Function Of Relative Distance Research Articles

Analytical Solution for Optimum Design of Nozzle Discharge Lines Based on Hydraulic Considerations

This study focuses on finding the best design of nozzles used in the water discharge pipelines delivering free jets based on hydraulic considerations. An analytical solution is carried out to determine the best design for these nozzles. The solution depends on the derivative method applied to the energy head concerning the nozzle diameter to maximize the power of the jet. The equation derived for computing the best pipe-nozzle diameter ratio D/d in discharge lines applies over practical ranges of relative distance L/D (50-500) and relative roughness e/D (0.01-0.05). An illustrative example is solved and gives D/d = 1.8858 (closely equal to 1.9), the deviation is 0.77%, which is firmly accepted. The equation holds good for D/d from 1.4 to 3.584 and could be applied to compute D/d ratios without the need for a computer program. In the derived equation, D/d is a function of relative distance L/D, and friction factor F with negligible computational errors. The derived equation when compared with the conventional one, shows an increase in the computed power of the jet ranging from 12.5 to 19.23%. The evaluation study reflects the rigidity of the derived equations and their reliability in computing the best pipe-nozzle diameter ratios in discharge lines delivering free jets with reasonable powers, while the conventional formula is approximate. However, many engineering applications of water jet nozzles are used in; impulsive turbines, power-delivering free jets, water filters, flotation tanks, sedimentation tanks, water storage tanks, trickling filters, and other water and wastewater systems.

A new tool for conjunction analysis of ISRO's operational satellites, Close Approach Prediction Software: CLAPS

During the lifetime of an operational spacecraft, a situation may occur when it faces a close approach with other orbiting space objects. The mitigation strategy for minimizing threat from orbiting space objects is to first carry out proximity analysis for operational spacecraft's (primary) with all other catalogued orbiting space objects (secondary). In case of a possible close approach, to plan an evasive collision avoidance maneuver. The ever-increasing number of space objects around the Earth demands this kind of analysis on daily basis by satellite operators. Presently, ISRO is operating close to 50 satellites in LEO and GEO/GSO orbits and this number is increasing each year at a rapid rate. At present the NORAD TLE catalogue consists of more than 18000 unclassified space objects. The large number of object pairs require enormous amount of computational load to do such kind of analysis on daily basis. Therefore, an efficient and user-friendly tool to predict the future close approaches is necessary for satellite operators.In this paper, methodology is designed and developed for carrying out conjunction analysis for all operational satellites with catalogued space objects. In the design, efficient approach is adopted to reduce the computation time. Each object pair goes through screening process using pre-filters like perigee-apogee test and smart sieves. These filters are based on basic flight dynamics rules. Only those pairs which are passed by all filters are subjected to relative distance function method for finer assessment. For the candidate pairs which violate the specified minimum Inter-Satellite-Distance (ISD) limit, collision probability is computed. For operational satellites, latest available orbit determination results at control centre are used and orbit propagation is done with high fidelity ephemeris model. Orbit propagation of catalogued objects with TLE is done using SGP4 model. Using this design methodology, Close Approach Prediction Software (CLAPS) is developed in C++ language, to predict the future close approaches for multiple operational satellites with complete TLE catalogue in single run.CLAPS s/w is tested for various close encounter cases and results are validated with STK's AdvCAT tool. The close approach time and minimum distance are found to match up to millisecond and millimetre level respectively. The results of few actual close approach scenarios are presented and discussed. CLAPS is being used regularly at ISRO's Master Control Facility, Hassan for routine monitoring of close approaches.

Benchmarking PBE+D3 and SCAN+rVV10 methods using potential energy surfaces generated with MP2+ΔCCSD(T) calculation

We develop a benchmark system for van der Waals interactions obtained with MP2+ΔCCSD(T) method at complete basis set limit. With this benchmark, we examine the widely used PBE+D3 method and recently developed SCAN+rVV10 method for density functional theory calculations. Our benchmark is based on two molecules: glycine (or Gly, an amino acid) and uracil (or U, an RNA base). We consider six dimer configurations of the two monomers and their potential energy surfaces as a function of relative distance and rotation angle. The Gly-Gly, Gly-U, and U-U pairs represent London dispersion, hydrogen bonding, and π–π stacking interactions, respectively. Our results show that both PBE+D3 and SCAN+rVV10 methods can yield accuracy better than 1 kcal/mol, except for the cases when the distance between the two monomers is significantly smaller than the equilibrium distance. In such a case, neither of these methods can yield uniformly accurate results for all the configurations. In addition, it is found that the SCAN and SCAN+rVV10 methods can reproduce some subtle features in a rotational potential energy curve, while the PBE, PBE+D3, and the local density approximation fail.

