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1.
线阵分裂波束处理技术在水声探测中的应用 总被引：2，自引：0，他引：2
声呐波束形成处理通常输出各个方位上的目标能量信息,利用指向性极大值位置给出目标的大致方位。为了得到更加精确的目标方位估计,需要寻找对目标方位微小变化作出灵敏反应的物理量。分裂波束处理所输出的各个方位二子阵的相位差信息,对方位变化十分灵敏,其测向精度接近于克拉美罗下界,不需增加太大运算量即可显著提高声呐系统测向精度,在水声中得到了广泛研究和应用。对线阵分裂波束处理在水声探测中不同的应用进行了梳理和总结,重点阐述了基于分裂阵半波束处理的被动声呐宽带相关检测、主动声呐相位单元化处理、超波束形成和水下慢速目标相位差空时方差自动检测跟踪(Automatic Detection and Tracking,ADT)技术的原理、处理流程和结果。 相似文献
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Pipeline defect detection systems collect the videos from cameras of pipeline robots, however the systems always analyzed these videos by offline systems or humans to detect the defects of potential security threats. The existing systems tend to reach the limit in terms of data access anywhere, access security and video processing on cloud. There is in need of studying on a pipeline defect detection cloud system for automatic pipeline inspection. In this paper, we deploy the framework of a cloud based pipeline defect detection system, including the user management module, pipeline robot control module, system service module, and defect detection module. In the system, we use a role encryption scheme for video collection, data uploading, and access security, and propose a hybrid information method for defect detection. The experimental results show that our approach is a scalable and efficient defection detection cloud system. 相似文献
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Cloud computing provides easy and on-demand access to computing resources in a configurable pool. The flexibility of the cloud environment attracts more and more network services to be deployed on the cloud using groups of virtual machines (VMs), instead of being restricted on a single physical server. When more and more network services are deployed on the cloud, the detection of the intrusion likes Distributed Denial-of-Service (DDoS) attack becomes much more challenging than that on the traditional servers because even a single network service now is possibly provided by groups of VMs across the cloud system. In this paper, we propose a cloud-based intrusion detection system (IDS) which inspects the features of data flow between neighboring VMs, analyzes the probability of being attacked on each pair of VMs and then regards it as independent evidence using Dempster-Shafer theory, and eventually combines the evidence among all pairs of VMs using the method of evidence fusion. Unlike the traditional IDS that focus on analyzing the entire network service externally, our proposed algorithm makes full use of the internal interactions between VMs, and the experiment proved that it can provide more accurate results than the traditional algorithm. 相似文献
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Yihe Liu Aaqif Afzaal Abbasi Atefeh Aghaei Almas Abbasi Amir Mosavi Shahaboddin Shamshirband Mohammed A. A. Al-qaness 《计算机、材料和连续体（英文）》2020,63(1):31-61
Mobile cloud computing is an emerging field that is gaining popularity across borders at a rapid pace. Similarly, the field of health informatics is also considered as an extremely important field. This work observes the collaboration between these two fields to solve the traditional problem of extracting Electrocardiogram signals from trace reports and then performing analysis. The developed system has two front ends, the first dedicated for the user to perform the photographing of the trace report. Once the photographing is complete, mobile computing is used to extract the signal. Once the signal is extracted, it is uploaded into the server and further analysis is performed on the signal in the cloud. Once this is done, the second interface, intended for the use of the physician, can download and view the trace from the cloud. The data is securely held using a password-based authentication method. The system presented here is one of the first attempts at delivering the total solution, and after further upgrades, it will be possible to deploy the system in a commercial setting. 相似文献
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带直线特征的数字图象的位置检测 总被引：2，自引：0，他引：2
在图象测量及物体精确定位处理中，为了确定被测物体的旋转及平移的偏差量，通过处理被测物体图象的边缘而获得的几何参数，为提高到测量系统的精度，本文提出了一种通过提取图象边缘的直线特征；并对边缘点进行插值和加密的方法，将图象边缘定位于亚象元，利用最小二乘法拟合出直线方程，根据求得的参数，可以确定图象的旋转及平移量。 相似文献
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1 ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｍｍｏｎｌｙ ,ａｇｉｇａｎｔｉｃｃｏｍｐｌｅｘｓｙｓｔｅｍｕｔｉｌｉｚｅｓＦａｕｌｔＴｒｅｅＡｎａｌｙｓｉｓ (ＦＴＡ)ｔｏａｎａｌｙｚｅｉｔｓｒｅｌｉａｂｉｌｉｔｙａｎｄｕｔｉｌｉｚｅｓａｎｕｐｌｉｎｋｏｒｄｏｗｎｌｉｎｋｍｅｔｈｏｄｔｏｏｂｔａｉｎｔｈｅｍｉｎｉｍｕｍｃｕｔｓｅｔｓ.ＹｅｔｉｔｉｓｃｏｍｐｌｅｘｔｏｕｓｅＦＴＡｔｏｂｕｉｌｄａｔｒｅｅａｎｄｉｔｄｅｍａｎｄｓｔｈａｔｔｈｅｂｕｉｌｄｅｒｉｎｔｅｎｓｉｖｅｌｙｒｅａｌｉｚｅａｌｌｃｏｍｐｏｎｅｎｔｓｏ… 相似文献
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Yean‐Ren Hwang 《中国工程学刊》2013,36(5):635-639
