scholarly journals Numerical Inverse Transformation Methods for Z-Transform

Mathematics ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 556
Author(s):  
Illés Horváth ◽  
András Mészáros ◽  
Miklós Telek
Keyword(s):  
Contour Integral ◽  
Engineering Practice ◽  
Inverse Transformation ◽  
Integral Approximation ◽  
Point Of Interest ◽  
New Variant ◽  
Long Time ◽  
Transformation Methods ◽  
Z Transformation

Numerical inverse Z-transformation (NIZT) methods have been efficiently used in engineering practice for a long time. In this paper, we compare the abilities of the most widely used NIZT methods, and propose a new variant of a classic NIZT method based on contour integral approximation, which is efficient when the point of interest (at which the value of the function is needed) is smaller than the order of the NIZT method. We also introduce a vastly different NIZT method based on concentrated matrix geometric (CMG) distributions that tackles the limitations of many of the classic methods when the point of interest is larger than the order of the NIZT method.

scholarly journals Subway Gearbox Fault Diagnosis Algorithm Based on Adaptive Spline Impact Suppression

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 660
Author(s):  
Zhongshuo Hu ◽  
Jianwei Yang ◽  
Dechen Yao ◽  
Jinhai Wang ◽  
Yongliang Bai
Keyword(s):  
Fault Diagnosis ◽  
Spline Interpolation ◽  
Reference Value ◽  
High Amplitude ◽  
Engineering Practice ◽  
Negative Effects ◽  
Short Term ◽  
Time Domain Signal ◽  
Gearbox Vibration ◽  
Long Time

In the signal processing of real subway vehicles, impacts between wheelsets and rail joint gaps have significant negative effects on the spectrum. This introduces great difficulties for the fault diagnosis of gearboxes. To solve this problem, this paper proposes an adaptive time-domain signal segmentation method that envelopes the original signal using a cubic spline interpolation. The peak values of the rail joint gap impacts are extracted to realize the adaptive segmentation of gearbox fault signals when the vehicle was moving at a uniform speed. A long-time and unsteady signal affected by wheel–rail impacts is segmented into multiple short-term, steady-state signals, which can suppress the high amplitude of the shock response signal. Finally, on this basis, multiple short-term sample signals are analyzed by time- and frequency-domain analyses and compared with the nonfaulty results. The results showed that the method can efficiently suppress the high-amplitude components of subway gearbox vibration signals and effectively extract the characteristics of weak faults due to uniform wear of the gearbox in the time and frequency domains. This provides reference value for the gearbox fault diagnosis in engineering practice.

The Calculation Method and Experimental Research on Throttling Pressure Drop during Kill a Well

2012 ◽  
Vol 229-231 ◽  
pp. 495-498
Author(s):  
Hui Xin Liu ◽  
Xian Min Yang ◽  
Cheng Tao Li ◽  
Xiang Cheng
Keyword(s):  
Pressure Drop ◽  
Calculation Method ◽  
Engineering Practice ◽  
Exploration Process ◽  
Throttle Valve ◽  
Long Time ◽  
Valve Opening ◽  
Casing Pressure ◽  
The Relationship ◽  
Control Accuracy

There is a common problem during kill a well, which is how to quickly and accurately control the surface casing pressure according to the requirements for killing a well. A step-by-step exploration process is employed on operation sites. Continuously adjusting throttle valve to acquire surface casing pressure may lead to failure of kill operation because of its long time and low control accuracy. Obviously, if the calculation problems of throttling drawdown can be resolved,the relationship between drawdown and throttle valve opening can be found and the course of explorating can be converted into a straight course.Then the success rate of killing well can be improved. More importantly, this can make automatic controll of surface casing pressure possible. The paper built the calculation method of throttling pressure drop by theoretical analysis and verified the calculation method by adopting it into field test. The result has showed that the calculation method of throttling pressure drop coincides with experimental results and it can be used in engineering practice.

scholarly journals The Method of Solving Structural Reliability with Multiparameter Correlation Problem

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Juan Du ◽  
Haibin Li ◽  
Yun He
Keyword(s):  
Neural Network ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Copula Function ◽  
Information Criteria ◽  
Correlation Structure ◽  
Engineering Practice ◽  
Inverse Transformation ◽  
Correlation Parameter ◽  
Structure Reliability

Correlation among variables must be considered to accurately reflect the level of structure reliability. This problem has referential value to engineering practice and has attracted attention from relevant scholars and industries. In this paper, Copula function was used to build the joint probability density function among all variables. The key is to describe the correlation among variables, solve the correlation parameter θ of Copula function, and select the type of correlation structure among variables. The correlation parameter θ of Copula function was solved using Pearson linear correlation coefficient and maximum likelihood estimation. Based on the Akaike information criteria (AIC) and Bayesian information criteria (BIC), the optimal Copula function was selected, and the correlation structure among variables was determined. Monte Carlo method, which is based on Nataf inverse transformation, was introduced and used to evaluate the reliability of the correlated variable. Finally, this paper proposed the reliability calculation method based on dual neural network and direct integration by establishing the dual neural network of original and integrand functions. Compared with the Monte Carlo method, the proposed method can be utilized to efficiently and precisely calculate the structure reliability of multiple correlated random variables.

scholarly journals Coordinate references for the indoor/outdoor seamless positioning

2018 ◽  
Vol 1 ◽  
pp. 1-7
Author(s):  
Ling Ruan ◽  
Ling Zhang ◽  
Yi Long ◽  
Fei Cheng
Keyword(s):  
Reference Frame ◽  
Trajectory Analysis ◽  
Calibration Method ◽  
Indoor Positioning ◽  
Research Focus ◽  
System Establishment ◽  
Long Time ◽  
Seamless Positioning ◽  
Transformation Methods ◽  
Indoor And Outdoor

Indoor positioning technologies are being developed rapidly, and seamless positioning which connected indoor and outdoor space is a new trend. The indoor and outdoor positioning are not applying the same coordinate system and different indoor positioning scenes uses different indoor local coordinate reference systems. A specific and unified coordinate reference frame is needed as the space basis and premise in seamless positioning application. Trajectory analysis of indoor and outdoor integration also requires a uniform coordinate reference. However, the coordinate reference frame in seamless positioning which can applied to various complex scenarios is lacking of research for a long time. In this paper, we proposed a universal coordinate reference frame in indoor/outdoor seamless positioning. The research focus on analysis and classify the indoor positioning scenes and put forward the coordinate reference system establishment and coordinate transformation methods in each scene. And, through some experiments, the calibration method feasibility was verified.

scholarly journals Method of determining the optimal version of the piezometer of gas distribution networks of medium and high pressure

2021 ◽  
Vol 263 ◽  
pp. 04027
Author(s):  
Viktor Zhila ◽  
Aleksey Klochko
Keyword(s):  
Pressure Drop ◽  
Economic Effect ◽  
Distribution Networks ◽  
Correct Choice ◽  
Engineering Practice ◽  
Gas Pipelines ◽  
Gas Distribution ◽  
Industrial Enterprises ◽  
Stage Scheme ◽  
Long Time

The article deals with the issues of determining the optimal type of piezometric pressure graph in high-and medium-pressure gas pipelines in the design of gas distribution networks. Along with the most commonly used ways to reduce the cost of building gas distribution networks by finding the optimal configuration of gas pipelines, which give a great economic and environmental effect, it is necessary to rationally use the pressure drop provided to the network. This step in engineering practice allows you to additionally get money savings. The use of various schemes for supplying consumers with gas in cities and villages also has a great economic effect, but modern equipment allows you to make the transition to a single-stage scheme of gas distribution networks for cities. When designing gas distribution networks, the available pressure drop can be used by implementing various technical solutions, but the correct choice of pressures in the nodal points contributes to an economic effect. The designed configuration of the gas distribution network with the adopted type of piezometric graph can ensure reliable operation for a long time. The results obtained are recommended for use in the design of gas distribution networks of cities, other settlements and distribution networks of industrial enterprises

