We propose a general method for constructing Tanner graphs having large girth by establishing edges or connections between symbol and check nodes in an edge-by-edge manner, called progressive edge-growth (PEG) algorithm. Lower bounds on the of PEG minimum distance resulting low-density parity-check (LDPC) codes are derived terms parameters graphs. Simple variations algorithm can also be applied to generate linear-time encodeable LDPC codes. Regular irregular using allowing take values over...

Various log-likelihood-ratio-based belief-propagation (LLR-BP) decoding algorithms and their reduced-complexity derivatives for low-density parity-check (LDPC) codes are presented. Numerically accurate representations of the check-node update computation used in LLR-BP described. Furthermore, approximate computations shown to achieve a reduction complexity by simplifying update, or symbol-node both. In particular, two main approaches simplified updates presented that based on so-called...

We propose a general method for constructing Tanner (1981) graphs with large girth by progressively establishing edges or connections between symbol and check nodes in an edge-by-edge manner, called progressive edge-growth (PEG) construction. Lower bounds on the minimum distance of resulting low-density parity-check (LDPC) codes are derived terms parameters graphs. Encoding LDPC based PEG principle is also investigated. show how to exploit graph construction obtain that allow linear time...

Write amplification is a critical factor limiting the random write performance and endurance in storage devices based on NAND-flash memories such as solid-state drives (SSD). The impact of garbage collection influenced by level over-provisioning choice reclaiming policy. In this paper, we present novel probabilistic model for log-structured flash-based SSDs. Specifically, quantify analytically simulation assuming workloads uniformly-distributed short writes. Moreover, propose modified...

Efficient implementations of the sum-product algorithm (SPA) are presented for decoding low-density parity-check (LDPC) codes using log-likelihood ratios (LLR) as messages between symbol and nodes. Various reduced-complexity derivatives LLR-SPA proposed. Both serial parallel investigated, leading to trellis tree topologies, respectively. Furthermore, by exploiting inherent robustness LLRs, it is shown, via simulations, that coarse quantization tables sufficient implement complex core...

The proton exchange membrane fuel cell (PEMFC) is a fast growing next-generation energy conversion technology, which has broad application prospects in electric vehicles, such as portable power supplies, fixed and the military industry. development of PEMFCs attracted much attention due to their high efficiency, good low-temperature startup performance, no pollution, noise, other advantages. However, cathodic oxygen reduction reaction (ORR) kinetics cells slow. It therefore necessary that we...

Abstract Solid‐state lithium‐sulfur batteries (SSLSBs) using polymer electrolytes are considered as one of the most promising energy storage systems due to their high specific energy, facile processability, and low cost. However, sluggish solid‐state sulfur conversion kinetics limits density challenges practical application. Here, address this concern, a hollow carbon/Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 nanosphere (H‐C/LATP) structure is prepared, with mixed electronic/ionic conductivity, hosts...

Low-density parity-check (LDPC) codes in their broader-sense definition are linear whose matrices have fewer 1s than 0s. Finding minimum distance is therefore general an NP-hard problem. We propose a randomized algorithm called nearest nonzero codeword search (NNCS) approach to tackle this problem for iteratively decodable LDPC codes. The principle of the NNCS codewords locally around all-zero perturbed by minimal noise, anticipating that resultant will most likely contain minimum-Hamming-...

Today's data storage systems are increasingly adopting low-cost disk drives that have higher capacity but lower reliability, leading to more frequent rebuilds and a risk of unrecoverable media errors. We propose an efficient intradisk redundancy scheme enhance the reliability RAID systems. This introduces additional level inside each disk, on top across multiple disks. The parity provides protection against failures, whereas proposed aims protect media-related In particular, we consider...

