Pilot Design for Enhanced Channel Estimation in Doubly Selective Channels

This paper investigates pilot design for enhanced channel estimation in single carrier communication systems over doubly-selective channels (DSC). Our contribution is twofold: first, we propose to use Huffman sequences as pilot clusters with low peak-to-average power ratio (PAPR), yet with good channel estimation performance when periodic pilot placement is adopted; second, we propose a low-complexity pilot placement strategy based on the analysis of the complex-exponential basis expansion model (CE-BEM) of the DSC. The latter leads to improved channel estimation performance with useful insights for pilot placement

Pilot design for channel estimation in Doubly Selective Channel

We consider pilot sequence designs for channel estimation in doubly-selective channels (DSC) which are modeled using the basis expansion model (BEM) approach. We propose to use pilot sequences (instead of impulse pilots) to reduce the peak-to-average power ratio (PAPR) of the transmitted signal. Specifically, by analysing the mean square error (MSE) metric of the BEM channel coefficients, we propose the use of Huffman sequences to reduce the PAPR during channel estimation. Furthermore, we show that a systematic re-arrangement of the pilot sequence within the transmission frame can significantly improve the channel estimation performance of the system, as compared to the conventional periodic pilot placement

BP-based sparse graph list decoding of polar codes

How to construct an effective polar decoding scheme has attracted researchers in the field of communication. The belief propagation list (BPL) decoder has performance improvement over the traditional BP decoder but comes with much higher complexity. To solve the issue of high complexity & latency, a low-density parity-check (LDPC) like BP decoder was proposed but it suffered from performance degradation over the original BP decoder. In this letter, a BP-based sparse graph list (BP-SGL) decoder is proposed by leveraging both list decoding scheme and LDPC-like BP decoding algorithm to achieve performance improvement while maintaining low complexity & latency. The key idea of the proposed list generation method is the similarity comparison of decoding graphs. Testing results verify that selecting graphs with large structural differences helps to construct a list with good overall performance. Simulation results show that the proposed scheme is superior to LDPC-like BP, and even outperforms the original BPL and some state-of-the-art (SOTA) BP-based decoding algorithms with significant reduction in complexity & latency.National Research Foundation (NRF)This work was supported by the National Research Foundation under its Future Communications Research & Development Programme Grant Nos. FCP-NTU-RG-2022-020

Tissues and hair residues and histopathology in wild rats (Rattus rattus L.) and Algerian mice (Mus spretus Lataste) from an abandoned mine area (Southeast Portugal)

Data gathered in this study suggested the exposure of rats and Algerian mice, living in an abandoned mining area, to a mixture of heavy metals. Although similar histopathological features were recorded in the liver and spleen of both species, the Algerian mouse has proved to be the strongest bioaccumulator species. Hair was considered to be a good biological material to monitor environmental contamination of Cr in rats. Significant positive associations were found between the levels of this element in hair/kidney (r = 0.826, n = 9, p < 0.01) and hair/liver (r = 0.697, n = 9, p = 0.037). Although no association was found between the levels of As recorded in the hair and in the organs, the levels of this element recorded in the hair, of both species, were significantly higher in animals captured in the mining area, which met the data from the organs analysed. Nevertheless, more studies will be needed to reduce uncertainty about cause-effect relationships.http://www.sciencedirect.com/science/article/B6VB5-4GWBF4X-3/1/f46c8712ad59f76524c8d09b98929f4

Estimation of Spatial-Temporal Gait Parameters Using a Low-Cost Ultrasonic Motion Analysis System

In this paper, a low-cost motion analysis system using a wireless ultrasonic sensor network is proposed and investigated. A methodology has been developed to extract spatial-temporal gait parameters including stride length, stride duration, stride velocity, stride cadence, and stride symmetry from 3D foot displacements estimated by the combination of spherical positioning technique and unscented Kalman filter. The performance of this system is validated against a camera-based system in the laboratory with 10 healthy volunteers. Numerical results show the feasibility of the proposed system with average error of 2.7% for all the estimated gait parameters. The influence of walking speed on the measurement accuracy of proposed system is also evaluated. Statistical analysis demonstrates its capability of being used as a gait assessment tool for some medical applications

Genomics of hybrid poplar (Populus trichocarpa x deltoides) interacting with; forest tent caterpillars (Malacosoma disstria): normalized and full-length cDNA libraries, expressed sequence tags, and a cDNA microarray for the study of insect-induced defences in poplar

As part of a genomics strategy to characterize inducible defences against insect herbivory in poplar, we developed a comprehensive suite of functional genomics resources including cDNA libraries, expressed sequence tags (ESTs) and a cDNA microarray platform. These resources are designed to complement the existing poplar genome sequence and poplar (Populus spp.) ESTs by focusing on herbivore- and elicitor-treated tissues and incorporating normalization methods to capture rare transcripts. From a set of 15 standard, normalized or full -length cDNA libraries, we generated 139 007 3'- or 5'-end sequenced ESTs, representing more than one-third of the c. 385 000 publicly available Populus ESTs. Clustering and assembly of 107 519 3'-end ESTs resulted in 14 451 contigs and 20 560 singletons, altogether representing 35 011 putative unique transcripts, or potentially more than three-quarters of the predicted c. 45 000 genes in the poplar genome. Using this EST resource, we developed a cDNA microarray containing 15 496 unique genes, which was utilized to monitor gene expression in poplar leaves in response to herbivory by forest tent caterpillars (Malacosoma disstria). After 24 h of feeding, 1191 genes were classified as up-regulated, compared to only 537 down-regulated. Functional classification of this induced gene set revealed genes with roles in plant defence (e.g. endochitinases, Kunitz protease inhibitors), octadecanoid and ethylene signalling (e.g. lipoxygenase, allene oxide synthase, 1 -aminocyclopropane-1-carboxylate oxidase), transport (e.g. ABC proteins, calreticulin), secondary metabolism [e.g. polyphenol oxidase, isoflavone reductase, (-)-germacrene D synthase] and transcriptional regulation [e.g. leucine-rich repeat transmembrane kinase, several transcription factor classes (zinc finger C3H type, AP2/EREBP, WRKY, bHLH)]. This study provides the first genome-scale approach to characterize insect-induced defences in a woody perennial providing a solid platform for functional investigation of plant -insect interactions in poplarNRC publication: Ye