In order to discover genes capable of catalyzing the reductive immobilization of toxic chromate and uranyl ions, we have created a T7 bacteriophage library containing cDNA from environmental microbes (i.e., Geobacter ...In order to discover genes capable of catalyzing the reductive immobilization of toxic chromate and uranyl ions, we have created a T7 bacteriophage library containing cDNA from environmental microbes (i.e., Geobacter sulfurreducens and Shewanella oneidensis MR-1) that are known to mediate the reduction of chromate and uranyl ions. After three rounds of screening, ten bacteriophage mutants were found to mediate the NADH-dependent reduction of chromate and uranyl ions whose cDNA encodes polypeptide chains ranging 14 to 73 amino acids in length. All identified sequences contain disordered structural motifs similar to the β-amyloid peptide (Aβ) known to promote aggregation and formation of high-affinity metal binding sites. Confirmation of this structural similarity involved phage display of the 42 amino-acid Aβ-peptides that have been found to catalyze the NADH-dependent reduction of both chromate and uranyl ions. Transmission electron microscopy (TEM) and X-ray absorption near edge structure (XANES) measurements confirm that reduced uranium is present on the surface of bacteriophage expressing the Aβ-peptide. The surface-displayed Aβ-like peptide on bacteriophage has the potential to couple naturally occurring electron transfer shuttles present in soils to promote economically viable remediation of contaminated sites containing toxic chromate and uranyl ions.展开更多
With the rapid growth of flight flow,the workload of controllers is increasing daily,and handling flight conflicts is the main workload.Therefore,it is necessary to provide more efficient conflict resolution decision-...With the rapid growth of flight flow,the workload of controllers is increasing daily,and handling flight conflicts is the main workload.Therefore,it is necessary to provide more efficient conflict resolution decision-making support for controllers.Due to the limitations of existing methods,they have not been widely used.In this paper,a Deep Reinforcement Learning(DRL)algorithm is proposed to resolve multi-aircraft flight conflict with high solving efficiency.First,the characteristics of multi-aircraft flight conflict problem are analyzed and the problem is modeled based on Markov decision process.Thus,the Independent Deep Q Network(IDQN)algorithm is used to solve the model.Simultaneously,a’downward-compatible’framework that supports dynamic expansion of the number of conflicting aircraft is designed.The model ultimately shows convergence through adequate training.Finally,the test conflict scenarios and indicators were used to verify the validity.In 700 scenarios,85.71%of conflicts were successfully resolved,and 71.51%of aircraft can reach destinations within 150 s around original arrival times.By contrast,conflict resolution algorithm based on DRL has great advantages in solution speed.The method proposed offers the possibility of decision-making support for controllers and reduce workload of controllers in future high-density airspace environment.展开更多
Managing software packages in a scientific computing environment is a challenging task, especially in the case of heterogeneous systems. It is error prone when installing and updating software packages in a sophistica...Managing software packages in a scientific computing environment is a challenging task, especially in the case of heterogeneous systems. It is error prone when installing and updating software packages in a sophisticated computing environment. Testing and performance evaluation in an on-the-fly manner is also a troublesome task for a production system. In this paper, we discuss a package management scheme based on containers. The newly developed method can ease the maintenance complexity and reduce human mistakes. We can benefit from the self-containing and isolation features of container technologies for maintaining the software packages among intricately connected clusters. By deploying the Super Computing application Strore（SCStore） over the WAN connected world-largest clusters, it proved that it can greatly reduce the effort for maintaining the consistency of software environment and bring benefit to achieve automation.展开更多
With the rapid development of 3D Digital City, the focus of research has shifted from 3D city modeling and geo-database construction to 3D geo-database service and maintenance. The frequent modifications on geometry, ...With the rapid development of 3D Digital City, the focus of research has shifted from 3D city modeling and geo-database construction to 3D geo-database service and maintenance. The frequent modifications on geometry, texture, attribute, and topology present a great challenge to the 3D geo-database updating.This article proposes an event-driven spatiotemporal database model (ESDM) that combines the historical and present 3D city models with the semantic classification and state expression, triggered by changing events predefined. In addition, a corresponding dynamic updating method based on adaptive matching algorithm is presented to perform the dynamic updating operation for the complex 3D city models automatically, according to the compound matching of semantics, attributes, and spatial locations. finally, the validity and feasibility of the proposed ESDM and its updating method are demonstrated through a 3D geo-database with more than 1.5 million 3D city models.展开更多
文摘In order to discover genes capable of catalyzing the reductive immobilization of toxic chromate and uranyl ions, we have created a T7 bacteriophage library containing cDNA from environmental microbes (i.e., Geobacter sulfurreducens and Shewanella oneidensis MR-1) that are known to mediate the reduction of chromate and uranyl ions. After three rounds of screening, ten bacteriophage mutants were found to mediate the NADH-dependent reduction of chromate and uranyl ions whose cDNA encodes polypeptide chains ranging 14 to 73 amino acids in length. All identified sequences contain disordered structural motifs similar to the β-amyloid peptide (Aβ) known to promote aggregation and formation of high-affinity metal binding sites. Confirmation of this structural similarity involved phage display of the 42 amino-acid Aβ-peptides that have been found to catalyze the NADH-dependent reduction of both chromate and uranyl ions. Transmission electron microscopy (TEM) and X-ray absorption near edge structure (XANES) measurements confirm that reduced uranium is present on the surface of bacteriophage expressing the Aβ-peptide. The surface-displayed Aβ-like peptide on bacteriophage has the potential to couple naturally occurring electron transfer shuttles present in soils to promote economically viable remediation of contaminated sites containing toxic chromate and uranyl ions.
基金supported by Safety Ability Project of Civil Aviation Administration of China(No.TM 2018-5-1/2)the Open Foundation project of The Graduate Student Innovation Base,China(Laboratory)of Nanjing University of Aeronautics and Astronautics,China(No.kfjj20190720)。
文摘With the rapid growth of flight flow,the workload of controllers is increasing daily,and handling flight conflicts is the main workload.Therefore,it is necessary to provide more efficient conflict resolution decision-making support for controllers.Due to the limitations of existing methods,they have not been widely used.In this paper,a Deep Reinforcement Learning(DRL)algorithm is proposed to resolve multi-aircraft flight conflict with high solving efficiency.First,the characteristics of multi-aircraft flight conflict problem are analyzed and the problem is modeled based on Markov decision process.Thus,the Independent Deep Q Network(IDQN)algorithm is used to solve the model.Simultaneously,a’downward-compatible’framework that supports dynamic expansion of the number of conflicting aircraft is designed.The model ultimately shows convergence through adequate training.Finally,the test conflict scenarios and indicators were used to verify the validity.In 700 scenarios,85.71%of conflicts were successfully resolved,and 71.51%of aircraft can reach destinations within 150 s around original arrival times.By contrast,conflict resolution algorithm based on DRL has great advantages in solution speed.The method proposed offers the possibility of decision-making support for controllers and reduce workload of controllers in future high-density airspace environment.
基金supported by the National Key R&D Program of China(No.2016YFA0602100)the National Natural Science Foundation of China(No.91530323)Open Fund of Key Laboratory of Data Analysis and Applications,SOA(No.LDAA-2014-03)
文摘Managing software packages in a scientific computing environment is a challenging task, especially in the case of heterogeneous systems. It is error prone when installing and updating software packages in a sophisticated computing environment. Testing and performance evaluation in an on-the-fly manner is also a troublesome task for a production system. In this paper, we discuss a package management scheme based on containers. The newly developed method can ease the maintenance complexity and reduce human mistakes. We can benefit from the self-containing and isolation features of container technologies for maintaining the software packages among intricately connected clusters. By deploying the Super Computing application Strore（SCStore） over the WAN connected world-largest clusters, it proved that it can greatly reduce the effort for maintaining the consistency of software environment and bring benefit to achieve automation.
基金This study is supported by the National Natural Science Foundation of China [grant number 41301439], the Open Research Fund of State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing [grant number 11I01], [grant number 15I03], and the Guangdong Province Science and Technology Plan Project (grant number 2015A010103010)
文摘With the rapid development of 3D Digital City, the focus of research has shifted from 3D city modeling and geo-database construction to 3D geo-database service and maintenance. The frequent modifications on geometry, texture, attribute, and topology present a great challenge to the 3D geo-database updating.This article proposes an event-driven spatiotemporal database model (ESDM) that combines the historical and present 3D city models with the semantic classification and state expression, triggered by changing events predefined. In addition, a corresponding dynamic updating method based on adaptive matching algorithm is presented to perform the dynamic updating operation for the complex 3D city models automatically, according to the compound matching of semantics, attributes, and spatial locations. finally, the validity and feasibility of the proposed ESDM and its updating method are demonstrated through a 3D geo-database with more than 1.5 million 3D city models.
