A Simulation Way to Investigate the Reason for Congestion in Urban——A Case Study in Hohhot China

In the case of high density traffic flow, traditional traffic data statistical analysis methods, which not only have certain errors and lead to inaccurate data, but also have many limitations such as labor consumption, can no longer meet the demand for traffic analysis. Drones for traffic data, based on an aerial bird\u27s-eye view, no offset, and error-free complete statistics of urban road shooting section of all data, while greatly reducing cost consumption. A multi-dimensional simulation model is established for the UAV data to the Hohhot central urban area\u27s road simulation platform. This project will test and explore multidimensional data in the simulation platform to investigate the congestion problem in Hohhot\u27s central city, as well as motor vehicle driving characteristics, non-motor vehicle driving behavior, road setting design, and other aspects, and provide optimization solutions for data-driven intelligent traffic control and management.https://digitalcommons.odu.edu/gradposters2023_engineering/1005/thumbnail.jp

Personalized Adaptive Meta Learning for Cold-start User Preference Prediction

A common challenge in personalized user preference prediction is the cold-start problem. Due to the lack of user-item interactions, directly learning from the new users' log data causes serious over-fitting problem. Recently, many existing studies regard the cold-start personalized preference prediction as a few-shot learning problem, where each user is the task and recommended items are the classes, and the gradient-based meta learning method (MAML) is leveraged to address this challenge. However, in real-world application, the users are not uniformly distributed (i.e., different users may have different browsing history, recommended items, and user profiles. We define the major users as the users in the groups with large numbers of users sharing similar user information, and other users are the minor users), existing MAML approaches tend to fit the major users and ignore the minor users. To address this cold-start task-overfitting problem, we propose a novel personalized adaptive meta learning approach to consider both the major and the minor users with three key contributions: 1) We are the first to present a personalized adaptive learning rate meta-learning approach to improve the performance of MAML by focusing on both the major and minor users. 2) To provide better personalized learning rates for each user, we introduce a similarity-based method to find similar users as a reference and a tree-based method to store users' features for fast search. 3) To reduce the memory usage, we design a memory agnostic regularizer to further reduce the space complexity to constant while maintain the performance. Experiments on MovieLens, BookCrossing, and real-world production datasets reveal that our method outperforms the state-of-the-art methods dramatically for both the minor and major users.Comment: Preprint Versio

Research on the coupled support technology of a composite rock beam-retained roadway roof under close coal seams

IntroductionThe technology of gob-side entry retaining without coal pillars in close (distance) coal seams is still immature, and the roof control and support technology in this case is not perfect.MethodsIn this paper, the coupled support technology of a composite rock beam roof under close coal seams is systematically studied by using theoretical analysis, numerical simulation and field test.ResultsBoth the floor slip calculation results and numerical simulations indicate that the vertical failure depth in the plastic zone of the #8 coal seam has not penetrated the roof of the #9 coal seam after mining, which is consistent with the field electronic imaging results. A theoretical formula for a composite rock beam model anchored by high-prestressed anchor cables was derived, and a formula for the optimal spacing of anchor cables under noncompressive shear failure of the roof was obtained. Identification of the internal stress hazard region of the rock beam provides a basis for determining the locations of vertical support. Through numerical simulation of different support schemes, including roof cutting, arrangement of high-prestressed anchor cables, and setting up of vertical supports, roof cutting was found to effectively reduce the stress of supporting structure and roof pressure. Setting up of vertical supports can reduce the roof convergence by 25.2%, and coupling with anchor cables can reduce the convergence by more than 49.1%. The feasibility of this support scheme was verified through field tests, with a maximum convergence of 99 mm between the roof and floor.DiscussionThis two-way verification approach, in which the damage degree of the roof of a close coal seam is analyzed through multiple means, targeted support plans are proposed, the support mechanisms are explored, and feedback is conducted through field tests, plays a certain guiding role in solving roof control of the gob-side entry retaining under similar geological conditions

Earthquake-Induced Stress Amplification and Rock Fragmentation within a Deep-Seated Bedding Fault: Case Study of the Daguangbao Landslide Triggered by the 2008 Wenchuan Earthquake (Ms=8.0)

AbstractThe 2008 Wenchuan Ms 8.0 earthquake triggered the Daguangbao (DGB) landslide, of which the shear surface belongs to a thrust bedding fault 400 m below the carbonate slope. After the landslide, a 1.8 km-long inclined sliding face (0.3 km2) was exposed in the south source area. By using shaking table test, the contributions of the fault to the landslide sliding have been studied in this paper. The bedding fault in the test model is simplified as a weak layer with small elasticity and the carbonate layers as a hard layer with high elastic modulus, which is 296 times the weak one. The test records larger displacement amplitude in the upper hard layer than that in the lower one and larger pressure amplitude in the weak layer than that in the hard ones. We ascribed the stress amplification in the weak layer to time delay of shaking wave as wave velocity in the weak layer is only 1/15 of that in the hard layers. Such time delay gives rise to phase differences between the hard layers during shaking. The compressive stress amplification occurs in the weak layer when the upper hard layer moves downwards relative to the lower one; otherwise, tensile stress amplification occurs. It is suggested that this kind of stress amplification triggered an extensive fragmentation of the bedding fault rock mass during the Wenchuan earthquake, which can be verified by a good deal of gentle-dip and steep-dip cracks observed on site. It is proposed that stress amplification had caused a fast dropping of shear strength in the bedding fault to enhance the suddenness of DGB landslide initiation

Downregulation of hypoxia-inducible factor-1α by RNA interference alleviates the development of collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is the most common type of autoimmune arthritis. Hypoxia-inducible factor-1α (HIF-1α) as a transcription factor in response to hypoxia suggests that it could be a potential therapeutic target for the treatment of RA. In this study, we assessed whether the HIF pathway blockade attenuates the manifestations of RA in the collagen-induced arthritis (CIA) rat model. We constructed a short hairpin RNA (shRNA) lentiviral expression vector targeting HIF-1α (pLVX-shRNA-HIF-1α) and to achieve HIF-1α RNA interference. Quantitative RT-PCR, immunofluorescence staining, and western blot were used to detect the expressions of HIF-1α, vascular endothelial growth factor (VEGF), phsopho (p)-p65, and p-IКBɑ mRNA and protein, respectively. Micro-computed tomography was used to investigate joint morphology at different time points after CIA induction. Moreover, enzyme-linked immunosorbent assay (ELISA) was used to monitor the expression of inflammatory cytokines. In vitro analyses revealed that pLVX-shRNA-HIF-1α effectively inhibited the expression of HIF-1α and VEGF and led to the activation of p-65 and p-IКBɑ, as well as decreased proinflammatory cytokine expression in cell culture. Inhibition of HIF-1α in rats decreased signs of a systemic inflammatory condition, together with decreased pathological changes of RA. Moreover, downregulation of HIF-1α expression markedly reduced the synovitis and angiogenesis. In conclusion, we have shown that pharmacological inhibition of HIF-1 may improve the clinical manifestations of RA