ࠬᎈ၍ଣኪజ ୋɖ՜ ୋɚಂ 2005ϋ7˜ Journal of Risk Management July 2005 -164 ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺķ ɓࡈᔊఊٙᒄ҅ᅼۨ A Simple Model of Herd Behavior in a Stock Market under Asymmetric Information ∗∗∗ੵဤ (Alex . Chang) ᄎၪ( Victor W. Liu) ࠅ ͉˖˸ৃࢹбᒄ҅ઞীҳ༟ɛίٰ̹༟ৃʔ࿁၈ɨʘҁΌԎˤѩፅٙ༧Бމdҳ༟٫జཇɽʷٙԉܓdઞীί༟ৃʔ࿁၈ɨd˴ɢٙҳ༟Бމהб࿁˒ՈϞจ່ٙৃࢹdԨіˏ˒༧ආҳ༟dϓ༧ҳ༟Бމf͉˖ʱй૿ଌόѩፅၾʱᕎόѩፅආБᒄ҅પစdᐏߧπίɚ၇૿ଌόѩፅf˴ࠅഐሞމ: ՈϞᜳஷऊࢹٙ˴ɢҳ༟٫הમ՟ٙҳ༟Бމึᙑ׳ৃࢹdіˏʔՈϞᜳஷऊࢹٙ˒༧ආd˸Җϓ༧ҳ༟Бމf˒̙˸ᔟ͟˴ɢʘҳ༟Бމהбٙৃࢹdમ՟Чٙҳ༟Бމf͵у˒ٙ༧БމίᗇՎ̹ఙʕ݊πίdϾ˲̹ఙ˴ɢၾ˒ٙҳ༟Бމ݊ଣeՈϞഄଫจ່ٙf ᗫᒟ൚jৃࢹбᒄ҅eҁΌԎˤѩፅe༧Бމf Abstract This paper discusses Perfect Bayesian herd behavior in a stock market under asymmetric information. We construct a signaling game model to obtain the following main conclusions: The informed main investor's strategy signals his private information about return types to uninformed investors. Uninformed investors, in mixed equilibriums, had better to follow the informed investor's strategy. Consequently, herd behavior exists in the stock market. The investment behavior between informed main investor and uninformed investors is rational. Keywords: Signaling Game, Perfect Bayesian Equilibrium, Herd Behavior. ∗ ͭ܈؇߅ҦɽኪΆ၍ӻਓબdAssociate Professor, Dep. of Business Administration, National Pingtung University of Science and Technology, Taiwan, . ∗∗ ᘒശვБԫڗ/ͭʕʆɽኪΆ၍ӻબdPresident, Bowa Bank, and Professor, Dep. of Business Administration, National Sun Yat-Sen University, Taiwan, .
136ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ 1. ၫሞ ෂ୕ٰٙୃ̹ఙଣሞႩމdҳ༟ዚٙӔഄᅼόˀᏐՉଣɛٙଣཫಂdהϞٙӔഄޫԱኽႎණٙϞࣖ༟ৃආБfШ̤̮ɓࡈˀٙሞᓃۆಯࢮৃࢹʫ࢙ၾӔഄБމٙᗫஹdԨႩމӔഄ̙ঐ݊Ա໊ٙːଣආБٙf Keynes (1936) ίՉɓছѩፅଣሞ࿁ڗಂҳ༟٫࿁̹ఙᅂᚤၾᆽڭϞࣖҳ༟ٙঐɢܵᕿဲ࿒ܓfί˼ٙᝈᓃʕdҳ༟٫ϽᅇІʉᑊᚑ̙ঐٙಯฦdϾʔᗴԱኽՉኹϞٙӷϞ༟ৃၾڦׂආБӔഄfΪϤdKeynes ܔᙄਖ਼ุٙଣɛν؈ᗫʲՉ˼ɛνО൙ሞ˼ٙБމࣛdᏐ༈༧ɽ(follow the herd)f ༧Бމ(herd behavior)จܸɓ໊ҳ༟ɛίӚϞОਿ͉ଣ͟(without fundamental reasons)ʘɨમ՟Чҳ༟Бމٙɓ၇ତ(Banerjee, 1992; Froot, Scharfstein & Stein, 1992)fν؈ίᗇՎ̹ఙʕεᅰҳ༟ɛʔሞՉ݊щኹϞӷϞৃࢹdɓ݉༧εᅰɛٙҳ༟БމආБҳ༟ࣛdکϓᗇՎ̹ఙٙ༧ҳ༟Бމ (Laffont & Maskin, 1990; Banerjee, 1992; Froot et al, 1992)fϤɓ༧БމจܸࡈɛίࣛගၾІ್ଣ౽ٙࠢՓɨવࡈɛٙ༟ৃϾમ͜εᅰɛٙৃࢹ(Shiller, 1995)f ઞীৌਕӔഄٙ༧БމٙӺεd༧ኽDevenow & Welch (1996) ʘʱᗳd༧БމԱՉ݊щଣʱϓଣ༧Бމ(rational herding)ၾڢଣ༧Бމ(non-rational herding)fܝ٫ৎΪ໊ʔଣːଣतሯd͟ॹ˶ᘌᔫٙᅰଣਿᓾd˖ᘠʕʘ༧Бމ฿ܸۃ٫މ˴fϓଣ༧БމცࠅπίɓࡈБމዚՓdνᝈ࿀˼ɛٙঐɢiאԱΝৃࢹପ͛ٙᄿعۆd˸ٰᄆԐැމ˾ڌf ෂ୕ٙଣ༧БމԱᅼۨપኬतd̙ʱމɧᗳj ୋɓᗳ݊˴ଣɛ{˾ଣɛᅼۨ(reputation/principal-agent model)fՉࠅϙ݊ଣɛίϽᅇڦᚑࣖ؈ɨdึλᅼͷ˼ɛٙБމdҁΌׁଫӷϞ༟dৃ˸бՈϞ৷ঐɢٙৃࢹfνHolmstrom (1982a; b)eHolmstrom & Joan (1986)eHong, Kubik, & Solomon (2000)eEffinger & Polborn (2001)eHo, Keller & Keltyka (2002)ίଣɛϽᅇ௶ਗ̹ఙ൙ᄆٙۃᕚɨdઞীҳ༟ӔഄБމd೯ତҳ༟ଣɛ௰ԳӔഄ݊༧ᎇ˼ɛٙҳ༟БމfAllen & Gorton (1993)˸ՈϞ൯ආ፯ᛆٙଣɛ۰ߒணࠇdႭίʔՈᜳஷऊࢹٙࢁл٫ӚϞஈၮૢಛɨdึପ͛˾ଣਪᕚfDow & Gorton (1994)˸ҳ༟ଡ଼Υଣɛ۰ߒணࠇʿ̹ఙ௴ி٫ٙڦׂމ˴ൿdႭᜳஷऊࢹଣɛٙБމ̀މጐҳ༟БމfScharfstein & Stein (1990) ༶͜ɓࡈኪ୦ᅼۨႭ
