Modified Hybrid Method Research Articles

A Modified Hybrid Method For Solving Non-Linear Equations With Computational Efficiency

This paper proposes a modified hybrid method for solving non-linear equations that improves computational efficiency while maintaining accuracy. The proposed method combines the advantages of the traditional Halley’s and mean-based methods, resulting in a more efficient algorithm. The modified hybrid method starts with Halley’s method and then switches to the mean-based method for rapid convergence. To further improve the efficiency of the algorithm, the proposed method incorporates a dynamic selection criterion to choose the appropriate method at each iteration. Numerical experiments are performed to evaluate the performance of the proposed method in comparison to other existing methods. The results show that the modified hybrid method is computationally efficient and can achieve high accuracy in a shorter time than other commonly used methods having similar features. The proposed method is applicable to a wide range of non-linear equations and can be used in various fields of science and engineering where non-linear equations arise. The modified hybrid method provides an effective tool for solving non-linear equations, offering significant improvements in computational efficiency over existing methods.

A Modified Hybrid Method Based on PSO, GA, and K-Means for Network Anomaly Detection

Data anomaly detection plays a vital role in protecting network security and developing network technology. Aiming at the detection problems of large data volume, complex information, and difficult identification, this paper constructs a modified hybrid anomaly detection (MHAD) method based on the K-means clustering algorithm, particle swarm optimization, and genetic algorithm. First, by designing coding rules and fitness functions, the multiattribute data is effectively clustered, and the inheritance of good attributes is guaranteed. Second, by applying selection, crossover, and mutation operators to particle position and velocity updates, local optima problems are avoided and population diversity is ensured. Finally, the Fisher score expression for data attribute extraction is constructed, which reduces the required sample size and improves the detection efficiency. The experimental results show that the MHAD method has better performance than the K-means clustering algorithm, the support vector machine, decision trees, and other methods in the four indicators of recall, precision, prediction accuracy, and F-measure. The main advantages of the proposed method are that it achieves a balance between global and local search and ensures a high detection rate and a low false positive rate.

Improvement of spectrum sensing performance in cognitive radio using modified hybrid sensing method

Cognitive radio (CR) is a wireless technology for increasing the bandwidth usage. Spectrum sensing (SS) is the first step in CR. There are three basic techniques in SS, energy detection (ED), matched filter (MF), and cyclostationary detection (CFD). These techniques have many challenges in performance detection (Pd) and computational complexity (CC). In this paper, we propose a hybrid sensing method that consists of MF and CFD to exploit their merits and overcome their challenges. The proposed method aims to improve Pd and reduce CC. When MF hasn’t had enough information about PU, it switches to CFD with a reduction of CC in both MF and CFD. The proposed method is simulated under fading with cooperative and non-cooperative scenarios, measured using Pd and CC ratio Cratio, and evaluated by comparing it with traditional and hybrid methods in the literature. The simulation results show that the proposed method outperforms other methods in Pd and Cratio. For example, at Eb/No equal to 0 dB under the Rayleigh fading channel, the Pd in the proposed method increased by 38 %, 28 %, 28 %, and 18 % as compared with the modified hybrid method, traditional hybrid method, traditional CFD method, and traditional MF method in the literature, respectively.

Qualitative analysis of a discrete-time phytoplankton\u2013zooplankton model with Holling type-II response and toxicity

