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At least 433 records · Page 24Linked to original sources

PubMed2006

Agent based simulations in healthcare.

Agent Based Simulations (ABS) is a relatively recent computer paradigm. As opposed to "top down" conventional computer simulations, the ABS approach is a "bottom-up" modelling technique where a medium to high number of independent agents is modelled. These agents' interactions sometimes cause unexpected "emergent" system behaviour. ABS is particularly suitable in the social context such as healthcare where a large number of human agents interact and co-operate for common goals. Today ABS in the social context is often used together with the recently introduced network analysis techniques and network visualization tools for modelling and simulating social agents within organisations. At Akdeniz University we are starting a number of projects for applying ABS technology in healthcare. In this paper we present two of the ongoing projects in this field. Firstly we have developed a prototype simulator for the long term monitoring of Chronic Obstructive Pulmonary Disease (COPD) as a major public health problem. We present the COPD simulator, its agents, parameters and working principles. Secondly we want to apply ABS and the network analysis techniques to visualise and explore informal social networks amongst staff at the Akdeniz University Hospital to assess and evaluate properties of the organisation in terms of its ability to innovate and share knowledge. In our applications, we primarily aim to use ABS in a web-based platform to create a virtual environment for discussion, visualising and running what-if scenarios to test out various options for managing healthcare, as well as sharing information and creating a virtual community.

Computer Simulation↗

PubMed2004

Comparing effects of 2-D and 3-D visual cues during aurally aided target acquisition.

The aim of the present study was to investigate interactions between vision and audition during a visual target acquisition task performed in a virtual environment. In two experiments, participants were required to perform an acquisition task guided by auditory and/or visual cues. In both experiments the auditory cues were constructed using virtual 3-D sound techniques based on nonindividualized head-related transfer functions. In Experiment 1 the visual cue was constructed in the form of a continuously updated 2-D arrow. In Experiment 2 the visual cue was a nonstereoscopic, perspective-based 3-D arrow. The results suggested that virtual spatial auditory cues reduced acquisition time but were not as effective as the virtual visual cues. Experiencing the 3-D perspective-based arrow rather than the 2-D arrow produced a faster acquisition time not only in the visually aided conditions but also when the auditory cues were presented in isolation. Suggested novel applications include providing 3-D nonstereoscopic, perspective-based visual information on radar displays, which may lead to a better integration with spatial virtual auditory information.

Adolescent↗

PubMed2005

Integration of metabolic networks and gene expression in virtual reality.

MOTIVATION: Metabolic networks combine metabolism and regulation. These complex networks are difficult to understand and visualize due to the amount and diverse types of information that need to be represented. For example, pathway information gives indications of interactions. Experimental data, such as transcriptomics, proteomics and metabolomics data, give snapshots of the system state. Stereoscopic virtual environments provide a true three-dimensional representation of metabolic networks, which can be intuitively manipulated, and may help to manage the data complexity. RESULTS: MetNet3D, a 3D virtual reality system, allows a user to explore gene expression and metabolic pathway data simultaneously. Normalized gene expression data are processed in R and visualized as a 3D plot. Users can find a particular gene of interest or a cluster of genes that behave similarly and see how these genes function in metabolic networks from MetNetDB, a database of Arabidopsis metabolic networks, using animated network graphs. Interactive virtual reality, with its enhanced ability to display more information, makes such integration more effective by abstracting key relationships. AVAILABILITY: MetNet3D and some sample datasets are available at http://www.vrac.iastate.edu/research/sites/metnet/Download/Download.htm. SUPPLEMENTARY INFORMATION: Color snapshots and movies are available at http://www.vrac.iastate.edu/research/sites/metnet/Bioinformatics/SupplementaryInformation.htm.

Algorithms↗

PubMed2004

Acquiring laparoscopic manipulative skills: a virtual tissue dissection training module.

Virtual environments for training manipulative skills in laparoscopic surgery are now well established as research areas. Tissue dissection however has not yet been adequately addressed. We have developed a virtual training module in which the task is to dissect a 3D tissue model using a simulated L-hook. Three metrics have been designed to assess performance. 1) Total deviation of actual cut path from the drawn path. 2) Total contact time between the instrument and tissue. 3) Contact discontinuity. The objective of the research was to design a basic tissue dissection module to train, in part, laparoscopic manipulative skills.

Canada↗

PubMed2002

User satisfaction through empathy and orientation in three-dimensional worlds.