ࠬᎈ၍ଣኪజ 137ୋɖ՜ ୋɚಂ2005ϋ7˜ dઞীଣɛίϽᅇ௶ਗ̹ఙ൙ᄆۃᕚɨٙҳ༟Бމf˴ࠅഐሞ݊ଣɛӋՉڦᚑࣖ͜ɽʷઋҖɨd˼ึમ՟ᅼͷ˼ɛٙҳ༟ӔഄʘБމdҁΌʔϽᅇՉኹϞٙӷϞ༟ৃf ୋɚᗳ݊ৎΪ༟ৃᐏϾᐏлٙజཇ̮๐ᅼۨ(payoff externalities model)fLaffont & Maskin (1990) ˸ৃࢹбᒄ҅ઞীίʔҁΌᘩنًرɨdՈᜳஷऊࢹٙ˴ɢၾΝሯ˒ٙʹତdӺഐሞႩމ˴ɢλ༟ପॆྼజཇٙᜊମʔɽٙઋҖd˸ᐏ՟൴ᕘజཇfFroot et al (1992) ၾBrennan (1990) ۆઞীᗇՎ̹ఙʕdಂࢁл٫ٙБމf˴ࠅഐሞ݊ᗇՎ̹ఙʕࢁл٫ආБಂҳ༟ࣛd˼ࡁึணجə༆Չ˼ࢁл٫הኹϞٙӷϞ༟ৃeવІʉٙӷϞৃࢹdԨԴ͜Νٙ༟ৃආБΝٙҳ༟БމGraham, 1999fуԴவԬ༟ৃၾਿ͉ࠦ૩ೌᗫf ୋɧᗳۆ݊ᝈ࿀Ԩ˼ɛБމהᙑ׳ٙϞ͜ৃࢹdԨྐྵ̙׳ӷϞٙৃࢹd၈މৃࢹ̮๐ᅼۨ(information externalities/cascades model)fBanerjee (1992)eKhanna & Slezak (1998) ˸ஹᚃ(sequential)ӔഄᅼۨઞীӔഄ٫ٙБމf˴ࠅഐሞ݊ίԎˤॶѩፅ(Bayesian Nash Equilibrium)ɨdʔሞՉ݊щኹϞӷϞ༟ৃd௰ԳٙӔഄБމ݊׳ӷϞৃࢹdમ՟ၾ˼ɛɓߧٙ༧БމfBikhchandani, Hirshleifer & Welch (1992)ઞীɓছٟٙึБމd೯ତ༟ৃݴਗ(informational cascades)݊пڗɓߧБމٙ˴ࠅԸ๕dɓ͇༟ৃݴਗБϓdܝᚃ٫ึ׳ӷϞڦׂ༧ۃɛٙБމfWelch (1992) ˸ஹᚃᅼۨઞীอٰ೯Б(IPO) ʘוቖБމfܝᚃҳ༟٫ᝈ࿀༰Ϙҳ༟٫ٙҳ༟Бމdкᓙอٰɪ̹ࠈᄆ݊щΥଣkഐ؈ϓණҳ༟Бމdอɪٰ̹ୃ̀ცЭᄆוቖʑঐϓ̌f ίʫ༧БމٙᗫӺʕdɽε˸˴ɢʹމઞীࠠːνҽ֚e؍ਿৌၾᄎ͗ޜd1996iದ౽ሬd2002fεЗኪ٫Ⴉމၽᝄٰୃ̹ఙҳዚं؟ዢێdҳ༟ɛᆠহᇞආ̈රᅃځd1995iၽᝄٰ̹ʔШ̂တʫᇞʹeױٰᄆeᐽٰ̹ٙତdϾ˲ҳ༟˒ٛͦ༧d੬༧ᎇ˴ɢeٰʾٟආ̈රઽпd1993iර◕చd1988i˴ɢʔШл͜ʫऊࢹЪމʹʘԱኽdԨ˲ঐ͍ᆽཫ͊ԸٰୃٙॆྼᄆЗϾᐏлdΪϤ˴ɢʹԑ˸Ъމ˒ආٰ̈ୃʘਞϽړᜑˢၾᐷቤρd1994f̤̮d΅ਿږኹϞ൯ආҳ༟ࣛዚٙঐɢdՉଣɛ͵ϞৣΥɽٰ؇ආБقЪБމ̙ٙঐเಃϓd1993fЇɓছ˒ҳ༟ɛ߰ঐ༧ᎇ˴ɢආБҳ༟͵ঐᐏ൴ᕘజཇˮΌd1991iੵΆd1992f್Ͼ͟˒੬݊༟ৃໝܝ٫dה˸੬൯ί௰৷ᓃԨርί௰Эᓃf݄͛ʩd2001f ̤̮Աҽ֚e؍ਿৌၾᄎ͗ޜ(1996)eLee, Lin, & Liu (1999)ʘྼᗇӺᜑͪdၽᝄٰୃ̹ఙʫᅂᚤɢ௰ɽٙҳ༟ɛމɽۨҳ༟ɛא˴ɢ
138ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ ၾዚҳ༟ɛdˈՉۃ٫ٙ༟ৃ௰މᜳஷiɓছ˒ҳ༟ɛۆ௰ʔᜳஷd࿁ৃࢹˀᏐ͵௰፰ᇠfͷගϞᗫ˒˴ɢආ̈Шಞቊฦ̰ٙ˖dν1ቮeࢁe૨ɧӉϜഃһೌجးࣣfϾ͉˖הઞীٰ̹ٙ˴ɢ˸ɨᔊ၈˴ɢʔШܼ̍ɪ̹ʮ̡˴ɢd˲عܸהϞ࿁ٰᄆပൻՈϞᅂᚤɢٙɽۨҳ༟ዚאІ್ɛf ၝΥɪࠑʫ˖ᘠٝd˴ɢʔШ࿁ᗇՎᄆࣸՈϞᅂᚤdһঐீཀৃࢹٙ౧ᚣdҷᜊՉ˼ҳ༟٫ٙڦׂ (Laffont & Maskin, 1990)iՈᜳஷऊࢹ2ٙ˴ɢһΪϤϾᐏ՟൴ᕘజཇfኽ Ippolito (1989)˸ఊΪ९ Sharpe-Lintner ѩፅᅼόආБӺd೯ତՈӷϞ༟ৃٙΝਿږଣɛd̙ᐏ՟ᜑഹٙ൴ᕘజཇiШ Elton, Gruber, Das & Hklarka (1991)˸εΪ९༟ପࠈᄆᅼόӺۆᜑͪdΝਿږၾৗ;ਿږଣɛٙ൴ᕘజཇd̻ѩϾԊމࠋfΪϤ˴ɢ݊щঐᐏ՟൴ᕘజཇd՟Ӕ݊щՈϞӷϞ༟ৃdʿνОீཀ̹ఙ౧ᚣٙৃࢹආБʹٙપሞᏐ᙮Υଣf͉˖ٙӺਗዚίމᗇՎ̹ఙʕ˒༧˴ɢٙҳ༟Бމܔͭɓࡈଣሞਿᓾf ˸ʫᗇՎ̹ఙϾԊd˴ɢίɨΐ̙ঐઋرɨd̙˸һϞࣖήኹϞݔत֛ᗇՎٙਿ͉༟ࣘνପุၾʮ̡͊Ը೯࢝˙Σeᐄᐑᘩٙᜊʷהପ͛ٙዚึၾ۾উe߅Ҧ௴อהˏ೯ٙᘩنᒈැഃഃj c ˴ɢމݔɪ̹ʮ̡אՉᗫڷΆุٙʫɛf d ˴ɢމݔɪ̹ʮ̡ٙᗫڷΆุўਿږeІᐄਠe̮༟אՉ̴جɛዚf e ˴ɢމݔɪ̹ʮ̡ٙʫᗫڷɛܼ̍ҳ༟ᚥਪʮ̡f ྼᗇ೯ତᗇՎ̹ఙʘዚҳ༟ɛගπί༧ҳ༟Бމٙ݊Kraus & Stoll (1972)fЇͦۃމ˟d̮ᗫ˖ᘠʕઞীᗇՎ̹ఙ༧Бމʥ˸ஹᚃӔഄٙৃࢹ̮๐ᅼۨމ˴νBanerjee, 1992eWelch, 1992eEffinger & Polborn, 2001dԨਗ਼Ӻණʕجɛගٙ༧Бމ̮νScharfstein & Stein, 1990eRama & Philippe, 1998eWermer, 1999eSushil & Sharma, 2000eChang, Cheng & Khorana, 2000iʫν؍ͺٓ1996eݚ᎑ё1997eߪ౮ψ1999eю݁ᆀ1999eᘽઓ҃2000eெࣖԽ2000eҽඩణ2001e৷ᅆޛ2003ၾᄎ͑ʠ2004fᜑˇ˸ɽ˒ၾ˒ගٙ༧БމމӺ˴ᕚNofsinger & Sias, 1999d˸ኪଣމӺ˴ൿ٫һ˹ʘᕍνf ̤̮d߰˸ኪଣމӺࣛdᅼόʕ௰Ոنᙄʘஈίም݊ୋɓࡈБਗ٫k(Who is the first mover?) (Shiller, 1995)މʡჿՉ˼ɛʔ݊ୋɓࡈБ 1 ሗਞϽৌৃ˜̊76Ї137ಂeʈਠࣛజ͏86ϋ1˜30˚ୋ̬وቮeࢁe૨f 2 Աړᜑˢၾᐷቤρ1994ʘӺഐ؈ᜑͪdٰ̹ʫᗫڷɛঐቇٙ൯ርࣛዚdԨΪϤϾᐏлf݂͉˖ٙணᏐ᙮Υଣf
ࠬᎈ၍ଣኪజ 139ୋɖ՜ ୋɚಂ2005ϋ7˜ ਗ٫k͟˒ҳ༟ɛɗৃࢹໝܝ٫݄͛ʩd2001e౷ཁπίਗeڋˀᏐʔԑٙତᔝૺጲd2002iɦ༧БމٙৎΪˀᏐอৃࢹϾڢၪܵࡈɛᑊᚑ݄͛ʩd2001f݂͉˖Ꮭਞৃࢹ̮๐ᅼۨٙၚग़d˸ৃࢹбᒄ҅ (signaling game)މݖઞীᗇՎ̹ఙ˒ί༟ৃʔ࿁၈ɨʘҁΌԎˤѩፅ (perfect Baysian equilibrium)ٙ༧БމfίՈϞᜳஷৃࢹٙ˴ɢЪމᒄ҅ʕୋɓࡈБਗ٫ɨdҳ༟٫జཇɽʷٙԉܓdઞীίԟԬत֛ૢɨd˒ҳ༟٫ึᅼͷ˴ɢٙҳ༟БމᏐ᙮Υଣf Ш͉˖ٙ༧Бމၾৃࢹ̮๐ᅼۨٙ༧Бމᅼۨʘ˴ࠅࢨମϞj a. ෂ୕ٙ༧Бމ݊͟ɓ໊ೌᗫৃࢹٙࡈɛ༧ኽᝈ࿀˼ɛٙБމϾϓfୋɓࡈБਗ٫݊ԱኽᎇዚᐏٙৃࢹආБӔഄd݂Бމ͵݊ᎇዚϾऊ(Banerjee, 1992iBikhchandan et al, 1992; Welch, 1992)dԨπίም݊ୋɓࡈБਗ٫ٙဲf͉˖˸ՈϞᜳஷৃࢹٙ˴ɢЪމᒄ҅ʕୋɓࡈБਗ٫dՉӔഄБމ݊ଣጐϾ˲ՈϞഄଫจ່f b. ᒄ҅ʕୋɓࡈБਗ٫˸ՈϞᜳஷৃࢹٙఊɓ˴ɢאණΥdՉҳ༟БމһՈϞҖϓ༧Бމ̜ٙɢdၾԫྼ༰މટڐf