• Journal of the Korean Professional Engineers Association
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• v.17 no.3
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• pp.6-21
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• 1984

A rock slide in amount of 100 tons in weight happened at 7: 10 a.m., 4th October 1982, on the southwestern ridge of Mt. Seunghag, Busan City. The original rock mass of the rock slide is located 850m west from the Dangri Crushed Stone Quarry. The geology of the area consists of agglomerate, andesite, andesitic tuff, and shale hornfels of the Cretaceous Yucheon Group. The rock blocks were first shifted along the steep joint plane on an andesite outcrop at the site and then to the eastern foot of the mountain slope where some private houses are placed. The mountain slope is covered with thick superficial soil. A slided monolithic-block with 83 tons in weight from the rock slide met with an accident of striking against a house with a tremendous force, to which much damage was done as much as its half was destroyed. The rock-slided block pierced the board-floored room only posited at the center and by the bedroom of the house making a pass like a bullet hole, and hence cut a big pine tree with 24 centimeters in diameter at a distance of 26 meters down the house. However nobody was killed or injured in the stricken house, though seven family members were stayed therein at the very time of accident. They really met a rare opportunity in an unhappy disaster. Measurements of the rock slide were made in the course of the field survey. The monolithic mass was transported by way of saltation, rolling, and sliding to a distance of 300 meters down along the slope dipping 30$^{\circ}$ east. It took about 16 seconds front tile outcrop to the terminal. The acceleration value of the monolithic rock slide is 2.35m/sec$^2$.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.447-455
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• 2018

If a hidden enemy is shooting, there is a threat against soldiers in recent conflicts. This paper aims to improve the localization of a muzzle using microphone array. Gunshot noise can provide information about the location of muzzle with two signals, the muzzle blast from the gun barrel and the projectile sound from the bullet. Two signals arrive to the microphone array with different arrival time and angle. If the arrival angles of the two signals are estimated, distance between sniper location and the microphone array can be calculated by using geometric principles. This method was established in 2003 by Pare. But this method has a limitation that it cannot calculate the distance when the arrival angles of the two signals are same. Also it has an error when the angle difference of arrival is small. In order to overcome this limitation, a new method is proposed that uses the change of characteristic of the projectile sound with respect to vertical distance from the trajectory. The proposed method estimates the distance correctly when the arrival angle of two signals are same, and when the angle difference between two signals is increased, the estimation error increases with respect to the angle. Therefore these two methods can be selected according to the angle difference between two signals to estimate the distance of the muzzle. Below the threshold of the angle difference, the proposed method can be used to estimate distance with smaller error than the existing method. This was demonstrated by shooting tests using actual sniper rifles.

• Korean journal of communication and information
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• v.42
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• pp.107-139
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• 2008

With the rapid change of broadcasting industry, the dominant market power of Korean free TV is going down. The purpose of this study is to estimate what is their strategy to recover the actual difficulties as for advertising media and production company. We will focus on mainly their horizontal diversification, MPP(multiple program provider). They will be classified and analysed by 5 portfolio types of Aaker: Cashcow Brand, flanker Brand, Strategic Brand, Silver Bullet Brands and Branded Energizer. For this, we will study the data from Korean Broadcasting Committee, home page of each channels, etc. At result, since MPP(multiple program provider), affiliates of Korean free TV have the stable advertising revenues compared with other cable channels, there are many cases of Cashcow brands which need few supplementary investment from the parental company and influence positively for the other channel brands.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.255-259
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• 2008

This study was investigated antioxidant and anticancer activity of water, methanol extract from upper and root part of Taraxacum mongolicum H. Total phenolic compound contents of methanol and water extracts from upper part were $51.95{\pm}0.18$ mg/g and $48.16{\pm}0.89$ mg/g respectively, and total flavonoid compound contents were estimated as $20.57{\pm}1.12$ mg/g in methanol extract and $6.55{\pm}1.20$ mg/g in water extract. $EC_{50}$ values for DPPH radical scavenging activity of methanol and water extract from upper part were $138.47{\pm}3.78{\mu}g/mL$ and $204.38{\pm}5.32{\mu}g/mL$, and methanol and water extracts from root part were as $512{\pm}8.11{\mu}g/mL$ in methanol extract and $1315.05{\pm}11.98{\mu}g/mL$ in water extract. Reducing power and hydroxyl radical $({\bullet}OH)$ scavenging activity estimated that methanol extract of each part were higher than water extracts. The cell viability showed that the methanol extract from upper part had a cytotoxicity in the growth of colon carcinoma cell (44.58%). Both water extract $(51.97{\pm}11.43%)$ from upper part and methanol $(53.46{\pm}19.77%)$, water $(52.79{\pm}13.53%)$ extracts from root part had quite higher cytotoxicity than that of methanol extract $(88.25{\pm}2.02%)$ from upper part. Based on the results, It was suggested that the methanol extract of Taraxacum mongolicum H. were potential materials for use as functional food and medicine.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.611-615
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• 2015

