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针对股骨颈骨折空心钉手术中的空间定位问题,提出了一种基于射影变换的双平面空间定位算法,并为其建立了数学模型;在此基础上,采用蒙特卡罗法对定位算法的精度进行了理论推导,并用Matlab对系统精度进行了仿真,对仿真结果进行了分析,得到了系统精度;分组比较了定位算法中各输入量对算法精度的影响程度,并对误差分布规律进行仿真,得到误差分布规律.仿真发现当目标点处于两参考坐标系平面之内,且标记点靠近X光发射源时精度较高,本文依据上述分析结果从标尺结构、图像采集和物理量的优化等方面提出定位算法修改建议. 相似文献
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虚拟光学加密系统的仿真与性能分析 总被引:1,自引:0,他引:1
光学加密机制的研究近来引起了人们的重视.针对光学加密参数对密文安全性的影响问题,本文研究了加密参数与密文的影响关系,为虚拟光学加密系统设计提供安全性理论基础.论文给出了系统的实现算法,设计实现了加密仿真系统,然后对二维码进行了仿真实验与分析,验证了算法的正确性,从衍射距离、光波波长、随机模板、透镜焦距等参数对加密系统的安全性影响进行了仿真讨论,仿真结果表明光波波长对加密系统的安全影响最大,同时参数对安全性的影响存在非线性关系.论文最后讨论了可进一步研究的问题. 相似文献
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高速高机动目标的被动定位跟踪在理论上和实践上均有较高的技术难度,传统的定位算法难以同时满足定位精度和实时性的要求.本文以交互式多模型算法(IMM)为框架,根据多速率跟踪(MRT)的思想,实现了模式空间与测量空间的多速率混合滤波,并给出了多速率常高通(CH)和常高高通(CH2)模型的统一表示形式.同时,引入自适应"当前"统计模型对高度机动的运动模型进行刻画,在此基础上,根据各模型假定的机动性,多模型综合选配了粒子滤波算法和卡尔曼滤波算法,从而建立了高速高机动目标的多速率交互式多模型跟踪算法.实验结果表明,与传统的跟踪算法相比,本文算法定位精度高,误差小于4%斜距;运算复杂度低,具有高于25 Hz的速率更新目标状态的能力. 相似文献
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研究了单矢量传感器多重信号分类(SV-MUSIC)算法对非相干源的分辨性能,推导了声源等功率情况下的信噪比分辨门限表达式.针对相干源的分辨问题,提出了一种基于空间平滑的二元矢量阵多重信号分类(DV-MUSIC)算法.仿真实验表明,SV-MUSIC算法对非相干源的分辨能力随着信噪比的增加而提高,在相应的判定准则下其结果与理论值基本吻合,而基于二元矢量传感器的DV-MUSIC算法能够实现相干源的分辨,其分辨性能曲线一定程度上类似于SV-MUSIC算法对非相干源的分辨性能曲线. 相似文献
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通过实证研究,分析了单件离散型生产作业排程特征和设备对排程的重要性,提出了从设备使用和顾客需求角度研究作业排程优化的必要性.引入设备综合技术性能指数作为质量保证的考量指标,以精益物流为指导思想,综合质量保证指数、生产浪费指数和准时交货指数三项指标,以生产能力、工艺时序、随机不确定性因素为约束条件,建立了组合优化模型.为了有效地求解模型,设计了集成算法,并结合实例分别应用“SM&PR”(仿真&优先规则)和“SM&PR&GA”(仿真&优先规则&遗传算法)进行了仿真试验,检验了模型和算法的有效性.结果显示“SM&PR&GA”是最有效的方法,与传统方法相比,具有动态随机性、全局收敛性和智能性等特征,提高了作业排程的效率和科学性. 相似文献
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采用老年人听力障碍(Hearing Handicap Inventory for the Elderly,HHIE)量表在广州市内随机调查了582名60岁以上老年人,获取广州市内老年人的听力状况,探讨老年人的听力状况与各因素之间的关系。统计结果显示:广州市老年人听力障碍患病率是42.1%;高龄老人更易因听力问题而影响日常生活和身心健康,且70岁左右的年龄是老年人听力损失的敏感年龄;有听力障碍的老年人使用助听器的比重较低且多集中在大于75岁的高龄段,使用助听器的老年人多为重度听力障碍者,双耳使用助听器的老年人的HHIE得分显著高于单耳使用助听器的老年人。 相似文献
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In this work, the electromagnetic interference on hearing aids was evaluated. Electromagnetic (EM) immunity tests on different types of hearing aids were carried out, using signals of intensity and modulation comparable to those present in the environment. The purpose of this work is to characterise the interference, establishing the immunity threshold for different frequencies and finding out which types of hearing aids are more susceptible, and in which frequency range. The tests were carried out in a GTEM cell on seven hearing aids, using AM and GSM signals in the radiofrequency (RF) range. 相似文献
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3- and 4-element spring and dashpot models have frequently been applied to the behaviour of some visco-elastic materials, although somewhat less frequently to wood and wood-based sheet materials which are themselves visco-elastic. However there exists a need to develop a good analytical procedure for fitting the non-linear response curves corresponding to these models to experimental data. This paper describes such a method and applies it to the data from a creep experiment on UF chipboard bending specimens under sustained three-point loading. The computer program written for the solution process illustrates the response curves on a graph plot. 相似文献
