Relevant bibliographies by topics / Fuzzy boundary layer

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Fuzzy boundary layer'

Author: Grafiati
Published: 3 June 2025
Last updated: 23 June 2025

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Journal articles on the topic "Fuzzy boundary layer"

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Smith, Elizabeth N., and Jacob T. Carlin. "A multi-instrument fuzzy logic boundary-layer-top detection algorithm." Atmospheric Measurement Techniques 17, no. 13 (2024): 4087–107. http://dx.doi.org/10.5194/amt-17-4087-2024.

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Abstract. Understanding the boundary-layer height and its dynamics is crucial for a wide array of applications spanning various fields. Accurate identification of the boundary-layer top contributes to improved air quality predictions, pollutant transport assessments, and enhanced numerical weather prediction through parameterization and assimilation techniques. Despite its significance, defining and observing the boundary-layer top remain challenging. Existing methods of estimating the boundary-layer height encompass radiosonde-based methods, radar-based retrievals, and more. As emerging boundary-layer observation platforms emerge, it is useful to reevaluate the efficacy of existing boundary-layer-top detection methods and explore new ones. This study introduces a fuzzy logic algorithm that leverages the synergy of multiple remote sensing boundary-layer profiling instruments: a Doppler lidar, infrared spectrometer, and microwave radiometer. By harnessing the distinct advantages of each sensing platform, the proposed method enables accurate boundary-layer height estimation both during daytime and nocturnal conditions. The algorithm is benchmarked against radiosonde-derived boundary-layer-top estimates obtained from balloon launches across diverse locations in Wisconsin, Oklahoma, and Louisiana during summer and fall. The findings reveal notable similarities between the results produced by the proposed fuzzy logic algorithm and traditional radiosonde-based approaches. However, this study delves into the nuanced differences in their behavior, providing insightful analyses about the underlying causes of the observed discrepancies. While developed with the three instruments mentioned above, the fuzzy logic boundary-layer-top detection algorithm, called BLISS-FL, could be adapted for other wind and thermodynamic profilers. BLISS-FL is released publicly, fostering collaboration and advancement within the research community.
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Lee, Heejin, Dong-Yon Kim, Taeck-Kie Lee, Sang-Hoon Kim, and Mignon Park. "Tracking Control of Variable Structure Using Fuzzy Variable Boundary Layer." Journal of Advanced Computational Intelligence and Intelligent Informatics 3, no. 4 (1999): 332–38. http://dx.doi.org/10.20965/jaciii.1999.p0332.

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Control gain greatly affects variable structure system (VSS) performance as a system design parameter. The thin boundary layer used to eliminate chatter neighbors the sliding surface. Sliding control based on a variable boundary layer tracks better than a fixed layer. We propose variable structure control using fuzzy algorithms in control gain and the boundary layer to increase tracking efficiency, proving its feasibility in application to a simple nonlinear system.
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Bianco, Laura, James M. Wilczak, and Allen B. White. "Convective Boundary Layer Depth Estimation from Wind Profilers: Statistical Comparison between an Automated Algorithm and Expert Estimations." Journal of Atmospheric and Oceanic Technology 25, no. 8 (2008): 1397–413. http://dx.doi.org/10.1175/2008jtecha981.1.

