A number of contingencies simulated during dynamic security assessment do not generate unacceptable values of power system state variables, due to their small influence on system operation. Their exclusion from the se...A number of contingencies simulated during dynamic security assessment do not generate unacceptable values of power system state variables, due to their small influence on system operation. Their exclusion from the set of contingencies to be simulated in the security assessment would achieve a significant reduction in computation time. This paper defines a critical contingencies selection method for on-line dynamic security assessment. The selection method results from an off-line dynamical analysis, which covers typical scenarios and also covers various related aspects like frequency, voltage, and angle analyses among others. Indexes measured over these typical scenarios are used to train neural networks, capable of performing on-line estimation of a critical contingencies list according to the system state.展开更多
Public security emergency is a public crisis event, and we cannot anticipate the specific time, actual scale, specific situation and influence depth of emergencies. If the emergencies are not under control, the crisis...Public security emergency is a public crisis event, and we cannot anticipate the specific time, actual scale, specific situation and influence depth of emergencies. If the emergencies are not under control, the crisis will get worse and its destructive energy will be released quickly.Structure box is an invisible closed system which is constructed by local politics, economy, and culture. Namely, structure box is local social ecological environment. Structure box is a closed area which is full of anger. Therefore, in such environment with too much pressure, we need an outlet to release pressure. Anger is the social and psychological basis of the emotional resonance of onlooker, when the fuse incident occurred, so that the widespread anger in structure box will find the spotlight. The words and actions of the leaders in the informal group will produce a great social infection and circulatory response, and groups’ stirring will cause emotional resonance which is easy to burst. Thus, irrational behavior may caused by people. This processcan use five links to describe： occurrence of fuse events, information diffusion, emotional resonance, situational catalysis, control failure, and occurrence of public security emergency. This is the occurrence mechanism of public security emergency.展开更多
Homoploid hybrid speciation （HHS） involves the recombination of two differentiated genomes into a novel, func- tional one without a change in chromosome number. Theoretically, there are numerous ways for two parenta...Homoploid hybrid speciation （HHS） involves the recombination of two differentiated genomes into a novel, func- tional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recom- bine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these ＂hopeful monsters＂ of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic con- tributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions （competition, geography of the contact zones or the initial frequency of both parent spe- cies） might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puz- zle [Current Zoology 59 （5）： 667-674, 2013].展开更多
文摘A number of contingencies simulated during dynamic security assessment do not generate unacceptable values of power system state variables, due to their small influence on system operation. Their exclusion from the set of contingencies to be simulated in the security assessment would achieve a significant reduction in computation time. This paper defines a critical contingencies selection method for on-line dynamic security assessment. The selection method results from an off-line dynamical analysis, which covers typical scenarios and also covers various related aspects like frequency, voltage, and angle analyses among others. Indexes measured over these typical scenarios are used to train neural networks, capable of performing on-line estimation of a critical contingencies list according to the system state.
文摘Public security emergency is a public crisis event, and we cannot anticipate the specific time, actual scale, specific situation and influence depth of emergencies. If the emergencies are not under control, the crisis will get worse and its destructive energy will be released quickly.Structure box is an invisible closed system which is constructed by local politics, economy, and culture. Namely, structure box is local social ecological environment. Structure box is a closed area which is full of anger. Therefore, in such environment with too much pressure, we need an outlet to release pressure. Anger is the social and psychological basis of the emotional resonance of onlooker, when the fuse incident occurred, so that the widespread anger in structure box will find the spotlight. The words and actions of the leaders in the informal group will produce a great social infection and circulatory response, and groups’ stirring will cause emotional resonance which is easy to burst. Thus, irrational behavior may caused by people. This processcan use five links to describe： occurrence of fuse events, information diffusion, emotional resonance, situational catalysis, control failure, and occurrence of public security emergency. This is the occurrence mechanism of public security emergency.
文摘Homoploid hybrid speciation （HHS） involves the recombination of two differentiated genomes into a novel, func- tional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recom- bine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these ＂hopeful monsters＂ of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic con- tributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions （competition, geography of the contact zones or the initial frequency of both parent spe- cies） might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puz- zle [Current Zoology 59 （5）： 667-674, 2013].
