2,019 research outputs found

    Less is More: Micro-expression Recognition from Video using Apex Frame

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    Despite recent interest and advances in facial micro-expression research, there is still plenty room for improvement in terms of micro-expression recognition. Conventional feature extraction approaches for micro-expression video consider either the whole video sequence or a part of it, for representation. However, with the high-speed video capture of micro-expressions (100-200 fps), are all frames necessary to provide a sufficiently meaningful representation? Is the luxury of data a bane to accurate recognition? A novel proposition is presented in this paper, whereby we utilize only two images per video: the apex frame and the onset frame. The apex frame of a video contains the highest intensity of expression changes among all frames, while the onset is the perfect choice of a reference frame with neutral expression. A new feature extractor, Bi-Weighted Oriented Optical Flow (Bi-WOOF) is proposed to encode essential expressiveness of the apex frame. We evaluated the proposed method on five micro-expression databases: CAS(ME)2^2, CASME II, SMIC-HS, SMIC-NIR and SMIC-VIS. Our experiments lend credence to our hypothesis, with our proposed technique achieving a state-of-the-art F1-score recognition performance of 61% and 62% in the high frame rate CASME II and SMIC-HS databases respectively.Comment: 14 pages double-column, author affiliations updated, acknowledgment of grant support adde

    Shockley-Ramo theorem and long-range photocurrent response in gapless materials

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    Scanning photocurrent maps of gapless materials, such as graphene, often exhibit complex patterns of hot spots positioned far from current-collecting contacts. We develop a general framework that helps to explain the unusual features of the observed patterns, such as the directional effect and the global character of photoresponse. We show that such a response is captured by a simple Shockley-Ramo-type approach. We examine specific examples and show that the photoresponse patterns can serve as a powerful tool to extract information about symmetry breaking, inhomogeneity, chirality, and other local characteristics of the system.Comment: 7 pgs, 3 fg

    Unification of bulk and interface electroresistive switching in oxide systems

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    We demonstrate that the physical mechanism behind electroresistive switching in oxide Schottky systems is electroformation, as in insulating oxides. Negative resistance shown by the hysteretic current-voltage curves proves that impact ionization is at the origin of the switching. Analyses of the capacitance-voltage and conductance-voltage curves through a simple model show that an atomic rearrangement is involved in the process. Switching in these systems is a bulk effect, not strictly confined at the interface but at the charge space region.Comment: 4 pages, 3 figures, accepted in PR

    Further investigation of a contactless patient-electrode interface of an Electrical Impedance Mammography system

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    The Sussex Mk4 Electrical Impedance Mammography (EIM) system is a novel instrument, designed for the detection of early breast cancer, based upon Electrical Impedance Tomography (EIT). Many innovations in the field have been incorporated in the design improving both signal distribution and response. This paper investigates the behaviour of the contactless patient-electrode interface. The interface was studied in detail using phantom and healthy volunteer, in-vivo, data. Our findings show the necessity for the careful design of electrode enclosure so that the response of the system is not affected by the unpredictable positioning of the breast; it closely mimics those conditions seen when using the phantom. The paper includes a number of possible designs and their individual characteristics. In addition an explanation on the unanticipated effects and solutions for such are described. © 2010 IOP Publishing Ltd

    Deep Basement Construction Through an Existing Basemement at the Central Business District of Hong Kong

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    In June 2002, a 32-storey high quality commercial building with a 3-level deep basement, namely Chater House, was completed. The Chater House site was previously occupied by the Swire House and its basement structure and foundations obstructed the construction of the new basement. Temporary pipe pile walls with grout curtain were used to facilitate local trimming/demolition of the existing basement slab and pile caps. Diaphragm walls were constructed through the locally demolished basement to retain the soils for the 15m deep excavation and the new basement was constructed by top-down construction method. In addition, the diaphragm walls and large diameter bored piles were constructed to support the vertical loads and wind shear from the superstructure. This paper describes the geotechnical design aspects of the new development. The difficulties and special issues during the substructure construction works are also discussed. Instrumentation monitoring results are also reviewed and compared with the predicted movements

    A planar Al-Si Schottky Barrier MOSFET operated at cryogenic temperatures

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    Schottky Barrier (SB)-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a novel device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.Comment: 6 pages, 4 figures, minor changes from the previous version

    The Use of Medicinal Mushroom or Herb as Effective Immunomodulatory Agent

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    Background: Medicinal mushrooms are mushrooms used with the aim for health enhancement. They have been used in traditional Chinese medicine (TCM) for thousands of years. These mushrooms and some herbal medicines have gain in popularity in recent times, largely due to a growing number of scientific studies that suggest their potential medical benefits. They are found to exert immunomodulatory effects through changes in the quantity of some specific cytokines in blood; as well as numbers and activities of distinct immune cell subsets. This article summarizes the immunomodulatory effects of two commonly consumed medicinal mushrooms (Coriolus versicolor and Ganoderma lucidum) and also three herbal medicines that have been categorized as immunomodulatory in function (Cordyceps sinensis, Astragalus membranaceus and Eleutherococcus senticosus). Methods: A systematic search of published articles of clinical trial studies between 1985 and August 2015 was conducted in four electronic databases (EMBASE, PubMed, Scopus and Web of Science). The outcome measures included changes in the serum cytokines secretion and the number and functional activity of different immune cell populations. Results: After a thorough literature searching of 237 relevant articles, 15 were included. Coriolus versicolor and Ganoderma lucidum showed immunomodulatory effects in both innate and adaptive immunity arms. There are only very few studies in each mushroom or herb, and unequivocal conclusions cannot be drawn. Future larger trials of randomized and placebo controlled clinical studies with laboratory investigation of changes of multiple immune populations and their subsets are needed in consistent with an evidence-based medicine approach
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