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Abstract A previous study showed success in determining the convective boundary layer depth with radar wind-profiling radars using fuzzy logic methods, and improvements to the earlier work are discussed. The improved method uses the Vaisala multipeak picking (MPP) procedure to identify the atmospheric signal in radar spectra in place of a fuzzy logic peak picking procedure that was previously used. The method then applies fuzzy logic techniques to calculate the depth of the convective boundary layer. The planetary boundary layer depth algorithm is improved with respect to the one used in the previous study in that it adds information obtained from the small-scale turbulence (vertical profiles of the spectral width of the vertical velocity), while also still using vertical profiles of the radar-derived refractive index structure parameter C2n and the variance of vertical velocity. Modifications to the fuzzy logic rules (especially to those using vertical velocity data) that improve the algorithm’s accuracy in cloudy boundary layers are incorporated. In addition, a reliability threshold value to the fuzzy logic–derived score is applied to eliminate PBL depth data values with low score values. These low score values correspond to periods when the PBL structure does not match the conceptual model of the convective PBL built into the algorithm. Also, as a final step, an optional temporal continuity test on boundary layer depth has been developed that helps improve the algorithm’s skill. A comparison with independent boundary layer depth estimations made “by eye” by meteorologists at two radar wind-profiler sites, significantly different in their characteristics, shows that the new improved method gives significantly more accurate estimates of the boundary layer depth than does the previous method, and also much better estimates than the simpler “standard” method of selecting the peak of C2n. The new method produces an absolute error of the mixing-depth estimates comparable to the vertical range resolution of the profilers.
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Lu, Hua Cai, Juan Ti, Yi Ming Yuan, and Li Sheng Wei. "Sensorless Control for PMLSM Based on Fuzzy Sliding Mode Observer." Applied Mechanics and Materials 556-562 (May 2014): 2270–73. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.2270.

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In this paper, a new sensorless control method is proposed for a permanent magnet linear synchronous motor based on Fuzzy sliding mode observer, which combines the advantages of sliding mode observer and Fuzzy controller respectively. The difference between the current estimated value and the actual current value is regarded as sliding mode function; sliding mode function (current error) and variation of the error are used as the input of fuzzy controller, and the width of the boundary layer as the output, adjusting the width of the boundary layer dynamically in real time. The simulation results show that Fuzzy sliding mode observer is able to find a balance between soft chattering and steady-state error, keep the system robustness and control precision.
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Zhang, Xiaoyu. "Sliding Mode-Like Fuzzy Logic Control With Adaptive Boundary Layer for Multiple-Variable Discrete Nonlinear Systems." Journal of Intelligent Systems 25, no. 2 (2016): 209–20. http://dx.doi.org/10.1515/jisys-2015-0019.

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AbstractMore serious chattering emerges in discrete systems of sliding mode control. The paper presents a sliding mode-like fuzzy logic control design, which eliminates the chattering, for a class of discrete nonlinear systems with multiple variables. First, the boundary layer is self-tuned on-line, and then, the chattering free is obtained. Consequently, the fuzzy logic control (FLC) is designed to approximate the sliding mode control (SMC) with boundary layer self-tuning. Finally, the performance of the robustness, chattering free, and adaption are verified by the simulation results.
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Yang, Jie, Tian Luo, Fan Zhao, Shuai Li, and Wei Zhou. "Fuzzy Knowledge Distance with Three-Layer Perspectives in Neighborhood System." Mathematical Problems in Engineering 2021 (May 22, 2021): 1–15. http://dx.doi.org/10.1155/2021/9977488.

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Information granule is the basic element in granular computing (GrC), and it can be obtained according to the granulation criterion. In neighborhood rough sets, current uncertainty measures focus on computing the knowledge granulation of single granular space and have two main limitations: (i) neglecting the structural information of boundary regions and (ii) the inability to reflect the difference between neighborhood granular spaces with the same uncertainty for approximating a target concept. Firstly, a fuzziness-based uncertainty measure for neighborhood rough sets is introduced to characterize the structural information of boundary regions. Moreover, from the perspective of distance, based on the idea of density peaks, we present a fuzzy-neighborhood-granule-distance- (FNGD-) based method to discover the relationship between granules in a granular space. Then, to characterize the difference between granular spaces for approximating a target concept, we present the fuzzy neighborhood granular space distance (FNGSD) and fuzzy neighborhood boundary region distance (FNBRD). FNGD, FNGSD, and FNBRD are hierarchically organized from fineness to coarseness according to the semantics of granularity, which provide three-layer perspectives in the neighborhood system.
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Lee, Heejin, Euntai Kim, Hyung-Jin Kang, and Mignon Park. "A new sliding-mode control with fuzzy boundary layer." Fuzzy Sets and Systems 120, no. 1 (2001): 135–43. http://dx.doi.org/10.1016/s0165-0114(99)00072-x.

