Coordination of autonomic functionalities in communications networks

International audienceFuture communication networks are expected to feature autonomic (or self-organizing) mechanisms to ease de- ployment, tune parameters automatically and repair the network. Self-organizing mechanisms are designed as stand-alone entities, even though multiple mechanisms run in parallel in operational networks. An efficient coordination mechanism will be the major enabler for large scale deployment of self-organizing networks. We model self-organizing mechanisms as control loops, and study the conditions for stability when running control loops in parallel. Based on control theory, we propose a distributed coordination mechanism to stabilize the system. In certain cases, coordination can be achieved without any exchange of information between control loops. The mechanism remains valid in the presence of noise via stochastic approximation. Instability and coordination in the context of wireless networks are illustrated with two examples. We are essentially concerned with linear systems, and the applicability of our results for non-linear systems is discusse

ENERGY-AWARE OPTIMIZATION FOR EMBEDDED SYSTEMS WITH CHIP MULTIPROCESSOR AND PHASE-CHANGE MEMORY

Over the last two decades, functions of the embedded systems have evolved from simple real-time control and monitoring to more complicated services. Embedded systems equipped with powerful chips can provide the performance that computationally demanding information processing applications need. However, due to the power issue, the easy way to gain increasing performance by scaling up chip frequencies is no longer feasible. Recently, low-power architecture designs have been the main trend in embedded system designs. In this dissertation, we present our approaches to attack the energy-related issues in embedded system designs, such as thermal issues in the 3D chip multiprocessor (CMP), the endurance issue in the phase-change memory(PCM), the battery issue in the embedded system designs, the impact of inaccurate information in embedded system, and the cloud computing to move the workload to remote cloud computing facilities. We propose a real-time constrained task scheduling method to reduce peak temperature on a 3D CMP, including an online 3D CMP temperature prediction model and a set of algorithm for scheduling tasks to different cores in order to minimize the peak temperature on chip. To address the challenging issues in applying PCM in embedded systems, we propose a PCM main memory optimization mechanism through the utilization of the scratch pad memory (SPM). Furthermore, we propose an MLC/SLC configuration optimization algorithm to enhance the efficiency of the hybrid DRAM + PCM memory. We also propose an energy-aware task scheduling algorithm for parallel computing in mobile systems powered by batteries. When scheduling tasks in embedded systems, we make the scheduling decisions based on information, such as estimated execution time of tasks. Therefore, we design an evaluation method for impacts of inaccurate information on the resource allocation in embedded systems. Finally, in order to move workload from embedded systems to remote cloud computing facility, we present a resource optimization mechanism in heterogeneous federated multi-cloud systems. And we also propose two online dynamic algorithms for resource allocation and task scheduling. We consider the resource contention in the task scheduling

Electrically controlled long-distance spin transport through an antiferromagnetic insulator

Spintronics uses spins, the intrinsic angular momentum of electrons, as an alternative for the electron charge. Its long-term goal is in the development of beyond-Moore low dissipation technology devices. Recent progress demonstrated the long-distance transport of spin signals across ferromagnetic insulators. Antiferromagnetically ordered materials are however the most common class of magnetic materials with several crucial advantages over ferromagnetic systems. In contrast to the latter, antiferromagnets exhibit no net magnetic moment, which renders them stable and impervious to external fields. In addition, they can be operated at THz frequencies. While fundamentally their properties bode well for spin transport, previous indirect observations indicate that spin transmission through antiferromagnets is limited to short distances of a few nanometers. Here we demonstrate the long-distance, over tens of micrometers, propagation of spin currents through hematite (\alpha-Fe2O3), the most common antiferromagnetic iron oxide, exploiting the spin Hall effect for spin injection. We control the spin current flow by the interfacial spin-bias and by tuning the antiferromagnetic resonance frequency with an external magnetic field. This simple antiferromagnetic insulator is shown to convey spin information parallel to the compensated moment (N\'eel order) over distances exceeding tens of micrometers. This newly-discovered mechanism transports spin as efficiently as the net magnetic moments in the best-suited complex ferromagnets. Our results pave the way to ultra-fast, low-power antiferromagnet-insulator-based spin-logic devices that operate at room temperature and in the absence of magnetic fields

Mechatronic design, experimental setup, and control architecture design of a novel 4 DoF parallel manipulator