Abstract It is well known that using differential geometric methods, the reachability of nonlinear systems can be checked via Lie algebra. Normally, the resultant checking condition is state dependent and requires complicated recursive Lie bracket operations. In this paper, it is shown that for dyadic bilinear systems, the reachability property is actually state independent, and hence a global property of the system. Specifically, it is proved that the Lie algebra condition is equivalent to the rank conditions of two constant matrices. As examples, the reachability of two real‐world systems is examined through the new checking condition. 相似文献
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Yongjie Yang Shanshan Tu Raja Hashim Ali Hisham Alasmary Muhammad Waqas Muhammad Nouman Amjad 《计算机、材料和连续体（英文）》2023,74(1):801-815
With the recent developments in the Internet of Things (IoT), the amount of data collected has expanded tremendously, resulting in a higher demand for data storage, computational capacity, and real-time processing capabilities. Cloud computing has traditionally played an important role in establishing IoT. However, fog computing has recently emerged as a new field complementing cloud computing due to its enhanced mobility, location awareness, heterogeneity, scalability, low latency, and geographic distribution. However, IoT networks are vulnerable to unwanted assaults because of their open and shared nature. As a result, various fog computing-based security models that protect IoT networks have been developed. A distributed architecture based on an intrusion detection system (IDS) ensures that a dynamic, scalable IoT environment with the ability to disperse centralized tasks to local fog nodes and which successfully detects advanced malicious threats is available. In this study, we examined the time-related aspects of network traffic data. We presented an intrusion detection model based on a two-layered bidirectional long short-term memory (Bi-LSTM) with an attention mechanism for traffic data classification verified on the UNSW-NB15 benchmark dataset. We showed that the suggested model outperformed numerous leading-edge Network IDS that used machine learning models in terms of accuracy, precision, recall and F1 score. 相似文献
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Toru Takahashi Tsuyoshi Hamada 《International journal for numerical methods in engineering》2009,80(10):1295-1321
Recently, the application of graphics processing units (GPUs) to scientific computations is attracting a great deal of attention, because GPUs are getting faster and more programmable. In particular, NVIDIA's GPUs called compute unified device architecture enable highly mutlithreaded parallel computing for non‐graphic applications. This paper proposes a novel way to accelerate the boundary element method (BEM) for three‐dimensional Helmholtz' equation using CUDA. Adopting the techniques for the data caching and the double–single precision floating‐point arithmetic, we implemented a GPU‐accelerated BEM program for GeForce 8‐series GPUs. The program performed 6–23 times faster than a normal BEM program, which was optimized for an Intel's quad‐core CPU, for a series of boundary value problems with 8000–128000 unknowns, and it sustained a performance of 167 Gflop/s for the largest problem (1 058 000 unknowns). The accuracy of our BEM program was almost the same as that of the regular BEM program using the double precision floating‐point arithmetic. In addition, our BEM was applicable to solve realistic problems. In conclusion, the present GPU‐accelerated BEM works rapidly and precisely for solving large‐scale boundary value problems for Helmholtz' equation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Abstract Detecting the endocardium and epicardium of the left ventricle is important for further quantitative analysis of cardiac functions and three‐dimensional reconstruction. However, to detect the boundaries automatically is difficult. In this paper, we proposed a novel, single frame method, based on binary morphology and region growing techniques, to detect the boundaries of the left ventricle automatically except an A.O.I. (Area Of Interest) adjustment operation must be performed during the process of getting image data from video tape and storing it onto the disk. The method is suited for boundary detection required in three‐dimensional reconstruction for the observation of congenital abnormalities of ventricular septum or for generating cross sectional images of arbitrary orientation. Moreover, the method may be improved by further processings for accurate endocardial and epicardial boundary estimation for quantitative cardiac function evaluations. 相似文献
12.
