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Not in Control,but Liable?Attributing Human Responsibility for Fully Automated Vehicle Accidents
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作者 Siming Zhai Lin Wang Peng Liu 《Engineering》 SCIE EI CAS CSCD 2024年第2期121-132,共12页
Human agency has become increasingly limited in complex systems with increasingly automated decision-making capabilities.For instance,human occupants are passengers and do not have direct vehicle control in fully auto... Human agency has become increasingly limited in complex systems with increasingly automated decision-making capabilities.For instance,human occupants are passengers and do not have direct vehicle control in fully automated cars(i.e.,driverless cars).An interesting question is whether users are responsible for the accidents of these cars.Normative ethical and legal analyses frequently argue that individuals should not bear responsibility for harm beyond their control.Here,we consider human judgment of responsibility for accidents involving fully automated cars through three studies with seven experiments(N=2668).We compared the responsibility attributed to the occupants in three conditions:an owner in his private fully automated car,a passenger in a driverless robotaxi,and a passenger in a conventional taxi,where none of these three occupants have direct vehicle control over the involved vehicles that cause identical pedestrian injury.In contrast to normative analyses,we show that the occupants of driverless cars(private cars and robotaxis)are attributed more responsibility than conventional taxi passengers.This dilemma is robust across different contexts(e.g.,participants from China vs the Republic of Korea,participants with first-vs third-person perspectives,and occupant presence vs absence).Furthermore,we observe that this is not due to the perception that these occupants have greater control over driving but because they are more expected to foresee the potential consequences of using driverless cars.Our findings suggest that when driverless vehicles(private cars and taxis)cause harm,their users may face more social pressure,which public discourse and legal regulations should manage appropriately. 展开更多
关键词 fully automated vehicle accidents Responsibility attribution CONTROLLABILITY Foreseeability
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Enhancing efficiency and stability of organic solar cells through a simplified four-step synthesis of fully non-fused ring electron acceptor
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作者 Chenyang Han Huanhuan Gao +7 位作者 Yanna Sun Yuanyuan Kan Zhaozhao Bi Wei Ma Yani Zhang Juan Antonio Zapien Yingguo Yang Ke Gao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期601-608,I0015,共9页
Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be realized.Herein,two medium bandgap fu... Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be realized.Herein,two medium bandgap fully non-fused ring electron acceptors(NFREAs,medium bandgap,i,e.,1,3-1,8 eV),namely PTR-2Cl and PTR-4Cl are synthesized with only four steps by using intramolecular noncovalent interaction central core,structured alkyl side chain orientation linking units and flanking with different electron-withdrawing end group.Among them,PTR-4C1 exhibits increased average electrostatic potential(ESP)difference with polymer donor,enhanced crystallinity and compactπ-πstacking compared with the control molecule PTR-2CI.As a result,the PTR-4Cl-based OSC achieved an impressive power conversion efficiency(PCE)of 14.72%,with a much higher open-circuit voltage(V_(OC))of 0.953 V and significantly improved fill factor(FF)of 0.758,demonstrating one of the best acceptor material in the top-performing fully NFREA-based OSCs with both high PCE and V_(OC).Notably,PTR-4Cl-based cells maintain a good T_80lifetime of its initial PCE after over 936 h under a continuous thermal annealing treatment and over1300 h T_(80)lifetime without encapsulation.This work provides a cost-effective design strategy for NFREAs on obtaining high V_(OC),efficient exciton dissociation,and ordered molecular packing and thus high-efficiency and stable OSCs. 展开更多
关键词 Organic solar cells fully non-fused ring acceptors End group engineering Morphology regulation High efficiency
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Design of Fully Automatic Specification Selection System for Resistance Welding Equipment
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作者 Xiangkun Lu Zengtai Tian +1 位作者 Hao Xu Yue Guo 《Journal of Harbin Institute of Technology(New Series)》 CAS 2024年第1期64-68,共5页
A system for fully automatic selection of welding specifications in resistance welding equipment has been developed to address the problem of workers frequently choosing the wrong specifications during manual welding ... A system for fully automatic selection of welding specifications in resistance welding equipment has been developed to address the problem of workers frequently choosing the wrong specifications during manual welding of multiple parts on a single machine in automobile factories. The system incorporates an automatic recognition system for different workpiece materials using the added machine fixture,visual detection system for nuts and bolts,and secondary graphical confirmation to ensure the correctness of specification calling. This system achieves reliable,fully automatic selection of welding specifications in resistance welding equipment and has shown significant effects in improving welding quality for massproduced workpieces,while solving the problem of specification calling errors that can occur with traditional methods involving process charts and code adjustments. This system is particularly suitable for promoting applications in manual welding of multiple parts on a single machine in automobile factories,ensuring correct specification calling and welding quality. 展开更多
关键词 seat spot welding welding specifications fully automatic
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Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach
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作者 Yi Yu Guo-Ping Liu +1 位作者 Yi Huang Peng Shi 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第2期405-417,共13页
DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately por... DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method. 展开更多
关键词 DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control
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Observer-based robust high-order fully actuated attitude autopilot design for spinning glide-guided projectiles
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作者 Wei Wang Yuchen Wang +2 位作者 Shiwei Chen Yongcang Guo Zhongjiao Shi 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期282-294,共13页
This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theor... This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial conditions.By introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated systems.Subsequently,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired eigenstructure.Under the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov method.Validation of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations. 展开更多
关键词 Spinning glide-guided projectile Attitude control Sliding mode disturbance observer Fixed-time stable theory High-order fully actuated approach
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GRU-integrated constrained soft actor-critic learning enabled fully distributed scheduling strategy for residential virtual power plant
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作者 Xiaoyun Deng Yongdong Chen +2 位作者 Dongchuan Fan Youbo Liu Chao Ma 《Global Energy Interconnection》 EI CSCD 2024年第2期117-129,共13页
In this study,a novel residential virtual power plant(RVPP)scheduling method that leverages a gate recurrent unit(GRU)-integrated deep reinforcement learning(DRL)algorithm is proposed.In the proposed scheme,the GRU-in... In this study,a novel residential virtual power plant(RVPP)scheduling method that leverages a gate recurrent unit(GRU)-integrated deep reinforcement learning(DRL)algorithm is proposed.In the proposed scheme,the GRU-integrated DRL algorithm guides the RVPP to participate effectively in both the day-ahead and real-time markets,lowering the electricity purchase costs and consumption risks for end-users.The Lagrangian relaxation technique is introduced to transform the constrained Markov decision process(CMDP)into an unconstrained optimization problem,which guarantees that the constraints are strictly satisfied without determining the penalty coefficients.Furthermore,to enhance the scalability of the constrained soft actor-critic(CSAC)-based RVPP scheduling approach,a fully distributed scheduling architecture was designed to enable plug-and-play in the residential distributed energy resources(RDER).Case studies performed on the constructed RVPP scenario validated the performance of the proposed methodology in enhancing the responsiveness of the RDER to power tariffs,balancing the supply and demand of the power grid,and ensuring customer comfort. 展开更多
关键词 Residential virtual power plant Residential distributed energy resource Constrained soft actor-critic fully distributed scheduling strategy
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Fuzzy Inventory Model under Selling Price Dependent Demand and Variable Deterioration with Fully Backlogged Shortages
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作者 Tanzim S. Shaikh Santosh P. Gite 《American Journal of Operations Research》 2024年第2期87-103,共17页
The objective is to develop a model considering demand dependent on selling price and deterioration occurs after a certain period of time, which follows two-parameter Weibull distribution. Shortages are allowed and fu... The objective is to develop a model considering demand dependent on selling price and deterioration occurs after a certain period of time, which follows two-parameter Weibull distribution. Shortages are allowed and fully backlogged. Fuzzy optimal solution is obtained by considering hexagonal fuzzy numbers and for defuzzification Graded Mean Integration Representation Method. A numerical example is provided for the illustration of crisp and fuzzy, both models. To observe the effect of changes in parameters, sensitivity analysis is carried out. 展开更多
关键词 DETERIORATION Selling Price Dependent Demand fully Backlogged Hexagonal Fuzzy Numbers Graded Mean Integration Representation Method
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Review on the fully mulched ridge–furrow system for sustainable maize production on the semi-arid Loess Plateau 被引量:1
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作者 WANG Jin-bin XIE Jun-hong +1 位作者 LI Ling-ling ADINGO Samuel 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第5期1277-1290,共14页
The fully mulched ridge–furrow(FMRF) system has been widely used on the semi-arid Loess Plateau of China due to its high maize(Zea mays L.) productivity and rainfall use efficiency. However, high outputs under this s... The fully mulched ridge–furrow(FMRF) system has been widely used on the semi-arid Loess Plateau of China due to its high maize(Zea mays L.) productivity and rainfall use efficiency. However, high outputs under this system led to a depletion of soil moisture and soil nutrients, which reduces its sustainability in the long run. Therefore, it is necessary to optimize the system for the sustainable development of agriculture. The development, yield-increasing mechanisms,negative impacts, optimization, and their relations in the FMRF system are reviewed in this paper. We suggest using grain and forage maize varieties instead of regular maize;mulching plastic film in autumn or leaving the mulch after maize harvesting until the next spring, and then removing the old film and mulching new film;combining reduced/notillage with straw return;utilizing crop rotation or intercropping with winter canola(Brassica campestris L.), millet(Setaria italica), or oilseed flax(Linum usitatissimum L.);reducing nitrogen fertilizer and partially replacing chemical fertilizer with organic fertilizer;using biodegradable or weather-resistant film;and implementing mechanized production. These integrations help to establish an environmentally friendly, high quality, and sustainable agricultural system, promote highquality development of dryland farming, and create new opportunities for agricultural development in the semi-arid Loess Plateau. 展开更多
关键词 fully mulched ridge–furrow SYSTEM SEMI-ARID LOESS Plateau maize productivity farming SYSTEM sustainability
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Fully Bio-Based Composites of Poly(Lactic Acid)Reinforced with Cellulose-Graft-Poly-(ε-Caprolactone)Copolymers 被引量:1
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作者 Chengtao Gao Yang Wu Haibo Xie 《Journal of Renewable Materials》 SCIE EI 2023年第3期1137-1152,共16页
Due to the increasing demand for modified polylactide(PLA)meeting“double green”criteria,the research on sustainable plasticizers for PLA has attracted broad attentions.This study reported an open-ring polymerization... Due to the increasing demand for modified polylactide(PLA)meeting“double green”criteria,the research on sustainable plasticizers for PLA has attracted broad attentions.This study reported an open-ring polymerization method to fabricate cellulose(MCC)-g-PCL(poly(ε-caprolactone))copolymers with a fully sustainable and biodegradable component.MCC-g-PCL copolymers were synthesized,characterized,and used as green plasticizers for the PLA toughening.The results indicated that the MCC-g-PCL derivatives play an important role in the compatibility,crystallization,and toughening of the PLA/MCC-g-PCL composites.The mechanical properties of the fully bio-based PLA/MCC-g-PCL composites were optimized by adding 15 wt%MCC-g-PCL,that is,the elongation at break was 22.6%(~376%higher than that of neat PLA),the tensile strength was 47.3 MPa(comparable to that of neat PLA),and the impact strength was 26 J/m(~130%higher than that of neat PLA).DSC results indicated that MCC-g-PCL reduced the Tg of the PLA blend.When the addition amount was 15 wt%,the Tg of the blend was 58.4°C.Compared with MCC,MCC-g-PCL polyester plasticizer has better thermal stability,T5%(°C)can still be maintained above 300°C.The rheological results showed that MCC-g-PCL acted as a plasticizer,the introduction of PCL flexible chain increased the mobility of PLA molecular chain,and decreased the complex viscosity,storage modulus and loss modulus of PLA blends.The MCC-g-PCL derivatives,as a new green plastic additive,have shown an interesting prospect to prepare fully bio-based composites. 展开更多
关键词 Green plasticizers PLA cellulose(MCC)-g-PCL fully bio-based composites
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Fully asynchronous distributed optimization with linear convergence over directed networks
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作者 SHA Xingyu ZHANG Jiaqi YOU Keyou 《中山大学学报(自然科学版)(中英文)》 CAS CSCD 北大核心 2023年第5期1-23,共23页
We study distributed optimization problems over a directed network,where nodes aim to minimize the sum of local objective functions via directed communications with neighbors.Many algorithms are designed to solve it f... We study distributed optimization problems over a directed network,where nodes aim to minimize the sum of local objective functions via directed communications with neighbors.Many algorithms are designed to solve it for synchronized or randomly activated implementation,which may create deadlocks in practice.In sharp contrast,we propose a fully asynchronous push-pull gradient(APPG) algorithm,where each node updates without waiting for any other node by using possibly delayed information from neighbors.Then,we construct two novel augmented networks to analyze asynchrony and delays,and quantify its convergence rate from the worst-case point of view.Particularly,all nodes of APPG converge to the same optimal solution at a linear rate of O(λ^(k)) if local functions have Lipschitz-continuous gradients and their sum satisfies the Polyak-?ojasiewicz condition(convexity is not required),where λ ∈(0,1) is explicitly given and the virtual counter k increases by one when any node updates.Finally,the advantage of APPG over the synchronous counterpart and its linear speedup efficiency are numerically validated via a logistic regression problem. 展开更多
关键词 fully asynchronous distributed optimization linear convergence Polyak-Łojasiewicz condition
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Shallow sea topography detection using fully Polarimetric Gaofen-3 SAR data based on swell patterns
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作者 Longyu Huang Chenqing Fan +2 位作者 Junmin Meng Jungang Yang Jie Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第2期150-162,共13页
Compared to single-polarization synthetic aperture radar(SAR)data,fully polarimetric SAR data can provide more detailed information of the sea surface,which is important for applications such as shallow sea topography... Compared to single-polarization synthetic aperture radar(SAR)data,fully polarimetric SAR data can provide more detailed information of the sea surface,which is important for applications such as shallow sea topography detection.The Gaofen-3 satellite provides abundant polarimetric SAR data for ocean research.In this paper,a shallow sea topography detection method was proposed based on fully polarimetric Gaofen-3 SAR data.This method considers swell patterns and only requires SAR data and little prior knowledge of the water depth to detect shallow sea topography.Wave tracking was performed based on preprocessed fully polarimetric SAR data,and the water depth was then calculated considering the wave parameters and the linear dispersion relationships.In this paper,four study areas were selected for experiments,and the experimental results indicated that the polarimetric scattering parameterαhad higher detection accuracy than quad-polarization images.The mean relative errors were 14.52%,10.30%,12.56%,and 12.90%,respectively,in the four study areas.In addition,this paper also analyzed the detection ability of this model for different topographies,and the experiments revealed that the topography could be well recognized when the topography gradient is small,the topography gradient direction is close to the wave propagation direction,and the isobath line is regular. 展开更多
关键词 fully polarimetric SAR shallow sea topography Gaofen-3 swell patterns
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CNTFET Based Fully Differential First Order All Pass Filter
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作者 Muhammad I.Masud Iqbal A.Khan 《Computer Systems Science & Engineering》 SCIE EI 2023年第3期2425-2438,共14页
A novel,carbon nanotubefield effect transistor(CNTFET)based fully differentialfirst order all passfilter(FDFAPF)circuit configuration is presented.The FDFAPF uses CNTFET based negative transconductors(NTs)and positive... A novel,carbon nanotubefield effect transistor(CNTFET)based fully differentialfirst order all passfilter(FDFAPF)circuit configuration is presented.The FDFAPF uses CNTFET based negative transconductors(NTs)and positive transconductors(PTs)in its realization.The proposed circuit topology employs two PTs,two NTs,two resistors and one capacitor.All the passive components of the realized topology are grounded.Active only fully differentialfirst order all passfilter(AO-FDFAPF)topology is also derived from the proposed FDFAPF.The electronic tunability of the AO-FDFAPF is obtained by controlling the employed CNTFET based varactor.A tunabilty of pole frequency in the range of 10.5 to 26 GHz is obtained.Both the circuits are potential candidates for high frequency fully differential analog signal processing applications.As compared to prior state-of-the-art works,both the realized topologies have achieved highest pole frequency and lowest power dissipation.Moreover,they utilize compact circuit structures and suitable for low voltage applications.Moreover,both topologies work equally well in the deep submicron.The proposedfilters are analyzed and verified through HPSPICE simulations by utilizing Stanford CNTFET model at 16 nm technology node.It is observed that the proposed circuit simulation outcomes verify the theory. 展开更多
关键词 fully differential CNTFET all passfilters pole frequency TUNABILITY
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Effect of periodic heat transfer on the transient thermal behavior of a convective-radiative fully wet porous moving trapezoidal fin
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作者 B.J.GIREESHA M.L.KEERTHI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第4期653-668,共16页
A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account a... A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account along with the temperature sensitive thermal conductivity and convective heat transfer coefficients.The modeled problem,which is resolved into a non-linear partial differential equation(PDE),is made dimensionless and solved by employing the finite difference method(FDM).The results are displayed through graphs and discussed.The effects of amplitude,frequency of oscillation,wet nature,Peclet number,and other relevant quantities on the distribution of temperature through the fin length and with the dimensionless time are investigated.It is deciphered that the periodic heat transfer gives rise to the wavy nature of the fin thermal profile against time.The analysis is beneficial in the design of fin structures for applications like solar collectors,space/airborne applications,and refrigeration industries. 展开更多
关键词 convection fully wet porous fin trapezoidal profile moving fin unsteady periodic thermal condition
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Prediction of Uncertainty Estimation and Confidence Calibration Using Fully Convolutional Neural Network
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作者 Karim Gasmi Lassaad Ben Ammar +1 位作者 Hmoud Elshammari Fadwa Yahya 《Computers, Materials & Continua》 SCIE EI 2023年第5期2557-2573,共17页
Convolution neural networks(CNNs)have proven to be effective clinical imagingmethods.This study highlighted some of the key issues within these systems.It is difficult to train these systems in a limited clinical imag... Convolution neural networks(CNNs)have proven to be effective clinical imagingmethods.This study highlighted some of the key issues within these systems.It is difficult to train these systems in a limited clinical image databases,and many publications present strategies including such learning algorithm.Furthermore,these patterns are known formaking a highly reliable prognosis.In addition,normalization of volume and losses of dice have been used effectively to accelerate and stabilize the training.Furthermore,these systems are improperly regulated,resulting in more confident ratings for correct and incorrect classification,which are inaccurate and difficult to understand.This study examines the risk assessment of Fully Convolutional Neural Networks(FCNNs)for clinical image segmentation.Essential contributions have been made to this planned work:1)dice loss and cross-entropy loss are compared on the basis of segment quality and uncertain assessment of FCNNs;2)proposal for a group model for assurance measurement of full convolutional neural networks trained with dice loss and group normalization;And 3)the ability of the measured FCNs to evaluate the segment quality of the structures and to identify test examples outside the distribution.To evaluate the study’s contributions,it conducted a series of tests in three clinical image division applications such as heart,brain and prostate.The findings of the study provide significant insights into the predictive ambiguity assessment and a practical strategies for outside-distribution identification and reliable measurement in the clinical image segmentation.The approaches presented in this research significantly enhance the reliability and accuracy rating of CNNbased clinical imaging methods. 展开更多
关键词 Medical image SEGMENTATION confidence calibration uncertainty estimation fully convolutional neural network
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Existence and Uniqueness Results for a Fully Third-Order Boundary Value Problem
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作者 Xiaoming Liu Yongxiang Li 《Advances in Pure Mathematics》 2023年第8期495-503,共14页
The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have stud... The boundary value problems of the third-order ordinary differential equation have many practical application backgrounds and their some special cases have been studied by many authors. However, few scholars have studied the boundary value problems of the complete third-order differential equations u′′′(t) = f (t,u(t),u′(t),u′′(t)). In this paper, we discuss the existence and uniqueness of solutions and positive solutions of the fully third-order ordinary differential equation on [0,1] with the boundary condition u(0) = u′(1) = u′′(1) = 0. Under some inequality conditions on nonlinearity f some new existence and uniqueness results of solutions and positive solutions are obtained. 展开更多
关键词 fully Third-Order BVP SOLUTION Positive Solution Existence and Uniqueness Inequality Conditions
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Freeze-thaw Damage Laws and Model of Hydraulic Fully Graded Concrete
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作者 Jing XU Yanfu QIN 《Meteorological and Environmental Research》 CAS 2023年第2期8-14,共7页
On the basis of previous research results, the frost resistance of fully graded concrete and small wet sieving concrete specimens was compared and analyzed, and the characteristics and rules of freeze-thaw damage of h... On the basis of previous research results, the frost resistance of fully graded concrete and small wet sieving concrete specimens was compared and analyzed, and the characteristics and rules of freeze-thaw damage of hydraulic fully graded concrete after freeze-thaw cycles were analyzed through freeze-thaw test, impact-echo test, mechanical test and so on. Meanwhile, the damage characteristics of concrete in the salt and water freezing environment were compared. Through the mechanical test, it is found that the mechanical properties of both fully graded concrete and wet sieving concrete decreased to varying degrees after freeze-thaw cycles. The laws of uniaxial compression and tensile strength of concrete varying with the number of freeze-thaw cycles were obtained. The life of concrete after freeze-thaw cycles was predicted, and it is concluded that the life of concrete in the salt freezing environment was only 0.8 times that in the water freezing environment, proving once again that the damage of concrete in the salt freezing environment was more serious than that in the water freezing environment. Therefore, the grade of frost resistance should be improved appropriately for concrete engineering with salt solution. Finally, based on the damage theory and Lemaitre strain equivalence principle, the freeze-thaw damage evolution equation suitable for fully graded concrete was obtained. 展开更多
关键词 fully graded concrete Wet sieving concrete Salt freezing Temperature Durability Mechanical property
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Experimental Study on the Degradation of Hydraulic Fully Graded Concrete under Freeze-thaw Cycles
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作者 Jing XU 《Meteorological and Environmental Research》 CAS 2023年第1期41-47,共7页
In recent years,the winter temperature in southern China decreases year by year,and the phenomenon of freeze-thaw damage is also wide-spread in hydraulic buildings.In this paper,the freezing-thawing cycle tests of ful... In recent years,the winter temperature in southern China decreases year by year,and the phenomenon of freeze-thaw damage is also wide-spread in hydraulic buildings.In this paper,the freezing-thawing cycle tests of fully graded concrete specimens and corresponding wet sieving suitable for climate conditions in southern China were carried out,and the effects of freezing-thaw cycles on the appearance,mass loss,relative dynamic elastic modulus,internal temperature and strain of fully graded concrete and wet sieving concrete were studied.The splitting tensile strength test of concrete specimens with specified salt freezing cycles was carried out,and the relationship between the strength reduction of fully graded concrete and wet sieving concrete specimens and the number of freeze-thaw cycles was analyzed.The results show that with the increase of freeze-thaw cycles,the properties of fully graded concrete and wet sieving concrete degraded,and the degradation of compressive strength was the most significant,followed by the splitting tensile strength.In the initial stage of the freeze-thaw cycles,the degradation of each property was not obvious,and the deterioration rate of each property increased significantly after 100 freeze-thaw cycles.Besides,the relationship between the splitting tensile strength of fully graded concrete and wet sieving concrete and the internal wave velocity after freeze-thaw cycles was established.The test results can provide theoretical basis for the design,repair,maintenance and life prediction of dams and offshore platforms in southern China. 展开更多
