evolutionary algorithms and their applications in civil engineering - 1
TRANSCRIPT
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B Y
V A M S I D H A R T A N K A L A
&
S H R E Y M O D I
D E P A R T M E N T O F C I V I L E N G I N E E R I N G
Evolutionary Algorithms and Civil Engineering
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Consider the following problem
2 2 2 2
1 2 3 4 1 2 3 4( , , , )f x x x x x x x x
Minimize the function :
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Various methods
Mathematical differentiation , and other plotting techniques.
A computer program based on these techniques can be easily formulated.
What are the issues to be considered ?
- Computational time
- Complexity of the problem – Increase the parameters and observe the computational time
- Smoothness of the function , if not rugged techniques work efficiently
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Need for Evolutionary Techniques
Vagaries faced by the traditional techniques
Rugged landscape of the problem
Presence of many discontinuities
Simulation of the real world applications where mathematical formulations are not available :
“BLACK-BOX APPROACHES”
One example : Dynamic traffic simulation.
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Need for evolutionary procedures
“Genetic Algorithms are good at taking
large, potentially huge search spaces and
navigating them, looking for optimal
combinations of things, solutions you
might not otherwise find in a lifetime.”
- Salvatore Mangano
Computer Design, May 1995
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Brief introduction to GA’s
Directed search algorithms based on the mechanics of biological evolution
Developed by John Holland, University of Michigan (1970’s)
To understand the adaptive processes of natural systems To design artificial systems software that retains the robustness of
natural systems
Provide efficient, effective techniques for optimization and machine learning applications
Widely-used today in business, scientific and engineering circles
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Genetic Algorithm
Outline of the steps involved in GA Encoding
Initialization
Reproduction
Selection
Termination Criteria
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Deb’s example
Consider a simple can design problem
A cylindrical can considered to have only twoparameters – the diameter d and height h.
Considering that the can needs to have a volume ofatleast 300 ml and the objective of the design is tominimize the cost of the can material
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Objective function
2
2
1
min max
min max
( , ) ( )2
( , ) 300,4
df d h c dh
d hg d h
d d d
h h h
Minimize
Subject to
Variable bounds
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Representing a solution
(d,h)=(8,10) cm
(chromosome) = 01000 01010h
d
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Fitness Calculation
2( ) 0.065[ (8) (8)(10)]
23.
F s
Fitness – assigning a “goodness” measure
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A Sample random generation
23 30 11
2437
9
Cost -30
Cost-40
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Selection Operator
Identify good(usually above-average) solutions in apopulation.
Make multiple copies of good solutions.
Eliminate bad solutions from the population so thatmultiple copies of good solutions can be placed inthe population.
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Common Selection methods
Tournament Selection
Proportionate selection
Ranking selection
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Tournament selection
Mating Pool23
30
11+30
24
37
9+40
24
37
11+30
23
9+40
30
23
24
37
24
23
30
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Other Selection Operators
Ranking Selection
Stochastic Remainder roulette wheel selection
Proportionate selection
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What happens in mating pool??
Crossover Operation
Mutation Operation
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Crossover operator
(8,10) 01000 01010 01010 00110 (10,6)
(14,6) 01110 00110 01100 01010 (12,10)
23
37
22
39
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Mutation Operator
(10,6) 01010 00110 01000 00110 (8,6)22 16
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Overall understanding of GA‟s
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How to encode a solution of the problem into chromosome ?
Types of Encoding Binary coding
Difficult to apply directly
Not a natural coding
Real number coding
Mainly for constrained optimization problems
Integer coding
For combinatorial optimization problems
Ex. Quadratic Assignment Problems
Step 1: Encoding Problem
1 0 0 1 1 1 0 1
2.3352 5.3252 6.2895 4.1525
3 5 1 2 4 8 7 6
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Step 1: Encoding Problem (Cont.)
Coding Space and Solution Space
Coding SpaceGenetic Operations Solution Space
Evaluation and Selection
Encoding
Decoding
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Step 1: Encoding Problem (Cont.)
• Critical issues with encoding
Feasibility of a chromosome
solution decoded from a chromosome lies in a feasible region of the
problem
Legality of a chromosome
chromosomes represents a solution to a problem
Uniqueness of mapping (Between Chromosomes and solution to the problem)
1 - n mapping (Undesired mapping)
n – 1 mapping (Undesired mapping)
1 – 1 mapping (Desired mapping)
One chromosome represents only one
solution to the problem
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Step 1: Encoding Problem (Cont.)
Coding SpaceSolution Space
infeasible one
Coding Space
Solution Space
Feasible space
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Step 2: Initialization
Create initial population of solutions
Randomly
Local search
Feasible Solutions
For optimization problem
Minimize: F (x1, x2, x3)
Binary encoding
1 0 1 1 0 0 1 1 1 0 0 1
x1 x2 x3
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Step 2: Initialization (Cont.)
Population of solutions
Fitness of solutions are evaluated (= objective function)
1 0 1 0 0 1 0 1 1 0 1 0
0 1 1 0 1 0 1 0 0 1 0 1
0 0 1 0 1 0 1 1 1 1 0 0
0 1 0 1 0 0 1 0 0 0 1 1
1 0 0 0 1 0 1 0 1 0 0 1
1 0 1 1 1 1 0 0 0 0 1 1
0 0 1 0 1 0 1 1 0 1 1 0
0 1 1 1 1 0 0 1 1 1 0 1
0 1 0 1 0 1 0 1 1 0 0 1
1 0 0 0 1 1 1 1 1 1 0 0
Solution No.1
2
3
4
5
6
7
8
9
10
13.2783
20.3749
19.8302
52.9405
25.8202
36.0282
70.9202
38.9022
29.0292
21.9292
Fitness values
Ch
rom
oso
mes
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Step 3: Reproduction
Crossover operation (Based on crossover probability)
Select parents from population based on crossover probability
Randomly select two points between strings to perform crossover operation
Perform crossover operations on selected strings
Known for Local search operation
Crossover Points
Parent 1
Parent 2
Offspring 1
Offspring 2
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Step 3: Reproduction (Cont.)
For the example of optimization problem
Let the crossover probability be 0.8
1 0 1 0 0 1 0 1 1 0 1 0
0 1 1 0 1 0 1 0 0 1 0 1
0 0 1 0 1 0 1 1 1 1 0 0
0 1 0 1 0 0 1 0 0 0 1 1
1 0 0 0 1 0 1 0 1 0 0 1
1 0 1 1 1 1 0 0 0 0 1 1
0 0 1 0 1 0 1 1 0 1 1 0
0 1 1 1 1 0 0 1 1 1 0 1
0 1 0 1 0 1 0 1 1 0 0 1
1 0 0 0 1 1 1 1 1 1 0 0
0.9502
0.2191
0.4607
0.6081
0.8128
0.9256
0.7779
0.4596
0.9817
0.7784
Random values [0,1]Chromosomes
SolutionNo.
1
2
3
4
5
6
7
8
9
10
Solution Selected
For crossover
operationNO
YES
YES
YES
NO
NO
YES
YES
NO
YES
> 0.8
< 0.8
< 0.8
< 0.8
> 0.8
> 0.8
< 0.8
< 0.8
> 0.8
< 0.8
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Step 3: Reproduction (Cont.)
0 1 1 0 1 0 1 0 0 1 0 1
0 0 1 0 1 0 1 1 1 1 0 0
0 1 0 1 0 0 1 0 0 0 1 1
0 0 1 0 1 0 1 1 0 1 1 0
0 1 1 1 1 0 0 1 1 1 0 1
1 0 0 0 1 1 1 1 1 1 0 0
SolutionSelected
2
3
4
7
8
10
0 1 1 0 1 0 1 1 0 1 0 1
0 0 1 0 1 0 1 0 1 1 0 0
0 1 0 1 0 0 1 1 0 1 1 1
0 0 1 0 1 0 1 0 0 0 1 0
0 1 0 0 1 0 0 1 1 1 0 1
1 0 1 1 1 1 1 1 1 1 0 0
Parents Selected Offspring
Crossover Points
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Step 3: Reproduction (Cont.)
Mutation operation (based on mutation probability pm)
each bit of every individual is modified with probability pm
main operator for global search (looking at new areas of the search space)
pm usually small {0.001,…,0.01} rule of thumb pm = 1/no. of bits in chromosome
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Step 3: Reproduction (Cont.)
For optimization problemMinimize: F (x1, x2, x3)
Let pm = 1/12 = 0.083
Generate Random number [0,1] for each bit
Select bits having probability less than pm
Interchange the bits with each other
0 0 1 0 1 0 1 1 0 1 0 0
0.12 0.57 0.62 0.31 0. 01 0.73 0.83 0.63 0.02 0.26 0.94 0.63
ith solution string from the population
0 0 1 0 1 0 1 1 0 1 0 0
Mutation
1 0
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Step 4: Selection (“Survival of the fittest”)
Directs the search towards promising regions in the search space
Basic issues involved in selection phase: Sampling space:
Parents and Offspring Regular sampling space:
all offspring + few parent = pop_size
Crossover operation
Mutation operation
Population(pop_size)
Offspring produced
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Step 4: Selection (“Survival of the fittest”) (Cont.)
Basic issues involved in selection phase:
Sampling space: Enlarged sampling space: All offspring + All parent
Crossover operation
Mutation operation
Population(pop_size)
Offspring produced
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Step 4: Selection (“Survival of the fittest”) (Cont.)
Sampling Mechanism: How to select chromosomes from sampling space
Basic approaches Stochastic Samplings
Roulette Wheel selection:
To determine survival probability proportional to the fitness value
randomly generate a number between [0,1] and select the individual
Selection probability for kth individual
1
_k
pop sizek
jj
fp
f
Based on pk, cumulative probability is calculated, and roulette wheel is
constructed
Zone of kth
individual
fk is the fitness value of kth individual
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Step 4: Selection (“Survival of the fittest”) (Cont.)
Deterministic Samplings:
select best pop_size individuals from the parents and offspring
No duplication of the individuals
Mixed Samplings:both random and deterministic samplings are done
Step 5: Termination Criteria
Repeating the above steps until the termination criteria is not satisfied
Termination criteria maximum number of generations
no improvement in fitness values for fixed generation
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Summary of Genetic Algorithms
Begin
{initialize population;
evaluate population;
while (TerminationCriteriaNotSatisfied)
{
select parents for reproduction;
perform Crossover and mutation;
evaluate population;
}
}
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Issues for GA Practitioners
Choosing basic implementation issues:
Encoding
Population size, Mutation rate, Crossover rate …..
Selection, Deletion policies
Types of Crossover, Mutation operators
Termination Criteria
Performance, scalability
Solution is only as good as the evaluation function (often hardest part)
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Benefits of Genetic Algorithms
Concept is easy to understand Modular, separate from application Supports multi-objective optimization Good for “noisy” environments Always an answer; answer gets better with time Inherently parallel; easily distributed Many ways to speed up and improve a GA-based
application as knowledge about problem domain is gained
Easy to exploit previous or alternate solutions Flexible building blocks for hybrid applications Substantial history and range of use
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When to Use a GA
Alternate solutions are too slow or overly complicated
Need an exploratory tool to examine new approaches
Problem is similar to one that has already been successfully solved by using a GA
Want to hybridize with an existing solution
Benefits of the GA technology meet key problem requirements
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Some GA Application Types
Domain Application Types
Control gas pipeline, pole balancing, missile evasion, pursuit
Design semiconductor layout, aircraft design, keyboard configuration,
communication networks
Scheduling manufacturing, facility scheduling, resource allocation
Robotics trajectory planning
Machine Learning designing neural networks, improving classification algorithms, classifier
systems
Signal Processing filter design
Game Playing poker, checkers, prisoner’s dilemma
Combinatorial
Optimization
set covering, travelling salesman, routing, bin packing, graph colouring
and partitioning
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Sample Applications in Civil Engineering
Transportation Engineering
Brief discussion of following areas:
- Dynamic traffic simulation.
