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The complexity and abstraction of the electromagnetic environment make the visual perception of the battlefield electromagnetic situation very difficult, which also highlights the importance of developing an integrated electromagnetic situation simulation system which integrates the electromagnetic environment visualization, the equipment interference analysis and the military action deduction. To...
The most widely used method in recommendation systems is collaborative filtering, of which, a critical step is to analyze a user's preferences and make recommendations of products or services based on similarity analysis with other users' ratings. However, collaborative filtering is less usable for recommendation facing the “cold start” problem, i.e. few comments being given to products or services...
The performance of the systems which based on wireless signals such as localization system relies mostly on the propagation model. Radio signals can be mainly difficult to model because the channel varies significantly with the environment such as indoors. This paper studies two popular propagation models for indoor environments. Practically, these models do not estimate the radio signal fading properly...
In this paper, an empirical propagation model for indoor corridor at 5 GHz based on ray tracing dataset has been proposed. The model can predict the line-of-sight (LOS) and non-line-of-sight (NLOS) path loss characteristics for indoor corridor with T-junction using distances from the junction to the transmitter and receiver, while taking into account the width of the corridor.
For point-to-point backhaul systems located in a vegetated residential area, the base-station transmitter is located close to the surrounding rooftops; the propagation takes place over the rooftops and through the canopy of the trees. The receivers, in many cases, are also located close to the surrounding rooftops or well below them. The objective of the present paper is to use the Torrico-Bertoni-Lang...
Ocean analyses, forecasts and ensembles characterizing oceanographic uncertainty are becoming widely available. Acousticians are interested in the impacts of oceanographic variability (temporal and spatial) and uncertainty on acoustic propagation, however, it is very time consuming to compute acoustic propagation along many potential paths for multiple sensors, over a geographic area for many analysis...
Acoustic transmission loss (TL) has been computed using oceanography modeled by the Navy Coastal Ocean Model (NCOM) over an 18 month time period in the Western Pacific Ocean [Jacobs, G. A., J. G. Richman, J. D. Doyle, P. L. Spence, B. P. Bartels, C. N. Barron, R. W. Helber, and F. L. Bub (2014), Simulating conditional deterministic predictability within ocean frontogenesis, Ocean Modelling, 78, 1–16]...
This paper presents a time domain model of the non-contact surface wave (SW) ultrasonic scanner. Computations are divided into three steps: wave propagation from air-coupled emitter to the inspected sample (step 1), SW propagation along the inspected sample surface (step 2), leaky wave re-propagation from sample to air-coupled receiver (step 3). Each step is computed based on Rayleigh's integral employing...
Electronic word-of-mouth (eWOM) is an important information source that influences consumer product evaluations. The author previously developed a computational model, called an inference space model, that predicts potency-magnitude relations between eWOM messages by comparing their numerical values, called inference quantum values. This paper focuses on superlative type messages and formalizes a...
Due to the wide deployment of indoor wireless local area networks (WLANs), the indoor planning became a research of interest for IT as well as networking researchers. As a result of this wide deployment, many IT applications and services started relying on the ready implemented WLAN infrastructure. Therefore, there is a need for reliable propagation models which are able to predict the WLAN signal...
In this study, propagation prediction models based on ray tracing in coverage estimation for broadcasting systems are compared with respect to computation time and accuracy in the case of close building heights. Uniform Theory of Diffraction (UTD), Slope Diffraction (S-UTD) and Slope UTD with Convex Hull (S-UTD-CH) models are compared for computation time and propagation path loss. Moreover in this...
We discuss the applicability of simplified Two-Ray Ground path loss models to simulation-based performance evaluation studies of Inter-Vehicle Communication (IVC) protocols. We contrast this with the applicability of a more exact Two-Ray Interference model. A key result is that, in most cases, the commonly used simplified Two-Ray Ground models add no additional value compared to the most simple Free-space...
A general path loss model for in-room radio channels is proposed. The model is based on experimental observations of the behavior of the delay-power spectrum in closed rooms. In such a room, the early part of the spectrum observed at different positions typically consists of a dominant component (peak) that vanishes as the transmitter-receiver distance increases; the late part decays versus distance...
In simulation environments, prediction of path losses, maximum communication coverage for each node and received signal strength are calculated by using propagation model. However, most of the simulation tools only offer simple propagation model that neglected obstacles in the propagation environment. This paper reviews a variety of more realistic propagation models for Wireless Sensor Networks and...
In this paper we propose a new Direction-specific Land use based Path loss model (DiLaP) that benefits from both approaches by utilizing the particular radio wave propagation characteristics of all land use segments that lay on the direct path between receiver and transmitter. It is intended for application to suburban/rural areas.
Random Search is one of the most well-known model for area search. However, because of its simplicity, it has inherent limitations. For example, it assumes that the searcher and target search areas are identical and that the searcher uses a perfect cookie-cutter sensor. In this study, we develop a MATLAB simulation of area search with acoustic sensors modeled by the Poisson Scan model and the Lambda-Sigma...
Due to the heterogeneity and the multigrain parallelism of the heterogeneous multi-core computer, communication and memory access show hierarchical characteristics ignored by other models. In this paper, a new model named mPlogP, is presented on the basis of the PlogP model, in which communication and memory access is abstracted by considering these new characteristics of the heterogeneous multi-core...
A prediction model of GPS multipath requires a constant trade-off between computation time and realistic modeling. In previous papers we have presented a GPS multipath simulator based on physical optics. Regarding the design of this deterministic model, we have carefully justified the choices we have made to obtain reasonable computation times. They concern both the electromagnetic method and the...
Indoor propagation models attract much interest these days because of their importance in the applications of 3G/4G network planning and optimisation. The accuracy and running speed directly affects the practical use of such models. This paper extends a discrete ray launching model IRLA (Intelligent Ray Launching Algorithm) to indoor scenarios. A typical office room will be selected to validate this...
This work presents a new radio paths computation frame-work especially designed for complex indoor RF field prediction. We propose a new algorithm utilizing a geometric visibility graph of a building to traverse all possible bounded radio paths. These paths are needed to compute the signal strength as received at given receiver location. We have implemented the suggested algorithm and performed a...
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