期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
A novel dynamic step size LMS optimization scheme for interference reducing in FBMC-QAM
1
作者 DONG Qiyang MA Tianming +1 位作者 JIANG Xiaoxiao MA Honglei 《High Technology Letters》 EI CAS 2024年第3期290-296,共7页
Filter bank multicarrier quadrature amplitude modulation(FBMC-QAM)will encounter inter-ference and noise during the process of channel transmission.In order to suppress the interference in the communication system,cha... Filter bank multicarrier quadrature amplitude modulation(FBMC-QAM)will encounter inter-ference and noise during the process of channel transmission.In order to suppress the interference in the communication system,channel equalization is carried out at the receiver.Given that the con-ventional least mean square(LMS)equilibrium algorithm usually suffer from drawbacks such as the inability to converge quickly in large step sizes and poor stability in small step sizes when searching for optimal weights,in this paper,a design scheme for adaptive equalization with dynamic step size LMS optimization is proposed,which can further improve the convergence and error stability of the algorithm by calling the Sigmoid function and introducing three new parameters to control the range of step size values,adjust the steepness of step size,and reduce steady-state errors in small step sta-ges.Theoretical analysis and simulation results demonstrate that compared with the conventional LMS algorithm and the neural network-based residual deep neural network(Res-DNN)algorithm,the adopted dynamic step size LMS optimization scheme can not only obtain faster convergence speed,but also get smaller error values in the signal recovery process,thereby achieving better bit error rate(BER)performance. 展开更多
关键词 filter bank multicarrier quadrature amplitude modulation(FBMC-QAM) adap-tive equalization least mean square(LMS) dynamic step size
下载PDF
DQL-Based Intelligent Scheduling Algorithm for Automatic Driving in Massive MIMO V2I Scenarios 被引量:2
2
作者 Yong Liao Zisong Yin +1 位作者 Zhijing Yang Xuanfan Shen 《China Communications》 SCIE CSCD 2023年第3期18-26,共9页
Connected and autonomous vehicle(CAV)vehicle to infrastructure(V2I)scenarios have more stringent requirements on the communication rate,delay,and reliability of the Internet of vehicles(Io V).New radio vehicle to ever... Connected and autonomous vehicle(CAV)vehicle to infrastructure(V2I)scenarios have more stringent requirements on the communication rate,delay,and reliability of the Internet of vehicles(Io V).New radio vehicle to everything(NR-V2X)adopts link adaptation(LA)to improve the efficiency and reliability of road safety information transmission.In order to solve the problem that the existing LA scheduling algorithms cannot adapt to the Doppler shift and complex fast time-varying channel in V2I scenario,resulting in low reliability of information transmission,this paper proposes a deep Q-learning(DQL)-based massive multiple-input multiple-output(MIMO)LA scheduling algorithm for autonomous driving V2I scenario.The algorithm combines deep neural network(DNN)with Q-learning(QL)algorithm,which is used for joint scheduling of modulation and coding scheme(MCS)and space division multiplexing(SDM).The system simulation results show that the algorithm proposed in this paper can fully adapt to the different channel environment in the V2I scenario,and select the optimal MCS and SDM for the transmission of road safety information,thereby the accuracy of road safety information transmission is improved,collision accidents can be avoided,and bring a good autonomous driving experience. 展开更多
关键词 NR autonomous driving V2I link adap-tation massive MIMO deep Q-learning
下载PDF
放归普氏野马粪便含水量及颗粒大小的季节变化及性别差异 被引量:1
3
作者 张永军 胡德夫 +2 位作者 季荣 曹青 初红军 《干旱区地理》 CSCD 北大核心 2014年第2期259-264,共6页
粪便含水量(WC)和平均颗粒大小(MPS)反映了有蹄类动物体内水份平衡状况及咀嚼效率和消化率,是有蹄类动物在特定环境中生存对策的重要体现。放归普氏野马如何适应干旱环境,是重引入项目的重要研究内容。通过采集到卡拉麦里自然保护区内... 粪便含水量(WC)和平均颗粒大小(MPS)反映了有蹄类动物体内水份平衡状况及咀嚼效率和消化率,是有蹄类动物在特定环境中生存对策的重要体现。放归普氏野马如何适应干旱环境,是重引入项目的重要研究内容。通过采集到卡拉麦里自然保护区内春、夏、秋季共65份放归野马新鲜粪样,测定粪便含水量和粪便颗粒大小(湿筛法),并比较了这2个指标的季节和性别差异。结果表明:总体上,野马MPS在春季(3.98±0.08mm)显著高于夏季(3.65±0.05mm);春季头马MPS显著高于雌马(t=2.784,P=0.015),但夏、秋季两者无明显差异。春(73.17±1.05%)、夏(70.56±0.99%)、秋(68.12±0.79%)三季野马粪便WC依次降低,但差异不显著。头马的WC在春、夏、秋三季均高于雌马,在春季达极显著差异水平。研究表明:放归野马粪便MPS和WC的季节和性别差异,与环境中可用食物和水源优劣度及不同性别在家族群中承担的角色有关。 展开更多
关键词 粪便颗粒 粪便含水量 普氏野马 放归 适应
下载PDF
壁面函数在激波诱导分离流动中的应用 被引量:1
4
作者 胡偶 赵宁 刘剑明 《航空计算技术》 2013年第6期26-29,共4页
以数值模拟激波-附面层干扰引起的流动分离问题为研究背景,发展了基于有限体积方法的雷诺平均Navier-Stokes(RANS)方程的流场数值模拟方法。利用壁面函数模型得到壁面剪切应力,通过修正壁面粘性通量,构造了一种新的湍流边界处理方法,并... 以数值模拟激波-附面层干扰引起的流动分离问题为研究背景,发展了基于有限体积方法的雷诺平均Navier-Stokes(RANS)方程的流场数值模拟方法。利用壁面函数模型得到壁面剪切应力,通过修正壁面粘性通量,构造了一种新的湍流边界处理方法,并将其耦合到RANS方程和SST k-ω湍流模型的数值求解中;同时,针对激波诱导引起的附面层流动分离问题,提出一种附面层网格加密技术,能够自适应加密分离区内附面层网格,使得在流动分离区域也能够使用壁面函数模型。数值算例表明,壁面函数模型能够降低数值模拟结果对网格的依赖性;同时也验证了壁面函数耦合附面层网格自适应方法,在处理激波诱导引起的附面层流动分离问题时的有效性和准确性。 展开更多
关键词 激波-附面层干扰 分离流动 壁面函数 附面层网格加密 RANS SST k-ω湍流模型
下载PDF
网络流行语的社会心理语用分析 被引量:2
5
作者 辛丹 《齐齐哈尔师范高等专科学校学报》 2012年第1期66-67,共2页
网络流行语可以反映出网民的社会心理状况。通过对网络流行语的分析,总结出来其具有创新性、娱乐性、简洁性、不规范性、非本土性和隐含性。这些特性体现网民了社会心理的矛盾与统一体:宣泄与轻松的统一、跟风与反叛的统一、从简与含蓄... 网络流行语可以反映出网民的社会心理状况。通过对网络流行语的分析,总结出来其具有创新性、娱乐性、简洁性、不规范性、非本土性和隐含性。这些特性体现网民了社会心理的矛盾与统一体:宣泄与轻松的统一、跟风与反叛的统一、从简与含蓄的统一。此外,这些网络流行语的使用也体现了对交际语境的顺应。 展开更多
关键词 网络流行语 社会心理 顺应
下载PDF
论明清以来壮族种植结构的变迁 被引量:1
6
作者 刘祥学 《古今农业》 2012年第4期59-68,共10页
壮族是典型的稻作民族。明清以来,其农作物的种植结构因受地形、气候等自然地理因素,以及农作物的引进、人口的迁移等人文地理因素的影响,壮族地区农作物种植结构具有显著的特征。主要是平原地区农作物种植的品种不断增加,但水稻种植一... 壮族是典型的稻作民族。明清以来,其农作物的种植结构因受地形、气候等自然地理因素,以及农作物的引进、人口的迁移等人文地理因素的影响,壮族地区农作物种植结构具有显著的特征。主要是平原地区农作物种植的品种不断增加,但水稻种植一直占据绝对的主导地位,而玉米、麦等杂粮在种植结构中的比重,大致呈由平原、丘陵向山地不断提升的趋势。这种变化正是壮族适应边疆民族地区农业地理环境的结果。 展开更多
关键词 明清 壮族 种植结构 环境适应
下载PDF
Estimating Reduced-Reference Video Quality for Quality-Based Streaming Video
7
作者 Luigi Atzori Alessandro Floris +1 位作者 Giaime Ginesu Daniele D. Giusto 《ZTE Communications》 2013年第1期17-26,共10页
Reduced-reference (RR) video-quality estimators send a small signature to the receiver. This signature comprises the original video content as well as the video stream. RR quality estimation provides reliability and... Reduced-reference (RR) video-quality estimators send a small signature to the receiver. This signature comprises the original video content as well as the video stream. RR quality estimation provides reliability and involves a small data payload. While significant in theory, RR estimators have only recently been used in practice for quality monitoring and adaptive system con- trol in streaming-video frameworks. In this paper, we classify RR algorithms according to whether they are based on a) model- ing the signal distortion, b) modeling the human visual system, or c) analyzing the video signal source. We review proposed RR techniques for monitoring and controlling quality in streaming video systems. 展开更多
关键词 reduced-reference quality estimation video streaming adap-tive rate control
下载PDF
Catalase promotes whitefly adaptation to high temperature by eliminating reactive oxygen species
8
作者 Peng Liang Jie Ning +4 位作者 Wenlu Wang Pu Zhu Lianyou Gui Wen Xie Youjun Zhang 《Insect Science》 SCIE CAS CSCD 2023年第5期1293-1308,共16页
Thermal stress usually leads to excessive production of reactive oxygen species(ROS)in all aerobic organisms.Catalases(CAT)are the key antioxidant enzymes,which act as the first line of defense against ROS in the anti... Thermal stress usually leads to excessive production of reactive oxygen species(ROS)in all aerobic organisms.Catalases(CAT)are the key antioxidant enzymes,which act as the first line of defense against ROS in the antioxidant pathway.The highly invasive and widely distributed whitefly Bemisia tabaci MED damages plants by feeding as well as by transmitting many plant viruses.Previous studies have shown that strong adaptability to high temperature helps explain the spread of MED around the world.However,the mechanism underlying high temperature adaptation of this pest is not well understood.In this study,6 CAT genes were identified from the MED genome and transcriptome dataset,among which BtCAT1,BtCAT2,and BtCAT3 were found to be highly expressed in adults.The expression of BtCAT1,BtCAT2,or BtCAT3 increased with induction temperature and induction time.The MED was exposed with mean high temperature(30℃ or 35℃)and a short-term extremely high temperature(39℃ or 41℃)after the silencing of BtCAT1,BtCAT2,or BtCAT3 to significantly increased ROS levels by at least 0.5 times and significantly decreased survival rate and fecundity of MED adults.The ROS level in the treated specimens gradually returned to a normal level after 24 h at 25℃,but the survival rate still declined significantly.Taken together,our results demonstrate that CAT could help B.tabaci adapt to long-term mean high temperatures and short-term extremely high temperatures by eliminating excessive ROS. 展开更多
