To see the other types of publications on this topic, follow the link: Inspection computation.
Journal articles on the topic 'Inspection computation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Inspection computation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Rau, Hsin, Kuo Hua Cho, and Yi Hsiang Wang. "Optimal Inspection Allocation for Workstations of Attribute Data with Multi-Characteristics in Multi-Station Systems." Key Engineering Materials 450 (November 2010): 397–400. http://dx.doi.org/10.4028/www.scientific.net/kem.450.397.
Full textAbstract:
. The study models multi-characteristics inspection for inspection allocation problems with workstations of attribute data in serial production systems. Either 100% or 0% inspection is performed and Type I and Type II errors are considered. In addition, this study considers three possibilities of treatment of detected nonconforming units, namely, repair, rework and scrap. With the above considerations, a profit model is developed for optimally allocating inspections. Moreover, a genetic algorithm is used to solve the problem and it is proved to have much less computation time, compared with an optimization method based on complete enumeration, especially when number of workstations and characteristics becomes more.
2
Zou, Guang, Kian Banisoleiman, and Arturo González. "Bayesian maintenance decision optimisation based on computing the information value from condition inspections." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 235, no. 4 (March 26, 2021): 545–55. http://dx.doi.org/10.1177/1748006x20978127.
Full textAbstract:
A challenge in marine and offshore engineering is structural integrity management (SIM) of assets such as ships, offshore structures, mooring systems, etc. Due to harsh marine environments, fatigue cracking and corrosion present persistent threats to structural integrity. SIM for such assets is complicated because of a very large number of rewelded plates and joints, for which condition inspections and maintenance are difficult and expensive tasks. Marine SIM needs to take into account uncertainty in material properties, loading characteristics, fatigue models, detection capacities of inspection methods, etc. Optimising inspection and maintenance strategies under uncertainty is therefore vital for effective SIM and cost reductions. This paper proposes a value of information (VoI) computation and Bayesian decision optimisation (BDO) approach to optimal maintenance planning of typical fatigue-prone structural systems under uncertainty. It is shown that the approach can yield optimal maintenance strategies reliably in various maintenance decision making problems or contexts, which are characterized by different cost ratios. It is also shown that there are decision making contexts where inspection information doesn’t add value, and condition based maintenance (CBM) is not cost-effective. The CBM strategy is optimal only in the decision making contexts where VoI > 0. The proposed approach overcomes the limitation of CBM strategy and highlights the importance of VoI computation (to confirm VoI > 0) before adopting inspections and CBM.
3
Huang, Yibin, Congying Qiu, Xiaonan Wang, Shijun Wang, and Kui Yuan. "A Compact Convolutional Neural Network for Surface Defect Inspection." Sensors 20, no. 7 (April 1, 2020): 1974. http://dx.doi.org/10.3390/s20071974.
Full textAbstract:
The advent of convolutional neural networks (CNNs) has accelerated the progress of computer vision from many aspects. However, the majority of the existing CNNs heavily rely on expensive GPUs (graphics processing units). to support large computations. Therefore, CNNs have not been widely used to inspect surface defects in the manufacturing field yet. In this paper, we develop a compact CNN-based model that not only achieves high performance on tiny defect inspection but can be run on low-frequency CPUs (central processing units). Our model consists of a light-weight (LW) bottleneck and a decoder. By a pyramid of lightweight kernels, the LW bottleneck provides rich features with less computational cost. The decoder is also built in a lightweight way, which consists of an atrous spatial pyramid pooling (ASPP) and depthwise separable convolution layers. These lightweight designs reduce the redundant weights and computation greatly. We train our models on groups of surface datasets. The model can successfully classify/segment surface defects with an Intel i3-4010U CPU within 30 ms. Our model obtains similar accuracy with MobileNetV2 while only has less than its 1/3 FLOPs (floating-point operations per second) and 1/8 weights. Our experiments indicate CNNs can be compact and hardware-friendly for future applications in the automated surface inspection (ASI).
4
Pfingstl, Simon, Martin Steiner, Olaf Tusch, and Markus Zimmermann. "Crack Detection Zones: Computation and Validation." Sensors 20, no. 9 (April 30, 2020): 2568. http://dx.doi.org/10.3390/s20092568.
Full textAbstract:
During the development of aerospace structures, typically many fatigue tests are conducted. During these tests, much effort is put into inspections in order to detect the onset of failure before complete failure. Strain sensor data may be used to reduce inspection effort. For this, a sufficient number of sensors need to be positioned appropriately to collect the relevant data. In order to minimize cost and effort associated with sensor positioning, the method proposed here aims at minimizing the number of necessary strain sensors while positioning them such that fatigue-induced damage can still be detected before complete failure. A suitable detection criterion is established as the relative change of strain amplitudes under cyclic loading. Then, the space of all possible crack lengths is explored. The regions where the detection criterion is satisfied before complete failure occurs are assembled into so-called detection zones. One sensor in this zone is sufficient to detect criticality. The applicability of the approach is demonstrated on a representative airplane structure that resembles a lower wing section. The method shows that four fatigue critical spots can be monitored using only one strain sensor in a non-intuitive position. Furthermore, we discuss two different strain measures for crack detection. The results of this paper can be used for reliable structural health monitoring using a minimum number of sensors.
5
Pathmakumar, Thejus, Vinu Sivanantham, Saurav Ghante Anantha Padmanabha, Mohan Rajesh Elara, and Thein Than Tun. "Towards an Optimal Footprint Based Area Coverage Strategy for a False-Ceiling Inspection Robot." Sensors 21, no. 15 (July 30, 2021): 5168. http://dx.doi.org/10.3390/s21155168.
Full textAbstract:
False-ceiling inspection is a critical factor in pest-control management within a built infrastructure. Conventionally, the false-ceiling inspection is done manually, which is time-consuming and unsafe. A lightweight robot is considered a good solution for automated false-ceiling inspection. However, due to the constraints imposed by less load carrying capacity and brittleness of false ceilings, the inspection robots cannot rely upon heavy batteries, sensors, and computation payloads for enhancing task performance. Hence, the strategy for inspection has to ensure efficiency and best performance. This work presents an optimal functional footprint approach for the robot to maximize the efficiency of an inspection task. With a conventional footprint approach in path planning, complete coverage inspection may become inefficient. In this work, the camera installation parameters are considered as the footprint defining parameters for the false ceiling inspection. An evolutionary algorithm-based multi-objective optimization framework is utilized to derive the optimal robot footprint by minimizing the area missed and path-length taken for the inspection task. The effectiveness of the proposed approach is analyzed using numerical simulations. The results are validated on an in-house developed false-ceiling inspection robot—Raptor—by experiment trials on a false-ceiling test-bed.
6
SÖDERGÅRD, CAJ, RAIMO LAUNONEN, and JUUSO ÄIKÄS. "INSPECTION OF COLOUR PRINTING QUALITY." International Journal of Pattern Recognition and Artificial Intelligence 10, no. 02 (March 1996): 115–28. http://dx.doi.org/10.1142/s0218001496000104.
Full textAbstract:
The use of machine vision technology is being investigated at VTT for improving the colour quality and productivity of web offset printing. The visual inspection of colour quality is performed by a colour CCD camera which traverses the moving web under a stroboscopic light. The measuring locations and goal values for the colour register, the ink density and the grey balance are automatically determined from the PostScript™ description of the digital page. A set of criteria is used to find the most suitable spots for the measurements. In addition to providing data for on-line control, the page analysis estimates the zone wise link consumption of the printing plates as a basis for presetting the ink feed. Target calorimetric CIE-values for grey balance and critical colours are determined from the image originals. The on-line measurement results and their derivations from the target values are displayed in an integrated manner. The paper gives test results of computation times, measurements of register error with and without test targets and the colour measuring capabilities of the system. The results show that machine vision can be used for on-line inspection of colour print quality. This makes it possible to upgrade older printing presses to produce a colour quality that is competitive with more modern presses.
