查看更多>>摘要：The rapid growth of passenger flow in urban rail transit has led to great service pressures for metro companies in organizing train services to provide higher transportation capacities in order to satisfy passengers'travel demand,especially on those metro lines with insufficient rolling stock.In order to cope with high passenger flow service pressure,a mixed integer nonlinear programming(MINLP)model is proposed to optimize the line plan,timetable and rolling stock circulation simultaneously,to reduce the number of rolling stocks and increase the number of full-length services.A two-step algorithm strategy is proposed.In the first stage,the train timetable is optimized under the assumption that all the train services are the full-length services.In the second stage,the rolling stock plan is optimized based on the timetable optimized in the first stage.To ensure a feasible rolling stock circulation,certain full-length services are shortened to the short-length services due to the limited number of rolling stocks.Numerical experiments are performed based on the real-life data of Shanghai Metro Line 8.Results show that the proposed method can efficiently optimize the timetable and rolling stock circulation of the whole operation day.The optimized results are beneficial for both the service and the operational costs.
查看更多>>摘要：Multi-point array flexible tooling based on multilateration is widely used in the processing and manufacturing of complex curved surface parts.However,during the positioning of workpieces,the force exerted on each flexible support point is not uniform,and there exists force coupling between the support units.In response to the force coupling problem in the multi-point array positioning support process,a coordinated control method for the support force of multi-point array positioning combining correlation coefficient and regression analysis was proposed in this paper.The Spearman correlation coefficient was adopted in this method to study the force coupling correlation between positioning points,and a mathematical model of force coupling was established between positioning units through regression analysis,which can quickly and accurately perform coordinated control of the multilateration support system,and effectively improve the force interference of the multi-point array positioning support scene.
查看更多>>摘要：In this work,an actuate membrane and an electrode membrane were prepared by a sol-gel method.And then,they were physically pressed to form a chitosan-based ion actuator(CSIA).Importantly,the effect of sodium chloride on CSIA was investigated.The mechanical properties of CSIA were tested by establishing an output force test platform and a displacement test platform while testing its porosity.And,the electrochemical performance was tested by electrochemical workstation.At the end,the surface morphology and functional groups were measured by scanning electron microscopy and infrared spectrogram,respectively.The results indicated that the molar concentration of the sodium chloride was the best at 0.06836 mol·L-1 for CSIA.Its mechanical properties could reach an output force of 2.939 mN and a deflection displacement of 4.025 mm,and the maximum porosity of 12.98％at the same time.The specific capacitance of the electrochemical performance was up to 0.07719 F·g-1,and the minimum resistance reached 13.48 Ω.From the surface morphology and functional groups,the appropriate doping ratio of NaCl into CSIA was helpful for increasing the transport space of internal ions.The effective internal ion concentration and significantly reduced internal stress provided excellent performances under the appropriate voltage conditions.The doping of inorganic ion sodium chloride improved the internal electron transport efficiency of chitosan ion actuator,and it advanced the mechanical properties of the actuator.Hence the enhancement of NaCl output force in CSIA had a good significance for the development of inorganic salt ion strengthened ion actuator.
查看更多>>摘要：In recent times,an abrupt upswing has emerged within the data mining domain,particularly within the sphere of sentiment analysis.Encompassing diverse dimensions such as sentiment extraction,subjectivity categorization,opinion summarization,and spam detection,sentiment analysis,also acknowledged as Opinton Mining(OM),undertakes a mathematical exploration into the perspectives,emotions,evaluations,and conduct of individuals toward entities,encompassing products,services,individuals,and events.The advent of web technology tools empowers users to liberally articulate their opinions across varied online platforms,culminating in the generation of a substantial corpus of invaluable yet unstructured data.This exposition scrutinizes the importance of harnessing this data,delving into the intricate process of refining and metamorphosing it for subsequent operations like classification and aspect-oriented sentiment analysis.The crux of the discourse centers on a thorough scrutiny of four data mining algorithms deployed for prognostication and categorization,providing insights into their efficacy within the domain of sentiment analysis.This investigation transcends into pragmatic applications,challenges encountered in the field,and potential trajectories ahead,culminating in a nuanced comprehension of the dynamic panorama of sentiment analysis and its ramifications.
