Computer Sciences Commons^™

Bsgs: Bayesian Sparse Group Selection, Kuo-Jung Lee, Ray-Bing Chen

The R Journal

An R package BSGS is provided for the integration of Bayesian variable and sparse group selection separately proposed by Chen et al. (2011) and Chen et al. (in press) for variable selection problems, even in the cases of large p and small n. This package is designed for variable selection problems including the identification of the important groups of variables and the active variables within the important groups. This article introduces the functions in the BSGS package that can be used to perform sparse group selection as well as variable selection through simulation studies and real data.

Srcs: Statistical Ranking Color Scheme For Visualizing Parameterized Multiple Pairwise Comparisons With R, Pablo J. Villacorta, José A. Sáez

The R Journal

The problem of comparing a new solution method against existing ones to find statistically significant differences arises very often in sciences and engineering. When the problem instance being solved is defined by several parameters, assessing a number of methods with respect to many problem configurations simultaneously becomes a hard task. Some visualization technique is required for presenting a large number of statistical significance results in an easily interpretable way. Here we review an existing color-based approach called Statistical Ranking Color Scheme (SRCS) for displaying the results of multiple pairwise statistical comparisons between several methods assessed separately on a number of …

Zoib: An R Package For Bayesian Inference For Beta Regression And Zero/One Inflated Beta Regression, Fang Liu, Yunchuan Kong

The R Journal

The beta distribution is a versatile function that accommodates a broad range of probability distribution shapes. Beta regression based on the beta distribution can be used to model a response variable y that takes values in open unit interval (0,1). Zero/one inflated beta (ZOIB) regression models can be applied when y takes values from closed unit interval [0,1]. The ZOIB model is based a piecewise distribution that accounts for the probability mass at 0 and 1, in addition to the probability density within (0,1). This paper introduces an R package– zoib that provides Bayesian inferences for a class of ZOIB …

Fitting Conditional And Simultaneous Autoregressive Spatial Models In Hglm, Moudud Alam, Lars Rönnegård, Xia Shen

The R Journal

We present a new version ( 2.0) of the hglm package for fitting hierarchical generalized linear models (HGLMs) with spatially correlated random effects. CAR() and SAR() families for con ditional and simultaneous autoregressive random effects were implemented. Eigen decomposition of the matrix describing the spatial structure (e.g., the neighborhood matrix) was used to transform the CAR/SARrandomeffects into an independent, but heteroscedastic, Gaussian random effect. A linear predictor is fitted for the random effect variance to estimate the parameters in the CAR and SAR models. This gives a computationally efficient algorithm for moderately sized problems.

Vsurf: An R Package For Variable Selection Using Random Forests, Robin Genuer, Jean-Michel Poggi, Christine Tuleau-Malot

The R Journal

This paper describes the R package VSURF. Based on random forests, and for both regression and classification problems, it returns two subsets of variables. The first is a subset of important variables including some redundancy which can be relevant for interpretation, and the second one is a smaller subset corresponding to a model trying to avoid redundancy focusing more closely on the prediction objective. The two-stage strategy is based on a preliminary ranking of the explanatory variables using the random forests permutation-based score of importance and proceeds using a stepwise forward strategy for variable introduction. The two proposals can …

Generalized Hermite Distribution Modelling With The R Package Hermite, David Moriña, Manuel Higueras, Pedro Puig, María Oliveira

The R Journal

The Generalized Hermite distribution (and the Hermite distribution as a particular case) is often used for fitting count data in the presence of over-dispersion or multimodality. Despite this, to our knowledge, no standard software packages have implemented specific functions to compute basic probabilities and make simple statistical inference based on these distributions. We present here a set of computational tools that allows the user to face these difficulties by modelling with the Generalized Hermite distribution using the R package hermite. The package can also be used to generate random deviates from a Generalized Hermite distribution and to use basic …

Working With Multilabel Datasets In R: The Mldr Package, Francisco Charte, David Charte

The R Journal

Most classification algorithms deal with datasets which have a set of input features, the variables to be used as predictors, and only one output class, the variable to be predicted. However, in late years many scenarios in which the classifier has to work with several outputs have come to life. Automatic labeling of text documents, image annotation or protein classification are among them. Multilabel datasets are the product of these new needs, and they have many specific traits. The mldr package allows the user to load datasets of this kind, obtain their characteristics, produce specialized plots, and manipulate them. The …

Numerical Evaluation Of The Gauss Hypergeometric Function With The Hypergeo Package, Robin K. S. Hankin