7
Li, Guoyi, Chao Feng, Addishiwot Woldesenbet, Bruce King, Hamid Hadavi, Vikasini Moku, Kurt Loken, and Gary Kunkel. "Deep Learning based Optical Inspection with Centralized Analysis for High Volume Smart Manufacturing." Annual Conference of the PHM Society 12, no. 1 (November 3, 2020): 9. http://dx.doi.org/10.36001/phmconf.2020.v12i1.1282.
Full textAbstract:
Increased capabilities in data storage and exploration provide significant insights for quality assurance in a high volume manufacturing environment. However, these opportunities are associated with great challenges in analytical model development, application deployment, system throughput and reliability. While no commercial software system fully meets the needs of recording head factories in Seagate, a novel strategy named optical inspection with centralized analysis has been developed to detect defects of trailing edges of the recording heads of hard disk drives, and fail the parts when necessary. Leveraging the state-of-the-art artificial intelligence technologies, a deep learning based semantic segmentation engine is built using convolutional neural networks for optical inspection. It has shown an improved accuracy to that of visual inspection performed by human. Meanwhile, a high performance computation engine has been built as a Kubernetes cluster with multiple GPU and CPU units. It is able to achieve the target throughput of three million high-resolution images in each day (i.e., 12 TB image data and 35 images per second). With the high fidelity offered by Kubernetes cluster, the developed applications (inference engine, preprocessor, postprocessor, etc.) serve as containerized microservices independently. Such an architecture ensures the vertical and horizontal scalabilities according to the computation of each individual deployment, while all deployments communicate through an Advanced Message Queuing Protocol cluster without human interference. This analytic framework enables Industry 4.0 recording head manufacturing by integrating advanced AI technologies with a robust edge computation architecture.
8
Lin, Chaochao, and Matteo Pozzi. "Optimal adaptive inspection and maintenance for redundant systems." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 235, no. 4 (May 26, 2021): 568–79. http://dx.doi.org/10.1177/1748006x211020151.
Full textAbstract:
Optimal exploration of engineering systems can be guided by the principle of Value of Information (VoI), which accounts for the topological important of components, their reliability and the management costs. For series systems, in most cases higher inspection priority should be given to unreliable components. For redundant systems such as parallel systems, analysis of one-shot decision problems shows that higher inspection priority should be given to more reliable components. This paper investigates the optimal exploration of redundant systems in long-term decision making with sequential inspection and repairing. When the expected, cumulated, discounted cost is considered, it may become more efficient to give higher inspection priority to less reliable components, in order to preserve system redundancy. To investigate this problem, we develop a Partially Observable Markov Decision Process (POMDP) framework for sequential inspection and maintenance of redundant systems, where the VoI analysis is embedded in the optimal selection of exploratory actions. We investigate the use of alternative approximate POMDP solvers for parallel and more general systems, compare their computation complexities and performance, and show how the inspection priorities depend on the economic discount factor, the degradation rate, the inspection precision, and the repair cost.
9
Li, Xiong Bing, Hong Wei Hu, Ling Li, and Lin Jin Tong. "Data Compression in Automatic Ultrasonic Inspection Based on Lifting Scheme." Applied Mechanics and Materials 48-49 (February 2011): 353–56. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.353.
Full textAbstract:
In this paper, the method of data compression in ultrasonic automatic inspection using integral wavelet transform is proposed. The compression method presented is performed through signal decomposition, thresholding of wavelet transform coefficients, signal reconstruction, evaluating and optimizing algorithm performance by parameters index . The experiments show that the method has the advantages of low computation complexity， fast compression rate， high compression ratio and small reconstruction difference when it is applied to A-Wave data compression.
10
HARIKRISHNAN, K. P., G. AMBIKA, and R. MISRA. "AN ALGORITHMIC COMPUTATION OF CORRELATION DIMENSION FROM TIME SERIES." Modern Physics Letters B 21, no. 02n03 (January 30, 2007): 129–38. http://dx.doi.org/10.1142/s0217984907012517.
Full textAbstract:
We present an algorithmic scheme to compute the correlation dimension D2 of a time series, without requiring the visual inspection of the scaling region in the correlation sum. It is based on the standard Grassberger–Proccacia [GP] algorithm for computing D2. The scheme is tested using synthetic data sets from several standard chaotic systems as well as by adding noise to low-dimensional chaotic data. We show that the scheme is efficient with a few thousand data points and is most suitable when a nonsubjective comparison of D2 values of two time series is required, such as, in hypothesis testing.
11
Imran, Muhammad, Shehnaz Akhter, and Muhammad Kamran Jamil. "Computation of Topological Indices of NEPS of Graphs." Complexity 2021 (June 14, 2021): 1–6. http://dx.doi.org/10.1155/2021/9911226.
Full textAbstract:
The inspection of the networks and graphs through structural properties is a broad research topic with developing significance. One of the methods in analyzing structural properties is obtaining quantitative measures that encode data of the whole network by a real quantity. A large quantity of graph-associated numerical invariants has been used to examine the whole structure of networks. In this analysis, degree-related topological indices have a significant place in nanotechnology and theoretical chemistry. Thereby, the computation of indices is one of the successful branches of research. The noncomplete extended p -sum NEPS of graphs is a famous general graph product. In this paper, we investigated the exact formulas of general zeroth-order Randić, Randić, and the first multiplicative Zagreb indices for NEPS of graphs.
12
MADANAT, Samer M., Pablo L. DURANGO, and Vincent M. GUILLAUMOT. "INSPECTION, PREDICTION AND DECISION-MAKING IN INFRASTRUCTURE MANAGEMENT: FRAME-WORK, MODELS AND COMPUTATION." Doboku Gakkai Ronbunshu, no. 744 (2003): 1–10. http://dx.doi.org/10.2208/jscej.2003.744_1.
Full text
13
Ouyang, Ling, and Dong Yun Wang. "An Adaptive Segmentation Algorithm Based on Threshold Surface." Advanced Materials Research 424-425 (January 2012): 1287–92. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.1287.
Full textAbstract:
In an online defects inspection system for cord fabric based on machine vision, Image segmentation for cord fabric defects has been the heat and difficult problem. An adaptive segmentation algorithm using threshold surface is presented in this paper. This method inspects defects through detecting the change of image gray levels caused by the difference in optic character between glass and defects. The experiment results indicate that the proposed method has low computation cost, fast speed and good segmentation performance. It is in accord with the requirements of online inspection system such as reliability, real-time, and veracity
14
Maistrenko, Andrey, Konstantin Maistrenko, and Anatoliy Svetlakov. "Dichotomy. Dichotomy? Dichotomy! Basic provisions, problems of terminology and inspection analysis of the method of dichotomy." Science Bulletin of the Novosibirsk State Technical University, no. 4 (December 18, 2020): 93–110. http://dx.doi.org/10.17212/1814-1196-2020-4-93-110.
