IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium
Red tide is a type of harmful algal bloom that may cause detrimental effects on the coastal envir... more Red tide is a type of harmful algal bloom that may cause detrimental effects on the coastal environment as well as to the aquaculture farms in the coastal zone. This study investigates the use of a multispectral camera onboard an unmanned aerial vehicle for mapping red tide intensity in oceanic waters. After the high altitude observation with the due observation geometry and the preprocessing steps, red tide patches which occurred in the southern coast of Korea around Yeosu were successfully identified with the system, producing red tide intensity images over the study areas.
In this paper, we introduce a monitoring method for flow expansion and contraction in a simple fl... more In this paper, we introduce a monitoring method for flow expansion and contraction in a simple flow phantom based on electrical resistance changes in an epidermal strain sensor attached to the phantom. The flow phantom was fabricated to have a nonflat surface and small modulus that are analogous to human skin. The epidermal sensors made of polydopamine and polyvinyl alcohol show sufficient linearity (R = 0.9969), reproducibility, and self-adhesion properties, as well as high sensitivity to small modulus measurements (<1% tensile strain). Pulsatile flow monitoring experiments were performed by placing the epidermal sensor on the flow phantom and measuring the relative changes in resistance by the heartbeat. Experiments were conducted for three types of vessel diameters (1.5, 2, and 3 mm). In each of the experiments, the vessels were divided into Top, Middle, and Bottom positions. Experiments for each position show that the relative changes in resistance increase proportionally wit...
Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide... more Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of controlling the reaction process should be used. Additionally, when a homogeneous base catalyst is used, a neutralization process is required to remove residual bases after the reaction, and it is also difficult to separate the catalyst and the product. Therefore, in this study, we report the results of SPA prepared from the reaction of SP and EC using only heterogeneous base catalysts. The heterogeneous base catalyst was obtained by supporting KOH on La 2 O 3 and calcintion. Using EC instead of EO, it was possible to produce SPA under the atmospheric rather than high-pressure reaction condition. Average molecular weights of synthesized SPA varied greatly depending on reaction conditions. The average molecular weight of SPA prepared using the KOH/La 2 O 3 catalyst could be controlled arbitrarily by controlling the reaction temperature and added catalyst and EC amounts.
In this study, aluminum alloy sheet was welded on I-butt joint using AC type TIG welding machine.... more In this study, aluminum alloy sheet was welded on I-butt joint using AC type TIG welding machine. Welding conditions were designed with CCD(Central Composite Design) method in which input variables were welding current and travel speed. TIG welding was done on A6061 alloy sheet for the welding conditions at Ar shielding. The second-order regression equation was obtained using Minitab R18 with the bead shape measured from TIG welded samples. The optimum weld bead shape selected from the surface response graphs was effective penetration depth 1.78mm, upper bead width 5.36mm and sagging 0.39mm. And the correspond welding condition was welding current 115A and travel speed 5.7m/min. The reliability of the calculated regression equation for bead shape was varied from 90% of sagging to 98.7% of upper bead width.
Journal of Mechanical Science and Technology, 2017
We improve the performance of a low-quality GPS data on a UGV through use of multiple low-quality... more We improve the performance of a low-quality GPS data on a UGV through use of multiple low-quality GPS modules on a UGV within line of sight of the UAV. The UGV sends GPS data corrections to the UAV on the basis of the distance from the UAV to the UGV as measured by scaling of a standard image pattern stuck on the UGV. Geolocation of both UGV and UAV are performed through the use of the extended Kalman filter integrating GPS aided INS. The positioning error is reduced by a factor of 2.3 in simulation studies and a factor of 1.6 in experiment when 3 GPS sensors are used on the UGV. This is better than what one can get through pure averaging of the GPS sensors in the presence of noise in measuring the UAV-UGV distance. We show how our exploitation of geometry improves GPS sensor performance as more GPS sensors are used.
