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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">mireabulletin</journal-id><journal-title-group><journal-title xml:lang="ru">Russian Technological Journal</journal-title><trans-title-group xml:lang="en"><trans-title>Russian Technological Journal</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2782-3210</issn><issn pub-type="epub">2500-316X</issn><publisher><publisher-name>RTU MIREA</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.32362/2500-316X-2023-11-3-7-16</article-id><article-id custom-type="elpub" pub-id-type="custom">mireabulletin-693</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ИНФОРМАЦИОННЫЕ СИСТЕМЫ. ИНФОРМАТИКА. ПРОБЛЕМЫ ИНФОРМАЦИОННОЙ БЕЗОПАСНОСТИ</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>INFORMATION SYSTEMS. COMPUTER SCIENCES. ISSUES OF INFORMATION SECURITY</subject></subj-group></article-categories><title-group><article-title>Среда исследований операционно-вычислительной архитектуры информационного обеспечения цифровой валюты центрального банка</article-title><trans-title-group xml:lang="en"><trans-title>Development of a research environment for the operational and computational architecture of central bank digital currency software</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-9632-7806</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Албычев</surname><given-names>А. С.</given-names></name><name name-style="western" xml:lang="en"><surname>Albychev</surname><given-names>A. S.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Албычев Александр Сергеевич - заместитель руководителя, Федеральное казначейство МФ РФ; заведующий кафедрой «Государственные финансовые технологии» Института кибербезопасности и цифровых технологий ФГБОУ ВО «МИРЭА - РТУ».</p><p>101000, Москва, Большой Златоустинский пер., д. 6, стр. 1; 119454, Москва, пр-т Вернадского, д. 78</p></bio><bio xml:lang="en"><p>Alexander S. Albychev - Deputy Head of the Federal Treasury, The Ministry of Finance of the Russian Federation; Head of the State Financial Technologies Department, Institute for Cybersecurity and Digital Technologies, MIREA - Russian Technological University.</p><p>6/1, Bol'shoi Zlatoustinskii per., Moscow, 101000; 78, Vernadskogo pr., Moscow, 119454</p></bio><email xlink:type="simple">albychev@mirea.ru</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-1407-2788</contrib-id><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Кудж</surname><given-names>С. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Kudzh</surname><given-names>S. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Кудж Станислав Алексеевич – доктор технических наук, профессор, ректор ФГБОУ ВО «МИРЭА - РТУ».</p><p>119454, Москва, пр-т Вернадского, д. 78</p><p>Scopus Author ID 56521711400</p></bio><bio xml:lang="en"><p>Stanislav A. Kudzh - Dr. Sci. (Eng.), Professor, Rector, MIREA - Russian Technological University.</p><p>78, Vernadskogo pr., Moscow, 119454</p><p>Scopus Author ID 56521711400</p></bio><email xlink:type="simple">rector@mirea.ru</email><xref ref-type="aff" rid="aff-2"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Федеральное казначейство Министерства финансов Российской Федерации; ФГБОУ ВО «МИРЭА - Российский технологический университет»</institution><country>Россия</country></aff><aff xml:lang="en"><institution>The Federal Treasury of the Ministry of Finance of the Russian Federation; MIREA - Russian Technological University</institution><country>Russian Federation</country></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>ФГБОУ ВО «МИРЭА - Российский технологический университет»</institution><country>Россия</country></aff><aff xml:lang="en"><institution>MIREA - Russian Technological University</institution><country>Russian Federation</country></aff></aff-alternatives><pub-date pub-type="collection"><year>2023</year></pub-date><pub-date pub-type="epub"><day>02</day><month>06</month><year>2023</year></pub-date><volume>11</volume><issue>3</issue><fpage>7</fpage><lpage>16</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Албычев А.С., Кудж С.А., 2023</copyright-statement><copyright-year>2023</copyright-year><copyright-holder xml:lang="ru">Албычев А.С., Кудж С.А.</copyright-holder><copyright-holder xml:lang="en">Albychev A.S., Kudzh S.A.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://www.rtj-mirea.ru/jour/article/view/693">https://www.rtj-mirea.ru/jour/article/view/693</self-uri><abstract><sec><title>Цели</title><p>Цели. Внедрение и разработка информационно-вычислительной архитектуры и информационного обеспечения цифровой валюты центрального банка (ЦВЦБ) страны основываются на выборе программно-аппаратной платформы, включая технологии и способы взаимодействия элементов вычислительного комплекса. Внедрение технологий ЦВЦБ существенно зависит как от операционно-вычислительной архитектуры, так и от технологических характеристик конкретной реализации информационного обеспечения цифровой валюты, что определяет необходимость разработки соответствующей среды исследований. Цель статьи - разработка инфраструктуры среды экспериментальных исследований операционно-вычислительной архитектуры информационного обеспечения ЦВЦБ.</p></sec><sec><title>Методы</title><p>Методы. Развитие цифровых технологий не сформировало стек реализации ЦВЦБ, а комплекс технологических реализаций находится в разработке во многих странах мира. Основой для формирования программно-аппаратного комплекса информационного обеспечения являются теоретические и экспериментальные исследования современных инструментов цифрового управления транзакциями.</p></sec><sec><title>Результаты</title><p>Результаты. Рассмотрены архитектурные и технологические компоненты, составляющие операционно-вычислительную среду цифровой валюты центрального банка: операционно-вычислительные архитектуры, блокчейн-технологии, алгоритмы консенсуса, формы представления цифровых валют. Представлено 5 вариантов операционно-вычислительных архитектур ЦВЦБ. Проведено исследование информационных моделей взаимодействия участников транзакций ЦВЦБ, направленных на установление степени влияния архитектурного решения на характеристики вычислительного комплекса информационного обеспечения. Проанализированы особенности цифровых валют в форме аккаунтов и токенов.</p></sec><sec><title>Выводы</title><p>Выводы. Разработана инфраструктура среды исследований операционно-вычислительной архитектуры информационного обеспечения ЦВЦБ. Созданы предпосылки для комплексного анализа технологических характеристик операционно-вычислительной среды ЦВЦБ. Проведен анализ вариантов операционно-вычислительных архитектур. В результате анализа сформирован сводный перечень характеристик приведенных архитектур. В зависимости от требований, предъявляемых к ЦВЦБ, на основе этого перечня может быть выбрана наиболее адекватная операционно-вычислительная архитектура.</p></sec></abstract><trans-abstract xml:lang="en"><sec><title>Objectives</title><p>Objectives. The development and implementation of information and computing architecture and information support for a state central bank digital currency (CBDC) is based on the selection of a software and hardware platform, including technologies and methods for supporting interaction between the elements of the computing complex. The implementation of CBDC technologies significantly depends both on the operational and computing architecture, as well as on the technological characteristics of the means for implementing digital currency information support, which determines the need to develop an appropriate research environment. Thus, the present study sets out to develop an infrastructure for the experimental research environment of the operational and computing architecture used to provide information support for the CBDC.</p></sec><sec><title>Methods</title><p>Methods. Digital technologies required for forming an CBDC implementation stack are under development in many countries of the world. The basis for the formation of a software and hardware complex for providing CBDC information support is comprised of theoretical and experimental studies into contemporary digital transaction management tools.