Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864714
Christian Thormann, A. Winkler
The paper investigates an additional application of RFID technology (Radio Frequency Identification) in combination with industrial robots. Besides identification and data storage in transponders, it is also possible to use RFID to localize objects. Some examples can be found in the field of mobile robotics. In this contribution, RFID technology is applied to robotic manipulators. In a final Industry 4.0 scenario, they may create a map of objects in the work cell in parallel to their main task, such as handling or finishing. Therefore, this paper considers the possibilities of RFID-based object localization with an industrial robot, which is equipped with an RFID antenna. First, the localization in two dimensions is investigated by the additional modification of transmission power. Thereafter, the spatial position of a single transponder is estimated. Finally, multiple transponders are localized. All algorithms proposed in this paper are successfully verified by practical experiments and some ideas for further work are presented.
{"title":"Localization of Workpieces by Robot Manipulators Using RFID Technology","authors":"Christian Thormann, A. Winkler","doi":"10.1109/MMAR.2019.8864714","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864714","url":null,"abstract":"The paper investigates an additional application of RFID technology (Radio Frequency Identification) in combination with industrial robots. Besides identification and data storage in transponders, it is also possible to use RFID to localize objects. Some examples can be found in the field of mobile robotics. In this contribution, RFID technology is applied to robotic manipulators. In a final Industry 4.0 scenario, they may create a map of objects in the work cell in parallel to their main task, such as handling or finishing. Therefore, this paper considers the possibilities of RFID-based object localization with an industrial robot, which is equipped with an RFID antenna. First, the localization in two dimensions is investigated by the additional modification of transmission power. Thereafter, the spatial position of a single transponder is estimated. Finally, multiple transponders are localized. All algorithms proposed in this paper are successfully verified by practical experiments and some ideas for further work are presented.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134559842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864621
W. Kowalczyk, K. Kozlowski
This paper presents control algorithm for formation of multiple non-holonomic mobile robots. It combines persistent excitation trajectory tracking algorithm and collision avoidance based on artificial potential functions. The robots avoid collision with each other and static obstacles existing in the task-space. Stability analysis of the closed-loop system based on Lyapunov-like function is presented. Effectiveness of the proposed method is illustrated by simulation results. They include also case of bounded wheel controls.
{"title":"Formation of Two-Wheeled Mobile Robots Moving in the Task Space with Static Obstacles - Numerical Verification for Bounded Controls","authors":"W. Kowalczyk, K. Kozlowski","doi":"10.1109/MMAR.2019.8864621","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864621","url":null,"abstract":"This paper presents control algorithm for formation of multiple non-holonomic mobile robots. It combines persistent excitation trajectory tracking algorithm and collision avoidance based on artificial potential functions. The robots avoid collision with each other and static obstacles existing in the task-space. Stability analysis of the closed-loop system based on Lyapunov-like function is presented. Effectiveness of the proposed method is illustrated by simulation results. They include also case of bounded wheel controls.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131420710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864664
Hossam T. Al-Fiky, M. Asfoor, M. Yacoub, A. M. Sharaf
In this decade, modern Battery Electric Vehicles (BEVs) had witnessed the intervention of in-wheel BLDC motors which led to improved overall efficiency due to the absence of both; the mechanical power train and the brushes. In the present work, a detailed parameterized model of a PM-BLDC motor is considered to estimate its torque-speed characteristics accurately. Three differential equations are simultaneously solved to estimate the motor characteristics. Additionally, an electric drive system is fully modeled including: Li-ion battery, six-step voltage inverters and Hall sensors in the presence of disturbance load torque. For the complete motor parameters to be fed to the model, experimental system identification is implemented. The steady-state response behavior of the motor is validated. In order to control the motor's rotational speed with enhanced transient response, a PID speed controller is implemented. The controlled BLDC motor model results include the speed, back EMF, motor torque and armature phase currents. The results show that, the proposed in-wheel PM-BLDC motor model could be reliably employed as a tool for BEVs modeling.
