A computational method for wide-azimuth 3D dip-angle gathers using Gaussian beam migration

The dip-angle-domain common-image gather(DDCIG)is a key tool to separate the diffraction and reflection imaging results.Reflectors with different spatial geometries produce different responses in DDCIGs.Compared with Kirchhoff migration,Gaussian beam migration(GBM)is more effective and robust to overcome the multipathing problem.As a ray-based method,it has explicit angle information naturally during the propagation.We have developed a 3D DDCIG computational method using GBM,which obtain both the imaging result and angle-domain gathers with only one pass of calculation.The angle-gather computation is based on geometrical optics,and multiple angle conversions are implemented under the rules of space geometry,which helps to avoid rounding errors and improve accuracy.Additionally,the multi-azimuth joint presentation strategy is proposed to describe the characteristic of omnidirectional dip angles using a finite number of gathers.After using a 2D model to illustrate application advantages of DDCIG,we apply the proposed method to two 3D models to test its feasibility and accuracy.A field data example further demonstrates the adaptability of our method to seismic imaging for a land survey.

Experimental and numerical simulation study on the erosion behavior of the elbow of gathering pipeline in shale gas field

During the production period of shale gas, proppant particles and rock debris are produced together,which will seriously erode the elbows of gathering pipelines. In response to this problem, this paper takes the elbow of the gathering pipeline in the Changning Shale Gas Field as an example to test the erosion rate and material removal mechanism of the test piece at different angles of the elbow through experiments and compares the four erosion models with the experimental results. Through analysis, it is found that the best prediction model for quartz sand-carbon steel erosion is the Oka model. Based on the Oka model, FLUENT software was used to simulate and analyze the law of erosion of the elbow of the gas gathering pipeline under different gas flow velocities, gas gathering pressure, particle size, length of L1,and bending directions of the elbow. And a spiral pipeline structure is proposed to reduce the erosion rate of the elbow under the same working conditions. The results show that this structure can reduce erosion by 34%.

Fast least-squares prestack time migration via accelerating the explicit calculation of Hessian matrix with dip-angle Fresnel zone

Amplitude versus offset analysis is a fundamental tool for determining the physical properties of reservoirs but generally hampered by the blurred common image gathers(CIGs).The blurring can be optimally corrected using the blockwise least-squares prestack time migration(BLS-PSTM),where common-offset migrated sections are divided into a series of blocks related to the explicit offsetdependent Hessian matrix and the following inverse filtering is iteratively applied to invert the corresponding reflectivity.However,calculating the Hessian matrix is slow.We present a fast BLS-PSTM via accelerating Hessian calculation with dip-angle Fresnel zone(DFZ).DFZ is closely related to optimal migration aperture,which significantly attenuates migration swings and reduces the computational cost of PSTM.Specifically,our fast BLS-PSTM is implemented as a two-stage process.First,we limit the aperture for any imaging point with an approximated the projected Fresnel zone before calculating the Hessian matrix.Then,we determine whether a seismic trace contributes to the imaging point via DFZ during calculating the Hessian matrix.Numerical tests on synthetic and field data validate the distinct speedup with higher-quality CIGs compared to BLS-PSTM.

Research on a TOPSIS energy efficiency evaluation system for crude oil gathering and transportation systems based on a GA-BP neural network

As the main link of ground engineering,crude oil gathering and transportation systems require huge energy consumption and complex structures.It is necessary to establish an energy efficiency evaluation system for crude oil gathering and transportation systems and identify the energy efficiency gaps.In this paper,the energy efficiency evaluation system of the crude oil gathering and transportation system in an oilfield in western China is established.Combined with the big data analysis method,the GA-BP neural network is used to establish the energy efficiency index prediction model for crude oil gathering and transportation systems.The comprehensive energy consumption,gas consumption,power consumption,energy utilization rate,heat utilization rate,and power utilization rate of crude oil gathering and transportation systems are predicted.Considering the efficiency and unit consumption index of the crude oil gathering and transportation system,the energy efficiency evaluation system of the crude oil gathering and transportation system is established based on a game theory combined weighting method and TOPSIS evaluation method,and the subjective weight is determined by the triangular fuzzy analytic hierarchy process.The entropy weight method determines the objective weight,and the combined weight of game theory combines subjectivity with objectivity to comprehensively evaluate the comprehensive energy efficiency of crude oil gathering and transportation systems and their subsystems.Finally,the weak links in energy utilization are identified,and energy conservation and consumption reduction are improved.The above research provides technical support for the green,efficient and intelligent development of crude oil gathering and transportation systems.

