- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Beam-Doppler Unitary ESPRIT for Multitarget DOA Estimation
摘要： High-resolution direction of arrival (DOA) estimation is a critical issue for mainbeam multitarget tracking in ground-based or airborne early warning radar system. A beam-Doppler unitary ESPRIT (BD-UESPRIT) algorithm is proposed to deal with this problem. Firstly, multiple snapshots without spatial aperture loss are obtained by using the technique of time-smoothing. Then the conjugate centrosymmetric discrete Fourier transform (DFT) matrix is used to transform the extracted data into beam-Doppler domain. Finally, the rotational invariance property of the space-time beam is exploited to estimate DOA of the target. The DOA estimation accuracy is improved greatly because the proposed algorithm takes full advantage of temporal information of the signal. Furthermore, the computational complexity of the presented algorithm is reduced dramatically, because the degree of freedom after beam transformation is very small and most of the operations are implemented in real-number domain. Numerical examples are given to verify the effectiveness of the proposed algorithm.
关键词： computational complexity,DOA estimation,time-smoothing,ESPRIT,beam-Doppler domain
更新于2025-09-23 15:22:29
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Quantum gate identification: Error analysis, numerical results and optical experiment
摘要： The identification of an unknown quantum gate is a significant issue in quantum technology. In this paper, we propose a quantum gate identification method within the framework of quantum process tomography. In this method, a series of pure states are applied to the gate and then a fast state tomography on the output states is performed and the data are used to reconstruct the quantum gate. The algorithm has computational complexity O(d3) with the system dimension d. The identification approach is compared with the maximum likelihood estimation method for the running time, which shows an efficiency advantage of our method. An error upper bound is established for the identification algorithm and the robustness of the algorithm against impurities in the input states is also tested. We perform a quantum optical experiment on a single-qubit Hadamard gate to verify the effectiveness of the identification algorithm.
关键词： Quantum system,Quantum tomography,Quantum gate identification,Computational complexity
更新于2025-09-23 15:22:29
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Robust and distortion control dual watermarking in LWT domain using DCT and error correction code for color medical image
摘要： This paper presents lifting wavelet transform (LWT) and discrete cosine transform (DCT) based robust watermarking approach for tele-health applications. For identity authentication, 'signature watermark' of size '64 × 64' and 'patient report' of size '80' characters are hiding into the host medical image. Further, the signature watermark is encrypted by message-digest (MD5) and 'patient report' is encoded by BCH error correcting code before embedding into the host image. Experimental demonstrations indicate that the method provides sufficient robustness and security against various attacks without significant distortion between cover and watermarked image. Further, our results proved that the method offer NC value more than 0.9214 for most of the considered attacks. Furthermore, it is evident from results our method shows the improvement in robustness to previously reported techniques under consideration while providing low computational complexity.
关键词： LWT,MD5,Robustness,Complexity,DCT,BCH
更新于2025-09-23 15:22:29
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[IEEE 2017 IEEE 17th International Conference on Bioinformatics and Bioengineering (BIBE) - Washington, DC (2017.10.23-2017.10.25)] 2017 IEEE 17th International Conference on Bioinformatics and Bioengineering (BIBE) - A novel low-complexity framework in ultra-wideband imaging for breast cancer detection
摘要： In this research work, a novel framework is proposed as an efficient successor to traditional imaging methods for breast cancer detection in order to decrease the computational complexity. In this framework, the breast is divided into segments in an iterative process and in each iteration, the one having the most probability of containing tumor with lowest possible resolution is selected by using suitable decision metrics. After finding the smallest tumor-containing segment, the resolution is increased in the detected tumor-containing segment, leaving the other parts of the breast image with low resolution. Our framework is applied on the most common used beamforming techniques, such as delay and sum (DAS) and delay multiply and sum (DMAS) and according to simulation results, our framework can decrease the computational complexity significantly for both DAS and DMAS without imposing any degradation on accuracy of basic algorithms. The amount of complexity reduction can be determined manually or automatically based on two proposed methods that are described in this framework.
关键词： breast cancer detection,low complexity computational methods,DAS,DMAS,Microwave imaging
更新于2025-09-23 15:21:21
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Direct Laser Writing of Mid-Infrared Straight and Bent Waveguides
摘要： The Hausdorff distance (HD) between two point sets is a commonly used dissimilarity measure for comparing point sets and image segmentations. Especially when very large point sets are compared using the HD, for example when evaluating magnetic resonance volume segmentations, or when the underlying applications are based on time critical tasks, like motion detection, then the computational complexity of HD algorithms becomes an important issue. In this paper we propose a novel efficient algorithm for computing the exact Hausdorff distance. In a runtime analysis, the proposed algorithm is demonstrated to have nearly-linear complexity. Furthermore, it has efficient performance for large point set sizes as well as for large grid size; performs equally for sparse and dense point sets; and finally it is general without restrictions on the characteristics of the point set. The proposed algorithm is tested against the HD algorithm of the widely used national library of medicine insight segmentation and registration toolkit (ITK) using magnetic resonance volumes with extremely large size. The proposed algorithm outperforms the ITK HD algorithm both in speed and memory required. In an experiment using trajectories from a road network, the proposed algorithm significantly outperforms an HD algorithm based on R-Trees.
