Pub Date : 1999-07-12DOI: 10.1109/ISIE.1999.801751
L. Ribickis, I. Galkin
In this paper, several types of direct frequency converters are described and compared. Mathematical models and results of simulation are presented. The first mentioned type of direct frequency converter is a three-to-single-phase double-zone converter. It is based on two series connected controlled voltage sources and can generate 49 possible output voltages. Different types of control can be used in such a converter; for example amplitude phase synthesis or pulse-width modulation. In the article, a three-phase to three-phase matrix converter is also described. Details of the pulse-width modulation and space-vector modulation schemes in such a converter are discussed. Implementation of the multi-level principle in the matrix converter is briefly analyzed. In the final part of the paper, a comparison of the above-mentioned converters is performed.
{"title":"Direct frequency converters for induction motor drives","authors":"L. Ribickis, I. Galkin","doi":"10.1109/ISIE.1999.801751","DOIUrl":"https://doi.org/10.1109/ISIE.1999.801751","url":null,"abstract":"In this paper, several types of direct frequency converters are described and compared. Mathematical models and results of simulation are presented. The first mentioned type of direct frequency converter is a three-to-single-phase double-zone converter. It is based on two series connected controlled voltage sources and can generate 49 possible output voltages. Different types of control can be used in such a converter; for example amplitude phase synthesis or pulse-width modulation. In the article, a three-phase to three-phase matrix converter is also described. Details of the pulse-width modulation and space-vector modulation schemes in such a converter are discussed. Implementation of the multi-level principle in the matrix converter is briefly analyzed. In the final part of the paper, a comparison of the above-mentioned converters is performed.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126031823","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 : 1999-07-12DOI: 10.1109/ISIE.1999.798738
T. Szalay, F. Alpek
The paper presents a realized automated quality assurance system for the final assembly of a magnetic valve. The realization project joined to an international research project sponsored by the European Union however the quality assurance was not in the frame of that project. The system includes: (1) the supervision of the assembly cell and operations; (2) the functional test of the assembled valve; and (3) the automatic documentation and part following system. For realizing the aforementioned three components the original concept was worked out, the necessary design and plan were completed, the hardware and sensors were produced or installed, and the software was programmed. In the realization we had to consider the previously realized assembly cell, some economical constraints and the restrictions of the quality standard. The realized system has a close connection with the actual assembly process but the concept and the solution of the components can be applied generally after some not significant modification.
{"title":"Realization of the quality assurance for robotized assembly cell","authors":"T. Szalay, F. Alpek","doi":"10.1109/ISIE.1999.798738","DOIUrl":"https://doi.org/10.1109/ISIE.1999.798738","url":null,"abstract":"The paper presents a realized automated quality assurance system for the final assembly of a magnetic valve. The realization project joined to an international research project sponsored by the European Union however the quality assurance was not in the frame of that project. The system includes: (1) the supervision of the assembly cell and operations; (2) the functional test of the assembled valve; and (3) the automatic documentation and part following system. For realizing the aforementioned three components the original concept was worked out, the necessary design and plan were completed, the hardware and sensors were produced or installed, and the software was programmed. In the realization we had to consider the previously realized assembly cell, some economical constraints and the restrictions of the quality standard. The realized system has a close connection with the actual assembly process but the concept and the solution of the components can be applied generally after some not significant modification.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"285 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120966504","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 : 1999-07-12DOI: 10.1109/ISIE.1999.796786
H. Hur, J.M. Lee, Suk Lee, M.H. Lee
A predictive controller is designed based upon stochastic methods to compensate the time-delay on a system that inherently has time-delay caused by the spatial separation between controllers and actuators. The predictive controller estimates current outputs using a linear prediction function and a probability function in terms of previous outputs, and minimizes the malicious phenomena caused by time-delay in the precise control systems. To demonstrate effectiveness of this control methodology, this algorithm is applied to the control of a remote operated DC servomotor. The experimental results show that this predictive controller is superior to the conventional PID controller in terms of convergence characteristics, and also show that this controller expands the maximum allowable time-delay for a system. Since the proposed predictor does not require a specific model for the plant-it requires only stochastic information on the outputs-, it can be applied to the control of general nonlinear systems.
