新能源汽车消费者购买意愿调查

<正>虽然政府频频出台新能源利好政策,希望刺激消费者购买欲望,但研究显示,仅靠政策单方面刺激很难完成到2020年累计销售500万辆新能源车的目标,需要地方政府、汽车OEM和电网公司共同致力于推动新能源汽车的成功发展,解决充电等难题,从根本上消除消费者的顾虑。"中国消费者对新能源汽车(NEV)的兴趣及购买意愿仍不足以实现中国政府新能源汽车销量的目标。"中国是全球最大的汽车市场,而汽车业如火如荼的发展也同时造成了大城市的严重交通拥堵和空气污染。随着城镇化进程的不断推进(城镇人口有望从2014年     

Exploring vessel-price dynamics: the case of the dry bulk market

We investigate second-hand vessel price heterogeneity. Based on a sample of 5,591 purchase and sale transactions in the dry bulk sector over the period 1998–2016, we deploy a nonparametric regression technique to assess the determinants of vessel price and vessel price variability. Next, we use quantile regression to estimate the effect of regressors (sources of heterogeneity) at different parts of the vessel price distribution. We find evidence that main sources of vessel price heterogeneity are the age of the ship (the older the vessel the higher its maintenance cost), the 3-month LIBOR (reflecting the cost of financing) and the annual charter rate (revenues from operation). Their influence is stronger at all higher quantiles (periods of expansion) and the median of the vessel price distribution.     

Mobile phone data in transportation research: methods for benchmarking against other data sources

The ubiquity of personal cellular phones in society has led to a surging interest in using Big Data generated by mobile phones in transport research. Studies have suggested that the vast amount of data could be used to estimate origin–destination (OD) matrices, thereby potentially replacing traditional data sources such as travel surveys. However, constructing OD matrices from mobile phone data (MPD) entails multiple challenges, and the lack of ground truth hampers the evaluation and validation of the estimated matrices. Furthermore, national laws may prohibit the distribution of MPD for research purposes, compelling researchers to work with pre-compiled OD matrices with no insight into the methods used. In this paper, we analyse a set of such pre-compiled OD matrices from the greater Oslo area and perform validation procedures against several sources to assess the quality and robustness of the OD matrices as well as their usefulness in transportation planning applications. We find that while the OD matrices correlate well with other sources at a low resolution, the reliability decreases when a finer level of detail is chosen, particularly when comparing shorter trips between neighbouring areas. Our results suggest that coarseness of data and privacy concerns restrict the usefulness of MPD in transport research in the case where OD matrices are pre-compiled by the operator.

     

Modelling Pseudocalanus elongatus stage-structured population dynamics embedded in a water column ecosystem model for the northern North Sea

This paper outlines an approach to couple a structured zooplankton population model with state variables for eggs, nauplii, two copepodites stages and adults adapted to Pseudocalanus elongatus into the complex marine ecosystem model ECOHAM2 with 13 state variables resolving the carbon and nitrogen cycle. Different temperature and food scenarios derived from laboratory culture studies were examined to improve the process parameterisation for copepod stage dependent development processes. To study annual cycles under realistic weather and hydrographic conditions, the coupled ecosystem–zooplankton model is applied to a water column in the northern North Sea. The main ecosystem state variables were validated against observed monthly mean values. Then vertical profiles of selected state variables were compared to the physical forcing to study differences between zooplankton as one biomass state variable or partitioned into five population state variables. Simulated generation times are more affected by temperature than food conditions except during the spring phytoplankton bloom. Up to six generations within the annual cycle can be discerned in the simulation.     

Overtaking assistant assessment using traffic simulation

This contribution presents the results of a microscopic traffic simulation study of the potential effects of an overtaking assistant for two-lane rural roads. The overtaking assistant is developed to support drivers in judging whether or not an overtaking opportunity can be accepted based on the distance to the next oncoming vehicle. Drivers have been found to consider this to be a difficult part of an overtaking manoeuvre. The assistant’s effects on traffic efficiency, driver comfort and road safety have been investigated using traffic simulation. The results indicate that this type of overtaking assistant can provide safety benefits in terms of increased average time-to-collision to the next oncoming vehicle during overtaking manoeuvres. This safety benefit can be achieved without negative consequences for traffic efficiency and driver comfort. A driver assistance system that supports the distance judging part of overtaking manoeuvres can therefore contribute to improved traffic conditions on the two-lane rural roads of the future.     

Inhalable railroad particles at ground level and subterranean stations - Physical and chemical properties and relation to train traffic

The paper compares PM10 concentrations in railroad environments with EU air quality standards and characterizes particle concentrations and particle properties in relation to train traffic. The results show that PM10 concentrations in ground-level railroad environments do not exceed the EU directive 24-h limit value, while on the platforms of the two subterranean stations PM10 concentrations were far above the outdoor limit value. Diurnal and weekly patterns in PM10 concentration could be identified, co-varying with train traffic intensity. The particle mass size distribution peaked at around 2-6 μm. The elemental composition of PM10 at the subterranean stations was dominated by Fe.     

Long-term trends in domestic US passenger travel: the past 110 years and the next 90

Based upon a long-term historical data set of US passenger travel, a model is estimated to project aggregate transportation trends through 2100. One of the two model components projects total mobility (passenger-km traveled) per capita based on per person GDP and the expected utility of travel mode choices (logsum). The second model component has the functional form of a logit model, which assigns the projected travel demand to competing transportation modes. An iterative procedure ensures the average amount of travel time per person to remain at a pre-specified level through modifying the estimated value of time. The outputs from this model can be used as a first-order estimate of a future benchmark against which the effectiveness of various transportation policy measures or the impact of autonomous behavioral change can be assessed.     

Fuzzy Logic in Automatic Transmission Control

One of the fastest growing areas in engineering is that of fuzzy logic based technology. This study focuses on the application of fuzzy logic in automatic transmission control of automobiles. The question when and how to apply fuzzy theory is discussed. The usage of fuzzy theory in different existing transmission control systems is summarized and analyzed. Further, the influence of providing road information is observed by modeling a driver's shift action on a winding road.     

Institutions Shaping Coastal Ecosystems: The Algarve Case

Water and land use have changed dramatically over the last thirty years in Southern European coastal zones. For climatic and economic reasons coastal tourism development is often accompanied by simultaneous intensification of agricultural activity. The literature highlights a number of emerging resource pressures. The intensity of land use, excessive infrastructure development, and overexploitation of water resources pose the primary problems. Unsustainable development is often ascribed to mal-performing institutions (e.g., environmental management and land use planning), but there is a lack of studies analyzing the way in which institutions contribute to the problem. We address this gap by devising an analytical strategy that combines function analysis with the analysis of governance structures, property rights, and actors. This strategy is applied to the analysis of changes in ecosystem functions of the Portuguese coastal zone of the Algarve between the mid-eighties and today. Based on the analysis we call for an improvement of the performance of formal institutions in the Algarve. Actors in charge of implementing reformed institutions have to be given the financial and human means to implement formal property rights. Furthermore, entitlements for resource exploitation and interconnected transactions should not anymore be taken for granted. Specifically, institutions to control land use should be made more effective and incentives, that exclusively promote development, such as the construction tax, need to be questioned.