Developing Interaction 3D Models for E-Learning Applications

Some issues concerning the development of interactive 3D models for e-learning applications are considered. Given that 3D data sets are normally large and interactive display demands high performance computation, a natural solution would be placing the computational burden on the client machine rather than on the server. Mozilla and Google opted for a combination of client-side languages, JavaScript and OpenGL, to handle 3D graphics in a web browser (Mozilla 3D and O3D respectively). Based on the O3D model, core web technologies are considered and an example of the full process involving the generation of a 3D model and their interactive visualization in a web browser is described. The challenging issue of creating realistic 3D models of objects in the real world is discussed and a method based on line projection for fast 3D reconstruction is presented. The generated model is then visualized in a web browser. The experiments demonstrate that visualization of 3D data in a web browser can provide quality user experience. Moreover, the development of web applications are facilitated by O3D JavaScript extension allowing web designers to focus on 3D contents generation

Novel methods for real-time 3D facial recognition

In this paper we discuss our approach to real-time 3D face recognition. We argue the need for real time operation in a realistic scenario and highlight the required pre- and post-processing operations for effective 3D facial recognition. We focus attention to some operations including face and eye detection, and fast post-processing operations such as hole filling, mesh smoothing and noise removal. We consider strategies for hole filling such as bilinear and polynomial interpolation and Laplace and conclude that bilinear interpolation is preferred. Gaussian and moving average smoothing strategies are compared and it is shown that moving average can have the edge over Gaussian smoothing. The regions around the eyes normally carry a considerable amount of noise and strategies for replacing the eyeball with a spherical surface and the use of an elliptical mask in conjunction with hole filling are compared. Results show that the elliptical mask with hole filling works well on face models and it is simpler to implement. Finally performance issues are considered and the system has demonstrated to be able to perform real-time 3D face recognition in just over 1s 200ms per face model for a small database

Real-time 3D Face Recognition using Line Projection and Mesh Sampling

The main contribution of this paper is to present a novel method for automatic 3D face recognition based on sampling a 3D mesh structure in the presence of noise. A structured light method using line projection is employed where a 3D face is reconstructed from a single 2D shot. The process from image acquisition to recognition is described with focus on its real-time operation. Recognition results are presented and it is demonstrated that it can perform recognition in just over one second per subject in continuous operation mode and thus, suitable for real time operation

Efficient 3D data compression through parameterization of free-form surface patches

This paper presents a new method for 3D data compression based on parameterization of surface patches. The technique is applied to data that can be defined as single valued functions; this is the case for 3D patches obtained using standard 3D scanners. The method defines a number of mesh cutting planes and the intersection of planes on the mesh defines a set of sampling points. These points contain an explicit structure that allows us to define parametrically both x and y coordinates. The z values are interpolated using high degree polynomials and results show that compressions over 99% are achieved while preserving the quality of the mesh

Partial Differential Equations for 3D Data Compression and Reconstruction

This paper describes a PDE-based method for 3D reconstruction of surface patches. The PDE method is exploited using data obtained from standard 3D scanners. First the original surface data are intersected by a number of cutting planes whose intersection points on the mesh are represented by Fourier transforms in each plane. Information on the number of vertices and scale of the surface are defined and, together, these efficiently define the compressed data. The PDE method is then applied at the reconstruction stage by defining PDE surface patches between the cutting planes

Accounting as a tool of state ideology to control captive workers from a House of Correction

The purpose of this paper is to interpret the use of accounting information relating to the House of Correction, a public safety institution established in Rio de Janeiro for the control of workers under a tutelage system (1831-1864). The aim of the House of Correction was to develop a disciplined workforce of former slaves and other "Free Africans". Various control and information procedures were put in place to monitor its achievement of this goal.Design/methodology/approachThis study is based on historical archival research, mainly conducted at the National Archive of Rio de Janeiro and at the Brazilian National Library. The study uses Althusser's ideology concept and the Marxist concept of reproduction of labour to show how accounting information enabled the administrator of the House of Correction to exercise control over the "Free Africans" consistent with the ideologies of the period and place.FindingsThe authors find that the House of Correction pursued a policy of ensuring "Free Africans" were docile, obedient and familiar with State ideology.Originality/valueThis paper extends our knowledge of the use of accounting for the control of workers, who were either captive or repressed due to their ethnical differences; and it shows how ideology can be imposed through the use of accounting information. The authors extend theory by applying the Marxist and Althusserian concept of reproduction of labour to the case of "Free Africans".- This paper was financed by National Funds of the FCT - Portuguese Foundation for Science and Technology within the project "UID/ECO/03182/2019". This work also received funding provided by the CAPES - Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Grant No. BEX 0579/12-2) and by the 2018 Margit F. and Hanns Martin Schoenfeld Scholarship from the Academy of Accounting Historians Section of the American Accounting Association. The authors acknowledge with gratitude the helpful comments of the Accounting, Auditing & Accountability Journal referees and for the constructive comments received from attendees at the ninth Accounting History International Conference, University of Verona, Italy, 6-8 September 2017

A local characterization of quasi-crystal graphs

It is provided a local characterization of quasi-crystal graphs, by presenting a set of local axioms, similar to the ones introduced by Stembridge for crystal graphs of simply-laced root systems. It is also shown that quasi-crystal graphs satisfying these axioms are closed under the tensor product recently introduced by Cain, Guilherme and Malheiro. It is deduced that each connected component of such a graph has a unique highest weight element, whose weight is a composition, and it is isomorphic to a quasi-crystal graph of semistandard quasi-ribbon tableaux

Structure of quasi-crystal graphs and applications to the combinatorics of quasi-symmetric functions

Crystal graphs are powerful combinatorial tools for working with the plactic monoid and symmetric functions. Quasi-crystal graphs are an analogous concept for the hypoplactic monoid and quasi-symmetric functions. This paper makes a combinatorial study of these objects. A previously-observed isomorphism of components of the quasi-crystal graph is explained and explicitly described using a new combinatorial structure called a quasi-array. Then two conjectures of Maas-Gari\'epy on the interaction of fundamental quasi-symmetric functions and Schur functions and on the arrangement of quasi-crystal components within crystal components are settled, the former positively, the latter negatively.Comment: 22 page

Partial differential equations for 3D Data compression and Reconstruction

This paper describes a Partial Differential Equation (PDE) based method for 3D reconstruction of surface patches. The PDE method is exploited using data obtained from standard 3D scanners. First the original surface data are sparsely re-meshed by a number of cutting planes whose intersection points on the mesh are represented by Fourier coefficients in each plane. Information on the number of vertices and scale of the surface are defined and, together, these efficiently define the compressed data. The PDE method is then applied at the reconstruction stage by defining PDE surface patches between the sparse cutting planes recovering thus, the vertex density of the original mesh. Results show that compression rates over 96% are achieved while preserving the quality of the 3D mesh. The paper discusses the suitability of the method to a number of applications and general issues in 3D compression and reconstruction