In this study, aluminum alloy sheets were welded on bead-on-plate using AC type TIG welding machi... more In this study, aluminum alloy sheets were welded on bead-on-plate using AC type TIG welding machine. Penetration depth and bead width were selected as quality factors of weld bead. Welding conditions were designed with BBD(Box-Benhken Design) method in which the input variables were welding current, arc length and travel speed. TIG welding was done on A6061 alloy sheet for the welding conditions selected by DOE at Ar shielding. The second-order regression equation was obtained using the bead shape measured from TIG welded samples. Verification test was done at the optimum welding condition determined by the surface response diagram derived from the regression equation. The optimum welding condition was welding current 110A, arc length 1.4mm and travel speed 9.6mm/s. The penetration depth and the bead width formed at the predicted optimum welding condition were 1.97±0.010mm and 4.65±0.051mm. From the result, the regression equation matched with real TIG welding in accuracy 98.5% and 96.8% for penetration depth and bead width respectively.
We show a new scheme and implementation of maritime data communication systems for GMDSS ship whi... more We show a new scheme and implementation of maritime data communication systems for GMDSS ship which performs e-Navigation and removes the functional limitation of those systems through comparing to service fee, call processing reliability, and bit rates of all of those systems within communication range at sea. We confirmed available each frequency band communication and application services at sea by experimental result with proposed new system, MF/HF band being useful to a short text message service, VHF band to 9600bps email service, Fleet Broadband Maritime Satellite system to one or more Mbps multimedia service each.
We developed an octocopter-based unmanned aerial system (UAS) to monitor remote environments. The... more We developed an octocopter-based unmanned aerial system (UAS) to monitor remote environments. The system contains various environmental monitoring sensors for measuring wind speed/direction, temperature, relative humidity, atmospheric pressure, fine dust, and multispectral and RGB data. The UAS consists of an unmanned aerial vehicle (UAV), a ground control station, and a server. We studied its electrical, mechanical, and software (SW) configurations. Specifically, we developed hardware (HW) and SW to control the yaw and gimbal pitch directions of the UAV conveying multispectral and RGB cameras. To prevent the obtained solar reflectance from affecting the multispectral and RGB data and to improve the quality of the obtained data, we maneuvered the yaw so that it would always deviate 135 • from the solar azimuth angle, with the sun at its rear. Managing the yaw direction involves controlling the UAV based on a micro air vehicle link message-based robot operating system (ROS). To safely test the UAS performance before the maiden flight in an ocean area, we first evaluated PX4 and ROS-based SW through indoor software-in-the-loop simulation (SILS) via the Gazebo tool. Subsequently, we used an F450 UAV and an actual maritime UAV to sequentially perform pre-flight and flight experiments. This paper explains the system operation scenario, UAS component, and simulation and experimental results. The results reveal that the average yaw angle error during the mission,¯ θ y,des − θ y , is approximately 8 • , and the average pitch angle of the gimbal during the mission, 50 • − θ c , is less than 5 •. INDEX TERMS Maritime environmental observation, ocean color, robot operating system, unmanned aerial system, unmanned aerial vehicle.
Styrenated phenols (SPs) are usually synthesized by the reaction of styrene and phenol under acid... more Styrenated phenols (SPs) are usually synthesized by the reaction of styrene and phenol under acid catalysts. SPs with a high content of di-styrenated phenol (DSP) can be used to prepare styrenated phenol alkoxylate (SP-A). Therefore, in this study, a scale-up process for synthesizing SPs with high DSP content which can be used for synthesis of SPA was studied. The solid catalyst used in this study was prepared by impregnation method. SO 2− 4 was impregnated on a SO 2− 4 /ZrO 2 catalyst in an aqueous 1 M H 2 SO 4 solution. The prepared catalysts were characterized by NH 3-TPD. Catalytic activity was examined by measuring the conversion of phenol and styrene in a liquid-phase batch reactor. Almost 100% conversion of both phenol and styrene over 5-SO 2− 4 /ZrO 2 catalyst was obtained at a reaction temperature of 80 C and a reaction time of 6 h. The amount of catalyst to the reactants was 2 wt%. Under the same reaction conditions, the selectivity of MSP, DSP, and TSP was 12.4%, 64.5%, and 23.1% respectively.
This study was carried out to analyze the effects of adding hydroxypropyl cellulose (HPC) on the ... more This study was carried out to analyze the effects of adding hydroxypropyl cellulose (HPC) on the rheology and dispersibility of the slurry and battery characteristics when fabricating an anode slurry containing Si alloy as the active material, a water-based binder, and deionized water as the solvent. The addition of HPC resulted in a reduction in the viscosity and excellent dispersion in the slurry. In the battery, the adhesiveness of the electrode and current collector was improved, and the initial capacity, polarization resistance, and cycling performance were improved. In addition, the expansion in thickness decreased. This was because HPC suppressed coagulation by steric hindrance and simultaneously acted as a binder by being adsorbed on the particle surfaces of the Si alloy and Ketjen black.
Small (Weinheim an der Bergstrasse, Germany), Jan 17, 2018
A feasible approach is reported to reduce the switching current and increase the nonlinearity in ... more A feasible approach is reported to reduce the switching current and increase the nonlinearity in a complementary metal-oxide-semiconductor (CMOS)-compatible Ti/SiN /p -Si memristor by simply reducing the cell size down to sub-100 nm. Even though the switching voltages gradually increase with decreasing device size, the reset current is reduced because of the reduced current overshoot effect. The scaled devices (sub-100 nm) exhibit gradual reset switching driven by the electric field, whereas that of the large devices (≥1 µm) is driven by Joule heating. For the scaled cell (60 nm), the current levels are tunable by adjusting the reset stop voltage for multilevel cells. It is revealed that the nonlinearity in the low-resistance state is attributed to Fowler-Nordheim tunneling dominating in the high-voltage regime (≥1 V) for the scaled cells. The experimental findings demonstrate that the scaled metal-nitride-silicon memristor device paves the way to realize CMOS-compatible high-densit...
Styrenated phenols (SPs) involving very small amount of unreacted phenol and high content of di-S... more Styrenated phenols (SPs) involving very small amount of unreacted phenol and high content of di-SP (DSP) were synthesized, which can be used to prepare SP alkoxylate. The solid catalyst was prepared by impregnation method. SO2-4 on SO2-4/MxOy catalyst was introduced from an aqueous 1M-H2SO4 solution. The catalysts were characterized by XRD patterns, and FT-IR spectra. The catalytic activity was examined by measuring conversion of phenol and styrene in a batch liquid-phase reactor. The concentration of phenol, styrene, and SPs were measured by GC with capillary column. The optimum synthesis conditions for concentration of sulfuric acid solution, catalyst amount of reactants, reaction temperature, and reaction time over SO2-4/ZrO2 catalyst were 15 wt%, 15 wt%, 100 °C, and 6 hr, respectively. At these conditions, conversion of both phenol and styrene were almost 100%, and the selectivity of DSP was 52.1%. On the other hand, the optimum synthesis conditions over SO2-4/TiO2 catalyst were...
Styrenated phenol was prepared by an alkylation of phenol using NiCl2 and AlCl3 supported on sili... more Styrenated phenol was prepared by an alkylation of phenol using NiCl2 and AlCl3 supported on silica gel. The conversion of phenol and styrene of alkylation reaction, and the selectivity of styrenated phenol were investigated. The Al · Ni/SiO2 Supported catalyst was used, the conversion of phenol was almost 100%. The product was in the form of a mixture of mono-styrenated phenol, di-styrenated phenol and tri-styrenated phenol. The styrenated phenol were selectivity of the varies depending on the reaction conditions.
Journal of the Korea Society of Computer and Information, 2012
The opinion of user on a certain product is expressed in positive/negative sentiments for specifi... more The opinion of user on a certain product is expressed in positive/negative sentiments for specific features of it. In some cases, they are expressed for a holistic part of homogeneous specific features, or expressed for product itself. Therefore, in the area of opinion mining, name of opinion features to be extracted are specific feature names, holonyms for theses specific features, and product names. However, when the opinion target is described with product name or holonym, sometimes it may not match feature name of opinion sentence to true opinion target intended by
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium
Red tide is a type of harmful algal bloom that may cause detrimental effects on the coastal envir... more Red tide is a type of harmful algal bloom that may cause detrimental effects on the coastal environment as well as to the aquaculture farms in the coastal zone. This study investigates the use of a multispectral camera onboard an unmanned aerial vehicle for mapping red tide intensity in oceanic waters. After the high altitude observation with the due observation geometry and the preprocessing steps, red tide patches which occurred in the southern coast of Korea around Yeosu were successfully identified with the system, producing red tide intensity images over the study areas.
