Pub Date : 2015-06-16DOI: 10.1109/RAST.2015.7208340
Salman Nasir, I. Iqbal, Z. Ali, A. Shahzad
Digital Elevation Model (DEM) is crucial for several purposes like town planning, hydrological analysis, land sliding, flash floods, earthquake, road construction, surface analysis, ortho-rectification of satellite imagery, 3D visualization, precise farming and forestry, base mapping, flight simulation and disaster management. Pleiades is a French constellation of very high resolution satellites. It acquires both panchromatic as well as multispectral imagery in Visible Near Infra-red (VNIR) range. The added benefit of Pleiades is that it provides tri stereo-pair imagery at 0.5m spatial resolution, unlike its other contemporary systems like Quickbird and IKONOS. Tri stereo-pair is used for Digital Terrain Model (DTM) and Digital Surface Model (DSM) extraction because of its backward and forward look angles. Moreover, Pleiades provides Rational Polynomial Coefficient (RPC) and sensor model data which augment the accuracy of its 3D products. Being a newly launched system, it provides fertile field for researchers to analyze the strengths and weaknesses of this system. This study explores the potential of Pleiades Tri stereo-pair in generating high resolution DEM, and comparing its accuracy with Shuttle Radar Topography Mission (SRTM) and Advanced Space Thermal Emission Radiometer (ASTER). In this study, data from space borne LiDAR (ICESat/GLAS) was used as a reference due to its reported unprecedented accuracy. Comparison of Pleiades with LiDAR resulted in an R2 of 0.92 with an RMSE of 5.2m. Similarly, comparison of SRTM and ASTER resulted in an R2 of 0.74 (RMSE 7.5m) and R2 0.84 (RMSE 6.6m), respectively.
{"title":"Accuracy assessment of digital elevation model generated from pleiades tri stereo-pair","authors":"Salman Nasir, I. Iqbal, Z. Ali, A. Shahzad","doi":"10.1109/RAST.2015.7208340","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208340","url":null,"abstract":"Digital Elevation Model (DEM) is crucial for several purposes like town planning, hydrological analysis, land sliding, flash floods, earthquake, road construction, surface analysis, ortho-rectification of satellite imagery, 3D visualization, precise farming and forestry, base mapping, flight simulation and disaster management. Pleiades is a French constellation of very high resolution satellites. It acquires both panchromatic as well as multispectral imagery in Visible Near Infra-red (VNIR) range. The added benefit of Pleiades is that it provides tri stereo-pair imagery at 0.5m spatial resolution, unlike its other contemporary systems like Quickbird and IKONOS. Tri stereo-pair is used for Digital Terrain Model (DTM) and Digital Surface Model (DSM) extraction because of its backward and forward look angles. Moreover, Pleiades provides Rational Polynomial Coefficient (RPC) and sensor model data which augment the accuracy of its 3D products. Being a newly launched system, it provides fertile field for researchers to analyze the strengths and weaknesses of this system. This study explores the potential of Pleiades Tri stereo-pair in generating high resolution DEM, and comparing its accuracy with Shuttle Radar Topography Mission (SRTM) and Advanced Space Thermal Emission Radiometer (ASTER). In this study, data from space borne LiDAR (ICESat/GLAS) was used as a reference due to its reported unprecedented accuracy. Comparison of Pleiades with LiDAR resulted in an R2 of 0.92 with an RMSE of 5.2m. Similarly, comparison of SRTM and ASTER resulted in an R2 of 0.74 (RMSE 7.5m) and R2 0.84 (RMSE 6.6m), respectively.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"355 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116680303","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208454
M. Yamazaki
In this paper, the newly-developed space systems engineering education tool “classroom pico-satellite HEPTA” is introduced. The objective of this pico-satellite HEPTA kit is easy to understand space systems engineering by using low-cost component over a short amount of time. It is based on former CubeSat development experience at Nihon University, SEEDS and SPROUT. This kit can provide learning opportunity to large number of students with varied background. The minute detail of HEPTA kit of hardware & software and outline of the hands-on training is introduced in this paper.
