More gray hair—but for whom? Scenario-based simulations of elderly activity travel patterns in 2020

This paper reports the results of a scenario-based simulation study to explore mobility effects of an aging society in the Netherlands. Four accumulative behavioral scenario variants, embedded in an economic and demographic scenario are used to simulate possible future activity-travel patterns, using the Albatross system as the simulator. The variants account for likely differences in activity-travel behavior between elderly today and elderly in the future. Trends ongoing over the last decade in the Netherlands suggest that future elderly need to work longer, change their activity pattern with most growth occurring in the social/leisure activity category, will try to avoid morning peak hours by rescheduling their activities and may introduce more spatial diversity in terms of their residence location. Results show that these behavioral and spatial changes lead to a significant increase in travel demands as well as temporal, spatial and modal shifts in mobility patterns. We discuss possible policy implications of these predictions and evaluate the specific strength of activity-based models for studies of this kind.

Foreland-based regionalization: Integrating intermediate hubs with port hinterlands

Development and changes in port hinterlands have received considerable attention as they represent substantial opportunities to improve the efficiency of global freight distributions. Port regionalization was a concept brought forward by Notteboom and Rodrigue (2005) to articulate the emerging port hinterland dynamics in light of containerization, supply chain management and the setting of inland terminals. This paper expands this concept by focusing on a particular dimension of the regionalization paradigm concerning the evolving role of intermediate hubs. It is argued that, in addition to hinterland-based regionalization, there is also a foreland-based regionalization where intermediate hubs capture a maritime hinterland. This intensity and viability of processes of foreland-based regionalization depend on multiple geographical, technical and market-related factors, and this paper identifies and analyzes these underlying parameters. By doing so, it assesses whether foreland-based regionalization is simply a transitional phase in port development or, alternatively, represents emerging functional characteristics of contemporary freight distributions.     

Structural changes in logistics: how will port authorities face the challenge?

The market environment in which ports operate has changed dramatically, and this continuous process of change raises questions on the role of port authorities. This paper discusses the impact of some structural changes in international trade, transport and shipping on strategic and operational issues in the framework of port management. The central hypothesis put forward is that a successful port (authority), like a successful actor, must be prepared to constantly adopt new roles in order to cope with the changing market environment. The content and strategic scope of these new roles are highlighted, especially with regard to the European container port system.     

Modelling Complex Activity‐Travel Scheduling Decisions: Procedure for the Simultaneous Estimation of Activity Generation and Duration Functions

Abstract

Activity generation is a key factor in individual's choices of trip frequency and trip purpose. This paper describes the results of an experiment conducted to estimate functions of several temporal factors on individuals' propensity to schedule a given activity on a given day. The theory on which the experimental design is based states that the probability of scheduling an activity is a complex and continuous function of how long ago the activity was lastly performed, the duration constraints for the activity and the amount of available time in the activity schedule of the day considered. Aurora, an existing model of activity scheduling, assumes S‐shaped utility functions for the history as well as the duration functions, whereas most time‐use studies assume monotonically decreasing marginal utilities. The stated‐choice experiment involves a range of flexible activities and a large sample of individuals to measure the utility effects of a set of carefully chosen levels for the factors and tests these specific assumptions. The results suggest that the amount of discretionary time on a day has no significant impact on the scheduling decisions provided that enough time is available for the activity. The effects of other factors are as expected and show diminishing marginal utilities. We find mixed evidence for an initial phase of increasing marginal returns as assumed in an S‐shaped function.     

Port Economics,Policy and Management: Content Classification and Survey

This paper presents a taxonomy and analysis of the content of published research in port economics, policy and management (port studies). The recent increase of these publications suggests a growing interest in the study of ports. However, the research characteristics and directions of this research field are unidentified. This paper provides a systematic analysis of port studies published during the period 1997–2008. A comprehensive cross-citation and analysis of the themes, approaches and findings of all 395 relevant journal papers identifies the extent to which the research field is maturing, and the leading papers. This paper also presents an extensive analysis of the content, based on the classification of all port studies into seven research themes. For each theme, research topics, widely used research questions, concepts and research methods and the most important research findings are discussed. Finally, we identify emerging research challenges and research questions that still need to be answered.     

