73 GHz Wideband Millimeter-Wave Foliage and Ground Reflection Measurements and Models

This paper presents 73 GHz wideband outdoor foliage and ground reflection measurements. Propagation measurements were made with a 400 Megachip-per-second sliding correlator channel sounder, with rotatable 27 dBi (7 degrees half- power beamwidth) horn antennas at both the transmitter and receiver, to study foliage-induced scattering and de-polarization effects, to assist in developing future wireless systems that will use adaptive array antennas. Signal attenuation through foliage was measured to be 0.4 dB/m for both co- and cross-polarized antenna configurations. Measured ground reflection coefficients for dirt and gravel ranged from 0.02 to 0.34, for incident angles ranging from 60 degrees to 81 degrees (with respect to the normal incidence of the surface). These data are useful for link budget design and site-specific (ray-tracing) models for future millimeter-wave communication systems.Comment: 6 pages, 4 figures, 2015 IEEE International Conference on Communications (ICC), ICC Workshop

28 GHz and 73 GHz Millimeter-Wave Indoor Propagation Measurements and Path Loss Models

This paper presents 28 GHz and 73 GHz millimeter- wave propagation measurements performed in a typical office environment using a 400 Megachip-per-second broadband sliding correlator channel sounder and highly directional steerable 15 dBi (30 degrees beamwidth) and 20 dBi (15 degrees beamwidth) horn antennas. Power delay profiles were acquired for 48 transmitter-receiver location combinations over distances ranging from 3.9 m to 45.9 m with maximum transmit powers of 24 dBm and 12.3 dBm at 28 GHz and 73 GHz, respectively. Directional and omnidirectional path loss models and RMS delay spread statistics are presented for line-of-sight and non-line-of-sight environments for both co- and cross-polarized antenna configurations. The LOS omnidirectional path loss exponents were 1.1 and 1.3 at 28 GHz and 73 GHz, and 2.7 and 3.2 in NLOS at 28 GHz and 73 GHz, respectively, for vertically-polarized antennas. The mean directional RMS delay spreads were 18.4 ns and 13.3 ns, with maximum values of 193 ns and 288 ns at 28 GHz and 73 GHz, respectively.Comment: 7 pages, 9 figures, 2015 IEEE International Conference on Communications (ICC), ICC Workshop

Applying Corpus-based Genre Analysis into the Teaching of Academic Chinese Writing

With an increasing number of international students coming to China for higher education, the learning needs of academic Chinese increased sharply. However, Chinese for Academic Purposes (CAP) is still in its infancy in both academic research and teaching practice. As a result, students lack the support for their academic Chinese skills and encounter difficulties according to their feedback. Meanwhile, the studies on English for Academic Purposes (EAP) pedagogy are fruitful. Among all the pedagogies, corpus-based instruction with genre analysis were found to be an effective approach in improving students’ EAP writing abilities. This study thus applied corpus-based genre analysis teaching approach to CAP teaching and examined the effectiveness. Through the construction and analysis of a specific corpus, this paper first investigated the move structure and high-frequency words and expressions of Chinese research article (RA) abstracts in the discipline of Economics and Management Science. Afterwards, a mini learning corpus was compiled for students’ exploration. The learning materials and sample tasks were introduced and data were collected from students’ feedback and writing samples before and after the teaching intervention. The results revealed that, firstly, the conventional move structure of Chinese RA abstracts in Economics and Management Science was I-MR-D, which is similar to English RA abstracts. Method and Results are two conventional moves. Second, corpus-based genre analysis can partially improve students’ performances in academic writing. After the teaching intervention, students’ awareness of text structure and the use of academic Chinese expressions improved noticeably. Though based on a small sample size, the research findings contribute towards the understanding of linguistic conventions of Chinese RA abstracts. Moreover, the materials and pedagogy used in this project shed new light on the instruction of Chinese writing as well as CAP curriculum development

Acoustic emission source location method and experimental verification for structures containing unknown empty areas

Acoustic emission (AE) localization plays an important role in the prediction and control of potential hazardous sources in complex structures. However, existing location methods have less discussion on the presence of unknown empty areas. This paper proposes an AE source location method for structures containing unknown empty areas (SUEA). Firstly, this method identifies the shape, size, and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE arrivals. Then, the unknown AE source can be located considering the identified empty areas. The lead break experiments were performed to verify the effectiveness and accuracy of the proposed method. Five specimens were selected containing empty areas with different positions, shapes, and sizes. Results show the average location accuracy of the SUEA increased by 78% compared to the results of the existing method. It can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels, bridges, railroads, and caves in practical engineering

Rethinking IoU-based Optimization for Single-stage 3D Object Detection

Since Intersection-over-Union (IoU) based optimization maintains the consistency of the final IoU prediction metric and losses, it has been widely used in both regression and classification branches of single-stage 2D object detectors. Recently, several 3D object detection methods adopt IoU-based optimization and directly replace the 2D IoU with 3D IoU. However, such a direct computation in 3D is very costly due to the complex implementation and inefficient backward operations. Moreover, 3D IoU-based optimization is sub-optimal as it is sensitive to rotation and thus can cause training instability and detection performance deterioration. In this paper, we propose a novel Rotation-Decoupled IoU (RDIoU) method that can mitigate the rotation-sensitivity issue, and produce more efficient optimization objectives compared with 3D IoU during the training stage. Specifically, our RDIoU simplifies the complex interactions of regression parameters by decoupling the rotation variable as an independent term, yet preserving the geometry of 3D IoU. By incorporating RDIoU into both the regression and classification branches, the network is encouraged to learn more precise bounding boxes and concurrently overcome the misalignment issue between classification and regression. Extensive experiments on the benchmark KITTI and Waymo Open Dataset validate that our RDIoU method can bring substantial improvement for the single-stage 3D object detection.Comment: Accepted by ECCV2022. The code is available at https://github.com/hlsheng1/RDIo

Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol) sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra, thermogravimetry (TGA) and differential scanning calorimetry (DSC) curves. Scanning Electron Microscopy (SEM) observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering