Journal articles: 'Array'

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Abdellatif, Ahmed Shehata, Wenyao Zhai, Hari Krishna Pothula, and Morris Repeta. "Array of Arrays: Optimizing Phased Array Tiles." IEEE Antennas and Wireless Propagation Letters 20, no. 5 (May 2021): 718–22. http://dx.doi.org/10.1109/lawp.2021.3061281.

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Weitzman, Jonathan B. "Array-of-arrays." Genome Biology 2 (2001): spotlight—20010201–01. http://dx.doi.org/10.1186/gb-spotlight-20010201-01.

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Mukit, Naimul, Md Rafiqul Islam, Mohamed Hadi Habaebi, A. H. M. Zahirul Alam, Khaizuran Abdullah, Norun Farihah Abdul Malek, Rauful Nibir, Noor Hidayah M. Adnan, and Eid Osman. "Designing large-scale antenna array using sub-array." Bulletin of Electrical Engineering and Informatics 8, no. 3 (September 1, 2019): 906–15. http://dx.doi.org/10.11591/eei.v8i3.1529.

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Antenna array of large scale have been examined for different applications including 5G technology. To get better data rate or a reliable link substantial number of antenna arrays have been utilized to provide high multiplexing gains as well as array gains with high directivity. In this paper a simple but efficient implementation technique of using sub-arrays for the improvement of large-sized uniform arrays. By repeating a small sub-array multiple times large arrays can be designed. This implication of utilizing small array simplifies the design of a larger array which allows the designer to concentrate on the smaller sub-array before assembling larger arrays. So, by investigating the sub arrays the performance and radiation characteristics of large arrays can be anticipated. The array-factor for a planar sub-array of 2x2 (4 elements) is analyzed using Mat-lab software and then a large array is formed by placing the 2x2 sub-array indifferent configurations in a rectangular arrangements up to 8x8 planar array. And then the results are validated with CST (Computer simulation technology) simulation results.In this way the array-factors, directivities, HPBWs, and side lobes of the constructed large arrays are analyzed and associated with the small sub-array.

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Mervis, J. "An Array of Arrays." Science 275, no. 5298 (January 17, 1997): 300. http://dx.doi.org/10.1126/science.275.5298.300b.

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Micheva, K. D., N. O'Rourke, B. Busse, and S. J. Smith. "Array Tomography: Production of Arrays." Cold Spring Harbor Protocols 2010, no. 11 (November 1, 2010): pdb.prot5524. http://dx.doi.org/10.1101/pdb.prot5524.

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Micheva, K. D., N. O'Rourke, B. Busse, and S. J. Smith. "Array Tomography: Imaging Stained Arrays." Cold Spring Harbor Protocols 2010, no. 11 (November 1, 2010): pdb.prot5526. http://dx.doi.org/10.1101/pdb.prot5526.

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Yang, T. C., and Zhengzheng Ye. "Array gain of coprime arrays." Journal of the Acoustical Society of America 146, no. 3 (September 2019): EL306—EL309. http://dx.doi.org/10.1121/1.5126924.

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Wittstock, Gunther. "Sensor arrays and array sensors." Analytical and Bioanalytical Chemistry 372, no. 1 (December 8, 2001): 16–17. http://dx.doi.org/10.1007/s00216-001-1149-y.

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Streibl, Nörbert, Uwe Nölscher, Jürgen Jahns, and Susan Walker. "Array generation with lenslet arrays." Applied Optics 30, no. 19 (July 1, 1991): 2739. http://dx.doi.org/10.1364/ao.30.002739.

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Liu, Qiaoge, Buhong Wang, Xia Li, Jiwei Tian, Tianhao Cheng, and Shuaiqi Liu. "An optimizing nested MIMO array with hole-free difference coarray." MATEC Web of Conferences 232 (2018): 01055. http://dx.doi.org/10.1051/matecconf/201823201055.

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According to the newly proposed nested MIMO (Multiple-Input Multiple-Input Multiple Output Multiple Array) array design method, we propose to replace the traditional nested array into an optimizing nested array, ie, to optimizing nested MIMO array design. It not only retains the original advantage of nested MIMO array design closed expression with array element position and degree of freedom(DOF), but also greatly improves the array aperture and DOF. Optimizing nested MIMO array firstly uses the optimizing nested array as the transmitting and receiving arrays, and then make the difference set processing for the coarray of MIMO array (coarray, CA). By properly designing the array spacing of the transmitting and receiving arrays, we can obtain a non-porous difference array. When the total number of array elements is given, by analyzing the characteristics of the array structure, the best array element number of the transmitting and receiving arrays can be obtained. Simulation experiments show that compared with the nested MIMO array design, the proposed method can effectively expand the array aperture, increase the DOF, and increase the DOA estimation accuracy of the MIMO radar without increasing the number of actual array elements.

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Thanh Binh, Nguyen, Nguyen Quoc Dinh, and Yoshihide Yamada. "Wideband characteristics of density tapered array antennas." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 2 (April 1, 2021): 1356. http://dx.doi.org/10.11591/ijece.v11i2.pp1356-1366.

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In this paper, wideband characteristics of density tapered arrays are clarified by comparing directly the array factors and radiation patterns of 3 tapered arrays structures with array factors and radiation patterns of equally spaced arrays. Calculated results for a density tapered distribution array consisting of 30 elements claims that the array can perform within a bandwidth of 2.5:1 with grating lobe levels lower than -7.8 dB. Additionally, this paper shows a method of determining the effectiveness of unequal spacing arrays in the design of actual antennas. The method is based on calculation and analysis of input impedance of array elements caused by mutual coupling effects among array elements.

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Sun, Muye, and Tianyu Duanmu. "DOA estimation technology based on array signal processing nested array." Applied and Computational Engineering 64, no. 1 (May 15, 2024): 23–29. http://dx.doi.org/10.54254/2755-2721/64/20241345.

