A numerical algorithm for solving the three-dimensional Stefan problem in spatial coordinates fixed to the solution

1989 ◽  
Vol 45 (4) ◽  
pp. 1321-1324
Author(s):  
V. D. Glushenkov
Keyword(s):  
Stefan Problem ◽  
Numerical Algorithm ◽  
Three Dimensional ◽  
Spatial Coordinates

Impact of the global outflow angle on recanalization after endovascular treatment of middle cerebral artery bifurcation aneurysms

2018 ◽  
Vol 10 (12) ◽  
pp. 1174-1178 ◽  
Author(s):  
Yannick de La Torre ◽  
Stéphane Velasco ◽  
Jean-Pierre Tasu ◽  
Cassandre Wanpouille ◽  
Paul Chan ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Predictive Factors ◽  
Univariate Analysis ◽  
Three Dimensional ◽  
Flow Angle ◽  
Neck Size ◽  
Spatial Coordinates ◽  
Independent Risk Factors

Background and purposeIntracranial aneurysm recanalization after endovascular treatment (EVT) remains a major problem. The goal of this study was to find new predictive factors of recanalization after EVT of middle cerebral artery (MCA) bifurcation aneurysms.Methods96 MCA bifurcationaneurysms, ruptured or unruptured, treated by EVT between Septembre 2009 and December 2014, were retrospectively included. Clinical parameters and aneurysm characteristics were recorded. From the initial three-dimensional DSA, spatial coordinates found on parent and daughter arteries of MCA bifurcations gave four different flow angle values; inflow, outflows 1 and 2, and the global outflow angle (the sum of the two outflow angles). Inter- and intra-observer reproducibilities of three-dimensional angle value measurements were performed.ResultsRecanalization occurred in 25 cases (26%) and retreatment was performed in 11 cases (11%). Only 1 patient (1%) had rebleeding. Univariate analysis established the following as predictive factors of recanalization: high blood pressure (P=0.014), aneurysm height (P<0.001), aneurysm width (P<0.001), neck size (P<0.001), postoperative occlusion class (P=0.040), percentage of packing volume (P<0.001), as well as the two outflow angles (P=0.006 and 0.045), and the global outflow angle (P<0.001). Multivariate analysis revealed two independent risk factors for recanalization: the global outflow angle (OR=1.05; 95% CI 1.02 to 1.08; P<0.002) and aneurysm width (OR=0.67; 95% CI 0.46 to 0.96; P=0.031). A global outflow angle threshold <192° was found to be a risk factor for recanalization (OR=13.75; 95% CI 4.46 to 42.44), with a sensitivity of 80% and specificity of 77%.ConclusionsThis study emphasizes that a new parameter, the global outflow angle, can be predictive of recanalization for MCA bifurcation aneurysms treated by EVT.

Mining in Spatio-Temporal Databases

2011 ◽  
pp. 272-293
Author(s):  
Junmei Wang ◽  
Wynne Hsu ◽  
Mong Li Lee
Keyword(s):  
Spatial Databases ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Temporal Databases ◽  
Temporal Data ◽  
Service Patterns ◽  
Sequence Patterns ◽  
Spatial Coordinates ◽  
Spatio Temporal ◽  
Work Done

Recent interest in spatio-temporal applications has been fueled by the need to discover and predict complex patterns that occur when we observe the behavior of objects in the three-dimensional space of time and spatial coordinates. Although the complex and intrinsic relationships among the spatio-temporal data limit the usefulness of conventional data mining techniques to discover the patterns in the spatio-temporal databases, they also lead to opportunities for mining new classes of patterns in spatio-temporal databases. This chapter provides a survey of the work done for mining patterns in spatial databases and temporal databases, and the preliminary work for mining patterns in spatio-temporal databases. We highlight the unique challenges of mining interesting patterns in spatio-temporal databases. We also describe two special types of spatio-temporal patterns: location-sensitive sequence patterns and geographical features for location-based service patterns.

scholarly journals Accuracy Assessment for the Three-Dimensional Coordinates by High-Speed Videogrammetric Measurement

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Xianglei Liu ◽  
Yi Tang ◽  
Jing Ma
Keyword(s):  
High Speed ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Shaking Table ◽  
Measuring System ◽  
Accuracy Analysis ◽  
Alternative Technique ◽  
Cmos Camera ◽  
Spatial Coordinates ◽  
Three Dimensional Coordinate

High-speed CMOS camera is a new kind of transducer to make the videogrammetric measurement for monitoring the displacement of high-speed shaking table structure. The purpose of this paper is to validate the three-dimensional coordinate accuracy of the shaking table structure acquired from the presented high-speed videogrammetric measuring system. In the paper, all of the key intermediate links are discussed, including the high-speed CMOS videogrammetric measurement system, the layout of the control network, the elliptical target detection, and the accuracy validation of final 3D spatial results. Through the accuracy analysis, the submillimeter accuracy can be made for the final the three-dimensional spatial coordinates which certify that the proposed high-speed videogrammetric technique is a better alternative technique which can replace the traditional transducer technique for monitoring the dynamic response for the shaking table structure.

