A review concerning the methods of studying and describing wave groups is presented in this paper. After analysing 78 field records collected in the Shijiu Port, China, the measured parameters of wave groups and some ...A review concerning the methods of studying and describing wave groups is presented in this paper. After analysing 78 field records collected in the Shijiu Port, China, the measured parameters of wave groups and some factors describing wave groupness and their variations are given. Moreover, these results are compared with those of theory.展开更多
The mafic dykes from the Paleoproterozoic Bomdila Group of metasedimentary rocks,Arunachal Pradesh,NE Lesser Himalaya,India have been analyzed for major and trace elements geochemistry essentially to understand their
In order to study the differences in algae species and their biomass in water bodies in a region, three reservoirs and two lakes at the center of Guanzhong Plain were chosen to identify algae functional groups, measur...In order to study the differences in algae species and their biomass in water bodies in a region, three reservoirs and two lakes at the center of Guanzhong Plain were chosen to identify algae functional groups, measure biomass, and assess water quality, from January2013 to December 2014. The water bodies represented different trophic levels： one oligotrophic, three mesotrophic, and one eutrophic. Based on the Reynolds’ functional groups, they had 10 groups in common—B, P, D, X1, M, MP, F, S1, J, and G, but the algae biomasses and proportions were different. In the oligotrophic reservoir, functional group B reached a peak biomass of 576 × 104 L-1, which accounted for 31.27%. In the eutrophic lake,functional group D reached a peak biomass of 3227 × 104 L-1, which accounted for only13.38%. When samples collected from other water bodies with similar trophic levels were compared, we found differences in the algae species functional groups. The potential reasons for the differences in algae functional group characteristics in the different water bodies in the region were water temperature and nutritional states.展开更多
Let G be an extension of a finite characteristically simple group by an abelian group or a finite simple group.It is shown that every Coleman automorphism of G is an inner automorphism.Interest in such automorphisms a...Let G be an extension of a finite characteristically simple group by an abelian group or a finite simple group.It is shown that every Coleman automorphism of G is an inner automorphism.Interest in such automorphisms arises from the study of the normalizer problem for integral group rings.展开更多
IN 1932, Stone [1] gave the first result concerning C<sub>0</sub> semigroups generated by an unbounded operator,which says that a linear operator is the infinitesimal generator of a C<sub>0</sub&g...IN 1932, Stone [1] gave the first result concerning C<sub>0</sub> semigroups generated by an unbounded operator,which says that a linear operator is the infinitesimal generator of a C<sub>0</sub> group of unitary operators on a Hilbert space if and only if it is skew-adjoint. This result has been applied extensively to linear partial differential equations （PDEs） with a law of conservation. Hille [2] then discovered the generation theorem of the Hille-Yosida type for a C<sub>0</sub> group on a Banach space. There are also some conditions under which a C<sub>0</sub> semigroup on a Banach space can be embedded in a C<sub>0</sub> group. We refer the readers to ref. [3] for details of the results mentioned above.展开更多
We give a lower bound of the Loewy length of the projective cover of the trivial module for the group algebra kG of a finite group G of Lie type defined over a finite field of odd characteristic p, where k is an arbit...We give a lower bound of the Loewy length of the projective cover of the trivial module for the group algebra kG of a finite group G of Lie type defined over a finite field of odd characteristic p, where k is an arbitrary field of characteristic p. The proof uses Auslander-Reiten theory.展开更多
Let G=Hol(H)be the holomorph of a finite group H.If there is a prime q dividing|H|such that every q-central automorphism of H is inner and Z(H)=1,then every Coleman automorphism of G is inner.In particular,the normali...Let G=Hol(H)be the holomorph of a finite group H.If there is a prime q dividing|H|such that every q-central automorphism of H is inner and Z(H)=1,then every Coleman automorphism of G is inner.In particular,the normalizer property holds for G.展开更多
Aims Inferring environmental conditions from characteristic patterns of plant co-occurrences can be crucial for the development of conservation strategies concerning secondary neotropical forests.However,nomethodologi...Aims Inferring environmental conditions from characteristic patterns of plant co-occurrences can be crucial for the development of conservation strategies concerning secondary neotropical forests.However,nomethodological agreement has been achieved so far regarding the identification and classification of characteristic groups of vascular plant species in the tropics.This study examines botanical and,in particular,statistical aspects to beconsidered in such analyses.Based on these,we propose a novel data-driven approach for the identification of characteristic plantco-oc currences in neotropical secondary mountain forests.Methods Floristic inventory data were gathered in secondary tropical mountain forests in Ecuador.Vegetation classification was performed by coupling locally adaptive isometric feature mapping,a non-linear ordination method and fuzzy-c-means clustering.This approach was designed for dealing with underlying non-linearities and uncertainties in the inventory data.Important Findings The results indicate that the applied non-linear mapping in combination with fuzzy classification of species occurrence allows an effective identification of characteristic groups of co-occurring species as fuzzy-defined clusters.The selected species indicated groups representing characteristic life-form distributions,as they correspond to various stages of forest regeneration.Combining the identified‘characteristic species groups’with meta-information derived from accompanying studies indicated that the clusters can also be related to habitat conditions.In conclusion,we identified species groups either characteristic of different stages of forest succession after clear-cutting or of impact by fire or a landslide.We expect that the proposed data-mining method will be useful for vegetation classification where no a priori knowledge is available.展开更多
Particle swarm optimization(PSO)is one of the popular stochastic optimization based on swarm intelligence algorithm.This simple and promising algorithm has applications in many research fields.In PSO,each particle can...Particle swarm optimization(PSO)is one of the popular stochastic optimization based on swarm intelligence algorithm.This simple and promising algorithm has applications in many research fields.In PSO,each particle can adjust its‘flying’according to its own flying experience and its companions’flying experience.This paper proposes a new PSO variant,called the statistically tracked PSO,which uses group statistical characteristics to update the velocity of the particle after certain iterations,thus avoiding localminima and helping particles to explore global optimum with an improved convergence.The performance of the proposed algorithm is tested on a deregulated automatic generation control problem in power systems and encouraging results are obtained.展开更多
文摘A review concerning the methods of studying and describing wave groups is presented in this paper. After analysing 78 field records collected in the Shijiu Port, China, the measured parameters of wave groups and some factors describing wave groupness and their variations are given. Moreover, these results are compared with those of theory.
文摘The mafic dykes from the Paleoproterozoic Bomdila Group of metasedimentary rocks,Arunachal Pradesh,NE Lesser Himalaya,India have been analyzed for major and trace elements geochemistry essentially to understand their
基金supported by the Ministry of Human Resources and Social Security of the People's Republic of China,Shaanxi Youth Science and Technology Star Project(No.2012KJXX-32)the National Natural Science Youth Fund(No.51008242)
文摘In order to study the differences in algae species and their biomass in water bodies in a region, three reservoirs and two lakes at the center of Guanzhong Plain were chosen to identify algae functional groups, measure biomass, and assess water quality, from January2013 to December 2014. The water bodies represented different trophic levels： one oligotrophic, three mesotrophic, and one eutrophic. Based on the Reynolds’ functional groups, they had 10 groups in common—B, P, D, X1, M, MP, F, S1, J, and G, but the algae biomasses and proportions were different. In the oligotrophic reservoir, functional group B reached a peak biomass of 576 × 104 L-1, which accounted for 31.27%. In the eutrophic lake,functional group D reached a peak biomass of 3227 × 104 L-1, which accounted for only13.38%. When samples collected from other water bodies with similar trophic levels were compared, we found differences in the algae species functional groups. The potential reasons for the differences in algae functional group characteristics in the different water bodies in the region were water temperature and nutritional states.
基金supported by the National Natural Science Foundation of China(Grant No.11871292).
文摘Let G be an extension of a finite characteristically simple group by an abelian group or a finite simple group.It is shown that every Coleman automorphism of G is an inner automorphism.Interest in such automorphisms arises from the study of the normalizer problem for integral group rings.
文摘IN 1932, Stone [1] gave the first result concerning C<sub>0</sub> semigroups generated by an unbounded operator,which says that a linear operator is the infinitesimal generator of a C<sub>0</sub> group of unitary operators on a Hilbert space if and only if it is skew-adjoint. This result has been applied extensively to linear partial differential equations （PDEs） with a law of conservation. Hille [2] then discovered the generation theorem of the Hille-Yosida type for a C<sub>0</sub> group on a Banach space. There are also some conditions under which a C<sub>0</sub> semigroup on a Banach space can be embedded in a C<sub>0</sub> group. We refer the readers to ref. [3] for details of the results mentioned above.
基金the Japan Society for Promotion of Science （JSPS）, Grant-in-Aid for Scientific Research （C）15K04776, 2015-2018, and by the CIB in EPFL. The second author was supported by the German Science Foundation （DFG） Scientific Priority Programme SPP-1489 ＂Algorithmic and Experimental Methods in Algebra, Geometry, and Number Theory＂.
文摘We give a lower bound of the Loewy length of the projective cover of the trivial module for the group algebra kG of a finite group G of Lie type defined over a finite field of odd characteristic p, where k is an arbitrary field of characteristic p. The proof uses Auslander-Reiten theory.
基金Supported by the National Natural Science Foundation of China(Grant No.11871292)。
文摘Let G=Hol(H)be the holomorph of a finite group H.If there is a prime q dividing|H|such that every q-central automorphism of H is inner and Z(H)=1,then every Coleman automorphism of G is inner.In particular,the normalizer property holds for G.
文摘Aims Inferring environmental conditions from characteristic patterns of plant co-occurrences can be crucial for the development of conservation strategies concerning secondary neotropical forests.However,nomethodological agreement has been achieved so far regarding the identification and classification of characteristic groups of vascular plant species in the tropics.This study examines botanical and,in particular,statistical aspects to beconsidered in such analyses.Based on these,we propose a novel data-driven approach for the identification of characteristic plantco-oc currences in neotropical secondary mountain forests.Methods Floristic inventory data were gathered in secondary tropical mountain forests in Ecuador.Vegetation classification was performed by coupling locally adaptive isometric feature mapping,a non-linear ordination method and fuzzy-c-means clustering.This approach was designed for dealing with underlying non-linearities and uncertainties in the inventory data.Important Findings The results indicate that the applied non-linear mapping in combination with fuzzy classification of species occurrence allows an effective identification of characteristic groups of co-occurring species as fuzzy-defined clusters.The selected species indicated groups representing characteristic life-form distributions,as they correspond to various stages of forest regeneration.Combining the identified‘characteristic species groups’with meta-information derived from accompanying studies indicated that the clusters can also be related to habitat conditions.In conclusion,we identified species groups either characteristic of different stages of forest succession after clear-cutting or of impact by fire or a landslide.We expect that the proposed data-mining method will be useful for vegetation classification where no a priori knowledge is available.
文摘Particle swarm optimization(PSO)is one of the popular stochastic optimization based on swarm intelligence algorithm.This simple and promising algorithm has applications in many research fields.In PSO,each particle can adjust its‘flying’according to its own flying experience and its companions’flying experience.This paper proposes a new PSO variant,called the statistically tracked PSO,which uses group statistical characteristics to update the velocity of the particle after certain iterations,thus avoiding localminima and helping particles to explore global optimum with an improved convergence.The performance of the proposed algorithm is tested on a deregulated automatic generation control problem in power systems and encouraging results are obtained.