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Research on non-uniform arrays has always been a focus of attention for scholars both domestically and internationally. Part of the research concentrates on existing non-uniform arrays, while another part focuses on optimizing the position of array elements or expanding the structure. Of course, there are also studies on one-dimensional and two-dimensional DOA estimation algorithms based on array spatial shapes, despite some issues. As long as there is a demand for spatial domain target positioning, the development and refinement of non-uniform arrays will continue to be a hot research direction. Nested arrays represent a unique type of heterogeneous array, whose special geometric shape significantly increases degrees of freedom and enhances estimation performance for directional information of undetermined signal sources. Compared to other algorithms, the one-dimensional DOA estimation algorithm based on spatial smoothing simplifies algorithm complexity, improves estimation accuracy under nested arrays, and can effectively handle the estimation of signal sources under uncertain conditions. The DFT algorithm it employs not only significantly improves angular estimation performance but also reduces operational complexity, utilizing full degrees of freedom to minimize aperture loss. Furthermore, the DFT-MUSIC method greatly reduces algorithmic computational complexity while performing very closely to the spatial smoothing MUSIC algorithm. The sparse arrays it utilizes, including minimum redundancy arrays, coprime arrays, and nested arrays, are a new type of array. Sparse arrays can increase degrees of freedom compared to traditional uniform linear arrays and solve the estimation of signal source angles under uncertain conditions, while also enhancing algorithm angular estimation performance.

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LECHTCHINSKY, ROMAN, MANUEL M. T. CHAKRAVARTY, and GABRIELE KELLER. "COSTING NESTED ARRAY CODES." Parallel Processing Letters 12, no. 02 (June 2002): 249–66. http://dx.doi.org/10.1142/s0129626402000951.

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We discuss a language-based cost model for array programs built on the notions of work complexity and parallel depth. The programs operate over data structures comprising nested arrays and recursive product-sum types. In a purely functional setting, such programs can be implemented by way of the flattening transformation that converts codes over nested arrays into vectorised code over flat arrays. Flat arrays lend themselves to a particularly efficient implementation on standard hardware, but the overall efficiency of the approach depends on the flattening transformation preserving the asymptotic complexity of the nested array codes. Blelloch has characterised a class of first-order array programs, called contained programs, for which flattening preserves the asymptotic depth complexity. However, his result is restricted to programs processing only arrays and tuples. In the present paper, we extend Blelloch's result to array programs processing data structures containing arrays as well as arbitrary recursive product-sum types. Moreover, we replace the notion of containment by the more general concept of fold programs.

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Fang, Li Qing, Hong Kai Wang, and Kai Chen. "Analysis of Directional Accuracy of Three Single Arrays." Advanced Materials Research 490-495 (March 2012): 1714–17. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.1714.

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Acoustic sensoxr array technology is the one of the key technology of passive acoustic detection technology, whether the single array has a good performance on direction will directly affect the accuracy of the locating system. In order to choose the best single array on direction, in this paper, respectively selected representative plane array and spatial array from a number of typical single arrays to analyze, find out the advantages and disadvantages of two single arrays. On this basis, around the idea of integrating the advantage of symmetric spatial array and plane cross five-element array, according to characteristics of the structure of this two kinds of arrays to design a new locating model—spatial five-element array. And compared with two kinds of single array mentioned above, the results of comparison show that the locating accuracy of spatial five-elements array is superior to both kinds of mentioned, and have high engineering value.

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Távora-Vieira, Dayse, Marcus Voola, Jafri Kuthubutheen, Peter Friedland, Daren Gibson, and Aanand Acharya. "Evaluation of the Performance of OTOPLAN-Based Cochlear Implant Electrode Array Selection: A Retrospective Study." Journal of Personalized Medicine 13, no. 8 (August 20, 2023): 1276. http://dx.doi.org/10.3390/jpm13081276.

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Otoplan is a surgical planning software designed to assist with cochlear implant surgery. One of its outputs is a recommendation of electrode array type based on imaging parameters. In this retrospective study, we evaluated the differences in auditory outcomes between patients who were implanted with arrays corresponding to those recommended by the Otoplan software versus those in which the array selection differed from the Otoplan recommendation. Pre-operative CT images from 114 patients were imported into the software, and array recommendations were generated. These were compared to the arrays which had actually been implanted during surgery, both in terms of array type and length. As recommended, 47% of patients received the same array, 34% received a shorter array, and 18% received a longer array. For reasons relating to structure and hearing preservation, 83% received the more flexible arrays. Those who received stiffer arrays had cochlear malformations or ossification. A negative, although non-statistically significant correlation was observed between the CNC scores at 12 months and the absolute value of the difference between recommended array and implanted array. In conclusion, clinicians may be slightly biased toward shorter electrode arrays due to their perceived greater ability to achieve full insertion. Using 3D imaging during the pre-operative planning may improve clinicians’ confidence to implant longer electrode arrays, where appropriate, to achieve optimum hearing outcomes.

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Acciaro, Vincenzo, and Amiya Nayak. "Characterization of Catastrophic Faults in Reconfigurable Systolic Arrays." VLSI Design 7, no. 2 (January 1, 1998): 143–50. http://dx.doi.org/10.1155/1998/79841.

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A common technique widely used to achieve fault tolerance in systolic arrays consists in incorporating in the array additional processing elements (PEs) and extra bypass links. Given a sufficient number of PEs and a large enough set of bypass links, it might seem that the array can easily tolerate a large number of faults provided they do not occur in consecutive locations. It is not always the case as shown in this paper. In fact, certain fault patterns exist and may occur which would prevent any kind of restructuring of the aray, thus making the structure unusable. For a given set of bypass links from each PE in the array, it is possible to identify such fault patterns which will prevent any reconfiguration. In this paper, we identify the class of fault patterns that are catastrophic for linear systolic arrays, examine their characteristics, and describe a method for constructing such fault patterns.

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Patwari, Ashish, and G. Ramachandra Reddy. "A Conceptual Framework for the Use of Minimum Redundancy Linear Arrays and Flexible Arrays in Future Smartphones." International Journal of Antennas and Propagation 2018 (September 18, 2018): 1–12. http://dx.doi.org/10.1155/2018/9629837.

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This work applies existing array processing principles to devise a new area of application. The properties of minimum redundancy linear arrays (MRLAs) and flexible arrays are studied, keeping in mind the possibility of using them in flexible 5G smartphones of the future. Millimeter frequencies for 5G communications enabled the use of a decent number of array elements, even at the user equipment (UE). MRLAs possess attractive properties among linear sparse arrays and flexible conformal arrays (flexible arrays) operate satisfactorily even when the surface they are built into changes shape. To the best of our knowledge, MRLAs were not applied to smartphones previously. In this work, a 16-element uniform linear array (ULA) and a 7-element MRLA (with the same aperture) are considered for simulations. Array factors of both the arrays in flat and bent positions have been computed using MATLAB. The effect of phase compensation and bending radii on the array pattern were verified. That phase compensation using the projection method (PM) restores the array pattern even for a bent MRLA is a major finding. Possible array processing modes have been suggested for a 5G smartphone in which the array could be made to operate in any of the four configurations: a flat ULA, a bent ULA, a flat MRLA, and a bent MRLA.

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Wu, Jinping, Wenxiao Qiao, Xiaohua Che, Xiaodong Ju, Junqiang Lu, and Wenhe Wu. "Experimental study on the radiation characteristics of downhole acoustic phased combined arc array transmitter." GEOPHYSICS 78, no. 1 (January 1, 2013): D1—D9. http://dx.doi.org/10.1190/geo2012-0114.1.

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A new kind of acoustic phased combined arc array transmitter with controllable directivity presented can be used in 3D acoustic image logging. The phased combined arc array is composed of numerous phased arc arrays placed equally along an axis. Each phased arc array contains several array elements arranged around a circumference. The phased combined arc array is considered as the combination of phased arc arrays and linear phased arrays. A directional radiation acoustic beam in the space is generated by simultaneously controlling the phase delay of excitation signals exerted on array elements located in the circumferential and axial directions. To investigate the radiation characteristics, an acoustic transmitter comprising four eight-element phased arc arrays was assembled to conduct physical simulation experiments in a water tank. Experimental results show that the main lobe width of the horizontal radiation energy narrows significantly by exerting phase delayed excitation signals on array elements of phased arc arrays. Adjusting the delay time of excitation signals applied on neighboring-phased arc arrays allows the main lobe direction of the vertical radiation energy to be steered and facilitates the change in the main lobe width of the vertical radiation energy. The phased combined arc array is characterized by controllable horizontal directivity, vertical directivity, and main lobe width of the radiated acoustic beam. More importantly, the acoustic phased combined arc array transmitter is applicable to 3D acoustic image logging, which is helpful in the enhancement of the reliability and accuracy of complex reservoir exploration.

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Al‐Kurd, Azmi A., and Robert P. Porter. "Holographic array processing using truncated arrays." Journal of the Acoustical Society of America 93, no. 4 (April 1993): 2373. http://dx.doi.org/10.1121/1.406125.

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Hoctor, R. T., and S. A. Kassam. "Array redundancy for active line arrays." IEEE Transactions on Image Processing 5, no. 7 (July 1996): 1179–83. http://dx.doi.org/10.1109/83.502396.

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Yu, Guicai. "Algorithm to Estimate Direction of Arrival with Interpolated Array Elements for Coprime Array Holes." Mathematical Problems in Engineering 2020 (August 31, 2020): 1–7. http://dx.doi.org/10.1155/2020/1429628.

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A novel method for adding antennas in the coprime arrays is introduced in this study, in order to solve the problem of the reduced degree of freedom of the array in the hole-existing coprime arrays. The minimum number of antennas interpolated in the algorithm maximizes the available degrees of freedom of virtual arrays, and the number of interpolated antennas does not change the original aperture size of the coprime arrays. With the proposed algorithm, the estimate of the direction of arrival is more accurate for a given signal-to-noise ratio. The scheme first finds the regular pattern of hole positions in virtual array elements, and then, according to the regular pattern, the position of the hole of the partial virtual array element is interpolated with the array element antenna at the position of the corresponding coprime arrays. The holes of the virtual array element are filled, giving virtual uniform continuous array elements with maximum degrees of freedom. We use the ESPRIT, and the simulation results show that the proposed algorithm improves the accuracy and resolution of estimates of the direction of arrival.

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PEYTON JONES, SIMON. "16 Arrays." Journal of Functional Programming 13, no. 1 (January 2003): 173–78. http://dx.doi.org/10.1017/s0956796803001813.

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HOU, Shuhua, Xuanzhi ZHAO, Zengli LIU, Yi PENG, and Na WANG. "Ternary redundant sparse linear array design with high robustness." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 41, no. 1 (February 2023): 125–35. http://dx.doi.org/10.1051/jnwpu/20234110125.

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Sparse linear array is prone to element failure affected by environmental and other factors in practical application, resulting in the decline of degrees of freedom and the attenuation or even failure of direction of arrival (DOA) estimation performance. To address this problem, a ternary redundant sparse array composed of three uniform linear arrays with different spacings at specific distances is designed, and the analytical expression of its degrees of freedom is derived. The configuration rules of the array are concise, and the difference coarrays of the array are hole-free. Mathematically proves that all virtual array elements can be covered with a weight of not less than 3 except the 4 farthest. The array has lower sensors importance and less generalized k-fragility. The array design takes into account the maximum degrees of freedom, redundancy and sparsity. In case of sensors failure, compared with the other sparse linear arrays, the array has more stable difference coarrays and higher uniform degrees of freedom. Compared with multiple-fold redundancy arrays, the array has lower mutual coupling. Simulation results show that the ternary redundant array has superior robustness and higher DOA estimation accuracy under sensors failure.

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Zhao, Jian, Qian Sun, Ning Zhou, Hao Liu, and Haizheng Wang. "A Photovoltaic Array Fault Diagnosis Method Considering the Photovoltaic Output Deviation Characteristics." International Journal of Photoenergy 2020 (March 1, 2020): 1–11. http://dx.doi.org/10.1155/2020/2176971.

