无线网络接入点TCP流时间公平性

对无线网络接入点上下行TCP流存在的时间不公平性现象进行了研究,报告了无线网络接入有线网络存在的拥塞控制问题现状,提出了一种的无线网络TCP流公平调度算法。采用快速的TCP流优先发送方法,既保证了各流吞吐率公平性,又解决了慢速的TCP占用信道时间过多的问题,实现了各流占用信道的时间公平性。通过网络仿真实验证明,新的公平调度算法比传统的算法在性能上有较大的改进,达到了提高网络整体效率的目的。     

区域作物旱灾产量和经济损失定量估算——以唐山地区为例

以1991a-2006a唐山地区夏粮作物旱灾面积为基础,从产量损失和经济损失两方面对旱灾损失进行了估算。结果显示：⑴1991a-2006a夏粮因旱累计减产17.99×108kg,平均每年减产1.12×108kg;产量损失最大年份为1999a（减产2.2×108kg）,产量损失最小年份为2006a（减产0.2×108kg）;（2）按1990a不变价格计算,累计经济损失15.3×108元,平均每年损失0.96×108元。按当年价格计算,累计经济损失19.6×108元,平均每年损失1.2×108元;（3）减产利润损失最大年份为1995a（利润损失为0.68×108元）,利润损失最小年份为2000a（利润损失为-178.4×104元）。不变价格和当年价格计算的经济损失以及产量损失与利润损失间的非一致性,对农业保险政策的制定具有一定的借鉴作用。     

基于随机森林法的棉花叶片叶绿素含量估算

为了高效和无损地估算棉花叶片的叶绿素含量,本研究测定了棉花光谱反射率及叶绿素含量(soilandplant analyzerdevelopment,SPAD)值,对光谱数据进行包络线去除处理、立方根转换和倒数转换,以SPAD值与反射光谱之间的相关性为基础,通过随机森林法筛选出对棉花叶片SPAD值影响较大的特征波段,构建估算棉花叶片SPAD值的BP神经网络(back propagation artificial neural networks, BP ANN)、偏最小二乘回归(partial least squares regression,PLSR)两个模型。结果表明,在605～690nm范围内的反射率与SPAD值相关性达0.01显著水平,均呈负相关,相关系数最高值为-0.619。与原始光谱相比,经过变换后的棉花反射率与SPAD值相关性结果相差较大,其中去除包络线光谱在550～750 nm波段范围有效提高了相关性,相关性效果优于倒数转换数据和立方根转换数据。随机森林法能够有效评出对SPAD值影响较大的特征波段,进而提高模型估算精度。在两种模型中,基于去除包络线光谱建立的PLSR和BP神经网络模型的决定系数R~2分别为0.92、0.83,说明这两种模型的估算能力较好;两种模型RMSE分别为0.88、1.26, RE分别为1.30%、1.89%,表明PLSR模型的估算精度比BP神经网络模型高。从模型的验证效果来看,PLSR模型在估算棉花SPAD值方面有一定的优势和参考价值。     

RR-CETEN Algorithm: Making TC PMore Robust Against Spurious Retransmissions

Numerous studies have shown that packet reordering is common,especially at wireless and Satellite networks where there are high degree of parallelism and different link speeds.Packets reordering decreases TC Pperformance,because it leads to over estimation of network congestion.The CETEN(Cumulative Explicit Transport Error Notification) has solved the overestimation caused by packet corruption.However,it does not consider the reordering at wireless network,which makes the LEAST(Loss Estimations AlgorithmS for TCP) loss rate value imprecise.The solution is based on explicit spurious retransmit notification at receiver side,and signals the sender packet loss caused by reordering packet.This mechanism can improve precision of LEAST and make the TC Pmore robust.The method is showed efficient in experiment.     

Speed Estimation Methods Based on Neural Network

In order to solve the speed estimation problems of speed sensorless vector-controlled induction motor drives, the paper presents two speed estimation schemes based on neural network mode identification theory. The advantages of each scheme are discussed and the simulation results show that the estimated speed can trace the actual speed better (even under the circumstances of load variation or speed step variation). Also, these schemes are not sensitive to the variations of motor parameters and the effect of iron loss. Therefore, the proposed neural network based on speed sensorless vector-controlled induction motor drives have good performance in stady-state and transient-state operation.     

