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In a recent BAMS article, it is argued that community-based Open Source Software (OSS) could foster scientific progress in weather radar research, and make weather radar software more affordable, flexible, [...]

The objective of this study was to investigate whether the appearance of virtual human models influences observers when judging a working posture. A task in which a manikin is manually assembling a car battery was used in the experiment. In total, 16 different pictures were presented to the subjects. All pictures had the same background, but included a unique posture and manikin appearance combination. 24 subjects consisting of manufacturing managers, simulation engineers and ergonomists were asked to rate and rank the pictures. The results showed that the virtual human model appearance influenced subjects when they rated pictures one by one: a more realistic manikin was rated higher than the identical posture visualized with a less natural appearance. This appearance effect was not seen when subjects ranked the pictures while looking at all of them at the same time. The study demonstrates that the human modelling tool used when showing and visually evaluating results makes a difference. To minimize subjective effects, a combination of visualizations and objective ergonomic assessment methods is recommended. Keywords: Manikin appearance; Ergonomics visualization; Virtual manufacturing

The article presents the partitioning method for providing latency to users in distributed virtual environment systems. The system throughput is maximized and receives satisfactory latency for providing quality service.

Real-time human-computer interaction plays an important role in virtual-environment (VE) applications. Such interaction can be improved by detecting and reacting to the user's head motion. Today's VE systems use head-mounted inertial sensors to update and spatially stabilize the image displayed to a user through a head-mounted display. Since motion can only be detected after it has already occurred, latencies in the stabilization scheme can only be reduced but never eliminated. Such latencies slow down manual control, cause inaccuracies in matching real and virtual objects through a half-transparent display, and reduce the sense of presence. This paper presents novel methods for reducing VE latencies by anticipating future head motion based on electromyographic (EMG) signals originating from the major neck muscles and head kinematics; it also reports results for anticipation of 17.5 and 35 ms. Features extracted from the EMG signals are used to train a neural network in mapping EMG data, given present head kinematics, into future head motion. The trained network is then used in real time for head-motion anticipation, which gives the VE system the time advantage necessary to compensate for the inherent latencies. The main contribution of this work is the use of EMG energy and bounded head acceleration as the key input/output information, which results in improved performance compared to the previous work. Index Terms--Electromyogram, head-mounted display, neural networks, pattern recognition, virtual environment.

Byline: M. Emin Aydin (1), Terence C. Fogarty (1) Keywords: Parallel simulated annealing; multi-agent systems; job-shop scheduling; distributed resource machine Abstract: In this paper, a parallel implementation of the modular simulated annealing algorithm for classical job-shop scheduling is presented. The implementation is for a multi agent system running on the distributed resource machine, which is a novel, scalable, distributed virtual machine based on Java technology. The problems tackled are well known, difficult benchmarks, widely used to measure the efficiency of metaheuristics with respect to both the quality of the solutions and the central processing unit time. The empirical results obtained show that the method proposed is successful in comparison with a sequential version of modular simulated annealing algorithm and other methods described in the literature. Author Affiliation: (1) School of Computing, Information Systems and Mathematics, South Bank University, 103 Borough Road, London, SE1 0AA, UK Article History: Registration Date: 29/12/2004

Virtual reality techniques are now more and more widely used in the field of surgical training. However, the realism of the simulation devices requires a good knowledge of the mechanical behavior of the living organs. To provide perioperative measurement of laparoscopic surgical operations, we equipped a conventional operating grasper with a force sensor and a position sensor. The entire apparatus was connected to a PC that controlled the real-time data acquisition. After calibrating the sensors, we conducted three series of in vivo measurements on animals under video control. A standardized protocol was set up to perform various surgical gestures in a reproducible manner. Under these conditions, we can assess an original tool for a quantitative approach of surgical gestures' mechanics. The preliminary results will be extended by measurements during other operations and with other surgical instruments. The in vivo quantification of the mechanical interactions between operating instruments and anatomical structures is of great interest for the introduction of the force feedback in virtual surgery, for the modeling of the mechanical behavior of living organs, and for the design of new surgical instruments. This quantification of manipulations opens new prospects in the evaluation of surgical practices. Index Terms--Biomechanics, in vivo measurements, surgical gestures.

Byline: CHELL A. ROBERTS (1), MAGED M. DESSOUKY (2), YASSER M. DESSOUKY (1) Keywords: Virtual factory; real-time control; batch-chemical manufacturing; object-oriented Abstract: This paper presents a virtual plant modeller (VPMOD), which formally characterizes and integrates chemical product designs, batch-chemical equipment (plants), the real-time scheduling of chemical batches, and the control of chemical transport through the plant. These models provide a framework for agile batch-chemical manufacturing that has the ability to reroute and control chemical product flow automatically in a flexible plant subject to unexpected events, such as changes in demand patterns and equipment failure. A formal logic model is generated to control the actual system events, which are non-deterministic. A simulation environment in VPMOD is used to validate schedules and control logic based on plant models supplied by industry. The formal models have been implemented in an object-oriented language. Author Affiliation: (1) Department of Industrial and Management Systems Engineering, Arizona State University, Tempe, Arizona, 85287-5906 (2) Department of Industrial and Systems Engineering, University Southern California, Los Angeles, CA, 90089-0193 Article History: Registration Date: 29/09/2004

This paper presents preliminary results of the development of a virtual flight data recorder (VFDR) for commercial airliners. Federal Aviation Administration (FAA) regulations, currently being revised, mandate the recording of 11 dynamic parameters, not including the control surface deflections. The absence of these data can be critical for crash investigation purposes. This paper proposed the introduction of a VFDR based on a neural network simulator (NNS) and a neural network reconstructor (NNR). The NNS is trained, using flight data for the particular aircraft, to simulate any desired control surface deflections (or any other parameter of interest not recorded by the FDR), minimizing a cost function based on the differences between the available data from the FDR and the output from the NNS. The VFDR scheme has been introduced, tested, and validated with flight data from a Boeing 737-300 with an FDR with extended recording capabilities showing accurate reconstruction of the control surface deflections' time histories. The VFDR can be considered a tool for crash investigations where control surface failures are believed to be a factor.

The challenge of virtual libraries is to make access of information readily available to all users. Special librarians have the responsibility to continually improve their skills and be knowledgeable in their field to be able to perform their functions., Or Plus ca Change, Plus C'est La Meme Chose In this issue of Special Libraries, we examine the concept of the library without walls or the virtual library from the [...]

Ann Arbor, MI-based Mechanical Dynamics markets ADAMS, which is a virtual prototyping software which aids engineers in designing aircrafts using a more efficient and cost-saving technique. With the software, aircraft designers can create a prototype without spending millions of dollars on manufacturing. Virtual prototyping allows engineers to view the actual product, to test how the parts and assemblies fit and assess the aircraft's motion.