Online programming platforms are popular in programming education.However,there has been no research investigating students’real opinions and expectations of the error feedback mechanisms,leaving educators without a ...Online programming platforms are popular in programming education.However,there has been no research investigating students’real opinions and expectations of the error feedback mechanisms,leaving educators without a solid data foundation when attempting to improve the error feedback mechanisms.This paper makes a survey of 834 students across various programming courses and investigates student perceptions of error feedback mechanisms on online programming platforms.It explores the effectiveness of existing feedback,student satisfaction,and preferences for potential improvements,focusing on automatic error localization and program repair mechanisms.Results reveal a significant portion of students are dissatisfied with current feedback due to its limited informativeness.Students also express a clear demand for stronger feedback mechanisms,such as error localization and repair hints.Nevertheless,they prefer feedback that subtly guides them toward solutions,rather than providing direct and explicit answers,valuing the opportunity to enhance their debugging skills.The findings suggest a need for balanced,educational-focused feedback mechanisms that aid learning while promoting independent problem-solving.展开更多
Every year, around the world, between 250,000 and 500,000 people suffer a spinal cord injury(SCI). SCI is a devastating medical condition that arises from trauma or disease-induced damage to the spinal cord, disruptin...Every year, around the world, between 250,000 and 500,000 people suffer a spinal cord injury(SCI). SCI is a devastating medical condition that arises from trauma or disease-induced damage to the spinal cord, disrupting the neural connections that allow communication between the brain and the rest of the body, which results in varying degrees of motor and sensory impairment. Disconnection in the spinal tracts is an irreversible condition owing to the poor capacity for spontaneous axonal regeneration in the affected neurons.展开更多
Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 str...Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 stroke survivors from two neurology wards into an intervention group(n=55)who received the stepped self-care program and a control group(n=55)who received usual care from June to December 2023.The Self-Care of Stroke Inventory,Stroke Self-Efficacy Questionnaire,and the short version of the Stroke Specific Quality of Life Scale were administered at baseline(T0),immediately post-intervention(T_(1)),and at 1-month(T_(2))and 3-month(T_(3))follow-ups.Data were analyzed using repeated measures analyses of variance,and generalized estimating equations.Results A total of 48 participants in the intervention group and 50 participants in the control group completed the study.No statistically significant differences were observed at T0 in any of the measured indicators(all P>0.05).The study showed significant group,time,and group×time interaction effects across the assessed outcomes(all P<0.05).Follow-up between-group comparisons at T_(1),T_(2),and T_(3) indicated that the intervention group had significantly higher scores in self-care maintenance,self-care monitoring,self-care management,self-efficacy,and quality of life than the control group(all P<0.001).Conclusions The stepped self-care program significantly improved self-care behaviors,self-efficacy,and quality of life among stroke survivors.These findings support the broader implementation of this approach in post-discharge home self-care.展开更多
To systematically elucidate the central role of the cardiac autonomic nervous system(ANS)in maintaining cardiovascular homeostasis,analyze the pathological mechanisms underlying its dysregulation,integrate multidiscip...To systematically elucidate the central role of the cardiac autonomic nervous system(ANS)in maintaining cardiovascular homeostasis,analyze the pathological mechanisms underlying its dysregulation,integrate multidisciplinary research findings from the U.S.stimulating peripheral nerves to alleviate disease symptoms(SPARC)program,and evaluate the unique advantages and current limitations of acupuncture in modulating cardiac ANS function,ultimately proposing novel strategies for the prevention and treatment of cardiovascular diseases.A systematic literature review was conducted to synthesize current knowledge on the fundamental regulatory mechanisms of the cardiac ANS,the SPARC program's innovative contributions to neuroanatomy and neural pathway mapping,as well as clinical and experimental evidence supporting acupuncture's modulation of the ANS.The SPARC program has made significant progress in elucidating the anatomical organization and neural circuitry of the cardiac ANS through interdisciplinary collaboration,offering novel insights and methodological frameworks for studying cardiac autonomic regulation.Acupuncture,as a cornerstone of traditional medicine,has demonstrated both specificity and multi-target regulatory effects on the cardiac ANS through clinical and experimental studies.However,challenges remain,including an incomplete mechanistic understanding,technical limitations in research methodologies,and difficulties in translating findings into clinical practice.Future research on acupuncture should build upon its inherent strengths while advancing its integration with modern scientific and technological approaches.Strengthening interdisciplinary collaboration and leveraging artificial intelligence can open new frontiers in mechanistic exploration and technological innovation.These efforts will facilitate the internationalization of acupuncture research and contribute innovative perspectives and therapeutic strategies for cardiovascular disease prevention and treatment.展开更多
In this paper,we study a class of Linear Fractional Programming on a nonempty bounded set,called the Problem(LFP),and design a branch and bound algorithm to find the global optimal solution of the problem(LFP).First,w...In this paper,we study a class of Linear Fractional Programming on a nonempty bounded set,called the Problem(LFP),and design a branch and bound algorithm to find the global optimal solution of the problem(LFP).First,we convert the problem(LFP)to the equivalent problem(EP2).Secondly,by applying the linear relaxation technique to the problem(EP2),the linear relaxation programming problem(LRP2Y)was obtained.Then,the overall framework of the algorithm is given,and the convergence and complexity of the algorithm are analyzed.Finally,experimental results are listed to illustrate the effectiveness of the algorithm.展开更多
The operational demands of a wide range significantly exacerbate combustion instability issues within ramjet combustor.To suppress combustion oscillations,an open-loop control system utilizing Linear Genetic Programmi...The operational demands of a wide range significantly exacerbate combustion instability issues within ramjet combustor.To suppress combustion oscillations,an open-loop control system utilizing Linear Genetic Programming(LGP)has been developed for a full-scale annular ramjet combustor.The LGP is used to generate control laws that include multi-frequency forcing.These laws are then transformed into square waves to actuate the solenoid valve,which modulates the kerosene supply for open-loop control.The results show that the duty cycle has little effect on instability amplitude,whereas an increase in frequency leads to a remarked reduction in combustion amplitude.After five generations evolvements,the pressure amplitude is reduced by 40.6% under the optimal control law generated by LGP.Furthermore,the machine learning process is depicted using a proximity map of control law similarity,with the search pathway visualized by the steepest descent.All individuals go forward to the upper left corner of the map with the evolution process,terminating at the optimal individual of the fifth generation.展开更多
Instrumental and expert assessments were used to assess the effect of massage on facial skin blood perfusion,as well as the effects of the long-term use of the two skin health programs on the water content of the stra...Instrumental and expert assessments were used to assess the effect of massage on facial skin blood perfusion,as well as the effects of the long-term use of the two skin health programs on the water content of the stratum corneum,F4,L^(*),dermal and epidermal thickness and density,facial wrinkles,and so on.Sixty healthy Chinese women were selected as the study subjects,which were subsequently divided into G1 non-massage group and G2 massage group.The results show that massage can increase the blood perfusion of facial skin.Group G2 solution is found to be more effective in improving the skin structural barrier(epidermal density),skin elasticity,firmness(dermal thickness)and forehead wrinkles.展开更多
