677 research outputs found

    TOPOLOGICALLY MINIMAL REALIZATION OF A NEGATIVE RESISTOR USING NULLORS AND POSITIVE RESISTORS

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    Although it is heuristically well-known that a negative resistor can be realized with nullors and positive resistors, the minimal realization of it have not been discussed systematically in detail. In this paper, based upon the general fundamental properties of linear active networks, it is proved systematically that nullors not less than one (two) and positive resistors not less than three ( one, respectively ) are necessary to realize a negative resistor and there exist only two circuits for the topologically minimal realization disregarding the labelling of nullors and resistors

    An Algorithm for the Set of All Generators of an Arbitrary Firing Count Vector in Petri Nets

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    In this paper, an effective method to obtain all nonnegative integer minimal support vectors (U4,V4) at level 4 for an arbitrary homogeneous / inhomogeneous solution of a matrix equation A x = b (A∈Zmxn, b∈Zmxl) starting from nonnegative rational number minimal support vectors (U3,V3) at level 3 is proposed. Although V4 has been derived from all minimal vectors (U5,V5) of level 5 which are obtained starting from vectors at levell, 2, or 3, so far, this proposed method for (U4,V4) gives us a big shortcut comparing with them. However, it is pointed out that obtaining (U5,V5) of level 5 from (U4,V4) of level 4 is difficult

    Low-Complexity Strategies for Multiple Access Relaying

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    In this paper, we propose three low-complexity strategies for Multiple Access Relay Channel (MARC) based on the concept of bit-flipping model. By estimating the error rates of the links between the sources and the relay, and by utilizing the estimate as side information at the destination, it is shown that the proposed relay strategies are superior to the Decode-and-Forward (DF) relay strategy when all links are suffering from Additive White Gaussian Noise (AWGN). Furthermore, extrinsic information transfer (EXIT) analysis is used to track the convergence property with the aim of being able to search for suitable codes, the proposed relay strategies can achieve the performance close to those strategies utilizing relatively strong codes, such as turbo code or LDPC code, with iterative decoding at the relay in order to make intra links error free

    A case of lung abscess successfully treated by transbronchial drainage using a guide sheath

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    A 51-year-old man was diagnosed with colon cancer in September 2011, and a solitary pulmonary nodule was detected by computed tomography (CT) scan. We performed a transbronchial biopsy with endobronchial ultrasonography using a guide sheath (GS) and diagnosed lung metastasis of colon cancer. The patient experienced remittent fever after the biopsy in spite of intravenous antibiotic therapies. Moreover, his CT scan showed a large lung abscess at the biopsy site. We performed transbronchial drainage using a GS as salvage therapy. The bloody pus was successfully aspirated, and chest X-ray following the procedure showed dramatic shrinkage of the abscess
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