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Kinetic and equilibrium study for the sorption of cadmium(II) ions from aqueous phase by eucalyptus bark 总被引:2,自引:2,他引:0
The efficiency of eucalyptus bark as a low cost sorbent for removing cadmium ions from aqueous solution has been investigated in batch mode. The equilibrium data could be well described by the Langmuir isotherm but a worse fit was obtained by the Freundlich model. The five linearized forms of the Langmuir equation as well as the non-linear curve fitting analysis method were discussed. Results show that the non-linear method may be a better way to obtain the Langmuir parameters. Maximum cadmium uptake obtained at a temperature of 20 degrees C was 14.53mgg(-1). The influence of temperature on the sorption isotherms of cadmium has been also studied. The monolayer sorption capacity increased from 14.53 to 16.47 when the temperature was raised from 20 to 50 degrees C. The DeltaG degrees values were negative, which indicates that the sorption was spontaneous in nature. The effect of experimental parameters such as contact time, cadmium initial concentration, sorbent dose, temperature, solution initial pH, agitation speed, and ionic strength on the sorption kinetics of cadmium was investigated. Pseudo-second-order model was evaluated using the six linear forms as well as the non-linear curve fitting analysis method. Modeling of kinetic results shows that sorption process is best described by the pseudo-second-order model using the non-linear method. The pseudo-second-order model parameters were function of the initial concentration, the sorbent dose, the solution pH, the agitation speed, the temperature, and the ionic strength. 相似文献
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在噪声环境中助听器的性能会受到严重影响。但当噪声与期望信号处在不同方向时,在助听器中使用指向性传声器系统能够有效地抑制噪声,使助听器的使用者受益。在复杂环境中采用自适应指向性的传声器系统能够动态调整指向性模式,以适应噪声的变化情况。基于自适应最小均方(LMS)算法提出了一种新的适用于助听器的自适应算法,用以动态调整传声器系统中滤波器的系数,使指向性模式的灵敏度最低点朝向噪声源方向,达到降噪的目的。相比于经典的LMS算法,该算法有效改善了期望信号存在时的失调情况。通过仿真结果讨论了算法中关键参数的选取对于失调并和收敛速度的影响。 相似文献
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A comparative study of linear and non-linear regression analysis for ammonium exchange by clinoptilolite zeolite 总被引:2,自引:0,他引:2
Ammonium ion exchange from aqueous solution using clinoptilolite zeolite was investigated at laboratory scale. Batch experimental studies were conducted to evaluate the effect of various parameters such as pH, zeolite dosage, contact time, initial ammonium concentration and temperature. Freundlich and Langmuir isotherm models and pseudo-second-order model were fitted to experimental data. Linear and non-linear regression methods were compared to determine the best fitting of isotherm and kinetic model to experimental data. The rate limiting mechanism of ammonium uptake by zeolite was determined as chemical exchange. Non-linear regression has better performance for analyzing experimental data and Freundlich model was better than Langmuir to represent equilibrium data. 相似文献