• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.397-403
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• 2024

North Korea's rapidly advancing drone development and operational capabilities have become a significant threat to South Korea's security. The drone incursions by North Korea in 2014, 2017, and 2022 demonstrate the technological advancement and provocative potential of North Korean drones. This study aims to closely analyze the military threats posed by North Korean drones and seek effective countermeasures. The research examines the development level of North Korean drone technology, its military applications, the characteristics and patterns of recent drone incursions, the adequacy and limitations of South Korea's current response systems, and future countermeasures. For this purpose, domestic and international research literature and media reports were reviewed, and specific North Korean drone incursion cases were analyzed. The results indicate that North Korea's small drones possess technological features such as small size, low altitude, low-speed flight, long-duration flight, and reconnaissance equipment. These drones pose threats that can be utilized for reconnaissance, surveillance, surprise attacks, and terrorism. Additionally, South Korea's current response systems reveal limitations such as inadequate detection and identification capabilities, low interception success rates, lack of an integrated response system, and insufficient specialized personnel and equipment. Therefore, this study suggests various technical, policy, and international cooperative countermeasures, including the development of drone detection and identification technologies, the utilization of diverse drone neutralization technologies, the establishment of legal and institutional foundations, the construction of a cooperative framework among relevant agencies, and the strengthening of international cooperation. The study particularly emphasizes the importance of raising awareness of the North Korean drone threat across South Korean society and unifying national efforts to respond to these threats.

• Journal of the KSME
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• v.17 no.4
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• pp.235-256
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• 1977

과거일제하에서는 그 식민정책으로 기계공업을 억제하고 경공업에 치중하였다가 1940년대 전쟁 물자 조달과 대륙침략야옥의 필요상 부분적으로 국내 생산을 하게 되었고 따라서 이에 관련된 토목기계, 광석기계, 농기구, 수송기계, 등의 기계공업이 일어나기 시작한 것이다. 그러다가 조국 이 해방된 기쁨은 안았으나 산업의 위축은 더할 나위 없이 되었고, 6,25동난을 당하여 그나마 대 부분 파괴되었던 과거를 가지고 있는 것이다. 그러다가 1960년대 이후 우리나라 경제개발 1,2,3, 차5개년 계획을 수행하여 현재에 이른 것이다. 먼저 기계공업의 특징을 보면 기계공업은 모든 산업의 생산수단인 기계설비 생산하는 산업이며, 그 파급효과는 전 산업에 미친다. 산업구조의 고도화와 산업의 근대화는 기계공업의 발전없이 이루어질 수 없다. 기계공업은 중화학공업에 있 어서 중구적인 산업이니만큼 기계공업의 발전없는 경제성장에는 한계가 있는것이다. 선진공업 국가들은 수출상품중 기계류수출비중이 일반적으로 50%를 전후하고 있다. 기계류는 다른 상품과 달리 단위 거래규모가 크기 때문이다. 다음에 기계공업은 기술집약, 노동집약 현 산업이다. 우리 나라는 비교적 풍부한 노동력을 가지고 있을뿐아니라 이들 인력은 교육수준이 대체로 높다. 그러기 때문에 기술노동집약적인 기계공업은 고용증대를 갖어오는 반면에 높은 교육수준의 풍부 한 노동력을 통한 발전이 기대되고 있다. 특히 기계고업은 국방력강화라는 점에서 큰 역할을 담당하게 된다. 그러므로 기계공업은 국방력 강화의 기초산업이다. 우리나라 현재의 여건으로서 기게공업은 방의산업으로서의 역할이 크게 요청되고 있다. 우리나라의 경제는 수출의 증대를 통 해서 고도의 경제성장을 유지해야 하겠고 80년대의 자립경제 기반을 구축키 위한 공업화 정책을 추진하고 있어서 중화학공업의 핵심산업으로서 기계공학 및 기술의 획기적인 육성과 발전은 우리나라 경제의 당면 과제인 것이다. 보고에서 필자는 여러 문헌들을 통하여 우리나라 기계공업 의 발 자취를 살피고 현향을 소개하며 아울러 대망의 80년대의 우리나라 기계공업을 전망해 보고 저 한다.

• Journal of Chest Surgery
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• v.42 no.2
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• pp.259-262
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• 2009

Surgery on the distal trachea or the carina presents special problems for maintaining the airway and systemic oxygenation. Cardiopulmonary bypass is an alternative method for respiratory support for the patients with these conditions. Percutaneous cardiopulmonary support (PCPS) applied under local anesthesia has recently been used for respiratory support in tracheal surgery and the outcome is satisfactory. We encountered a patient who had severe distal tracheal stenosis after prolonged intubation. We had a gratifying result with performing tracheal resection and repair under the support of PCPS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.417-428
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• 2017

In this paper, we describe the architectural design, unit component hardware design and core software design(Helmet Pose Tracking Software and Terrain Elevation Data Correction Software) of IHDS(Intelligent Helmet Display System), and describe the results of unit test and integration test. According to the trend of the latest helmet display system, the specifications which includes 3D map display, FLIR(Forward Looking Infra-Red) display, hybrid helmet pose tracking, visor reflection type of binocular optical system, NVC(Night Vision Camera) display, lightweight composite helmet shell were applied to the design. Especially, we proposed unique design concepts such as the automatic correction of altitude error of 3D map data, high precision image registration, multi-color lighting optical system, transmissive image emitting surface using diffraction optical element, tracking camera minimizing latency time of helmet pose estimation and air pockets for helmet fixation on head. After completing the prototype of all system components, unit tests and system integration tests were performed to verify the functions and performance.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.73-82
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• 2015

A high altitude test facility which includes supersonic diffuser and ejector has been developed to simulate atmospheric pressure at 25 km using a 500 N class small scale liquid rocket engine. Also high altitude simulation test for the small scale liquid rocket engine was performed to verify the facility's performance. The experimental facility consists of high altitude simulation device, propellants supply system and coolant supply system. Low pressure condition corresponding to about 27 km(0.021 bar) altitude atmosphere was successfully simulated and a small scale liquid rocket engine thrust level was confirmed at the simulated condition by the high altitude test facility verification test.

• Geophysics and Geophysical Exploration
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• v.17 no.1
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• pp.1-10
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• 2014

To reveal and classify site characteristics in densely populated areas in Chuncheon, Korea, Rayleigh-waves were recorded at 50 sites including four sites in the forest area using four 1-Hz velocity sensors and 24 4.5-Hz vertical geophones during the period of January 2011 to May 2013. Dispersion curves of the Rayleigh waves obtained by the extended spatial autocorrelation method were inverted to derive shear-wave velocity ($v_s$) models comprising 40 horizontal layers of 1-m thickness. Depths to weathered rocks ($D_b$), shear wave velocities of these basement rocks ($v_s^b$), average velocities of the overburden layer ($\bar{v}_s^s$), and the average velocity to a depth of 30 m ($v_s30$), were then derived from those models. The estimated values of $D_b$, $v_s^b$, $\bar{v}_s^s$, and $v_s30$ for 46 sites at lower altitudes were in the ranges of 5 to 29 m, 404 to 561 m/s, 208 to 375 ms/s, and 226 to 583 m/s, respectively. According to the Korean building code for seismic design, the estimated $v_s30$ indicates that the lower altitude areas in Chuncheon are classified as $S_C$ (very dense soil and soft rock) or $S_D$ (stiff soil). To determine adequate proxies for $v_s30$, we compared the computed values with land cover, lithology, topographic slope, and surface elevation at each of the measurement sites. Due to a weak correlation (r = 0.41) between $v_s30$ and elevation, the best proxy of them, applications of this proxy to Chuncheon of a relatively small area seem to be limited.

• Journal of agricultural medicine and community health
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• v.38 no.1
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• pp.14-24
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• 2013

Objectives: Pregnant women in rural areas do not have access to sufficient obstetric services in their own communities due to the shortage of obstetricians. Therefore, most of these women must seek obstetrician outside of their communities. The purpose of this study was to investigate the relationship between obstetric complications and accessibility to local obstetric care in Korea. Methods: This study was an ecological study in which the unit of analysis was an administrative district. Using Korea National Health Insurance Corporation data, the total number of deliveries and the delivery proportion within and outside of the community from 2001 to 2008 were calculated for 232 administrative districts nationwide. Three outflow levels were categorized based on each district's out-of-community delivery proportion: high outflow (upper one third), moderate outflow (middle one third), and low outflow (lower one third). In addition, three obstetric complication rates (the rate of complications following abortion, ectopic and molar pregnancy, the abortion rate, and the eclampsia rate) were calculated for the 232 districts. One-way ANOVA and multivariate linear regression were used to evaluate obstetric complications among the three outflow levels. Results: The high outflow districts had higher rates of eclampsia and complications following abortion, ectopic, and molar pregnancy compared to the other districts (ANOVA, p<0.05). However, there was no significant difference in the abortion rate among the three groups. Multiple linear regression analysis showed that high outflow districts were statistically significant in the rate of complications following abortion, ectopic and molar pregnancy and eclampsia rate after adjusting for local tax per capita (p<0.01). Conclusion: These results indicate that poor access to local obstetric care correlate with poor obstetric outcomes (delayed or excessive bleeding, embolism, genital tract or pelvic infection, shock or other complications following abortion and ectopic or molar pregnancy, or eclampsia).

• Economic and Environmental Geology
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• v.43 no.4
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• pp.359-369
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• 2010

This study characterizes aquifer system and hydrogeologic property in the western half of Jeju Island where wells were drilled for regional water supply in three sub-areas (northwestern, western, and southwestern sub-areas). The aquifer system of the northwestern sub-area is largely composed of upper high-permeability layer, upper low-permeability layer, lower high-permeability layer, and lower low-permeability layer. On the other hand, the aquifer systems of the western and southwestern sub-areas are mostly composed of upper low-permeability layer, high-permeability layer, and lower low-permeability layer. Transmissivity and specific capacity decrease in the order of the northwestern, western, and southwestern sub-areas. The relationship between specific capacity and the top surface of tuff is negative with a high correlation coefficient of -0.848, indicating that the tuff acts as the bottom of the aquifer. Groundwater level change due to the 2004 Sumatra earthquake is an average of 23.74 cm in the northwestern sub-area, an average of 9.48 cm in the western sub-area, and none in the southwestern sub-area. Further, it is found that groundwater change due to the earthquake has a positive relationship with transmissivity and specific capacity.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.710-715
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• 2023

Urbanization brings many challenges such as traffic, housing, and environment. To solve these problems, researchers are working on new transportation systems like urban air mobility (UAM). UAM aircraft should fly safely without burdening the existing air traffic system in the early stage of low-density operation. The airspace should also be managed and operated efficiently. Therefore it is important to make urban air traffic predictable by using corridors and collecting data on low-density operations in the early stage. For this purpose various simulations are needed before operation to create scenarios that estimate potential collisions between UAM aircraft and to evaluate the risks of aircraft spacing, loss of separation (LoS), and near mid air collision (NMAC). This paper focuses on identifying the requirements and considerations for setting separation standards for urban air traffic based on the results of studies.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.171-176
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• 2016

Sour gas is natural gas or any other gas containing significant amounts of hydrogen sulfide ($H_2S$). Natural gas is usually considered sour gas if there are more than 5.7 milligrams of $H_2S$ per cubic meter of natural gas, which is equivalent to approximately 4 ppm by volume under standard temperature and pressure We have surveyed on the treatment and removal technology of sour gas, sour gas include a lot of hydrogen sulfide($H_2S$), Carbon dioxide($CO_2$), utane($C_4H_{10}$) and mercaptan($C_nH_{4n-1}SH$) etc. We need high technology for development for these kinds of raw gases and we should specially take care of treating and removal of theses raw gases. Therefor we are going to describe about these kinds of raw gases and about methods how to treat these kinds of gases.