Smart prediction of liquefaction-induced lateral spreading

The prediction of liquefaction-induced lateral spreading/displacement(Dh)is a challenging task for civil/geotechnical engineers.In this study,a new approach is proposed to predict Dh using gene expression programming(GEP).Based on statistical reasoning,individual models were developed for two topographies:free-face and gently sloping ground.Along with a comparison with conventional approaches for predicting the Dh,four additional regression-based soft computing models,i.e.Gaussian process regression(GPR),relevance vector machine(RVM),sequential minimal optimization regression(SMOR),and M5-tree,were developed and compared with the GEP model.The results indicate that the GEP models predict Dh with less bias,as evidenced by the root mean square error(RMSE)and mean absolute error(MAE)for training(i.e.1.092 and 0.815;and 0.643 and 0.526)and for testing(i.e.0.89 and 0.705;and 0.773 and 0.573)in free-face and gently sloping ground topographies,respectively.The overall performance for the free-face topology was ranked as follows:GEP>RVM>M5-tree>GPR>SMOR,with a total score of 40,32,24,15,and 10,respectively.For the gently sloping condition,the performance was ranked as follows:GEP>RVM>GPR>M5-tree>SMOR with a total score of 40,32,21,19,and 8,respectively.Finally,the results of the sensitivity analysis showed that for both free-face and gently sloping ground,the liquefiable layer thickness(T_(15))was the major parameter with percentage deterioration(%D)value of 99.15 and 90.72,respectively.

Individual dynamics and local heterogeneity provide a microscopic view of the epidemic spreading

The COVID-19 pandemic has caused severe global disasters,highlighting the importance of understanding the details and trends of epidemic transmission in order to introduce efficient intervention measures.While the widely used deterministic compartmental models have qualitatively presented continuous “analytical” insight and captured some transmission features,their treatment usually lacks spatiotemporal variation.Here,we propose a stochastic individual dynamical(SID)model to mimic the random and heterogeneous nature of epidemic propagation.The SID model provides a unifying framework for representing the spatiotemporal variations of epidemic development by tracking the movements of each individual.Using this model,we reproduce the infection curves for COVID-19 cases in different areas globally and find the local dynamics and heterogeneity at the individual level that affect the disease outbreak.The macroscopic trend of virus spreading is clearly illustrated from the microscopic perspective,enabling a quantitative assessment of different interventions.Seemingly,this model is also applicable to studying stochastic processes at the “meter scale”,e.g.,human society’s collective dynamics.

Influence of network structure on spreading dynamics via tie range

There are various phenomena of malicious information spreading in the real society, which cause many negative impacts on the society. In order to better control the spreading, it is crucial to reveal the influence of network structure on network spreading. Motifs, as fundamental structures within a network, play a significant role in spreading. Therefore, it is of interest to investigate the influence of the structural characteristics of basic network motifs on spreading dynamics.Considering the edges of the basic network motifs in an undirected network correspond to different tie ranges, two edge removal strategies are proposed, short ties priority removal strategy and long ties priority removal strategy. The tie range represents the second shortest path length between two connected nodes. The study focuses on analyzing how the proposed strategies impact network spreading and network structure, as well as examining the influence of network structure on network spreading. Our findings indicate that the long ties priority removal strategy is most effective in controlling network spreading, especially in terms of spread range and spread velocity. In terms of network structure, the clustering coefficient and the diameter of network also have an effect on the network spreading, and the triangular structure as an important motif structure effectively inhibits the spreading.

Possible Cortical Spreading Depression Recorded Intraoperatively Following a Generalized Seizure: Illustrative Case

Background: We present a compelling case fitting the phenomenon of cortical spreading depression detected by intraoperative neurophysiological monitoring (IONM) following an intraoperative seizure during a craniotomy for revascularization. Cortical spreading depression (CSD, also called cortical spreading depolarization) is a pathophysiological phenomenon whereby a wave of depolarization is thought to propagate across the cerebral cortex, creating a brief period of relative neuronal inactivity. The relationship between CSD and seizures is unclear, although some literature has made a correlation between seizures and a cortical environment conducive to CSD. Methods: Intraoperative somatosensory evoked potentials (SSEPs) and electroencephalography (EEG) were monitored continuously during the craniotomy procedure utilizing standard montages. Electrophysiological data from pre-ictal, ictal, and post-ictal periods were recorded. Results: During the procedure, intraoperative EEG captured a generalized seizure followed by a stepwise decrease in somatosensory evoked potential cortical amplitudes, compelling for the phenomenon of CSD. The subsequent partial recovery of neuronal function was also captured electrophysiologically. Discussion: While CSD is considered controversial in some aspects, intraoperative neurophysiological monitoring allowed for the unique analysis of a case demonstrating a CSD-like phenomenon. To our knowledge, this is the first published example of this phenomenon in which intraoperative neurophysiological monitoring captured a seizure, along with a stepwise subsequent reduction in SSEP cortical amplitudes not explained by other variables.