This paper describes a methodology for navigation and exploration assistance intended to enhance user satisfaction when exploring three-dimensional virtual environments. The complexity of such environments often makes navigation and information retrieval difficult, making it necessary to add assistance components to the world in order to turn it easier to manipulate. This methodology uses three-dimensional "intelligent" avatars as interactive guides, along with information-based navigation strategies. The intelligence of the avatars is represented through physical features, behaviors, and knowledge about the user and the environment. These components establish the avatar's architecture. Content personalization according to the user's interest, navigation assistance according to the desired content, and avatar guides that make the virtual place more realistic and pleasant are proposed in order to involve users. A three-dimensional model of the Guggenheim Museum Bilbao, in Spain, is presented as a prototype for the validation of this methodology. In the museum, the guide is represented as a fish that, according to the user's preferences, assumes gender and age. The avatar swims through the museum, following navigation routes that lead through exhibitions previously chosen by the visitor.

Empathy↗

PubMed2003

The VEPSY UPDATED Project: clinical rationale and technical approach.

More than 10 years ago, Tart (1990) described virtual reality (VR) as a technological model of consciousness offering intriguing possibilities for developing diagnostic, inductive, psychotherapeutic, and training techniques that can extend and supplement current ones. To exploit and understand this potential is the overall goal of the "Telemedicine and Portable Virtual Environment in Clinical Psychology"--VEPSY UPDATED--a European Community-funded research project (IST-2000-25323, www.cybertherapy.info). Particularly, its specific goal is the development of different PC-based virtual reality modules to be used in clinical assessment and treatment of social phobia, panic disorders, male sexual disorders, obesity, and eating disorders. The paper describes the clinical and technical rationale behind the clinical applications developed by the project. Moreover, the paper focuses its analysis on the possible role of VR in clinical psychology and how it can be used for therapeutic change.

Computer Simulation↗

PubMed2003

The effect of two types of virtual reality on voluntary center of pressure displacement.

Voluntary movements result in internal perturbations of balance and equilibrium. One variable regulated during movement is the position of the center of pressure (COP). Sensory information from the visual, vestibular and somatosensory systems is used in establishing relevant frames of reference for postural control. In this study, we were interested in determining whether different limitations of COP movement occur when different approaches to delivering virtual environments are used and when visual information incoherent with vestibular and somatosensory information is provided. Eighteen healthy adults completed voluntary lateral reaches under three conditions: continuous lateral reach (CLR), flatscreen virtual reality (FS), and head-mounted display virtual reality (HMD). Reaching behavior was indexed by force plate measures of maximum anterior-posterior and lateral displacement of the COP. The COP movement decreased in the lateral direction in the HMD condition relative to the FS. The maximum range of COP movement in the anterior-posterior direction increased as a function of reaching task with HMD realizing the greatest amount of movement. The lack of an exocentric frame of reference in HMD coherent with information from other sensory systems results in limiting COP movement within the base of support (BOS) in order to decrease the challenge to the postural control system.

Adult↗

PubMed2000

Mapping the zone of eye-height utility for seated and standing observers.

In a series of experiments, we delimited a region within the vertical axis of space in which eye height (EH) information is used maximally to scale object heights, referred to as the "zone of eye height utility" (Wraga, 1999b Journal of Experimental Psychology, Human Perception and Performance 25 518-530). To test the lower limit of the zone, linear perspective (on the floor) was varied via introduction of a false perspective (FP) gradient while all sources of EH information except linear perspective were held constant. For seated (experiment 1a) observers, the FP gradient produced overestimations of height for rectangular objects up to 0.15 EH tall. This value was taken to be just outside the lower limit of the zone. This finding was replicated in a virtual environment, for both seated (experiment 1b) and standing (experiment 2) observers. For the upper limit of the zone, EH information itself was manipulated by lowering observers' center of projection in a virtual scene. Lowering the effective EH of standing (experiment 3) and seated (experiment 4) observers produced corresponding overestimations of height for objects up to about 2.5 EH. This zone of approximately 0.20-2.5 EH suggests that the human visual system weights size information differentially, depending on its efficacy.

Adult↗

PubMedDate not supplied

Virtual colonoscopy: a new approach for colorectal cancer screening.

Virtual endoscopy is the processing of computerized tomography image data to create a virtual environment of the human body to allow diagnosis of disease processes. This new technique allows the observer the opportunity to interact with an image that is artificially generated by the computer. Virtual colonoscopy provides a method for processing data that can display computer images of the colon in a more anatomic life-like format to facilitate image interpretation and improve diagnostic accuracy. The clinical application of virtual endoscopic techniques is also being used with other procedures such as bronchoscopy, gastroscopy, cystoscopy, sinus imaging, virtual angioscopy, and cerebral ventriculography. Current screening recommendations for colorectal cancer are discussed in this article along with methods, advantages, challenges, and future opportunities for virtual colonoscopy.

Colonography, Computed Tomographic↗

PubMed2000

Virtual CT cystoscopy: color mapping of bladder wall thickness.

RATIONALE AND OBJECTIVES: To improve the conspicuity of bladder tumors in a virtual environment, we developed an algorithm for color mapping the thickness of the bladder wall. The purpose of this study was to demonstrate the feasibility of this algorithm as a component of virtual CT cystoscopy. METHODS: Five subjects with a history of superficial transitional-cell carcinoma of the bladder underwent helical CT scanning after insufflation of the bladder with air. Source images were transformed into three-dimensional models, and the thickness of the bladder wall was demarcated by using a new computer algorithm and a fixed color scale. Results were compared with those obtained by conventional cystoscopy. RESULTS: Three tumors, one site of benign wall thickening, and normal wall thickness were correctly identified by using axial source images and virtual cystoscopy with color mapping. CONCLUSIONS: Color mapping of bladder wall thickness is feasible and demonstrates both normal and thickened urothelium. Its value in identification of small or sessile tumors will require further trials.

Aged↗

PubMed2006

High sensitivity to multisensory conflicts in agoraphobia exhibited by virtual reality.

The primary aim of this study was to evaluate the effect of auditory feedback in a VR system planned for clinical use and to address the different factors that should be taken into account in building a bimodal virtual environment (VE). We conducted an experiment in which we assessed spatial performances in agoraphobic patients and normal subjects comparing two kinds of VEs, visual alone (Vis) and auditory-visual (AVis), during separate sessions. Subjects were equipped with a head-mounted display coupled with an electromagnetic sensor system and immersed in a virtual town. Their task was to locate different landmarks and become familiar with the town. In the AVis condition subjects were equipped with the head-mounted display and headphones, which delivered a soundscape updated in real-time according to their movement in the virtual town. While general performances remained comparable across the conditions, the reported feeling of immersion was more compelling in the AVis environment. However, patients exhibited more cybersickness symptoms in this condition. The result of this study points to the multisensory integration deficit of agoraphobic patients and underline the need for further research on multimodal VR systems for clinical use.

Adult↗

PubMed2006

Control of attention and gaze in complex environments.

In natural behavior, fixation patterns are tightly linked to the ongoing task. However, a critical problem for task-driven systems is dealing with unexpected stimuli. We studied the effect of unexpected potential collisions with pedestrians on the distribution of gaze of subjects walking in a virtual environment. Pedestrians on a collision course with the subject were surprisingly ineffective in evoking fixations, especially when subjects were additionally occupied with another task, suggesting that potential collisions do not automatically attract attention. However, prior fixations on pedestrians did increase collision detection performance. Additionally, the detection of potential collisions led to a short-term change in the strategy of looking at subsequent pedestrians. The overall pattern of results is consistent with the hypothesis that subjects typically rely on mechanisms that are initiated top-down to detect unexpected events such as potential collisions. For this to be effective, subjects must learn an appropriate schedule for initiating search through experience with the probabilities of environmental events.

Adult↗

PubMedDate not supplied

Rehabilitation of the head-injured child: basic research and new technology.

The view that brain damage in children is less impairing than equivalent damage in adults is no longer acceptable. However, it is acknowledged that recovery following brain damage, when it does occur, owes much to the plasticity of the brain and that the young brain displays greater plasticity than the mature brain. To maximize brain damage recovery in children we need to focus both on what is known about brain plasticity and how to influence it. Research on environmental enrichment in rats has told us that enforced interaction with a complex environment can both stimulate anatomical and biochemical plasticity and ameliorate some of the behavioural consequences of brain damage. The view that environmental interaction has rehabilitative value also accords with clinical experience. However, the sensory, motor and cognitive consequences of brain damage often conspire to make environmental interaction difficult. One potential solution lies in using computers to generate virtual environments tailored to the precise sensory and motor capacities of the brain-injured child. In this way children may be enabled to benefit from environmental interaction whatever their level of disability. The use of Virtual Reality (VR) in the context of rehabilitation is discussed and relevant work reviewed.

Adult↗

PubMed2006

Fuzzy-oil-drop hydrophobic force field--a model to represent late-stage folding (in silico) of lysozyme.

