Showing papers presented at "Virtual Environments, Human-Computer Interfaces and Measurement Systems in 2007"

Handbook for Evaluation Studies in Virtual Reality

Abstract: Virtual reality (VR) applications are spreading and attract industries since VR technologies are becoming more affordable, powerful and robust. VR applications inherently call for human-computer interaction, which in turn calls for system and usability evaluations, typically through measurement of human behavior including aspects of perception, action, and task-performance. The evaluation issue calls for multi- and interdisciplinary research activities, where technical expertise is combined with humanistic knowledge and methodology. Several experts in the field of VR as well as in the field of usability studies call for helpful guidelines in order to be able to evaluate VR applications. This paper gives an overview of this problem and introduces a guideline which is supposed to assist researchers in evaluating VR applications. In particular, it aims at assisting those who are not experts in evaluation studies as well as students. The aim is also to facilitate multi-disciplinary activities through the use of an evaluation handbook which would be simple and focused on VR. The applicability of this guideline has been tested in two pilot studies, which showed how this handbook could successfully be employed to carry out pilot (and formal) evaluations.

A Projection-based User Interface for Industrial Robots

Abstract: This paper presents a novel spatial user interface system for industrial robots, which relies on interactive projection in conjunction with a handheld stylus as the central medium for user-interaction. This way, complex spatial trajectories and other information can be edited directly in the workspace of the robot. Calibration mechanisms, interaction metaphors and methods for multi-projector-setups will be discussed. The system relies on an active optical tracking system, with a dedicated handheld probe that is suitable for robot teaching and the implied handling in six degrees-of-freedom. Both, laser projectors and video beamers have been incorporated into the system and will be evaluated for their specific properties in the context of a spatial user interface. Interaction mechanisms and metaphors include e. g. free editing, drag-and-drop for 3D-trajectories on workpiece surfaces, virtual menus projected into the workspace and interactive modeling of collision geometries and workpiece shapes.

Constructing 3D Virtual Reality Objects from 2D Images of Real Objects Using NURBS

Abstract: A new method for capturing and reconstructing 3D representations of real objects in a virtual reality system is introduced. Virtual reality applications allow users to navigate and interact with the 3D objects through the environment. This interaction requires that the 3D representation of real objects be highly accurate in modeling the reality. The novelty of the new methodology proposed, consists on the fact that it uses only a high resolution (7 megapixels or higher) digital camera and a projector in conjunction with 3D surface reconstruction techniques based on non-uniform rational Bzier spline (NURBS) functions. The 3D object reconstruction is based on finding unique control points on the 2D images of the object and constructing corresponding 2-D NURBS curves which contain the control points through a process of NURNS fitting. The control points are situated on grid lines which are extracted from the object surface on which a color coded grid is projected. The 2-D NURBS curves are projected into a 3-D space to eventually re-create the 3-D surface of interest. The method does not require any a priori knowledge of the absolute positioning or orientation of the camera and the projector as other 3D reconstruction techniques do. The precision of the method depends on the camera resolution and can attain easily sub-millimeters ranges. Examples illustrate the process.

Towards an Architecture for the Compression of Haptic Media

Abstract: In this paper, we present I-CHAM, an architecture for the intelligent compression of haptic media. The I-CHAM architecture enables both, lossy and lossless compression modes and it encompasses several modules that, together, attempt to intelligently and efficiently compress a haptic media file. Furthermore, the proposed architecture is designed in such a manner to be haptic-application and device independent. To the best of our knowledge, this paper is the first in the literature to propose an architecture for the compression of haptic media files. The experimental results demonstrate that I-CHAM can achieve great compression ratios in both, lossless and lossy modes, while preserving the immersiveness of the haptic-based environment.

A Device Independent Haptic Player

Abstract: This paper presents the design, implementation, and quantitative evaluation of a haptic player system that is independent from the haptic device, in the context of our HAML-based authoring tool project at the University of Ottawa. The system comprises three components: a haptic recorder, a feature extractor, and the haptic player. The haptic recorder is capable of retrieving, filtering, and storing the data sent by a haptic device in a local database. The feature extractor generates a standardized description of the stored data by utilizing the HAML schema. Finally, the haptic player component recreates a haptic stimulus by utilizing the HAML description of the corresponding stimulus. Haptic stimuli are played back according to the haptic device's features. The experimental evaluation of the proposed HAML-based player showed that the haptic player system is independent from the device used during data recording.

