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2016

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Articles 121 - 150 of 2698

Full-Text Articles in Computer Sciences

Qtools: A Collection Of Models And Tools For Quantile Inference, Marco Geraci Dec 2016

Qtools: A Collection Of Models And Tools For Quantile Inference, Marco Geraci

The R Journal

Quantiles play a fundamental role in statistics. The quantile function defines the distribution of a random variable and, thus, provides a way to describe the data that is specular but equivalent to that given by the corresponding cumulative distribution function. There are many advantages in working with quantiles, starting from their properties. The renewed interest in their usage seen in the last years is due to the theoretical, methodological, and software contributions that have broadened their applicability. This paper presents the R package Qtools, a collection of utilities for unconditional and conditional quantiles.


R Foundation News, Torsten Hothorn Dec 2016

R Foundation News, Torsten Hothorn

The R Journal

New benefectors

Donations

New supporting institutions

New supporting members


Ggfortify: Unified Interface To Visualize Statistical Results Of Popular R Packages, Yuan Yuan, Masaaki Horikoshi, Wenxuan Li Dec 2016

Ggfortify: Unified Interface To Visualize Statistical Results Of Popular R Packages, Yuan Yuan, Masaaki Horikoshi, Wenxuan Li

The R Journal

The ggfortify package provides a unified interface that enables users to use one line of code to visualize statistical results of many R packages using ggplot2 idioms. With the help of ggfortify, statisticians, data scientists, and researchers can avoid the sometimes repetitive work of using the ggplot2 syntax to achieve what they need.


Ake: An R Package For Discrete And Continuous Associated Kernel Estimations, Wanbitching E. Wansouwé, Sobom M. Somé, Célestin C. Kokonendji Dec 2016

Ake: An R Package For Discrete And Continuous Associated Kernel Estimations, Wanbitching E. Wansouwé, Sobom M. Somé, Célestin C. Kokonendji

The R Journal

Kernel estimation is an important technique in exploratory data analysis. Its utility relies on its ease of interpretation, especially based on graphical means. The Ake package is introduced for univariate density or probability mass function estimation and also for continuous and discrete regression functions using associated kernel estimators. These associated kernels have been proposed due to their specific features of variables of interest. The package focuses on associated kernel methods appropriate for continuous (bounded, positive) or discrete (count, categorical) data often found in applied settings. Furthermore, optimal bandwidths are selected by cross-validation for any associated kernel and by Bayesian methods …


Eicompare: Comparing Ecological Inference Estimates Across Ei And Ei:Rc, Loren Collingwood, Kassra Oskooii, Sergio Garcia-Rios, Matt Barreto Dec 2016

Eicompare: Comparing Ecological Inference Estimates Across Ei And Ei:Rc, Loren Collingwood, Kassra Oskooii, Sergio Garcia-Rios, Matt Barreto

The R Journal

Social scientists and statisticians often use aggregate data to predict individual-level behavior because the latter are not always available. Various statistical techniques have been developed to make inferences from one level (e.g., precinct) to another level (e.g., individual voter) that minimize errors associated with ecological inference. While ecological inference has been shown to be highly problematic in a wide array of scientific fields, many political scientists and analysis employ the techniques when studying voting patterns. Indeed, federal voting rights lawsuits now require such an analysis, yet expert reports are not consistent in which type of ecological inference is used. This …


Calculating Biological Module Enrichment Or Depletion And Visualizing Data On Large-Scale Molecular Maps With Acsnminer And Rnavicell Packages, Paul Deveau, Emmanuel Barillot, Valentina Boeva, Andrei Zinovyev, Eric Bonnet Dec 2016

Calculating Biological Module Enrichment Or Depletion And Visualizing Data On Large-Scale Molecular Maps With Acsnminer And Rnavicell Packages, Paul Deveau, Emmanuel Barillot, Valentina Boeva, Andrei Zinovyev, Eric Bonnet

The R Journal

Biological pathways or modules represent sets of interactions or functional relationships occurring at the molecular level in living cells. A large body of knowledge on pathways is organized in public databases such as the KEGG, Reactome, or in more specialized repositories, the Atlas of Cancer Signaling Network (ACSN) being an example. All these open biological databases facilitate analyses, improving our understanding of cellular systems. We hereby describe ACSNMineR for calculation of enrichment or depletion of lists of genes of interest in biological pathways. ACSNMineR integrates ACSNmolecular pathways gene sets, but can use any gene set encoded as a GMT file, …