scholarly journals Hydroxychloroquine and COVID-19

2020 ◽  
Vol 96 (1139) ◽  
pp. 550-555 ◽  
Author(s):  
Neeraj Sinha ◽  
Galit Balayla
Keyword(s):  
Lupus Erythematosus ◽  
In Vivo Studies ◽  
Respiratory Syndrome Virus ◽  
Point Of Interest ◽  
Antiviral Effects ◽  
Long Time ◽  
Novel Coronavirus ◽  
Potential Use

Hydroxychloroquine and chloroquine are medications that have been used for a long time. Their most common use is for the treatment and prophylaxis of malaria. However, these antimalarial drugs are known to also have anti-inflammatory and antiviral effects and are used for several chronic diseases such as systemic lupus erythematosus with low adverse effects. The antiviral action of hydroxychloroquine and chloroquine has been a point of interest to different researchers due to its mechanism of action. Several in vitro studies have proven their effectiveness on severe acute respiratory syndrome virus and currently both in vitro and in vivo studies have been conducted on 2019 novel coronavirus (covid-19). The purpose of this article is to review the history and mechanism of actions of these drugs and the potential use they can have on the current covid-19 pandemic.

scholarly journals Evaluation of Compilers’ Capability of Automatic Vectorization Based on Source Code Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jing Ge Feng ◽  
Ye Ping He ◽  
Qiu Ming Tao
Keyword(s):  
Compiler Optimization ◽  
Source Code ◽  
Academic Research ◽  
Engineering Practice ◽  
Source Code Analysis ◽  
Code Analysis ◽  
Multiple Data ◽  
Program Characteristics ◽  
Transformation Methods ◽  
Compiler Techniques

Automatic vectorization is an important technique for compilers to improve the parallelism of programs. With the widespread usage of SIMD (Single Instruction Multiple Data) extensions in modern processors, automatic vectorization has become a hot topic in the research of compiler techniques. Accurately evaluating the effectiveness of automatic vectorization in typical compilers is quite valuable for compiler optimization and design. This paper evaluates the effectiveness of automatic vectorization, analyzes the limitation of automatic vectorization and the main causes, and improves the automatic vectorization technology. This paper firstly classifies the programs by two main factors: program characteristics and transformation methods. Then, it evaluates the effectiveness of automatic vectorization in three well-known compilers (GCC, LLVM, and ICC, including their multiple versions in recent 5 years) through TSVC (Test Suite for Vectorizing Compilers) benchmark. Furthermore, this paper analyzes the limitation of automatic vectorization based on source code analysis, and introduces the differences between academic research and engineering practice in automatic vectorization and the main causes, Finally, it gives some suggestions as to how to improve automatic vectorization capability.

scholarly journals On Unfolding for Programs Using Strings as a Data Type

10.29007/m8rr ◽  
2018 ◽  
Author(s):  
Andrei Nemytykh
Keyword(s):  
Programming Languages ◽  
Term Rewriting ◽  
Computation Model ◽  
Abstract Machine ◽  
Rewriting Systems ◽  
Word Equation ◽  
Semantic Tree ◽  
Long Time ◽  
One Step ◽  
Transformation Methods

As a rule, program transformation methods based on semantics unfolda semantic tree of a given program. Sometimes that allows to optimize the program or to prove its certain properties automatically.Unfolding is one of the basic operations, which is a meta-extension of one step of the abstract machine executing the program.This paper is interested in unfolding for programs based on pattern matching and manipulating the strings. The corresponding computation model originates from Markov's normal algorithms and extends this theoretical base.Even though algorithms unfolding programs were being intensively studied for a long time in the context of variety of programming languages, as far as we know, the associative concatenation was stood at the wayside of the stream.We define a class of term rewriting systems manipulating with strings anddescribe an algorithm unfolding the programs from the class. The programming language defined by this class is algorithmic complete.Given a word equation, one of the algorithms suggested in this paper results in a description of the corresponding solution set.