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There are a large number of photovoltaic (PV) arrays in large-scale PV power plants or regional distributed PV power plants, and the output of different arrays fluctuates with the external conditions. The deviation and evolution information of the array output are easily covered by the random fluctuations of the PV output, which makes the fault diagnosis of PV arrays difficult. In this paper, a fault diagnosis method based on the deviation characteristics of the PV array output is proposed. Based on the current of the PV array on the DC (direct current) side, the deviation characteristics of the PV array output under different arrays and time series are analyzed. Then, the deviation function is constructed to evaluate the output deviation of the PV array. Finally, the fault diagnosis of a PV array is realized by using the probabilistic neural network (PNN), and the effectiveness of the proposed method is verified. The main contributions of this paper are to propose the deviation function that can extract the fault characteristics of PV array and the fault diagnosis method just using the array current which can be easily applied in the PV plant.

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Micek, Piotr, and Dariusz Grzybek. "Experimental Analysis of the Arrays of Macro Fiber Composite Patches for Rotational Piezoelectric Energy Harvesting from a Shaft." Energies 14, no. 16 (August 7, 2021): 4815. http://dx.doi.org/10.3390/en14164815.

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Four arrays of three MFC patches, glued onto a rotating shaft, were compared in laboratory research. The first array was based on a delta circuit and equipped with one three-phase rectifier; the second array was based on a star circuit and equipped with one three-phase rectifier; the third array was based on parallel connection and equipped with three full-bridge rectifiers; and the fourth array was based on a series connection and equipped with three full-bridge rectifiers. The array based on a delta circuit generated the highest value of maximal electric power in comparison to the rest of arrays. It was experimentally observed that the arrays based on delta or star circuits of MFC patches and equipped with one three-phase rectifier generated a higher value of maximal power than arrays based on the connections of three full-bridge rectifiers, connected in parallel or in series. The array based on parallel connection generated the highest maximal value of current in comparison to rest of arrays for low values of load resistance (from 10 kΩ to 40 kΩ depending on the experiment). For higher values of load resistance arrays based on delta circuits and star circuits generated higher values of current than the array based on parallel connection.

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Venkata Rama Rao, S., A. Mallikarjuna Prasad, and Ch Santhi Rani. "Direction of Arrival Estimation of Uncorrelated Signals Using Root-MUSIC Algorithm for ULAs and UCAs." International Journal of Engineering & Technology 7, no. 4.36 (December 9, 2018): 398. http://dx.doi.org/10.14419/ijet.v7i4.36.23813.

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In this paper, Root-MUSIC algorithm for direction of arrival (DOA) estimation of uncorrelated signals is explored both for uniform linear and uniform circular arrays. The basic problem in Uniform Linear Arrays (ULAs) is Mutual coupling between the individual elements of the antenna array. This problem is reduced in Uniform Circular Arrays (UCAs) because of its symmetric structure. The DOA estimation of uncorrelated signals that have different power levels is simulated on a MATLAB environment. And the noise consider is white across all the array elements. The factors considered for simulation are number of number of snapshots, array elements, radius of circular array, array length, and signal to noise ratio.

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Yoon, Hansol, and Tai-Kyong Song. "Sparse Rectangular and Spiral Array Designs for 3D Medical Ultrasound Imaging." Sensors 20, no. 1 (December 27, 2019): 173. http://dx.doi.org/10.3390/s20010173.

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In three-dimensional (3D) medical ultrasound imaging with two-dimensional (2D) arrays, sparse 2D arrays have been studied to reduce the number of active channels. Among them, sparse 2D arrays with regular or uniform arrangements of elements have advantages of low side lobe energy and uniform field responses over the entire field of view. This paper presents two uniform sparse array models: sparse rectangular arrays (SRAs) on a rectangular grid and sparse spiral arrays (SSAs) on a sunflower grid. Both arrays can be easily implemented on the commercially available or the custom-made arrays. To suppress the overall grating lobe levels, the transmit (Tx) and receive (Rx) array pairs of both the array models are designed not to have grating lobes at the same locations in the Tx/Rx beam patterns, for which the theoretical design rules are also proposed. Computer simulation results indicate that the proposed array pairs for both the SRAs and the SSAs achieve peak grating lobe levels below –40 dB using about a quarter of the number of elements in the dense rectangular array while maintaining similar beam widths to that of the dense array pair.

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Wang, Wei, Min Zhu, and Bo Yang. "Positioning Combination Method of USBL Using Four-Element Stereo Array." Sensors 21, no. 22 (November 20, 2021): 7722. http://dx.doi.org/10.3390/s21227722.

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In the present article, an ultra-short baseline (USBL) combined location method based on three four-element stereo arrays is proposed. In order to solve the problem of the poor positioning effect of acoustic positioning under a high incident angle of signal, two kinds of four-element stereo arrays are designed, and the localization approach of the new array is given. At the same time, for the regular triangular pyramid array, a virtual array element is proposed to construct a planar cross array to improve the poor positioning effect of the regular triangular pyramid array at a low incident angle. This paper analyzes the positioning performance of three arrays. Combined with the traditional cross-planar array localization method, a set of positioning strategies to switch the two localization methods under different incident angles were designed. The switching thresholds of the two methods were analyzed by simulation. Simulation results show that the new arrays can locate stably at different incident angles and improve the overall positioning performance of the array.

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Fang, Li Qing, Hong Kai Wang, and Kai Chen. "Design of Passive Acoustic Location System Based on Double Arrays." Advanced Materials Research 490-495 (March 2012): 1857–61. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.1857.

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The biggest advantage passive acoustic positioning system based on single array is that it has high performance on orientation. However, its positioning error is usually larger. Locating based on multi-array not only gives more information to enhance the locating accurate, but also can eliminate the blind area generated by single array. So its locating performance is better than single-base array. In this paper, taking the system of double arrays for instance, built a passive acoustic positioning system, gave the plan of the system, and designed the tests to compare the accuracy between the single array and double arrays. According to the tests, it further verified that locating system based on double arrays has higher accuracy than the system of single array. And it also has high value engineering.

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Liu, Yuanyuan, Dongyue Jin, Xin Lei, Yuxin Zhou, Wanrong Zhang, Hongytm Xie, Weicong Na, Jlngfing Dai, and Zhiyong Wang. "Improvement of current crowding effect in VCSEL arrays with non-uniform oxidation aperture design." MATEC Web of Conferences 395 (2024): 01002. http://dx.doi.org/10.1051/matecconf/202439501002.