Full textAbstract:
When creating modern systems of automatic control of various processes and objects operating in real time, very often one has to face the problem of solving various kinds of nonlinear scalar equations. Currently, there are a number of computational methods and algorithms for its solution, one of which is the dichotomy method. This method has a number of advantages in comparison with other known methods for solving nonlinear equations, but at present it has not found wide practical use. The main reason for its low popularity is the low rate of convergence of the sequence of approximate solutions and a large amount of computation required to obtain sufficiently accurate solutions. The purpose of the study is to consider in detail distinctive features of the dichotomy method and show the preference of its use in comparison with other known methods. We propose a modified version of the dichotomy method that allows one to obtain more rapidly converging sequences of approximate solutions to nonlinear scalar equations and requires significantly fewer computations required to obtain solutions with the desired accuracy. By solving a number of specific nonlinear equations, it is possible to illustrate the higher convergence rate of the sequence of approximate solutions calculated using the modified dichotomy method and, thereby, to substantiate the advantage of the new method for its use in creating various automatic control and regulation systems. Based on the results obtained a modification of the method for segment bisection is proposed. It has all the main advantages of the modified method. The research results can be used in the development of modern automatic control systems for various technological processes and objects.
15
Nakanishi, Hiroaki, and Hiroyuki Hashimoto. "AR-Marker/IMU Hybrid Navigation System for Tether-Powered UAV." Journal of Robotics and Mechatronics 30, no. 1 (February 20, 2018): 76–85. http://dx.doi.org/10.20965/jrm.2018.p0076.
Full textAbstract:
Electrically powered unmanned aerial vehicles (UAV) are useful in performing inspection at various infrastructures or plants. A power supply through a tether cable is effective in extending flight time. During inspection activities, some or all satellites may be occluded. UAVs for inspection must be operated even in GPS-denied areas; therefore, a navigation system for GPS-denied areas is required. Depth information cannot be obtained correctly by a monocular camera. The ARToolkit, which is widely applied in augmented reality (AR), is not sufficient as a UAV navigation system. We have proposed a hybrid navigation method that integrates the ARToolkit and an inertial measurement unit (IMU). An analytic solution for both the worst and best estimation of yaw angle can be obtained by simple computation and helps remove outliers in measurements. From experimental results, it was proven that position estimation using the proposed method corresponded reasonably; however, it was necessary to correct the difference between the camera origin and the body’s center of gravity.
16
Аверченков, Владимир, Vladimir Averchenkov, Александр Самсоненко, and Aleksandr Samsonenko. "AUTOMATION OF OPTIC INSPECTION CONTROL AT QUALITY MANAGEMENT OF PRINTED CIRCUIT ASSEMBLY SOLDERING." Bulletin of Bryansk state technical university 2016, no. 2 (June 30, 2016): 149–55. http://dx.doi.org/10.12737/20271.
Full textAbstract:
The development of methods of designing and assembling electronic units on circuit boards with the use of surface assembling techniques (SAT) became one of the priority fields. The product optic control is the most common method of control carried out by specialized equipment, an automated optic inspection (AOI). On the basis of the fulfilled analysis of technical solutions on the organization of inspections of different manufacturers and according to the test results in practice of some variants there was offered a circuit including the following equipment layout: a set of chambers, a system of linear displacement, a controller, a computer and software.
The optical inspection software can be divided into the software of management and the software of control. The former serves for the computation of a control signal, the comparison of coordinates of equipment (with physical (F), imported (C) and in-spected (P)) interpretation of coordinates, interpolation and so on. The software of control contains modules: of data import from Gerberfile, the identification of board images obtained from the chamber, of the com-putation and comparison of identified components with a standard, of the analysis defects and the definition of a defect type, of database (DB) filling, of the interaction with a user.
The system described in comparison with foreign analogues has a smaller set of options, but solves a problem of control under conditions of enterprises manufacturing electronics of the second class (according to IPCA-610 Standard “Criteria for Electronic Assemblage Acceptance).
17
Yinka-Banjo, Chika, Isaac O. Osunmakinde, and Antoine Bagula. "Cooperative Behaviours with Swarm Intelligence in Multirobot Systems for Safety Inspections in Underground Terrains." Mathematical Problems in Engineering 2014 (2014): 1–20. http://dx.doi.org/10.1155/2014/678210.
Full textAbstract:
Underground mining operations are carried out in hazardous environments. To prevent disasters from occurring, as often as they do in underground mines, and to prevent safety routine checkers from disasters during safety inspection checks, multirobots are suggested to do the job of safety inspection rather than human beings and single robots. Multirobots are preferred because the inspection task will be done in the minimum amount of time. This paper proposes a cooperative behaviour for a multirobot system (MRS) to achieve a preentry safety inspection in underground terrains. A hybrid QLACS swarm intelligent model based on Q-Learning (QL) and the Ant Colony System (ACS) was proposed to achieve this cooperative behaviour in MRS. The intelligent model was developed by harnessing the strengths of both QL and ACS algorithms. The ACS optimizes the routes used for each robot while the QL algorithm enhances the cooperation between the autonomous robots. A description of a communicating variation within the QLACS model for cooperative behavioural purposes is presented. The performance of the algorithms in terms of without communication, with communication, computation time, path costs, and the number of robots used was evaluated by using a simulation approach. Simulation results show achieved cooperative behaviour between robots.
18
Benouis, Mohamed, Leandro D. Medus, Mohamed Saban, Abdessattar Ghemougui, and Alfredo Rosado-Muñoz. "Food Tray Sealing Fault Detection in Multi-Spectral Images Using Data Fusion and Deep Learning Techniques." Journal of Imaging 7, no. 9 (September 16, 2021): 186. http://dx.doi.org/10.3390/jimaging7090186.
Full textAbstract:
A correct food tray sealing is required to preserve food properties and safety for consumers. Traditional food packaging inspections are made by human operators to detect seal defects. Recent advances in the field of food inspection have been related to the use of hyperspectral imaging technology and automated vision-based inspection systems. A deep learning-based approach for food tray sealing fault detection using hyperspectral images is described. Several pixel-based image fusion methods are proposed to obtain 2D images from the 3D hyperspectral image datacube, which feeds the deep learning (DL) algorithms. Instead of considering all spectral bands in region of interest around a contaminated or faulty seal area, only relevant bands are selected using data fusion. These techniques greatly improve the computation time while maintaining a high classification ratio, showing that the fused image contains enough information for checking a food tray sealing state (faulty or normal), avoiding feeding a large image datacube to the DL algorithms. Additionally, the proposed DL algorithms do not require any prior handcraft approach, i.e., no manual tuning of the parameters in the algorithms are required since the training process adjusts the algorithm. The experimental results, validated using an industrial dataset for food trays, along with different deep learning methods, demonstrate the effectiveness of the proposed approach. In the studied dataset, an accuracy of 88.7%, 88.3%, 89.3%, and 90.1% was achieved for Deep Belief Network (DBN), Extreme Learning Machine (ELM), Stacked Auto Encoder (SAE), and Convolutional Neural Network (CNN), respectively.
19
Liao, Qingmiao, Jianjun Yang, and Yong Zhou. "Sustainable Scheduling of an Automatic Pallet Changer System by Multi-Objective Evolutionary Algorithm with First Piece Inspection." Sustainability 11, no. 5 (March 12, 2019): 1498. http://dx.doi.org/10.3390/su11051498.
Full textAbstract:
In this study, the machining center with the Automated Pallet Changer (APC) scheduling problem considering the disturbance of the first piece inspection is presented. The APC is frequently used in industry practice; it is useful in terms of sustainability and robustness because it increases the machine utilization rate and enhances the responsiveness to uncertainties in dynamic environments. An enhanced evolutionary algorithm for APC scheduling (APCEA) is developed by combining the multi-objective evolutionary algorithm with APC simulation. The dynamic factors in the simulation model include the pass rate of the first piece inspection (FPI) and the adjusted time when the FPI is unpassed. The proposed APCEA defines the non-robust gene based on the risk combination of the first piece inspection, and screens the non-robust gene in the genetic operation, thus improving the solution quality under the same computation times. Compared with the other three multi-objective evolutionary algorithms (MOEAs), it is demonstrated that the proposed APCEA produces the best result among the four methods. The proposed APCEA has been embedded into the manufacturing execution system (MES) and successfully applied in a manufacturing plant. The application value of the proposed method is verified by a practical example.
20
Adli, Adam, and Pascal Tyrrell. "Impact of Training Sample Size on the Effects of Regularization in a Convolutional Neural Network-based Dental X-ray Artifact Prediction Model." Journal of Undergraduate Life Sciences 14, no. 1 (December 31, 2020): 5. http://dx.doi.org/10.33137/juls.v14i1.35883.
Full textAbstract:
Introduction: Advances in computers have allowed for the practical application of increasingly advanced machine learning models to aid healthcare providers with diagnosis and inspection of medical images. Often, a lack of training data and computation time can be a limiting factor in the development of an accurate machine learning model in the domain of medical imaging. As a possible solution, this study investigated whether L2 regularization moderate s the overfitting that occurs as a result of small training sample sizes.Methods: This study employed transfer learning experiments on a dental x-ray binary classification model to explore L2 regularization with respect to training sample size in five common convolutional neural network architectures. Model testing performance was investigated and technical implementation details including computation times and hardware considerations as well as performance factors and practical feasibility were described.Results: The experimental results showed a trend that smaller training sample sizes benefitted more from regularization than larger training sample sizes. Further, the results showed that applying L2 regularization did not apply significant computational overhead and that the extra rounds of training L2 regularization were feasible when training sample sizes are relatively small.Conclusion: Overall, this study found that there is a window of opportunity in which the benefits of employing regularization can be most cost-effective relative to training sample size. It is recommended that training sample size should be carefully considered when forming expectations of achievable generalizability improvements that result from investing computational resources into model regularization.
21
Marzani, Alessandro, Marco Miniaci, and Erasmo Viola. "Effect of an Internal Open Crack on Pipes Wave Propagation." Key Engineering Materials 488-489 (September 2011): 375–78. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.375.
Full textAbstract:
Stress guided waves in the sonic and ultrasonic regime are acknowledged as a powerful too lto inspect pipes in a non-invasive manner.A key point of the inspection procedure is related to the dispersive behavior of guided waves, that for agiven pipe is defined by the so-called dispersion curves. Such behavior, is generally predicted bymeans ofanalytical formulations. However, when the geometry of the pipe cross-section is not axially symmetric,such as in the presence of an open internal crack running along the pipe length, analytical formulations fail. Here, the computation of the guided waves properties for such a scenario is addressed via a SemiAnalytical Finite Element (SAFE) formulation in which the open crack is modeled at the mesh level.Different crack depths are considered and their effect on the waves dispersion curves are highlighted.The results could be of interest in pipeline inspection and monitoring.
22
Ur Rehman, Shams, Ka Fei Thang, and Nai Shyan Lai. "Automated PCB identification and defect-detection system (APIDS)." International Journal of Electrical and Computer Engineering (IJECE) 9, no. 1 (February 1, 2019): 297. http://dx.doi.org/10.11591/ijece.v9i1.pp297-306.
Full textAbstract:
Ever growing PCB industry requires automation during manufacturing process to produce defect free products. Machine Vision is widely used as popular means of inspection to find defects in PCBs. However, it is still largely dependent on user input to select algorithm set for the PCB under inspection prior to the beginning of the process. Continuous increase in computation power of computers and image quality of image acquisition devices demands new methods for further automation. This paper proposes a new method to achieve further automation by identifying the type of PCB under inspection prior to begin defect inspection process. Identification of PCB is achieved by using local feature detectors SURF and ORB and using the orientation data acquired to transform the PCB image to the reference image for inspection of defects. A close-loop system is produced as a prototype to reflect the practicality of the idea. A Graphical User Interface was developed using MATLAB to present the proposed system. Test data contained 29 PCBs. Each PCB was tested 5 times for camera acquired images and 3 times for database images. The identification accuracy is 98.66% for database images and 100% for images acquired from the camera. The time taken to detect the model of PCB is recorded and is significantly lower for ORB based identification than SURF based. The system is also a close loop system which detects defects in PCB units. The detection of defects has highest accuracy of 92.3% for best controlled environment scenario. With controlled environment, the system could detect defects in PCB pertaining to smallest of components such as SMDs.
23
Kirkemo, Finn. "Applications of Probabilistic Fracture Mechanics to Offshore Structures." Applied Mechanics Reviews 41, no. 2 (February 1, 1988): 61–84. http://dx.doi.org/10.1115/1.3151882.
Full textAbstract:
For offshore structures the fatigue limit state is governing the structural dimensions of several members and joint connections. Safety against fatigue failure is achieved through a combination of design requirements and performance of in-service inspections with repair of detected fatigue cracks. A review of uncertainties involved in fatigue life predictions by fracture mechanics is presented with particular reference to steel structures. Sources of uncertainties considered are: environmental conditions, hydrodynamic loading, global structural analysis, local stress calculation at fatigue sensitive points, and fatigue crack growth modeling by fracture mechanics. A probabilistic model using the fracture mechanics in probabilistic form is presented. This model accounts for uncertainties in loading, initial and critical defect sizes, material parameters, and in the uncertainty related to computation of the stress intensity factor. Failure probabilities are computed by first-order reliability methods and sensitivity factors are determined. Model updating based on in-service inspection results is formulated. Uncertainties with respect to detecting a crack and to correctly sizing a crack are included. Experience on application of the analysis method is presented.
24
Zhou, Daocheng, Yan Yu, Jie Wang, and Zhirui Li. "Design and validation of a fast wireless low-frequency vibration inspection system for offshore platform structures." Journal of Low Frequency Noise, Vibration and Active Control 39, no. 3 (April 11, 2019): 720–28. http://dx.doi.org/10.1177/1461348419841252.
Full textAbstract:
Structural health monitoring has become increasingly important in the effective evaluation of structural health conditions and the maintenance service of structures. The validity and convenience of obtaining sensor data are critical for data mining, feature extraction, and condition assessment. A fast wireless low-frequency vibration inspection system (FWLVIS) based on wireless sensor networks for offshore platform structural vibration inspection is presented in this paper. The designed system consists of intelligent acquisition equipment and eight wireless nodes with low-frequency acceleration sensors, while the entire system has 64 collection channels. The wireless nodes integrated with a vibration sensing unit, an embedded low-power micro-processing unit, a wireless transceiver unit, and a large-capacity power unit perform functions, which could perform data collection, initial analysis, data storage, and wireless transmission. The intelligent acquisition equipment integrated with a high-performance computation unit, a wireless transceiver unit, a mobile power source, and the embedded data analysis software could completely control the multi-wireless nodes, receive and analyze the data, and implement the parameter identification. Experiments are performed on a single pendulum, and then on an offshore platform model is constructed to verify the FWLVIS. The experimental results show that the system has the following characteristics: fast arrangement, high sampling rate, high resolution, and capacity for low-frequency inspection. Thus, the system has good application prospects and practical value in the field of structural health monitoring and non-destructive inspection.
25
Kim, Hyung Tae, and Kyung Chan Jin. "Multi-Application and Large Shared Memory in a Mechatronic System for Massive Computation." Applied Mechanics and Materials 307 (February 2013): 18–22. http://dx.doi.org/10.4028/www.scientific.net/amm.307.18.
