71 results on '"Constantin, Catalin"'
Search Results
2. Model-Predictive Control for Omnidirectional Mobile Robots in Logistic Environments Based on Object Detection Using CNNs
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Stefan-Daniel Achirei, Razvan Mocanu, Alexandru-Tudor Popovici, and Constantin-Catalin Dosoftei
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Electrical and Electronic Engineering ,omnidirectional mobile robots ,object detection ,convolutional neural networks ,depth sensing ,computer vision ,discretized-time model ,predictive control algorithm ,navigation ,Biochemistry ,Instrumentation ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry - Abstract
Object detection is an essential component of autonomous mobile robotic systems, enabling robots to understand and interact with the environment. Object detection and recognition have made significant progress using convolutional neural networks (CNNs). Widely used in autonomous mobile robot applications, CNNs can quickly identify complicated image patterns, such as objects in a logistic environment. Integration of environment perception algorithms and motion control algorithms is a topic subjected to significant research. On the one hand, this paper presents an object detector to better understand the robot environment and the newly acquired dataset. The model was optimized to run on the mobile platform already on the robot. On the other hand, the paper introduces a model-based predictive controller to guide an omnidirectional robot to a particular position in a logistic environment based on an object map obtained from a custom-trained CNN detector and LIDAR data. Object detection contributes to a safe, optimal, and efficient path for the omnidirectional mobile robot. In a practical scenario, we deploy a custom-trained and optimized CNN model to detect specific objects in the warehouse environment. Then we evaluate, through simulation, a predictive control approach based on the detected objects using CNNs. Results are obtained in object detection using a custom-trained CNN with an in-house acquired data set on a mobile platform and in the optimal control for the omnidirectional mobile robot.
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- 2023
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3. Kinematics Calibration and Validation Approach Using Indoor Positioning System for an Omnidirectional Mobile Robot
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Alexandru-Tudor Popovici, Constantin-Catalin Dosoftei, and Cristina Budaciu
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Motion ,OMR ,indoor positioning system ,accurate localization ,calibration ,validation ,Calibration ,Robotics ,Electrical and Electronic Engineering ,Reactive Oxygen Species ,Biochemistry ,Instrumentation ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Biomechanical Phenomena - Abstract
Monitoring and tracking issues related to autonomous mobile robots are currently intensively debated in order to ensure a more fluent functionality in supply chain management. The interest arises from both theoretical and practical concerns about providing accurate information about the current and past position of systems involved in the logistics chain, based on specialized sensors and Global Positioning System (GPS). The localization demands are more challenging as the need to monitor the autonomous robot’s ongoing activities is more stringent indoors and benefit from accurate motion response, which requires calibration. This practical research study proposes an extended calibration approach for improving Omnidirectional Mobile Robot (OMR) motion response in the context of mechanical build imperfections (misalignment). A precise indoor positioning system is required to obtain accurate data for calculating the calibration parameters and validating the implementation response. An ultrasound-based commercial solution was considered for tracking the OMR, but the practical observed errors of the readily available position solutions requires special processing of the raw acquired measurements. The approach uses a multilateration technique based on the point-to-point distances measured between the mobile ultrasound beacon and a current subset of fixed (reference) beacons, in order to obtain an improved position estimation characterized by a confidence coefficient. Therefore, the proposed method managed to reduce the motion error by up to seven-times. Reference trajectories were generated, and robot motion response accuracy was evaluated using a Robot Operating System (ROS) node developed in Matlab-Simulink that was wireless interconnected with the other ROS nodes hosted on the robot navigation controller.
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- 2022
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4. Safety Solution Implementation for an Omnidirectional Autonomous Mobile Robot used in Logistics Systems
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Constantin-Catalin Dosoftei, Razvan Musteata, and Alexandru Tudor Popovici
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- 2022
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5. Learning PLC-based Automation by Using an Educational Elevator
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Georgel Gabor, Dumitru-Dorin Lucache, and Constantin-Catalin Dosoftei
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- 2022
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6. Asymptotically ideal Chinese remainder theorem ‐based secret sharing schemes for multilevel and compartmented access structures
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Constantin Catalin Dragan and Ferucio Laurenţiu Ţiplea
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Discrete mathematics ,TK7885-7895 ,Computer engineering. Computer hardware ,Ideal (set theory) ,Computer Networks and Communications ,Computer science ,Electronic computers. Computer science ,QA75.5-76.95 ,Chinese remainder theorem ,Secret sharing ,Software ,Information Systems - Abstract
Multilevel and compartmented access structures are two important classes of access structures where participants are grouped into levels/compartments with different degrees of trust and privileges. The construction of secret sharing schemes for such access structures has been the attention of researchers for a long time. Two main approaches have been taken so far, one of them is based on polynomial interpolation and the other one is based on the Chinese Remainder Theorem (CRT). In this article the first asymptotically ideal CRT‐based secret sharing schemes for (disjunctive, conjunctive) multilevel and compartmented access structures are proposed. Our approach is compositional and it is based on a variant of the Asmuth‐Bloom secret sharing scheme where some participants may have public shares. Based on this, the proposed secret sharing schemes for multilevel and compartmented access structures are asymptotically ideal if and only if they are based on 1‐compact sequences of co‐primes. Possible applications for secret image and multi‐secret sharing are pointed‐out.
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- 2021
7. Simulation Power vs. Immersive Capabilities: Enhanced Understanding and Interaction with Digital Twin of a Mechatronic System
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Constantin-Catalin Dosoftei
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Fluid Flow and Transfer Processes ,Process Chemistry and Technology ,General Engineering ,General Materials Science ,digital twin ,mechatronic system ,virtual commissioning ,mixed reality ,cyber-physical system ,Instrumentation ,Computer Science Applications - Abstract
Automation Studio, a specialised simulation software, offers virtual commissioning capabilities and robust tools for modelling the behaviour and performance of a pneumatic robot controlled by a PLC. Conversely, Unity is a versatile platform primarily used for creating high-quality 3D games and interactive simulations, providing immersive experiences with DTs through mixed-reality environments. This paper provides a study that compares and contrasts the simulation power of Automation Studio and the immersive capabilities of Unity in the context of developing digital twins for a mechatronic system. This research explores how these complementary approaches enhance the development, validation, understanding, and interaction with digital twins. By examining both platforms in this context, the article provides valuable insights for engineers, developers, and researchers looking to create digital twins for mechatronic systems, but not only. This study demonstrates the potential of leveraging the combined power of simulation and immersive capabilities to improve the interaction between the real robotic arm manipulator cylindrical type and its digital twin in different scenarios, using an OPC approach for mirroring. The combination of Automation Studio and Unity provides a powerful platform for applied science education in the field of the digital twin of mechatronic systems.
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- 2023
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8. Pulsed laser deposited V2O3 thin-films on graphene/aluminum foil for micro-battery applications
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Teddy Tite, Cosmin Ungureanu, Mihaela Buga, Ionel Stavarache, Elena Matei, Constantin Catalin Negrila, Lucian Trupina, Adnana Spinu-Zaulet, and Aurelian Catalin Galca
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General Chemical Engineering ,Electrochemistry ,Analytical Chemistry - Published
- 2023
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9. Pulsed Laser Deposited Vanadium Sesquioxide Thin Films on Graphene/Aluminium Foil for Battery Applications
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Teddy TITE, Cosmin UNGUREANU, Mihaela BUGA, Ionel STAVARACHE, Elena Matei, Constantin Catalin NEGRILA, Lucian TRUPINA, Adnana SPINU-ZAULET, and Aurelian Catalin Galca
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
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10. Machine-Checked Proofs of Privacy Against Malicious Boards for Selene & Co
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Constantin Catalin Dragan, Francois Dupressoir, Ehsan Estaji, Kristian Gjosteen, Thomas Haines, Peter Y.A. Ryan, Peter B. Ronne, Morten Rotvold Solberg, University of Surrey (UNIS), University of Bristol [Bristol], University of Luxembourg [Luxembourg], NTNU Samfunnsforskning AS / NTNU Social Research, Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU)-Norwegian University of Science and Technology (NTNU), Australian National University (ANU), Proof techniques for security protocols (PESTO), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Department of Formal Methods (LORIA - FM), Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and ANR-22-PECY-0006,SVP,Verification of Security Protocols(2022)
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[INFO.INFO-CR]Computer Science [cs]/Cryptography and Security [cs.CR] - Abstract
International audience; Privacy is a notoriously difficult property to achieve in complicated systems and especially in electronic voting schemes. Moreover, electronic voting schemes is a class of systems that require very high assurance. The literature contains a number of ballot privacy definitions along with security proofs for common systems. Some machine-checked security proofs have also appeared. We define a new ballot privacy notion that captures a larger class of voting schemes. This notion improves on the state of the art by taking into account that verification in many schemes will happen or must happen after the tally has been published, not before as in previous definitions. As a case study we give a machine-checked proof of privacy for Selene, which is a remote electronic voting scheme which offers an attractive mix of security properties and usability. Prior to our work, the computational privacy of Selene has never been formally verified. Finally, we also prove that MiniVoting and Belenios satisfies our definition.
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- 2022
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11. Real-Time Motion Control of an Electric Driven OMR using a ROS to Matlab Bridged Approach
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Petru-Razvan Sacaleanu, Alexandru-Tudor Popovici, Constantin-Catalin Dosoftei, and Cristina Budaciu
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Indoor positioning system ,Computer science ,Supply chain ,Real-time computing ,Robot ,Mobile robot ,Motion planning ,Motion control ,MATLAB ,Omnidirectional antenna ,computer ,computer.programming_language - Abstract
The ability to remotely monitor and track the location of autonomous mobile robots assures more control to the logistics companies, which guarantees the supply chain management is more efficient and secure. Therefore, many efforts and studies are focused on providing information about the current and past position of systems involved in the logistics chain, through the use of sensors and GPS-like systems. In recent years, Omnidirectional Mobile Robots are increasingly involved in complex industrial environments due to their navigation capabilities for complex trajectory planning together with task assignments.This paper presents an evaluation study of integrated development for an Omnidirectional Mobile Robot that is designed to serve in a dynamic logistic environment using Marvelmind Indoor Positioning System. The overall supervised system can be efficiently developed using Robot Operating System nodes, the path planning nodes benefiting from using Matlab-Simulink. This paper relates the work-in-progress of a real omnidirectional mobile robots (OMRs) platform subject to indoor localization with Marvelmind IPS network. This study emphasizes the need for consistent data taken from the sensors placed on the robot, the validation being a very important step for accurate robot localization.
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- 2021
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12. Mechanised Models and Proofs for Distance-Bounding
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Constantin Catalin Dragan, François Dupressoir, Pascal Lafourcade, Ioana Boureanu, and David Gerault
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Theoretical computer science ,Computer science ,business.industry ,Cryptography ,Gas meter prover ,Mathematical proof ,Payment terminal ,law.invention ,Relay ,law ,Bounding overwatch ,Encoding (memory) ,business ,Protocol (object-oriented programming) - Abstract
In relay attacks, a man-in-the-middle adversary impersonates a legitimate party and makes it this party appear to be of an authenticator, when in fact they are not. In order to counteract relay attacks, distance-bounding protocols provide a means for a verifier (e.g., an payment terminal) to estimate his relative distance to a prover (e.g., a bankcard). We propose FlexiDB, a new cryptographic model for distance bounding, parameterised by different types of fine-grained corruptions. FlexiDB allows to consider classical cases but also new, generalised corruption settings. In these settings, we exhibit new attack strategies on existing protocols. Finally, we propose a proof-of-concept mechanisation of FlexiDB in the interactive cryptographic prover EasyCrypt. We use this to exhibit a flavour of man-in-the-middle security on a variant of MasterCard’s contactless-payment protocol.
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- 2021
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13. Hardware in the Loop Topology for an Omnidirectional Mobile Robot Using Matlab in a Robot Operating System Environment
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Alexandru-Tudor Popovici, Constantin-Catalin Dosoftei, Cristina Budaciu, Petru-Razvan Sacaleanu, and Paul-Marcelin Gherghel
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logistic robot ,omnidirectional mobile robot ,kinematic model ,symmetrical configuration ,hardware in the loop ,navigation ,ROS environment ,0209 industrial biotechnology ,Physics and Astronomy (miscellaneous) ,Computer science ,General Mathematics ,media_common.quotation_subject ,Real-time computing ,02 engineering and technology ,Interoperation ,020901 industrial engineering & automation ,Software ,0202 electrical engineering, electronic engineering, information engineering ,Computer Science (miscellaneous) ,QA1-939 ,Motion planning ,Omnidirectional antenna ,media_common ,business.industry ,Hardware-in-the-loop simulation ,Mobile robot ,Debugging ,Chemistry (miscellaneous) ,Robot ,020201 artificial intelligence & image processing ,business ,Mathematics - Abstract
The symmetry of the omnidirectional robot motion abilities around its central vertical axis is an important advantage regarding its driveability for the flexible interoperation with fixed conveyor systems. The paper illustrates a Hardware in the Loop architectural approach for integrated development of an Ominidirectional Mobile Robot that is designed to serve in a dynamic logistic environment. Such logistic environments require complex algorithms for autonomous navigation between different warehouse locations, that can be efficiently developed using Robot Operating System nodes. Implementing path planning nodes benefits from using Matlab-Simulink, which provides a large selection of algorithms that are easily integrated and customized. The proposed solution is deployed for validation on a NVIDIA Jetson Nano, the embedded computer hosted locally on the robot, that runs the autonomous navigation software. The proposed solution permits the live connection to the omnidirectional prototype platform, allowing to deploy algorithms and acquire data for debugging the location, path planning and the mapping information during real time autonomous navigation experiments, very useful in validating different strategies.
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- 2021
14. Bulk and surface characteristics of co-electrodeposited Cu2FeSnS4 thin films sulfurized at different annealing temperatures
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Outman El Khouja, Constantin Catalin Negrila, Khalid Nouneh, Mihail Secu, Mohamed Ebn Touhami, Elena Matei, Viorica Stancu, Monica Enculescu, Victor Kuncser, and Aurelian Catalin Galca
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Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys - Published
- 2022
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15. Implementation of a Virtual Control Lab to Support Teaching in Engineering Control
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Constantin-Catalin Dosoftei and Andreea-Elena Cojocaru
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Workstation ,business.industry ,Process (engineering) ,Computer science ,020209 energy ,020208 electrical & electronic engineering ,02 engineering and technology ,Solid modeling ,Automation ,Bridge (nautical) ,law.invention ,Engineering management ,Software ,Engineering education ,law ,Component (UML) ,0202 electrical engineering, electronic engineering, information engineering ,business - Abstract
Because engineering is a practicing profession, laboratory experiments are considered to be an imperative component of engineering curricula by all stakeholders involved in the education process. Therefore, virtual and remote laboratories represent unique solutions to support teaching activities in online learning from the actual condition of the 2020 year. This paper describes a case study of implementation for a virtual twin of a pneumatic workstation using facilities offered by Automation StudioTM software. The challenges and opportunities from engineering education make from the virtual lab a bridge to Industry 4.0 paradigms, reaching superior modelling and simulation techniques. Furthermore, this paper highlights some advantages of approaching virtual experiments over real ones.
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- 2020
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16. Integrated Learning in Electrical and Control Engineering Using an Educational Elevator System
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Georgel Gabor, Constantin-Catalin Dosoftei, and Dorin Dumitru Lucache
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Elevator ,business.industry ,Computer science ,020209 energy ,020208 electrical & electronic engineering ,Control (management) ,Programmable logic controller ,Control engineering ,02 engineering and technology ,Software ,SCADA ,Multidisciplinary approach ,0202 electrical engineering, electronic engineering, information engineering ,Inverter ,business ,Encoder - Abstract
The research of the authors is focused on presenting a practical multidisciplinary experiment - an elevator simulator to relate theory and practice inside of a lot of disciplines and to bring the “real world” into a useful case study for electrical and control engineering education. Through the existence of interesting experiments, students gain motivation either to continue thinking and improving new solutions for building and control of elevators. The concept of the modern elevator is presented in this paper from the perspective of integration of current technological equipment like a programmable logic controller, inverter, encoder, human-machine-interface on which students can develop various control strategies using a SCADA system. The paper presents the some exercises that students can perform on the existent simulator.
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- 2020
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17. On the asymptotic idealness of the Asmuth-Bloom threshold secret sharing scheme
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Constantin Catalin Dragan and Ferucio Laurentiu Tiplea
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Scheme (programming language) ,Information Systems and Management ,Theoretical computer science ,Fundamental theorem ,business.industry ,Computer science ,020206 networking & telecommunications ,Cryptography ,02 engineering and technology ,Secret sharing ,Computer Science Applications ,Theoretical Computer Science ,Number theory ,Artificial Intelligence ,Control and Systems Engineering ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Ideal (order theory) ,business ,computer ,Chinese remainder theorem ,Software ,Computer Science::Cryptography and Security ,computer.programming_language - Abstract
The Chinese remainder theorem (CRT) is a fundamental theorem in number theory, widely used in cryptography to design secret sharing schemes. The CRT-based secret sharing schemes proposed so far make use of sequences of pairwise co-prime integers with special properties. The way these sequences are chosen plays a crucial role in the security achieved by the schemes that rely on them. Moreover, the CRT-based secret sharing schemes could achieve at most asymptotic idealness. In this paper we prove that the Asmuth-Bloom threshold secret sharing scheme is asymptotic ideal if and only if it is based on 1-compact sequences of co-primes. Apart from this, a comprehensive analysis of the known variants of the Asmuth-Bloom threshold secret sharing scheme is provided, clarifying the security properties achieved by each of them.
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- 2018
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18. An X-ray photoelectron spectroscopy depth profile study on the InGeNi/(110) cleaved GaAs structure
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R. V. Ghita, Costel Cotirlan, Constantin Catalin Negrila, M. F. Lazarescu, and Constantin Logofatu
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010302 applied physics ,Materials science ,business.industry ,Mechanical Engineering ,Schottky barrier ,Analytical chemistry ,Schottky diode ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Evaporation (deposition) ,Semiconductor ,X-ray photoelectron spectroscopy ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,business ,Ohmic contact ,Single crystal ,Diode - Abstract
InGeNi ohmic contacts on n-type semi-insulating GaAs(110) cleaved surfaces were fabricated. Cleaving semiconductor single crystal ensures the obtaining of semiconductor surfaces almost ideal in terms of chemical purity and stoichiometry. The chemical depth profile of metallic layer was investigated and revealed through multiple alternating steps of Ar+ etchings and XPS (x-ray photoelectron spectroscopy) measurements. The metallic layers made of alloy of Ge, In and Ni (60 nm Ge, 60 nm In and 10 nm Ni), were obtained by thermal evaporation on cleaved surfaces in a high vacuum facility, followed by a thermal annealing at 430–450 °C for 5 min. Twelve etching sessions were required until the metal/semiconductor interface has been reached. A total of 14 etchings steps were performed during the experiment, a layer with a thickness of 140 nm being removed from the surface. The atomic concentrations of the constituent chemical elements were determined. In3d, In4d, Ga3d, Ga2p, As3d, As2p, Ni2p3/2, Ge3d, O1s and C1s spectral lines were recorded and chemical bonds within the layer were analyzed from the fittings. The formation of InxGa1-xAs type compounds and of an intermediate semiconductor layer rich in Ge atoms at the interface was highlighted. X-ray detectors InGeNi/GaAs/Al and InGeNi/GaAs/Ti were fabricated with ohmic contacts based on this contacting scheme and Schottky interfaces prepared also by evaporation on cleaved edges. Electrical characteristics have been investigated and key diode parameters determined ─ ideality factor, Schottky barrier height, series resistance. Detection capabilities of these devices were studied in an x-rays flux, provided by a Co anode x-ray source.
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- 2018
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19. KYChain: User-Controlled KYC Data Sharing and Certification
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Mark Manulis and Constantin Catalin Dragan
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FOS: Computer and information sciences ,Computer Science - Cryptography and Security ,Know your customer ,Computer science ,business.industry ,Internet privacy ,020207 software engineering ,02 engineering and technology ,Certification ,Data sharing ,020204 information systems ,Ledger ,0202 electrical engineering, electronic engineering, information engineering ,Identity (object-oriented programming) ,Confidentiality ,business ,Cryptography and Security (cs.CR) ,Risk management - Abstract
Under Know Your Customer (KYC) regulations, financial institutions are required to verify the identity and assess the trustworthiness of any new client during on-boarding, and maintain up-to-date records for risk management. These processes are time consuming, expensive, typically have sub-par record-keeping steps, and disadvantage clients with nomad lifestyle. In this paper, we introduce KYChain as a privacy-preserving certification mechanism that allows users to share (certified) up-to-date KYC data across multiple financial institutions. We base KYChain on immutable ledgers and show that it offers confidentiality and certification compliance of KYC data.
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- 2020
20. Computer Security
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Roger Hallman and Constantin Catalin Dragan
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- 2020
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21. Biometric-Authenticated Searchable Encryption
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Mark Manulis, Constantin Catalin Dragan, and Daniel Gardham
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Scheme (programming language) ,050101 languages & linguistics ,Biometrics ,Keyword search ,business.industry ,Computer science ,InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,Data_MISCELLANEOUS ,05 social sciences ,02 engineering and technology ,Computer security ,computer.software_genre ,Encryption ,Secret sharing ,Outsourcing ,Data_FILES ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,0501 psychology and cognitive sciences ,Biometric data ,business ,computer ,computer.programming_language - Abstract
We introduce Biometric-Authenticated Keyword Search (BAKS), a novel searchable encryption scheme that relieves clients from managing cryptographic keys and relies purely on client’s biometric data for authenticated outsourcing and retrieval of files indexed by encrypted keywords.
