Showing papers by "Gaurav Sharma published in 2004"

Scaling laws for capacity and delay in wireless ad hoc networks with random mobility

Abstract: We study the asymptotic throughput capacity and delay in mobile ad hoc networks following the 2-hop relaying algorithm proposed by Grossglauser and Tse (2001). We assume the nodes to be uniformly distributed on a sphere, and consider two canonical mobility models: the Brownian mobility model (BMM), and the random way-point mobility model (RWMM). We show that for an ad hoc network formed by n mobile nodes the delay scales as O (log/sup 2/n//spl sigma//sup 2/(n)) under the BMM, and, /spl Theta/ (1/r(n)v(n)) under the RWMM, where /spl sigma//sup 2/(n) is the variance parameter of the BMM, v(n) is the average speed of nodes under the RWMM, and r(n) is the communication radius of the nodes.

Method for scanner characterization for color measurement of printed media having four or more colorants

Abstract: The present invention is directed to a method and apparatus for the improved characterization of an image scanner or similar image input terminal so as to enable the device to be employed in the measurement and analysis of color images. The invention uses a family of input device characterization targets, each varying in primary colorants and at a fixed level of black (K) colorant. A corresponding family of input device characterizations is derived, one for each level of K, and the final transformation is prepared such that the characterization includes K as an additional input—thereby improving the characterization and accuracy of the input device.

Current trends of poisoning – A hospital profile

Abstract: The paper relates to one year study of poisoning cases who were admitted in the Emergency wing of Guru Nanak Dev Hospital attached to Govt. Medical College, Amritsar w.e.f. 10-5-1997 to 9.5.1998. Out of 10664 admitted emergencies, poisoning was diagnosed in 3.19% of cases. Male female ratio was nearly 3: 1. Majority of the victims were in the age group of 21–30 years (45.59%), 69.12% were married and 51.47% belonged to urban area. At the time of admission 61.47% cases were conscious, 26.17% were partially conscious and 12.36% were unconscious. Majority (76.46%) of victims committed suicide, in 20.91 % cases manner of death was accident and homicide was reported in minimal (1.76%) cases. Commonest poison used was aluminium phosphide (38.23%) and next was organo-phosphorous compounds (17.64%). The study observed increasing trend of suicide by Aluminium phosphide and organo phosphorous compound, where as other poisons for committing suicide are less commonly used.

Collusion-resilient fingerprinting by random pre-warping

Abstract: Fingerprinting of audio-visual content using digital watermarks is an effective means of determining originators of unauthorized/pirated copies. Watermarks embedded in content can trace the traitor responsible for piracy. Multiple users may, however, collude and collectively escape identification by creating an average of their individually watermarked copies that appears unwatermarked. We propose a novel collusion-resilience mechanism, wherein the host signal is warped randomly prior to watermarking. As each copy undergoes a distinctive warp, collusion through averaging either yields low-quality results or requires substantial computational resources to undo random warps. The method is independent of the watermarking scheme used and imposes no restrictions on the watermark signal. We demonstrate the effectiveness of this approach on digital images.

Universal Image Steganalysis Using Rate-Distortion Curves

Abstract: The goal of image steganography is to embed information in a cover image using modifications that are undetectable. In actual practice, however, most techniques produce stego images that are perceptually identical to the cover images but exhibit statistical irregularities that distinguish them from cover images. Statistical steganalysis exploits these irregularities in order to provide the best discrimination between cover and stego images. In general, the process utilizes a heuristically chosen feature set along with a classifier trained on suitable data sets. In this paper, we propose an alternative feature set for steganalysis based on rate-distortion characteristics of images. Our features are based on two key observations: i) data hiding methods typically increase the image entropy in order to encode hidden messages; ii) data hiding methods are limited to the set of small, imperceptible distortions. The proposed feature set is used as the basis of a steganalysis algorithm and its performance is investigated using different data hiding methods.

Method and system for classifying scanned-media

Abstract: A method for automatically classifying a printed image, includes scanning the printed image; selecting an n by n block of pixels from the scanned image; calculating an array of DCT coefficients of the pixel block, wherein the array of calculated DCT coefficients are representative of spatial frequency and spatial orientation of the pixel block; comparing the DCT coefficients with an array of predetermined values, wherein the array of predetermined values are indicative of different image marking processes used to produce printed images; and determining an image marking process used to create the printed image based on the comparison of the DCT coefficients with the array of predetermined values. The array of DCT coefficients may be sampled into a feature set and the feature set provided to a neural network to output the determined image marking process.

Synthesis, characterization, and magnetic properties of FeCoNi ternary alloy nanowire arrays

Abstract: FeCoNi ternary alloy nanowire arrays 32–106 nm in diameter were fabricated within nanoporous alumina membranes using 15 Vrms alternating current electrodeposition at frequencies of 50, 250, 500, 750, and 1000 Hz. The magnetic coercivity and hysteresis loop squareness-ratio (Mr/Ms) were studied as functions of electrolyte composition, nanowire diameter, and nanowire aspect ratio.

Mathematical Discontinuities in CIEDE2000 Color Difference Computations.

Abstract: We examine mathematical properties of the CIEDE2000 color difference formula and illustrate that the CIEDE2000 color difference is not a continuous function of the CIELAB color pairs between which the difference is calculated. Particularly, we illustrate that ambiguities in the computation of mean hue angle and hue angle differences of color pairs contribute to a discontinuity in the formula for color pairs chosen 180-degrees apart in CIELAB hue. We analyze and characterize the discontinuity and give a visual presentation that allows better appreciation of its nature. For color pairs under 5 CIELAB delta E units apart, the maximum discontinuity magnitude is bounded by 0.274. For color pairs further apart in CIELAB, the magnitude of the discontinuity rises sharply. The results indicate that care should be exercised in using the formula in Taylor series approximations and that its use should be restricted to small color differences as recommended by the CIEDE2000 standard.

Systems and methods for estimating an image marking process using scanned image attributes

Abstract: Methods and systems used to automatically identify the marking process used for an image on a substrate based on spatial characteristics and/or color of the image. Image types which are classified and identified include continuous tone images and halftone images. Among halftone images separately identified are inkjet images, xerographic images and lithographic images. Locally adaptive image threshold techniques may be used to determine the spatial characteristics of the image.

Method and apparatus for adjusting color profiles to meet a desired aim

Abstract: A system and method for generating an adjusted profile for a device in response to a specified aim, where the aim may include parameters established in response to a user's specifications, for device emulation, etc.

Synthesis and characterization of extremely uniform Fe-Co-Ni ternary alloy nanowire arrays.

Abstract: We have fabricated extremely uniform arrays of polycrystalline Fe-Co-Ni ternary alloy nanowires having composition Fe 12.3 wt.%, Co 43.9 wt.% and Ni 43.8 wt.%. The wires are made by electrodeposition into nanoporous alumina templates, using an electrodeposition voltage of 15 V at 1000 Hz. Nanowires have been fabricated having diameters ranging from 43 nm to 120 nm, and lengths of 3 microm to 7 microm, as dependent upon template topology. The magnetization easy axis lies along the nanowire length, with an easy axis coercivity of 72 kA/m.

WEED MANAGEMENT IN POTATO-tUNDER DRY TEMPERATE AGRO- ECOSYSTEM (HP)

Abstract: Field experiments were carried out to assess the efficacy of different herbicides on potato from 1996 to 1998 at Highland Agricultural Research and Extension Centre, Kukumseri (HP). Atrazine and pendimethalin were more effective on broadleaf weeds whereas alachlor, metolachlor and isoproturon were more effective on grassy weeds. Pre-emergence application of metolachlor 1.5 kg/ha recorded the highest tuber yield (265.9 q/ha) which was at par with atrazine 0.0-1.25 kg/hal, isoproturon (1.25-1.5 kg/ha), alachlor 1.5 kg/ha, pendimethalin 1.2 kg/ha and fluchloralin 1.35 kg/ha. Application of atrazine 1.25 kg/ha, isoproturon (1.25-1.5 kglha), metolachlor 1.5 kg/ha and pendimethalin 1.2 kg/ha proved significantly better than twice hand weeding and hoeing. Uncontrolled weed growth caused 55.3, 47.2 and 45.7 per cent reduction in tuber yield as compared to the application of metolachlor 1.5 kg/ha, hand weeding twice and farmers' practice, respectively.

Efficient classification of scanned media using spatial statistics

Abstract: We address the automatic classification of scanned input media in order to improve color calibration. Since scanner responses vary significantly according to the type of input, a media dependent color calibration for a scanner is desirable for accurately mapping scanner responses to a standard color space. To assist such media dependent calibration, we propose an efficient algorithm for automated classification of input media into four major classes corresponding to photographic, lithographic, xerographic and inkjet. Our technique exploits the strong correlation between the type of input medium and the spatial statistics of corresponding images, which may be observed in the scanned images. Adopting two spatial statistical measures of dispersion and periodicity and utilizing extensive training data, we determine well separated decision regions to classify the input medium with a high confidence level. Experimental results over an independent test data set validate the results.

