944 results on '"DOA"'
Search Results
2. Off-Grid Underwater Acoustic Source Direction-of-Arrival Estimation Method Based on Iterative Empirical Mode Decomposition Interval Threshold.
- Author
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Xing, Chuanxi, Tan, Guangzhi, and Dong, Saimeng
- Subjects
- *
MACHINE learning , *SINGULAR value decomposition , *DIRECTION of arrival estimation , *ACOUSTIC radiators , *SIGNAL-to-noise ratio - Abstract
To solve the problem that the hydrophone arrays are disturbed by ocean noise when collecting signals in shallow seas, resulting in reduced accuracy and resolution of target orientation estimation, a direction-of-arrival (DOA) estimation algorithm based on iterative EMD interval thresholding (EMD-IIT) and off-grid sparse Bayesian learning is proposed. Firstly, the noisy signal acquired by the hydrophone array is denoised by the EMD-IIT algorithm. Secondly, the singular value decomposition is performed on the denoised signal, and then an off-grid sparse reconstruction model is established. Finally, the maximum a posteriori probability of the target signal is obtained by the Bayesian learning algorithm, and the DOA estimate of the target is derived to achieve the orientation estimation of the target. Simulation analysis and sea trial data results show that the algorithm achieves a resolution probability of 100% at an azimuthal separation of 8° between adjacent signal sources. At a low signal-to-noise ratio of −9 dB, the resolution probability reaches 100%. Compared with the conventional MUSIC-like and OGSBI-SVD algorithms, this algorithm can effectively eliminate noise interference and provides better performance in terms of localization accuracy, algorithm runtime, and algorithm robustness. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Novel approaches for target parameter extraction with eigenvalue thresholding and Dolph–Chebyshev windowing in multiple‐input multiple‐output (MIMO) radar system.
- Author
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Jagtap, Sheetal G. and Kunte, Ashwini S.
- Subjects
- *
MIMO radar , *MARINE electronics , *RADAR , *EIGENVALUES , *MULTIPLE Signal Classification , *RADIO waves - Abstract
Summary Multiple‐input multiple‐output (MIMO) radar, employing multiple transmitters and receivers, enhances radar capabilities. It detects and tracks objects like aircraft and ships using radio waves. Compared with traditional phased‐array radar, MIMO systems offer greater flexibility, improving angular resolution and target detection. Researchers focus on direction of arrival (DoA) evaluation for closely spaced targets. Effective beamforming and accurate DoA estimation are crucial for MIMO radar performance. This study explores two methods: Capon beamforming with Dolph–Chebyshev windowing and the MUSIC algorithm with Eigenvalue thresholding. Tested under low signal‐to‐noise ratio (SNR) and fewer snapshots, these techniques notably reduce side lobes and enhance angular resolution, validated by experiments. Additionally, the suppression of side lobes significantly improves the clarity and accuracy of target detection, minimizing potential interference and false targets. This enhancement in side lobe suppression facilitates a more precise spatial differentiation between multiple targets, thus contributing to the overall effectiveness and reliability of MIMO radar systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Improved multiple-Toeplitz matrices reconstruction method using quadratic spatial smoothing for coherent signals DOA estimation
- Author
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Qi, Bingbing, Xu, Lijun, and Liu, Xiaogang
- Published
- 2024
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5. Spatial Spectrum Estimation of Weak Scattering Wave Signal in Range-Doppler Domain.
- Author
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Xu, Hang, Ma, Hong, Wang, Li, Jin, Jiang, Zhang, Hua, and Liu, Xiaodong
- Subjects
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AUTOMATIC dependent surveillance-broadcast , *MULTIPLE Signal Classification , *SINGULAR value decomposition , *SIGNAL-to-noise ratio , *DOPPLER effect , *DIRECTION of arrival estimation - Abstract
How to enhance the desired signal with low signal-to-noise ratio (SNR) is a difficult problem in the estimation process of the direction-of-arrival (DOA) of the target scattering wave signal. In this paper, the feasibility of spatial spectrum estimation in the Range-Doppler (RD) domain is analyzed in principle, and the SNR gain expression of weak scattering wave signal is derived when constructing multi-snapshots virtual array data. On this basis, the mutual eigenvector singular value decomposition (MESVD) method based on RD domain mode excitation is proposed, which can robustly and effectively estimate the direction of the coherent weak signals. Simulation experiments verify that the RD domain spectral estimation method has the ability to simultaneously obtain the direction of multiple weak target scattering waves, and the direction-finding accuracy can reach the Cramer–Rao bound (CRB) of conventional spectral estimation method. The results of Monte Carlo experiments show that the root-mean-square-error (RMSE) of azimuth estimation of RD domain spatial spectrum estimation method is 5.76° lower than that of a conventional multiple signal classification (MUSIC) method. In addition, the practicability of the proposed method is demonstrated by comparing the DOA estimation results of a set of real data with Automatic Dependent Surveillance-Broadcast (ADS-B) data. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Multiplicative Basis Function Based Adaptive DOA Estimation in Optimal MIMO Sparse Antenna Reconfiguration Model.
- Author
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Anughna, Narayanaswamy and Ramesha, Muniyappa
- Abstract
Direction of arrival (DOA) estimation using sparse signal representation has gained significant attention in recent decades. The spatial signals utilized for DOA estimation are reconstructed through a novel compressive sensing (CS) approach. In this study, we used a CS approach to ascertain the adaptive underdetermined DOA for multiple inputs and multiple output (MIMO) sparse media. Accurate DOA estimation through the CS approach contributes to enhanced signal investigation and the suppression of undesired noise in a sparse channel. The method proposed herein encompasses the development and execution of a novel multiplicative basis function known as the multi-kernel supported non-negative sparse Bayesian learning (NNSBL) algorithm, which is implemented on predefined grid values. Concurrently, stochastic grey wolf optimization (GWO) is virtually applied to increase the degrees of freedom (DOF) on a minimum redundancy array (MRA) while considering an optimal antenna reconfiguration model. The advantages of this proposed approach include the generation of a distinct manifold matrix for precise beam steering, resulting in improved DOA estimation accuracy. Additionally, an augmentation of DOF using GWO was observed, with low computational complexity. The simulated result of proposed algorithm leads to the attainment of optimal minimum root mean square error (RMSE) across various optimal wavelengths of the stochastic sources. Finally, a comparative analysis of RMSE and convergence plots confirms the superior performance and high potentiality of the proposed method in comparison to existing techniques across different SNR values. Notably, there is significant reduction in RMSE which is suitable for precise DOA estimation in signal processing applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
7. ВИЗНАЧЕННЯ НАПРЯМКУ НА ДЖЕРЕЛО РАДІОВИПРОМІНЮВАННЯ ЗА ДОПОМОГОЮ ДВОКАНАЛЬНОГО SDR ПРИЙМАЧА.
- Author
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Бруско, А. В., Мирончук, О. Ю., and Олійник, М. В.
