scholarly journals Analysis of the Azimuth Ambiguity and Imaging Area Restriction for Circular SAR Based on the Back-Projection Algorithm

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4920 ◽  
Author(s):  
Bang Du ◽  
Xiaolan Qiu ◽  
Lijia Huang ◽  
Songlin Lei ◽  
Bin Lei ◽  
...  
Keyword(s):  
Beam Width ◽  
Bp Algorithm ◽  
Projection Algorithm ◽  
Parameter Design ◽  
Observation Angle ◽  
Back Projection ◽  
Theoretical Support ◽  
Relationship Of ◽  
The Relationship ◽  
Small Observation

Circular synthetic aperture radar (CSAR) has a 360° observation capability on the central observation scenario. A typical way to process CSAR imaging is to cut data into small sub-apertures because most targets are only coherent at a very small observation angle. There are many sub-aperture imaging methods after development in recent years. The back-projection algorithm is widely used because it is simple and can be applied to an arbitrary trajectory. Because of the limitation of the Nyquist sampling frequency and influence of the antenna sidelobe, azimuth ambiguity is a phenomenon that may occur in the radar imaging process. The existing researches typically choose the back-projection (BP) imaging area according to the SAR platform flight path and the antenna beam width. The limitation of the CSAR imaging area and its azimuth ambiguity region are rarely analyzed theoretically. This paper focus on the sub-aperture imaging of CSAR, based on the BP algorithm, which derives the relationship of azimuth ambiguity with CSAR parameters such as the pause repeat frequency (PRF), slant range angle, velocity of radar platform, etc. This paper proposes an equation for the calculation of the azimuth ambiguity region and analyzes the limitations, which provides theoretical support for CSAR parameter design, imaging area selection, and azimuth ambiguity analysis.

scholarly journals Techniques for postmortem tenderisation in meat processing: effectiveness, application and possible mechanisms

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Haibo Shi ◽  
Fereidoon Shahidi ◽  
Jiankang Wang ◽  
Yan Huang ◽  
Ye Zou ◽  
...  
Keyword(s):  
Meat Industry ◽  
Meat Processing ◽  
Protein Biomarkers ◽  
Theoretical Support ◽  
Exogenous Enzymes ◽  
Home Cooking ◽  
Relationship Of ◽  
The Relationship ◽  
Combined Interventions ◽  
Calpain System

Abstract Developing efficient and promising tenderising techniques for postmortem meat is a heavily researched topic among meat scientists as consumers are willing to pay more for guaranteed tender meat. However, emerging tenderising techniques are not broadly used in the meat industry and, to some degree, are controversial due to lack of theoretical support. Thus, understanding the mechanisms involved in postmortem tenderisation is essential. This article first provides an overview of the relationship of ageing tenderisation and calpain system, as well as proteomics applied to identify protein biomarkers characterizing tenderness. In general, the ageing tenderisation is mediated by multiple biochemical activities, and it can exhibit better palatability and commercial benefit by combining other interventions. The calpain system plays a key role in ageing tenderisation functions by rupturing myofibrils and regulating proteolysis, glycolysis, apoptosis and metabolic modification. Additionally, tenderising techniques from different aspects including exogenous enzymes, chemistry, physics and the combined methods are discussed in depth. Particularly, innovation of home cooking could be recommended to prepare relatively tender meat due to its convenience and ease of operation by consumers. Furthermore, the combined interventions provide better performance in controlled tenderness. Finally, future trends in developing new tenderising techniques, and applied consideration in the meat processing industry are proposed in order to improve meat quality with higher economical value. Graphical abstract

scholarly journals A 3-D SAR Imaging Method Based on Back Projection Algorithm

2021 ◽  
Vol 2083 (3) ◽  
pp. 032050
Author(s):  
Qian Han ◽  
Pengbo Wang ◽  
Xinkai Zhou ◽  
Xinchang Hu ◽  
Yanan Guo
Keyword(s):  
3D Imaging ◽  
Bp Algorithm ◽  
Projection Algorithm ◽  
Imaging Method ◽  
Back Projection ◽  
Imaging Processing ◽  
Imaging Algorithm ◽  
Imaging Results ◽  
2D Imaging ◽  
Low Efficiency

Abstract 3D back projection (BP) algorithm is an imaging algorithm based on time domain echo data, which effectively solves the overlapping mask problem existing in 2D SAR. It can complete the imaging processing of echo signal under any geometry configuration, and has the advantages of high target focusing accuracy and high phase preservation. However, the high complexity and low efficiency of 3D BP imaging algorithm limit its application and development. In this paper, a 3d imaging method based on improved back projection algorithm is proposed. Aiming at the problem that existing imaging algorithms need 2D imaging first and then 3D imaging, an improved 3D BP algorithm is proposed to directly 3D imaging, which avoids 2d imaging processing. The proposed method simplifies the steps of the traditional 3D BP algorithm and improves the efficiency of the algorithm. The validity and effectiveness of the proposed method are verified by the 3d imaging results of simulated lattice targets.

