  Logistics networks arise whenever there is a transfer of material substance
or objects (such as checked baggage on international flights) as well as
energy, information, or finance through links (channels). A general concept of
logistics network is suggested and motivated for modeling a service of any kind
supplied through links between the nodes of the network. The efficiency of a
single link is defined to be the ratio of the volume of useful service at the
output node to the volume of expended service at the input node of the link
(for a specific period of time). Similarly, the efficiency of a chain is the
ratio of the volume of service at the output to the volume of service at the
input of the chain. The overall efficiency of the chain is calculated as the
product of the efficiencies of its links; the more efficiency of the chain, the
less are the losses in the chain. This paper introduces the notion of
inadequacy of service in such a way that the overall inadequacy of a chain is
equal to the sum of the inadequacies of its links. So the efficiencies are
being multiplied, whereas the inadequacies are being added. Thus, the
antagonistic pair (efficiency, inadequacy) appears to be analogous to the pair
(reliability, entropy) in communication theory. Various possible
interpretations of the proposed logistic model are presented: energy, material,
information and financial networks. Four algorithms are provided for logistics
chain search: two algorithms for finding the most effective chain from a
specified origin to a specified destination, and two algorithms for finding the
guaranteed minimum level of service between any pair of unspecified nodes in a
given network. An example is shown as to how one of the algorithms finds the
most efficient energy chain from the electrical substation to a specified user
in a concrete energy network.
