Interactive Genetic Algorithm with Implicit
Uncertainty Evaluation for Application in
Personalized Search
Xiaoyan Sun
School of Information and
Control Engineering
China University of Mining and
Technology
Xuzhou, China
xysun78@hotmail.com
Yang
Chen
School of Information and
Control Engineering
China University of Mining and
Technology
Xuzhou, China
fedora.cy@gmail.com
Lin Bao
School of Information and
Control Engineering
China University of Mining and
Technology
Xuzhou, China
baolin_zj@163.com
Ruidong Xu
School of Electrical and Power
Engineering
China University of Mining and
Technology
Xuzhou, China
ruidongxu@163.com
Abstract—Interactive evolutionary algorithms have been used
successfully for search and optimization problems. However,
user evaluation fatigue and uncertainties greatly restrict their
application in complex optimization scenarios. Implicit
evaluation techniques can reduce user fatigue effectively, but
methods for handling evaluation uncertainties have not yet been
explored thoroughly. We study an interactive evolutionary
algorithm with uncertain preferences using an implicit
evaluation model. First, we design a Gaussian function to define
evaluation uncertainties based on interactions. Then, by
combining the evaluation uncertainties and the interactions, we
calculate the preference weights for each variable, with which a
weighted Conditional Preference Net is constructed to provide
quantitative depiction of the user’s evaluation preference. Using
the weighted Net, we estimate the fitness of an individual for the
achievement of the evolutionary process. In the iteration, the Net
is updated according to newly performed interactions to ensure
reliable tracking of the user’s preference. We apply a genetic
algorithm-based interactive evolutionary algorithm to a
personalized search for books. The proposed algorithm
accelerates search speed, alleviates user fatigue, and achieves
higher rates of satisfying solutions.
Keywords—interactive evolutionary algorithm, Conditional
Preference Nets, personalized search, uncertainty
I. INTRODUCTION
Evolutionary algorithms (EAs) are powerful tools for
optimizing complex problems that are difficult for traditional
optimization algorithms to solve [1]. For example, genetic
algorithms (GAs) and particle swarm optimization (PSO) have
proven to be powerful for engineering design problems [2, 3].
For all types of EAs, the design of the fitness function is a
key element. However, for practical problems with qualitative
objectives to be optimized, such as the design of sunglasses or
a house layout, explicitly defined fitness functions are very
difficult, and in some cases even impossible, to obtain [4]. In
such scenarios, conventional EAs face great challenges, and
the designer or the user often evaluates solutions directly
according to their interests or demands. To this end, in 1986,
Dawkins et. al. [
5] proposed a fr
amework for an interactive
evolutionary algorithm (IEA) that imbedded a user’s
evaluations into a EA process.
In interactive evolutionary algorithms (IEAs), traditional
evolutional operators used in EAs are employed according to
the fitness values assigned by a user, rather than calculated by a
mathematical function [6]. IEAs greatly expand the range of
fields in which EAs can be applied by integrating the user’s
evaluations with evolutionary operators; however, evaluation
fatigue and uncertainty on the part of IEA users can result in
fewer generations and/or smaller populations, either of which
would greatly reduce the performance of the IEAs [7].
As surveyed in literature [8], four categories of
uncertainties were considered in evolutionary computation, i.e.
noise, robustness, fitness approximation, and time-varying
fitness functions. Due to the lack of an analytical fitness
function and the dynamic of tracking the evaluation preference
reflected in interactions, uncertainties caused by a mix of the
fitness approximation and the time-varying fitness function are
mainly discussed in our study.
To improve the performance of IEAs, many strategies have
been developed aimed at reducing user fatigue and
strengthening exploration ability [9-11]. For example,
surrogate-based models constructed to approximate user
preferences are the most direct way to reduce the user’s
evaluation burden [12]. Furthermore, to deal with the
evaluation uncertainties of the user, some specific evaluation
modes were proposed by directly adopting intervals or fuzzy
numbers to evaluate the individuals [
13]. These studies,
however, all required the user to assign the fitness explicitly to
each individual during the evolutionary process, so user fatigue
or evaluation boredom was still inevitable.
This work was supported in part by the National Natural Science
Foundation of China under grant 61473298, 61473299 and the Fundamental
Research Funds for the Central Universities under grant 2012QNA58.
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