{"title":"Compensation of time delay using a predictive controller","authors":"H. Hur, J.M. Lee, Suk Lee, M.H. Lee","doi":"10.1109/ISIE.1999.796786","DOIUrl":"https://doi.org/10.1109/ISIE.1999.796786","url":null,"abstract":"A predictive controller is designed based upon stochastic methods to compensate the time-delay on a system that inherently has time-delay caused by the spatial separation between controllers and actuators. The predictive controller estimates current outputs using a linear prediction function and a probability function in terms of previous outputs, and minimizes the malicious phenomena caused by time-delay in the precise control systems. To demonstrate effectiveness of this control methodology, this algorithm is applied to the control of a remote operated DC servomotor. The experimental results show that this predictive controller is superior to the conventional PID controller in terms of convergence characteristics, and also show that this controller expands the maximum allowable time-delay for a system. Since the proposed predictor does not require a specific model for the plant-it requires only stochastic information on the outputs-, it can be applied to the control of general nonlinear systems.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115244597","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 : 1999-07-12DOI: 10.1109/ISIE.1999.798696
B.S. Lee, R. Krishnan
A variant of a low cost, four-quadrant converter topology for permanent magnet brushless DC (PMBDC) motor drives is proposed in this paper. It has the advantage of variable DC input voltage to the machine through a buck-boost front-end power stage and hence low torque ripple at very low speeds, a desirable feature in high performance applications. It has a fixed commutation voltage, which is equal to the DC source voltage. Further, it is proved that the proposed power converter topology will enable the maximum extraction of power from PMBDC motor drives. In addition, the energization and commutation of machine phases can be achieved independently. Because of these features, the proposed topology provides high operational reliability for the motor drives.
{"title":"A variable voltage converter topology for permanent-magnet brushless DC motor drives using buck-boost front-end power stage","authors":"B.S. Lee, R. Krishnan","doi":"10.1109/ISIE.1999.798696","DOIUrl":"https://doi.org/10.1109/ISIE.1999.798696","url":null,"abstract":"A variant of a low cost, four-quadrant converter topology for permanent magnet brushless DC (PMBDC) motor drives is proposed in this paper. It has the advantage of variable DC input voltage to the machine through a buck-boost front-end power stage and hence low torque ripple at very low speeds, a desirable feature in high performance applications. It has a fixed commutation voltage, which is equal to the DC source voltage. Further, it is proved that the proposed power converter topology will enable the maximum extraction of power from PMBDC motor drives. In addition, the energization and commutation of machine phases can be achieved independently. Because of these features, the proposed topology provides high operational reliability for the motor drives.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121017542","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 : 1999-07-12DOI: 10.1109/ISIE.1999.801812
Ming-Sheng Yang, Ho-Lung Hung, Hung-Ching Lu
A design approach of decentralized stabilizing variable structure control for perturbed large-scale systems with delays in state variables is proposed in this paper. The control design includes both the decentralized variable structure control law and an integral type of switching hyperplane. First, the decentralized control law is derived in such a way that the global reaching condition is satisfied, so that the sliding mode occurs in each subsystem. Moreover, a switching hyperplane is designed to force the initial states of the overall system to lie on the sliding hyperplane when time is at zero, and the stability degree of the overall system in sliding mode is achieved by choosing the elements of the hyperplane matrix. The proposed design approach does not need the solution of the Lyapunov equation or Riccati equation. The robust performance in sliding mode is discussed in detail. Finally, a numerical example is given to demonstrate the results.
{"title":"Design of decentralized stabilizing variable structure controller for perturbed large-scale systems with delays in state","authors":"Ming-Sheng Yang, Ho-Lung Hung, Hung-Ching Lu","doi":"10.1109/ISIE.1999.801812","DOIUrl":"https://doi.org/10.1109/ISIE.1999.801812","url":null,"abstract":"A design approach of decentralized stabilizing variable structure control for perturbed large-scale systems with delays in state variables is proposed in this paper. The control design includes both the decentralized variable structure control law and an integral type of switching hyperplane. First, the decentralized control law is derived in such a way that the global reaching condition is satisfied, so that the sliding mode occurs in each subsystem. Moreover, a switching hyperplane is designed to force the initial states of the overall system to lie on the sliding hyperplane when time is at zero, and the stability degree of the overall system in sliding mode is achieved by choosing the elements of the hyperplane matrix. The proposed design approach does not need the solution of the Lyapunov equation or Riccati equation. The robust performance in sliding mode is discussed in detail. Finally, a numerical example is given to demonstrate the results.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125000870","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 : 1999-07-12DOI: 10.1109/ISIE.1999.798657
G. Minas, J. S. Martins, C. Couto
Pulse width modulation techniques (PWM), introduced two decades ago, are the most used methods to control the voltage and frequency supplied to electrical AC machines. This paper describes a pulse width modulator based on the voltage space vectors technique that accepts voltage demands in dq coordinates and generates three phase PWM waveforms to drive a variable frequency voltage-source inverter. A scheme based on a high performance 16-bit standard microcontroller with minimum of additional hardware is used, which allows a flexible and economical solution. The output frequency of the modulator can be varied in a large range and with a good resolution. Experimental data obtained from an induction motor drive are presented.
