Hidden Markov models for gesture recognition

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 41-42).by Donald O. Tanguay, Jr.M.Eng

Novel liquid chromatography–mass spectrometry method shows that vitamin E deficiency depletes arachidonic and docosahexaenoic acids in zebrafish (Danio rerio) embryos

To test the hypothesis that embryogenesis depends upon α-tocopherol (E) to protect embryo polyunsaturated fatty acids (PUFAs) from lipid peroxidation, new methodologies were applied to measure α-tocopherol and fatty acids in extracts from saponified zebrafish embryos. A solid phase extraction method was developed to separate the analyte classes, using a mixed mode cartridge (reverse phase, π–π bonding, strong anion exchange), then α-tocopherol and cholesterol were measured using standard techniques, while the fatty acids were quantitated using a novel, reverse phase liquid chromatography–mass spectrometry (LC–MS) approach. We also determined if α-tocopherol status alters embryonic lipid peroxidation products by analyzing 24 different oxidized products of arachidonic or docosahexaenoic (DHA) acids in embryos using LC with hybrid quadrupole-time of flight MS. Adult zebrafish were fed E- or E+ diets for 4 months, and then were spawned to obtain E- and E+ embryos. Between 24 and 72 hours post-fertilization (hpf), arachidonic acid decreased 3-times faster in E- (21 pg/h) compared with E+ embryos (7 pg/h, P<0.0001), while both α-tocopherol and DHA concentrations decreased only in E- embryos. At 36 hpf, E- embryos contained double the 5-hydroxy-eicosatetraenoic acids and 7-hydroxy-DHA concentrations, while other hydroxy-lipids remained unchanged. Vitamin E deficiency during embryogenesis depleted DHA and arachidonic acid, and increased hydroxy-fatty acids derived from these PUFA, suggesting that α-tocopherol is necessary to protect these critical fatty acids.KEYWORDS: Embryogenesis, Neurogenesis, Hybrid quadrupole-time of flight MS, Arachidonic acid, Vitamin EThis is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Elsevier. The published article can be found at: http://www.journals.elsevier.com/redox-biolog

Compile-time Loop Splitting for Distributed Memory Multiprocessors

In a distributed memory multiprocessor, a program's task is partitioned among the processors to exploit parallelism, and the data are partitioned to increase referential locality. Though the purpose of partitioning is to shorten the execution time of an algorithm, each data reference can become a complex expression based upon the data partitions. As an attempt to minimize the computation needed for array references, loop splitting can further divide a partitioned loop into segments that allow the code hoisting and strength reduction optimizations. This thesis introduces two methods of loop splitting, rational and interval. While rational splitting divides the loop into equal-length GCD segments, interval splitting specifies segments as an explicit list of intervals. These two methods have been implemented and studied. Under our execution model, the loop in the algorithms analyzed executes an average of 2 to 3 times faster after loop splitting

ACHIEVING HIGH-RESOLUTION VIDEO USING SCALABLE CAPTURE, PROCESSING, AND DISPLAY

Abstract: New video applications are becoming possible with the advent of several enabling technologies: multicamera capture, increased PC bus bandwidth, multicore processors, and advanced graphics cards. We present a commercially-available multicamera system and a software architecture that, coupled with industry trends, create a situation in which video capture, processing, and display are all increasingly scalable in the number of video streams. Leveraging this end-to-end scalability, we introduce a novel method of generating high-resolution, panoramic video. While traditional point-based mosaicking requires significant image overlap, we gain significant advantage by calibrating using shared observations of lines to constrain the placement of images. Two non-overlapping cameras do not share any scene points; however, seeing different parts of the same line does constrain their spatial alignment. Using lines allows us to reduce overlap in the source images, thereby maximizing final mosaic resolution. We show results of synthesizing a 6 megapixel video camera from 18 smaller cameras, all on a single PC and at 30 Hz.

Understanding Performance in Coliseum, an

Coliseum is a multiuser immersive remote teleconferencing system designed to provide collaborative workers the experience of face-to-face meetings from their desktops. Five cameras are attached to each PC display and directed at the participant. From these video streams, view synthesis methods produce arbitrary-perspective renderings of the participant and transmit them to others at interactive rates, currently about 15 frames per second. Combining these renderings in a shared synthetic environment gives the appearance of having all participants interacting in a common space. In this way, Coliseum enables users to share a virtual world, with acquired-image renderings of their appearance replacing the synthetic representations provided by more conventional avatar-populated virtual worlds. The system supports virtual mobility—participants may move around the shared space—and reciprocal gaze, and has been demonstrated in collaborative sessions of up to ten Coliseum workstations, and sessions spanning two continents. Coliseum is a complex software system which pushes commodity computing resources to the limit. We set out to measure the different aspects of resource, network, CPU, memory, and disk usage to uncover the bottlenecks and guide enhancement and control of system performance. Latency is a key component of Quality of Experience for video conferencing. We present how each aspect of the system—cameras, image processing, networking, and display—contributes to total latency. Performance measurement is as complex as the system to which it is applied. We describe several techniques to estimate performance through direct light-weight instrumentation as well as use of realistic end-to-end measures that mimic actual user experience. We describe the various techniques and how they can be used to improve system performance for Coliseum and other network applications