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At least 343 records · Page 19Linked to original sources
PubMed2002

The camera mouse: visual tracking of body features to provide computer access for people with severe disabilities.

The "Camera Mouse" system has been developed to provide computer access for people with severe disabilities. The system tracks the computer user's movements with a video camera and translates them into the movements of the mouse pointer on the screen. Body features such as the tip of the user's nose or finger can be tracked. The visual tracking algorithm is based on cropping an online template of the tracked feature from the current image frame and testing where this template correlates in the subsequent frame. The location of the highest correlation is interpreted as the new location of the feature in the subsequent frame. Various body features are examined for tracking robustness and user convenience. A group of 20 people without disabilities tested the Camera Mouse and quickly learned how to use it to spell out messages or play games. Twelve people with severe cerebral palsy or traumatic brain injury have tried the system, nine of whom have shown success. They interacted with their environment by spelling out messages and exploring the Internet.

Activities of Daily Living↗
PubMed1995

Image-oriented rule generating tool for medical knowledge base.

This paper describes an automatic programming tool for the end users in the medical knowledge representation. When end users work with the rule generating tool (RGT) that we have designed, they can represent an idea using an Image-oriented interface such as a picture, movie, audio reference or two dimensional bar code. Such representations can be valuable tools for medical study, diagnosis, decision making and treatment monitoring to supplement the expertise of medical personnel. The RGT will automatically generate rules in the logic programming language Prolog and then add them to the knowledge base.

Algorithms↗
PubMedDate not supplied

Long-term preservation of a beating heart in an artificial environment.

The natural heart could be preserved in the beating state, with appropriate afterload, for more than 24 hrs if supported by blood compatible artificial organs and biomedical engineering techniques. An artificial environment was developed using this philosophy. The system was constructed from four subsystems: circulatory, respiratory, metabolic, and environmental. In the circulatory subsystem, diastolic pressure was held at 70 to 100 mmHg by computer aided peripheral resistance, and a left ventricular assist device (LVAD) could be added when cardiac function was weakened. The respiratory subsystem was composed of an artificial lung and computer aided gas mixer for O2, CO2, and air, which kept blood PO2 and PCO2 within physiologic levels. In the metabolic subsystem, glucose and insulin were injected by infusion pump so as to maintain blood sugar within 100 to 200 mg/dl, whereas the environmental system preserved the isolated heart at 37 degrees C in a sterile water bath. Goats' hearts were connected to this system, and continued to beat for a maximum of 24 hours.

Animals↗
PubMed1991

MACSPEC--a software system for fully automatic processing and analysis of large series of NMR spectra.

In vivo NMR spectroscopy often accumulates a large number of spectra (typically 100 individual files or even more) to follow metabolic changes with high time-resolution. The analysis of these spectra is very time-consuming for the spectroscopist and, furthermore, it requires the spectrometer's computer, needed for control of experiments. Here we report the software system MACSPEC developed for automatic processing and analysis of large series of individual NMR spectra on a peripheral personal computer. With this software the spectrometer's computer is kept available for experiments, and the necessary interaction of the spectroscopist is limited to a definition of the processing conditions at the beginning of the data analysis.

Electronic Data Processing↗
PubMed1999

Aging, motor control, and the performance of computer mouse tasks.

Because of the increased presence of computers in work and everyday life and the demographic "graying" of America, there is a need for interface designs that promote accessibility for older people. This study examined age differences in the performance of basic computer mouse control techniques. An additional goal of the study was to examine the influence of age-related changes in psychomotor abilities on mouse control. A total of 60 participants in 3 age groups (20-39 years, 40-59 years, and 60-75 years) performed 4 target acquisition tasks (pointing, clicking, double-clicking, and dragging) using a computer mouse. The data indicated that the older participants had more difficulty performing mouse tasks than the younger participants. Differences in performance attributable to age were found for the more complex tasks (clicking and double-clicking). Furthermore, age-related changes in psychomotor abilities were related to age differences in performance. We discuss applications to computer interface designs. Actual or potential applications of this research include specifications for computer mouse design to accommodate older populations.

Adult↗
PubMed1995

A tool for matching physically impaired people with suitable technical aids: the merits and demerits of a laser disk consultation tool.

We are developing a tool for matching physically impaired people with suitable technical aids;w this tool will also provide specific and comprehensive information to users. According to the user's physical abilities and situations (indicated when using a "mouse"), specific instructions with dynamic images are displayed on the screen. The hardware of this system will be constructed with the laser¿disk system (Pioneer Laser Active, CLD¿A100). The software for drawing dynamic images is a two dimensional animation software (Animation Stand). The difficulties of developing this system are (1) Collecting every possible pattern without exclusion and constructing the comprehensive information frame for providing specific advises, and (2) Drawing a large number of dynamic animations. The merits of this tool are (1) High quality image and quick response time, (2) Excellent presentation ability, (3) A user friendly interface.

Activities of Daily Living↗
PubMed2002

Strategic navigation of two-dimensional alley mazes: comparing capuchin monkeys and chimpanzees.

Planning is an important component of cognition that contributes, for example, to efficient movement through space. In the current study we presented novel two-dimensional alley mazes to four chimpanzees and three capuchin monkeys to identify the nature and efficiency of planning in relation to varying task parameters. All the subjects solved more mazes without error than expected by chance, providing compelling evidence that both species planned their choices in some manner. The probability of making a correct choice on mazes designed to be more demanding and presented later in the testing series was higher than on earlier, simpler mazes (chimpanzees), or unchanged (capuchin monkeys), suggesting microdevelopment of strategic choice. Structural properties of the mazes affected both species' choices. Capuchin monkeys were less likely than chimpanzees to take a correct path that initially led away from the goal but that eventually led to the goal. Chimpanzees were more likely to make an error by passing a correct path than by turning onto a wrong path. Chimpanzees and one capuchin made more errors on choices farther in sequence from the goal. Each species corrected errors before running into the end of an alley in approximately 40% of cases. Together, these findings suggest nascent planning abilities in each species, and the prospect for significant development of strategic planning capabilities on tasks presenting multiple simultaneous or sequential spatial relations. The computerized maze paradigm appears well suited to investigate movement planning and spatial perception in human and nonhuman primates alike.

Animals↗
PubMed1994

[Computer-assisted, improved evaluation of Comberg images with three-dimensional graphic reconstruction].

BACKGROUND: Small metallic foreign bodies may easily be identified by conventional x-ray. The Comberg shell is a useful tool to discriminate between extra-respectively intraocular localization of the foreign body. However, poor results are common when evaluating the x-ray films. METHODS: We have improved evaluation of the radiographs by means of a program for a personal computer, regarding the following aspects: To avoid errors of measurement the relevant points of the radiograms are read by a digitizer-tableau. The different projection failure of the lateral respectively posteroanterior x-ray is calculated separately. For the calculation of the modell the true axial length of the eye is considered. CONCLUSION: A three dimensional image from varying points of view gives an instructive impression of the foreign body and its relation to structures of the eye. Handling of the presented computer program is easy. It standardizes analysis of the Comberg radiograms.

Computer Graphics↗
PubMed1995

A comparison of tactile, auditory, and visual feedback in a pointing task using a mouse-type device.

A mouse was modified to add tactile feedback via a solenoid-driven pin projecting through a hole in the left mouse button. An experiment is described using a target selection task under five different sensory feedback conditions ('normal', auditory, colour, tactile, and combined). No differences were found in overall response times, error rates, or bandwidths; however, significant differences were found in the final positioning times (from the cursor entering the target to selecting the target). For the latter, tactile feedback was the quickest, normal feedback was the slowest. An examination of the spatial distributions in responses showed a peaked, narrow distribution for the normal condition, and a flat, wide distribution for the tactile (and combined) conditions. It is argued that tactile feedback allows subjects to use a wider area of the target and to select targets more quickly once the cursor is inside the target. Design considerations for human-computer interfaces are discussed.

Attention↗
PubMed2002

Concordance between task and interface rotational and translational control improves ground vehicle performance.

Research in various areas of human-system interaction suggests the importance of examining the similarities and dissimilarities between tasks and the interfaces used to complete them. Specifically, the theory of cognitive fit suggests that human problem solvers will perform better when the data and data displays they use to complete a task match some characteristic of that task. An experiment was performed that extends the theory of cognitive fit to the realm of human performance on motor tasks. Participants completed several virtual vehicle control motor tasks that consisted of rotational and translational control components. The tasks were performed with user interfaces that either combined or separated rotational and translational control. The tasks were of two types: control of either rotation or translation changes but not both concurrently, or simultaneous control of combined rotation and translation changes. The results indicate that task performance was better when the characteristics of the interface matched the characteristics of the task. Actual or potential applications of this research include constructing ground vehicle interface controls that are designed specifically based on the characteristics of the task for which they are to be used, such as primarily driving fast and in a straight line (e.g., on a highway) versus primarily driving slowly with much turning (e.g., on a city street).

Adolescent↗
PubMed2002

System for assisted mobility using eye movements based on electrooculography.

