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Genuine (k,m)-Threshold Controlled Teleportation and Multipartite Entanglement 被引量:2
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作者 汪新文 李大创 +1 位作者 杨国健 张登玉 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第6期977-983,共7页
We propose genuine (k, m)-threshold controlling schemes for controlled teleportation via multi-particle entangled states, where the teleportation of a quantum state from a sender (Alice) to a receiver (Bob) is u... We propose genuine (k, m)-threshold controlling schemes for controlled teleportation via multi-particle entangled states, where the teleportation of a quantum state from a sender (Alice) to a receiver (Bob) is under the control of m supervisors such that k (k≤ m) or more of these supervisors can help Bob recover the transferred state. By construction, anyone of our quantum channels is a genuine multipartite entangled state of which any two parts are inseparable. Their properties are compared and contrasted with those of the well-known GHZ, W, and linear cluster states, and also several other genuine multipartite entangled states recently introduced in the literature. 展开更多
关键词 threshold controlled teleportation multipartite entanglement
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Threshold Multiparty Controlled Teleportation of Arbitrary m-Qubit Quantum Information 被引量:1
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作者 YANG Yu-Guang WEN Qiao-Yan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第10期593-596,共4页
We present a (t, .n) threshold multiparty controlled quantum teleportation protocol of an arbitrary m-qubit quantum state between two remote parties. The unknown m-qubit quantum state can be recovered by the receive... We present a (t, .n) threshold multiparty controlled quantum teleportation protocol of an arbitrary m-qubit quantum state between two remote parties. The unknown m-qubit quantum state can be recovered by the receiver under control of a subset of the n controllers if the number of the subset is larger than or equal to a threshold, say, t, but not for any t - 1 or fewer controllers. Our scheme seems to be more practical and more flexible than other existing protocols. The quantum resource required is just m Einstein-Podolsky-Rosen (EPR) pairs plus some single photons. The techniques required are only Bell state measurement, single-qubit unitary operation and yon Neumann measurement. So our scheme is also feasible with present-day technique. 展开更多
关键词 controlled teleportation threshold controlled teleportation ENTANGLEMENT
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Threshold Controlled Scheme of Difference Expansion Techniques for Reversible Watermarking
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作者 蒋历军 郭小涛 +2 位作者 杨浩 赵俊 庄天戈 《Journal of Shanghai Jiaotong university(Science)》 EI 2010年第5期541-548,共8页
Since Tian Jun proposed the difference expansion embedding technique,based on which,many reversible watermarking techniques were proposed.However,these methods do not perform well when the payload is high.In this pape... Since Tian Jun proposed the difference expansion embedding technique,based on which,many reversible watermarking techniques were proposed.However,these methods do not perform well when the payload is high.In this paper,we proposed an expandable difference threshold controlled scheme for these three methods.Experiments show that our scheme improves the performance of these three methods for heavy payload. 展开更多
关键词 difference expansion embedding technique reversible watermarking visual quality difference threshold controlled scheme
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Optimal Threshold Policies for Robust Data Center Control 被引量:1
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作者 WENG Paul 邱泽麒 +2 位作者 COSTANZO John 阴小骐 SINOPOLI Bruno 《Journal of Shanghai Jiaotong university(Science)》 EI 2018年第1期52-60,共9页
