Pub Date : 2000-10-10DOI: 10.1109/NAECON.2000.894962
A. Derdiyok, M. Guven, N. Inanç, H. Rehman, Longya Xu
This paper has attempted to improve the speed control performance of an indirect field oriented (IFO) induction motor drive system by using a continuous sliding mode controller. The proposed continuous sliding mode controller is robust to load changes and system disturbances which are unique features of discontinuous sliding mode control. Also it is free from chattering which is the main problem of discontinuous sliding mode control. The proposed controller can also overcome the performance degradation and avoid tedious tuning process associated with the PI controller. The results of PI and sliding mode controller (SMC) are compared through extensive simulation and experimental work. These results prove that the proposed controller is robust to load changes and system disturbances and can also follow different command trajectories very well without re-tuning of the controller.
{"title":"A DSP-based indirect field oriented induction machine control by using chattering-free sliding mode","authors":"A. Derdiyok, M. Guven, N. Inanç, H. Rehman, Longya Xu","doi":"10.1109/NAECON.2000.894962","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894962","url":null,"abstract":"This paper has attempted to improve the speed control performance of an indirect field oriented (IFO) induction motor drive system by using a continuous sliding mode controller. The proposed continuous sliding mode controller is robust to load changes and system disturbances which are unique features of discontinuous sliding mode control. Also it is free from chattering which is the main problem of discontinuous sliding mode control. The proposed controller can also overcome the performance degradation and avoid tedious tuning process associated with the PI controller. The results of PI and sliding mode controller (SMC) are compared through extensive simulation and experimental work. These results prove that the proposed controller is robust to load changes and system disturbances and can also follow different command trajectories very well without re-tuning of the controller.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114541163","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894893
K. Livingston, J. Seitzer
We present an implementation of a data parallel system. A sequential knowledge-based deductive and inductive system, INDED, is transformed into a parallel system. In this parallel system the learning algorithm, the fundamental component of the induction engine, is distributed among many processors. The parallel system is implemented with a master node and several worker nodes. The master node is responsible for coordinating the activity of the worker nodes, and organizing the overall learning process. All the worker nodes share the processing of the basic induction algorithms and report their results to the master node. The goal of the data parallel system is to produce, more efficiently, rules that are equal to or better than those produced by the serial system. In this paper, we present the architecture of the parallel version of INDED, and comparison results involving execution speeds and quality of generated rules of the new parallel system to those of the serial system.
{"title":"A data parallel implementation of an intelligent reasoning system","authors":"K. Livingston, J. Seitzer","doi":"10.1109/NAECON.2000.894893","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894893","url":null,"abstract":"We present an implementation of a data parallel system. A sequential knowledge-based deductive and inductive system, INDED, is transformed into a parallel system. In this parallel system the learning algorithm, the fundamental component of the induction engine, is distributed among many processors. The parallel system is implemented with a master node and several worker nodes. The master node is responsible for coordinating the activity of the worker nodes, and organizing the overall learning process. All the worker nodes share the processing of the basic induction algorithms and report their results to the master node. The goal of the data parallel system is to produce, more efficiently, rules that are equal to or better than those produced by the serial system. In this paper, we present the architecture of the parallel version of INDED, and comparison results involving execution speeds and quality of generated rules of the new parallel system to those of the serial system.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122664818","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894909
B. W. Kowal
Propulsion Controlled Aircraft (PCA) techniques address the problem of controlling an aircraft through only the propulsion system after the primary flight control system has failed. There have been several major commercial accidents in which over 1200 people have lost their lives due to these type of accidents. In addition during the Vietnam War it is estimated that 18% of the aircraft lost...around 1800 aircraft...were lost due to flight control system failures. PCA techniques have been shown to have the potential to prevent some of these commercial aircraft accidents and have also been shown to have the potential to significantly improve military aircraft survivability to flight control system damage or failures. This paper will present a brief history of accidents that might have been avoided through PCA techniques and will apply the modern nonlinear Variable Structure Control System (VSCS) method to the aircraft PCA problem for a contemporary large transport aircraft. The VSCS controller will be compared with a classical linear controller for the task of glide slope tracking. The robustness of the VSCS controller to sensor noise and model uncertainty will be evaluated. It will be shown that the VSCS controller performs as well as the classical controller with improved robustness to model uncertainty.
