• Title/Summary/Keyword: Hybrid algorithms

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ACCELERATED HYBRID ALGORITHMS FOR NONEXPANSIVE MAPPINGS IN HILBERT SPACES

  • Baiya, Suparat;Ungchittrakool, Kasamsuk
    • Nonlinear Functional Analysis and Applications
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    • v.27 no.3
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    • pp.553-568
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    • 2022
  • In this paper, we introduce and study two different iterative hybrid projection algorithms for solving a fixed point problem of nonexpansive mappings. The first algorithm is generated by the combination of the inertial method and the hybrid projection method. On the other hand, the second algorithm is constructed by the convex combination of three updated vectors and the hybrid projection method. The strong convergence of the two proposed algorithms are proved under very mild assumptions on the scalar control. For illustrating the advantages of these two newly invented algorithms, we created some numerical results to compare various numerical performances of our algorithms with the algorithm proposed by Dong and Lu [11].

PESA: Prioritized experience replay for parallel hybrid evolutionary and swarm algorithms - Application to nuclear fuel

  • Radaideh, Majdi I.;Shirvan, Koroush
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3864-3877
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    • 2022
  • We propose a new approach called PESA (Prioritized replay Evolutionary and Swarm Algorithms) combining prioritized replay of reinforcement learning with hybrid evolutionary algorithms. PESA hybridizes different evolutionary and swarm algorithms such as particle swarm optimization, evolution strategies, simulated annealing, and differential evolution, with a modular approach to account for other algorithms. PESA hybridizes three algorithms by storing their solutions in a shared replay memory, then applying prioritized replay to redistribute data between the integral algorithms in frequent form based on their fitness and priority values, which significantly enhances sample diversity and algorithm exploration. Additionally, greedy replay is used implicitly to improve PESA exploitation close to the end of evolution. PESA features in balancing exploration and exploitation during search and the parallel computing result in an agnostic excellent performance over a wide range of experiments and problems presented in this work. PESA also shows very good scalability with number of processors in solving an expensive problem of optimizing nuclear fuel in nuclear power plants. PESA's competitive performance and modularity over all experiments allow it to join the family of evolutionary algorithms as a new hybrid algorithm; unleashing the power of parallel computing for expensive optimization.

A Novel Hybrid Algorithm Based on Word and Method Ranking for Password Security

  • Berker Tasoluk;Zuhal Tanrikulu
    • International Journal of Computer Science & Network Security
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    • v.23 no.3
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    • pp.161-168
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    • 2023
  • It is a common practice to use a password in order to restrict access to information, or in a general sense, to assets. Right selection of the password is necessary for protecting the assets more effectively. Password finding/cracking try outs are performed for deciding which level of protection do used or prospective passwords offer, and password cracking algorithms are generated. These algorithms are becoming more intelligent and succeed in finding more number of passwords in less tries and in a shorter duration. In this study, the performances of possible password finding algorithms are measured, and a hybrid algorithm based on the performances of different password cracking algorithms is generated, and it is demonstrated that the performance of the hybrid algorithm is superior to the base algorithms.

A Hybrid Learning Model to Detect Morphed Images

  • Kumari, Noble;Mohapatra, AK
    • International Journal of Computer Science & Network Security
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    • v.22 no.6
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    • pp.364-373
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    • 2022
  • Image morphing methods make seamless transition changes in the image and mask the meaningful information attached to it. This can be detected by traditional machine learning algorithms and new emerging deep learning algorithms. In this research work, scope of different Hybrid learning approaches having combination of Deep learning and Machine learning are being analyzed with the public dataset CASIA V1.0, CASIA V2.0 and DVMM to find the most efficient algorithm. The simulated results with CNN (Convolution Neural Network), Hybrid approach of CNN along with SVM (Support Vector Machine) and Hybrid approach of CNN along with Random Forest algorithm produced 96.92 %, 95.98 and 99.18 % accuracy respectively with the CASIA V2.0 dataset having 9555 images. The accuracy pattern of applied algorithms changes with CASIA V1.0 data and DVMM data having 1721 and 1845 set of images presenting minimal accuracy with Hybrid approach of CNN and Random Forest algorithm. It is confirmed that the choice of best algorithm to find image forgery depends on input data type. This paper presents the combination of best suited algorithm to detect image morphing with different input datasets.

Estimation of Optimal Control Parameters and Design of Hybrid Fuzzy Controller by Means of Genetic Algorithms (유전자 알고리즘에 의한 HFC의 최적 제어파라미터 추정 및 설계)

  • Lee, Dae-Keun;Oh, Sung-Kwun;Jang, Sung-Whan;Kim, Yong-Soo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.11
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    • pp.599-609
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    • 2000
  • The new design methodology of a hybrid fuzzy controller by means of the genetic algorithms is presented. First, a hybrid fuzzy controller(HFC) related to the optimal estimation of control parameters is proposed. The control input for the system in the HFC combined PID controller with fuzzy controller is a convex combination of the FLC's output and PID's output by a fuzzy variable, namely, membership function of weighting coefficient. Second, an auto-tuning algorithms utilizing the simplified reasoning method and genetic algorithms is presented to automatically improve the performance of hybrid fuzzy controller. Especially, in order to auto-tune scaling factors and PID parameters of HFC using GA, three kinds of estimation modes such as basic, contraction, and expansion mode are effectively utilized. The proposed HFC is evaluated and discussed to show applicability and superiority with the and of three representative processes.