- Aggregate blending .
- Back calculation of Pavement Layer Modulii.
Numerous applications in Structural engineering ,environmental, geotechnical and water resourcesengineering.
Research articles are available in superfluityconcerning applications of GA in civil engineering
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Ant Colony Optimization
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Inspiration
Ants are practically blind but they still manage to find their way to the food. How do they do it?
These observations inspired a new type of algorithm called ant algorithms (or ant systems).
Result of research on computational intelligence approaches to combinatorial optimization.
The algorithm is modeled after the natural behavior of ants.
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Natural behavior of ant
Ant search for their food
Nest Food
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Natural behavior of ant
An obstacle has blocked the path of ants
Nest Food
Obstacle
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Natural behavior of ant
What to do? Every ant flips a coin and choose a path
Nest Food
Obstacle
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Natural behavior of ant
Finally, after some time shorter path reinforced
Nest Food
Obstacle
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Natural Ants
Almost Blind.
Incapable of achieving complex task alone.
Rely on the phenomena of swarm intelligence for survival.
Capable of establishing shortest-route paths from their colony to feeding
sources and back.
Use stigmergic communication via pheromone trails.
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Natural Ants
Follow existing pheromone trails with high probability.
What emerges is a form of autocatalytic behavior: the more ants follow a
trail, the more attractive that trail becomes for being followed.
The probability of a path choice increases with the number of times the
same path was chosen before.
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What isStigmergy?
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Stigmergic
A term coined by French biologist Pierre-Paul Grasse, is interaction
through the environment.
Two individuals interact indirectly when one of them modifies the
environment and the other responds to the new environment at a later
time. This is stigmergy.
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Stigmergy
Ants uses stigmergy. But how?
PHEROMONES
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Pheromones
Whatis
Pheromone?
These are chemical substances dropped by
us in our path.
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Ant Colony Optimization
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Basic Requirements
Since the ant algorithms are based on shortest path finding methodology utilized by the ants in search for their food, thus their implementation requires:
The problem to be solved must either be in graphical format or could be expressed in graphical form.
Must be finite (i.e. must have a start and end).
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Ant Algorithms
Ant systems are a population based approach. In this respect it is similar to genetic algorithms.
Each ant is a simple agent with the following characteristics:
It probabilistically chooses the node to visit with certain probability.
Uses a tabu list to avoid revisit to the node.
After the completion of tour it lays pheromone trail on each visited edge.
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Is Termination Criteria met?
Flowchart of Ant algorithms
Find SolutionsUpdate
Pheromone
Probabilistically find New solutions based On pheromone values
Evaluate Solutions
Evaluate Solutions
STOP
Update Pheromone
Yes No
Initialize Ants
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Is Termination Criteria met?
Initialization
Find SolutionsUpdate
Pheromone
Probabilistically find New solutions based On pheromone values
Evaluate Solutions
Evaluate Solutions
STOP
Update Pheromone
Yes No
Initialize Ants
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Initialization
Initially ants are randomly placed on the nodes.
Each edge is initialized with small amount of
pheromones.
Each edge‟s Visibility, a heuristic value equal to
the inverse of distance between the edge, is
initialized.
Initialize Ants
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Is Termination Criteria met?
Find Solutions
Initialize Ants Find Solutions
Update Pheromone
Probabilistically find New solutions based On pheromone values
Evaluate Solutions
Evaluate Solutions
STOP
Update Pheromone
Yes No
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Find Solutions
Each ant probabilistically select the next node to visit with certain probability given by:
Find Solutions
nodes allowed
1)(
1)(
)(
j ij
ij
ij
ij
i
dt
dt
tP j
Quantity of pheromoneon edge i-j.
