The performance of wavelength division multiplexing (WDM) networks is highly dependent on the wavelength converter allocation and routing problems. Typically, these problems have been treated as independent problems under dynamic traffic; however, in order to achieved good system's performance, both problems should be dealt with together. To this aim, this work proposes a joint optimization approach where allocations for converters and paths for routing are calculated simultaneously. A multi-objective evolutionary algorithm is proposed to minimize the number of wavelength converters and the overall blocking probability at the same time. Extensive simulations show promising results in the sense that our approach not only generates better trade-off solutions in comparison with an iterative-joint stateof-the-art approach but also constitutes an effective tool to better understand different trade-offs in the design of WDM networks.

Discrete entropy is used to measure the content of an image, where a higher value indicates an image with richer details. Infrared images are capable of revealing important hidden targets. The disadvantage of this type of image is that their low contrast and level of detail are not consistent with human visual perception. These problems can be caused by variations of the environment or by limitations of the cameras that capture the images. In this work we propose a method that improves the details of infrared images, increasing their entropy, preserving their natural appearance, and enhancing contrast. The proposed method extracts multiple features of brightness and darkness from the infrared image. This is done by means of the multiscale top-hat transform. To improve the infrared image, multiple scales are added to the bright areas and multiple areas of darkness are subtracted. The method was tested with 450 infrared thermal images from a public database. Evaluation of the experimental results shows that the proposed method improves the details of the image by increasing entropy, also preserving natural appearance and enhancing the contrast of infrared thermal images.

No abstract

No abstract

No abstract