Active Roll Control for Passenger Cars

The development of a mathematical model of a limited bandwidth hydro-pneumatic suspension that is incorporated into a vehicle handling model is described. The combined model is used to evaluate a suitable control strategy for eliminating body roll during a cornering manoeuvre. The philosophy behind the roll control strategy has been to use feedback measurements of the body motions which do not compromise the ride control. A study of the influence of the position of the body motion feedback transducer on the effectiveness of the system to reduce the body roll is presented. Non-linear modelling of the suspension components for a 0.8g cornering manoeuvre has revealed performance limitations. Conclusions are drawn as to the effectiveness of the control scheme.     

可持续交通——各方观点和长期挑战

从交通研究者和实践者的角度出发,以可持续交通这一概念为中心展开讨论。可持续交通宽泛地反映了可持续发展在交通领域的原则。随着可持续性这一概念的外延逐渐扩大,在它的定义、应用和价值取向上出现了不同观点。着重讨论可持续交通,以及如何理解和运用可持续交通,包括:1)将可持续性或者可持续发展作为一个整体的概念,包括关于可持续性的不同方法和定义之间的冲突;2)对可持续交通以及交通领域对其理解的探索;3)使用指标来实现可持续性的应用。然后识别了通往可持续交通之路的若干挑战,包括缺乏清晰定义、可持续性的固有冲突、可持续发展的跨领域本质、各种工作框架和指标体系、可持续发展的政治因素和交通领域实践中的不同观点。基于在该课题上的研究积累,总结解决这些问题的工作框架,提出因地制宜、注重结果、整体的方法来解决可持续交通中的挑战。     

Learning from Ecosystem-Based Management in Practice

We explore how marine ecosystem–based management (EBM) is translated from theory to practice at six sites with varying ecological and institutional contexts. Based on these case studies, we report on the goals, strategies, and outcomes of each project and what we can learn from these efforts to guide future implementation and assessment. In particular, we focus on how projects dealt with the challenges of working across geographic scales and diverse governance arrangements. While we hypothesized that EBM in the United States would be distinct from EBM in developing countries due to differences in social and political factors, we found that sites faced similar challenges. Variation among sites appeared to be more closely related to the preexisting management context and the scale at which the projects began rather than to clear differences between the United States and developing country contexts. EBM project implementers were able to overcome many of these challenges by focusing on a limited number of specific objectives, starting at a small scale, pursuing adaptive management, and monitoring a diverse set of indicators. These findings are directly relevant to current and future EBM efforts in these and other places.     

Assessing the Impacts of Gender Integration in Ghana’s Fisheries Sector

Abstract

This article presents the results of an impact assessment of a component of a large scale USAID sustainable fisheries management project initiative aimed at integrating gender and strengthening the role of women in fisheries management in Ghana. The assessment is based on a literature review and qualitative field data collection. It assessed gender integration from three entry points: improving the Ghanaian policy environment for gender in fisheries, empowering women post-harvest processors, and engaging women gleaners in fisheries co-management. The assessment found that an important milestone was the adoption and implementation of the Ghanaian Fisheries Sector’s National Gender Mainstreaming Strategy in 2016. Summarizing the impacts on local post-harvest processors and gleaners, the assessment found that female post-harvest processors have increased capacity, confidence, and engagement in fisheries management. Gender mainstreaming efforts have succeeded in challenging cultural norms about women’s role in fisheries. Women have been exposed to sustainable fisheries management and are better equipped with the knowledge and leadership skills to advocate for good fisheries practices, which they actively demonstrate.     

Part I: Externalities and economic policies in road transport

Road transport imposes negative externalities on society. These externalities include environmental and road damage, accidents, congestion, and oil dependence. The cost of these externalities to society is in general not reflected in the current market prices in the road transport sector.An efficient mobility model for the future must take into account the true costs of transport and its regulatory framework will need to create incentives for people to make sustainable transport choices. This paper discusses the use of economic instruments to correct road transport externalities, but gives relatively more weight to the problem of carbon emissions from road transport, as this is particularly challenging, given its global and long-term nature.Economics offers two types of instruments for addressing the problem of transport externalities: command-and-control and incentive-based policies.Command-and-control policies are government regulations which force consumers and producers to change their behaviour. They are the most widely used policy instruments. Examples include vehicle emission and fuel standards in the US as well as driving or parking restrictions in Singapore. The implementation cost of these instruments to the government is small. Although from an economic perspective these policies often fail to achieve an efficient market outcome, the presence of political constraints often make them the preferred option, in terms of feasibility and effectiveness.Economic theory shows how policies, which affect consumption and production incentives, can be used to achieve the optimal outcome in the presence of externalities. Incentive-based policies function within a new or an altered market. We first examine incentive-based policies, which cap the aggregate amount of the externality, such as carbon emissions, by allocating permits or rights to the emitters. The emitters are then free to trade their permits amongst them. The permit allocation mechanism is important-although market efficiency would be satisfied by an auction, political influences usually favour a proportional allocation based on historic emissions. We discuss EU ETS as an example of a cap-and-trade system, however, no such policy for CO₂ emissions in road transport has been implemented anywhere in the world to date.Fiscal instruments are, like command-and-control, widely used in road transport, because they are relatively cheap and simple to implement. They include the use of taxes and charges in order to bridge the gap between private and the social costs and, in principle, can lead to an efficient market solution. Registration, ownership, fuel, emissions, usage taxes, and parking and congestion charges have been implemented in many countries around the world. On the other side of the spectrum, subsidies can be given to those scrapping old cars and buying fuel-efficient vehicles. Some cities, such as London, have implemented congestion charges and many states in the United States have introduced high occupancy lanes. Other interesting possibilities include pay-as-you-drive insurance and other usage charges. However, the size and scope of taxes and subsidies are determined by governments, and because of their imperfect knowledge of the market the outcome is still likely to be inefficient.Governments have many effective economic instruments to create a sustainable road transport model. These instruments can be used separately or together, but their implementation will be necessary in the nearest future.     

Coastal Livelihood Diversification as a Pathway Out of Poverty and Vulnerability: Experiences from Tanzania

Livelihood diversification can increase the number of activities generating income and is often adopted as a means to reduce vulnerability to risk and provide a pathway out of poverty. Previous empirical studies, however, have found that this diversification carries no guarantee of success. This study examines the impacts of investments in conservation-based enterprises and micro-credit interventions implemented in coastal Tanzania. Project beneficiaries (n = 178) and non-beneficiaries (n = 117) from seventeen communities surrounding Saadani National Park and the Menai Bay Conservation area were surveyed in 2013, to gather quantitative and qualitative data on a suite of parameters including the number of livelihood activities, total annual income, and engagement in extractive activities. We found that the beneficiaries reported an average of 2.15 livelihoods, which was significantly higher than the 1.44 average reported by the non-beneficiaries. The beneficiaries also had significantly higher mean annual incomes than the non-beneficiaries as the former reported an annual mean income of US $2,076 while the latter reported US $646. The research found a complex relationship between occupational diversity and people's interactions with the environment and it is clear that livelihood diversification is not a blanket solution to reducing pressure on coastal resources. Another important finding from the research is that there are distinct differences between types of livelihood interventions and it is crucial to be clear about the goal of a livelihoods intervention. If the goal is diversifying livelihoods and strengthening resilience, then livelihoods that provide a small and steady income for many entrepreneurs may be enough. However, if the goal is to bring people out of a poverty trap, then it makes more sense to invest in livelihoods that bring in a higher income, even if that means reaching fewer beneficiaries.