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At least 595 records · Page 33Linked to original sources

PubMed2001

Utah Virtual Lab: JAVA interactivity for teaching science and statistics on line.

The Utah on-line Virtual Lab is a JAVA program run dynamically off a database. It is embedded in StatCenter (www.psych.utah.edu/learn/statsampler.html), an on-line collection of tools and text for teaching and learning statistics. Instructors author a statistical virtual reality that simulates theories and data in a specific research focus area by defining independent, predictor, and dependent variables and the relations among them. Students work in an on-line virtual environment to discover the principles of this simulated reality: They go to a library, read theoretical overviews and scientific puzzles, and then go to a lab, design a study, collect and analyze data, and write a report. Each student's design and data analysis decisions are computer-graded and recorded in a database; the written research report can be read by the instructor or by other students in peer groups simulating scientific conventions.

Humans↗

PubMed1999

View dependence in scene recognition after active learning.

Human spatial encoding of three-dimensional navigable space was studied, using a virtual environment simulation. This allowed subjects to become familiar with a realistic scene by making simulated rotational and translational movements during training. Subsequent tests determined whether subjects could generalize their recognition ability by identifying novel-perspective views and topographic floor plans of the scene. Results from picture recognition tests showed that familiar direction views were most easily recognized, although significant generalization to novel views was observed. Topographic floor plans were also easily identified. In further experiments, novel-view performance diminished when active training was replaced by passive viewing of static images of the scene. However, the ability to make self-initiated movements, as opposed to watching dynamic movie sequences, had no effect on performance. These results suggest that representation of navigable space is view dependent and highlight the importance of spatial-temporal continuity during learning.

Adult↗

PubMed1996

High-power graphic computers for visual simulation: a real-time--rendering revolution.

Advances in high-end graphics computers in the past decade have made it possible to render visual scenes of incredible complexity and realism in real time. These new capabilities make it possible to manipulate and investigate the interactions of observers with their visual world in ways once only dreamed of. This paper reviews how these developments have affected two preexisting domains of behavioral research (flight simulation and motion perception) and have created a new domain (virtual environment research) which provides tools and challenges for the perceptual psychologist. Finally, the current limitations of these technologies are considered, with an eye toward how perceptual psychologist might shape future developments.

Aircraft↗

PubMed2001

Of mice and men: virtual Hebb-Williams mazes permit comparison of spatial learning across species.

We developed a computer-generated virtual environment to test humans, for the first time, on the Hebb-Williams mazes. The goal was to provide a standardized test that could be used to directly compare human performance with that of C57BL/6J mice performing in real versions of the mazes. Such a comparison seems crucial if conclusions regarding genetic manipulations of rodents are to be mapped onto human cognitive disorders. The learning curves across species were strikingly similar, lending support to the rodent model of human spatial memory. Humans learned faster than rodents in both the acquisition and the test portions of the protocol, and females of both species were less efficient in solving these problems than males. These results represent the first modern comparison of human and rodent learning that uses the same test of spatial problem solving.

Adult↗

PubMed1996

Geometric and physical representations for a simulator of hepatic surgery.

Despite the large interest in simulators of minimally invasive surgery, it is still unclear to what extent simulators can achieve the task of training medical students in surgical procedures. The answer to that question is certainly linked to the realism of displays and force-feedback systems and to the level of interaction provided by the computer system. In this paper, we describe the virtual environment for anatomical and surgical training on the liver, currently under construction at INRIA. We specifically address the problems of geometric representation and physical modeling and their impact on the two aforementioned problems: realism and real-time interaction.

Computer Simulation↗

PubMed1996

Linking anatomy and physiology in modeling respiratory mechanics.

We present an integrated 3D virtual environment for the quantitative modeling of the anatomy and the physiology of the pulmonary system. Our approach formally integrates 3D deformable object modeling with conventional models of respiratory mechanics. We demonstrate quantitatively, aspects of the behavior of the respiratory system qualitatively known to clinicians, such as normal quiet breathing and an open sucking chest wound. Our methodology is general and can be used to model both the anatomy and the physiology at many levels of detail. Another important aspect of our approach is that based on our previously developed computer vision techniques we can make such a simulation patient specific. The usefulness of such a system is manifold. Medical education, surgical planning, disease diagnosis are some of the many areas such a system can be applied.

Computer Simulation↗

PubMed1997

Simulated casualties and medics for emergency training.

The MediSim system extends virtual environment technology to allow medical personnel to interact with and train on simulated casualties. The casualty model employs a three-dimensional animated human body that displays appropriate physical and behavioral responses to injury and/or treatment. Medical corpsmen behaviors were developed to allow the actions of simulated medical personnel to conform to both military practice and medical protocols during patient assessment and stabilization. A trainee may initiate medic actions through a mouse and menu interface; a VR interface has also been created by Stansfield's research group at Sandia National Labs.