The R Journal

This paper introduces the hypergeo package of R routines for numerical calculation of hypergeometric functions. The package is focussed on efficient and accurate evaluation of the Gauss hypergeometric function over the whole of the complex plane within the constraints of fixed-precision arithmetic. The hypergeometric series is convergent only within the unit circle, so analytic continuation must be used to define the function outside the unit circle. This short document outlines the numerical and conceptual methods used in the package; and justifies the package philosophy, which is to maintain transparent and verifiable links between the software and Abramowitz and Stegun (1965). …

Treeclust: An R Package For Tree-Based Clustering Dissimilarities, Samuel E. Buttrey, Lyn R. Whitaker

The R Journal

This paper describes treeClust, an R package that produces dissimilarities useful for clustering. These dissimilarities arise from a set of classification or regression trees, one with each variable in the data acting in turn as a the response, and all others as predictors. This use of trees produces dissimilarities that are insensitive to scaling, benefit from automatic variable selection, and appear to perform well. The software allows a number of options to be set, affecting the set of objects returned in the call; the user can also specify a clustering algorithm and, optionally, return only the clustering vector. The …

Apc: An R Package For Age-Period-Cohort Analysis, Bent Nielsen

The R Journal

The apc package includes functions for age-period-cohort analysis based on the canonical parametrisation of Kuang et al. (2008a). The package includes functions for organizing the data, descriptive plots, a deviance table, estimation of (sub-models of) the age-period-cohort model, a plot for specification testing, plots of estimated parameters, and sub-sample analysis.

News From The Bioconductor Project, The Bioconductor Team

The R Journal

The Bioconductor project provides tools for the analysis and comprehension of high throughput genomic data. The 1104 software packages available in Bioconductor can be viewed at http://bioconductor.org/packages/. Navigate packages using ‘biocViews’ terms and title search. Each package has an html page with a description, links to vignettes, reference manuals, and usage statistics. Start using Bioconductor version 3.2 by installing R 3.2.3 and evaluating the commands

Editorial, Bettina Grün

The R Journal

On behalf of the editorial board, I am pleased to publish Volume 7, Issue 2 of the R Journal. This issue contains 20 contributed research articles and several contributions to the News and Notes section.

Code Profiling In R: A Review Of Existing Methods And An Introduction To Package Guiprofiler, Angel Rubio, Fernando De Villar

The R Journal

Code analysis tools are crucial to understand program behavior. Profile tools use the results of time measurements in the execution of a program to gain this understanding and thus help in the optimization of the code. In this paper, we review the different available packages to profile R code and show the advantages and disadvantages of each of them. In additon, we present GUIProfiler, a package that fulfills some unmet needs

Package GUIProfiler generates an HTML report with the timing for each code line and the relationships between different functions. This package mimics the behavior of the MATLAB profiler. …

Quantifquantile: An R Package For Performing Quantile Regression Through Optimal Quantization, Isabelle Charlier, Davy Paindaveine, Jérôme Saracco

The R Journal

In quantile regression, various quantiles of a response variable Y are modelled as functions of covariates (rather than its mean). An important application is the construction of reference curves/surfaces and conditional prediction intervals for Y. Recently, a nonparametric quantile regression method based on the concept of optimal quantization was proposed. This method competes very well with k-nearest neighbor, kernel, and spline methods. In this paper, we describe an R package, called QuantifQuantile, that allows to perform quantization-based quantile regression. We describe the various functions of the package and provide examples.

Changes In R, The R Core Team

The R Journal

CHANGES IN R 3.2.3

CHANGES IN R 3.2.2

The R Consortium And The R Foundation, Martyn Plummer

The R Journal

The R Consortium was announced at the useR! 2015 conference in Aalborg, Denmark on 30 June. It is a non-profit organization set up to provide infrastructure for the R community. The purpose of this article is to explain some of the background to the setting up of the Consortium and how it interacts with the R Foundation.

Siguria E Rrjetave Kompjuterike, Blinera Ahmeti

Theses and Dissertations

Shpërndarja e internetit në përmasa më të mëdha filloi në fillim të viteve 1980. Qysh në këtë fillim lindi edhe nevoja për sigurinë e rrjetave kompjuterike, menjëherë pas shfaqjes së sulmeve të para që shkaktuan dëme në informacionet dhe sistemet kompjuterike. Ndryshimet shumë të shpejta në botën e kompjuterikës, aplikacioneve mobile dhe rrjetave pa kabllo kanë ndryshuar plotësisht tiparet e sigurisë së rrjetave. Qysh nga ajo kohë, sado që ka pasur zhvillime tepër të mëdha në botën e internetit, ende ka shumë ngecje në zhvillimin e metodave të sigurisë së rrjetave.