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Tu, K. Y., T. T. Lee, and C. H. Wang. "Design of a New Fuzzy Suction Controller Using Fuzzy Modeling for Nonlinear Boundary Layer." IEEE Transactions on Fuzzy Systems 13, no. 5 (2005): 605–16. http://dx.doi.org/10.1109/tfuzz.2005.856564.

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Jiang, Shan, Wenhao Feng, Peng Zheng, Jun Liu, and Jun Yang. "Pneumatic position servo control of magnetic resonance compatible needle insertion robot." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, no. 7 (2012): 1469–80. http://dx.doi.org/10.1177/0954406212460972.

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This paper presents a control methodology that enables nonlinear model-base control of pulse width modulated (PWM) pneumatic position servo control system of a magnetic resonance (MR) compatible needle insertion robot used for MRI-guided prostate brachytherapy. Sliding mode control with a boundary layer is investigated based on the equivalent continuous-time dynamic model. Considering chattering in sliding mode control applications, especially in motion control of the robot, a fuzzy method is developed to tune the boundary layer of the sliding mode controller. Simulation and experimental results indicate that the controller is effective in both position control and trajectory tracking. With the boundary layer increasing, the steady state error of the response is becoming larger; however the maximum error is less than 0.2 mm. This steady state performance meets the accuracy requirement.
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J. Nirmala. "A New Inventive Approach to Nano Fuzzy Soft Topological Space Using Mathematical Analysis." Communications on Applied Nonlinear Analysis 31, no. 8s (2024): 747–56. http://dx.doi.org/10.52783/cana.v31.1586.

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The important theme of this paper is to define a lower and upper approximation for the set under consideration in order to examine a novel class of topological field known as Nano fuzzy soft topological space. Fuzzy topology coverts ordered structure to topological structure by using by its own criteria conditions. Nano topology is defined with the help of equivalence relation so that even micro spacing is included in the topological space. The condition of these two topological space has been merged and a new space known as Nano fuzzy topological space has been investigated and studied. Soft sets are an abstraction of fuzzy set theory which was interposed to deal with uncertainty conditions using parameters. Using soft sets, Nano fuzzy topology can be extended to a new form called Nano fuzzy soft topological space and it can be used to study matters of vagueness by defining a proper boundary layer. Since this concept depends upon defining appropriate boundary layers using topological concepts, it easy to determine the key components for a particular problem by properly defining three important regions which are upper approximation area, lower approximation area and boundary region. The use of Nano fuzzy soft topological space in predicting the cause of a disease has been discussed in this paper. It can be extended to study any complex problems in real life by converting it to a Nano fuzzy soft topological space using the three main key factors.
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Dissertations / Theses on the topic "Fuzzy boundary layer"

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Hasanaj, Edmir. "Experimental investigation of the boundary layer-based sliding mode control and single-input model-based sliding mode fuzzy logic control with applications to robot manipulators." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ54109.pdf.

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Štverka, Dalibor. "Analýza koaxiálních a jednovodičových nehomogenních struktur v časové oblasti." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233486.

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The work considers pulse wire-guided electromagnetic (EM) waves. The main contribution of the work is the original design of the isolation bushing for maximizing of the received wave (echo) thanks to the results of the numerical simulations, the acquirement of the new acknowledges of the reflections of the guided EM wave from the various boundaries, the construction of PML layers for FDTD simulations in rotational coordinates, the advances made in temporary excitation sources for FDTD and the formulation of the program code for FDTD in rotational coordinates in Matlab environment. The rightness of the numerical simulations was verified in practical experiments. The practical exploitation of the results is supposed in instrumentation and control technology - the level measurement in reservoirs.
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Books on the topic "Fuzzy boundary layer"

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Cox, Laurence. European Buddhist Traditions. Edited by Michael Jerryson. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199362387.013.14.

