Ports as elements in value-driven chain systems: the new paradigm

This paper argues that, with the rapid and pervasive restructuring of supply chains and of the logistics pathways in which ports are embedded, existing paradigms no longer offer adequate insights into the functions of ports or port authorities. Rather, ports must now be seen as elements in value-driven chain systems or in value chain constellations. They deliver value to shippers and to third party service providers; customer segmentation and targeting is on the basis of a clearly specified value proposition; and the port captures value for itself and for the chain in which it is embedded. The role of ports and port authorities, and the way in which they position themselves in the new business environments beyond 2001 must be defined within a paradigm of ports as elements in value-driven chain systems, not simply as places with particular, if complex, functions.     

Urban travel demand: The impact of Box-Cox transformations with nonspherical residual errors

We develop an algorithm for solving regression models with Box-Cox transformations on both the dependent and independent variables, while simultaneously taking into account corrections for serial correlation of several orders and for heteroscedasticity. The latter correction is of a general form which contains as special cases most specifications of heteroscedasticity found in practice. We apply the procedure to three urban travel demand functions, two of which are currently used in their linear form by the Montreal Transit Authority, and analyze more than 100 specifications. Our results show that taking into account nonsphericalness of the residuals has a major impact on model parameter estimates, notably on those which determine the functional form of the model, and that, conversely, modifications of the functional form have strong implications for both the structure of autocorrelation and the importance of heteroscedasticity; moreover, we find interactions between autocorrelation and heteroscedasticity structures. We introduce a special measure of elasticity for variables which contain zero observations, particularly dummy variables. Moreover, we find that elasticities of demand and implicit values of time depend to a large extent on the stochastic specification of the model.     

Bottom slamming on heaving point absorber wave energy devices

Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise angles of 30° and 45°, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45° cone is approximately 2, whereas the power absorption is only 4–8% higher for the 45° cone. This work illustrates the need to include slamming considerations aside from power absorption criteria in the buoy shape design process and the control strategy.     

Part 2. Beyond single-outcome models: Decompositions of aggregate and disaggregate road safety risk

The second part of the state-of-the-art focuses on the development of the founders' double streams explaining single-outcome indicators (probability of accidents and fatalities, respectively) by fixed form regression, as outlined in the Part 1. Following Page (1997, pp. 67–122, 2001) and others, we use as turning point of the evolution of both aggregate and discrete approaches the DRAG-1 model of 1984, itself based on aggregate data, which introduced four key innovations in principle applicable to both streams.     

Impacts of the 2004 Tsunami on Surin Marine National Park,Thailand

The impacts of the tsunami in 2004 on the reefs in Surin Marine National Park, Thailand, varied with the location and exposure of the reefs. Channel areas between islands were severely damaged. Areas with steep reef slopes were damaged by sand slides or coral collapse more than areas with low slopes. Massive, sub-massive, and encrusting corals were more resistant and resilient to the direct impact of the tsunami than branching, tabulate, and foliose life forms whereas the latter were more tolerant of temporary coverage by sand. Sub-massive corals were the most tolerant overall and survived sand coverage, breakage, and overturning. Live coral cover measured three months after the tsunami was significantly greater than immediately post-tsunami as broken, moved, or sand-covered corals, recorded as impacted in the initial survey, had survived and were regenerating. Low turbidity, lack of pollution, and mild currents possibly contributed to rapid recovery and limited long-term effects of the tsunami. Impact assessment shortly after a major disturbance may give an initial measure of damage but subsequent surveys must be undertaken to identify long-term effects. Understanding patterns of reef damage can help to formulate reef zoning and protection strategies in response to catastrophic events, but also in advance of such events to improve likely resilience of the marine park to disturbance.     

Train-to-wayside wireless communication in tunnel using ultra-wide-band and time reversal

The capabilities of ultra-wide-band (UWB) technology make it a viable candidate for fourth generation wireless communication. This paper proposes the use of UWB radio technology and time-reversal (TR) technique for underground train-to-wayside communication systems. UWB technology has the potential to offer simultaneous ground-to-train communication, train location and obstacle detection in front of the trains. Time-reversal channel prefiltering facilitates signal detection and helps reducing interference. Thus, UWB–TR combination provides a challenging, economically sensible, as well as technically effective alternative solution to existing signaling technologies used in urban transport systems. This paper concentrates on the communication function and reports simulation and measurement performance evaluation of such combinations, respectively in a deterministic tunnel channel model and in real tunnel environments. A new approach is also proposed to ensure multiple access (MA) communication using modified-orthogonal waveforms.     

Spatial allocation on a network with congestion

This article formalizes the land use design problem as a discrete-convex programming problem integrating within a quadratic assignment framework a realistic representation of transportation behavior (automobile congestion and variable demand for travel) as modelled by a combined trip distribution trip assignment model. Hill-climbing algorithms are proposed to solve the resulting optimization problem. Their performance is compared and evaluated on a set of test problems.     

提高文化用纸中填料含量的新技术

一种新技术，该技术依靠一种独特的方法实现填料预絮凝，可使造纸厂在不影响质量的前提下提高填料含量     

Modelling propeller and rudder induced forces acting on deep drafted vessels in muddy navigation areas

To assess the navigability of deep drafted vessels in muddy navigation areas a mathematical model has been built that takes into account the characteristics of the mud layer. This was achieved with the introduction of a fluidization parameter which determines the corresponding hydrodynamically equivalent depth above a solid bottom. As a result, the under keel clearance dependency of a given mathematical manoeuvring model can be reformulated in such way that the effect of any realistic muddy condition is included. In this article the modelling of the propeller and rudder induced forces and the implementation possibilities of the model will be discussed. It is concluded that the mathematical model, initially formulated for a 6,000 TEU container carrier, provides reliable predictions of the behaviour of larger container carriers and even fuller deep drafted ships.