"This is an Author's Accepted Manuscript of an article published in [include the complete citation information for the final versíon of the article as published in the Mechanics Based Design of Structures and Machines 2018 [copyright Taylor & Francis], available online at: https://www.tandfonline.com/doi/10.1080/15397734.2017.1355249."[EN] Although parallel manipulators started with the introduction of architectures with six degrees of freedom, a vast number of applications require less than six degrees of freedom. Consequently, scholars have proposed architectures with three and four degrees of freedom, but relatively few four degrees of freedom parallel manipulators have become prototypes, especially of the two rotation and two translation motion types. In this article, we explain the mechatronics design, prototype, and control architecture design of a four degrees of freedom parallel manipulators with two rotation and two translation motions. We chose to design a four degrees of freedom manipulator based on the motion needed to complete the tasks of lower limb rehabilitation. To the author's best knowledge, parallel manipulators between three and six degrees of freedom for rehabilitation of lower limb have not been proposed to date. The developed architecture enhances the three minimum degrees of freedom required by adding a four degrees of freedom, which allows combinations of normal or tangential efforts in the joints, or torque acting on the knee. We put forward the inverse and forward displacement equations, describe the prototype, perform the experimental setup, and develop the hardware and control architecture. The tracking accuracy experiments from the proposed controller show that the manipulator can accomplish the required application.The authors wish to thank the Plan Nacional de I + D, Comision Interministerial de Ciencia y Tecnologia (FEDER-CICYT) for the partial funding of this study under project DPI2013-44227-R. We also want to thank the Fondo Nacional de Ciencia, Tecnologia e Innovacion (FONACIT-Venezuela) for its financial support under the project No. 2013002165.Vallés Miquel, M.; Araujo-Gómez, P.; Mata Amela, V.; Valera Fernández, Á.; Díaz-Rodríguez, M.; Page Del Pozo, AF.; Farhat, N. (2018). Mechatronic design, experimental setup, and control architecture design of a novel 4 DoF parallel manipulator. Mechanics Based Design of Structures and Machines. 46(4):425-439. https://doi.org/10.1080/15397734.2017.1355249S425439464Araujo-Gómez, P., Díaz-Rodriguez, M., Mata, V., Valera, A., & Page, A. (2016). Design of a 3-UPS-RPU Parallel Robot for Knee Diagnosis and Rehabilitation. 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(2003). Architecture optimization of a 3-DOF translational parallel mechanism for machining applications, the orthoglide. IEEE Transactions on Robotics and Automation, 19(3), 403-410. doi:10.1109/tra.2003.810242Clavel, R. (1988). A Fast Robot with Parallel Geometry. Proc. Int. Symposium on Industrial Robots, Lausanne, Switzerland, 91–100.Díaz, I., Gil, J. J., & Sánchez, E. (2011). Lower-Limb Robotic Rehabilitation: Literature Review and Challenges. Journal of Robotics, 2011, 1-11. doi:10.1155/2011/759764Díaz-Rodríguez, M., Mata, V., Valera, Á., & Page, Á. (2010). A methodology for dynamic parameters identification of 3-DOF parallel robots in terms of relevant parameters. Mechanism and Machine Theory, 45(9), 1337-1356. doi:10.1016/j.mechmachtheory.2010.04.007Escamilla, R. F., MacLeod, T. D., Wilk, K. E., Paulos, L., & Andrews, J. R. (2012). Cruciate ligament loading during common knee rehabilitation exercises. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 226(9), 670-680. doi:10.1177/0954411912451839Gan, D., Dai, J. S., Dias, J., Umer, R., & Seneviratne, L. (2015). Singularity-Free Workspace Aimed Optimal Design of a 2T2R Parallel Mechanism for Automated Fiber Placement. Journal of Mechanisms and Robotics, 7(4). doi:10.1115/1.4029957Garage, W. (2009). Robot Operating System. www.ros.org. Accessed date: August 2nd, 2017.Girone, M., Burdea, G., Bouzit, M., Popescu, V., & Deutsch, J. E. (2001). Autonomous Robots, 10(2), 203-212. doi:10.1023/a:1008938121020Gough, V., Whitehall, S. (1962). Universal Tyre Test Machine. Proceedings 9th Int. Technical Congress FISITA, London, vol. 117, 117–135.Jamwal, P. K., Hussain, S., & Xie, S. Q. (2013). Review on design and control aspects of ankle rehabilitation robots. Disability and Rehabilitation: Assistive Technology, 10(2), 93-101. doi:10.3109/17483107.2013.866986Lee, K.-M., & Arjunan, S. (1992). A Three Degrees of Freedom Micro-Motion In-Parallel Actuated Manipulator. Precision Sensors, Actuators and Systems, 345-374. doi:10.1007/978-94-011-1818-7_9Li, Y., & Xu, Q. (2007). Design and Development of a Medical Parallel Robot for Cardiopulmonary Resuscitation. IEEE/ASME Transactions on Mechatronics, 12(3), 265-273. doi:10.1109/tmech.2007.897257Mohan, S., Mohanta, J. K., Kurtenbach, S., Paris, J., Corves, B., & Huesing, M. (2017). Design, development and control of a 2PRP-2PPR planar parallel manipulator for lower limb rehabilitation therapies. Mechanism and Machine Theory, 112, 272-294. doi:10.1016/j.mechmachtheory.2017.03.001Ortega, R., & Spong, M. W. (1989). Adaptive motion control of rigid robots: A tutorial. Automatica, 25(6), 877-888. doi:10.1016/0005-1098(89)90054-xPierrot, F., Company, O. (1999). H4: A New Family of 4 DoF Parallel Robots. Proceedings of 1999 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Georgia, USA, 508–513.Ramsay, J. O., & Silverman, B. W. (1997). Functional Data Analysis. Springer Series in Statistics. doi:10.1007/978-1-4757-7107-7Rastegarpanah, A., Saadat, M., & Borboni, A. (2016). Parallel Robot for Lower Limb Rehabilitation Exercises. Applied Bionics and Biomechanics, 2016, 1-10. doi:10.1155/2016/8584735Stewart, D. (1965). A Platform with Six Degrees of Freedom. Proceedings of the Institution of Mechanical Engineers, 180(1), 371-386. doi:10.1243/pime_proc_1965_180_029_02Vallés, M., Cazalilla, J., Valera, Á., Mata, V., Page, Á., & Díaz-Rodríguez, M. (2015). A 3-PRS parallel manipulator for ankle rehabilitation: towards a low-cost robotic rehabilitation. Robotica, 35(10), 1939-1957. doi:10.1017/s0263574715000120Vallés, M., Díaz-Rodríguez, M., Valera, Á., Mata, V., & Page, Á. (2012). Mechatronic Development and Dynamic Control of a 3-DOF Parallel Manipulator. Mechanics Based Design of Structures and Machines, 40(4), 434-452. doi:10.1080/15397734.2012.687292Xu, W. L., Pap, J.-S., & Bronlund, J. (2008). Design of a Biologically Inspired Parallel Robot for Foods Chewing. IEEE Transactions on Industrial Electronics, 55(2), 832-841. doi:10.1109/tie.2007.909067Yoon, J., Ryu, J., & Lim, K.-B. (2006). Reconfigurable ankle rehabilitation robot for various exercises. Journal of Robotic Systems, 22(S1), S15-S33. doi:10.1002/rob.20150Zarkandi, S. (2011). Kinematics and Singularity Analysis of a Parallel Manipulator with Three Rotational and One Translational DOFs. Mechanics Based Design of Structures and Machines, 39(3), 392-407. doi:10.1080/15397734.2011.55914

