Ingen bildrubrik

1
Portable Automotive Electronic Modelsusing
Standard XML Technologies
Syed Zia Akbar Zaidi
Department of Computer and Information
ScienceLinköpings universitet
2
Contributions

• Defined a simple architecture definition language
  (ADL)
• Used to model the automotive electronic systems
• XML representation models portable among
  manufacturers and suppliers
• Identified the constraints of the automotive
  electronic field
• Types of requirements
• Modelling and representation of automotive
  electronic requirements using XML technologies
• Xlinkit, XQuery, CommonRules
• Case study representing a vehicle cruise
  controller
• Modeled using our ADL
• The requirements placed on the cruise controller
  have been modelled using xlinkit, XQuery and
  CommonRules

3
Outline

• Automotive Electronics ? The Industry ?
  Generic Architectures ? The Cruise Controller
• Modelling AE using XML ? The Merits of
  XML ? The Cruise Controller Model ? The
  Cruise Controller
• Requirements Modelling ? Requirements on the
  Cruise Controller ? XML Technologies ?
  Xlinkit, XQuery, CommonRules
• Conclusions and Future Work

4
Embedded Systems

• Automotive Electronic Systems
• Complex distributed embedded systems that have
  important requirements safety cost, and
  performance.
• Responsible for controlling the functionality of
  a vehicle.

5
Automotive Industry Interoperability
6
What is an ADL?

• An ADL is a language that provides features for
  modeling a hardware and software systems
  conceptual architecture.
• In other way, it is a high-level description of
  the overall interconnection structure of an
  architecture.
• It provides formal modeling notations for
  architectural elements, such as components,
  connectors.
• It also provides development tools that operate
  on architectural specifications, such as
  configuration and constraints.
• It reduces cost of development.
• ADLs
• Software ACME,Rapide, C2, Darwin, MetaH, SADL,
  UinCon, Wright, xArch,
• Hardware MoML, ISDL, Valen-C, MIMOLA, LISA,
  nML, ARC, Axys, RADL, Target, MDES, EPRESSION,

7
ADL Exchange The Merit of XML

• XML highly suited for ADLsThe Merit of XML as
  an Architecture Description Metalanguage, Steve
  Pruitt et al.
• Representation
• Analysis
• Traceability
• Views
• Collaboration
• Repository

lt!-- Example in MOML --gt lt?xml version"1.0"
standalone"no"?gt lt!DOCTYPE model PUBLIC ""
"http//"gt ltmodel name"top" class"path name"gt
ltentity name"source" class"path name"gt
ltport name"output"/gt lt/entitygt ltentity
name"sink" class"path name"gt ltport
name"input"/gt lt/entitygt ltrelation name"r1"
class"path name"/gt ltlink port"source.output"
relation"r1"/gt ltlink port"sink.input"
relation"r1"/gt lt/modelgt
8
AE Generic Architecture
9
Cruise Controller
Process Start WCET Resource PR1 0 0
P6 PR2 0 12 P1 PR28 0 12
P2 ARC2 12 1 B1 PR3 13 7
P2 .. .. ..
10
XML Model for Cruise Controller

• architecture.xml
• ltNODE Name"CEM" Id"P1"gt
• ltProcessor Name"AMD"gtltP_TypegtIlt/P_Typegtlt/Process
  orgt 
• ltMemory unit"KB"gt128lt/Memorygt
• lt/NODEgt
• behaviour.xml
• ltPROCESS Name"PR3" Id"PR3"gt
• ltWCET unit"ms"gt7lt/WCETgtltMemory
  unit"KB"gt2lt/Memorygt
• lt/PROCESSgt
• ltARC Name"ARC3" Id"ARC3"gt
• ltSrcgtPR3lt/SrcgtltDestgtPR4lt/DestgtltDelay
  unit"ms"gt0lt/Delaygt
• lt/ARCgt
• mapping.xml
• ltMAP Resource"P1"gt
• ltProcessgtPR1lt/ProcessgtltProcessgtPR2lt/ProcessgtltProc
  essgtPR30lt/Processgt
• lt/MAPgt
• schedule.xml
• ltSLOT Id"PR1"gtltStart unit"ms"gt0lt/StartgtltDuration
  unit"ms"gt0lt/Durationgt  
• ltResourcegtP6lt/Resourcegtlt/SLOTgt