The interaction among phytoplankton and zooplankton is one of the most important processes in ecology. Discrete-time mathematical models are commonly used for describing the dynamical properties of phytoplankton and zooplankton interaction with nonoverlapping generations. In such type of generations a new age group swaps the older group after regular intervals of time. Keeping in observation the dynamical reliability for continuous-time mathematical models, we convert a continuous-time phytoplankton–zooplankton model into its discrete-time counterpart by applying a dynamically consistent nonstandard difference scheme. Moreover, we discuss boundedness conditions for every solution and prove the existence of a unique positive equilibrium point. We discuss the local stability of obtained system about all its equilibrium points and show the existence of Neimark–Sacker bifurcation about unique positive equilibrium under some mathematical conditions. To control the Neimark–Sacker bifurcation, we apply a generalized hybrid control technique. For explanation of our theoretical results and to compare the dynamics of obtained discrete-time model with its continuous counterpart, we provide some motivating numerical examples. Moreover, from numerical study we can see that the obtained system and its continuous-time counterpart are stable for the same values of parameters, and they are unstable for the same parametric values. Hence the dynamical consistency of our obtained system can be seen from numerical study. Finally, we compare the modified hybrid method with old hybrid method at the end of the paper.

Human Reliability Analysis for Cardiopulmonary Resuscitation Process in Emergency Medicine Using a Modified Hybrid Method Based on the Markov Model and Fault Tree Analysis

Introduction:In emergency departments (ED), human reliability assessment is essential for improving the quality of treatment and preventing medical accidents. A medical accident is expressed as an injury to a patient caused by the negligence of a doctor or nurse who is providing medical care. This study aimed to assess the human reliability in the cardiopulmonary resuscitation (CPR) process and recommend some comments to minimize human errors and improve patient safety.Materials and Methods: The main factors in the CPR process (such as rate and depth of chest compression and rate of ventilation) are identified based on the American heart association (AHA) roles. Data were recorded during three months in the evening shifts in the ED and CPR room of Imam Reza Hospital in Mashhad, Iran. In total, 42 samples were collected, and a modified hybrid approach according to the fault tree analysis and Markov method was proposed for the analysis of CPR team (including emergency medicine, medical interns, and nurses) reliability in the resuscitation process. Finally, the important basic events (errors) were selected using the Boruta algorithm by R software.Results: An FTA-Markov-based hybrid method is considered to compute the human reliability in the CPR process. The obtained results from human reliability analysis using the sensitivity analysis via Boruta algorithm and the proposed hybrid method show that an interrupt between chest compression process for rhythm control, the cycle of CPR, the depth of chest compression, and the discussion about reversible causes are the most effective factors in the human reliability of CPR process.Conclusion:The human reliability of the CPR process in the ED has been assessed using a hybrid method based on the FTA and Markov method for the first time. To improve the quality of treatment and prevent medical accidents during the CPR process, the main factors in the process are identified, and then, the proposed hybrid method is used to calculate human reliability.

Modified Hybrid Method with Four Stages for Second Order Ordinary Differential Equations

A modified explicit hybrid method with four stages is presented, with the first stage exactly integrating exp(wx), while the remaining stages exactly integrate sin(wx) and cos(wx). Special attention is paid to the phase properties of the method during the process of parameter selection. Numerical comparisons of the proposed and existing hybrid methods for several second-order problems show that the proposed method gives high accuracy in solving the Duffing equation and Kramarz’s system.

Research on MPPT Based on Gray Wolf Algorithm improved by Levy Flight

In the late iteration of the gray wolf algorithm, the convergence results will have low accuracy becased of the elite retention.When implementing MPPT control, the maximum power point of the photovoltaic array cannot be accurately tracked, and it is easy to fall into the local optimum. Therefore, this paper proposes gray wolf algorithm improved with Levy flight applied to MPPT control. The algorithm introduces the Levy flight to search the head wolf position globally, then uses the group optimization of the gray wolf algorithm and the random walk of Levy flight to improve the tracking speed and accuracy of the MPPT controller. In the simulation experiment, the algorithm is modeled and verified by setting different lighting conditions. Finally, it is compared with the conductance increment method, modified hybrid method of grey wolf optimization and golden-section optimization, the original gray wolf algorithm. The results show that the algorithm meets the requirements of fast tracking speed, high accuracy and stability in MPPT control.

Inverse design of an irregular-shaped radiant furnace using neural network and a modified hybrid optimization algorithm

In this study, the inverse solution technique is applied to design a three-dimensional heating furnace where radiation is the dominant part of heat transfer. The heat transfer mechanism is fully radiative and the furnace medium is non-gray with a mixture of 71.2% N2, 17.7% CO2, and 11.1% H2O. The design parameters include the temperature and location of the two heaters as well as the location of the design body. For the purpose of estimation of the design parameters to achieve a desired uniform heat flux at the design body, the inverse problem is considered as an optimization problem. The discrete ordinate method (DOM) is used to solve the radiation heat transfer equation (RTE) and non-gray calculations are performed by the spectral line based on the weighted-sum-of-gray-gases (WSGG) model. Additionally, the updated coefficients of the high-temperature spectral databases (HITEMP2010) are applied for non-gray gases. This study employs a modified hybrid method based on the artificial neural network (ANN) and genetic algorithm (GA) coupled with sequential quadratic programming (SQP) to optimize design parameters. In the present work, the results of three optimization algorithms including GA alone, ordinary GA-SQP and a modified form of GA-SQP are compared to find the best method to optimize the furnace problem. The final optimization results demonstrate a negligible difference between the optimized and the desired heat flux which is less than one percent. The consequences prove that the modified form of the GA-SQP algorithm (present work) is faster than others.

A modified hybrid method for a reliability-based design optimization applied to an offshore wind turbine

In this article, a dynamic analysis of an offshore wind turbine (OWT) considering soil structure interaction (SSI) is performed. The design of these highly expensive structures tends to find the best compromise between cost and safety. To do so, a coupling between reliability-based design optimization and the numerical model of the OWT is required. An extension of some RBDO methods such as the optimum safety factor, hybrid method, and the robust hybrid method in the case of an OWT considering SSI is then proposed. Results show that these techniques lead to an optimal configuration in the unsafe zone. For this, a modified hybrid method (MHM) is developed in order to overcome the drawback of the other methods. By comparing it results to the classical ones, the advantages and the efficiency of the MHM is then presented.

Parallel modified methods for pseudomonotone equilibrium problems and fixed point problems for quasi-nonexpansive mappings

The paper considers the problem of finding common solutions of a system of pseudomonotone equilibrium problems and fixed point problems for quasi-nonexpansive mappings. The problem covers various mathematical models of convex feasibility problems and the problems whose constraints are expressed by the intersection of fixed point sets of mappings. The main purpose of the paper is to design and improve computations over each step and weaken several assumptions imposed on bifunctions and mappings. Two parallel algorithms for finding of a particular solution of the problem are proposed in Hilbert spaces where each subproblem in the family can be computed simultaneously. The first one is a modified hybrid method which combines three methods including the generalized gradient-like projection method, the Mann’s iteration and the hybrid (outer approximation) method. This algorithm improves the hybrid extragradient method at each computational step where only one optimization problem is solved for each equilibrium subproblem in the family and the hybrid step does not deal with the feasible set of the considered problem. The strong convergence of the algorithm comes from the hybrid method under the Lipschitz-type condition of bifunctions. The second algorithm is a viscosity-like method with a linesearch procedure that aims to avoid the Lipschitz-type condition imposed on bifunctions. With the incorporated viscosity technique, the algorithm also provides strong convergence. Several numerical experiments are performed to illustrate the efficiency of the proposed algorithms and also to compare them with known parallel hybrid extragradient methods.

Using the hybrid DAS-SR method for damage localization in composite plates

In this paper, the hybrid Delay-And-Sum (DAS) with Sparse Reconstruction (SR) method was further developed for damage location in composite plates. In composite materials, anisotropy leads to some challenges in using conventional damage location methods, which are developed for isotropic materials. In the hybrid DAS-SR method, the DAS and SR methods were combined as a complement of each other. To investigate the DAS-SR method for composite structures, the group velocity of the travelling wave for different directions was first measured experimentally via PZTs. The DAS and SR formulations were then modified to be compatible with the direction-dependent group velocities. The results show that this modification increases the accuracy of the DAS and SR methods for damage location in a composite plate. However, using group-velocity instead of phase-velocity in the standard SR method, causes some model mismatch and errors in the damage localization and this problem was solved by using the modified hybrid DAS-SR method. The experimental results demonstrated that the performance of the modified hybrid method for detection and location of barely visible impact damages as well as for multi-location artificial damages is better than that of the DAS and SR methods when separately used.