This paper describes an eye-control method based on electrooculography (EOG) to develop a system for assisted mobility. One of its most important features is its modularity, making it adaptable to the particular needs of each user according to the type and degree of handicap involved. An eye model based on electroculographic signal is proposed and its validity is studied. Several human-machine interfaces (HMI) based on EOG are commented, focusing our study on guiding and controlling a wheelchair for disabled people, where the control is actually effected by eye movements within the socket. Different techniques and guidance strategies are then shown with comments on the advantages and disadvantages of each one. The system consists of a standard electric wheelchair with an on-board computer, sensors and a graphic user interface run by the computer. On the other hand, this eye-control method can be applied to handle graphical interfaces, where the eye is used as a mouse computer. Results obtained show that this control technique could be useful in multiple applications, such as mobility and communication aid for handicapped persons.

Activities of Daily Living↗
PubMed1994

[Telemetric transmission system for in vivo measurement of the stress load of an internal spinal fixator].

For stabilizing fractures of the spine, a number of implantable devices are available. However, not much is known about the loads acting on these devices. In order to measure the forces and moments within the implant, the Dick internal fixation device was modified and fitted out with a hermetically sealed inductively powered telemetry unit. An integrated 8-channel telemetry chip was specially developed to measure the signals of six strain gauge sensors, the temperature of the implant and the supply voltage. Since the internal fixation devices are always implanted in pairs, two telemetry units are operated at the same time. This article details the function of the implanted electronic circuit and the external system components.

Adult↗
PubMed1997

EEG-based communication: evaluation of alternative signal prediction methods.

Individuals can learn to control the amplitude of EEG activity in specific frequency bands over sensorimotor cortex and use it to move a cursor to a target on a computer screen. For one-dimensional (i.e., vertical) cursor movement, a linear equation translates the EEG activity into cursor movement. To translate an individual's EEG control into cursor control as effectively as possible, the intercept in this equation, which determines whether upward or downward movement occurs, should be set so that top and bottom targets are equally accessible. The present study compares alternative methods for using an individual's previous performance to select the intercept for subsequent trials. In offline analyses, five different intercept selection methods were applied to EEG data collected while trained subjects were moving the cursor to targets at the top or bottom edge of the screen. In the first two methods-moving average, and weighted sum-a single intercept was selected for the entire 1-2 sec period of each trial. In the other three methods-blocked moving average, blocked weighted sum, and blocked recursive sum (a variation of the weighted sum)-an intercept was selected for each 200-ms segment of the trial. The results from these methods were compared in regard to their balance between upward and downward movements and their consistency of performance across trials. For all subjects combined, the five methods performed similarly. However, performance across subjects was more consistent for the moving average, blocked moving average, and blocked recursive sum methods than for the weighted sum and blocked weighted sum methods. Due to its consistent performance and its computational simplicity, the moving average method, using the five most recent pairs of top and bottom trials, appears to be the method of choice.

Adult↗
PubMed1994

How many screens does a CT workstation need?

A considerable number of prototype and commercial workstations have been developed during the last 10 years for electronic display of computed tomographic (CT) images during clinical interpretation. These CT workstations have varied widely in the number and size of monitors available for the display of the medical images ranging from a single 1,024 x 1,204-pixel monitor, to eight 2,500 x 2,000-pixel monitors. Image display times also have varied considerably, ranging from as fast as .11 seconds, to as slow as 26 seconds to fill a single monitor. No consensus has formed in the workstation community with regard to display area and response time requirements. To address this issue, we have constructed a time-motion model of CT interpretation. Model accuracy is experimentally verified with three workstations as well as with the film alternator. In general, CT interpretations with an electronic workstation become faster as display area increases and display time decreases. Results can be used by workstation designers and purchasers to roughly estimate differences in interpretation speeds among contending CT workstation designs.

Computer Peripherals↗
PubMed1997

A microcomputer program for automated neuronal spike detection and analysis.

A system for on-line spike detection and analysis based on an IBM PC/AT compatible computer, written in TURBO PASCAL 6.0 and using commercially available analog-to-digital hardware is described here. Spikes are detected by an adaptive threshold which varies as a function of signal mean and its variability. Since the threshold value is determined automatically by the signal-to-noise ratio analysis, the user is not actively involved in controlling its level. This program has been reliably used for the detection and analysis of the spike discharge of vestibular system afferent neurons. It generates the interval-joint distribution graph, the interval histogram, the autocorrelation function, the autocorrelation histogram, and phase-space graphs, thus, providing a complete set of graphical and statistical data for the characterization of the dynamics of neuronal spike activity. Data can be exported to other software such as Excel, Sigmaplot and MatLab, for example.

Ambystoma↗