scholarly journals An Attitude Determination Method for Comprehensive Inspection Vehicle Based on Track Profile Registration

2017 ◽  
Vol 45 (4) ◽  
pp. 181
Author(s):  
Yumei Zhang ◽  
Dalin Zhang

The attitude of the comprehensive inspection vehicle is one of the important factors that affect the accuracy of the inspection of metro line infrastructure, meanwhile the metro environment restricts the employment of common attitude determination methods. A new method of attitude determination is presented in this paper, which takes the track as reference and employs non-contact measurement to acquire the track profile simulta-neously. By registration of measurement track profile and the standard track profile, the relative position between the vehicle and the track reference can be calculated; and the instantaneous attitude of the vehicle can be determined by the matrix inverse calculation. The performance of the method is verified by an experiment using the road-rail comprehensive inspection vehicle.

2021 ◽  
pp. 1-27
Author(s):  
Anna Naszodi ◽  
Francisco Mendonca

Abstract We develop a method which assumes that marital preferences are characterized either by the scalar-valued measure proposed by Liu and Lu, or by the matrix-valued generalized Liu–Lu measure. The new method transforms an observed contingency table into a counterfactual table while preserving its (generalized) Liu–Lu value. After exploring some analytical properties of the new method, we illustrate its application by decomposing changes in the prevalence of homogamy in the US between 1980 and 2010. We perform this decomposition with two alternative transformation methods as well where both methods capture preferences differently from Liu and Lu. Finally, we use survey evidence to support our claim that out of the three considered methods, the new transformation method is the most suitable for identifying the role of marital preferences at shaping marriage patterns. These data are also in favor of measuring assortativity in preferences à la Liu and Lu.


IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 181842-181854 ◽  
Author(s):  
Yi Zhang ◽  
Hongyang Zhang ◽  
Kuidong Gao ◽  
Wenbo Xu ◽  
Qingliang Zeng

2018 ◽  
Vol 72 (2) ◽  
pp. 483-502
Author(s):  
Hongtao Wu ◽  
Xiubin Zhao ◽  
Chunlei Pang ◽  
Liang Zhang ◽  
Bo Feng

A priori attitude information can improve the success rate and reliability of Global Navigation Satellite System (GNSS) multi-antennae attitude determination. However, a priori attitude information is nonlinear, and integrating a priori information into the objective function rigorously will increase the complexity of an ambiguity domain search, such as the Multivariate Constrained-Least-squares Ambiguity Decorrelation Adjustment (MC-LAMBDA) method. In this paper, a new method based on attitude domain search is presented to make use of the a priori attitude angle information with high efficiency. First, the a priori information of pitch and roll is integrated into the search process to derive the analytic search step for attitude angle, and the integer candidates are determined by traversal search in the three-dimensional attitude domain. Then, the objective function is parameterised with Euler angles, and a non-iterative approximate method is utilised to simplify the iterative computation in calculating objective function values. Experimental results reveal that compared to the MC-LAMBDA method, our new method has the same success rate and reliability, but higher efficiency in making use of a priori attitude information.


Rodriguésia ◽  
2021 ◽  
Vol 72 ◽  
Author(s):  
Liliana Aparecida Ribeiro Martins ◽  
Rodrigo Monte Lorenzoni ◽  
Ronald Martins Pereira Júnior ◽  
Fábio Demolinari de Miranda ◽  
Milene Miranda Praça Fontes ◽  
...  

Abstract Plant species that show gregarious spatial distribution and endemism to the Atlantic Forest, such as Dorstenia elata, are particularly sensitive to the effects of genetic diversity loss. In the present study, we aimed to quantify the genetic diversity in native populations of this species in an Atlantic Forest remnant. The sample included three aggregates of individuals, and molecular characterization was performed with twelve ISSR primers. Intrapopulation analyses were based on the calculation of the Shannon index; total expected heterozygosity and the matrix of distances between pairs of individuals were also calculated. The obtained grouping dendrogram evinced the formation of two groups. Interpopulation investigations were based on the analysis of molecular variance and the estimate of historical gene flow. The results demonstrate that one group comprised the genotypes from two subpopulations, and the other contained exclusively the genotypes of a third subpopulation. The greatest genetic variability was observed within rather than among populations, indicating that the geographical distance and the road that divides the studied populations are not causing loss of genetic diversity.


2021 ◽  
Author(s):  
Michael Prendergast

This paper describes a new method for performing secure encryption of blocks of streaming data. This algorithm is an extension of the RSA encryption algorithm. Instead of using a public key (e,n) where n is the product of two large primes and e is relatively prime to the Euler Totient function, φ(n), one uses a public key (n,m,E), where m is the rank of the matrix E and E is an invertible matrix in GL(m,φ(n)). When m is 1, this last condition is equivalent to saying that E is relatively prime to φ(n), which is a requirement for standard RSA encryption. Rather than a secret private key (d,φ(n)) where d is the inverse of e (mod φ(n)), the private key is (D,φ(n)), where D is the inverse of E (mod (φ(n)). The key to making this generalization work is a matrix generalization of the scalar exponentiation operator that maps the set of m-dimensional vectors with integer coefficients modulo n, onto itself.


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