Linear Generator Research Articles

Analysis of pseudo-random number generators in QMC-SSE method

In the quantum Monte Carlo (QMC) method, the pseudo-random number generator (PRNG) plays a crucial role in determining the computation time. However, the hidden structure of the PRNG may lead to serious issues such as the breakdown of the Markov process. Here, we systematically analyze the performance of different PRNGs on the widely used QMC method known as the stochastic series expansion (SSE) algorithm. To quantitatively compare them, we introduce a quantity called QMC efficiency that can effectively reflect the efficiency of the algorithms. After testing several representative observables of the Heisenberg model in one and two dimensions, we recommend the linear congruential generator as the best choice of PRNG. Our work not only helps improve the performance of the SSE method but also sheds light on the other Markov-chain-based numerical algorithms.

Design of S-box multi-objective optimization algorithm based on combined chaotic system

S-box is the only nonlinear cryptographic component that determines the security of the block cipher. The higher the security of the S-box, the higher the security of the block cipher. Therefore, this paper proposes an S-box multi-objective optimization algorithm based on the combined chaotic system. Firstly, designing an integrated chaotic system based on a fractional index and its dynamic behavior is studied; it shows incredibly high-performance stability and chaotic parameter range coverage in the entire parameter space. A novel chaotic S-box construction algorithm is proposed based on the combined chaotic system. It introduces a linear congruential pseudo-random number generator to extend the sequence period and scramble the chaotic S-box through Henon mapping to improve the nonlinearity of the s-box. Finally, introducing a teaching and learning multi-objective optimization model and the performance evaluation criteria of the S-box are incorporated into the design of the objective function; this design enables the resulting S-box to perform well under multiple performance indicators, and then the approximate optimal S-box in the population is obtained. Through the performance test of the approximate optimal S-box, the comparative analysis shows that the S-box has good cryptographic performance, can resist linear analysis and differential analysis, and has a good application prospect in lightweight cipher.

On a Vernam cipher scheme based on elliptic curve L-functions

In this paper, we present a new Vernam-like cryptosystem based on the L-functions attached to elliptic curves. Actually, we show that for infinitely many elliptic curves, the coefficients of the L-series can be considered as a secure cryptographic cipher key when combined with linear and classical pseudo-random number generators. Hence, fast and widely known classical generators, like linear congruential generators, should be reintroduced into our list of cryptographic design choices.

Multilanguage Software License Key Generator: Accented Characters Approach

License key generator is an ideal program use to protect proprietary application against unauthorized access. From findings, the existing license key generator only support English speaking countries, which limits the participation of other language character sets. These Nonlatin sets are called accented characters which are important elements in both written and spoken language while their use in English is greatly confined to proper words borrowed from certain countries. However; this research enhances the existing license key algorithm through the use of accented characters which support multiple languages. In other to enhance the key generator, the existing data set were updated with accented characters using C# language. Advance Encryption Standard (AES) symmetric was used to secure the generated key at the cache level while linear congruential generator algorithm was used to generate the characters in a random format. Eureqa, an automated machine learning model was used to generate an equation that checks for the vulnerability, accuracy of the key generator. Therefore, the developed license key is more secure compare to the existing algorithm. Also, it support Multilanguage software key which improves the performance and allows more participation in its use. Hence, this developed system is useful for Non-English speaking countries, which provides more security through the encryption method.

Comparative Analysis of Pseudorandom Number Generators: Mersenne Twister, Middle Square Method, and Linear Congruential Generator through Dieharder Tests

Comparative Analysis of Pseudorandom Number Generators: Mersenne Twister, Middle Square Method, and Linear Congruential Generator through Dieharder Tests

Utilizing a pseudo-random Linear Congruential Generator (LCG) S-Box for encoding color images through genetic crossover

This article introduces a novel algorithm crafted for encrypting color images. The algorithm leverages chaotic principles and harnesses fresh substitution tables derived from independent linear congruence generators. These generators are dynamically sized based on pseudo-random vectors used in this technology. The proposed method initiates with the original image, vectorization, employing selected chaotic maps. The primary goal revolves around implementing a genetic operator tailored for image encryption, who integrates an enhanced Vigenère technique, incorporating novel confusion and diffusion functions derived from the previously established substitution tables. To gauge the effectiveness of this approach, numerous color images of varying dimensions and formats underwent testing using our algorithm. The yielded outcomes are both promising and gratifying, furnishing heightened security against recognized attacks.