关键词： computational complexity,algorithm,evaluation,Hausdorff distance,runtime analysis
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Enhanced Kerr Optical Nonlinearity of Waveguides Integrated with Graphene Oxide
摘要： The Hausdorff distance (HD) between two point sets is a commonly used dissimilarity measure for comparing point sets and image segmentations. Especially when very large point sets are compared using the HD, for example when evaluating magnetic resonance volume segmentations, or when the underlying applications are based on time critical tasks, like motion detection, then the computational complexity of HD algorithms becomes an important issue. In this paper we propose a novel efficient algorithm for computing the exact Hausdorff distance. In a runtime analysis, the proposed algorithm is demonstrated to have nearly-linear complexity. Furthermore, it has efficient performance for large point set sizes as well as for large grid size; performs equally for sparse and dense point sets; and finally it is general without restrictions on the characteristics of the point set. The proposed algorithm is tested against the HD algorithm of the widely used national library of medicine insight segmentation and registration toolkit (ITK) using magnetic resonance volumes with extremely large size. The proposed algorithm outperforms the ITK HD algorithm both in speed and memory required. In an experiment using trajectories from a road network, the proposed algorithm significantly outperforms an HD algorithm based on R-Trees.
关键词： computational complexity,algorithm,evaluation,Hausdorff distance,runtime analysis
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Solder Bond Degradation of Fielded PV Modules: Climate Dependence of Intermetallic Compound Growth
摘要： Energy-ef?cient resource allocation is investigated for multi-pair massive MIMO amplify-and-forward relay systems, where a dedicated relay assists pairwise information exchange among many pieces of single-antenna user equipment (UE). The system energy ef?ciency (EE) is theoretically analyzed by employing large system analysis and random matrix theory. This analytical result provides excellent approximation for the system with a moderate number of antennas, and it also enables several ef?cient algorithms, working with a different knowledge of channel state information (CSI), to maximize the system EE by scheduling the optimal numbers of relay antennas and UE pairs as well as the corresponding relay transmission power. In contrast to the conventional resource allocation schemes, the proposed algorithms avoid complicated matrix calculations and the instantaneous CSI of small-scale fading; therefore, they are computationally ef?cient with low CSI overhead. The proposed optimization framework sheds light on the optimized system con?gurations, and it also offers an ef?cient way to achieve EE-oriented resource allocation for the multi-pair massive MIMO relay systems.
关键词： Energy-ef?cient,resource allocation,low-complexity,massive MIMO relay
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE Workshop on Complexity in Engineering (COMPENG) - Florence, Italy (2018.10.10-2018.10.12)] 2018 IEEE Workshop on Complexity in Engineering (COMPENG) - Fractal-Radiomics as Complexity Analysis of CT and MRI Cancer Images
摘要： Cancer is the second leading cause of death globally. Early diagnosis can allow intervention to reduce mortality but due to cancer complex structure and spatial heterogeneity among different tumors and within each lesion, it is difficult to differentiate it from healthy tissue using conventional imaging techniques. Quantification of its complexity can be a prognostic tool for fighting this disease. In recent years, clinical imaging allows this quantification thanks to Radiomics, which extracts features from images. In this study, Fractal Dimension (FD) and Lacunarity (L) in computed tomography (CT) and magnetic resonance (MR) images for different kinds of cancer were examined using box counting method. Our aim is to highlight the potentiality of features based on fractal analysis, in order to obtain new indicators able to detect tumor spatial complexity and heterogeneity. The results indicated that both FD and L show problems linked to the lack of connection between complexity estimated with Radiomics and the underlying biological model.
关键词： cancer heterogeneity,lacunarity,complexity,fractal analysis,cancer,Radiomics
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - Sheffield (2018.7.8-2018.7.11)] 2018 IEEE 10th Sensor Array and Multichannel Signal Processing Workshop (SAM) - A Multi-Channel Partial-Update Algorithm for Sea Clutter Suppression in Passive Bistatic Radar
摘要： Sea clutters with Doppler-varying spectrum exert a notable negative impact on the detection performance, especially with low-velocity targets, when a passive bistatic radar is employed to detect sea-surface targets. One feasible solution is to modulate the reference signal onto the Doppler dimension and, as such, a filter with a wide notch and sharp edges can be obtained to suppress the residual clutters. However, to achieve this goal, a considerably high computational complexity is demanded in the existing two-dimensional (2D) adaptive filters. In this context, a novel 2D partial-update normalized least mean square algorithm is proposed to reduce the computational load, as well as to yield a superior clutter suppression performance. The effectiveness of the proposed approach is verified by real-data experiments.
关键词： Passive bistatic radar (PBR),multi-channel filtering,adaptive cancellation,sea clutter,computational complexity
更新于2025-09-23 15:21:01
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Complexity mapping of a photonic integrated circuit laser using a correlation-dimension-based approach
摘要： Quantifying complexity from experimental time series generated by nonlinear systems, including laser systems, remains a challenge. Methods that are based on entropy, such as permutation entropy (PE), have proven to be useful tools for the relative measure of time series complexity. However, the numerical value of PE is not readily linked to a specific type of dynamical output. Thus, the quest to calculate quantitatively meaningful fractal dimension values, such as the correlation dimension (CD), from experimental signals, is still important. A protocol for calculating minimum gradient values and their spread, an integral part of CD analysis, is used here. Minimum gradient values with small spread are presented as approximate CD values. Here-in we report mapping these values, derived from analyzing experimental time series, obtained from a 4-section photonic integrated circuit laser (PICL) across a large parameter space. The PICL is an integrated form of a semiconductor laser subject to controllable optical feedback system. The minimum gradient/approximate CD mapping shows it has some qualitatively different map regions in its dynamics as compared to a free-space-based equivalent system. We show that the minimum gradient values give insight into the dynamics even when approximate CD values cannot be determined. The agreement between the qualitative features of permutation entropy mapping and minimum gradient/approximate CD value mapping provides further support for this. Regions of time series with close to periodic and quasi-periodic dynamics are identifiable using minimum gradient value maps.
关键词： semiconductor lasers,integrated optoelectronic devices,nonlinear dynamics,complex systems,Chaos,complexity
更新于2025-09-23 15:19:57