• Journal of Korean Society for Geospatial Information Science
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• v.11 no.4 s.27
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• pp.21-27
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• 2003

The rational polynomial coefficients(RPC) model is a generalized sensor model that is used as an alternative for the physical sensor model for IKONOS-2 and QuickBird. As the number of sensors increases along with greater complexity, and as the need for standard sensor model has become important, the applicability of the RPC model is also increasing. The RPC model can be substituted for all sensor models, such as the projective camera the linear pushbroom sensor and the SAR This paper is aimed at generating a RPC model from the physical sensor model of the KOMPSAT-1(Korean Multi-Purpose Satellite) and aerial photography. The KOMPSAT-1 collects $510{\sim}730nm$ panchromatic images with a ground sample distance (GSD) of 6.6m and a swath width of 17 km by pushbroom scanning. We generated the RPC from a physical sensor model of KOMPSAT-1 and aerial photography. The iterative least square solution based on Levenberg-Marquardt algorithm is used to estimate the RPC. In addition, data normalization and regularization are applied to improve the accuracy and minimize noise. And the accuracy of the test was evaluated based on the 2-D image coordinates. From this test, we were able to find that the RPC model is suitable for both KOMPSAT-1 and aerial photography.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.42-51
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• 2012

Objectives: To compare the exposure level of extremely low frequency (ELF) magnetic fields among semiconductor workers, shipyard welders and office workers. Methods: To measure the ELF magnetic field concentration, EMDEX LITE (Enertech, USA) were used and monitored for eight hours continuously. Five companies handling the electric and magnetic field (EMF) source were investigated, which the exposure groups were classified into three groups: semiconductor workers, welders, and office workers. Welder group was chosen as a high exposed group and office group as a low exposed group. Results: The arithmetic mean (${\pm}SD$) and geometric mean (GSD) of personal exposure level of semiconductor workers were 0.73 (${\pm}1.33$) ${\mu}T$, 0.43 (2.88) ${\mu}T$, respectively. The ceiling value ranged between 0.18 and 123.2 ${\mu}T$. Welders were exposed high with the arithmetic mean value of 3.46 (${\pm}\;13.46$) ${\mu}T$ and geometric mean value of 0.45 (4.70) ${\mu}T$, respectively, and ceiling value range of 75.5~129.6 ${\mu}T$. The exposure levels of office workers were low compared to other exposed groups; the arithmetic mean 0.05 (${\pm}0.13$) ${\mu}T$, geometric mean 0.03 (2.38) ${\mu}T$ and ceiling value range 0.37~3.35 ${\mu}T$. This study revealed statistically significant differences of the mean ELF magnetic field exposure doses among three groups (p < 0.01). Conclusions: The average ELF magnetic field exposure doses of semiconductor workers were much higher than those of office workers in control group, but were lower than those of welders in high exposure group.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.223-231
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• 1998

Ocean Scanning Multispectral Imager (OSMI) is a payload on the Korean Multi-Purpose SATellite (KOMPSAT) to perform worldwide ocean color monitoring for the study of biological oceanography. The instrument images the ocean surface using a whisk-broom motion with a swath width of 800 km and a ground sample distance (GSD) of less than 1 km over the entire field-of-view (FOV). The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/offset and on-orbit image data storage. The instrument also performs sun calibration and dark calibration for on-orbit instalment calibration. The OSMI instrument is a multi-spectral imager covering the spectral range from 400 nm to 900 nm using a Charge Coupled Device (CCD) Focal Plane Array (FPA). The ocean colors are monitored using 6 spectral channels that can be selected via ground commands after launch. The instrument performances are fully measured for 8 basic spectral bands centered at 412, 443, 490, 510, 555, 670, 765 and 865 nm during ground characterization of instalment. In addition to the ground calibration, the on-orbit calibration will also be used for the on-orbit band selection. The on-orbit band selection capability can provide great flexibility in ocean color monitoring.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1573-1587
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• 2021

A Drone image is an ultra-high-resolution image that is several or tens of times higher in spatial resolution than a satellite or aerial image. Therefore, drone image-based remote sensing is different from traditional remote sensing in terms of the level of object to be extracted from the image and the amount of data to be processed. In addition, the optimal scale and size of data used for model training is different depending on the characteristics of the applied deep learning model. However, moststudies do not consider the size of the object to be found in the image, the spatial resolution of the image that reflects the scale, and in many cases, the data specification used in the model is applied as it is before. In this study, the effect ofspatial resolution and image size of drone image on the accuracy and training time of the semantic segmentation deep learning model of six wintering vegetables was quantitatively analyzed through experiments. As a result of the experiment, it was found that the average accuracy of dividing six wintering vegetablesincreases asthe spatial resolution increases, but the increase rate and convergence section are different for each crop, and there is a big difference in accuracy and time depending on the size of the image at the same resolution. In particular, it wasfound that the optimal resolution and image size were different from each crop. The research results can be utilized as data for getting the efficiency of drone images acquisition and production of training data when developing a winter vegetable segmentation model using drone images.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.21-30
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• 2022

