The Experts below are selected from a list of 125838 Experts worldwide ranked by ideXlab platform
Jian-kang Zhang - One of the best experts on this subject based on the ideXlab platform.
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Blind transmission and detection designs with Unique Identification and full diversity for noncoherent two-way relay networks
IEEE Transactions on Vehicular Technology, 2014Co-Authors: Yanwu Ding, Jian-kang ZhangAbstract:This paper considers blind detection for a two-way relay system in which two source nodes exchange information with each other via a relay node using an amplify-and-forward (AF) protocol. The channel coefficients are assumed to be nonreciprocal, i.e., the channel gain between two nodes is not identical to that in the reverse link between the same nodes. An effective signaling and transmitting scheme using four M-ary phase-shift keying (M-PSK) constellation sets is proposed to achieve a Unique Identification of the transmitted symbols and the channel coefficients in a noise-free transmission. Blind receivers with full diversity are derived for Rayleigh fading channels with Gaussian noise by the generalized likelihood ratio test (GLRT) and least squares error (LSE) criteria. Constellation selections are investigated for the source nodes to transmit at a uniform bit rate in each time slot. Power-allocation schemes are discussed to improve further the average error probability of the source nodes in the blind detection. Simulation results are provided to validate the proposed designs.
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Full Diversity Blind Signal Designs for Unique Identification of Frequency Selective Channels
IEEE Transactions on Vehicular Technology, 2012Co-Authors: Jian-kang Zhang, Chau Yuen, Fei HuangAbstract:In this paper, we develop two kinds of closed-form decompositions on phase-shift-keying (PSK) constellations by exploiting linear congruence equation theory: the one for factorizing a pq-PSK constellation into a product of p- and q-PSK constellations and the other for decomposing a specific complex number into a difference of a point in p-PSK constellation and a point in q-PSK constellation. With this, we present a novel and simple signal design technique to blindly and Uniquely identify frequency selective channels with zero-padded block transmission by only processing the first two block received signals. In a noise-free case, a closed-form solution to determine the transmitted signals and the channel coefficients is obtained. In a Gaussian noise and Rayleigh fading environment, we prove that our scheme enables full diversity for the generalized likelihood ratio test (GLRT) receiver. When only finite received data are given, the linearity of our signal design allows us to use iterative sphere decoders to approximate GLRT detection so that the joint estimation of the channel and symbols can be efficiently implemented.
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Blind Detection with Unique Identification in Two-Way Relay Channel
IEEE Transactions on Wireless Communications, 2012Co-Authors: Yanwu Ding, Jian-kang Zhang, Rui ZhangAbstract:This paper considers the blind detection for a two-way relay system in which two source nodes exchange information via a relay node by amplify-and-forward relaying. An efficient transmission scheme is first proposed to achieve Unique Identifications of both the transmitted symbols and channel coefficients at a noise-free receiver using the M-ary phase shift keying modulation. Blind receivers based on the generalized likelihood ratio test are then derived for both the reciprocal and nonreciprocal channels with additive Gaussian noise. The least square error-based receiver is also studied for the case without prior knowledge of the noise power for detection. Moreover, constellation selection algorithms are proposed to achieve a uniform transmission bit rate for the ease of implementation. Finally, numerical results are provided to validate the proposed schemes.
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Blind Unique Identification of MIMO Channels Using Signal Designs and High-Order Moments
IEEE Signal Processing Letters, 2010Co-Authors: Jian-kang Zhang, Fei HuangAbstract:In this letter, a necessary and sufficient condition is developed to check whether a set of polynomial equations is solvable. Furthermore, under the sufficient condition, a closed-form solution is attained using linear Diophantine equation theory. With this, a novel signal design and a row-circular transmission scheme of phase shift keying (PSK) constellations for MIMO flat fading channels are proposed so that the channel coefficients can be Uniquely identified. When certain high-order moments of the received signals are available, a closed-form solution to Uniquely determine the channel coefficients is given. When only finite received data are available, a numerical algorithm is provided to efficiently and effectively estimate the channel.
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Full Diversity Blind Alamouti Space–Time Block Codes for Unique Identification of Flat-Fading Channels
IEEE Transactions on Signal Processing, 2009Co-Authors: Jian-kang ZhangAbstract:In this paper, we consider a systematic design of a full diversity blind Alamouti space-time block code for a wireless communication system having two transmitter antennas and a single receiver antenna, in which the channel is completely unknown at both the transmitter and the receiver. The key idea is to alternatively transmit Alamouti codes with different phase shift keying (PSK) constellations, say, with p -PSK and q -PSK. To provide the theoretical analysis of its Unique Identification and full diversity conditions, we first establish a general theorem for factorizing a pq-PSK constellation into a product of a p -PSK constellation and a q -PSK constellation. Then, we prove that a necessary and sufficient condition for both the factorization and a set of solutions of the resulting Alamouti Diophantine equation from our code design to be Unique is that p and q are coprime. The same condition assures that the channel and the transmitted signal can be blindly and Uniquely identified. Furthermore, a closed-form solution to determine the channel coefficients and the transmitted symbols are obtained. Also, we prove that our code enables full diversity for the generalized-likelihood ratio test (GLRT) receiver if p and q are coprime. When finite length of the received data is available, the unitarity and linearity of our code design allow us to utilize the semi-definite relaxation (SDR) decoder or the sphere decoder so that the joint estimation of the channel and symbols can be efficiently implemented.
