What is BISON doing? Let us try to be precise - Geoff Canright Telenor R&D Norway
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What is BISON doing?
Let us try to be precise…
Geoff Canright
Telenor R&D
Norway
Project funded by the Future and Emerging Technologies arm of the IST ProgrammeWhat is BISON about? We want to implement a number of functions on a variety of network structures, using complex adaptive systems (CAS) which have nice properties Functions, structures, CAS: we have some progress towards precision in definitions Nice properties (adaptive, robust, etc): to be rendered more precise in 1st half 2004 1st Review Meeting 23 February 2004 2
Structures
Our original list: P2P, Grid, Virtual, Ad-Hoc
Improved: Overlay (logical) networks (OL) vs. mobile
(wireless) ad-hoc networks (MANETs)
More precise: structure = topology
• We have a growing list: lattice, random, scale-free, small-
worlds, etc.
• Some arise spontaneously; others must be managed (more
on this soon)
• In the OL case, routing and connectivity are cheap and
easy Î many possible topologies
• An (unmanaged) MANET has a (dynamic) “spatial
topology”
1st Review Meeting 23 February 2004 3Functions
Basic functions: routing, search, monitoring,
aggregation, topology management
Advanced functions: distributed content,
distributed storage, distributed processing
The basic/advanced distinction is not so precise
We can write all basic functions (except topology
management) as flow diagrams
We use load balancing in two of our advanced
functions, but haven’t placed it in our scheme
1st Review Meeting 23 February 2004 4Some flow diagrams for
basic functions
goodness routing
( S , D) + ⇒ ⇒ ( path(s))
criteria function
resource search locations ,
⇒ ⇒
specificat ion function resources
raw monitoring health
⇒ ⇒
data function indices
1st Review Meeting 23 February 2004 5Advanced functions
Distributed processing: work to be done is
shared — try to use capacity of all participating
nodes (load balancing)
Distributed storage: a distributed warehouse.
Can I fetch my files when I want them? (load
balancing; also, need redundancy/reliability)
Content sharing: a distributed library. No
ownership of content. How to find stuff?
1st Review Meeting 23 February 2004 6The significance of topology
management
Some topologies support a given function better (even
much better!) than others
At least in the OL case, we can aim for techniques for
maintaining a desired topology to support a desired
function
Close the loop: we use (other) functions to support the
target topology
Î “layered” approach (see Bologna talk):
given topology supports functions, which support new
topologies, and so on
MANETs: we do not rule out interesting possibilities
here either
1st Review Meeting 23 February 2004 7CAS = COW (can of worms)
Need to avoid ambiguous and confusing
language
We have a “BISON working definition”:
• many simple agents
• sensitive to their environment
• interacting via local roles
• the interaction is not “brute parallel”
NB1: we view our agents as finite-state machines
(FSMs); this gives an implicit definition of “simple”
NB2: brute parallelism fits easily in our scheme,
but we don’t wish to call it a CAS
1st Review Meeting 23 February 2004 8Building blocks for agent behavior
Agents are FSMs, augmented with other things. They
have types (state structures) A,B,C,… and states
a,b,c,…
We call our building blocks microscopic mechanisms:
1. Aa Î Aa (survival, memory)
2. Aa Î 0 (death)
3. A Î AA (proliferation)
4. Aa Î Ab (response, interaction)
5. A Î AB (signaling)
6. A Î A (mobility)
7. A ÎB (mutation)
1st Review Meeting 23 February 2004 9The biological inspiration
We have looked at (to date) five biological
systems with interesting behavior:
• Ants: path finding using pheromone; gathering
• Immune cells: search, recognition, and response
to antigens
• Slime mold amoebae: physical aggregation as a
response to collective hunger, using chemotaxis
• Neurons: collective memory using synapse
modification
• Viruses: epidemic spreading
1st Review Meeting 23 February 2004 10Analysis of the 5 biological systems
using our basic building blocks
Immune
Ants Amoebae Neurons Viruses
cells
Memory
(state) x x x x
Selection x x
Proliferation x x
Response x x x x
Signaling
(diffusive) (x) x
Signaling
(nondiffusive) x x
Mobility x x x x
Mutation x (x)
1st Review Meeting 23 February 2004 11What BISON is about (II)
“Engineering with emergence”
set of
abstract collective
microscopic ≡ emergence
→ = ( function )
mechanisms CAS behavior
Collective behavior is easy to predict when the
interaction is trivial
We also want to predict collective behavior for
nontrivial interactions, which exhibit emergence
1st Review Meeting 23 February 2004 12A BISON goal:
systematic understanding
This is hard!
That is: at the end of BISON, we can seek to
extract some systematic understanding from
our experience
We envision using two approaches:
Collection of performance results—focus on
effects of topology, and of CAS/mechanism
Collection of heuristics for “design” of CAS to
perform a given function
1st Review Meeting 23 February 2004 13One type of heuristic
for CAS design: “synthesis”
Look at known examples—analyze them in
terms of our microscopic mechanisms—and
compare them
Generate new candidate CAS by “tweaking”
the known sets of microscopic mechanisms
EX: slime mold colonies perform collective
computation of the colony’s level of hunger;
and they move (physically aggregate) as part
of the process
Candidate: the same set of mechanisms can
perform collective computation, but without
mobility
1st Review Meeting 23 February 2004 14Another heuristic: “operators”
An “operator” takes (CAS) ⇒ (CAS)’
• That is, it creates a new CAS from a given one
• EX1: “inversion”. Given a CAS with known collective
behavior, invert one or more microscopic mechanisms
to get inverted collective behavior
• Ants: inverted gathering = load balancing
• Chemotaxis: inverted aggregation = load balancing
• EX2: “exaptation”. Put a CAS in a new environment,
and it can display enhanced functioning
• Immune system: RW + proliferation appear to give
efficient search on a network
• How far can one go with this approach??
1st Review Meeting 23 February 2004 15You can also read