Computer Simulation↗

PubMed1997

Virtual reality in the operating room of the future.

In cooperation with the Max-Delbrück-Centrum/Robert-Rössle-Klinik (MDC/RRK) in Berlin, the Fraunhofer Institute for Computer Graphics is currently designing and developing a scenario for the operating room of the future. The goal of this project is to integrate new analysis, visualization and interaction tools in order to optimize and refine tumor diagnostics and therapy in combination with laser technology and remote stereoscopic video transfer. Hence, a human 3-D reference model is reconstructed using CT, MR, and anatomical cryosection images from the National Library of Medicine's Visible Human Project. Applying segmentation algorithms and surface-polygonization methods a 3-D representation is obtained. In addition, a "fly-through" the virtual patient is realized using 3-D input devices (data glove, tracking system, 6-DOF mouse). In this way, the surgeon can experience really new perspectives of the human anatomy. Moreover, using a virtual cutting plane any cut of the CT volume can be interactively placed and visualized in realtime. In conclusion, this project delivers visions for the application of effective visualization and VR systems. Commonly known as Virtual Prototyping and applied by the automotive industry long ago, this project shows, that the use of VR techniques can also prototype an operating room. After evaluating design and functionality of the virtual operating room, MDC plans to build real ORs in the near future. The use of VR techniques provides a more natural interface for the surgeon in the OR (e.g., controlling interactions by voice input). Besides preoperative planning future work will focus on supporting the surgeon in performing surgical interventions. An optimal synthesis of real and synthetic data, and the inclusion of visual, aural, and tactile senses in virtual environments can meet these requirements. This Augmented Reality could represent the environment for the surgeons of tomorrow.

Computer Simulation↗

PubMed1998

The virtual temporal bone.

The human temporal bone is a 3-dimensionally complex portion of the skull that contains delicate and vital anatomic structures imbedded within dense bone. Current teaching tools have proven to be only marginally adequate for the needs of the aspiring otologic surgeon in learning this anatomy. A variety of image processing and reconstruction techniques were used to reconstruct an anatomically accurate 3-dimensional model of the human temporal bone from serial histologic sections. Using CAVE technology, the model can be manipulated in a stereoscopic virtual environment so that it can be studied from any viewpoint, greatly simplifying the task of learning this anatomy. Applications in surgical planning and Internet based teaching are discussed.

Anatomy↗

PubMed1998

Force interactions in laparoscopic simulations: haptic rendering of soft tissues.

Research in the area of computer assisted surgery and surgical simulation has mainly focused on developing 3D geometrical models of the human body from 2D medical images, visualization of internal structures for educational and preoperative surgical planning purposes, and graphical display of soft tissue behavior in real time. Conveying to the surgeon the touch and force sensations with the use of haptic interfaces has not been investigated in detail. We have developed a set of haptic rendering algorithms for simulating "surgical instrument--soft tissue" interactions. Although the focus of the study is the development of algorithms for simulation of laparoscopic procedures, the developed techniques are also useful in simulating other medical procedures involving touch and feel of soft tissues. The proposed force-reflecting soft tissue models are in various fidelities and have been developed to simulate the behavior of elastically deformable objects in virtual environments. The developed algorithms deal directly with geometry of anatomical organs, surface and compliance characteristics of tissues, and the estimation of appropriate reaction forces to convey to the user a feeling of touch and force sensations.

Algorithms↗

PubMed1998

Virtual reality for palliative medicine.

The technology of virtual reality (VR) offers several advantages in the field of medicine because it enables us to practice medical procedures repeatedly, and can provide a variety of experiences by using virtual organs in different patients. It also aids in learning about a clinical procedure and facilitates objective evaluation by a supervisor. In the field of clinical oncology, a virtual environment can be useful for simulating surgery, diagnosing cancer invasion, obtaining informed consent or enhancing patient education, and for clinical communication using network-based VR. This technology can also be used to improve a patient's living conditions and to treat the psychological problems and/or stress of cancer patients. In the present chapter advanced VR research for palliative medicine at the National Cancer Center Hospital Japan is described and discussed.

Computer Simulation↗

PubMed1998

Current uses of virtual reality for children with disabilities.

Technological advances, including the use of virtual reality, have contributed enormously to improving the treatment, training, and quality of life of children with disabilities. This paper describes the advantages of VR for children with disabilities, how VR can minimize the effects of a disability, the role of VR in training and skills enhancement, and how social participation and the child's quality of life may be improved through the use of VR. Examples from published literature and Internet sites are given of current and completed projects which focus on improving the lives of children with disabilities. The research describing the efficacy of knowledge and skills transfer from a virtual environment to the real world are examined in relation to children with disabilities. Finally, the current limitations and future directions of VR for children with disabilities are considered.

Child↗

PubMed1998

Virtual reality in neuroscience: a survey.

Some research projects have begun to test the possibility of using Virtual Environments (VEs) for research in neuroscience, neurosurgery and for the study and rehabilitation of human cognitive and functional activities. In fact, VEs let users navigate and interact with computer-generated 3-D environments in real time, allowing for the control of complex stimulus presentations. VEs enable the neuroscientist to present a wide variety of controlled stimuli and to measure and monitor a wide variety of responses made by the user. This paper highlights recent and ongoing research related to the applications of VEs in the neuroscience arena. In particular it focuses on the European and US applications in this field.

Artificial Intelligence↗

PubMedDate not supplied

[Virtual reality: a simple joke or therapeutic instrument?].

Virtual reality is a relatively new application for rehabilitative neurology, and achieve many successes in assessment and treatment of CNS damages. The Authors describe a prototype computer simulation for virtual environment reconstruction to assess the fundamental living skills of every day dedicated to persons in which CNS injury was occurred.

Central Nervous System Diseases↗

PubMed1999

Virtual hand laboratory meets endoscopic surgery.

We describe two recent research projects: the Virtual Hand Laboratory, and Remote Manipulation in Endoscopic Surgery. The Virtual Hand Laboratory (VHL) is a prototype experimental tool for investigating human visuomotor coordination for object manipulation in augmented and virtual environments. The Remote Manipulation in Endoscopic Surgery (RMES) project examined surgeon's use of viewing and manipulating technologies in laparoscopic surgery, both in clinical and experimental settings. Current research brings together these two parallel research projects (VHL and RMES), for applications in planning and real-time execution of surgical procedures as well as for surgical training. We outline our research directions and detail current activities on superposition of display space on the workspace for the surgeon's hands.

Endoscopy↗

PubMed1999

Interactive volume visualizations for synchronous and asynchronous remote collaboration.

The value of information acquisition is not simply to acquire data at increased precision, but to make these data both available and usable to as many specialists as possible. We have developed a working prototype for intuitive realtime interaction over the Internet. Current scenarios include use by expert head and neck surgeons, for use in preoperative assessment of head and neck cancers, and remote synchronous collaboration scenarios such as expert-expert and expert-referring physician. This prototype demonstrates a shared virtual environment that allows multiple users to interactively manipulate large volumetric data sets across long distances. The system is easily extensible to many other applications that utilize discrete data sampling and thus is readily extensible to a wide range of scientific investigations.

Head and Neck Neoplasms↗

PubMed1999

Haptic rendering of isosurfaces directly from medical images.

Virtual environments for surgical training, planning and rehearsal have the potential to significantly enhance patient treatment and diagnosis. Haptic feedback devices provide forces to the physician through a manipulator, simulating palpation, scalpel cuts, or retraction of tissue. While haptics have been studied in other fields, medical applications of haptics remain in their infancy. We propose a method of haptically rendering isosurfaces (representing hard structures) directly from anatomical datasets rather than through traditional intermediate graphical representations such as polygons. Our algorithm determines an implicit surface representation of a volumetric isosurface on the fly, and renders the structure using standard haptic algorithms to calculate the forces felt by the user. This approach has the advantage of providing easy access to the rich volume dataset containing the actual anatomy. By relating Hounsfield units to density, haptic rendering has the ability to provide different resistances based on the tissue type being rendered. We developed and tested our algorithm using a quadric implicit surface, a common primitive in computer graphics, and have applied it to a variety of anatomical image datasets. Our paper describes the algorithm in sufficient detail to facilitate reproduction by others.

Algorithms↗

PubMed1999

Computer-assisted planning and simulation of hip operations using virtual three-dimensional models.

In this paper a new software system for virtual preoperative planning and simulation of hip operations is presented. The system simulates the endoprosthetic reconstruction of the hip joint with hemipelvic replacement for bone tumor patients and supports the individual design of anatomically adaptable, modular prostheses. Three-dimensional models of the patient's hip are generated based on CT data. The surgeon simulates the operation and defines the position and shape of the custom-made endoprosthesis. Stereoscopic visualization and 3D input devices facilitate the navigation and interaction in the virtual environment. Special visualization techniques like texture mapping, color coding of quantitative parameters or transparency support the determination of the correct position and shape of the prosthesis. Furthermore, the system can be used for patient information or educational tasks.

Arthroplasty, Replacement, Hip↗