Showing papers by "Gaurav Sharma published in 2008"

On the security and robustness of encryption via compressed sensing

Abstract: The compressed sensing (CS) paradigm unifies sensing and compression of sparse signals in a simple linear measurement step. Reconstruction of the signal from the CS measurements relies on the knowledge of the measurement matrix used for sensing. Generation of the pseudo-random sensing matrix utilizing a cryptographic key, offers a natural method for encrypting the signal during CS. This CS based encryption has the inherent advantage that encryption occurs implicitly in the sensing process - without requiring additional computation. Additionally, the robustness of recovery from compressed sensing, allows a new form of ldquorobust encryptionrdquo for multimedia data, wherein the signal is recoverable with high fidelity despite the introduction of additive noise in the encrypted data. In this paper, we examine the security and robustness of this CS based encryption method. The security implications are investigated by considering brute force and structured attacks. Robustness is characterized empirically. Our analysis and results indicate that the computational complexity of these attacks renders them infeasible in practice. In addition, the CS based encryption is found to have fair robustness against additive noise, making it a promising ldquorobust encryptionrdquo technique for multimedia.

A case for hybrid sensor networks

Abstract: In this paper, we investigate the use of limited infrastructure, in the form of wires, for improving the energy efficiency of a wireless sensor network. We call such a sensor network - a wireless sensor network with a limited infrastructural support - a hybrid sensor network. The wires act as short cuts to bring down the average hop count of the network, resulting in a reduced energy dissipation per node. Our results indicate that adding a few wires to a wireless sensor network can not only reduce the average energy expenditure per sensor node, but also the non-uniformity in the energy expenditure across the sensor nodes.

Design and development of a multi-die embedded micro wafer level package

Abstract: The primary trend in electronics industry is product miniaturization Both design and manufacturing engineers are looking for ways to make products lighter, smaller, less expensive, and at the same time faster, more powerful, reliable, user-friendly, and functional A partial list of today's "shrinking" products would include cellular phones, personal and sub-notebook computers, pagers, PCMCIA cards, camcorders, palmtop organizers, telecommunications equipment, and automotive components With silicon chips continue integrating more functionality as per Moore's law, the packaging is challenged to integrate and shrink Chips first or embedded chip packaging is a revolutionary way to overcome these recent packaging integration challenges Packaging researchers have worked on embedded packaging and developed newer way of embedding the chip The PBGA replaced the lead frame based peripheral array packages, in which the die is electrically connected to circuit board (PCB) substrate by wire bonding or flip chip technology, before covering with molding compound Embedded Wafer level packaging takes the next step, eliminating the PCB, as well as the need to use wire bonding or flip-chip bumps to establish electrical connection This paper deals with the development embedding multiple dies at wafer level A detailed mechanical and structural analysis of the package in terms of the die thickness, wafer size and warpage is presented The package format is suitable for stacking multiple die in 3D format and 2D format The paper also deals with characterization of the materials and the process integration of the multidie wafer level packaging Initial reliability results of the package are also presented

Insertion, Deletion Codes With Feature-Based Embedding: A New Paradigm for Watermark Synchronization With Applications to Speech Watermarking

Abstract: A framework is proposed for synchronization in feature-based data embedding systems that is tolerant of errors in estimated features. The method combines feature-based embedding with codes capable of simultaneous synchronization and error correction, thereby allowing recovery from both desynchronization caused by feature estimation discrepancies between the embedder and receiver; and alterations in estimated symbols arising from other channel perturbations. A speech watermark is presented that constitutes a realization of the framework for 1-D signals. The speech watermark employs pitch modification for data embedding and Davey and Mackay's insertion, deletion, and substitution (IDS) codes for synchronization and error recovery. Experimental results demonstrate that the system indeed allows watermark data recovery, despite feature desynchronization. The performance of the speech watermark is optimized by estimating the channel parameters required for the IDS decoding at the receiver via the expectation-maximization algorithm. In addition, acceptable watermark power levels (i.e., the range of pitch modification that is perceptually tolerable) are determined from psychophysical tests. The proposed watermark demonstrates robustness to low-bit-rate speech coding channels (Global System for Mobile Communications at 13 kb/s and AMR at 5.1 kb/s), which have posed a serious challenge for prior speech watermarks. Thus, the watermark presented in this paper not only highlights the utility of the proposed framework but also represents a significant advance in speech watermarking. Issues in extending the proposed framework to 2-D and 3-D signals and different application scenarios are identified.

