Simple 2^f-Color Choice Dictionaries

A c-color choice dictionary of size n in N is a fundamental data structure in the development of space-efficient algorithms that stores the colors of n elements and that supports operations to get and change the color of an element as well as an operation choice that returns an arbitrary element of that color. For an integer f>0 and a constant c=2^f, we present a word-RAM algorithm for a c-color choice dictionary of size n that supports all operations above in constant time and uses only nf+1 bits, which is optimal if all operations have to run in o(n/w) time where w is the word size. In addition, we extend our choice dictionary by an operation union without using more space

Igbo dialects and the citation-form: the possibility of a standard Igbo dictionary

It is the norm in lexicography to have dictionary headwords in the standard variety of the language. But up to date, no Igbo dictionary exists in this variety. Most Igbo lexicographers have adopted the dialectal or multidialectal approach in their choice of a citation-form. The multiplicity of Igbo dialects accounts for this situation. This paper examines both sound and lexical variations in the language; describes the lexicographic problems of choice and arrangement of headwords, and discusses the suitability of the Igbo dictionary as a tool for standardizing the language. Two major sources of data were employed: the modified Ibadan 400 wordlist of basic items - used for a survey of the seven dialect zones identified by Manfredi (1989), and the dictionaries of Welmers and Welmers (1968), Williamson (1972), Igwe (1999) and Echeruo (2001). The paper demonstrated that sound and lexical variants in Igbo can be harnessed by Igbo lexicographers to produce an Igbo dictionary in the standard variety. Considering the optimal benefits derivable from a standard dictionary, the following suggestions for future Igbo lexicographers are proffered: words from different dialects of the language should be included in the dictionary; the standard forms be selected and consistently entered as headwords. Words with sound variation should be treated as sub-entries and lexical variants be cited as main-entries in their right alphabetical positions. The paper argued that, for the Igbo dictionary to fulfil its indispensable role as a language standardizing tool, the production of a Standard Igbo dictionary is imperative in Igbo lexicography and Igbo language studies

Dictionary learning with large step gradient descent for sparse representations

This is the accepted version of an article published in Lecture Notes in Computer Science Volume 7191, 2012, pp 231-238. The final publication is available at link.springer.com http://www.springerlink.com/content/l1k4514765283618