• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.537-547
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• 2010

The importance of vegetation in studies of global climate and biogeochemical cycles is well recognized. Especially. the FPAR (fraction of photosynthetically active radiation) is one of the important parameters in ecosystem productivity and carbon budget models. Therefore, accurate estimates of vegetation parameters are increasingly important in environmental impact assessment studies. In this study, optical FPAR using the Terra MODIS (MODerate resolution Imaging Spectroradiometer), SPOT VEGETATION and ECOCLIMAP data reproduced on the Korean peninsula. We applied the empirical method which is usually estimated as a linear or nonlinear function of vegetation indices. As results, we estimated the accurate expression which is 0.9039 of $R^2$ in cropland and 0.7901 of $R^2$ in forest. Finally, this study could be demonstrated to calibrate that produced FPAR while the overall pattern and random noise through the comparative analysis of FPAR on the reference data. Optimal use of input parameter on the Korean peninsula should be helping the accuracy of output as well as the improved quality of research.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.71-78
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• 2019

Most 3D displays that are currently in the market adopt the binocular disparity method creating a different image for the left and right eye for a 3 dimensional effect. However, commercialized 3D image output devices lack in performance making it uncomfortable for the viewer and restrict the viewer to certain positions. In this paper, we propose a single-cell polarized lens type stereoscopic system which has a smaller viewing angle and reduced crosstalk, with improved light penetration compared to existing double-cell structures; and analyzed the single-cell polarized lens type stereoscopic system properties, and conducted an effect analysis of performance improvement compared to the dual-cell type. Results showed that the single-cell type had a 25% improved performance, and the 3D crosstalk index which is an important index for quality characteristics of stereoscopic systems, increased over about 37%, compared to the dual-cell type.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.181-186
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• 2019

In order to reduce the fossil fuels consumed in conventional commercial independent diesel generators in the same environment as the island area, it is necessary to develop a photovoltaic system that will bear more than 40% of the independent system capacity. For this development, it is necessary to develop a high-capacity inverter that can improve the stability of the independent system installed in the island area and supply high-quality power to the load. In addition, the EMS power generation control system for the independent grid photovoltaic power generation system is a parallel operation power control system of the diesel generator connected with the solar power generation system. It controls the output of the diesel generator according to the load ratio and the solar power generation, A stable supply system is needed. This independent grid photovoltaic generation system can increase the solar power supply to the independent system area and increase the power stability of the independent system and further reduce the use of fossil fuel due to the ineffective power control of the independent system. It is expected that the economy will be secured early.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.533-542
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• 2015

This paper suggest away to maintain constant power through trolley wire by transferring increased line voltage to the AC main line while changing the mode from Converter(Forward) to Inverter(Reverse) when the line voltage is increased due to regenerative power when the train stops, This paper suggests a Double Converter DC substation that can create regenerative power when the train stops reusable. We also proposed using a simulation tool, the optimal Thyrister firing angle that can minimize the undershoot and overshoot that occurs when transferring the mode from Converter to Inverter for quality improvement of DC voltage in the Double Converter in the DC substation from the Busan Urban Subway.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3018-3025
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• 2021

The authors developed a volumetric dosimetry detector system using in-house 3D-printable plastic scintillator resins. Three tumor model scintillators (TMSs) were developed using magnetic resonance images of a tumor. The detector system consisted of a TMS, an optical fiber, a photomultiplier tube, and an electrometer. The background signal, including the Cherenkov lights generated in the optical fiber, was subtracted from the output signal. The system showed 2.1% instability when the TMS was reassembled. The system efficiencies in collecting lights for a given absorbed energy were determined by calibration at a secondary standard dosimetry laboratory (k_SSDL) or by calibration using Monte Carlo simulations (k_sim). The TMSs were irradiated in a Gamma Knife® Icon^TM (Elekta AB, Stockholm, Sweden) following a treatment plan. The energies absorbed to the TMSs were measured and compared with a calculated value. While the measured energy determined with k_SSDL was (5.84 ± 3.56) % lower than the calculated value, the energy with k_sim was (2.00 ± 0.76) % higher. Although the TMS detector system worked reasonably well in measuring the absorbed energy to a tumor, further improvements in the calibration procedure and system stability are needed for the system to be accepted as a quality assurance tool.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.485-488
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• 2016

The level of domestic greenhouse complex environmental control technology is a hardware-oriented automation steps that mechanically control the environments of greenhouse, such as temperature, humidity and $CO_2$ through the technology of cultivation and consulting experts. This automation brings simple effects such as labor saving. However, in order to substantially improve the output and quality of agricultural products, it is essential to track the growth and physiological condition of the plant and accordingly control the environments of greenhouse through a software-based complex environmental control technology for controlling the optimum environment in real time. Therefore, this paper is a part of general methods on the greenhouse complex environmental control technology. and presents a horticulture production forecasting methods using artificial neural networks through the analysis of big data systems of smart farm performed in our country and artificial neural network technology trends.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.117-121
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• 2019

In this study, research and a demonstration for applying DC distribution systems to ships as an environmental and energy conservation solution in domestic and foreign countries were actively carried out. In order to apply a generator to a DC distribution system, a variable speed engine was used. Both engine speed and fuel consumption were reduced. In this paper, a DC generator for DC distribution was constructed using a diesel generator, a generator controller, a governor, and an AVR. A system configuration method for a generator, power quality test, and the power characteristics of a variable speed generator were analyzed. The voltage (250 - 440 VAC) and frequency (34 - 60 Hz) of the variable speed generator were set to 60 - 100 % of the rated value, and the engine was set to operate from 1100 - 1800 rpm. It was confirmed that the voltage, current, and frequency of the generator output fluctuated in a stable manner according to the power amount when changing the engine speed of the generator according to the load variation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1359-1368
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• 2021

Steganography is a science of embedding secret data into innocent data and its goal is to conceal the existence of a carrier data. Many research on Steganography has been proposed by various hiding and detection techniques that are based on different algorithms. On the other hand, very few studies have been conducted to analyze the performance of each Steganography software. This paper describes five different Steganography software, each having its own algorithms, and analyzes the difference of each inherent feature. Image quality metrics of Peak Signal to Noise Ratio (PSNR) and Structural SIMilarity (SSIM) are used to define its performance of each Steganography software. We extracted PSNR and SSIM results of a quantitative amount of embedded output images for those five Steganography software. The results will show the optimal steganography software based on the evaluation metrics and ultimately contribute to forensics.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.465-470
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• 2021

A robust speech recognition technology is required that does not degrade the performance of speech recognition and the quality of the speech when speech recognition is performed in an actual environment of the speech mixed with noise. With the development of such speech recognition technology, it is necessary to develop an application that achieves stable and high speech recognition rate even in a noisy environment similar to the human speech spectrum. Therefore, this paper proposes a speech enhancement algorithm that processes a noise suppression based on the MMSA-STSA estimation algorithm, which is a short-time spectral amplitude method based on the error of the least mean square. This algorithm is an effective nonlinear speech enhancement algorithm based on a single channel input and has high noise suppression performance. Moreover this algorithm is a technique that reduces the amount of distortion of the speech based on the statistical model of the speech. In this experiment, in order to verify the effectiveness of the MMSA-STSA estimation algorithm, the effectiveness of the proposed algorithm is verified by comparing the input speech waveform and the output speech waveform.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.2
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• pp.127-137
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• 2019

Low-rise residential community is the most popular type (51%) of residential neighborhoods in Seoul. Currently, there is a shortage of public facilities needed for living conditions and the quality of life in low-rise residential areas. This study defines 'public facility' as infrastructure to improve the living environment and used by residents jointly in low-rise residential areas. In this regard, this study analyzes current legal and institutional standards, latest trends in public facility of apartments, and residents' demand and satisfaction level in order to find out the criteria for installation of priority public facilities. As a result, the essential facility basically conforms to the number of household which is the standard of the facility supply in apartment. However, considering the limitations on the accessibility due to low density, it should consider two standards at the same time: the number of household and distance (radius of neighborhood). In conclusion, it is necessary to install legally prescribed facilities according to the number of household and distance: 500 households facilities in 250m radius neighborhood and 1,000 households facilities in 400m radius neighborhood. Also, considering the reality of low-rise residential area, it is necessary to integrate some facilities that can be functionally linked to improve level of utility and efficiency of operation and management. It is expected that the output of this study can be applied to institutionalize of the legal basis for the public facility of low-rise residential community.