The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform

Marcus Faulkner - One of the best experts on this subject based on the ideXlab platform.

  • The Kriegsmarine and the Aircraft Carrier: The Design and Operational Purpose of the Graf Zeppelin, 1933–1940
    War in History, 2012
    Co-Authors: Marcus Faulkner
    Abstract:

    While the Kriegsmarine’s only aircraft carrier, the uncompleted Graf Zeppelin, has attracted considerable interest over the decades, this has been limited to technical histories of the vessel. This article explores the origins of the programme and what the German navy believed it needed such vessels for. It examines the design process and the proposed method of Operational employment, and seeks to place them in an international context. To date, German efforts have been considered in isolation from the wider developments in aircraft carrier technology during the interwar period. When these are taken into account a more balanced view of the German enterprise emerges.

  • the kriegsmarine and the aircraft carrier the design and Operational Purpose of the graf zeppelin 1933 1940
    War in History, 2012
    Co-Authors: Marcus Faulkner
    Abstract:

    While the Kriegsmarine’s only aircraft carrier, the uncompleted Graf Zeppelin, has attracted considerable interest over the decades, this has been limited to technical histories of the vessel. This article explores the origins of the programme and what the German navy believed it needed such vessels for. It examines the design process and the proposed method of Operational employment, and seeks to place them in an international context. To date, German efforts have been considered in isolation from the wider developments in aircraft carrier technology during the interwar period. When these are taken into account a more balanced view of the German enterprise emerges.

Boonkuan Chung - One of the best experts on this subject based on the ideXlab platform.

  • antenna anechoic chambers
    Encyclopedia of RF and Microwave Engineering, 2005
    Co-Authors: Boonkuan Chung
    Abstract:

    The geometric shape of the anechoic chamber can be optimized to achieve better performance. Microwave absorbers to be installed over the entire inner surfaces of the anechoic chamber must be properly selected. The selection criteria may include the reflectivity levels for normal and oblique incident angles, operating frequency, bandwidth, type of bulk materials, size, shape, weight, mechanical stability, mounting method, fire retardant, and lifespan. The anechoic chamber must be sufficiently large to provide the required dimensions of the quiet zone. Shielding enclosure is provided to prevent extraneous energy from masking measurements of the intended signals. Ventilation, access doors, lighting, cabling, and HVAC (heating–ventilation–air conditioning) shall be incorporated in the design according to the Operational Purpose of the facility. Different construction methods will give rise to varying degrees of imperfection that determine the shielding effectiveness. The performance of the anechoic environment may be evaluated in terms of amplitude ripple and phase change across the quiet zone. There is much interest in trying to reduce the required investment in constructing an anechoic chamber while still maintaining adequate performance. With a suitable computer simulation tool, together with a reasonable absorber model, design of anechoic chamber can be made more economical. Keywords: anechoic chambers (electromagnetic); absorbing media; electromagnetic compatibility; antenna measurements; radar cross sections

  • Encyclopedia of RF and Microwave Engineering - Antenna Anechoic Chambers
    Encyclopedia of RF and Microwave Engineering, 2005
    Co-Authors: Boonkuan Chung
    Abstract:

    The geometric shape of the anechoic chamber can be optimized to achieve better performance. Microwave absorbers to be installed over the entire inner surfaces of the anechoic chamber must be properly selected. The selection criteria may include the reflectivity levels for normal and oblique incident angles, operating frequency, bandwidth, type of bulk materials, size, shape, weight, mechanical stability, mounting method, fire retardant, and lifespan. The anechoic chamber must be sufficiently large to provide the required dimensions of the quiet zone. Shielding enclosure is provided to prevent extraneous energy from masking measurements of the intended signals. Ventilation, access doors, lighting, cabling, and HVAC (heating–ventilation–air conditioning) shall be incorporated in the design according to the Operational Purpose of the facility. Different construction methods will give rise to varying degrees of imperfection that determine the shielding effectiveness. The performance of the anechoic environment may be evaluated in terms of amplitude ripple and phase change across the quiet zone. There is much interest in trying to reduce the required investment in constructing an anechoic chamber while still maintaining adequate performance. With a suitable computer simulation tool, together with a reasonable absorber model, design of anechoic chamber can be made more economical. Keywords: anechoic chambers (electromagnetic); absorbing media; electromagnetic compatibility; antenna measurements; radar cross sections

Gregoire Mercier - One of the best experts on this subject based on the ideXlab platform.