Distance between edge i-j
α,β constants
Identified Using Tabu List
Probability of transition from node i to j
Cycle Number
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Tabu List
It is used by the ant to avoid revisit to any node.
It stores the node to be visited by the ant.
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Pheromone Update
After each ant complete their tour, pheromone count
on each edge is updated using:
Update Pheromone
),(
)()1()1(
jiedgeusedthatColonyk k
ijijL
Qtt
Evaporation rate
Pheromone laid by each ant that uses
edge (i,j)
Quantity of pheromoneon edge i-j during cycle t+1.
Total distance traveledby ant k during its tour
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Termination
The termination criteria commonly used are:
Designated Maximum number of cycles.
Specified CPU time limit.
Maximum number of cycles between two improvements of the global best solution.
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Control Parameters
Number of ants
Pheromone Weight ()
Visibility Weight (β)
Pheromone persistence ( )
Number of cycles
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Ant Algorithms - Applications
Travelling Salesman Problem (TSP)
Facility Layout Problem - which can be shown to be a Quadratic Assignment Problem (QAP)
Vehicle Routing
Stock Cutting (at Nottingham)
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ANT COLONY APPLICATION TO
TRAVELING SALESMAN PROBLEM – AN EXAMPLE
ILLUSTRATION
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Ant Colony Algorithms and TSP
Ant Colony Optimization was initially designed for Traveling Salesman Problem.
At the start of the algorithm one ant is placed in each city.
Assuming that the TSP is being represented as a fully connected graph, each edge has an intensity of trail on it. This represents the pheromone trail laid by the ants.
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Ant Colony Algorithms and TSP
The distance to the next town, is known as the
visibility, nij, and is defined as 1/dij, where, dij, is
the distance between cities i and j.
When an ant decides which town to move to
next, it does so with a probability that is based
on the visibility for that city and the amount of
trail intensity on the connecting edge.
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Ant Colony Algorithms and TSP
At each cycle pheromone evaporation takes
place.
The evaporation rate,1- p, is a value between 0
and 1.
In order to stop ants visiting the same city in the
same tour a data structure, Tabu, is maintained.
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Results on TSP with 10 cities
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Results on TSP with 10 cities
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Results on TSP with 10 cities
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Results on TSP with 10 cities
Optimal Solution
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Variants
Best and Worst Ant System
The best ant receives reward while the worst ant is punished. If the search stucks at a local optimum, restart is employed.
Maximum and Minimum Ant System
An upper and lower bound are exposed on the pheromone levels.
Search starts using the max.
Rank Based Ant System
The ants are sorted wrt. the fitnesses of each tour they find. Their pheromone levels are adjusted accordingly
Elitist Ant System
The best tour found at each step receives an extra pheromone.
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Concluding remarks on Ant algorithms
Ant algorithms are inspired by real ant colony.
Probability of ant following certain route is a function Pheromone intensity
Visibility
Evaporation
Ant algorithms are very suitable for problems having graphical structures.
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Particle Swarm Optimization
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Inspiration
It was inspired from the swarms in nature such as birds, fish, etc.
PSO algorithm has been originally developed toimitate the motion of flock of birds.
Particle Swarm Optimization (PSO) applies conceptof social interaction for problem solving
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Particle Swarm Algorithms
It was developed in 1995 by James Kennedy and Russ Eberhart.
PSO is a robust stochastic optimization technique based on the movement and intelligence of swarms.
In PSO, a swarm of n individuals communicate either directly or indirectly with one another search directions (gradients).
It has been applied successfully to a wide variety of search and optimizationproblems
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PSO Formulation
The algorithm uses a set of particles flying over a search space to locate a global optimum.
A particle encodes a candidate solution to a problem at hand.
During an iteration of PSO, each particle updates its position according to its previous experience and the experience of its neighbors.