With the simultaneous rise of energy costs and demand for cloud computing, efficient control of data centers becomes crucial. In the data center control problem, one needs to plan at every time step how many servers t... With the simultaneous rise of energy costs and demand for cloud computing, efficient control of data centers becomes crucial. In the data center control problem, one needs to plan at every time step how many servers to switch on or off in order to meet stochastic job arrivals while trying to minimize electricity consumption. This problem becomes particularly challenging when servers can be of various types and jobs from different classes can only be served by certain types of server, as it is often the case in real data centers. We model this problem as a robust Markov decision process(i.e., the transition function is not assumed to be known precisely). We give sufficient conditions(which seem to be reasonable and satisfied in practice) guaranteeing that an optimal threshold policy exists. This property can then be exploited in the design of an efficient solving method, which we provide.Finally, we present some experimental results demonstrating the practicability of our approach and compare with a previous related approach based on model predictive control. 展开更多
关键词 data center control Markov decision process threshold policy ROBUSTNESS
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A Computer System for Forecasting the Threshold Period for Crop Weed Control
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作者 LI Jing-tao ZOU Ping +4 位作者 GU Lin FU Yang CUI Hua-wei ZHANG Xing-tao CAI Chang-shu 《Agricultural Sciences in China》 CAS CSCD 2008年第11期1394-1402,共9页
In this article, a model of a weed control threshold forecast system has been established, with related model solving, data checking, database setting up, and system engineering illustration. Moreover, it is tested by... In this article, a model of a weed control threshold forecast system has been established, with related model solving, data checking, database setting up, and system engineering illustration. Moreover, it is tested by a software with data from a sugar cane planting experimental field in Yunnan, China. The methodology behind the detailed system analysis, design, and engineering has been discussed. The issue of how to create a dynamic data-dependent forecast model of a threshold forecast system, whose threshold changes according to the change of planting environment has been solved. Hence an effective solution has been initiated for further development on an agricultural expert system. 展开更多
关键词 weed control threshold forecast system
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Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy
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作者 Philip Kioko Ndonye Samuel Nii Adu Tagoe 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2022年第1期22-35,共14页
Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) ... Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT. 展开更多
关键词 Quality Assurance Statistical Process control Action thresholds Dose Verification External Beam Radiation Therapy
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基于自适应阈值伪谱法的空间机器人轨迹优化
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作者 倪浩 刘壮 +4 位作者 马晓龙 张欧阳 陈萌 刘健行 吴立刚 《哈尔滨工业大学学报》 北大核心 2026年第1期1-11,共11页
为解决传统Radau伪谱法在轨迹优化求解效率与轨迹解可行性之间存在的矛盾,本文提出一种基于自适应阈值的分段升阶伪谱法,用于提升非线性优化问题的求解精度,加快收敛速度。该方法通过动态比较迭代过程中的误差矩阵极大值与标准时间步长... 为解决传统Radau伪谱法在轨迹优化求解效率与轨迹解可行性之间存在的矛盾,本文提出一种基于自适应阈值的分段升阶伪谱法,用于提升非线性优化问题的求解精度,加快收敛速度。该方法通过动态比较迭代过程中的误差矩阵极大值与标准时间步长,在误差超过自适应阈值的区间设置新分段点,并在误差小于偏差阈值的分段内增加配点数,这种策略对轨迹解的平滑/非平滑区间进行针对性优化,从而以较少的分段数和配点数达成轨迹规划目标。相比于传统Radau伪谱法,自适应分段升阶方法能够以较少迭代轮次收敛到期望结果,实现数值精度与求解效率的有效平衡。为验证算法性能,本研究基于自由飞行空间机器人非合作目标捕获场景进行了对比仿真实验。实验结果表明,本文提出的自适应分段升阶方法,在求解耗时和轨迹解的末端精度方面均优于对比方法,显示出更好的综合表现。 展开更多
关键词 自由飞行空间机器人 轨迹规划 最优控制 伪谱法 自适应阈值
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The New Method to Determine Ownership Stake to Exercise Control: An Empirical Analysis on Italian Companies
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作者 Carmelo Intrisano Anna Paola Micheli 《Chinese Business Review》 2013年第11期725-735,共11页