Anti-aircraft gun system is used for low-level air defense system and has more than twin guns with high firing rate in order to maximize the capability of defense. Gun's vibration and bullet's variance has a critical effect on accuracy and hit probability of weapon system such as anti-aircraft gun system with high firing rate. Typical mechanism to reduce the amount of vibration and shock during gun-fire process is very important design factor. In this paper, the suspension characteristics of the vehicle are studied for the improvement of isolating performance of gun firing system with high firing rate. Gun fire test for the vehicle is conducted and computational models using Recurdyn and Adams are created based on test results. Through this study, results of computational analysis are compared with the real test results, which includes type, location and quantity of suspension and gun mechanism are selected for anti-aircraft gun. From the result of this study, we could make basic design and consider the proper component of the system such as suspension and gun spring.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1577-1583
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• 2012

Penetrator with enhanced lateral effect (PELE) is a novel projectile that does not require dynamite and a fuse. It comprises a high-density jacket that is closed at its rear end and filled with a low-density filling material. To study the explosion characteristics of PELE using AUTODYN-3D code, the calculation models of the projectile body and the bullet target were developed and the process of penetrating an aluminum-2024 alloy target using PELE was simulated. The scattering characteristics after PELE penetrated the aluminum-2024 alloy target were studied for different filling materials. The explicit finite element analysis of PELE fragmentation was implemented with the stochastic failure criterion in AUTODYN-3D code. As the filling expanded, the fragments gained velocity and dispersed laterally, increasing the damage area considerably. The number and shape of PELE fragments differed depending on the impact pressure of the filling that fragmented during the penetration and lateral dispersion processes.

• Journal of Trauma and Injury
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• v.31 no.2
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• pp.82-86
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• 2018

Craniocerebral gunshot injuries (CGIs) are extremely seldom happened in Korea because possession of individual firearm is illegal. So, CGIs are rarely encountered by Korean neurosurgeons or Korean trauma surgeons, though in other developing countries or Unites states of America their cases are indefatigably increasing. Management goal should focus on early aggressive, vigorous resuscitation. The treatments consist of immediate life salvage through correction of coagulopathy, intracranial decompression, prevention of infection and preservation of nervous tissue. There have been few studies involving penetrating CGIs in Korea. Here we present a case of penetrating gunshot wound in Korea. We present a 58-year-old man who was unintentionally shot by his colleague with a shotgun. The patients underwent computed tomography (CT) for assessment of intracranial injury. The bullet passed through the left parietal bone and right lateral ventricle and exited through the posterior auricular right temporal bone. After CT scan, he arrested and the cardiopulmonary resuscitation was conducted immediately. But we were unable to resuscitate him. This case report underscores the importance of the initial clinical exam and CT studies along with adequate resuscitation to make the appropriate management decision. Physicians should be familiar with the various injury patterns and imaging findings which are poor prognostic indicators.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.187-190
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• 2015

An 18-month-old female spayed domestic short-haired cat, weighing 4.1 kg, was presented as an emergency case after it suffered a gunshot injury. Physical examination of the cat revealed paraplegia, with loss of deep nociception. A bullet (diameter, 3 mm) lodged in the left epaxial muscle at the level of the first lumbar (L1) was observed on radiographic examination, and a hyperattenuating spot in the spinal canal was confirmed using computed tomography. Exploratory laminectomy was performed, and an incomplete fracture of the right caudal articular process of L1 and a necrotizing spinal cord lesion were found. The animal was euthanized and necropsy was performed, which revealed a crack on the left pedicle of L1. This case report presents the first detailed clinical description of a gunshot injury to the spinal cord in a cat.

• Applied Microscopy
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• v.41 no.2
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• pp.117-122
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• 2011

Sperm morphology of Pipistrellus savii velox was examined by transmission electron microscope. The sperm head of P. savii velox was bullet in shape. The sperm head was 3.1 ${\mu}m$ in length, whose posterior 3.0 ${\mu}m$ was occupied by a nucleus with 1.8 ${\mu}m$ in width. The segmented columns were about 14~15 in number. The total number of mitochondrial gyres was 57. Number of 1, 5, and 6 of the outer dense fibers were larger than the others. A fibrous sheath and longitudinal column of the principal piece were evidence, but the fibrous sheath was not seen at the end piece. In the present study, the length of the sperm head of P. savii velox were very shorter than those of other bats.

• Applied Microscopy
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• v.41 no.1
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• pp.31-35
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• 2011

The fine structures of the sperm morphology in the Myotis daubentonii ussuriensis were observed by transmission electron microscope. The results showed that the sperm head revealed bullet shaped, the width was showed a slender more than toward the posterior region to anterior region of nucleus. The sperm head was about $4.5{\mu}m$ in length, being about $2.0{\mu}m$ in width. The nuclear length was $4.3{\mu}m$, occupied most of the sperm head. The nucleus and acrosome were separated by the apical body. The neck region was composed the basal plate, capitulum and segmented columns. The segmented columns were about 12 to 14 in number and connected with the outer dense fibers of the middle piece. The mitochondria sheath were arranged like the thread of a screw, and the total number of mitochondrial gyres were 57. The satellite fibers were observed irregularly among the outer dense fibers in the middle piece. Except the middle piece they are not observed in the principal and end pieces of the tail. In general, the tail show axoneme composed of a 9+2 microtubular pattern, and microtubules of the end piece were arranged irregularly.