Reconfigurable Intelligent Surface (RIS)-assisted OFDM millimeter-wave communication is pivotal for achieving high spectral efficiency and wide coverage in 6G. Nonetheles, the inherent peak-to-average power ratio (PAPR) issue of OFDM persists. Considering the high computational complexity and poor adaptability to RIS hardware of conventional PAPR reduction algorithms, we propose a novel PAPR reduction method based on hierarchical codebooks (HC). First, leveraging the HC structure in RIS beam training, a PAPR-aware hierarchical phase-perturbation codebook has been designed. Then, based on this codebook, both the classical selective mapping (SLM) and partial transmission sequence (PTS) algorithms were enhanced, resulting in two low-overhead, hardware-friendly PAPR reduction schemes: HC-SLM and HC-PTS. Simulation results demonstrate that under typical system configurations, the proposed algorithm reduces computational complexity by approximately 50%-70% and decreases sideband information overhead to less than one-quarter of that achieved by conventional methods. Furthermore, under various modulation schemes and typical signal-to-noise ratio (SNR) conditions, when the complementary cumulative distribution function (CCDF) is 10(-3), the PAPR can be reduced by 0.1-0.5 dB. This performance, achieved with low computational complexity, approaches and even partially surpasses that of conventional exhaustive search methods with significantly higher computational overhead. This provides an effective solution for the low-power, high-efficiency practical deployment of RIS-OFDM systems.

Intelligent Reflecting Surface (IRS) technology is a promising solution for improving signal propagation in B5G and 6G wireless communication systems. However, a significant challenge is their inherently high Peak-to-Average Power Ratio (PAPR), leading to inefficiencies in power amplifiers and increased signal distortion. We propose a two-stage approach to jointly reduce the PAPR named PA-IPTS algorithm. The initial stage employs a suboptimal iterative partial transmission sequence (IPTS) algorithm to reduce the PAPR of OFDM signals at the transmitter. In the second stage, we introduce the phase adjustment(PA) technique. The phase of the IRS reflection units is adjusted via the gradient descent method to further reduce the PAPR. Simulation results indicate that the PAPR of the proposed scheme can be reduced by approximately 5.2 dB and 5.8 dB at CCDF $10^{-3}$ for 16-QAM and 32-QAM signals, respectively. Consequently, the proposed algorithm emerges as an effective, low-complexity PAPR suppression in IRS-assisted OFDM systems.

课程教学案例库是培养学生能力的重要载体,针对目前课程案例库建设中存在的问题,从案例资源库构建、在线数字化平台设计、评价和保障监督体系完善等方面,探索了基于“互联网+”的无线通信原理课程案例库建设途径.

新高考志愿设置由"学校优先"变为"专业优先",因此高校在招生过程中,专业教师参与招生宣传和咨询工作变得尤为重要.文章阐述了新高考背景下高校招生宣传工作遇到的挑战,以中国石油大学(华东)专业教师在招生宣传工作中的实践为例,介绍新高考背景下发挥教师专业优势,突出专业特色宣传,充分利用新媒体,采用线上线下结合等多种形式,从而推动新高考背景下高校招生工作的顺利进行,实现考生与专业的最佳双向匹配.

改革传统数字逻辑电路实验教学模式,探索融合CDIO先进的工程教育理念,以"简易数字跑表"实验为例,从项目内容、项目要求到项目评价三个角度介绍了新的实验教学方法,使学生在"构思—设计—实现—运作"四个阶段较好地发挥主观能动性,在对整体知识结构的掌握、单一知识点的理解、工程实践能力的训练、团队协作意识的提高各个方面,均取得明显的效果.

结合电路实例,分析组合逻辑电路产生竞争-冒险现象的原因,并采用修改逻辑设计和引入滤波电容两种常用方法消除竞争-冒险现象.利用Multisim仿真软件中的虚拟元件搭建电路图,仿真结果直观清晰展示了竞争-冒险现象产生的时刻和消除电路的作用.

大学生科研能力的训练与提高是培养创新型人才的基本保障.目前我国高校大学生科研能力整体水平尚低,基本科研素质不高,部分教师责任感不强,学生科研组织管理形式化.针对这种现状,提出"三个专业化"的培养模式,即组织管理专业化、指导队伍专业化、科研训练专业化.

分析了数字逻辑电路课程教学中存在的问题,提出基于CDIO工程实践理念的贯穿式教学新模式,经过对教学内容的设计与实践,激发了学生的学习兴趣,帮助学生对数字逻辑电路课程内容建立了前后关联的整体认识,培养了学生的工程实践能力和团队协作意识.

在C语言程序设计课程的教学实践环节中,引入计算机模拟案例是培养学生计算思维能力的有效手段之一.文章从蒙特卡罗算法思想入手,针对蒲丰投针问题引出3种计算π的统计学方法,有针对性地讨论计算机随机数和模拟多种分布的随机事件,以培养学生的计算思维能力.

增益修改的卡尔曼滤波(MGEKF)算法在实际应用时,一般使用带有误差的测量值代替真实值进行增益修正计算,导致修正结果也被误差污染.针对这一问题,提出一种基于反向传播神经网络(BPNN)改进的MGEKF算法,该算法使用训练后的神经网络代替MGEKF的增益修正函数.该算法在网络训练阶段,以实际测量值作为神经网络的输入,真实值修正后的结果作为训练目标;在实际应用中,使用网络的输出修正卡尔曼增益.针对移动单站只测向目标定位问题进行了实验,实验结果表明:该算法与扩展卡尔曼滤波(EKF)、MGEKF、平滑增益修改的卡尔曼滤波(sMGEKF)算法相比:定位精度至少提升10％,并且有更强的稳定性.