c. ෂ୕ٙ༧Бމعܸɓ໊ɛאዚʘගٙЧБމi͉˖ٙ༧БމഹࠠίᗇՎ̹ఙʕ˒༧˴ɢҳ༟ٙЧБމdɓ˙̹݊ఙ˴ɢdɓ˙݊˒f d. ͉˖˸ৃࢹбᒄ҅ઞীᗇՎҳ༟༧Бމdਞᒄʘᕐ˙ޫცਗ਼࿁˙ٙӔഄॶɝІʉٙӔഄՌᅰʕdɗଣٙӔഄБމf ͉˖ீཀଣሞٙપኬdಂૐ༺ՑɨΐӺͦٙj ίҳ༟ዚజཇɽʷٙͦᅺɨdбৃࢹ˸іˏ˒༧ආҳ༟dϓ༧ҳ༟Бމd݊щึΪމᅺٙᗇՎٙॆྼᄆЗۨ࿒ʔΝϾϞʔΝБމk˒ίᝈ࿀Ց˴ɢٙҳ༟БމהбٙৃࢹࣛdึίݔԬत֛ૢɨમ՟༧ආٙҳ༟Бމk͵уί༟ৃʔ࿁၈ɨd˴ɢٙҳ༟Бމ݊щб࿁˒ՈϞจ່ٙৃࢹk 2. ᒄ҅ഐ ᒄ҅ഐਿ͉Ⴍሗਞڝྡ 1 a. ਞᒄ٫j͉ᒄ҅ϞՇ˙ਞᒄ٫dɓ˙މ࿁ݔҳ༟ᅺٙᗇՎኹϞᜳஷऊࢹٙ˴ɢ(informed main investor)d˸Iڌi̤ɓ˙މʔՈϞᜳஷऊࢹٙΝሯ˒(uninformed investor)d˸U˾ڌfՇ٫ޫމࠬᎈʕͭ٫risk-neturalistf b. ༟ৃઋرj͉ᒄ҅ਿ͉ணމ༟ৃʔ࿁၈eʔҁΌၾᆽ֛f
140ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ ڝྡ1 ༟ৃʔ࿁၈ɨᗇՎҳ༟ɛৃࢹбᒄ҅ ॆྼᄆЗۨ࿒ ˴ɢ I ҳ༟Бމ ˒ U ҳ༟Бމ I జཇ U జཇ IIUUIUUPcV(R,λ,λ)cV(R,λ,λ)λ BbHBbHBbb U IIUUIUIPcV(R,λ,λ)cV(R,λ,λ)λ BsHBsHBsBU λ s I IIUUIUUPcV(R,λ,λ)cV(R,λ,λ)λ SbHSbHSbIbλ SR H UIIUUIU PcV(R,λ,λ)cV(R,λ,λ)SsHssHssU ℚ λ s N ℚ IIUUIU UPcV(R,λ,λ)cV(R,λ,λ)BbLBbLBbλ b R L IIUUIUIUPcV(R,λ,λ)cV(R,λ,λ)λ UBsLBsLBsBλ s I UIIUUIUλ PcV(R,λ,λ)cV(R,λ,λ)bSbLSbLSb Iλ SU IIUUIUUPcV(R,λ,λ)cV(R,λ,λ)SsLssLss λ s (a) ʔ࿁၈jண˴ɢI࿁ᅺٙᗇՎኹϞᜳஷٙ(informed)ӷϞৃࢹprivate informationd͵у࿁ᅺٙᗇՎٙॆྼᄆЗۨ࿒̂ʱə༆fШ˒Uۆ࿁ᅺٙᗇՎٙॆྼᄆЗۨ࿒ʔə༆d͵уऊࢹʔᜳஷ(uninformed)dΪϤᒄ҅ʕՈϞৃࢹʔ࿁၈ٙઋرπίf (b) ʔҁΌj˴natureίᒄ҅ʕӔ֛ᅺٙᗇՎٙ͊Ըॆྼᄆ࠽dՉʕՈϞ৷ॆྼᄆЗۨ࿒higЭॆྼᄆЗۨ࿒(low profit type˴ɢI̙ᝈ࿀ՑdϾ˒Uසۨ࿒̙ٙঐઋرdΪϤᒄ҅ʕ(c) ᆽ ֛j˴ίӔ֛ᅺٙᗇՎуᅺٙᗇՎٙॆྼᄆЗۨ࿒ίh profit typeٙዚଟމ1-ℚiϾՈϞ)ٙዚଟމℚfϤɓॆྼᄆЗۨ࿒̥ϞঐԱ࿁˴ɢٙҳ༟БމкᓙॆྼᄆЗՈϞৃࢹʔҁΌٙତπίf ٙॆྼᄆЗۨ࿒ܝdʔΎϞЪމf͵ᒄ҅කܝکʊӔ֛dʔΎҷᜊdΪ
ࠬᎈ၍ଣኪజ 141ୋɖ՜ ୋɚಂ2005ϋ7˜ Ϥᒄ҅ʕՈϞᆽ֛ٙतЍf c. Бਗཀၾԫj ͉ᒄ҅ʱމɚಂdБਗනҏ݊˴ίୋ 0ಂӔ֛ᅺٙᗇՎٙॆྼᄆЗۨ࿒ܝd͟ᜳஷऊࢹٙ˴ɢIБਗd˸൯ɝᄣٰ̋ܵאር̈ಯˇٰܵᅺٙᗇՎމБਗഄଫiʘܝ˒Uᝈ࿀˴ɢٙҳ༟БމܝΎӔ֛˼ٙҳ༟Бਗfண͉ᒄ҅މɓࣖଟ̹ఙd˲ೌʹהd͵уίୋɚಂഐҼd˴ɢၾ˒ޫʊҁϓҳ༟БމܝdৃࢹҁΌ౧ᚣίٰᄆɪfধʱࠑνɨj (a) ୋ 0 ಂj ίᒄ҅ɓකdᅺٰٙୃᄆࣸމPdԨ͟˴Ӕ֛ᅺٙᗇՎٙ͊0Ըॆྼᄆ࠽dՉʕj H (high profit type)jዚଟމ 1-ℚ L (low profit type) jዚଟމ ℚ ϤࣛdᅺٰٙୃᄆࣸމPf͟ৃࢹʔ࿁၈ʿʔҁΌٙतdɪࠑ༟ৃ̥0Ϟ˴ɢI̙ᝈ࿀ՑdԨٝОࣛᏐʚᐏлəഐd݂ॆྼᄆЗۨ࿒ᒱމԫۃ(ex ante)d͉˖ணၾԫܝ(ex post )ॆྼᄆЗۨ࿒ΝiϾ˒UසঐԱ࿁ᜳஷऊࢹٙҳ༟٫ٙҳ༟БމкᓙॆྼᄆЗۨ࿒̙ٙঐʱбઋرfΪމ༧БމၾՉה༟ৃீܓϞᗫފρd2002iϪ҃ኊd2002dΪϤ˒ኽהᝈ࿀Ցٙ˴ɢ൯ርБމהீᚣʘ༟ৃਂމҳ༟ਞϽf͵у˴ɢ൯ርٰୃٙБމکΝࣛᙑ׳̈࿁ᅺٙᄆࣸ৷ЭجٙৃࢹfϾ˒ҳ༟ɛኹϞʮකৃࢹۍೌ̂΅ӷϞৃࢹdᝈ࿀Ԩ˴ɢҳ༟Бމהᙑ׳ٙϞ͜ৃࢹdΪϤʑึପ͛༧Бމjf (b) ୋ 1ಂj ί˴ɢIᝈ࿀ՑᅂᚤᅺٙᗇՎॆྼᄆЗٙॆྼۨ࿒֠͊౧ᚣʘৃࢹۃdӔ֛મ՟ɚ၇̙ঐٙҳ༟Бމjɓމ൯ɝᅺٰٙୃdᄣٰ̋ܵˢԷIIλ>0dאር̈ᅺٰٙୃdಯˇٰܵˢԷλ>0f BS(c) ୋ 2ಂj ˒ᝈ࿀˴ɢٙҳ༟БމၾٰܵˢԷৃࢹܝd̙ঐમ՟ɚ၇ҳ༟БUਗjɓމ൯ɝᅺٰٙୃdᄣٰ̋ܵˢԷλ>0dאር̈ᅺٰٙୃdಯˇܵbUٰˢԷλ>0Շ၇፯f s(d) ୋ 2 ಂഐҼܝj ίᅺٙᗇՎٙॆྼᄆЗۨ࿒ʘৃࢹʮකdৃࢹҁΌ౧ᚣ̈ԸdॆྼᄆЗˀᏐίٰᄆɪd৷ॆྼᄆЗۨ࿒ॆྼᄆЗމRiЭॆྼᄆЗۨ࿒ॆྼHᄆЗމRf˴ɢၾ˒ٙҳ༟ϗूྼତd͉ᒄ҅ഐҼf Lʔሞٰᄆ݊щ৷Эᅺٰٙୃʘॆྼᄆ࠽d̥ࠅϞᐏлዚึd˴
142ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ ɢޫϞ̙ঐආБҳ༟БމfΪϤdίୋɓಂʕd˴ɢ̙ঐ݊ᎰᎰආאᎰᎰ̈dϤٰࣛᄆʱйމPၾPfίୋɚಂd˒ᝈ࿀Ց˴ɢٙҳ༟БBSމd̙ঐમ՟൯ආር̈БމdϞ̬၇̙ঐj Pc ˒ᝈ࿀Ց˴ɢ൯ආৃࢹܝમ՟൯ආБމdٰᄆމi BbPd ˒ᝈ࿀Ց˴ɢ൯ආৃࢹܝમ՟ር̈Бމdٰᄆމi BsPe ˒ᝈ࿀Ց˴ɢር̈ৃࢹܝમ՟൯ආБމdٰᄆމi SbPf ˒ᝈ࿀Ց˴ɢር̈ৃࢹܝમ՟ር̈Бމdٰᄆމi SsԱDaniel, Hirshleifer & Subrahmanyam (1998) ٙӺdΪҳ༟ɛୌΥБމଣሞbehavior theoryၾІҢतሯଣሞself-attribution theoryd࿁ϞлІҢٙҳ༟Бމٙৃࢹึˢࡡཫಂһ̋ᆀᝈiˀʘd࿁ʔлІҢҳ༟Бމٙৃࢹึ༰ڭςfΪϤdˀᏐίٰᄆɪяତ൯ርᆵ࿁൯ርᆵпပൻ͵уP>PiP>PdШˀʘɢ༸༰ʔԑdΪϤdҢࡁਗ਼BbBSSsɪࠑٰᄆԱ˸ɨනҏરΐdᏐ᙮ΥଣjKhanna & Sonti, 2000 R≥P>P>P>P>P>P>P≥R(1) HBbBBs0SbSSsLd. ̙ঐٙഄଫଡ଼Υj ͟ᅺٙᗇՎٙॆྼᄆЗۨ࿒Ϟɚ၇jH א Li I ̙ٙঐҳ༟БਗϞɚ၇jB א Si U ̙ٙঐҳ༟БਗϞɚ၇jb א si ΪϤ͉ᒄ̙҅ٙঐٙഄଫଡ଼ΥϞ8 ၇f 3. ᒄ҅ᅼό ίආБ͉ᒄ҅ٙѩፅ༆ٙʱؓۃdႭਿ͉ணνɨj ᗇՎ̹ఙʕ̙ҳ༟ᗇՎᅰͦεdҳ༟٫މᅰɰεd͉ᒄ҅މəᔊʷ࿁ᗇՎ̹ఙ༧ҳ༟Бމٙઞীdண̥ϞɓЗኹϞᜳஷऊࢹٙ˴ɢʿɓ˙ʔՈϞᜳஷऊࢹٙΝሯ˒fᅼۨᒱ̥ڻࠢఊɓᅺٙᗇՎdഐ؈Ꮠ༈̙˸ቇ͜ίՉ̴ᅺٙᗇՎɪf IIணίୋtಂd˴ɢ(I)ၾ˒(U)ٙৌబଡ଼Υʱйމ(W,α)ၾttUU(W,α)dW˾ڌତږdα˾ڌהٰܵᅰЦᅺٰٙୃݴஷίٰ̮ᅰٙˢttIUԷfணVၾVʱй˾ڌɚ٫ٙజᎵՌᅰpayoff functiondԱྡ1ٙᒄ҅ഐdίୋɚಂഐҼࣛdϞɞ၇ഄଫଡ଼ΥజᎵՌᅰf˸ɨਗ਼ୋɓ၇ഄଫБਗଡ଼ΥЪႭdાࠑ˴ɢٙజᎵՌᅰj ίᒄ҅ʘڋୋ0ಂd˴Ӕ֛ᅺٰٙୃٙॆྼᄆЗۨ࿒މ৷лᆗ
