Pub Date : 2022-02-19DOI: 10.1080/18824889.2021.2019968
J. Takayama, Yuki Ohara, Wei Sun
Nondestructive inner inspection techniques are essential to certify the safety or health of concrete structures, and one of the important issues in these inspections is the detectability of thin air voids or cracks. In this study, we propose a novel method for discriminating the variety and estimating the thickness of air voids based on the microwave radar technique. Specifically, to distinguish air voids from other objects, the phase shift of the microwaves was analysed using time-frequency analysis. In addition, based on a simple parallel incidence model, microwave reflection and refraction analysis were conducted on homogeneous layers, and a particular relation was calculated between the reflectance and the air void thickness. The experimental performance of the functions to distinguish air voids was good, however, quantitative thickness estimation failed. Therefore, we introduced a novel sophisticated propagation path model based on ray-traced propagation, which provides a couple of propagation paths. Additionally, the attenuation feature of microwaves was also considered. A quantitative thickness estimation method was re-applied to the experimentally observed waveforms. The estimation accuracy improved by approximately 54%, and the validity of quantitative thickness estimation was confirmed.
{"title":"Nondestructive evaluation of air voids in concrete structures using microwave radar technique","authors":"J. Takayama, Yuki Ohara, Wei Sun","doi":"10.1080/18824889.2021.2019968","DOIUrl":"https://doi.org/10.1080/18824889.2021.2019968","url":null,"abstract":"Nondestructive inner inspection techniques are essential to certify the safety or health of concrete structures, and one of the important issues in these inspections is the detectability of thin air voids or cracks. In this study, we propose a novel method for discriminating the variety and estimating the thickness of air voids based on the microwave radar technique. Specifically, to distinguish air voids from other objects, the phase shift of the microwaves was analysed using time-frequency analysis. In addition, based on a simple parallel incidence model, microwave reflection and refraction analysis were conducted on homogeneous layers, and a particular relation was calculated between the reflectance and the air void thickness. The experimental performance of the functions to distinguish air voids was good, however, quantitative thickness estimation failed. Therefore, we introduced a novel sophisticated propagation path model based on ray-traced propagation, which provides a couple of propagation paths. Additionally, the attenuation feature of microwaves was also considered. A quantitative thickness estimation method was re-applied to the experimentally observed waveforms. The estimation accuracy improved by approximately 54%, and the validity of quantitative thickness estimation was confirmed.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132851611","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 : 2022-02-18DOI: 10.1080/18824889.2022.2032542
Shotaro Shibahara, Takuma Wakasa, K. Sawada
This paper proposes network weight functions and time-varying potential functions for obstacle avoidance of swarm robots in column formation. We consider a potential function whose exponent is the distance between the robots and the obstacle for obstacle avoidance. When a robot tries to avoid an obstacle while staying in a formation, it behaves oscillatory due to the imbalance between the attraction of staying in the formation and the repulsion of avoiding the obstacle. In addition, swarm robots may become stagnant in front of large obstacles. To solve these problems, we propose two methods. The first method is to weaken the strength of the connection between robots according to their relative distance. The second method is to change the shape of the potential function depending on the relative angle between the robot and the obstacle. Numerical examples show that these methods reduce the oscillatory of the robot and alleviate the stagnation in front of the obstacle.
{"title":"Network weight and time-varying potential function for obstacle avoidance of swarm robots in column formation","authors":"Shotaro Shibahara, Takuma Wakasa, K. Sawada","doi":"10.1080/18824889.2022.2032542","DOIUrl":"https://doi.org/10.1080/18824889.2022.2032542","url":null,"abstract":"This paper proposes network weight functions and time-varying potential functions for obstacle avoidance of swarm robots in column formation. We consider a potential function whose exponent is the distance between the robots and the obstacle for obstacle avoidance. When a robot tries to avoid an obstacle while staying in a formation, it behaves oscillatory due to the imbalance between the attraction of staying in the formation and the repulsion of avoiding the obstacle. In addition, swarm robots may become stagnant in front of large obstacles. To solve these problems, we propose two methods. The first method is to weaken the strength of the connection between robots according to their relative distance. The second method is to change the shape of the potential function depending on the relative angle between the robot and the obstacle. Numerical examples show that these methods reduce the oscillatory of the robot and alleviate the stagnation in front of the obstacle.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127870276","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 : 2022-02-15DOI: 10.1080/18824889.2022.2029033
Shumpei Kubosawa, Takashi Onishi, Y. Tsuruoka
We present a novel framework for controlling non-steady situations in chemical plants to address the behavioural gaps between the simulator for constructing the reinforcement learning-based controller and the real plant considered for deploying the framework. In the field of reinforcement learning, the performance deterioration problem owing to such gaps are referred to as simulation-to-reality gaps (Sim-to-Real gaps). These gaps are triggered by multiple factors, including modelling errors on the simulators, incorrect state identifications, and unpredicted disturbances on the real situations. We focus on these issues and divided the objective of performing optimal control under gapped situations into three tasks, namely, (1) identifying the model parameters and current state, (2) optimizing the operation procedures, and (3) letting the real situations close to the simulated and predicted situations by adjusting the control inputs. Each task is assigned to a reinforcement learning agent and trained individually. After the training, the agents are integrated and collaborate on the original objective. We present the evaluation of our method in an actual chemical distillation plant, which demonstrates that our system successfully narrows down the gaps due to the emulated disturbance of a weather change (heavy rain) as well as the modelling errors and achieves the desired states.