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This chapter covers those Buddhist traditions that are largely based in Europe, noting some of the specificities of this history as against the North American with which it is sometimes conflated. While the reception history of Buddhism in Europe stretches back to Alexander, Buddhist organization in Europe begins in the later nineteenth century, with the partial exception of indigenous Buddhisms in the Russian Empire. The chapter discusses Asian-oriented Buddhisms with a strong European base; European neo-traditionalisms founded by charismatic individuals; explicitly new beginnings; and the broader world of “fuzzy religion” with Buddhist components, including New Age, “nightstand Buddhists,” Christian creolizations, secular mindfulness, and Engaged Buddhism. In general terms, European Buddhist traditions reproduce the wider decline of religious institutionalization and boundary formation that shapes much of European religion generally.
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Book chapters on the topic "Fuzzy boundary layer"

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Meng, Fanzhao, Wang Han, and Lijun Yang. "Entrainment Mechanism Analysis of Oblique Shock-Wave/Boundary-Layer Interactions." In IUTAM Bookseries. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-78151-3_9.

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AbstractThe interaction between shock waves and boundary layers impacts hypersonic vehicles’ aerodynamic structure, internal turbulent mixing, and combustion processes. Direct numerical simulations (DNSs) of the hypersonic boundary layer have been performed to study the turbulent/non-turbulent interface (TNTI) entrainment mechanism and the impact of shock waves. Two cases are analyzed with and without the shock-wave and boundary layer interaction. A novel approach is proposed to identify TNTI by integrating the vorticity threshold and fuzzy clustering method. To account for the influence of increasing Reynolds number in the flow direction on the vorticity threshold analysis, vorticity is normalized using the local boundary layer thickness and friction velocity. Two entrainment mechanisms are quantitatively described and compared using TNTI local entrainment velocity and the mass conservation equation. The results demonstrate that the entrainment process within the hypersonic boundary layer TNTI is predominantly governed by large-scale engulfment, and under the influence of shock waves, the dominance of large-scale ingestion is notably enhanced.
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Ciaramella, Angelo, Angelo Riccio, Federico Angelini, Gian Paolo Gobbi, and Tony Christian Landi. "Statistical and Fuzzy Approaches for Atmospheric Boundary Layer Classification." In AI*IA 2009: Emergent Perspectives in Artificial Intelligence. Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-10291-2_38.

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Zhang, Xiaoyu, and Fang Guo. "Sliding Mode-Like Fuzzy Logic Control with Boundary Layer Self-Tuning for Discrete Nonlinear Systems." In Foundations and Applications of Intelligent Systems. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-37829-4_41.

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Wajeed, Mohammed Abdul. "Fuzzy Systems and Applications from an Engineer’s Perspective (Fuzzy Textual Data Classification - Case Study)." In Recent Developments in Artificial Intelligence and Communication Technologies. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9781681089676122010010.

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Soft computing has arisen as a standard presuming perspective; fuzzy ideashave advanced as imperative in the field of processing. The present chapter wouldexpect to motivate and support the reader by giving all the necessary flavorsempowering him to seek after and exude creative thoughts in the field of the fuzzyframework. The chapter presents the fundamental fuzzy ideas, including the operationsperformed on uncertainty sets. Fuzzy ideas and operations are contrasted with crispysets for the better cognizance of the pursuers, specifically the naive. How theprobabilistic and fuzzy frameworks (level of truthness) vary would be underscored withsufficient situations. Uncertainty, vagueness in the data, and historical crispy data whenutilized later, would connect some vulnerability with it; an embodiment of suchvulnerability and its need to consider in the processing is managed in detail. Differentfuzzy membership functions commonly used are explored here. The underlyingterminology (core, support and boundary) and its significance in the membershipfunctions are explored. In the last segment of the section, text categorization (TC)application utilizing the fuzzy ideas in processing is investigated. The features in TCare transformed into fuzzy collections (soft, hard and blended) as feature reduction.Gaussian function is employed in the process of obtaining the fuzzy collections.Itemized steps during the time spent treating word-based data classification are talkedabout.
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Benjamin, Roy. "By the Light of Philophosy." In Beating the Bounds. University Press of Florida, 2023. http://dx.doi.org/10.5744/florida/9780813069616.003.0008.