ࠬᎈ၍ଣኪజ 143ୋɖ՜ ୋɚಂ2005ϋ7˜ (H)dШ̥ϞኹϞᜳஷৃࢹٙ˴ɢٝfίୋɓ၇ഄଫБਗɨd˴ɢίୋIɓಂ൯ආٰୃdԨбٰܵˢԷᄣ̋λٙৃࢹdίୋɓಂഐҼࣛd˴ɢٙBᐼତږπඎމj IIIW=W−λP(2) 10BBՉʕ IIIλ=α−α(3)B10IIՉʕୋɓಂٙʹᄆࣸމPdαeαʱй˾ڌ˴ɢίୋ0ಂၾୋ1ಂܵB01Iٰᅰඎα≥ 0f 0ίୋɚಂd˒ᝈ࿀Ց˴ɢᄣٰ̋ܵٙৃࢹܝdમ՟൯ආٙҳ༟ഄଫdUUλண൯ආᅰඎމλdʹᄆࣸމPdΝࣛڌͪ˴ɢር̈ᅰඎ͵މdΪϤd bbBbIIUα=α−λ(4)21bʹࠢՓόމj IIIIW+αP=W+αP11Bb22BbIIII אW=W+(α−α)P (4a)2112BbIU=W+λP1bBbୋɚಂഐҼd˴ɢٙৌబމj IIIUIW+αR=W+λP+αR22H1bBb2HIUIU=W+λP+(α−λ)R (5) 1bBb1bHIIU=W+αR+(P−R)λ11HBbHb(3)ό˾ɝ(5)όj IIIIIIUW+αR=W+αP−αP+αR−λ(R−P)22H00B1B1HbHBb (5a) IIIU=W+αP+α(R−P)−λ(R−P)00B1HBbHBb˴ɢٙҳ༟ഄଫజᎵՌᅰމj IIUIIIIV(R,λ,λ)=(W+αR)−(W+αP)HBb22H00B (6) IU=α(R−P)−λ(R−P)1HBbHBb
144ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ Ա(2)Ї(6)όٙપኬ˙όdҢࡁ̙˸પኬ̈Չ˼ɖ၇ഄଫజᎵՌᅰdԨคᐼνڌ1הͪf ڌ1 ᒄ҅ʘ˴ɢၾ˒ҳ༟ഄଫజᎵՌᅰ ഄଫ ˴ɢజᎵՌᅰ˒జᎵՌᅰ ۨ࿒ IIUIUUIUIUI V(R,λ,λ)=α(R−P)−λ(R−P)V(R,λ,λ)=−α(R−P)+λ(R−P)HBb1HBbHBbHBb1HBbHBbIIUIUUIUIUII V(R,λ,λ)=α(R−P)+λ(R−P)V(R,λ,λ)=−α(R−P)−λ(R−P)HBs1HBsHBsHBs1HBsHBsIIUIUUIUIUIII V(R,λ,λ)=α(R−P)−λ(R−P)V(R,λ,λ)=−α(R−P)+λ(R−P)HSb1HSbHSbHSb1HSbHSbIIUIUUIUIUIV V(R,λ,λ)=α(R−P)+λ(R−P)V(R,λ,λ)=−α(R−P)−λ(R−P)HSs1HSsHSsHSs1HSsHSsIIUIUUIUIUV V(R,λ,λ)=−α(P−R)+λ(P−R)V(R,λ,λ)=α(P−R)−λ(P−R)LBb1BLbBbLLBb1BLbBbLIIUIUUIUIUVI V(R,λ,λ)=−α(P−R)−λ(P−R)V(R,λ,λ)=α(P−R)+λ(P−R)LBs1BLsBsLLBs1BLsBsLIIUIUUIUIUVI I V(R,λ,λ)=−α(P−R)+λ(P−R)V(R,λ,λ)=α(P−R)−λ(P−R)LSb1SLbSbLLSb1SLbSbLIIUIUUIUIUVI II V(R,λ,λ)=−α(P−R)−λ(P−R)V(R,λ,λ)=α(P−R)+λ(P−R)LSs1SLsSsLLSs1SLsSsL 4. ѩፅʱؓ ͉Ӻમ͜ҁߕԎˤѩፅᝈᓃdరҬৃࢹбᒄ҅ᅼόٙѩፅ༆fတIUԑɨΐɧࡈૢٙഄଫଡ଼Υ(λ(.),λ(.))ၾజཇՌᅰʘૢڦׂπ..٫၈ʘމҁߕԎˤѩፅj (1) ࿁˴ɢהбٙ၇ৃࢹd˒͟הᝈ࿀Ցٙৃࢹʿ࿁Ϥৃࢹٙu*ڦׂd՟ԴՉಂૐజᎵމ௰ɽٙБਗމഄଫdΪϤ߰λމ˒ٙ௰U*IԳБਗdۆλ(λ)Ꮠ݊ɨόٙ௰Գ༆j UIUIMaxV(R,λ,λ)πRλ∑iii=H,L uλ(2) ˴ɢٙഄଫd̀݊˸˒ٙڦׂʿ௰ԳБਗމۃɨٙ௰ԳഄI*I*λλଫdה˸߰މ˴ɢٙ௰Գഄଫdۆމɨόٙ௰Գ༆j IIU*MaxV(R,λ,λ) Iλ
ࠬᎈ၍ଣኪజ 145ୋɖ՜ ୋɚಂ2005ϋ7˜ II(3) ࿁הϞλdૢዚଟπ.λڷ͟జᎵۨ࿒Rٙዚଟʿ֛݅RૢI3ɨٙ฿ׂዚଟπα.ԱԎˤجۆࡌ͍ϾfΪϤdίҁߕԎˤѩፅً࿒ɨd˒ٙБਗڷ͟הᝈ࿀˴ɢҳ༟Бމהᙑ׳ٙৃࢹԱڦׂкᓙהЪϓٙ፯i˴ɢٙഄଫ͵݊ίϽᅇཀ˒ٙˀᏐܝהЪϓٙdה༺ϓٙҁߕԎˤѩፅd݊ɓ၇ᖢ֛ٙѩፅf˸ɨধ̬ܲ၇ఊॱഄଫpure strategyઞী̙ঐπίٙѩፅ༆f RбλৃࢹdRбλৃࢹٙʱᕎѩፅʱؓ HBLSa. ˒ٙБਗ፯ Iί͊ԸٙॆྼᄆЗɪʺٙઋرɨd˴ɢ̙˸፯ٰܵˢԷᄣ̋λбBIεৃࢹd˸ႰԴ˒༧ආd͵̙፯ٰܵˢԷಯˇλб٤ৃࢹd˸SᏀЭᄆࣸΎіiί͉ԸॆྼᄆЗɨࠥٙઋرɨd˴ɢ̙˸፯ٰܵˢԷIIᄣ̋λбεৃࢹd˸ႰԴ˒൯ආϾથུՉ̈dא፯ಯˇλBSIIб٤ৃࢹd˸ႰԴ˒ር̈dுЭΎආfࠦ࿁̙ঐٙαၾαৃࢹdBS˒Ԩʔٝ༸͊ԸॆྼᄆЗᜊʷٙ˙ΣdΪϤ̥ঐԱኽཀ᜕̘הҖϓٙIIڦׂЪкᓙfίRбλৃࢹdRбλৃࢹٙʱᕎόѩፅઋرɨdHBLSIII˒ٙڦׂ݊πRλ=1dπRλ=1dу࿁λৃࢹٙڦׂމ͊ԸॆྼHBLSBIIᄆЗމRd࿁λৃࢹٙڦׂމ͊ԸॆྼᄆЗމRfί˒ᝈ࿀ՑλৃࢹHSLBܝdԱڦׂ˒ਗ਼Ⴉމ͊ԸॆྼᄆЗމRdϾίˢ༰H0IU0IUV(R,λ,λ)ၾV(R,λ,λ)ܝ՟БਗfԱ(2)Ї(6)όٙપଣཀdҢࡁHBbHBs̙ᐏj UIUIUV(R,λ,λ)=−α(R−P)+λ(R−P) (7) HBb1HBbHBbUIUIUV(R,λ,λ)=−α(R−P)+λ(R−P) (8) HBs1HBsHBs (7)ό-(8)ό̙j UUλ(R−P)+λ(R−P)>0 (9)bHBbsHBsIUΪϤd˒࿁˴ɢбλৃࢹٙ௰Գഄଫމλf Bb I3 ˒Ա˴ɢʘҳ༟Бމࡌ͍࿁ᅺٰٙᄆ࠽ٙ˴ᝈڦׂd͵уԱԎˤ֛ଣਗ਼ԫܝዚଟπα.ࡌ͍މԫۃዚIଟπ.λf
146ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ IΝଣd˒ίᝈ࿀Ց˴ɢλৃࢹܝٙڦׂd݊͊ԸॆྼᄆЗਗ਼ɨࠥՑSUIUUIURdΪϾՉ௰ԳБਗ݊ίˢ༰V(R,λ,λ)ၾV(R,λ,λ)ܝЪϓٙfLLSbLSsԱ(2)Ї(6)όΝᅵપଣdҢࡁ̙ᐏj UIUIUV(R,λ,λ)=α(P−R)+λ(P−R) (10) LBb1SLbSbLUIUIUV(R,λ,λ)=−α(R−P)+λ(R−P) (11) HBs1HBsHBs(11)όÑ(10)ό̙j UUλ(P−R)+λ(P−R)>0(12)sSsLbSbL IUΪϤd˒࿁˴ɢбλৃࢹٙ௰Գഄଫމλf SsIb. ˴ɢٙഄଫ൙Пλ SR(i) ͊ԸٙॆྼЗމࣛ HIUλ߰˴ɢбৃࢹd˒ԱڦׂהٙБਗਗ਼݊λdϤࣛ˴ɢٙజBbIIUIUᎵމV(R,λ,λ)i߰˴ɢбλৃࢹd˒࿁Ϥৃࢹٙ௰ԳБਗ݊λdHBbSsIIIUλ˴ɢٙజᎵމV(R,λ,λ)fΪϤdί͊ԸٙॆྼᄆЗމRࣛd߰݊BHSsH˴ɢٙ௰Գഄଫdۆცတԑj IIUIIUV(R,λ,λ)>V(R,λ,λ) (13) HBbHSsૢfԱ(3)Ї(6)όપଣ˙όdҢࡁ̙ᐏj IIUIUV(R,λ,λ)=α(R−P)+λ(R−P)(14) HSs1HSsHSsIIUIUV(R,λ,λ)=α(R−P)−λ(R−P) (6)HBb1HBbHBbIλ߰މ˴ɢٙ௰Գഄଫd̀တԑ(6)ό-(14)ό>0d BIUU(6)ό-(14)ό=−α(P−P)−λ(R−P)−λ(R−P) 1BSbHBbsHSsIUU =−[α(P−P)+λ(R−P)+λ(R−P)]<0 (15) 1BSbHBbsHSsIΪϤdᅺٰٙୃٙॆྼᄆЗމHࣛdλԨڢ˴ɢٙ௰Գҳ༟ഄଫf B(ii) ͊ԸٙॆྼᄆЗމRࣛ LIΝଣdί͊ԸॆྼᄆЗމRࣛd߰λ݊˴ɢٙ௰ԳഄଫdۆတԑLSIIUIIUV(R,λ,λ)>V(R,λ,λ)ૢfԱ(3)Ї(6)όપଣ˙όdҢࡁ̙j LSsLBb
ࠬᎈ၍ଣኪజ 147ୋɖ՜ ୋɚಂ2005ϋ7˜ IIUIUV(R,λ,λ)=−α(P−R)−λ(P−R)(16)LSs1SLsSsLIIUIUIV(R,λ,λ)=−α(P−R)+λ(P−R)λ (17) LBb1BLbBbLS߰މ˴ɢٙ௰Գഄଫd̀တԑ(16)ό-(17)ό>0d (16)ό-(17)ό IUUα(P−P)−λ(P−R)−λ(P−R)(18) = 1BSsSsLbBbLIλ݂މ˴ɢٙ௰Գഄଫ̀ୌΥ˸ɨૢj SUUλ(P−R)+λ(P−R)IsSsLbBbLα> (18a) 1P−PBS(iii) ʱᕎόѩፅٙૢ II(15)όၾ(18)όΝࣛϓͭމတԑRбλৃࢹeRбλৃࢹٙૢHBLSfҢࡁਗ਼(15)όၾ(18)ό̙̋j UU−(λ+λ)(R−R)<0(19)(15)ό+(18)ό= bsHLIRλRΪމ(19)όܩމࠋ࠽ઋرɨd̙˸ə༆dίбৃࢹeίHBLIбλৃࢹdԨڢ˴ɢΪᏐ˒Бਗٙ௰ԳഄଫfϤɓʱᕎ༆ѩፅԨʔπίf RбλৃࢹdRбλৃࢹٙʱᕎόѩፅʱؓ HSLBa. ˒ٙഄଫ൙П IIίRбλৃࢹdRбλৃࢹٙઋرɨd˒ٙڦׂ݊HSLBIIUIUUIUπRλ=1dπRλ=1fˢ༰V(R,λ,λ)ၾV(R,λ,λ)̙˸ᐏHSLBLBbLBsIIٝ˒ίࠦ࿁λၾλৃࢹࣛdהᏐમ՟ٙБਗfԱ(3)Ї(6)όٙપଣd̙BSj UIUIUV(R,λ,λ)=−α(R−P)+λ(R−P)(20) HSb1HSbHSbUIUIUV(R,λ,λ)=−α(R−P)−λ(R−P)(21) HSs1HSsHSsUU(20)ό-(21)ό=λ(R−P)+λ(R−P)>0(22) bHSbsHSsIUΪϤd˒࿁˴ɢбλৃࢹٙ௰Գഄଫމλf̤̮dԱ(2)Ї(6)όdSb̙˸ᐏj
148ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ UIUIUV(R,λ,λ)=α(P−R)+λ(P−R) (23) LBs1BLSBsLUIUIUV(R,λ,λ)=α(P−R)−λ(P−R) (24) LBb1BLbBbLUU(23)ό-(24)ό=λ(P−R)+λ(P−R)>0 (25) bBbLsBsLIUΪϤd˒࿁˴ɢбλৃࢹٙ௰Գഄଫމλf Bsb. ˴ɢٙഄଫ൙П (i) ͊ԸॆྼᄆЗމRࣛ HIRRλԱۃ˖ʘપଣᝈׂd͊ԸॆྼᄆЗމࣛd߰૧ίɨбৃHHSࢹމ˴ɢٙ௰Գഄଫࣛdۆတԑj IIUIIUV(R,λ,λ)V(R,λ,λ)> (26) HSbHBsԱ(2)Ї(6)ό̙ IIUIUV(R,λ,λ)=α(R−P)−λ(R−P) (27) HSb1HSbHSbIIUIUV(R,λ,λ)=α(R−P)+λ(R−P)(28)HBs1HBsHBsIUU(27)ό-(28)ό=α(P−P)−λ(R−P)−λ(R−P) (29) 1BSbHSbsHBsIλ݂މ˴ɢ௰Գഄଫ̀ୌΥ˸ɨૢj SUUλ(R−P)+λ(R−P)IbHSbsHBsα> (29a) 1P−PBS(ii) ͊ԸॆྼᄆЗމRࣛ LIRλΝଣdί͊ԸॆྼᄆЗމࣛd˴ɢбމ௰Գdۆတԑ LBIIUIIUV(R,λ,λ)V(R,λ,λ)>(30)LBsLSbԱ(2)όЇ(6)ό̙ IIUIUV(R,λ,λ)=−α(P−R)−λ(P−R)(31) LBs1BLsBsLIIUIUV(R,λ,λ)=−α(P−R)+λ(P−R)(32) LSb1SLbSbLIUU(31)ό-(32)ό=−[α(P−P)+λ(P−R)+λ(P−R)]<0 (33) 1BSsBsLbSbL
ࠬᎈ၍ଣኪజ 149ୋɖ՜ ୋɚಂ2005ϋ7˜ IλRΪϤdԨڢίʘɨd˴ɢٙ௰Գҳ༟ഄଫf BLc. ʱᕎόѩፅૢ IIR(29)όၾ(33)όΝࣛϓͭމတԑRбλৃࢹeбλৃࢹٙૢLHSBfҢࡁਗ਼(29)όၾ(33)ό̙̋j UU−(λ+λ)(R−R)<0(34)(29)ό+(33)ό= bsHLII͟(34)όܩމࠋ࠽ઋرɨd̙˸ə༆dίRбλৃࢹdίRбλHSLBৃԨڢ˴ɢΪᏐ˒Бਗٙ௰ԳഄଫdϤɓʱᕎ༆ѩፅԨʔπίf Iλ ৃࢹ૿ଌόѩፅʱؓ Ba. ˒ٙБਗ፯ Iίλৃࢹ૿ଌɨdʔሞ͊ԸॆྼᄆЗٙᜊʷ݊ɪʺRאɨࠥBHIRd˴ɢே̥бλৃࢹfΪϤd˒̥͟ڦׂዚଟ࠽Ըкᓙ̙ঐLBIIًٙرdϤࣛ˒ٙڦׂމπRλ=1−qdπRλ=qfԱኽڦׂdHBLBUUU˒ˢ༰મλၾλБਗٙಂૐజᎵܝdΎЪϓБਗ፯d߰˒મλБbsb4މdۆՉಂૐజᎵމjUIUUIU(1−q)V(R,λ,λ)+qV(R,λ,λ) (35) HBbLBbԱ(7)όၾ(24)όd̙˸ଣ(35)όνɨj IU(35)ό=(1−q)[−α(R−P)+λ(R−P)] 1HBbHBbIU +qα(P−R)−λ(P−R) 1BLbBbLIUIU =q(α−λ)(R−R)−α(R−P)+λ(R−P) (35a) 1bHL1HBbHBbUλ̤̮d߰મБਗʘಂૐజᎵމj sUIUUIU(1−q)V(R,λ,λ)+qV(R,λ,λ) (36) HBsLBsԱ(8)όၾ(23)όd̙˸ଣ(36)όνɨj 4 qމ˒Աהϗණ༟ৃהᐏٙૢዚ率dމɓܝ˂ዚ率fၾᒄ҅ഐ3ʘ(1)ʕהࠑʘℚ不Νdܝ٫މ˴࿁ᅺٙᗇՎॆྼᄆ࠽৷Эʘ᜕ዚ率f
150ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ IU(36)ό=(−q)[−α(R−P)−λ(R−P)]1HBsHBsIU +qα(P−R)+λ(P−R) 1BLsBsLIUIU =q(α+λ)(R−R)−α(R−P)−λ(R−P) (36a) 1sHL1HBsHBsIUίλ૿ଌόѩፅʘɨd˒௰Գҳ༟ഄଫணމλdۆ̀(35a)όBb>(36a)όd͵у(35a)ό-(36a)ό>0i (35a)ό-(36a)ό= UUUU −q(λ+λ)(R−R)+λ(R−P)+λ(R−P)>0d bsHLbHBbsHBŝ΅ૢމj UUλ(R−P)+λ(R−P)bHBbsHBsq<=q (37) bUU(λ+λ)(R−R)bsHL͟(1)όʕP>Pٙᗫڷ̙ٝj BbBsUUUUλ(R−P)+λ(R−P)λ(R−P)+λ(R−P)bHBbsHBsbHBssHBsq<q=<bUUUU(λ+λ)(R−R)(λ+λ)(R−R)bsHLbsHL UU(λ+λ)(R−P)R−PbsHBsHBs==<1UU(λ+λ)(R−R)R−RbsHLHLUqqΪϤd݊πίٙd౬Ԋʘd̥Ϟίq࠽ʃࣛdλʑ݊˒ٙ௰bbbԳҳ༟ഄଫfՉʕR࿁ᅺٰٙୃᄆ࠽৷ᓃಂૐฏɽq࠽ฏɽi̤̮ίHbR-Rո֛ɨdPP࠽ฏʃdՑᅺٰٙୃᄆ࠽৷ᓃʘ൷ᕎฏჃdq࠽HLBsBbbqฏɽdۆq࠽ʃ̙ٙঐఱฏ৷f bb. ˴ɢٙഄଫ൙П (i) ί͊ԸٙॆྼᄆЗɪʺRઋرࣛ HIIUλλৃࢹ૿ଌࣛdίq<qࣛd˒ٙ௰ԳБਗ݊λfΪϤd߰૧BBBb݊௰Գഄଫdۆတԑɨόૢj IIUIIUV(R,λ,λ)>V(R,λ,λ) (38)HBbHSb͟(6)όၾ(27)όdɪΐʔഃόމj
ࠬᎈ၍ଣኪజ 151ୋɖ՜ ୋɚಂ2005ϋ7˜ IUIUα(R−P)−λ(R−P)>−α(R−P)−λ(R−P) (39) 1HBbHBb1HSbHSbଣj UIλ(P−P)>α(P−P)d͵у bBbSb1BSIα(P−P)U1BSλ>>0 (39a) bP−PBbSbI(39a)όϓͭࣛdλމ˴ɢٙ௰Գҳ༟ഄଫf B(ii) ί͊ԸٙॆྼᄆЗɨࠥRઋرࣛ LIΝଣdί͊ԸॆྼᄆЗɨࠥࣛd૧λ݊௰Գഄଫdۆတԑj BIIUIIUV(R,λ,λ)>V(R,λ,λ)(40)LBbLSb͟(17)όၾ(32)όdɪΐʔഃόމj IUIU −α(P−R)+λ(P−R)>−α(P−R)+λ(P−R) (41) 1BLbBbL1SLbSbLଣj UIλ(P−P)>α(P−P)d͵уΝ(39a)όj bBbSb1BSIα(P−P)U1BSλ>>0(41a)bP−PBbSbc. Ԏˤجۆࡌ͍ IIIλৃࢹ૿ଌόѩፅٙૢዚଟމπλR=1dπλR=0d BBHSHIIπλR=0dπλR=1dৣΥπ(R)=1−ℚdπ(R)=ℚ˾ɝԎόSLBLHLجۆʮόd̙˸ᐏj IπλRπ(R)BHHIπRλ== ℚHBIIπλRπ(R)+πλRπ(R)BHHBLL (42) IπλRπ(R)BLLIπRλ==ℚ LBIIπλRπ(R)+πλRπ(R)BHHBLLIίλৃࢹ૿ଌɨdʔሞ͊ԸॆྼᄆЗٙᜊʷ݊ɪʺRאɨࠥBHIRd˴ɢே̥бλৃࢹd˒͟ڦׂዚଟ࠽Ըкᓙ̙ঐًٙرdLBIIཀԎˤ֛ଣࡌ͍ܝd˒ٙܝ˂ڦׂπRλ=1−qdπRλ=qၾ˴HBLB
152ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ Iλٙ˂ዚଟΝfΪϤd˒ίৃࢹ૿ଌɨٙ˴ᝈڦׂୌΥԎˤجۆBIλࡌ͍dৃࢹ૿ଌѩፅމҁߕԎˤѩፅfΪ˸ɪપሞdҢࡁ̙˸ᓥॶ̈νBɨնᕚj IλնᕚŎjίৃࢹ૿ଌɨd߰˒Ⴉމ͊ԸॆྼᄆЗਗ਼ɨࠥٙڦׂ࠽qʃBqމʃ1͍ٙᅰԨ˲˴ɢႩމ͊ԸॆྼᄆЗਗ਼ɨࠥࣛdb߰j Iα(P−P)U1BS λ>>0 bP−PBbSbIۆπίഹλৃࢹ૿ଌόҁߕԎˤѩፅً࿒f Bd. ѩፅٙจ Iίλৃࢹ૿ଌόѩፅً࿒ɨd˒ೌج͟˴ɢהбٙৃࢹdᐏBᆽٙڦׂdΪϤڦׂ࠽̥ঐ˸ዚଟ࠽৷Эڌͪf˒Ⴉމᅺٰٙୃ͊Ըॆྼᄆ࠽̙ঐɨࠥٙዚଟ࠽৷ݔɓᅰ(q)ࣛd͟ॆྼᄆЗɨ̙ࠥٙbঐܘ৷d˒್ʔึჀڦ˴ɢהбٰٙܵˢԷᄣ̋ৃࢹdΪϾ5IʔึաႰ̋ɝᒄ҅dίϤઋرɨdλৃࢹ૿ଌѩፅʔึπίf BIλ૿ଌόѩፅً࿒πί̤ٙɓࡈૢ݊j BIα(P−P)U1BSIλ>≥α b1P−PBbSbՉจމj (q)(1) ˒Ⴉމ͊Ըॆྼᄆ࠽̙ঐމЭٙዚଟ࠽ʃݔɓᅰ࠽ࣛdb˒ᗴจ༧ᎇ˴ɢආБ൯ආҳ༟ഄଫdϾ˲൯ආٰᅰ৷ݔɓᅰඎIλʘɨdʑঐᆽڭ˴ɢٙజᎵ൴ཀбdϾ˒મ՟൯ආഄଫSٙజᎵf I(2) ˴ɢбλٙ૿ଌৃࢹdѩፅٙૢνɪהࠑdɚධૢѩ՟ӔB˒fୋɓධ݊˒Ⴉމॆྼᄆ࠽މЭ̙ٙঐʔ৷dᗴจમ༧ආ൯ɝഄଫfୋɚධ݊ᗴจ൯ආᅰඎɽdЇˇ൴ཀ˴ɢࡡԸٰٙܵIˢԷ(α)ʘɪfۃ٫މ˴ᝈૢdܝ٫މ܄ᝈૢfΪϤd˴ɢה1бٙ૿ଌৃࢹ݊щঐϓͭd༺ϓཫПٙజᎵ˥dʥϞܙ˒ٙৣΥϾ֛f λৃࢹ૿ଌόѩፅʱؓ S 5 qމɓ˴ᝈٙڦׂdၾҳ༟ɛٙࠬᎈ࿒ܓϞᗫfҳ༟ɛฏᒈΣڭςࣛR-RฏʃאPeP࠽ฏɽdqᏐbHLBsBbb༈ฏʃf
ࠬᎈ၍ଣኪజ 153ୋɖ՜ ୋɚಂ2005ϋ7˜ a. ˒ٙБਗ፯ IλRίৃࢹ૿ଌɨdʔሞ͊ԸॆྼᄆЗٙᜊʷ݊ɪʺאɨࠥSHIRλd˴ɢே̥бৃࢹfΪϤd˒̥͟ڦׂዚଟ࠽Ըкᓙ̙ঐLSIIًٙرdϤࣛ˒ٙڦׂމπRλ=1−qdπRλ=qfԱኽڦׂdHSLSUUUλλ˒ˢ༰મλၾБਗٙಂૐజᎵܝdΎЪϓБਗ፯d߰˒મБsbbމdۆՉಂૐజᎵމj UIUUIU(1−q)V(R,λ,λ)+qV(R,λ,λ) (43) HSbLSbԱ(10)όၾ(20)όd̙˸ଣ(43)όνɨj IU(43)ό=(−q)[−α(R−P)+λ(R−P)]1HSbHSbIU +qα(P−R)−λ(P−R) 1SLbSbLIUIU=q(α−λ)(R−R)−α(R−P)+λ(R−P) (43a) 1bHL1HSbHSbṲ̮d߰મλБਗʘಂૐజᎵމj sUIUUIU(1−q)V(R,λ,λ)+qV(R,λ,λ) (44) HSsLSbԱ(11)όၾ(21)όd̙˸ଣ(44)όνɨj IU(44)ό=(−q)[−α(R−P)−λ(R−P)]1HSsHSsIU +qα(P−R)+λ(P−R) 1SLsSsLIUIU =q(α+λ)(R−R)−α(R−P)−λ(R−P) (44a) 1sHL1HSsHSsUIλίλ૿ଌόѩፅʘɨd˒௰Գҳ༟ഄଫணމdۆ̀(44a)όsS>(43a)όd͵у(44a)ό-(43a)ό>0i (44a)ό-(43a)ό= UUUUq(λ+λ)(R−R)−λ(R−P)−λ(R−P)>0 (45) bsHLbHSbsHSsUUλ(R−P)+λ(R−P)bHSbsHSsq>=q>0 (45a) sUU(λ+λ)(R−R)bsHL͟(1)όʕP>Pٙᗫڷ̙ٝj SbSs
154ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ UUUUλ(R−P)+λ(R−P)λ(R−P)+λ(R−P)bHSbsHSsbHSbsHSbq=>sUUUU(λ+λ)(R−R)(λ+λ)(R−R)bsHLbsHL UU(λ+λ)(R−P)R−PbsHSbHSb==<1UU(λ+λ)(R−R)R−RbsHLHLUqqΪϤd݊πίٙd౬Ԋʘd̥Ϟίq࠽ɽࣛdλʑ݊˒ٙ௰sssԳҳ༟ഄଫfՉʕR࿁ᅺٰٙୃᄆ࠽Эᓃಂૐ࠽ฏʃq࠽ฏʃi̤̮LsίR-Rո֛ɨdPP࠽ฏʃdՑᅺٰٙୃᄆ࠽Эᓃʘ൷ᕎฏڐdq࠽H LSsSbsฏʃdۆq࠽ʃq̙ٙঐఱฏ৷f sb. ˴ɢٙഄଫ൙П R(i) ί͊ԸٙॆྼᄆЗɪʺઋرࣛ HIUIλৃࢹ૿ଌࣛdίq<qࣛd˒ٙ௰ԳБਗ݊λfΪϤd߰૧λSssS݊௰Գഄଫdۆတԑɨόૢj IIUIIUV(R,λ,λ)>V(R,λ,λ) (46)HSsHBs͟(14)όၾ(28)όdɪΐʔഃόމj IUIUλ(R−P)+λ(R−P)>λ(R−P)+λ(R−P) (47) 1HSsHSb1HBsHBsଣj UI λ(P−P)+α(P−P)>0 (47a) sBsSs1BSI͵у(47a)ܩϓͭdމɓᖢ֛ѩፅૢdλމ˴ɢٙ௰Գҳ༟ഄଫf S(ii) ί͊ԸٙॆྼᄆЗɨࠥRઋرࣛ LIΝଣdί͊ԸॆྼᄆЗɨࠥࣛd૧λ݊௰Գഄଫdۆတԑj SIIUIIUV(R,λ,λ)>V(R,λ,λ)(48)LSsLBs͟(16)όၾ(31)όdɪΐʔഃόމj IUIU−α(P−R)−λ(P−R)>−α(P−R)−λ(P−R) (49) 1SLsSbL1BLsBsLଣj UIλ(P−P)+α(P−P)>0 (49a)sBbSs1BSI(49a)όܩϓͭdމɓᖢ֛ѩፅૢdλމ˴ɢٙ௰Գҳ༟ഄଫf Sc. Ԏˤجۆࡌ͍
ࠬᎈ၍ଣኪజ 155ୋɖ՜ ୋɚಂ2005ϋ7˜ IIIλৃࢹ૿ଌόѩፅٙૢዚଟމπλR=0dπλR=1dSBHSHIIπλR=1dπλR=0dৣΥπ(R)=1−ℚdπ(R)=ℚ˾ɝԎόجSLBLHLۆʮόd̙˸ᐏj IπλRπ(R)SHHIπRλ== ℚ HSIIπλRπ(R)+πλRπ(R)SHHSLL (50) IπλRπ(R)SLLIπRλ==ℚLSIIπλRπ(R)+πλRπ(R)BHHBLLIίλৃࢹ૿ଌɨdʔሞ͊ԸॆྼᄆЗٙᜊʷ݊ɪʺRאɨࠥSHIRd˴ɢே̥бλৃࢹd˒͟ڦׂዚଟ࠽Ըкᓙ̙ঐًٙرdLSIIཀԎˤ֛ଣࡌ͍ܝd˒ٙܝ˂ڦׂπRλ=1−qdπRλ=qၾ˴HSLSIٙ˂ዚଟΝfΪϤd˒ίλৃࢹ૿ଌɨٙ˴ᝈڦׂୌΥԎˤجۆSIλࡌ͍dৃࢹ૿ଌѩፅމҁߕԎˤѩፅfԱኽ˸ɪપሞdҢࡁ̙˸ᓥॶ̈Sνɨնᕚj Iնᕚŏjίλৃࢹ૿ଌɨd߰˒Ⴉމ͊ԸॆྼᄆЗਗ਼ɨࠥٙڦׂ࠽qɽSIqމɽ1͍ٙᅰfۆπίഹλৃࢹ૿ଌόҁߕԎˤѩፅsSً࿒f d. ѩፅٙจ Iίλৃࢹ૿ଌόѩፅً࿒ɨd˒ೌج͟˴ɢהбٙৃࢹdϾᐏSᆽٙڦׂdΪϤڦׂ࠽̥ঐ˸ዚଟ࠽৷Эڌͪf˒Ⴉމᅺٰٙୃ͊Ըॆྼᄆ࠽̙ঐɨࠥٙዚଟ࠽Эݔɓᅰ(q)ࣛd͟ॆྼᄆЗɨࠥٙs̙ঐʔ৷d˒್ʔึჀڦ˴ɢהбٰٙܵˢԷಯˇৃࢹdΪIϾʔึաႰ̋ɝᒄ҅dίϤઋرɨdλৃࢹ૿ଌѩፅʔึπίf S5. ᒄ҅Ꮸী ίɪࠑᒄ҅ѩፅʱؓʕdҢࡁᐏɚධ૿ଌόѩፅً࿒dШʔπίОʱᕎόѩፅً࿒fίɚධ૿ଌόѩፅً࿒ʕdν؈˴ɢ̙˸ீཀ൯ආIIርٰ̈ܵdீᚣٰܵˢԷλ(λ)ٙৃࢹd˸ᅂᚤ˒࿁ᒄ҅ٙڦׂdBSۆ˴ɢᏐ༈̙˸ə༆d˒༧ආҳ༟ٙഄଫ͵݊Ӕ֛ᒄ҅ѩፅٙࠠࠅૢ
156ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ fΪϤd˒ɰ̙˸ᕎՉڦׂd፯Չฌٙѩፅً࿒f˸ɨʱй˴ɢၾ˒ٙԉܓʱؓࡈйฌٙѩፅً࿒މОk ˒ฌٙѩፅً࿒ʱؓ ˢ༰ɚධ૿ଌόѩፅً࿒ɨd˒ٙಂૐజཇj Ua. λ૿ଌόѩፅ BIUIU(1−q)[−α(R−P)+λ(R−P)]+q[α(P−R)−λ(P−R)] 1HBbHBb1BLbBbLIUIU=−α(R−P)+λ(R−P)+q(α−λ)(R−R) (51) 1HBbHBb1bHLUb. λ૿ଌόѩፅ SIUIU(1−q)[−α(R−P)−λ(R−P)]+q[α(P−R)+λ(P−R)] 1HSsHSs1SLsSsLIUIU−α(R−P)−λ(R−P)+q(α+λ)(R−R)= (52) 1HSsHSs1sHLˢ༰ɚ٫ٙಂૐజཇd (51)ό-(52)ό= IUUUUα(P−P)+λ(R−P)+λ(R−P)−q(λ+λ)(R−R) (53) 1BSsHSsbHBbsbHL˸ɨૢϓͭࣛd(53)όމ͍j IUUα(P−P)+λ(R−P)+λ(R−P)*1BSsHSsbHBbq<=q (54) bUU(λ+λ)(R−R)sbHLɪόʕdP≈HdP≈Hdۆ BbLSsLIUα(P−P)+λ(R−R)*1BSsHLq≈ (54a) bUU(λ+λ)(R−R)sbHL*Ϊމ(P−P)<(R−R)dqʃ1Ꮠ᙮Υଣf BSHLb*նᕚŐjί˒࿁͊ԸٰୃॆྼᄆЗɨൻ̙ٙঐٙڦׂqމЭٙઋbIرɨd˒ฌ൯ආλٙ૿ଌόѩፅf ˴ɢฌٙѩፅً࿒ʱؓjбৃࢹ݊щՈϞ৷జᎵk
