• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.5
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• pp.205-213
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• 2001

This paper presents a virtual instrumentation(VI) system for LIMs performance on-line monitoring. The VI is designed using the graphical programming language LabVIEW and is capable of performing on-line measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. To monitor in real time the steady-state and transient electromagnetic thrust of LIMs, the search coil is used for the determination of the flux linkage components, which is then multiplied by the appropriate current components to yield a signal proportional to the electromagnetic thrust. This paper reports the LIM's dynamics measured by the proposed on-line monitoring system.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.7
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• pp.323-330
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• 2001

Niching method enables the genetic algorithm(GA) to be applied to the problems that require the location of multiple solutions in the search space, but these methods have fatal disadvantages. The main disadvantage is that the method requires too much calculation of object function. In this paper, a niching method using restricted competition selection(RCS) combined with a pattern search method(PSM) is proposed to identify multiple niches more efficiently and fast in a multimodal domain. The validity of the proposed method is verified by the simulation of test functions and the optimal design of an torque motor.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1088-1090
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• 1997

This paper presents an effective methodology of optimal environmental and economic operation using evolution strategy. In power systems, evolution strategy, based on natural selection and genetics, can analyze non-linear and discontinuous functions in global search techniques. The formulation using this search techniques is multi-objective function, which consists of fuel cost and environmental effects concerning the pollution of the Earth's atmosphere caused by the emission of $SO_2$ and $NO_x$ from thermal generator plants. The proposed algorithms are applied on system with 6 generator.

• Journal of Information Technology Services
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• v.2 no.2
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• pp.53-62
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• 2003

Current P2P (Peer-to-Peer) applications have the limited functions such as file search and transfer between peers and have the limitations such as trust problem on search results, copyright problem, and profitable business model problem. For a P2P application to be used as a business platform for the distribution of various multimedia contents, this paper proposes an extended P2P application architecture and its prototype system including distributed collaborative filtering, automated price negotiation system, and payment mechanism.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.597-609
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• 2010

A problem formulation and solution methodology for design optimization of laminated thin-walled composite beams of generic section is presented. Objective functions and constraint equations are given in the form of beam stiffness. For two different problems one for open section and the other for closed section, the objective function considered is bending stiffness about x-axis. Depending upon the case, one can consider bending, torsional and axial stiffnesses. The different search and optimization algorithm, known as Evolution Strategies (ES) has been applied to find the optimal fibre orientation of composite laminates. A multi-level optimization approach is also implemented by narrowing down the size of search space for individual design variables in each successive level of optimization process. The numerical results presented demonstrate the computational advantage of the proposed method "Evolution strategies" which become pronounced to solve optimization of thin-walled composite beams of generic section.

• Journal of Electrical Engineering and Technology
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• v.5 no.1
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• pp.8-15
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• 2010

A new technique using a search method which is based on fuzzy multi-criteria function is proposed for GMS(generator maintenance scheduling) in order to consider multi-objective function. Not only minimization of probabilistic production cost but also maximization of system reliability level are considered for fuzzy multi-criteria function. To obtain an optimal solution for generator maintenance scheduling under fuzzy environment, fuzzy multi-criteria relaxation method(fuzzy search method) is used. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system model in Korea in 2010.

• Korean Journal of Remote Sensing
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• v.23 no.3
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• pp.229-236
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• 2007

Scattered satellite images were collected and converted from TDF to HDF as a standard format. We reviewed all the metadata on the images domestic and abroad and set up the metadata for the meteorological satellite images and naming rules in KMA. The satellite information search system that meteorological satellite images were in service with metadata for public and academic fields was implemented for quick search and download. This system will facilitate satellite images for various academic purposes beyond KMA and management functions of the system make routine workflow to manage satellite images in an ease and standardized way.

• Journal of Magnetics
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• v.18 no.1
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• pp.74-79
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• 2013

This paper proposes a sampling-based optimization method for electromagnetic design problems, where design sensitivities are obtained from the elaborate surrogate models based on the universal Kriging method and a local window concept. After inserting additional sequential samples to satisfy the certain convergence criterion, the elaborate surrogate model for each true performance function is generated within a relatively small area, called a hyper-cubic local window, with the center of a nominal design. From Jacobian matrices of the local models, the accurate design sensitivity values at the design point of interest are extracted, and so they make it possible to use deterministic search algorithms for fast search of an optimum in design space. The proposed method is applied to a mathematical problem and a loudspeaker design with constraint functions and is compared with the sensitivity-based optimization adopting the finite difference method.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3772-3783
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• 2021

This work proposes a new efficient meta-heuristic optimization algorithm called Gamma Ray Interactions Based Optimization (GRIBO). The algorithm mimics different energy loss processes of a gamma-ray photon during its passage through a matter. The proposed novel algorithm has been applied to search for the global minima of 30 standard benchmark functions. The paper also considers solving real optimization problem in the field of nuclear engineering, radioisotope identification. The results are compared with those obtained by the Particle Swarm Optimization, Genetic Algorithm, Gravitational Search Algorithm and Grey Wolf Optimizer algorithms. The comparisons indicate that the GRIBO algorithm is able to provide very competitive results compared to other well-known meta-heuristics.

• The Journal of the Korea Contents Association
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• v.20 no.11
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• pp.644-655
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• 2020

The study examined differences between perceptions of AI speakers and intention to continuous use of AI speakers according to usage function. We divided usage patterns into single- and multi-function orientations based on the usage by different functions of audio content (music, news, and search), and analyzed the differences between perceptions of using AI speakers and the intention to continuous use. 335 men and women who had experience using AI speakers participated in an online survey. Results are as follows. First, men used AI speakers mainly for acquiring news, and the extent to which 20s and 40s acquire news was different. Second, perceptions of usefulness and ease of use were found to be higher in the multi-functional group(music-news-search). Last, regarding the intention to continuous use of AI speakers, the multi-functional group was highest, and users focusing on music listening were relatively higher than users for other functions. The findings of the study are expected to be used as foundational data for expanding the use of AI speakers and developing strategies for service provision in each AI speaker brand.