A combination line transect and capture-recapture sampling model for multiple observers in aerial surveys

We present a robust sampling methodology to estimate population size using line transect and capture-recapture procedures for aerial surveys. Aerial surveys usually underestimate population density due to animals being missed. A combination of capture-recapture and line transect sampling methods with multiple observers allows violation of the assumption that all animals on the centreline are sighted from the air. We illustrate our method with an example of inanimate objects which shows evidence of failure of the assumption that all objects on the centreline have probability 1 of being detected. A simulation study is implemented to evaluate the performance of three variations of the Lincoln-Petersen estimator: the overall estimator, the stratified estimator, and the general stratified estimator based on the combined likelihood proposed in this paper. The stratified Lincoln-Petersen estimator based on the combined likelihood is found to be generally superior to the other estimators.     

Estimating Population Size in a Continuous-time Removal Experiment with a Known Sub-population Size Ratio

We study a continuous-time removal model for estimating the population size for a population in which a sub-population size ratio is known. The maximum likelihood estimate and the optimal martingale estimate of the population size are obtained; these are shown to be equivalent. A comparison between the proposed estimator and the maximum likelihood estimate which ignores the information on the known size ratio is made, using a simulation study. The asymptotic variances of these two estimators are also obtained, and a comparison between them is made. The sensitivity of mis-specification of the known size ratio is examined. We also apply the corresponding discrete-time model to the proposed continuous-time setting, and study the efficiency of the corresponding discrete-time type estimator relative to the proposed estimator.     

冷挤压组合凹模的寿命估算

冷挤压组合凹模的失效主要是凹模内腔疲劳裂纹的出现,在模具设计的前期较为准确的估算出组合凹模的疲劳寿命是模具优化设计的前提。通过对组合凹模的应力分析后,采用Mises屈服准则的方法把凹模所受的多轴应力转化成单轴应力,再利用局部应力应变法找到了估算冷挤压组合凹模寿命的途径。     

建立我国主要农作物卫星遥感估产运行系统的主要技术环节及解决途径

本文结合我国耕地和作物种植特点,并根据“八五”攻关实践,指出了建立我国主要农作物（小麦、玉米、水稻、棉花、大豆）卫星遥感估产运行系统所面临的主要技术环节,即系统的工程化总体设计；卫星遥感估产区划；背景数据库的建立；遥感信息同化技术；不同作物面积提取、长势监测与单产模型；运行系统的建立。进一步提出了系统实现的技术方案、步骤和解决这些主要技术环节的设想,即统一组织实施,避免重复工作；抓住主要农作物主产区遥感估产,以河南、安徽、江苏３省为多种作物综合卫星遥感估产试点省；结合遥感信息同化技术,建立面积提取、长势监测、单产模型体系和相应的软件模块；最终建立全国的卫星遥感估产集成系统。     

湿地经济价值分析

黑龙江省三江平原来开发前分布着广阔、成片的平原沼泽湿地，由于近几十年开发建设，原始湿地面积大量减少．本文通过湿地经济价值分析，说明保护湿地的重要性。     

长春市水环境生态系统服务功能价值评估

生态系统服务不是无偿提供的，而是用货币量算，价值不菲。对长春市水生态系统的5项服务功能进行估算累加。可以得出目前长春市水生态系统服务每年价值在62599．35万元之上。比1990年的水生态系统服务价值有所削减。也就是说，在过去10a间，长春市水生环境给人们提供的福利在减少。因为各技术和学科本身的局限，所得值只能作为决策者的参考，而更精确的结果需要更合理的方法和更深入广泛的研究。     

污水处理厂内毒物归宿模型的参数估计及应用

在建立城市污水处理厂毒物归宿模型的基础上，继续探讨了固液相吸附分配系数Ｋｐ，生物降解速率系数Ｋｂ，挥发及吹脱速率系数ＫｖＫｓｔ等模型参数的估计方法，并就模型的检验，模拟及其在风险评价中的应用作了案例研究。     

农药降解方程y=ae~(-kt)参数估计的一种方法

农药降解方程ｙ＝ａｅ－ｋｔ参数估计的一种方法王增辉王蕴波窦森贾红震（吉林农业大学基础科学系，长春１３０１１８）关键词降解方程，参数估计．１前言在农药的降解规律研究中，一般都认为，农药在土壤中、植物上的消失，可用一级反应动力学公式来表示［１］，即在不考...     

LINEAR PROGRAMS FOR NONLINEAR HYDROLOGIC ESTIMATION1

ABSTRACT: The minimization of the sum of absolute deviations and the minimization of the absolute maximum deviation (mini-max) were transformed into equivalent linear programs for the estimation of parameters in a transient and linear hydrologic system. It is demonstrated that these two methods yield viable parameter estimates that are globally optimal and reproduce properly the timing and magnitude of hydrologic events and associated variables such as total runoff. The two linear estimation methods compared favorably with the popular least-squares nonlinear estimation method. The generality of the theoretical developments shows that linear program equivalents are adequate competitors of nonlinear methods of hydrologic estimation and parameter calibration.     

THE DEVELOPMENT OF THE NILE HYDROMETEOROLOGICAL FORECAST SYSTEM1

ABSTRACT: The National Oceanic and Atmospheric Administration is developing a river forecast system for the Nile River in Egypt. The river forecast system operates on scientific work stations using hydrometeorological models and software to predict inflows into the high Aswan Dam and forecast flow hydrographs at selected gaging locations above the dam The Nile Forecasting System (NFS) utilizes satellite imagery from the METEOSAT satellite as the input to the forecast system. Satellite imagery is used to estimate precipitation over the Blue Nile Basin using five different techniques. Observed precipitation data and climatic statistics are used to improve precipitation estimation. Precipitation data for grid locations are input to a distributed water balance model, a hill slope routing model, and a channel routing model. A customized Geographic Information System (GIS) was developed to show political boundaries, rivers, terrain elevation, and gaging network. The GIS was used to develop hydrologic parameters for the basin and is used for multiple display features.