The sea surface escort formation faces various threats in reality. For example, suicide boats may carry explosives or other dangerous items, aiming to cause maximum damage by colliding or detonating escort targets. Si...The sea surface escort formation faces various threats in reality. For example, suicide boats may carry explosives or other dangerous items, aiming to cause maximum damage by colliding or detonating escort targets. Since suicide boats have a certain degree of concealment, it is necessary to establish a threat assessment algorithm to timely identify and respond to such fast and concealed threats. This paper establishes a threat assessment model that considers the instantaneous and historical states of the target. The instantaneous state of the target takes into account six evaluation indicators, including target category, target distance, target heading, target speed, collision risk, and ship automatic identification system(AIS) recognition status;in terms of historical state information mining, a target typical intention recognition method based on graph neural network is proposed to achieve end-to-end target typical intention recognition. Furthermore, this paper introduces a multi-attribute decision analysis method to weight the evaluation indicators, improves the relative closeness calculation method between different evaluation schemes and positive and negative ideal schemes, and determines the target threat ranking based on relative closeness. Based on Unity3D, a set of unmanned boat confrontation simulation system is designed and developed, and typical intention recognition data sets and threat assessment scenario simulation data are generated through real-life confrontation. Comparative analysis shows that the threat assessment model in this paper can accurately and timely detect raid target threats and give scientific and reasonable target threat ranking results.展开更多
Unregulated commercial-scale exploitation of trees is an indication of the extent of threat to various tree species. The study examined the threat status of commercially exploited trees in the forest estates of South ...Unregulated commercial-scale exploitation of trees is an indication of the extent of threat to various tree species. The study examined the threat status of commercially exploited trees in the forest estates of South eastern Nigeria. Specifically, it identified tree species under threat, and categorized them into threat classes, as well as determined the rate at which exploited trees were slipping into extinction. The study utilized the IUCN’s threat categorization criteria, in determining the threat status of commercially exploited trees. This study combined both secondary and primary data sources generated through Forest Inventory records, Tree Felled Analysis records and Participatory Survey. Data such as population size and density of species, level of exploitation and threat sensitive social and ecological parameters were obtained and applied against the IUCN criteria. Twenty-eight (28) trees species representing Thirty-two percent (32%) of eighty-six (86) commercially exploited trees were identified as threatened, ranging from the Vulnerable to the Critically Endangered categories. The theory of small and declining population paradigms were found to be of relevance in explaining the processes. Nine tree species such as Triplochiton spp., Baillonella toxisperma, Pogaoleosa, Anopyxis spp. among others were considered to require urgent conservation attention. Recommendations are proposed to halt the process of decline in the biodiversity of exploited trees.展开更多
Recent studies have revealed concerning declines in bird populations in Europe and other parts of the world.In understudied but biodiverse regions,especially those that are located along key migratory flyways,there is...Recent studies have revealed concerning declines in bird populations in Europe and other parts of the world.In understudied but biodiverse regions,especially those that are located along key migratory flyways,there is an unmet need to evaluate the status of resident and migratory birdlife for avian conservation ecology.This is especially urgent at a time when recent regional studies have highlighted the scale of the decline of the European and Palearctic avifauna.Rapidly growing community science datasets may help bridge the gaps in our understanding of long-term regional avifaunal trends.In this study,we used eBird data submitted by observers in Türkiye to undertake the first long-term assessment of the state of the country’s birds from 2001 to 2022.We evaluated population trends based on presence-absence data of species to determine if any birds have significantly increased or decreased in the country so far this century.We provide a list of trends for 418 bird species that had large enough sample sizes of eBird observations from Türkiye,and highlight which species have significantly declined or increased.We found that 63 species have significantly declined in detection while 120 have significantly increased during the study period.Our findings provide a baseline for the future monitoring of Türkiye’s birds and help contextualize population changes of birds in Türkiye against those occurring at the continental(Palearctic)scale.Additionally,we include movement classifications for all of the bird species in this study.We also provide a framework to effectively use eBird data to assess long-term avifaunal changes at the country-level in other understudied regions.Finally,we highlight ways in which eBirders in Türkiye and elsewhere can strengthen the quality and value of community ornithology data for population assessments and avian conservation ecology.展开更多
