Pub Date : 1990-02-04DOI: 10.1109/AERO.1990.109092
A. Jackson, E. Jackson
The authors analyse changes in US and Japanese semiconductor industry. They consider how changes in the industry have affected, and will continue to affect, aerospace design engineers. The emphasis is on the advanced microelectronic products. Attention is focused on the high reliability and extended temperature range devices as well as on the full military specification and radiation-hardened (rad-hard) parts. It is found that, in 1989, Japanese firms made almost 50% of worldwide semiconductor sales, compared to less than 40% for all North American companies. Furthermore, in 1990, 90% of all dynamic random access memory chips were made by Japanese firms. The Japanese are also ahead of the US in some of the critical microelectronic R&D areas such as GaAs rad-hard devices.<>
{"title":"US leadership loss in microelectronics could seriously impact aerospace applications","authors":"A. Jackson, E. Jackson","doi":"10.1109/AERO.1990.109092","DOIUrl":"https://doi.org/10.1109/AERO.1990.109092","url":null,"abstract":"The authors analyse changes in US and Japanese semiconductor industry. They consider how changes in the industry have affected, and will continue to affect, aerospace design engineers. The emphasis is on the advanced microelectronic products. Attention is focused on the high reliability and extended temperature range devices as well as on the full military specification and radiation-hardened (rad-hard) parts. It is found that, in 1989, Japanese firms made almost 50% of worldwide semiconductor sales, compared to less than 40% for all North American companies. Furthermore, in 1990, 90% of all dynamic random access memory chips were made by Japanese firms. The Japanese are also ahead of the US in some of the critical microelectronic R&D areas such as GaAs rad-hard devices.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124386345","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 : 1990-02-04DOI: 10.1109/AERO.1990.109088
W. Schwarzmann
A data-handling and control concept which uses a data bus to integrate digital data in satellites is presented. Onboard sensor data are processed to generate messages that utilize a data bus to provide flexible interconnections with other onboard processors and, through a communications network, to other satellites and the ground. A design that can be tailored to meet the requirements of different satellites is addressed. Design options are analyzed and summarized. Standard bus interface units are available to adapt different processors permitting easy integration into the satellite system. A MIL-STD-1750A processor that meets US DOD requirements supported by software tools permitting the use of Ada has been developed.<>
{"title":"A flexible data handling concept","authors":"W. Schwarzmann","doi":"10.1109/AERO.1990.109088","DOIUrl":"https://doi.org/10.1109/AERO.1990.109088","url":null,"abstract":"A data-handling and control concept which uses a data bus to integrate digital data in satellites is presented. Onboard sensor data are processed to generate messages that utilize a data bus to provide flexible interconnections with other onboard processors and, through a communications network, to other satellites and the ground. A design that can be tailored to meet the requirements of different satellites is addressed. Design options are analyzed and summarized. Standard bus interface units are available to adapt different processors permitting easy integration into the satellite system. A MIL-STD-1750A processor that meets US DOD requirements supported by software tools permitting the use of Ada has been developed.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133846147","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 : 1990-02-04DOI: 10.1109/AERO.1990.109086
W.C. Wenjen
The implementation considerations for Ada to Structured Query Language (SQL) interfaces in command, control, communications, and intelligence (C/sup 3/I) applications are described. In particular, four aspects of these interfaces are considered: program portability, query optimization, null value treatment, and host variable semantics. Three different proposals for a standard Ada-to-SQL interface are examined with respect to these criteria: the ANSI proposal, the Institute for Defense Analyses (IDA) Ada/SQL approach, and the Software Engineering Institute (SEI) SQL Ada module extension (SAME) technique. The SAME binding was found to be most appropriate for C3I systems due to its support for separate application and database development, integrated support for null-values, type conversion, and error handling. Alternatively, the ANSI interface could also be used by creating a layer of interfacing programs which are used by the application program.<>
{"title":"Ada to SQL interfaces for C/sup 3/I applications","authors":"W.C. Wenjen","doi":"10.1109/AERO.1990.109086","DOIUrl":"https://doi.org/10.1109/AERO.1990.109086","url":null,"abstract":"The implementation considerations for Ada to Structured Query Language (SQL) interfaces in command, control, communications, and intelligence (C/sup 3/I) applications are described. In particular, four aspects of these interfaces are considered: program portability, query optimization, null value treatment, and host variable semantics. Three different proposals for a standard Ada-to-SQL interface are examined with respect to these criteria: the ANSI proposal, the Institute for Defense Analyses (IDA) Ada/SQL approach, and the Software Engineering Institute (SEI) SQL Ada module extension (SAME) technique. The SAME binding was found to be most appropriate for C3I systems due to its support for separate application and database development, integrated support for null-values, type conversion, and error handling. Alternatively, the ANSI interface could also be used by creating a layer of interfacing programs which are used by the application program.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"694 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116961812","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 : 1990-02-04DOI: 10.1109/AERO.1990.109071
L. Mueller, S. Lazar, N. Golden
An overview of the GPS (global positioning system) is provided. Details are presented on the navigation message that is utilized by GPS user equipment (UE) to provide the user his position, time, and velocity. In order to reduce the adverse impact on GPS users of hosting a new software (S/W) release (OR 5.10) on the operational computer at the Master Control Station System, a multiphased test plan was developed to thoroughly test the S/W end-to-end prior to space vehicle uploads. Test objectives and results are provided for Phase-I test. The Phase-I report has been completed with test results, recommendations, and conclusions. One of the recommendations centered on improving the test configuration such that correlation of upload and UE data could be performed in near real time. A series of options for such a system testbed (STB) were evaluated. For each option, the pros, cons, and rough order of magnitude costs were identified. A potential STB configuration was recommended. It is concluded that no evidence exists to suggest that OR 5.10 will adversely affect the GPS user community with uploads as old as 11 d.<>
{"title":"Validating GPS software and implications for the future","authors":"L. Mueller, S. Lazar, N. Golden","doi":"10.1109/AERO.1990.109071","DOIUrl":"https://doi.org/10.1109/AERO.1990.109071","url":null,"abstract":"An overview of the GPS (global positioning system) is provided. Details are presented on the navigation message that is utilized by GPS user equipment (UE) to provide the user his position, time, and velocity. In order to reduce the adverse impact on GPS users of hosting a new software (S/W) release (OR 5.10) on the operational computer at the Master Control Station System, a multiphased test plan was developed to thoroughly test the S/W end-to-end prior to space vehicle uploads. Test objectives and results are provided for Phase-I test. The Phase-I report has been completed with test results, recommendations, and conclusions. One of the recommendations centered on improving the test configuration such that correlation of upload and UE data could be performed in near real time. A series of options for such a system testbed (STB) were evaluated. For each option, the pros, cons, and rough order of magnitude costs were identified. A potential STB configuration was recommended. It is concluded that no evidence exists to suggest that OR 5.10 will adversely affect the GPS user community with uploads as old as 11 d.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131258856","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 : 1990-02-04DOI: 10.1109/AERO.1990.109069
C. S. Miller
The problem of the SDI (strategic defense initiative) onboard battle management processing is addressed. A brief overview of the general requirements for wartime space processing is presented, and the processing requirements which are specific to the battle management problem are discussed. Processor architecture and implementation using 05- mu m very high speed integrated circuit II (VHSIC II) superchip monolithic wafer-scale integration are considered. The sizing for both the VHSIC II and conventional LSI implementations is given. It is concluded that a spaceborne battle management processor capable of the throughput rate needed for the difficult SDI midcourse war scenario is feasible using advanced technology and an architecture tailored to the specifics of the problem. The critical effect of power consumption on spacecraft cost appears to militate against the use of conventional processor architectures and LSI implementation. Demanding specifications for survivability and reliability can be met by the use of a hierarchical fault-tolerant architecture based on the superchips. The battle management processor design, capable of over a billion operations per second, has a volume of 2.3 ft/sup 3/, a weight of 125 lb, and a power consumption of 1500 W. An LSI version with the same throughput would be significantly larger, heavier, and more power consumptive. The use of superchip or equivalent technology appears to be the key to achieving both the required high throughput and the 10-yr on-orbit lifetime.<>
{"title":"Battle management onboard processing for SDI","authors":"C. S. Miller","doi":"10.1109/AERO.1990.109069","DOIUrl":"https://doi.org/10.1109/AERO.1990.109069","url":null,"abstract":"The problem of the SDI (strategic defense initiative) onboard battle management processing is addressed. A brief overview of the general requirements for wartime space processing is presented, and the processing requirements which are specific to the battle management problem are discussed. Processor architecture and implementation using 05- mu m very high speed integrated circuit II (VHSIC II) superchip monolithic wafer-scale integration are considered. The sizing for both the VHSIC II and conventional LSI implementations is given. It is concluded that a spaceborne battle management processor capable of the throughput rate needed for the difficult SDI midcourse war scenario is feasible using advanced technology and an architecture tailored to the specifics of the problem. The critical effect of power consumption on spacecraft cost appears to militate against the use of conventional processor architectures and LSI implementation. Demanding specifications for survivability and reliability can be met by the use of a hierarchical fault-tolerant architecture based on the superchips. The battle management processor design, capable of over a billion operations per second, has a volume of 2.3 ft/sup 3/, a weight of 125 lb, and a power consumption of 1500 W. An LSI version with the same throughput would be significantly larger, heavier, and more power consumptive. The use of superchip or equivalent technology appears to be the key to achieving both the required high throughput and the 10-yr on-orbit lifetime.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134361801","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 : 1990-02-04DOI: 10.1109/AERO.1990.109081
W.-C. Peng, C. Yang, C. Lichtenberg
A standalone pressure transducer (SAPT) is a credit-card-sized smart pressure sensor inserted between the tile and the aluminum skin of a Space Shuttle. Reliably initiating the SAPT units via RF signals in a prelaunch environment is a challenging problem. Multiple-source interference may exist if more than one GSE (ground support equipment) antenna is turned on at the same time to meet the simultaneity requirement of 10 ms. Multipath interference due to reflections from the orbiter, external tank, solid rocket boosters, tail service masts, etc. further complicates the problem. The authors address the coverage and the multipath/multiple-source interference problem. A polygon model for orbiter, external tank, solid rocket booster, and tail service masts is used to simulate the prelaunch environment. Geometric optics is then applied to identify the coverage areas and the areas which are vulnerable to multipath and/or multiple-source interference. Simulation results show that the underside areas of an orbiter have incidence angles exceeding 80 degrees . For multipath interference, both sides of the cargo bay areas are found to be vulnerable to a worst-case multipath loss exceeding 20 dB. Multiple-source interference areas are also identified. Mitigation methods for the coverage and interference problem are described. It is shown that multiple-source interference can be eliminated (or controlled) using the time-division-multiplexing method or the time-stamp approach.<>
{"title":"SAPT units turn-on in an interference-dominant environment","authors":"W.-C. Peng, C. Yang, C. Lichtenberg","doi":"10.1109/AERO.1990.109081","DOIUrl":"https://doi.org/10.1109/AERO.1990.109081","url":null,"abstract":"A standalone pressure transducer (SAPT) is a credit-card-sized smart pressure sensor inserted between the tile and the aluminum skin of a Space Shuttle. Reliably initiating the SAPT units via RF signals in a prelaunch environment is a challenging problem. Multiple-source interference may exist if more than one GSE (ground support equipment) antenna is turned on at the same time to meet the simultaneity requirement of 10 ms. Multipath interference due to reflections from the orbiter, external tank, solid rocket boosters, tail service masts, etc. further complicates the problem. The authors address the coverage and the multipath/multiple-source interference problem. A polygon model for orbiter, external tank, solid rocket booster, and tail service masts is used to simulate the prelaunch environment. Geometric optics is then applied to identify the coverage areas and the areas which are vulnerable to multipath and/or multiple-source interference. Simulation results show that the underside areas of an orbiter have incidence angles exceeding 80 degrees . For multipath interference, both sides of the cargo bay areas are found to be vulnerable to a worst-case multipath loss exceeding 20 dB. Multiple-source interference areas are also identified. Mitigation methods for the coverage and interference problem are described. It is shown that multiple-source interference can be eliminated (or controlled) using the time-division-multiplexing method or the time-stamp approach.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124191387","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 : 1990-02-04DOI: 10.1109/AERO.1990.109093
H.S.C. Wang
To provide generic design guidelines for volute antenna elements over a wide range of parameters, a theoretical formulation and algorithm for computing the antenna radiation field have been developed. From these computed field values, the antenna directivity, 3-dB beamwidth, axial ratio, and front/back ratio can be evaluated for the purpose of design tradeoff considerations. The technical approach used is to compute the radiation fields for the helical wires and the straight-end connecting wires, based on a sinusoidal current distribution model along each of the four filaments or wires of the volute. Using axial length as a running variable, a complete tradeoff for the case of the half-turn, half-wavelength volute to meet certain special requirements was considered as an example for design analysis.<>
{"title":"Theoretical design and predictions of volute antenna performance","authors":"H.S.C. Wang","doi":"10.1109/AERO.1990.109093","DOIUrl":"https://doi.org/10.1109/AERO.1990.109093","url":null,"abstract":"To provide generic design guidelines for volute antenna elements over a wide range of parameters, a theoretical formulation and algorithm for computing the antenna radiation field have been developed. From these computed field values, the antenna directivity, 3-dB beamwidth, axial ratio, and front/back ratio can be evaluated for the purpose of design tradeoff considerations. The technical approach used is to compute the radiation fields for the helical wires and the straight-end connecting wires, based on a sinusoidal current distribution model along each of the four filaments or wires of the volute. Using axial length as a running variable, a complete tradeoff for the case of the half-turn, half-wavelength volute to meet certain special requirements was considered as an example for design analysis.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131588814","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 : 1990-02-04DOI: 10.1109/AERO.1990.109083
