Traditional expert-designed branching rules in branch-and-bound(B&B) are static, often failing to adapt to diverse and evolving problem instances. Crafting these rules is labor-intensive, and may not scale well wi...Traditional expert-designed branching rules in branch-and-bound(B&B) are static, often failing to adapt to diverse and evolving problem instances. Crafting these rules is labor-intensive, and may not scale well with complex problems.Given the frequent need to solve varied combinatorial optimization problems, leveraging statistical learning to auto-tune B&B algorithms for specific problem classes becomes attractive. This paper proposes a graph pointer network model to learn the branch rules. Graph features, global features and historical features are designated to represent the solver state. The graph neural network processes graph features, while the pointer mechanism assimilates the global and historical features to finally determine the variable on which to branch. The model is trained to imitate the expert strong branching rule by a tailored top-k Kullback-Leibler divergence loss function. Experiments on a series of benchmark problems demonstrate that the proposed approach significantly outperforms the widely used expert-designed branching rules. It also outperforms state-of-the-art machine-learning-based branch-and-bound methods in terms of solving speed and search tree size on all the test instances. In addition, the model can generalize to unseen instances and scale to larger instances.展开更多
The development types of traditional village B&B can be divided into spontaneous style,scenic area driven style and new rural construction led style.The development of B&B in Jinlin Village has certain livable...The development types of traditional village B&B can be divided into spontaneous style,scenic area driven style and new rural construction led style.The development of B&B in Jinlin Village has certain livable environment and resource conditions,good location,profound cultural heritage and government support.It has experienced three stages of construction,namely scenic spot development,civilized village and new countryside.The development type of B&B in Jinlin Village belongs to the dual type of scenic spot driving and new countryside construction.However,over construction has negative impact on the development of B&B.Four planning strategies are put forward,including protecting and activating the traditional houses,increasing the green space to isolate and buffer the impact of new houses on traditional dwellings,opening up new lakeside residential area,and fully protecting and utilizing peripheral farmlands.展开更多
Based on the theory of consumer behavior,with reference to theories of the tourism,according to EBM model in consumer behavior model,it analyzed the agritainment consumption behavior through building a three-stage mod...Based on the theory of consumer behavior,with reference to theories of the tourism,according to EBM model in consumer behavior model,it analyzed the agritainment consumption behavior through building a three-stage model for the agritainment consumption behavior,namely decision stage before travel,travel stage,and evaluation stage after consumption. Taking the urban residents of Huangpi District of Wuhan City as the research objects,using SPSS software,it designed the questionnaire and conducted the survey of agritainment tourists,and analyzed basic characteristics of tourists and their consumption behavior characteristics. In conclusion,the age of tourists has a significant influence on their choice of destination,information channel,and entertainment activities. It is recommended that operators of agritainment can set up entertainment activities according to different age of tourists and transmit information to the right tourists in the right place.展开更多
Based on the development prospect of the industry of keeping in good health and caring for the senior and practical exploration on the Lishui Citys construction of "Health Blessed Land" in Yangtze River Delt...Based on the development prospect of the industry of keeping in good health and caring for the senior and practical exploration on the Lishui Citys construction of "Health Blessed Land" in Yangtze River Delta, the position, function and facing problems of agritainment in the system of industrial economy of keeping in good health and caring for the senior in Lishui City. From the view of the industry integration, this paper puts forward the new strategies of developing agritainment in terms of design concepts at the top level, guarantee conditions in the government, layout strategies stressing on resources, target assessment focusing on nourishing of life, the basic promoting connotation.展开更多
加拿大B&B采矿公司拟在美国加利福尼亚州南部的Castler山以堆浸法开采一新的露天金矿区,该矿区位于圣贝纳迪诺县Castler山的东Mojave National Scenic地区。该矿区包括5个金矿床,有4个露天金矿可供开采,因为矿区南端的Lesley Ann和J...加拿大B&B采矿公司拟在美国加利福尼亚州南部的Castler山以堆浸法开采一新的露天金矿区,该矿区位于圣贝纳迪诺县Castler山的东Mojave National Scenic地区。该矿区包括5个金矿床,有4个露天金矿可供开采,因为矿区南端的Lesley Ann和Jumbo South矿床可合并为一个矿。据公司代理人、加州矿业和开发顾问Marion Ely II透露,计划在5个金矿开采2600万t矿石。展开更多
