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Software Defect Prediction Using Hybrid Machine Learning Techniques: A Comparative Study
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作者 Hemant Kumar Vipin Saxena 《Journal of Software Engineering and Applications》 2024年第4期155-171,共17页
When a customer uses the software, then it is possible to occur defects that can be removed in the updated versions of the software. Hence, in the present work, a robust examination of cross-project software defect pr... When a customer uses the software, then it is possible to occur defects that can be removed in the updated versions of the software. Hence, in the present work, a robust examination of cross-project software defect prediction is elaborated through an innovative hybrid machine learning framework. The proposed technique combines an advanced deep neural network architecture with ensemble models such as Support Vector Machine (SVM), Random Forest (RF), and XGBoost. The study evaluates the performance by considering multiple software projects like CM1, JM1, KC1, and PC1 using datasets from the PROMISE Software Engineering Repository. The three hybrid models that are compared are Hybrid Model-1 (SVM, RandomForest, XGBoost, Neural Network), Hybrid Model-2 (GradientBoosting, DecisionTree, LogisticRegression, Neural Network), and Hybrid Model-3 (KNeighbors, GaussianNB, Support Vector Classification (SVC), Neural Network), and the Hybrid Model 3 surpasses the others in terms of recall, F1-score, accuracy, ROC AUC, and precision. The presented work offers valuable insights into the effectiveness of hybrid techniques for cross-project defect prediction, providing a comparative perspective on early defect identification and mitigation strategies. . 展开更多
关键词 Defect Prediction Hybrid techniques Ensemble Models Machine Learning Neural Network
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A Parallel Hybrid Testing Technique for Tri-Programming Model-Based Software Systems
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作者 Huda Basloom Mohamed Dahab +3 位作者 Abdullah Saad AL-Ghamdi Fathy Eassa Ahmed Mohammed Alghamdi Seif Haridi 《Computers, Materials & Continua》 SCIE EI 2023年第2期4501-4530,共30页
Recently,researchers have shown increasing interest in combining more than one programming model into systems running on high performance computing systems(HPCs)to achieve exascale by applying parallelism at multiple ... Recently,researchers have shown increasing interest in combining more than one programming model into systems running on high performance computing systems(HPCs)to achieve exascale by applying parallelism at multiple levels.Combining different programming paradigms,such as Message Passing Interface(MPI),Open Multiple Processing(OpenMP),and Open Accelerators(OpenACC),can increase computation speed and improve performance.During the integration of multiple models,the probability of runtime errors increases,making their detection difficult,especially in the absence of testing techniques that can detect these errors.Numerous studies have been conducted to identify these errors,but no technique exists for detecting errors in three-level programming models.Despite the increasing research that integrates the three programming models,MPI,OpenMP,and OpenACC,a testing technology to detect runtime errors,such as deadlocks and race conditions,which can arise from this integration has not been developed.Therefore,this paper begins with a definition and explanation of runtime errors that result fromintegrating the three programming models that compilers cannot detect.For the first time,this paper presents a classification of operational errors that can result from the integration of the three models.This paper also proposes a parallel hybrid testing technique for detecting runtime errors in systems built in the C++programming language that uses the triple programming models MPI,OpenMP,and OpenACC.This hybrid technology combines static technology and dynamic technology,given that some errors can be detected using static techniques,whereas others can be detected using dynamic technology.The hybrid technique can detect more errors because it combines two distinct technologies.The proposed static technology detects a wide range of error types in less time,whereas a portion of the potential errors that may or may not occur depending on the 4502 CMC,2023,vol.74,no.2 operating environment are left to the dynamic technology,which completes the validation. 展开更多
关键词 Software testing hybrid testing technique OpenACC OPENMP MPI tri-programming model exascale computing
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Enhancing rock fragmentation prediction in mining operations:A hybrid GWO-RF model with SHAP interpretability 被引量:1
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作者 ZHANG Yu-lin QIU Yin-gui +2 位作者 ARMAGHANI Danial Jahed MONJEZI Masoud ZHOU Jian 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2916-2929,共14页
