Hybrid Transceiver Optimization for Multi-Hop Communications

Multi-hop communication with the aid of large-scale antenna arrays will play a vital role in future emergence communication systems. In this paper, we investigate amplify-and-forward based and multiple-input multiple-output assisted multi-hop communication, in which all nodes employ hybrid transceivers. Moreover, channel errors are taken into account in our hybrid transceiver design. Based on the matrix-monotonic optimization framework, the optimal structures of the robust hybrid transceivers are derived. By utilizing these optimal structures, the optimizations of analog transceivers and digital transceivers can be separated without loss of optimality. This fact greatly simplifies the joint optimization of analog and digital transceivers. Since the optimization of analog transceivers under unit-modulus constraints is non-convex, a projection type algorithm is proposed for analog transceiver optimization to overcome this difficulty. Based on the derived analog transceivers, the optimal digital transceivers can then be derived using matrix-monotonic optimization. Numeral results obtained demonstrate the performance advantages of the proposed hybrid transceiver designs over other existing solutions.Comment: 32 pages, 6 figures. This manuscript has been submitted to IEEE Journal on Selected Areas in Communications (special issue on Multiple Antenna Technologies for Beyond 5G

Characterizing Manure and Litter Properties and Their Carbon Dioxide Production in an Aviary Laying-Hen Housing System

Contribution of carbon dioxide (CO2) production from manure or litter can be significant relative to animal metabolic CO2 production in housing systems with less frequent excretion removal. Such CO2 contribution should be accounted for in order to improve the accuracy of estimating building ventilation rate (VR) and animal bioenergetics based on CO2 mass balance. The objective of this study was to investigate the thermal conditions (temperature and relative humidity, or RH), production, moisture content (MC), and CO2 production of laying-hen manure on collection belts and on litter in an aviary house. Hens spent about 15.25 h day-1 in the aviary colony where their manure was deposited on the belts, and the remaining 8.75 h day-1 on the litter floor where manure was deposited on belt or litter. Manure belts were operated 1/3 of their length each day. Results show that temperature and RH were, respectively, 1.8 ± 9.3˚C (mean ± standard deviation) and 79 ± 14% for ambient air, 18.5 ± 1.7˚C and 76 ± 16% for air near manure on belt, and 19.8 ± 1.5˚C and 80 ± 17% for air near the litter. The overall daily manure production was 35.8 ± 1.4 g hen-1 day-1 on dry basis, with 90.9% deposited on manure belt and 9.1% on litter floor. MC of manure on belt was 66.4 ± 5.8%, which was significantly higher than 14.6 ± 2.4% for the litter. The combined moisture production from manure on belt and litter was estimated to be 22.6 g day-1 hen-1. The CO2 production from as-is manure was 0.10 ± 0.06 ml s-1 kg-1 (or 0.32 ± 0. 20 ml s-1 kg-1 on dry basis), whereas CO2 production from as-is litter was much lower, 0.02 ± 0.02 ml s-1 kg-1 (or 0.03 ± 0.02 ml s-1 kg-1 on dry basis). Without litter removal, CO2 production from manure and litter could amount to as high as 8.1% of the hen’s respiration CO2 at 60 week of age. This potentially significant contribution should be considered when estimating VR or animal bioenergetics using CO2 mass balance method in aviary housing systems

Efficient Fully Convolution Neural Network for Generating Pixel Wise Robotic Grasps With High Resolution Images

This paper presents an efficient neural network model to generate robotic grasps with high resolution images. The proposed model uses fully convolution neural network to generate robotic grasps for each pixel using 400 $\times$ 400 high resolution RGB-D images. It first down-sample the images to get features and then up-sample those features to the original size of the input as well as combines local and global features from different feature maps. Compared to other regression or classification methods for detecting robotic grasps, our method looks more like the segmentation methods which solves the problem through pixel-wise ways. We use Cornell Grasp Dataset to train and evaluate the model and get high accuracy about 94.42% for image-wise and 91.02% for object-wise and fast prediction time about 8ms. We also demonstrate that without training on the multiple objects dataset, our model can directly output robotic grasps candidates for different objects because of the pixel wise implementation.Comment: Submitted to ROBIO 201

Ternary Bismuthide SrPtBi2: Computation and Experiment in Synergism to Explore Solid-State Materials

A combination of theoretical calculation and the experimental synthesis to explore the new ternary compound is demonstrated in the Sr-Pt-Bi system. Since Pt-Bi is considered as a new critical charge-transfer pair for superconductivity, it inspired us to investigate the Sr-Pt-Bi system. With a thorough calculation of all the known stable/metastable compounds in the Sr-Pt-Bi system and crystal structure predictions, the thermodynamic stability of hypothetical stoichiometry, SrPtBi2, is determined. Followed by the high-temperature synthesis and crystallographic analysis, the first ternary bismuthide in Sr-Pt-Bi, SrPtBi2 was prepared and the stoichiometry was confirmed experimentally. SrPtBi2 crystallizes in the space group Pnma (S.G. 62, Pearson Symbol oP48), which matches well with theoretical prediction using an adaptive genetic algorithm (AGA). Using first-principles calculations, we demonstrate that the orthorhombic structure has lower formation energies than other 112 structure types, such as tetragonal BaMnBi2 (CuSmP2) and LaAuBi2 (CuHfSi2) structure types. The bonding analysis indicates the Pt-Bi interactions play a critical role in structural stability. The physical properties measurements show the metallic properties with low electron-phonon interactions at the low temperature, which agrees with the electronic structure assessment.Comment: 12 pages, 7 figure