W. C. Jackson, M.E. McDowell
The authors review the traditional simulated annealing algorithm, presenting physical analogies of the process and a formal statement of the algorithm, and propose a modification to the classical simulated annealing process through the use of dynamic perturbation functions. This modification is shown to yield a significant improvement in performance for the 50-city traveling salesman problem. The authors suggest a methodology for mapping aerospace problems into optimization problems to be solved by simulated annealing and demonstrate this methodology on three sample aerospace engineering problems: air traffic control, aircraft mission planning, and signal path switching.<>
{"title":"Simulated annealing with dynamic perturbations: a methodology for optimization","authors":"W. C. Jackson, M.E. McDowell","doi":"10.1109/AERO.1990.109083","DOIUrl":"https://doi.org/10.1109/AERO.1990.109083","url":null,"abstract":"The authors review the traditional simulated annealing algorithm, presenting physical analogies of the process and a formal statement of the algorithm, and propose a modification to the classical simulated annealing process through the use of dynamic perturbation functions. This modification is shown to yield a significant improvement in performance for the 50-city traveling salesman problem. The authors suggest a methodology for mapping aerospace problems into optimization problems to be solved by simulated annealing and demonstrate this methodology on three sample aerospace engineering problems: air traffic control, aircraft mission planning, and signal path switching.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125202950","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 : 1990-02-04DOI: 10.1109/AERO.1990.109085
D. Quincey, J. Smith
Some of the aspects of the communications protocol stacks that have been recommended for the packet communications services for the Space Station Freedom Program are discussed. Particular attention is given to the protocol stacks that support the two space-to-ground packet communications services, the path and internet services. The protocol stacks of the subnetworks and gateways that connect onboard and ground user applications are discussed. Standards developed by the Consultative Committee for Space Data Systems are used to implement the data link and physical layer function for the protocol stacks of the space link subnet which joins the onboard and ground networks.<>
{"title":"Communications protocol stacks for the Space Station Freedom","authors":"D. Quincey, J. Smith","doi":"10.1109/AERO.1990.109085","DOIUrl":"https://doi.org/10.1109/AERO.1990.109085","url":null,"abstract":"Some of the aspects of the communications protocol stacks that have been recommended for the packet communications services for the Space Station Freedom Program are discussed. Particular attention is given to the protocol stacks that support the two space-to-ground packet communications services, the path and internet services. The protocol stacks of the subnetworks and gateways that connect onboard and ground user applications are discussed. Standards developed by the Consultative Committee for Space Data Systems are used to implement the data link and physical layer function for the protocol stacks of the space link subnet which joins the onboard and ground networks.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130356043","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 : 1990-02-04DOI: 10.1109/AERO.1990.109089
R.R. Roy
A continuous-time Markov chain model of a token ring network with each node having a finite buffer is presented. A model is developed to analyze the token ring network by considering the exponential distribution of message length and token transmission time. Throughput, delay, probability of blocking, and throughput-delay tradeoffs have been derived. A comparative evaluation of the performance of the token ring network with the mathematical models stated by W. Bux (1981) is also presented. It is pointed out that the proposed model is so general that it can be extended to analyze the interconnected token ring local area networks using the window flow control mechanism for ground and spaceborne systems.<>
{"title":"Continuous time Markov chain model for token ring local area network","authors":"R.R. Roy","doi":"10.1109/AERO.1990.109089","DOIUrl":"https://doi.org/10.1109/AERO.1990.109089","url":null,"abstract":"A continuous-time Markov chain model of a token ring network with each node having a finite buffer is presented. A model is developed to analyze the token ring network by considering the exponential distribution of message length and token transmission time. Throughput, delay, probability of blocking, and throughput-delay tradeoffs have been derived. A comparative evaluation of the performance of the token ring network with the mathematical models stated by W. Bux (1981) is also presented. It is pointed out that the proposed model is so general that it can be extended to analyze the interconnected token ring local area networks using the window flow control mechanism for ground and spaceborne systems.<<ETX>>","PeriodicalId":141316,"journal":{"name":"IEEE Conference on Aerospace Applications","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125816206","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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