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Fireworks algorithm is a newly risen and developing swarm intelligence algorithm, the performance of which is determined by the tradeoff between exploration and exploitation. How to develop a satisfactory weight for exploration and exploitation is an interesting and challenging work. In this paper, the landscapes of optimization problem are firstly analyzed, and then a new sparks explosion strategy is designed to represent and mine the landscape information. Moreover, the exploration and exploit
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An Improved Fireworks Algorithm with Landscape
Information for Balancing Exploration and
Exploitation
Junfeng Chen
∗†
, Qiwen Yang
∗†
, Jianjun Ni
∗†
, Yingjuan Xie
∗†
, Shi Cheng
‡
∗
College of IOT Engineering, Hohai University, Changzhou China
†
Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology, Changzhou China
‡
Division of Computer Science, University of Nottingham Ningbo, China
Email: chen-1997@163.com, qwyang2k@126.com, shi.cheng@nottingham.edu.cn
Abstract—Fireworks algorithm is a newly risen and devel-
oping swarm intelligence algorithm, the performance of which
is determined by the tradeoff between exploration and ex-
ploitation. How to develop a satisfactory weight for exploration
and exploitation is an interesting and challenging work. In
this paper, the landscapes of optimization problem are firstly
analyzed, and then a new sparks explosion strategy is designed
to represent and mine the landscape information. Moreover, the
exploration and exploitation coexist in the improved fireworks
algorithm, which can automatically adjust the search strategies
according to landscape structure. Finally, numerical experiments
are performed for the algorithms investigations, performance
analysis, and comparisons. The simulation results indicate that
the proposed algorithm has a significant performance on all the
test functions and can achieve the global minimum for most test
functions.
Index Terms—Fireworks algorithm, landscape information,
exploration, exploitation
I. INTRODUCTION
Fireworks Algorithm (FWA) [1], [2] is a newly risen and
developing swarm intelligence algorithm, which is inspired by
the explosion and illumination of fireworks in the night sky.
It is originally attributed to Tan and Zhu, and was modified
for solving practical problems, such as nonnegative matrix
factorization [3], digital filters [4], spam detection [5], and
oil crop fertilization [6]. Similar to most swarm algorithms,
FWA makes few or no assumptions about the problem being
optimized and takes an advantage of swarm searching with
a population (called a swarm) of candidate solutions (called
sparks) to seek high quality solutions of complicated optimiza-
tion problems efficiently and effectively.
Many researchers believe that the behavior of a swarm algo-
rithm is determined by two forces: exploration and exploitation
[7]. Excessive exploitation will be high-efficiency, but easy
to induce premature convergence. Excessive exploration will
increase accuracy, but consume too much computation time.
Thus, how to get a tradeoff between the exploration and
exploitation is really a key to the global performance of
swarm intelligence algorithms. Many strategies for balancing
exploration and exploitation were proposed in the past decade.
For instance, Blum and Roli pointed out that the mechanisms
of metaheuristics to efficiently explore a search space are all
based on intensification and diversification, although they are
inspired by different philosophies [7]. Liu et al. introduced an
entropy-driven exploration and exploitation approach for evo-
lutionary algorithms [8]. Olorunda and Engelbrecht developed
a diversity rate for a particle swarm optimization to quantify
the rate of change from exploration to exploitation [9]. Zhao et
al. designed fitness function, crossover operator and mutation
operator for the genetic algorithms to improve the explorative
capabilities and the exploitation effects [10]. Epitropakis et al.
proposed a hybrid differential mutation method, which was a
linear combination of the explorative and exploitive operators
[11]. Lin and Gen introduced fuzzy logic control into genetic
algorithm for balancing between exploration and exploitation
[12]. Li et al. presented a well-designed density estimator for a
dynamic neighborhood evolutionary algorithm, which achieves
auto-tuning between proximity and diversity [13]. Pei et al.
employed elite individuals sampling, the elite neighborhood
sampling and random sampling strategies into the FWA for
approximating fitness landscape and enhancing search capa-
bility [14]. Liu et al. provided a new parameter for FWA
to control the exploration and exploitation dynamically [15].
