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 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 Detection Performance Analysis of the Standard FDA and FDA-MIMO Radar in the Gaussian Background

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yongze Liu ◽  
Yuehong Ma ◽  
Haiming Jing
Keyword(s):  
Array Signal Processing ◽  
Signal To Noise Ratio ◽  
Mimo Radar ◽  
Detection Performance ◽  
Ratio Test ◽  
Test Statistics ◽  
Test Statistic ◽  
Processing Scheme ◽  
Radar Systems ◽  
Frequency Diverse Array

This paper studies the optimal detection performance of the standard frequency diverse array (FDA) radar and FDA multi-input multioutput (FDA-MIMO) radar in Gaussian clutter and noise. Array signal processing scheme at the receiver is firstly designed to obtain the array steering vector containing range, azimuth, and frequency increment. For the two array configurations, namely, collocated transmit-receive and collocated transmit distributed receive, the likelihood ratio test statistics and the test statistic distributions are derived in the Neyman–Pearson sense. It is then investigated how the number of array elements influences the detection performance of various radar systems at low signal-to-noise ratio (SNR). Several numerical simulations are carried out to demonstrate that the performance improvement is hard for MIMO and FDA-MIMO by only increasing the number of transmit elements, while it is achievable for the FDA. The paper finally makes a comparative analysis for detection performances of five radar configurations under different SNRs.

The number of employed as a macroeconomic indicator of working time dynamics

2020 ◽  
Vol 16 (5) ◽  
pp. 935-945
Author(s):  
I.A. Zaikova
Keyword(s):  
Comparative Analysis ◽  
Manufacturing Sector ◽  
Working Hours ◽  
Working Time ◽  
Labor Costs ◽  
Factors Affecting ◽  
Time Dynamics ◽  
Developed Economies ◽  
The Relationship ◽  
Macroeconomic Indicator

Subject. The working time of workers at any stage of economic development is a value reflecting the level of labor productivity. Any progress in productivity contributes to changes in the volume of labor costs and the number of employed. Depending on the relationship between the total volume of labor costs and the number of employed, the duration of working time per one worker may change (it may increase, decrease, or remain unchanged). Objectives. The study aims to confirm the importance of such a macroeconomic indicator as the number of employed in varying working hours. Methods. The study rests on the comparative analysis of countries with developed economies based on some indicators like dynamics of the working time fund, dynamics of the number of employed, average number of hours worked during the year per employee, etc. The analyzed timespan is 25 years (from 1991 to 2016). Results. The comparative analysis revealed that in the non-production sphere and the economy as a whole the macroeconomic determinants correlate so that the length of working time per worker reduces. When considering the analysis results for the manufacturing sector, no single trend was identified. Conclusions. One of the key factors affecting the change in working hours is the number of employed. The relationship between the working time fund and the number of employed directly determines the dynamics of working time per worker.

scholarly journals The Mediating Effect of Marital Intimacy on the Relationship between Spouse-Related Stress and Prenatal Depression in Pregnant Couples: An Actor–Partner Interdependent Model Test

2021 ◽  
Vol 18 (2) ◽  
pp. 487
Author(s):  
Miyoung Lee ◽  
Yeon-Suk Kim ◽  
Mi-Kyoung Lee
Keyword(s):  
Mediating Effect ◽  
Prenatal Depression ◽  
Mediating Effects ◽  
Factors Affecting ◽  
Marital Intimacy ◽  
Paternal Factors ◽  
Two Cities ◽  
Related Stress ◽  
The Relationship ◽  
Structured Questionnaire

