黏滑断层隧道减错措施参数对减错效果的影响分析

为提高黏滑断层隧道的结构安全性和稳定性,对黏滑断层隧道设置不同缝宽减错缝、不同刚度减错层的减错效果进行研究。研究结果表明:断层黏滑错动对上盘隧道的影响远大于下盘;减错缝对上盘部分隧道结构的减错效果优于下盘,其中上盘减错效果最大为24.50%,下盘减错效果最大为9.26%;减错层对下盘部分隧道结构的减错效果略优于上盘,其中下盘减错效果最大为105.32%,上盘减错效果最大为78.07%;随着减错缝宽度的增加,隧道上盘减错效果变好,下盘缝宽10—15cm减错效果最好;随着减错层弹性模量的增加,隧道上下盘减错效果降低,当减错层弹性模量增加到一定程度（约100MPa）,减错效果趋于稳定。研究成果可为黏滑断层隧道的减错结构设计及施工提供参考。     

An efficiency-improved genetic algorithm and its application on multimodal functions and a 2D common reflection surface stacking problem

Although Genetic Algorithms have found many successful applications in the field of exploration geophysics, the convergence speed remains a big challenge as Genetic Algorithms usually require a huge amount of fitness function evaluations. In this paper, we propose an efficiency-improved Genetic Algorithm, which has both a good global search capability and a good local search capability, and is also capable of robustly handling the premature convergence challenge commonly seen in linear and directed non-linear optimization methods. In our new genetic algorithm, the global search capability is performed via a modified island model, while the local search capability is provided by a novel self-adaptive differential evolution fine tuning scheme. Premature convergence is dealt with via a local exhaustive search method. We first demonstrate the much improved convergence speed of this efficiency-improved Genetic Algorithm over that of our previously proposed advanced Genetic Algorithm on several multimodal functions. We further demonstrate the effectiveness of our efficiency-improved Genetic Algorithm by applying it to a two-dimensional common reflection surface stacking problem, which is a highly nonlinear geophysical optimization problem, to obtain very encouraging results.     

可控震源参数选择及在煤田勘探中的应用

介绍了如何选择可控震源的扫描长度和震源台数、振动次数以及扫描频宽等参数 ,指出采用数台可控震源组合 ,增加扫描的总时间和利用相关技术是提高可控震源地震资料信噪比的有效方法 ,也是可控震源取得成功的关键。     

Optimized support vector regression algorithm-based modeling of ship dynamics

This study contributes to solving the problem of how to derive a simplistic model feasible for describing dynamics of different types of ships for maneuvering simulation employed to study maritime traffic and furthermore to provide ship models for simulation-based engineering test-beds. The problem is first addressed with the modification and simplification of a complicated and nonlinearly coupling vectorial representation in 6 degrees of freedom (DOF) to a 3 DOF model in a simple form for simultaneously capturing surge motions and steering motions based on several pieces of reasonable assumptions. The created simple dynamic model is aiming to be useful for different types of ships only with minor modifications on the experiment setup. Another issue concerning the proposed problem is the estimation of parameters in the model through a suitable technique, which is investigated by using the system identification in combination with full-scale ship trail tests, e.g., standard zigzag maneuvers. To improve the global optimization ability of support vector regression algorithm (SVR) based identification method, the artificial bee colony algorithm (ABC) presenting superior optimization performance with the advantage of few control parameters is used to optimize and assign the particular settings for structural parameters of SVR. Afterward, the simulation study on identifying a simplified dynamic model for a large container ship verifies the effectiveness of the optimized identification method at the same time inspires special considerations on further simplification of the initially simplified dynamic model. Finally, the further simplified dynamic model is validated through not only the simulation study on a container ship but also the experimental study on an unmanned surface vessel so-called I-Nav-II vessel. Either simulation study results or experimental study results demonstrate a valid model in a simple form for describing the dynamics of different types’ ships and also validate the performance of the proposed parameter estimation method.     

实时动态GPS测量转换参数求解分析

随着GPS测量技术的不断进步,目前动态GPS技术,特别是实时动态载波相位差分（RTK）技术,已成为GPS测量技术发展中的一个新的突破。但由于GPS测量采用WGS-84坐标系统,而我国目前所采用的坐标系统为1954北京坐标系（或1980国家大地坐标系、地方坐标系统等）,高程基准为1956年青岛黄海高程系（或1985国家高程基准）,所以GPS—RTK测量时必须先求解转换参数,以便于测量成果的应用。转换参数的求解是RTK测量的基础,转换参数的精确程度是影响RTK测量精度的关键因素。     

等级三星系统的运动学研究

统计分析表明,在目前的观测精度(Imas)下,由于三体效应大多数等级三星系统已不能用经典的双二体运动学模型来描述;即使对于应用需求而言,该模型也不再适用于描述三体视效应较强的等级三星系统.因为在实用星表参考架中不宜采用数据量较大的数值历表来描述子星的运动,所以有必要针对等级三星系统建立尽可能简单实用的运动学模型.借助已有的观测资料和拟合研究结果,给出了6个等级三星系统的质量参数和初始条件,进而根据实用需求讨论了这些系统的运动学描述问题.     

Site response analysis using one-dimensional equivalent-linear method and Bayesian filtering

Site response analysis is crucial to define the seismic hazard and distribution of damage during earthquakes. The equivalent-linear (EQL) is a numerical method widely investigated and used for site response analysis. Because several sources of uncertainty are involved in this type of analysis, parameters defining the numerical models need to be identified from in-situ measurements. In this paper, a Bayesian inference method to estimate the expected values and covariance matrix of the model parameters is presented. The methodology uses data from downhole arrays recorded during earthquakes. Two numerical applications show the good performance and prediction capabilities of the proposed approach.     

羊拉铜矿区岩石力学模拟与采场结构参数确定

采用三维弹塑性有限元程序3D-σ对羊拉铜矿的岩石力学进行模拟,并据此提出采场结构参数,对羊拉铜矿开采具有较好指导作用。     

Prediction and assimilation of surf-zone processes using a Bayesian network: Part II: Inverse models

A Bayesian network model has been developed to simulate a relatively simple problem of wave propagation in the surf zone (detailed in Part I). Here, we demonstrate that this Bayesian model can provide both inverse modeling and data-assimilation solutions for predicting offshore wave heights and depth estimates given limited wave-height and depth information from an onshore location. The inverse method is extended to allow data assimilation using observational inputs that are not compatible with deterministic solutions of the problem. These inputs include sand bar positions (instead of bathymetry) and estimates of the intensity of wave breaking (instead of wave-height observations). Our results indicate that wave breaking information is essential to reduce prediction errors. In many practical situations, this information could be provided from a shore-based observer or from remote-sensing systems. We show that various combinations of the assimilated inputs significantly reduce the uncertainty in the estimates of water depths and wave heights in the model domain. Application of the Bayesian network model to new field data demonstrated significant predictive skill (R² = 0.7) for the inverse estimate of a month-long time series of offshore wave heights. The Bayesian inverse results include uncertainty estimates that were shown to be most accurate when given uncertainty in the inputs (e.g., depth and tuning parameters). Furthermore, the inverse modeling was extended to directly estimate tuning parameters associated with the underlying wave-process model. The inverse estimates of the model parameters not only showed an offshore wave height dependence consistent with results of previous studies but the uncertainty estimates of the tuning parameters also explain previously reported variations in the model parameters.     

地震活动性参数的确定

本文基于目前国际上比较先进的地震危险性概率法，讨论了其中各地震活动性参数的具体确定方式及在实际工作中应该注意的问题。