• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.407-418
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• 2018

The frequency and risk of disasters are increasing due to environmental and social factors. In order to respond effectively to disasters that occur unexpectedly, it is very important to quickly obtain up-to-date information about target area. It is possible to intuitively judge the situation about the area through the image-map generated at high speed, so that it can cope with disaster quickly and effectively. In this study, we propose an image-map generation and visualization system from UAV images for real-time disaster monitoring. The proposed system consists of aerial segment and ground segment. In the aerial segment, the UAV system acquires the sensory data from digital camera and GPS/IMU sensor. Communication module transmits it to the ground server in real time. In the ground segment, the transmitted sensor data are processed to generate image-maps and the image-maps are visualized on the geo-portal. We conducted experiment to check the accuracy of the image-map using the system. Check points were obtained through ground survey in the data acquisition area. When calculating the difference between adjacent image maps, the relative accuracy was 1.58 m. We confirmed the absolute accuracy of the image map for the position measured from the individual image map. It is confirmed that the map is matched to the existing map with an absolute accuracy of 0.75 m. We confirmed the processing time of each step until the visualization of the image-map. When the image-map was generated with GSD 10 cm, it took 1.67 seconds to visualize. It is expected that the proposed system can be applied to real - time monitoring for disaster response.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.2
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• pp.29-37
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• 2012

An experiment for an optimized automatic greenhouse environment in a flower farming greenhouse by building a ubiquitous sensor network with various sensors was conducted and the results were evaluated. And various culturing environmental information and data in the greenhouse were collected and analyzed. Then, the greenhouse was designed to maintain the best culturing environment on the basis of existing recommended optimized figures. By measuring the growth of the crops in the greenhouse, A system which controls facilities in the greenhouse to maintain the best culturing environment in accordance with change in the environment was analyzed.Computer simulation result proced that we discovered that controlling the facilities and the artificial light source increased production, enhanced quality, reduced labor and heating cost immensely. The experiment has proved that the u-flower farming system can maximize the income of farm families by sending warning messages to users of this system when weather suddenly changes so that users may cope with such changes and maintain the best culturing environment.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.42-50
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• 2008

The real-time bio-signal monitoring system based on the ZigBee and SIP/RTP has proposed and implemented for telemedicine but that has some problems at the stabilities to transmit bio-signal from the sensors to the other sides. In this paper, we designed and implemented a real-time bio-signal monitoring system that is focused on the reliability and efficiency for transmitting bio-signal at real-time. We designed the system to have enhanced architecture and performance in the ubiquitous sensor network, SIP/RTP real-time transmission and management of the database. The Bluetooth network is combined with ZigBee network to distribute traffic of the ECG and the other bio-signal. The modified and multiplied RTP session is used to ensure real-time transmission of ECG, other bio-signals and speech information on the internet. The modified ECG compression method based on DWLT and MSVQ is used to reduce data rate for storing ECG to the database. Finally we implemented a system that has improved performance for transmitting bio-signal from the sensors to the monitoring console and database. This implemented system makes possible to make various applications to serve U-health care services.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.599-608
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• 2015

In this present study, we quantified the $SO_2$ effect on $O_3$ retrieval from the Ozone Monitoring Instrument (OMI) measurement. The difference between OMI-Total Ozone Mapping Spectrometer (TOMS) and OMI-Differential Optical Absorption Spectrometer (DOAS) total $O_3$ is calculated in high $SO_2$ volcanic plume on several volcanic eruptions (Anatahan, La Cumbre, Sierra Negra, and Piton) from 2005 through 2008. There is a certain correlation ($R{\geq}0.5$) between the difference and $OMI-SO_2$ in volcanic plumes and the significant difference close to 100 DU. The high $SO_2$ condition found to affect TOMS $O_3$ retrieval significantly due to a strong $SO_2$ absorption at the TOMS $O_3$ retrieval wavelengths. Besides, we calculated the difference against various $SO_2$ levels. There is the considerable difference (average = 32.9 DU; standard deviation = 13.5 DU) in the high $OMI-SO_2$ condition ($OMI-SO_2{\geq}7.0DU$). We also found that the rate of change in the difference per 1.0 DU change in middle troposphere (TRM) and upper troposphere and stratosphere (STL) $SO_2$ columns are 3.9 DU and 4.9 DU, respectively.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.523-530
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• 2015

A Multiple Regression Method (MRM) is used for the first time with Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to estimate formaldehyde (HCHO) Vertical Column Density (VCD). For a 3.5-year period from January 2005 through July 2008, HCHO VCD estimation is investigated in cities over Asia in two categorized areas: (1) Major cities in Northeast Asia (Beijing, Seoul, and Tokyo), (2) Major cities in Southeast Asia (New Delhi, Dhaka, and Bangkok). In the Major cities in Northeast Asia, there are good agreements between HCHO estimated by the multiple linear regression method ($HCHO_{MRM}$) and HCHO measured by OMI ($HCHO_{OMI}$) (0.78 < $R^2$ < 0.82). However, in Major cities in Southeast Asia, there were poor agreements between $HCHO_{OMI}$ and $HCHO_{MRM}$ (0.24 < $R^2$ < 0.39). In addition, an unbiased assessment of the MRM performance using modeling and validation groups shows that the performance of the MRM based on separate modeling and validation groups is comparable to that using all the data for deriving Multiple Regression Equations (MREs). This study demonstrates that MRM can be an alternative tool for HCHO estimation in certain areas over Asia.

• Korean Journal of Remote Sensing
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• v.19 no.4
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• pp.277-284
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• 2003

We present a GPS-derived regional ionosphere model, which estimates Total Electron Content (TEC) in a rectangular grid on the spherical shell over Korea. After dividing longitude and latitude over Korea with 1$^{\circ}$$\times$1$^{\circ}$ spatial resolution, the TEC at the vertex of the grid was estimated by the Kalman filter. The GPS data received from nine nationwide GPS stations, operated by Korea Astronomy Observatory (KAO), were used for this study. To reduce inherent noises, the pseudorange data were phase-leveled by a linear combination of pseudoranges and carrier phases. The solar-geomagnetic reference frame, which is less variable to the ionosphere movement due to the Sun and the geomagnetic field than an Earth-fixed frame, was used. During a quiet time of solar activity, the KAO's regional ionosphere map indicated 30-45 Total Electron Content Unit at the peak of the diurnal variation. In comparison with the Global ionosphere Map of the Center for Orbit Determination in Europe, RMS differences were at the level of 4-5 TECU for five days.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.273-285
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• 2005

This study has investigated the suitable wavelength for detecting biomass burning aerosols. We have performed the analysis of the wavelength at 380nm in near-UV, 400nm, 412nm, 460nm, and 490nm in visible, and 2100nm in shortwave infrared regions from the Global Imager measurements. It is well known that the UV bands have the advantage of the aerosols retrieval due to the low surface reflectance and a weak effect of Bidirectional Reflectivity Distribution Function. However, the pure surface reflectances of shortwave visible bands, except 412nm, are as low as that of 380nm in near-UV over northeast Asia. In order to detect the aerosol signal, we have retrieved the aerosol reflectance as a function of wavelength based on the surface reflectivity contrast method for the period of May 2003. It is interesting that the retrieved aerosol reflectance with 460nm is slightly more sensitive than that with 380nm. Additionally, we have applied the TOMS aerosol index method to determine the best pair for biomass burning aerosols and found that the pair of 380 and 460nm results in the best signal for retrieving aerosols.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.303-316
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• 2005

Strong radar returns were observed in oyster sea farms, and coherent interferometric pairs were successfully constructed. Tide height in coastal area is possible to be measured by using interferometric phase and intensity of SAR data. This SAR application technique for measuring the tide height in the near coastal zone can be further improved when applied to double bounce dominant areas. In this paper, we investigate the characteristics of polarimetric signature in the oyster farm structures. Laboratory experiments were carried out using Ku-band according to the target scale. Radar returns from vertical poles are stronger than those from horizontal Pole by 10.5 dB. Single bounce components were as strong as double bounce components and more sensitive to antenna look direction. Double bounce components show quasi-linear relation with the height of vertical poles, which implies double bounce is more useful to determine water level than total power. A L-band NASA/IPL airborne SAR (AIRSAR) image was classified into single-, double-bounce, and volume scattering components. It is observed that oyster farms are not always characterized by double bounced scattering. Double bounce is a main scattering mechanism in oyster farms standing above seawater, while single bounce is stronger than double bounce when bottom tidal flats are exposed to air. Ratios of the normalized single to double bounce components in the former and latter cases were 0.46 and 5.62, respectively. It is necessary to use double bounce dominant sea farms for tide height measurement by DInSAR technique.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.593-603
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• 2010

Most spatial data acquisition systems employing a set of frame cameras may have suffered from their small fields of view and poor base-distance ratio. These limitations can be significantly reduced by employing an omni-directional camera that is capable of acquiring images in every direction. Bundle Block Adjustment (BBA) is one of the existing georeferencing methods to determine the exterior orientation parameters of two or more images. In this study, by extending the concept of the traditional BBA method, we attempt to develop a mathematical model of BBA for omni-directional images. The proposed mathematical model includes three main parts; observation equations based on the collinearity equations newly derived for omni-directional images, stochastic constraints imposed from GPS/INS data and GCPs. We also report the experimental results from the application of our proposed BBA to the real data obtained mainly in urban areas. With the different combinations of the constraints, we applied four different types of mathematical models. With the type where only GCPs are used as the constraints, the proposed BBA can provide the most accurate results, ${\pm}5cm$ of RMSE in the estimated ground point coordinates. In future, we plan to perform more sophisticated lens calibration for the omni-directional camera to improve the georeferencing accuracy of omni-directional images. These georeferenced omni-directional images can be effectively utilized for city modelling, particularly autonomous texture mapping for realistic street view.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.571-580
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• 2010

Coastal shoreline movement due to erosion and deposition is a major concern for coastal zone management. Shoreline is changed by nature factor or development of coastal. Change of shoreline is threatening marine environment and destroying. Therefore, we need monitoring of shoreline change with time series analysis for coastal zone management. In this study, we analyzed the shoreline change using airphotograph, LiDAR and satellite imagery from 1971 to 2009 in Uljin, Gyeongbuk, Korea. As a result, shoreline near of the nuclear power plant show linear pattern in 1971 and 1980, however the pattern of shoreline is changed after 2000. As a result of long-term monitoring, shoreline pattern near of the nuclear power plant is changed by erosion toward sea. The pattern of shoreline near of KORDI until 2003 is changed due to deposition toward sea, but the new pattern toward land is developed by erosion from 2003 to 2009. The shoreline is changed by many factors. However, we will guess that change of shoreline within study area is due to construction of nuclear power plant. In the future work, we need sedimentary and physical studies.