</p></sec><sec><title>Results</title><p>Results. The main architectural and technological components that make up the CBDC operational and computing environment comprise operational and computing architectures, blockchain technologies, consensus algorithms, and various forms of digital currencies. Five CBDC operational and computing architecture options are presented. Information models of interaction between the participants in transactions of the central bank digital currency were studied with the aim of establishing the effects of an architectural solution to the characteristics of the computing complex used to provide information support. Features of various digital currencies in the form of accounts and tokens were analyzed.</p></sec><sec><title>Conclusions</title><p>Conclusions. A research environment infrastructure for the CBDC operational and computing information support architecture has been developed. The prerequisites for a comprehensive analysis of the technological characteristics of the CBDC operational and computing environment are set out along with a comparison of operational and computing architecture variants. As a result of the analysis, a summary list of the characteristics of the studied architectures is drawn up. This provides for selecting the optimal operational and computing architecture depending on the requirements imposed on the CBDC.</p></sec></trans-abstract><kwd-group xml:lang="ru"><kwd>цифровая валюта</kwd><kwd>цифровая валюта центрального банка</kwd><kwd>блокчейн</kwd><kwd>алгоритм консенсуса</kwd><kwd>архитектура цифровой валюты</kwd></kwd-group><kwd-group xml:lang="en"><kwd>digital currency</kwd><kwd>central bank digital currency</kwd><kwd>blockchain</kwd><kwd>consensus algorithm</kwd><kwd>digital currency architecture</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Allen F., Gu X., Jagtiani J. Fintech, cryptocurrencies, and CBDC: Financial structural transformation in China. J. Int. Money Finance. 2022;124(3-4):102625. https://doi.org/10.1016/j.jimonfin.2022.102625</mixed-citation><mixed-citation xml:lang="en">Allen F., Gu X., Jagtiani J. Fintech, cryptocurrencies, and CBDC: Financial structural transformation in China. J. Int. Money Finance. 2022;124(3-4):102625. https://doi.org/10.1016/j.jimonfin.2022.102625</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Wang Y.-R., Ma C.-Q., Ren Y.-S. A model for CBDC audits based on blockchain technology: Learning from the DCEP. Res. Int. Bus. Financ. 2022;63(3):101781. https://doi.org/10.1016/j.ribaf.2022.101781</mixed-citation><mixed-citation xml:lang="en">Wang Y.-R., Ma C.-Q., Ren Y.-S. A model for CBDC audits based on blockchain technology: Learning from the DCEP. Res. Int. Bus. Financ. 2022;63(3):101781. https://doi.org/10.1016/j.ribaf.2022.101781</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">Choi K.J., Henry R., Lehar A., Reardon J., Safavi-Naini R. A proposal for a Canadian CBDC. SSRN Electron. J. 2021. https://doi.org/10.2139/ssrn.3786426</mixed-citation><mixed-citation xml:lang="en">Choi K.J., Henry R., Lehar A., Reardon J., Safavi-Naini R. A proposal for a Canadian CBDC. SSRN Electron. J. 2021. https://doi.org/10.2139/ssrn.3786426</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Chu Y., Lee J., Kim S., Kim H., Yoon Y., Chung H. Review of offline payment function of CBDC considering security requirements. Appl. Sci. 2022;12(9):4488. https://doi.org/10.3390/app12094488</mixed-citation><mixed-citation xml:lang="en">Chu Y., Lee J., Kim S., Kim H., Yoon Y., Chung H. Review of offline payment function of CBDC considering security requirements. Appl. Sci. 2022;12(9):4488. https://doi.org/10.3390/app12094488</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Zhang T., Huang Z. Blockchain and central bank digital currency. ICT Express. 2022;8(2):264-270. https://doi.org/10.1016/j.icte.2021.09.014</mixed-citation><mixed-citation xml:lang="en">Zhang T., Huang Z. Blockchain and central bank digital currency. ICT Express. 2022;8(2):264-270. https://doi.org/10.1016/j.icte.2021.09.014</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Tsai W.-T., Zhao Z., Zhang C., Yu L., Deng E. A multi-chain model for CBDC. In: 2018 5th International Conference on Dependable Systems and Their Applications (DSA). Dalian, China: IEEE; 2018. P. 25-34. https://doi.org/10.1109/DSA.2018.00016</mixed-citation><mixed-citation xml:lang="en">Tsai W.