• 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 Astronomy and Space Sciences
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• v.14 no.2
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• pp.312-319
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• 1997

The magnetometer is one of the most important payloads for scientific satellite to monitor the near-earth space environment. The electromagnetic variations of the space environment can be observed with the electric and magnetic field measurements. In practice, it is well known that the measurement of magnetic fields needs less technical complexities than that of electric fields in space. Therefore the magnetometer has long been recognized as one of the basic payloads for the scientific satellites. In this paper, we discuss the scientific fluxgate magnetometer which will be on board the KITSAT-3. The main circuit design of the present magnetometer is based on that of KITSAT-1 and -2 but its facilities have been re-designed to improve the resolution to about 5nT for scientific purpose. The calibration and noise level test of this circuit have been performed at the laboratory of the Tierra Tecnica company in Japan.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.55-61
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• 2023

Although corporate punishment-related systems are being implemented in several countries, such as South Korea's Serious Accidents Punishment Act (SAPA), related research has mainly focused on legal issues. This study aimed to compare and analyze the SAPA and Singapore's Workplace Safety and Health Act (WSHA) and Code of Practice on Chief Executives' and Board of Directors' Workplace Safety and Health Duties (WSHD). In addition, it was attempted to draw implications to enhance the effectiveness of the CEO's safety and health duties. For this study, a comparative analysis was conducted in 3 steps. In step 1, similar overseas systems were investigated. In step 2, the system contents were classified into four viewpoints (DUTY, RESOURCE, Other factors, and Main contents), and comparison items were derived from each viewpoint. In step 3, the viewpoints were compared, and implications were derived. The following three implications were derived through comparative analyses. 1) In WSHD, additional explanation and calibration of measures clarify the CEO's role, and 2) It is easy to use for the CEO's duties by providing the resources directly. 3) Penalties for violating the proposed duties are entrusted to the existing higher-level laws. Considering this, providing detailed content and related information for the CEO would possibly improve the SAPA to fulfill his/her duties through announcements from related organizations in the future.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.4
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• pp.207-213
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• 2018

This paper investigates applicability of Microsoft $Kinect^{(R)}$, RGB-depth camera, to implement a 3D image and spatial information for sensing a target. The relationship between the image of the Kinect camera and the pixel coordinate system is formulated. The calibration of the camera provides the depth and RGB information of the target. The intrinsic parameters are calculated through a checker board experiment and focal length, principal point, and distortion coefficient are obtained. The extrinsic parameters regarding the relationship between the two Kinect cameras consist of rotational matrix and translational vector. The spatial images of 2D projection space are converted to a 3D images, resulting on spatial information on the basis of the depth and RGB information. The measurement is verified through comparison with the length and location of the 2D images of the target structure.

• Journal of Platform Technology
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• v.9 no.1
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• pp.32-39
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• 2021

Existing environmental measuring devices mainly focus on electromagnetic wave and eco-friendly product certification and durability test, and sensor reliability verification and verification of measurement data are conducted mainly through sensor performance evaluation through type approval and registration, acceptance test, initial calibration, and periodic test. This platform has established an ICT-based environmental monitoring sensor reliability verification system that supports not only performance evaluation for each target sensor, but also a verification system for sensor data reliability. A sensor board to collect sensor data for environmental information was produced, and a sensor and data reliability evaluation and verification service system was standardized. In addition, to evaluate and verify the reliability of sensor data based on ICT, a sensor data platform monitoring prototype using LoRa communication was produced, and the test was conducted in smart cities. To analyze the data received through the system, an optimization algorithm was developed using machine learning. Through this, a sensor big data analysis system is established for reliability verification, and the foundation for an integrated evaluation and verification system is provide.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.195-203
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• 2017

A 2U cube satellite called SNUGLITE has been developed by GNSS Research Laboratory in Seoul National University. Its main mission is to perform actual operation by mounting dual-frequency global positioning system (GPS) receivers. Its scientific mission aims to observe space environments and collect data. It is essential for a cube satellite to control an Earth-oriented attitude for reliable and successful data transmission and reception. To this end, an attitude estimation and control algorithm, Attitude Determination and Control System (ADCS), has been implemented in the on-board computer (OBC) processor in real time. In this paper, the Extended Kalman Filter (EKF) was employed as the attitude estimation algorithm. For the attitude control technique, the Linear Quadratic Gaussian (LQG) was utilized. The algorithm was verified through the processor in the loop simulation (PILS) procedure. To validate the ADCS algorithm in the ground, the experimental verification via a single axis Hardware-in-the-loop simulation (HILS) was used due to the simplicity and cost effectiveness, rather than using the 3-axis HILS verification (Schwartz et al. 2003) with complex air-bearing mechanism design and high cost.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.6
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• pp.625-635
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• 2014

Multiple strips are required for large area mapping using ALS (Airborne Laser Scanner) system. LiDAR (Light Detection And Ranging) data collected from the ALS system has discrepancies between strips due to systematic errors of on-board laser scanner and GPS/INS, inaccurate processing of the system calibration as well as boresight misalignments. Such discrepancies deteriorate the overall geometric quality of the end products such as DEM (Digital Elevation Model), building models, and digital maps. Therefore, strip adjustment for minimizing discrepancies between overlapping strips is one of the most essential tasks to create seamless point cloud data. This study implemented area-based matching (ABM) to determine conjugate features for computing 3D transformation parameters. ABM is a well-known method and easily implemented for this purpose. It is obvious that the exact same LiDAR points do not exist in the overlapping strips. Therefore, the term "conjugate point" means that the location of occurring maximum similarity within the overlapping strips. Coordinates of the conjugate locations were determined with sub-pixel accuracy. The major drawbacks of the ABM are sensitive to scale change and rotation. However, there is almost no scale change and the rotation angles are quite small between adjacent strips to apply AMB. Experimental results from this study using both simulated and real datasets demonstrate validity of the proposed scheme.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.742-749
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• 2009

The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1159-1166
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• 2009

The use of cone-beam computed tomography(CBCT) has been proposed for guiding the delivery of radiation therapy. A kilovoltage imaging system capable of radiography, fluoroscopy, and cone-beam computed tomography(CT) has been integrated with a medical linear accelerator. A standard clinical linear accelerator, operating in arc therapy mode, and an amorphous-silicon (a-Si) with an on-board electronic portal imager can be used to treat palliative patient and verify the patient's position prior to treatment. On-board CBCT images are used to generate patient geometric models to assist patient setup. The image data can also, potentially, be used for dose reconstruction in combination with the fluence maps from treatment plan. In this study, the accuracy of Hounsfield Units of CBCT images as well as the accuracy of dose calculations based on CBCT images of a phantom and compared the results with those of using CT simulator images. Phantom and patient studies were carried out to evaluate the achievable accuracy in using CBCT and CT stimulator for dose calculation. Relative electron density as a function of HU was obtained for both planning CT stimulator and CBCT using a Catphan-600 (The Phantom Laboratory, USA) calibration phantom. A clinical treatment planning system was employed for CT stimulator and CBCT based dose calculations and subsequent comparisons. The dosimetric consequence as the result of HU variation in CBCT was evaluated by comparing MU/cCy. The differences were about 2.7% (3-4MU/100cGy) in phantom and 2.5% (1-3MU/100cGy) in patients. The difference in HU values in Catphan was small. However, the magnitude of scatter and artifacts in CBCT images are affected by limitation of detector's FOV and patient's involuntary motions. CBCT images included scatters and artifacts due to In addition to guide the patient setup process, CBCT data acquired prior to the treatment be used to recalculate or verify the treatment plan based on the patient anatomy of the treatment area. And the CBCT has potential to become a very useful tool for on-line ART.)

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1058-1068
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• 2008

This study was conducted to establish size specification of food material for elementary school meals, researched at school meal scene and surveyed with questionnaires about the management of food materials by workers devoted to preparing school meals. Most subjects (80.7%) answered that students were served smaller size than adults, whereas 11.0% answered that they served different sizes according to school age and 8.3%, that they served same size as adult. About the food material size specification for elementary school student, a majority of respondents reported that 3/4 or 2/4 of adult served size was suitable. The serving size was decided and executed to investigate the actual intake and the preference of students for food size by 2 methods, intake ratio and questionnaire in 6 elementary schools. It showed that intake ratio and preference of students may be changed by serving size. According to the result, food serving size was divided in 3 types per menu and food size was measured precisely using the white board inscripted calibration. Actual food serving size for adult and recommended food serving size for elementary school student was compared. The data collected were coded and used to decide food material specifications for 12 cooked vegetable items, 15 raw vegetable items, 9 kimchi items, 2 fermented fish and fish sauce items, 8 deep-fried items, 5 meat and meat product items, 19 fish items and 5 dried food items.