Abstract
In order to improve network intrusion detection rate, a cooperative quantum PSO and LS-SVM network intrusion detection model (CQPSO-LSSVM) was proposed in this paper. Network feature subset is encoded into quantum particle positions, intrusion detection accuracy is used as the evaluation criteria of a subset feature merits, a synergistic quantum particle swarm algorithm are used to find the optimal feature subset, LS-SVM is used to establish a network intrusion detection model, and KDD CUP 99 dataset is used to simulation test. The results show that, compared with other models, the proposed algorithm has improved detection efficiency and the detection rate of the network intrusion.
Keywords
Introduction
As networks increasingly large scale, network security is increasingly serious, invasive behavior and the type are the diversified development, it is certain practical and theoretical significance that network intrusion detection rate is improved [1, 2, 3, 4].
Network intrusion detection feature selection is crucial, how to choose the optimal feature subset is directly related to network intrusion detection results, the current network feature selection algorithm is divided into two categories: exhaustive search algorithms and swarm intelligence optimization algorithm [5, 6, 7]. Exhaustive algorithm is complexity, its time consuming is long, it can not be applied for on-line network intrusion detection requirements, in swarm intelligence optimization algorithm, particle swarm algorithm performance is excellent, but there are difficult to overcome their own shortcomings, such as it is easy to fall into local minima, etc. [8]. Classifier construction is the second step of network intrusion, it is equally important, there are neural networks currently, support vector machines, least squares support vector machine (Least Square Support Vector Machine, LS-SVM), etc. [9, 10]. Neural networks is based on the “big” quantitative,it requires a large number of samples, if the requirementscan not be meet, detection performance is very poor, there is the smaller range of applications [8]; although support vector machine has the excellent performance, but the training process is computational complexity, there is low efficiency, it can not meet the real-time network intrusion demanding areas, such as military security and network security [11, 12]. LS-SVM combines the advantages of neural networks and support vector machines, training is not only fast speed, and there is strong generalization ability, LS-SVM is selected in this article to build intrusion detection classifier [13]. Cooperative Quantum-behaved Particle Swarm Optimization algorithm (CQPSO) is an improved quantum behavior of particle swarm algorithm, it is with easy implementation, robustness, etc., it has been widely used in many areas [14].
In order to improve network intrusion detection effect, a synergistic quantum particle swarm algorithm and least squares support vector machine are integrated in network intrusion detection model (CQPSO-LSSVM), and the effectiveness of CQPSO-LSSVM is tested in the simulation experiment.
CQPSO-LSSVM intrusion detection process.
CQPSO-LSSVM intrusion detection principle
CQPSO-LSSVM basic idea is as follows: network data is collected and pretreatmented, and then CQPSO algorithm is used to select a feature subset, LSSVM is adopted to establish intrusion detection classifier. CQPSO-LSSVM frame is shown in Fig. 1.
Cooperative quantum-behavior particle swarm algorithm
Quantum-behavior particle swarm algorithm
Let the number of individuals be
Where,
To improve the performance of PSO, Kennedy proposed a quantum particle swarm optimization (QPSO) [15], conditions is Eq. (2) for its application:
In the formula,
Quantum particles have a space flight behavior, but it does not have the velocity vector,
Where,
Monte Carlo Simulation is used to update particle position:
Where,
mbest is calculated as follows:
Distance between
Where,
The relevant variables are replaced into the Eq. (5), the update formula particles may be further expressed as Eq. (9):
Coevolution idea is that the entire population is divided into a plurality of sub-groups within the solution space, the search strategy of only one population is changed, it can effectively reduce the population puberty problems wich is caused due to late iteration diversity decline. In this paper, through the creation of population gene pool, particles share information among subgroups [16].
Learning behavior of particles
In order to increase the particle swarm search capabilities and to learn from other particles in the evolution, the following improvements are made to the Eq. (2):
Where, lrand is the value of (0, 1) random numbers,
To make the particles reach equilibrium state between themselves development and population search capability,
Where,
The above-described QPSO algorithm with cooperative search strategy and learning behavior is defined as cooperative quantum particle swarm algorithm (CQPSO).
Network status information is gatherd, and its appropriate treatment is made to obtain the status vector of network feature. Current position The whole quantum particle swarm is divided into Shrinkage expansion coefficient The adapted value of the particle is updated, subgroup If the evolutionary cycle is reached, population gene pool is updated, according to Returns to the Step 4, repeat the above steps until the completion of iteration. The The network intrusion optimal feature subset is used to build intrusion detection model.
Algorithm performance testing
To test the performance of CQPSO algorithm, three standard functions of Benchmark are selected to test its performance, they are defined as follows:
Rosenbrock function
Performance comparison between CQPSO algorithm and QPSO algorithm.
The global optimum unimodal function value is 0, the optimal solution is for
The best global multimodal function value is 0, the optimal solution is for
The best global multimodal function value is 0, the optimal solution is for
QPSO comparative tests areexperimented, parameters are selected: Particle Swarm is 20, subgroup size is 5,
KDD CUP 99 characteristics
Sample data in simulation
KDD CUP 99 dataset is used as a simulation object [17, 18, 19]. Each record includes a feature 41, which are as shown in Table 1. Sample data of simulation experiments are shown in Table 2.
Comparison model and evaluation criteria
To make the test results CPSO-LS SVM more convincing, fusion models (QPSO-LSSVM) between Quantum Particle Swarm Optimization and Least Squares SVM is selected, comparative tests are done between PSO and LS-SVM fusion model (PSO-LSSVM), and four aspects of their performance are tested in the false positive rate, false negative rate, detection rate and speed [20].
Since network intrusion characteristics are more, there is large range, in order to obtain better intrusion detection effect, characteristic values are pretreatmented in particular:
In Eq. (15),
Detection rate comparison between different models of network intrusion.
False negative rate comparison between different models of network intrusion.
False alarm rate comparison between different models of network intrusion.
Running speed comparison between different models of network intrusion.
Detection rate, false negative rate, false positive rate of of various models are shown in Figs 3–5. The following conclusions can be obtained from Figs 3–5:
With respect to the PSO-LSSVM network intrusion detection model, network intrusion detection effect of QPSOLSVM has been improved, the false negative rate and false alarm rate are reduced accordingly, which indicates that the quantum particle swarm algorithm is better than particle swarm algorithm, better feature subset can be obtained, the effectiveness of the network intrusion detection is improved. With respect to QPSO-LSSVM, CQPSO-LSSVM network intrusion has even better results and better detection performance, it is mainly due to the synergy of quantum particle swarm, through the introduction of collaborative strategies, CQPSO-LSSVM can avoid falling into local optimal solution, the convergence rate is accelerated, network intrusion detection effect is better.
Intrusion detection time of each model are shown in Fig. 6. It can clearly be seen from Fig. 6 that CQPSO-LSSVM detection time is less than other network intrusion detection model, its detect is the fastest, CQPSO-LSSVM can better meet the requirements of network intrusion detection online.
In order to improve the speed of network intrusion detection, more desirable results are obtained in intrusion detection, a synergistic quantum PSO and LS-SVM network intrusion detection model is proposeed, the cooperative quantum particle swarm algorithm is used to select the network intrusion features, the number of characteristic is reduced in which LSSVM enter, the computational complexity is reduced, the simulation results show that CQPSO-LSSVM has improved intrusion detection rate, it can satisfy the requirements of online intrusion detection, CQPSO-LSSVM has broad application prospects in network security field.
Footnotes
Acknowledgments
This work is sponsored by the Scientific Research Project (NO. 14A084) of Hunan Provincial Education Department, China.
