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Intrusion Detection Algorithm Based on Model Checking Interval Temporal Logic 被引量:5
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作者 朱维军 王忠勇 张海宾 《China Communications》 SCIE CSCD 2011年第3期66-72,共7页
Model checking based on linear temporal logic reduces the false negative rate of misuse detection.However,linear temporal logic formulae cannot be used to describe concurrent attacks and piecewise attacks.So there is ... Model checking based on linear temporal logic reduces the false negative rate of misuse detection.However,linear temporal logic formulae cannot be used to describe concurrent attacks and piecewise attacks.So there is still a high rate of false negatives in detecting these complex attack patterns.To solve this problem,we use interval temporal logic formulae to describe concurrent attacks and piecewise attacks.On this basis,we formalize a novel algorithm for intrusion detection based on model checking interval temporal logic.Compared with the method based on model checking linear temporal logic,the new algorithm can find unknown succinct attacks.The simulation results show that the new method can effectively reduce the false negative rate of concurrent attacks and piecewise attacks. 展开更多
关键词 network security intrusion detection misuse detection interval temporal logic model checking
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Statistical damage detection method for frame structures using a confidence interval 被引量:2
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作者 Li Weiming Zhu Hongping +1 位作者 Luo Hanbin Xia Yong 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第1期133-140,共8页
A novel damage detection method is applied to a 3-story frame structure,to obtain statistical quantification control criterion of the existence,location and identification of damage.The mean,standard deviation,and exp... A novel damage detection method is applied to a 3-story frame structure,to obtain statistical quantification control criterion of the existence,location and identification of damage.The mean,standard deviation,and exponentially weighted moving average(EWMA)are applied to detect damage information according to statistical process control(SPC)theory.It is concluded that the detection is insignificant with the mean and EWMA because the structural response is not independent and is not a normal distribution.On the other hand,the damage information is detected well with the standard deviation because the influence of the data distribution is not pronounced with this parameter.A suitable moderate confidence level is explored for more significant damage location and quantification detection,and the impact of noise is investigated to illustrate the robustness of the method. 展开更多
关键词 damage detection standard deviation statistical method confidence interval noise
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Weak Fault Detection of Rotor Winding Inter-Turn Short Circuit in Excitation System Based on Residual Interval Observer
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作者 Gang Liu Xinqi Chen +4 位作者 Lijuan Bao Linbo Xu Chaochao Dai Lei Yang Chengmin Wang 《Structural Durability & Health Monitoring》 EI 2023年第4期337-351,共15页
Aiming at the fact that the rotor winding inter-turn weak faults can hardly be detected due to the strong electromagnetic coupling effect in the excitation system,an interval observer based on current residual is desi... Aiming at the fact that the rotor winding inter-turn weak faults can hardly be detected due to the strong electromagnetic coupling effect in the excitation system,an interval observer based on current residual is designed.Firstly,the mechanism of the inter-turn short circuit of the rotor winding in the excitation system is modeled under the premise of stable working conditions,and electromagnetic decoupling and system simplification are carried out through Park Transform.An interval observer is designed based on the current residual in the two-phase coordinate system,and the sensitive and stable conditions of the observer is preset.The fault diagnosis process based on the interval observer is formulated,and the observer gain matrix is convexly optimized by linear matrix inequality.The numerical simulation and experimental results show that the inter-turn short circuit weak fault is hardly detected directly through the current signal,but the fault is quickly and accurately diagnosed through the residual internal observer.Compared with the traditional fault diagnosis method based on excitation current,the diagnosis speed and accuracy are greatly improved,and the probability of misdiagnosis also decreases.This method provides a theoretical basis for weak fault identification of excitation systems,and is of great significance for the operation and maintenance of excitation systems. 展开更多
关键词 Excitation system interval observer rotor winding weak fault detection inter-turn shortcut
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Implementation of a Multi-sampling-frequency System for RR-interval Timing and Blood Pressure Detection
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作者 XU Liang FAN Bao-lin +1 位作者 WANG Xing PENG Yi 《Chinese Journal of Biomedical Engineering(English Edition)》 2006年第4期151-158,共8页
In order to analyze the experimental cardiovascular signal with high accuracy, a system, integrating real-time monitoring and off-line further analysis, was developed and verified. The design, data processing and anal... In order to analyze the experimental cardiovascular signal with high accuracy, a system, integrating real-time monitoring and off-line further analysis, was developed and verified. The design, data processing and analysis methods as well as testing results are described. With 5 sampling frequency choices and 8 channel data acquisition, the system achieved high performances in beat-to-beat monitoring, signal processing and analysis. Tests were carried out to validate its performance in real-time monitoring, effectiveness of digital filters, QRS and blood pressure detection reliability, and RR-interval timing accuracy. The QRS detection rate was at least 99.46% for the records with few noises from MIT-BIH arrhythmia database using the algorithm for real-time monitoring, and no less than 96.43% for the records with some noises. In the condition that noise amplitude levels were less than 80%,the standard deviations for RR-interval timing were less than 1 ms with a generated ECG corrupted with various noises from MIT-BIH Noise Stress Test Database. Besides, the system is open for function expansion to meet further study-specific needs. 展开更多
关键词 Experimental cardiovascular data Beat-to-beat detection ECG signal processing RR-interval timing accuracy Blood pressure detection
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A Transformer-based approach for anomaly detection in intelligent well completions
