Browsing by Subject "Usability testing"

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    Patient-Specific Rib Cage and Thoracic Volume Reconstruction in Spine Patients Using Biplanar Radiographs
    (2019-06) Lee, Po-Chih
    Spine deformity problems are common among different age cohorts. Progressive deformities of the spine deform the rib cage and cause complications, like cardiopulmonary disorders, back pain or mortality. A severe spine deformity has a negative influence on patients’ pulmonary function, because the limited thoracic cavity restricts the lungs from fully expanding. To evaluate spine patients’ respiratory function, doctors may use pulmonary function tests or CT scans to measure the lung volume. Since the former highly rely on patients’ understanding of the test instructions, the test results might be inaccurate when the instructions are not followed properly. The latter are often criticized for the high-dose radiation, and frequent exposure to CT scans adds risk to patients. In this study, the thoracic volume serves as an alternative way to follow up spine patients’ lung volume, and a simulation method to reconstruct the rib cage and measure the thoracic volume using biplanar X-rays is proposed. The semi-automatic software is designed based on this simulation method. Usability testing is conducted to evaluate the performance of the developed software. Also, a comparison of the thoracic volume measurements between my method and other existing methods is made. Two case studies are carried out to show the thoracic volume measured by the developed software can be a surrogate for the prediction of the lung function in spine patients. One case study is to monitor the thoracic volume variation during the growing rod surgical treatments in pediatric scoliosis patients, and the benefit of the growing rod surgery is discussed. The other is to correlate the parameters obtained from pulmonary function tests with the thoracic volume in adult scoliosis patients having different treatments during their adolescence. With the developed software, two quantitative studies are performed via virtual spine patients with osteoporotic or Scheuermann’s kyphosis vertebral wedging deformities. The influence of the wedging location and numbers on thoracic volume changes is explored. A replicable simulation workflow to create virtual spine patients is proposed, and its application in future clinical settings is also discussed.
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    Web Site usability: a case study of student perceptions of educational web sites.
    (2010-05) Ballard, Joyce Kimberly
    As distance education has moved from traditional correspondence courses to online educational web sites, it becomes important to look at the usability or "ease of use" of instructional web sites from the student's perspective. The nonlinear, hypertext format of the Web can pose various problems for learners as they attempt to complete course-related tasks. Any difficulties that students have using this technology will compound and increase their cognitive load above and beyond learning the course content. Although many articles and books have been published about web-based learning, only limited empirical research has emerged to inform the development and design of educational course sites. This research explored what the construct of usability means for students taking online courses from the perspective of 74 students enrolled in an online and distance learning program. Six courses, matched on subject matter, were selected for study. These courses were designed and developed by two different groups, professional and nonprofessional developers. Starting with an expert heuristic evaluation of the course sites, this study used both quantitative and qualitative measures to record the experiences of students enrolled in these six courses and determine how students judge the usability of educational web sites. Based on the analysis of the study variables according to course development type, the results of this study found that Nielsen's usability heuristics (a respected evaluation tool used primarily to measure the usability of commercial web sites) can be used to evaluate instructional web sites and used to differentiate between levels of usability in the same way that usability is judged by students.