高速公路高填方路基沉降量的神经网络预测

利用BP神经网络较强的高次非线性映射能力和学习功能 ,建立了基于人工神经网络的高速公路路基沉降量的预测模型。该模型依据现场实测资料 ,避免了计算过程中各种人为因素的影响。通过对某高速公路高填方路基沉降量的现场监测成果的学习与预测检验 ,证明其预测精度与适用性良好 ,具有较大的工程实用价值     

Offshore wind farms as productive sites or ecological traps for gadoid fishes? – Impact on growth,condition index and diet composition

With the construction of wind farms all across the North Sea, numerous artificial reefs are created. These windmill artificial reefs (WARs) harbour high abundances of fish species which can be attracted from elsewhere or can be the result of extra production induced by these wind farms. To resolve the attraction–production debate in suddenly altered ecosystems (cf. wind farms), the possible consequences of attraction should be assessed; thereby bearing in mind that ecological traps may arise. In this paper we investigated whether the wind farms in the Belgian part of the North Sea act as ecological traps for pouting and Atlantic cod. Length-at-age, condition and diet composition of fish present at the windmill artificial reefs was compared to local and regional sandy areas.Fish data from the period 2009–2012 were evaluated. Mainly I- and II-group Atlantic cod were present around the WARs; while the 0- and I-group dominated for pouting. For Atlantic cod, no differences in length were observed between sites, indicating that fitness was comparable at the WARs and in sandy areas. No significant differences in condition index were observed for pouting. At the WARs, they were slightly larger and stomach fullness was enhanced compared to the surrounding sandy areas. Also diet differed considerably among the sites. The outcome of the proxies indicate that fitness of pouting was slightly enhanced compared to the surrounding sandy areas. No evidence was obtained supporting the hypothesis that the WARs act as an ecological trap for Atlantic cod and pouting.     

Use of Gene Expression Programming in regionalization of flow duration curve

In this paper, a recently introduced artificial intelligence technique known as Gene Expression Programming (GEP) has been employed to perform symbolic regression for developing a parametric scheme of flow duration curve (FDC) regionalization, to relate selected FDC characteristics to catchment characteristics. Stream flow records of selected catchments located in the Auckland Region of New Zealand were used. FDCs of the selected catchments were normalised by dividing the ordinates by their median value. Input for the symbolic regression analysis using GEP was (a) selected characteristics of normalised FDCs; and (b) 26 catchment characteristics related to climate, morphology, soil properties and land cover properties obtained using the observed data and GIS analysis. Our study showed that application of this artificial intelligence technique expedites the selection of a set of the most relevant independent variables out of a large set, because these are automatically selected through the GEP process. Values of the FDC characteristics obtained from the developed relationships have high correlations with the observed values.     

基于小波包和空间相关性分析的人工地震波仿真技术

考虑强震作用下地震动参数的空间相关性,是生命线工程、道路、桥梁等呈空间分布的大型结构抗震设计的重点问题。由于强震观测历史和观测设备的限制,符合设计标准的地震波较为匮乏。因而,人工地震波成为结构抗震时程计算分析的一个重要技术。小波包技术将地震波进行时域和频域分解及合成并通过区域化的强震记录,得出小波包参数在时域和频域的统计特征及其空间相关性。进一步采用克里格插值法对无观测记录场址的地震动小波包参数进行最优估计,从而合成人工地震波。能较好地模拟人工地震波的区域空间相关特征,将为重大工程结构的防灾抗震仿真计算和动力优化设计提供实用可靠的地震波输入。     

物理探测手段在地震安全性评价中的具体运用

结合3个工程实例,对地球物理探测手段在地震安全性评价中的应用进行分析和探讨,以便为今后地震安全性评价工作开展活断层探测提供参考。浅层人工地震法和高密度电法以其观测结果直观、高效、方便、经济等特点成为活断层物理探测手段首选。两种手段对于探测环境以及精度要求可以优势互补,在活断层探测结果的判断方面可以相互验证。     

