WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Vessel Segmentation in MRI Using a Variational Image Subtraction Approach(Tubitak Scientific & Technological Research Council Turkey, 2014) Nar, Fatih; Saran, Ayse Nurdan; Saran, MuratVessel segmentation is important for many clinical applications, such as the diagnosis of vascular diseases, the planning of surgery, or the monitoring of the progress of disease. Although various approaches have been proposed to segment vessel structures from 3-dimensional medical images, to the best of our knowledge, there has been no known technique that uses magnetic resonance imaging (MRI) as prior information within the vessel segmentation of magnetic resonance angiography (MRA) or magnetic resonance venography (MRV) images. In this study, we propose a novel method that uses MRI images as an atlas, assuming that the patient has an MRI image in addition to MRA/MRV images. The proposed approach intends to increase vessel segmentation accuracy by using the available MRI image as prior information. We use a rigid mutual information registration of the MRA/MRV to the MRI, which provides subvoxel accurate multimodal image registration. On the other hand, vessel segmentation methods tend to mostly suffer from imaging artifacts, such as Rician noise, radio frequency (RF) inhomogeneity, or partial volume effects that are generated by imaging devices. Therefore, this proposed method aims to extract all of the vascular structures from MRA/MRI or MRV/MRI pairs at the same time, while minimizing the combined effects of noise and RF inhomogeneity. Our method is validated both quantitatively and visually using BrainWeb phantom images and clinical MRI, MRA, and MRV images. Comparison and observer studies are also realized using the BrainWeb database and clinical images. The computation time is markedly reduced by developing a parallel implementation using the Nvidia compute unified device architecture and OpenMP frameworks in order to allow the use of the method in clinical settings.Article Prunable collision free random interleaver design(Springer, 2012) Gazi, OrhanIn this article we introduce a new collision free prunable random interleaver. The suggested interleaver is a joint structure involving rectangular and S-random interleaver. It comprises a general model for all kind of collision free prunable random interleavers. In addition, it can be designed for any number of parallel processors and any length of information sequence vector and can be considered also as a template for collision free prunable interleavers. The proposed interleaver can be used with all kind of turbo-like codes. The performance of the proposed interleaver is measured with parallel decodable serially concatenated convolutional codes (PDSCCCs) and compared to the PDSCCCs' performance with collision full S-random interleaver.Conference Object Citation - WoS: 2Citation - Scopus: 2A Two Stage Template Matching Algorithm and Its Implementation on Fpga(Institute of Electrical and Electronics Engineers Inc., 2015) Sever, R.; Töreyin, B.U.; Aktaş, H.In this paper, to decrease the computational cost and number of cycles in Template Matching Algorithm, a novel two-stage algorithm is proposed. The Sum of Absolute Differences method is used for matching. The proposed algorithm is implemented on Field-Programmable-Gate-Array (FPGA). The algorithm is accelerated with the effective usage of Block RAMs distributed on FPGA. Thus, the proposed algorithm became fast enough for real time object tracking applications on UAVs. © 2015 IEEE.Article Citation - WoS: 7Citation - Scopus: 8Collision Free Row Column S-Random Interleaver(Ieee-inst Electrical Electronics Engineers inc, 2009) Yilmaz, A. Oezguer; Gazi, OrhanParallel decodable turbo codes (PDTCs) are suitable for concurrent decoding and hence have low latency. Memory collision issue is an important problem met during parallel processing. In this article, we propose a collision free interleaver for parallel processing operations. The performance of PDTCs is analyzed with the proposed random interleaver preventing the memory collision problem. Distance spectra of PDTCs with the proposed interleaves are computed and compared to those with S-random interleaver.Article Citation - WoS: 14Citation - Scopus: 18Optimal Control of Nonlinear Dynamical Systems Based on a New Parallel Eigenvalue Decomposition Approach(Wiley, 2018) Baleanu, Dumitru; Jajarmi, AminThis manuscript aims to investigate a new approach based on the modal series method and eigenvalue decomposition technique to solve a class of nonlinear optimal control problems. For this purpose, a sequence of decoupled linear two-point boundary value problems is solved iteratively instead of solving the coupled nonlinear two-point boundary value problem derived from the maximum principle. The convergence analysis of the suggested technique is also investigated. In addition, the problem that needs to be solved at each iteration is composed of lower-order decoupled subproblems; hence, they can be solved in parallel. Thus, the new scheme has a parallel computing property improving its computational effectiveness. Numerical simulations and comparative results show that the proposed approach is efficient and provides satisfactory results.Article Citation - WoS: 5Citation - Scopus: 9Fast Decoding of Polar Codes Using Tree Structure(inst Engineering Technology-iet, 2019) Gazi, Orhan; Andi, Alia A.In this study, the authors first propose a tree structure for the successive cancelation (SC) decoding of polar codes. The proposed structure is easy to implement in hardware and suitable for parallel processing operations. Next, using the proposed tree structure, they propose a technique for the fast decoding of polar codes. With the proposed method, it is possible to decode all the information bits simultaneously at the same time, i.e. in parallel. Lastly, they introduce an improved version of the proposed high-speed decoding algorithm. The proposed high-speed decoding approach and its improved version are simulated on the computer environment and their bit error rate performances are compared to the performance of the classical SC method.Article Low Latency Hybrid Structures Involving Convolutional Product Like Codes and Space Time Codes(Springer, 2017) Al-Kattan, Ahmed A. S.; Gazi, OrhanIn this paper, we propose new joint serially concatenated communication structures constructed from convolutional product codes and space time codes. The proposed structures are suitable for parallel processing operations and they have very low decoding latencies compared to their classical counterparts. Use of multi-antennas increases the spectral efficiency of the joint structures.Article Citation - WoS: 1Citation - Scopus: 2Prunable Collision Free Random Interleaver Design(Springer, 2012) Gazi, OrhanIn this article we introduce a new collision free prunable random interleaver. The suggested interleaver is a joint structure involving rectangular and S-random interleaver. It comprises a general model for all kind of collision free prunable random interleavers. In addition, it can be designed for any number of parallel processors and any length of information sequence vector and can be considered also as a template for collision free prunable interleavers. The proposed interleaver can be used with all kind of turbo-like codes. The performance of the proposed interleaver is measured with parallel decodable serially concatenated convolutional codes (PDSCCCs) and compared to the PDSCCCs' performance with collision full S-random interleaver.Article Citation - Scopus: 1Analysis of Parallel Decodable Turbo Codes(Ieice-inst Electronics information Communications Eng, 2012) Gazi, OrhanTurbo codes suffer from high decoding latency which hinders their utilization in many communication systems. Parallel decodable turbo codes (PDTCs) are suitable for parallel decoding and hence have low latency. In this article, we analyze the worst case minimum distance of parallel decodable turbo codes with both S-random interleaver and memory collision free Row-Column S-random interleaver. The effect of minimum distance on code performance is determined through computer simulations.