Aiming at the problem of innovative talent training in the industry field in characteristic software colleges,combined with the actual situation of Software College of Northeastern University,this paper analyzes the c...Aiming at the problem of innovative talent training in the industry field in characteristic software colleges,combined with the actual situation of Software College of Northeastern University,this paper analyzes the construction requirements of characteristic talent training mode and training scheme,puts forward the reform of characteristic software innovative talent training scheme integrating production and education,and takes the characteristic direction of financial technology as an example to introduce the curriculum construction based on industry-education integration and school-enterprise cooperation.展开更多
The field of nanomedicine has been revolutionized by the concept of immunogenic cell death(ICD)-enhanced cancer therapy,which holds immense promise for the efficient treatment of cancer.However,precise delivery of ICD...The field of nanomedicine has been revolutionized by the concept of immunogenic cell death(ICD)-enhanced cancer therapy,which holds immense promise for the efficient treatment of cancer.However,precise delivery of ICD inducer is severely hindered by complex biological barriers.How to design and build intelligent nanoplatform for adaptive and dynamic cancer therapy remains a big challenge.Herein,this article presents the design and preparation of CD44-targeting and ZIF-8 gated gold nanocage(Au@ZH) for programmed delivery of the 1,2-diaminocyclohexane-Pt(Ⅱ)(DACHPt) as ICD inducer.After actively targeting the CD44 on the surface of 4T1 tumor cell,this Pt-Au@ZH can be effectively endocytosed by the 4T1 cell and release the DACHPt in tumor acidic environment,resulting in ICD effect and superior antitumor efficacy both in vitro and in vivo in the presence of mild 808 nm laser irradiation.By integration of internal and external stimuli intelligently,this programmed nanoplatform is poised to become a cornerstone in the pursuit of effective and targeted cancer therapy in the foreseeable future.展开更多
During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive...During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive distance)to a moving target as quickly as possible,resulting in the extended minimum-time intercept problem(EMTIP).Existing research has primarily focused on the zero-distance intercept problem,MTIP,establishing the necessary or sufficient conditions for MTIP optimality,and utilizing analytic algorithms,such as root-finding algorithms,to calculate the optimal solutions.However,these approaches depend heavily on the properties of the analytic algorithm,making them inapplicable when problem settings change,such as in the case of a positive effective range or complicated target motions outside uniform rectilinear motion.In this study,an approach employing a high-accuracy and quality-guaranteed mixed-integer piecewise-linear program(QG-PWL)is proposed for the EMTIP.This program can accommodate different effective interception ranges and complicated target motions(variable velocity or complicated trajectories).The high accuracy and quality guarantees of QG-PWL originate from elegant strategies such as piecewise linearization and other developed operation strategies.The approximate error in the intercept path length is proved to be bounded to h^(2)/(4√2),where h is the piecewise length.展开更多
Programmable/reprogrammable magneto-responsive composites(MRCs)are highly desirable for applications in soft robotics,morphable actuators,and biomedical devices due to their capabilities of undergoing reversible,compl...Programmable/reprogrammable magneto-responsive composites(MRCs)are highly desirable for applications in soft robotics,morphable actuators,and biomedical devices due to their capabilities of undergoing reversible,complex,untethered,and rapid deformations.However,current MRC-based devices primarily rely on soft matrices,which revert to their original shapes and cease functioning when external magnetic fields are removed.Moreover,their magnetization programming,deformations,and functioning need to alternate between encoding and actuation platforms,limiting the adaptability and efficiency.Here,we present a reprogrammable magnetic shape-memory composite(RM-SMC)integrating a shape-memory polymer(SMP)skeleton with phase-transition magnetic microcapsules.High-intensity laser melts microcapsules for magnetic realignment under programmed fields,while low-intensity laser softens SMP for structural reconfiguration without compromising integrity.This dual-laser strategy facilitates in situ magnetization programming,shape morphing,and function execution within a single material system.Our innovative approach enables unique applications,including omnidirectional multi-degree-of-freedom actuators that can activate light switches,solar trackers that optimize energy capture,and adaptive impellers that modulate fluid pumping.By eliminating platform alternation and enabling shape/function retention post-actuation,the RM-SMC platform overcomes critical limitations in conventional MRCs,establishing a paradigm for multifunctional devices requiring persistent configuration control and field-independent operation.展开更多
