Real-Time Spreading Thickness Monitoring of High-core Rockfill Dam Based on K-nearest Neighbor Algorithm

During the storehouse surface rolling construction of a core rockfilldam, the spreading thickness of dam face is an important factor that affects the construction quality of the dam storehouse' rolling surface and the overallquality of the entire dam. Currently, the method used to monitor and controlspreading thickness during the dam construction process is artificialsampling check after spreading, which makes it difficult to monitor the entire dam storehouse surface. In this paper, we present an in-depth study based on real-time monitoring and controltheory of storehouse surface rolling construction and obtain the rolling compaction thickness by analyzing the construction track of the rolling machine. Comparatively, the traditionalmethod can only analyze the rolling thickness of the dam storehouse surface after it has been compacted and cannot determine the thickness of the dam storehouse surface in realtime. To solve these problems, our system monitors the construction progress of the leveling machine and employs a real-time spreading thickness monitoring modelbased on the K-nearest neighbor algorithm. Taking the LHK core rockfilldam in Southwest China as an example, we performed real-time monitoring for the spreading thickness and conducted real-time interactive queries regarding the spreading thickness. This approach provides a new method for controlling the spreading thickness of the core rockfilldam storehouse surface.

Enhancing Cancer Classification through a Hybrid Bio-Inspired Evolutionary Algorithm for Biomarker Gene Selection

In this study,our aim is to address the problem of gene selection by proposing a hybrid bio-inspired evolutionary algorithm that combines Grey Wolf Optimization(GWO)with Harris Hawks Optimization(HHO)for feature selection.Themotivation for utilizingGWOandHHOstems fromtheir bio-inspired nature and their demonstrated success in optimization problems.We aimto leverage the strengths of these algorithms to enhance the effectiveness of feature selection in microarray-based cancer classification.We selected leave-one-out cross-validation(LOOCV)to evaluate the performance of both two widely used classifiers,k-nearest neighbors(KNN)and support vector machine(SVM),on high-dimensional cancer microarray data.The proposed method is extensively tested on six publicly available cancer microarray datasets,and a comprehensive comparison with recently published methods is conducted.Our hybrid algorithm demonstrates its effectiveness in improving classification performance,Surpassing alternative approaches in terms of precision.The outcomes confirm the capability of our method to substantially improve both the precision and efficiency of cancer classification,thereby advancing the development ofmore efficient treatment strategies.The proposed hybridmethod offers a promising solution to the gene selection problem in microarray-based cancer classification.It improves the accuracy and efficiency of cancer diagnosis and treatment,and its superior performance compared to other methods highlights its potential applicability in realworld cancer classification tasks.By harnessing the complementary search mechanisms of GWO and HHO,we leverage their bio-inspired behavior to identify informative genes relevant to cancer diagnosis and treatment.

A Study of EM Algorithm as an Imputation Method: A Model-Based Simulation Study with Application to a Synthetic Compositional Data

Compositional data, such as relative information, is a crucial aspect of machine learning and other related fields. It is typically recorded as closed data or sums to a constant, like 100%. The statistical linear model is the most used technique for identifying hidden relationships between underlying random variables of interest. However, data quality is a significant challenge in machine learning, especially when missing data is present. The linear regression model is a commonly used statistical modeling technique used in various applications to find relationships between variables of interest. When estimating linear regression parameters which are useful for things like future prediction and partial effects analysis of independent variables, maximum likelihood estimation (MLE) is the method of choice. However, many datasets contain missing observations, which can lead to costly and time-consuming data recovery. To address this issue, the expectation-maximization (EM) algorithm has been suggested as a solution for situations including missing data. The EM algorithm repeatedly finds the best estimates of parameters in statistical models that depend on variables or data that have not been observed. This is called maximum likelihood or maximum a posteriori (MAP). Using the present estimate as input, the expectation (E) step constructs a log-likelihood function. Finding the parameters that maximize the anticipated log-likelihood, as determined in the E step, is the job of the maximization (M) phase. This study looked at how well the EM algorithm worked on a made-up compositional dataset with missing observations. It used both the robust least square version and ordinary least square regression techniques. The efficacy of the EM algorithm was compared with two alternative imputation techniques, k-Nearest Neighbor (k-NN) and mean imputation (), in terms of Aitchison distances and covariance.

