Assessing and managing data‐limited ornamental fisheries in coral reefs

Coral reefs support numerous ornamental fisheries, but there are concerns about stock sustainability due to the volume of animals caught. Such impacts are difficult to quantify and manage because fishery data are often lacking. Here, we suggest a framework that integrates several data‐poor assessment and management methods in order to provide management guidance for fisheries that differ widely in the kinds and amounts of data available. First, a resource manager could assess the status of the ecosystem (using quantitative metrics where data are available and semi‐quantitative risk assessment where they are not) and determine whether overall fishing mortality should be reduced. Next, productivity susceptibility analysis can be used to estimate vulnerability to fishing using basic information on life history and the nature of the fishery. Information on the relative degree of exploitation (e.g. export data or ratios of fish density inside and outside no‐take marine reserves) is then combined with the vulnerability ranks to prioritize species for precautionary management and further analysis. For example, species that are both highly exploited and vulnerable are good candidates for precautionary reductions in allowable capture. Species that appear to be less vulnerable could be managed on a stock‐specific basis to prevent over‐exploitation of some species resulting from the use of aggregate catch limits. The framework could be applied to coral reef ornamental fisheries which typically lack landings, catch‐per‐unit‐effort and age‐size data to generate management guidance to reduce overfishing risk. We illustrate the application of this framework to an ornamental fishery in Indonesia.     

农业大数据信息采集平台建设研究

农业大数据已成为推动农业转型升级,提高生产决策的重要手段.本研究在充分分析农业大数据信息采集平台建设意义与目标的基础上,提出了农业大数据信息采集平台的建设思路以及整体框架,描述了平台采集的信息方式、采集内容方式,并设计了系统的核心功能,试图通过搭建农业大数据信息采集平台,推动农业相关信息资源体系建设,为农业大数据产业发...     

基于WSN的油菜生长环境数据采集系统

针对传统作物生长环境数据获取手段实时性差、劳动强度大以及部署微型自动气象站和商用Zigbee产品成本高、开放性较差等问题,设计并实现了一种基于WSN的油菜生长环境数据采集系统。提出了轻量级的能量感知路由协议CLFP,并给出了软硬件的相关设计方法。仿真和大田试验结果表明,系统温度采集精度最高可达0.01 ℃,测湿精度达±5%,光强采集范围为1~65 535 lx,可并发的数据传输达到36路,可满足农业现场环境数据的较高测量要求。在标称电源供电情况下,系统实际有效生存周期超过142 d,由于采用AT89C51和nRF2401作为基础硬件平台,成本低廉,有助于大规模部署和应用。     

中国产业结构优化升级引致的城镇化效应研究——一个省级面板分位数模型的实证检验

基于2000~2011年我国省级面板数据,采用面板分位数计量模型考察了产业结构引致的城镇化效应。研究发现,第三产业份额的估计参数显著为正,说明产业结构优化带来的城镇化效应是存在的。同时,这种效应对于处于不同分位数上的地区有较大差异：第三产业份额适中的省（市、自治区）,城镇化效应最为明显;第三产业份额相对过高或过低的省（市、自治区）,产业结构优化带来的城镇化效应较弱,估计参数呈现“两头小、中间大”的结果,显著、稳健为“倒U型”结构。     

交流伺服电机速度与位置环的一体化鲁棒控制

考虑损失流量三角形中同一事故年的损失随时间反复观测的纵向特征,将损失流量三角形视为分层数据,结合损失进展的增长曲线,提出了关于索赔准备金评估的两种非线性分层增长曲线模型,并应用R软件对精算实务中的实例给出了数值分析。提出的非线性分层模型为考虑多个事故年的损失进展建模提供了一种自然灵活的框架,使得建立的模型易于理解,同时在分层建模中纳入了增长曲线,也有效避免了尾部进展因子的选定问题。     

超声数据采集系统设计

本文涉及水下微地形超声探测仪的研发,主要探讨超声探测仪核心系统-超声数据采集系统的设计。首先确定该数据采集系统的基本结构,然后依据探测精度要求对数据采集卡进行选型,最后完成基于PCI-1714高速数据采集卡的超声数据采集软件系统设计,成功开发超声数据采集系统。     

基于OGSA网格技术的连锁超市进销存系统研究

本研究采用网格计算技术使进销存系统从简单的计算资源集中上升到数据共享层面,并且实现了协作处理和网络节点的高质量的服务,能极大的提高连锁超市间计算资源的效率和利用率,有效破解因计算能力差、数据来源单一或存储资源欠缺而无法解决的问题。     

Prediction of daily reference evapotranspiration by a multiple regression method based on weather forecast data

Prediction of daily reference evapotranspiration (ET ₀) is the basis of real-time irrigation scheduling. A multiple regression method for ET ₀ prediction based on its seasonal variation pattern and public weather forecast data was presented for application in East China. The forecasted maximum temperature (T _max), minimum temperature (T _min) and weather condition index (WCI) were adopted to calculate the correction coefficient by multilinear regression under five time-division regimes (10 days, monthly, seasonal, semi-annual and annual). The multiple regression method was tested for its feasibility for ET ₀ prediction using forecasted weather data as the input, and the monthly regime was selected as the most suitable. Average absolute error (AAE) and root mean square error (RMSE) were 0.395 and 0.522 mm d^?1, respectively. ET ₀ prediction errors increased linearly with the increase in temperature prediction error. A temperature error within 3 K is likely to result in acceptable ET ₀ predictions, with AAE and average absolute relative error (AARE) <0.142 mm d^?1 and 5.8%, respectively. However, one rank error in WCI results in a much larger error in ET ₀ prediction due to the high sensitivity of the correction coefficient to WCI and the large relative error in WCI caused by one rank deviation. Improving the accuracy of weather forecasts, especially for WCI prediction, is helpful in obtaining better estimations of ET ₀ based on public weather data.     

山地电力架空线路运维质量的智能评估

山地电力架空线路大多沿山架设,穿越树竹林,周边的树竹生长缺陷引发短路故障频繁发生,造成用电客户的大量投诉,用户体验满意度下降,抢修抢险费用大幅度攀升,严重影响供电公司的信誉和售电收益.为了提升用电客户的满意度和供电公司的售电受益,采用主成分分析方法提取了山地电力架空线路通道运维质量的3个主要影响因素,它们分别是树竹生长缺陷数、缺陷的消除数和通道运维资金使用合理度.对树竹的生长规律建立一个预测模型,从而得到树竹生长缺陷数的一个预测,根据预测结果划拨架空线路所在供电所的运维资金,消除树竹生长的缺陷数,再用Logistic回归模型,构建架空线路通道运维质量智能评估模型,使供电公司对架空线路运维实现基于数据决策的模式,尽可能保证供电线路零故障运行.     

食用菌栽培与旅游业融合力评价研究

改革开放以来,经济的发展和市场的巨大需求使食用菌成为我国农民增收的主要经济作物,食用菌产业是公认的朝阳产业。但是由于经济现状的限制,食用菌产业的发展常以市场为主导,急需采用先进的发展理念,使食用菌产业更加科学合理的发展。以因子分析法为基础进一步构建研究模型,采用回归分析法,对食用菌种植与旅游业融合力进行评价。回归分析结果显示,变量融合广度、融合深度、融合增值对食用菌种植与旅游业融合力有显著的正向影响。