4 research outputs found
Variable-to-Fixed Length Homophonic Coding Suitable for Asymmetric Channel Coding
In communication through asymmetric channels the capacity-achieving input
distribution is not uniform in general. Homophonic coding is a framework to
invertibly convert a (usually uniform) message into a sequence with some target
distribution, and is a promising candidate to generate codewords with the
nonuniform target distribution for asymmetric channels. In particular, a
Variable-to-Fixed length (VF) homophonic code can be used as a suitable
component for channel codes to avoid decoding error propagation. However, the
existing VF homophonic code requires the knowledge of the maximum relative gap
of probabilities between two adjacent sequences beforehand, which is an
unrealistic assumption for long block codes. In this paper we propose a new VF
homophonic code without such a requirement by allowing one-symbol decoding
delay. We evaluate this code theoretically and experimentally to verify its
asymptotic optimality.Comment: Full version of the paper to appear in 2017 IEEE International
Symposium on Information Theory (ISIT2017
Maritime expressions:a corpus based exploration of maritime metaphors
This study uses a purpose-built corpus to explore the linguistic legacy of Britain’s maritime history found in the form of hundreds of specialised ‘Maritime Expressions’ (MEs), such as TAKEN ABACK, ANCHOR and ALOOF, that permeate modern English. Selecting just those expressions commencing with ’A’, it analyses 61 MEs in detail and describes the processes by which these technical expressions, from a highly specialised occupational discourse community, have made their way into modern English. The Maritime Text Corpus (MTC) comprises 8.8 million words, encompassing a range of text types and registers, selected to provide a cross-section of ‘maritime’ writing. It is analysed using WordSmith analytical software (Scott, 2010), with the 100 million-word British National Corpus (BNC) as a reference corpus. Using the MTC, a list of keywords of specific salience within the maritime discourse has been compiled and, using frequency data, concordances and collocations, these MEs are described in detail and their use and form in the MTC and the BNC is compared. The study examines the transformation from ME to figurative use in the general discourse, in terms of form and metaphoricity. MEs are classified according to their metaphorical strength and their transference from maritime usage into new registers and domains such as those of business, politics, sports and reportage etc. A revised model of metaphoricity is developed and a new category of figurative expression, the ‘resonator’, is proposed. Additionally, developing the work of Lakov and Johnson, Kovesces and others on Conceptual Metaphor Theory (CMT), a number of Maritime Conceptual Metaphors are identified and their cultural significance is discussed