sceloporus undulatus</it>). Five primer pairs were selected based on annealing temperatures for optimizing the PCR conditions to amplify with bunchgrass lizards. Different concentrations of DNA and annealing temperature were optimized. While keeping other reagents constant, a DNA concentration, 37.5 ng in the final reaction volume and PCR conditions of an initial denaturation of 94°C for five minutes, an annealing temperature of 55°C and final extension of 72°C for four minutes gave the best amplification for all the primer pairs.</p> <p>Conclusions</p> <p>Modifying the standard protocol for annealing temperatures and final extension time increases the success of cross amplification of specific microsatellite loci in the bunchgrass lizard. A loading volume of 5 ul DNA at a concentration of 10 ng/ul and a 2% agarose for gel electrophoresis were observed the best for cross amplification of selected five primer pairs on bunch grass lizard.</p> <p>Trial Registration</p> <p>The research was conducted with Arizona Game and Fish Department scientific collecting permits SP565256, SP657407 & SP749119 to Dr. Christian A d'Orgeix.</p
Observation of Static Pictures of Dynamic Actions Enhances the Activity of Movement-Related Brain Areas
Physiological studies of perfectly still observers have shown interesting correlations between increasing effortfulness of observed actions and increases in heart and respiration rates. Not much is known about the cortical response induced by observing effortful actions. The aim of this study was to investigate the time course and neural correlates of perception of implied motion, by presenting 260 pictures of human actions differing in degrees of dynamism and muscular exertion. ERPs were recorded from 128 sites in young male and female adults engaged in a secondary perceptual task.Our results indicate that even when the stimulus shows no explicit motion, observation of static photographs of human actions with implied motion produces a clear increase in cortical activation, manifest in a long-lasting positivity (LP) between 350–600 ms that is much greater to dynamic than less dynamic actions, especially in men. A swLORETA linear inverse solution computed on the dynamic-minus-static difference wave in the time window 380–430 ms showed that a series of regions was activated, including the right V5/MT, left EBA, left STS (BA38), left premotor (BA6) and motor (BA4) areas, cingulate and IF cortex.Overall, the data suggest that corresponding mirror neurons respond more strongly to implied dynamic than to less dynamic actions. The sex difference might be partially cultural and reflect a preference of young adult males for highly dynamic actions depicting intense muscular activity, or a sporty context
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