{"title":"Speed Control Modeling for In-Wheel Permanent Magnet Brushless DC Motors for Electric Vehicles","authors":"Hossam T. Al-Fiky, M. Asfoor, M. Yacoub, A. M. Sharaf","doi":"10.1109/MMAR.2019.8864664","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864664","url":null,"abstract":"In this decade, modern Battery Electric Vehicles (BEVs) had witnessed the intervention of in-wheel BLDC motors which led to improved overall efficiency due to the absence of both; the mechanical power train and the brushes. In the present work, a detailed parameterized model of a PM-BLDC motor is considered to estimate its torque-speed characteristics accurately. Three differential equations are simultaneously solved to estimate the motor characteristics. Additionally, an electric drive system is fully modeled including: Li-ion battery, six-step voltage inverters and Hall sensors in the presence of disturbance load torque. For the complete motor parameters to be fed to the model, experimental system identification is implemented. The steady-state response behavior of the motor is validated. In order to control the motor's rotational speed with enhanced transient response, a PID speed controller is implemented. The controlled BLDC motor model results include the speed, back EMF, motor torque and armature phase currents. The results show that, the proposed in-wheel PM-BLDC motor model could be reliably employed as a tool for BEVs modeling.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132243233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864710
Thomas Hansen, Maria A. B. Jørgensen, Van Roy Tran, Kasper Jessen, M. Soltani
This paper will focus on using system identification on experimental data for building a mathematical model for the platform of a floating offshore wind turbine and analyzing the behavior of the structure. The floating offshore wind turbine examined in this paper uses a scaled tension leg platform as its foundation and the wind turbine is a 1:35 scaled model of the 5 MW NREL offshore wind turbine. The mathematical model of the platform will describe the displacement of the TLP in surge when affected by an irregular wave series generated from a scaled Pierson-Moskowitz wave spectrum. To obtain such a mathematical model, an examination of the displacement of the platform due to the hydrodynamic loads will be conducted on the foundation of the floating offshore wind turbine. The height of the waves and the displacement of the floating offshore wind turbines will be measured by resistive wave gauges and OptiTrack cameras, respectively, at the offshore laboratory at Aalborg University Esbjerg. System identification is used on the data obtained from the experiments, to build multiple mathematical models with different model structures, in order to find the most appropriate model structure. It is concluded from the analysis of the different mathematical models, that the Autoregressive Moving Average and Extra input model structure is the most accurate model at describing the dynamics of the platform of a floating offshore wind turbine. The model is valid for a specific operating range of Pierson-Moskowitz waves generated with a wind speed corresponding to 2 meters per seconds.
{"title":"System Identification and model comparison of a Tension Leg Platform for Floating Offshore Wind Turbines","authors":"Thomas Hansen, Maria A. B. Jørgensen, Van Roy Tran, Kasper Jessen, M. Soltani","doi":"10.1109/MMAR.2019.8864710","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864710","url":null,"abstract":"This paper will focus on using system identification on experimental data for building a mathematical model for the platform of a floating offshore wind turbine and analyzing the behavior of the structure. The floating offshore wind turbine examined in this paper uses a scaled tension leg platform as its foundation and the wind turbine is a 1:35 scaled model of the 5 MW NREL offshore wind turbine. The mathematical model of the platform will describe the displacement of the TLP in surge when affected by an irregular wave series generated from a scaled Pierson-Moskowitz wave spectrum. To obtain such a mathematical model, an examination of the displacement of the platform due to the hydrodynamic loads will be conducted on the foundation of the floating offshore wind turbine. The height of the waves and the displacement of the floating offshore wind turbines will be measured by resistive wave gauges and OptiTrack cameras, respectively, at the offshore laboratory at Aalborg University Esbjerg. System identification is used on the data obtained from the experiments, to build multiple mathematical models with different model structures, in order to find the most appropriate model structure. It is concluded from the analysis of the different mathematical models, that the Autoregressive Moving Average and Extra input model structure is the most accurate model at describing the dynamics of the platform of a floating offshore wind turbine. The model is valid for a specific operating range of Pierson-Moskowitz waves generated with a wind speed corresponding to 2 meters per seconds.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132554655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864716
P. Domański, M. Lawrynczuk, Sebastian Golonka, B. Moszowski, Piotr Matyja
This paper is concerned with Control Performance Assessment (CPA) of an industrial nitric fertilizer production installation. As many as more than 200 single or cascaded loops based on the PID control algorithm are considered. Effectiveness of various control loop quality measures is compared: integral indexes, factors of different probabilistic density functions and persistence fractal measures are taken into account. Finally, the most informative ones are integrated into a single radar plot being the common platform for comparison. Analysis is accompanied with PID settings analysis showing further tuning directions. As each of the installation elements is in different status, the results enable to point out necessary steps for future plant improvements.
{"title":"Multi-criteria Loop Quality Assessment: A Large-Scale Industrial Case Study","authors":"P. Domański, M. Lawrynczuk, Sebastian Golonka, B. Moszowski, Piotr Matyja","doi":"10.1109/MMAR.2019.8864716","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864716","url":null,"abstract":"This paper is concerned with Control Performance Assessment (CPA) of an industrial nitric fertilizer production installation. As many as more than 200 single or cascaded loops based on the PID control algorithm are considered. Effectiveness of various control loop quality measures is compared: integral indexes, factors of different probabilistic density functions and persistence fractal measures are taken into account. Finally, the most informative ones are integrated into a single radar plot being the common platform for comparison. Analysis is accompanied with PID settings analysis showing further tuning directions. As each of the installation elements is in different status, the results enable to point out necessary steps for future plant improvements.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126776974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864658
P. T. Anh, A. Babiarz, A. Czornik, M. Niezabitowski, S. Siegmund
This paper discusses dynamic properties of discrete Volterra equations of convolution type. The asymptotic separation of solutions is studied. More precisely, a polynomial lower bound for the norm of differences between two different solutions of discrete Volterra equations of convolution type is presented. We apply this result to the theory of fractional difference equations.
{"title":"On asymptotic properties of discrete Volterra equations of convolution type","authors":"P. T. Anh, A. Babiarz, A. Czornik, M. Niezabitowski, S. Siegmund","doi":"10.1109/MMAR.2019.8864658","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864658","url":null,"abstract":"This paper discusses dynamic properties of discrete Volterra equations of convolution type. The asymptotic separation of solutions is studied. More precisely, a polynomial lower bound for the norm of differences between two different solutions of discrete Volterra equations of convolution type is presented. We apply this result to the theory of fractional difference equations.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129457266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864703
Jako Fritz, A. Xhonneux, D. Müller
This contribution introduces a new system for distributed model predictive control of energy systems. This system uses multiple agents where each agents optimizes a subsystem. A central instance coordinates the individual agents and takes care of feasibility of the combination of the single solutions. The advantages of this approach are increased maintainability and privacy for the individual agents, thus increasing applicability to real-world systems where often multiple parties are involved in a single energy system. Where adequate, the agents perform MPC to control their subsystems. The system and method can be chosen for each agent individually. In order to build this system a framework is developed as existing frameworks lack one or more required features for the overall system. A small example is presented together with first results.
{"title":"Development of an Agent-Based System for Decentralized Control of District Energy Systems","authors":"Jako Fritz, A. Xhonneux, D. Müller","doi":"10.1109/MMAR.2019.8864703","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864703","url":null,"abstract":"This contribution introduces a new system for distributed model predictive control of energy systems. This system uses multiple agents where each agents optimizes a subsystem. A central instance coordinates the individual agents and takes care of feasibility of the combination of the single solutions. The advantages of this approach are increased maintainability and privacy for the individual agents, thus increasing applicability to real-world systems where often multiple parties are involved in a single energy system. Where adequate, the agents perform MPC to control their subsystems. The system and method can be chosen for each agent individually. In order to build this system a framework is developed as existing frameworks lack one or more required features for the overall system. A small example is presented together with first results.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128638933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864704
D. Knyazkov, G. Kostin, A. Gavrikov, H. Aschemann, A. Rauh
In this paper, a test rig available at the University of Rostock is considered that consists of two co-axial aluminum cylinders heated by a Peltier element (PE) located in between them. The end faces of the cylinders that are not in contact with the PE are thermally insulated. For the assessment of control structures, an accurate finite element (FE) model for the complete system is derived including a detailed thermoelectric model for the PE. Given experimental data from the test rig, characteristic system parameters of the PE - the Seebeck coefficient and the Ohmic resistance - are identified. A comparison of the parametrized overall FE model with validation data shows that the simulation results are in good agreement with experimental data.
{"title":"FEM Modeling and Parameter Identification of Thermoelectrical Processes in Cylindrical Bodies","authors":"D. Knyazkov, G. Kostin, A. Gavrikov, H. Aschemann, A. Rauh","doi":"10.1109/MMAR.2019.8864704","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864704","url":null,"abstract":"In this paper, a test rig available at the University of Rostock is considered that consists of two co-axial aluminum cylinders heated by a Peltier element (PE) located in between them. The end faces of the cylinders that are not in contact with the PE are thermally insulated. For the assessment of control structures, an accurate finite element (FE) model for the complete system is derived including a detailed thermoelectric model for the PE. Given experimental data from the test rig, characteristic system parameters of the PE - the Seebeck coefficient and the Ohmic resistance - are identified. A comparison of the parametrized overall FE model with validation data shows that the simulation results are in good agreement with experimental data.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130595124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864622
Kamil Klimkowicz, Robert Maniarski, M. Patan
The paper discuss an effective approach to iterative learning control synthesis for a class of distributed parameter systems described by partial differential equations with biharmonic operator. The study is carried out based on the example of transverse displacements in a cantilever beam induced by the external loads. The sufficient conditions for the convergence of the proposed iterative control law are formulated. Also, the resulting control learning scheme supported by effective implementation based on the finite element method was investigated subject to the different configurations of actuator/sensor field.
{"title":"Iterative learning control of deflections in vibrating beam","authors":"Kamil Klimkowicz, Robert Maniarski, M. Patan","doi":"10.1109/MMAR.2019.8864622","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864622","url":null,"abstract":"The paper discuss an effective approach to iterative learning control synthesis for a class of distributed parameter systems described by partial differential equations with biharmonic operator. The study is carried out based on the example of transverse displacements in a cantilever beam induced by the external loads. The sufficient conditions for the convergence of the proposed iterative control law are formulated. Also, the resulting control learning scheme supported by effective implementation based on the finite element method was investigated subject to the different configurations of actuator/sensor field.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125587589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-01DOI: 10.1109/MMAR.2019.8864667
M. Bonini, Augusto Urru, W. Echelmeyer
In standardized sectors such as the automotive, the cost-benefit ratio of automation solutions is high as they contribute to increase capacity, decrease costs and improve product quality. In less standardized application fields, the contribution of automation to improvements in capacity, cost and quality blurs. The automation of complex and unstructured tasks requires sophisticated, expensive and low-performing systems, whose impact on product quality is oftentimes not directly perceived by customers. As a result, the full automation of process chains in the general manufacturing or the logistic sectors is often a sub-optimal solution. Taking the distance from the false idea that a process should be either fully automated, or fully manual, this paper presents a novel heuristic method for design of lean human-robot interaction, the Quality Interaction Function Deployment, with the objective of the “right level of automation”. Functions are divided among human and automated agents and several automation scenarios are created and evaluated with respect to their compliance to the requirements of all process' stakeholders. As a result, synergies among operators (manual tasks) and machines (automated tasks) are improved, thus reducing time-losses and increasing productivity.
{"title":"The Quality Interaction Function Deployment for lean Human-Robot Interaction","authors":"M. Bonini, Augusto Urru, W. Echelmeyer","doi":"10.1109/MMAR.2019.8864667","DOIUrl":"https://doi.org/10.1109/MMAR.2019.8864667","url":null,"abstract":"In standardized sectors such as the automotive, the cost-benefit ratio of automation solutions is high as they contribute to increase capacity, decrease costs and improve product quality. In less standardized application fields, the contribution of automation to improvements in capacity, cost and quality blurs. The automation of complex and unstructured tasks requires sophisticated, expensive and low-performing systems, whose impact on product quality is oftentimes not directly perceived by customers. As a result, the full automation of process chains in the general manufacturing or the logistic sectors is often a sub-optimal solution. Taking the distance from the false idea that a process should be either fully automated, or fully manual, this paper presents a novel heuristic method for design of lean human-robot interaction, the Quality Interaction Function Deployment, with the objective of the “right level of automation”. Functions are divided among human and automated agents and several automation scenarios are created and evaluated with respect to their compliance to the requirements of all process' stakeholders. As a result, synergies among operators (manual tasks) and machines (automated tasks) are improved, thus reducing time-losses and increasing productivity.","PeriodicalId":392498,"journal":{"name":"2019 24th International Conference on Methods and Models in Automation and Robotics (MMAR)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117100151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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