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A compact electro-opto-thermal model of 2-D vertical cavity surface emitting laser (VCSEL) arrays considering the current crowding effect in each array cell is established to study the impact of oxidation aperture on the device performance. Simulated results shows that increasing oxidation aperture of array cell is helpful to improve the uniformity of current density distribution. With careful design of non-uniform oxidation aperture layout, both the uniformity of the temperature distribution and the current distribution is improved by 36.52% and 42.08%, respectively. Furthermore, 3×3 VCSEL arrays with uniform oxidation aperture (array-1) and non-uniform oxidation aperture (array-2) are fabricated and the L-I-V curves of two types of VCSEL arrays at different biases are also measured. The peak output optical power of array-2 is enhanced to 1.83mW with an improvement of 8.91% when compared with that of array-1. Moreover, the total optical output power of array-2 is always superior to that of array-1 over a wide bias current range.

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Sun, Lei, Minglei Yang, and Baixiao Chen. "Thermos Array: Two-Dimensional Sparse Array with Reduced Mutual Coupling." International Journal of Antennas and Propagation 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/3624514.

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Sparse planar arrays, such as the billboard array, the open box array, and the two-dimensional nested array, have drawn lots of interest owing to their ability of two-dimensional angle estimation. Unfortunately, these arrays often suffer from mutual-coupling problems due to the large number of sensor pairs with small spacing d (usually equal to a half wavelength), which will degrade the performance of direction of arrival (DOA) estimation. Recently, the two-dimensional half-open box array and the hourglass array are proposed to reduce the mutual coupling. But both of them still have many sensor pairs with small spacing d, which implies that the reduction of mutual coupling is still limited. In this paper, we propose a new sparse planar array which has fewer number of sensor pairs with small spacing d. It is named as the thermos array because its shape seems like a thermos. Although the resulting difference coarray (DCA) of the thermos array is not hole-free, a large filled rectangular part in the DCA can be facilitated to perform spatial-smoothing-based DOA estimation. Moreover, it enjoys closed-form expressions for the sensor locations and the number of available degrees of freedom. Simulations show that the thermos array can achieve better DOA estimation performance than the hourglass array in the presence of mutual coupling, which indicates that our thermos array is more robust to the mutual-coupling array.

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Han, Rong Rong, and Hui Sun. "Calculation of Array Gain in the Reverberation Field." Advanced Materials Research 457-458 (January 2012): 644–49. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.644.

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If the number and the location of each cell in the array is determined, the space array processing gain is constant in designing the uniform line array in isotropic acoustic field. However, the spatial distribution of reverberation field will affect against the array gain, when the arrays are in anisotropic reverberation field. Reverberation is the unique interference of active sonar, and the energy distribution of space in reverberation field is anisotropic and random. Therefore, the arrays gain problem can be get in researching on the correlation between arrays in the reverberant field. In this paper, the calculation method is simple and useful which is calculated line array gain using the correlation coefficient in the reverberant field.

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Yu, Jing Jing, and Fa Shan Yu. "Evolutionary Algorithm for Microphone Array Optimization." Applied Mechanics and Materials 143-144 (December 2011): 287–92. http://dx.doi.org/10.4028/www.scientific.net/amm.143-144.287.

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This paper presented a genetic algorithm (GA) to optimize element placements of microphone array with the purpose of maximizing beamforming SNR for given possible distribution of sound sources. A function based on relationship between statistical geometry descriptors and array performance matrices was applied as the objective function of GA. Optimization experiments of 1D linear array and 2D planar array were performed to demonstrate that this algorithm can effectively sort out superior arrays with significant SNR improvements over randomly generated arrays and regular arrays. High successful rate, rapid convergence speed, and fast processing time observed in all the experiments demonstrate the feasibility of this algorithm as a practical tool for microphone array design.

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O'NEILL, MELISSA E., and F. WARREN BURTON. "A new method for functional arrays." Journal of Functional Programming 7, no. 5 (September 1997): 487–513. http://dx.doi.org/10.1017/s0956796897002852.

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Arrays are probably the most widely used data structure in imperative programming languages, yet functional languages typically only support arrays in a limited manner, or prohibit them entirely. This is not too surprising, since most other mutable data structures, such as trees, have elegant immutable analogues in the functional world, whereas arrays do not. Previous attempts at addressing the problem have suffered from one of three weaknesses, either that they don't support arrays as a persistent data structure (unlike the functional analogues of other imperative data structures), or that the range of operations is too restrictive to support some common array algorithms efficiently, or that they have performance problems. Our technique provides arrays as a true functional analogue of imperative arrays with the properties that functional programmers have come to expect from their data structures. To efficiently support array algorithms from the imperative world, we provide O(1) operations for single-threaded array use. Fully persistent array use can also be provided at O(1) amortized cost, provided that the algorithm satisfies a simple requirement as to uniformity of access. For those algorithms which do not access the array uniformly or single-threadedly, array reads or updates take at most O(log n) amortized time, where n is the size of the array. Experimental results indicate that the overheads of our technique are acceptable in practice for many applications.

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Sankar, V. A., and P. V. Y. Jayasree. "Design and Analysis of Novel Fractal Linear and Planar Array Antennas for Satellite Applications." Advanced Electromagnetics 5, no. 3 (December 1, 2016): 56. http://dx.doi.org/10.7716/aem.v5i3.400.

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This article proposed a new geometric design methodology for the systematic expansion of fractal linear and planar array antennas. Using this proposed geometric design methodology any deterministic polygon shape can be constructed. In this article, two element fractal linear and triangular array antennas are examined using proposed methodology up to four iterations of two expansion factors. Due to the repetitive nature of the proposed geometric design methodology, both linear and planar fractal arrays shows multi-beam behavior with excellent array factor properties. The behavior of the proposed arrays shows better performance than linear and planar fractal array antennas generated by concentric circular ring sub array geometric generator. Triangular planar fractal array of expansion factor two at fourth iteration achieved a single valued beam width of 3.80 with -31.6 side lobe level. The suggested fractal arrays are analyzed and simulated by MATLAB-13 programming.

