23 research outputs found

    FreeNoise: Tuning-Free Longer Video Diffusion via Noise Rescheduling

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    With the availability of large-scale video datasets and the advances of diffusion models, text-driven video generation has achieved substantial progress. However, existing video generation models are typically trained on a limited number of frames, resulting in the inability to generate high-fidelity long videos during inference. Furthermore, these models only support single-text conditions, whereas real-life scenarios often require multi-text conditions as the video content changes over time. To tackle these challenges, this study explores the potential of extending the text-driven capability to generate longer videos conditioned on multiple texts. 1) We first analyze the impact of initial noise in video diffusion models. Then building upon the observation of noise, we propose FreeNoise, a tuning-free and time-efficient paradigm to enhance the generative capabilities of pretrained video diffusion models while preserving content consistency. Specifically, instead of initializing noises for all frames, we reschedule a sequence of noises for long-range correlation and perform temporal attention over them by window-based function. 2) Additionally, we design a novel motion injection method to support the generation of videos conditioned on multiple text prompts. Extensive experiments validate the superiority of our paradigm in extending the generative capabilities of video diffusion models. It is noteworthy that compared with the previous best-performing method which brought about 255% extra time cost, our method incurs only negligible time cost of approximately 17%. Generated video samples are available at our website: http://haonanqiu.com/projects/FreeNoise.html.Comment: Project Page: http://haonanqiu.com/projects/FreeNoise.html Code Repo: https://github.com/arthur-qiu/LongerCrafte

    The rise of urbanism and exchange network: reconstruction of a 4000-year local history of Xinjiang, northwestern China

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    Urbanization is one of the milestones in the development of human society. Many regions in the southern parts of ‘the old world’ demonstrating an early emergence of agriculture also witnessed the flourishing of some of the earliest cities. Recent, yet still sparse, archaeological evidence appears to indicate a relatively later time for early urbanism in central Eurasia. However, given its vital geographic location and cultural nexus between East and West, more attention should be paid to the sedentary communities and their cities in oases amid the vast droughty desert, particularly in light of the rapidly increasing number of publications on early pastoralism and related communication routes along mountain chains and rivers. This study reveals the trajectory of urbanization and its role in the establishment of an exchange network in Xinjiang’s oasis region via reconstruction of the chronological sequence of the local societal history of the Baiyang River Basin along the southern piedmont of the Eastern Tianshan Mountains. A thorough archaeological investigation and refined radiocarbon dating programme was carried out and coupled with information from historical documentation within a Bayesian statistical framework. The results indicate three pulses of local urbanization during: the Early Iron Age, Tang–Yuan period, and Qing Dynasty, respectively. Combining this with evidence from other parts of Xinjiang, we re-evaluate the role of oasis urbanism in the promotion of trans-regional exchange

    Vegetation history and its links to climate change during the last 36 ka in arid Central Asia: Evidence from a loess-paleosol sequence in the Eastern Ili Valley

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    Detailed vegetation history response to complex influencing factors of arid Central Asia (ACA) is crucial to understanding ecological sustainability. Here, we present the first pollen record in the Ili Valley during the Last Glacial Maximum (LGM) using the Jirentai (JRT) loess-paleosol sequence. Combining the results of multi-climate proxies and optically stimulated luminescence (OSL) dating, we aim to reconstruct the vegetative response to climate change during the last 36 ka. Our results show that rapid loess accumulation in the JRT section began in the Late MIS3 (Marine isotope stage 3), and a thin paleosol layer developed in the Late LGM and Post Glacial. The pollen concentrations in the loess are significantly lower than in the paleosol, but the pollen assemblages are richer. Artemisia and Asteraceae are the dominant non-arboreal types in the loess, and abundant arboreal species are present (e.g., Pinus, Picea, Quercus, Betulaceae). The percentage of Artemisia remains high in the paleosol, and typical drought-tolerant plants are an important component (e.g., Orthomorphic, Ephedra). We suggest that the rich variety of pollen in loess is transported by frequent and intense dust activities, and these pollen may come from regional vegetation. Less diverse pollen assemblages in paleosol respond to the vegetation surrounding the JRT section. The vegetation history obtained from the JRT section shows that the lowlands of the Ili Valley were typical desert or desert-steppe vegetation for the past 36 ka. The surrounding mountains are dominated by Pinus and Picea forests. During the Early LGM, vegetation conditions deteriorated in both of mountainous and lowland. The above phenomena coincide with the pollen records from lakes in the ACA. Our results further suggest that mountain forests reappear and the lowland environment improves in response to increased insolation in the Northern Hemisphere at high latitudes in the Late LGM. This point in time is earlier by about 5–10 ka compared to previous records. We attribute it to the fact that pollen assemblages from the loess-paleosol sequence are more sensitive to vegetation and climate change during the transition from the glacial to interglacial and propose a simple model to characterize them

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    On the Exploration of Social Development during a Historical Period in the Eastern Tienshan Mountains via Archaeological and Geopolitical Perspectives

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    Natural and social environment changes have played important roles in social evolution in different times and spaces. Geopolitical change, in particular, might play a decisive role in social evolution during historical periods. The eastern Tienshan Mountains was a transportation hub for communication between the East and the West, where the natural environment is fragile and the social environment has been complex during the historical period. However, geopolitical change and its impact on local social development remain unclear due to fragmented historical records and limited studies. This study investigates the spatiotemporal variations of military facilities in the Hami region, and compares historical documents and archaeological and paleoclimate records to discuss geopolitical changes and social evolution during the historical period in the eastern Tienshan Mountains. A total of 84 visible organic remains from 38 historic beacon towers and 8 dak sites in the Hami region of the eastern Xinjiang Uygur Autonomous Region, northwestern China, were collected and the radiocarbon (14C) dates of these ruins were systematically determined with accelerator mass spectrometry. The dating results show that these sites were mainly built during two major periods: ca. 600–900 cal AD and ca. 1600–1950 cal AD, which roughly correspond to the Tang Dynasty (618–907 AD) and the Qing Dynasty (1636–1912 AD) in ancient China. Human settlement intensity was high during the Han, Tang, and Qing dynasties, and relatively low when the area was controlled by nomadic or local regimes. This suggests that agricultural empires and nomadic/local regimes adopted different strategies for regional management. Climate change might have affected geopolitical patterns, which, in turn, profoundly influenced human activities and social evolution in the eastern Tienshan Mountains over the last two millennia. This study systematically reveals the spatiotemporal variations of beacon towers and dak ruins in the region through a large number of reliable direct 14C dating, it reveals the remarkable differences in human activities in the eastern Tienshan Mountains under different administrations, and it explores the influence of geopolitics and climate change on social evolution in the eastern Tienshan Mountains from a multidisciplinary perspective

    Dietary shift and social hierarchy from the Proto-Shang to Zhou Dynasty in the Central Plains of China

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    The Proto-Shang, the Shang and the Zhou dynasties (∼2000–221 BCE: Before Common Era) are key periods in the origin and evolution of ancient civilizations in China since the periods include the processes and mechanisms of social development in the Central Plains of China during the Bronze Age. However, human-environment interactions in the context of trans-Eurasia cultural exchange during that time are not well-understood. In this study, isotopic analysis and radiocarbon dating of human and animal bones from Xinancheng cemetery in southeast Shanxi Province are reported. It was deduced that, for the period ∼1000–800 BCE, humans buried in Xinancheng cemetery relied primarily on C _4 -based foods and upper-status individuals consumed more animal protein and probably C _3 crops. Also, considering the paleoclimate and other archaeological data of the Central Plains, the human diet and subsistence strategies changed significantly with more C _3 staples such as wheat being consumed during the Eastern Zhou (770–221 BCE), as evidenced by an increased intake of wheat by lower-status individuals and the development of a mixed wheat and millet agricultural system. It is argued that the socio-economic change around the late western Zhou-early eastern Zhou Dynasty occurred as a result of the necessity to adapt to the aggravation caused by climate deterioration and population pressures, factors which profoundly influenced the economic and lifestyle patterns in ancient China. The socio-economic system of the Eastern Zhou Dynasty displayed more resilience to climate change than that of earlier periods

    Vector characteristics and laws of electromagnetic radiation generated from coal rock fracture

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    The safe mining of coal and other resources is the key to guaranteeing energy security. With the continuous increase in mining intensity and depth, coal and gas outburst and other dynamic disasters pose a serious threat to the safe and efficient mining. As a real-time, non-contact, and highly precursor geophysical monitoring method, electromagnetic radiation (EMR) technology has played an important role in monitoring and warning of coal-rock dynamic disasters. Current research primarily focuses on scalar parameters, overlooking the spatial vector characteristics inherent in the electromagnetic field. Therefore, based on the principle of vector synthesis, the vector characteristics of fracture-induced electromagnetic signals were studied using a self-developed three-axis electromagnetic antenna. Electromagnetic signals on the three axes have obvious differences in the time domain, while the distribution in the frequency domain is relatively consistent. They can be regarded as the components of the e-lectromagnetic field in the three directions. Generated vector field is non-uniformly distributed around the specimen. The directional difference of signals can be used to characterize vectors. There is a clear correlation between the direction of the equivalent vector and the crack surface. The vector electromagnetic field results from combined effects of multiple microcracks. Multi frequency signals can be regarded as the superposition of electromagnetic effects generated by forced and damped oscillations of multiple dipoles in different directions and frequencies. On-site tests show that the use of electromagnetic vector characteristics can assist in identifying fault areas and hazard levels. The research results contribute to further revealing the spatio-temporal evolution of the fracture behavior throughout the entire fracture process. This can lay the foundation for the monitoring and early warning of coal-rock dynamic disasters in a non-contact, spatiotemporal and precise manner

