Numerical Analysis and Scientific Computing Commons^™

Approximating The Sum Of Independent Non-Identical Binomial Random Variables, Boxiang Liu, Thomas Quertermous

The R Journal

The distribution of the sum of independent non-identical binomial random variables is frequently encountered in areas such as genomics, healthcare, and operations research. Analytical solutions for the density and distribution are usually cumbersome to find and difficult to compute. Several methods have been developed to approximate the distribution, among which is the saddlepoint approximation. However, implementation of the saddlepoint approximation is non-trivial. In this paper, we implement the saddlepoint approximation in the sinib package and provide two examples to illustrate its usage. One example uses simulated data while the other uses real-world healthcare data. The sinib package addresses the gap …

Nonparametric Independence Tests And K-Sample Tests For Large Sample Sizes Using Package Hhg, Barak Brill, Yair Heller, Ruth Heller

The R Journal

Nonparametric tests of independence and k-sample tests are ubiquitous in modern applications, but they are typically computationally expensive. We present a family of nonparametric tests that are computationally efficient and powerful for detecting any type of dependence between a pair of univariate random variables. The computational complexity of the suggested tests is sub-quadratic in sample size, allowing calculation of test statistics for millions of observations. We survey both algorithms and the HHG package in which they are implemented, with usage examples showing the implementation of the proposed tests for both the independence case and the k-sample problem. The tests are …

The R Journal (July 2018) 10(1): Complete Issue, The R Foundation

The R Journal

Editorial, John Verzani

Contributed Research Articles

A System for an Accountable Data Analysis Process in R, Jonathan Gelfond, Martin Goros, Brian Hernandez and Alex Bokov

RealVAMS: An R Package for Fitting a Multivariate Value-added Model (VAM), Jennifer Broatch, Jennifer Green, and Andrew Karl

InfoTrad: An R Package for Estimating the Probability of Informed Trading, Duygu Çelik and Murat Tiniç

RatingScaleReduction Package: Stepwise Rating Scale Item Reduction without Predictability Loss, Waldemar W. Koczkodaj, Feng Li, and Alicja Wolny-Dominiak

mmpf: Monte-Carlo Methods for Prediction Functions, Zachary M. Jones

Generalized Additive Model Multiple Imputation by Chained Equations with Package ImputeRobust, Daniel Salfran and …

Grpstring: An R Package For Analysis Of Groups Of Strings, Hui Tang, Elizabeth L. Day, Molly B. Atkinson, Norbert J. Pienta

The R Journal

The R package GrpString was developed as a comprehensive toolkit for quantitatively analyzing and comparing groups of strings. It offers functions for researchers and data analysts to prepare strings from event sequences, extract common patterns from strings, and compare patterns be tween string vectors. The package also finds transition matrices and complexity of strings, determines clusters in a string vector, and examines the statistical difference between two groups of strings.

Lba: An R Package For Latent Budget Analysis, Enio G. Jelihovschi, Ivan Bezerra Allaman

The R Journal

The latent budget model is a mixture model for compositional data sets in which the entries, a contingency table, may be either realizations from a product multinomial distribution or distribution free. Based on this model, the latent budget analysis considers the interactions of two variables; the explanatory (row) and the response (column) variables. The package lba uses expectation-maximization and active constraints method (ACM) to carry out, respectively, the maximum likelihood and the least squares estimation of the model parameters. It contains three main functions, lba which performs the analysis, goodnessfit for model selection and goodness of fit and the plotting …

Tackling Uncertainties Of Species Distribution Model Projections With Package Mopa, M. Iturbide, J. Bedia, J.M. Gutiérrez

The R Journal

Species Distribution Models (SDMs) constitute an important tool to assist decision-making in environmental conservation and planning in the context of climate change. Nevertheless, SDM projections are affected by a wide range of uncertainty factors (related to training data, climate projections and SDM techniques), which limit their potential value and credibility. The new package mopa provides tools for designing comprehensive multi-factor SDM ensemble experiments, combining multiple sources of uncertainty (e.g. baseline climate, pseudo-absence realizations, SDM techniques, future projections) and allowing to assess their contribution to the overall spread of the ensemble projection. In addition, mopa is seamlessly integrated with the climate4R …

Panjen: An R Package For Ranking Transformations In A Linear Regression, Cathrine Ulla Jensen, Toke Emil Panduro

