Power Splitting Based SWIPT in Network-Coded Two-Way Networks with Data Rate Fairness:An Information-Theoretic Perspective

This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting(EH) relay. We present a power splitting(PS)-based two-way relaying(PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signalto-noise ratio(SNR), the performance loss is relatively small. Another observation is that, in relatively high SNR regime, PS-TWR outperforms time switching-based two-way relaying(TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.

Performance analysis of a class of networked control systems under data rate constraints

In networked control system (NCS) where control loop is closed over communication network, limited data rate may deteriorate control performance even destabilize the control system. In this paper, performance analysis of a typical second-order control system with data rate constraints is conducted, and the concept of critical data rate (CDR) is presented. In order to find the CDR in NCS, an approximate searching method is proposed to guarantee acceptable control performance.

Maximum Data Generation Rate Routing Protocol Based on Data Flow Controlling Technology for Rechargeable Wireless Sensor Networks

For rechargeable wireless sensor networks,limited energy storage capacity,dynamic energy supply,low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanently from a source to destination in a distributed scenario.Therefore,before data delivery,a sensor has to update its waking schedule continuously and share them to its neighbors,which lead to high energy expenditure for reestablishing path links frequently and low efficiency of energy utilization for collecting packets.In this work,we propose the maximum data generation rate routing protocol based on data flow controlling technology.For a sensor,it does not share its waking schedule to its neighbors and cache any waking schedules of other sensors.Hence,the energy consumption for time synchronization,location information and waking schedule shared will be reduced significantly.The saving energy can be used for improving data collection rate.Simulation shows our scheme is efficient to improve packets generation rate in rechargeable wireless sensor networks.

A new method for improving the inductively coupled data transmission rate of mooring buoy based on carrier signal frequency selection

In the inductively coupled data transmission system of the mooring buoy, the carrier signal frequency of the transmission channel is limited due to the inherent characteristics of the system, resulting in limited channel bandwidth. The limited channel bandwidth limits the increase in inductively coupled data transmission rate.In order to improve the inductively coupled data transmission rate of mooring buoy as much as possible without damaging the data transmission performance, a new method was proposed in this paper. The method is proposed to improve the data transmission rate by selecting the appropriate carrier signal frequencies based on the principle of maximizing the amplitude value of amplitude-frequency characteristic curve of the system. Research has been done according to this method as follows. Firstly, according to the inductively coupled transmission mooring buoy structure, the inductively coupled data transmission circuit model was established. The binary frequency shift keying(2FSK) digital signal modulation mode was selected. Through theoretical analysis, the relation between the carrier signal frequency and the data transmission performance, the relation between the carrier signal frequency and the 2FSK signal bandwidth were obtained. Secondly, the performance and the bandwidth of the signal transmission were studied for the inherent characteristics of the actual inductively coupled data transmission system. The amplitude-frequency characteristic of the system was analyzed by experiments. By selecting the appropriate carrier signal frequency parameters, an excellent data transmission performance was guaranteed and a large 2FSK signal bandwidth was obtained. Finally, an inductively coupled data transmission rate optimization experiment and a bit error rate analysis experiment were designed and carried out. The results show that the high-speed and reliable data transmission of the system was realized and the rate can reach 100 kbps.

Enhanced Data Transmission Rate of XCTD Profiler Based on OFDM

An expendable conductivity-temperature-depth profiler(XCTD)is one of the most important instruments used to obtain hydrological data,such as temperature and conductivity,and detect ocean depth in a large area.However,the XCTD channel provides poor time-varying performance,narrowband,and low signal-to-noise ratio(SNR),which severely restricts the data transmission rate.In contrast to conventional single-carrier modulation techniques,such as amplitude-shift keying and differential phase-shift keying,this article provides a new method,based on orthogonal frequency division multiplexing(OFDM)to enhance the data transmission rate of deep-sea abandoned profilers.We apply the OFDM to enhance the SNR of the XCTD,which is achieved by reducing the data transmission rate of each sub-channel.Moreover,the bandwidth utilization may be improved by increasing the number of subcarriers in a given bandwidth,which enhances the data transmission rate.Based on analysis of the XCTD channel model,OFDM with different parameters such as constellation mapping,number of subcarriers,subcarrier spacing,signal period and cyclic prefix are achieved.To verify the effectiveness of the OFDM,this study investigates the influence of different parameters on the data transmission rate at different noise levels,i.e.,-20 dB and-40 d B.

Fast Rate Fault Detection Filter for Multirate Sampled-data Systems

This paper focuses on the fast rate fault detection filter (FDF) problem for a class of multirate sampled-data (MSD) systems. A lifting technique is used to convert such an MSD system into a linear time-invariant discrete-time one and an unknown input observer (UIO) is considered as FDF to generate residual. The design of FDF is formulated as an H∞ optimization problem and a solvable condition as well as an optimal solution are derived. The causality of the residual generator can be guaranteed so that the fast rate residual can be implemented via inverse lifting. A numerical example is included to demonstrate the feasibility of the obtained results.

Making Data-Driven Transportation Decisions for Freight Operations

Using Louisiana’s Interstate system, this paper aims to demonstrate how data can be used to evaluate freight movement reliability, economy, and safety of truck freight operations to improve decision-making. Data mainly from the National Performance Management Research Data Set (NPMRDS) and the Louisiana Crash Database were used to analyze Truck Travel Time Reliability Index, commercial vehicle User Delay Costs, and commercial vehicle safety. The results indicate that while Louisiana’s Interstate system remained reliable over the years, some segments were found to be unreliable, which were annually less than 12% of the state’s Interstate system mileage. The User Delay Costs by commercial vehicles on these unreliable segments were, on average, 65.45% of the User Delay Cost by all vehicles on the Interstate highway system between 2016 and 2019, 53.10% between 2020 and 2021, and 70.36% in 2022, which are considerably high. These disproportionate ratios indicate the economic impact of the unreliability of the Interstate system on commercial vehicle operations. Additionally, though the annual crash frequencies remained relatively constant, an increasing proportion of commercial vehicles are involved in crashes, with segments (mileposts) that have high crash frequencies seeming to correspond with locations with recurring congestion on the Interstate highway system. The study highlights the potential of using data to identify areas that need improvement in transportation systems to support better decision-making.

非结构化高维大数据异常流量时间点挖掘算法

非结构化数据的维度较高,每个样本数据包含的特征非常多,导致了维度灾难问题,使得降低维度并保持有效特征提取难度较大,影响大数据流量异常时间点挖掘的精度。为此,提出新的基于空间映射的非结构化高维大数据流量异常时间点挖掘方法。通过近似解集的几何特征建立稀疏回归模型,求解高维目标空间映射到低维目标子空间的稀疏投影矩阵。根据密度分布选择出一个高密度集合作为聚类中心的候选集,确定聚类的初始聚类中心。同时对聚类形成的各个簇采用剪枝算法,选择时间点候选集,对候选集展开二次判断,挖掘高维大数据流量异常时间点。实验结果表明,数据的降维能有效提高流量异常挖掘精度。相比之下,所提方法的高维大数据流量异常时间点挖掘更加精准,耗时更短。

基于环境中移动运输代理的传感器网络建模

针对大型稀疏传感器网络中的数据获取,本文提出了一种利用环境中普遍存在的移动代理来连接稀疏传感器的网络体系结构和一种2-维网格随机游走分析模型;提出的传感器网络模型由3个抽象层构成,即由无线传感器构成的底层、由各种运输代理构成的中间层和由接入点/中央存储库构成的顶层。具体实现原理是位于中间层的移动运输代理从底层分布的无线传感器收集数据并缓冲数据,然后经过游走运输,最后将从底层的无线传感器收集的数据交付到顶层必要的接入点进行必要的存储和处理,从而实现整个传感器网络的数据获取;理论分析和仿真实验结果表明,提出的基于移动运输代理的传感器网络模型不仅具有较好的鲁棒性和可扩展性,而且相比于基站网络模型和Ad-hoc网络模型,在传感器功率消耗、数据成功率和基础设施投入成本方面有明显的优势。

双极化复用信号的接收技术研究

针对双极化复用传输系统的交叉极化干扰问题,提出一种适用于双极化复用信号的接收技术。在接收链路本振不同源的情况下,参考信号与干扰信号载波频率不同,干扰不能被对消。从理论上推导了参考信号与干扰信号之间的频率关系,并通过频率补偿模块消除参考信号与干扰信号间的频差,使得参考信号与干扰信号频率一致,从而实现极化干扰对消。测试结果表明,链路本振不同源的情况下,该方法可有效减少交叉极化干扰带来的误码率恶化。

短视频消费时长能够反映就业率吗?

鉴于现行就业统计方式不能及时、准确反映经济运行形势,如何利用大数据对现有统计指标进行补充成为一个重要问题。鉴于短视频消费已经成为当今社会主要的休闲娱乐方式,文章将短视频消费纳入效用函数,通过失业人员与雇员在时间分配上的差异,揭示全社会用于观看短视频的时间与就业率之间存在的理论联系。通过计量分析,研究发现基于抖音在线人数计算的估计值与描述失业者寻找工作行为的百度搜索指数呈现正相关关系,可以借助短视频观看时长变动说明失业者寻找工作行为的变化。基于抖音在线人数估计的劳动参与率与16—24岁城镇调查失业率存在显著负相关关系,两者的皮尔逊相关系数为-0.862,因此估计的劳动参与率可以作为城镇调查失业率,特别是16—24岁劳动力调查失业率的补充。

基于IGWO算法的WSNs能耗均衡路由

能源限制是无线传感器网络(wireless sensor networks,WSNs)面临的一系列挑战中的首要问题。如何有效管理和利用有限的能量是设计WSNs路由协议的关键。为此,提出基于改进的灰狼优化算法的WSNs能耗均衡路由(improved grey wolf optimizer based energy balancing secure,IGWOEBS)算法,能快速搜索并建立从源节点至汇聚节点的路径,提高数据包传递率,均衡节点能耗。仿真结果表明,相比于动态分区路由算法和多策略灰狼算法,该算法延长了网络生命周期,并提升了数据收集发送传输率。

A Software Reliability Model for OSS Including Various Fault Data Based on Proportional Hazard-Rate Model

The software reliability model is the stochastic model to measure the software reliability quantitatively. A Hazard-Rate Model is the well-known one as the typical software reliability model. We propose Hazard-Rate Models Considering Fault Severity Levels (CFSL) for Open Source Software (OSS). The purpose of this research is to make the Hazard-Rate Model considering CFSL adapt to baseline hazard function and 2 kinds of faults data in Bug Tracking System (BTS), i.e., we use the covariate vectors in Cox proportional Hazard-Rate Model. Also, we show the numerical examples by evaluating the performance of our proposed model. As the result, we compare the performance of our model with the Hazard-Rate Model CFSL.

An Interconnection between Elevated SCC Levels in Milk around the First Artificial Insemination and Pregnancy Rate in Dairy Cows

The aim of this study was to evaluate the impact of the somatic cell count (SCC) levels measured at 28-test-day intervals or pregnancy rate at the first artificial insemination of Holstein Friesian cows. All necessary information was taken from test day and farm records. Levels of SCC in milk, 30 days before, and 30 days after the first artificial insemination (FAI) date were divided into 4 categories and their interconnection with pregnancy rate (PR) at FAI was evaluated by applying logistic models. A SCC threshold of 150.000 cells/ml of milk was used to differentiate uninfected udders and infected udders of Holstein Friesian cows. A level of SCC > 150.000 cells/ml in milk, and a level of SCC < 150.000 cells/ml before and after FAI respectively were considered udders with new infections. A level of SCC > 150.000 cells/ml in milk before FAI as well as after FAI, was considered chronically infected udders or subclinical intramammary infections (IMI). Data from 792 FAIs from farm and test day records over a 4-year period (2019-2022) were evaluated. The outcome of this study revealed that the risk for low PR at the first AI was increased in cows with infected udders (OR = 1.33, CI 0.99 - 1.78), compared with uninfected udders. Increased levels of SCC after FAI had a negative effect on PR, while before FAI was not affected. To achieve a good PR, mastitis control measures must be fully adopted to a large extent around the first AI.

一种宽带非线性信道校正方法

针对高速数传解调器接收宽带高阶调制信号时因信道非线性导致的性能恶化问题,提出一种基于两层自适应均衡网络的非线性信道校正方法。该方法先利用递归最小二乘法获得Volterra非线性前置校正系数,再利用自适应基带均衡器消除信道的剩余影响,以提升解调器的捕获跟踪能力,并在高速数传解调器工程应用中实现2.4 Gb/s 16QAM信号的稳定接收。

基于网络开放数据的区域消防救援总体有效覆盖率评估

高效准确地掌握消防救援有效覆盖率是优化消防站点资源配置的前提。将判断是否有效覆盖的消防救援行程时间阈值定为240 s,建立了基于时间加权的区域消防救援总体有效覆盖率评估模型。基于网络开放数据收集了长沙的50座消防站作为消防救援供给点、5746家被抽查到的社会单位作为消防救援需求点,并调用网络地图应用程序编程接口基于实时路况来仿真消防救援行程时间。在连续7 d内设置197个评估场景,共获得了1131962个有效样本,进而得出:长沙消防救援总体有效覆盖率为21.22%,结果等级为“C”,消防救援水平一般,需加强消防站建设。这种基于网络开放数据的区域消防救援有效覆盖率评估,具备高效和准确的特点,可为优化消防站点资源配置、提升公共安全水平提供关键理论和方法支撑。

基于运营数据的发动机压气机叶片裂纹扩展规律研究

为研究航空发动机实际服役中转子叶片在复杂载荷作用下的裂纹损伤扩展规律,基于航空发动机运营数据构建叶片的裂纹扩展寿命曲线,同时采用断裂力学理论建立裂纹扩展速率公式。以高压压气机叶片为实例,通过流固耦合方法构建压气机叶片结构的载荷模型,分别采用Paris、Walker、Newman裂纹扩展速率公式对压气机叶尖区域进行三维裂纹扩展分析。仿真结果表明,三种裂纹扩展速率公式在裂纹扩展前期预测结果与发动机运营数据裂纹扩展曲线具有一致性,可较好地描述叶片裂纹扩展规律;在裂纹稳定扩展阶段,Walker和Newman公式预测结果相对危险,Paris公式预测结果吻合度较高,并且能与厂家技术手册中关于其损伤发展控制要求相互印证。

基于资源感知的分布式爬虫任务调度方法

文中致力于开发一种基于资源感知的分布式爬虫任务调度方法,以优化分布式环境中各节点的系统资源利用,提升爬虫任务的执行效率。该方法通过引入资源感知调度算法和节点优先级管理,实现对节点中CPU、内存、网络等资源的监测,以便均衡调度爬虫任务,即确保爬虫任务在资源利用率较低的节点上执行,从而有效减轻各个节点之间资源过度占用和不均衡问题。另外,该方法引入的Flask提高了可扩展性,实现了可视化爬虫监控平台。实验结果表明,文中提出的方法在提高爬虫任务执行效率和适应性方面取得了显著效果,为分布式爬虫系统的进一步优化提供了有益指导。

基于图卷积网络和图数据增强技术的节点分类研究

在图卷积网络中,节点分类是一个基本问题,它涉及到图中节点的标签预测。然而,由于真实世界中的图往往具有复杂的结构和噪声,节点分类准确率往往不尽如人意。为了解决这个问题,提出了一种使用图神经网络和图数据增强技术的方法来提高节点分类准确率。首先,我们使用图数据增强技术对图数据进行预处理,对原始训练数据进行变换和扩展来生成更多训练样本,以此来提高模型的泛化性和鲁棒性,然后用图卷积网络模型对图数据进行节点分类,最后,在Cora数据集上进行了多次对比实验。实验结果表明,使用图卷积网络和图数据增强技术可以显著提高节点分类准确率,Cora数据集上的节点分类准确率从82.6%提高到了84.0%。

面向高性能众核处理器的超频DDR4访存结构设计

从高性能众核处理器的多路DDR4嵌入式工程应用出发,设计一种高密度DDR4串推互连结构,提出一种基于不同激励码型的仿真分析方法。采用双面盲孔印制板工艺折叠串推访存结构设计,解决地址组信号概率性出错问题。在压力测试环境下实测读/写信号波形良好,支持信号超频可靠传输,标称2666 Mbps的DDR4存储颗粒可以在3000 Mbps速率下长时间稳定运行。已在神威E级原型机等多台套大型计算装备研发中得到规模化推广应用,产生了良好的技术效益。