• 암석학회지
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• 제26권4호
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• pp.373-384
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• 2017

4차 산업 혁명의 시작은 우주산업의 발달을 초래하며 인류가 지구 밖으로 인류의 활동영역을 넓혀가는 첫 계기를 가져다주었다. 아폴로 프로그램이후 달 자원 탐사 및 달 기지 건설이 현실화 되고 있는 것은 미국의 LCROSS (The Lunar Crater Observation and Sensing Satellite)와 LRO (Lunar Reconnaissance Orbiter)의 보다 진보적인 과학적 발전과 중국 창어 미션 등 최근 아시아 국가들이 내놓은 과학적인 새로운 발견이 크게 관여하였다. 달의 극지 자원은 물과 함께 휘발성 물질들이며 현지에서 활용이 요구되므로 인류의 달 기지 건설에 있어서 더욱 중요하다. 헬륨-3는 화석연료가 고갈 될 쯤에는 대체에너지로 활용될 수 있다. 현재 러시아, 유럽과 미국 뿐 만아니라 아시아에서도 달 표면 착륙을 통한 달 탐사와 인류의 향후 기지 건설에 대한 준비는 지속적으로 이어 질 것으로 전망되고 있다. 이러한 시점에서 정확한 달 자원을 이해하고 달 자원 탐사와 활용을 위한 준비는 보다 중요한 현실이라는 점을 고려하여 이 논문은 달 자원 탐사와 달기지에 대하여 고찰하였다.

• International Journal of Advanced Culture Technology
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• 제7권4호
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• pp.313-320
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• 2019

Nowadays, as the availability of tiny, low-cost microcomputer increases at a high level, mobile robots are experiencing remarkable enhancements in hardware design, software performance, and connectivity advancements. In order to control Turtlebot 2, several algorithms have been developed using the Robot Operating System(ROS). However, ROS requires to be run on a high-cost computer which increases the hardware cost and the power consumption to the robot. Therefore, design an algorithm based on low-cost hardware is the most innovative way to reduce the unnecessary costs of the hardware, to increase the performance, and to decrease the power consumed by the computer on the robot. In this paper, we present a path-finding algorithm for TurtleBot 2 based on low-cost hardware. We implemented the algorithm using Raspberry pi, Windows 10 IoT core, and RPLIDAR A2. Firstly, we used Raspberry pi as the alternative to the computer employed to handle ROS and to control the robot. Raspberry pi has the advantages of reducing the hardware cost and the energy consumed by the computer on the robot. Secondly, using RPLIDAR A2 and Windows 10 IoT core which is running on Raspberry pi, we implemented the path-finding algorithm which allows TurtleBot 2 to navigate from the starting point to the destination using the map of the area. In addition, we used C# and Universal Windows Platform to implement the proposed algorithm.

• 문화기술의 융합
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• 제6권4호
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• pp.797-802
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• 2020

지난 몇 년 동안 스마트 폰을 비롯한 다양한 스마트 기기들은 휴대성을 기반으로 사용자의 요구에 의해 지속적으로 성능이 향상 되고 있다. 유비쿼터스 컴퓨팅 (Ubiquitous Computing) 환경과 센서 네트워크 (Sensor network)등의 다양한 망 접속 기술로 인하여 휴대성을 기반으로 하는 단말기들이 다양하게 보급되어 사용되고 있다. 스마트 단말들은 사용 중에 보다 안정적인 동작을 위하여 에너지 모니터링을 세밀하게 할 수 있는 기술이 필요하게 되었다. 소형 경량화 된 스마트 단말기는 다양한 멀티미디어 작업으로 인하여 단말 운용 중에 전원 부족 문제가 발생하게 된다. 이와 같은 상황을 미리 방지하고 안정적인 단말 운용을 위해서 기존에 다양한 추정 하드웨어가 개발 되었다. 그러나 잔량 추정을 하는 방법이나 성능이 비교적 우수하지 못하였다. 본 논문에서는 스마트 단말의 운용 중에 발생 할 수 있는 잔여 잔량 문제를 미리 예측하여 보다 안정적인 운용을 위한 리튬이온 셀의 잔량 추정 방법을 머신러닝에 기초를 두고 연구 하였다. 기존의 하드웨어적인 추정 방법이 아니라 사용 중인 리튬이온 셀의 특성을 머신러닝 기법을 이용한 학습 알고리즘으로 학습 시키고 최적화된 결과를 추정하여 적용 하고자 한다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.262-270
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• 2004

Basic experiments were carried out using the THT-IV low-power Hall thruster to examine the influences of magnetic field shape and strength, and acceleration channel length on thruster performance and to establish guidelines for design of high-performance Hall thrusters. Thrusts were measured with varying magnetic field and channel structure. Exhaust plasma diagnostic measurement was also made to evaluate plume divergent angles and voltage utilization efficiencies. Ion current spatial profiles were measured with a Faraday cup, and ion energy distribution functions were estimated from data with a retarding potential analyzer. The thruster was stably operated with a highest performance under an optimum acceleration channel length of 20 mm and an optimum magnetic field with a maximum strength of about 150 Gauss near the channel exit and with some shape considering ion acceleration directions. Accordingly, an optimum magnetic field and channel structure is considered to exist under an operational condition, related to inner physical phenomena of plasma production, ion acceleration and exhaust plasma feature. A new Hall thruster was designed with basic research data of the THT-IV thruster. With the thruster with many considerations, long stable operations were achieved. In all experiments at 200-400 V with 1.5-3 mg/s, the thrust and the specific impulse ranged from 15 to 70 mN and from 1100 to 2300 see, respectively, in a low electric power range of 300~1300 W. The thrust efficiency reached 55 %. Hence, a large map of the thruster performance was successfully made. The thermal characteristics were also examined with data of both measured and calculated temperatures in the thruster body. Thermally safe conditions were achieved with all input powers.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.848-853
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• 2004

Regarding to the project SUAV (Smart Unmanned Aerial Vehicle) in KARI (Korea Aerospace Research Institute), several engine configurations has been evaluated. However it's not an easy task to collect all the necessary data of each engine for the analysis. Usually, some kind of modeling technique is required in order to determine the unknown data. In the present paper a qualitative method for reverse engineering is proposed, in order to identify some design patterns and relationships between parameters. The method can be used to estimate several parameters that usually are not provided by the manufacturer. The method consists of modeling an existing engine and through a simulation, compare its transient behavior with its operating envelope. In the simulation several parameters such as thermodynamics, performance, safety and mechanics concerning to the definition of operation-envelope, have been discussed qualitatively. With the model, all engine parameters can be estimated with acceptable accuracy, making possible the study of dependencies among different parameters such as power-turbine total inertia, TIT, take-off time and part load, in order to check if the engine transient performance is within the design criteria. For more realistic approach and more detailed design requirements, it will be necessary to enhance the compressor map first, and more realistic estimated values must be taken into account for intake-loss, bleed-air and auxiliary power extraction. The relative importance of these “unknown” parameters must be evaluated using sensitivity analysis in the future evaluation. Moreover, fluid dynamics, thermal analysis and stress analysis necessary for the resulting life assessment of en engine, will not be addressed here but in a future paper. With the methodology presented in the paper was possible to infer the relationships between operation-envelope and engine parameters.

• 지구물리와물리탐사
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• 제14권3호
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• pp.203-213
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• 2011

시간경과(time-lapse) 탄성파 저류층 모니터링은 생산 저류층에서 유체 흐름의 변화를 영상화 하기 위해, 동일한 탐사 지역에서 시간 차를 두고 탄성파 탐사를 여러 번 수행하여 자료를 획득, 처리, 분석하는 과정으로 요약할 수 있다. 생산 중인 광구에서는 가스 및 오일을 생산하면서 저류층 내 유체의 변화를 모니터링하여, 가채 자원량 및 생산에 필요한 변수 값의 변화를 확인하는 필수도구로 사용된다. 또한 특정 생산정의 최적 회수율 평가, 회수율을 증대시키기 위한 생산기법, 그리고 이를 위한 변수 선정에도 적용될 수 있다. 최근에는 이산화탄소($CO_2$) 지중저장에도 모니터링 기법을 적용하여 저장된 이산화탄소의 변화 양상을 분석하는 사례가 보고되고 있다. 국내 업체들이 최근 외국 사이트에서의 석유광구 지분 참여 등 투자를 늘리고 있는 상황에서 정확한 투자 가능성 진단과 기술 자체의 고부가가치를 생각할 때, 시간경과 탄성파 저류층 모니터링은 향후 그 중요성이 더욱 증대될 연구 분야이다. 이 논문에서는 시간경과 탄성파 저류층 모니터링에 대한 이해를 돕기 위해 시간경과 탄성파 탐사의 개념, 설계, 방법, 자료처리 해석 등에 대하여 간략히 소개한다.

• 융합보안논문지
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• 제12권3호
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• pp.75-83
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• 2012

높은 네트워크 대역폭과 고품질을 요구하는 고에너지 물리, 기상 기후 등과 같은 특정 연구 그룹간의 논리 네트워크를 구축하여, 일종의 특정 그룹별 사설 네트워크 구축과 운용이 최근 많이 요구되고 있다. 지금까지 국내에서는 KREONET과 같은 국가연구망이 중심이 되어 이러한 대용량 사설 네트워크 서비스를 제공하고 있으나 이러한 사설 네트워크에 대한 체계적이고 표준화된 구축 및 관리 방법이 없어 이에 대한 체계적인 연구가 시급한 실정이다. 이를 위해 본 논문은 L2 기반에서 다양한 그룹별 논리 네트워크를 구성하는 핵심 서비스 요소와 표준 프로토콜을 제시하고, 구성된 논리 네트워크 정보를 관리 모니터링 할 수 있는 시스템 구조를 제시하였다. 또한 본 논문은 네트워크 인프라 자원과 관련된 망의 운영정보, 구성정보, 성능정보, 장애정보 등에 대한 정보를 통합적으로 관리할 수 있는 표준화된 명세시스템 구조를 제시하였다.

• Journal of Ecology and Environment
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• 제29권4호
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• pp.405-410
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• 2006

Landscape changes for 20 years between 1981 and 2001 in the Wangsuk stream basin located on the central Korea were investigated on the basis of physiognomic vegetation map made from the aerial photograph interpretation and field check. Changes of landscape structure were noticeable in agricultural field and forest landscape elements. Changes in the agricultural fields due to transformation of agricultural pattern into the institutional agriculture dominated landscape change, although urbanization also contributed to such change. The former change due to change of food production structure originated from socio-economic development during this period and the latter to the overpopulation of Seoul. As energy sources for heating and cooking, fertilizer, and fodder for livestock transform from plant materials to fossil fuel, manufactured one, and grain, succession of forest escaped from direct human disturbance dominated change of landscape structure in forested land. Differently from the positive landscape change in the upper area, change in the lower area deteriorated landscape quality by increasing artificial land. It was estimated that such landscape deterioration in the Wangsuk stream basin would influence water quality of the stream. In order to realize sustainable land-use against such environmental degradation, systematic environmental management based on landscape ecological perspective such as "an eco-plan for creating riparian vegetation belt," which is under preparation by Ministry of Environment, was recommended.

• 전기학회논문지
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• 제64권5호
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• pp.667-679
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• 2015

The bearer of the power sector's ETS compliance cost is power consumer for the following reasons. Firstly, power companies are constrained in establishing appropriate strategies to comply with ETS regulations due to the structural differences between the domestic power market and emission trading system. In other words, because power companies do not have a right to determine price and production of electricity, they have to compete with other companies under disadvantaged conditions in the emission trading market. Secondly, because ETS compliance cost is part of power production costs as it is also clearly written in the national greenhouse gas reduction road-map and the second energy supply plan, the cost should be included in power price following the power market operation rule. Thirdly, the most effective method to reduce carbon emissions in power sector is to reduce power demand, which is efficiently achieved through raising power price to a realistic level. Low power price in Korea is the major cause of rising power demand which is also the major cause of rising GHG emission. Therefore, power sector's ETS compliance cost should be included in power price to encourage power consumers' actions on reducing power consumption. Fourthly, when externality cost occurs in the process of delivering public services, usually beneficiary pay principle is applied to identify the cost bearer. Since electricity is one representative public good, the bearer of power sector's ETS compliance cost is power consumer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권5호
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• pp.2366-2395
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• 2018

Multi-view super-resolution (MVSR) refers to the process of reconstructing a high-resolution (HR) image from a set of low-resolution (LR) images captured from different viewpoints typically by different cameras. These multi-view images are usually obtained by a camera array. In our previous work [1], we super-resolved multi-view LR images via image fusion (IF) and blind deblurring (BD). In this paper, we present a new MVSR method that jointly realizes IF and BD based on an integrated energy function optimization. First, we reformulate the MVSR problem into a multi-channel blind deblurring (MCBD) problem which is easier to be solved than the former. Then the depth map of the desired HR image is calculated. Finally, we solve the MCBD problem, in which the optimization problems with respect to the desired HR image and with respect to the unknown blur are efficiently addressed by the alternating direction method of multipliers (ADMM). Experiments on the Multi-view Image Database of the University of Tsukuba and images captured by our own camera array system demonstrate the effectiveness of the proposed method.