• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.53-59
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• 2010

A fatigue damage caused by cyclic load is considered as one of the important failure mechanisms that threaten the integrity of structures and components in a nuclear power plant. In ASME code section III NB, the fatigue analysis procedure and standard S-N curves for the class 1 components are described and these criteria should be met at the design step of components. As the current ASME S-N curves are based on the very conservative assumptions such as a local stress concentration effect, immoderate transient frequencies and a constant Young's modulus, however, they can not precisely address the fatigue behavior of components. In order to find out the technical solution for these problems, a number of researches and discussion have been carried out continuously at home and abroad over the decades. In this study, detailed fatigue analyses for DVI nozzle with various mesh density of finite elements were performed to evaluate effect of stress concentration factors on the fatigue analysis procedure and the excessive conservatism of stress concentration factors are confirmed through the analysis results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.453-462
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• 2002

Discrete-sizing or standardized steel profiles are used in steel design and construction practice. However, most of numerical optimization methods follow additional step(round-up discrete-sizing routine) to use the standardized steel section profiles, and accordingly the optimality of the resulting design nay be doubtful. Thus, in this paper, an efficient multi-level optimization algorithm is proposed to improve the shortcoming of the conventional optimization methods using the round-up discrete-sizing routine. Also, multi-level optimization technique with a decomposition method that separates both system-level and element-level is incorporated in the algorithm to enhance the performance of the proposed algorithms. The proposed algorithm is expected to achieve considerable improvement on both the efficiency of the numerical process and the accuracy of the global optimum.

• Earthquakes and Structures
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• v.7 no.5
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• pp.667-689
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• 2014

Structural walls (also known as shear walls) are one of the common lateral load resisting elements in reinforced concrete (RC) buildings in seismic regions. The performance of RC structural walls in recent earthquakes has exposed some problems with the existing design of RC structural walls. The main issues lie around the buckling of bars, out-of plane deformation of the wall (especially the zone deteriorated in compression), reinforcement getting snapped beneath a solitary thin crack etc. This study compares performance of a typical wall designed by different standards. For this purpose, a case study RC shear wall is taken from the Hotel Grand Chancellor in Christchurch which was designed according to the 1982 version of the New Zealand concrete structures standard (NZS3101:1982). The wall is redesigned in this study to comply with the detailing requirements of three standards; ACI-318-11, NZS3101:2006 and Eurocode 8 in such a way that they provide the same flexural and shear capacity. Based on section analysis and pushover analysis, nonlinear responses of the walls are compared in terms of their lateral load capacity and curvature as well as displacement ductilities, and the effect of the code limitations on nonlinear responses of the different walls are evaluated. A parametric study is also carried out to further investigate the effect of confinement length and axial load ratio on the lateral response of shear walls.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.138-144
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• 1997

Korean agricultural and rural economics has been gotten more difficult through the introduction of economics system under the control of IMF before problems from open market system under WTO get to be settled. Export should be promoted to get the advantage of open market system and to get over today's economic crisis from shortage of foreign currency. Fortunately, Korea adjoins Japan that is largest importing country of agricultural products in a world, therefore Korean Agricultural products has advantage in export to Japan through open market system. Puyo tomato, specialized agricultural products in Chungman province, has been exported 42.2M/T to Japan from 1994 year to 1996 year. But such exported amount was so small that is less than a 1% of total tomato product in Puyo area. Reasons why export volume to Japan was so small were non standard commodities, non performance of export contract, unfavorable price condition, etc.. But it was major reason that missed optimal exporting period. Therefore this study is aimed at finding optimal period exporting Puyo mini tomato to Japan. According to result of analysis based on monthly price and carried quality data of major tomato market between Korea and Japan, it has more comparative advantage that we export tomato during Period of Dec-Feb. rather than March-May which is currently major exporting period.

• Steel and Composite Structures
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• v.3 no.3
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• pp.153-168
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• 2003

This paper discusses the results and observations from a large-scale fire test conducted on a slim floor system, comprising asymmetric beams, rectangular hollow section beams and a composite floor slab. The structure was subjected to a fire where the fire load (combustible material) was higher that that found in typical office buildings and the ventilation area was artificially controlled during the test. Although the fire behaviour was not realistic it was designed to follow as closely as possible the time-temperature response used in standard fire tests, which are used to assess individual structural members and forms the bases of current fire design methods. The presented test results are limited, due to the malfunction of the instrumentation measuring the atmosphere and member temperatures. The lack of test data hinders the presentation of definitive conclusions. However, the available data, together with observations from the test, provides for the first time a useful insight into the behaviour of the slim floor system in its entirety. Analysis of the test results show that the behaviour of the beam-to-column connections had a significant impact on the overall structural response of the system, particularly when the end-plate of one of the connections fractured, during the fire.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.3
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• pp.61-80
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• 2010

Recently, the publishing community now recognizes the importance of metadata in customers' buying decisions. As a result, they are more interested in effective metadata creation and quality maintenance, as well as standardization of exchanging system in the supply chain. As the library community also investigates the economic effectiveness of creating metadata, they try to find the best model for simplifying metadata creation by using sources close to the original. This study analyzes metadata work flow which had same source but be used in different fields by their own type and standard. It also discusses the same issues about each section and possibility about interoperation. Finally this paper tries to find an effective creation and distribution model of book metadata which can be used in domestic publishing and the library community.

• Journal of Fashion Business
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• v.11 no.3
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• pp.35-45
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• 2007

This study examined how to create 2D basic pattern of individuals by means of 3-D body figure, which is to develop a flat of individual basic pattern directly from the 3-D body scan data of each subject using that of the upper body of a male adult. In terms of methodology, this study adopted 3D body scan data on system and body to make examinations in the following steps: 1. Standard point and line were set on human body, along with 3-D definition points(feature points). 2. PB was created by modifying horizontal and longitudinal section of scan data. 3. Ways to set reserve were established in the findings of PB planar development. Respective developed flat patterns were compared with pattern findings in previous studies by means of sensory evaluation. As a result, it was found that both system and body model are basic pattern and belong to appropriate pattern as semi-tight-fit basic pattern with overall appropriate tolerances. Thus, this study came to a conclusion that it is feasible and valid to develop theories for flat development as considered herein.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1782-1791
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• 2017

In this paper, an optimal design of hybrid magnetic levitation(Maglev) system using intelligent optimization algorithms is proposed. The proposed maglev system adopts hybrid suspension system with permanent-magnet(PM) and electro magnet(EM) to reduce the suspension power loss and the teaching-learning based optimization(TLBO) that can overcome the drawbacks of conventional intelligent optimization algorithm is used. To obtain the mathematical model of hybrid suspension system, the magnetic equivalent circuit including leakage fluxes are used. Also, design restrictions such as cross section areas of PM and EM, the maximum length of PM, magnetic force are considered to choose the optimal parameters by intelligent optimization algorithm. To meet desired suspension power and lower power loss, the multi object function is proposed. To verify the proposed object function and intelligent optimization algorithms, we analyze the performance using the mean value and standard error of 10 simulation results. The simulation results show that the proposed method is more effective than conventional optimization methods.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.6
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• pp.832-840
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• 2019

Recently, pollution from gunpowder due to shell shootings at military drilling sites has raised various environmental concerns. The purpose of this study is to predict the contamination level of RDX in the soil area of the firing range zone near Anwol river watershed, the study site, and the intake area, Anwol river and Imjin river, as a function of time and space. In this study, a multimedia model was developed to predict the variation of RDX contamination by rainfall. The range of the medium was limited to soil, water, and sediment, and excluded the atmosphere, taking into account the physical and chemical properties of RDX with low vapor pressure and low Henry's constant. The pollutant levels of the waters of compartments, including the last section of the Imjin River affecting the water intake, was compared with the environmental standard for RDX.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3573-3578
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• 2015

Transition curves are located between curve and straight section in railway. These transition curves are vulnerable to the ride comfort of passengers and safety of a vehicle because lateral acceleration, lateral jerk and roll velocity increase as curvature and cant change along the transition curves. In this paper, ride comfort on the transition curve was calculated on the basis of lateral acceleration and roll velocity measurements. The evaluation of ride comfort was conducted according to the methodology specified in European Standard. The distribution characteristics of the comfort index were investigated for the korean conventional line from the evaluation results. The influence of the curve radius and the vehicle speed on the ride comfort index was also investigated. Finally, the relationship between ride comfort and the rate of cant changes on transition curves was analyzed.