ࠬᎈ၍ଣኪజ 157ୋɖ՜ ୋɚಂ2005ϋ7˜ a. ίٰୃॆྼᄆЗɪʺRٙઋرɨ H߰бৃࢹˢбॆৃࢹٙజᎵމ৷d̀ୌΥj IIUIIUV(R,λ,λ)V(R,λ,λ)>(55) HSsHBbՉʕ IIUIUV(R,λ,λ)=α(R−P)+λ(R−P) (14)HSs1HSsHSsIIUIUV(R,λ,λ)=α(R−P)−λ(R−P) (6) HBb1HBbHBbIUU(14)ό-(6)ό=α(P−P)+λ(R−P)+λ(R−P)>0 (56) 1BSsHSsbHBbΪމ(56)όܩމ͍࠽dΪϤdίٰୃॆྼᄆЗɪʺٙઋرɨd˴ɢIλбৃࢹd͵уር̈ഄଫλdႰԴ˒༧ආd˸ᐏ՟༰৷ٙజᎵdSϤމᏀЭіഄଫf ίٰୃॆྼᄆЗɨࠥRٙઋرɨ L߰бৃࢹˢбॆৃࢹٙజᎵމ৷d̀ୌΥj IIUIIUV(R,λ,λ)>V(R,λ,λ)(57) LBbLSsՉʕ IIUIUV(R,λ,λ)=−α(P−R)+λ(P−R) (17) ;Bb1BLbBbLIIUIUV(R,λ,λ)=−α(P−R)−λ(P−R)(16)LSs1SLsSsLIUU(17)ό-(16)ό=α(P−P)+λ(P−R)+λ(P−R) (58) 1SBsSsLbBbL(58)όί˸ɨૢϓͭɨމɓ͍࠽j UUλ(P−R)+λ(P−R)IsSsLbBbLα<(59)1P−PBSP≈R;P≈Rࣛdɪό̙˸ᄳϓj SsLBbHUλ(R−R)IbHLα< (59a) 1P−PBSΪމP−R>P−PdΪϤd(59a)މɓᖢ֛ૢf HLBSb. ίٰୃॆྼᄆЗɨࠥٙઋرɨdί(59a)ૢϓͭɨd˴ɢλбৃ
158ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ Iࢹd͵у൯ɝഄଫλdႰԴ˒༧ආd˸ᐏ՟༰৷ٙజᎵdމז৷B̈ഄଫf c. ˴ɢၾ˒ٙజᎵʱؓ (i) ࿁˴ɢϾԊ Ϊމ̹ఙ̥πίᖢ֛ٙ૿ଌόѩፅd˴ɢΪމՈϞᜳஷৃࢹdλбৃࢹd͵уίᅺٰٙୃॆྼᄆЗމ৷Эࣛdбር̈൯ආٙৃdႰԴ˒༧ආdۃ٫జᎵܩމ৷జᎵdܝ٫ίᖢ֛ૢɨ͵̙ᐏˢбॆৃࢹ༰৷ٙజᎵf (ii) ࿁˒ϾԊ 1. Ϊމ̹ఙ̥πίᖢ֛ٙ૿ଌόѩፅd˒ʔՈϞᜳஷٙৃࢹd̀ኯᔟ࿁ᅺٰٙୃ͊ԸॆྼᄆЗʘڦׂආБкᓙf˒࿁͊ԸॆྼᄆЗIމЭٙڦׂʔ৷ࣛdฌ൯ආλ૿ଌόѩፅdϤɓڦׂա˴ɢୋɓಂBIIٰܵˢԷαٙᅂᚤfԱ(51)όd˸ɨૢϓͭࣛd˒ίλ૿ଌό1BѩፅʕٙಂૐజᎵމ͍f IUα(R−P)−λ(R−P)*+1HBbHBbq>=q (60) bIU(α−λ)(R−R)1bHLP≈Rd(60)ό̙˸ࠠอଣމj BbHIUα(R−R)−α(P−R)*+1HL1BLq=<1(60a) bIUα(R−R)−α(R−R)1HLbHLIUα(P−R)>α(R−R)͵у dא(61)1BLbHLIα(P−R)UU*1BLα<=α(61a) bbR−RHL͵у˒߰ڢٛͦɽඎ༧ආ൯ආഄଫdಂૐజཇʥ̙މ͍f 2. ͟˴ɢλί૿ଌόѩፅʕбৃࢹd͵уί͊Ըॆྼజཇމ৷ЭઋҖɨdбር̈൯ආٙৃdႰԴ˒༧ආd˸ɨʱйীሞίО၇ઋرɨd˒ʥ̙ᆽڭՉజᎵމ͍f (1) ί͊ԸॆྼᄆЗމ৷ٙઋرɨdԱ(21)όdٝ˒ٙజᎵՌᅰމj UIUIUV(R,λ,λ)=−[α(R−P)+λ(R−P)]<0 (21)HSs1HSsHSs͵у˒జᎵܩމࠋf
ࠬᎈ၍ଣኪజ 159ୋɖ՜ ୋɚಂ2005ϋ7˜ (2) ί͊ԸॆྼᄆЗމЭٙઋرɨdԱ(24)όdٝ˒ٙజᎵՌᅰމj UIUIUV(R,λ,λ)=α(P−R)−λ(P−R) (24) LBb1BLbBbL˸ɨૢϓͭɨd(24)ό̙˸މ͍j Iα(P−R)UU*'1BLλ<=λ (62) bbP−RBbLP≈Rࣛd(62)ό≈(61a)ό BsLնᕚ4jί༟ৃʔ࿁၈ᒄ҅ʕd˴ɢλί૿ଌόѩፅʕбৃࢹ˸ႰԴ˒༧ආdɽʷՉజᎵfίᅺٰٙୃ͊ԸॆྼᄆЗމ৷ٙઋرɨd˴ɢбৃࢹഄଫν؈ϓ̌dజᎵܩމ͍࠽d˒జᎵܩމࠋ࠽fШίᅺٰٙୃ͊ԸॆྼᄆЗމЭٙઋرɨd˴ɢбৃࢹഄଫ݊щϓ̌d̀˒ٛͦɽඎ༧ආ൯ɝৣΥʑঐᆽڭՉ༰Ꮅމ͍dщۆ͵ϞజᎵމࠋ̙ٙঐf d. ѩፅٙจ ί༟ৃʔ࿁၈ᒄ҅ʕd˴ɢλί૿ଌόѩፅʕбৃࢹ˸ႰԴ˒༧ආfίᅺٰٙୃ͉ԸॆྼᄆЗމ৷ٙઋرɨd˴ɢбৃࢹഄଫν؈ϓ̌dజᎵܩމ͍࠽fШίᅺٰٙୃ͊ԸॆྼᄆЗЭٙઋرɨd˴ɢбৃࢹഄଫ݊щϓ̌d̀˒ٛͦɽඎ༧ආ൯ɝৣΥʑঐᆽڭՉ༰Ꮅމ͍dщۆ͵ϞజᎵމࠋ̙ٙঐfϤɓഐ؈ʔШ̙ၾԫྼɪٰୃ̹ఙʕ˴ɢזױٰᄆ࢙ë୭ᗭɪᗗ࢙ɨᗗᗭΙᗇjεٙɽ˒ɝІ6ʉהணٙԥʕೌجІנуމᗇf͵̙ᗇ˒ٙ༧Бމ݊πί˲݊ଣٙfNofsinger & Sias, 1999iDevenow & Welch, 1996 6. ഐሞၾܔᙄ ͟ɪࠑٙᒄ҅પစd͉Ӻᐏߧ˴ࠅഐሞνɨj (1) ᗇՎ̹ఙπί༟ৃʔ࿁၈ٙઋرɨdೌᜳஷऊࢹٙ˒ίݔԬૢɨึԱኽᜳஷऊࢹٙ˴ɢdνІᐄਠeجɛҳ༟ዚeਿږʮ̡eҳ༟ᚥਪʮ̡אՉ̴ʫᗫڷɛٙҳ༟Бމהбٰٙܵৃࢹમ՟Чٙҳ༟Бމd͵у༧ҳ༟БމίᗇՎ̹ఙʕ݊πίdϾ˲݊ଣٙf 6 ੵဤdٰୃૄԐ̈ɓ၊dଣҳ༟ৎႀdʈਠࣛజৌኪd1995ϋ3˜6˚f
160ᗇՎ̹ఙ˴ɢၾ˒ҳ༟ɛ༧БމʘӺÑɓࡈᔊఊٙᒄ҅ᅼۨ I(2) ίλৃࢹ૿ଌɨd߰˴ɢႩމ͊ԸॆྼᄆЗਗ਼ɨࠥdϾ˒Ⴉމ͊BԸॆྼᄆЗਗ਼ɨࠥٙڦׂ࠽qʃqމʃ1͍ٙᅰԨ˲db߰j Iα(P−P)UI1BS λ>>0ࣛdۆπίഹλৃࢹ૿ଌόҁߕԎˤѩፅً࿒f bBP−PBbSbI(3) ίλৃࢹ૿ଌɨd߰˒Ⴉމ͊ԸॆྼᄆЗਗ਼ɨࠥٙڦׂ࠽qɽBIqމʃ1͍ٙᅰfۆπίഹλৃࢹ૿ଌόҁߕԎˤѩፅً࿒f sS*qb(4) ί˒࿁͊ԸٰୃॆྼᄆЗɨൻ̙ٙঐٙڦׂމЭٙઋرIλBɨd˒ฌ൯ආٙ૿ଌόѩፅf (5) ί༟ৃʔ࿁၈ᒄ҅ʕd˴ɢλί૿ଌόѩፅʕбৃࢹ˸ႰԴ˒༧ආdɽʷՉజཇfίᅺٰٙୃ͉ԸॆྼᄆЗމ৷ٙઋرɨd˴ɢбৃࢹഄଫ (ᏀЭіഄଫ)dν؈ϓ̌dజᎵܩމ͍࠽d˒జᎵܩމࠋ࠽fШίᅺٰٙୃ͊ԸॆྼᄆЗЭٙઋرɨd˴ɢбৃࢹഄଫ (ז৷̈ഄଫ) ݊щϓď̀˒ٛͦɽඎ༧ආ൯ɝৣΥʑঐᆽڭՉజᎵމ͍dщۆ͵Ϟజཇމࠋ̙ٙঐf ͉˖˸ৃࢹбᒄ҅d࿁ᗇՎ̹ఙ˒ҳ༟ɛί༟ৃʔ࿁၈ɨʘҁΌԎˤѩፅٙ༧Бމ̈ə༆ᙑdމʫٰୃ̹ఙආБྼᗇԶəଣሞʘਿᓾf್Ͼd̹ఙʕΝɓᅺٰ̙ٙঐΝࣛϞεࡈ˴ɢʧɝЪdՉගٙЪجᏐၾ͉˖ʘఊɓ˴ɢٙઋرϞהʔΝdޟЇପ͛ላ߉d࠽͊ԸආɓӉଉɝઞীf ̤̮d͉˖ίண̹ఙʫπίɓЗऊࢹᜳஷٙ˴ɢҳ༟٫ࣛdઞী˒ί༟ৃʔ࿁၈ɨʘҁߕԎˤѩፅٙ༧БމdՉʕɚࡈ૿Υ༆ྼމʱѩፅ ( partial equilibrium )dމӋһՈɓছʷٙʹѩፅᅼۨdྼމшɛ͊ԸӺʘ˙Σf ਞϽ˖ᘠ 1. ˮΌສdɪ̹ʮ̡ʫᗫڷɛʘ͡జᔷᜫٰܵၾ̹ఙࣖଟʘྼᗇӺdၽᝄɽኪਠה၂ɻሞ˖d1991ϋf 2. Ϫ҃ኊdٰୃ̹ఙБމʘઞীjอጳ̹ఙၾʊක೯ʘˢ༰dͭ৷ඪୋɓ߅Ҧɽኪৌਕ၍ଣה၂ɻሞ˖d2002ϋf 3. ؍ͺٓdዚҳ༟ɛБމӺ─˸ʫ܆ௐόਿږމԷdͭʕʆɽኪΆุ၍ଣӺה၂ɻሞ˖d1996ϋf 4. ؍ཡೡdʫΝਿږତʿࡡΪʱؓdͭථ؍߅ҦɽኪΆุ
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