Study of emerging air taxi network operation using discrete-event systems simulation approach

This research focuses on understanding the air taxi operations to determine the number of air taxis required to fulfill the demand for urban air mobility in New York City (NYC). We leverage the Define, Measure, Analyze, Design, and Verify (DMADV) framework and integrate it with the systems simulation approach. Upon investigation, we find that all the parameters linearly impact the vehicle utilization, while other measures are robust, specifically with respect to the seating capacity. It is also recommended to operate initially with 70 air taxis in NYC to achieve a trade-off between customer wait time and vehicle utilization. The proposed approach can act as a recommender system for air taxi companies.     

大断面强流变软岩硐室加固技术相似模拟试验研究

针对鹤煤九矿井下硐室出现浆皮开裂、底臌等类似现象,采用相似模拟的方法,以鹤煤九矿31采区避难硐室临近硐室群实际地质资料为基础,研究分析了给定应力环境下不同支护方式时硐室围岩的变形破坏情况、失稳过程。作者认为,随着顶部压力的逐渐改变,顶板裂隙逐渐增加,裂隙深度和宽度逐步增加,巷道出现离层、底鼓,进而呈现大面积破坏。该结果对区段巷道布置与加固方案优化有一定的参考价值。     

Economic Impacts of Improved Connectivity for ASEAN: An Application of the Geographical Simulation Model

We compare the prioritized projects of the Master Plan on ASEAN Connectivity (MPAC) and the Comprehensive Asia Development Plan (CADP) by utilizing the Institute of Developing Economies/Economic Research Institute for ASEAN and East Asia Geographical Simulation Model. The prioritized projects of the MPAC mainly focus on specific hard or soft infrastructure projects connecting one remote area of an ASEAN member state to another and thus fail to capture the full potential of the infrastructure because of neglected important links within a state. On the other hand, the CADP emphasizes the importance of economic corridors or linkages between a large cluster and another cluster. Our simulation analysis shows that CADP projects will result in an addition to gross domestic product (GDP) of $US 1544bn over the period from 2021 to 2030 (in 2010 dollars) or an impact on ASEAN countries that is 12 times larger than MPAC projects. The results strongly suggest that the CADP projects should be adopted and implemented to fully realize the potential economic growth of the ASEAN countries. Moreover, the CADP will contribute more to narrowing the development gaps among the ASEAN countries than MPAC prioritized projects.     

Designing futures: Inquiry in climate change communication

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.     

A Monte-Carlo approach to estimating the effects of selected airport capacity options in London

The issue of future airport capacity in London is currently the subject of much political debate in the UK. Although realistic estimates of the effects of capacity enhancement may be desirable, such estimates are difficult. Through the use of Monte Carlo simulation, this paper quantifies and compares the relative capacity enhancements that may be afforded by the construction of a new hub airport in the Thames Estuary, additional runways at Heathrow, Gatwick and Stansted and changes to operating practices at Heathrow. The simulations show that a new hub airport would be the most effective way to increase capacity, although the reported financial and environmental costs of such a development indicate a comparatively poor rate of return. Proposed new runways at Heathrow, Gatwick and Stansted and the removal of runway alternation at Heathrow provide more modest increases in capacity.     

基于多智能体的建筑业产业资质问题研究

由于目前关于建筑行业资质管理对建筑产业的有效性存在正反两方面不同看法,双方虽有定性理论分析和国外资质管理根据,但是无法说明资质管理对我国建筑产业整体收益具体影响,因而从个体企业行为角度出发,根据多智能体理论,使用Netlogo建模平台,建立中国建筑业的交易行为互动流程,模拟运行建筑产业执行或不执行资质管理的情况,观察并分析论证了资质管理有利于提高中国建筑产业收益能力。此外,在模拟过程中发现资质管理对产业结构也存在影响。     

Raising the Bar (3)

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.     

Stochastic seat allocation models for passenger rail transportation under customer choice

We study the seat allocation problem for passenger rail revenue management, in which a rail operator attempts to determine the optimal quantity of seats to be allocated to each cabin class for each train service. We formulate the problem with single-stage and multi-stage decisions as two stochastic programming models that incorporate passengers’ choice behavior. We transform the stochastic models into equivalent deterministic mathematical programs that are easy to solve. Then, we form a variety of seat allocation polices from the optimal solutions to the seat allocation models. A number of simulation tests are offered to test the policies.     

极软表土层支护技术研究

通过对回风斜井的围岩性质及巷道破坏原因分析,结合数值模拟,提出了U型钢支架与短锚杆全长锚固巷道底角加锚索并喷射混凝土封闭围岩支护治理方案。经实验表明,上述方案的实施取得了良好的支护效果。