Task-Oriented Cross-System Design for Timely and Accurate Modeling in the Metaverse

In this paper, we establish a task-oriented cross-system design framework to minimize the required packet rate for timely and accurate modeling of a real-world robotic arm in the Metaverse, where sensing, communication, prediction, control, and rendering are considered. To optimize a scheduling policy and prediction horizons, we design a Constraint Proximal Policy Optimization(C-PPO) algorithm by integrating domain knowledge from relevant systems into the advanced reinforcement learning algorithm, Proximal Policy Optimization(PPO). Specifically, the Jacobian matrix for analyzing the motion of the robotic arm is included in the state of the C-PPO algorithm, and the Conditional Value-at-Risk(CVaR) of the state-value function characterizing the long-term modeling error is adopted in the constraint. Besides, the policy is represented by a two-branch neural network determining the scheduling policy and the prediction horizons, respectively. To evaluate our algorithm, we build a prototype including a real-world robotic arm and its digital model in the Metaverse. The experimental results indicate that domain knowledge helps to reduce the convergence time and the required packet rate by up to 50%, and the cross-system design framework outperforms a baseline framework in terms of the required packet rate and the tail distribution of the modeling error.Comment: This paper is accepted by IEEE Journal on Selected Areas in Communications, JSAC-SI-HCM 202

Functionalization of softwood kraft lignin for coating urea as highly efficient nitrogen fertilizer

An industrial softwood kraft lignin (SKL) was blended with polylactic acid (PLA) and used for complex coating of urea as nitrogen fertiliser. The coating was perfumed using a simple and cheap dip-coating technique. The lignin was pre-functionalised via esterification or Mannich reaction. Esterification rendered a lignin derivative with higher hydrophobicity, while the Mannich reaction introduced organically bound nitrogen onto the lignin derivative structure. It was found that the coating resulted in good attachment of the coating layer on the surface of urea pellets. The coating layer was very compact and the wall layer was rather homogeneous and well distributed. The urea coating not only constructed a physical barrier to delay urea dissolution (controlled release), but also supplied chemically slow-release, organically bound nitrogen and biological stabilisation effects. It was found that the Mannich reaction product (ManSKL/PLA) slowed down the urea release more than the PLA coating reference, taking approximately 1m000s or 6.7 times as lon

Functionalization of softwood kraft lignin for coating urea as highly efficient nitrogen fertilizer

An industrial softwood kraft lignin (SKL) was blended with polylactic acid (PLA) and used for complex coating of urea as nitrogen fertiliser. The coating was perfumed using a simple and cheap dip-coating technique. The lignin was pre-functionalised via esterification or Mannich reaction. Esterification rendered a lignin derivative with higher hydrophobicity, while the Mannich reaction introduced organically bound nitrogen onto the lignin derivative structure. It was found that the coating resulted in good attachment of the coating layer on the surface of urea pellets. The coating layer was very compact and the wall layer was rather homogeneous and well distributed. The urea coating not only constructed a physical barrier to delay urea dissolution (controlled release), but also supplied chemically slow-release, organically bound nitrogen and biological stabilisation effects. It was found that the Mannich reaction product (ManSKL/PLA) slowed down the urea release more than the PLA coating reference, taking approximately 1m000s or 6.7 times as lon

Spatial variability of soil organic matter and total nitrogen and the influencing factors in Huzhu County of Qinghai Province, China

The soil organic matter (SOM) and soil total nitrogen (STN) is a significant concern in Qinghai–Tibet Plateau, China. This study analysed the spatial distribution of SOM and STN and determined their influencing factors to support the conservation of cultivated soil and development of sustainable agricultural strategies in the Plateau. In total, 120 soil samples were collected from the 0–20-cm soil layer in Huzhu County, Qinghai Province. Traditional statistical and geostatistical methods were used to analyse the spatial distribution of SOM and STN; a geographical detector (GeoDetector)was used to explore the factors influencing the spatial variation. The SOM and STN concentrations were 6.92–44.57 and 0.52–2.54 g/kg, respectively. The Cokriging interpolation map showed a similar spatial distribution pattern for SOM and STN concentrations, which decreased from the northeast to southwest directions in the study area. GeoDetector results revealed that the three primary factors influencing the spatial variability of SOM and STN were soil type, annual accumulated precipitation and elevation, with their explanatory power ranging between 38.4% and 59.5%. Two-factor interactions enhanced the explanatory power of the spatial variability of SOM and STN. The research results provide a reference for conservation tillage and precision agriculture

Da xing an ling sen lin zi yuan diao cha bao gao

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