{"title":"A variable structure control system for the propulsion controlled automatic landing of a contemporary large transport aircraft","authors":"B. W. Kowal","doi":"10.1109/NAECON.2000.894909","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894909","url":null,"abstract":"Propulsion Controlled Aircraft (PCA) techniques address the problem of controlling an aircraft through only the propulsion system after the primary flight control system has failed. There have been several major commercial accidents in which over 1200 people have lost their lives due to these type of accidents. In addition during the Vietnam War it is estimated that 18% of the aircraft lost...around 1800 aircraft...were lost due to flight control system failures. PCA techniques have been shown to have the potential to prevent some of these commercial aircraft accidents and have also been shown to have the potential to significantly improve military aircraft survivability to flight control system damage or failures. This paper will present a brief history of accidents that might have been avoided through PCA techniques and will apply the modern nonlinear Variable Structure Control System (VSCS) method to the aircraft PCA problem for a contemporary large transport aircraft. The VSCS controller will be compared with a classical linear controller for the task of glide slope tracking. The robustness of the VSCS controller to sensor noise and model uncertainty will be evaluated. It will be shown that the VSCS controller performs as well as the classical controller with improved robustness to model uncertainty.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123314802","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894900
J. Bowman
Techniques are presented for improving the computational performance of radar cross section (RCS) prediction for aircraft. The motivation is to bring RCS and other electromagnetic requirements into a multidisciplinary, integrated design environment where optimization is likely to be employed. Techniques directly applicable to the method of moments and high frequency approximations are discussed.
{"title":"Methods for rapid computation of RCS in aircraft design","authors":"J. Bowman","doi":"10.1109/NAECON.2000.894900","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894900","url":null,"abstract":"Techniques are presented for improving the computational performance of radar cross section (RCS) prediction for aircraft. The motivation is to bring RCS and other electromagnetic requirements into a multidisciplinary, integrated design environment where optimization is likely to be employed. Techniques directly applicable to the method of moments and high frequency approximations are discussed.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126013592","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894932
S. Sung, Jang-Gyu Lee, T. Kang, J. Song
In this paper, presented are a resonance type accelerometer, its implementation and results of performance test. The structure and principle of resonance type accelerometer are illustrated concisely. A pure surface micromachining technology is used for the structure manufacturing. Fundamental idea of this sensor is to detect variation of effective stiffness from parallel-plated electrostatic resonator. Since resonant accelerometer needs to keep track of the system's resonance point, a feedback loop called self-sustained oscillation loop is designed. The resonant point and its stability robustness are analyzed using nonlinear control methodologies, i.e., describing function method and extended Nyquist stability criterion. Environmental test and theoretical analysis confirmed that the oscillation loop is very robust to external disturbances.
{"title":"Development of a tunable resonant accelerometer with self-sustained oscillation loop","authors":"S. Sung, Jang-Gyu Lee, T. Kang, J. Song","doi":"10.1109/NAECON.2000.894932","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894932","url":null,"abstract":"In this paper, presented are a resonance type accelerometer, its implementation and results of performance test. The structure and principle of resonance type accelerometer are illustrated concisely. A pure surface micromachining technology is used for the structure manufacturing. Fundamental idea of this sensor is to detect variation of effective stiffness from parallel-plated electrostatic resonator. Since resonant accelerometer needs to keep track of the system's resonance point, a feedback loop called self-sustained oscillation loop is designed. The resonant point and its stability robustness are analyzed using nonlinear control methodologies, i.e., describing function method and extended Nyquist stability criterion. Environmental test and theoretical analysis confirmed that the oscillation loop is very robust to external disturbances.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"38 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130841664","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894928
Yunxian Huang, Wei Yan, Zilin Song
In this paper an evolutionary neural network (ENN) based call admission control (CAC) algorithm for asynchronous transfer mode (ATM) networks is proposed. The ENN is used as a controller to decide whether a new call set up request with some quality of service requirement will be accepted or rejected. The control method is applicable to heterogeneous traffic sources. The designed model has several new features that benefit its efficiency and performance. The ENN dimension is independent of the number of traffic classes. The new evolutionary algorithm is proposed not only to overcome the local extreme value problem in conventional neural network training algorithms but also to simplify the neural network structure and enhance the capabilities of generalization. Simulation results show that our ENN based control method is more robust and accurate than other conventional control methods.
{"title":"Call admission control in ATM networks based on evolutionary neural networks","authors":"Yunxian Huang, Wei Yan, Zilin Song","doi":"10.1109/NAECON.2000.894928","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894928","url":null,"abstract":"In this paper an evolutionary neural network (ENN) based call admission control (CAC) algorithm for asynchronous transfer mode (ATM) networks is proposed. The ENN is used as a controller to decide whether a new call set up request with some quality of service requirement will be accepted or rejected. The control method is applicable to heterogeneous traffic sources. The designed model has several new features that benefit its efficiency and performance. The ENN dimension is independent of the number of traffic classes. The new evolutionary algorithm is proposed not only to overcome the local extreme value problem in conventional neural network training algorithms but also to simplify the neural network structure and enhance the capabilities of generalization. Simulation results show that our ENN based control method is more robust and accurate than other conventional control methods.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133812603","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894968
G. Coxson
The imbalance of a binary code with elements either +1 or -1 is the number of -1 elements subtracted from the number of +1 elements. A balanced code is one with 0 imbalance. Balanced codes are often used for pulse compression because the DC response of a linear pulse compression module is proportional to the imbalance. A nonzero DC bias combined with an unbalanced code produces a nonzero output. In a radar signal processor, this can mean susceptibility to false alarms from signals that alias to DC at pulse compressor input. This paper examines a common radar signal processor subchain for which some imbalance in pulse compression codes can reduce bias sensitivity. The chain consists of R/theta limiter, pulse compressor and I/sup 2/+Q/sup 2/ modules. It is shown that for an input consisting of DC bias and additive Gaussian noise, there is a nonzero value for the code imbalance for which the mean and variance of the output are insensitive to the magnitude and phase of the input bias.
{"title":"Where binary code imbalance decreases DC bias sensitivity","authors":"G. Coxson","doi":"10.1109/NAECON.2000.894968","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894968","url":null,"abstract":"The imbalance of a binary code with elements either +1 or -1 is the number of -1 elements subtracted from the number of +1 elements. A balanced code is one with 0 imbalance. Balanced codes are often used for pulse compression because the DC response of a linear pulse compression module is proportional to the imbalance. A nonzero DC bias combined with an unbalanced code produces a nonzero output. In a radar signal processor, this can mean susceptibility to false alarms from signals that alias to DC at pulse compressor input. This paper examines a common radar signal processor subchain for which some imbalance in pulse compression codes can reduce bias sensitivity. The chain consists of R/theta limiter, pulse compressor and I/sup 2/+Q/sup 2/ modules. It is shown that for an input consisting of DC bias and additive Gaussian noise, there is a nonzero value for the code imbalance for which the mean and variance of the output are insensitive to the magnitude and phase of the input bias.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131039765","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894902
P. Detweiler, K.M. Pasala
Some applications, such as space-based radar, require wide-angle scanning and very narrow beamwidths. Hybrid antennas, which are reflector antennas fed by arrays, may provide an alternative to the use of large array antennas in these applications. This paper presents a numerical method for shaping the reflector to maximize the collected energy over the desired scan range. By experimenting with various feed array sizes and shapes, and using the methods presented herein to find the optimal reflector shape at each step, one may arrive at designs that minimize the feed array surface area while meeting various system design objectives such as scan range, aperture size, and aperture utilization. Optimization examples are provided for several feed array configurations, along with analyses of the resulting performance over the desired scan range.