Rui Jiang Guoqiang Peng Qijun Li Haoxu Wang Zhipeng Ci Qian Wang 《Advanced Materials Technologies》2024,9(8):2301894
Organic–inorganic hybrid metal halides are widely used in X-ray detection and imaging due to their high X-ray absorption efficiency, ease of synthesis, and efficient luminescence. However, the issue of lead toxicity remains a concern. In this study, non-toxic, 0D 2,2′-(Ethylenedioxy)bis(ethylamine) manganese (II) bromide (EDBEMnBr4) is synthesized using the simple mechanical grinding method and the solution method that exhibits intense green emission at ≈525 nm. Moreover, the change of structure under the influence of temperature and water significantly affects its fluorescence color under UV light. Scintillator materials with and without moisture exposure showed spatial resolutions of 7 and 4 lp mm−1, and low detection limits of 4.62 and 5.25 µGyair s−1, respectively, meeting medical industry standards (<5.5 µGyair s−1). Furthermore, based on the apparent change in luminescence color triggered by moisture for EDBEMnBr4, a preliminary attempt is made to apply it to humidity monitoring showing that the boundary of color change has a good linear dependence on humidity and time. This work provides new opportunities for Mn-based metal halides in both X-ray detection as well as moisture detection. 相似文献
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一种无衍射激光图像亚像素边缘检测方法 总被引：1，自引：2，他引：1
为进一步提高无衍射激光图像的定中精度,提出了一种亮环亚像素级边缘点检测方法.首先,采用局域亮度最大方法,提取亮环像素级屋脊边缘点;然后,利用线性插值算法对每一像素级边缘点进行亚像素处理进而获得亚像素边缘点;最后,用最小二乘方法,将亚像素边缘点拟合定中.分别对距离光源40 m、50 m、60 m处,各连续拍摄的50幅图像(图像分辨率为640×480,光靶分辨率为0.057 2 mm/pixel)进行了处理,各位置处的亚像素级边缘点x方向定中标准差分别为0.021 4 nm、0.037 2 mm和0.042 3mm,y方向定中标准差分别为0.022 8 mm、0.035 1 mm和0.043 7 mm,明显优于像素级边缘点,实验结果表明,该方法切实可行. 相似文献
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基于小波的多尺度SUSAN角点检测 总被引：1，自引：0，他引：1
SUSAN角点检测是一种经典的角点检测算法,但不具有尺变化特性.利用小波变换的多尺度特性,即在小尺度下的定位准确和大尺度下的抗噪性强,该文把多分辨分析的思想引入到该算法中,从而构建了一种新的基于小波变换的SUSAN多尺度角点检测算法.新的角点检测可以在不同的尺度下获取角点,克服了单一尺度的SUSAN角点检测可能存在的角点位置偏移和易受噪声干扰而提取出伪角点等问题.为了综合利用各个尺度下的角点信息,该文提出了由粗到细的角点筛选方案.通过对比实验,新算法明显地提高了图像角点检测性能. 相似文献
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在企业产品质量检测中,图像处理技术已经发挥着越来越重要的作用.现针对工业流水线上在线缺陷检测系统中的图像处理单元,对胶囊图像采用改进的中值滤波算法、双峰直方图法、形态学操作、Hough直线检测等方法进行处理,得到胶囊的面积、周长,胶囊壁的长度,胶囊两端圆弧的近似长度等特征参数,进而达到识别胶囊外形是否合格的目的. 相似文献
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Aiming at the detection of the sucker rod defects, a real-time detection system is designed using the non-destructive testing technology of magnetic flux leakage (MFL). An MFL measurement system consists of many parts, and this study focuses on the signal acquisition and processing system. First of all, this paper introduces the hardware part of the acquisition system in detail, including the selection of the Hall-effect sensor, the design of the signal conditioning circuit, and the working process of the single chip computer (SCM) control serial port. Based on LabVIEW, a graphical programming software, the software part of the acquisition system is written, including serial port parameter configuration, detection signal recognition, original signal filtering, real-time display, data storage and playback. Finally, an experimental platform for the MFL detection is set up, and the MFL measurement is carried out on the transverse and longitudinal defects of the sucker rod surface. The experimental result shows that the designed acquisition and processing system has good detection performance, simple design and high flexibility. 相似文献
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With the rapid development of mobile Internet and finance technology, online e-commerce transactions have been increasing and expanding very fast, which globally brings a lot of convenience and availability to our life, but meanwhile, chances of committing frauds also come in all shapes and sizes. Moreover, fraud detection in online e-commerce transactions is not totally the same to that in the existing areas due to the massive amounts of data generated in e-commerce, which makes the fraudulent transactions more covertly scattered with genuine transactions than before. In this article, a novel scalable and comprehensive approach for fraud detection in online e-commerce transactions is proposed with majorly four logical modules, which uses big data analytics and machine learning algorithms to parallelize the processing of the data from a Chinese e-commerce company. Groups of experimental results show that the approach is more accurate and efficient to detect frauds in online e-commerce transactions and scalable for big data processing to obtain real-time property. 相似文献
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