    Analyzing the Synchronous Acoustic and Electric Response of Coal Burst Failure: Validation through the On-Site Application

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    The accurate monitoring and early warning of coal and rock dynamic disasters become challenging in complex geological environments. Mostly, the signal information contains interferences, which misguides the technician, and thus leads to inaccurate monitoring results. To reduce the influence of interference signals, the synchronous response of the acoustic emission (AE) and electromagnetic emission (EME) signals before the failure of coal specimens during uniaxial loading was investigated in this study. Additionally, the coupling relationship between M value, AE energy/AE ringing count per unit time, and the damage of coal is established, and the early warning index of AE and EME (R value) was computed and verified through the field investigations. The results show that a strong synchronization of the acoustoelectric signals occurs only after the specimen enters the strain strengthening area. The analysis of the obtained results showed that the M value of the AE-EME synchronous response signal represents a strong degree of damage occurring in the coal body, however, this is still subject to false alarms. In contrast, the analysis of the R value accurately helped in determining the damage evaluation, thus, it can be regarded as one of the precursors of the imminent failure of coal. With R > 1, the specimen is closed to the failure state, thereby dangerous regions are identified with a dense concentration of R > 1 events. The obtained R value index through on-site AE and EME monitoring corresponds closely with the stress distribution cloud map of the roadway. It is inferred that the anti-interference ability and the reliability of the R value index are stronger than the routine early warning indicators of the single-AE or EME energy

    Study on the Nonlinear Characteristics of EMR and AE during Coal Splitting Tests

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    Coal and rock dynamic disasters have been the main concern in underground engineering because these seriously threaten the safety of miners and industrial production. Aiming to improve the EMR and AE monitoring technology, the refined nonlinear characteristics of EMR and AE during coal splitting failure are studied using Hilbert-H and multifractal theory, and valuable information pertaining to coal fracture law contained in EMR and AE waveform was revealed. The results show that the EMR and AE of coal splitting failure are related to the process of coal crack propagation. They possess the same initiation time and frequency band, however, the signal duration of EMR is comparatively longer than AE, and the main frequency of AE is higher than EMR. The EMR of coal splitting failure has the same excitation source as AE; nonetheless, the excited forms display different behavior. In terms of signal duration, the distribution of EMR signal is relatively uniform, the proportion of large-signal is less, the amount of information is more than that of AE, and the multifractal characteristics are more complicated. During the coal splitting failure, AE is mainly generated in the process of wall vibration caused by crack propagation, while the generation of EMR includes piezoelectric effect, charge separation, free charge vibration, charge neutralization and other processes, making EMR more complicated than AE and has a relatively low frequency. The research provides an effective method for studying nonlinear refinement characteristics of coal EMR and AE, and can provide an important basis for the study of the mechanism of EMR generation

    Study on the Nonlinear Characteristics of EMR and AE during Coal Splitting Tests

    No full text
    Coal and rock dynamic disasters have been the main concern in underground engineering because these seriously threaten the safety of miners and industrial production. Aiming to improve the EMR and AE monitoring technology, the refined nonlinear characteristics of EMR and AE during coal splitting failure are studied using Hilbert-H and multifractal theory, and valuable information pertaining to coal fracture law contained in EMR and AE waveform was revealed. The results show that the EMR and AE of coal splitting failure are related to the process of coal crack propagation. They possess the same initiation time and frequency band, however, the signal duration of EMR is comparatively longer than AE, and the main frequency of AE is higher than EMR. The EMR of coal splitting failure has the same excitation source as AE; nonetheless, the excited forms display different behavior. In terms of signal duration, the distribution of EMR signal is relatively uniform, the proportion of large-signal is less, the amount of information is more than that of AE, and the multifractal characteristics are more complicated. During the coal splitting failure, AE is mainly generated in the process of wall vibration caused by crack propagation, while the generation of EMR includes piezoelectric effect, charge separation, free charge vibration, charge neutralization and other processes, making EMR more complicated than AE and has a relatively low frequency. The research provides an effective method for studying nonlinear refinement characteristics of coal EMR and AE, and can provide an important basis for the study of the mechanism of EMR generation
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