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Accurate short-term traffic flow prediction plays an important role in traffic guidance and traffic safety. In order to solve the problem that traffic flow is difficult to predict because of the sharp nonlinearity and randomness, ...
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Accurate short-term traffic flow prediction plays an important role in traffic guidance and traffic safety. In order to solve the problem that traffic flow is difficult to predict because of the sharp nonlinearity and randomness, a deep learning framework, i.e., the temporal convolutional network (TCN) was explored to capture the nonlinear spatiotemporal characteristics of traffic flow. By adjusting the hyper-parameters of TCN, a traffic flow predictor is proposed. Besides, this paper adopts a method to calculate the designated cross-section traffic volume of freeways from toll data, which makes up for the inability to obtain traffic volume at some cross-section locations due to damage or lack of traffic detection equipment. Through data merging, data cleaning, data reconstruction, data filtering, a traffic flow data set which was selected as the data input with a time interval of 15 min was constructed based on the toll data of Shaanxi Province freeway network from December 2018 to April 2019 as the data source. The TCN model was compared with the SVM, SAE, LSTM and GRU models in terms of mean absolute error (MAE) and root mean square error (RMSE). The prediction results of multiple cross-sections showed the TCN model performs best with superior prediction accuracy, which indicate the TCN model has good robustness and generalization ability. The traffic volume calculation algorithm may provide a practical method for deriving the traffic volume without installing any additional regularly maintained detectors and equipment on the freeway. And the prediction results of TCN model can provide strong support for traffic control and traffic induction.
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In 2000, the International Standards Organisation (ISO) re-allocated priority to an Arctic Offshore Structures Standard. Canada, having an active process and committees in place for Arctic Offshore Structures, took the initiat...
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In 2000, the International Standards Organisation (ISO) re-allocated priority to an Arctic Offshore Structures Standard. Canada, having an active process and committees in place for Arctic Offshore Structures, took the initiative to propose a new work item to ISO. In response to the Canadian initiative, ISO Technical Committee 67 (TC67), Sub-Committee 7 (SC7 - Offshore Structures) approved, in 2002, a New Work Item Proposal to develop a new code related to "Petroleum and natural gas industries - Arctic offshore structures". An objective of this code was also to harmonise existing international offshore codes and standards related to the Arctic. SC7 established Working Group 8 (WG 8) in response to the approval of this New Work Item Proposal. WG8 held its first meeting in July 2002, in Toronto, Canada. All countries with offshore regions that experience ice covered waters, or have an interest in these regions, were requested to provide country representatives and technical experts to staff respectively WG8 and the Technical Panels formed by WG8 to actually prepare the document. This paper describes the WG8 organizational structure, its scope of work, current membership, delivery schedule, and progress to date.
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As the main exploitation mean of low permeability reservoirs,multistage fracturing plays a significant role in horizontal well.However,due to the multi-stage fracturing technology lack of focused research on crack interaction phen...
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As the main exploitation mean of low permeability reservoirs,multistage fracturing plays a significant role in horizontal well.However,due to the multi-stage fracturing technology lack of focused research on crack interaction phenomenon,limiting its further development.In this paper,considering the basis of rock and soil mechanics,flow mechanics theory,the fluid-solid coupling and combining with extended finite element method(XFEM)to simulate the fracture propagation of 2-4 vertical cracks for simultaneous fracturing in horizontal well.Based on the fracture morphology,optimizing the number of fractures,cluster spacing and segment spacing by comparing the crack width of deflection point with the crack width of injection point.The simulation results are applied in field for verification.The study results are as follows:Selecting 2-3 cracks per segment can efficiently satisfy the requirement of production;the optimal cluster spacing of simultaneous fracturing for two fractures is 20-30 m;the optimal cluster spacing of simultaneous fracturing for three fractures is 30-40 m;the optimal segment spacing is 30-40 m.The results suggested as above illustrate that the more the number of fractures,the better the effect of multistage fracturing is not correct.Meanwhile,the reasonable fracture spacing can effectively reduce the negative impact of crack interaction phenomenon.The research method and optimal parameters proposed in this paper provides a theoretical basis for practical production in horizontal well.