查看更多>>摘要：Nonlinear behavior is important in the vibration test of engineering structures.In this study,a constant response vibration test is proposed for nonlinear element extraction.The method is based on the principle of Harmonic Balance Method(HBM).The stiffness or damping can be regarded as constant for particular steady displacement or velocity response.The displacement or velocity is controlled as a constant in the test.Then the measured Frequency Response Function(FRF)is obtained.The equivalent stiffness or damping is estimated using FRFs for a particular vibration response level.The displacement-dependent stiffness and velocity-dependent damping are fitted to describe the unknown non-linearity.The nonlinear spring and damping force can be obtained by combining the fitting results with HBM using first-order expansion.Constant response vibration test is illustrated through experimental setup to verify its effectiveness.Experimental results show that the procedure is capable of achieving an accurate parameter identification of nonlinear damping and stiffness,which is hopeful for industrial application.
查看更多>>摘要：One of the nontraditional manufacturing processes is the chemical machining that deals with the removal of material substances using acidic or alkaline chemical solutions.This study aimed to determine the maximum material removal rate(MRR),and minimum surface roughness(SRa)of Ti-5Al-2.5Sn alloy during chemical milling that is possible to achieve by varying the etching chemical milling parameters in terms of time,concentration of the chemical solution[hydrofluoric acid(HF)and nitric acid(HNO3)],and chemical milling temperature.The Taguchi method based on a statistical design of experiments(DOE)technique with an L16 orthogonal array is efficiently used to obtain the objective of this study and to detect optimal chemical milling parameters for the Ti-5Al-2.5Sn alloy.The experimental results were analyzed using ANOVA analysis to determine the importance of each system parameter on the response variables(MRR and SRa).The optimal process parameters were found to be at a chemical solution concentration of 22.5％HF and 17％HNO3,a temperature of 45 ℃,and a time of 60 min.These parameters resulted in a maximum MRR of 0.0842 mg/min and a minimum SRa of 0.30 pm.The ANOVA result signalized that the concentration of the etching acids has the most impact on both responses with contribution percentages of 81％and 67％respectively.This takes a look at the efficacy of the Taguchi technique in optimizing chemical milling procedures and offers precious insights for selecting process parameters to attain favored results.
查看更多>>摘要：This paper presents an approach to improve medical image retrieval,particularly for brain tumors,by addressing the gap between low-level visual and high-level perceived contents in MRI,X-ray,and CT scans.Traditional methods based on color,shape,or texture are less effective.The proposed solution uses machine learning to handle high-dimensional image features,reducing computational complexity and mitigating issues caused by artifacts or noise.It employs a genetic algorithm for feature reduction and a hybrid residual UNet(HResUNet)model for Region-of-Interest(ROI)segmentation and classification,with enhanced image preprocessing.The study examines various loss functions,finding that a hybrid loss function yields superior results,and the GA-HResUNet model outperforms the HResUNet.Comparative analysis with state-of-the-art models shows a 4％improvement in retrieval accuracy.
查看更多>>摘要：Diabetes is a significant issue in the medical field.The detection and identification of the human eye diseases caused by excessive blood sugar levels in diabetes mellitus are important.The main objective of this study is to propose a viable solution for diagnosis using fundus images.This study presents a stage by stage implementation methodology.The original fundus image is first preprocessed,then the blood vessels are segmented,and finally the features are extracted and classified.This work uses an effective way to introduce a meta-heuristic algorithm.Blood Vessel Segmentation(BVS)is vital in DR(Diabetic Retinopathy)detection;hence,this research proposes a Firefly-Optimized Frangi based Filter(FOFF).Categorizing the disease is the last procedure.The classifier K-Nearest Neighbour(KNN)has an accuracy of 91.62％,while the SVM does well with an accuracy score of 95.54％.
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