The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency.Therefore,the wind-resistant fuzzy comfortability of a super-high tower ...The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency.Therefore,the wind-resistant fuzzy comfortability of a super-high tower crane in the Ma’anshan Yangtze River(MYR)Bridge site is analyzed in this paper.First,the membership function model that represents fuzzy comfortability is introduced in the probability density evolution method(PDEM).Second,based on Fechner’s law,the membership function curves are constructed according to three acceleration thresholds in ISO 2631.Then,the fuzzy comfortability for the super-high tower crane under stochastic wind loads is assessed on the basis of different cut-set levelsλ.Results show that the comfortability is over 0.9 under the required maximum operating wind velocity.The low sensitivity toλcan be observed in the reliability curves of ISOⅡandⅢmembership functions.The reliability of the ISOⅠmembership function is not sensitive toλwhenλ<0.7,whereas it becomes sensitive toλwhenλ>0.7.展开更多
The Caohai Wetland is an important habitat for many rare birds,such as black-necked cranes.This study focused on the species composition and diversity of plants in the seven main habitats of black-necked cranes in the...The Caohai Wetland is an important habitat for many rare birds,such as black-necked cranes.This study focused on the species composition and diversity of plants in the seven main habitats of black-necked cranes in the Caohai Wetland,and on the distribution characteristics of black-necked cranes in these habitats in the winter season from November in 2022 to March in 2023.A total of 138 species belonging to 111 genera,40 families,23 orders and 4 classes and 2 phyla were recorded during field investigations involving 31 investigated plots,which comprised 112 quadrats.Among the different investigated plots in the seven habitats of black-necked cranes,the Shannon-Wiener index values ranged from 0.1125 to 2.4800.Notably,plant species diversity decreased in almost all habitats from the terrestrial zone to the water-land transitional zone and from the water-land transitional zone to the shallow water zone.The water level,habitat area,microcirculation heterogeneity and grazing activities are critical factors related to plant species diversity.In this winter,about 2,469 black-necked cranes overwintered in the seven main habitats.Black-necked cranes inhabiting in Huyelin(HYL)and Wenjiatun(WJT)are of absolute advantage in terms of population among the seven major habitats.To better protect the habitat of black necked cranes,we need to control the spread of tall plants,scientifically regulate the plant community structure of the habitat in combining with black necked crane feeding habits,and to regulate the water level of Caohai Lake reasonably to ensure sufficient water-land transitional zone and shallow water zone for black-necked cranes to inhabit.展开更多
The gantry crane system is a crucial equipment for loading and unloading containers at the shore site.The existing trend of crane technology is in the transition from in-site operators to remote operators outside the ...The gantry crane system is a crucial equipment for loading and unloading containers at the shore site.The existing trend of crane technology is in the transition from in-site operators to remote operators outside the cargo handling site,which will comply with all safety regulations,including conditional crane monitoring.However,remote control introduces certain drawbacks in machine maintenance,as no on-site operators can provide real-time feedback on abnormalities.Therefore,this study proposes a failure detection system that uses vibratory sensors installed on machines to monitor and provide early warnings for various failures.For faulty event identification,the Fast Fourier Transform is carried out for the raw vibratory signals,and several frequency bands are classified by using t-SNE to evaluate the significance among clusters.The adjustment of hyperparameters of the t-SNE will alter the quality of the classification of different events,and this process is conventionally operated in accordance with users’experience.In this study,we propose a novel rating approach to automatically tune the hyperparameters of t-SNE to evaluate the separation and cluster compactness of the t-SNE results.Then,the results of clusters served as input features for training the faulty event detection model,and the detection model shows more than 95%accuracy in identifying different abnormal conditions of the main hosting motor.展开更多
Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cyc...Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.展开更多
Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural we...Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.展开更多
Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of...Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of remote sensing and environmental data, this study used the MaxEnt model to assess wintering habitat suitability in Poyang Lake (PYL) and the Yellow River Delta (YRD). Landscape pattern and ecological network (EN) analyses were integrated to examine habitat changes and their impact on Siberian Crane distribution. In PYL, land use/land cover (LULC) change was driven primarily by water level fluctuations, leading to transitions among natural habitat types. In contrast, LULC change in YRD was dominated by anthropogenic activities, with widespread conversion of natural habitats into artificial habitats. In both regions, Siberian Cranes favored wetlands that are food-rich, flat, and minimally disturbed. In PYL, ecological sources were mainly found in sub-lakes of nature reserves and nearby moist areas, averaging 87.42 km^(2). In the YRD, sources were distributed across tidal flats, paddy land, and grasslands, with a larger mean area of 198.37 km^(2). Mann–Kendall tests showed significant trends in PYL, including increased patch density and decreased EN cumulative resilience. The maximum habitat suitability in the YRD significantly declined. Comparative analysis revealed that PYL had significantly higher habitat suitability and EN cumulative resilience, whereas the YRD had larger but more fragmented habitats. By introducing key stepping-stone nodes to optimize the ENs, the connectivity and resilience of PYL's EN were notably enhanced. Although improvements in the YRD were less marked, the optimization scheme still improved the security of the crane migration network. Based on the findings, it is recommended to implement refined water level management in PYL to maintain the stability of sub-lakes and adjacent wetlands, and to strengthen the protection of natural wetlands in the YRD by limiting the expansion of artificial land use, in order to mitigate habitat fragmentation.展开更多
Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population siz...Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population size and distribution of the Black-necked Crane(Grus nigricollis)in the Yarlung Zangbo River Basin(YZRB)from 10 to 29 January 2022,and predicted the current potentially suitable habitat distribution and its effective factors using the Max Ent model.A total of 9337 wintering Black-necked Cranes were recorded in the YZRB in 2022,76.58%of which were primarily found in Lhunzub,Samzhubze,Namling,and Lhaze.Compared to 2018,the crane population has exhibited a notable decline in Samzhubze and Taktse,likely due to farmland plowing,winter irrigation,changes in agricultural practices,road construction and hydraulic projects.The crane population within various counties exhibited a significant positive correlation with the suitable habitat area(r=0.70,P=0.002,n=17).We also found that the currently suitable habitat area covered 17,204 km~2,of which only 3244 km~2(18.86%)was effectively protected at the national level,which was predominantly distributed in farmland and rangeland habitats characterized by gentle slopes,altitudes not exceeding 4500 m,and proximity to human settlements along rivers,where suitable isothermal values(51)and less seasonal precipitation(20 mm)prevail.Our study will be helpful for formulating reasonable conservation strategies to protect the core population of this threatened highland flagship species.展开更多
The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource uti...The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource utilization, including partitioning, in degraded wetlands has become a hot issue in ecological studies of wintering waterbirds. In order to have an insight into the habitat utilization and resource partitioning between a Hooded Crane(Grus monacha) population and the guild of three goose species, i.e., Anser fabalis, A. albifrons and A. erythropus wintering in lake wetlands, we carried out a study at Shengjin Lake National Nature Reserve from November 2011 to April 2012. We surveyed the Hooded Cranes and goose guild foraging in various habitats during the wintering periods with a combined method of fixed route searching and fixed site observations. Resource partitioning was studied by means of calculating habitat utilization rates and the width and overlap of spatial niches. The results showed that the habitat utilization rate and the width of spatial niches of the Hooded Crane population and goose guild shifted with the season. The habitat utilization rates of the cranes in grasslands were high at all three wintering stages. The habitat utilization rates were 0.454, 0.435 and 0.959 respectively for the Hooded Cranes and 0.627, 0.491 and 0.616 for the goose guild. This suggests that the overlap in grasslands was higher between cranes and goose guild. Most habitats were accessible at the middle stage, so the width of the spatial niche of the cranes(1.099) and goose guild(1.133) both reached their peak at this stage. The greatest niche overlap was 0.914 for these two groups at the late stage, followed by 0.906 at the middle stage and the smallest was 0.854 at the early stage. Ecological response to the changes in habitats of wintering waterbirds was clearly shown in the dynamic variations of the niche of both the Hooded Cranes and the three goose species. Coexistence among waterbirds was achieved by regulation of niche width to reduce niche overlap and relieve interspecific resource partitioning.展开更多
