27,439 research outputs found
Erasure Insertion in RS-Coded SFH MFSK Subjected to Tone Jamming and Rayleigh Fading
No full textThe achievable performance of Reed Solomon (RS) coded slow frequency hopping (SFH) assisted M-ary frequency shift keying (MFSK) using various erasure insertion (EI) schemes is investigated, when communicating over uncorrelated Rayleigh fading channels in the presence of multitone jamming. Three different EI schemes are considered, which are based on the output threshold test (OTT), on the ratio threshold test (RTT) and on the joint maximum output-ratio threshold test (MO-RTT). The relevant statistics of these EI schemes are investigated mathematically and based on these statistics, their performance is evaluated in the context of error-and-erasure RS decoding. It is demonstrated that the system performance can be significantly improved by using error-and-erasure decoding invoking the EI schemes considered
Low complexity Erasure Insertion in RS-Coded SFH Spread-Spectrum Communications with Partial-Band Interference and Nakagami- Fading
No full textAbstract—In this paper we propose two novel low-complexity, low-delay erasure insertion schemes, namely, the output threshold test (OTT) and joint maximum output and ratio threshold Test (MO-RTT). The employment of the OTT and MO-RTT is beneficial in the context of the “errors-and-erasures” Reed–Solomon (RS) decoding in a slow frequency-hopping spread-spectrum (SFH/SS) system using -ary frequency-shift keying (MFSK). The statistics of the erasure insertion related decision variables associated with the OTT, MO-RTT as well as with the ratio threshold test (RTT) are investigated, when the channel of each frequency-hopping (FH) slot is modeled as flat Nakagamifading. The transmitted signals also experience both additive white Gaussian noise (AWGN) as well as partial-band Gaussian interference (PBGI). The properties of these erasure insertion schemes are investigated with the aid of their statistics. The performance of the proposed erasure insertion schemes and that of the erasure insertion scheme using the RTT is investigated and compared in the context of RS coded SFH/SS systems using MFSK. Furthermore, the performance of the RS coded SFH/SS systems is also compared both with and without side-information concerning the PBGI. Index Terms—Errors-and-erasures decoding, frequency-hopping, joint maximum output and ratio threshold test, M-ary frequency-shift keying, Nakagami fading, output threshold test, partial band interference, ratio threshold test, Reed–Solomon codes, spread-spectrum communications
Erasure Insertion in RS-Coded SFH MFSK Subjected to Tone Jamming and Rayleigh Fading
No full textThe achievable performance of Reed Solomon (RS) coded slow frequency hopping (SFH) assisted M-ary frequency shift keying (MFSK) using various erasure insertion (EI) schemes is investigated, when communicating over uncorrelated Rayleigh fading channels in the presence of multitone jamming. Three different EI schemes are considered, which are based on the output threshold test (OTT), on the ratio threshold test (RTT) and on the joint maximum output-ratio threshold test (MORTT). The relevant statistics of these EI schemes are investigated mathematically and based on these statistics, their performance is evaluated in the context of error-and-erasure RS decoding. It is demonstrated that the system performance can be significantly improved by using error-and-erasure decoding invoking the EI schemes considered. Index Terms—Tone jamming, OTT, RTT, MO-RTT, SFH, error-and-erasure decoding (EED)
#nowplaying-rs
No full text<p>The nowplaying-rs dataset features context- and content features of listening events. It contains 11.6 million music listening events of 139K users and 346K tracks collected from Twitter. The dataset comes with a rich set of item content features and user context features, as well as timestamps of the listening events. Moreover, some of the user context features imply the cultural origin of the users, and some others - like hashtags - give clues to the emotional state of a user underlying a listening event.</p>
<p>The dataset contains three files:</p>
<ul>
<li>user_track_hashtag_timestamp.csv contains basic information about each listening event. For each listening event, we provide an id, the user_id, track_id, hashtag, created_at </li>
<li>context_content_features.csv: contains all context and content features. For each listening event, we provide the id of the event, user_id, track_id, artist_id, content features regarding the track mentioned in the event (instrumentalness, liveness, speechiness, danceability, valence, loudness, tempo, acousticness, energy, mode, key) and context features regarding the listening event (coordinates (as geoJSON), place (as geoJSON), geo (as geoJSON), tweet_language, created_at, user_lang, time_zone, entities contained in the tweet).</li>
<li>sentiment_values.csv contains sentiment information for hashtags. It contains the hashtag itself and the sentiment values gathered via four different sentiment dictionaries: AFINN, Opinion Lexicon, Sentistrength Lexicon and vader. For each of these dictionaries we list the minimum, maximum, sum and average of all sentiments of the tokens of the hashtag (if available, else we list empty values). However, as most hashtags only consist of a single token, these values are equal in most cases. Please note that the lexica are rather diverse and therefore, are able to resolve very different terms against a score. Hence, the resulting csv is rather sparse. The file contains the following comma-separated values: <hashtag, vader_min, vader_max, vader_sum,vader_avg, afinn_min, afinn_max, afinn_sum, afinn_avg, ol_min, ol_max, ol_sum, ol_avg, ss_min, ss_max, ss_sum, ss_avg >, where we abbreviate all scores gathered over the Opinion Lexicon with the prefix 'ol'. Similarly, 'ss' stands for SentiStrength. </li>
</ul>
<p>Please note that user_track_hashtag_timestamp.csv and context_content_features.csv partly provide the same features. We deliberately chose to do so to be able to provide useable files that do not have to be matched and joined with each other to perform e.g., simple recommendation tasks.</p>
<p>Please also find the training and test-splits for the dataset in this repo. Also, Asmita provides prototypical implementations of a context-aware recommender system based on the dataset at https://github.com/asmitapoddar/nowplaying-RS-Music-Reco-FM.</p>
<p><br>
If you make use of this dataset, please cite the following paper where we describe and experiment with the dataset:</p>
<p>@inproceedings{smc18,<br>
title = {#nowplaying-RS: A New Benchmark Dataset for Building Context-Aware Music Recommender Systems},<br>
author = {Asmita Poddar and Eva Zangerle and Yi-Hsuan Yang},<br>
url = {http://mac.citi.sinica.edu.tw/~yang/pub/poddar18smc.pdf},<br>
year = {2018},<br>
date = {2018-07-04},<br>
booktitle = {Proceedings of the 15th Sound & Music Computing Conference},<br>
address = {Limassol, Cyprus},<br>
note = {code at https://github.com/asmitapoddar/nowplaying-RS-Music-Reco-FM},<br>
tppubtype = {inproceedings}<br>
}</p>
Non-Coherent Cooperative Communications Dispensing with Channel Estimation Relying on Erasure Insertion Aided Reed-Solomon Coded SFH M-ary FSK Subjected to Partial-Band Interference and Rayleigh Fading
No full textThe rationale of our design is that although much of the literature of cooperative systems assumes perfect coherent detection, the assumption of having any channel estimates at the relays imposes an unreasonable burden on the relay station. Hence, non-coherently detected Reed-Solomon (ReS) coded Slow Frequency Hopping (SFH) assisted M -ary Frequency Shift Keying (FSK) is proposed for cooperative wireless networks, subjected to both partial-band interference and Rayleigh fading. Erasure insertion (EI) assisted ReS decoding based on the joint maximum output-ratio threshold test (MO-RTT) is investigated in order to evaluate the attainable system performance. Compared to the conventional error-correction-only decoder, the EI scheme may achieve an Eb/N0 gain of approximately 3dB at the Codeword Error Probability, Pw , of 10-4 , when employing the ReS (31, 20) code combined with 32-FSK modulation. Additionally, we evaluated the system’s performance, when either equal gain combining (EGC) or selection combining (SC) techniques are employed at the destination’s receiver. The results demonstrated that in the presence of one and two assisting relays, the EGC scheme achieves gains of 1.5 dB and 1.0 dB at the Pw of 10-6 , respectively, compared to the SC arrangement. Furthermore, we demonstrated that for the same coding rate and packet size, the ReS (31, 20) code using EI decoding is capable of outperforming convolutional coding, when 32-FSK modulation is considered, whilst LDPC coding had an edge over the above two schemes
Minimum Mean-Square Error and Maximum Likelihood Multiuser Detection: Statistical Properties and Applications
Full text link'Errors-and-Erasures' decoding in RS coded DS-CDMA using noncoherent <i>M</i>-ary orthogonal modulation
No full textIn this contribution we investigate the performance of Reed-Solomon (RS) coded DS-CDMA using noncoherent M-ary orthogonal modulation over multipath Rayleigh fading channels. 'Errors-and-erasures' RS decoding is considered, where erasures are declared based on various erasure insertion schemes, such as the maximum Output Threshold Test (OTT), Ratio Threshold Test (RTT) and the joint Maximum Output and Ratio Threshold Test (MOR-TT). Furthermore, the performance of 'errors-and-erasures' decoding employing the joint MOR-TT is compared to that of 'error-correction-only' decoding and to that of 'errors-and-erasures' decoding using the OTT as well as the RTT. The numerical results show that, when using 'errors-and-erasures' decoding, RS codes of a given code rate can achieve a significantly higher coding gain than without erasure information, and that the MOR-TT technique outperforms both the RTT and the OTT techniques
'Errors-and-Erasures' decoding performance of RS coded DS-CDMA using <i>M</i>-ary orthogonal signalling
No full textIn this contribution we investigate the performance of RS coded DS-CDMA using M-ary orthogonal signalling over multipath Rayleigh fading channels. 'Errors-And-Erasures (EAE)' RS decoding is considered, where erasures are declared based on the joint Maximum Output and Ratio Threshold Test (MOR-TT). Two classes of diversity reception techniques suitable for noncoherent M-ary detection are invoked, namely either Equal Gain Combining (EGC) or Selection Combining (SC) and their related performance is evaluated for both uncoded and coded DS-CDMA systems. The performance of the proposed MOR-TT technique is compared to that of the Ratio Threshold Test (RTT) and the Output Threshold Test (OTT), as well as that of 'Error-Correction-Only (ECO)' decoding. The numerical results show that when using EAE decoding, RS codes of a given code rate are capable of achieving a Significantly higher coding gain than without erasure information. Furthermore, the MOR-TT technique outperforms both the RTT and the OTT techniques
On the bridging mechanism in vibration controlled dispensing of pharmaceutical powders from a micro hopper
No full textAccurate batch dispensing of pharmaceutical powders, on the scale of hundreds of microns, in small doses is a challenging task. A novel dispensing technique has been developed by Yang et al. using high-frequency vibration to control powder flowout of a narrow hopper. This method removes the need for mechanical valves because the powder, very quickly, forms a bridge-like structure across the passive outlet preventing outflow. Activation of the vibration has been found to destabilise the bridging structure enabling the powder to flow, when vibration stops the bridge structure quickly rebuilds and dispensing stops. In this work the Discrete Element Method (DEM) was used to simulate this novel dispensing control method in order to identify the internal mechanism that allows the flow to be controlled so precisely. A simulated conical hopper was filled with particles then oscillated vertically at high frequency (~10 kHz), amplitude and frequency were scaled from the experimental system. Two orifice sizes, a variety of DEM parameters and two vibration modes were simulated. The parametric study of DEM parameters was based around a case that provided flow rates within a factor of 2 of the experimental flow rates. Dispensing after vibration was found to stop very quickly as in experiments. Visualisation of internal structures during fill, vibration and immediately after vibration revealed a central mass of slow moving particles floating above the nozzle outlet. When the vibration stops the central mass of particles drops into contact with the walls and quickly plugs the flow
Spinal performance and functional impairment in postmenopausal women with osteoporosis and osteopenia without vertebral fracture
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