Semi-supervised orthogonal discriminant analysis with relative distance : integration with a MOO approach

In discriminant analysis, trace ratio is an important criterion for minimizing the between-class similarity and maximizing the within-class similarity, simultaneously. In brief, we address the trace ratio problem associated with many semi-supervised discriminant analysis algorithms as they use the normal Euclidean distances between training data samples. Based on this problem, we propose a new semi-supervised orthogonal discriminant analysis technique with relative distance constraints called SSODARD. Different from the existing semi-supervised dimensionality reduction algorithms, our algorithm is more consistent in propagating the label information from the labeled data to the unlabeled data because of the use of relative distance function instead of normal Euclidean distance function. For finding this appropriate relative distance function, we use pairwise constraints generated from labeled data and satisfy them using Bregman projection. Since the projection is not orthogonal, we require an appropriate subset of constraints. In order to select such a subset of constraints, we further develop a framework called MO-SSODARD, which uses evolutionary algorithm while optimizing various validity indices simultaneously. The experimental results on various datasets show that our proposed approaches are superior than the state-of-the-art discriminant algorithms with respect to various validity indices.

Summary statistical representation of temporal frequency

Observers effortlessly extract global patterns of spatiotemporal features from multiple objects in dynamic scenes (e.g., the movement of a crowd). Studies have revealed that a variety of spatial features are efficiently integrated into ensemble representations (e.g., mean), even when displayed in temporally complex contexts. However, it is not yet clear whether the ensemble coding also applies to purely temporal features such as frequency. Here, we investigated whether the visual system can extract the mean frequency from a group of flickering objects and how many objects are integrated into this representation of ensemble temporal frequency. In the Experiment 1, the display contained four disks flickering at independent frequencies in parallel for 4 seconds. Participants reported whether the mean of display frequency was higher or lower than a subsequent single test flicker. Temporal frequencies for the display disks were extracted randomly from one of three distributions (positively-skewed, symmetric, or negatively-skewed in a range of 0.5 to 12 Hz.) Points of subjective equality (PSEs) for the estimated means significantly shifted in accordance with the means of the three distributions. In Experiment 2, we displayed a full group of 8 disks or subsets of them (1, 2, or 4 disks) and participants compared the mean of the displayed disks with the subsequent test flicker frequency. We plotted the data as a function of relative distance between the mean of all the 8 frequencies and the test flicker, and observed a trend that participants' sensitivity improved as the number of displayed disks increased, at least up to four disks. However, this effect was not very large, suggesting that participants could integrate multiple temporal frequencies and extract the mean from them, but the efficiency of integration was not as high as other low-level visual features such as size and orientation. Meeting abstract presented at VSS 2017

An Improved Artificial Potential Field for Unmanned Aerial Vehicles Path Planning

There are still some problems existing in the Olfati-Saber potential function, such as easily getting into local standstill and GNRON. Introducing a relative distance function and creating local virtual goal by using fan gird, an improved artificial potential field was proposed so as to solve those issues. The local virtual goal is created by finding the minimum positive characterization value which contains all potential energy in the sector and the degree of deviation of the goal lines. In return, based on APF, the local path is planned. The simulation results show that the improved algorithm can find a smooth and safe path for requirements of UAV. The proposed algorithm is simple and feasible with strong searching and adaptability.

The Use of Modified Annandale’s Method in the Estimation of the Sediment Distribution in Small Reservoirs—A Case Study

In the current study, the applicability of the Annandale method was verified based on the results of silting and sediment distribution measurements carried out in eight small reservoirs, with a capacity that does not exceed 5 million m3. It was found that the application of this method is possible only in the case of small reservoirs, in which the sediment load is deposited in the near-dam zone. The results of studies conducted on small reservoirs allowed the construction of a graph presenting the relationship of a sum of dimensionless sediment load volume as a function of relative distance from the dam, which became the modification of the graph in Annandale’s method. The proposed modification of Annandale’s method considers reservoirs with a length less than 1000 m and capacity-inflow ratio ranging from a few per mille to a percent.

The importance of microstructural variations on the fracture toughness of human dentin

The crack growth resistance of human dentin was characterized as a function of relative distance from the DEJ and the corresponding microstructure. Compact tension specimens were prepared from the coronal dentin of caries-free 3rd molars. The specimens were sectioned from either the outer, middle or inner dentin. Stable crack extension was achieved under Mode I quasi-static loading, with the crack oriented in-plane with the tubules, and the crack growth resistance was characterized in terms of the initiation (Ko), growth (Kg) and plateau (Kp) toughness. A hybrid approach was also used to quantify the contribution of dominant mechanisms to the overall toughness. Results showed that human dentin exhibits increasing crack growth resistance with crack extension in all regions, and that the fracture toughness of inner dentin (2.2 ± 0.5 MPa·m0.5) was significantly lower than that of middle (2.7 ± 0.2 MPa·m0.5) and outer regions (3.4 ± 0.3 MPa·m0.5). Extrinsic toughening, composed mostly of crack bridging, was estimated to cause an average increase in the fracture energy of 26% in all three regions. Based on these findings, dental restorations extended into deep dentin are much more likely to cause tooth fracture due to the greater potential for introduction of flaws and decrease in fracture toughness with depth.

