It can be seen from the calculation that the vulnerable area along China's coast in which the elevation is less than 5 m, is 143 900 km2, accounting for about 11. 3% of the total area of the 11 coastal provinces, ...It can be seen from the calculation that the vulnerable area along China's coast in which the elevation is less than 5 m, is 143 900 km2, accounting for about 11. 3% of the total area of the 11 coastal provinces, municipalities and autonomous regions. These areas are threatened to varying extent by sea level rise. According to prediction, the relative sea level rise (including global sea level rise caused by climate change and local relative as level rise caused by vertical crust movement and ground subsidence) along China's coast will be 4～16 cm by the year 2030 with the optimum estimated value of 6～14cm. It will be 9～26 cm by the year 2050 with the optimum estimated value of 12-23 cm. And it will be 31-74 cm by the year 2100 with the optimum estimated value of 47～65 cm. The calcuation result shows that the percentage of the cost for up-grading (heightening and consolidating) sea dykes/walls in adaptation strategy in the losses of submerged areas varies from area to area: 6. 9% in the Zhujiang (Pearl) River Deta, 1. 3% ～24. 6% in the Changjiang (Yangtze) River Delta, and 0. 9%～2. 0% in the Huanghe River Delta.展开更多
This paper reviews assessment of climate change impacts on economy, society and ecological environment in the coastal areas of South China based on published literatures; it also proposes suitable adaptation strategie...This paper reviews assessment of climate change impacts on economy, society and ecological environment in the coastal areas of South China based on published literatures; it also proposes suitable adaptation strategies and counter- measures. Review shows that climate change has resulted in sea level rise in the coastal areas of South China, increasing the occurrence and intensity of storm surges, aggravating the influence of saltwater intrusion, coastal erosion, urban drainage and flood control, threatening the coastal facility and infrastructures, inundating lowland areas, offsetting mudflat silting, and degrading mangroves and corm reef ecosystem. Therefore, in order to reduce the adverse effects of climate change and to support the sustainable development in the coastal areas of South China, it is critical to improve the monitoring and early warning system, enhance prevention criteria, fortify coastal protection engineering, strengthen saltwater prevention, and reinforce the ecological restoration and protection.展开更多
This article examines the effects of climate change on archaeological sites, using as a case study the archaeological site of Ancient Messene in Greece, and proposes an integrated adaptation strategy. In order to dete...This article examines the effects of climate change on archaeological sites, using as a case study the archaeological site of Ancient Messene in Greece, and proposes an integrated adaptation strategy. In order to determine the site’s most significant risks, a climate data analysis was conducted, taking into account three different climate emission scenarios (Representative Concentration Pathways) and two future periods (2031-2060, 2071-2100). The Intergovernmental Panel on Climate Change (IPCC) vulnerability assessment methodology was adopted to assess the vulnerability of the archaeological site to the effects of climate change. This is the first time such a methodology has been followed in Greece. The analysis revealed that the site’s critical hazards are fire, desertification, and flooding. The geographical location of the site in an intensely dry microclimate and the lack of safe and functional electromechanical and road infrastructure increase its vulnerability. The materials of the monuments are indirectly and directly impacted by climate change, whereas the vegetation is negatively impacted by the frequency of extreme events, especially wildfires. Based on the analysis results, a five-axis adaptation strategy was developed.展开更多
[Objective]The aim was to test the reliability and validity of questionnaire on the adaptation strategy of cryosphere changes in arid inland river basin.[Method]A questionnaire on'the adaptation strategy of cryosp...[Objective]The aim was to test the reliability and validity of questionnaire on the adaptation strategy of cryosphere changes in arid inland river basin.[Method]A questionnaire on'the adaptation strategy of cryosphere changes in arid inland river basin'was carried out in Urumchi River basin and Aksu River basin,and its reliability and validity were tested by means of statistical method,so as to investigate the stability and accuracy of questionnaire.[Result]Reliability analysis of questionnaire showed that the split-half reliability coefficient of questionnaire in Urumchi River basin and Aksu River basin was 0.729 and 0.750,respectively,and Cronbach’sαreliability coefficient was 0.613 and 0.616,respectively,which revealed that the questionnaire had good equivalence and internal consistency which reflected good reliability and stability.According to validity analysis on questionnaire,there was significant correlation between the score of most questions and questionnaire,and it indicated that questionnaire had high content validity.There were 8 common factors collected from 26 questions,which were summarized as agricultural planting,agricultural water conservation,life satisfaction,cultivated land variation,social integration sense,climate and cryosphere changes,capital input improved by environment and family economic condition,respectively.Meanwhile,the contribution rate of various questions in corresponding indexes was higher,and reflected structure was in full accord with questionnaire content,which revealed that questionnaire owned good construct validity.[Conclusion]With higher stability and accuracy,the questionnaire could determine the desired topic and content and was suitable for the study on the perception of common people and choices of adaptive strategy under cryosphere changes in arid inland river basin in northwestern China.展开更多
Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is rel...Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is relatively unstudied in the Canadian Prairie. This study compared three alternative beef herd management strategies in dealing with climate extreme events under reference climate scenario of 1971-2000 and the future scenario of 2041-2070. The study used farm simulation model that integrated the model of cattle herd simulation, pasture model, crop simulation model combined with models of economic decisions. Purchasing feed and maintaining herd size is preferred option in dealing with drought Changes in management such as early weaning combined with limit feeding strategies reduce the feed demand and also reduce the financial burden during the years of extreme event, but it has severe negative consequences on amount of slaughter cattle sold. Cull herd strategy not only reduces feed demand but also increases income from sell of herd during the year/s of extreme event, but it severely impacts the farm＇s long term output supply potential. However, expansion of existing agriculture risk management policy to cover climate risk in beef production is necessary to support farmers in the year/s to extreme events.展开更多