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Liu, Jiancheng, Feng Shi, Yecheng Sun, and Peng Li. "An ADS-Based Sparse Optimization Method for Sonar Imaging Sensor Arrays." Applied Sciences 10, no. 9 (May 2, 2020): 3176. http://dx.doi.org/10.3390/app10093176.

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The Mills Cross sonar sensor array, achieved by the virtual element technology, is one way to build a low-complexity and low-cost imaging system while not decreasing the imaging quality. This type of sensor array is widely investigated and applied in sensor imaging. However, the Mills Cross array still holds some redundancy in sensor spatial sampling, and it means that this sensor array may be further thinned. For this reason, the Almost Different Sets (ADS) method is proposed to further thin the Mills Cross array. First, the original Mills Cross array is divided into several transversal linear arrays and one longitudinal linear array. Secondly, the Peak Side Lobe Level (PSLL) of each virtual linear array is estimated in advance. After the ADS parameters are matched according to the thinned ratio of the expectant array, all linear arrays are thinned in order. In the end, the element locations in the thinned linear array are used to determine which elements are kept or discarded from the original Mills array. Simulations demonstrate that the ADS method can be used to thin the Mills array and to further decrease the complexity of the imaging system while retaining beam performance.

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Zhang, Hang, Chunchi Ma, and Tianbin Li. "Quantitative Evaluation of the “Non-Enclosed” Microseismic Array: A Case Study in a Deeply Buried Twin-Tube Tunnel." Energies 12, no. 10 (May 25, 2019): 2006. http://dx.doi.org/10.3390/en12102006.

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The high-stress hazards of underground engineering have stimulated the exploration of microseismic monitoring and early warning methods. To achieve a good monitoring effect, the monitoring object is usually enclosed by a microseismic array (sensor array) (e.g., slope engineering, etc.). However, some characteristics of a buried tunnel, including “linear”, “deep-buried”, and “long”, make it difficult to deploy a reasonable microseismic array, which leads to the microseismic array being non-enclosed for the monitoring object. Application of the non-enclosed microseismic array yields decreases the accuracy of the source location. To solve the problem wisely, this paper deals with the feasibility of non-enclosed microseismic arrays (axial-extended, lateral-extended, and twin-tube arrays) by introducing a quantitative method. To this end, an optimized microseismic array with the best source location accuracy for a twin-tube expressway tunnel is proposed. The obtained results reveal that the non-enclosed microseismic arrays, which are unavoidable in expressway tunnel engineering, do not introduce errors but reduce the ability to resist them. Further, the twin-tube array achieves a better source location accuracy than the axial and lateral-extended arrays. In the application of the source location based on the particle swarm optimization (PSO) algorithm to the twin-tube array, microseismic events, which cluster in the rockburst section, are wholly gathered, and the maximum error is reduced by about 30–50 m, indicating its greater feasibility with respect to the single-tube array.

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Okamoto, Kyoka, and Kan Okubo. "Arrangement design for horizontally omnidirectional audible sound source using facing ultrasonic transducer arrays." Japanese Journal of Applied Physics 61, SG (March 30, 2022): SG1028. http://dx.doi.org/10.35848/1347-4065/ac4c09.

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Abstract We developed an audible sound source with horizontal omnidirectional patterns using facing ultrasonic transducer arrays. The arrays emitted sound with different ultrasonic frequencies from each side, and an audible sound with a differential frequency is generated between input ultrasonic signals. In particular, we designed and created a new array that can control the number of transducers driven in the array. We evaluated the frequency–amplitude characteristics and directivity when the transducers in the array were driven in an annular shape. There is an optimum array shape and number of transducers that can be driven for a specific distance between arrays.

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Woo, Myung Kyun, Lance DelaBarre, Matt Thomas Waks, Young Woo Park, Russell Luke Lagore, Steve Jungst, Yigitcan Eryaman, Se-Hong Oh, Kamil Ugurbil, and Gregor Adriany. "Evaluation of 8-Channel Radiative Antenna Arrays for Human Head Imaging at 10.5 Tesla." Sensors 21, no. 18 (September 8, 2021): 6000. http://dx.doi.org/10.3390/s21186000.

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For human head magnetic resonance imaging at 10.5 tesla (T), we built an 8-channel transceiver dipole antenna array and evaluated the influence of coaxial feed cables. The influence of coaxial feed cables was evaluated in simulation and compared against a physically constructed array in terms of transmit magnetic field (B1+) and specific absorption rate (SAR) efficiency. A substantial drop (23.1% in simulation and 20.7% in experiment) in B1+ efficiency was observed with a tight coaxial feed cable setup. For the investigation of the feed location, the center-fed dipole antenna array was compared to two 8-channel end-fed arrays: monopole and sleeve antenna arrays. The simulation results with a phantom indicate that these arrays achieved ~24% higher SAR efficiency compared to the dipole antenna array. For a human head model, we observed 30.8% lower SAR efficiency with the 8-channel monopole antenna array compared to the phantom. Importantly, our simulation with the human model indicates that the sleeve antenna arrays can achieve 23.8% and 21% higher SAR efficiency compared to the dipole and monopole antenna arrays, respectively. Finally, we obtained high-resolution human cadaver images at 10.5 T with the 8-channel sleeve antenna array.

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Wu, Tao, Yiwen Li, Zhengxin Li, Yijie Huang, and Jiwei Xu. "A 2D Nested Array Based DOA Estimator for Incoherently Distributed Sources via Sparse Representation Utilizing L1-Norm." International Journal of Antennas and Propagation 2019 (July 3, 2019): 1–11. http://dx.doi.org/10.1155/2019/6941963.

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Nested arrays are sparse arrays composed of subarrays with nonuniform sensor spacing. Compared with traditional uniform arrays, nested arrays have more degree of freedoms (DOFs) and larger apertures. In this paper, a nested array has been proposed as well as a direction-of-arrival (DOA) estimation method for two-dimensional (2D) incoherently distributed (ID) sources. A virtual array is firstly obtained through vectorization of the cross-correlation matrix of subarrays. Sensor positions of the virtual array and the optimal configuration of the nested array are derived next. Then rotational invariance relationship for generalized steering matrix of the virtual array with respect to nominal azimuth is deduced. According to the rotational invariance relationship, sparse representation model under l1-norm constraint is established, which is resolved by transferring the objective function to second-order cone constraints and combining a estimation residual error constraint for receive vector of the virtual array. Simulations are conducted to investigate the effectiveness of the proposed method in underdetermined situation and examine different experiment factors including SNR, snapshots, and angular spreads as well as sensor number of subarrays. Results show that the proposed method has better performance than uniform parallel arrays with the same number of sensors.

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Mudiyala, Jahnavi, Hayeong Shim, Donghyun Kim, and Yongrae Roh. "Development of a Dual-Layer Structure for Cymbal Transducer Arrays to Achieve a Wider Bandwidth." Sensors 22, no. 17 (September 1, 2022): 6614. http://dx.doi.org/10.3390/s22176614.

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Cymbal transducers are typically grouped and arranged in planar arrays. For projector arrays, a wide bandwidth on the transmitting voltage response (TVR) spectrum is required for better underwater communication and data transmission within a short time. The purpose of this study is to develop a wideband cymbal array by controlling the center-to-center (CTC) spacing between the cymbal transducers in the array. In the practical design of the array, due to the arrangement of elements in one layer, the minimum CTC spacing between the cymbals is constrained to the diameter of the cymbals in use. To overcome this limitation, we propose a new dual-layer array structure. Finite element analysis of the cymbal array showed that the bandwidth was generally inversely proportional to the CTC spacing. We explained the mechanism of this relationship using a theoretical analysis of the mutual radiation impedance between the cymbals in the array. Subsequently, we identified the optimum CTC spacing to achieve the widest possible bandwidth for the cymbal array. The validity of the wideband array design was verified through the fabrication and characterization of prototype arrays. We confirmed that the two-layered arrangement could significantly widen the bandwidth of the cymbal array while maintaining the TVR above a specified level.

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Chepala, Anil, Vincent Fusco, Umair Naeem, and Adrian McKernan. "Uniform Linear Antenna Array Beamsteering Based on Phase-Locked Loops." Electronics 12, no. 4 (February 4, 2023): 780. http://dx.doi.org/10.3390/electronics12040780.

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Phased arrays are extensively used in many modern beam-scanning applications such as radar and satellite communications. Electronic beam scanning makes phased arrays an important aspect of modern antenna array systems. This Tutorial aims to promote the basic understanding of the principle and operation of a phased array to general undergraduate students. This paper starts with a discussion on the theory of operation and some basic definitions of antenna parameters followed by derivations of two-element and N-element array patterns and, finally, a five-element array design. The essential hardware based on Phase-Locked Loops (PLLs) as phase controllable RF sources required to build an array and the basic tools required for software and measurement set-up to demonstrate the beam-scanning phased array operation are presented. This enables students to quickly understand and set-up an experiment to verify the phased array operation with commercial off-the-shelf components. In addition, the hardware and software necessary for autonomous control are discussed. By combining basic concepts of phase arrays with a series of simple coding and intuitive laboratory experiments, students can easily understand the Uniform Linear Array (ULA) scanning operation.

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Dorer, Douglas R., and Steven Henikoff. "Transgene Repeat Arrays Interact With Distant Heterochromatin and Cause Silencing in cis and trans." Genetics 147, no. 3 (November 1, 1997): 1181–90. http://dx.doi.org/10.1093/genetics/147.3.1181.

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Tandem repeats of Drosophila transgenes can cause heterochromatic variegation for transgene expression in a copy-number and orientation-dependent manner. Here, we demonstrate different ways in which these transgene repeat arrays interact with other sequences at a distance, displaying properties identical to those of a naturally occurring block of interstitial heterochromatin. Arrays consisting of tandemly repeated white transgenes are strongly affected by proximity to constitutive heterochromatin. Moving an array closer to heterochromatin enhanced variegation, and enhancement was reverted by recombination of the array onto a normal sequence chromosome. Rearrangements that lack the array enhanced variegation of white on a homologue bearing the array. Therefore, silencing of white genes within a repeat array depends on its distance from heterochromatin of the same chromosome or of its paired homologue. In addition, white transgene arrays cause variegation of a nearby gene in cis, a hallmark of classical position-effect variegation. Such spreading of heterochromatic silencing correlates with array size. Finally, white transgene arrays cause pairing-dependent silencing of a non-variegating white insertion at the homologous position.

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Galli-Resta, Lucia, Elena Novelli, and Alessandro Viegi. "Dynamic microtubule-dependent interactions position homotypic neurones in regular monolayered arrays during retinal development." Development 129, no. 16 (August 15, 2002): 3803–14. http://dx.doi.org/10.1242/dev.129.16.3803.

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In the vertebrate retina cell layers support serial processing, while monolayered arrays of homotypic neurones tile each layer to allow parallel processing. How neurones form layers and arrays is still largely unknown. We show that monolayered retinal arrays are dynamic structures based on dendritic interactions between the array cells. The analysis of three developing retinal arrays shows that these become regular as a net of dendritic processes links neighbouring array cells. Molecular or pharmacological perturbations of microtubules within dendrites lead to a stereotyped and reversible disruption of array organization: array cells lose their regular spacing and the arrangement in a monolayer. This leads to a micro-mechanical explanation of how monolayers of regularly spaced ‘like-cells’ are formed.

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Szalai, Sándor, László Szarka, Erno˝ Prácser, Frank Bosch, Imre Müller, and Pascal Turberg. "Geoelectric mapping of near‐surface karstic fractures by using null arrays." GEOPHYSICS 67, no. 6 (November 2002): 1769–78. http://dx.doi.org/10.1190/1.1527077.

