Predicting the mechanical behaviors of structure and perceiving the anomalies in advance are essential to ensuring the safe operation of infrastructures in the long run.In addition to the incomplete consideration of i...Predicting the mechanical behaviors of structure and perceiving the anomalies in advance are essential to ensuring the safe operation of infrastructures in the long run.In addition to the incomplete consideration of influencing factors,the prediction time scale of existing studies is rough.Therefore,this study focuses on the development of a real-time prediction model by coupling the spatio-temporal correlation with external load through autoencoder network(ATENet)based on structural health monitoring(SHM)data.An autoencoder mechanism is performed to acquire the high-level representation of raw monitoring data at different spatial positions,and the recurrent neural network is applied to understanding the temporal correlation from the time series.Then,the obtained temporal-spatial information is coupled with dynamic loads through a fully connected layer to predict structural performance in next 12 h.As a case study,the proposed model is formulated on the SHM data collected from a representative underwater shield tunnel.The robustness study is carried out to verify the reliability and the prediction capability of the proposed model.Finally,the ATENet model is compared with some typical models,and the results indicate that it has the best performance.ATENet model is of great value to predict the realtime evolution trend of tunnel structure.展开更多
In the purpose of defining typical urban water management challenges in coastal lowlands in the context of global climate change, a comparative study was conducted between two coastal new towns respectively located in...In the purpose of defining typical urban water management challenges in coastal lowlands in the context of global climate change, a comparative study was conducted between two coastal new towns respectively located in the Netherlands and Northern China. Comparative method is applied to define main functioning patterns of urban water systems in the two cases, then computer simulations were used to furthercompare drainage capacity in order to reveal the trends of urban water management. Major resulthas shown that Almere in the Netherlands generally more advanced in urban water management asmultiple functioning patterns are available.Strong dykes maintain competence for land subsidence and sea level rise. Open water system decreases local runoff and increaseswater retention level. Systematic control ofsluicesand locks which serve for shipping and waterfront landscaping are simultaneously isolating contaminants from outer water body. Tianjin Eco-city in China has shown both strengths and weaknesses. It takes large amount of reclaimed water as main landscaping water source, which adapts to local water pollution and shortage while requires highly centralized facilities. Large water body is reserved and huge scale underground drainage system built, but it is still vulnerable to heavy storms due to the lack of efficient surface water drainage system. Coastal line control does not adequately prevent from increasing storm surge risks in the future. SWMMsimulations have supported the viewpoint ofdistributed surface water with a higher efficiency for storm drainage. Meanwhile, surface water system returns more added values to urban development. The study is corresponding well with the theory of water sensitive city. As a conclusion, urban water system should always incorporate methods to achieve higher system resilience based on multiple functioning patterns.展开更多
Strontium titanate(STO)is an n-type oxide thermoelectric material,which has shown great prospects in recent years.The doping of La and Nb into STO can improve its power factor,whereas its thermal conductivity is sti...Strontium titanate(STO)is an n-type oxide thermoelectric material,which has shown great prospects in recent years.The doping of La and Nb into STO can improve its power factor,whereas its thermal conductivity is still very high.Thus,in order to obtain a high thermoelectric figure-of-merit z T,it is very important to reduce its thermal conductivity.In this paper,using a combination of a hydrothermal method and a high-efficiency sintering method,we succeed in preparing a composite of pure STO and La Nb-doped STO,which simultaneously realizes lower thermal conductivity and higherSeebeck coefficient,therefore,the thermoelectric properties of STO are significantly improved.In the SrTiO3/La Nb–SrTiO3 bulk samples,the lowest thermal conductivity is 2.57 W·m^-1·K^-1 and the highest z T is 0.35 at 1000 K for the STO/La(10)Nb(20)–STO sample.展开更多
The rainfall induced landslides and debris flows are the major disasters in China, as well in Europe, South America, Japan and Australia. This paper proposes a new type of joint probability prediction model—Double La...The rainfall induced landslides and debris flows are the major disasters in China, as well in Europe, South America, Japan and Australia. This paper proposes a new type of joint probability prediction model—Double Layer Nested Multivariate Compound Extreme Value Distribution (DLNMCEVD) to predict landslides and debris flows triggered by rainfall. The outer layer of DLNMCEVD is predicting the joint probabilities of different combinations for rainfall characteristics, air temperature and humidity, which should be considered as external load factors with geological and geotechnical characteristics as resistance factors for reliability analysis of slope stability in the inner layer of model. For the reliability and consequence analysis of rainfall-induced slope failure, the Global Uncertainty Analysis and Global Sensitivity Analysis (GUA & GSA) should be taken into account for input-output iterations. Finally, based on the statistics prediction by DLNMCEVD, the geological hazards prevention alarm and regionalization can be provided in this paper.展开更多
The World Meteorological Organization estimates that about 90 percent of all natural disasters is extreme meteorological hazards like typhoon/hurricane and tropical cyclone triggered disasters. With the increasing ten...The World Meteorological Organization estimates that about 90 percent of all natural disasters is extreme meteorological hazards like typhoon/hurricane and tropical cyclone triggered disasters. With the increasing tendency of natural hazards, the typhoon induced surge, wave, precipitation, flood and wind as extreme external loads menacing Nuclear Power Plants (NPP) in coastal and inland provinces of China. For all of the planned, designed and constructed NPP in China the National Nuclear Safety Administration of China and IAEA recommended Probable Maximum Hurricane/ Typhoon/(PMH/T), Probable Maximum Storm Surge (PMSS), Probable Maximum Flood (PMF), Design Basis Flood (DBF) as safety regulations recommended for NPP defense infrastructures. This paper discusses the joint probability analysis of simultaneous occurrence typhoon induced extreme external hazards and compared with IAEA 2003-2011 recommended safety regulations for some NPP along China coast to make safety assessment based on the “As Low As Reasonable Practice” (ALARP) principle.展开更多
In the emerging Industrial Internet of Things(IIoT),authentication problems have become an urgent issue for massive resource-constrained devices because traditional costly security mechanisms are not suitable for them...In the emerging Industrial Internet of Things(IIoT),authentication problems have become an urgent issue for massive resource-constrained devices because traditional costly security mechanisms are not suitable for them.The security protocol designed for resource-constrained systems should not only be secure but also efficient in terms of usage of energy,storage,and processing.Although recently many lightweight schemes have been proposed,to the best of our knowledge,they are unable to address the problem of privacy preservation with the resistance of Denial of Service(DoS)attacks in a practical way.In this paper,we propose a lightweight authentication protocol based on the Physically Unclonable Function(PUF)to overcome the limitations of existing schemes.The protocol provides an ingenious authentication and synchronization mechanism to solve the contradictions amount forward secrecy,DoS attacks,and resource-constrained.The performance analysis and comparison show that the proposed scheme can better improve the authentication security and efficiency for resource-constrained systems in IIoT.展开更多
Magnetic susceptibility,specific heat,and neutron powder diffraction measurements have been performed on polycrystalline Li_(2)Co(WO_4)_(2)samples.Under zero magnetic field,two successive magnetic transitions at T_(N1...Magnetic susceptibility,specific heat,and neutron powder diffraction measurements have been performed on polycrystalline Li_(2)Co(WO_4)_(2)samples.Under zero magnetic field,two successive magnetic transitions at T_(N1)~9.4 K and T_(N2)~7.4 K are observed.The magnetic ordering temperatures gradually decrease as the magnetic field increases.Neutron diffraction reveals that Li_(2)Co(WO_4)_(2)enters an incommensurate magnetic state with a temperature dependent k between T_(N1)and T_(N2).The magnetic propagation vector locks-in to a commensurate value k=(1/2,1/4,1/4)below T_(N2).The antiferromagnetic structure is refined at 1.7 K with Co2+magnetic moment 2.8(1),μ_B,consistent with our first-principles calculations.展开更多
Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The o...Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.展开更多
The Xiangshan mafic-ultramafic complex is one of the major Early Permian maficultramafic intrusions in eastern Tianshan (Xinjiang, NW China), and consists of two major intrusive phases. The first intrusive phase is ...The Xiangshan mafic-ultramafic complex is one of the major Early Permian maficultramafic intrusions in eastern Tianshan (Xinjiang, NW China), and consists of two major intrusive phases. The first intrusive phase is mainly gabbroic rocks hosting ilmenite mineralization, while the second intrusive phase is mainly lherzoilite associated with Ni-Cu sulfide mineralization. The Xiangshan ilmenite orebodies hosted in the Fe-Ti oxide-bearing gabbro occur along the contact between hornblende gabbros and leucogabbros. The hornblende gabbros and Fe-Ti oxide rich gabbros at Xiangshan are newly dated to be Early Permian (280.1 and 279.2 Ma, respectively). Major and trace element compositions of zircons and whole rocks from Xiangshan hornblende gabbro and Fe-Ti oxide gabbro have been measured by in situ excimer laser ablation ICP-MS. Zircon Ce^4+/Ce^3+ ratios based on lattice-strain model and Ti-in-zircon temperatures of hornblende gabbro and Fe-Ti oxide gabbro of the Xiangshan complex are calculated to evaluate the physicochemical variations during the ilmenite mineralization. Whole-rock geochemistry and zircon trace element geochemistry suggest that Fe-Ti oxide gabbros were formed from a basaltic parent magma which had undergone a transfromation from being H2O-rich to H2O-poor. During the magmatic evolution, primitive, HEO-poor basaltic melts may have been replenished into the system, increasing its solidus temperature and decreasing its oxygen fugacity and H2O contents. This may have supperessed the Ti-rich poikilitic hornblende fractionation and promoted the plagioclase fractionation, which consequently concentrated the ore-forming components in the residual melts and generated the ilmenite mineralization.展开更多
Spatially distributed systems (SDSs) are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model...Spatially distributed systems (SDSs) are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model is required. In this paper, a time/space separation based 3D fuzzy modeling approach is proposed for unknown nonlinear SDSs using input-output data measurement. The main characteristics of this approach is that time/space separation and time/space reconstruction are fused into a novel 3D fuzzy system. The modeling methodology includes two stages. The first stage is 3D fuzzy structure modeling which is based on Mamdani fuzzy rules. The consequent sets of 3D fuzzy rules consist of spatial basis functions estimated by Karhunen-Love decomposition. The antecedent sets of 3D fuzzy rules are used to construct temporal coefficients. Going through 3D fuzzy rule inference, each rule realizes time/space synthesis. The second stage is parameter identification of 3D fuzzy system using particle swarm optimization algorithm. After an operation of defuzzification, the output of the 3D fuzzy system can reconstruct the spatio-temporal dynamics of the system. The model is suitable for the prediction and control design of the SDS since it is of low-dimension and simple nonlinear structure. The simulation and experiment are presented to show the effectiveness of the proposed modeling approach.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.51991392)Key Deployment Projects of Chinese Academy of Sciences(Grant No.ZDRW-ZS-2021-3-3)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0904).
文摘Predicting the mechanical behaviors of structure and perceiving the anomalies in advance are essential to ensuring the safe operation of infrastructures in the long run.In addition to the incomplete consideration of influencing factors,the prediction time scale of existing studies is rough.Therefore,this study focuses on the development of a real-time prediction model by coupling the spatio-temporal correlation with external load through autoencoder network(ATENet)based on structural health monitoring(SHM)data.An autoencoder mechanism is performed to acquire the high-level representation of raw monitoring data at different spatial positions,and the recurrent neural network is applied to understanding the temporal correlation from the time series.Then,the obtained temporal-spatial information is coupled with dynamic loads through a fully connected layer to predict structural performance in next 12 h.As a case study,the proposed model is formulated on the SHM data collected from a representative underwater shield tunnel.The robustness study is carried out to verify the reliability and the prediction capability of the proposed model.Finally,the ATENet model is compared with some typical models,and the results indicate that it has the best performance.ATENet model is of great value to predict the realtime evolution trend of tunnel structure.
文摘In the purpose of defining typical urban water management challenges in coastal lowlands in the context of global climate change, a comparative study was conducted between two coastal new towns respectively located in the Netherlands and Northern China. Comparative method is applied to define main functioning patterns of urban water systems in the two cases, then computer simulations were used to furthercompare drainage capacity in order to reveal the trends of urban water management. Major resulthas shown that Almere in the Netherlands generally more advanced in urban water management asmultiple functioning patterns are available.Strong dykes maintain competence for land subsidence and sea level rise. Open water system decreases local runoff and increaseswater retention level. Systematic control ofsluicesand locks which serve for shipping and waterfront landscaping are simultaneously isolating contaminants from outer water body. Tianjin Eco-city in China has shown both strengths and weaknesses. It takes large amount of reclaimed water as main landscaping water source, which adapts to local water pollution and shortage while requires highly centralized facilities. Large water body is reserved and huge scale underground drainage system built, but it is still vulnerable to heavy storms due to the lack of efficient surface water drainage system. Coastal line control does not adequately prevent from increasing storm surge risks in the future. SWMMsimulations have supported the viewpoint ofdistributed surface water with a higher efficiency for storm drainage. Meanwhile, surface water system returns more added values to urban development. The study is corresponding well with the theory of water sensitive city. As a conclusion, urban water system should always incorporate methods to achieve higher system resilience based on multiple functioning patterns.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61751404,51702168,and 51665042)the Fund from the State Key Laboratory of New Ceramic and Fine Processing(Tsinghua University),China(Grant No.KF201608)+1 种基金the Fund from the Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology,China(Grant No.151004-K)the Natural Science Foundation of Inner Mongolia Autonomous Region,China(Grant Nos.2016BS0507 and 2015MS0509)
文摘Strontium titanate(STO)is an n-type oxide thermoelectric material,which has shown great prospects in recent years.The doping of La and Nb into STO can improve its power factor,whereas its thermal conductivity is still very high.Thus,in order to obtain a high thermoelectric figure-of-merit z T,it is very important to reduce its thermal conductivity.In this paper,using a combination of a hydrothermal method and a high-efficiency sintering method,we succeed in preparing a composite of pure STO and La Nb-doped STO,which simultaneously realizes lower thermal conductivity and higherSeebeck coefficient,therefore,the thermoelectric properties of STO are significantly improved.In the SrTiO3/La Nb–SrTiO3 bulk samples,the lowest thermal conductivity is 2.57 W·m^-1·K^-1 and the highest z T is 0.35 at 1000 K for the STO/La(10)Nb(20)–STO sample.
文摘The rainfall induced landslides and debris flows are the major disasters in China, as well in Europe, South America, Japan and Australia. This paper proposes a new type of joint probability prediction model—Double Layer Nested Multivariate Compound Extreme Value Distribution (DLNMCEVD) to predict landslides and debris flows triggered by rainfall. The outer layer of DLNMCEVD is predicting the joint probabilities of different combinations for rainfall characteristics, air temperature and humidity, which should be considered as external load factors with geological and geotechnical characteristics as resistance factors for reliability analysis of slope stability in the inner layer of model. For the reliability and consequence analysis of rainfall-induced slope failure, the Global Uncertainty Analysis and Global Sensitivity Analysis (GUA & GSA) should be taken into account for input-output iterations. Finally, based on the statistics prediction by DLNMCEVD, the geological hazards prevention alarm and regionalization can be provided in this paper.
文摘The World Meteorological Organization estimates that about 90 percent of all natural disasters is extreme meteorological hazards like typhoon/hurricane and tropical cyclone triggered disasters. With the increasing tendency of natural hazards, the typhoon induced surge, wave, precipitation, flood and wind as extreme external loads menacing Nuclear Power Plants (NPP) in coastal and inland provinces of China. For all of the planned, designed and constructed NPP in China the National Nuclear Safety Administration of China and IAEA recommended Probable Maximum Hurricane/ Typhoon/(PMH/T), Probable Maximum Storm Surge (PMSS), Probable Maximum Flood (PMF), Design Basis Flood (DBF) as safety regulations recommended for NPP defense infrastructures. This paper discusses the joint probability analysis of simultaneous occurrence typhoon induced extreme external hazards and compared with IAEA 2003-2011 recommended safety regulations for some NPP along China coast to make safety assessment based on the “As Low As Reasonable Practice” (ALARP) principle.
基金This work was supported by China Postdoctoral Science Foundation under Grant Nos.2020M681959 and 2020TQ0291in part by the national key R&D project under Grant No.2018YFB2100401in part by the National Key Research and Development Project No.2018YFB2100400.