Full textAbstract:
Recent mechatronic systems, such as inspection machines or 3D imaging apparatuses, acquire and compute massive data for final results. A host in the mechatronic system is commonly composed of multiple hardware devices which interface with high-speed external signals. The host and the devices usually have large memory, so efficient data management is important due to data storage and transfer. In our software structure, each device is managed by respective application and large shared memory (LSM) is allocated in the host for the massive data. The shared memory is accessible from the device applications. Actions of the mechatronic system are driven by combining and broadcasting events through and inter-process communication (IPC). The model with LSM and IPC was applied to a 3D RF imaging system. We expect the proposed model can also be applied to machine vision with big image and engineering simulation with hardware accelerators.
26
McGinn, Richard. "Anti-ECP Effects in the Rejang Language of Sumatra." Canadian Journal of Linguistics/Revue canadienne de linguistique 43, no. 3-4 (December 1998): 359–76. http://dx.doi.org/10.1017/s000841310002452x.
Full textAbstract:
AbstractThis article explores some evidence against the ECP that appears at first to be fairly overwhelming. Upon deeper inspection, however, the evidence supports the ECP and a special universal computation involving the complementizer system, the Complementizer Contraction rule (Pesetsky 1982). Complementizer Contraction is parameterized; some languages have an overt reflex (French, Norwegian); other languages do not (English, Tagalog). To make the argument, many intricate details are described about the structure of relative clauses, comparative clauses, embedded complement clauses, and wh-questions in Rejang, a Western Austronesian language of Sumatra.
27
Blaschitz, Bernhard, Simon Breuss, Lukas Traxler, Laurin Ginner, and Svorad Ŝtolc. "High-speed Inline Computational Imaging for Area Scan Cameras." Electronic Imaging 2021, no. 6 (January 18, 2021): 301–1. http://dx.doi.org/10.2352/issn.2470-1173.2021.6.iriacv-301.
Full textAbstract:
For quality inspection in different industries, where objects may be transported at several m=s, acquisition and computation speed for 2d and 3d imaging even at resolutions in the micrometer (mm) scale is essential. AIT's well-established Inline Computational Imaging (ICI) system has until now used standard multilinescan cameras to build a linear light field stack. Unfortunately, this image readout mode is only supported by few camera manufacturers thus effectively limiting the application of ICI software. However, industrial grade area scan cameras now offer frame rates of several hundred FPS, so a novel method has been developed that can match previous speed requirements while upholding and eventually surpassing previous 3D reconstruction results even for challenging objects. AIT's new area scan ICI can be used with most standard industrial cameras and many different light sources. Nevertheless, AIT has also developed its own light source to illuminate a scene by high-frequency strobing tailored to this application. The new algorithms employ several consistency checks for a range of base lines and feature channels and give robust confidence values that ultimately improve subsequent 3D reconstruction results. Its lean output is well-suited for realtime applications while holding information from four different illumination direction. Qualitative comparisons with our previous method in terms of 3d reconstruction, speed and confidence are shown at a typical sampling of 22mm=pixel. In the future, this fast and robust inline inspection scheme will be extended to microscopic resolutions and to several orthogonal axes of transport.
28
Tang, Hong Yuan. "Reason Analysis and Treatment Measures of Cracks in a Masonry Structure." Applied Mechanics and Materials 71-78 (July 2011): 4610–13. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.4610.
Full textAbstract:
This paper analyses some kinds of fissures in walls of a multi-story masonry buildings with additional floor transformation, and puts up several methods for dealing with the fissures. Through the spot inspection and computation analysis, the reason of crack producing is put forward. Because the ring beams only built in the first and the top floor, and precast floor slabs used in the building, the overall structure rigidity is poor. The internal longitudinal wall is strengthened by steel tension bar, simultaneously; an addition shallow submersion foundation is added on the original foundation. After the reinforcement processing, the structure is complete until now.
29
Inkoom, Sylvester, John O. Sobanjo, Paul D. Thompson, Richard Kerr, and Richard Twumasi-Boakye. "Bridge Health Index: Study of Element Condition States and Importance Weights." Transportation Research Record: Journal of the Transportation Research Board 2612, no. 1 (January 2017): 67–75. http://dx.doi.org/10.3141/2612-08.
Full textAbstract:
The AASHTO Pontis bridge management system has been used to support network-level and project-level decision making on the condition and functional obsolescence of bridges. State departments of transportation often develop bridge inspection data collection methods, deterioration models, cost models, and other preservation analysis capabilities to comply with the requirements of the federal Government Accounting Standards Board. The bridge health index (BHI) in the Pontis bridge management system has been used in the evaluation of the condition of bridges and elements at the project and network levels. This paper investigates three issues in the computation of the BHI: the effects of using linear and nonlinear scales for the condition state weights when computing the element health index (EHI); the application of amplification weights to EHI values to emphasize bridge elements in bad condition; and the development of element weights based on element replacement costs, element long-term costs, element vulnerability to hazard risks, and a combination of these measures. Historical condition data from element-based inspection were used to evaluate these effects at the network level.
30
Wang, Hui, Zheng Zhang, Zhao Xiong, Tianye Liu, Kai Long, Xusong Quan, and Xiaodong Yuan. "An intelligent computation system for precise assembly of large laser optics." Assembly Automation 38, no. 4 (September 3, 2018): 524–35. http://dx.doi.org/10.1108/aa-04-2017-048.
Full textAbstract:
Purpose It is a huge technical and engineering challenge to realize the precise assembly of thousands of large optics in high power solid-state laser system. Using the 400-mm aperture-sized transport mirror as a case, this paper aims to present an intelligent numerical computation methodology for mounting performance analysis and modeling of large optics in a high-power laser system for inertial confinement fusion (ICF). Design/methodology/approach Fundamental principles of modeling and analysis of the transport mirror surface distortion are proposed, and a genetic algorithm-based computation framework is proposed to evaluate and optimize the assembly and mounting performance of large laser optics. Findings The stringent specifications of large ICF optics place very tight constraints upon the transport mirror’s assembly and mounts. The operational requirements on surface distortion [peak-to-valley and root mean square (RMS)] can be met as it is appropriately assembled by the close loop of assembly-inspection-optimization-fastening. In the end, the experimental study validates the reliability and effectiveness of the transport mirror mounting method. Originality/value In the assembly design and mounting performance evaluation of large laser optics, the whole study has the advantages of accurate evaluation and intelligent optimization on nano-level optical surface distortion, which provides a fundamental methodology for precise assembly and mounting of large ICF optics.
31
Omar, Mohammed A., Yi Zhou, Rohit Parvataneni, and Eric Planting. "Calibrated Pulse-Thermography Procedure for Inspecting HDPE." Research Letters in Materials Science 2008 (2008): 1–4. http://dx.doi.org/10.1155/2008/186427.
Full textAbstract:
This manuscript discusses the application of a pulse-thermography modality to evaluate the integrity of a high-density polyethylene HDPE joint for delamination, in nonintrusive manner. The inspected HDPE structure is a twin-cup shape, molded through extrusion, and the inspection system comprises a high-intensity, short-duration radiation pulse to excite thermal emission; the text calibrates the experiment settings (pulse duration, and detector sampling rate) to accommodate HDPE bulks thermal response. The acquired thermal scans are processed through new contrast computation named “self-referencing”, to investigate the joint tensile strength and further map its adhesion interface in real-time. The proposed system (hardware, software combination) performance is assessed through an ultrasound C-scan validation and further benchmarked using a standard pulse phase thermography (PPT) routine.
32
Pellegrino, S., and C. R. Calladine. "Structural Computation of an Assembly of Rigid Links, Frictionless Joints, and Elastic Springs." Journal of Applied Mechanics 58, no. 3 (September 1, 1991): 749–53. http://dx.doi.org/10.1115/1.2897259.
