OBJECTIVE: The integrated Translational Health Research Institute of Virginia (iTHRIV) aims to develop an information architecture to support data workflows throughout the research lifecycle for cross-state teams of translational researchers. MATERIALS AND METHODS: The iTHRIV Commons is a cross-state harmonized infrastructure supporting resource discovery, targeted consultations, and research data workflows. As the front end to the iTHRIV Commons, the iTHRIV Research Concierge Portal supports federated login, personalized views, and secure interactions with objects in the ITHRIV Commons federation. The canonical use-case for the iTHRIV Commons involves an authenticated user connected to their respective high-security institutional network, accessing the iTHRIV Research Concierge Portal web application on their browser, and interfacing with multi-component iTHRIV Commons Landing Services installed behind the firewall at each participating institution. RESULTS: The iTHRIV Commons provides a technical framework, including both hardware and software resources located in the cloud and across partner institutions, that establishes standard representation of research objects, and applies local data governance rules to enable access to resources from a variety of stakeholders, both contributing and consuming. DISCUSSION: The launch of the Commons API service at partner sites and the addition of a public view of nonrestricted objects will remove barriers to data access for cross-state research teams while supporting compliance and the secure use of data. CONCLUSIONS: The secure architecture, distributed APIs, and harmonized metadata of the iTHRIV Commons provide a methodology for compliant information and data sharing that can advance research productivity at Hub sites across the CTSA network.

Numerous Grid workflow engines exist, each generally specialized for a single application domain such as protein folding. Although the underlying purpose and functionality of the Grid workflow engines are similar, and they make use of a common set of Grid protocols, the implementations vary vastly, making interoperation among them nearly impossible. On the other hand, the concept of workflows of Web services is very popular in the enterprise domain and many engines exist for business workflows. These mostly revolve around the Business Process Execution Language (BPEL), an emerging standard for Web services workflow description. We study three different business workflow engines - Microsoft's BizTalk Server, Microsoft's Windows Workflow Foundation and Oracle's Business Process Manager and analyze how each of these engines can be adapted to e-science and the Grid environment. We have implemented widely-used grid workflows on each of these engines and show quantitatively and qualitatively that each business engine has positive and negative aspects for large-scale e-science.

E-Science often requires access to remote Grid computing platforms. Current authorization systems on these remote systems have largely based decisions solely on the identity of the submitter -- the job is permitted to execute on the local resource if the job originates from an authenticated and authorized end-user. The problem with this approach is that there is no consideration to what the job will/should do when executed, so an errorful or malicious job -- even from what purports to be a trusted user -- can create significant damage before an operator notices and can kill or suspend the job. This paper presents a novel end-to-end job execution framework in which the properties (behavior) of the job are taken into account for the authorization decision. Experimental results show the duration to perform the authorization and to establish a subsequent restrictive execution context is sufficiently low -- our observed overhead of 253.1 ms on commodity hardware is an acceptable cost for most Grid applications to pay to achieve this more secure execution environment.

Grid computing involves networks of heterogeneous resources working in collaboration to solve problems that cannot be addressed by the resources of any one organization. A pervasive problem for grid users is how best to discover the resources they need given dynamic grid environments. UDDI, the universal description, discovery and integration framework, is an OASIS standard for publishing and querying discovery information for Web services, which to date, has received surprisingly little analysis as a discovery mechanism for Web service-based grids, e.g. those based on the open grid services architecture (OGSA). This work identifies issues that must be addressed in order to make UDDI meet the requirements of OGSA discovery. We examine the performance implications of these issues using a freely available implementation of UDDI version 2. Based on our experimental results, we conclude that UDDI can be used for OGSA discovery, but the cost may be prohibitive for large grids.

The Web services resource framework defines conventions for managing state in distributed systems based on Web services, and WS-notification defines topic-based publish/subscribe mechanisms. We analyze five independent and quite different implementations of these specifications from the perspectives of architecture, functionality, standards compliance, performance, and interoperability. We identify both commonalities among the different systems (e.g., similar dispatching and SOAP processing mechanisms) and differences (e.g., security, programming models, and performance). Our results provide insights into effective implementation approaches. Our results may also provide application developers, system architects, and deployers with guidance in identifying the right implementation for their requirements and in determining how best to use that implementation and what to expect with regard to performance and interoperability.

