Volume 70, Issue 2

October 2020

Guest Editor-in-Chief:
Cor. member Prof. Petko Petkov, D.Sc.
Preface for Issue 2

DOI: 10.47978/TUS.2020.70.02

 AUTOMATIC SOLUTION OF TRANSPORT PROBLEMS USING A NEW ADD-IN TO EXCEL Simona Filipova-Petrakieva, Ivan Stankov PDF OVERVIEW OF THE METHODS FOR SELF-ORGANIZATION IN SWARM ROBOTICS Aleksandar Marinchev PDF PDF REPETITIVE DRC-SYSTEM OF ROBOT-MANIPULATOR FANUC M-430IA/4FH Emil Nikolov, Nina G. Nikolova PDF PDF

AUTOMATIC SOLUTION OF TRANSPORT PROBLEMS USING A NEW ADD-IN TO EXCEL
Simona Filipova-Petrakieva, Ivan Stankov

Abstract
Transport problem is a basic problem arising in transportation the products from several distributors to several clients. The solution of this problem consists of determining optimal transportation according to needed allocations the products. In fact, this problem describes with linear programming model which in general solves with simplex method. The algorithm of this method is a build-in tool for Excel – SOLVER. Unfortunately when it has a large amount of input data the filling of the Excel’s tables is a very difficult process. Thus, in this paper is suggested an add-in which visualize and make easier inputting the initial data. It is based on the Visual Studio tools for development the add-ins for MS Office. The main advantage of this solution consists of a user-friendly interface of the mathematical model of the problem which significantly makes easily and good visualization the input data and final solution in tables. As an illustrative example, the proposed add-in is applied for solving the real problem connected with transportation the products of pharmacy company.

Keywords
transport problems (closed and open – with insufficiency or overstock); Simplex method; Add-in to Excel for good data visualization, created by Visual Studio Tools for MS Office.

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DOI: 10.47978/TUS.2020.70.02.007

References:

[1] Taha, H. Operations research: an introduction, 10-th edition, Pearson, Print ISBN: 9780134444017, 0134444019, eText ISBN: 9780134480190, 0134480198, 2017.
[2] Transportation Problem. (n.d.) McGraw-Hill Dictionary of Scientific & Technical Terms, 6E. (2003). Retrieved April 6 2020 from https://encyclopedia2.thefreedictionary.com/Transportation+Problem
[3] Transportation Problem. (n.d.) The Great Soviet Encyclopedia, 3rd Edition. (1970-1979). Retrieved April 6 2020 from https://encyclopedia2.thefreedictionary.com/Transportation+Problem
[4] Petrakieva, S., G. Georgieva-Taskova. Automatic solution of transport problems with Excel, 13-th International Conference "Challenges in Higher Education Research in 21-st century", Sozo-pol, Bulgaria, ISBN: 978-954-580-356-7, pp. 91-95, June 2015.
[5] Georgiev I., St. Karakoleva. Solving transport problems with Matlab, Proceeding of Scientific Student Session, Rousse, ISSN: 1311-3321, pp. 30-35, 1999.
[6] Kolman, B., R. Beck. Special Types of Linear Programming Problems, in Elementary Linear Programming with Applications (Second Edition), 1995.
https://doi.org/10.1016/B978-012417910-3/50008-5
https://www.sciencedirect.com/topics/computer-science/transportation-problem
[7] Tavana, M., K. Puranam, Handbook of Research on Organizational Transformations through Big Data Analytics, ISBN-13: 9781466672727, ISBN-10: 1466672722, EISBN-13: 9781466672734, November 2014.
https://doi.org/10.4018/978-1-4666-7272-7
https://www.igi-global.com/dictionary/solving-solid-transportation-problems-with-multi-choice-cost-and-stochastic-supply-and-demand/43346
[8] Petrakieva S. Automatic solution of transport problems with Excel, 14-th International Confer-ence "Challenges in Higher Education Research in 21-st century", Sozopol, Bulgaria, pp. 46-49, 31 May - 3 June 2016.

FOUR-DIMENSIONAL ENCODING OF CHARACTER SEQUENCES AND EVALUATION OF THEIR SIMILARITIES AND DIFFERENCES
Martin Marinov

Abstract
This paper describes a string encoding algorithm, which produces sparse distributed representations (SDR) of text data. In essence, this is a modified version of a prior algorithm and the modifications have the following benefits:

• the ability to decode data, without loss of information;
• greatly increased capacity of the encoding space;
• the possibility of performing more detailed comparisons of encoded strings.

