2003 IEEE Wireless Communications and Networking, 2003. WCNC 2003., 2000
During the past few years, distributed wireless sensor networks have been the focus of considerab... more During the past few years, distributed wireless sensor networks have been the focus of considerable research for both military and civil applications. Sensors are generally constrained in on-board energy supply therefore efficient management of the network is crucial to extend the life of the system. Sensors' energy cannot support long haul communication to reach a remote command site, thus they require multi-tier architecture to forward data. An efficient way to enhance the lifetime of the system is to partition the network into distinct clusters with a high-energy node called gateway as cluster-head. Failures are inevitable in sensor networks due to the inhospitable environment and unattended deployment. However, failures in higher level of hierarchy e.g. cluster-head cause more damage to the system because they also limit accessibility to the nodes that are under their supervision. In this paper we propose an efficient mechanism to recover sensors from a failed cluster. Our approach avoids a full-scale re-clustering and does not require deployment of redundant gateways.
Reversible and blind database watermarking using difference expansion
School of Electrical Engineering Computer Science Science Engineering Faculty, Apr 1, 2011
ABSTRACT Database watermarking has received significant research attention in the current decade.... more ABSTRACT Database watermarking has received significant research attention in the current decade. Although, almost all watermarking models have been either irreversible (the original relation cannot be restored from the watermarked relation) and/or non-blind (requiring original relation to detect the watermark in watermarked relation). This model has several disadvantages over reversible and blind watermarking (requiring only watermarked relation and secret key from which the watermark is detected and original relation is restored) including inability to identify rightful owner in case of successful secondary watermarking, inability to revert the relation to original data set (required in high precision industries) and requirement to store unmarked relation at a secure secondary storage. To overcome these problems, we propose a watermarking scheme that is reversible as well as blind. We utilize difference expansion on integers to achieve reversibility. The major advantages provided by our scheme are reversibility to high quality original data set, rightful owner identification, resistance against secondary watermarking attacks, and no need to store original database at a secure secondary storage.
Source Code Watermarking Based on Function Dependency Oriented Sequencing
Proceedings of the 2008 International Conference on Intelligent Information Hiding and Multimedia Signal Processing, 2008
In the current market, extensive software development is taking place and the software industry i... more In the current market, extensive software development is taking place and the software industry is thriving. Major software giants have stated source code theft as a major threat to revenues. By inserting an identity-establishing wa-termark in the source code, a company can ...
Role of a thermo-mechanical treatment on the subgrain boundary density and on creep behavior of ferritic-martensitic alloy T91
The objective of this thesis is twofold; to determine a thermo-mechanical treatment to enhance th... more The objective of this thesis is twofold; to determine a thermo-mechanical treatment to enhance the subgrain boundary density in ferritic-martensitic (F-M) alloy T91, and to quantify the increased creep strength due to the higher subgrain boundary density. It was observed that a thermo-mechanical treatment involving 5% compression treatment, followed by an annealing treatment at 1050°C for one h: air cool and a tempering treatment at 800°C for 40 min: air cool, resulted in an increase in the subgrain boundary density by ˜39% without changing any of the other microstructural features. Creep tests were conducted on both the as-received (AR) and subgrain boundary enhanced (SGBE) conditions of F-M alloy T91 in a stress range of 150-255MPa and over a temperature range of 500-600°C in argon. Creep behavior was analyzed on the basis of the Orowan equation, according to which creep rate is controlled by dislocation velocity and mobile dislocation density. Under all test conditions T91-SGBE exhibited a lower minimum creep rate by a factor of ˜2-3.5 and a longer time to rupture as compared to T91-AR by a factor of ˜1.03-5. Dislocation density evolution was studied after a short-term creep test conducted at 600°C: 155MPa to a strain of 0.017. Dislocation density decreased during creep by ˜20% for both conditions, though the T91-AR took 7 h to reach that strain, while T91-SGBE required 21 h, indicating a higher rate of dislocation annihilation in T91-AR as compared to T91-SGBE. Internal stress calculations performed on both conditions revealed a higher internal stress in the SGBE condition as compared to the AR condition; by ˜10MPa. A higher internal stress in the SGBE condition reduced the effective stress and increased the creep strength. The additional internal stress in the SGBE condition is likely due to the enhanced subgrain boundary density. The temperature increment benefit due to subgrain boundary density enhancement increases exponentially with applied stress and the increase is slightly higher at 600°C as compared to 550°C, which is again slightly higher as compared to 500°C. The activation energy was similar for the two conditions, confirming that the operating creep mechanism was similar for both conditions.
