📄 gaw.ps
字号:
2684(the)S2797(intrinsic)S2990 3606(-)U540 3684(p)U540 3606(tolerance)U804(of)S883(noise)S1045(exhibited)S1312(by)S1401(the)S1504(genetic)S1716(algorithm)S1994(which)S2178(arises)S2351(out)S2458(of)S2536(the)S2639(repeated)S2884(sam)S573 3684(ling)U702(of)S784(small)S953(chunks)S1166(of)S1247(the)S1353(genetic)S1568(material)S1808(\(so)S1915(called)S2097(schemata\))S2389(over)S2532(a)S2587(number)S2814(of)S2895(gen-)S540 3942(T)U540 3762(erations.)U580 3942(here)U715(is)S781(a)S832(discussion)S1129(of)S1206(the)S1308(issues)S1488(in)S1561(selecting)S1816(suitable)S2042(population)S2345(sizes)S2495(in)S2568(Goldberg)S2839(1988.)S3 F72 Z1800 4383(11)UEP%%Page: ? 13BP1 F66 Z540 696(F)U3 F72 Z540 516(5.4.2.)U750(Fitness)S990(Scaling)S1 F66 Z577 696(itness)U750(scaling)S959(occurs)S1154(between)S1396(the)S1499(production)S1807(of)S1885(new)S2018(individuals)S2333(in)S2407(the)S2510(population)S2814(and)S2932(the)S2990 774(-)U540 852(b)U540 774(use)U655(of)S737(their)S883(\256tness)S1078(values)S1272(for)S1375(selection.)S1673(It)S1739(is)S1809(a)S1864(method)S2087(of)S2168(adjusting)S2435(the)S2541(probability)S2855(distri)S573 852(ution)U735(which)S922(determines)S1236(the)S1342(likelihood)S1634(of)S1715(an)S1803(individual)S2095(being)S2267(selected)S2504(for)S2607(breeding.)S2902(It)S2968(is)S2990 930(-)U540 1008(t)U540 930(usually)U752(used)S895(to)S968(emphasise)S1264(the)S1366(relativel)S1580(y)S1635(small)S1799(differences)S2113(in)S2186(relative)S2404(\256tness)S2595(when)S2760(a)S2811(popula)S558 1008(ion)U669(begins)S868(to)S946(converge.)S1253(Without)S1495(it,)S1575(the)S1682(rate)S1807(of)S1889(convergence)S2248(will)S2377(slow)S2528(down)S2701(as)S2782(diversity)S540 1266(T)U540 1086(decreases)U814(and)S931(most)S1081(individuals)S1395(in)S1468(the)S1570(population)S1873(have)S2019(similar)S2223(\256tnesses.)S580 1266(he)U665(kind)S804(of)S881(\256tness)S1072(scaling)S1280(employed)S1561(depends)S1799(on)S1887(the)S1989(value)S2153(of)S2230(the)S2332(corresponding)S2731(input)S2888(vari-)S2 F540 1524(N)U1 F540 1344(able)U671(which)S854(has)S964(one)S1081(of)S1158(the)S1260(following)S1538(values.)S2 F584 1524(one)U1 F690(No)S793(scaling.)S1040(An)S1143(individual's)S1479(scaled)S1665(\256tness)S1856(value)S2020(is)S2086(the)S2188(same)S2345(as)S2422(its)S2506(unscaled)S2758(value.)S2 F540 1704(Linear)U1 F690 1782(Each)U848(individual's)S1189(scaled)S1380(\256tness)S1576(f')S1647(is)S1718(calculat)S1921(ed)S2010(from)S2165(its)S2254(unscaled)S2510(\256tness)S2705(f)S2753(according)S690 1860(to)U763(the)S865(formula)S810 2040(f')U876(=)S935(a.f)S1025(+)S1084(b)S690 2244(w)U(here)R878(a)S934(and)S1056(b)S1116(are)S1223(chosen)S1433(so)S1519(that)S1644(the)S1751(mean)S1920(scaled)S2111(\256tness)S2307(is)S2378(equal)S2547(to)S2624(the)S2730(mean)S2898(uns-)S690 2400(m)U690 