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Results for “Simulation Training”

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At least 1,189 records · Page 66Linked to original sources

PubMed2005

High-speed face recognition based on discrete cosine transform and RBF neural networks.

In this paper, an efficient method for high-speed face recognition based on the discrete cosine transform (DCT), the Fisher's linear discriminant (FLD) and radial basis function (RBF) neural networks is presented. First, the dimensionality of the original face image is reduced by using the DCT and the large area illumination variations are alleviated by discarding the first few low-frequency DCT coefficients. Next, the truncated DCT coefficient vectors are clustered using the proposed clustering algorithm. This process makes the subsequent FLD more efficient. After implementing the FLD, the most discriminating and invariant facial features are maintained and the training samples are clustered well. As a consequence, further parameter estimation for the RBF neural networks is fulfilled easily which facilitates fast training in the RBF neural networks. Simulation results show that the proposed system achieves excellent performance with high training and recognition speed, high recognition rate as well as very good illumination robustness.

Algorithms↗

PubMed2006

Surgical dexterity after a 'night out on the town'.

BACKGROUND: This study examines the effect of alcohol intake on surgical dexterity immediately after and the morning after alcohol intake and minimal sleep deprivation by simulating a typical night out on the town. METHODS: Five surgeons (all men, aged 31-40 years) were trained on a laparoscopic surgical simulator (minimally invasive surgical trainer-virtual reality) to reach a desired standard of performance. Three experimental settings were used: (i) a control night with no alcohol and full night's sleep; (ii) a sham night out (sleep deprived) without alcohol; and (iii) a night out with alcohol ad libitum. The parameters recorded were the average time taken to carry out a task, error rate, average diathermy time and diathermy (damage) time to main object. Comparisons between baseline readings, those in the middle of the night and those of the following morning were made by applying ANOVA methods after logarithmic transformation of the data. RESULTS: The candidates consumed, on average, 10.33 units (range, 6-15 units) of alcohol and had 0.86% (range, 0.71-1.1%) of breath alcohol levels and an average of 3.75 h (range, 3-5 h) of sleep after a typical night out. The morning-after breath alcohol levels were 0%. There was significant deterioration in performance, as measured by all indicators, immediately after alcohol consumption. The adverse effects on time taken to complete the task and total diathermy time were still apparent the morning after. The sham night out appeared to affect only 'time parameters'. No significant changes in performance were seen in the control setting. CONCLUSION: Both alcohol consumption and sleep deprivation adversely affect the ability to carry out surgical procedures. Our simulation study suggests that the adverse effects of alcohol intake persist the following morning.

Alcohol Drinking↗

PubMed2004

Identifying and training non-technical skills for teams in acute medicine.

The aviation domain provides a better analogy for the "temporary" teams that are found in acute medical specialities than industrial or military teamwork research based on established teams. Crew resource management (CRM) training, which emphasises portable skills (for whatever crew a pilot is rostered to on a given flight), has been recognised to have potential application in medicine, especially for teams in the operating theatre, intensive care unit, and emergency room. Drawing on research from aviation psychology that produced the behavioural marker system NOTECHS for rating European pilots' non-technical skills for teamwork on the flightdeck, this paper outlines the Anaesthetists Non-Technical Skills behavioural rating system for anaesthetists working in operating theatre teams. This taxonomy was used as the design basis for a training course, Crisis Avoidance Resource Management for Anaesthetists used to develop these skills, based in an operating theatre simulator. Further developments of this training programme for teams in emergency medicine are outlined.

Allied Health Personnel↗

PubMed1999

Scoring performance on computer-based patient simulations: beyond value of information.