Theories and Applications of Pulsed-Jet Drilling With Mechanical Specific Energy

SPE Journal ◽  
2016 ◽  
Vol 21 (01) ◽  
pp. 303-310 ◽  
Author(s):  
Wei Minghui ◽  
Li Gensheng ◽  
Shi Huaizhong ◽  
Shi Shuaishuai ◽  
Li Zhaokun ◽  
...  
Keyword(s):  
Specific Energy ◽  
Field Tests ◽  
Cleaning Efficiency ◽  
Pulsed Jet ◽  
Mechanical Specific Energy ◽  
Main Work ◽  
Theoretical Support ◽  
Relationship Of ◽  
The Relationship ◽  
Conventional Drilling

Summary Mechanical specific energy (MSE) is the amount of energy required to destroy a unit volume of rock. The main work of this study is to bring the hydraulic energy of a pulsed jet into an MSE model and further analyze the mechanism of improving the rate of penetration (ROP) for pulsed-jet drilling on the basis of the model. Laboratory experiments are used to obtain the relationship of bit hydraulic horsepower between pulsed jet and continuous jet, and then the MSE model of pulsed-jet drilling is established. According to the MSE theory, the major mechanisms of improving ROP in pulsed-jet drilling are changing the breaking strength of rock and improvement of downhole-cuttings-cleaning efficiency. Field tests and data presented in this study showed that this model could be used to evaluate drilling efficiency and identify abnormal conditions for pulsed-jet drilling. All tests were operated with similar parameters and on the same drilled formation. The field results illuminate that pulsed-jet drilling has higher drilling efficiency compared with conventional drilling. Moreover, the specific patterns for abnormal conditions can be detected in real time in the process of pulsed-jet drilling. This model is less ambiguous as well as robust. Therefore, it could provide theoretical support for the wide application of pulsed-jet drilling.

scholarly journals Proposing a theoretical framework to investigate the relationships between an organization and its environment

2007 ◽  
Vol 11 (1) ◽  
pp. 75-96 ◽  
Author(s):  
Ricardo Corrêa Gomes ◽  
Luciana de Oliveira Miranda Gomes
Keyword(s):  
Resource Dependence ◽  
Open Systems ◽  
Theoretical Models ◽  
Theoretical Framework ◽  
Extensive Literature ◽  
Theoretical Support ◽  
External Agents ◽  
And Performance ◽  
Relationship Of ◽  
The Relationship

This paper proposes a theoretical framework for investigating stakeholder theory in organizations. The organizations theory can be understood in three theoretical models: rationalist, natural and open systems. These models are presented to justify that organizations should be analyzed taking into account that social system aspects and the natural and open system models are employed. The applications of this paper rely upon the theoretical framework which is based on an extensive literature review comprising environment based theories. This paper would be of help to researchers examining the whole set of the relationship of organizations with their environment instead of only the relationships with external agents. Employing the theoretical basis presented in this analysis, the researcher will be able to identify both feasible theoretical sources for his/her studies and useful approaches for carrying on his/her investigations. The paper presents theories for explaining the organization's behavior and performance as being influenced by stakeholders who inhabit its environment. Resource dependence and institutional theory are employed to give theoretical support to the stakeholder. At the end of the paper, a diagram representing the theoretical framework is presented.

scholarly journals Can environmental regulation solve China's employment dilemma: Empirical analysis based on scale and structure effects

2021 ◽  
Author(s):  
Mengjie Li ◽  
Weijian Du
Keyword(s):  
Environmental Regulation ◽  
Institutional Environment ◽  
Environmental Regulations ◽  
Employment Structure ◽  
Theoretical Support ◽  
Regulation Policy ◽  
Enterprise Innovation ◽  
Internal And External Factors ◽  
Relationship Of ◽  
The Relationship

Abstract Whether the environmental regulation policy can achieve the double dividend of pollution control and employment promotion is a problem worthy of further discussion. This paper studies the effect of environmental regulation on employment scale and employment structure. Based on the matching data, the empirical results show that environmental regulations enhance the employment scale of enterprise. From the perspective of employment structure, labor redistribution, which is caused by environmental regulation, is mainly reflected in the employment creation and employment destruction effects, which lead to the optimization of the employment structure. Further research shows that environmental regulations expand employment scale but have different impacts on the employment structure in the developed and undeveloped regions of China. In addition, internal and external factors, such as enterprise innovation and institutional environment, may affect the relationship of environmental regulation and employment of enterprise. This paper provides theoretical support for the promotion of the construction of ecological civilizations and the solving of the employment dilemma.

