Path loss model for outdoor parking environments at 28 GHz and 38 GHz for 5G wireless networks

It has been widely speculated that the performance of the next generation Internet of Things (IoT) based wireless network should meet a transmission speed on the order of 1000 times more than current wireless networks; energy consumption on the order of 10 times less and access delay of less than 1 ns that will be provided by future 5G systems. To increase the current mobile broadband capacity in future 5G systems, the millimeter wave (mmWave) band will be used with huge amounts of bandwidth available in this band. Hence, to support this wider bandwith at the mmWave band, new radio access technology (RAT) should be provided for 5G systems. The new RAT with symmetry design for downlink and uplink should support different scenarios such as device to device (D2D) and multi-hop communications. This paper presents the path loss models in parking lot environment which represents the multi-end users for future 5G applications. To completely assess the typical performance of 5G wireless network systems across these different frequency bands, it is necessary to develop path loss (PL) models across these wide frequency ranges. The short wavelength of the highest frequency bands provides many scatterings from different objects. Cars and other objects are some examples of scatterings, which represent a critical issue at millimeter-wave bands. This paper presents the large-scale propagation characteristics for millimeter-wave in a parking lot environment. A new physical-based path loss model for parking lots is proposed. The path loss was investigated based on different models. The measurement was conducted at 28 GHz and 38 GHz frequencies for different scenarios. Results showed that the path loss exponent values were approximately identical at 28 GHz and 38 GHz for different scenarios of parking lots. It was found that the proposed compensation factor varied between 10.6 dB and 23.1 dB and between 13.1 and 19.1 in 28 GHz and 38 GHz, respectively. The proposed path loss models showed that more compensation factors are required for more scattering objects, especially at 28 GHz

Comparative study of indoor propagation model below and above 6 GHz for 5G wireless networks

It has been widely speculated that the performance of the next generation based wireless network should meet a transmission speed on the order of 1000 times more than the current cellular communication systems. The frequency bands above 6 GHz have received significant attention lately as a prospective band for next generation 5G systems. The propagation characteristics for 5G networks need to be fully understood for the 5G system design. This paper presents the channel propagation characteristics for a 5G system in line of sight (LOS) and non-LOS (NLOS) scenarios. The diffraction loss (DL) and frequency drop (FD) are investigated based on collected measurement data. Indoor measurement results obtained using a high-resolution channel sounder equipped with directional horn antennas at 3.5 GHz and 28 GHz as a comparative study of the two bands below and above 6 GHz. The parameters for path loss using different path loss models of single and multi-frequencies have been estimated. The excess delay, root mean square (RMS) delay spread and the power delay profile of received paths are analyzed. The results of the path loss models show that the path loss exponent (PLE) in this indoor environment is less than the free space path loss exponent for LOS scenario at both frequencies. Moreover, the PLE is not frequency dependent. The 3GPP path loss models for single and multi-frequency in LOS scenarios have good performance in terms of PLE that is as reliable as the physically-based models. Based on the proposed models, the diffraction loss at 28 GHz is approximately twice the diffraction loss at 3.5 GHz. The findings of the power delay profile and RMS delay spread indicate that these parameters are comparable for frequency bands below and above 6 GH

Investigation of the performances and the pollutant emissions characteristics of an in- direct injected four strokes, four cylinders engine using vegetable oils and their blends with diesel

Dans cette étude, les huiles de coton, de palme et de coprah, produites ou disponibles localement, sont utilisées sous forme pure ou sous forme de mélange au gas-oil dans un moteur diesel à injection indirecte (4 temps et 4 cylindres). L'évaluation des performances et des émissions polluantes est effectuée. Le comportement global de ces différentes huiles végétales ou leurs mélanges au gas-oil ainsi que leurs particularités par rapport au gas-oil pur sont mis en évidence. On note une baisse du couple et une augmentation de la consommation spécifique avec l'augmentation de la proportion d'huile végétale. Les émissions de monoxyde de carbone (CO) augmentent avec la proportion d'huile végétale dans le mélange en raison de l'augmentation de la viscosité et de la réduction de la volatilité. Quant aux émissions des oxydes d'azote (NOx), elles varient très peu pour l'ensemble des carburants testés. Enfin, les émissions directes de dioxyde de carbone (CO2) et de dioxyde de soufre (SO2) sont favorables aux huiles végétales ou leurs mélanges au gas-oil

Online signature verification approach using Mellin transform and empirical mode decomposition

International audienceThe signature is one of the most popular biometric modality. In this paper, we present a new method for online signature based on the use of the Mellin transform and the empirical mode decomposition (EMD) for online signature verification. A phase of pre-processing and normalization is carried out before the extracting of the signatures features by using the Mellin transform and the EMD. After that, three similarity measures are used to match the signatures where the signature verification competition (SVC 2004) is used as a database. Experimental results confirm the effectiveness of our approach and show the level of its reliability. Finally, the proposed method gives an EER of 2.13%

Modeling the emission of hydrogen chloride and free chlorine from the thermal treatment of polyvinyl chloride- (PVC-) based plastic materials

International audienceTo simulate the emission of hydrogen chloride gas and free chlorine from the thermal treatment of plastic materials, especially those based on PVC, two mathematical models have been developed. An experimental research program has been undertaken to validate these models. It is found that the masses of hydrogen chloride and free chlorine computed with these models are in good agreement with the experimental results. According to these results, it can be assumed that the quantity of hydrogen chloride and free chlorine produced during the thermal treatment of PVC-based materials strongly depends on the pyrolysis temperature and duration. The agreement between the results from simulations and empirical studies also shows the capability of these models to predict the amount of gas that will be produced from PVC-based materials upon thermal treatment

The Effect of Atmospheric Oxygen on the Puffing and Bursting Phenomena during Vegetable Oils Droplets Vaporization Process for Their Use as Biofuel in Diesel Engine

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Numerical Modeling and Study of Vaporization of Single Droplet and Mono-dispersed Spray Under Mixed Convection Conditions

An approach to account for combined convection during droplet evaporation and study of pure component droplets and mono-dispersed sprays is presented. The classical gas-phase and infinite conductivity liquid-phase model are extended, with the use of an effective Reynolds number, to conflate the combined effects of forced and natural convection. The current model, after validation with experimental and numerical data using an independent code, is incorporated into a commercial CFD software, ANSYS Fluent, via user-defined functions with the Eulerian–Lagrangian numerical scheme. A validation study is carried out by comparing with available experimental, numerical, and analytical data on pure component droplets and a mono-dispersed spray, respectively, for without and with droplet dynamics. The results are shown in terms of mass fraction, droplet velocity, droplet diameter square, and droplet temperature. The validation shows reasonably good match between the present numerical data and experimental and analytical data, respectively, for initial Red/Grd 0.09, 2.12, and 60 evaporating droplets/sprays. It is concluded that the biofuels, for example, ethanol with a lower latent heat of vaporization, burn much like mono-component droplets and the blowing effect can be important in their modeling in the spray combustion