Discussions on rail in urban areas and rail history

This paper includes discussions on rail in urban areas and railway history. More specifically commonly used terms and definitions for rail services, policy and practice in urban areas are discussed followed by an overview of railway developments around the world.     

Primary productivity and export fluxes on the Canadian shelf of the Beaufort Sea: A modelling study

We present a coupled sea ice–ocean-biological (including ice algae) model in the Arctic Ocean. The 1D model was developed and implemented on the Canadian Beaufort Sea shelf to examine the importance of different physical processes in controlling the timing and magnitude of primary production and biogenic particle export over an annual cycle (1987). Our results show that the snow and sea ice cover melt and/or break-up controls the timing of the phytoplankton bloom but primary producers (ice algae and phytoplankton) on the outer shelf are essentially nutrient limited. The total annual primary production (22.7 to 27.7 g-C m^? 2) is thus controlled by nutrient “pre-conditioning” in the previous fall and winter and by the depth of wind mixing that is controlled in part by the supply of fresh water at the end of spring (ice melt or runoff). The spring bloom represents about 40% of the total annual primary production and occurs in a period of the year when sampling is often lacking. Time interpolation of observed values to obtain total annual primary production, as done in many studies, was shown to lead to an underestimation of the actual production. Our simulated ratios of export to primary production vary between 0.42 and 0.44.     

Modelling the investment decision of the entrepreneur in the tanker sector: choosing between a second-hand vessel and a newly built one

It is often the case that the investor in the shipping sector faces the dilemma of investing in a second-hand vessel or building a new one. This happens because an active second-hand market for almost all kinds of vessels exists. We argue that one of the prime considerations for the investment decision should not be the price of the vessel per se, second-hand (SH) or newly built (NP) but

• ?(a)?the relative price ratio (SH/NP) second-hand price over the new building price and

• ?(b)?the movement of this ratio.

We investigate the determinants of this ratio across different vessel sizes in the tanker sector and show that it can be used as an effective tool in investment decision as well as in asset appraisal.

We employ monthly data between 1995 and 2006 for four different ship sizes–VLCC, Suezmax, Aframax and Handysize–and implement an error correction model.

The investment decision depends on a number of risk and return variables as well as the perceived speed of adjustment of the price ratio to its equilibrium level.

Overall we claim that the cyclicality of the shipping sector together with expectations formed by the agents operating in it (the entrepreneur, the ship-owner and the broker), determine the movement of the ratio and hence the decision of the entrepreneur.     

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.     

Social Networks of Alaska Fishing Communities

Fishing community social networks function as channels for transfer of fishery knowledge, resources, and business transactions that help mitigate risks and shocks associated with altered access to fishery resources. Research on such networks in Alaska is limited despite their cultural importance and community reliance on fisheries. We contribute to scholarship of fishery social networks by assessing Alaska fishing community perspectives of challenges related to fisheries policy and management, and the existing social networks that aid in overcoming these challenges. Our findings show that the greatest challenges fishing communities face pertaining to fishery management are high costs of participating in catch share programs, restricted subsistence fishing activity due to decline in salmon, and complex regulations. Social networks exist for coping with these challenges; fishery information, and resources such as food, fuel and medicines are shared between communities. However, networks for accessing fishery support services are centralized in fewer larger communities and hubs such as Anchorage. Smaller and remote communities are the most compromised in this regard given the distance they must travel to access fishery support services. Leveraging social networks for sharing resources and improving fishery support services in smaller communities will increase their adaptive capacity and ability to maintain participation in Alaska fisheries.     

Car ownership and access to jobs in Spain

The purpose of this paper is to assess the effect of urban structure on household car ownership in a context of rapid job and population decentralization. We capture the effect of urban structure through a measure of job accessibility to employment by public transport. An ordered probit explaining the number of cars per household is estimated as a function of individual, household and spatial variables. The data used in the analysis come from the Spanish Institute of Statistics’ 2001 Micro-census for the areas of Barcelona and Madrid. The results show that spatial variables play a significant role in explaining the probability of car ownership. We provide the car ownership elasticities with respect the job accessibility measure. Additionally, we carried out simulation exercises in which the expected number of vehicles decreases as accessibility improves.     

Cycling provision separated from motor traffic: a systematic review exploring whether stated preferences vary by gender and age

In this paper, we represent a systematic review of stated preference studies examining the extent to which cycle infrastructure preferences vary by gender and by age. A search of online, English-language academic and policy literature was followed by a three-stage screening process to identify relevant studies. We found 54 studies that investigated whether preferences for cycle infrastructure varied by gender and/or by age. Forty-four of these studies considered the extent of separation from motor traffic. The remainder of the studies covered diverse topics, including preferred winter maintenance methods and attitudes to cycle track lighting. We found that women reported stronger preferences than men for greater separation from motor traffic. There was weaker evidence of stronger preferences among older people. Differences in preferences were quantitative rather than qualitative; that is, preferences for separated infrastructure were stronger in some groups than in others, but no group preferred integration with motor traffic. Thus, in low-cycling countries seeking to increase cycling, this evidence suggests focusing on the stronger preferences of under-represented groups as a necessary element of universal design for cycling.     

A bi-criteria indicator to assess supply chain network performance for critical needs under capacity and demand disruptions

In this paper, we develop a supply chain/logistics network model for critical needs in the case of disruptions. The objective is to minimize the total network costs, which are generalized costs that may include the monetary, risk, time, and social costs. The model assumes that disruptions may have an impact on both the network link capacities as well as on the product demands. Two different cases of disruption scenarios are considered. In the first case, we assume that the impacts of the disruptions are mild and that the demands can be met. In the second case, the demands cannot all be satisfied. For these two cases, we propose two individual performance indicators. We then construct a bi-criteria indicator to assess the supply chain network performance for critical needs. An algorithm is described which is applied to solve a spectrum of numerical examples in order to illustrate the new concepts.     

基于粒子群优化算法的机场群航班优化配置研究

针对我国机场群发展不平衡、航线同质化程度高等问题,建立了以航班准点率、航空公司市场份额、旅客损失时间和航班功能定位指标最大化的航班时刻优化模型,将一级国际枢纽机场运行效果差的航班分配至周边机场.笔者在满足机场群内各机场起降容量限制、航班唯一性和航班连续性的条件下,设计改进的粒子群优化算法进行求解.以长三角机场群的航班时刻资源为例进行实例验证.研究表明:模型能够有效调整枢纽机场的低效航班至周边机场,使得机场群内各机场航班分布较为均衡,有效控制各时段航班架次的变化趋势,优化效果显著.     

Modelling and forecasting the demolition market in shipping

ABSTRACT

We model the demolition market, an integral part of the international shipping industry. It is shown through the implementation of a Vector Autoregressive (VAR) model that international steel-scrap prices contribute decisively towards price discovery in the ship-demolition industry. Our finding is explained and attributed to the fact that the growth models of Southeast Asian countries, where the ship-demolition market is primarily located, rely on scrap metal imports. These are mainly obtained from the developed economies rather than the recycling of vessels. We then proceed to test the forecasting ability of our model and use it for price prediction in the ship-demolition market. We establish that it provides the decision-makers with a useful prediction tool which enables all stakeholders involved, the ship owner, the recycler and the cash buyer alike, to gain valuable insights of the underlying trend in the sector.