Influence of Wi-Fi computer interfaces on RF measurement systems

Abstract: Nowadays wireless low-power technologies, such as Wi-FiTM, ZigBeeTM, BlueToothTM, to cite a few, are often present in measurement environment. Even though designed and developed to reduce at minimum their emissions, however these wireless devices can potentially interfere with metrological performance of modern instrumentation. For these reasons, a careful investigation on the electromagnetic susceptibility of measurement systems, when subjected to interferences generated by short-range low-power wireless transmitters, is carried out. The effects of a Wi-FiTM bridge operating close to a typical radio frequency measurement station are analyzed. The achieved results prove that the effects of the interferences due to the wireless module are not always negligible, thus potentially compromising its performance and the measurement results reliability.

A Collision Detection Algorithm for Point-Like Haptic Interactions in Highly Detailed Virtual Environments

Abstract: In this paper, we present a collision detection algorithm for use in hapto-visual virtual environments containing highly- detailed, rigid, and dynamic models that are manipulated with probe-like haptic devices. Our approach is primarily motivated by the observation that highly detailed virtual models are typically represented by dense point clouds (specifically those that result from high-resolution laser-scans of real-life objects). By not viewing models as the sum of their constituent points, but rather dealing with the vertices individually, we present a novel collision detection algorithm that bounds each individual vertex with an axes-aligned bounding box that is arranged in a modified octree during a preprocessing phase. Collision detection at run-time is then performed via an involved query of the octree searching for the haptic probe's coordinates inside one of the aforementioned bounding boxes. Our algorithm runs in logarithmic time 0(log n) where n is the number of vertices that makes up the model(s). Our approach accommodates environments where objects undergo rotation and translation but on the condition that models remain rigid

Building Learning Communities in Blended Classrooms Through an Innovative mLearning System

Abstract: Chinese classrooms have long suffered from a lack of interactivity Many online classes simply provide recorded instructor lectures for students to listen to This format only reinforces the negative effects of passive non-participatory learning At a major university in Shanghai, researchers and developers actively seek technologic interventions that can greatly increase interactivity in online classes They developed a cutting-edge mobile learning system that can deliver live broadcast of real-time classroom teaching to online students with mobile devices This system allows students to customize means of content-reception The system also supports short text-messaging and instant polls Through these venues, students can ask questions and make suggestions in real time, and the instructor can address them immediately This paper describes this system in detail, and also reports results from a test implementation of the system with a blended classroom of 1000 students (250 campus and 750 online)

A Virtual Assistant for Safety Measurements Evaluating the Worker Hand-Arm Exposure to Percussion Machines Vibration

Abstract: This paper proposes an innovative virtual assistant able to check the safety requirements concerning vibration exposure of workers using hand-held percussion machines. Typically, the exposition to high and continual vibrations with the passing of time may facilitate the onset of pathologies affecting vascular and neurological systems, or be cause of syndromes to hand-arm bones and muscles. So Standards and regulations impose exposure limits in order to prevent health hazards. The projected system is able to measure and estimate the daily worker exposure to vibration according to the Standard ISO 5349. User identification is performed by a personal memory device storing data and information concerning the worker and his daily activity. Three orthogonal transducers measure the acceleration transmitted to the hand-arm system and a DSP unit has the task to process data in order to estimate the vibration exposure during the working activity. If the law safety limits are overcome, the device shows on display an alert message followed by an acoustic alarm so to force the worker to stop the machine usage. The aim of the proposed system is to provide a prevention tool for assuring safe working conditions. The system assists the worker exposed to vibrations in order to avoid the absorption of levels above the maximum tolerable or permitted daily limit.

HI 3 Project: Design and Implementation of the Lower Level Layers

Abstract: We are interested in the development of human-centered and ubiquitous technologies in social environments. In this line, and in the framework of a global software architecture (HI3) for this type of applications, the paper is devoted to the presentation of the work carried out for the design and implementation of the layer that is more closely linked to the hardware. It is in charge of communicating with the physical layer and it is responsible for the abstraction of the field elements. Special attention has been paid to the coherence with the philosophy, design premises and functionalities of the whole system. We have also determined a hardware configuration that, integrating standards where possible, is better adapted to the requirements of the architecture. The elements introduced here were validated on a real implementation of the system.

A Force Feedback Virtual Simulator for Education and Training

Abstract: The essential requirements of a virtual reality based simulator are a realistic virtual environment and a reproduction of haptic sensation due to the interactions in the virtual environment. The interactions need to be performed in real-time, since a delay between the user action and the system reaction reduces the user experience. Accuracy and efficiency are two opposite requirements; in fact, increased accuracy implies higher computational time and vice versa. So, it is necessary to find a trade-off according to the application and, sometimes, to reduce the realism in favour of the real-time interaction. In this paper is presented a virtual simulator provided of a haptic interface and a virtual environment reconstructed from real patient's medical images in order to have haptic sensations in addition to a very realist virtual environment.

Expressions of Emotions in Virtual Agents: Empirical Evaluation

Abstract: Human communication is mainly based on speech, gestures, facial and bodily expressions. Nonverbal expressions, as body posture and small movements, regulate social interactions. These results lead to an ever-growing effort from behalf of researchers in the human-computer interaction field to include emotions and emotional expressivity in their projects. Evaluation of emotion expressions recognition becomes, thus, an important step in the development of project involving interaction between humans and avatars. In the present paper we describe the results of an evaluation experiment made in two settings: discrimination between three videos looking for a specific emotion expression and identification task that asks for the selection of a list of a seen expression. The obtained results are similar to previous studies from the field and underline again the necessity of careful design of some particular emotions, especially those one that can be considered from the same family.

A New Graphical Interface For Web Search Engine

Abstract: Aim of this work is to present a new human computer interface for Web search engines. Despite the noteworthy improvements introduced in the Web search engines, their human interface still remain surprisingly based on a textual sorted list. The position of a site in this list expresses its distance from the user's query. The authors propose a graphical user interface for search engines based on the geomorphologic metaphor. This interface makes user aware of the semantic distribution of the Web sites retrieved by the search engine. The proposed interface is implemented as a browser plug-in and it is able to work with all the modern search engines.

A New Approach For Handling 3D Medical Data In An Immersive Environment

Abstract: Medical Imaging applications use images coming from different sources such as magnetic resonance imaging (MRI), computer tomography (CT), positron emission tomography (PET), to generate 3D data Starting from these volumetric data, applications reconstruct 3D models of anatomical structures which could be manipulated and analyzed In this paper we present a new approach for the visualization and interaction with volumetric datasets in a fully immersive environment It allows to handle the reconstructed models directly within the virtual scene; in particular a technique is described for outlining the Volume Of Interest (VOI) functionality in a three-dimensional dataset for a visual interactive inspection and manipulation of the organ of interest

Java-Based Adaptable Middleware Platform for Virtual Instrumentation

Abstract: The increasing heterogeneity of instruments, devices, and measurement systems with varying operating systems, processors, hardware devices, resources, etc. interconnected by different networks require the design and development of new middleware platforms, capable of managing the complexity of current distributed systems. In this work the design and development of a new adaptable middleware platform is proposed based on the study of the state-of-the-art distributed systems technology and the development of novel mechanisms and services on top of known middleware architectures. The new platform will allow for easier instrument and data integration. This paper outlines the steps involved in the development of the proposed Jini-based middleware, JOVIM, establishing the requirements for such a platform and describing its main characteristics and mechanisms.

The Study of Image Definition Evaluation Function Based on Wavelet Filter

Abstract: The auto-focus method based on digital image processing results from the innovation of the traditional auto-focus method. Generally speaking, the traditional auto-focus method needs extra focus equipment and can be disturbed easily by environment factors. So the application of the traditional auto- focus method is limited hugely. The auto-focus method based on digital image processing is usually achieved by image definition evaluation functions. The paper studies the structure of two-dimension minimum isotropy wavelet filters and propounds the image definition evaluation based on a wavelet filter. In the paper, the evaluation function based on the wavelet filter is compared with the evaluation function based on the Laplacian operator by using the auto-focus system of a microscope. The experiment results indicate that the auto-focus algorithm based on the isotropy wavelet filter has good performance.

Distributed Database for Environmental Data Integration

Abstract: An information system supporting environmental applications must be reliable, scalable and able to acquire and integrate data from a lot of monitoring stations distributed in different places. This paper proposes a system integrating the data acquired by a distributed network of sensors for air quality monitoring. The monitoring system is based on a well-tested Multi Agent System architecture based on functions layering. Aim of this paper is to highlight the behavior of the MAS while it is integrating data from multiple information sources and present an innovative method for Web based information source integration.

Supporting Large-Scale Networked Virtual Environments

Abstract: In this paper, we introduce a framework that supports a large number of participants in a collaborative virtual environment (CVE). We consider object classification based on avatars' physical characteristics to define the overlay network used to disseminate update messages between participants. This concept systematically puts objects into different logical clusters where each cluster can be rated in terms of a persistency class. We integrate a greedy heuristic algorithm to form a better network structure and then apply the dominating set principle to build a routing table for intra-zone communication. In this paper, we have used OPNET to verify the applicability of these approaches to large-scale CVEs.

