Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4805914
W. Stark
The error probability for coherent frequency-hopped spread-spectrum communications in the presence of partial-band jamming is investigated. We consider both tone and noise jamming and calculate symbol error probabilities for BPSK, QPSK, and M-ary orthogonal signal sets. The error probability with coding is found and tradeoffs between various coding strategies are determined for the worst case partial-band jammer.
{"title":"Coding for Coherent Frequency-Hopped Spread-Spectrum Communication in the Presence of Jamming","authors":"W. Stark","doi":"10.1109/MILCOM.1982.4805914","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805914","url":null,"abstract":"The error probability for coherent frequency-hopped spread-spectrum communications in the presence of partial-band jamming is investigated. We consider both tone and noise jamming and calculate symbol error probabilities for BPSK, QPSK, and M-ary orthogonal signal sets. The error probability with coding is found and tradeoffs between various coding strategies are determined for the worst case partial-band jammer.","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":"130486896","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/ISSCC.1982.1156288
W. Engeler, R. Baertsch, H. Parks, P. McConnelee, D. Brown
The design and evaluation of a dual 128b binary-analog correlator based on charge transfer technology will be described. Correlator operates from-55° -125°C; dissipates less than 0.5W. Performance is not degraded by charge transfer losses.
{"title":"A Binary-Analog Correlator","authors":"W. Engeler, R. Baertsch, H. Parks, P. McConnelee, D. Brown","doi":"10.1109/ISSCC.1982.1156288","DOIUrl":"https://doi.org/10.1109/ISSCC.1982.1156288","url":null,"abstract":"The design and evaluation of a dual 128b binary-analog correlator based on charge transfer technology will be described. Correlator operates from-55° -125°C; dissipates less than 0.5W. Performance is not degraded by charge transfer losses.","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":"131215943","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.1982.4805946
D. Baker, J. Wieselthier, A. Ephremides, D. McGregor
The use of relays is known to increase the resistance of communication links to interference. In a multi-user network it is necessary to establish robust management techniques that allow the users to take advantage of the relaying power a network inherently possesses. In this paper we consider an Intra Task Force (ITF) Network that operates at HF. We employ a network architecture that provides for the automated selection of relay nodes without the need for a central controller. Under this architecture the network reorganizes itself in response to topology changes such as those that result from jamming. Communication range models suitable for a jammed HF channel are presented. We demonstrate that the combination of spread spectrum signaling, error correcting coding, path redundancy through frequency diversity, and adaptive relaying using automated network restructuring provide this network with a strong defense against jamming.
众所周知，使用中继会增加通信链路对干扰的抵抗力。在多用户网络中，有必要建立健壮的管理技术，使用户能够利用网络固有的中继能力。在本文中，我们考虑了一个在高频下运行的Intra Task Force (ITF)网络。我们采用了一种网络架构，它提供了中继节点的自动选择，而不需要中央控制器。在这种架构下，网络可以根据拓扑结构的变化(如干扰)进行自我重组。提出了适用于被干扰高频信道的通信距离模型。我们证明了扩频信号、纠错编码、通过频率分集实现的路径冗余以及使用自动网络重构的自适应中继的组合为该网络提供了强大的抗干扰能力。
{"title":"Distributed Network Reconfiguration in Response to Jamming at HF","authors":"D. Baker, J. Wieselthier, A. Ephremides, D. McGregor","doi":"10.1109/MILCOM.1982.4805946","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805946","url":null,"abstract":"The use of relays is known to increase the resistance of communication links to interference. In a multi-user network it is necessary to establish robust management techniques that allow the users to take advantage of the relaying power a network inherently possesses. In this paper we consider an Intra Task Force (ITF) Network that operates at HF. We employ a network architecture that provides for the automated selection of relay nodes without the need for a central controller. Under this architecture the network reorganizes itself in response to topology changes such as those that result from jamming. Communication range models suitable for a jammed HF channel are presented. We demonstrate that the combination of spread spectrum signaling, error correcting coding, path redundancy through frequency diversity, and adaptive relaying using automated network restructuring provide this network with a strong defense against jamming.","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":"122877066","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.1982.4805927
Y. Pao, Jai-Dong Kim
An approach to the technical control of the digital transmission facilities of the defense communication system has been described by Jankaukas, Landesberg, Spector and Meyer (ref. 1). The status monitoring and performance assessment functions of that approach are interesting and the fault isolation algorithm is sound in principle. In this paper we report on the results of a study aimed at improving on that fault isolation algorithm with respect to removing certain network partitioning restrictions, decreasing processing time and making it compatible with channel reconfiguration and other resource management options. In our approach, the communications system is described in terms of two linked-list data bases, these being the equipment data base and the communication path data base. For fault isolation, the basic idea is that whenever an exception report is received, pointers from the alarmed piece of equipment point to the paths in which the equipment is located. For each such path, the equipment has an ordinal number stating its position in that path. For an alarmed equipment in a certain path, the equipment ordinal number is compared with the ordinal number of the most up-stream (in the transmission case) faulted equipment. Comparison of the ordinal numbers quickly indicates whether the alarm is real or sympathetic. This approach has been investigated using computer simulation. Channel recogfiguration and management of resources on the basis of needs and priorities have also been shown to be compatible with use of this algorithm.
{"title":"A Linked-List Data Base Approach to the Control of the Digital Transmission Facilities of the Defense Communications System","authors":"Y. Pao, Jai-Dong Kim","doi":"10.1109/MILCOM.1982.4805927","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805927","url":null,"abstract":"An approach to the technical control of the digital transmission facilities of the defense communication system has been described by Jankaukas, Landesberg, Spector and Meyer (ref. 1). The status monitoring and performance assessment functions of that approach are interesting and the fault isolation algorithm is sound in principle. In this paper we report on the results of a study aimed at improving on that fault isolation algorithm with respect to removing certain network partitioning restrictions, decreasing processing time and making it compatible with channel reconfiguration and other resource management options. In our approach, the communications system is described in terms of two linked-list data bases, these being the equipment data base and the communication path data base. For fault isolation, the basic idea is that whenever an exception report is received, pointers from the alarmed piece of equipment point to the paths in which the equipment is located. For each such path, the equipment has an ordinal number stating its position in that path. For an alarmed equipment in a certain path, the equipment ordinal number is compared with the ordinal number of the most up-stream (in the transmission case) faulted equipment. Comparison of the ordinal numbers quickly indicates whether the alarm is real or sympathetic. This approach has been investigated using computer simulation. Channel recogfiguration and management of resources on the basis of needs and priorities have also been shown to be compatible with use of this algorithm.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"25 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":"121086738","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.1982.4805981
Lawrence F. Chesto
Because there is a growing number of spread spectrum systems being developed and these systems do not fit the normal frequency allocation and assignment scheme, there is an urgent requirement to improve the process for radio frequency supportability and assignment of systems employing spread spectrum techniques. Spectrum supportability is required before major telcommunications systems can be developed, however, for spread spectrum operations it is hampered by spectrum allocation and compatibility problems. Current policy on spectrum allocation and use does not address spread spectrum technology as such. Comprehensive electromagnetic compatibility analysis and testing is required to achieve approval for operation. This paper addresses some of the problems and solutions for obtaining spectrum support and frequency assignment for spread spectrum systems. It is hoped the reader will become more aware of the radio frequency support and assignment requirements, and utilize this knowledge to avoid the cost of developing a spread spectrum system in a band where no or minimal spectrum support can be obtained.
{"title":"Spread Spectrum and Frequency Management","authors":"Lawrence F. Chesto","doi":"10.1109/MILCOM.1982.4805981","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805981","url":null,"abstract":"Because there is a growing number of spread spectrum systems being developed and these systems do not fit the normal frequency allocation and assignment scheme, there is an urgent requirement to improve the process for radio frequency supportability and assignment of systems employing spread spectrum techniques. Spectrum supportability is required before major telcommunications systems can be developed, however, for spread spectrum operations it is hampered by spectrum allocation and compatibility problems. Current policy on spectrum allocation and use does not address spread spectrum technology as such. Comprehensive electromagnetic compatibility analysis and testing is required to achieve approval for operation. This paper addresses some of the problems and solutions for obtaining spectrum support and frequency assignment for spread spectrum systems. It is hoped the reader will become more aware of the radio frequency support and assignment requirements, and utilize this knowledge to avoid the cost of developing a spread spectrum system in a band where no or minimal spectrum support can be obtained.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"6 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":"116905995","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.1982.4805983
R. Eschenbach
This paper describes an operating, radio communication system intended for indoor use. The problems of multipath are discussed and the use of spread spectrum to overcome these problems is described. Two receiver implementations were constructed and a surface acoustic wave correlator version is described in detail. The system operates at a data rate of 100 Kbps over a range of 1000 meters with a power of 50 milliwatts.
