Ever since the deployment of the first-generation of mobile telecommunications, wireless communication technology has evolved at a dramatically fast pace over the past four decades. The upcoming ...fifth-generation (5G) holds a great promise in providing an ultra-fast data rate, a very low latency, and a significantly improved spectral efficiency by exploiting the millimeter-wave spectrum for the first time in mobile communication infrastructures. In the years beyond 2030, newly emerged data-hungry applications and the greatly expanded wireless network will call for the sixth-generation (6G) communication that represents a significant upgrade from the 5G network - covering almost the entire surface of the earth and the near outer space. In both the 5G and future 6G networks, millimeter-wave technologies will play an important role in accomplishing the envisioned network performance and communication tasks. In this paper, the relevant millimeter-wave enabling technologies are reviewed: they include the recent developments on the system architectures of active beamforming arrays, beamforming integrated circuits, antennas for base stations and user terminals, system measurement and calibration, and channel characterization. The requirements of each part for future 6G communications are also briefly discussed.
Aeration is an important factor to regulate composting efficiency and nitrogen loss. This study is aimed to compare the effects of different aeration modes (continuous and intermittent) and aeration ...rate on nitrogen conversion and bacterial community in composting from dehydrated sludge and corn straw. Results showed that the intermittent aeration mode at same aeration volume was superior to the continuous aeration mode in terms of NH
emission reduction, nitrogen conversion and germination index (GI) improvement. Intermittent aeration mode with 1200 L/h (aeration 5 min, stop 15 min) K5T15 (V1200) and 300 L/h of continuous aeration helped to the conservation of nitrogen fractions and accelerate the composting process. However, it was most advantageous to use 150 L/h of continuous aeration to reduce NH
emission and ensure the effective composting process. The aeration mode K5T15 (V1200) showed the fastest temperature rise, the longer duration of thermophilic stage and the highest GI (95%) in composting. The cumulative NH
emission of intermittent aeration mode was higher than continuous aeration mode. The cumulative NH
emission of V300 was 23.1% lower than that of K5T15 (V1200). The dominant phyla in dehydrated sludge and corn straw composting were Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. The dominant phylum in the thermophilic stage was Firmicutes (49.39%~63.13%), and the dominant genus was
(18.62%~30.16%). The relative abundance of Firmicutes was greater in the intermittent aeration mode (63.13%) than that in the continuous aeration mode (57.62%), and
was dominant in composting with lower aeration rate and the lowest NH
emission. This study suggested that adjustment to the aeration mode and rate could affect core bacteria to reduce the nitrogen loss and accelerate composting process.
This Letter presents a miniaturised multi-channel millimetre-wave filter bank implemented by stripline and substrate integrated waveguide (SIW). Since the orthogonal transverse electric mode and ...transverse electromagnetic mode can coexist in the same hybrid structure cavity and be transmitted almost without mutual interference, embedding stripline into SIW to miniaturise the size of the filter bank is achievable. A prototype composed of four bandpass filter units working at X-band is designed, fabricated and tested. Measurement results show that the proposed device has four independent channels with a good quality of bandpass filtering and the isolation among ports of different filter units are relatively high. The proposed prototype has 39.5% volume reduction than traditional stacking structure as well as good scalability, which has broad prospects in the application of next-generation wireless communication system.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•The protagonist with new definition is efficient to capture video emotional content.•Temporal information is useful to improve the emotion recognition performance.•A novel keyframe selecting ...strategy can extract typical protagonist-based frames.•Combining optical flow and CNN can extract discriminative features in time domain.•The proposed system can recognize the video emotion intelligently and automatically.