As computer based clinical case simulations become increasingly popular for training and evaluating clinicians, approaches are needed to evaluate a trainee's or examinee's solution of the simulated cases. In 1997 we developed a decision analytic approach to scoring performance on computerized patient case simulations, using expected value of information (VOI) to generate a score each time the user requested clinical information from the simulation. Although this measure has many desirable characteristics, we found that the VOI was zero for the majority of information requests. We enhanced our original algorithm to measure potential decrements in expected utility that could result from using results of information requests that have zero VOI. Like the original algorithm, the new approach uses decision models, represented as influence diagrams, to represent the diagnostic problem. The process of solving computer based patient simulations involves repeated cycles of requesting and receiving these data from the simulations. Each time the user requests clinical data from the simulation, the influence diagram is evaluated to determine the expected VOI of the requested clinical datum. The VOI is non-zero only it the requested datum has the potential to change the leading diagnosis. The VOI is zero when the data item requested does not map to any node in the influence diagram or when the item maps to a node but does not change the leading diagnosis regardless of it's value. Our new algorithm generates a score for each of these situations by modeling what would happen to the expected utility of the model if the user changes the leading diagnosis based on the results. The resulting algorithm produces a non-zero score for all information requests. The score is the VOI when the VOI is non-zero It is a negative number when the VOI is zero.

Algorithms↗

PubMed1997

A decision analytic method for scoring performance on computer-based patient simulations.

As computer based clinical case simulations become increasingly popular for training and evaluating clinicians, approaches are needed to evaluate a trainee's or examinee's solution of the simulated cases. We developed a decision analytic approach to scoring performance on computerized patient case simulations. We developed decision models for computerized patient case simulations in four specific domains in the field of infectious disease. The decision models were represented as influence diagrams. A single decision node represents the possible diagnoses the user may make. One chance node represents a probability distribution over the set of competing diagnoses in the simulations. The value node contains the utilities associated with all possible combinations of diagnosis and disease. All relevant data that the user may request from the simulation are represented as chance nodes with arcs to or from the diagnosis node and/or each other. Probabilities in the decision model were derived from the literature, where available, or expert opinion. Utilities were assessed by standard gamble from clinical experts. The process of solving computer based patient simulations involves repeated cycles of requesting data (history, physical examination or laboratory) and receiving these data from the simulations. Each time the user requests clinical data from the simulation, the influence diagram is evaluated with and without an arc from the corresponding chance node to the decision node. The difference in expected utility between the two solutions of the influence diagram represents the expected value of information (VOI) from the requested clinical datum. The ratio of the expected VOI from the data requested and the expected value of perfect information about the diagnosis is a normative measure of the quality of each of the user's data requests. This approach provides a continuous measure of the quality of the user's data requests in a way that is sensitive to the previous data collected. The score distinguishes serious from minor misdiagnoses. And the same influence diagram can be used to evaluate performance on multiple simulations in the same clinical domain.

Computer Simulation↗

PubMed2006

Modeling of muscle motor unit innervation process correlation and common drive.

Concurrently active motor units (MUs) of a given muscle can exhibit a certain degree of synchronous firings, and a certain degree of common variation in their firing rates. The former property is referred to as motor unit synchrony in the literature, which is termed motor unit innervation process (MUIP) correlation in this study. The latter is referred to as motor unit common drive and can be quantified by the common drive coefficient, which is the correlation coefficient between the smoothed firing rates of the two MUs. Both properties have important roles and implications in the generation and resulting characteristics of the myoelectric signal and for the development of signal processing algorithms in myoelectric signal (MES) applications. In order to study these implications and characteristics, in this paper estimation procedures are developed to quantify the degree of MUIP correlation and common drive as functions of physiological parameters. Also, the interaction between MUIP correlation and motor unit common drive is studied in a physiologically realistic simulation model. Neurons modeled by Hodgkin-Huxley systems form the framework of the simulation model in which excitation and synaptic characteristics can be modified. MUIP correlation and common drive degree and interaction are studied through a number of simulations. To support the simulation results, experimental in vivo motor unit trains were collected at low levels of contraction from 11 subjects, and decomposed into the constituent unit trains giving 50 concurrently active motor unit pairs. The simulation demonstrated that the innervation process correlation coefficient is controlled primarily by the postsynaptic conductance, gsyn, and was less than 0.05 mS/cm2 for realistic values of gsyn. The common drive was found to be controlled by the exciting neuron input with no statistically significant interaction between it and the MUIP correlation. The experimental data gave results in close agreement with those of the simulation.

Action Potentials↗

PubMed2005

Acute sleep responses in a normobaric hypoxic tent.

PURPOSE: Sleeping in a hypoxic environment is becoming increasingly popular among athletes attempting to simulate a "live high, train low" training regime. The purpose of this study was to investigate the acute effects (one night) of sleeping in a normobaric hypoxic tent (NH) (PO(2) = 110 mm Hg approximately 2500 m) upon markers of sleep physiology and quality, compared with sleep in a normal ambient environment (BL) (PO(2) = 159 mm Hg approximately sea level) and sleep in a normobaric normoxic tent (NN) (PO(2) = 159 mm Hg). METHODS: Eight male recreational athletes (age 34.5 +/- 6.9 yr; stature 169.1 +/- 8.7 cm; mass 69.3 +/- 8.2 kg; VO(2max) 56.4 +/- 8.3 mL.kg(-1).min(-1)) participated in the study using a randomized, double-blind crossover design. Polysomnographic studies were undertaken to measure sleep stages, arterial oxygen saturation (SpO(2)), heart rate (HR), and the Respiratory Disturbance Index (RDI). The Leeds Sleep Evaluation Questionnaire (LSEQ) was used to measure subjective sleep quality. RESULTS: NH (89.9 +/- 4.8%) resulted in a significantly lower (P < 0.05) SpO(2) compared with both BL (95.7 +/- 1.5%) and NN (93.5 +/- 4.0%). Heart rate was significantly higher (P < 0.05) in NH (51.5 +/- 7.6 beats.min(-1)) compared with NN (48.3 +/- 6.9 beats.min(-1)) but was similar versus BL (50.3 +/- 4.3 beats.min(-1)). RDI (counts.h) and RDI (total counts) were lowest in BL (3.5 +/- 2.5; 18.1 +/- 7.9) and highest in NH (36.8 +/- 42.7; 221.9 +/- 254.5). The difference in RDI (counts.h(-1) and total counts) between NH and BL was significant (P < 0.05). The LSEQ revealed that subjects' "behavior following waking" score was significantly (P < 0.05) lower in NH (40.9 +/- 9.2) compared with BL (52.3 +/- 8.3). CONCLUSION: This study presents evidence that sleep in a normobaric hypoxic tent at a simulated altitude of 2500 m may affect sleep parameters in some individuals. This type of analysis may be useful in the early identification of poorly responding individuals to simulated altitude environments.

Adult↗

PubMed2005

Analysis of the applicability of artificial neural networks for studying blood plasma: determination of magnesium ion concentration as a case study.

Artificial neural networks are suggested for use in predicting metal ion concentration in human blood plasma. Simulated and available experimental data are used to train the artificial neural network. Particularly, using 850 simulated samples, the network predicted the magnesium-free ion concentration with an average error smaller than 1%. Clinical data recently reported for 20 patients were considered and the artificial neural network predicted the concentration of free magnesium ion with an average error of about 6%. Overall, the approach of using artificial neural networks as an alternative or complementary strategy to deal with the analysis of human blood plasma can be useful for clinical diagnostics, if there is sufficient data to train the artificial neural network.

Humans↗

PubMed2001

Improving operative performance using a laparoscopic hernia simulator.

BACKGROUND: Traditionally, the acquisition of surgical skill has occurred entirely in the operating room. To meet the expanding challenges of cost containment and patient safety, novel methods of surgical training utilizing ex-vivo workstations are being developed. The purpose of our study was to evaluate the impact of a laparoscopic training curriculum on surgical residents' operative performance. METHODS: Twenty-one surgery residents completed baseline laparoscopic total extraperitoneal (TEP) hernia repairs. Operative performance was evaluated using a validated global assessment tool. Each resident was then randomized to a control group or a trained group. A CD ROM, video, and simulator were used for training. At the end of the study, each resident's operative performance was again evaluated. RESULTS: Improvement was significantly greater in the trained group in five of the eight individual global assessment areas as well as the composite score (P <0.05). Questionnaire data suggested that training resulted in improved understanding of the TEP hernia repair (P = 0.01) and an increased willingness to offer the operation to patients with nonrecurrent unilateral hernias (P = 0.02). CONCLUSIONS: A multimodality laparoscopic TEP hernia curriculum improves residents' knowledge of the TEP hernia repair and comfort in performing the procedure, and may also improve actual operative performance.

Clinical Competence↗

PubMed2000

Simulation in anesthesia: the merits of large simulators versus small simulators.

Anesthesia simulation is generally perceived as involving large simulators that provide a limited number of operating room scenarios, especially crisis management. The scope of both anesthesia and flight simulation is much wider, and this review summarizes the range of the former. The areas where simulation has been used include training, education and science. The diversity of its uses may surprise the reader. The models that are used in simulations are important, and these are discussed in part of the discussion. As a result of the current imbalance in perception, I emphasize the merits of small simulators at the expense of large simulators.

Journal Article↗

PubMed1995

Simulation in computer of the mechanical ventilator Servo 900C made by Siemens Elema.

In our country, Intensive Care Units (ICU) for both adults and children include medical equipment of high technology that saves the lives of patients in critical condition. Many of these patients for different pathologies need the use of a mechanical ventilator which keeps the patient's respiration and allows the medical staff to assist them with other means. In practice, there are a lot of different situations that the medical staff have to face and make adequate decisions that will help save the patients' lives. In this case, the mechanical ventilator must be used, requiring a great deal of experience acquired along many years of work. The mechanical ventilator SERVO 900C made by Siemens Elema is available in all ICUs; this equipment is used for the treatment of more critical patients due to his reliability and technical features. Based on this fact, a simulator was designed to help train the less experienced staff in the use of the ventilator and to allow them to face real case simulations, making decisions that will be adequate or wrong with no risk to the patient's life. In this way, they would acquire the necessary knowledge on how to use the equipment in real-life situations. The created system displays the control panel of the ventilator allowing the user to interact. The control panel includes both analogical and digital devices that show different parameters and also the gases mixer which is connected to the equipment. During the work, the user can access a calculator to facilitate the adjustment of some parameters in case any calculation is needed. The system is divided into modules. The module "Exercises" permits you to choose one out of a set and solve it by means of the adjustment of the controls; this answer is analyzed and warning messages are displayed in case a control has been set incorrectly. The aim of these exercises is that the users learn how to handle the equipment by parts and are conceived for a sequence of question-answer. The module "Problems" describes the condition of a given patient which must be treated with the ventilator. The user will then simulate his performance in the adjustment of it. The sequence question-answer will change dynamically according to the evolution previously previewed for the patient by the professor. The simulator has a set of acoustic and visual alarms which are activated during the occurrence of different anomalies. These alarms work according to the professor's will at the moment of planning the lesson. The module "Information" gives the user the possibility of consulting topics about the equipment such as: functions, patient's safety, installation, clinical judgment and location of failures. In the last module "Options" the user defines the files (exercises or problems) he is going to use as well as the directory of work and the initialization file. The system uses pull-down menus, providing a context-sensitive on screen help with information about the function of each control and how to handle it. For the preparation of the files of exercises and problems only Servo editor can be used; this editor works independently from the simulator. The system requires a PC IBM Compatible with 640 kb RAM, MS-DOS operating system, and VGA color display. We consider that with the implementation this system the user can gain experience and knowledge about the use of the ventilator before he faces real situations.

Adult↗

PubMed2003

Surgical simulators.

The use of emerging virtual reality technology for surgical skill training has recently attracted a lot of attention. Computerized surgical simulators offer a significant potential for providing a realistic and configurable training environment that bridges the gap between basic training and performing the actual interventions on patients. This paper summarizes the current state of this rapidly developing field and analyses the major problems to be addressed in order to make this technology an indispensable tool for routine clinical training and education.

Journal Article↗

PubMed2006

Attempted establishment of proficiency levels for laparoscopic performance on a national scale using simulation: the results from the 2004 SAGES Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) learning center study.

BACKGROUND: The Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) has been well validated as a training device for laparoscopic skills. It has been demonstrated that training to a level of proficiency on the simulator significantly improves operating room performance of laparoscopic cholecystectomy. The purpose of this project was to obtain a national standard of proficiency using the MIST-VR based on the performance of experienced laparoscopic surgeons. METHODS: Surgeons attending the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) 2004 Annual Scientific Meeting who had performed more than 100 laparoscopic procedures volunteered to participate. All the subjects completed a demographic questionnaire assessing laparoscopic and MIST-VR experience in the learning center of the SAGES 2004 meeting. Each subject performed two consecutive trials of the MIST-VR Core Skills 1 program at the medium setting. Each trial involved six basic tasks of increasing difficulty: acquire place (AP), transfer place (TP), traversal (TV), withdrawal insert (WI), diathermy task (DT), and manipulate diathermy (MD). Trial 1 was considered a "warm-up," and trial 2 functioned as the test trial proper. Subject performance was scored for time, errors, and economy of instrument movement for each task, and a cumulative total score was calculated. RESULTS: Trial 2 data are expressed as mean time in seconds in Table 2. CONCLUSION: Proficiency levels for laparoscopic skills have now been established on a national scale by experienced laparoscopic surgeons using the MIST-VR simulator. Residency programs, training centers, and practicing surgeons can now use these data as guidelines for performance criterion during MIST-VR skills training.

Adult↗

PubMed2003

Microsurgery simulators in virtual reality: review.

Surgical training is undergoing a rapid transformation, which has been influenced by advances in computer modeling. Increased pressure to reduce the use of animals in technical training has led to a new approach in teaching microsurgery. This new technology may prove to be a cost-effective, portable, and nonhazardous way forward in microsurgical training. This paper reviews the current state of available technological models used in microsurgical training. In doing so, we review articles from the latest journals and authenticated Internet websites to compare and contrast these various methods. Finally, we look at the specific technique that has potential impact on the future modeling of microsurgical techniques.

Computer Simulation↗

PubMed2005

VSOne, a virtual reality simulator for laparoscopic surgery.

The introduction of computer-based training systems for laparoscopic surgery has increased the training quality and made the learning effect measurable with objective criteria. This paper introduces VSOne as a fully-featured virtual reality training system for laparoscopic surgery. VSOne utilizes the state-of-the-art in virtual reality techniques, soft tissue simulation and haptic device control and guarantees realistic training possibilities for various laparoscopic procedures. An authoring software helps to create individual simulation models easily within the shortest time based on real patient data using standardized data formats. We have developed several Basic Task Training (BTT) modules to improve dexterity and complex Surgical Procedure Task (SPT) modules for full training of laparoscopic procedures such as cholecystectomy, tubal sterilization and myomectomy. VSOne has been evaluated in a comparative study with classic training methods and has shown the typical learning curves for inexperienced trainees and the transferability of the learning effect to the real-world situation.

Journal Article↗

PubMed2005

The instructional effectiveness of a web-based audiometry simulator.

With distance learning becoming more of a reality than a novelty in many undergraduate and graduate training programs, web-based clinical simulations can be identified as an instructional option in distance education that has both a sound pedagogical foundation and clinical relevance. The purpose of this article is to report on the instructional effectiveness of a web-based pure-tone audiometry simulator by undergraduate and graduate students in speech-language pathology. Graduate and undergraduate majors in communication sciences and disorders practiced giving basic hearing tests on either a virtual web-based audiometer or a portable audiometer. Competencies in basic testing skills were evaluated for each group. Results of our analyses of the data indicate that both undergraduate and graduate students learned basic audiometric testing skills using the virtual audiometer. These skills were generalized to basic audiometric testing skills required of a speech language pathologist using a portable audiometer.

Adult↗

PubMed1989

Use of small-caliber polytetrafluoroethylene (Gore-Tex) grafts in microsurgical training.

We present the use of polytetrafluoroethylene (PTFE) graft material as a microsurgical training model that better simulates live vessel repairs. PTFE grafts have mechanical advantages over polyethylene or silicone tubing in that they better mimic the "feel" of an arterial vessel wall, thus allowing the student to perfect counterpressor maneuvers before attempting live vessel repairs. Saving the PTFE "repairs" for later comparison and study provides the student with positive feedback that is not possible with living models. This cost-effective model has helped to shorten our directed teaching program and has reduced the use of laboratory animals.

Anastomosis, Surgical↗

PubMed1993

Information theoretic analysis of action potential trains. I. Analysis of correlation between two neurons.

A crosscorrelational method of action potential trains has been proposed, based on information theory. Two information theoretic quantities, mutual information and channel capacity, were calculated from a pair of action potential trains for detecting a crosscorrelation and estimating synaptic connectivity. The method was compared with conventional ones, using action potential trains obtained by the simulation of a neuron model. This method was shown to have the advantages to more easily find a weak but significant crosscorrelation and to give better estimation of synaptic connectivity independent of the firing probability of a presynaptic neuron.

Action Potentials↗