Changes in the epipelic diatom assemblage in nutrient rich streams due to the variations of simultaneous stressors

Benthic diatoms are often used for assessing environmental conditions, such as water quality and habitat conditions in stream and river systems. Although laboratory experiments have shown that each diatom species have different levels of tolerance to different stressors, few studies have been conducted in laboratory settings that analyze the responses of the diatom assemblage to the effects of multiple simultaneous variables. The aim of this study was to evaluate some structural responses (such as species composition and diversity) of the diatom assemblage on a short time scale to the effects of the simultaneous increase in four variables that are directly linked to the environmental changes affecting the Pampean streams: turbidity, nutrients (phosphorous and nitrogen), water velocity and temperature. To this end we conducted a five-week laboratory experiment using artificial channels where we simulated two environmental conditions (LOW and HIGH) employing epipelic biofilm from a mesotrophic stream. The results obtained in the experiment show that the structure of the diatom assemblage in the epipelic biofilm is affected by the simultaneous modification of temperature, water velocity, nutrient concentration and turbidity. These modifications in the assemblage included moderate decreases in diversity, small decreases in the proportion of species sensitive to eutrophication and saprobity, moderate increases in the IDP (Pampean Diatom Index) values and moderate changes in the percentages of the stalked growth-forms. The relative abundance of species such as Luticola mutica, Navicula cryptocephala and Navicula lanceolata were negatively affected by both treatments; other species such as Planothidium lanceolatum, Caloneis bacillum, Encyonema minutum, Humidophila contenta, Luticola kotschyi, Nitzschia amphibia, Navicula veneta, Pinnularia subcapitata var. subcapitata were positively affected by the HIGH treatment; and Nitzschia fonticola was positively affected by both treatments. The results suggest that, in the very short term of the bioassay conducted, the diatom assemblage can modify its structure to respond in a sensitive manner to the abrupt changes in multiple physical–chemical variables.     

陕西省气象短信产品优化分析与短信编辑

利用DMT探测平台对2009年3月11日山西一次云降水过程实施了综合探测,分析了此次云降水过程的宏微观物理特征。计算了云中过冷水含量距O℃层高度的垂直分布及其特征,并根据云雨粒子探测情况研究YAI降雨的可播度指标。     

专业气象服务产品自动制作与发布系统

利用地面雨滴谱的连续观测资料,可以分析降水特征和降水的形成机制。对于人工增雨的效果检验工作,雨滴谱资料的分析研究也具有重要的参考价值。目前,山西省人工降雨防雹办公室建设了6300km^2的人工影响天气效果检验示范基地,并且引进了4部德国OTT公司的Parsivel激光降水粒子谱测量系统,分别布设在太谷、汾阳、介休和祁县,这为进行雨滴谱观测研究提供了有利的条件。本文对Parsivel降水粒子谱仪的功能、产品以及在气象领域的应用作简单的介绍,旨在给我们使用此仪器进行降水微结构特征研究提供参考。     

Market driven management of climate change impacts in the Spanish mussel sector

Mussel farming is the largest aquaculture activity in Spain both in volume and value, being a key pillar for the development of the coastal areas in Galicia (NW Spain), where this production is concentrated. The available scientific knowledge suggests that in the long term the primary productivity of the Galician estuaries will be reduced due to climate change. Consequently, adaptive management will be required to face this challenge. The impact of the likely production decrease will depend, among other factors, on the availability of substitutes, being their identification the main object of this research. So, it was analysed whether this markets are integrated or not through cointegration tests, finding that only the French and the Spanish markets are partially integrated. This implies that since very little substitutes are available for the Galician fresh mussels, decreases in production will not necessarily affect producer's income, as prices increases will compensate the (eventual) reduction in volume. In terms of policy, this study suggests that market intelligence may contribute to an adaptive, pragmatic and flexible framework to face climate change impacts, avoiding too anticipated or blind responses that may result in economic, environmental and social costs.     

The impact of coastal defence structures (tetrapods) on decapod crustaceans in the southern North Sea

Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions.