Relevant bibliographies by topics / Non-stationary dynamic processes

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Non-stationary dynamic processes'

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Published: 28 May 2022

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Journal articles on the topic "Non-stationary dynamic processes"

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Resnick, Sidney, and Rishin Roy. "Multivariate extremal processes, leader processes and dynamic choice models." Advances in Applied Probability 22, no. 02 (June 1990): 309–31. http://dx.doi.org/10.1017/s0001867800019595.

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Let ( Y (t), t > 0) be a d-dimensional non-homogeneous multivariate extremal process. We suppose the ith component of Y describes time-dependent behaviour of random utilities associated with the ith choice. At time t we choose the ith alternative if the ith component of Y (t) is the largest of all the components. Let J(t) be the index of the largest component at time t so J has range {1, …, d} and call {J(t)} the leader process. Let Z(t) be the value of the largest component at time t. Then the bivariate process (J(t), Z(t)} is Markov. We discuss when J(t) and Z(t) are independent, when {J(s), 0<s≦t} and Z(t) are independent and when J(t) and {Z(s), 0<s≦t} are independent. In usual circumstances, {J(t)} is Markov and particular properties are given when the underlying distribution is max-stable. In the max-stable time-homogeneous case, {J(et )} is a stationary Markov chain with stationary transition probabilities.
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Resnick, Sidney, and Rishin Roy. "Multivariate extremal processes, leader processes and dynamic choice models." Advances in Applied Probability 22, no. 2 (June 1990): 309–31. http://dx.doi.org/10.2307/1427538.

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Let (Y(t), t > 0) be a d-dimensional non-homogeneous multivariate extremal process. We suppose the ith component of Y describes time-dependent behaviour of random utilities associated with the ith choice. At time t we choose the ith alternative if the ith component of Y(t) is the largest of all the components. Let J(t) be the index of the largest component at time t so J has range {1, …, d} and call {J(t)} the leader process. Let Z(t) be the value of the largest component at time t. Then the bivariate process (J(t), Z(t)} is Markov. We discuss when J(t) and Z(t) are independent, when {J(s), 0<s≦t} and Z(t) are independent and when J(t) and {Z(s), 0<s≦t} are independent. In usual circumstances, {J(t)} is Markov and particular properties are given when the underlying distribution is max-stable. In the max-stable time-homogeneous case, {J(et)} is a stationary Markov chain with stationary transition probabilities.
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Hartert, L., M. Sayed Mouchaweh, and P. Billaudel. "Dynamic Fuzzy Pattern Matching for the monitoring of non stationary processes." IFAC Proceedings Volumes 42, no. 8 (2009): 516–21. http://dx.doi.org/10.3182/20090630-4-es-2003.00086.

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Grzegorczyk, Marco, Dirk Husmeier, and Jörg Rahnenführer. "Modelling non-stationary dynamic gene regulatory processes with the BGM model." Computational Statistics 26, no. 2 (June 15, 2010): 199–218. http://dx.doi.org/10.1007/s00180-010-0201-9.

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Grishin, Y. A., and V. N. Bakulin. "Application of non-stationary gas dynamic functions for mathematical modeling of gas dynamic processes." Journal of Physics: Conference Series 1392 (November 2019): 012038. http://dx.doi.org/10.1088/1742-6596/1392/1/012038.

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Solecki, William, and Cynthia Rosenzweig. "Climate Change, Extreme Events, and Hurricane Sandy: From Non-Stationary Climate to Non-Stationary Policy." Journal of Extreme Events 01, no. 01 (August 2014): 1450008. http://dx.doi.org/10.1142/s2345737614500080.

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This paper illustrates and examines the development of a flexible climate adaptation approach and non-stationary climate policy in New York City in the post-Hurricane Sandy context. Extreme events, such as Hurricane Sandy, are presented as learning opportunities and create a policy window for outside-of-the-box solutions and experimentation. The research investigates the institutionalization of laws, standards, and codes that are required to reflect an increasingly dynamic set of local environmental stresses associated with climate change. The City of New York responded to Hurricane Sandy with a set of targeted adjustments to the existing infrastructure and building stock in a way that both makes it more resistant (i.e., strengthened) and resilient (i.e., responsive to stress) in the face of future extreme events. Post-Sandy New York experiences show that the conditions for a post-disaster flexible adaptation response exist, and evidence shows that the beginnings of a non-stationary policy generation process have been put into place. More broadly, post-disaster policy processes have been configured in New York to enable continuous co-production of knowledge by scientists and the community of decision-makers and stakeholders.
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Bod’ová, Katarína, Enikő Szép, and Nicholas H. Barton. "Dynamic maximum entropy provides accurate approximation of structured population dynamics." PLOS Computational Biology 17, no. 12 (December 1, 2021): e1009661. http://dx.doi.org/10.1371/journal.pcbi.1009661.

