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Foreign Library Interface, Daniel Adler 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, Timothy T. Bergsma, Michael S. Smith 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, Duc Minh LUU, Ee Peng LIM, Tuan Anh HOANG, Chong Tat Freddy CHUA 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, Tuan-Anh HOANG, Ee Peng LIM 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, Jisun AN, Meeyoung CHA, GUMMADI, Krishna, Jon CROWCROFT, Daniele QUERIA 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, Kristen Johnson 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, Junyi Wang 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, Heasoo HWANG, Hady W. LAUW, Lise GETOOR, Alexandros NTOULAS 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, Atul Sancheti, Puneet Lakhanpal, Sergio Contreras, Pushkin Kachroo, Masha Wilson 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, Yiu On Li, Christopher Chan 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, David F. DiCarlo 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 …


Obfuscating The Topical Intention In Enterprise Text Search, Hwee Hwa PANG, Xiaokui XIAO, Jialie SHEN 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 …


Mining Social Dependencies In Dynamic Interaction Networks, Freddy Chong-Tat CHUA, Hady W. LAUW, Ee Peng LIM 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 …


Preconditioning Visco-Resistive Mhd For Tokamak Plasmas, Daniel R. Reynolds, Ravi Samtaney, Hilari C. Tiedeman 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, Zhongmei Yao, Daren B. H. Cline, Dmitri Loguinov 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, Ken C. K. LEE, Wang-Chien LEE, Baihua ZHENG, Yuan TIAN 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 …


Hierarchical Fuzzy Logic System For Implementing Maintenance Schedules Of Offshore Power Systems, C. S. CHANG, Zhaoxia WANG, Fan YANG, W. W. TAN 2012 Singapore Management University

Hierarchical Fuzzy Logic System For Implementing Maintenance Schedules Of Offshore Power Systems, C. S. Chang, Zhaoxia Wang, Fan Yang, W. W. Tan

Research Collection School Of Computing and Information Systems

Smart grid provides the technology for modernizing electricity delivery systems by using distributed and computer-based remote sensing, control and automation, and two-way communications. Potential benefits of the technology are that the smart grid's central control will now be able to control and operate many remote power plant, optimize the overall asset utilization and operational efficiently. In this paper, we propose an innovative approach for the smart grid to handle uncertainties arising from condition monitoring and maintenance of power plant. The approach uses an adaptive maintenance advisor and a system-maintenance optimizer for designing/implementing optimized condition-based maintenance activities, and collectively handles operational …


Quality And Leniency In Online Collaborative Rating Systems, Hady W. LAUW, Ee Peng LIM, Ke WANG 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 …


Block Preconditioning Of Stiff Implicit Models For Radiative Ionization In The Early Universe, Daniel R. Reynolds, Robert Harkness, Geoffrey So, Michael L. Norman 2012 Southern Methodist University

Block Preconditioning Of Stiff Implicit Models For Radiative Ionization In The Early Universe, Daniel R. Reynolds, Robert Harkness, Geoffrey So, Michael L. Norman

Mathematics Research

No abstract provided.


Achieving Both Valid And Secure Logistic Regression Analysis On Aggregated Data From Different Private Sources, Yuval Nardi, Stephen FIENBERG, Robert J. HALL 2012 Singapore Management University

Achieving Both Valid And Secure Logistic Regression Analysis On Aggregated Data From Different Private Sources, Yuval Nardi, Stephen Fienberg, Robert J. Hall

LARC Research Publications

Preserving the privacy of individual databases when carrying out statistical calculations has a relatively long history in statistics and had been the focus of much recent attention in machine learning. In this paper, we present a protocol for fitting a logistic regression when the data are held by separate parties - without actually combining information sources - by exploiting results from the literature on multi-party secure computation. Our protocol provides only the final result of the calculation compared with other methods that share intermediate values and thus present an opportunity for compromise of values in the individual databases. Our paper …


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