基于多模态双协同Gather Transformer网络的虚假信息检测方法

社交媒体网站是人们在日常生活中分享信息、表达和交换意见的便捷平台。随着用户数量的不断增加,社交媒体网站上出现了大量的信息数据。然而,由于用户没有检查共享信息的可靠性,这些信息的真实性难以保证,从而导致大量虚假信息在社交媒体上广泛传播。然而,现有方法大多存在以下局限性:1)大多数方法通过简单提取文本与视觉特征,将其拼接后得到多模态特征来进行虚假信息判断,忽略了模态间和模态内细粒度内在联系,缺乏对关键信息的检索和筛选;2)多模态信息间缺乏指导性的特征提取,文本和视觉等特征之间缺乏交互增强,对多模态信息的理解不足。为了应对这些挑战,提出了一种新颖的基于多模态双协同Gather Transformer网络(Multimodal Dual-Collaborative Gather Transformer Network,MDCGTN)的虚假信息检测方法。在MDCGTN模型中,通过文本-视觉编码网络对文本和视觉信息的特征表示进行提取,将获得的视觉和文本特征表示输入多模态Gather Transformer网络进行多模态信息融合,使用Gather机制提取关键信息,充分捕捉和融合模态内和模态间细粒度关系。此外,设计了一个双协同机制对社交媒体帖子的多模态信息进行整合,以实现模态之间信息的交互和增强。在两个公开可用的基准数据集上进行了大量实验,结果表明,与现有的先进基准方法相比,所提方法准确率明显提升,证明了其对于虚假信息检测的优越性能。

Analysis of sensitivity to hydrate blockage risk in natural gas gathering pipeline

During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines,resulting in production reduction,shutdowns,and pressure build-ups.Consequently,a cascade of risks is prone to occur.To address this issue,this study focuses on the operational process of natural gas gathering and transmission pipelines,where a comprehensive framework is established.This framework includes theoretical models for pipeline temperature distribution,pipeline pressure distribution,multiphase flow within the pipeline,hydrate blockage,and numerical solution methods.By analyzing the influence of inlet temperature,inlet pressure,and terminal pressure on hydrate formation within the pipeline,the sensitivity patterns of hydrate blockage risks are derived.The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate,potentially mitigating pipeline blockage during natural gas transportation.Furthermore,an increase in inlet temperature and terminal pressure,and a decrease in inlet pressure,results in a displacement of the most probable location for hydrate blockage towards the terminal station.However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system,contradicting the operational goal of energy efficiency and reduction of energy consumption.Consequently,for high-pressure gathering pipelines,measures such as raising the inlet temperature or employing inhibitors,electrical heat tracing,and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation.Moreover,considering abnormal conditions such as gas well production and pipeline network shutdowns,which could potentially trigger hydrate formation,the installation of methanol injection connectors remains necessary to ensure production safety.

Global exhibitors from across textile spectrum gather at upcoming Intertextile Apparel

Shanghai,2 August 2024.Including everything from organic buttons and floral prints,to temperature-regulating and weather-resistant fibres,the apparel value chain is as diverse as it is extensive.Buyers at trade fairs with thousands of exhibitors can be hard pressed finding the fabrics they need,which is a key reason numerous suppliers at autumn's lntertextile Apparel will gather under the banners of specialised zones and pavilions.Taking place from 27-29 August at the National Exhibition and Convention Center (Shanghai),the fair will featu re eight product zones,including Accessories Vision,Functional Lab,and Verve for Design.Meanwhile,suppliers in eight country and region pavilions will showcase various innovations and high-quality textiles.Altogether the platform is set to welcome around 4,000 exhibitors from 25countries and regions.

智慧城市试点政策对城市碳排放强度的影响及机制分析

本文根据2000—2022年从中国218个城市收集的数据,使用多期模型实证分析了智慧城市试点政策对碳强度的影响,并从理论和实证角度分析了智慧城镇建设对城市碳强度的作用和机制,为未来构建更加完善的智慧城市提供经验指导。实证结果证实了试点政策可以有效降低城市地区的二氧化碳排放强度。同时,鼓励产业结构转型和现代化、促进人才库形式的高素质人才流动、采取适当的环境监管措施是试点城市降低碳减排强度的三种有效方法。此外,试点城市的碳减排强度因地理位置、数字基础设施水平和城市规模不同而有所差异。

基于实验和模拟分析的集输管道节能降耗输送研究

为解决高含水地面集输系统管输能耗高、运行成本大的问题,将室内实验与模拟分析相结合,通过带压模拟罐在室内完成典型区块含水原油粘壁速率和粘壁质量的测定,并通过现场降温实验验证粘壁温度准确性,随后针对集输管道的运行工况进行稳态数值模拟,分析出站温度变化对沿程温度、压力的影响,在确定管道不超压的条件下,完成常温输送的方案制定和实施。结果表明,粘壁质量发生突变对应的粘壁温度为28℃,该温度与原油析蜡高峰温度吻合;模拟结果显示,关停加热炉后,干线压力上升至1.26 MPa,但未超过最大允许外输压力;实施常温输送后,动力费用小幅增加,热力费用降为0元/h,总运行费用从320.63元/h降低至98.82元/h,预计全年可节约运行费用159.7万元。

Kirchhoff PSDM angle-gather generation based on the traveltime gradient

Angle-domain common-image gathers（ADCIGs） are the basic data in migration velocity analysis（MVA） and amplitude variation with angle（AVA） analysis. We propose a common-angle gather-generating scheme using Kirchhoff PSDM based on the traveltime gradient field. The scheme includes three major operations：（1） to calculate the traveltime field of the source and the receiver based on the dynamic programming approach;（2） to obtain the refl ection angle according to the traveltime gradient field in the image space; and（3） to generate the ADCIGs during the migration process. Because of the computation approach, the method for generating ADCIGs is superior to conventional ray-based methods. We use the proposed ADCIGs generation method in 3D large-scale seismic data. The key points of the method are the following.（1） We use common-shot datasets for migration,（2） we load traveltimes based on the shot aperture, and（3） we use the MPI and Open Mp memory sharing to decrease the amount of input and output（I/O）. Numerical examples using synthetic data suggest that the ADCIGs improve the quality of the velocity and the effectiveness of the 3D angle-gather generation scheme.

公立医院人才集聚现状及发展策略分析

人才集聚是多种因素导致的人才流动并集聚的过程。人才集聚可推动公立医院高质量发展、增强医院国际竞争力、促进医疗资源集聚、形成良好的群体促进效应。同时,人才集聚也会导致管理效率下降、大医院对人才和患者的虹吸作用增加、现有的制度阻碍集聚效应发挥等问题。因此,要强化管理职能,提高效率;抓住体制机制改革的机遇和突破口,破解“虹吸”难题;增强人事管理的适配性,推动人才集聚优势的发挥,建立生命健康领域人才高地。

GSVM:一种支持Gather/Scatter的向量存储器

宽单指令多数据流(Single Instruction Multiple Data,SIMD)架构数字信号处理器一般都能高效支持地址连续或等距跨步等规则应用的向量访存,但对于科学与工程计算中广泛存在的不规则应用的数据访存则带宽利用率往往较低,从而大幅降低了其整体运算能效。为了提高不规则应用的向量访存性能,基于某SIMD数字信号处理器的体系结构,设计了一种支持Gather/Scatter访存的向量存储器GSVM。通过设计与SIMD宽度相匹配的向量地址计算单元和合适深度的冲突缓冲器阵列,实现了Gather/Scatter指令向量地址计算、仲裁与缓存的全流水访存操作。实验结果表明,相比以前不支持Gather/Scatter访存的存储器,GSVM在增加22%的硬件代价基础上,基于稀疏矩阵向量乘的测试程序集获得了2~8的性能加速比。

基于AIS的海洋捕鱼聚集区信息系统设计与开发

本文设计并开发了一个基于AIS大数据的海洋捕鱼聚集区信息系统,提供了基于B/S架构的系统界面、服务功能和数据库的设计方案。主要功能包括:利用LSTM+HDBSCAN深度学习算法识别和管理捕鱼聚集区、网络地图浏览、测距、打印输出及用户管理等服务。系统前端采用Vue实现动态交互界面,后端使用Django处理业务逻辑,深度学习模型使用Python代码实现,数据库采用PostgreSQL进行数据存储和管理。本系统整合了深度学习算法与地理信息系统技术,能够有效地了解渔业资源的分布、变化和利用情况,为海洋空间规划和渔业经济发展提供帮助。

中小口径集输管道内检测技术研究进展

管道内检测是利用管输介质驱动检测器在管道内运行,实时检测和记录管道变形、腐蚀等损伤情况,并准确定位的作业。管道内检测作为在役管道检测最有效的手段已经广泛应用于实际工程中,但是对于中小口径(DN80~DN200)集输管道现阶段却没有非常有效的内检测手段。本文通过对某油田中小口径集输管道现状进行调研,梳理了中小口径集输管道进行内检测的难点,阐述了国内外管道广泛应用的内检测技术的适用范围、优缺点、技术现状以及应用情况,提出了解决中小口径集输管道内检测的可行性方案。