Linear generator for power supply to on-board consumers of high-speed magnetically levitated carriages

Background: Maglev transport is a promising mode of transport that can provide passenger and freight transportation at speeds of up to 400-500 km/h, and in the longer term – up to 1000 km/h. Active research in this area is being conducted in China, Japan, and the USA. Currently, in China and Japan, speeds of 450-500 km/h have been achieved for commercial transportation, and promising programs have been adopted for the construction of high-speed maglev tracks and the creation of rolling stock. At such speeds, one of the pressing problems is the problem of contactless energy transfer for on-board consumers located on the carriage, because it is very difficult to ensure reliable contact current collection at speeds of 450-500 km/h and above.
 Aim: development of the design, calculation and analysis of the characteristics of a linear generator of electrical energy for contactless power transfer to the moving crew of high-speed magnetically levitated transport.
 Materials and methods: to calculate the external magnetic field of the linear generator inductor and the EMF induced in the receiving coil of the crew, methods of electromagnetic field theory and electrical circuit theory were used; calculation algorithms are implemented in the Visual Basic for Applications software environment.
 Results: a design was proposed and the calculation of the external magnetic field of an inductor with transposition of conductors was performed; to increase the EMF induced in the receiving coil of the crew, it is proposed to give the receiving coil a double 8-shape; the most rational inter-circuit distance of the linear generator inductor has been established; the nature of the change in the magnetic flux penetrating the receiving coil when the vehicle moves, and the magnitude of the emf induced in the receiving coil are determined.
 Conclusion: the results can be used in the development of rolling stock for promising high-speed maglev transport systems.

An Adaptive Fractal Image Steganography Using Mandelbrot and Linear Congruent Generator

Despite the advancements that occurred in the field of technology, information security (i.e., IS) is still deemed important and critical topic. It is still especially deemed so during the transfer process. In this research, a new approach is proposed for hiding information through the use of iterated function systems (i.e., IFS) from Fractals. This approach employs the main feature of fractals that concentrate on the idea that hackers who seek to find the hidden data shall not be able of locating it. Therefore, there is a need to carry out a decoding process in the aim of revering the conversion for securing the transmitted information. In this research, the secure information is hidden inside a fractal Mandelbrot image using the Linear Congruent Generator (i.e., LCG). Regarding the proposed system, it generates the fractal image through the use of the predefined knowledge gained from the hider site that works as a host for different types of secret messages. The knowledge that comes from the key of image dimensions, parameters of Mandelbrot, LCG key, and key agreement of cryptography method, which makes Stego-image analyses of hidden data unacceptable without the correct knowledge. Based on the results that are obtained through carrying out experiments showed the proposed method meets all the requirements for steganography. Such requirements include: the ones related to capacity, visual appearance, undetectability, robustness against extraction (i.e., security), and hit the highest capacities with a visual appearance of high quality.

Operation characteristic research on organic Rankine cycle-free piston linear generator (ORC-FPLG) based on multi-module combination

Free piston linear generator (FPLG) presents great potential in organic Rankine cycle (ORC) system to replace traditional expanders because of low friction loss, simple structure and good sealing. Drawing on the concept of multi-cylinder engines, ORC-FPLG simulation model coupled with vehicle have been established based on multi-module combination with GT-suite/Simulink. Then, the operation characteristics in parallel mode, series mode and different intake distribution modes are analyzed. And the influence of engine parameters, and the energy-saving potential under road conditions are explored. The results show that: there exists an optimal module number in parallel mode to maximize net output power and thermal efficiency. When the number of modules is 4, the maximum net output power and thermal efficiency are 11.19 kW and 7.73%. The more parallel modules in series mode is, the higher net output power and thermal efficiency is, which is more conducive to improve output performance. Net power output and thermal efficiency gradually increase with engine speed and fuel injection. There exists an optimal injection timing and exhaust timing to maximize net power output and thermal efficiency. Compared to urban road conditions, ORC-FPLG system under suburban conditions achieves better energy recovery results with waste heat recovery efficiency of 2.22%.

Master generators: A novel approach to construct and solve ordinary differential equations

Ordinary differential equations (ODEs) play a crucial role in applied mathematics, engineering, and various other fields. With a rich history of study and countless applications, they have attracted the attention of researchers who have developed numerous methods for solving linear and non-linear ODEs. However, despite considerable progress, there remain many unsolved equations and challenges in finding appropriate solutions. This research introduces a groundbreaking method for generating an infinite number of generators for both linear and non-linear ODEs, based on the use of master improper integrals and a set of novel theorems. The proposed method enables the creation of infinite ODEs using a single generator, providing a versatile and powerful approach to tackling various types of differential equations. This research not only presents several specific generators derived from the theorems, but also establishes general forms for linear and non-linear generators, highlighting their adaptability to a wide range of scenarios. In addition, we demonstrate the practical utility of the generators through real-world examples and applications across diverse fields such as quantum field theory, astrophysics, and fluid dynamics. These examples showcase the potential of the proposed method in solving complex problems and its far-reaching impact on multiple disciplines. Through a comprehensive presentation of the theoretical underpinnings, derivation of generators, and application examples, this research aims to provide a thorough understanding of the infinite generators for linear and non-linear ODEs, as well as to inspire further research and development in this fascinating and vital area of applied mathematics. The introduction of infinite generators not only addresses the existing challenges in solving ODEs but also opens up new avenues for exploring novel solutions and approaches, ultimately contributing to the advancement of various fields that rely on differential equations.

