基于偏好融合的群组推荐研究

传统的推荐系统主要针对单个用户,但随着社会和电子商务的快速发展,人们越来越多地以多个用户的形式一起参与活动,而群组推荐旨在为多个用户组成的群组提供服务,已成为当前研究的热点之一.针对目前群组推荐准确率低,群组成员之间偏好冲突难以融合的问题,本文提出了一种新的共识模型策略,融合了群组领袖影响因子和项目热度影响因子,基于K近邻为目标群组寻找邻居群组,借鉴邻居群组的偏好,设计了基于偏好融合的群组推荐算法.在MovieLens数据集上的实验结果表明,本文所提的融合策略较传统的偏好融合策略有着更优越的表现,推荐准确率（nDCG）的总体平均性能约提高13%,推荐列表多样性指标的总体平均性能约提高10%.     

The impact of offshore wind farms on beach recreation demand: Policy intake from an economic study on the Catalan coast

Offshore wind energy development can have major economic implications because of the potential impact on coastal recreation demand – particularly for countries that are characterised by high offshore wind power potential while also being popular tourist destinations. In this context, the impact of offshore wind farm projects on beach recreation demand in Catalonia (Spain) during the 2012 summer season was examined. A combined revealed and stated preference approach, which allows joint modelling of actual and hypothetical demands, was applied. The results demonstrate a significant welfare loss up to €203 million per season. The results further show that the installation of a wind farm mainly will cause a shift in trips to Catalan beaches without wind farms, which implies that the estimated negative economic impacts will occur mostly in areas where wind farms are located. From a political economy point of view, this may call for the design and implementation of re-distributive instruments to offset the negative impacts caused by wind farms.     

Autecology of Limnomysis benedeni Czerniavsky, 1882 (Crustacea: Mysida) in Lake Constance, Southwestern Germany

The Ponto-Caspian mysid Limnomysis benedeni was first recorded in Lake Constance in summer 2006, and a stable population developed at the site of discovery. Although this mysid is common in the Rhine and Danube rivers, little is known about its ecology and impact in systems of invasion. We investigated the autecology of L. benedeni in habitat-choice and food experiments. In the habitat-choice experiments, highly structured habitats, i.e., stones covered with zebra mussels (Dreissena polymorpha), macrophytes, and especially stonewort, were strongly preferred. In food experiments, L. benedeni fed mostly on food sources with a small particle size, e.g., biofilm on leaf litter, biodeposited material of zebra mussels, epilithon, and phytoplankton. We also compared the L. benedeni population data from Lake Constance with that from rivers. In Lake Constance, female L. benedeni were nearly 30% larger and carried more than three times more eggs in spring (9.4±0.6 mm and 28.4±5.7 eggs) than in summer (6.7±0.8 mm and 8.7±2.9 eggs). The mysids present in spring might be the generation that over-wintered; in summer, this generation was probably replaced by a new generation of smaller individuals. The large brood size and the detritivorous feeding strategy might allow L. benedeni to colonize Lake Constance rapidly.     

辽南丹东地区中生代金成矿的FIP的证据

辽南丹东地区产出有五龙、四道沟两个大型金矿床,两矿床与中生代燕山期三股流花岗岩体存在密切的空间华生关系。长期以来,对这一地区金的成矿作用时代存在有不同的认识,一种观点认为金的成矿作用只有一期,即中徨代（燕山期）;另一种观战认为金的成矿作用有两期,即元古代和中生代（燕山期）分别以四道沟金矿和五龙金矿为代表,作者利用流体包裹体面（ＦＩＰ）研究的新方法对金矿床及伴生花岗岩进行了研究。结果表明,三股流花岗     

公众对黑河流域生态系统服务消费偏好及支付意愿研究——基于选择实验法的实证分析

运用选择实验法研究了黑河流域居民对流域生态系统服务的消费偏好及其支付意愿,并结合Mixed logit模型和潜类别模型分别从连续和离散的视角对消费者偏好的异质性进行了检验和实证研究。研究发现：① 黑河流域居民对流域生态系统服务的改善存在显著的异质性偏好,且流域居民从流域水质改善中能获得最大的效用,生态导向型消费者对平均扬沙天气情况改善存在显著偏好,娱乐享受型消费者对流域休闲娱乐条件改善存在显著的偏好。② 黑河流域居民对河流水质、东居延海水面面积和休闲娱乐条件改善3个属性指标具有显著的支付意愿,且对河流水质改善的支付意愿最大,为133.91元/（a·户）。③ 黑河流域居民愿意为流域生态系统服务改善的整体支付意愿为473.16元/（a·户）。     

芜湖市城市居住区位研究

运用评价模型对芜湖市各个片区的居住区位进行了评价,利用问卷调查方式所获取的资料对芜湖市居民的居住满意度和择居意向进行了分析,并探讨了居住区位优势度对商品房价格的空间分异、居民居住满意度、居民择居偏好区位的影响。结果表明,处于芜湖市中心的城中片区在居住区位方面的优势最高;其次是镜湖北片区;再次是城南片区、城东片区、开发区片区;三山片区最次。可见对一个拥有中等规模,新区刚刚开发的城市而言,发展历程越久的片区,其区位优势越强,且商品房价格越高,居民的居住满意度越高,更成为居民理想的择居区位。     

武汉市蜜月旅游者行为特征与开发对策研究

蜜月旅游作为一种新兴的旅游产品,自进入中国市场以来发展迅速,引起了人们的广泛关注。在旅游经营中,了解客源市场旅游者的行为特征,对市场开发具有重要的意义。在综合分析国内外蜜月旅游研究现状的基础上,通过问卷调查的方式,对武汉市蜜月旅游市场进行了实证研究,揭示了武汉市蜜月旅游者具有出游时间长、消费能力强、偏好海滨型目的地等行为特征,并根据这些特征提出设计多样化产品、完善产业链、品牌化经营及加大宣传营销力度等具体开发对策。