A distributed measurement system based on Peer-To-Peer architecture for River Monitoring

Abstract: Several applications require for a distributed measurement system able to measure the same or different parameters at different points in a wide area. Distributed systems based on smart Web sensors represent the best solution to many different measurement problems. One of the main disadvantages of monitoring systems based on smart Web sensors is the difficulty to have a complete access to all data because they present a closed approach to interact with them, while Web services are adopted in order to give a standard approach in developing a service oriented architecture. The main goal of this paper is to present an implementation of a environmental sensor for distributed measurement system based on the Web service approach, adopting a freeware widely utilized technology, the Gnutella network, to route and share information adopting a low-cost hardware architecture. This solution offers great possibility in terms of fast and easy access to measured data, of integration of large complex Web sensor network, of realization of flexible custom applications and of service reusability developing new measurement application starting with different information also coming from different sensors.

Using the Interleaved Sampling of the Multi-Channels to Broaden Bandwidth of Embedded Oscilloscope Systems

Abstract: In this paper, we propose the design and implementation of an embedded oscilloscope system by using the interleaved sampling of multi-channels to broaden the bandwidth. Each channel has an analog-to-digital converter (ADC), data-buffers and I/O interface. We use multi-channel modules to carry out interleaved sampling for obtaining multiple waveforms sampling during an interval. In the design example we used four sets of ADCs, data-buffers and three I/O interface ICs to construct an interleaved sampling by four-channels. We use a fraction of a clock period as the delay time of each channel, and through merging the four sets of sampling waveform data arrive at the measured waveform. Theoretically, the interleaved sampling of four-channel merging should be able to broaden the bandwidth of an embedded oscilloscope system by 400%. If the bandwidth of an oscilloscope is higher, the price is also higher. The cost of an oscilloscope is in proportion to the bandwidth by an exponential relation, not by a linear one. If we use an interleaved sampling design to increase the bandwidth by 100%, we only need to add a set of ADC and data-buffers besides the cost of the basic embedded system. The cost of an oscilloscope can increase at less than an exponential relation with respect to the bandwidth.

Grid Services for SST Measures

Abstract: The effects of the increase in the average temperature of the Earth's near-surface air and oceans in recent decades are dramatically manifest: desertification, glacier retreat, increased intensity and frequency of hurricanes and extreme weather events. Monitoring the ecosystem is currently the only way we have to assist Governments in making sound decisions concerning the reduction of these dramatic effects and the protection of our environment. Satellite remote sensing data, offering the possibility of covering large spatial area with a high temporal frequency, represents the ideal solution to monitoring, but the huge data volume to process, calibrate and validate by in-situ dataset, cannot be operated effectively by traditional database and computational resources. Grid technology, easily providing powerful computational resources and efficient distributed data management, is an excellent solution for remote sensed data processing and management system. In this paper we present a prototype of a remote sensed data processing system on Grid technology that allows, by a graphical interface, data selection and processing to validate SST measure particularly in costal area.

GIS-based System for Landslide Early Warning Index Measurement

Abstract: Landslides are one of the most serious natural and man induced hazards. The paper presents an innovative system dedicated to the measurement of landslide warning index. The system is based on a geographic information system (GIS) inference engine which properly combine satellite Earth observation (EO) measurements and static geophysical parameters. The system has been developed in the framework of an FP5 European project and it is aimed to provide an operative and flexible tool for public and private entities involved in land management, and in particular in mitigation of both landslide hazard and risk. Particular attention will be devoted to the role that the GIS environment plays as optimal measurement environment since it provides flexible interface between human (both high level geophysical experts and low level end users) and data (heterogeneous data in input to the geophysical model, warning maps in output).

Topology Control Modeling and Measurement for Networked Virtual Environments

Abstract: In this paper we will propose a novel distributed architecture for overlay tree construction in collaborative virtual environments that is unlimitedly scalable due to its fully decentralized nature. The routing issue over this architecture will later be discussed and several forwarding schemes based on distributed hash tables (DHT) will be proposed. One of the main concerns for a routing algorithm is to keep a trade-off between the algorithm locality and the algorithm performance. In a global algorithm where nodes make the forwarding decision based on the information gathered from all other nodes in the network, the routing performance may obviously be better. However such a large group of neighbors result in a large topology discovery cost and huge routing tables when the number of nodes exceeds a certain limit. In this article we will try to find the best trade-off among these factors therefore proposing an optimum neighborhood radius for each node. Finally a comparison will be made regarding path delay criteria among several proposed forwarding schemes at the optimum neighborhood radius point.