11
Requirements Engineering

• RE is the branch of systems engineering
  concerned with
• the real-world goals and constraints on systems
• the relationship of these factors to precise
  specifications of systems behavior, and to their
  evolution over time and across system families.
• RE Activities
• eliciting requirements
• modeling and analyzing requirements
• communicating requirements
• agreeing requirements
• evolving requirements

12
Requirements on the Cruise Controller

• Requirements on the model
• The model should be consistent
• Every process should be mapped to one and only
  one node
• Every sensor/actuator should be connected
• The schedule should be correct
• The schedule should respect the precedence
  constraints
• No two slots in the schedule should overlap
• Cruise Controller
• Timing requirements
• The CC should execute within 100 ms
• Resource requirements
• The sum of processes memory on a nodeshould not
  exceed that node's capacity
• Should be expressed using XML Technologies

13
XQuery An XML Query Language

• W3C standard
• http//www.w3.org/TR/xquery
• Derived from QuiltJonathan Robie, Don
  Chamberlin, and Daniela Florescu
• Based on XML-QL
• Relevant W3C documents
• XML Query Requirements
• XML Query Use Cases
• XQuery 1.0 An XML Query Language
• XQuery 1.0 and XPath 2.0 Data Model
• XQuery 1.0 Formal Semantics
• XML Syntax for XQuery 1.0 (XQueryX)

14
XQuery

• To find all process names and connected sensors
  for processes whose worst case execution time gt
  10ms memory size lt 20MB.
• ltBehavioral_Modelgt
• for b in document(Behavior.xml)//Process
• where b/WCET gt 10 and b/Memory lt 20
• return
• ltProcess Name b/Namegt
• b/Sensor
• lt/Processgt
• lt/Behavioral Modelgt
• Overview
• Path expressions XPath
• Conditional expressions
• FLWR (flower) expressions

15
XPath

• W3C Standard
• http//www.w3.org/TR/xpath
• Example 1Behavioral_Model/Process/Name
• Example 2 Behavioral_Model/Process/Name ../WCET
  12

Tree Construction
16
FLWR (FLOWER) Expression

• Flower expressions
• FOR ... LET... FOR... LET...
• WHERE...
• RETURN...

• Example find all Processes with WCET gt 14
• FOR x IN document("behavior.xml")
• //
  Process
• WHERE x/WCET gt 14
• RETURN x/_at_Id
• Result
• ltProcessgtPR6lt/Processgt
• ltProcessgtPR8lt/Processgt
• ltProcessgtPR31lt/Processgt

17
If-Then-Else

• The CC should execute within 100 ms.

ltresultsgt let a document("data/schedule.xml
")//SLOT, b max(for c in
document("data/schedule.xml")//SLOT/Start
return int(string-value(c))), d
aStart b, e aStart
b/Start, f aStart b/Duration,
g bf return ltSLOT Idd/_at_Idgt
e, f ltWCETgt
glt/WCETgt, if (ggt100) then
ltFaultgt Time Lapsed lt/Faultgt
else "WCET ok" lt/SLOTgtlt/resultsgt
18
Resource Requirement Query
for map in document("data/sweb/mapping.xml")//MAP
, nod in document("data/sweb/architecture.
xml")//NODE_at_Id map/_at_Resource let proc
document("data/sweb/behaviour.xml")//PROCESS_at_Id
map/Process return ltprocessor
Namenod/_at_Name Idnod/_at_Id
HasMemorynod/Memory/text(),nod/Memory/_at_unit
MemoryUsedByScheduledProcessessum(proc/Mem
ory),nod/Memory/_at_unitgt for process
in proc return ltprocess
Nameprocess/_at_Name
Idprocess/_at_Id
Memoryprocess/Memory/text(),process/Memory/_at_un
it /gt sortby(int(substring-before(_at_Memory,
"K"))) lt/processorgt sortby(int(substrin
g-after(_at_Id,"P")))
19
Resource Requirements Result
query resultcheck_resource_consistency.xml lt?xml
version"1.0" ?gt ltquipresult xmlnsquip"http//
.."gt ltprocessor Name"CEM" Id"P1"
HasMemory"128KB" MemoryUsedByScheduledProcesses"
20KB"gt ltprocess Name"PR1" Id"PR1"
Memory"1KB" /gt ltprocess Name"PR31"
Id"PR31" Memory"4KB" /gt ltprocess
Name"PR30" Id"PR30" Memory"5KB" /gt
ltprocess Name"PR2" Id"PR2" Memory"10KB" /gt
lt/processorgt ltprocessor Name"ABS" Id"P2"
HasMemory"256KB" MemoryUsedByScheduledProcesses"
25KB"gt ltprocess Name"PR32" Id"PR32"
Memory"1KB" /gt ltprocess Name"PR27"
Id"PR27" Memory"2KB" /gt ltprocess
Name"PR3" Id"PR3" Memory"2KB" /gt
ltprocess Name"PR4" Id"PR4" Memory"5KB" /gt
ltprocess Name"PR29" Id"PR29" Memory"7KB" /gt
ltprocess Name"PR28" Id"PR28" Memory"8KB"
/gt lt/processorgt lt/quipresultgt  
20
XQuery Software