Stochastic screens robust to mis-registration in multi-pass printing

Abstract: A new technique for design of stochastic screens is proposed that produces screens that are robust against mis-registration in multi-pass printing. Conventional stochastic screens are designed through an optimization process that minimizes low-frequency structure in halftone images under the assumption that the placement of pixels is accurate. In inkjet printing, however, a page is often printed in multiple passes to allow for better drying of inks and to minimize appearance of a head signature. Any potential mis-registration between the passes is typically not comprehended in the conventional stochastic screen design process. The mis-registration between the passes can therefore cause significantly increased graininess (low-frequency structure) in printed images produced with stochastic screens even though the corresponding electronic bitmaps are free from low-frequency structure. In this paper, we propose modifications to the stochastic screen design process that take the two pass printing into account and produce halftones that are robust to inter-pass mis-registration errors. This allows reduced tolerances and alignment requirements in manufacturing that translate to lower cost. The proposed technique works by modifying the screen design process to ensure that a majority of the minority pixels are concentrated in a single pass, which provides improved robustness to mis-registration between the passes. Experimental results demonstrate that the proposed design technique performs significantly better than conventional stochastic screens in the presence of mis-registration errors.

Effect of Weed Management and Fertility Levels on Rajmash (Phaseolus vulgaris) and Associated Weeds under Dry Temperate High Hills in Himachal Pradesh

Abstract: Field experiment was conducted during the summer of 1999 and 2000 at Kukumseri (2872 m above msl) on sandy loam soil to find out viable fertility level in relation to weed control in rajmash. All the herbicide treatments being statistically at par among themselves produced significantly lower weed number and dry matter, thus resulting in significantly higher seed yield of rajmash over weedy check. The minimum weed number and dry matter accumulation were recorded following the application of pendimethalin 0.9 kg+alachlor 0.75 kg ha−1 and resulted in weed control efficiency of 71.7% as compared to weedy check. This was followed by alachlor 1.5 kg ha−1 and pendimethalin 1.2 kg ha−1. The highest benefit: cost ratio was resulted following the application of alachlor at 1.50 kg ha−1. Weed population was not influenced by increase in fertility levels. Significantly highest weed biomass was recorded when crop was fertilized with 150% of recommended fertility level (40 kg N, 60 kg P2O5 and 30 kg K2O ha−1). Increase in fertility level did not bring significant increase in the yield attributes and grain yield. The benefit: cost ratio was highest (5.14) following 100% recommended dose.

Spectral multiplexing of images to provide a composite image

Abstract: Methods and apparatus for spectrally-encoding plural source images and for providing the spectrally-encoded plural source images in a composite image, for rendering the composite image in a physical form, or for recovering at least one of the encoded source images from the rendered composite image such that the recovered source image is made distinguishable. Source image confusion in a rendered composite image is controlled by application of a illuminant-neutral gray component replacement (GCR) technique to the darkness common to the different colorants under the multiple illuminants.

Determinatio of age from teeth using index value of root translucency

Abstract: Study was conducted in LHMC & Associated Smt Sucheta Kriplani Hospital, New Delhi to estimate age from central maxillary incisor by calculating the index value of root translucency. Total number of cases studied was one hundred and fifty. The aims of the study were to evaluale the degree of root translucency as objectively as possible, neutralizing the role of oral pathology and its correlation with age.

System for spectral multiplexing and rendering and spectral inverted multiplexing source image for forming moving picture source image

Abstract: PROBLEM TO BE SOLVED: To provide one or a plurality of systems for spectral multiplexing a plurality of source images to supply a composite image, rendering the composite image and demultiplexing such a composite image to recover one or more source images. SOLUTION: A method for processing a plurality of source images comprises a stage for encoding the plurality of source images within a composite image, a stage for using a plurality of dyes for rendering the composite image on a base material, and a stage for recovering the encoded source images from the rendered composite image so as to make the recovered source images descernible by applying the lights of a plurality of narrow-band light emitters which are preselected to the rendered composite images so as to show respectively the relating source images. The sequence of switched light emitters quickly and continuously recovers the sequence of corresponding source images, that is, imparts a sense of motion. COPYRIGHT: (C)2004,JPO

Method of standardizing input cmyk value of clustered printing environment

Abstract: PROBLEM TO BE SOLVED: To perform control so that a printer has substantially the same output color response to substantially the same input CMYK values. SOLUTION: Pre-conversion among C, M, Y and K is carried out before at least one printer to be clustered and the conversion is so designed as to make it secure for a printer handled through the pre-conversion to have substantially the same output color for substantially the same input CMYK values. For example, a 3D LUT among C, M and K and a 1D LUT for K are generated by using sensors in a field. COPYRIGHT: (C)2006,JPO&NCIPI