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1.
详细推导了基于功率倒置阵列的线性约束最小方差(LCMV)算法及其递推公式,避免了矩阵求逆的复杂运算。然后在Matlab环境里构建了仿真模型来模拟实际的接收环境和复现阵列接收到的信号,对均匀线阵和圆阵都做了仿真,并得到了相应的阵列波束图,为自适应天线的实用设计提供了参考和依据。仿真结果表明:该算法收敛速度快、易于实现,利用LCMV算法作为自适应算法的功率倒置阵列抗干扰方案适合在强干扰的环境下工作,干扰越强,其对应的零陷越深。  相似文献   

2.
描述了单向时延与发送速率的关系,单向时延最大时探测包的发送速率无限接近可用带宽的大小。基于此原理提出了一种降速包列的可用带宽测量算法(DRChirp)。该算法首先使用快速探测技术,找出可用带宽的上界;然后发送指数递减包列,将测得的单向时延最大和次大的探测包的发送速率加权平均得到可用带宽值。NS2下的实验结果表明,该算法在多跳复杂网络上的测量精度优于经典的可用带宽算法。  相似文献   

3.
目的:迄今尚无比较长期监督下运动训练方案与中期和短期方案对正接受最佳药物治疗的严重慢性心力衰竭(CHF)患者效应的研究。本研究旨在评估接受长期  相似文献   

4.
超宽带(UltraWideband,UWB)生物雷达广泛应用于生命体探测等领域,而人体生命体征信息的非接触检测是其需解决的最主问题。本文利用参数化双谱估计算法分析UWB生物雷达回波信号,以非高斯白噪声激励的AR(AutoRegression)参数模型对信号进行建模,并用带约束的三阶平均法对模型的参数进行估计。在此基础上,提出了一种新的基于UWB的人体目标非接触检测算法,并将该算法与现行的基于功率谱密度的检测算法进行对比、实验结果表明,有人位置点信号和无人位置点信号在双谱域表现出明显的差别特性,新算法能更好地实现人体目标的非接触检测。  相似文献   

5.
本文介绍了分形理论在井约束地震速度分形反演方面的应用原理,提出了具体的方法、计算流程。以新疆焉耆盆地实际资料为例,利用分形理论对波阻抗曲线在实际测井曲线的约束下进行分形计算,进而得到声波约束分形反演剖面,所反演出的声波曲线分辨率有明显提高。  相似文献   

6.
医院通过预测和决策,确定了发展的长期战略目标和短期运营目标,为保证决策方案得以执行,实现既定目标,必须编制未来一定期间的全面预算,对医院的各项活动统筹安排及全面控制。  相似文献   

7.
医院通过预测和决策,确定了发展的长期战略目标和短期运营目标,为保证决策方案得以执行,实现既定目标,必须编制未来一定期间的全面预算,对医院的各项活动统筹安排及全面控制.  相似文献   

8.
针对约束多目标优化问题,提出了一种新型的约束多目标优化算法。该算法采用了一种新型约束处理方式,先通过约束违反门限截取种群再依据约束与目标函数值针对不同情况实现对个体的优劣划分。本算法将差分进化与免疫克隆机制相融合,既利用了差分进化从全局角度进行搜索的特点,又利用了免疫克隆机制从优秀个体出发进行局部再寻优搜索的优点,扩大了算法搜索的广度与深度。测试结果表明该算法相比快速非支配排序遗传算法(NSGA II)具有非常优秀的收敛性与分布性。将提出的算法应用于实际的汽油调合优化中,进一步验证了算法的有效性,可有效减少成本,提高产品质量。  相似文献   

9.
提出了一种用于多用户OFDM系统的资源分配算法(ESFC),能以低复杂度完成用户间的子载波、比特及功率分配,达到快速优化系统发射功率的目的。该算法同时考虑到动态业务的实时性和用户间的公平竞争性,将系统资源分配问题转化为数学模型的多约束优化求解问题。资源分配过程分为两个步骤,包括基于进化策略进行子载波分配和使用注水算法进行比特及功率分配。仿真结果表明:与现有算法相比,该算法能有效降低复杂度,在优化OFDM系统性能的同时兼顾了实时性需求,明显减少了运算量,能快速收敛到优化解。 关键词:OFDM; 进化策略; 子载波分配; 比特分配  相似文献   

10.
完善公司治理结构,其基本目的是为了实现资源配置的最大效率和利益相关之间的最大公平。一个有效的公司治理结构应该是在最大效率与最大公平之间达到均衡的时间点和空间点。从公司治理结构来看,实现公平的根本途径在于实现经济民主,即让职工更多参与公司治理,实现对公司各个利益相关实施激励、选择和制衡。职工参与管理或说企业管理民主化的优势也是显而易见的,如:①职工与企业形成了利益与共、休戚相关的共同体,职工主动性、积极性和创造性的发挥有了动力保证。②职工对企业的长期发展给予更多的关注,而不再盲目追求企业短期利润和红利,企业资产配置更为优化及合理。③职工参与管理,有助于消除职工与企业管理信息不对称的状态,最终有利于企业的长期发展。在经济民主化的浪潮中,最显有效的方式是让职工参与公司管理。笔拟在考察其他国家先进经验的基础上,对完善我国的相关法律制度提出建议。  相似文献   

11.
Wireless personal area network (WPAN) is an emerging in wireless technology for short range indoor and outdoor communication applications. A more specific category of WPAN is the wireless body area network (WBAN) used for health monitoring. On the other hand, multiband orthogonal frequency division multiplexing (MB-OFDM) ultra-wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications, for example, very high data rate. One big challenge in adoption of multiband UWB in WBAN is the fact that channel estimation becomes difficult under the constraint of extremely low transmission power. Moreover, the heterogeneous environment of WBAN causes a dense multipath wireless channel. Therefore, effective channel estimation is required in the receiver of WBAN-based healthcare system that uses multiband UWB. In this paper, we first outline the MB-OFDM UWB system. Then, we present an overview of channel estimation techniques proposed/investigated for multiband UWB communications with emphasis on their strengths and weaknesses. Useful suggestions are given to overcome the weaknesses so that these methods can be particularly useful for WBAN channels. Also, we analyze the comparative performances of the techniques using computer simulation in order to find the energy-efficient channel estimation methods for WBAN-based healthcare systems.  相似文献   

12.
目的:探讨宫腔镜组织切除系统在输卵管间质部妊娠中治疗的可行性及安全性。方法:收集2019年4月至2022年4月江西省妇幼保健院妇科收治的采用宫腔镜组织切除系统治疗的16例未破裂型输卵管间质部妊娠患者的临床资料,回顾性分析患者的术前血β-人绒毛膜促性腺激素(beta-human chorionic gonadotropin,β-HCG)、B超情况、手术时间、术中出血量及术后血β-HCG正常时间等。结果:16例未破裂型输卵管间质部妊娠患者术前血β-HCG值为830~31 153 mIU/mL,平均(8 643.561±1 752.000) mIU/mL,B超下妊娠物最大为33 cm×28 cm,最小为11 cm×10 cm。均在检查镜下明确诊断为输卵管间质部妊娠,使用宫腔镜组织切除系统行间质部妊娠病灶清除术,其中2例中转腹腔镜,平均手术时间为34(20,92) min,平均术中出血量为46.6(10,250) mL,术程顺利,无明显并发症。术后平均住院时间2 d,血β-HCG恢复正常时间为(22.00±5.11) d,术后1个月复查B超均未见妊娠组织残留,术后半年随访过程中共5例患者成功受...  相似文献   

13.
The paper presents a network coded cooperative communication (NC-CC) enabled wireless hospital sensor network architecture for monitoring health as well as postural activities of a patient. A wearable device, referred as a smartband is interfaced with pulse rate, body temperature sensors and an accelerometer along with wireless protocol services, such as Bluetooth and Radio-Frequency transceiver and Wi-Fi. The energy efficiency of wearable device is improved by embedding a linear acceleration based transmission duty cycling algorithm (NC-DRDC). The real-time demonstration is carried-out in a hospital environment to evaluate the performance characteristics, such as power spectral density, energy consumption, signal to noise ratio, packet delivery ratio and transmission offset. The resource sharing and energy efficiency features of network coding technique are improved by proposing an algorithm referred as network coding based dynamic retransmit/rebroadcast decision control (LA-TDC). From the experimental results, it is observed that the proposed LA-TDC algorithm reduces network traffic and end-to-end delay by an average of 27.8% and 21.6%, respectively than traditional network coded wireless transmission. The wireless architecture is deployed in a hospital environment and results are then successfully validated.  相似文献   

14.
针对自适应OFDM系统中满足用户QoS(这里主要指用户带宽及误码率这两个指标)要求的资源(比特功率)分配这一问题,提出了一种新的算法。该算法以每次比特分配时,使得每比特(一次可分配多比特信息)的功率代价最小为原则,获得了良好的性能。仿真结果表明:该算法在满足用户QoS要求的情况下,其发射总功率比现有的同类算法小,性能更佳。  相似文献   

15.
码辅助的迭代同步算法将编码增益引入到同步环路中,能够有效实现低信噪比环境下的载波同步。针对低信噪比条件下码辅助同步算法存在参数估计范围小的问题,提出了基于最优化搜索的迭代载波同步算法。该算法通过研究载波偏差与译码软信息的关系,得出一种较简单的评价函数,再利用均匀搜索方式结合改进的Powell算法来获取同步参数的最佳估计,以实现准确的载波恢复。仿真实验验证了该算法在低信噪比条件下,能够有效补偿载波偏移,且具有较大的同步范围,在一定迭代次数之后可逼近理想同步。  相似文献   

16.
A real-time cooperative communication based wireless network is presented for monitoring health and activity of an end-user in their environment. The cooperative communication offers better energy consumption and also an opportunity to aware the current location of a user non-intrusively. The link between mobile sensor node and relay node is dynamically established by using Received Signal Strength Indicator (RSSI) and Link Quality Indicator (LQI) based on adaptive relay selection scheme. The study proposes a Linear Acceleration based Transmission Power Decision Control (LA-TPDC) algorithm to further enhance the energy efficiency of cooperative communication. Further, the occurrences of false alarms are carefully prevented by introducing three stages of sequential warning system. The real-time experiments are carried-out by using the nodes, namely mobile sensor node, relay nodes and a destination node which are indigenously developed by using a CC430 microcontroller integrated with an in-built transceiver at 868 MHz. The wireless node performance characteristics, such as energy consumption, Signal-Noise ratio (SNR), Bit Error Rate (BER), Packet Delivery Ratio (PDR) and transmission offset are evaluated for all the participated nodes. The experimental results observed that the proposed linear acceleration based transmission power decision control algorithm almost doubles the battery life time than energy efficient conventional cooperative communication.  相似文献   

17.
对于多输入多输出系统,传统的基于训练序列的信道辨识方法为跟踪信道的变化,必须发送大量冗余信息,传输效率较低;而基于子空间的纯盲方法又带有不可避免的模糊性,辨识结果精度不够。在子空间法的基础上,利用少量训练符号估计出模糊矩阵,以此矫正子空间法得到的结果。仿真结果显示:在保证辨识精度的前提下,该方法减少了训练符号等冗余,提高了传输效率。  相似文献   

18.
目的:设计一种基于无线传感网络的多参数体征监测仪,取代传统有线式数据传输,提高便携式心电监测仪的适应能力。方法系统采用Zigbee无线传感技术,对人体心电、血氧饱和度、无创血压等生命体征参数进行动态监测,并通过小波变换对心电监测算法进行改进,提高心电监测的分辨率和精准度。结果实现了各种医疗监测模块的即插即用功能,以及特征监测数据的网络化传输。结论网络化心电检测仪结构简单、精度高、系统功耗低。  相似文献   

19.
Telemedicine involves the use of advanced and reliable communication techniques to deliver biomedical signals over long distances. In such systems, biomedical information is transmitted using wireline or wireless communication systems. Mobile telemedicine is an improved form of telemedicine, in which advanced wireless communication systems are used to deliver the biomedical signals of patients at any place and any time. Mobile telemedicine employs advanced concepts and techniques from the fields of electrical engineering, computer science, biomedical engineering, and medicine to overcome the restrictions involved in conventional telemedicine and realize an improvement in the quality of service of medicine. In this paper, we study several mobile telemedicine systems, and it is important to gain a good understanding of mobile telemedicine systems because in the further, such systems are expected to become ubiquitous for the delivery of biomedical signals for medicine.  相似文献   

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