A Study on the Safety by Thermal Characteristics of Tubular Linear Generator for Bladeless Wind Power Generation System

A Study on the Safety by Thermal Characteristics of Tubular Linear Generator for Bladeless Wind Power Generation System

Retracted: Analysis of the Characteristics in Linear Generator for EDS Maglev Based on Harmonic Magnetic Field Method

The optimal non-contact onboard power source for superconducting electrodynamics suspension (EDS) maglev is the linear generator. As a result, the development of the linear generator has been significantly aided by the research of its properties. A method for figuring out the maximum output power of the EDS maglev's linear generator is suggested. It has the advantages of a straightforward formulation, quick calculation time, and acceptable precision. First, the electromagnetic model of the linear generator taking into account the eddy current loss of the outer vessel is constructed in accordance with the structure of EDS maglev. Second, the magnetic flux density of superconducting (SC) coils and the multi-structure figure-8 shaped coils containing harmonic components are expressed using Fourier coefficients utilizing the harmonic magnetic field approach, and this is done by incorporating the structural correction coefficient of SC coils. Third, it is proposed to use variable resistance to equivalent eddy current losses to calculate the linear generator's maximum output power. Finally, the finite element (FEM) simulation and the measurement data of the Yamanashi line are used to confirm that the theory is valid.

Analysis of linear congruent methods and multiplicative random number generator in computer-based test

This research focuses on the implementation of computer - based test exams in high schools which face the problem of not having differences in exam questions which results in weak security and validity of exam results. Therefore, a randomization method is needed to overcome this problem. The method used in random ization is linear congruent methods and multiplicative random number generator. There are 101 random questions, but only 40 questions are displayed for each student with a reference value of Xn and C, 2 will be added for each package of exam questions and to avoid question code=0, the calculation results will be added 1. The linear congruent methods (LCM) results achieve 100% accuracy, while the method The multiplicative random number generator (MRNG) only achieved 62.5% accuracy in randomizing the exam que stions. This accuracy comparison highlights the difference in the ability of the two methods to generate random permutations of test item packages. LCM randomization accuracy ensures that each student will receive a different set of test questions in a con sistent manner. However, the low accuracy of randomization using MRNG indicates a weakness in generating permutations of exam question packages. The results of this study show that the LCM method is better than the MRNG in conducting exams.

Improvement on Thrust Control for Start-Up and Piston Motion of Free-Piston Linear Generator

Free-piston linear generators (FPLGs) without a crank mechanism are promising to be used in hybrid vehicles due to their unique operation characteristics. However, the FPLG currently still faces challenges in the start-up and piston control. In this paper, the start-up and operation process of FPLG are analyzed deeply and the improved thrust control strategies for the linear electric machine (LEM) are presented accordingly. First, the mechanism that the vibration center shifts under the general constant thrust resonance starting method is revealed, considering the asymmetric potential energy caused by non-linear compression spring effect in the combustion chamber. Then, a compensation thrust iteratively adjusted by the vibration offset is added to stabilize the swing center during start-up. Next, the coupling effect between the dead centers under single-stroke independent thrust control method is analyzed, by modeling the piston motion from the aspect of energy flow. Accordingly, an improved thrust control method for coupling suppression is presented to enhance the accuracy and robustness of piston motion. Finally, the performance of the proposed method is verified by controlling a permanent- magnet linear synchronous machine (PMLSM) in experiments and simulations.

A study of measurements and countermeasures for low-frequency noise caused by expressway bridges

Expressway bridges, though rarely, generate low-frequency noise caused by coupled bridge and road traffic vibration. This paper reports a case study on taking measurements and countermeasures of infrasound on an actual expressway bridge. First, the paper outlines a wind noise estimation method that takes into account the effect of wind and reflects the frequency, mean velocity, and turbulence intensity on the measurements of infrasound. Next, a case study on an improved TMD (Tuned Mass Damper), one method to suppress low-frequency noise, is presented. An overview of the generator-type TMD, in which the oil damper of the TMD is replaced by a linear generator, is given, and the results of a field test of its effectiveness are reported. The damping function of the generator-type TMD can be easily tuned by incorporating a variable resistance value into the generator. Through these undertakings, energy from road traffic vibration can be effectively utilized, supporting reductions in environmental impact and making a significant contribution to the SDGs of expressway projects.

Layout Optimization and Performance Analysis of Vehicle Suspension System Using an Electromagnetic Inerter

The inerter is a vibration isolation device used to replace the mass element in classical vibration isolation theory. The introduction of an inerter into a vehicle suspension system can greatly improve the performance of the system. An electromagnetic inerter is a kind of device that can realize a complex suspension structure without an additional energy supply and a complicated control system. It not only utilizes hydraulic systems to attain various suspension mechanical structures but also incorporates linear generators to form more intricate electrical networks. In this paper, an approach is proposed to achieve an optimized vehicle suspension layout using an electromagnetic inerter, which promotes the practical application of the device. First, seven suspension layouts are presented based on this device and relevant models are established to optimize the performance of these seven layouts under certain objectives. Then, the influence of three factors of the electrical network, namely linear generator internal resistance, inductance, and linear generator coefficient, on suspension performance is analyzed. At the same time, to ensure the suspension performance of this device is closer to that required for actual engineering applications, the improvement in the vibration isolation performance of the device compared with traditional passive suspension is discussed considering these three factors. The final results show that when considering the real-world situation, the L1 and L4 layouts can achieve excellent performance improvement, with RMS(BA) values of only 85.73% and 84.66% of the traditional passive suspension.

Operating characteristics and design parameter optimization of permanent magnet linear generator applied to free-piston energy converter

A tubular permanent magnet linear generator (PMLG) with axial magnetized is proposed for the free-piston engine generator (FPEG). The structures and test rigs of the PMLG and FPEG prototypes are introduced. The working characteristics of the PMLG in FPEG system are analyzed under ignition conditions. A 2D finite element model of the PMLG is designed and verified based on initial design parameters and test results. The influences of key operating parameters on the output performance of PMLG are studied. On these basis, when considering the actual motion characteristics of the PMLG in FPEG system, the effects of different structural parameters on the power generation performance and efficiency (h) are investigated. Results show that when the working frequency of the FPEG is relatively small, the displacement profile resembles a sinusoidal curve. As the working frequency and stroke length increase, the power generation increases rapidly. As the air gap length and back iron shaft diameter decrease, and the stator slot number increases, the output voltage (U), current (I), power (Pout), and total loss power (Ploss) show an approximately linear increasing trend. As the pole arc coefficient and stator tooth width increase, the U, I, Pout, and Ploss first increase and then decrease. As the stator yoke thickness increases, the U, I, and Pout increase rapidly and then tend to stabilize. Besides, these structural parameters have little impact on power generation efficiency of this PMLG.

Random Switching Period SVPWM Technique with Variable Sampling Frequency for Three‐Phase Power Converters

To improve the pulse width modulation (PWM) harmonic suppression effect of the three‐phase VSI‐fed PMSM system, this paper proposed a novel random switching period (RSP)‐Space Vector Pulse Width Modulation (SVPWM) technique for the three‐phase power converter. First, the proposed technique replaces the 10‐bit linear feedback shift register pseudorandom number generator (LFSR‐PRNG) with a Tiny Mersenne Twister (MT)‐PRNG to quickly generate high‐quality pseudorandom number sequences. Then, to reduce the sampling error caused by the current ripple, this paper analyzes the sampling timing under different modulation techniques. Based on the interrupted update mechanism of the Infineon AURIX‐TC264, the variable frequency sampling of the RSP‐SVPWM technique is implemented to ensure the best sampling of the motor phase current. Finally, the simulation and experimental results show that the proposed technique can effectively disperse PWM harmonic energy. Meanwhile, the RSP‐SVPWM technique based on variable sampling frequency effectively improves the phase current quality of the PMSM system. The proposed technique shows great potential for suppressing PWM harmonics in integrated PMSM systems. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Modeling of permanent magnet linear generator and state estimation based on sliding mode observer: A wave energy system application

Modeling of permanent magnet linear generator and state estimation based on sliding mode observer: A wave energy system application

ESTIMATION OF MACHINE TOOL ACCURACY BASED ON MONTE CARLO SIMULATION USING MOVEMENT AXES GEOMETRIC ERRORS MODEL

Accuracy is one of the most important feature of a machine tool. Being able to estimate the overall accuracy of a machine tool represented by the total volumetric error can be a huge advantage in the design process. This paper provides overview of methods used for geometric error transfer modeling and volumetric error modeling. An error transfer rigid body model is derived and after that, a random linear guideway straightness error profile generator is proposed. This allows to simulate a movement axis with random straightness errors of rails and computed geometric errors of an assembled axis. Volumetric error of a 3-axis machine tool is then modeled using its kinematic scheme and homogenous transformation matrices with 21 kinematic errors. Using simulated axes as input to the volumetric model, an entire machine tool can be simulated. From that, the total volumetric error can be obtained and a Monte Carlo simulation carried out. This allows to analyze statistics of the total volumetric error and with slight input changes (rail straightness tolerance), a sensitivity analysis can be performed to determine the most influential errors in the machine tool.