- Abstract
The topic of radio direction finding is quite broad and complex, as it has applications in many areas of life, from domestic to industrial. Despite the large number of possible systems and their purposes, there are accessible solutions which allow starting research in this field of radio engineering and signal processing and can also serve as a basis for further development of specialized systems. One of such solutions is SDR transceivers and receivers. Software-defined radio is a radio-electronic device that contains all the necessary components for digitizing received signals (in case of receivers) and reproducing a specified signal (transmission, in case of transceivers). Structurally, these devices contain a heterodyne for signal shifting in the frequency range, as well as ADC/DAC for reception and transmission, respectively. This work implements a system for determining the direction to the source of a FM radio signal based on a dual-channel SDR receiver and a personal computer. Direction finding is performed using the MUSiC algorithm. GNU Radio and Matlab software solutions are used for signal processing. Both programs are widely used in digital signal processing. The GNU Radio is unique because of its graphical block editor that is used for signal reception, processing, storage, and transmission. Matlab is known for its versatility and is used in many areas besides radio technology. It’s use in this work is justified by its convenient handling of matrices, and therefore the MUSiC algorithm was presented in detail and implemented accordingly. The MUSiC algorithm belongs to methods for estimating directions to the source of radio emissions by maximizing the spatial power spectrum of the received signal. The advantage of the MUSiC algorithm over other popular DOA (direction of arrival) estimation methods is its effectiveness even in negative signal-to-noise ratios. The result of the research on the implemented setup is the determination of the azimuth to the radio tower in urban conditions. The research was carried out by analyzing the signal from an FM radio station at a frequency of 100.6 MHz. The error in determining the direction to the radio signal source was 6 degrees. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. A Novel Weighted Block Sparse DOA Estimation Based on Signal Subspace under Unknown Mutual Coupling.
- Author
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Liu, Yulong, Yin, Yingzeng, Lu, Hongmin, and Tong, Kuan
- Subjects
COVARIANCE matrices ,PROBLEM solving ,EIGENVALUES - Abstract
In this paper, a novel weighted block sparse method based on the signal subspace is proposed to realize the Direction-of-Arrival (DOA) estimation under unknown mutual coupling in the uniform linear array. Firstly, the signal subspace is obtained by decomposing the eigenvalues of the sampling covariance matrix. Then, a block sparse model is established based on the deformation of the product of the mutual coupling matrix and the steering vector. Secondly, a suitable set of weighted coefficients is calculated to enhance sparsity. Finally, the optimization problem is transformed into a second-order cone (SOC) problem and solved. Compared with other algorithms, the simulation results of this paper have better performance on DOA accuracy estimation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Dynamic Phase Comparison Planar Direction-Finding Algorithm on Satellite Radio Receiver.
- Author
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Wu, Zhongzhen, Mao, Mingyang, Xiong, Jiawei, Zhao, Ziyang, and Yuan, Kai
- Subjects
SATELLITE radio services ,ANTENNA arrays ,ANTENNAS (Electronics) ,ALGORITHMS ,DIPOLE antennas ,INTERFEROMETERS - Abstract
This paper proposes a dynamic phase comparison algorithm for planar direction finding on a high-speed moving satellite radio receiver, treating the moving antenna as equivalent to single-baseline array antennas. Based on a phase interferometer algorithm, this algorithm adjusts the baseline length according to the frequency measurement module and the satellite's high-speed motion to avoid phase ambiguity indirectly. By integrating the traditional amplitude comparison algorithm based on orthogonal dipole antennas, a dynamic fusion direction-finding method is proposed. Simulations demonstrate that this approach method not only covers a broader range of direction finding but also achieves higher accuracy, providing valuable insights for acquiring three-dimensional plasmagrams with space-borne plasma imagers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. An Improved Spatial Smoothing Technique Based on Cross-covariance for Coherent Signals DOA Estimation
- Author
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Qi, Bingbing, Xu, Lijun, and Liu, Xiaogang
- Published
- 2024
- Full Text
- View/download PDF
11. Design Approach and Comparison of Phase Shifter Performance in DOA Estimation System.
- Author
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Khedekar, Sachin R.
- Subjects
PHASED array antennas ,DIRECTION of arrival estimation ,PHASE shifters ,ANTENNA arrays ,CLOSED loop systems - Abstract
The paper outlines three types of phase shifter networks utilized in phased array antennas for direction-of-arrival estimation. It compares the mechanical rotation method of antenna array with Butler matrix-based and software-controlled phase shifter networks. Performance metrics such as phase shift accuracy and response time were considered. Comparisons were made between simulation and measurement results of Butler matrix and software-controlled networks. The mechanical rotation system operates as an open-loop system, while the other two can function as closed-loop systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Design of digital beamforming for 5G access point applications.
- Author
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Drissi, Meriem, Benjelloun, Nabil, Descamps, Philippe, and Gharsallah, Ali
- Subjects
- *
BEAMFORMING , *5G networks , *ADAPTIVE antennas , *ANTENNA arrays , *SOFTWARE radio - Abstract
Since the software‐defined radio digital beamforming (DBF) system is the newest tendency in fifth‐generation (5G) development and based on its flexibility applied to antenna arrays, this research paper presents a smart antenna array architecture operating in C‐band (3.48 GHz). In developing DBF for 5G access points with beamforming capacities, it is first necessary to perform an accurate approach that identifies the position of the desired user and affects the beamforming processing. In this article, a feasible approach is represented to evaluate and test three angle‐of‐arrival algorithms. To ensure the robustness of the system, the system structure with its four main components, the transmit subsystem, the synchronization subsystem, the receive subsystem, and data processing are described in detail. This article presents a reasonably inexpensive prototype DBF in conjunction with a Universal Software Radio Peripheral B210 board. Experimental measurements and results confirm the suggested methodology. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. Hereditary Optic Neuropathies: A Systematic Review on the Interplay between Biomaterials and Induced Pluripotent Stem Cells.
- Author
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Ladero, Miguel, Reche-Sainz, Jose Alberto, and Gallardo, M. Esther
- Subjects
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INDUCED pluripotent stem cells , *BIOMATERIALS , *RETINAL ganglion cells , *EXTRACELLULAR matrix , *DEGENERATION (Pathology) , *PLURIPOTENT stem cells - Abstract
Hereditary optic neuropathies (HONs) such as dominant optic atrophy (DOA) and Leber Hereditary Optic Neuropathy (LHON) are mitochondrial diseases characterized by a degenerative loss of retinal ganglion cells (RGCs) and are a cause of blindness worldwide. To date, there are only limited disease-modifying treatments for these disorders. The discovery of induced pluripotent stem cell (iPSC) technology has opened several promising opportunities in the field of HON research and the search for therapeutic approaches. This systematic review is focused on the two most frequent HONs (LHON and DOA) and on the recent studies related to the application of human iPSC technology in combination with biomaterials technology for their potential use in the development of RGC replacement therapies with the final aim of the improvement or even the restoration of the vision of HON patients. To this purpose, the combination of natural and synthetic biomaterials modified with peptides, neurotrophic factors, and other low- to medium-molecular weight compounds, mimicking the ocular extracellular matrices, with human iPSC or iPSC-derived cell retinal progenitors holds enormous potential to be exploited in the near future for the generation of transplantable RGC populations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
14. Implementación en FPGA de la Calibración de un Sistema de Antenas Inteligentes con Superresolución en la Estimación de DOA.