Escape From Boxland, Barret Schloerke, Hadley Wickham, Dianne Cook, Heike Hofmann Dec 2016

Escape From Boxland, Barret Schloerke, Hadley Wickham, Dianne Cook, Heike Hofmann

The R Journal

A library of common geometric shapes can be used to train our brains for understanding data structure in high-dimensional Euclidean space. This article describes the methods for producing cubes, spheres, simplexes, and tori in multiple dimensions. It also describes new ways to define and generate high-dimensional tori. The algorithms are described, critical code chunks are given, and a large collection of generated data are provided. These are available in the R package geozoo, and selected movies and images, are available on the GeoZoo web site (http://schloerke.github.io/geozoo/)


Changes On Cran, Kurt Hornik, Achim Zeileis Dec 2016

Changes On Cran, Kurt Hornik, Achim Zeileis

The R Journal

CRAN growth

New CRAN task views

New packages in CRAN task views


Easyroc: An Interactive Web-Tool For Roc Curve Analysis Using R Language Environment, Dincer Goksuluk, Selcuk Korkmaz, Gokmen Zararsiz, A Ergun Karaagaoglu Dec 2016

Easyroc: An Interactive Web-Tool For Roc Curve Analysis Using R Language Environment, Dincer Goksuluk, Selcuk Korkmaz, Gokmen Zararsiz, A Ergun Karaagaoglu

The R Journal

ROC curve analysis is a fundamental tool for evaluating the performance of a marker in a number of research areas, e.g., biomedicine, bioinformatics, engineering etc., and is frequently used for discriminating cases from controls. There are a number of analysis tools which are used to guide researchers through their analysis. Some of these tools are commercial and provide basic methods for ROC curve analysis while others offer advanced analysis techniques and a command-based user interface, such as the R environment. The R environment includes comprehensive tools for ROC curve analysis; however, using a command-based interface might be challenging and time …


Hdm: High-Dimensional Metrics, Victor Chernozhukov, Chris Hansen, Martin Spindler Dec 2016

Hdm: High-Dimensional Metrics, Victor Chernozhukov, Chris Hansen, Martin Spindler

The R Journal

In this article the package High-dimensional Metrics hdm is introduced. It is a collection of statistical methods for estimation and quantification of uncertainty in high-dimensional approximately sparse models. It focuses on providing confidence intervals and significance testing for (possibly many) low-dimensional subcomponents of the high-dimensional parameter vector. Efficient estimators and uniformly valid confidence intervals for regression coefficients on target variables (e.g., treatment or policy variable) in a high-dimensional approximately sparse regression model, for average treatment effect (ATE) and average treatment effect for the treated (ATET), as well for extensions of these param eters to the endogenous setting are provided. Theory …


Distance Measures For Time Series In R: The Tsdist Package, Usue Mori, Alexander Mendiburu, Jose A. Lozano Dec 2016

Distance Measures For Time Series In R: The Tsdist Package, Usue Mori, Alexander Mendiburu, Jose A. Lozano

The R Journal

The definition of a distance measure between time series is crucial for many time series data mining tasks, such as clustering and classification. For this reason, a vast portfolio of time series distance measures has been published in the past few years. In this paper, the TSdist package is presented, a complete tool which provides a unified framework to calculate the largest variety of time series dissimilarity measures available in R at the moment, to the best of our knowledge. The package implements some popular distance measures which were not previously available in R, and moreover, it also provides wrappers …


Condsurv: An R Package For The Estimation Of The Conditional Survival Function For Ordered Multivariate Failure Time Data, Luis Meira-Machado, Meira-Machado Sestelo Dec 2016

Condsurv: An R Package For The Estimation Of The Conditional Survival Function For Ordered Multivariate Failure Time Data, Luis Meira-Machado, Meira-Machado Sestelo