集输系统能效评价指标体系建立与应用

由于油田生产系统节能核算方法不完善,集输系统节能评估缺少完善的标准体系依据及综合能效评价方法。针对此问题,结合集输系统的能效水平现状、实际工况特点,通过建立新型能效评价指标体系、集输系统能耗及能效评价数学模型,制定多指标综合加权的集输系统能耗及能效评价方法,从而实现对集输系统整体能耗管理水平进行综合评价,为挖掘节能潜力提供指导依据。经过现场实践,集输站场内掺水泵、加热炉最高节能率分别可达22.28%和43.72%,能效综合评价等级由中提高至良。

基于仿生机构学落地红枣聚拢装置的设计与试验

针对南疆地区目前落地红枣无法聚集、人工捡拾效率低、机械化程度不高等问题,在分析枣树种植模式及红枣物料特性的基础上,采用仿人手臂聚集红枣的方法设计了一种快速聚拢装置,并确定了各零部件的结构参数。利用三维建模软件SolidWorks与运动学仿真软件ADAMS,对聚拢装置进行了建模与运动学仿真,结果表明:红枣在聚集过程中,接触的速度都是从小到大再到小,没有急剧的突变现象,对红枣的损害程度较小,符合设计工作要求。以红枣聚集率为响应指标,以前进速度、曲柄转速、滚筒转速为影响因素,设计了正交组合试验,建立了各因素对聚集率指标二次多项式回归模型,并分析了各因素对聚集率的影响规律。通过多重响应方法中的主目标函数法对其参数进行了优化,获得了影响红枣聚集率的最佳参数,即前进速度为0.37 m/s、曲柄转速为58 r/min、滚筒转速为32 r/min,此时红枣聚集率为88.65%。研究结果可为后续落地红枣聚拢装置的改进和研发提供参考。

Environment and Human Behaviors——Taking “The Acorn Gatherer” as a Case Study

Human living environment interacts with human behaviors.Environment to some degree determines human behaviors which in return reshape and sustain the dynamic environment.Taking Richard Jefferies' The Acorn Gatherer as a case study,this paper makes an argument that the behaviors of the villagers in the story can be more adequately interpreted in view of the backward countryside environment,and the same is true with the author Richard Jefferies' non-interference in the omniscient third-person point of view in writing the story.It is Richard Jefferies' family environment that makes up his viewpoint of writing,reflecting his critical loving of the countryside,where lives boom and conventions are extremely followed.

Social Conventions and Human Tragedy—On Richard Jefferies's The Acorn Gatherer

The Acorn Gatherer by Richard Jefferies is an allegorical tragedy, in which a nameless boy, born out of wedlock, is viewed as a sort of icon of sin, and is ultimately driven to death by the rigid and unforgiving social conventions.

信息收集和分发机制的遥感图像目标检测算法

遥感图像中的目标具有尺度多样、多类别以及背景复杂等特点,使得用于自然图像的目标检测算法在遥感图像目标检测中存在较多的漏检误检和精确度较低等现象。针对这些问题,提出一种基于YOLOv7改进的信息收集和分发机制的遥感图像目标检测算法。首先,设计一个信息收集和分发模块,用一个统一的模块收集不同特征图的信息并进行融合,将融合后的信息分发给需要的特征图,从而可以避免传统特征融合网络中固有的信息丢失,增强模型的特征融合能力从而提升模型的精确度。其次,NWD损失函数替换CIoU损失函数,缓解基于IoU的损失函数对小目标位置偏差的敏感,减少目标的漏检和误检。为了提升模型的收敛速度,设计一个超参数,同时使用NWD损失函数和IoU损失函数。在公开数据集RSOD上进行的实验结果表明,在复杂多样的情况下,改进后算法的平均精度均值(mAP)达到96.5%,相较原YOLOv7算法提升了15.8百分点,证明了改进后算法的适用性和有效性。

一种优化深度域速度反演的方法

山前带地震资料信噪比低,剩余速度场拾取困难,深度域速度场难以迭代收敛到最优,是山前带地震资料无法实现偏移准确归位的主要原因。利用五维数据规则化中的数据插值技术对偏移前的原始共中心点道集进行数据重构,通过改变观测系统,改善其面元属性,提高地震资料信噪比,以满足叠前深度偏移速度场迭代的需求。同时为了保证偏移数据的保真性,数据插值得到的高信噪比共中心点道集仅作为深度域速度场迭代反演的输入道集,原始共中心点道集作为最终叠前深度偏移成像的输入道集,在此基础上,实现了深度域速度场迭代的快速准确收敛。实际资料应用表明,该方法可行性强,迭代更新求取的最终偏移速度场准确,偏移剖面反射归位合理,可为山前带叠前深度偏移速度建模提供借鉴。