An integrated framework for embedding large-scale dynamic traffic assignment models in advanced traveler information systems

In recent years, increasing attention has been drawn to the development of various applications of intelligent transportation systems (ITS), which are credited with the amelioration of traffic conditions in urban and regional environments. Advanced traveler information systems (ATIS) constitute an important element of ITS by providing potential travelers with information on the network's current performance both en-route and pre-trip. In order to tackle the complexity of such systems, derived from the difficulty of providing real-time estimations of current as well as forecasts of future traffic conditions, a series of models and algorithms have been initiated. This paper proposes the development of an integrated framework for real-time ATIS and presents its application on a large-scale network, that of Thessaloniki, Greece, concluding with a discussion on development and implementation challenges as well as on the advantages and limitations of such an effort.     

Competitiveness between short sea shipping and road freight transport in mainland port connections; the case of two Greek ports

While road freight transport is essential to any modern economy, short sea shipping (SSS) offers a competitive alternative mode of freight transport in terms of private and social costs, when applied in the connection of mainland ports. This mainly stems from the fact that within the context of the latter costs, accidents and environmental impacts in many road links constitute undesirable externalities with which road freight transport is heavily burdened. This paper compares the aforementioned economics of road and sea transport with reference to the connection of the port of Patra (the main western freight gate of Greece) with West Attica (the biggest Greek industrial centre), aiming at providing a viable solution towards the promotion of SSS in the transport chain between mainland ports.     

Can clusters be bi-polar? Exploring the case of the Piraeus port–maritime cluster

ABSTRACT

Further to being Greece’s biggest port, Piraeus has been a traditional pole of attraction for a plethora of organisations, companies, and institutions engaged in port- and shipping-related activities. Regional development literature has already indicated that the benefits deriving from adjacency and agglomeration economies are maximised when individual entities are organised in forming business clusters. Therefore, the paper critically addresses the existence of theoretical preconditions to a competitive port–maritime cluster formulation in wider Piraeus area. Based on a thorough review of cluster theory, the basic characteristics of clusters are identified to provide the analytical tools for examining the geographical concentration and economic specialisation in Piraeus. Field research in the form of in-depth interviews with leading shipping- and port-related business representatives and institutional bodies and the analysis of qualitative and quantitative data collected revealed that necessary preconditions for successful cluster formulation are met despite the inexistence of a formally recognised cluster. Two distinct poles of economic activity (shipping and port related) are recognised, demonstrating differentiated clustering behaviours and patterns of interaction with other players. The paper concludes with proposals deriving from this dual cluster structure and governance and the need for innovative, differentiated strategies.     

Sea-going labour and Greek owned fleet: a major aspect of fleet competitiveness

This analysis aims to examine the current picture of maritime manpower in the Greek registered and owned fleet, as it has been formed during the post-war years. This objective entails the analysis of the current supply and demand for seafarers, the estimation of any shortfalls and their confrontation. Moreover, this study further investigates the contributory factors of the present employment trends, which simultaneously constitute special problems of the sea manpower of the Greek owned fleet and attempt some recommendations. In the context of the above mentioned objective, this analysis emphasizes issues such as recruitment, marine education and wastage. Furthermore, special consideration is given to the significance of labour costs for the development of the Greek owned fleet, particularly to subjects such as the various ways of reducing manning costs and their repercussions on the employment of Greek seamen. Finally, this analysis examines the trends of the state shipping policy concerning labour issues and proceeds to some recommendations.     

The Force-Angle Measure of Tipover Stability Margin for Mobile Manipulators

Mobile manipulators operating in field environments will be required to apply large forces, or manipulate large loads, and to perform such tasks on uneven terrain which may cause the system to approach, or reach, a dangerous tipover instability. To avoid tipover in an automatic system, or to provide a human operator with an indication of proximity to tipover, it is necessary to define a measure of available stability margin. This work presents a new tipover stability measure (the Force-Angle stability measure) which has a simple geometric interpretation, is easily computed, and is sensitive to changes in Center of Mass height. The proposed metric is applicable to systems subject to inertial and external forces, operating over even or uneven terrains. Requirements for computation and implementation of the measure are described, and several different categories of application of the measure are presented along with useful normalizations. Performance of the Force-Angle measure is demonstrated and compared with that of other stability margin measures using a forestry vehicle simulation. Results show the importance of considering both center-of-mass height and system heaviness, and confirm the effectiveness of the Force-Angle measure in monitoring the tipover stability margin.     

