• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.45-51
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• 2014

Distribution system is a critical link between customer and utility. The control of power loss is the main factor which decides the performance of the distribution system. There are two methods such as (i) distribution system reconfiguration and (ii) inclusion of capacitor banks, used for controlling the real power loss. Considering the improvement in voltage profile with the power loss reduction, later method produces better performance than former method. This paper presents an advanced evolutionary algorithm for capacitor inclusion for loss reduction. The conventional sensitivity analysis is used to find the optimal location for the capacitors. In order to achieve a better approximation for the current candidate solution, Opposition based Differential Evolution (ODE) is introduced. The effectiveness of the proposed technique is validated through 10, 33, 34 and85-bus radial distribution systems.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.4
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• pp.191-196
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• 2015

In this paper, we present a path-smoothing algorithm for a robot arm manipulator that finds the path using a joint space-based rapidly-exploring random tree. Unlike other smoothing algorithms which require complex mathematical computation, the proposed path-smoothing algorithm is done using a Gaussian process. To find the optimal hyperparameters of the Gaussian process, we use differential evolution hybridized with opposition-based learning. The simulation result indicates that the Gaussian process whose hyperparameters were optimized by hybrid differential evolution successfully smoothed the path generated by the joint space-based rapidly-exploring random tree.

• Journal of KIISE:Software and Applications
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• v.26 no.1
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• pp.130-130
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• 1999

In this paper, we propose a novel design method for improving performance of existing FCM-type clustering algorithms. First, we define the performance measure which focuses on bothcompactness and separation of clusters. Next, we optimize this measure using evolution program.Especially the proposed method has following merits: ① using evolution program, it solves suchproblems as initialization, number of clusters, and convergence to local optimum ② it reduces searchspace and improves convergence speed of algorithm since it represents chromosome with possiblepotential centers which are selected possible candidates of centers by density measure ③ it improvesperformance of clustering algorithm with the performance index which embedded both compactnessand separation Properties ④ it is robust to noise data since it minimizes its effect on center search.

• Journal of information and communication convergence engineering
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• v.17 no.4
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• pp.261-266
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• 2019

Differential evolution (DE) is an uncomplicated and serviceable developmental algorithm. Nevertheless, its execution depends on strategies and regulating structures. The combination of several strategies between subpopulations helps to stabilize the probing on DE. In this paper, we propose a unique k-mean soft island model DE(KSDE) algorithm which maintains population diversity through soft island model (SIM). A combination of various approaches, called KSDE, intended for migrating the subpopulation information through SIM is developed in this study. First, the population is divided into k subpopulations using the k-means clustering algorithm. Second, the mutation pattern is singled randomly from a strategy pool. Third, the subpopulation information is migrated using SIM. The performance of KSDE was analyzed using 13 benchmark indices and compared with those of high-technology DE variants. The results demonstrate the efficiency and suitability of the KSDE system, and confirm that KSDE is a cost-effective algorithm compared with four other DE algorithms.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.291-294
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• 2005

The microstructure evolution of Alloy 718 during the direct age(DA) process was predicted using the recrystallization model and finite element analysis. The DA process of Alloy 718 was performed in two-step forging using capsulated cylindrical billets of 122mm in diameter and 180mm in height. In order to evaluate the microstructural change during the forging, a dynamic recrystallization model of Alloy 718 was implemented onto the user-subroutine of the commercial FEM code. The prediction of microstructure evolution in DA processed Alloy 718 pancake was compared with experimental results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.483-486
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• 2005

In order to study the effect of strain states on the formation of shear textures during rolling in fcc metals, the evolution of textures was simulated by the full constrain model using various ideal strain states. Considering rolling as a two-dimensional problem, i.e., $\varepsilon_{22}\;=\;\varepsilon_{12}\;=\;\varepsilon_{23}\;=\;0$, the deviation from the plane-strain state manifest itself as nonzero contribution of $\varepsilon_{13}$. With increasing variations of $\varepsilon_{13}$, shear textures develop. The sign of ell hardly affects the evolution of textures. The texture simulation with various idealized strain states indicates that the ratio $\mid\varepsilon_{13}\mid/\mid\varepsilon_{11}\mid$ in each time interval in a roll gap plays a dominant role in the evolution of textures during rolling.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.408-410
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• 2008

The evolution of texture and microstructure during recrystallization was tracked after different cold rolling of aluminum sheets. Texture of the sheet center were differentiated by different strain states due to prior deformation. The evolution of recrystallization texture was studied with the amount of shear applied during cold rolling. The final grain size after recrystallization annealing was varied due to the effective strain during deformation.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.161-166
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• 2020

The primary aim of this paper is to analyze the resultative adjunct clause, i.e., (thus/thereby/hence) ~ing participle and provide explicit syntactic, semantic and sociolinguistic explanation on the question what causes the cause-focused causal construction with resultative (thus/thereby/hence) ~ing participle in English. What comes first is either cause or effect clause. This study explores the recent style shift of causal constructions from the effect-focused pattern to the cause-focused pattern. In this study, we argue that the increasing number of the cause-focused main clause with a resultative ~ing participle clause shows the process of the style evolution improving speech/wring style in many respects including syntactic simplification, clarification of the sentence meaning with impact on the focused clauses, and improvement of the flow of speech/writing. The style shift found in the English resultative adjunct clauses, i.e., (thus/hence/thereby) ~ing participle constructions prove to be the style evolution from syntactic, semantic and sociolinguistic point of views.

• International Journal of Aerospace System Engineering
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• v.7 no.2
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• pp.6-12
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• 2020

The precise prediction of future position of satellite depends on the accurate determination of orbit, which is also helpful in performing orbit maneuvers and trajectory correction maneuvers. For estimating the orbit of satellite many methods are being used. Some of the conventional methods are based on (i) Differential Correction (DC) (ii) Extended Kalman Filter (EKF). In this paper, Differential Evolution (DE) is used to determine the orbit. Orbit Determination using DC and EKF requires some initial guess of the state vector to initiate the algorithm, whereas DE does not require an initial guess since a wide range of bounds for the design unknown variables (orbital elements) is sufficient. This technique is uniformly valid for all orbits viz. circular, elliptic or hyperbolic. Simulated observations have been used to demonstrate the performance of the method. The observations are generated by including random noise. The simulation model that generates the observations includes the perturbation due to non-spherical earth up to second zonal harmonic term.

• Journal of Korea Technology Innovation Society
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• v.14 no.2
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• pp.320-342
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• 2011

This paper tries to analyze the evolution of technological innovative pattern in system semiconductor industry from the perspective of the evolution of way by which knowledge is generated and its related evolution of inter-firm relationships. In particular, this paper focuses on the evolution of knowledge after the emergence of EDA as a design tool, as a main momentum. As a result of analysis, we can find out following things. First, the innovative activities have evolved from design activity-centered technology development to innovative activities focusing on searching activities for utilizing knowledge and technology. Second, with rising value of knowledge, creation of new market utilizing knowledge, and development of new industry and new technology through inter-firm relationship had been made, in addition to strengthened specialized technological division of labor. Third, with focusing on utilization of knowledge, inter-firm network has taken diverse forms for building complementary platform for co-development. This discussion can give an insight on the necessity of utilizing inter-firm network strategically and setting strategies for enhanced searching activities such as market creation and knowledge utilization.