Evolution of operational management procedures for the South African West Coast rock lobster (Jasus lalandii) fishery

The commercial fishery for Jasus lalandii, the South Africa West Coast rock lobster, began in the late 1800s and at its peak in the early 1950s yielded an annual catch of 18 000 t. Although this annual catch has dropped to only some 2000 t over recent years, the fishery remains South Africa's third most valuable for landed value. The primary reason for the low total allowable catch (TAC) over these recent years has been a marked drop in somatic growth rate that occurred at the end of the 1980s, for reasons that remain unexplained. A key problem in formulating TAC recommendations with longer‐term objectives in mind, has been uncertainties about likely future trends, particularly in somatic growth and recruitment. To address this problem, an “operational management procedure” (OMP) was adopted in 1997 and has twice been re‐evaluated and modified (in 2000 and 2003) in the light of further data and changing perceptions of resource dynamics. The history of this process is reviewed, concentrating on the most recent modification. In particular, a summary is given of the process by which the merits of alternative management procedures were evaluated over a range of important uncertainties about the dynamics of the resource. This summary includes a discussion of the key trade‐offs between resource rebuilding, future TAC trends and TAC variability, and the eventual choice that was made. The paper concludes by listing a number of lessons learnt concerning best practice for OMP development as this process evolved.     

Gyromat 2000陀螺经纬仪的应用

结合Gyrom at 2000陀螺经纬仪工作原理,对其测量过程和影响测量精度的主要因素进行分析讨论。并通过实验得出有益的结论。     

长清大学园区高架桥关键工序的施工方案

长清大学园区高架桥全长3.533 km,是济菏高速公路工程14个合同段中唯一一个全部是桥梁结构的标段。按照本工程的地理环境、地势条件、设计特点以及业主对工期和质量的要求,编制了一份以灌注桩和现浇连续箱梁为主要工序的施工方案。     

省级气象部门公文和Notes邮件在OA中的传输与实现

介绍了海南省气象局办公自动化系统的系统架构、运行环境及主要功能,并概述了系统所包含的公文系统、收文系统和文档管理系统,运用不同的公文模版实现了文、函等类型公文的拟稿、核稿、签发、审核、审批、盖章、文印、封发的流程管理、公文流转等多项功能,以及通过OA系统访问Notes邮件和个人E-mail邮件的功能,分析了实现相关功能所需的设计技术和实现方法,即运用工作流技术、职务岗位建模、权限控制、用户群组设计、公文痕迹保留等技术实现省级气象部门公文和Notes邮件在OA中的传输。     

地质数据三维可视化的属性、分类和关键技术

地质数据三维可视化具有显著的空间决策支持属性,其应用分类包括表达可视化、分析可视化、过程可视化、设计可视化和决策可视化。能否实现这两类"五个可视化",是检验所有地质三维可视化软件的水平和质量的试金石。地质数据三维可视化技术在矿产资源勘查、工程地质勘查、矿山设计开发、水利水电工程设计、地质灾害勘查治理和国防工程建设领域,有着广泛的需求和应用前景。其发展趋势是实现地上、地下、地理、地质数据一体化三维可视化采集、存储、管理、处理和集成应用。复杂地质结构的表达和快速动态建模方法和技术,仍将是未来一段时间的研究重点,引进知识驱动和本体论思路、方法,可能是解决这些问题的有效途径。     

福州地震台P2000测氡仪试测实验分析

对P2000与FD-125测氡仪进行为期一个半月的同步观测对比,并对P2000测氡仪该装置是否适用于地震氡观测及氡气标定器的刻度校正进行测试实验,根据观测的数据进行归纳和总结.结果表明,P2000测氡仪稳定性较好,操作使用简单,一次性充电可以连续使用十几个小时,较适用于野外观测.缺点是该测氡1次只能测1个水样,如果要测两平行样要六七个小时,时间相对较长.对观测的数据对比分析,发现虽然P2000测氡仪测值低于FD-125氡钍分析器的测值,但整体形态和趋势变化基本一致.     

复合加载模式下单桩复合筒型基础地基承载力包络线研究

海上风力发电机属于高耸结构物,其地基基础不仅要承受上部结构传递的竖向荷载V、水平荷载H,更要抵抗巨大的弯矩荷载M。单桩复合筒型基础是新型的海上风力发电机基础型式,建立复合加载模式下单桩复合筒型基础地基的破坏包络线,并据此评价其稳定性是地基基础设计的重要手段。在Swipe加载方法和固定位移比加载方法的基础上,通过数值分析研究了不排水饱和软黏土中单桩复合筒型基础在V-H、V-M、H-M和V-H-M加载模式下的地基承载力包络线,开展了室内模型试验,验证了数值分析结果的可靠性。研究表明,V-H和V-M加载模式下地基承载力包络线具有对称性,而H-M加载模式下呈非对称性;V-H-M加载模式下地基承载力包络线的形状受弯矩荷载M的影响显著,表现为随着弯矩荷载的增加,V-H平面内的破坏包络线逐渐缩小。实际工程中,可根据受力状态与破坏包络面的相对关系,评价单桩复合筒型基础的稳定性。     

不同土层地震反应计算程序对比分析

目前在中、美两国场地土层地震反应分析中,应用比较广泛的计算软件为ESE和SHAKE,两者均采用频域等效线性化方法处理非线性的土层动本构关系。本文采用上述软件分别对三种典型场地进行计算,分析两者差别及造成差别的原因。研究结果表明,SHAKE软件在深软场地时,计算反应谱和加速度峰值均与实际统计结果差别较大,不适合工程应用。ESE软件计算结果比较合理。     

城市战略规划研究

文章论述了研究城市战略规划的背景和目的,提出了城市战略规划的编制程序：可采用一种系统循环方法,包含潜力研究、目标选择和方略制定三大步骤;其研究框架由基础研究、专题研究、战略研究三部分组成。认为城市战略规划在一定程度上能弥补我国城市总体规划编制的欠缺;实施城市战略规划需要有理论基础、法律保障及公众参与来支撑。     

An efficient measure of compactness for two-dimensional shapes and its application in regionalization problems

A measure of shape compactness is a numerical quantity representing the degree to which a shape is compact. Ways to provide an accurate measure have been given great attention due to its application in a broad range of GIS problems, such as detecting clustering patterns from remote-sensing images, understanding urban sprawl, and redrawing electoral districts to avoid gerrymandering. In this article, we propose an effective and efficient approach to computing shape compactness based on the moment of inertia (MI), a well-known concept in physics. The mathematical framework and the computer implementation for both raster and vector models are discussed in detail. In addition to computing compactness for a single shape, we propose a computational method that is capable of calculating the variations in compactness as a shape grows or shrinks, which is a typical application found in regionalization problems. We conducted a number of experiments that demonstrate the superiority of the MI over the popular isoperimetric quotient approach in terms of (1) computational efficiency; (2) tolerance of positional uncertainty and irregular boundaries; (3) ability to handle shapes with holes and multiple parts; and (4) applicability and efficacy in districting/zonation/regionalization problems.