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Discussions on community & multi-function-based aged care in China are mostly converged on and manifested as follows, (1) The "software" level as in policies, models, industry and even management instead of the "hardware" studies as in the living space of the elders where a hierarchy system and well-thought-out opinions are absent; (2) Fearful tendency of administerization and institutionalization. Especially the construction of facilities for the elders is mostly oriented by the "top-down" subjective analysis and evaluation. Studi...
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Discussions on community & multi-function-based aged care in China are mostly converged on and manifested as follows, (1) The "software" level as in policies, models, industry and even management instead of the "hardware" studies as in the living space of the elders where a hierarchy system and well-thought-out opinions are absent; (2) Fearful tendency of administerization and institutionalization. Especially the construction of facilities for the elders is mostly oriented by the "top-down" subjective analysis and evaluation. Studies on the aged-users-centric Post Occupancy Evaluation (POE) of existing community-based nursing homes still remain insufficient, and there is a lack of an evaluation system of infrastructure for the elders' adaptability to their living conditions. An advocacy shall be called upon everyone in China for concerted efforts in studying how to improve the adaptability of services for the aged to the space of facilities, and providing the elders with an easeful and upbeat living environment. Based on the fundamental principle of "Aging in Place" of the adaptability of the living conditions of nursing homes, this paper presents a humble opinion regarding the ideas of space design from the perspectives of safety, comfort and positivity, and hopefully provides a foundation for the discussions of the likes of such studies.
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Production of sand(rock debris and proppant)during fracturing fluid flowback is a serious problem for low-permeability reservoir.The sand production control techniques mainly includes mechanical and chemical method.In this paper,t...
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Production of sand(rock debris and proppant)during fracturing fluid flowback is a serious problem for low-permeability reservoir.The sand production control techniques mainly includes mechanical and chemical method.In this paper,the main object is to evaluate the proppant production control performance of sand consolidation agent with different types.The sand consolidation agent S has the optimal performance compared with the P and U.The fiber can effectively reduce the proppant flowback quality.The optimal length and concentration of the fiber are 5 mm and 0.5%,respectively.The performance of the mixture of fiber and sand consolidation agent S(Fiber+S)is better than that of sand consolidation agent S and fiber alone.The proppant flowback quality after mixing the Fiber+S was reduced by more than 10 times compared with the case where no sand production control measures were taken.The growth rate of proppant flowback quality after mixing Fiber+S becomes larger when the flowback rate reaches 800 mL/min.The flowback rate is increased by four times compared with the case without sand production control measures.The research results show that the Fiber+S can effectively reduce the proppant flowback quality and greatly increase the fracturing fluid flowback rate.
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The old town of Liaocheng has followed the typical pattern of a township dating back to the Song Dynasty, which is formed by the mix of elements including Liaocheng's geographical features, its social-economic and cultural backgro...
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The old town of Liaocheng has followed the typical pattern of a township dating back to the Song Dynasty, which is formed by the mix of elements including Liaocheng's geographical features, its social-economic and cultural background and its history of human settlement activities, and is defined by of the formation of human habitation, featuring with significant geographical and cultural characteristics of a river town north of the Yellow River and being an important component of the historical and cultural heritage resources in western Shandong Province.As modern economic development goes on, while Liaocheng is about to initiate its renewal development of the core area and the surrounding area of the old town, how to deal with the relationship between its cultural inheritance versus urban development would be a very urgent and practical problem throughout the whole process of heritage preservation for historical street districts and urban development.In this paper, within the context of urbanization, preservation of historical and cultural heritage of the canal in the ancient city of Liaocheng versus the development and renewal of its old town are studied and explored about, combing through the developmental threads of this ancient city with the hope of providing some valuable lessons for preservation issues around other ancient towns.
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