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- 2020
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22. Towards end-to-end verifiable online voting: adding verifiability to established voting systems
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Alsadi, Mohammed, Casey, Matthew, Dragan, Constantin Catalin, Dupressoir, Francois, Riley, Luke, Sallal, Muntadher, Schneider, Steve, Treharne, Helen, Wadsworth, Joe, and Wright, Phil
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FOS: Computer and information sciences ,Computer Science - Cryptography and Security ,ComputingMilieux_LEGALASPECTSOFCOMPUTING ,Cryptography and Security (cs.CR) - Abstract
Online voting for independent elections is generally supported by trusted election providers. Typically these providers do not offer any way in which a voter can verify their vote, so the providers are trusted with ballot privacy and ensuring correctness. Despite the desire to offer online voting for political elections, this lack of transparency and verifiability is often seen as a significant barrier to the large-scale adoption of online elections. Adding verifiability to an online election increases transparency and integrity, allowing voters to verify that their vote has been recorded correctly and included in the tally. However, replacing existing online systems with those that provide verifiable voting requires new algorithms and code to be deployed, and this presents a significant business risk to commercial election providers. In this paper we present the first step in an incremental approach which minimises the business risk but demonstrates the advantages of verifiability, by developing an implementation of key elements of a Selene-based verifiability layer and adding it to an operational online voting system. Selene is a verifiable voting protocol that uses trackers to enable voters to confirm that their votes have been captured correctly while protecting voter anonymity. This results in a system where even the election authority running the system cannot change the result in an undetectable way, and gives stronger guarantees on the integrity of the election than were previously present. We explore the challenges presented by adding a verifiability layer to an operational system. We describe the results of two initial trials, which obtained that survey respondents found this form of verifiability easy to use and that they broadly appreciated it. We conclude by outlining the further steps in the road-map towards the deployment of a fully trustworthy online voting system., 30 pages
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- 2019
23. Real-time Communication between Automation Studio and PLC based on OPC Technology for control 3-DoF robot
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Constantin-Catalin Dosoftei, Lucian Mastacan, and Alexandru Lupu
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010302 applied physics ,Ethernet ,Open platform ,business.industry ,OLE for Process Control ,Computer science ,Real-time communication ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Automation ,Programmable logic device ,Software ,Supervisory control ,Embedded system ,0103 physical sciences ,Robot ,0210 nano-technology ,business - Abstract
The approach from this work is multidisciplinary, similar with challenges from industrial word which started to implement the new industrial revolution in more and more areas. This paper presents a method of implementing a remote real-time communication, based on Open Platform Communication (OPC) on the Ethernet, for the communication between Automation Studio software solution and a Programmable Logic Computer (PLC) which control a 3-DoF pneumatic robot with a handle gripper. The model of robot is implemented in Automation Studio and this paper uses the benefits of OPC Server in order to connect the simulated system with a PLC. A real PLC is used to implement the supervisory control of the simulated plant. Relation between the physical and the virtual world is an important component of Industry 4.0, represent cyber-physical system.
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- 2019
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24. Photoluminescence and structural properties of the nitrogen doped TiO
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Andreea, Nila, Mihaela, Baibarac, Adelina, Udrescu, Ion, Smaranda, Alice, Mateescu, Gheorghe, Mateescu, Paul, Mereuta, and Constantin Catalin, Negrila
- Abstract
Mixtures of nitrogen-doped titanium dioxide (TiO
- Published
- 2019
25. A Combined Model and Data-Driven Approach for the Determination of Rotor Temperature in an Induction Machine
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Constantin-Catalin Dosoftei, Alexandru Onea, and Razvan Mocanu
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0209 industrial biotechnology ,Stator ,Powertrain ,Computer science ,TP1-1185 ,02 engineering and technology ,Biochemistry ,Article ,Analytical Chemistry ,law.invention ,020901 industrial engineering & automation ,law ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Instrumentation ,Nonlinear autoregressive exogenous model ,AC machines ,Rotor (electric) ,Chemical technology ,020208 electrical & electronic engineering ,Temperature ,neural network applications ,Function (mathematics) ,fault diagnosis ,Atomic and Molecular Physics, and Optics ,Nonlinear system ,Autoregressive model ,Particle filter ,recursive estimation - Abstract
The need for protection of electrical machines comes as a demand of safety regulations in the automotive industry as well as a result of the general desire to obtain a robust and reliable electric powertrain. This paper introduces a hybrid method for estimating the temperature of the rotor of an Induction Machine (IM) based on a Nonlinear Autoregressive Network with Exogenous inputs (NARX) used as a prediction function within a particle filter. The temperature of the stator case is measured, and the information is used as an input to a NARX network and as a variable to a thermal process with first-order dynamics which serves as an observation function. Uncertainties of the NARX and thermal model are determined and used to correct the posterior estimate. Experimental data are used from a real IM test-bench and the results prove the applicability and good performance.
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- 2021
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26. Structural, morphological and optical properties of Cu–Fe–Sn–S thin films prepared by electrodeposition at fixed applied potential
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Outman El Khouja, Lucian Pintilie, Mhamed Taibi, Khalid Nouneh, Monica Enculescu, Mohamed Ebn Touhami, Elena Matei, Aurelian Catalin Galca, Constantin Catalin Negrila, and M.Y. Zaki
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010302 applied physics ,Materials science ,Metals and Alloys ,Energy-dispersive X-ray spectroscopy ,Analytical chemistry ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,symbols.namesake ,X-ray photoelectron spectroscopy ,0103 physical sciences ,Materials Chemistry ,symbols ,Diffuse reflection ,Cyclic voltammetry ,Thin film ,0210 nano-technology ,Spectroscopy ,Raman spectroscopy - Abstract
Cu–Fe–Sn–S films were obtained on indium tin oxide / glass substrates by a low-cost electrodeposition using an aqueous solution of CuSO4, FeSO4, SnSO4, and Na2S2O3 at room temperature followed by high-temperature sulfurization (500 °C) in argon flow. A range of cathodic potentials have been used for electrodeposition, those being chosen after a preliminary cyclic voltammetry study. The coatings were characterized using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray Photoelectron Spectroscopy and conventional spectroscopy (diffuse reflectance and specular transmission). The results are discussed with respect to the used applied potential.
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- 2021
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27. Distributive weighted threshold secret sharing schemes
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Constantin Catalin Dragan and Ferucio Laurentiu Tiplea
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Discrete mathematics ,Information Systems and Management ,020206 networking & telecommunications ,0102 computer and information sciences ,02 engineering and technology ,01 natural sciences ,Secret sharing ,Computer Science Applications ,Theoretical Computer Science ,Combinatorics ,Distributive property ,010201 computation theory & mathematics ,Artificial Intelligence ,Control and Systems Engineering ,0202 electrical engineering, electronic engineering, information engineering ,Entropy (information theory) ,Chinese remainder theorem ,Software ,Access structure ,Mathematics - Abstract
The concept of distributive weighted threshold access structure is introduced, which is an weighted threshold access structure where the participants are distributed on levels, the participants on the same level are assigned the same weight, and the threshold of the access structure is 1. The weight of the participants on the ith level is of the form 1/ki and, therefore, the ith level induces a standard threshold access structure with threshold ki.We propose a CRT-based realization of distributive weighted threshold access structures, which is asymptotically perfect and perfect zero-knowledge. We also show that distributive weighted threshold access structures do not generally have ideal realizations. In case of just one level, our scheme can be viewed as an asymptotically perfect and perfect zero-knowledge variation of the Asmuth-Bloom secret sharing scheme.
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- 2016
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28. Investment: What holds Romanian firms back?
