Marss: Multivariate Autoregressive State-Space Models For Analyzing Time-Series Data,
2012
Northwest Fisheries Science Center
Marss: Multivariate Autoregressive State-Space Models For Analyzing Time-Series Data, Elizabeth E. Holmes, Eric J. Ward, Kellie Wills
The R Journal
MARSS is a package for fitting multivariate autoregressive state-space models to time-series data. The MARSS package implements state-space models in a maximum likelihood framework. The core functionality of MARSSis based on likelihood maximization using the Kalman filter/smoother, combined with an EM algorithm. To make comparisons with other packages available, parameter estimation is also permitted via direct search routines avail able in ’optim’. The MARSS package allows data to contain missing values and allows a wide variety of model structures and constraints to be specified (such as fixed or shared parameters). In addition to model-fitting, the package provides bootstrap routines for …
Vdgraph: A Package For Creating Variance Dispersion Graphs,
2012
Brigham Young University
Vdgraph: A Package For Creating Variance Dispersion Graphs, John Lawson
The R Journal
This article introduces the package Vdgraph that is used form a king variance dispersion graphs of response surface designs.The package includes functions that make the variance dispersion graph of one design or compare variance dispersion graphs of two designs, which are stored in data frames or matrices.The package also contains several minimum run response surface designs (stored as matrices) that are not available in other R packages.
Analysing Seasonal Data,
2012
Queensland University of Technology
Analysing Seasonal Data, Adrian G. Barnett, Peter Baker, Annette J. Dobson
The R Journal
Many common diseases, such as the flu and cardiovascular disease, increase markedly in winter and dip in summer. These seasonal patterns have been part of life for millennia and were first noted in ancient Greece by both Hippocrates and Herodotus. Recent interest has focused on climate change, and the concern that seasons will become more extreme with harsher winter and summer weather. We describe a set of R functions designed to model seasonal pat terns in disease. We illustrate some simple descriptive and graphical methods, a more complex method that is able to model non-stationary patterns, and the case-crossover to …
Foreign Library Interface,
2012
Georg-August Universität
Foreign Library Interface, Daniel Adler
The R Journal
We present an improved Foreign Function Interface (FFI) for R to call arbitary native functions without the need for C wrapper code. Further we discuss a dynamic linkage framework for binding standard C libraries to R across platforms using a universal type information format. The package rdyncall comprises the framework and an initial repository of cross platform bindings for standard libraries such as (legacy and modern) OpenGL, the family of SDL libraries and Expat. The package enables system level programming using the R language; sample applications are given in the article. We out line the underlying automation tool-chain that extracts …
Sumo: An Authenticating Web Application With An Embedded R Session,
2012
Metrum Research Group LLC
Sumo: An Authenticating Web Application With An Embedded R Session, Timothy T. Bergsma, Michael S. Smith
The R Journal
Sumo is a web application intended as a template for developers. It is distributed as a Java ‘war’ file that deploys automatically when placed in a Servlet container’s ‘webapps’ directory. If a user supplies proper credentials, Sumocreates a session-specific Secure Shell connection to the host and a user-specific R session over that connection. Developers may write dynamic server pages that make use of the persistent R session and user-specific file space. The supplied example plots a data set conditional on preferences indicated by the user; it also displays some static text. A companion server page al lows the user to …
Modeling Diffusion In Social Networks Using Network Properties,
2012
Singapore Management University
Modeling Diffusion In Social Networks Using Network Properties, Duc Minh Luu, Ee Peng Lim, Tuan Anh Hoang, Chong Tat Freddy Chua
Research Collection School Of Computing and Information Systems
"Diffusion of items occurs in social networks due to spreading of items through word of mouth and exogenous factors. These items may be news, products, videos, advertisements or contagious viruses. When a user purchases or consumes one of such items, we say that she adopts the item and she becomes an item adopter. Previous research has studied diffusion process at both the macro and micro levels. The former models the number of item adopters in the diffusion process while the latter determines which individuals adopt item. Both macro and micro level models have their merits and limitations. In this paper, …
Virality And Susceptibility In Information Diffusions,
2012
Singapore Management University
Virality And Susceptibility In Information Diffusions, Tuan-Anh Hoang, Ee Peng Lim
Research Collection School Of Computing and Information Systems
