Because of poor vocabulary, improper use of lexis, and interference of first language, it is difficult for students in voca-tional school to learn Business English Correspondence well. Business English has close relat...Because of poor vocabulary, improper use of lexis, and interference of first language, it is difficult for students in voca-tional school to learn Business English Correspondence well. Business English has close relations with lexical chunks, whichmakes it necessary to apply lexical approach to teaching of Business English Correspondence. This paper intends to explore its the-oretical foundations and emphasize how to apply lexical approach to teaching of Business English Correspondence in vocationalschool.展开更多
Pragmatic vagueness is frequently used in business correspondences and it offers benefits to the addressers by making business letter more flexible,appropriate and polite.This paper focuses on the employment of vague ...Pragmatic vagueness is frequently used in business correspondences and it offers benefits to the addressers by making business letter more flexible,appropriate and polite.This paper focuses on the employment of vague language in international business correspondences based on the Politeness Principle.In this study,the pragmatic effect of vague language in business correspondence is illustrated and summarized as a motivated factor to better show politeness and respect.The use of vague language motivated by politeness consequently leads to a more smooth,successful and desired communication in business world.展开更多
The Foreign Trade English Correspondence is one of the main courses of International Trade majors.Due to the habit of thinking in Chinese,students usually cannot correctly and flexibly use post-positive attributives i...The Foreign Trade English Correspondence is one of the main courses of International Trade majors.Due to the habit of thinking in Chinese,students usually cannot correctly and flexibly use post-positive attributives in the correspondence writing of foreign trade.Participle phrases,prepositional phrases,attributive clauses,infinitive phrases,adjective phrases and apposition clauses all can follow nouns as post-positive attributives to modify nouns.Mastering the correct expression of post-positive attrib⁃utives will help students improve their writing competence of foreign trade correspondence.展开更多
Breakdown of bulk-boundary correspondence in non-Hermitian(NH)topological systems with generalized inversion symmetries is a controversial issue.The non-Bloch topological invariants determine the existence of edge sta...Breakdown of bulk-boundary correspondence in non-Hermitian(NH)topological systems with generalized inversion symmetries is a controversial issue.The non-Bloch topological invariants determine the existence of edge states,but fail to describe the number and distribution of defective edge states in non-Hermitian topological systems.The state-dependent topological invariants,instead of a global topological invariant,are developed to accurately characterize the bulk-boundary correspondence of the NH systems,which is very different from their Hermitian counterparts.At the same time,we obtain the accurate phase diagram of the one-dimensional non-Hermitian Su–Schrieffer–Heeger model with a generalized inversion symmetry from the state-dependent topological invariants.Therefore,these results will be helpful for understanding the exotic topological properties of various non-Hermitian systems.展开更多
The new classes of Fc-correspondences and Fc -majorised correspondenceswithout open lower sections is introduced. Some existence theorems of madximal elements ofthe Fc -correspondences and the Fc-majorized corresponde...The new classes of Fc-correspondences and Fc -majorised correspondenceswithout open lower sections is introduced. Some existence theorems of madximal elements ofthe Fc -correspondences and the Fc-majorized correspondences defined on noncompactset in topological vector spaces are obtained. As applications, some existence theoremsof equilibrium points for one-person games, qualitative games and generalized games withthe Fc -majorized correspondences devined on noncompact strategy sets in topologicalvector spaces are also given. These theorems improve and generalize several known resultsin recent literature.展开更多
In the paper,we define weakly δ-continuous correspondences on super-space,On the basis of δ-open(closed) sets,θ-open(closed) sets and regular open(closed) sets in topological space,some equivalent conditions of thi...In the paper,we define weakly δ-continuous correspondences on super-space,On the basis of δ-open(closed) sets,θ-open(closed) sets and regular open(closed) sets in topological space,some equivalent conditions of this kind of correspondences are obtained,and some applications of subset nets and convergence nets are given.展开更多
This paper is an attempt to analyse the role of negative transfer in the acquisition of business English correspondence through the analysis of errors made in learners’writings.The analysis is focused on errors made ...This paper is an attempt to analyse the role of negative transfer in the acquisition of business English correspondence through the analysis of errors made in learners’writings.The analysis is focused on errors made violating clarity.Through the contrast between those errors and the normative samples,one of the deep-rooted reasons that prohibits learners to make the correspondences be clarified are discovered,which is the negative transfer resulted from different thought patterns affected by the cultural diversities.展开更多
Floquet engineering appears as a new protocol for designing topological states of matter,and features anomalous edge modes pinned at quasi-energy π/T with vanished topological index.We propose how to predict the anom...Floquet engineering appears as a new protocol for designing topological states of matter,and features anomalous edge modes pinned at quasi-energy π/T with vanished topological index.We propose how to predict the anomalous edge modes via the bulk Hamiltonian in frequency space,and use Zak phase to quantitatively index the topological properties.The above methods are clarified by the example of time periodic Kitaev chain with chemical potential of harmonic driving and pulse driving,and topological phase transitions are manifested at different driving frequencies.展开更多
The thermal response of static monopole particle detector in the presence of boundaries are given.We put forward a weak correspondence principle between Rindler response and thermal response and illustrate it in a num...The thermal response of static monopole particle detector in the presence of boundaries are given.We put forward a weak correspondence principle between Rindler response and thermal response and illustrate it in a number of examples.展开更多
We investigate novel features of three-dimensional non-Hermitian Weyl semimetals,paying special attention to the unconventional bulk-boundary correspondence.We use the non-Bloch Chern numbers as the tool to obtain the...We investigate novel features of three-dimensional non-Hermitian Weyl semimetals,paying special attention to the unconventional bulk-boundary correspondence.We use the non-Bloch Chern numbers as the tool to obtain the topological phase diagram,which is also confirmed by the energy spectra from our numerical results.It is shown that,in sharp contrast to Hermitian systems,the conventional(Bloch)bulk-boundary correspondence breaks down in non-Hermitian topological semimetals,which is caused by the non-Hermitian skin effect.We establish the non-Bloch bulk-boundary correspondence for non-Hermitian Weyl semimetals:the topological edge modes are determined by the non-Bloch Chern number of the bulk bands.Moreover,these topological edge modes can manifest as the unidirectional edge motion,and their signatures are consistent with the non-Bloch bulk-boundary correspondence.Our work establishes the non-Bloch bulk-boundary correspondence for non-Hermitian topological semimetals.展开更多
The interference order structure in the angular spectrum is demonstrated for the sea acoustical waveguide.The one-to-one correspondence between the modes and the orders of interference is proved.
Based on the theory of integration within s-ordering of operators and the bipartite entangled state representation we introduce s-parameterized Weyl-Wigner correspondence in the entangled form. Some of its application...Based on the theory of integration within s-ordering of operators and the bipartite entangled state representation we introduce s-parameterized Weyl-Wigner correspondence in the entangled form. Some of its applications in quantum optics theory are presented as well.展开更多
Statistics of this Paper derive from a business correspondence translation,Sing Sing Lounge,participated by English ma jors of one higher-educational institution.Facilitated with means of quantitative approach,this Pa...Statistics of this Paper derive from a business correspondence translation,Sing Sing Lounge,participated by English ma jors of one higher-educational institution.Facilitated with means of quantitative approach,this Paper,introducing an applicable procedure to analyze translation by students from one Class,is devoted to discover subjects used in declarative sentences of their translations.展开更多
Nowadays, with the background of economic globalization, shopping modes like e Bay, Ali Express and Amazon are popular among the public. Business English that plays an increasingly important role in international trad...Nowadays, with the background of economic globalization, shopping modes like e Bay, Ali Express and Amazon are popular among the public. Business English that plays an increasingly important role in international trades is widely applied to commercial activities. However, because of insufficient practical experience, improper use of stylistics and interference of first language, sometimes it is difficult for students in school to have good command of business English correspondence. This dissertation has suggested learners several ways to improve their competence in international communications and the teaching and learning efficiency, by analyzing the stylistic features of business English correspondences and the problems collecting from the learners on the basis of the data of questionnaires.展开更多
We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by t...We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.展开更多
Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses （DCCAs） and a two-way indicator species analysis （TWINSPAN）. The distributi...Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses （DCCAs） and a two-way indicator species analysis （TWINSPAN）. The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.展开更多
An approach to addressing the stereo correspondence problem is presented using genetic algorithms (GAs) to obtain a dense disparity map. Different from previous methods, this approach casts the stereo matching as a mu...An approach to addressing the stereo correspondence problem is presented using genetic algorithms (GAs) to obtain a dense disparity map. Different from previous methods, this approach casts the stereo matching as a multi-extrema optimization problem such that finding the fittest solution from a set of potential disparity maps. Among a wide variety of optimization techniques, GAs are proven to be potentially effective methods for the global optimization problems with large search space. With this idea, each disparity map is viewed as an individual and the disparity values are encoded as chromosomes, so each individual has lots of chromosomes in the approach. Then, several matching constraints are formulated into an objective function, and GAs are used to search the global optimal solution for the problem. Furthermore, the coarse-to-fine strategy has been embedded in the approach so as to reduce the matching ambiguity and the time consumption. Finally, experimental results on synthetic and real images show the performance of the work.展开更多
We report the nonlocal imaging of an object by conditional averaging of the random exposure frames of a reference detector,which only sees the freely propagating field from a thermal light source.A bucket detector,syn...We report the nonlocal imaging of an object by conditional averaging of the random exposure frames of a reference detector,which only sees the freely propagating field from a thermal light source.A bucket detector,synchronized with the reference detector,records the intensity fluctuations of an identical beam passing through the object mask.These fluctuations are sorted according to their values relative to the mean,then the reference data in the corresponding time-bins for a given fluctuation range are averaged,to produce either positive or negative images.Since no correlation calculations are involved,this correspondence imaging technique challenges our former interpretations of “ghost” imaging.Compared with conventional correlation imaging or compressed sensing schemes,both the number of exposures and computation time are greatly reduced,while the visibility is much improved.A simple statistical model is presented to explain the phenomenon.展开更多
Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspon-dence analyses(DCCAs) and a two-way indicator species analysis(TWINSPAN).The distribution pat...Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspon-dence analyses(DCCAs) and a two-way indicator species analysis(TWINSPAN).The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods.Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis.The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium.Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation.Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively.Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.展开更多
This paper proposes a simple geometrical ray based approach to solve the stereo correspondence problem for the single-lens bi-prism stereovision system. Each image captured using this system can be divided into two su...This paper proposes a simple geometrical ray based approach to solve the stereo correspondence problem for the single-lens bi-prism stereovision system. Each image captured using this system can be divided into two sub-images on the left and right and these sub-images are generated by two virtual cameras which are produced by the bi-prism. This stereovision system is equivalent to the conventional two camera system and the two sub-images captured have disparities which can be used to reconstruct back the 3-dimensional （3D） scene. The stereo correspondence problem of this system will be solved geometrically by applying the epipolar geometry constraint on the generated virtual cameras instead of the real CCD camera. Experiments are conducted to validate the proposed method and the results are compared to the calibration based approach to confirm its accuracy and effectiveness.展开更多
文摘Because of poor vocabulary, improper use of lexis, and interference of first language, it is difficult for students in voca-tional school to learn Business English Correspondence well. Business English has close relations with lexical chunks, whichmakes it necessary to apply lexical approach to teaching of Business English Correspondence. This paper intends to explore its the-oretical foundations and emphasize how to apply lexical approach to teaching of Business English Correspondence in vocationalschool.
文摘Pragmatic vagueness is frequently used in business correspondences and it offers benefits to the addressers by making business letter more flexible,appropriate and polite.This paper focuses on the employment of vague language in international business correspondences based on the Politeness Principle.In this study,the pragmatic effect of vague language in business correspondence is illustrated and summarized as a motivated factor to better show politeness and respect.The use of vague language motivated by politeness consequently leads to a more smooth,successful and desired communication in business world.
文摘The Foreign Trade English Correspondence is one of the main courses of International Trade majors.Due to the habit of thinking in Chinese,students usually cannot correctly and flexibly use post-positive attributives in the correspondence writing of foreign trade.Participle phrases,prepositional phrases,attributive clauses,infinitive phrases,adjective phrases and apposition clauses all can follow nouns as post-positive attributives to modify nouns.Mastering the correct expression of post-positive attrib⁃utives will help students improve their writing competence of foreign trade correspondence.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11674026 and 11974053)。
文摘Breakdown of bulk-boundary correspondence in non-Hermitian(NH)topological systems with generalized inversion symmetries is a controversial issue.The non-Bloch topological invariants determine the existence of edge states,but fail to describe the number and distribution of defective edge states in non-Hermitian topological systems.The state-dependent topological invariants,instead of a global topological invariant,are developed to accurately characterize the bulk-boundary correspondence of the NH systems,which is very different from their Hermitian counterparts.At the same time,we obtain the accurate phase diagram of the one-dimensional non-Hermitian Su–Schrieffer–Heeger model with a generalized inversion symmetry from the state-dependent topological invariants.Therefore,these results will be helpful for understanding the exotic topological properties of various non-Hermitian systems.