- Author
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Guerra, Yunior Ibarra, Ramírez, Noslen Rojas, Ramírez Zaldivar, Alexander R., and Violat, Abel Hernández
- Subjects
- *
ADAPTIVE antennas , *COMPUTER hardware description languages , *PDS (Computer system) , *FIELD programmable gate arrays , *DIRECTION of arrival estimation , *PROBLEM solving , *CALIBRATION - Abstract
Receiver channels amplitude and phase calibration in smart antennas is a crucial process to achieve the systems requirement. The implementation of these functions in a programmable device and the procedures for selecting its parameters is not a widely disseminated topic in the specialized literature. This work solves the previous problem by implementing the calibration algorithm in FPGA based on the requirements to guarantee the estimation of the direction of arrival (DOA) with super resolution. The design implemented in Hardware Description Language (HDL) corrects in real time the amplitude and phase errors between channels of the multichannel reception system with low latency and resource consumption. Experimental verification with real signals demonstrates that the errors obtained after calibration are within the expected range and corroborates the effectiveness of the design. [ABSTRACT FROM AUTHOR]
- Published
- 2024
15. Machine-Learning-Aided Massive Hybrid Analog and Digital MIMO DOA Estimation for Future Wireless Networks
- Author
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X. Zhao, B. Shi, J. Bai, F. Shu, Y. Chen, X. Zhan, W. Cai, M. Huang, Q. Jie, Y. Li, J. Wang, and X. You
- Subjects
doa ,hybrid analog and digital ,mimo ,green technologies ,crlb ,multi-layer-neural-network ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Due to a high spatial angle resolution and low circuit cost of massive hybrid analog and digital (HAD) multiple-input multiple-output (MIMO), it is viewed as a valuable green communication technology for future wireless networks. Integrating the massive HAD-MIMO with direction of arrival (DOA) will provide an even ultra-high performance of DOA measurement, which can the fully-digital (FD) MIMO. However, phase ambiguity is a challenge issue for a massive HAD-MIMO DOA estimation. In this paper, we consider three parts: detection, estimation, and Cramer-Rao lower bound (CRLB). First, a multi-layer-neural-network (MLNN) detector is proposed to infer the existence of emitters. Then, a two-layer HAD (TLHAD) MIMO structure is proposed to estimate the DOA and eliminate phase ambiguity using only one time block. Simulation results show that the proposed MLNN detector is much better than both the existing generalized likelihood ratio test (GRLT) and the ratio of maximum eigen-value (Max-EV) to minimum eigen-value (R-MaxEV-MinEV) in terms of detection probability. Additionally, the proposed TLHAD structure can achieve the corresponding CRLB.
- Published
- 2023
16. Off-Grid Underwater Acoustic Source Direction-of-Arrival Estimation Method Based on Iterative Empirical Mode Decomposition Interval Threshold
- Author
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Chuanxi Xing, Guangzhi Tan, and Saimeng Dong
- Subjects
hydrophone arrays ,DOA ,empirical mode decomposition ,Bayesian learning algorithm ,Chemical technology ,TP1-1185 - Abstract
To solve the problem that the hydrophone arrays are disturbed by ocean noise when collecting signals in shallow seas, resulting in reduced accuracy and resolution of target orientation estimation, a direction-of-arrival (DOA) estimation algorithm based on iterative EMD interval thresholding (EMD-IIT) and off-grid sparse Bayesian learning is proposed. Firstly, the noisy signal acquired by the hydrophone array is denoised by the EMD-IIT algorithm. Secondly, the singular value decomposition is performed on the denoised signal, and then an off-grid sparse reconstruction model is established. Finally, the maximum a posteriori probability of the target signal is obtained by the Bayesian learning algorithm, and the DOA estimate of the target is derived to achieve the orientation estimation of the target. Simulation analysis and sea trial data results show that the algorithm achieves a resolution probability of 100% at an azimuthal separation of 8° between adjacent signal sources. At a low signal-to-noise ratio of −9 dB, the resolution probability reaches 100%. Compared with the conventional MUSIC-like and OGSBI-SVD algorithms, this algorithm can effectively eliminate noise interference and provides better performance in terms of localization accuracy, algorithm runtime, and algorithm robustness.
- Published
- 2024
- Full Text
- View/download PDF
17. Machine-Learning-Aided Massive Hybrid Analog and Digital MIMO DOA Estimation for Future Wireless Networks.
- Author
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Xinyi ZHAO, Baihua SHI, Jiatong BAI, Feng SHU, Yiwen CHEN, Xichao ZHAN, Wenlong CAI, Mengxing HUANG, Qijuan JIE, Yifan LI, Jiangzhou WANG, and Xiaohu YOU
- Subjects
AMBIGUITY ,LIKELIHOOD ratio tests ,TELECOMMUNICATION ,SPATIAL resolution ,5G networks ,COMMUNICATION of technical information - Abstract
Due to a high spatial angle resolution and low circuit cost of massive hybrid analog and digital (HAD) multiple-input multiple-output (MIMO), it is viewed as a valuable green communication technology for future wireless networks. Integrating the massive HAD-MIMO with direction of arrival (DOA) will provide an even ultra-high performance of DOA measurement, which can the fullydigital (FD) MIMO. However, phase ambiguity is a challenge issue for a massive HAD-MIMO DOA estimation. In this paper, we consider three parts: detection, estimation, and Cramer-Rao lower bound (CRLB). First, a multi-layerneural-network (MLNN) detector is proposed to infer the existence of emitters. Then, a two-layer HAD (TLHAD) MIMO structure is proposed to estimate the DOA and eliminate phase ambiguity using only one time block. Simulation results show that the proposed MLNN detector is much better than both the existing generalized likelihood ratio test (GRLT) and the ratio of maximum eigen-value (Max-EV) to minimum eigen-value (R-MaxEV-MinEV) in terms of detection probability. Additionally, the proposed TLHAD structure can achieve the corresponding CRLB. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
18. DOA Estimation for Coherent Sources Based on Uniformly Distributed Two Concentric Rings Array.
- Author
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Han, Chuang, Guo, Shenghong, Yan, Ning, Dong, Jingwei, and Xing, Bowen
- Subjects
- *
COST functions , *FUNCTION spaces , *LOCALIZATION (Mathematics) , *ARRAY processing , *AUDIO frequency , *SIGNAL-to-noise ratio - Abstract
The direction estimation of the coherent source in a uniform circular array is an essential part of the signal processing area of the array, but the traditional uniform circular array algorithm has a low localization accuracy and a poor localization effect on the coherent source. To solve this problem, this paper proposes a two-dimensional direction of arrival (DOA) estimation for the coherent source in broadband. Firstly, the central frequency of the coherent sound source is estimated using the frequency estimation method of the delayed data, and a real-valued beamformer is constructed using the concept of the multiloop phase mode. Then, the cost function in the beam space is obtained. Finally, the cost function is searched in two dimensions to locate the sound source. In this paper, we simulate the DOA of the sound source at different frequencies and signal-to-noise ratios and analyze the resolution of the circular array. The simulation results show that the proposed algorithm can estimate the direction of arrival with high precision and achieve the desired results. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
19. An Enhanced DOA Estimation Method for Coherent Sources via Toeplitz Matrix Reconstruction and Khatri–Rao Subspace.
- Author
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Qi, Bingbing, Liu, Xiaogang, Dou, Daowei, Zhang, Yan, and Hu, Runze
- Subjects
TOEPLITZ matrices ,ACOUSTIC radiators ,DEGREES of freedom ,ARRAY processing - Abstract
The Toeplitz matrix reconstruction methods are capable of resolving coherent signals, playing a crucial role in the direction-of-arrival (DOA) estimation of acoustic sources. However, the decoherence processing sacrifices the array aperture and further results in a reduced resolution capability for the number of identifiable sources. To solve this issue, we propose an enhanced method using the Khatri–Rao subspace to resolve more coherent sources than that of the existing Toeplitz matrix reconstruction methods. Firstly, a full set of Toeplitz matrices with full rank is obtained. Then, the virtual array aperture can be obtained using the Khatri–Rao product of the array response, and the degree of freedom provided inherently in the virtual array structure is about twice the size of that of the existing Toeplitz methods. Next, linear processing is further used to achieve complexity reduction without losing the effective degree of freedom. Finally, the DOA estimation for more coherent sources can be achieved by combining it with conventional methods. Numerical simulations verify the superiority of the proposed method. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
20. Enhancement of Classifier Performance Using Swarm Intelligence in Detection of Diabetes from Pancreatic Microarray Gene Data.