-T., Zhao Z., Zhang C., Yu L., Deng E. A multi-chain model for CBDC. In: 2018 5th International Conference on Dependable Systems and Their Applications (DSA). Dalian, China: IEEE; 2018. P. 25-34. https://doi.org/10.1109/DSA.2018.00016</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Jin S.Y., Xia Y. CEV Framework: A central bank digital currency evaluation and verification framework with a focus on consensus algorithms and operating architectures. IEEE Access. 2022;10:63698-63714. https://doi.org/10.1109/ACCESS.2022.3183092</mixed-citation><mixed-citation xml:lang="en">Jin S.Y., Xia Y. CEV Framework: A central bank digital currency evaluation and verification framework with a focus on consensus algorithms and operating architectures. IEEE Access. 2022;10:63698-63714. https://doi.org/10.1109/ACCESS.2022.3183092</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Opare E.A., Kim K. A compendium of practices for central bank digital currencies for multinational financial infrastructures. IEEE Access. 2020;8:110810-110847. https://doi.org/10.1109/ACCESS.2020.3001970</mixed-citation><mixed-citation xml:lang="en">Opare E.A., Kim K. A compendium of practices for central bank digital currencies for multinational financial infrastructures. IEEE Access. 2020;8:110810-110847. https://doi.org/10.1109/ACCESS.2020.3001970</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Lee Y., Son B., Park S., Lee J., Jang H. A survey on security and privacy in blockchain-based central bank digital currencies. J. Internet Serv. Inform. Secur. 2021;11(3): 16-29. https://doi.org/10.22667/JISIS.2021.08.31.016</mixed-citation><mixed-citation xml:lang="en">Lee Y., Son B., Park S., Lee J., Jang H. A survey on security and privacy in blockchain-based central bank digital currencies. J. Internet Serv. Inform. Secur. 2021;11(3): 16-29. https://doi.org/10.22667/JISIS.2021.08.31.016</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Ballaschk D., Paulick J. The public, the private and the secret: Thoughts on privacy in central bank digital currencies. Journal of Payments Strategy &amp; Systems. 2021;15(3):277-286. Available from URL: https://www.bundesbank.de/resource/blob/880792/7f4b5efd53026f51a9f53b176859e715/mL/digital-currencies-ballaschk-paulick-data.pdf</mixed-citation><mixed-citation xml:lang="en">Ballaschk D., Paulick J. The public, the private and the secret: Thoughts on privacy in central bank digital currencies. Journal of Payments Strategy &amp; Systems. 2021;15(3):277-286. Available from URL: https://www.bundesbank.de/resource/blob/880792/7f4b5efd53026f51a9f53b176859e715/mL/digital-currencies-ballaschk-paulick-data.pdf</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Monrat A.A., Schelen O., Andersson K. A survey of blockchain from the perspectives of applications, challenges, and opportunities. IEEE Access. 2019;7: 117134-117151. https://doi.org/10.1109/ACCESS.2019.2936094</mixed-citation><mixed-citation xml:lang="en">Monrat A.A., Schelen O., Andersson K. A survey of blockchain from the perspectives of applications, challenges, and opportunities. IEEE Access. 2019;7: 117134-117151. https://doi.org/10.1109/ACCESS.2019.2936094</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Hang L., Kim D.-H. Optimal blockchain network construction methodology based on analysis of configurable components for enhancing Hyperledger Fabric performance. Blockchain: Res. Appl. 2021;2(1):100009. https://doi.org/10.1016/j.bcra.2021.100009</mixed-citation><mixed-citation xml:lang="en">Hang L., Kim D.-H. Optimal blockchain network constructionmethodologybasedonanalysisofconfigurable components for enhancing Hyperledger Fabric performance. Blockchain: Res. Appl. 2021;2(1):100009. https://doi.org/10.1016/j.bcra.2021.100009</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Lashkari B., Musilek P. A comprehensive review of blockchain consensus mechanisms. IEEE Access. 2021;9:43620-43652. https://doi.org/10.1109/ACCESS.2021.3065880</mixed-citation><mixed-citation xml:lang="en">Lashkari B., Musilek P. A comprehensive review of blockchain consensus mechanisms. IEEE Access. 2021;9:43620-43652. https://doi.org/10.1109/ACCESS.2021.3065880</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Auer R., Bohme R. The technology of retail central bank digital currency. BIS Quarterly Review. 