• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.997-1010
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• 2021

This study collected and analyzed flight data of SpaceX's Falcon 9 launch vehicle. All missions were classified by orbital types, such as Polar, SSO, ISS, LEO and GTO missions. In characteristic maneuvers of main engine cutoff, boostback, reentry and landing burn at each stage of 1st stage launch vehicle, changes of the physical parameters like speed, altitude, dynamic pressure and acceleration were investigated. The guidelines derived from detailed maneuver analysis were suggested, which can be used as design and evaluation references for developing reusable launch vehicle.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.215-220
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• 2023

Network technology used as a physical interface to retrieve, store, and exchange data is leading the era of data capitalism in the 21st century. The capacity of network technology dominates almost all communication in everyday life, and makes social understanding and experiences in the physical world visible in cyberspace. The movements of human bodies and objects in cyberspace are placed in a social context. This paper paid attention to these phenomena and examined the cases of activism that raised real problems through cyberspace. In particular, the focus of the study is the digital activism of the Electronic Disturbance Theater, which combines critical art and thinking for democracy with the realm of information and demonstrates aesthetic imagination. The first chapter of the main body briefly outlines the meaning activism as a social movement in cyberspace. The second chapter looks back on the alternatives of <FloodNet>, which represents the early activism performance of EDT. And then in the last chapter, the poetic significance of the <Transborder Immigrant Tool> is analyzed. Through this process, this paper demonstrates that the activism performance of the EDT is a critical aesthetics that encourages imagination for alternatives. It also argues that Electronic Disturbance Theater has contemporary value as an avant-garde art that actively utilizes the medium of network technology and integrates performance art and politics.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.332-333
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• 2022

Recently, SpaceX, private enterprise dealing in space development company, has reported a plan for launching of 42,000 low earth orbit satellites until 2031 through Starlink Business, and launched 900 satellites until now. Concretely, it plans tp operate Ku/Ka band satellite, and launch 7,518 of V band satellites for broadband communication. Therefore, we can utilize wireless communication in an ocean, and various solutions through the low earth orbit satellites. This paper deals in a realization of wireless control system employing FPGA (Field Programmable Gate Array) for vessel applications.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.390-391
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• 2022

Recently, SpaceX, private enterprise dealing in space development company, has reported a plan for launching of low earth orbit satellites via Starlink Business, and launched 900 satellites until now. Concretely, it plans tp operate Ku/Ka band satellite, and launch 7,518 of V band satellites for broadband communication. Therefore, wireless communication service for ship will be provided, and various solutions will be offered through the low earth orbit satellites. In this work, we investigated RF characteristics of coplanar waveguide employing periodic 3D coupling structures, and examined its potential for a development of marine radio communication FISoC (fully-integrated system on chip) semiconductor device.

• Electronics and Telecommunications Trends
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• v.30 no.4
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• pp.162-173
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• 2015

약 20년 전 세상의 이목을 끌었다가 무너진 꿈으로 남아있는 위성벤처 1.0. 즉 텔레데식, 이리디움 등으로 대표되던 대규모 저궤도 위성군(Big LEO) 통신시스템이 다시 추진되고 있다. 이른바 위성벤처 2.0으로 불리우는 스페이스엑스(Space Exploration Technologies: SpaceX). 원웹(OneWeb), 리오셋(Leosat) 등의 저궤도 위성군 통신시스템의 경쟁적 재등장이다. 이 배경에는 인터넷 업체인 구글(Google)과 페이스북(Facebook)이 관련되어 있다. 이미 과거의 경험이 있는 상황이기 때문에 성공가능성에 대한 기대가 상당히 크지만 회의론도 만만치 않다. 이들의 등장배경과 각 시스템의 기술적 제안, 비지니스 모델, 그리고 네트워크 구축 및 운용경비 절감을 위한 각각의 전략적 접근에 대해서 간략히 알아본다. 기존 이리디움이나 글로벌스타도 1세대 위성수명이 다하여 이제 2세대 위성군으로 업그레이드된 상태이라 신구 시스템 간의 차별적 경쟁도 이제 피할 수 없게 되었다. 신규제안 시스템의 성공적 안착을 위한 고려사항과 이러한 흐름에 대한 우리나라의 대응도 살펴보았다.

• Journal of the Korean Institute of Landscape Architecture
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• v.13 no.2
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• pp.99-114
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• 1985

^x Open space has become the subject o\ulcorner remarkable, new interest ; and many studies have been done recently. In urban pattern, the significance of open space is not its quantity but how it is arranged. The end of this article is to set up a plan for the open space system for Kyongiu city. This paper has three parts : first, a brief discussion of the concept and function of open space ; secondly, a review of open space system ; and finally, a case study of Kyongju City. Especially, this study is focuced on the methodology in conserving and using prototype plan for historic and cultural environment. The result of this study may be summed up as follows : 1) The open space network for kyongju city can be planned out as a belt and ripple pattern. 2) The linear element of open space must play an important role in connecting each element with the whole open space system. 3 ) The Hwangseong pork can be the focal element of the open space system.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.267-276
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• 2003

Many countries have established eBook standards adequate to their environments. In USA, OEB PS is announced for distribution and display of eBooks, in Japan, JepaX is announced for storage and exchange, and in Korea, EBKS is made for clear exchange of eBook contents. These diverse objectives lead to different content structures. These variety of content structure will cause a problem in exchanging them. To correctly exchange eBook contents, the content structure should be considered. So, In this paper, we study conversion methods of standard eBooks contents based on Korean eBook standard, with contemplating content structure. To convert contents properly, the mapping relations should be clearly defined. For this, we consider standard's structure and extension mechanisms, and use path notations and namespaces for precise description. Moreover, through analysis of each mapping relationships, we classify conversion cases into automatic, semi-automatic, and manual conversions. Finally we write up conversion scripts and experiment with them.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.233-254
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• 2017

The purpose of this study is to analyze the main factors influencing the severity of traffic accidents and to visualize spatiotemporal characteristics of traffic accidents in Seoul. To do this, we collected the traffic accident data that occurred in Seoul for four years from 2012 to 2015, and classified as slight, serious, and death traffic accidents according to the severity of traffic accidents. The analysis of spatiotemporal characteristics of traffic accidents was performed by kernel density analysis, hotspot analysis, space time cube analysis, and Emerging HotSpot Analysis. The factors affecting the severity of traffic accidents were analyzed using decision tree model. The results show that traffic accidents in Seoul are more frequent in suburbs than in central areas. Especially, traffic accidents concentrated in some commercial and entertainment areas in Seocho and Gangnam, and the traffic accidents were more and more intense over time. In the case of death traffic accidents, there were statistically significant hotspot areas in Yeongdeungpo-gu, Guro-gu, Jongno-gu, Jung-gu and Seongbuk. However, hotspots of death traffic accidents by time zone resulted in different patterns. In terms of traffic accident severity, the type of accident is the most important factor. The type of the road, the type of the vehicle, the time of the traffic accident, and the type of the violation of the regulations were ranked in order of importance. Regarding decision rules that cause serious traffic accidents, in case of van or truck, there is a high probability that a serious traffic accident will occur at a place where the width of the road is wide and the vehicle speed is high. In case of bicycle, car, motorcycle or the others there is a high probability that a serious traffic accident will occur under the same circumstances in the dawn time.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.121-146
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• 2018

In traditional international law, a state was internationally responsible only for its activities. With the diversification of the subjects of international law and with the expansion of state's activities, however, bearing international responsibility by the state for its nationals or private enterprises has been recognised in international case law and states practices. Also, this was codified in 2001 by International Law Commission, finishing Draft articles on Responsibility of States for Internationally Wrongful Acts. Yet, international responsibility of state for private entities carrying out space activities including launching of satellites and space launch vehicles has been dealt with as an exception from state responsibility in general international law. As we have seen the successful launching of 'Falcon Heavy' by SpaceX which is an american private entity, the private activities in outer space are expanding to even as far as deep space such as Mars. In other words, the scope of the private activities is too enormous to deal with the activities, irrespective of general theories on state responsibility in international law. Therefore, it will be significant to see the constituent elements of state responsibility for private activities in outer space from the point of general international law, without prejudice to provisions related to international space law.