Microeconomic determinants of dry bulk shipping freight rates and contract times

While the literature has established macroeconomic determinants of shipping freight (charter) rates, there has been no systematic investigation of the microeconomic determinants of shipping freight rates. Therefore, the purpose of this paper is to investigate microeconomic determinants of freight rates in the dry bulk shipping market, using a large sample of individual dry bulk charter contracts from January 2003 to July 2009. Differences in freight rates across major dry bulk shipping routes, the geographical distribution of shipping activities around the world, and the duration of the laycan period of shipping contracts are also investigated. Estimated results suggest that the laycan period and dry bulk freight rates are interrelated and determined simultaneously. Furthermore, vessel deadweight, age and voyage routes are important determinants of dry bulk shipping freight rates, while determinants of the laycan period of chartered vessels include vessel age, freight rate level, and freight rate volatility.     

Household travel attributes transferability analysis: application of a hierarchical rule based approach

This paper presents a system of hierarchical rule-based models of trip generation and modal split. Travel attributes, like trip counts for different transportation modes and commute distance, are among the modeled variables. The proposed framework could be considered as an alternative for several modules of the traditional travel demand modeling approach, while providing travel attributes at the highly disaggregate level that can be also used in activity-based micro-simulation modeling systems. Nonetheless, the modeling framework of this study is not considered as a substitute for activity-based models. The explanatory variables set ranges from socio-economic and demographic attributes of the household to the built environment characteristics of the household residential location. Another important contribution of the study is a framework in which travel attributes are modeled in conjunction with each other and the interdependencies among them are postulated through a hierarchical system of models. All the models are developed using rule-based decision tree method. Moreover, the models developed in this study present a useful improvement in increasing the practicality and accuracy of the rule-based travel data simulation models.