Channel assignment and power allocation for throughput improvement with PPO in B5G heterogeneous edge networks

In Beyond the Fifth Generation(B5G)heterogeneous edge networks,numerous users are multiplexed on a channel or served on the same frequency resource block,in which case the transmitter applies coding and the receiver uses interference cancellation.Unfortunately,uncoordinated radio resource allocation can reduce system throughput and lead to user inequity,for this reason,in this paper,channel allocation and power allocation problems are formulated to maximize the system sum rate and minimum user achievable rate.Since the construction model is non-convex and the response variables are high-dimensional,a distributed Deep Reinforcement Learning(DRL)framework called distributed Proximal Policy Optimization(PPO)is proposed to allocate or assign resources.Specifically,several simulated agents are trained in a heterogeneous environment to find robust behaviors that perform well in channel assignment and power allocation.Moreover,agents in the collection stage slow down,which hinders the learning of other agents.Therefore,a preemption strategy is further proposed in this paper to optimize the distributed PPO,form DP-PPO and successfully mitigate the straggler problem.The experimental results show that our mechanism named DP-PPO improves the performance over other DRL methods.

High throughput screening of single atomic catalysts with optimized local structures for the electrochemical oxygen reduction by machine learning

Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.

Energy Efficiency in ARQ-Based Multi-Hop Systems and the Tradeoff with Throughput

The minimum energy per bit(EPB)as the energy efficiency(EE)metric in an automatic retransmission request(ARQ)based multi-hop system is analyzed under power and throughput constraints.Two ARQ protocols including type-I(ARQ-I)and repetition redundancy(ARQ-RR)are considered and expressions for the optimal power allocation(PA)are obtained.Using the obtained optimal powers,the EE-throughput tradeoff(EETT)is analyzed and the EETT closed-form expressions for both ARQ protocols and in arbitrary average channel gain values are obtained.It is shown that how different throughput requirements,especially the high levels,affect the EE performance.Additionally,asymptotic analysis is made in the feasible high throughput values and lower and upper EETT bounds are derived for ARQ-I protocol.To evaluate the EE a distributed PA scenario,as a benchmark,is presented and the energy savinggain obtained from the optimal PA in comparison with the distributed PA for ARQ-I and ARQ-RR protocols is discussed in different throughput values and node locations.

Throughput Analysis of HARQ Scheme Based on Full-Duplex Two-Way AF SWIPT Relay

The simultaneous wireless information and power transfer(SWIPT)relay system is one of the emerging technologies.Xiaomi Corporation and Motorola Inc.recently launched indoor wireless power transfer equipment is one of the most promising applications.To tap the potential of the system,hybrid automatic repeat request(HARQ)is introduced into the SWIPT relay system.Firstly,the time slot structure of HARQ scheme based on full duplex two-way amplify and forward(AF)SWIPT relay is given,and its retransmission status is analyzed.Secondly,the equivalent signal-to-noise ratio and outage probability of various states are calculated by approximate simplification.Thirdly,the energy harvesting power in each state is calculated.Finally,the energy harvested-throughput sum function is constructed to characterize the performance of energy harvesting and data transmission.Simulation results show that the proposed HARQ scheme has better energy harvestedthroughput sum function than the traditional HARQ scheme.When P_(2)=22 dB,the maximum sum function is 54.86%(the proposed HARQ scheme)and 52.307%(the traditional HARQ scheme),respectively.

Design and Research of High-throughput Automation System for Food Testing Laboratory

In the process of food testing,human operation is an important variable affecting the experimental results.In order to reasonably avoid the influence of human subjective operation behavior on the accuracy of detection results,the laboratory information management system was used as the information platform to design a high-throughput laboratory automation pre-treatment system based on the deep integration of mechanical principles,visual analysis,high-speed conduction,intelligent storage and other technical systems.The experimental results showed that the system could shorten the sample circulation cycle,effectively improve the laboratory biosafety,and meet the requirements of high-throughput processing of samples.

High-Throughput Growth of Hexagonal Boron Nitride Film Using Porous-Structure Isolation Layer

Chemical vapor deposition is considered as the most hopeful method for the synthesis of large-area high-quality hexagonal boron nitride on the substrate of catalytic metal. However, the size the hexagonal boron nitride films are limited to the size of growth chamber, which indicates a lower production efficiency. In this paper, the utilization efficiency of growth chamber is highly improved by alternately stacking multiple pieces of Cu foils and carbon fiber surface felt with porous structure. Uniform and continuous hexagonal boron nitride films are prepared on Cu foils through chemical vapor deposition utilizing ammonia borane as the precursor. This work develops a simple and practicable method for high-throughput preparation of hexagonal boron nitride films, which could contribute to the industrial application of hexagonal boron nitride. .

Design of Raptor-Like LDPC Codes and High Throughput Decoder Towards 100 Gbit/s Throughput

This paper proposes a raptor-like low-density parity-check(RL-LDPC)code design together with the corresponding decoder hardware architecture aiming at next-generation mobile communication.A new kind of protograph different from the 5G new radio(NR)LDPC basic matrix is presented,and a code construction algorithm is proposed to improve the error-correcting performance.A multi-core layered decoder architecture that supports up to 100 Gbit/s throughput is designed based on the special protograph structure.

Throughput scheduling in cognitive radio networks based on immune optimization

To study the throughput scheduling problem under interference temperature in cognitive radio networks, an immune algorithm-based suboptimal method was proposed based on its NP-hard feature. The problem is modeled as a constrained optimization problem to maximize the total throughput of the secondary users（ SUs）. The mapping between the throughput scheduling problems and the immune algorithm is given. Suitable immune operators are designed such as binary antibody encoding, antibody initialization based on pre-knowledge, a proportional clone to its affinity and an adaptive mutation operator associated with the evolutionary generation. The simulation results showthat the proposed algorithm can obtain about 95% of the optimal throughput and operate with much lower liner computational complexity.

Analysis of throughput and stability for ACK-ALOHA-CDMA channel

A new acknowledgment-type slotted-ALOHA code division multiple access （ACK-ALOHA-CDMA） channel which can be used in the inbound channels of very small aperture terminal（VSAT） networks is proposed in order to simplify the synchronization equipment of networks in the slotted-ALOHA- CDMA systems. By dividing all VSAT stations into M subsystems and sending out periodic inquiry signals from the Hub station to the VSAT station, the channel model is established. By the means of deriving multi-access interference（MAI） and packet detecting probability, steady-state throughput is calculated. By applying diffusion process theory to the analysis of the stability of the ACK-ALOHA-CDMA channel, the drift parameter a（r）, the diffusion parameter b（r） and the steady transition probability density p （r） are investigated. Simulation results indicate that significant performance improvement and high-bandwidth efficiency can be gained and one or two steady equilibrium points can be obtained by using this channel. Consequently, the ACK- ALOHA-CDMA channel is very suitable for cutting down on the expense of satellite VSAT systems and distributed packet radio networks.

High-throughput research on superconductivity

As an essential component of the Materials Genome Initiative aiming to shorten the period of materials research and development, combinatorial synthesis and rapid characterization technologies have been playing a more and more important role in exploring new materials and comprehensively understanding materials properties. In this review, we discuss the advantages of high-throughput experimental techniques in researches on superconductors. The evolution of combinatorial thin-film technology and several high-speed screening devices are briefly introduced. We emphasize the necessity to develop new high-throughput research modes such as a combination of high-throughput techniques and conventional methods.

HIGH THROUGHPUT DRILLING OF TITANIUM ALLOYS

The experiments of high throughput drilling of Ti-6Al-4V at 183 m/min cutting speed and 156 mm^3/s material removal rate using a 4 mm diameter WC-Co spiral point drill are conducted. At this material removal rate, it took only 0.57 s to drill a hole in a 6.35 mm thick Ti plate. Supplying the cutting fluid via through-the-drill holes and the balance of cutting speed and feed have proven to be critical for drill life. An inverse heat transfer model is developed to predict the heat flux and the drill temperature distribution in drilling. A three-dimensional finite element modeling of drilling is con-ducted to predict the thrust force and torque. Experimental result demonstrates that, using proper machining process parameters, tool geometry, and fine-grained WC-Co tool material, the high throughput machining of Ti alloy is technically feasible.

High throughput RNA sequencing utility for diagnosis and prognosis in colon diseases

RNA sequencing is the use of hight hroughput next generation sequencing technology to survey, characterize, and quantify the transcriptome of a genome. RNA sequencing has been used to analyze the pathogenesis of several malignancies such melanoma, lung cancer, and colorectal cancer. RNA sequencing can identify differential expression of genes(DEG's), mutated genes, fusion genes, and gene isoforms in disease states. RNA sequencing has been used in the investigation of several colorectal diseases such as colorectal cancer, inflammatory bowel disease(ulcerative colitis and Crohn's disease), and irritable bowel syndrome.

Throughput Analysis of the IEEE 802.11 Distributed Coordination Function Considering Erroneous Channel and Capture Effects

This paper presents a performance study of the distributed coordination function （DCF） of 802.11 networks considering erroneous channel and capture effects under non-saturated traffic conditions employing a basic access method.The aggregate throughput of a practical wireless local area network （WLAN） strongly depends on the channel conditions.In a real radio environment,the received signal power at the access point from a station is subjected to deterministic path loss,shadowing,and fast multipath fading.The binary exponential backoff （BEB） mechanism of IEEE 802.11 DCF severely suffers from more channel idle time under high bit error rate （BER）.To alleviate the low performance of IEEE 802.11 DCF,a new mechanism is introduced,which greatly outperforms the existing methods under a high BER.A multidimensional Markov chain model is used to characterize the behavior of DCF in order to account both non-ideal channel conditions and capture effects.

Channel Estimation and Throughput Evaluation for 5G Wireless Communication Systems in Various Scenarios on High Speed Railways

The fifth generation （5G） wireless communication is currently a hot research topic and wireless communication systems on high speed railways （HSR） are important applications of 5G technologies. Existing stud- ies about 5G wireless systems on high speed railways （HSR） often utilize ideal channel parameters and are usually based on simple scenarios. In this paper, we evaluate the down- link throughput of 5G HSR communication systems on three typical scenarios including urban, cutting and viaduct with three different channel estimators. The channel parameters of each scenario are generated with tapped delay line （TDL） models through ray-tracing sim- ulations, which can be considered as a good match to practical situations. The channel estimators including least square （LS）, linear minimum mean square error （LMMSE）, and our proposed historical information based ba- sis expansion model （HiBEM）. We analyze the performance of the HiBEM estimator in terms of mean square error （MSE） and evaluate the system throughputs with different channel estimates over each scenario. Simulation results are then provided to corroborate our proposed studies. It is shown that our HiBEM estimator outperforms other estimators and that the sys-tem throughput can reach the highest point in the viaduct scenario.

High Throughput Sequencing of circRNAs in Tomato Leaves Responding to Multiple Stresses of Drought and Heat

Our aim is to study the roles of a new emerging group of non-coding RNAs, circRNAs, in tomato(Solanum lycopersicum L.) plants grown at the combination of drought and heat, two of the most usual stress conditions known to frequently happen in field. Tomato seedlings from cultivar‘Jinling Meiyu’ were treated without stresses(control), at water shortage, high temperature and subjected the multiple stresses. In total, 467 circRNAs were identified with 87.82% from exon using high throughput sequencing technology. Among the circRNAs, 70 were from chr1 with the range from 23 to 49 from the other chromosomes. In detail, 156 circRNAs were shared in the four libraries, while 21, 17 and 36 circRNAs were only shown in drought, heat and multiple stresses libraries, respectively. Through a differential expression analysis, four, seven and nine circRNAs were differentially regulated in tomato at drought, heat and multiple stresses as compared with control. These circRNAs played roles on photosynthesis, starch and sucrose metabolism, RNA transport, RNA degradation, spliceosome, ribosome, etc. Our study underlined the potential role of circRNAs involved in the abiotic stress response in tomato, which might pave the way for studying biological roles of circRNAs responding to multiple stresses in plants.

Comparison of rumen archaeal diversity in adult and elderly yaks(Bos grunniens)using 16S rRNA gene high-throughput sequencing

This study was conducted to investigate the phylogenetic diversity of archaea in the rumen of adult and elderly yaks. Six domesticated female yaks, 3 adult yaks （（5.3±0.6） years old）, and 3 elderly yaks （（10.7±0.6） years old）, were used for the rumen contents collection. Illumina MiSeq high-throughput sequencing technology was applied to examine the archaeal composition of rumen contents. A total of 92 901 high-quality archaeal sequences were analyzed, and these were assigned to 2 033 operational taxonomic units （OTUs）. Among these, 974 OTUs were unique to adult yaks while 846 OTUs were unique to elderly yaks; 213 OTUs were shared by both groups. At the phylum level, more than 99% of the obtained OTUs belonged to the Euryarchaeota phylum. At the genus level, the archaea could be divided into 7 archaeal genera. The 7 genera （i.e., Methanobrevibacter, Methanobacterium, Methanosphaera, Thermogymnomonas, Methanomicrobiu, Meth- animicrococcus and the unclassified genus） were shared by all yaks, and their total abundance accounted for 99% of the rumen archaea. The most abundant archaea in elderly and adult yaks were Methanobrevibacterand Thermogymnomonas, respectively. The abundance of Methanobacteria （class）, Methanobacteriales （order）, Methanobacteriaceae （family）, and Methanobrevibacter （genus） in elderly yaks was significantly higher than in adult yaks. In contrast, the abundance of Ther-mogymnomonas in elderly yaks was 34% lower than in adult yaks, though the difference was not statistically significant. The difference in abundance of other archaea was not significant between the two groups. These results suggested that the structure of archaea in the rumen of yaks changed with age. This is the first study to compare the phytogenetic differences of rumen archaeal structure and composition using the yak model.

Microbial Diversity in Rhizosphere Soil of Cotinus coggygria Based on High Throughput Sequencing

In order to reveal the influence of different plant configurations on the microbial community structure and diversity in rhizosphere soil of Cotinus coggygria in Fragrant Hills park,the ITS+5.8S rDNA gene and 16S rDNA gene V3-V4 region sequencing analysis for fungi and bacteria,respectively,were conducted by high throughput sequencing(Illumina MiSeq).The results showed that the fungal diversity in the rhizosphere soil samples of C.coggygria in Fragrant Hills park in 2018 was significantly higher than that in 2016,and it was higher in the rhizosphere soil of healthy C.coggygria in Xunlupo than that in diseased ones in 2018.Verticillium dahliae,which is the causal agent of C.coggygria wilt,was detected in five soil samples.In 2018,the bacterial diversity in the rhizosphere soil of diseased C.coggygria in Xunlupo was the lowest,while it was the highest in the rhizosphere soil of healthy C.coggygria under Platycladus orientalis in Langfengting.

A low-power high-throughput link splitting router for NoCs

In this paper, we propose a technique for lowering the latency of the communication in a NoC （network on chip）. The technique, which can support two qualities of service （QoS）, i.e., the guaranteed throughput （GT） and best effort （BE）, is based on splitting a wider link into narrower links to increase throughput and decrease latency in the NoC. In addition, to ease the synchronization and reduce the crosstalk, we use the l-of-4 encoding for the smaller buses. The use of the encoding in the proposed NoC architecture considerably lowers the latency for both BE and GT packets. In addition, the bandwidth is increased while the power consumption of the links is reduced.

Delay-Throughput Tradeoff in Satellite Data Relay Networks with Prioritized User Satellites

The efficient antenna scheduling strategy for data relay satellites(DRSs)is essential to optimize the throughput or delay of the satellite data relay network.However,these two objectives conflict with each other since the user satellites(USs)with higher priorities take up more transmission time of DRSs’antennas for greater throughput but the USs storing more packets cause a severer waiting delay to the whole network.To balance the conflicting metrics for meeting the delay-throughput integrated requirements,we formulate the antenna scheduling as a stochastic non-convex fractional programming,which is challenging to be solved.For the tractability,we equivalently transform the fractional programming to a parametric problem and implement the Lyapunov drift to guarantee the constraint of mean rate stability.By proposing a delay and throughput tradeoff based antenna scheduling algorithm,we further transform the parametric problem to a solvable weight matching problem.Simulation results reveal the feasible region of the preference control parameter for integrated QoS cases and its variation relationship with network delay and throughput.

Impacts of Packet Collisions on Link Throughput in CSMA Wireless Networks

It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies on throughput analysis of CSMA wireless networks. However, for a typical CSMA network in which not all nodes can sense each other, it is still not well investigated how link throughputs are affected by collisions. We note that in practical 802.11-like networks, the time is divided into mini-timeslots and packet collisions are in fact unavoidable. Thus, it is desirable to move forward to explore how collisions in such a network will affect system performance. Based on the collision-free ideal CSMA network(ICN) model, this paper attempts to analyze link throughputs when taking the backoff collisions into account and examine the effect of collisions on link throughputs. Specifically, we propose an Extended Ideal CSMA Network(EICN) model to characterize the collision effects as well as the interactions and dependency among links in the network. Based on EICN, we could directly compute link throughputs and collision probabilities. Simulations show that the EICN model is of high accuracy. Under various network topologies and protocol parameter settings, the computation error of link throughputs using EICN is kept to 4% or below. Interestingly, we find that unlike expected, the effect of collisions on link throughputs in a modest CSMA wireless network is not significant, which enriches our understanding on practical CSMA wireless networks such as Wi-Fi.