PARTS: Probabilistic Alignment for RNA joinT Secondary structure prediction

Abstract: A novel method is presented for joint prediction of alignment and common secondary structures of two RNA sequences. The joint consideration of common secondary structures and alignment is accomplished by structural alignment over a search space defined by the newly introduced motif called matched helical regions. The matched helical region formulation generalizes previously employed constraints for structural alignment and thereby better accommodates the structural variability within RNA families. A probabilistic model based on pseudo free energies obtained from precomputed base pairing and alignment probabilities is utilized for scoring structural alignments. Maximum a posteriori (MAP) common secondary structures, sequence alignment and joint posterior probabilities of base pairing are obtained from the model via a dynamic programming algorithm called PARTS. The advantage of the more general structural alignment of PARTS is seen in secondary structure predictions for the RNase P family. For this family, the PARTS MAP predictions of secondary structures and alignment perform significantly better than prior methods that utilize a more restrictive structural alignment model. For the tRNA and 5S rRNA families, the richer structural alignment model of PARTS does not offer a benefit and the method therefore performs comparably with existing alternatives. For all RNA families studied, the posterior probability estimates obtained from PARTS offer an improvement over posterior probability estimates from a single sequence prediction. When considering the base pairings predicted over a threshold value of confidence, the combination of sensitivity and positive predictive value is superior for PARTS than for the single sequence prediction. PARTS source code is available for download under the GNU public license at http://rna.urmc.rochester.edu.

Antidiabetic activity of a polyherbal formulation (DRF/AY/5001).

Abstract: The herbal formulation, DRF/AY/5001, elicits hypoglycemic/antidiabetic effects in both normal and experimentally induced hyperglycemic (epinephrine and alloxan) rats. Further, herbal formulation treatment can significantly alter the pattern of glucose tolerance in normal and diabetic rats. It is possible that the herbal formulation may act through both, pancreatic and extra-pancreatic mechanism(s). The DRF/AY/5001 also elicited a significant antioxidant effect in alloxan diabetic rats as reflected by its ability to inhibit lipid peroxidation and to elevate the enzymatic antioxidants in pancreatic tissue. The histopathological studies during the long term treatment have shown to ameliorate the alloxan induced histological damage of islets of Langerhans. The inhibitory effects on biochemical and histological parameters induced by herbal formulation at a dose of 600 mg/kg were almost comparable to that of standard drug, glibenclamide (4 mg/kg). The present study demonstrates that herbal formulation exhibits promisisng antidiabetic activity and helps to maintain good glycemic and metabolic control.

Network tomography via network coding

Abstract: In this work we show how existing network coding algorithms can be used to perform network tomography, i.e., estimate network topology. We first examine a simple variant of the popular distributed random network codes proposed by (Ho et al.) and show how it can enable each network node to passively estimate the network topology upstream of it at no cost to throughput. The delays introduced by each upstream node and link can also be similarly estimated. We then consider the scenario wherein an adversary hidden in the network wishes to disrupt the estimation of network topology. We show how network error-correcting codes can be used to reliably perform network tomography if the network has sufficient connectivity, and demonstrate that network tomography is impossible otherwise.

Data embedding in hardcopy images via halftone-dot orientation modulation

Abstract: The principal challenge in hardcopy data hiding is achieving robustness to the print-scan process. Conventional robust hiding schemes are not well-suited because they do not adapt to the print-scan distortion channel, and hence are fundamentally limited in a detection theoretic sense. We consider data embedding in images printed with clustered dot halftones. The input to the print-scan channel in this scenario is a binary halftone image, and hence the distortions are also intimately tied to the nature of the halftoning algorithm employed. We propose a new framework for hardcopy data hiding based on halftone dot orientation modulation. We develop analytic halftone threshold functions that generate elliptically shaped halftone dots in any desired orientation. Our hiding strategy then embeds a binary symbol as a particular choice of the orientation. The orientation is identified at the decoder via statistically motivated moments following appropriate global and local synchronization to adress the geometric distortion introduced by the print scan channel. A probabilistic model of the print-scan process, which conditions received moments on input orientation, allows for Maximum Likelihood (ML) optimal decoding. Our method bears similarities to the paradigms of informed coding and QIM, but also makes departures from classical results in that constant and smooth image areas are better suited for embedding via our scheme as opposed to busy or "high entropy" regions. Data extraction is automatically done from a scanned hardcopy, and results indicate significantly higher embedding rate than existing methods, a majority of which rely on visual or manual detection.