基金funded by by the National Natural Science Foundation of China under Grant 52101377。
文摘The sea surface escort formation faces various threats in reality. For example, suicide boats may carry explosives or other dangerous items, aiming to cause maximum damage by colliding or detonating escort targets. Since suicide boats have a certain degree of concealment, it is necessary to establish a threat assessment algorithm to timely identify and respond to such fast and concealed threats. This paper establishes a threat assessment model that considers the instantaneous and historical states of the target. The instantaneous state of the target takes into account six evaluation indicators, including target category, target distance, target heading, target speed, collision risk, and ship automatic identification system(AIS) recognition status;in terms of historical state information mining, a target typical intention recognition method based on graph neural network is proposed to achieve end-to-end target typical intention recognition. Furthermore, this paper introduces a multi-attribute decision analysis method to weight the evaluation indicators, improves the relative closeness calculation method between different evaluation schemes and positive and negative ideal schemes, and determines the target threat ranking based on relative closeness. Based on Unity3D, a set of unmanned boat confrontation simulation system is designed and developed, and typical intention recognition data sets and threat assessment scenario simulation data are generated through real-life confrontation. Comparative analysis shows that the threat assessment model in this paper can accurately and timely detect raid target threats and give scientific and reasonable target threat ranking results.
文摘Unregulated commercial-scale exploitation of trees is an indication of the extent of threat to various tree species. The study examined the threat status of commercially exploited trees in the forest estates of South eastern Nigeria. Specifically, it identified tree species under threat, and categorized them into threat classes, as well as determined the rate at which exploited trees were slipping into extinction. The study utilized the IUCN’s threat categorization criteria, in determining the threat status of commercially exploited trees. This study combined both secondary and primary data sources generated through Forest Inventory records, Tree Felled Analysis records and Participatory Survey. Data such as population size and density of species, level of exploitation and threat sensitive social and ecological parameters were obtained and applied against the IUCN criteria. Twenty-eight (28) trees species representing Thirty-two percent (32%) of eighty-six (86) commercially exploited trees were identified as threatened, ranging from the Vulnerable to the Critically Endangered categories. The theory of small and declining population paradigms were found to be of relevance in explaining the processes. Nine tree species such as Triplochiton spp., Baillonella toxisperma, Pogaoleosa, Anopyxis spp. among others were considered to require urgent conservation attention. Recommendations are proposed to halt the process of decline in the biodiversity of exploited trees.
文摘Recent studies have revealed concerning declines in bird populations in Europe and other parts of the world.In understudied but biodiverse regions,especially those that are located along key migratory flyways,there is an unmet need to evaluate the status of resident and migratory birdlife for avian conservation ecology.This is especially urgent at a time when recent regional studies have highlighted the scale of the decline of the European and Palearctic avifauna.Rapidly growing community science datasets may help bridge the gaps in our understanding of long-term regional avifaunal trends.In this study,we used eBird data submitted by observers in Türkiye to undertake the first long-term assessment of the state of the country’s birds from 2001 to 2022.We evaluated population trends based on presence-absence data of species to determine if any birds have significantly increased or decreased in the country so far this century.We provide a list of trends for 418 bird species that had large enough sample sizes of eBird observations from Türkiye,and highlight which species have significantly declined or increased.We found that 63 species have significantly declined in detection while 120 have significantly increased during the study period.Our findings provide a baseline for the future monitoring of Türkiye’s birds and help contextualize population changes of birds in Türkiye against those occurring at the continental(Palearctic)scale.Additionally,we include movement classifications for all of the bird species in this study.We also provide a framework to effectively use eBird data to assess long-term avifaunal changes at the country-level in other understudied regions.Finally,we highlight ways in which eBirders in Türkiye and elsewhere can strengthen the quality and value of community ornithology data for population assessments and avian conservation ecology.
