• Earthquakes and Structures
• /
• v.10 no.4
• /
• pp.867-891
• /
• 2016

This paper addresses numerically the behavior of steel structures under Fire-after-Earthquake (FAE) loading. The study is focused on a four-storey library building and takes into account the damage that is induced in structural members due to earthquake. The basic objective is the assessment of both the fire-behavior and the fire-resistance of the structure in the case where the structure is damaged due to earthquake. The combined FAE scenarios involve two different stages: during the first stage, the structure is subjected to the ground motion record, while in the second stage the fire occurs. Different time-acceleration records are examined, each scaled to multiple levels of the Peak Ground Acceleration (PGA) in order to represent more severe earthquakes with lower probability of occurrence. In order to study in a systematic manner the behavior of the structure for the various FAE scenarios, a two-dimensional beam finite element model is developed, using the non-linear finite element analysis code MSC-MARC. The fire resistance of the structure is determined using rotational limits based on the ductility of structural members that are subjected to fire. These limits are temperature dependent and take into account the level of the structural damage at the end of the earthquake and the effect of geometric initial imperfections of structural members.

• Journal of Korean Neurosurgical Society
• /
• v.53 no.2
• /
• pp.118-120
• /
• 2013

We report a rare case of remote cerebellar hemorrhage after intradural disc surgery at the L1-2 level. Two days after the spine surgery, patient complained unexpected headache, dizziness, nausea and vomiting. From the urgently conducted brain CT, it was reported that the patient had cerebellar hemorrhage. Occipital craniotomy and hematoma evacuation was performed, and hemorrhagic lesion on the right cerebellum was effectively removed. After occipital craniotomy, the patient showed signs of improvement on headache, dizziness, nausea and vomiting. He was able to leave the hospital after two weeks of initial operation without any neurological deficit. Remote cerebellar hemorrhage following spinal surgery is extremely rare, but may occur from dural damage of spinal surgery, accompanied with cerebrospinal fluid leakage. Early diagnosis is particularly important for the optimal treatment of remote cerebellar hemorrhage.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1643-1648
• /
• 2009

The braking system of train must posses the large baking effort in order to stop the train safety within the limited traveling distance. but, the excessive braking effort has been deteriorated the ride comfort due to high level of deceleration and jerk, and sometimes occurred the skid. because the applied braking force exceeds the allowable adhesive force. this skid causes not only to increase the a stopping distance but also to deteriorate the safety of train and damage the rall surface by wheel flat. In the present paper, braking force for disk brake of Tilting Train eXpress(TTX) was measured though on convention line test and the traction force was estimated by using the analytic model in skid condition. also, we have discussed the relationship between the bake force and traction force in starting condition.

• Earthquakes and Structures
• /
• v.22 no.6
• /
• pp.561-570
• /
• 2022

It is of great importance to be able to evaluate different structural systems not only based on their seismic performance but also considering their lifetime service costs. Many structural systems exist that can meet the engineering requirements for different performance levels; therefore, these systems shall be selected based on their economic costs over time. In this paper, two structural systems, including special steel moment-resisting and the ordinary concentric braced frames, are considered, which are designed to meet the three performance levels: Immediate Occupancy (IO), Life Safety (LS), Collapse Prevention (CP). The seismic behavior of these two systems is studied under three strong ground motions (i.e., Tabas, Bam, Kajour earthquake records) using the Perform3D package, and the incurred damages to the studied systems are examined at two hazard levels. Economic analyses were performed to determine the most economical structural system to meet the specified performance level requirements, considering the initial cost and costs associated with damages of an earthquake that occurred during their lifetime. In essence, the economic lifetime study results show that the special moment-resisting frames at IO and LS performance levels are at least 20% more economical than braced frames. The result of the study for these building systems with different heights designed for different performance levels also shows it is more economical from the perspective of long-term ownership of the property to design for higher performance levels even though the initial construction cost is higher.

• Journal of Ocean Engineering and Technology
• /
• v.36 no.3
• /
• pp.181-193
• /
• 2022

This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.

• Korean journal of applied entomology
• /
• v.47 no.2
• /
• pp.127-131
• /
• 2008

Ambrosia beetle, Platypus koryoensis, is a vector of oak wilt disease caused by Raffaelea sp. in Korea. The degree of damage by oak wilt disease was dependent on the density of the beetles in the oak trunk, a relationship between the degree of damage by oak wilt disease and the density of beetle on the basis of the number of entry hole was studied. Entry hole distribution within tree trunk was analyzed by the nearest neighbor method. Thirty four oak trees (Quercus mongolica) located in survey area were selected and then degree of damage, the number of attack hole/$623cm^2$ in upper (50cm from the surface) and lower (surface) trunk and the nearest neighbor distance between the holes were measured. The number of hole and the nearest neighbor distance in upper and lower part were positively correlated with each other. As the degree of damage was severer, the number of the holes increased, whereas the nearest neighbor distance decreased. The distribution pattern of the hole was changed from clumped one to uniform as the severity of damage increased. These results suggested that Platypus koryoensis attacked the oak tree in concentrative manner at initial stage of attack but at final stage, it distributed uniformly to reduce intraspecific competition between the beetles.

