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Influence of pipeline structure on flow pattern classification and void fraction in offshore riser systems

OCEAN ENGINEERING 2025年 318卷

作者： Cao, Yeqi Xu, Qiang Wang, Chan Yu, Haiyang Guo, Liejin Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China

It is essential to study the influence of pipeline structure on flow pattern distribution and void fraction in riser systems to ensure the safe and stable operation of offshore pipelines. This paper reports the riser's local flow structures and average void fraction data at different overall flow patterns in a 1722 m long-distance pipeline Sshaped riser system. A flow pattern database is constructed for various riser systems including vertical upward pipe, horizontal/downward/upward-riser, and horizontal-downward-riser, totaling 4326 samples. When a horizontal/downward inlet is added to the vertical upward pipe, unstable flow is distributed in the region of slug flow in the vertical upward pipe;when a horizontal inlet is added to the downward-riser, the right boundary of unstable flow is moved to higher superficial gas velocity. The increase of riser height in the horizontal- downward-riser leads to the expansion of unstable flow to higher superficial gas-liquid velocities. The empirical flow pattern maps of vertical upward pipe and pipeline-riser for various pipe structures and fluid properties are proposed respectively, with accuracies of 93.1% and 80.3%. The correlation for predicting void fraction of the riser in the pipeline-riser system is established, and 92.43% of the data are within the error interval of +/-

关键词： pipeline-riser system Two-phase flow Flow pattern classification Void fraction pipeline structure Acronyms

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FPGA Implementation of DHT Through Parallel and pipeline structure

FPGA Implementation of DHT Through Parallel and Pipeline Str...

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11th International Conference of Computer Communication and Informatics (ICCCI)

作者： Jain, Riya Jain, Priyanka Delhi Technol Univ Dept Elect & Commun Engn Delhi India

ISBN: (纸本)9781728158754

A discrete Hartley transform (DHT) is a transform of discrete, periodic data similar to the discrete Fourier transform (DFT). This paper focuses on FPGA implementation of Discrete Hartley Transform for a sequence of length N, such that N = 4(r) where r>1. A proposed structure of DHT algorithm is designed in parallel as well as pipelined fashion using Verilog Hardware Description Language (VHDL). ZedBoard Zynq Evaluation and Development Kit was used to implement the same, and it was found that pipeline structure shows drastic improvement in terms of hardware utilization, power consumption and computation time (latency) required as compared to parallel structure.

关键词： parallel processing pipeline structure discrete Hartley transform DCT DST

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A pipeline structure for the sequential Boltzmann machine

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1999年第6期E82A卷 920-926页

作者： Zhu, HB Sasaki, M Inoue, T Kumamoto Univ Informat Proc Ctr Kumamoto 8608555 Japan Kumamoto Univ Fac Engn Dept Elect & Comp Engn Kumamoto 8608555 Japan

In this paper, by making good use of the parallel-transit-evaluation algorithm [11] and sparsity of the connection between neurons, a pipeline structure is successfully introduced to the sequential Boltzmann machine processor. The novel structure speeds up nine times Easter than the previous one[ll], with only the 12% rise in hardware resources under 10,000 neurons. The performance is confirmed by designing it using 1.2 mu m CMOS process standard cells and analyzing the probability of state-change.

关键词： sequential Boltzmann machine neural network pipeline structure parallel-transit-evaluation algorithm

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pipeline structure Schnorr-Euchner Sphere Decoding Algorithm

Pipeline structure Schnorr-Euchner Sphere Decoding Algorithm

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The 9th International Conference on Wireless Communications,Networking and Mobile Computing(WICOM 2013)

作者： Xinyu Mao Jianjun Wu Haige Xiang State Key Laboratory of Advanced Optical Communication Systems & Networks School of Electronics Engineering and Computer SciencePeking University

We propose a pipeline structure for Schnorr-Euchner sphere decoding algorithm in this article. It divides the search tree of the original algorithm into blocks and executes the search from block to block. When one block search of a signal is over, the part in the pipeline structure that processes this block search can load another signal and search. Several signals can be processed at the same time in one pipeline. Blocks are arranged to lower the whole complexity in the way that the previously search blocks are the blocks those have more probability to generate the final solution. Simulation experiment results show the average process delay can drop to the range from 48.77% to 60.18% in a 4-by-4 antenna system with 16QAM modulation, or from 30.31% to 61.59% in a 4-by-4 antenna system with 64QAM modulation.

