• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.47-49
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• 2012

Under this study, the characteristics of concrete intensity condition following the curing method under the extremely low temperature environment have been contemplated, and as a result, in the event of insulation + heat cable curing, the intensity and accumulated temperature accomplishment period is required for two times of requiring initial frost damage prevention than the case of heating + heat insulation curing method due to the insufficient calories supplied in general.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.4
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• pp.41-45
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• 1981

This study is to be surveyed the rural environmental conditions such as housing, water works, sewerage, road and farm road, land utilization, natural conservation and sightseeing, public damage and disaster, and rural water requirement through the 50 villages (10995 home unit) The brief results summarized in this study are as follows. 1.Modernization of rural housing, toilet room and arrangement of dust materials are getting better than before l0yrs. 2.Water works are highly improved but sewerage problem is still in the serious problems. 3.Rood achievement is quite good but farm road is in still insufficiency 4.Utilization of land resources should be maximaized but land conservation is still insufficient condition and farm land is getting polluted. 5.Natural environmental conservation is much more improved but landscape is still insufficient. 6.Public damages such as water pollution, air pollution, and others are getting greater and greater but meteorological damage should be decreased. 7.Watershed condition is getting better and better but because of the large requiriment of the water use for the crops, agricultural water use should be needed much more than before l0yrs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.77-82
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• 2004

This study presents reliability assessment of merchant ships with focus on hull girder ultimate limit state, taking into account the time-dependent effects of corrosion, fatigue cracking and local denting. Some considerations for establishing a reliability-based repair and maintenance scheme are also made so as to keep a ship's hull girder strength reliability at an acceptable level even later in life.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.4
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• pp.134-140
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• 2016

Main Spindle System has effect on performance of machine tools and working quality as well as is required of high reliability. Especially, it takes great importance in producing automobiles which includes a large number of working processes. However, main spindle unit in Machine tools are often cases where damage occurs do not meet the design life due to driving in harsh environments. This is when excessive maintenance and repair of machine tools or for damage stability has resulted in huge economic losses. Therefore, this studying propose a method of accelerated life test for diagnosing and prognosis the state of life assessment main spindle system. Time status monitoring of diagnostic data - through the analysis of the frequency band signals were carried out inside the main spindle bearing condition monitoring and fault diagnosis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.178-185
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• 1999

Minimum life-cycle cost helps to evaluate cost effectiveness of base-isolated bridges under specific condition. Life-cycle cost mainly consists of the initial construction cost and the expected damage cost. Damage cost estimation needs proper model of input ground motion failure probability evaluation method and limit states definition. We model the input ground motion as spectral density function compatible with the response spectra defined at each seismicity and site condition. Spectrum analysis and crossing theory is suitable for reseating calculation of failure probabilities in the process of cost minimization. Limit states of base-isolated bridges re defined for superstructure isolator and pier respectively The method is applied to both base-isolated bridges and conventional bridges under the same conditions to investigate cost effectiveness of base isolation in low and moderate seismic region. the results show that base-isolation of bridges are more effective in low and moderate seismic region and that the site effects on the economical efficiency may not be negligible in such a region.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.82-90
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• 1998

Machines that normally operate under fluid film lubricated condition also experience surface damage. This is largely due to the failure of the lubricant film which leads to boundary lubrication. Thus, it is important to have a good understanding of boundary lubrication behavior. In this paper the major tribological parameters that influence the boundary lubrication properties are evaluated. It is shown that disk roughness, hardness and normal load affect the friction and wear of metals in boundary lubrication. Also, the mechanism of surface damage is attributed to abrasion and wear particle interaction.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.97-110
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• 2015

This study aimed to classify damaged lands, to find what are the damage factors affecting the studied area, and to present a prescription in order to provide some benefit for the restoration of Regional Ecological Network at Chungnam province. Finally we classified damaged lands from 1st to 4th damaged lands according to relative intensity of damage. The main damage factors for the First Damage Lands were humus horizon, soil hardness and plant species richness. In the Second Damage Lands, those were soil hardness, plant species richness, number of plants and dominant plant species. In the Third Damage Lands, those were humus horizon, soil hardness, plant species richness, number of plants and dominant plant species. In the Fourth Damage Lands, those were humus horizon, organic matter, soil hardness, EC, T-N content, plant species richness, number of plants and dominant plant species. In every cases, the damage of soil and vegetation was originated due to development carried out by human being. The changes in soil condition were not big enough for it to affect plant growth, however, degradation of vegetation was still severe.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.1
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• pp.33-46
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• 2004

This study is aimed to redesign established parks and to propose a series of devices protecting them from vandalism. To solve the problems, we ascertained the damaged areas of the park greens. The trace analysis was performed to grasp the transverse inside the parks of Jeonju and Iksan in Collabuldo. Then, we presented the basic plan for minimizing park damage and for remodeling the system of movement. The results of the study are summarized as follows: it is identified that the transverse phenomenon is considerably wide-spread in majority of parks, and has no relationship to the park area or the green area. It is considered that the $\ulcorner$Condition rating class$\lrcorner$ of grass damage, which is grade 6, is extraordinarily high and the damage is accumulated considerably. Also, the damage part of other grade is discovered equally, and when unattended, the acceleration of damage is positive. A damage width a 0.5∼1.5m makes up the greater part of 79.6%. It also constitutes most of a rectilinear form. The difference in the height between the original point and destination point is below 0.7m, which is above 70%. It is identified that the interrelationship between the damage continuation length and plan distance is relatively high by the simple regression: analysis and by Pearson' correlation analysis. In spite of the normal damage continuation length is 20m, the frequency degree is downward with extreme point at 10m. Accordingly, it is assumed that park users have physical and psychological pressure when they cross the lawn field. Damage types are classified as the Simple cut cross type, the Behavioral facilitates type, Access advantage type and the Strolling type through type classification. It is considered that this classification is effective when identifying short pass type on lawn field according to the damage length and intensity.

• Smart Structures and Systems
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• v.10 no.3
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• pp.253-269
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• 2012

A split spectrum processing (SSP) method is proposed to accurately determine the time-of-flight (ToF) of damage-scattered waves by comparing the instantaneous amplitude variation degree (IAVD) of a wave signal captured from a damage case with that from the benchmark. The fundamental symmetrical ($S_0$) mode in aluminum plates without and with a notch is assessed. The efficiency of the proposed SSP method and Hilbert transform in determining the ToF of damage-scattered $S_0$ mode is evaluated for damage identification when the wave signals are severely contaminated by noise. Broadband noise can overwhelm damage-scattered wave signals in the time domain, and the Hilbert transform is only competent for determining the ToF of damage-scattered $S_0$ mode in a noise-free condition. However, the calibrated IAVD of the captured wave signal is minimally affected by noise, and the proposed SSP method is capable of determining the ToF of damage-scattered $S_0$ mode accurately even though the captured wave signal is severely contaminated by broadband noise, leading to the successful identification of damage (within an error on the order of the damage size) using a triangulation algorithm.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.2
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• pp.257-270
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• 2000

The objective of this study is to develop a damage model based on damage mechanics that can be used to analyze the mechanical behavior of structures with defects and the global behavior of damaged structures. A modified second order damage tensor that can be applied to finite element analysis is used to reflect the effect of damage. The damage stress computed from the effective stress is considered as an additional loading term acting on nodes and can represent the effect of crack surface. The accuracy of the proposed algorithm is verified by comparing the analysis results with the experimental data from other studies and the analysis results based on transverse isotropic theory. The developed damage model is applied to the analyses of structures with cracks under linear elastic condition. The comparisons confirmed that the quantitative analysis of the structural behavior due to crack orientation and multiple sets of cracks is possible. Also, the damage caused by rock excavation and fault zone is analyzed. The results also showed that the developed model can effectively analyze the global behavior of damaged structures.