A long-standing discrepancy between experimental and theoretical values for the lifetimes of holes in surface-state electron bands on noble metal surfaces is resolved; previous determinations both are found to have been error. The ability scanning tunneling microscope verify surface quality before taking spectroscopic measurements used remove effects defect scattering lifetimes, a significant contribution prior determinations. treatment inelastic electron-electron developed that explicitly...

This paper proposes a network coding approach to cooperative diversity featuring the algebraic superposition of channel codes over finite field. The scenario under consideration is one in which two ldquopartnersrdquo - node A and B cooperate transmitting information single destination; each partner transmits both locally generated relayed that originated at other partner. key observation already knows A's (because it B) can exploit knowledge when decoding local information. leads an encoding...

We show that polar codes asymptotically achieve the whole capacity-equivocation region for wiretap channel when wiretapper's is degraded with respect to main channel, and weak secrecy notion used. Our coding scheme also achieves capacity of physically receiver-orthogonal relay channel. simulation results moderate block length binary erasure comparing two edge type LDPC codes.

Large matrix multiplications are central to large-scale machine learning applications. These operations often carried out on a distributed computing platform with master server and multiple workers in the cloud operating parallel. For such platforms, it has been recently shown that coding over input data matrices can reduce computational delay, yielding trade-off between recovery threshold, i.e., number of required recover product, communication load, total amount be downloaded from workers....

This paper describes techniques to decompose LT codes (a class of rateless erasure-correcting codes) into distributed (DLT) codes. DLT can be used independently encode data from multiple sources in a network such way that, when the DLT-encoded packets are combined at common relay, resulting bit stream (called modified (MLT) code) has degree distribution approximating that an code, with simulations indicating comparable performance. In essence, designed so final stage encoding for erasure...

We propose relaying strategies for uncoded two-way relay channels, where two terminals transmit simultaneously to each other with the help of a relay. In particular, we consider memoryless system, signal transmitted by is obtained applying an instantaneous function previously received signal. For binary antipodal signaling, class so called absolute (abs)-based schemes proposed in which processing at solely based on value analyze and optimize symbol-error performance existing new abs-based...

We investigate the design of network codes for multiple-user multiple-relay (MUMR) wireless networks with slow fading (quasi-static) channels. In these networks, M users have independent information to be transmitted a common base station (BS) help N relays, where ≥ 2 and 1 are arbitrary integers. such in terms diversity order measure asymptotic performance. For orthogonal channels, we show that based on maximum distance separable (MDS) can achieve N+1. further MDS coding construction is...

Since the discovery of turbo codes 20 years ago and subsequent rediscovery low-density parity check a few later, field channel coding has experienced number major advances. Until that time, code designers were usually happy with performance came within decibels Shannon Limit, primarily due to implementation complexity constraints, whereas new techniques now allow small fraction decibel capacity modest encoding decoding complexity. Due these significant improvements, standards in applications...

A secret sharing scheme is a method to store information securely and reliably. Particularly, in threshold scheme, encoded into n shares, such that any set of at least t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> shares suffice decode the secret, most xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> <; reveal no about secret. Assuming each party holds share user wishes by receiving from parties; question we study how minimize...

The calculation of nonbinary extrinsic information transfer charts for the iterative decoding concatenated index-based codes is addressed. We show that at output a constituent posteriori probability decoder can be calculated with very low complexity, where expensive histogram measurements are not required any more. An example turbo trellis-coded modulation demonstrates capabilities proposed approach

We consider relaying strategies for two-way relay channels, where two terminals transmits simultaneously to each other with the help of relays. A memoryless system is considered, signal transmitted by a depends only on its last received signal. For binary antipodal signaling, we analyze and optimize performance existing amplify forward (AF) absolute (abs) decode (ADF) two- way AWGN channels. new abs-based AF (AAF) scheme proposed, which has better than AF. In low SNR, AAF performs even ADF....

Theoretical calculations and scanning-tunneling spectroscopy measurements of the hole lifetime broadening, ${\ensuremath{\tau}}^{\ensuremath{-}1},$ in a quantum-well state for 0.95 1.0 monolayers Na on Cu(111) are reported. A model potential is proposed calculating states monolayer metal surfaces. The inelastic electron-electron contribution, ${\ensuremath{\tau}}_{e\ensuremath{-}e}^{\ensuremath{-}1},$ evaluated within $\mathrm{GW}$ approximation by using eigenfunctions eigenenergies obtained...

The electronic structure of artificial Mn atom arrays on Ag(111) is characterized in detail with scanning tunnelling spectroscopy and spectroscopic imaging at low temperature. We demonstrate the degree to which variations geometry may be used control spatial spectral distributions surface state electrons confined within arrays, how these are influenced by atoms placed ability induce features specific energies exploited through lineshape analyses deduce quasiparticle lifetimes near Fermi...

This paper proposes a new approach to channel code design for wireless network applications. The resulting nested codes can be decoded at different effective rates by receivers-rates that depend on the prior knowledge possessed each receiver; we say these have multiple interpretations. We identified several applications in networks where this property is useful. Specific constructions as well efficient soft and hard decision decoding algorithms are described. concept of with interpretations...

The secrecy capacity of a network, for given collection permissible wiretap sets, is the maximum rate communication such that observing links in any set reveals no information about message. This paper considers secure network coding with nonuniform or restricted example, networks unequal link capacities where wiretapper can subset $k$ links, only be wiretapped. Existing results show case uniform sets (networks equal links/packets wiretapped), by cut-set bound, and achieved injecting random...

In this work, we first provide the definition of absorbing sets for linear channel codes over non-binary alphabets. a graphical representation code, an set can be described by collection topological and edge labeling conditions. case, equations relating neighboring variable check nodes are field, weights given non-zero elements that field. As consequence, it becomes more difficult structure to satisfy constraints compared binary case. This observation in part explains superior performance...

Tensor operations, such as matrix multiplication, are central to large-scale machine learning applications. These operations can be carried out on a distributed computing platform with master server at the user side and multiple workers in cloud operating parallel. For platforms, it has been recently shown that coding over input data matrices reduce computational delay, yielding tradeoff between recovery threshold communication load. In this work, we impose an additional security constraint...

We study the problem of private function retrieval (PFR) in a distributed storage system. In PFR user wishes to retrieve linear combination M messages stored non-colluding (N, K) MDS coded databases while revealing no information about coefficients intended any individual databases. present an achievable scheme for with rate that matches capacity derived recently, R = (1+R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> +R <sup...

Coded elastic computing, introduced by Yang et al. in 2018, is a technique designed to mitigate the impact of elasticity cloud computing systems, where machines can be preempted or added during rounds. This approach utilizes maximum distance separable (MDS) coding for both storage and download matrix-matrix multiplications. The proposed scheme unable tolerate stragglers has high encoding complexity upload cost. In 2023, we addressed these limitations employing uncoded Lagrange-coded...

Coded elastic computing enables virtual machines to be preempted for high-priority tasks while allowing new join ongoing computation seamlessly. This paper addresses coded matrix-matrix multiplications with straggler tolerance by encoding both storage and download using Lagrange codes. In 2018, Yang et al. introduced the first scheme multiplications, achieving a lower computational load requirement. However, this lacks suffers from high upload cost. Zhong (2023) later tackled these...

The tunneling current of a scanning microscope is reported to cause light emission from the metallic quantum well system Na on Cu(111). Optical spectra along with spectroscopy show that one component due interband transitions between states layer. other similar plasmon-mediated observed previously noble metals. unique local probe electronic structure this system.

Scanning tunneling spectroscopy of p(2 x 2) Cs and Na ordered overlayers on Cu(111) reveals similar line widths quasi-two-dimensional quantum well states despite largely different binding energies. Detailed calculations show that 50% the are due to electron-phonon scattering while inelastic electron-electron is negligible. The mechanism enhanced elastic Brillouin zone backfolding contributes remaining width.

We present a novel symbol-based soft-input posteriori probability (APP) decoder for packetized variable-length encoded source indexes transmitted over wireless channels where the residual redundancy after encoding is exploited error protection. In combination with mean-square or maximum APP estimation of reconstructed data, whole decoding process close to optimal. Furthermore, solutions proposed reduced complexity are discussed and compared near-optimal solution. When, in addition, channel...

We propose efficient coding schemes for two communication settings: 1) asymmetric channels and 2) with an informed encoder. These settings are important in non-volatile memories, as well optical broadcast communication. The based on non-linear polar codes, they build improve recent work these settings. In channels, we tackle the exponential storage requirement of previously known that resulted from use large Boolean functions. improved scheme achieves capacity polynomial computational...

Bandwidth efficient parallel-concatenated Turbo Trellis Coded Modulation (TTCM) schemes were designed for communicating over uncorrelated Rayleigh fading channels. A symbol-based union bound was derived analysing the error floor of proposed TTCM schemes. pair In-phase (I) and Quadrature-phase (Q) interleavers employed interleaving I Q components coded symbols, in order to attain an increased diversity gain. The decoding convergence IQ-TTCM analysed using EXtrinsic Information Transfer (EXIT)...