Generation of Microwave Second Harmonic and Sum and Difference Frequency in Semiconductors at Low Temperatures
Journal of the Physical Society of Japan, Sep 15, 1968
The generation of microwave second harmonic and sum and difference frequency has been investigate... more The generation of microwave second harmonic and sum and difference frequency has been investigated analytically when two microwaves of frequencies omega1 and omega2 are incident normally on a semiconducting slab in the presence of a d.c. field. The analysis takes into account acoustic phonon scattering as well as ionized impurity scattering of electrons. For a typical case of germanium slab the amplitudes of reflected and transmitted components of second harmonic waves are 8.8% and 5.4% respectively of that of the fundamental wave.
E-mail has revolutionized business, academic, and personal communication The advantages of e-mail... more E-mail has revolutionized business, academic, and personal communication The advantages of e-mail include speedy delivery, ease of communication, cost effectiveness, geographical independence, and the portability of mailboxes. The last two are the biggest advantages over snail mail. However, with e-mail comes the threat of a genuine user being compromised through key loggers, social engineering, shoulder surfing, password guessing and other similar, though less technical, methods. This passive espionage can have a direct impact on the genuine user in terms of denial of information, loss of money, loss of time, mental harassment and an attack of personal privacy. To enable digital forensic analysis of e-mails, we propose behavioral biometric based authentication, which is analogous to a signature in paper documents. In the proposed system, if someone other than a genuine user tries to authenticate himself, then detection and fixing is possible.
Robust Modelling and Tracking of NonRigid Objects Using Active-GNG
Proceedings Ieee International Conference on Computer Vision Ieee International Conference on Computer Vision, 2007
Abstract This paper presents a robust approach to nonrigid modelling and tracking. The contour of... more Abstract This paper presents a robust approach to nonrigid modelling and tracking. The contour of the object is described by an active growing neural gas (A-GNG) network which allows the model to re-deform locally. The approach is novel in that the nodes of the ...
The Journals of Gerontology Series a Biological Sciences and Medical Sciences, Mar 1, 1999
Departmentof Medicine, Divisions of 'Geriatrics, 2Endocrinology, and the 3Diabetes ResearchandTra... more Departmentof Medicine, Divisions of 'Geriatrics, 2Endocrinology, and the 3Diabetes ResearchandTrainingCenter, AlbertEinstein Collegeof Medicine, Montefiore MedicalCenter,Bronx,NewYork. One ofthe most robustobservations in the biologyofaging is that caloric restriction (CR) extendsUfe in a variety ofspecies. A1Jhough CR resultsin a severalfold decrease infat mass (FM), the roleoffat on Ufe extensionwasconsideredto be minimal; Twomain reasonsaccountedfor this belief,First, aIthoughincreasedFM is associated withchangesin substrate oxidation and in glucose homeostasis, in palt through the effectsoffree fatty acids (FFA) and glycero4 severalstudieshave suggestedthat longevity is determined independentofFM. Second, CR has systemk effects on a range of functions including neurological; endocrine, reproductive, immunologicaland anuneoplastic, none of which havebeen historically linked tofat. In the last few years,an explosion ofevidence has demonstrated thatfat tissueis a veryactiveendocrine gland which. secretes a variety ofpeptides(such as leptinand plasminogenactivating inhibitor-I), cytokines(such as tumor necrosisfactor), and complementfactors(suchas D, C3,and B). This is in addition to thepresenceofsubstrates, such as glyceroland FFA, whicn are storedand releasedbyfat cellsand are known to havea majorrolein hepaticandperipheral glucosemetabolism. Wepropose that many ofthe systemU: effectsofCR can now be explainedby the chronic effectsrelatedto decreased plasma levels of peptides, cytokines, complementfactors, and substrates. In fact, all ofthe benefitsof CR on the neuroendocrine systemand those relatedto the improvement in glucose homeostasis can be attributed to decrease in adipose cellsand their products. Other evidencefrom epidemiological data in human obesity supports the role offat mass and its bodydistribution as a risk factorfor morbidity and morlillity in humans due to impairedglucosemetabolism (simi1ar to rodents), for cancer (simi1ar to rodents), andfor the development ofatherosclerotic vascular disease (in humans). Ifall or most ofthe Ufe-extending benefus of CR can be attributed to decreased fat stores, the expression of specijic candidate proteinsmay be exploredand manipulatedin the searchfor the mostpoweljul adipose-dependent signalsthat modulateUfe expectancy.
