Статті в журналах: "Three time-Scale systems"

1

Gaitsgory, Vladimir, and Minh-Tuan Nguyen. "Averaging of three time scale singularly perturbed control systems." Systems & Control Letters 42, no. 5 (April 2001): 395–403. http://dx.doi.org/10.1016/s0167-6911(00)00111-0.

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2

AKIN, Elvan, Taher HASSAN, Özkan ÖZTÜRK, and İsmail U. TİRYAKİ. "On nonoscillatory solutions of three dimensional time-scale systems." TURKISH JOURNAL OF MATHEMATICS 43, no. 5 (September 28, 2019): 2246–61. http://dx.doi.org/10.3906/mat-1901-65.

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3

Cardin, Pedro T., Paulo R. da Silva, and Marco A. Teixeira. "Three time scale singular perturbation problems and nonsmooth dynamical systems." Quarterly of Applied Mathematics 72, no. 4 (September 17, 2014): 673–87. http://dx.doi.org/10.1090/s0033-569x-2014-01360-x.

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4

Umbría, Francisco, Javier Aracil, Francisco Gordillo, Francisco Salas, and Juan Antonio Sánchez. "Three-Time-Scale Singular Perturbation Stability Analysis of Three-Phase Power Converters." Asian Journal of Control 16, no. 5 (November 28, 2013): 1361–72. http://dx.doi.org/10.1002/asjc.818.

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5

Öztürk, Özkan, Raegan Higgins, and Georgia Kittou. "Oscillation of three-dimensional time scale systems with fixed point theorems." Filomat 35, no. 6 (2021): 1915–25. http://dx.doi.org/10.2298/fil2106915o.

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Oscillation and nonoscillation theories play very important roles in gaining information about the long-time behavior of solutions of a system. Therefore, we investigate the asymptotic behavior of nonoscillatory solutions as well as the existence of such solutions so that one can determine the limit behavior. For the existence, we use some fixed point theorems such as Schauder?s fixed point theorem and the Knaster fixed point theorem.

6

Krupa, Martin, Nikola Popović, and Nancy Kopell. "Mixed-Mode Oscillations in Three Time-Scale Systems: A Prototypical Example." SIAM Journal on Applied Dynamical Systems 7, no. 2 (January 2008): 361–420. http://dx.doi.org/10.1137/070688912.

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7

ÖZTÜRK, Özkan, and Raegan HIGGINS. "Limit behaviors of nonoscillatory solutions of three-dimensional time scale systems." TURKISH JOURNAL OF MATHEMATICS 42, no. 5 (September 9, 2018): 2576–87. http://dx.doi.org/10.3906/mat-1802-104.

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8

Öztürk, Özkan. "On the existence of nonoscillatory solutions of three-dimensional time scale systems." Journal of Fixed Point Theory and Applications 19, no. 4 (June 3, 2017): 2617–28. http://dx.doi.org/10.1007/s11784-017-0454-9.

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9

Gallavotti, G., G. Gentile, and V. Mastropietro. "Hamilton-Jacobi equation, heteroclinic chains and Arnol'd diffusion in three time scale systems." Nonlinearity 13, no. 2 (January 18, 2000): 323–40. http://dx.doi.org/10.1088/0951-7715/13/2/301.

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10

Naligama, Ch A., and O. B. Tsekhan. "Robust stabilizability and stabilization of three-time-scale linear time-invariant singularly perturbed systems with delay." Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series 59, no. 2 (July 6, 2023): 110–20. http://dx.doi.org/10.29235/1561-2430-2023-59-2-110-120.

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The objective of this study is to obtain the stabilizability conditions and a stabilizing composite state feedback control for the exponential stabilization of three-time-scale singularly perturbed linear time-invariant systems with multiple commensurate delays in the slow state variables and with two small parameters of perturbation (TSPLTISD). The stabilizability conditions and the stabilizing feedback do not depend on the small parameters and are valid for all of their sufficiently small values. The approach used in this work is the nondegenerate decoupling transformation that splits the TSPLTISD into three regularly dependent on the small parameters subsystems, which are lower in dimensions than the TSPLTISD. Further, the decoupled subsystems are approximated by three subsystems that do not depend on the small parameters. It is proven that the stabilizability of the approximating subsystems guarantees the robust (with respect to small parameters) stabilizability of the original TSPLTISD. Finally, we obtain a representation of a parameter free composite feedback control for the TSPLTISD, stabilizing it for all sufficiently small values of the parameters. A numerical example is given.

11

CHEN, Jinyue, and Yi ZHANG. "Lie Symmetry Theorem for Nonshifted Birkhoffian Systems on Time Scales." Wuhan University Journal of Natural Sciences 27, no. 3 (June 2022): 211–17. http://dx.doi.org/10.1051/wujns/2022273211.

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The Lie theorem for Birkhoffian systems with time-scale nonshifted variational problems are studied, including free Birkhoffian system, generalized Birkhoffian system and constrained Birkhoffian system. First, the time-scale nonshifted generalized Pfaff-Birkhoff principle is established, and the dynamical equations for three Birkhoffian systems under nonshifted variational problems are deduced. Afterwards, in the time-scale nonshifted variational problems, by introducing the infinitesimal transformations, Lie symmetry for free Birkhoffian system, generalized Birkhoffian system and constrained Birkhoffian system are defined respectively. Then Lie symmetry theorems for three kinds of Birkhoffian systems are deduced and proved. In the end, three examples are given to explain the applications for the results.

12

Naligama, C. A., and O. B. Tsekhan. "ASYMPTOTIC APPROXIMATIONS VALIDITY BOUNDARIES FOR DECOUPLING TRANSFORMATION OF THREE-TIME-SCALE LINEAR TIME-INVARIANT SINGULARLY PERTURBED SYSTEMS WITH DELAY." Problems of Physics, Mathematics and Technics, no. 2 (2022): 83–93. http://dx.doi.org/10.54341/20778708_2022_2_51_83.

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13

Mitchell, C. Thomas, and Roy Davis. "The Perception of Time in Scale Model Environments." Perception 16, no. 1 (February 1987): 5–16. http://dx.doi.org/10.1068/p160005.

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It has been claimed that when subjects observe differently-scaled model environments their experience of temporal duration is compressed relative to standard clock time in the same proportion as the scale of the model being observed. A series of experiments is reported in which subjects made judgements of duration while observing model environments of different scale. In each experiment, two similar model environments of different scale were presented. Three different kinds of model were used: scale model railways, sitting-room models, and abstract nonrepresentional models. Despite considerable individual variability, significant effects were obtained. Smaller scale was, up to a point, related to a compression of subjective time relative to clock time, although the effect was nowhere near as great as that previously reported. Also, when scale was reduced beyond a certain point the effect on judgements of duration was eliminated, or even reversed. It is suggested that the effect of time compression is related to differences in the density of the information to be processed in environments of different scale, and that there may be an optimum value for information density related both to the scale and to the type of environment.

14

Vasu, G., M. Siva Kumar, and M. Ramalingaraju. "Optimal least squares model approximation for large-scale linear discrete-time systems." Transactions of the Institute of Measurement and Control 40, no. 1 (May 20, 2016): 35–48. http://dx.doi.org/10.1177/0142331216649023.

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A new computationally simple and precise model approximation method is described for large-scale linear discrete-time systems. By least squares matching of a suitable number of time moment proportionals and Markov parameters about [Formula: see text] of the original higher order system within the approximate model, stable denominator polynomial coefficients of the approximate model are determined. To improvise the accuracy of the approximate model, numerator polynomial coefficients are determined by minimizing the integral squared error (ISE) between the unit impulse responses of the original system and its approximate model. A matrix formula is formulated for evaluating numerator coefficients of the approximate model that leads to minimum ISE, and also for evaluating ISE. The efficacy of the proposed method is shown by illustrating three typical numerical examples employed from the literature, and the results are compared with many familiar reduction methods in terms of the ISE and relative ISE values pertaining to impulse input. Furthermore, time and frequency responses of the original system and the respective approximate model are plotted.

15

DEHON, ANDRÉ, FRED DRENCKHAHN, THOMAS KNIGHT, and HENRY MINSKY. "THREE-DIMENSIONAL PACKAGING FOR HIGH-PERFORMANCE INTERCONNECT IN LARGE-SCALE VLSI SYSTEMS." International Journal of High Speed Electronics and Systems 06, no. 04 (December 1995): 613–30. http://dx.doi.org/10.1142/s0129156495000225.