In the mining industry,precise forecasting of rock fragmentation is critical for optimising blasting processes.In this study,we address the challenge of enhancing rock fragmentation assessment by developing a novel hy... In the mining industry,precise forecasting of rock fragmentation is critical for optimising blasting processes.In this study,we address the challenge of enhancing rock fragmentation assessment by developing a novel hybrid predictive model named GWO-RF.This model combines the grey wolf optimization(GWO)algorithm with the random forest(RF)technique to predict the D_(80)value,a critical parameter in evaluating rock fragmentation quality.The study is conducted using a dataset from Sarcheshmeh Copper Mine,employing six different swarm sizes for the GWO-RF hybrid model construction.The GWO-RF model’s hyperparameters are systematically optimized within established bounds,and its performance is rigorously evaluated using multiple evaluation metrics.The results show that the GWO-RF hybrid model has higher predictive skills,exceeding traditional models in terms of accuracy.Furthermore,the interpretability of the GWO-RF model is enhanced through the utilization of SHapley Additive exPlanations(SHAP)values.The insights gained from this research contribute to optimizing blasting operations and rock fragmentation outcomes in the mining industry. 展开更多
关键词 BLASTING rock fragmentation random forest grey wolf optimization hybrid tree-based technique
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Hybrid Model Testing Technique for Deep-Sea Platforms Based on Equivalent Water Depth Truncation 被引量:4
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作者 张火明 杨建民 肖龙飞 《China Ocean Engineering》 SCIE EI 2007年第3期401-416,共16页
In this paper, an inner turret moored FPSO which works in the water of 320 m depth, is selected to study the socalled "passively-truncated + numerical-simulation" type of hybrid model testing technique while the tn... In this paper, an inner turret moored FPSO which works in the water of 320 m depth, is selected to study the socalled "passively-truncated + numerical-simulation" type of hybrid model testing technique while the tnmcated water depth is 160 m and the model scale ), = 80. During the investigation, the optimization design of the equivalent-depth truncated system is performed by using the similarity of the static characteristics between the truncated system and the full depth one as the objective function. According to the truncated system, the corresponding physical test model is made. By adopting the coupling time domain simulation method, the tnmcated system model test is numerically reconstructed to carefully verify the computer simulation software and to adjust the corresponding hydrodynamic parameters. Based on the above work, the numerical extrapolation to the full depth system is performed by using the verified computer software and the adjusted hydrodyrmmic parameters. The full depth system model test is then performed in the basin and the results are compared with those from the numerical extrapolation. At last, the implementation procedure and the key technique of the hybrid model testing of the deep-sea platforms are summarized and printed. Through the above investigations, some beneficial conclusions are presented. 展开更多
关键词 hybrid model testing technique equivalent water depth truncation FPSO hydrodynamic response TURRET
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A Triple-Channel Encrypted Hybrid Fusion Technique to Improve Security of Medical Images 被引量:1
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作者 Ahmed S.Salama Mohamed Amr Mokhtar +2 位作者 Mazhar B.Tayel Esraa Eldesouky Ahmed Ali 《Computers, Materials & Continua》 SCIE EI 2021年第7期431-446,共16页
Assuring medical images protection and robustness is a compulsory necessity nowadays.In this paper,a novel technique is proposed that fuses the wavelet-induced multi-resolution decomposition of the Discrete Wavelet Tr... Assuring medical images protection and robustness is a compulsory necessity nowadays.In this paper,a novel technique is proposed that fuses the wavelet-induced multi-resolution decomposition of the Discrete Wavelet Transform(DWT)with the energy compaction of the Discrete Wavelet Transform(DCT).The multi-level Encryption-based Hybrid Fusion Technique(EbhFT)aims to achieve great advances in terms of imperceptibility and security of medical images.A DWT disintegrated sub-band of a cover image is reformed simultaneously using the DCT transform.Afterwards,a 64-bit hex key is employed to encrypt the host image as well as participate in the second key creation process to encode the watermark.Lastly,a PN-sequence key is formed along with a supplementary key in the third layer of the EbHFT.Thus,the watermarked image is generated by enclosing both keys into DWT and DCT coefficients.The fusions ability of the proposed EbHFT technique makes the best use of the distinct privileges of using both DWT and DCT methods.In order to validate the proposed technique,a standard dataset of medical images is used.Simulation results show higher performance of the visual quality(i.e.,57.65)for the watermarked forms of all types of medical images.In addition,EbHFT robustness outperforms an existing scheme tested for the same dataset in terms of Normalized Correlation(NC).Finally,extra protection for digital images from against illegal replicating and unapproved tampering using the proposed technique. 展开更多
关键词 Medical image processing digital image watermarking discrete wavelet transforms discrete cosine transform encryption image fusion hybrid fusion technique
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Combined endoscopy/laparoscopy/percutaneous transhepatic biliary drainage, hybrid techniques in gastrointestinal and biliary diseases
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作者 Yi-Long Feng Jing Li +2 位作者 Lian-Song Ye Xian-Hui Zeng Bing Hu 《World Journal of Meta-Analysis》 2020年第3期210-219,共10页
In recent years,a wide range of gastrointestinal endoscopy techniques have been developed,such as endoscopic submucosal dissection(ESD)and endoscopic retrograde cholangiopancreatography(ERCP).Although ESD and ERCP hav... In recent years,a wide range of gastrointestinal endoscopy techniques have been developed,such as endoscopic submucosal dissection(ESD)and endoscopic retrograde cholangiopancreatography(ERCP).Although ESD and ERCP have an important role in gastrointestinal and biliary diseases,each technique has its limitations.Hybrid techniques that combine endoscopic and surgical procedures have emerged that have the advantages of different procedures and negate their limitations at the same time.Laparoscopic endoscopic cooperative surgery and modified laparoscopic endoscopic cooperative surgery combine ESD and laparoscopic techniques to resect submucosal tumors with minimum resection area.Air leak test by intraoperative endoscopy can effectively identify a mechanically insufficient anastomosis and decrease the complication rate.The rendezvous technique that combines percutaneous transhepatic biliary drainage and endoscopy can be performed as a rescue approach for the treatment of biliary obstruction,stenosis and bile duct injuries.For patients with simultaneous presence of stones in the gallbladder and the common bile duct,the laparoendoscopic rendezvous technique can perform ERCP and laparoscopic cholecystectomy at the same time and reduces the risk of pancreatic injury caused by ERCP.Biliobiliary and bilioenteric anastomosis using magnetic compression anastomosis is another choice for biliary obstruction.The most common used approach to deliver the magnets is by percutaneous-peroral tract.Laparoscopicassisted ERCP is a safe and highly effective therapy for patients who develop biliary diseases after Roux-en-Y gastric bypass surgery. 展开更多
关键词 Hybrid technique Laparoscopic and endoscopic cooperative surgery Endoscopic retrograde cholangiopancreatography Laparoscopic-assisted endoscopic retrograde cholangiopancreatography Rendezvous technique Magnetic compression anastomosis
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2D Animation Hybrid Technique Combining Traditional and Digital Technique Based on Analytical Motion and Physics
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作者 Michael Sega Gumelar 《Computer Technology and Application》 2011年第4期263-269,共7页
Great Animation not just drawing sequence of images or just combining images into frame by frame whatever motion will be, but Great Animation actually based on Physics, Biology and Lip sync. 2D Animation Hybrid Techni... Great Animation not just drawing sequence of images or just combining images into frame by frame whatever motion will be, but Great Animation actually based on Physics, Biology and Lip sync. 2D Animation Hybrid Technique is combination of Traditional Technique and Digital Technique, but the motion also based on analytical motion and physics. Traditional technique using mostly stop motion technique and experiment in any material animated objects, such as celluloid, sand, pebble, clay, doll, flour, or any objects that can be animated. This day digital technique is widely used mostly using computer hardware and software, and a lot of 2D animation software out there that can be used to create 2D animation. 2D Animation Hybrid Technique is a new technique that combining the traditional 2D animation technique but not using stop motion technique and with digital technique using computer and software, this technique become possible using image scanning technology that can digitizing any image from photo to hand drawn image. Then the sequence hand drawn animation edited in frame by frame also layer by layer using certain software in computer to create illusion of motion. The motion itself not just using any sense of art but also using physics, biology especially anatomy when needed to create such realism motion or perhaps funny motion in cartoon style animation. 展开更多
关键词 2D animation hybrid technique combining traditional and digital technique.
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Study on the 3D Seismic Data Field Hybrid Rendering Technique of Natural Gas Hydrate and Its Application
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作者 Pan LI Zhaojun ZHOU Meng HUANG 《International Journal of Technology Management》 2013年第2期50-52,共3页
3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper,... 3D visualization technology is a tool used for displaying, describing, and understanding the characteristics of geologic bodies, and features high efficiency, objective accuracy, visual expression, etc. In this paper, the man-machine interactive interpretation and 3D visualization technology rapidly displaying and analyzing the 3D seismic data of hydrate ore volume is researched and developed using the hybrid rendering technique. Through the integrated interpretation on the 3D space structure, stratum, and seismic attributes, the visualized multi-attribute superimposition analysis is implemented for describing the spatial distribution characteristics of hydrate ore volume and exquisitely describing the subtle geological characteristics of hydrate ore volume. By the hybrid rendering technique, authentication and interpretation are provided for the geological exploration work, so as to greatly enhance the visualization and accuracy of the geological analysis, and also provide a good decision-making foundation for the subsequent development of resources. 展开更多
关键词 Natural Gas Hydrate 3D Seismic Data Hybrid Rendering technique
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Enhanced Electric Power Adaptability Using Hybrid Pumped-Hydro Technology with Wind and Photovoltaic Integration
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作者 Uwem O.Ikitde Abayomi A.Adebiyi +1 位作者 Innocent E.Davidson Ayodeji S.Akinyemi 《Energy Engineering》 EI 2023年第9期1939-1961,共23页
The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable characteristics.Because wind energy varies across all timescales of utility activity,... The integration of solar and wind energy into the electrical grid has received global research attention due to their unpredictable characteristics.Because wind energy varies across all timescales of utility activity,renewable energy generation should be supplemented and enhanced,from real-time,minute-to-minute variations to annual alterations influencing long-termstrategy.Wind energy generation does not only fluctuate but is also challenging to accurately forecast the timeframes of significance to electricity decision makers;day-ahead and long-term making plans of framework sufficiency such as meeting the network peak load annually.A utility that integrates wind and solar energy into its electricity mix would understand how to adapt to uncertainty and variability in operations while sustaining grid stability.Due to hydropower’s adaptability,a system using hydropower as one of its generating resources could be precisely adapted to absorb the variability of wind and solar energy.The objective of this research study is to create a hybrid system comprising hydro-wind and solar(Hybrid-HWS)integration for power balancing in an isolated electrical network in Klipkop village,Pretoria region,South Africa.The desirability of designing and building goaf storage tank in regard to capability,the fullness of line throughoutwater pumping,dispensing,storage tank spillage,and pressure difference throughout liquid flow within the storage tanks were preliminary assessed using geotechnical and weather forecasting data from a distinctive area of Klipkop town in Pretoria,South Africa.Different facility hours premised on daylight accessibility are scheduled to balance maximum load at early and late hours.However,in the scenario of electrical power,time shift requiring storage for extended periods of time,such as in terms of hours,Hybrid-HWS has been found to have a crucial role.The results of simulations showed a coordinated process design for Hybrid-HWS Energy Storage(ES)to determine everyday strategic planning in reducing the variability of the system resulting from wind-solar-pumped hydro ES output inadequacies and satisfy daily load demands.It could be recommended that by considering the adaptability characteristics,extremely rapidly,ramping,peaking support and maximum stabilizing aid of the system could be archived with pump-hydro into the energy mix which can provide specific guidelines for energy policymakers. 展开更多
关键词 Pumped hydro storage(PHS) hybrid hydro-wind-solar technique abandoned coal mine power balancing
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Hybrid Verification of A Deepwater Cell-Truss Spar 被引量:3
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作者 苏一华 杨建民 肖龙飞 《China Ocean Engineering》 SCIE EI 2009年第1期1-14,共14页
Hybrid model testing technique is widely used in verification of a deepwater floating structure and its mooring system, but the design of the truncated mooring systems which can reproduce both static and dynamic respo... Hybrid model testing technique is widely used in verification of a deepwater floating structure and its mooring system, but the design of the truncated mooring systems which can reproduce both static and dynamic response same as the full-depth mooring system is still a big challenge, especially for the mooring systems with large truncation. A Cell-Truss Spar operated in 1500 m water depth is verified in a wave basin with 4 m water depth. A large truncation factor arises even though a small model scale 1 : 100 is adopted. Computer program modules for analyzing the static and frequency domain dynamic response of mooting line are combined with multi-objective genetic algorithm NSGA-II to optimize the truncated mooring system. Considering the asyrmnetry of layout of mooring lines, two different truncated mooring systems are respectively designed for both directions in which the restoring forces of the mooring system are quite different. Not only the static characteristics of the mooring systems are calibrated, but also the dynamic responses of the single truncated mooring line are evaluated through time domain numerical simulation and model tests. The model test results of 100-year storm in the GOM are reconstructed and extrapolated to a full depth. It is found that the experimental and numerical resuits of Spar wave frequency motion agree well, and the dynamic responses of the full-depth mooring lines are better reproduced, but the low frequency surge motion is overestimated due to the smaller mooring-induced damping. It is a feasible method adopting different tnmcated mooring systems for different directions in which the restoring force characteristics are quite different and cannot be simulated by one truncated mooring system. Hybrid verification of a deepwater platform in wave basin with shallow water depth is still feasible if the truncated mooring systems are properly designed, and numerical extrapolation is necessary. 展开更多
关键词 hybrid model testing technique DEEPWATER Spar mooring system TRUNCATION
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Unsupervised neural network model optimized with evolutionary computations for solving variants of nonlinear MHD Jeffery-Hamel problem 被引量:1
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作者 M.A.Z.RAJA R.SAMAR +1 位作者 T.HAROON S.M.SHAH 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第12期1611-1638,共28页
A heuristic technique is developed for a nonlinear magnetohydrodynamics (MHD) Jeffery-Hamel problem with the help of the feed-forward artificial neural net- work (ANN) optimized with the genetic algorithm (GA) a... A heuristic technique is developed for a nonlinear magnetohydrodynamics (MHD) Jeffery-Hamel problem with the help of the feed-forward artificial neural net- work (ANN) optimized with the genetic algorithm (GA) and the sequential quadratic programming (SQP) method. The twodimensional (2D) MHD Jeffery-Hamel problem is transformed into a higher order boundary value problem (BVP) of ordinary differential equations (ODEs). The mathematical model of the transformed BVP is formulated with the ANN in an unsupervised manner. The training of the weights of the ANN is carried out with the evolutionary calculation based on the GA hybridized with the SQP method for the rapid local convergence. The proposed scheme is evaluated on the variants of the Jeffery-Hamel flow by varying the Reynold number, the Hartmann number, and the an- gles of the walls. A large number of simulations are performed with an extensive analysis to validate the accuracy, convergence, and effectiveness of the scheme. The comparison of the standard numerical solution and the analytic solution establishes the correctness of the proposed designed methodologies. 展开更多
关键词 Jeffery-Hamel problem neural network genetic algorithm (GA) nonlinear ordinary differential equation (ODE) hybrid technique sequential quadratic programming
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Numerical Simulation of PMM Tests for A Ship in Close Proximity to Sidewall and Maneuvering Stability Analysis 被引量:1
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作者 刘晗 马宁 顾解忡 《China Ocean Engineering》 SCIE EI CSCD 2016年第6期884-897,共14页
