The Experts below are selected from a list of 13053 Experts worldwide ranked by ideXlab platform
Yury Polyanskiy - One of the best experts on this subject based on the ideXlab platform.
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Bounds on the Reliability Function of Typewriter Channels
IEEE Transactions on Information Theory, 2018Co-Authors: Marco Dalai, Yury PolyanskiyAbstract:New lower and upper bounds on the reliability function of Typewriter channels are given. Our lower bounds improve upon the (multiletter) expurgated bound of Gallager, furnishing a new and simple counterexample to a conjecture made in 1967 by Shannon, Gallager and Berlekamp on its tightness. The only other known counter example is due to Katsman, Tsfasman and Vlăduţ who used algebraic-geometric codes on a $q$ -ary symmetric channels, $q\geq 49$ . Here we prove, by introducing dependence between codewords of a random ensemble, that the conjecture is false even for a Typewriter channel with $q=4$ inputs. In the process, we also demonstrate that Lovasz’s proof of the capacity of the pentagon was implicitly contained (but unnoticed!) in the works of Jelinek and Gallager on the expurgated bound done at least ten years before Lovasz. In the opposite direction, new upper bounds on the reliability function are derived for channels with an odd number of inputs by using an adaptation of Delsarte’s linear programming bound. First, we derive a bound based on the minimum distance, which combines Lovasz’s construction for bounding the graph capacity with the McEliece-Rodemich-Rumsey-Welch construction for bounding the minimum distance of codes in the Hamming space. Then, for the particular case of cross-over probability 1/2, we derive an improved bound by also using the method of Kalai and Linial to study the spectrum distribution of codes.
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bounds on the reliability of a Typewriter channel
International Symposium on Information Theory, 2016Co-Authors: Marco Dalai, Yury PolyanskiyAbstract:We give new bounds on the reliability function of a Typewriter channel with 5 inputs and crossover probability 1/2. The lower bound is more of theoretical than practical importance; it improves very marginally the expurgated bound, providing a counterexample to a conjecture on its tightness by Shannon, Gallager and Berlekamp which does not need the construction of algebraic-geometric codes previously used by Katsman, Tsfasman and Vladuţ. The upper bound is derived by using an adaptation of the linear programming bound and it is essentially useful as a low-rate anchor for the straight line bound.
Jae Jin Song - One of the best experts on this subject based on the ideXlab platform.
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Typewriter tinnitus revisited the typical symptoms and the initial response to carbamazepine are the most reliable diagnostic clues
Scientific Reports, 2017Co-Authors: Woongsang Sunwoo, Yun Jung Bae, Yung Jin Jeon, Ja Won Koo, Jeong Hun Jang, Jae Jin SongAbstract:Although neurovascular compression of the cochlear nerve (NVC-C) presenting as Typewriter tinnitus is a discrete disease category, verified diagnostic criteria are lacking. We sought to refine the diagnostic criteria for NVC-C by reference to a relatively large case series. The medical records of 22 NVC-C patients were retrospectively reviewed. Psychoacoustic characteristics, the results of diagnostic work-up (including audiovestibular neurophysiological tests and radiological evaluations), and the initial treatment response to carbamazepine were investigated. All subjects described their tinnitus as a typical “Typewriter” or “staccato” sound. Of the 22 subjects, 11 (50%) had histories of vertiginous spells, but none had ipsilesional hearing loss. Vestibular function tests in 11 subjects tested revealed only 2 (18.2%) isolated cervical vestibular evoked myogenic potential abnormalities. Radiological comparisons of the symptomatic and asymptomatic sides, regarding the type of the vascular loop and neurovascular contact, revealed no significant differences. However, all 22 subjects exhibited immediate and marked responses to short-term carbamazepine treatment. Meticulous history-taking in terms of the psychoacoustic characteristics and the response to initial carbamazepine, are more reliable diagnostic clues than are radiological or neurophysiological data in NVC-C subjects. Therefore, the typical psychoacoustic characteristics and the response to initial carbamazepine should be included in the diagnostic criteria.