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Pal, Rozalia, Wruuck, Patricia, Stamate, Amalia, and Dumitrescu, Constantin Catalin
- Subjects
ddc:330 - Abstract
In Romania, the share of firms carrying out investment is amongst the lowest in the European Union. This is despite strong economic growth in recent years and persistent needs for upgrading the capital stock in the country. This paper draws on information from two surveys - the EIB Investment Survey and a survey on access to finance conducted by the National Bank of Romania - to analyse the reasons for this subdued corporate investment activity. It also contributes to the debate on why investment in central, eastern and south eastern Europe has remained relatively subdued after the crisis.
- Published
- 2019
29. Private Votes on Untrusted Platforms: Models, Attacks and Provable Scheme
- Author
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Constantin Catalin Dragan, Steve Kremer, Sergiu Bursuc, Proof techniques for security protocols (PESTO), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Department of Formal Methods (LORIA - FM), Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and University of Surrey (UNIS)
- Subjects
Scheme (programming language) ,Computer science ,Electronic voting ,media_common.quotation_subject ,05 social sciences ,Computational indistinguishability ,020206 networking & telecommunications ,02 engineering and technology ,Cryptographic protocol ,Computer security model ,16. Peace & justice ,computer.software_genre ,Computer security ,Automated theorem proving ,[INFO.INFO-CR]Computer Science [cs]/Cryptography and Security [cs.CR] ,Voting ,0202 electrical engineering, electronic engineering, information engineering ,Malware ,0501 psychology and cognitive sciences ,computer ,050104 developmental & child psychology ,media_common ,computer.programming_language - Abstract
International audience; Modern e-voting systems deploy cryptographic protocols on a complex infrastructure involving different computing platforms and agents. It is crucial to have appropriate specification and evaluation methods to perform rigorous analysis of such systems, taking into account the corruption and computational capabilities of a potential attacker. In particular, the platform used for voting may be corrupted, e.g. infected by malware, and we need to ensure privacy and integrity of votes even in that case. We propose a new definition of vote privacy, formalized as a computational indistinguishability game, that allows to take into account such refined attacker models; we show that the definition captures both known and novel attacks against several voting schemes; and we propose a scheme that is provably secure in this setting. We moreover formalize and machine-check the proof in the EasyCrypt theorem prover.
- Published
- 2019
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30. Temperature Fuzzy Control System with Mamdani Controller
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Constantin-Catalin Dosoftei and Lucian Mastacan
- Subjects
0209 industrial biotechnology ,Computer science ,020209 energy ,Control (management) ,02 engineering and technology ,Fuzzy control system ,Linear interpolation ,Fuzzy logic ,020901 industrial engineering & automation ,Operator (computer programming) ,Control theory ,Lookup table ,0202 electrical engineering, electronic engineering, information engineering ,Table (database) - Abstract
Implementing a fuzzy logic controller with Iookup table (FLC-LT) for a qualified operator is an easy task. Good performance for a fuzzy control system with FLC-LT are difficult to achieve due to the reduced number of fuzzy control values that can be introduced in a lookup table. Starting from the authors’ previous achievements, regarding the implementation of FLC-LT with linear interpolation in two lookup tables, one for a coarse control and another one for a fine control, the paper presents a method of increasing the fuzzy control performance by introducing in the PI-like fuzzy control algorithm a fuzzy coefficient to adjust the output command change of the FLC-LT. The method is validated by the best performance of a temperature fuzzy control system.
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- 2018
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- View/download PDF
31. Machine-checked proofs for electronic voting: privacy and verifiability for Belenios
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Constantin Catalin Dragan, Bogdan Warinschi, Véronique Cortier, François Dupressoir, Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria), Proof techniques for security protocols (PESTO), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Department of Formal Methods (LORIA - FM), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), University of Surrey (UNIS), University of Bristol [Bristol], European Project: 645865,H2020 ERC,ERC-2014-CoG,SPOOC(2015), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), and Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Protocol (science) ,Security analysis ,Computer science ,Electronic voting ,business.industry ,media_common.quotation_subject ,Cryptography ,0102 computer and information sciences ,02 engineering and technology ,16. Peace & justice ,Mathematical proof ,Computer security ,computer.software_genre ,01 natural sciences ,Registration authority ,[INFO.INFO-CR]Computer Science [cs]/Cryptography and Security [cs.CR] ,Ballot ,010201 computation theory & mathematics ,Voting ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,business ,computer ,media_common - Abstract
International audience; We present a machine-checked security analysis of Belenios-a deployed voting protocol used already in more than 200 elections. Belenios extends Helios with an explicit registration authority to obtain eligibility guarantees. We offer two main results. First, we build upon a recent framework for proving ballot privacy in EasyCrypt. Inspired by our application to Belenios, we adapt and extend the privacy security notions to account for protocols that include a registration phase. Our analysis identifies a trust assumption which is missing in the existing (pen and paper) analysis of Belenios: ballot privacy does not hold if the registrar misbehaves, even if the role of the registrar is seemingly to provide eligibility guarantees. Second, we develop a novel framework for proving strong verifiability in EasyCrypt and apply it to Belenios. In the process, we clarify several aspects of the pen-and-paper proof, such as how to deal with revote policies. Together, our results yield the first machine-checked analysis of both ballot privacy and verifiability properties for a deployed electronic voting protocol. Perhaps more importantly, we identify several issues regarding the applicability of existing definitions of privacy and verifiability to systems other than Helios. While we show how to adapt the definitions to the particular case of Belenios, our findings indicate the need for more general security notions for electronic voting protocols with registration authorities.
- Published
- 2018
32. Bootstrapping Online Trust: Timeline Activity Proofs
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Mark Manulis and Constantin Catalin Dragan
- Subjects
Service (systems architecture) ,Information retrieval ,Trustworthiness ,Computer science ,Bootstrapping (linguistics) ,Social media ,Timeline ,Static data ,Mathematical proof - Abstract
Establishing initial trust between a new user and an online service, is being generally facilitated by centralized social media platforms, i.e., Facebook, Google, by allowing users to use their social profiles to prove “trustworthiness” to a new service which has some verification policy with regard to the information that it retrieves from the profiles. Typically, only static information, e.g., name, age, contact details, number of friends, are being used to establish the initial trust. However, such information provides only weak trust guarantees, as (malicious) users can trivially create new profiles and populate them with static data fast to convince the new service. We argue that the way the profiles are used over (longer) periods of time should play a more prominent role in the initial trust establishment. Intuitively, verification policies, in addition to static data, could check whether profiles are being used on a regular basis and have a convincing footprint of activities over various periods of time to be perceived as more trustworthy. In this paper, we introduce Timeline Activity Proofs (TAP) as a new trust factor. TAP allows online users to manage their timeline activities in a privacy-preserving way and use them to bootstrap online trust, e.g., as part of registration to a new service. In our model we do not rely on any centralized social media platform. Instead, users are given full control over the activities that they wish to use as part of TAP proofs. A distributed public ledger is used to provide the crucial integrity guarantees, i.e., that activities cannot be tampered with retrospectively. Our TAP construction adopts standard cryptographic techniques to enable authorized access to encrypted activities of a user for the purpose of policy verification and is proven to provide data confidentiality protecting the privacy of user’s activities and authenticated policy compliance protecting verifiers from users who cannot show the required footprint of past activities.
