Virginia Tech - Wake Forest University School of Biomedical Engineering & Sciences
Computer Science Technical Reports @Virginia TechNot a member yet
997 research outputs found
Sort by
Voice Navigation of Structured Web Spaces
Get PDFVoice Navigation of web spaces has become a reality in the last few years, partly due to the rapid adoption of VoiceXML and the increase in communication quality and computing power of cell-phones. This report discusses some of the approaches on how to convert the web content to a way that could be used from a voice-enabled phone. These approaches have different pros and cons when it comes to the usability of the voice-navigation of web spaces. This report discusses our work to produce voice navigation of web spaces placing usability as the highest criteria. We have designed of a voice user interface for pages with a fixed structure and user-specified content, such as My Yahoo! pages. For these types of pages, we have defined the voice navigation strategy that we will use and conducted an initial usability study on this navigation strategy. From the usability study we have obtained validation for some of our approaches, and learned some new concepts in voice navigation as well. With our findings, we are defining annotation tags that can be used to produce highly usable web pages over a phone user interface. In this paper we describe our initial study and the findings of the study
Multidisciplinary Design Optimization with Quasiseparable Subsystems
No full textNumerous hierarchical and nonhierarchical decomposition strategies for the optimization of large scale systems, comprised of interacting subsystems, have been proposed. With a few exceptions, all of these strategies have proven theoretically unsound. This paper focuses on a class of quasiseparable optimization problems narrow enough for a rigorous decomposition theory, yet general enough to encompass many large scale engineering design problems. The subsystems for these problems involve local design variables and global system variables, but no variables from other subsystems. The objective function is a sum of a global system criterion and the subsystems’ criteria. The essential idea is to give each subsystem a budget and global system variable values, and then ask the subsystems to independently maximize their constraint margins. Using these constraint margins, a system optimization then adjusts the values of the system variables and subsystem budgets. The subsystem margin problems are totally independent, always feasible, and could even be done asynchronously in a parallel computing context. An important detail is that the subsystem tasks, in practice, would be to construct response surface approximations to the constraint margin functions, and the system level optimization would use these margin surrogate functions. The purpose of the present paper is to present a decomposition strategy in a general context, provide rigorous theory justifying the decomposition, and give some simple illustrative examples
Open Peer to Peer Technologies
Get PDFPeer-to-peer applications allow us to separate out the concepts of authoring information and publishing that same information. It allows for decentralized application design, something that is both an opportunity and a challenge.
All the peer-to-peer applications, in various ways, return the content, choice, and control to ordinary users. Tiny end points on the Internet, sometimes even without knowing each other, exchange information and form communities. In these applications there are no more clients and servers, instead the communication takes place between cooperating peers.
There are many applications nowadays which are being labeled as peer-to-peer. A way to examine the distinction of whether an application is peer-to-peer or not is to check on the owner of the hardware that the service runs on. Like Napster, if the huge part of the hardware that Napster runs on is owned by the Napster users on millions of desktops then it is peer-to-peer. Peer-to-peer is a way of decentralizing not only features, but costs and administration also. By decentralizing data and therefore redirecting users so they download data directly from other user's computers, Napster reduced the load on its servers to the point where it could cheaply support tens of millions of users. The same principle is used in many commercial peer-to-peer systems. In short peer-to-peer cannot only distribute files. It can also distribute the burden of supporting network connections. The overall bandwidth remains the same as in centralized systems, but bottlenecks are eliminated at central sites and equally importantly, at their ISPs.
