Measures of Bivariate Association between Two Spatial Variables

2012 ◽  
pp. 351-390
Keyword(s):  
Spatial Variables ◽  
Bivariate Association

Community dynamics in highland watersheds

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Community Dynamics ◽  
Community Organization ◽  
Current Knowledge ◽  
Central Process ◽  
Spatial Variables ◽  
Research Areas ◽  
Local Extinctions ◽  
Metacommunity Dynamics ◽  
Natural Communities

Chapter 6 presents the interaction between space and time in determining the organization of natural communities in high altitude heterogeneous waterscapes. After explaining why high altitude waters represent suitable models for examining metacommunity organization, the chapter focuses on dispersal—a central process to allow colonization and establishment of populations in remote localities and to counter local extinctions. Community organization patterns are then described for a variety of organisms living in high altitude waters, from microbes to invertebrates to fish and birds. These patterns reveal that both environmental and spatial variables are generally involved in species assembling. Examples of studies on directional spatial processes (e.g. through wind and water flow), waterscape genetics, and temporal variability (synchrony/asynchrony) are highlighted as promising research areas to increase the current knowledge on high altitude metacommunity dynamics.

DIFFERENTIAL GAMES OF FRACTIONAL ORDER WITH DISTRIBUTED PARAMETERS

2021 ◽  
Vol 4 ◽  
pp. 38-47
Author(s):  
Mashrabzhan Mamatov ◽  
◽  
Jalolkon Nuritdinov ◽  
Egamberdi Esonov ◽  
◽  
...  
Keyword(s):  
Differential Games ◽  
Fractional Order ◽  
Sufficient Conditions ◽  
Initial Position ◽  
Difference Approximation ◽  
Pursuit Problem ◽  
Spatial Variables ◽  
Terminal Set ◽  
Distributed Parameters ◽  
Discrete Game

The article deals with the problem of pursuit in differential games of fractional order with distributed parameters. Partial fractional derivatives with respect to time and space variables are understood in the sense of Riemann - Liouville, and the Grunwald-Letnikov formula is used in the approximation. The problem of getting into some positive neighborhood of the terminal set is considered. To solve this problem, the finite difference method is used. The fractional Riemann-Liouville derivatives with respect to spatial variables on a segment are approximated using the Grunwald-Letnikov formula. Using a sufficient criterion for the existence of a fractional derivative, a difference approximation of the fractional-order derivative with respect to time is obtained. By approximating a differential game to an explicit difference game, a discrete game is obtained. The corresponding pursuit problem for a discrete game is formulated, which is obtained using the approximation of a continuous game. The concept of the possibility of completing the pursuit, a discrete game in the sense of an exact capture, is defined. Sufficient conditions are obtained for the possibility of completing the pursuit. It is shown that the order of approximation in time is equal to one, and in spatial variables is equal to two. It is proved that if in a discrete game from a given initial position it is possible to complete the pursuit in the sense of exact capture, then in a continuous game from the corresponding initial position it is possible to complete the pursuit in the sense of hitting a certain neighborhood. A structure for constructing pursuit controls is proposed, which will ensure the completion of the game in a finite time. The methods used for this problem can be used to study differential games described by more general equations of fractional order.

scholarly journals Divergencias y convergencias para asegurar la actividad agrícola en Ecuador: análisis de la parroquia Chuquiribamba (Loja) / Divergences and convergences to ensure agriculture in Ecuador: analysis of the Chuquiribamba Parrish (Loja)

2018 ◽  
Author(s):  
Verónica Iñiguez-Gallardo ◽  
Renato Serrano-Barbecho ◽  
Fabián René Reyes Bueno
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Spatial Data ◽  
Small Scale ◽  
Agricultural Activity ◽  
Spatial Variables ◽  
The People ◽  
Family Economy ◽  
Southern Ecuador ◽  
Parcel Size

La regulación de uso del suelo es un continuo debate en el proceso de planificación territorial, sobre todo en Ecuador, donde la agricultura a pequeña escala es uno de los pilares de la economía familiar para un amplio porcentaje de habitantes del sector rural. Por esta razón, identificar las variables requeridas para mantener la actividad agrícola es una necesidad y obligación. El objetivo principal de este artículo es identificar las variables espaciales que inciden sobre la probabilidad de mantener la actividad agrícola, de acuerdo con las expectativas de la gente y las características del territorio. Para ello, se comparan datos de percepción de los pobladores sobre variables tales como superficie predial, distancia a carretera, a canales de riego y a mercados, con datos espaciales de estas mismas variables. El área de estudio es la Parroquia Chuquiribamba, perteneciente al cantón Loja, al sur del Ecuador, por ser una de las principales fuentes agrícolas del sector. Los resultados sugieren convergencias entre las percepciones de la gente y las variables espaciales necesarias para asegurar la actividad agrícola, así como divergencias respecto a la normativa que regula el tamaño mínimo predial.  Abstract Land-use regulation is an ongoing debate in the process of land-use planning. This is particularly true for a country such as Ecuador, where small-scale agriculture is one of the pillars of the family economy for a large percentage of inhabitants of the rural sector.  In this context, identifying the necessary variables for ensuring agricultural activities is a need and an obligation. The main objective of this article is to identify the spatial variables that affect the probability of maintaining agricultural activity, according to the expectations of the people and the characteristics of the territory. We compare data regarding the perceptions of the people of variables such as parcel size, road, irrigation and market proximity, with spatial data of the same variables. The area of study is the Chuquiribamba Parish, located in Canton Loja, in southern Ecuador. We selected it due to its agricultural importance in the Canton. The results suggest convergences between the perceptions of the people and the spatial variables necessary to safeguard agriculture, as well as divergences with the normative regulating the minimum parcel-size. 

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