A Memetic Algorithm With Competition for the Capacitated Green Vehicle Routing Problem

In this paper, a memetic algorithm with competition(MAC) is proposed to solve the capacitated green vehicle routing problem(CGVRP). Firstly, the permutation array called traveling salesman problem(TSP) route is used to encode the solution, and an effective decoding method to construct the CGVRP route is presented accordingly. Secondly, the k-nearest neighbor(k NN) based initialization is presented to take use of the location information of the customers. Thirdly, according to the characteristics of the CGVRP, the search operators in the variable neighborhood search(VNS) framework and the simulated annealing(SA) strategy are executed on the TSP route for all solutions. Moreover, the customer adjustment operator and the alternative fuel station(AFS) adjustment operator on the CGVRP route are executed for the elite solutions after competition. In addition, the crossover operator is employed to share information among different solutions. The effect of parameter setting is investigated using the Taguchi method of design-ofexperiment to suggest suitable values. Via numerical tests, it demonstrates the effectiveness of both the competitive search and the decoding method. Moreover, extensive comparative results show that the proposed algorithm is more effective and efficient than the existing methods in solving the CGVRP.

An Improved Whale Optimization Algorithm for Feature Selection

Whale optimization algorithm(WOA)is a new population-based meta-heuristic algorithm.WOA uses shrinking encircling mechanism,spiral rise,and random learning strategies to update whale’s positions.WOA has merit in terms of simple calculation and high computational accuracy,but its convergence speed is slow and it is easy to fall into the local optimal solution.In order to overcome the shortcomings,this paper integrates adaptive neighborhood and hybrid mutation strategies into whale optimization algorithms,designs the average distance from itself to other whales as an adaptive neighborhood radius,and chooses to learn from the optimal solution in the neighborhood instead of random learning strategies.The hybrid mutation strategy is used to enhance the ability of algorithm to jump out of the local optimal solution.A new whale optimization algorithm(HMNWOA)is proposed.The proposed algorithm inherits the global search capability of the original algorithm,enhances the exploitation ability,improves the quality of the population,and thus improves the convergence speed of the algorithm.A feature selection algorithm based on binary HMNWOA is proposed.Twelve standard datasets from UCI repository test the validity of the proposed algorithm for feature selection.The experimental results show that HMNWOA is very competitive compared to the other six popular feature selection methods in improving the classification accuracy and reducing the number of features,and ensures that HMNWOA has strong search ability in the search feature space.

Research on Initialization on EM Algorithm Based on Gaussian Mixture Model

The EM algorithm is a very popular maximum likelihood estimation method, the iterative algorithm for solving the maximum likelihood estimator when the observation data is the incomplete data, but also is very effective algorithm to estimate the finite mixture model parameters. However, EM algorithm can not guarantee to find the global optimal solution, and often easy to fall into local optimal solution, so it is sensitive to the determination of initial value to iteration. Traditional EM algorithm select the initial value at random, we propose an improved method of selection of initial value. First, we use the k-nearest-neighbor method to delete outliers. Second, use the k-means to initialize the EM algorithm. Compare this method with the original random initial value method, numerical experiments show that the parameter estimation effect of the initialization of the EM algorithm is significantly better than the effect of the original EM algorithm.