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the role of mri in diagnosing neurovascular compression of the cochlear nerve resulting in Typewriter tinnitus
American Journal of Neuroradiology, 2017Co-Authors: Yun Jung Bae, Yung Jin Jeon, Byung Se Choi, Ja Won Koo, Jae Jin SongAbstract:BACKGROUND AND PURPOSE: Typewriter tinnitus, a symptom characterized by paroxysmal attacks of staccato sounds, has been thought to be caused by neurovascular compression of the cochlear nerve, but the correlation between radiologic evidence of neurovascular compression of the cochlear nerve and symptom presentation has not been thoroughly investigated. The purpose of this study was to examine whether radiologic evidence of neurovascular compression of the cochlear nerve is pathognomonic in Typewriter tinnitus. MATERIALS AND METHODS: Fifteen carbamazepine-responding patients with Typewriter tinnitus and 8 control subjects were evaluated with a 3D T2-weighted volume isotropic turbo spin-echo acquisition sequence. Groups 1 (16 symptomatic sides), 2 (14 asymptomatic sides), and 3 (16 control sides) were compared with regard to the anatomic relation between the vascular loop and the internal auditory canal and the presence of neurovascular compression of the cochlear nerve with/without angulation/indentation. RESULTS: The anatomic location of the vascular loop was not significantly different among the 3 groups (all, P > .05). Meanwhile, neurovascular compression of the cochlear nerve on MR imaging was significantly higher in group 1 than in group 3 (P = .032). However, considerable false-positive (no symptoms with neurovascular compression of the cochlear nerve on MR imaging) and false-negative (Typewriter tinnitus without demonstrable neurovascular compression of the cochlear nerve) findings were also observed. CONCLUSIONS: Neurovascular compression of the cochlear nerve was more frequently detected on the symptomatic side of patients with Typewriter tinnitus compared with the asymptomatic side of these patients or on both sides of control subjects on MR imaging. However, considering false-positive and false-negative findings, meticulous history-taking and the response to the initial carbamazepine trial should be regarded as more reliable diagnostic clues than radiologic evidence of neurovascular compression of the cochlear nerve.
Robert A. Levine - One of the best experts on this subject based on the ideXlab platform.
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Carbamazepine responsive Typewriter tinnitus from basilar invagination
Journal of neurology neurosurgery and psychiatry, 2010Co-Authors: Eui-cheol Nam, Ophir Handzel, Robert A. LevineAbstract:Basilar invagination due to a congenital skeletal disorder kinked the brainstem at the ponto-medullary junction causing both auditory nerves to make an acute turn at the porus acousticus. The associated bilateral asynchronous clicking tinnitus responded to carbamazepine.
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Typewriter tinnitus a carbamazepine responsive syndrome related to auditory nerve vascular compression
Operations Research Letters, 2006Co-Authors: Robert A. LevineAbstract:Six subjects with similar unilateral tinnitus that was fully suppressed by carbamazepine have been identified. Their ages at the time of the sudden onset of their tinnitus ranged from 39 to 87 years (
K Shikano - One of the best experts on this subject based on the ideXlab platform.
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phonetic Typewriter based on phoneme source modeling
International Conference on Acoustics Speech and Signal Processing, 1991Co-Authors: T Yamada, T Hanazawa, T Kawabata, S Matsunaga, K ShikanoAbstract:A phonetic Typewriter that utilizes the underlying statistical structure of phoneme/character sequences is described. The syllable/character trigram approach to language modeling is adopted to make language source models. These are obtained by calculating trigram probabilities, using a large text database. The phonetic Typewriter is tested using 279 phrases uttered by one male speaker, and the syllable source model achieves a 94.9% phoneme recognition rate with the test-set phoneme perplexity of 3.9. Without the syllable trigram, the phoneme recognition rate is only 73.2%. A trigram model based on characters is also evaluated. This model can reduce the phoneme perplexity significantly compared with that of the syllable trigram. >
Marco Dalai - One of the best experts on this subject based on the ideXlab platform.
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Bounds on the Reliability Function of Typewriter Channels
IEEE Transactions on Information Theory, 2018Co-Authors: Marco Dalai, Yury PolyanskiyAbstract:New lower and upper bounds on the reliability function of Typewriter channels are given. Our lower bounds improve upon the (multiletter) expurgated bound of Gallager, furnishing a new and simple counterexample to a conjecture made in 1967 by Shannon, Gallager and Berlekamp on its tightness. The only other known counter example is due to Katsman, Tsfasman and Vlăduţ who used algebraic-geometric codes on a $q$ -ary symmetric channels, $q\geq 49$ . Here we prove, by introducing dependence between codewords of a random ensemble, that the conjecture is false even for a Typewriter channel with $q=4$ inputs. In the process, we also demonstrate that Lovasz’s proof of the capacity of the pentagon was implicitly contained (but unnoticed!) in the works of Jelinek and Gallager on the expurgated bound done at least ten years before Lovasz. In the opposite direction, new upper bounds on the reliability function are derived for channels with an odd number of inputs by using an adaptation of Delsarte’s linear programming bound. First, we derive a bound based on the minimum distance, which combines Lovasz’s construction for bounding the graph capacity with the McEliece-Rodemich-Rumsey-Welch construction for bounding the minimum distance of codes in the Hamming space. Then, for the particular case of cross-over probability 1/2, we derive an improved bound by also using the method of Kalai and Linial to study the spectrum distribution of codes.
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bounds on the reliability of a Typewriter channel
International Symposium on Information Theory, 2016Co-Authors: Marco Dalai, Yury PolyanskiyAbstract:We give new bounds on the reliability function of a Typewriter channel with 5 inputs and crossover probability 1/2. The lower bound is more of theoretical than practical importance; it improves very marginally the expurgated bound, providing a counterexample to a conjecture on its tightness by Shannon, Gallager and Berlekamp which does not need the construction of algebraic-geometric codes previously used by Katsman, Tsfasman and Vladuţ. The upper bound is derived by using an adaptation of the linear programming bound and it is essentially useful as a low-rate anchor for the straight line bound.
