Cone Penetration Testing For Field Density Prediction

This paper summarizes an experimental program for developing a pilot procedure to check and predict field densities of compacted soils using static cone penetration tests. Three sandy soils were tested. The testing program included both laboratory and field tests. On the basis of laboratory tests, density prediction curves were developed while field results were used to find a correlation to predict densities on the basis of measured penetration resistances. The results are rather encouraging and promising. It is anticipated that the presented methodology would be very effective for compaction quality control in large areas of sandy soils because it is fast, simple and causes minimum disturbance to the compacted soil

Spatial domain modeling of microcellular systems operating in multipath Nakagami channels

In conventional channel models, the AoA's at the BS, are assumed to be uniformly distributed. However, measurements in urban areas have shown non-uniform AoA distributions. In this paper, the spatial characterization of wideband urban mobile radio channels is investigated and the resulting and spatial correlations at the BS receiver are computed. A geometrically based modeling is used to spatially characterize both TU and BU environments. The clustered scatterers are assumed to have bivariate Gaussian densities. The AoA pdf's are derived. The spatial correlations are computed for tooth environments and the effects of the channel parameters such as the scatterer's variance, the BS-MS distance, the mean angle of arrival on these correlations are investigated

Vision-Assisted User Clustering for Robust mmWave-NOMA Systems

When operated in the mmWave band, user channels get highly correlated which can be exploited in mmWave-NOMA systems to cluster a set of "correlated" users together. Identifying the set of users to cluster greatly affects the viability of NOMA systems. Typically, only channel state information (CSI) is used to make these clustering decisions. When any problem arises in accessing up-to-date and accurate CSI, user clustering will not properly function due to its hard-dependency on CSI, and obviously, this will negatively affect the robustness of the NOMA systems. To improve the robustness of the NOMA systems, we propose to utilize emerging trends such as location-aware and camera-equipped base stations (CBSs) which do not require any extra radio frequency resource consumption. Specifically, we explore three different dimensions of feedback that a CBS can benefit from to solve the user clustering problem, namely CSI-based feedback and non-CSI-based feedback, comprised of user equipment (UE) location and the CBS camera feed. We first investigate how the vision assistance of a CBS can be used in conjunction with other dimensions of feedback to make clustering decisions in various scenarios. Later, we provide a simple user case study to illustrate how to implement vision-assisted user clustering in mmWave-NOMA systems to improve robustness, in which a deep learning (DL) beam selection algorithm is trained on the images captured by the CBS to perform NOMA clustering. We demonstrate that user clustering without CSI can achieve comparable performance to accurate CSI-based solutions, and user clustering can continue to function without much performance loss even in the scenarios where CSI is severely outdated or not available at all.Comment: Accepted in the Proceedings of IEEE Future Networks World Forum (IEEE FNWF 2020

Investigation of Natural Effective Gamma Dose Rates case study: Ardabil Province in Iran

Gamma rays pose enough energy to form charged particles and adversely affect human health. Since, the external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined, natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardabil province from 2009 to 2010. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed dose for Ardabil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSvh-1, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardabil province was estimated to be 1.73 (1.35-2.39) mSv, which is on average 2 times higher than the world population weighted average

Multi-user visible light communications: State-of-the-art and future directions

Visible light communications (VLC) builds upon the dual use of existing lighting infrastructure for wireless data transmission. VLC has recently gained interest as cost-effective, secure, and energy-efficient wireless access technology particularly for indoor user-dense environments. While initial studies in this area are mainly limited to single-user point-to-point links, more recent efforts have focused on multi-user VLC systems in an effort to transform VLC into a scalable and fully networked wireless technology. In this paper, we provide a comprehensive overview of multi-user VLC systems discussing the recent advances on multi-user precoding, multiple access, resource allocation, and mobility management. We further provide possible directions for future research in this emerging topic.King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia ; TÜBİTAKPublisher versio