26 research outputs found
Cohomology of Hom-Lie superalgebras and q-deformed Witt superalgebra
The purpose of this paper is to define the representation and the cohomology
of Hom-Lie superalgebras. Moreover we study Central extensions and provide as
application the computations of the derivations and second cohomology group of
q-deformed Witt superalgebra
Robust fault detection by simultaneous observers
Ankara : The Department of Electrical and Electronics Engineering and The Institute of Engineering and Science of Bilkent Univ., 2000.Thesis (Master's) -- Bilkent University, 2000.Includes bibliographical references leaves 63-68This thesis addresses the problem of fault detection and isolation in linear
systems based on unknown input observers.
Functional disturbance decoupled observers which estimate specified or unspecified
linear functions of system states regardless of the disturbances are first
studied. Necessary and sufficient condition for the existence of such observers
are presented. The investigation is extended to simultaneous disturbance decoupled
observers where multiple systems are observed by a single disturbance
decoupled observer.
The application of disturbance decoupled observers to fault detection and
diagnosis are explicitly outlined, and a new scheme that is based on simultaneous
unknown input observers is proposed to enhance the already existing
schemes.
Finally, a detailed simulation example is carried out to examine the utility
of the proposed scheme.Ammar, NejibM.S
An Overview of the ATSC 3.0 Physical Layer Specification
"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")This paper provides an overview of the physical layer specification of Advanced Television Systems Committee (ATSC) 3.0, the next-generation digital terrestrial broadcasting standard. ATSC 3.0 does not have any backwards-compatibility constraint with existing ATSC standards, and it uses orthogonal frequency division multiplexing-based waveforms along with powerful low-density parity check (LDPC) forward error correction codes similar to existing state-of-the-art. However, it introduces many new technological features such as 2-D non-uniform constellations, improved and ultra-robust LDPC codes, power-based layered division multiplexing to efficiently provide mobile and fixed services in the same radio frequency (RF) channel, as well as a novel frequency pre-distortion multiple-input single-output antenna scheme. ATSC 3.0 also allows bonding of two RF channels to increase the service peak data rate and to exploit inter-RF channel frequency diversity, and to employ dual-polarized multiple-input multiple-output antenna system. Furthermore, ATSC 3.0 provides great flexibility in terms of configuration parameters (e.g., 12 coding rates, 6 modulation orders, 16 pilot patterns, 12 guard intervals, and 2 time interleavers), and also a very flexible data multiplexing scheme using time, frequency, and power dimensions. As a consequence, ATSC 3.0 not only improves the spectral efficiency and robustness well beyond the first generation ATSC broadcast television standard, but also it is positioned to become the reference terrestrial broadcasting technology worldwide due to its unprecedented performance and flexibility. Another key aspect of ATSC 3.0 is its extensible signaling, which will allow including new technologies in the future without disrupting ATSC 3.0 services. This paper provides an overview of the physical layer technologies of ATSC 3.0, covering the ATSC A/321 standard that describes the so-called bootstrap, which is the universal entry point to an ATSC 3.0 signal, and the ATSC A/322 standard that describes the physical layer downlink signals after the bootstrap. A summary comparison between ATSC 3.0 and DVB-T2 is also provided.Fay, L.; Michael, L.; GĂłmez Barquero, D.; Ammar, N.; Caldwell, MW. (2016). An Overview of the ATSC 3.0 Physical Layer Specification. IEEE Transactions on Broadcasting. 62(1):159-171. doi:10.1109/TBC.2015.2505417S15917162
Investigating Robustness in Cyber-Physical Systems: Specification-Centric Analysis in the face of System Deviations
The adoption of cyber-physical systems (CPS) is on the rise in complex
physical environments, encompassing domains such as autonomous vehicles, the
Internet of Things (IoT), and smart cities. A critical attribute of CPS is
robustness, denoting its capacity to operate safely despite potential
disruptions and uncertainties in the operating environment. This paper proposes
a novel specification-based robustness, which characterizes the effectiveness
of a controller in meeting a specified system requirement, articulated through
Signal Temporal Logic (STL) while accounting for possible deviations in the
system. This paper also proposes the robustness falsification problem based on
the definition, which involves identifying minor deviations capable of
violating the specified requirement. We present an innovative two-layer
simulation-based analysis framework designed to identify subtle robustness
violations. To assess our methodology, we devise a series of benchmark problems
wherein system parameters can be adjusted to emulate various forms of
uncertainties and disturbances. Initial evaluations indicate that our
falsification approach proficiently identifies robustness violations, providing
valuable insights for comparing robustness between conventional and
reinforcement learning (RL)-based controllersComment: 12 page
Entropy Generation Analysis of a Chemical Absorption Process Where Carbon Dioxide is Absorbed by Falling Monoethanolamine Solution Film
The present paper reports a study about entropy generation analysis for the case of chemical absorption of a gas into laminar falling liquid film. The CO 2 absorption into monoethanolamine (MEA) aqueous solutions has been considered. Temperature and concentration expressions are determined by using Laplace transform and used for the entropy generation calculation. The effects of irreversibilities due to heat transfer, mass transfer, viscous effects, coupling effects between heat and mass transfer, and chemical reaction on the total entropy generation of the considered system are derived. The obtained results show that entropy generation is mainly due to chemical reaction irreversibility at the gas-liquid interface. Between this interface and the reaction film thickness (where the reaction take place), entropy generation is due to both chemical reaction and mass transfer irreversibilities. More details concerning the contribution of each kind of irreversibility to entropy generation through the falling film are graphically presented and discussed
Global Lipschitz stability of multiple space dependent ionic parameters for the MEA/hiPSC-CM assays
International audienceAbstract In this paper, we consider an inverse problem of determining two space dependent ionic parameters of a strongly coupled parabolic-elliptic reaction–diffusion system arising in cardiac electrophysiology modeling when simulating drugs action with multi-electrode array/human induced pluripotent stem cells-cardiomyocytes assays. We use the bidomain model coupled to an ordinary differential equation and we consider the classical phenomenological model in cardiac electrophysiology of FitzHugh–Nagumo to describe the ionic exchanges at the microscopic level. Our main result is the uniqueness and a Lipschitz stability estimate for two ionic parameters ( k , γ ) of the model using sub-boundary observations over an interval of time. The key ingredients are a global Carleman-type estimates with a suitable observations acting on a part of the boundary
Second Law Analysis of a Gas-Liquid Absorption Film
This paper reports an analytical study of the second law in the case of gas absorption into a laminar falling viscous incompressible liquid film. Velocity, temperature, and concentration profiles are determined and used for the entropy generation calculation. Irreversibilities due to heat transfer, fluid friction, and coupling effects between heat and mass transfer are derived. The obtained results show that entropy generation is mainly due to coupling effects between heat and mass transfer near the gas-liquid interface. Total irreversibility is minimum at the diffusion film thickness. On approaching the liquid film thickness, entropy generation is mainly due to viscous irreversibility