Search techniques are important to making peer-to-peer systems useful. But there is a higher level of system design and system use. Topics like trust, accountability and metadata have to be handled before searching is viable
Generation of a User Interface Prototype from an Integrated Scenario Specification
Get PDFThis report discusses the design for the generation of a device independent user interface prototype for services offered by a digital library from an Integrated Scenario Specification using class diagrams and collaboration diagrams as input. The project was conceived as an extension to the SUIP tool, which generates a User interface in java. But this approach has an inherent problem. The interfaces thus generated have the java look and feel and this can't be changed if the user so desires. Our design overcomes this drawback by generating the interface in UIML which is device independent and thus it is
possible to render the code in java, HTML, WML and other languages. The report aims at providing details about the intricacies of the design and deployment. In addition, it also lists possible enhancements to the code that could be taken up as future work
A Web Based Architecture for Visually Coordinating and Publishing Multiple View Visualizations
Get PDFUser coordinated visualizations are a powerful mechanism for building a visual interface. They allow a user to tailor an interface to their needs by choosing components, allowing visual representations customized to a task or user preferences. Snap-Together Visualization (Snap) is a web based system that allows for the creation and sharing of user customized visual interfaces. Users can bring their data to the system, compose a multiple-view interface, and visualize the data. They are then able to share the data and visual interface with other web users by providing a single URL. Snap provides a flexible architecture for coordinating independent interface components and sharing the resulting visualization
Globally Optimal Transmitter Placement for Indoor Wireless Communication Systems
No full textIn this paper, a global optimization technique is applied to solve the optimal transmitter placement problem for indoor wireless systems. An efficient pattern search algorithm ---DIRECT (DIviding RECTangles) of Jones, Perttunen, and Stuckman(1993)---has been connected to a parallel 3D radio propagation ray tracing modeler running on a 200-node Beowulf cluster of Linux workstations. Surrogate functions for a parallel WCDMA (wideband code division multiple access) simulator were used to estimate the system performance for the global optimization algorithm. Power converage and BER(bit error rate) are considered as two different criteria for optimizing locations of a specified number of transmitters across the feasible region of the design space. This paper briefly describes the undrelying radio propagation and WCDMA simulations and focuses on the design issues of the optimization loop
S4W: Globally Optimized Design of Wireless Communication Systems
No full textIn this paper, a global optimization technique is applied to solve the optimal transmitter placement problem for indoor wireless systems. An efficient pattern search algorithm -- DIRECT (DIviding RECTangles) of Jones,Perttunen, and Stuckman(1993)--has been connected to a parallel 3D radio propagation ray tracing modeler running on a 200 node. Beowulf cluster of Linux workstations. Surrogate functions for a parallel WCDMA (wideband code division multiple access) simulator were used to estimate the system performance for the global optimization algorithm. Power coverage and BER (bit error rate) are considered as two different criteria for optimizing locations of a specified number of transmitters across the feasible region of the design space. This paper briefly describes the underlying radio propagation and WCDMA simulations and focuses on the design issues of the optimization loop
Performance of a Parallel Transport Code for Molecular Electronics Simulations
Get PDFWe describe the sequential and parallel performance of a nonlinear transport simulation
code. This code is used by researchers at Virginia Tech to investigate phenomena underlying
the emerging eld of molecular electronics. The computational requirements of the code are
summarized, and an initial distributed-memory parallel implementation of the code is evaluated.
We conclude with several suggestions for improving the parallel performance and scalability of
the code
Overview of Digital Library Components and Developments
Get PDFDigital libraries are being built upon a firm foundation of prior work as the high-end information systems of the future. A component architecture approach is becoming popular, with well established support for key components like the repository, especially through the Open Archives Initiative. We consider digital objects, metadata, harvesting, indexing, searching, browsing, rights management, linking, and powerful interfaces. Flexible interaction will be possible through a variety of architectures, using buses, agents, and other technologies. The field as a whole is undergoing rapid growth, supported by advances in storage, processing, networking, algorithms, and interaction. There are many initiatives and developments, including those supporting education, and these will certainly be of benefit in Latin America
Multifaceted Web Services: An Approach to Secure and Scalable Grid Scheduling
Get PDFA multifaceted or multi-interface web service is a web service that offers interfaces to clients and to other peer web services. The multifaceted web service uses a generic parameter-based approach developed in this paper to allow for collaboration between web servers. This parametric approach solves security and scalability problems and is found to be applicable in many situations. Such an approach is necessary to permit easy collaboration and secure resource sharing. We describe one instantiation of such an approach in the form of a global grid scheduler for data parallel (or Single Program Multiple Data) programs. This scheduler demonstrates the usefulness of our approach in current business environments where administrative policies are a major factor in scheduling decisions