{"title":"Applications of Spread Spectrum Radio to Indoor Data Communications","authors":"R. Eschenbach","doi":"10.1109/MILCOM.1982.4805983","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805983","url":null,"abstract":"This paper describes an operating, radio communication system intended for indoor use. The problems of multipath are discussed and the use of spread spectrum to overcome these problems is described. Two receiver implementations were constructed and a surface acoustic wave correlator version is described in detail. The system operates at a data rate of 100 Kbps over a range of 1000 meters with a power of 50 milliwatts.","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":"129510583","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.1982.4805913
J. E. Blanchard
A frequency hopping technique capable of defeating the repeat jammer independent of the hop rate is presented. This technique, random frequency shift keying/frequency hopping (FSK/FH), is described and analyzed. Specific results are given for 2-ary, 4-ary and 8-ary random FSK/FH against repeat noise, repeat tone, and combined repeat tone and noise jamming with and without error correction coding. These analyses show that random FSK/FH is an effective countermeasure to the repeat jammer.
{"title":"A Slow Frequency Hopping Technique that is Robust to Repeat Jamming","authors":"J. E. Blanchard","doi":"10.1109/MILCOM.1982.4805913","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805913","url":null,"abstract":"A frequency hopping technique capable of defeating the repeat jammer independent of the hop rate is presented. This technique, random frequency shift keying/frequency hopping (FSK/FH), is described and analyzed. Specific results are given for 2-ary, 4-ary and 8-ary random FSK/FH against repeat noise, repeat tone, and combined repeat tone and noise jamming with and without error correction coding. These analyses show that random FSK/FH is an effective countermeasure to the repeat jammer.","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":"129256613","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.1982.4806026
A. Kelly, E. Newman
A high gain, multi-beam microstrip array, and associated multi-channel low noise front end, has been developed for use in experiments relating to advanced troposcatter communication techniques over the 4.4 to 5.0 GHz band. A 10-foot square antenna provides a cluster of orthogonal beams. Two smaller antennas are included. This array permits angle diversity reception, as well as experiments related to Electronic Counter-Countermeasures (ECCM). The radiating elements are wideband dual polarized slots etched in the common ground plane of a pair of microstrip substrates. Each substrate contains the feed circuitry for one polarization. The multi-channel tunable front end exhibits noise figures less than 3.8 dB. It has been designed for extremely low delay distortion, so as to minimize corruption of the signal. A tunable cavity preselector, GaAs FET LNA and thin-film image-reject mixer-preamplifier comprise each channel. The array has proven to be efficient, and capable of wideband performance. The high end performance was impacted by the choice of element spacing. Future arrays will have tighter spacing, to place the grating lobe further away from real space.
{"title":"Microstrip Array for Troposcatter Communications","authors":"A. Kelly, E. Newman","doi":"10.1109/MILCOM.1982.4806026","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806026","url":null,"abstract":"A high gain, multi-beam microstrip array, and associated multi-channel low noise front end, has been developed for use in experiments relating to advanced troposcatter communication techniques over the 4.4 to 5.0 GHz band. A 10-foot square antenna provides a cluster of orthogonal beams. Two smaller antennas are included. This array permits angle diversity reception, as well as experiments related to Electronic Counter-Countermeasures (ECCM). The radiating elements are wideband dual polarized slots etched in the common ground plane of a pair of microstrip substrates. Each substrate contains the feed circuitry for one polarization. The multi-channel tunable front end exhibits noise figures less than 3.8 dB. It has been designed for extremely low delay distortion, so as to minimize corruption of the signal. A tunable cavity preselector, GaAs FET LNA and thin-film image-reject mixer-preamplifier comprise each channel. The array has proven to be efficient, and capable of wideband performance. The high end performance was impacted by the choice of element spacing. Future arrays will have tighter spacing, to place the grating lobe further away from real space.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"28 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":"130189365","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.1982.4805901
D. Brown, S. Lee, H. Sunkenberg, H. dePedro
Nodes of the MX system can communicate effectively in a trans-or post-attack environment by using a simulcast network that employs groundwave propagation. For a sufficiently dense original network, the simulcast approach is relatively insensitive to degrading channel conditions and loss of nodes and links. Network performance is a complicated function of the radio and antenna designs, terrain in the deployment area, destruction level, network topology and method of control, and channel conditions. In order to systematically evaluate the key parameters affecting performance and, in turn, to optimize their joint selection for various deployment alternatives, the radio network simulator (RNS) was developed. This paper focuses on the application of the RNS to the system design process. After a discussion of the modeling techniques used in the simulation, its utilization for performance assessment and tradeoff evaluation are presented. Specific areas considered include data rate and attack analysis.
{"title":"Computer Modeling of the MX Simulcast Radio Network","authors":"D. Brown, S. Lee, H. Sunkenberg, H. dePedro","doi":"10.1109/MILCOM.1982.4805901","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805901","url":null,"abstract":"Nodes of the MX system can communicate effectively in a trans-or post-attack environment by using a simulcast network that employs groundwave propagation. For a sufficiently dense original network, the simulcast approach is relatively insensitive to degrading channel conditions and loss of nodes and links. Network performance is a complicated function of the radio and antenna designs, terrain in the deployment area, destruction level, network topology and method of control, and channel conditions. In order to systematically evaluate the key parameters affecting performance and, in turn, to optimize their joint selection for various deployment alternatives, the radio network simulator (RNS) was developed. This paper focuses on the application of the RNS to the system design process. After a discussion of the modeling techniques used in the simulation, its utilization for performance assessment and tradeoff evaluation are presented. Specific areas considered include data rate and attack analysis.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"111 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":"124703631","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.1982.4806022
K. Farber, J. Pan, R. Varley
EHF MILSATCOM earth terminals are rapidly becoming a reality. EHF power sources (transmitters) are both a high technology and large production cost element of most terminal implementation approaches. To provide the MILSATCOM community with a current technology status, an industry survey has been conducted among several governmental procurement organizations and potential industry suppliers. The survey, as presented in this paper, addresses specific needs of planned terminals at 45 and 30 GHz. Both devices and high-power amplifiers (HPA's) are investigated in the survey, with particular attention given to near-term requirements. The paper considers both TWT and solid-state devices available now as developmental products. IMPATT diodes provide the most extensive effort to date in solid-state device technology, with power FET's offering a long-term solution with some inherent circuit combining advantages. IMPATT diodes are under development applying silicon (Si), gallium arsenide (GaAs), and indium phosphide (InP), materials to device requirements on a frequency selective basis. Current TWT technology is centered around coupled cavity and wound-helix slow-circuit approaches. A brief review of major EHF MILSATCOM earth terminal requirements is presented as it relates to the transmitter power and platform constraints.
{"title":"EHF Power Generation for Tactical, Mobile and Strategic MILSATCOM Terminals","authors":"K. Farber, J. Pan, R. Varley","doi":"10.1109/MILCOM.1982.4806022","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806022","url":null,"abstract":"EHF MILSATCOM earth terminals are rapidly becoming a reality. EHF power sources (transmitters) are both a high technology and large production cost element of most terminal implementation approaches. To provide the MILSATCOM community with a current technology status, an industry survey has been conducted among several governmental procurement organizations and potential industry suppliers. The survey, as presented in this paper, addresses specific needs of planned terminals at 45 and 30 GHz. Both devices and high-power amplifiers (HPA's) are investigated in the survey, with particular attention given to near-term requirements. The paper considers both TWT and solid-state devices available now as developmental products. IMPATT diodes provide the most extensive effort to date in solid-state device technology, with power FET's offering a long-term solution with some inherent circuit combining advantages. IMPATT diodes are under development applying silicon (Si), gallium arsenide (GaAs), and indium phosphide (InP), materials to device requirements on a frequency selective basis. Current TWT technology is centered around coupled cavity and wound-helix slow-circuit approaches. A brief review of major EHF MILSATCOM earth terminal requirements is presented as it relates to the transmitter power and platform constraints.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"32 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":"128106051","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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