Showing papers presented at "Virtual Environments, Human-Computer Interfaces and Measurement Systems in 2003"

3D binaural sound reproduction using a virtual ambisonic approach

Abstract: Convincing binaural sound reproduction via headphones requires filtering the virtual sound source signals with head related transfer functions (HRTFs). Furthermore, humans are able to improve their localization capabilities by small unconscious head movements. Therefore it is important to incorporate head-tracking. This yields the problem of high-quality, time-varying interpolation between different HRTFs. A further improvement of human localization accuracy can be done by considering room simulation yielding a huge amount of virtual sound sources. To increase the computational efficiency of the proposed system, a virtual ambisonic approach is used, that result in a bank of time-invariant HRTF filter independent of the number of sources to encode.

Measuring the human side of virtual reality

Abstract: The quality of experience (QoE) of any virtual environment is important to its users; if its QoE is too low, users will cease using the VE. Measuring QoE requires measuring users' responses to the VE. There are three main methods for assessing humans in a VE: subjective, performance, and physiological. Each method lets the researcher collect different types of information: user attitude towards a VE, whether the user can complete a task, and whether a VE poses a health danger towards the user. While many virtual researchers also measure telepresence, there is some controversy to its real correlation with QoE.

Modelling e-commerce systems' quality with belief networks

Abstract: This paper focuses on quality aspects of e-commerce systems and proposes a method for modeling such systems based on belief networks. The paper discusses the theoretical background of the proposed model, as well as practical issues arising from its application. The basic notation and concept of belief networks is briefly presented, while emphasis is placed on the model's structure and its usage. The presented model can be utilized for assessing the quality of e-commerce systems, as well as for aiding in quality assurance during the design and development phase of such systems.

The optimal arrangement of four laser tracking interferometers in 3D coordinate measuring system based on multi-lateration

Abstract: The measuring accuracy of four-beam laser tracking system for 3D coordinate measurement in large degree depends on the arrangement of the interferometers. In this paper the optimal arrangement of four laser tracking interferometers is proposed. The optimal arrangement for measurement is obtained through minimizing the position dilution of position (PDOP) of the measured point. Not only the process of measurement but also the process of self-calibration are influenced by the system arrangement. The relationship between the accuracy of self-calibration and system arrangement is also discussed through computer simulations and experiments. The results show that the nominal arrangement defined in this paper can be considered as the optimal arrangement for 3D coordinate measuring systems based on multi-lateration.

A fuzzy feature clustering with relevance feedback approach to content-based image retrieval

Abstract: The increasing number of digitized images required an efficient image retrieval system. In this paper, we demonstrate the fundamental principles, implementation methods, performance evaluations, and experimental results from the proposed model. We present a region-based prototype image retrieval system named FuzzyImage. The system is characterized by feature vectors. First, we segment an image into regions depending on clustering similar feature vectors by fuzzy c-means. Next, a similar measurement is used to evaluate the similarity between the query image and incorporated regions. The users can select the most interesting regions from 5 sample images that pop-up, and by feedback to the system. Based on the selected individual regions of query images, the overall similarity helps filter out irrelevant images in a database after relevance feedback and enables a simple user-oriented query interface for a region-based image retrieval system. This algorithm is implemented and tested on general-purpose images. This project makes three main contributions to a region-based CBIR system. First, a region segmentation method is employed in the FuzzyImage system. Second, this system takes the user's intuition into consideration and designs a user-oriented interface to directly search the database. Thirdly, we evaluate retrieval precision of the system to support this theoretical claim.

Intelligent, low-power and low-cost measurement system for energy consumption

Abstract: In the area of utility measurement systems, there is increasing awareness to the importance of using intelligent and secure meter readers. The aim is not simply that reducing operational costs; aspects such as availability of real-time determination of consumption (mainly in the case of energy meters, but potentially also for water consumption, etc.) are relevant not only for actions such as real-time billing but also in view of an increasing environmental awareness leading to "preferential" billing in particular times of the day or of the week and requiring availability of fine-grained statistics. All these actions in turn involve the requirement of data integrity; when utilities other than power providers are considered, the device should be battery-powered (and very long battery life must be granted), so that low-power design becomes a further requirement while being permanently either in active or in standby mode; moreover, not being connected to the power network means that wireless connections for transmitting and receiving information must be taken into account. Finally, these deices should be made available to the general public and thus be low-cost ones. This paper describes how all the above constraints have been analyzed in the design of a wireless meter reading system.