Stephen J. Eichhorn - One of the best experts on this subject based on the ideXlab platform.
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Unique Identification of Single-Walled Carbon Nanotubes in Electrospun Fibers
The Journal of Physical Chemistry C, 2014Co-Authors: Libo Deng, Robert J. Young, Rong Sun, Guoping Zhang, Stephen J. EichhornAbstract:Single-walled carbon nanotubes (SWNTs) have been exfoliated in a poly(vinyl alcohol) (PVA) matrix using electrospinning. Raman features of SWNTs with single chirality were studied systematically in terms of the band frequency, intensity, and full width at half-maximum (fwhm). Polarized Raman spectroscopy was used to investigate the orientation of SWNTs, and it was found they were highly aligned along the fiber axis. The response of the nanotube G′-band to external strain for SWNT has been found to be dependent on the nanotube chirality, which suggests nonuniform efficiency of mechanical reinforcement for different nanotube species. The preparation and characterization methods demonstrated in this study have led to a better understanding of the effects of aggregation state, chirality, and external strain on the properties of nanotubes that are incorporated in a polymer matrix.
Robert J. Young - One of the best experts on this subject based on the ideXlab platform.
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Foreword to "Using Imperfect Semiconductor Systems for Unique Identification"
2017Co-Authors: Robert J. YoungAbstract:This thesis describes novel devices for the secure Identification of objects or electronic systems. The Identification relies on the the atomic-scale Uniqueness of semiconductor devices by measuring a macroscopic quantum property of the system in question. Traditionally, objects and electronic systems have been securely identified by measuring specific characteristics: common examples include passwords, fingerprints used to identify a person or an electronic device, and holograms that can tag a given object to prove its authenticity. Unfortunately, modern technologies also make it possible to circumvent these everyday techniques. Variations in quantum properties are amplified by the existence of atomic-scale imperfections. As such, these devices are the hardest possible systems to clone. They also use the least resources and provide robust security. Hence they have tremendous potential significance as a means of reliably telling the good guys from the bad.
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Using quantum effects in nanomaterials for Unique Identification
2016Co-Authors: Robert J. Young, Jonathan Roberts, Phillip SpeedAbstract:Authentication and Identification are critical to information security systems. Traditionally, these processes are achieved with the use of secret keys that are stored in electronic memories, or with difficult-to-clone systems (e.g., fingerprints or holograms). The persistent development of technology, however, means that the barrier to cloning such systems is becoming lower. Moreover, counterfeiting, device spoofing, and identity fraud are formidable problems in all markets. The ideal solution, therefore, would be to produce a nano-fingerprint from the atomic arrangement of a structure embedded within a device. By shrinking down to the atomic scale, the challenge of cloning the system becomes as difficult as possible, i.e., the density of secure information is maximized and the number of resources required to read the fingerprint is minimized.
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Unique Identification of Single-Walled Carbon Nanotubes in Electrospun Fibers
The Journal of Physical Chemistry C, 2014Co-Authors: Libo Deng, Robert J. Young, Rong Sun, Guoping Zhang, Stephen J. EichhornAbstract:Single-walled carbon nanotubes (SWNTs) have been exfoliated in a poly(vinyl alcohol) (PVA) matrix using electrospinning. Raman features of SWNTs with single chirality were studied systematically in terms of the band frequency, intensity, and full width at half-maximum (fwhm). Polarized Raman spectroscopy was used to investigate the orientation of SWNTs, and it was found they were highly aligned along the fiber axis. The response of the nanotube G′-band to external strain for SWNT has been found to be dependent on the nanotube chirality, which suggests nonuniform efficiency of mechanical reinforcement for different nanotube species. The preparation and characterization methods demonstrated in this study have led to a better understanding of the effects of aggregation state, chirality, and external strain on the properties of nanotubes that are incorporated in a polymer matrix.
