• Title/Summary/Keyword: Optimization Technique

Search Result 2,689, Processing Time 0.043 seconds

A Novel Dynamic Optimization Technique for Finding Optimal Trust Weights in Cloud

  • Prasad, Aluri V.H. Sai;Rajkumar, Ganapavarapu V.S.
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.16 no.6
    • /
    • pp.2060-2073
    • /
    • 2022
  • Cloud Computing permits users to access vast amounts of services of computing power in a virtualized environment. Providing secure services is essential. There are several problems to real-world optimization that are dynamic which means they tend to change over time. For these types of issues, the goal is not always to identify one optimum but to keep continuously adapting to the solution according to the change in the environment. The problem of scheduling in Cloud where new tasks keep coming over time is unique in terms of dynamic optimization problems. Until now, there has been a large majority of research made on the application of various Evolutionary Algorithms (EAs) to address the issues of dynamic optimization, with the focus on the maintenance of population diversity to ensure the flexibility for adapting to the changes in the environment. Generally, trust refers to the confidence or assurance in a set of entities that assure the security of data. In this work, a dynamic optimization technique is proposed to find an optimal trust weights in cloud during scheduling.

Interactive Multiobjective Decision Making under Fuzzy Environment (Fuzzy 환경하에서의 상호작용적 다목적 의사결정)

  • 이상완;김재연
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.13 no.22
    • /
    • pp.51-57
    • /
    • 1990
  • A new interactive multiobjective decision making technique, which is called the fuzzy sequential proxy optimization technique, has been proposed. This technique is the revised version the sequential proxy optimization technique that the decision-maker's marginal rates of substitution is interpreted as type of L-R fuzzy numbers. It used to the square of normalized scalar product as the doptimalilry condition. However, this technique ignores the imprecise nature of a decision-maker's judgement of marginal rates of substitution. Also, it have a shortcoming that can be only applied over three objective functions. In this paper, considering the imprecise nature of a decision-maker's judgement, we presents an interactive fuzzy decision-making method on the basis of the decision-maker's MRS presented through the use of five types of membership functions including non-linear functions. FORTRAN programs that run in conversational mode are developed to implement man-machine interactive procedure.

  • PDF

Multi-Objective Integrated Optimal Design of Hybrid Structure-Damper System Satisfying Target Reliability (목표신뢰성을 만족하는 구조물-감쇠기 복합시스템의 다목적 통합최적설계)

  • Ok, Seung-Yong;Park, Kwan-Soon;Song, Jun-Ho;Koh, Hyun-Moo
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.12 no.2
    • /
    • pp.9-22
    • /
    • 2008
  • This paper presents an integrated optimal design technique of a hybrid structure-damper system for improving the seismic performance of the structure. The proposed technique corresponds to the optimal distribution of the stiffness and dampers. The multi-objective optimization technique is introduced to deal with the optimal design problem of the hybrid system, which is reformulated into the multi-objective optimization problem with a constraint of target reliability in an efficient manner. An illustrative example shows that the proposed technique can provide a set of Pareto optimal solutions embracing the solutions obtained by the conventional sequential design method and single-objective optimization method based on weighted summation scheme. Based on the stiffness and damping capacities, three representative designs are selected among the Pareto optimal solutions and their seismic performances are investigated through the parametric studies on the dynamic characteristics of the seismic events. The comparative results demonstrate that the proposed approach can be efficiently applied to the optimal design problem for improving the seismic performance of the structure.

A teaching learning based optimization for truss structures with frequency constraints

  • Dede, Tayfun;Togan, Vedat
    • Structural Engineering and Mechanics
    • /
    • v.53 no.4
    • /
    • pp.833-845
    • /
    • 2015
  • Natural frequencies of the structural systems should be far away from the excitation frequency in order to avoid or reduce the destructive effects of dynamic loads on structures. To accomplish this goal, a structural optimization on size and shape has been performed considering frequency constraints. Such an optimization problem has highly nonlinear property. Thus, the quality of the solution is not independent of the optimization technique to be applied. This study presents the performance evaluation of the recently proposed meta-heuristic algorithm called Teaching Learning Based Optimization (TLBO) as an optimization engine in the weight optimization of the truss structures under frequency constraints. Some examples regarding the optimization of trusses on shape and size with frequency constraints are solved. Also, the results obtained are tabulated for comparison. The results demonstrated that the performance of the TLBO is satisfactory. Additionally, TLBO is better than other methods in some cases.