The R Journal

One major goal in clinical applications of time-to-event data is the estimation of survival with censored data. The usual nonparametric estimator of the survival function is the time-honored Kaplan-Meier product-limit estimator. Though this estimator has been implemented in several R packages, the development of the condSURV R package has been motivated by recent contributions that allow the estimation of the survival function for ordered multivariate failure time data. The condSURV package provides three different approaches all based on the Kaplan-Meier estimator. In one of these approaches these quantities are estimated conditionally on current or past covariate measures. Illustration of the …


Measurement Units In R, Edzer Pebesma, Thomas Mailund, James Hiebert Dec 2016

Measurement Units In R, Edzer Pebesma, Thomas Mailund, James Hiebert

The R Journal

We briefly review SI units, and discuss R packages that deal with measurement units, their compatibility and conversion. Built upon udunits2 and the UNIDATA udunits library, we introduce the package units that provides a class for maintaining unit metadata. When used in expression, it automatically converts units, and simplifies units of results when possible; in case of incompatible units, errors are raised. The class flexibly allows expansion beyond predefined units. Using units may eliminate a whole class of potential scientific programming mistakes. We discuss the potential and limitations of computing with explicit units.


Tigris: An R Package To Access And Work With Geographic Data From The Us Census Bureau, Kyle Walker Dec 2016

Tigris: An R Package To Access And Work With Geographic Data From The Us Census Bureau, Kyle Walker

The R Journal

TIGER/Line shapefiles from the United States Census Bureau are commonly used for the mapping and analysis of US demographic trends. The tigris package provides a uniform interface for R users to download and work with these shapefiles. Functions in tigris allow R users to request Census geographic datasets using familiar geographic identifiers and return those datasets as objects of class "Spatial*DataFrame". In turn, tigris ensures consistent and high-quality spatial data for R users’ cartographic and spatial analysis projects that involve US Census data. This article provides an overview of the functionality of the tigris package, and concludes with an applied …


Mixtox: An R Package For Mixture Toxicity Assessment, Xiang-Wei Zhu, Jian-Yi Chen Dec 2016

Mixtox: An R Package For Mixture Toxicity Assessment, Xiang-Wei Zhu, Jian-Yi Chen

The R Journal

Mixture toxicity assessment is indeed necessary for humans and ecosystems that are continually exposed to a variety of chemical mixtures. This paper describes an R package, called mixtox, which offers a general framework of curve fitting, mixture experimental design, and mixture toxicity prediction for practitioners in toxicology. The unique features of mixtox include: (1) constructing a uniform table for mixture experimental design; and (2) predicting toxicity of a mixture with multiple components based on reference models such as concentration addition, independent action, and generalized concentration addition. We describe the various functions of the package and provide examples to illustrate their …


Water: Tools And Functions To Estimate Actual Evapotranspiration Using Land Surface Energy Balance Models In R, Guillermo Federico Olmedo, Samuel Ortega-Farías, Daniel De La Fuente-Sáiz, David Fonseca- Luego, Fernando Fuentes-Peñailillo Dec 2016

Water: Tools And Functions To Estimate Actual Evapotranspiration Using Land Surface Energy Balance Models In R, Guillermo Federico Olmedo, Samuel Ortega-Farías, Daniel De La Fuente-Sáiz, David Fonseca- Luego, Fernando Fuentes-Peñailillo

The R Journal

The crop water requirement is a key factor in the agricultural process. It is usually estimated throughout actual evapotranspiration (ETa). This parameter is the key to develop irrigation strategies, to improve water use efficiency and to understand hydrological, climatic, and ecosystem processes. Currently, it is calculated with classical methods, which are difficult to extrapolate, or with land surface energy balance models (LSEB), such as METRIC and SEBAL, which are based on remote sensing data. This paper describes water, an open implementation of LSEB. The package provides several functions to estimate the parameters of the LSEB equation from satellite data …


A Hypothesis Testing Approach For Topology Error Detection In Power Grids, Wei Biao Wu, Maggie X. Cheng, Bei Gou Dec 2016

A Hypothesis Testing Approach For Topology Error Detection In Power Grids, Wei Biao Wu, Maggie X. Cheng, Bei Gou

Computer Science Faculty Research & Creative Works

When the grid topology is changed due to incidents and the state estimator is not updated with the topological change, it is considered a topology error. In this paper, we develop a new method for detecting topology errors in power grids. The proposed method considers the measurement data as a nonstationary Gaussian process, explores the dependence structure of the underlying process. It detects errors by testing the hypothesis of whether the mean vector of a nonstationary Gaussian process is zero and does not rely on the convergence of the standard weighted least-squares (WLS) state estimation algorithm. It is very effective …


Web Aplikacionet Dinamike Me Java Ee, Jetë Leci Dec 2016

Web Aplikacionet Dinamike Me Java Ee, Jetë Leci

Theses and Dissertations

Qëllimi i kësaj teze të shkallës bachelor është bërë për analizimi dhe studimin e platformës më të mirë për zhvillimin e web aplikacioneve dinamike, ky studim nuk paraqet bazat e programimit në Java apo zhvillimin e pjesës së bazës së shënimeve ky studim ofron një pasqyrë të teknologjive dhe framework-ëve për implementimin e aplikacioneve me platformën Java Enterprise Edition. Ky kapitull perfshinë një përmbledhje të shkurtë të studimit dhe përvojës sime së bashku, duke shfaqur një pasqyrë të zhvillimit të aplikacioneve dinamike në web me anë të shpjegimit të secilës pjesë përbërëse të platformës shumë të njohur për realizimin e …


Analizimi Dhe Zhvillimi I Modulit Të Orarit Në Wordpress, Gëzim Rexhepi Dec 2016

Analizimi Dhe Zhvillimi I Modulit Të Orarit Në Wordpress, Gëzim Rexhepi

Theses and Dissertations

Përdorimi i një orari do të ishte një lehtësim i madh në menaxhimin e ngjarjeve të cilat ndodhin në një festival, si rezultat i kërkesave dhe nevojave për një orar i cili do të ishte lehtë i menaxhueshëm nga festivalet e ndryshme vendosa të zhvilloj ketë orar. Ky orar është dizajnuar dhe implementuar për festivalin “Dokufest”. Mirëpo ky orar mund të përdoret edhe nga festivale të tjera. Ky orar do ju ndihmoj festivaleve të ndryshme që të kenë më të lehtë shtimin e ngjarjeve të ndryshme e pastaj ato ngjarje ti shfaqin në këtë orar i cili është mjaft i …


Siguria Në Php, Shpat Ajvazi Dec 2016

Siguria Në Php, Shpat Ajvazi

Theses and Dissertations

Që të rezultojë me sukses një softuer duhet të përmbush shumë kritere, disa nga këto kriteret janë: efikasiteti, siguria dhe fleksibiliteti. Pavarësisht rëndësisë së softuerit çdo softuer duhet te ketë sigurinë në nivel të lartë duke mos lejuar të dhënat të përfundojnë në duar të personave të pa autorizuar. Pothuajse çdo ditë krijohen mundësi të reja për të sulmuar softuer-ët që funksionojnë përmes internet kjo tregon se siguria duhet të analizohet dhe që zhvilluesit gjithmonë duhet të ndjekin teknologjinë e fundit. Në pjesën kryesore shqyrtohen problemet dhe sulmet që bëhen në PHP sa i përket aspektit të sigurisë. Siguria e …


Zbatimi I Mpls Vpn Dhe Siguria, Fëllënza Bunjaku Dec 2016

Zbatimi I Mpls Vpn Dhe Siguria, Fëllënza Bunjaku

Theses and Dissertations

Viteve të fundit, temat e nivelit bachelor po ballafaqohen me një nga trendet më të mëdha në botën e rrjetave kompjuterike duke zgjuar poashtu edhe interesimin tim për të studiuar dhe punuar këtë temë aktuale por duke marr në shqyrtim zbatimin e Multiprotocol Label Switching-Virtual Private Network dhe Siguria të cilës në vazhdim të këtij punimi do t’i referohemi si (MPLS VPN).