There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial carrier.Accurately identifying the differences in spatial characteri...There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial carrier.Accurately identifying the differences in spatial characteristics and influencing factors of each type,is essential for creating urban and rural B&B agglomeration areas.This study used density-based spatial clustering of applications with noise(DBSCAN)and the multi-scale geographically weighted regression(MGWR)model to explore similarities and differences in the spatial distribution patterns and influencing factors for urban and rural B&Bs on the Jiaodong Peninsula of China from 2010 to 2022.The results showed that:1)both urban and rural B&Bs in Jiaodong Peninsula went through three stages:a slow start from 2010 to 2015,rapid development from 2015 to 2019,and hindered development from 2019 to 2022.However,urban B&Bs demonstrated a higher development speed and agglomeration intensity,leading to an increasingly evident trend of uneven development between the two sectors.2)The clustering scale of both urban and rural B&Bs continued to expand in terms of quantity and volume.Urban B&B clusters characterized by a limited number,but a higher likelihood of transitioning from low-level to high-level clusters.While the number of rural B&B clusters steadily increased over time,their clustering scale was comparatively lower than that of urban B&Bs,and they lacked the presence of high-level clustering.3)In terms of development direction,urban B&B clusters exhibited a relatively stable pattern and evolved into high-level clustering centers within the main urban areas.Conversely,rural B&Bs exhibited a more pronounced spatial diffusion effect,with clusters showing a trend of multi-center development along the coastline.4)Transport emerged as a common influencing factor for both urban and rural B&Bs,with the density of road network having the strongest explanatory power for their spatial distribution.In terms of differences,population agglomeration had a positive impact on the distribution of urban B&Bs and a negative effect on the distribution of rural B&Bs.Rural B&Bs clustering was more influenced by tourism resources compared with urban B&Bs,but increasing tourist stay duration remains an urgent issue to be addressed.The findings of this study could provide a more precise basis for government planning and management of urban and rural B&B agglomeration areas.展开更多
Nowadays the farm-based tour has developed dramatically and located a critical position in tourism as the new member.Although it commenced not long ago,it is developing dramatically.The mentioned tourism proceeded sur...Nowadays the farm-based tour has developed dramatically and located a critical position in tourism as the new member.Although it commenced not long ago,it is developing dramatically.The mentioned tourism proceeded surprisingly since the late of 1990s for the fulfillment of "Golden Week" holiday.More and more citizens tend to divert themselves by agritainment after their competitive and tensional working experience.The same tourism is also moving forwards in the city,Dingxi.It is an urgent issue for Dingxi to grasp the opportunity to develop and benefit from agritainment,subsequently to challenge the competition.展开更多
基金supported by the Open Project of Xiangjiang Laboratory (22XJ02003)Scientific Project of the National University of Defense Technology (NUDT)(ZK21-07, 23-ZZCX-JDZ-28)+1 种基金the National Science Fund for Outstanding Young Scholars (62122093)the National Natural Science Foundation of China (72071205)。
文摘Traditional expert-designed branching rules in branch-and-bound(B&B) are static, often failing to adapt to diverse and evolving problem instances. Crafting these rules is labor-intensive, and may not scale well with complex problems.Given the frequent need to solve varied combinatorial optimization problems, leveraging statistical learning to auto-tune B&B algorithms for specific problem classes becomes attractive. This paper proposes a graph pointer network model to learn the branch rules. Graph features, global features and historical features are designated to represent the solver state. The graph neural network processes graph features, while the pointer mechanism assimilates the global and historical features to finally determine the variable on which to branch. The model is trained to imitate the expert strong branching rule by a tailored top-k Kullback-Leibler divergence loss function. Experiments on a series of benchmark problems demonstrate that the proposed approach significantly outperforms the widely used expert-designed branching rules. It also outperforms state-of-the-art machine-learning-based branch-and-bound methods in terms of solving speed and search tree size on all the test instances. In addition, the model can generalize to unseen instances and scale to larger instances.
基金Sponsored by Characteristic Innovation Project of Guangdong Department of Education(2016WTSCX119)The 2017 Discipline Co-construction Project of“13th Five-Year Plan”of Philosophy and Social Sciences in Guangdong Province(GD17XGL62)。
文摘The development types of traditional village B&B can be divided into spontaneous style,scenic area driven style and new rural construction led style.The development of B&B in Jinlin Village has certain livable environment and resource conditions,good location,profound cultural heritage and government support.It has experienced three stages of construction,namely scenic spot development,civilized village and new countryside.The development type of B&B in Jinlin Village belongs to the dual type of scenic spot driving and new countryside construction.However,over construction has negative impact on the development of B&B.Four planning strategies are put forward,including protecting and activating the traditional houses,increasing the green space to isolate and buffer the impact of new houses on traditional dwellings,opening up new lakeside residential area,and fully protecting and utilizing peripheral farmlands.
基金Supported by Young Scholar Project of National Natural Science Foundation(71303086)Young Scholar Project of Humanities and Social Science Foundation of Ministry of Education(12YJC630168)
文摘Based on the theory of consumer behavior,with reference to theories of the tourism,according to EBM model in consumer behavior model,it analyzed the agritainment consumption behavior through building a three-stage model for the agritainment consumption behavior,namely decision stage before travel,travel stage,and evaluation stage after consumption. Taking the urban residents of Huangpi District of Wuhan City as the research objects,using SPSS software,it designed the questionnaire and conducted the survey of agritainment tourists,and analyzed basic characteristics of tourists and their consumption behavior characteristics. In conclusion,the age of tourists has a significant influence on their choice of destination,information channel,and entertainment activities. It is recommended that operators of agritainment can set up entertainment activities according to different age of tourists and transmit information to the right tourists in the right place.
文摘Based on the development prospect of the industry of keeping in good health and caring for the senior and practical exploration on the Lishui Citys construction of "Health Blessed Land" in Yangtze River Delta, the position, function and facing problems of agritainment in the system of industrial economy of keeping in good health and caring for the senior in Lishui City. From the view of the industry integration, this paper puts forward the new strategies of developing agritainment in terms of design concepts at the top level, guarantee conditions in the government, layout strategies stressing on resources, target assessment focusing on nourishing of life, the basic promoting connotation.
基金Under the auspices of National Social Science Foundation of China (No.21BJY202)。
文摘There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial carrier.Accurately identifying the differences in spatial characteristics and influencing factors of each type,is essential for creating urban and rural B&B agglomeration areas.This study used density-based spatial clustering of applications with noise(DBSCAN)and the multi-scale geographically weighted regression(MGWR)model to explore similarities and differences in the spatial distribution patterns and influencing factors for urban and rural B&Bs on the Jiaodong Peninsula of China from 2010 to 2022.The results showed that:1)both urban and rural B&Bs in Jiaodong Peninsula went through three stages:a slow start from 2010 to 2015,rapid development from 2015 to 2019,and hindered development from 2019 to 2022.However,urban B&Bs demonstrated a higher development speed and agglomeration intensity,leading to an increasingly evident trend of uneven development between the two sectors.2)The clustering scale of both urban and rural B&Bs continued to expand in terms of quantity and volume.Urban B&B clusters characterized by a limited number,but a higher likelihood of transitioning from low-level to high-level clusters.While the number of rural B&B clusters steadily increased over time,their clustering scale was comparatively lower than that of urban B&Bs,and they lacked the presence of high-level clustering.3)In terms of development direction,urban B&B clusters exhibited a relatively stable pattern and evolved into high-level clustering centers within the main urban areas.Conversely,rural B&Bs exhibited a more pronounced spatial diffusion effect,with clusters showing a trend of multi-center development along the coastline.4)Transport emerged as a common influencing factor for both urban and rural B&Bs,with the density of road network having the strongest explanatory power for their spatial distribution.In terms of differences,population agglomeration had a positive impact on the distribution of urban B&Bs and a negative effect on the distribution of rural B&Bs.Rural B&Bs clustering was more influenced by tourism resources compared with urban B&Bs,but increasing tourist stay duration remains an urgent issue to be addressed.The findings of this study could provide a more precise basis for government planning and management of urban and rural B&B agglomeration areas.
文摘Nowadays the farm-based tour has developed dramatically and located a critical position in tourism as the new member.Although it commenced not long ago,it is developing dramatically.The mentioned tourism proceeded surprisingly since the late of 1990s for the fulfillment of "Golden Week" holiday.More and more citizens tend to divert themselves by agritainment after their competitive and tensional working experience.The same tourism is also moving forwards in the city,Dingxi.It is an urgent issue for Dingxi to grasp the opportunity to develop and benefit from agritainment,subsequently to challenge the competition.
