scholarly journals Error analyses of a multistatic meteor radar system to obtain a three-dimensional spatial-resolution distribution

2021 ◽  
Vol 14 (5) ◽  
pp. 3973-3988
Author(s):  
Wei Zhong ◽  
Xianghui Xue ◽  
Wen Yi ◽  
Iain M. Reid ◽  
Tingdi Chen ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Measurement Errors ◽  
Dimensional Space ◽  
Lower Thermosphere ◽  
Three Dimensional ◽  
Radar System ◽  
Meteor Radar ◽  
Radar Systems ◽  
Good Spatial Resolution ◽  
First Time

Abstract. In recent years, the concept of multistatic meteor radar systems has attracted the attention of the atmospheric radar community, focusing on the mesosphere and lower thermosphere (MLT) region. Recently, there have been some notable experiments using such multistatic meteor radar systems. Good spatial resolution is vital for meteor radars because nearly all parameter inversion processes rely on the accurate location of the meteor trail specular point. It is timely then for a careful discussion focused on the error distribution of multistatic meteor radar systems. In this study, we discuss the measurement errors that affect the spatial resolution and obtain the spatial-resolution distribution in three-dimensional space for the first time. The spatial-resolution distribution can both help design a multistatic meteor radar system and improve the performance of existing radar systems. Moreover, the spatial-resolution distribution allows the accuracy of retrieved parameters such as the wind field to be determined.

scholarly journals Error analyses of a multistatic meteor radar system to obtain a 3-dimensional spatial resolution distribution

2020 ◽  
Author(s):  
Wei Zhong ◽  
Xianghui Xue ◽  
Wen Yi ◽  
Iain M. Reid ◽  
Tingdi Chen ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Measurement Errors ◽  
Dimensional Space ◽  
Lower Thermosphere ◽  
Radar System ◽  
Meteor Radar ◽  
3 Dimensional ◽  
Radar Systems ◽  
Good Spatial Resolution ◽  
First Time

Abstract. In recent years, the concept of multistatic meteor radar systems has attracted the attention of the atmospheric radar community, focusing on the mesosphere and lower thermosphere (MLT). Recently, there have been some notable experiments using multistatic meteor radar systems (Chau et al., 2019; Spargo et al., 2019; Stober and Chau, 2015; Stober et al., 2018). Good spatial resolution is vital for meteor radars because nearly all parameter inversion processes rely on the accurate location of the meteor trail reflecting points. It is timely then for a careful discussion focussed on the error distribution of multistatic meteor radar systems. In this study, we discuss the measurement errors that affect the spatial resolution and obtain the resolution distribution in 3-dimensional space for the first time. The spatial resolution distribution can both help design a multistatic meteor radar system and improve the performance of existing radar systems. Moreover, the spatial resolution distribution allows the accuracy of retrieved parameters such as the wind field to be determined.

Spline approximation of unequal aeromagnetic survey data with the use of UAV on spatially inhomogeneous networks when solving problems of archaeological exploration

2021 ◽  
pp. 18-30
Author(s):  
D. N. Gapeev ◽  
M. I. Epov ◽  
A. A. Tishkin ◽  
A. P. Firsov ◽  
Ya. V. Frolov ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Spline Interpolation ◽  
Dimensional Space ◽  
Spline Approximation ◽  
Three Dimensional ◽  
Archaeological Site ◽  
Aeromagnetic Data ◽  
Aeromagnetic Survey ◽  
Spatially Inhomogeneous ◽  
Three Dimensional Space

The article discusses an approach to get a regular cube of data in context of aeromagnetic survey. It is based on spline approximation with nodes on an irregular grid in three-dimensional space. To construct approximation spline, information on measurement errors is additionally used, which makes it possible to reduce the number of parameters as opposed to spline interpolation. This approach was tested on experimental aeromagnetic data from archaeological site Ivanovka-I.

Anisotropic Mechanical and Thermal Properties of Nd2SrAl2O7

2012 ◽  
Vol 512-515 ◽  
pp. 975-979
Author(s):  
J. Feng ◽  
Z.C. Huang ◽  
R. Zhou ◽  
W. Pan
Keyword(s):  
Thermal Conductivity ◽  
Density Functional ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Double Perovskite ◽  
Ceramic Materials ◽  
Mechanical And Thermal Properties ◽  
3D Space ◽  
Long Time ◽  
First Time

For a long time since the anisotropy basically confined to a single crystal, used as a polycrystalline ceramic materials generally considered to be isotropic. In this paper, the anisotropic mechanical, thermal expansion coefficient and thermal conductivity of a double perovskite slab-rocksalt layer Nd2SrAl2O7 was studied by first principles as an example. The method is using density functional theory (DFT) and crystal parameters, which has been used to calculate the modulus of elasticity of anisotropic in a three-dimensional space. While combined with traditional thermal conductivity theory, we have obtained the tensor of thermal diffusion, thermal conductivity in 3D space for the first time in the world within no. The results are in good agreement with the experiment. The advantage of method is avoiding the difficulty of experimental measurement, reducing the time and obtaining relatively accurate results.

A unified procedure for construction of theories of deformable media. II. Generalized continua

1995 ◽  
Vol 448 (1934) ◽  
pp. 357-377 ◽  
Keyword(s):  
Solid Mechanics ◽  
Dimensional Space ◽  
Effective Means ◽  
Three Dimensional ◽  
The Body ◽  
Generalized Continua ◽  
Deformable Media ◽  
Material Points ◽  
Two Stages ◽  
First Time

In contrast to classical theories discussed in the accompanying paper (part I), the present paper deals exclusively with generalized continua, a term that refers to a body embedded in a euclidean three-dimensional space with each of its material points endowed with additional kinematic structure. Such generalized continua are conveniently identified here by Cosserat (or directed ) continua in which the additional structure is represented by independent director fields and the material domain of the body manifold is classified according to the four categories: (A) a three-dimensional volume, (B) a two-dimensional surface, (C) a one-dimensional space curve and (D) a point. In the derivation of a thermomechanical theory for each of these categories, we use the same unified procedure as in part I but now the various energies that enter the balance of energy must be modified to include additional kinetic ingredients. New theories of this kind have increasingly provided, over the last three decades, effective means of formulating and studying new behaviour of materials (in both fluid and solid mechanics) that were not previously possible by the classical theories. Our attention is first focused in the development of the theory for the first category and this is discussed in two stages: first for a Cosserat continuum with a single director and then for N directors. Our derived results include for the first time a derivation from the balance of energy of balances of director momenta and balances of entropies (in the presence of more than one independent temperature field). The treatments of categories (B) to (D) are somewhat shorter since their developments are formally similar to that of category (A).

scholarly journals Visualization and quantification of mimetic musculature via DiceCT

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9343
Author(s):  
Edwin Dickinson ◽  
Emily Atkinson ◽  
Antonio Meza ◽  
Shruti Kolli ◽  
Ashley R. Deutsch ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Future Studies ◽  
Communicative Behaviors ◽  
Contrast Enhanced ◽  
The Face ◽  
Enhanced Computed Tomography ◽  
First Time ◽  
Contrast Enhanced Computed Tomography ◽  
Three Dimensional Space

The muscles of facial expression are of significant interest to studies of communicative behaviors. However, due to their small size and high integration with other facial tissues, the current literature is largely restricted to descriptions of the presence or absence of specific muscles. Using diffusible iodine-based contrast-enhanced computed tomography (DiceCT) to stain and digitally image the mimetic mask of Eulemur flavifrons (the blue-eyed black lemur), we demonstrate—for the first time—the ability to visualize these muscles in three-dimensional space and to measure their relative volumes. Comparing these data to earlier accounts of mimetic organization with the face of lemuroidea, we demonstrate several novel configurations within this taxon, particularly in the superior auriculolabialis and the posterior auricularis. We conclude that DiceCT facilitates the study these muscles in closer detail than has been previously possible, and offers significant potential for future studies of this anatomy.

scholarly journals An Efficient Hybrid RSS-AoA Localization for 3D Wireless Sensor Networks