Encoding message data in a cover contone image via halftone dot orientation

Abstract: What is disclosed is a novel system and method for encoding/decoding data in a cover contone image via halftone dot orientation modulation. Arrays of halftone threshold values are used to determine a desired orientation, e.g. 0/90°+/−45° for a given single data value of the original message to be embedded. Message data is embedded as a function of halftone dot orientation. Detection modeling of the print-scan process enables the determination of dot orientation from the image scan via statistically motivated image moments. A probabilistic model of the print-scan channel conditions received moments on input orientation. Density values of the received moments are used to determine dot orientation for each halftone cell. The embedded data is retrieved based on the determined orientations. The present method is applicable to areas of data embedding, document security, and the like.

Die package and a method for manufacturing the die package

Abstract: A die package and a method for manufacturing the die package are provided. The die package includes a second die arranged above a first die, the first die comprising an interconnect region on a surface facing the second die, wherein the second die is arranged laterally next to the interconnect region of the first die; a first package-internal free-standing interconnect structure disposed above the interconnect region of the first die; a second package-internal free-standing interconnect structure disposed above an interconnect region of the second die, the interconnect region of the second die being on a surface of the second die facing away from the first die; and package material formed partially around the first package-internal free-standing interconnect structure and the second package-internal free-standing interconnect structure such that a connecting portion of the first package-internal free-standing interconnect structure and a connecting portion of the second package-internal free-standing interconnect structure remains uncovered to be electrically connected to a package-external interconnect structure.

Misregistration sensitivity in clustered-dot color halftones

Abstract: Halftoned separations of individual colorants, typically cyan, magenta, yellow, and black, are overlaid on a print substrate in typical color printing systems. Displacements between these separations, commonly referred to as "interseparation misregistra- tion", can cause objectionable color shifts in the prints. We study this misregistration-induced color shift for periodic clustered-dot half- tones using a spatiospectral model for the printed output that com- bines the Neugebauer model with a periodic lattice representation for the individual halftones. Using Fourier analysis in the framework of this model, we obtain an analytic characterization for the condi- tions for misregistration invariance in terms of colorant spectra, pe- riodicity of the individual separation halftones, dot shapes, and mis- registration displacements. We further exploit the framework in a hybrid analytical-numerical simulation that allows us to obtain quan- titative estimates of the color shifts due to misregistration, thereby providing a characterization for these shifts as a function of the op- tical dot gain, halftone periodicities, spot shapes, and intersepara- tion misregistration amounts. We present simulation results that demonstrate the impact of each of these parameters on the color shift and demonstrate qualitative agreement between our approxi- mation and experimental data. © 2008 SPIE and IS&T.

'Induction of inflammatory gene expression by THP-1 macrophages cultured in normocholesterolaemic hypertensive sera and modulatory effects of green tea polyphenols'.

Abstract: Hypertension is a disorder controlled by multiple genes and inflammation and vascular remodelling of arteries have been implicated in pathogenesis of this disease. Green tea polyphenols (GrTPs) are rich in antioxidants and are known to inhibit inflammatory responses. A significant time-dependent increase in mRNA expression of both IL-6 and MMP-9 were observed in THP-1 macrophages when cultured in normocholesterolaemic hypertensive sera (P<0.05).

Preprocessing Methods for Improved Lossless Compression of Color Look-up Tables

Abstract: Color look-up tables (CLUTs) that provide transforma- tions between various color spaces are commonly embedded in printer firmware where they are stored in relatively expensive flash memory. As the number of look-up tables in color devices increases in size, the space requirements of storing these CLUTs also in- crease. In order to conserve memory and thereby reduce cost, it is desirable to compress CLUTs prior to storage and restore tables as required. We consider methods for improving the performance of existing lossless compression methods for this application through computationally simple preprocessing. The preprocessing combines predictive coding and data reordering to better exploit the redun- dancy in CLUT data. Two predictive coding methods are consid- ered: (a) hierarchical differential encoding methods, which general- izes differential coding to multiple dimensions, and (b) cellular interpolative predictive coding, which refines a CLUT in a coarse to fine order using interpolative prediction. Space filling curves that preserve continuity in the multidimensional CLUT structure are uti- lized for reordering the residuals obtained from hierarchical differen- tial encoding. For the cellular interpolative prediction, we reorder the data in the coarse to fine order utilized for prediction. Results indi- cate that the proposed preprocessing methods offer significant per- formance improvements in comparison with direct compression. The best performance is obtained using the cellular interpolative predictive coding and corresponding reordering with the LZMA algo- rithm. This method provides a compression ratio of 3.19 over our representative CLUT data set, and an improvement of 31.33% over direct LZMA compression, the latter being the best performing direct method. © 2008 Society for Imaging Science and Technology. DOI: 10.2352/J.ImagingSci.Technol.200852:4040901