关键词： Multiple-Input Multiple-Output System Schnorr-Euchner Sphere Decoding pipeline structure

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Damage Location Method of pipeline structure by Ultrasonic Guided Wave Based on Probability Fusion

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2024年 73卷 1-14页

作者： Zhang, Hong Teng, Feiyu Wei, Juntao Lv, Shanshan Zhang, Lei Zhang, Faye Jiang, Mingshun Shandong Univ Sch Control Sci & Engn Jinan 250061 Peoples R China

pipeline structures are widely used in construction, oil transportation, and other industrial fields, but with increasing service life, pipeline structures can develop health problems, such as perforations and cracks, which can cause pipeline fractures and bring serious safety accidents and economic losses if they are not detected at an early stage. Ultrasonic guided wave detection technology has been widely applied in precise damage detection of pipeline structures. To facilitate the grasp of structural health status, a pipeline structural damage imaging method combined with time-of-flight (ToF) compensation and probabilistic reconstruction is proposed. This method analyzes the response signals collected under different states, uses the correlation of the signals as the damage index, constructs an elliptical probability distribution, and determines the axial position of the damage. Afterward, using ToF as the characteristic parameter, a circular probability distribution is constructed to determine the circumferential location of the damage, and finally, the precise location of the damage is obtained. Forty-five test points were selected for the experiment. The average positioning error is 7 mm. The experimental results show that the method has certain recognition ability for single or multiple damages and has higher accuracy and stability compared to traditional probability reconstruction algorithms.

关键词： Damage position imaging pipeline structure probabilistic fusion structural health monitoring (SHM) ultrasonic guided wave

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Vibration Control of a pipeline structure Using Pounding Tuned Mass Damper

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JOURNAL OF ENGINEERING MECHANICS 2016年第6期142卷

作者： Song, G. B. Zhang, P. Li, L. Y. Singla, M. Patil, D. Li, H. N. Mo, Y. L. Sch Civil & Hydrol Engn Dalian 116023 Liaoning Peoples R China Forum Energy Technol Inc Houston TX 77024 USA Univ Houston Dept Mech Engn Houston TX 77004 USA Univ Houston Dept Civil & Environm Engn Houston TX 77004 USA

pipeline structures are often very flexible and susceptible to vibrations induced by many sources, such as vortex, external flow, and internal fluid flow. The pounding tuned mass damper (PTMD) is one device that may be employed to absorb and dissipate these undesired vibrations. The PTMD is a combination of the tuned mass damper and the impact damper. It utilizes the tuned mass to absorb kinetic energy and dissipates the absorbed energy through collisions. To examine the vibration control effectiveness of the PTMD, both numerical analysis and experimental study were performed. In the numerical analysis, a pounding force model was established based on the Hertz contact element. The motion equation of a pipeline structure incorporated with a PTMD was derived. Free vibration analysis and forced vibration analysis were performed. In the experimental study, an M-shaped pipeline was fabricated and installed with the PTMD. Due to safety issues the pipe was kept empty during the experiments. A free vibration experiment was first executed with and without PTMD to determine its effectiveness. Experimental data showed that the damping ratio of the pipeline structure was effectively increased when the PTMD was installed. Then the pipeline was subjected to harmonic excitation to attain resonance. Experimental results also showed that the PTMD effectively reduced the vibration of the pipeline structure. (C) 2016 American Society of Civil Engineers.

关键词： Tuned mass damper Impact damper Pounding tuned mass damper Vibration control pipeline structure

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A novel method for predicting fatigue crack propagation path of surface cracks in pipelines with a ConvLSTM-based model

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INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING 2025年 214卷

作者： Yu, Jianxing Su, Yefan Jin, Zihang Tian, Hanxu Zhao, Mingren Tianjin Univ State Key Lab Hydraul Engn Intelligent Construct & Tianjin 300072 Peoples R China Tianjin Univ Tianjin Key Lab Port & Ocean Engn Tianjin 300072 Peoples R China Beibu Gulf Univ Coll Mech & Marine Engn Qinzhou 535011 Guangxi Peoples R China

Accurate prediction for fatigue crack propagation path is crucial for ensuring the safe operation of pipelines. In this paper, we present a novel method for predicting fatigue crack propagation path of surface cracks in pipelines with a ConvLSTM-based model. The ConvLSTM-based model effectively correlates crack propagation paths with fatigue cycles. Moreover, we have improved the method which transforms simulation results into the dataset for machine learning. The prediction results prove the excellent predictive power of the improved method. To further validate the robustness of our model, we test its predictive capabilities on cases not included in the dataset. The proposed method accurately forecasts the fatigue crack propagation path in pipelines without requiring re-modeling and re-computational attempts. The result indicates that the proposed method significantly reduces computational time compared to the finite element method.

