Directions

Natural Resources Research -     

青藏地区城镇开发方向

文章通过对青藏地区域镇发展特征的研究，分析了对影响青藏高原地区城镇发展的主要因素如自然条件、交通条件、资源开发条什、经济条件和社会条件等。在西部大开发的背景下，提出符合青藏高原地区发展条件与环境的城镇开发方向。     

Primacy or Pluralism: Future Directions in Economic Geography

Rates of geographical mobility vary greatly, and fairly predictably, across the life course. Our analysis of special county-to-county migration tabulations of Census 2000 data discloses that, when flows are disaggregated by age, radically different patterns of net population redistribution are taking place upward and downward within the national urban hierarchy. The movements at the late-career, empty-nester, and retirement stage are the most “demographically effective” or unidirectional. The elderly fleeing large metropolitan areas have been congregating in micropolitan and rural counties with special climatic and other natural amenities. The opposite net flow is found for younger adults, who have been flocking into megametropolitan conurbations. At the midcareer stage, the net movement is from larger to medium metropolitan areas. We detail the age articulation of county-to-county migration flows with novel graphical portrayals and statistical measures. We give some thoughts on the relationship between intergenerational dependency and migration trends, and we speculate about whether the current patterns of age-articulated movement up and down the urban hierarchy will continue as the baby boom retires and the echo cohorts come of age.     

复杂风况条件下戈壁输沙量变化规律的研究

 戈壁输沙量与输沙势的定量关系一直是风沙地貌及风沙工程的关键科学问题之一。对莫高窟顶戈壁输沙量的长期监测（2008年5月至2009年4月）结果表明,窟顶戈壁输沙势为129VU,窟顶北侧的总输沙量约905 kg·m-1左右。其中,偏东风输沙量达500 kg·m-1,偏西风输沙量达320 kg·m-1。当风速大于11 m·s-1时,戈壁风沙发生长距离的输送,偏西风可将265 kg·m-1的沙量输送到窟区,偏东风可将410 kg·m-1的沙量吹回到鸣沙山。根据本区偏东风强盛,且偏东风戈壁输沙量大于偏西风输沙量的特点,提出了以固为主,输导结合的莫高窟风沙防治的主导思路。认为在窟顶构建一个既能阻截沙物质,又能对阻截的沙物质进行输导的人工戈壁床面是完全可行的。     

基于地标的行人导航路径引导方法

为了生成符合行人认知习惯的路径引导信息,以降低其在寻路过程中的认知压力并减少错误的寻路决策,提出一种基于地标的行人导航路径引导方法。该方法引入地标信息并建立空间对象间的可视关系,在此基础上使用方向模型和描述句法生成描述词和描述短语。随后提出了基于NLRP的全局路径描述算法和局部路径引导算法。前者提取中继目的地和途经地标,使用句法模式生成全局路径描述,为行人提供先验路径知识;后者判断行人当前位置,提取相关地标并结合句法生成对应位置的引导信息,辅助行人的寻路行为。最后,以北京林业大学校园为实验区域,验证了方法的可用性。     

Spatiotemporal Variation of South African Jobless Trends: Policy Directions

The need to understand the spatiotemporal change in South African unemployment trends underlies this research. The country has undergone significant socioeconomic change since the fall of apartheid in 1994. Not only has the labor market expanded, but unemployment has also increased. This necessitates a detailed spatial understanding to ensure effective policies at the municipal level to address unemployment. A database of unemployment statistics at the municipal level between 1991 and 2007 was created and used to spatially group municipalities. The results showed that metropolitan municipalities had unique unemployment characteristics and, contrary to findings elsewhere, an overall decrease in the dissimilarity between the unemployed and employed took place after 1991. Therefore, policies should promote economic growth and skills development in municipalities where education levels are low.