Decoding message data embedded in an image print via halftone dot orientation

Abstract: What is disclosed is a novel system and method for encoding/decoding data in a cover contone image via halftone dot orientation modulation. Arrays of halftone threshold values are used to determine a desired orientation, e.g. 0/90°+/−45° for a given single data value of the original message to be embedded. Message data is embedded as a function of halftone dot orientation. Detection modeling of the print-scan process enables the determination of dot orientation from the image scan via statistically motivated image moments. A probabilistic model of the print-scan channel conditions received moments on input orientation. Density values of the received moments are used to determine dot orientation for each halftone cell. The embedded data is retrieved based on the determined orientations. The present method is applicable to areas of data embedding, document security, and the like.

Lossless compression of color look-up table via hierarchical differential encoding or cellular interpolative prediction

Abstract: A color look-up table (CLUT) is compressed in a lossless manner. The CLUT includes nodes that convert values of a first color space to corresponding values of a second color space. The CLUT is received in a serialized node-by-node manner. For each of some of the nodes, the following is performed in the order in which the nodes are received in the serialized node-by-node manner. First, a difference value is determined that represents compression of a value of the node, in accordance with a hierarchical differential encoding approach or in accordance with a cellular interpolative prediction approach. Second, the difference value is stored in lieu of the value of the node being stored, to compress the value of the node in the lossless manner.

Determination of age from pubic symphysis: an autopsy study.

Abstract: The present study was conducted on three hundred and thirty-six cases brought for autopsy to the Department of Forensic Medicine, Government Medical College, Amritsar, Punjab, India, during the period 2000-2002. Pubic bones of either sex were analysed according to Todd's method (1920; 1921a,b,c) as modified by McKern and Stewart (1957) to assess and compare the known age of the corpses. Cases belonged to both sexes, i.e. 79.46% males and 20.54% females. All the cases were above the age of 17 years. No difference was noted in the scoring of right and left pubic bones. The age estimation from different components in males and females up to the total score of 10 (23-28 years) was +/- 6, whereas above a score of 10 the estimated age was +/- 12 in males and +/- 9 in females. The age range given for scores of 14 and 15, which were 29+ and 36+ respectively, did not account for variability of age after 40 years. Therefore, the age assessment from pubic bones in the fourth decade age group and beyond is not reliable which is in variance to the study by McKern and Stewart (1957).

Reversible pH-controlled DNA-binding peptide nanotweezers: an in-silico study.

Abstract: We describe the molecular dynamics (MD)-aided engineering design of mutant peptides based on the α-helical coiled-coil GCN4 leucine zipper peptide (GCN4-p1) in order to obtain environmentally-responsive nanotweezers. The actuation mechanism of the nanotweezers depends on the modification of electrostatic charges on the residues along the length of the coiled coil. Modulating the solution pH between neutral and acidic values results in the reversible movement of helices toward and away from each other and creates a complete closed-open-closed transition cycle between the helices. Our results indicate that the mutants show a reversible opening of up to 15 A (1.5 nm; approximately 150% of the initial separation) upon pH actuation. Investigation on the physicochemical phenomena that influence conformational properties, structural stability, and reversibility of the coiled-coil peptide-based nanotweezers revealed that a rationale- and design-based approach is needed to engineer stable peptide or macromolecules into stimuli-responsive devices. The efficacy of the mutant that demonstrated the most significant reversible actuation for environmentally responsive modulation of DNA-binding activity was also demonstrated. Our results have significant implications in bioseparations and in the engineering of novel transcription factors.

Adaptive decoding for halftone orientation-based data hiding

Abstract: Halftone image watermarking techniques that allow automated extraction of the embedded watermark data are useful in a variety of document security and workflow applications. The print-scan process inherent in these applications introduces distortions whose characteristics exhibit a strong spatial dependence on the cover image in which the data is embedded. In this paper, we demonstrate that a characterization of this channel dependence and the use of error correction coding that exploits this dependence via image adaptive decoding offers a significant performance gain. We show this advantage in the specific context of a high rate data embedding method that utilizes orientation modulation for data embedding in clustered dot halftones and moment based detection at the receiver. Channel coding for this scenario utilizing convolutional codes and Repeat Accumulate (RA) codes highlights the advantage of the proposed adaptive decoding methodology. The performance for the RA codes with adaptive decoding also reveals that the resulting system has significantly higher operational rates than prior schemes.

