Validity of the modified RULA for computer workers and reliability of one observation compared to six.

Awkward body posture while typing is associated with musculoskeletal disorders (MSDs). Valid rapid assessment of computer workers' body posture is essential for the prevention of MSD among this large population. This study aimed to examine the validity of the modified rapid upper limb assessment (mRULA) which adjusted the rapid upper limb assessment (RULA) for computer workers. Moreover, this study examines whether one observation during a working day is sufficient or more observations are needed. A total of 29 right-handed computer workers were recruited. RULA and mRULA were conducted. The observations were then repeated six times at one-hour intervals. A significant moderate correlation (r = 0.6 and r = 0.7 for mouse and keyboard, respectively) was found between the assessments. No significant differences were found between one observation and six observations per working day. The mRULA was found to be valid for the assessment of computer workers, and one observation was sufficient to assess the work-related risk factor.

Role of Ergonomic Improvements in Decreasing Repetitive Stress Injuries and Promoting Well-Being in a Radiology Department.

RATIONALE AND OBJECTIVES: To determine if ergonomic improvements in a radiology department can decrease repetitive stress injuries (RSIs), advance ergonomics knowledge, and improve well-being. MATERIALS AND METHODS: Radiologists in an academic institution were surveyed regarding physician wellness, workstations, RSIs, and ergonomics knowledge before and after interventions over 1 year. Interventions included committee formation, education, wrist pads and wireless mice, broken table and chair replacement, and cord organization. Mann-Whitney U test was used for analysis. RESULTS: Survey response was 40% preinterventions (59/147), and 42% (66/157) postinterventions. Preinterventions, of radiologists with RSI history, 17/40 (42%) reported the RSI caused symptoms which can lead to burnout, and 15/40 (37%) responded their RSI made them think about leaving their job. Twenty-three of 59 (39%) radiologists had an active RSI preinterventions. Postinterventions, 9/25 (36%) RSI resolved, 13/25 (52%) RSI improved, and 3/25 (12%) RSI did not improve. RSI improvements were attributed to ergonomic interventions in 19/25 (76%) and therapy in 2/25 (8%). Radiologists who thought their workstation was designed with well-being in mind increased from 9/59 (15%) to 52/64 (81%). The percentage of radiologists knowing little or nothing about ergonomics decreased from 15/59 (25%) to 5/64 (8%). After ergonomics interventions, more radiologists thought the administration cared about safety and ergonomics, equipment was distributed fairly, and radiologists had the ability to ask for equipment (p < .01). Fifty-three of 64 (83%) of radiologists after interventions said improving workstation ergonomic design contributed to well-being. CONCLUSION: Ergonomic improvements in radiology can decrease RSIs, advance ergonomics knowledge, and improve well-being.

The performance of computer input devices in a vibration environment.

This study investigates the performance of a touch screen, mouse and trackball in a motion environment. A Stewart motion platform was used to generate a six-degree-of-freedom motion environment. Participants were placed in an environment where vehicle vibration was simulated. Tasks were used according to Fitts' Law to obtain the movement time, error rate, index of performance and throughput of each input device. The results showed that during static conditions, the touch screen gave the best results. However, in the vibration environment, the mouse gave the best results. The trackball is the worst of the three. The error rate and end-point variation tends to increase for the touch screen in the vibration environment. STATEMENT OF RELEVANCE: This study investigates the performance of a pointing device in a vibration environment. The results showed that during static conditions, the touch screen gave the best results. However, in the vibration environment, the mouse gave the best results. The track ball is the worst of the three. This research achievement can help human-computer interaction design in various dynamic environments such as in sea and land vehicles.

Calibration, registration, and synchronization for high precision augmented reality haptics.

In our current research we examine the application of visuo-haptic augmented reality setups in medical training. To this end, highly accurate calibration, system stability, and low latency are indispensable prerequisites. These are necessary to maintain user immersion and avoid breaks in presence which potentially diminish the training outcome. In this paper we describe the developed calibration methods for visuo-haptic integration, the hybrid tracking technique for stable alignment of the augmentation, and the distributed framework ensuring low latency and component synchronization. Finally, we outline an early prototype system based on the multimodal augmented reality framework. The latter allows colocated visuo-haptic interaction with real and virtual scene components in a simplified open surgery setting.

A method for achieving an order-of-magnitude increase in the temporal resolution of a standard CRT computer monitor.

As the frequency of a flickering light is increased, the perception of flicker is replaced by the perception of steady light at what is known as the critical flicker fusion threshold (CFFT). This threshold provides a useful measure of the brain's information processing speed, and has been used in medicine for over a century both for diagnostic and drug efficacy studies. However, the hardware for presenting the stimulus has not advanced to take advantage of computers, largely because the refresh rates of typical monitors are too slow to provide fine-grained changes in the alternation rate of a visual stimulus. For example, a cathode ray tube (CRT) computer monitor running at 100Hz will render a new frame every 10 ms, thus restricting the period of a flickering stimulus to multiples of 20 ms. These multiples provide a temporal resolution far too low to make precise threshold measurements, since typical CFFT values are in the neighborhood of 35 ms. We describe here a simple and novel technique to enable alternating images at several closely-spaced periods on a standard monitor. The key to our technique is to programmatically control the video card to dynamically reset the refresh rate of the monitor. Different refresh rates allow slightly different frame durations; this can be leveraged to vastly increase the resolution of stimulus presentation times. This simple technique opens new inroads for experiments on computers that require more finely-spaced temporal resolution than a monitor at a single, fixed refresh rate can allow.

[A particular anthropometric method for the study of accessibility of a workstation]. / Un particolare approccio antropometrico per lo studio della raggiungibilità di una postazione cassa.

One of the main factors which can involve musculo-skeletal disorders is the assumption of awkward postures. These lasts can be caused, in some cases, by a no-suitable collocation of some devices which are indispensable for the work. It is possible to evaluate if the chosen collocation is adequate or not by studying the accessibility of the workstation with a special regard for the accessibility of the devices placed inside the workstation. EN ISO 14738:2002 is a specific standard which has been adopted in Italy as UNI EN ISO 14738:2004. This standard gives some useful requirements, in terms of accessibility, to design a workstation at no-mobile machinery. In this study, the authors have analyzed a check out workstation by following the requirements described in UNI EN ISO 14738:2004. Critical aspects, related to the organization both of the work activities either of the workstation, have been highlighted taking into account standard criteria. Finally the authors make a new design of the check out workstation trying to optimize device collocation in order to reduce awkward postures. The new configuration has been investigated by applying the criteria mentioned in the standard.

A professional and cost effective digital video editing and image storage system for the operating room.

We propose an easy-to-construct digital video editing system ideal to produce video documentation and still images. A digital video editing system applicable to many video sources in the operating room is described in detail. The proposed system has proved easy to use and permits one to obtain videography quickly and easily. Mixing different streams of video input from all the devices in use in the operating room, the application of filters and effects produces a final, professional end-product. Recording on a DVD provides an inexpensive, portable and easy-to-use medium to store or re-edit or tape at a later time. From stored videography it is easy to extract high-quality, still images useful for teaching, presentations and publications. In conclusion digital videography and still photography can easily be recorded by the proposed system, producing high-quality video recording. The use of firewire ports provides good compatibility with next-generation hardware and software. The high standard of quality makes the proposed system one of the lowest priced products available today.

Tagging of Test Tubes with Electronic p-Chips for Use in Biorepositories.

A system has been developed to electronically tag and track test tubes used in biorepositories. The system is based on a light-activated microtransponder, also known as a "p-Chip." One of the pressing problems with storing and retrieving biological samples at low temperatures is the difficulty of reliably reading the identification (ID) number that links each storage tube with the database containing sample details. Commonly used barcodes are not always reliable at low temperatures because of poor adhesion of the label to the test tube and problems with reading under conditions of frost and ice accumulation. Traditional radio frequency identification (RFID) tags are not cost effective and are too large for this application. The system described herein consists of the p-Chip, p-Chip-tagged test tubes, two ID readers (for single tubes or for racks of tubes), and software. We also describe a robot that is configured for retrofitting legacy test tubes in biorepositories with p-Chips while maintaining the temperature of the sample below -50°C at all times. The main benefits of the p-Chip over other RFID devices are its small size (600 × 600 × 100 µm) that allows even very small tubes or vials to be tagged, low cost due to the chip's unitary construction, durability, and the ability to read the ID through frost and ice.

Optical density variations in CT films and their effect on image quality.

It was recently reported that optical density (OD) variations were observed in CT films printed with a laser camera, depending on the printing format and the frame position within the film. The purpose of the present study was to investigate if these variations are common to both laser and dry-film printers and if the different OD settings along with day-to-day and frame-to-frame variations may affect the image quality. Eight laser and five dry-film printers installed at 12 different CT facilities were tested. For each one, the SMPTE test pattern was printed on all frames of a film using the same printing format. The ODs of the 0%, 10%, 40% and 70% patches of the 11-step greyscale of the SMPTE patterns were measured with a densitometer in all frames, while all films were examined on a viewing box to assess subjectively the image quality by visual inspection of the test pattern. A wide range of OD settings and variations were recorded. Frame-to-frame variations in the same film of up to 0.19, 0.15 and 0.21 OD, were observed for contrast index (CI, the OD difference of patches 10% and 70%), speed index (SI, the OD of patch 40%) and maximum OD (OD(max), the OD of patch 0%), respectively. The variations were not always of the same magnitude, nor always followed the same pattern, even for printers of the same model. Considering all films and frames, the CI ranged from 1.26 to 1.74, the SI from 0.68 to 1.43 and the OD(max) from 2.5 to 3.11 OD, well beyond the proposed settings and tolerances of 1.55+/-0.15, 1.15+/-0.1 and 2.45+/-0.1 given in the literature for CI, SI and OD(max), respectively. Despite these large differences, the various problems that were identified in image quality from the visual inspection of the films could not be directly attributed to OD settings, as films with similar CI, SI and OD(max) presented quite different image quality levels. Therefore, for routine quality control, thorough visual inspection of the SMPTE test pattern provides all the necessary information about the imaging chain status.

Photograph-based ergonomic evaluations using the Rapid Office Strain Assessment (ROSA).

The Rapid Office Strain Assessment (ROSA) was developed to assess musculoskeletal disorder (MSD) risk factors for computer workstations. This study examined the validity and reliability of remotely conducted, photo-based assessments using ROSA. Twenty-three office workstations were assessed on-site by an ergonomist, and 5 photos were obtained. Photo-based assessments were conducted by three ergonomists. The sensitivity and specificity of the photo-based assessors' ability to correctly classify workstations was 79% and 55%, respectively. The moderate specificity associated with false positive errors committed by the assessors could lead to unnecessary costs to the employer. Error between on-site and photo-based final scores was a considerable ∼2 points on the 10-point ROSA scale (RMSE = 2.3), with a moderate relationship (ρ = 0.33). Interrater reliability ranged from fairly good to excellent (ICC = 0.667-0.856) and was comparable to previous results. Sources of error include the parallax effect, poor estimations of small joint (e.g. hand/wrist) angles, and boundary errors in postural binning. While this method demonstrated potential validity, further improvements should be made with respect to photo-collection and other protocols for remotely-based ROSA assessments.

Audiophile hardware in vision science; the soundcard as a digital to analog converter.

The design objective was to develop an inexpensive digital to analog (D/A) converter for use in vision science. Soundcards are hardware units that can be integral or can be added to a computer to add sound capability. A soundcard contains D/A converters designed to work in the audio frequency range, typically 20-20,000 Hz. Soundcard outputs are high-pass filtered and thus do not convey sub-audio frequency or dc information. It is possible to circumvent this design feature by programming the desired output waveform as an amplitude modulation of a high frequency carrier, and then demodulating the soundcard output. The circuit, using a 20 kHz carrier, provides precise D/A conversion for the frequency range relevant for vision experiments, dc to 100 Hz, using inexpensive readily available components. The specific application was for 8 channels of D/A conversion using a Macintosh computer running under OS X. The software needed to program stimuli was created using CoreAudio, a library for programming sounds in OS X. Using soundcards on other platforms would not be a problem, as long as there exists a low level library that would enable the wave table to be filled.

Use of Digital Pens for Rapid Epidemiologic Data Collection During a Foodborne Outbreak Investigation.

OBJECTIVE: Public health investigations require rapid assessment, response, and initiation of control measures. In 2012, the New Hampshire Department of Health and Human Services used digital pens to rapidly acquire epidemiologic data during a gastrointestinal illness outbreak. METHODS: Menus were obtained and a standard questionnaire was administered to exposed persons using digital pens. Questionnaire data were downloaded into an electronic file for analysis. RESULTS: Sixty-nine (74%) of 93 exposed persons completed a questionnaire. Of 6389 data entries made on digital paper, 218 (3%) required correction; of these, 201 (92%) involved a free-form variable and 17 (8%) involved a check-box variable. Digital pens saved an estimated 5 to 6 hours of data-entry time. CONCLUSIONS: This outbreak provided an opportunity to assess the value of digital pens for decreasing data-entry burden and allowing more timely data analysis in an emergent setting. Depending on the size of the outbreak and complexity of the survey, there is likely a threshold when use of digital pens would provide a clear benefit to outbreak response. As new technology becomes available for use in emergency preparedness settings, public health agencies must continuously review and update response plans and evaluate investigation tools to ensure timely disease control and response activities.

A fast flexible ink-jet printing method for patterning dissociated neurons in culture.

We present a new technique that uses a custom-built ink-jet printer to fabricate precise micropatterns of cell adhesion materials for neural cell culture. Other work in neural cell patterning has employed photolithography or "soft lithographic" techniques such as micro-stamping, but such approaches are limited by their use of an un-alterable master pattern such as a mask or stamp master and can be resource-intensive. In contrast, ink-jet printing, used in low-cost desktop printers, patterns material by depositing microscopic droplets under robotic control in a programmable and inexpensive manner. We report the use of ink-jet printing to fabricate neuron-adhesive patterns such as islands and other shapes using poly(ethylene) glycol as the cell-repulsive material and a collagen/poly-D-lysine (PDL) mixture as the cell-adhesive material. We show that dissociated rat hippocampal neurons and glia grown at low densities on such patterns retain strong pattern adherence for over 25 days. The patterned neurons are comparable to control, un-patterned cells in electrophysiological properties and in immunocytochemical measurements of synaptic density and inhibitory cell distributions. We suggest that an inexpensive desktop printer may be an accessible tool for making micro-island cultures and other basic patterns. We also suggest that ink-jet printing may be extended to a range of developmental neuroscience studies, given its ability to more easily layer materials, build substrate-bound gradients, construct out-of-plane structure, and deposit sources of diffusible factors.

Timing of EEG-based cursor control.

Recent studies show that humans can learn to control the amplitude of electroencephalography (EEG) activity in specific frequency bands over sensorimotor cortex and use it to move a cursor to a target on a computer screen. EEG-based communication could be a valuable new communication and control option for those with severe motor disabilities. Realization of this potential requires detailed knowledge of the characteristic features of EEG control. This study examined the course of EEG control after presentation of a target. At the beginning of each trial, a target appeared at the top or bottom edge of the subject's video screen and 1 sec later a cursor began to move vertically as a function of EEG amplitude in a specific frequency band. In well-trained subjects, this amplitude was high at the time the target appeared and then either remained high (i.e., for a top target) or fell rapidly (i.e., for a bottom target). Target-specific EEG amplitude control began 0.5 sec after the target appeared and appeared to wax and wane with a period of approximately 1 sec until the cursor reached the target (i.e., a hit) or the opposite edge of the screen (i.e., a miss). Accuracy was 90% or greater for each subject. Top-target errors usually occurred later in the trial because of failure to reach and/or maintain sufficiently high amplitude, whereas bottom-target errors usually occurred immediately because of failure to reduce an initially high amplitude quickly enough. The results suggest modifications that could improve performance. These include lengthening the intertrial period, shortening the delay between target appearance and cursor movement, and including time within the trial as a variable in the equation that translates EEG into cursor movement.

Design features of alternative computer keyboards: a review of experimental data.

Design of computer keyboards no longer is limited to the flat keyboards that are typically shipped with personal computers. Keyboards now exist that are split into halves and these halves can be slanted away from each other (creating a triangle between the halves), sloped downward toward the visual display terminal, tilted upward like a tent, or simply separated. These design features are intended to alleviate discomfort and possible musculoskeletal disorders that have been suggested to be associated with the extensive use of conventional computer keyboards. The geometry of conventional keyboards requires the wrists to be in 10 degrees to 15 degrees of ulnar deviation and 20 degrees of extension and the forearms to be nearly fully pronated while typing. A review of the available experimental data collected on 10-digit touch typists indicates that (1) keyboards with a slant angle (half of the opening angle) of 10 degrees to 12.5 degrees or keyboards with halves separated to approximately shoulder width are both effective in placing the wrist in near neutral (0 degree) ulnar/radial deviation when typing, (2) wrist extension can be reduced to near neutral (0 degrees) when a keyboard with a negative slope of 7.5 degrees is used, contingent on the wrist rest also sloping with the keyboard, and (3) tilting the keyboard halves 20 degrees to 30 degrees is effective in reducing forearm pronation to approximately 45 degrees. These studies also indicate that experienced 10-digit touch typists readily adapt (within 10 minutes) to these individual alternative keyboard features, and can type with approximately the same speed and accuracy as with the conventional keyboard. While placing the wrist and forearm in a more neutral position could, in theory, reduce the incidence of musculoskeletal disorders, randomized controlled trials are necessary before strong recommendations can be made on the effectiveness of alternative keyboards for the prevention and/or treatment of musculoskeletal disorders. In the absence of these randomized controlled trials, the information in this article provides preliminary guidance to clinicians in their evaluation of computer keyboards and workstations and their recommendations to patients.

Differences in measurements of lumbar curvature related to gender and low back pain.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To test the assumption that postural alignment and gender have a bearing on the specific type of low back pain (LBP) a person manifests. BACKGROUND: Measurements of static sagittal lumbar curvature are used by clinicians in the management of patients with LBP, but no investigator has reported differences in curvature related to specific categories of LBP. METHODS AND MEASURES: We used a computer-interfaced, 3-D, electromechanical digitizer to derive curvature angles for the region of the spine between T12-L1 and S2. Trained clinicians examined the subjects and determined their LBP diagnoses. We used t tests to examine differences in curvature between women and men, those with and those without LBP, and those in 4 different categories of LBP. We used chi2 to examine the relationship between gender and LBP category. RESULTS: Lumbar curvature angle (lordosis) was 13.2 degrees larger for women than for men (t = 6.74; P<.01). There was no difference in lumbar curvature between people with undifferentiated LBP and people without LBP. There were differences in lumbar curvature between people in various categories of LBP, for example, subjects in the lumbar-rotation-with-extension category had 8.4 degrees more lumbar curvature than subjects in the lumbar-rotation-with-flexion category (t = 2.16; P<.05). Based on the frequency distributions, there was a significant relationship between gender and LBP category (chi2 = 10.19; P<.01). CONCLUSIONS: Measurements of lumbar curvature should be expected to differ between men and women and may be related to different types of low back pain.

A field trial of the NASA Telemedicine Instrument Pack in a family practice.

BACKGROUND: Previous studies of telemedicine applications have demonstrated that the technology is effective but inefficient. Little attention has been directed to the primary care portion of the connection, especially the use of the medical peripheral devices. This study used a telemedicine testbed that simulates a rural practice environment to describe the effectiveness and efficiency of the NASA Telemedicine Instrument Pack, a small self-contained system of medical peripheral devices. METHOD: This study was an 8-week field trial of a suitcase-sized pack containing a fundus camera, flexible nasopharyngoscope, dermatology macrolens, light source, and video monitor. The pack was first studied in specialty clinics and then was used in a family practice office connected to the consultant node by digital lines. Evaluations were obtained from technicians, patients, and consultants. RESULTS: During 20 video clinic sessions, 59 patients with 38 different diagnoses were examined. The ear, nose, and throat portion of the exam was effective, with some decrement in color and clarity with compression of the signal. The eye portion was marginally effective, limited by a field of view that was too narrow and also by rigorous technician requirements. The skin exam was largely unacceptable primarily because the macrolens did not meet the requirements for color or clarity prior to compression of the signal. CONCLUSIONS: Subsequent design efforts for medical peripheral devices for telemedicine use will require significant modifications to "off the shelf" equipment to be effective and efficient. A family practice telemedicine testbed provides the appropriate environment for such field trials.

Left-handed versus right-handed computer mouse use: effect on upper-extremity posture.

Alternatives to reduce postural constraints have to be sought in order to reduce musculoskeletal complaints related to computer work. This study aimed at documenting the impact of using the mouse on the left side of a standard keyboard (with a right numeric keypad) on upper-extremity posture. A simulated computer task was performed by 27 subjects in a laboratory before and 1 month after ergonomics training. Shoulder flexion and abduction, as well as wrist extension were reduced with left-handed mouse use. Sixteen of the 27 subjects truly converted to using the mouse with the left hand. After a month of using the mouse with the left hand, the time required to perform the same task reduced, the perceived difficulty and discomfort improved, though the time to perform the task was still longer than when using the mouse with the right hand. For work involving both keyboard and mouse use, and without the need of the numeric keypad, it would probably be preferable to use a keyboard without the numeric keypad if the mouse is to be used on the right-hand side. If such keyboards are unavailable, an interesting alternative would be to use the mouse on the left side provided sufficient time is allowed to get accustomed to it.

Model-based testing with UML applied to a roaming algorithm for bluetooth devices.

In late 2001, the Object Management Group issued a Request for Proposal to develop a testing profile for UML 2.0. In June 2003, the work on the UML 2.0 Testing Profile was finally adopted by the OMG. Since March 2004, it has become an official standard of the OMG. The UML 2.0 Testing Profile provides support for UML based model-driven testing. This paper introduces a methodology on how to use the testing profile in order to modify and extend an existing UML design model for test issues. The application of the methodology will be explained by applying it to an existing UML Model for a Bluetooth device.

Effects of slanted ergonomic mice on task performance and subjective responses.

The biomechanical benefits (e.g., muscular activity) of slanted ergonomic mice have been comprehensively identified; however, their effects on task performance and subjective responses have not been fully investigated. The present study examined the effects of two slanted mice (slant angle = 30° and 50°) in comparison with a conventional mouse (slant angle = 0°) in terms of task performance (task completion time and error rate) and subjective responses (perceived discomfort score and overall satisfaction score). Experimental results showed that all of the task and subjective measures worsened as the slant angle of the target mice increases. For example, the task completion time (unit: ms) and overall satisfaction score (unit: point) of the 30° slanted mouse (time = 0.71, satisfaction = -0.09) and 50° slanted mouse (time = 0.73, satisfaction = -0.79) significantly deteriorated than the conventional mouse (time = 0.65, satisfaction = 1.21). The slanted mice seem to compromise biomechanical benefits with task performance and subjective responses.