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2121 ◽  
Author(s):  
Thu L. N. Nguyen ◽  
Tuan D. Vy ◽  
Yoan Shin
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Measurement Errors ◽  
Dimensional Space ◽  
Weighted Least Squares ◽  
Three Dimensional ◽  
Path Loss ◽  
Wireless Sensor ◽  
Angle Of Arrival ◽  
Localization Scheme

Wireless sensor networks (WSNs) enable many applications such as intelligent control, prediction, tracking, and other communication network services, which are integrated into many technologies of the Internet-of-Things. The conventional localization frameworks may not function well in practical environments since they were designed either for two-dimensional space only, or have high computational costs, or are sensitive to measurement errors. In order to build an accurate and efficient localization scheme, we consider in this paper a hybrid received signal strength and angle-of-arrival localization in three-dimensional WSNs, where sensors are randomly deployed with the transmit power and the path loss exponent unknown. Moreover, in order to avoid the difficulty of solving the conventional maximum-likelihood estimator due to its non-convex and highly complex natures, we derive a weighted least squares estimate to estimate jointly the location of the unknown node and the two aforementioned channel components through some suitable approximations. Simulation results confirm the effectiveness of the proposed method.

scholarly journals A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ravirai Jangir ◽  
Nekkanti Sitaram ◽  
Ct Gajanan
Keyword(s):  
Measurement Errors ◽  
Three Dimensional ◽  
Lookup Table ◽  
Three Dimensional Flow ◽  
Velocity Gradients ◽  
Good Spatial Resolution ◽  
Large Pressure ◽  
Flow Gradient ◽  
Maximum Absolute Errors ◽  
Calibration Coefficients

A miniature four-hole probe with a sensing area of 1.284 mm2to minimise the measurement errors due to the large pressure and velocity gradients that occur in highly three-dimensional turbomachinery flows is designed, fabricated, calibrated, and validated. The probe has good spatial resolution in two directions, thus minimising spatial and flow gradient errors. The probe is calibrated in an open jet calibration tunnel at a velocity of 50 m/s in yaw and pitch angles range of ±40 degrees with an interval of 5 degrees. The calibration coefficients are defined, determined, and presented. Sensitivity coefficients are also calculated and presented. A lookup table method is used to determine the four unknown quantities, namely, total and static pressures and flow angles. The maximum absolute errors in yaw and pitch angles are 2.4 and 1.3 deg., respectively. The maximum absolute errors in total, static, and dynamic pressures are 3.4, 3.9, and 4.9% of the dynamic pressures, respectively. Measurements made with this probe, a conventional five-hole probe and a miniature Pitot probe across a calibration section, demonstrated that the errors due to gradient and surface proximity for this probe are considerably reduced compared to the five-hole probe.

scholarly journals Discussion about the effect of digital plants library on the plants landscape restoration in Yuanmingyuan

2015 ◽  
Vol XL-5/W7 ◽  
pp. 43-48
Author(s):  
L. Bing ◽  
S. Guxin ◽  
L. Gongli
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
System Construction ◽  
Landscape Restoration ◽  
Classical Work ◽  
Digital Restoration ◽  
Unique Style ◽  
Chinese Classical Garden ◽  
First Time ◽  
Three Dimensional Space

Chinese classical garden emphasizes not only the construction of building, mountains and rivers, spring and stone landscape but also the selection and configuration mode of the plant species. Yuanmingyuan, a classical work of Chinese garden art, is of both the magnificence of northern royal garden and the delicacy of southern private garden. The plants landscape in Yuanmingyuan also has its own unique style. But it is regretful that after several disasters, it nearly disappears just as other building clusters. The Re- Yuanmingyuan group re-presents the plants landscape of Yuanmingyuan through investigation, restoration and three-dimensional space generation, and makes proposal about the concept of digital plants library for the first time with the expectation to provide basic support for the digital restoration of cultural heritage by establishing the plants library. The paper also introduces the process of digital plants library system construction as well as the significance of the library construction for the landscape restoration in Yuanmingyuan and even the northern royal garden.

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