In this paper, a joint beam selection and power allocation (JBSPA) strategy is developed for multiple target tracking in netted colocated multiple-input multiple-output radar system. Each radar in ...this network adopts a multibeam working mode, in which multiple simultaneous transmit beams are synthesized. The basis of the JBSPA strategy is to use the optimization technique to control the limited beam and power resource of each radar in order to achieve accurate target state estimation. The Bayesian Cramér-Rao lower bound is derived, normalized, and subsequently utilized, as the optimization criterion for the JBSPA strategy. The resulting optimization problem consists of two adaptable parameters, one for beam selection and the other for power allocation. By introducing an auxiliary vector, a fast two-step solution technique is presented to jointly decide the number of beams generated by each radar, as well as the assignment and transmit power of each beam, subject to some resource constraints. Simulation results verify the superiority of the proposed JBSPA algorithm, in terms of the worst-case tracking accuracy of the multiple targets.
Motion Compensation for UAV SAR Based on Raw Radar Data Mengdao Xing, Mengdao Xing; Xiuwei Jiang, Xiuwei Jiang; Renbiao Wu, Renbiao Wu ...
IEEE transactions on geoscience and remote sensing,
08/2009, Letnik:
47, Številka:
8
Journal Article
Recenzirano
Unmanned aerial vehicle (UAV) synthetic aperture radar (SAR) is very important for battlefield awareness. For SAR systems mounted on a UAV, the motion errors can be considerably high due to ...atmospheric turbulence and aircraft properties, such as its small size, which makes motion compensation (MOCO) in UAV SAR more urgent than other SAR systems. In this paper, based on 3-D motion error analysis, a novel 3-D MOCO method is proposed. The main idea is to extract necessary motion parameters, i.e., forward velocity and displacement in line-of-sight direction, from radar raw data, based on an instantaneous Doppler rate estimate. Experimental results show that the proposed method is suitable for low- or medium-altitude UAV SAR systems equipped with a low-accuracy inertial navigation system.
Patients with locoregionally advanced nasopharyngeal carcinoma have a high risk of disease relapse, despite a high proportion of patients attaining complete clinical remission after receiving ...standard-of-care treatment (ie, definitive concurrent chemoradiotherapy with or without induction chemotherapy). Additional adjuvant therapies are needed to further reduce the risk of recurrence and death. However, the benefit of adjuvant chemotherapy for nasopharyngeal carcinoma remains controversial, highlighting the need for more effective adjuvant treatment options.
This multicentre, open-label, parallel-group, randomised, controlled, phase 3 trial was done at 14 hospitals in China. Patients (aged 18–65 years) with histologically confirmed, high-risk locoregionally advanced nasopharyngeal carcinoma (stage III–IVA, excluding T3–4N0 and T3N1 disease), no locoregional disease or distant metastasis after definitive chemoradiotherapy, an Eastern Cooperative Oncology Group performance status of 0 or 1, sufficient haematological, renal, and hepatic function, and who had received their final radiotherapy dose 12–16 weeks before randomisation, were randomly assigned (1:1) to receive either oral metronomic capecitabine (650 mg/m2 body surface area twice daily for 1 year; metronomic capecitabine group) or observation (standard therapy group). Randomisation was done with a computer-generated sequence (block size of four), stratified by trial centre and receipt of induction chemotherapy (yes or no). The primary endpoint was failure-free survival, defined as the time from randomisation to disease recurrence (distant metastasis or locoregional recurrence) or death due to any cause, in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of capecitabine or who had commenced observation. This trial is registered with ClinicalTrials.gov, NCT02958111.
Between Jan 25, 2017, and Oct 25, 2018, 675 patients were screened, of whom 406 were enrolled and randomly assigned to the metronomic capecitabine group (n=204) or to the standard therapy group (n=202). After a median follow-up of 38 months (IQR 33–42), there were 29 (14%) events of recurrence or death in the metronomic capecitabine group and 53 (26%) events of recurrence or death in the standard therapy group. Failure-free survival at 3 years was significantly higher in the metronomic capecitabine group (85·3% 95% CI 80·4–90·6) than in the standard therapy group (75·7% 69·9–81·9), with a stratified hazard ratio of 0·50 (95% CI 0·32–0·79; p=0·0023). Grade 3 adverse events were reported in 35 (17%) of 201 patients in the metronomic capecitabine group and in 11 (6%) of 200 patients in the standard therapy group; hand-foot syndrome was the most common adverse event related to capecitabine (18 9% patients had grade 3 hand-foot syndrome). One (<1%) patient in the metronomic capecitabine group had grade 4 neutropenia. No treatment-related deaths were reported in either group.
The addition of metronomic adjuvant capecitabine to chemoradiotherapy significantly improved failure-free survival in patients with high-risk locoregionally advanced nasopharyngeal carcinoma, with a manageable safety profile. These results support a potential role for metronomic chemotherapy as an adjuvant therapy in the treatment of nasopharyngeal carcinoma.
The National Natural Science Foundation of China, the Key-Area Research and Development Program of Guangdong Province, the Natural Science Foundation of Guangdong Province, the Innovation Team Development Plan of the Ministry of Education, and the Overseas Expertise Introduction Project for Discipline Innovation.
For the Chinese translation of the abstract see Supplementary Materials section.
Statistical modeling for radar high-resolution range profile (HRRP) is a challenging task in radar HRRP statistical recognition. Theoretical analysis and experimental results show that elements in an ...HRRP sample are statistically correlated and non-Gaussian distributed. First, this paper introduces three joint-Gaussian models, i.e., subspace approximation model, probability principal components analysis (PPCA) model and factor analysis (FA) model, into radar HRRP statistical recognition. Due to the experimental results, we can have the conclusion that the jointly non-Gaussian distributed HRRP samples approximately follow the joint-Gaussian distribution described by FA model. Therefore, we can apply FA model to radar HRRP statistical recognition rather than a joint-Gaussian mixture model, e.g., PPCA mixture model or FA mixture model, which is a more accurate choice for modeling non-Gaussian distributed correlations in multidimensional data but with high learning complexity and large computation burden, and the difficulty in the statistical modeling for HRRP samples is largely reduced. Second, this paper concerns model selection of FA model in radar HRRP statistical recognition, in which there are two issues, i.e., the partition of target-aspect frames and the determination of the number of factors in each frame. Based on the Akaike information criterion (AIC) and the Bayes' information criterion (BIC), an iterated algorithm for model selection is proposed in this paper, which can automatically give the optimal aspect-frame boundaries and determine the optimal number of factors in each aspect-frame. The recognition experiments based on measured data show that the proposed adaptive partition approach can further improve the recognition performance with higher recognition efficiency.
In the natural environment, interactions between species are a common natural phenomena. The mechanisms of interaction between different species are mainly studied using genomic, transcriptomic, ...proteomic, and metabolomic techniques. Metabolomics is a crucial part of system biology and is based on precision instrument analysis. In the last decade, the emerging field of metabolomics has received extensive attention. Metabolomics not only provides a qualitative and quantitative method for studying the mechanisms of interactions between different species, but also helps clarify the mechanisms of defense between the host and pathogen, and to explore new metabolites with various biological activities. This review focuses on the methods and progress of interspecies metabolomics. Additionally, the prospects and challenges of interspecies metabolomics are discussed.
Summary Background The value of adding cisplatin, fluorouracil, and docetaxel (TPF) induction chemotherapy to concurrent chemoradiotherapy in locoregionally advanced nasopharyngeal carcinoma is ...unclear. We aimed to compare TPF induction chemotherapy plus concurrent chemoradiotherapy with concurrent chemoradiotherapy alone in a suitably powered trial. Methods We did an open-label, phase 3, multicentre, randomised controlled trial at ten institutions in China. Patients with previously untreated, stage III–IVB (except T3-4N0) nasopharyngeal carcinoma, aged 18–59 years without severe comorbidities were enrolled. Eligible patients were randomly assigned (1:1) to receive induction chemotherapy plus concurrent chemoradiotherapy or concurrent chemoradiotherapy alone (three cycles of 100 mg/m2 cisplatin every 3 weeks, concurrently with intensity-modulated radiotherapy). Induction chemotherapy was three cycles of intravenous docetaxel (60 mg/m2 on day 1), intravenous cisplatin (60 mg/m2 on day 1), and continuous intravenous fluorouracil (600 mg/m2 per day from day 1 to day 5) every 3 weeks before concurrent chemoradiotherapy. Randomisation was by a computer-generated random number code with a block size of four, stratified by treatment centre and disease stage (III or IV). Treatment allocation was not masked. The primary endpoint was failure-free survival calculated from randomisation to locoregional failure, distant failure, or death from any cause; required sample size was 476 patients (238 per group). We did efficacy analyses in our intention-to-treat population. The follow-up is ongoing; in this report, we present the 3-year survival results and acute toxic effects. This trial is registered with ClinicalTrials.gov , number NCT01245959. Findings Between March 1, 2011, and Aug 22, 2013, 241 patients were assigned to induction chemotherapy plus concurrent chemoradiotherapy and 239 to concurrent chemoradiotherapy alone. After a median follow-up of 45 months (IQR 38–49), 3-year failure-free survival was 80% (95% CI 75–85) in the induction chemotherapy plus concurrent chemoradiotherapy group and 72% (66–78) in the concurrent chemoradiotherapy alone group (hazard ratio 0·68, 95% CI 0·48–0·97; p=0·034). The most common grade 3 or 4 adverse events during treatment in the 239 patients in the induction chemotherapy plus concurrent chemoradiotherapy group versus the 238 patients in concurrent chemoradiotherapy alone group were neutropenia (101 42% vs 17 7%), leucopenia (98 41% vs 41 17%), and stomatitis (98 41% vs 84 35%). Interpretation Addition of TPF induction chemotherapy to concurrent chemoradiotherapy significantly improved failure-free survival in locoregionally advanced nasopharyngeal carcinoma with acceptable toxicity. Long-term follow-up is required to determine long-term efficacy and toxicities. Funding Shenzhen Main Luck Pharmaceuticals Inc, Sun Yat-sen University Clinical Research 5010 Program (2007037), National Science and Technology Pillar Program during the Twelfth Five-year Plan Period (2014BAI09B10), Health & Medical Collaborative Innovation Project of Guangzhou City (201400000001), Planned Science and Technology Project of Guangdong Province (2013B020400004), and The National Key Research and Development Program of China (2016YFC0902000).
