IEEE/CAM Information Theory Workshop at Cornell最新文献

Stochastic Representations of Formal Languages 形式语言的随机表示

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761438

M.I. Miller

引用次数: 0

Connections between exponential sums, algebraic curves and sequence design 指数和之间的联系，代数曲线和序列设计

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761397

P. Kumar, O. Moreno

引用次数: 0

Large Multiuser Detection in Code Division Multiple Access Communication 码分多址通信中的大用户检测

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761412

B. Aazhang

引用次数: 0

A Comparison of Trellis Coded SSMA to Convolutionally Coded SSMA 网格编码SSMA与卷积编码SSMA的比较

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761413

G. Boudreau, D. Falconer, S. Mahmoud

引用次数: 0

Error Probability of CDMA in the Poisson Channel 码分多址在泊松信道中的错误概率

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761414

D. Brady, S. Verdú

{"title":"Error Probability of CDMA in the Poisson Channel","authors":"D. Brady, S. Verdú","doi":"10.1109/ITW.1989.761414","DOIUrl":"https://doi.org/10.1109/ITW.1989.761414","url":null,"abstract":"Recent work in the analysis of noncoherent, optical Code Division Multiple Access (CDMA) receivers has relied on the approximations of Gaussian-distributed Multiple Access Interference (MAI). cooperation among the users for chip synchronization, or direct observation of the optical intensity (also known as perfect-optical-to-electrical conversion). Until now.the accuracy of these approximations has not been addressed. In this work we derive the exact error expression for the noncoherent, optical matched-filter receiver based on the electron count in a symbol period. The analysis is valid for arbitrary quantum efficiencies and dark currents, and employs the semi-classical model of light. We do not assume perfect optical-to-electrical conversion, Gaussian-distributed MAI, or synchronism among the users. We then compare the exact error rate to those obtained from popular approximations. Using the prime codes as an example, we show that the assumption of perfect optical-to-electrical conversion, which leads to the \"error-free\" hypothesis test for a suitably small user group size, is a poor model for the photodetection process at moderate incident optical intensities and dark currents. We show that the combined assumptions of perfect optical-to-electrical conversion and Gaussian-distributed MA1 yield an overestimate of the optimal threshold and an underestimate of the error rate for small but reasonable optical powers. The error rate expression that we derive is valid for arbitrary, i.i.d. relative delays among the users. The error rate expression is considerably simplified when the delay distribution corresponding to chip-synchronism is used. We take advantage of this fact to derive upper and lower bounds on the asynchronous error rate by using the chip-synchronous expression. The tightness of these bounds for various optical energies and signature sequence sets is discussed.","PeriodicalId":413028,"journal":{"name":"IEEE/CAM Information Theory Workshop at Cornell","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114612999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Zero-error problems in information theory 信息论中的零误差问题

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761407

J. Korner, G. Symonyi

引用次数: 0

On-Chip ECC for Multi-Level Random Access Memories 片上ECC多级随机存取存储器

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761433

R. Goodman, M. Sayano

{"title":"On-Chip ECC for Multi-Level Random Access Memories","authors":"R. Goodman, M. Sayano","doi":"10.1109/ITW.1989.761433","DOIUrl":"https://doi.org/10.1109/ITW.1989.761433","url":null,"abstract":"In this talk we investigate a number of on-chip coding techniques for the protection of Random Access Memories which use multi-level as opposed to binary storage cells. The motivation for such RAM cells is of course the storage \u0000of several bits per cell as opposed to one bit per cell [l]. \u0000Since the typical number of levels which a multi-level RAM can handle is 16 (the cell being based on a standard DRAM \u0000cell which has varying amounts of voltage stored on \u0000it) there are four bits recorded into each cell [2]. The disadvantage of multi-level RAMs is that they are much \u0000more prone to errors, and so on-chip ECC is essential for reliable operation. There are essentially three reasons for error control coding in multi-level RAMs: To \u0000correct soft errors, to correct hard errors, and to \u0000correct read errors. The source of these errors is, \u0000respectively, alpha particle radiation, hardware faults, and \u0000data level ambiguities. On-chip error correction can be \u0000used to increase the mean life before failure for all three types of errors. Coding schemes can be both bitwise and \u0000cellwise. Bitwise schemes include simple parity checks and SEC-DED codes, either by themselves or as product codes \u0000[3]. Data organization should allow for burst error correction, since alpha particles can wipe out all \u0000four bits in a single cell, and for dense memory chips, \u0000data in surrounding cells as well. This latter effect becomes more serious as feature sizes are scaled, and \u0000a single alpha particle hit affects many adjacent cells. Burst codes such as those in [4] can be used to correct for \u0000these errors. Bitwise coding schemes are more efficient \u0000in correcting read errors, since they can correct single bit \u0000errors and allow the remaining error correction power to be \u0000used elsewhere. Read errors essentially affect one bit \u0000only, since the use of Grey codes for encoding the bits \u0000into the memory cells ensures that at most one bit is flipped with each successive change in level. Cellwise schemes include Reed-Solomon codes, hexadecimal \u0000codes, and product codes. However, simple encoding and decoding algorithms are necessary, since excessive space taken by powerful but complex encoding/decoding circuits can \u0000be offset by having more parity cells and using simpler \u0000codes. These coding techniques are more useful for correcting hard and soft errors which affect the entire cell. They tend to be more complex, and they are not as \u0000efficient in correcting read errors as the bitwise codes. \u0000In the talk we will investigate the suitability and \u0000performance of various multi-level RAM coding schemes, \u0000such as row-column codes, burst codes, hexadecimal codes, Reed-Solomon codes, concatenated codes, and some new majority-logic decodable codes. In particular we investigate their tolerance to soft errors, and to feature size scaling.","PeriodicalId":413028,"journal":{"name":"IEEE/CAM Information Theory Workshop at Cornell","volume":"186 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123355499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Trellis Coding for the Magnetic Storage Channel 磁存储通道的栅格编码