基于高光谱的水稻土有机质含量估算研究

利用高光谱技术可实现土壤有机质含量的快速、精确反演。然而运用不同的光谱预处理算法及建模方法获取的模型预测精度及稳定性不同。为了选取最佳土壤有机质估算模型,本研究应用ASD波谱仪测定河南省潢川县水稻土的光谱数据,比较使用2种建模方法组合18种光谱预处理转换算法建立模型的反演效果。对于多元逐步回归模型和偏最小二乘模型,使用SGF3-2预处理算法均获得了最佳的预测效果,所建模型具有较小的误差和较高的精度。相比使用多元逐步回归法,使用偏最小二乘回归法可以获取更稳定的预测模型。运用偏最小二乘模型结合SGF3-2预处理算法得到了最佳的水稻土有机质含量估算模型,模型预测均方根误差RMSEv=0.036,决定系数Rv2=0.89。选择最佳的建模方法结合预处理算法,可以改进模型反演精度。本研究对比的不同方法也可以应用到类似的土壤模型选取中。     

Cell Loss Analysis Based ATM Networks of On-Off Traffic Source

Cell loss, which occurs when buffers overflow in ATM switches, is a key measure for the performance of an ATM network .An ATM network must be designed for very low and predictable cell loss probabilities to provide adequate quality of service for all users. Many methods have been proposed for allocating bandwidth and determining buffer size requirements to provide quality of service guarantees. These methods are subject to overly optimistic allocations or overly pessimistic allocations. The authors present an exact analysis of cell for on off traffic source which can be used in concert with probabilistic methods to ensure that buffer and bandwidth allocation are mode between the best case and worst case requirements.     

耕层土壤含水量间接光谱估测模型

为克服光学卫星遥感只能获取表层土壤光谱信息而不能用于直接估测耕层土壤含水量的局限性,建立基于表层土壤高光谱的耕层土壤含水量间接估测模型。以山东省济阳县85个潮土样本的含水量及高光谱数据为基础,根据表层与耕层土壤含水量的内在关系,建立耕层土壤含水量间接光谱估测模型。结果表明,表层土壤光谱反射率的对数变换效果较好,以1339、1457、1745、1969、1996 nm波段的对数变换值为估测因子,采用多元线性回归模型建立的表层含水量估测模型的决定系数为R ²=0.8911,平均相对误差为13.67%;土壤耕层与表层含水量之间存在着显著的相关性,R ²=0.8131;耕层土壤含水量间接光谱估测模型的精度较高,决定系数R ²=0.8138,平均相对误差为9.66%。研究表明,山东省济阳县潮土表层、耕层含水量之间存在着显著的相关性,利用表层土壤光谱间接估测耕层土壤含水量是可行有效的。     

Fuzzy Estimation on Cost of Project

This paper discusses 18 factors which control the cost of project according to the constitution of the cost of project.The cost of project is estimated by fuzzy mathematics' method which adopts the principle of fuzzy proximity degree, principle of shortcut and the principle of expert system and which quantifies similarity of some projects finished and one planned.     

新的油菜产量测定方法研究初报

采用取样测数法和合并测产法分别对中双4号、华杂6号甘篮型油菜产量进行了测定。结果表明,合并测产法具有取样测数法获得油菜产量要素及理论产量的优点,且便于操作、减轻了工作量,工作效率高,与实收产量的符合程度高,精确度高,为2．1％,其结果准确可靠。     

花生资源耐盐性的鉴定与评价

为筛选耐盐花生种质并为花生遗传基础研究提供材料,本研究选用相对发芽势、相对发芽率、相对发芽指数和盐害率为指标,以0.5%的NaCl为胁迫浓度,对128份花生种质进行芽期耐盐性鉴定。结果表明,盐胁迫对花生种子萌发有显著的抑制作用,但盐胁迫的抑制效应因种质不同而存在明显差异;128份种质中,高耐盐种质仅占5%左右。在耐盐评价指标方面,除盐害率或相对发芽率以外,相对发芽指数可以作为评价指标之一。此外,盐胁迫条件下,地方品种的发芽速度高于育成品种。本研究筛选出JS011、JS024、JS125、JS491、JS523、JS524、JS525等7份高度耐盐种质可用于花生耐盐性基础研究的材料。     

Application of Magnetic Analysis in Magneto-rheological Damper Performance Estimation

As a kind of semi-active controllable devices,Magneto-rheological(MR) damper has been increasingly widely used in various occasions of vibration suppression.However,the design of MR damper greatly depends on the engineering experience of designers,it is difficult to calculate the performances relatively accurate.With the Finite Element Method,the authors carry out the magnetic analysis on the given geometry of MR damper combined with the Couette flow analysis of MR damper,the dynamic curve of MR damper is obtained.The results show that the FEM magnetic analysis effectively predicts the yield shear force and flow shear force,it is coincident with the experimental data.It is validated that the methods described is suitable for the MR damper performance estimation of the same geometry,and is an effective means for the MR damper design with the given force.     

胡萝卜亲本综合性状评价及遗传通径分析

对胡萝卜２０个亲本的小区产量等１１个性状,采用综合评分法及通径分析法进行分析。结果表明,参试的４个母本不育系,４个父本自交系综合性状较好,分别为Ｓ８,Ｓ４,Ｓ２,Ｓ５和Ｃ９４３,Ｃ９４１,Ｃ９７２,Ｃ９６１。胡萝卜亲本选择选配时,应首先考虑单根重。其次考虑商品产量和收获时最大叶长,同时要兼顾抽苔率、黄收率、髓指数较低的材料。     

利用水稻成熟期冠层高光谱数据进行估产研究

通过大田小区试验,测定了2个品种、3个供氮水平处理的水稻抽穗后不同时期冠层的高光谱反射率、叶面积指数及理论产量和实际产量。结果表明,抽穗后水稻冠层光谱反射率随发育期推移在可见光范围逐渐增大,在近红外区域逐渐减小;理论产量、实际产量与差值植被指数R1200-R680、R990-R680、R800-R680、R1200-R550、R990-R550、R     

Bayesian Estimation of the Censored Life-span Experiment

The censored life-span experiment is very popular. To estimate the expectation of the random variable that only has imperfection samples based on Bayesian method is a method that utilize prior information, and the estimator has a recursive formula, when samples added it is very convenient in calculation. This method is a fusion method of dynamic discrete data. It is more effective than routine estimators.     

Direction of Arrival Estimation for CDMA Communication Signal

MUSIC algorithm is often applied in direction of arrival estimation of communication signal or radar signal. But the traditional MUSIC algorithm is not applicable in the presence of the correlational signals. Combining with time average processing, an algotithm of two-dimensional space-time average is suggested on the base of space average technic especially for the DOA estimation of CDMA communication signal. A detaild analysis and a conclusion about this improved algorithm is presented. Ensuring the accurary of the estimation an efficient decrease in quantity of operation is achieved with the algorithm, so it is more suitable for real-time processing. The efficiency of the improved algorithm is attested by the emulating results.     

Application of Bispectrum Estimation to Analyzing Pulse Signals

According to non-Gaussianity and randomness of the Pulse Signals, the bispectrum estimation is used to analyze the signals for the purpose of extracting the unusual information of the signals of-the drug abusers and educing the judgment of how to distinguish drug abusers from healthy persons. The phase of bispectrum carries the important feature information in signal processing. The feature vector of the average phase information based on the indirect nonparametric bispectrum estimation is extracted and used to analyze the Pulse Signals of 15 heroin addicts and 15 healthy persons. It is found that the average phase Ph of heroin addicts on a specified frequency region is generally lower than that of healthy persons. Using the average phase Ph as characteristic parameter, a critical parameter is determined that is used to classify heroin addicts and healthy persons. Thus, all of the 15 healthy addicts are identified. Only one heroin person is misjudged. Experiment results of classification show that the method is feasible and effective.     

Cost Estimation of Transmission Line Based on Artificial Neural Network

Based on the structure of cost factor in transmission lines project and the characteristic of neural networks, the paper shows up using artificial neural networks to estimate the cost of project and provide a method to investigate them. By analyzing the structure of project cost and influence factor, the paper builds both input and output neural cell for cost of transmission line project. The paper builds the model of artificial neural networks and exports the steps of the algorithmic. The project sample is used in history to train and test the model. At last, the model gets satisfactory result and meets the investigation requirement of engineering budgetary estimation. Therefore, the paper provides an impersonality and quick investigation method for budgetary estimation of power projects.     

Statistical Analysis Based on Non-parametric Estimation of VaR and ES

By using the last nonparametric estimation of VaR and ES, not depending on any distribution, analyze empirically the risk of Shanghai stocks index, explore the method of computing N-day VaR. The results of the exploration indicate that under more samples, there are better results by using nonparametric estimation of VaR and ES. the method of computing N-day VaR by curvilinear regression has better result than that of computing under the normal assumption.