关键词 fully graded concrete Wet sieving concrete Salt freezing Temperature Durability Mechanical properties
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An Unbounded Fully Homomorphic Encryption Scheme Based on Ideal Lattices and Chinese Remainder Theorem
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作者 Zhiyong Zheng Fengxia Liu Kun Tian 《Journal of Information Security》 2023年第4期366-395,共30页
We propose an unbounded fully homomorphic encryption scheme, i.e. a scheme that allows one to compute on encrypted data for any desired functions without needing to decrypt the data or knowing the decryption keys. Thi... We propose an unbounded fully homomorphic encryption scheme, i.e. a scheme that allows one to compute on encrypted data for any desired functions without needing to decrypt the data or knowing the decryption keys. This is a rational solution to an old problem proposed by Rivest, Adleman, and Dertouzos [1] in 1978, and to some new problems that appeared in Peikert [2] as open questions 10 and open questions 11 a few years ago. Our scheme is completely different from the breakthrough work [3] of Gentry in 2009. Gentry’s bootstrapping technique constructs a fully homomorphic encryption (FHE) scheme from a somewhat homomorphic one that is powerful enough to evaluate its own decryption function. To date, it remains the only known way of obtaining unbounded FHE. Our construction of an unbounded FHE scheme is straightforward and can handle unbounded homomorphic computation on any refreshed ciphertexts without bootstrapping transformation technique. 展开更多
关键词 fully Homomorphic Encryption Ideal Lattices Chinese Remainder Theorem General Compact Knapsacks Problem
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丘陵山地果园全液压遥控式履带动力底盘设计与试验 被引量:2
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作者 李善军 陈辉龙 +3 位作者 彭际博 孟亮 张鑫 李明震 《农业机械学报》 EI CAS CSCD 北大核心 2024年第2期119-127,201,共10页
针对目前丘陵山地果园作业农用底盘整机体积大、行驶作业操作繁琐和通过性差等问题,结合丘陵山地果园开沟、除草和修剪等农艺管理环节的实际需求,设计了一款全液压遥控式履带动力底盘。首先,对动力底盘的整机结构和工作原理进行了阐述;... 针对目前丘陵山地果园作业农用底盘整机体积大、行驶作业操作繁琐和通过性差等问题,结合丘陵山地果园开沟、除草和修剪等农艺管理环节的实际需求,设计了一款全液压遥控式履带动力底盘。首先,对动力底盘的整机结构和工作原理进行了阐述;其次,对前置挂载机构、行走系、变幅宽底盘、液压系统、遥控系统等关键部件进行设计和相应的匹配选型;最后,对整机进行了性能试验。试验结果表明:动力底盘在最小幅宽(1220 mm)和最大幅宽(1620 mm)的直线行驶偏移率分别为2.24%和2.2%,均满足相应国家标准(≤6%)要求。底盘的转向机动性能良好,最小幅宽原地转弯半径为905 mm,可适应丘陵山地果园相对狭窄的坡地作业环境。遥控操作上下斜坡、翻越田埂、跨越畦沟等过程平稳,满足丘陵山地果园非结构化地形行走要求。挂载链式开沟器进行开沟作业时,沟深稳定系数为88.5%,沟宽稳定系数为92.5%,满足国家标准(≥85%)要求。整机工作性能满足丘陵果园复杂坡度地形管理作业要求,可为丘陵山地果园田间管理作业的有效实施提供综合应用平台和技术支撑。 展开更多
关键词 丘陵山地果园 全液压驱动 变幅宽履带动力底盘
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我国大倾角煤层开采技术变革与展望 被引量:1
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作者 伍永平 郎丁 +14 位作者 贠东风 解盘石 王红伟 高喜才 罗生虎 曾佑富 吕文玉 张艳丽 胡博胜 皇甫靖宇 周邦远 黄国春 王丽 李俊明 刘斌 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第1期25-51,共27页
大倾角煤层是我国煤炭资源的主要赋存样式之一。在地域分布上呈现出广泛性与区域性,据不完全统计,全国25个省、自治区、直辖市均涉及该类煤层开采,在中西部地区储量丰富、产量大、生产集中程度高。在赋存条件上呈现出多样性与复杂性,不... 大倾角煤层是我国煤炭资源的主要赋存样式之一。在地域分布上呈现出广泛性与区域性,据不完全统计,全国25个省、自治区、直辖市均涉及该类煤层开采,在中西部地区储量丰富、产量大、生产集中程度高。在赋存条件上呈现出多样性与复杂性,不同区域成煤时期不一,构造控煤过程迥异,形成了多样且复杂的开采条件,催生了不同的开采技术要求。大倾角煤层开采的技术难度大。煤层倾角导致采场围岩运动破坏呈现非对称性显现特征,支护系统稳定性控制与“三机”配套与协同、采准巷道布置与支护、工作面“人-机”环境安全保障等工作的难度显著加剧,严重制约了矿井安全高效开采。大倾角煤层开采的区域经济需求强,该类煤层赋存与生产较集中的区域多见以煤炭工业为主的资源型城市,经济结构相对单一,煤炭资源安全高效开发利用对区域能源保供、民生保障、经济保稳具有兜底作用。长期以来,大倾角煤层开采技术变革聚焦于解决“难”与“需”的矛盾,在采煤方法与工艺、岩层控制理论与技术、成套装备研制与应用3个方面不断完善、创新、发展,实现了由非机械化向机械化开采的转变,安全产效水平大幅提升,人员劳动强度大幅下降,作业环境显著改善。20世纪90年代中期,川煤集团绿水洞煤矿首次成功实现了大倾角中厚煤层长壁综采,冲破了大倾角煤层机械化开采技术“禁区”。在此示范作用下,大倾角厚煤层长壁综放开采、大采高综采、薄煤层伪俯斜长壁综采三项首创性工程实践先后取得成功。这一过程中创新了工作面非线性限位布置与调斜方式,确立了“支架-围岩”系统稳定性多维交互控制模式,研发了工作面成套装备,取得良好收效,综合机械化开采技术适用范围进一步拓宽。与此同时,大倾角煤层开采仍存在许多亟待突破的关键科学问题与技术瓶颈,导致自动化、智能化水平提升与近水平/缓倾斜煤层相较仍存在较大差距。需进一步强化倾斜层状煤系地层煤岩体采动力学行为研究,揭示其对采场围岩灾变的控制机制,并实现量化表征;需进一步阐明岩体承载结构-采场装备群组系统间的多维动态作用过程与规律,完善装备与围岩多维动态多目标协同控制理论与技术基础,实现技术转化应用。在科学问题取得突破的基础上进行采煤方法、回采工艺、岩层控制、成套装备的系统性技术创新与研发,破解大倾角煤层开采安全-产效双提升的制约技术瓶颈,使大倾角煤层综合机械化开采倾角上限在有可靠技术保障的前提下向上延伸(扩展),为实现自动化、智能化开采奠定基础。 展开更多
关键词 大倾角煤层 机械化开采 岩层控制 技术变革
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