Publications by authors named "Xiaoxiong Xiong"

In this paper, a new system entropy measure is used to optimize the routing algorithm in power consumption. We introduce the system entropy measure into the problem of industrial wireless sensor networks (iWSNs) routing and propose a high-performance routing algorithm guided by the system entropy measure (rSEM). Based on the cluster iWSNs architecture, the rSEM selects the cluster heads and cluster member nodes successively, according to the system entropy measure, and constructs the iWSNs with the minimum system entropy.

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Deep convective clouds (DCC) are identified by using a combination of brightness temperature (BT) and visible reflectance thresholds. Moreover, it is common practice to use daytime DCC measurements for the calibration assessment of reflective solar and longwave infrared (LWIR) bands. The DCC cold core is suitable for the MODIS Thermal Emissive Bands (TEB) calibration assessment; more specifically, for the offset effect in the quadratic calibration function.

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  • GOES-16/ABI and Himawari-8/AHI are advanced geostationary satellites with improved infrared channels and a spatial resolution of 2 km, enhancing data quality over older models.
  • Both satellites utilize similar calibration methods with an onboard blackbody and space look, facilitating effective inter-comparison for calibration and product quality improvements.
  • The study conducted found that GOES-16 is generally more precise than Himawari-8 in thermal emissive bands, with differences in temperature measurements mostly within 0.8K, confirming consistent ABI performance pre- and post-relocation.
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  • The VIIRS on the NOAA-20 satellite performs regular radiometric calibration of its reflective solar bands using an onboard sunlit solar diffuser to ensure accurate data collection.
  • The onboard solar diffuser stability monitor observes changes in the solar diffuser's reflectance, indicated by the -factor, which was initially found to have significant errors due to prelaunch calibration data.
  • After conducting 15 yaw maneuvers to adjust screen functions, additional on-orbit calibration data refined the -factor measurements, resulting in smoother data and improved calibration accuracy.
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  • The Visible Infrared Imaging Radiometer Suite (VIIRS) on the NOAA-20 satellite, launched on November 18, 2017, features 22 spectral bands, significantly increasing its sensitivity to light polarization compared to its predecessor.
  • Prelaunch tests showed polarization sensitivities, particularly in short wavelength bands M1-M4, exceeded specifications, causing issues like striping in images and increased data uncertainties.
  • The paper discusses the proposed algorithms to correct these polarization effects for ocean imagery, successfully reducing errors and artifacts in the satellite's environmental data records by adjusting for the impacts of atmospheric light scattering.
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The visible infrared imaging radiometer suite on the Suomi National Polar-orbiting Partnership satellite calibrates its reflective solar bands through observations of a sunlit solar diffuser (SD) panel. Sunlight passes through a perforated plate, referred to as the SD screen, before reaching the SD. It is critical to know whether the SD screen transmittance measured prelaunch is accurate.

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  • - The MODIS instruments on Terra and Aqua satellites use on-board calibrators (solar diffuser, blackbody, space view) for radiometric calibration while capturing images across 36 spectral bands using a whisk-broom scanning technique.
  • - A co-registration mechanism aligns images of targets based on how the scan mirror operates, but this method shows inaccuracies for "near field" targets, especially when dealing with the on-board calibrators.
  • - The study identifies the misregistration as being caused by the scan mirror's position relative to the telescope's focus, affecting the calibration accuracy, particularly improving the detector gain coefficients for specific bands on Aqua MODIS by up to 1.5%.
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The inter-comparison of MODIS reflective solar bands onboard Aqua and Terra is very important for assessment of each instrument's calibration. One of the limitations is the lack of simultaneous nadir overpasses. Their measurements over a selected Earth view target have significant differences in solar and view angles, which magnify the effects of atmospheric scattering and Bidirectional Reflectance Distribution Function (BRDF).

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The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides ±56.28° scans of the Earth view.

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Polarization sensitivity is a critical property that must be characterized for spaceborne remote sensing instruments designed to measure reflected solar radiation. Broadband testing of the first Joint Polar-orbiting Satellite System (JPSS-1) Visible Infrared Imaging Radiometer Suite (VIIRS) showed unexpectedly large polarization sensitivities for the bluest bands on VIIRS (centered between 400 and 600 nm). Subsequent ray trace modeling indicated that large diattenuation on the edges of the bandpass for these spectral bands was the driver behind these large sensitivities.

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Article Synopsis
  • The MODerate-resolution Imaging Spectroradiometer (MODIS) is a key Earth observation tool on the Terra and Aqua satellites, successfully operating beyond their initial design lifespans.
  • MODIS has a high duty cycle, allowing it to capture data from almost the entire Earth in under 2 days, utilizing specialized thermal bands for detailed measurements.
  • The paper evaluates calibration and noise performance using various techniques, including measuring temperature stability and noise metrics, to ensure accurate data collection from the sensor's thermal emissive bands.
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The VIIRS instrument on board the S-NPP spacecraft has successfully operated for more than four years since its launch in October, 2011. Many VIIRS environmental data records (EDR) have been continuously generated from its sensor data records (SDR) with improved quality, enabling a wide range of applications in support of users in both the operational and research communities. This paper provides a brief review of sensor on-orbit calibration methodologies for both the reflective solar bands (RSB) and the thermal emissive bands (TEB) and an overall assessment of their on-orbit radiometric performance using measurements from instrument on-board calibrators (OBC) as well as regularly scheduled lunar observations.

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Observations of the Moon provide a primary technique for the on-orbit cross calibration of Earth remote sensing instruments. Monthly lunar observations are major components of the on-orbit calibration strategies of SeaWiFS and MODIS. SeaWiFS has collected more than 132 low phase angle and 59 high phase angle lunar observations over 12 years, Terra MODIS has collected more than 82 scheduled and 297 unscheduled lunar observations over nine years, and Aqua MODIS has collected more than 61 scheduled and 171 unscheduled lunar observations over seven years.

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Ocean-color applications require maximum uncertainties in blue-wavelength water-leaving radiances in oligotrophic ocean of approximately 5%. Water-leaving radiances from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite, however, exhibit temporal drift of the order of 15% as well as sensor changes in response versus scan and polarization sensitivity, which cannot be tracked by onboard calibrators. This paper introduces an instrument characterization approach that uses Earth-view data as a calibration source.

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The combination of carboplatin and paclitaxel is widely used to treat multiple solid tumors including ovarian, lung and breast cancer. Usually these drugs are given simultaneously with little regard to the importance of scheduling to obtain a maximal response. To investigate the importance of sequencing, the human breast Bcap37 and ovarian OV2008 cancer cell lines were exposed to carboplatin and paclitaxel in three different sequences: (1) pretreatment with paclitaxel followed by carboplatin, (2) pretreatment of carboplatin followed by paclitaxel and (3) simultaneous treatment with these two agents.

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Paclitaxel, the first member of taxanes, is one of the most active chemotherapeutic agents developed in the last decade for the treatment of advanced breast cancer and many other types of solid tumors. The promising clinical activity of paclitaxel has also promoted considerable interest in combining this drug with other anti-tumor agents. In this study, we assessed the cytotoxic interaction between paclitaxel and gemcitabine administered at various schedules to human breast and ovarian cancer cells.

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Objective: To investigate whether telomerase activity, human telomerase RNA (HTR) and human telomerase reverse transcriptase (HTERT) expression were associated with tumor development in lung cancer and whether telomerase is regulated at gene level or transcriptional level.

Methods: Expression of HTR and HTERT was detected by reverse transcription-polymerase chain reaction (RT-PCR) in 68 human lung cancer and in 68 adjacent-neoplatic lung tissues. And telomerase activity was examined by a quantitative telomeric repeat amplification protocol (TRAP).

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Article Synopsis
  • The study examines the link between telomerase activity and the expression of its components (hTR and hTERT) in lung cancer tissues compared to adjacent non-cancerous tissues.
  • In 68 lung cancer samples, telomerase activity was found in 79.4% of cases, while hTR and hTERT showed high expression rates (98.5% and 91.2% respectively), contrastingly, hTERT was rarely found in normal tissues (10.3%).
  • Results indicate that hTERT expression is closely tied to telomerase activity, suggesting that telomerase potentially contributes to lung cancer development and might be regulated at the
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