• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.283-287
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• 2011

Science and Technology Satellite-3 (STSAT-3) is a 150 kg class micro satellite based with the national space program. The STSAT-3 system consists of a space segment, ground segment, launch service segment, and various external interfaces including additional ground stations to support launch and early operation phases. The major ground segment is the ground station at the Satellite Technology Research Center, Korea Advanced Institute of Science and Technology site. The ground station provides the capability to monitor and control STSAT-3, conduct STSAT-3 mission planning, and receive, process, and distribute STSAT-3 payload data to satisfy the overall missions of STSAT-3. The ground station consists of the mission control element and the data receiving element. This ground station is designed with the concept of low cost and high efficiency. In this paper, the requirements and design of the ground station that has been developed are examined.

• 항공우주기술
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• 제11권1호
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• pp.111-117
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• 2012

애자일(Agile)은 논증 가능한 구체적인 목표(사람, 협조, 반응성, 작동하는 소프트웨어)를 위해서 창시된 소프트웨어 개발 방법론으로, 소프트웨어 엔지니어링뿐만 아니라 여러 전문 분야에 적용되고 있다. ESA (European Space Agency)의 경우 애자일의 대표적인 방법인 스크럼 (Scrum)을 중심으로 지상국 분야의 소프트웨어 개발에 애자일을 적용하였다. 본 논문에서는 애자일 기술의 동향을 살펴보고, 이를 도입한 ESA 지상국 소프트웨어 개발의 최근 사례를 분석한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.757-762
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• 2007

The lining segment which is the main structure of the shield tunnel consists of joints, not continua. Past international and domestic design data have been commonly used for design practices without specific verification about the structural analysis model, design load, and affection of the soil constant of the lining segment. In this study, the propriety is estimated through the comparison between analytical solution and numerical solution for segment analysis and design models of the shield tunnel which is being used internationally and domestically. As a result, the full. circumferential beam jointed spring model (1R-S0) is suggested by considering aspects of convenient use, application to field condition, and accuracy of analysis result. With suggested model, the parameter analysis was conducted for joint stiffness, ground rigidity, joint distribution, and joint number.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.228-228
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• 2002

The DLS(Data Link System) is located in the PDTS(Payload Data Transmission Subsystem) of KOMPSAT-II, and its main function is to provide communication link with Ground Segment as a space segment. DLS receive the data of MSC, OBC from DCSU(Data Compression Storage Unit) and transmit to the Ground Station by X-Band RF link. DLS is consist of CCU(Channel Coding Unit), QTX(QPSK Transmitter, ASU(Antenna Switch Unit) CCU makes a packet for communication after several kind of data processing such like Ciphering, RS Coding. QTX transmit PDTS data by OQPSK. Modulation. ASU is the unit for reliability of antenna switching. So, DLS's function is consists of ciphering, RS coding, CCSDS packetizing, randomizing, modulation and switching to antenna. These DLS's functions are controlled by PMU(Payload Management Unit). All commands to DLS are sent by PMU and all telemetries of DLS are sent to the PMU. The PMU receives commands from OBC and sends telemetries to the OBC. The OBC communicates with Ground Station by S-Band RF link. This paper presents the on-orbit DLS operation concept through the ground segment.

• Structural Engineering and Mechanics
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• 제71권3호
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• pp.305-315
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• 2019

Extremely long-span transmission tower-line system is an indispensable portion of an electricity transmission system, and its failures or collapse can impact on the entire electricity grid, affect the modern life, and cause great economic losses. It is therefore imperative to investigate the failure and safety of the transmission tower subjected to ground motions. In the present study, a detailed finite element (FE) model of a representative extremely long-span transmission tower-line system is established. A segmental damage indicator (SDI) is proposed to quantitatively assess the damage level of each segment of the transmission tower under earthquakes. Additionally, parametric studies are conducted to investigate the influence of different ground motions and incident angles on the ultimate capacity and weakest segment of the transmission tower. Finally, the collapse fragility curve in terms of the maximum SDI value and PGA is plotted for the exampled transmission tower. The results show that the proposed SDI can quantitatively assess the damage level of the segments, and thus determine the ultimate capacity and weakest segment of the transmission tower. Moreover, the different ground motions and incident angles have a significant influence on the SDI values of the transmission tower, and the collapse fragility curve is utilized to evaluate the collapse resistant capacity of the transmission tower subjected to ground motions.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.544-547
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• 2007

Because data processing systems in recent years are more complicated, main function of the data processing is divided as several sub-functions which are implemented and verified in each subsystem of the data processing system. For the verification of data processing system, many interface tests among subsystems are required and also a lot of simulation systems are demanded. This paper proposes CTHS (Common Test Harness System) for satellite ground segment development which has all of functions for interface test of the data processing system in one PC. Main functions of the CTHS software are data interface, system log generation, and system information display. For the interface test of the data processing system, all of actions of the CTHS are executed by a pre-defined operation scenario which is written by purpose of the data processing system test.

• Geomechanics and Engineering
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• 제29권4호
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• pp.471-486
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• 2022

The effect of segmental joints is one of main importance for the segmental lining design when tunnels are excavated by a mechanized process. In this paper, segmental tunnel linings are analyzed by two numerical methods, namely the Beam-Spring Method (BSM) and the Solid-Interface Method (SIM). For this purpose, the Tehran Subway Line 6 Tunnel is considered to be the reference case. Comprehensive 2D numerical simulations are performed considering the soil's calibrated plastic hardening model (PH). Also, an advanced 3D numerical model was used to obtain the stress relaxation value. The SIM numerical model is conducted to calculate the average rotational stiffness of the longitudinal joints considering the joints bending moment distribution and joints openings. Then, based on the BSM, a sensitivity analysis was performed to investigate the influence of the ground rigidity, depth to diameter ratios, slippage between the segment and ground, segment thickness, number of segments and pattern of joints. The findings indicate that when the longitudinal joints are flexible, the soil-segment interaction effect is significant. The joint rotational stiffness effect becomes remarkable with increasing the segment thickness, segment number, and tunnel depth. The pattern of longitudinal joints, in addition to the joint stiffness ratio and number of segments, also depends on the placement of longitudinal joints of the key segment in the tunnel crown (similar to patterns B and B').

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권3호
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• pp.171-176
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• 2017

최근, 효율적인 위성자료처리시스템의 개발을 위해 고성능 컴퓨팅, 클라우스 서비스, 데브옵스 방법론 등의 정보기술(information technology; IT)을 활용하는 연구가 활발히 진행되고 있다. 해양의 장단기 변화를 관측하여 해양재해 재난 예측 및 어장환경 관리를 지원하기 위해 정지궤도해양관측위성-II(Geostationary Ocean Color Imager II; GOCI-II)이 2019년 3월 발사될 예정이며, 자료 수신/처리/저장/배포를 위한 지상시스템(GOCI-II Ground Segment; G2GS)이 해양위성센터에서 설계되고 있다. G2GS는 자료수신(data acquisition subsystem; DAS), 자료보정(data correction subsystem; DCS), 정밀보정(precision correction subsystem; PCS), 자료처리(ocean data processing subsystem; ODPS), 자료관리(data management subsystem; DMS), 운영및품질관리(operation & quality management subsystem ; OQMS) 등 6개의 서브시스템으로 구성되어 있다. G2GS를 이용하여 GOCI-II로부터 생산된 해양 분석 자료를 유관기관 및 일반 사용자에게 실시간으로 제공할 수 있을 것이라 기대하고 있다.

• 한국터널지하공간학회 논문집
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• 제13권3호
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• pp.233-242
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• 2011

본 연구에서는 쉴드터널에 사용되는 세그먼트의 성능향상과 경제성향상을 위하여 고로슬래그 미분말을 혼합한 고강도 콘크리트에 대한 기초 연구를 실시하였다. 특히, 설계강도가 60 MPa 세그먼트용 콘크리트에 대해서 고로슬래그 미분말의 최적 치환율과 최적의 증기양생 조건을 도출하고자 하였다. 이상의 결과로부터, 고로슬래그 치환율 50%와 단위수량 125 kg/$m^3$ 일 경우가 성능과 경제적인 측면에서 가장 적합한 배합조건으로 나타났다. 또한 표준양생 조건과 비교할 때 증가양생에 의하여 약 110~442%의 강도증진 효과를 기대할 수 있는 것으로 확인되었다.

• Geomechanics and Engineering
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• 제29권3호
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• pp.229-236
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• 2022

In this study, a model experiment and field experiment was conducted to introduce the optimal tensile force when constructing a non-open cut tunnel according to the ground conditions of sandy soil. CMR (Concrete Modular Roof) method is economical because of the high precision and excellent durability, and corrosion resistance, and the inserted parts can be used as the main structure of a tunnel. In addition the CMR method has a stable advantage in interconnection because the concrete beam is press-fitted compared to the NTR (New Tubular Roof) method, and the need for quality control can be minimized. The ground conditions were corrected by adjusting the relative density of sandy soil during the construction of non-open cut tunnels, and after introducing various tensile forces, the surface settlement according to excavation was measured, and the optimal tensile force was derived. As a result of the experiment, the amount of settlement according to the relative density was found to be minor. Furthermore, analysis of each tensile force based on loose ground conditions resulted in an average decrease of approximately 22% in maximum settlement when the force was increased by 0.8 kN per segment. Considering these results, it is indicated that more than 2.0 kN tensile force per segment is recommended for settlement of the upper ground.