Software Engineering, Collaborative Systems, other stuff

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Software Engineering, Collaborative Systems,
other stuff

• David Stotts
• Dept. of Computer Science
• Univ. of North Carolina at Chapel Hill
• August2003

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Recent Projects

• JAX/AJAX Informal formal methods for regression
  testing
• HUnit Automated regression testing for Haskell
• Ovaltine/Ovid Hypermedia links in real-time
  video
• CobWeb Model Checking coordination protocols
• EDPs and Design Pattern discovery
• DeCo Environmental modeling and federation
• dPP/dXP Collaborative, agile software
  development
• Transparent video facetop

3
Research Projects

• Design Pattern discovery
• DeCo Federated Scientific Models
• dPP/dXP distributed Pair Programming
• Transparent Video Facetop

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Elemental Design Patterns and Design
Pattern Discovery
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Example Pattern

• Composite

Comp 204 fall
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In reality, they look like this
// Composite pattern -- Structural example using
Systemusing System.Textusing
System.Collections// "Component"abstract
class Component  // Fields  protected string
name // Constructors  public Component(
string name )  this.name name //
Methods  abstract public void Add(Component
c)  abstract public void Remove( Component c
)  abstract public void Display( int depth
)// "Composite"Class Composite
Component  // Fields  private ArrayList
children new ArrayList()  // Constructors 
public Composite( string name ) base( name )
 // Methods  public override void Add(
Component component )  children.Add( component
)   public override void Remove( Component
component )  children.Remove( component ) 
public override void Display( int depth ) 
Console.WriteLine( new String( '-', depth )
name )    // Display each of the node's
children    foreach( Component component in
children )      component.Display( depth 2
) 
// "Leaf"class Leaf Component //
Constructors  public Leaf( string name ) base(
name )   // Methods  public override void
Add( Component c )  Console.WriteLine("Cannot
add to a leaf")   public override void
Remove( Component c )  Console.WriteLine("Canno
t remove from a leaf")   public override void
Display( int depth )  Console.WriteLine( new
String( '-', depth ) name ) public class
Client  public static void Main( string args
)     // Create a tree structure    Composite
root new Composite( "root" )    root.Add( new
Leaf( "Leaf A" ))    root.Add( new Leaf( "Leaf
B" ))    Composite comp new Composite(
"Composite X" )    comp.Add( new Leaf( "Leaf
XA" ) )    comp.Add( new Leaf( "Leaf XB" )
)    root.Add( comp )    root.Add( new Leaf(
"Leaf C" ))    // Add and remove a leaf   
Leaf l new Leaf( "Leaf D" )    root.Add( l
)    root.Remove( l )    // Recursively
display nodes    root.Display( 1 ) 
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Or this
// Purpose. Composite //
Strategy. Use recursive composition
// to create a
heterogeneous aggregate include ltstring.hgt
// that can be treated
homogeneously. enum NodeType FileT, DirT
// int g_indent 0
// Benefit. No more type checking and
// type casting
(coupling between Dir class File
// and File is gone, Dir is
only public //
coupled to abstract base class) File( char n
) type_ FileT strcpy( name_, n )
class AbsFile NodeType getType()
return type_ public void ls()
virtual void ls() 0 for
(int i0 i lt g_indent i) protected
cout ltlt ' ' char
name_20 cout ltlt name_ ltlt endl
static int indent_ private
NodeType type_
int AbsFileindent_ 0 char
name_20
class File public AbsFile
public class Dir
File( char n ) public
strcpy( name_,
n ) Dir( char n ) type_ DirT
void ls() strcpy( name_, n ) total_ 0
for (int i0 i lt indent_ i)
NodeType getType() return type_
cout ltlt ' ' void add( File f )
cout ltlt name_ ltlt endl
files_total_ f void
ls() class Dir
public AbsFile for (int i0 i lt
g_indent i) public cout ltlt ' '
Dir( char n ) cout ltlt
name_ ltlt "" ltlt endl strcpy( name_, n
) total_ 0 g_indent 3
void add( AbsFile f ) for (int
i0 i lt total_ i) files_total_
f if (files_i-gtgetType()
void ls() DirT)
for (int i0 i lt indent_ i)
((Dir) files_i)-gtls() cout ltlt '
' else
cout ltlt name_ ltlt "" ltlt endl
files_i-gtls() indent_ 3
g_indent - 3 for
(int i0 i lt total_ i) private
files_i-gtls()
NodeType type_
indent_ - 3 char name_20
private File files_10
AbsFile files_10 int
total_ int
total_
void main( void ) void
main( void )
Dir one("1"), two("2"), thr("3")
Dir one("1"), two("2"), thr("3") File
a("a"), b("b"), c("c"), File a("a"),
b("b"), c("c"), d("d"), e("e")
d("d"), e("e") one.add( a )
one.add( a )
one.add( (File) two ) one.add(
two ) one.add( b )
one.add( b ) two.add( c )
two.add( c ) two.add( d )
two.add( d ) two.add(
(File) thr ) two.add( thr )
thr.add( e ) thr.add(
e ) one.ls()
one.ls()