文摘The new classes of Fc-correspondences and Fc -majorised correspondenceswithout open lower sections is introduced. Some existence theorems of madximal elements ofthe Fc -correspondences and the Fc-majorized correspondences defined on noncompactset in topological vector spaces are obtained. As applications, some existence theoremsof equilibrium points for one-person games, qualitative games and generalized games withthe Fc -majorized correspondences devined on noncompact strategy sets in topologicalvector spaces are also given. These theorems improve and generalize several known resultsin recent literature.
文摘In the paper,we define weakly δ-continuous correspondences on super-space,On the basis of δ-open(closed) sets,θ-open(closed) sets and regular open(closed) sets in topological space,some equivalent conditions of this kind of correspondences are obtained,and some applications of subset nets and convergence nets are given.
文摘This paper is an attempt to analyse the role of negative transfer in the acquisition of business English correspondence through the analysis of errors made in learners’writings.The analysis is focused on errors made violating clarity.Through the contrast between those errors and the normative samples,one of the deep-rooted reasons that prohibits learners to make the correspondences be clarified are discovered,which is the negative transfer resulted from different thought patterns affected by the cultural diversities.
基金Project supported by the National Natural Science Foundation of China(Grant No.2016YFA0301500)。
文摘Floquet engineering appears as a new protocol for designing topological states of matter,and features anomalous edge modes pinned at quasi-energy π/T with vanished topological index.We propose how to predict the anomalous edge modes via the bulk Hamiltonian in frequency space,and use Zak phase to quantitatively index the topological properties.The above methods are clarified by the example of time periodic Kitaev chain with chemical potential of harmonic driving and pulse driving,and topological phase transitions are manifested at different driving frequencies.
文摘The thermal response of static monopole particle detector in the presence of boundaries are given.We put forward a weak correspondence principle between Rindler response and thermal response and illustrate it in a number of examples.
基金the National Natural Science Foundation of China(Grants No.11504143).
文摘We investigate novel features of three-dimensional non-Hermitian Weyl semimetals,paying special attention to the unconventional bulk-boundary correspondence.We use the non-Bloch Chern numbers as the tool to obtain the topological phase diagram,which is also confirmed by the energy spectra from our numerical results.It is shown that,in sharp contrast to Hermitian systems,the conventional(Bloch)bulk-boundary correspondence breaks down in non-Hermitian topological semimetals,which is caused by the non-Hermitian skin effect.We establish the non-Bloch bulk-boundary correspondence for non-Hermitian Weyl semimetals:the topological edge modes are determined by the non-Bloch Chern number of the bulk bands.Moreover,these topological edge modes can manifest as the unidirectional edge motion,and their signatures are consistent with the non-Bloch bulk-boundary correspondence.Our work establishes the non-Bloch bulk-boundary correspondence for non-Hermitian topological semimetals.
文摘The interference order structure in the angular spectrum is demonstrated for the sea acoustical waveguide.The one-to-one correspondence between the modes and the orders of interference is proved.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10775097 and 10874174)the President Foundation of the Chinese Academy of Sciences
文摘Based on the theory of integration within s-ordering of operators and the bipartite entangled state representation we introduce s-parameterized Weyl-Wigner correspondence in the entangled form. Some of its applications in quantum optics theory are presented as well.
文摘Statistics of this Paper derive from a business correspondence translation,Sing Sing Lounge,participated by English ma jors of one higher-educational institution.Facilitated with means of quantitative approach,this Paper,introducing an applicable procedure to analyze translation by students from one Class,is devoted to discover subjects used in declarative sentences of their translations.
文摘Nowadays, with the background of economic globalization, shopping modes like e Bay, Ali Express and Amazon are popular among the public. Business English that plays an increasingly important role in international trades is widely applied to commercial activities. However, because of insufficient practical experience, improper use of stylistics and interference of first language, sometimes it is difficult for students in school to have good command of business English correspondence. This dissertation has suggested learners several ways to improve their competence in international communications and the teaching and learning efficiency, by analyzing the stylistic features of business English correspondences and the problems collecting from the learners on the basis of the data of questionnaires.
基金supported by the Natural Science Foundation of Zhejiang Province,China (Grant Nos.LR22A040001 and LY21A040004)the National Natural Science Foundation of China (Grant Nos.12074342 and 11835011)。
文摘We investigate the topological properties of a two-chain quantum ladder with uneven legs,i.e.,the two chains differ in their periods by a factor of 2.Such an uneven ladder presents rich band structures classified by the closure of either direct or indirect bandgaps.It also provides opportunities to explore fundamental concepts concerning band topology and edge modes,including the difference of intracellular and intercellular Zak phases,and the role of the inversion symmetry(IS).We calculate the Zak phases of the two kinds and find excellent agreement with the dipole moment and extra charge accumulation.We also find that configurations with IS feature a pair of degenerate two-side edge modes emerging as the closure of the direct bandgap,while configurations without IS feature one-side edge modes emerging as not only the closure of both direct and indirect bandgaps but also within the band continuum.Furthermore,by projecting to the two sublattices,we find that the effective Bloch Hamiltonian corresponds to that of a generalized Su–Schrieffer–Heeger model or the Rice–Mele model whose hopping amplitudes depend on the quasimomentum.In this way,the topological phases can be efficiently extracted through winding numbers.We propose that uneven ladders can be realized by spin-dependent optical lattices and their rich topological characteristics can be examined by near future experiments.
基金Foundation project： This study was financially supported by the Na- tional Natural Science Foundation of China （No. 40771172） and the orientation project of the Chinese Academy of Sciences （No. kzcx2-yw-308）
文摘Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses （DCCAs） and a two-way indicator species analysis （TWINSPAN）. The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.
文摘An approach to addressing the stereo correspondence problem is presented using genetic algorithms (GAs) to obtain a dense disparity map. Different from previous methods, this approach casts the stereo matching as a multi-extrema optimization problem such that finding the fittest solution from a set of potential disparity maps. Among a wide variety of optimization techniques, GAs are proven to be potentially effective methods for the global optimization problems with large search space. With this idea, each disparity map is viewed as an individual and the disparity values are encoded as chromosomes, so each individual has lots of chromosomes in the approach. Then, several matching constraints are formulated into an objective function, and GAs are used to search the global optimal solution for the problem. Furthermore, the coarse-to-fine strategy has been embedded in the approach so as to reduce the matching ambiguity and the time consumption. Finally, experimental results on synthetic and real images show the performance of the work.
基金Supported by the National Natural Science Foundation of China under Grant No 60978002the National Basic Research Program of China under Grant Nos 2010CB922904 and 2007CB814800the National High Technology R&D Program of China under Grant No 2011AA120102。
文摘We report the nonlocal imaging of an object by conditional averaging of the random exposure frames of a reference detector,which only sees the freely propagating field from a thermal light source.A bucket detector,synchronized with the reference detector,records the intensity fluctuations of an identical beam passing through the object mask.These fluctuations are sorted according to their values relative to the mean,then the reference data in the corresponding time-bins for a given fluctuation range are averaged,to produce either positive or negative images.Since no correlation calculations are involved,this correspondence imaging technique challenges our former interpretations of “ghost” imaging.Compared with conventional correlation imaging or compressed sensing schemes,both the number of exposures and computation time are greatly reduced,while the visibility is much improved.A simple statistical model is presented to explain the phenomenon.
基金supported by the Na-tional Natural Science Foundation of China (No. 40771172)the orientation project of the Chinese Academy of Sciences (No. kzcx2-yw-308)
文摘Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspon-dence analyses(DCCAs) and a two-way indicator species analysis(TWINSPAN).The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods.Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis.The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium.Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation.Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively.Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.
文摘This paper proposes a simple geometrical ray based approach to solve the stereo correspondence problem for the single-lens bi-prism stereovision system. Each image captured using this system can be divided into two sub-images on the left and right and these sub-images are generated by two virtual cameras which are produced by the bi-prism. This stereovision system is equivalent to the conventional two camera system and the two sub-images captured have disparities which can be used to reconstruct back the 3-dimensional （3D） scene. The stereo correspondence problem of this system will be solved geometrically by applying the epipolar geometry constraint on the generated virtual cameras instead of the real CCD camera. Experiments are conducted to validate the proposed method and the results are compared to the calibration based approach to confirm its accuracy and effectiveness.
