915 research outputs found

    A two-step multiuser detection scheme for space-time coded MIMO OFDM systems

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    In this paper, we investigate transceiver design for a wideband multiuser-multiple-input, multiple-output (MIMO) communication system, where the co-channel users are equipped with multiple transmit and multiple receive antennas. In particular, we develop a two-step hard-decision interference cancellation receiver for a multiuser-MIMO uplink system which employs orthogonal frequency division multiplexing (OFDM) modulation and space-time block codes (STBC). The STBC has been implemented either over adjacent tones or adjacent OFDM symbols and the performances of both implementations have been tested under slowly time-varying channels. The two-step receiver structure has been implemented using a combined interference suppression scheme based on minimum mean-squared error (MMSE) and symbol-wise likelihood detectors, which is then followed by an interference cancellation step. The receiver can suppress and cancel the interference from the co-channel users effectively without increasing the complexity significantly. The paper also includes computer experiments that are intended to improve the understanding of specific issues involved in the design of multiuser STBC-OFDM systems

    Kata Ganti Orang Dalam Bahasa Inggris Dan Bahasa Selaru (Suatu Analisis Kontrastif)

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    This research attempts to identify and classify personal pronouns in English and Selaru language. The data are taken from interviewing some informants (native speakers) who was born in Selaru and understand the language and can interact effectively. The identified data are analyzed according to the concept of Bloomfield and then contrast them by using Lado\u27s concept. In analyzing the data, the writer uses descriptive method. The problems of this research ore focused on what are the personal pronouns in terms of form and function in English and Selaru language and what are the similarities and differences of personal pronouns in terms of form and function in English and Selaru language. The aims of the research are to identify and classify personal pronouns in English and Selaru language and to find out the similarities as well as dissimilarities of personal pronouns in both languages in terms of form and function. The results of this research shows that English and Selaru language has similarities and dissimilarities. Similarities in English and Selaru language which has the form of the first person, second, third, both singular and plural and dissimilarities in English and Selaru language namely: in English has object, possessive pronoun and third person singular neutral,whereas in selaru language not found

    Spatial distribution of surround suppression of a sample recording site.

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    <p>Surround suppression was not always uniform for the firing rate (A) and gLFP (B). In this recording site, both responses had a distinct LSR of similar sizes. These LSRs did not overlap, but were aligned to the optimal direction. The dashed circle indicates the SSF size and position. The dashed arrow indicates the optimal direction of firing rate, which was also the drifting direction of all stimuli. For the sake of illustration, the data were interpolated four times by a 2D third-order spline.</p

    Size-tuning responses of a sample recording site.

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    <p>(A–C) Multi-unit and LFP responses to the enlarging drifting gratings. Black vertical lines indicate the stimulus onset and offset times. The gray horizontal bars indicate the sustained response windows. (D) Size-tuning curve of the sustained response of mean firing rate. The data points indicate the mean ± SE. The solid line is the DoG function fitted from the data, with Adjust-R<sup>2</sup> = 0.951. The dashed line indicates the response level of uniform background control. (E) LFP power spectrum of different stimulus sizes. The gray bar indicates gamma band. (F) Normalized spike power spectrum of different stimulus sizes. The color code is identical to that of (E). (G) Size-tuning curve of sustained gLFP. The Adjust-R<sup>2</sup> of the fitted DoG was 0.871. The legends are identical to those of (D).</p

    Association between intrauterine mild hyperglycemia and post-natal high-fat diet with adiponectin and AMPK pathway genes

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    <p>To investigate the mechanisms of maternal–fetal interactions in the setting of gestational diabetes mellitus. We investigated the long-term effects of intrauterine mild hyperglycemia and a postnatal high-fat diet on the glucose metabolism of adult offspring, and explored the role of adiponectin on hepatic gluconeogenesis. Twenty-one pregnant Wistar rats were randomly divided into an intrauterine hyperglycemia group (group D, <i>n</i> = 14) and a control group (group C, <i>n</i> = 7). Offspring were divided into four groups according to intrauterine blood glucose level and post-weaning dietary patterns (high-fat diet groups: DF and CF or normal diet groups: DN and CN, <i>n</i> = 8 per group). The average birth weights of group D offspring were higher than for group C. In the DF rats, low adiponectin mRNA expression in perirenal and epididymal fat was significantly positively correlated with low hepatic AdipoR1 mRNA expression and significantly correlated with high hepatic PEPCK, G-6-Pase, and PGC-1α mRNA levels. In DF rats, hepatic P-AMPK was cytoplasmically located and its level was decreased; in these rats, hepatic CRTC2 was expressed in the nucleus and its level was significantly increased. Our study shows that the dietary structure of offspring has a large influence on the incidence of abnormal glucose tolerance.</p
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