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作者 ARANHA Esteves Pedro POLICARPO Angelica Nara SAMPAIO Augusto Marcio 《Petroleum Exploration and Development》 2025年第4期1029-1040,共12页
This study introduces a novel methodology and makes case studies for anomaly detection in multivariate oil production time-series data,utilizing a supervised Transformer algorithm to identify spurious events related t... This study introduces a novel methodology and makes case studies for anomaly detection in multivariate oil production time-series data,utilizing a supervised Transformer algorithm to identify spurious events related to interval control valves(ICVs)in intelligent well completions(IWC).Transformer algorithms present significant advantages in time-series anomaly detection,primarily due to their ability to handle data drift and capture complex patterns effectively.Their self-attention mechanism allows these models to adapt to shifts in data distribution over time,ensuring resilience against changes that can occur in time-series data.Additionally,Transformers excel at identifying intricate temporal dependencies and long-range interactions,which are often challenging for traditional models.Field tests conducted in the ultradeep water subsea wells of the Santos Basin further validate the model’s capability for early anomaly identification of ICVs,minimizing non-productive time and safeguarding well integrity.The model achieved an accuracy of 0.9544,a balanced accuracy of 0.9694 and an F1-Score of 0.9574,representing significant improvements over previous literature models. 展开更多
关键词 anomaly detection intelligent well completion interval control valve well integrity oil well monitoring deep learning Transformer algorithm
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Confidence Interval Estimation of the Correlation in the Presence of Non-Detects
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作者 Courtney E. McCracken Stephen W. Looney 《Open Journal of Statistics》 2021年第3期463-475,共13页
This article deals with correlating two variables that have values that fall below the known limit of detection (LOD) of the measuring device;these values are known as non-detects (NDs). We use simulation to compare s... This article deals with correlating two variables that have values that fall below the known limit of detection (LOD) of the measuring device;these values are known as non-detects (NDs). We use simulation to compare several methods for estimating the association between two such variables. The most commonly used method, simple substitution, consists of replacing each ND with some representative value such as LOD/2. Spearman’s correlation, in which all NDs are assumed to be tied at some value just smaller than the LOD, is also used. We evaluate each method under several scenarios, including small to moderate sample size, moderate to large censoring proportions, extr</span><span style="font-family:Verdana;">eme imbalance in censoring proportions, and non-bivariate nor</span><span style="font-family:Verdana;">mal (BVN) data. In this article, we focus on the coverage probability of 95% confidence intervals obtained using each method. Confidence intervals using a maximum likelihood approach based on the assumption of BVN data have acceptable performance under most scenarios, even with non-BVN data. Intervals based on Spearman’s coefficient also perform well under many conditions. The methods are illustrated using real data taken from the biomarker literature. 展开更多
关键词 Confidence interval Coverage Probability Left Censoring Limit of detection Maximum Likelihood Spearman Correlation
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Sessile serrated adenoma detection rate is correlated with adenoma detection rate 被引量:2
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作者 Daisuke Ohki Yosuke Tsuji +15 位作者 Tomohiro Shinozaki Yoshiki Sakaguchi Chihiro Minatsuki Hiroto Kinoshita Keiko Niimi Satoshi Ono Yoku Hayakawa Shuntaro Yoshida Atsuo Yamada Shinya Kodashima Nobutake Yamamichi Yoshihiro Hirata Tetsuo Ushiku Mitsuhiro Fujishiro Masashi Fukayama Kazuhiko Koike 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2018年第3期82-90,共9页
AIM To investigated the association between adenoma detection rate(ADR) and sessile serrated ADR(SSADR) and significant predictors for sessile serrated adenomas(SSA) detection.METHODS This study is a retrospective, si... AIM To investigated the association between adenoma detection rate(ADR) and sessile serrated ADR(SSADR) and significant predictors for sessile serrated adenomas(SSA) detection.METHODS This study is a retrospective, single-center analysis. Total colonoscopies performed by the gastroenterologists at the University of Tokyo Hospital between January and December 2014 were retrospectively identified. Polyps were classified as low-grade or high-grade adenoma, cancer, SSA, or SSA with cytological dysplasia, and the prevalence of each type of polyp was investigated. Predictors of adenoma and SSA detection were examined using logistic generalized estimating equation models. The association between ADR and SSADR for each gastroenterologist was investigated by calculating a correlation coefficient weighted by the number of each gastroenterologist's examination.RESULTS A total of 3691 colonoscopies performed by 35 gastroenterologists were assessed. Overall, 978 (26.5%) low-and 84 (2.2%) high-grade adenomas, 81 (2.2%) cancers, 66 (1.8%) SSAs, and 2 (0.1%) SSAs with cytological dysplasia were detected. Overall ADR was 29.5%(men 33.2%, women 23.8%) and overall SSADR was 1.8%(men 1.7%, women 2.1%). In addition, 672 low-grade adenomas (68.8% of all the detected lowgrade adenomas), 58 (69.9%) high-grade adenomas, 29 (34.5%) cancers, 52 (78.8%) SSAs, and 2 (100%) SSAs with cytological dysplasia were found in the proximal colon. Adenoma detection was the only significant predictor of SSA detection (adjusted OR: 2.53, 95%CI: 1.53-4.20; P < 0.001). The correlation coefficient between ADR and SSADR weighted by the number of each gastroenterologist's examinations was 0.606(P < 0.001).CONCLUSION Our results demonstrated that ADR is correlated to SSADR. In addition, patients with adenomas had a higher prevalence of SSAs than those without adenomas. 展开更多
关键词 Sessile serrated ADENOMA Sessile serrated ADENOMA detection RATE ADENOMA detection RATE COLONOSCOPY interval COLORECTAL cancer
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Intraprocedural bowel cleansing with the Jet Prep cleansing system improves adenoma detection
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作者 Arthur Hoffman Sanjay Murthy +5 位作者 Lena Pompetzki Johannes Wilhelm Rey Martin Goetz Achim Tresch Peter Robert Galle Ralf Kiesslich 《World Journal of Gastroenterology》 SCIE CAS 2015年第26期8184-8194,共11页