- Published
- 2018
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- View/download PDF
33. Surface Modification of III-V Compounds Substrates for Processing Technology
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R. V. Ghita, Costel Cotirlan-Simioniuc, Lucian Trupina, Constantin Logofatu, and Constantin-Catalin Negrila
- Subjects
010302 applied physics ,Materials science ,0103 physical sciences ,Inorganic chemistry ,Surface modification ,02 engineering and technology ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences - Published
- 2017
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34. Machine-Checked Proofs of Privacy for Electronic Voting Protocols
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Benedikt Schmidt, Pierre-Yves Strub, François Dupressoir, Véronique Cortier, Constantin Catalin Dragan, Bogdan Warinschi, Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Proof techniques for security protocols (PESTO), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Department of Formal Methods (LORIA - FM), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), University of Surrey (UNIS), Institute IMDEA Software [Madrid], Google Inc, Research at Google, Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), University of Bristol [Bristol], Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Protocol (science) ,Information privacy ,Theoretical computer science ,business.industry ,Computer science ,Electronic voting ,media_common.quotation_subject ,020206 networking & telecommunications ,02 engineering and technology ,Encryption ,Mathematical proof ,Computer security ,computer.software_genre ,Public-key cryptography ,Automated theorem proving ,[INFO.INFO-CR]Computer Science [cs]/Cryptography and Security [cs.CR] ,Ballot ,Voting ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,business ,computer ,media_common - Abstract
International audience; We provide the first machine-checked proof of privacy-related properties (including ballot privacy) for an electronic voting protocol in the computational model. We target the popular Helios family of voting protocols, for which we identify appropriate levels of abstractions to allow the simplification and convenient reuse of proof steps across many variations of the voting scheme. The resulting framework enables machine-checked security proofs for several hundred variants of Helios and should serve as a stepping stone for the analysis of further variations of the scheme. In addition, we highlight some of the lessons learned regarding the gap between pen-and-paper and machine-checked proofs, and report on the experience with formalizing the security of protocols at this scale.
- Published
- 2017
- Full Text
- View/download PDF
35. Influence of boric acid concentration on the properties of electrodeposited CZTS absorber layers
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Lucian Pintilie, Khalid Nouneh, M. Burdusel, Elena Matei, M.Y. Zaki, Mihaela Baibarac, Aurelian Catalin Galca, M. Ebn Touhami, Constantin Catalin Negrila, and Petre Badica
- Subjects
Boric acid ,chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,engineering ,CZTS ,Kesterite ,engineering.material ,Condensed Matter Physics ,Mathematical Physics ,Atomic and Molecular Physics, and Optics - Published
- 2020
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36. Analysis of the Accuracy and Robustness of Kinect Sensor Used with the Scope of Robot Manipulation
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Ionel Staretu and Constantin Catalin Moldovan
- Subjects
Engineering ,business.industry ,Motion detection ,Robotics ,General Medicine ,computer.software_genre ,Object detection ,Visualization ,Virtual machine ,Robustness (computer science) ,Robot ,Computer vision ,Artificial intelligence ,business ,computer ,Gesture - Abstract
This paper describes in details the evaluation procedure developed in this paper for the measurement of the Kinect sensors accuracy and robustness in the detection process of the user hand and recognizing human hand gestures. Furthermore, the results are transferred to a robotic gripper in virtual environment for visualization. The research started with consideration on the current state of the methods and sensors used for the detection of the hand gestures. It was seen that the detection of human hand and gestures recognition represent an important research study in the field of robotics controls and automation. Through the time, different methods [7, 13] and sensors [12] were developed for the action of detection which became, with the passing of time, better and better, reaching today, a point, when Kinect sensor was constructed as a combination between mature sensor technology and efficient algorithms for detection. The goal of this paper is represented by the analysis, if the XBox 360 (TM) Kinect sensor, developed by Microsoft, is accurate enough to be used as a mean to control a robotic hand in virtual environment. To find this out, the main objectives of this paper represents the measurement of the accuracy of Kinect sensor action for the capture of gestures performed by a human hand in a repeatable manner. As a second objective, in order to be able to visualize the result, the gestures are translated into virtual environment. In order achieve the main scope of this paper, two metrics were defined, according to ISO standard for measurement. Those are: Accuracy/Precision using ISO 5725: 1994 [16] Repeatability - ISO 21748: 2010 [17] The result of the captured hand posture with the highest accuracy are then moved to a robotic hand simulated in virtual environment executing an object grasping and releasing.
- Published
- 2014
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37. A new approach to create a realistic virtual model of a cylindrical robot using Automation Studio
- Author
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A Lupu, Constantin-Catalin Dosoftei, and Carlos Pascal
- Subjects
Computer science ,business.industry ,media_common.quotation_subject ,Animation ,Mechatronics ,Automation ,Predictive maintenance ,Field (computer science) ,Software ,Debugging ,Robot ,Software engineering ,business ,media_common - Abstract
Industry 4.0 is mainly represented by the digitalization technologies of physical industrial assets, thus obtaining the cyber-physical systems. A key role in digitalization developing is indeed played by possibility to develop a realistic virtual model (3D model) and using this model in virtual simulations to test the functionality of the system at possible scenarios from real world. The paper presents the modelling a mechatronic system represented by a three-dimensional cylindrical type manipulator in Automation Studio software and aims creating cinematic animation which will be used in the field of virtual commissioning. This approach in Industry 4.0 paradigm is studied in the academic environment and in the industrial research from last decade time, because generate major benefits such as in remote accessibility for learning, time efficiency from planning to real setup with possibility of detection and debugging of errors in the system, for minimizing time commissioning and predictive maintenance.
- Published
- 2019
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- View/download PDF
38. Photoluminescence and structural properties of the nitrogen doped TiO2 and the influence of SiO2 and Ag nanoparticles
- Author
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Ion Smaranda, Adelina Udrescu, G. Mateescu, A.O. Mateescu, Constantin Catalin Negrila, Paul Mereuta, Mihaela Baibarac, and Andreea Nila
- Subjects
Range (particle radiation) ,Photoluminescence ,Materials science ,Band gap ,Analytical chemistry ,Electron ,Condensed Matter Physics ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Titanium dioxide ,symbols ,General Materials Science ,Photoluminescence excitation ,Spectroscopy ,Raman scattering - Abstract
Mixtures of nitrogen-doped titanium dioxide (TiO2:N) with different concentrations of Ag and/or SiO2 particles (0.5, 1 and 2 wt.%) were prepared in solid state by mechanico-chemical interactions. Using UV-VIS spectroscopy, Raman scattering, photoluminescence (PL) and photoluminescence excitation (PLE), the influence of the particles on the host material is evaluated. UV-VIS spectroscopy studies indicate a TiO2:N band gap shift to the UV range with increasing concentrations of SiO2 and Ag particles. PL intensities decrease with increasing concentrations of Ag and/or SiO2 particles in the TiO2:N host matrix, which in turn could effectively restrict the electron and hole recombination. To explain these processes, the different de-excitation ways will be advanced, taking into account the energy levels diagram of TiO2:N/Ag, TiO2:N/SiO2 and TiO2:N/Ag/SiO2 systems. PLE spectra show a gradual decrease in their relative intensities after 165 minute of continuous irradiation due to photosensitivity of TiO2:N. The plasmonic effect of Ag particles in the TiO2:N/Ag system is highlighted for the first time by PLE studies.
- Published
- 2019
- Full Text
- View/download PDF
39. Increased Diffusion Coefficient of Polymeric Nanocomposite Layer for Gas Sensing Applications
- Author
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Valentin S. Teodorescu, Cristian Viespe, Lucian Trupina, Constantin Catalin Negrila, Ionut Nicolae, and Natalia Serban
- Subjects
Nanocomposite ,Materials science ,Sensing applications ,Electrical and Electronic Engineering ,Composite material ,Diffusion (business) ,Layer (electronics) ,Atomic and Molecular Physics, and Optics - Published
- 2013
- Full Text
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40. Virtual Effort: An Advanced User Interface that Combines Various Visual Information with a Kinetic System for Virtual Object Manipulations
- Author
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Constantin Catalin Moldovan and Ionel Staretu
- Subjects
business.industry ,Computer science ,Perspective (graphical) ,Cognitive neuroscience of visual object recognition ,Motion detection ,General Medicine ,computer.software_genre ,Object detection ,Virtual image ,Virtual machine ,Computer vision ,Artificial intelligence ,User interface ,business ,computer - Abstract
The present day virtual environments are very advanced and have the ability to display complex representations of simulated objects together with their surroundings. Each virtual object can be endowed with multiple physical properties; in this way the entire virtual environment tends to become very real. However, human interaction with objects in virtual environments is forced from the user perspective and very different from how humans interact with objects in physical world. In this paper, a research that allows a more natural human-computer communication is presented. This is realized by combining visual information that is displayed to a user with kinetic information captured from the user hand by utilizing a sensor to capture depth data. The presented method is used in order to perform experiment that consist in grasping, moving and dropping a virtual object and analyze the hand trajectory compared with the virtual object trajectory.
- Published
- 2013
- Full Text
- View/download PDF
41. Software Modules for Command and Control of the Anthropomorphic Gripper for Robots
- Author
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Ionel Staretu, Alexandru Itu, and Constantin Catalin Moldovan
- Subjects
Engineering ,Engineering drawing ,business.industry ,Interface (computing) ,General Medicine ,Voice command device ,Tracing ,computer.software_genre ,Visualization ,Software ,Grippers ,Virtual machine ,Embedded system ,Robot ,business ,computer - Abstract
This paper presents two software modules of the general structure and implementation features of the original software for command and control of the anthropomorphic gripper for robots. The software has three modules: RoboVISION, RoboSIM and RoboCOMMANDER. RoboVISION is a software module for tracing, visualization, shape recognition, measurement, and efficiency evaluation for 3D model generation of objects to grip by an anthropomorphic gripper. It was presented in another paper. This paper discribes RoboSIM nad Robo COMMANDER. RoboSIM product is an advanced software module that aims primarily to reduce achievement time of functional simulation of anthropomorphic grippers. RoboCOMMANDER is a software module for controlling a three-fingered anthropomorphic robotic hand in both virtual and real environments. The approach is using a multimodal interface based on voice commands, remote manipulation, and smart, remote controlling mobile devices.
- Published
- 2013
- Full Text
- View/download PDF
42. Key-Policy Attribute-Based Encryption from Bilinear Maps
- Author
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Anca-Maria Nica, Constantin Catalin Dragan, and Ferucio Laurenţiu Ţiplea
- Subjects
Theoretical computer science ,Computer science ,business.industry ,Bilinear interpolation ,Data_CODINGANDINFORMATIONTHEORY ,0102 computer and information sciences ,Encryption ,01 natural sciences ,Secret sharing ,03 medical and health sciences ,0302 clinical medicine ,010201 computation theory & mathematics ,030220 oncology & carcinogenesis ,Attribute-based encryption ,business ,Key policy - Abstract
The aim of this paper is to provide an overview on the newest results regarding the design of key-policy attribute-based encryption (KP-ABE) schemes from secret sharing and bilinear maps.
- Published
- 2017
- Full Text
- View/download PDF
43. Temperature intelligent control based on soft computing technology
- Author
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Lucian Mastacan and Constantin-Catalin Dosoftei
- Subjects
Soft computing ,Engineering ,Temperature control ,business.industry ,Computer Science::Neural and Evolutionary Computation ,Fuzzy learning ,Control engineering ,02 engineering and technology ,Fuzzy logic controller ,Time response ,0202 electrical engineering, electronic engineering, information engineering ,Overshoot (signal) ,020201 artificial intelligence & image processing ,business ,Intelligent control ,Steady state error - Abstract
The paper presents an intelligent method based of soft computing to control thermal processes. A fuzzy logic controller (FLC) is designed to control the temperature of an electric oven. The temperature control is based on a fuzzy learning algorithm with auto-tuning capabilities in order to get as performances, time response as short as possible, small overshoot and zero steady state error. The auto-tuning FLC is implemented in LabVIEW software from National Instruments. The experimental results clearly emphasize the capabilities of the proposed FLC to realize the best performances.
- Published
- 2016
- Full Text
- View/download PDF
44. Software Module for a Virtual Anthropomorphic Gripper Preshaping
- Author
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Constantin Catalin Moldovan, Alexandru Itu, and Ionel Staretu
- Subjects
Engineering ,business.industry ,Interface (computing) ,Context (language use) ,Control engineering ,General Medicine ,Degrees of freedom (mechanics) ,Virtual reality ,computer.software_genre ,Set (abstract data type) ,Virtual machine ,Grippers ,Reduction (mathematics) ,business ,computer ,Simulation - Abstract
Virtual reality is an important technology in the context of product lifecycle management. Through virtual reality, one offers solutions in the design phase, but also during use, resulting in a significant reduction in time between concept and prototype stage and an overall process optimization increase. Control interfaces of anthropomorphic grippers in virtual environments allow carrying out a series of tests and simulations to validate both a particular design and the configuration of a certain gripping operation. The control interface of an anthropomorphic gripper is also responsible for the connection between the user and the virtual environment providing a set of tools for performing the functional simulation. This paper presents the RoboSIM software module, which is an advanced control interface for a three fingered anthropomorphic gripper. This module was primarily developed for easing the functional simulation of a three fingered gripper in a virtual environment. In order to further decrease the time between concept and prototype, RoboSIM was extended to directly communicate with the real gripper. In this way the functional simulations results can be directly transferred using RoboSIM to the real gripper which will perform the gripping operation accordingly. This novel approach is especially suited for anthropomorphic grippers which are known to have an increased number of degrees of freedom thus their control interfaces becoming very complex.
- Published
- 2012
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- View/download PDF
45. Real-Time Gesture Recognition for Controlling a Virtual Hand
- Author
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Ionel Staretu and Constantin Catalin Moldovan
- Subjects
business.industry ,Computer science ,General Engineering ,Cognitive neuroscience of visual object recognition ,Motion detection ,computer.software_genre ,Object detection ,Virtual machine ,Gesture recognition ,Video tracking ,Computer vision ,Artificial intelligence ,business ,computer ,Gesture - Abstract
Object tracking in three dimensional environments is an area of research that has attracted a lot of attention lately, for its potential regarding the interaction between man and machine. Hand gesture detection and recognition, in real time, from video stream, plays a significant role in the human-computer interaction and, on the current digital image processing applications, this represent a difficult task. This paper aims to present a new method for human hand control in virtual environments, by eliminating the need of an external device currently used for hand motion capture and digitization. A first step in this direction would be the detection of human hand, followed by the detection of gestures and their use to control a virtual hand in a virtual environment.