文摘In the emerging Industrial Internet of Things(IIoT),authentication problems have become an urgent issue for massive resource-constrained devices because traditional costly security mechanisms are not suitable for them.The security protocol designed for resource-constrained systems should not only be secure but also efficient in terms of usage of energy,storage,and processing.Although recently many lightweight schemes have been proposed,to the best of our knowledge,they are unable to address the problem of privacy preservation with the resistance of Denial of Service(DoS)attacks in a practical way.In this paper,we propose a lightweight authentication protocol based on the Physically Unclonable Function(PUF)to overcome the limitations of existing schemes.The protocol provides an ingenious authentication and synchronization mechanism to solve the contradictions amount forward secrecy,DoS attacks,and resource-constrained.The performance analysis and comparison show that the proposed scheme can better improve the authentication security and efficiency for resource-constrained systems in IIoT.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11834002,12074111,and 11704109)the National Key R&D Project of China(Grant No.2016YFA0300101)。
文摘Magnetic susceptibility,specific heat,and neutron powder diffraction measurements have been performed on polycrystalline Li_(2)Co(WO_4)_(2)samples.Under zero magnetic field,two successive magnetic transitions at T_(N1)~9.4 K and T_(N2)~7.4 K are observed.The magnetic ordering temperatures gradually decrease as the magnetic field increases.Neutron diffraction reveals that Li_(2)Co(WO_4)_(2)enters an incommensurate magnetic state with a temperature dependent k between T_(N1)and T_(N2).The magnetic propagation vector locks-in to a commensurate value k=(1/2,1/4,1/4)below T_(N2).The antiferromagnetic structure is refined at 1.7 K with Co2+magnetic moment 2.8(1),μ_B,consistent with our first-principles calculations.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFB100140)National Natural Science Foundation of China(Grant No.51975136)+4 种基金Natural Science Foundation of Guangdong Province(Grant No.2023A1515011723)Industry-University-research Collaborative Innovation Base of Ministry of Education(Grant No.230703950183536,220903950010408)Special Research Projects in the Key Fields of Guangdong Higher Educational Universities(Grant No.2023ZDZX3016,2019KZDZX1009)Tertiary Education Scientific research project of Guangzhou Municipal Education Bureau(Grant No.202235139)Guangzhou University Research Project(Grant No.YJ2023034,YJ2021002).
文摘Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.
基金financially supported by the National Natural Science Foundation of China(No.41372102)the National Basic Research Program of China(No.2014CB440803)the China Geological Survey(No.DD20160071)
文摘The Xiangshan mafic-ultramafic complex is one of the major Early Permian maficultramafic intrusions in eastern Tianshan (Xinjiang, NW China), and consists of two major intrusive phases. The first intrusive phase is mainly gabbroic rocks hosting ilmenite mineralization, while the second intrusive phase is mainly lherzoilite associated with Ni-Cu sulfide mineralization. The Xiangshan ilmenite orebodies hosted in the Fe-Ti oxide-bearing gabbro occur along the contact between hornblende gabbros and leucogabbros. The hornblende gabbros and Fe-Ti oxide rich gabbros at Xiangshan are newly dated to be Early Permian (280.1 and 279.2 Ma, respectively). Major and trace element compositions of zircons and whole rocks from Xiangshan hornblende gabbro and Fe-Ti oxide gabbro have been measured by in situ excimer laser ablation ICP-MS. Zircon Ce^4+/Ce^3+ ratios based on lattice-strain model and Ti-in-zircon temperatures of hornblende gabbro and Fe-Ti oxide gabbro of the Xiangshan complex are calculated to evaluate the physicochemical variations during the ilmenite mineralization. Whole-rock geochemistry and zircon trace element geochemistry suggest that Fe-Ti oxide gabbros were formed from a basaltic parent magma which had undergone a transfromation from being H2O-rich to H2O-poor. During the magmatic evolution, primitive, HEO-poor basaltic melts may have been replenished into the system, increasing its solidus temperature and decreasing its oxygen fugacity and H2O contents. This may have supperessed the Ti-rich poikilitic hornblende fractionation and promoted the plagioclase fractionation, which consequently concentrated the ore-forming components in the residual melts and generated the ilmenite mineralization.
基金supported by National Science Foundation of China(Nos.61273182,31570998,51375293 and 61374112)
文摘Spatially distributed systems (SDSs) are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model is required. In this paper, a time/space separation based 3D fuzzy modeling approach is proposed for unknown nonlinear SDSs using input-output data measurement. The main characteristics of this approach is that time/space separation and time/space reconstruction are fused into a novel 3D fuzzy system. The modeling methodology includes two stages. The first stage is 3D fuzzy structure modeling which is based on Mamdani fuzzy rules. The consequent sets of 3D fuzzy rules consist of spatial basis functions estimated by Karhunen-Love decomposition. The antecedent sets of 3D fuzzy rules are used to construct temporal coefficients. Going through 3D fuzzy rule inference, each rule realizes time/space synthesis. The second stage is parameter identification of 3D fuzzy system using particle swarm optimization algorithm. After an operation of defuzzification, the output of the 3D fuzzy system can reconstruct the spatio-temporal dynamics of the system. The model is suitable for the prediction and control design of the SDS since it is of low-dimension and simple nonlinear structure. The simulation and experiment are presented to show the effectiveness of the proposed modeling approach.