2322(caled)U859(\256tness)S1059(of)S1145(the)S1256(population,)S1585(and)S1711(so)S1801(that)S1930(the)S2041(maximum)S2338(scaled)S2533(\256tness)S2733(is)S2807(a)S2866(given)S741 2400(ultiple)U930(of)S1007(the)S1109(maximum)S1397(unscaled)S1649(\256tness.)S1879(The)S2003(multiple)S2243(is)S2309(typically)S2560(two.)S3 F72 Z540 2808(5)U1 F66 Z540 2580(Several)U759(methods)S1004(of)S1081(\256tness)S1272(scaling)S1480(are)S1582(discussed)S1857(in)S1930(Goldberg)S2201(1989.)S3 F72 Z576 2808(.4.3.)U750(Breeder)S1022(Selection)S1 F66 Z540 2988(B)U(reeder)R776(selection)S1037(involves)S1288(choosing)S1554(a)S1611(number)S1840(of)S1923(individuals)S2243(according)S2530(to)S2608(\(scaled\))S2843(\256tness)S540 3246(T)U540 3066(which)U723(will)S847(be)S931(used)S1074(for)S1173(breeding.)S580 3246(he)U666(number)S891(chosen)S1098(depends)S1338(on)S1428(the)S1532(number)S1757(of)S1836(new)S1970(individuals)S2286(required,)S2546(which)S2731(is)S2799(the)S2902(pro-)S540 3402(b)U540 3324(duct)U678(of)S758(the)S863(current)S1074(population)S1380(size)S1507(and)S1627(the)S2 F1732(generation)S2042(gap.)S1 F2204(The)S2330(latter)S2488(is)S2556(an)S2642(input)S2801(variable)S573 3402(etween)U783(0)S840(and)S959(1)S1016(which)S1201(represents)S1492(the)S1596(proportion)S1898(of)S1977(the)S2081(current)S2291(population)S2595(replaced)S2840(during)S540 3660(T)U540 3480(each)U682(generation.)S580 3660(he)U666(method)S886(of)S964(selecting)S1220(the)S1323(individuals)S1638(depends)S1877(on)S1966(the)S2069(value)S2234(of)S2312(the)S2415(input)S2573(variable)S2 F2807(breeder)S540 3918(R)U540 3738(selection:)U580 3918(oulette)U1 F690 3996(T)U(his)R836(method)S1062(is)S1135(so)S1223(named)S1426(because)S1662(of)S1745(its)S1835(similarity)S2114(to)S2193(spinning)S2448(a)S2505(roulette)S2733(wheel.)S2957(In)S2983 4074(e)U690 4152(p)U690 4074(effect,)U882(an)S970(imaginary)S1262(roulette)S1488(wheel)S1671(is)S1741(marked)S1964(out)S2074(with)S2216(one)S2336(slot)S2456(per)S2565(individual)S2856(in)S2932(th)S723 4152(opulation,)U1011(but)S1117(the)S1219(slots)S1362(are)S1464(of)S1541(differing)S1793(sizes)S1943(giving)S2133(some)S2294(individuals)S2608(a)S2659(better)S2830(chance)S3 F72 Z1800 4383(12)UEP%%Page: ? 14BP1 F66 Z690 516(o)U(f)R773(being)S947(selected)S1186(for)S1291(breeding)S1549(than)S1690(others.)S1918(By)S2023(making)S2248(the)S2356(slot)S2479(size)S2609(proportional)S2961(to)S2979 594(y)U690 672(b)U690 594(the)U800(\(scaled\))S1038(\256tness)S1237(of)S1322(each)S1472(individual,)S1785(the)S1895(\256tter)S2049(individuals)S2371(have)S2525(a)S2584(correspondingl)S723 672(etter)U861(chance)S1065(of)S1142(being)S1310(selected)S1543(and)S1660(passing)S1880(on)S1968(their)S2110(characteri)S2368(stics.)S2979 852(g)U690 930(s)U690 852(The)U817(imaginary)S1108(wheel)S1290(is)S1359(spun)S1509(once)S1658(for)S1760(each)S1905(individual)S2196(required,)S2457(one)S2576(individual)S2866(bein)S716 