AIM: To investigate the impact of Jet Prep cleansing on adenoma detection rates.METHODS: In this prospective,randomized,crossover trial,patients were blindly randomized to an intervention arm or a control arm.In accor... AIM: To investigate the impact of Jet Prep cleansing on adenoma detection rates.METHODS: In this prospective,randomized,crossover trial,patients were blindly randomized to an intervention arm or a control arm.In accordance with the risk profile for the development of colorectal carcinoma,the study participants were divided into high-risk and low-risk groups.Individuals with just one criterion(age > 70 years,adenoma in medical history,and first-degree relative with colorectal cancer) were regarded as high-risk patients.Bowel preparation was performed in a standardized manner one day before the procedure.Participants in the intervention arm underwent an initial colonoscopy with standard bowel cleansing using a 250-m L syringe followed by a second colonoscopy that included irrigation by the use of the Jet Prep cleansing system.The reverse sequence was used in the control arm.The study participants were divided into a high-risk group and a low-risk group according to their respective risk profiles for the development of colorectal carcinoma.RESULTS: A total of 64 patients(34 men and 30 women) were included in the study; 22 were included in the high-risk group.After randomization,30 patients were assigned to the control group(group A) and 34 to the intervention group(group B).The average Boston Bowel Preparation Scale score was 5.15 ± 2.04.The withdrawal time needed for the first step was significantly longer in group A using the Jet Prep system(9.41 ± 3.34 min) compared to group B(7.5 ± 1.92 min).A total of 163 polyps were discovered in 64 study participants who underwent both investigation steps.In group A,49.4% of the polyps were detected during the step of standard bowel cleansing while the miss rate constituted 50.7%.Group B underwent cleansing with the Jet Prep system during the first examination step,and as many as 73.9% of polyps were identified during this step.Thus,the miss rate in group B was a mere 26.1%(P < 0.001).When considering only the right side of the colon,the miss rate in group A during the first examination was 60.6%,in contrast to a miss rate of 26.4% in group B(P < 0.001).CONCLUSION: Jet Prep is recommended for use during colonoscopy because a better prepared bowel enables a better adenoma detection,particularly in the proximal colon. 展开更多
关键词 COLON preparation ADENOMA detection RATE ADENOMA miss RATE interval cancer Boston BowelPreparation Scale Right sided COLON Flat ADENOMA
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Outsourced Privacy-Preserving Anomaly Detection in Time Series of Multi-Party
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作者 Chunkai Zhang Wei Zuo +2 位作者 Peng Yang Ye Li Xuan Wang 《China Communications》 SCIE CSCD 2022年第2期201-213,共13页
Anomaly detection has practical significance for finding unusual patterns in time series.However,most existing algorithms may lose some important information in time series presentation and have high time complexity.A... Anomaly detection has practical significance for finding unusual patterns in time series.However,most existing algorithms may lose some important information in time series presentation and have high time complexity.Another problem is that privacy-preserving was not taken into account in these algorithms.In this paper,we propose a new data structure named Interval Hash Table(IHTable)to capture more original information of time series and design a fast anomaly detection algorithm based on Interval Hash Table(ADIHT).The key insight of ADIHT is distributions of