- Author
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Chellappan, Dinesh and Rajaguru, Harikumar
- Subjects
- *
SWARM intelligence , *OPTIMIZATION algorithms , *DISCRETE cosine transforms , *METAHEURISTIC algorithms , *FEATURE selection , *GAUSSIAN mixture models - Abstract
In this study, we focused on using microarray gene data from pancreatic sources to detect diabetes mellitus. Dimensionality reduction (DR) techniques were used to reduce the dimensionally high microarray gene data. DR methods like the Bessel function, Discrete Cosine Transform (DCT), Least Squares Linear Regression (LSLR), and Artificial Algae Algorithm (AAA) are used. Subsequently, we applied meta-heuristic algorithms like the Dragonfly Optimization Algorithm (DOA) and Elephant Herding Optimization Algorithm (EHO) for feature selection. Classifiers such as Nonlinear Regression (NLR), Linear Regression (LR), Gaussian Mixture Model (GMM), Expectation Maximum (EM), Bayesian Linear Discriminant Classifier (BLDC), Logistic Regression (LoR), Softmax Discriminant Classifier (SDC), and Support Vector Machine (SVM) with three types of kernels, Linear, Polynomial, and Radial Basis Function (RBF), were utilized to detect diabetes. The classifier's performance was analyzed based on parameters like accuracy, F1 score, MCC, error rate, FM metric, and Kappa. Without feature selection, the SVM (RBF) classifier achieved a high accuracy of 90% using the AAA DR methods. The SVM (RBF) classifier using the AAA DR method for EHO feature selection outperformed the other classifiers with an accuracy of 95.714%. This improvement in the accuracy of the classifier's performance emphasizes the role of feature selection methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
21. Spatial–Temporal-Based 3-D Parameters Estimation Method for Near-Field Sources Using Parallel Factor Model.
- Author
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Wang, Weilong, Zhao, Tianyi, Dong, Hao, Zhu, Minghong, Zhou, Zheng, Chen, Hua, and Liu, Weiyue
- Subjects
- *
SIGNAL-to-noise ratio , *LEAST squares , *TIME delay estimation , *EIGENVALUES - Abstract
In this paper, a novel algorithm is presented for estimating three-dimensional (3-D) parameters of near-field (NF) sources with a centro-symmetric cross array, where the sub-array x and the sub-array y are uniform linear arrays equipped with the same number of array elements. By exploiting the time-delay-based spatial correlation of the received signal, the proper array elements are selected, respectively, from the two sub-arrays to define two sets of variables, and then two time-delay-based vectors are constructed. Further, a series of delay lags are uniformly sampled to form pseudo snapshots so as to obtain two corresponding time delay matrices, which facilitates the formation of the parallel factor (PARAFAC) model in time domain. Finally, trilinear alternating least squares decomposition is utilized to jointly estimate the two-dimensional (2-D) direction-of arrival and range parameters of NF sources from the PARAFAC model. In the case of low signal-to-noise ratio and small snapshots conditions, the estimation performance in the 3-D parameters of the proposed algorithm is superior to that of the subspace-based algorithm. In addition, the proposed algorithm only involves simple parameter pairing, which requires no eigenvalue decomposition and spectral peak searching. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
22. Pembentukan Kerohanian Reformed
- Author
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Audy Santoso
- Subjects
pujian ,doa ,antropologi ,John Calvin ,pembenaran ,trinitarian ,Christianity ,BR1-1725 - Abstract
Pembentukan Spiritual adalah subjek praktis di dalam kehidupan seorang Kristen yang sering kali tidak dipikirkan secara reflektif, jika bukan sepenuhnya diabaikan, bahkan bagi mereka yang di dalam tradisi Reformed. Artikel ini berargumen akan keunikan pembentukan rohani Kristen dari agama-agama Abrahamik lainnya berdasarkan argumen-argumen biblika dan fenomena sosial-agama. Reformasi berkontribusi terhadap pembentukan spiritual kristen berdasarkan pada prinsip-prinsip umumnya dan pemahaman antropologis Calvin. Artikel ini menyimpulkan bahwa pembentukan rohani Kristen tidak lain dari menghidupi kehidupan Tritunggal, yaitu dibentuk menyerupai Kristus dan dipenuhi Roh Kudus di dalam kehidupan kita sebagai anak-anak Allah.
- Published
- 2024
- Full Text
- View/download PDF
23. Performance Analysis of Smart Antenna in Wireless Communication System
- Author
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Mohapatra, Pradyumna Kumar, Rout, Saroja Kumar, Panda, Ravi Narayan, Gupta, N. Sujata, Swain, Nirmal Keshari, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Chaubey, Nirbhay, editor, Thampi, Sabu M., editor, Jhanjhi, Noor Zaman, editor, Parikh, Satyen, editor, and Amin, Kiran, editor
- Published
- 2023
- Full Text
- View/download PDF
24. A Novel Angle Measuring Method for 2D Digital Array Radars
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Chen, Anqi, Zhu, Yuzhu, Zhang, Haihui, Wu, Shiming, Liu, Xu, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Wang, Wei, editor, Liu, Xin, editor, Na, Zhenyu, editor, and Zhang, Baoju, editor
- Published
- 2023
- Full Text
- View/download PDF
25. A Robust DOA Estimation Method Based on Auxiliary Sensors and Power Inversion
- Author
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Song, Yihao, Huang, Puming, Qiu, Lede, Li, Shuai, Li, Ming, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Wang, Yue, editor, Liu, Yuyang, editor, Zou, Jiaqi, editor, and Huo, Mengyao, editor
- Published
- 2023
- Full Text
- View/download PDF
26. Comparative Study of DOA Estimation and Smart Antenna Beam Forming for Next-Generation Core Networks
- Author
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Thadikamalla, Nageswar Rao, Amara, Prakasa Rao, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, Rawat, Sanyog, editor, Kumar, Sandeep, editor, Kumar, Pramod, editor, and Anguera, Jaume, editor
- Published
- 2023
- Full Text
- View/download PDF
27. Derlin rhomboid pseudoproteases employ substrate engagement and lipid distortion to enable the retrotranslocation of ERAD membrane substrates
- Author
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Nejatfard, Anahita, Wauer, Nicholas, Bhaduri, Satarupa, Conn, Adam, Gourkanti, Saroj, Singh, Narinderbir, Kuo, Tiffany, Kandel, Rachel, Amaro, Rommie E, and Neal, Sonya E
- Subjects
Biochemistry and Cell Biology ,Biological Sciences ,Underpinning research ,1.1 Normal biological development and functioning ,Generic health relevance ,Endoplasmic Reticulum-Associated Degradation ,Lipid Metabolism ,Membrane Proteins ,Mutation ,Protein Binding ,Protein Interaction Domains and Motifs ,Protein Transport ,Saccharomyces cerevisiae ,Saccharomyces cerevisiae Proteins ,Valosin Containing Protein ,DOA ,Dfm1 ,ER ,ERAD ,HMG-CoA reductase ,HRD ,Hmg2 ,derlins ,retrotranslocation ,rhomboid pseudoprotease ,Endoplasmic Reticulum ,Medical Physiology ,Biological sciences - Abstract
Nearly one-third of proteins are initially targeted to the endoplasmic reticulum (ER) membrane, where they are correctly folded and then delivered to their final cellular destinations. To prevent the accumulation of misfolded membrane proteins, ER-associated degradation (ERAD) moves these clients from the ER membrane to the cytosol, a process known as retrotranslocation. Our recent work in Saccharomyces cerevisiae reveals a derlin rhomboid pseudoprotease, Dfm1, is involved in the retrotranslocation of ubiquitinated ERAD membrane substrates. In this study, we identify conserved residues of Dfm1 that are critical for retrotranslocation. We find several retrotranslocation-deficient Loop 1 mutants that display impaired binding to membrane substrates. Furthermore, Dfm1 possesses lipid thinning function to facilitate in the removal of ER membrane substrates, and this feature is conserved in its human homolog, Derlin-1, further implicating that derlin-mediated retrotranslocation is a well-conserved process.