There is a lack of information of whether the behavior pattern and physical condition of the Hooded Crane (Grus monacha) have been limited by conditions encountered at stopover sites in Changgou village,which is adjac...There is a lack of information of whether the behavior pattern and physical condition of the Hooded Crane (Grus monacha) have been limited by conditions encountered at stopover sites in Changgou village,which is adjacent to Zhalong Nature Reserve in northeastern China,one of the most important stopover sites of this crane.The objective of our research was to investigatethe impact of human-caused disturbances on the Hooded Cranes.We investigated three behavior activities of the Hooded Cranes,i.e.,flying time,flushing distance and the duration of vigilance.The results indicate that the auditory stimuli caused by local people provoked the most pronounced disturbances to the Hooded Crane.Human-caused disturbances not only frequently interrupt the feeding process of the cranes,but also lead to an increase of 200％ in the duration of their vigilance and a significant increase in flying time from 0.4 to 0.7 h (p ＜ 0.05).In addition,high-intensity noise can cause larger flushing distances; foraging cranes will flush away by about 600 m when disturbed by the honking of vehicles.Whistles or shouts by local farmers in the field generated the largest sound intensity,about 120 dB,which caused a flushing distance of over 700 m.In order to reduce the negative effect of human-caused disturbances on these cranes,it is imperative to define a buffer zone around sensitive areas during the fall stopover period.To solve the conflict between the interest of farmers and the demand for crops on the part of the cranes requires financial compensation to the farmers for the crops consumed by the Hooded Crane in order to enhance the conservation of this vulnerable bird species.展开更多
In order to study the fatigue behavior of the damaged reinforced concrete （RC） beams strengthened by carbon fiber reinforced polymer （CFRP） laminate, three T-shaped beams strengthened by CFRP and one contrasting b...In order to study the fatigue behavior of the damaged reinforced concrete （RC） beams strengthened by carbon fiber reinforced polymer （CFRP） laminate, three T-shaped beams strengthened by CFRP and one contrasting beam are tested under fatigue loading, with the parameters of different modes of strengthening and different fatigue load levels considered. The main results obtained from the tests are： the width of the crack decreases 50. 2% to 66%, and the development of the crack is limited; the stress of steel decreases 24. 1% to 28. 2%, and the stiffness increases 14.9% to 16. 1% after being strengthened. Based on the technical specification for strengthening concrete structures with CFRP and the conclusions from the tests, a calculating scheme of the flexure stiffness is given, which can be used for reference in engineering design. Finally, some suggestions are given for design in fatigue strengthening.展开更多
In order to measure the impact of changes in the marsh on breeding Red-crowned Cranes (Grus japonensis) and White-naped Cranes (G.vipio) in the Sanjiang Plain,we conducted a complete crane súrvey in each of the s...In order to measure the impact of changes in the marsh on breeding Red-crowned Cranes (Grus japonensis) and White-naped Cranes (G.vipio) in the Sanjiang Plain,we conducted a complete crane súrvey in each of the summers of 2007 and 2008,and obtained information on the changes in its marsh through interpretation of satellite images in 1986,1995,2000 and 2005.A comparison between the 1984 and 2008 census shows that:1) the number of Red-crowned Cranes remained stable at about 300 birds,while the number of White-naped Cranes increased markedly; 2) the estimates of nests of Red-crowned cranes are close to the numbers of 1984,while approximately 90％ of the nests of these two crane species were distributed over five national nature reserves (NNRs); 3) the two crane species became more concentrated in three regions,i.e.,the Fuyuan Delta,the middle reaches of the Naoli and Qixing rivers,and the Xingkai Lake wetlands,rather as formerly in six regions.The area of the marsh decreased by 45％ within the 20-year period from 1986 to 2005.The major loss of the marsh area was in the form of a conversion to paddy fields and dry land,which can be primarily attributed to direct human activity under various economic and policy drivers.The disappearance of cranes in the Dulu and Abuqin rivers was induced by large-scale agricultural development.The fragmentation into and isolation of small areas of the marsh became increasingly more serious,which resulted in unsuitable condtions for crane breeding in small patches of the marsh.The number of cranes declined from 1984-1995 but had recovered remarkably by 2008,which may be due to theestablishment of a system of nature reserves,in place since 2000.The land ownership of the reserve plays a key role in maintaining the integrity of the wetland ecosystem,especially in Sanjiang,Honghe,Naolihe and Qixinghe NNRs,which together accommodated approximately 80％ of the population of cranes.However,we did not discover any nests at all in the provincial and municipal reserves,which may be attributed to high human disturbances in these areas.In the end,we propose some recommendations on reserve management.展开更多
In order to assess the effect of the observer distance on the behavior of Red-crowned Cranes (Grus japonensis),we studied their time budgets with a gradient of observer distances in Yancheng,China from December 2008 t...In order to assess the effect of the observer distance on the behavior of Red-crowned Cranes (Grus japonensis),we studied their time budgets with a gradient of observer distances in Yancheng,China from December 2008 to March 2009.Observer distance was classified into four levels,i.e.,＜ 200 m,200-300 m,300-400 m and ＞ 400 m.The results indicated that cranes increased their vigilance when the observer was less than 300 m away.A safe distance for the observer was often as far as or more than 300 m.Cranes increased scan frequency when observers were within 200 m,whereas they prolonged the duration of their scan when observers were between 200 m and 300 m away,indicating two distinct vigilant strategies,given the observer distance.We suggest an observer distance of at least 300 m,in order to minimize the observer effect.展开更多
This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equation...This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equations of the system are recursively derived by a Newton Euler method. The dynamic behavior of the load of slewing crane in rotating motion is simulated on a computer. The method of robotic dynamics to derive the dynamic equations of the swing of load is accurate and convenient and it has good regularity. The result of the study provides a base in theory on design of crane and an accurate mathematical model for controlling the swing of load.展开更多
The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,popula...The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,population dynamics,flock size and behavior was conducted in Altun Mountain National Natural Reserve from September to November 2011.We investigated the size and distribution of its population in this area with a sample spot survey and by direct counting.We found Black-necked Cranes on the wetlands of Wuzunxiaoer,Yusup Aleksei,Yaziquan,Qimantag,Tula Ranch and elsewhere,where we recorded 126 individual birds of the species in Yixiekepati (37° 15′-37°23′N,90°11′-90°20′E,elevation 3903 m),the largest population we have observed in this area.In the reserve,the population consists of about 180-200 birds.Combined with previous records,we conclude that more than 260 Black-necked Cranes live in Xinjiang.Cranes gathered conspicuously in the middle of October where the highest number of birds appeared on 29 October.All of the cranes had migrated out of this area by 6 November.Time budgets and diurnal behavior rhythms of Blacknecked Cranes were observed in the Yixiekepati wetland at daylight (from 06:00 to 18:00).Foraging was the most prevalent type of behavior during the autumn period,accounting for 58.9％ of the diurnal time budget,followed by preening (13.2％),vigilance (9.5％),walking (8.2％),flying (3.5％),resting (3.4％),chirping (2.7％) and other types of behavior (0.6％).展开更多
Stephen Crane is one of the greatest figures in the history of American literature and his novella The Open Boat is widely known by people all over the world as a representative work of Naturalism. This paper aims at ...Stephen Crane is one of the greatest figures in the history of American literature and his novella The Open Boat is widely known by people all over the world as a representative work of Naturalism. This paper aims at exploring Naturalism in Stephen Crane's The Open Boat,which will guide the readers to understand American Naturalism accurately and thoroughly. It firstly introduces the author and his novel The Open Boat. Secondly,it progressively dissects Naturalism. It not only analyses the general characteristics of Naturalism with details in The Open Boat,but also interprets the distinguishing features of American Naturalism so that readers can better understand the features of American Naturalism. Through textual perusal,it further studies the unique characteristics of Stephen Crane's Naturalism and lays particular emphasis on Crane's special concern on the awakening of humanity. It is hoped that this thesis can help readers get an in-depth comprehension of Naturalism and gain some inspiration from TheOpenBoat.展开更多
基金The National Natural Science Foundation of China(No.52108274,52208481,52338011)State Scholarship Fund of China Scholarship Council(No.202306090285).
文摘The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency.Therefore,the wind-resistant fuzzy comfortability of a super-high tower crane in the Ma’anshan Yangtze River(MYR)Bridge site is analyzed in this paper.First,the membership function model that represents fuzzy comfortability is introduced in the probability density evolution method(PDEM).Second,based on Fechner’s law,the membership function curves are constructed according to three acceleration thresholds in ISO 2631.Then,the fuzzy comfortability for the super-high tower crane under stochastic wind loads is assessed on the basis of different cut-set levelsλ.Results show that the comfortability is over 0.9 under the required maximum operating wind velocity.The low sensitivity toλcan be observed in the reliability curves of ISOⅡandⅢmembership functions.The reliability of the ISOⅠmembership function is not sensitive toλwhenλ<0.7,whereas it becomes sensitive toλwhenλ>0.7.
基金supported by the Guizhou Provincial Science and Technology Projects(No.QKHZC[2023]YB215,QKHPT[2025]015).
文摘The Caohai Wetland is an important habitat for many rare birds,such as black-necked cranes.This study focused on the species composition and diversity of plants in the seven main habitats of black-necked cranes in the Caohai Wetland,and on the distribution characteristics of black-necked cranes in these habitats in the winter season from November in 2022 to March in 2023.A total of 138 species belonging to 111 genera,40 families,23 orders and 4 classes and 2 phyla were recorded during field investigations involving 31 investigated plots,which comprised 112 quadrats.Among the different investigated plots in the seven habitats of black-necked cranes,the Shannon-Wiener index values ranged from 0.1125 to 2.4800.Notably,plant species diversity decreased in almost all habitats from the terrestrial zone to the water-land transitional zone and from the water-land transitional zone to the shallow water zone.The water level,habitat area,microcirculation heterogeneity and grazing activities are critical factors related to plant species diversity.In this winter,about 2,469 black-necked cranes overwintered in the seven main habitats.Black-necked cranes inhabiting in Huyelin(HYL)and Wenjiatun(WJT)are of absolute advantage in terms of population among the seven major habitats.To better protect the habitat of black necked cranes,we need to control the spread of tall plants,scientifically regulate the plant community structure of the habitat in combining with black necked crane feeding habits,and to regulate the water level of Caohai Lake reasonably to ensure sufficient water-land transitional zone and shallow water zone for black-necked cranes to inhabit.
基金funded by National Science and Technology Council,Taiwan,grant numbers 112-2622-E-992-022 and 112-2221-E-992-086.
文摘The gantry crane system is a crucial equipment for loading and unloading containers at the shore site.The existing trend of crane technology is in the transition from in-site operators to remote operators outside the cargo handling site,which will comply with all safety regulations,including conditional crane monitoring.However,remote control introduces certain drawbacks in machine maintenance,as no on-site operators can provide real-time feedback on abnormalities.Therefore,this study proposes a failure detection system that uses vibratory sensors installed on machines to monitor and provide early warnings for various failures.For faulty event identification,the Fast Fourier Transform is carried out for the raw vibratory signals,and several frequency bands are classified by using t-SNE to evaluate the significance among clusters.The adjustment of hyperparameters of the t-SNE will alter the quality of the classification of different events,and this process is conventionally operated in accordance with users’experience.In this study,we propose a novel rating approach to automatically tune the hyperparameters of t-SNE to evaluate the separation and cluster compactness of the t-SNE results.Then,the results of clusters served as input features for training the faulty event detection model,and the detection model shows more than 95%accuracy in identifying different abnormal conditions of the main hosting motor.
基金funded by the National Natural Science Foundation of China(No.32470553).
文摘Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.
基金supported by the National Natural Science Foundation of China(No.32260275)Fundamental Research Funds of CAF(CAFYBB2024ZA033)。
文摘Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.
基金supported by the National Natural Science Foundation of China(Grant No.32360142).
文摘Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of remote sensing and environmental data, this study used the MaxEnt model to assess wintering habitat suitability in Poyang Lake (PYL) and the Yellow River Delta (YRD). Landscape pattern and ecological network (EN) analyses were integrated to examine habitat changes and their impact on Siberian Crane distribution. In PYL, land use/land cover (LULC) change was driven primarily by water level fluctuations, leading to transitions among natural habitat types. In contrast, LULC change in YRD was dominated by anthropogenic activities, with widespread conversion of natural habitats into artificial habitats. In both regions, Siberian Cranes favored wetlands that are food-rich, flat, and minimally disturbed. In PYL, ecological sources were mainly found in sub-lakes of nature reserves and nearby moist areas, averaging 87.42 km^(2). In the YRD, sources were distributed across tidal flats, paddy land, and grasslands, with a larger mean area of 198.37 km^(2). Mann–Kendall tests showed significant trends in PYL, including increased patch density and decreased EN cumulative resilience. The maximum habitat suitability in the YRD significantly declined. Comparative analysis revealed that PYL had significantly higher habitat suitability and EN cumulative resilience, whereas the YRD had larger but more fragmented habitats. By introducing key stepping-stone nodes to optimize the ENs, the connectivity and resilience of PYL's EN were notably enhanced. Although improvements in the YRD were less marked, the optimization scheme still improved the security of the crane migration network. Based on the findings, it is recommended to implement refined water level management in PYL to maintain the stability of sub-lakes and adjacent wetlands, and to strengthen the protection of natural wetlands in the YRD by limiting the expansion of artificial land use, in order to mitigate habitat fragmentation.
基金supported by the National Natural Science Foundation of China(32070530)the National Key Research and Development Program of China(2019YFA0607103)+1 种基金the Qilian Mountain National Park Qinghai Province Management Bureauthe National Forestry and Grassland Administration of China。
文摘Evaluating the habitat suitability of flagship species and its key influencing factors is vital for understanding potential conservation issues and developing coping strategies.We surveyed the wintering population size and distribution of the Black-necked Crane(Grus nigricollis)in the Yarlung Zangbo River Basin(YZRB)from 10 to 29 January 2022,and predicted the current potentially suitable habitat distribution and its effective factors using the Max Ent model.A total of 9337 wintering Black-necked Cranes were recorded in the YZRB in 2022,76.58%of which were primarily found in Lhunzub,Samzhubze,Namling,and Lhaze.Compared to 2018,the crane population has exhibited a notable decline in Samzhubze and Taktse,likely due to farmland plowing,winter irrigation,changes in agricultural practices,road construction and hydraulic projects.The crane population within various counties exhibited a significant positive correlation with the suitable habitat area(r=0.70,P=0.002,n=17).We also found that the currently suitable habitat area covered 17,204 km~2,of which only 3244 km~2(18.86%)was effectively protected at the national level,which was predominantly distributed in farmland and rangeland habitats characterized by gentle slopes,altitudes not exceeding 4500 m,and proximity to human settlements along rivers,where suitable isothermal values(51)and less seasonal precipitation(20 mm)prevail.Our study will be helpful for formulating reasonable conservation strategies to protect the core population of this threatened highland flagship species.
基金supported by the National Natural Science Foundation of China(Grant No.31172117)the Graduate Student Innovation Research Projects of Anhui University(Grant No.yqh100118)the Anhui Academic and Technical Leader Fund
文摘The loss and degradation of wetlands have adversely affected waterbirds, which depend on wetland habitats. Interspecific competition has an important effect on habitat utilization of wintering waterbirds. Resource utilization, including partitioning, in degraded wetlands has become a hot issue in ecological studies of wintering waterbirds. In order to have an insight into the habitat utilization and resource partitioning between a Hooded Crane(Grus monacha) population and the guild of three goose species, i.e., Anser fabalis, A. albifrons and A. erythropus wintering in lake wetlands, we carried out a study at Shengjin Lake National Nature Reserve from November 2011 to April 2012. We surveyed the Hooded Cranes and goose guild foraging in various habitats during the wintering periods with a combined method of fixed route searching and fixed site observations. Resource partitioning was studied by means of calculating habitat utilization rates and the width and overlap of spatial niches. The results showed that the habitat utilization rate and the width of spatial niches of the Hooded Crane population and goose guild shifted with the season. The habitat utilization rates of the cranes in grasslands were high at all three wintering stages. The habitat utilization rates were 0.454, 0.435 and 0.959 respectively for the Hooded Cranes and 0.627, 0.491 and 0.616 for the goose guild. This suggests that the overlap in grasslands was higher between cranes and goose guild. Most habitats were accessible at the middle stage, so the width of the spatial niche of the cranes(1.099) and goose guild(1.133) both reached their peak at this stage. The greatest niche overlap was 0.914 for these two groups at the late stage, followed by 0.906 at the middle stage and the smallest was 0.854 at the early stage. Ecological response to the changes in habitats of wintering waterbirds was clearly shown in the dynamic variations of the niche of both the Hooded Cranes and the three goose species. Coexistence among waterbirds was achieved by regulation of niche width to reduce niche overlap and relieve interspecific resource partitioning.
文摘There is a lack of information of whether the behavior pattern and physical condition of the Hooded Crane (Grus monacha) have been limited by conditions encountered at stopover sites in Changgou village,which is adjacent to Zhalong Nature Reserve in northeastern China,one of the most important stopover sites of this crane.The objective of our research was to investigatethe impact of human-caused disturbances on the Hooded Cranes.We investigated three behavior activities of the Hooded Cranes,i.e.,flying time,flushing distance and the duration of vigilance.The results indicate that the auditory stimuli caused by local people provoked the most pronounced disturbances to the Hooded Crane.Human-caused disturbances not only frequently interrupt the feeding process of the cranes,but also lead to an increase of 200％ in the duration of their vigilance and a significant increase in flying time from 0.4 to 0.7 h (p ＜ 0.05).In addition,high-intensity noise can cause larger flushing distances; foraging cranes will flush away by about 600 m when disturbed by the honking of vehicles.Whistles or shouts by local farmers in the field generated the largest sound intensity,about 120 dB,which caused a flushing distance of over 700 m.In order to reduce the negative effect of human-caused disturbances on these cranes,it is imperative to define a buffer zone around sensitive areas during the fall stopover period.To solve the conflict between the interest of farmers and the demand for crops on the part of the cranes requires financial compensation to the farmers for the crops consumed by the Hooded Crane in order to enhance the conservation of this vulnerable bird species.
基金The Natural Science Foundation of Jiangsu Province(NoBK2004064)the Postdoctoral Foundation of Jiangsu Province(No0701008B)
文摘In order to study the fatigue behavior of the damaged reinforced concrete （RC） beams strengthened by carbon fiber reinforced polymer （CFRP） laminate, three T-shaped beams strengthened by CFRP and one contrasting beam are tested under fatigue loading, with the parameters of different modes of strengthening and different fatigue load levels considered. The main results obtained from the tests are： the width of the crack decreases 50. 2% to 66%, and the development of the crack is limited; the stress of steel decreases 24. 1% to 28. 2%, and the stiffness increases 14.9% to 16. 1% after being strengthened. Based on the technical specification for strengthening concrete structures with CFRP and the conclusions from the tests, a calculating scheme of the flexure stiffness is given, which can be used for reference in engineering design. Finally, some suggestions are given for design in fatigue strengthening.
基金supported by the Conservation Fund of the State Forestry Administration of China and the Siberian Crane Wetland GEF/UNEP Project(GF/2712-03-4627)
文摘In order to measure the impact of changes in the marsh on breeding Red-crowned Cranes (Grus japonensis) and White-naped Cranes (G.vipio) in the Sanjiang Plain,we conducted a complete crane súrvey in each of the summers of 2007 and 2008,and obtained information on the changes in its marsh through interpretation of satellite images in 1986,1995,2000 and 2005.A comparison between the 1984 and 2008 census shows that:1) the number of Red-crowned Cranes remained stable at about 300 birds,while the number of White-naped Cranes increased markedly; 2) the estimates of nests of Red-crowned cranes are close to the numbers of 1984,while approximately 90％ of the nests of these two crane species were distributed over five national nature reserves (NNRs); 3) the two crane species became more concentrated in three regions,i.e.,the Fuyuan Delta,the middle reaches of the Naoli and Qixing rivers,and the Xingkai Lake wetlands,rather as formerly in six regions.The area of the marsh decreased by 45％ within the 20-year period from 1986 to 2005.The major loss of the marsh area was in the form of a conversion to paddy fields and dry land,which can be primarily attributed to direct human activity under various economic and policy drivers.The disappearance of cranes in the Dulu and Abuqin rivers was induced by large-scale agricultural development.The fragmentation into and isolation of small areas of the marsh became increasingly more serious,which resulted in unsuitable condtions for crane breeding in small patches of the marsh.The number of cranes declined from 1984-1995 but had recovered remarkably by 2008,which may be due to theestablishment of a system of nature reserves,in place since 2000.The land ownership of the reserve plays a key role in maintaining the integrity of the wetland ecosystem,especially in Sanjiang,Honghe,Naolihe and Qixinghe NNRs,which together accommodated approximately 80％ of the population of cranes.However,we did not discover any nests at all in the provincial and municipal reserves,which may be attributed to high human disturbances in these areas.In the end,we propose some recommendations on reserve management.
