The economics behind the awarding of terminals in seaports: Towards a research agenda

Terminal concessions in seaports have only recently gained interest in academic circles. Issues such as the allocation mechanisms (to be) used for granting those concessions, the determination of the concession term and concession fees, as well as the inclusion of special clauses aimed at assuring that the terminal operator will act in the interest of the port authority and the wider community, are increasingly relevant to both academics and the port industry. So far, insights from established economic theories have rarely been applied to terminal concessions in seaports. It, therefore, remains to be seen which kind of awarding procedure would be best for which type of terminal concession. This contribution provides a detailed overview of the different phases of the terminal awarding process, including a classification scheme for awarding procedures, and contains an extensive discussion on the economic issues that require further investigation. The paper concludes by proposing a comprehensive research agenda on the topic.     

Establishment of Community Managed Fisheries’ Closures in Kenya: Early Evolution of the Tengefu Movement

Community-based management (CBM) could be an essential tool to prevent the depletion of marine resources in the Western Indian Ocean region. In Kenya, political pressure to strengthen local governance, has led to adoption of CBM as a way of reducing over-exploitation and managing the competing uses and impacts on the marine environment. Several communities in Kenya have embraced CBM and have set aside or closed previously fished areas to enhance recovery of fisheries and biodiversity. These community fisheries closures (locally called tengefu), despite being degraded, may recover to finfish abundances and biodiversity levels similar to established MPAs or above thresholds for maintaining some ecological services. Communities see their direct involvement and control of these tengefu as more likely to result in benefits flowing directly to them. Community closures are also important for articulating and resolving community values and strengthening their management capacity. Here, we describe the evolution of the tengefu movement in Kenya and combine information from focus group discussions, interviews, underwater surveys and boundary marking to evaluate the current status, opportunities and challenges facing these tengefu. We show that in some cases community closures suffer from slow and incomplete national and local legislative processes, challenges to compliance, and weak management.     

出行方式与出发时间联合选择的分层Logit模型

基于随机效用最大化理论, 选取出行者特征、行程特性与出行方式服务水平作为效用变量, 以出行方式与出发时间作为选择肢, 构建了出发时间位于下层与出行方式位于下层的2种居民出行NL模型。分析了北京市居民出行样本数据, 并模拟了在早高峰时段对小汽车出行收取费用时, 小汽车出行者出行行为的变化。计算结果表明: 与传统MNL模型相比, NL模型具有更好的统计学特征, 调整后的拟合优度由0.338增大至0.404;在2种NL模型中, 出发时间位于下层的结构对样本数据的适应性更强; 当早高峰时段小汽车出行收取费用为5元时, 72.6%的小汽车出行者坚持原有出行方式与出发时间, 22.4%的小汽车出行者坚持小汽车方式, 但会改变出发时间, 4.8%的小汽车出行者改用公共交通方式, 但出发时间不变, 仅0.2%的小汽车出行者同时改变出行方式与出发时间; 当收取费用为10元时, 51.7%的小汽车出行者坚持原有出行方式与出发时间, 40.4%的小汽车出行者坚持小汽车方式, 但会改变出发时间, 7.9%的小汽车出行者改用公共交通方式, 但出发时间不变; 当收取费用为20元时, 27.5%的小汽车出行者坚持原有出行方式与出发时间, 60.6%的小汽车出行者坚持小汽车方式, 但会改变出发时间, 11.9%的小汽车出行者改用公共交通方式, 但出发时间不变。     

Fuel economy comparison of conventional drive trains series and parallel hybrid electric step vans

A hybrid electric vehicle (HEV) is a vehicle that combines a conventional propulsion system with an on-board rechargeable energy storage system to achieve better fuel economy than a conventional vehicle HEVs do not have limited ranges like battery electric vehicles, which use batteries charged by an external source. The different propulsion power systems may have common subsystems or components. The objective of this study is to compare the fuel economies of a conventional step van, a series hybrid electric step van (HESV), and a parallel HESV by calculating the fuel consumption using the ADVISOR software by NREL. We also showed the results of the vehicles in different driving cycles including the Central Business District bus cycles, the New York City Cycle, and the US EPA City and Highway cycles.     

Experimental studies on low pressure semi-direct fuel injection in a two stroke spark ignition engine

In this work a two-stroke scooter engine was modified to work with semi-direct injection of gasoline at a pressure of 8 bar from an injector in the cylinder barrel pointed toward the cylinder head. The influence of injection timing, injection pressure, spark plug location and air-fuel ratio, on performance, emissions and combustion characteristics has been investigated. In addition, a comparison has been made with manifold injection of gasoline on the same engine at a given speed and various outputs. A significant reduction in HC emissions and fuel consumption with no adverse effects on NOx emissions and combustion stability was observed. A small drop in power and increase in CO emission were observed disadvantages of the new injection system. Injection timing was found to be the most important factor and a balance between reduction in shortcircuited fuel by late injection, and time for mixture preparation by advancing the injection, was found to be essential.     

Creating bus timetables with maximal synchronization

This paper addresses the problem of generating a timetable for a given network of buses so as to maximize their synchronization. It attempts to maximize the number of simultaneous bus arrivals at the connection (transfer) nodes of the network. Transit schedulers, taking into account the satisfaction and convenience of the system's users, appreciate the importance of creating a timetable with maximal synchronization, which enables the transfer of passengers from one route to another with minimum waiting time at the transfer nodes. In this paper, the problem is formulated as a mixed integer linear programming problem, and a heuristic algorithm is developed to solve the problem in polynomial time. The efficiency of this algorithm, compared to optimal solutions, is illustrated through a series of examples.     

Approximations to the magic formula

Pacejka’s tire model is widely used and well-known by the automotive engineering community. The magic formula describes the brake force, side force and self-aligning torque in terms of the longitudinal slip and slip angle, plus several corrections. This paper uses approximation theory to obtain different types of approximations to the magic formula: rational functions (RA) resulting from the Remez algorithm, expansions in a series of Chebyshev polynomials (ACh), a series of Chebyshev rational polynomials (ARChPs), a series of rational orthogonal functions (ORF) and a series of ARChPs that result from grade-1 ORFs. The last expansion shows the fastest convergence and most effective computation. Jacobi rational polynomials can also be obtained to complement this expansion and facilitate fine-tuning in specific areas of the error curve. This work is complemented by obtaining the original rational approximations to the inverse tangent function, which take advantage of the curve symmetry to reduce the computation load and provide models that include the influence of the vertical load. The convergence properties of the development in series and the error values resulting from numeric examples for the three types of stress are shown. The proposed final ARChP expressions show very low error (1%) compared to the original magic formula. They can be computed 20 times faster; they can be evaluated, derived and integrated analytically easily; and their coefficients can be obtained from tests using common least-squares algorithms.     

Advances in port studies: the contribution of 40 years Maritime Policy & Management

Port economics, management and policy have progressively emerged as a distinctive research field, and a core part of maritime economics. This paper provides an analysis of all the 267 port studies published in Maritime Policy & Management (MPM) since its inception in 1973. This paper provides a content analysis for seven interrelated research theme categories including main research topics and methods, authorship distribution and citation counts. It is demonstrated that MPM played, and continues to play, a key role in publishing research on seaports. The published research increasingly applies established analytical frameworks to ports. The paper concludes with a discussion on current challenges for port-related research.     

Choosing Public Transport—Incorporating Richer Behavioural Elements in Modal Choice Models

The development of behaviourally richer representations of the role of well-established and increasingly important influences on modal choice, such as trip time reliability and accounting for risk attitude and process rules, has moved forward at a fast pace in the context of automobile travel. In the public transport setting, such contributions have, with rare exception, not been considered. In this paper, we discuss and empirically illustrate the merits of advanced modelling developments aimed at improving our understanding of public transport choice, namely the inclusion of reliability in extended expected utility theoretic forms, to recognize risk attitude and perceptual conditioning, the consideration of passenger crowding and its inclusion in linear additive models, and the role of multiple heuristics in representing attribute processing as a way of conditioning modal choice. We illustrate the mechanics of introducing these behaviourally appealing extensions using a modal choice data set collected in Sydney.     

Private Provision of Highways: Economic Issues

Abstract

This paper reviews issues raised by the use of private firms to finance, build, and/or operate highways—issues including cost of capital, level and structure of tolls, and adaptability to unforeseen changes. The public sector’s apparent advantage in cost of capital is at least partly illusory due to differences in tax liability and constraints on the supply of public capital. The evidence for lower costs of construction or operation by private firms is slim. Private firms are likely to promote more efficient pricing. Effective private road provision depends on well‐structured franchise agreements that allow pricing flexibility, restrain market power, enforce a sound debt structure, promote transparency, and foster other social goals.