Attention Reshapes Center-Surround Receptive Field Structure in Macaque Cortical Area MT

Directing spatial attention to a location inside the classical receptive field (cRF) of a neuron in macaque medial temporal area (MT) shifts the center of the cRF toward the attended location. Here we investigate the influence of spatial attention on the profile of the inhibitory surround present in many MT neurons. Two monkeys attended to the fixation point or to 1 of 2 random dot patterns (RDPs) placed inside or next to the cRF, whereas a third RDP (the probe) was briefly presented in quick succession across the cRF and surround. The probe presentation responses were used to compute a map of the excitatory receptive field and its inhibitory surround. Attention systematically reshapes the receptive field profile, independently shifting both center and surround toward the attended location. Furthermore, cRF size is changed as a function of relative distance to the attentional focus: attention inside the cRF shrinks it, whereas directing attention next to the cRF expands it. In addition, we find systematic changes in surround inhibition and cRF amplitude. This nonmultiplicative push–pull modulation of the receptive field's center-surround structure optimizes processing at and near the attentional focus to strengthen the representation of the attended stimulus while reducing influences from distractors.

A Bayesian Spatial Multimarker Genetic Random‐Effect Model for Fine‐Scale Mapping

Multiple markers in linkage disequilibrium (LD) are usually used to localize the disease gene location. These markers may contribute to the disease etiology simultaneously. In contrast to the single-locus tests, we propose a genetic random effects model that accounts for the dependence between loci via their spatial structures. In this model, the locus-specific random effects measure not only the genetic disease risk, but also the correlations between markers. In other words, the model incorporates this relation in both mean and covariance structures, and the variance components play important roles. We consider two different settings for the spatial relations. The first is our proposal, relative distance function (RDF), which is intuitive in the sense that markers nearby are likely to correlate with each other. The second setting is a common exponential decay function (EDF). Under each setting, the inference of the genetic parameters is fully Bayesian with Markov chain Monte Carlo (MCMC) sampling. We demonstrate the validity and the utility of the proposed approach with two real datasets and simulation studies. The analyses show that the proposed model with either one of two spatial correlations performs better as compared with the single locus analysis. In addition, under the RDF model, a more precise estimate for the disease locus can be obtained even when the candidate markers are fairly dense. In all simulations, the inference under the true model provides unbiased estimates of the genetic parameters, and the model with the spatial correlation structure does lead to greater confidence interval coverage probabilities.

Attention reshapes center-surround receptive-field structure in Macaque cortical area MT

Event Abstract Back to Event Attention reshapes center-surround receptive-field structure in Macaque cortical area MT Katharina Anton-Erxleben1*, Valeska Stephan1 and Stefan Treue1 1 German Primate Center, Germany Directing spatial attention to a location inside the classical receptive field (cRF) of a neuron in macaque medial temporal area (MT) has been shown to shift the center of the cRF towards the attended location. Here we investigate the influence of spatial attention on the profile of the inhibitory surround present in many MT neurons. Two monkeys were trained to attend to the fixation point or to one of two random dot patterns (RDPs) placed at equal eccentricity inside or next to the cRF, while a third RDP (the probe) was briefly presented in quick succession at regularly spaced positions spanning the receptive field center and surround. Mean responses to probe presentation at the different positions were used to compute a map of the excitatory receptive field and its inhibitory surround. We find that attention systematically reshapes the receptive field profile, significantly and independently shifting both center and inhibitory surround towards the attended location. Furthermore, size of the cRF is changed as a function of relative distance of the attentional focus: attention inside the cRF shrinks it, while directing attention next to the cRF expands it. In addition, we find systematic changes in surround inhibition and cRF amplitude. This non-multiplicative push-pull modulation of the receptive field's center-surround structure by attention optimizes processing at and near the attentional focus to strengthen the representation of the attended stimulus while reducing influences from distractors. Conference: Bernstein Symposium 2008, Munich, Germany, 8 Oct - 10 Oct, 2008. Presentation Type: Poster Presentation Topic: All Abstracts Citation: Anton-Erxleben K, Stephan V and Treue S (2008). Attention reshapes center-surround receptive-field structure in Macaque cortical area MT. Front. Comput. Neurosci. Conference Abstract: Bernstein Symposium 2008. doi: 10.3389/conf.neuro.10.2008.01.024 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 13 Nov 2008; Published Online: 13 Nov 2008. * Correspondence: Katharina Anton-Erxleben, German Primate Center, Göttingen, Germany, k.antonerxleben@web.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Katharina Anton-Erxleben Valeska Stephan Stefan Treue Google Katharina Anton-Erxleben Valeska Stephan Stefan Treue Google Scholar Katharina Anton-Erxleben Valeska Stephan Stefan Treue PubMed Katharina Anton-Erxleben Valeska Stephan Stefan Treue Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Shock‐wave energy deflection due to the presence of bone

