• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1190-1195
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• 2003

In this paper, it is shown how a robot with n passive trailers can be controlled in backward direction. When driving backward direction, a kinematic model of the system is represented highly nonlinear equations. The problem is formulated as a trajectory following problem, rather than control of independent generalized coordinates. Also, the state and input saturation problems are formulated as a trajectory generation problem. The trajectory is traced by a rear hinge point of the last trailer, and reference trajectories include line segments, circular shapes and rectangular turns. Experimental verifications were carried out with the PSR-2(public service robot $2^{nd}$ version) with three passive trailers. Experimental result showed that the backward motion control can be successfully carried out using the proposed control scheme.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.669-677
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• 2002

This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.821-830
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• 2006

To identify the effect of local air pollutants on the $PM_{2.5}$ level at Gosan, $PM_{2.5}$ composition data, continuous $O_3,\;NO_x,\;SO_2,\;CO$ data, VOCs data, surface wind characteristics, and backward trajectory analysis results were analyzed for the measurements in March 2000 during which high concentrations of mass and anthropogenic ionic species were reported. It was found that the combination of surface wind and continuous gaseous species data can help to identify local effect in Jeju Island. Even in a high $PM_{2.5}$ level case mainly affected by long range transport from China, it was Identified that local effects were also significant for both the duration and pollutants' levels.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.507-517
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• 2002

Cheeka Peak is a unique site for monitoring the background chemistry and aerosol contents of pristine marine air at mid-latitude. During long-range onshore winds that occur frequently throughout the year, it is predicted to have the cleanest air in the northern hemisphere. Measurements of CO and O$_3$were conducted at Cheeka Peak Observatory(CPO) on the northwestern tip of Washington state, USA during March 6 ∼May 29, 2001. The data have been segregated to quantify the mixing ratio of these species in the Pacific marine atmosphere. Also the marine air masses were further classified into four categories based on 10-day backward isentropic trajectories; high, mid, and low latitude and those which had crossed over the Asian industrial region. The diurnal variation of CO and O$_3$at CPO showed a similar to tendency of background measurement site. When marine air mass flowed to CPO, CO concentration was lower and O$_3$was similar or higher than those of total data. The westerly flow from ocean, not easterly from continent occurred the high concentration of CO and O$_3$at CPO. Using the trajectory segregation of marine air mass, the comparison of concentration according to latitude calculated. the CO concentration of Asian trajectory was lower than other latitudes, O$_3$concentration was higher.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.612-624
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• 2007

The real-time monitoring of radon ($^{222}Rn$) concentrations has been carried out to evaluate its ambient background concentration levels in Gosan site, Jeju Island between January 2001 and December 2004. In addition, the atmospheric TSP aerosols have been sampled, and their ionic and metallic components were analyzed to understand the characteristics of air pollution. The mean concentration of radon was $3,121{\pm}1,627\;mBq/m^3$, and the seasonal mean concentrations for spring, summer, fall and winter seasons were 2,898, 2,398, 3,571 and $3,646\;mBq/m^3$, respectively, The hourly concentrations have shown the highest value at 7 a.m. and the lowest value at 2 p.m. From the backward trajectory analyses, the radon concentrations have increased, when the air parcels were moved from the Chinese continent to Jeju area. On the other hand, they have decreased, when the air parcels from the North Pacific Ocean. In the analytical results of ionic species and metal elements of TSP aerosols, the concentrations of $nss-{SO_4}^{2-}$ and S were higher in June and March. Meanwhile, the concentrations of other anthropogenic species as well as soil components were mostly higher in March and April. On the basis of factor analysis, the TSP aerosols at Gosan area were largely influenced by soil sources, followed by anthropogenic sources and marine sources. From the result of backward trajectory analyses, the concentrations of $nss-{SO_4}^{2-},\;{NO_3}^-$, Al and Ca were mostly higher, when the air parcels moved from Chinese continent to Jeju area. On the other hand, their concentrations were lower, when the air parcels drifted from the North Pacific Ocean.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.175-182
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• 1994

Backward trajectory analysis was carried out for 41 cases at 850 hPa level and 47 cases at 700 hPa level during the period from May 1992 to August 1993 in order to understand the impact of long-range transported pollutants from the neighboring countries on the distribution pattern of acid rain in Korea. The occurrence frequencies of acid rain were also investigated using the rainwater data observed at 5 stations in the central part of Korea, Kangwha, Seoul, Yangpyong, Hongchon, and Inje. The trajectory analysis showed that westerlies were dominant on 700 hPa level and southwesterlies on 850 hPa level in Korea. The pH values were also often lower when the trajectory was stagnant in the upper air over Korea. However, pH values were normally higher in all directions of flows during the Yellow Sand Period due to the increase of Positive ion components such as $Ca^{+2}$. The pH values were also normally higher when air flows from north or northeast.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.415-426
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• 2023

In this study, the horizontal and vertical structure of wind speed and wind direction were analyzed at the origin of migratory insect pests in China. Wind rose analysis was carried out using the Land-Atmosphere Modeling Package (LAMP) - WRF data, which has the spatiotemporal resolution of about 20 km and 1 hour intervals. Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) was employed for backward trajectory analysis between South Korea and Southeastern China with Global Data Assimilation System (GDAS). The research interest date is July 16, when rice planthopper and leafhopper were observed at the same time. In order to examine where a jet stream occurs in the vertical in source regions and South Korea during the period (July 8 to July 17 in 2021), three-dimensional wind information was extracted and analyzed using the east-west, north-south, and vertical component wind data of the LAM P. The vertical distribution of wind showed that the wind changed in favor of the inflow of migratory insect pests during the period. As a result of analyzing the wind rose, about 30% or more of the wind at a point close to South Korea was classified into the low-level jet stream. In addition, majority of the wind directions for the low-level jet streams (rather than high-level jet streams) at the five origin sites were heading toward South Korea and even Japan, and this was supported by the HYSPLIT-based backward trajectory analysis.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.815-824
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• 2012

The purpose of this study was to analyze the meteorological characteristics of wintertime high PM10 concentration episodes in Busan. $PM_{10}$ concentration has been reduced for the past four years and recorded near or exceeded 100 ${\mu}g/m^3$ (national standard of $PM_{10}$). High concentration episodes in Busan were 6 case, $PM_{2.5}/PM_{10}$ ratio was 0.36~0.39(mean 0.55). High $PM_{10}$ concentration occurred during higher air temperature, more solar radiation and sunshine, lower relative humidity, and smaller cloud amount. Synoptically, it also occurred when Busan was in the center or the edge of anticyclone and when sea breeze intruded. An analysis of upper air sounding showed that high $PM_{10}$ concentration occurred when surface inversion layer and upper subsidence inversion layer existed, and when boundary layer depth and vertical mixing coefficient were low. An analysis of backward trajectory of air mass showed that high $PM_{10}$ concentration was largely affected by long range transport considering that it occurs when air mass is intruded from China.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.6
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• pp.439-450
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• 1997

Atmospheric fine particles $(PM_{2.5})$ were collected at the background sites, Kangwha, Taean, and Kosan and characterized to understand their behaviors at the sites. Daily samples of $PM_{2.5}$ mass were measured and ionic species, carbonaceous species, and gaseous species were analyzed. Four-day backward trajectory analysis was also carried out. The mean concentrations of anthropogenic species were highest at Kangwha among three sites, while contributions from sea salts wree highest at Taean during the measurement period due to higher wind speed at Taean. Major chemical components in fine particles were sulfate, organic carbon, nitrate, and ammoniu. Most of the non-sea-salt (nss) sulfates in $PM_{2.5}$ might be present as ammonium sulfates at these sites. Most air parcels arriving at Kangwha and Taean were from northern China. Therefore, both sites were thought to be affected by the same air parcel. At Kosan, during the measurement period, air parcels were from either northern China or sourthern China. The nss sulfate concentration in the air parcels from southern China was higher, while the nss calcium, nitrate, and ammonium concentrations were higher when the air parcels were from northern China.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.5
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• pp.361-369
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• 1997

In order to investigate the abundance and transboundary fluxes of air pollutants over the Yellow Sea, airborne measurements were made aboard the SF-600 aircraft (Pan-Asia Engineering) in March, 1996. The data presented in this paper are preliminary results and airborne experiment will be carried out until 1999. The vertical profile of relevant meteorological parameters such as temperature, water vapor, wind direction and wind speed were also observed at Taean. Mixing layer height was about 1000~1100m during the flights. The SO$_2$ and NO$_{x}$ concentrations were 3~6 ppb and 5~7 ppb below 1000 m, within 1 ppb and 3~5 ppb at 1000~2000m, respectively. Backward trajectory analyses were also carried out. A mathematical method by Lelieveld et al.(1989) was used to estimate the flux of air pollutants through the planetary boundary layer of Yellow Sea area. Transboundary fluxes were calculated using the measurement results with respect to the pollutants concentration, depth of the planetary boundary layer, wind speed and wind direction. The estimated transboundary flux of SO$_2$through the western boundary of Korea was about 39~42 tons/hour.r.