Ecological requirements of Ostracoda (Crustacea) in three types of springs in Turkey

Seasonal occurrence of six ostracod species (Psychrodromus olivaceus, Potamocypris villosa, Ilyocypris inermis, Candona candida, Candona neglecta, and Cypridopsis vidua) varied from May 2003 to June 2004 in three types of spring (Limnocrene, Helocrene, Rheocrene). When I. inermis was only found in the limnocrene spring each month, P. olivaceus was common in all types of springs. The other four ostracods were found in the helocrene spring in fall, winter, and spring seasons. The unweighted pair group mean averages dendrogram separated three main clusters. The first cluster includes two species (C. vidua, C. candida) while I. inermis was found in the second cluster and P. olivaceus, C. neglecta, and P. villosa were found in the third. The occurrence of P. olivaceus and C. neglecta and P. villosa and C. candida was strongly correlated to each other (r=0.750 and 0.850, respectively). The Pearson correlation analyses showed a strong negative relationship between C. neglecta and water temperature (r=−0.607), but other species did not show any significant correlation to any of the environmental variables used (P>0.05). Canonical correspondence analyses (CCA) displayed all species closer to the center of the dendrogram, indicating high levels of species tolerances to environmental variables. Thus, the first axis of the CCA diagram explained 80% of the relationship between six species and five environmental variables.     

灰色系统GM(n,m)模型参数的递推估计和时变估计

本文给出灰色系统GM(n,m)模型参数的递推最小二乘估计和时变参数估计,前者的优点是可以避免反复求逆矩阵,因而使计算简便,同时克服了文献1中给出的估计方法当观察数据多、矩阵线数高、分配单元增加时,微型机容量不够的弱点,而且随着新数据的到来,通过递推算法自动对系统参数加以修正,提高了模型的自适应性;时变参数估计可以缩小系统的时变性与模型参数非时变性所产生的差异。     

用单桩沉降估算群桩沉降的计算方法

由于群桩沉降计算时参数的选取不易把握,而单桩沉降较易得到,找到一种用单桩沉降来代替群桩沉降的方法无疑会使得问题变得简单。单桩沉降由桩身压缩和桩端沉降组成。采用桩身线弹性的假定计算单桩桩身压缩,利用分层总和法计算单桩桩端沉降。同时在群桩沉降计算时考虑桩身压缩对沉降的贡献,并用承台下的平均附加应力乘以桩端荷载传递系数后作为桩端的附加应力。根据单桩和群桩沉降计算时的异同,提出了一种用单桩的沉降估算群桩沉降的方法,使得在群桩沉降计算时,参数选取较为容易,且计算较为简单。最后介绍了该方法在桥梁工程桩基础沉降计算中的应用。     

On selection of kernel parametes in relevance vector machines for hydrologic applications

Recent advances in statistical learning theory have yielded tools that are improving our capabilities for analyzing large and complex datasets. Among such tools, relevance vector machines (RVMs) are finding increasing applications in hydrology because of (1) their excellent generalization properties, and (2) the probabilistic interpretation associated with this technique that yields prediction uncertainty. RVMs combine the strengths of kernel-based methods and Bayesian theory to establish relationships between a set of input vectors and a desired output. However, a bias–variance analysis of RVM estimates revealed that a careful selection of kernel parameters is of paramount importance for achieving good performance from RVMs. In this study, several analytic methods are presented for selection of kernel parameters. These methods rely on structural properties of the data rather than expensive re-sampling approaches commonly used in RVM applications. An analytical expression for prediction risk in leave-one-out cross validation is derived. For brevity, the effectiveness of the proposed methods is assessed first by data generated from the benchmark sinc function, followed by an example involving estimation of hydraulic conductivity values over a field based on observations. It is shown that a straightforward maximization of likelihood function can lead to misleading results. The proposed methods are found to yield robust estimates of parameters for kernel functions.     