As the maneuverability of a ship navigating close to a bank is influenced by the sidewall, the assessment of ship maneuvering stability is important. The hydrodynamic derivatives measured by the planar motion mechani... As the maneuverability of a ship navigating close to a bank is influenced by the sidewall, the assessment of ship maneuvering stability is important. The hydrodynamic derivatives measured by the planar motion mechanism (PMM) test provide a way to predict the change of ship maneuverability. This paper presents a numerical simulation of PMM model tests with variant distances to a vertical bank by using unsteady RANS equations. A hybrid dynamic mesh technique is developed to realize the mesh configuration and remeshing of dynamic PMM tests when the ship is close to the bank. The proposed method is validated by comparing numerical results with results of PMM tests in a circulating water channel. The first-order hydrodynamic derivatives of the ship are analyzed from the time history of lateral force and yaw moment according to the multiple-run simulating procedure and the variations of hydrodynamic derivatives with the ship-sidewall distance are given. The straight line stability and directional stability are also discussed and stable or unstable zone of proportional-derivative (PD) controller parameters for directional stability is shown, which can be a reference for course keeping operation when sailing near a bank. 展开更多
关键词 sidewall effect numerical simulation planar motion mechanism (PMM) hybrid dynamic mesh technique ship maneuvering stability
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Efficient Approach for Resource Allocation in WPCN Using Hybrid Optimization
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作者 Richu Mary Thomas Malarvizhi Subramani 《Computers, Materials & Continua》 SCIE EI 2022年第7期1275-1291,共17页
The recent aggrandizement of radio frequency(RF)signals in wireless power transmission combined with energy harvesting methods have led to the replacement of traditional battery-powered wireless networks since the blo... The recent aggrandizement of radio frequency(RF)signals in wireless power transmission combined with energy harvesting methods have led to the replacement of traditional battery-powered wireless networks since the blooming RF technology provides energy renewal of wireless devices with the quality of service(QoS).In addition,it does not require any unnecessary alterations on the transmission hardware side.A hybridized global optimization technique uniting Global best and Local best(GL)based particle swarm optimization(PSO)and ant colony optimization(ACO)is proposed in this paper to optimally allocate resources in wireless powered communication networks(WPCN)through coordinated operation of communication groups,in which the wireless energy transfer and information sharing take place concomitantly by the aid of a cooperative relay positioned in between the communicating groups.The designed algorithm assists in minimizing power consumption and maximizes the weighted sum rate at the end-user side.Thus the principal target of the system is coordinated optimization of energy beamforming along with time and energy allocation to reduce the total energy consumed combined with assured information rates of the communication groups.Numerical outputs are presented to manifest the proposed system’s performance to verify the analytical results via simulations. 展开更多
关键词 Wireless powered communication networks cooperative communication RELAY hybrid optimization technique ant colony optimization particle swarm optimization
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HYBRID PERTURBATION-GALERKIN SOLUTION OF THE FLOW IN A CIRCULAR CROSS-SECTION TUBE WITH CONSTRICTION
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作者 沈新荣 高琪 +1 位作者 章本照 张金锁 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第2期219-227,共9页
Using hybrid perturbatin_Galerkin technique,a crcular cross_section tube model with sinusoidal wall is studied.This technique can remove the limitation of small parameters for perturbation and the difficulty of select... Using hybrid perturbatin_Galerkin technique,a crcular cross_section tube model with sinusoidal wall is studied.This technique can remove the limitation of small parameters for perturbation and the difficulty of selecting good coordinate functions about Galerkin technique.The effects caused by the boundary conditions and the Reynolds number on the flow were discussed.The position of the separate and reattachment points was obtained.The tendency of the variation about the shear stress on the wall and friction factor along the axis direction were also analyzed.The results at a small parameter have good agreements with the perturbation ones. 展开更多
关键词 hybrid perturbation-Galerkin technique circular cross-section tube with constriction blood flow
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In vitro Cyto and Blood Compatibility of Titanium Containing Diamond-Like Carbon Prepared by Hybrid Sputtering Method
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作者 Krishnasamy NAVANEETHA PANDIYARAJ Jan HEEG +5 位作者 Andreas LAMPKA Fabian JUNGE Torsten BARFELS Marion WIENECKE Young Ha RHEE Hyoung Woo KIM 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第9期829-836,共8页
