Modeling long-period noise in kinematic GPS applications

We develop and test an algorithm for modeling and removing elevation error in kinematic GPS trajectories in the context of a kinematic GPS survey of the salar de Uyuni, Bolivia. Noise in the kinematic trajectory ranges over 15 cm and is highly autocorrelated, resulting in significant contamination of the topographic signal. We solve for a noise model using crossover differences at trajectory intersections as constraints in a least-squares inversion. Validation of the model using multiple realizations of synthetic/simulated noise shows an average decrease in root-mean-square-error (RMSE) by a factor of four. Applying the model to data from the salar de Uyuni survey, we find that crossover differences drop by a factor of eight (from an RMSE of 5.6 to 0.7 cm), and previously obscured topographic features are revealed in a plan view of the corrected trajectory. We believe that this algorithm can be successfully adapted to other survey methods that employ kinematic GPS for positioning.     

非洲"铜带"铜钴工业地域综合体初步研究

非洲“铜带”是世界上最大的铜钴工业综合体之一。通过实地调查和资料分析,揭示了“铜带”铜钴工业的地域组合特征及空间布局的内在联系规律;剖析了“铜带”铜钴工业地域综合体形成的主要地理条件,尤其是制约冶金工业生产布局的矿物资源、电力和交通运输条件;探讨了主导工业部门在工业地域综合形体形成和区域经济社会发展过程中“联动”和“极化”作用。这对我国在矿山开发过程澡,充分发挥矿业的主导作用带动区域经济社会发展,     

工业测量系统在多波束天线安装检测中的应用

根据多波束天线测量和检测的实际情况 ,主要介绍了多波束天线的数学模型、解算方法、测量方案的设计以及调整量的计算等问题。最后对实测结果进行了分析。     

石油测井光电编码器深度测量系统

介绍了石油测井深度光电编码器测量系统的测量原理、系统组成以及电路分析,同时在对系统误差分析的基础上给出了具体校正方法。     

工业城市可持续发展的矛盾与对策分析--以株洲市为例

以湖南省株洲市为实例，从经济与社会、环境的角度进行比较分析影响工业城市可持续发展的主要因素。指出工业城市与可持续发展的矛盾是资源消耗大、环境污染严重、经济开发区资源浪费大。并提出发展循环经济、建立生态工业、做好城市的整体规划等对策和建议。     

Application of linear and nonlinear techniques in river flow forecasting in the Kilombero River basin,Tanzania / Application de techniques linéaires et non-linéaires à la prévision des débits dans le bassin de la Rivière Kilombero,en Tanzanie

Abstract

Modelling of the rainfall–runoff transformation process and routing of river flows in the Kilombero River basin and its five sub-catchments within the Rufiji River basin in Tanzania was undertaken using three system (black-box) models—a simple linear model, a linear perturbation model and a linear varying gain factor model—in their linear transfer function forms. A lumped conceptual model—the soil moisture accounting and routing model—was also applied to the sub-catchments and the basin. The HEC-HMS model, which is a distributed model, was applied only to the entire Kilombero River basin. River discharge, rainfall and potential evaporation data were used as inputs to the appropriate models and it was observed that sometimes the system models performed better than complex hydrological models, especially in large catchments, illustrating the usefulness of using simple black-box models in datascarce situations.     

论英国资产阶级革命初期的地主政治

英国从封建社会向资本主义社会过渡时期 ,新兴地主阶级崛起 ,赖其拥有雄厚的经济实力 ,得以入选国会 ,在资产阶级革命时成为领导阶级 ,随后独掌政权。英国地主政治废除一些封建法规 ,大肆推行圈地运动 ,鼓励发展工商业 ,在维护地主阶级利益的同时 ,一定程度上满足了资产阶级的要求 ,不自觉地加快了资本原始积累的进程 ,导致英国率先爆发工业革命。工业革命改变了英国国内各阶级的经济实力和力量对比。工业资产阶级乘势而起 ,经过几次社会改革终于取代地主阶级而成为当权者。     

Evaluating infiltration losses in a Mediterranean wetland: Las Tablas de Daimiel National Park,Spain

Las Tablas de Daimiel National Park is a series of wetlands which naturally originated from groundwater discharges from the Mancha Occidental aquifer, Spain. Despite the relatively large size of this aquifer, 30 years of intensive groundwater pumping have significantly depleted the water table. As a result, wetlands only remain functional due to artificial inflows. Infiltration loss is therefore a key parameter to evaluate how much water is needed to maintain ecosystem functionality. Although yearly infiltration estimates existed prior to this work, these did not take into account key parameters such as the temporal evolution of the flooded area. This paper presents a more concrete estimate of the average infiltration losses. Infiltration is calculated as the closure term of daily water balances during a period of time where all other elements were known to an acceptable accuracy. A validation mechanism is provided to check the potential utility of the calculated infiltration in wetland management practices. Copyright © 2008 John Wiley & Sons, Ltd.     

人口移动与区域经济格局变动

人口移动是我国近几年发生的重要社会经济现象之一,其机制是东部地区人多地少的推力与西部地区产业结构性空缺的吸力,以及国家对后者特定的工资与粮食政策。它对地域分工格局的变动产生着重大影响。     

The status of artisanal fishing in El Salvador

El Salvador is one of the most environmentally degraded nations in Latin America, but the declining fishing industry is under-studied compared with deforestation and landuse. This paper examines the reactions to fish stock decline of two generations of fishers in La Union, El Salvador on the Golfo de Fonseca, one of the most important fishing areas in Latin America, using face to face interviews and questionaires. Both older (>35 years) and younger (<36 years) fishers supplemented their income with trading, farming and loans from their relatives in the United States. All older fishers reported larger fish catches five and ten years previously than at present. Previously, fishers caught more fish, but significantly more younger fishers than older fishers reported their fathers caught more fish than they did, indicating an increasing gap in fish catches in recent decades. More younger fishers than older fishers had fathers or male kin who were also fishers, indicating young men were less likely to join fishing without a parent or kin already involved. Minorities of both older and younger fishers engaged in supplementary activities. Environmental degradation disuaded fishers from switching to farming or hunting. The findings are similar to findings elsewhere on the decline of fish resources and generational gaps in environmental knowledge, but differ in that some other studies report fewer opportunities for fishers to access alternative or complementary activities. These findings are relevant to Latin American studies, considering the great value of the Golfo de Fonseca to the livelihoods of Central America.