Document Sample
APPLICATION Powered By Docstoc
					'   I



        M.A.Laughton, R.N. Adams,                  A. Taylor, A. Hawken

        Q m Mary & Westfield College,             AIlT Limited
        University of London.

    AI3SmAa                                                            instnrcturerathsthanproblemoriented. Inorderto
                                                                       promote the developmeat of the Single European Market
    Despite the success with the use of computers in the               andtheharm~ofpractices,installers,~
    power indushy, there remains a large class of problems             equipment manufecture~ Trade Unions all have an
    that eludes solution using conventional software. These            interest in the intelligent, expertisGdriven inteqnetation
    problems are usually solved by experts, requirejudgment.           of swh standards regardlem of C0"y of langoage (1).
    basedon experience gainedoveraperiodof timeand
    involve imprecise knowledge that cannot be formulated              At present the application of the DEE W h g
    into an algorithm or a mathematical model.                         regulations, are suplxnted by a variety of further
                                                                       publications and specifictypes of software to help in
    The inteqnaation and application of the IEE wiring                 cable selection. circuit design, circuit analyses. In
    regulations is just such a problem concerning the                  addition useful wining courses and important
    application of a complex set of rules, proceduresand               complementary services have been developed. (2) Such
    standards, which, by reason of their format, are not easy          products and services have been primarily developed in
    t apply to specifc problems. As such they provide an
     o                                                                 the 8', reflecting the increasing need to help
    ideal example of an a m of work where expert systems               support and train engineers to most effectively
    can assist in the engineeringdesign of electrical                  u-
                                                                        n         and apply the regdatcq standards.
                                                                       Nowadays with the availability of expert s s e s m k ,
    Past work in the development of a prototype expert                 which have the general ability to npresent the knowledge
    systems shell will be summarised including the main                ofthe human expert and to simulate deductive and
    featuresof the system. An example consultationsession              reasoning processes. there is a case far considering
    concentratingon the regulations collcemedwith isolation            whether all such training and intepetive functions could
    and switching will be given. It is concluded that the              not be assumed by such knowledgebased information
    initial results are sufficiently encouraging to justify            technology. Present expert system tools, have the
    c o n s i d e " of a full implementation of the regulations        ability to access,manage and communicate efficiently
    in this form. A suitable smcture of a proposed expert              with the engineer and related databa~,  graphics.
    system for practical indushial use will be presented.

                                                                       windowq scientific and text software,thus they o f r new
                                                                       and powerful means for informationmanagement and its
    The paper concludeswith consideration of a number of               interpretation.
    commercial options concerningrun-time licences. the use
    of compiled knowledge bases and text, Copyright and
    discuss the benefits the industry could dexive f o the          =A
    application of such tools.

                                                                       m l y the first andindeedonlydirect application of
    BACKGROUND                                                                                E
                                                                       expert systems to the J E Wiring Reguhtkm began in
                                                                       1985 through Queen Mary College. University o   f
    Under the Single European Act the installation of                  London (4-6). when the first generation of eqefi
    equipment and servicesin any EC country may be carried             systems tools were coming onto the market. The IEE
    out by competent persons from another EC country.                  Wiring Regulation 15th E i i n 1981. were the subject
    Vbrk is governed usually by Regularionssuch as                     of investigation because the new IEC famat lent itself to
    BS7671:1992. the Electrical Wiring Standards in the                a logical bnxkdown of the task into identifiablespecialist
    UK. T e style of such Standards arranged according to
           h                                                           areas. The areas of switching and isolationwere chosen
    the format of the International Electrotechnical                   for examination.
    Commission (IEC) has resulted in such publications
    being criticised for their impenetrability, being axiomatic


Theapproachusedwasto                                             to the switch normally used for conmhg the circuit,
- consider the "kno~ledge"contained in such ~ g d & m            (ii) effective local means for the isolation of the circuit
-constluctaprototypeknowledgebase                                frw the supply such means being a d d i t i d to the
- conduct tests on the prototype                                 switch normally used for controlling the circuit,
                             . essoftheknowledge
-reach views on theappropnaren                                   (iii) a switch having a lock or removable handle, o a r
b0serepresentation.                                              disbibutionbwrdwhich can be locked,in either case
                                                                 complying with regulation 476-4.
?he expert system selected was a text animation tool
ESP Advisor, because of the Comparative ease with                    -
                                                                 S Is an isolator being used in conjunction with a circuit
which it could be used to display text selectively               breaLer? R - N O
through consultation with an Enginea Consequently                S - Is discharge lighting located externally ? R - NO
the system functionedby selectively displaying text and
questioning the Engineer. The objective was topresent            S - Is discharge lighting located internally ? R -YES
the user with the regulatiom relevant to his needs. In
additionthe system had abrowse mode which on demand              (iii For interior installations,the switch shall be in the
would display the full reguhtbns with exphatory                  main entrance to the building or in anotherposition to be
notes. An example of the inmactive text and                      agreed with the local fm authority.
informationusedisshown atTABLE1. Theideawas
to display the full text of the legIdaions as the primary        NOTE: wherever practicable, all interior installationson
outplt of the system, using the *as         "expfxIs"in          any one building should be conIroUed by a single
choosing suitable questions to put to the usec in o&r to         firemans switch.
determine which particularregulationsare relevant to the

