• Journal of Conservation Science
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• v.23
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• pp.73-80
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• 2008

This article aims to turn out the authentication of archaeological materials by using the paleodose measurement to fine sand-size quartz grains obtained by micro sampling technique. We firstly revealed the validity of micro sampling technique from the paleodoses of two bricks related to Muryong Royal Tomb of Baekje Kingdom. For the purpose of authentication test, four archaeological materials were selected, because they have been insisted that they were manufactured in Goguryeo Kingdom era. After obtaining very few quartz grains by micro sampling technique, each paleodose was evaluated by using SGR (single grain regenerative dose method). All values were very low below 0.2Gy and the reliability was found from those values by using SAR (single aliquot regenerative dose method). Considering the archaeological situation and the general paleodose, the burial time for 1,000 years generally corresponds to about 3.5Gy in Korea, it is concluded that these archaeological materials are all modern counterfeits.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.373-376
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• 2009

A full rig combustor test and altitude ignition test were carried out for radial-annular combustor of micro turbojet engine. 11.2% total pressure loss and 99.85% of combustion efficiency were measured at design point of engine under sea level standard condition and $2{\sim}6$ of air excess ratio for ignition envelope was achieved on engine starting regime. Finally, A 30,000 ft high altitude ignition test was also performed and finally we found out that the developed radial-annular combustor is appropriate to micro turbojet engine.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.644-653
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• 2013

In this paper, a formulation for obliquely incident electromagnetic wave has been presented for an analysis of highpower electromagnetic pulse penetration into multilayered dispersive media. Based on generalized models of measured dielectric constants and propagation channels reflecting the Earth's general features, the propagation phenomenon of the obliquely incident early-time(E1) high altitude electromagnetic pulse(HEMP) is analyzed. In addition, the polarization and critical angle are also considered. It is found that the total reflection occurs at an incident angle of about 38 degrees at the soil-rock interface, and that the parallel-polarized E1 HEMP penetrates better than the perpendicular-polarized one. The peak level of the penetrating electric field is found to be 5.6 kV/m at normal incidence, regardless of the type of polarization, and E1 HEMP is greatly reduced near the critical angle. Moreover, the penetrating E1 HEMP is analyzed as a variation of moisture content and depth of materials, resulting E1 HEMP could be useful in determining the levels of shielding required for buried facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.100-106
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• 2019

Ground and high altitude simulated combustion experiments were conducted using a liquid rocket engine with hydrogen peroxide and kerosene as the propellant. A ground and high altitude simulated combustion test facility was constructed by installing a high altitude model diffuser and TMS (Thrust Measuring System) on a vertical combustion test bench. The thrust characteristics according to altitude were investigated using the combustion test equipment. The diffuser was designed on a 1:4.8 scale to verify the characteristics of the high diffusing diffuser and starting pressure. The cold flow tests were conducted using nitrogen gas, and the performance characteristics and starting characteristics of the scale down diffuser were verified. A diffuser and TMS were installed on the vertical combustion test bench, and the thrust correction equations for the system resistance were derived. The thrust correction equations were derived from the step test and vacuum step test before the actual hot firing test. Nozzles with an operating altitude of 10km were designed. Hot firing tests were conducted to analyze the thrust characteristics according to the operating altitude changes. The actual thrust was calculated using each correction equation with the thrust value measured by the TMS.

• Information and Communications Magazine
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• v.25 no.9
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• pp.57-63
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• 2008

본고에서는 위성 통신의 장점과 지상 통신의 장점을 갖춘 고고도 통신 (HAPS : High Altitude Platform Station) 기술에 대한 국내외 개발 동향을 알아본다. 이를 위하여 유럽 및 일본 등 국외 개발기관에서의 플랫폼 및 통신시스템 기술개발동향과 국제표준기구인 ITU-R(International Telecommunication Union - Radiocommunication sector)에서의 HAPS 운용을 위한 관련 결의서 및 권고서 개발 등의 표준 개발 동향을 중심으로 분석한다.

