Leonidas Deligiannidis

A software model and specification language for non-WIMP user interfaces

We present a software model and language for describing and programming the fine-grained aspects of interaction in a non-WIMP user interface, such as a virtual environment. Our approach is based on our view that the essence of a non-WIMP dialogue is a set of continuous relationships—most of which are temporary. The model combines a data-flow or constraint-like component for the continuous relationships with an event-based component for discrete interactions, which can enable or diable individual continuous relationships. To demonstrate our approach, we present the PMIW user interface management system for non-WIMP interactions, a set of examples running under it, a visual editor for our user interface description language, and a discussion of our implemantation and our restricted use of constraints for a performance-driven interactive situation. Our goal is to provide a model and language that captures the formal structure of non-WIMP interactions in the way that various previous techniques have captured command-based, textual, and event-based styles and to suggest that using it need and not compromise real-time performance.

Navigating inexpensively and wirelessly

One of the main focuses in immersive virtual environment research is traveling techniques. A traveling technique depends primarily on the tasks needed to be performed as well as the device(s) used to accomplish a given task. In this paper we examine the potential of a relatively new and inexpensive device introduced in the gaming industry that revolutionized the way 3D games are played. We developed two techniques, both utilizing the wireless Wii remote and its extension from Nintendo, and we examined the usefulness of the remote in traveling techniques in large virtual environments. Our technique allows efficient and comfortable control of multiple degrees of freedom using one hand. We performed a user study to measure the effectiveness of the device and we present our results.

Improving Performance of Virtual Reality Applications Through Parallel Processing

DLoVe (Distributed Links over Variables evaluation) is a new model for specifying and implementing virtual reality and other next-generation or “non-WIMP” user interfaces. Our approach matches the parallel and continuous structure of these interfaces by combining a data-flow or constraint-like component with an event-based component for discrete interactions. Moreover, because the underlying constraint graph naturally lends itself to parallel computation, DLoVe provides for the constraint graph to be partitioned and executed in parallel across several machines, for improved performance. With our system, one can write a program designed for a single machine but can execute it in a distributed environment with minor code modifications. The system also supports mechanics for implementing or transforming single user programs into multi-user programs. We present experiments demonstrating how DLoVe improves performance by dramatically increasing the validity of the rendered frames. We also present performance measures to measure statistical skew in the frames, which we believe is more suitable for interactive systems than traditional measures of parallel systems, such as throughput or frame rate, because they fail to capture the freshness of each rendered frame.

Visualizing creative destruction in entrepreneurship education

Creative destruction — the creation of new industries and the destruction of old industries — is a very abstract concept. Those teaching entrepreneurship, where creative destruction is a central feature, often struggle to communicate the dynamism of industry evolution where industry disruption can yield innovation, entrepreneurial opportunities and new wealth. This paper examines the application of human computer interaction (HCI) and specifically information visualization to the context of entrepreneurship education, a specialized area of business education. The chief aim is to evaluate two-dimensional visualizations of industry emergence and growth to compare entrepreneurship learning outcomes in the general comprehension of creative destruction, the specific comprehension of new market creation in industry evolution, and the rates and dynamics of changing industry market structure. Different two-dimensional visualizations of creative destruction in the Popular Music Industry examining 1951–2008 are developed and tested to determine which visualizations correspond to improved entrepreneurship learning outcomes.

DLoVe: using constraints to allow parallel processing in multi-user virtual reality

In this paper, we introduce DLoVe, a new paradigm for designing and implementing distributed and nondistributed virtual reality applications, using one-way constraints. DLoVe allows programs written in its framework to be executed on multiple computers for improved performance. It also allows easy specification and implementation of multi-user interfaces. DLoVe hides all the networking aspects of message passing among the machines in the distributed environment and performs the needed network optimizations. As a result, a user of DLoVe does not need to understand parallel and distributed programming to use the system; he or she needs only be able to use the serial version of the user interface description language. Parallelizing the computation is performed by DLoVe, without modifying the interface description.

Parallel Video Processing Techniques for Surveillance Applications

In this paper we present several solutions to Security Surveillance and their applications while utilizing parallel processing for improved performance. The algorithms presented in this paper are explained in detail and their implementations are provided for free for educational purposes. These algorithms with their implementations are being taught in our Parallel Processing course utilizing NVidias Cuda language and framework. We chose the topic of Security Surveillance in our Parallel Processing course because the results are visual and applicable in many situations such as Surveillance of parking lots (monitoring our car for example), dormitory rooms, offices, etc. Image processing techniques and algorithms are discussed in this paper, and extended to real-time high definition video processing focusing on surveillance.

Visualization of Two Parameters in a Three-Dimensional Environment

Visualization techniques and tools allow a user to make sense of enor mous amount of data. Querying capabilities and direct manipulation techniques ena ble a user to filter out irrelevant data and focus only on information that could yield to a conclusion. Effective visualization techniques should enable a user or an analyst to get to the conclusion in a short time and with minimal training. We illustrate, via three different research projects, how to visualize two parameters where a user can get to a conclusion in a very short amount of time with minimal or no training. The two parameters could be the relation of documents and their importance, or spatial events and their timing, or even the ration between carbon dioxide emission levels and number of trees per country. To accomplish this, we visualize the data in a three dimensional environment on a regular computer display. For data manipulation, we use techniques familiar to novice computer users.

Visualization of Events in a Spatially and Multimedia Enriched Virtual Environment

Semantic Event Tracker (SET) is a highly interactive visualization tool for tracking and associating activities (events) in a spatially and Multimedia Enriched Virtual Environment. SET provides integrated views of information spaces while providing overview and detail to improve perception and evaluation of complex scenarios. We model an event as an object that describes an action and its location, time, and relations to other objects. Real world event information is extracted from Internet sources, then stored and processed using Semantic Web technologies that enable us to discover semantic associations between events. We use RDF graphs to represent semantic metadata and ontologies. SET is capable of visualizing as well as navigating through the event data in all three aspects of space, time and theme.

Sparrow: A Smart Device for Fall Prevention

An interdisciplinary, inter-institutional team of engineers, professors and physicians have demonstrated Sparrow, a simple to use tool to provide nurses the information they need to lower the fall rate among the elderly. Sparrow fuses multiple sensors, a microprocessor, and internet technologies into a wheel chair accessory that communicates with any Android mobile device that has downloaded the Sparrow mobile App. The mobile Android device carried by a caregiver is sent continuous information about a wheelchair occupants position, movement and posture. This information, combined with the experiences and observations of the caregiver, provide medical professionals or family members the opportunity to prevent a fall by returning in a timely manner to help the patient or loved one, who may soon attempt an unobserved and unattended egress from the chair.

Visual and proprioceptive integration of the virtual and real fingertips

Sensitivity to sensory conflicts involving visual and proprioceptive mismatches of fingertip position was explored for a virtual workspace displayed through a stereoscopic head mounted display. The virtual fingertip appeared either coincident with the actual fingertip, or displaced 2, 3, 4, or 5cm in a direction parallel to either the sagittal or frontal planes. Observers did not reliably detect displacements smaller than 5cm. Sensitivity to 5cm displacements varied across the workspace, as a function of the direction of the displacement, and between the right and left hands. Implications for proprioceptive localization of the hand are discussed, as well implications for performance in virtual environments.