Multi-objective optimization of oil tanker design

Parametric optimization was applied to a double-hull AFRAMAX tanker design in order to reduce oil-outflow probability and increase cargo carrying capacity, and the results are presented here. A multi-criteria optimization procedure was set up in modeFrontier ^® using the cargo volume, the mean oil-outflow parameter and the steel weight of the cargo block as the objective functions. Calculations are based on a parametric geometric model of the ship created in NAPA ^®, and on a structural model created in POSEIDON ^®. Integration of the above software packages leads to an automated optimization procedure that provides improved feedback to the designer regarding the trade-off between the various design parameters and optimization criteria involved. The results obtained suggest notable improvements in transport capacity and oil-outflow performance for known, well-established yard designs. The presented work derives from a joint industrial project between Germanischer Lloyd (GL) and the Ship Design Laboratory of the National Technical University of Athens (NTUA-SDL), which continues the work done and coordinated by NTUA-SDL within the SAFEDOR project on the same subject.     

Maritime policy making for flag states: Forecasting safety/detention performance with the use of time series analysis

In this paper time series univariate forecast methods and analysis of time series is used in an innovative way, with the intention of assisting the flag state administrators to map and predefine their shipping quality policy. In general, given the number of ships detained by Port State Control (PSC) and corresponding inspections of the flag fleet for the same period of time, one is able to forecast the Paris Memorandum of Understanding (Paris MoU) excess factor of any flag state for a selected time window. Thus, depending on the goals of each flag state administration, one can judge their feasibility (e.g. remain in the Paris MOU White List or achieve an excess factor of —1 etc) and determine whether to enhance the safety measures or not. The method is first developed and discussed on an abstract basis to set the theoretical background, a combination of time series analysis and practical engineering philosophy. Then the study focuses upon the Cyprus Flag figures in Paris MOU ports, only to demonstrate its effectiveness but can in any case be applied upon any given flag. The application of the method suggested, combined with expert judgment, could result in a significant improvement of the flag quality.     

Integrating banks’ decision on financing dry bulk shipping: a multivariable approach

ABSTRACT

Shipping is characterized by extreme changes in revenues, operating expenses and asset values, making shipping banks’ final decision for financing shipping market considerably harder. This paper develops a practical decision tool based on the estimation of the credibility factor in the decision-making process, each bank’s policy, and the most significant variables arising from both its operating environment and the dry bulk market. Revealed relationships between bank’s internal environment, its own policy, and dry-bulk shipping market conditions through GDP growth of China constitute a newly presented decision framework in shipping finance. The values of credibility factor implicate either an aggressive or passive defensive strategy taking into account the GDP China changes: Consistent with the economic growth of China, a bank’s holds an aggressive policy if the credibility coefficient is about one. On the other hand, the model predicts that a less aggressive policy in combination with the increase of China’s GDP would drive to the decrease of bank’s loan grants.     

Modelling,simulation and evaluation of ground vibration caused by rail vehicles*

ABSTRACT

There is a great need to develop rail networks over long distances and within cities as more sustainable transport options. However, noise and vibration are seen as a negative environmental consequence. Compared with airborne noise, the related problem of ground vibration is much more complex. The properties of the ground vary significantly from one location to another. There is no common assessment criterion or measurement quantity and no equivalent to the noise maps. Ground-borne vibration is transmitted into buildings and perceived either as feelable whole-body vibration or as low frequency noise; it can also affect sensitive equipment but it is generally at a level that is too low to cause structural or cosmetic damage to buildings. A review is given of evaluation criteria for both feelable vibration and ground-borne noise, empirical and numerical prediction methods, the main vehicle and track parameters that can affect the vibration levels and a range of possible mitigation methods.     

Sea-going labour and Greek owned fleet: a major aspect of fleet competitiveness

This analysis aims to examine the current picture of maritime manpower in the Greek registered and owned fleet, as it has been formed during the post-war years. This objective entails the analysis of the current supply and demand for seafarers, the estimation of any shortfalls and their confrontation. Moreover, this study further investigates the contributory factors of the present employment trends, which simultaneously constitute special problems of the sea manpower of the Greek owned fleet and attempt some recommendations. In the context of the above mentioned objective, this analysis emphasizes issues such as recruitment, marine education and wastage. Furthermore, special consideration is given to the significance of labour costs for the development of the Greek owned fleet, particularly to subjects such as the various ways of reducing manning costs and their repercussions on the employment of Greek seamen. Finally, this analysis examines the trends of the state shipping policy concerning labour issues and proceeds to some recommendations.