Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure Channels

We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore identify the most dominant stopping sets for the distributions of practical interest. The derived analytical expressions allow us to accurately predict the error floor at low to moderate channel loads and characterize the unequal error protection inherent in CSA

Broadcast Coded Slotted ALOHA: A Finite Frame Length Analysis

We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a half-duplex mode. The half-duplex mode gives rise to a double unequal error protection (DUEP) phenomenon: the more a user repeats its packet, the higher the probability that this packet is decoded by other users, but the lower the probability for this user to decode packets from others. We analyze the performance of B-CSA over the packet erasure channel for a finite frame length. In particular, we provide a general analysis of stopping sets for B-CSA and derive an analytical approximation of the performance in the error floor (EF) region, which captures the DUEP feature of B-CSA. Simulation results reveal that the proposed approximation predicts very well the performance of B-CSA in the EF region. Finally, we consider the application of B-CSA to vehicular communications and compare its performance with that of carrier sense multiple access (CSMA), the current MAC protocol in vehicular networks. The results show that B-CSA is able to support a much larger number of users than CSMA with the same reliability.Comment: arXiv admin note: text overlap with arXiv:1501.0338

All-to-all Broadcast for Vehicular Networks Based on Coded Slotted ALOHA

We propose an uncoordinated all-to-all broadcast protocol for periodic messages in vehicular networks based on coded slotted ALOHA (CSA). Unlike classical CSA, each user acts as both transmitter and receiver in a half-duplex mode. As in CSA, each user transmits its packet several times. The half-duplex mode gives rise to an interesting design trade-off: the more the user repeats its packet, the higher the probability that this packet is decoded by other users, but the lower the probability for this user to decode packets from others. We compare the proposed protocol with carrier sense multiple access with collision avoidance, currently adopted as a multiple access protocol for vehicular networks. The results show that the proposed protocol greatly increases the number of users in the network that reliably communicate with each other. We also provide analytical tools to predict the performance of the proposed protocol.Comment: v2: small typos fixe

Probabilistic Handshake in All-to-all Broadcast Coded Slotted ALOHA

We propose a probabilistic handshake mechanism for all-to-all broadcast coded slotted ALOHA. We consider a fully connected network where each user acts as both transmitter and receiver in a half-duplex mode. Users attempt to exchange messages with each other and to establish one-to-one handshakes, in the sense that each user decides whether its packet was successfully received by the other users: After performing decoding, each user estimates in which slots the resolved users transmitted their packets and, based on that, decides if these users successfully received its packet. The simulation results show that the proposed handshake algorithm allows the users to reliably perform the handshake. The paper also provides some analytical bounds on the performance of the proposed algorithm which are in good agreement with the simulation results

Eddy current testing probe optimization using a parallel genetic algorithm

This paper uses the developed parallel version of Michalewicz's Genocop III Genetic Algorithm (GA) searching technique to optimize the coil geometry of an eddy current non-destructive testing probe (ECTP). The electromagnetic field is computed using FEMM 2D finite element code. The aim of this optimization was to determine coil dimensions and positions that improve ECTP sensitivity to physical properties of the tested devices

Detecting Check-Worthy Claims in Political Debates, Speeches, and Interviews Using Audio Data

A large portion of society united around the same vision and ideas carries enormous energy. That is precisely what political figures would like to accumulate for their cause. With this goal in mind, they can sometimes resort to distorting or hiding the truth, unintentionally or on purpose, which opens the door for misinformation and disinformation. Tools for automatic detection of check-worthy claims would be of great help to moderators of debates, journalists, and fact-checking organizations. While previous work on detecting check-worthy claims has focused on text, here we explore the utility of the audio signal as an additional information source. We create a new multimodal dataset (text and audio in English) containing 48 hours of speech. Our evaluation results show that the audio modality together with text yields improvements over text alone in the case of multiple speakers. Moreover, an audio-only model could outperform a text-only one for a single speaker.Comment: check-worthy claims, fake news, political debates, audi

SU(3)-instantons and G2,Spin(7)G_2, Spin(7)-heterotic string solitons

Necessary and sufficient conditions to the existence of a hermitian connection with totally skew-symmetric torsion and holonomy contained in SU(3) are given. Non-compact solution to the supergravity-type I equations of motion with non-zero flux and non-constant dilaton is found in dimensions 6. Non-conformally flat non-compact solutions to the supergravity-type I equations of motion with non-zero flux and non-constant dilaton are found in dimensions 7 and 8. A Riemannian metric with holonomy contained in $G_2$ arises from our considerations and Hitchin's flow equations, which seems to be new. Compact examples of $SU(3), G_2$ and $Spin(7)$ instanton satisfying the anomaly cancellation conditions are presented.Comment: LaTex, 22 pages, Corrected anomaly cancellation, final version to appear in Commun. Math. Phy

Phytosanitary Status of Wheat Crops in Northeastern Bulgaria

In the present work, the results of a survey of wheat crops in the area of the IASS quot%253BObraztsov chiflikquot%253B ndash%253B Ruse are presented. The study was carried out during the period 2018-2021, at the experimental field of the institute, according to accepted methods for weed infestation, species composition of the entomofauna and economically important wheat diseases. The aim of the study is to determine the species composition of weeds, diseases and insect pest in wheat crops under the relevant agro-climatic conditions. Weed species composition differed by year, with a total of 15 weed species from 10 families recorded. Veronica agrestis L., Lamium purpureum L., Anthemis arvensis L., Convolvulus arvensis L. and Cirsium arvense L. are ubiquitous in surveyed crop. Insects belonging to the orders Coleoptera, Diptera, Hemiptera, Homoptera, Hymenoptera, Lepidoptera, Neuroptera and Orthoptera were identified. The proportion of the orders to which the species belonged in the three years of the study differed in culture. The total number of insects detected during the three years of the test varied on average (CV%253D15.63%25) ndash%253B 373 pcs. in 2019, 280 pcs. in 2020 and 372 pcs. in 2021. During the period, 3 fungal pathogens of the genera Puccinia, Erysiphe and Septoria were identified. The development of Puccinia and Erysiphe pathogens during the study period was within acceptable limits according to the SEV scale (from 10%25 to 25%25). Massive development of the pathogen Septoria sp. was observed, with the affected plant area reaching up to 65%25, according to the SEV scale

How different strains of COVID-19 affect LUTS in BPH patients?

In late 2019, an outbreak of pneumonia of unknown etiology was reported in Wuhan (China). The causative agent was quickly identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the impact of COVID-19 (coronavirus disease 2019) on various organs and symptoms has been studied, there is still a dearth of data regarding its effect on the genitourinary system. In this study, we investigated the impact of different COVID-19 strains on lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH). A total of 69 patients who had previously been infected with COVID-19 from August 2021 to October 2021 and January 2022 to May 2022 were assessed. The two periods were purposively selected based on the dominant COVID-19 variant: the Delta strain for the first period and Omicron for the second, respectively. All patients had BPH and were followed up in two outpatient practices. Demographic information was collected, and LUTS were assessed using the international prostate symptom score (IPSS) questionnaires before and after COVID-19. Ultrasound examinations were performed to determine the prostate gland volume and the post-voided residual (PVR) in each patient. All patients affected by COVID-19 exhibited a worsening of LUTS. The degree of deterioration differed between those infected with different COVID-19 strains. Patients infected with the Delta strain had more severe LUTS than those with the Omicron strain. There is currently limited information available regarding the emerging pathophysiological processes in the urogenital system related to COVID-19. This present study serves as a preliminary investigation into the impact of COVID-19 on LUTS in BPH patients and could serve as a basis for more extensive multicenter studies leading to fundamental discoveries

Prunus spinosa L. leaf extracts: polyphenol profile and bioactivities

Prunus spinosa leaf extracts in solvents of different polarity (water, ethanol and acetone), their phenol, flavonoid and anthocyanin contents and biological properties were the object of this study. The richest in phenols as well as in flavonoids was acetone extract with 181.19 mg GAE and 80.10 mg QE per gram of dry extract, respectively. Moreover, the quantity of anthocyanins obtained by HPLC analysis was also the highest in acetone sample. Examined samples possessed antioxidant properties evaluated through four in vitro assays (DPPH, ABTS, FRAP and TRC). The acetone extract was proved to be the best antioxidant among tested samples, which could be ascribed to polyphenols, especially anthocyanins. The aqueous and the ethanol extract exhibited antibacterial effects, being particularly active against B. cereus and E. cloacae. T. viride, P. funiculosum, P. ochrochloron, P. verrucosum var. cyclopium were the most susceptible among fungal microorganisms examined. Both, the aqueous and the ethanol extract expressed inhibitory activity towards enzymes linked to diabetes mellitus type II. Additionally, the ethanol extract showed significantly higher potential in inhibiting α-glucosidase than the drug used as the positive control. Furthermore, the aqueous sample revealed antitumor effects on following malignant cell lines: HeLa, K562 and MDA-MB-453. The results presented herein suggest that P. spinosa leaves should be considered as a natural source of bioactive compounds with potential application in phytopharmacy and food industry