• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.84-90
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• 2018

We researched the way to minimize the damage when the chlorine-leak accident take place in a purification plant. Since the level of risk based on the Off-site Risk Assessment(ORA) is a combination of proportional to the number of residents in the damaged area and frequency of accidents, we suggested the adequate conditions to reduce the number of residents in the damaged area by means of the operating temperature of a handling facility, installation of a emergency shut-off valve, and the analysis of the variation of the damaging range in accordance with the type of enclosure. The coverage of damage was calculated by the 'KORA(Korea Off-site Risk Assessment Supporting Tool) program. The research shows that the lower operating temperature gets, the more emergency shut-off valve being installed and the higher enclosure level of facility becomes, the extent of damage gets decreased. The decreasing rate of worst case was 17.6%, 71%, 34.5% respectively, the decreasing rate of alternative case was 31.6%, 69.0%, 34.8% respectively.

• Journal of Biosystems Engineering
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• v.27 no.5
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• pp.391-398
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• 2002

During handling unitized products, they are subjected to a variety of environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization of pallets has been resulted in a reduction of the shock hazards. This has caused an increasing interest in research focused on vibration caused dam age. Damage to the product by the vibration most often occurs when a product or a product component has a natural frequency that falls within the range of the forcing frequencies of the particular mode of transportation being used. Transportation vibration is also a major cause of fruit and vegetable quality loss due to mechanical damage. This study was conducted to determine the vibration characteristics of the corrugated fiberboard bones for packages of pears, and to investigate the degree of vibration injury of the pears in the boxes during the simulated transportation environment. The vibration tests were performed on an electrohydraulic vibration exciter. The input acceleration to exciter was fixed at 0.25 G for a single container resonance test and 0.5 G for the vertical stacked container over the frequency range from 3 to 100 Hz. Function generator (HP-33120A) was connected by wire to the vibration exciter for controlling the input acceleration at a continuous logarithmic sweep rate of 1.0 octave per min. The peak frequency and acceleration on the single box test were 22.02 Hz, 1.5425 G respectively, and these values on the vertical stacked boxes were observed from the bottom box 19.02, 18.14, 16.62 and 15.40 Hz and 2.2987, 3.7654. 5.6087, and 7.9582 G, respectively. The pear in the bottom box had a slightly higher damage level than the fruit packed in the other stacked boxes. It is desirable that the package and transportation system has to be so designed that 15∼20 Hz frequency will not occur during the transportation environment.

• Fire Science and Engineering
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• v.23 no.3
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• pp.110-120
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• 2009

In tunnel, though the frequency of fire occurrence is relatively lower than other structures, the characteristics of sealed space tends to cause the temperature to rapidly rise to more than $1000^{\circ}C$ within 5minutes after fire, which might eventually lead to a large fire that usually results in a loss of lives and the damage to the properties, not to mention a huge cost necessary for repair and maintenance after fire. We have developed various conditions of the heating furnace and the method to install a thermo couple within the furnace based on EFNARC and KS F 2257-1. Referring to tunnel fire scenarios, it clarified the heat transfer characteristics of concrete PC panel lining depending on fire intensity (ISO, $1^{\circ}C$/SEC, MHC, RWS), and to identify the range of thermal damage, the evaluation was carried out using ITA standard. As a result, 30mm under ISO fire condition, 20mm under $1^{\circ}C$/SEC, 100mm under MHC and 50mm under RWS were measured. And when it comes to spalling, 30mm was measured under RWS and MHC.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.123-133
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• 1998

As the results of investigation, the noise level was between 60 dB and 80 dB in the area of explosion. The residents living within 1 Km would feel uncomfortable. However, hearing loss is not happened by this range. The maximum range that the human can hear is 20,000 Hz and the maximum range that the dog can hear is between 20 Hz and 40,000 Hz. The auditory range for humans to be uncomfortable toward noise is between 1,000 Hz and 2,000 Hz. As the result of this experiment, the auditory range of dog is more wide than of a human. The change of hair cells in the Corti's organ occurred when the dog was exposed to 1,000 Hz at 100 dB for 1 month. Therefore, the structure change of the ear could happen by hearing loss because of noise, but the structure change of hair cells is the worst symptom by hearing loss because of noise.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1149-1159
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• 2018

This study aims to predict the future flood damage cost of 113 middle range watersheds using 26 GCM outputs, hourly maximum rainfall, 10-min maximum rainfall, number of days of 80 mm/day, daily rainfall maximum, annual rainfall amount, DEM, urbanization ratio, population density, asset density, road improvement ratio, river improvement ratio, drainage system improvement ratio, pumping capacity, detention basin capacity and previous flood damage costs. A constrained multiple linear regression model was used to construct the relationships between the flood damage cost and other variables. Future flood damage costs were estimated for different RCP scenarios such as 4.5 and 8.5. Results demonstrated that rainfall related factors such as annual rainfall amount, rainfall extremes etc. widely increase. It causes nationwide future flood damage cost increase. Especially the flood damage cost for Eastern part watersheds of Kangwondo and Namgang dam area may mainly increase.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1043-1050
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• 2020

In this study, a study was presented on the monitoring technique of landslide area using UAV. In the case of disaster investigation using drone mapping, it can be used at various disaster sites. The mission can be carried out at various disaster sites, including surveys of damage to mountainous areas caused by landslides, building collapses surveys of flood damage, typhoons, earthquakes. The damage investigation plan using drone mapping is expected to be highly utilized at disaster sites where investigators cannot access it like in mountainous areas and where it is difficult to conduct direct damage investigations at the site. Drone mapping technology has many advantages in terms of disaster follow-up, such as recovery. Compared to the existing survey system, which was mainly carried out manually, the investigation time can be drastically reduced, and it can also respond to disaster sites that are difficult to carry out or are difficult to access directly. In addition, it is possible to establish and guide spatial data at the disaster site based on accurate mapping data from the time of the disaster, which has considerable strength in managing the situation of the disaster site, selecting priority areas for recovery, and establishing recovery plans. As such, drone mapping is a technology that can be used in a wide range of sites along with natural disasters and social disasters. If a damage investigation system is established through this, it is believed that it will contribute significantly to the rapid establishment of recovery plans along with the investigation of disaster response time and extent of damage recovery.

• Structural Engineering and Mechanics
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• v.45 no.3
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• pp.391-410
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• 2013

A numerical method is presented here to detect and assess structural damages from changes in natural frequencies using Ant Colony Optimization (ACO) algorithm. It is possible to formulate the inverse problem in terms of optimization and then to utilize a solution technique employing ACO to assess the damage/damages of structures using natural frequencies. The laboratory tested data has been used to verify the proposed algorithm. The study indicates the potentiality of the developed code to solve a wide range of inverse identification problems in a systematic manner. The developed code is used to assess damages of beam like structures using a first few natural frequencies. The outcomes of the simulated results show that the developed method can detect and estimate the amount of damages with satisfactory precision.

• Journal of Environmental Impact Assessment
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• v.17 no.6
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• pp.381-391
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• 2008

The instances of the damage to livestock are increasing with frequent environmental disputes on the noise and vibration. This study analyzed 134 open cases dealing with the environmental disputes on livestock damaged by noise and vibration, and being intervened by National Environmental Dispute Resolution Commission. The environmental disputes on the noise and vibration account for 86% of all the disputes, and cases of the consequent damages to livestock have increased. As shown in the 134 cases, pig is the most lethal livestock attacked by the noise and vibration. During last 10 years, 89% of the noise damages hurting the livestock resulted from the noises pertaining to construction and 58% was due to the noise damages from the road constructions. The noise levels in the range of 70~80 dB(A) and the vibration levels of 70~75 dB(V) caused most of the disputes. The average rate of reimbursement for the livestock damages for the last 10 years was higher than the average rate of reimbursement of the total disputes intervened by National Dispute Resolution Commission.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.184-187
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• 2005

Physical changes in a structural system may cause changes in mechanical impedance of the system. Due to the electro-mechanical coupling effect in piezoelectric materials, this change can be monitoring by the electrical impedance of the piezoelectric sensor. In this paper, the variability of electro-mechanical impedance caused by temperature effect is assessed to adjust impedance data used for EMI based damage detection in beams. First experiments on beams are described. Next, experiments were performed under the temperature varying condition, in the range of $3^{\circ}C\;to\;23^{\circ}C$. Finally, the relationship between temperatures and impedance signatures is analyzed empirically temperature-frequency patten for the test structure.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.28.1-28.1
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• 2011

Radiation-induced displacement damage which has caused the increase of the dark current in the focal plane adopted in the Ozone Monitoring Instrument (OMI) was studied in regards of the primary protons and the secondaries generated by the protons in the orbit. By using the Monte Carlo N-Particle Transport Code System (MCNPX) version 2.4.0 along with the Stopping and Range of Ions in Matter version 2010 (SRIM2010), effects of the primary protons as well as secondary particles including neutron, electron, and photon were investigated. After their doses and fluxes that reached onto the charge-coupled device (CCD) were examined, displacement damage induced by major sources was presented.