Cross-sectional Transmission Electron Microscopy and Optical Characterization of Gold Nanoislands
Japanese Journal of Applied Physics, Aug 1, 2009
In this paper, we present the cross-sectional transmission electron microscope images of gold nan... more In this paper, we present the cross-sectional transmission electron microscope images of gold nanoislands formed by annealing ultrathin gold films to correctly determine the nanoisland three-dimensional shapes. The samples studied were 5 and 7 nm gold films deposited on quartz and annealed at 500 and 900 °C. The cross-sectional view of the gold nanoislands confirmed that they appear to be like truncated spheres and not like the usually assumed spheroids. The shape of the nanoislands varied from spherical to hemispherical under different sample fabrication conditions. These shapes are consistent with the results predicted by polarized absorption spectroscopy.
On the degrees of freedom in linear array systems with tri-polarized antennas
Ieee Transactions on Wireless Communications, 2008
AbstractIn this paper, we provide a theoretical, simulation and experimental characterization of... more AbstractIn this paper, we provide a theoretical, simulation and experimental characterization of the performance of linear arrays of tri-polarized dipole antennas in Multiple Input Mul-tiple Output (MIMO) systems in terms of degrees of freedom and channel capacity. Specifically, ...
Role of open nephron sparing surgery in the era of minimal invasive surgery
Indian Journal of Urology, 2009
Objective : The study aims to review the current status of nephron sparing surgery - open partial... more Objective : The study aims to review the current status of nephron sparing surgery - open partial nephrectomy (OPN) for renal cell carcinoma in the minimal invasive era. The literature search was done using National Library of Medicine database (PubMed). Results : Early experience with laparoscopic partial nephrectomy is promising. It has an inherent advantage of less operative time, decreased operative blood loss and a shorter hospital stay at the expense of prolonged ischemia and operative time. Complex scenarios for partial nephrectomy such as centrally located tumor, tumor in a solitary kidney, predominantly cystic tumor, and multifocal disease probably are managed best with an open technique. All these challenging situations have been addressed successfully by experienced laparoscopic surgeons, therefore these conditions are best considered relative rather than absolute contraindications for laparoscopic partial nephrectomy. Conclusions : Laparoscopic partial nephrectomy faces the problem of technical complexity and availability of expertise. Open partial nephrectomy continues to be the gold standard for nephron sparing surgery.
2003 IEEE Wireless Communications and Networking, 2003. WCNC 2003., 2000
During the past few years, distributed wireless sensor networks have been the focus of considerab... more During the past few years, distributed wireless sensor networks have been the focus of considerable research for both military and civil applications. Sensors are generally constrained in on-board energy supply therefore efficient management of the network is crucial to extend the life of the system. Sensors' energy cannot support long haul communication to reach a remote command site, thus they require multi-tier architecture to forward data. An efficient way to enhance the lifetime of the system is to partition the network into distinct clusters with a high-energy node called gateway as cluster-head. Failures are inevitable in sensor networks due to the inhospitable environment and unattended deployment. However, failures in higher level of hierarchy e.g. cluster-head cause more damage to the system because they also limit accessibility to the nodes that are under their supervision. In this paper we propose an efficient mechanism to recover sensors from a failed cluster. Our approach avoids a full-scale re-clustering and does not require deployment of redundant gateways.
Reversible and blind database watermarking using difference expansion
School of Electrical Engineering Computer Science Science Engineering Faculty, Apr 1, 2011
ABSTRACT Database watermarking has received significant research attention in the current decade.... more ABSTRACT Database watermarking has received significant research attention in the current decade. Although, almost all watermarking models have been either irreversible (the original relation cannot be restored from the watermarked relation) and/or non-blind (requiring original relation to detect the watermark in watermarked relation). This model has several disadvantages over reversible and blind watermarking (requiring only watermarked relation and secret key from which the watermark is detected and original relation is restored) including inability to identify rightful owner in case of successful secondary watermarking, inability to revert the relation to original data set (required in high precision industries) and requirement to store unmarked relation at a secure secondary storage. To overcome these problems, we propose a watermarking scheme that is reversible as well as blind. We utilize difference expansion on integers to achieve reversibility. The major advantages provided by our scheme are reversibility to high quality original data set, rightful owner identification, resistance against secondary watermarking attacks, and no need to store original database at a secure secondary storage.
Source Code Watermarking Based on Function Dependency Oriented Sequencing
Proceedings of the 2008 International Conference on Intelligent Information Hiding and Multimedia Signal Processing, 2008
In the current market, extensive software development is taking place and the software industry i... more In the current market, extensive software development is taking place and the software industry is thriving. Major software giants have stated source code theft as a major threat to revenues. By inserting an identity-establishing wa-termark in the source code, a company can ...
