On the use of ray tracing programmable frameworks for radio wave propagation prediction

International Conference on Wireless Networks and Mobile Communication (EUIWNMC), 26/08/2021-27/08/2021, Marrakesh, Marruecos.This work focuses on the use of ray tracing programmable frameworks, like Nvidia Optix, for radio wave propagation prediction. Although these frameworks are oriented to graphics visualization, they can be tailored to calculate specular reflections on walls and diffractions in edges of buildings. Once all the paths between the transmitter and the receiver are obtained, Maxwell"s equations can be applied to compute the path loss or the received power.Comunidad de Madri

Tools for ray tracing based radio channel modeling and simulation

Abstract. Ray tracing-based methods have become the state of the art for radio channel propagation modeling simulations. They provide a way to deterministically simulate field strength and multidispersive characteristics of the radio channel, and thus, offer a faster and easier alternative to measuring. Ray tracing is also an important tool for validating algorithms, and many applications can utilize the simulation results. As the wireless networks suffer from increasing complexity, the interest in machine learning and artificial intelligence solutions is increasing as well, and in this context the simulation results can be utilized as training data. We introduce the relevant theory in radio propagation modeling in the context of ray tracing, followed by theory of graphics processing unit-based computing, architecture, and ray tracing. We present multiple existing graphics processing unit and ray tracing-based radio channel propagation modeling implementations from the literature. We then develop multiple optimized versions of an existing environment discretization-based path search implementation and develop a path refiner for refining the coarse paths generated by the path search. The path refiner computes the optimal paths, and then validates them by utilizing ray tracing. Experiments for the developed solutions are conducted with an indoor and an outdoor model on two different computer setups. We achieve on average over 25 times faster computation in the outdoor scene and over 4 times faster computation in the indoor scene when compared to the original path search implementation. The path refiner is able to find the optimal paths fulfilling the Fermat’s principle of least time on average for over 96% of the coarse paths in the outdoor scene, and for over 99% in the indoor scene. From these refined paths, on average about 62% pass the validation phase in the outdoor case, and around 30% in the indoor case. The results show that the path refinement combined with validation is essential for improving the quality of the paths found by the initial discretization-based search.Työkaluja säteenseurantaan perustuvaan radiokanavamallinnukseen ja simulointiin. Tiivistelmä. Säteenseurantaan perustuvat menetelmät ovat edistyneintä tekniikkaa radiokanavien etenemisen mallinnussimulaatioissa. Ne tarjoavat tavan deterministisesti arvioida radiokanavan kentänvoimakkuutta ja monidispersiivisiä ominaisuuksia ja siten tarjoavat nopeamman ja helpomman vaihtoehdon mittaamiselle. Säteenseuranta on myös tärkeä työkalu algoritmien validoinnissa ja useissa sovelluksissa voidaan hyödyntää simulointien tuloksia. Langattomien verkkojen monimutkaisuuden lisääntyessä myös kiinnostus koneoppimis- ja tekoälypohjaisiin ratkaisuihin lisääntyy, ja tässä yhteydessä simulointien tuloksia voidaan hyödyntää opetusdatana. Tässä työssä esitellään teoriaa radiokanavan etenemisen mallinnuksesta säteenseurantaan perustuen, jonka jälkeen esitellään näytönohjainpohjaisen laskennan, arkkitehtuurin, sekä säteenseurannan teoriaa. Tämän jälkeen tarkastellaan useita olemassa olevia näytönohjain- ja säteenseurantapohjaisia radiokanavan etenemistä mallintavia toteutuksia. Työssä kehitetään useita optimoituja versioita olemassa olevasta ympäristön diskretisointiin perustuvasta polunetsintätoteutuksesta ja kehitetään poluntarkentaja tarkentamaan sen tuottamia epäoptimaalisia polkuja. Poluntarkentaja laskee optimaaliset polut ja validoi ne hyödyntämällä säteenseurantaa. Ratkaisuiden tehokkuutta arvioidaan sekä ulko- että sisätilan malleille tehtävillä laskennoilla kahdella eri tietokoneella. Paras polunetsintäversio saavuttaa keskimäärin yli 25 kertaa nopeamman laskennan ulkotilassa ja yli 4 kertaa nopeamman laskennan sisätilassa verrattaessa alkuperäiseen toteutukseen. Poluntarkentaja löytää optimaaliset polut, jotka täydentävät Fermat’n periaatteen lyhyimmästä ajasta keskimäärin yli 96 prosentille karkeista poluista ulkotilassa ja yli 99 prosentille sisätilassa. Näistä tarkennetuista poluista keskimäärin noin 62 prosenttia pääsee läpi validoinnista ulkotilassa ja noin 30 prosenttia sisätilassa. Tulokset osoittavat, että polkujen tarkennus ja validointi ovat tärkeitä alkuperäisen diskretisointipohjaisen haun löytämien polkujen laadun parantamiseksi

Molecular phylogeny of horseshoe crab using mitochondrial Cox1 gene as a benchmark sequence

An effort to assess the utility of 650 bp Cytochrome C oxidase subunit I (DNA barcode) gene in delineating the members horseshoe crabs (Family: xiphosura) with closely related sister taxa was made. A total of 33 sequences were extracted from National Center for Biotechnological Information (NCBI) which include horseshoe crabs, beetles, common crabs and scorpion sequences. Constructed phylogram showed beetles are closely related with horseshoe crabs than common crabs. Scorpion spp were distantly related to xiphosurans. Phylogram and observed genetic distance (GD) date were also revealed that Limulus polyphemus was closely related with Tachypleus tridentatus than with T.gigas. Carcinoscorpius rotundicauda was distantly related with L.polyphemus. The observed mean Genetic Distance (GD) value was higher in 3rd codon position in all the selected group of organisms. Among the horseshoe crabs high GC content was observed in L.polyphemus (38.32%) and lowest was observed in T.tridentatus (32.35%). We conclude that COI sequencing (barcoding) could be used in identifying and delineating evolutionary relatedness with closely related specie

Crab and cockle shells as heterogeneous catalysts in the production of biodiesel

In the present study, the waste crab and cockle shells were utilized as source of calcium oxide to transesterify palm olein into methyl esters (biodiesel). Characterization results revealed that the main component of the shells are calcium carbonate which transformed into calcium oxide upon activated above 700 °C for 2 h. Parametric studies have been investigated and optimal conditions were found to be catalyst amount, 5 wt.% and methanol/oil mass ratio, 0.5:1. The waste catalysts perform equally well as laboratory CaO, thus creating another low-cost catalyst source for producing biodiesel. Reusability results confirmed that the prepared catalyst is able to be reemployed up to five times. Statistical analysis has been performed using a Central Composite Design to evaluate the contribution and performance of the parameters on biodiesel purity

Safety and Reliability - Safe Societies in a Changing World

The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen