• Title/Summary/Keyword: BDS

Search Result 68, Processing Time 0.078 seconds

Performance Analysis of Long Baseline Relative Positioning using Dual-frequency GPS/BDS Measurements

  • Choi, Byung-Kyu;Yoon, Ha Su;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.8 no.2
    • /
    • pp.87-94
    • /
    • 2019
  • The Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) positioning has been widely used in geodesy, surveying, and navigation fields. RTK can benefit enormously from the integration of multi-GNSS. In this study, we develop a GPS/BeiDou Navigation Satellite System (BDS) RTK integration algorithm for long baselines ranging from 128 km to 335 km in South Korea. The positioning performance with GPS/BDS RTK, GPS-only RTK, and BDS-only RTK is compared in terms of the positioning accuracy. An improvement of positioning accuracy over long baselines can be found with GPS/BDS RTK compared with that of GPS-only RTK and that of BDS-only RTK. The positioning accuracy of GPS/BDS RTK is better than 2 cm in the horizontal direction and better than 5 cm in the vertical direction. A lower Relative Dilution of Precision (RDOP) value with GPS/BDS integration can obtain a better positional precision for long baseline RTK positioning.

Apoptotic pathway of SNU-1, human gastric cancer cell line, by Bodusan (보두산에 의한 사람 위암 세포주 SNU-1의 세포사멸 경로)

  • Lee, Jae-Eun;Yun, Hyun-Joung;Lee, Young-Tae;Bae, Chang-Wook;Jeun, Hyun-Sook;Park, Sun-Dong
    • The Korea Journal of Herbology
    • /
    • v.21 no.1
    • /
    • pp.33-42
    • /
    • 2006
  • Objectives : The purpose of this study was to investigate the anticancer effects of Bodusan (BDS) on SNU-1 cells, a human gastric cancer cell line. Methods : To study the cytotoxic effect of BDS on SNU-1 cells, the cells were treated with various concentrations of BDS and then cell viability was determined by XTT reduction method and trypan blue exclusion assay. The typical signs of apoptosis, was examined by western blot analysis. BDS-induced MAPK activation was also examined by Western blot for phosphorylated ERK and p38. Results : BDS reduced proliferation of SNU-1 cells in a dose-dependent manner and decreased procaspase 3 level in a dose-dependent manner and induced the clevage of PARP at concentration > 500 ${\mu}g/ml$. BDS also triggered the mitochondrial apoptotic signaling by increasing the release of cytochrome C from mitochondria to cytosol and reducing the level of anti-apoptotic Bcl-2. BDS significantly decreased ERK phosphorylation and increased p38 phosphorylation in a dose-dependent manner. Futhermore, BDS treatment up-regulated p53 and p21waf expression in a dose-dependent manner. Conclusion : BDS-induced apoptosis is MAP kinase-dependent apoptoric pathway and arrested SNU-1 cells at the G0/G1 of cell cycle. These results suggest that BDS is potentially useful as a chemotherapeutic agent in human gastric cancer.

  • PDF

Analysis on BDS B1C Signal Interface (BDS B1C 신호 체계 분석)

  • Shin, Yerin;Yoo, Hoyoung
    • Journal of IKEEE
    • /
    • v.24 no.2
    • /
    • pp.461-467
    • /
    • 2020
  • Most civilian positioning systems in use are based on the Global Navigation Satellite System (GNSS), which receives signals from satellites and calculates the current location. After the successful establishment of GPS from the U.S., GNSS has led to promote satellite navigation systems in various countries. Recently, China has succeeded in the radical development of its own GNSS, the BeiDou Navigation Satellite System (BDS), based on its advanced IT technology and funding power. Considering that China is rapidly expanding the service area of BDS to the world, systematic research on BDS is also required in Korea. Therefore, this paper provides overall information on B1C, the open signal of BDS, so that this information can be utilized in the design of B1C signal system and BDS B1C receiver design.

BDS Statistic: Applications to Hydrologic Data (BDS 통계: 수문자료에의 응용)

  • Kim, Hyeong-Su;Gang, Du-Seon;Kim, Jong-U;Kim, Jung-Hun
    • Journal of Korea Water Resources Association
    • /
    • v.31 no.6
    • /
    • pp.769-777
    • /
    • 1998
  • In this study, various time series are analyzed to check nonlinearities of the data. The nonlinearity of a system can be investigated by testing the randomness of the time series data. To test the randomness, four nonparametric test statistics and a new test statistic, called the BDS statistic are used and the results and the results are compared. The Brock, Dechert, and Scheinkman (BDS) statistic is originated from the statistical properties of the correlation integral which is used for searching for chaos and has been shown very effective in distinguishing nonlinear structures in dynamic systems from random structures. As a result of application to linear and nonlinear models which are well known, the BDS statistic is found to be more effective than nonparametric test statistics in identifying nonlinear structure in the time series. Hydrologic time series data are fitted to ARMA type models and the statistics are applied to the residuals. The results show that the BDS statistic can distinguish chaotic nonlinearity from randomness and that the BDS statistic can also be used for verifying the validity of the fitted model.

  • PDF

Inhibitory Effect of Bodusan on $TNF-{\alpha}-induced$ Migration via Inhibition of Metalloproteinase Activity in Human Aortic Smooth Muscle Cells (보두산의 금속분해효소 활성 저해를 통한 사람 대동맥 평활근세포의 유주능 억제 효과)

  • Yun, Hyun-Jeong;Park, Sun-Dong
    • The Korea Journal of Herbology
    • /
    • v.23 no.3
    • /
    • pp.155-162
    • /
    • 2008
  • Objectives : This study was evaluated to elucidate the inhibitory potential of Bodusan (BDS) and its components, Strychnos ignatii semen (SIS) and Glycyrrhizae Radix (GR), on human aortic smooth muscle cells (HASMC) migration and production of matrix metalloproteinase (MMP)-2 and MMP-9 by $TNF-{\alpha}$ treatment. Methods : Cytotoxic activity of BDS and its components on HASMC was using 5-(3-caroboxymeth- oxyphenyl)-2H-tetra-zolium inner salt (MTS) assay. Effect of BDS, SIS and GR on $TNF-{\alpha}-induced$ HASMC migration underside of matrigel filter was stained with hematoxylin-eosin. And total number of cells that migrated to the underside of the filter was counted. MMP-2 and MMP-9 activity was evaluated by gelatin zymography assay. Results : The matrigel migration assay showed that BDS effectively inhibited the $TNF-{\alpha}-induced$ migration of HASMC. Moreover, BDS significantly inhibited MMP-9 activity. Our present study demonstrates that BDS and its components inhibits $TNF-{\alpha}-induced$ HASMC migration and MMP-9 activity. The inhibitory effect of BDS extract is more potent than that of its component herb extracts. Conclusions : These results provide evidence that BDS has multiple effects in the inhibition of HASMC migration and may offer a therapeutic approach to block HASMC migration.

  • PDF

GEO-KOMPSAT-2A AMI Best Detector Select Map Evaluation and Update (천리안위성2A호 기상탑재체 Best Detector Select 맵 평가 및 업데이트)

  • Jin, Kyoungwook;Lee, Sang-Cherl;Lee, Jung-Hyun
    • Korean Journal of Remote Sensing
    • /
    • v.37 no.2
    • /
    • pp.359-365
    • /
    • 2021
  • GEO-KOMPSAT-2A (GK2A) AMI (Advanced Meteorological Imager) Best Detector Select (BDS) map is pre-determined and uploaded before the satellite launch. After the launch, there is some possibility of a detector performance change driven by an abrupt temperature variation and thus the status of BDS map needs to be evaluated and updated if necessary. To investigate performance of entire elements of the detectors, AMI BDS analyses were conducted based on a technical note provided from the AMI vendor (L3HARRIS). The concept of the BDS analysis is to investigate the stability of signals from detectors while they are staring at targets (deep space and internal calibration target). For this purpose, Long Time Series (LTS) and Output Voltage vs. Bias Voltage (V-V) methods are used. The LTS for 30 secs and the V-V for two secs are spanned respectively for looking at the targets to compute noise components of detectors. To get the necessary data sets, these activities were conducted during the In-Orbit Test (IOT) period since a normal operation of AMI is stopped and special mission plans are commanded. With collected data sets during the GK2A IOT, AMI BDS map was intensively examined. It was found that about 1% of entire detector elements, which were evaluated at the ground test, showed characteristic changes and those degraded elements are replaced by alternative best ones. The stripping effects on AMI raw images due to the BDS problem were clearly removed when the new BDS map was applied.

Performance Analysis of BDSBAS and MSAS in Korea

  • Noh, Jae Hee;Lim, Deok Won;Lee, Ju Hyun;Jo, Gwang Hee;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.9 no.3
    • /
    • pp.249-259
    • /
    • 2020
  • China has deployed BDS along with the service of SBAS by 2020. Currently, the correction information for testing BDSBAS is provided through the BDS B1I signal. Many research on SBAS other than BDSBAS has been conducted in Korea. However, studies on BDSBAS are insufficient although Korea is included in both the coverage area of MSAS and BDSBAS. Therefore, it is necessary to continuously analyze the performance of MSAS and BDSBAS. In this paper, the performance of MSAS and BDSBAS in Korea, China, and Japan is analyzed in the aspect of positioning accuracy using the GNSS RINEX data provided by IGS. A Software platform is designed to analyze the performance of GPS-only, BDS-only, GPS/MSAS and BDS/BDSBAS. From the result, it can be concluded that the accuracy enhancement can be hardly seen when using the correction information of MSAS and BDSBAS in Korea

Accuracy Assessment of IGSO and GEO of BDS and QZSS Broadcast Ephemeris using MGEX Products

  • Son, Eunseong;Choi, Heonho;Joo, Jungmin;Heo, Moon Beom
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.9 no.4
    • /
    • pp.347-356
    • /
    • 2020
  • In this study, Inclined Geosynchronous Orbit (IGSO) and Geostationary Orbit (GEO) of BeiDou System (BDS) and Quasi Zenith Satellite System (QZSS) satellites positions and clock errors calculated by broadcast ephemeris and compared with Multi-GNSS Experiment (MGEX) products provided by five Analysis Centers (ACs). Root Mean Square Errors (RMSE) calculated for satellite position error. The IGSO results showed that 1.82 m, 0.91 m, 1.28 m in BDS and 1.34 m 0.36 m 0.49 m in QZSS and the GEO results showed that 2.85 m, 6.34 m, 6.42 m in BDS and 0.47 m, 4.79 m, 5.82 m in QZSS in the direction of radial, along-track and cross-track respectively. RMS calculated for satellite clock error. The IGSO result showed that 2.08 ns and 1.24 ns and the GEO result showed that 1.28 ns and 1.12 ns in BDS and QZSS respectively.

Performance Analysis of GPS/BDS Integrated Precise Positioning System Considering Visibility in Urban Environments

  • Noh, Jae Hee;Lee, Sun Yong;Lim, Deok Won;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.8 no.1
    • /
    • pp.31-40
    • /
    • 2019
  • In recent years, Intelligent Transport Systems (ITS) and Autonomous Vehicle Technology have actively studied around the world. In order to achieve the purpose of Advanced Driver Assistance System (ADAS) and Autonomous Vehicle Technology, it must be obtained accurate and reliable positioning. However, the problem of positioning in the urban area is a low position accuracy caused by the reduction of the number of visible satellites due to high buildings. In this paper, we analyzed the availability of precise positioning system in urban area are using GPS/BDS integrated system. For this study, GPS and BDS satellite signals were collected using two low-cost receivers in the open sky and a designed software based platform for precise positioning performance analysis. And we analyzed the precise positioning performance by changing the mask angle considering the urban area. From the results, it can be confirmed that the performance of precise positioning of GPS only and BDS only decrease in the environment where mask angle is $40^{\circ}$ to $45^{\circ}$, however, GPS/BDS integrated system maintains high performance of precise positioning.

Detecting Nonlinearity of Hydrologic Time Series by BDS Statistic and DVS Algorithm (BDS 통계와 DVS 알고리즘을 이용한 수문시계열의 비선형성 분석)

  • Choi, Kang Soo;Kyoung, Min Soo;Kim, Soo Jun;Kim, Hung Soo
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.2B
    • /
    • pp.163-171
    • /
    • 2009
  • Classical linear models have been generally used to analyze and forecast hydrologic time series. However, there is growing evidence of nonlinear structure in natural phenomena and hydrologic time series associated with their patterns and fluctuations. Therefore, the classical linear techniques for time series analysis and forecasting may not be appropriate for nonlinear processes. In recent, the BDS (Brock-Dechert-Scheinkman) statistic instead of conventional techniques has been used for detecting nonlinearity of time series. The BDS statistic was derived from the statistical properties of the correlation integral which is used to analyze chaotic system and has been effectively used for distinguishing nonlinear structure in dynamic system from random structures. DVS (Deterministic Versus Stochastic) algorithm has been used for detecting chaos and stochastic systems and for forecasting of chaotic system. This study showed the DVS algorithm can be also used for detecting nonlinearity of the time series. In this study, the stochastic and hydrologic time series are analyzed to detect their nonlinearity. The linear and nonlinear stochastic time series generated from ARMA and TAR (Threshold Auto Regressive) models, a daily streamflow at St. Johns river near Cocoa, Florida, USA and Great Salt Lake Volume (GSL) data, Utah, USA are analyzed, daily inflow series of Soyang dam and the results are compared. The results showed the BDS statistic is a powerful tool for distinguishing between linearity and nonlinearity of the time series and DVS plot can be also effectively used for distinguishing the nonlinearity of the time series.

  • PDF