The idea of this work arises from the analysis of the researches developed in the literature on topic of ownership and control that are mostly based on threshold of ownership stake to determine control equal for all c... The idea of this work arises from the analysis of the researches developed in the literature on topic of ownership and control that are mostly based on threshold of ownership stake to determine control equal for all companies and, in most cases, not supported by theoretical arguments and empirical evidences. In fact, the aim of this paper is to build a new method of determining the threshold of ownership stake that allows the shareholder to exercise control. In particular, this survey uses all Italian listed companies as reference, and the minutes of the Ordinary and Extraordinary General Meetings of shareholders, in 2009-2012, as database. The topic can be enriched with further and future researches aiming to adapt this new method in a cross-country investigation and so to identify the different threshold for the countries, on the basis of the different national laws regarding the ownership stakes that affect the control. 展开更多
关键词 ordinary and extraordinary general meetings of shareholders control threshold QUORUM control annual financial statement approval renewal of boards
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Analysis on the Risk Factors of Diabetic Nephropathy and the Critical Value of Blood Pressure Control
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作者 JIA Qi 《外文科技期刊数据库(文摘版)医药卫生》 2021年第3期600-604,共5页
Objective: to explore the risk factors of diabetic nephropathy caused by diabetic patients and the critical value of blood pressure that patients need to control. Methods: 74 patients with diabetic nephropathy who rec... Objective: to explore the risk factors of diabetic nephropathy caused by diabetic patients and the critical value of blood pressure that patients need to control. Methods: 74 patients with diabetic nephropathy who received treatment in our hospital from March 2019 to March 2020 were selected. After the patients were admitted to our hospital, the medical staff first thoroughly understood the patient's physical condition. The 74 patients were divided into group F as a reference and group Y for observation according to the patient's condition. The patients in group F were determined to have the disease as non-diabetic nephropathy according to the clinical detection standard. Group Y patients were identified as diabetic nephropathy patients according to the clinical diagnostic criteria. The clinical data of the patients were analyzed in detail. The patient's age, onset course and related indicators were recorded and compared. The risk factors of diabetic nephropathy were determined based on regression analysis. The protective factor is high density lipoprotein, and other factors are irrelevant. The critical blood pressure values of the patients were 137.6mmhg and 78.01mmhg respectively. Conclusion: the analysis of the risk factors of diabetic nephropathy. The risk factors of diabetic nephropathy should be controlled scientifically and the critical value of blood pressure should be strictly controlled to delay the development of the patient's condition. 展开更多
关键词 diabetic nephropathy risk factors blood pressure control threshold ANALYSIS
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Spacecraft formation control strategy on Sun-Earth Lissajous orbit 被引量:1
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作者 李鹏 崔平远 崔祜涛 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第6期805-809,共5页
To carry out the deep space exploration tasks near Sun-Earth Libration point L2, the CRTBP dynamic model was built up and the numerical conditional quasi-periodic orbit (Lissajons orbit) was computed near L2. Then, ... To carry out the deep space exploration tasks near Sun-Earth Libration point L2, the CRTBP dynamic model was built up and the numerical conditional quasi-periodic orbit (Lissajons orbit) was computed near L2. Then, a formation controller was designed with linear matrix inequality to overcome the difficuhy of parameter tuning. To meet the demands of formation accuracy and present thruster's capability, a threshold scheme was adopted for formation control. Finally, some numerical simulations and analysis were completed to demonstrate the feasibility of the proposed control strategy. 展开更多
关键词 deep space formation eollinear libration point Lissajous orbit linear matrix inequality threshold control
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A (2, 3) quantum threshold scheme based on Greenberger-Horne-Zeilinger state 被引量:2