Recently, compressive sensing (CS) has been successfully used in inverse synthetic aperture radar (ISAR) imaging. Since the exact sparse reconstruction, i.e., l 0 -norm constraint, is NP hard, l 1 ...-norm relaxation is widely used at the cost of performance degradation in the sparseness of the solution. The performance of existing CS-based ISAR imaging algorithms is sensitive to the regularized factor, which should be adjusted manually. This makes the existing algorithms inconvenient to be used in practice. It is well known that sparse Bayesian learning (SBL) acts as an effective tool in regression and classification, which is closely related to the CS. Furthermore, all the necessary parameters can be estimated using an efficient evidence maximization procedure in SBL, which retains a preferable property of the l 0 -norm diversity measure and can give more sparse solution. Motivated by that, a fully automated ISAR imaging algorithm based on SBL is proposed in this paper. Experimental results based on simulated and measured data show that the proposed algorithm keeps a better balance between the computation load and the sparsity of the reconstruction signal than the existing algorithms.
Porous carbon materials demonstrate extensive applications for their attractive characteristics. Mechanical flexibility is an essential property guaranteeing their durability. After decades of ...research efforts, compressive brittleness of porous carbon materials is well resolved. However, reversible stretchability remains challenging to achieve due to the intrinsically weak connections and fragile joints of the porous carbon networks. Herein, it is presented that a porous all‐carbon material achieving both elastic compressibility and stretchability at large strain from −80% to 80% can be obtained when a unique long‐range lamellar multi‐arch microstructure is introduced. Impressively, the porous all‐carbon material can maintain reliable structural robustness and durability under loading condition of cyclic compressing–stretching process, similar to a real metallic spring. The unique performance renders it as a promising platform for making smart vibration and magnetism sensors, even capable of operating at extreme temperatures. Furthermore, this study provides valuable insights for creating highly stretchable and compressible porous materials from other neat inorganic components for diverse applications in future.
A porous spring‐like all‐carbon material achieving both elastic compressibility and stretchability at large strain from −80% to 80% is obtained when a unique long‐range lamellar multi‐arch microstructure is designed. The excellent mechanical performance combined with the intrinsic advantages of carbon makes it a promising platform for making smart vibration and magnetism sensors that can work at extreme temperatures.
Zeolites have been widely used in industry owing to their ordered micropores and stable frameworks. The pore sizes and shapes are the key parameters that affect the selectivity and efficiency in ...their applications in catalysis, sorption, and separation. Zeolites with pores defined by 10 and 12 TO4 tetrahedra are often used for various catalytic processes. To optimize the performance of zeolites, it is extremely desirable to fine‐tune the pore sizes/shapes. The first germanosilicate zeolite with a three‐dimensional 11×11×12‐ring channel system, PKU‐16 (PKU, Peking University) is presented. Nanosized PKU‐16 was structurally characterized by the new three‐dimensional rotation electron diffraction (RED) technique. PKU‐16 is structurally related to the zeolite β polymorph C (BEC, 12×12×12‐ring channels) by rotating half of the four‐rings in double mtw units.
A stable germanosilicate with 3D 11×11×12 ring channels, PKU‐16 (see picture), was synthesized with a simple organic structure‐directing agent. Nanosized PKU‐16 was structurally characterized by the new rotation electron diffraction methods. The structure of PKU‐16 is related with zeolite β polymorph C by rotating half of the 4‐rings in the double mtw units.
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