In this paper,a security defense issue is investigated for networked control systems susceptible to stochastic denial of service(DoS) attacks by using the sliding mode control method.To utilize network communication r...In this paper,a security defense issue is investigated for networked control systems susceptible to stochastic denial of service(DoS) attacks by using the sliding mode control method.To utilize network communication resources more effectively,a novel adaptive event-triggered(AET) mechanism is introduced,whose triggering coefficient can be adaptively adjusted according to the evolution trend of system states.Differing from existing event-triggered(ET) mechanisms,the proposed one demonstrates exceptional relevance and flexibility.It is closely related to attack probability,and its triggering coefficient dynamically adjusts depending on the presence or absence of an attack.To leverage attacker information more effectively,a switching-like sliding mode security controller is designed,which can autonomously select different controller gains based on the sliding function representing the attack situation.Sufficient conditions for the existence of the switching-like sliding mode secure controller are presented to ensure the stochastic stability of the system and the reachability of the sliding surface.Compared with existing time-invariant control strategies within the triggered interval,more resilient defense performance can be expected since the correlation with attack information is established in both the proposed AET scheme and the control strategy.Finally,a simulation example is conducted to verify the effectiveness and feasibility of the proposed security control method.展开更多
Ultrastructural features of nucleus degradation during programmed cell death (PCD) of starchy endosperm cells in rice ( Oryza sativa L.) were observed using transmission electron microscopy. Several distinct morpho...Ultrastructural features of nucleus degradation during programmed cell death (PCD) of starchy endosperm cells in rice ( Oryza sativa L.) were observed using transmission electron microscopy. Several distinct morphological features of PCD have been found in the developing starchy endosperm cells, e.g. nucleus deformation, chromatin condensation, nuclear envelope disruption, and nuclear matrix leakage. DNA ladder displayed a smear of large DNA fragments from nucleus and evident bands of small DNA fragments (140-180 bp) from both nucleus and cytoplasm. In contrast with the rapid nucleus degradation, cell organelles in cytoplasm, such as rough endoplasmic reticulum, amyloplast, and mitochondrion, maintained their metabolic functions for a longer time. Seed reserves were continually synthesized and accumulated in the starchy endosperm cells despite the nucleus degradation during the PCD process. These results suggest that starchy endosperm cells remain active during reserve material synthesis and accumulation in the PCD process. The specific relationships between nucleus and cytoplasm in the developing endosperm cells and the morphological changes of nucleus in the endosperm PCD process were also discussed.展开更多
针对车联网中拒绝服务(denial of service,DoS)攻击难以防范且现有监督学习方法无法有效检测零日攻击的问题,提出了一种混合DoS攻击入侵检测系统.首先,对数据集进行预处理,提高数据的质量;其次,利用特征选择滤除冗余特征,旨在获得代表...针对车联网中拒绝服务(denial of service,DoS)攻击难以防范且现有监督学习方法无法有效检测零日攻击的问题,提出了一种混合DoS攻击入侵检测系统.首先,对数据集进行预处理,提高数据的质量;其次,利用特征选择滤除冗余特征,旨在获得代表性更强的特征;再次,采用集成学习方法将5种基于树结构的监督分类器堆叠集成用于检测已知DoS攻击;最后,提出了一种无监督异常检测方法,将卷积去噪自动编码器与注意力机制相结合来建立正常行为模型,用于检测堆叠集成模型漏报的未知DoS攻击.实验结果表明,对于已知DoS攻击检测,所提系统在Car-Hacking数据集和CICIDS2017数据集上的检测准确率分别为100%和99.967%;对于未知DoS攻击检测,所提系统在上述两个数据集上的检测准确率分别为100%和83.953%,并且在两个数据集上的平均测试时间分别为0.072 ms和0.157 ms,验证了所提系统的有效性和可行性.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.92582204,No.62577007,and No.62177003the Fundamental Research Funds for the Central Universities under Grant No.JKF-2025011975129.
文摘Online programming platforms are popular in programming education.However,there has been no research investigating students’real opinions and expectations of the error feedback mechanisms,leaving educators without a solid data foundation when attempting to improve the error feedback mechanisms.This paper makes a survey of 834 students across various programming courses and investigates student perceptions of error feedback mechanisms on online programming platforms.It explores the effectiveness of existing feedback,student satisfaction,and preferences for potential improvements,focusing on automatic error localization and program repair mechanisms.Results reveal a significant portion of students are dissatisfied with current feedback due to its limited informativeness.Students also express a clear demand for stronger feedback mechanisms,such as error localization and repair hints.Nevertheless,they prefer feedback that subtly guides them toward solutions,rather than providing direct and explicit answers,valuing the opportunity to enhance their debugging skills.The findings suggest a need for balanced,educational-focused feedback mechanisms that aid learning while promoting independent problem-solving.
基金financially supported by Ministerio de Ciencia e Innovación projects SAF2017-82736-C2-1-R to MTMFin Universidad Autónoma de Madrid and by Fundación Universidad Francisco de Vitoria to JS+2 种基金a predoctoral scholarship from Fundación Universidad Francisco de Vitoriafinancial support from a 6-month contract from Universidad Autónoma de Madrida 3-month contract from the School of Medicine of Universidad Francisco de Vitoria。
文摘Every year, around the world, between 250,000 and 500,000 people suffer a spinal cord injury(SCI). SCI is a devastating medical condition that arises from trauma or disease-induced damage to the spinal cord, disrupting the neural connections that allow communication between the brain and the rest of the body, which results in varying degrees of motor and sensory impairment. Disconnection in the spinal tracts is an irreversible condition owing to the poor capacity for spontaneous axonal regeneration in the affected neurons.
基金The National Natural Science Foundation of China[72174184]provided policy and financialsupport for this research.
文摘Objectives This study aimed to evaluate the effectiveness of the stepped self-care program on the self-care,self-efficacy,and quality of life of stroke survivors.Methods This quasi-experimental study allocated 110 stroke survivors from two neurology wards into an intervention group(n=55)who received the stepped self-care program and a control group(n=55)who received usual care from June to December 2023.The Self-Care of Stroke Inventory,Stroke Self-Efficacy Questionnaire,and the short version of the Stroke Specific Quality of Life Scale were administered at baseline(T0),immediately post-intervention(T_(1)),and at 1-month(T_(2))and 3-month(T_(3))follow-ups.Data were analyzed using repeated measures analyses of variance,and generalized estimating equations.Results A total of 48 participants in the intervention group and 50 participants in the control group completed the study.No statistically significant differences were observed at T0 in any of the measured indicators(all P>0.05).The study showed significant group,time,and group×time interaction effects across the assessed outcomes(all P<0.05).Follow-up between-group comparisons at T_(1),T_(2),and T_(3) indicated that the intervention group had significantly higher scores in self-care maintenance,self-care monitoring,self-care management,self-efficacy,and quality of life than the control group(all P<0.001).Conclusions The stepped self-care program significantly improved self-care behaviors,self-efficacy,and quality of life among stroke survivors.These findings support the broader implementation of this approach in post-discharge home self-care.
基金supported by the National Natural Science Foundation of China(82174513)Fundamental Research Funds for the Central Public Welfare Research Institutes(ZZ-JQ2023003).
文摘To systematically elucidate the central role of the cardiac autonomic nervous system(ANS)in maintaining cardiovascular homeostasis,analyze the pathological mechanisms underlying its dysregulation,integrate multidisciplinary research findings from the U.S.stimulating peripheral nerves to alleviate disease symptoms(SPARC)program,and evaluate the unique advantages and current limitations of acupuncture in modulating cardiac ANS function,ultimately proposing novel strategies for the prevention and treatment of cardiovascular diseases.A systematic literature review was conducted to synthesize current knowledge on the fundamental regulatory mechanisms of the cardiac ANS,the SPARC program's innovative contributions to neuroanatomy and neural pathway mapping,as well as clinical and experimental evidence supporting acupuncture's modulation of the ANS.The SPARC program has made significant progress in elucidating the anatomical organization and neural circuitry of the cardiac ANS through interdisciplinary collaboration,offering novel insights and methodological frameworks for studying cardiac autonomic regulation.Acupuncture,as a cornerstone of traditional medicine,has demonstrated both specificity and multi-target regulatory effects on the cardiac ANS through clinical and experimental studies.However,challenges remain,including an incomplete mechanistic understanding,technical limitations in research methodologies,and difficulties in translating findings into clinical practice.Future research on acupuncture should build upon its inherent strengths while advancing its integration with modern scientific and technological approaches.Strengthening interdisciplinary collaboration and leveraging artificial intelligence can open new frontiers in mechanistic exploration and technological innovation.These efforts will facilitate the internationalization of acupuncture research and contribute innovative perspectives and therapeutic strategies for cardiovascular disease prevention and treatment.
基金Supported by the National Natural Science Foundation of China(Grant Nos.12571317 and 12071133).
文摘In this paper,we study a class of Linear Fractional Programming on a nonempty bounded set,called the Problem(LFP),and design a branch and bound algorithm to find the global optimal solution of the problem(LFP).First,we convert the problem(LFP)to the equivalent problem(EP2).Secondly,by applying the linear relaxation technique to the problem(EP2),the linear relaxation programming problem(LRP2Y)was obtained.Then,the overall framework of the algorithm is given,and the convergence and complexity of the algorithm are analyzed.Finally,experimental results are listed to illustrate the effectiveness of the algorithm.
基金support from the National Natural Science Foundation of China(No.12002372)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2022QNRC001)the Natural Science Foundation of Hunan Province,China(No.2021JJ40674)。
文摘The operational demands of a wide range significantly exacerbate combustion instability issues within ramjet combustor.To suppress combustion oscillations,an open-loop control system utilizing Linear Genetic Programming(LGP)has been developed for a full-scale annular ramjet combustor.The LGP is used to generate control laws that include multi-frequency forcing.These laws are then transformed into square waves to actuate the solenoid valve,which modulates the kerosene supply for open-loop control.The results show that the duty cycle has little effect on instability amplitude,whereas an increase in frequency leads to a remarked reduction in combustion amplitude.After five generations evolvements,the pressure amplitude is reduced by 40.6% under the optimal control law generated by LGP.Furthermore,the machine learning process is depicted using a proximity map of control law similarity,with the search pathway visualized by the steepest descent.All individuals go forward to the upper left corner of the map with the evolution process,terminating at the optimal individual of the fifth generation.
文摘Instrumental and expert assessments were used to assess the effect of massage on facial skin blood perfusion,as well as the effects of the long-term use of the two skin health programs on the water content of the stratum corneum,F4,L^(*),dermal and epidermal thickness and density,facial wrinkles,and so on.Sixty healthy Chinese women were selected as the study subjects,which were subsequently divided into G1 non-massage group and G2 massage group.The results show that massage can increase the blood perfusion of facial skin.Group G2 solution is found to be more effective in improving the skin structural barrier(epidermal density),skin elasticity,firmness(dermal thickness)and forehead wrinkles.
文摘Aiming at the problem of innovative talent training in the industry field in characteristic software colleges,combined with the actual situation of Software College of Northeastern University,this paper analyzes the construction requirements of characteristic talent training mode and training scheme,puts forward the reform of characteristic software innovative talent training scheme integrating production and education,and takes the characteristic direction of financial technology as an example to introduce the curriculum construction based on industry-education integration and school-enterprise cooperation.
基金financially supported by the Natural Science Foundation of Jiangsu Province (No.BK20200709)the Natural Science Foundation of China (Nos.62288102,32201127 and 82270113)+2 种基金the Natural Science Foundation of Guangdong Province (No.2023A1515011386)the Natural Science Foundation of the Jiangsu Higher Education Institutes (No.20KJB430031)the startup fund from Nanjing Tech University,and Disciplinary Fund of School of Pharmaceutical Sciences (2024)。
文摘The field of nanomedicine has been revolutionized by the concept of immunogenic cell death(ICD)-enhanced cancer therapy,which holds immense promise for the efficient treatment of cancer.However,precise delivery of ICD inducer is severely hindered by complex biological barriers.How to design and build intelligent nanoplatform for adaptive and dynamic cancer therapy remains a big challenge.Herein,this article presents the design and preparation of CD44-targeting and ZIF-8 gated gold nanocage(Au@ZH) for programmed delivery of the 1,2-diaminocyclohexane-Pt(Ⅱ)(DACHPt) as ICD inducer.After actively targeting the CD44 on the surface of 4T1 tumor cell,this Pt-Au@ZH can be effectively endocytosed by the 4T1 cell and release the DACHPt in tumor acidic environment,resulting in ICD effect and superior antitumor efficacy both in vitro and in vivo in the presence of mild 808 nm laser irradiation.By integration of internal and external stimuli intelligently,this programmed nanoplatform is poised to become a cornerstone in the pursuit of effective and targeted cancer therapy in the foreseeable future.
基金supported by the National Natural Sci‐ence Foundation of China(Grant No.62306325)。
文摘During the use of robotics in applications such as antiterrorism or combat,a motion-constrained pursuer vehicle,such as a Dubins unmanned surface vehicle(USV),must get close enough(within a prescribed zero or positive distance)to a moving target as quickly as possible,resulting in the extended minimum-time intercept problem(EMTIP).Existing research has primarily focused on the zero-distance intercept problem,MTIP,establishing the necessary or sufficient conditions for MTIP optimality,and utilizing analytic algorithms,such as root-finding algorithms,to calculate the optimal solutions.However,these approaches depend heavily on the properties of the analytic algorithm,making them inapplicable when problem settings change,such as in the case of a positive effective range or complicated target motions outside uniform rectilinear motion.In this study,an approach employing a high-accuracy and quality-guaranteed mixed-integer piecewise-linear program(QG-PWL)is proposed for the EMTIP.This program can accommodate different effective interception ranges and complicated target motions(variable velocity or complicated trajectories).The high accuracy and quality guarantees of QG-PWL originate from elegant strategies such as piecewise linearization and other developed operation strategies.The approximate error in the intercept path length is proved to be bounded to h^(2)/(4√2),where h is the piecewise length.
基金supported by the National Natural Science Foundation of China(Nos.52075516,61927814,62325507,and 52122511)the National Key Research and Development Program of China(No.2021YFF0502700)+2 种基金the Major Scientific and Technological Projects in Anhui Province(202103a05020005,202203a05020014)the Students’Innovation and Entrepreneurship Foundation of USTC(CY2022G09)the Hefei Municipal Natural Science Foundation(No.HZR2450)。
文摘Programmable/reprogrammable magneto-responsive composites(MRCs)are highly desirable for applications in soft robotics,morphable actuators,and biomedical devices due to their capabilities of undergoing reversible,complex,untethered,and rapid deformations.However,current MRC-based devices primarily rely on soft matrices,which revert to their original shapes and cease functioning when external magnetic fields are removed.Moreover,their magnetization programming,deformations,and functioning need to alternate between encoding and actuation platforms,limiting the adaptability and efficiency.Here,we present a reprogrammable magnetic shape-memory composite(RM-SMC)integrating a shape-memory polymer(SMP)skeleton with phase-transition magnetic microcapsules.High-intensity laser melts microcapsules for magnetic realignment under programmed fields,while low-intensity laser softens SMP for structural reconfiguration without compromising integrity.This dual-laser strategy facilitates in situ magnetization programming,shape morphing,and function execution within a single material system.Our innovative approach enables unique applications,including omnidirectional multi-degree-of-freedom actuators that can activate light switches,solar trackers that optimize energy capture,and adaptive impellers that modulate fluid pumping.By eliminating platform alternation and enabling shape/function retention post-actuation,the RM-SMC platform overcomes critical limitations in conventional MRCs,establishing a paradigm for multifunctional devices requiring persistent configuration control and field-independent operation.
基金supported in part by Shanghai Natural Science Foundation(24ZR1454700)the National Natural Science Foundation of China(62503331,62533016,62573279,62173231,62203288)Shanghai Pujiang Program(23PJD033)。
文摘In this paper,a security defense issue is investigated for networked control systems susceptible to stochastic denial of service(DoS) attacks by using the sliding mode control method.To utilize network communication resources more effectively,a novel adaptive event-triggered(AET) mechanism is introduced,whose triggering coefficient can be adaptively adjusted according to the evolution trend of system states.Differing from existing event-triggered(ET) mechanisms,the proposed one demonstrates exceptional relevance and flexibility.It is closely related to attack probability,and its triggering coefficient dynamically adjusts depending on the presence or absence of an attack.To leverage attacker information more effectively,a switching-like sliding mode security controller is designed,which can autonomously select different controller gains based on the sliding function representing the attack situation.Sufficient conditions for the existence of the switching-like sliding mode secure controller are presented to ensure the stochastic stability of the system and the reachability of the sliding surface.Compared with existing time-invariant control strategies within the triggered interval,more resilient defense performance can be expected since the correlation with attack information is established in both the proposed AET scheme and the control strategy.Finally,a simulation example is conducted to verify the effectiveness and feasibility of the proposed security control method.
文摘Ultrastructural features of nucleus degradation during programmed cell death (PCD) of starchy endosperm cells in rice ( Oryza sativa L.) were observed using transmission electron microscopy. Several distinct morphological features of PCD have been found in the developing starchy endosperm cells, e.g. nucleus deformation, chromatin condensation, nuclear envelope disruption, and nuclear matrix leakage. DNA ladder displayed a smear of large DNA fragments from nucleus and evident bands of small DNA fragments (140-180 bp) from both nucleus and cytoplasm. In contrast with the rapid nucleus degradation, cell organelles in cytoplasm, such as rough endoplasmic reticulum, amyloplast, and mitochondrion, maintained their metabolic functions for a longer time. Seed reserves were continually synthesized and accumulated in the starchy endosperm cells despite the nucleus degradation during the PCD process. These results suggest that starchy endosperm cells remain active during reserve material synthesis and accumulation in the PCD process. The specific relationships between nucleus and cytoplasm in the developing endosperm cells and the morphological changes of nucleus in the endosperm PCD process were also discussed.
文摘针对车联网中拒绝服务(denial of service,DoS)攻击难以防范且现有监督学习方法无法有效检测零日攻击的问题,提出了一种混合DoS攻击入侵检测系统.首先,对数据集进行预处理,提高数据的质量;其次,利用特征选择滤除冗余特征,旨在获得代表性更强的特征;再次,采用集成学习方法将5种基于树结构的监督分类器堆叠集成用于检测已知DoS攻击;最后,提出了一种无监督异常检测方法,将卷积去噪自动编码器与注意力机制相结合来建立正常行为模型,用于检测堆叠集成模型漏报的未知DoS攻击.实验结果表明,对于已知DoS攻击检测,所提系统在Car-Hacking数据集和CICIDS2017数据集上的检测准确率分别为100%和99.967%;对于未知DoS攻击检测,所提系统在上述两个数据集上的检测准确率分别为100%和83.953%,并且在两个数据集上的平均测试时间分别为0.072 ms和0.157 ms,验证了所提系统的有效性和可行性.
