Adaptive Density-Based Spatial Clustering of Applications with Noise(ADBSCAN)for Clusters of Different Densities

Finding clusters based on density represents a significant class of clustering algorithms.These methods can discover clusters of various shapes and sizes.The most studied algorithm in this class is theDensity-Based Spatial Clustering of Applications with Noise(DBSCAN).It identifies clusters by grouping the densely connected objects into one group and discarding the noise objects.It requires two input parameters:epsilon(fixed neighborhood radius)and MinPts(the lowest number of objects in epsilon).However,it can’t handle clusters of various densities since it uses a global value for epsilon.This article proposes an adaptation of the DBSCAN method so it can discover clusters of varied densities besides reducing the required number of input parameters to only one.Only user input in the proposed method is the MinPts.Epsilon on the other hand,is computed automatically based on statistical information of the dataset.The proposed method finds the core distance for each object in the dataset,takes the average of these distances as the first value of epsilon,and finds the clusters satisfying this density level.The remaining unclustered objects will be clustered using a new value of epsilon that equals the average core distances of unclustered objects.This process continues until all objects have been clustered or the remaining unclustered objects are less than 0.006 of the dataset’s size.The proposed method requires MinPts only as an input parameter because epsilon is computed from data.Benchmark datasets were used to evaluate the effectiveness of the proposed method that produced promising results.Practical experiments demonstrate that the outstanding ability of the proposed method to detect clusters of different densities even if there is no separation between them.The accuracy of the method ranges from 92%to 100%for the experimented datasets.

Fully Automated Density-Based Clustering Method

Cluster analysis is a crucial technique in unsupervised machine learning,pattern recognition,and data analysis.However,current clustering algorithms suffer from the need for manual determination of parameter values,low accuracy,and inconsistent performance concerning data size and structure.To address these challenges,a novel clustering algorithm called the fully automated density-based clustering method(FADBC)is proposed.The FADBC method consists of two stages:parameter selection and cluster extraction.In the first stage,a proposed method extracts optimal parameters for the dataset,including the epsilon size and a minimum number of points thresholds.These parameters are then used in a density-based technique to scan each point in the dataset and evaluate neighborhood densities to find clusters.The proposed method was evaluated on different benchmark datasets andmetrics,and the experimental results demonstrate its competitive performance without requiring manual inputs.The results show that the FADBC method outperforms well-known clustering methods such as the agglomerative hierarchical method,k-means,spectral clustering,DBSCAN,FCDCSD,Gaussian mixtures,and density-based spatial clustering methods.It can handle any kind of data set well and perform excellently.

Density-based trajectory outlier detection algorithm

With the development of global position system（GPS）,wireless technology and location aware services,it is possible to collect a large quantity of trajectory data.In the field of data mining for moving objects,the problem of anomaly detection is a hot topic.Based on the development of anomalous trajectory detection of moving objects,this paper introduces the classical trajectory outlier detection（TRAOD） algorithm,and then proposes a density-based trajectory outlier detection（DBTOD） algorithm,which compensates the disadvantages of the TRAOD algorithm that it is unable to detect anomalous defects when the trajectory is local and dense.The results of employing the proposed algorithm to Elk1993 and Deer1995 datasets are also presented,which show the effectiveness of the algorithm.

Density-based rough set model for hesitant node clustering in overlapping community detection

Overlapping community detection in a network is a challenging issue which attracts lots of attention in recent years.A notion of hesitant node（HN） is proposed. An HN contacts with multiple communities while the communications are not strong or even accidental, thus the HN holds an implicit community structure.However, HNs are not rare in the real world network. It is important to identify them because they can be efficient hubs which form the overlapping portions of communities or simple attached nodes to some communities. Current approaches have difficulties in identifying and clustering HNs. A density-based rough set model（DBRSM） is proposed by combining the virtue of densitybased algorithms and rough set models. It incorporates the macro perspective of the community structure of the whole network and the micro perspective of the local information held by HNs, which would facilitate the further ＂growth＂ of HNs in community. We offer a theoretical support for this model from the point of strength of the trust path. The experiments on the real-world and synthetic datasets show the practical significance of analyzing and clustering the HNs based on DBRSM. Besides, the clustering based on DBRSM promotes the modularity optimization.

LeaDen-Stream: A Leader Density-Based Clustering Algorithm over Evolving Data Stream

Clustering evolving data streams is important to be performed in a limited time with a reasonable quality. The existing micro clustering based methods do not consider the distribution of data points inside the micro cluster. We propose LeaDen-Stream (Leader Density-based clustering algorithm over evolving data Stream), a density-based clustering algorithm using leader clustering. The algorithm is based on a two-phase clustering. The online phase selects the proper mini-micro or micro-cluster leaders based on the distribution of data points in the micro clusters. Then, the leader centers are sent to the offline phase to form final clusters. In LeaDen-Stream, by carefully choosing between two kinds of micro leaders, we decrease time complexity of the clustering while maintaining the cluster quality. A pruning strategy is also used to filter out real data from noise by introducing dense and sparse mini-micro and micro-cluster leaders. Our performance study over a number of real and synthetic data sets demonstrates the effectiveness and efficiency of our method.

Multimode Process Monitoring Based on the Density-Based Support Vector Data Description

Complex industry processes often need multiple operation modes to meet the change of production conditions. In the same mode,there are discrete samples belonging to this mode. Therefore,it is important to consider the samples which are sparse in the mode.To solve this issue,a new approach called density-based support vector data description( DBSVDD) is proposed. In this article,an algorithm using Gaussian mixture model( GMM) with the DBSVDD technique is proposed for process monitoring. The GMM method is used to obtain the center of each mode and determine the number of the modes. Considering the complexity of the data distribution and discrete samples in monitoring process,the DBSVDD is utilized for process monitoring. Finally,the validity and effectiveness of the DBSVDD method are illustrated through the Tennessee Eastman( TE) process.

Three-dimensional(3D)parametric measurements of individual gravels in the Gobi region using point cloud technique

Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed dunes.Its presence significantly influences the movement of sand and dust.However,the complex origins and diverse materials constituting the Gobi result in notable differences in saltation processes across various Gobi surfaces.It is challenging to describe these processes according to a uniform morphology.Therefore,it becomes imperative to articulate surface characteristics through parameters such as the three-dimensional(3D)size and shape of gravel.Collecting morphology information for Gobi gravels is essential for studying its genesis and sand saltation.To enhance the efficiency and information yield of gravel parameter measurements,this study conducted field experiments in the Gobi region across Dunhuang City,Guazhou County,and Yumen City(administrated by Jiuquan City),Gansu Province,China in March 2023.A research framework and methodology for measuring 3D parameters of gravel using point cloud were developed,alongside improved calculation formulas for 3D parameters including gravel grain size,volume,flatness,roundness,sphericity,and equivalent grain size.Leveraging multi-view geometry technology for 3D reconstruction allowed for establishing an optimal data acquisition scheme characterized by high point cloud reconstruction efficiency and clear quality.Additionally,the proposed methodology incorporated point cloud clustering,segmentation,and filtering techniques to isolate individual gravel point clouds.Advanced point cloud algorithms,including the Oriented Bounding Box(OBB),point cloud slicing method,and point cloud triangulation,were then deployed to calculate the 3D parameters of individual gravels.These systematic processes allow precise and detailed characterization of individual gravels.For gravel grain size and volume,the correlation coefficients between point cloud and manual measurements all exceeded 0.9000,confirming the feasibility of the proposed methodology for measuring 3D parameters of individual gravels.The proposed workflow yields accurate calculations of relevant parameters for Gobi gravels,providing essential data support for subsequent studies on Gobi environments.

Combination of density-clustering and supervised classification for event identification in single-molecule force spectroscopy data

Single-molecule force spectroscopy(SMFS)measurements of the dynamics of biomolecules typically require identifying massive events and states from large data sets,such as extracting rupture forces from force-extension curves(FECs)in pulling experiments and identifying states from extension-time trajectories(ETTs)in force-clamp experiments.The former is often accomplished manually and hence is time-consuming and laborious while the latter is always impeded by the presence of baseline drift.In this study,we attempt to accurately and automatically identify the events and states from SMFS experiments with a machine learning approach,which combines clustering and classification for event identification of SMFS(ACCESS).As demonstrated by analysis of a series of data sets,ACCESS can extract the rupture forces from FECs containing multiple unfolding steps and classify the rupture forces into the corresponding conformational transitions.Moreover,ACCESS successfully identifies the unfolded and folded states even though the ETTs display severe nonmonotonic baseline drift.Besides,ACCESS is straightforward in use as it requires only three easy-to-interpret parameters.As such,we anticipate that ACCESS will be a useful,easy-to-implement and high-performance tool for event and state identification across a range of single-molecule experiments.

Spatial Distribution Pattern and Influencing Factors of Physical Bookstores of Large Cities:A Case Study of Three National Central Cities in Western China

As cultural facilities,physical bookstore is an important part of urban infrastructure.Influenced by the development of social economy and the internet,physical bookstores also have become a combination of cultural space and tourism experience.In this case,it is necessary to explore the spatial characteristics and influencing factors of physical bookstores.This study uses Density-Based Spatial Clustering of Applications with Noise(DBSCAN),spatial analysis and geographical detectors to calculate the spatial distribution pattern and factors influencing physical bookstores in national central cities/municipality(hereafter using cities)in western China.Based on spatial data,population density,road density and other data,this study constructed a data set of the influencing factors of physical bookstores,consisting of 11 factors along 6 dimensions for 3 national central cities in western China.The results are as follows:first,the spatial distribution pattern of physical bookstores in Xi’an,Chengdu,and Chongqing is unbalanced.The spatial distribution of physical bookstores in Xi’an and Chongqing is from southwest to northeast and are relatively clustered,while those in Chengdu are relatively discrete.Second,the spatial distribution pattern of physical bookstores has been formed under the influence of different factors.The intensity and significance of influencing factors differ in the case cities.However,in general,the social factor,business factor,the density of research facilities,tourism factor and road density are the main driving factors in the three cities.There is a synergistic relationship between public libraries and physical bookstores.Third,the explanatory power becomes stronger after the interaction between various factors.In Xi’an and Chengdu,the density of communities and the density of research facilities have stronger explanatory power for the dependent variable after interacting with other factors.However,in Chongqing,the traffic factors have stronger explanatory power for the dependent variable after interacting with other factors.The results could provide a practical reference for the sustainable development of physical bookstores and encourage a love of reading among the public.

A Novel Ultra Short-Term Load Forecasting Method for Regional Electric Vehicle Charging Load Using Charging Pile Usage Degree

Electric vehicle(EV)charging load is greatly affected by many traffic factors,such as road congestion.Accurate ultra short-term load forecasting(STLF)results for regional EV charging load are important to the scheduling plan of regional charging load,which can be derived to realize the optimal vehicle to grid benefit.In this paper,a regional-level EV ultra STLF method is proposed and discussed.The usage degree of all charging piles is firstly defined by us based on the usage frequency of charging piles,and then constructed by our collected EV charging transactiondata in thefield.Secondly,these usagedegrees are combinedwithhistorical charging loadvalues toform the inputmatrix for the deep learning based load predictionmodel.Finally,long short-termmemory(LSTM)neural network is used to construct EV charging load forecastingmodel,which is trained by the formed inputmatrix.The comparison experiment proves that the proposed method in this paper has higher prediction accuracy compared with traditionalmethods.In addition,load characteristic index for the fluctuation of adjacent day load and adjacent week load are proposed by us,and these fluctuation factors are used to assess the prediction accuracy of the EV charging load,together with the mean absolute percentage error(MAPE).

基于公理设计与模糊树图的集成式模块划分方法

提出了一种公理设计和模糊树图相结合的集成式模块划分方法。首先采用公理设计的功能域-物理域的映射变换框架进行产品的逐级分解,在分解得到的设计矩阵均为对角阵的情况下,分解得到的子结构满足了功能和结构的独立性,可单独作为一个模块,完成模块划分。若得到的设计矩阵为三角阵或者满矩阵,则对分解得到的子结构进行功能和结构相关度的分析,采用模糊树图聚类法将子结构聚类为模块。通过实例验证了该方法的有效性和合理性。

基于DBSCAN算法的郑洛地区史前聚落遗址聚类分析

为了解决判别聚落群过于依赖考古专家人工划分的问题,以郑洛地区新石器时代聚落遗址为例,采用基于密度的DBSCAN(density-based spatial clustering of applications with noise)算法对聚落遗址进行空间聚类研究。通过对郑洛地区四个文化时期聚落遗址的分布分析,发现郑洛地区的主体聚落群从研究区东部的嵩山以南地区,转移到郑洛地区中部的伊洛河流域,并且在伊洛河流域长期定居下来,不断发展扩大;大型聚落遗址主要分布在主体聚落群里,除了裴李岗文化时期部分大型聚落较孤立;从仰韶文化后期到龙山文化时期,聚落遗址分布呈主从式环状分布格局;大多数聚落群的走向都和河流分布一致。研究表明,利用DBSCAN算法进行聚落遗址聚类是可行的,通过聚类得到郑洛地区新石器时代四个文化时期聚落遗址的分布特征。

适用于海量负荷数据分类的高性能反向传播神经网络算法

负荷分类对于指导电网发用电规划与保证电网可靠运行具有重要意义。面向负荷数据海量化与复杂化趋势,传统负荷分类方法已无法满足用电大数据分析要求。首先,针对用户侧数据体量大、类型多、速度快等特点,在Spark平台上将反向传播神经网络(BPNN)算法并行化,实现对海量负荷数据的高效分类。然后,通过对训练样本抽样分块以降低各网络学习时间,针对分布式后BPNN基分类器由于学习样本缺失潜在的准确度下降问题,采用集成学习予以改善。并通过BPNN学习不同训练样本块构建差异化基分类器,对基分类结果多数投票得到最终分类结果。另外,提供了一种基于K-means和K-medoids聚类的负荷数据训练样本选取方法。算例表明所提方法既能对负荷曲线有效分类,又能大幅提高海量数据的处理效率。

基于SURF的高密度人群计数方法

为了解决在高密度人流或视场开阔环境下人群计数准确率低的问题,提出一种基于SURF的高密度人群计数方法.首先采用最小生成树改进了传统的基于密度的聚类算法,使其最小搜索域自适应聚类数据的分布;在此基础上实现运动人群的SURF特征点分类,并以此构建运动人群的特征向量,用支持向量回归机实现了对高密度人群的数量统计.实验结果表明,该方法对高密度人群的计数有较高的准确率和鲁棒性.

加权空间函数优化FCM的SAR图像分割

传统模糊c-均值聚类算法没有考虑图像像素空间信息特征,在应用于合成孔径雷达图像分割时,由于合成孔径雷达图像中斑点噪声的影响,通常不能得到正确的分割结果.基于此问题提出加权空间隶属度和加权空间函数并应用于c-均值聚类算法,加权空间隶属度是多尺度条件下空间各相邻像素的位置和强度信息的加权隶属度值,加权空间函数中各加权空间隶属度的影响系数由自适应遗传算法优化,最终的隶属度值由加权空间函数修正.由于在这种聚类过程中融入了优化的空间信息,因此弱化了斑点噪声的影响,提高了分割精度.这种算法应用于实际合成孔径雷达图像分割实验,结果表明此算法对初始分类结果不敏感,具有较强的抗噪性能,改善了SAR图像的分割结果.

逆向工程中点云孔洞修补技术研究

对于散乱点云模型上的大面积、跨面孔洞,逆向软件往往难以修补。为了提高孔洞修补精度、获得完整的点云模型,提出了对手受惩罚竞争学习算法(Rival penalized competitive learning,RPCL)和模糊C均值聚类算法(Fuzzy C-means,FCM)相结合的综合改进径向基函数神经网络(RBF)算法,建立了基于改进算法的点云孔洞修补模型,并以挖掘机斗齿和汽车模型为研究对象,利用RPCL-FCM-RBF联合算法对不同特征的点云孔洞进行了修补研究。结果表明,该算法在很大程度上提高了点云孔洞的修补精度,其补洞效果远优于逆向软件。而且,较之传统的RBF神经网络,该方法所建模型具有更高的预测精度、能够有效地调整洞口缺失数据、实现点云孔洞的精确修复,实用性强。

一种基于距离的聚类和孤立点检测算法

提出了一种基于距离的聚类和孤立点检测算法(DBCOD),根据距离阈值对数据点进行聚类,在聚类过程中记录每个数据点的密度,并根据密度阈值确定数据点是否为孤立点.实验结果表明,该算法不仅能够对数据集进行正确的聚类,可以发现任意形状的聚类,算法执行效率优于DBSCAN,具有对噪音数据、数据输入顺序不敏感等优点,同时还能有效地进行孤立点检测.

基于RBF神经网络的客户分类模型

运用径向基函数(RBF)神经网络和K均值聚类算法建立了客户价值分类模型,并用最小二乘法调整RBF的权值.仿真结果证明了该方法的有效性.

广义径向基函数神经网络在热误差建模中的应用

针对现有的热误差建模方法建模效率低,模型预测精度不理想等问题,提出了广义径向基函数神经网络(RBF)建模方法并将其应用于数控机床热误差建模中。讨论了采用广义RBF神经网络进行热误差建模的原理及步骤。以数控导轨磨床主轴箱系统为例,布置了12个主轴热误差的关键温度测点,测得了2组独立的主轴箱系统热误差数据。将测得的数据分别用于建立主轴箱系统热误差广义RBF神经网络预报模型和验证模型的准确性。研究结果表明,热误差广义RBF神经网络模型具有预测精度高及泛化能力强的优点;与传统的RBF神经网络建模方法相比,提出的广义RBF神经网络建模方法建模效率更高,模型鲁棒性及预测性能更好,是一种可以用于数控机床热误差实时补偿的有效建模方法。

Adam优化的CNN超分辨率重建

为了使单帧图像在不同放大倍数的条件下进行超分辨率重建能得到较好的效果,提出了一种Adam优化的卷积神经网络(convolutional neural network,CNN)超分辨率重建方法。该方法首先使用ISODATA(iterative selforganizing data analysis)聚类算法对训练的图像集进行分类处理,然后在Adam优化的卷积神经网络中对输入图像进行特征提取和非线性映射得到特征映射图,最后在Adam优化的卷积神经网络中对特征映射图进行反卷积重建得到多尺度放大的重建图像。通过实验验证使用该方法在不同放大倍数条件下的重构效果优于传统算法,在视觉效果上有较好的表现。