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The term “null array” is introduced for those electrode configurations where the measured potential difference is zero above a homogeneous half‐space when using a measuring dipole M0N0. Different types of null arrays (three‐electrode, Schlumberger, and dipole axial/equatorial null arrays) and their corresponding traditional arrays are studied. It was shown in a field study carried out in a karstified limestone area covered by thin sediments that it is possible to obtain geologically meaningful results with null‐array techniques. The main features of the null‐array data are as follows. (1) Null‐array data appear to be more spatially variable than the classical data. The spatial variability provides information about the presence of karstic fractures in the subsurface; (2) The null‐array anomalies caused by nearly vertical karstic fractures in the limestone basement do not decay with depth as quickly as the classical array anomalies. (3) The strike direction of the fractures is much less ambiguous than that found by using classical arrays. Nevertheless, the depth variation of the basement is more reliably observed in geoelectric anomalies obtained using traditional arrays. Therefore a joint use of classical arrays and their corresponding null methods is recommended, because the combined methods provide more information about the subsurface structure.

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ma, fei, Sipei Zhao, and Thushara Abhayapala. "Physics-informed neural network assisted spherical microphone array signal processing." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A182. http://dx.doi.org/10.1121/10.0023200.

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Thanks to their rotational symmetry that facilitates three-dimensional signal processing, spherical microphone arrays are the common array apertures used for spatial audio and acoustic applications. However, practical implementations of spherical microphone arrays suffer from two issues. First, at high frequency range, a large number of sensors are needed to accurately capture a sound field. Second, the accompanying signal processing algorithm, i.e., the spherical harmonic decomposition method, requires a variable radius array or a rigid surface array to circumvent the spherical Bessel function nulls. Such arrays are hard to design and introduce a scattering field. To address these issues, this paper proposes to assist a spherical microphone array with a physics-informed neural network (PINN) for three-dimensional signal processing. The PINN models the sound field around the array based on the sensor measurements and the acoustic wave equation, augmenting the sound field information captured by the array through prediction. This makes it possible to analyze a high frequency sound field with a reduced number of sensors and avoid the spherical Bessel function nulls with a simple single radius open-sphere microphone array.

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Zalipynis, Ramon Antonio Rodriges. "Array DBMS." Proceedings of the VLDB Endowment 14, no. 12 (July 2021): 3186–89. http://dx.doi.org/10.14778/3476311.3476404.

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Array DBMSs strive to be the best systems for managing, processing, and even visualizing big N -d arrays. The last decade blossomed with R&D in array DBMS, making it a young and fast-evolving area. We present the first comprehensive tutorial on array DBMS R&D. We start from past impactful results that are still relevant today, then we cover contemporary array DBMSs, array-oriented systems, and state-of-the-art research in array management, flavored with numerous promising R&D opportunities for future work. A great deal of our tutorial was not covered in any previous tutorial or survey article. Advanced array management research is just emerging and many R&D opportunities still "lie on the surface". Hence, nowadays we have the most favorable conditions to start contributing to this research area. This tutorial will jump-start such efforts.

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Park, Jinsu, Hong Jun Lim, Son Trinh-Van, Daesung Park, Youn Kwon Jung, Dongju Lim, and Keum Cheol Hwang. "Derivation of a Universally Valid Array Factor of a Conformal Arrays Based on Phase Compensation and Genetic Learning Particle Swarm Optimization." Applied Sciences 12, no. 13 (June 27, 2022): 6501. http://dx.doi.org/10.3390/app12136501.

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In this study, we investigated the recent deterioration of the radiation pattern performance of conformal arrays, which are applied to fields such as aircraft and vehicles. We analyzed the radiation pattern of conformal arrays in the array factor stage by combining previous studies on various beam-forming techniques for conformal arrays. To efficiently calculate and utilize the radiation pattern of conformal arrays, we derived an array factor based on phase composition for nonplanar arrays of three-dimensional (3D) coordinate systems. As an amplitude tapering method for controlling the sidelobe level of the derived 3D array factor, we propose a Bernstein polynomial generalization method based on Genetic Learning Particle Swarm Optimization. The proposed 3D array factor was verified using a cavity-backed patch antenna operating at the X-band through EM simulation of conformal arrays as a single element.

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Sahalos, John N. "Lowering the Sidelobe Level of a Two-Way Pattern in Shared Aperture Radar Arrays." International Journal of Antennas and Propagation 2021 (January 6, 2021): 1–10. http://dx.doi.org/10.1155/2021/6685565.

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A study of lowering the peak SLL of shared aperture radar arrays is presented. A two-weight amplitude distribution for the elements of transmit and receive arrays is used. Imposing certain conditions, the relation of the number of elements of the arrays was found. One condition imposes the appearance of a minor lobe position of transmit or receive array pattern at a certain null of receive or transmit array pattern. A second condition imposes the equal sidelobe level of two consecutive minor lobes either near the main beam of the two-way array pattern or at certain positions of receive or transmit array pattern. The resulting peak SLL of the two-way radar array pattern depending on the conditions reaches from −47 dB up to less than −50 dB.

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Divett, T., R. Vennell, and C. Stevens. "Optimization of multiple turbine arrays in a channel with tidally reversing flow by numerical modelling with adaptive mesh." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1985 (February 28, 2013): 20120251. http://dx.doi.org/10.1098/rsta.2012.0251.

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At tidal energy sites, large arrays of hundreds of turbines will be required to generate economically significant amounts of energy. Owing to wake effects within the array, the placement of turbines within will be vital to capturing the maximum energy from the resource. This study presents preliminary results using Gerris, an adaptive mesh flow solver, to investigate the flow through four different arrays of 15 turbines each. The goal is to optimize the position of turbines within an array in an idealized channel. The turbines are represented as areas of increased bottom friction in an adaptive mesh model so that the flow and power capture in tidally reversing flow through large arrays can be studied. The effect of oscillating tides is studied, with interesting dynamics generated as the tidal current reverses direction, forcing turbulent flow through the array. The energy removed from the flow by each of the four arrays is compared over a tidal cycle. A staggered array is found to extract 54 per cent more energy than a non-staggered array. Furthermore, an array positioned to one side of the channel is found to remove a similar amount of energy compared with an array in the centre of the channel.

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Journal articles on the topic 'Array'

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