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In this paper, a patch antenna is proposed with reconfigurable patterns in the azimuth plane. The basic structure of the antenna is a circular patch upon which a vertical slot is etched. In addition, a row of shorting posts along the horizontal direction is placed underneath the patch. With the aid of characteristic mode analysis (CMA), reconfigurable patterns are achieved by synthesizing the currents of different modes. By switching over different sets of feeding ports, four steerable beams capable of covering the entire azimuth plane are obtained. One unique feature is that when the beam is switched to the direction orthogonal to it, the shape of the pattern will be switched accordingly. The antenna was fabricated and measured. The measured F/B ratio is close to 10 dB at 2.08 GHz, and the 3-dB beamwidth in the elevation (azimuth) plane is switchable from 82° (181°) to 190° (91°).

To solve some problems of high spatial resolution remote sensing images caused by land coverage, building coverage and shading of trees, such as difficult road extraction and low precision, a road extraction method based on multi-task key point constraints is put forward in this article based on Linknet. At the preprocessing stage, an auxiliary constraint task is designed to solve the connectivity problem caused by shading during road extraction from remote sensing images. At the encoding & decoding stage, first, a position attention (PA) mechanism module and channel attention (CA) mechanism module are applied to realize the effective fusion of semantic information in the context during road extraction. Second, a multi-branch cascade dilated spatial pyramid (CDSP) is established with dilated convolution, by which the problem of loss of partial information during information extraction from remote sensing road image is solved and the detection accuracy is further improved. The method put forward in this article is verified through the experiment with public datasets and private datasets, revealing that the proposed method provides better performance than several state of the art techniques in terms of detection accuracy, recall, precision, and F1-score.

A novel fixed-frequency beam switchable dual-beam antenna array is presented, which consists five dual-beam leaky-wave antenna (LWA) elements designed on substrate integrated waveguide (SIW) and integrated together on a common substrate. The LWAs work on fundamental wave and -1th spatial harmonic wave simultaneously and excite two symmetrical radiation beams in forward and backward direction respectively. In order to realize beam switching, three voltage-driven radio frequency chip switches (CSW-RFs) are used and integrated behind the antenna aperture. Since the periodic slot in LWA causes open stopband at the operating frequency, so the staggered radius amplification of local vias in the via walls of SIW is performed to suppress the open stopband. In addition, electromagnetic band-gap (EBG) structures, capable of reducing coupling between neighboring antenna elements, are embedded in between LWAs. The proposed dual-beam antenna array with beam switching capability between ±35, ±45, ±55, ±65 and ±75 degrees at 28 GHz are simulated, fabricated and measured. Both analysis and measurement results show that the proposed antenna array exhibits an excellent performance, which can be used in fixed-frequency beam-switching millimeter wave communication.

Convolutional neural networks (CNNs) have become continually deeper. With the increasing depth of CNNs, the invalid calculations caused by padding-zero operations, filling-zero operations and stride length (stride length 1) represent an increasing proportion of all calculations. To adapt to different CNNs and to eliminate the influences of padding-zero operations, filling-zero operations and stride length on the computational efficiency of the accelerator, we draw upon the computation pattern of CPUs to design an efficient and versatile CNN accelerator, LACS (Loading-Addressing-Computing-Storing). We reduce the amount of data movements between registers and the on-chip buffer from O(k × k) to O(k) by a bypass buffer mechanism. Finally, we deploy LACS on a field-programmable gate array (FPGA) chip and analyze the factors that affect the computational efficiency of LACS. We also run popular CNNs on LACS. The results show that LACS achieves an extremely high computational efficiency, 98.51% when executing AlexNet and 99.66% when executing VGG-16, significantly exceeding state-of-the-art accelerators.