{"title":"Hands-on learning of space systems engineering by using classroom pico-satellite “HEPTA”","authors":"M. Yamazaki","doi":"10.1109/RAST.2015.7208454","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208454","url":null,"abstract":"In this paper, the newly-developed space systems engineering education tool “classroom pico-satellite HEPTA” is introduced. The objective of this pico-satellite HEPTA kit is easy to understand space systems engineering by using low-cost component over a short amount of time. It is based on former CubeSat development experience at Nihon University, SEEDS and SPROUT. This kit can provide learning opportunity to large number of students with varied background. The minute detail of HEPTA kit of hardware & software and outline of the hands-on training is introduced in this paper.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124806719","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208390
M. Cihan, M. O. Kaya
Dynamic stability of a free flight aerospace vehicle is investigated in this paper. Firstly, the slender rocket body is modeled as a classic uniform beam that subjected to constant end rocket thrust. The one-dimensional free-free beam under follower force is established for structural model to discover dynamic stability. Equations of motion of vehicle is derived by applying extended Hamilton's principle for non-conservative systems. Natural frequencies of rocket are determined and critical thrust is obtained by using finite element method. It is noted that, transverse vibrational modes differ by thrust value. Secondly, natural frequencies of non-homogeneous beam are discussed by considering that rocket has different types and number of stages. Numerical results for both cases are represented.
{"title":"On the dynamic stability of a rocket under constant thrust","authors":"M. Cihan, M. O. Kaya","doi":"10.1109/RAST.2015.7208390","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208390","url":null,"abstract":"Dynamic stability of a free flight aerospace vehicle is investigated in this paper. Firstly, the slender rocket body is modeled as a classic uniform beam that subjected to constant end rocket thrust. The one-dimensional free-free beam under follower force is established for structural model to discover dynamic stability. Equations of motion of vehicle is derived by applying extended Hamilton's principle for non-conservative systems. Natural frequencies of rocket are determined and critical thrust is obtained by using finite element method. It is noted that, transverse vibrational modes differ by thrust value. Secondly, natural frequencies of non-homogeneous beam are discussed by considering that rocket has different types and number of stages. Numerical results for both cases are represented.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126840957","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208418
Teodor-Viorel Chelaru, Adrian Chelaru, V. Enache
This paper develop a calculus model based on dedicated experiment for an innovative Reaction Control System (RCS) using hybrid rocket engine technology. Our RCS uses several hybrid micro-thrusters with their thrust modulated by a separate control system. For RCS, each of the thrusters is able to burn a few minutes and its thrust is modulated within certain limits by controlling the oxidizer flow. These studies were presented in RAST 2013 and are based on our own experiments performed in Electromecanica Ploiesti. Based on this concept we achieve a calculation of the performances of the RCS and make a comparison between theoretical and experimental results. Conclusions and discussions will be focused on technological possibilities to improve RCS performance and possible areas of application of it.
{"title":"Reaction control system using hybrid micro-thrusters, theoretical and experimental results","authors":"Teodor-Viorel Chelaru, Adrian Chelaru, V. Enache","doi":"10.1109/RAST.2015.7208418","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208418","url":null,"abstract":"This paper develop a calculus model based on dedicated experiment for an innovative Reaction Control System (RCS) using hybrid rocket engine technology. Our RCS uses several hybrid micro-thrusters with their thrust modulated by a separate control system. For RCS, each of the thrusters is able to burn a few minutes and its thrust is modulated within certain limits by controlling the oxidizer flow. These studies were presented in RAST 2013 and are based on our own experiments performed in Electromecanica Ploiesti. Based on this concept we achieve a calculation of the performances of the RCS and make a comparison between theoretical and experimental results. Conclusions and discussions will be focused on technological possibilities to improve RCS performance and possible areas of application of it.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114125075","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208338
B. Akbulut, O. Tekinalp, K. Azgın
A new attitude control actuator, the vibrating mass gyroscope is considered. The actuator transforms the vibratory motion of a single gimbal gyroscope to a positive or negative, fluctuating control torque. The equations of motion for such an actuator are presented. The feasibility of construction of such an actuator is investigated. Possible means of realizing the vibratory motion is proposed.
