Search results for "Dimension"
showing 10 items of 2766 documents
Commutators and diffeomorphisms of surfaces
2004
For any compact oriented surfacewe consider the group of diffeomorphisms ofwhich preserve a given area form. In this paper we show that the vector space of homogeneous quasi-morphisms on this group has infinite dimension. This result is proved by constructing explicitly and for each surface an infinite family of independent homogeneous quasi-morphisms. These constructions use simple arguments related to linking properties of the orbits of the diffeomorphisms.
Facial scanning accuracy depending on the alignment algorithm and digitized surface area location: An in vitro study.
2021
To measure the accuracy (trueness and precision) of a facial scanner depending on the alignment method and the digitized surface area location.Fourteen markers were adhered on a head mannequin and digitized using an industrial scanner (GOM Atos Q 3D 12 M; Carl Zeiss Industrielle Messtechnik GmbH). A control mesh was acquired. Subsequently, the mannequin was digitized using a facial scanner (Arc4; Bellus3D) (n = 30). The control mesh was delineated into 10 areas. Based on the alignment procedures, two groups were created: reference best fit (RBF group) and landmark-based best fit (LA group). The root mean square was used to calculate the discrepancy between the control mesh and each facial s…
An Automatic Three-Dimensional Fuzzy Edge Detector
2009
Three-dimensional object analysis is of particular interest in many research fields. In this context, the most common data representation is boundary mesh, namely, 2D surface embedded in 3D space. We will investigate the problem of 3D edge extraction, that is, salient surface regions characterized by high flexure. Our automatic edge detection method assigns a value, proportional to the local bending of the surface, to the elements of the mesh. Moreover, a proper scanning window, centered on each element, is used to discriminate between smooth zones of the surface and its edges. The algorithm does not require input parameters and returns a set of elements that represent the salient features …
Application of fractal geometry to dissolution kinetic study of a sweetener excipient
2001
Abstract In the context of relationship study between dissolution kinetic and particle morphology using the fractal geometry tool, we use a commercially available quality of saccharin powder. The characterization of molecular feature and image analysis study allows us to conclude to the statistic self-similarity of particles of four sieved particles size fractions, permitting the fractal approach. Calculation of reactive fractal dimension is performed using two forms of mass transfer equation: −d Q /d t = kQ D R /3 Δ C and −d Q /d t = k′R D R −3 Δ C , with Δ C ={ C f /[ln C s /( C s − C f )]}. Based on comparison of the surface fractal dimension D S on the two values of reactive fractal di…
Boolean operations with implicit and parametric representation of primitives using R-functions
2005
We present a new and efficient algorithm to accurately polygonize an implicit surface generated by multiple Boolean operations with globally deformed primitives. Our algorithm is special in the sense that it can be applied to objects with both an implicit and a parametric representation, such as superquadrics, supershapes, and Dupin cyclides. The input is a constructive solid geometry tree (CSG tree) that contains the Boolean operations, the parameters of the primitives, and the global deformations. At each node of the CSG tree, the implicit formulations of the subtrees are used to quickly determine the parts to be transmitted to the parent node, while the primitives' parametric definition …
Printing Life-Inspired Subcellular Scale Compartments with Autonomous Molecularly Crowded Confinement.
2019
A simple, rapid, and highly controlled platform to prepare life-inspired subcellular scale compartments by inkjet printing has been developed. These compartments consist of fL-scale aqueous droplets (few µm in diameter) incorporating biologically relevant molecular entities with programmed composition and concentration. These droplets are ink-jetted in nL mineral oil drop arrays allowing for lab-on-chip studies by fluorescence microscopy and fluorescence life time imaging. Once formed, fL-droplets are stable for several hours, thus giving the possibility of readily analyze molecular reactions and their kinetics and to verify molecular behavior and intermolecular interactions. Here, this pla…
What does preoperative three-dimensional image contribute to complex pancreatic surgery?
2020
Abstract The possibility of modelling diagnostic images in three dimensions (3D) in pancreatic surgery is a novelty that provides us multiple advantages. A better visualization of the structures allows us a more accurate planning of the surgical technique and makes it easier the surgery in complex cases. We present the case study of a borderline pancreatic head adenocarcinoma patient to illustrate the advantages of 3D modelling in complex pancreatic surgery. The help of 3D technology allowed us to optimally plan the intervention and facilitate surgical resection. The use of this tool could translate into: shorter operative time, fewer intraoperative complications or an increase in R0 resect…
The effect of detergents on the basement membrane complex of a biologic scaffold material
2013
The basement membrane complex (BMC) is a critical component of the extracellular matrix (ECM) that supports and facilitates the growth of cells. This study investigates four detergents commonly used in the process of tissue decellularization and their effect upon the BMC. The BMC of porcine urinary bladder was subjected to 3% Triton-X 100, 8 mM 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), 4% sodium deoxycholate or 1% sodium dodecyl sulfate (SDS) for 24 h. The BMC structure for each treatment group was assessed by immunolabeling, scanning electron microscopy (SEM) and second harmonic generation (SHG) imaging of the fiber network. The composition was assessed by quantif…
Sustainable tourism: Measures, evidence and future prospects.
2021
The Chapter aims to provide a critical review of the quantitative approaches so far introduced in literature to measure the sustainable tourism. We focus on both variables and methods employed to obtain synthetic indicators of sustainable tourism and aim to provide some critical insights on potential new challenges caused by the current pandemic. For example, some dimensions of tourism sustainability may become more relevant in future due to the increasing attention by people on health and safety. Finally, a focus on the studies on measurement of sustainable tourism in the Mediterranean area will be provided.
Survey-based qualitative analysis of young generation perception of sustainable development in Poland
2020
Abstract Understanding the perception of Sustainable Development can help to identify misconceptions surrounding the concept in order to design better education plans and public policies on this subject. Evaluating the perception of sustainability issues by focusing on the young generation as is an important proxy to imagine what the future holds for in terms of addressing sustainable development. We conducted 177 in-person interviews on a heterogeneous group of students and random volunteers in four cities in Poland to assess their perception of Sustainable Development. The vast majority (89.3%) of the respondents were familiar with the term ‘Sustainable Development’. However, part of them…