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Optimization of beamforming and path planning for UAV-assisted wireless relay networks

Chinese Journal of Aeronautics 2014年第2期27卷 313-320页

作者： Ouyang jian Zhuang Yi Lin Min Liu jia College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics PLA University of Science and Technology National Mobile Communications Research Laboratory Southeast University Computer Center Nanjing University of Aeronautics and Astronautics

Recently, unmanned aerial vehicles （UAVs） acting as relay platforms have attracted considerable attention due to the advantages of extending coverage and improving connectivity for long-range communications. Specifically, in the scenario where the access point （AP） is mobile, a UAV needs to find an efficient path to guarantee the connectivity of the relay link. Motivated by this fact, this paper proposes an optimal design for beamforming （BF） and UAV path planning. First of all, we study a dual-hop amplify-and-forward （AF） wireless relay network, in which a UAV is used as relay between a mobile AP and a fixed base station （BS）. In the network, both of the AP and the BS are equipped with multiple antennas, whereas the UAV has a single antenna. Then, we obtain the output signal^to-noise ratio （SNR） of the dual-hop relay network. Based on the criterion of maximizing the output SNR, we develop an optimal design to obtain the solution of the optimal BF weight vector and the UAV heading angle. Next, we derive the closed-form outage probability （OP） expression to investigate the performance of the dual-hop relay network conveniently. Finally, computer simulations show that the proposed approach can obtain nearly optimal flying path and OP performance, indicating the effectiveness of the proposed algorithm. Furthermore, we find that increasing the antenna number at the BS or the maximal heading angle can significantly improve the performance of the considered relay network.

关键词： Aircraft communication Beam forming Path planning Unmanned aerial vehicles Wireless relay networks

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High winding number of topological phase in non-unitary periodic quantum walk

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Chinese Physics B 2021年第10期30卷 120-126页

作者： Yali jia Zhi-jian Li Institute of Theoretical Physics Shanxi UniversityTaiyuan 030006China

Topological phases and their associated multiple edge states are studied by constructing a one-dimensional non-unitary multi-period quantum walk with parity-time *** is shown that large topological numbers can be obtained when choosing an appropriate time *** maximum value of the winding number can reach the number of periods in the one-step evolution *** validity of the bulk-edge correspondence is confirmed,while for an odd-period quantum walk and an even-period quantum walk,they have different configurations of the 0-energy edge state andπ-energy edge *** the boundary,two kinds of edge states always coexist in equal amount for the odd-period quantum walk,however three cases including equal amount,unequal amount or even only one type may occur for the even-period quantum walk.

关键词： periodic quantum walk high winding number edge states

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Context-Based Moving Object Trajectory Uncertainty Reduction and Ranking in Road Network

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Journal of Computer Science & Technology 2016年第1期31卷 167-184页

作者： jian Dai Zhi-Ming Ding jia-Jie Xu School of Computer Science Beijing University of Technology Beijing 100124 China University of Chinese Academy of Sciences Beijing 100049 China Institute of Software Chinese Academy of Sciences Beijing 100190 China School of Computer Science and Technology Soochow University Suzhou 215000 China

To support a large amount of GPS data generated from various moving objects, the back-end servers usually store low-sampling-rate trajectories. Therefore, no precise position information can be obtained directly from the back-end servers and uncertainty is an inherent characteristic of the spatio-temporal data. How to deal with the uncertainty thus becomes a basic and challenging problem. A lot of researches have been rigidly conducted on the uncertainty of a moving object itself and isolated from the context where it is derived. However, we discover that the uncertainty of moving objects can be efficiently reduced and effectively ranked using the context-aware information. In this paper, we focus on context- aware information and propose an integrated framework, Context-Based Uncertainty Reduction and Ranking （CURR）, to reduce and rank the uncertainty of trajectories. Specifically, given two consecutive samplings, we aim to infer and rank the possible trajectories in accordance with the information extracted from context. Since some context-aware information can be used to reduce the uncertainty while some context-aware information can be used to rank the uncertainty, to leverage them accordingly, CURR naturally consists of two stages： reduction stage and ranking stage which complement each other. We also implement a prototype system to validate the effectiveness of our solution. Extensive experiments are conducted and the evaluation results demonstrate the efficiency and high accuracy of CURR.