Viral diffusion allows a piece of information to widely and quickly spread within the network of users through word-ofmouth. In this paper, we study the problem of modeling both item and user factors that contribute to viral diffusion in Twitter network. We identify three behaviorial factors, namely user virality, user susceptibility and item virality, that contribute to viral diffusion. Instead of modeling these factors independently as done in previous research, we propose a model that measures all the factors simultaneously considering their mutual dependencies. The model has been evaluated on both synthetic and real datasets. The experiments show that our …
Visualizing Media Bias Through Twitter,
2012
Singapore Management University
Visualizing Media Bias Through Twitter, Jisun An, Meeyoung Cha, Gummadi, Krishna, Jon Crowcroft, Daniele Queria
Research Collection School Of Computing and Information Systems
Traditional media outlets are known to report political news in a biased way, potentially affecting the political beliefs of the audience and even altering their voting behaviors. Therefore, tracking bias in everyday news and building a platform where people can receive balanced news information is important. We propose a model that maps the news media sources along a dimensional dichotomous political spectrum using the co-subscriptions relationships inferred by Twitter links. By analyzing 7 million follow links, we show that the political dichotomy naturally arises on Twitter when we only consider direct media subscription. Furthermore, we demonstrate a real-time Twitter-based application …
Software For Estimation Of Human Transcriptome Isoform Expression Using Rna-Seq Data,
2012
LSU New Orleans
Software For Estimation Of Human Transcriptome Isoform Expression Using Rna-Seq Data, Kristen Johnson
LSU New Orleans Theses and Dissertations
The goal of this thesis research was to develop software to be used with RNA-Seq data for transcriptome quantification that was capable of handling multireads and quantifying isoforms on a more global level. Current software available for these purposes uses various forms of parameter alteration in order to work with multireads. Many still analyze isoforms per gene or per researcher determined clusters as well. By doing so, the effects of multireads are diminished or possibly wrongly represented. To address this issue, two programs, GWIE and ChromIE, were developed based on a simple iterative EM-like algorithm with no parameter manipulation. These …
A Normal Truncated Skewed-Laplace Model In Stochastic Frontier Analysis,
2012
Western Kentucky University
A Normal Truncated Skewed-Laplace Model In Stochastic Frontier Analysis, Junyi Wang
Masters Theses & Specialist Projects
Stochastic frontier analysis is an exciting method of economic production modeling that is relevant to hospitals, stock markets, manufacturing factories, and services. In this paper, we create a new model using the normal distribution and truncated skew-Laplace distribution, namely the normal-truncated skew-Laplace model. This is a generalized model of the normal-exponential case. Furthermore, we compute the true technical efficiency and estimated technical efficiency of the normal-truncated skewed-Laplace model. Also, we compare the technical efficiencies of normal-truncated skewed-Laplace model and normal-exponential model.
Organizing User Search Histories,
2012
Singapore Management University
Organizing User Search Histories, Heasoo Hwang, Hady W. Lauw, Lise Getoor, Alexandros Ntoulas
Research Collection School Of Computing and Information Systems
Users are increasingly pursuing complex task-oriented goals on the web, such as making travel arrangements, managing finances, or planning purchases. To this end, they usually break down the tasks into a few codependent steps and issue multiple queries around these steps repeatedly over long periods of time. To better support users in their long-term information quests on the web, search engines keep track of their queries and clicks while searching online. In this paper, we study the problem of organizing a user's historical queries into groups in a dynamic and automated fashion. Automatically identifying query groups is helpful for a …
Comparative Study Of Various Data Collection Software Used For Seat-Belt Observation Surveys,
2012
University of Nevada, Las Vegas
Comparative Study Of Various Data Collection Software Used For Seat-Belt Observation Surveys, Atul Sancheti, Puneet Lakhanpal, Sergio Contreras, Pushkin Kachroo, Masha Wilson
College of Engineering: Graduate Celebration Programs
Every year, Click It or Ticket (CIOT) mobilization is held in U.S. which aims at increasing seat-belt usage awareness among the people. Data collection for assessing current seat-belt usage rates and campaign design for influencing mass audience are the two most important components of the mobilization. This paper presents a comparative study of various data collections software used for seat-belt observational surveys. The comparison is based on the speed and accuracy of the data collected from different software at the same locations and at the same time of the day.
User Behaviour In The Webpac: Insights From Google Analytics,
2012
Hong Kong Baptist University
User Behaviour In The Webpac: Insights From Google Analytics, Yiu On Li, Christopher Chan
Hong Kong Innovative Users Group Meetings
No abstract provided.
