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111.
Recent European Directives promoted the development of biofuels, requesting mandatory limits to their emissions ot greenhouse gases (GHG). Second-generation biofuels based on lignocellulosic biomass are prime candidates but their GHG emissions are variable and uncertain. Agro-ecosystem modeling can capture them and the performance of biofuel feedstocks.This study aimed at optimizing feedstock supply for a bioethanol unit in France, from agricultural residues, annual and perennial crops. Their productivity and environmental impacts were modelled on a regional scale using geo-referenced data on soil properties, crop management, land-use and future weather data. Several supply scenarios were tested. Cereal straw was the most efficient feedstock but had a low availability, and only miscanthus could meet the bioethanol plant's demand. Sorghum combined poor yields and high GHG emissions compared by miscanthus and triticale. A mix of three biomass sources used less than 3% of the regional agricultural land while abating GHG emissions by 60%.  相似文献   
112.
为分析孔隙分形维数和分形结构形式对粒子扩散特性的影响,通过生成分形结构模拟粒子在分形结构中的随机行走,探索分形介质中粒子扩散的运动规律.数值模拟结果显示,粒子在分形结构中的扩散行为受到起点位置、主通道和次通道形状及分形维数等因素的影响.  相似文献   
113.
Informed by research over the past two years and the work of colleagues in peer institutions, the IFI Irish Film Archive developed a six-year Digital Preservation and Access strategy which launched in 2014. Fundamental to this Strategy was the design and installation of digital archive tools for long term preservation and the redesign of workflow practices to facilitate accession and management of high resolution digital film and broadcast assets and associated metadata. This article outlines the steps taken and standards applied in developing a future proof digital audiovisual archive.  相似文献   
114.
分析了摆渡木马的工作原理和特点,提出了控制数据从计算机流向移动存储介质的解决方法。根据BLP模型的基本思想,提出了基于BLP模型的摆渡木马防御方案。在该方案中,根据内网或计算机中文件的重要程度,将文件分成不同等级;将用户对文件的访问权限也分成相应的不同等级;当用户对文件进行访问时,通过比较权限等级和文件等级来决定是否能读或写,读或写采用"下读上写"的策略。由于把移动存储介质的级别设为最低,所以该方案能有效的防止摆渡木马。  相似文献   
115.
Social media provide an online platform for enterprises to engage existing customers and attract new customers. Although social media can be easily set up at no cost, however, due to limited human and financial resources, many small businesses find it challenging to compete against large enterprises in social media use. While more and more small businesses have jumped on the bandwagon of social media in recent years, few studies investigated the social media strategies that can help small businesses to survive and even thrive against large competitors in the social media arena. Therefore, we studied 32 small pizzerias in a mid-size U.S. city in terms of their social media use for business. Our study found that small pizzerias emphasizing social media use on community relations and social responsibility tend to be more successful in attracting and engaging local customers. This study also sheds light on both effective strategies and successful practices of social media use by small pizzerias. The insights and recommendations identified from this study can help small businesses to enhance their social media competitiveness against large enterprises.  相似文献   
116.
Yelp, a social media site, undeniably has an influence on consumers' food choice in spite of its ability to reflect consumers' real voice being criticized. Since unhealthy food choices contribute to health problems, such as obesity and malnourishment, we attempted to examine these problems by better understanding consumers through health-related cues to action—a construct from the Health Belief Model (HBM)— on Yelp Honolulu's restaurant reviews. Our research revealed 13 main categories: Ingredient, Type of food, Taste, Lifestyle, Cooking, Option, Price, Portion, Well-being, Nutrition, Hygiene, Emotional attachment and indulgence, and Feeling. We argue that these categories may ultimately lead consumers to make healthier food choices. In search of the most appealing way to communicate with the target group, underlying concepts that derived from these categories can be tested. Marketers in food industry (or public health policy-makers) can craft their strategies for healthy food brands/products (or healthy eating scheme) based on the concept test research. Moreover, Yelp can apply these insights in the development of their algorithm and filter system in order to help consumers find healthy food if they wish to do so. Restaurants can also improve their strategy, menu, and communication execution to meet the growing demands of health conscious consumers.  相似文献   
117.
This paper outlines the major motivating factors concerning a novel collaborative project between Edinburgh College of Art and Edinburgh Virtual Environment Centre. The Tacitus project will investigate the use of multi-modal virtual environments, specifically, the haptic (touch) modality, with regards to the creative processes employed by designers working within the field of applied arts. The salient areas of research are described, and the methods by which information regarding these areas will be obtained are considered. Initial investigations have revealed a strong need to mimic the traditional applied artists' workspaces, with co-location of visual and haptic cues a priority.  相似文献   
118.
This essay begins with discussion of four relatively recent works which are representative of major themes and preoccupations in Artificial Life Art: ‘Propagaciones’ by Leo Nuñez; ‘Sniff’ by Karolina Sobecka and Jim George; ‘Universal Whistling Machine’ by Marc Boehlen; and ‘Performative Ecologies’ by Ruari Glynn. This essay is an attempt to contextualise these works by providing an overview of the history and forms of Artificial Life Art as it has developed over two decades, along with some background in the ideas of the Artificial Life movement of the late 1980s and 1990s.1 A more extensive study of the theoretical history of Artificial Life can be found in my paper ‘Artificial Life Art—A Primer’, in the Proceedings of DAC09 and also at http://www.ace.uci.edu/Penny. Excerpts from that essay are included here.   相似文献   
119.
收集国内、外有关资料,并结合潘家口水库现场围隔实验,主要从实验室内研究水体、野外围隔水体及天然水体三个方面,对浮游植物叶绿素a含量与生物量间的相关性进行探讨。结果表明:在实验室条件下,叶绿素a与生物量一般呈显著正相关关系,但当优势藻种发生明显变更时,二者相关性不明显甚至不相关;现有资料显示,野外围隔实验水中,叶绿素a与生物量一般呈显著正相关。在天然水体中,叶绿素a与生物量可能相关或不相关。叶绿素a与藻密度的关系将在续文中予以讨论。  相似文献   
120.
分析和比较了几种典型的P2P流媒体模型,介绍了P2P流媒体不同模型常用的数据调度算法,并指出了基于应用层多播的树模型和基于Gossip协议的网状模型的区别,最后指出了P2P流媒体的研究方向。  相似文献   
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