930(elected)U930(per)S1043(spin.)S1221(This)S1366(allows)S1566(some)S1733(individuals)S2053(to)S2132(be)S2222(selected)S2461(more)S2624(than)S2765(once)S2917(and)S2 F540 1188(E)U1 F690 1008(others)U873(not)S979(to)S1052(be)S1136(selected)S1369(at)S1438(all.)S2 F580 1188(xpected)U802(Value)S1 F690 1266(T)U(here)R872(is)S944(a)S1001(potential)S1258(problem)S1505(with)S1650(roulette)S1878(wheel)S2063(selection)S2324(because)S2560(it)S2624(is)S2696(a)S2753(stochastic)S690 1422(m)U690 1344(process.)U954(In)S1036(other)S1198(words,)S1404(its)S1493(random)S1721(element)S1955(allows)S2153(some)S2318(individuals)S2636(to)S2713(be)S2801(selected)S741 1422(ore)U850(often)S1010(than)S1148(their)S1293(\256tness)S1487(deserves)S1739(\(and)S1881(others)S2067(to)S2143(be)S2230(selected)S2465(less)S2588(often\).)S2808(Expect-)S690 1578(s)U690 1500(ed)U778(value)S945(selection)S1203(reduces)S1429(this)S1549(stochastic)S1833(error)S1986(by)S2077(ensuring)S2329(that)S2452(no)S2543(individual)S2834(can)S2950(be)S716 1578(elected)U925(more)S1084(than)S1221(one)S1339(more)S1497(time)S1636(than)S1772(it)S1831(deserves.)S2120(\(Obviously)S2440(some)S2602(stochastic)S2884(error)S2990 1656(-)U690 1734(t)U690 1656(must)U846(remain)S1056(because)S1292(the)S1400(number)S1629(of)S1712(times)S1882(and)S2004(individual)S2297(is)S2368(selected)S2606(must)S2761(be)S2850(an)S2939(in)S708 1734(eger)U843(whereas)S1081(its)S5 F1165(")S1 F(selection)R1448(merit)S5 F(")R1 F1636(is)S1702(a)S1753(real)S1873(number\).)S2979 1914(g)U540 1992(1)U540 1914(Both)U2 F703(generation)S1023(gap)S1 F1156(and)S1285(several)S1505(kinds)S1682(of)S2 F1771(breeder)S2010(selection)S1 F2277(are)S2391(discussed)S2678(in)S2763(Goldber)S573 1992(989.)U3 F72 Z540 2220(5)U(.4.4.)R750(Generation)S1122(Gap)S1 F66 Z540 2400(T)U(he)R2 F675(generation)S992(gap)S1 F1123(input)S1290(variable)S1533(determines)S1853(the)S1965(proportion)S2275(of)S2362(each)S2514(the)S2626(population)S2939(re-)S3 F72 Z540 2706(5)U1 F66 Z540 2478(placed)U733(during)S927(each)S1069(generation.)S1407(See)S1524(breeder)S1743(selection)S1998(above.)S3 F72 Z576 2706(.4.5.)U750(Mates)S962(Selection)S1 F66 Z540 2886(F)U(ollowing)R840(selection)S1102(of)S1186(a)S1244(pool)S1390(of)S1474(individuals)S1795(for)S1901(breeding,)S2177(pairs)S2334(are)S2443(taken)S2614(from)S2771(this)S2895(pool)S540 3042(h)U540 2964(and)U668(bred)S818(to)S901(produce)S1145(a)S1206(pool)S1355(of)S1442(progeny.)S1729(The)S1863(input)S2030(variable)S2 F2273(mates)S2459(selection)S1 F2724(determines)S573 3042(ow)U676(these)S833(pairs)S983(are)S1085(chosen.)S1329(Currently)S1603(only)S1742(one)S1859(method)S2078(is)S2144(supported:)S2 F540 3222(Random)U1 F690 3300(Each)U847(individual)S1139(chosen)S1348(for)S1451(mating)S1659(from)S1812(the)S1917(breeding)S2172(pool)S2314(is)S2383(selected)S2619(at)S2691(random)S2917(and)S540 3558(I)U690 3378(is)U756(immediat)S1003(ely)S1105(removed)S1357(from)S1507(the)S1609(pool)S1748(to)S1821(prevent)S2040(it)S2098(being)S2266(selected)S2499(again.)S562 3558(n)U627(this)S754(implement)S1034(ation)S1197(all)S1294(individuals)S1618(are)S1730(identical)S1986(and)S2112(so)S2202(purely)S2401(random)S2633(selection)S2897(of)S2983(a)S2986 3636(s)U540 3714(r)U540 3636(mate)U696(is)S769(always)S981(valid.)S1180(However,)S1467(more)S1630(complicat)S1888(ed)S1978(schemes)S2229(are)S2337(feasible)S2569(where)S2758(mating)S2968(i)S562 3714(estricted)U810(in)S887(some)S1052(way,)S1204(perhaps)S1434(to)S1510(simulate)S1757(the)S1862(formation)S2146(of)S2226(niche)S2393(populations)S2725(or)S2805(species.)S540 3870(d)U540 3792(This)U693(is)S773(discussed)S1062(further)S1277(in)S1364(Goldberg)S1649(1989)S1817(\(p188-197\).)S2189(See)S2320(also)S2462(section)S2683(5.4.9)S2851(which)S573 3870(escribes)U807(dispersal)S1063(by)S1151(crowding.)S3 F72 Z1800 4383(13)UEP%%Page: ? 15BP1 F66 Z540 696(H)U3 F72 Z540 516(5.4.6.)U750(Mating)S1 F66 Z588 696(aving)U759(selected)S995(a)S1049(pair)S1176(of)S1256(individuals)S1573(for)S1675(mating,)S1899(they)S2037(are)S2142(mated)S2326(to)S2401(produce)S2637(new)S2771(individu-)S540 852(o)U540 774(als)U636(which)S820(are)S923(collecte)S1126(d)S1182(in)S1256(a)S1308(pool)S1448(of)S1526(progeny.)S1804(The)S1929(method)S2149(used)S2293(is)S2360(determined)S2678(by)S2767(the)S2870(value)S573 852(f)U617(the)S2 F719(mating)S1 F924(input)S1081(variable,)S1331(but)S1437(this)S1554(currently)S1813(only)S1952(supports)S2198(one)S2315(method:)S2 F540 1032(Simple)U1 F690 1110(Simple)U904(mating)S1114(produces)S1380(two)S1507(progeny)S1751(from)S1907(two)S2034(parents)S2252(as)S2334(follows.)S2598(First)S2746(a)S2802(copy)S2957(of)S2990 1188(f)U690 1266(w)U690 1188(each)U844(parent)S1042(is)S1120(taken)S1296(and)S2 F1425(crossover)S1 F1715(is)S1792(applied)S2018(to)S2102(produce)S2347(two)S2479(individuals)S2804(each)S2957(o)S738 1266(hich)U875(receives)S1114(some)S1277(genetic)S1489(material)S1726(from)S1877(both)S2017(parents.)S2269(Finally,)S2 F2495(mutation)S1 F2752(is)S2819(applied)S540 1524(C)U690 1344(to)U763(each)S905(individual)S1193(which)S1376(may)S1511(introduce)S1781(a)S1832(random)S2055(change)S2263(to)S2336(the)S2438(genetic)S2649(material)S2863(.)S584 1524(rossover)U830(and)S947(mutation)S1202(are)S1304(described)S1578(in)S1651(the)S1753(following)S2031(sections.)S2990 1704(-)U540 1782(a)U540 1704(Currently)U819(only)S963(simple)S1165(mating)S1374(is)S1444(supported,)S1747(but)S1857(many)S2029(variations)S2314(can)S2431(be)S2519(envisaged,)S2825(for)S2928(ex)S569 1782(mple)U726(incorporating)S1106(other)S1267(genetic)S1482(operators)S1752(than)S1890(crossover)S2168(and)S2288(mutation.)S2585(These)S2767(operators)S540 1938(n)U540 1860(are)U650(copied)S854(directly)S1083(from)S1240(natural)S1451(processes)S1733(and)S1857(their)S2006(are)S2115(many)S2290(other)S2454(such)S2604(ope
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -