Development and application of a coupled-process parameter inversion model based on the maximum likelihood estimation method

The coupled flow-mass transport inverse problem is formulated using the maximum likelihood estimation concept. An evolutionary computational algorithm, the genetic algorithm, is applied to search for a global or near-global solution. The resulting inverse model allows for flow and transport parameter estimation, based on inversion of spatial and temporal distributions of head and concentration measurements. Numerical experiments using a subset of the three-dimensional tracer tests conducted at the Columbus, Mississippi site are presented to test the model's ability to identify a wide range of parameters and parametrization schemes. The results indicate that the model can be applied to identify zoned parameters of hydraulic conductivity, geostatistical parameters of the hydraulic conductivity field, angle of hydraulic conductivity anisotropy, solute hydrodynamic dispersivity, and sorption parameters. The identification criterion, or objective function residual, is shown to decrease significantly as the complexity of the hydraulic conductivity parametrization is increased. Predictive modeling using the estimated parameters indicated that the geostatistical hydraulic conductivity distribution scheme produced good agreement between simulated and observed heads and concentrations. The genetic algorithm, while providing apparently robust solutions, is found to be considerably less efficient computationally than a quasi-Newton algorithm.     

吉林省“出海”通道及其开发战略研究

“出海”通道对于吉林省来说是经济对外开放和经济地域布局的重要因素。文章描述了“出海”通道的现状,对不同通道做了运输成本的比较分析,提出通道“闲置”的结论并阐述了其深层次原因,在此基础上讨论了通道与省区产业开发的战略。     

City vs Country: The demise of the brewing industry in country New South Wales,c .1898-1932

At the end of the 1880s, eight in ten breweries in the colony of New South Wales were located in country (non-metropolitan) areas, and these accounted for about 25 per cent of total colonial beer production. The number of country breweries experienced a dramatic decline after the 1880s, reaching only two by 1932. This process occurred in three more-or-less discrete stages: until about 1900, when internal restructuring reduced the number from about 65 to about 40; a decade or two after 1900 when, facilitated by the Sydney-centred railway network, city competition further reduced the number; and a period, mainly in the 1920s, typified by takeovers of country by city breweries. Additionally, the elimination of border duties after Federation introduced Melbourne competition to brewers in the southern part of the state.     

Occurrence of bed load transport in the presence of stable clast

It is well-versed that transport occurrence is vital for in stream rehabilitation, river restoration and installment of sediment sampler on river beds. Current practice emulates the use of continuous pre-diction using reach-averaged approach. However, prediction of transport occurrence entails the use of binary model through the execution of logistic regression analysis. Bed load and turbulence data were physically measured at mountainous region with divergent surface bedform in its presence. The para-meterization and statistical approaches are treated in the similar fashion with multiple regression except for the test for model fit and model selection criterion. The parameters on near-bed turbulence char-acteristics at the entrainment threshold were assigned as independent variables containing 15 pre-dictors. Almost 80 models were generated by selecting the best possible combination in accordance with the statistical precaution of alleviating multicollinearity issue. It is postulated that the model containing shields stress in the form of turbulent kinetic energy (TKE) at vertical direction and fractional time for second quadrant provides better estimation of potential location for greatest sediment-entrainment;hence a high possibility for transport occurrence.     

人文主义地理学蕴含的现象学——对大卫·西蒙《生活世界地理学》的评介

中国大陆地理学界对人文主义地理学与现象学之关系的介绍不甚充分,引介的文章数量十分有限,且多集中介绍段义孚先生的作品和观点。文章通过评介另一位著名人文主义地理学家大卫·西蒙的《生活世界地理学--动、静和相遇》,旨在促进人们更为深入地了解人文主义地理学。此书是人文主义地理学的代表著作之一,出版之际正值西方人文主义地理学盛行。全书共分为5大部分,其中第二、三、四部分集中了作者的学术观点,分别对应该书副标题中的“动”“静”和“相遇”。现象学是人文主义地理学的哲学基础,内容比较艰涩。因此文章结合该书提到的例子和经验中的例子,凝练出该书的重要观点,并使其形象化。文章评介该书的基本观点是：第一,该书通过抽象的现象学的概念和方法实现了对大量日常环境经验的描述;第二,该书内容对规划设计以及环境教育相关人士具有启发性和指导意义;第三,该书并没有实现人文主义地理学与“科学的”现代地理学的直观对比,因此尚未显性化现象学研究方法的优长;第四,以现象学态度反观本评介,本评介当然也带有两位作者的主体性。     

多样vs.分裂:论中国人文地理学发展的多元性及其挑战

从哲学、理论、方法和实践4个方面梳理了中国人文地理学内部的多元性,并区分了这些多元性的性质,即哪些是缺乏交流和整合的“散见”、哪些是需要统一和弥合的“歧见”、哪些是认识局限导致的“偏见”。据此建议加强中国人文地理学研究的问题意识和原创性理论研究;减少对“主义”的过度推崇和对方法的盲目崇拜;加强定性方法和定量方法的交流及论证过程的严谨性;在政策取向上取得“求真”和“务实”的平衡;提高学科发展的自信和对不同研究视角的包容。此外,应该在研究选题、杂志建设和奖项设置等操作层面推动人文地理学的理论整合。     

技术型新创企业的地理学研究进展

在辨析技术型新创企业的概念与分类基础上,从技术型新创企业的时空特征及其与区域环境的互动关系出发,梳理技术型新创企业的地理学研究成果。研究结果表明技术型新创企业在空间上更趋于集聚分布,其时空演变并非随机的,而是具有一定的连续累积性和路径依赖性;区域环境影响技术型新创企业的产生与发展,并形成了创业知识溢出理论、创业生态系统理论和区域创业系统理论三大代表性理论成果,而技术型新创企业可以提高区域生产和创新效率,开辟区域增长新路径,是区域创新系统实现动态发展、摆脱路径依赖和锁定的重要机制。同时创业企业家作为能动性主体,也能在一定程度上对区域软环境进行重塑和变革。最后在总结国内外研究进展的基础上,指出当前研究的不足与方向。     

地理信息技术在高中地理教学中的应用

地理信息技术在高中地理教育中的作用越来越重要,根据2017年《普通高中地理课程标准》提出的具体内容要求和学业要求,对地理信息技术在高中地理教育中的重要性作了具体的论证;教学中的具体应用案例表明,将遥感、全球定位系统、地理信息系统应用于普通高中地理教学,不仅可以极大的增强学生的学习兴趣,还可以培养学生的地形解读和空间思维能力;同时结合中国普通高中的实际情况,对地理信息技术在高中地理教学中面临的问题也进行了一定的探究,并给出了合理的建议。     

南海潜热交换年际与年代际变化的分析探讨

根据一套客观分析潜热通量、基于绕岛理论诊断的南海贯穿流(LST)、南海热含量等月平均资料,分析南海表层潜热通量的年际和年代际变化特征。南海地区的潜热通量冬季强,春季的潜热通量弱;在秋冬季节,南海北部的潜热通量远大于南部;夏季南海潜热通量南部高于北部;从20世纪80年代初潜热通量逐渐增加。使用EOF经验正交分解,M-K检验方法分析南海潜热通量的多时间尺度变化,前3个模态的方差贡献率分别为:53.01%(主要为长期趋势)、17.4%(年代际变化)、6.71%(年际变化)。分析表明在年际尺度上南海贯穿流(LST)减少导致南海海表温度(SST)增温幅度上升,海气温差比湿差减小,从而导致潜热释放减少,潜热通量呈负异常;反之LST进入南海增多,海气温差比湿差变大,导致南海潜热损失减少,潜热通量呈正异常。     

Estimation of the dispersion coefficient in rivers with riparian vegetation

The study of the transport processes in the riparian environment is currently a subject of great interest. In this context, the evaluation of longitudinal dispersion is a fundamental issue. Although it plays an important role in the transport of chemicals, nutrients, and wood debris, few works have studied the effects of riparian vegetation on the dispersion coefficient in transversally non-uniform streams. Here, a quasi two-dimensional model is proposed to evaluate the transverse profile of the depth-averaged velocity in the presence of any vegetation distribution along the riparian transect. Once velocity profile is obtained, the dispersion coefficient is evaluated and the remarkable role of vegetation is shown. Both the velocity profile and the dispersion coefficient have been validated using our new experimental results and literature data. The work highlights the importance of taking into account the presence of vegetation along river banks. The estimation of the longitudinal dispersion in vegetated rivers can be affected by as much as 70–100% compared to the case without vegetation.