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Realistic models of biological processes typically involve interacting components on multiple scales, driven by changing environment and inherent stochasticity. Such models are often analytically and numerically intractable. We revisit a dynamic maximum entropy method that combines a static maximum entropy with a quasi-stationary approximation. This allows us to reduce stochastic non-equilibrium dynamics expressed by the Fokker-Planck equation to a simpler low-dimensional deterministic dynamics, without the need to track microscopic details. Although the method has been previously applied to a few (rather complicated) applications in population genetics, our main goal here is to explain and to better understand how the method works. We demonstrate the usefulness of the method for two widely studied stochastic problems, highlighting its accuracy in capturing important macroscopic quantities even in rapidly changing non-stationary conditions. For the Ornstein-Uhlenbeck process, the method recovers the exact dynamics whilst for a stochastic island model with migration from other habitats, the approximation retains high macroscopic accuracy under a wide range of scenarios in a dynamic environment.
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Kubarev, Yu V., V. A. Kotelnikov, and M. V. Kotelnikov. "Probe Diagnostics of Physical Processes in Magneto-Dynamic Plasma." Proceedings of Universities. Electronics 26, no. 2 (April 2021): 132–43. http://dx.doi.org/10.24151/1561-5405-2021-26-2-132-143.

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Plasma streams flowing from space engines interact with other life-support systems of space stations, in particular with solar panels. The magneto-plasmadynamic motor is a source of rarefied low-temperature plasma and can be used in production of semiconductor devices, integrated circuits and in a number of other areas. At the same time, the optimization of such a plasma source involves the active use of electric probes for diagnosis of plasma formations. In the work the original methods for processing the probe experiments in plasma flows, including the use of flat and cylindrical oriented probes as well as the non-stationary probes, which allows expanding the capabilities of the probe method for plasma diagnostics, have been presented. The optimization of the probe measurement schemes has been discussed. The results of probe mea-surements in jets, both in the bench conditions and in conditions of the Earth’ ionosphere, have been presented. The study has been carried out using both full-scale and computational experi-ments. In the work the original methods for processing the probe experiments in plasma flows, including the use of flat and cylindrical oriented probes, as well as non-stationary probes, which allows expanding the capabilities of the probe method of plasma diagnostics, have been pre-sented. The studies have been carried out using the bench and computational schemes. The re-sults obtained are important for plasmadynamic technologies in microelectronics and for radio communication with spacecraft powered by plasmadynamic engines.
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Panek, Emil. "“Strong” Turnpike Effect in the Non-Stationary Gale Economy with Limit Technology." Przegląd Statystyczny 63, no. 2 (June 30, 2016): 109–22. http://dx.doi.org/10.5604/01.3001.0014.1155.

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This article, in reference to Panek (2013a) presents proof of the “strong” turnpike theorem in the non-stationary Gale economy with changeable technology convergent to some limit technology. In the proof of the theorem assumption, that production processes efficiency in the economy is the lower the more the investment/input structure in such processes differs the optimum, play significant roles.The paper is part of trend of few works of mathematical economics containing proofs of the turnpike theorems in the non-stationary dynamic Neumann-Gale economic models.
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APETAUR, Milan, and František OPIČKA. "Small Vibrations of Nonlinear Dynamic Systems Containing Non-Rigid Bodies Excited by Stationary Stochastic Processes." Vehicle System Dynamics 20, no. 1 (January 1991): 3–19. http://dx.doi.org/10.1080/00423119108968977.

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Dissertations / Theses on the topic "Non-stationary dynamic processes"

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Li, Laihang. "Transient Vibration Amplification in Nonlinear Torsional Systems with Application to Vehicle Powertrain." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385369839.

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Teles, Tarcisio Nunes. "Mecânica estatística em sistemas com interações de longo alcance : estados estacionários e equilíbrio." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/55450.

