Computer Sciences Commons^™

Conference: Report Conectar 2019, Marcela Alfaro Córdoba, Frans Van Dunné, Agustín Gómez Meléndez, Jacob Van Etten

The R Journal

ConectaR 2019: Encuentro de Usuarios R en Latinoamérica, took place during January 24-26, 2019 at the University of Costa Rica, in San José, Costa Rica. It was the first event in Central America endorsed by The R Foundation, and it was held completely in Spanish. The majority of the attendants were from Costa Rica (85%), but we had participants from 12 countries: Costa Rica, Guatemala, Peru, Colombia, Mexico, Argentina, Uruguay, Chile, Spain, the Netherlands, France and the USA. The three-day event consisted of talks, workshops, and poster sessions.

Lpirfs: An R Package To Estimate Impulse Response Functions By Local Projections, Philipp Adämmer

The R Journal

Impulse response analysis is a cornerstone in applied (macro-)econometrics. Estimating impulse response functions using local projections (LPs) has become an appealing alternative to the traditional structural vector autoregressive (SVAR) approach. Despite its growing popularity and applications, however, no R package yet exists that makes this method available. In this paper, I introduce lpirfs, a fast and flexible R package that provides a broad framework to compute and visualize impulse response functions using LPs for a variety of data sets.

Roahd Package: Robust Analysis Of High Dimensional Data, Francesca Ieva, Anna Maria Paganoni, Juan Romo, Nicholas Tarabelloni

The R Journal

The focus of this paper is on the open-source R package roahd (RObust Analysis of High dimensional Data), see Tarabelloni et al. (2017). roahd has been developed to gather recently proposed statistical methods that deal with the robust inferential analysis of univariate and multivariate functional data. In particular, efficient methods for outlier detection and related graphical tools, methods to represent and simulate functional data, as well as inferential tools for testing differences and dependency among families of curves will be discussed, and the associated functions of the package will be described in details.

Cvcrand: A Package For Covariate-Constrained Randomization And The Clustered Permutation Test For Cluster Randomized Trials, Hengshi Yu, Fan Li, John A. Gallis, Elizabeth L. Turner

The R Journal

The cluster randomized trial (CRT) is a randomized controlled trial in which randomization is conducted at the cluster level (e.g., school or hospital) and outcomes are measured for each individual within a cluster. Often, the number of clusters available to randomize is small (≤ 20), which increases the chance of baseline covariate imbalance between comparison arms. Such imbalance is particularly problematic when the covariates are predictive of the outcome because it can threaten the internal validity of the CRT. Pair-matching and stratification are two restricted randomization approaches that are frequently used to ensure balance at the design stage. An alternative, …

Ppci: An R Package For Cluster Identification Using Projection Pursuit, David P. Hofmeyr, Nicos G. Pavlidis

The R Journal

This paper presents the R package PPCI which implements three recently proposed projection pursuit methods for clustering. The methods are unified by the approach of defining an optimal hyperplane to separate clusters, and deriving a projection index whose optimiser is the vector normal to this separating hyperplane. Divisive hierarchical clustering algorithms that can detect clusters defined in different subspaces are readily obtained by recursively bi-partitioning the data through such hyperplanes. Projecting onto the vector normal to the optimal hyperplane enables visualisations of the data that can be used to validate the partition at each level of the cluster hierarchy. Clustering …

Orthodr: Semiparametric Dimension Reduction Via Orthogonality Constrained, Ruoqing Zhu, Jiyang Zhang, Ruilin Zhao, Peng Xu, Wenzhuo Zhou, Xin Zhang

The R Journal

orthoDr is a package in R that solves dimension reduction problems using orthogonality constrained optimization approach. The package serves as a unified framework for many regression and survival analysis dimension reduction models that utilize semiparametric estimating equations. The main computational machinery of orthoDr is a first-order algorithm developed by Wen and Yin (2012) for optimization within the Stiefel manifold. We implement the algorithm through Rcpp and OpenMP for fast computation. In addition, we developed a general-purpose solver for such constrained problems with user-specified objective functions, which works as a drop-in version of optim(). The package also serves as a platform …

