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Phase type delay distribution with PU return and sensing error in CR networks

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Journal of Central South University 2017年第10期24卷 2314-2321页

作者： mohammad reza Amini Hemati Farzad Department of Electrical Engineering College of EngineeringBorujerd BranchIslamic Azad UniversityBorujerdIran

Many studies have been done in cognitive radios to maximize the network efficiency. There is always a trade-off between sensing and transmission time which has been addressed fully in the literature. There is also some missed idle times during the waiting phase when secondary user finds the channel busy. Therefore, the longer the transmission time is, the higher the successfully delivered bits would be and the higher the missed idle times in the waiting stage would be expected. In this work, we formulate these missed idle times to addressed this trade-off. Furthermore, interference due to PU re-occupancy is modelled in successful transmitted time and in collision probability. Moreover, we derive secondary user's packet delay distribution using phase type model at which retransmission due to collision results from both sensing error and PU re-occupancy is considered. Thanks to derived delay distribution, any statistical moments of delay could be found as a closed form mathematical expression. These moments can be used as constraints for applications with delay sensitive packets. Numerical results are given to clarify the network metrics. Finally, the optimized values for sensing and transmission time are computed using genetic algorithm in order to maximize access efficiency.

关键词： phase type distribution spectrum sensing cognitive radio access efficiency

Border-search and jump reduction method for size optimization of spatial truss structures

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 123-134页

作者： Babak DIZANGIAN mohammad reza GHASEMI Department of Civil Engineering Velayat UniversityIranshahr ***Iran Department of Civil Engineering University of Sistan and BaluchestanZahedan ***Iran

This paper proposes a sensitivity-based border-search and jump reduction method for optimum design of spatial *** is considered as a two-phase optimization approach,where at the first phase,the first local optimum is found by few analyses,after the whole searching space is limited employing an efficient random strategy,and the second phase involves finding a sequence of local optimum points using the variables sensitivity with respect to corresponding values of constraints *** reach the global solution at phase two,a sequence of two sensitivity-based operators of border-search operator and jump operator are introduced until convergence is *** analysis is performed using numerical finite difference *** do structural analysis,a link between open source software of OpenSees and MATLAB was *** truss problems were attempted for optimization in order to show the fastness and efficiency of proposed *** were compared with those reported in the *** shows that the proposed method is competitive with the other optimization methods with a significant reduction in number of analyses carried.

关键词： optimum design sensitivity analysis reduction method spatial tresses OpenSees

Second-order cone AC optimal power flow: convex relaxations and feasible solutions

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Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 268-280页

作者： Zhao YUAN mohammad reza HESAMZADEH Department of Electric Power and Energy Systems KTH Royal Institute of Technology

Optimal power flow(OPF) is the fundamental mathematical model to optimize power system *** on conic relaxation, Taylor series expansion and McCormick envelope, we propose three convex OPF models to improve the performance of the second-order cone alternating current OPF(SOC-ACOPF) model. The underlying idea of the proposed SOC-ACOPF models is to drop assumptions of the original SOC-ACOPF model by convex relaxation and approximation methods.A heuristic algorithm to recover feasible ACOPF solution from the relaxed solution of the proposed SOC-ACOPF models is developed. The proposed SOC-ACOPF models are examined through IEEE case studies under various load scenarios and power network congestions. The quality of solutions from the proposed SOC-ACOPF models is evaluated using MATPOWER(local optimality) and LINDOGLOBAL(global optimality). We also compare numerically the proposed SOC-ACOPF models with other two convex ACOPF models in the *** numerical results show robust performance of the proposed SOCACOPF models and the feasible solution recovery algorithm.

