Joint UAV Placement and IRS Phase Shift Optimization in Downlink Networks

This study investigates the integration of an intelligent reflecting surface (IRS) into an unmanned aerial vehicle (UAV) platform to utilize the advantages of these leading technologies for sixth-generation communications, e.g., improved spectral and energy efficiency, extended network coverage, and flexible deployment. In particular, we investigate a downlink IRS-UAV system, wherein single-antenna ground users (UEs) are served by a multi-antenna base station (BS). To assist the communication between UEs and the BS, an IRS mounted on a UAV is deployed, in which the direct links are obstructed owing to the complex urban channel characteristics. The beamforming at the BS, phase shift at the IRS, and the 3D placement of the UAV are jointly optimized to maximize the sum rate. Because the optimization variables, particularly the beamforming and IRS phase shift, are highly coupled with each other, the optimization problem is naturally non-convex. To effectively solve the formulated problem, we propose an iterative algorithm that employs block coordinate descent and inner approximation methods. Numerical results demonstrate the effectiveness of our proposed approach for a UAV-mounted IRS system on the sum rate performance over the state-of-the-art technology using the terrestrial counterpart

Joint Two-tier User Association and Resource Management for Integrated Satellite-Terrestrial Networks

peer reviewedThis paper investigates the uplink transmission of an integrated satellite-terrestrial network, wherein the low-earth-orbit (LEO) satellites provide backhaul services to isolated cellular base stations (BSs) for forwarding mobile user (UE) data to the core network. In this integrated system, the high mobility of LEO satellites (LEOSats) introduces significant challenges in managing radio resource allocation (RA), as well as the associations between UEs, BSs, and LEOSats for supporting users’ demands efficiently, while also dynamically balancing the capacity of UE-BS access and BS-LEO backhaul links. Regarding these critical issues, the paper aims to jointly optimize the two-tier UE-BS and BS-LEOSat association, sub-channel assignment, bandwidth allocation, and power control to meet users’ demands in the shortest transmission time. This optimization problem, however, falls into the category of mixed-integer non-convex programming, making it very challenging and requiring advanced solution techniques to find optimal solutions. To tackle this complex problem efficiently, we first develop an iterative centralized algorithm by utilizing convex approximation and compressed-sensing-based methods to deal with binary variables. Furthermore, for practical implementation and to offload computation from the central processing node, we propose a Dec-Alg that can be implemented in parallel at local controllers and achieve efficient solutions. Numerical results are also illustrated to strengthen the effectiveness of our proposed algorithms compared to traditional greedy and benchmark algorithms

Seamless 5G Automotive Connectivity with Integrated Satellite Terrestrial Networks in C-Band

peer reviewedThis paper examines integrated satellite-terrestrial networks (ISTNs) in urban environments, where terrestrial networks (TNs) and non-terrestrial networks (NTNs) share the same frequency band in the C-band which is considered the promising band for both systems. The dynamic issues in ISTNs, arising from the movement of low Earth orbit satellites (LEOSats) and the mobility of users (UEs), are addressed. The goal is to maximize the sum rate by optimizing link selection for UEs over time. To tackle this challenge, an efficient iterative algorithm is developed. Simulations using a realistic 3D map provide valuable insights into the impact of urban environments on ISTNs and also demonstrates the effectiveness of the proposed algorithm

On the Energy Efficiency Maximization of NOMA-Aided Downlink Networks With Dynamic User Pairing

n/

Research on deep geological structure and forecasting of some areas with petroleum prospects in the Red river delta coastal strip according to geophysical data

The coastal areas of the Red River Delta are the transition areas from the continent to the sea and have great mineral prospects, especially petroleum prospects. In this area, a lot of topics and projects in geology and geophysics have been conducted for many different purposes such as studying the deep structure, tectonic - geological features, seismic reflection - refraction to identify petroleum traps in the Cenozoic sediments... However there are very few studies on deep structure features, using the results of processing and meta-analysis of gravity, magnetotelluric, tectonic - geological data to detect the direct and indirect relations to the formation of structures with petroleum potential. The authors have researched, tested and applied an appropriate methodology of processing and analysis, to overcome the shortfall of gravity data as well as the nonhomogeneity in details of seismic and geophysical surveys. The obtained results are semi-quantitative and qualitative characteristics of structure of deep boundary surfaces, structural characteristics of fault systems and their distribution in the study area, calculation of the average rock density of pre-Cenozoic basement... From these results, the authors established the zoning map of the areas with petroleum potential in the Red river delta coastal strip according to geophysical data

Conservation, Exploitation And Use Of The Ginger Family (Zingiberaceae) At The National Genebank In Vietnam

There are 741 accessions in the ginger family such as turmeric, ginger, galangal, and pinecone ginger collections conserved at Plant Resources Center, Vietnam. These collections were highly diverse in the number of accessions and species composition. The results of the Zingiberaceae exploitation shown the G10 ginger variety plants reached around 63.7 - 77.5 cm in height, 400 - 500 g/clumps in fresh weight, 25 - 27 tonnes/ha in fresh yield. The G10 ginger variety contained 4.37% oil, 1.2 mg/kg Zn and 9.31 mg/100g Vitamin C. This G10 ginger variety resistance to leaf spot and green aphids. In addition, the N8 turmeric variety plants reached 130 - 170 cm in height; 880 - 1000 g/clumps in fresh weight and 35 tonnes/ha in yield, curcumin content 6.2 - 6.6%, essential oil contents 2.5 - 2.7%. This turmeric resistance to heat stress, leaf spot, and green aphids. The conserved root and tuber crops at PRC are very diverse both of the amount of sample in collections and species. Conservation and evaluation on root and tuber crops reviewed the promising G10 ginger and N8 turmeric varieties had high yield, good oil content to release for production

A FLEXIBLE HIGH-BANDWIDTH LOW-LATENCY MULTI-PORT MEMORY CONTROLLER

Multi-port memory controllers (MPMCs) have become increasingly important in many modern applications due to the tremendous growth in bandwidth requirement. Many approaches so far have focused on improving either the memory access latency or the bandwidth utilization for specific applications. Moreover, the application systems are likely to require certain adjustments to connect with an MPMC, since the MPMC interface is limited to a single-clock and single-data-width domain. In this paper, we propose efficient techniques to improve the flexibility, latency, and bandwidth of an MPMC. Firstly, MPMC interfaces employ a pair of dual-clock dualport FIFOs at each port, so any multi-clock multi-data-width application system can connect to an MPMC without requiring extra resources. Secondly, memory access latency is significantly reduced because parallel FIFOs temporarily keep the data transfer between the application system and memory. Lastly, a proposed arbitration scheme, namely window-based first-come-first-serve, considerably enhances the bandwidth utilization. Depending on the applications, MPMC can be properly configured by updating several internal configuration registers. The experimental results in an Altera Cyclone V FPGA prove that MPMC is fully operational at 150 MHz and supports up to 32 concurrent connections at various clocks and data widths. More significantly, achieved bandwidth utilization is approximately 93.2% of the theoretical bandwidth, and the access latency is minimized as compared to previous designs

When Intervention Becomes Imperative: A Case Report of Spontaneous Vulvar Edema During Pregnancy

Spontaneous idiopathic vulvar edema during the second trimester is a rare condition. The approach to managing this condition involves relieving symptoms, identifying underlying causes, and implementing appropriate treatment. Managing such cases during pregnancy is challenging because of concerns for potential adverse fetal outcomes. Conservative management expects the condition to be relieved spontaneously postpartum, whereas invasive treatment offers a more rapid resolution. Treatment choices are controversial because each method has its pros and cons and influences the delivery process to a certain extent. Surgical drainage becomes a viable option when patients are not responsive to medications. We report a case of spontaneous massive vulvar edema in a 22-year-old primigravida in her 23rd week of pregnancy. After ruling out other notable causes of vulvar edema, we decided to intervene using an invasive procedure because she complained of progressive symptoms and discomfort. Subsequently, the edema subsided postprocedure, and the patient experienced successful labor with no complications. This report aims to alert clinicians that drainage attempts should be considered in pregnant patients with worsening symptoms