• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.8-9
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• 2006

This paper presents a new methodology to calculate an optimal solution of equilibrium to power system differential algebraic equations. It employs a nonlinear interior point method for solving the optimization formulation, which includes dynamic equations representing two-axis synchronous generator models with AVR and speed governing control, algebraic equations, and steady-state nonlinear loads. Equilibrium optimization (EOPT) is useful for diverse purposes in power system analysis and control with consideration of the system frequency constraint.

• ETRI Journal
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• v.32 no.4
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• pp.630-633
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• 2010

In this letter, we propose a novel polygonal approximation of digital curves that preserve original shapes. The proposed method first detects break points, which have two different consecutive vectors, and sets an initial dominant point set. The approximation is then performed iteratively by deleting a dominant point using a novel distance, which can measure both the distance and the angle acuteness. The experimental results show that the proposed method can preserve original shapes and is appropriate for various shapes, including slab-sided shapes.

• Journal of the Korean Institute of Rural Architecture
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• v.12 no.3
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• pp.35-46
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• 2010

The purpose of this study is to interpretate the Korean traditional Private Garden Pavilion -'byoul-seo(別墅)' in the view point of the architectural methodology - the separation of space in Honam province. It is presumed that nature union is archived through the 'yan-sang(玩賞)' which is ultimate state of knowledge that is base on the premises of opened signification in emancipation from narrow view point in the past and cognition of value. therefore, it is needed to know the unworldly point of space perception about the pavilion territory, furthermore to have conceptual method to distinct pavilion from the world. there are two methods in the distinct concept in this pavilion research: unworldly separation and meditative separation. As a result, the followings are conclusions; There two distinctive methods of planning of pavilion by use of the room and column. There are enclosement, turnaround, division of floor area in the room organization method, and it's modification of modulation, diversification of column height and diversification of column use in different space.

• Communications for Statistical Applications and Methods
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• v.24 no.1
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• pp.15-27
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• 2017

This paper introduces a two-parameter discrete distribution based on a continuous two-parameter bathtub distribution. It is the only two-parameter discrete distribution that shows a bathtub-shaped hazard function. Some statistical properties of the distribution are discussed. Three different methods are used to estimate its two unknown parameters. The point estimators of the parameters have no closed form. The bootstrap method is used to estimate the distributions of these point estimators. Different approximations of the interval estimations for the two-parameters are discussed. Real data sets are analyzed to show how this distribution works in practice. A simulation study is performed to investigate the properties of the estimations obtained and compare their performances.

• Journal of Ocean Engineering and Technology
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• v.37 no.3
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.706-712
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• 2014

This paper describes a determining method of weighting factors for two-point interpolation filters. The interpolation filters is implemented by applying modifying functions to the linear interpolation. Here, there is a problem of determining weights when modifying functions being engaged. The previous method determined the weights by imposing c1-continuity on the interpolation kernels. However, this approach is unable to use the property of individual modifying functions. In this paper, on the basis of spectral analyses of the modifying functions and image signals, we provide a determination method by experimental results. Thus, many experiments are carried out to do so. The results indicate that different weights are required for different modifying functions and also the proposed method outperforms than the previous method.

• IE interfaces
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• v.23 no.3
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• pp.257-263
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• 2010

Taguchi defined a good quality as 'A correspondence of product characteristic's expected value to the objective value satisfying the minimum variance condition.' For his good quality, he suggested Taguchi Method which is called Robust design which is irrelevant to the effect of these noise factors. Taguchi Method which has many success examples and which is used by many manufacturing industry. But Optimal solution of Taguchi Method is one among the experiments which is not optimal area of experiment point. On the other hand, Response Surface Method (RSM) which has advantage to find optimal solution area experiments points by approximate polynomial regression. But Optimal of RSM is depended on initial point and RSM can not use many factors because of a great many experiment. In this paper, we combine the Taguchi Method and the Response Surface Method with each advantage which is called Taguchi-RSM. Taguchi-RSM has two step, first step to find first solution by Taguchi Method, second step to find optimal solution by RSM with initial point as first step solution. We give example using catapults.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.3
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• pp.41-56
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• 2000

In this paper, we propose a two-stage fast block matching algorithm using the mean absolute error (MAE) of neighbor search point that can reduce the computational complexity to estimate motion vector while the motion estimation error performance is nearly the same as full search algorithm (FSA) In the proposed method, the lower bound of MAE 6at current search point IS calculated using the MAE of neighbor search point And we reduce the computational complexity by performing the block matching process only at the search point that has to be block matched using the lower bound of MAE The proposed algorithm is composed of two stages The experimental results show that the proposed method drastically reduces the computational complexity while the motion compensated error performance is nearly kept same as that of FSA.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.86-91
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• 2015

The flash point is used to categorize inflammable liquids according to their relative flammability. Such a categorization is important for the safe handling, storage, and transportation of inflammable liquids. The flash point temperature of two binary liquid mixtures(n-octane+n-decane and n-octane+n-dodecane) has been measured for the entire concentration range using Seta-flash closed cup tester based on the ASTM D3278 method. The closed cup flash point temperature was estimated using the UNIFAC(Universal Functional Activity Coefficient) group contribution model. The experimentally derived flash point was also compared with the predicted flash point from the UNIFAC model. The UNIFAC model is able to estimate the flash point fairly well for n-octane+n-decane mixture and n-octane+n-dodecane mixture.

• Journal of the Korean Statistical Society
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• v.31 no.2
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• pp.261-276
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• 2002

Probability density or its derivatives may have a discontinuity/change point at an unknown location. We propose a method of estimating the location and the jump size of the discontinuity point based on kernel type density or density derivatives estimators with one-sided equivalent kernels. The rates of convergence of the proposed estimators are derived, and the finite-sample performances of the methods are illustrated by simulated examples.