基金support from the Chinese Key Technology R&D Program of the Eleventh Five-year Plan(No.2008BAC39B03)the Nanjing University Funds for Starting Research
文摘In order to assess the effect of the observer distance on the behavior of Red-crowned Cranes (Grus japonensis),we studied their time budgets with a gradient of observer distances in Yancheng,China from December 2008 to March 2009.Observer distance was classified into four levels,i.e.,＜ 200 m,200-300 m,300-400 m and ＞ 400 m.The results indicated that cranes increased their vigilance when the observer was less than 300 m away.A safe distance for the observer was often as far as or more than 300 m.Cranes increased scan frequency when observers were within 200 m,whereas they prolonged the duration of their scan when observers were between 200 m and 300 m away,indicating two distinct vigilant strategies,given the observer distance.We suggest an observer distance of at least 300 m,in order to minimize the observer effect.
文摘This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equations of the system are recursively derived by a Newton Euler method. The dynamic behavior of the load of slewing crane in rotating motion is simulated on a computer. The method of robotic dynamics to derive the dynamic equations of the swing of load is accurate and convenient and it has good regularity. The result of the study provides a base in theory on design of crane and an accurate mathematical model for controlling the swing of load.
基金supported by the National Natural Science Foundation of China(No.31272291,30970340)the Hong Kong Bird Watching Society China Conservation Fund and the Management Bureau of Altun Mountain Natural Reserve
文摘The Black-necked Crane (Grus nigricollis) is an endemic species of the Qinghai-Tibetan Plateau,with its population in Xinjiang largely found in the Kunlun and Altun mountain regions.A survey of the distribution,population dynamics,flock size and behavior was conducted in Altun Mountain National Natural Reserve from September to November 2011.We investigated the size and distribution of its population in this area with a sample spot survey and by direct counting.We found Black-necked Cranes on the wetlands of Wuzunxiaoer,Yusup Aleksei,Yaziquan,Qimantag,Tula Ranch and elsewhere,where we recorded 126 individual birds of the species in Yixiekepati (37° 15′-37°23′N,90°11′-90°20′E,elevation 3903 m),the largest population we have observed in this area.In the reserve,the population consists of about 180-200 birds.Combined with previous records,we conclude that more than 260 Black-necked Cranes live in Xinjiang.Cranes gathered conspicuously in the middle of October where the highest number of birds appeared on 29 October.All of the cranes had migrated out of this area by 6 November.Time budgets and diurnal behavior rhythms of Blacknecked Cranes were observed in the Yixiekepati wetland at daylight (from 06:00 to 18:00).Foraging was the most prevalent type of behavior during the autumn period,accounting for 58.9％ of the diurnal time budget,followed by preening (13.2％),vigilance (9.5％),walking (8.2％),flying (3.5％),resting (3.4％),chirping (2.7％) and other types of behavior (0.6％).
文摘Stephen Crane is one of the greatest figures in the history of American literature and his novella The Open Boat is widely known by people all over the world as a representative work of Naturalism. This paper aims at exploring Naturalism in Stephen Crane's The Open Boat,which will guide the readers to understand American Naturalism accurately and thoroughly. It firstly introduces the author and his novel The Open Boat. Secondly,it progressively dissects Naturalism. It not only analyses the general characteristics of Naturalism with details in The Open Boat,but also interprets the distinguishing features of American Naturalism so that readers can better understand the features of American Naturalism. Through textual perusal,it further studies the unique characteristics of Stephen Crane's Naturalism and lays particular emphasis on Crane's special concern on the awakening of humanity. It is hoped that this thesis can help readers get an in-depth comprehension of Naturalism and gain some inspiration from TheOpenBoat.