Condition Monitoring of Roller Bearing by K-star Classifier andK-nearest Neighborhood Classifier Using Sound Signal

Most of the machineries in small or large-scale industry have rotating elementsupported by bearings for rigid support and accurate movement. For proper functioning ofmachinery, condition monitoring of the bearing is very important. In present study soundsignal is used to continuously monitor bearing health as sound signals of rotatingmachineries carry dynamic information of components. There are numerous studies inliterature that are reporting superiority of vibration signal of bearing fault diagnosis.However, there are very few studies done using sound signal. The cost associated withcondition monitoring using sound signal (Microphone) is less than the cost of transducerused to acquire vibration signal (Accelerometer). This paper employs sound signal forcondition monitoring of roller bearing by K-star classifier and k-nearest neighborhoodclassifier. The statistical feature extraction is performed from acquired sound signals. Thentwo-layer feature selection is done using J48 decision tree algorithm and random treealgorithm. These selected features were classified using K-star classifier and k-nearestneighborhood classifier and parametric optimization is performed to achieve the maximumclassification accuracy. The classification results for both K-star classifier and k-nearestneighborhood classifier for condition monitoring of roller bearing using sound signals werecompared.

基于PCA+KNN和kernal-PCA+KNN算法的废旧纺织物鉴别

该研究采集了15类废旧纺织物的4 998张近红外谱图,以7∶3的比例分为训练集和验证集,并分别采用主成分分析(PCA)与核主成分分析(kernal-PCA)两种不同降维方法对数据进行降维,并选用余弦相似度(cosine)核作为kernal-PCA的最佳核函数,最后分别将PCA和kernal-PCA降维处理后的数据进行k-近邻算法(KNN)训练。结果表明,kernal-PCA+KNN的模型准确率(95.17%)优于PCA+KNN模型的准确率(92.34%)。研究表明,kernal-PCA+KNN算法可以实现15类废旧纺织物识别准确率的提升,为废旧纺织物在线近红外自动分拣提供有力的技术支撑。

基于SRCC与Bayes_KNN的涡扇发动机剩余使用寿命预测

利用斯皮尔曼秩相关系数(SRCC)、贝叶斯(Bayesian)、k最近邻(KNN)算法提出了一种新的航空发动机剩余使用寿命预测方法。为解决关键特征提取不足问题,首先,利用SRCC方法对发动机的历史多元监测特征进行筛选,提取出衰退性能趋势明显的监测特征作为预测模型的输入;其次,构建了基于欧式距离的k最近邻回归预测模型,利用贝叶斯更新公式对KNN中的超参数模型进行训练,求解目标函数并返回训练模型最优超参数值与最小均方根误差;最后,推导航空发动机剩余使用寿命(RUL)概率密度函数解析式,得到发动机RUL预测结果。采用CMAPSS数据集验证所提方法的有效性,结果表明,与其他预测方法相比该方法具有更优的预测性能,有效提升了发动机RUL预测的精确度。

一种面向工业应用的机器人回位方法

针对工业机器人作业过程中非正常停机引起位姿处于未知状态而导致机器人无法从停机位置自动返回初始位置的问题,提出一种工业机器人的回位方法。设计机器人回位路径,结合k-近邻算法、构造回位空间以及空间分类阈值对机器人的位姿信息进行分类化处理;重构机器人特征数据进行决策树模型的训练;使用训练完成的模型决策回位路径后执行机器人回位程序,实现工业机器人自动返回初始位。回位试验实验结果表明:在随机位姿和携带多样工具的状态下机器人回位成功率为93.3%。

Rapid prediction of flow and concentration fields in solid-liquid suspensions of slurry electrolysis tanks

Slurry electrolysis(SE),as a hydrometallurgical process,has the characteristic of a multitank series connection,which leads to various stirring conditions and a complex solid suspension state.The computational fluid dynamics(CFD),which requires high computing resources,and a combination with machine learning was proposed to construct a rapid prediction model for the liquid flow and solid concentration fields in a SE tank.Through scientific selection of calculation samples via orthogonal experiments,a comprehensive dataset covering a wide range of conditions was established while effectively reducing the number of simulations and providing reasonable weights for each factor.Then,a prediction model of the SE tank was constructed using the K-nearest neighbor algorithm.The results show that with the increase in levels of orthogonal experiments,the prediction accuracy of the model improved remarkably.The model established with four factors and nine levels can accurately predict the flow and concentration fields,and the regression coefficients of average velocity and solid concentration were 0.926 and 0.937,respectively.Compared with traditional CFD,the response time of field information prediction in this model was reduced from 75 h to 20 s,which solves the problem of serious lag in CFD applied alone to actual production and meets real-time production control requirements.

