261 research outputs found

    CRLB Based Optimal Noise Enhanced Parameter Estimation Using Quantized Observations

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    Cataloged from PDF version of article.In this letter, optimal additive noise is characterized for parameter estimation based on quantized observations. First, optimal probability distribution of noise that should be added to observations is formulated in terms of a Cramer–Rao lower bound (CRLB) minimization problem. Then, it is proven that optimal additive “noise” can be represented by a constant signal level, which means that randomization of additive signal levels is not needed for CRLB minimization. In addition, the results are extended to the cases in which there exists prior information about the unknown parameter and the aim is to minimize the Bayesian CRLB (BCRLB). Finally, a numerical example is presented to explain the theoretical results

    Grain yield and some physiological traits associated with heat tolerance in bread wheat (Triticum aestivum L.) genotypes

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    This research was carried out in the experimental fields of Department of Field Crops, Faculty of Agriculture, the University of Namık Kemal in 2014-2015. In the study, totally 30 bread wheat (Triticum aestivum L.) genotypes (15 cultivars; early, medium-early and late-maturing 10 lines are tolerant to the heat-temperature stress which were provided by CIMMYT-International Maize and Wheat Improvement Center), 5 lines (were taken from the same university’s wheat breeding program which was collaborated by the CIMMYT) were used as an experimental material. The experiment was adjusted in a split-plot design with 3 replicates. Sowing dates (Normal (NS ? November 09, 2014) and Late sowing (LS ? January 09, 2015)) were constituted the main plots, and the genotypes constituted the sub-plots. These physiological traits ((membrane thermostability (MT), canopy temperature (CT), leaf chlorophyll content (LCC) and stomatal conductance (SC)) were measured at the LS stage due to giving much more correct, logical and meaningful results, but grain yield (GY) was fixed for all the sowing dates. Obtained findings are: The GY was varied between (4.35- 6.34 t ha-1) for genotypes; the MT was changed between (10.58-66.25%); the CT was realized between (17.67-22.00 oC); the LCC was varied between (38.30-53.30 SPAD) and the SC was changed between (25.20-166.80 mmol m-2 s-1). It was observed that most of the CIMMYT originated genotypes are tolerant to high-temperature stress and most of the wheats that are grown in Thrace Region are negatively affected by the high-temperature stress. © Ankara Üniversitesi Ziraat Fakültesi.AR.14.15This work was supported by the Office of Scientific Research Projects of Tekirda? Nam?k Kemal University (Project No. NKUBAP.00.24.AR.14.15).This work was supported by the Office of Scientific Research Projects of Tekirdağ Namık Kemal University (Project No. NKUBAP.00.24.AR.14.15)

    High carrier concentration induced effects on the bowing parameter and the temperature dependence of the band gap of Ga<sub>x</sub>In<sub>1−x</sub>N

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    The influence of intrinsic carrier concentration on the compositional and temperature dependence of the bandgap of GaxIn1-xN is investigated in nominally undoped samples with Ga fractions of x = 0.019, 0.062, 0.324, 0.52, and 0.56. Hall Effect results show that the free carrier density has a very weak temperature dependence and increases about a factor of 4, when the Ga composition increases from x = 0.019 to 0.56. The photoluminescence (PL) peak energy has also weak temperature dependence shifting to higher energies and the PL line shape becomes increasingly asymmetrical and broadens with increasing Ga composition. The observed characteristics of the PL spectra are explained in terms of the transitions from free electron to localized tail states and the high electron density induced many-body effects. The bowing parameter of GaxIn1-xN is obtained from the raw PL data as 2.5 eV. However, when the high carrier density induced effects are taken into account, it increases by about 14% to 2.9 eV. Furthermore, the temperature dependence of the PL peak becomes more pronounced and follows the expected temperature dependence of the bandgap variation

    Programmer's Manual for XMTC Language, XMTC Compiler and XMT Simulator

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    Explicit Multi-Threading (XMT) is a computing framework developed at the University of Maryland as part of a PRAM-on-chip vision (http://www.umiacs.umd.edu/users/vishkin/XMT). Much in the same way that performance programming of standard computers relies on C language, XMT performance programming is done using an extension of C called XMTC. This manual presents the second generation of XMTC programming paradigm. It is intended to be used by an application programmer, who is new to XMTC. In the first part of this technical report (UMIACS-TR 2005-45 Part 1 of 2), we define and describe key concepts, list the limitations and restrictions, and give examples. The second part (UMIACS-TR 2005-45 Part 2 of 2) is a brief tutorial, and it demonstrates the basic programming concepts of XMTC language with examples and exercises

    Information support and interactive planning in the digital factory : approach and industry-driven evaluation

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    In the modern world we are continuously surrounded by information. The human brain has to analyse and interpret this information to transform into useable knowledge that is then used in decision making activities. The advent and implementation of Industry 4.0 will make it a requirement for systems within factories to interact and share large quantities of information with each other. This large volume of information will make it even more difficult for the human resources within the factory to sift through the large amount of information required since there is a limit to the information that our brains can cope with. Just in time information retrieval (JITIR) within the digital factory environment aims to provide support to the human stakeholders in the system by proactively yet non-intrusively providing the required information at the right time based on the users context. This paper will therefore provide an insight into the cognitive difficulties experienced by humans in the digital factory and how JITIR can tackle these challenges. By validating the JITIR concept, several industry scenarios have been evaluated: an exemplary model, concerning the machine tool industry, is presented in the paper. The results of this research are a set of guidelines for the development of a digital factory support tool.peer-reviewe

    ARBITRATE-AND-MOVE PRIMITIVES FOR HIGH THROUGHPUT ON-CHIP INTERCONNECTION NETWORKS

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    An n-leaf pipelined balanced binary tree is used for arbitration of order and movement of data from n input ports to one output port. A novel arbitrate-and-move primitive circuit for every node of the tree, which is based on a concept of reduced synchrony that benefits from attractive features of both asynchronous and synchronous designs, is presented. The design objective of the pipelined binary tree is to provide a key building block in a high-throughput mesh-of-trees interconnection network for Explicit Multi Threading (XMT) architecture, a recently introduced parallel computation framework. The proposed reduced synchrony circuit was compared with asynchronous and synchronous designs of arbitrate-and-move primitives. Simulations with 0.18m technology show that compared to an asynchronous design, the proposed reduced synchrony implementation achieves a higher throughput, up to 2 Giga- Requests per second on an 8-leaf binary tree. Our circuit also consumes less power than the synchronous design, and requires less silicon area than both the synchronous and asynchronous designs

    Cocaine- and amphetamine-regulated transcript promoter regulated by nicotine in nerve growth factor-treated PC12 cells

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    Nicotine and cocaine- and amphetamine-regulated transcripts (CART) have several overlapping functions, such as the regulation of reward, feeding behavior, stress response, and anxiety. Previous studies showed that nicotine regulates CART expression in various brain regions. However, the molecular mechanisms underlying this regulation are not known. This study investigated the regulatory effect of nicotine on promoter activity of the CART gene in PC12 cells, which were differentiated into a neuronal phenotype by nerve growth factor (NGF) treatment. Two vectors containing reporter genes (Gaussia luciferase or mCherry) and the 1,140-bp upstream of the transcriptional start site of the mouse CART gene are used to analyze the CART promoter activity. Transient transfection of PC12 cells with either vector displayed strong promoter activity in both undifferentiated and differentiated PC12 cells. CART promoter activity in the PC12 cell line is increased by forskolin or NGF treatment. In differentiated PC12 cells, exposure to 50 nM nicotine for 6 h increased CART promoter activity. However, treatment with higher nicotine doses for 6 h and treatment with all nicotine doses for 24 h showed no effect. A nicotine concentration of 50 nM is comparable to brain nicotine levels experienced by chronic smokers over long periods of time. Taken together, these data indicate that nicotine may exert some of its actions through the regulation of CART transcription in the brain

    Overshoot mechanism in transient excitation of THz and Gunn oscillations in wide-bandgap semiconductors

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    A detailed study of high-field transient and direct-current (DC) transport in GaN-based Gunn diode oscillators is carried out using the commercial simulator Sentaurus Device. Applicability of drift-diffusion (DD) and hydrodynamic (HD) models to high-speed, highfrequency devices is discussed in depth, and the results of the simulations from these models are compared. It is shown, for a highly homogeneous device based on a short (2 μm) supercritically doped (1017 cm-3) GaN specimen, that the DD model is unable to correctly take into account some essential physical effects which determine the operation mode of the device. At the same time, the HD model is ideally suited to solve such problems due to its ability to incorporate non-local effects. We show that the velocity overshoot near the device contacts and space charge injection and extraction play a crucial role in defining the operation mode of highly homogeneous short diodes in both the transient regime and the voltagecontrolled oscillation regime. The transient conduction current responses are fundamentally different in the DD and HD models. The DD current simply repeats the velocity-field (v-F) characteristics, and the sample remains in a completely homogeneous state. In the HD model, the transient current pulse with a full width at half maximum of approximately 0.2 ps is increased about twofold due to the carrier injection (extraction) into (from) the active region and the velocity overshoot. The electron gas is characterized by highly inhomogeneous distributions of the carrier density, the electric field and the electron temperature. The simulation of the DC steady states of the diodes also shows very different results for the two models. The HD model shows the trapped stable anodic domain in the device, while the DD model completely retains all features of the v-F characteristics in a homogeneous gas. Simulation of the voltage-controlled oscillator shows that it operates in the accumulation layer mode generating microwave signals at 0.3 to 0.7 THz. In spite of the fact that the known criterion of a Gunn domain mode n0L > (n0L)0 was satisfied, no Gunn domains were observed. The explanation of this phenomenon is given. © 2012 Momox et al
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