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
The rapid development of Internet has led to the explosion of information sharing, and how to supervise the sharing is a main research topic on current Internet. Aiming at the disadvantage that the current Peer-to-Pee...The rapid development of Internet has led to the explosion of information sharing, and how to supervise the sharing is a main research topic on current Internet. Aiming at the disadvantage that the current Peer-to-Peer (P2P) is hard to manage and control, this paper presents a Session Initial Protocol (SIP)-based P2P network of three-level architecture. SIP middleware is introduced to the middle level of the three-layer architecture. By the connection function of the SIP signaling, the P2P transmission on media-level can be controlled. Using SIP’s register and authentication function, the manage layer can manage the whole P2P network. Based on the aforementioned architecture, this paper investigates the grouping strategy on a live broadcast application in P2P network. Combined with the function of SIP register, the paper works on several grouping strategies, sets up models to manage users by grouping them, presents a weight-based K-means IP address grouping algorithm, and realizes it. The experiment shows that the grouping strategy presented in this paper can solve the problem of group sharing of network resource, and can realize the efficient-sharing, reasonable-distributing of network resource.展开更多
As a large private company starting from feed-processing industry, the East Hope Group has entered the aluminum industry. During the period of less than four years, it has completed two big electrolyticaluminum smelte...As a large private company starting from feed-processing industry, the East Hope Group has entered the aluminum industry. During the period of less than four years, it has completed two big electrolyticaluminum smelters and started the construction of a project of oxide of alumina. With its rapid speed, advanced technology and equipment, and high efficiency, the company has created a miracle in aluminum industry. From the viewpoint of strategic management, the author analyzes the strategic thinking of its entry into the aluminum industry; the strategic measures to build the company into the most competitive enterprise in this industry, and how to maintain a sustainable competitive advantage. Meanwhile, the paper plays an important reference role for the analysis of the private economy, and the enterprises with diversified thinking and those wishing to expand aggressively.展开更多
Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seven...Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seventeen functional groups(B, D, E, F, G, J, Lo, MP, P, S1, T, W1, W2, X1, X2, Xph, Y) were identified based on 34 species. The dominant groups were: J/B/P/D in dry season, X1/J/Xph/G/T in normal season and J in flood season. Phytoplankton abundance ranged from 5.33×10~4 cells/L to 3.65×10~7 cells/L, with the highest value occurring in flood season and lowest in dry season. The vertical profi le of dominant groups showed little differentiation except for P, which dominated surface layers over 20 m as a result of mixing water masses and higher transparency during dry season. However, the surface waters presented higher values of phytoplankton abundance than other layers, possibly because of greater irradiance. The significant explaining variables and their ability to describe the spatial distribution of the phytoplankton community in RDA diff ered seasonally as follows: dry season, NH4-N, NO_3-N, NO_2-N, TN:TP ratio and transparency(SD); normal season, temperature(WT), water depth, TN, NH4-N and NO_3-N; flood season, WT, water depth, NO_3-N and NO_2-N. Furthermore, nitrogen, water temperature, SD and water depth were significant variables explaining the variance of phytoplankton communities when datasets included all samples. The results indicated that water physical conditions and hydrology were important in phytoplankton community dynamics, and nitrogen was more important than phosphorus in modifying phytoplankton communities. Seasonal differences in the relationship between the environment and phytoplankton community should be considered in water quality management.展开更多
I.Lenovo: refocus on PC operation On December 8th, 2004, Lenovo consummated a deal with IBM whereby Lenovo was to acquire IBM’s desktop and laptop PC unit and its R&D and procurement operations worldwide for the...I.Lenovo: refocus on PC operation On December 8th, 2004, Lenovo consummated a deal with IBM whereby Lenovo was to acquire IBM’s desktop and laptop PC unit and its R&D and procurement operations worldwide for the sum of US$1.25 billion. On May 1st 2005, Lenovo completed its acquisition of IBM’s PC Unit. "Using an analogy, our enterprise is well likened to a tortoise but our foreign competitor is more like a rabbit. Instead of racing against the rabbit heads-on, we would rather ride on its back and let it carry us forward," said former Lenovo Chairman Liu Chuanzhi.展开更多
Purpose-As intelligent technology advances,practical applications often involve data with multiple labels.Therefore,multi-label feature selection methods have attracted much attention to extract valuable information.H...Purpose-As intelligent technology advances,practical applications often involve data with multiple labels.Therefore,multi-label feature selection methods have attracted much attention to extract valuable information.However,current methods tend to lack interpretability when evaluating the relationship between different types of variables without considering the potential causal relationship.Design/methodology/approach-To address the above problems,we propose an ensemble causal feature selection method based on mutual information and group fusion strategy(CMIFS)for multi-label data.First,the causal relationship between labels and features is analyzed by local causal structure learning,respectively,to obtain a causal feature set.Second,we eliminate false positive features from the obtained feature set using mutual information to improve the feature subset reliability.Eventually,we employ a group fusion strategy to fuse the obtained feature subsets from multiple data sub-space to enhance the stability of the results.Findings-Experimental comparisons are performed on six datasets to validate that our proposal can enhance the interpretation and robustness of the model compared with other methods in different metrics.Furthermore,the statistical analyses further validate the effectiveness of our approach.Originality/value-The present study makes a noteworthy contribution to proposing a causal feature selection approach based on mutual information to obtain an approximate optimal feature subset for multilabel data.Additionally,our proposal adopts the group fusion strategy to guarantee the robustness of the obtained feature subset.展开更多
