R. Darin Ellis

Modeling computer interest in older adults: the role of age, education, computer knowledge, and computer anxiety.

We proposed a mediation model to examine the effects of age, education, computer knowledge, and computer anxiety on computer interest in older adults. We hypothesized that computer knowledge and computer anxiety would fully mediate the effects of age and education on computer interest. A sample of 330 older adults from local senior-citizen apartment buildings completed a survey that included an assessment of the constructs included in the model. Using structural equation modeling, we found that the results supported the hypothesized mediation model. In particular, the effect of computer knowledge operated on computer interest through computer anxiety. The effect of age was not fully mitigated by the other model variables, indicating the need for future research that identifies and models other correlates of age and computer interest. The most immediate application of this research is the finding that a simple 3-item instrument can be used to assess computer interest in older populations. This will help professionals plan and implement computer services in public-access settings for older adults. An additional application of this research is the information it provides for training program designers.

Increasing the Usability of Online Information for Older Users: A Case Study in Participatory Design

This article describes one of the first documented participatory design (PD) efforts specifically aimed at older users. The goal of the project was to make an existing World Wide Web (WWW) site more user-friendly for older users, specifically in terms of display format issues. A PD team was assembled from a group of community-dwelling older adults and developers from a university research lab. After the developers established the trust and confidence of the participants and developed a conceptual user model (based on a survey and previous literature), the PD team evaluated the original design. Prototypes were iteratively developed and tested by the PD team to improve problems found in the original design. Specific design improvements and general design guidelines for older WWW users are discussed.

NASA TLX: Software for assessing subjective mental workload

The NASA Task Load Index (TLX) is a popular technique for measuring subjective mental workload. It relies on a multidimensional construct to derive an overall workload score based on a weighted average of ratings on six subscales: mental demand, physical demand, temporal demand, performance, effort, and frustration level. A program for implementing a computerized version of the NASA TLX is described. The software version assists in simplifying collection, postprocessing, and storage of raw data. The program collects raw data from the subject and calculates the weighted (or unweighted) workload score, which is output to a text file. The program can also be tailored to a specific experiment using a simple input text file, if desired. The program was designed in Visual Studio 2005 and is capable of running on a Pocket PC with Windows CE or on a PC with Windows 2000 or higher. The NASA TLX program is available for free download.

The Utility of Display Space in Keeping Track of Rapidly Changing Information

The results of 4 experiments suggest that the information available in graphic displays can have considerable performance consequences and that the kind of display invariants provided can interact with variables such as task difficulty, working-memory load, and the organization of information that is to be remembered. In Experiment 1, participants benefited from the presence of invariant spatial correlates of values to be remembered and showed superior performance (fewer errors and faster responses) relative to participants using a spatially impoverished display, regardless of information organization. Experiment 2 showed that the presence of unique verbal labels for items to be remembered aids keeping track performance. Experiments 3 and 4 provided further evidence that participants kept track of changing information best in conditions with spatial display invariants. These data are relevant to practitioners faced with designing soft monitoring displays - that is, displays involving multiple attributes of a single object in some cases (e.g., the temperature and pressure in a boiler) and one attribute of many objects in others (e.g., the current flow through several valves feeding the same system). Actual or potential applications of this research include improving computer displays designed to support complex, memoryintensive monitoring performance

Communication Strategies and Timeliness of Response to Life Critical Telemetry Alarms

BACKGROUND A centralized electrocardiogram telemetry monitoring system (TMS) facilitates early identification of critical arrhythmias and acute medical decompensation. Timely intervention can only be performed if abnormalities are communicated rapidly to the direct caregiver. The study objectives were to measure effectiveness of bi-directional voice communication badges versus one-way alphanumeric pagers for telemetry alarm response and communication loop closure. METHODS A sequential observational pilot study of nursing response to TMS alarms compared communication technologies on four nursing units in a 1,061 bed tertiary care hospital with 264 TMS channels of telemetry over a 2-year period. Subsequently, the communication technologies were compared in a randomized fashion on a 68-bed progressive cardiac care unit. Caregivers were blinded to the protocol. All alarm responses were recorded during two periods using either pagers or voice communication devices. Alarm response time and closure of the communication loop were analyzed in a blinded fashion. RESULTS The direct communication functionality of the badge significantly shortened the time to first contact, time to completion, and rate of closure of the communication loop in both the pilot and study phases. Median time to first contact with the communication badge was 0.5  min, compared to 1.6  min with pager communication (p < 0.0003). Communication loop closure was achieved in 100% of clinical alarms using the badge versus 19% with the pager (p < 0.0001). CONCLUSIONS Communication badge technology reduced alarm time to first contact and completion as well as facilitated communication loop closures. Immediate two-way communication significantly impacted practice, alarm management, and resulted in faster bedside care.

Ontology-based modeling and integration of morphological characteristics of assembly joints for network-based collaborative assembly design

Abstract This paper presents our research on developing an ontology-based framework that can represent morphological characteristics related to assembly joints. Joints within the physical structure of an assembly are inevitable because of the limitations of component geometries and the associated, required engineering properties. Consequently, a framework is needed that can capture and propagate assembly design and joint information in a robust assembly model throughout the entire product development processes. The framework and model are based on an understanding of the morphological characteristics of an assembly and its different physical effects. The morphological characteristics are consequences of the principal physical processes and of the design intentions. Therefore, the morphological characteristics should be carefully represented while considering the geometry and topology of assembly joints. In this research, assembly joint topology is defined by a mereotopology, which is a region-based theory for the parts and associated concepts. This formal ontology can differentiate often ambiguous assembly and joining relations. Furthermore, the mereotopological definitions for assembly joints are implemented in Semantic Web Rule Language (SWRL) rules and Web Ontology Language triples. This process provides universality to the mereotopological definitions. Two geometrically and topologically similar joint pairs are presented to describe how the assembly joints can be defined in mereotopology and be transformed into SWRL rules. Web3D is also employed to support network-enabled sharing of assembly geometry. Finally, the proposed modeling framework is demonstrated using a real fixture assembly. This case study demonstrates the usability of the proposed framework for network-based design collaboration.

Listener: A tool for client-side investigation of hypermedia navigation behavior

Behavioral researchers have employed hypermedia-based software applications in their experiments for some time. More recently, interest in the World-Wide Web has developed among researchers in the social sciences, and popular use of this new medium continues to grow at an incredible rate. This paper describes Listener, a tool developed to log users’ hypermedia and World-Wide Web navigation behavior using Apple Macintosh computers in a laboratory setting. Listener is able to capture navigation actions through cached documents, overcoming some of the problems associated with analyzing standard web server logs.

Soft Boundary Approach for Unsupervised Gesture Segmentation in Robotic-Assisted Surgery

Robotic-assisted surgery holds significant promise to improve patient treatment by allowing surgeons to perform many types of complex operations with greater precision and flexibility than before. In order to facilitate automation of robotic surgery and more practical training for surgeons, more detailed comprehension of the surgical procedures is needed. In this regard, a key step is to develop techniques that segment and recognize surgical tasks intelligently. Surgeries involve complex continuous activities that may contain superfluous, repeated actions, and temporal variation. Therefore, any segmentation approach that has the capability to account for all these characteristics is of increased interest. Toward this goal, we develop a new segmentation algorithm, namely soft-boundary unsupervised gesture segmentation (Soft-UGS), to segment the temporal sequence of surgical gestures and model gradual transitions between them using fuzzy membership scores. The proposed framework is evaluated using a real robotic surgery dataset. Our extensive set of experiments and evaluation metrics show that the proposed Soft-UGS method is able to match manual annotations with upto 83% sensitivity, 81% precision, and 73% segmentation score. The results show that the proposed soft boundary approach can provide more insight into the surgical activities and can contribute to the automation of robotic surgeries.

Usability and Accessibility Comparison of Governmental, Organizational, Educational and Commercial Aging/Health-Related Web Sites

This study is aimed at answering whether aging/health-related web sites of different domain extensions (i.e. .com, .edu, .gov and .org) differ in their accessibility and usability, and whether these two measures are correlated. The usability and accessibility of governmental, organizational, educational and commercial aging/health-related web sites were compared using two automatic evaluation tools: Bobby and LIFT. The governmental web site group has the highest compliance with Web site Content Accessibility Guide although only 52% got an approved status. The accessibility approval was found to correlate significantly with overall usability ratings for all groups, except the commercial web site group.

Performance of basic manipulation and intracorporeal suturing tasks in a robotic surgical system: single- versus dual-monitor views

BackgroundTechnical advances in the application of laparoscopic and robotic surgical systems have improved platform usability. The authors hypothesized that using two monitors instead of one would lead to faster performance with fewer errors.MethodsAll tasks were performed using a surgical robot in a training box. One of the monitors was a standard camera with two preset zoom levels (zoomed in and zoomed out, single-monitor condition). The second monitor provided a static panoramic view of the whole surgical field. The standard camera was static at the zoomed-in level for the dual-monitor condition of the study. The study had two groups of participants: 4 surgeons proficient in both robotic and advanced laparoscopic skills and 10 lay persons (nonsurgeons) who were given adequate time to train and familiarize themselves with the equipment. Running a 50-cm rope was the basic task. Advanced tasks included running a suture through predetermined points and intracorporeal knot tying with 3–0 silk. Trial completion times and errors, categorized into three groups (orientation, precision, and task), were recorded.ResultsThe trial completion times for all the tasks, basic and advanced, in the two groups were not significantly different. Fewer orientation errors occurred in the nonsurgeon group during knot tying (p = 0.03) and in both groups during suturing (p = 0.0002) in the dual-monitor arm of the study. Differences in precision and task error were not significant.ConclusionsUsing two camera views helps both surgeons and lay persons perform complex tasks with fewer errors. These results may be due to better awareness of the surgical field with regard to the location of the instruments, leading to better field orientation. This display setup has potential for use in complex minimally invasive surgeries such as esophagectomy and gastric bypass. This technique also would be applicable to open microsurgery.