The R Journal

PanJen is an R-package for ranking transformations in linear regressions. It provides users with the ability to explore the relationship between a dependent variable and its independent variables. The package offers an easy and data-driven way to choose a functional form in multiple linear regression models by comparing a range of parametric transformations. The parametric functional forms are benchmarked against each other and a non-parametric transformation. The package allows users to generate plots that show the relation between a covariate and the dependent variable. Furthermore, PanJen will enable users to specify specific functional transformations, driven by a priori and theory-based …

Mmpf: Monte-Carlo Methods For Prediction Functions, Zachary M. Jones

The R Journal

Machine learning methods can often learn high-dimensional functions which generalize well but are not human interpretable. The mmpf package marginalizes prediction functions using Monte-Carlo methods, allowing users to investigate the behavior of these learned functions, as on a lower dimensional subset of input features: partial dependence and variations thereof. This makes machine learning methods more useful in situations where accurate prediction is not the only goal, such as in the social sciences where linear models are commonly used because of their interpretability.

Many methods for estimating prediction functions produce estimated functions which are not directly human-interpretable because of their complexity: …

Infotrad: An R Package For Estimating The Probability Of Informed Trading, Duygu Çelik, Murat Tiniç

The R Journal

The purpose of this paper is to introduce the R package InfoTrad for estimating the probability of informed trading (PIN) initially proposed by Easley et al. (1996). PIN is a popular information asymmetry measure that proxies the proportion of informed traders in the market. This study provides a short survey on alternative estimation techniques for the PIN. There are many problems documented in the existing literature in estimating PIN. InfoTrad package aims to address two problems. First, the sequential trading structure proposed by Easley et al. (1996) and later extended by Easley et al. (2002) is prone to sample selection …

Online Active Learning With Expert Advice, Shuji Hao, Peiying Hu, Peilin Zhao, Steven C. H. Hoi, Chunyan Miao

Research Collection School Of Computing and Information Systems

In literature, learning with expert advice methods usually assume that a learner always obtain the true label of every incoming training instance at the end of each trial. However, in many real-world applications, acquiring the true labels of all instances can be both costly and time consuming, especially for large-scale problems. For example, in the social media, data stream usually comes in a high speed and volume, and it is nearly impossible and highly costly to label all of the instances. In this article, we address this problem with active learning with expert advice, where the ground truth of an …

Modeling Recombination In Solar Cells, Paul Chery

Macalester Journal of Physics and Astronomy

Solar cells are a competitive alternative to nonrenewable energy sources such as fossil fuels. However, the efficiency of these devices is limited by photogenerated carrier recombination. We use a finite difference numerical model to study recombination phenomena in the absorber layer of solar cells including alternate recombination models and the effects of spatial distribution of recombination centers. We compare the effect of using the constant lifetime approximation for recombination to the full Shockley-Read-Hall expression in Silicon solar cells and find that the constant lifetime approximation holds for high defect densities but not for high photon flux densities. Finally, we simulate …

A Lightweight Modeling And Simulation Technical Framework For Complex Systems, Ji Hang, Junhua Zhou, Guoqiang Shi, Tingyu Lin, Junjie Xue

Journal of System Simulation

Abstract: Aiming at the modeling and simulation verification of complex systems, the paper established a lightweight simulation technical framework and a system building method. The simulation technical framework is built based on distributed network communication middleware and has graphic user interface, simulation management and run control modules, it packages effective and lightweight network middleware, object management, event management and time management and it is capable of interoperability and its members have abilities of reusable and combinable. The results show that the framework can supports flexible construction and effective simulation on complex systems.

Analysis And Simulation Of Temperature Control For Battery Pole Piece Electromagnetic Heating Roller, Jing Ran, Feng Hua, Yonggeng Wang, Haiping Song, Yanjun Xiao

Journal of System Simulation

Abstract: With the application of electromagnetic heating roller on battery pole piece rolling,the processing technology, quality and efficiency of the battery pole piece are improved. The special heating technology of electromagnetic heating roller which involves multi-physics coupling in the process of conversion makes it difficult to control the heating process and determine the control index. By studying the electromagnetic heating theory, the mathematical model of electromagnetic heating roller is established and the simulation and analysis of the electromagnetic heating roller using MATLAB software and the finite difference method are carried out. The distribution, change rule and influence factors of the …

Modeling & Simulation Technology In Manufacturing, Zhang Lin, Longfei Zhou

Journal of System Simulation

Abstract: With the continuous deepening of the application of information technology in the manufacturing field, the informatization of manufacturing systems is developing from unit digital manufacturing to integration networked manufacturing, and then to the comprehensive digital, networked and intelligent manufacturing. As a comprehensive information technology integrating computer, model theory, and scientific computing, modeling & simulation technology plays an irreplaceable role during the development of manufacturing informatization and is widely applied in all phases of the whole product lifecycle, such as design, manufacturing, testing, maintenance, purchase, sales and other phase. This paper reviews and summarizes the research and application of modeling …

