• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.1
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• pp.66-72
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• 1999

In this paper, we suggest a new lifetime allocation method of genetic algorithm with varying population size. This method can control the size of the population according to the fitness values. The population size is stabilized near the neighbourhood of the optimal value. We used the diploidy method in the coding of the chromosomes. Several simulations confirm that the new allocation method can control the size of the population.

• Journal of the Korean Statistical Society
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• v.3 no.1
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• pp.3-12
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• 1974

The two-stage sequential test, suggested by Baker [2] for testing hypotheses $H_0:\mu=\mu_0$ and $H_1:\mu=\mu_1$ of $N(\mu,\sigma^2)$ with the unknown $\sigma^2$ would not be amenable for applications unles some cluses on the choice of the first-stage sample size are available. The study in this paper is intended to shed some light on the size of the first-stage sample. An approximate method is used to estimate an optimal initial sample size that minimizes the average sample number. In brief, the optimal size is a strictly monotone decreasing function of the quantity $(\mu_1-\mu_0)/\sigma$. Empirical and simulation results are used to ascertain the negligible effect of possible errors due to approximations and assumptions used.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.55-62
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• 2016

The least-mean fourth (LMF) algorithm is well known for its fast convergence and low steady-state error especially in non-Gaussian noise environments. Recently, there has been increasing interest in the least mean square (LMS) algorithms with variable step size. It is because the variable step-size LMS algorithms have shown to outperform the conventional fixed step-size LMS in the various situations. In this paper, a variable step-size LMF algorithm is proposed, which adopts an algebraic optimal step size as a variable step size. It is expected that the proposed algorithm also outperforms the conventional fixed step-size LMF. The superiority of the proposed algorithm is confirmed by the simulations in the time invariant and time variant channels.

• Journal of the Korean Society of Food Culture
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• v.37 no.4
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• pp.335-344
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• 2022

The study was aimed to investigate the operational meal costs by kindergarten size in Seoul and to analyze recognition for optimal meal prices. A survey (31.6% recovery rate) was conducted on all kindergartens (779 kindergartens) in Seoul on April 2021 using descriptive analysis, t-test, and dispersion method. A price sensitivity measurement (psm) method was used to determine optimal meal prices. Result showed an average food cost for kindergartens of 2,647 won, an average labor cost of 605 won, an average operating cost of 146 won, and the total meal cost of 3,506 won. Total meal cost decreased with increasing kindergarten size (p<0.001). On the other hand, kindergartens with more students decreased the ratio of food cost to total meal cost, and operating cost and labor costs (p<0.001) increased. The optimal price of kindergarten operators' meal cost (OPP) was KRW 3,673. Furthermore, the analysis showed the sensitivity of operators' meal costs to kindergarten size was insignificant.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.369-376
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• 2015

Numerical models simulating groundwater flow are often used to estimate groundwater discharge into a tunnel. In designing numerical models, the grid size should be carefully considered to ensure that groundwater discharge is accurately predicted. However, several recent studies have employed various grid sizes without providing an adequate explanation for their choice. This paper suggests the optimal grid size based on a comparison of numerical models with analytical solutions. Discrepancies between numerical and analytical solutions result from the effect of model boundaries as well as the grid size. By nullifying boundary effects, the errors solely associated with the grid size could be analyzed. The optimal grid size yielding accurate numerical solutions was thus derived. The suggested relationship between tunnel radius and optimal grid size is analogous to the relationship between the equivalent well block radius and grid size.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.918-924
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• 2009

As the population of overweight and obese children is rising rapidly around the world, there are many researches on purchasing and wearing children's clothing and optimal sizes, but researches on obese children are still inadequate. This study was carried out on 192 obese children over 75% in BMI. The purpose of the study was to set up the optimal interval of sizing system using the loss function which would be a guide for obese children for selecting ready to wear of suitable size. Introducing a loss function, which reflects how much the purchasing desire changes according to the difference, we formulate the problem and suggest a procedure to determine the optimal standard sizes minimizing the loss. These results were as follows ; In size chart of top's, 4 sizes had been determined by a loss function, had covered more than 91.1% of all subjects. In size chart of bottom's, 5 sizes had been determined by a loss function, had covered more than 87.0% of all subjects.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.487-497
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• 2010

This paper estimates theoretically optimal sizes of urban population for major metropolitan areas using an urban economy system with utility maximizing household, profit maximizing producer and government providing public goods. This finds that the optimal size of urban population is determined by technological levels and public services. The population sizes of Seoul, Busan, Daegu and Incheon are higher than their optimal levels, while Gwangju, Daejeon and Ulsan need to increase the population for production efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.370-373
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• 1988

Althouah there have been many attempts to control weld quality in resistance spot welding processes, design method for an on-line feedback controller based upon process dynamics has not been suggested. This is due to the fact that the resistance spot welding is a highly complicated process, whice involves the interaction of electrical, thermal, mechanical and metallurgical phenomena. In this paper, an optimal control method based on FDM model with shunt effect is presented, which can regulate the nugget size, at the same time minimizing the control heat input. Optimal PI gain of the controller were determined by numerical optimization. Simulation results show that, as a result of the proposed optimal control, the weld nugget can be made to approach a desired nugget size with less control heat input than that required for the conventional spot welding process in the face of the shunt effect.

• Journal of the Korean housing association
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• v.19 no.6
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• pp.1-8
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• 2008

A fitness facility in an apartment complex is not a simple sports facility. It has important roles in improving the residents' physical and mental health, and in forming a sense of community. This study analyzed the number of users in the fitness facility of the apartment complex, which is a significant criterion in determining the dimension. A comparative analysis between the past and the present function and dimension was performed in finding out the optimal solutions. In conclusion, the number of users in the fitness facility is influenced not by the number of households in the complex but by the facility's size and creating a desired environment. The users' favorite sports equipments were figured out to meet those needs. Moreover, comparing the facilities' size, user satisfaction, area per person, an optimal dimension for the facility, and rates of equipments were found out.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.592-596
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• 2001

Near field technology makes it possible to overcome the diffraction limit of laser beam and create the small spot. Because of the small spot size, the pit size and track pitch can be decreased. So the high performance actuator is needed for near field recording system. And the light mass and the small form factor are also important properties of the NFR actuator in order to be used for hand held device. The purpose of this paper is the optimal design of the NFR coarse actuator to maximize actuating force. The structure of NFR coarse actuator is the same as HDD VCM actuator. The permeance method is used for modeling of the coarse actuator. The optimal result and the FEM simulation result are presented.