• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.1
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• pp.45-59
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• 2013

A long-term forecasting method for a new product in early stage of diffusion is proposed. The method includes a constrained non-linear least square estimation with the logistic diffusion model. The constraints would be critical market informations such as market potential, peak point, and take-off. Findings on 20 cases having almost full life cycle are that (i) combining any market information improves the forecasting accuracy, (ii) market potential is the most stable information, and (iii) peak point and take-off information have negative effect in case of overestimation.

• Structural Engineering and Mechanics
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• v.36 no.1
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• pp.95-110
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• 2010

Two-dimensional elastic contact problems, including normal, tangential, and rolling contacts, are treated with the finite element method in this study. Stress boundary conditions and kinematic conditions are transformed into multiple point constraints for nodal displacements in the finite element method. Upon imposing these constraints into the finite element system equations, the calculated nodal stresses and nodal displacements satisfy stress and displacement contact conditions exactly. Frictional and frictionless contacts between elastically identical as well as elastically dissimilar materials are treated in this study. The contact lengths, sizes of slip and stick regions, the normal and the shear stresses can be found.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.621-629
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• 2019

In this paper, we present a local convergence analysis of a three point method with convergence order $1.839{\ldots}$ for approximating a locally unique solution of a nonlinear operator equation in setting of Banach spaces. Using weaker hypotheses than in earlier studies, we obtain: larger radius of convergence and more precise error estimates on the distances involved. Finally, numerical examples are used to show the advantages of the main results over earlier results.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.15-24
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• 2020

With the development of the chemical industry, the chemical accident is increasing every year, thereby increasing the risk of accidents caused by chemicals. The Ministry of Environment provides the criteria for determining shelter-in-place or outdoor evacuation by material, duration of accident, and distance from the toxic substance leak. However, it is hard to say that the criteria for determining the transition point are not clear. Transition point mean the time that evacuation method is switched from shelter-in-place to outdoor evacuation. So, the purpose of this study was to calculate appropriate transition point by comparing the cumulative toxic load. Namdong-gu in Incheon Metropolitan City was finally selected as the target area, considering the current status of the population of Incheon Metropolitan City in 2016 and the statistical survey of chemicals in 2016. The target materials were HCl, HF, and NH₃. Modeling was simulated by ALOHA and performed assuming that the entire amount would be leaked for 10 min. Residents' evacuation scenarios were assumed to be shelter-in-place, immediate outdoor evacuation, and outdoor evacuation at an appropriate time after shelter-in-place. Based on the above method, the appropriate transition point from residents located in A(800 m away), B(1,200 m away), C(1,400 m away) and D(2,200 m away) was identified. In HCl, appropriate transition point was after 15 min, after 16 min, after 17 min, after 20 min in order by A, B, C and D. In HF, appropriate transition point was before 1 min or after 16 min, before 4 min or after 19 min, before 5 min or after 20 min, before 14 min or after 26 min in order by A, B, C and D. In NH₃, appropriate transition point at A was before 4 min or after 16. Others are not in chemical cloud. This study confirmed the transition point to minimize the cumulative toxic load can be obtained by quantitative method. Through this, it might be possible to select evacuation method quantitatively that cumulative toxic load are minimal. In addition, if the shelter-in-place is maintained without transition to outdoor evacuation, the cumulative toxic load will increase more than outdoor evacuation. Therefore, it was confirmed that actions to reduce the concentration of chemicals in the room were necessary, such as conducting ventilation after the chemical cloud passed through the site.

• Journal of Fashion Business
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• v.5 no.4
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• pp.89-100
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• 2001

The major purpose of this study is to show exact and convenient devices and minimize error in body measurement. This study was referred to 13 records and compared 6 items that the investigator's opinion has been differed about anthropometric point and line and suggested convenient and radical device, and measured by if need be. The 30 students from 20 to 25 ages were measured and data was analyzed by mean, std. deviation and paired t-test. The results are as follows. 1. Side neck point has been suggested many devices, but was suggested in this study to decide by M. trapezius, cervicale point and fossa jugularis point. 2. Shoulder point was suggested to decide by point of 1/2 armhole depth, upper arm depth and shoulder depth except acromion point. 3. Waist circumference line has been differed between horizontal line and natural line. The result of measurements was no significant difference between two methods and natural line was convenience. Waist circumference line must considered two methods together for garment construction and somato type. 4. The standard of hip circumference line has been differed between buttock point and trochanterion point. The result of measurements was significant difference between two methods, but two point must considered together because of body type. 5. Chest circumference line at scye has been differed between horizontal line and natural line. The result of measurements was significant difference between two methods and natural line was convenience. Chest circumference line at scye must studied to decide method the line for garment construction.