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Fundamentals of PSO
A particle (individual) is composed of:
Three vectors: The x-vector records the current position (location) of the particle in the
search space,
The p-vector (pbest) records the location of the best solution found so far
by the particle, and
The v-vector contains a gradient (direction) for which particle will travel in
if undisturbed
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PSO: Generic Algorithm Schema
Initialize swarm with random position (x0)
and velocity vectors (v0)
Evaluate Fitness
For Each Particle
If
fitness(xt)> fitness (gbest)
gbest=xt
If
fitness(xt)> fitness (pbest)
pbest=xt
Update velocity
Update Position
xt+1= xt+1 + vt+1
1 2
3
0 1
0 1
t t t
t
v W v c rand( , ) ( pbest x )
c rand( , ) ( gbest x )]
Next Particle
gbest = output
End
If
Terminate
true
Start
gbest= Global Best Position
pbest= Self Best Positionfalse
c1 and c2= Acceleration Coefficients
W = Inertial Weight
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Algorithm Implementation
The basic concept of PSO lies in accelerating each particle toward the best position found by it so far (pbest) and the global best position (gbest) obtained so far by any particle, with a random weighted acceleration at each time step.
This is done by simply adding the v-vector to the x-vector to get another x-vector (Xi = Xi + Vi).
Once the particle computes the new Xi it then evaluates its new location. If x-fitness is better than p-fitness, then pbest = Xi and p-fitness = x-fitness.
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Psychosocial compromise
xgbest
pbest
v
t 1 t 1 t 2 tv W v c rand(0, 1) (pbest x ) c rand(0, 1) (gbest x )]
Particle’s
Current position
Particle’s best position so
far
Global best
position attained
gbest = Global Best Position
pbest= Self Best Position
c1 and c2 = Acceleration Coefficients
W = Inertial Weight
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Initial parameters
Swarm size
Position of particles.
Velocity of particles.
Maximum number of iterations.
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Control Parameters
Swarm size
Inertial Weight W
Acceleration Coefficients c1 and c2
Number of iterations
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Inertia Weight W
A large inertia weight (w) facilitates a global search while a small inertia weight facilitates a local search.
Larger W Greater Global Search Ability
Smaller W Greater Local Search Ability
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Acceleration Coefficients
Determines the inclination of search.
C1 larger
than C2
Greater Local Search Ability
C2 larger
than C1
Greater Global Search Ability
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Comparison with Evolutionary Algorithms (EAs)
Unlike EAs, in PSO there is no selection operator.
PSO does not implement survival of the fittest strategy and all individuals are kept as members of the population throughout the course.
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PSO implementation on TSP
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Encoding Schema
Generally PSO is applied over problems involving real variables.
However, through the use of proper encoding schema it can be applied to solve hard combinatorial optimization problems like Traveling Salesman Problem, Knapsack Problem, Node Coloring, Sequencing and Scheduling.
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Encoding Schema
For TSP, each particle’s position is coded in the form of a one dimensional string whose dimensions equals the number of cities that are to be visited.
The particles are randomly initialized with rank vectors or priority numbers.
5 9 2 4 6 3
String representation for TSP with 6
cities
Priority Numbers
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Decoding
5 9 2 4 6 3Encoded
String
Smallest Priority Number
1
Least priority is assigned the first
city
DecodedString
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Decoding
5 9 N 4 6 3Encoded
String
1 2Decoded
String
Representing that it has been decoded
Smallest Priority Number
Least priority is assigned the next
city
Repeated till all cities are assigned
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Decoding
5 9 2 4 6 3Encoded
String
4 6 1 3 5 2Finally
DecodedString
After Decoding
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Solution Strategy by Particle Swarm Algorithm
Randomly initialize the particle‟s position (ranks) and velocity. Decode the particles and evaluate objective. Store the initial position in particle‟s memory. Modify velocity using cognitive and social components and update
position. Decode the particles „position and evaluate objective. If the position of particle is better than the position stored in
memory, update memory. Update the global best if a better particle is obtained. Repeat the process till required no. of iterations are complete. The particle with best position is the output.