normal subsequences are always similar while distributions of anomaly subsequences are different and random by contrast.Furthermore,to make our proposed algorithm fit for anomaly detection under multiple participation,we propose a privacy-preserving anomaly detection scheme named OP-ADIHT based on ADIHT and homomorphic encryption.Compared with existing anomaly detection schemes with privacy-preserving,OP-ADIHT needs less communication cost and calculation cost.Security analysis of different circumstances also shows that OP-ADIHT will not leak the privacy information of participants.Extensive experiments results show that ADIHT can outperform most anomaly detection algorithms and perform close to the best results in terms of AUC-ROC,and ADIHT needs the least time. 展开更多
关键词 anomaly detection interval hash table PRIVACY-PRESERVING multiple participants
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Early Detection of QoE Deterioration in HTTP Adaptive Streaming
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作者 Phan Xuan-Tan Eiji Kamioka 《Journal of Computer and Communications》 2017年第14期14-27,共14页
Apart from video rate (or requested bitrate), Mean Opinion Score (MOS) has increasingly become a primary term representing Quality of Experience (QoE) in HTTP adaptive streaming (HAS). By monitoring this metric, QoE m... Apart from video rate (or requested bitrate), Mean Opinion Score (MOS) has increasingly become a primary term representing Quality of Experience (QoE) in HTTP adaptive streaming (HAS). By monitoring this metric, QoE management can effectively maximize QoE for the users. However, due to various behaviors of particular commercial HAS players, deciding an appropriate monitoring interval has not been fully investigated yet. In this paper, an optimal interval is proposed to be equal to duration of a video chunk in order to aid service managers in early detecting QoE deterioration and limiting the probability of video rate deterioration. The optimal monitoring interval is evaluated by comparing with other values of interval in terms of ratio of video rate deterioration. Furthermore, MOS-based QoE monitoring method which takes into account the proposed interval is thus compared with video rate based monitoring method. The results show that with optimal interval, MOS monitoring guarantees a low ratio of video rate deterioration (around 10% for buffering state and 40% for steady state) and small average CPU Load (about 11.45%). 展开更多
关键词 QOE MOS QoS VIDEO Rate detection Time Optimal Monitoring interval
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基于DBN-IWOA优化的区间二型TSK模糊逻辑系统在化工过程建模中的应用
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作者 李军 康鹏元 《过程工程学报》 北大核心 2026年第1期99-108,共10页
针对化工过程中存在的强非线性和复杂性问题,本工作提出了一种基于深度信念网络(DBN)与改进鲸鱼优化算法(IWOA)优化的区间二型TSK模糊逻辑系统(DBN-IWOA-IT2 TSK FLS)方法,以提升软测量建模的精度和稳定性。首先,DBN通过深度特征提取能... 针对化工过程中存在的强非线性和复杂性问题,本工作提出了一种基于深度信念网络(DBN)与改进鲸鱼优化算法(IWOA)优化的区间二型TSK模糊逻辑系统(DBN-IWOA-IT2 TSK FLS)方法,以提升软测量建模的精度和稳定性。首先,DBN通过深度特征提取能力对输入数据进行处理,以减少噪声干扰并提取关键信息。随后,结合区间二型TSK模糊逻辑系统(IT2 TSK FLS)的建模优势,采用IWOA算法对前件参数和后件参数进行优化,以进一步增强模型的预测能力。IWOA通过引入早熟收敛检测机制,提高了全局搜索能力,加快了收敛速度,并降低了陷入局部最优的风险。最后,将所提出的方法应用于脱丁烷塔软测量建模,选取了支持向量机(SVM)、长短期记忆网络(LSTM)、门控循环单元网络(GRU),以及分别基于反向传播算法(BP)、粒子群优化算法(PSO)、灰狼优化算法(GWO)、鲸鱼优化算法(WOA)、改进鲸鱼优化算法(IWOA)和DBN-IWOA优化算法的区间二型TSK模糊逻辑系统作为对比模型进行实验评估。结果显示,DBN-IWOA-IT2 TSK FLS在预测准确性、收敛速度均优于现有方法,验证了其有效性和工程应用价值。 展开更多
关键词 软测量建模 脱丁烷塔 区间二型模糊逻辑系统 深度置信网络 早熟收敛检测机制
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基于时间区间重叠算法的高校会议管理系统
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作者 陈明 《移动信息》 2026年第2期233-235,共3页
在高校数字化转型背景下,传统的会议管理系统存在资源利用率低、预约繁琐、缺乏可视化等问题。文中基于时间区间重叠算法对高校会议管理系统进行了研究,旨在实现智能预约冲突检测,并引入了设备关联筛选以提升资源匹配度。同时,采用RBAC... 在高校数字化转型背景下,传统的会议管理系统存在资源利用率低、预约繁琐、缺乏可视化等问题。文中基于时间区间重叠算法对高校会议管理系统进行了研究,旨在实现智能预约冲突检测,并引入了设备关联筛选以提升资源匹配度。同时,采用RBAC模型结合JWT实现权限控制,利用ECharts对会议室使用率和预约趋势进行数据可视化,以辅助管理决策,提升资源调度效率与用户体验。 展开更多
关键词 时间区间重叠算法 会议管理 冲突检测
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离散时间模糊Markov跳变系统基于区间观测器的故障检测
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作者 王淑佳 朱淑倩 《聊城大学学报(自然科学版)》 2026年第2期159-170,共12页
针对一类带有执行器故障的离散时间模糊Markov跳变系统,基于区间观测器方法研究有限频域故障检测问题。通过融合系统状态与持续干扰的边界信息,提出模态依赖的模糊区间观测器,构建上下界估计误差增广系统模型并生成动态残差区间,进而分... 针对一类带有执行器故障的离散时间模糊Markov跳变系统,基于区间观测器方法研究有限频域故障检测问题。通过融合系统状态与持续干扰的边界信息,提出模态依赖的模糊区间观测器,构建上下界估计误差增广系统模型并生成动态残差区间,进而分别引入l_(∞)性能指标和H-性能指标来评估残差区间对扰动的鲁棒性和对故障的敏感性。为克服模态转移概率导致的有限频域性能指标设计难题,引入Markov化状态数学期望将误差系统转化为确定性模糊系统,并运用模态依赖的模糊Lyapunov函数方法,分别建立误差系统的l_(∞)性能和H-性能分析结果,进而以线性矩阵不等式形式给出实现有限频域故障检测的区间观测器设计与优化算法。通过数值仿真验证所提算法在故障检测效率上的有效性与优越性。 展开更多
关键词 模糊Markov跳变系统 模糊区间观测器 故障检测 有限频域
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工业监控视频中的跑冒滴漏检测算法研究
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作者 胡耀国 杨青松 +1 位作者 李小波 张青林 《计算机仿真》 2026年第1期302-305,共4页
针对核电站、化工厂等工业场景中管道的跑冒滴漏检测难、成本高等问题,提出一种基于YOLOv8的目标检测算法。首先,利用改进的帧差法对图像进行预处理,从而提升图像质量并降低误报率;然后通过改进的YOLOv8网络结构对管道跑冒滴漏的识别,... 针对核电站、化工厂等工业场景中管道的跑冒滴漏检测难、成本高等问题,提出一种基于YOLOv8的目标检测算法。首先,利用改进的帧差法对图像进行预处理,从而提升图像质量并降低误报率;然后通过改进的YOLOv8网络结构对管道跑冒滴漏的识别,得到检测框A;最后,采用改进的五帧间隔差分法生成检测框B,并通过两个检测框的交集精确定位跑冒滴漏。实验结果证明,通过在某核电站实际验证,上述算法的m AP值相比原始算法提高了29.3%,达到了72.4%。在工程应用中,所提算法不仅精准度有显著提升,而且误报率也从20.6%降至5.4%,充分满足了实际工程应用的需求。 展开更多
关键词 跑冒滴漏 图像处理 五帧间隔差分法
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公务用车预约平台的设计与实现
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作者 孙旭 《现代信息科技》 2026年第4期105-111,共7页
政企单位对公务用车管理日益依赖信息系统。为解决以往研究未设置有效机制检测预约时间段重叠的问题,该研究设计并实现了基于时间区间冲突检测算法的公务用车预约平台。系统采用B/S架构、Spring Boot框架、Java语言和MySQL数据库等开发... 政企单位对公务用车管理日益依赖信息系统。为解决以往研究未设置有效机制检测预约时间段重叠的问题,该研究设计并实现了基于时间区间冲突检测算法的公务用车预约平台。系统采用B/S架构、Spring Boot框架、Java语言和MySQL数据库等开发技术,将用户角色划分为普通用户和管理员,依据角色需求提供相应功能。测试结果表明,系统整体表现稳定、安全、可靠,基本实现了预期功能。平台使员工在线即可预约车辆,提高了车辆的管理效率和利用率,并改善了管理不透明等问题。 展开更多
关键词 公务用车预约 时间区间冲突检测算法 B/S架构 Spring Boot框架 Java语言 MYSQL数据库
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Comparison of Time Interval Statistic and Pulse Shape Discrimination in Fast Neutron Detection Method with Liquid Scintillation Detector Loaded Gd
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作者 Mohammed Adel Al-jumaili Qiang Du +6 位作者 Jingjun Zhu Xinde Lin Wenbin Lin Changjian Tang Mustafa Raad Kadhim Haoyang Xing Shukui Liu 《应用物理前沿(中英文版)》 2017年第1期1-7,共7页
Neutron usually appears with gamma,which is requiring the detector has the capability of n gamma discrimination.Pulse shape discrimination(PSD)is a common approach of n,gamma judgment,but required a complex process to... Neutron usually appears with gamma,which is requiring the detector has the capability of n gamma discrimination.Pulse shape discrimination(PSD)is a common approach of n,gamma judgment,but required a complex process to select a suitable discrimination factor,and poor performance in the low energy range.A method based on the time interval of adjacent Signals was disrupted and adopted to compare to pulse shape discrimination in the fast neutron detection method.A good agreement between the adopted method and PSD method was achieved,including the total count ratio and neutron count ratio.The comparison proves the correctness of the theoretical derivation and validates the method in practice.The advantages and limitations of the method based on time Interval of adjacent signals were analyzed.The method provides an effective way to confirm the calibration of the neutron detection of a liquid scintillation detector.Also,as a simple way only requiring the time information about events,the described method has large application potential in some case of fast neutron flux or intensity measurement. 展开更多
