Static and dynamic finite element analysis of 304 stainless steel rod and wire hot continuous rolling process

Three-dimensional finite element models were developed to analyze 304 stainless steel rod and wire hot continuous rolling process with the help of MSC.Marc software. The entire 30-pass deformation process and the actual parameters of production line were taken into account. Static and dynamic procedures were used to study the continuous rolling process with the aid of the thermo-mechanical coupled FEM of elastic-plasticity. The properties of billets, such as deformation, temperature field and rolling force, were mainly discussed. The simulation results of temperature agree well with the measured values. Comparisons of the analysis results obtained using static implicit method and dynamic implicit method were presented. It is shown that static implicit procedure is more accurate than dynamic implicit procedure and is able to simulate the rolling process with a lower speed, such as a roughing mill. Whereas, dynamic analysis shows a higher efficiency than static analysis and is fit for simulating the rolling process with a higher speed, such as a finishing mill.

Downlink Resource Allocation for NOMA-Based Hybrid Spectrum Access in Cognitive Network

To solve the contradiction between limited spectrum resources and increasing communication demand,this paper proposes a wireless resource allocation scheme based on the Deep Q Network(DQN)to allocate radio resources in a downlink multi-user cognitive radio(CR)network with slicing.Secondary users(SUs)are multiplexed using non-orthogonal multiple access(NOMA).The SUs use the hybrid spectrum access mode to improve the spectral efficiency(SE).Considering the demand for multiple services,the enhanced mobile broadband(eMBB)slice and ultrareliable low-latency communication(URLLC)slice were established.The proposed scheme can maximize the SE while ensuring Quality of Service(QoS)for the users.This study established a mapping relationship between resource allocation and the DQN algorithm in the CR-NOMA network.According to the signal-to-interference-plusnoise ratio(SINR)of the primary users(PUs),the proposed scheme can output the optimal channel selection and power allocation.The simulation results reveal that the proposed scheme can converge faster and obtain higher rewards compared with the Q-Learning scheme.Additionally,the proposed scheme has better SE than both the overlay and underlay only modes.

User Scheduling and Slicing Resource Allocation in Industrial Internet of Things

Heterogeneous base station deployment enables to provide high capacity and wide area coverage.Network slicing makes it possible to allocate wireless resource for heterogeneous services on demand.These two promising technologies contribute to the unprecedented service in 5G.We establish a multiservice heterogeneous network model,which aims to raise the transmission rate under the delay constraints for active control terminals,and optimize the energy efficiency for passive network terminals.A policygradient-based deep reinforcement learning algorithm is proposed to make decisions on user association and power control in the continuous action space.Simulation results indicate the good convergence of the algorithm,and higher reward is obtained compared with other baselines.

Modeling and finite element analysis of rod and wire steel rolling process

Two thermomechanical coupled elastic-plastic finite element （FE） models were developed for predicting the 12-pass continuous rolling process of GCrl 5 rod and wire steel. The distances between stands in the proposed models were set according to the actual values, and the billets were shortened in the models to reduce the calculation time. To keep the continuity of simulation, a technique was developed to transfer temperature data between the meshes of different models in terms of nodal parameters by interpolation functions. The different process variables related to the rolling process, such as temperature, total equivalent plastic strain, equivalent plastic strain rate, and contact friction force, were analyzed. Also, the proposed models were applied to analyze the reason for the occurrence of an excessive spread in width. Meanwhile, it was also utilized to assess the influence of the roll diameter change on the simulated results such as temperature and rolling force. The simulated results of temperature are found to agree well with the measured results.

Cognitive RAN Slicing Resource Allocation Based on Stackelberg Game

The cognitive network has become a promising method to solve the spectrum resources shortage problem.Especially for the optimization of network slicing resources in the cognitive radio access network(RAN),we are interested in the profit of the mobile virtual network operator(MVNO)and the utility of secondary users(SUs).In cognitive RAN,we aim to find the optimal scheme for the MVNO to efficiently allocate slice resources to SUs.Since the MVNO and SUs are selfish and the game between the MVNO and SUs is difficult to reach equilibrium,we consider modeling this scheme as a Stackelberg game.Leveraging mathematical programming with equilibrium constraints(MPEC)and Karush-Kuhn-Tucker(KKT)conditions,we can obtain a single-level optimization problem,and then prove that the problem is a convex optimization problem.The simulation results show that the proposed method is superior to the noncooperative game.While guaranteeing the Quality of Service(QoS)of primary users(PUs)and SUs,the proposed method can balance the profit of the MVNO and the utility of SUs.

Toll-Like Receptor 4 Deficiency Causes Reduced Exploratory Behavior in Mice Under Approach-Avoidance Conflict

Abnormal approach-avoidance behavior has been linked to deficits in the mesolimbic dopamine（DA）system of the brain. Recently, increasing evidence has indicated that toll-like receptor 4（TLR4）, an important pattern-recognition receptor in the innate immune system,can be directly activated by substances of abuse, resulting in an increase of the extracellular DA level in the nucleus accumbens. We thus hypothesized that TLR4-dependent signaling might regulate approach-avoidance behavior. To test this hypothesis, we compared the novelty-seeking and social interaction behaviors of TLR4-deficient（TLR4^（-/-））and wild-type（WT） mice in an approach-avoidance conflict situation in which the positive motivation to explore a novel object or interact with an unfamiliar mouse was counteracted by the negative motivation to hide in exposed,large spaces. We found that TLR4^（-/-）mice exhibitedreduced novelty-seeking and social interaction in the large open spaces. In less stressful test apparatuses similar in size to the mouse cage, however, TLR4^（-/-）mice performed normally in both novelty-seeking and social interaction tests. The reduced exploratory behaviors under approachavoidance conflict were not due to a high anxiety level or an enhanced fear response in the TLR4^（-/-）mice, as these mice showed normal anxiety and fear responses in the open field and passive avoidance tests, respectively. Importantly,the novelty-seeking behavior in the large open field induced a higher level of c-Fos activation in the nucleus accumbens shell（NAc Sh） in TLR4^（-/-）mice than in WT mice. Partially inactivating the NAc Sh via infusion of GABA receptor agonists restored the novelty-seeking behavior of TLR4^（-/-）mice. These data suggested that TLR4 is crucial for positive motivational behavior under approach-avoidance conflict. TLR4-dependent activation of neurons in the NAc Sh may contribute to this phenomenon.