Confidentiality of XML documents by pool encryption

The eXtensible Markup Language (XML) is a widely adopted format for documents containing structured information. Structured information contains both the content (words, images etc.) and the ‘markup’ which indicates the role of the content, e.g. ‘section’ or ‘price’. XML is the foundation for a huge variety of existing and emerging applications, including user applications like vector imaging formats, web pages, enterprise application integration, database interfaces or network protocols. Parallel to the increasing use of XML, the level of security provisions for these XML based systems rises. The World Wide Web Consortium (W3C) addressed these issues by creating the “XML Signature Syntax and Processing” and “XML Encryption Syntax and Processing” recommendations. These standards define authentication, integrity and confidentiality mechanisms for XML documents. The XML Signature recommendation defines a method for digitally signing arbitrary portions (nodes) of an XML document. XML Signature can sign both tree structures and arbitrary sets of nodes of an XML document. The XML Encryption recommendation specifies a method for encrypting tree structures in an XML document. The XML Encryption recommendation is constrained to protect full tree structures, i.e. there is no mechanism to protect the confidentiality of a single node in a document without affecting the descendants of that node. The access control community transformed access control models originating in database systems to be available for XML based databases. These access control systems offer fine-grained access control enforcement on the node level, similar to the node level integrity protection of XML Signature. For example, XML Access Control systems can restrict the read access to a particular node in an XML tree while allowing access to its child nodes. This thesis is focused on the development of a cryptography based system which can protect the confidentiality of arbitrary nodes in an XML tree. This goal is reached by combining a tree addressing scheme of databases with cryptographic mechanisms. This system is called “XML Pool Encryption”. To verify the results of this thesis, XML Pool Encryption has been implemented using the Java programming language.Die eXtensible Markup Language (XML) ist ein weit verbreitetes Format für Dokumente, die strukturierte Information enthalten. Strukturierte Information umfasst sowohl den eigentlichen Inhalt (z.B. Wörter, Bilder, etc.) sowie Auszeichnungsinformation, um die Rolle der Inhalte zu umschreiben, z.B. “Überschrift” oder “Preis”. XML bildet die Grundlage für eine große Anzahl existierender und im Entstehen begriffener Anwendungen, wie z.B. Vektorgrafik-Formate, Web Seiten, Enterprise Application Integration Systeme, Datenbank Schnittstellen oder Netzwerkprotokolle. Parallel zur steigenden Verbreitung von XML werden immer mehr Vorkehrungen zum Schutz der auf XML basierenden Systeme notwendig. Das World Wide Web Consortium (W3C) hat sich dieser Notwendigkeit angenommen, indem die “XML Signature Syntax and Processing” und die “XML Encryption Syntax and Processing” Empfehlungen verabschiedet wurden. Diese Standards definieren Mechanismen für Authentisierung, Integrität und Vertraulichkeit von XML Dokumenten. Die XML Signature Recommendation definiert einen Mechanismus, um beliebige Teile eines XML Dokumentes (Nodes) digital zu signieren. XML Signature kann sowohl Baumstrukturen als auch beliebig geformte Knotenmengen eines XML Baumes schützen. Die XML Encryption Recommendation definiert einen Mechanismus für das Verschlüsseln von Baumstrukturen innerhalb eines XML Dokumentes. W3C XML Encryption ist hierbei auf die Verschlüsselung kompletter Baumstrukturen beschränkt, d.h. es existiert keine Möglichkeit, die Vertraulichkeit für einzelne Knoten im Dokument zu gewährleisten, ohne dass die Kinder dieser Knoten ebenfalls geschützt werden. Für die Zugriffskontrolle von XML basierten Daten wurden Zugriffsschutzmodelle aus dem Datenbankbereich überarbeitet. Diese Systeme bieten die Durchsetzung fein granularer Zugriffskontrolle auf Knotenebene, ähnlich dem Integritätsschutz beliebiger Knoten bei XML Signature. So ist es beispielsweise möglich, den Lesezugriff auf einen Knoten zu verweigern, während die Kinder dieses Knotens weiterhin lesbar bleiben. Im Mittelpunkt dieser Arbeit steht die Entwicklung eines auf kryptografischen Verfahren basierenden Systems, welches die Vertraulichkeit für beliebige Knoten eines XML Baumes gewährleistet. Dieses Ziel wurde durch die Kombination eines Schemas für die Adressierung von Baumstrukturen mit kryptografischen Verfahren erreicht. Dieses System wird “XML Pool Encryption” genannt. Zur Überprüfung der Resultate dieser Arbeit wurde XML Pool Encryption in Java implementiert