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This chapter examines analogues in the Wake to the attempts to establish boundaries in the early Wittgenstein as opposed to his later questioning of such boundaries. The Wake also undermines the clearly drawn boundaries of Aristotle’s law of the excluded middle with Bruno’s coincidence of contraries. In addition, the clearly drawn boundaries of Aristotle’s genus and species are blurred by the notion of fuzzy species. Darwin’s theory of evolution, Bergson’s philosophy of motion, change, and process, and Lovejoy’s notion of twilight zones and liminal spaces, all tended to break down these boundaries. The appearance in Ulysses and the Wake of liminal cases like bats, seals, and walruses illustrate this breakdown. Bart Kosco’s notion of fuzzy thinking which replaces the binary “either/or” with a shifting “more or less” also illuminates many passages in the Wake. Finally, the notion of vague areas and the sorites paradox which points out the difficulties of drawing a boundary between a heap and a non-heap further complicate the attempt to draw philosophical boundaries.
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Gans, Herbert J. "My Years in Antipoverty Research and Policy." In Our Studies Ourselves. Oxford University PressNew York, NY, 2003. http://dx.doi.org/10.1093/oso/9780195146615.003.0009.

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Abstract This chapter is a partial account of my forty years in antipoverty research and policy. The story begins with my coming to America as a refugee in 1940 and becoming concerned with inequality a few years later. However, I required another fifteen years, as well as a sudden invitation to conduct research in a relatively poor community, to be truly gripped by American poverty. My subconscious may tell another story, but except for coming here as a poor thirteen-year-old, my research, writing, and other antipoverty activities have not been shaped significantly by my personal life. My work in this area has not really changed my personal life either, but in the academy, the boundary between work and personal life is fuzzy and porous to begin with. In any case, both my life and my work have been pushed and pulled to a great extent by events and by the larger agencies and forces that generated them. I was born in Cologne, Germany, and grew up in a comfortably middleclass, German-Jewish family, but in 1939 we left Nazi Germany with little more than our clothes.
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Conference papers on the topic "Fuzzy boundary layer"

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Wu, Xu, Kenan Wu, and Wenting Jiang. "Fuzzy control iterative algorithm for beam uniformity enhancement of gas laser through boundary layer flow." In International Symposium on Photonics and Optoelectronics (SOPO 2014), edited by Zhiping Zhou. SPIE, 2014. http://dx.doi.org/10.1117/12.2068204.

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Wang, Fei, and Cheng Guan. "Variable gain sliding mode control with fuzzy boundary layer for hydraulic excavating robot." In 2013 International Conference of Information Technology and Industrial Engineering. WIT Press, 2013. http://dx.doi.org/10.2495/itie131672.

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Abdelgalil, Y. A., and N. G. Chalhoub. "Effects of Fuzzy-Tuning the Boundary Conditions on the Active Control of a Single-Link Flexible Robotic Manipulator." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15935.

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A new approach has been proposed in this study to effectively control the rigid and flexible motions of a single-link robotic manipulator. This is done by developing a two-layered control strategy. The upper layer is solely concerned with the process of fuzzy-tuning the boundary conditions of the flexible link. The rationale is to exploit the advantages, attributed to varying the boundary conditions of the compliant beam, in rendering the joint controller more effective in suppressing the unwanted vibrations of the arm. The lower or second layer of the control strategy is considered herein to be either a conventional or a fuzzy-tuned control scheme. Its main task is to determine the appropriate joint control torque needed to perform good set-point tracking while suppressing the undesired vibrations of the robot. The digital simulation results confirm that the process of fuzzy-tuning the boundary conditions of the flexible link has a tendency to significantly enhance the capability of the joint controller in suppressing the unwanted vibrations of the manipulator.
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Yang, Shaoqiong, and Nan Jiang. "Wavelet analysis to detect multi-scale coherent eddy structures and intermittency in turbulent boundary layer." In 2011 Eighth International Conference on Fuzzy Systems and Knowledge Discovery (FSKD 2011). IEEE, 2011. http://dx.doi.org/10.1109/fskd.2011.6019659.

