Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: keys

Sortuj według:

Ogranicz wyniki do:

Labels on coloured tactile maps (typhlomaps) – the Polish experiences

Olczyk M.

Polish Cartographical Review

2018

Vol. 50, No. 4

197--209

The author presents the problems associated with geographical name conventions and labels on coloured tactile maps in atlas-type publications for the blind and visually impaired, based on the author’s many years of experience. The detailed description of the ‘keys’ system and Braille ‘abbreviations’ which Polish cartography uses in this type of works shows the benefits of using the system in the editing of map series. A framework of logical and intuitive ‘abbreviations’ presents many possibilities and makes maps easier to read. The system for connecting names of a particular ‘family’ of terms by using a two-letter abbreviation preceded by a unique ‘key’ should be a fundamental principle for creating sets of Braille ‘abbreviations’ for use in a given work. The author also highlights the need to use exonyms, since Braille’s basic alphabet has none of the diacritic characters which typify various languages, which hinders the correct transcription of certain names. The proposed system for constructing ‘abbreviations’ and ‘keys’ may also be used effectively in individual town plans and maps to improve the communication of information. The comprehensive structure of this system also makes it easier to search through indexes of ‘abbreviations’ and their explanations. All the described elements have an impact in raising the practical value of tactile maps.

Counter-Free Keys and Functional Dependencies in Higher-Order Datamodels

Sali A., Schewe K-D.

Fundamenta Informaticae

2006

Vol. 70, nr 3

277-301

We investigate functional dependencies (FDs) in the presence of several constructors for complex values. These constructors are the tuple constructor, list-, set- and multiset-constructors, an optionality constructor, and a disjoint union constructor. The disjoint union constructor implies restructuring rules, which complicate the theory. In particular, they do not permit a straightforward axiomatisation of the class of all FDs without a detour via weak functional dependencies (wFDs), i.e. disjunctions of functional dependencies, and even the axiomatisation of wFDs is not yet completely solved. Therefore, we look at the restricted class of counter-free functional dependencies (cfFDs). That is, we ignore subattributes that only refer to counting the number of elements in sets or multisets or distinguish only between empty or non-empty sets. We present a finite axiomatisation for the class of cfFDs. Furthermore, we study keys ignoring again the counting subattributes. We show that such keys are equivalent with certain ideals called HL-ideals. Based on that we introduce an ordering between key sets, and investigate systems of minimal keys. We give a sufficient condition for a Sperner family of HL-ideals being a system of minimal keys, and determine lower and upper bounds for the size of the smallest Armstrong-instance.