horizon: Create a function that computes linguistic horizons

In lfl: Linguistic Fuzzy Logic

Create a function that computes linguistic horizons

Description

Based on given context and atomic expression, this function returns a function that computes a linguistic horizon, i.e. a triangular function representing basic limits of what humans treat as "small", "medium", "big" etc. within given context. Linguistic horizon stands as a base for creation of linguistic expressions. A linguistic expression is created by applying a hedge() on horizon. (Atomic linguistic expression is created from horizon by applying an empty (-) hedge).

Usage

horizon(
  context,
  atomic = c("sm", "me", "bi", "lm", "um", "ze", "neg.sm", "neg.me", "neg.bi",
    "neg.lm", "neg.um")
)

Arguments

context	A context of linguistic expressions (see ctx3(), ctx5(), ctx3bilat() or ctx5bilat())
atomic	An atomic expression whose horizon we would like to obtain

Details

The values of the atomic parameter have the following meaning (in ascending order):

• neg.bi: big negative (far from zero)

• neg.um: upper medium negative (between medium negative and big negative)

• neg.me: medium negative

• neg.lm: lower medium negative (between medium negative and small negative)

• neg.sm: small negative (close to zero)

• ze: zero

• sm: small

• lm: lower medium

• me: medium

• um: upper medium

• bi: big

Based on the context type, the following atomic expressions are allowed:

• ctx3() (trichotomy): small, medium, big;

• ctx5() (pentachotomy): small, lower medium, medium, upper medium, big;

• ctx3bilat() (bilateral trichotomy): negative big, negative medium, negative small, zero, small, medium, big;

• ctx5bilat() (bilateral pentachotomy): negative big, negative medium, negative small, zero, small, medium, big.

This function is quite low-level. Perhaps a more convenient way to create linguistic expressions is to use the lingexpr() function.

Value

A function of single argument that must be a numeric vector

Author(s)

Michal Burda

See Also

ctx3(), ctx5(), ctx3bilat(), ctx5bilat(), hedge(), fcut(), lcut()

Examples

    plot(horizon(ctx3(), 'sm'), from=-1, to=2)
    plot(horizon(ctx3(), 'me'), from=-1, to=2)
    plot(horizon(ctx3(), 'bi'), from=-1, to=2)

    a <- horizon(ctx3(), 'sm')
    plot(a)
    h <- hedge('ve')
    plot(h)
    verySmall <- function(x) h(a(x))
    plot(verySmall)

lfl documentation built on Sept. 8, 2022, 5:08 p.m.