关键词 CATALASE FECUNDITY reactive oxygen species survival rate temperature adap-tation mechanism WHITEFLY
原文传递
产业转型中的就业困境 被引量:5
9
作者 刘大勇 余泳泽 陆晓召 《财经科学》 CSSCI 北大核心 2012年第12期65-72,共8页
本文通过产业价值链分析,指出在原有的国际产业分工格局下,中心、外围国家的产业人才需求与劳动力供给存在明显的不匹配。对此,本文运用均衡匹配搜寻模型,以产业因素变量和搜寻成本变量作为解释变量,将就业匹配变量内生化,运用比较静态... 本文通过产业价值链分析,指出在原有的国际产业分工格局下,中心、外围国家的产业人才需求与劳动力供给存在明显的不匹配。对此,本文运用均衡匹配搜寻模型,以产业因素变量和搜寻成本变量作为解释变量,将就业匹配变量内生化,运用比较静态方法分析表明:提升产业适应系数、降低搜寻成本可以提高搜寻效用。产业转型是中心、外围国家分别解决就业问题的根本途径是:发达国家进行再工业化,发展中国家从依靠要素投入到依靠生产效率提高转变。 展开更多
关键词 中心-外围 产业链 就业匹配率 产业适应系数
原文传递
Design support tools to sustain climate change adaptation at the local level: A review and reflection on their suitability 被引量:1
10
作者 Catherine Dubois Genevieve Cloutier +2 位作者 Andre Potvin Luc Adolphe Fiorent Joerin 《Frontiers of Architectural Research》 CSCD 2015年第1期1-11,共11页
For mid-latitude cities, higher summer temperatures due to climate change are a cause for concern because they aggravate the urban heat island phenomenon and reduce thermal comfort inside buildings. By acquiring the a... For mid-latitude cities, higher summer temperatures due to climate change are a cause for concern because they aggravate the urban heat island phenomenon and reduce thermal comfort inside buildings. By acquiring the appropriate knowledge and skills, architects and urban designers can become key actors in adaptation to climate change. Two workshops bringing together architects and urban designers provided evidence of deficiencies in this area. We hypothesize that a design support tool (DST) focused on the issue of adaptation of mid- latitude cities to rising summer temperatures could help improve knowledge and skills of professionals in the field. The first section presents the results taken from a review and classification of DSTs, which highlight the toots' features that are LikeLy to reach this goal Toots of the "hybrid" category seem most appropriate. To verify this, seven DSTs were selected and tested by fourteen students enrolled in a graduate-level architecture design studio. The second section presents the results from this test, including an analysis of the final projects, a web- based questionnaire and two focus groups. The relevance of hybrid approaches is established, but the results bring into question the capacity of a single DST to meet the individual and multiple needs of professionals. 展开更多
关键词 Climate chanse adap-tation Mid-Latitude cities ARCHITECTS Urban designers Design support too[ Architecture designstudio
原文传递
A less complicated adaptive equalization for UWB channels
11
作者 WANG Yi-ming ZHU Hong-bo 《Frontiers of Electrical and Electronic Engineering in China》 CSCD 2006年第3期319-324,共6页
In this paper,a new adaptive equalization scheme aiming at the intersymbol and interuser interfer-ences in the multiuser ultra-wide band(UWB)channels is presented specially for direct-sequence UWB/time-hopping UWB(DS-... In this paper,a new adaptive equalization scheme aiming at the intersymbol and interuser interfer-ences in the multiuser ultra-wide band(UWB)channels is presented specially for direct-sequence UWB/time-hopping UWB(DS-UWB/TH-UWB)receivers.Its computational complexity and convergence rate are compared with the conventional algorithms.The simulation results show that the computational complexity of this scheme is less than employing the RLS method alone and the convergence rate of this scheme is farther off employing LMS method alone. 展开更多
关键词 UWB receiver channel characteristics adap-tive equalization CONVERGENCE computational complexity
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部