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Results of PSO on TSP with 10 Nodes
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Results of PSO on TSP with 10 Nodes
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Results of PSO on TSP with 10 Nodes
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Results of PSO on TSP with 10 Nodes
PSO took relatively large time to evolve
the optimal solution
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Concluding remarks on “Particle Swarm”
Fast convergence thus time requirement is less.
Global as well as Local search component.
Dependence on parameter tuning is less.
More effective on problems involving real values.
Chances of early convergence due to high convergence speed.
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ARTIFICIAL IMMUNE SYSTEM
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Artificial Immune Systems
A way to study the response of immune system,
when a non-self Antigen pattern is recognized
by Antibody
AIS are adaptive systems inspired by theoretical immunology and observed immune functions, principles and models, which are applied to complex problem domains (de Castro and Timmis)
A recently developed evolutionary technique inspired by theory of Immunology
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Biological Immune SystemEfficiency of the acquired response depends upon the ability
of antibodies to recognize the antigens, depends upon
1016 Antigens for less than 100
antibody genes
Self/Non-self Discriminatio
n
Ability to remember previous
infections
o Generalization
o Screening
o Memory
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Artificial Immune System
History of Artificial Immune System
Initially developed from the theory of “immunology”
in mid 1980’s
In 1990, first use of immune algorithm to solve
optimization problem
In mid 1990: Application to Computer Security
In mid 1990: Machine Learning
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Artificial Immune System Artificial Immune System: An Optimization View
Objective FunctionsConstraints
Feasible Solutions
Entire SolutionBuilding Blocks
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Artificial Immune Systems
Basic Elements
Immune Systems: To protect the body from the foreign matters
Antigen: Any foreign disease causing elements
Antibody: Utilized to identify, bind and eliminate antigens
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General Framework for AIS- The AIS Cycle
Selection
Evaluation
Population
Initialization
Cloning &
Hypermutation
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Artificial Immune System AIS: A Generic Framework
Application Domain
Representation
Affinity Measures
Immune Algorithm
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Flow of the Algorithm
Population P
of individuals
Clone Pool of
the population
Hypermutation
of each clone
Probabilistically select P
best individual
Repository of
good solution
When search gets stagnated good solutions are sent to
the current population
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Artificial Immune System Artificial Immune System: An Assessment
AdvantagesGeneral Purpose AIS tools
Easily Extensible
Potential for distribution
DisadvantagesParameter Sensitive
Computationally Expensive
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Artificial Immune System Distinctive Features & Their Applications:
Features Applications
Learning & Adaptation Security
Immunological Memory Pattern Recognition
Self/Non-self Classification Heuristic Optimization
Self Organizing Modeling & Agents Application
Localization & Circulation Clustering
Autonomous/Decentralized Concept Learning & Recommender System
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Artificial Immune System
AIS: Potential Area of optimization Fault & Anomaly Detection
Data Mining (Machine Learning, patter recognition)
Agent Based systems
Autonomous Control
Information Security System
Scheduling
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Dynamic traffic simulation
CALIBARTION OF MESOSCOPIC TRAFFIC SIMULATION USING POPULATION BASED EVOLUTIONARY ALGORITHMS
- methodology to calibrate dynamic trafficsimulation models with real data acquired fromtraffic counts and travel time measurementsacquired from GPS devices
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Brief outlook
To use a tool called METROPOLIS
No Mathematical function involved, hence a need forsimulation arises – simulation of the real worldconditions.
A simulation of real time traffic will be processed inthe model and it gives different indicators as output.One of the indicator is the travel time along thedefined paths in a network
Initially ,tested on toy networks (network containingsmall networks)
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Computational Details
Programmed in the following way :
- A GUI platform developed in java which works like a compiler for optimization
- The main features of the compiler are :
* Any EA can be embedded
* Any problem can be optimized
ALGORITHM PROBLEMOPTIMISATION
PLATFORM
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Overall framework
RANDOMLY GENERATE
TRAFFIC VARIABLES
PLATFORM
NODE-1
NODE-2
NODE-3
NODE-4
FITNESS
CALCULATEFITNESS
RESULTS