In order to solve the problem of low bandwidth utilization while the peak-to-average power ratio(PAPR) is reduced in visible light communication-orthogonal frequency division multiplexing (VLC-OFDM) system. In this paper a novel method of combining ScaledPTS and Clipping algorithm to decrease the PAPR is proposed, and this scheme needn't transmit the side information(SI). The results show that the proposed method improves the bandwidth utilization and ensures the PAPR reduction performance.

针对计算机专业毕业生特长不突出、动手能力欠缺的现状以及现有计算机专业实践教学体系中存在的问题,提出集中—分散相结合的实践教学模式,以软件开发方向为例,说明如何构建跨年级贯通式实践教学体系,如何制定集中—分散相结合的一体化考核及协同评价机制.

广播是无线多跳网络的基本操作,针对现有广播算法大多存在转发冗余度高、广播开销大的问题,提出一种分段式扩展环搜索算法S-ERS.该算法从数据分组中提取距离信息,在此基础上将广播分解为两个阶段:首先寻找靠近目标的节点;然后以它为源点重启新的扩展环搜索过程.S-ERS算法使搜索限定在目标最可能出现的区域,以减少搜索的盲目性,降低广播开销.理论分析和仿真结果表明,S-ERS算法在多种场景下比传统扩展环算法的开销小,最好情况下能降低约50％.

计算思维是融合数学思维和工程思维的重要科学思维,代表着一种普遍的态度和一类普适的技能,而大学计算机基础教学是培养学生计算思维能力的重要载体.文章基于多年大学计算机基础和程序设计课程教学工作的经验体会,结合对计算思维的认知和实践,提出计算思维驱动C语言程序设计课程教学改革的思路和建议.

Cooperative downloading is an important measure for increasing the amount of data downloaded to the users of Vehicular Networking (VANET). However, data exchange causes frequent collision among cooperative vehicles and the client. To solve the problem, in this paper, we propose a transmission scheduling method. Firstly, the method builds a k-constraint routing tree according to the amount of linked route, and then schedules the time to transmit for every node in the tree. The goal of the method is to forward data as soon as possible on the premise of collision free. Simulation results indicate the benefits of the proposed scheme in terms of increasing efficiency and reducing delay.

PTS(Partial transmit sequence) is a valid and distortionless technique used to reduce the PAPR(peak-to-average power ratio) in OFDM(orthogonal frequency division multiplexing)system. However, this algorithm has a high computational complexity. In this paper, to balance the performance and the computation complexity, we describe a simplified scheme for finding the best scrambling sequences based on hamming-tabu-search to achieve the reduction of computational complexity. Algorithm analysis and simulation results show that, as compared with PTS method, the proposed scheme could be implemented with lower complexity while at no loss of PAPR performance.

In the audio encoder of Surveillance Video and Audio Coding (SVAC), both audio signals and MEL-frequency cepstral coefficients (MFCCs) are coded and this leads to high computational complexity. This paper proposes a novel scheme for SVAC in which speech coding module based on Algebraic Code Excited Linear Prediction (ACELP) is removed completely and speech waveforms can be reconstructed from MFCCs in decoding. The novel scheme greatly simplifies the structure of SVAC and also has a high performance for decoded speech signals in quality evaluation.

ABSTRACTThe ever growing dependence on the Internet makes people keen on accessing the network anytime and anywhere, even while driving cars. Cooperative downloading among vehicles could help the clients obtain more data when running out of access point coverage area. One of the methods is that the access point predicts communication duration between the helper and the client according to the registered speed of vehicles to decide how many packets should be carried by the helper. However, it is possible that cooperative vehicles cannot always transmit all of the carried data to the client due to the changing speed. A key challenge that lies at the heart of this problem is how to increase the packet transmitting rate of cooperative vehicles. Towards the end, this paper proposes a novel compensation model that exploits nodes own regulatory function to mitigate the packet transmission loss. By analysing a real speed dataset collected from a test car with global positioning system running from May 2011 to July 2012 on the No. G15 highway in China, we derive a strong spatiotemporal regularity in vehicle speeds. Impending speed can be predicted, therefore, using Markov chain. On the basis of the aforementioned quantitative prediction, the compensation schemes is presented to increase received data amount by using the characteristics of encountering, overtaking and being overtaken among vehicles. Simulation results indicate the benefits of the proposed model in terms of increasing throughput and reducing delay. Copyright © 2013 John Wiley & Sons, Ltd.

Partial transmit sequence (PTS) is a distortionless technique used to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. However, it has a relatively high computational complexity. A simplified scheme is proposed in this paper. In the proposed scheme, the computation for finding the best scrambling sequences is simplified by making use of the tabu search algorithm, thus achieving the reduction of computational complexity. Algorithm analysis and simulation results show that, as compared with conventional method, the proposed scheme could be implemented with lower complexity while at no loss of PAPR performance.

The technique is a kind of new concept of anti rolling ship at zero forward speed. It is different from conventional ship fin stabilizer that the lift of fin stabilizer based on movement mode of pitching and heaving is produced by initiative swing at zero speed. The lift control system is built according to lift feedback and lift limit. It is undoubtedly another development to introduce lift control to ship roll stabilization at zero forward speed. The simulation of anti rolling effect is researched at the different sea wave condition about significant wave height is 1 m and 2 m, wave direction angle is 90 . And the anti rolling effects are 78.30% and 56.92%respectively. It is proved that the designed system could be satisfied with the need of anti rolling ship at zero speed. This research is supported by the science and technology research project of Education Department of Heilongjiang Province (11544044).