Role of a thermo-mechanical treatment on the subgrain boundary density and on creep behavior of ferritic-martensitic alloy T91
The objective of this thesis is twofold; to determine a thermo-mechanical treatment to enhance th... more The objective of this thesis is twofold; to determine a thermo-mechanical treatment to enhance the subgrain boundary density in ferritic-martensitic (F-M) alloy T91, and to quantify the increased creep strength due to the higher subgrain boundary density. It was observed that a thermo-mechanical treatment involving 5% compression treatment, followed by an annealing treatment at 1050°C for one h: air cool and a tempering treatment at 800°C for 40 min: air cool, resulted in an increase in the subgrain boundary density by ˜39% without changing any of the other microstructural features. Creep tests were conducted on both the as-received (AR) and subgrain boundary enhanced (SGBE) conditions of F-M alloy T91 in a stress range of 150-255MPa and over a temperature range of 500-600°C in argon. Creep behavior was analyzed on the basis of the Orowan equation, according to which creep rate is controlled by dislocation velocity and mobile dislocation density. Under all test conditions T91-SGBE exhibited a lower minimum creep rate by a factor of ˜2-3.5 and a longer time to rupture as compared to T91-AR by a factor of ˜1.03-5. Dislocation density evolution was studied after a short-term creep test conducted at 600°C: 155MPa to a strain of 0.017. Dislocation density decreased during creep by ˜20% for both conditions, though the T91-AR took 7 h to reach that strain, while T91-SGBE required 21 h, indicating a higher rate of dislocation annihilation in T91-AR as compared to T91-SGBE. Internal stress calculations performed on both conditions revealed a higher internal stress in the SGBE condition as compared to the AR condition; by ˜10MPa. A higher internal stress in the SGBE condition reduced the effective stress and increased the creep strength. The additional internal stress in the SGBE condition is likely due to the enhanced subgrain boundary density. The temperature increment benefit due to subgrain boundary density enhancement increases exponentially with applied stress and the increase is slightly higher at 600°C as compared to 550°C, which is again slightly higher as compared to 500°C. The activation energy was similar for the two conditions, confirming that the operating creep mechanism was similar for both conditions.
Generation of Microwave Second Harmonic and Sum and Difference Frequency in Semiconductors at Low Temperatures
Journal of the Physical Society of Japan, Sep 15, 1968
The generation of microwave second harmonic and sum and difference frequency has been investigate... more The generation of microwave second harmonic and sum and difference frequency has been investigated analytically when two microwaves of frequencies omega1 and omega2 are incident normally on a semiconducting slab in the presence of a d.c. field. The analysis takes into account acoustic phonon scattering as well as ionized impurity scattering of electrons. For a typical case of germanium slab the amplitudes of reflected and transmitted components of second harmonic waves are 8.8% and 5.4% respectively of that of the fundamental wave.
E-mail has revolutionized business, academic, and personal communication The advantages of e-mail... more E-mail has revolutionized business, academic, and personal communication The advantages of e-mail include speedy delivery, ease of communication, cost effectiveness, geographical independence, and the portability of mailboxes. The last two are the biggest advantages over snail mail. However, with e-mail comes the threat of a genuine user being compromised through key loggers, social engineering, shoulder surfing, password guessing and other similar, though less technical, methods. This passive espionage can have a direct impact on the genuine user in terms of denial of information, loss of money, loss of time, mental harassment and an attack of personal privacy. To enable digital forensic analysis of e-mails, we propose behavioral biometric based authentication, which is analogous to a signature in paper documents. In the proposed system, if someone other than a genuine user tries to authenticate himself, then detection and fixing is possible.
Robust Modelling and Tracking of NonRigid Objects Using Active-GNG
Proceedings Ieee International Conference on Computer Vision Ieee International Conference on Computer Vision, 2007
Abstract This paper presents a robust approach to nonrigid modelling and tracking. The contour of... more Abstract This paper presents a robust approach to nonrigid modelling and tracking. The contour of the object is described by an active growing neural gas (A-GNG) network which allows the model to re-deform locally. The approach is novel in that the nodes of the ...
The Journals of Gerontology Series a Biological Sciences and Medical Sciences, Mar 1, 1999
Departmentof Medicine, Divisions of 'Geriatrics, 2Endocrinology, and the 3Diabetes ResearchandTra... more Departmentof Medicine, Divisions of 'Geriatrics, 2Endocrinology, and the 3Diabetes ResearchandTrainingCenter, AlbertEinstein Collegeof Medicine, Montefiore MedicalCenter,Bronx,NewYork. One ofthe most robustobservations in the biologyofaging is that caloric restriction (CR) extendsUfe in a variety ofspecies. A1Jhough CR resultsin a severalfold decrease infat mass (FM), the roleoffat on Ufe extensionwasconsideredto be minimal; Twomain reasonsaccountedfor this belief,First, aIthoughincreasedFM is associated withchangesin substrate oxidation and in glucose homeostasis, in palt through the effectsoffree fatty acids (FFA) and glycero4 severalstudieshave suggestedthat longevity is determined independentofFM. Second, CR has systemk effects on a range of functions including neurological; endocrine, reproductive, immunologicaland anuneoplastic, none of which havebeen historically linked tofat. In the last few years,an explosion ofevidence has demonstrated thatfat tissueis a veryactiveendocrine gland which. secretes a variety ofpeptides(such as leptinand plasminogenactivating inhibitor-I), cytokines(such as tumor necrosisfactor), and complementfactors(suchas D, C3,and B). This is in addition to thepresenceofsubstrates, such as glyceroland FFA, whicn are storedand releasedbyfat cellsand are known to havea majorrolein hepaticandperipheral glucosemetabolism. Wepropose that many ofthe systemU: effectsofCR can now be explainedby the chronic effectsrelatedto decreased plasma levels of peptides, cytokines, complementfactors, and substrates. In fact, all ofthe benefitsof CR on the neuroendocrine systemand those relatedto the improvement in glucose homeostasis can be attributed to decrease in adipose cellsand their products. Other evidencefrom epidemiological data in human obesity supports the role offat mass and its bodydistribution as a risk factorfor morbidity and morlillity in humans due to impairedglucosemetabolism (simi1ar to rodents), for cancer (simi1ar to rodents), andfor the development ofatherosclerotic vascular disease (in humans). Ifall or most ofthe Ufe-extending benefus of CR can be attributed to decreased fat stores, the expression of specijic candidate proteinsmay be exploredand manipulatedin the searchfor the mostpoweljul adipose-dependent signalsthat modulateUfe expectancy.
Cross-sectional Transmission Electron Microscopy and Optical Characterization of Gold Nanoislands
Japanese Journal of Applied Physics, Aug 1, 2009
In this paper, we present the cross-sectional transmission electron microscope images of gold nan... more In this paper, we present the cross-sectional transmission electron microscope images of gold nanoislands formed by annealing ultrathin gold films to correctly determine the nanoisland three-dimensional shapes. The samples studied were 5 and 7 nm gold films deposited on quartz and annealed at 500 and 900 °C. The cross-sectional view of the gold nanoislands confirmed that they appear to be like truncated spheres and not like the usually assumed spheroids. The shape of the nanoislands varied from spherical to hemispherical under different sample fabrication conditions. These shapes are consistent with the results predicted by polarized absorption spectroscopy.
On the degrees of freedom in linear array systems with tri-polarized antennas
Ieee Transactions on Wireless Communications, 2008
AbstractIn this paper, we provide a theoretical, simulation and experimental characterization of... more AbstractIn this paper, we provide a theoretical, simulation and experimental characterization of the performance of linear arrays of tri-polarized dipole antennas in Multiple Input Mul-tiple Output (MIMO) systems in terms of degrees of freedom and channel capacity. Specifically, ...
Role of open nephron sparing surgery in the era of minimal invasive surgery
Indian Journal of Urology, 2009
Objective : The study aims to review the current status of nephron sparing surgery - open partial... more Objective : The study aims to review the current status of nephron sparing surgery - open partial nephrectomy (OPN) for renal cell carcinoma in the minimal invasive era. The literature search was done using National Library of Medicine database (PubMed). Results : Early experience with laparoscopic partial nephrectomy is promising. It has an inherent advantage of less operative time, decreased operative blood loss and a shorter hospital stay at the expense of prolonged ischemia and operative time. Complex scenarios for partial nephrectomy such as centrally located tumor, tumor in a solitary kidney, predominantly cystic tumor, and multifocal disease probably are managed best with an open technique. All these challenging situations have been addressed successfully by experienced laparoscopic surgeons, therefore these conditions are best considered relative rather than absolute contraindications for laparoscopic partial nephrectomy. Conclusions : Laparoscopic partial nephrectomy faces the problem of technical complexity and availability of expertise. Open partial nephrectomy continues to be the gold standard for nephron sparing surgery.
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Papers by GAURAV GUPTA