{"title":"Vibrationally excited satellite attitude actuator: A feasibility study","authors":"B. Akbulut, O. Tekinalp, K. Azgın","doi":"10.1109/RAST.2015.7208338","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208338","url":null,"abstract":"A new attitude control actuator, the vibrating mass gyroscope is considered. The actuator transforms the vibratory motion of a single gimbal gyroscope to a positive or negative, fluctuating control torque. The equations of motion for such an actuator are presented. The feasibility of construction of such an actuator is investigated. Possible means of realizing the vibratory motion is proposed.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132428896","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208397
I. G. Akay, Z. Kaymaz, D. Sibeck, V. Angelopoulos
Since 2011, ARTEMIS spacecraft 1 and 2 take observations in the solar wind and magnetotail as they orbit around the Moon at +/-60 Re. With the state-of-the-art magnetic field and plasma instruments, they perform the first systematic, two-point observations of the mid-to-distant tail and give an opportunity for the scientist to study the detailed structure of the mid-to-distant tail at -60 Re as well as the tail dynamics since the era of ISEE-3 and Wind in 1970s and mid-1990s. In this study, we use magnetic field observations to perform vector mappings of the magnetotail structure in xy-, xz, and yz-planes. We present our preliminary results based on the investigation of four trajectory passes. The one of the example pass we present here corresponds to the IMF orientation in-y direction. Even it is a single pass, we can see the IMF By effect on the orientation of the magnetic field vectors within the magnetotail. Mapping along the trajectory also shows several unexpected tail magnetic field orientations within the central magnetotail which we attribute to the fact that it is a single pass and thus it may reflect the singular, local short term variations occurred in the central tail as the spacecraft moves. We run MHD model, SWMF-BATSRUS, at CCMC for this single pass to see how much temporally the model and observations agree. The results will be discussed in the frame of understanding the magnetotail behavior in response to the IMF By on a temporal scale.
{"title":"Investigating magnetic field structure at moon distance: A single pass example","authors":"I. G. Akay, Z. Kaymaz, D. Sibeck, V. Angelopoulos","doi":"10.1109/RAST.2015.7208397","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208397","url":null,"abstract":"Since 2011, ARTEMIS spacecraft 1 and 2 take observations in the solar wind and magnetotail as they orbit around the Moon at +/-60 Re. With the state-of-the-art magnetic field and plasma instruments, they perform the first systematic, two-point observations of the mid-to-distant tail and give an opportunity for the scientist to study the detailed structure of the mid-to-distant tail at -60 Re as well as the tail dynamics since the era of ISEE-3 and Wind in 1970s and mid-1990s. In this study, we use magnetic field observations to perform vector mappings of the magnetotail structure in xy-, xz, and yz-planes. We present our preliminary results based on the investigation of four trajectory passes. The one of the example pass we present here corresponds to the IMF orientation in-y direction. Even it is a single pass, we can see the IMF By effect on the orientation of the magnetic field vectors within the magnetotail. Mapping along the trajectory also shows several unexpected tail magnetic field orientations within the central magnetotail which we attribute to the fact that it is a single pass and thus it may reflect the singular, local short term variations occurred in the central tail as the spacecraft moves. We run MHD model, SWMF-BATSRUS, at CCMC for this single pass to see how much temporally the model and observations agree. The results will be discussed in the frame of understanding the magnetotail behavior in response to the IMF By on a temporal scale.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129369090","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208421
Yavuz Emre Kamis, M. Çelik
This study examines the phenomenon of electron cyclotron resonance which is utilized in microwave discharge ion thrusters and neutralizers, and the effects of magnetic field topology on plasma and thruster parameters. Various designs from the literature that use permanent magnets to create a static magnetic field are investigated, their magnetic field topologies are solved and compared. ECR regions with respect to different microwave frequencies are plotted. Further study regarding the numerical plasma modeling based on the topology is explained, the numerical technique behind is described.
{"title":"Study of the effects of the magnetic field topology on the design of a prototype ECR microwave ion thruster and neutralizer","authors":"Yavuz Emre Kamis, M. Çelik","doi":"10.1109/RAST.2015.7208421","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208421","url":null,"abstract":"This study examines the phenomenon of electron cyclotron resonance which is utilized in microwave discharge ion thrusters and neutralizers, and the effects of magnetic field topology on plasma and thruster parameters. Various designs from the literature that use permanent magnets to create a static magnetic field are investigated, their magnetic field topologies are solved and compared. ECR regions with respect to different microwave frequencies are plotted. Further study regarding the numerical plasma modeling based on the topology is explained, the numerical technique behind is described.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131596897","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208385
Selin Arabaci, Elif Dirgin
This paper discusses and outlines correlation of thermal mathematical model of qualification model of Gokturk-2 satellite, which is an Earth Observation satellite with electro-optical payload, with the thermal balance test results. The thermal balance test environment, test instrumentation and test set-up are explained. The orbit altitude for the satellite is 680 km. A companion paper describes the thermal and geometrical mathematical modeling and analysis steps of a similar satellite [1]. Gokturk-2 is a hexagonal shaped satellite with aluminum honeycomb panels. It is covered with MLI and has seven SSM radiators. Thermica v.3.2.20.1 is used as simulator for the test environment and for calculation of radiative couplings [2]. In addition, SINDA/G is used as solver for thermal analysis.
{"title":"Thermal mathematical model correlation of an earth observation satellite","authors":"Selin Arabaci, Elif Dirgin","doi":"10.1109/RAST.2015.7208385","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208385","url":null,"abstract":"This paper discusses and outlines correlation of thermal mathematical model of qualification model of Gokturk-2 satellite, which is an Earth Observation satellite with electro-optical payload, with the thermal balance test results. The thermal balance test environment, test instrumentation and test set-up are explained. The orbit altitude for the satellite is 680 km. A companion paper describes the thermal and geometrical mathematical modeling and analysis steps of a similar satellite [1]. Gokturk-2 is a hexagonal shaped satellite with aluminum honeycomb panels. It is covered with MLI and has seven SSM radiators. Thermica v.3.2.20.1 is used as simulator for the test environment and for calculation of radiative couplings [2]. In addition, SINDA/G is used as solver for thermal analysis.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133490303","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208443
T. Somova
We present simple method for digital attitude control of the land-survey mini-satellites, algorithms and software for imitation and animation of their spatial orbital motion.
{"title":"Digital and pulse-width attitude control, imitation and animation of land-survey mini-satellite motion","authors":"T. Somova","doi":"10.1109/RAST.2015.7208443","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208443","url":null,"abstract":"We present simple method for digital attitude control of the land-survey mini-satellites, algorithms and software for imitation and animation of their spatial orbital motion.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129687791","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 : 2015-06-16DOI: 10.1109/RAST.2015.7208434
A. Kozlov, A. Golovan, A. Nikulin, A. Cepe, V. Chemodanov
Multi-antenna GPS attitude determination is considered as an alternative source of orientation for future satellites. Conventional attitude algorithms of this kind require antenna geometry to be fixed and known. However, in several situations this might be not the case. Present work aims to discern different situations that arise when GPS antenna array structure is not rigid. In most general case, arbitrary antenna displacements are not observable; therefore attitude can be resolved only within the ambiguity caused by displacements. Nevertheless, if antenna array geometry deformation is somehow restricted, there exist observable combinations. We also analyze if inertial angular rate sensors (gyroscopes) can help to discern between antenna structure deformation and attitude change. In this case it is essentially important if deformations are constant or how they vary over time.
{"title":"GPS attitude determination under antenna array geometry deformation","authors":"A. Kozlov, A. Golovan, A. Nikulin, A. Cepe, V. Chemodanov","doi":"10.1109/RAST.2015.7208434","DOIUrl":"https://doi.org/10.1109/RAST.2015.7208434","url":null,"abstract":"Multi-antenna GPS attitude determination is considered as an alternative source of orientation for future satellites. Conventional attitude algorithms of this kind require antenna geometry to be fixed and known. However, in several situations this might be not the case. Present work aims to discern different situations that arise when GPS antenna array structure is not rigid. In most general case, arbitrary antenna displacements are not observable; therefore attitude can be resolved only within the ambiguity caused by displacements. Nevertheless, if antenna array geometry deformation is somehow restricted, there exist observable combinations. We also analyze if inertial angular rate sensors (gyroscopes) can help to discern between antenna structure deformation and attitude change. In this case it is essentially important if deformations are constant or how they vary over time.","PeriodicalId":282476,"journal":{"name":"2015 7th International Conference on Recent Advances in Space Technologies (RAST)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124926418","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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