Design-build experiences and student-centered-learning in biomedical engineering curricula

ABSTRACT The field of biomedical engineering (BME) is progressing rapidly into new areas, demanding the BME students to develop multidisciplinary skills, knowledge and a possibility for life-long learning. Changing the educational arena from teacher-centered to studentcentered-learning is a challenge in the BME domain. CDIO (Conceive Design Implement Operate) design-build courses, starting at the freshman year, makes laboratory and research environment enhance student-centered-learning resulting in communicative skills and teamwork. BME specialization, student-centered-learning and design-build experiences are introduced as an integrative part during the third and fourth academic year. Student-centeredlearning is often recognized as a situation where the learning possibilities are relevant to the students and where the students themselves determine the short-term goals. The expert or authority teaching has to be replaced by mentorship and facilitators. This is recognized in design-build courses. BME cases without a known solution can be treated and solved through integrative thinking and problem identification. The cognitive tasks require the acquisition and synthesis of information. It prepares students to participate in research laboratories as undergraduates and it prepares them for time-constrained problem-solving in the real world. For research studies and developments in working life, skills including dynamic group processes and awareness of the affective domain are necessary. BME education has three years experience of design-build courses from the freshman to the last academic year. Directives for the projects are based on clinical settings or demands engaging students to solve real world problems. Interaction with real customers or experts in the field encourages, stimulate and enhance all parts of the CDIO framework. To get a prosperous and successful work throughout the project cycle the project teams as we believe should be built on heterogeneous skill, age and gender, the affective domain all harmonized using a team contract. Project groups have also been enrolled with exchange students creating international groups. Feedback of the group process is given throughout the design-build project but especially after completion. Theoretical parts supplement the project and the group both in-depth but also to focus and harmonize the group towards the designbuild project outcome. Experts working in the field validate and test the project. Assessment is conformant to a student-centered-learning process as an integrative part of the course. Development of assessment protocols and strategies as an integrative part of the learning process must be stimulated and emphasized

From Point Measurements to Imaging

of television, of time clocks, of traffic on the freeway, but few are observers. Everyone is looking, not many are seeing.

In Vivo Diffuse Reflectance Spectroscopy of Human Tissue : From Point Measurements to Imaging

This thesis presents the non-invasive use of diffuse reflectance spectroscopy (DRS) to provide information about the biochemical composition of living tissue. During DRS measurements, the incident, visible light is partially absorbed by chromophores but also scattered in the tissue before being remitted. Human skin and heart, the main tissue objects in this thesis, are dependent on a sufficient inflow of oxygenized blood, and outflow of metabolic byproducts. This process could be monitored by DRS using the spectral fingerprints of the most important tissue chromophores, oxyhemoglobin and deoxyhemoglobin. The Beer-Lambert law was used to produce models for the DRS and has thus been a foundation for the analyses throughout this work. Decomposition into the different chromophores was performed using least square fitting and tabulated data for chromophore absorptivity. These techniques were used to study skin tissue erythema induced by a provocation of an applied heat load on EMLA-treated skin. The absorbance differences, attributed to changes in the hemoglobin concentrations, were examined and found to be related to, foremost, an increase in oxyhemoglobin. To estimate UV-induced border zones between provoked and nonprovoked tissue a modified Beer-Lambert model, approximating the scattering effects, was used. An increase of chromophore content of more than two standard deviations above mean indicated responsive tissue. The analysis revealed an edge with a rather diffuse border, contradictory to the irradiation pattern. Measuring in the operating theater, on the heart, it was necessary to calculate absolute chromophore values in order to assess the state of the myocardium. Therefore, a light transport model accounting for the optical properties, and a calibrated probe, was adopted and used. The absolute values and fractions of the chromophores could then be compared between sites and individuals, despite any difference of the optical properties in the tissue. A hyperspectral imaging system was developed to visualize the spatial distribution of chromophores related to UV-provocations. A modified Beer-Lambert approximation was used including the chromophores and a baseline as an approximate scattering effect. The increase in chromophore content was estimated and evaluated over 336 hours. In conclusion, advancing from a restricted Beer-Lambert model, into a model estimating the tissue optical properties, chromophore estimation algorithms have been refined progressively. This has allowed advancement from relative chromophore analysis to absolute values, enabling precise comparisons and good prediction of physiological conditions

Estimate the age of a tree stand and site index using aerial footage

Hållbart skogsbruk kräver kunskap om skogens tillstånd i nutid samt tänkbara framtida åtgärder. Syftet med studien var att undersöka om det via digitala flygbilder var möjligt att skatta trädålder och SI på beståndsnivå, samt med vilken precision det kan utföras.Endast tall- och/ eller grandominerade bestånd, valdes i Vetlanda och Nybro kommun. Flygbilderna bearbetades av Foran Sverige AB med hjälp av ett program framtaget av Spacemetric AB.De fältinventerade beståndens data jämfördes med medianvärden från de skattade trädhöjderna, vilka matades in i en formel, konstruerad för att göra en kurvanpassning mot de nya höjdutvecklingskurvorna.Metoden för framtagning av höjdvärden via bildmatchning bör förfinas, t.ex. bör laserskanningen bidra med högre precision. Endast mindre delar av landet har mer än en skanningstidpunkt med laser, metoden kräver minst två höjdvärden i serie.Syftet med studien anses uppfyllt, dock hade studien tjänat på en bättre metod för att sålla bort felaktiga data innan analys. Generaliserbarheten är god på liknande bestånd, vidare studier krävs för att kunna påvisa en användarbarhet i olika typer av bestånd, där även olika skötselvarianter bör vägas in