Research On Maturity Evaluation Technology Of Complex Digital Industrial System, Geng Chao, Shiyou Qu, Tingyu Lin, Guoqiang Shi, Yingying Xiao, Wang Mei, Qiudan Ma, Ji Hang

Journal of System Simulation

Abstract: Under the background of a new round of the innovation of science and technology and the revolution of industry, the complex digital industrial system is constantly innovating and shaping. Firstly, the paper established maturity evaluation model of the complex digital industrial system based on system engineering. Then, the paper proposed multi - index maturity analysis method and multi - enterprise maturity synthesis method of the complex digital industrial system. Combined with the digital industrial system of aerospace complex product, an evaluation example is presented. The results show that the maturity evaluation method can be used to standardize and guide …

Clustering Method Based On Graph Data Model And Reliability Detection, Yanyun Cheng, Huisong Bian, Changsheng Bian

Journal of System Simulation

Abstract: For the data in feature space, traditional clustering algorithm can take clustering analysis directly. High-dimensional spatial data cannot achieve intuitive and effective graphical visualization of clustering results in 2D plane. Graph data can clearly reflect the similarity relationship between objects. According to the distance of the data objects, the feature space data are modeled as graph data by iteration. Cluster analysis based on modularity is carried out on the modeling graph data. The two-dimensional visualization of non-spherical-shape distribution data cluster and result is achieved. The concept of credibility of the clustering result is proposed, and a method is proposed, …

Equipment Rul Prediction Oriented Parallel Simulation Framework, Chenglong Ge, Yuanchang Zhu, Yanqiang Di, Zhiwei Hu, Zhihua Dong

Journal of System Simulation

Abstract: As the equipment states are complicated with uncertainty, predicting remaining useful life with self-updating ability has become a hard task. Simulation provides an effective way to solve the problem. The concept and technology framework of equipment remaining useful life prediction oriented parallel simulation are proposed based on parallel system theory and the concept, characteristics, capacity demands and functional compositions of parallel simulation are introduced. The main modeling technologies of equipment remaining useful life prediction oriented parallel simulation are discussed, which include awareness of equipment degradation state, construction of equipment degradation state space model and evolution of equipment degradation state …

Matlab-Based Physical Real-Time Simulation Platform Of Pmsm In Intelligent Test System, Mengru Wang, Zhou Shan, Jinbo Wang, Panpan Xue

Journal of System Simulation

Abstract: As the physical objects cannot simulate multiple failure modes to cooperate with space controller test, a solution that establishing the real-time physics simulation platform which contains the controlled object and the control system is proposed in this paper. In this solution, we established permanent magnet synchronous motor vector control model using MATLAB /Simulink toolbox of System Generator, then implemented on FPGA; After hardware extension, a complete closed-loop test system is constructed with the DUT(controller) and the motor simulation model; the model has high pointing and tracking precision. Besides simulating motor's normal functions, the model's parameters can be changed …

Monkey Algorithm For Solving Logistics Center Location Selection Problem, Xiaoping Xu, Dongjie Zhang

Journal of System Simulation

Abstract: The location selection of logistics center is the most basic problem that affects the whole development of logistics center; an improved monkey algorithm is used to solve the problem. The basic idea is that the chaos variables are used to generate the initial feasible solution of the monkey algorithm, the decreasing factor is taken as the climbing step in the climbing process and a chaotic search method is introduced in the looking process to improve the performance of the algorithm. Through simulation experiment, the solution results of typical function and logistics center location problem are given to illustrate the …

Simulation Analysis Of Nearest Neighbor Searching For Anti-Ship Missile Target Selector Performance, Sun Jie, Tianyun Wang, Huanyao Dai, Cuiqiong Mo, Zhao Jing

Journal of System Simulation

Abstract: In view of that the current admission comparing searching mode is difficult to adapt to the offshore operation of anti-ship missile in multi target selection, the nearest neighbor selector applied to the target search scheme is put forward. By setting the typical searching situation, a target searching model is established; and on the basis of reasonable simplification, the nearest neighbor selector capture probability of display expression is deduced. Typical scenes in numerical simulation show that the scheme based on distance criterion for admission multiple targets for prioritization effectively improves the search performance of the target. A …