- Published
- 2012
- Full Text
- View/download PDF
46. Key-Policy Attribute-Based Encryption for General Boolean Circuits from Secret Sharing and Multi-linear Maps
- Author
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Ferucio Laurenţiu Ţiplea and Constantin Catalin Dragan
- Subjects
0301 basic medicine ,Homomorphic secret sharing ,business.industry ,Computer science ,Boolean circuit ,0102 computer and information sciences ,Encryption ,01 natural sciences ,Secret sharing ,03 medical and health sciences ,030104 developmental biology ,010201 computation theory & mathematics ,Probabilistic encryption ,Verifiable secret sharing ,Attribute-based encryption ,Arithmetic ,Bilinear map ,business ,Computer Science::Cryptography and Security - Abstract
We propose a Key-policy Attribute-based Encryption (KP-ABE) scheme for general Boolean circuits, based on secret sharing and on a very particular and simple form of leveled multi-linear maps, called chained multi-linear maps. The number of decryption key components is substantially reduced in comparison with the scheme in [7], and the size of the multi-linear map (in terms of bilinear map components) is less than the Boolean circuit depth, while it is quadratic in the Boolean circuit depth for the scheme in [7]. Moreover, the multiplication depth of the chained multi-linear map in our scheme can be significantly less than the multiplication depth of the leveled multi-linear map in the scheme in [7]. Selective security of the proposed scheme in the standard model is proved, under the decisional multi-linear Diffie-Hellman assumption.
- Published
- 2016
- Full Text
- View/download PDF
47. XPS Analysis of AuGeNi/Cleaved GaAs(110) Interface
- Author
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R. V. Ghita, Constantin-Catalin Negrila, Florica Frumosu, Lucian Trupina, M. F. Lazarescu, Constantin Logofatu, and Costel Cotirlan
- Subjects
Materials science ,Article Subject ,Alloy ,Ultra-high vacuum ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,01 natural sciences ,X-ray photoelectron spectroscopy ,Etching (microfabrication) ,0103 physical sciences ,lcsh:Technology (General) ,General Materials Science ,Ohmic contact ,010302 applied physics ,Argon ,business.industry ,021001 nanoscience & nanotechnology ,Semiconductor ,chemistry ,engineering ,lcsh:T1-995 ,0210 nano-technology ,business ,Layer (electronics) - Abstract
The depth composition of the thin layer alloy, AuGeNi, devoted to acting as an ohmic contact on n-GaAs(110) has been investigated by in situ XPS combined with Argon ion sputtering techniques. The fresh cleaved surfaces, supposed to be free of oxygen, were usually deposited with a 200 nm metallic layer in high vacuum conditions (better than 10−7 torr), by thermal evaporation, and annealed at a 430–450° Celsius temperature for 5 minutes. About 18 sessions of ion Ar surfaces etching and intermediate XPS measurements were performed in order to reveal the border of the metal/semiconductor interface. The atomic concentrations of the chemical elements have been approximated. Au4f, Ga3d, Ga2p, As3d, As2p, Ni2p3/2, Ge3d, O1s, and C1s spectral lines were recorded. The Au, Ge, and Ni have a homogenous distribution while Ga and As tend to diffuse to the surface. Oxygen is present in the first layers of the surface while carbon completely disappears after the second etching step. The existence of an Au-Ga alloy was detected and XPS spectra show only metal Ni and Ge within the layer and at the interface. We tried to perform a study about the depth chemical composition profile analysis of AuGeNi layer on cleaved n-GaAs(110) by X-Ray Photoelectron Spectroscopy (XPS) technique.
- Published
- 2016
48. Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure
- Author
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Adrian-Claudiu Popa, Constantin-Catalin Negrila, Łukasz Kołodziejczyk, R G Ripeanu, Alina Vladescu, Cristina Besleaga, Gabriela-Cristina Ionescu, L. M. Trinca, George E. Stan, Catalin-Romeo Luculescu, and Viorel Georgel Dumitru
- Subjects
Nanostructure ,Materials science ,General Chemical Engineering ,Nanotechnology ,02 engineering and technology ,Substrate (electronics) ,Nitride ,01 natural sciences ,Article ,Corrosion ,lcsh:Chemistry ,biocompatibility ,0103 physical sciences ,General Materials Science ,structure ,Thin film ,010302 applied physics ,corrosion ,magnetron sputtering ,Delamination ,aluminum nitride ,nano-mechanical tests ,Sputter deposition ,021001 nanoscience & nanotechnology ,lcsh:QD1-999 ,Cavity magnetron ,0210 nano-technology - Abstract
Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for its intrinsic piezoelectricity, its surface morphology and mechanical performance (elastic modulus, hardness, wear, scratch and tensile resistance to delamination, adherence to the substrate), corrosion resistance and cytocompatibility are also essential features for high performance sustainable biosensor devices. However, information about AlN suitability for such applications is rather scarce or at best scattered and incomplete. Here, we aim to deliver a comprehensive evaluation of the morpho-structural, compositional, mechanical, electrochemical and biological properties of reactive radio-frequency magnetron sputtered AlN nanostructured thin films with various degrees of c-axis texturing, deposited at a low temperature (~50 °C) on Si (100) substrates. The inter-conditionality elicited between the base pressure level attained in the reactor chamber and crystalline quality of AlN films is highlighted. The potential suitability of nanostructured AlN (in form of thin films) for the realization of various type of sensors (with emphasis on bio-sensors) is thoroughly probed, thus unveiling its advantages and limitations, as well as suggesting paths to safely exploit the remarkable prospects of this type of materials.
- Published
- 2017
- Full Text
- View/download PDF
49. Level Fuzzy Control of Three-Tank System
- Author
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Constantin-Catalin Dosoftei and Lucian Mastacan
- Subjects
Fuzzy classification ,Fuzzy rule ,Mathematics::General Mathematics ,Computer science ,Fuzzy control system ,Type-2 fuzzy sets and systems ,computer.software_genre ,Defuzzification ,Fuzzy mathematics ,Fuzzy set operations ,Fuzzy number ,ComputingMethodologies_GENERAL ,Data mining ,computer - Abstract
Look-up decisions tables are favorites in fuzzy control when a complex algorithm of fuzzy rules inference is an impediment for a real time application. The control values of look-up tables are fuzzy singletons in finite number. It is difficult to obtain the best fuzzy control performance in these conditions. The look-up tables can be assimilated to sparse fuzzy rule bases. A linear interpolation method applied in a look-up decision table increase to a large number the fuzzy control values. In this way the fuzzy control performance can be improved. A level fuzzy control of three-tank system is implemented to validate the proposed method.
- Published
- 2013
- Full Text
- View/download PDF
50. Neuro-Fuzzy Models of Thermoelectric Power Station Installations
- Author
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Constantin-Catalin Dosoftei, Lucian Mastacan, Iosif Olah, and D. Ivana
- Subjects
Soft computing ,Reduction (complexity) ,Energy conservation ,Neuro-fuzzy ,Power station ,Computer science ,Fuel efficiency ,Electrical efficiency ,Reliability engineering ,Power (physics) - Abstract
Taking into account the technical and economical problems with which the combined heat and power plants are confronted, after the reorganization of this domain in Romania, in order to improve the normal operation with small-efficiency when these centralized units are maintained in function, the paper proposes the implementation of a modeling method based on the soft computing theory. The main objective of the research team is in connection with the improvement of the performance and competitive of a combined heat and power plant total activity, through the fuel consumption reduction, the power efficiency increase and guaranteeing the supply with energy services by means of measures relating to the offer and demand, the power and heat production cost reduction. With that end in view the scientific research is focused on the theoretical and practical implementation of new hybrid neuro-fuzzy method to model the technological processes from a combined heat and power plant
- Published
- 2006
- Full Text
- View/download PDF
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