  • IGARSS - Progressive change detection in time series of SAR images
    2010 IEEE International Geoscience and Remote Sensing Symposium, 2010
    Co-Authors: Gregoire Mercier
    Abstract:

    The aim of this paper is to present a general framework for change detection in a time series of radar images, for an Operational Purpose and in the context of environmental monitoring. The change detection procedure is turned into the framework of detecting a random signal into the noise; the detection of this signal leads to the detection of a change in the time series. This framework is based on a non-parametric detection method that assume a sparse representation of the data. When using radar images, the speckle noise invalidates the hypothesis of sparsity. Then a pre-processing technique is required to provide an appropriate sparse representation of data, whatever the initial noise characteristics.

  • IGARSS (4) - General framework on change detection in a sparse domain
    2009 IEEE International Geoscience and Remote Sensing Symposium, 2009
    Co-Authors: Abdourrahmane M. Atto, Gregoire Mercier, Dominique Pastor
    Abstract:

    The paper presents a general framework for change detection in radar images, for an Operational Purpose and in the context of environmental monitoring. This framework is based on a processing which provides highly sparsifiable representations of data. This processing is called turbo-median and is a combination of the sample median robustness and the turbo principle for iteratively correcting errors. The turbo-median processing of a scene is an homogenized representation based on an iterative median and which consists in spreading the statistically more robust measurements of the scene under consideration over the size of the image representing this scene. It allows for reducing the change detection problem into the problem of detecting a signal, with unknown distribution, in additive noise.

Dominique Pastor - One of the best experts on this subject based on the ideXlab platform.

  • IGARSS (4) - General framework on change detection in a sparse domain
    2009 IEEE International Geoscience and Remote Sensing Symposium, 2009
    Co-Authors: Abdourrahmane M. Atto, Gregoire Mercier, Dominique Pastor
    Abstract:

    The paper presents a general framework for change detection in radar images, for an Operational Purpose and in the context of environmental monitoring. This framework is based on a processing which provides highly sparsifiable representations of data. This processing is called turbo-median and is a combination of the sample median robustness and the turbo principle for iteratively correcting errors. The turbo-median processing of a scene is an homogenized representation based on an iterative median and which consists in spreading the statistically more robust measurements of the scene under consideration over the size of the image representing this scene. It allows for reducing the change detection problem into the problem of detecting a signal, with unknown distribution, in additive noise.

Jelena Stepanova - One of the best experts on this subject based on the ideXlab platform.

  • Improvement of the technology of accelerated passage of low-capacity car traffic on the basis of scheduling of grouped trains of Operational Purpose
    Procedia Computer Science, 2019
    Co-Authors: Аndrii Prokhorchenko, Larysa Parkhomenko, Andrii Kyman, Viacheslav Matsiuk, Jelena Stepanova
    Abstract:

    Abstract One of the main directions of increasing the efficiency of the operating model of the railways functioning is the reduction of logistics costs in the transportation of wagon and group shipments due to the improvement of the technology for accelerating the passage of low-capacity railcar traffic on the basis of the organization of the circulation of grouped trains of Operational Purpose, taking into account the synchronization of the plan for the formation of grouped trains with a schedule of traffic. In order to provide the railway system with the properties of adaptive control of low-capacity railcar traffic at the networks of large dimensions, an optimization mathematical model has been developed. To optimize this mathematical model, it is proposed to use a real coded genetic algorithm. The coding and decoding process of the chromosome of the genetic algorithm has been formed, which reflects the technological features of the implementation of the train formation plan of the grouped trains of Operational Purpose. This approach will allow to increase the level of organization of transportations and to accelerate the delivery of cargoes and to increase the competitiveness of railways in the market of transport services.