7,421 research outputs found
Detailed Simulation of the Cochlea: Recent Progress Using Large Shared Memory Parallel Computers
We have developed and are refining a detailed three-dimensional computational model of the human cochlea. The model uses the immersed boundary method to calculate the fluid-structure interactions produced in response to incoming sound waves. An accurate cochlear geometry obtained from physical measurements is incorporated. The model includes a detailed and realistic description of the various elastic structures present. Initially, a macro-mechanical computational model was developed for execution on a CRAY T90 at the San Diego Supercomputing Center. This code was ported to the latest generation of shared memory high performance servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible to run several large scale numerical simulation experiments to study the interesting features of the cochlear system. In this paper, we outline the methods, algorithms and software tools that were used to implement and fine tune the code, and discuss some of the simulation results
Solar wind helium, neon and argon released by oxidation of metal grains from the Weston chondrite
A set of experiments were carried out to test the feasibility of determining unfractionated elemental and isotopic ratios for the noble gases in the presumably ancient solar wind present in the gas rich meteorites. The problems of diffusive loss was avoided by analyzing metal rather than the usual silicates. In order to avoid chemical, and even harsh physical, treatment of the sample, which might have affected the surfaces of metal grains, a means of analyzing the metal in the presence of residual silicate not removed by gentle crushing and magnetic separation was devised. Preliminary results given were obtained by taking advantage of the differing properties of metal and silicates with regard to diffusion. The results suggests that, with some modifications in the choice of pyrolysis and combustion temperatures and in the amount of O2 used, it should be possible, by oxidizing the surfaces of metal grains from gas rich meteorites, to obtain data on solar wind that has not been fractionated by diffusive loss
Lunar sample analysis
Results are presented from an extensive series of new high resolution scanning electron microscope studies of the very primative group of meteorites known as unequilibrated chondrites. These include quantitative analyses of micrometer sized phases and interpretation in terms of relevant phase equilibria. Several new meteorite minerals including high chromium metal, have been discovered
Challenges in video based object detection in maritime scenario using computer vision
This paper discusses the technical challenges in maritime image processing
and machine vision problems for video streams generated by cameras. Even well
documented problems of horizon detection and registration of frames in a video
are very challenging in maritime scenarios. More advanced problems of
background subtraction and object detection in video streams are very
challenging. Challenges arising from the dynamic nature of the background,
unavailability of static cues, presence of small objects at distant
backgrounds, illumination effects, all contribute to the challenges as
discussed here
AN EFFICIENT APPROACH FOR CONTENT BASED RETRIEVAL USING MULTI WAVELET AND HSV COLOR SPACE
This paper presents an approach for image retrieval by using multiwavelet and hsv color space. The HSV stands for the Hue, Saturation and Value, provides the perception representation according with human visual feature. The multiwavelets offer simultaneous orthogonality, symmetry and short support. In this paper, we have tested 140 images with 5 different categories. the experimental results show the better results interms of retrieval accuracy and computation complexity. The performance of this approach is measured and results are shown. Euclidean Distance and Canberra Distance are used as similarity measure in the proposed CBIR system
Neomercantilism and great-power energy competition in Central Asia and the Caspian.
The neomercantilist energy policies of China and Russia contribute to what is largely a competitive relationship among all three great powers in Central Asia. While neomercantilist policies do not negate the possibility of cooperation and the development of norms, rules, and institutions designed to promote collective action, they certainly erect formidable barriers
Spatiotemporal Cluster Analysis of Gridded Temperature Data -- A Comparison Between K-means and MiSTIC
The Earth is a system of numerous interconnected spheres, such as the
climate. Climate's global and regional influence requires understanding its
evolution in space and time to improve knowledge and forecasts. Analyzing and
studying decades of climate data is a data mining challenge. Cluster analysis
minimizes data volumes and analyzes behavior by cluster. Understanding
invariant behavior is as crucial as understanding variable behavior. Gridded
data from two sources: Grided IMD data and CMIP5 HadCM3 decadal experiments,
are studied using K-Means and MiSTIC clustering techniques to explore
spatiotemporal clustering of maximum and minimum temperatures. The boundaries
of k-means clustering correspond with topography. The Indian subcontinent's
physiographic, climatic, and topographical characteristics affect MiSTIC's core
areas. Both techniques yield overlapping clusters. The datasets' MiSTIC cluster
counts varied significantly. The impact of data on this technique is shown in
how the datasets group the Himalayas.Comment: 6 pages, 7 figures, Published with International Journal of
Scientific Research and Engineering Development - Volume 6 Issue
Group Norms and Consumer Behaviour
The impact of group norms on forming consumer behaviour is an important attribute of man’s social life. The market segmentation principles acknowledge the presence of this phenomenon. People belong to different age group, professional status, income levels, educational status etc. are seemed to display some specific consumer behaviour that can be attributed to a particular group. The present study attempts to find the influence of certain selected group norms on consumption pattern.Group norms, peer influence, consumer behaviour, culture and consumption, social norms
Adaptive Importance Sampling for Performance Evaluation and Parameter Optimization of Communication Systems
We present new adaptive importance sampling techniques based on stochastic Newton recursions. Their applicability to the performance evaluation of communication systems is studied. Besides bit-error rate (BER) estimation, the techniques are used for system parameter optimization. Two system models that are analytically tractable are employed to demonstrate the validity of the techniques. As an application to situations that are analytically intractable and numerically intensive, the influence of crosstalk in a wavelength-division multiplexing (WDM) crossconnect is assessed. In order to consider a realistic system model, optimal setting of thresholds in the detector is carried out while estimating error rate performances. Resulting BER estimates indicate that the tolerable crosstalk levels are significantly higher than predicted in the literature. This finding has a strong impact on the design of WDM networks. Power penalties induced by the addition of channels can also be accurately predicted in short run-time
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