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121.
X. D. Wu S. G. Zuo L. Lei X. W. Yang Y. Li 《International Journal of Automotive Technology》2011,12(5):671-677
The purpose of this study was to effectively identify parameters for a LuGre friction model based on experimental measures.
In earlier work related to this study (Yang et al., 2009), which was based on the characters of polygonal wear (Sueoka and Ryu, 1997), we showed a frictional vibration model
for a mass on a moving belt. This model reflected lateral vibrations caused by velocity and toe-in angle. An important aspect
of the present study is the improved friction model. A previous friction model, which divided the process into four parts,
expressed the sable excited vibration well but failed to reflect the hysteresis loop change when vehicles accelerated or decelerated
continuously. A LuGre friction model can solve this problem, but several model parameters must be obtained experimentally.
We measured contact width and length of tires as vertical pressure changed; this provided a theoretical basis for apparent
stiffness of a unit of tire tread. Based on tire data from Bakker E’s article in a SAE paper from 1987, we identified the
Stribeck exponent and Stribeck velocity in LuGre. Then, the results were implemented in a vibration system that verified the
rationality of the data. 相似文献
122.
Seaport research: A structured literature review on methodological issues since the 1980s 总被引:1,自引:0,他引:1
Su-Han Woo Stephen J. PettitDong-Wook Kwak Anthony K.C. Beresford 《Transportation Research Part A: Policy and Practice》2011,45(7):667-685
This study aims to investigate how seaport research has been conducted from the methodological perspective. To this end, this study reviews published port literature for the last three decades (1980-2000s). The investigation primarily categorises the literature according to various methodological issues such as research paradigm, research strategy, base-disciplines, research methods and analysis techniques in order to provide meaningful implications on methodological evolution in seaport research for the period. This study suggests methodological bias in port research to a positivistic paradigm, following a quantitative trajectory moving from conceptual to empirical studies. In addition, the increased use of mathematical modelling and advanced statistical analysis methods is clearly observed. The introduction of advanced analytical tools used in other academic disciplines facilitates discussions in particular research area and amplifies the literature in those areas. This paper also suggests research gaps from the methodological perspective and implications for future port research. 相似文献
123.
John K. Stanley David A. Hensher 《Transportation Research Part A: Policy and Practice》2011,45(8):789-801
Building on a growing research foundation, transport policy makers have begun to associate the ability to be mobile with having a role in the facilitation of social inclusion. However, the further connection to well-being is not as well understood. This paper explores the association between a person’s travel patterns, their risk of social exclusion and self-assessed well-being. Key influences on social exclusion are discussed, with trip making emerging as a significant influence. Trip making is not a significant direct influence on well-being but does exercise an indirect influence through the impact on risk of social exclusion. The modelling process enables a value for additional trips to be estimated, the value being about four times the values derived from conventional generated traffic approaches. Similar high values are found in separate metropolitan and regional case studies, confirming the significance of the results. 相似文献
124.
通过对交通拥堵进行反思,认为交通拥堵是充满活力的成功城市的伴生品,应从不同角度考虑拥堵问题.提出了十项有别于传统观点的提议,主要包括:机动性至关重要,交通拥堵是社会、经济活力的象征;道路扩容效果短暂,并会诱发潜在需求,但仍可带来一定的社会、经济效益;土地使用对出行行为的改变需要长期的努力;紧凑型发展会加剧交通拥堵;降低... 相似文献
125.
126.
H. D. Smith 《Maritime Policy and Management》2013,40(6):351-376
The problems associated with hydrocarbon extraction in the EEZ are discussed under the headings of resources and environment, technology and the industrial structure, government management, decision-making, and policy formulation. Policy areas identified include boundary delimitation relative to resources, environment and technology, co-ordination and decision-making machinery, relationships with UK and EEC energy policies, and regional planning of the sea and coastal areas used by the off-shore industry. 相似文献
127.
128.
Short sea shipping has begun to receive attention from governments worldwide, as they seek to reduce traffic congestion and greenhouse gases. Despite a long coastline and its interest in international maritime affairs, the Canadian government had, until 2003, placed greater emphasis on resolving the issues of other transport modes. In July 2003, Canada and the United States signed a Memorandum of Cooperation on Sharing Short Sea Shipping Information and Experience. Subsequently, the federal government embarked on an assessment of short sea shipping through a series of workshops. This paper explores the key issues with respect to further development of short sea shipping from a Canadian perspective. It examines the critical limitations and impediments to further growth of short sea services in Canada and trans-border trade with the USA, and identifies a number of questions Canadian policymakers need to answer. 相似文献
129.
130.
Ioannis K. Chatjigeorgiou Spyros A. Mavrakos 《Journal of Marine Science and Technology》2007,12(4):218-231
This work considers the second-order sum-frequency diffraction problem for a stationary truncated surface-piercing circular
cylinder in bichromatic waves. The solution method was based on a semianalytical formulation of the second-order sum-frequency
diffraction potential. The boundary conditions were properly satisfied by introducing the “locked” and the “free” wave components
of the nonlinear velocity potential. The method was validated by comparing the calculated results with numerical data previously
reported by other authors. Particular attention was paid to the second-order sum-frequency heave forces and the change in
the wave run-up configuration due to the existence of the lower fluid domain underneath the truncated cylinder. 相似文献