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| author | Juan Marin Noguera <juan@mnpi.eu> | 2022-12-11 18:57:10 +0100 |
|---|---|---|
| committer | Juan Marin Noguera <juan@mnpi.eu> | 2022-12-11 18:57:10 +0100 |
| commit | 75949f710807d090d725c6d99787773316439ce8 (patch) | |
| tree | dfa2258c701c78959d255c8ffa700455b756248e /dsi | |
| parent | 448479279f4fa7fd31b6d688747338524d83b5d7 (diff) | |
DSI tema 7 lógica borrosa
Diffstat (limited to 'dsi')
| -rw-r--r-- | dsi/n.lyx | 14 | ||||
| -rw-r--r-- | dsi/n7.lyx | 1029 |
2 files changed, 1043 insertions, 0 deletions
@@ -330,5 +330,19 @@ filename "n6.lyx" \end_layout +\begin_layout Chapter +Lógica borrosa +\end_layout + +\begin_layout Standard +\begin_inset CommandInset include +LatexCommand input +filename "n7.lyx" + +\end_inset + + +\end_layout + \end_body \end_document diff --git a/dsi/n7.lyx b/dsi/n7.lyx new file mode 100644 index 0000000..f42f65f --- /dev/null +++ b/dsi/n7.lyx @@ -0,0 +1,1029 @@ +#LyX 2.3 created this file. For more info see http://www.lyx.org/ +\lyxformat 544 +\begin_document +\begin_header +\save_transient_properties true +\origin unavailable +\textclass book +\begin_preamble +\input{../defs} +\end_preamble +\use_default_options true +\maintain_unincluded_children false +\language spanish +\language_package default +\inputencoding auto +\fontencoding global +\font_roman "default" "default" +\font_sans "default" "default" +\font_typewriter "default" "default" +\font_math "auto" "auto" +\font_default_family default +\use_non_tex_fonts false +\font_sc false +\font_osf false +\font_sf_scale 100 100 +\font_tt_scale 100 100 +\use_microtype false +\use_dash_ligatures true +\graphics default +\default_output_format default +\output_sync 0 +\bibtex_command default +\index_command default +\paperfontsize default +\spacing single +\use_hyperref false +\papersize default +\use_geometry false +\use_package amsmath 1 +\use_package amssymb 1 +\use_package cancel 1 +\use_package esint 1 +\use_package mathdots 1 +\use_package mathtools 1 +\use_package mhchem 1 +\use_package stackrel 1 +\use_package stmaryrd 1 +\use_package undertilde 1 +\cite_engine basic +\cite_engine_type default +\biblio_style plain +\use_bibtopic false +\use_indices false +\paperorientation portrait +\suppress_date false +\justification true +\use_refstyle 1 +\use_minted 0 +\index Index +\shortcut idx +\color #008000 +\end_index +\secnumdepth 3 +\tocdepth 3 +\paragraph_separation indent +\paragraph_indentation default +\is_math_indent 0 +\math_numbering_side default +\quotes_style french +\dynamic_quotes 0 +\papercolumns 1 +\papersides 1 +\paperpagestyle default +\tracking_changes false +\output_changes false +\html_math_output 0 +\html_css_as_file 0 +\html_be_strict false +\end_header + +\begin_body + +\begin_layout Standard +Una +\series bold +variable lingüística +\series default + es una tupla +\begin_inset Formula $V=(N,U,T,G,M)$ +\end_inset + + donde +\begin_inset Formula $N$ +\end_inset + + es el +\series bold +nombre +\series default + de la variable, +\begin_inset Formula $U$ +\end_inset + + es el +\series bold +dominio +\series default + de valores de la variable, +\begin_inset Formula $T$ +\end_inset + + es un alfabeto cuyos símbolos se llaman +\series bold +etiquetas lingüísticas +\series default +, +\begin_inset Formula $G$ +\end_inset + + es una gramática con alfabeto +\begin_inset Formula $T$ +\end_inset + + y +\begin_inset Formula $M:L(G)\to(U\to[0,1])$ +\end_inset + + es una +\series bold +regla semántica +\series default +. + Llamamos +\series bold +término lingüístico +\series default + de +\begin_inset Formula $V$ +\end_inset + + a un elemento de +\begin_inset Formula $L(G)$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Estas variables permiten describir términos del lenguaje natural en términos + matemáticos precisos. + En general +\begin_inset Formula $G$ +\end_inset + + es de la forma +\begin_inset Formula +\[ +S\to P\mid H\,S\mid(S\,\text{and}\,S)\mid(S\,\text{or}\,S)\mid(\text{not}\,S), +\] + +\end_inset + +donde +\begin_inset Formula $P$ +\end_inset + + es un conjunto finito de +\series bold +términos primarios +\series default + o +\series bold +etiquetas lingüísticas +\series default + (bajo, alto, medio, etc.), +\begin_inset Formula $H$ +\end_inset + + uno de +\series bold +modificadores lingüísticos +\series default + o +\series bold +\emph on +\lang english +hedges +\series default +\emph default +\lang spanish +, y llamamos +\series bold +conectores lógicos +\series default + a +\begin_inset Formula $\text{and}$ +\end_inset + +, +\begin_inset Formula $\text{or}$ +\end_inset + + y +\begin_inset Formula $\text{not}$ +\end_inset + +. + Un +\series bold +término atómico +\series default + es un término primario, un +\emph on +\lang english +hedge +\emph default +\lang spanish + o un conector lógico. + Cada término primario +\begin_inset Formula $p$ +\end_inset + + lleva asociado un +\begin_inset Formula $C_{p}:U\to[0,1]$ +\end_inset + + y cada modificador +\begin_inset Formula $h$ +\end_inset + + una transformación +\begin_inset Formula $T_{h}:(U\to[0,1])\to(U\to[0,1])$ +\end_inset + +, y para +\begin_inset Formula $p\in P$ +\end_inset + +, +\begin_inset Formula $h\in H$ +\end_inset + + y +\begin_inset Formula $r,s\in L(G)$ +\end_inset + +, +\begin_inset Formula +\begin{align*} +M(p) & \coloneqq C_{p}, & M(h\,r) & \coloneqq T_{h}(M(r)), & M(\text{not}\,r) & \coloneqq N(M(r)),\\ +M(r\,\text{and}\,s) & \coloneqq M(r)*M(s), & M(r\text{ or }s) & \coloneqq M(r)\oplus M(s), +\end{align*} + +\end_inset + +donde +\begin_inset Formula $N$ +\end_inset + + es la negación, +\begin_inset Formula $*$ +\end_inset + + la t-norma y +\begin_inset Formula $\oplus$ +\end_inset + + la s-norma. +\end_layout + +\begin_layout Standard +Tipos de +\emph on +\lang english +hedges +\emph default +\lang spanish +: +\end_layout + +\begin_layout Itemize + +\series bold +De concentración: +\series default + +\begin_inset Formula $T_{h}(S)(x)\coloneqq S(x)^{p}$ +\end_inset + + para cierto +\begin_inset Formula $p>1$ +\end_inset + +. + +\begin_inset Formula +\begin{align*} +T_{\text{muy}}(S)(x) & \coloneqq S(x)^{2}, & T_{\text{más}}(S)(x) & \coloneqq S(x)^{\frac{5}{4}}. +\end{align*} + +\end_inset + + +\end_layout + +\begin_layout Itemize + +\series bold +De dilatación: +\series default + +\begin_inset Formula $T_{h}(S)(x)\coloneqq S(x)^{p}$ +\end_inset + + para cierto +\begin_inset Formula $p\in[0,1]$ +\end_inset + +. + +\begin_inset Formula +\begin{align*} +T_{\text{más o menos}}(S)(x) & \coloneqq\sqrt{S(x)}, & T_{\text{poco}}(S)(x) & \coloneqq S(x)^{\frac{3}{4}}. +\end{align*} + +\end_inset + + +\end_layout + +\begin_layout Itemize + +\series bold +De intensificación: +\series default + Para cada +\begin_inset Formula $x$ +\end_inset + +, +\begin_inset Formula $S(x)$ +\end_inset + + está entre +\begin_inset Formula $T_{h}(S)(x)$ +\end_inset + + y +\begin_inset Formula $\frac{1}{2}$ +\end_inset + +. +\begin_inset Formula +\[ +T_{\text{especialmente}}(S)(x)\coloneqq T_{\text{bastante}}(S)(x)\coloneqq\begin{cases} +2S(x)^{2}, & x\in[0,\frac{1}{2}];\\ +1-2(1-S(x))^{2}, & x\in[\frac{1}{2},1]. +\end{cases} +\] + +\end_inset + + +\end_layout + +\begin_layout Itemize + +\series bold +De difuminación: +\series default + Para cada +\begin_inset Formula $x$ +\end_inset + +, +\begin_inset Formula $T_{h}(S)(x)$ +\end_inset + + está entre +\begin_inset Formula $S(x)$ +\end_inset + + y +\begin_inset Formula $\frac{1}{2}$ +\end_inset + +. +\begin_inset Formula +\[ +T_{\text{cerca de}}(S)(x)\coloneqq T_{\text{casi}}(S)(x)\coloneqq\begin{cases} +\sqrt{\frac{1}{2}S(x)}, & x\in[0,\frac{1}{2}];\\ +1-\sqrt{\frac{1}{2}(1-S(x))}, & x\in[\frac{1}{2},1]. +\end{cases} +\] + +\end_inset + + +\end_layout + +\begin_layout Standard +Lo que en lógica clásica son paradojas, en lógica difusa es una +\series bold +media verdad +\series default + o +\series bold +media falsedad +\series default + (grado de pertenencia +\begin_inset Formula $\frac{1}{2}$ +\end_inset + +). +\end_layout + +\begin_layout Standard +Una +\series bold +proposición borrosa atómica +\series default + es una expresión de la forma +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $x$ +\end_inset + + es +\begin_inset Formula $P$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + o +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $x$ +\end_inset + + es +\begin_inset Formula $P$ +\end_inset + + es +\begin_inset Formula $C$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, donde +\begin_inset Formula $x$ +\end_inset + + es una variable libre, +\begin_inset Formula $P$ +\end_inset + + un conjunto borroso que representa la propiedad y +\begin_inset Formula $C$ +\end_inset + + un +\series bold +cualificador de certeza +\series default +, una función +\begin_inset Formula $[0,1]\to[0,1]$ +\end_inset + + de entre las siguientes: +\begin_inset Formula +\begin{align*} +\text{cierto}(x) & \coloneqq x, & \text{falso}(x) & \coloneqq1-x,\\ +\text{muy cierto}(x) & \coloneqq x^{2}, & \text{muy falso}(x) & \coloneqq(1-x)^{2},\\ +\text{bastante cierto}(x) & \coloneqq\sqrt{x}, & \text{bastante falso}(x) & \coloneqq\sqrt{1-x}. +\end{align*} + +\end_inset + +Una +\series bold +proposición borrosa compuesta +\series default + es una expresión de la forma +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $p$ +\end_inset + + and +\begin_inset Formula $q$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $p$ +\end_inset + + or +\begin_inset Formula $q$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + o +\begin_inset Quotes cld +\end_inset + +not +\begin_inset Formula $p$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, donde +\begin_inset Formula $p$ +\end_inset + + y +\begin_inset Formula $q$ +\end_inset + + son proposiciones borrosas (simples o compuestas). +\end_layout + +\begin_layout Standard +La +\series bold +función de pertenencia +\series default + de una proposición borrosa es +\begin_inset Formula +\begin{align*} +\mu_{x\text{ es }P} & \coloneqq P, & \mu_{x\text{ es }P\text{ es }C} & \coloneqq C\circ P, & \mu_{\text{not }p} & \coloneqq N\circ P,\\ +\mu_{p\text{ and }q}(x,y) & \coloneqq p(x)*q(y), & \mu_{p\text{ or q}}(x,y) & \coloneqq p(x)\oplus q(y), +\end{align*} + +\end_inset + +tomando +\begin_inset Formula $*$ +\end_inset + + y +\begin_inset Formula $\oplus$ +\end_inset + + conjugadas respecto a +\begin_inset Formula $N$ +\end_inset + +. + Las proposiciones borrosas son sentencias sobre un concepto sin definición + precisa, permitiendo expresar ideas subjetivas con distintas interpretaciones. +\end_layout + +\begin_layout Standard +El +\series bold +razonamiento aproximado +\series default + permite razonar sobre proposiciones imprecisas. + Una +\series bold +regla IF-THEN borrosa +\series default + es una expresión +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $\text{IF }u\text{ es }A\text{ THEN }v\text{ es }B$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +. + Si +\begin_inset Formula $A$ +\end_inset + + se define sobre el universo +\begin_inset Formula $U$ +\end_inset + + y +\begin_inset Formula $B$ +\end_inset + + sobre +\begin_inset Formula $V$ +\end_inset + +, esta regla se entiende como una relación entre +\begin_inset Formula $U$ +\end_inset + + y +\begin_inset Formula $V$ +\end_inset + +, la +\series bold +implicación borrosa +\series default + +\begin_inset Formula $R_{A\to B}:U\times V\to[0,1]$ +\end_inset + + dada por +\begin_inset Formula $R_{A\to B}(u,v)\coloneqq I(A(u),B(v))$ +\end_inset + +, donde +\begin_inset Formula $I:[0,1]\times[0,1]\to[0,1]$ +\end_inset + + es una +\series bold +función de implicación +\series default +. + Algunas funciones de implicación: +\end_layout + +\begin_layout Enumerate + +\series bold +Interpretación clásica: +\series default + +\begin_inset Formula $I(x,y)\coloneqq N(x)\oplus y$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate + +\series bold +Dienes-Rescher: +\series default + +\begin_inset Formula $I_{D}(x,y)\coloneqq\max\{1-x,y\}$ +\end_inset + + (interpretación clásica con las normas usuales). +\end_layout + +\begin_layout Enumerate + +\series bold +Lukasiewicz: +\series default + +\begin_inset Formula $I_{Lu}(x,y)\coloneqq\min\{1,1-x+y\}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate + +\series bold +Zadeh: +\series default + +\begin_inset Formula $I_{Z}(x,y)\coloneqq\max\{\min\{x,y\},1-x\}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate + +\series bold +Gödel: +\series default + +\begin_inset Formula $I_{G}(x,y)\coloneqq\begin{cases} +1, & x\leq y;\\ +y, & \text{en otro caso}. +\end{cases}$ +\end_inset + + +\end_layout + +\begin_layout Standard +Se tiene +\begin_inset Formula $I_{Z}\leq I_{D}\leq I_{Lu}$ +\end_inset + +. + Definiendo +\begin_inset Formula $I(x,y)\coloneqq x*y$ +\end_inset + + obtenemos: +\end_layout + +\begin_layout Enumerate + +\series bold +Mandami: +\series default + +\begin_inset Formula $I_{M}(x,y)\coloneqq\min\{x,y\}$ +\end_inset + +. +\end_layout + +\begin_layout Enumerate + +\series bold +Larsen: +\series default + +\begin_inset Formula $I_{L}(x,y)\coloneqq xy$ +\end_inset + +. +\end_layout + +\begin_layout Standard +Estas funciones se basan en una interpretación +\begin_inset Quotes cld +\end_inset + +local +\begin_inset Quotes crd +\end_inset + + de la implicación, en la que +\begin_inset Formula $P\to Q$ +\end_inset + + equivale a +\begin_inset Formula $P\land Q$ +\end_inset + + si se cumple +\begin_inset Formula $P$ +\end_inset + + y se ignora en otro caso. + Si hace falta una interpretación global como en la lógica clásica, hay + que usar una como las de la primera lista. +\end_layout + +\begin_layout Standard +Reglas lógicas: +\end_layout + +\begin_layout Itemize + +\series bold +Modus ponens generalizado: +\series default + Dados los conjuntos borrosos +\begin_inset Formula $A$ +\end_inset + + y +\begin_inset Formula $A'$ +\end_inset + + sobre +\begin_inset Formula $U$ +\end_inset + + y +\begin_inset Formula $B$ +\end_inset + + sobre +\begin_inset Formula $V$ +\end_inset + +, si +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $x$ +\end_inset + + es +\begin_inset Formula $A'$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + e +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $\text{IF }x\text{ es }A\text{ THEN }y\text{ es }B$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, entonces +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $y$ +\end_inset + + es +\begin_inset Formula $A'\circ R_{A\to B}$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +. +\end_layout + +\begin_layout Itemize + +\series bold +Modus tollens generalizado: +\series default + Dados los conjuntos borrosos +\begin_inset Formula $A$ +\end_inset + + sobre +\begin_inset Formula $U$ +\end_inset + + y +\begin_inset Formula $B$ +\end_inset + + y +\begin_inset Formula $B'$ +\end_inset + + sobre +\begin_inset Formula $V$ +\end_inset + +, si +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $y\text{ es }B'$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + e +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $\text{IF }x\text{ es }A\text{ THEN }y\text{ es }B$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, entonces +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $x\text{ es }R_{A\to B}\circ B'$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +. +\end_layout + +\begin_layout Standard +Si la función de implicación es la t-norma, al aplicar modus ponens sobre + +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $x\text{ es }A'$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + e +\begin_inset Quotes cld +\end_inset + +IF +\begin_inset Formula $x$ +\end_inset + + es +\begin_inset Formula $A$ +\end_inset + + THEN +\begin_inset Formula $y$ +\end_inset + + es +\begin_inset Formula $B$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + +, se obtiene +\begin_inset Quotes cld +\end_inset + + +\begin_inset Formula $y\text{ es }B'$ +\end_inset + + +\begin_inset Quotes crd +\end_inset + + con +\begin_inset Formula +\[ +B'(y)=\sup_{u\in U}(A'(u)*I(A(u),B(v)))=\sup_{u\in U}(A'(u)*A(u))*B(v), +\] + +\end_inset + +y llamamos +\series bold +\emph on +\lang english +degree of fulfillment +\series default +\emph default +\lang spanish + a +\begin_inset Formula +\[ +\text{DOF}(A',A)\coloneqq\sup_{u\in U}(A'(u)*A(u))=\sup_{u\in U}(A'\cap A)(u), +\] + +\end_inset + +con lo que +\begin_inset Formula $B'(y)=\text{DOF}(A',A)*B(v)$ +\end_inset + +. + Por ello las implicaciones de Mandami y Larsen son muy eficientes y son + las más usadas. + Además hay una interpretación gráfica intuitiva: para calcular la implicación + de Mandami, se toma el supremo del mínimo de +\begin_inset Formula $A$ +\end_inset + + y +\begin_inset Formula $A'$ +\end_inset + +, que será el DOF, y se corta +\begin_inset Formula $B$ +\end_inset + + por este punto (tomando el mínimo) para obtener +\begin_inset Formula $B'$ +\end_inset + +, y para la de Larsen se toma el supremo del producto de +\begin_inset Formula $A$ +\end_inset + + y +\begin_inset Formula $A'$ +\end_inset + + y se multiplica +\begin_inset Formula $B$ +\end_inset + + por este número. +\end_layout + +\end_body +\end_document |
