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Internet protocol version 6 defined in 1995 is a successor of the IPv4 protocol. It is being slowly deployed in Internet and so it becomes basis of all Internet communications. Since this process takes a long time IPv6 and IPv4 networks coexist in Internet and some transition mechanisms are needed to ensure their interconnectivity. Several mechanisms came to life based on tunneling or translation basis. This mix of IP versions in Internet induces new network conditions and they should be analyzed by experiments, emulations or simulations. That's why we decided to implement a new extension for network simulator ns-3 to support three IPv6 to IPv4 transition mechanisms. These mechanisms have been applied in various scenarios and undergone testing and verifications.

The H.264/AVC codec provides a superior coding efficiency and an improved network adaptation if compared to older video standards. In this paper we present experimental results obtained by the subjective and objective quality evaluation of the H.264/AVC coded video. Four objective metrics are used: peak signal-to-noise ratio (PSNR), minimum of locally averaged PSNR (local_PSNR), Video Quality Metric (VQM) and Structural Similarity index (SSIM). We have analyzed results of objective and subjective metrics for several CIF sequences and bit rates. Also, we have compared results obtained for H.264/AVC coded sequences with those coded with MPEG-4 Part 2 codec. Results of the subjective quality evaluation show that on the bit rates below 640 kb/s the H.264/AVC codec has achieved an obviously higher video quality, ensured by the objective metrics as well. On the bit rates higher than 640 kb/s the subjective quality of sequences coded by MPEG-4 Part 2 is close to the quality of H.264/AVC coded video, confirmed only by the SSIM and local_PSNR results.

The objective of this paper is to describe the large potential in the flexibility of the digital video terrestrial broadcasting planning in SFN operation mode for spatial complex territory. In the paper it is described that the transmitter antenna radiation patterns should be adopted to achieve maximal territory coverage and restricted interference outside of the network. To fulfill these requirements it will be possible to repeat the same frequency again in other SFN networks in Croatia and in neighbour countries.

This article gives calculation of the relative surface variation, for WiMAX Cell, in percentage for covering particular modo of signal as a function of the WiMAX base station antenna heights. The first part of this paper gives a short description of WiMAX technology. Second part shows transmission modes in the WiMAX air interface, followed in the third part by mathematical approach for calculating the cell relative area covered with respective types of transmission modes. Fourth part of the paper presents simulations results that are obtained by using typical WiMAX system features. Emphasis of this paper is in revealing propagation properties that shape relative surfaces covered with certain mode of signal in a WiMAX cell.

When comparing different interpolation methods, common approach is to use an objective image quality measure that evaluates the numerical errors between the original image and interpolated image. The problem with this approach is impossibility to have original image in two or more different resolutions. Common method is to start with an original image, calculate a lower resolution version of original image (downscaling), and then use different interpolation methods to magnify low resolution image (upscaling). After that original and magnified interpolated images are compared to evaluate difference between them. In our research we found that downscaling process has great influence on results of upscaling. This influence is not properly addressed in references that deal with image interpolation methods. Therefore in this paper we will try to examine how the process of achieving lower resolution image affects picture quality of interpolated images. Our results show that comparison of image interpolation methods depends on downscaling technique, image contents and quality metric.

DICOM has become a standard for medical imaging. Its purpose is to standardize digital medical imaging and data for easy access and sharing. There are many commercial viewers that support DICOM image format and can read metadata, but image displaying is not always optimal. Since mammography images are mostly 12-bit grayscale images, image viewer has to be adapted for correct displaying when different number of bits has to be allocated. Another problem occurs when only a small portion of amplitudes is of interest to display. In this paper a method for efficient presentation of DICOM mammography images in Matlab is introduced. Algorithm that is developed does automatic contrast and brightness adjustments, regardless of bit dept of an image, number of amplitudes higher than zero and the number of allocated bits.