Full textAbstract:
The aim of the paper is to set up a scheme for efficient computation of the small-displacement response of a plane assembly of rigid links, frictionless joints, and elastic springs to static external forces applied at the joints. The particular assembly of Fig. 1 is used as an example. The conventional “stiffness method”-which becomes singular when, as here, the links are rigid-is abandoned in favor of a method which describes the current state of the assembly in terms of the amplitudes of m (here = 3) independent infinitesimal modes of inextensional deformation of the assembly; and the calculation boils down to the solving of an m x m (here 3 x 3) set of algebraic equations. The method is particularly straightforward if the inextensional modes (as here) may be obtained by inspection; but a general algorithm is presented for obtaining the inextensional modes of an arbitrary assembly of the same general kind. A major advantage over the conventional stiffness method-which requires, of course, the replacement of rigid links by (stiff) elastic members is that the number of variables may be reduced substantially. This can be very important for large assemblies.
33
Raeva, P., and K. Pavelka Jr. "OPTIMIZED POST-PROCESSING OF MULTIPLE UAV IMAGES FOR FORESTRY INSPECTIONS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2020 (August 6, 2020): 15–19. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2020-15-2020.
Full textAbstract:
Abstract. The following paper discusses possible optimized post-processing and data tracking of UAV imagery for forestry inspection. The survey took place in the National Natural Reserve Božídarské rašeliniště – The Wetland of Božídar from 2015 till now. The purpose of this study is to provide with a suitable post-processing method of UAV images in a protected area with no necessity of human interaction with the species. The authors used UAV imagery from RGB and multispectral sensors. The focus of the paper is the post-processing which relies solely on open-source tools. The results of the paper are a script for automatic computation of vegetation indices, a script for canopy height model in a certain part of the mapped area a possible GIS solution for storing and tracking the data.
34
Mariani, Stefano, and Francesco Lanza di Scalea. "Predictions of defect detection performance of air-coupled ultrasonic rail inspection system." Structural Health Monitoring 17, no. 3 (June 30, 2017): 684–705. http://dx.doi.org/10.1177/1475921717715429.
Full textAbstract:
A rail inspection system based on ultrasonic guided waves and non-contact (air-coupled) ultrasound transduction is under development at the University of California at San Diego. The system targets defects in the rail head that are major causes of train accidents. Because of the high acoustic impedance mismatch between air and steel, the non-contact system poses severe challenges and questions on the defect detection performance. This article presents an extensive numerical study, conducted with a local interaction simulation approach, to model the ultrasound propagation and interaction with defects in the proposed system. This model was used to predict the expected detection performance of the system in the presence of various defects of different sizes and positions, and at varying levels of signal-to-noise ratios. When possible, operating variables for the model were chosen consistently with the field test of an experimental prototype that was conducted in 2014. The defect detection performance was evaluated through the computation of receiver operating characteristic curves in terms of probability of detection versus probability of false alarms. The study indicates that despite the challenges of non-contact probing of the rail, quite satisfactory inspection performance can be expected for a variety of defect types, sizes, and positions. Beyond the specific cases examined in this article, this numerical framework can also be used in the future to examine a larger variety of field test conditions.
35
Hagiwara, Hayato, Yasufumi Touma, Kenichi Asami, and Mochimitsu Komori. "FPGA-Based Stereo Vision System Using Gradient Feature Correspondence." Journal of Robotics and Mechatronics 27, no. 6 (December 18, 2015): 681–90. http://dx.doi.org/10.20965/jrm.2015.p0681.
Full textAbstract:
<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270006/10.jpg"" width=""300"" /> Mobile robot with a stereo vision</div>This paper describes an autonomous mobile robot stereo vision system that uses gradient feature correspondence and local image feature computation on a field programmable gate array (FPGA). Among several studies on interest point detectors and descriptors for having a mobile robot navigate are the Harris operator and scale-invariant feature transform (SIFT). Most of these require heavy computation, however, and using them may burden some computers. Our purpose here is to present an interest point detector and a descriptor suitable for FPGA implementation. Results show that a detector using gradient variance inspection performs faster than SIFT or speeded-up robust features (SURF), and is more robust against illumination changes than any other method compared in this study. A descriptor with a hierarchical gradient structure has a simpler algorithm than SIFT and SURF descriptors, and the result of stereo matching achieves better performance than SIFT or SURF.
36
Xu, Ke, Peng Zhou, and Chao Lin Yang. "Application of Fractal Dimension Feature to Recognition of Surface Defects on Hot-Rolled Strips." Applied Mechanics and Materials 152-154 (January 2012): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.526.
Full textAbstract:
Because steel strips are covered with scales and water during hot-rolling, it is difficult to recognize the defects from images of hot-rolled strips through conventional methods. Principles and characteristics of fractal dimensions were studied, and computation of the fractal dimensions of the defect images with Peleg Covered Carpet is presented. Fractal dimensions of piecewise linearly transformed and smoothed images were used as features for classification of defects. These features were inputted to train the AdaBoost classifier. Experiments with samples of pimples, shells and scales from a real surface inspection system of hot-rolled strips showed that it is effective to recognized scales from other defects, and the total classification rate of this method is higher than 90%.
37
Hadavandsiri, Zahra, Derek D. Lichti, Adam Jahraus, and David Jarron. "Concrete Preliminary Damage Inspection by Classification of Terrestrial Laser Scanner Point Clouds through Systematic Threshold Definition." ISPRS International Journal of Geo-Information 8, no. 12 (December 13, 2019): 585. http://dx.doi.org/10.3390/ijgi8120585.
Full textAbstract:
This paper presents a novel approach for automatic, preliminary detection of damage in concrete structures using ground-based terrestrial laser scanners. The method is based on computation of defect-sensitive features such as the surface curvature, since the surface roughness changes strongly if an area is affected by damage. A robust version of principal component analysis (PCA) classification is proposed to distinguish between structural damage and outliers present in the laser scanning data. Numerical simulations were conducted to develop a systematic point-wise defect classifier that automatically diagnoses the location of superficial damage on the investigated region. The method provides a complete picture of the surface health of concrete structures. It has been tested on two real datasets: a concrete heritage aqueduct in Brooks, Alberta, Canada; and a civil pedestrian concrete structure. The experiment results demonstrate the validity and accuracy of the proposed systematic framework for detecting and localizing areas of damage as small as 1 cm or less.
38
Yang, M. D., and T. C. Su. "Automation model of sewerage rehabilitation planning." Water Science and Technology 54, no. 11-12 (December 1, 2006): 225–32. http://dx.doi.org/10.2166/wst.2006.805.
Full textAbstract:
The major steps of sewerage rehabilitation include inspection of sewerage, assessment of structural conditions, computation of structural condition grades, and determination of rehabilitation methods and materials. Conventionally, sewerage rehabilitation planning relies on experts with professional background that is tedious and time-consuming. This paper proposes an automation model of planning optimal sewerage rehabilitation strategies for the sewer system by integrating image process, clustering technology, optimization, and visualization display. Firstly, image processing techniques, such as wavelet transformation and co-occurrence features extraction, were employed to extract various characteristics of structural failures from CCTV inspection images. Secondly, a classification neural network was established to automatically interpret the structural conditions by comparing the extracted features with the typical failures in a databank. Then, to achieve optimal rehabilitation efficiency, a genetic algorithm was used to determine appropriate rehabilitation methods and substitution materials for the pipe sections with a risk of mal-function and even collapse. Finally, the result from the automation model can be visualized in a geographic information system in which essential information of the sewer system and sewerage rehabilitation plans are graphically displayed. For demonstration, the automation model of optimal sewerage rehabilitation planning was applied to a sewer system in east Taichung, Chinese Taiwan.
39
Liu, Fu Ping, An Ling Wang, and Ming Chang Zhang. "Effect of Fluid inside Casing on Resistivity Logging Response through Casing." Advanced Materials Research 361-363 (October 2011): 70–75. http://dx.doi.org/10.4028/www.scientific.net/amr.361-363.70.
Full textAbstract:
With the help of the transmission line measure method of formation resistivity through casing, we have presented a calculated approach of potential distribution on the metal casing and in the fluid inside casing, realized the calculation of the resistivity logging response(RLR)of formation, and made inspection for two measure methods of formation resistivity. The numerical computing results show that the fluid in casing hardly has influence on the RLR of formation, but, when there are different kinds of fluids in casing, the interface of fluids has an obvious logging response for RLTA, and the response range of fluid interface is about the length of tool electrode spacing. The calculating examples also show that the measure and computation methods of formation resistivity for logging response have a larger effect when inside casing with fluid.
40
Chlewicki, Wojciech, Katarzyna Cichoń, Magda Zolubak, Stepan Ozana, and Aleksandra Kawala-Sterniuk. "XShields: Cross-platform Application for the Design of Shields against Ionizing Radiation." Studies in Logic, Grammar and Rhetoric 60, no. 1 (December 1, 2019): 75–84. http://dx.doi.org/10.2478/slgr-2019-0046.
Full textAbstract:
Abstract In many cases medical diagnosis is based on information obtained through a process involving the emission of different forms of ionizing radiation. The safety of the medical staff and patients exposed to ionizing radiation is highly dependent on the proper design of the shielding used in the laboratory. Therefore, the authors propose a multi-platform application supporting such a design through the computation of the critical parameters of shielding. The specific requirements for shielding are defined by government authorities so the algorithm must comply with all the written standards. The application was implemented using Xamarin. Forms for cross-platform development. The results obtained with the use of the developed tool were compared with those calculated manually for the design of stationary shields developed, deployed, and validated by local inspection.
41
Pandit, S. M., N. Jordache, and G. A. Joshi. "Computer Rigid Disk Surface Assessment With Laser Interferometry Using DDS." Journal of Manufacturing Science and Engineering 118, no. 3 (August 1, 1996): 448–55. http://dx.doi.org/10.1115/1.2831053.
Full textAbstract:
Laser interferometry in conjunction with the data dependent systems (DDS) methodology is first used in this paper to eliminate errors caused by instrumentation and software, and to recover the surface topography of a computer rigid disk used for illustration. The DDS methodology is then applied once more to decompose the surface height profile into a series of exponential and sinusoidal modes. The significant modes are related to the waviness and surface roughness resulting from different manufacturing processes. Surface reconstruction using only the important modes is presented. This provides a visual as well as mathematical description of the resultant effect of each process. The methodology can characterize very complex surface textures, reducing the reliance on complicated and expensive instruments needed for inspection, and replacing them with relatively inexpensive but reliable computation.
42
Marteau, Julie, Raphaël Deltombe, and Maxence Bigerelle. "Quantification of the Morphological Signature of Roping Based on Multiscale Analysis and Autocorrelation Function Description." Materials 13, no. 13 (July 7, 2020): 3040. http://dx.doi.org/10.3390/ma13133040.
Full textAbstract:
Roping or ridging is a visual defect affecting the surface of ferritic stainless steels, assessed using visual inspection of the surfaces. The aim of this study was to quantify the morphological signature of roping to link roughness results with five levels of roping identified with visual inspection. First, the multiscale analysis of roughness showed that the texture aspect ratio Str computed with a low-pass filter of 32 µm gave a clear separation between the acceptable levels of roping and the non-acceptable levels (rejected sheets). To obtain a gradation description of roping instead of a binary description, a methodology based on the use of the autocorrelation function was created. It consisted of several steps: a low-pass filtering of the autocorrelation function at 150 µm, the segmentation of the autocorrelation into four stabilized portions, and finally, the computation of isotropy and the root-mean-square roughness Sq on the obtained quarters of function. The use of the isotropy combined with the root-mean-square roughness Sq led to a clear separation of the five levels of roping: the acceptable levels of roping corresponded to strong isotropy (values larger than 10%) coupled with low root-mean-square roughness Sq. Both methodologies can be used to quantitatively describe surface morphology of roping in order to improve our understanding of the roping phenomenon.
43
Akça, Irfan, and Ahmet Tuğrul Basokur. "Extraction of structure-based geoelectric models by hybrid genetic algorithms." GEOPHYSICS 75, no. 1 (January 2010): F15—F22. http://dx.doi.org/10.1190/1.3273851.
Full textAbstract:
A major difficulty in electrical resistivity imaging is the identification of the lithologic units, especially in the sedimentary environments. The geologic interpretation generally is realized by visual inspection of the final resistivity section. Although sharp boundary inversion techniques based on a local linearization could allow the delineation of interfaces between geologic units, these techniques will succeed only if an initial model already close to the best solution is available. Stochastic algorithms might localize a point around the global minimum of the misfit function; however, they are not efficient at finding the precise solution. For this reason, our previously published hybrid genetic algorithms, derived from evolution theories, are used to verify structure-based models. The geometric parameters are defined by thickness values of the lithologic units at control points distributed along the horizontal axis. A zero thickness value indicates the nonexistence of a certain unit at the corresponding con-trol point. An unstructured grid composed of irregular triangles is constructed by the application of Delaunay triangulations to represent complicated structural boundaries. In addition, the computation time for the calculation of model response is reduced greatly by this strategy. Because the suggested parameterization reduces the number of unknown parameters to a few tens and the computation time for the model responses is reduced by the Delaunay triangulation, the implementation of hybrid genetic algorithms for 2D problems becomes possible. A huge number of models are generated randomly in the first generation (a population of parameters) and then updated in subsequent generations by the simulation of biological processes. The suggested algorithms consist of two computational phases. In the first stage, the physical property of each subsurface layer is represented by a distinct resistivity value. After some succeeding genera-tions, laterally varying resistivities within the same lithologic unit are permitted to simulate lateral changes in geologic conditions.
44
Moltchanova, Elena, Shirin Sharifiamina, Derrick J. Moot, Ali Shayanfar, and Mark Bloomberg. "Comparison of three different statistical approaches (non-linear least-squares regression, survival analysis and Bayesian inference) in their usefulness for estimating hydrothermal time models of seed germination." Seed Science Research 30, no. 1 (March 2020): 64–72. http://dx.doi.org/10.1017/s0960258520000082.
Full textAbstract:
AbstractHydrothermal time (HTT) models describe the time course of seed germination for a population of seeds under specific temperature and water potential conditions. The parameters of the HTT model are usually estimated using either a linear regression, non-linear least squares estimation or a generalized linear regression model. There are problems with these approaches, including loss of information, and censoring and lack of independence in the germination data. Model estimation may require optimization, and this can have a heavy computational burden. Here, we compare non-linear regression with survival and Bayesian methods, to estimate HTT models for germination of two clover species. All three methods estimated similar HTT model parameters with similar root mean squared errors. However, the Bayesian approach allowed (1) efficient estimation of model parameters without the need for computation-intensive methods and (2) easy comparison of HTT parameters for the two clover species. HTT models that accounted for a species effect were superior to those that did not. Inspection of credibility intervals and estimated posterior distributions for the Bayesian HTT model shows that it is credible that most HTT model parameters were different for the two clover species, and these differences were consistent with known biological differences between species in their germination behaviour.
45
Chu, Wen-Lin, Chih-Jer Lin, and Kai-Chun Kao. "Fault Diagnosis of a Rotor and Ball-Bearing System Using DWT Integrated with SVM, GRNN, and Visual Dot Patterns." Sensors 19, no. 21 (November 5, 2019): 4806. http://dx.doi.org/10.3390/s19214806.
Full textAbstract:
In this study, a set of methods for the inspection of a working motor in real time was proposed. The aim was to determine if ball-bearing operation is normal or abnormal and to conduct an inspection in real time. The system consists of motor control and measurement systems. The motor control system provides a set fixed speed, and the measurement system uses an accelerometer to measure the vibration, and the collected signal data are sent to a PC for analysis. This paper gives the details of the decomposition of vibration signals, using discrete wavelet transform (DWT) and computation of the features. It includes the classification of the features after analysis. Two major methods are used for the diagnosis of malfunction, the support vector machines (SVM) and general regression neural networks (GRNN). For visualization and to input the signals for visualization, they were input into a convolutional neural network (CNN) for further classification, as well as for the comparison of performance and results. Unique experimental processes were established with a particular hardware combination, and a comparison with commonly used methods was made. The results can be used for the design of a real-time motor that bears a diagnostic and malfunction warning system. This research establishes its own experimental process, according to the hardware combination and comparison of commonly used methods in research; a design for a real-time diagnosis of motor malfunction, as well as an early warning system, can be built thereupon.
46
Khosiawan, Yohanes, Sebastian Scherer, and Izabela Nielsen. "Toward delay-tolerant multiple-unmanned aerial vehicle scheduling system using Multi-strategy Coevolution algorithm." Advances in Mechanical Engineering 10, no. 12 (December 2018): 168781401881523. http://dx.doi.org/10.1177/1687814018815235.
Full textAbstract:
Autonomous bridge inspection operations using unmanned aerial vehicles take multiple task assignments and constraints into account. To efficiently execute the operations, a schedule is required. Generating a cost optimum schedule of multiple-unmanned aerial vehicle operations is known to be Non-deterministic Polynomial-time (NP)-hard. This study approaches such a problem with heuristic-based algorithms to get a high-quality feasible solution in a short computation time. A constructive heuristic called Retractable Chain Task Assignment algorithm is presented to build an evaluable schedule from a task sequence. The task sequence representation is used during the search to perform seamless operations. Retractable Chain Task Assignment algorithm calculates and incorporates slack time to the schedule according to the properties of the task. The slack time acts as a cushion which makes the schedule delay-tolerant. This algorithm is incorporated with a metaheuristic algorithm called Multi-strategy Coevolution to search the solution space. The proposed algorithm is verified through numerical simulations, which take inputs from real flight test data. The obtained solutions are evaluated based on the makespan, battery consumption, computation time, and the robustness level of the schedules. The performance of Multi-strategy Coevolution is compared to Differential Evolution, Particle Swarm Optimization, and Differential Evolution–Fused Particle Swarm Optimization. The simulation results show that Multi-strategy Coevolution gives better objective values than the other algorithms.
47
Ahmadi, Atefeh, Xiong Wang, Fahimeh Nazarimehr, Fawaz E. Alsaadi, Fuad E. Alsaadi, and Viet-Thanh Pham. "Coexisting infinitely many attractors in a new chaotic system with a curve of equilibria: Its extreme multi-stability and Kolmogorov–Sinai entropy computation." Advances in Mechanical Engineering 11, no. 11 (November 2019): 168781401988804. http://dx.doi.org/10.1177/1687814019888046.
Full textAbstract:
A new five-dimensional chaotic system with extreme multi-stability is introduced in this article. The mathematical model is established, and numerical simulations are done. This dynamical system complicates incident of extreme multi-stability. Most significantly, relied on the mathematical model, the recently proposed system has a curve of equilibria that ends in the occurrence of hidden attractors. We examine the initial-condition-dependent dynamics of this system. We inspect that there is an unrestricted number of coexistent attractors, which signifies the occurrence of extreme multi-stability strictly. In addition, the extreme multi-stability according to initial condition is investigated consuming the Lyapunov exponent spectra and bifurcation diagrams. The existence of coexisting infinitely many attractors is displayed with phase portraits. In the end, we calculate and debate Kolmogorov–Sinai entropy in the chaotic system. We direct trying the Kolmogorov–Sinai technique of entropic inspection for the dynamics of the system.
48
Meo, A., L. Profumo, A. Rossi, and M. Lanzetta. "Optimum Dataset Size and Search Space for Minimum Zone Roundness Evaluation by Genetic Algorithm." Measurement Science Review 13, no. 3 (June 1, 2013): 100–107. http://dx.doi.org/10.2478/msr-2013-0018.
Full textAbstract:
Roundness is one of the most common features in machining. The minimum zone tolerance (MZT) approach provides the minimum roundness error, i.e. the minimum distance between the two concentric reference circles containing the acquired profile; more accurate form error estimation results in less false part rejections. MZT is still an open problem and is approached here by a Genetic Algorithm. Only few authors have addressed the definition of the search space center and size and its relationship with the dataset size, which greatly influence the inspection time for the profile measurement and the convergence speed of the roundness estimation algorithm for a given target accuracy. Experimental tests on certified roundness profiles, using the profile centroid as the search space center, have shown that the search space size is related to the number of dataset points and an optimum exists, which provides a computation time reduction up to an order of magnitude.
49
Mormann, F., M. Bausch, S. Knieling, and I. Fried. "Neurons in the Human Left Amygdala Automatically Encode Subjective Value Irrespective of Task." Cerebral Cortex 29, no. 1 (December 1, 2017): 265–72. http://dx.doi.org/10.1093/cercor/bhx330.
Full textAbstract:
Abstract The amygdala plays an important role in the computation of internal reward signals. In animals it has been shown to enable a stimulus to indicate the current value of a reinforcer. However, the exact nature of the current value representations in humans remains unknown. Specifically, do neurons of the human amygdala represent current value signals only in tasks requiring valuation? We recorded from 406 neurons in the amygdala, orbitofrontal cortex, parahippocampal cortex, entorhinal cortex, and hippocampus of 6 neurosurgical patients while subjects repeatedly viewed 40 different pictures of sweet or salty “junk food” items in 2 different tasks. Neural activity during stimulus inspection in a valuation task reflected food preferences in the amygdala, orbitofrontal cortex, hippocampus, and entorhinal cortex. Notably, only left amygdala activity represented these food preferences even in a sweet–salty classification task. Valuation signals of the left amygdala thus appear to be stimulus-, not-task driven.
50
Chebbi, Houssem, and Denis Prémel. "The fast computation of eddy current distribution and probe response in homogenized composite material based on semi-analytical approach." European Physical Journal Applied Physics 89, no. 1 (January 2020): 10901. http://dx.doi.org/10.1051/epjap/2020190220.
Full textAbstract:
Due to the excessive use of composites in the industrial field, many numerical modeling approaches dedicated to the characterization of such complex material by means of Non Destructive Testing Techniques were developed. In this paper, we present a numerical model dedicated to simulate the inspection of unidirectional Carbon Fiber Reinforced Polymer using Eddy Current technique for detecting fiber disorientation. A semi-analytical model based on a modal approach is developed for the fast computation of quasi-static field induced by an arbitrary 3D Eddy Current probe in the material. Because of the high anisotropy and strong heterogeneity of such material, a prior phase of homogenization is assumed and the material is then considered as homogeneously anisotropic. The modal approach consists in resolving Maxwell’s equations in the Fourier domain. Therefore, the electromagnetic field is expressed as a sum of eigen-modes. To take into account the wave propagation through the multilayered structure and boundary conditions at each separating interface, a stable and recursive scattering matrix algorithm has been implemented. The impedance of the probe is computed analytically using Auld’s formula in orders to identify the main orientation of the fibers in the inspected zone. For numerical validation, simulated data provided by the model are compared to finite element data.