Pub Date : 2023-07-20DOI: 10.24425/acs.2021.138695
R. Almeida, E. Girejko, Luís Machado, A. Malinowska, Natália Martins
This paper studies an evacuation problem described by a leader-follower model with bounded confidence under predictive mechanisms. We design a control strategy in such a way that agents are guided by a leader, which follows the evacuation path. The proposed evacuation algorithm is based on Model Predictive Control (MPC) that uses the current and the past information of the system to predict future agents’ behaviors. It can be observed that, with MPC method, the leader-following consensus is obtained faster in comparison to the conventional optimal control technique. The effectiveness of the developed MPC evacuation algorithm with respect to different parameters and different time domains is illustrated by numerical examples.
{"title":"Evacuation by leader-follower model with bounded confidence and predictive mechanisms","authors":"R. Almeida, E. Girejko, Luís Machado, A. Malinowska, Natália Martins","doi":"10.24425/acs.2021.138695","DOIUrl":"https://doi.org/10.24425/acs.2021.138695","url":null,"abstract":"This paper studies an evacuation problem described by a leader-follower model with bounded confidence under predictive mechanisms. We design a control strategy in such a way that agents are guided by a leader, which follows the evacuation path. The proposed evacuation algorithm is based on Model Predictive Control (MPC) that uses the current and the past information of the system to predict future agents’ behaviors. It can be observed that, with MPC method, the leader-following consensus is obtained faster in comparison to the conventional optimal control technique. The effectiveness of the developed MPC evacuation algorithm with respect to different parameters and different time domains is illustrated by numerical examples.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83604897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2022.141719
Santosh Kumar, R. Devarapalli
In this paper, an automatic voltage regulator (AVR) embedded with fractional order PID (FOPID) is employed for the alternator terminal voltage control. A novel meta-heuristic technique, a modified version of grey wolf optimizer (mGWO) is proposed to design and optimize the FOPID AVR system. The parameters of FOPID, namely, proportional gain ( 𝐾 𝑃 ) , the integral gain ( 𝐾 𝐼 ) , the derivative gain ( 𝐾 𝐷 ) , 𝜆 and 𝜇 have been optimally tuned with the proposed mGWO technique using a novel fitness function. The initial values of the 𝐾 𝑃 , 𝐾 𝐼 , and 𝐾 𝐷 of the FOPID controller are obtained using Ziegler-Nichols (ZN) method, whereas the initial values of 𝜆 and 𝜇 have been chosen as arbitrary values.The proposed algorithm offers more benefits such as easy implementation, fast convergence characteristics, and excellent computational ability for the optimization of functions with more than three variables. Additionally, the hasty tuning of FOPID controller parameters gives a high-quality result, and the proposed controller also improves the robustness of the system during uncertainties in the parameters. The quality of the simulated result of the proposed controller has been validatedby other state-of-the-art techniques in the literature.
{"title":"Fractional order PI λD μ controller with optimal parameters using Modified Grey Wolf Optimizer for AVR system","authors":"Santosh Kumar, R. Devarapalli","doi":"10.24425/acs.2022.141719","DOIUrl":"https://doi.org/10.24425/acs.2022.141719","url":null,"abstract":"In this paper, an automatic voltage regulator (AVR) embedded with fractional order PID (FOPID) is employed for the alternator terminal voltage control. A novel meta-heuristic technique, a modified version of grey wolf optimizer (mGWO) is proposed to design and optimize the FOPID AVR system. The parameters of FOPID, namely, proportional gain ( 𝐾 𝑃 ) , the integral gain ( 𝐾 𝐼 ) , the derivative gain ( 𝐾 𝐷 ) , 𝜆 and 𝜇 have been optimally tuned with the proposed mGWO technique using a novel fitness function. The initial values of the 𝐾 𝑃 , 𝐾 𝐼 , and 𝐾 𝐷 of the FOPID controller are obtained using Ziegler-Nichols (ZN) method, whereas the initial values of 𝜆 and 𝜇 have been chosen as arbitrary values.The proposed algorithm offers more benefits such as easy implementation, fast convergence characteristics, and excellent computational ability for the optimization of functions with more than three variables. Additionally, the hasty tuning of FOPID controller parameters gives a high-quality result, and the proposed controller also improves the robustness of the system during uncertainties in the parameters. The quality of the simulated result of the proposed controller has been validatedby other state-of-the-art techniques in the literature.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89342791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/ACS.2018.124709
V. Kucheruk, I. Kurytnik, P. Kulakov, R. Lishchuk, Y. Moskvichova, A. Kulakova
The article presents the method and algorithm of automatic pointer measuring devices (voltmeter, manometer, metronomes etc.) indications determination in order to determine their dynamic characteristics with the help of web-camera and personal computer. The results of test-ing and experimental research of developed tool for determining the dynamic characteristics of pointer measuring devices are given. Using this method, the algorithm and the software developed, the process of determining the dynamic characteristics of the pointer measuring devices was automated. The time of recognition and calculation of one measured value for a dual-core processor and webcam with a resolution of 0.3 Mp averages 250–330 ms.
{"title":"Definition of dynamic characteristics of pointer measuring devices on the basis of automatic indications determination","authors":"V. Kucheruk, I. Kurytnik, P. Kulakov, R. Lishchuk, Y. Moskvichova, A. Kulakova","doi":"10.24425/ACS.2018.124709","DOIUrl":"https://doi.org/10.24425/ACS.2018.124709","url":null,"abstract":"The article presents the method and algorithm of automatic pointer measuring devices (voltmeter, manometer, metronomes etc.) indications determination in order to determine their dynamic characteristics with the help of web-camera and personal computer. The results of test-ing and experimental research of developed tool for determining the dynamic characteristics of pointer measuring devices are given. Using this method, the algorithm and the software developed, the process of determining the dynamic characteristics of the pointer measuring devices was automated. The time of recognition and calculation of one measured value for a dual-core processor and webcam with a resolution of 0.3 Mp averages 250–330 ms.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86468378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this article, an engineering/physical dynamic system including losses is analyzed in relation to the stability from an engineer’s/physicist’s point of view. Firstly, conditions for a Hamiltonian to be an energy function, time independent or not, is explained herein. To analyze stability of engineering system, Lyapunov-like energy function, called residual energy function is used. The residual function may contain, apart from external energies, negative losses as well. This function includes the sum of potential and kinetic energies, which are special forms and ready-made (weak) Lyapunov functions, and loss of energies (positive and/or negative) of a system described in different forms using tensorial variables. As the Lypunov function, residual energy function is defined as Hamiltonian energy function plus loss of energies and then associated weak and strong stability are proved through the first time-derivative of residual energy function. It is demonstrated how the stability analysis can be performed using the residual energy functions in different formulations and in generalized motion space when available. This novel approach is applied to RLC circuit, AC equivalent circuit of Gunn diode oscillator for autonomous, and a coupled (electromechanical) example for nonautonomous case. In the nonautonomous case, the stability criteria can not be proven for one type of formulation, however, it can be proven in the other type formulation.
{"title":"Stability analysis of engineering/physical dynamic systems using residual energy function","authors":"Cim Civelek","doi":"10.24425/123456","DOIUrl":"https://doi.org/10.24425/123456","url":null,"abstract":"In this article, an engineering/physical dynamic system including losses is analyzed in relation to the stability from an engineer’s/physicist’s point of view. Firstly, conditions for a Hamiltonian to be an energy function, time independent or not, is explained herein. To analyze stability of engineering system, Lyapunov-like energy function, called residual energy function is used. The residual function may contain, apart from external energies, negative losses as well. This function includes the sum of potential and kinetic energies, which are special forms and ready-made (weak) Lyapunov functions, and loss of energies (positive and/or negative) of a system described in different forms using tensorial variables. As the Lypunov function, residual energy function is defined as Hamiltonian energy function plus loss of energies and then associated weak and strong stability are proved through the first time-derivative of residual energy function. It is demonstrated how the stability analysis can be performed using the residual energy functions in different formulations and in generalized motion space when available. This novel approach is applied to RLC circuit, AC equivalent circuit of Gunn diode oscillator for autonomous, and a coupled (electromechanical) example for nonautonomous case. In the nonautonomous case, the stability criteria can not be proven for one type of formulation, however, it can be proven in the other type formulation.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89033933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2021.139734
L. Popescu, Ramona-Maria Dimitrov
A problem of optimization for production and storge costs is studied. The problem consists in manufacture of n types of products, with some given restrictions, so that the total production and storage costs are minimal. The mathematical model is built using the framework of driftless control affine systems. Controllability is studied using Lie geometric methods and the optimal solution is obtained with Pontryagin Maximum Principle. It is proved that the economical system is not controllable, in the sense that we can only produce a certain quantity of products. Finally, some numerical examples are given with graphical representation.
{"title":"Application of maximum principle to optimization of production and storage costs","authors":"L. Popescu, Ramona-Maria Dimitrov","doi":"10.24425/acs.2021.139734","DOIUrl":"https://doi.org/10.24425/acs.2021.139734","url":null,"abstract":"A problem of optimization for production and storge costs is studied. The problem consists in manufacture of n types of products, with some given restrictions, so that the total production and storage costs are minimal. The mathematical model is built using the framework of driftless control affine systems. Controllability is studied using Lie geometric methods and the optimal solution is obtained with Pontryagin Maximum Principle. It is proved that the economical system is not controllable, in the sense that we can only produce a certain quantity of products. Finally, some numerical examples are given with graphical representation.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77684191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2021.137424
T. Fajraoui, B. Ghanmi, Fehmi Mabrouk, F. Omri
a class of homogeneous fractional Systems, then we shall prove that local and global behaviors are the same. The uniform Mittag-Leffler stability of homogeneous fractional time-varying systems is studied. A numerical example is given to illustrate the efficiency of the obtained results.
{"title":"Mittag-Leffler stability analysis of a class of homogeneous fractional systems","authors":"T. Fajraoui, B. Ghanmi, Fehmi Mabrouk, F. Omri","doi":"10.24425/acs.2021.137424","DOIUrl":"https://doi.org/10.24425/acs.2021.137424","url":null,"abstract":"a class of homogeneous fractional Systems, then we shall prove that local and global behaviors are the same. The uniform Mittag-Leffler stability of homogeneous fractional time-varying systems is studied. A numerical example is given to illustrate the efficiency of the obtained results.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73035568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2021.137420
S. Kazhikenova
The article presents ε -approximation of hydrodynamics equations’ stationary model along with the proof of a theorem about existence of a hydrodynamics equations’ strongly generalized solution. It was proved by a theorem on the existence of uniqueness of the hydrodynamics equations’ temperature model’s solution, taking into account energy dissipation. There was implemented the Galerkin method to study the Navier–Stokes equations, which provides the study of the boundary value problems correctness for an incompressible viscous flow both numerically and analytically. Approximations of stationary and non-stationary models of the hydrodynamics equations were constructed by a system of Cauchy–Kovalevsky equations with a small parameter ε . There was developed an algorithm for numerical modelling of the Navier– Stokes equations by the finite difference method.
{"title":"The unique solvability of stationary and non-stationary incompressible melt models in the case of their linearization","authors":"S. Kazhikenova","doi":"10.24425/acs.2021.137420","DOIUrl":"https://doi.org/10.24425/acs.2021.137420","url":null,"abstract":"The article presents ε -approximation of hydrodynamics equations’ stationary model along with the proof of a theorem about existence of a hydrodynamics equations’ strongly generalized solution. It was proved by a theorem on the existence of uniqueness of the hydrodynamics equations’ temperature model’s solution, taking into account energy dissipation. There was implemented the Galerkin method to study the Navier–Stokes equations, which provides the study of the boundary value problems correctness for an incompressible viscous flow both numerically and analytically. Approximations of stationary and non-stationary models of the hydrodynamics equations were constructed by a system of Cauchy–Kovalevsky equations with a small parameter ε . There was developed an algorithm for numerical modelling of the Navier– Stokes equations by the finite difference method.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79301819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2019.131228
E. Jezierski, Piotr Łuczak, Pawel Smyczynski, D. Zarychta
The paper presents the possibilities of teaching a robot controller to perform operations of autonomous segregation of objects differing in features that can be identified using a vision system. Objects can be arranged freely on the robot scene also covered withothers. In the learning phase, a robot operator presents the segregation method by moving subsequent objects held in a human hand, e.g. a red object to container A, a green object to container B, etc. The robot system, after recognizing the idea of segregation that is being done using the vision system, continues this work in an autonomous way, until all identified objects will be removed from robotic scene. There are no restrictions on the dimensions, shapes and placement of containers collecting segregated objects. The developed algorithms were verified on a test bench equipped with two modern robots KUKA LBR iiwa 14 R820.
{"title":"Human–robot cooperation in sorting of randomly distributed objects","authors":"E. Jezierski, Piotr Łuczak, Pawel Smyczynski, D. Zarychta","doi":"10.24425/acs.2019.131228","DOIUrl":"https://doi.org/10.24425/acs.2019.131228","url":null,"abstract":"The paper presents the possibilities of teaching a robot controller to perform operations of autonomous segregation of objects differing in features that can be identified using a vision system. Objects can be arranged freely on the robot scene also covered withothers. In the learning phase, a robot operator presents the segregation method by moving subsequent objects held in a human hand, e.g. a red object to container A, a green object to container B, etc. The robot system, after recognizing the idea of segregation that is being done using the vision system, continues this work in an autonomous way, until all identified objects will be removed from robotic scene. There are no restrictions on the dimensions, shapes and placement of containers collecting segregated objects. The developed algorithms were verified on a test bench equipped with two modern robots KUKA LBR iiwa 14 R820.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77976687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2019.129380
T. Kaczorek
A dynamical system is called positive if its trajectory starting from any nonnegative initial state remains forever in the positive orthant for all nonnegative inputs. An overview of state of the art in positive theory is given in the monographs and papers [1, 2, 6, 11, 12]. Variety of models having positive behavior can be found in engineering, economics, social sciences, biology and medicine. The stability of linear and nonlinear standard and positive fractional systems has been addressed in [3–6, 8, 15, 16, 20–23]. The stabilization of positive descriptor fractional systems has been investigated in [10, 11, 20, 21]. The superstable linear systems have been addressed in [17, 18]. Positive linear systems with different fractional orders have been introduced in [14, 13] and their stability has been analyzed in [3, 20]. The absolute stability of a class of positive nonlinear systems has been investigated in [7]. In this paper the positivity and absolute stability of a class of nonlinear continuous-time and discrete-time systems with nonpositive linear parts will be addressed. The paper is organized as follows. In section 2 some preliminaries concerning positivity and stability of linear systems are recalled. The positivity and absolute stability of positive continuous-time nonlinear systems with nonpositive linear
{"title":"Absolute stability of a class of nonlinear systems with nonpositive linear parts","authors":"T. Kaczorek","doi":"10.24425/acs.2019.129380","DOIUrl":"https://doi.org/10.24425/acs.2019.129380","url":null,"abstract":"A dynamical system is called positive if its trajectory starting from any nonnegative initial state remains forever in the positive orthant for all nonnegative inputs. An overview of state of the art in positive theory is given in the monographs and papers [1, 2, 6, 11, 12]. Variety of models having positive behavior can be found in engineering, economics, social sciences, biology and medicine. The stability of linear and nonlinear standard and positive fractional systems has been addressed in [3–6, 8, 15, 16, 20–23]. The stabilization of positive descriptor fractional systems has been investigated in [10, 11, 20, 21]. The superstable linear systems have been addressed in [17, 18]. Positive linear systems with different fractional orders have been introduced in [14, 13] and their stability has been analyzed in [3, 20]. The absolute stability of a class of positive nonlinear systems has been investigated in [7]. In this paper the positivity and absolute stability of a class of nonlinear continuous-time and discrete-time systems with nonpositive linear parts will be addressed. The paper is organized as follows. In section 2 some preliminaries concerning positivity and stability of linear systems are recalled. The positivity and absolute stability of positive continuous-time nonlinear systems with nonpositive linear","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77239575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-20DOI: 10.24425/acs.2019.129379
N. H. Taieb, Hammami, F. Delmotte
An important application of state estimation is feedback control: an estimate of the state (typically the mean estimate) is used as input to a state-feedback controller. This scheme is known as observer based control, and it is a common way of designing an output-feedback controller (i.e. a controller that does not have access to perfect state measurements). In this paper, under the fact that both the estimator dynamics and the state feedback dynamics are stable we propose a separation principle for Takagi-Sugeno fuzzy control systems with Lipschitz nonlinearities. The considered nonlinearities are Lipschitz or meets an integrability condition which have no influence on the LMI to prove the stability of the associated closed-loop system. Furthermore, we give an example to ullistrate the applicability of the main result.
{"title":"A separation principle for Takagi-Sugeno control fuzzy systems","authors":"N. H. Taieb, Hammami, F. Delmotte","doi":"10.24425/acs.2019.129379","DOIUrl":"https://doi.org/10.24425/acs.2019.129379","url":null,"abstract":"An important application of state estimation is feedback control: an estimate of the state (typically the mean estimate) is used as input to a state-feedback controller. This scheme is known as observer based control, and it is a common way of designing an output-feedback controller (i.e. a controller that does not have access to perfect state measurements). In this paper, under the fact that both the estimator dynamics and the state feedback dynamics are stable we propose a separation principle for Takagi-Sugeno fuzzy control systems with Lipschitz nonlinearities. The considered nonlinearities are Lipschitz or meets an integrability condition which have no influence on the LMI to prove the stability of the associated closed-loop system. Furthermore, we give an example to ullistrate the applicability of the main result.","PeriodicalId":48654,"journal":{"name":"Archives of Control Sciences","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77258868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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