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Erbatur, Kemalettin, and Berk Calli. "Fuzzy Boundary Layer Tuning as Applied to the Control of a Direct Drive Robot." In IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society. IEEE, 2007. http://dx.doi.org/10.1109/iecon.2007.4460264.

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Yong-Chao, Wang, Cui Ya-Long, Cao Li-Jia, Cai Guang-Bin, and Hu Xiao-Xiang. "Fuzzy boundary layer adaptive sliding mode controller design for a hypersonic vehicle based on tangent reaching law." In 2014 International Conference on Mechatronics and Control (ICMC). IEEE, 2014. http://dx.doi.org/10.1109/icmc.2014.7231540.

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Zaeri, Amir Hossein, Samsul Bahari Mohd-Noor, Maryam Mohd Isa, Farah Saleena Taip, and Aida Esmaeilian Marnani. "Disturbance Rejection for a 2-DOF Nonlinear Helicopter Model by Using MIMO Fuzzy Sliding Mode Control with Boundary Layer." In 2012 3rd International Conference on Intelligent Systems, Modelling and Simulation (ISMS). IEEE, 2012. http://dx.doi.org/10.1109/isms.2012.129.

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Bai, Shengjian, Pinhas Ben-Tzvi, Qingkun Zhou, and Xinsheng Huang. "Fuzzy Sliding Mode Control of a Flexible Spacecraft With Input Saturation." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12778.

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This paper presents the dynamic modeling and fuzzy sliding mode control (FSMC) for a spacecraft with flexible appendages. A first-order approximate model (FOAM) of the flexible spacecraft system is formulated by using Hamilton’s principles and assumed mode method (AMM), taking into account the second-order term of the coupling deformation field. The use of classical Sliding Mode Control (SMC) presents a major problem that appears in the form of chattering. For highly flexible structural models, ideal sliding surface producing pure rigid body motion may not be achievable. In this paper, the discontinuity in the sliding mode controller is smoothened inside a thin boundary layer by using fuzzy logic (FL) techniques so that the chattering phenomenon is effectively reduced. The robustness of SMC only holds in the sliding mode domain (SMD). However, when the amplitude of the actuators is limited, SMD will be restricted to some local domain near zero on the switching surface. Control input saturation is also explicitly considered in the FSMC approach. The new features and advantages of the proposed approach are the use of new dynamic equations of motion of flexible spacecraft systems, and the design of FSMC by taking into account the control input saturation. To study the effectiveness of the corresponding control scheme, the classical SMC case is also developed for the control system. Numerical simulations are performed to show that rotational maneuvers and vibration suppression are accomplished in spite of the presence of disturbance torques, model uncertainty and control saturation nonlinearity.
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Dou, Jingyang, Jinglai Wu, and Yunqing Zhang. "Stability-Based Coordinated Control for Distributed Drive Electric Vehicle Trajectory Tracking and Handling Stability." In WCX SAE World Congress Experience. SAE International, 2025. https://doi.org/10.4271/2025-01-8307.

