Analyzing influence of bicycles on traffic flow using microscopic simulation approach

Mixed traffic consisting of cars and bicycles is a typical pattern of urban traffic in China. To study the impact of bicycles on traffic performance, a microscopic simulating model based on the principle of cautious driving and collision free was proposed. The interaction between cars and bicycles were described by lateral friction and overlapping driving. The dynamical features of speed and time-headway were investigated by numerical simulations. The results show that bicycles have a significant impact on travel speed and time-headway. The effect of bicycles can cause different results in the free flow phase and congestion phase respectively. The results also indicate the necessity to mitigate the interaction between motorized vehicles and non-motorized vehicles.

Cautiously Optimistic

THE recent World Bank report of the continent＇s economy, ＂Africa＇s Pulse＂ laid out a very optimistic path for 2012. Coming offthe back of an average 4.9 percent growth in 2011, Sub-Saharan Africa is poised for good economic times ahead,

Cautiously Optimistic

EACH new year promises much spirits are high, expectations large and friendships strengthened. By all accounts 2015 promises much for Sino-Affican cooperation. Admittedly, the threat of Ebola, as reported on extensively in this magazine during 2014, casts a pall of negativity and tragic consequences across the continent, most notably West Africa. This killer pandemic, coupled with the perennial threat of instability and terrorism that haunts Africa, poses the biggest threat to development and the economy of the continent this year. It is little wonder then that China and Africa acknowledge the need to tightencooperation in these areas.

An SQP Algorithm with Cautious Updating Criteria for Nonlinear Degenerate Problems

An efficient SQP algorithm for solving nonlinear degenerate problems is proposed in the paper. At each iteration of the algorithm, a quadratic programming subproblem, which is always feasible by introducing a slack variable, is solved to obtain a search direction. The steplength along this direction is computed by employing the 1∞ exact penalty function through Armijo-type line search scheme. The algorithm is proved to be convergent globally under mild conditions.

Interobserver error in grassland vegetation surveys:sources and implications

Aims Observer error is an unavoidable aspect of vegetation surveys involving human observers.We quantified four components of interobserver error associated with long-term monitoring of prairie vegetation:overlooking error,misidentification error,cautious error and estimation error.We also evaluated the association of plot size with pseudoturnover due to observer error,and how documented pseudochanges in species composition and abundance compared with recorded changes in the vegetation over a 4-year interval.Methods This study was conducted at Tallgrass Prairie National Preserve,Kansas.Monitoring sites contained 10 plots;each plot consisted of a series of four nested frames(0.01,0.1,1 and 10 m^(2)).The herbaceous species present were recorded in each of the nested frames,and foliar cover was visually estimated within seven cover categories at the 10 m^(2)spatial scale only.Three hundred total plots(30 sites)were surveyed,and 28 plots selected at random were resurveyed to assess observer error.Four surveyors worked in teams of two.Important Findings At the 10 m^(2)spatial scale,pseudoturnover resulting from overlooking error averaged 18.6%,compared with 1.4%resulting from misidentification error and 0.6%resulting from cautious error.Pseudoturnover resulting from overlooking error increased as plot size decreased,although relocation error likely played a role.Recorded change in species composition over a 4-year interval(excluding potential misidentification error and cautious error)was 30.7%,which encompassed both pseudoturnover due to overlooking error and actual change.Given a documented overlooking error rate of 18.6%,this suggests the actual change for the 4-year period was only 12.1%.For estimation error,26.2%of the time a different cover class was recorded.Over the 4-year interval,46.9%of all records revealed different cover classes,suggesting that 56%of the records of change in cover between the two time periods were due to observer error.

Convergence analysis of cautious control

In this paper, we present a theoretical analysis on stability and convergence of the cautious control, which has advantages over the traditional certainty equivalence adaptive control, since it takes the parameter estimation error into account in the design, and is also one-step-ahead optimal in the mean square sense under Gaussian assumptions.

Cautious Lending Growth

China’s bank credit hit a record high in the first quarter, boosted by the 4-trillion-yuan ($585-billion) stimulus plan, indicating a faster economic recovery in China compared with other countries. But Ba Shusong, Deputy Director of the Research Institute of Finance under the Development Research Center of the State Council, describes China’s bank credit supplies as "excessively accommodative" from January to March.

Cautious U.S.Sees Little Threat From Euro

欧元伴随1999年新年钟声而诞生。她在世界各地的国际外汇交易市场的亮相的消息成为新闻传媒的一个亮点。1999年1月4日上海一家大报的头条新闻是:上海金融界“欧元总动员”。打开1999年1月5日清晨的Internet,首先映入眼帘的消息是:欧元闪亮登场,美元不见惊慌。这篇文章写得精彩,信息丰富。美元,在本文称为“the worl’s most sought-after reserve currency”,对于欧元的面世,自然别有一番滋味在心头。这种微妙的心情在本文表现得淋漓尽致。当然,在种种复杂的情绪中,文章披露的两条倒也不无道理: 1....Europe might turn its back on(不理睬)Problems elsewhere in theworld economy as it concentrates on making its unprecedented currency unionwork. 2....the focus on the euro must not deflect(使偏斜)from structuralreforms to reduce sky-high unemployment rates m much of Europe. 美国人的担心(The euro will start to challenge the dollar as the world’slead currency)是否会成为现实,何时会成为现实。国人尚须拭目以待。现在就下结论,未免为时过早。 此外,本文有几处措辞极为成功,读者不妨细读慢赏。】