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2 TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2 2014

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PER Estimation of AIS in Inland Rivers based on Three Dimensional Ray Tracking

Ma F., Chu X. M., Liu C. G.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2014

Vol. 8, no. 1

89--94

The Automatic Identification System (AIS) is an important maritime safety device, which is populous in inland rivers. Compared with that in open sea, the Package Error Rate (PER) of AIS in inland river has increased sharply due to its complex environment. With the help of hardware in loop simulation, it is possible to make statistical calculation on the PER under a given field strength and describe the data by quadratic rational fraction. Meanwhile, in the three dimensional software environments, the signal field strength is able to be calculated by the ray tracking method, which exhausts all the possible propagation paths, including direct way, reflection, diffractions, and the other medium attenuation matters. Beyond that, in the model, the propagation geography information in inland rivers is required to be simplified in some way, or the computation of the ray tracking is too hard to get. The paper set the Changjiang Wuhan channel as the field testing region, and all the deviations are less than 5% in sunny weather, which proves the method accurate and effective.

Determination of Parameters to Model Seafarers’ Supply in Latvia

Gailitis R., Fjodorova A.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2014

Vol. 8, no. 2

245--252

Shortage of seafarers is important topic as maritime industry plays a key role for economy of the European Union. According to the latest assessment of economic value of shipping industry in 2012, the EU shipping industry is estimated to have directly contributed €56 billion to GDP, employed 590,000 people, and generated tax revenues of €6 billion. During recent years increasing attention is paid to the education and training of seafarers as the seafarers and their knowledge are essential to sustainable development of the maritime cluster, as indicated in the maritime strategy of European Union. Indicative estimates suggest there were almost 38,000 students/cadets in maritime academy – type training across the EU and Norway in 2012, a 11% increase from 2004. Understanding of current trends in the pool of seafarers is prerequisite for successful implementation of the strategy. Main obstacle for assessment of effectiveness is lack of possibilities to monitor contribution from maritime education institutions to current state of European seafarers’ pool. The aim of this article is to show parameters which should be taken into account to model seafarers’ supply in future. The parameters are discussed on the basis of information from the Seamen Registry of Maritime Administration of Latvia.