Applying Optimized Support Vector Regression Models for Prediction of Tunnel Boring Machine Performance     

Hadi Fattahi  Nima Babanouri 《Geotechnical and Geological Engineering》2017,35(5):2205-2217

One of the main factors in the effective application of a tunnel boring machine (TBM) is the ability to accurately estimate the machine performance in order to determine the project costs and schedule. Predicting the TBM performance is a nonlinear and multivariable complex problem. The aim of this study is to predict the performance of TBM using the hybrid of support vector regression (SVR) and the differential evolution algorithm (DE), artificial bee colony algorithm (ABC), and gravitational search algorithm (GSA). The DE, ABC and GSA are combined with the SVR for determining the optimal value of its user defined parameters. The optimization implementation by the DE, ABC and GSA significantly improves the generalization ability of the SVR. The uniaxial compressive strength (UCS), average distance between planes of weakness (DPW), the angle between tunnel axis and the planes of weakness (α), and intact rock brittleness (BI) were considered as the input parameters, while the rate of penetration was the output parameter. The prediction models were applied to the available data given in the literature, and their performance was assessed based on statistical criteria. The results clearly show the superiority of DE when integrated with SVR for optimizing values of its parameters. In addition, the suggested model was compared with the methods previously presented for predicting the TBM penetration rate. The comparative results revealed that the hybrid of DE and SVR yields a robust model which outperforms other models in terms of the higher correlation coefficient and lower mean squared error.  相似文献   

Bumping against a Gas Ceiling   总被引：1，自引：0，他引：1  

Hadi Dowlatabadi 《Climatic change》2000,46(3):391-407

The adoption of physical thresholds as a ceiling for permitted climate change sidesteps contentious issues such as: policy cost, impact valuation, discounting and equity. In this paper I offer some reflections on the concept of tolerable climate change. I also use an integrated climate assessment model (ICAM-3) to demonstrate how uncertainties in our understanding of socioeconomic and earth systems reduce the probability of success in keeping climate change within a pre-defined tolerable range. Finally, I explore the implications of socioeconomic thresholds for welfare loss in pursuit of a climate policy (e.g., tax rebellions). Crossing such regional socioeconomic thresholds will lead to local failures to pursue climate change mitigation policies — increasing the probability of straying beyond the tolerable window of global climate change. Given various uncertainties and the dynamics of the socioeconomic and the earth systems, the odds of success in staying within a climate change window of T 2°C, and T/yr 0.015°C are estimated to be no higher than 25% over the next century. A risk-risk tradeoff approach appears to hold promise, but while adoption of a larger window of tolerance increases the probability of success, it also opens the window specification criteria to contention.  相似文献   

The effect of surface profile, rock strength and pretension load on bending behaviour of fully grouted bolts     

Hossein Jalalifar  Naj Aziz  Muhammad Hadi 《Geotechnical and Geological Engineering》2006,24(5):1203-1227

Fully encapsulated rock bolting has, in recent years, become a universally accepted system of ground reinforcement in mining and tunnel construction. The application of bolting systems extends both to rebar as well as cable bolting. The effectiveness of the bolt application has been studied in shear, both by laboratory tests as well as by numerical modeling. A specially constructed double shearing apparatus (DSA) was used to examine the shearing behaviour of a bolt installed perpendicularly across two joints. The experimental study was complemented with three-dimensional numerical analysis. Parameters examined include, the effect of reinforced material on tension/compression zones along the sheared bolt, shear resistance, shear displacement and induced strains and stresses during bolt bending process. The study was undertaken at both free load and pretension conditions. The conclusions drawn from the study were the level of bolt resistance to shear was influenced by bolt profile configuration, the strength of the rock or medium influenced the level of load generated on the bolt and the increased bolt pretension contributed to increased shearing load of the bolted medium. The numerical simulation of the bolt/medium interaction and deformational behaviour were found to be in close agreement with the experimental test results.  相似文献   

Challenges in financing public sector low-carbon initiatives: lessons from private finance for a school district in British Columbia,Canada     

Thor Jensen  Hadi Dowlatabadi 《Climate Policy》2018,18(7):878-888

Governments are major investors in climate change mitigation, but aversion to public indebtedness has led to reliance on private finance to deliver public assets. Compounding this challenge, financing through Energy Service Contracts is ruled out by accounting rules. With public and traditional private funding avenues closed, government departments have sought contracts that do not disclose the full cost of borrowing, such as the Public–Private Partnership (PPP) described in this case study. We unpack the utility contract filed with the provincial regulator to show that circumventing budgetary constraints cost the Delta School Board (DSB) 8.75% per annum on borrowed private funds while public finance would have cost 4%pa. All levels of the public sector are keen to play their role in climate mitigation. Climate policy is about not passing our burden of unbridled fossil fuel use and greenhouse gas emissions to future generations. If we do not exempt public sector capital investments for decarbonization from deficit regulations, we risk passing an unnecessary economic burden to future generations.

Key policy insights

• Transition to a low-carbon economy requires public sector investments that exceed budget deficit regulations and political aversion in many jurisdictions;

• Private–Public Partnerships are currently viewed as the solution to this self-imposed fiscal constraint;

• PPPs without clear performance targets or contractual templates will expose less experienced public sector investors to high costs and emissions above expectations.

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Green biocompatible approach to reduce the toxic gases and dust caused by the blasting in surface mining     

Jafar Abdollahisharif  Ezzeddin Bakhtavar  Hadi Nourizadeh 《Environmental Earth Sciences》2016,75(3):191

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Multi-well and multi-tracer tests to characterize the groundwater aquifers in southern Kuwait     

K. Hadi  U. Saravana Kumar  M. Al-Senafy  A. Mukhopadhyay  A. Al-Khalid  K. Al-Fahad  H. Bhandary 《Environmental Earth Sciences》2016,75(20):1340

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Tschermak fractionation in calc-alkaline magmas: the Eocene Sabzevar volcanism (NE Iran)     

Federico Lucci  Federico Rossetti  John Charles White  Hadi Shafaii Moghadam  Alireza Shirzadi  Mohsen Nasrabady 《Arabian Journal of Geosciences》2016,9(10):573

Calc-alkaline arc magmatism at convergent plate margins is volumetrically dominated by metaluminous andesites. Many studies highlighted the importance of differentiation via fractionation processes of arc magmas, but only in the last decades, it has been demonstrated that not all rock-forming minerals may affect the evolution of calc-alkaline suites. In particular, a major role exerted by Al-rich hornblende amphibole as fractionating mineral phase has been documented in many volcanic arc settings. The aim of this work is to understand the role of the Tschermak molecule (CaAlAlSiO₆) hosted in the hornblende and plagioclase fractionation assemblage in driving magma differentiation in calc-alkaline magmatic suites. We explore this issue by applying replenishment–fractional crystallization (RFC) and rare earth element–Rayleigh fractional crystallization (REE-FC) modeling to the Sabzevar Eocene (ca. 45–47 Ma) calc-alkaline volcanism of NE Central Iran, where hornblende-controlled fractionation has been demonstrated. Major element mass balance modeling indicates RFC dominated by a fractionating assemblage made of Hbl_52.0–52.5 + Pl_44.1–44.2 + Ttn_3.3–3.9 (phases are expressed on total crystallized assemblage). REE-FC modeling shows, instead, a lower degree of fractionation with respect to RFC models that is interpreted as due to hornblende and plagioclase resorption by the residual melt. Calculations demonstrate that fractionation of the Tschermak molecule can readily produce dacite and rhyolite magmas starting from a calc-alkaline andesite source (FC = ca. 30 %). In particular, the Tschermak molecule controls both the heavy rare earth elements (HREE) and light rare earth element (LREE) budgets in calc-alkaline differentiation trends.  相似文献   

The analysis of trend variations of reference evapotranspiration via eliminating the significance effect of all autocorrelation coefficients     

Babak Amirataee  Majid Montaseri  Hadi Sanikhani 《Theoretical and Applied Climatology》2016,123(1-2):131-139

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Utilization of bituminous limestone ash from EL-LAJJUN area for engineering applications   总被引：1，自引：1，他引：0  

Nafeth A. Rahman A. Hadi  Hani N. Khoury  Mohammad R. Suliman 《Acta Geotechnica》2008,3(2):139-151

The following work aims at minimizing the environmental impact of the solid wastes (ash) that is produced after the utilization of the bituminous limestone in thermal power stations and /or retort processes. Limy ash has been prepared from the El-Lajjun bituminous limestone by direct combustion at 1,200, 950, and 525°C respectively. The laboratory tests have been selected with respect to construction needs and possible post construction conditions. Utilization of the various types of ash in the stabilization problematic soils from Jordan as brown soils and the clayey marl has revealed optimum results. The unconfined compressive strength of the parent brown soil and the clayey marl has been raised from 5 kg/cm² to 50 and 25 kg/cm², respectively. The CBR value has been raised from 4.5 to 150% for both problematic soil types. Various mortars and construction elements can be produced at normal room curing temperature without the use of ordinary Portland cement (OPC). Low quality sub-base and base course can be mixed with ash to produce cement treated base (CTB) and roller compacted concrete (RCC) without OPC. Durable pavements, embankments can be constructed with very long life and low cost. CTB and RCC utilizing ash can be used in dam construction instead of normal soil in earth fill dams. The high alkalinity of El-Lajjun ash is considered as a disadvantage to be utilized in normal concrete mixes for structural purposes. Ash only can be mixed with aggregates to produce lean concrete like for blinding purposes to be prepared for foundation activities.  相似文献   

Prediction of Blast-Induced Ground Vibration in a Mine Using Relevance Vector Regression Optimized by Metaheuristic Algorithms     

Fattahi  Hadi  Hasanipanah  Mahdi 《Natural Resources Research》2021,30(2):1849-1863

Natural Resources Research - Prediction of ground vibration induced by blasting operations is a crucial challenge to engineers working in surface mines. This study aims to assess the efficiency of...  相似文献