Objektivi kryesor i këtij punimi është të kuptuarit e teknologjisë MPLS VPN përmes përkufizimit të kësaj teknologjie, si dhe paraqitjes së një skenario ku shqyrtohen protokolle të ndryshme të komunikimit. Shumica e ofruesve të shërbimeve (angl. ISP) që …


Android Drone: Remote Quadcopter Control With A Phone, Aubrey John Russell Dec 2016

Android Drone: Remote Quadcopter Control With A Phone, Aubrey John Russell

Computer Engineering

The purpose of the “Android Drone” project was to create a quadcopter that can be controlled by user input sent over the phone’s Wi-Fi connection or 4G internet connection. Furthermore, the purpose was also to be able to receive live video feedback over the internet connection, thus making the drone an inexpensive option compared to other, equivalent drones that might cost thousands of dollars. Not only that, but the Android phone also has a host of other useful features that could be utilized by the drone: this includes GPS, pathing, picture taking, data storage, networking and TCP/IP, a Java software …


Fine-Grained Multitask Allocation For Participatory Sensing With A Shared Budget, Jiangtao Wang, Yasha Wang, Daqing Zhang, Leye Wang, Haoyi Xiong, Abdelsalam Helal, Yuanduo He, Feng Wang Dec 2016

Fine-Grained Multitask Allocation For Participatory Sensing With A Shared Budget, Jiangtao Wang, Yasha Wang, Daqing Zhang, Leye Wang, Haoyi Xiong, Abdelsalam Helal, Yuanduo He, Feng Wang

Computer Science Faculty Research & Creative Works

For participatory sensing, task allocation is a crucial research problem that embodies a tradeoff between sensing quality and cost. An organizer usually publishes and manages multiple tasks utilizing one shared budget. Allocating multiple tasks to participants, with the objective of maximizing the overall data quality under the shared budget constraint, is an emerging and important research problem. We propose a fine-grained multitask allocation framework (MTPS), which assigns a subset of tasks to each participant in each cycle. Specifically, considering the user burden of switching among varying sensing tasks, MTPS operates on an attention-compensated incentive model where, in addition to the …


Designing A Datawarehousing And Business Analytics Course Using Experiential Learning Pedagogy, Gottipati Swapna, Venky Shankararaman Dec 2016

Designing A Datawarehousing And Business Analytics Course Using Experiential Learning Pedagogy, Gottipati Swapna, Venky Shankararaman

Research Collection School Of Computing and Information Systems

Experiential learning refers to learning from experience or learning by doing. Universities have explored various forms for implementing experiential learning such as apprenticeships, internships, cooperative education, practicums, service learning, job shadowing, fellowships and community activities. However, very little has been done in systematically trying to integrate experiential learning to the main stream academic curriculum. Over the last two years, at the authors’ university, a new program titled UNI-X was launched to achieve this. Combining academic curriculum with experiential learning pedagogy, provides a challenging environment for students to use their disciplinary knowledge and skills to tackle real world problems and issues …


Unsupervised Feature Selection For Outlier Detection By Modelling Hierarchical Value-Feature Couplings, Guansong Pang, Longbing Cao, Ling Chen, Huan Liu Dec 2016

Unsupervised Feature Selection For Outlier Detection By Modelling Hierarchical Value-Feature Couplings, Guansong Pang, Longbing Cao, Ling Chen, Huan Liu

Research Collection School Of Computing and Information Systems

Proper feature selection for unsupervised outlier detection can improve detection performance but is very challenging due to complex feature interactions, the mixture of relevant features with noisy/redundant features in imbalanced data, and the unavailability of class labels. Little work has been done on this challenge. This paper proposes a novel Coupled Unsupervised Feature Selection framework (CUFS for short) to filter out noisy or redundant features for subsequent outlier detection in categorical data. CUFS quantifies the outlierness (or relevance) of features by learning and integrating both the feature value couplings and feature couplings. Such value-to-feature couplings capture intrinsic data characteristics and …


Metroeye: Smart Tracking Your Metro Rips Underground, Weixi Gu, Ming Jin, Zimu Zhou, Costas J. Spanos, Lin Zhang Dec 2016

Metroeye: Smart Tracking Your Metro Rips Underground, Weixi Gu, Ming Jin, Zimu Zhou, Costas J. Spanos, Lin Zhang

Research Collection School Of Computing and Information Systems

Metro has become the first choice of traveling for tourists and citizens in metropolis due to its efficiency and convenience. Yet passengers have to rely on metro broadcasts to know their locations because popular localization services (e.g. GPS and wireless localization technologies) are often inaccessible underground. To this end, we propose MetroEye, an intelligent smartphone-based tracking system for metro passengers underground. MetroEye leverages low-power sensors embedded in modern smartphones to record ambient contextual features, and infers the state of passengers (Stop, Running, and Interchange) during an entire metro trip using a Conditional Random Field (CRF) model. MetroEye further provides arrival …


From Footprint To Evidence: An Exploratory Study Of Mining Social Data For Credit Scoring, Guangming Guo, Feida Zhu, Enhong Chen, Qi Liu, Le Wu, Chu Guan Dec 2016

From Footprint To Evidence: An Exploratory Study Of Mining Social Data For Credit Scoring, Guangming Guo, Feida Zhu, Enhong Chen, Qi Liu, Le Wu, Chu Guan

Research Collection School Of Computing and Information Systems

With the booming popularity of online social networks like Twitter and Weibo, online user footprints are accumulating rapidly on the social web. Simultaneously, the question of how to leverage the large-scale user-generated social media data for personal credit scoring comes into the sight of both researchers and practitioners. It has also become a topic of great importance and growing interest in the P2P lending industry. However, compared with traditional financial data, heterogeneous social data presents both opportunities and challenges for personal credit scoring. In this article, we seek a deep understanding of how to learn users’ credit labels from social …


Applying Ahp And Clustering Approaches For Public Transportation Decisionmaking: A Case Study Of Isfahan City, Alireza Salavati, Hossein Haghshenas, Bahador Ghadirifaraz, Jamshid Laghaei, Ghodrat Eftekhari Dec 2016

Applying Ahp And Clustering Approaches For Public Transportation Decisionmaking: A Case Study Of Isfahan City, Alireza Salavati, Hossein Haghshenas, Bahador Ghadirifaraz, Jamshid Laghaei, Ghodrat Eftekhari

Journal of Public Transportation

The main purpose of this paper is to define appropriate criteria for the systematic approach to evaluate and prioritize multiple candidate corridors for public transport investment simultaneously to serve travel demand, regarding supply of current public transportation system and road network conditions of Isfahan, Iran. To optimize resource allocation, policymakers need to identify proper corridors to implement a public transportation system. In fact, the main question is to adopt the best public transportation system for each main corridor of Isfahan. In this regard, 137 questionnaires were completed by experts, directors, and policymakers of Isfahan to identify goals and objectives in …


Qos And Trust Prediction Framework For Composed Distributed Systems, Dimuthu Undupitiya Gamage Dec 2016

Qos And Trust Prediction Framework For Composed Distributed Systems, Dimuthu Undupitiya Gamage

Open Access Dissertations

The objective of this dissertation is to propose a comprehensive framework to predict the QoS and trust (i.e, the degree of compliance of a service to its specification) values of composed distributed systems created out of existing quality-aware services. We improve the accuracy of the predictions by building context-aware models and validating them with real-life case studies. The context is the set of environmental factors that affect QoS attributes (such as response time and availability), and trust of a service or a composed system. The proposed framework uses available context-QoS dependency information of individual services and information about the interaction …


Predicting Malignant Nodules From Screening Ct Scans, Samuel Hawkins, Hua Wang, Ying Liu, Alberto Garcia, Olya Stringfield, Henry Krewer, Qiang Li, Dmitry Cherezov, Matthew Schabath, Lawrence O. Hall, Robert J. Gillies Dec 2016

Predicting Malignant Nodules From Screening Ct Scans, Samuel Hawkins, Hua Wang, Ying Liu, Alberto Garcia, Olya Stringfield, Henry Krewer, Qiang Li, Dmitry Cherezov, Matthew Schabath, Lawrence O. Hall, Robert J. Gillies

Computer Science and Engineering Faculty Publications

Objectives

The aim of this study was to determine whether quantitative analyses (“radiomics”) of low-dose computed tomography lung cancer screening images at baseline can predict subsequent emergence of cancer.

Methods

Public data from the National Lung Screening Trial (ACRIN 6684) were assembled into two cohorts of 104 and 92 patients with screen-detected lung cancer and then matched with cohorts of 208 and 196 screening subjects with benign pulmonary nodules. Image features were extracted from each nodule and used to predict the subsequent emergence of cancer.

Results

The best models used 23 stable features in a random forests classifier and could …