APPLICATION OF A GENETIC ALGORITHM FOR THE OPTIMIZATION OF ENRICHMENT ZONING AND GADOLINIA FUEL (UO2/Gd2O3) ROD DESIGNS IN OPR1000s

  • Kwon, Tae-Je;Kim, Jong-Kyung
    • Nuclear Engineering and Technology
    • /
    • v.44 no.3
    • /
    • pp.273-282
    • /
    • 2012
  • A new effective methodology for optimizing the enrichment of low-enriched zones as well as gadolinia fuel ($UO_2/Gd_2O_3$) rod designs in PLUS7 fuel assemblies was developed to minimize the maximum peak power in the core and to maximize the cycle lifetime. An automated link code was developed to integrate the genetic algorithm (GA) and the core design code package of ALPHA/PHOENIX-P/ANC and to generate and evaluate the candidates to be optimized efficiently through the integrated code package. This study introduces an optimization technique for the optimization of gadolinia fuel rod designs in order to effectively reduce the peak powers for a few hot assemblies simultaneously during the cycle. Coupled with the gadolinia optimization, the optimum enrichments were determined using the same automated code package. Applying this technique to the reference core of Ulchin Unit 4 Cycle 11, the gadolinia fuel rods in each hot assembly were optimized to different numbers and positions from their original designs, and the maximum peak power was decreased by 2.5%, while the independent optimization technique showed a decrease of 1.6% for the same fuel assembly. The lower enrichments at the fuel rods adjacent to the corner gap (CG), guide tube (GT), and instrumentation tube (IT) were optimized from the current 4.1, 4.1, 4.1 w/o to 4.65, 4.2, 4.2 w/o. The increase in the cycle lifetime achieved through this methodology was 5 effective full-power days (EFPD) on an ideal equilibrium cycle basis while keeping the peak power as low as 2.3% compared with the original design.

System Optimization Technique using Crosscutting Concern (크로스커팅 개념을 이용한 시스템 최적화 기법)

  • Lee, Seunghyung;Yoo, Hyun
    • Journal of Digital Convergence
    • /
    • v.15 no.3
    • /
    • pp.181-186
    • /
    • 2017
  • The system optimization is a technique that changes the structure of the program in order to extract the duplicated modules without changing the source code, reuse of the extracted module. Structure-oriented development and object-oriented development are efficient at crosscutting concern modular, however can't be modular of crosscutting concept. To apply the crosscutting concept in an existing system, there is a need to a extracting technique for distributed system optimization module within the system. This paper proposes a method for extracting the redundant modules in the completed system. The proposed method extracts elements that overlap over a source code analysis to analyze the data dependency and control dependency. The extracted redundant element is used to program dependency analysis for the system optimization. Duplicated dependency analysis result is converted into a control flow graph, it is possible to produce a minimum crosscutting module. The element extracted by dependency analysis proposes a system optimization method which minimizes the duplicated code within system by setting the crosscutting concern module.

AN ACCELERATED DEFLATION TECHNIQUE FOR LARGE SYMMETRIC GENERALIZED EIGENPROBLEMS

  • HYON, YUN-KYONG;JANG, HO-JONG
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.3 no.1
    • /
    • pp.99-106
    • /
    • 1999
  • An accelerated optimization technique combined with a stepwise deflation procedure is presented for the efficient evaluation of a few of the smallest eigenvalues and their corresponding eigenvectors of the generalized eigenproblems. The optimization is performed on the Rayleigh quotient of the deflated matrices by the aid of a preconditioned conjugate gradient scheme with the incomplete Cholesky factorization.

  • PDF

A new evolutionary programming technique (여러 부집단을 이용한 새로운 진화 프로그래밍 기법)

  • 임종화;황찬식;한대현;최두현
    • Proceedings of the IEEK Conference
    • /
    • 1998.06a
    • /
    • pp.893-896
    • /
    • 1998
  • A new evolutionary programming technique using multiple subpopulations with completely differnt evolution mechanisms is propsed to solve the optimization problems. Three subpopulations, each has different evolution charcteristics and uses different EP algorithms such as SAEP, AEP and FEP, are cooperating with synergy effect in which it increases the possibility to quickly find the global optimum of continuous optimization problems. Subpopulations evolve in differnt manner and the interaction among these leads to global minimum quickly.

  • PDF

Optimization for PSC Box Girder Bridges Using Design Sensitivity Analysis (설계 민감도 해석을 이용한 PSC 박스거더교의 최적설계)

  • 조선규;조효남;민대홍;이광민;김환기
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2000.10a
    • /
    • pp.205-210
    • /
    • 2000
  • An optimum design algorithm of PSC box girder bridges using design sensitivity analysis is proposed in this paper. For the efficiency of the proposed algorithm, approximated reanalysis techniques using design sensitivity analysis are introduced. And also to save the numerical efforts, an efficient reanalysis technique through approximated structural responses is proposed. A design sensitivity analysis of structural response is executed by automatic differentiation(AD). The efficiency and robustness of the proposed algorithm, compared with conventional algorithm, is successfully demonstrated in the numerical example.

  • PDF