关键词 NEUTRON detection Gd-loaded Liquid Scintillation detectOR Fast-slow Signal Time interval Distribution Pulse Shape DISCRIMINATION
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全部子系统均不稳定切换线性系统的有限时间混合无扰切换故障检测 被引量:1
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作者 梁占红 姚利娜 高金峰 《控制与决策》 北大核心 2025年第5期1705-1713,共9页
研究全部子系统均不稳定切换线性系统在模态依赖区间驻留时间(MDIDT)切换下的有限时间混合无扰切换故障检测滤波器(FDF)设计问题.首先,为了改善故障检测系统的暂态性能,提出一种直接限制切换时刻残差信号和速率信号总颠簸幅度的混合无... 研究全部子系统均不稳定切换线性系统在模态依赖区间驻留时间(MDIDT)切换下的有限时间混合无扰切换故障检测滤波器(FDF)设计问题.首先,为了改善故障检测系统的暂态性能,提出一种直接限制切换时刻残差信号和速率信号总颠簸幅度的混合无扰切换性能描述;然后,通过将驻留时间区间分段,构造保守性更低的时变离散Lyapunov函数,得到增广系统在MDIDT切换下有限时间稳定且满足有限时间H_(∞)性能的充分条件;接着,在此基础上,给出有限时间混合无扰切换FDF的设计条件;最后,通过数值仿真验证所提出方法的有效性和优越性. 展开更多
关键词 切换线性系统 不稳定子系统 无扰切换 故障检测 有限时间稳定 模态依赖区间驻留时间
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一种改进的惯性行人导航零速区间检测算法
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作者 郑涛 彭艳 刘明岳 《大地测量与地球动力学》 北大核心 2025年第12期1234-1239,共6页
在惯性行人导航中,传统固定阈值检测方法常因误检和漏检问题导致行人定位误差显著增大。针对此问题,提出一种改进的零速区间检测算法。该算法首先基于广义似然比检测(GLRT)构建自适应阈值检测模型;然后利用多重约束检测所获取的阈值,剔... 在惯性行人导航中,传统固定阈值检测方法常因误检和漏检问题导致行人定位误差显著增大。针对此问题,提出一种改进的零速区间检测算法。该算法首先基于广义似然比检测(GLRT)构建自适应阈值检测模型;然后利用多重约束检测所获取的阈值,剔除自适应检测中的误检信息,从而提高零速区间的检测精度。为验证算法性能,设计2种实验场景:L形和矩形路线下的常速行走与快速行走。实验结果表明,与加速度幅值方差检测(AMV)和GLRT算法相比,本文算法不仅简单易实现,且参考点的RMSE降低40%以上,显著提升了惯性行人导航的精度。 展开更多
关键词 惯性行人导航 零速区间检测 自适应阈值 多重约束 室内定位
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不同曲率半径弯管的缺陷检测研究及周向损伤定位
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作者 唐东林 梁君吉 +2 位作者 游东潘 覃超 饶胜 《石油机械》 北大核心 2025年第8期125-132,共8页
为了完善对多种管道结构的缺陷检测方法,针对不同曲率半径下的弯管缺陷检测展开研究。从超声导波在空管中的传播理论出发,绘制了0~100 kHz范围内的频散曲线,分析了L(0,2)模态导波在弯头处的模态转换情况,得出损伤回波中包含F(1,1)模态和... 为了完善对多种管道结构的缺陷检测方法,针对不同曲率半径下的弯管缺陷检测展开研究。从超声导波在空管中的传播理论出发,绘制了0~100 kHz范围内的频散曲线,分析了L(0,2)模态导波在弯头处的模态转换情况,得出损伤回波中包含F(1,1)模态和L(0,2)模态,并根据两者在传播速度上的区别对L(0,2)模态回波进行了提取。建立了仿真模型,研究不同曲率半径的弯管上不同位置的缺陷检测效果。研究结果表明:弯管拱腹和两侧处损伤反射回波较弱,缺陷检测难度最大;拱背处会发生能量聚集,缺陷检测较为易行。曲率半径较小的弯管拱腹和拱背处的缺陷对导波都有较高的反射系数,检测效果好;曲率半径较大的弯管则只针对拱背处缺陷有较好的检测效果。基于以上结论,在不同曲率半径的弯管中设置了多种宽度的损伤,提出了一种基于导波在弯管内传播特性的区间最大值法,实现了弯管处的损伤周向定位。所得结果可为弯管的缺陷检测及周向损伤定位提供技术支撑。 展开更多
关键词 弯管缺陷检测 周向损伤定位 超声导波 曲率半径 模态转换 供背 区间最大值法
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2023年全国传染病突发公共卫生事件发现方式特征分析 被引量:1
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作者 笃梦雪 朱可怡 +7 位作者 杨康 孔庆福 高洁 孟玲 陆步来 涂文校 魏雪莹 向妮娟 《疾病监测》 北大核心 2025年第6期745-748,共4页
目的 分析2023年通过突发公共卫生事件管理信息系统报告的传染病突发公共卫生事件发现方式的特征,为提高我国传染病突发公共卫生事件报告质量提出建议。方法 对2023年经突发公共卫生事件管理信息系统报告的传染病突发公共卫生事件相关... 目的 分析2023年通过突发公共卫生事件管理信息系统报告的传染病突发公共卫生事件发现方式的特征,为提高我国传染病突发公共卫生事件报告质量提出建议。方法 对2023年经突发公共卫生事件管理信息系统报告的传染病突发公共卫生事件相关信息进行分析,了解最初获得事件信息的方式。结果 2023年全国传染病突发公共卫生事件主要通过疾病预防控制机构识别(238起,35.47%)、医疗机构发现(205起,30.55%)以及学校报告(161起,23.99%)等方式发现,3种方式共占2023年传染病突发公共卫生事件总数的90.01%。此外,通过智慧化预警信息提示发现32起突发公共卫生事件。2023年全国传染病突发公共卫生事件从首例患者发病至事件发现的时间间隔中位数为6.83(四分位间距:4.19~9.94)d。结论 2023年全国传染病突发公共卫生事件的发现方式呈现出多样化的特征,智慧化预警信息提示的价值正在逐步凸显,为进一步建立健全智慧化多点触发传染病监测预警体系提供了数据支撑。建议优化智慧化监测预警系统,提高信息整合与风险评估能力,以进一步缩短事件发现时间间隔。 展开更多
关键词 突发公共卫生事件 传染病 发现方式 事件发现时间间隔
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