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761426

W. Abbott, J. Cioffi

引用次数: 0

Estimating the Model Order in Exponential Families 指数族中模型阶的估计

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761421

N. Merhav

{"title":"Estimating the Model Order in Exponential Families","authors":"N. Merhav","doi":"10.1109/ITW.1989.761421","DOIUrl":"https://doi.org/10.1109/ITW.1989.761421","url":null,"abstract":"The problem of estimating the model order of a statistical model has been widely studied in the literature of time series analysis, information theory and automatic control. Most of the known order estimation schemes (AIC, BIC, CAT, FPE, MDL, etc.), although based on reasonable ideas, are heuristic in the sense that no particular risk function (involving the true order and its estimate) is optimized. Rather, these methods are derived from various extensions of the maximum likelihood principle. In this talk, a new approach to the model order estimation problem is presented: Estimators are sought which accomplish higher exponential rate of decrease in the underestimation probability, while keeping the exponential rate of the overestimation probability at a certain prescribed level. This criterion, which is an extension to the Neyman-Pearson criterion, enables to control between overestimation and underestimation probabilities, in a way that is easy and well understood. For the class of statistical models from the exponential family, an order estimator is suggested and shown to be optimal in the above defined sense, that is, it provides the best tradeoff between the asymptotic exponential rates of overestimation and underestimation probabilities. The suggested method is strongly related to the gene-realized likelihood ratio test (GLRT), which is widely used for composite hypothesis testing problems. Several examples of specific models from the exponential family are given: The Gaussian linear regression model, the Gaussian autoregressive model, and the finite alphabet Markov model. It is also demonstrated that several well known composite hypothesis testing problems can be formalized in the model order estimation framework and then solved as special cases. The results generalize to models where there are more than one order to estimate (e.g. ARMA(p,q) model). It is demonstrated that the computation time is significantly smaller than those of other model order estimation schemes. Another direction of extending the results is that of estimating the number of states of a general finite-state source, which not necessarily belongs to the exponential family. An interesting relation between the proposed scheme and universal data compression schemes will be pointed out: It can be shown that efficient data compression algorithms can be used as tools for efficient order estimation in the above described approach.","PeriodicalId":413028,"journal":{"name":"IEEE/CAM Information Theory Workshop at Cornell","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116781526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Computational Capacity of Neurons with Binary Weights or, Why it is OK to be a Bit Neuron 二元权值神经元的计算能力，或者，为什么可以是位神经元

IEEE/CAM Information Theory Workshop at Cornell Pub Date : 1989-06-25 DOI: 10.1109/ITW.1989.761439

S. S. Venkatesh

{"title":"The Computational Capacity of Neurons with Binary Weights or, Why it is OK to be a Bit Neuron","authors":"S. S. Venkatesh","doi":"10.1109/ITW.1989.761439","DOIUrl":"https://doi.org/10.1109/ITW.1989.761439","url":null,"abstract":"synaptic weights prescribed in the algorithms might, at least for some applications, be an artifact of the algorithms used. Practical considerations in the building of hardware for these networks also dictate the study of the effect of imposing limited dynamic ranges on coefficients on computational capacity and learning in these neural network models. There are, hence, cogent theoretical and practical spurs to study networks with dynamic range limited synapses. We investigate two fundamental issues: Can we compute efficiently with these networks? Can constrained networks learn? Setting up a simple network model with binary weights, we argue that there is very little loss in eschewing real interconnections in favour of binary links. We demonstrate rigorously that the computational capacity scales gracefully when synaptic dynamic range is reduced from the continuum to a single bit: with binary connections the achievable capacity is as much as half that with real interconnections. Analogous results appear to hold for learning within the constraints of binary interconnections. Convergence rates for binary learning are reduced, but there is qualitative similarity to learning performance without constraints. While the actual mathematical demonstrations are quire involved, the algorithms themselves are quite simple and appeal persuasively to intuition. Based in part on the thesis that it is arguably easier to implement binary links than real interconnections, researchers have been building small prototype networks which appear to function reasonably we1L3 Our results appear to provide theoretical support for such ventures. It may be possible to generalise the results to other situations involving distributed","PeriodicalId":413028,"journal":{"name":"IEEE/CAM Information Theory Workshop at Cornell","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132525605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0