The Experts below are selected from a list of 18273 Experts worldwide ranked by ideXlab platform
Sandeep S Pradhan - One of the best experts on this subject based on the ideXlab platform.
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computing sum of sources over an arbitrary multiple access channel
International Symposium on Information Theory, 2013Co-Authors: Arun Padakandla, Sandeep S PradhanAbstract:The problem of computing sum of sources over a multiple access channel (MAC) is considered. Building on the technique of linear computation coding (LCC) proposed by Nazer and Gastpar [1], we employ the ensemble of nested Coset codes to derive a new set of sufficient conditions for computing sum of sources over an arbitrary MAC. The optimality of nested Coset codes [2] enables this technique outperform LCC even for linear MAC with a structural match. Examples of non-additive MAC for which the technique proposed herein outperforms separation and systematic based computation are also presented. Finally, this technique is enhanced by incorporating separation based strategy, leading to a new set of sufficient conditions for computing sum over a MAC.
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achievable rate region based on Coset codes for multiple access channel with states
International Symposium on Information Theory, 2013Co-Authors: Arun Padakandla, Sandeep S PradhanAbstract:We derive a new achievable rate region for the problem of communicating over a multiple access channel with states. Our coding technique is based on the ensemble of nested Coset codes and the technique of typicality decoding. Exploiting structure in this ensemble, we analyze a more efficient decoding strategy to improve upon the rate region achievable using unstructured codes. We identify examples for which the achievable rate region based on nested Coset codes is strictly larger than the ones achievable using random unstructured codes.
Arun Padakandla - One of the best experts on this subject based on the ideXlab platform.
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computing sum of sources over an arbitrary multiple access channel
International Symposium on Information Theory, 2013Co-Authors: Arun Padakandla, Sandeep S PradhanAbstract:The problem of computing sum of sources over a multiple access channel (MAC) is considered. Building on the technique of linear computation coding (LCC) proposed by Nazer and Gastpar [1], we employ the ensemble of nested Coset codes to derive a new set of sufficient conditions for computing sum of sources over an arbitrary MAC. The optimality of nested Coset codes [2] enables this technique outperform LCC even for linear MAC with a structural match. Examples of non-additive MAC for which the technique proposed herein outperforms separation and systematic based computation are also presented. Finally, this technique is enhanced by incorporating separation based strategy, leading to a new set of sufficient conditions for computing sum over a MAC.
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achievable rate region based on Coset codes for multiple access channel with states
International Symposium on Information Theory, 2013Co-Authors: Arun Padakandla, Sandeep S PradhanAbstract:We derive a new achievable rate region for the problem of communicating over a multiple access channel with states. Our coding technique is based on the ensemble of nested Coset codes and the technique of typicality decoding. Exploiting structure in this ensemble, we analyze a more efficient decoding strategy to improve upon the rate region achievable using unstructured codes. We identify examples for which the achievable rate region based on nested Coset codes is strictly larger than the ones achievable using random unstructured codes.
Changhyun Ahn - One of the best experts on this subject based on the ideXlab platform.
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the Coset spin 4 casimir operator and its three point functions with scalars
arXiv: High Energy Physics - Theory, 2011Co-Authors: Changhyun AhnAbstract:We find the GKO Coset construction of the dimension 4 Casimir operator that contains the quartic WZW currents contracted with completely symmetric SU(N) invariant tensors of ranks 4, 3, and 2. The requirements, that the operator product expansion with the diagonal current is regular and it should be primary under the Coset Virasoro generator of dimension 2, fix all the coefficients in spin-4 current, up to two unknown coefficients. The operator product expansion of Coset primary spin-3 field with itself fixes them completely. We compute the three-point functions with scalars for all values of the 't Hooft coupling in the large N limit. At fixed 't Hooft coupling, these three-point functions are dual to that found by Chang and Yin recently in the undeformed AdS_3 bulk theory (higher spin gravity with matter).
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explicit construction of the spin 4 casimir operator in the Coset model so 5 1 so 5 m so 5 1 m
Journal of Physics A, 1994Co-Authors: Changhyun AhnAbstract:We generalize the Coset constructions to the dimension-5/2 operator for so(5) and compute the fourth-order Casimir invariant in the Coset model SO(5)1*SO(5)m/SO(5)1+m with the generic unitary minimal c<5/2 series that can be viewed as perturbations of the m to infinity limit, which has previously been investigated in the c=5/2 realization of the free fermion model.
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explicit construction of spin 4 casimir operator in the Coset model hat so 5 _ 1 times hat so 5 _ m hat so 5 _ 1 m
arXiv: High Energy Physics - Theory, 1992Co-Authors: Changhyun AhnAbstract:We generalize the Goddard-Kent-Olive (GKO) Coset construction to the dimension 5/2 operator for $ \hat{so} (5) $ and compute the fourth order Casimir invariant in the Coset model $\hat{SO} (5)_{1} \times \hat{SO} (5)_{m} / \hat{SO} (5)_{1+m} $ with the generic unitary minimal $ c < 5/2 $ series that can be viewed as perturbations of the $ m \rightarrow \infty $ limit, which has been investigated previously in the realization of $ c= 5/2 $ free fermion model.
Tadashi Wadayama - One of the best experts on this subject based on the ideXlab platform.
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average Coset weight distributions of gallager s ldpc code ensemble
IEEE Transactions on Information Theory, 2005Co-Authors: Tadashi WadayamaAbstract:In this correspondence, the average Coset weight distributions of Gallager's low-density parity-check (LDPC) code ensemble are investigated. Gallager's LDPC code ensemble consists of regular mtimesn-LDPC matrices with column weight j and row weight k. The average Coset weight distribution can be derived by enumerating the number of parity-check matrices in the ensemble satisfying certain conditions. Based on combinatorial arguments, a formula for the average Coset weight distribution will be proved. From the formula, we can show some properties of the average Coset weight distributions such as equivalence classes of syndromes, symmetry of the distributions, and a lower bound on Coset weight
Yutsuki Toyama - One of the best experts on this subject based on the ideXlab platform.
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model building by Coset space dimensional reduction in eight dimensions
Physics Letters B, 2009Co-Authors: Toshifumi Jittoh, Masafumi Koike, Takaaki Nomura, Joe Sato, Yutsuki ToyamaAbstract:Abstract We investigate gauge-Higgs unification models in eight-dimensional spacetime where extra-dimensional space has the structure of a four-dimensional compact Coset space. The combinations of the Coset space and the gauge group in the eight-dimensional spacetime of such models are listed. After the dimensional reduction of the Coset space, we identified SO ( 10 ) , SO ( 10 ) × U ( 1 ) and SO ( 10 ) × U ( 1 ) × U ( 1 ) as the possible gauge groups in the four-dimensional theory that can accomodate the Standard Model and thus is phenomenologically promising. Representations for fermions and scalars for these gauge groups are tabulated.