2020. Available from URL: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3561198</mixed-citation><mixed-citation xml:lang="en">Auer R., Bohme R. The technology of retail central bank digital currency. BIS Quarterly Review. 2020. Available from URL: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3561198</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Ozili P.K. Central bank digital currency research around the world: a review of literature. J. Money Launder. Control. 2022;26(2):215-226. https://doi.org/10.1108/JMLC-11-2021-0126</mixed-citation><mixed-citation xml:lang="en">Ozili P.K. Central bank digital currency research around the world: a review of literature. J. Money Launder. Control. 2022;26(2):215-226. https://doi.org/10.1108/JMLC-11-2021-0126</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Bordo M.D., Levin A.T. Central bank digital currency and the future of monetary policy. NBER Working Paper Series. 2017;Working Paper 23711. https://doi.org/10.3386/w23711</mixed-citation><mixed-citation xml:lang="en">Bordo M.D., Levin A.T. Central bank digital currency and the future of monetary policy. NBER Working Paper Series. 2017;Working Paper 23711. https://doi.org/10.3386/w23711</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Zhang J., Tian R., Cao Y., Yuan X., Yu Z., Yan X., et al. A hybrid model for central bank digital currency based on blockchain. IEEE Access. 2021;9:53589-53601. https://doi.org/10.1109/ACCESS.2021.3071033</mixed-citation><mixed-citation xml:lang="en">Zhang J., Tian R., Cao Y., Yuan X., Yu Z., Yan X., et al. A hybrid model for central bank digital currency based on blockchain. IEEE Access. 2021;9:53589-53601. https://doi.org/10.1109/ACCESS.2021.3071033</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Allen S., Capkun S., Eyal I., Fanti G., Ford B.A., Grimmelmann J., et al. Design choices for central bank digital currency: Policy and technical considerations. NBER Working Paper Series. 2020;Working Paper 27634. https://doi.org/10.3386/w27634</mixed-citation><mixed-citation xml:lang="en">Allen S., Capkun S., Eyal I., Fanti G., Ford B.A., Grimmelmann J., et al. Design choices for central bank digital currency: Policy and technical considerations. NBER Working Paper Series. 2020;Working Paper 27634. https://doi.org/10.3386/w27634</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Chaum D., Grothoff C., Moser T. How to issue a central bank digital currency. SNB Working Papers. 2021;3. 38 p. https://doi.org/10.2139/ssrn.3965032</mixed-citation><mixed-citation xml:lang="en">Chaum D., Grothoff C., Moser T. How to issue a central bank digital currency. SNB Working Papers. 2021;3. 38 p. https://doi.org/10.2139/ssrn.3965032</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Netto M.A.S., Menon S., Vieira H.V., Costa L.T., de Oliveira F.M., Saad R., et al. Evaluating load generation in virtualized environments for software performance testing. In: 2011 IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum. 2011. P. 993-1000. https://doi.org/10.1109/IPDPS.2011.244</mixed-citation><mixed-citation xml:lang="en">Netto M.A.S., Menon S., Vieira H.V., Costa L.T., de Oliveira F.M., Saad R., et al. Evaluating load generation in virtualized environments for software performance testing. In: 2011 IEEE International Symposium on Parallel and Distributed Processing Workshops and Phd Forum. 2011. P. 993-1000. https://doi.org/10.1109/IPDPS.2011.244</mixed-citation></citation-alternatives></ref><ref id="cit21"><label>21</label><citation-alternatives><mixed-citation xml:lang="ru">Албычев А.С., Ильин Д.Ю., Никульчев Е.В., Магомедов Ш.Г. Разработка методики экспериментального исследования технологического обеспечения цифровой валюты центрального банка. Вестник РГРТУ. 2022;82:136-146. https://doi.org/10.21667/1995-4565-2022-82-136-146</mixed-citation><mixed-citation xml:lang="en">Albychev A.S., Ilin D.Y., Nikulchev E.V., Magomedov S.G. Development of a methodology for experimental studies of technologies for central bank digital currencies. Vestnik of RSREU. 2022;82:136-146 (in Russ.). https://doi.org/10.21667/1995-4565-2022-82-136-146</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