Steganalysis-aware steganography: statistical indistinguishability despite high distortion

Abstract: We consider the interplay between steganographer and the steganalyzer, and develop a steganalysis aware framework for steganography. The problem of determining a stego image is posed as a feasibility problem subject to constraint of data communication, imperceptibility, and statistical indistinguishability with respect to steganalyzer's features. A stego image is then determined using set theoretic feasible point estimation methods. The proposed framework is applied effectively on a state of the art steganalysis method based on higher order statistics (HOS) steganalysis. We first show that the steganographer can significantly reduce the classification performance of the steganalyzer by employing a statistical constraint during embedding, although the image is highly distorted. Then we show that steganalyzer can develop a counter-strategy against steganographer's action, gaining back some classification performance. This interchange represents an empirical iteration in this game between the steganographer and steganalyzer. Finally we consider mixture strategies to find the Nash equilibrium of the interplay.

Clustered-Dot Color HalftoneWatermarks.

Abstract: Spatial frequency separability is proposed as an attractive exploit for obtaining color halftone watermarking methods from monochrome clustered-dot halftone watermarking techniques. Detection of watermarks embedded in individual halftone channels is typically confounded by the cross-coupling between colorant halftone separations and scan RGB channels caused by the so-called “unwanted absorptions”. This problem is resolved in the proposed framework by utilizing spatial filtering in order to obtain estimates of individual separation halftones that are suitable for watermark detection. The effectiveness of this methodology is experimentally demonstrated by utilizing continuous phase modulation for per-separation watermark embedding. The embedded watermark patterns in the halftone separations can be clearly detected from scans using the proposed spatial separability exploit. Continuous phase modulation based per-channel embedding with detection following spatial-filtering based separation thus provides an effective watermarking method for clustered-dot color halftones.

Biodiversity of lepidopterous insects associated with vegetables in India – A study

Abstract: One hundred and fifty four localities covering fourteen states/union territories were explored through intensive and extensive surveys during 2003–07. Thirty one states/union territories were covered on the basis of collected/reference specimens of lepidopterous insects associated with vegetables in India studied in the National Pusa Collection, Division of Entomology, Indian Agricultural Research Institute, New Delhi. About 738 specimens belonging to 18 families under 11 superfamilies of order Lepidoptera had been collected from the field and 22 crops of vegetables were covered. A checklist prepared on lepidopterous insects associated with vegetables in India reveals that it comprises 152 species under 25 families and 14 superfamilies 110 species belonging to 21 families and 11 superfamilies were recorded in the present study. The observations reveal that the major superfamilies are Noctuoidea (62 species; 40.67%) and Pyraloidea (30 species; 19.33%); major families include Noctuidae (37 species; 24.34%) and Crambidae (25 species; 16.45%). The investigations on the nature of damage reveal that 40.79% are leaf feeders, 8.55% are pod borers, 7.89% each are fruit borers, defoliators and leaf rollers, 5.26% each are bud borers and leaf webbers, and 4.61% each are cut worms, leaf miners and stem borers. The salient details of their hosts, pest status or otherwise and their updated names and classification are provided.

Fluoroboric Acid Adsorbed on Silica‐Gel (HBF4—SiO2) as a New, Highly Efficient and Reusable Heterogeneous Catalyst for thia‐Michael Addition to α,β‐Unsaturated Carbonyl Compounds.

Abstract: Fluoroboric acid adsorbed on silica-gel (HBF 4 –SiO 2 ) has been found to be a new and highly efficient heterogeneous catalyst for thia-Michael addition to α,β-unsaturated carbonyl compounds under solvent-free conditions. In the case of 1,3-diaryl-2-propenones, the reactions are best carried out in MeOH. The rate of thia-Michael addition was dependent on the steric hindrance at the β-carbon of the α,β-unsaturated carbonyl substrate as well as surrounding the thiol moiety and was exploited for selective thia-Michael addition during intermolecular competition between two enones with a common thiol and between two aryl/alkyl thiols for a common enone. The methodology finds application for one-pot syntheses of 2,3-dihydro-1,5-benzothiazepines.