{"title":"Sim-to-real transfer in reinforcement learning-based, non-steady-state control for chemical plants","authors":"Shumpei Kubosawa, Takashi Onishi, Y. Tsuruoka","doi":"10.1080/18824889.2022.2029033","DOIUrl":"https://doi.org/10.1080/18824889.2022.2029033","url":null,"abstract":"We present a novel framework for controlling non-steady situations in chemical plants to address the behavioural gaps between the simulator for constructing the reinforcement learning-based controller and the real plant considered for deploying the framework. In the field of reinforcement learning, the performance deterioration problem owing to such gaps are referred to as simulation-to-reality gaps (Sim-to-Real gaps). These gaps are triggered by multiple factors, including modelling errors on the simulators, incorrect state identifications, and unpredicted disturbances on the real situations. We focus on these issues and divided the objective of performing optimal control under gapped situations into three tasks, namely, (1) identifying the model parameters and current state, (2) optimizing the operation procedures, and (3) letting the real situations close to the simulated and predicted situations by adjusting the control inputs. Each task is assigned to a reinforcement learning agent and trained individually. After the training, the agents are integrated and collaborate on the original objective. We present the evaluation of our method in an actual chemical distillation plant, which demonstrates that our system successfully narrows down the gaps due to the emulated disturbance of a weather change (heavy rain) as well as the modelling errors and achieves the desired states.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128229140","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 : 2022-02-06DOI: 10.1080/18824889.2022.2029032
Yasushi Iwatani
Rimless wheel robots are ground robots with high mobility on a variety of uneven terrains. Rimless wheels have no rims or tires but only spokes, and rimless wheel robots move along with collisions of spokes with the ground. Their equations of collision have been derived from a conservation law of angular momentum only for the simplest type of rimless wheel robots. It is uncertain when the conservation law is satisfied or violated, and what happens in the violated case. Complete equations of collision are unknown even for the simplest type of rimless wheel robots. This paper considers three types of rimless wheel robots including the simplest type and provides complete equations of collision for each type of rimless wheel robots. In addition, this paper describes properties of the dynamics during collision. Some of them reveal relationships between the dynamics of the three types of rimless wheel robots. Another shows a relationship between the dynamics of rimless wheels and circular wheels. They also clarify when the conservation law of angular momentum is satisfied or violated, and what happens in each case.
{"title":"Dynamics of rimless wheel robots during collision","authors":"Yasushi Iwatani","doi":"10.1080/18824889.2022.2029032","DOIUrl":"https://doi.org/10.1080/18824889.2022.2029032","url":null,"abstract":"Rimless wheel robots are ground robots with high mobility on a variety of uneven terrains. Rimless wheels have no rims or tires but only spokes, and rimless wheel robots move along with collisions of spokes with the ground. Their equations of collision have been derived from a conservation law of angular momentum only for the simplest type of rimless wheel robots. It is uncertain when the conservation law is satisfied or violated, and what happens in the violated case. Complete equations of collision are unknown even for the simplest type of rimless wheel robots. This paper considers three types of rimless wheel robots including the simplest type and provides complete equations of collision for each type of rimless wheel robots. In addition, this paper describes properties of the dynamics during collision. Some of them reveal relationships between the dynamics of the three types of rimless wheel robots. Another shows a relationship between the dynamics of rimless wheels and circular wheels. They also clarify when the conservation law of angular momentum is satisfied or violated, and what happens in each case.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127250331","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 : 2021-06-16DOI: 10.1080/18824889.2021.1894022
Kota Mukai, N. Hara, K. Konishi
ABSTRACT A quad-maran unmanned vessel is a new type of unmanned surface vessel for the automatic collection of various environmental data in aquaculture fields. We propose a fault detection and control scheme for a possible thrust decrease failure of quad-maran vessels. The fault detection and control are based on moving horizon estimation and model predictive control. The proposed estimation and control scheme is experimentally validated.