Using cryo-electron microscopy maps for X-ray structure determination of homologues.

The combination of cryo-electron microscopy (cryo-EM) and X-ray crystallography reflects an important trend in structural biology. In a previously published study, a hybrid method for the determination of X-ray structures using initial phases provided by the corresponding parts of cryo-EM maps was presented. However, if the target structure of X-ray crystallography is not identical but homologous to the corresponding molecular model of the cryo-EM map, then the decrease in the accuracy of the starting phases makes the whole process more difficult. Here, a modified hybrid method is presented to handle such cases. The whole process includes three steps: cryo-EM map replacement, phase extension by NCS averaging and dual-space iterative model building. When the resolution gap between the cryo-EM and X-ray crystallographic data is large and the sequence identity is low, an intermediate stage of model building is necessary. Six test cases have been studied with sequence identity between the corresponding molecules in the cryo-EM and X-ray structures ranging from 34 to 52% and with sequence similarity ranging from 86 to 91%. This hybrid method consistently produced models with reasonable Rwork and Rfree values which agree well with the previously determined X-ray structures for all test cases, thus indicating the general applicability of the method for X-ray structure determination of homologues using cryo-EM maps as a starting point.

A comparative advanced exergy analysis for a solid oxide fuel cell using the engineering and modified hybrid methods

A modified form of hybrid method for advanced exergy analysis is introduced and applied to an anode gas recirculation solid oxide fuel cell system. The results are compared with the corresponding values achieved from applying the well-known engineering method of advanced exergy analysis to the system. The modified hybrid method proved to be accurate and less time consuming and also, in contrast with the hybrid method introduced in literature, doesn’t require the violation of the conservation of mass or exergy balance. In addition the modified hybrid method is more appropriate for parametric studies and optimization of energy conversion systems. The results obtained from both the advanced exergy methods are found to agree with one another and differ from those obtained from conventional exergy analysis. The values of endogenous and unavoidable endogenous exergy destruction rates for modified hybrid method are approximately 4% higher than the corresponding values obtained by the engineering method. The unavoidable conditions required for the analyses in both methods are obtained by a micro-structure analysis showing that the energy and exergy efficiencies of the system, under unavoidable conditions can be higher by up to 26%, 24.8%, respectively, compared to the corresponding values under the real conditions.As the highest avoidable endogenous exergy destruction rates occur in the inverter, 6.6 kW, and the stack, 3.7 kW, more attention should be paid to these components when the system performance is to be optimized. A different order, however, is achieved by applying the conventional exergy analysis.

Reliability Based Design Optimization for Multiaxial Fatigue Damage Analysis Using Robust Hybrid Method

AbstractThe purpose of the Reliability-Based Design Optimization (RBDO) is to find the best compromise between safety and cost. Therefore, several methods, such as the Hybrid Method (HM) and the Optimum Safety Factor (OSF) method, are developed to achieve this purpose. However, these methods have been applied only on static cases and some special dynamic ones. But, in real mechanical applications, structures are subject to random vibrations and these vibrations can cause a fatigue damage. So, in this paper, we propose an extension of these methods in the case of structures under random vibrations and then demonstrate their efficiency. Also, a Robust Hybrid Method (RHM) is then developed to overcome the difficulties of the classical one. A numerical application is then used to present the advantages of the modified hybrid method for treating problem of structures subject to random vibration considering fatigue damage.

