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Distributed Maximum Power Point Tracking (DMPPT) concept provides effective anti-mismatch feature, however, it fails in extreme mismatch situation. To get full profit from PV system, quantitatively static analyzes of major DMPPT structures are presented. The existence criteria and quantitative evaluation method for optimal power region of different DMPPT structures are first proposed. Simulation and...
In this paper, a new wideband direction-of-arrival (DOA) estimation algorithm, which is an iterative coherent subspace method based on two-dimensional discrete Fourier transform (2D-DFT), is proposed. Two stages of focusing are accomplished in the algorithm. Firstly, a modified 2D-DFT, which has accomplished a preliminary focusing process, is exploited on the received data to achieve initial estimates...
In order to obtain the temperature distribution along inner helix of working TWTs, fiber Bragg grating array (FBGA) can be considered to be used in testing the temperature. Two testing methods based on FBGA embedded on/in support rod helix structure are proposed. The influence of the FBGA on beam-wave interaction is analyzed through CST. The results show that the structure with FBGA embedded in support...
In this paper, we review the file formats for data storage in radio astronomy. As a standard format used in astronomy, Flexible Image Transport System (FITS) is discussed firstly. Random Group FITS File (UVFITS) and FITS Interferometry Data Interchange (FITS-IDI) based on FITS are highlighted. And VOTable promoted by the development of Virtual Observatory (VO) is also briefly reviewed. We all know...
This paper addresses the power loss issue results from mismatch case which is critical to improving overall efficiency of the residential PV system. In general, a dedicated DC-DC converter with an extra distributed MPPT (Max Power Point Tracking) algorithm, what is called a MIMC (Module Integrated MPPT Converter), is connected to each panel to reduce the mismatch impact. However, even by adopting...
In this paper we propose a 2-2 pull-downed film mode detection and treatment method considering scrolling subtitles to improve the feathering problem of scrolling subtitles. The method includes: First, the screen is separated into two areas: subtitle area and other area. Second, film mode is detected in other area. Third, in the subtitle area, scrolling subtitles are searched. If it is 2-2 pull-downed...
Now high-capacity reversible watermarking has been a popular research topic in image watermarking. Existing algorithms only focus on the control of additional information, but ignore the process of original host image and watermark, so the embedding capacity is not fully utilized. In this paper, a high capacity reversible watermarking algorithm based on image segmentation and difference expansion...
High-density piezoelectric micromachined ultrasonic transducer (pMUT) arrays have been designed and fabricated using silicon based micromachined process. These devices are based on a novel structure called “reverse-bonding”. Experimental results show that they have excellent performance, suitable resonance frequency and high reliability. The fabricated pMUT arrays are very promising for 3-D medical...
This paper reports the performance of Block Diagonalization (BD) scheme for different array antenna structures used in a multiuser Multiple Input Multiple Output (MIMO) system. The assessment is performed in terms of sum rate capacity. Theoretical analysis as well as computer simulations shows that the spatial correlation downgrades downlink performance of BD. The simulations also reveal that the...
This paper reports investigations into mutual coupling effects on performance of a beamforming transmission scheme of a multiple-input multiple-output (MIMO) system operating under Rician channel conditions. It is shown that the presence of mutual coupling in a transmitting array antenna degrades the radiation pattern. However, it does not adversely affect the system capacity. If the correlated Rayleigh...
Piezoelectric micromachined ultrasonic transducer (pMUT) is a new approach to form high frequency arrays for real-time 3-D medical imaging. pMUT arrays based on SOI-Si bonding and PZT-coated membrane structures have been designed in this paper. After simulation, the 6×6 ultrasonic transducer array was fabricated and characterized. The total array area is approximately 2.0 mm by 2.0 mm. The micrograph...
This paper reports on the capacity of a MIMO system operating in a multi-access scenario. The investigations take into account co-channel interference as well as spatial correlation and mutual coupling (MC) present in array antennas. A closed-form expression for the upper bound of the mutual information is presented. An optimal signal transmission scheme is proposed to maximize the MIMO capacity....
Solving complex convection-diffusion equations is very important to many practical mathematical and physical problems. After the finite difference discretization, most of the time for equations solution is spent on sparse linear equation solvers. In this paper, our goal is to solve 2D Nonlinear Unsteady Convection-Diffusion Equations by accelerating an iterative algorithm named Jacobi-preconditioned...
The data structure diagram is abstracted from the diagram of railway yard signal arrangement. HBACA (hybrid behavior based ant colony algorithm) is presented to search the shortest route of railway yard. The route searching program based on HBACA is developed. The graphical representation of railway yard is given on the console. According to the designated beginning node and the designated ending...
The paper reports on the performances of training-based channel estimation methods in a multiple input multiple output (MIMO) communication system with transmitter equipped with a uniform linear array (ULA) and receiver equipped with either uniform circular array (UCA) or uniform linear array (ULA). In the undertaken investigations, the receiver is assumed to be free from any obstacles while the transmitter...
Finding all the occurrences of a twig query in an XML database is a core operation for efficient evaluation of XML queries. Since every complex twig query consists of linear ones, it is important to handle linear twig queries effectively. In this paper, we propose a novel path-partitioned encoding scheme, and find a holistic solution to match linear twig queries with no structural join. We show that...
Optical mark recognition (OMR) is a traditional data input technique and an important human computer interaction technique which is widely used in education testing. Aimed at the drawbacks of current OMR technique, a new image-based low cost OMR technique is presented in the paper. The new technique is capable of processing thin papers and low-printing precision answer sheets. The system key techniques...
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