关键词： Fatigue crack propagation path Surface cracks pipeline structure Convolutional LSTM Spatiotemporal information

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Three-stage document-level entity relation extraction

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JOURNAL OF SUPERCOMPUTING 2025年第4期81卷 1-25页

作者： Lu, Ben Wang, Xianchuan Ming, Wenkai Wang, Xianchao Fuyang Normal Univ Sch Comp & Informat Engn Fuyang 236037 Anhui Peoples R China Fuyang Normal Univ Anhui Engn Res Ctr Intelligent Comp & Informat Inn Fuyang 236037 Anhui Peoples R China

Document-level entity relation extraction aims to identify all potential relations between entity pairs from unstructured text. To address challenges such as multi-mention entities, long-distance entity relations, and complex relation reasoning, this paper proposes a three-stage document relation extraction model (TSDRE) based on text coreference resolution and relation reasoning. Specifically, we first employ the CorefQA model to resolve referential pronouns within the document. Next, the document is segmented into sentences, and the PRGC model is utilized to extract sentence-level relations. Finally, leveraging information on potentially complex relations between entity pairs, relation reasoning, and supporting evidence encodes this information and uses it as input for the BERT model to determine possible relation categories of entity pairs. Experimental results demonstrate that on the DocRED, TSDRE achieves improvements of at least 0.18, 0.15, and 0.21 over other models in terms of validation set F1, test set F1 and lgnF1, respectively. On the DWIE, TSDRE achieves improvements of at least 0.81 and 0.35 for the validation set lgnF1 and the test set lgnF1, respectively. Results indicates that TSDRE excels in accurately and comprehensively extracting entity pair correlation information from documents.

关键词： Relation extraction Documentation Relational reasoning pipeline structure

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Transformer model combining cross-attention and self-attention guided by damage index for pipeline damage localization based on helical guided waves

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2025年 231卷

作者： Zhang, Hong Wang, Guoxiang Teng, Feiyu Lv, Shanshan Zhang, Lei Zhang, Faye Jiang, Mingshun Shandong Univ Sch Control Sci & Engn Jinan 250061 Peoples R China Qilu Univ Technol Shandong Acad Sci Sch Elect Engn & Automat Jinan 250061 Peoples R China Shandong Res Inst Ind Technol Jinan 250101 Peoples R China

The structural health monitoring technology based on ultrasonic guided waves (UGW) has broad application prospects in pipeline structural damage detection. This paper proposes a Transformer model based on damage index (DI) guidance and fusion of cross-attention and self-attention (DCAS-Transformer). Firstly, based on the principle of damage and guided waves, the DI representing the correlation between healthy signals and damaged signals is calculated and used as a weight to guide subsequent model training. This step enhances the correlation between signals and space. Secondly, based on cross-attention mechanism, a channel attention module is constructed to jointly input DI and signals into the module, achieving feature fusion and further emphasizing information related to damage. Finally, in the transformer module, based on its unique spatial attention mechanism, deep damage information extraction is achieved and damage localization is completed. The results show that the average localization error is 9.6 mm and the relative error is 1.92 %, and the proposed method performs well under different sensor layouts and noise levels. Compared with other deep learning methods, the proposed method has more stable performance and better generalization.

关键词： pipeline structure Helical guided wave Damage localization Transformer model Multiple attention mechanisms

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Synthesis and Realization of 3-D Orthogonal FIR Filters Using pipeline structures

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2018年第4期37卷 1669-1691页

作者： Poczekajlo, P. Wirski, R. T. Koszalin Univ Technol Fac Elect & Comp Sci Koszalin Poland

The authors present a novel design algorithm for 3-D orthogonal filters. Both separable and non-separable cases are discussed. In the separable case, the synthesis leads to a cascade connection of 1-D systems. In the latter case, one obtains 2-D systems followed by a 1-D one. Realization techniques for these systems are presented which utilize Givens rotations and delay elements. The results are illustrated by examples of separable and non-separable 3-D system designs, i.e., Gaussian and Laplacian filters.

关键词： 3-D Orthogonal FIR filter Synthesis pipeline structure Givens rotation

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