In cooperative multiagent systems, to learn the optimal policies of multiagents is very difficult. As the numbers of states and actions increase exponentially with the number of agents, their action policies become mo...In cooperative multiagent systems, to learn the optimal policies of multiagents is very difficult. As the numbers of states and actions increase exponentially with the number of agents, their action policies become more intractable. By learning these value functions, an agent can learn its optimal action policies for a task. If a task can be decomposed into several subtasks and the agents have learned the optimal value functions for each subtask, this knowledge can be helpful for the agents in learning the optimal action policies for the whole task when they are acting simultaneously. When merging the agents’ independently learned optimal value functions, a novel multiagent online reinforcement learning algorithm LU-Q is proposed. By applying a transformation to the individually learned value functions, the constraints on the optimal value functions of each subtask are loosened. In each learning iteration process in algorithm LU-Q, the agents’ joint action set in a state is processed. Some actions of that state are pruned from the available action set according to the defined multiagent value function in LU-Q. As the items of the available action set of each state are reduced gradually in the iteration process of LU-Q, the convergence of the value functions is accelerated. LU-Q’s effectiveness, soundness and convergence are analyzed, and the experimental results show that the learning performance of LU-Q is better than the performance of standard Q learning.展开更多
Scientific research on snow avalanches is relatively modem, yet in constant and rapid evolution, as the multiple disciplines involved in its development will, in turn, become more specialized and more technical. Paten...Scientific research on snow avalanches is relatively modem, yet in constant and rapid evolution, as the multiple disciplines involved in its development will, in turn, become more specialized and more technical. Patents are part of research and knowledge production. The scientific community and policy makers are increasingly interested in production of knowledge collaboratively. Almost all of the research being conducted on snow avalanches uses technology, technique or instrumentation. One main objective of this study is to draw from the literature the many technologies, techniques and instrumentations that are being used in research related to avalanches. Thus, a textual analysis of the most significant literature in the field of snow avalanches was done. In this analysis, techniques, technologies and instrumentations have emerged. A patent search has been done in databases. Subsequently, patents were conceptualized. The proportion of applicants for patents is higher in industry than in universities. The measure of exploration of the ongoing sociocognitive transformations of science and technology systems presents a useful tool to conduct a study to explore these transformations. It would be interesting for the scientific community, but also for the industry, to elaborate concept mapping when applied to avalanche research, which would help in determining referents.展开更多
The paper examined the state of GIS （geographic information systems） knowledge and adoption in Nigeria, identified factors affecting its implementation and finally discussed methods of enhancing its use in Nigeria. ...The paper examined the state of GIS （geographic information systems） knowledge and adoption in Nigeria, identified factors affecting its implementation and finally discussed methods of enhancing its use in Nigeria. Administrative records of some institutions and information obtained from published articles in journals and text books were used for the study. Records indicate that GIS is relatively young in Nigeria and in terms of development, it is at its youthful stage. The adoption and use of GIS is low at both Federal and State Government levels. However, factors such as, lack of political will, shortage of experts to train the professionals, lack of standardization of digital data, database development and management problems, institutional constraints, security implications of digital maps and poor funding have been inhibiting full adoption, implementation and use of GIS in Nigeria. There is the need to develop a GIS vision in the country and government should formulate policy and create enabling environment for the adoption and implementation of the new technology.展开更多
Cryptography is an important tool in the design and implementation of e-voting schemes since it can provide verifiability, which is not provided in the traditional voting. But in the real life, most voters can neither...Cryptography is an important tool in the design and implementation of e-voting schemes since it can provide verifiability, which is not provided in the traditional voting. But in the real life, most voters can neither understand the profound theory of cryptography nor perform the complicated cryptographic computation. An e-voting system is presented in this paper to leverage the use of cryptography. It combines the advantages of voting scheme of Moran-Naor and voting scheme based on homomorphic encryption. It makes use of the cryptographic technique, but it hides the details of cryptographic computation from voters. Compared with voting scheme of Moran-Naor, the new system has three advantages: the ballots can be recovered when the voting machine breaks down, the costly cut-and-choose zero-knowledge proofs for shuffling votes made by the voting machine are avoided and the partial tally result in each voting machine can be kept secret.展开更多
文摘In cooperative multiagent systems, to learn the optimal policies of multiagents is very difficult. As the numbers of states and actions increase exponentially with the number of agents, their action policies become more intractable. By learning these value functions, an agent can learn its optimal action policies for a task. If a task can be decomposed into several subtasks and the agents have learned the optimal value functions for each subtask, this knowledge can be helpful for the agents in learning the optimal action policies for the whole task when they are acting simultaneously. When merging the agents’ independently learned optimal value functions, a novel multiagent online reinforcement learning algorithm LU-Q is proposed. By applying a transformation to the individually learned value functions, the constraints on the optimal value functions of each subtask are loosened. In each learning iteration process in algorithm LU-Q, the agents’ joint action set in a state is processed. Some actions of that state are pruned from the available action set according to the defined multiagent value function in LU-Q. As the items of the available action set of each state are reduced gradually in the iteration process of LU-Q, the convergence of the value functions is accelerated. LU-Q’s effectiveness, soundness and convergence are analyzed, and the experimental results show that the learning performance of LU-Q is better than the performance of standard Q learning.
文摘Scientific research on snow avalanches is relatively modem, yet in constant and rapid evolution, as the multiple disciplines involved in its development will, in turn, become more specialized and more technical. Patents are part of research and knowledge production. The scientific community and policy makers are increasingly interested in production of knowledge collaboratively. Almost all of the research being conducted on snow avalanches uses technology, technique or instrumentation. One main objective of this study is to draw from the literature the many technologies, techniques and instrumentations that are being used in research related to avalanches. Thus, a textual analysis of the most significant literature in the field of snow avalanches was done. In this analysis, techniques, technologies and instrumentations have emerged. A patent search has been done in databases. Subsequently, patents were conceptualized. The proportion of applicants for patents is higher in industry than in universities. The measure of exploration of the ongoing sociocognitive transformations of science and technology systems presents a useful tool to conduct a study to explore these transformations. It would be interesting for the scientific community, but also for the industry, to elaborate concept mapping when applied to avalanche research, which would help in determining referents.
文摘The paper examined the state of GIS （geographic information systems） knowledge and adoption in Nigeria, identified factors affecting its implementation and finally discussed methods of enhancing its use in Nigeria. Administrative records of some institutions and information obtained from published articles in journals and text books were used for the study. Records indicate that GIS is relatively young in Nigeria and in terms of development, it is at its youthful stage. The adoption and use of GIS is low at both Federal and State Government levels. However, factors such as, lack of political will, shortage of experts to train the professionals, lack of standardization of digital data, database development and management problems, institutional constraints, security implications of digital maps and poor funding have been inhibiting full adoption, implementation and use of GIS in Nigeria. There is the need to develop a GIS vision in the country and government should formulate policy and create enabling environment for the adoption and implementation of the new technology.
基金the National Natural Science Foundation of China (No. 60673076)the National High Technology Research and Development Program (863)of China (No. 2008AA01Z403)
文摘Cryptography is an important tool in the design and implementation of e-voting schemes since it can provide verifiability, which is not provided in the traditional voting. But in the real life, most voters can neither understand the profound theory of cryptography nor perform the complicated cryptographic computation. An e-voting system is presented in this paper to leverage the use of cryptography. It combines the advantages of voting scheme of Moran-Naor and voting scheme based on homomorphic encryption. It makes use of the cryptographic technique, but it hides the details of cryptographic computation from voters. Compared with voting scheme of Moran-Naor, the new system has three advantages: the ballots can be recovered when the voting machine breaks down, the costly cut-and-choose zero-knowledge proofs for shuffling votes made by the voting machine are avoided and the partial tally result in each voting machine can be kept secret.