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作者 李渊 曾贵华 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第10期2875-2879,共5页
In this paper, by using properties of quantum controlled-not manipulation and entanglement states, we have designed a novel (2, 3) quantum threshold scheme based on the Greenberger- Horne -Zeilinger (GHZ) state. T... In this paper, by using properties of quantum controlled-not manipulation and entanglement states, we have designed a novel (2, 3) quantum threshold scheme based on the Greenberger- Horne -Zeilinger (GHZ) state. The proposed scheme involves two phases, i.e. a secret sharing phase and a secret phase. Detailed proofs show that the proposed scheme is of unconditional security. Since the secret is shared among three participants, the proposed scheme may be applied to quantum key distribution and secret sharing. 展开更多
关键词 quantum threshold controlled-not manipulation secret sharing GHZ state
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Quantitative Analysis Model and Application of the Hydrocarbon Distribution Threshold 被引量:6
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作者 JIANG Fujie PANG Xiongqi GUO Jigang 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第1期232-242,共11页
Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of "source control theory", the concept of a hydrocarbon distribution threshold wa... Hydrocarbon source rock obviously controls the formation and distribution of hydrocarbon reservoirs. Based on the geological concept of "source control theory", the concept of a hydrocarbon distribution threshold was put forward. This means the maximum range for hydrocarbon controlled by the source rock conditions to migrate in the hydrocarbon basins. Three quantitative analysis models are proposed on this basis, namely the hydrocarbon accumulation probability, maximum hydrocarbon scale threshold and reserve distribution probability, which respectively refer to the probability of forming a hydrocarbon reservoir, the possible maximum scale of the hydrocarbon reservoir and the percentage of reserve distribution in a certain area within the hydrocarbon distribution threshold. Statistical analysis on 539 hydrocarbon reservoirs discovered in 28 hydrocarbon source kitchens from seven sedimentary basins and sags of eastern China shows the maximum reservoir scale possibly formed in the hydrocarbon basin, hydrocarbon accumulation probability and oil and gas reserve distribution probability are all controlled by the characteristics of the hydrocarbon source rock. Generally, as the distances from the hydrocarbon source rock center and hydrocarbon discharge boundary get longer and the hydrocarbon discharge intensity of hydrocarbon source rock center gets smaller, there will be lower probability of hydrocarbon accumulation. Corresponding quantitative models are established based on single factor statistics and multivariate analysis. Practical application in the Jiyang Depression shows that the prediction from the quantitative analysis model for the hydrocarbon distribution threshold agree well with the actual exploration results, indicating that the quantitative analysis model is likely to be a feasible tool. 展开更多
关键词 source control theory scale threshold distribution threshold Jiyang Depression hydrocarbon discharge threshold PROBABILITY
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Double-Moduli Gaussian Encryption/Decryption with Primary Residues and Secret Controls 被引量:1
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作者 Boris S. Verkhovsky 《International Journal of Communications, Network and System Sciences》 2011年第7期475-481,共7页
In this paper an encryption-decryption algorithm based on two moduli is described: one in the real field of integers and another in the field of complex integers. Also the proper selection of cryptographic system para... In this paper an encryption-decryption algorithm based on two moduli is described: one in the real field of integers and another in the field of complex integers. Also the proper selection of cryptographic system parameters is described. Several numeric illustrations explain step-by-step how to precondition a plaintext, how to select secret control parameters, how to ensure feasibility of all private keys and how to avoid ambiguity in the process of information recovery. The proposed cryptographic system is faster than most of known public key cryptosystems, since it requires a small number of multiplications and additions, and does not require exponentiations for its implementation. 展开更多
关键词 ambiguity-free INFORMATION recovery complex modulus CRYPTOSYSTEM design cycling identity INFORMATION hiding PLAINTEXT preconditioning PRIMARY residue public-key cryptography secret controls threshold parameters
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大豆蚜的发生与防控
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作者 樊东 董爽 +3 位作者 姚磊 杨洪佳 戴长春 唐宇 《吉林农业大学学报》 北大核心 2025年第5期772-779,共8页
大豆蚜是大豆田中常见的害虫之一,在世界上的分布十分广泛。我国是大豆蚜的原发地之一,在东北、华北、西南、华南等地区均普遍发生。大豆蚜的成蚜和若蚜集中在大豆植株的顶尖嫩叶、嫩芽和嫩荚上进行刺吸为害,造成植株营养不良、生长发... 大豆蚜是大豆田中常见的害虫之一,在世界上的分布十分广泛。我国是大豆蚜的原发地之一,在东北、华北、西南、华南等地区均普遍发生。大豆蚜的成蚜和若蚜集中在大豆植株的顶尖嫩叶、嫩芽和嫩荚上进行刺吸为害,造成植株营养不良、生长发育受阻,同时大豆蚜也是多种植物病毒病的传播者,通过传播疾病造成大豆产量的叠加损失。近年来,随着大豆种植面积的增加和新农业技术的出现,大豆蚜的发生和防治也出现了新的特点。对大豆蚜的分布、为害情况、引起种群动态的因素、预测预报、防治指标、综合治理以及未来展望进行了概述,以期为大豆蚜的生物学研究和生产中的防控提供指导和思路。 展开更多
关键词 大豆蚜 种群动态 预测预报 防治指标 综合治理
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A new dynamic pushback control method for reducing fuel-burn costs: Using predicted taxi-out time 被引量:13
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作者 Guan LIAN Yaping ZHANG +2 位作者 Zhiwei XING Qian LUO Shaowu CHENG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第3期660-673,共14页
Long departure-taxi-out time leads to significant airport surface congestion, fuel-burn costs, and excessive emissions of greenhouse gases. To reduce these undesirable effects, a Predicted taxi-out time-based Dynamic ... Long departure-taxi-out time leads to significant airport surface congestion, fuel-burn costs, and excessive emissions of greenhouse gases. To reduce these undesirable effects, a Predicted taxi-out time-based Dynamic Pushback Control(PDPC) method is proposed. The implementation of this method requires two steps: first, the taxi-out times for aircraft are predicted by the leastsquares support-vector regression approach of which the parameters are optimized by an introduced improved Firefly algorithm. Then, a dynamic pushback control model equipped with a linear gate-hold penalty function is built, along with a proposed iterative taxiway queue-threshold optimization algorithm for solving the model. A case study with data obtained from Beijing International airport(PEK) is presented. The taxi-out time prediction model achieves predictive accuracy within 3 min and 5 min by 84.71% and 95.66%, respectively. The results of the proposed pushback method show that total operation cost and fuel-burn cost achieve a 14.0% and 21.1%reduction, respectively, as compared to the traditional K-control policy.(3) From the perspective of implementation, using PDPC policy can significantly reduce the queue length in taxiway and taxi-out time. The total operation cost and fuel-burn cost can be curtailed by 37.2% and 52.1%,respectively, as compared to the non-enforcement of any pushback control mechanism. These results show that the proposed pushback control model can reduce fuel-burn costs and airport surface congestion effectively. 展开更多
关键词 Airport surface operation Fuel-burn cost Gate-hold TIME Pushback control Taxi-out TIME prediction Taxiway queue threshold
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地震作用下重载铁路桥上列车脱轨规律及预警阈值研究
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作者 龚凯 罗江铃 +2 位作者 向俊 杨泽宇 刘向明 《中南大学学报(自然科学版)》 北大核心 2025年第9期4012-4023,共12页
为预防地震引起的重载铁路桥上列车脱轨事故,基于货物列车-轨道-桥梁系统空间振动计算模型,将地震波作为外部激励,建立地震作用下车-轨-桥系统空间振动计算模型;根据列车脱轨能量随机分析方法,提出地震作用下重载铁路桥上列车脱轨全过... 为预防地震引起的重载铁路桥上列车脱轨事故,基于货物列车-轨道-桥梁系统空间振动计算模型,将地震波作为外部激励,建立地震作用下车-轨-桥系统空间振动计算模型;根据列车脱轨能量随机分析方法,提出地震作用下重载铁路桥上列车脱轨全过程计算方法及列车脱轨预警原理,计算地震强度及车速条件下桥上列车脱轨全过程变化,分析地震强度及车速对轮轨相互作用的影响。研究结果表明:当地震峰值加速度大于或等于1.5 m/s^(2)时,车轮容易发生脱轨;脱轨系数及轮重减载率随地震峰值加速度增大而增大,其中,部分脱轨系数超过限值且车轮完全减载;地震作用对梁跨跨中及墩顶横向位移影响显著;将车轮脱轨瞬间转向架与钢轨横向相对位移作为控制指标,考虑安全系数,得到了具有预防列车脱轨功能的控制阈值。 展开更多
关键词 铁道工程 重载铁路 货物列车 地震作用 脱轨规律 控制阈值
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Autonomous Lane Keeping Solution Based on Adaptive Gray Threshold and Region of Interest
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作者 陈泽友 李文生 《自动化博览》 2011年第S2期127-131,共5页