- Published
- 2021
28. Analysis of the Broiler Chicken Dead-on-Arrival (DOA) Rate in Relation to Normal Transport Conditions in Practice in Germany
- Author
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Julia Gickel, Christian Visscher, Nicole Kemper, and Birgit Spindler
- Subjects
slaughterhouse ,broiler ,transport ,DOA ,influencing factors ,duration ,Veterinary medicine ,SF600-1100 ,Zoology ,QL1-991 - Abstract
In total, around 631 million broilers were slaughtered in Germany in 2022. This evaluation included data of approx. 198 million broilers of different ages and breeds that were transported in Germany in 2022 (31% of all cases of broiler chicken transport in 2022). The aim of this study was to analyze German broiler chicken transport (n = 14,054) to the slaughterhouse between January 2022 and May 2023 with regard to the dead-on-arrival (DOA) rate and the possible influencing factors. Therefore, the relation between the total amount of animals per transport, the duration and distance of the transport, the planned stocking density in the transport cages, the average daily temperature and time of day and season of the transport as well as the DOA rate were statistically evaluated. The results showed a mean DOA rate of 0.09% (SD 0.09). Transport conducted at midday (11:00 to 17:00) showed higher DOA rates (p < 0.05) than transport at other times (day split into 6 h intervals). The highest mean DOA rate (0.10%) was found in the fall, followed by the winter, while transport in the spring and summer resulted in the lowest DOA rate (p < 0.05). All in all, the relatively low DOA rate (%) in Germany indicates the good standard of their broiler transport compared to available data from research in other European countries.
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- 2024
- Full Text
- View/download PDF
29. Spatial Spectrum Estimation of Weak Scattering Wave Signal in Range-Doppler Domain
- Author
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Hang Xu, Hong Ma, Li Wang, Jiang Jin, Hua Zhang, and Xiaodong Liu
- Subjects
UCA ,DOA ,spatial spectrum estimation ,Range-Doppler ,SNR gain ,coherent signals ,Science - Abstract
How to enhance the desired signal with low signal-to-noise ratio (SNR) is a difficult problem in the estimation process of the direction-of-arrival (DOA) of the target scattering wave signal. In this paper, the feasibility of spatial spectrum estimation in the Range-Doppler (RD) domain is analyzed in principle, and the SNR gain expression of weak scattering wave signal is derived when constructing multi-snapshots virtual array data. On this basis, the mutual eigenvector singular value decomposition (MESVD) method based on RD domain mode excitation is proposed, which can robustly and effectively estimate the direction of the coherent weak signals. Simulation experiments verify that the RD domain spectral estimation method has the ability to simultaneously obtain the direction of multiple weak target scattering waves, and the direction-finding accuracy can reach the Cramer–Rao bound (CRB) of conventional spectral estimation method. The results of Monte Carlo experiments show that the root-mean-square-error (RMSE) of azimuth estimation of RD domain spatial spectrum estimation method is 5.76° lower than that of a conventional multiple signal classification (MUSIC) method. In addition, the practicability of the proposed method is demonstrated by comparing the DOA estimation results of a set of real data with Automatic Dependent Surveillance-Broadcast (ADS-B) data.
- Published
- 2024
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- View/download PDF
30. Dynamic Phase Comparison Planar Direction-Finding Algorithm on Satellite Radio Receiver
- Author
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Zhongzhen Wu, Mingyang Mao, Jiawei Xiong, Ziyang Zhao, and Kai Yuan
- Subjects
direction finding ,interferometer ,DOA ,amplitude comparison ,RPI ,dipole antenna ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This paper proposes a dynamic phase comparison algorithm for planar direction finding on a high-speed moving satellite radio receiver, treating the moving antenna as equivalent to single-baseline array antennas. Based on a phase interferometer algorithm, this algorithm adjusts the baseline length according to the frequency measurement module and the satellite’s high-speed motion to avoid phase ambiguity indirectly. By integrating the traditional amplitude comparison algorithm based on orthogonal dipole antennas, a dynamic fusion direction-finding method is proposed. Simulations demonstrate that this approach method not only covers a broader range of direction finding but also achieves higher accuracy, providing valuable insights for acquiring three-dimensional plasmagrams with space-borne plasma imagers.
- Published
- 2024
- Full Text
- View/download PDF
31. Causes of carcass condemnation in Norwegian aviary housed layers
- Author
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Páll Gretarsson, Käthe Kittelsen, Randi Oppermann Moe, and Ingrid Toftaker
- Subjects
Animal welfare ,Carcass rejection ,DOA ,Laying hen ,Meat inspection ,Poultry health ,Veterinary medicine ,SF600-1100 - Abstract
Abstract Background Meat inspection data is commonly used to monitor health and welfare in commercial broiler production; however, less used in layers. Slaughterhouse records can provide insight into animal and herd health and identify important health and welfare challenges. To gain knowledge of health issues in commercial aviary housed laying hens, the aim of this repeated cross-sectional study was to describe the occurrence and causes of carcass condemnation, including dead-on-arrivals (DOA), in commercial aviary housed layers in Norway, and to explore seasonal patterns and correlation between DOA and number of carcass condemnations. Results Data from January 2018 to December 2020 were collected from one poultry abattoir in Norway. In total, 759,584 layers were slaughtered during this period in 101 slaughter batches from 98 flocks and 56 farms. In total, 33,754 (4.4%) layers were condemned, including the DOA. The most common carcass condemnation causes were (percent of all slaughtered layers): abscess/cellulitis (2.03%), peritonitis (0.38%), DOA (0.22%), emaciation (0.22%), discoloration/smell (0.21%), acute skin lesions (0.21%) and ascites (0.17%). Regression analysis showed an estimated higher prevalence of total carcass condemnation during winter compared to the other seasons. Conclusions The three most common condemnation causes found in the present study were: abscess/cellulitis, peritonitis, and DOA. We found a large between-batch variation in causes of condemnation and DOA indicating that prevention might be possible. The results can be used to inform and guide further studies on layer health and welfare.
- Published
- 2023
- Full Text
- View/download PDF
32. Towards localisation in next-generation wireless systems
- Author
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Chitambira, Benny, Armour, Simon, and Beach, Mark
- Subjects
621.384 ,Localisation ,5G ,MIMO ,Support vector machine ,TDOA ,DOA - Abstract
Localisation in wireless communication systems is an important topic that has many applications. Accurate geolocation in urban environments is a well understood challenge and Global Navigation Satellite System (GNSS) based technologies like GPS yield poor accuracy in non-line-of-sight (NLOS) scenarios. Use of multiple GNSS systems improves location accuracy but is still affected by urban canyons. Mobile network-based schemes offer an alternative, particularly when antenna arrays are deployed. Massive antenna arrays in Massive Multiple-Input-Multiple-Output (Massive MIMO) present an opportunity because of the possibility to use inexpensive, low-power and low-precision components with greatly reduced complexity/cost, in addition to Massive MIMO being a core component of 5G. This thesis reviews the problem of localisation in urban environments and investigates the techniques that are relevant towards achieving localisation in next generation wireless systems. It evaluates the NLOS problem and proposes schemes that use machine leaning techniques in the form of Least-Squares Support Vector Machines (LSSVMs), to address the challenges. It also investigates Direction of Arrival (DOA) estimation, which is a step towards localisation, using the Bristol Massive MIMO testbed. The proposed location specific approach presented in this thesis is a new framework which is shown to achieve a best case NLOS identification accuracy of greater than 98 percent. This result exceeds reported accuracies for existing NLOS identification techniques. Another proposed direct localisation approach achieves an 80th percentile probability location accuracy of 10 metres without utilising NLOS identification and mitigation. DOA estimation experiments demonstrate the possibility of performing estimation using subsets of antennas on a single base station antenna array. An outdoor experiment demonstrated a best case DOA RMSE of 2 degrees achieved for 3 different User Equipment (UE) positions. Overall, the results in this thesis demonstrate techniques that can be employed to solve the intermediate challenges towards device localisation and can contribute to the design and operation of next-generation systems. Significant benefits for mobile wireless systems can be derived from localisation. New handover strategies, new dynamic resource, power and pilot allocation schemes that take advantage of the location information, can also be developed.
- Published
- 2021
33. Establishing induced pluripotent stem cell lines from two dominant optic atrophy patients with distinct OPA1 mutations and clinical pathologies.
- Author
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Pohl, Katherine A., Xiangmei Zhang, Pham, Anh H., Chan, Jane W., Sadun, Alfredo A., and Xian-Jie Yang
- Subjects
RETINAL ganglion cells ,PLURIPOTENT stem cells ,CYTOLOGY ,CLINICAL pathology ,ATROPHY ,CELL lines - Abstract
Dominant optic atrophy (DOA) is an inherited disease that leads to the loss of retinal ganglion cells (RGCs), the projection neurons that relay visual information from the retina to the brain through the optic nerve. The majority of DOA cases can be attributed to mutations in optic atrophy 1 (OPA1), a nuclear gene encoding a mitochondrial-targeted protein that plays important roles in maintaining mitochondrial structure, dynamics, and bioenergetics. Although OPA1 is ubiquitously expressed in all human tissues, RGCs appear to be the primary cell type affected by OPA1 mutations. DOA has not been extensively studied in human RGCs due to the general unavailability of retinal tissues. However, recent advances in stem cell biology have made it possible to produce human RGCs from pluripotent stem cells (PSCs). To aid in establishing DOA disease models based on human PSC-derived RGCs, we have generated iPSC lines from two DOA patients who carry distinct OPA1 mutations and present very different disease symptoms. Studies using these OPA1 mutant RGCs can be correlated with clinical features in the patients to provide insights into DOA disease mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Satellite Interference Source Direction of Arrival (DOA) Estimation Based on Frequency Domain Covariance Matrix Reconstruction.
- Author
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Yao, Jinjie, Zhao, Changchun, Bai, Jiansheng, Ren, Yang, Wang, Yangyang, and Miao, Jing
- Subjects
- *
COVARIANCE matrices , *SIGNAL-to-noise ratio , *FAST Fourier transforms , *ARTIFICIAL satellites in navigation , *SATELLITE positioning , *SPACE debris - Abstract
Direction of arrival (DOA) estimation is an effective method for detecting various active interference signals during the satellite navigation process. It can be utilized for both interference detection and anti-interference applications. This paper proposes a DOA estimation algorithm for satellite interference sources based on frequency domain covariance matrix reconstruction (FDCMR) to address various types of active interference that may occur in the satellite navigation positioning process. This algorithm can estimate the DOA of coherent signals from multiple frequency points under low signal-to-noise ratio (SNR) conditions. The signals received from the array are transformed from the time domain to the frequency domain using a fast Fourier transform (FFT). The data corresponding to the frequency point of the target signal is extracted from the signal in the frequency domain. The frequency domain covariance matrix of the received array signals is reconstructed by utilizing its covariance matrix property. The spatial spectrum search method is used for the final DOA estimation. Simulation experiments have shown that the proposed algorithm performs well in the DOA estimation under low SNR conditions and also resolves coherency. Moreover, the algorithm's effectiveness is verified through comparison with three other algorithms. Finally, the algorithm's applicability is validated through simulations of various interference scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
35. Low-Complexity Beamspace DOA Estimation for Coherently Distributed Sources in Massive MIMO Systems.
- Author
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He, Xin, Liu, Yang, Jia, Zifan, Wu, Huijuan, Zhang, Yinghui, and Qiu, Tianshuang
- Subjects
- *
MIMO radar , *MIMO systems , *COVARIANCE matrices , *MATRIX decomposition , *TELECOMMUNICATION systems , *ANTENNAS (Electronics) , *PARAMETER estimation - Abstract
Coherently Distributed (CD) sources are suitable for practical direction-of-arrival (DOA) estimation in massive Multiple-Input Multiple-Output (MIMO) communication systems. However, massive MIMO systems employ a large number of antennas to improve performance, which significantly raises the complexity of conventional DOA estimation algorithms for CD sources. To reduce the complexity, a novel low-complexity CD unitary estimation of signal parameters via the rotational invariance technique (U-ESPRIT) algorithm based on discrete cosine transformation (DCT) beamspace transformation and multistage Wiener filter (BU-ESPRIT) is proposed in this paper. To concentrate the signal energy and make better use of beamspace features, the DCT transformation is used to extract the signal. For the sake of reducing the complexity and achieving accurate angle estimation, U-ESPRIT is performed in beamspace. Moreover, the covariance matrix matching process and eigenvalue decomposition of the covariance matrix are substituted by forward recursion of the multistage Wiener filter to further reduce the complexity of the proposed algorithm. Theoretical analysis indicates the computational superiority of the proposed algorithm over that of some existing algorithms. Simulation results demonstrate that the proposed algorithm can be utilized to efficiently estimate angles of CD sources in massive MIMO systems. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
36. An Improved Two-Stage Spherical Harmonic ESPRIT-Type Algorithm.
- Author
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Zhou, Haocheng, Liu, Zhenghong, Luo, Liyan, Wang, Mei, and Song, Xiyu
- Subjects
- *
SOUND pressure , *ACOUSTIC field , *SENSOR arrays , *MICROPHONE arrays , *ANGLES , *ROTATIONAL symmetry , *AZIMUTH - Abstract
Sensor arrays are gradually becoming a current research hotspot due to their flexible beam control, high signal gain, robustness against extreme interference, and high spatial resolution. Among them, spherical microphone arrays with complex rotational symmetry can capture more sound field information than planar arrays and can convert the collected multiple speech signals into the spherical harmonic domain for processing through spherical modal decomposition. The subspace class direction of arrival (DOA) estimation algorithm is sensitive to noise and reverberation, and its performance can be improved by introducing relative sound pressure and frequency-smoothing techniques. The introduction of the relative sound pressure can increase the difference between the eigenvalues corresponding to the signal subspace and the noise subspace, which is helpful to estimate the number of active sound sources. The eigenbeam estimation of signal parameters via the rotational invariance technique (EB-ESPRIT) is a well-known subspace-based algorithm for a spherical microphone array. The EB-ESPRIT cannot estimate the DOA when the elevation angle approaches 90°. Huang et al. proposed a two-step ESPRIT (TS-ESPRIT) algorithm to solve this problem. The TS-ESPRIT algorithm estimates the elevation and azimuth angles of the signal independently, so there is a problem with DOA parameter pairing. In this paper, the DOA parameter pairing problem of the TS-ESPRIT algorithm is solved by introducing generalized eigenvalue decomposition without increasing the computation of the algorithm. At the same time, the estimation of the elevation angle is given by the arctan function, which increases the estimation accuracy of the elevation angle of the algorithm. The robustness of the algorithm in a noisy environment is also enhanced by introducing the relative sound pressure into the algorithm. Finally, the simulation and field-testing results show that the proposed method not only solves the problem of DOA parameter pairing, but also outperforms the traditional methods in DOA estimation accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
37. Analysis and Design of a MuSiC-Based Angle of Arrival Positioning System.
- Author
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GUNIA, MARCO, ZINKE, ADRIAN, JORAM, NIKO, and ELLINGER, FRANK
- Subjects
MULTIPLE Signal Classification ,COMPUTER firmware ,ANGLES ,ANTENNAS (Electronics) ,FAST Fourier transforms - Abstract
In this research article, a concept for a secondary RAdio Direction And Ranging (RADAR) angle of arrival based system with cooperative targets transmitting at 2.4 GHz and using Multiple Signal Classification (MuSiC) to determine the angles of incidence is investigated. In addition to introducing common algorithms and presenting thorough derivations, the system is first examined through simulations. To prove the concept, hardware, firmware, and software are developed. For MuSiC, we propose three novel methods to obtain the correct incident angle from the spectrum, especially in strong multipath environments. These methods work either for a single spectrum or for a combination recorded at multiple times. Together with the estimated angles of incidence, our methods determine measures on the respective likelihoods. Based on this, we additionally propose two algorithms for computing the final position. Our system is characterized in both a simple 20 m × 15 m outdoor and a 17 m × 13 m multipath indoor environment, where we achieve a mean angular error of 3◦ and a mean positioning error of 0.67 m for the former using only four base stations with four antennas each. Our novel approach shows position accuracy improvements of 15% outdoors and 25% indoors compared to classical MuSiC estimation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. 催化裂化油浆与脱油沥青调和制备 重交沥青及其SBS改性研究.
