scholarly journals Realization of GPS Dynamic Hijacking Based on Software Radio

2021 ◽  
Vol 2083 (2) ◽  
pp. 022026
Author(s):  
Zhihui Wang ◽  
Fan Yang
Keyword(s):  
Frequency Shift ◽  
Calculation Method ◽  
Software Radio ◽  
Gps Positioning ◽  
Theoretical Support ◽  
Wide Range ◽  
Implementation Method ◽  
Property Losses ◽  
Modulation Methods

Abstract GPS positioning technology has a wide range of use scenarios, but due to the known characteristics of GPS signal open reception and modulation methods, many solutions can easily deceive GPS signals. Once this technology is abused in violation of regulations, it may cause major safety and property losses. In order to better study the anti-hijacking technology of PGS signals, this article starts with the generative dynamic hijacking of PGS, gives the implementation method based on software radio, and further learns the code phase and dopper between asynchronous hijacking and synchronous hijacking through software radio. The compensation calculation method of Leer frequency shift parameters, and verified the effect of the software radio’s GPS dynamic hijacking implementation method through examples, and provide theoretical support for the design and improvement of future anti-hijacking systems.

A Calculation Method of Magnetic Anomaly Field Distribution of Ellipsoid with Arbitrary Posture

2021 ◽  
Author(s):  
Song-tong Han ◽  
Bo Zhang ◽  
Xiao-li Rong ◽  
Lei-xiang Bian ◽  
Guo-kai Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Anomaly ◽  
Field Distribution ◽  
Calculation Method ◽  
Gravity Potential ◽  
Anomaly Field ◽  
Finite Element Software ◽  
Wide Range ◽  
Distribution Equation

The ellipsoidal magnetization model has a wide range of application scenarios. For example, in aviation magnetic field prospecting, mineral prospecting, seabed prospecting, and UXO (unexploded ordnance) detection. However, because the existing ellipsoid magnetization formula is relatively complicated, the detection model is usually replaced by a dipole. Such a model increases the error probability and poses a significant challenge for subsequent imaging and pattern recognition. Based on the distribution of ellipsoid gravity potential and magnetic potential, the magnetic anomaly field distribution equation generated by the ellipsoid is deduced by changing the aspect ratio, making the ellipsoid equivalent to a sphere. The result of formula derivation shows that the two magnetic anomaly fields are consistent. This paper uses COMSOL finite element software to model UXO, ellipsoids, and spheres and analyzes magnetic anomalies. The conclusion shows that the ellipsoid model can completely replace the UXO model when the error range of 1nT is satisfied. Finally, we established two sets of ellipsoids and calculated the magnetic anomalous field distributions on different planes using deduction formulas and finite element software. We compared the experimental results and found that the relative error of the two sets of data was within [Formula: see text]‰. Error analysis found that the error distribution is standardized and conforms to the normal distribution. The above mathematical analysis and finite element simulation prove that the calculation method is simple and reliable and provides a magnetic field distribution equation for subsequent UXO inversion.

Marx 200 years on

2018 ◽  
Vol 29 (4) ◽  
pp. 481-500
Author(s):  
Robert Dixon
Keyword(s):  
Karl Marx ◽  
Economic Surplus ◽  
Jel Codes ◽  
Wage Share ◽  
Theoretical Support ◽  
Wide Range ◽  
Production And Distribution ◽  
Unpaid Labour ◽  
Theory Of Value

This year marks the 200th anniversary of the birth of Karl Marx, the last of the classical political economists. This article aims to mark the occasion by drawing attention to some of his key works in economics and to present some of his ideas in a way that will make sense to readers not familiar with or very much interested in the complexities of the labour theory of value. I begin with a brief biography and a summary of his main works in economics. I then explore in some detail ideas related to the economic surplus, unpaid labour and exploitation, and attempt to tease out the implications of his analysis for the determination of the wage share. While I argue that Marx has not succeeded in providing adequate theoretical support for his prediction that the wage share will fall as capital accumulates, he has nonetheless provided a very interesting and insightful collection of ideas by which we may, even today, approach a wide range of issues relating to production and distribution. JEL Codes: B14, B31, D33

The status of but in documentaries and their Romanian subtitles

2020 ◽  
Vol 13 ◽  
pp. 133-152
Author(s):  
Mihaela MLADENOVICI (IONESCU)
Keyword(s):  
Target Language ◽  
Theoretic Approach ◽  
Source Language ◽  
Complex Word ◽  
Theoretical Support ◽  
Wide Range ◽  
The Status ◽  
Discourse Connectives ◽  
Core Meaning

The aim of this article is to describe the status of but functioning as a connector of contrast in documentaries and their subtitles, with English as the source language and Romanian as the target language. But is a complex word, serving as a connectivity evince, comprehension facilitator and argumentative indicator, acquiring therefore a host of roles, both within and beyond the sentence. As theoretical support, I will employ the idea put forward by Fraser (2009) that but conveys one core meaning, that of contrast and that pragmatically it has a wide range of interpretations which are to be inferred from the context, but I will also draw on the Relevance Theoretic approach to discourse connectives elaborated by Diane Blakemore (1987, 2002, 2004) who referred to these functional items as encoding procedures rather than concepts, their meaning being interpreted based on what they indicate, not on what they describe. As for its role in argumentation, but will be analysed within the pragma-dialectical framework. Using my own research, but also that carried out by Halliday and Hasan (1976), Quirk et al. (1985), Biber et al. (1999) and Fraser (1999, 2009), I have made a list of connectors of contrast and the conclusion I have reached so far is that there are roughly 66 such items in English. However, in documentaries, there is a tendency to use only a few of them, approximately 15 (but, yet, still, however, though, although, even though, despite, rather, in reality, better, while, whereas). But is at the top of the list, having by far the largest number of occurrences and therefore being of outmost importance in constructing the idea of contrast. However, there is a certain inconsistency with respect to the rendition but in Romanian. When it functions at the level of the sentence, it is very rarely omitted as it displays a strong syntactic dependence. Conversely, when it functions at the discourse level, its translation does not always have the same degree of salience, in certain cases the subtitler resorting to its omission as part of his/her strategy of text condensation. I will identify and analyse the types of situations in which but is omitted in Romanian and those in which it is not, focusing on its role according to the various patterns typical of documentaries that include this connector.

A Comparison of Theoretical and Experimental Pressure Distributions on Bodies of Revolution

1980 ◽  
Vol 24 (01) ◽  
pp. 60-65
Author(s):  
A. J. Smits ◽  
S. P. Law ◽  
P. N. Joubert
Keyword(s):  
Calculation Method ◽  
The Body ◽  
Viscous Effects ◽  
Bodies Of Revolution ◽  
Pressure Distributions ◽  
Wide Range ◽  
The Right ◽  
Right Order ◽  
Axisymmetric Bodies ◽  
Experimental Pressure

A wide range of experimental pressure distributions along axisymmetric bodies was compared with the results of Landweber's potential flow calculation method. Apart from certain viscous effects, some discrepancies were found, and it is shown that blockage corrections are of the right order to account for these discrepancies. The calculation method was also used to show that the pressure distribution over the nose of the body is largely independent of the tail shape, and vice versa.

Analysis of Measurements in Vaned Diffusers of Centrifugal Compressors

1988 ◽  
Vol 110 (1) ◽  
pp. 115-121 ◽  
Author(s):  
W. Stein ◽  
M. Rautenberg
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Calculation Method ◽  
Geometric Parameters ◽  
Variable Geometry ◽  
Centrifugal Compressors ◽  
Wide Range ◽  
Performance Curves ◽  
Different Types ◽  
Flow Phenomena

In vaned diffusers of centrifugal compressors many different flow phenomena interfere with one another, and different geometric parameters influence the flow field. Variations of these parameters allow the designer to optimize the diffuser for a certain application or to use a variable geometry for controlling the stage over a wide range. Two vaned diffusers that differ only in their passage widths are investigated using different types of measuring technique, in order to analyze the flow structure and to use it as a verification of a calculation method that allows detailed predictions of flow field parameters inside the diffuser, by taking into account geometric variations. Using this method predictions of the flow field of a variable geometry diffuser are made and are compared with the measured performance curves of the stage.

Dynamic asymptotic model of rolling bearings with a single fault in the inner raceway

2021 ◽  
Vol 13 (10) ◽  
pp. 168781402110522
Author(s):  
Yunlong Li ◽  
Zhinong Li ◽  
Danyang Tian ◽  
Junyong Tao
Keyword(s):  
Fault Diagnosis ◽  
Dynamic Analysis ◽  
Reliability Analysis ◽  
Dynamic Characteristics ◽  
Calculation Method ◽  
Asymptotic Model ◽  
Rolling Bearings ◽  
Single Fault ◽  
Theoretical Support ◽  
Rolling Element

In the previous models of rolling bearings with a single fault, the displacement deviation caused by the collision of the fault to the rolling element changes instantly. However, the displacement deviation should change gradually. Here, the asymptotic idea is introduced to describe the change of the displacement deviation. The calculation method of the deviation is given. An asymptotic model of rolling bearings with an inner raceway fault is constructed. Then, the simulation of the SKF6205 bearing with a single fault is carried out. The differences between the previous model and the asymptotic model for the responses and the displacement deviation are compared. The effects of the speed and fault size on the dynamic characteristics are analyzed. Finally, the experiments are carried out to corroborate the rationality of the constructed model. The research results can provide theoretical support for the dynamic analysis, fault diagnosis, and reliability analysis of rolling bearings.

DIFFRACTION RESPONSE FOR NONZERO SEPARATION OF SOURCE AND RECEIVER

Geophysics ◽  
1977 ◽  
Vol 42 (6) ◽  
pp. 1158-1176 ◽  
Author(s):  
John R. Berryhill
Keyword(s):  
Seismic Data ◽  
Potential Method ◽  
Acoustic Wave Equation ◽  
Theoretical Support ◽  
Separation Theory ◽  
Wide Range ◽  
Diffraction Patterns ◽  
Subsurface Geometry ◽  
Kirchhoff Integral ◽  
Special Case

An existing theory based on the Kirchhoff retarded potential method makes distinctive predictions relating the amplitude characteristics of diffraction patterns to the geometry of subsurface reflectors. The application of this theory to seismic stacked sections would offer the geophysicist useful information to be included in subsurface interpretations. However, a possible barrier to such applications arises from the fact that the theory as originally put forth applies only to data recorded with zero source‐receiver separation, whereas stacked sections are produced by averaging data recorded over a wide range of shot‐geophone distances. To deal properly with seismic data us actually recorded, it is desirable to have a theory of diffraction amplitudes formulated for nonzero separation of source and receiver. This paper develops such a theory through an appropriate extension of the Kirchhoff approach. By expressing the problem in a special coordinate system, the Kirchhoff integral solution of the acoustic wave equation is reduced to a time‐domain convolution of the source wavelet with an operator recognized as the impulse response of the subsurface geometry under consideration. Impulse responses are computed explicitly for an infinite reflecting plane and for diffracting edges perpendicular and parallel to the source‐receiver axis. The nonzero‐separation theory is compared to the zero‐separation theory through numerical evaluation of the relevant formulas, and the latter is shown to be a special case of the former, as it should be. More importantly, the unexpected conclusion emerges that diffraction amplitudes at nonzero source‐receiver separation are controlled almost exclusively by the location of the source‐receiver midpoint. Since the data summed together in stacking all share a common shot‐geophone midpoint, the diffraction amplitudes on the stacked trace should behave in good approximation to the zero‐separation theory. Theoretical support is thus obtained for applying the zero‐separation theory to stacked seismic data.

scholarly journals CALCULATION METHOD OF REAL ACTIVITY COEFFICIENTS OF IONS BY EXAMPLE OF HYDROGEN AND CHLORINE IONS IN AQUEOUS HCl SOLUTIONS

2017 ◽  
Vol 60 (3) ◽  
pp. 29
Author(s):  
Anastasia A. Fedorova ◽  
Nikolaiy Yu. Sharonov ◽  
Dmitry V. Filippov
Keyword(s):  
Activity Coefficients ◽  
Calculation Method ◽  
Energy State ◽  
Thermodynamic Characteristics ◽  
Bulk Solution ◽  
Interphase Surface ◽  
Real Activity ◽  
The Real ◽  
Wide Range ◽  
Chlorine Ions

In this paper, we proposed a calculating method of the real individual activity coefficients. To calculate the energy of the ion, transfer through the interface we offered to use the value of the electrolyte solution surface potential, and to use electronegativity elements values for accounting contribution of the charge transfer energy between the surface and the bulk solution. To verify the proposed equation, the activity coefficients of hydrogen and chlorine ions in an aqueous HCl solutions were calculated over a wide range of electrolyte concentrations. The Debye-Hückel equation within 2nd approximation describes satisfactorily the dependence of the activity coefficient on the electrolyte concentration for anions, but not reproduce the minimum on the curve for cations. This dependence for the cation H⁺ is most extremal, and namely it is the reason of the choice of HCl for the model calculation. The calculated values were compared with the data obtained from the results of determining the activity coefficients by experimental method of "vertical jet" [1]. The comparison showed that our proposed equation reproduces the character of the concentration dependence of real activity coefficients not for anion only but for cation as well. Previously we found, that at low concentrations of solutes up to 0.1 mol/kg the values of some thermodynamic characteristics are strongly determined by not the volume concentration of the electrolyte, but the restructuring of the solvent structure in the surface layer of the solution, and therefore, the changing the energy state of the molecules at the interphase surface. Hence, the number of cations and anions at the surface in the areas of high and low bulk concentrations of electrolyte also differ greatly. Obviously, the small variation between calculated and experimental values of the real activity coefficients may be connected with necessity of using at calculation the bulk and surface concentration of ions. For citation:Fedorovа A.A., Sharonov N.Yu., Filippov D.V. Calculation method of real activity coefficients of ions by example of hydrogen and chlorine ions in aqueous HCl solutions. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 29-35.

scholarly journals Flow Field Simulation and Efficiency Calculation of Muzzle Brake Based on ANSYS Fluent

2021 ◽  
Vol 261 ◽  
pp. 02022
Author(s):  
Zhen Wang
Keyword(s):  
Flow Field ◽  
Blast Wave ◽  
Calculation Method ◽  
High Efficiency ◽  
Wave Attenuation ◽  
Simulation Method ◽  
Ansys Fluent ◽  
Flow Field Simulation ◽  
Theoretical Support ◽  
Field Simulation

The development of advanced artillery needs to be combined with simulation means, so, traditional calculation method and the flow field simulation method was employed to calculate the efficiency of a largecaliber muzzle brake we designed, and the results achieved by these two methods were 47.8% and 49.3%, respectively. Further, the overpressure value 1 m away from the muzzle was obtained through flow field simulation, and the far-field overpressure value was calculated using blast wave attenuation equations. The result suggests that the blast wave from the designed muzzle brake has little harmful impact. This paper provides an intuitive calculation method of muzzle brake efficiency, also, it provides theoretical support for research of high efficiency muzzle brake and personnel protection onboard.

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