浅谈如何编好对外援助项目的工程概算

准确的工程概算和资料搜集对.外项目的顺利实施起着非常重要的作用,分析了编制.外工程概算的内容及方法,提出了做好编制工程概算应注意的问题。     

中国旅游业能源消耗与二氧化碳排放量估算(英文)

In 2009, nearly 900 million international tourist arrivals were counted worldwide. A global activity of this scale can be assumed to have a substantial impact on the environment. In this contribution, five major aspects such as the change of LUCC and the use of energy and its associated impacts had been recognized. Recently, the impact of tourism on environment and climate attracts the attention of international organizations and societies in pace with rapid development of tourism industry. Energy consumption and CO2 emissions in tourism sector are becoming a hot spot of international tourism research in recent five years. The use of energy for tourism can be divided according to transport-related purposes (travel to, from and at the destination) and destination-related purposes excluding transports (accommodation, food, tourist activities, etc.). In addition, the transports, accommodation and foods are related to many other industries which are dependent on energy. Thus, the estimations of energy consumption and CO2 emissions in tourism sector have become a worldwide concern. Tourism in China grows rapidly, and the number of domestic tourists was 1902 million in 2009. Energy use and its impact on the environment increase synchronously with China’s tourism. It is necessary to examine the relationship between energy use and CO2 emissions. In this article, a preliminary attempt was applied to estimate the energy consumption and CO2 emissions from China’s tourism sector in 2008. Bottom-up approach, literature research and mathematical statistics technology were also adopted. According to the calculations, Chinese tourism-related may have consumed approximately 428.30 PJ of energy in 2008, or about 0.51% of the total energy consumptions in China. It is estimated that CO2 emissions from tourism sector amounted to 51.34 Mt, accounting for 0.86% of the total in China. The results show that tourism is a low-carbon industry and also a pillar industry coping with global climate change, energy-saving and CO2 emission reduction. Based on this, the authors suggested that tourism should become an important field in low-carbon economic development.     

基于多源信息的区域尺度山地植被带数字化提取

山地植被带的提取及分析是地学和生态学研究的基础问题之一.利用野外点/线调查和历史文献资料,可以对局域尺度山体的植被带进行归纳和描绘,而在区域乃至全球尺度上更多依赖于学者的经验和知识.利用内蒙古大青山地区1∶100万植被图、1∶10万土地利用图、1∶25万DEM等,设计逻辑判别规则,提取典型的山地植被带斑块;然后基于贝叶斯识别算法,利用地形、水热和太阳辐射等因子对区域尺度山地植被带进行空间分布模拟,最终提取的植被带具有较高的精度,总体精度为74.53％,Kappa系数为0.69.研究表明,利用多源数据可以提取和模拟区域尺度山地植被带连续分布格局,中小比例尺空间数据的集成应用使得该方法的推广具有较大的可行性,为进一步获取大陆及全球尺度的山地植被带数据奠定了基础.     

中国近百年夏季雨量场及雨带类型恢复研究

文章将气象要素场转化为秩序统计量场,用ＥＯＦ迭代方案进行气象要素场的恢复研究．利用全国４２个站点１９５１～１９９５年夏季（６～８月）雨量场资料对１９０１～１９５０年夏季雨量场进行了恢复,并在此基础上用Ｂａｙｅｓ判别法对雨带类型进行了恢复．检验表明,所恢复的资料是可靠的．     

上海地区超长后注浆钻孔桩竖向承载力试验研究

依据上海地区某超高层商业建筑试桩的高吨位竖向抗压静载试验结果,通过对基桩的竖向极限承载力性状、桩身轴力传递特性以及桩侧阻力、桩端阻力发挥特性的分析研究,揭示了桩底注浆对基桩承载性状的影响情况,深入探讨了上海软土地区大直径超长后注浆灌注桩的荷载传递机理和竖向承载性状,提出了单桩承载力的估算方法。     

一种虚拟空间划分的室内指纹库定位方法

RSSI测量距离技术被广泛应用于距离定位的领域。针对传统的Zigbee指纹定位算法和复杂环境,文章提出了一种虚拟空间划分的Zigbee指纹库定位算法,其中包括虚拟空间划分最邻近定位算法、虚拟空间划分加权最邻近定位算法和虚拟空间划分贝叶斯定位算法。实验结果表明,在最优情况下,此方法能将定位误差抑制在1.50m。