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Full-Text Articles in Physical Sciences and Mathematics

Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang Nov 2006

Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang

Computer Science Faculty Publications

Previous analytical results on the resilience of unstructured P2P systems have not explicitly modeled heterogeneity of user churn (i.e., difference in online behavior) or the impact of in-degree on system resilience. To overcome these limitations, we introduce a generic model of heterogeneous user churn, derive the distribution of the various metrics observed in prior experimental studies (e.g., lifetime distribution of joining users, joint distribution of session time of alive peers, and residual lifetime of a randomly selected user), derive several closed-form results on the transient behavior of in-degree, and eventually obtain the joint in/out degree isolation probability as a simple …


Scalable Approaches For Supporting Mpi-Io Atomicity, Peter Aarestad, George K. Thiruvathukal, Avery Ching, Alok Choudhary May 2006

Scalable Approaches For Supporting Mpi-Io Atomicity, Peter Aarestad, George K. Thiruvathukal, Avery Ching, Alok Choudhary

Computer Science: Faculty Publications and Other Works

Scalable atomic and parallel access to noncontiguous regions of a file is essential to exploit high performance I/O as required by large-scale applications. Parallel I/O frameworks such as MPI I/O conceptually allow I/O to be defined on regions of a file using derived datatypes. Access to regions of a file can be automatically computed on a perprocessor basis using the datatype, resulting in a list of (offset, length) pairs. We describe three approaches for implementing lock serving (whole file, region locking, and byterange locking) and compare the various approaches using three noncontiguous I/O benchmarks. We present the details of the …


The Hydra Filesystem: A Distrbuted Storage Famework, Benjamin Gonzalez, George K. Thiruvathukal Jan 2006

The Hydra Filesystem: A Distrbuted Storage Famework, Benjamin Gonzalez, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

Hydra File System (HFS) is an experimental framework for constructing parallel and distributed filesystems. While parallel and distributed applications requiring scalable and flexible access to storage and retrieval are becoming more commonplace, parallel and distributed filesystems remain difficult to deploy easily and configure for different needs. HFS aims to be different by being true to the tradition of high-performance computing while employing modern design patterns to allow various policies to be configured on a per instance basis (e.g. storage, communication, security, and indexing schemes). We describe a working prototype (available for public download) that has been implemented in the Python …


Journey To The Center Of The Core: Computers And The Internet In The Core Curriculum, Jorge Pérez, Meg C. Murray Jan 2006

Journey To The Center Of The Core: Computers And The Internet In The Core Curriculum, Jorge Pérez, Meg C. Murray

Faculty and Research Publications

Computers, digitalization and the Internet have transformed modern society. Commerce, education, communication and socialization will never be the same. Surprisingly, many universities do not require a computing course in the core curriculum. Critical information technology (IT) competencies are often taken for granted, to the detriment of students who lack computing and Internet skills. This paper describes an initiative undertaken by a computer science and information systems department to assess and remediate IT skills needed by all university students, regardless of major. The project is evolving along several dimensions: identification of discipline-independent IT competencies, assessment of IT skills among current and …


Rhode Island College Mobile Course Catalog, Lianne Elsner Jan 2006

Rhode Island College Mobile Course Catalog, Lianne Elsner

Honors Projects

Consists of a suite of computer programs written in Visual Basic.net and embedded Visual Basic 3.0, whose purpose is to display the RIC course catalog on a Pocket PC device running Windows Mobile. The program package allows major course requirements and information to be viewed on a single screen. Included is a desktop computer program which allows faculty and staff to make changes to the database of courses.