- Author
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梁明, 焦月朋, 辛雪, 仇正梅, 栾学昊, 张云风, and 汪健江
- Abstract
Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
39. Waveform Design and DoA-DoD Estimation of OFDM-LFM Signal Based on SDFnT for MIMO Radar
- Author
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Jingqi Wang, Pingping Wang, Fan Luo, and Wen Wu
- Subjects
MIMO radar ,MUSIC ,DoA ,DoD ,SDFnT ,OFDM-LFM ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
In comparison to orthogonal frequency division multiplexing (OFDM), the OFDM linear frequency modulation (OFDM-LFM) signal has similar time-bandwidth product, lower peak-to-average power ratio, and higher sensitivity to Doppler frequency shift, making it a promising candidate waveform for multiple-in multiple-out (MIMO) radar applications. However, the OFDM-LFM signal is unsatisfactory in practical applications due to the challenges in waveform design and its non-stationary property, which significantly degrades the performance of current high-resolution subspace techniques for direction of departure (DoD) and direction of arrival (DoA) angle estimation. In this paper, we first proposed a novel OFDM-LFM waveform design method based on the scale discrete Fresnel transform (SDFnT), which efficiently generates orthogonal LFM signals with unlimited number of subcarriers and can be convieniently implemented using the fast Fourier transform (FFT). Then, for angle estimation in OFDM-LFM MIMO radars, we presented a new scale discrete Fresnel transform multiple signal classification (SDFnT-MUSIC) method. By converting the steering vector into the chirp domain and making it non-time-vary, high resolution angle estimation for OFDM-LFM wideband signals can be achieved. Simulation results shows that the proposed waveform design method requires less computational time than conventional method based based on the fractional Fourier transform (FrFT), whereas the proposed DoA-DoD estimation method outperform the FrFT-MUSIC method in terms of computational complexity and target angle estimate performance.
- Published
- 2023
- Full Text
- View/download PDF
40. Establishing induced pluripotent stem cell lines from two dominant optic atrophy patients with distinct OPA1 mutations and clinical pathologies
- Author
-
Katherine A. Pohl, Xiangmei Zhang, Anh H. Pham, Jane W. Chan, Alfredo A. Sadun, and Xian-Jie Yang
- Subjects
dominant optic atrophy ,DOA ,OPA1 ,induced pluripotent stem cells (iPSC) ,retinal ganglion cell ,RGC ,Genetics ,QH426-470 - Abstract
Dominant optic atrophy (DOA) is an inherited disease that leads to the loss of retinal ganglion cells (RGCs), the projection neurons that relay visual information from the retina to the brain through the optic nerve. The majority of DOA cases can be attributed to mutations in optic atrophy 1 (OPA1), a nuclear gene encoding a mitochondrial-targeted protein that plays important roles in maintaining mitochondrial structure, dynamics, and bioenergetics. Although OPA1 is ubiquitously expressed in all human tissues, RGCs appear to be the primary cell type affected by OPA1 mutations. DOA has not been extensively studied in human RGCs due to the general unavailability of retinal tissues. However, recent advances in stem cell biology have made it possible to produce human RGCs from pluripotent stem cells (PSCs). To aid in establishing DOA disease models based on human PSC-derived RGCs, we have generated iPSC lines from two DOA patients who carry distinct OPA1 mutations and present very different disease symptoms. Studies using these OPA1 mutant RGCs can be correlated with clinical features in the patients to provide insights into DOA disease mechanisms.
- Published
- 2023
- Full Text
- View/download PDF
41. A GNSS Spoofing Detection and Direction-Finding Method Based on Low-Cost Commercial Board Components.
- Author
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Mao, Pengrui, Yuan, Hong, Chen, Xiao, Gong, Yingkui, Li, Shuhui, Li, Ran, Luo, Ruidan, Zhao, Guangyao, Fu, Chengang, and Xu, Jiajia
- Subjects
- *
ANTENNAS (Electronics) - Abstract
The Global Navigation Satellite System (GNSS) is vulnerable to deliberate spoofing signal attacks. Once the user wrongly locks on the spoofing signal, the wrong position, velocity, and time (PVT) information will be calculated, which will harm the user. GNSS spoofing signals are difficult to carry out spoofing attacks in the direction of arrival (DOA) of the real signal, so the spoofing detection method based on DOA is very effective. On the basis of identifying spoofing signals, accurate DOA information of the signal can be further used to locate the spoofer. At present, the existing DOA monitoring methods for spoofing signals are mainly based on dedicated antenna arrays and receivers, which are costly and difficult to upgrade and are not conducive to large-scale deployment, upgrade, and maintenance. This paper proposes a spoofing detection and direction-finding method based on a low-cost commercial GNSS board component (including an antenna). Based on the traditional principle of using a multi-antenna carrier phase to solve DOA, this paper innovatively solves the following problems: the poor direction-finding accuracy caused by the unstable phase center of low-cost commercial antennas, the low success rate of spoofing detection in a multipath environment, and the inconsistent sampling time among multiple low-cost commercial GNSS boards. Moreover, the corresponding prototype equipment for spoofing detection and direction-finding is developed. The measured results show that it can effectively detect spoofing signals in open environments. Under a certain false alarm rate, the detection success rate can reach 100%, and the typical direction-finding accuracy can reach 5 ° . [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
42. An Optimal Shaped Sensor Array Derivation.
- Author
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Dibiase, Marco and De Marchi, Luca
- Subjects
TRANSDUCERS ,GREEN'S functions ,STRUCTURAL health monitoring ,SENSOR arrays ,ACOUSTIC radiators ,SPATIAL filters ,THEORY of wave motion - Abstract
In Structural Health Monitoring (SHM) applications, the Direction of Arrival (DoA) estimation of Guided Waves (GW) on sensor arrays is often used as a fundamental means to locate Acoustic Sources (AS) generated by damages growth or undesired impacts in thin-wall structures (e.g., plates or shells). In this paper, we consider the problem of designing the arrangement and shape of piezo-sensors in planar clusters in order to optimize the DoA estimation performance in noise-affected measurements. We assume that: (i) the wave propagation velocity is unknown, (ii) the DoA is estimated via the time delays of wavefronts between sensors, and (iii) the maximum value of the time delays is limited. The optimality criterion is derived basing on the Theory of Measurements. The sensor array design is so that the DoA variance is minimized in an average sense by exploiting the Calculus of Variations. In this way, considering a three-sensor cluster and a monitored angles sector of 90°, the optimal time delays–DoA relations are derived. A suitable re-shaping procedure is used to impose such relations and, at the same time, to induce the same spatial filtering effect between sensors so that the sensor acquired signals are equal except for a time-shift. In order to achieve the last aim, the sensors shape is realized by exploiting a technique called Error Diffusion, which is able to emulate piezo-load functions with continuously modulated values. In this way, the Shaped Sensors Optimal Cluster (SS-OC) is derived. A numerical assessment via Green's functions simulations shows improved performance in DoA estimation by means of the SS-OC when compared to clusters realized with conventional piezo-disk transducers. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Causes of carcass condemnation in Norwegian aviary housed layers.