Random Number Generation: Types And Techniques,
2012
Liberty University
Random Number Generation: Types And Techniques, David F. Dicarlo
Senior Honors Theses
What does it mean to have random numbers? Without understanding where a group of numbers came from, it is impossible to know if they were randomly generated. However, common sense claims that if the process to generate these numbers is truly understood, then the numbers could not be random. Methods that are able to let their internal workings be known without sacrificing random results are what this paper sets out to describe. Beginning with a study of what it really means for something to be random, this paper dives into the topic of random number generators and summarizes the key …
Mining Social Dependencies In Dynamic Interaction Networks,
2012
Singapore Management University
Mining Social Dependencies In Dynamic Interaction Networks, Freddy Chong-Tat Chua, Hady W. Lauw, Ee Peng Lim
Research Collection School Of Computing and Information Systems
User-to-user interactions have become ubiquitous in Web 2.0. Users exchange emails, post on newsgroups, tag web pages, co-author papers, etc. Through these interactions, users co-produce or co-adopt content items (e.g., words in emails, tags in social bookmarking sites). We model such dynamic interactions as a user interaction network, which relates users, interactions, and content items over time. After some interactions, a user may produce content that is more similar to those produced by other users previously. We term this effect social dependency, and we seek to mine from such networks the degree to which a user may be socially dependent …
Obfuscating The Topical Intention In Enterprise Text Search,
2012
Singapore Management University
Obfuscating The Topical Intention In Enterprise Text Search, Hwee Hwa Pang, Xiaokui Xiao, Jialie Shen
Research Collection School Of Computing and Information Systems
The text search queries in an enterprise can reveal the users' topic of interest, and in turn confidential staff or business information. To safeguard the enterprise from consequences arising from a disclosure of the query traces, it is desirable to obfuscate the true user intention from the search engine, without requiring it to be re-engineered. In this paper, we advocate a unique approach to profile the topics that are relevant to the user intention. Based on this approach, we introduce an (ε 1, ε 2)-privacy model that allows a user to stipulate that topics relevant to her intention …
Preconditioning Visco-Resistive Mhd For Tokamak Plasmas,
2012
Southern Methodist University
Preconditioning Visco-Resistive Mhd For Tokamak Plasmas, Daniel R. Reynolds, Ravi Samtaney, Hilari C. Tiedeman
Mathematics Research
No abstract provided.
On Superposition Of Heterogeneous Edge Processes In Dynamic Random Graphs,
2012
University of Dayton
On Superposition Of Heterogeneous Edge Processes In Dynamic Random Graphs, Zhongmei Yao, Daren B. H. Cline, Dmitri Loguinov
Computer Science Faculty Publications
This paper builds a generic modeling framework for analyzing the edge-creation process in dynamic random graphs in which nodes continuously alternate between active and inactive states, which represent churn behavior of modern distributed systems. We prove that despite heterogeneity of node lifetimes, different initial out-degree, non-Poisson arrival/failure dynamics, and complex spatial and temporal dependency among creation of both initial and replacement edges, a superposition of edge-arrival processes to a live node under uniform selection converges to a Poisson process when system size becomes sufficiently large. Due to the convoluted dependency and non-renewal nature of various point processes, this result significantly …
Road: A New Spatial Object Search Framework For Road Networks,
2012
University of Massachusetts Dartmouth
Road: A New Spatial Object Search Framework For Road Networks, Ken C. K. Lee, Wang-Chien Lee, Baihua Zheng, Yuan Tian
Research Collection School Of Computing and Information Systems
In this paper, we present a new system framework called ROAD for spatial object search on road networks. ROAD is extensible to diverse object types and efficient for processing various location-dependent spatial queries (LDSQs), as it maintains objects separately from a given network and adopts an effective search space pruning technique. Based on our analysis on the two essential operations for LDSQ processing, namely, network traversal and object lookup, ROAD organizes a large road network as a hierarchy of interconnected regional subnetworks (called Rnets). Each Rnet is augmented with 1) shortcuts and 2) object abstracts to accelerate network traversals and …
Quality And Leniency In Online Collaborative Rating Systems,
2012
Singapore Management University
Quality And Leniency In Online Collaborative Rating Systems, Hady W. Lauw, Ee Peng Lim, Ke Wang
Research Collection School Of Computing and Information Systems
The emerging trend of social information processing has resulted in Web users’ increased reliance on user-generated content contributed by others for information searching and decision making. Rating scores, a form of user-generated content contributed by reviewers in online rating systems, allow users to leverage others’ opinions in the evaluation of objects. In this article, we focus on the problem of summarizing the rating scores given to an object into an overall score that reflects the object’s quality. We observe that the existing approaches for summarizing scores largely ignores the effect of reviewers exercising different standards in assigning scores. Instead of …
