We discuss the many factors affecting the reliability of GaAs HBTs that we have encountered starting from the early days of AlGaAs-emitter HBTs through the present day use of InGaP-emitter HBTs. We discuss both wearout and infancy failure modes and try to distinguish fundamental (i.e., unavoidable) from nonfundamental failure modes. We have found that infant failures are dominated by substrate dislocation density, which can limit long-term-reliable circuit sizes to under ~1000 transistors.
This paper presents a light-weight process for 3D reconstruction and measurement of chronic wounds using a commonly available smartphone as an image capturing device. The first stage of our measurement pipeline comprises the creation of a dense 3D point cloud using structure-from-motion (SfM). Furthermore, the wound area is segmented from the surrounding skin using dynamic thresholding in CIELAB color space and a surface is estimated to simulate the missing skin in the wound area. Together with a mesh reconstruction of the wound, the skin surface and the segmented wound is used to calculate the wound dimensions, i.e., its length, surface area and volume. We evaluate the presented pipeline using three wound phantoms, representing different stages in healing, and compare the subsequently scanned and measured wound dimensions with manually measured ones.
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