{"title":"Experimental validation of propulsion fault detection system using moving horizon estimation in quad-maran unmanned vessel","authors":"Kota Mukai, N. Hara, K. Konishi","doi":"10.1080/18824889.2021.1894022","DOIUrl":"https://doi.org/10.1080/18824889.2021.1894022","url":null,"abstract":"ABSTRACT A quad-maran unmanned vessel is a new type of unmanned surface vessel for the automatic collection of various environmental data in aquaculture fields. We propose a fault detection and control scheme for a possible thrust decrease failure of quad-maran vessels. The fault detection and control are based on moving horizon estimation and model predictive control. The proposed estimation and control scheme is experimentally validated.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"215 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116828474","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 : 2021-06-16DOI: 10.1080/18824889.2021.1918392
Ryuichiro Yoshida, Yuki Tanigawa, Hiroshi Okajima, N. Matsunaga
Control systems achieve the desired performance with the model-based controller if the dynamical model of the actual plant is given with sufficient accuracy. However, if there exists a difference between the actual plant and its model dynamics, the model-based controller does not work well and does not achieve the intended desired performance. A model error compensator (MEC) is proposed for overcoming the model error in our previous study. Attaching the compensator for the model error to the actual plant, the output trajectory of the actual plant is made close to that of its model. Then, from the controller, the apparent difference in the dynamics can be smaller, and performance degradation is drastically reduced. MEC is useful for various control systems such as non-linear systems and the control systems with delay, and so on. In this paper, we propose an original design method of the filter parameters in MEC for systems with polytopic-type uncertainty and disturbances. First, we show an analysis method about the robust performance of MEC for the system with the polytopic type uncertainty based on an linear matrix inequality problem. The gain parameters in MEC is designed using particle swarm optimization and the presented analysis method. The effectiveness of the design method for the system with polytopic-type uncertainty and disturbance is evaluated using numerical examples.
{"title":"A design method of model error compensator for systems with polytopic-type uncertainty and disturbances","authors":"Ryuichiro Yoshida, Yuki Tanigawa, Hiroshi Okajima, N. Matsunaga","doi":"10.1080/18824889.2021.1918392","DOIUrl":"https://doi.org/10.1080/18824889.2021.1918392","url":null,"abstract":"Control systems achieve the desired performance with the model-based controller if the dynamical model of the actual plant is given with sufficient accuracy. However, if there exists a difference between the actual plant and its model dynamics, the model-based controller does not work well and does not achieve the intended desired performance. A model error compensator (MEC) is proposed for overcoming the model error in our previous study. Attaching the compensator for the model error to the actual plant, the output trajectory of the actual plant is made close to that of its model. Then, from the controller, the apparent difference in the dynamics can be smaller, and performance degradation is drastically reduced. MEC is useful for various control systems such as non-linear systems and the control systems with delay, and so on. In this paper, we propose an original design method of the filter parameters in MEC for systems with polytopic-type uncertainty and disturbances. First, we show an analysis method about the robust performance of MEC for the system with the polytopic type uncertainty based on an linear matrix inequality problem. The gain parameters in MEC is designed using particle swarm optimization and the presented analysis method. The effectiveness of the design method for the system with polytopic-type uncertainty and disturbance is evaluated using numerical examples.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114785838","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 : 2021-06-16DOI: 10.1080/18824889.2021.1932917
N. Sakamoto, S. Takai, Hiroshi Ito
{"title":"Special issue on SICE Annual Conference 2020","authors":"N. Sakamoto, S. Takai, Hiroshi Ito","doi":"10.1080/18824889.2021.1932917","DOIUrl":"https://doi.org/10.1080/18824889.2021.1932917","url":null,"abstract":"","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127061892","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 : 2021-06-16DOI: 10.1080/18824889.2021.1913879
I. Jikuya, D. Uchida, M. Kino, M. Kurita, Katsuhiko Yamada
A segmented mirror control system is indispensable for operating an astronomical telescope which is equipped with a segmented primary mirror. In this study, we focus on the distributed control system (DCS) proposed for Seimei telescope. An interesting hierarchical structure is found by analysing its zero–nonzero structure in the DCS, and then, 54 gains are reasonably classified into 4 groups. Design examples for selecting gains of the DCS are presented so that the closed loop pole locations are similar to those of the centralized control system (CCS). The freedom in the selections of gains by taking account of the hierarchical structure is shown to be effective by numerically evaluating the stability region and by optimizing the maximum distance between the closed loop poles of DCS and CCS.
{"title":"Structure of distributed control system in Seimei telescope","authors":"I. Jikuya, D. Uchida, M. Kino, M. Kurita, Katsuhiko Yamada","doi":"10.1080/18824889.2021.1913879","DOIUrl":"https://doi.org/10.1080/18824889.2021.1913879","url":null,"abstract":"A segmented mirror control system is indispensable for operating an astronomical telescope which is equipped with a segmented primary mirror. In this study, we focus on the distributed control system (DCS) proposed for Seimei telescope. An interesting hierarchical structure is found by analysing its zero–nonzero structure in the DCS, and then, 54 gains are reasonably classified into 4 groups. Design examples for selecting gains of the DCS are presented so that the closed loop pole locations are similar to those of the centralized control system (CCS). The freedom in the selections of gains by taking account of the hierarchical structure is shown to be effective by numerically evaluating the stability region and by optimizing the maximum distance between the closed loop poles of DCS and CCS.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116411069","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 : 2021-06-16DOI: 10.1080/18824889.2021.1919400
K. Isomoto, D. Kushida
We propose a monitoring system for accidental falling of patients using a point cloud dataset (PCD) of the depth camera-captured images. The conventional system requires the PCD to comprise images showing the bed top view. Consequently, the depth camera installation location is restricted. Therefore, we propose a new system with a new PCD generation method. This system enabled PCD correction, corrected dataset division, human location estimation, and fall risk calculation. The Microsoft Kinect sensor was employed as a depth camera in the validation. We demonstrate that the pitch angle can be set between and within the depth camera measurable range to image the subject's movements. These images were utilized in risk estimation. Further, the horizontal distance from the side edge of the bed and the height from the ground were greater than 1.0 m. Under these conditions, the PCD can be corrected into a bed top view dataset, and can help in estimating the fall risk.
{"title":"Improvement of a depth camera installation for fall risk estimation","authors":"K. Isomoto, D. Kushida","doi":"10.1080/18824889.2021.1919400","DOIUrl":"https://doi.org/10.1080/18824889.2021.1919400","url":null,"abstract":"We propose a monitoring system for accidental falling of patients using a point cloud dataset (PCD) of the depth camera-captured images. The conventional system requires the PCD to comprise images showing the bed top view. Consequently, the depth camera installation location is restricted. Therefore, we propose a new system with a new PCD generation method. This system enabled PCD correction, corrected dataset division, human location estimation, and fall risk calculation. The Microsoft Kinect sensor was employed as a depth camera in the validation. We demonstrate that the pitch angle can be set between and within the depth camera measurable range to image the subject's movements. These images were utilized in risk estimation. Further, the horizontal distance from the side edge of the bed and the height from the ground were greater than 1.0 m. Under these conditions, the PCD can be corrected into a bed top view dataset, and can help in estimating the fall risk.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122019360","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 : 2021-04-27DOI: 10.1080/18824889.2021.1896642
Y. Hasama, Yoshiaki Saito, Jun Ohkubo
The first modelling to predict the moisture content of perlite in container cultivation was performed. In recent years, information technology-based agriculture (smart agriculture), such as automated cultivation of crops, has received considerable attention. One of the important issues in crop cultivation is how to control soil moisture content to achieve optimal conditions for plants. Models that accurately predict the water content in soil are needed. Perlite is often used in containers as a hydroponic soil. Although methods to maintain the moisture content in containers have been studied in the past, there has been no study on how to maintain the moisture content of perlite. In this study, we develop a measurement system, created a model for the water content and drainage of perlite in a container, and analysed the data. The results reveal for the first time a nonlinear trend in the moisture of perlite in containers. The nonlinear model obtained can be used to establish more efficient water supply methods for perlite used in container cultivation.
{"title":"Water storage and drainage in perlite in container cultivation","authors":"Y. Hasama, Yoshiaki Saito, Jun Ohkubo","doi":"10.1080/18824889.2021.1896642","DOIUrl":"https://doi.org/10.1080/18824889.2021.1896642","url":null,"abstract":"The first modelling to predict the moisture content of perlite in container cultivation was performed. In recent years, information technology-based agriculture (smart agriculture), such as automated cultivation of crops, has received considerable attention. One of the important issues in crop cultivation is how to control soil moisture content to achieve optimal conditions for plants. Models that accurately predict the water content in soil are needed. Perlite is often used in containers as a hydroponic soil. Although methods to maintain the moisture content in containers have been studied in the past, there has been no study on how to maintain the moisture content of perlite. In this study, we develop a measurement system, created a model for the water content and drainage of perlite in a container, and analysed the data. The results reveal for the first time a nonlinear trend in the moisture of perlite in containers. The nonlinear model obtained can be used to establish more efficient water supply methods for perlite used in container cultivation.","PeriodicalId":413922,"journal":{"name":"SICE journal of control, measurement, and system integration","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124651331","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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