{"title":"A microcontroller based voltage space vector modulator suitable for induction motor drives","authors":"G. Minas, J. S. Martins, C. Couto","doi":"10.1109/ISIE.1999.798657","DOIUrl":"https://doi.org/10.1109/ISIE.1999.798657","url":null,"abstract":"Pulse width modulation techniques (PWM), introduced two decades ago, are the most used methods to control the voltage and frequency supplied to electrical AC machines. This paper describes a pulse width modulator based on the voltage space vectors technique that accepts voltage demands in dq coordinates and generates three phase PWM waveforms to drive a variable frequency voltage-source inverter. A scheme based on a high performance 16-bit standard microcontroller with minimum of additional hardware is used, which allows a flexible and economical solution. The output frequency of the modulator can be varied in a large range and with a good resolution. Experimental data obtained from an induction motor drive are presented.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122392490","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 : 1999-07-12DOI: 10.1109/ISIE.1999.797014
G. Garcea
Application domain specific processors are becoming more and more appealing because of their peculiar feature of flexibility in terms of number of algorithms which one single architecture can execute and also in terms of the possible computational improvement due to the increase of parallelism. The specific domain chosen is the family of Jacobi algorithms which are often used in the field of adaptative beamforming of radar signals. The architecture chosen should be weakly programmable. The idea is to derive in a systematic way a control program to be downloaded on a simulator of the processor to obtain quantitative information about the performance on the execution of every algorithm. Moreover some techniques to improve, from a qualitative point of view, the parallelization of execution are applied, suggested by the particular structure of the Jacobi algorithms.
{"title":"Derivation of dataflow networks for a domain specific applications","authors":"G. Garcea","doi":"10.1109/ISIE.1999.797014","DOIUrl":"https://doi.org/10.1109/ISIE.1999.797014","url":null,"abstract":"Application domain specific processors are becoming more and more appealing because of their peculiar feature of flexibility in terms of number of algorithms which one single architecture can execute and also in terms of the possible computational improvement due to the increase of parallelism. The specific domain chosen is the family of Jacobi algorithms which are often used in the field of adaptative beamforming of radar signals. The architecture chosen should be weakly programmable. The idea is to derive in a systematic way a control program to be downloaded on a simulator of the processor to obtain quantitative information about the performance on the execution of every algorithm. Moreover some techniques to improve, from a qualitative point of view, the parallelization of execution are applied, suggested by the particular structure of the Jacobi algorithms.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122787364","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 : 1999-07-12DOI: 10.1109/ISIE.1999.801810
S. Uran, K. Jezernik
In the paper a continuous sliding mode impedance robot task space controller is presented. Continuous sliding mode was introduced into the robot task space impedance control in order to assure robustness of the control approach to robot dynamic parameters changes and in order to achieve simple implementation of the control algorithm. The analysis of the robot dynamic model is represented from which robot singularity points are determined and the range for the estimated value of robot inertia is obtained. The control algorithm is designed and the simulation and experimental results are represented.
{"title":"Continuous sliding mode impedance control for robots","authors":"S. Uran, K. Jezernik","doi":"10.1109/ISIE.1999.801810","DOIUrl":"https://doi.org/10.1109/ISIE.1999.801810","url":null,"abstract":"In the paper a continuous sliding mode impedance robot task space controller is presented. Continuous sliding mode was introduced into the robot task space impedance control in order to assure robustness of the control approach to robot dynamic parameters changes and in order to achieve simple implementation of the control algorithm. The analysis of the robot dynamic model is represented from which robot singularity points are determined and the range for the estimated value of robot inertia is obtained. The control algorithm is designed and the simulation and experimental results are represented.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122794234","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 : 1999-07-12DOI: 10.1109/ISIE.1999.796888
F. Parasiliti, R. Petrella, M. Tursini
This paper presents the implementation of two techniques for phase current sensing based on a low cost last generation /spl mu/C DSP (TMS320F24x). The first one is based on the measurement of the current flowing in a shunt resistor put in the DC bus of the inverter, the second one is based on the measurement of the current flowing in shunt resistors put in series to the emitter of the IGBT for each lower leg of the inverter. The information provided by these sensors, together with the pulse width modulation (PWM) information, is used to reconstruct the motor phase currents. After a description of the two methods and the limitations they present, an application in case of an induction motor drive is illustrated in which the adjacent vector-space vector pulse width modulation (AV-SVPWM) technique is used to drive the inverter. Some aspects involving the non ideal behaviour of different parts of the system (presence of dead time, power switches driver delay, rise and settling time of the current, A/D conversion module sampling time) are investigated in details and the specific hardware implementation is discussed. Experimental results and comparisons between the two methods are presented.
{"title":"Low cost phase current sensing in DSP based AC drives","authors":"F. Parasiliti, R. Petrella, M. Tursini","doi":"10.1109/ISIE.1999.796888","DOIUrl":"https://doi.org/10.1109/ISIE.1999.796888","url":null,"abstract":"This paper presents the implementation of two techniques for phase current sensing based on a low cost last generation /spl mu/C DSP (TMS320F24x). The first one is based on the measurement of the current flowing in a shunt resistor put in the DC bus of the inverter, the second one is based on the measurement of the current flowing in shunt resistors put in series to the emitter of the IGBT for each lower leg of the inverter. The information provided by these sensors, together with the pulse width modulation (PWM) information, is used to reconstruct the motor phase currents. After a description of the two methods and the limitations they present, an application in case of an induction motor drive is illustrated in which the adjacent vector-space vector pulse width modulation (AV-SVPWM) technique is used to drive the inverter. Some aspects involving the non ideal behaviour of different parts of the system (presence of dead time, power switches driver delay, rise and settling time of the current, A/D conversion module sampling time) are investigated in details and the specific hardware implementation is discussed. Experimental results and comparisons between the two methods are presented.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131404283","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 : 1999-07-12DOI: 10.1109/ISIE.1999.801826
D. Hissel, P. Maussion, J. Faucher
The main objective of this paper is to show that fuzzy logic can be used for three different reasons at the same time: providing a powerful control law with high dynamic performances and robustness first; for nonlinear phenomena minimisation; and for algorithms soft commutation. This paper first presents an efficient onsite tuning strategy for a fuzzy logic PI controller, which is devoted to the speed control of a permanent magnet synchronous motor. This onsite tuning strategy is based on the experimental designs methodology. The obtained experimental results combine a high performances level with a very good robustness on an industrial benchmark. However, due to a static friction torque angular nonuniformity on the considered electromechanical system, some speed ripples appear during the steady-state. In this paper, the authors propose to take into account this nonlinear phenomenon in order to reduce the resulting speed ripples as much as possible without any torque compensation strategy and without reducing the performances of the control law on the chosen benchmark. Therefore, two fuzzy rules tables are proposed, one designed to act near the steady-state operating point and to reduce the speed ripples, another designed to act at some distance of this point. To avoid sharp modifications in the control value applied to the system, a fuzzy algorithms commutation between these two tables is proposed. Parameters of this algorithm commutation are tuned using a simplex optimisation algorithm. The provided experimental results show a significant reduction of the speed ripples without any alteration of the general system response.
{"title":"Speed ripples reduction of a non-linear loaded synchronous motor through fuzzy algorithms commutation","authors":"D. Hissel, P. Maussion, J. Faucher","doi":"10.1109/ISIE.1999.801826","DOIUrl":"https://doi.org/10.1109/ISIE.1999.801826","url":null,"abstract":"The main objective of this paper is to show that fuzzy logic can be used for three different reasons at the same time: providing a powerful control law with high dynamic performances and robustness first; for nonlinear phenomena minimisation; and for algorithms soft commutation. This paper first presents an efficient onsite tuning strategy for a fuzzy logic PI controller, which is devoted to the speed control of a permanent magnet synchronous motor. This onsite tuning strategy is based on the experimental designs methodology. The obtained experimental results combine a high performances level with a very good robustness on an industrial benchmark. However, due to a static friction torque angular nonuniformity on the considered electromechanical system, some speed ripples appear during the steady-state. In this paper, the authors propose to take into account this nonlinear phenomenon in order to reduce the resulting speed ripples as much as possible without any torque compensation strategy and without reducing the performances of the control law on the chosen benchmark. Therefore, two fuzzy rules tables are proposed, one designed to act near the steady-state operating point and to reduce the speed ripples, another designed to act at some distance of this point. To avoid sharp modifications in the control value applied to the system, a fuzzy algorithms commutation between these two tables is proposed. Parameters of this algorithm commutation are tuned using a simplex optimisation algorithm. The provided experimental results show a significant reduction of the speed ripples without any alteration of the general system response.","PeriodicalId":227402,"journal":{"name":"ISIE '99. Proceedings of the IEEE International Symposium on Industrial Electronics (Cat. No.99TH8465)","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127800712","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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