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The transit time through the interconnect between VLSI components can be a significant fraction of the latency in a large VLSI system. In this paper we describe a scheme for dense, three-dimensional packaging of VLSI components which reduces chip-to-chip transit latencies by reducing interconnect distances. Our packaging scheme sandwiches layers of conventional printed-circuit boards between layers of packaged components to efficiently utilize all three spatial dimensions for interconnect. We introduce the key components of our stack packaging scheme and show how they combine to provide efficient housing for a large range of large-scale VLSI systems.

16

Rossini, Edward D., Martin Weinstein, and Jonathan C. Smith. "Temporal Consistency and Stability of Three Scales for Measuring Stress in Adults." Perceptual and Motor Skills 82, no. 2 (April 1996): 588–90. http://dx.doi.org/10.2466/pms.1996.82.2.588.

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We investigated the 30-min. temporal consistency and temporal stability of three focal scales for measuring stress: the Cognitive Anxiety Scale-State, the Focusing Inventory Scale-State, and the Somatic Symptom Scale-State. These scales are applicable for individually measured reduction in stress in research on outcome with older adolescents and adults. All possess excellent internal consistency. All manifested significant temporal consistency and good to excellent temporal stability over 30 min. in a nonclinical sample of 60 undergraduates. Small significant differences in means on the Cognitive Anxiety Scale-State and the Somatic Symptom Scale-State were noted. The phenomenological states associated with stress were stable and consistent over 30 min., the optimal time interval used in research on stress.

17

Vavilapalli, Sridhar, S. Umashankar, P. Sanjeevikumar, Vigna K. Ramachandaramurthy, Lucian Mihet-Popa, and Viliam Fedák. "Three-stage control architecture for cascaded H-Bridge inverters in large-scale PV systems – Real time simulation validation." Applied Energy 229 (November 2018): 1111–27. http://dx.doi.org/10.1016/j.apenergy.2018.08.059.

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18

Chen, Jin-Yue, and Yi Zhang. "Time-Scale Version of Generalized Birkhoffian Mechanics and Its Symmetries and Conserved Quantities of Noether Type." Advances in Mathematical Physics 2021 (April 26, 2021): 1–9. http://dx.doi.org/10.1155/2021/9982975.

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The time-scale version of Noether symmetry and conservation laws for three Birkhoffian mechanics, namely, nonshifted Birkhoffian systems, nonshifted generalized Birkhoffian systems, and nonshitfed constrained Birkhoffian systems, are studied. Firstly, on the basis of the nonshifted Pfaff-Birkhoff principle on time scales, Birkhoff’s equations for nonshifted variables are deduced; then, Noether’s quasi-symmetry for the nonshifted Birkhoffian system is proved and time-scale conserved quantity is presented. Secondly, the nonshifted generalized Pfaff-Birkhoff principle on time scales is proposed, the generalized Birkhoff’s equations for nonshifted variables are derived, and Noether’s symmetry for the nonshifted generalized Birkhoffian system is established. Finally, for the nonshifted constrained Birkhoffian system, Noether’s symmetry and time-scale conserved quantity are proposed and proved. The validity of the result is proved by examples.

19

Munje, Ravindra, Shuyi Lin, Guoqing Zhang, and Weidong Zhang. "Observer-Based Output Feedback Integral Control for Coal-Fired Power Plant: A Three-Time-Scale Perspective." IEEE Transactions on Control Systems Technology 28, no. 2 (March 2020): 601–8. http://dx.doi.org/10.1109/tcst.2018.2879045.

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20

Materassi, Massimo, Yenca Migoya-Orué, Sandro Maria Radicella, Tommaso Alberti, and Giuseppe Consolini. "Multi-Time-Scale Analysis of Chaos and Predictability in vTEC." Atmosphere 15, no. 1 (January 9, 2024): 84. http://dx.doi.org/10.3390/atmos15010084.

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Theoretical modelling of the local ionospheric medium (LIM) is made difficult by the occurrence of irregular ionospheric behaviours at many space and time scales, making prior hypotheses uncertain. Investigating the LIM from scratch with the tools of dynamical system theory may be an option, using the vertical total electron content (vTEC) as an appropriate tracer of the system variability. An embedding procedure is applied to vTEC time series to obtain the finite dimension (m∈N) of the phase space of an LIM-equivalent dynamical system, as well as its correlation dimension (D2) and Kolmogorov entropy rate (K2). In this paper, the dynamical features (m,D2,K2) are studied for the vTEC on the top of three GNSS stations depending on the time scale (τ) at which the vTEC is observed. First, the vTEC undergoes empirical mode decomposition; then (m,D2,K2) are calculated as functions of τ. This captures the multi-scale structure of the Earth’s ionospheric dynamics, demonstrating a net distinction between the behaviour at τ≤24h and τ≥24h. In particular, sub-diurnal-scale modes are assimilated to much more chaotic systems than over-diurnal-scale modes.

