Embedding o ma i e assessmen ea u es in o LabView in e aces
REV 2007 - www. e -con e ence.o g 1
Embedding o ma i e assessmen
ea u es in o LabView in e aces
Max Con adi1, Reinha d Langmann1, An ónio M. Ca doso2, J. M. Fe ei a2
1 Uni e si y o Applied Sciences, Dusseldo , Ge many
2 Faculdade de Engenha ia, Uni e sidade do Po o, Po ugal
Abs ac — Vi ual ins umen s (VI), namely hose designed
using LabView, a e inc easingly used o enable access o
emo e ins umen s o e he web. In an academic con ex ,
such VIs may be used o build a emo e wo kbench ha
enables he s uden s o ca y ou a labo a o y ask om
hei homes. Remo e wo kbenches, o simula ion
en i onmen s, a e no mean o eplace eal labs, bu a he
o complemen hem. They enable he s uden s o con inue
hei wo k in he lab, e en a e lea ing he uni e si y
campus. In mos cases, a emo e wo kbench cons i u es a
eplica o wha he s uden sees in a eal wo kbench.
Howe e , VI in e aces may be designed o p o ide a much
iche educa ional expe ience, namely by embedding
o ma i e assessmen ea u es, as desc ibed in his wo k-in-
p og ess pape .
Index Te ms— e-lea ning, o ma i e assessmen , online labs,
LabView.
I. INTRODUCTION
The objec i e o his wo k is o design embedded
assessmen ea u es in o common VIs, used o build
emo e wo kbenches in academic con ex s. An embedded
assessmen ea u e may be seen as a VI ex ension ha
cap u es and s o es o ma i e assessmen in o ma ion,
desc ibing how a s uden handles an ins umen . This
in o ma ion will be made a ailable o he s uden and o i s
eache , and may be used o iden i y a eas whe e he
s uden skills / knowledge need o be imp o ed.
The pic u e below illus a es a emo e wo kbench ha
was de eloped o suppo labo a o y assignmen s in digi al
/ analogue elec onics. This emo e wo kbench comp ises
an oscilloscope, a wa e o m gene a o , and a mul ime e ,
besides li e images om he lab.
Figu e 1. A emo e wo kbench suppo ing basic elec onics expe imen s
The s uden s unning an expe imen will ha e o adjus
he wa e o m gene a o and he oscilloscope. I his was
done in a eal lab, wi h a u o nea by, he/she would be
able o assess i he s uden knew how o handle hese
ins umen s, jus by wa ching how he s uden ca ied ou
his i s s ep. The objec i e o his wo k is o s udy how
a he same conclusion can be de i ed by au oma ically
moni o ing how he s uden handles he VIs.
II. REFERENCE MODEL
The PTSE lab a FEUP al eady uses a ious VIs ha
a e used o design emo e expe imen s in elec onics. All
such VIs we e de eloped using LabView. The p oposed
app oach consis s o analysing he LabView sc ip s o
such VIs and de ising ways o iden i y and cap u e he
ele an embedded assessmen in o ma ion. In he ini ial
phase o his wo k, a simple VI ep esen ing a basic
ins umen (e.g. a ol me e ) was used o look o an
app op ia e de elopmen model and i s implemen a ion
s a egy.
Only a ew s uden ac ions a e ele an om he
assessmen poin o iew. One o he i s ques ions o be
conside ed was he e o e how o iden i y wha ac ions
should be logged in o he assessmen epo . On he o he
hand, a gi en ac ion may o may no be ele an ,
depending on he ope a ing condi ions a ha momen , and
on wha he s uden may be ying o achie e. The ules
ha iden i y when a gi en ac ion is ele an o
assessmen pu poses a e he e o e dynamic and mus be
con inuously upda ed as he expe imen p og esses.
Le ’s conside he example o an oscilloscope VI whe e
one channel is being used o obse e a gi en inpu signal.
The V/di and ime base bu ons de ine he display
condi ions, and need o be adjus ed by he s uden in
acco dance wi h he ampli ude and equency o he inpu
signal. A 5 V / 1 KHz sine wa e may be isualised by
adjus ing he display channel o 2 V/di and he ime base
o 100 μs/di , al hough he e a e o he se ings ha migh
as well be selec ed in his case (e.g. he same V/di scale
and a 50 μs/di ime base, o any o he neighbou ing
ampli ude and ime base scales).
The accep able anges o V/di and ime base se ings
a e he e o e dependen on he inpu signal, and may be
ep esen ed as shown in igu e 2, whe e each ange is
de ined by a lowe and a highe limi , de ining a do ed
a ea ha ep esen s he success space. No ice ha he
success space may be n-dimensional in mo e complex
examples, o uni-dimensional in e y simple cases (such
as he ol me e VI e e ed abo e).
