Real-time Optimal Resource Allocation for Embedded UAV Communication Systems

We consider device-to-device (D2D) wireless information and power transfer systems using an unmanned aerial vehicle (UAV) as a relay-assisted node. As the energy capacity and flight time of UAVs is limited, a significant issue in deploying UAV is to manage energy consumption in real-time application, which is proportional to the UAV transmit power. To tackle this important issue, we develop a real-time resource allocation algorithm for maximizing the energy efficiency by jointly optimizing the energy-harvesting time and power control for the considered (D2D) communication embedded with UAV. We demonstrate the effectiveness of the proposed algorithms as running time for solving them can be conducted in milliseconds.Comment: 11 pages, 5 figures, 1 table. This paper is accepted for publication on IEEE Wireless Communications Letter

Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems

It is well-known that the traditional transmit beamforming at a base station (BS) to manage interference in serving multiple users is effective only when the number of users is less than the number of transmit antennas at the BS. Non-orthogonal multiple access (NOMA) can improve the throughput of users with poorer channel conditions by compromising their own privacy because other users with better channel conditions can decode the information of users in poorer channel state. NOMA still prefers that the number of users is less than the number of antennas at the BS transmitter. This paper resolves such issues by allocating separate fractional time slots for serving the users with similar channel conditions. This enables the BS to serve more users within the time unit while the privacy of each user is preserved. The fractional times and beamforming vectors are jointly optimized to maximize the system's throughput. An efficient path-following algorithm, which invokes a simple convex quadratic program at each iteration, is proposed for the solution of this challenging optimization problem. Numerical results confirm its versatility.Comment: IEEE Communications Letters (To Appear

Smectic Liquid Crystal Freely Suspended Films: Testing Beds for the Physics in Thin Membranes

This thesis highlights the unique features of smectic liquid crystal freely suspended films to study surface effects and two-dimensional physics via three experiments: the first confirms the popular Saffman-Delbruck theory of the drag on a small cylinder in a thin membrane, the second measures the surface tension of a freely suspended molecular monolayer, and the third is a high-speed observation of the coalescence of two thin fluid disks. In the first experiment, we measure the diffusion constant of thicker domains (islands) in the film. They are perfectly circular and are readily observed under the microscope, making it possible to track the motion of their centers with high precision (~10 nm). In the second experiment, the imposed symmetry on a smectic monolayer helps to detect surface induced asymmetry on bilayer and thicker films via the motion of 1D interfaces between domains of different thicknesses. Lastly, in the third experiment, the high contrast of the film under reflection microscopy helps to capture the coalescence at high speed without introducing much noise at low light levels. Moreover, without the obstruction of any substrate, an optical trap can be effectively used to manipulate islands to force coalescence rather than having to wait for serendipitous events

Experiences of Renal Stone Fragmentation with the Use of the Ultrasound-guided Mini-percutaneous Nephrolithotipsy in 650 Patients

AIM: This study assesses the results of treatment using the mini-percutaneous nephrolithotipsy (PCNL) procedure on renal stone patients in a lateral position under ultrasound guidance, performed at the Ha Noi Hospital of Post and Telecommunications. METHODS: The study was conducted with 650 kidney stone patients who were treated using the ultrasound-guided mini-PCNL procedure in a lateral position, at the Ha Noi Hospital of Post and Telecommunications, over the period from June 2018 to June 2019. RESULTS: For the 650 patients, the mean age was 47.3 ± 7.6 (from 21 to 91 years old); the mean size of stones: 19.4 ± 1.2 mm (from 12 mm to 60 mm); the mean operative time: 49.3 minutes (from 37 to 90 min); the mean period of hospitalization: 3.9 days (from 3 to 12 days); the mean stone-free rate (SFR): 90.6%; the rate of second surgery: 1.07%; hemorrhage complication: 0.8%; urinary tract infections: 7.7%; septicemia: 0.6%; administered open surgery: 0.46%; and administered other methods: 0.76%. CONCLUSION: Renal stone fragmentation using the mini-PCNL procedure, performed on patients placed in lateral position under ultrasound guidance, is a method that is effective, beneficial, and safe for patients with renal stones and upper ureteral stones

Web Page Transformation to Vector Graphics

Táto bakalárska práca sa venuje problematike vykreslenia webových stránok pomocou vektorovej grafiky. Cieľom tejto práce je navrhnúť a implementovať rozšírenie projektu WebVector tak, aby umožňoval vytvoriť výstup vo formáte PDF a vykresliť vybrané pokročilé vlastnosti CSS (CSS3). Vysvetlené sú pojmy súvisiace s vektorovou grafikou a jej formátmi. Práca následne popisuje štruktúru a funkcie knižnice CSSBox, s ktorou projekt WebVector pracuje, spolu s ďalšími súvisiacimi knižnicami. Ďalej je popísaných niekoľko CSS3 vlastností, ich návrh a implementácia na platforme Java.This bachelor thesis is devoted to the problem of rendering websites with vector graphics. The goal of this thesis is design and implement an extension of the WebVector project, which allows creating the output in PDF format and rendering some specific CSS3 properties. The terms related to vector graphics and its formats are explained. This work describes the structure and features of the CSSBox library, which project WebVector works with, and other related libraries. Then some of the CSS3 properties and also their design and implementation in platform Java are detailly described.

Costs and Benefits of a Greener Alternative for the Development of Vietnam's power sector

International audienceIn this study, BAU (a scenario based on current trends) and ALT (a greener alternative with more renewables, higher energy efficiency) are developed. The external costs of CO 2 , NOx, SO 2 and PM 10 in the Vietnamese power sector are estimated at 20, 1328, 2047 and 1460 US$/ton, respectively. The authors find that the electricity price and the domestic trade balance in ALT are less sensitive to fluctuations in the international price of coal than in BAU. The total costs accumulated between period 2010-2040 would be lower in ALT: 632 billion US$ compared with 974 billion US$. This difference arises from several factors: lower investment in new capacity (226 vs 306 billion US$); lower local pollution costs (73 vs 137 billion US$); and lower expenditures on imported fuels (57 vs 115 billion US$). The outcomes of ALT are in accord with the targets in the most recent Green Growth Strategy of Vietnam