• QuiP
• http//www.softwareag.com/developer/downloads/def
  ault.htm
• Software AG
• Windows and Linux on x86
• Features
• Latest W3C syntax
• Graphical user interface.
• Kweelt
• http//kweelt.sourceforge.net/
• Open Source
• Runs on all Java platforms
• Problems
• Older syntax, from previous W3C requirements.
• No graphical user interface.

21
xLinkit

• Xlinkit is a lightweight application service
  which provides rule-based link generation and
  checks the consistency of distributed documents
  and web content.
• xLinkit is specially designed to validate complex
  documents
• Semantics first order logic

22
Query Construction
ltDocumentSet nameCruiseCtrl"gt ltDocFile
hrefschedule.xml"/gt ltDocFile
hrefbehavior.xml"/gt lt/DocumentSetgt
ltRuleSet name"ScheduleRule"gt ltRuleFile
hrefrule4.xml xpath"/consistencyruleset/
consistencyrule"/gtlt/RuleSetgt
ltconsistencyrulesetgt ltglobalset id"schedule"
xpath"/SCHEDULE/SLOT" /gt ltglobalset
id"process_behaviour" xpath"/BEHAVIOURAL_MODEL/P
ROCESS" /gt ltglobalset id"arc_behaviour"
xpath"/BEHAVIOURAL_MODEL/ARC" /gt
ltconsistencyrule id"r1"gt ltforall var"a"
in"schedule"gt ltorgt
ltexists var"p" in"process_behaviour"gt
ltandgtltequal op1"a/_at_Id" op2"p/_at_Id"
/gt ltequal op1"a/Duration/text
()" op2"p/WCET/text()" /gtlt/andgt
lt/existsgt ltexists var"c"
in"arc_behaviour"gt
ltandgtltequal op1"a/_at_Id" op2"c/_at_Id" /gt
ltequal op1"a/Duration/text()"
op2"c/Delay/text()" /gtlt/andgt
lt/existsgt lt/orgt lt/forallgt
lt/consistencyrulegtlt/consistencyrulesetgt
23
Xlinkit Results

• ltxlinkitConsistencyLink ruleid"http//www.ida.li
  u.se/rule.xml/ consistencyruleset/consistencyrule
  1"gt
• ltxlinkitStategtconsistentlt/xlinkitStategt
• ltxlinkitLocator xlinkhref"http//www.ida.l
  iu.se/Schedule.xml/SLOT1"/gt
• ltxlinkitLocator xlinkhref"http//www.ida.l
  iu.se/Behavior.xml/PROCESS3"/gt
• lt/xlinkitConsistencyLinkgt
• ltxlinkitConsistencyLink ruleid"http//www.ida.li
  u.se/rule.xml/
• consistencyruleset/consistencyrule1"gt
• ltxlinkitStategtinconsistentlt/xlinkitStategt
• ltxlinkitLocator xlinkhref"http//www.ida.li
  u.se/Schedule.xml/SLOT3"/gt
• ltxlinkitLocator xlinkhref"http//www.ida.li
  u.se/Behavior.xml/PROCESS15"/gt
• lt/xlinkitConsistencyLinkgt

24
Discussion

• XML technologies
• Current technologies
• Xlinkit first order logic path expressions
• XQuery relational databases path expressions
• CommonRules logic programming
• Semantic Web
• DAMLOIL
• RuleML

25
Conclusions and Future Work

• Simple architecture ADL with an XML
  representation
• Modelled the cruise controller using this ADL
• Automotive electronic requirements
• Modelling and representation of requirements
  using XML technologies
• Xlinkit, XQuery, CommonRules
• Requirements on the cruise controller
• Modelled using xlinkit, XQuery and CommonRules
• Future work
• What is the advantage of using the SemanticWeb
  technologies?
• DAMLOIL instead of XML for the ADL
  representation
• RuleML instead of CommonRules