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Incorporating RSA with a New Symmetric-Key Encryption Algorithm to Produce a Hybrid Encryption System

  • Prakash Kuppuswamy;Saeed QY Al Khalidi;Nithya Rekha Sivakumar
    • International Journal of Computer Science & Network Security
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    • v.24 no.1
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    • pp.196-204
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    • 2024
  • The security of data and information using encryption algorithms is becoming increasingly important in today's world of digital data transmission over unsecured wired and wireless communication channels. Hybrid encryption techniques combine both symmetric and asymmetric encryption methods and provide more security than public or private key encryption models. Currently, there are many techniques on the market that use a combination of cryptographic algorithms and claim to provide higher data security. Many hybrid algorithms have failed to satisfy customers in securing data and cannot prevent all types of security threats. To improve the security of digital data, it is essential to develop novel and resilient security systems as it is inevitable in the digital era. The proposed hybrid algorithm is a combination of the well-known RSA algorithm and a simple symmetric key (SSK) algorithm. The aim of this study is to develop a better encryption method using RSA and a newly proposed symmetric SSK algorithm. We believe that the proposed hybrid cryptographic algorithm provides more security and privacy.

The Design of Hybrid Fuzzy Controller Based on Parameter Estimation Mode Using Genetic Algorithms (유전자 알고리즘을 이용한 파라미터 추정모드기반 하이브리드 퍼지 제어기의 설계)

  • 이대근;오성권;장성환
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2000.05a
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    • pp.228-231
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    • 2000
  • A hybrid fuzzy controller by means of the genetic algorithms is presented. The control input for the system in the HFC is a convex combination of the FLC's output in transient state and PlD's output in steady state by a fuzzy variable. The HFC combined a PID controller with a fuzzy controller concurrently produces the better output performance than any other controller. A auto-tuning algorithms is presented to automatically improve the performance of hybrid fuzzy controller using genetic algorithms. The algorithms estimates automatical Iy the optimal values of scaling factors, PID parameters and membership function parameters of fuzzy control rules. Especially, in order to auto-tune scaling factors and PID parameters of HFC using GA three kinds of estimation modes are effectively utilized. The HFCs are applied to the second process with time-delay. Computer simulations are conducted at step input and the performances of systems are evaluated and also discussed in ITAE(Integral of the Time multiplied by the Absolute value of Error ) and other ways.

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Hybrid Case-based Reasoning and Genetic Algorithms Approach for Customer Classification

  • Kim Kyoung-jae;Ahn Hyunchul
    • Journal of information and communication convergence engineering
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    • v.3 no.4
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    • pp.209-212
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    • 2005
  • This study proposes hybrid case-based reasoning and genetic algorithms model for customer classification. In this study, vertical and horizontal dimensions of the research data are reduced through integrated feature and instance selection process using genetic algorithms. We applied the proposed model to customer classification model which utilizes customers' demographic characteristics as inputs to predict their buying behavior for the specific product. Experimental results show that the proposed model may improve the classification accuracy and outperform various optimization models of typical CBR system.

Improvement and Performance Analysis of Hybrid Anti-Collision Algorithm for Object Identification of Multi-Tags in RFID Systems (RFID 시스템에서 다중 태그 인식을 위한 하이브리드 충돌방지 알고리즘의 개선 및 성능 분석)

  • Choi, Tae-Jeong;Seo, Jae-Joon;Baek, Jang-Hyun
    • IE interfaces
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    • v.22 no.3
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    • pp.278-286
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    • 2009
  • The anti-collision algorithms to identify a number of tags in real-time in RFID systems are divided into the anti-collision algorithms based on the Framed slotted ALOHA that randomly select multiple slots to identify the tags, and the anti-collision algorithms based on the Tree-based algorithm that repeat the questions and answer process to identify the tags. In the hybrid algorithm which is combined the advantages of these algorithms, tags are distributed over the frames by selecting one frame among them and then identified by using the Query tree frame by frame. In this hybrid algorithm, however, the time of identifying all tags may increase if many tags are concentrated in a few frames. In this study, to improve the performance of the hybrid algorithm, we suggest an improved algorithm that the tags select a specific group of frames based on the earlier bits of the tag ID so that the tags are distribute equally over the frames. By using the simulation and mathematical analysis, we show that the suggested algorithm outperforms traditional hybrid algorithm from the viewpoint of the number of queries per frame and the time of identifying all tags.

Design of Fuzzy Logic Controller for Optimal Control of Hybrid Renewable Energy System (하이브리드 신재생에너지 시스템의 최적제어를 위한 퍼지 로직 제어기 설계)

  • Jang, Seong-Dae;Ji, Pyeong-Shik
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.67 no.3
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    • pp.143-148
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    • 2018
  • In this paper, the optimal fuzzy logic controller(FLC) for a hybrid renewable energy system(HRES) is proposed. Generally, hybrid renewable energy systems can consist of wind power, solar power, fuel cells and storage devices. The proposed FLC can effectively control the entire HRES by determining the output power of the fuel cell or the absorption power of the electrolyzer. In general, fuzzy logic controllers can be optimized by classical optimization algorithms such as genetic algorithms(GA) or particle swarm optimization(PSO). However, these FLC have a disadvantage in that their performance varies greatly depending on the control parameters of the optimization algorithms. Therefore, we propose a method to optimize the fuzzy logic controller using the teaching-learning based optimization(TLBO) algorithm which does not have the control parameters of the algorithm. The TLBO algorithm is an optimization algorithm that mimics the knowledge transfer mechanism in a class. To verify the performance of the proposed algorithm, we modeled the hybrid system using Matlab Tool and compare and analyze the performance with other classical optimization algorithms. The simulation results show that the proposed method shows better performance than the other methods.