                                                                 liedimensionsof the knowledge base were limited to
                                                                 the 88 regulationswhich c o v e d Isolation and
E         u       !   L   l   i   l   i   I   b   P              Switching. The detail of the knowledge base consisted of
                                                                 215 paragraphs with 104 parameten. This was the
System S Engineers Response R         -                          limitationsofthe available hard-    and expert systems
                                                                 took in 1985 which could not cope with al 550
S - What type of electrical system is being used?                regulationsin the 15th Edition of the IEEWiring
(1) - TN-C  (nemal& protective funuions c o m b i i
throughout the system)                                           The factthat theprototype couldnotproducea
( )- TN-S (mad& protective conductorsseparate
 2                                                               "complete" system is of course. not an issue b c u e it
throughout)                                                      was onlyexpectedtobea demons"and assessthe
(3) TN-C-s( n e d & ptective conductorspertially                 expert systems approach. In this context, the d u e of
combined)                                                        the demonseator, which was the fmt of its kind in
(4) - Tr(1pointofsourcedirectlyeanhed:independent                relatingexpert systems techniques t the D E Wiring
                                                                                                    o       E
earthing)                                                        Regulatioas, demonsmated that the applicationof
(5)   - IT (no direct connection between live parts &            expert systems techniques was justified.
                                                                 Today PC's and indeed expert systems tools can be
S - Enter the number of the relevant entry: R - 2                loOthxfaster, and readily portable. Whatcanbe
S - Is high voltage discharge lighting in use? R - YES           classif& as 2nd Generation expert systems tools are
                                                                 available which can:
Reg. 476-6 applies (7)
For elecaic discharge lighting installationsusing an             -   reactinrealrime
open-circuit voltage exceeding low voltage. one or more          -   handlealargenumberofpammtenanddes
of the following means shall be provided for the isolation       -   be open to the outside World
o every self-
 f                     l"ire, or dteanatively of                 -   befasttoimplement
every circuit supplying luminairesat a voltage exceeding         -   beeasytosuppatt
low voltagc                                                      -   have security, nliibility and stability

(i) m interlock on a selfantainedluminaire, so arranged          with the above capabilities t e working requirements
that before access can be had to live parts the supply is        can be sstisticd (5).
The above model directlyrelatedtospecificsectionsof
the IEE Regulations as shown

                                                                 R - Domestic

                                                                 S -Whatsortofinstallationereyoudoing?
                                                                 Appliance? MainFe&? Circuit?
 E*--                    Regulations
                  I   Knowledge Base                             s -what best describesthe naRrre of the task?
                  I                                              Kitchen?Bah”?GeneralHousebold?~High
             Questions                                           Power? 110 reply
The Future model will augment the model by firsty                S -Will therebe hot surfaces suchasa“?
consulting about the tasks that an Engineer is wig               Yes? No?
expected to carry out:                                           R-Yes

Engineer---w     Elicitation    __--_--__----
                                Regulation                       s -willthere be water?
           I KnowledgeBase I KnowledgeBase                       Yes? No?
           I                 I                                   R-Yes
      Questions        Dynamic Regularions Analyses
                                                                 S Will there be devices requiring > 13Amp?
                                                                 Yes? No?
The ‘Risk Elicitation Knowledge Base (TEKB) focuses              R-Yes
on the users t s s from the E n g i ” job specifiion.
It asks i i i l questions about the job that the engineer
         nta                                                      -
                                                                 S What voltage me we dealing with?
is doing, from these the s s e is able to make some
                            ytm                                  240 Volt? High Voltage? Low Voltage?
assumption about what is and is not going to be                   -
                                                                 R 240 Volt
involved in the task. These assumptiom am rhen
checked. For example, if an Omce block is being wired
then regulations pertaining to agricultd installations
can be ruled out. The knowledge base builds up a
general picture or workingpmfde. it does not itself check        S -Lighting l)pe Discharge?
the regulations. nor does it need any a c t
                                       c me                      Yes? No? Unknown?
representation of them.                                          R-NO

The resulting task pmfde is used as an input to the                -
                                                                 s Appliance status Fiied?
second stage of the knowledge base system. This is the           Yes? No? Unknown?
Regulation Analyses Knowledge Base. This knowledge               R-Yes
base contains an axiomatic representation o the semantic
contents of the regulations. and the knowledge of how t o          -
                                                                 S Appliance directly m t e d ?
use the minimum of information F r h r questions
                                    ute                           e?
                                                                 Y s No? Unknown?
cova the regulations completely and discover which can           R-NO
be definitely ruled out and which ~maining  regulations
ShouldbepresentedtotheuSecTABLE2providesan                       S - Isolatorremotefrom equipment?
example of the questioning.                                      Yes? No?Unknown?