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Desde os trabalhos de Clausius, Boltzmann e Gibbs, sabe-se que partículas que interagem através de potenciais de curto alcance alcançam, após um processo de relaxação, o estado final estacionário que corresponde ao equilíbrio termodinâmico [I]. Embora nenhuma prova exata exista para isso, na prática, verifica-se que os sistemas não-integráveis com uma energia fixa e um número finito de partículas (ensemble microcanônico, por exemplo) sempre relaxam para um estado estacionário que só depende de quantidades globais conservadas pela dinâmica: energia, momentum e momentum angular. Este estado estacionário corresponde ao estado de equilíbrio termodinâmico e não depende das especificidades da distribuição inicial de partículas. Este cenário muda drasticamente quando a interação entre as partículas passa a ser de longo alcance [2]. A descrição estatística e termodinâmica desses sistemas ainda é objeto de estudo. Contudo, o que se sabe é que esses sistemas têm como propriedade fundamental o fato de que, no limite termodinâmico o tempo de colisão diverge e o equilíbrio termodinâmico nunca é atingido [3]. Nesse trabalho analisamos do ponto de vista teórico e por simulação de dinâmica molecular o estado estacionário atingido por sistemas auto-gravitantes em uma, duas e três dimensões e plasmas não-neutros na dinâmica de um feixe de partículas carregadas. Analisamos ainda um modelo com transição de fases para o estado fora do equilíbrio (HMF). Em todos os casos a teoria proposta na tese mostrou-se consistente com os simulações numéricas empregadas.
Since the work of Clausius, Boltzmann and Gibbs, it is known that particles interacting by a short-range potential, after a relaxation process, reach a final stationary state that corresponds to thermodynamic equilibrium. Although no exact proof exists, in practice non-integrable systems with fixed energy and a finite number of particles (i.e., microcanonical ensemble) always relax to a stationary state that depends only on global quantities conserved by the dynamics: energy, momentum and angular momentum. This stationary state corresponds to the state of thermodynamic equilibrium and does not depend on the specifics of the initial particle distribution. This scenario changes drastically when the interaction between particles is longranged [2] The statistical and thermodynamic description of these systems is still an object of study. However, a fundamental property of these systems is the fact that, in the thermodynamic limit, the collision time diverges and thermodynamic equilibrium is never achieved [3].. In this thesis we analyse, from a theoretical point of view and using molecular dynamics simulations, the stationary state achieved by self-gravitating systems in one, two and three dimensions and non-neutral plasmas in the dynamics of charged particle beams. We also analyse a model with out-of-equilibrium phase transitions (HMF). In all these cases, the theory proposed in this thesis is shown to be consistent with the numerical simulations applied.
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Moya, Hiram. "Border Crossing Modeling and Analysis: A Non-Stationary Dynamic Reallocation Methodology For Terminating Queueing Systems." Thesis, 2012. http://hdl.handle.net/1969.1/ETD-TAMU-2012-08-11772.

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The United States international land boundary is a volatile, security intense area. In 2010, the combined trade was $918 billion within North American nations, with 80% transported by commercial trucks. Over 50 million commercial vehicles cross the Texas/Mexico border every year, not including private vehicles and pedestrian traffic, between Brownsville and El Paso, Texas, through one of over 25 major border crossings called "ports of entry" (POE). Recently, securing our southwest border from terrorist interventions, undocumented immigrants, and the illegal flow of drugs and guns has dominated the need to efficiently and effectively process people, goods and traffic. Increasing security and inspection requirements are seriously affecting transit times. Each POE is configured as a multi-commodity, prioritized queueing network which rarely, if ever, operates in steady-state. Therefore, the problem is about finding a balance between a reduction of wait time and its variance, POE operation costs, and the sustainment of a security level. The contribution of the dissertation is three-fold. The first uses queueing theory on the border crossing process to develop a methodology that decreases border wait times without increasing costs or affecting security procedures. The outcome is the development of the Dynamic Reallocation Methodology (DRM). Currently at the POE, inspection stations are fixed and can only inspect one truck type, FAST or Non-FAST program participant. The methodology proposes moveable servers that once a threshold is met, can be switched to service the other type of truck. Particular emphasis is given to inspection (service) times under time-varying arrivals (demands). The second contribution is an analytical model of the POE, to analyze the effects of the DRM. First assuming a Markovian service time, DRM benefits are evaluated. However, field data and other research suggest a general distribution for service time. Therefore, a Coxian k-phased approximation is implemented. The DRM is analyzed under this new baseline using expected number in the system, and cycle times. A variance reduction procedure is also proposed and evaluated under DRM. Results show that queue length and wait time is reduced 10 to 33% depending on load, while increasing FAST wait time by less than three minutes.
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Book chapters on the topic "Non-stationary dynamic processes"

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Hourbracq, Matthieu, Pierre-Henri Wuillemin, Christophe Gonzales, and Philippe Baumard. "Real Time Learning of Non-stationary Processes with Dynamic Bayesian Networks." In Information Processing and Management of Uncertainty in Knowledge-Based Systems, 338–50. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-40596-4_29.

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Dubrouski, Vasil, Anatolii Semenko, Mykola Kushnir, and Mohammed M. Steita. "Parametric Analysis of Statistical and Correlation Characteristics of Discrete Processes in Dynamic Systems with Non-stationary Nonlinearities in Time for the Secure Intent-Based Networks." In Lecture Notes in Electrical Engineering, 242–56. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-92435-5_14.

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Rottmann, Axel, and Wolfram Burgard. "Learning Non-stationary System Dynamics Online Using Gaussian Processes." In Lecture Notes in Computer Science, 192–201. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-15986-2_20.

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Meish, Vladimyr, and Yuliia Meish. "THE WAVE PROCESSES IN THREE-LAYER SHELLS OF ROTATIONWITH TAKING INTO ACCOUNT THE DISCRETE FILLER AT NON-STATIONARY LOADS." In Integration of traditional and innovation processes of development of modern science. Publishing House “Baltija Publishing”, 2020. http://dx.doi.org/10.30525/978-9934-26-021-6-36.

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Thin-walled shell structures in the form of plates and shells of various shapes have a high bearing capacity, lightness, and relative ease of manufacture. Three-layer shell elements, which consist of two bearing layers and a filler, which ensures their joint work, are widely used in mechanical engineering, industrial and civil construction, aviation and space technology, shipbuilding. When calculating the strength of three-layer shell structures with a discrete filler under dynamic loads, it becomes necessary to determine the stress-strain state both in the area of a sharp change in the geometry of the structure and at a considerable distance from the heterogeneity. The complexity of the processes that arise in this case necessitates the use of modern numerical methods for solving dynamic problems of the behavior of three-layer shell elements with a discrete filler. In this regard, the determination of the stress-strain state of three-layer shells with a discrete filler under non-stationary loads and the development of an effective numerical method for solving problems of this class is an urgent problem in the mechanics of a deformable solid. On the basis of the theory of threelayered shells with applying the hypotheses for each layer the nonstationary vibrations threelayered shells of revolution with allowance of discrete fillers are investigated. Hamilton-Ostrogradskyy variational principle for dynamical processes is used for deduction of the motion equations. An efficient numerical method for solution of problems on nonstationary behaviour of threelayers shells of revolution with allowance of discrete fillers are used. The wide diapason of geometrical, and physico-mechanical parameters of nonhomohenes threelayered structure are considerated. On the basis of the offered model nonstationary problems of the forced nonlinear vibrations of threelayered shells of revolution of various structure are solved and analysed. The basis of the developed numerical method for the study of nonstationary oscillations is the application of explicit finite-difference schemes to solve the initial differential equations in partial derivatives. The theory is based on the relations of the theory of three-layer shells of revolution taking into account the discreteness of the filler, which are based on the hypotheses of the geometrically nonlinear theory of shells and rods of the Timoshenko type.
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Dorça, Fabiano Azevedo. "Evolutionary Approach for Automatic and Dynamic Modeling of Students' Learning Styles." In Artificial Intelligence Applications in Distance Education, 261–84. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-6276-6.ch015.

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Most of the distance educational systems consider only little, or no, adaptivity. Personalization according to specific requirements of an individual student is one of the most important features in adaptive educational systems. Considering learning and how to improve a student's performance, these systems must know the way in which an individual student learns best. In this context, this chapter depicts an application of evolutionary algorithms to discover students' learning styles. The approach is mainly based on the non-deterministic and non-stationary aspects of learning styles, which may change during the learning process in an unexpected and unpredictable way. Because of the stochastic and dynamic aspects enclosed in learning process, it is important to gradually and constantly update the student model. In this way, the student model stochastically evolves towards the real student's learning style, considering its fine-tuned strengths. This approach has been tested through computer simulation of students, and promising results have been obtained. Some of them are presented in this chapter.
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Conference papers on the topic "Non-stationary dynamic processes"

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Khalil, Mohamed, Roland Wüchner, and Kai-Uwe Bletzinger. "Generalization of Spectral Methods for High-Cycle Fatigue Analysis to Accommodate Non-Stationary Random Processes." In ASME 2019 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/dscc2019-9074.

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Abstract Estimation of material fatigue life is an essential task in many engineering fields. When non-proportional loads are applied, the methodology to estimate fatigue life grows in complexity. Many methods have been proposed to solve this problem both in time and frequency domains. The former tends to give more accurate results, while the latter seems to be more computationally favorable. Until now, the focus of frequency-based methods has been limited to signals assumed to follow a stationary statistic process. This work proposes a generalization to the existing methods to accommodate non-stationary processes as well. A sensitivity analysis is conducted on the influence of the formulation’s hyper-parameters, followed by a numerical investigation on different signals and various materials to assert the robustness of the method.
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Lortz, Wolfgang, and Radu Pavel. "Fundamentals in Metal Plasticity: From the Initial Contact to Non-Stationary, Dynamic Chip." In ASME 2020 15th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/msec2020-8369.

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Abstract The process mechanics phenomena play an important role in all metal cutting processes. Conditions are changing progressively not only to high velocities and deformation, but also to the interfacial friction between two different materials — tool and workpiece, and inside the same material, as a result of material flow with high temperatures. It will be shown, that during the ploughing effect in the interface between tool and chips there are two different kinds of friction, external and internal friction. All the existent models ignore this reality. Therefore, an alternative must be found to model the real phenomena during metal plastic flow in a more appropriate manner. In this study, we will consider the cutting process in fundamental terms based only on mathematics and physics. In connection with this fundamental development a question arises, “Which parameters are the best for characterizing the cutting process and can the equations be proven after processing, because nearly each parameter will disappear, such as stress, strain, friction or temperatures etc.”? It might be that only the plastic material deformation in connection with the external and internal friction can be identified and visualized after the cutting process for comparing the developed theoretical result with the experimental result of the chip formation region. That leads to the fact that, as long as agreement between theoretical and experimental result can be demonstrated, there is evidence that stress and strain, as well as friction and temperatures are correctly estimated. Therefore, this paper is focused on the plastic deformation ds in the plastic region during the cutting process. This plastic deformation will be expressed for the non-stationary, dynamic cutting process with non-uniform feed (toolworkpiece contact evolving from rubbing to material separation) and chip flow. This process behavior is relevant for the milling operation of metals as well as for carbon composites with glass fibers. For carbon composites with glass fibers, additional environmental and human safety aspects will arise, as described in this paper.
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Lua, James, and E. Thomas Mover. "First-Excursion Probability and Response Peak Distribution of a Nonlinear Structure Under Non-Gaussian Non-Stationary Loadings." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0392.

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Abstract Probabilistic methods have been used recently for the reliability assessment and design of ship structures because of the presence of various uncertainties in structural configuration, material properties, and environmental and operating conditions. Among these uncertainties, random dynamic loads induced by either sea waves or slamming play a significant role in reliability-based ship structural design. The present state-of-the-art probabilistic method for ship design is based on a linear structural response model subjected to stationary Gaussian random processes. However, under extreme operating conditions, the ship structural response may not be linear due to the initiation and evolution of multiple local damage, such as local plastic deformation, stiffener tripping, panel buckling, or fracture. In addition, the complexity of fluid-structure interaction phenomena may render the assumptions on the loading process (stationary and Gaussian) invalid. Under this study, we developed a simulation based probabilistic analysis framework for a nonlinear dynamic structural system under non-Gaussian non-stationary loadings. The general simulation based probabilistic analysis framework (SIMLAB) is formulated by integrating 1) random variable generating modules; 2) random process generation modules; and 3) user selected deterministic solver and limit state function. The developed random process simulation module is able to generate a Gaussian, non-Gaussian, stationary, or non-stationary process. To demonstrate the applicability of the developed tool for a structural dynamic system with random variables and random processes, a free-free beam subjected to a sea wave induced random process is solved by integrating a structural dynamics code, DYNA3D, with the developed probabilistic analysis framework. The limit state function is formulated based on the first crossing of a beam Von Mises stress at an integration point above a safe threshold. In order to validate the accuracy of SIMLAB, a linear beam structure subjected to a stationary Gaussian process is considered first and the simulated statistical distributions of peak and extreme response variables are compared with analytical predictions. The effect of material nonlinearity on probability of failure and peak statistics is explored by using an elastoplastic beam model subjected to a random excitation. Results on probability of failure and peak statistics are compared with the corresponding statistical models for a linear structure. The great versatility of the simulation based probabilistic analysis framework provides us a solid foundation for the development of more advanced probabilistic analysis tools for reliability-based ship design.
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Marano, Giuseppe Carlo, Giuseppe Acciani, and Angelamaria Abrescia. "Numerical Algorithm for Non-Stationary Covariance Analysis of Nonlinear Mechanical System Using Equivalent Stochastic Linearization." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20448.

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A quite important topic of structural dynamics is deterministic mechanical systems subjected to stochastic dynamic actions, such as for wind or earthquake. IN such cases structural response have to be properly evaluated by a stochastic approach. Unfortunately for nonlinear mechanical systems only in a very few cases exact solutions are available, and usually simply approximate solutions should be used. A well known one is stochastic equivalent linearization, easy and simple from the conceptual point of view. Moreover it needs of specific numerical techniques to be properly implemented, whose complexity increases in case of non stationary conditions. In this paper a procedure to solve covariance analysis of stochastic linearized systems in case of non stationary excitation is proposed. The no stationary Lyapunov differential matrix covariance equation for the linearized system is solved by using a numerical algorithm that updates linearized system matrix coefficients step by step. This by a predictor-corrector procedure applied to a Euler-implicit integration scheme for the matrix covariance analysis. It is described in details to be simpler implemented by other researchers, and then applied to a typical and important applicative case, that is seismic response of a Bouc Wen Single Degree of Freedom (SDoF) system. Seismic input processes is modeled as linear filtered white noise non stationary separable process. Accuracy and computational costs are analyzed showing the efficiency of the proposed integrating procedure.
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Jeong, Jinho, Soo Jeon, and Jongeun Choi. "Learning Hyperparameters in Efficient Spatial Model by Robotic Sensors." In ASME 2019 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/dscc2019-9170.

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Abstract Recently, a new class of spatial models over a continuum domain that builds on hidden Gaussian Markov Random Fields (GMRFs) was proposed for resource-constrained networked mobile robots dealing with non-stationary physical processes. The hidden GMRF was realized with respect to a proximity graph over a surveillance region. In this paper, we investigate learning strategies based on the maximum likelihood (ML) and the maximum a posteriori (MAP) estimators to find the locational generating points for the spatial model so that mobile robots can efficiently make the prediction. Some promising simulation results and future research directions are discussed.
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Xu, Yunfei, and Jongeun Choi. "Spatial Prediction With Mobile Sensor Networks Using Gaussian Process Regression Based on Gaussian Markov Random Fields." In ASME 2011 Dynamic Systems and Control Conference and Bath/ASME Symposium on Fluid Power and Motion Control. ASMEDC, 2011. http://dx.doi.org/10.1115/dscc2011-6092.

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In this paper, a new class of Gaussian processes is proposed for resource-constrained mobile sensor networks. Such a Gaussian process builds on a GMRF with respect to a proximity graph over a surveillance region. The main advantages of using this class of Gaussian processes over standard Gaussian processes defined by mean and covariance functions are its numerical efficiency and scalability due to its built-in GMRF and its capability of representing a wide range of non-stationary physical processes. The formulas for Bayesian posterior predictive statistics such as prediction mean and variance are derived and a sequential field prediction algorithm is provided for sequentially sampled observations. For a special case using compactly supported kernels, we propose a distributed algorithm to implement field prediction by correctly fusing all observations in Bayesian statistics. Simulation results illustrate the effectiveness of our approach.
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Kim, SooYong, Valeri P. Kovalevski, and V. Goldenberg. "Numerical Study of Heat and Aerodynamic Processes in Regenerators of an Inert Gas Generator (IGG)." In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68230.

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The cooling scheme for inert gas exhausting from a small gas turbine engine is presented and its performance, including the gas injector and regenerator, are investigated. A distributed, nonlinear mathematical model used to study the processes in regenerative heat exchangers is also described. An integral scheme of a conjugated problem of a non-stationary heat exchange of both one-dimensional streams and a two-dimensional matrix wall are presented. Comparison of test calculations made using the developed program with experimental data of different authors has shown satisfactory agreement. The extensive study results of quasistationary, dynamic heat and aerodynamic processes in regenerators with four types of matrices are introduced: ceramic matrix with straight rectangular cross-sectioned channels and three types of packings — granite full-spheres, Raschig rings and meshes of stainless steel. For each type of matrix, optimum range of rotation speeds ensures the maximum effectiveness while allowing the minimum aerodynamic resistance to be determined.
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Sangplung, S., and J. A. Liburdy. "Effect of Dynamic Contact Angle on Single/Successive Droplet Impingement." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41603.

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Successive droplet impingement onto a solid surface is numerically investigated using a CFD multiphase flow model (VOF method). The main focus of this study is to better understand the hydrodynamics of the non-splash impingement process, particularly the effect of a dynamic contact angle and fluid properties along with the interaction between successive droplets while they are impinging onto a solid surface. The pre-impact droplet conditions are prescribed based on a spherical droplet diameter, velocity, and inter-droplet spacing. The molecular kinetic theory is used to model the dynamic contact angle as a function of a contact line velocity. The numerical scheme is validated against experiment results. In the impact spreading and receding processes, results are analyzed to determine the nondimensional deformation characteristics of both single and successive droplet impingements with the variation of fluid properties such as surface tension and dynamic viscosity. These characteristics include spreading ratio, spreading velocity, and a dynamic contact angle. The inclusion of a dynamic contact angle is shown to have a major effect on droplet spreading. In successive droplet impingement, the second drop causes a surge of spreading velocity and contact angle with an associate complex recirculating flow near the contact line after it initially impacts the preceding droplet when it is in an advancing condition. This interaction is less dramatic when the first drop is receding or stationary. The surface tension has the most effect on the maximum spreading radius in both single and successive droplet impingements. In contrast to this, the viscosity directly affects the damping of the spreading-receding process.
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9

Schobeiri, T. "A General Computational Method for Simulation and Prediction of Transient Behavior of Gas Turbines." In ASME 1986 International Gas Turbine Conference and Exhibit. American Society of Mechanical Engineers, 1986. http://dx.doi.org/10.1115/86-gt-180.

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This paper describes a general computational method for predicting the dynamic behavior of gas turbines and their components during transient processes of the most varied kinds. Starting from the conservation laws of fluid and thermodynamics, formulas are derived with which non-stationary processes in the most important components of the gas turbine can be accurately predicted. As an example, the transient behavior of an open-cycle gas turbine with extreme changes in load is calculated. The comparison between the calculations and measurements demonstrates the accuracy and the reliability of the computational method. Although this method has so far been applied only to a broad range of power-generating gas turbines extending from open-cycle turbines to air storage turbines, it is also suitable for the simulation of aircraft gas turbines.
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10

Liaghat, M., A. Abdollahi, F. Daneshmand, and T. Liaghat. "Wavelet Analysis of the Pressure Fluctuations of Bottom Outlet of Kamal-Saleh Dam." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12745.

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Non-stationary signals are frequently encountered in a variety of engineering fields. The inability of conventional Fourier analysis to preserve the time dependence and describe the evolutionary spectral characteristics of non-stationary processes requires tools which allow time and frequency localization beyond customary Fourier analysis. The spectral analysis of non-stationary signals cannot describe the local transient features due to averaging over the duration of the signal [1]. The Fourier Transform (FT) and the short time Fourier transform (STFT) have been often used to measure transient phenomena. These techniques yield good information on the frequency content of the transient, but the time at which a particular disturbance in the signal occurred is lost [2, 3]. Wavelets are relatively new analysis tools that are widely being used in signal analysis. In wavelet analysis, the transients are decomposed into a series of wavelet components, each of which is a time-domain signal that covers a specific octave band of frequency. Wavelets do a very good job in detecting the time of the signal, but they give the frequency information in terms of frequency band regions or scales [4]. The main objective of this paper is to use the wavelet transform for analysis of the pressure fluctuations occurred in the bottom-outlet of Kamal-Saleh Dam. The “Kamalsaleh Dam” is located on the “Tire River” in Iran, near the Arak city. The Bottom Outlet of the dam is equipped with service gate and emergency gate. A hydraulic model test is conducted to investigate the dynamic behavior of the service gate of the outlet. The results of the calculations based on the wavelet transform is then compared with those obtained using the traditional Fast Fourier Transform.
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