Crepinsek et al. discussed what components of evolutionary
algorithms contribute to exploration and exploitation, when
exploration and exploitation are controlled and how balance
between exploration and exploitation is achieved [16].
In view of the above-mentioned facts, FWA is not sophis-
ticated enough and can be further improved by developing a
satisfactory weight for exploration and exploitation. Moreover,
the same search strategies may result in different optimization
effects, when dealing with simple and smooth landscapes,
or dealing with bumpy and rough landscapes. In our view,
the search efficiency of FWA is not only influenced by
search strategies, but also related to the fitness landscape of
optimization problems to be solved. As a result, the main
objective of this paper is to reveal the relationship between
the landscape information of optimization problems and the
interaction mechanisms of exploration and exploitation of
FWA.
The remaining paper is organized as follows. In Section
978-1-4799-7492-4/15/$31.00
c
2015 IEEE
1272
II, the basic optimization process of FWA is reviewed. In
Section III, an improved FWA for auto-tuning exploration
and exploitation is proposed and the balance mechanism
is analyzed, followed by experimental simulation and result
discussion on benchmark functions in Section IV. Finally, our
concluding remarks are contained in Section V.
II. C
ANONICAL FIREWORKS ALGORITHM
For simplicity, we focus on an unconstrained minimization
problem in bounded space with finite dimensions in the form
of
∀
x ∈𝒮:min𝑓(
x) (1)
where
x designates a position or candidate solution in the
search-space, 𝒮 is a finite dimensional search space, and 𝑓(
x)
is the fitness or cost function to be minimized.
The canonical FWA works on a new search mechanism
which describes the evolution of a population of sparks
in the search space for problem solving. A set of sparks
X =[
x
1
,
x
2
, ⋅⋅⋅ ,
x
𝑁
] composed by 𝑁 sparks with encoding
length 𝑀, can be written in the following vector and matrix
forms:
X =
⎡
⎢
⎢
⎢
⎣
x
1
x
2
.
.
.
x
𝑁
⎤
⎥
⎥
⎥
⎦
=
⎡
⎢
⎢
⎢
⎣
𝑥
11
𝑥
12
⋅⋅⋅ 𝑥
1𝑀
𝑥
21
𝑥
22
⋅⋅⋅ 𝑥
2𝑀
.
.
.
.
.
.
.
.
.
.
.
.
𝑥
𝑁1
𝑥
𝑁2
⋅⋅⋅ 𝑥
𝑁𝑀
⎤
⎥
⎥
⎥
⎦
=
⎡
⎢
⎢
⎢
⎣
g
1
g
2
.
.
.
g
𝑀
⎤
⎥
⎥
⎥
⎦
𝑇
(2)
where
x
𝑖
=[𝑥
𝑖1
,𝑥
𝑖2
, ⋅⋅⋅ ,𝑥
𝑖𝑀
] ∈𝒮is the 𝑖-th sparks in X,
and 𝑥
𝑖𝑗
is the 𝑗-th solution component of the 𝑖-th sparks, 𝑖 =
1, 2, ⋅⋅⋅ ,𝑁, 𝑗 =1, 2, ⋅⋅⋅ ,𝑀. For the sake of convenience,
the 𝑗-th vector which consists of the 𝑗-th components of all
the sparks in X is called the 𝑗-th set component, written as
g
𝑗
=[𝑥
1𝑗
,𝑥
2𝑗
, ⋅⋅⋅ ,𝑥
𝑁𝑗
]
𝑇
.
Generally speaking, FWA has three main operators: calcu-
lating, creating and mapping. More specifically, calculating
operator consists of computing explosion number and ampli-
tude, creating operator refers to generating explosion sparks
and Gaussian sparks, and mapping operator means bounding
sparks back to search space. A principle FWA is described as
Algorithm 1.
The number of sparks generated by a firework
x
𝑖
is defined
as follow.
𝐻
𝑖
= 𝐾 ⋅
𝑓(
ˇ
x) − 𝑓 (
x
𝑖
)
∑
𝑁
𝑗=1
(𝑓(
ˇ
x) − 𝑓 (
x
𝑗
))
(3)
where 𝐾 is a parameter controlling the number of explo-
sion sparks.
x
𝑖
is the 𝑖-th sparks,
ˇ
x is the worst fireworks
with the maximum fitness value, i.e., 𝑓 (
ˇ
x) = max(𝑓 (
x
𝑖
)),
𝑖 =1, 2, ⋅⋅⋅ ,𝑁.
To avoid overwhelming effects of splendid fireworks,
bounds are defined for 𝐻
𝑖
.
𝐻
𝑖
=
⎧
⎨
⎩
𝐻
min
if 𝐻
𝑖
<𝐻
min
𝐻
max
if 𝐻
𝑖
>𝐻
max
𝐻
𝑖
otherwise
(4)
where 𝐻
min
and 𝐻
max
are the lower and upper bounds of
sparks numbers.
Amplitude of explosion for each firework is defined as
follows
𝐴
𝑖
= 𝑅 ⋅
𝑓(
x
𝑖
) − 𝑓 (
ˆ
x)
∑
𝑁
𝑖=1
(𝑓(
x
𝑖
) − 𝑓 (
ˆ
x))
(5)
where 𝑅 denotes the maximum explosion amplitude and
ˆ
x is
the best fireworks with the minimum fitness value, i.e., 𝑓(
ˆ
x)=
min(𝑓(
x
𝑖
)), 𝑖 =1, 2, ⋅⋅⋅ ,𝑁.
The basic FWA contains a rough thinking of the tradeoff
between exploration and exploitation. The exploitation implies
the fireworks with better fitness generate a larger population
of explosion sparks within a smaller range. While exploration
means the fireworks with lower fitness can only generate a
smaller population with higher explosion amplitude.
III. I
MPROVED FWA WITH LANDSCAPE INFORMATION
A. Landscape Information of Optimization Problems
No free lunch theorem [17] indicates that no search strategy
can keep optimal when optimizing arbitrary problems. In other
words, a general-purpose and universal optimization algorithm
is impossible. The only way that one strategy can outperform
another is if it is specialized to the structure of the specific
problem under consideration. However, we know nothing
about the landscape structure when dealing with a black-box
problem. As a result, How to get and sustain the domain
knowledge of specific optimization problems is a fundamental
issue in the swarm intelligence field.
In this paper, we try to design a new sparks explosions
strategy which is characterized of representing and mining
the landscape information of optimization problem. Specifi-
cally, the landscape of optimization problem is approximately
described as the distribution structure of candidate solutions
during the searching process of FWA.
Here, we take a simple mathematical function 𝑓(𝑥, 𝑦)=
sin(𝑥) ⋅ sin(𝑦) to illustrate the basic idea of the proposed
method. When 𝑥, 𝑦 ∈ [0, 2𝜋], the landscape structure is shown
as Fig. 1.
From Fig. 1 (a), the three-dimensional surface image has
two maxima and two minima, and its corresponding contours
describe the curves with the same function values. The color
is deeper and cooler and the value is smaller. Fig. 1 (b) is
the contour chart with the accumulated candidate solutions
of FWA iterating. The black dots represent the candidate
solutions, plotted by the variable x on the horizontal axis and
the variable y on the vertical axis. In general, a swarm intel-
ligence algorithm only makes full use of evaluation function
rather than other additional information. In other words, swarm
algorithms only consider about whether a candidate solution is
superior to another or not, regardless of distribution differences
of the candidate solutions. However, there is much useful
information in the function landscape. For example, Fig. 1 (c)
represents the distribution structure of candidate solutions with
small evaluation values. It can be seen that these candidate
solutions outline the local landscapes of minima, which are
located on the lower-right and the upper-left parts.
In practice, there are lots of difficult optimization problems,
which landscapes are relatively complicated and diverse. Some
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