A modified hybrid method to estimate fracture resistance curve for pipes with a circumferential surface crack

This study presents a modified hybrid method to estimate the fracture resistance curve for pipes with a circumferential surface crack. The hybrid method combines a single experimental specimen with an extending crack and several numerical models with a stationary crack of different sizes, to calculate the fracture resistance directly from the pipe specimen. The strain energy used in estimating the fracture resistance derives from the load and crack-mouth opening displacement curve. The proposed method leads to good agreement in the estimated fracture resistance curves with those based on the unloading-compliance eta-approach, for both fracture specimens and for circumferentially surface-cracked pipes.

A modified hybrid method for solving variational inequality problems in Banach spaces

A modified hybrid method for solving variational inequality problems in Banach spaces

New potentials for multiscale simulations of liquid metals

We present the technique and results for finding norm-conserving pseudopotentials and EAM potentials that can be used to recover atomic and electronic structure of liquid iron at and above the melting point. Pseudopotentials were found by minimizing the energy differences of our results with all-electron reference methods; EAM potentials — by the modified hybridization method proposed earlier by Belashchenko. We show that these potentials are at least as accurate in describing liquid iron as the established potentials in the field.

Retracted Article: Strong convergence theorem by a new iterative method for equilibrium problems and symmetric generalized hybrid mappings

In this paper, we prove a strong convergence theorem for finding a common element of the set of solutions of an equilibrium problem and the set of fixed points of a symmetric generalized hybrid mapping by using modified hybrid method. Our results extend and improve some existing results in the literature.

Mapping High-Resolution Surface Shortwave Net Radiation From Landsat Data

Maps of high-resolution surface shortwave net radiation (SSNR) are important for resolving differences in the surface energy budget at the ecosystem level. The maps can also bridge the gap between existing coarse-resolution SSNR products and point-based field measurements. This study presents a modified hybrid method to estimate both instantaneous and daily SSNR from Landsat data. SSNR values are directly linked to Landsat top-of-atmosphere reflectance by extensive radiative transfer simulation. Regression coefficients are pre-calculated and stored in a look-up table (LUT). Atmospheric water vapor is a key parameter affecting SSNR, and three methods of treating water vapor are evaluated in this study. Comparison between Landsat retrievals and field measurements at six AmeriFlux sites shows that the hybrid method with water vapor as a dimension of LUT can estimate SSNR with a root mean square error of 77.5 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (instantaneous) and 36.1 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (daily). The method of water vapor correction produces similar results. However, a generic LUT that covers all levels of water vapor results in much larger errors.

Evaluation of dosimetry and excess seeds in permanent brachytherapy using a modified hybrid method: a single-institution experience

Permanent prostate brachytherapy is frequently performed worldwide, and many studies have demonstrated its favorable outcomes. Implant seeds used in this procedure contain a precise amount of radionuclide and are completely sealed. Because these seeds are not manufactured in Japan, they are expensive (6300 yen per seed) and therefore need careful management as a radioisotope. The proper implantation technique requires considerable procedure time, good dosimetric outcomes and simple radioactive isotope management. To evaluate the modified hybrid interactive technique based on these considerations, we assessed 313 patients who underwent hybrid interactive brachytherapy without additional external beam radiotherapy. We evaluated the duration of the procedure, dosimetric factors and the total number of excess seeds. The dosimetric results from computed tomography on Day 30 of follow-up were: 172 Gy (range 130–194 Gy) for pD90, 97.8% (83.5–100%) for pV100, 54.6% (27.5–82.4%) for pV150, 164 Gy (120–220 Gy) for uD90, 194 Gy (126–245 Gy) for uD30, 210 Gy (156–290 Gy) for uD5, 0.02 ml (0–1.2 ml) for rV100 and 0 ml (0–0.2 ml) for rV150. The number of excess seeds was determined by subtracting the number of implanted seeds from the expected number of seeds calculated from previously proposed nomograms. As per our method, nine excess seeds were used for two patients, whereas using the nomograms, the number of excess seeds was approximately eight per patient. Our modified hybrid interactive technique reduced the number of excess seeds while maintaining treatment quality.