Autonomous lane keeping is an important technology in intelligent transportation,which is used to avoid unnecessary traffic accidents caused by lane departure.To adapt different lighting environment,and make up ordina... Autonomous lane keeping is an important technology in intelligent transportation,which is used to avoid unnecessary traffic accidents caused by lane departure.To adapt different lighting environment,and make up ordinary Hough transform’s shortcomings of tardiness and poor immunity,we propose an improved algorithm by using adaptive gray threshold and setting Region of interest(ROI),to do the quick Hough transform for tracking lane line,implementing autonomous lane keeping. The dynamic adaptive threshold method can be suitable with different lighting conditions and quickly,accurately remove most of the information not relative to lane line.Meanwhile setting ROI can let the program only care about the specific region which can provide useful information and further reduce the processing data.And then on the basic of identification,we put forward some efficient innovation strategy about the control logic of straight state,curve state and the transition state.The experiment proves that this solution greatly raises efficiency. 展开更多
关键词 ADAPTIVE GRAY threshold Region of Interest(ROI) control logic MONOCULAR vision
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电针治疗突发性耳聋疗效Meta分析 被引量:1
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作者 刘文静 姜瑾雯 +1 位作者 王海韵 王顺兰 《新中医》 2025年第1期104-109,共6页
目的:通过循证医学方法系统评价电针治疗突发性耳聋的临床疗效。方法:系统检索中国知网、万方、维普、Pubmed、Embase、Web of Science、Cochrane Library数据库中自建库至2024年10月7日以来电针治疗突发性耳聋的随机对照试验,由2名研... 目的:通过循证医学方法系统评价电针治疗突发性耳聋的临床疗效。方法:系统检索中国知网、万方、维普、Pubmed、Embase、Web of Science、Cochrane Library数据库中自建库至2024年10月7日以来电针治疗突发性耳聋的随机对照试验,由2名研究者参考Cochrane协作网提供的偏倚风险评估工具,采用RevMan 5.3软件进行Meta分析。结果:共纳入8篇文献,样本量为638例,试验组321例,对照组317例。Meta分析结果显示,试验组电针治疗突发性耳聋的总有效率(RR=1.23,95%CI[1.07,1.41],P=0.003)、治愈率(RR=1.73,95%CI[1.28,2.34],P=0.0004)、眩晕总有效率(RR=1.25,95%CI[0.99,1.57],P=0.06)均高于对照组;试验组平均听阈值低于对照组(MD=-6.29,95%CI[-9.01,-3.56],P<0.00001),差异均有统计学意义(P<0.05)。结论:电针治疗突发性耳聋可以提高突发性耳聋总有效率、治愈率、眩晕总有效率,改善平均听阈值。 展开更多
关键词 突发性耳聋 电针 随机对照试验 听阈值 Meta分析
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水污染治理与农业生态效率关系研究:基于经济门槛视角 被引量:2
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作者 张玲玲 黎娜 《水利水电技术(中英文)》 北大核心 2025年第2期168-178,共11页
【目的】农业面源污染尤其是种植业面源污染,成为水环境首要致污因素,推动农业绿色发展势必要重视水污染治理成效。研究经济门槛下水污染治理与农业生态效率的关系,有助于探索农业绿色发展的更优策略。【方法】首先构建三阶段非期望产出... 【目的】农业面源污染尤其是种植业面源污染,成为水环境首要致污因素,推动农业绿色发展势必要重视水污染治理成效。研究经济门槛下水污染治理与农业生态效率的关系,有助于探索农业绿色发展的更优策略。【方法】首先构建三阶段非期望产出SBM模型,核算剔除外部环境与随机误差干扰的农业生态效率,然后采用面板门槛效应模型估计水污染治理与农业生态效率的差异性关联关系,并计算出具体的经济门槛值。【结果】结果显示:不同的农村经济水平下,水污染治理与农业生态效率呈非线性关系,存在双重门槛效应,对应门槛值分别为8796元和12897元。【结论】结果表明:农村经济水平等外部环境因素干扰农业生态效率核算结果;农村经济富裕程度越高,水污染治理与农业生态效率关系越协调。因此,各省(自治区、直辖市)应根据农村经济所处具体阶段,灵活调整农业绿色发展策略优先级,确保水污染治理措施的有效性和针对性。 展开更多
关键词 水环境 水污染治理 农业生态效率 门槛效应模型 农村经济水平 三阶段SBM模型
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Server-aided access control for cloud computing 被引量:1
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作者 WENG Jian WENG Jia-si +1 位作者 LIU Jia-nan HOU Lin 《网络与信息安全学报》 2016年第10期58-76,共19页
With the massive diffusion of cloud computing, more and more sensitive data is being centralized into the cloud for sharing, which brings forth new challenges for the security and privacy of outsourced data. To addres... With the massive diffusion of cloud computing, more and more sensitive data is being centralized into the cloud for sharing, which brings forth new challenges for the security and privacy of outsourced data. To address these challenges, the server-aided access control(SAAC) system was proposed. The SAAC system builds upon a variant of conditional proxy re-encryption(CPRE) named threshold conditional proxy re-encryption(TCPRE). In TCPRE, t out of n proxies can re-encrypt ciphertexts(satisfying some specified conditions) for the delegator(while up to t-1 proxies cannot), and the correctness of the re-encrypted ciphertexts can be publicly verified. Both features guarantee the trust and reliability on the proxies deployed in the SAAC system. The security models for TCPRE were formalized, several TCPRE constructions were proposed and that our final scheme was secure against chosen-ciphertext attacks was proved. 展开更多
关键词 计算机网络 网络管理 应用程序 信息安全
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