This paper presents a characterization study of the HOKUYO PBS-03JN Infrared range-finder and compares it to the characterization of the SICK LMS-200 laser range-finder for use in indoor 2-D mapping. Many parameters that could affect the performance of the sensor including warm-up time, divergence of the detection beam, usable detection range in the azimuth, target surface, color, and size properties, incidence angle at the target, and the mixed pixels problem have been studied. This characterization, quantification of errors, and 3-D confidence in the distance readings of the sensor is vital for practical applications. These characteristics are compared to the counterpart characteristics of the laser range-finder. The PBS-03JN is a cost effective alternative to laser range-finders in indoor environments. The sensor is attractive due to lower power consumption, and its lightweight.

The Open Grid Services Architecture (OGSA) has been a major step forward for Grid Computing, but its de facto reliance on the Web Services Resource Framework (WSRF) and WS-Notification have left some in the community questioning if the Grid software and protocols have become too complex. In this paper, we consider the feasibility of an "alternative" software stack, based on WS-Transfer and WS-Eventing. We compare and evaluate WSRF/WS-Notification vs. WS-Transfer/WSEventing, first via a "hello world" service and then via a more complete Grid scenario for remote execution called "Grid-in-a-Box". By qualitatively and quantitatively evaluating each approach, we find that while subtle differences exist (e.g., the naming of resources, the creation of resources), the stacks are overwhelmingly equivalent in their functionality and implied performance. Overall, this paper uniquely shows that there could be alternative software stacks for OGSA-based Grids.

The Open Grid Service Infrastructure (OGSI) has been designed to facilitate the creation of multiple, interoperable Grid service hosting environments, but to date only one fully OGSI-compliant hosting environment exists, Globus Toolkit version 3 (GT3). This paper describes the design and implementation of OGSI.NET, which is the second, independent hosting environment that is fully compliant with the OGSI specification. While the Microsoft suite of Visual Studio, Internet Information Services (IIS), and the Web Services Enhancements (WSE) provide a robust foundation upon which we implemented OGSI.NET, the challenges included constructing the Grid service container, parsing OGSI WSDL ("gwsdl"), and supporting Grid service handles (GSH). By describing our approach to these challenges, and by describing the unique Grid attribute programming. model we are developing as part of OGSI.NET, we contribute an early evaluation of OGSI and the broader Open Grid Services Architecture (OGSA).

This paper presents a physics-based model approach to infer navigational intent of the user of a walker, based on measuring forces and moments applied to the walker's handles. Our experiments use two 6-DOF force/moment sensors on the walker's handles, a 2-D kinematic-dynamic model of the walker and a digital motion capture system to trace the path of the walker. The motion capture system records the path the walker follows while the 6 DOF sensors record the handle forces used to guide the walker along that path. A dynamic model of the walker that determines user navigational intent from force/moment data was developed and validated against the motion capture data streams. This paper describes the development and validation of the model as well as plans for using the model as a path predictor. The inferred user intent is incorporated into a passive shared steering control system for the walker.

This paper presents a novel approach to infer navigational intent of the user of a walker, based on measuring forces and moments applied to the walker's handles. While there are many types of "intent" that could be inferred for a given user action, the experiments conducted here focused on the determining user's navigational intent, i.e. their desired heading. Our experiments used two 6-DOF force/moment sensors on the walker's handles and a digital motion capture system to correlate applied force with actual motion. Preliminary results revealed that the intent to turn, represented by changes in the heading angle, highly correlates with the overall turning moment around the vertical axis as well as the side forces applied by the user. Other force/moment components reveal additional information, such as support needs. The inferred user intent will be incorporated into a passive shared steering control system for the walker.

Globus is a powerful toolkit but lacks location transparency in its naming system, due to a reliance on URLs. In practical terms, this means that a Grid user (or software running on behalf of the user) must know precisely where Grid entities are. The problem is that hardware reconfiguration, file system reorganization, and changes in organizational structure can often result in dangling links. At the University of Virginia, we are designing and implementing a comprehensive project that combines the best aspects of Globus and Legion into Legion-G - roughly an "applications-level" interface from Legion to Globus, whereby Legion "runs on" key Grid functionality of Globus such as GSI. Among the capabilities already supported in Legion, and thus will be delivered to the Globus user, are: end-user tools for transparent remote execution and parameter-space studies; support for dynamic, transparent remote instantiation of transient Grid services, with integrated scheduling support; fine-grained access control for Grid services; and the Legion programming model which supports arbitrary, asynchronous, data-flow-style, secure Grid computations. This poster describes the Legion-G support for location-transparent naming in Grid Computing and illustrates its value in the context of Globus MPI computations that accesses LegionFS which is a location-transparent, Grid-enabled distributed file system.