An Important Spreading Event of the Neo-Tethys Ocean during the Late Jurassic and Early Cretaceous: Evidence from Zircon U-Pb SHRIMP Dating on Diabase in Nagarze, Southern Tibet

Widely distributed in Gyangzê-Chigu area, southern Tibet, NW- and nearly E-W-trending diabase（gabbro）-gabbro diorite dykes are regarded as the product of the large-scale spreading of the late Neo-Tethys Ocean. In order to constrain the emplacement age of these dykes, zircons of two samples from diabases in Nagarzê were dated by using the U-Pb SHRIMP method. Two nearly the same weighted mean ^206pb/^23SU ages were obtained in this paper, which are 134.9±1.8 Ma （MSWD=0.65） and 135.5 ± 2.1 Ma （MSWD=1.40）, respectively. They not only represent the crystallization age of the diabase, but also documented an important spreading event of the Neo-Tethys Ocean during the late Jurassic and early Cretaceous. This dating result is of great significance to reconstruct the temporal framework of the late Neo-Tethys Ocean in the Qinghai-Tibet Plateau.

Lymphatic spreading and lymphadenectomy for esophageal carcinoma

Esophageal carcinoma(EC) is a highly lethal malignancywith a poor prognosis. One of the most important prognostic factors in EC is lymph node status. Therefore, lymphadenectomy has been recognized as a key that influences the outcome of surgical treatment for EC. However, the lymphatic drainage system of the esophagus, including an abundant lymph-capillary network in the lamina propria and muscularis mucosa, is very complex with cervical, mediastinal and celiac node spreading. The extent of lymphadenectomy for EC has always been controversial because of the very complex pattern of lymph node spreading. In this article, published literature regarding lymphatic spreading was reviewed and the current lymphadenectomy trends for EC are discussed.

Low complexity method for spreading sequence estimation of DSSS signal in non-cooperative communication systems

It is a necessary step to estimate the spreading sequence of direct sequence spread spectrum （DSSS） signal for blind despreading and demodulation in non-cooperative communications. Two innovative and effective detection statistics are proposed to implement the synchronization and spreading sequence estimation procedure. The proposed algorithm also has a low computational complexity with only linear additions and modifications. Theoretical analysis and simulation results show that the algorithm performs quite well in low SNR environment, and is much better than all the existing typical algorithms with a comprehensive consideration both in performance and computational complexity.

Response of a pile group behind quay wall to liquefaction-induced lateral spreading:a shake-table investigation

The response of pile foundations near a quay wall under liquefaction-induced lateral spreading remains a complex problem. This study presents the results of a shake-table test on a 2×2 pile group behind a sheet-pile quay wall that was subjected to lateral spreading. The quay wall was employed to trigger liquefaction-induced large lateral ground deformation. The discussions focus on the behavior of the pile and the soil and on the bending moment distributions within the group pile and the restoring force characteristics at the superstructure. Overall, the piles exhibited apparent pinning effects that reduced soil deformation. In addition, the rear-row piles near the quay wall experienced larger bending moments than did the front-row piles, indicating significant pile group effects. The tests showed that lateral spreading could be a primary cause of larger monotonic deformations and bending moments. It can also be concluded that the monotonic bending moments were significantly decreased due to the presence of slow soil flow. The stiffness at the superstructure was reduced because of accumulated excess pore pressure before liquefaction, and it was recovered during lateral spreading. The present study further enhances current understanding of the behavior of low-cap pile foundations under lateral spreading.

Effects of structural characterizations on fragility functions of bridges subject to seismic shaking and lateral spreading

This paper evaluates the seismic vulnerability of different classes of typical bridges in California when subjected to seismic shaking or liquefaction-induced lateral spreading. The detailed structural configurations in terms of superstructure type, connection, continuity at support and foundation type, etc. render different damage resistant capability. Six classes of bridges are established based on their anticipated failure mechanisms under earthquake shaking. The numerical models that are capable of simulating the complex soil-structure interaction effects, nonlinear behavior of columns and connections are developed for each bridge class. The dynamic responses are obtained using nonlinear time history analyses for a suite of 250 earthquake motions with increasing intensity. An equivalent static analysis procedure is also implemented to evaluate the vulnerability of the bridges when subjected to liquefaction-induced lateral spreading. Fragility functions for each bridge class are derived and compared for both seismic shaking （based on nonlinear dynamic analyses） and lateral spreading （based on equivalent static analyses） for different performance states. The study finds that the fragility functions due to either ground shaking or lateral spreading show significant correlation with the structural characterizations, but differences emerge for ground shaking and lateral spreading conditions. Structural properties that will mostly affect the bridges＇ damage resistant capacity are also identified.

Simulating the Spreading of Two Competing Public Opinion Information on Complex Network

In this paper, we investigate the regularity of spreading of information and public opinions towards two competing products in complex networks. By building its mathematical model and simulating its evolution process, we have found the statistical regularity for support rates of two different products at a steady stage. The research shows that strength of the public opinion spreading is proportional to the final support rates of a product.

Empirical models for predicting lateral spreading considering the effect of regional seismicity

A revised empirical model has been developed for predicting liquefaction-induced lateral spreading displacement （LD） as a function of both response spectral acceleration derived from strong-motion attenuation models and geotechnical parameters from Youd＇s LD data set （Youd website）. This revised model is different from the model of Zhang and Zhao, which overcame some drawbacks of earlier models for predicting lateral spreading and was primarily used in Japan and the western U.S. The revised model can potentially be applied anywhere if ground shaking （in terms of 5% damped acceleration or displacement response spectra） can be estimated using local strong-motion attenuation relationships. The revised model is examined using data from Japan and the western U.S. and applied to Turkey and New Zealand, where the ground shaking is estimated using appropriate strong-motion attenuation relationships for each region. The accuracy of the revised model is evaluated by comparing its predicted lateral displacements with those measured in actual earthquakes. The results show that the revised model can account for the effects of local seismicity on lateral spreading displacements and is comparable with existing prediction models.

Numerical analyses of pile performance in laterally spreading frozen ground crust overlying liquefiable soils

Lateral spread of frozen ground crust over liquefied soil has caused extensive bridge foundation damage in the past winter earthquakes.A shake table experiment was conducted to investigate the performance of a model pile in this scenario and revealed unique pile failure mechanisms.The modelling results provided valuable data for validating numerical models.This paper presents analyses and results of this experiment using two numerical modeling approaches： solid-fluid coupled finite element（FE） modeling and the beam-on-nonlinear-Winkler-foundation（BNWF） method.A FE model was constructed based on the experiment configuration and subjected to earthquake loading.Soil and pile response results were presented and compared with experimental results to validate this model.The BNWF method was used to predict the pile response and failure mechanism.A p-y curve was presented for modelling the frozen ground crust with the free-field displacement from the experiment as loading.Pile responses were presented and compared with those of the experiment and FE model.It was concluded that the coupled FE model was effective in predicting formation of three plastic hinges at ground surface,ground crust-liquefiable soil interface and within the medium dense sand layer,while the BNWF method was only able to predict the latter two.

Rifting characteristics of eastern subbasin of South China Sea and its spreading pattern

With processing and interpretation of 25 000 km full-coverage multibeam swath data fromthe eastern South China Sea, it is found that NE-trending and NW-trending linear morphological features such as scarps, horsts and grabens, govern the central part (14°-17° N) of eastern subbasin. Compared with reflection seismic profiles, these NE-trending linear morpho-structures are considered to be the representation of basement structures on seabed and can be divided into three linear structural zones. The trend of the central zone is NE45°-50° occurring around extinct spreading center, the trend of the second zone is NE70° - 78° on both sides of the central one and the trend of the third zone is about NE60° just on the north of the second one. These three NE-trending linear zones are formed in late-stage NW - SE-trending seafloor spreading of the eastern subbasin along NW-trending linear faults, and respectively correspond to three spreading episodes: 17.0- 19.0 Ma (5d-5e), 19.0 - 21.0 Ma (5e-6a) and 21.0 - 24.2 Ma (6a-6c) based on the contrast of morpho-structures to magnetic lineation anomalies.

Cenozoic Volcanism in South China Sea and Its Vicinity and South China Sea Spreading

The rock series, rock types and Sr-Nd isotopic dating of the Cenozoicvolcanic rocks in the South China Sea are similar to those in its vicinity. On the basis of thespreading age of the South China Sea, the Cenozoic volcanic rocks are divided into three stages: thepre-spreading stage, the spreading stage and the post-spreading stage. The deep processcharacteristics of the asthenosphere and lithosphere may be inferred from the study on primarybasaltic magma. The top layers of the asthenosphere both in the spreading stage and in thepre-spreading stage are closer to the earth surface than that in the post-spreading stage. From thepre-spreading stage to the spreading stage, the top layer of the asthenosphere decreased in depth,while the amount of interstitial partial melts increased. The evolution of the primary basalticmagma shows a progressive evolution sequence of the rifting volcanism and a faster lithosphericspreading velocity. From the spreading stage to the post-spreading stage, the top layer of theasthenosphere gradually increased in depth, but the amount of interstitial partial melts decreased.The evolution of primary basaltic magma shows a retrogressive evolution sequence of the riftingvolcanism and a gradual decrease in the lithospheric spreading velocity. The depth recognized by thestudy on the Cenozoic volcanism demonstrates the deep environment for the formation and evolutionof the South China Sea.