一种基于卷积神经网络的室内定位方法

针对实际室内定位场景中的无线接入点信号不稳定引起定位精度低的问题,提出一种基于卷积神经网络的室内定位方法,该方法包括离线阶段和在线阶段,其中离线阶段主要完成对无线接入点信号采集,经过预处理后作为卷积神经网络模型的训练数据。在线阶段利用训练好的模型完成粗定位,估计位置所在的区域,最后利用加权k近邻算法计算精确的位置坐标。通过与SVR、KNN算法对比,结果表明,在二维平面回归定位问题中优于其他算法。

城市轨道交通超短时客流预测模型研究及应用

超短时客流预测是城市轨道交通调度指挥中的关键基础性问题,现有的方法及模型各有优缺点,尚不能很好地满足现场实际工作需要。首先,基于上海城市轨道交通海量客流数据,对客流特征及其影响因素进行提取与分析,在此基础上引入“K最近邻算法”研究建立超短时客流预测模型。以上海城市轨道交通网络为实际背景的初步应用及结果分析表明,研究成果能对运营当天早晚高峰时段(7:00—10:00和17:00—20:00)客流做出超短时预测,具有较好的准确性、时效性和实用性,为调度指挥提供有力的客流数据支撑,助力构建城市轨道交通网络智慧客运组织调度系统。

Optimizing Clear Air Turbulence Forecasts Using the K-Nearest Neighbor Algorithm

The complexity and unpredictability of clear air turbulence(CAT)pose significant challenges to aviation safety.Accurate prediction of turbulence events is crucial for reducing flight accidents and economic losses.However,traditional turbulence prediction methods,such as ensemble forecasting techniques,have certain limitations:they only consider turbulence data from the most recent period,making it difficult to capture the nonlinear relationships present in turbulence.This study proposes a turbulence forecasting model based on the K-nearest neighbor(KNN)algorithm,which uses a combination of eight CAT diagnostic features as the feature vector and introduces CAT diagnostic feature weights to improve prediction accuracy.The model calculates the results of seven years of CAT diagnostics from 125 to 500 hPa obtained from the ECMWF fifth-generation reanalysis dataset(ERA5)as feature vector inputs and combines them with the labels of Pilot Reports(PIREP)annotated data,where each sample contributes to the prediction result.By measuring the distance between the current CAT diagnostic variable and other variables,the model determines the climatically most similar neighbors and identifies the turbulence intensity category caused by the current variable.To evaluate the model’s performance in diagnosing high-altitude turbulence over Colorado,PIREP cases were randomly selected for analysis.The results show that the weighted KNN(W-KNN)model exhibits higher skill in turbulence prediction,and outperforms traditional prediction methods and other machine learning models(e.g.,Random Forest)in capturing moderate or greater(MOG)level turbulence.The performance of the model was confirmed by evaluating the receiver operating characteristic(ROC)curve,maximum True Skill Statistic(maxTSS=0.552),and reliability plot.A robust score(area under the curve:AUC=0.86)was obtained,and the model demonstrated sensitivity to seasonal and annual climate fluctuations.

一种基于近邻搜索的快速k-近邻分类算法

针对传统快速k 近邻分类算法的缺陷 ,提出了一种基于近邻搜索的快速k 近邻分类算法———超球搜索法。该方法通过对特征空间的预组织 ,使分类在以待分样本为中心的超球内进行 ,有效地缩小了搜索范围。实验结果表明 ,在相同识别率和k值的情况下 ,超球搜索法的识别速度优于基本k 近邻法和传统快速k 近邻算法———及时终止法 。

一种基于信息增益的K-NN改进算法

针对传统K-NN算法易受单个属性干扰和时间效率较低的问题,提出了利用信息增益和可拓关联度对其进行改进。通过计算属性的信息增益来确定属性的权重系数,根据权重系数将属性划分为关键属性、次要属性和无关属性,在计算欧氏距离时引入权重系数,使各个属性的作用受其重要性的约束,有效地提高了K-NN算法的抗干扰能力和精确性。将属性空间划分为若干个子空间,利用可拓关联度将待测样本映射到某个子空间中,由这个子空间组成搜索空间,减少计算量,提高时间效率;测试结果表明,改进后的算法可行有效。

一种基于信息增益的K-NN改进算法

K-最近邻(K-nearestneighbor,简称KNN)算法是一种在人工智能领域如专家系统、数据挖掘、模式识别等方面广泛应用的算法。该算法简单有效,易于实现,但是其K值难以确定,而且分类结果易受单个属性干扰。文中提出了一种简单易行的K值确定方法,并利用Quinlan信息增益理论,提出了基于信息增益的K-最近邻改进算法。通过实验证明,改进后的K-NN算法具有较强的抗干扰能力和较好的精确性。

一种混合局部搜索算法的遗传算法求解旅行商问题

针对遗传算法容易产生早熟现象以及局部寻优能力较差的缺点,提出一种求解旅行商问题的高效混合遗传算法。该算法首先用加权最近邻法产生初始种群,对种群中相同的个体,用K-近邻法产生新的个体代替相同的个体,然后淘汰适应性较差的个体,用交叉操作产生新的个体,最后,对部分个体进行3-opt优化变异,对种群中优秀个体用改进的Lin-Kernighan算法进行优化。对TSPLIB中部分实例的仿真结果表明,所提出的混合局部搜索算法的改进遗传算法在求解TSP问题时可以高效地获得高质量的解。

基于多种机器学习方法填补大豆基因组缺失的比较研究

为探索大豆基因组测序不同程度缺失数据的有效填补措施,提升数据分析综合能力,本研究以大豆株高与叶面积两组性状的基因组基因型数据为研究对象,进行5%、10%和20%不同缺失比例的人为数据缺失处理,分别运用K近邻算法、SoftImpute算法和随机森林算法3种机器学习方法对缺失数据进行填补,分析填补数据的准确性和性能。对原始数据和填补后的数据进行全基因组关联分析,分别对比填补后的数据和原始数据的分析效果。从准确率来看,随机森林算法填补的准确率最高;从运行时间上来看,SoftImpute算法的运行速度最快;运行内存方面,SoftImpute算法的运行内存最小,而当数据量达到10 000×1 000时,K近邻填补算法的运行内存最小。在不考虑运行时间和运行内存的因素,且对填补的准确率要求较高的情况下,随机森林算法的填补效果要优于K近邻填补算法和SoftImpute算法,若对运行时间要求较高且数据量较大时,则应选择SoftImpute算法,同种情况下若对运行内存要求较高时,可优先考虑K近邻填补算法。结果说明不同机器学习方法在不同缺失程度的填补需求下的适用性,可应用于大豆基因组数据缺失处理。

SVM-KNN分类器——一种提高SVM分类精度的新方法

本文提出了一种将支持向量机分类和最近邻分类相结合的方法 ,形成了一种新的分类器 .首先对支持向量机进行分析可以看出它作为分类器实际相当于每类只选一个代表点的最近邻分类器 ,同时在对支持向量机分类时出错样本点的分布进行研究的基础上 ,在分类阶段计算待识别样本和最优分类超平面的距离 ,如果距离差大于给定阈值直接应用支持向量机分类 ,否则代入以每类的所有的支持向量作为代表点的K近邻分类 .数值实验证明了使用支持向量机结合最近邻分类的分类器分类比单独使用支持向量机分类具有更高的分类准确率 。