The physical interaction of shock waves with musculoskeletal tissues is inherently different from other high‐pressure acoustic therapies. Whereas high‐intensity focused ultrasound and lithotripsy focus their energy in regions of soft tissue, musculoskeletal shock‐wave therapy (SWT) involves focusing shock waves (SWs) near or at bones. The presence of bones will cause reflection, refraction, and diffraction of acoustic energy. In our analysis of cavitation generated during clinical SWT treatment, we noticed that the cavitation was occurring away from the SW focus. We confirmed this by performing an in‐vitro experiment on a bone embedded in gel. We also quantified the deflection angle as a function position near a bone in water: A talus was manufactured using rapid prototyping. It was placed near the focus of an electrohydraulic SW device. To visualize the pressure field, a high‐speed camera imaged the cavitation field generated around the focus. As the bone was moved closer to the focus, the cavitation field (and thus, the pressure field) deflected away from the bone. The deflection angle was measured as a function of relative distance between the bone and focus. Numerical simulations were performed to model the deflection of energy away from the bone.

A novel feedback method for optimizing the focus of an ultrafast photon source using the transient photocurrent of a high-speed device

A novel feedback method for focusing an ultrafast photon source is illustrated for the first time. The method relies on the pulse shape analysis (PSA) of the high-speed transient photocurrent (TP) measured as a function of relative distance between the objective lens and a photosensitive semiconductor device. Space-charge effects due to high-injection conditions result in a screened electron–hole pair plasma which exhibits an erosion time constant which depends on the density and ambipolar diffusivity of the plasma. Focusing the beam increases the average injection level thereby decreasing the ambipolar diffusivity and extending the transient photocurrent. A simple pulse shape analysis of the transient inside a feedback loop is used for optimizing the spot size. In theory, the method can be applied to any technique involving a photon source which delivers an ultrafast pulse which generates high-injection carrier levels when focused. Here, the method is outlined and demonstrated on a Si photodetector optimized for λ = 800 nm.

INTERACTION ENERGY IN MAYA-OIL ASPHALTENES: A MOLECULAR MECHANICS STUDY

The interaction energy in vacuum between large-scale (630 atom) Maya-oil asphaltenes and that for an asphaltene-resin dimer has been calculated using molecular mechanics for various relative orientations and distances, keeping a frozen-structure scheme. In the case of asphaltene-asphaltene interactions, it is found that the anti-aliphatic conformation (i.e., with the monomer alkyl branches far away from each other) with parallel well-defined aromatic regions constitutes the most stable structure for an asphaltene dimer. For the asphaltene-resin case, a set of stable configurations is found mainly associated with the exposed asphaltene aromatic regions. In this paper, a survey of the interaction energy for a particular asphaltene-resin configuration is reported and compared with the asphaltene-asphaltene case. The interaction energies as a function of relative distance are parameterized through an analytical expression distinguishing among Coulomb, dispersion, and London contributions. Finally, an effective-medium approach to estimate the effect of the embedding medium on the interaction energy is proposed through a dielectric scaling of the Coulomb and London contributions.

Skyrmions and their interactions using the Atiyah-Manton construction

The Atiyah-Manton (AM) construction based on instantons is used to construct skyrmions. For baryon number one, an analytic form for the skyrmion is obtained that compares well with the exact solution. For baryon number two, we study skyrmion interactions and distortion as a function of relative distance and orientation. From this we project out a nucleon-nucleon interaction. We find the principal features of the nuclear force but still no intermediate-range attraction. We compare the AM construction with the product ansatz.

Repetitions of Associations as a Function of Relative Distance between Successive Associates

This study of an hierarchical characteristic of associative strength was concerned with an associative factor of relative distance (RD) measured as distance from a primary associate to the secondary as referred to communality. Different stimulus lists varied RD by making the communality of primaries homogeneous and varying that of secondaries. The method of independent repetitions for successive trials of presentation of a stimulus was adopted, and the repetitive probability of associations and the latencies were measured. The RD directly reflected repetitions of associations, while among the lists of corresponding RD there was no difference in latency. Implications of the RD were discussed.

Relative Distance and Quasi-Conformal Mappings

1. Introduction. M. A. Lavrentiev made use of a relative distance function to establish some important results concerning the correspondence between the frontiers under a conformal mapping of a simply connected domain onto the unit circle. The purpose of this note is to show that some of these results are valid for the boundary correspondences induced by the more general class of quasi-conformal mappings.