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Or this
(defgeneric add-dependent (dm dependent
ampoptional recursivep) see below for the
optional args (documentation quotAdd
DEPENDENT as a dependent of DM. Return
DMquot)) (defgeneric delete-dependent (dm
dependent ampoptional recursivep)
(documentation quotRemove DEPENDENT from
DM. Return DMquot)) No DELETE-DEPENDENT-IF
(defgeneric map-dependents (f dm)
(documentation quotMap F over the
dependents of DM. Return DMquot)) No
cursors. (defgeneric make-collection-for-dependen
t-mixin (dm)) (defclass dependent-mixin ()
something that has dependents. We expose the
DEPENDENTS slot. ((dependents reader
dependents-of))) (defmethod make-collection-for-d
ependent-mixin ((dm dependent-mixin))
(make-instance 'simple-childed-mixin)) (defmethod
initialize-instance after ((dm dependent-mixin)
ampkey) (setf (slot-value dm
'dependents) (make-collection-for-dependent-mixin
dm))) (defmethod add-dependent ((dm
dependent-mixin) dependee ampoptional
recursivep) (declare (ignorable recursivep))
(add-child (dependents-of dm) dependee)
dm) (defmethod delete-dependent ((dm
dependent-mixin) dependee ampoptional
recursivep) (declare (ignorable recursivep))
(delete-child (dependents-of dm) dependee)
dm) (defmethod map-dependents (f (dm
dependent-mixin)) (map-over f (dependents-of
dm)) dm)
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Patterns Intertwingled

• All non-trivial designs
• involve many
• cross-mixed
• patterns

Same class might be a component in 4 or 5
patterns
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Redirect In Family
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Redirect In Family Isotope
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SPQR System
Source code
gcc
gcc2oml
gcc parse tree
object XML
oml2otter
Source-code-specific otter clauses
Found patterns report
Rho calculus compos rules
EDP catalog
python
Otter theorem prover
Otter proofs
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Extended Example
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Rho Calculus Definitions
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Found Patterns
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Object Recursion - Annotated
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Decorator Pattern
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Decorator - Annotated
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Architecture for Federated Environmental Modeling

• Atmosphere, Meterology, Hydrology, Soil
  Chemistry, Geology, Marine Biology...
• Different research communities, specialties
• Different models different mathematics
  different abstractions and domains of
  discourse... different software architectures
• Limited interactions, difficult information
  exchange

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Multi-media Modeling

• To EnviSci this means dirt AND air AND
  watersheds in one analytical context
• Currently done with manual data communications
  I ask you for some rainfall data from your
  atmosphere model I take it and make an input
  file in the format my soil model needs to
  generate runoff data for an estuary model...
• Further complications to get me some rain data,
  you may need from my soil model some evaporation
  data feedback loops

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Multi-media Modeling
Air model
Water model
soil model
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Not so fast...

• spatial scale mismatch
• time scale mismatch
• mathematical method mismatch (finite elements vs.
  pdes vs. genetic algs vs. simulated annealing,
  e.g.)
• Error tracking and bounding during execution

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Multi-media Modeling
Air model
5 minute steps
Water model
3 hour steps
soil model
1 month steps
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Multi-media Modeling
Mismatch management module
Air model
5 minute steps
Water model
3 hour steps
soil model
1 month steps
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DeCo

• Functional layer (Haskell) for gluing together
  environmental (scientific) models, handling
  mismatches in data, timing, space scale
• Current trials
• Neuse river hydro model (Alperin)
• Sedimentation model (Bowen)
• Together can answer questions like
• If we dump X tons of substance Y in the Neuse at
  New Bern in May, what concentration of Y will we
  find 6 cm deep in the mud at the river mouth 6
  months later?
• Herington MS Thesis

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New Areas

• Human lung model biochemistry, fluid dynamics,
  protein motors and cilia mechanics, cell
  physiology for cystic fibrosis research

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New Areas

• Bioinformatics
• searching genome databases with disparate set of
  tools each tool used for a partial solution, and
  one tool producing as output the data needed as
  input for another

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Project Goals

• Modular framework for scientific model
  interconnection and interoperation
• Methods of composing models
• Support for distributed model data and net-based
  model execution

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Distributed Pair Programming and
Collaborative Software Engineering
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Extreme Programming (XP)

• Lightweight development process
• Test-first development, rapid spin cycle,
  client-centered requirements
• Code Refactoring
• Pair Programming
• COMP 290 spring

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?? Distributed XP ??

• What if the programmer pairs are not co-located?
• Are productivity benefits of XP maintained?
• PCAnywhere, collaboration tools
• Joint experiments with Laurie Williams (NCSU)

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Findings

• Distance matters is a truism among
  collaborative systems researchers ( Olson
  Olson )
• Studies of graduate programmers (136, 16, 12, 2)
• Paired, non-paired, co-located, distributed

We are finding that distance doesnt always
matter doesnt matter as much as thought
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Video-Enhanced Environment

• In all studies, dPP programmers say
• we need a whiteboard
• we miss facial expressions
• we cant point at what we are sharing
• We are constructing a video-enhanced dPP
  environment to address these issues

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Environment Schematic
 
Right-hand user, can reach from seat, write on
projected digital whiteboard
Shared PC projection
projector
keyboard, etc.
Partner / whiteboard
projection
programmer
camera
projector
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Alternatives
 
Partner projection
Shared PC projection
Less useful for whiteboard , Perhaps more
effective with multi-screen unified wide display
keyboard, etc.
camera
programmer
projector
projector
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90º Projector Setup
Daily use 2 PCs switched between 2 projectors and
a monitor
dPP use Both projectors at once, one for
communication, one for shared PC desktop
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Solving the Pointing Problem
Vis-a-vid Transparent Video FaceTop
Single-user track finger, drive mouse, self-image
provides cues not found in other UIs
Collaborative put two people on one shared
screen, Each sees the other pointing
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VaV Mac Prototype Demo
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Come join us in our Lab
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End of Presentation