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51.
最近邻法是一种传统的基于实例的分类方法,将最近邻法应用到水质综合评价中,建立了最近邻模型,利用三峡库区城市江段13个监测断面的检测数据进行评价,评价结果表明,水体尚清洁,综合污染程度不严重.为验证最近邻法评价结果的有效性,对模糊综合评价法和最近邻法的评价结果进行比较,得到了较好的效果,具有推广价值. 相似文献
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53.
The Neighbor Cell Deposited Energy Ratio(NCDER) is a new method that is proposed to reconstruct incidence position in a single layer for a 3-dimensional imaging electromagnetic calorimeter(ECAL).This method was applied to reconstruct the ECAL test beam data for the Alpha Magnetic Spectrometer-02(AMS-02).The results show that this method can achieve an angular resolution of 7.36±0.08°/E~(1/2)(?)0.28±0.02o in the determination of the photon's direction,which is much more precise than that obtained with the commonly-adopted Center of Gravity(COG) method(8.4±0.1°/E~(1/2)(?)0.8±0.3o).Furthermore,since it uses only the properties of electromagnetic showers,this new method could also be used for other type of fine grain sampling calorimeters. 相似文献
54.
恒星光谱参数自动测量中不同模板匹配度量方法比较 总被引：1，自引：0，他引：1
模板匹配方法是恒星光谱参数自动测量中常用的方法之一。对经常使用的三种模板匹配算法：K-最近邻算法(KNN)、卡方最小化算法和光谱相似度算法测量恒星光谱参数结果进行比较。首先对光谱进行连续谱归一化及流量归一化,然后对三种算法测量恒星光谱参数的结果进行比较。对SDSS DR8大样本数据的实验表明,光谱相似度算法在测量恒星光谱参数中有相对优势。 相似文献
55.
Danjun Huang & Dan Bao 《数学研究》2023,56(2):206-218
For a given simple graph $G = (V(G),E(G)),$ a proper total-$k$-coloring $c :V(G)∪E(G)→ {1,2,...,k}$ is neighbor sum distinguishing if $f(u)≠ f(v)$ for each edge $uv ∈ E(G),$ where $f(v) = sum_{wv∈E(G)} c(wv)+c(v).$ The smallest integer $k$ in such a coloring of $G$ is the neighbor sum distinguishing total chromatic number, denoted by $chi^{''}_{sum} (G).$ It has been conjectured that $chi ^{''}_{sum} (G) ≤ ∆(G)+3$ for any simple graph $G.$ Let $mad (G)=max{ frac{2|E(H)|}{ |V(H)|} :H⊆G}$ be the maximum average degree of $G.$ In this paper, byusing the famous Combinatorial Nullstellensatz, we prove $chi^{''} _{sum}(G) ≤ max{9,∆(G)+2}$ for any graph $G$ with $mad (G)<4.$ Furthermore, we characterize the neighbor sum distinguishing total chromatic number for every graph $G$ with $mad (G)<4$ and $∆(G)≥8.$ 相似文献
56.
A graph is IC-planar if it admits a drawing in the plane such that each edge is crossed at most once and two crossed edges share no common end-vertex.A proper total-k-coloring of G is called neighbor sum distinguishing if∑_c(u)≠∑_c(v)for each edge uv∈E(G),where∑_c(v)denote the sum of the color of a vertex v and the colors of edges incident with v.The least number k needed for such a total coloring of G,denoted byχ∑\"is the neighbor sum distinguishing total chromatic number.Pilsniak and Wozniak conjecturedχ∑\"(G)≤Δ(G)+3 for any simple graph with maximum degreeΔ(G).By using the famous Combinatorial Nullstellensatz,we prove that above conjecture holds for any triangle free IC-planar graph with△(G)≥7.Moreover,it holds for any triangle free planar graph withΔ(G)≥6. 相似文献
57.
《Journal of Chemometrics》2018,32(2)
With the increasing availability of digital imaging devices, colorimetric sensor arrays are rapidly becoming a simple, yet effective tool for the identification and quantification of various analytes. Colorimetric arrays utilize colorimetric data from many colorimetric sensors, with the multidimensional nature of the resulting data necessitating the use of chemometric analysis. Herein, an 8 sensor colorimetric array was used to analyze select acid and basic samples (0.5 – 10 M) to determine which chemometric methods are best suited for classification quantification of analytes within clusters. PCA, HCA, and LDA were used to visualize the data set. All three methods showed well‐separated clusters for each of the acid or base analytes and moderate separation between analyte concentrations, indicating that the sensor array can be used to identify and quantify samples. Furthermore, PCA could be used to determine which sensors showed the most effective analyte identification. LDA, KNN, and HQI were used for identification of analyte and concentration. HQI and KNN could be used to correctly identify the analytes in all cases, while LDA correctly identified 95 of 96 analytes correctly. Additional studies demonstrated that controlling for solvent and image effects was unnecessary for all chemometric methods utilized in this study. 相似文献
58.
Kurt Varmuza Peter Filzmoser Nicolas Fray Hervé Cottin Sihane Merouane Oliver Stenzel John Paquette Jochen Kissel Christelle Briois Donia Baklouti Anaïs Bardyn Sandra Siljeström Johan Silén Martin Hilchenbach 《Journal of Chemometrics》2020,34(4):e3218
The instrument COSIMA (COmetary Secondary Ion Mass Analyzer) onboard of the European Space Agency mission Rosetta collected and analyzed dust particles in the neighborhood of comet 67P/Churyumov-Gerasimenko. The chemical composition of the particle surfaces was characterized by time-of-flight secondary ion mass spectrometry. A set of 2213 spectra has been selected, and relative abundances for CH-containing positive ions as well as positive elemental ions define a set of multivariate data with nine variables. Evaluation by complementary chemometric techniques shows different compositions of sample groups collected during two periods of the mission. The first period was August to November 2014 (far from the Sun); the second period was January 2015 to February 2016 (nearer to the Sun). The applied data evaluation methods consider the compositional nature of the mass spectral data and comprise robust principal component analysis as well as classification with discriminant partial least squares regression, k-nearest neighbor search, and random forest decision trees. The results indicate a high importance of the relative abundances of the secondary ions C+ and Fe+ for the group separation and demonstrate an enhanced content of carbon-containing substances in samples collected in the period with smaller distances to the Sun. 相似文献
59.
In this work, we use the concept of distance between self-dual codes, which generalizes the concept of a neighbor for self-dual codes. Using the k-neighbors, we are able to construct extremal binary self-dual codes of length 68 with new weight enumerators. We construct 143 extremal binary self-dual codes of length 68 with new weight enumerators including 42 codes with in their and 40 with in their . These examples are the first in the literature for these γ values. This completes the theoretical list of possible values for γ in . 相似文献
60.
采用固相烧结法制备了Eu3+掺杂的铌酸钠钾（KNN）陶瓷。用X射线粉末衍射仪、荧光光谱测试仪和LCR精确阻抗测试仪等对其结构、发光性能和介电性能进行表征。XRD结果显示样品为钙钛矿结构。荧光分析结果表明,致密度对KNN陶瓷材料发光性能有一定的影响,Eu3+掺杂量是影响其发光性能的重要因素。其中掺杂Eu摩尔分数为4%的样品在930℃焙烧后其发光最强,在396nm紫外光激发下,发射光谱最强峰在614nm,对应于Eu3+的5D0-7F2电偶极跃迁。样品经3kV/cm、110℃极化30min后进行压电性能检测,结果表明提高Eu3+掺杂量以及陶瓷的致密度,可改善压电性能。其中掺杂4%Eu的KNN压电常数D33最大为98pC/N,在1kHz、100℃时,介电常数最小为217,介电损耗tanθ=0.199,且仍然保持较高的居里温度Tc=426℃。 相似文献