Problemet me sigurinë më së lehti dhe më së …

Programimi Paralel Me Gpu, Kujtim Kërqeli

Theses and Dissertations

No abstract provided.

Implementimi Dhe Adaptimi I E-Commerce Në Kompanitë E Vogla Në Zvicër, Drilon Tahiri

Theses and Dissertations

Qëllimi i këtij hulumtimi është të shqyrtojë implementimin dhe adaptimin e e-commerce në kompanitë e vogla në Zvicër . Ky hulumtim përshkruan të gjitha përfitimet dhe pengesat me të cilat ballafaqohen kompanitë e vogla gjatë procesit të implementimit të e-commerce. Një hulumtim cilësor është kryer. Po ashtu është kryer edhe një intervistë me një menaxher të një kompanie të vogël në Zvicër.

Ky studim tregon se kompanitë e vogla në Zvicër kanë përparësi në implementimin dhe adaptimin e e-commerce në krahasim me vendet e tjera të Evropës, por ende ka pengesa të cilat mund të përmirësohen në të ardhmen.

Përfitimet …

Krahasimi I Teknologjive Për Implementimin Dhe Përkrahjen E Videove Në Ueb, Rinor Svarça

Theses and Dissertations

Në këtë punim diplome jemi munduar të analizojmë dy teknologjitë më të përdorura për lansimin e videove në internet Adobe Flash dhe HTML5, edhe pse nuk janë të ngjashme kanë të përbashkët mundësinë e shfaqjes së videove në ueb faqe, ku dhe jemi fokusuar më shumë në këtë të përbashkët të këtyre dy teknologjive. Gjithashtu kemi hulumtuar për historikun, zhvillimin, ngjashmëritë dhe dallimet që kanë, kemi analizuar edhe problemet e tye dhe si ka ardhur deri te zëvendësimi i Flash me HTML5 për një kohë mjaftë të shkurtër. Jemi munduar t’i krahasojmë të gjitha pjesët e përbashkëta dhe kemi paraqitur …

Zgjidhja E Problemeve Të Transportit Në Rrjetat Telekomunikuese Duke Kaluar Në Ran-In E Bazuar Në Ip, Meriton Ahmeti

Theses and Dissertations

Operimi i Radio paisjeve (Antenat) të operatorëve të ndryshëm të telefonisë mobile dhe ndërlidhja e tyre me Rrjetën Bërthamë (Core Network) mundësohet nga RAN (Radio Access Network) i cili jo domosdoshmërisht është i njejtë për operator të ndryshëm mobil.

Përgjatë viteve të zhvillimit të Telekomunikacionit në përgjithesi dhe të Komunikimeve mobile në veçanti, janë zhvilluar teknologji të reja për ta tejkalur problemin e diversitetit në mes të teknologjive të aplikuara në rrjetën e një operatori të telefonisë mobile por edhe për të tejkaluar kufizimet e ndryshme teknike.

Në aspektin e dizajnimit të rrjetës së operatorëve të telefonisë mobile gjithmonë kalimi …

Krahasimi I Cms Platformave, Wordpress Dhe Umbraco Për Ndërtimin E Ueb Faqeve Të Korporatave, Shpëtim Rashiti

Theses and Dissertations

Në ditët e sotme përdorimi i ueb faqeve është shëndruar në një element shumë të rendësishëm për çdo kompani apo korporat, ku për çdo njërën është e rëndësishme që të kenë një ueb faqe përmes së cilës do të mund të prezantonin punën e tyre apo të shisnin produkte online. Këto ueb faqe apo sisteme kanë mjaft shumë përmbajtje dhe kërkojnë punë për tu realizuar për këtë arsye është shumë e rëndësishme që këto ueb faqe të ndërtohen duke përdorur ndonjë CMS (Content Management System) Platformë. Në praktikë egsistojnë mjaft CMS platforma mirëpo në këtë punim ne do të krahasojmë …

Bl-Mle: Block-Level Message-Locked Encryption For Secure Large File Deduplication, Rongmao Chen, Yi Mu, Guomin Yang, Fuchun Guo

Research Collection School Of Computing and Information Systems

Deduplication is a popular technique widely used to save storage spaces in the cloud. To achieve secure deduplication of encrypted files, Bellare et al. formalized a new cryptographic primitive named message-locked encryption (MLE) in Eurocrypt 2013. Although an MLE scheme can be extended to obtain secure deduplication for large files, it requires a lot of metadata maintained by the end user and the cloud server. In this paper, we propose a new approach to achieve more efficient deduplication for (encrypted) large files. Our approach, named block-level message-locked encryption (BL-MLE), can achieve file-level and block-level deduplication, block key management, and proof …

A Misspecification Test For Logit Based Route Choice Models, Tien Mai, Emma Frejinger, Fabian Bastin

Research Collection School Of Computing and Information Systems

The multinomial logit (MNL) model is often used for analyzing route choices in real networks in spite of the fact that path utilities are believed to be correlated. Yet, statistical tests for model misspecification are rarely used. This paper shows how the information matrix test for model misspecification proposed byWhite (1982) can be applied to test path-based and link-based MNL route choice models.We present a Monte Carlo experiment using simulated data to assess the size and the power of the test and to compare its performance with the IIA (Hausman and McFadden, 1984) and McFadden–Train Lagrange multiplier (McFadden and Train, …

Mylife: An Online Personal Memory Album, Di Wang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

In this demo, we illustrate the formation, retrieval, and playback of autobiographical memory in an online personal memory album named MyLife. The memory in MyLife consists of pictorial snapshots of one's life together with the associated context, namely time, location, people, activity, imagery, and emotion. MyLife allows direct import of memories from other online personal photo repositories. For memory retrieval, users can use not only exact cues, but also partial, vague, inaccurate, and random ones. The retrieved memories are then played back as a movie-like slide show with various visual effects and background music. MyLife holds high potential in both …

Coordinated Persuasion With Dynamic Group Formation For Collaborative Elderly Care, Budhitama Subagdja, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Ageing in place demands a new paradigm of inhouse caregiving allowing many aspects of daily lives to be tackled by smart appliances and technologies. The important challenges include the effective provision of recommendations by multiple parties of caregiver constituting changes of the user’s behavior. In this multiagent environment, interdependencies between agents become major issues to tackle. This paper presents an approach of dynamic group formation for autonomous caregiving agents to collaborate in recommending different aspects of well-being. The approach supports the agents to regulate the timing of their recommendations, prevent conflicting messages, and cooperate to make more effective persuasions. A …

Adaptive Scaling Of Cluster Boundaries For Large-Scale Social Media Data Clustering, Lei Meng, Ah-Hwee Tan, Donald C. Wunsch

Research Collection School Of Computing and Information Systems

The large scale and complex nature of social media data raises the need to scale clustering techniques to big data and make them capable of automatically identifying data clusters with few empirical settings. In this paper, we present our investigation and three algorithms based on the fuzzy adaptive resonance theory (Fuzzy ART) that have linear computational complexity, use a single parameter, i.e., the vigilance parameter to identify data clusters, and are robust to modest parameter settings. The contribution of this paper lies in two aspects. First, we theoretically demonstrate how complement coding, commonly known as a normalization method, changes the …

A Layered Hidden Markov Model For Predicting Human Trajectories In A Multi-Floor Building, Qian Li, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Tracking and modeling huge amount of users’ movement in a multi-floor building by using wireless devices is a challenging task, due to crowd movement complexity and signal sensing accuracy. In this paper, we use Layered Hidden Markov Model (LHMM) to fit the spatial-temporal trajectories (with large number of missing values). We decompose the problem into distinct layers that Hidden Markov Models (HMMs) are operated at different spatial granularities separately. Baum-Welch algorithm and Viterbi algorithm are used for finding the probable location sequences at each layer. By measuring the predicted result of trajectories, we compared the predicted results of both single …

Modeling Social Media Content With Word Vectors For Recommendation, Ying Ding, Jing Jiang

Research Collection School Of Computing and Information Systems

In social media, recommender systems are becoming more and more important. Different techniques have been designed for recommendations under various scenarios, but many of them do not use user-generated content, which potentially reflects users’ opinions and interests. Although a few studies have tried to combine user-generated content with rating or adoption data, they mostly reply on lexical similarity to calculate textual similarity. However, in social media, a diverse range of words is used. This renders the traditional ways of calculating textual similarity ineffective. In this work, we apply vector representation of words to measure the semantic similarity between text. We …

On Neighborhood Effects In Location-Based Social Networks, Thanh-Nam Doan, Freddy Chong-Tat Chua, Ee-Peng Lim

Research Collection School Of Computing and Information Systems

In this paper, we analyze factors that determine the check-in decisions of users on venues using a location-based social network dataset. Based on a Foursquare dataset constructed from Singapore-based users, we devise a stringent criteria to identify the actual home locations of a subset of users. Using these users' check-ins, we aim to ascertain the neighborhood effect on the venues visited, compared with the activity level of users. We further formulate the check-in count prediction and check-in prediction tasks. A comprehensive set of features have been defined and they encompass information from users, venues, their neighbors, and friendship networks. We …