5536996
DMAS: a web-based distributed mathematics assessment system (abstract only)
Assessing student performance and understanding is very important in education generally and in Mathematics education in particular. DMAS is a Web-based Distributed Mathematics Assessment system that can be of great value to teachers and students of Mathematics. Features of DMAS include: DMAD (the core Distributed Mathematics Assessment database), test authoring tool for teachers, online taking of tests, grading and results administration, comprehension diagnoses and linking to remedial materials. DMAS supports many problem types and allows mathematical formulas/expressions as well as geometry drawings/graphs to be part of questions and answers. Furthermore, DMAS supports the use of test taking as a teaching method. A teacher can monitor all students from the teacher terminal in real-time and either verbally guide the whole class on certain points or interact privately with one or more students via the Teacher-Student Interaction Mechanism (TSIM), an instant text-messaging provided by DMAS. A new Assessment Markup Language, MAML, is designed to make tests and test questions easy to share widely on the Web. Although developed as a sub-system of WME (Web-based Mathematics Education), DMAS is an independent Web system easily interfaced to any Web page through a well-defined API. The DMAS system consists of local databases at individual school websites. Teachers may publish new or improved questions to their local DMAS database to be shared with other teachers in the same school and in different schools. Teachers can use the powerful search engine (DMASEngine) to search for assessment questions. Search can be narrowed by subject, topic, grade-level, question type, keyword, and author. DMAD is designed to work as one distributed database while providing power, unity, and convenience at each participating school. The system helps create, revise, administer, and grade exams that can contain various types of questions: multiple choices, true-or-false, extended (essay) questions, short answers, two-columns matching, and fill-the-blank. Questions use a well-designed representation (encoding) allowing correct answers, rubrics, formulas, images, geometrical objects (SVG), and multimedia as well as interactive contents. DMAS system provides different views (modes): teacher and student modes. It also supports two types of testing: online and paper testing. The teacher can set Assessment test display options: display questions by a given order, by random questions none-random options, or by all questions/options are in random order. Tests taken online can be graded automatically and stored for teacher review, analysis, and printing. DMAS Assessment system has been piloted into seventh grade students at Kimpton Middle School, Stow, Ohio on 10/05/2007 for real-life testing and apparently teacher and student's feedback gave good impression and encouraging feedback about the DMAS system. However, our goal is to put DMAS system under extensive trial in schools and collecting feedback and suggestions from teachers, students, school administrators and education experts to help evolve DMAS. As more schools adopt DMAS, the distributed nature of DMAS will be demonstrated in realistic situations. Because DMAS has been designed in consultation with middle school teachers and education experts, the underline DMAS system design and framework is easy and flexible for future changes, requirements, expansions, and customizations. DMAS provides features to support real-life test giving such as loss of power to a laptop and retaking of tests.
6861036
Practical factorization of univariate polynomials over finite fields
Research presented fort to establish state-of-the-art Kent State University “ Kent, Ohio 44242-0001 here is part of an effactoring routines for polynomials. The foundation of such algorithms lies in the efficient factorization over a finite field GF(p~). The Cantor-Zassenhaus algorithm together with innovative ideas suggested by others is compared with the Berlekamp algorithm. The studies led us to design a hybrid algorithm that combine the strengths of the different approaches. The algorithms are also implemented and machine timings are obtained to measure the performance of these algorithms.
38040297
A Mammography Database and View System for the African American Patients
In this research, we have obtained and scanned mammography films (within the last ten years) of African American women treated at Howard University Hospital Radiology Department, constructed a database using the digitized mammography images, and developed an image viewing system to display these digital mammograms. The images are scanned with the high resolution Kodak LS85 laser scanner. The digital mammography database is powered by MySQL and PHP. It also has a Web-based search engine (with secure access) so that the information can be made accessible to all medical team members. The image viewing software, D-Viewer, is coded in C# and is intended to help medical professionals view and retrieve large data sets in near real time. We have already digitized 260 cases (one case per patient, twenty to forty films per case). We also have developed a MySQL-based image database, and a PHP-based web-search engine to retrieve cases that have masses (benign or malignant) or calcifications (benign or malignant). This database has been evaluated by medical professionals and the experimental results obtained so far are very promising (high image qualities, fast access time). We are currently developing an image content-based retrieval function for the database system in order to provide improved search capability for the medical professionals.
5084706
Pipes: linguistic support for ordered asynchronous invocations
We describe pipes, a new linguistic mechanism for sequences of ordered asynchronous procedure calls in multiprocessor systems. Pipes allow a sequence of remote invocations to be performed in order, but asynchronously with respect to the calling thread. Using pipes results in programs that are easier to understand and debug than those with explicit synchronization between asynchronous invocations. The semantics of pipes make no assumptions about the underlying architecture, which enhances code portability. However, the implementation of pipes by the language compiler can be optimized so as to take advantage of any underlying message ordering a particular architecture may provide. Pipes also provide application-transparent flow control for asynchronous invocations and are able to throttle invocations from multiple calling threads. We present four implementations of pipes and show that the performance and space overheads associated with pipes are low.
167446339
Understanding online archiving
42818567
Scalable Concurrent B-Trees Using Multi-Version Memory
We present a new algorithm for implementing a concurrent B-tree on a multiprocessor. The algorithm replicates B-tree nodes on multiple processors (particularly nodes near the root of the tree) to eliminate bottlenecks caused by contention for a single copy of each node. In contrast to other replication or caching strategies that provide some form of coherence, the algorithm uses a novel replication strategy, calledmulti-version memory. Multi-version memory weakens the semantics of coherent caches by allowing readers to access “old versions” of data. As a result, readers can run in parallel with a writer. Using multi-version memory for the internal nodes of a B-tree reduces the synchronization requirements and delays associated with updating the internal nodes. Experiments comparing the B-tree algorithm based on multi-version memory to other algorithms based on coherent replication show that using multi-version memory enhances throughput significantly, even for small numbers of processors, and also allows throughput to scale with increasing numbers of processors long past the point where other algorithms saturate and start to thrash.
6204027
A non-equilibrium analysis and control framework for active queue management
We present a non-equilibrium analysis and control approach for the Active Queue Management (AQM) problem in communication networks. Using simplified fluid models, we carry out a bifurcation study of the complex dynamic queue behavior to show that non-equilibrium methods are essential for analysis and optimization in the AQM problem. We investigate an ergodic theoretic framework for stochastic modeling of the non-equilibrium behavior in deterministic models and use it to identify parameters of a fluid model from packet level simulations. For computational tractability, we use set-oriented numerical methods to construct finite-dimensional Markov models, including control Markov chains and hidden Markov models. Subsequently, we develop and analyze an example AQM algorithm using a Markov Decision Process (MDP) based control framework. The control scheme developed is optimal with respect to a reward function, defined over the queue size and aggregate flow rate. We implement and simulate our illustrative AQM algorithm in the ns-2 network simulator. The results obtained confirm the theoretical analysis and exhibit promising performance when compared with well-known alternative schemes under persistent non-equilibrium queue behavior.