In this paper, a smart antenna array based on the image-aware technique that can automatically switch its beam to track users is proposed. Mobilenet, a deep neural network (DNN), is utilized to find the users' position information from images; it is trained using the collected dataset, and the parameters are optimized. The modified DNN is then implanted into a miniaturized embedded system RK3399. To obtain beam switchable radiation, a 2×2 microstrip patch antenna array with a 4×4 Butler feeding matrix is designed in the 2.4 GHz ISM band. Then, the RK3399 is compactly integrated with the patch antenna array, and a microcamera is used as the eye of the antenna to capture the environment information. A series of measurements of the received power and error vector magnitude (EVM) are performed in a real indoor scenario to verify the design. The results agree well with the expected results and show that the design is capable of guaranteeing communication quality and improving energy efficiency, making this technique a good candidate for indoor wireless applications.

In order to reduce the misdiagnosis caused by outpatient triage error and help triage nurses to improve their triage accuracy, a general outpatient triage system based on the hybrid Dynamic Uncertain Causality Graph (hybrid DUCG) is presented. The hybrid DUCG is a combination of the single-valued DUCG (S-DUCG) and the multivalued DUCG (M-DUCG). In this paper, the M-DUCG is utilized to construct the basic outpatient triage knowledge base. In the knowledge base, each department is modeled as one sub-M-DUCG. It describes the causal relations between the department and its associated clinical features. All the sub-M-DUCGs are compiled into one M-DUCG as the basic outpatient triage knowledge base. The S-DUCG is employed to adjust the basic knowledge base to match the variant triage requirements for various hospitals. To validate the triage system, we constructed a basic triage knowledge base and adjusted it to match the triage requirement of a county-level hospital. Verification experiments were performed based on the adjusted triage knowledge base. The result showed that the triage system has high triage accuracy, and it can effectively assist triage nurses in outpatient triage.

A substrate integrated waveguide (SIW) leaky-wave antenna (LWA) array with beam-formed radiation pattern is investigated in this paper. The array is composed of two LWA elements with different parameters of slots. For each LWA, the period of slots is selected first within the scope of only n = -1 space harmonic radiation to ensure the beam radiate in the desired direction. Then, the length of the slots is tapered according to the binomial aperture distribution to get the wide beam. Finally, the width of the slots is adjusted to get the desired radiation field strength. By superposing two wide beams from two elements in a weighting way, a cosecant-squared-like beam-formed radiation pattern is realized, which is preferable for the application of uniform radio wave coverage in a long straight confined space. The array is fabricated and measured, and the measured results are consistent with the simulated results.

In this letter, a novel dual-beam and tri-band leaky-wave antenna (LWA) based on substrate integrated waveguide (SIW) structure is proposed, which has the capability of wide beam scanning range including broadside direction. The antenna consists of two kinds of periodic structures which can excite two -1st spatial harmonic waves and result in two radiation beams simultaneously. Through theoretical dispersion diagram analysis of the unit cells of two periodic structures and by applying the techniques of impedance-matching and reflection-cancelling, the open-stopbands at broadside are suppressed. Then the main beam of the proposed LWA can scan from backward to forward through broadside when frequency changes. Moreover, a tri-band application can be achieved in the dual-beam antenna by optimization of the second periodic structure. The measured results validate that the proposed SIW LWA has three operating frequency bands. In band 1 from 8.6 to 9.2 GHz, there is one beam scanning from 42° to 71° in the forward, in band 2 from 10 to 12 GHz, there is one beam scanning from -40° to 4° in the backward, and in band 3 from 12.5 to 15 GHz, there is a dual-beam scanning from -55° to 54° including broadside direction, which show good agreements with the simulated results.

In this paper, the Doppler frequency shift-based localization problem in the presence of sensor location errors is addressed. Based on the measurement model, we present two methods, an explicit solution and a semidefinite relaxation (SDR) technique, to estimate the position of the stationary source. In the two proposed algorithms, the non-accurate information on sensor position and velocity is considered. In the former algorithm, based on two best linear unbiased estimator, an explicit solution of the source position can be obtained, whereas in the latter one, the SDR technique is applied to relax the original maximum likelihood estimation into a convex semidefinite programming problem, which provides accurate estimate without postprocessing. Compared with the methods where the sensor location errors are not taken into consideration, the proposed algorithms are able to achieve a more accurate localization result. Simulations verify a better performance of these two proposed algorithms.