In recent years, diamond-like carbon films (DLC) have been given more attention in research in the biomedical industry due to their potential application as surface coating on biomedical materials such as metals and... In recent years, diamond-like carbon films (DLC) have been given more attention in research in the biomedical industry due to their potential application as surface coating on biomedical materials such as metals and polymer substrates. There are many ways to prepare metal containing DLC films deposited on polymeric film substrates, such as coatings from car- bonaceous precursors and some means that incorporate other elements. In this study, we in- vestigated both the surface and biocompatible properties of titanium containing DLC (Ti-DLC) films. The Ti-DLC films were prepared on the surface of poly (ethylene terephthalate) (PET) film as a function of the deposition power level using reactive sputtering technique. The films' hydrophilicity was studied by contact angle and surface energy tests. Their surface morphology was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their elemental chemical composition was analyzed using energy dispersive X-spectra (EDX) and X-ray photoelectron spectroscopy (XPS). Their blood and cell compatibility was studied by in vitro tests, including tests on platelet adhesion, thrombus formation, whole blood clotting time and osteoblast cell compatibility. Significant changes in the morphological and chemical composition of the Ti-DLC films were observed and found to be a function of the deposition level. These morphological and chemical changes reduced the interfacial tension between Ti-DLC and blood proteins as well as resisted the adhesion and activation of platelets on the surface of the Ti-DLC films. The cell compatibility results exhibited significant growth of osteoblast cells on the surface of Ti incorporated DLC film compared with that of DLC film surface. 展开更多
关键词 Ti-DLC hybrid reactive sputtering technique surface analysis cyto and blood compatibility
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Medical Image Application by Hybrid Transform Coding Scheme
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作者 Hawar Hawar 《通讯和计算机(中英文版)》 2021年第2期26-30,共5页
Efficient compression of images using hybrid schemes has become the spotlight for developers in recent times.Hybrid compression techniques(DWT and DCT)are the basis of the proposed compression scheme presented in this... Efficient compression of images using hybrid schemes has become the spotlight for developers in recent times.Hybrid compression techniques(DWT and DCT)are the basis of the proposed compression scheme presented in this paper.The aim here is to achieve higher compression threshold while maintaining the quality of the reconstructed image,attempting to achieve this by using different compression levels on wavelet coefficients of the DWT(HH and LL)bands,in the time when(HL and LH)bands are undergoing DCT transform.According to the type of transformation,adaptive quantization of the retained coefficient is performed.Lastly the quantization indices are encoded using entropy coding(variable shift coding).Results of our trails indicate using hybrid DWT-DCT algorithm significantly improves coding performance. 展开更多
关键词 DWT DCT hybrid compression techniques
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Mode Ⅲ fracture analysis by Trefftz boundary element method
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作者 Yuhong Cui Juan Wang +1 位作者 Manicka Dhanasekar Qinghua Qin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第2期173-181,共9页
This paper presents a hybrid Trefftz (HT) boundary element method (BEM) by using two indirect techniques for mode III fracture problems. Two Trefftz complete functions of Laplace equation for normal elements and a... This paper presents a hybrid Trefftz (HT) boundary element method (BEM) by using two indirect techniques for mode III fracture problems. Two Trefftz complete functions of Laplace equation for normal elements and a special purpose Trefftz function for crack elements are proposed in deriving the Galerkin and the collocation techniques of HT BEM. Then two auxiliary functions are introduced to improve the accuracy of the displacement field near the crack tips, and stress intensity factor (SIF) is evaluated by local crack elements as well. Furthermore, numerical examples are given, including comparisons of the present results with the analytical solution and the other numerical methods, to demonstrate the efficiency for different boundary conditions and to illustrate the convergence influenced by several parameters. It shows that HT BEM by usingthe Galerkin and the collocation techniques is effective for mode III fracture problems. 展开更多
关键词 Hybrid Trefftz method. Galerkin technique .Point-collocation technique .Mode III fracture
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Enhanced heavy and extra heavy oil recovery:Current status and new trends
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作者 Sayed Gomaa Khalaf G.Salem A.N.El-hoshoudy 《Petroleum》 EI CSCD 2024年第3期399-410,共12页
