The problem of spherical parametrization is that of mapping a genus-zero mesh onto a spherical surface. For a given mesh, different parametrizations can be obtained by different methods. And for a certain application,...The problem of spherical parametrization is that of mapping a genus-zero mesh onto a spherical surface. For a given mesh, different parametrizations can be obtained by different methods. And for a certain application, some parametrization results might behave better than others. In this paper, we will propose a method to parametrize a genus-zero mesh so that a surface fitting algorithm with PHT-splines can generate good result. Here the parametrization results are obtained by minimizing discrete har- monic energy subject to spherical constraints. Then some applications are given to illustrate the advantages of our results. Based on PHT-splines, parametric surfaces can be constructed efficiently and adaptively to fit genus-zero meshes after their spherical parametrization has been obtained.展开更多
The idempotent semirings Rmax and Rmin play a crucial role in several areas of mathematics and their applications such as discrete mathematics, algebraic geometry, computer science, computer languages, linguistic prob...The idempotent semirings Rmax and Rmin play a crucial role in several areas of mathematics and their applications such as discrete mathematics, algebraic geometry, computer science, computer languages, linguistic problems, optimization theory, discrete event systems, fuzzy logics. In this paper we consider the expansion of the semirings Rmax and Rmin with residuals and describe how to use these expended semirings in public key cryptography.展开更多
Based on elliptic curve Diffie-Hellman algorithm, an Elliptic Curve Authenticated Key Agreement (ECAKA) protocol with pre-shared password is proposed. Its security relies on the Elliptic Curve Discrete Logarithm Probl...Based on elliptic curve Diffie-Hellman algorithm, an Elliptic Curve Authenticated Key Agreement (ECAKA) protocol with pre-shared password is proposed. Its security relies on the Elliptic Curve Discrete Logarithm Problem (ECDLP). It provides identity authentication, key validation and perfect forward secrecy, and it can foil man-in-the-middle attacks.展开更多
The paper explores the relationships between the largest cardinality of a semi antichain and the smallest cardinality of its unichain covering on the direct product space induced by two partially ordered sets,through ...The paper explores the relationships between the largest cardinality of a semi antichain and the smallest cardinality of its unichain covering on the direct product space induced by two partially ordered sets,through studying on partially ordered sets. A sufficient condition under which they are equal is obtained.展开更多
There are philosophers and logicians who do think that the Trinity-triangle makes up an evident formal-logic inconsistency demonstrating convincingly that Christian faith is illogical and hence irrational one. The pre...There are philosophers and logicians who do think that the Trinity-triangle makes up an evident formal-logic inconsistency demonstrating convincingly that Christian faith is illogical and hence irrational one. The present paper submits a systematic counter-argumentation against such thinking. According to the submitted counter-arguments, there is no formal-logic inconsistency in the Holy-Trinity-triangle： There is only a logic-linguistic illusion of such inconsistency which illusion is naturally produced by the ambiguity of the word ＂is＂ in natural language. The author has invented an effective remedy for that illusion, namely, a precise formulation of the generalized and thus modernized Guillotine of Hume by means of an artificial language of two-valued algebraic system of formal ethics of moral rigor. Systematical using the mathematized formulation of the generalized Hume＇s Guillotine cuts down the mentioned linguistic illusion of logical inconsistency. Thus, the paper essentially interconnects discrete mathematical representations of formal iogic of thinking and formal ethics of acting. In relation to contemporary symbolic logic, the author submits not a technical result solving some important particular problem concerning some specific system of symbolic logic but a significantly new result of conceptual work concerning logic in general and its interconnection with mathematical ethics. The old idea of logic as a moral science is transformed into a novel idea of symbolic logic as a brunch of mathematical ethics. In particular, two-valued algebra of classical formal logic is considered as a particular case of two-valued algebra of formal ethics of moral rigor. The submitted conception of logic is instantiated by applying it to the knotty logic-problem of Holy-Trinity-triangle.展开更多
A method of 3D model reconstruction based on scattered point data in reverse engineering is presented here. The topological relationship of scattered points was established firstly, then the data set was triangulated ...A method of 3D model reconstruction based on scattered point data in reverse engineering is presented here. The topological relationship of scattered points was established firstly, then the data set was triangulated to reconstruct the mesh surface model. The curvatures of cloud data were calculated based on the mesh surface, and the point data were segmented by edge-based method; Every patch of data was fitted by quadric surface of freeform surface, and the type of quadric surface was decided by parameters automatically, at last the whole CAD model was created. An example of mouse model was employed to confirm the effect of the algorithm.展开更多
基金Project supported by the Outstanding Youth Grant of Natural Science Foundation of China (No. 60225002), the National Basic Research Program (973) of China (No. 2004CB318000), the National Natural Science Foundation of China (Nos. 60533060 and 60473132)
文摘The problem of spherical parametrization is that of mapping a genus-zero mesh onto a spherical surface. For a given mesh, different parametrizations can be obtained by different methods. And for a certain application, some parametrization results might behave better than others. In this paper, we will propose a method to parametrize a genus-zero mesh so that a surface fitting algorithm with PHT-splines can generate good result. Here the parametrization results are obtained by minimizing discrete har- monic energy subject to spherical constraints. Then some applications are given to illustrate the advantages of our results. Based on PHT-splines, parametric surfaces can be constructed efficiently and adaptively to fit genus-zero meshes after their spherical parametrization has been obtained.