                                                                 S - Circuit Brealrer required
                                                                 Yes? No? Unknown?

                                                                 Display of paragraphnumbers of the Regulations r q
                                                                 for the Engineer to cany out his work:
System S Engineers Response - R
                                                                 P476-2, P476-3, P476-4. P476-7, P476-8. P476-11,
                                                                 P476-18. P476-19

S - In what environment is the work being carried out?
Domestic? Canmercial?Mustrial?Agricultural?


Ihc a m is simply to use the knowledge of an
      i                                                                                               it
                                                                 Asanalternativemodcofapuation is interesting to
e x p e x h d "competent person" to s e k t                      speculateon whethex users of such regulationswould
those paragraphs.pagesandtablesofdata, whichare                  prefer to use an Expert System fur a c s viaa " i
                                                                                                     ces          a
appmphe. At this stage the method of providing                   bureaufacility. Such apractice in other areas such as the
furtherdetailedinfo". neitherelectmnhllyonscreen                 Lexisdatabmeservicesin theunited States which is
~ViahWd~needScarefulconsideration.                               consulteddaily by the legal professkm in many countrks
                                                                 including the UK.
This two stage approach. BS shown at Fig 1, below
proVidesthebenef-@Of p n x q. m f questionsand
                                 m                               Copywriterequirementswouldimposeafurther
answer session. with a coherent line of questioning. and a       constraint on the security of information. Floppy

~p~searchappmchtodelivercompletmess                 with         dislrs would have to be software or be ptected with
themini" effort. Thisisalitklikeusinganindex                     hardware dongles. B l n e a u ~ a r e v ~ a n d
t look upevery ref-
 o                         and cross~€mceeveryteam               involve security practises common to any computer
that is encounlered to evaluate the applicability of each        hstallationaccessible to the outside world.
new item. It is a task that the computer can do very
well,and v e y quickly, but which would take a person
with a manual and an index,a very long time, and they
would probably miss something.
                                                                 The use of Expert Systems will improve the utility and
                                                                 application of Regulationsand Standards in the practice
                                                                 0fEngineeriOg. Immediateadvicebesedonknowledge
                                                                 of expexienced practitioneas will be available instantly to
                                                                 relatively i n e x p e r i d personnel. The potentialof
                                                                 such recently developed tools in the fE1d of Artificial
                                                                 Intelligencehas been demonstrated in other applications.
                                                                 Such are their obvious b f @that their use is
                                                                 electronic publishingand their intaprCratcm of complex
                                                                 near fuape.

                                                                 1. Simmonds R "Make ReguWons Statutory says
                                                                 ECA." EleceicalReview MadJa~~1y-4thFebrusry
                                                                 2. IEEGuideto SofhvarefortheIEE Wiring
                                                                 Regulations. June1992
                                                                 3. Rikkonen. T A m l a T               J "An
Finally it is necessacy to consider a number of practical        Intelligent RXt-Based Information M " t system
computer related issuesifusersaretocoasult                       fur safety Regulations" Proc. " .
                                                                                                4       Conf.,
Regulations using expert system tools. Firstly such              Melbourne. Jan 4-8.1993. pp 455-460
sse should be capable of use via the standardFC
 ytm                                                             4. Laughton M.A. Adams R.N..Electricity Supply and
type wmputas found in engineaing / contntctofi o f c s
                                                    fie                                 -
                                                                 Equipment Installation Regulatiolrp and SEandards
and be able to be loaded using s l installing floppy
                                 ef                              KnowledgeBases. Intemal Repoa, Departmentof
discs. Nofurther training ofthe mer either in terms of           Electronic Engineering,Queen Mary College.
use of eapert system or in the application of the                University of London Jan 1988
Regulationsshould be required.                                   5. 'bylor A, HawkenA Laughton MA.
                                                                 The Use of Knowledge Based Systems in Delivering Real
CD ROM based systems and multimedia applicationsin               -Time Plant Protection and Safety. Proc. ESAP 4.
g e d arebecomingmorepopularandthehadwareis                      Conf.. Melbourne, Jan 4-8.1993, pp 440-443
more widely available. whether oc not photo quality              6 Clifford J.S.. Adams, RH.. Laughton, M.A.." A
pictures and animation is arequhmentfor this type of             Prototype Wiring RegulationsKnowledge Base"Jntemal
w& is a moot point; however hypertextbased browsing              Report, Department of ElectronicEngineming, Queen
facilities for the study o text and associated documents
                          f                                      Mary College, University of London 9/85.16pp.
might well be attnrctive.                                            E
                                                                 7. J E Wiring Regulations, 15th Edition 1981.

Shared By: