Suchergebnisse

The content of this thesis is focused on the study of an UWB pulse radar for through the wall vision which has many applications in the military domain (assaults, hostage rescue,…) and in the civil security domain (people search in the rubble, in a fire).For these uses, the real observed scene image is not necessary, only some relevant information is enough: number of persons, position, velocity of movement, etc. It's in this context where we have developed an experimental detection device and some through the wall targets localization techniques. The developed radar consists of a pulse transmitter covering the frequency range from 3GHz to 6GHz, and three independent receivers, combined with some localization algorithms and image reconstruction.The first algorithm is based on a technique of trilateration. Once the theoretical model is presented, many resolutions methods are studied for estimation of the signal propagation distance measurement. The Brent-Dekker method has been chosen for its fast convergence and low number of iterations. Although the trilateration technique is accurate, it does not allow obtaining a scene image, but just locate the targets, without providing their dimensions. Therefore a second approach, based on a "beam forming", has been studied, in order to obtain a 2D scene representation. We have chosen to develop a non-coherent backprojection method, it is the most simple technique which does not require a strong constraint on the signal phase nor on the antenna positions. Different backprojection methods have been proposed: the backprojection with cross correlation, the improved backprojection with cross correlation and bi-cross correlated backprojection. These three methods are based on a fusion of captured information by the receiving antennas and with the obtained information on the "referenced" antennas. This fusion allows improving the image quality progressively.To conclude this work, a perspective is initiated in order to minimize the false detection rate, it is based on the ...

The content of this thesis is focused on the study of an UWB pulse radar for through the wall vision which has many applications in the military domain (assaults, hostage rescue,…) and in the civil security domain (people search in the rubble, in a fire).For these uses, the real observed scene image is not necessary, only some relevant information is enough: number of persons, position, velocity of movement, etc. It's in this context where we have developed an experimental detection device and some through the wall targets localization techniques. The developed radar consists of a pulse transmitter covering the frequency range from 3GHz to 6GHz, and three independent receivers, combined with some localization algorithms and image reconstruction.The first algorithm is based on a technique of trilateration. Once the theoretical model is presented, many resolutions methods are studied for estimation of the signal propagation distance measurement. The Brent-Dekker method has been chosen for its fast convergence and low number of iterations. Although the trilateration technique is accurate, it does not allow obtaining a scene image, but just locate the targets, without providing their dimensions. Therefore a second approach, based on a "beam forming", has been studied, in order to obtain a 2D scene representation. We have chosen to develop a non-coherent backprojection method, it is the most simple technique which does not require a strong constraint on the signal phase nor on the antenna positions. Different backprojection methods have been proposed: the backprojection with cross correlation, the improved backprojection with cross correlation and bi-cross correlated backprojection. These three methods are based on a fusion of captured information by the receiving antennas and with the obtained information on the "referenced" antennas. This fusion allows improving the image quality progressively.To conclude this work, a perspective is initiated in order to minimize the false detection rate, it is based on the ...

Functional zoning provides a basis for establishing a regional development layout with clear functions, reasonable division of labor, and complementary advantages. In the process of urban development, a large number of behaviors such as occupying ecological land and generating a lot of pollution cause damage to the urban ecological environment. Functional zoning of the ecological environment has become an important tool used by the local and central governments to establish a harmonious relationship between socio-economic welfare and the ecological environment in recent years. Guided by the concepts and principles of ecological function zoning, this study applies and extends the methodological approach of ecological function zoning to the scale of urban space. Based on consideration of an evaluation of ecological environment sensitivity, ecosystem service function importance, and socio-economic coercion, this paper divides urban space into four types, namely: ecological environment restoration zone, ecological economy bearing zone, ecological environment preservation zone, and ecological environment protection zone, utilizing a mutually exclusive matrix classification. Taking Taizhou in Jiangsu Province as a pilot study, this paper verifies the actual application of a theoretical model and its technicalities, thus advancing the general case for function zoning of the ecological environment. Furthermore, it outlines measures for ecological environment protection and the industrial development orientation of each function area, thus providing a scientific basis for Taizhou's ecological city development and construction.

Grounded on the social exchange theory (SET), social cognitive theory (SCT), and self-determination theory (SDT), this study aims to explore the mediating role of self-efficacy (SE) and work engagement (WE) on the effect of social support (SS) on job satisfaction (JS) among Chinese ethnic minority kindergarten teachers (KTs). The results show that: (1) SS has a directly significant effect on JS; (2) WE mediates the relationship between SS and JS; and (3) SE mediates the relationship between SS and WE. Although the mediation of SE on the relationship between SS and JS is not found, the posited multiple mediations of SE and WE on the relationship between SS and JS are totally accepted. The results reveal that SS mainland Chinese ethnic minority KTs received can not only have a direct effect on JS but also have an indirect impact through the one-path mediating role of WE and the chain mediating role of SE and WE. The results suggest that governments, supervisors, and sponsors should work together to provide ethnic minority KTs with more prioritized SS from both cultural psychology and financial material and opportunities for facilitating professional knowledge and skills in order to enhance their SE, inspire their WE, and eventually accumulate their JS.