关键词： moving object trajectory uncertainty reduction road network context-aware information

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Pre-detection and dual-dictionary sparse representation based face recognition algorithm in non-sufficient training samples

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Journal of Systems Engineering and Electronics 2018年第1期29卷 196-202页

作者： ZHAO jian ZHANG Chao ZHANG Shunli LU Tingting SU Weiwen jia jian School of Information Science and Technology Northwest University

Face recognition based on few training samples is a challenging task. In daily applications, sufficient training samples may not be obtained and most of the gained training samples are in various illuminations and poses. Non-sufficient training samples could not effectively express various facial conditions, so the improvement of the face recognition rate under the non-sufficient training samples condition becomes a laborious mission. In our work, the facial pose pre-recognition(FPPR) model and the dualdictionary sparse representation classification(DD-SRC) are proposed for face recognition. The FPPR model is based on the facial geometric characteristic and machine learning, dividing a testing sample into full-face and profile. Different poses in a single dictionary are influenced by each other, which leads to a low face recognition rate. The DD-SRC contains two dictionaries, full-face dictionary and profile dictionary, and is able to reduce the interference. After FPPR, the sample is processed by the DD-SRC to find the most similar one in training samples. The experimental results show the performance of the proposed algorithm on olivetti research laboratory(ORL) and face recognition technology(FERET) databases, and also reflect comparisons with SRC, linear regression classification(LRC), and two-phase test sample sparse representation(TPTSSR).

关键词： face recognition facial pose pre-recognition(FPPR) dual-dictionary sparse representation method machine learning

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Powell dynamic identification of displacement parameters of indeterminate thin-walled curve box based on FCSE theory

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Acta Mechanica Sinica 2011年第3期27卷 452-460页

作者： jian Zhang Chu-Wei Zhou jia-Shou Zhuo College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics 210016 Nanjing China College of Mechanics and Material Hohai University 210098 Nanjing China

The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and *** parameters鈥？iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element（FCSE） partial differentiation,which proves high computation effciency of the studied method.

关键词： Powell theory - Indeterminate curve box . Displacement parameters - Fibonacci search method.Flexibility theory

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Distributed incremental bias-compensated RLS estimation over multi-agent networks

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Science China(Information Sciences) 2017年第3期60卷 153-167页

作者： jian LOU Lijuan jia Ran TAO Yue WANG School of Information and Electronics Beijing Institute of Technology

In this paper, we study the problem of distributed bias-compensated recursive least-squares(BCRLS) estimation over multi-agent networks, where the agents collaborate to estimate a common parameter of interest. We consider the situation where both input and output of each agent are corrupted by unknown additive noise. Under this condition, traditional recursive least-squares(RLS) estimator is biased, and the bias is induced by the input noise variance. When the input noise variance is available, the effect of the noise-induced bias can be removed at the expense of an increase in estimation variance. Fortunately, it has been illustrated that distributed collaboration between agents can effectively reduce the variance and can improve the stability of the estimator. Therefore, a distributed incremental BC-RLS algorithm and its simplified version are proposed in this paper. The proposed algorithms can collaboratively obtain the estimates of the unknown input noise variance and remove the effect of the noise-induced bias. Then consistent estimation of the unknown parameter can be achieved in an incremental fashion. Simulation results show that the incremental BC-RLS solutions outperform existing solutions in some enlightening ways.

关键词： distributed parameter estimation bias compensation incremental schemes recursive least-squares multi-agent networks

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The performance of a combined nitritation–anammox reactor treating anaerobic digestion supernatant under various C/N ratios

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Journal of Environmental Sciences 2015年第4期27卷 207-214页

作者： jian Zhao jiane Zuo jia Lin Peng Li State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University

A combined nitritation–anammox reactor was developed to treat the digestion supernatant under various C/N ratios. Due to the difficulties for heterotroph to utilize the refractory organics, the reactor presented relatively stable performance with increasing supernatant addition. Nevertheless, the adverse effects of supernatant would accumulate during the long-term operation and thus weakened the activity and shock resistance of microbes,which further led to the gradual decrease of reactor performance after 92 days＇ *** this circumstance, supernatant with volatile fatty acids（VFAs） residuals was further introduced into the reactor to investigate the performance of combined nitritation–anammox process with VFA addition. With the appearance of VFAs, the nitrogen removal performance gradually restored and the reactor finally achieved stable and efficient performance with C/N ratio of 0.35. The VFA residuals within 150 mg/L in the supernatant served as the extra electron donors and stimulated the heterotrophic denitrification process, which was vital for the enhancement of reactor. The nitrogen removal rate and total nitrogen removal efficiency reached 0.49 kg N/（m^3·day） and 88.8% after 140 days＇ operation, respectively. The combined nitritation–anammox reactor was proved suitable to treat digestion supernatant.

关键词： Combined nitritation–anammox Anaerobic digestion supernatant C/N ratios Volatile fatty acids

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Formation of multiple trimethylsilyl derivatives in the derivatization of 17α-ethinylestradiol with BSTFA or MSTFA followed by gas chromatography-mass spectrometry determination

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Journal of Environmental Sciences 2007年第7期19卷 879-884页

作者： ZHOU Yi-qi WANG Zi-jian jia Ning Sate Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China. College of Environment and Energy Engineering Beijing University of Technology Beijing 100022 China

N,O-bis（trimethylsily）trifluoroacetamide （BSTFA） and N-methyl-N（trimethylsily） trifluoroacetamide （MSTFA） are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone （El） and 17α-ethinylestradiol （EE2）. In this study, three trimethylsilyl （TMS） steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl El, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz （TMSI） in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.

关键词： estrogens water sample GC/MS determination trimethylsilyl steroid derivatives

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羟基磷灰石改性竹笋壳生物炭的合成及吸附性能研究

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分析测试学报 2025年第1期44卷 126-134页

作者：夏蒸雷兰石铁应鲍云云梁汝萍邱建丁东华理工大学核资源与环境国家重点实验室江西南昌330013 南昌大学化学化工学院江西南昌330031

该研究以竹笋壳为原料合成了具有多孔结构和亲水性磷酸基团的羟基磷灰石改性竹笋壳生物炭(BSHAP),用于高效吸附废水中的铀酰离子(UO_(2)^(2+))。BS-HAP的多孔结构可有效增加与UO_(2)^(2+)的接触面积,促进对UO_(2)^(2+)的吸附;BS-HAP中... 详细信息

该研究以竹笋壳为原料合成了具有多孔结构和亲水性磷酸基团的羟基磷灰石改性竹笋壳生物炭(BSHAP),用于高效吸附废水中的铀酰离子(UO_(2)^(2+))。BS-HAP的多孔结构可有效增加与UO_(2)^(2+)的接触面积,促进对UO_(2)^(2+)的吸附;BS-HAP中的磷酸基团可为化学吸附UO_(2)^(2+)提供结合位点,使得BS-HAP对UO_(2)^(2+)具有优异的吸附性能。同时,Ca^(2+)与UO_(2)^(2+)之间的离子交换作用以及生物炭与UO_(2)^(2+)之间的静电相互作用,协同促进了BSHAP对UO_(2)^(2+)的吸附。在酸性条件下,BS-HAP对UO_(2)^(2+)的吸附容量为815.2 mg·g^(-1)。BS-HAP不仅对UO_(2)^(2+)具有强的吸附能力,还具有良好的选择性和稳定性,即使经多次循环使用,仍能保持对UO_(2)^(2+)的高效去除能力。BS-HAP为含铀废水处理提供了有效方法,对推动绿色可持续的废水处理技术发展具有重要意义。

关键词：竹笋壳生物炭羟基磷灰石铀酰离子吸附

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Association of stent thrombectomy and conventional treatment with neuroprotection, complications, anxiety, and depression in acute ischemic stroke patients

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World Journal of Psychiatry 2025年第1期15卷 72-82页

作者： Kai-Jie Yang jia-jian Huang Cai-Xia Xuan Department of Neurology Qinzhou Second People's HospitalQinzhou 535000Guangxi Zhuang Autonomous RegionChina

BACKGROUND Acute ischemic stroke(AIS)is an abrupt blood flow cessation to a specific brain region within a vascular zone,causing a subsequent decline in neurological *** thrombectomy is a recently established technique for treating *** provides the benefits of being a relatively simple and safe procedure,capable of partially enhancing a patient’s ***,some patients may experience endothelial damage and recurrent thrombosis,with clinical outcomes that are not always ***,the efficacy of this method remains *** To survey the association of stent thrombectomy vs standard treatment with neurological function protection,complications,and short-term prognosis in patients diagnosed with *** This study assigned 90 patients with AIS to the observation and control groups(n=45 patients)from December 2020 to December *** thrombectomy was conducted in the observation group,whereas routine treatment was provided to the control *** study assessed the therapeutic outcomes of two groups,including a comparison of their neurological function,living ability,anxiety and depression status,plaque area,serum inflammatory factors,serum Smur100βprotein,neuron-specific enolase(NSE),homocysteine(Hcy),and vascular endo-thelial ***,the incidence of complications was calculated and analyzed for each *** The total effective rate of treatment was 77.78%and 95.56%in the control and observation groups,*** 8 weeks of treatment,the scores on the National Institutes of Health Stroke Scale,Hamilton Anxiety Scale,and Hamilton Depression Scale decreased remarkably;the Barthel index increased remarkably,with better improvement effects of the scores in the observation group(P<0.05);total cholesterol,triglyceride,C-reactive protein,and plaque area lessened remarkably,with fewer patients in the observation group(P<0.05);S-100βprotein,NSE,and Hcy levels lessened remarkably,with fewer patients in

关键词： Stent thrombectomy Acute ischemic stroke Neurological function Complications Short-term prognosis

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