21

Gu, Panpan, Senping Tian, and Qian Liu. "Decentralized iterative learning control for switched large-scale systems." Transactions of the Institute of Measurement and Control 41, no. 4 (July 23, 2018): 1045–56. http://dx.doi.org/10.1177/0142331218783249.

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This paper is concerned with the iterative learning control problem for switched large-scale systems. According to the characteristics of the systems, a decentralized D-type iterative learning control law is proposed for such switched large-scale systems. The proposed controller of each subsystem relies only on local output variables, without any information exchanges with other subsystems. By using the contraction mapping method, it is shown that the algorithm can guarantee that the output of each subsystem converges to the desired trajectory over the whole time interval along the iteration axis. Finally, three numerical examples are given to illustrate the effectiveness of the proposed algorithm.

22

Paulsen, Martin Oen. "Long time well-posedness of Whitham–Boussinesq systems." Nonlinearity 35, no. 12 (November 8, 2022): 6284–348. http://dx.doi.org/10.1088/1361-6544/ac8e4b.

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Abstract Consideration is given to three different full dispersion Boussinesq systems arising as asymptotic models in the bi-directional propagation of weakly nonlinear surface waves in shallow water. We prove that, under a non-cavitation condition on the initial data, these three systems are well-posed on a time scale of order O ( 1 ε ) , where ɛ is a small parameter measuring the weak nonlinearity of the waves. For one of the systems, this result is new even for short time. The two other systems involve surface tension, and for one of them, the non-cavitation condition has to be sharpened when the surface tension is small. The proof relies on suitable symmetrizers and the classical theory of hyperbolic systems. However, we have to track the small parameters carefully in the commutator estimates to get the long time well-posedness. Finally, combining our results with the recent ones of Emerald provide a full justification of these systems as water wave models in a larger range of regimes than the classical (a, b, c, d)-Boussinesq systems.

23

Zeng, Wenjun, Zichuan Yi, Xichen Zhou, Yiming Zhao, Haoqiang Feng, Jianjun Yang, Liming Liu, Feng Chi, Chongfu Zhang, and Guofu Zhou. "Design of Driving Waveform for Shortening Red Particles Response Time in Three-Color Electrophoretic Displays." Micromachines 12, no. 5 (May 19, 2021): 578. http://dx.doi.org/10.3390/mi12050578.

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Three-color electrophoretic displays (EPDs) have the advantages of multi-color display and low power consumption. However, their red particles have the disadvantage of long response time. In this paper, a driving waveform, which is based on electrophoresis theory and reference gray scale optimization, was proposed to shorten the response time of red particles in three-color EPDs. The driving waveform was composed of erasing stage, reference gray scale forming stage, red driving stage, and white or black driving stage. Firstly, the characteristics of particle motion were analyzed by electrophoresis theory and Stokes law. Secondly, the reference gray scale of the driving waveform was optimized to shorten the distance between red particles and a common electrode plate. Finally, an experimental platform was developed to test the performance of the driving waveform. Experimental results showed that the proposed driving waveform can shorten the response time of red particles by 65.57% and reduce the number of flickers by 66.67% compared with the traditional driving waveform.

24

Kathania, Hemant Kumar, Sudarsana Reddy Kadiri, Paavo Alku, and Mikko Kurimo. "Using Data Augmentation and Time-Scale Modification to Improve ASR of Children’s Speech in Noisy Environments." Applied Sciences 11, no. 18 (September 10, 2021): 8420. http://dx.doi.org/10.3390/app11188420.

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Current ASR systems show poor performance in recognition of children’s speech in noisy environments because recognizers are typically trained with clean adults’ speech and therefore there are two mismatches between training and testing phases (i.e., clean speech in training vs. noisy speech in testing and adult speech in training vs. child speech in testing). This article studies methods to tackle the effects of these two mismatches in recognition of noisy children’s speech by investigating two techniques: data augmentation and time-scale modification. In the former, clean training data of adult speakers are corrupted with additive noise in order to obtain training data that better correspond to the noisy testing conditions. In the latter, the fundamental frequency (F0) and speaking rate of children’s speech are modified in the testing phase in order to reduce differences in the prosodic characteristics between the testing data of child speakers and the training data of adult speakers. A standard ASR system based on DNN–HMM was built and the effects of data augmentation, F0 modification, and speaking rate modification on word error rate (WER) were evaluated first separately and then by combining all three techniques. The experiments were conducted using children’s speech corrupted with additive noise of four different noise types in four different signal-to-noise (SNR) categories. The results show that the combination of all three techniques yielded the best ASR performance. As an example, the WER value averaged over all four noise types in the SNR category of 5 dB dropped from 32.30% to 12.09% when the baseline system, in which no data augmentation or time-scale modification were used, was replaced with a recognizer that was built using a combination of all three techniques. In summary, in recognizing noisy children’s speech with ASR systems trained with clean adult speech, considerable improvements in the recognition performance can be achieved by combining data augmentation based on noise addition in the system training phase and time-scale modification based on modifying F0 and speaking rate of children’s speech in the testing phase.

25

Shimjith, Sreyas Rajagopal, Akhilanand Pati Tiwari, and Bijnan Bandyopadhyay. "Design of Fast Output Sampling Controller for Three-Time-Scale Systems: Application to Spatial Control of Advanced Heavy Water Reactor." IEEE Transactions on Nuclear Science 58, no. 6 (December 2011): 3305–16. http://dx.doi.org/10.1109/tns.2011.2170850.

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26

Chowdhury, Pranali Roy, Sergei Petrovskii, and Malay Banerjee. "Effect of Slow–Fast Time Scale on Transient Dynamics in a Realistic Prey-Predator System." Mathematics 10, no. 5 (February 23, 2022): 699. http://dx.doi.org/10.3390/math10050699.

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Systems with multiple time scales, often referred to as `slow–fast systems’, have been a focus of research for about three decades. Such systems show a variety of interesting, sometimes counter-intuitive dynamical behaviors and are believed to, in many cases, provide a more realistic description of ecological dynamics. In particular, the presence of slow–fast time scales is known to be one of the main mechanisms resulting in long transients—dynamical behavior that mimics a system’s asymptotic regime but only lasts for a finite (albeit very long) time. A prey–predator system where the prey growth rate is much larger than that of the predator is a paradigmatic example of slow–fast systems. In this paper, we provide detailed investigation of a more advanced variant of prey–predator system that has been overlooked in previous studies, that is, where the predator response is ratio-dependent and the predator mortality is nonlinear. We perform a comprehensive analytical study of this system to reveal a sequence of bifurcations that are responsible for the change in the system dynamics from a simple steady state and/or a limit cycle to canards and relaxation oscillations. We then consider how those changes in the system dynamics affect the properties of long transient dynamics. We conclude with a discussion of the ecological implications of our findings, in particular to argue that the changes in the system dynamics in response to an increase of the time scale ratio are counter-intuitive or even paradoxical.

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Thongtan, Thayathip, Pawit Tirawanichakul, and Chalermchon Satirapod. "Precise Receiver Clock Offset Estimations According to Each Global Navigation Satellite Systems (GNSS) Timescales." Artificial Satellites 52, no. 4 (December 1, 2017): 99–108. http://dx.doi.org/10.1515/arsa-2017-0009.

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Abstract Each GNSS constellation operates its own system times; namely, GPS system time (GPST), GLONASS system time (GLONASST), BeiDou system time (BDT) and Galileo system time (GST). They could be traced back to Coordinated Universal Time (UTC) scale and are aligned to GPST. This paper estimates the receiver clock offsets to three timescales: GPST, GLONASST and BDT. The two measurement scenarios use two identical multi-GNSS geodetic receivers connected to the same geodetic antenna through a splitter. One receiver is driven by its internal oscillators and another receiver is connected to the external frequency oscillators, caesium frequency standard, kept as the Thailand standard time scale at the National Institute of Metrology (Thailand) called UTC(NIMT). The three weeks data are observed at 30 seconds sample rate. The receiver clock offsets with respected to the three system time are estimated and analysed through the geodetic technique of static Precise Point Positioning (PPP) using a data processing software developed by Wuhan University - Positioning And Navigation Data Analyst (PANDA) software. The estimated receiver clock offsets are around 32, 33 and 18 nanoseconds from GPST, GLONASST and BDT respectively. This experiment is initially stated that each timescale is inter-operated with GPST and further measurements on receiver internal delay has to be determined for clock comparisons especially the high accuracy clock at timing laboratories.