In this paper, we introduce a monitoring method for flow expansion and contraction in a simple fl... more In this paper, we introduce a monitoring method for flow expansion and contraction in a simple flow phantom based on electrical resistance changes in an epidermal strain sensor attached to the phantom. The flow phantom was fabricated to have a nonflat surface and small modulus that are analogous to human skin. The epidermal sensors made of polydopamine and polyvinyl alcohol show sufficient linearity (R = 0.9969), reproducibility, and self-adhesion properties, as well as high sensitivity to small modulus measurements (<1% tensile strain). Pulsatile flow monitoring experiments were performed by placing the epidermal sensor on the flow phantom and measuring the relative changes in resistance by the heartbeat. Experiments were conducted for three types of vessel diameters (1.5, 2, and 3 mm). In each of the experiments, the vessels were divided into Top, Middle, and Bottom positions. Experiments for each position show that the relative changes in resistance increase proportionally wit...
Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide... more Styrenated phenol alkoxylates (SP-A) were prepared from styrenated phenol (SP) and ethylene oxide (EO) under a homogeneous base catalyst. However, to use EO that is difficult to handle, a high-pressure reaction device capable of controlling the reaction process should be used. Additionally, when a homogeneous base catalyst is used, a neutralization process is required to remove residual bases after the reaction, and it is also difficult to separate the catalyst and the product. Therefore, in this study, we report the results of SPA prepared from the reaction of SP and EC using only heterogeneous base catalysts. The heterogeneous base catalyst was obtained by supporting KOH on La 2 O 3 and calcintion. Using EC instead of EO, it was possible to produce SPA under the atmospheric rather than high-pressure reaction condition. Average molecular weights of synthesized SPA varied greatly depending on reaction conditions. The average molecular weight of SPA prepared using the KOH/La 2 O 3 catalyst could be controlled arbitrarily by controlling the reaction temperature and added catalyst and EC amounts.
In this study, aluminum alloy sheet was welded on I-butt joint using AC type TIG welding machine.... more In this study, aluminum alloy sheet was welded on I-butt joint using AC type TIG welding machine. Welding conditions were designed with CCD(Central Composite Design) method in which input variables were welding current and travel speed. TIG welding was done on A6061 alloy sheet for the welding conditions at Ar shielding. The second-order regression equation was obtained using Minitab R18 with the bead shape measured from TIG welded samples. The optimum weld bead shape selected from the surface response graphs was effective penetration depth 1.78mm, upper bead width 5.36mm and sagging 0.39mm. And the correspond welding condition was welding current 115A and travel speed 5.7m/min. The reliability of the calculated regression equation for bead shape was varied from 90% of sagging to 98.7% of upper bead width.
Journal of Mechanical Science and Technology, 2017
We improve the performance of a low-quality GPS data on a UGV through use of multiple low-quality... more We improve the performance of a low-quality GPS data on a UGV through use of multiple low-quality GPS modules on a UGV within line of sight of the UAV. The UGV sends GPS data corrections to the UAV on the basis of the distance from the UAV to the UGV as measured by scaling of a standard image pattern stuck on the UGV. Geolocation of both UGV and UAV are performed through the use of the extended Kalman filter integrating GPS aided INS. The positioning error is reduced by a factor of 2.3 in simulation studies and a factor of 1.6 in experiment when 3 GPS sensors are used on the UGV. This is better than what one can get through pure averaging of the GPS sensors in the presence of noise in measuring the UAV-UGV distance. We show how our exploitation of geometry improves GPS sensor performance as more GPS sensors are used.