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Unique Identification of single-walled carbon nanotubes in composites
Composites Science and Technology, 2007Co-Authors: Marcel Lucas, Robert J. YoungAbstract:Abstract The physical properties of single-walled carbon nanotubes (SWNTs) depend strongly upon their structure and so a reliable method to determine this structure is essential to their future applications. Resonant Raman spectroscopy has proven to be a powerful tool to characterize SWNTs, and also to monitor their deformation. The radial breathing modes (RBMs) are commonly used to identify SWNTs, since their position is inversely proportional to the nanotube diameter. In this present study, the RBM intensity variations in epoxy- and poly(vinyl alcohol) (PVA)-SWNTs composites were measured under uniaxial strain using lasers of three wavelengths 632, 785 and 830 nm. These structure-dependent intensity variations are attributed to the effect of strain upon the energy of the SWNT electronic transitions, moving SWNTs closer to or further away from the resonance conditions that enhance the Raman signal. Combining the RBM position, resonance theory and this additional information about the behaviour under strain, a Unique nanotube structure can be assigned to each RBM observed in the composites.
Thomas G. Rizzo - One of the best experts on this subject based on the ideXlab platform.
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Unique Identification of Lee-Wick Gauge Bosons at Linear Colliders ∗†
Journal of High Energy Physics, 2008Co-Authors: Thomas G. RizzoAbstract:Grinstein, O'Connell and Wise have recently presented an extension of the Standard Model (SM), based on the ideas of Lee and Wick (LW), which demonstrates an interesting way to remove the quadratically divergent contributions to the Higgs mass induced by radiative corrections. This model predicts the existence of negative-norm copies of the usual SM fields at the TeV scale with ghost-like propagators and negative decay widths, but with otherwise SM-like couplings. In earlier work, it was demonstrated that the LW states in the gauge boson sector of these models, though easy to observe, cannot be Uniquely identified as such at the LHC. In this paper, we address the issue of whether or not this problem can be resolved at an e{sup +}e{sup -} collider with a suitable center of mass energy range. We find that measurements of the cross section and the left-right polarization asymmetry associated with Bhabha scattering can lead to a Unique Identification of the neutral electroweak gauge bosons of the Lee-Wick type.
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Unique Identification of lee wick gauge bosons at linear colliders
arXiv: High Energy Physics - Phenomenology, 2007Co-Authors: Thomas G. RizzoAbstract:Grinstein, O'Connell and Wise have recently presented an extension of the Standard Model (SM), based on the ideas of Lee and Wick (LW), which demonstrates an interesting way to remove the quadratically divergent contributions to the Higgs mass induced by radiative corrections. This model predicts the existence of negative-norm copies of the usual SM fields at the TeV scale with ghost-like propagators and negative decay widths, but with otherwise SM-like couplings. In earlier work, it was demonstrated that the LW states in the gauge boson sector of these models, though easy to observe, cannot be Uniquely identified as such at the LHC. In this paper, we address the issue of whether or not this problem can be resolved at an $e^+e^-$ collider with a suitable center of mass energy range. We find that measurements of the cross section and the left-right polarization asymmetry associated with Bhabha scattering can lead to a Unique Identification of the neutral electroweak gauge bosons of the Lee-Wick type.
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Unique Identification of Graviton Exchange Effects in e+e- Collisions
Journal of High Energy Physics, 2002Co-Authors: Thomas G. RizzoAbstract:Many types of new physics can lead to contact interaction-like modifications in e{sup +}e{sup -} processes below direct production threshold. We examine the possibility of Uniquely identifying the effects of graviton exchange, which are anticipated in many extra dimensional theories, from amongst this large set of models by using the moments of the angular distribution of the final state particles. In the case of the e{sup +}e{sup -} {yields} f{bar f} process we demonstrate that this technique allows for the Unique Identification of the graviton exchange signature at the 5{sigma} level for mass scales as high as 6{radical}s. The extension of this method to the e{sup +}e{sup -} {yields} W{sup +}W{sup -} process is also discussed.
Libo Deng - One of the best experts on this subject based on the ideXlab platform.
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Unique Identification of Single-Walled Carbon Nanotubes in Electrospun Fibers
The Journal of Physical Chemistry C, 2014Co-Authors: Libo Deng, Robert J. Young, Rong Sun, Guoping Zhang, Stephen J. EichhornAbstract:Single-walled carbon nanotubes (SWNTs) have been exfoliated in a poly(vinyl alcohol) (PVA) matrix using electrospinning. Raman features of SWNTs with single chirality were studied systematically in terms of the band frequency, intensity, and full width at half-maximum (fwhm). Polarized Raman spectroscopy was used to investigate the orientation of SWNTs, and it was found they were highly aligned along the fiber axis. The response of the nanotube G′-band to external strain for SWNT has been found to be dependent on the nanotube chirality, which suggests nonuniform efficiency of mechanical reinforcement for different nanotube species. The preparation and characterization methods demonstrated in this study have led to a better understanding of the effects of aggregation state, chirality, and external strain on the properties of nanotubes that are incorporated in a polymer matrix.