文摘The idempotent semirings Rmax and Rmin play a crucial role in several areas of mathematics and their applications such as discrete mathematics, algebraic geometry, computer science, computer languages, linguistic problems, optimization theory, discrete event systems, fuzzy logics. In this paper we consider the expansion of the semirings Rmax and Rmin with residuals and describe how to use these expended semirings in public key cryptography.
基金Supported by "973" Program of China (No.G1999035805), "863" Program of China(No.2002AA143041), and RGC Project (No.HKU/7144/03E) of the Hong Kong SpecialAdministrative Region, China.
文摘Based on elliptic curve Diffie-Hellman algorithm, an Elliptic Curve Authenticated Key Agreement (ECAKA) protocol with pre-shared password is proposed. Its security relies on the Elliptic Curve Discrete Logarithm Problem (ECDLP). It provides identity authentication, key validation and perfect forward secrecy, and it can foil man-in-the-middle attacks.
文摘The paper explores the relationships between the largest cardinality of a semi antichain and the smallest cardinality of its unichain covering on the direct product space induced by two partially ordered sets,through studying on partially ordered sets. A sufficient condition under which they are equal is obtained.
文摘There are philosophers and logicians who do think that the Trinity-triangle makes up an evident formal-logic inconsistency demonstrating convincingly that Christian faith is illogical and hence irrational one. The present paper submits a systematic counter-argumentation against such thinking. According to the submitted counter-arguments, there is no formal-logic inconsistency in the Holy-Trinity-triangle： There is only a logic-linguistic illusion of such inconsistency which illusion is naturally produced by the ambiguity of the word ＂is＂ in natural language. The author has invented an effective remedy for that illusion, namely, a precise formulation of the generalized and thus modernized Guillotine of Hume by means of an artificial language of two-valued algebraic system of formal ethics of moral rigor. Systematical using the mathematized formulation of the generalized Hume＇s Guillotine cuts down the mentioned linguistic illusion of logical inconsistency. Thus, the paper essentially interconnects discrete mathematical representations of formal iogic of thinking and formal ethics of acting. In relation to contemporary symbolic logic, the author submits not a technical result solving some important particular problem concerning some specific system of symbolic logic but a significantly new result of conceptual work concerning logic in general and its interconnection with mathematical ethics. The old idea of logic as a moral science is transformed into a novel idea of symbolic logic as a brunch of mathematical ethics. In particular, two-valued algebra of classical formal logic is considered as a particular case of two-valued algebra of formal ethics of moral rigor. The submitted conception of logic is instantiated by applying it to the knotty logic-problem of Holy-Trinity-triangle.
文摘A method of 3D model reconstruction based on scattered point data in reverse engineering is presented here. The topological relationship of scattered points was established firstly, then the data set was triangulated to reconstruct the mesh surface model. The curvatures of cloud data were calculated based on the mesh surface, and the point data were segmented by edge-based method; Every patch of data was fitted by quadric surface of freeform surface, and the type of quadric surface was decided by parameters automatically, at last the whole CAD model was created. An example of mouse model was employed to confirm the effect of the algorithm.
