In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed surfaces.In this paper,we develop a Gregory solid based metho...In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed surfaces.In this paper,we develop a Gregory solid based method to parameterize those models.First,we extend the Gregory patch representation to the trivariate Gregory solid representation.Second,the trivariate Gregory solid representation is employed to interpolate the boundary patches of a geometric model,thus generating the polyhedral volume parametrization.To improve the regularity of the polyhedral volume parametrization,we formulate the construction of the trivariate Gregory solid as a sparse optimization problem,where the optimization objective function is a linear combination of some terms,including a sparse term aiming to reduce the negative Jacobian area of the Gregory solid.Then,the alternating direction method of multipliers(ADMM)is used to solve the sparse optimization problem.Lots of experimental examples illustrated in this paper demonstrate the effectiveness and efficiency of the developed method.展开更多
Gregory Crewdson＇s photography works, full of personal features and American traditional features, exert important effects on contemporary photography, which is worthy of study and use for reference. The photography ...Gregory Crewdson＇s photography works, full of personal features and American traditional features, exert important effects on contemporary photography, which is worthy of study and use for reference. The photography works of Twilight series, the symbol of his creation to maturity, combine realism expression method and surrealism expression method and show the solitude and alienation of humanity in American society, revealing people＇s disassimilation tendency in post-modern society. This paper analyzes the works of Twilight series from the aspects of work creation way, psychological expression, and grotesque.展开更多
Bernard Leake was for many years professor of geology at Glasgow University.In his fine biography–a large and weighty tome–he details the extraordinary career of one of his most notable predecessors,John W.Gregory.P...Bernard Leake was for many years professor of geology at Glasgow University.In his fine biography–a large and weighty tome–he details the extraordinary career of one of his most notable predecessors,John W.Gregory.Perhaps writing the book can be thought of as an act of institutional piety,but one from which we can all benefit:Gregory was a man who inspired;and his light will now shine even more brightly.展开更多
INTRODUCTIONThe mannerisms,appearance and behaviour of the Caesar Julian made him aninviting target for mockery from Constantius’courtiers.It was paft of an effort,soAmmianus maintains,to deny him credit for his succ...INTRODUCTIONThe mannerisms,appearance and behaviour of the Caesar Julian made him aninviting target for mockery from Constantius’courtiers.It was paft of an effort,soAmmianus maintains,to deny him credit for his success in Gaul.His appearancewas likened to that of a hairy goat,or an ape clad in purple.He was like a molethat would not stop talking.His character,too,was attackd:he was supposedlyfearful,pedantic.unworldly.a Doastful exaggerator of his victories.Such展开更多
John A.Gregory,one of the well-known English mathematician in the area of CAD/CAM and Computer Aided Geometric Design,passed away suddenly in March 1993 at the age of 49.The research work and publications of John A.Gr...John A.Gregory,one of the well-known English mathematician in the area of CAD/CAM and Computer Aided Geometric Design,passed away suddenly in March 1993 at the age of 49.The research work and publications of John A.Gregory are summarized in this memorial article.展开更多
基金supported by the National Natural Science Foundation of China(No.61872316)the National Key R&D Program of China(No.2016YFB1001501)the Fundamental Research Funds for the Central Universities(No.2017XZZX009-03)
文摘In isogeometric analysis,it is frequently required to handle the geometric models enclosed by four-sided or non-four-sided boundary patches,such as trimmed surfaces.In this paper,we develop a Gregory solid based method to parameterize those models.First,we extend the Gregory patch representation to the trivariate Gregory solid representation.Second,the trivariate Gregory solid representation is employed to interpolate the boundary patches of a geometric model,thus generating the polyhedral volume parametrization.To improve the regularity of the polyhedral volume parametrization,we formulate the construction of the trivariate Gregory solid as a sparse optimization problem,where the optimization objective function is a linear combination of some terms,including a sparse term aiming to reduce the negative Jacobian area of the Gregory solid.Then,the alternating direction method of multipliers(ADMM)is used to solve the sparse optimization problem.Lots of experimental examples illustrated in this paper demonstrate the effectiveness and efficiency of the developed method.
文摘Gregory Crewdson＇s photography works, full of personal features and American traditional features, exert important effects on contemporary photography, which is worthy of study and use for reference. The photography works of Twilight series, the symbol of his creation to maturity, combine realism expression method and surrealism expression method and show the solitude and alienation of humanity in American society, revealing people＇s disassimilation tendency in post-modern society. This paper analyzes the works of Twilight series from the aspects of work creation way, psychological expression, and grotesque.
文摘Bernard Leake was for many years professor of geology at Glasgow University.In his fine biography–a large and weighty tome–he details the extraordinary career of one of his most notable predecessors,John W.Gregory.Perhaps writing the book can be thought of as an act of institutional piety,but one from which we can all benefit:Gregory was a man who inspired;and his light will now shine even more brightly.
文摘INTRODUCTIONThe mannerisms,appearance and behaviour of the Caesar Julian made him aninviting target for mockery from Constantius’courtiers.It was paft of an effort,soAmmianus maintains,to deny him credit for his success in Gaul.His appearancewas likened to that of a hairy goat,or an ape clad in purple.He was like a molethat would not stop talking.His character,too,was attackd:he was supposedlyfearful,pedantic.unworldly.a Doastful exaggerator of his victories.Such
文摘John A.Gregory,one of the well-known English mathematician in the area of CAD/CAM and Computer Aided Geometric Design,passed away suddenly in March 1993 at the age of 49.The research work and publications of John A.Gregory are summarized in this memorial article.