Objectives: The purpose of this study is to suggest an optimal method by comparing the analysis methods of work environment measurement datasets including left-censored data where one or more measurements are below the limit of detection (LOD). Methods: A computer program was used to generate left-censored datasets for various combinations of censoring rate (1% to 90%) and sample size (30 to 300). For the analysis of the censored data, the simple substitution method (LOD/2), β-substitution method, maximum likelihood estimation (MLE) method, Bayesian method, and regression on order statistics (ROS)were all compared. Each method was used to estimate four parameters of the log-normal distribution: (1) geometric mean (GM), (2) geometric standard deviation (GSD), (3) 95th percentile (X95), and (4) arithmetic mean (AM) for the censored dataset. The performance of each method was evaluated using relative bias and relative root mean squared error (rMSE). Results: In the case of the largest sample size (n=300), when the censoring rate was less than 40%, the relative bias and rMSE were small for all five methods. When the censoring rate was large (70%, 90%), the simple substitution method was inappropriate because the relative bias was the largest, regardless of the sample size. When the sample size was small and the censoring rate was large, the Bayesian method, the β-substitution method, and the MLE method showed the smallest relative bias. Conclusions: The accuracy and precision of all methods tended to increase as the sample size was larger and the censoring rate was smaller. The simple substitution method was inappropriate when the censoring rate was high, and the β-substitution method, MLE method, and Bayesian method can be widely applied.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.2
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• pp.93-101
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• 2016

Purpose: McArdle disease, glycogen storage disease type V (GSD V), is one of the most common adolescent-onset glycogen storage diseases. It is caused by recessive mutations in PYGM encoding myophosphorylase, which is critical to glycogen metabolism. Since only a few korean patients have been reported, we will observe the clinical and genetic features of three korean patients with McArdle disease. Methods: We retrospectively reviewed the medical records of three patients with genetically confirmed McArdle disease, including the results of forearm ischemic exercise test, electromyogram, nerve conduction velocity, muscle biopsy, and PYGM analysis in peripheral leukocytes. Results: All three cases were males and their age of symptom onset was 12, 5, 14 years old, respectively. A high basal level of serum creatine kinase was noted in all three patients. They experienced the recurrent episodes of rhabdomyolysis, but second wind phenomenon was not definite. In muscle biopsy, subsarcolemmal space vacuoles including periodic acid schiff stained materials were found in two patients, while no evidence of glycogen storage disease was found in the other. A total of five different mutations, $p.Arg50^*$, p.Trp798Arg, $p.Arg50^*$, p.Glu779del, $p.Asp511Thrfs^*28$ and p.Phe710del, were found in three patients. Avoidance of isometric exercise, aerobic exercise and glucose intake before each exercise were recommended for all patients. Conclusion: The three Korean patients with McArdle disease showed the typical manifestations of the condition. The most mutations were private. Therefore, identification of more cases with long-term follow-up will be required to understand the clinical and genetic features of this disease among Korean population.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.1
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• pp.77-84
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• 2020

This study is apply 3D spatial information per traditional landscape space by comparing spatial information data created using a small drone and 3D scanner used for 3D spatial information construction for efficient preservation and management of traditional landscaping space composed of areas such as scenic sites and traditional landscape architectures. The analysis results are as follows. First, aerial photogrammetry data is less accurate than 3D scanners, but it was confirmed to be more suitable for monitoring landscape changes by reading RGB images than 3D scanners by texture mapping using digital data in constructing orthographic image data. Second, the orthographic image data constructed by aerial photogrammetry in a traditional landscaping space consisting of a fixed area, such as Gwanghalluwon Garden, produced visually accurate and precise results. However, as a result of the data extraction, data for trees, which is one of the elements that make up the traditional landscaping, was not extracted, so it was determined that 3D scanning and aerial surveying had to be performed in parallel, especially in areas where trees were densely populated. Third, The surrounding trees in Soswaewon Garden caused many errors in 3D spatial information data including topographic data. It was analyzed that it is preferable to use 3D scanning technology for precise measurement rather than aerial photogrammetry because buildings, landscaping facilities and trees are dense in a relatively small space. When 3D spatial information construction data for a traditional landscaping space composed of area using a small drone and a 3D scanner free from temporal and spatial constraints and compared the data was compared, the aerial photogrammetry is effective for large site such as Hahoe Village, Gyeongju and construction of a 3D space using a 3D scanner is effective for traditional garden such as Soswaewon Garden.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.213-222
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• 1998

Electro-Optical Camera(EOC) is the main payload of the KOrea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including a Digital Terrain Elevation Map(DTEM). This instalment which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510~730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response, the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the users of EOC data. The modulation transfer function of EOC was measured as greater than 16 % at Nyquist frequency over the entire field of view, which exceeds its requirement of larger than 10 %. The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.