{"title":"Wide-angle scanning with reflector antennas: a new design technique","authors":"P. Detweiler, K.M. Pasala","doi":"10.1109/NAECON.2000.894902","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894902","url":null,"abstract":"Some applications, such as space-based radar, require wide-angle scanning and very narrow beamwidths. Hybrid antennas, which are reflector antennas fed by arrays, may provide an alternative to the use of large array antennas in these applications. This paper presents a numerical method for shaping the reflector to maximize the collected energy over the desired scan range. By experimenting with various feed array sizes and shapes, and using the methods presented herein to find the optimal reflector shape at each step, one may arrive at designs that minimize the feed array surface area while meeting various system design objectives such as scan range, aperture size, and aperture utilization. Optimization examples are provided for several feed array configurations, along with analyses of the resulting performance over the desired scan range.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115934106","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894903
C. Lee, J. Chun
In this paper a new iterative calibration algorithm for an asynchronous CDMA-based antenna array in the presence of unknown gain and phase errors is presented. The algorithm is applicable to a nonuniform array where the number of users could be greater than the number of antennas, and does not require a prior knowledge of the DOAs of the signals of any user. The method requires the code sequence of a reference user only. The proposed algorithm provides us with the joint estimates of the DOAs and the multi-path impulse response of the used signal sources as well as the calibration of the sensor gains and phases, even under multiple access interference. The algorithm is near-far resistant and thus well suited for multi-path fading channel.
{"title":"A subspace-based online calibration algorithm for an asynchronous CDMA-based antenna array","authors":"C. Lee, J. Chun","doi":"10.1109/NAECON.2000.894903","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894903","url":null,"abstract":"In this paper a new iterative calibration algorithm for an asynchronous CDMA-based antenna array in the presence of unknown gain and phase errors is presented. The algorithm is applicable to a nonuniform array where the number of users could be greater than the number of antennas, and does not require a prior knowledge of the DOAs of the signals of any user. The method requires the code sequence of a reference user only. The proposed algorithm provides us with the joint estimates of the DOAs and the multi-path impulse response of the used signal sources as well as the calibration of the sensor gains and phases, even under multiple access interference. The algorithm is near-far resistant and thus well suited for multi-path fading channel.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"280 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116229612","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 : 2000-10-10DOI: 10.1109/NAECON.2000.894966
Mau-Tsuen Yang, T. Gandhi, R. Kasturi, L. Coraor, O. Camps, J. McCandless
The High Speed Civil Transport (HSCT) supersonic commercial aircraft under development by National Aeronautics and Space Administration (NASA) and its partners is expected to include an eXternal Visibility System (XVS) to aid the pilot's limited view through their cockpit windows. XVS obtains video images using high resolution digital cameras mounted on the aircraft and directed outside the aircraft. The images captured by the XVS provide an opportunity for automatic computer analysis in real-time to alert pilots of potential hazards in the flight path. The system is useful to help pilots make decisions and avoid air collision. In this paper, we describe the design, implementation, and evaluation of such a computer vision system. Using this system, real-time image data was recently obtained successfully from night tests conducted at NASA Langley Research Center. The system successfully detected and tracked translating objects in real-time during the night test. The system is described in detail so that other researchers can easily replicate the work.
{"title":"Real-time obstacle detection system for high speed civil transport supersonic aircraft","authors":"Mau-Tsuen Yang, T. Gandhi, R. Kasturi, L. Coraor, O. Camps, J. McCandless","doi":"10.1109/NAECON.2000.894966","DOIUrl":"https://doi.org/10.1109/NAECON.2000.894966","url":null,"abstract":"The High Speed Civil Transport (HSCT) supersonic commercial aircraft under development by National Aeronautics and Space Administration (NASA) and its partners is expected to include an eXternal Visibility System (XVS) to aid the pilot's limited view through their cockpit windows. XVS obtains video images using high resolution digital cameras mounted on the aircraft and directed outside the aircraft. The images captured by the XVS provide an opportunity for automatic computer analysis in real-time to alert pilots of potential hazards in the flight path. The system is useful to help pilots make decisions and avoid air collision. In this paper, we describe the design, implementation, and evaluation of such a computer vision system. Using this system, real-time image data was recently obtained successfully from night tests conducted at NASA Langley Research Center. The system successfully detected and tracked translating objects in real-time during the night test. The system is described in detail so that other researchers can easily replicate the work.","PeriodicalId":171131,"journal":{"name":"Proceedings of the IEEE 2000 National Aerospace and Electronics Conference. NAECON 2000. Engineering Tomorrow (Cat. No.00CH37093)","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123197607","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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