Jennie J. Gallimore

A dual bin-packing approach to scheduling surgical cases at a publicly-funded hospital

Publicly-funded hospitals are typically allocated an annual budget by the government based on the number of enrollees in the region. Given tight budget constraints, the capacity of resources is fairly fixed. Such hospitals strive to maximize the utilization of their resources through continuous improvement and optimization techniques. We address a surgical case scheduling problem experienced at a publicly-funded hospital and conceptualize this multi-period, multi-resource, priority-based case scheduling problem as an unequal-sized, multi-bin, multi-dimensional dual bin-packing problem. A mixed integer programming model and a heuristic based on the first fit decreasing algorithm are presented. Resource availability, case priorities, and variation in surgery times are key features included in our model. Our proposed approach led to substantial savings, 20% reduction in number of days and up to 20% increase in operating room utilization, when compared to real schedules obtained from the surgical department at a publicly-funded hospital.

Visualization of 3‐D computer‐aided design objects

There are many significant human factors issues associated with the design and visualization of complex, computer‐generated images. One such issue is to determine the most effective techniques for providing engineers with realistic three‐dimensional (3‐D) objects. Differences in subjects’ ability to discriminate between the shape of two 3‐D, perspective, computer‐aided design‐type (CAD‐type) objects were investigated for various levels of monocular coding techniques and the binocular cue stereopsis. Performance was assessed at all combinations of five levels of monocular cues and two levels of disparity. The task was similar to the classic mental rotation paradigm except that subjects were provided with the ability to rotate one of the objects using a two‐dimensional (2‐D) joystick. Results indicate that interposition was the only depth cue that significantly enhanced subject performance. One explanation for the lack of significance of stereopsis is that, for this particular task, depth information provid...

Visualization of three-dimensional structure during computer-aided design

The visual image presented to an engineer using a computer‐aided design (CAD) system influences design activities such as decision making, problem solving, cognizance of complex relationships, and error correction. Because of the three‐dimensional (3‐D) nature of the object being created, an important attribute of the CAD visual interface concerns the various methods of presenting depth on the displays two‐dimensional (2‐D) surface. The objective of this research is to examine the effects of stereopsis on subjects’ ability to (a) accurately transfer to, and retrieve from, long‐term memory spatial information about 3‐D objects; and (b) visualize spatial characteristics in a quick and direct manner. Subjects were instructed to memorize the shape of a 3‐D object presented on a stereoscopic CRT during a study period. Following the study period, a series of static trial stimuli were shown. Each trial stimulus was rotated (relative to the original) about the vertical axis in one of six 36° increments between 0...

Display systems : design and applications

Partial table of contents: APPLICATIONS WHAT DRIVES THE REQUIREMENTS FOR DISPLAY? How Applications Have Driven Display Requirements (C. Machover) Display Requirements for Desktop Electronic Imaging (L. MacDonald) Estimation of the Visibility of Small Image Features on a VDU (D. Bosman) TECHNOLOGY WHAT CAN CURRENT DISPLAYS DELIVER? Matching Display Technology to the Application (A. Lowe) The Structure, Performance and Future of Passive Matrix LCDs (A. Mosley) Projection Systems (P. Candry) METROLOGY HOW CAN DISPLAY PERFORMANCE BE EVALUATED? Measurement and Standardisation in the Colorimetry of CRT Displays (A. Hanson) Evaluating Stereoscopic Displays for 3D Imagery (T. Bardsley & I. Sexton) Index.

Configural features of helmet-mounted displays to enhance pilot situation awareness

BACKGROUND In the current research, we used configural displays to investigate what design features contribute to the formation of operator situation awareness (SA). Configural displays have been shown to provide better performance for integration tasks, yet the design aspects of these displays which affect the formation of operator SA have not been determined. OBJECTIVE We compared the design features of three configural attitude head-up displays (HUD) [joint strike fighter (JSF), dual articulated (DA), and arc segment attitude reference (ASAR)] presented on a helmet mounted display (HMD) across four experiments to quantify what aspects of configural displays would affect pilot SA. METHODS In Experiment 1, nine expert pilots completed recall tasks for briefly-presented aircraft attitude displays to measure Level 1 SA performance. In Experiments 2-4, 10 highly trained pilots (expert group) and 10 flight test engineers (novice group) served as subjects to investigate higher level SA performance in an unusual attitude recovery (UAR) task. Experiments 3 and 4 included off-axis attitude symbology UARs. RESULTS Experiment 1 results indicated a higher percentage of correct responses for recognition of climb and dive states with the ASAR configural display. Results from Experiments 2-4 indicated no differences in performance. Results also showed that transitioning between dissimilar configural displays conveying attitude does not affect pilot SA. CONCLUSIONS This research discusses the specific properties of aviation configural displays. The results suggest that using these displays with the full range of aircraft states is sufficient for SA to be established when rapidly transitioning between dissimilar configural displays. Results indicate that differences in performance are diminished when using experts and significant training may overcome differences that exist among the configural displays.

THE EFFECTS OF FIELD-OF-VIEW ON PILOT HEAD MOVEMENT DURING LOW LEVEL FLIGHT

Helmet mounted displays are being considered for a variety of uses in military aviation including training, mission rehearsal, and as a primary flight display in the cockpit. There is a need for considerable research into issues related to the use of this technology and the effects on pilot performance, particularly with respect to spatial orientation. One critical issue is the field-of-view (FOV) necessary when flying military aircraft. The purpose of this research was to investigate the effects of FOV on pilot head movement. Head tilt, pitch, and yaw data were collected in a dome simulator during a low level VMC flight task under three FOV conditions (40, 60, and 100 degrees). Results indicated that pilots exhibited reflexive head tilt movements (Opto Kinetic Collic Reflex) regardless of FOV. Head pitch and yaw varied as a function of FOV. Pilots made significantly more downward pitch movements with the 40-degree FOV over a wider range of aircraft bank. Head yaw was more prevalent as FOV decreased.

Impact of Diabetes E-Consults on Outpatient Clinic Workflow:

Background. An e-consult is an electronic communication system between clinicians, usually a primary care physician (PCP) and a medical or surgical specialist, regarding general or patient-specific, low complexity questions that would not need an in-person consultation. The objectives of this study were to understand and quantify the impact of the e-consult initiative on outpatient clinic workflow and outcomes. Methods. We collected data from 5 different Veterans Affairs (VA) outpatient clinics and interviewed several physicians and staff members. We then developed a simulation model for a primary care team at an outpatient clinic. A detailed experimental study was conducted to determine the effects of factors, such as e-consult demand, view-alert notification arrivals, walk-in patient arrivals, and PCP unavailability, on e-consult cycle time. Results. Statistical tests indicated that 4 factors related to outpatient clinic workflow were significant, and levels within each of the 4 significant factors resulted in statistically different e-consult cycle times. The arrival rate of electronic notifications, along with patient walk-ins, had a considerable effect on cycle time. Splitting the workload of an unavailable PCP among the other PCPs, instead of the current practice of allocating it to a single PCP, increases the system’s ability to handle a much larger e-consult demand. Conclusions. The full potential of e-consults can only be realized if the workflow at the outpatient clinics is designed or modified to support this initiative. This study furthers our understanding of how e-consult systems can be analyzed and alternative workflows tested using statistical and simulation modeling to improve care delivery and outcomes.

Effectiveness of the C-sharp: reducing ergonomics problems at VDTs

The use of visual display terminals (VDTs) has been associated with complaints of visual fatigue and body discomfort. In an effort to eliminate some of these problems, an ergonomic emphasis has been placed on the design of computer workstations. A new device, the C-Sharp, has been developed to help reduce some of the ergonomics problems related to long-term VDT usage. The C-Sharp was designed to alleviate visual strain and temporary myopia by reducing the amount of muscular work associated with accommodation and convergence to near targets. It was also designed to eliminate glare. The present study is an ergonomics evaluation to determine whether the C-Sharp meets accepted standards and guidelines. Specifically, the objectives of the research are to determine the effects of the C-Sharp on operator reading and search performance, perceived comfort, body posture, and visual acuity. The C-Sharp is compared with mesh-glare filter and no-glare filter device conditions. Subjects were blocked into three groups based on age and type of vision correction (with or without bifocals). Results indicate that the C-Sharp meets the recommendations of the Americal National Standard for human factors engineering of visual display terminal workstations. No differences in objective performance were found between the three glare device conditions. The C-Sharp allowed bifocal wearers to keep their necks in natural postures rather than tilted backwards. Post-session far visual acuity worsened regardless of the device condition.

Interactive Model-Based Decision Making for Time-Critical Vehicle Routing

Advances in technology, software algorithms, and operations research methods provide the opportunity for effectively coupling the human decision maker with optimization modelling algorithms in large-scale systems operating in dynamic and uncertain environments. In military applications, such as search and rescue/destroy missions or real-time route planning or re-planning provide time windows within which critical decisions need to be made. Using a specially constructed human-computer integrated routing application, an evaluation was conducted to compare the effects of interactive model-based solutions with respect to automated solutions generated by mathematical modelling algorithms in the context of unmanned aerial vehicle route planning. Results indicate that significantly more high priority targets were covered in the human integrated approach compared to the automated solution without any significant degradation with respect to all the other dependent measures including percentage of total targets covered, low priority targets covered, total targets covered in threat zone, high priority targets covered in threat zone, and low priority targets covered in threat zone.

Expression of Personality through Avatars: Analysis of Effects of Gender and Race on Perceptions of Personality

Avatars and virtual agents are used in social, military, educational, medical, training, and other applications. Although there is a need to develop avatars with human-like characteristics, many applications include avatars based on stereotypes. Prabhala and Gallimore (2007) conducted research to develop collaborative computer agents with personality. Using the Big Five Factor Model of personality they investigated how people perceive personality based on actions, language, and behaviors of two voice-only computer agents in a simulation. However, these computer agents included no visual features in order to avoid stereotypes. The objective of the current research extends the work of Prabhala and Gallimore by investigating the effects of personality, race, and gender on perceived personality of avatars with animated faces. Results showed that subjects were able to distinguish the different personalities and race and gender significantly affected perceptions on a trait-by-trait basis.