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71.
Cycle mode share increase is widely desired, but highway design practitioners lack the numerical tools to deliver infrastructure, instead relying on design standards and intuition, with little literature basis. As a case in point, the US Highway Capacity Manual (which is well used internationally) has developed levels of service for cycle infrastructure that are, at their core, based on an assumption of noninteraction between multiple cyclists. This paper uses a modified implementation of the Social Force Model to test the validity of this assumption. Necessary changes such as the consideration of acceleration characteristics and minimum maintainable speed are included. The resulting model produces valid outcomes in keeping with established traffic flow properties, reflecting three-phase traffic flow theory and the ability for the stochastic elements in traffic flow to cause flow breakdown. The developed simulation indicates that there is a fundamental difference in outcome if cyclists are assumed to have a fixed speed versus one they can change given their surroundings. This difference in outcomes is found to exist within the range of literature design flow capacities for bicycle infrastructure and also yields emergent outcomes that align closely with those known behaviors of highway vehicles, which intuitively transfer to cyclists. These findings reinforce the standing need for large-scale empirical studies to determine the basic numerical and behavioral parameters for cyclists, upon which all design ultimately rests. 相似文献
72.
73.
城市土地利用碳排放系统动力学仿真研究——以武汉市为例 总被引:1,自引:0,他引:1
研究目的:从系统角度分析土地、人口、社会、经济、能源对碳排放的影响作用,并对武汉市2017—2030年不同政策情景下的土地利用碳排放进行模拟,为其低碳发展战略和低碳土地利用规划提供决策依据。研究方法:系统动力学方法。研究结果:(1)建立的城市土地利用碳排放系统动力学模型是有效的;(2)按照目前的发展趋势,武汉市的碳排放总量将保持逐年攀升的趋势;(3)经济的快速发展对武汉市土地利用碳排放量的增加具有显著的影响作用;(4)调整土地利用结构、调整产业结构以及提高能源利用效率都能够有效的减少武汉市土地利用碳排放量,其中调整土地利用结构和调整产业结构的作用效果相对来说更加明显。研究结论:转变经济增长方式、升级产业结构、调整土地利用结构和积极研发先进的低碳科学技术是武汉市低碳发展的重要途径。 相似文献
74.
Agent-based models (ABMs) are becoming more relevant in social simulation due to the potential to model complex phenomena that emerge from individual interactions. In tourism research, complexity is a subject of growing interest and researchers start to analyse the tourism system as a complex phenomenon. However, there is little application of ABMs as a tool to explore and predict tourism patterns. The purpose of the paper is to develop an ABM that increases knowledge in tourism research by (i) considering the complexity of tourism phenomenon, (ii) providing tools to explore the complex relations between system components and (iii) giving insights on the functioning of the system and the tourist decision-making process. A theoretical ABM is developed to improve knowledge on tourist decision-making in the selection of a destination to vacation. Tourists’ behaviour, such as individual motivation, and social network influence in the vacation decision-making process are hereby discussed. 相似文献
75.
Jean‐François Coeurjolly Jesper Møller Rasmus Waagepetersen 《Revue internationale de statistique》2017,85(3):404-420
This tutorial provides an introduction to Palm distributions for spatial point processes. Initially, in the context of finite point processes, we give an explicit definition of Palm distributions in terms of their density functions. Then we review Palm distributions in the general case. Finally, we discuss some examples of Palm distributions for specific models and some applications. 相似文献
76.
为应对干旱、洪涝等降水事件给相关经济主体带来的风险,基于1953年1月至2016年12月福州市月均累积降水量数据,运用威尔克斯法对降水量进行建模,利用蒙特卡罗模法对降水期权进行定价从而得到降水期权价值,并提出发展我国降水期权的政策建议。 相似文献
77.
Consumer return rates have been steadily rising in recent years, resulting in growing costs for retailers who must manage the returns process and the disposition of returned products. This cost pressure is driven in part by extremely generous return policies, such as giving consumers a full refund upon return. Interestingly, this common retail practice of full refunds is inconsistent with the recommendations of many analytical models of returns, which nearly always show that a partial refund is optimal. Such inconsistencies between theory and practice might arise when the decision drivers included in the analytical models do not match the decision drivers in practice. It might also be the case that retailers are overly optimistic about the value that consumers assign to a full refund, and thus assume that the value of such a policy outweighs its costs. In this paper, we use data collected from eBay, where identical products are sold with different return policies, to investigate these open questions in the literature. We analyze both the return policy drivers from the retailer's perspective and the return policy value from the consumer's perspective. Our results suggest that the value of a full refund policy to consumers may not be as large as one might expect, and it also exhibits a large heterogeneity across buyers with different levels of online purchase experience. In addition, we provide empirical evidence for what has long been suspected by online retailers – that a non-refundable forward shipping charge quickly erodes any value that consumers assign to return policies. The generality of our results is limited by the fact that eBay differs from traditional retail contexts in many respects, including the fact that eBay buyers may not be representative of the general buyer population. However, our study of how eBay consumers value free returns provides new insights into an understudied area, and it can serve as a starting point for future studies of the value of return policies in other retail contexts. 相似文献
78.
《Futures》2016
There are many barriers and challenges associated with climate change communication focused on promoting community-based action for sustainable futures. Of particular interest is the challenge to embed community perspectives in a communication process of climate change solutions. In this paper we argue that 3D interactive simulations using design inquiry as a development process, can be an effective way of communicating climate change solutions and multiple community responses. People are more likely to engage with the challenges associated with complexity of climate change at the local level when their perspectives are integrated into viable and multiple pathways for action. Future scenarios of change processes situated in local experiences in compelling and interactive ways can be disseminated holistically by making links between scientific, social, political, economic and cultural elements. Design inquiry, as a research approach, integrates contextual knowledge into communication processes to aid imagining, re-thinking and reembodying viable pathways that explore the kinds of futures we collectively envision. This paper examines the contributions that design inquiry makes to climate change communication using an interactive simulation environment for designing futures. We discuss these ideas using the example of the Future Delta project, a virtual 3D environment that enables the exploration and simulation of multiple community-based climate change solutions in the Corporation of Delta, British Columbia. 相似文献
79.
P. Elhorst M. Abreu P. Amaral A. Bhattacharjee L. Corrado B. Fingleton 《Spatial Economic Analysis》2016,11(3):249-252
This editorial summarizes and comments on the papers published in issue 11(3) so as to raise the bar in applied spatial economic research and highlight new trends. The first paper proposes spatial and a-spatial indicators to describe the networks of airline companies around the world. The second paper sets forth a two-regime gravity-type model with an endogenous threshold parameter to assess the effect of labour market conditions on interregional migration flows. The third paper utilizes micro-data to explain student migration flows to higher education institutions. The fourth paper is among the first to make use of simulation-based location quotients in a multiregional input–output model. Finally, the last paper provides a purely economic–theoretical model on cooperative limit pricing in the context of spatial competition. 相似文献
80.
模拟土地利用空间格局分布规律对合理利用土地资源、制定土地利用规划、协调土地与经济、环境的关系具有十分重要的意义。土地利用格局存在空间异质性,对比不同地区格局特征规律对加深土地利用格局的认识具有重要意义。以邻接的湖北省宣恩县和咸丰县为研究对象,通过对比基于局地因子、自相关因子和邻域因子的3种Logistic模型的模拟参数的一致性和异质性来对比研究两地的格局分布规律。实验与分析结果表明,宣恩县和咸丰县的土地利用格局特征存在共同的驱动因子和聚集效应,具有共性;不同模型的模拟结果表明驱动因子在作用方向,大小方面存在差异,邻域因子在邻域尺度上表现出不同特征。研究结果对加深理解不同地区的土地利用分布格局特征的差异性,促进区域土地利用的规划、土地资源的合理开发与可持续发展战略的顺利实施具有一定的参考价值。 相似文献