In this study, aluminum alloy sheets were welded on bead-on-plate using AC type TIG welding machi... more In this study, aluminum alloy sheets were welded on bead-on-plate using AC type TIG welding machine. Penetration depth and bead width were selected as quality factors of weld bead. Welding conditions were designed with BBD(Box-Benhken Design) method in which the input variables were welding current, arc length and travel speed. TIG welding was done on A6061 alloy sheet for the welding conditions selected by DOE at Ar shielding. The second-order regression equation was obtained using the bead shape measured from TIG welded samples. Verification test was done at the optimum welding condition determined by the surface response diagram derived from the regression equation. The optimum welding condition was welding current 110A, arc length 1.4mm and travel speed 9.6mm/s. The penetration depth and the bead width formed at the predicted optimum welding condition were 1.97±0.010mm and 4.65±0.051mm. From the result, the regression equation matched with real TIG welding in accuracy 98.5% and 96.8% for penetration depth and bead width respectively.
We show a new scheme and implementation of maritime data communication systems for GMDSS ship whi... more We show a new scheme and implementation of maritime data communication systems for GMDSS ship which performs e-Navigation and removes the functional limitation of those systems through comparing to service fee, call processing reliability, and bit rates of all of those systems within communication range at sea. We confirmed available each frequency band communication and application services at sea by experimental result with proposed new system, MF/HF band being useful to a short text message service, VHF band to 9600bps email service, Fleet Broadband Maritime Satellite system to one or more Mbps multimedia service each.
We developed an octocopter-based unmanned aerial system (UAS) to monitor remote environments. The... more We developed an octocopter-based unmanned aerial system (UAS) to monitor remote environments. The system contains various environmental monitoring sensors for measuring wind speed/direction, temperature, relative humidity, atmospheric pressure, fine dust, and multispectral and RGB data. The UAS consists of an unmanned aerial vehicle (UAV), a ground control station, and a server. We studied its electrical, mechanical, and software (SW) configurations. Specifically, we developed hardware (HW) and SW to control the yaw and gimbal pitch directions of the UAV conveying multispectral and RGB cameras. To prevent the obtained solar reflectance from affecting the multispectral and RGB data and to improve the quality of the obtained data, we maneuvered the yaw so that it would always deviate 135 • from the solar azimuth angle, with the sun at its rear. Managing the yaw direction involves controlling the UAV based on a micro air vehicle link message-based robot operating system (ROS). To safely test the UAS performance before the maiden flight in an ocean area, we first evaluated PX4 and ROS-based SW through indoor software-in-the-loop simulation (SILS) via the Gazebo tool. Subsequently, we used an F450 UAV and an actual maritime UAV to sequentially perform pre-flight and flight experiments. This paper explains the system operation scenario, UAS component, and simulation and experimental results. The results reveal that the average yaw angle error during the mission,¯ θ y,des − θ y , is approximately 8 • , and the average pitch angle of the gimbal during the mission, 50 • − θ c , is less than 5 •. INDEX TERMS Maritime environmental observation, ocean color, robot operating system, unmanned aerial system, unmanned aerial vehicle.
Styrenated phenols (SPs) are usually synthesized by the reaction of styrene and phenol under acid... more Styrenated phenols (SPs) are usually synthesized by the reaction of styrene and phenol under acid catalysts. SPs with a high content of di-styrenated phenol (DSP) can be used to prepare styrenated phenol alkoxylate (SP-A). Therefore, in this study, a scale-up process for synthesizing SPs with high DSP content which can be used for synthesis of SPA was studied. The solid catalyst used in this study was prepared by impregnation method. SO 2− 4 was impregnated on a SO 2− 4 /ZrO 2 catalyst in an aqueous 1 M H 2 SO 4 solution. The prepared catalysts were characterized by NH 3-TPD. Catalytic activity was examined by measuring the conversion of phenol and styrene in a liquid-phase batch reactor. Almost 100% conversion of both phenol and styrene over 5-SO 2− 4 /ZrO 2 catalyst was obtained at a reaction temperature of 80 C and a reaction time of 6 h. The amount of catalyst to the reactants was 2 wt%. Under the same reaction conditions, the selectivity of MSP, DSP, and TSP was 12.4%, 64.5%, and 23.1% respectively.