The main disadvantage compared to the prior algorithm is the increased complexity of the procedure for encoded string comparison. This is due to the use of a four-dimensional encoding space, instead of a two-dimensional space.

Keywords
NLP, languages, text mining, unstructured text, data cleaning, data preparation, sparse data representation, SDR.

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DOI: 10.47978/TUS.2020.70.02.008

References:

[1] Годишник на Технически Университет-София, том 68, книга 2, 2018, http://proceedings.tu-sofia.bg/
[2] M. Marinov, A. Efremov, Representing Character Sequences as Sets: A simple and intuitive string encoding algorithm for NLP data cleaning, 2019 IEEE International Conference on Advanced Scientific Computing (ICASC), Romania, 2019, pp. 1-6.
https://doi.org/10.1109/ICASC48083.2019.8946281

OVERVIEW OF THE METHODS FOR SELF-ORGANIZATION IN SWARM ROBOTICS
Aleksandar Marinchev

Abstract
Self-organization is a common phenomenon observed in many natural and artificial systems. The overall coordinated behavior of the system is due to simple rules for interaction between its components. Thanks to these properties, self-organization plays a key role in swarm robotics, as it allows swarm coordination with minimal com-plexity of individual robots.
This paper reviews the methods and tools for self-organization that are used in swarm robotics or are found in natural systems.

Keywords
self-organization, swarm robotics, distributed systems.

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DOI: 10.47978/TUS.2020.70.02.009

References:

[1] Egbert, M., Gruenert, G., Ibrahim, B., Dittrich P., Combining evolution and self-organization to find natural Boolean representations in unconventional computational media, Elsevier B.V. BioSystems, Volume 184, art.104011, 2019.
https://doi.org/10.1016/j.biosystems.2019.104011
[2] Garnier, S., Gautrais, J.,Theraulaz, G., The biological principles of swarm intelligence, Swarm Intelligence. 1. pp. 3-31, 2007.
https://doi.org/10.1007/s11721-007-0004-y
[3] Mondada, Fr., et al., Swarm-Bot: a New Distributed Robotic Concept, Kluwer Academic Pub-lishers, Netherlands., 2004.
[4] Trianni, V., Nolfi, S., Self-Organizing Sync in a Robotic Swarm: A Dynamical System View. Evolutionary Computation, IEEE Transactions on Evolutionary Computation. 13(4). pp. 722 - 741, 2009.
https://doi.org/10.1109/TEVC.2009.2015577
[5] El Zoghby, N., et al., Robot Cooperation and Swarm Intelligence, World Scientific Publishing Company, pp.168-201, 2014.
https://doi.org/10.1142/9789814551342_0008
[6] Gardner, M., Mathematical Games: The fantastic combinations of John Conway's new solitaire game "Life", Scientific American. 223. pp. 120-123. ISBN 0-89454-001-7, 1970.
https://doi.org/10.1038/scientificamerican1070-120
[7] Song, Y., et al., A novel foraging algorithm for swarm robotics based on virtual pheromones and neural network, Elsevier B.V. Applied Soft Computing Journal, Volume 90, art. 106156, 2020.
https://doi.org/10.1016/j.asoc.2020.106156
[8] Bao, D., Zelinka, I., Obstacle Avoidance for Swarm Robot Based on Self-Organizing Migrat-ing Algorithm, Elsevier B.V. Procedia Computer Science, Volume 150, pp. 425-432, 2019.
https://doi.org/10.1016/j.procs.2019.02.073
[9] Osaba, E., et al., Soft Computing for Swarm Robotics: New Trends and Applications, Elsevier B.V. Journal of Computational Science, Volume 39, art. 101049, 2020.
https://doi.org/10.1016/j.jocs.2019.101049
[10] Misir, O., et al., Fuzzy-based self organizing aggregation method for swarm robots, Elsevier B.V. BioSystems, BIO 104187, 2020.
https://doi.org/10.1016/j.biosystems.2020.104187
[11] Garcia-Aunon, P., Cruz, A., Control optimization of an aerial robotic swarm in a search task and its adaptation to different scenarios, Elsevier B.V. Journal of Computational Science, Vol-ume 29, pp. 107-118, 2018.
https://doi.org/10.1016/j.jocs.2018.10.004
[12] Innocente, M., Grasso, P., Self-organising swarms of firefighting drones: Harnessing the powerof collective intelligence in decentralised multi-robot systems, Elsevier B.V. Journal of Computational Science, Volume 34, pp. 80-101, 2019.
https://doi.org/10.1016/j.jocs.2019.04.009
[13] Peng, Y., et al., Swarm robotics platform for intelligent interaction, Virtual Reality & Intelli-gent Hardware, Vol. 1 Issue 3, pp. 316-329, 2019.
https://doi.org/10.3724/SP.J.2096-5796.2019.0019
[14] Nedjah, N., Silva, L., Review of methodologies and tasks in swarm robotics towards standard-ization, Elsevier B.V. Swarm and Evolutionary Computation, Volume 50, art. 100565, 2019.
https://doi.org/10.1016/j.swevo.2019.100565

SURVEY AND ADJUSTMENT OF CONTROLLER OF A GRAPH-ANALYTICAL METHOD TO A SECOND ORDER OBJECT
Boris Grasiani

Abstract
This paper proposes to adjust the controller using a graph-analytical method in the complex plane. The various configurations regarding the location of zeros and poles to those of the object are also considered. Adjusted controllers are surveyed, such as they are integrated into control systems, and some of the quality indicators of an automatic control system are analyzed.

Keywords
complex plane, control systems, quick response.

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DOI: 10.47978/TUS.2020.70.02.010

References:

[1] Николова Н., Николов Е. (2006), Методи и алгоритми за настройка на регулатори в сис-теми за управление справочно пособие по дисциплината "Приложни методи за управле-ние на технологични процеси", София 2006 изд. на Технически Университет София, ISBN 13 : 978-954-438579-8, 72 стр.
[2] Николов Е. (2003), Приложни методи за управление на технологични процеси - първа част (честотни методи и системи с робастни свойства) , Изд. на Технически университет - София, София , 2003 г., ISBN: 954-438-334-4 , 358 стр.
[3] Николова Н., Николов Е. (2009), Приложни методи за управление на технологични про-цеси (ръководство за лабораторни упражнения), Изд. на Технически университет - Со-фия, София, 2009 г. , ISBN: 978-954-438-784-6 , 120 стр.
[4] Houpis C., S. Rasmussen (1999), Quantitative Feedback Theory, Marcel Dekker Inc., 1999.
[5] Vessela Karlova-Sergieva (2011), Quantitative Feedback Theory - Control Systems Design Methodology - part 1, part 1, Journal "Proceedings of Technical University of Sofia" Vol 61, ISSN 1311-0829 Issue 1 (2011).
[6] Vessela Karlova-Sergieva (2012), Modified Techniques in the Complex Plane Journal "Proceedings of Tеchnical University of Sofia" Vol 62, Issue 2, (2012), ISSN 1311-0829, pp110-116.
[7] Vessela Karlova-Sergieva, Modelling of Uncertainty in the Plant Parameters Journal "Proceedings of Technical University of Sofia" , ISSN 1311-0829 ,Vol 62, Issue 4, (2012).
[8] Stanislav Enev, Vessela Karlova-Sergieva (2013), Design of Control Systems for Processes with Significant Time-Delay by Using the Quantitative Feedback Theory Journal "Proceedings of Technical University of Sofia", ISSN 1311-0829 , Vol 63, Issue 4 (2013).
[9] Vessela Karlova-Sergieva Design of Controllers for Unstable Uncertain Plants (part I, part II) Journal "Proceedings of Technical University of Sofia" Vol 65, ISSN 1311-0829, Issue 2 (2015).
[10] Vessela Karlova-Sergieva (2015), Control Systems with Conditional Feedback Journal "Pro-ceedings of Technical University of Sofia" , ISSN 1311-0829 , Vol 66, Issue 2 (2016).
[11] Весела Карлова (2013), Проектиране на системи за управление с гарантирано качество, 2013 Издание на ТУ-София, Радикс ООД, ISBN 978-619-7140-01-9, ISBN 978-619-7140-02-6, 163 стр.
[12] Нина Г. Николова (2019), Робастно репетитивно управление на системи с априорна неопределеност, Изд. Технически Университет София, 2019, ISBN 978-619-167-371-1, 176 стр.
[13] Nikolov E., S. Enev (2009), Asservissement et Régulation Continue, Sofia 2009,2009 Pub-lishing House of Technical University of Sofia; ISBN-978-954-438-814-0, 160 р.
[14] Kostadin Kostov (2007), Asservissement et Régulation - Travaux de laboratoire et exercices assistée par ordinateur, 2007 Université Technique de Sofia, ISBN 978-954-438-604-7, 2007, 116 p.
[15] Nikolov E., D. Jolly, N. Nikolova, B. Benova (2005), Commande Robuste, Sofia 2005, 2005 Publishing House of Technical University of Sofia, ISBN 954-438-500-2, 216 p.

