Relay Technique Research Articles

What makes a successful relay start in swimming?

ABSTRACT Despite the mechanical advantage of preparatory movements on the starting block, current evidence questions the start improvements of competitive swimmers with their relay techniques. Therefore, the aim of the present study was to analyse the kinetic and kinematic parameters of a successful relay start. Twenty national- and international-level swimmers performed several relay starts (n = 145) with their preferred technique (short or long-step start) over an instrumented OBS11 starting platform. Trials were classified as successful or non-successful depending on the 10-m times being faster or slower than their individual start. Linear Mixed Models outlined that successful relay starts were characterised (all p < 0.05) by a later (0.04 s) onset of the leg step, a lower (18%) horizontal force during the leg step, and a later (0.03 s) positioning of the hands at the lowest point of the upper-limb backswing. In addition, greater values for the maximal horizontal (12%) and vertical (9%) forces and faster horizontal (4%) and resultant (3%) velocities were detected when driving off the block. These characteristics were also dependent on the relay technique. Unlike individual track starts, swimmers with fast relay starts employed longer preparatory movements on the block to maximise the time of force application and thus the impulse.

An Improved Protective Relaying Technique for Transmission Line Connected With UPFC and DFIG-Based Wind Farm

An Improved Protective Relaying Technique for Transmission Line Connected With UPFC and DFIG-Based Wind Farm

Sequence-Specific Relay Recognition of Multiple Anions: An Interplay between Proton Donors and Acceptors.

Ratiometric detection of analyte is highly deserving since the technique is free from background correction. This work reports the design and synthesis of a pyridine-end oligo p-phenylenevinylene (OPV) derivative, 1 and its application in ratiometric dual-mode (both colorimetric and fluorogenic) recognition of dual anions, bisulfate (LOD=12.5 ppb) followed by fluoride (LOD=18.2 ppb) by sequence-specific relay (SPR) technique. The colorless probe turns brown with addition of bisulfate and again becomes colorless with the sequential addition of fluoride ion. In addition to such naked-eye color change, interestingly the ratiometric spectroscopic signals are reversible and evidently, the probe is reusable for several cycles. Besides, in presence of bisulfate, the protonated probe molecules, owing to their larger amphiphilic characteristics, formed self-assembled nanostructures. In addition to colorimetric and fluorescent changes, 1 H NMR titration and systematic DFT study evidently establish the underneath proton transfer mechanisms. Such reusable OPV-based chemosensor particularly with the capability of naked-eye recognition of dual anions using the SPR technique is seminal and possibly the first report in the literature.

Time-slot based architecture for power beam-assisted relay techniques in CR-WSNs with transceiver hardware inadequacies

Time-slot based architecture for power beam-assisted relay techniques in CR-WSNs with transceiver hardware inadequacies

A Deep Reinforcement-Learning-Based Relay Selection for Underwater Sensors Network

Abstract Due to their limited frequency range and fast fading channels, underwater sensor networks (USNs) are vulnerable to collisions of packets. In this paper, we propose a deep reinforcement learning-based relay selection scheme with shortest latency (DRL-SL) for USNs that enables to choose the relay based on the state that comprised of the bit error rate (BER) of the previous transmission, and the jamming power measured by the relay node. The DRL-SL-based relay selection scheme completed in two phases. In the first phase, a deep neural network based learning is performed and second phase is the real-time interaction with the underwater sensor network. Numerical results give the bound on how efficiently the system performs in terms of bit error rate, energy use, and node utility. According to the numerical results, the proposed DRL-SL based relay selection scheme can enhance relay performance in comparison to the benchmark underwater relay techniques.

Opportunistic Relaying Technique over Rayleigh Fading Channel to Improve Multicast Security

Opportunistic Relaying Technique over Rayleigh Fading Channel to Improve Multicast Security

Completion Delay of Random Linear Network Coding in Full-Duplex Relay Networks

As the next-generation wireless networks thrive, full-duplex and relay techniques are combined to improve the network performance. Random linear network coding (RLNC) is another popular technique to enhance the efficiency and reliability of wireless communications. In this paper, in order to explore the potential of RLNC in full-duplex relay networks, we investigate two fundamental perfect RLNC schemes and theoretically analyze their completion delay performance. The first scheme is a straightforward application of conventional perfect RLNC studied in wireless broadcast, so it involves no additional process at the relay. Its performance serves as an upper bound for all perfect RLNC schemes. The other scheme allows sufficiently large buffer and unconstrained linear coding at the relay. It attains the optimal performance and serves as a lower bound for all RLNC schemes. For both schemes, closed-form formulae to characterize the expected completion delay at a single receiver as well as for the whole system are derived. Numerical results are also demonstrated to validate the theoretical characterizations, and compare the two fundamental schemes with the existing one.

Knowledge Retention Using "Relay": A Novel Active-Learning Technique.

Many residency programs utilize passive didactic lectures despite mixed evidence for knowledge retention. This prospective study investigated the efficacy of "relay," an active-learning technique, as measured by residents' knowledge retention and attitudes compared to traditional format. Faculty presented lectures to four family medicine residency programs on a randomized schedule. Lectures were followed by a 15-minute question-and-answer (Q&A) session or relay session. A relay is a collaborative, question-based game. The primary outcome was knowledge retention at 3 months, comparing Q&A to relay sessions as measured by a multiple-choice assessment. Responses were only included if a given resident completed knowledge assessments for both Q&A and relay sessions, to allow for intraresident adjustments, in addition to program, training year, and lecturer/topic. Secondary outcomes included residents' self-perceived knowledge and engagement as surveyed by an ordinal scale immediately following the learning session. The primary analysis included 51 responses from 18 unique residents. The adjusted mean knowledge assessment score at 3 months was not statistically different after the relay sessions compared to Q&A (67% vs 60%, respectively; 7% difference, 95% CI: -4 to 18%, P=.20). For the secondary outcomes of learner attitudes (n=143 responses), learners reported greater engagement after the relay sessions compared to Q&A (51% vs 28% "very engaged"; overall P=.003), but self-perceived knowledge was not significantly different (overall P=.05, rounded down). The relay technique did not show significant difference in 3-month knowledge retention, nor immediate self-perceived knowledge, despite greater learner self-perceived engagement.

MmWave relay systems with robust hybrid transceiver designs under correlated channel estimation errors

In this paper, we incorporate mmWave systems with relay techniques to propose a hybrid transceiver design approach. The existing researches of hybrid transceiver designs mostly rely on accurate channel state information acquisitions. However, it is hard to avoid estimation errors in practice, which motivates us to propose a robust design based on imperfect channel estimations. We first design the fully digital processors and then decompose them into hybrid ones. An alternating algorithm is proposed to solve the fully digital processors by utilizing the relationship between the maximization of the upper bound of the averaged mutual information and the weighted minimum mean squared error problem. A decomposition algorithm with closed-form solutions is also proposed to obtain hybrid processors with analog-digital-analog structure at the relay terminal. Compared with related works, the proposed decomposition algorithm outperforms existing decomposition methods under imperfect CSI condition and the proposed hybrid design sacrifices certain complexity to achieve obvious performance improvements, which are illustrated by numerical simulations.

Performance analysis of cooperative NOMA system for defense application with relay selection in a hostile environment

In the current scenario, where all the services have become online, the demand for increased capacity, low symbol error rate (SER), better data rate, and low latency with high quality of services has been expected from the service providers. Non-orthogonal multiple access (NOMA) is the key enabling technology by which all the above requirements could be achieved. In this work, the physical layer security of a cooperative NOMA system has been improved. The present approach of the decode-and-forward (DF) method consists of one base station (BS), N relays, and two users. Here, a two-stage relay method has been proposed, and analytical results are generated to show that this two-stage relay scheme has been found to achieve the lowest outage probability among all possible relay schemes with the highest attainable diversity gain. In a high signal-to-noise ratio (SNR), the asymptotic and closed-form expressions for outage probability have been obtained. The outage probability for N relays is also computed, which shows that the outage probability decreases as the number of relays get increased. Meanwhile, the Monte-Carlo simulation shows that cooperative NOMA with the proposed two-stage relay technique outperforms cooperative NOMA using the traditional max-min approach.

Performance Analysis of OLSR Protocol in Mobile Ad Hoc Networks

Optimized Link State Routing Protocol (OLSR) is an efficient routing protocol used for various Ad hoc networks. OLSR employs the Multipoint Relay (MPR) technique to reduce network overhead traffic. A mobility model's main goal is to realistically simulate the movement behaviors of actual users. However, the high mobility and mobility model is the major design issues for an efficient and effective routing protocol for real Mobile Ad hoc Networks (MANETs). Therefore, this paper aims to analyze the performance of the OLSR protocol concerning various random and group mobility models. Two simulation scenarios were conducted over four mobility models, specifically the Random Waypoint model (RWP), Random Direction model (RD), Nomadic Community model (NC), and the Reference Point Group Model (RPGM) with a low as well as high random range mobility of the nodes. Moreover, BonnMotion Software and Network simulator NS-3 used to implement the simulation scenarios. Further, the performance of the OLSR protocol analyzed and evaluated based on latency, routing overhead, and packet loss ratio metrics. According to the results, the OLSR protocol provides the best performance over the RWP model in a low mobility environment, whereas the Nomadic mobility model is suitable for OLSR protocol in a high mobility environment.

Hybrid AF/DF Cooperative Relaying Technique with Phase Steering for Industrial IoT Networks

For the next generation of manufacturing, the industrial internet of things (IoT) has been considered as a key technology that enables smart factories, in which sensors transfer measured data, actuators are controlled, and systems are connected wirelessly. In particular, the wireless sensor network (WSN) needs to operate with low cost, low power (energy), and narrow spectrum, which are the most technical challenges for industrial IoT networks. In general, a relay-assisted communication network has been known to overcome scarce energy problems, and a spectrum-sharing technique has been considered as a promising technique for the radio spectrum shortage problem. In this paper, we propose a phase steering based hybrid cooperative relaying (PSHCR) technique for the generic relay-assisted spectrum-shared WSN, which consists of a secondary transmitter, multiple secondary relays (SRs), a secondary access point, and multiple primary access points. Basically, SRs in the proposed PSHCR technique operate with decode-and-forward (DF) relaying protocol, but it does not abandon the SRs that failed in decoding at the first hop. Instead, the SRs operate with amplify-and-forward (AF) protocol when they failed in decoding at the first hop. Furthermore, the SRs (regardless of operating with AF or DF protocol) that satisfy interference constraints to the primary network are allowed to transmit a signal to the secondary access point at the second hop. Note that phase distortion is compensated through phase steering operation at each relay node before second-hop transmission, and thus all relay nodes can operate in a fully distributed manner. Finally, we validate that the proposed PSHCR technique significantly outperforms the existing best single relay selection (BSR) technique and cooperative phase steering (CPS) technique in terms of outage performance via extensive computer simulations.

Carboxylic acids as anchoring components on aluminum oxide for the alignment relay technique of single-walled carbon nanotubes

We illustrate using a carboxylic acid anchoring component in the Alignment Relay Technique on silica and alumina surfaces. We present theoretical calculations on the interactions between the iptycenes' various pockets and the carbon nanotubes.

Task Scheduling in Cloud Using Deep Reinforcement Learning

Cloud computing is an emerging technology used in many applications such as data analysis, storage, and Internet of Things (IoT). Due to the increasing number of users in the cloud and the IoT devices that are being integrated with the cloud, the amount of data generated by these users and these devices is increasing ceaselessly. Managing this data over the cloud is no longer an easy task. It is almost impossible to move all data to the cloud datacenters, and this will lead to excessive bandwidth usage, latency, cost, and energy consumption. This makes it evident that allocating resources to users’ tasks is an essential quality feature in cloud computing. This is because it provides the customers or the users with high Quality of Service (QoS) with the best response time, and it also respects the established Service Level Agreement. Therefore, there is a great importance of efficient utilization of computing resources for which an optimal strategy for task scheduling is required. This paper focuses on the problem of task scheduling of cloud-based applications and aims to minimize the computational cost under resource and deadline constraints. Towards this end, we propose a clipped double deep Q-learning algorithm utilizing the target network and experience relay techniques, as we as using the reinforcement learning approach.

A Kinematics Comparison of Different Swimming Relay Start Techniques

ABSTRACT In swimming relay races, various start techniques are performed by swimmers, but it remains unclear which technique leads to a better start performance. Therefore, the purpose of the present study was to compare the kinematic characteristics of different relay start techniques with the new starting block Omega OSB11. Eleven international youth swimmers were filmed during 1) no step with parallel feet, 2) no step with separated feet and 3) one-step starts and their centre of mass kinematics calculated with 2D-DLT algorithms. Results indicate that differences between techniques were detected in the spatiotemporal parameters of the block and aerial start phases (e.g., initial and take-off positions, entry height, preparation and changeover times) and in selected parameters of the underwater phase (e.g., emersion time and distance, underwater time and distance). However, no statistical effects were found in 5 m, 10 m and 15 m start times, nor in horizontal take-off velocity, despite an observed trend for the one-step start to be superior to the non-step techniques. These results suggest that differences between relay techniques could rely more on the swimmer’s body posture (angular kinematics) on the block, flight and underwater phases than on the centre of mass linear kinematics.