Due to the increased demand for energy resources these days,especially due to the Russian-Ukrainian war,the focus of the major countries is turning strongly towards improving oil production,especially heavy and extra ... Due to the increased demand for energy resources these days,especially due to the Russian-Ukrainian war,the focus of the major countries is turning strongly towards improving oil production,especially heavy and extra heavy oil,which represents 40%of the world oil reserve.Steam-based and thermal(EOR)procedures are promising techniques for recovering heavy oil reservoirs,but they suffer from a sequence of problems and complications that arise after long-term application.These complications comprise steam breakthrough,steam overlap,and steam/rock interactions.This research presents the currently applied techniques to maximize the productivity of heavy oil,such as steam injection,cyclic steam stimulation,in-situ combustion,and steam-assisted gravity drainage.Thermal technologies face numerous obstacles,as they are energy and water-intensive processes that are not environmentally friendly.The research also presents future trends in energy-saving and environmentally friendly techniques that enhance heavy oil recovery through vapor extraction(VAPEX)steam-solvent hybrid techniques,electromagnetic energy,sonication,and nanotechnology.The findings of this review reported that all the presented techniques focus on how to reduce the oil viscosity and in-situ upgrade the crude oil properties.In turn,these enhance both the productivity rate and oil recovery and minimize the production cost.This article can be considered a comprehensive review of thermal recovery methods in heavy and extra-heavy oil,in addition to screening criteria used for each method. 展开更多
关键词 Enhanced oil recovery Heavy crude oil Steam flood Hybrid techniques NANOTECHNOLOGY
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A new hybrid control technique for operation of DC microgrid under islanded operating mode 被引量:5
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作者 Vahid Mortezapour Sajjad Golshannavaz +1 位作者 Edris Pouresmaeil Amin Yazdaninejadi 《Protection and Control of Modern Power Systems》 2022年第1期646-656,共11页
This study proposes a novel combined primary and secondary control approach for direct current microgrids,specifi-cally in islanded mode.In primary control,this approach establishes an appropriate load power sharing b... This study proposes a novel combined primary and secondary control approach for direct current microgrids,specifi-cally in islanded mode.In primary control,this approach establishes an appropriate load power sharing between the distributed energy resources based on their rated power.Simultaneously,it considers the load voltage deviation and provides satisfactory voltage regulation in the secondary control loop.The proposed primary control is based on an efficient droop mechanism that only deploys the local variable measurements,so as to overcome the side effects caused by communication delays.In the case of secondary control,two different methods are devised.In the first,low bandwidth communication links are used to establish the minimum required data transfer between the converters.The effect of communication delay is further explored.The second method excludes any communication link and only uses local variables.Accordingly,a self-sufficient control loop is devised without any communication require-ment.The proposed control notions are investigated in MATLAB/Simulink platform to highlight system performance.The results demonstrate that both proposed approaches can effectively compensate for the voltage deviation due to the primary control task.Detailed comparisons of the two methods are also provided. 展开更多
关键词 Hybrid control technique Modern power system DC microgrid Islanded operating mode
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Fabrication of 2×2 Thermo-Optic Switches with Organic-Inorganic Hybrid Materials Prepared by Sol-Gel Technique
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作者 Xianjiang Wang, Lei Xu, Dongxiao Li, Liying Liu, and Wencheng WangState Key Lab for Advanced Photonic Materials and Devices, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, P. R. China 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期265-266,共2页
2×2 Mach-Zehnder interferometric thermo-optic switch was fabricated with organic/inorganic hybrid materials by sol-gel technique and direct UV patterning. The switching time of device was measured to be 4.2 ms an... 2×2 Mach-Zehnder interferometric thermo-optic switch was fabricated with organic/inorganic hybrid materials by sol-gel technique and direct UV patterning. The switching time of device was measured to be 4.2 ms and switching power 9.3 mW. 展开更多
关键词 of on by with Thermo-Optic Switches with Organic-Inorganic Hybrid Materials Prepared by Sol-Gel technique Fabrication of 2
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