关键词： Optimal power flow Conic relaxation McCormick envelope Taylor series expansion Feasible solution

Effect of fiber hybridization on energy absorption and synergy in concrete

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1338-1349页

作者： Ahmadreza RAMEZANI mohammad reza ESFAHANI Department of Civil Engineering Ferdowsi University of MashhadMashhad 91775-1111Iran

In the present study,steel and polypropylene(PP)fibers have been utilized with the intent of obtaining hybrid fiber-reinforced concrete(HFRC)with desirable mechanical *** attempt has been made to scrutinize the properties of HFRC with the main concentration being on energy absorption characteristics of concrete and the efficacy of fiber hybridization in producing ***,a total of 180 specimens,representing 20 different mixtures have been cast and evaluated through compressive,split tensile,and flexural *** relevant flexural toughness of the specimens was calculated using ASTM C1018,ASTM Cl 609,JSCE,and PCS methods,and the effectiveness of these methods was evaluated based on the experimental *** was observed that steel fibers are more effective in the improvement of flexural toughness in the presence ofPP ***,synergy associated with the combination of fibers at different stages of deflection of the beam specimens was observed and analyzed.

关键词： hybrid fiber-reinforced concrete synergy toughness steel fibers polypropylene fibers

An enhanced damage plasticity model for predicting the cyclic behavior of plain concrete under multiaxial loading conditions

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1531-1544页

作者： mohammad reza AZADI KAKAVAND Ertugrul TACIROGLU Unit of Strength of Materials and Structural Analysis Institute of Basic Sciences in Engineering SciencesUniversity of InnsbruckInnsbruck 6020Austria Department of Civil&Environmental Engineering University ofCaliforniaLos AngelesCA 90095USA

Some of the current concrete damage plasticity models in the literature employ a single damage variable for both the tension and compression regimes,while a few more advanced models employ two damage *** with a single variable have an inherent dificulty in accounting for the damage accrued due to tensile and compressive actions in appropriately different manners,and their mutual *** the current models that adopt two damage variables,the independence of these damage variables during cyclic loading results in the failure to capture the effects of tensile damage on the compressive behavior of concrete and *** study presents a cyclic model established by extending an existing monotonic constitutive *** model describes the cyclic behavior of concrete under multiaxial loading conditions and considers the influence of tensile/compressive damage on the compressive/tensile *** proposed model,dubbed the enhanced concrete damage plasticity model(ECDPM),is an extension of an existing model that combines the theories of classical plasticity and continuum damage *** most prior studies on models in the same category,the performance of the proposed ECDPM is evaluated using experimental data on concrete specimens at the material level obtained under cyclic multiaxial loading conditions including uniaxial tension and confined *** performance of the model is observed to be ***,the superiority of ECDPM over three previously proposed constitutive models is demonstrated through comparisons with the results of a uniaxial tension-compression test and a virtual test.

关键词： damage plasticity model plain concrete cyclic loading multiaxial loading conditions

Effect of an end plate on surface pressure distributions of two swept wings

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Chinese Journal of Aeronautics 2017年第5期30卷 1631-1643页

作者： mohammad reza SOLTANI Mehran MASDARI mohammad Rasoul TIRANDAZ Department of Aerospace Engineering Sharif University of Technology Tehran 19166Iran Faculty of New Sciences and Technologies University of Tehran Tehran Iran

A series of wind tunnel tests was conducted to examine how an end plate affects the pressure distributions of two wings with leading edge（LE） sweep angles of 23° and 40°. All the experiments were carried out at a midchord Reynolds number of 8×10～5, covering an angle of attack（AOA） range from -2° to 14°. Static pressure distribution measurements were acquired over the upper surfaces of the wings along three chordwise rows and one spanwise direction at the wing quarter-chord line. The results of the tests confirm that at a particular AOA, increasing the sweep angle causes a noticeable decrease in the upper-surface suction pressure. Furthermore, as the sweep angle increases, the development of a laminar separation bubble near the LEs of the wings takes place at higher AOAs. On the other hand, spanwise pressure measurements show that increasing the wing sweep angle results in forming a stronger vortex on the quarter-chord line which has lower sensitivity to AOA variation and remains substantially attached to the wing surface for higher AOAs than that can be achieved in the case of a lower sweep angle. In addition, data obtained indicate that installing an end plate further reinforces the spanwise flow over the wing surface, thus affecting the pressure distribution.