1-Isoquinolin-1(2H)-one skeleton exists widely in natural products,pharmaceuticals and materials.We disclose here a fluorine effect and catalyst cooperatively induced regioselective or regiospecific 3,4-functionalizat...1-Isoquinolin-1(2H)-one skeleton exists widely in natural products,pharmaceuticals and materials.We disclose here a fluorine effect and catalyst cooperatively induced regioselective or regiospecific 3,4-functionalization of unsymmetric 2-CF_(3)-1,3-enynes.The presence of trifluoromethyl group is determinable for the regioselectivity.When the CF_(3) group was replaced with the methyl or amide group,the regioselectivity decreased to a ratio of 1.3:1 or 1:1.7,respectively.For alkyl substitutedβ-CF_(3)-1,3-enynes,a regiospecificity was obtained.This strategy features excellent regioselectivity,broad substrate scope and high functional group tolerance.Mechanistic studies showed that C–H bond activation is the rate-limiting step.展开更多
Herein,an unprecedented nickel-catalyzed regioselective hydroalkynylation of unsymmetrical internal alkynes was realized with steric hindered resistance selectivity via the cyano-directing group strategy.Significantly...Herein,an unprecedented nickel-catalyzed regioselective hydroalkynylation of unsymmetrical internal alkynes was realized with steric hindered resistance selectivity via the cyano-directing group strategy.Significantly,the resulting 1,3-enyne products could be effectively employed in the synthesis of novel nitrogen-containing tricyclics compounds,that provided the potential candidate compound 8a(IC_(50)=2.6—6.1μmol/L)for the anti-tumor cell proliferation activity.Therefore,this work not only improves the transition-metal-catalyzed hydroalkynylation strategy of internal alkynes,but also exhibits versatility of 1,3-enynes in the construction of the complex bioactive chemical space.展开更多
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.
基金Supported in part by the Hi-Tech R&D Program (863) of China (2006AA01Z444)the CNGI 2006 Application Demonstration Program (The IPv6 Distributed Multi-media Communication System Based On SIP and WISI/WIMAX )Tsinghua-Microsoft Key Laboratory Fund Project
文摘The rapid development of Internet has led to the explosion of information sharing, and how to supervise the sharing is a main research topic on current Internet. Aiming at the disadvantage that the current Peer-to-Peer (P2P) is hard to manage and control, this paper presents a Session Initial Protocol (SIP)-based P2P network of three-level architecture. SIP middleware is introduced to the middle level of the three-layer architecture. By the connection function of the SIP signaling, the P2P transmission on media-level can be controlled. Using SIP’s register and authentication function, the manage layer can manage the whole P2P network. Based on the aforementioned architecture, this paper investigates the grouping strategy on a live broadcast application in P2P network. Combined with the function of SIP register, the paper works on several grouping strategies, sets up models to manage users by grouping them, presents a weight-based K-means IP address grouping algorithm, and realizes it. The experiment shows that the grouping strategy presented in this paper can solve the problem of group sharing of network resource, and can realize the efficient-sharing, reasonable-distributing of network resource.
文摘As a large private company starting from feed-processing industry, the East Hope Group has entered the aluminum industry. During the period of less than four years, it has completed two big electrolyticaluminum smelters and started the construction of a project of oxide of alumina. With its rapid speed, advanced technology and equipment, and high efficiency, the company has created a miracle in aluminum industry. From the viewpoint of strategic management, the author analyzes the strategic thinking of its entry into the aluminum industry; the strategic measures to build the company into the most competitive enterprise in this industry, and how to maintain a sustainable competitive advantage. Meanwhile, the paper plays an important reference role for the analysis of the private economy, and the enterprises with diversified thinking and those wishing to expand aggressively.
基金Supported by the Department of Science and Technology of Guizhou Province(Nos.[2014]7001,[2015]2001,[2015]10)the Water Resources Department of Guizhou Province(No.KT201401)
文摘Phytoplankton and environment factors were investigated in 2015 and phytoplankton functional groups were used to understand their temporal and spatial distribution and their driving factors in Wanfeng Reservoir. Seventeen functional groups(B, D, E, F, G, J, Lo, MP, P, S1, T, W1, W2, X1, X2, Xph, Y) were identified based on 34 species. The dominant groups were: J/B/P/D in dry season, X1/J/Xph/G/T in normal season and J in flood season. Phytoplankton abundance ranged from 5.33×10~4 cells/L to 3.65×10~7 cells/L, with the highest value occurring in flood season and lowest in dry season. The vertical profi le of dominant groups showed little differentiation except for P, which dominated surface layers over 20 m as a result of mixing water masses and higher transparency during dry season. However, the surface waters presented higher values of phytoplankton abundance than other layers, possibly because of greater irradiance. The significant explaining variables and their ability to describe the spatial distribution of the phytoplankton community in RDA diff ered seasonally as follows: dry season, NH4-N, NO_3-N, NO_2-N, TN:TP ratio and transparency(SD); normal season, temperature(WT), water depth, TN, NH4-N and NO_3-N; flood season, WT, water depth, NO_3-N and NO_2-N. Furthermore, nitrogen, water temperature, SD and water depth were significant variables explaining the variance of phytoplankton communities when datasets included all samples. The results indicated that water physical conditions and hydrology were important in phytoplankton community dynamics, and nitrogen was more important than phosphorus in modifying phytoplankton communities. Seasonal differences in the relationship between the environment and phytoplankton community should be considered in water quality management.