Changing household car ownership level and life cycle events: an action in anticipation or an action on occurrence

This paper analyzes households’ decision to change their car ownership level in response to actions/decisions regarding mobility issues and other household events. Following recent literature on the importance of critical events for mobility decisions, it focuses on the relationship between specific events (e.g. childbirth and buying an extra car), rather than trying to explain the status of car ownership from a set of stationary explanatory variables. In particular, it is hypothesized that changes in household car ownership level take place in response to stressors, resulting from changed household needs or aspirations. The study includes a broad range of events. Apart from changes in work status, employer and residential location, it analyzes demographic events such as household formation and childbirth. Also, it scrutinizes the temporal sequence in which chains of related events are most likely to occur. To this end, data from a retrospective survey that records respondents’ car ownership status, as well as residential and household situation over the past 20 years are used. A panel analysis has been carried out to disentangle typical relationships. The results suggest that strong and simultaneous relationships exist between car ownership changes and household formation and dissolution processes. Childbirth and residential relocation invoke car ownership changes. Changes are also made in anticipation of future events such as employer change and childbirth. Childbirth is associated with increasing the number of cars, whereas the effect of employer change goes the opposite way. Job change increases the probability of car ownership change in the following year.     

The effects of social networks on choice set dynamics: Results of numerical simulations using an agent-based approach

Activity-based analysis has slowly shifted gear from the analysis of daily activity patterns to the analysis and modeling of dynamic activity-travel patterns. In this paper, we address one type of dynamics: the formation and adaptation of location choice sets under influence of dyad relationships within social networks. It extends the dynamic model developed in earlier work, which simulates habitual behavior versus exploitation and exploration as a function of discrepancies between dynamic, context-dependent aspiration levels and expected outcomes. Principles of social comparison and knowledge transfer are used in modeling the impact of social networks through information exchange, adaptations of spatial choice sets and formation of common aspiration levels. We demonstrate model properties using numerical simulation with a case study of shopping activities.     

控制底盘系统的噪声和振动问题

过去,偏重功能性的技术开发是可行的、甚至合理的。而时至今日,除价格、重量外,更多其它的标准变得日益重要,有时甚至能决定一个产品的市场成败。比如,盘式和鼓式制动器能造成许多噪声与振动现象,这些现象和声音可以描述为“颤抖”、“呜咽”、“尖叫”     

Port regionalization: towards a new phase in port development

Logistics integration and network orientation in the port and maritime industry have redefined the functional role of ports in value chains and have generated new patterns of freight distribution and new approaches to port hierarchy. Existing models on the spatial and functional evolution of ports and port systems only partially fit into the new freight distribution paradigm. This paper aims to add to existing literature by introducing a port regionalization phase in port and port system development. It is demonstrated that the regionalization phase and associated hinterland concepts demand new approaches to port governance and a functional focus that goes beyond the traditional port perimeter.     

The impact of low sulphur fuel requirements in shipping on the competitiveness of roro shipping in Northern Europe

Annex VI of the MARPOL Convention aims for a reduction in sulphur oxide emissions from ships. The limits applicable at sea in Emission Control Areas (ECAs) were reduced from 1.5% to 1% in 2010 and are planned to be further reduced to 0.1%, effective from 1 January 2015. This paper analyses the impact of the International Maritime Organization’s Tier II/III standards introduced by Annex VI amendments adopted in October 2008 on costs and prices of roro (roll on/roll off) traffic in the ECAs in North Europe and on the competitiveness of roro shipping in the ECAs compared to trucking. We demonstrate that the new Annex VI agreement may be quite costly for the participants in the shipping industry and will result in higher freight rates. Based on a detailed price analysis on modal competition between the roro/truck option and the ‘truck only’ option on thirty origin–destination routes linked to the ECAs, we conclude that the use of low sulphur fuel is expected to increase the transport prices particularly on the origin–destination relations with a medium or long short sea section. The paper also presents the results of a survey among leading short sea operators in the ECAs in view of providing more insight on expected modal shifts and price elasticity in the short sea market.