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

Teaching Ways and Learning Ways Revisited

In learning and teaching of languages, numerous theories have been put forward. These theories, normally influenced by developments in the fields of linguistics and psychology, have inspired several approaches to the teaching of second and foreign languages. This paper revisits English language teaching approaches, both traditional and modern, as well as learning styles and teaching styles. Such learning style models as The Myers-Briggs Type Indicator (MBTI); Kolb’s Experiential Learning Model; the Felder-Silverman Learning Styles Model are explored in-depth in this paper. Keywords: teaching approach; learning style; teaching styl

Back analysis of a coupled thermo-hydro-mechanical model based on instrumented constant volume column test

This study contributes to identification of the constitutive model parameters for coupled THM models for unsaturated sand-bentonite mixtures via back analysis approach. The approach strategy consists of: definition of the forward model, sensitivity analysis, selection of optimization algorithm, selection of a set of parameters to be optimized, setup of the parameter’s constraints, and assessing the reliability and accuracy of the identified model and material parameters. For this analysis the iterative direct approach based on numerical solution of the direct problem and minimization of an objective function has been selected. It is given an example of application of the selected inverse analysis procedure to identification of parameters involved in a modified Barcelona Basic Model taking into account of variation of temperature

On the Electrostatic Forces acting on Point Charges in the Presence of a Dielectric Slab

How will the electrostatic interaction between two point charges change if we introduce a dielectric slab in the middle of them? While the physical setting of this problem is relatively simple, it is easy to be wronged and the solution is surprisingly complicated. Here we will show the correct answer by using the method of images, which should be approachable for undergraduate students and advance high school students. We also obtain analytical and algebraic results in some special cases

Properties of Concrete Containing Rubber Aggregate Derived From Discarded Tires

This study carried out the experiment to evaluate the effects of different contents and sizes of rubber particles derived from discarded tires used for replacing fine and coarse natural aggregates, on the workability of fresh rubberized concrete and the compressive and flexural strengths of hardened rubberized concrete. The study results showed that the workability of fresh rubberized concrete was improved when replacing natural fine aggregate (sand) with fine rubber particles (2.5-5 mm) at the replacing proportions of 30-50% by volume, and when replacing natural coarse aggregate (crushed stone) with coarse rubber particles (5-20 mm) at the replacing proportions of 10-30% by volume. With respect to the mechanical properties of hardened rubberized concrete, a larger reduction in the compressive and flexural strengths was generally found when the replacing proportions increased and when coarse aggregate rather than fine aggregate was replaced by rubber particles at all replacing proportions (10-50%). However, the study results also indicated that using fine rubber particles for replacing fine natural aggregate at the low replacing proportion (up to 10%) might not cause the significant effect on the compressive and flexural strength of rubberized concrete

Effect of Creep and Shrinkage model in calculation of long-term deflection of three-span solid slab continuous prestressed concrete bridge

Shrinkage and creep effect significantly to the long-term deflection of prestressed concrete bridge. The proper shrinkage and creep models should be developed to meet the requirements of deflection effect calculation. There are many models has been researched and developed. Each specification, such as ASSHTO, Eurocode, ACI and CEB-FIB, has their own model of shrinkage and creep by considering different input parameter. The long-term deflection calculation is also different in each specification as a result. In this paper, several shrinkage and creep models were selected and reviewed to see the difference and compare by using popular concrete grade in Vietnamese bridge building     (C40 and C45, equivalent to 40 and 45 Mpa, respectively). Those selected shrinkage and creep models are applied in calculation of deflection for a typical three-span continuous solid slab prestressed concrete bridge. The calculation result show the significant different of long-term deflection and the ASSHTO shrinkage and creep model show the biggest deflection

Effect of Creep and Shrinkage model in calculation of long-term deflection of three-span solid slab continuous prestressed concrete bridge

Shrinkage and creep effect significantly to the long-term deflection of prestressed concrete bridge. The proper shrinkage and creep models should be developed to meet the requirements of deflection effect calculation. There are many models has been researched and developed. Each specification, such as ASSHTO, Eurocode, ACI and CEB-FIB, has their own model of shrinkage and creep by considering different input parameter. The long-term deflection calculation is also different in each specification as a result. In this paper, several shrinkage and creep models were selected and reviewed to see the difference and compare by using popular concrete grade in Vietnamese bridge building     (C40 and C45, equivalent to 40 and 45 Mpa, respectively). Those selected shrinkage and creep models are applied in calculation of deflection for a typical three-span continuous solid slab prestressed concrete bridge. The calculation result show the significant different of long-term deflection and the ASSHTO shrinkage and creep model show the biggest deflection

NUMERICAL SIMULATION AND INVERSE ANALYSIS OF THERMO-HYDRO-MECHANICAL BEHAVIOR OF SAND-BENTONITE MIXTURE

Sand-bentonite mixtures are well recognized as buffer and sealing material in nuclear waste repository constructions. The behaviour of compacted sand-bentonite mixture needs to be well understood in order to guarantee the safety and the efficiency of the barrier construction. This paper presents numerical simulations of swelling test and coupled thermo-hydro-mechanical (THM) test on compacted sand-bentonite mixture in order to reveal the influence of the temperature and hydraulic gradients on the distribution of temperature, mechanical stress and water content in such materials. Sensitivity analysis is carried out to identify the parameters which influence the most the response of the numerical model. Results of back analysis of the model parameters are reported and critically assessed

The Higgs Sector of the Minimal 3 3 1 Model Revisited

The mass spectrum and the eigenstates of the Higgs sector of the minimal 3 3 1 model are revisited in detail. There are discrepancies between our results and previous results by another author.Comment: 20 pages, latex, two figures. One note and one reference are adde

Federated Deep Reinforcement Learning-based Bitrate Adaptation for Dynamic Adaptive Streaming over HTTP

In video streaming over HTTP, the bitrate adaptation selects the quality of video chunks depending on the current network condition. Some previous works have applied deep reinforcement learning (DRL) algorithms to determine the chunk's bitrate from the observed states to maximize the quality-of-experience (QoE). However, to build an intelligent model that can predict in various environments, such as 3G, 4G, Wifi, \textit{etc.}, the states observed from these environments must be sent to a server for training centrally. In this work, we integrate federated learning (FL) to DRL-based rate adaptation to train a model appropriate for different environments. The clients in the proposed framework train their model locally and only update the weights to the server. The simulations show that our federated DRL-based rate adaptations, called FDRLABR with different DRL algorithms, such as deep Q-learning, advantage actor-critic, and proximal policy optimization, yield better performance than the traditional bitrate adaptation methods in various environments.Comment: 13 pages, 1 colum