• Journal of Korean Society of Rural Planning
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• v.17 no.3
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• pp.1-13
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• 2011

This study aims to analyse the landscape ecological characteristics of 39 rural villages in Korea and classify them according to their characteristics. After producing a land-use map of rural villages, this study quantified the landscape ecological characteristics of the subject sites as 18 landscape indexes using Fragstats. By applying the landscape index as a variable, selecting 4 factor through principal component analysis and conducting a cluster analysis, it classified them into 3 groups. Rural villages of Korea have their unique types of land-use due to the influence of physical environment such as geography, climate and ecology as well as the social and cultural influence, and the characteristics of land-use can be analysed and classified using the landscape index, the quantified landscape ecological characteristics.

• Journal of the Korean Institute of Navigation
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• v.25 no.4
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• pp.461-469
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• 2001

The purpose of this paper is the optimum modification of dynamic characteristics of stiffened plate structure including the number of stiffener. This paper shows the optimum structural modification method by dynamic sensitivity analysis and quasi-least squares method and considers it's validity. In the method of the optimization, finite element method, sensitivity analysis and optimum structural modification method are used. The change of natural frequency and total weight are made to be an objective function. Thickness of plate, the number of stiffener and cross section moment of stiffener become a design variable. The dynamic characteristics of stiffened plate structure is analyzed using finite element method. Next, rate of change of dynamic characteristics by the change of design variable is calculated using the sensitivity analysis. Then, amount of change of design variable is calculated using optimum structural modification method. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate structure including the number of stiffener.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.58-64
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• 2016

In this paper, the design of rotor shape was performed for improvement of start-up characteristics and efficiency in single-phase LSPM. In order to improve the start-up characteristics, shape of rotor aluminium cage bar was changed. Through arrangement of permanent magnets and installation of flux barriers, it was performed torque ripple reduction and efficiency improvement. Cogging torque and back-EMF is calculated by the no-load analysis, start-up time is calculated by the start-up state analysis, efficiency and torque ripple is calculated by steady state analysis. The characteristics of the motor were calculated through FEM.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.747-756
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• 2007

The hydropneumatic suspension units, which have applied to the tracked vehicles, have the spring and damping function in the unit. The nonlinear characteristics such as roadwheel rotation effects, gas behavior changes, hydraulic damping characteristics, hysterisis, and frictional forces have been ignored or simplified to analyze the mathematical models in many areas. This study describes the dynamic characteristics and the nonlinear behaviors of hydropneumatic suspension unit considering the nonlinear effects such as the nonlinear spring and nonlinear damping through the simulation and the experiment. The utility of nonlinear analysis through the higher-order spectral analysis is also presented.

• Journal of the Korean Wood Science and Technology
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• v.26 no.2
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• pp.29-37
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• 1998

An image analysis program with the function of measuring various quantitative characteristics in the transverse surface of wood was developed using Delphi 2.0. Data on pore characteristics (conditions for image processing, proportion of pores in relationship to other elements, tangential diameter, area, tangential and radial diameter, x and y coordinates of pore center, and geometric coefficients) were saved in text file format. In addition, the pore area histogram in the tangential and radial directions was saved as a BMP (bitmap) type file. Analyses indicated that quantitative characteristics such as the relative radial distribution of pores in a growth ring, pore tangential area histogram, and proportion of pore in lumen area appear to be useful in separating four diffuse-porous woods and four ring-porous woods on the species level.

• Journal of Families and Better Life
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• v.19 no.2
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• pp.111-127
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• 2001

The purposes of this study were to investigate the relationships between individuals characteristics (socio-economic status, time pressures, resources related with implementing housework), attitudes toward goods characteristics, and the level of market goods substitution of housework in the domain of foods and clothes. For empirical analysis, the data of the study was collected from 572 married women living in Seoul. Covariance structure analysis were employed for data analysis, using LISREL. The major findings were as follows: 1) Individuals characteristics, attitudes toward market goods characteristics, and the level of goods substitution of housework had causal relationships. 2) Generally, wifes age and resources related with implementing housework were negative predictors of the level of market goods substitution of housework and wifes education, income, time pressures, attitudes toward characteristics of market goods were positive predictors. Wifes employment was a constraint of Korean traditional sauce, clothes repairing service and laundry service purchases, but a facilitator of the level of dining-out.

• The Journal of the Acoustical Society of Korea
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• v.1 no.1
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• pp.82-91
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• 1982

To analyze the characteristics of engine exhaust mufflers by the acoustic theory is necessary for understanding the action of mufflers and for designing the mufflers. In many cases, the " Transmission Loss" is used in the analysis, but TL is not suitable for above purposes. In this paper the characteristics of the mufflers is analyzed by means of the four terminal constants of whole muffler system. After some approximation, the characteristics of engine exhaust mufflers is shown by the "D" in the four terminal constants. 20log│D│ can be easily constructed with the characteristics of each element of the muffler system. The analysis is done under the conditions of no loss and no gas-flow, so the result is approximate. But it is very useful for understanding the characteristics of the muffler system or each element of the system and for designing the muffler system.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.121-128
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• 2020

This paper presents an experimental study on the dynamic characteristics of infilled reinforced concrete (RC) frames. A 1/3-scaled, one-bay, three-storey RC frame was produced and tested by using operational modal analysis (OMA). The experiments were performed on five specimens: one reference frame with no infill walls and four frames with infill walls. The RC frame systems included infill walls made of hollow clay brick, which were constructed in four different patterns. The dynamic characteristics of the patterns, including the frequency, mode shapes and damping ratios in the in-plane direction, were obtained by 6 accelerometers. Twenty-minute records under ambient vibration were collected for each model, and the dynamic characteristics were determined using the ambient vibration testing and modal identification software (ARTeMIS). The experimental studies showed that the infill walls significantly affected the frequency value, rigidity and damping ratio of the RC frame system.

• Journal of the Korean Society of Safety
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• v.26 no.1
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• pp.36-42
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• 2011

This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an maligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil-structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach.

• Transactions of Materials Processing
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• v.12 no.7
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• pp.654-661
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• 2003

A monobloc TDS(Tube Drive Shaft) has been developed by using the rotary swaging process which is one of the incremental forming process. In order to estimate the developed TDS performance characteristics such as natural frequency, strength, stiffness and mass, finite element analysis has been carried out using commercial software, MSC/NASTRAN. The calculated performance characteristics have been compared with analysis results of SDS(Solid Drive Shaft) to know how much improve the performance characteristics. Also the sensitivity analyses of design parameters for the tube length and diameter have been performed. From the analysis results, it was found that the TDS allowed for a high frequency and could be designed to be much lighter than SDS. This advantage can give possibility to tune the NVH (Noise-Vibration-Harshness) characteristics.