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Combinatorial Algorithms for Reverse Selective Undesirable Center Location Problems on Cycle Graphs

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Journal of the Operations Research Society of China 2017年第3期5卷 347-361页

作者： Roghayeh Etemad behrooz Alizadeh Department of Applied Mathematics Faculty of Basic SciencesSahand University of TechnologyTabrizIran

This paper deals with a general variant of the reverse undesirable(obnoxious)center location problem on cycle *** a‘selective’subset of the vertices of the underlying cycle graph as location of the existing customers,the task is to modify the edge lengths within a given budget such that the minimum of distances between a predetermined undesirable facility location and the customer points is maximized under the perturbed edge *** develop a combinatorial O(n log n)algorithm for the problem with continuous *** the uniform-cost model,we solve this problem in linear time by an improved ***,exact solution methods are proposed for the problem with integer modifications.

关键词： Undesirable center location Reverse optimization Combinatorial optimization Time complexity

Optimal Algorithms for Integer Inverse Undesirable p-Median Location Problems on Weighted Extended Star Networks

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Journal of the Operations Research Society of China 2021年第1期9卷 99-117页

作者： Esmaeil Afrashteh behrooz Alizadeh Fahimeh Baroughi Department of Applied Mathematics Faculty of Basic SciencesSahand University of TechnologyTabrizIran

This paper is concerned with the problem of modifying the edge lengths of a weighted extended star network with n vertices by integer amounts at the minimum total cost subject to be given modification bounds so that a set of p prespecified vertices becomes an undesirable p-median location on the perturbed *** call this problem as the integer inverse undesirable p-median location *** combinatorial algorithms with O(p2n logn)and O(p2(n logn+n log nmax))running times are proposed for solving the problem under the weighted rectilinear and weighted Chebyshev norms,***,it is shown that the problem under the weighted sum-type Hamming distance with uniform modification bounds can be solved in O(p-n log n)time.

关键词： Undesirable p-median location Combinatorial optimization Inverse optimization Time complexity

Analysis of cohesive particles mixing behavior in a twin-paddle blender:DEM and machine learning applications

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Particuology 2024年第7期90卷 350-363页

作者： behrooz Jadidi Mohammadreza Ebrahimi Farhad Ein-Mozaffari Ali Lohi Department of Chemical Engineering Toronto Metropolitan University350 Victoria StreetToronto M5B 2K3Canada

This research paper presents a comprehensive discrete element method(DEM)examination of the mixing behaviors exhibited by cohesive particles within a twin-paddle blender.A comparative analysis between the simulation and experimental results revealed a relative error of 3.47%,demonstrating a strong agreement between the results from the experimental tests and the DEM *** main focus centers on systematically exploring how operational parameters,such as impeller rotational speed,blender's fill level,and particle mass ratio,influence the *** investigation also illustrates the significant influence of the mixing time on the mixing *** gain a deeper understanding of the DEM simulation findings,an analytical tool called multivariate polynomial regression in machine learning is *** method uncovers significant connections between the DEM results and the operational parameters,providing a more comprehensive insight into their *** multivariate polynomial regression model exhibited robust predictive performance,with a mean absolute percentage error of less than 3%for both the training and validation sets,indicating a slight deviation from actual *** model's precision was confirmed by low mean absolute error values of 0.0144(80%of the dataset in the training set)and 0.0183(20%of the dataset in the validation set).The study offers valuable insights into granular mixing behaviors,with implications for enhancing the efficiency and predictability of the mixing processes in various industrial applications.

关键词： Machine learning Granular mixing Discrete element method Mixing kinetics and mechanism Cohesive particles

Dynamic rupture and crushing of an extruded tube using artificial neural network(ANN)approximation method

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Journal of Central South University 2016年第4期23卷 869-879页

作者： Javad Marzbanrad behrooz Mashadi Amir Afkar Mostafa Pahlavani School of Automotive Engineering Iran University of Science and TechnologTehranIran Faculty of Electrical Mechanical and Construction EngineeringDepartment of Automotive EngineeringStandard Research Institute(SRI)Karaj P.O.Box 31745-139Iran

A numerical study of the crushing of thin-walled circular aluminum tubes has been carried out to investigate the crashworthiness behaviors under axial impact loading. These kinds of tubes are usually used in automobile and train structures to absorb the impact energy. Previous researches show that thin-walled circular tube has the highest energy absorption under axial impact amongst different structures. In this work, the crushing between two rigid flat plates and the tube rupture by 4 and 6 blades cutting tools is modeled with the help of ductile failure criterion using the numerical method. The tube material is aluminum EN AW-7108 T6 and its length and diameter are 300 mm and 50 ram, respectively. Using the artificial neural network （ANN）, the most important surfaces of energy absorption parameters, including the maximum displacement of the striker, the maximum axial force, the specific energy absorption and the crushing force efficiency in terms of impact velocity and tube thickness are obtained and compared to each other. The analyses show that the tube rupture by the 6 blades cutting tool has more energy absorption in comparison with others. Furthermore, the results demonstrate that tube cutting with the help of multi-blades cutting tools is more stable, controllable and predictable than tube folding.

关键词： thin-walled structure rupture energy absorption ductile failure criterion neural network

Semi-empirical modeling of volumetric efficiency in engines equipped with variable valve timing system

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Journal of Central South University 2016年第12期23卷 3132-3142页

作者： Mostafa Ghajar Amir Hasan Ka Kaee behrooz Mashadi Department of Automotive Engineering Iran university of Science and Technology

Volumetric efficiency and air charge estimation is one of the most demanding tasks in control of today's internal combustion ***,using three-way catalytic converter involves strict control of the air/fuel ratio around the stoichiometric point and hence requires an accurate model for air charge ***,high degrees of complexity and nonlinearity of the gas flow in the internal combustion engine make air charge estimation a challenging *** is more obvious in engines with variable valve timing systems in which gas flow is more complex and depends on more functional *** results in models that are either quite empirical(such as look-up tables),not having interpretability and extrapolation capability,or physically based models which are not appropriate for onboard *** these problems,a novel semi-empirical model was proposed in this work which only needed engine speed,load,and valves timings for volumetric efficiency *** accuracy and generalizability of the model is shown by its test on numerical and experimental data from three distinct *** test errors are 0.0316,0.0152 and 0.24 for the three engines,*** the performance and complexity of the model were compared with neural networks as typical black box *** the complexity of the model is less than half of the complexity of neural networks,and its computational cost is approximately 0.12 of that of neural networks and its prediction capability in the considered case studies is usually *** results show the superiority of the proposed model over conventional black box models such as neural networks in terms of accuracy,generalizability and computational cost.

关键词： engine modeling modeling and simulation spark ignition engine volumetric efficiency variable valve timing

Ground behaviour analysis,support system design and construction strategies in deep hard rock mining-Justified in Western Australian’s mines

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 1-20页

作者： behrooz Rahimi Mostafa Sharifzadeh Xia-Ting Feng Department of Mining and Metallurgical Engineering Western Australian School of Mines:MineralsEnergy and Chemical Engineering(WASM-MECE)Curtin UniversityKalgoorlieWM6430Australia Key Laboratory of Ministry of Education for Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China

Development of deep underground mining projects is crucial for optimum extraction of mineral *** main challenges at great depth are high rock stress levels,seismic events,large-scale deformation,sudden failures and high temperatures that may cause abrupt and unpredictable instability and collapse over a large *** this paper,a ground control and management strategy was presented corresponding to the three stages of projects:strategic design,tactical design and operational *** design is results in preparing a broad plan and primary design for mining *** tactical design is to provide detail design such as stabilisation *** design stage is related to monitoring and updating design *** most effective ground control strategies in this stage are maintenance,rehabilitation,monitoring and contingency ***,a new procedure for design of ground support systems for deep and hard rock was *** main principles are:static and/or dynamic loading types,determination of loading sources,characterisation of geological conditions and the effects of orientation of major structures with openings,estimation of ground loading factor,identification of potential primary and secondary failures,utilisation of appropriate design analysis methods,estimation of depth failure,calculation of the static and/or dynamic demand ground support capacity,and selection of surface and reinforcement *** force is the dominant loading force in low-level *** high stress level failure mechanism becomes more complex in rock mass *** this condition,a variety of factors such as release of stored energy due to seismic events,stress concentration,and major structures influence on ground behaviour and judgement are very *** key rock engineering schemes to minimise the risk of failures in high-stress levels at great depth involve depressurisation and quality control of ***

关键词： Ground management Support system design Sequential excavation Stress management Geotechnical monitoring Deep underground mines

An Efficient Method to Estimate Admittance of Black-boxed Inverter-based Resources for Varying Operating Points

