A high-speed 2.5D ray-tracing propagation model for microcellular systems, application: Smart cities

2017 ◽  
Author(s):  
Taha Alwajeeh ◽  
Pierre Combeau ◽  
Rodolphe Vauzelle ◽  
Ahcene Bounceur
Keyword(s):  
Ray Tracing ◽  
High Speed ◽  
Smart Cities ◽  
Propagation Model

scholarly journals Implementation analysis of IoT-based offloading frameworks on cloud/edge computing for sensor generated big data

2021 ◽  
Author(s):  
Karan Bajaj ◽  
Bhisham Sharma ◽  
Raman Singh
Keyword(s):  
High Speed ◽  
Smart Cities ◽  
Fog Computing ◽  
Edge Computing ◽  
Computation Offloading ◽  
Performance Parameters ◽  
Iot Applications ◽  
Time Sensitivity ◽  
Implementation Analysis ◽  
Increasing Demand

AbstractThe Internet of Things (IoT) applications and services are increasingly becoming a part of daily life; from smart homes to smart cities, industry, agriculture, it is penetrating practically in every domain. Data collected over the IoT applications, mostly through the sensors connected over the devices, and with the increasing demand, it is not possible to process all the data on the devices itself. The data collected by the device sensors are in vast amount and require high-speed computation and processing, which demand advanced resources. Various applications and services that are crucial require meeting multiple performance parameters like time-sensitivity and energy efficiency, computation offloading framework comes into play to meet these performance parameters and extreme computation requirements. Computation or data offloading tasks to nearby devices or the fog or cloud structure can aid in achieving the resource requirements of IoT applications. In this paper, the role of context or situation to perform the offloading is studied and drawn to a conclusion, that to meet the performance requirements of IoT enabled services, context-based offloading can play a crucial role. Some of the existing frameworks EMCO, MobiCOP-IoT, Autonomic Management Framework, CSOS, Fog Computing Framework, based on their novelty and optimum performance are taken for implementation analysis and compared with the MAUI, AnyRun Computing (ARC), AutoScaler, Edge computing and Context-Sensitive Model for Offloading System (CoSMOS) frameworks. Based on the study of drawn results and limitations of the existing frameworks, future directions under offloading scenarios are discussed.

scholarly journals Multistage Asymmetric Rotors Coaxial Measurement Stacking Method Based on Minimization of Exciting Force

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1054
Author(s):  
Yongmeng Liu ◽  
Yingjie Mei ◽  
Chuanzhi Sun ◽  
Pinghuan Xiao ◽  
Ruirui Li ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
High Speed ◽  
Geometric Error ◽  
Exciting Force ◽  
Propagation Model ◽  
Assembly Method ◽  
Geometric Center ◽  
Asymmetric Rotor ◽  
Rotor Equipment ◽  
Geometric Error Measurement

The unbalanced exciting force of high-speed rotary asymmetric rotor equipment is the main factor causing rotor vibration. In order to effectively suppress the vibration of the asymmetric rotor equipment, the paper establishes a multistage asymmetric rotor coaxial measurement stacking method that minimizes the exciting force. By analyzing the propagation process of the centroid of the multistage asymmetric rotor assembly and analyzing the relationship between the geometric center and the centroid of a single asymmetric rotor, a multistage asymmetric unbalanced rotor propagation model based on geometric center stacking is established. The genetic algorithm is used to optimize the unbalance of the multistage asymmetric rotors. Combined with the vibration principle under the exciting force, the vibration amplitude of the left bearing at different rotation speeds under the minimization of the exciting force and the random assembly phase is analyzed. Finally, the experimental asymmetric rotors are dynamically measured, combined with the asymmetric rotors’ geometric error measurement experiment. The experimental results confirm that the vibration amplitude of the assembly phase with the minimum exciting force is smaller than the vibration amplitude under the random assembly phase at three-speed modes, and the optimization rate reached 73.2% at 9000 rpm, which proves the effectiveness of the assembly method in minimizing the exciting force.

scholarly journals Broadband Wireless Channel in Composite High-Speed Railway Scenario: Measurements, Simulation, and Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Jianwen Ding ◽  
Lei Zhang ◽  
Jingya Yang ◽  
Bin Sun ◽  
Jiying Huang
Keyword(s):  
Ray Tracing ◽  
Communication Systems ◽  
High Speed ◽  
Channel Model ◽  
High Reliability ◽  
Rapid Development ◽  
Path Loss ◽  
Wireless Channel ◽  
Delay Spread ◽  
High Speed Railway

The rapid development of high-speed railway (HSR) and train-ground communications with high reliability, safety, and capacity promotes the evolution of railway dedicated mobile communication systems from Global System for Mobile Communications-Railway (GSM-R) to Long Term Evolution-Railway (LTE-R). The main challenges for LTE-R network planning are the rapidly time-varying channel and high mobility, because HSR lines consist of a variety of complex terrains, especially the composite scenarios where tunnels, cuttings, and viaducts are connected together within a short distance. Existing researches mainly focus on the path loss and delay spread for the individual HSR scenarios. In this paper, the broadband measurements are performed using a channel sounder at 950 MHz and 2150 MHz in a typical HSR composite scenario. Based on the measurements, the pivotal characteristics are analyzed for path loss exponent, power delay profile, and tap delay line model. Then, the deterministic channel model in which the 3D ray-tracing algorithm is applied in the composite scenario is presented and validated by the measurement data. Based on the ray-tracing simulations, statistical analysis of channel characteristics in delay and Doppler domain is carried out for the HSR composite scenario. The research results can be useful for radio interface design and optimization of LTE-R system.

scholarly journals Intelligent Ray-Tracing: an efficient indoor ray propagation model

2011 ◽  
Vol 8 (22) ◽  
pp. 1920-1926 ◽  
Author(s):  
Ahmed Wasif Reza ◽  
Kaharudin Dimyati ◽  
Kamarul Ariffin Noordin ◽  
Md. Sumon Sarker
Keyword(s):  
Ray Tracing ◽  
Propagation Model

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

An improved ray-tracing propagation model for predicting path loss on single floors

1999 ◽  
Vol 22 (1) ◽  
pp. 39-41 ◽  
Author(s):  
Zhong Ji ◽  
Bin-Hong Li ◽  
Hao-Xing Wang ◽  
Hsing-Yi Chen ◽  
Yaw-Gen Zhau
Keyword(s):  
Ray Tracing ◽  
Path Loss ◽  
Propagation Model

Correct ray-tracing analysis for interference microscopy of fibres

1995 ◽  
Vol 450 (1938) ◽  
pp. 23-36 ◽  
Keyword(s):  
Refractive Index ◽  
Ray Tracing ◽  
High Speed ◽  
Nonlinear Least Squares ◽  
Fibre Surface ◽  
Refractive Index Profile ◽  
Initial Result ◽  
Interference Microscopy ◽  
Radial Density ◽  
Round Cross Section

A ray-tracing analysis for calculating, by means of interference microscope data, the radial distribution of refractive index, n ( r ), for fibres of round cross section has been formulated, solved, tested and used to determine n ( r ) for high-speed direct-spun polyethylene terephthalate (PET) fibres. The formulation was based on work by Kahl & Mylin (1965) originally performed to explore the radial density profiles in cylindrically symmetrical explosions. The equations were formulated with proper boundary conditions at the fibre surface, correcting a fundamental error that has caused problems for 20 years. This correct boundary condition unfortunately made it impossible to invert, as had been done in all previous work, the resulting integral equations, which consequently were solved by a nonlinear least-squares approximation. The analysis corrected a serious problem noted in the literature: namely, that the refractive index profile obtained for a particular fibre depended on the refractive index of the immersion liquid used to make the measurement. Refractive index profiles observed for PET fibres produced by high-speed direct spinning had concave-down curvature, the opposite of expectations based on previous work. This initial result suggests that when direct-spun, under crystallizing conditions, PET fibres develop a mainly radial density or quench profile, whereas fibres spun under conditions that give little crystallinity have a mainly radial orientation gradient. Experiments to test this suggestion further have not been done yet.

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