http://dr.lib.sjp.ac.lk/handle/123456789/8495 2026-04-23T10:32:47Z http://dr.lib.sjp.ac.lk/handle/123456789/8576 Efficient Ultrasound Video Streaming using HEVC Sivapatham, S; de Alwis, C; Dharmaweera, M.N; Wijewardhana, U.L This work investigates the feasibility of using High Efficiency Video Coding (HEVC) to stream ultra-sound scan video over mobile networks. HEVC is designed to efficiently encode and decode high volume video to achieve a significant bit-rate saving while preserving the video quality. Even though HEVC is capable of encoding and decoding movies, the efficient usage of HEVC specifically for ultra-sound scan video streaming is not investigated thoroughly. In response, we investigate the feasibility of using HEVC to encode a full-high-definition abdominal ultrasound scan video in order to efficiently stream across a mobile network and decode in the receiver at an acceptable quality. Ultra-sound scan videos are encoded at different quantization parameters to produce video sequences at different bit-rates. These video sequences are transmitted across a mobile network and the received video is evaluated quantitatively and qualitatively. Initial results of the experiment are presented in this paper. These results indicate that at least 6 Mbps of bandwidth is required in order to transmit a full-high-definition ultrasound scan video at an acceptable quality. Hence, the PSNR(Peak Signal to Noise Ratio) of the received video sequence should be at least 50. These results also raise the requirement to develop more efficient HEVC schemes and transmission techniques to facilitate real time ultra-sound scan video streaming over mobile networks in advanced telemedicine applications. 2018-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/8570 Lapped Transforms based Image Recovery for Block Compressed Sensing Wijewardhana, U.L; Codreanu, M 2018-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/8569 Robust Regenerator Allocation in Nonlinear Flexible-Grid Optical Networks With Time-Varying Data Rates Yan, L; Xu, Y; Brandt-Pearce, M; Dharmaweera, M.N; Agrell, E Predeployment of regenerators in a selected subset of network nodes allows service providers to achieve rapid provisioning of traffic demands, high utilization, and reduced network operational costs, while still guaranteeing lightpath quality of transmission. Enabled by bandwidth-variable transceivers in flexible-grid optical networks, optical channel bandwidths are no longer fixed but constantly changing according to real-time communication requirements. Consequently, the data-rate-variable traffic together with other new network features introduced by flexible-grid networks will render the regenerator allocation very difficult due to the complicated network states. In this paper, we investigate how to allocate regenerators robustly in flexible-grid optical networks to combat physical-layer impairments when the data rates of traffic demands are random variables. The Gaussian noise model and a modified statistical network assessment process framework are used to characterize the probabilistic distributions of physical-layer impairments for each demand, based on which a heuristic algorithm is proposed to select a set of regenerator sites with minimum blocking probabilities. Our method achieves the same blocking probabilities with on average 10% less regenerator sites compared with the greedy constrained-routing regenerator allocation method, and obtains blocking probabilities two orders of magnitude lower than that of the routing and reach method with the same number of regenerator sites. 2018-01-01T00:00:00Z