关键词： Chordwise Flow field Pressure distribution Swept wing Wind tunnel

Fusion of color and hallucinated depth features for enhanced multimodal deep learning-based damage segmentation

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 55-68页

作者： Tarutal Ghosh Mondal mohammad reza Jahanshahi Civil Architectural and Environmental EngineeringMissouri University of Science and TechnologyRollaMOUSA Lyles School of Civil Engineering Purdue UniversityWest LafayetteINUSA School of Electrical and Computer Engineering Purdue UniversityWest LafayetteINUSA

Recent advances in computer vision and deep learning have shown that the fusion of depth information can significantly enhance the performance of RGB-based damage detection and segmentation ***,alongside the advantages,depth-sensing also presents many practical *** instance,the depth sensors impose an additional payload burden on the robotic inspection platforms limiting the operation time and increasing the inspection ***,some lidar-based depth sensors have poor outdoor performance due to sunlight contamination during the *** this context,this study investigates the feasibility of abolishing depth-sensing at test time without compromising the segmentation *** autonomous damage segmentation framework is developed,based on recent advancements in vision-based multi-modal sensing such as modality hallucination(MH)and monocular depth estimation(MDE),which require depth data only during the model *** the time of deployment,depth data becomes expendable as it can be simulated from the corresponding RGB *** makes it possible to reap the benefits of depth fusion without any depth perception per *** study explored two different depth encoding techniques and three different fusion strategies in addition to a baseline RGB-based *** proposed approach is validated on computer-generated RGB-D data of reinforced concrete buildings subjected to seismic *** was observed that the surrogate techniques can increase the segmentation IoU by up to 20.1%with a negligible increase in the computation ***,this study is believed to make a positive contribution to enhancing the resilience of critical civil infrastructure.

关键词： multimodal data fusion depth sensing vision-based inspection UAV-assisted inspection damage segmentation post-disaster reconnaissance modality hallucination monocular depth estimation

Detection mechanism and classification of design principles of peroxidase mimic based colorimetric sensors: A brief overview

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1492-1503页

作者： Ali reza Hormozi Jangi mohammad reza Hormozi Jangi Saeed reza Hormozi Jangi Department of Chemistry College of SciencesShiraz UniversityShiraz 71454Iran

Synthesis and characterization of enzyme mimics with characteristic stability and high catalytic efficiency is an interesting field for ***,with the development of nanoscience and introducing of Fe3O4 magnetic nanoparticles as peroxidase mimics in 2007,various nanomaterials such as noble metals,metal oxides,and carbon materials were introduced as enzyme mimics(nanozymes).Various nanomaterials exhibit peroxidaselike activity,hence,most of the nanozymes are peroxidase *** the nanozyme based sensors were previously classified,the classifications have been focused on the type of nanozyme ***,the nanozyme based sensors were classified as peroxidase,hydrolase,and urease mimic-based ***,heretofore,these sensors are not classified based on the detection mechanism and principles of system *** aim of this review is the focus on the peroxidase mimic based colorimetric sensors as the most common nanozyme-based sensors and their classification based on principles of sensor design and review of the detection mechanism of the current mimic peroxidase based ***,some current challenges and future developments in this field are discussed.

关键词： Peroxidase mimic Nanozyme Enzyme-peroxidase mimic hybrids HP sensing pH sensing Enzyme co-embedded nanomaterials

Impact of Industrial Agglomeration on Productivity: Evidence from Iran’s Food Industry

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Chinese Geographical Science 2020年第2期30卷 309-323页

作者： Nastaran NAJKAR mohammad reza KOHANSAL mohammad GHORBANI Department of Agricultural Economics International Campus of Ferdowsi University of MashhadMashhad ***Iran Department of Agricultural Economics Ferdowsi University of MashhadMashhad ***Iran

This paper aims to examine the effect of agglomeration on firm level productivity in Iran’s food manufacturing by employing a firm level dataset during 1986–2015 among firms for four *** empirical results show that agglomeration in north districts are key factors in productivity *** this work,we apply a spatial Bayes model that uses hierarchical techniques during the three *** productivity clustering map is able to capture such patterns as the high productivity area that appears in the south,north districts of *** paper evaluates the effect of agglomeration on firm productivity in Iran’s food industries at district *** find that regional market potential is the strong predictor of productivity;moreover,industrial agglomeration has a productivity-augmenting impact.

关键词： Agglomeration productivity spatial Bayes hierarchical Iran