43 research outputs found

    Efficient Simulation for Fixed-Receiver Bistatic SAR with Time and Frequency Synchronization Errors

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    Time and frequency synchronization is the key technique of bistatic synthetic aperture radar (BiSAR) system, and raw data simulation is an effective tool for verifying the time and frequency synchronization techniques. According to the two-dimensional (2-D) frequency spectrum of fixed-receiver BiSAR with time and frequency synchronization errors, a rapid raw data simulation method is proposed in this paper. Through 2-D inverse Stolt transform in 2-D frequency domain and phase compensation in Range-Doppler frequency domain, this method can realize two-dimensional spatial variation simulation for fixed-receiver BiSAR with time and frequency synchronization errors in a reasonable time consumption. Then the simulation efficiency of scene raw data can be significantly improved. Simulation results of point targets and extended scene are presented to validate the feasibility and efficiency of the proposed simulation method

    Future growth pattern projections under shared socioeconomic pathways: a municipal city bottom-up aggregated study based on a localised scenario and population projections for China

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    Precise multi-scenario projections of future economic outputs based on localised interpretations of global scenarios and major growth drivers are important for understanding long-term economic changes. However, few studies have focussed on localised interpretations, and many assume regional uniformity or use key parameters that are recursive or extrapolated by mathematical methods. This study provides a more intuitive and robust economic framework for projecting regional economic growth based on a neoclassical economic model and shared socioeconomic pathways (SSPs) scenarios. A non-uniform version of SSP2 (the middle-of-the-road scenario) was developed, and more detailed population projections for China were adopted using municipal-level data for 340 districts and parameter settings based on China’s recent development. The results show that China’s GDP will vary substantially across SSPs by 2050. Per capita GDP ranges from 19,300 USD under SSP3 (fragmentation) to 41,100 USD under SSP5 (conventional development). Per capita GDP under SSP1 (sustainability) is slightly higher than under SSP2, but lower on average than under SSP5. However, SSP1 is a better choice overall because environmental quality and equity are higher. Per capita GDP growth will generally be higher in relatively low-income regions by 2050, and the upper-middle-income provinces will become China’s new engine for economic growth

    Spatial decorrelation in GNSS-based SAR coherent change detection

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    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Temporal decorrelation model for the bistatic SAR interferometry

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    The Effect of Notch Filter on RFI Suppression

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    Spatial Decorrelation in GNSS-Based SAR Coherent Change Detection

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