Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805925
K. Natarajan, D. Walters, B. Maglaris
We address the problem of designing a circuit-switched network for voice communications operating in a military environment. The circuit-switched network design problem may be briefly stated as: given the topology, route tables and control discipline, end-to-end offered traffic and performance requirements, determine trunk group sizes such that the requirements are satisfied. One of the key requirements of a design is that the network be survivable, where survivability is based on different destruction scenario conditions. Our objective is to guarantee an acceptable level of performance for every node pair and under each of the different anticipated damage scenarios. The main contributions of our present work are the development of approaches for designing networks that simultaneously satisfy performance requirements for different destruction scenarios. We describe the architecture of a survivable, circuit-switched network. The key characteristics of the survivable network design problem are highlighted and differences with respect to classical trunk sizing problem are pointed out. An important aspect of our work is that the sizing is based on the logical topology of the network rather than its trunk group topology. One design approach, which we have used successfully, is presented in detail.
{"title":"Design of Survivable Circuit-Switched Communication Networks","authors":"K. Natarajan, D. Walters, B. Maglaris","doi":"10.1109/MILCOM.1982.4805925","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805925","url":null,"abstract":"We address the problem of designing a circuit-switched network for voice communications operating in a military environment. The circuit-switched network design problem may be briefly stated as: given the topology, route tables and control discipline, end-to-end offered traffic and performance requirements, determine trunk group sizes such that the requirements are satisfied. One of the key requirements of a design is that the network be survivable, where survivability is based on different destruction scenario conditions. Our objective is to guarantee an acceptable level of performance for every node pair and under each of the different anticipated damage scenarios. The main contributions of our present work are the development of approaches for designing networks that simultaneously satisfy performance requirements for different destruction scenarios. We describe the architecture of a survivable, circuit-switched network. The key characteristics of the survivable network design problem are highlighted and differences with respect to classical trunk sizing problem are pointed out. An important aspect of our work is that the sizing is based on the logical topology of the network rather than its trunk group topology. One design approach, which we have used successfully, is presented in detail.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"30 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123587647","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805921
M. Beeler
Digital communications on a shared, random access channel benefits from good codes to synchronize and to multiplex the data. Such codes have high autocorrelation and low crosscorrelation, respectively. Finding long binary sequences with these properties is difficult, and generally involves significant brute force searching. A custom computing engine performs such a search much faster than other approaches, and a custom VLSI chip is a practical means of constructing such an engine. The practical advantages and costs of this approach are discussed.
{"title":"Finding Good Signalling Codes with Custom VLSI","authors":"M. Beeler","doi":"10.1109/MILCOM.1982.4805921","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805921","url":null,"abstract":"Digital communications on a shared, random access channel benefits from good codes to synchronize and to multiplex the data. Such codes have high autocorrelation and low crosscorrelation, respectively. Finding long binary sequences with these properties is difficult, and generally involves significant brute force searching. A custom computing engine performs such a search much faster than other approaches, and a custom VLSI chip is a practical means of constructing such an engine. The practical advantages and costs of this approach are discussed.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122697980","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4806025
J. Bartow
In 1981 CECOM placed four contracts for the exploratory development of ECCM techniques which are to be considered for use in a new digital microwave radio development. A spread spectrum modem is under development which will operate in the 4.4 to 5.0 GHz band. The modem will also be designed to operate, with minor changes, in the 14.4 to 15.35 GHz range. The modulation techniuqe selected is offset quadriphase shift keying. A hybrid direct sequence/frequency hopping system is being designed. The data rates at which the modems are expected to operate are related to various TRI-TAC and DCS multiplexers. Input data rates will vary from 72 kbps to 4.608 in the 4.4-5.0 GHz band and from 72 kbps to 18.720 Mbps in the 14.4-15.35 GHz band. The modulation and frequency translation schemes will be discussed. A steerable null antenna system will be designed for both RF bands and fabricated for C-band. The objective of this antenna is to discriminate against unwanted signals arriving in its side lobes and in the main beam. Among the requirements and constraints which will affect the antenna design are the need for duplex operation, the necessity for installation of the antenna on a 100 foot tactical mast, and the requirement to operate with high output power levels. A coding equipment development is underway which will result in the fabrication of an error correction technique to correct random errors and bursts of errors in the modem output.
{"title":"Digital Microwave Radio Program","authors":"J. Bartow","doi":"10.1109/MILCOM.1982.4806025","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806025","url":null,"abstract":"In 1981 CECOM placed four contracts for the exploratory development of ECCM techniques which are to be considered for use in a new digital microwave radio development. A spread spectrum modem is under development which will operate in the 4.4 to 5.0 GHz band. The modem will also be designed to operate, with minor changes, in the 14.4 to 15.35 GHz range. The modulation techniuqe selected is offset quadriphase shift keying. A hybrid direct sequence/frequency hopping system is being designed. The data rates at which the modems are expected to operate are related to various TRI-TAC and DCS multiplexers. Input data rates will vary from 72 kbps to 4.608 in the 4.4-5.0 GHz band and from 72 kbps to 18.720 Mbps in the 14.4-15.35 GHz band. The modulation and frequency translation schemes will be discussed. A steerable null antenna system will be designed for both RF bands and fabricated for C-band. The objective of this antenna is to discriminate against unwanted signals arriving in its side lobes and in the main beam. Among the requirements and constraints which will affect the antenna design are the need for duplex operation, the necessity for installation of the antenna on a 100 foot tactical mast, and the requirement to operate with high output power levels. A coding equipment development is underway which will result in the fabrication of an error correction technique to correct random errors and bursts of errors in the modem output.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117074477","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805934
R. Lunayach, Sunir Kochhar
In this paper performance of a spread spectrum system with a large number of network terminals and a small number of network control terminals is addressed. Network control terminals carry out most functions relating acquisitions, synchronization, control and aid network terminals. Network response times are calculated for various aiding stratagies and the conditions for a stable network operation are derived. Analytical results are verified with the help of simulations carried out using simulation language SLAM.
{"title":"Network Response Times of a Spread Spectrum System with Large Number of Network Terminals and Central Control","authors":"R. Lunayach, Sunir Kochhar","doi":"10.1109/MILCOM.1982.4805934","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805934","url":null,"abstract":"In this paper performance of a spread spectrum system with a large number of network terminals and a small number of network control terminals is addressed. Network control terminals carry out most functions relating acquisitions, synchronization, control and aid network terminals. Network response times are calculated for various aiding stratagies and the conditions for a stable network operation are derived. Analytical results are verified with the help of simulations carried out using simulation language SLAM.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114822343","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805980
Michael D. Kennedy
While it appears desirable to allow spread spectrum communications in the civilian environment, a number of questions must be answered before its introduction. How will the Commission authorize spread spectrum, with its large radio frequency bandwidth, in a spectrum that has largely been divided into many narrow bands? How can the Commission, with the aid of its licensees, monitor spread spectrum transmissions and enforce both technical and operational regulations? What will be the extent of interference between spread spectrum and narrow band-signals? It appears that these questions can be answered, and the problems they typify mitigated, by careful management on the part of the Commission.
{"title":"Regulatory Aspects of Spread Spectrum Communications","authors":"Michael D. Kennedy","doi":"10.1109/MILCOM.1982.4805980","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805980","url":null,"abstract":"While it appears desirable to allow spread spectrum communications in the civilian environment, a number of questions must be answered before its introduction. How will the Commission authorize spread spectrum, with its large radio frequency bandwidth, in a spectrum that has largely been divided into many narrow bands? How can the Commission, with the aid of its licensees, monitor spread spectrum transmissions and enforce both technical and operational regulations? What will be the extent of interference between spread spectrum and narrow band-signals? It appears that these questions can be answered, and the problems they typify mitigated, by careful management on the part of the Commission.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128038948","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4806016
F. Bond
The current MILSATCOM assets are reviewed and assessed with regard to the ultimate military potential of the satellite transmission medium. Examples are presented showing why the future use of satellite communication will be impacted by geopolitical trends and re-directions in national policy. The key military issue is surviving and enduring communication over the entire spectrum of conflict levels and the need for a balanced defense against all possible threats. The importance of the network approach involving diverse transmission media is stressed. This in turn requires a more determined effort for achieving improved interoperability with the use of transmission standards. The proposed course for future MILSATCOM systems is based on: evolution toward higher frequencies, internetting of satellite and ground links, ability to reconfigure satcom assets, and more sophisticated access and network control. Also addressed is the suggested policy for exploiting the extensive commercial satcom facilities and the need for closer coordination with the organizations planning the future major terrestrial communication systems.
{"title":"Long Range MILSATCOM Architecture","authors":"F. Bond","doi":"10.1109/MILCOM.1982.4806016","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806016","url":null,"abstract":"The current MILSATCOM assets are reviewed and assessed with regard to the ultimate military potential of the satellite transmission medium. Examples are presented showing why the future use of satellite communication will be impacted by geopolitical trends and re-directions in national policy. The key military issue is surviving and enduring communication over the entire spectrum of conflict levels and the need for a balanced defense against all possible threats. The importance of the network approach involving diverse transmission media is stressed. This in turn requires a more determined effort for achieving improved interoperability with the use of transmission standards. The proposed course for future MILSATCOM systems is based on: evolution toward higher frequencies, internetting of satellite and ground links, ability to reconfigure satcom assets, and more sophisticated access and network control. Also addressed is the suggested policy for exploiting the extensive commercial satcom facilities and the need for closer coordination with the organizations planning the future major terrestrial communication systems.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127712624","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805912
A. Budreau, R. T. Webster
The feasibility of using a surface acoustic wave device with switchable, closely spaced taps as a frequency hopping filter has been demonstrated. The test devices operate at 200-300 MHz for a Texas Instruments lithium niobate wire-bonded filter, (ref. 1) and 125-135 MHz for a United Technologies Research Center monolithic gallium arsenide (GaAs) device. (ref. 2) Future work is planned to develop GaAs monolithic versions at 0.5 and 1.0 GHz. These are, in fact, programmable transversal filters. They perform a variety of time domain functions such as matched filtering (asynchronous correlation), and they operate as variable frequency domain devices as well. In the latter mode, variable width passbands and notch rejection, as well as tunable bandpass, are achievable. Thus, adaptive operation in an electronic warfare scenario is a possible application. A planned use is in the Air Force's Integrated Communications, Navigation, Identification Avionics (ICNIA) program.
{"title":"Frequency-Hopping Filters and Programmable Matched Filters for Spread-Spectrum Systems","authors":"A. Budreau, R. T. Webster","doi":"10.1109/MILCOM.1982.4805912","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805912","url":null,"abstract":"The feasibility of using a surface acoustic wave device with switchable, closely spaced taps as a frequency hopping filter has been demonstrated. The test devices operate at 200-300 MHz for a Texas Instruments lithium niobate wire-bonded filter, (ref. 1) and 125-135 MHz for a United Technologies Research Center monolithic gallium arsenide (GaAs) device. (ref. 2) Future work is planned to develop GaAs monolithic versions at 0.5 and 1.0 GHz. These are, in fact, programmable transversal filters. They perform a variety of time domain functions such as matched filtering (asynchronous correlation), and they operate as variable frequency domain devices as well. In the latter mode, variable width passbands and notch rejection, as well as tunable bandpass, are achievable. Thus, adaptive operation in an electronic warfare scenario is a possible application. A planned use is in the Air Force's Integrated Communications, Navigation, Identification Avionics (ICNIA) program.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130011707","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805970
P. Anderson, F. Hsu, M. Sandler
Reliable digital communication over long-haul HF circuits, at rates above 1 bps/Hz, is possible if an adaptive equalizer technique is used which will successfully follow the fading characteristics of the time-dispersive channel. This paper summarizes an investigation of this tracking problem which led to the selection of a square-root Kalman algorithm to update the coefficients of a decision feedback equalizer (DFE). The design and implementation of a new HF modem utilizing the Kalman DFE in conjunction with a continuous GO BACK N ARQ strategy is described. Results of performance tests at data rates from 2400 to 9600 bps using a 3 kHz real-time HF channel simulator are presented. Both low error rate and high throughput are achieved using the combined adaptive channel equalization and ARQ techniques. Preliminary results from tests over a long-haul live link are also reported.
{"title":"A New Adaptive Modem for Long Haul HF Digital Communications at Data Rates Greater than 1 bps/Hz","authors":"P. Anderson, F. Hsu, M. Sandler","doi":"10.1109/MILCOM.1982.4805970","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805970","url":null,"abstract":"Reliable digital communication over long-haul HF circuits, at rates above 1 bps/Hz, is possible if an adaptive equalizer technique is used which will successfully follow the fading characteristics of the time-dispersive channel. This paper summarizes an investigation of this tracking problem which led to the selection of a square-root Kalman algorithm to update the coefficients of a decision feedback equalizer (DFE). The design and implementation of a new HF modem utilizing the Kalman DFE in conjunction with a continuous GO BACK N ARQ strategy is described. Results of performance tests at data rates from 2400 to 9600 bps using a 3 kHz real-time HF channel simulator are presented. Both low error rate and high throughput are achieved using the combined adaptive channel equalization and ARQ techniques. Preliminary results from tests over a long-haul live link are also reported.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131216257","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805904
C. Weber, G. Huth
An enumeration of the types of interference pertinent to direct-sequence systems is given. The candidates are categorized as narrowband or wideband. The performance of direct-sequence (DS) systems in the presence of a variety of types of interference is also presented. When the jammer has a choice of parameters, the optimal value is then determined.
{"title":"The Performance of Direct-Sequence Systems in the Presence of Jammers","authors":"C. Weber, G. Huth","doi":"10.1109/MILCOM.1982.4805904","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805904","url":null,"abstract":"An enumeration of the types of interference pertinent to direct-sequence systems is given. The candidates are categorized as narrowband or wideband. The performance of direct-sequence (DS) systems in the presence of a variety of types of interference is also presented. When the jammer has a choice of parameters, the optimal value is then determined.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121985629","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4806020
J. Pan
Recent progress of GaAs Monolithic Microwave Integrated Circuit (MMIC) and Gb/s logic has established a solid foundation for many future system applications. Systems benefiting from these advances include phased/adaptive arrays, MILSATCOM, Television Receive-Only (TVRO) receiver, Electronic Warfare (EW), instrumentation and radar. This paper presents various MMIC technologies and tradeoffs of materials (crystal growths, orientations, material properties, characterization techniques, etc.), processes (ion-implantation, Molecular Beam Epitaxy, Vapor Phase Epitaxy, Liquid Phase Epitaxy), and circuit fabrication via hole, air bridge, active matching, etc. The performance of the presently achieved SHF/EHF MMIC's are summarized. Technical problems, possible solutions, and future trends of MMIC design and fabrication (impedance matching methods, bias, low noise techniques, medium power IC's, EHF circuits, filters, isolators, packaging techniques, etc.) are also described.
{"title":"Monolithic Microwave IC Technologies and System Applications","authors":"J. Pan","doi":"10.1109/MILCOM.1982.4806020","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806020","url":null,"abstract":"Recent progress of GaAs Monolithic Microwave Integrated Circuit (MMIC) and Gb/s logic has established a solid foundation for many future system applications. Systems benefiting from these advances include phased/adaptive arrays, MILSATCOM, Television Receive-Only (TVRO) receiver, Electronic Warfare (EW), instrumentation and radar. This paper presents various MMIC technologies and tradeoffs of materials (crystal growths, orientations, material properties, characterization techniques, etc.), processes (ion-implantation, Molecular Beam Epitaxy, Vapor Phase Epitaxy, Liquid Phase Epitaxy), and circuit fabrication via hole, air bridge, active matching, etc. The performance of the presently achieved SHF/EHF MMIC's are summarized. Technical problems, possible solutions, and future trends of MMIC design and fabrication (impedance matching methods, bias, low noise techniques, medium power IC's, EHF circuits, filters, isolators, packaging techniques, etc.) are also described.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122267751","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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