• Korean Journal of Heritage: History & Science
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• v.41 no.1
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• pp.21-33
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• 2008

In this study, the researcher examined archaeomagnetic secular variation of Chungcheong Region through measured data of archaeomagnet obtained from 34 relics, which discovered in the baked earth from varied historic sites within the region. Furthermore, the researcher closely reviewed regional differences of geomagnetic field in the domestic territory. Reviewing the comparison between the measured data of archaeomagnet in Chungcheong Region and the archaeomagnetic secular variation of Japan, which has difference in distance, it reveals a noticeable change in declination by tilting more than 10 degree toward East in the year of about A.D. 300, although the feature of whole variation is quite similar. In other period of times, it was confirmed that the regional differences of geomagnetic field in which the magnetic dip became deeper to some degree, and the declination was tilted westward a little bit. Such patterns do not differ significantly from the pattern of entire archaeomagnetic secular variation of our country, and even in the direct comparison to the data of Chungcheong Region, the distinct regional difference in both periods before and after Christian era was not confirmed. The fact may become clearer that, when the volume of the measured data of archaeomagnet increases further, and when more data connected with varied time period are filled, the problem such as deviation of the measurement period of archaeomagnet caused by the regional difference of geomagnetic field would not be worrisome issue, especially in Korean territory, judging from the measured data of archaeomagnet of historic relics in Chungcheong Region. Besides, as great efforts are being exerted in order to get the most reliable measured data as much as possible in taking both samples and measurement, it is thought that there would be no problem not only in the issue of deviation of the measurement period involving with the measured data of archeomagnet, but also in the aspect of reliability of data.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.5-34
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• 2007

Archaeological Heritage is material testimony of national and regional history, and it is one of the tourist's attractions. So it has very important meaning and identical value for a local residents. Public concern on the heritage site elevate higher day by day. They are willing to use it for a multiful purpose, cultural, educational, and even commercial one. But Archaeological Heritage is fragile, and visitors can impact negatively for protection and management of the authenticity on the heritage site. In this research I try to compare legal and administrative measure for the protection, management, and culturalization of Archaeological Heritage in many countries. And I suppose sustainable and practical strategies for keeping integrity of heritage.

• Korean Journal of Heritage: History & Science
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• v.56 no.2
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• pp.28-45
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• 2023

Although we have entered the era of digital transformation, there is currently no system that efficiently collects, manages, integrates, and services a large number of archaeological digital source materials produced as a result of cultural relics research, i.e., an intelligent integrated management and service platform for archaeological academic information. In this regard, the need to build a digital dictionary of Korean archaeology was confirmed by examining the problem of the Digital Encyclopedia of Korean Archaeology, which is currently available in PDF format on the web, the current status of the publication and use of the Dictionary of Korean Archaeology, and the cases of building digital platforms at home and abroad. Therefore, this paper aims to suggest a general direction for creating a digital encyclopedia of Korean archaeology based on the Dictionary of Korean Archaeology, which includes quality knowledge information, to reconsider the accessibility of archaeological data in conformity with data access limitations. The application of the series Dictionary of Korean Archaeology, published since 2001, and the necessity for digital transformation were examined, as well as the application of data from the archaeological data archiving platforms of Europe, the USA, Japan, and cases of establishing platforms corresponding to specialized encyclopedias from Korea. Based on these, a three-step implementation plan and detailed projects were suggested to create the Digital Encyclopedia of Korean Archaeology. Through this, we proposed the design of metadata for computerized records and the expansion to semantic (meaning-based) data that gives and shows the relationship information between the produced metadata as the implementation tasks to build the Digital Dictionary of Korean Archaeology. It is hoped that such research will help create an integrated intelligent management and service platform for archaeology, raise awareness, and provide a better understanding of Korean archaeology to the general public.

• Journal of Aerospace System Engineering
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• v.11 no.5
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• pp.56-64
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• 2017

A high altitude long endurance aircraft which carries out missions of environmental research communication relay or ground surveillance, should have the capacity to cruise in the stratosphere at a relatively low speed for a long dwell time without the necessity of refueling. When one considers the propulsion system for such an aircraft, a reciprocating engine with a serial turbo-charger system to boost rarefied ambient air up to sea level condition, would represent an good, informed and practical choice regardless of the cruising altitude of the aircraft. In this paper, high altitude long endurance aircraft developed by overseas research groups and research trends, regarding multi-stage turbocharger systems, are introduced.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.35-41
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• 2018

Unmanned Aerial Vehicles (UAV) have been used for various purposes in multiple fields, such as observation, communication relaying, and information acquisition. Nowadays, UAVs must have high performance in order to acquire more precise information in larger amounts than is now possible while performing for long periods. At present, domestically, a high-altitude long-endurance UAV (HALE UAV) for long-term flight in the stratosphere has been developed in order to replace some functions of the satellite. In this study, as a part of structural soundness evaluation of the aircraft structure developed for the HALE UAV, the structural soundness of the fasteners of the fuselage and tail is evaluated by calculating the margin of safety(M.S). The result confirms the validity of the design of the fasteners in the aircraft structure of the UAV.