scholarly journals Heat Transfer in Biological Spherical Tissues during Hyperthermia of Magnetoma

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1259
Author(s):  
Mahmoud Ragab ◽  
Ahmed E. Abouelregal ◽  
Huda F. AlShaibi ◽  
Rasha A. Mansouri
Keyword(s):  
Heat Transfer ◽  
Blood Perfusion ◽  
Biological Tissues ◽  
Numerical Results ◽  
Skin Tumor ◽  
Conduction Equation ◽  
Inverse Transformation ◽  
Suggested Model ◽  
Hyperthermia Treatment ◽  
Transformation Methods

Hyperthermia therapy is now being used to treat cancer. However, understanding the pattern of temperature increase in biological tissues during hyperthermia treatment is essential. In recent years, many physicians and engineers have studied the use of computational and mathematical models of heat transfer in biological systems. The rapid progress in computing technology has intrigued many researchers. Many medical procedures also use engineering techniques and mathematical modeling to ensure their safety and assess the risks involved. One such model is the modified Pennes bioheat conduction equation. This paper provides an analytical solution to the modified Pennes bioheat conduction equation with a single relaxation time by incorporating in it the (MGT) equation. The suggested model examines heat transport in biological tissues as forming an infinite concentric spherical region during magnetic fluid hyperthermia. To investigate thermal reactions caused by temperature shock, specifically the influence of heat generation through heat treatment on a skin tumor [AEGP9], the Laplace transformation, and numerical inverse transformation methods are used. This model was able to explain the effects of different therapeutic approaches such as cryotherapy sessions, laser therapy, and physical occurrences, transfer, metabolism support, and blood perfusion. Comparison of the numerical results of the suggested model with those in the literature confirmed the validity of the model’s numerical results.

scholarly journals The Role of Geotechnical Monitoring at Design of Foundation Structures and their Verification – Part 1

2016 ◽  
Vol 12 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Marián Drusa ◽  
Jozef Vlček ◽  
Lucia Orininová
Keyword(s):  
Limit State ◽  
Accurate Determination ◽  
Engineering Practice ◽  
Limit States ◽  
Foundation Soil ◽  
Geotechnical Parameters ◽  
Monte Carlo Simulation Technique ◽  
Geotechnical Monitoring ◽  
Long Time ◽  
The Cost

Abstract For a long time, design of the square foundations has not posed a problem in engineering practice. Foundations are designed on the basis of determining the bearing capacity of the subsoil, where irregularities in its determination oftentimes affect the efficiency (economy), while possible failures of bearing resistance of foundation soil are rare. More important factor is the resulting deformation of second limit state under consideration - settlement, relative settlement, tilting and excessive deformation. The current pressure on the cost reduction of design preparation and obtaining important data from geotechnical survey often results in many cases into adverse effects of settlement and differential settlement of foundations of the buildings. The question lies in a variety of analytical methods for assessing the service ability of limit states used in European countries as well as the underestimation of the proposal risks. Authors of the article want to document the fact that the most important influence on adequate and safe design is the most accurate determination of geotechnical parameters and the appropriate selection of the calculation method. For the purposes of explanation, Monte Carlo simulation technique was used to test a variety of geotechnical parameters, which will be presented in second part of article. If all construction processes are carried out successfully, rarely are the buildings evaluated once again. However, when the opportunity to participate in the stage of engineering survey and collection of geotechnical parameters as well as the control of the construction process by tools of geotechnical monitoring presents itself, it is valuable to perform the analysis of the entire process for pointing out hidden risks.

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