ИНТЕЛЛЕКТУАЛЬНЫЕ МЕХАТРОННЫЕ СИСТЕМЫ С ДИСТАНЦИОННЫМ ВЗАИМОДЕЙСТВИЕМ КОМПОНЕНТОВ: СТРУКТУРА И ФУНКЦИИ

Basic requirements to sensor and controlling tracts of mechatronic systems with the remote organization of object control processes have been considered in the paper. A rational approach presupposes designing of the mentioned systems as multichannel technical complexes intended for parallel or quasi-parallel force-moment control of outlet mechanical links (motion modules) by multiple coordinates of the required phase space. It has been shown that the use of digitizing principles and distributed data procession in mechatronic systems makes it possible to pass to the unified structure and typical set of software and hardware functions of the aforesaid tracts. The paper gives consideration to a structural and functional scheme of the mechatronic system which contains an intellectual sensor device, a controlling center and an intellectual executive mechanism. The tasks that are linked with organization of preliminary information procession and construction of the systematic interface for transfer of telemetric transactions between controlled objects and the control center have been specified in the paper. Solution of a functionally full set of logically completed tasks is imposed to software and hardware tracts of the mechatronic system which is based on the abovementioned principles.The paper presents preliminary distribution of functions according to the system resources that is between an intellectual sensor unit, a control center and an intellectual executive mechanism. One of the most important features is an informational compatibility of the system components which is achieved owing to the use of unified transactions. The noise immune data coding expands useful informational transaction volume to some actual volume. It has been shown that construction of tract transfer and transaction reception in the intellectual mechatronic system on the basis of radio channels is considered as the most complicated technical solution. Проанализированы базовые требования, предъявляемые к сенсорным и управляющим трактам мехатронных систем с дистанционной организацией процессов контроля и управления объектами. Рациональным подходом является проектирование указанных систем как многоканальных технических комплексов, рассчитанных на параллельное или квазипараллельное силомоментное управление выходными механическими звеньями (модулями движения) по множеству координат требуемого фазового пространства. Показано, что применение в мехатронных системах принципов цифровизации и распределенной обработки данных позволяет перейти к унифицированной структуре и типовому набору функций аппаратных и программных средств указанных трактов.Рассмотрена структурно-функциональная схема мехатронной системы, содержащей интеллектуальное сенсорное устройство, центр управления и интеллектуальный исполнительный механизм. Специфицированы задачи, связанные с организацией предварительной обработки информации и построением системного интерфейса передачи телеметрических транзакций между контролируемыми объектами и центром управления. На аппаратные и программные средства трактов мехатронной системы, построенной на основе указанных принципов, возлагается решение функционально полного набора завершенных в логическом отношении задач.Представлено предварительное распределение функций по ресурсам системы – между интеллектуальным сенсорным устройством, центром управления и интеллектуальным исполнительным механизмом. Один из важнейших показателей – информационная совместимость составных частей системы – достигается за счет применения унифицированных транзакций. Помехоустойчивое кодирование данных расширяет полезный информационный объем транзакции до некоторого фактического объема. Показано, что наиболее сложным техническим решением является построение в интеллектуальной мехатронной системе трактов передачи и приема транзакций на основе радиоканалов.

Proceedings of the ECSCW'95 Workshop on the Role of Version Control in CSCW Applications

The workshop entitled "The Role of Version Control in Computer Supported Cooperative Work Applications" was held on September 10, 1995 in Stockholm, Sweden in conjunction with the ECSCW'95 conference. Version control, the ability to manage relationships between successive instances of artifacts, organize those instances into meaningful structures, and support navigation and other operations on those structures, is an important problem in CSCW applications. It has long been recognized as a critical issue for inherently cooperative tasks such as software engineering, technical documentation, and authoring. The primary challenge for versioning in these areas is to support opportunistic, open-ended design processes requiring the preservation of historical perspectives in the design process, the reuse of previous designs, and the exploitation of alternative designs. The primary goal of this workshop was to bring together a diverse group of individuals interested in examining the role of versioning in Computer Supported Cooperative Work. Participation was encouraged from members of the research community currently investigating the versioning process in CSCW as well as application designers and developers who are familiar with the real-world requirements for versioning in CSCW. Both groups were represented at the workshop resulting in an exchange of ideas and information that helped to familiarize developers with the most recent research results in the area, and to provide researchers with an updated view of the needs and challenges faced by application developers. In preparing for this workshop, the organizers were able to build upon the results of their previous one entitled "The Workshop on Versioning in Hypertext" held in conjunction with the ECHT'94 conference. The following section of this report contains a summary in which the workshop organizers report the major results of the workshop. The summary is followed by a section that contains the position papers that were accepted to the workshop. The position papers provide more detailed information describing recent research efforts of the workshop participants as well as current challenges that are being encountered in the development of CSCW applications. A list of workshop participants is provided at the end of the report. The organizers would like to thank all of the participants for their contributions which were, of course, vital to the success of the workshop. We would also like to thank the ECSCW'95 conference organizers for providing a forum in which this workshop was possible