An Empirical Comparison of Encoding Algorithms of the Low Density Parity Check Code for Decode and Forward Protocol Relay System

Decode and a forward (DF) protocol relay technique in cooperative communication is becoming a more attractive method to achieve a higher throughput requirement for wireless communication these days. But the high complexity operation is a major issue in the DF protocol relay processing system. The encoding operation which is a pre-processing stage of the decoding process consumes high complexity in the DF protocol relay system. Thus, it is important to tackle the encoding operation to ensure low complexity and good performance of the subsequent decoding operation in the DF protocol relay system. Thus far, very limited works have been reported on identifying a suitable encoding algorithm of encoding operation for the DF protocol relay system using the Low Density Parity Check (LDPC) code. In this paper, we present a suitable encoding algorithm for the DF protocol relay system using the LDPC code. To find out the most suitable encoding algorithm for the DF protocol relay system using LDPC code, we introduce the LDPC code encoding model. Eight different encoding algorithms based on Lower Upper and Orthogonal Upper algorithms presented in the LDPC code encoding model. The encoding execution time, the number of nonzero, and the pattern of nonzero was used to evaluate the computational complexity performance of the designed LDPC code encoding model. The most suitable encoding algorithm for the required criteria of the DF protocol relay system using the LDPC code is identified.

UAV communications with millimeter-wave beamforming: Potentials, scenarios, and challenges

Unmanned aerial vehicle (UAV) has been widely used in many fields and is arousing global attention. As the resolution of the equipped sensors in the UAV becomes higher and the tasks become more complicated, much higher data rate and longer communication range are required in the foreseeable future. As the millimeter-wave (mmWave) band can provide more abundant frequency resources than the microwave band, much higher achievable rate can be guaranteed to support UAV services such as video surveillance, hotspot coverage, and emergency communications, etc. The flexible mmWave beamforming can be used to overcome the high path loss caused by the long propagation distance. In this paper, we study three typical application scenarios for mmWave-UAV communications, namely communication terminal, access point, and backbone link. We present several key enabling techniques for UAV communications, including beam tracking, multi-beam forming, joint Tx/Rx beam alignment, and full-duplex relay techniques. We show the coupling relation between mmWave beamforming and UAV positioning for mmWave-UAV communications. Lastly, we summarize the challenges and research directions of mmWave-UAV communications in detail.

Geographic information-based Data Transmission and Cooperative Communication for Vehicular Networks

With the advancements in Vehicular communication technologies in automobile engineering leads to enhancement of modern societies by utilizing Internet based data communication in a vehicular network to effectively avoid accidents and traffic congestions using Multi Input Multi Output (MIMO) cooperative relay technique for enhancing the aspects of performance by reduction of transmission energy consumption by taking the advantage of spatial and temporal diversity gain in a vehicular network as the conventional routing based on topology is merely not suitable over a dynamic vehicular network environment as GPS is used to identify effective route [4].In this paper we propose applications of cooperative communication techniques and their survey for identifying close relationship between forwarding and addressing techniques in a vehicular network and further we compare performance and energy consumption of cooperative techniques with the traditional multi-hop technique over Rayleigh channel using MQAM for optimization.

Geographic information-based Data Transmission and Cooperative Communication for Vehicular Networks

With the advancements in Vehicular communication technologies in automobile engineering leads to enhancement of modern societies by utilizing Internet based data communication in a vehicular network to effectively avoid accidents and traffic congestions using Multi Input Multi Output (MIMO) cooperative relay technique for enhancing the aspects of performance by reduction of transmission energy consumption by taking the advantage of spatial and temporal diversity gain in a vehicular network as the conventional routing based on topology is merely not suitable over a dynamic vehicular network environment as GPS is used to identify effective route [4].In this paper we propose applications of cooperative communication techniques and their survey for identifying close relationship between forwarding and addressing techniques in a vehicular network and further we compare performance and energy consumption of cooperative techniques with the traditional multi-hop technique over Rayleigh channel using MQAM for optimization.

Energy-efficiency maximization bidirectional direct and relay transmission

Energy-efficient transmission (EET) has become a very important problem in wireless communication. Optimal power allocation (OPA) is one of the general methods to achieve EET. But when OPA is only considered in EET, it maybe cannot analyze EET problems accurately. This paper aims at analyzing energy-efficient bidirectional direct and relay transmission (RT) through joint optimization of transmit power (TP) and transmit time (TT) allocation. In RT, direct links (DLs) are existed. The EET problems are given with three optimization cases: (i) maximizing sum throughput (ST) to maximize energy efficiency (EE), in such case, optimal TT (OTT), optimal relay position (ORP), and outage probability analysis are given; (ii) minimizing total energy consumption (TEC) to maximize EE, in such case, optimal TP (OTP), OTT with gradient-descent algorithm, and influences of asymmetry and asymmetry transmission tasks are given; and (iii) maximizing ST and minimizing TEC simultaneously to maximize EE, in such case, Dinkelbach’s algorithm and one-by-one optimal algorithm are given. Simulation results are presented to validate theoretical analysis. Results reveal that relay technique and DLs in RT can improve system’s EE.