scholarly journals Three-Dimensional Extensions of Resolvability of Two Point Targets in MIMO Radar Using a Hypothesis Test Formulation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ning Zhang ◽  
Jun Tang ◽  
Shuang Wan ◽  
Wei Zhu
Keyword(s):  
Hypothesis Test ◽  
Three Dimensional ◽  
Doppler Frequency ◽  
Mimo Radar ◽  
Broadband Noise ◽  
Closed Form Expression ◽  
Ratio Test ◽  
Three Dimension ◽  
Resolution Limit ◽  
Direction Of Departure

Multiple-input multiple-output (MIMO) radar has been extensively studied in recent years, due to its outstanding performance in various aspects. Resolution and estimation of the targets’ parameters are central capabilities of a MIMO radar system. In this paper, the resolution performance of MIMO radar in terms of the three-dimensional statistical resolution limit (3D SRL) is investigated, where three-dimension refers to direction of arrival (DOA), direction of departure (DOD), and Doppler frequency of a target. The scenario of two closely spaced targets corrupted by broadband noise with/without clutter sources is considered and the closed-form expression of the resolution threshold, which is the minimum signal-to-noise ratio (SNR) required for a given resolution performance, is derived using a generalized likelihood ratio test (GLRT) formulation. Finally, both theoretical and numerical analyses are provided for some insights regarding the resolution limit.

scholarly journals Statistical Angular Resolution Limit for Ultrawideband MIMO Noise Radar

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Xiaoli Zhou ◽  
Hongqiang Wang ◽  
Yongqiang Cheng ◽  
Yuliang Qin ◽  
Haowen Chen
Keyword(s):  
Angular Resolution ◽  
Signal To Noise Ratio ◽  
Mimo Radar ◽  
Optimization Criterion ◽  
Ratio Test ◽  
Theoretic Approach ◽  
Resolution Limit ◽  
Factors Affecting ◽  
Noise Radar ◽  
The Relationship

The two-dimensional angular resolution limit (ARL) of elevation and azimuth for MIMO radar with ultrawideband (UWB) noise waveforms is investigated using statistical resolution theory. First, the signal model of monostatic UWB MIMO noise radar is established in a 3D reference frame. Then, the statistical angular resolution limits (SARLs) of two closely spaced targets are derived using the detection-theoretic and estimation-theoretic approaches, respectively. The detection-theoretic approach is based on the generalized likelihood ratio test (GLRT) with given probabilities of false alarm and detection, while the estimation-theoretic approach is based on Smith’s criterion which involves the Cramér-Rao lower bound (CRLB). Furthermore, the relationship between the two approaches is presented, and the factors affecting the SARL, that is, detection parameters, transmit waveforms, array geometry, signal-to-noise ratio (SNR), and parameters of target (i.e., radar cross section (RCS) and direction), are analyzed. Compared with the conventional radar resolution theory defined by the ambiguity function, the SARL reflects the practical resolution ability of radar and can provide an optimization criterion for radar system design.

scholarly journals Angle Estimation for MIMO Radar in the Presence of Gain-Phase Errors with One Instrumental Tx/Rx Sensor: A Theoretical and Numerical Study

2021 ◽  
Vol 13 (15) ◽  
pp. 2964
Author(s):  
Fangqing Wen ◽  
Junpeng Shi ◽  
Xinhai Wang ◽  
Lin Wang
Keyword(s):  
Numerical Study ◽  
Multiple Input Multiple Output ◽  
Mimo Radar ◽  
Phase Errors ◽  
Direction Of Departure ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Angle Pair ◽  
Parallel Factor ◽  
Parafac Decomposition

Ideal transmitting and receiving (Tx/Rx) array response is always desirable in multiple-input multiple-output (MIMO) radar. In practice, nevertheless, Tx/Rx arrays may be susceptible to unknown gain-phase errors (GPE) and yield seriously decreased positioning accuracy. This paper focuses on the direction-of-departure (DOD) and direction-of-arrival (DOA) problem in bistatic MIMO radar with unknown gain-phase errors (GPE). A novel parallel factor (PARAFAC) estimator is proposed. The factor matrices containing DOD and DOA are firstly obtained via PARAFAC decomposition. One DOD-DOA pair estimation is then accomplished from the spectrum searching. Thereafter, the remainder DOD and DOA are achieved by the least squares technique with the previous estimated angle pair. The proposed estimator is analyzed in detail. It only requires one instrumental Tx/Rx sensor, and it outperforms the state-of-the-art algorithms. Numerical simulations verify the theoretical advantages.