- Author
-
Gretarsson, Páll, Kittelsen, Käthe, Oppermann Moe, Randi, and Toftaker, Ingrid
- Subjects
- *
AVIARIES , *HENS , *ANIMAL herds , *HEALTH literacy , *ANIMAL health , *EGG quality , *MEAT inspection - Abstract
Background: Meat inspection data is commonly used to monitor health and welfare in commercial broiler production; however, less used in layers. Slaughterhouse records can provide insight into animal and herd health and identify important health and welfare challenges. To gain knowledge of health issues in commercial aviary housed laying hens, the aim of this repeated cross-sectional study was to describe the occurrence and causes of carcass condemnation, including dead-on-arrivals (DOA), in commercial aviary housed layers in Norway, and to explore seasonal patterns and correlation between DOA and number of carcass condemnations. Results: Data from January 2018 to December 2020 were collected from one poultry abattoir in Norway. In total, 759,584 layers were slaughtered during this period in 101 slaughter batches from 98 flocks and 56 farms. In total, 33,754 (4.4%) layers were condemned, including the DOA. The most common carcass condemnation causes were (percent of all slaughtered layers): abscess/cellulitis (2.03%), peritonitis (0.38%), DOA (0.22%), emaciation (0.22%), discoloration/smell (0.21%), acute skin lesions (0.21%) and ascites (0.17%). Regression analysis showed an estimated higher prevalence of total carcass condemnation during winter compared to the other seasons. Conclusions: The three most common condemnation causes found in the present study were: abscess/cellulitis, peritonitis, and DOA. We found a large between-batch variation in causes of condemnation and DOA indicating that prevention might be possible. The results can be used to inform and guide further studies on layer health and welfare. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
44. Improved Adaptive Beamforming Algorithms for Wireless Systems.
- Author
-
Dakulagi, Veerendra
- Subjects
BEAMFORMING ,TELECOMMUNICATION systems ,ALGORITHMS ,TOEPLITZ matrices ,SIGNAL-to-noise ratio - Abstract
The classical least mean square (LMS) algorithm is a widely studied method for adaptive beamforming. It is well known for its lower computational complexity. However, fast and robust beamforming is not possible with the classical LMS method since it uses a constant step size. This nature hinders its applications in many advanced communication systems. Furthermore, this method degrades when the signal-to-noise ratio is rapidly changing. To circumvent these issues posed by the classical LMS method, two modified LMS beamformers are presented in this paper. We name these methods as M-LMS-1 and M-LMS-2. We present two new complex array weights to accelerate the rate of convergence. Computer simulations show that both methods present fast and robust beamforming. That is these algorithms have convergence improvement of about 37.5 % and 50 % over the standard LMS algorithm. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
45. DOA Based Identification for Devices and Applications of IoT in Heterogeneous Networks
- Author
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Al-Bahri, Mahmood, Al Kishri, Wasan, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Daimi, Kevin, editor, and Al Sadoon, Abeer, editor
- Published
- 2022
- Full Text
- View/download PDF
46. Effective DOA Estimation Method for Sound Source Localization Using a Circular Microphone Array
- Author
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Belgacem, Douaer, Kacprzyk, Janusz, Series Editor, Gomide, Fernando, Advisory Editor, Kaynak, Okyay, Advisory Editor, Liu, Derong, Advisory Editor, Pedrycz, Witold, Advisory Editor, Polycarpou, Marios M., Advisory Editor, Rudas, Imre J., Advisory Editor, Wang, Jun, Advisory Editor, and Hatti, Mustapha, editor
- Published
- 2022
- Full Text
- View/download PDF
47. A Comprehensive Analysis of the Impact of System Parameters on Subspace-based DoA Estimation Performance
- Author
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Bakhtiar A. Karim and Haitham K. Ali
- Subjects
doa ,subspace ,music ,estimation ,computational-complexity ,resolution ,Technology ,Science - Abstract
This work provides an explanatory analysis of the influence of input parameters on the performance of subspace-based Direction of Arrival (DoA) estimation algorithms. The objective of this work is twofold. First, to drive a Steering Vector (SV) that works for arbitrary array configuration rather than just Uniform Linear Array (ULA) geometry. Second, to identify how the performance of the subspace-based algorithms is affected by tuning the input parameters. The later objective is crucial as it allows optimizing the algorithm through selecting optimum parameters to set an appropriate tradeoff between complexity and performance based on the intended applications. Toward that end, we firstly drive an SV for arbitrary array configuration followed by revealing the working principle of subspace based DoA techniques. Secondly, we evaluate the impact of several parameters namely Signal to Noise Ratio (SNR), number of snapshots, number of array elements, separation between array elements, number of available sources, and dependency between sources to conduct our analysis. Numerical simulations over a wide range of scenarios along with intensive Monte Carlo simulations are conducted to show the influence of these parameters on the resolution, accuracy, and complexity of the subspace based DoA estimation algorithm. As demonstrated by the obtained results, the performance of this class of DoA estimation method is determined mostly by the values of the input parameters. Furthermore, the simulation results show that tradeoff between performance and computational complexity needs to be considered when the system parameters are chosen for DoA estimation algorithms.
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- 2022
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48. 数据空间基础设施的技术挑战及 数联网解决方案.
- Author
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罗超然, 马郓, 景翔, and 黄罡
- Abstract
Dataspace is the transformation of cyberspace from "computing centric" to "data centric", which contains great technological issues and innovative opportunities. Similar to the internet, which is the main infrastructure of cyberspace, dataspace also needs a new "data-centric" infrastructure, whose core function is to realize the first-class entity of data. From the perspective of dataspace, the supports and shortcomings of mainstream technologies such as the internet, the World Wide Web, and the digital object architecture for the first-class entity of data were analyzed and summarized, and then the basic connotations and technical challenges of dataspace infrastructure were given. Finally, a first-class data substantialization method based on data pragmatics was proposed. Based on this method, a solution called the internet of data by integrating digital object architecture, distributed ledger, smart contract, and other technologies was proposed to support the construction and operation of internetscale dataspace infrastructure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
49. 基于神经网络的相干信源稳健DOA估计.
- Author
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钟东强, 何培宇, and 喻伟闯
- Subjects
MULTIPLE Signal Classification ,COVARIANCE matrices ,SIGNAL-to-noise ratio ,SIGNALS & signaling ,ANGLES - Abstract
Copyright of Journal Of Sichuan University (Natural Sciences Division) / Sichuan Daxue Xuebao-Ziran Kexueban is the property of Editorial Department of Journal of Sichuan University Natural Science Edition and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
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50. Acoustic Vector Sensor Multi-Source Detection Based on Multimodal Fusion.
- Author
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Chen, Yang, Zhang, Guangyuan, Wang, Rui, Rong, Hailong, and Yang, Biao
- Subjects
- *
MULTIMODAL user interfaces , *DETECTORS , *FOURIER transforms , *PROBLEM solving , *HILBERT-Huang transform - Abstract
The direction of arrival (DOA) and number of sound sources is usually estimated by short-time Fourier transform and the conjugate cross-spectrum. However, the ability of a single AVS to distinguish between multiple sources will decrease as the number of sources increases. To solve this problem, this paper presents a multimodal fusion method based on a single acoustic vector sensor (AVS). First, the output of the AVS is decomposed into multiple modes by intrinsic time-scale decomposition (ITD). The number of sources in each mode decreases after decomposition. Then, the DOAs and source number in each mode are estimated by density peak clustering (DPC). Finally, the density-based spatial clustering of applications with the noise (DBSCAN) algorithm is employed to obtain the final source counting results from the DOAs of all modes. Experiments showed that the multimodal fusion method could significantly improve the ability of a single AVS to distinguish multiple sources when compared to methods without multimodal fusion. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
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