• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.167-178
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• 2003

The design on the Telemetry Ground System for launch of KSLV(Korea Space Launch Vehicle) in the korean Space center has been conducted in this study. For the optimized system design, first of all, the system deployment plan reflecting the topographic and geographic environments of the space center and launch vehicle characteristics has been developed. The RF link budget analysis for the maximum tracking range, requirement for receiving subsystem including antenna subsystem, requirement for data processing subsystem are also analyzed based on the On-Board Telemetry characteristics and launch vehicle parameters. Based on those analysis, telemetry ground system containing tracking/receiving subsystem, recording subsystem and data processing subsystem, timing subsystem, calibration subsystem and monitoring and control subsystem are designed. Futhermore, the analysis for the maximum permissible data latency and communication protocol between each telemetry station and control center are conducted and the entire system is designed so that the major telemetry parameters selected to the best quality are provided in real time to the control center(RCC, RSC) for the launch mission operation.

• Journal of Korean Society of societal Security
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• v.2 no.2
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• pp.49-54
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• 2009

High incident of accidents in construction jobsite became a social problem. According to the International Labour Organization (ILO), more than 60,000 fatal accidents occur each year in construction workplace worldwide. This number of accidents accounts for about 17 percent of all fatal workplace accidents. Especially, accidents from struck-by and falls comprise of over 60 percent of construction fatalities. This paper introduces a prototype of a received signal strength index (RSSI)-based safety monitoring to mitigate the potential accidents caused by falls and struck-by. Correlation between signal strength and noise index is examined to create the distance profile between a transmitter and a receiver. Throughout the distributed sensor nodes attached on potential hazardous objects, the proposed prototype envisions that construction workers with a tracker-tag can identify and monitor their current working environment in construction workplace, and early warning system can reduce the incidents of fatal accident in construction job site.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.7
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• pp.678-684
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• 2009

Many researches on the GNSS integer ambiguity resolution methods for precise positioning and attitude determination applications have been done. However, by the time invariant property of the integer ambiguity, the reuse of integer ambiguity without performing time consuming integer search procedure is possible. In this paper, a new efficient integer ambiguity propagation method is proposed. The initial integer ambiguity can be determined using the famous LAMBDA method and it is propagated with the propagation method. The proposed method can reconfigure the integer ambiguity using the previous epoch's integer ambiguity and new carrier phase measurements under environmental variations such as geometry changes, signal blockage and reacquisition. Experiments with real measurements show the proposed method can determine an integer ambiguity effectively.

• Journal of the Korea Convergence Society
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• v.11 no.6
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• pp.43-49
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• 2020

In spite of the notable advancements of millimeter wave communication technologies, the 60 GHz Wi-Fi is still not widespread yet, mainly due to the high limitation of coverage. Conventionally, it has been hardly possible to support a high data rate with fast beam adaptation while keeping atmospheric beamforming coverage. To solve these challenges in the 60 GHz communication system, holistic system designs are considered. we implemented an enhanced design LDPC decoder enabling 6.72 Gbps coded-throughput with minimal implementation loss, and our proposed phase-tracking algorithm guarantees 3.2 dB performance gain at 1 % PER in the case of 16 QAM modulation and LDPC code-rate 3/4.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.532-539
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• 2018

A position estimation technique is presented for a missile using high-resolution range profiles obtained by three wideband radars. Radar measures a target range using a reflected signal from the surface of a missile. However, it is difficult to obtain the range between the radar and the origin of the missile. For this reason, the interior angle between the moving missile and tracking radar is calculated, and a compensated range between surface of the missile and its origin is added to the tracking range of the radar. Therefore, position estimation of a missile can be achieved by using three total ranges from each radar to the origin of the missile. To verify the position estimation of the missile, electromagnetic numerical analysis software was used to prove the compensated range according to the flight position. Moreover, a wideband radar operating at 500-MHz bandwidth was applied, and its range profile was used for the position estimation of a missile.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.571-577
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• 2010

Driving aircraft requires extremely complicated and detailed information processing. Pilots perform their tasks by selecting the information relevant to them. In this processing, spatial information presented simultaneously through crossmodal link is advantageous over the one provided in singular sensory mode. In this paper, probability to apply providing visual spatial information along with auditory information to enemy tracking system in aircraft navigation is empirically investigated. The result shows that auditory spatial information, which is virtually created through HRTF is advantageous to visual spatial information alone in attention processing. The findings suggest auditory spatial information along with visual one can be presented through crossmodal link by utilizing stereophonic sound such as HRTF. which is available in the existing simple stereo system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1847-1853
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• 2011

Analysis of an indoor propagation channel has conventionally used the ray-tracing method. But, in this paper, we had modelling the channel for three dimensional indoor structure by the finite difference time domain method for three dimensional full wave analysis. An excitation signal of the FDTD method used plane wave. The plane wave was excited using the total field/scattered field method. And absorbing boundary condition used the perfectly matched layer method with 7 layers. An living room for the simulation of indoor channel modeling is surrounded the wall that be composed of the wood, the conductor, the glass and concrete. When there are furniture in the living room or not, it were simulated, respectively. As simulation results, we could identify the fading effect of multipath at indoor propagation environment, calculated mean excess delay and rms delay spread for the receiver design.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1297-1301
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• 2013

This paper analyzes of PD occurrence position through an analysis of the arrival time difference between the GIS partial discharge signal. Because of GIS (Gas Insulated Switchgear) is a facility very important power equipment and as part of the equipment that make up the power system, the stabilization of the power industry, which accounted for 88.5% share of GIS substation in the form of a substation is an important equipment for power supply. In the situation where we are gradually expanding the need for preventive diagnosis in order to improve the efficiency of equipment management and failure prevention for Preventive diagnosis. In this paper as a method for extracting pre-defect of failure of GIS Apply the average value method of calculating the 5 times each using a pulse of the first time of the second pulse (${\Delta}t$) with an oscilloscope generation position PD(Partial Discharge). the results of GIS internal inspection, the partial discharge of the actual the position of the partial discharge was confirmed with an accuracy of about 82% of positions. Arrival time difference in the most effective manner if the partial discharge of GIS internal occurs by applying the averaging method and TOA(Time of arrival) method, the partial discharge occurs you through the measurement and analysis of PD signal occurs was confirmed in the experiment are presented and diagnostic methods location tracking.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.16-24
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• 2006

As a multi-mission GEO satellite, COMS system is being developed jointly by KARI, ETRI, KORDI, KMA, and industries from both abroad and domestic. EADS ASRTIUM is the prime contractor for manufacturing the COMS. ETRI is developing the COMS Ka-band payload and SGCS with the fund from MIC. COMS Satellite Ground Control System (SGCS) will be the only system for monitor and control of the satellite in orbit. In order to fulfill the mission operations of the three payloads and spacecraft bus, COMS SGCS performs telemetry reception and processing, satellite tracking and ranging, command generation and transmission, satellite mission planning, flight dynamics operations, and satellite simulation, By the proper functional allocations, COMS SGCS is divided into five subsystems such as TTC, ROS, MPS, FDS, and CSS. In this paper, functional design of the COMS SGCS is described as five subsystems and the interfaces among the subsystems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.239-244
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• 2018

Both arterial dissection and atherosclerosis are major causes of cerebral infarction and appear to be occlusion or stenosis in magnetic resonance angiography(MRA) and computed tomographic angiography(CTA). But there are differences in treatment because they have different mechanisms. Recently, as high resolution magnetic resonance image(HR-MRI) develops, the image of blood vessel wall can be confirmed non-invasively. Though HR-MRI has become a very useful method for patients with suspected arterial dissection, differential diagnosis of the two diseases has not yet been fully established due to differences in the findings according to stages of arterial dissection and atherosclerosis. We investigated the differences between vertebral artery dissection and atherosclerosis through HR-MRI in two patients and confirmed the diagnosis by CTA follow-up. In addition to the previously established diagnostic criteria, we determined that the long and severe stenosis and recanalization suggest arterial dissection. Characteristics of arterial dissection confirmed by HR-MR and additional studies will be helpful for the treatment.