For the aim of surface refractivity analysis, the overall territory of Quebec has been divided in a desired number of areas from North to South using clustering analysis. The meteorological data used in the analysis are collected from 50 stations located in various climatic regions over Quebec for the year 2013. It is found that the best input data for the identification of areas is the water vapour pressure. The results show that the surface refractivity increase from North to South and the maximum values for all areas are observed in July or in August. However, the variation of the surface refractivity remains in a relatively small interval in comparison to the variation observed in some tropical countries, particularly Nigeria.

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Journal: Journal of Atmospheric and Solar-Terrestrial Physics Volume 208

A survey of indoor propagation characteristics is presented, including different models for path loss, shadowing and fast fading mechanisms, different channel parameters including signal strength, power delay, coherence bandwidth, Doppler spread and angle of arrival. The concepts of MIMO channels are also covered. The study also explores many types of deterministic channel modelling, such as Finite Difference Time Domain, Finite Integration Method, Ray tracing and the Dominant path model. Electromagnetic properties of building materials, including frequency dependence, are also investigated and several models for propagation through buildings are reviewed.

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Journal: Computer Science Review Volume 37, August 2020, 100272

In this paper, a comparative study between different indoor path loss prediction models is conducted. The investigated models include averaged wall loss model (AWM), single slope model (SSM), linear attenuation model (LM), two slope model (TSM), partitioned model (PM), and Motley-Keenan model (MKM). The models were tested in a simulated environment of the 3rd floor of Chesham building, the University of Bradford, a different set of frequencies were used including 28 GHz, 60 GHz, and 73.5 GHz, TSM shows the best performance, both AWM and MKM tend to have a similar performance at millimetrefrequencies, both models’ prediction for corridor and LOS regions are pessimistic while TSM, SSM, and LM have better estimations in these regions.

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Journal: ACES volume 35 issue 2

This study describes the investigation that carried out to study the effects of Cement, gypsum and wheat husk ash on compaction properties of the clayey soil. Inorganic clay with low Plasticity was used in this study as a natural soil. For this purpose a series of laboratory experiments have been implemented and varieties of samples were made by mixing cement, gypsum and wheat husk ash with natural soil. Three different percentages of gypsum and wheat husk ash (3%, 6% and 9%) used as stabilization materials. The results demonstrated that adding cement has a significant effect on increasing the degree of compaction of the soil samples. In general, the results show that the performance of cement-stabilized soils was superior to gypsum in all the characterizations performed.

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Journal: International Journal of Current Research

Alternative healthcare solutions have been identified as a viable approach to ameliorate the increasing demand for telehealth and prompt healthcare delivery. Moreover, indoor ocalization using dierent technologies and approaches have greatly contributed to alternative healthcare solutions. In this paper, a cost-eective, radio frequency identification (RFID)-based indoor location system that employs received signal strength (RSS) information of passive RFID tags is presented. The proposed system uses RFID tags placed at dierent positions on the target body. The mapping of the analysed data against a set of reference position datasets is used to accurately track the vertical and horizontal positioning of a patient within a confined space in real-time. The Euclidean distance model achieves an accuracy of 98% for all sampled activities. However, the accuracy of the activity recognition algorithm performs below the threshold performance for walking and standing, which is due to similarities in the target height, weight and body density for both activities. The obtained results from the proposed system indicate significant potentials to provide reliable health measurement tool for patients at risk.

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Journal: Future Internet Volume 12 Issue 2

Thirty‐nine years of archived meteorological data measured at two stations located in the northern and southern parts of Quebec, Canada are used to estimate the surface refractivity and its dry and wet components. The results of the comparison of the obtained estimates showed that for all months the values of the dry component are higher in the northern part, whereas the values of the wet component are higher in the southern part. Due to this, for several months of the year, the values of the surface refractivity are higher in the northern part and for the remaining months in the southern part. Moreover, in both parts, August is the month where the highest values of the surface refractivity were recorded. In this particular month, the slope of the surface refractivity trend in the northern part is several times higher than that in the southern part. The obtained results show that the performance of the used direct smoothing forecasting technique depends on the deviation between the values of N in the current year and the previous year.

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Journal: Radio Science, Volume 55, Issue 7

In this paper, local meteorological data of one year have been used to calculate the surface atmospheric radio refractivity (N) and estimate the vertical refractivity gradient (dN 1) as well as the geoclimatic factor (K) in the lowest atmospheric layer above the ground surface in the station Kuujjuaq (Quebec, Canada). In this region, the climate is arctic, characterized by very long and very cold winters (on average the temperature is below −20◦C for almost 240 days per year). The precipitations are almost nonexistent, and the vegetation is scarce. Average daily, monthly, seasonal, and yearly variations of N, dN 1, and K are estimated and analysed. The obtained values of these indices are compared to the corresponding values provided by the ITU. The results show that the more negative values of dN 1 lie in the summer season. This is mainly due to the important variations of the temperature and humidity during this season. However, the estimated values lie in the limits mostly corresponding to standard refraction.

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Journal: Progress In Electromagnetics Research M, Vol. 92, 181–192, 2020

A new compact Cylindrical Dielectric Resonator Antenna (CDRA) with a defected ground for ultra-wideband applications is presented. The structure is based on two cylindrical dielectric resonators asymmetrically located with respect to the center of an offset rectangular coupling aperture, with consideration of three and four Dielectric Resonators (DR). The resonant modes generated by the defected ground are studied and investigated. A parametric optimization study of the antenna design has been carried out to determine the optimal dimensions of the defected ground plane, resulting in an impedance bandwidth of over 133% that covers the frequency band from 3.6 GHz to 18.0 GHz. A power gain of about 7.9 dBi has been achieved. Design details and measured and simulated results are presented and discussed

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Journal: IEEE Access

Gravity retaining walls are known to be relatively economic as retaining solution to the heights up to 4m.Gravity walls depend on their mass (stone, concrete) to resist pressure from behind the walls. Many shape gravity retaining walls are used; rectangular, triangular, and trapezoidal. This study focuses on finding the optimum shape design for retaining walls. The cost of the gravity retaining walls depends on the weight and the materials. In order to minimize the cost, materials of the gravity retaining walls should be minimized, which mean that the section of gravity retaining walls must be reduced. The design starts by choosing the shape of gravity walls for which the stability of the wall is checked. To study the effect of shape on minimizing the weight or volume (Area) many sections were used. In the present work the result of a numerical analysis is presented. The results show that the rectangular retaining wall shape has a large volume which in turn it has a large weight equal to100 %from the total weight ,triangular shape has 73 % from the total weight, and trapezoidal shape has 52 % from the total weight with better stability against the soil which is the most economical shape of gravity retaining walls.

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Journal: International Journal of Innovative Science and Modern Engineering

The potential for using fly ash as a supplementary cementing material in concrete has been known almost since the beginning of the previous century. Fly ash was used as a supplementary cementing material (SCM) in the production of Portland cement concrete. A supplementary cementing material, when used in conjunction with Portland cement, contributes to the properties of the hardened concrete through hydraulic or pozzolanic activity, or both. In this study, the fly ash and waste glass powder were used in concrete blocks to study the improvement of concrete in terms of workability and strength. Therefore, an experimental study will be conducted to measure the engineering properties of cured concrete. In this research, local raw material from Jaresh area was used.

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Journal: Open Journal of Civil Engineering