Trade-offs have long been recognized as a crucial ecological strategy for plant species in response to environmental stresses and disturbances.However,it remains unclear whether trade-offs exist among different struct...Trade-offs have long been recognized as a crucial ecological strategy for plant species in response to environmental stresses and disturbances.However,it remains unclear whether trade-offs exist among different structures(or functions)of clonal plants in response to aeolian activities in sandy environments.We examined the growth(reproductive vs.vegetative),reproduction(sexual vs.asexual),and bud bank(tiller buds and rhizome buds,representing vertical and horizontal growth potential)characteristics of two dominant rhizomatous grasses(Psammochloa villosa and Phragmites australis)in the arid sand dunes of northwestern China.Our results showed that these two rhizomatous clonal species exhibited significant trade-offs in their adaptation strategies in response to changes in sand burial depth.Specifically,as sand burial depth increased,the clonal species tended to reduce their reproductive growth,sexual reproductive capacity,and horizontal growth potential,as evidenced by reductions in reproductive ramet number and proportion,panicles number,biomass,and their proportions,as well as rhizome bud number,biomass,and their proportions.Conversely,they increased vegetative growth,reproduction,and vertical growth potential,as evidenced by enhancements in vegetative ramet number and proportion,belowground bud number,biomass,and their proportions,and in tiller bud number,biomass,and their proportions.Our study underscores the importance of trade-offs in the adaptation strategies of rhizomatous clonal species in sandy environments where drought stress and aeolian disturbance coexist.Those trade-offs could ensure the population persistence and stability of pioneering psammophytes in sand dunes,which should be considered during sand-fixing and vegetation restoration efforts in arid sand dunes.展开更多
This paper presents a vision-based navigation framework for micro air vehicles(MAVs)operating in confined warehouse environments.To address the trade-off between low localization accuracy in mapless methods and high c...This paper presents a vision-based navigation framework for micro air vehicles(MAVs)operating in confined warehouse environments.To address the trade-off between low localization accuracy in mapless methods and high computational demands in map-based approaches,the proposed system leverages topology-aware path guidance using monocular vision.Navigation is driven by a digital instruction format(DIF)that encodes both the path index and target junction,enabling autonomous navigation without environmental modifications.The framework comprises a cascaded perception-encoding-control pipeline.For structured paths,foreground pixel density trend analysis with sliding window smoothing for robust junction recognition,while lateral proportionalintegral-derivative(PID)control ensures accurate path tracking.For geometric trajectories,the control logic incorporates L-junction triggers,fixed-angle turns,and spatial yaw correction to accommodate sharp corners and curved segments.ROS-Gazebo simulations validate the method’s effectiveness,achieving up to 94.40%junction recognition accuracy(92.01%on average),trajectory tracking errors below 0.1 m,and terminal localization deviations under 0.2 m.These results validate the method’s accuracy,stability,and suitability for computationally constrained MAV platforms in warehouse automation.展开更多
This paper addresses the shortcomings of the Sparrow and Eagle Optimization Algorithm (SBOA) in terms of convergence accuracy, convergence speed, and susceptibility to local optima. To this end, an improved Sparrow an...This paper addresses the shortcomings of the Sparrow and Eagle Optimization Algorithm (SBOA) in terms of convergence accuracy, convergence speed, and susceptibility to local optima. To this end, an improved Sparrow and Eagle Optimization Algorithm (HS-SBOA) is proposed. Initially, the algorithm employs Iterative Mapping to generate an initial sparrow and eagle population, enhancing the diversity of the population during the global search phase. Subsequently, an adaptive weighting strategy is introduced during the exploration phase of the algorithm to achieve a balance between exploration and exploitation. Finally, to avoid the algorithm falling into local optima, a Cauchy mutation operation is applied to the current best individual. To validate the performance of the HS-SBOA algorithm, it was applied to the CEC2021 benchmark function set and three practical engineering problems, and compared with other optimization algorithms such as the Grey Wolf Optimization (GWO), Particle Swarm Optimization (PSO), and Whale Optimization Algorithm (WOA) to test the effectiveness of the improved algorithm. The simulation experimental results show that the HS-SBOA algorithm demonstrates significant advantages in terms of convergence speed and accuracy, thereby validating the effectiveness of its improved strategies.展开更多
A comprehensive analysis on the change of the total grain production and the temporal and spatial change of three main crops production（including wheat,maize and rice）,as well as the transfer trace of the center gra...A comprehensive analysis on the change of the total grain production and the temporal and spatial change of three main crops production（including wheat,maize and rice）,as well as the transfer trace of the center gravity of grain production in China were analyzed to reveal the overall developing trend of the grain production,explore the reasons and finally propose the corresponding suggestions and strategies to cope with the situation.展开更多
Drought stress is the main limiting plant growth factor in arid and semiarid regions.The Lanzhou lily(Lilium davidii var.unicolor)is the only sweet-tasting lily grown in these regions of China that offers highly edibl...Drought stress is the main limiting plant growth factor in arid and semiarid regions.The Lanzhou lily(Lilium davidii var.unicolor)is the only sweet-tasting lily grown in these regions of China that offers highly edible,medicinal,health,and ornamental value.The Tresor lily is an ornamental flower known for its strong resistance.Plants were grown under three different drought intensity treatments,namely,being watered at intervals of 5,15,and 25 d(either throughout the study or during specific growth stages).We measured the biomass,leaf area,photosynthetic response,chlorophyll content(SPAD value),and osmoregulation of both the Lanzhou lily and the Tresor lily(Lilium‘Tresor’).Additionally,we employed RNA sequencing(RNA-Seq)and qRT-PCR to investigate transcriptomic changes of the Lanzhou lily in response to drought stress.Results showed that under drought stress,the decreasing rate in the Lanzhou lily bulb weight was lower than the corresponding Tresor lily bulb rate;the net photosynthetic rate,transpiration rate,and stomatal conductance of the Lanzhou lily were all higher compared to the Tresor lily;osmoregulation constituents,such as glucose,fructose,sucrose,trehalose,and soluble sugar,in the Lanzhou lily were comparatively higher;PYL,NCED,and ERS genes were significantly expressed in the Lanzhou lily.Under moderate drought,the biosynthesis of flavonoids,circadian rhythms,and the tryptophan metabolism pathway of the Lanzhou lily were all significant.Under severe drought stress,fatty acid elongation,photosynthetic antenna protein,plant hormone signal transduction,flavone and flavonol biosynthesis,and the carotenoid biosynthesis pathway were all significant.The Lanzhou lily adapted to drought stress by coordinating its organs and the unique role of its bulb,regulating photosynthesis,increasing osmolyte content,activating circadian rhythms,signal transduction,fatty acid elongation metabolism,and phenylalanine and flavonoid metabolic pathways,which may collectively be the main adaptation strategy and mechanisms used by the Lanzhou lily under drought stress.展开更多
In the last decade, there has been increasing interest in climate change, pasture degradation and its driving forces, and innovations in nomadic pastoralism on the Tibetan Plateau. However, little is known of indigeno...In the last decade, there has been increasing interest in climate change, pasture degradation and its driving forces, and innovations in nomadic pastoralism on the Tibetan Plateau. However, little is known of indigenous strategies of adaptation to pasture degradation, which limits the effectiveness of adaptation strategies planned by local government. This paper analyzes nomads＇ strategies of adaptation to pasture degradation on the basis of a field survey of three townships of Dalag County in the source regions of the Yangtze and Yellow rivers. Pastures there have evidently degraded, with pastures in Wasai mainly in a state of slight or medium degradation and those in Manzhang and Jianshe in a state of medium or severe degradation. With the degradation of pasture, the grazing time is reduced, which af- fects the livelihoods of nomads. Although the Four-Package Project has commenced in this region, there is still severe fodder shortage in winter and spring. The traditional hay storage strategy does not work because of pasture degradation, and few nomads establish fenced and artificial pastures. Therefore, nomads have employed other strategies, such as renting pasture, providing supplementary feed, and diversifying their livelihoods. Local strategies taken by nomads can provide valuable insights into ecological restoration and livelihood improvement in the region and suggest changes to means promoted by local government. It is necessary to seek new means that combine the best aspects of nomadic pastoralism with modern stockbreeding technologies to help nomads adapt to pasture degeneration and improve their livelihoods.展开更多
This study reviews the impacts of climate change on human health and presents corresponding adaptation strategies in South China. The daily mean surface air temperatures above or below 26.4~C increase the death risk f...This study reviews the impacts of climate change on human health and presents corresponding adaptation strategies in South China. The daily mean surface air temperatures above or below 26.4~C increase the death risk for people in Guangzhou, especially the elderly are vulnerable to variations in temperature. Heat waves can cause insomnia, fatigue, clinical exacerbation, or death from heatstroke etc., while cold spells show increases in patients with fractures. During a cold spell period, the rates of both on-site emergency rescues and non-implementable rescues increase, and the risk of non-accidental deaths and respiratory disease deaths significantly rise as well. Both time series of hazy days and ozone concentrations have significant positive correlations with the number of patients with cardiovascular diseases. Both malaria and dengue fever reach higher altitudes and mountainous areas due to climate warming. Climate change is likely to bring stronger heat waves in the future, thereby increasing heat wave-related illnesses and deaths, particularly in the metropolitan areas of the Pearl River Delta. The projected increase of consecutive cold days in Guangdong province and parts of northern Guangxi province will affect residents＇ health in the future. The rising temperature exaggerates ozone pollution, but it is not clear whether climate change is aggravating or mitigating haze pollution. The transmission potential of malaria in South China will increase by 39%-140% and the transmission season will extend by 1 2 months with an air temperature increase of 1-2~C. By 2050, most areas in Hainan province are projected to convert from non-endemic dengue into endemic dengue areas. The aging population will cause more vulnerable people. To mitigate the adverse impacts of climate change on human health, sound and scientific adaptation strategies must be adopted in advance, such as strengthening the surveillance of epidemic diseases in potential transmission areas, conducting timely weather forecasting for human health, evaluating health vulnerability to climate change, improving environmental and health education, and strengthening hazard management and the cooperation between meteorological and health departments.展开更多
Climate change adaptation strategies provide a cushion for smallholder farmers,especially in subSaharan Africa against the risks posed by climate hazards such as droughts and floods.However,the decision-making process...Climate change adaptation strategies provide a cushion for smallholder farmers,especially in subSaharan Africa against the risks posed by climate hazards such as droughts and floods.However,the decision-making process in climate adaptation is complex.To better understand the dynamics of the process,we strive to answer this question:what are the potential trade-offs and synergies related to decision-making and implementation of climate adaptation strategies among smallholder farmers in sub-Saharan Africa region?A systematic literature review methodology was used through the Preferred Reporting Items for Systematic Review and Meta-Analysis(PRISMA)statement with the four-stage inclusion/exclusion criteria to identify the literature from selected databases(Scopus and Google Scholar).The climate adaptation strategies are organized into five broad categories(crop management,risk management,soil/land management,water management,and livestock management strategies).Evidence suggests that potential trade-offs may arise concerning added costs,additional labor requirements,and competition among objectives or available resources.The synergies,on the other hand,arise from implementing two or more adaptation strategies concurrently in respect of increased productivity,resilience,yield stability,sustainability,and environmental protection.Trade-offs and synergies may also differ among the various adaptation strategies with minimum/zero tillage,comparatively,presenting more tradeoffs.The development and promotion of low-cost adaptation strategies and complementary climate adaptation options that minimize the trade-offs and maximize the synergies are suggested.Skills and knowledge on proper implementation of climate change adaptation strategies are encouraged,especially at the local farm level.展开更多
The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors w...The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions, such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index （ACI） is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 12o heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.展开更多
Background:With the expansion of urban areas,the remnants of forested areas play a crucial role in preserving biodiversity in urban environments.This study aimed to explore the impact of spatiotemporal urban expansion...Background:With the expansion of urban areas,the remnants of forested areas play a crucial role in preserving biodiversity in urban environments.This study aimed to explore the impact of spatiotemporal urban expansion on the networks of leaf traits in woody plants within remnant forest patches,thereby enhancing our understanding of plant adaptive strategies and contributing to the conservation of urban biodiversity.Methods:Our study examined woody plants within 120 sample plots across 15 remnant forest patches in Guiyang,China.We constructed leaf trait networks (LTNs) based on 26 anatomical,structural,and compositional leaf traits and assessed the effects of the spatiotemporal dynamics of urban expansion on these LTNs.Results and conclusions:Our results indicate that shrubs within these patches have greater average path lengths and diameters than trees.With increasing urban expansion intensity,we observed a rise in the edge density of the LTN-shrubs.Additionally,modularity within the networks of shrubs decreased as road density and urban expansion intensity increased,and increases in the average path length and average clustering coefficient for shrubs were observed with a rise in the composite terrain complexity index.Notably,patches subjected to‘leapfrog’expansion exhibited greater average patch length and diameter than those experiencing edge growth.Stomatal traits were found to have high degree centrality within these networks,signifying their substantial contribution to multiple functions.In urban remnant forests,shrubs bolster their resilience to variable environmental pressures by augmenting the complexity of their leaf trait networks.展开更多
Unlike animals, plants cannot move away from unfavorable environments. Instead, they must continuously adjust their growth to external conditions. When the environment is favorable, plants sustain vigorous growth. Con...Unlike animals, plants cannot move away from unfavorable environments. Instead, they must continuously adjust their growth to external conditions. When the environment is favorable, plants sustain vigorous growth. Conversely, when challenged by drought, salinity, temperature extremes, or other stresses, they must rapidly suppress growth to conserve energy and minimize damage. This capacity to switch growth on or off in response to external cues represents one of the most successful adaptive strategies that enables plants to thrive worldwide. A central mediator of this growth suppression is the phytohormone abscisic acid(ABA). Abscisic acid plays pivotal roles in stomata closure, germination inhibition, and root development modulation, thereby orchestrating defense responses under abiotic stresses(e.g., Chen et al., 2020, for a review). For this reason, ABA is often referred to as the“stress hormone” of plants. However,growth arrest is only half of the story. Once environmental conditions improve, plants must promptly resume growth to recover and compete effectively. For survival, the decision of whether“to grow or not to grow” is critical, and yet, the molecular mechanisms that enable plants to toggle this switch have long remained elusive.展开更多
Engineering optimization problems are often characterized by high dimensionality,constraints,and complex,multimodal landscapes.Traditional deterministic methods frequently struggle under such conditions,prompting incr...Engineering optimization problems are often characterized by high dimensionality,constraints,and complex,multimodal landscapes.Traditional deterministic methods frequently struggle under such conditions,prompting increased interest in swarm intelligence algorithms.Among these,the Cuckoo Search(CS)algorithm stands out for its promising global search capabilities.However,it often suffers from premature convergence when tackling complex problems.To address this limitation,this paper proposes a Grouped Dynamic Adaptive CS(GDACS)algorithm.Theenhancements incorporated intoGDACS can be summarized into two key aspects.Firstly,a chaotic map is employed to generate initial solutions,leveraging the inherent randomness of chaotic sequences to ensure a more uniform distribution across the search space and enhance population diversity from the outset.Secondly,Cauchy and Levy strategies replace the standard CS population update.This strategy involves evaluating the fitness of candidate solutions to dynamically group the population based on performance.Different step-size adaptation strategies are then applied to distinct groups,enabling an adaptive search mechanism that balances exploration and exploitation.Experiments were conducted on six benchmark functions and four constrained engineering design problems,and the results indicate that the proposed GDACS achieves good search efficiency and produces more accurate optimization results compared with other state-of-the-art algorithms.展开更多
Federated Learning(FL)protects data privacy through a distributed training mechanism,yet its decentralized nature also introduces new security vulnerabilities.Backdoor attacks inject malicious triggers into the global...Federated Learning(FL)protects data privacy through a distributed training mechanism,yet its decentralized nature also introduces new security vulnerabilities.Backdoor attacks inject malicious triggers into the global model through compromised updates,posing significant threats to model integrity and becoming a key focus in FL security.Existing backdoor attack methods typically embed triggers directly into original images and consider only data heterogeneity,resulting in limited stealth and adaptability.To address the heterogeneity of malicious client devices,this paper proposes a novel backdoor attack method named Capability-Adaptive Shadow Backdoor Attack(CASBA).By incorporating measurements of clients’computational and communication capabilities,CASBA employs a dynamic hierarchical attack strategy that adaptively aligns attack intensity with available resources.Furthermore,an improved deep convolutional generative adversarial network(DCGAN)is integrated into the attack pipeline to embed triggers without modifying original data,significantly enhancing stealthiness.Comparative experiments with Shadow Backdoor Attack(SBA)across multiple scenarios demonstrate that CASBA dynamically adjusts resource consumption based on device capabilities,reducing average memory usage per iteration by 5.8%.CASBA improves resource efficiency while keeping the drop in attack success rate within 3%.Additionally,the effectiveness of CASBA against three robust FL algorithms is also validated.展开更多
The Old Town of Corfu is an excellent example of a historic town and a World Heritage Site, distinguished by its authentic and unique character, as reflected in its Venetian-era fortifications and extensive historic b...The Old Town of Corfu is an excellent example of a historic town and a World Heritage Site, distinguished by its authentic and unique character, as reflected in its Venetian-era fortifications and extensive historic building stock. Simultaneously, the Old Town of Corfu is also a vibrant modern city vulnerable to various pressures, including climate change. This paper aims to evaluate the effects of climate change on this modern city monument, assess its vulnerability using the Intergovernmental Panel on Climate Change’s methodology, and develop a comprehensive set of adaptation proposals. The methodology of this paper is based on the analysis of climate data for the Old Town of Corfu, from which the assessment of the extreme weather events and climate changes that pose the greatest threat to the Old Town and the assessment of its vulnerability to these threats are derived. The dense geometrical characteristics of the city’s structure, the intense pathology observed in the materials and structures of the historic building stock, problems in the existing electromechanical infrastructure, and the poor management of issues such as increased tourism and heavy traffic congestion are the primary factors that make the Old Town of Corfu vulnerable to the effects of climate change.展开更多
Space-based Automatic Dependent Surveillance-Broadcast(ADS-B)technology can eliminate the blind spots of terrestrial ADS-B systems because of its global coverage capability.However,the space-based ADS-B system faces n...Space-based Automatic Dependent Surveillance-Broadcast(ADS-B)technology can eliminate the blind spots of terrestrial ADS-B systems because of its global coverage capability.However,the space-based ADS-B system faces new problems such as extremely low Signal-toNoise Ratio(SNR)and serious co-channel interference,which result in long update intervals.To minimize the position message update interval at an update probability of 95%with full coverage constraint,this paper presents an optimization model of digital multi-beamforming for space-based ADS-B.Then,a coevolution method DECCG_A&A is proposed to enhance the optimization efficiency by using an improved adaptive grouping strategy.The strategy is based on the locations of uncovered areas and the aircraft density under the coverage of each beam.Simulation results show that the update interval can be effectively controlled to be below 8 seconds compared with other existing methods,and DECCG_A&A is superior in convergence to the Genetic Algorithm(GA)as well as the coevolution algorithms using other grouping strategies.Overall,the proposed optimization model and method can significantly reduce the update interval,thus improving the surveillance performance of space-based ADS-B for air traffic control.展开更多
文摘It can be seen from the calculation that the vulnerable area along China's coast in which the elevation is less than 5 m, is 143 900 km2, accounting for about 11. 3% of the total area of the 11 coastal provinces, municipalities and autonomous regions. These areas are threatened to varying extent by sea level rise. According to prediction, the relative sea level rise (including global sea level rise caused by climate change and local relative as level rise caused by vertical crust movement and ground subsidence) along China's coast will be 4～16 cm by the year 2030 with the optimum estimated value of 6～14cm. It will be 9～26 cm by the year 2050 with the optimum estimated value of 12-23 cm. And it will be 31-74 cm by the year 2100 with the optimum estimated value of 47～65 cm. The calcuation result shows that the percentage of the cost for up-grading (heightening and consolidating) sea dykes/walls in adaptation strategy in the losses of submerged areas varies from area to area: 6. 9% in the Zhujiang (Pearl) River Deta, 1. 3% ～24. 6% in the Changjiang (Yangtze) River Delta, and 0. 9%～2. 0% in the Huanghe River Delta.
基金supported by the Special Climate Change Research Program of China Meteorological Administration(No.CCSF-09-11,CCSF2011-25,and CCSF201307)the Science and Technology Planning Project of Guangdong Province(No.2011A030200021)
文摘This paper reviews assessment of climate change impacts on economy, society and ecological environment in the coastal areas of South China based on published literatures; it also proposes suitable adaptation strategies and counter- measures. Review shows that climate change has resulted in sea level rise in the coastal areas of South China, increasing the occurrence and intensity of storm surges, aggravating the influence of saltwater intrusion, coastal erosion, urban drainage and flood control, threatening the coastal facility and infrastructures, inundating lowland areas, offsetting mudflat silting, and degrading mangroves and corm reef ecosystem. Therefore, in order to reduce the adverse effects of climate change and to support the sustainable development in the coastal areas of South China, it is critical to improve the monitoring and early warning system, enhance prevention criteria, fortify coastal protection engineering, strengthen saltwater prevention, and reinforce the ecological restoration and protection.
文摘This article examines the effects of climate change on archaeological sites, using as a case study the archaeological site of Ancient Messene in Greece, and proposes an integrated adaptation strategy. In order to determine the site’s most significant risks, a climate data analysis was conducted, taking into account three different climate emission scenarios (Representative Concentration Pathways) and two future periods (2031-2060, 2071-2100). The Intergovernmental Panel on Climate Change (IPCC) vulnerability assessment methodology was adopted to assess the vulnerability of the archaeological site to the effects of climate change. This is the first time such a methodology has been followed in Greece. The analysis revealed that the site’s critical hazards are fire, desertification, and flooding. The geographical location of the site in an intensely dry microclimate and the lack of safe and functional electromechanical and road infrastructure increase its vulnerability. The materials of the monuments are indirectly and directly impacted by climate change, whereas the vegetation is negatively impacted by the frequency of extreme events, especially wildfires. Based on the analysis results, a five-axis adaptation strategy was developed.
基金Supported by Major State Basic Research Development Program of China(2007CB411507)Open Foundation Project of State Key Laboratory of Cryospheric Sciences,Chinese Academy of Sciences(SKLCS08-04)
文摘[Objective]The aim was to test the reliability and validity of questionnaire on the adaptation strategy of cryosphere changes in arid inland river basin.[Method]A questionnaire on'the adaptation strategy of cryosphere changes in arid inland river basin'was carried out in Urumchi River basin and Aksu River basin,and its reliability and validity were tested by means of statistical method,so as to investigate the stability and accuracy of questionnaire.[Result]Reliability analysis of questionnaire showed that the split-half reliability coefficient of questionnaire in Urumchi River basin and Aksu River basin was 0.729 and 0.750,respectively,and Cronbach’sαreliability coefficient was 0.613 and 0.616,respectively,which revealed that the questionnaire had good equivalence and internal consistency which reflected good reliability and stability.According to validity analysis on questionnaire,there was significant correlation between the score of most questions and questionnaire,and it indicated that questionnaire had high content validity.There were 8 common factors collected from 26 questions,which were summarized as agricultural planting,agricultural water conservation,life satisfaction,cultivated land variation,social integration sense,climate and cryosphere changes,capital input improved by environment and family economic condition,respectively.Meanwhile,the contribution rate of various questions in corresponding indexes was higher,and reflected structure was in full accord with questionnaire content,which revealed that questionnaire owned good construct validity.[Conclusion]With higher stability and accuracy,the questionnaire could determine the desired topic and content and was suitable for the study on the perception of common people and choices of adaptive strategy under cryosphere changes in arid inland river basin in northwestern China.
文摘Economic impact of climate extremes on beef operation is expected to be significant due to its direct impact on feed production. Impact of such events on farm management and longer term farm financial situation is relatively unstudied in the Canadian Prairie. This study compared three alternative beef herd management strategies in dealing with climate extreme events under reference climate scenario of 1971-2000 and the future scenario of 2041-2070. The study used farm simulation model that integrated the model of cattle herd simulation, pasture model, crop simulation model combined with models of economic decisions. Purchasing feed and maintaining herd size is preferred option in dealing with drought Changes in management such as early weaning combined with limit feeding strategies reduce the feed demand and also reduce the financial burden during the years of extreme event, but it has severe negative consequences on amount of slaughter cattle sold. Cull herd strategy not only reduces feed demand but also increases income from sell of herd during the year/s of extreme event, but it severely impacts the farm＇s long term output supply potential. However, expansion of existing agriculture risk management policy to cover climate risk in beef production is necessary to support farmers in the year/s to extreme events.
基金supported by the National Natural Science Foundation of China(41877542)the Key Scientific and Technological Project of Henan Province(232102320245).
文摘Trade-offs have long been recognized as a crucial ecological strategy for plant species in response to environmental stresses and disturbances.However,it remains unclear whether trade-offs exist among different structures(or functions)of clonal plants in response to aeolian activities in sandy environments.We examined the growth(reproductive vs.vegetative),reproduction(sexual vs.asexual),and bud bank(tiller buds and rhizome buds,representing vertical and horizontal growth potential)characteristics of two dominant rhizomatous grasses(Psammochloa villosa and Phragmites australis)in the arid sand dunes of northwestern China.Our results showed that these two rhizomatous clonal species exhibited significant trade-offs in their adaptation strategies in response to changes in sand burial depth.Specifically,as sand burial depth increased,the clonal species tended to reduce their reproductive growth,sexual reproductive capacity,and horizontal growth potential,as evidenced by reductions in reproductive ramet number and proportion,panicles number,biomass,and their proportions,as well as rhizome bud number,biomass,and their proportions.Conversely,they increased vegetative growth,reproduction,and vertical growth potential,as evidenced by enhancements in vegetative ramet number and proportion,belowground bud number,biomass,and their proportions,and in tiller bud number,biomass,and their proportions.Our study underscores the importance of trade-offs in the adaptation strategies of rhizomatous clonal species in sandy environments where drought stress and aeolian disturbance coexist.Those trade-offs could ensure the population persistence and stability of pioneering psammophytes in sand dunes,which should be considered during sand-fixing and vegetation restoration efforts in arid sand dunes.
基金supported by the Fundamental Research Grant Scheme(FRGS)(No.FRGS/1/2024/TK04/USM/02/3)funded by the Malaysian Ministry of Higher Education(MOHE).
文摘This paper presents a vision-based navigation framework for micro air vehicles(MAVs)operating in confined warehouse environments.To address the trade-off between low localization accuracy in mapless methods and high computational demands in map-based approaches,the proposed system leverages topology-aware path guidance using monocular vision.Navigation is driven by a digital instruction format(DIF)that encodes both the path index and target junction,enabling autonomous navigation without environmental modifications.The framework comprises a cascaded perception-encoding-control pipeline.For structured paths,foreground pixel density trend analysis with sliding window smoothing for robust junction recognition,while lateral proportionalintegral-derivative(PID)control ensures accurate path tracking.For geometric trajectories,the control logic incorporates L-junction triggers,fixed-angle turns,and spatial yaw correction to accommodate sharp corners and curved segments.ROS-Gazebo simulations validate the method’s effectiveness,achieving up to 94.40%junction recognition accuracy(92.01%on average),trajectory tracking errors below 0.1 m,and terminal localization deviations under 0.2 m.These results validate the method’s accuracy,stability,and suitability for computationally constrained MAV platforms in warehouse automation.
文摘This paper addresses the shortcomings of the Sparrow and Eagle Optimization Algorithm (SBOA) in terms of convergence accuracy, convergence speed, and susceptibility to local optima. To this end, an improved Sparrow and Eagle Optimization Algorithm (HS-SBOA) is proposed. Initially, the algorithm employs Iterative Mapping to generate an initial sparrow and eagle population, enhancing the diversity of the population during the global search phase. Subsequently, an adaptive weighting strategy is introduced during the exploration phase of the algorithm to achieve a balance between exploration and exploitation. Finally, to avoid the algorithm falling into local optima, a Cauchy mutation operation is applied to the current best individual. To validate the performance of the HS-SBOA algorithm, it was applied to the CEC2021 benchmark function set and three practical engineering problems, and compared with other optimization algorithms such as the Grey Wolf Optimization (GWO), Particle Swarm Optimization (PSO), and Whale Optimization Algorithm (WOA) to test the effectiveness of the improved algorithm. The simulation experimental results show that the HS-SBOA algorithm demonstrates significant advantages in terms of convergence speed and accuracy, thereby validating the effectiveness of its improved strategies.
基金Supported by National Scientific and Technological Supporting Project(2006BAD20B05)~~
文摘A comprehensive analysis on the change of the total grain production and the temporal and spatial change of three main crops production（including wheat,maize and rice）,as well as the transfer trace of the center gravity of grain production in China were analyzed to reveal the overall developing trend of the grain production,explore the reasons and finally propose the corresponding suggestions and strategies to cope with the situation.
基金the Gansu Science and Technology Major Project(Grant No.182D2NA010)the Science and Technology Service Network Initiative of the Chinese Academy of Sciences(Grant No.KFJ-STS-QYZD-120)the Key R&D plan of the Ningxia Hui Autonomous Region(Grant No.2019BBF02018)for the funding they provided。
文摘Drought stress is the main limiting plant growth factor in arid and semiarid regions.The Lanzhou lily(Lilium davidii var.unicolor)is the only sweet-tasting lily grown in these regions of China that offers highly edible,medicinal,health,and ornamental value.The Tresor lily is an ornamental flower known for its strong resistance.Plants were grown under three different drought intensity treatments,namely,being watered at intervals of 5,15,and 25 d(either throughout the study or during specific growth stages).We measured the biomass,leaf area,photosynthetic response,chlorophyll content(SPAD value),and osmoregulation of both the Lanzhou lily and the Tresor lily(Lilium‘Tresor’).Additionally,we employed RNA sequencing(RNA-Seq)and qRT-PCR to investigate transcriptomic changes of the Lanzhou lily in response to drought stress.Results showed that under drought stress,the decreasing rate in the Lanzhou lily bulb weight was lower than the corresponding Tresor lily bulb rate;the net photosynthetic rate,transpiration rate,and stomatal conductance of the Lanzhou lily were all higher compared to the Tresor lily;osmoregulation constituents,such as glucose,fructose,sucrose,trehalose,and soluble sugar,in the Lanzhou lily were comparatively higher;PYL,NCED,and ERS genes were significantly expressed in the Lanzhou lily.Under moderate drought,the biosynthesis of flavonoids,circadian rhythms,and the tryptophan metabolism pathway of the Lanzhou lily were all significant.Under severe drought stress,fatty acid elongation,photosynthetic antenna protein,plant hormone signal transduction,flavone and flavonol biosynthesis,and the carotenoid biosynthesis pathway were all significant.The Lanzhou lily adapted to drought stress by coordinating its organs and the unique role of its bulb,regulating photosynthesis,increasing osmolyte content,activating circadian rhythms,signal transduction,fatty acid elongation metabolism,and phenylalanine and flavonoid metabolic pathways,which may collectively be the main adaptation strategy and mechanisms used by the Lanzhou lily under drought stress.
基金National Basic Research Program of China, No.2010CB951704 National Natural Science Foundation of China, No.41071066
文摘In the last decade, there has been increasing interest in climate change, pasture degradation and its driving forces, and innovations in nomadic pastoralism on the Tibetan Plateau. However, little is known of indigenous strategies of adaptation to pasture degradation, which limits the effectiveness of adaptation strategies planned by local government. This paper analyzes nomads＇ strategies of adaptation to pasture degradation on the basis of a field survey of three townships of Dalag County in the source regions of the Yangtze and Yellow rivers. Pastures there have evidently degraded, with pastures in Wasai mainly in a state of slight or medium degradation and those in Manzhang and Jianshe in a state of medium or severe degradation. With the degradation of pasture, the grazing time is reduced, which af- fects the livelihoods of nomads. Although the Four-Package Project has commenced in this region, there is still severe fodder shortage in winter and spring. The traditional hay storage strategy does not work because of pasture degradation, and few nomads establish fenced and artificial pastures. Therefore, nomads have employed other strategies, such as renting pasture, providing supplementary feed, and diversifying their livelihoods. Local strategies taken by nomads can provide valuable insights into ecological restoration and livelihood improvement in the region and suggest changes to means promoted by local government. It is necessary to seek new means that combine the best aspects of nomadic pastoralism with modern stockbreeding technologies to help nomads adapt to pasture degeneration and improve their livelihoods.
基金supported by the Special Climate Change Research Program of China Meteorological Ad-ministration(No.CCSF-09-11 and CCSF201307)by the Science and Technology Planning Project of Guang-dong province(No.2011A030200021)
文摘This study reviews the impacts of climate change on human health and presents corresponding adaptation strategies in South China. The daily mean surface air temperatures above or below 26.4~C increase the death risk for people in Guangzhou, especially the elderly are vulnerable to variations in temperature. Heat waves can cause insomnia, fatigue, clinical exacerbation, or death from heatstroke etc., while cold spells show increases in patients with fractures. During a cold spell period, the rates of both on-site emergency rescues and non-implementable rescues increase, and the risk of non-accidental deaths and respiratory disease deaths significantly rise as well. Both time series of hazy days and ozone concentrations have significant positive correlations with the number of patients with cardiovascular diseases. Both malaria and dengue fever reach higher altitudes and mountainous areas due to climate warming. Climate change is likely to bring stronger heat waves in the future, thereby increasing heat wave-related illnesses and deaths, particularly in the metropolitan areas of the Pearl River Delta. The projected increase of consecutive cold days in Guangdong province and parts of northern Guangxi province will affect residents＇ health in the future. The rising temperature exaggerates ozone pollution, but it is not clear whether climate change is aggravating or mitigating haze pollution. The transmission potential of malaria in South China will increase by 39%-140% and the transmission season will extend by 1 2 months with an air temperature increase of 1-2~C. By 2050, most areas in Hainan province are projected to convert from non-endemic dengue into endemic dengue areas. The aging population will cause more vulnerable people. To mitigate the adverse impacts of climate change on human health, sound and scientific adaptation strategies must be adopted in advance, such as strengthening the surveillance of epidemic diseases in potential transmission areas, conducting timely weather forecasting for human health, evaluating health vulnerability to climate change, improving environmental and health education, and strengthening hazard management and the cooperation between meteorological and health departments.
文摘Climate change adaptation strategies provide a cushion for smallholder farmers,especially in subSaharan Africa against the risks posed by climate hazards such as droughts and floods.However,the decision-making process in climate adaptation is complex.To better understand the dynamics of the process,we strive to answer this question:what are the potential trade-offs and synergies related to decision-making and implementation of climate adaptation strategies among smallholder farmers in sub-Saharan Africa region?A systematic literature review methodology was used through the Preferred Reporting Items for Systematic Review and Meta-Analysis(PRISMA)statement with the four-stage inclusion/exclusion criteria to identify the literature from selected databases(Scopus and Google Scholar).The climate adaptation strategies are organized into five broad categories(crop management,risk management,soil/land management,water management,and livestock management strategies).Evidence suggests that potential trade-offs may arise concerning added costs,additional labor requirements,and competition among objectives or available resources.The synergies,on the other hand,arise from implementing two or more adaptation strategies concurrently in respect of increased productivity,resilience,yield stability,sustainability,and environmental protection.Trade-offs and synergies may also differ among the various adaptation strategies with minimum/zero tillage,comparatively,presenting more tradeoffs.The development and promotion of low-cost adaptation strategies and complementary climate adaptation options that minimize the trade-offs and maximize the synergies are suggested.Skills and knowledge on proper implementation of climate change adaptation strategies are encouraged,especially at the local farm level.
文摘The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions, such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index （ACI） is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 12o heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.
基金funded by the National Natural Science Foundation of China (No.32360418)the Guizhou Provincial Basic Research Program (Natural Science)(No.QianKeHeJiChu-ZK[2024]YiBan022)。
文摘Background:With the expansion of urban areas,the remnants of forested areas play a crucial role in preserving biodiversity in urban environments.This study aimed to explore the impact of spatiotemporal urban expansion on the networks of leaf traits in woody plants within remnant forest patches,thereby enhancing our understanding of plant adaptive strategies and contributing to the conservation of urban biodiversity.Methods:Our study examined woody plants within 120 sample plots across 15 remnant forest patches in Guiyang,China.We constructed leaf trait networks (LTNs) based on 26 anatomical,structural,and compositional leaf traits and assessed the effects of the spatiotemporal dynamics of urban expansion on these LTNs.Results and conclusions:Our results indicate that shrubs within these patches have greater average path lengths and diameters than trees.With increasing urban expansion intensity,we observed a rise in the edge density of the LTN-shrubs.Additionally,modularity within the networks of shrubs decreased as road density and urban expansion intensity increased,and increases in the average path length and average clustering coefficient for shrubs were observed with a rise in the composite terrain complexity index.Notably,patches subjected to‘leapfrog’expansion exhibited greater average patch length and diameter than those experiencing edge growth.Stomatal traits were found to have high degree centrality within these networks,signifying their substantial contribution to multiple functions.In urban remnant forests,shrubs bolster their resilience to variable environmental pressures by augmenting the complexity of their leaf trait networks.
