• Title, Summary, Keyword: Backward trajectory

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Backward motion control of a mobile robot with n passive trailers

  • Park, Myoung-Kuk;Chung, Woo-Jin;Kim, Mun-Sang;Song, Jae-Bok
    • 제어로봇시스템학회:학술대회논문집
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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.

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Role of Transport on Aerosol Concentration at Crater Lake, Oregon USA (미국 오레곤주 Crater Lake의 에어로졸 농도에 미치는 수송의 역할)

  • 전병일
    • 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.

The Effect of Local Air Pollutants in a Background Area: Measurements at Gosan in March 2000 (배경지역에서의 국지오염원의 영향: 2000년 3월 고산 측정결과)

  • Kim, N.K.;Kim, Y.P.
    • 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.

Characteristics of Springtime CO and O3 according to Transport at Cheeka Peak Observatory(CPO), Northwest of USA (미국 서북부 Cheeka Peak에서의 수송에 따른 봄철 CO와 O3의 특성)

  • 전병일
    • 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.

Radon and TSP Concentrations in the Ambient Air of Gosan Area, Jeiu Island between 2001 and 2004 (제주도 고산지역의 라돈 및 TSP 에어로졸 농도 특성: 2001~2004년 측정)

  • Kang, Chang-Hee;Ko, Hee-Jung;Zahorowski, Wlodek
    • 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.

Trajectory Analysis on Acid Rain Observed in the Central Part of Korea During 1992 to 1993 (한반도 중부지방에서 관측된 1992-1993년 산성비의 특성과 공기 이동 경로 분석)

  • 전영신;조하만;권원태
    • 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.

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Characteristics of suspended particulate for Yellow sand of January, 1999 in Busan (1999년 1월의 황사 발생시 부산지역의 부유분진 특성)

  • 전병일;박재림;박종길
    • Journal of Environmental Science International
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    • v.11 no.10
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    • pp.1081-1087
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    • 2002
  • This study was performed to research the characteristics of suspended particulate for Yellow Sand of January, 1999 in Busan. Yellow Sand frequency during 13 years(1988~2000) in Busan showed maximum in April(57%), next to March(21%), May(16%). According to result of 850hPa weather map and backward isentropic trajectory, this event originated from the Gobi Desert and the Loess Plateau of China. And three mode was found in time series of TSP and PM10 concentration, primary peak showed the maximum hourly concentration at ali station. Gamjeondong as industrial site showed the highest TSP concentration and also had the longest high concentration($geq700\mu\textrm{g}/m^3$). In PM10, concentration of primary peak showed maximum value at Yeonsandong, maximum concentration of secondary and third peak was Deokcheondong. Lasted time from primary peak to secondary peak was about 30 hours, between secondary peak and third peak was 18 hours in Busan, The traveling time between occurrence of Yellow Sand the finding of it was 8~9 hours in Busan and 4~5 hours in central area.

Aircraft Measurement of SO$_2$, NO$_{x}$ over Yellow Sea Area (항공기를 이용한 서해안에서의 SO$_2$ 및 NO$_{x}$의 측정)

  • 김병곤;차준석;한진석;박일수;김정수;나진균;최덕일;안준영;강창국
    • 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.

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Characteristics of $PM_{2.5}$ Particles Measured in the Background Sites of Korea (우리나라 청정 지역에서 측정한 $PM_{2.5}$ 입자의 특성)

  • 이종훈;김용표;문길주;김희강;정용승;이종범
    • 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.

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Meteorological Characteristics of the Wintertime High PM10 Concentration Episodes in Busan (부산지역 겨울철 고농도 미세먼지 발생일의 기상학적 특성)

  • Jeon, Byung-Il
    • 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.