This study was carried out to analyze the effects of adding hydroxypropyl cellulose (HPC) on the ... more This study was carried out to analyze the effects of adding hydroxypropyl cellulose (HPC) on the rheology and dispersibility of the slurry and battery characteristics when fabricating an anode slurry containing Si alloy as the active material, a water-based binder, and deionized water as the solvent. The addition of HPC resulted in a reduction in the viscosity and excellent dispersion in the slurry. In the battery, the adhesiveness of the electrode and current collector was improved, and the initial capacity, polarization resistance, and cycling performance were improved. In addition, the expansion in thickness decreased. This was because HPC suppressed coagulation by steric hindrance and simultaneously acted as a binder by being adsorbed on the particle surfaces of the Si alloy and Ketjen black.
Small (Weinheim an der Bergstrasse, Germany), Jan 17, 2018
A feasible approach is reported to reduce the switching current and increase the nonlinearity in ... more A feasible approach is reported to reduce the switching current and increase the nonlinearity in a complementary metal-oxide-semiconductor (CMOS)-compatible Ti/SiN /p -Si memristor by simply reducing the cell size down to sub-100 nm. Even though the switching voltages gradually increase with decreasing device size, the reset current is reduced because of the reduced current overshoot effect. The scaled devices (sub-100 nm) exhibit gradual reset switching driven by the electric field, whereas that of the large devices (≥1 µm) is driven by Joule heating. For the scaled cell (60 nm), the current levels are tunable by adjusting the reset stop voltage for multilevel cells. It is revealed that the nonlinearity in the low-resistance state is attributed to Fowler-Nordheim tunneling dominating in the high-voltage regime (≥1 V) for the scaled cells. The experimental findings demonstrate that the scaled metal-nitride-silicon memristor device paves the way to realize CMOS-compatible high-densit...
Styrenated phenols (SPs) involving very small amount of unreacted phenol and high content of di-S... more Styrenated phenols (SPs) involving very small amount of unreacted phenol and high content of di-SP (DSP) were synthesized, which can be used to prepare SP alkoxylate. The solid catalyst was prepared by impregnation method. SO2-4 on SO2-4/MxOy catalyst was introduced from an aqueous 1M-H2SO4 solution. The catalysts were characterized by XRD patterns, and FT-IR spectra. The catalytic activity was examined by measuring conversion of phenol and styrene in a batch liquid-phase reactor. The concentration of phenol, styrene, and SPs were measured by GC with capillary column. The optimum synthesis conditions for concentration of sulfuric acid solution, catalyst amount of reactants, reaction temperature, and reaction time over SO2-4/ZrO2 catalyst were 15 wt%, 15 wt%, 100 °C, and 6 hr, respectively. At these conditions, conversion of both phenol and styrene were almost 100%, and the selectivity of DSP was 52.1%. On the other hand, the optimum synthesis conditions over SO2-4/TiO2 catalyst were...
Styrenated phenol was prepared by an alkylation of phenol using NiCl2 and AlCl3 supported on sili... more Styrenated phenol was prepared by an alkylation of phenol using NiCl2 and AlCl3 supported on silica gel. The conversion of phenol and styrene of alkylation reaction, and the selectivity of styrenated phenol were investigated. The Al · Ni/SiO2 Supported catalyst was used, the conversion of phenol was almost 100%. The product was in the form of a mixture of mono-styrenated phenol, di-styrenated phenol and tri-styrenated phenol. The styrenated phenol were selectivity of the varies depending on the reaction conditions.
Journal of the Korea Society of Computer and Information, 2012
The opinion of user on a certain product is expressed in positive/negative sentiments for specifi... more The opinion of user on a certain product is expressed in positive/negative sentiments for specific features of it. In some cases, they are expressed for a holistic part of homogeneous specific features, or expressed for product itself. Therefore, in the area of opinion mining, name of opinion features to be extracted are specific feature names, holonyms for theses specific features, and product names. However, when the opinion target is described with product name or holonym, sometimes it may not match feature name of opinion sentence to true opinion target intended by
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Papers by sunghun jung