Using Web Services To Work With Geodata In R, Jan-Philipp Kolb

The R Journal

Through collaborative mapping, a massive amount of data is accessible. Many individuals contribute information each day. The growing amount of geodata is gathered by volunteers or obtained via crowd-sourcing. One outstanding example of this is the OpenStreetMap (OSM) Project which provides access to big data in geography. Another online mapping service that enables the integration of geodata into the analysis is Google Maps. The expanding content and the availability of geographic information radically changes the perspective on geodata (Chilton 2009). Recently many application programming interfaces (APIs) have been built on OSM and Google Maps. That leads to a point where …

Spgarch: An R-Package For Spatial And Spatiotemporal Arch And Garch Models, Philipp Otto

The R Journal

In this paper, a general overview on spatial and spatiotemporal ARCH models is provided. In particular, we distinguish between three different spatial ARCH-type models. In addition to the original definition of Otto et al. (2016), we introduce an logarithmic spatial ARCH model in this paper. For this new model, maximum-likelihood estimators for the parameters are proposed. In addition, we consider a new complex-valued definition of the spatial ARCH process. Moreover, spatial GARCH models are briefly discussed. From a practical point of view, the use of the R-package spGARCH is demonstrated. To be precise, we show how the proposed spatial ARCH …

Hcmodelsets: An R Package For Specifying Sets Of Well-Fitting Models In High Dimensions, Henrique Hoeltgebaum, Heather Battey

The R Journal

In the context of regression with a large number of explanatory variables, Cox and Battey (2017) emphasize that if there are alternative reasonable explanations of the data that are statistically indistinguishable, one should aim to specify as many of these explanations as is feasible. The standard practice, by contrast, is to report a single effective model for prediction. This paper illustrates the R implementation of the new ideas in the package HCmodelSets, using simple reproducible examples and real data. Results of some simulation experiments are also reported.

The R Package Trafo For Transforming Linear Regression Models, Lily Medina, Ann-Kristin Kreutzmann, Natalia Rojas-Perilla, Piedad Castro

The R Journal

Researchers and data-analysts often use the linear regression model for descriptive, predictive, and inferential purposes. This model relies on a set of assumptions that, when not satisfied, yields biased results and noisy estimates. A common problem that can be solved in many ways – use of less restrictive methods (e.g. generalized linear regression models or non-parametric methods ), variance corrections or transformations of the response variable just to name a few. We focus on the latter option as it allows to keep using the simple and well-known linear regression model. The list of transformations proposed in the literature is long …

Comparing Namedcapture With Other R Packages For Regular Expressions, Toby Dylan Hocking

The R Journal

Regular expressions are powerful tools for manipulating non-tabular textual data. For many tasks (visualization, machine learning, etc), tables of numbers must be extracted from such data before processing by other R functions. We present the R package namedCapture, which facilitates such tasks by providing a new user-friendly syntax for defining regular expressions in R code. We begin by describing the history of regular expressions and their usage in R. We then describe the new features of the namedCapture package, and provide detailed comparisons with related R packages (rex, stringr, stringi, tidyr, rematch2, re2r).

News From The Bioconductor Project, Bioconductor Core Team

The R Journal

The Bioconductor project provides tools for the analysis and comprehension of high-throughput genomic data. Bioconductor 3.10 was released on 30 October, 2019. It is compatible with R 3.6.1 and consists of 1823 software packages, 384 experiment data packages, 953 up-to-date annotation packages, and 27 workflows. The release announcement includes descriptions of 94 new software packages, and updated NEWS files for many additional packages. Start using Bioconductor by installing the most recent version of R and evaluating the commands

Fitting Tails By The Empirical Residual Coefficient Of Variation: The Ercv Package, Joan Del Castillo, Isabel Serra, Maria Padilla, David Moriña

The R Journal

This article is a self-contained introduction to the R package ercv and to the methodology on which it is based through the analysis of nine examples. The methodology is simple and trustworthy for the analysis of extreme values and relates the two main existing methodologies. The package contains R functions for visualizing, fitting and validating the distribution of tails. It also provides multiple threshold tests for a generalized Pareto distribution, together with an automatic threshold selection algorithm.

Changes On Cran, Kurt Hornik, Uwe Ligges, Achim Zeileis

The R Journal

In the past 4 months, 632 new packages were added to the CRAN package repository. 27 packages were unarchived and 182 were archived. The following shows the growth of the number of active packages in the CRAN package repository:

Rollmatch: An R Package For Rolling Entry Matching, Kasey Jones, Rob Chew, Allison Witman, Yiyan Liu

The R Journal

The gold standard of experimental research is the randomized control trial. However, interventions are often implemented without a randomized control group for practical or ethical reasons. Propensity score matching (PSM) is a popular method for minimizing the effects of a randomized experiment from observational data by matching members of a treatment group to similar candidates that did not receive the intervention. Traditional PSM is not designed for studies that enroll participants on a rolling basis and does not provide a solution for interventions in which the baseline and intervention period are undefined in the comparison group. Rolling Entry Matching (REM) …

Editorial, Michael J. Kane

The R Journal

On behalf of the editorial board, I am pleased to present Volume 11, Issue 2 of the R Journal and my first issue as the Editor in Chief. This year, both Colin Gillespie and Catherine Healey join the Editorial Board, and Norm Matloff will rotate out. The R Journal continues to see increases in impact and popularity and this year we plan on making advances to better serve the community and streamline the publishing process to meet the increase in submissions we have seen over the last few years.

Dr4pl: A Stable Convergence Algorithm For The 4 Parameter Logistic Model, Hyowon An, Justin T. Landis, Aubrey G. Bailey, James S. Marron, Dirk P. Dittmer

The R Journal

The 4 Parameter Logistic (4PL) model has been recognized as a major tool to analyze the relationship between doses and responses in pharmacological experiments. A main strength of this model is that each parameter contributes an intuitive meaning enhancing interpretability of a fitted model. However, implementing the 4PL model using conventional statistical software often encounters numerical errors. This paper highlights the issue of convergence failure and presents several causes with solutions. These causes include outliers and a non-logistic data shape, so useful remedies such as robust estimation, outlier diagnostics and constrained optimization are proposed. These features are implemented in a …

Associative Classification In R: Arc, Arulescba, And Rcba, Michael Hahsler, Ian Johnson, Tomáš Kliegr, Jaroslav Kuchař

The R Journal

Several methods for creating classifiers based on rules discovered via association rule mining have been proposed in the literature. These classifiers are called associative classifiers and the best-known algorithm is Classification Based on Associations (CBA). Interestingly, only very few implementations are available and, until recently, no implementation was available for R. Now, three packages provide CBA. This paper introduces associative classification, the CBA algorithm, and how it can be used in R. A comparison of the three packages is provided to give the potential user an idea about the advantages of each of the implementations. We also show how the …

Convergenceclubs: A Package For Performing The Phillips And Sul's Club Convergence Clustering Procedure, Roberto Sichera, Pietro Pizzuto

The R Journal

This paper introduces package ConvergenceClubs, which implements functions to perform the Phillips and Sul (2007, 2009) club convergence clustering procedure in a simple and reproducible manner. The approach proposed by Phillips and Sul to analyse the convergence patterns of groups of economies is formulated as a nonlinear time varying factor model that allows for different time paths as well as individual heterogeneity. Unlike other approaches in which economies are grouped a priori, it also allows the endogenous determination of convergence clubs. The algorithm, usage, and implementation details are discussed.

R News, R Core Team

The R Journal

CHANGES IN R 3.6.2

CHANGES IN R 3.6.0

CHANGES IN R 3.5.3

CHANGES IN R 3.5.2

CHANGES IN R 3.5.1

CHANGES IN R 3.5.0

CHANGES IN R 3.4.4

CHANGES IN R 3.4.3

CHANGES IN R 3.4.2

CHANGES IN R 3.4.1

CHANGES IN R 3.4.0

CHANGES IN R 3.3.3

CHANGES IN R 3.3.2

CHANGES IN R 3.3.1

CHANGES IN R 3.3.0

CHANGES IN R 3.2.5

CHANGES IN R 3.2.4

CHANGES IN R 3.2.3

CHANGES IN R 3.2.2

CHANGES IN R 3.2.1

CHANGES IN R 3.2.0

CHANGES IN R 3.1.3

CHANGES IN R 3.1.2

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CHANGES IN R 3.1.0 …

Time Series Forecasting With Knn In R: The Tsfknn Package, Francisco Martínez, María P. Frías, Francisco Charte, Antonio J. Rivera

The R Journal

In this paper the tsfknn package for time series forecasting using k-nearest neighbor regression is described. This package allows users to specify a KNN model and to generate its forecasts. The user can choose among different multi-step ahead strategies and among different functions to aggregate the targets of the nearest neighbors. It is also possible to assess the forecast accuracy of the KNN model.