Dynamic properties of epidemic spreading on finite size complex networks

The Internet presents a complex topological structure, on which computer viruses can easily spread. By using theoretical analysis and computer simulation methods, the dynamic process of disease spreading on finite size networks with complex topological structure is investigated. On the finite size networks, the spreading process of SIS （susceptibleinfected-susceptible） model is a finite Markov chain with an absorbing state. Two parameters, the survival probability and the conditional infecting probability, are introduced to describe the dynamic properties of disease spreading on finite size networks. Our results can help understanding computer virus epidemics and other spreading phenomena on communication and social networks. Also, knowledge about the dynamic character of virus spreading is helpful for adopting immunity policy.

Virus spreading in wireless sensor networks with a medium access control mechanism

In this paper, an extended version of standard susceptible-infected （SI） model is proposed to consider the influence of a medium access control mechanism on virus spreading in wireless sensor networks. Theoretical analysis shows that the medium access control mechanism obviously reduces the density of infected nodes in the networks, which has been ignored in previous studies. It is also found that by increasing the network node density or node communication radius greatly increases the number of infected nodes. The theoretical results are confirmed by numerical simulations.

Numerical study of three-dimensional wave-induced longshore current's effects on sediment spreading of the Huanghe River mouth

A three-dimensional wave radiation stress is introduced into the hydrodynamic sediment coupled model COHERENS-SED, which has been developed through introducing wave-enhanced bottom shear stress, wave dependent surface drag coefficient, wave-induced surface mixing, SWAN, damping function of sediment on turbulence, sediment model and depth-dependent wave radiation stress to COHERENS. The COHERENS-SED is adopted to study the effects induced by wave-induced three-dimensional longshore current on suspended sediment spreading of the Huanghe River （Yellow River） mouth. Several different cases divided by setting different wave parameters of inputting boundary waves are carried out. The modeling results agree with measurement data. In terms of simulation results, it is easy to know that three-dimensional wave radiation stress plays an obvious role when inputting boundary wave height is stronger than 3 m. Moreover, wave direction also affects the sediment spreading rules of the mouth strongly too.

A random walk evolution model of wireless sensor networks and virus spreading

In this paper, considering both cluster heads and sensor nodes, we propose a novel evolving a network model based on a random walk to study the fault tolerance decrease of wireless sensor networks （WSNs） due to node failure, and discuss the spreading dynamic behavior of viruses in the evolution model. A theoretical analysis shows that the WSN generated by such an evolution model not only has a strong fault tolerance, but also can dynamically balance the energy loss of the entire network. It is also found that although the increase of the density of cluster heads in the network reduces the network efficiency, it can effectively inhibit the spread of viruses. In addition, the heterogeneity of the network improves the network efficiency and enhances the virus prevalence. We confirm all the theoretical results with sufficient numerical simulations.

Seismic phases from the Moho and its implication on the ultraslow spreading ridge

The Moho interface provides critical evidence for crustal thickness and the mode of oceanic crust accretion. The seismic Moho interface has not been identified yet at the magma-rich segments （46°-52°E） of the ultra- slow spreading Southwestern Indian Ridge （SWIR）. This paper firstly deduces the characteristics and do- mains of seismic phases based on a theoretical oceanic crust model. Then, topographic correction is carried out for the OBS record sections along Profile Y3Y4 using the latest OBS data acquired from the detailed 3D seismic survey at the SWIR in 2010. Seismic phases are identified and analyzed, especially for the reflected and refracted seismic phases from the Moho. A 2D crustal model is finally established using the ray tracing and travel-time simulation method. The presence of reflected seismic phases at Segment 28 shows that the crustal rocks have been separated from the mantle by cooling and the Moho interface has already formed at zero age. The 2D seismic velocity structure across the axis of Segment 28 indicates that detachment faults play a key role during the processes of asymmetric oceanic crust accretion.

A modified stiffness spreading method for layout optimization of truss structures

The stiffness spreading method (SSM) was initially proposed for layout optimization of truss structures,in which an artificial elastic material of low modulus is uniformly distributed in the design domain to create connections between discrete members.In this paper,a modified stiffness spreading method is proposed by replacing the artificial elastic material with auxiliary bars to connect real members of the truss structure.Since the background continuum mesh for the elastic material is no longer required,the computational cost is significantly reduced.Like SSM,the new method is advantageous in that an initial design may consist of disconnected bars allocated in the design domain,and mathematical programming methods can be applied for the efficient solution of the formulated optimization problem.A number of solution strategies are also developed to achieve more practical designs with lower computational cost.Numerical examples of both 2-D and 3-D truss structures are presented to demonstrate the feasibility,robustness and effectiveness of the proposed method.