In this paper, we propose a low bit rate video coding procedure in the discrete cosine transform (DCT) domain that is based in an embedded zerotree algorithm and uses decimation and interpolation. Theory for decimation/interpolation in the DCT domain is presented, and its implementation with fast algorithms is shown. Motivated by the compositing of several video sources in multipoint video conferencing, we propose a new method for single streams that uses the proposed DCT-decimation in the encoder and the corresponding DCT-interpolation in the decoder. Decimated video frames are encoded using an embedded zerotree and an adaptive arithmetic coder to improve the quality of the decoded videos. Zerotree coding is a progressive coding method that quantizes amplitudes of DCT coefficients of video frames into bit streams with increasing precision. Embedded coding scheme depends on coding a symbol by an adaptive arithmetic encoder as soon as the symbol is obtained by the zerotree coding. Zerotree coder gives flexibility of controlling the bit rate precisely at given target bit rate. Compared to conventional coding our proposed algorithm achieves peak signal-to-noise ratio improvements at low bit rate video coding.

It is important to solve the autonomous mapping problem with high accuracy using limited energy resources in an environment without prior knowledge and/or signal. Visual Simultaneous Localization and Mapping (SLAM) deals with the problem of determining the position and orientation of an autonomous vehicle or robot with various on-board sensors, and simultaneously creating a map of environment with low energy consumption. However visual SLAM methods require high processing performance for real-time operations. Also, processing capability of the hardware is limited by the power constraints. Therefore, it is necessary to compare the processing load and power consumption of visual SLAM methods for autonomous vehicles or robots. For visual SLAM methods, although there are different comparison studies, there is no comprehensive computational cost analysis covering different datasets and important parameters including absolute trajectory error, RAM Usage, CPU load, GPU load, with total power consumption. In this paper, ORB-SLAM2, Direct Sparse Odometry (DSO), and DSO with Loop Closure (LDSO), which are state of the art visual SLAM methods, are compared. Besides the performance of these methods, energy consumption and resource usage are evaluated allowing the selection of the appropriate SLAM method.

Hyperspectral sensors generate images in narrow bands in continuous manner with hundreds of spectral bands. The data with large number of bands require more processing power to classify. To decrease the redundancy in hyperspectral images and increase classifying efficiency with less number of bands, dimension reduction techniques are applied. In this paper, linear and non-linear dimension reduction methods are compared in classification performance and calculation time.

Rapid development in mobile communication technologies has brought high speed and capacity requirements. With the introduction of mobile networks in many areas of life, such as smart homes and cities, virtual reality and augmented reality applications, health, education, agriculture and industry, there is a high increase in the amount of data usage. For this reason, standardization studies of the fifth generation (5G) technologies are continuing rapidly. In addition to this, it is planned to use frequency bands of 30-300 GHz, which are not yet in use for the 5G mobile technologies, also known as the millimeter wave (mmW), since the frequency bands allocated to the current mobile technologies are insufficient to meet the needs of the users. The attenuation of the signals in the upper bands of the frequency spectrum increases due to the distance. Since the mmW bands lie at the high frequency spectrum, they are also affected by atmospheric phenomena, such as rain and fog, and are subject to additional weakening. In this study, the weaknesses of the mmW frequency bands planned to be used in 5G technologies due to various atmospheric effects are analyzed comparatively. As a result of the studies carried out, it has been shown that the obtained attenuation rates need to be taken into consideration in network planning for the mmW frequency bands in 5G mobile networks.