• Nonlinear Functional Analysis and Applications
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• v.29 no.1
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• pp.225-258
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• 2024

In this paper, we study the problem of finding a common solution to a fixed point problem involving a finite family of ρ-demimetric operators and a split monotone inclusion problem with monotone and Lipschitz continuous operator in real Hilbert spaces. Motivated by the inertial technique and the Tseng method, a new and efficient iterative method for solving the aforementioned problem is introduced and studied. Also, we establish a strong convergence result of the proposed method under standard and mild conditions.

• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.357-370
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• 2014

This study aims to develop a rainfall field tracking method for depth-area-duration (DAD) analysis and assess whether the proposed tracking methods are able to properly estimate the maximum average areal rainfall (MAAR) within the study area during a rainfall period. We proposed three different rainfall field tracking algorithms (Box-tracking, Point-tracking, Advanced point-tracking) and then applied them to the virtual rainfall field with 1hr duration and also compared DAD curves of each method. In addition, we applied the three tracking methods and a traditional GIS-based tool to the typhoon 'Nari' rainfall event of the Yongdam-Dam watershed and then assess applicability of the proposed methods for DAD analysis. The results showed that Box-tracking was much faster than the other two tracking methods in terms of searching for the MAAR but it was impossible to describe rainfall spatial pattern during its tracking processes. On the other hand, both Point-tracking and Advanced point-tracking provided the MAAR by considering the spatial distribution of rainfall fields. In particular, Advanced point-tracking estimated the MAAR more accurately than Point-tracking in the virtual rainfall field, which has two rainfall centers with similar depths. The proposed automatic rainfall field tracking methods can be used as effective tools to analyze DAD relationship and also calculate areal reduction factor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.4
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• pp.191-197
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• 2021

To calculate the induced charge of atoms in molecular dynamics, linear equations for the induced charges need to be solved. As induced charges are determined at each time step, the process involves considerable computational costs. Hence, an efficient method for calculating the induced charge distribution is required when analyzing large systems. This paper introduces the Uzawa method for solving saddle point problems, which occur in linear systems, for the solution of the Lagrange equation with constraints. We apply the accelerated Uzawa algorithm, which reduces computational costs noticeably using the Schur complement and preconditioned conjugate gradient methods, in order to overcome the drawback of the Uzawa parameter, which affects the convergence speed, and increase the efficiency of the matrix operation. Numerical models of molecular dynamics in which two gold nanoparticles are placed under external electric fields reveal that the proposed method provides improved results in terms of both convergence and efficiency. The computational cost was reduced by approximately 1/10 compared to that for the Gaussian elimination method, and fast convergence of the conjugate gradient, as compared to the basic Uzawa method, was verified.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1763-1766
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• 2003

Millimeter-wave networking is composed of narrow beam link. it is very substantial that beam connecting point to point is fixed in right direction. It is major requirement in the beam network to keep the beam in best direction. In this paper, We propose the method to find a best suited direction of the antenna's beam using the Genetic Algorithm (GA) in point-to-point link. Proposed method presume that each station knows his direction ${\theta}_1$ , ${\theta}_2$ at every step of GA, then it can be expected that GA is possible to search the ideal solution. Intensity of the received signal is evaluated by the multiplication of lengths to the point which the lobe meets with the horizontal line.

• Transactions of the Korean Society of Mechanical Engineers
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• v.2 no.2
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• pp.47-51
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• 1978

In order to improve the hitting rate in the shot of rifles, it is required that the analysis of exterior ballistics and the line of sight. One of the important factors influenced a marksman using a rifle obtained the zero-setting of a rifle at the horizontal range, is the deviation of the impact point from the aiming point when the shooting is performed in an inclined ranges. The deviation usually cccurs from the reaction force along the bore line, the characteristics of exterior ballistics, and the error of a shooting range judgement by the inclined range. This study is concerned with the problem of the vertical difference between the impact and aiming point in the inclined shooting ranges. The computing method to find the vertical difference is represented. This method is applied for and experimental rifle in three cases, (1) hofizontal shooting ranges, (2) upper inclined shooting ranges, and (3) lower inclined shooting ranges.