基金supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science(JSPS KAKENHI)[Grant numbers JP22H02294 to M.M.,JP22K05365 and JP23K18058 to S.K.]by the commissioned research fund provided by F-REI(JPFR25020105)to S.K。
文摘Unlike animals, plants cannot move away from unfavorable environments. Instead, they must continuously adjust their growth to external conditions. When the environment is favorable, plants sustain vigorous growth. Conversely, when challenged by drought, salinity, temperature extremes, or other stresses, they must rapidly suppress growth to conserve energy and minimize damage. This capacity to switch growth on or off in response to external cues represents one of the most successful adaptive strategies that enables plants to thrive worldwide. A central mediator of this growth suppression is the phytohormone abscisic acid(ABA). Abscisic acid plays pivotal roles in stomata closure, germination inhibition, and root development modulation, thereby orchestrating defense responses under abiotic stresses(e.g., Chen et al., 2020, for a review). For this reason, ABA is often referred to as the“stress hormone” of plants. However,growth arrest is only half of the story. Once environmental conditions improve, plants must promptly resume growth to recover and compete effectively. For survival, the decision of whether“to grow or not to grow” is critical, and yet, the molecular mechanisms that enable plants to toggle this switch have long remained elusive.
基金supported in part by the Ministry of Higher Education Malaysia(MOHE)through Fundamental Research Grant Scheme(FRGS)Ref:FRGS/1/2024/ICT02/UTM/02/10,Vot.No:R.J130000.7828.5F748the Scientific Research Project of Education Department of Hunan Province(Nos.22B1046 and 24A0771).
文摘Engineering optimization problems are often characterized by high dimensionality,constraints,and complex,multimodal landscapes.Traditional deterministic methods frequently struggle under such conditions,prompting increased interest in swarm intelligence algorithms.Among these,the Cuckoo Search(CS)algorithm stands out for its promising global search capabilities.However,it often suffers from premature convergence when tackling complex problems.To address this limitation,this paper proposes a Grouped Dynamic Adaptive CS(GDACS)algorithm.Theenhancements incorporated intoGDACS can be summarized into two key aspects.Firstly,a chaotic map is employed to generate initial solutions,leveraging the inherent randomness of chaotic sequences to ensure a more uniform distribution across the search space and enhance population diversity from the outset.Secondly,Cauchy and Levy strategies replace the standard CS population update.This strategy involves evaluating the fitness of candidate solutions to dynamically group the population based on performance.Different step-size adaptation strategies are then applied to distinct groups,enabling an adaptive search mechanism that balances exploration and exploitation.Experiments were conducted on six benchmark functions and four constrained engineering design problems,and the results indicate that the proposed GDACS achieves good search efficiency and produces more accurate optimization results compared with other state-of-the-art algorithms.
基金supported by the National Natural Science Foundation of China(Grant No.62172123)the Key Research and Development Program of Heilongjiang Province,China(GrantNo.2022ZX01A36).
文摘Federated Learning(FL)protects data privacy through a distributed training mechanism,yet its decentralized nature also introduces new security vulnerabilities.Backdoor attacks inject malicious triggers into the global model through compromised updates,posing significant threats to model integrity and becoming a key focus in FL security.Existing backdoor attack methods typically embed triggers directly into original images and consider only data heterogeneity,resulting in limited stealth and adaptability.To address the heterogeneity of malicious client devices,this paper proposes a novel backdoor attack method named Capability-Adaptive Shadow Backdoor Attack(CASBA).By incorporating measurements of clients’computational and communication capabilities,CASBA employs a dynamic hierarchical attack strategy that adaptively aligns attack intensity with available resources.Furthermore,an improved deep convolutional generative adversarial network(DCGAN)is integrated into the attack pipeline to embed triggers without modifying original data,significantly enhancing stealthiness.Comparative experiments with Shadow Backdoor Attack(SBA)across multiple scenarios demonstrate that CASBA dynamically adjusts resource consumption based on device capabilities,reducing average memory usage per iteration by 5.8%.CASBA improves resource efficiency while keeping the drop in attack success rate within 3%.Additionally,the effectiveness of CASBA against three robust FL algorithms is also validated.
文摘The Old Town of Corfu is an excellent example of a historic town and a World Heritage Site, distinguished by its authentic and unique character, as reflected in its Venetian-era fortifications and extensive historic building stock. Simultaneously, the Old Town of Corfu is also a vibrant modern city vulnerable to various pressures, including climate change. This paper aims to evaluate the effects of climate change on this modern city monument, assess its vulnerability using the Intergovernmental Panel on Climate Change’s methodology, and develop a comprehensive set of adaptation proposals. The methodology of this paper is based on the analysis of climate data for the Old Town of Corfu, from which the assessment of the extreme weather events and climate changes that pose the greatest threat to the Old Town and the assessment of its vulnerability to these threats are derived. The dense geometrical characteristics of the city’s structure, the intense pathology observed in the materials and structures of the historic building stock, problems in the existing electromechanical infrastructure, and the poor management of issues such as increased tourism and heavy traffic congestion are the primary factors that make the Old Town of Corfu vulnerable to the effects of climate change.
文摘Space-based Automatic Dependent Surveillance-Broadcast(ADS-B)technology can eliminate the blind spots of terrestrial ADS-B systems because of its global coverage capability.However,the space-based ADS-B system faces new problems such as extremely low Signal-toNoise Ratio(SNR)and serious co-channel interference,which result in long update intervals.To minimize the position message update interval at an update probability of 95%with full coverage constraint,this paper presents an optimization model of digital multi-beamforming for space-based ADS-B.Then,a coevolution method DECCG_A&A is proposed to enhance the optimization efficiency by using an improved adaptive grouping strategy.The strategy is based on the locations of uncovered areas and the aircraft density under the coverage of each beam.Simulation results show that the update interval can be effectively controlled to be below 8 seconds compared with other existing methods,and DECCG_A&A is superior in convergence to the Genetic Algorithm(GA)as well as the coevolution algorithms using other grouping strategies.Overall,the proposed optimization model and method can significantly reduce the update interval,thus improving the surveillance performance of space-based ADS-B for air traffic control.