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<div class="section abstract"><div class="htmlview paragraph">To address the issue of poor yaw stability in distributed drive electric vehicles under extreme trajectory tracking conditions, this paper proposes a novel control approach that coordinates upper-layer trajectory tracking and stability control with lower-layer active front steering (AFS) and direct yaw moment control (DYC). Firstly, a stability domain boundary is defined in the <span class="formula inline"><math display="inline" id="M1"><mi>β</mi><mo>−</mo><mover accent="true"><mi>β</mi><mo>̇</mo></mover><mspace width="0.25em"/></math></span>phase plane, and the instability factor is derived based on boundary line characteristics. This factor is used as a weight in the objective function to establish a model predictive control (MPC) for trajectory tracking and handling stability, thereby adjusting the control target weights for both objectives. Secondly, fuzzy logic is used to change the boundary of the phase plane transition field according to the vehicle state to dynamically adjust the intervention timing of the stability control, while AFS and DYC control are used to modify the front wheel steering angle and yaw moment control in the MPC model, and ultimately the torque is distributed to the four wheels. Simulation results show that this control method significantly improves vehicle stability under extreme conditions compared to single-objective MPC, achieving a comprehensive enhancement in trajectory tracking accuracy and vehicle yaw stability performance.</div></div>
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Lee, Hsin-Hung. "A Novel Calibration Method and Computer Simulation for Multi-hole Pitot Tubes." In NCSL International Workshop & Symposium. NCSL International, 2014. http://dx.doi.org/10.51843/wsproceedings.2014.18.

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Greenhouse gas emissions have been regarded as a global challenge and several national metrology institutes have started research on this topic. Smokestacks are one of the main emission sources and its flow measurements draw much attention due to the unstable flow conditions and complex gas composition. Pitot tubes are widely used in the environmental analysis. However, the traditional pitot tube can only provide one-dimensional flow velocity and the measurement locations also need to be placed with care. Multi-hole pitot tubes have been claimed that it can be applied to three-dimensional swirl flow measurements in the smokestack and provides more accurate results. The main drawback for using multi-hole pitot tubes is the time-consuming and complex calibration procedures before implementation. The possible way to significantly reduce the time and costs is to establish an automatic calibration traversing system and programmable calibration method. Moreover, the latest research also revealed that flow separation and hysteresis occurred during multi-hole pitot tube calibration and resulted in discrepancies in the repeatability testing. Therefore, flow visualization, surface pressure analysis and calibration data modeling need to be further studied in order to establish appropriate measurement technology for quantifying the greenhouse gas emissions effectively. In this paper, ANFIS (Adaptive-Network-based Fuzzy Inference System) method was first applied to multi-hole pitot tube calibration modeling owing to its capability of efficient learning, easy implementation and excellent explanation through fuzzy rules. The results showed that ANFIS method can help identify the dominant parameters and construct the network of pitot tube calibration parameters among non-dimensional pressure coefficients, flow angles and flow velocity. Additionally, a commercial CFD software, ANSYS Fluent 14, was used to simulate the flow hysteresis during pitot tube calibration. The simulation was carried out by unsteady computation and the Shear Stress Transport (SST) ê-ù turbulence model was also adopted to study the adverse pressure gradients and flow separation. The simulation results showed that the location of recirculation area can be identified by the contour of negative X velocity and vorticity. It’s helpful for elucidating the laminar boundary layer separation and the behavior of flow transition on the pitot tube when flow hysteresis occurs.
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Reports on the topic "Fuzzy boundary layer"

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Aroonmanakun, Wirote. Thoughts on word and sentence segmentation in Thai. Chulalongkorn University, 2007. https://doi.org/10.58837/chula.res.2007.92.

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This paper discusses problems of word and sentence segmentation in Thai. Disagreements on word segmentation are caused mostly from compound words. To set a standard resource and tool of word segmentation, we suggest that only simple words and true compound words should be segmented in the process of word segmentation. Other compounds can be grouped later by the same means as multiword identification in other languages. Sentence segmentation is also difficult because the boundary of sentence in Thai is fuzzy. We suggest that a discourse should be seen as a combination of clauses rather than sentences. Some discourse clues then can be used to segment these discourse units. The result from sentence segmentation module could be a sequence of segments composed of clauses, which then can be constructed into the discourse structure.
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