文摘I.Lenovo: refocus on PC operation On December 8th, 2004, Lenovo consummated a deal with IBM whereby Lenovo was to acquire IBM’s desktop and laptop PC unit and its R&D and procurement operations worldwide for the sum of US$1.25 billion. On May 1st 2005, Lenovo completed its acquisition of IBM’s PC Unit. "Using an analogy, our enterprise is well likened to a tortoise but our foreign competitor is more like a rabbit. Instead of racing against the rabbit heads-on, we would rather ride on its back and let it carry us forward," said former Lenovo Chairman Liu Chuanzhi.
基金supported by the Nature Science Foundation of China(Grant No.62376114)the Nature Science Foundation of Fujian Province(Grant No.2021J011004,No.2021J011002)+1 种基金the Ministry of Education Industry-University-Research Innovation Program(Grant No.2021LDA09003)the Department of Education Foundation of Fujian Province(No.JAT210266)。
文摘Purpose-As intelligent technology advances,practical applications often involve data with multiple labels.Therefore,multi-label feature selection methods have attracted much attention to extract valuable information.However,current methods tend to lack interpretability when evaluating the relationship between different types of variables without considering the potential causal relationship.Design/methodology/approach-To address the above problems,we propose an ensemble causal feature selection method based on mutual information and group fusion strategy(CMIFS)for multi-label data.First,the causal relationship between labels and features is analyzed by local causal structure learning,respectively,to obtain a causal feature set.Second,we eliminate false positive features from the obtained feature set using mutual information to improve the feature subset reliability.Eventually,we employ a group fusion strategy to fuse the obtained feature subsets from multiple data sub-space to enhance the stability of the results.Findings-Experimental comparisons are performed on six datasets to validate that our proposal can enhance the interpretation and robustness of the model compared with other methods in different metrics.Furthermore,the statistical analyses further validate the effectiveness of our approach.Originality/value-The present study makes a noteworthy contribution to proposing a causal feature selection approach based on mutual information to obtain an approximate optimal feature subset for multilabel data.Additionally,our proposal adopts the group fusion strategy to guarantee the robustness of the obtained feature subset.
基金supported by National Natural Science Founda:tion of China(22461002,22308061,22305046)Natural Science Foundation(NSF)of Jiangxi Province(20224BAB213011,20242BAB20110,20224BAB213012)+1 种基金High-Level and Highly Demanded Overseas Talent Programs of Jiangxi Province(20232BCJ25050)Gannan Normal University Start-up Fund(BSJJ202109).
文摘1-Isoquinolin-1(2H)-one skeleton exists widely in natural products,pharmaceuticals and materials.We disclose here a fluorine effect and catalyst cooperatively induced regioselective or regiospecific 3,4-functionalization of unsymmetric 2-CF_(3)-1,3-enynes.The presence of trifluoromethyl group is determinable for the regioselectivity.When the CF_(3) group was replaced with the methyl or amide group,the regioselectivity decreased to a ratio of 1.3:1 or 1:1.7,respectively.For alkyl substitutedβ-CF_(3)-1,3-enynes,a regiospecificity was obtained.This strategy features excellent regioselectivity,broad substrate scope and high functional group tolerance.Mechanistic studies showed that C–H bond activation is the rate-limiting step.
基金supported by the National Natural Science Foundation of China(22361003,82260676)Talent Project of Jiangxi Province(jxsq2019101065)+2 种基金the Jiangxi Provincial Natural Science Foundation(20224BAB216005,20232BAB216131)the Science and Technology Projects of Ganzhou(202101094462,2023PNS26854)The Start-up Fund of Gannan Medical University.
文摘Herein,an unprecedented nickel-catalyzed regioselective hydroalkynylation of unsymmetrical internal alkynes was realized with steric hindered resistance selectivity via the cyano-directing group strategy.Significantly,the resulting 1,3-enyne products could be effectively employed in the synthesis of novel nitrogen-containing tricyclics compounds,that provided the potential candidate compound 8a(IC_(50)=2.6—6.1μmol/L)for the anti-tumor cell proliferation activity.Therefore,this work not only improves the transition-metal-catalyzed hydroalkynylation strategy of internal alkynes,but also exhibits versatility of 1,3-enynes in the construction of the complex bioactive chemical space.
