0 Yi-Shin Chen and Cyrus Shahabi nism. The chromosomes represent a possible user profile. Two ty pes of records are involved in the genes. One is user confidence information with k records where k is the number of experts in the system. The value of the ith gene is an integer in 0, P-1, where P is the number of fuzzy terms used in the ystem, and denotes the user's confidence level to expert i. The e othe r fuzzy cut value which is associated with the gl: 1 )th gene. The value of fuzzy cut is g +1)/P, where t E 0, P-1 is the value of this gene or example, suppose that there are 50 experts and 8 different fuzzy terms in the system, there will be 51 genes per chromosome where the first 50 genes represent the corresponding confidence values to the experts, and the last gene represents the value of the user fuzzy cut. Additionally, after decoding the value of 0 in gene i indicates that the confidence level to user i is "none and the value of 6 in gene 51 indicates that the value of fuzzy cut is g+1)/8=0.875. Likewise, after encoding, "full "confidence level to user i is represented by a number 7 in gene i and the 0.75 fuzzy cut is denoted by number 5 in gene 51 This coding method can guarantee a one-to-one mapping of profiles to hromosomes. That is, a chromosome will be decoded to one and only one legal user profile, and a user profile will be encoded to one chromosome. Consequently, the solution space will be equal to the searching space in GA. This implies that our coding method is effective Next, we describe our GA fitness function, which heavily utilizes the pref- erence list B estimated by our converting method. The fitness function first decodes the chromosome into a confidence list and a fuzzy cut value. Then, it obtains the user wish-list Q according to the profile using Equation g) In other words, this process needs to interact with the system for obtaining exp sh- lists. Finally, it generates the fitness value by measuring the similarity between Q and B. The similarity values are computed by Equa tion g 2) which is based on two measurements. Equation gO) evaluates the similarity on ranking, and Equation g 1)measures the average satisfaction of the user wish-list {g,ng)ng))∈0,1 g,tng)tg)∈[0,1]} ∑;vng)×g) g0) 2∑;ungn×∑tg)n t∈Q du g) g1) Q I the le tri the learn nism first converts the navigation behaviors to relevance feedback. Next, it￾❫❶ ➳✸❵ ❸❡❜✦✇♥❵❚①❤✕✇♥❳✽❚✵❬✍❚❉❪①❤✈❝✦❩❇♠♥❞❍❜✦✇❉❬✍✇❉❬✍➝♥❵ ❆❉❖❊❘▲◗❭■❦Ñ♥❖❊■✍❋♥❒PÏ▼❛❐✍ç✐■✼■✣é⑧ß❊Ï④❏✦❃❋➽❒P❈❊■✐➮✣➱⑧❑⑧❃❋❊Ð✡❑⑧■❦◗❭❃Ð❛❋➽❮➊➱❛◆■✮Þ◗✈❃❋✛➱❛❖❊◆✂Ï■❦❏✦◆P❋❊❃❋❊Ð✖✃✵■❦➮✽❈▲❏❲❅ ❋❊❃④◗❭✃✝ätæ✸❈❊■✐➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■❦◗➤◆P■✍ß❊◆P■❦◗❭■✍❋♥❒✈❏✱ß➩➱♥◗P◗❭❃❘❊Ï■❍❖▲◗❭■✍◆✈ß❊◆P➱✥￾▲Ï■❛ä❦æ✸ç✐➱✸❒❇▼❉ß➩■❦◗✈➱✦❮❊◆P■❦➮✣➱❛◆✽❑❊◗ ❏✦◆P■✡❃❋❉Ò❛➱❛ÏÒ❛■❦❑①❃❋➧❒P❈❊■❄Ð❛■✍❋❊■❦◗✍ä ✺❋❊■❄❃④◗✐❖▲◗❭■✍◆✱➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■❄❃❋⑧❮➊➱❛◆P✃①❏❲❒P❃➱❛❋➧ç✱❃❒P❈✙✰➢◆P■❦➮✣➱❛◆✽❑❊◗✍❐ ç✱❈❊■✍◆P■ ✰✢❃④◗➽❒P❈❊■①❋❉❖❊✃✧❘➩■✍◆✛➱✦❮✐■✣é⑧ß➩■✍◆❭❒✽◗❣❃❋á❒P❈❊■➢◗❭▼⑧◗❇❒P■✍✃✝ä✈æ✸❈❊■①Ò❲❏✦Ï❖❊■✵➱✦❮✐❒P❈❊■✑✔❯❒P❈ Ð❛■✍❋❊■ ❃④◗✡❏✦❋✝❃❋♥❒P■✍Ð❛■✍◆✖❃❋ ✯❭★✔✁￾✄✂❫✱✟✸❡❐❊ç✱❈❊■✍◆P■☎￾⑩❃④◗✱❒P❈❊■✛❋❉❖❊✃✧❘➩■✍◆✡➱✦❮②❮➊❖❊❰✍❰✍▼➧❒P■✍◆P✃①◗✱❖▲◗❭■❦❑✝❃❋✿❒P❈❊■ ◗❭▼⑧◗❇❒P■✍✃✝❐✕❏✦❋▲❑à❑⑧■✍❋❊➱✦❒P■❦◗❣❒P❈❊■➧❖▲◗❭■✍◆❦ü ◗✛➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■➢Ï■✍Ò❛■✍Ï✼❒P➱å■✣é⑧ß➩■✍◆❭❒✚✔✽ä✕æ✸❈❊■➢➱✦❒P❈❊■✍◆✧❃④◗✧❏ ❖▲◗❭■✍◆✡❮➊❖❊❰✍❰✍▼✿➮✣❖⑧❒➽Ò❲❏✦Ï❖❊■✧ç✱❈❊❃④➮✽❈å❃④◗❄❏❛◗P◗❭➱⑧➮✣❃④❏❲❒P■❦❑✝ç✱❃❒P❈å❒P❈❊■ ✜ ✰ ✧ ✱✤✣❡❒P❈✢Ð❛■✍❋❊■❛ä➤æ✸❈❊■✧Ò❲❏✦Ï❖❊■ ➱✦❮✕❮➊❖❊❰✍❰✍▼➧➮✣❖⑧❒✖❃④◗ ✜✝✆ ✧ ✱✤✣✁✞✟￾✖❐❉ç✱❈❊■✍◆P■✠✆ ✜ ✯❭★✔✁￾✡✂❨✱✟✸✂❃④◗✸❒P❈❊■❣Ò❲❏✦Ï❖❊■➽➱✦❮✕❒P❈❊❃④◗✱Ð❛■✍❋❊■❛ä ❃❊➱❛◆☞■✣é❊❏✦✃✵ß❊Ï■❛❐✱◗❭❖❊ß❊ß➩➱♥◗❭■✢❒P❈▲❏❲❒☞❒P❈❊■✍◆P■ ❏✦◆P■ ✁ ❭➯■✣é⑧ß➩■✍◆❭❒✽◗✝❏✦❋▲❑❙❱➯❑⑧❃â➤■✍◆P■✍❋♥❒✝❮➊❖❊❰✍❰✍▼ ❒P■✍◆P✃①◗✡❃❋✿❒P❈❊■✵◗❭▼⑧◗❇❒P■✍✃✝❐▲❒P❈❊■✍◆P■✧ç✱❃ Ï Ï✕❘➩■ ✁ ✱✛Ð❛■✍❋❊■❦◗✡ß➩■✍◆➽➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■❣ç✱❈❊■✍◆P■✛❒P❈❊■ ￾▲◆✽◗❇❒ ✁ ❭☞Ð❛■✍❋❊■❦◗❣◆P■✍ß❊◆P■❦◗❭■✍❋♥❒➽❒P❈❊■➢➮✣➱❛◆P◆P■❦◗❭ß➩➱❛❋▲❑⑧❃❋❊Ð✝➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■①Ò❲❏✦Ï❖❊■❦◗➽❒P➱✝❒P❈❊■①■✣é⑧ß➩■✍◆❭❒✽◗✍❐✈❏✦❋▲❑ ❒P❈❊■①Ï④❏❛◗❇❒✛Ð❛■✍❋❊■①◆P■✍ß❊◆P■❦◗❭■✍❋♥❒✽◗✡❒P❈❊■➢Ò❲❏✦Ï❖❊■①➱✦❮✐❒P❈❊■①❖▲◗❭■✍◆➽❮➊❖❊❰✍❰✍▼ ➮✣❖⑧❒❦ä Þ❑❊❑⑧❃❒P❃➱❛❋▲❏✦Ï Ï▼❛❐✈❏❲❮➀❒P■✍◆ ❑⑧■❦➮✣➱⑧❑⑧❃❋❊Ð▲❐❛❒P❈❊■✡Ò❲❏✦Ï❖❊■✡➱✦❮ ❭❣❃❋➧Ð❛■✍❋❊■ ✔②❃❋▲❑⑧❃④➮✍❏❲❒P■❦◗✼❒P❈▲❏❲❒✐❒P❈❊■❄➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■✡Ï■✍Ò❛■✍Ï▲❒P➱✧❖▲◗❭■✍◆ ✔ ❃④◗①ê❭❋❊➱❛❋❊■❦ø✵❏✦❋▲❑➧❒P❈❊■✛Ò❲❏✦Ï❖❊■❣➱✦❮❁✵✵❃❋✝Ð❛■✍❋❊■ ✁ ✱➽❃❋▲❑⑧❃④➮✍❏❲❒P■❦◗✸❒P❈▲❏❲❒✱❒P❈❊■✛Ò❲❏✦Ï❖❊■❣➱✦❮✕❮➊❖❊❰✍❰✍▼✝➮✣❖⑧❒ ❃④◗ ✜✪✵ ✧ ✱✤✣✁✞✞❱ ✏✫❭☞☛ ❱✙❪ ✁ ä✰✱✂❃Ó❛■✍ç✱❃④◗❭■❛❐❊❏❲❮➀❒P■✍◆✱■✍❋▲➮✣➱⑧❑⑧❃❋❊Ð▲❐✼ê❇❮➊❖❊Ï Ï④ø①➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■➽Ï■✍Ò❛■✍Ï❁❒P➱①❖▲◗❭■✍◆ ✔②❃④◗❍◆P■✍ß❊◆P■❦◗❭■✍❋♥❒P■❦❑✵❘❉▼①❏✛❋❉❖❊✃✧❘➩■✍◆✛❪➽❃❋➢Ð❛■✍❋❊■ ✔✟❏✦❋▲❑✵❒P❈❊■✭❭☞☛ ❪ ✁ ❮➊❖❊❰✍❰✍▼①➮✣❖⑧❒✸❃④◗✐❑⑧■✍❋❊➱✦❒P■❦❑①❘❉▼ ❏✮❋❉❖❊✃✧❘➩■✍◆ ✁ ❃❋✝Ð❛■✍❋❊■ ✁ ✱❛ä æ✸❈❊❃④◗✮➮✣➱⑧❑⑧❃❋❊Ð✢✃✵■✣❒P❈❊➱⑧❑➯➮✍❏✦❋ Ð❛❖▲❏✦◆✽❏✦❋♥❒P■✍■➢❏å➱❛❋❊■✣❅❯❒P➱✦❅❡➱❛❋❊■➢✃①❏✦ß❊ß❊❃❋❊Ð✢➱✦❮✡ß❊◆P➱✥￾▲Ï■❦◗❣❒P➱ ➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■❦◗✍ä❁æ✸❈▲❏❲❒✛❃④◗✍❐✈❏✝➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■✮ç✱❃ Ï Ï❍❘➩■➢❑⑧■❦➮✣➱⑧❑⑧■❦❑✢❒P➱✿➱❛❋❊■➢❏✦❋▲❑á➱❛❋❊Ï▼å➱❛❋❊■ Ï■✍Ð♥❏✦Ï✱❖▲◗❭■✍◆①ß❊◆P➱✥￾▲Ï■❛❐❍❏✦❋▲❑ö❏ ❖▲◗❭■✍◆①ß❊◆P➱✥￾▲Ï■✝ç✱❃ Ï Ï✡❘➩■✿■✍❋▲➮✣➱⑧❑⑧■❦❑➯❒P➱à➱❛❋❊■✿❏✦❋▲❑ö➱❛❋❊Ï▼ ➱❛❋❊■ ➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■❛ä⑧●❍➱❛❋▲◗❭■❦Ñ♥❖❊■✍❋♥❒PÏ▼❛❐♥❒P❈❊■❣◗❭➱❛Ï❖⑧❒P❃➱❛❋☞◗❭ß▲❏❛➮✣■❄ç✱❃ Ï Ï❁❘➩■❄■❦Ñ♥❖▲❏✦Ï➩❒P➱✮❒P❈❊■❣◗❭■❦❏✦◆✽➮✽❈❊❃❋❊Ð ◗❭ß▲❏❛➮✣■➽❃❋✕✮Þ ä▲æ✸❈❊❃④◗✸❃✃✵ß❊Ï ❃■❦◗✸❒P❈▲❏❲❒✖➱❛❖❊◆✖➮✣➱⑧❑⑧❃❋❊Ð✵✃✵■✣❒P❈❊➱⑧❑☞❃④◗✱■✣â➤■❦➮❫❒P❃Ò❛■❛ä ✝✖■✣é❉❒❦❐✦ç✐■✖❑⑧■❦◗P➮✣◆P❃❘➩■✸➱❛❖❊◆✎✮Þ ￾❊❒P❋❊■❦◗P◗②❮➊❖❊❋▲➮❫❒P❃➱❛❋✂❐❛ç✱❈❊❃④➮✽❈✵❈❊■❦❏tÒ❉❃ Ï▼✛❖⑧❒P❃ Ï ❃❰✍■❦◗②❒P❈❊■✱ß❊◆P■✣❮➀❅ ■✍◆P■✍❋▲➮✣■❣Ï ❃④◗❇❒ ✭ ■❦◗❇❒P❃✃①❏❲❒P■❦❑☞❘❉▼☞➱❛❖❊◆✡➮✣➱❛❋❉Ò❛■✍◆❭❒P❃❋❊Ð✮✃✵■✣❒P❈❊➱⑧❑❁ä➤æ✸❈❊■✭￾❊❒P❋❊■❦◗P◗✱❮➊❖❊❋▲➮❫❒P❃➱❛❋ ￾▲◆✽◗❇❒ ❑⑧■❦➮✣➱⑧❑⑧■❦◗✱❒P❈❊■✮➮✽❈❊◆P➱❛✃✵➱♥◗❭➱❛✃✵■➽❃❋♥❒P➱➧❏➧➮✣➱❛❋❆￾➩❑⑧■✍❋▲➮✣■✛Ï ❃④◗❇❒❄❏✦❋▲❑å❏✵❮➊❖❊❰✍❰✍▼✝➮✣❖⑧❒❄Ò❲❏✦Ï❖❊■❛ä➤æ✸❈❊■✍❋✂❐ ❃❒✧➱❛❘⑧❒✽❏✦❃❋▲◗➽❒P❈❊■➢❖▲◗❭■✍◆✛ç✱❃④◗❭❈⑧❅❡Ï ❃④◗❇❒✍✌ ❏❛➮✍➮✣➱❛◆✽❑⑧❃❋❊Ð☞❒P➱✝❒P❈❊■➢ß❊◆P➱✥￾▲Ï■①❖▲◗❭❃❋❊Ð ✟❍Ñ♥❖▲❏❲❒P❃➱❛❋ ✜✪✵ ✣❫ä èq❋✿➱✦❒P❈❊■✍◆✡ç✐➱❛◆✽❑❊◗✍❐⑧❒P❈❊❃④◗✡ß❊◆P➱⑧➮✣■❦◗P◗✱❋❊■✍■❦❑❊◗✱❒P➱➢❃❋♥❒P■✍◆✽❏❛➮❫❒✖ç✱❃❒P❈✿❒P❈❊■✮◗❭▼⑧◗❇❒P■✍✃ ❮➊➱❛◆✡➱❛❘⑧❒✽❏✦❃❋❊❃❋❊Ð ■✣é⑧ß➩■✍◆❭❒✽◗✍ü✕ç✱❃④◗❭❈⑧❅❡Ï ❃④◗❇❒✽◗✍ä■❃✕❃❋▲❏✦Ï Ï▼❛❐②❃❒✵Ð❛■✍❋❊■✍◆✽❏❲❒P■❦◗❣❒P❈❊■ ￾❊❒P❋❊■❦◗P◗✮Ò❲❏✦Ï❖❊■➧❘❉▼ ✃✵■❦❏❛◗❭❖❊◆P❃❋❊Ðå❒P❈❊■ ◗❭❃✃✵❃ Ï④❏✦◆P❃❒❇▼å❘➩■✣❒❇ç✐■✍■✍❋✎✌✥❏✦❋▲❑ ✭➢ä✕æ✸❈❊■➢◗❭❃✃✵❃ Ï④❏✦◆P❃❒❇▼åÒ❲❏✦Ï❖❊■❦◗✛❏✦◆P■①➮✣➱❛✃✵ß❊❖⑧❒P■❦❑á❘❉▼ ✟❍Ñ♥❖▲❏❲❅ ❒P❃➱❛❋ ✜ ✱✤✷❉✣✱ç✱❈❊❃④➮✽❈✿❃④◗✡❘▲❏❛◗❭■❦❑✝➱❛❋✿❒❇ç✐➱➢✃✵■❦❏❛◗❭❖❊◆P■✍✃✵■✍❋♥❒✽◗✍ä✗✟❍Ñ♥❖▲❏❲❒P❃➱❛❋✁✜ ✱✶❭ ✣✸■✍Ò❲❏✦Ï❖▲❏❲❒P■❦◗✖❒P❈❊■ ◗❭❃✃✵❃ Ï④❏✦◆P❃❒❇▼å➱❛❋à◆✽❏✦❋❊Ó❉❃❋❊Ð▲❐✂❏✦❋▲❑ ✟❍Ñ♥❖▲❏❲❒P❃➱❛❋❫✜ ✱❉✱✤✣❄✃✵■❦❏❛◗❭❖❊◆P■❦◗❄❒P❈❊■➧❏tÒ❛■✍◆✽❏✦Ð❛■✵◗P❏❲❒P❃④◗❇❮❾❏❛➮❫❒P❃➱❛❋ ➱✦❮✕❒P❈❊■❣❖▲◗❭■✍◆✱ç✱❃④◗❭❈⑧❅❡Ï ❃④◗❇❒❦ä ✌ ✏ ✒✙✜ ✔✌✔✦✥✛✆✜ ✔ ✣ ✣ ✖ ✥✛✴✜ ✔ ✣ ✣ ✜ ✯❭★✔✄✱✟✸ ✘ ✭ ✏ ✒✙✜ ✔✌✔ ✥✌ ✛✆✜ ✔ ✣ ✣ ✖ ✥✌✛✴✜ ✔ ✣ ✜ ✯❭★✔✄✱✟✸ ✘ ●❍➱♥◗✑✏❛✜✒✌ ✔ ✭✻✣ ✏ ✓✖ ✥✛✴✜ ✔ ✣✞❅ ✥✌✛✆✜ ✔ ✣ ✔ ✓✖ ✥✛✴✜ ✔ ✣ ✝ ❅ ✓ ✥✌✛✴✜ ✔ ✣ ✝ ✜ ✱✶❭ ✣ ✚✥￾❀✜✒✌ ✔ ✭✻✣ ✏ ✓✖ ✵✖✕ ✥✌✛✴✜ ✔ ✣ ✬✗✌ ✬ ✜ ✱❉✱✤✣ ❆❉❃✃✵❃ Ï④❏✦◆P❃❒❇▼✴✜✒✌ ✔ ✭✻✣ ✏ ●❍➱♥◗✑✏❛✜✒✌ ✔ ✭✻✣ ✧ ❚ ❅✛✚✥￾❀✜✪✭ ✔✘✌ ✣ ✜ ✱✤✷❉✣ èq❋ ◗❭❖❊✃✵✃①❏✦◆P▼❛❐➤➱❛❋▲➮✣■✧❒P❈❊■✵Ï■❦❏✦◆P❋❊❃❋❊Ð☞ß❊◆P➱⑧➮✣■❦◗P◗✡❃④◗❄❒P◆P❃Ð❛Ð❛■✍◆P■❦❑❁❐▲❒P❈❊■✵Ï■❦❏✦◆P❋❊❃❋❊Ð☞✃✵■❦➮✽❈▲❏❲❅ ❋❊❃④◗❭✃ ￾▲◆✽◗❇❒✛➮✣➱❛❋❉Ò❛■✍◆❭❒✽◗✖❒P❈❊■①❋▲❏tÒ❉❃Ð♥❏❲❒P❃➱❛❋å❘➩■✍❈▲❏tÒ❉❃➱❛◆✽◗✡❒P➱☞◆P■✍Ï■✍Ò❲❏✦❋▲➮✣■✮❮➊■✍■❦❑⑧❘▲❏❛➮✽Ó➤ä ✝✖■✣é❉❒❦❐❁❃❒