Parcel size distribution

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Parcel Size Distribution ( PSD , German about charging size distribution ) is a characteristic value for batches of cargo of various transported by ship goods. It is used in maritime economics to represent the range and frequency of certain cargo sizes of various goods in sea transport.

details

Different goods are shipped by sea in different cargo sizes and different types of ship; the cargo can fill an entire ship or be transported as a partial load. Depending on the type of cargo, there is a certain distribution of frequencies of shipments over a certain bandwidth for each good, according to which the respective good can be characterized. This distribution can be represented in a PSD function. Put simply, the load can be assigned to one or more typical shipping sizes and types (for example on a tramp or on a liner) using its PSD. In addition, the PSD can be used to determine whether types of cargo are mainly shipped as batches that fill an entire ship, or whether they are transported as part loads.

Iron ore, for example, has a PSD, according to which only low frequencies are reduced to the smallest (0-40,000 tons), smaller (40,000-60,000 tons), medium (60,000-80,000 tons) and large (80,000-100,000 tons), but very high frequencies to the greatest Loads of loads (over 100,000 tons) fall. From this, on the one hand, the almost exclusive transport with bulk carriers and, in this segment, the transport with very large ship units. In contrast to this, the PSD of other bulk goods concentrates, for example, on comparatively smaller loads that are transported on smaller bulk carriers or multi-purpose ships, while that of general cargo normally focuses on the smallest segment and types of ship , such as container ships or RoRo cargo ships (there mostly as part loads).

literature

  • Martin Stopford: Maritime Economics . Routledge, Oxon, New York 1997, ISBN 0-415-15310-7 .
  • Yuen Ha Venus Lun, Kee-hung Lai, Tai Chiu Edwin Cheng: Shipping and Logistics Management . 1st edition. Springer, Berlin 2010, ISBN 978-1-84882-996-1 .