Bondvaluation: An R Package For Fixed Coupon Bond Analysis, Wadim Djatschenko

The R Journal

t The purpose of this paper is to introduce the R package BondValuation for the analysis of large datasets of fixed coupon bonds. The conceptual heterogeneity of fixed coupon bonds traded in the global markets imposes a high degree of complexity on their comparative analysis. Contrary to baseline fixed income theory, in practice, most bonds feature coupon period irregularities. In addition, there are a multitude of day count methods that determine the interest accrual, the cash flows and the discount factors used in bond valuation. Several R packages, e.g., fBonds, RQuantLib, and YieldCurve, provide tools for fixed income analysis. Nevertheless, …

Arkitektura E Mikroshërbimeve Duke Perdorur .Net Core Dhe Reactjs, Gurakuq Krasniqi

Theses and Dissertations

Në këtë punim diplome do të trajtohet implementimi i arkitekturës së mikroshërbimeve duke përdorur teknologjitë më bashkëkohore si .NET Core dhe React duke u bazuar në sistemin për menaxhimin e temës së diplomës. Mënyra e dizajnimit të arkitekturës softuerike ka evoluar që nga fillimi i përdorimit e deri në ditët e sotme dhe si rezultat i evoluconit kemi dizajne të ndryshme, ku secila nga to përdoret varësisht nga specifikat e sistemit dhe kërkesat që ato i përshtaten në mënyrën më efektive. Qëllimi kryesor i këtij punimi të diplomës është shtjellimi i realizimit dhe implementimit të sistemit për menaxhimin e temave …

Analiza E “Student Response System” Dhe Impakti I Tyre Në Ngritjen E Ndërveprimit Brenda Klasës, Kimete Haxhiu

Theses and Dissertations

Involvimi i teknologjisë po bëhet një komponentë thelbësore e klasës moderne dhe studentët kanë nevojë për mjete të tilla për të rritur interaktivitetin dhe të nxënit e tyre. Student Response Systems apo SRS, kujdesen pikërisht për këtë nevojë dhe përfaqësojnë disa nga teknologjitë më të mira dhe më të reja të arsimit që gjenden sot. Student Response System lejon mësimdhënësit të parashtrojnë pyetje ose të trajtojnë një problem në klasë, ku përmes tyre studentët japin përgjigjet e tyre në një pajisje dhe menjëherë grumbullohen përgjigjet e tyre për mësimdhënësin. Kjo ofron një mbështetje për procesin mësimor, duke marrë parasyshë që …

Zhvillimi I Sistemit Për Monitorim Të Ardhjes Dhe Largimit Nga Puna - Bazuar Në Java Sockets, Redon Bejtullahu

Theses and Dissertations

Sistemet për monitorimin e ardhjes dhe largimit nga puna bëjnë monitorimin e saktë dhe preciz të kohës së qëndrimit në orar të punës. Sistemet mund të gjenerojnë statistika komplekse rreth monitorimit të aktivitetit të punëtorit. Fokusi i zhvillimit të një sistemi të tillë është kontrolli i vijueshmërisë së punëtorëve në punë duke përfshirë largimet e hershme nga puna dhe tej zgjatjet e pauzave. Sistemi i monitorimit është i ndarë në dy pjesë atë administrative dhe pjesa raportuese, pjesa administrative kontrollon të gjithë sistemin dhe është përgjegjëse për monitorimin e tij, ndërsa pjesa raportuese përbëhet nga pajisja e cila bartet nga …

Privatësia Ne Sistemet Rekomanduese, Krist Domgjoni

Theses and Dissertations

Sistemet rekomanduese janë shumë të përdorshme në ditet e sotme. Ato përdoren në internet për të ndihmuar një shfrytëzues të gjej një produkt të deshiruar në kohë sa më të shpejtë. SR pothuajse gjenden në çdo faqe të internetit, sidomos në kompanitë e mëdha siç janë: Facebook, eBay, Amazon, NetFlix etj. Në raste konkrete këto sisteme ndihmojnë që përdoruesi të gjejë një libër, film, artikull, produkt me preferenca të tij, poashtu në rrjetet sociale përdoren për të takuar shokë që kanë interesa të njejta në fusha të ndryshme. Këto kompani I përdorin sistemet rekomanduese sepse sjellin përfitime marramendëse në kohë …

Dizajnimi I Web Faqës Së Shpedicionit “Vjosa”, Fitore Bajrami

Theses and Dissertations

Në këtë temë diplome do të trajtohet krijimi dhe dizajnimi i një Web faqeje të Agjensionit Doganor (shpedicioni) “VJOSA”.

Krijimi i Web faqes është bërë me gjuhët e shënjimit (markup language) siç janë HTML dhe JavaScript po ashtu edhe me programet e Adobe si Photoshop dhe Dreamweaver dhe duke i kushtuar shumë rëndësi dizajnit të Web-it.

Në kapitullin e fundit do të prezentojmë Web faqen e Shpedicionit Vjosa ku demonstrohen disa parime të cilat duhet t’i ketë nje web faqe për të tërhequr vizitorët siç janë: lehtësia për të naviguar, përmbajtja e mirë, informacione relevante dhe të sakta, funksione te …

Zhvillimi I Ueb Aplikacionit Për Menaxhimin E Qendrave Të Karrierës: Ubt Campus, Elhame Krasniqi

Theses and Dissertations

Ueb aplikacionet janë bërë pjesë e rëndësishme e bizneseve dhe institucioneve në përgjithësi pasi janë duke mundësuar shkëmbim dhe menaxhim të informacionit nga të gjitha vendet ku do që ndodhemi, rëndësia e ueb aplikacioneve responsive është një mundësi e mirë për tu përshtatur pajisjeve të ndryshme. Qëllimi i këtij studimi është të ofrojmë njohuri shtesë rreth praktikimit të këtyre aplikacioneve nga institucionet e arsimit të lartë, më saktësisht se si këto ueb aplikacioneve do të mund t’iu ofrojnë studenteve një ambient më të mirë për komunikim me njeri tjetrin e deri tek menaxhimi më i mirë i qendrave të karrierës …

Efektet E Digjitalizimit Të Shërbimeve Publike Te Bizneset - Rast Studimi Komuna E Ferizajit, Ardit Mehmeti

Theses and Dissertations

Zhvillimi dhe përdorimi i TIK-ut (Teknologjia e Informatave dhe Komunikimit) rezultoi me krijimin e Shoqërisë Informative, në epiqendrën e së cilës është roli i informatave në shoqërinë e sotme. Ky zhvillim aq i hovshëm ka ndikuar në masë të madhe edhe në marrëdhëniet në mes të institucioneve dhe komunitetit të biznesit. Biznesi elektronik është forma më bashkohore e organizimit e cila në masë të madhe varet nga përdorimi i teknologjisë informatike, përkatësisht përdorimi i këtyre aplikimeve, sistemeve apo platformave. TIK ka lehtësuar të bërit biznes duke zgjeruar me lehtë tregun, duke ulur kostot e shpenzimeve, kursimin e kohës, duke ngritur …

C# Implementimi I Capsule Network Në Detektimin E Objekteve Në Imazhe, Bashkim Salihu

Theses and Dissertations

Rrjeti me kapsula apo CapsNet është një qasje e re dhe interesante për zgjidhjen e problemeve në Computer Vision. Me publikimet e fundit është vërtetuar se kjo qasje e re është e saktë në detektimin e objekteve edhe nëse ato objekte janë të shtrembëruara apo pamja është prej një këndi tjetër. Implementimi i CapsNet është realizuar në shumicën e gjuhëve programuese si Python, R, Java etj.

Në këtë temë është bërë implementimi në C# duke përdorur Microsoft Cognitive Toolkit (CNTK), si vegël per krijimin e modelit dhe trajnimin e tij. Rezultatet e fituara pas implementimit na tregojnë se implementimi në …