Extracting an effective representation to analyze affection in videos is an inherent challenge. To address this problem, we present a novel emotion recognition system that can intelligently analyze and automatically recognize video emotions. We observe that most of the emotions in a video are closely related to the roles, especially those of the protagonist, which motivates us to explore how to utilize the protagonist’s information to help recognize video emotions. By analyzing the traits of the protagonists, we suggest a new solution to detect the protagonists to adapt not only to the whole video but also to a video clip. Moreover, a new keyframe selection strategy based on the protagonist is designed to select a set of representative frames from video clips. Furthermore, the scale invariant feature transform (SIFT) features matrix, built from each keyframe, is fed into a convolutional neural network (CNN) to learn the discriminative representations, which makes the CNN and local features complement each other. Considering that emotions are usually continuous, we introduce temporal information into the CNN by using optical flow images. Additionally, we extract some handcrafted visual and audio features as a supplement. Finally, all the features, including the features learned from the CNN and the handcrafted features, are fused and input into a support vector machine (SVM) and a support vector regression (SVR) for video emotion recognition. The proposed system is validated on a public dataset (LIRIS-ACCEDE) and a new dataset (PMSZU). The experimental results demonstrate the promising performance of the proposed system, which achieves better performance than the compared methods. Our designed system for recognizing video emotions could also facilitate the development of similar video expert systems, for applications such as video recommendations, video classification and video retrieval.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents a novel methodology to emulate dynamic channels within the multi-probe anechoic chamber (MPAC) framework for over-the-air (OTA) testing. The approach integrates time-domain ...clustering and multi-objective optimization algorithms to emulate dynamic channels precisely. Simulations and experimental validation have been provided to demonstrate the effectiveness of the proposed method, where power-angular-spectrum similarity percentage (PSP) values surpassing 87% can be consistently achieved. The time domain clustering and probe selection technique significantly contribute to the reduction of emulation complexity by compressing both temporal and spatial domains of the channel. Consequently, this strategy enhances the feasibility of system performance testing in dynamic propagation scenarios within the MPAC, and offers a novel framework for the emulation of dynamic channels in MPAC OTA testing.
This Letter presents a novel deep learning approach for optimising the receiver performance with respect to the error vector magnitude (EVM) metric, which was verified and evaluated by applying it to ...a self-developed proprietary vector signal analyser (VSA). A four-layer neural network was built and trained to estimate and correct the systematic error of the VSA receiver by using a calibrated commercially available vector signal generator as the training source. Experimental results show that the EVM performance of the self-developed VSA is improved and approaches that of a state-of-the-art VSA.
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This letter presents a novel probe selection method for multiple-input-multiple-output (MIMO) over-the-air (OTA) testing. It can effectively reduce the number of probes used in anechoic chamber, ...which further reduces the ports of the channel emulator. Two basic channel models are used to validate the performance of this method. The simulation results demonstrate that it can reconstruct the channel environment around the device-under-test in a multiprobe anechoic chamber with high accuracy. In addition, the impact of different probe configuration setups on the accuracy of test results are discussed.
This letter proposes a novel four-dimensional multiprobe anechoic chamber (4D-MPAC) method for emulating time-domain nonstationary channel models of over-the-air testing. The proposed method adds ...time dimension to the 3D-MPAC system, so that the channel model with spatial parameters changing over time can be emulated. In addition, 4-D power angular spectrum similarity percentage (4D-PSP) as a figure of merit to evaluate the accuracy of the channel reconstruction is proposed for the first time. Based on the 4D-PSP, genetic algorithm is designed to reduce the number of active probes and testing cost. Furthermore, a dynamic motion scenario in a street is modeled by ray tracing simulation, where the time-domain nonstationary channel model is reconstructed by the proposed method with a small number of probes.
AbstractChina National Offshore Oil Corporation (CNOOC) currently is developing a mat-supported wellhead production platform concept as an alternative solution to conventional jacket platforms in ...shallow-water oil fields. The platform is towed to the site with the mat foundation elevated. The mat then is lowered and embedded in the seabed as the hull is jacked out of the water. Steel pipe piles subsequently are driven through the tubular legs of the platform. After grouting the connection, the pile foundations provide permanent support for the platform. The mat foundation therefore provides only temporary support to the platform. This paper presents a case study focusing on the installation behavior of the mat foundation in a soft soil site as part of the platform concept development and suitability evaluation. The study determined (1) the expected penetration depth under the platform’s self-weight considering its irregular geometry and soft over stiff clay stratigraphy; (2) the target center of gravity to achieve even penetration and the potential for tilt development in the case of offset from the target position; (3) the effectiveness of using ballast tanks to correct the tilt; and (4) settlement after the installation due to dissipation of pore pressure and creep. Advanced large-deformation finite-element simulations featuring a strain softening soil model and analytical analyses were performed. A dedicated lab testing program geared was designed and executed to provide the necessary soil parameters for the analyses. This paper presents the techniques and considerations that were applied in this study and insights gained into the installation and subsequent postinstallation behavior of large-area mat foundations.
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