Embedding o ma i e assessmen ea u es in o LabView in e aces
REV 2007 - www. e -con e ence.o g 2
Ampli ude scale
Time base scale
Time / di
lowe bounda y
Time / di
highe bounda y
V / di
highe bounda y
V / di
lowe bounda y
Figu e 2. Gene ic ep esen a ion o a possible success space
An assessmen e en is igge ed when he s uden s a e
asked o calib a e he oscilloscope channel. Reaching he
success space (and s aying he e) in less han 20% o he
ime a ailable o aking mo e han 100% o ha ime o
ge he e, will gene a e o ma i e assessmen in o ma ion,
which will be added o he assessmen epo . Any e en
ha adds in o ma ion o he assessmen epo is a alid
assessmen e en . When he s uden eaches he goal o
he assessmen e en wi hin 20%-100% o he ime
a ailable, no assessmen in o ma ion is p oduced. I he
s uden is asked o calib a e he display channel bu is no
able o selec V/di and ime base scales wi hin a gi en
ime pe iod, his may mean ha his/he skills need o be
imp o ed. On he o he hand, i hey each hei goal e y
quickly (e.g. in less han 20% o he ime a ailable), hen
his may be indica i e o a e y good s uden . In bo h
cases, he assessmen e en should p oduce assessmen
in o ma ion. The ac ions pe o med by he s uden s (i.e.
any in e media e se ings selec ed while ying o calib a e
he oscilloscope) du ing a alid assessmen e en shall
also be eco ded in he assessmen epo .
Ampli ude scale
Time base scale
Time / di
lowe bounda y
Time / di
highe bounda y
V / di
highe bounda y
V / di
lowe bounda y
S a poin
Fi s ac ion (ano he
V/di se ing selec ed)
Las ac ion be o e
100% o ime elapsed
Figu e 3. Failing o each a success ul ou come
The example on igu e 3 illus a es a case whe e he
s uden ails o achie e he goal o calib a ing he
oscilloscope channel, wi hin he ime a ailable o do so.
No ice ha his conclusion is ques ionable, since he/she
eached he success space in ime, and migh jus ha e
modi ied he V/di scale o show some hing o a
colleague. Howe e , and since many assessmen e en s
will be igge ed as he expe imen p og esses, imp obable
si ua ions as he one jus desc ibed a e no expec ed o be
s a is ically meaning ul.
III. TECHNICAL IMPLEMENTATION
The cases conside ed in he p e ious pa ag aphs
indica e he need o de elop embedded assessmen
e e ence models, able o p o ide an abs ac
ep esen a ion o he equi ed assessmen ea u es. Such
e e ence models will be speci ic o each VI, desc ibing
hei own n-dimensional success spaces, indica ing wha
(dynamic) in o ma ion de e mines he success space
bounda ies, he ime pe iod associa ed wi h each
assessmen e en , he in o ma ion o be added o he
assessmen epo in case o a alid ins ance, e c.
Once a e e ence model ha desc ibes he embedded
assessmen ea u es o a gi en VI is eady, i is possible o
s a i s echnical implemen a ion. Since he VIs ha a e
a ailable a he PTSE lab we e buil using LabView, he
eques ed embedded assessmen ea u es is bes done in
he o m o a LabView VI assessmen ex ension.
Assessmen ex ensions should be de eloped in modula
o m, meaning ha each VI may exis wi h o wi hou
hem. Embedded assessmen ex ensions a e no
necessa ily isible a he VI in e ace le el, bu he s uden
should always be awa e o hei p esence.
Figu e 4. A VI and i s assessmen ex ension
Ou i s implemen a ion goal consis ed o eco ding all
s uden ac ions and ma king all s uden -d i en e en s, as
shown in igu e 4. The assessmen ex ension adds a
con ol panel a he o iginal VI bu on, enabling he u o
o iden i y hose momen s in ime whe e meaning ul
e en s may be loca ed. The u o is able o eplay a
no mal speed he whole expe imen , o o as o wa d a
a ious speeds. He/she may also jump di ec ly o he
momen whe e a gi en e en is ma ked.
IV. CONCLUSION
The cu en implemen a ion is able o eco d all s uden
ac ions and o iden i y he possible meaning ul momen s
o assessmen pu poses, bu is s ill missing he au oma ic
assessmen ea u es. The inal p o o ype will be able o
help u o s and s uden s o ob ain o ma i e assessmen
in o ma ion, which can be used o iden i y any a eas
whe e u he aining is equi ed. No ice ha eco ding
s uden ac ions may aise e hical issues which ha e o be
discussed be o ehand and he s uden s mus be awa e o
i s p esence. In pa icula , i is impo an o ensu e ha all
s uden s a e awa e o he embedded assessmen ea u es
and in ag eemen wi h hei use.
Embedding o ma i e assessmen ea u es in o LabView in e aces
REV 2007 - www. e -con e ence.o g 3
REFERENCES
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AUTHORS
M. Con adi is wi h he Uni e si y o Applied Sciences,
Depa men o Elec ical Enginee ing, Jose -Gockeln-
S asse 9, D-40474 Duesseldo (e-mail:
maxcon [email protected] ).
R. Langmann is wi h he Uni e si y o Applied
Sciences, Depa men o Elec ical Enginee ing, Jose -
Gockeln-S asse 9, D-40474 Duesseldo , (email:
einha d.langmann@ h-duesseldo .de).
A. M. Ca doso, is wi h he Faculdade de Engenha ia,
Uni e sidade do Po o, Rua D . Robe o F ias, 4200-465
Po o, Po ugal (e-mail: admp se@ e.up.p ).
J. M. Ma ins Fe ei a, is wi h he Faculdade de
Engenha ia, Uni e sidade do Po o, Rua D . Robe o
F ias, 4200-465 Po o, Po ugal (e-mail: jm @ e.up.p ).