The Influence and Simulation of Crank Shaft Length over Upper Knife Holder Trace of Rolling-Cut Bilateral Shear

2012 ◽  
Vol 572 ◽  
pp. 317-321
Author(s):  
Xian Jia ◽  
Zhi Bing Chu ◽  
Qing Xue Huang ◽  
Li Feng Ma
Keyword(s):  
Auxiliary Equipment ◽  
Shaft Length ◽  
Theoretical Support ◽  
Pure Rolling ◽  
Working Principle ◽  
Movement Trace ◽  
Shearing Mechanism ◽  
Relationship Of ◽  
The Relationship ◽  
Different Thickness

Rolling-cut bilateral shear is a sort of auxiliary equipment with arc upper blade performing pure rolling over flat lower one. The working principle are characterized as up-and-down movement of upper blade by crank shaft, after the rotation caused by the phase difference between two shafts, which makes upper blade rotate to adapt to steel shearing with different thickness. Through analysis the processing of rolling-cut bilateral shear and make the shearing mechanism simplify 8-linkage, and then the kinetics formula of shearing mechanism was established. The relationship of crank shaft length of rolling-cut bilateral shear in shearing process and movement trace of upper blade (shearing overlapping) was obtained as well as the change rule of length of linkage over upper blade, which provides the theoretical support for the design of rolling-cut bilateral shear.

Optimization of New Metal Gasket Design Based on Contact Width Involving Contact Stress Consideration

2011 ◽  
Vol 110-116 ◽  
pp. 4780-4787
Author(s):  
M. Agus Choiron ◽  
Shigeyuki Haruyama ◽  
K. Kaminishi
Keyword(s):  
Optimal Design ◽  
Taguchi Method ◽  
Optimum Design ◽  
Contact Stress ◽  
Orthogonal Array ◽  
Design Concept ◽  
Parameter Design ◽  
Contact Width ◽  
Relationship Of ◽  
The Relationship

The relationship of contact width and leakage had been found as design concept to optimize new metal gasket. By using this design concept, the limits of contact width for no leakage can be chosen. The optimize gasket shape can be developed by increasing of contact width. In this study, a gasket shape was optimized based on contact width as design concept and involving contact stress consideration. The design of experimentation (DOE) Taguchi method is used to analyses the effect of each parameter design and predict optimal design of new 25A metal gasket. The L18 orthogonal array was concerned to design experimental matrix for seven factors with three levels. The optimum design of gasket at 0 MPa mode is the model with OH = 4 mm, p1 = 3.5 mm, p2 = 4 mm, p3 = 4 mm, t = 1.2 mm, R = 3.5 mm and h = 0.4 mm. The optimum design of gasket at 400 MPa mode is the model with OH = 3 mm, p1 = 3.5 mm, p2 = 4.5 mm, p3 = 4.5 mm, t = 1.8 mm, R = 1.5 mm and h = 0.3 mm.

Measurement Error of Left-Turn Vehicle Trajectory by Video Detection

2013 ◽  
Vol 401-403 ◽  
pp. 1068-1073
Author(s):  
Bo Hang Liu ◽  
Xiao Xia Liu ◽  
Shi Jie Zhang
Keyword(s):  
Measurement Error ◽  
Research Field ◽  
Left Turn ◽  
Theoretical Support ◽  
Detection Technology ◽  
Video Detection ◽  
Transverse Distance ◽  
Vehicle Trajectory ◽  
Relationship Of ◽  
The Relationship

The video detection technology is a very active branch in the research field of machine vision, and the detection of vehicle trajectory by the stationary camera has become more and more important. However, there is little research on the measurement error of left-turn vehicles trajectory.This paper not only studies the relationship between the measurement error and longitudinal distance; but also relationship of measurement error and transverse distance. Their mathematical models are constructed and each of the variables in the models is analyzed. Then in the case analysis of certain intersection, the experimental results have shown that the proposed funtions can describe the relationship between measurement error and the parameters. It can provide the theoretical support for the measurement error problems of obtaining trajectory by video detection.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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