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A tool for Multi-Strategy Learning

Abstract

This paper presents the AFRANCI tool for the development of Multi-Strategy learning systems. AFRANCI allows users to build, in an interactive and easy way, complex systems. Systems are built using a two step methodology: design of the structure of the system; and fill in the modules. The structure of the target system is a collection of interconnected modules. The user may then choose among a variety of learning algorithms to construct each module. The tool has several built-in Machine Learning algorithms and interfaces that enable it to use external learning tools like WEKA or CN2. AFRANCI uses the interdependency of the modules to determine the sequence of their training. To improve usability, the tool uses a wrapper that hides from the user the parameter tuning procedure for each algorithm. In a final step of the design sequence AFRANCI generates a compact and legible ready-to-use ANSI C++ open-source code for the final system. To illustrate the concept we have empirically evaluated the tool in the context of the RoboCup Rescue domain. We have developed a small system that uses both neural networks and rules in the same system. The experiment have shown that a very significant speed up is attained in the development of systems when using this tool.

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A tool for Multi-Strategy Learning

Author: Francisco Reinaldo,Marcus Siqueira,Rui Camacho,Luís Paulo Reis
Year: 2006
Source: https://repositorio-aberto.up.pt/bitstream/10216/67130/2/69530.pdf
A ool o Mul i-S a egy Lea ning
F ancisco Reinaldo1,2, Ma cus Siquei a1,2, Rui Camacho1, and Lu´ıs Paulo Reis1
1LIACC, Facul y o Enginee ing, Uni e si y o Po o, Po ugal
2GIC, Depa men o Compu e Science, Uniles eMG, B azil
ei eup, camacho,lp eis{@ e.up.p },[email p o ec ed]
Abs ac . This pape p esen s he AFRANCI ool o he de elopmen
o Mul i-S a egy lea ning sys ems. AFRANCI allows use s o build, in
an in e ac i e and easy way, complex sys ems. Sys ems a e buil using a
wo s ep me hodology: design o he s uc u e o he sys em; and ill in
he modules. The s uc u e o he a ge sys em is a collec ion o in e con-
nec ed modules. The use may hen choose among a a ie y o lea ning
algo i hms o cons uc each module. The ool has se e al buil -in Ma-
chine Lea ning algo i hms and in e aces ha enable i o use ex e nal
lea ning ools like WEKA o CN2. AFRANCI uses he in e dependency
o he modules o de e mine he sequence o hei aining. To imp o e
usabili y, he ool uses a w appe ha hides om he use he pa am-
e e uning p ocedu e o each algo i hm. In a inal s ep o he design
sequence AFRANCI gene a es a compac and legible eady- o-use ANSI
C++ open-sou ce code o he inal sys em.
To illus a e he concep we ha e empi ically e alua ed he ool in he
con ex o he RoboCup Rescue domain. We ha e de eloped a small
sys em ha uses bo h neu al ne wo ks and ules in he same sys em.
The expe imen ha e shown ha a e y signi ican speed up is a ained
in he de elopmen o sys ems when using his ool.
1 In oduc ion
O e he pas ew yea s, he e has been a signi ican inc ease in he in e es
o wo king wi h he e ogeneous lea ning algo i hms in o de o achie e as and
complex beha iou s in au onomous agen s. An Au onomous Agen (AA) can
be seen as a collec ion o componen s o he e ogeneous lea ning modules wi h
well-de ined in e aces and ine uned beha iou s. I has been ecognised ha
di e en beha iou s may equi e di e en lea ning s a egies.
A popula AA a chi ec u e conside s se e al lea ning algo i hms/modules
a anged in ho izon al and/o e ical le els o compose beha iou s wi h di e en
le els o abs ac ion. This laye ed lea ning is specially adequa e o domains ha
a e oo complex o a di ec mapping om he inpu o he ou pu ep esen a ion
o wo k [1]. This app oach b ings some new challenges on he a angemen o
hese modules o achie e inne easoning, p edic ion and abs ac ion me hods
ins ead o classical planning esea ch. Addi ionally, he use o obus ools a e
necessa y o suppo his kind o app oach. Al hough no in he con ex o AA
© A. Gelbukh, C.A. Reyes-Ga cía. (Eds.)
Ad ances in A i icial In elligence.
Resea ch in Compu ing Science 26, 2006, pp. 51-59
Recei ed 02/06/06
Accep ed 03/10/06
Final e sion 11/10/06
cons uc ion, bu also using a hie a chical o ganisa ion o modules, Alan Shapi o
[2] p oposes he use o “s uc u ed induc ion” o add ess he p oblem o inducing
complex concep s.
Howe e , when using a con en ional p og amming language, like C o C++
o encode such modules, an expe p og amme is o en equi ed. Each new
use s a s a p ojec om sc a ch, and occasionally i esul s in a bad p og am
code s uc u e e ealing p oblems whene e he code needs o be ex ended o
upda ed. To o e come such di icul ies some ools p opose uni o m and easily
modelling acili ies o he lea ning modules. Such ools include Ma lab c
[3]
and SNNS (S u ga Neu al Ne wo k Simula o ) c
[4] and [5]. These ools a e
limi ed as a as he use in e ace aspec s a e conce ned since hese a e o en
neglec ed. In addi ion, he ools do no suppo he design o se e al modula ,
hie a chic and complex s uc u es o he e ogeneous lea ning modules in he same
en i onmen as AFRANCI does.
The AFRANCI ool [6] o e s solu ions o assembling and linking oge he
g aphically on he sc een he modules equi ed o c ea e la ge scale beha iou -
based sys ems. In he de elopmen o AA applica ions he e is he need o agg e-
ga e di e en kinds o beha iou s wo king oge he o inc ease he complexi y
o beha iou s. The use ’s choice is no es ic ed o low le els bu is ee o
choose he sui able abs ac ion le el. Ano he ad an age o AFRANCI is he
possibili y o using ex e nal lea ning ools/algo i hms such as he WEKA [7]
lib a y o CN2 induc ion algo i hm [8] o compose he e ogeneous lea ning mod-
ules. The ool makes easily adjus able and ex ensible connec ion wi h WEKA
lea ning modules and CN2 wi hou he use ’s pe cep ion. These aspec s will be
p esen ed in Sec ion 2.
Acco ding o he p oposed objec i es, his wo k has enabled he de elopmen
o a ool ha can: a) suppo g aphic designs o la ge and ex ensible beha iou -
based a chi ec u es composed o he e ogeneous clus e s wi h cogni i e p ocesses;
b) make a ailable a wide se o a ied unc ionali ies o con ol modules; c)
o e acili ies and esou ces o in e connec se e al s uc u es o ex e nal con ol
p ocesses so ha hey could communica e in a mul i-en i onmen ; d) a ange
lea ning modules in ho izon al o e ical le els o inse new o subs i u e he
p e ious agen cha ac e is ics by an adop ed echnique om so wa e enginee ing
[6] and [9]; e) o e pa allelised ne wo k aining; ) au oma ically gene a e a
eady- o-use ANSI C++ open-sou ce code om he sc een.
The con ibu ion o his pape goes beyond a objec -o ien ed implemen a ion
o ideas. I add esses abili ies, specialisa ions and policies o accomplish speci ic
asks in an Au onomous Agen se ing by using a mul i-s a egy lea ning in o -
de o achie e complex beha iou s. We o e a scalable modelling and pa allel
en i onmen s wi h he pu pose o speeding up beha iou agen simula ions. Fu -
he mo e, he ool is a aluable con ibu ion o use s wi hou knowledge abou
deep p og amming language and lea ning modules because i o e s high le el o
abs ac ion and au oma ic c ea ion o sou ce-code, as obse ed in Sec ion 5.
The es o he pape is o ganised as ollows. Sec ion 2 p esen s an o e iew
o AFRANCI a chi ec u es and how i handles he gene a ed sys em’s modules.
52 Reinaldo F., Siquei a M., Camacho R., Reis L.
Sec ion 3 desc ibes how o design beha iou s uc u es in he in e connec ed
a chi ec u e in o de o achie e he bes agen pe o mance. The use o w appe s
is desc ibed in Sec ion 4. Expe imen s, esul s and discussion a e p esen ed in
Sec ion 5. Rela ed wo k is p esen ed in Sec ion 6. Finally, some conclusions a e
d awn in he las sec ion.
2 AFRANCI Tool
The AFRANCI Tool [6] is a ool buil o e some classes o open-sou ce Py a-
midNe F amewo k [10] pla o m, which ex ends he use o ex e nal lib a ies
o lea ning algo i hms like he WEKA c
lib a y and CN2 induc ion algo i hm.
Py amidNe was es ic ed o a subse o A i icial Neu al Ne wo k (ANN) al-
go i hms whe eas wi h he new abili y o use WEKA c
lib a y and CN2 he
use has access o a use ul eposi o y o machine lea ning algo i hms o da a
p e-p ocessing, classi ica ion, eg ession, clus e ing, associa ion ules and isual-
isa ion.
The AFRANCI ool is composed o h ee main pa s, which a e he G aphic
Use In e ace (GUI), he Machine Lea ning Modules (MLM) and he Au o-
ma ic Open-Sou ce Code Gene a o (ACG). Fi s , GUI is a se o main classes
o handling and modelling lea ning modules, using g aphic elemen s ha will
in e ac wi h he use . MLM implemen s he cons uc ion o he modules using
he chosen lea ning algo i hms. Finally, ACG ecei es a desc ip ion o pic o-
ial ep esen a ion o he sys em s uc u e and p oduces he sho au oma ic
open-sou ce code.
The ool allows use s o design and implemen beha iou -based a chi ec u es
h ough he in e connec ion o elemen a y he e ogeneous con ol modules in he
o m o a ci cui diag am. New s uc u es can be cons uc ed by linking s anda d
s uc u es o modules oge he . This o m is e y amilia o enginee s in digi al
sys ems design and in model analysis sys ems ools (e.g. SIMULINK c
). I makes
some i ems a ailable, such as desk op cons uc o , senso , ac ua o , line links,
skins o lea ning modules, menus, dialogue box. Each g aphical elemen can be
d agged and d opped o a e-sizable sc een and i s ea u es (colou , label, o ma
and size) be adjus ed. He e ogeneous con ol modules a e s anda d boxes wi h
inpu and ou pu o da a. Fo ins ance, i he use is wo king wi h ANN, he/she
has access o a numbe o hidden neu ons, neu on ans e unc ions, aining
pa ame e s e c.
Wi h he pu pose o speeding up he implemen a ion o lea ning modules,
he ool o e s h ee o he impo an ea u es: he mul i pa allel en i onmen ,
he au oma ic ne wo k design o modules and he au oma ic de elopmen o
open-sou ce code. Fi s , each new en i onmen includes a powe ul pa allel e-
sou ce o aining he p oposed designed a chi ec u e. The use can link and
pu oge he se e al sub-p ojec s and un hem, a he same ime because i
is ee o manual schedule . In he design p ocess, once adjus men s ha e been
made, he module is unligh ed and he aining and simula ion can be un again
quickly. The second ea u e is he on sc een au oma ic/wiza d design o ne -
A ool o Mul i-S a egy Lea ning 53
wo ks o lea ning modules by impo ing o CSV (Comma Sepa a ed Values)
iles. When using ANN/WEKA/CN2, he use links s anda d lea ning modules
oge he ; each lea ning module can be simula ed a any le el o abs ac ion o
ine uning o he assembled sys em. The use needs li le knowledge abou i . As
a las s ep he ool p oduces clean and eady- o-use ANSI C++ open-sou ce o
in o ma ion usion, planning and coo dina ion wi h a ew mouse clicks. By using
a high-pe o mance in e p e a ion algo i hm, his unc ional bu compac ANSI
C++ execu able co e is c ea ed om he d awn p ojec . This ANSI C++ code
can be edi ed on sc een in o de o be modi ied and compiled easily in di e en
ope a ing sys ems.
3 Designing a S uc u e
In his sec ion we b ie ly analyse he simple s eps o design, ain and ob ain a
inished sys em composed o di e en lea ning modules.
Fi s , i is necessa y o design he agen ’s s uc u e. The use should plan
how many modules, how hey a e in e connec ed and wha algo i hms o use
in each module. In he nex s ep he use d aws a p ojec in he ool desk op
(sc een). The p ojec mus ha e inpu , con ol modules, ou pu s and links. A e
designing he p ojec , e e y module ecei es he da abase ile ha s o es da a
o eed i in he aining phase.
The in e connec ions a e es ablished be ween inpu s, con ol modules and
ou pu s o make a comple e wi ed ne wo k. The use can connec wo en i-
onmen s: om he ou pu o modules in he i s en i onmen o he inpu o
o he assembled o modules in a second en i onmen . This ool allows he use
o in e connec e e y hing wi hou loss o pe o mance because i uses a pa allel
en i onmen . The use can une each module by changing he de aul module
pa ame e s. Ca e ul is needed in his s ep because a badly planned se up may
lead o he eme gence o w ong easoning p ocesses. This s ep is he only one
ha equi es a li le mo e knowledge abou a anging o modules.
The aining p ocess is simple and consis s o aining and ine uning o
he beha iou -based a chi ec u e o achie e he agen ’s goal. The au oma ic
aining p ocess is esponsible o almos e e y hing and based on he da a
lux sequence o igge modules o aining. Independen ly o he ho izon al o
e ical a chi ec u e le el, he use can ollow he i e a ion aining p ocess o
each module by g aphics, da a windows and o he s.