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 421-426页

作者： Weihua Zhou Bin Liu Nabil Mohammed behrooz Bahrani Department of Electrical and Computer Systems Engineering Monash UniversityMelbourne 3800Australia Energy Centre Commonwealth Scientific and Industrial Research Organisation(CSIRO)Newcastle 2300Australia.He is now with the Network Planning DivisionTransgridSydney 2000Australia

Traditional analytical approaches for stability assessment of inverter-based resources(IBRs),often requiring detailed knowledge of IBR internals,become impractical due to IBRs’proprietary *** measurements,relying on electromagnetic transient simulation or laboratory settings,are not only time-intensive but also operationally inflexible,since various non-linear control loops make IBRs’admittance models operating-point ***,such admittance measurements must be performed repeatedly when operating point *** avoid time-consuming and cumbersome measurements,admittance estimation for arbitrary operating points is highly ***,existing admittance estimation algorithms usually face challenges in versatility,data demands,and *** this challenge,this letter presents a simple and efficient admittance estimation method for blackboxed IBRs,by utilizing a minimal set of seven operating points to solve a homogeneous linear equation *** studies demonstrate this proposed method ensures high accuracy across various types of *** accuracy is satisfying even when non-negligible measurement errors exist.

关键词： Admittance estimation black box inverterbased resource measurement error operating point

Spin-preserving chiral photonic crystal mirror

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Light(Science & Applications) 2020年第1期9卷 1787-1798页

作者： behrooz Semnani Jeremy Flannery Rubayet Al Maruf Michal Bajcsy Institute for Quantum Computing(IQC) University of WaterlooWaterloo N2L3G1 ONCanada Department of Electrical&Computer Engineering University of WaterlooWaterloo N2L3G1 ONCanada Department of Physics and Astronomy University of WaterlooWaterloo N2L3G1 ONCanada

Chirality refers to a geometric phenomenon in which objects are not superimposable on their mirror *** made of nanoscale chiral elements can exhibit chiroptical effects,such as dichroism for left-and right-handed circularly polarized light,which makes these structures highly suitable for applications ranging from quantum information processing and quantum optics to circular dichroism spectroscopy and molecular *** the same time,strong chiroptical effects have been challenging to achieve even in synthetic optical media,and chiroptical effects for light with normal incidence have been speculated to be prohibited in thin,lossless quasi-two-dimensional ***,we report an experimental realization of a giant chiroptical effect in a thin monolithic photonic crystal *** conventional mirrors,our mirror selectively reflects only one spin state of light while preserving its handedness,with a near-unity level of circular *** operational principle of the photonic crystal mirror relies on guided-mode resonance(GMR)with a simultaneous excitation of leaky transverse electric(TE-like)and transverse magnetic(TM-like)Bloch modes in the photonic crystal *** modes are not reliant on the suppression of radiative losses through long-range destructive interference,and even small areas of the photonic crystal exhibit robust circular *** its simplicity,the mirror strongly outperforms earlier reported structures and,contrary to a prevailing notion,demonstrates that near-unity reflectivity contrast for opposite helicities is achievable in a quasi-two-dimensional structure.

关键词： mirror crystal circular

Mixing and segregation assessment of bi-disperse solid particles in a double paddle mixer

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Particuology 2023年第3期74卷 184-199页

作者： behrooz Jadidi Mohammadreza Ebrahimi Farhad Ein-Mozaffari Ali Lohi Department of Chemical Engineering Ryerson University350 Victoria StreetTorontoM5B 2K3Canada

A double paddle blender's flow patterns and mixing mechanisms were analyzed using discrete element method(DEM)and *** mixing performance of this type of the blender containing bi-disperse particles has been rarely studied in the ***-Burman design of experiments(DoE)methodology was used to calibrate the DEM input ***,the impact of the particle number ratio,vessel fill level,and paddle rotational speed on mixing performance was investigated using the calibrated DEM *** mixing performance was assessed using relative standard deviation and segregation *** performance was significantly affected by the paddle rotational speed and particle number ***,the Peclet number and diffusivity coefficient were used to evaluate the mixing mechanism in the *** revealed that the diffusion was the predominant mixing mechanism,and the best mixing performance was observed when the diffusivity coefficients of 3 mm and 5 mm particles were almost equal.

关键词： Double paddle blender Discrete element method(DEM) Granular mixing Mixing kinetics and mechanism Bi-disperse solid particles