Vehicle Talks to IoT for Better Driving Experience

Internet of vehicles (IoV), or vehicles to everything (V2X), is a relatively new concept for all vehicles connected to the internet. In this paper, we propose a solution to the problems of traffic congestion. Road traffic congestion has continued to be a major problem in many developed countries. This concept shows the place or location traffic congestion occurs at the time of rainfall, the position of the data based on GPS, and the sensors in the vehicle. The sensors in vehicles are used to collect information for the purpose of evaluating traffic congestion through cloud server via protocols such as CoAP and MQTT. At the beginning of the study, the authors introduced the problems and then proposed a solution

Development of Microwave Non-destructive Inspection Equipment for Outer Wall Tiles

The separation of tiles from buildings degrades the aesthetic appeal of buildings and may result in structural failure. Therefore, tiles should be inspected periodically. However, manual inspections are expensive and require qualified experts. In this study, voids corresponding to tile separation were detected in a concrete specimen using non-destructive inspection based on electromagnetic wave detection. Furthermore, wave reflection models of healthy and defective tiles were created, and the effects of the void plane size on the reflection of defective tiles were considered. The correlation between the void plane size and the reflection intensity difference integral value was verified through multi-layer scanning using these models. The multi-layer scanning method (MLS) provides a qualitative and fundamental solution to this dilemma. Because it is based on multiple scans, it still has the potential to improve the quantity and location of the required scanning layers, increasing the accuracy and speed of the results. MLS was conducted on actual tiled concrete, including several sizes of voids. Comparing the simulation and experimental results showed a possibility of optimizing the number of scan layers. The ability to optimize scanning layers was demonstrated both theoretically and empirically. The aim of discovering the voids under the tiles is to avoid the tiles falling from the building, but the one responsible for the tiles falling is the strength of the adhesion. Therefore, this study presents a method in which the strength of adhesion of tiles can be predicted through the intensity of wave reflection from defective tiles

Modeling 3D Laplace-Fourier domain acoustic wave equation with free-surface topography using finite-difference

We develop embedded boundary methods to handle arbitrarily shaped topography to ac- curately simulate acoustic seismic wave propagation in Laplace-Fourier (LF) domain. The purpose is to use this method to enhance accurate wave simulation near the surface. Unlike most existing methods such as the ones using curvilinear grids to fit irregular surface topography, we use regular Cartesian grid system without suffering from staircasing error, which occurs in the conventional implementations. In this improved embedded-boundary method, we account for an arbitrarily curved surface by imposing ghost nodes above the surface and approximating their acoustic pressures using linear extrapolation, quadratic interpolation, or cubic interpolation. Implementing this method instead of using curvilinear grids near the boundaries greatly reduces the complexity of preprocessing procedures and the computational cost. Furthermore, using numerical examples, we show the accuracy gain and performance of our embedded-boundary methods in comparison with conventional finite-difference (FD) implementation of the problem.In realistic 3D geological settings underlying topography surfaces with a large velocity contrast between shallow and deep regions, simulation of acoustic wave propagation in LF domain using a spatially uniform grid can be computationally demanding, due to over-discretization of the high-velocity material. We introduce a discontinuous mesh (DM) method that exchanges information between regions, discretized with different grid spacings, to improve efficiency and convergence. We present a 3D second- and fourth-order velocity- pressure staggered-grid FD DM acoustic wave propagation method in LF domain for acoustic wave estimation using any spatial discretization ratio between meshes. We evaluate direct and iterative parallel solvers for computational speed, memory requirements and convergence. Benchmarks in realistic 3D models with extreme and realistic topography examples show more efficient and stable results for DM with direct solvers relative to uniform mesh with iterative solvers

Modeling 3D Laplace-Fourier domain acoustic wave equation with free-surface topography using finite-difference

We develop embedded boundary methods to handle arbitrarily shaped topography to ac- curately simulate acoustic seismic wave propagation in Laplace-Fourier (LF) domain. The purpose is to use this method to enhance accurate wave simulation near the surface. Unlike most existing methods such as the ones using curvilinear grids to fit irregular surface topography, we use regular Cartesian grid system without suffering from staircasing error, which occurs in the conventional implementations. In this improved embedded-boundary method, we account for an arbitrarily curved surface by imposing ghost nodes above the surface and approximating their acoustic pressures using linear extrapolation, quadratic interpolation, or cubic interpolation. Implementing this method instead of using curvilinear grids near the boundaries greatly reduces the complexity of preprocessing procedures and the computational cost. Furthermore, using numerical examples, we show the accuracy gain and performance of our embedded-boundary methods in comparison with conventional finite-difference (FD) implementation of the problem.In realistic 3D geological settings underlying topography surfaces with a large velocity contrast between shallow and deep regions, simulation of acoustic wave propagation in LF domain using a spatially uniform grid can be computationally demanding, due to over-discretization of the high-velocity material. We introduce a discontinuous mesh (DM) method that exchanges information between regions, discretized with different grid spacings, to improve efficiency and convergence. We present a 3D second- and fourth-order velocity- pressure staggered-grid FD DM acoustic wave propagation method in LF domain for acoustic wave estimation using any spatial discretization ratio between meshes. We evaluate direct and iterative parallel solvers for computational speed, memory requirements and convergence. Benchmarks in realistic 3D models with extreme and realistic topography examples show more efficient and stable results for DM with direct solvers relative to uniform mesh with iterative solvers

Colorectal cancer in patients with SARS-CoV-2: a systematic review and meta-analysis

Background: Patients with colorectal cancer (CRC) are more likely to develop severe course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and experience increased risk of mortality compared to SARS-CoV-2 patients without CRC. Objectives: To estimate the prevalence of SARS-CoV-2 infection in CRC patients and analyse the demographic parameters, clinical characteristics and treatment outcomes in CRC patients with COVID-19 illness. Methods: For this systematic review and meta-analysis, we searched Proquest, Medline, Embase, Pubmed, CINAHL, Wiley online library, Scopus and Nature for studies on the incidence of SARS-CoV-2 infection in CRC patients, published from December 1, 2019 to December 31, 2021, with English language restriction. Effect sizes of prevalence were pooled with 95% confidence intervals (CIs). Sub-group analyses were performed to minimize heterogeneity. Binary logistic regression model was used to explore the effect of various demographic and clinical characteristics on patient's final treatment outcome (survival or death). Results: Of the 472 papers that were identified, 69 articles were included in the systematic review and meta-analysis (41 cohort, 16 case-report, 9 case-series, 2 cross-sectional, and 1 case-control studies). Studies involving 3362 CRC patients with confirmed SARS-CoV-2 (all patients were adults) were analyzed. The overall pooled proportions of CRC patients who had laboratory-confirmed community-acquired and hospital-acquired SARS-CoV-2 infections were 8.1% (95% CI 6.1 to 10.1, n = 1308, 24 studies, I2 98%, p = 0.66), and 1.5% (95% CI 1.1 to 1.9, n = 472, 27 studies, I2 94%, p < 0.01). The median patient age ranged from 51.6 years to 80 years across studies. The majority of the patients were male (n = 2243, 66.7%) and belonged to White (Caucasian) (n = 262, 7.8%), Hispanic (n = 156, 4.6%) and Asian (n = 153, 4.4%) ethnicity. The main source of SARS-CoV-2 infection in CRC patients was community-acquired (n = 2882, 85.7%; p = 0.014). Most of those SARS-CoV-2 patients had stage III CRC (n = 725, 21.6%; p = 0.036) and were treated mainly with surgical resections (n = 304, 9%) and chemotherapies (n = 187, 5.6%), p = 0.008. The odd ratios of death were significantly high in patients with old age (≥ 60 years) (OR 1.96, 95% CI 0.94-0.96; p < 0.001), male gender (OR 1.44, 95% CI 0.41-0.47; p < 0.001) CRC stage III (OR 1.54, 95% CI 0.02-1.05; p = 0.041), CRC stage IV (OR 1.69, 95% CI 0.17-1.2; p = 0.009), recent active treatment with chemotherapies (OR 1.35, 95% CI 0.5-0.66; p = 0.023) or surgical resections (OR 1.4, 95% CI 0.8-0.73; p = 0.016) and admission to ICU (OR 1.88, 95% CI 0.85-1.12; p < 0.001) compared to those who survived. Conclusion: SARS-CoV-2 infection in CRC patient is not uncommon and results in a mortality rate of 26.2%. Key determinants that lead to increased mortality in CRC patients infected with COVID-19 include older age (≥ 60 years old); male gender; Asian and Hispanic ethnicity; if SARS-CoV-2 was acquired from hospital source; advanced CRC (stage III and IV); if patient received chemotherapies or surgical treatment; and if patient was admitted to ICU, ventilated or experienced ARDS