Prenatal depression is an important factor in predicting postpartum depression. Most studies have assessed factors affecting prenatal depression by focusing on pregnant wives. However, the emotional and psychological aspects of both expectant parents need to be considered. Therefore, the purpose of this study was to examine the effect of spouse-related stress in expectant couples on prenatal depression and investigate the mediating effects of marital intimacy on this relationship. A total of 120 expectant couples from two cities in Korea at more than 15 weeks of completed pregnancy participated in the study. Using a structured questionnaire, we assessed the general characteristics of the participants, spouse-related stress, prenatal depression, and marital intimacy. The results revealed that four actor effects and one partner effect were significant. Marital intimacy and prenatal depression among expectant parents were affected by spouse-related stress. Moreover, spouse-related stress in the husbands completely mediated marital intimacy in pregnant wives, demonstrating partner effects on prenatal depression in pregnant wives. Therefore, it was observed that paternal factors affect prenatal depression in pregnant wives. This warrants the inclusion of husbands in marital interventions and strategies to improve marital intimacy in pregnant wives.

scholarly journals Comparison of the sensitivity of Western blotting between PVDF and NC membranes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yufang Xiang ◽  
Yuanyuan Zheng ◽  
Shaobo Liu ◽  
Gang Liu ◽  
Zhi Li ◽  
...  
Keyword(s):  
Western Blotting ◽  
Polyvinylidene Fluoride ◽  
Staining Intensity ◽  
Detection Sensitivity ◽  
Key Factors ◽  
Post Translational Modifications ◽  
Factors Affecting ◽  
Molecular Weights ◽  
Direct Blue ◽  
The Relationship

AbstractWestern blotting (WB) is one of the most widely used techniques to identify proteins as well as post translational modifications of proteins. The selection of electroblotted membrane is one of the key factors affecting the detection sensitivity of the protein which is transferred from gel to membrane in WB. The most common used membranes are polyvinylidene fluoride (PVDF) and nitrocellulose (NC) membranes. Which membrane of these two is more suitable for WB has not been reported so far. Here, by incubating proteins which were transferred to PVDF or NC membranes with a series of antibodies and different types of lectins, we investigated the relationship between the binding ability of these two membranes to proteins or glycoproteins and the molecular weight of the target protein. The antibody re-probed ability of the two membranes was also explored. Moreover, we verified the above results by directly incubating proteins having different molecular weights onto PVDF or NC membranes. Bound proteins were stained with direct blue-71, and the staining intensity was quantitated by scanning and densitometry.

scholarly journals The Influence of Pre-Procedural Imaging and Cystic Duct Cholangiography on Endoscopic Transpapillary Gallbladder Drainage in Acute Cholecystitis

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1286
Author(s):  
Junya Sato ◽  
Kazunari Nakahara ◽  
Yosuke Michikawa ◽  
Ryo Morita ◽  
Keigo Suetani ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Acute Cholecystitis ◽  
Cystic Duct ◽  
Magnetic Resonance Cholangiopancreatography ◽  
Procedure Time ◽  
Technical Success ◽  
Factors Affecting ◽  
Gallbladder Drainage ◽  
Procedural Evaluation ◽  
The Relationship

Endoscopic transpapillary gallbladder drainage (ETGBD) for acute cholecystitis is challenging. We evaluated the influence of pre-procedural imaging and cystic duct cholangiography on ETGBD. Patients who underwent ETGBD for acute cholecystitis were retrospectively examined. The rate of gallbladder contrast on cholangiography, the accuracy of cystic duct direction and location by computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP), and the relationship between pre-procedural imaging and the technical success of ETGBD were investigated. A total of 145 patients were enrolled in this study. Gallbladder contrast on cholangiography was observed in 29 patients. The accuracy of cystic duct direction and location (proximal or distal, right or left, and cranial or caudal) by CT were, respectively, 79%, 60%, and 58% by CT and 68%, 55%, and 58% by MRCP. Patients showing gallbladder contrast on cholangiography underwent ETGBD with a significantly shorter procedure time and a lower rate of cystic duct injury. No other factors affecting procedure time, technical success, and cystic duct injury were identified. Pre-procedural evaluation of cystic duct direction and location by CT or MRCP was difficult in patients with acute cholecystitis. Patients who showed gallbladder contrast on cholangiography showed a shorter procedure time and a lower rate of cystic duct injury.

scholarly journals Stimulation of mitochondrial calcium ion efflux by thiol-specific reagents and by thyroxine. The relationship to adenosine diphosphate retention and to mitochondrial permeability

1979 ◽  
Vol 182 (2) ◽  
pp. 455-464 ◽  
Author(s):  
E J Harris ◽  
M Al-Shaikhaly ◽  
H Baum
Keyword(s):  
Thyroid Hormones ◽  
Calcium Ion ◽  
Adenine Nucleotides ◽  
Adenosine Diphosphate ◽  
Ruthenium Red ◽  
Reduced Form ◽  
Factors Affecting ◽  
Ph Values ◽  
Rat Heart Mitochondria ◽  
The Relationship

Respiring rat heart mitochondria were loaded with Ca2+ and then treated with Ruthenium Red. The factors affecting the subsequent Ca2+-efflux were studied. Addition of rotenone or antimycin led to a decline of efflux except at pH values above 7.2, provided the load was less than about 80 nmol per mg of protein. Oligomycin reversed the effect of the respiratory inhibitors. Independently of respiration, efflux was stimulated by the uncoupler trifluoromethyltetrachlorbenzimadazole, by mersalyl and by thyroid hormones. The stimulated efflux could be diminished by ADP, with Mg2+ as cofactor if efflux was rapid. With respiration in progress, efflux could be stimulated by N-ethylmaleimide and 5,5′-dithiobis-(2-nitrobenzoate). The effects of mersalyl and of thyroid hormones could be diminished with dithiothreitol. In the absence of stimulating agents, the Ca2+ efflux was proportional to the load up to some critical amount, this critical amount was decreased by the agents. Thyroxine and mersalyl caused not only loss of Ca2+, but also simultaneous, but not necessarily proportional, loss of internal adenine nucleotides. Both efflux rates were kept at a low value by bongkrekic acid added before the stimulating agent. It is concluded that Ca2+ efflux is a measure of a permeability controlled by the binding of ADP (an Mg2+) to the inner membrane, and that this in turn depends on the maintenance of certain thiol gropus in a reduced form by a reaction that uses NADH and ATP and the energy-linked transhydrogenase.

scholarly journals Environmental factors affecting the wintering raptor community in Armenia, Southern Caucasus

2021 ◽  
Author(s):  
Gianpasquale Chiatante ◽  
Michele Panuccio
Keyword(s):  
General Pattern ◽  
Abundant Species ◽  
Theoretic Approach ◽  
Factors Affecting ◽  
Milvus Migrans ◽  
Gyps Fulvus ◽  
Black Kite ◽  
Southern Caucasus ◽  
And Migration ◽  
Information Theoretic Approach

AbstractThe species–habitat relationships can change during the year because of the seasonality of resources. Therefore, the investigation of habitat use by animals in each season plays a fundamental role in their conservation. The main aim of this research was to investigate the raptor community that spends the winter in Armenia, southern Caucasus, and to explore its relationship with environmental features, such as land use and topography. During January 2012, we collected data by carrying out 15 roadside counts along which we calculated three community parameters: the relative abundance, the species richness, and the species diversity. Then, we carried out a multiple linear regression with the Information-Theoretic Approach, to explain the relationship between the parameters and environmental variables. Besides, we computed a Canonical Correspondence Analysis (CCA) between the species and the environment around their observations. As a general pattern, the community was associated with permanent crops, maybe because of their heterogeneity, which in turn allows them to support higher densities of prey during the winter. The most abundant species was the Black Kite (Milvus migrans), followed by the Common Kestrel (Falco tinnunculus) and the Griffon Vulture (Gyps fulvus). To our knowledge, this is one of the first studies investigating the wintering raptor community in the Caucasus, with raptors generally studied in this area during the breeding season and migration.

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