REPETITIVE DRC-SYSTEM OF ROBOT-MANIPULATOR FANUC M-430IA/4FH
Emil Nikolov, Nina G. Nikolova

Abstract
A repetitive ML-DRC-system for an industrial robot manipulator has been proposed and analyzed. The performance and filtering properties of the system to effectively compensate for production mechanical vibrations have been studied. Results of robust analysis in conditions of a priori uncertainty are presented.

Keywords
Repetitive ML-DRC-system, mechanical vibration filtration, robust analysis.

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DOI: 10.47978/TUS.2020.70.02.011

References:

1. Cong Wang, Wenjie Chen, Masayoshi Tomizuka (2012), Robot End-effector Sensing with Position Sensitive Detector and Inertial Sensors, In Proc. of 2012 IEEE International Conference on Robotics and Automation River Centre, Saint Paul, Minnesota, USA, May 14-18, 2012, 978-1-4673-1405-3/12/\$31.00 ©2012 IEEE, 5252-5257
https://doi.org/10.1109/ICRA.2012.6225180
2. Masayoshi Tomizuka (2013), Control Methodologies for Manufacturing Applications, Manufacturing Letters, 2013 Elsevier, 1 (2013), 46-48
https://doi.org/10.1016/j.mfglet.2013.09.010
3. Shouren Huang, Niklas Bergström, Yuji Yamakawa, Taku Senoo, Masatoshi Ishikawa (2016), High-Performance Robotic Contour Tracking Based on the Dynamic Compensation Concept, In Proc. of 2016 IEEE International Conference on Robotics and Automation (ICRA), 2016 IEEE, Electronic ISBN: 978-1-4673-8026-3, DOI: 10.1109/ICRA.2016.7487577, 3886-3893
https://doi.org/10.1109/ICRA.2016.7487577
4. Xu Chen, Atsushi Oshima, Masayoshi Tomizuka (2013), Inverse-Based Local Loop Shaping and IIR-Filter Design for Precision Motion Control, In Proc. of 6th IFAC Symposium on Mechatronic Systems The International Federation of Automatic Control, April 10-12, 2013. Hangzhou, China, 2013 Elsevier, 978-3-902823-31-1/13/\$20.00 © 2013 IFAC, 10.3182/20130410-3-CN-2034.00066, 490-497
5. Xu Chen, Masayoshi Tomizuka (2012), A Minimum Parameter Adaptive Approach for Re-jecting Multiple Narrow-Band Disturbances with Application to Hard Disk Drives, IEEE Transactions on Control System Technology, 2012 IEEE, 20(2), doi:10.1109/TCST.2011.2178025, 408-415
https://doi.org/10.1109/TCST.2011.2178025
6. Youngwoo Lee, Liting Sun, Jun Moon, Chung Choo Chung, Masayoshi Tomizuka (2019), Reference Modulation for Performance Enhancement of Motion Control Systems with Nonlin-ear Parameter Variations, IEEE/ASME Transactions on Mechatronics, July 2019, DOI: 10.1109/TMECH.2019.2930087, pp.1-8
https://doi.org/10.1109/TMECH.2019.2930087
7. E. Nikolov (2019), DRC-Systems - Invers Solutions with Fractional Clegg-Operators - part 1, part 2, Journal Proceedings of Technical University of Sofia, Volume 69, Issue 3, 2019,  2019 Publishing House of Technical University of Sofia, ISSN 1311-0829, pp. 47-66
https://doi.org/10.47978/TUS.2020.70.02.012
8. E. Nikolov, N.G. Nikolova, M. Georgiev (2020), Description and modelling of robot-manipu-lator FANUC M-430iA/4FH, In the 9-th International Scientific Conference "Engineering, Technologies and Systems", Technical University-Sofia Plovdiv Branch, 14-16 May, Plovdiv, Bulgaria
https://doi.org/10.1088/1757-899X/878/1/012006
9. E. Nikolov, V. Karlova-Sergieva, B. Grasiani (2020), Design control system of robot-manipu-lator FANUC M-430iA/4FH, In the 9-th International Scientific Conference "Engineering, Technologies and Systems", Technical University-Sofia Plovdiv Branch, 14-16 May, Plovdiv, Bulgaria
https://doi.org/10.1088/1757-899X/878/1/012007
10. E. Nikolov, N.G. Nikolova (2020), Performance Analysis and Robust Analysis of the DRC-System of Robot-Manipulator FANUC M-430IA/4FH, In Proc. of IEEE International Conference Automatics and Informatics'2020 (ICAI'20), 1-3 October 2020, Varna, Bulgaria
https://doi.org/10.47978/TUS.2020.70.02.011
11. Nikolova N.G., E. Nikolov (2014), Predictive-Repetitive Control (Applied Methods for Pro-cess Control -part III), 2014 Publishing House of Technical University of Sofia, ISBN 978-619-167-136-6, 158 р. 12. Nikolova N.G., E. Nikolov (2013), Absorptive Repetitive Filters with Operators of General-ized Fractional Calculus, Journal Cybernetics and Information Technologies, 2013, Volume 12, No X, ISSN 1311-9702, 2013 Bulgarian Academy of Sciences, pp. 21-32

DRC-SYSTEMS - INVERS SOLUTIONS WITH FRACTIONAL CLEGG-OPERATORS - PART 3
Emil Nikolov

Abstract

In this work, are proposed, researched and analyzed structure, methods and algorithms for designing of fractional DRC-systems with ML-Clegg-differentiators. For their development, inverse solutions of the synthesis problem were used with the help of rational fractional ML-Clegg-operators from the theory of generalized fractional calculus. Their potentials advantages are proven. Results of perturbation and robust analysis for numerical example are presented.

Keywords
fractional DRC-systems, ML-Clegg-differentiation filters, perturbation and robust quality analysis.

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DOI: 10.47978/TUS.2020.70.02.012

References:

[1] A. Baños, A. Barreiro (2012), Reset Control Systems, in: Advances in Industrial Control, 2012 Springer, ISBN-10: 144712216X, ISBN-13: 978-1447122166, 348 p.
[2] A. Baños, J. Carrasco, A. Barreiro (2011), Reset Times-Dependent Stability of Reset Control Systems, IEEE Trans. Autom. Control 56 (1) (2011) pp. 217-223
https://doi.org/10.1109/TAC.2010.2088892
[3] C. V. Hollot (1997), Revisiting Clegg Integrators: Periodicity, Stability and IQCs, System Structure and Control, © 1997 IFAC Bucharest, Romania, 1997, pp. 31-38
https://doi.org/10.1016/S1474-6670(17)41154-2
[4] Cl. Lorena Garzón-Castro, E. Delgado-Aguilera, J. Alexander Cortés-Romero, E. Tello, G. Mazzanti, Performance of an Active Disturbance Rejection Control on a Simulated Continuous Microalgae Photobioreactor, Computers and Chemical Engineering, ©2018 Elsevier, 117 (2018) 129-144
https://doi.org/10.1016/j.compchemeng.2018.06.006
[5] Guo Y., Wang Y., Xie L., Zheng J. (2009), Stability Analysis and Design of Reset Systems: Theory and an Application, Automatica, 2009 Elsevier, Vol 45 (2), pp. 492-497
https://doi.org/10.1016/j.automatica.2008.08.016
[6] J. C. Clegg (1958), A nonlinear Integrator for Servomechanisms, Transactions of the American Institute of Electrical Engineers 11 (1958), Part II: Applications and Industry, 1958 IEEE, Volume: 77, Issue: 1, March 1958, pp. 41-42
https://doi.org/10.1109/TAI.1958.6367399
[7] Hao An, Qianqian Wu, Disturbance rejection dynamic inverse control of air-breathing hypersonic vehicles, Acta Astronautica, © 2018 IAA Published by Elsevier, 151 (2018) 348-356
https://doi.org/10.1016/j.actaastro.2018.06.022
[8] Hebertt Sira-Ramírez, Alberto Luviano-Juárez, Eric William Zurita-Bustamante (2017), Active Disturbance Rejection Control of Dynamic Systems, A Flatness-Based Approach, © 2017 Butterworth-Heinemann, ISBN 978-0-12-849868-2, ISBN: 9780128118955; ISBN: 9780128498682, DOI https://doi.org/10.1016/C2016-0-01983-6, 358 р. https://www.elsevier.com/books/active-disturbance-rejection-control-of-dynamic-systems/9780128498682
[9] Hongyinping Feng, Bao-Zhu Guo, Active disturbance rejection control: Old and New Results, Annual Reviews in Control, © 2017 Elsevier, 44 (2017) 238-248
https://doi.org/10.1016/j.arcontrol.2017.05.003
[10] Kiryakova V. S. (1993), Generalized Fractional Calculus and Applications, CRC Press (December 27, 1993), ISBN: 0582219779, 360 p.
https://doi.org/10.1177/0038038593027002047
[11] Kiryakova V. S., Srivastava H. M. (1993), Generalized (multiple) Riemann-Liouville Fractional Different-Integrals and Their Use in Univalent Function Theory, In: "Analysis, Geometry and Groups: a Riemann Legacy Volume",  Hadronic Press, Inc., (Florida, USA - ISBN 0-911767-59-2), 1993, part. 1, 191 p.
[12] Kiryakova V. S. (1994), Generalized Fractional Calculus and Applications, Pitman Research Notes in Mathematics Series No. 301, Longman Scientific and Technical,  Harlow, Essex, 1994, ISBN: 0-470-20777-9, 260 p.
[13] Kiryakova V. S. (1997), All the Special Functions are Fractional Different-Integrals of Elemen-tary Functions, Journal Physics A: Math. & General, 1997, 30, No 14, Online ISSN: 1361-6447, Print ISSN: 0305-4470, 5085-5103
https://doi.org/10.1088/0305-4470/30/14/019
[14] M. A. Davó, A. Baños (2016), Reset Control of Integrating Plus Dead Time Processes, Journal of Process Control,  2016 Elsevier, ISSN: 0959-1524, Vol. 38 (2016) pp. 22-30
https://doi.org/10.1016/j.jprocont.2015.12.001
[15] Oustaloup A. (1991), La commande CRONE (commande robuste d'ordre non entier), Hermès (Traité des Nouvelles Technologies - Série Automatique), Paris, ISBN 2-86601-289-5, ISBN 0989-3571, 495 p.
[16] Oustaloup A. (1994), La robustesse (analyse et synthèse de commandes robustes), Hermès (Traité des Nouvelles Technologies - Série Automatique), Paris, ISBN-10: 2866014421, ISBN-13: 978-2866014421, 530 p.
[17] Oustaloup A. (1995), La dérivation non entière (théorie, synthèse et applications),  Hermès (Traité des Nouvelles Technologies - Série Automatique), Paris, ISBN 2-86601-456-1, ISBN 0989-3571, 508 p.
[18] Nikolov E. (2004), Fractional Order Control Algorithms and Controllers, Sofia, 2004 Publishing House of Technical University of Sofia, ISBN 954-438-395-6, 2004, 208 p.
[19] Nikolov E. (2016), Application of Generalized Fractional Calculus in Inverse Robust Control - part 1, part 2, Journal Proceedings of Technical University of Sofia, Volume 66, Issue 2, 2016, Publishing House of Technical University of Sofia, ISSN 1311-0829, pp. 15-34
[20] Nikolov E. (2018), Clegg-Operators for Integration and Differentiation. Generalized Reset-Control - part 1, part 2, Journal Proceedings of Technical University of Sofia, Volume 68, Issue 3, 2018, Publishing House of Technical University of Sofia, ISSN 1311-0829, pp. 47-64
[21] Nikolov E. (2019), Fractional Order ML Clegg-Operators, Controllers and ML Reset-Control- part 1, part 2, part 3, Journal Proceedings of Technical University of Sofia, Volume 69, Issue 2, 2019, Publishing House of Technical University of Sofia, ISSN 1311-0829, pp. 183-210
[22] Nikolova N., Nikolov E. (2008), ML-Structures in the Repetitive Robust Control Systems, Journal Cybernetics and Information Technologies Journal, 2008 Bulgarian Academy of Science, ISSN 1311-9702, Vol. 8 (2008), No 1, pp. 44-64
[23] Nikolov E. (2019), DRC-Systems - Invers Solutions with Fractional Clegg-Operators - part 1, Journal Proceedings of Technical University of Sofia, Volume 69, Issue 3, 2019,  2019 Pub-lishing House of Technical University of Sofia, ISSN 1311-0829, pp. 47-56
[24] Nikolov E. (2019), DRC-Systems - Invers Solutions with Fractional Clegg-Operators - part 1, Journal Proceedings of Technical University of Sofia, Volume 69, Issue 3, 2019,  2019 Pub-lishing House of Technical University of Sofia, ISSN 1311-0829, pp. 57-66