• Physical Therapy Rehabilitation Science
• /
• v.3 no.2
• /
• pp.119-124
• /
• 2014

Objective: The use of chemicals for building prosthetic sockets present the possibility of being hazardous and unsafe due to off-gassing. The purpose of the present study was to investigate if freshly made materials used in prosthetic sockets causes off-gassing that would penetrate the skin and cause damage to the kidneys or blood. Design: Cross-sectional study. Methods: In this research, the off-gassing effects during the initial curing process of styrene monomer, vinyl ester resin, epoxy methacrylate resin, benzene-1, 3-dimethaneamine, trimethylhexanedlamine, and paratertiarybutylphenol were analyzed. Acid detection strips were placed inside newly fabricated mock-prosthetic sockets and left overnight in a closed environment to find out if acid was present in the invisible fumes. The plastic was worn by 9 subjects and urinalysis was made after 48 hours to test for any kidney or blood toxicity of the resins. Results: After wearing the plastic cuff for 48 hours, the ratio of protein to creatinine in the urine was raised to an abnormal level in five out of nine subjects. Four out of the nine subjects showed normal protein to creatinine ratios after wearing the device. The results showed that damage to the kidney occurred from wearing the resins after curing in half of the subjects. Conclusions: It is very important to conduct patient intakes which includes the assessment of renal function. Off-gassing in vented chambers may be needed to protect both prosthetists and patients.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.335-337
• /
• 2021

Flood damage is occurring all over the world, and the number of people living in flood-prone areas reached 86 million, a 25% increase compared to 2000. These floods cause enormous damage to life and property, and it is essential to decide on an appropriate evacuation in order to reduce the damage. Evacuation in anticipation of a flood also incurs a lot of cost, and if an evacuation is not performed due to an error in the flood prediction, a greater cost is incurred. Therefore, in this paper, we propose a flood risk determination model using the CNN model to enable evacuation at an appropriate time by using the time series data of precipitation and water level. Through this, it is thought that it can be utilized as an initial study to determine the time of flood evacuation to prevent unnecessary evacuation and to ensure that evacuation can be carried out at an appropriate time.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.11
• /
• pp.25-31
• /
• 1996

In this paper, three different types of commercial tools -P20, NC123K and ceramic- have been used to cut austempered ductile iron(ADI). In the austempered condition the materials are hard, strong and difficult to machine. Thus, we selected a optimum tool material among three different types of used tools in machining of austempered ductile iron. It was used acoustic emission (AE) to know cutting characteristic for selected tool and investigate characteristic of AE signal according to cutting condition and relationship between AE signal and flank wear land of the ceramic tool. The obtained results are as follows ; (1) The ceramic tool among three different types of tools is the best in machining austempered ductile iron. (2) In case of ceramic tool, the amplitude level of AE signal(AErms) is mainly affected by cutting condition and it is proportional to cutting speed. (3)There have been the relationship of direct proportion between the amplitude level of AE signal and flank wear land of the tool. (4) It was observed that the value of AErms was only affected by cutting speed. Therefore it is possible to in-process detec- tion of ceraic tool's wear in case the initial value of AErms at each cutting speed decided.

• Journal of Nutrition and Health
• /
• v.36 no.6
• /
• pp.603-612
• /
• 2003

Postmenopausal women are at an increased risk of developing coronary artery disease. This is due to primarily dyslipidemia accompanying the loss of estrogen secretion. Soy isoflavones are known to have weak estrogenic effects. The purpose of this study is to investigate whether isoflavone supplement improves the risk of cardiovascular disease in hypercholesterolemic postmenopausal women. Subjects consisted of 39 Korean postmenopausal women with hypercholesterolemia (total cholesterol $\geq$ 200 mg/㎗ or LDL cholesterol $\geq$ 130 mg/㎗). Subjects were divided into 2 groups; placebo group (PG), isoflavone supplement group (IG). During 12 weeks, subjects were given placebo and 80mg isoflavone daily. Anthropometric measurement, blood sample analysis and dietary intake measurement were taken at baseline and after 12 weeks. After 12 weeks, systolic blood pressure was decreased significantly (p ＜ 0.01) and plasma HDL cholesterol level was increased significantly (p ＜ 0.05) in IG. But there were no significant changes in plasma total cholesterol, LDL cholesterol and triglyceride levels after isoflavone supplementation. There was a negative correlation between initial plasma HDL cholesterol level and the extent of plasma HDL cholesterol reduction in IG (r＝-0.572, p＝0.012). Atherogenic index (AI), total-/LDL- cholesterol ratio and LDL/HDL cholesterol ratio were improved significantly after isoflavone supplementation. In subjects whose initial plasma LDL cholesterol level were above 160 mg/㎗, plasma malondialdehyde (MDA) level were decreased and total antioxidant status (TAS) were increased significantly after isoflavone supplement (p ＜ 0.05). However there were no significant changes in flow-mediated dilator (FMD), the marker of endothelium-dependent vasodilation and nitroglycerine-mediated dilator (NMD), the marker of endothelium-independent vasodilation and the extent of DNA damage after isoflavone supplement. In conclusion, these results indicate that isoflavone supplement may decrease the risk of cardiovascular disease via improving blood pressure, HDL cholesterol level and AI in hypercholesterolemic postmenopausal women. Futhermore, in case of subjects with elevated LDL cholesterol level, isoflavone supplementation may have more antiatherogenic effects via improving antioxidant status.