Finally, he use can gene a e a eady- o-use ANSI C++ open-sou ce o plug
i in he agen . The sou ce code is a codi ica ion o he g aphic modelling. Inside
o his code, use will ind inpu and ou pu connec ions, weigh s, an ac i a ion
unc ions, in he case o ANN, a compac main execu able co e, and some inpu
and ou pu ma ixes. Summing up, hese quick s eps help use o subs i u e
la ge p og ams, ime consuming p ojec s and con using lines o code.
54 Reinaldo F., Siquei a M., Camacho R., Reis L.
4 W appe s
Almos all Machine Lea ning sys ems ha e pa ame e s ha mus be uned o
achie e a good quali y o he cons uc ed model. An expe ienced p ac i ione
knows ha changes in he pa ame e ’s alues may lead o qui e di e en esul s.
To une a sys em’s pa ame e equi es knowledge o he sys em. This is mos
o en a se e e obs acle o he wide sp ead use o such algo i hms.
As p oposed by John [11] one possible app oach o o e come such a si ua ion
is by he use o a w appe . A w appe p oduces se e al models using di e en
combina ions o he lea ning algo i hm and e u ns he “bes ” model. In ou ool
he w appe op imises he es se e o a e es ima ion. This au oma ic uning
o pa ame e comple ely hides he de ails o using he lea ning algo i hms om
he use . I is he e o e a way o make he ool usable by a wide ange o use s.
When he o al numbe o combina ions o pa ame e ’s alues is small3 he
ool ies all he combina ions and chooses he bes one. When he numbe o
combina ions is la ge he pa ame e s a e uned using a Gene ic Algo i hm (GA)
[12] wi h mu a ion and c oss-o e GA ope a o s. Fo he ANN we also choose
au oma ically hei s uc u e. A GA is used o choose he bes numbe o hidden
laye s and numbe o neu ons in each laye o each ANN. The ype o ANN is
also included in he au oma ic choice.
As u u e wo k we in end o ex end he use o w appe s o do ea u e (subse )-
selec ion as in [13] and [14]. This acili y would equi e howe e a igh e ela ion-
ship be ween he modules syn hesis and hei in e -connec ion. I he w appe
decided ha some ea u e is no ele an o he classi ie hen ha inpu would
ha e o be emo ed in he modules in e -connec ion design s age.
5 Expe imen s
To illus a e he ea u es o AFRANCI and acili a e he eade ’s unde s anding
we gene a ed a simple a i icial p oblem and da ase in he RoboCup Rescue
se ing. The p oblem we de ised is o decide i a ambulance o i eman should
escue o no a ci ilian o a nea es e uge. The ci ilian is somewhe e in a bu ning
building. The decision is commonly made based on he localisa ion and agen ’s
and ci ilian’s li e condi ions. The main independen a iables include: he posi-
ion (X, Y) o he ambulance, i eman, building on i e, i e b igade, he nea es
e uge ( escue building), and o he ci ilian; he li e condi ion measu e o he
i eman and ci ilian 4, he building ola ile in o ma ion is composed o ea lie
bu n , s a e and s uc u e; he s a e o he ambulance (busy/ ee) o ecei e he
ci ilian and o he i eman (busy/ ee) o ex inguish he i e o o escue he
ci ilian; a measu e ha assesses he di icul y o he ci ilian escue si ua ion.
The sys em de ised is composed by se e al modules ha encode he deci-
sion o he i eman and he ci ilian and pa icula ly a main module o combine
i eman and ambulance decisions. Figu e 1 shows he modula s uc u e o he
3In he cu en implemen a ion small is less han 20.
4A measu e be ween 0 and 100 o he ene gy he i eman can use.
A ool o Mul i-S a egy Lea ning 55

Fig. 1. A chi ec u al Design.
sys em cons uc ed in e ac i ely by he use . No pe cei ed in he igu e is he
he e ogenei y o he modules. Di e en modules use di e en ep esen a ions
sand whe e induced using di e en lea ning algo i hms. Re e ing o he mod-
ule’s labels in Figu e 1 he ollowing algo i hms we e used. The Ci ilian module
was cons uc ed using AFRANCI buil -in eed o wa d ANN. The Ambulance,
BuildingOnFi e, Fi eman and RescueFi eman modules we e cons uc ed using
CN2 ule lea ne . The o he modules, Building and Decision, we e cons uc ed
using WEKA’s J48 Decision T ee algo i hm. The use had only o selec he
numbe and place in he window o he modules, o connec hem and choose
inpu and ou pu a iable names. All his was done using d ag-and-d op ope -
a ions. He hen p o ided he da ase and he ool ained he modules in he
co ec sequence and gene a ed a C++ p og am ha encodes he sys em.
56 Reinaldo F., Siquei a M., Camacho R., Reis L.
J48 p uned ee
------------------
ambulance_ap = TRUE: RescueAmbulance
ambulance_ap = FALSE: RescueFi eman
IF occupied = occupied
THEN class = n [52 0]
ELSE
IF ci ilian = no ap
THEN class = n [20 0]
ELSE
IF Yamb > 8164.50
AND Xci < 9204.50
THEN class = y [0 7]
ELSE
IF Yamb > 340.00
AND 386.00 < Yci < 7731.50
AND X e uge > 3800.00
THEN class = n [9 0]
ELSE
IF Yamb < 5721.00
AND X e uge > 866.00
THEN class = y [0 8]
ELSE
(DEFAULT) class = n [4 0]
a) b)
Fig. 2. a) Decision T ee gene a ed by WEKA’s J48 lea ne . b) Rule se gene a ed by
CN2.
The ac ion o deciding which agen will be esponsible o escuing he inju ed
ci ilian is aken in he Decision module (see Figu e 1). The i eman agen will
pe o m a escue ac ion only i he ambulance agen will no be able o do so.
In he case o bo h, he i eman and ambulance, a e capable o escuing he
ci ilian, he module decides in a ou o he ambulance agen because a i eman
agen has o ex inguish i es in bu ning buildings wi h he aim o p ese ing he
ci y. In o de o check i he ambulance is en i ely ap o escue a ci ilian (see
Figu e 2) he ules induced by CN2 es ablish ha : ( ule 1) i he ambulance is
occupied hen i is useless o a emp he escue; ( ule 2) i he ci ilian has no
enough “ i ali y” hen i is also no escued; (o he ules) he ci ilian will be
escued i i has enough “ene gy” and he ambulance is be ween he ci ilian and
he escue place o he wise i will no be escued.
6 Rela ed Wo k
In o de o de elop a obus ool, we analysed wo ele an ones. The Ma -
Lab c
and SIMULINK c
 ools a e mainly conce ned wi h he o e o a de ailed
design o a con ol p ocess [15] and o au oma ically gene a e a eady- o-use code
o i . Howe e , ha ool has wo main limi a ions ha a ec he design o he
whole p ojec . Fi s , he use canno design a complex s uc u e composed o se -
e al he e ogeneous modules no a in e connec ed a chi ec u e because he ool
A ool o Mul i-S a egy Lea ning 57
does no o e acili ies no a speci ic mul i-en i onmen o wo k wi h. These
limi a ions inhibi he use ’s abili y o handle di e en le els o abs ac ion,
se e al p ocesses in he same en i onmen . Second, he eady- o-use code was
gene a ed om a simple lea ning algo i hm is la ge o be wo ked, complex o be
unde s ood and unp ac ical o be used. O he s udied so wa e simula o was
he SNNS c
(S u ga Neu al Ne wo k Simula o ) [4] [5] ha i exclusi ely
wo ks wi h ANN in o de o c ea e hei applica ions. Al hough he ool o e s a
good g aphic en i onmen , i s epe o y is limi ed o only a beha iou le el a a
ime, wi hou o e ing a pa allel en i onmen o ain he ANNs. Mo eo e , i is
limi ed conce ning expandabili y o new ways o g aphically p e iew he whole
s uc u e ha is being wo ked wi h.
In Sec ion 2, we p esen ed he ool which o e s a use iendly pa allel g aphic
en i onmen ha acili a es he de elopmen and aining o Modula and Hie -
a chic Sys ems by including se e al modules wi h di e en lea ning algo i hms.
The sys em a chi ec u e p oduced wi h he AFRANCI ool p omo ed he Mul i-
S a egy lea ning as long as a ious lea ning modules a e used o compose he
s uc u e.
7 Conclusions
In his pape we desc ibed a ool o he de elopmen o Mul i-S a egy lea ning
sys ems. Using a iendly g aphical in e ace he use may de ine he modula
s uc u e o he sys em and choose he lea ning algo i hms o cons uc each
module. He hen p o ides he da ase and le s he ool ain, in he co ec se-
quence, each module p oduces a comple e sel con aining p og am encoded in
he C++ language.
The ool p o ides se e al lea ning algo i hms and is able o call ex e nal
lea ning algo i hms o cons uc he modules. The deploymen o he ool con-
i med he assump ion ha i was easy and as o de elop Mul i-S a egy sys em
wi h AFRANCI.
As u u e wo k we in end o de elop w appe s (John, 1994b) o au oma ically
une he modules pa ame e s, op imising he es se e o a e es ima ion.
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