Three Dimensional Detection of the via in the PCB CT Image Using Morphology Operation

2015 ◽  
Vol 752-753 ◽  
pp. 1406-1412
Author(s):  
Lei Zeng ◽  
Jian Chen ◽  
Han Ning Li ◽  
Bin Yan ◽  
Yi Fu Xu ◽  
...  
Keyword(s):  
Nondestructive Testing ◽  
Printed Circuit Board ◽  
Three Dimensional ◽  
Detection Algorithm ◽  
Circuit Board ◽  
Dimensional Structure ◽  
Three Dimension ◽  
Shape Information ◽  
Printed Circuit ◽  
Testing Technology

In modern industry, the nondestructive testing of printed circuit board (PCB) can prevent effectively the system failure and is becoming more and more important. As a vital part of the PCB, the via connects the devices, the components and the wires and plays a very important role for the connection of the circuits. With the development of testing technology, the nondestructive testing of the via extends from two dimension to three dimension in recent years. This paper proposes a three dimensional detection algorithm using morphology method to test the via. The proposed algorithm takes full advantage of the three dimensional structure and shape information of the via. We have used the proposed method to detect via from PCB images with different size and quality, and found the detection performances to be very encouraging.

Generation Mechanism of Broadband Whoosh Noise in an Automotive Turbocharger Centrifugal Compressor

2021 ◽  
pp. 1-35
Author(s):  
Rick Dehner ◽  
Pranav Sriganesh ◽  
Ahmet Selamet ◽  
Keith Miazgowicz
Keyword(s):  
Centrifugal Compressor ◽  
Combustion Engine ◽  
Three Dimensional ◽  
Leading Edge ◽  
Broadband Noise ◽  
Rotor Blades ◽  
Generation Mechanism ◽  
Primary Concern ◽  
Frequency Range ◽  
Modal Decomposition

Abstract The present study focuses on the acoustics of a turbocharger centrifugal compressor from a spark-ignition internal combustion engine. Whoosh noise is typically the primary concern for this type of compressor, which is loosely characterized by broadband sound elevation in the 4 to 13 kHz range. To identify the generation mechanism of broadband whoosh noise, the present study combines three approaches: three-dimensional (3D) computational fluid dynamics (CFD) predictions, experiments, and modal decomposition of 3D CFD results. After establishing the accuracy of predictions, flow structures and time-resolved pressures are closely examined in the vicinity of the main blade leading edge. This reveals the presence of rotating instabilities that may interact with the rotor blades to generate noise. An azimuthal modal decomposition is performed on the predicted pressure field to determine the number of cells and the frequency content of these rotating instabilities. The strength of the rotating instabilities and the frequency range in which noise is generated as a consequence of the rotor-rotating instability interaction, is found to correspond well with the qualitative trend of the whoosh noise that is measured several duct diameters upstream of the rotor blades. The variation of whoosh frequency range between low and high rotational speeds is interpreted through this analysis. It is also found that the whoosh noise primarily propagates along the duct as acoustic azimuthal modes. Hence, the inlet duct diameter, which governs the cut-off frequency for multi-dimensional acoustic modes, determines the lower frequency bound of the broadband noise.

Three Dimensional Bacteria Concentration by Negative Dielectrophoresis

2013 ◽  
Vol 699 ◽  
pp. 251-256
Author(s):  
T. Hisajima ◽  
L. Mao ◽  
K. Shinzato ◽  
M. Nakano ◽  
J. Suehiro
Keyword(s):  
Escherichia Coli ◽  
Numerical Simulation ◽  
Dielectric Layer ◽  
Parallel Plate ◽  
Three Dimensional ◽  
Three Dimension ◽  
Escherichia Coli Cells ◽  
Opposite Electrode ◽  
Novel Method ◽  
Thin Dielectric Layer

Thispaper reports a novel method to concentrate bacteria in three-dimension by negative dielectrophoretic (n-DEP) force in a microchannel. This was achieved by placing a thin dielectric layer on one of a pair of parallel plate electrodes. The dielectric layer having a home-plate like pentagonal shape, forms a gradient of electric field causing n-DEP. A three-dimensional numerical simulation of bacteria trajectory predicts that bacteria flowing a microchannel were three-dimensionally concentrated beneath the tip of the pentagonal dielectric thin layer. The trajectory and concentration of bacteria under n-DEP force were also experimentally confirmed using Escherichia coli cells. Bacteria moved along edges of the dielectric layer and were pushed to the opposite electrode, resulting in their concentration in three-dimension. The proposed device might be applicable to selective concentration of bacteria depending on their dielectric properties.

scholarly journals Based on systems science methodology—— Research on the talent training system of hall three-dimensional structure

2020 ◽  
Vol 198 ◽  
pp. 01050
Author(s):  
Yong-Chen ◽  
Zhong Hua-Cheng ◽  
Qi-Xu
Keyword(s):  
Three Dimensional ◽  
Training System ◽  
Three Dimensions ◽  
Structure Theory ◽  
Dimensional Structure ◽  
Systems Science ◽  
Three Dimension ◽  
Time Dimension ◽  
Dimension Analysis ◽  
Science Methodology

Draw lessons from the basic idea of system science methodology, based on the hall three dimensions structure theory construction of research personnel training problems, from the time dimension, logic knowledge and three dimension analysis of all aspects of talent cultivation system, clear the talent training theory support, and solve the problem of a series of contradictions in the process of talent training, further enriched and developed the theoretical system of talents cultivation.

The Research and Practice of Three-Dimensional Innovation Talents Development Model in Engineering Education

2012 ◽  
Vol 591-593 ◽  
pp. 2286-2289
Author(s):  
Xiu Qin Wu ◽  
Tie Liang Liu ◽  
Zhian Yi
Keyword(s):  
Engineering Education ◽  
Teaching Method ◽  
Three Dimensional ◽  
Training Model ◽  
Development Model ◽  
Three Dimension ◽  
Self Study ◽  
Long Time ◽  
Innovation Study ◽  
Develop Environment

Cultivating students who have innovated abilities is not only an age requirement but also the focus of engineering education. In engineering education, according to the studies and practices for a very long time, this article establish "three-dimension" innovation talents development model which can improve students’ abilities of self-study and help them fit the society better after their graduation. The seven aspects are teaching method, learning approach, teaching material constructs, auxiliary answering strategy, teaching evaluation, students develop environment and innovation channels. “Three-dimensional” innovation talents development model is designed according to students’ character and their best innovation study result .And it can actually form a three-dimensional layered training model includes “General-form Teaching”, “Extensions Expand” and “Elites Cultivating”. The effect of the practice of "three-dimensional" innovation talents development model is very obvious.

The Role of Three Dimension Computerized Imaging in Hand Surgery

1987 ◽  
Vol 12 (3) ◽  
pp. 349-352
Author(s):  
J. ENGEL ◽  
M. SALAI ◽  
B. YAFFE ◽  
R. TADMOR
Keyword(s):  
Three Dimensional ◽  
Hand Surgery ◽  
New Technique ◽  
Silicone Implants ◽  
Three Dimension ◽  
Two Dimensional ◽  
Radiological Imaging ◽  
Preliminary Results ◽  
Dimensional Picture

Three-dimensional computerized imaging is a new modality of radiological imaging. This new technique transforms the two-dimensional slices of bi-plane CT into a three-dimensional picture by a computer’s monitor adjusted to the system. This system enables the physician to rotate the angle of viewing of the desired region to any desired angle. Moreover, this system can delete certain features of different densities from the picture, such as silicone implants, thus improving visualization. Our preliminary results using this technique are presented. The advantages, pitfalls, and suggested future applications of this new technique in hand surgery are discussed.

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