A model of hydrophobic collapse (in silico), which is generally considered to be the driving force for protein folding, is presented in this work. The model introduces the external field in the form of a fuzzy-oil-drop assumed to represent the environment. The drop is expressed in the form of a three-dimensional Gauss function. The usual probability value is assumed to represent the hydrophobicity distribution in the three-dimensional space of the virtual environment. The differences between this idealized hydrophobicity distribution and the one represented by the folded polypeptide chain is the parameter to be minimized in the structure optimization procedure. The size of fuzzy-oil-drop is critical for the folding process. A strong correlation between protein length and the dimension of the native and early-stage molecular form was found on the basis of single-domain proteins analysis. A previously presented early-stage folding (in silico) model was used to create the starting structure for the procedure of late-stage folding of lysozyme. The results of simulation were found to be promising, although additional improvements for the formation of beta-structure and disulfide bonds as well as the participation of natural ligand in folding process seem to be necessary.

Computer Simulation↗

PubMed2000

[VRATS--Virtual Reality Arthroscopy Training Simulator].

The subject of this paper is a highly interactive medical training system for arthroscopic surgery; this is based on computer graphics and virtual reality (VR) techniques and offers an alternative to conventional training methods. To provide the virtual environment, a realistic 3D representation of the knee joint is derived from 2D medical image data. The use of tracking techniques guarantees an intuitive handling of the surgical instruments. The system allows navigation via a virtual camera and interaction with the virtual anatomical structures. First approaches for the simulation of tissue deformation caused by collisions with the instruments are implemented. One important advantage over conventional training systems is the possibility of verifying the training progress. Work is in progress on the realization of tactile feedback with the aim of providing a higher degree of interactive realism.

Arthroscopy↗

PubMed2025

ShortCake: an integrated platform for efficient and reproducible single-cell analysis.

SUMMARY: Recent advances in single-cell analysis have introduced new computational challenges. Researchers often need to use multiple analysis tools written in different programming languages while managing version conflicts between related packages within a single workflow. For the research community, minimizing the time spent on environment setup and installation issues is essential. We present ShortCake, a containerized platform that integrates a suite of single-cell analysis tools written in R and Python. ShortCake isolates competing Python tools into separate virtual environments that can be easily accessed within a Jupyter notebook. This enables users to effortlessly transition between various environments, including R, even within a single notebook. Additionally, ShortCake offers multiple "flavors," enabling users to select container images tailored to their specific needs. ShortCake provides a unified environment with fixed versions of various tools, thus streamlining workflows, reducing setup time, and improving reproducibility. AVAILABILITY AND IMPLEMENTATION: The ShortCake image is available on DockerHub (https://hub.docker.com/r/rnakato/shortcake) and Zenodo (DOIs: 10.5281/zenodo.17116765 and 10.5281/zenodo.17118158). The source code is available on GitHub (https://github.com/rnakato/ShortCake).

Single-Cell Analysis↗

PubMed2003

Doing play: competency, control, and expression.

This qualitative study investigated the personal experiences of children with cerebral palsy engaging in a virtual reality play intervention program. The study involved in-depth, focused interviews that were conducted with 19 participants aged 8-13 who had a diagnosis of cerebral palsy. A constant comparative inductive method of analysis was used, and several themes emerged. Findings were interpreted using the theory of flow, the theory of self-efficacy, and the model of playfulness in virtual reality computer interactions. The three themes uncovered in the data include (a) doing play, (b) it's my way that matters, and (c) how I see me. The sub-theme safety also emerged. Findings from this study showed that children with physical disabilities are often limited in their play experience compared to their peers without physical disabilities. Children perceived engagement in a virtual reality play intervention program as an enjoyable experience which increased their self-competence and self-efficacy. Participants experienced a sense of control and mastery over the virtual environment and were provided a safe way to explore and challenge their abilities. Participants perceived experiencing flow and reported perceived physical changes and increased social acceptance from both peers and family. These findings provide evidence that virtual reality continues to show promise as a pediatric rehabilitation play intervention tool.

Adolescent↗

PubMed2004

Cybertherapy in practice: the VEPSY updated project.

Rapid and far-reaching technological advances are changing the ways in which people relate, communicate, and live. Technologies that were hardly used ten years ago, such as the Internet, e-mail, and video teleconferencing are becoming familiar methods for diagnosis, therapy, education and training. This is producing an emerging field (cybertherapy) whose focus is the use of communication and information technologies to improve the health care processes. To exploit and understand this potential was the aim of the Telemedicine and Portable Virtual Environment in Clinical Psychology, VEPSY UPDATED, an European Community funded research project (IST-2000-25323, http://www.cybertherapy.info). The chapter describes the clinical and technical rationale behind the cybertherapy applications developed by the project. Further, the actual role of virtual reality in the cybertherapy field is discussed, focusing on the advantages provided by its three different faces: technological, experiential and communicative.

Italy↗