Numerical solution of a three-dimensional Stefan problem

1970 ◽  
Vol 18 (4) ◽  
pp. 490-498
Author(s):  
Kh. M. Geiman ◽  
L. I. Rubinshtein
Keyword(s):  
Numerical Solution ◽  
Stefan Problem ◽  
Three Dimensional

scholarly journals An Extraction Method of Volleyball Spiking Trajectory and Teaching Based on Wireless Sensor Network

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Meifang Wang ◽  
Zhange Liang
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Extraction Method ◽  
Teaching Method ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Wireless Sensor ◽  
Data Link ◽  
Speed Error ◽  
Spatial Coordinates

It is helpful to analyze volleyball spiking technology and improve spiking quality to extract volleyball spiking trajectory. This article studies the extraction method and teaching method of volleyball spiking trajectory based on a wireless sensor network. The acceleration sensor and gyroscope sensor are used to collect the spiking action state information of volleyball players. The collected information is transmitted to the PC terminal through the wireless sensor network, including physical layer, data link layer, network layer, transmission layer, and application layer, using the LEACH clustering routing protocol algorithm. In the PC terminal, the feedback filtering method is used to preprocess the received information and calculate the integral of each sensor node’s acceleration, connecting the spatial coordinates of each time to obtain the upper limb trajectory in three-dimensional space and realize the trajectory extraction of volleyball spike action. The experimental results show that the position error is less than 0.01 m and the speed error is less than 0.15 m/s. The application of this method in volleyball teaching can effectively improve the quality of volleyball teaching.

scholarly journals Padrão espacial de espécies madeireiras da Amazônia pelo método de coordenadas cartesianas e espaciais

2016 ◽  
Vol 36 (86) ◽  
pp. 115 ◽  
Author(s):  
Tiago Monteiro Condé ◽  
Helio Tonini ◽  
Fernando Da Silva ◽  
Paulo Eduardo Barni ◽  
Carlos Henrique Souza Celes ◽  
...  
Keyword(s):  
Information System ◽  
Forest Management ◽  
Spatial Patterns ◽  
Native Species ◽  
Three Dimensional ◽  
Distribution Patterns ◽  
Timber Species ◽  
Natural Neighbor ◽  
Spatial Coordinates ◽  
Dinizia Excelsa

A utilização de sistemas de informação geográfica (SIG) no planejamento florestal possibilita a análise e o reconhecimento de padrões espaciais das espécies florestais em perfil bidimensional e tridimensional. O objetivo deste estudo foi demonstrar a eficiência do método de coordenadas cartesianas e espaciais (MCCE), método de correção da localização das coordenadas UTM das árvores em concordância com a localização de campo ou cartesianas (X,Y), aliado ao cálculo do índice do vizinho natural (ANND) no reconhecimento e análise de padrões espaciais de quatro espécies comerciais madeireiras em área de manejo florestal em Caracaraí, RR, Brasil. O ANND pressupõe completa aleatoriedade espacial.Simulações foram realizadas em 9 ha, subdivididos em 100 subparcelas de 100 m2 cada. Foram coletados: o diâmetro (DAP > 10 cm), alturas comercial e total, volume comercial e as coordenadas cartesianas (X,Y) e espaciais (UTM). Foram observados padrões espaciais aleatórios para Eschweilera bracteosa e Manilkara huberi. Os padrões espaciais dispersos e raros foram mais observados em Cedrelinga cateniformis e Dinizia excelsa. O MCCE demonstrou ser um método eficiente para o reconhecimento e análise de padrões espaciais de espécies nativas da floresta tropical amazônica, facilitando o planejamento florestal mediante simulações 2D e 3D da floresta.Spatial pattern of Amazonian timber species using cartesian and spatial coordinates methodGeographic information system (GIS) applied to forest analysis permit the recognition and analysis of spatial patterns of species in two and three dimensional. The aim of this study to demonstrate the efficiency of cartesian and spatial coordinates method (MCCE), method of correcting UTM coordinates of trees location in accordance with the location of field or Cartesian (X ,Y), combined with natural neighbor index (ANND) in recognition and analysis of spatial distribution patterns of four commercial timber species in forest management in Caracaraí, Roraima State, Brazil. Simulations were performed on 9 ha, divided into 100 plots of 100 m2 each. Collected data were DBH > 10 cm, commercial and total heights, cartesian coordinates (X,Y) and spatial coordinates (UTM). Random spatial patterns were observed in Eschweilera bracteosa and Manilkara huberi. The dispersed and rare spatial patterns were observed in Dinizia excelsa and Cedrelinga cateniformis. MCCE proved to be an efficient method in the recognition and analysis of spatial patterns of native species from Amazon rain forest, as forest planning becomes easier by 2D and 3D simulations.Index terms: Geographic information system; Forest management; Natural neighbor index 

Sign in / Sign up

Export Citation Format

Share Document