Structured Random Linear Codes (SRLC): Bridging the Gap between Block and Convolutional Codes

Several types of AL-FEC (Application-Level FEC) codes for the Packet Erasure Channel exist. Random Linear Codes (RLC), where redundancy packets consist of random linear combinations of source packets over a certain finite field, are a simple yet efficient coding technique, for instance massively used for Network Coding applications. However the price to pay is a high encoding and decoding complexity, especially when working on $GF(2^8)$, which seriously limits the number of packets in the encoding window. On the opposite, structured block codes have been designed for situations where the set of source packets is known in advance, for instance with file transfer applications. Here the encoding and decoding complexity is controlled, even for huge block sizes, thanks to the sparse nature of the code and advanced decoding techniques that exploit this sparseness (e.g., Structured Gaussian Elimination). But their design also prevents their use in convolutional use-cases featuring an encoding window that slides over a continuous set of incoming packets. In this work we try to bridge the gap between these two code classes, bringing some structure to RLC codes in order to enlarge the use-cases where they can be efficiently used: in convolutional mode (as any RLC code), but also in block mode with either tiny, medium or large block sizes. We also demonstrate how to design compact signaling for these codes (for encoder/decoder synchronization), which is an essential practical aspect.Comment: 7 pages, 12 figure

Surface Tension Measurement of Low GWP Refrigerant Mixture HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32

HFOs (hydro-fluoro-olefins), HFO-1123 and HFO-1234ze(E) with GWP (global warming potential) of less than 1 attracted attention in a field of air conditioning and refrigeration engineering. However, the use of those HFO alone in such heat pump systems lucks adequate capacity or chemical stability. To compensate the shortcomings, mixtures coupled with R32 is considered to be one solution. This paper presents the surface tension measurement data of HFC-32, HFO-1123, and HFO-1234ze(E), and also their binary mixtures HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32 at various mass fractions. The capillary constant and surface tension of those are measured across temperature range from 267 K to 307 K using a measuring apparatus based on the differential capillary rise method to discuss the effects of mass fraction to the surface tension of HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32. The propagated uncertainty in the surface tension is typically 0.3 mN m-1. The experimentally quantified surface tension of HFC-32 alone well agrees with the calculated value of REFPROP ver. 9.1, and also data in literatures. However, data of HFO-1234ze(E) showed slightly negative deviation to REFPROP. To the authors’ best knowledge, available data for HFO-1123 was not found and presented data are new, so far. Among the selected predicting methods, the correlations of Di Nicola et al. (2011) and Gharagheizi et al. (2012) show the best agreement with data of two HFOs. The measured surface tension data of HFO-1123/HFC-32 at a HFC-32 mass fraction of 0.48 well agree with the correlation of Di Nicola et al. (2017). However, the correlation deviates from the present data as mass fraction approaches to 0 and 1. Similarly, data of HFO-1234ze(E)/HFC-32 shows considerable deviations

Multi-Cycle Test with Partial Observation on Scan-Based BIST Structure

Field test for reliability is usually performed with small amount of memory resource, and it requires a new technique which might be somewhat different from the conventional manufacturing tests. This paper proposes a novel technique that improves fault coverage or reduces the number of test vectors that is needed for achieving the given fault coverage on scan-based BIST structure. We evaluate a multi-cycle test method that observes the values of partial flip-flops on a chip during capture-mode. The experimental result shows that the partial observation achieves fault coverage improvement with small hardware overhead than the full observation.2011 Asian Test Symposium (ATS), 20-23 Nov. 2011, New Delhi, Indi

Not so random RLC AL-FEC codes

IETF 88 meeting, NWCRG (Network Coding) research group of the IRTF.International audienceThis document introduces a class of linear codes, derived from Random Linear Codes (RLC), mixing binary and non binary coefficients, as well as a particular structure. The goal is to define highly efficient erasure codes to be used in both sliding/elastic encoding window mode and block code mode

Simple Reed-Solomon Forward Error Correction (FEC) Scheme for FECFRAME, RFC 6865

This document describes a fully-specified simple Forward Error Correction (FEC) scheme for Reed-Solomon codes over the finite field (also known as the Galois Field) GF(2^^m), with 2 <= m <= 16, that can be used to protect arbitrary media streams along the lines defined by FECFRAME. The Reed-Solomon codes considered have attractive properties, since they offer optimal protection against packet erasures and the source symbols are part of the encoding symbols, which can greatly simplify decoding. However, the price to pay is a limit on the maximum source block size, on the maximum number of encoding symbols, and a computational complexity higher than that of the Low-Density Parity Check (LDPC) codes, for instance

Structured RLC codes: an update

International audienceThis document introduces a class of linear codes, derived from Random Linear Codes (RLC), mixing binary and non binary coefficients, as well as a particular structure. The goal is to define highly efficient erasure codes to be used in both sliding/elastic encoding window mode and block code mode

Different clinical effect of four antidementia drugs for Alzheimer's disease patients depending on white matter severity

AIM:To examine the clinical effect of four antidementia drugs (donepezil, galantamine, rivastigmine and memantine) in Alzheimer's disease patients who were divided into subgroups based on their periventricular hyperintensity (PVH) severity. METHODS: A total of 551 Alzheimer's disease patients (201 men and 350 women) were divided into four subgroups based on their PVH severity (0-III). They received monotherapy for 12 months. We compared the clinical effects at the baseline, and at 3, 6 and 12 months after initiation. RESULTS: The baseline age became higher with PVH grades, and the Mini-Mental State Examination and Hasegawa Dementia Scale-Revised showed a decrease that was dependent on white matter severity. Although the PVH 0 subgroup showed stable cognitive, affective and ADL functions until 12 months in all four drug groups, the PVH I subgroup showed an improved Apathy Scale from the baseline in response to memantine at 3 and 9 months (P < 0.05), and galantamine at 9 months (P < 0.01). In the PVH II subgroup, the Mini-Mental State Examination showed a significant improvement from the baseline in response to galantamine (P < 0.05) at 9 months and Hasegawa Dementia Scale-Revised (P < 0.05) at 3 months. In the PVH III subgroup, cognitive and affective functions were preserved in all four drug groups until 12 months, but activities of daily living deteriorated in the riverstigmine group at 6 and 12 months (P < 0.05). CONCLUSIONS: The present study shows that these four drugs showed sensitivity dependent on white matter severity that clinically affected cognitive, affective and activities of daily living functions. Geriatr Gerontol Int 2017; 17: 1991-1999

『議会開催要領』Modus Tenendi Parliamentum (A Manner of Holding a Parliament)とイングランド議会史

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