Abstract Poly(ethylene oxide) (PEO)‐based solid‐state lithium‐sulfur batteries (SSLSBs) have garnered considerable attention as potential energy storage solutions owing to their exceptional specific energy, ease of processing, and economic viability. Nevertheless, the inherently low Li + conductivity PEO electrolyte inevitable dissolution lithium polysulfides (LiPSs) within sulfur cathode hinder conversion kinetics lead significant loss active materials, thus posing challenges for practical...

We derive the average symbol and Hamming weight spectrum functions of random ensemble regular low-density parity-check (LDPC) codes over GF(2/sup b/) when used with binary-input noisy channel. This work confirms theoretically that near-Shannon-limit performance Gallager's binary LDPC can be significantly enhanced by moving to fields higher order. construct a family error-correcting based on representation defined cycle Tanner graph appears "good" for both optimum iterative decoding In...

Background Compressed sensing (CS) has been widely used to improve the speed of MRI, but feasibility application in 3D intracranial MR angiography (MRA) needs be evaluated clinical practice. Purpose To evaluate CS‐MRA comparison with conventional 3D‐MRA (Con‐MRA). Study Type Retrospective. Subjects Forty‐nine consecutive patients suspected arterial disease. Field Strength/Sequence 3T MRI. time‐of‐flight (TOF) MRA using a CS algorithm and TOF scan. Assessment Three radiologists (4, 11, 12...

Two schemes proposed to cope with unrecoverable or latent media errors and enhance the reliability of RAID systems are examined. The first scheme is established, widely used disk scrubbing scheme, which operates by periodically accessing drives detect media-related errors. These subsequently corrected rebuilding sectors affected. second recently intradisk redundancy uses a further level inside each disk, in addition across multiple disks. Analytic results obtained assuming Poisson arrivals...

A novel boosting extreme learning machine is proposed for near-infrared spectral quantitative analysis which greatly enhances predictive accuracy and stability.

Two schemes proposed to cope with unrecoverable or latent media errors and enhance the reliability of RAID systems are examined. The first scheme is established, widely used, disk scrubbing scheme, which operates by periodically accessing drives detect media-related errors. These subsequently corrected rebuilding sectors affected. second recently intradisk redundancy uses a further level inside each disk, in addition across multiple disks. A new model developed evaluate extent reduces sector...

Superionic halides have aroused interests in field of solid electrolytes such as Li

A general method for constructing Tanner graphs having a large girth by progressively establishing edges between symbol and check nodes in an edge-by-edge manner, called progressive edge-growth (PEG) construction, is proposed. Such approach powerful generating good regular irregular LDPC codes of short moderate block lengths.

This paper presents a data-placement scheme for log-structured flash translation layers (FTLs), with the dual aims of reducing write amplification due to garbage collection and wear-out block erasing programming. The central idea is identify place data that expected change frequently together in young blocks are far from wearing out, infrequently changing old where it can be stay longer. In previous work, wear levelling were treated separately, importance placement was largely ignored. We...

Replication is a widely used method to protect large-scale data storage systems from loss when nodes fail. It well known that the placement of replicas different blocks across affects time rebuild. Several described in literature are designed based on premise minimizing rebuild times maximizes system reliability. Our results however indicate reliability essentially unaffected by replica scheme. We show that, for replication factor two, all possible schemes have mean (MTTDLs) within two...

Principal component analysis is a versatile tool to reduce dimensionality which has wide applications in statistics and machine learning. It particularly useful for modeling data high-dimensional scenarios where the number of variables p comparable to, or much larger than sample size n. Despite an extensive literature on this topic, researchers have focused static principal eigenvectors, are not suitable stochastic processes that dynamic nature. To characterize change entire course...

This dissertation presents a systematic exposition on finite-block-length coding theory and practice. We begin with the task of identifying maximum achievable rates over noisy, constrained channels, referred to as (e, n)-capacity Cen, e denoting target block-error probability n block length. characterize how optimum codes look like channels. Constructing good, short-block-length error-correcting defined sparse graphs is focus thesis. propose new, general method for constructing Tanner having...