Joint Optimization of Satisfaction Index and Spectrum Efficiency with Cache Restricted for Resource Allocation in Multi-Beam Satellite Systems

Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under restricted cache resources is also an important issue to be studied. This paper mainly investigates the DRA problem of carrier resources under certain cache constraints. What's more, with the aim to satisfy all users' traffic demands as more as possible, and to maximize the utilization of the bandwidth, we formulate a multi-objective optimization problem(MOP) where the satisfaction index and the spectrum efficiency are jointly optimized. A modified strategy SA-NSGAII which combines simulated annealing(SA) and non-dominated sorted genetic algorithm-II(NSGAII) is proposed to approximate the Pareto solution to this MOP problem. Simulation results show the effectiveness of the proposed algorithm in terms of satisfaction index, spectrum efficiency, occupied cache, and etc.

基于可逆元胞自动机加密的扩展码索引调制方案

针对直接序列扩频系统伪随机(Pseudo Noise,PN)码资源有限且码索引调制系统误码率性能下降的问题,提出了一种基于可逆的初等元胞自动机加密的扩展码索引调制方案。首先,针对PN码资源有限的问题,提出使用混沌规则的初等元胞自动机对PN码进行迭代的方案,从而实现扩展PN码的目的;其次,针对码索引调制误码率性能下降的问题,提出了一种可逆元胞自动机加密的码索引调制方案,在发射端,把信息比特切割成调制比特和映射比特,并分别映射为调制符号和扩频码索引,使用对应索引的扩频码对同相分量进行扩频,同时使用可逆元胞自动机对映射比特进行加密,加密后的映射比特为调制符号的正交分量选取对应索引的扩频码进行扩频。仿真与分析结果表明,在相同频谱效率条件下,在加性高斯白噪声信道中,当误码率为10-5时,扩展码索引调制方案的误码率性能优于码索引调制和广义码索引调制方案约2~4 dB,优于非正交码移键控码索引调制方案约0.5 dB。

等离激元银金属膜耦合氮化硅纳米空腔在可见光-近红外区间的多谱带完美吸收和传感性质的仿真研究

具有多谱带完美吸收效应的超构材料在光学滤波和折射率传感等多种应用中是理想的材料。提出了一种由银金属上的氮化硅介电纳米空腔阵列组成的多谱带窄带完美吸收超构材料。有限元仿真给出了四个最高可达99.9%的吸收峰,以及最小达到0.74 nm的吸收峰宽。这些吸收谱带来自于表面晶格模式和三个表面等离激元极化子模式。此外,这些模式的谱峰对超构材料几何外形和环境介质光学参数的变化敏感,从而在可见光-近红外范围内可以被调控。用于折射率传感时,其具有347 nm每折射率单位的灵敏度,Figure of Merit达到469。这些特性令这一材料适用于光学滤波器和折射率传感器等用途。

基于加权相位延迟指数的阿尔茨海默病静息态脑电图定量分析

目的分析阿尔茨海默病(AD)、轻度认知功能障碍(MCI)患者定量脑电图的特征,探讨定量脑电图在早期检测和评估认知衰退方面的效用。方法本研究选取AD患者、MCI患者和认知功能正常的老年人作为研究对象,采用64导脑电图记录静息状态下脑电信号,通过加权相位延迟指数(wPLI)分析人组患者全脑功能连接的差异性。结果AD组在θ频段的相对功率超过对照组,在β频段则低于对照组。此外,三组间的功能连接呈现差异性。在θ和频段,AD组不同脑区之间的相位同步性增强。而在α频段中,AD组局部脑区之间功能连接强度减弱。同时,θ和β频段下的全脑电极平均相功率改变均与临床认知评估量表呈现相关关系。结论定量脑电图分析显示AD患者脑波存在频率慢化的特点。另外,AD患者同时存在脑网络皮层神经通路功能代偿和失连接现象。

一些关联图的拉普拉斯谱和基尔霍夫指标

基于图G,定义了三种关联图G_(1),G_(2)和G_(3),其拉普拉斯矩阵可以经过恰当排序表出。利用图论和行列式的性质以及代数组合的方法,研究这些关联图的拉普拉斯谱和基尔霍夫指标,最后得出了相应的结果。

一种快速的雷达天线扫描周期估算方法

针对传统自相关方法计算量较大的问题,提出了一种快速的雷达天线扫描周期估算方法。首先,分析了接收脉冲幅度序列的离散化频谱特性。其次,通过检测频谱峰值构造频率索引集合。在此基础上,基于频谱峰值的频率索引差分估算雷达天线扫描周期,该方法具有较低的计算复杂度。最后,仿真实验验证了所提方法的有效性。

基于SSA-Hurst-ARIMA组合模型的船舶柴油发电机组故障特征短期预测

为提高船舶柴油发电机组故障特征短期预测精度,建立基于奇异谱分析(Singular Spectrum Analysis,SSA)、Hurst指数、自回归移动平均(Auto-Regressive Integrated Moving Average,ARIMA)的组合预测模型。以某试验中船舶柴油发电机组运行数据为基础,选取增压器滑油压强数据,对比分析单一ARIMA模型、SSA主成分-ARIMA组合模型和SSA-Hurst-ARIMA组合模型的预测效果。结果表明,SSA-Hurst-ARIMA组合模型的预测效果优于单一ARIMA模型和SSA主成分-ARIMA组合模型,更适合应用于船舶柴油发电机组故障特征的短期预测。

Spectrum-Effect Relationship Between High Performance Liquid Chromatography Fingerprints and Anticoccidial Activities of a Compound Chinese Medicine

Quality control and screening of active substances in traditional Chinese medicines have been performed using fingerprint analysis. The spectrum-effect relationship between chromatography fingerprints and efficacy of herbal drugs is considered as a potentially useful method for determining active ingredients in complex mixtures. The study was designed to develop a method for determining the bioactive components of a compound Chinese medicine called Tiefeng based on spectrum-effect relationships between high-performance liquid chromatography （HPLC） fingerprints and anticoccidial activities. Four peaks of the established HPLC fingerprint indicate the main bioactive components of this medicine. In addition, pharrnacodynamic atlas was defined and used to assess the anticoccidial activity of Tiefeng from different sources for the first time. We found that the level of anticoccidial activity of Tiefeng was consistent with the degree of similarity between the pharmacodynamic atlas and chromatogram of any sample. Furthermore, effect of this medicine was related with the main active constituents, along with the origin and the harvesting time.

Inversion of Biochemical Parameters by Selection of Proper Vegetation Index in Winter Wheat

Recent studies have demonstrated the application of vegetation indices from canopy reflectedspectrum for inversion of chlorophyll concentration. Some indices are both response tovariations of vegetation and environmental factors. Canopy chlorophyll concentration, anindicator of photosynthesis activity, is related to nitrogen concentration in green vegetationand serves as an indicator of the crop response to soil nitrogen fertilizer application. Thecombination of normalized difference vegetation index (NDVI) and photochemical reflectanceindex (PRI) can reduce the effect of leaf area index (LAI) and soil background. The canopychlorophyll inversion index (CCII) was proved to be sensitive to chlorophyll concentration andvery resistant to the other variations. This paper introduced the ratio of TCARI/OSAVI to makeaccurate predictions of winter wheat chlorophyll concentration under different cultivars. Itindicated that canopy chlorophyll concentration could be evaluated by some combined vegetationindices.

New Vegetation Index and Its Application in Estimating Leaf Area Index of Rice

Leaf area index （LAI） is an important characteristic of land surface vegetation system, and is also a key parameter for the models of global water balancing and carbon circulation. By using the reflectance values of Landsat-5 blue, green and red channels simulated from rice reflectance spectrum, the sensitivities of the bands to LAI were analyzed, and the response and capability to estimate LAI of various NDVIs （normalized difference vegetation indices）, which were established by substituting the red band of general NDVI with all possible combinations of red, green and blue bands, were assessed. Finally, the conclusion was tested by rice data at different conditions. The sensitivities of red, green and blue bands to LAI were different under various conditions. When LAI was less than 3, red and blue bands were more sensitive to LAI. Though green band in the circumstances was less sensitive to LAI than red and blue bands, it was sensitive to LAI in a wider range. When the vegetation indices were constituted by all kinds of combinations of red, green and blue bands, the premise for making the sensitivity of these vegetation indices to LAI be meaningful was that the value of one of the combinations was greater than 0.024, i.e. visible reflectance （VIS）〉0.024. Otherwise, the vegetation indices would be saturated, resulting in lower estimation accuracy of LAI. Comparison on the capabilities of the vegetation indices derived from all kinds of combinations of red, green and blue bands to LAI estimation showed that GNDVI （Green NDVI） and GBNDVI （Green-Blue NDVI） had the best relations with LAI. The capabilities of GNDVI and GBNDVI to LAI estimation were tested under different circumstances, and the same result was acquired. It suggested that GNDVI and GBNDVI performed better to predict LAI than the conventional NDVI.

Bounds of the Estrada index of graphs

Let G be a graph of order n and let λ1, λ2,...,λn be its eigenvalues. The Estrada index[2] of G is defined as EE = EE（G） =∑i=1^n e^λi.In this paper, new bounds for EE are established, as well as some relations between EE and graph energy E.

基于双能量CT中双能量指数、原子序数结合能谱曲线斜率对于鉴别泌尿系结石成分的价值研究

目的:评估双能量计算机体层扫描(DECT)的双能量指数(DEI)、有效原子序数(Zeff)结合能谱曲线斜率在鉴别患者泌尿系结石成分的价值。方法:收集2019年10月至2022年10月在南通市海门区人民医院就诊的111例泌尿系结石患者的临床及DECT影像资料。所有患者泌尿系结石直径均>5 mm,所有患者的离体结石均经红外光谱分析确定结石成分。分别计算DEI、Zeff、能谱曲线斜率及三者结合对于鉴别泌尿系结石成分的准确率、灵敏度、特异度等。结果:111例患者中草酸钙结石75例(占67.57%),羟基磷灰石15例(占13.51%),尿酸结石21例(占18.92%),未发现胱氨酸等其他类型结石。3种类型结石的CT值(F=487.691,P<0.001)、DEI(F=395.553,P<0.001)、Zeff(F=818.689,P<0.001)和能谱曲线斜率(H=19.615,P<0.001)比较的差异均有统计学意义。DEI、Zeff和能谱曲线斜率对鉴别泌尿系结石成分的总准确率分别为87.39%(97/111)、84.68%(94/111)和81.98%(91/111)。DEI、Zeff和能谱曲线分别对草酸钙结石、羟基磷灰石及尿酸结石诊断准确率均为80%~100%。DEI、Zeff结合能谱曲线斜率对鉴别泌尿系结石成分的总准确率为94.59%(105/111)。DEI、Zeff结合能谱曲线斜率对草酸钙结石、羟基磷灰石及尿酸结石诊断的准确性分别为94.59%、94.59%和100%。结论:与DECT的单个指标相比,DEI、Zeff结合能谱曲线斜率对鉴别泌尿系结石成分显示出更好的诊断准确率。

基于无人机多光谱遥感的矮林芳樟光合参数估测

为探讨应用无人机多光谱技术估算矮林芳樟(Cinnamomum camphora(Linn.)Presl)光合参数的有效分析模型和方法,本研究以矮林芳樟为研究对象,通过无人机搭载的多光谱相机获取其冠层六波段光谱反射率,同步测量其净光合速率(Pn)、胞间二氧化碳浓度(Ci)、气孔导度(Gs)和蒸腾速率(Tr)4种光合参数,采用最佳指数因子(OIF)筛选光谱反射率和植被指数的组合作为自变量,分别采用偏最小二乘法(Partial least squares method,PLS)、反向传播神经网络(Back propagation neural network,BPNN)和随机森林(Random forest,RF)构建自变量与光合参数的估算模型,并分析比较各估算模型的精度。结果显示:矮林芳樟光合参数与叶片红边波段2(中心波长750 nm)和近红外波段(中心波长840 nm)反射率有密切关系;红边波段2、增强型植被指数2(EVI2)、红边叶绿素指数(CIrededge)组合的OIF值最大,为0.0126,可作为模型自变量的最佳组合;Pn、Ci、Gs、Tr 4种光合参数的最优模型均为BPNN,其建模集决定系数R^(2)分别为0.85、0.81、0.80、0.82,均方根误差(RMSE)分别为0.85μmol/(m^(2)·s)、16.23μmol/mol、0.03 mol/(m^(2)·s)、0.37 mmol/(m^(2)·s),相对分析误差(RPD)分别为2.59、2.33、2.28、2.37;验证集R^(2)为0.81、0.73、0.83、0.76,RMSE为1.46μmol/(m^(2)·s)、18.37μmol/mol、0.03 mol/(m^(2)·s)、0.67 mmol/(m^(2)·s),RPD为1.39、1.86、2.67、1.20。研究结果可为无人机多光谱遥感矮林芳樟光合参数估测提供理论依据,为快速监测大面积经济植物生长状况提供技术支撑。

煤滞尘对叶片反射光谱与植被指数的影响与定量分析

我国煤炭资源多集中在干旱少雨的北方地区,露天开采和运输等过程极易引起煤粉尘扩散和污染。粉尘扩散后其中一部分在重力作用下沉降覆盖到周边的植被上,导致植被降尘现象普遍。在利用遥感手段进行植被监测时,降尘效应会影响植被光谱的纯净性,使遥感器所获取的信号为植被与降尘的混合光谱信号,从而严重影响植被定量遥感精度。为定量研究植被遥感中煤尘的滞尘效应,开展了叶面滞尘光谱测量实验,探究了光谱和植被指数的变化规律;在此基础上,利用含有红边波段的Sentinel-2A遥感影像,在内蒙古霍林河露天矿区分别选择煤尘影响区与对照区两个区域进行植被指数对比,用来验证地面光谱测量实验结果。结果表明,随着滞尘量(0~36 g·m^(-2))的增加,叶面煤尘会使叶片的反射率整体逐渐降低,叶片光谱波峰处(560,720,860,1 680和2 220 nm)的反射率变化幅度明显高于波谷处(445,681和1 940 nm);随着滞尘量的增加,归一化差异植被指数(NDVI)、简单比值指数(SR_(705))和归一化差异指数(ND_(705))明显下降,而中分辨率成像光谱仪陆地叶绿素指数(MTCI)、改进型简单比值指数mSR_(705)(modified simple ratio)和改进型归一化差异指数(mND_(705))基本保持不变,表现出抗煤尘特性,445 nm处反射率和681 nm处反射率对指数起到了重要作用。利用霍林河露天煤矿区的Sentinel-2A遥感影像计算上述指数,将煤尘影响区与对照区比较,MTCI、 mSR_(705)和mND_(705)等指数表现了抗煤尘特性,验证了地面实验的结果。该研究为煤尘污染区域的植被遥感奠定了一定基础,对保证植被遥感反演精度具有积极意义。

Cultivar,Nitrogen and Irrigation Influence on Grain Quality and Its Forecasting Methods by In situ Reflected Spectrum of Winter Wheat

Field experiments were conducted to examine the influence factors of cultivar, nitrogen application and irrigation on grain protein content, gluten content and grain hardness in three winter wheat cultivars under four levels of nitrogen and irrigation treatments. Firstly, the influence of cultivars and environment factors on grain quality were studied, the effective factors were cultivars, irrigation, fertilization, etc. Secondly, total nitrogen content around winter wheat anthesis stage was proved to be significantly correlative with grain protein content, and spectral vegetation index significantly correlated to total nitrogen content around anthesis stage were the potential indicators for grain protein content. Accumulation of total nitrogen content and its transfer to grain is the physical link to produce the final grain protein, and total nitrogen content at anthesis stage was proved to be an indicator of final grain protein content. The selected normalized photochemical reflectance index (NPRI) was proved to be able to predict grain protein content on the close correlation between the ratio of total carotenoid to chlorophyll a and total nitrogen content. The method contributes towards developing optimal procedures for predicting wheat grain quality through analysis of their canopy reflected spectrum at anthesis stage. Regression equations were established to forecast grain protein and dry gluten content by total nitrogen content at anthesis stage, so it is feasible for forecasting grain quality by establishing correlation equations between biochemical constitutes and canopy reflected spectrum.

基于无人机可见光及多光谱数据的林草覆盖率提取方法研究

为了高效、准确地监测生产建设项目林草覆盖率指标,在山东省东营市建立典型样区,采用无人机搭载相同光谱分辨率的可见光和多光谱相机分别获取可见光、多光谱影像,建立16种植被指数(多光谱8种、可见光8种)。采用阈值法、支持向量机法计算林草覆盖率,并用混淆矩阵对结果精度进行对比,筛选出最优植被指数和分类方法。研究表明:1)8种多光谱植被指数和3种可见光植被指数识别精度>90%,Kappa系数>0.90,以上11种植被指数可满足实际水土保持监测需求。2)多光谱植被指数提取植被信息分类方法中,GRVI、SAVI、GNDVI、NDRE可用支持向量机法,RENDVI、EVI2、NDVI、OSAVI可用阈值法,可见光植被指数R、G、EXG可用阈值法。3)在正常状况下,多光谱和可见光植被指数获得较好的植被信息识别效果,但在有阴影存在情况下,单波段可见光R、G有错分现象。4)多光谱植被指数相比于可见光植被指数,具有更好的适用性和稳定性。

血流阻力指数在乳腺肿瘤良恶性鉴别诊断中的价值

目的:通过多普勒超声测得乳腺肿瘤血流阻力指数(RI),分析RI与乳腺肿瘤良恶性之间的关系。方法:选取2022年4-12月在我院行乳腺肿瘤手术并有病理结果的患者100例作为研究对象。100例患者均在术前彩超肿物定位检查中测得RI值,并在测量过程中,采取相应的手法和技巧,力求降低RI测值的人为变动因素,从而分析RI指标与乳腺肿瘤良恶性之间的关系并观察是否有更为准确的RI预测标准。结果:100例有手术病理结果的乳腺肿瘤患者中,恶性51例,良性49例;经ROC曲线统计分析,AUC(ROC曲线下方的面积)为0.87,RI>0.70为诊断标准,以该值为参考诊断乳腺癌的准确性为81%,灵敏度为82.4%、特异度为79.6%。结论:RI测量对乳腺肿瘤良恶性的鉴别诊断有一定的价值。乳腺肿瘤良恶性的鉴别诊断中,典型的肿块超声二维图像已有不少特征性的表现,诊断并不困难,但对于形态学改变并不突出、鉴别有困难的肿块,如恶变早期的病灶,RI值的测量则可以增加诊断筹码,为临床提供更接近真相的结果。

2000—2020年湖南省耕地坡谱演变规律研究

耕地是粮食生产的根基。文章利用土地利用数据和数字高程数据,结合坡谱分析方法,构建了耕地上山指数,分析了2000—2020年耕地坡谱在省和区域2个尺度上的变化规律以及影响耕地坡度变化的因素。结果显示:(1)2000—2020年时间段内,湖南省耕地的平均坡度增加了0.09°,高坡度(10°以上)地区耕地面积比例增加了0.68%,湖南省耕地逐渐向高坡度地区发展。(2)在区域尺度,经济相对发达的长株潭地区和地形较复杂的大湘西地区,耕地上山现象明显;经济较发达、以平原为主的洞庭湖地区,耕地上山现象不明显;湘南地区受到地形限制和经济快速发展双重影响,耕地上山程度仅次于长株潭地区。(3)退耕还林、非农建设、土地综合整治是影响耕地坡度变化的主要因素,可通过积极稳妥开展退耕还林工作、合理引导建设用地上山、严控新增耕地管理等措施,来减缓耕地在高坡度区域增加趋势,即减缓耕地上山现象。

典型伪装材料高光谱特征及识别方法研究

针对某些特定环境下,伪装目标和背景目标出现的“异物同谱”现象,传统的可见光及多光谱遥感伪装识别存在局限性,为此,将高光谱应用到典型伪装材料的特征分析与识别。以北方地区常用丛林迷彩伪装网为研究对象,利用SVC HR1024光谱仪获取其不同浸水时间的可见光-近红外光谱,通过光谱相似性度量和包络线去除处理,分析揭示不同浸水条件下伪装网和北方典型植被光谱特征和敏感波段,并基于近红外波段构建光谱比值指数RCI,用于识别绿色植被环境中的伪装目标,最后通过高光谱成像实验获取仿真伪装环境高光谱图像,并利用高光谱图像对识别效果进行验证。结果显示:(1)不同浸水时间的丛林迷彩伪装网的光谱曲线基本形态相似,且反射率随浸水时间的增加而整体呈下降趋势;1900 nm波段是伪装网反射光谱对含水量响应最为明显的波段,其光谱特征会因浸水处理而相似于植被,相似度从0.895提高到了0.939。(2)丛林迷彩伪装网和植被在可见光波段的相似度较高,光谱波动情况相似,但在近红外波段光谱特征差异明显。通过包络线统去除分析得出970,1190和1440 nm波段附近处是丛林迷彩伪装网识别的敏感波段,且基于迷彩伪装网和各植被在900~1900 nm波段范围内存在的2处明显反射率斜率的差异,构建了伪装网识别特征指数RCI_(1)(R_(1190)/R_(1270))和RCI_(2)(R_(1270)/R_(1440))。(3)基于RCI指数构建决策树分类模型,可以快速有效的将伪装目标从绿色植被背景中提取出来。实验结果表明,基于RCI指数对伪装目标区域进行识别提取,所得结果在形态和大小上与原影像具有较好地一致性,识别精度可达95%,表明该指数对于伪装目标具有较好的识别效果。

基于光谱和色度信息的猪肉肉色研究

本试验旨在研究不同部位猪肉的光谱特征及其与肉色之间的关系。利用ASD-2000光谱仪以及CR-400色差仪分别测定不同部位猪肉的光谱数据和对应的肉色值,形成不同部位猪肉的特征光谱。通过随机森林、最大互信息数和最佳指数因子,选取出反映肉色差异最大的473和1078 nm波段,利用该波段组合,提出了肉色比值指数(PCRI),同时分析了PCRI与化学色度和褐化指数之间的相关性。结果表明,五花肉光谱特征较易区分,而通脊和腿肉的光谱特征略有相似,但利用PCRI可以有效区分二者。通脊和腿肉的PCRI与化学色度呈显著负相关(P<0.05),通脊的PCRI与褐化指数呈显著负相关(P<0.05)。综上所述,本文基于不同部位猪肉的光谱数据得到了其光谱特征,并提取出PCRI,且猪肉的PCRI与化学色度和褐化指数呈显著负相关。