Fuzzy sensor for gesture recognition based on motion and shape recognition of hand

Abstract: Gesture recognition needs to take into account very different information. It needs to perform the fusion of hand shape and motion information. This paper presents a solution using a fuzzy sensor approach for the aggregation of such measurement information. Motion recognition is based on a measurement represented by numerical fuzzy subsets, and shape recognition is based on measurements represented by lexical fuzzy subsets.

Script language for avatar animation in 3D virtual environments

Abstract: This paper continues previous work by the authors on the animation of anthropomorphic avatars in virtual reality environments. An avatar animation control system was built in three hierarchical levels: joint control, basic behaviors and script language. This paper focuses on the grammar and parser for the script language, which was designed to be easy to extend and modify. Also, in order to verify how flexible the hierarchical approach is, the two lower control levels were implemented in two different ways, without affecting the script language level.

Performance comparison of different techniques for available bandwidth measurement in packet switched network

Abstract: As variety of applications and services that can be provided on packet switched networks has strongly increased over the last years and keeps on increasing, the need for an accurate network monitoring has become an important challenge to be dealt with accurately. Among the different parameters that can be considered for the traffic monitoring on a path, this paper focuses on the attention on the available bandwidth. Three different techniques and related software implementations aimed at measuring available bandwidth are taken into consideration. The purpose of this work is to provide a performance comparison of the three techniques under different operating conditions. To this aim, a proper measurement station has been set up by the authors.

Social agent: expressions driven by an electronic nose

Abstract: A perceptual system encompasses an important perspective of the interface between a human and an interacting system. In this context, an approach is presented to establish a natural and effective interaction between an operator and a measurement system. The system output acts as a social agent, based on sensory data and presents impressions as facial expressions as well as conclusions in the form of natural language based identification. The proposed method has been evaluated in an experimental perceptual odor system set up using an artificial olfactory system.

An integrated system based on Web and/or WAP framework for remote monitoring and control of industrial processes

Abstract: The aim of this research is to present an integrated system, based on the Web/WAP framework for remote monitoring and control of industrial processes. A Web-server/WAP-gateway located near to the industrial process is responsible for executing the supplied control algorithm, while serving concurrent requests from other client/supervisors. Users can gain access to the system through Web browser or a WAP-enabled mobile phone. The kernel of the integrated system relies on a dataflow programming platform (Labview). The kernel has interfaces to a WAP-server through Active-X, Java-servlets, and Active Server Pages (ASP). The user can remotely: 1) define set points, 2) alter the control algorithm, and 3) monitor parameters of interest. The system has been tested in several common industrial processes and the experimental results reflect the efficacy of the suggested scheme.

Secure Internet access to gateway using secure socket layer

Abstract: Internet is the most widely used medium to access remote sites. Data sent and received using TCP/IP is in plain text format and can be accessed and tampered quite easily and hence provides no data security. Especially, if the data is confidential and access to the gateway server has to be strictly controlled. Although there are several controls and mechanisms that have been thoroughly scrutinized to tackle these problems. In this paper we intend to provide a model that uses SSL to provide a secure channel between client and gateway server. Smart card will be used for client authentication and encryption/decryption of the data.

Audio interface for immersive 3D-audio desktop applications

Abstract: An immersive audio environment for desktop applications is presented. It allows the spatialization of 3D sound fields around an almost free mobile listener. The sound field is reproduced by several loudspeakers positioned along the desktop edges without using head tracking. The loudspeaker signals are derived by using the principle of wave field synthesis approach combined with different panning techniques to overcome the insufficient loudspeaker layout. Virtual sources can be positioned in azimuth, elevation, and distance too. However, the reproduction area around the listener and the possible source space is restricted to a defined area. The quality of the reproduction and the efficiency of different panning algorithms will be investigated.

Static-dynamic mapping in heterogeneous computing environment

Abstract: Appropriate mapping procedures make heterogeneous computing environment especially suitable for the execution of various computer-intensive applications. The paper shows a static dynamic mapping procedure relying on the multicriteria model. Model parameters describe the application, platform, mapping and user. They are divided into static and dynamic ones with three weight levels assigned to them. The described approach ensures optimal initial mapping, but also a quick response to changes in the environment, which is supported by prediction. The described approach is a simplified environment shows improvements in the execution of the test application. Further adjustments are directed towards the implementation in the computational grid.

Symbolic interface for pollutant forecast. An evaluation

Abstract: This paper presents a new 3D visualization system planned to visualize the trend of the hazard index (HI) for a given area emphasizing the correlation between the wind and the concentration o some pollutants, the visualization system is a step for a city-dweller oriented air pollutants forecast system, developed in an industrial town (Taranto - Italy) declared by the national government "territory with high environmental risk". The metaphor, used in this paper is the well-known weather forecast that is as an important aid for everyday life; actually this service is based on a simple 2D interface (video and/or iconic).

LaserPen: a new pointing device for a beam projector

Abstract: We propose a new pointing device for a beam projector that we call a LaserPen system. The basic idea is to detect a laser spot on the screen and use its coordinates to control the GUI cursor so that the two may coincide. While this idea can be easily realized by using a camera and a simple image processing technique, the novel part of our implementation is to share the same optical channel among a projector and a camera so that the focusing and alignment of a camera may be done at the same time as a projector is focused and aligned. In a usability test in comparison with other pointing devices, we could confirm that, due to its directness, the LaserPen system have the potential to become a highly favorable pointing device for a beam projector.

Human interface based on finger gesture recognition using omni-directional image sensor

Abstract: A camera is not a special device for a personal computer. An omni-directional image sensor is a camera that can capture a surrounding image in every direction at a time by using a convex mirror and a video camera. When we grab the omni-directional sensor, the camera captures image of fingers. We propose a human interface based on finger gesture recognition using an omni-directional image sensor. By grabbing the omni-directional image sensor, a user can input commands to the computer. The finger image provides the number of fingers, their area, and their position. The proposed interface recognizes the operations of pushing, pulling, rotating and translating the change of these finger parameters. We implemented the interface for operation of a virtual object using finger gestures to a prototype system.

Hybrid system approach to medical diagnosis

Abstract: Use of the hybrid system approach to medical diagnosis allows all available methodology to contribute to the problem solution In addition, the modularity of this approach facilitates the development of new applications by replacement of the knowledge base, either in terms of expert-supplied information or from learned knowledge derived from databases Since the algorithmic components of the system do not change, it is not necessary to re-evaluate these components The evaluation can therefore focus on the ability of the hybrid system to arrive at accurate decisions for the new application Standard evaluation methodologies based on sensitivity, specificity, and accuracy must be repeated for each new medical application The methodology is illustrated in two applications: diagnosis of cardiac disorders and evaluation of dementia

An information-based criterion for efficient robot map building

Abstract: This paper presents the theoretical aspects and a preliminary experimental validation of a criterion for determining the best observation positions for robot map building, intended as a particular environmental measurement task. The proposed criterion takes into account both the distance traveled and the information gathered by the robot.

Design and experiments of a 6-dimensional spatial tracker for cheap hand motion measurements

Abstract: This paper describes a design experience of a low-cost 6 DOF spatial tracker system where relative low accuracy and relatively long ranges, wireless communication will be achieved by means of low cost accelerometers and gyros with contemporary microprocessor. However, there are two key problems; one is the bias drift problem and the other is the single and double integration of acceleration signal suffers not only from noise but also from nonlinear effects caused by gravity. Several algorithms are proposed to cope with such problems, and verified by some successful experimental results.

Intelligent technique for scene cut detection from MPEG video

Abstract: In this paper we propose a neuro-fuzzy (NF) algorithm that automatically detects the type of MPEG frame at which a clean scene cut occurred. The algorithm is based on detection of the majority of intra-macroblocks and directionality of the two neighboring B-frame motion vector types from the bit stream, it is shown that the method is able to identify the location of the scene cut I-frame, P-frame and each B-frame with a very high success rate.

/spl I.bar/knowscape - a collective knowledge architecture

Abstract: Instead of focusing on negative sides of the freedom observed on the Web, it can be more interesting to consider the Web as a support for the establishment of a collective knowledge. Considering the Web through this kind of perspective makes obvious that tools are missing in order to enhance and develop the awareness of users on the Web as well as the ability to share Web experiences with others. In this paper we propose a 3D Web based tool called /spl I.bar/knowscape that offers a mean to users to share their Web experiences. We will describe concepts that guide our project and technologies and features that are used to try to enhance the Web experience and bring Web browsing to another level of consideration.

Exploring simple visual languages for real time human-computer interaction

Abstract: We want to explore the expressive power of visual languages that can be recognized in real time with off-the-shelf components. Real time constraints imply that we are only able to detect and track color blobs in the image. We test two basic applications: remote control of a mobile robot and gesture based music synthesis. The former requires accuracy in movements, and on the contrary, creativity is important in the latter.

An XML model for use across heterogeneous client-server applications

Abstract: Applications that use directory services or relational databases operate in a client-server model where a client request information from a server, and the server returns a response to the client. These client-server applications typically have a message protocol that is unique to that application. Systems with multiple client-server applications require that there are separate client-server programs that communicate individually with their respective server programs. A need exist to access information from heterogeneous systems in a standard message request-response format. The objective of this paper is to describe an XML model that abstracts the differences in underlying client-server message formats and provides a common XML message interface. The XML messages are parsed through a common XML gateway that decides which application server forward to which message. The generic XML messages are translated to the correct application server format before being sent to the application server.

Investigations on control and perception of virtual distance using loudspeakers

Abstract: The proposed system enables the control of sound sources in a large auditorium both in direction and distance Reproduction of 3D sound fields over loudspeakers where distance coding is taken into account is a rather difficult goal, because different simple and complex properties of a sound event contribute to the perception of distance Similar to the perception of pitch, the perception of distance is bounded in both directions Small deviations concerning far and very short distances can hardly be distinguished Furthermore, caused to be the associated memory, the impression of distance is always biased and relative Therefore, similar to the visual sense, the auditory sense can be easily confused To overcome these problems the reproduces sound field should be identical to the natural one as much as possible As will be shown below, the presented approach is based on the construction of the wavefront curvature in a defined listening area in order to perceive the desired distance The subject of this paper is to find out and validate objective description, which correlates with subjective perception Based on this correlation, optimization criteria can be evaluated to maximize the reconstruction performance in order to control the desired spatial auditory stimuli of perception

Realtime detection and identification of plural speakers using a microphone array

Abstract: Voices are used as primary media in human communication. A human voice is a sound generated by the complex movements of the vocal organs, and is the most important media employed for communication in daily life to logical discussions. A human is able to detect the position of a source sound in 3D space by perceiving the time difference reaching to both ears. Furthermore we can selectively listen to an objective voice in the crowd. This paper presents real time detection and identification of a particular person among plural speakers using a microphone array. The system identifies the position of a particular speaker, and enhances the voice signal selectively.

Design of an access control module for an instrumentation gateway

Abstract: This paper describes some of the preliminary work performed on a resource access control module for an instrumentation gateway. The access control module employs a variation of the popular RBAC (role based access control) scheme described by various authors including Ferraiolo et al. (1999). The gateway has very little security, hence, any user able to log on to the system is able to control any resource. This module aims to implement a pluggable module whereby users are granted access to various parts of the system depending on their user rights whilst giving the administrator a very powerful method of restricting access without sacrificing ease of administration.

Real-time thermal expansion measurement system and the data acquisition and control application software - user interface

Abstract: In order to operate the designed thermal expansion measurement system, a user interface is constructed by using Borland Delphi. This paper presents how the user interface constructed and why it is necessary.

Modeling of arterial pulse waveforms for virtual reconstruction and measurements

Abstract: The subject of this paper is concerned with utilization of virtual reality in biomeasurements. Biomedical signals carry information that is often enclosed in a signal shape. Problems connected with modeling and simulations of the arterial blood pulse waveform are considered. This waveform is a major component of a given plethysmographic signal that may be acquired form various body sites with noninvasive sensors. Basing on selective biooptical properties of human tissues, using optoelectronic sensors allows acquiring photoplethysmographic (PPG) signals. The PPG signal may be considered as the response of a given dynamic system to an input cyclical signal that is quasi-periodical. The known descriptions of PPG attributes are mostly non-parametrical. On the contrary, a way of parametrical description using the methods, which are utilized to identify dynamic systems, is presented in this paper. The ARMAX structure has been utilized as a base of mathematical modeling. The maximum likelihood method was used in identification of investigated PPG signals. Efficiency of the proposed reconstruction procedure has been tested on processing of real signals.

Haptic interface development using a hardware-in-the-loop experimental setup

Abstract: The interaction between the human operator and a virtual environment can be significantly enhanced by a haptic interface. The implementation of a haptic interface requires to account for the dynamics characteristics of the interface components. In this paper, haptic interface development and testing are analyzed using hardware-in-the-loop experimental setups. Two setups are presented, 1DOF and 3DOF. The paper presents issues regarding HIL implementation of haptic interfaces using a nonlinear force feedback from a virtual environment. The results are relevant for the characterization of the performance and the limits of the haptic interface implementations.