Development of A Quality Computation System for Color Filter Inspections

Abstract: The object of this research is to develop a fully automatic computation algorithm for quality control purposes during inspecting color filters. The hardware setup can analyze dyed pixels on the color filters upon acquiring the transmiting-through light waves ranging from 350 nm to 850 nm and a light wavelength resolution up to 3.49 nm, once a micro-spectrometer is employed. With the acquitted information this research builds a quality inspection algorithm to analyze the color properties of the dyed pixels, and performs dedicated statistics computations of the color filters automatically. With the analysis results of the typical color filter, its color quality can be justified using the developed quality computation algorithm, and any defects of the pixels on a sampled filter can also be detected. Hence, the automatic inspection system can evaluate the statistics of the acquired information and identify the grade of the inspected ones in order to assure the quality of each fabricated color filer. .

A Haptic Data Repository Framework

Abstract: The concept of a data repository is not a new idea; almost any scientific approach to a statistical-based problem requires a data storage effort for the purpose of post-processing and post-examination of acquired data sets. When faced with haptic-data, however, we run into several problematic issues, such as high bandwidth requirements (sampling rates equal to or higher than 600 Hz), data accuracy and relevance, data filtration and presentation. In this paper, we propose a haptic-data repository proof-of-concept capable of retrieving, filtering, and storing the compacted data sets in a local database. We introduce an Intelligent Filtering Algorithm, a Thread Management Algorithm, as well as an I/O optimization algorithm. By combining these algorithms, and as our performance evaluation demonstrates, we have successfully been able to save accurate haptic data at sampling rates equals to or higher than 1 KHz.

Constant bit rate Video Coding based on SVD video decomposition

Abstract: In this paper, a novel video coding technique is presented, based on the decomposition of the sequence spanned hyperspace in orthogonal components. Good quality video can be reconstructed at the receiver, particularly for very low bit rate applications, with low residual error and smooth appearance both in motion reconstruction and in the complete absence of crisp coding artifacts such as blocking structures, basing on a few proper selected examples of the speaker and a multidimensional interpolation algorithm. Principal component analysis exploited by singular value decomposition has been used to decompose the video sequence into eigen-images. A limited set of eigen-images is chosen to span the whole video sequence subspace. Only coefficients to be used in the interpolation procedure are transmitted along the communication channel. Preliminary results are presented for Akyio QCIF video sequence.

Development of a System for Soil Microclimatic Analysis

Abstract: In this paper the design and the development of a moisture sensor for granular and porous mediums are presented. In the proposed method the moisture is measured by estimating the velocity of propagation of seismic waves (both compressional and shear ones) between a transmitter and a receiver separated by a known distance. The first experimental results are illustrated and compared with theoretical results.

A RF Identification System for the Improvement of Metrological Activities

Abstract: In this work the authors describe the realization of a "radio-frequency identification system" for the improvement of the metrological activities of a measuring laboratory. Some radio- frequency modules, called by the authors RF smart points ("radio-frequency smart points"), have been designed to store into their memories all data which are necessary for the instruments tracking (the type of instruments, their identification numbers or serial numbers, the manufacturer, the date when they have been admitted to the installed base of the laboratory, their working state, the elapsed time from the last calibration procedure). The insertion of the data and the inquiry of the instruments are executed by the technical staff of the laboratory through a PDA (personal digital assistant) or a PC, which manage the radio-frequency communication by using the RS 232 interface for sending messages to a RF transceiver. The executable software for managing the communication between the smart points and the "PDA/PC-controllers" is realized in LabVIEW graphical programming environment.

L-VCONF: A Location-Aware Infrastructure for Battlefield Videoconferences

Abstract: Audio and videoconference technologies make complex coordination processes easier, especially when mobile participants need to synchronize their action in critical environments. The need for an infrastructure providing such a functionality may arise in complex scenarios where an IP network is not available, as for instance in battlefield or other critical environments. This paper describes L-VCONF, an architecture for geo-located conferencing based on a mobile/cellular network (i.e. GPRS, UMTS, WiMax technologies), quick-and-dirty mobile/cellular geolocation, SIP protocol and presence server. Our architecture supports IP audio/videoconferences enriched with geo-located coordination functionalities in complex environments. The approach described in the paper is robust w.r.t. uncertainty while handling location update notification for SIP presence server.

System Architecture for Personalized User Defined Web Information Retrieval on Demand using PDA or GSM Devices

Abstract: As GSM devices are widely spread around the world. They are today used for many different purposes. This paper presents a new approach in using PDA or GSM devices to establish a system architecture for personalized retrieval of user defined Web information. The solution does not need any special or proprietary hardware devices other than GSM or PDA device with short message service (SMS) capability and PC computer with Internet connection acting as a server.