28

Teng, Hsu-Feng, James M. Done, Cheng-Shang Lee, Huang-Hsiung Hsu, and Ying-Hwa Kuo. "Large-Scale Environmental Influences on Tropical Cyclone Formation Processes and Development Time." Journal of Climate 33, no. 22 (November 15, 2020): 9763–82. http://dx.doi.org/10.1175/jcli-d-19-0709.1.

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AbstractThe development of tropical cloud clusters (TCCs) to tropical cyclones (TCs) is the process of TC formation. This study identifies five main environmental transitions for the development of TCCs to TCs in the western North Pacific by using a cluster analysis method. Of these, three transitions indicate TCCs that develop in monsoon environments and two in easterly environments. Their numbers, distributions, and interannual variability differ. On average, the development time, defined as the period from the TCC forming to it developing into a TC, for TCCs that develop in easterly environments is shorter than that in monsoon environments. For the development of TCC to TC in easterly environments, TCCs have fewer embedded mesoscale convective systems (MCSs), which are located closer to the TCC center. Moreover, there is a stronger inward short-term (less than 10 days) angular momentum flux (AMF) at middle levels (800–500 hPa) before TCC formation. Conversely, in monsoon environments, TCCs have more MCSs, which are located farther from the TCC center. A stronger inward short-term AMF at low levels (1000–850 hPa) is observed before TCC formation and develops upward during the development of TCC to TC. The characteristics of MCS and AMF are significantly correlated with the development time of TCC to TC. In summary, large-scale easterly and monsoon environments cause TCCs to have different MCS and AMF characteristics, leading to higher efficiency for TCCs developing into TCs in easterly environments compared to monsoon environments.

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Gao, Jialong, Quan Liu, Hao Chen, Hanqiang Deng, Lun Zhang, Lei Sun, and Jian Huang. "Digital Battle: A Three-Layer Distributed Simulation Architecture for Heterogeneous Robot System Collaboration." Drones 8, no. 4 (April 18, 2024): 156. http://dx.doi.org/10.3390/drones8040156.

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In this paper, we propose a three-layer distributed simulation network architecture, which consists of a distributed virtual simulation network, a perception and control subnetwork, and a cooperative communication service network. The simulation architecture runs on a distributed platform, which can provide unique virtual scenarios and multiple simulation services for the verification of basic perception, control, and planning algorithms of a single-robot system and can verify the distributed collaboration algorithms of heterogeneous multirobot systems. Further, we design simulation experimental scenarios for classic heterogeneous robotic systems such as unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs). Through the analysis of experimental measurement data, we draw several important conclusions: firstly, the replication time characteristics and update frequency characteristics of entity synchronization in our system indicate that the replication time of entity synchronization in our system is relatively short, and the update frequency can meet the needs of multirobot collaboration and ensure the real-time use and accuracy of the system; secondly, we analyze the bandwidth usage of data frames in the whole session and observe that the server side occupies almost half of the data throughput during the whole session, which indicates that the allocation and utilization of data transmission in our system is reasonable; and finally, we construct a bandwidth estimation surface model to estimate the bandwidth requirements of the current model when scaling the server-side scale and synchronization-state scale, which provides an important reference for better planning and optimizing of the resource allocation and performance of the system. Based on this distributed simulation framework, future research will improve the key technical details, including further refining the coupling object dynamic model update method to support the simulation theory of the coupling relationship between system objects, studying the impact of spatiotemporal consistency of distributed systems on multirobot control and decision making, and in-depth research on the impact of collaborative frameworks combined with multirobot systems for specific tasks.

30

Simard, SJ. "Fire Severity, Changing Scales, and How Things Hang Together." International Journal of Wildland Fire 1, no. 1 (1991): 23. http://dx.doi.org/10.1071/wf9910023.

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The paper describes attributes of space, time, and process in terms of their relations to wildland fire. It then presents a generic framework, based on eight interrelated scale classes for space, time, and process. The effects of changing scales are discussed in a wildland fire context. A five-layered (society, management, systems, fire, and weather), three-dimensional structure for wildland fire is presented. The paper also discusses inefficiencies and inadequacies inherent in systems with inconsistent scales. It then focuses on the effects of scale differences between fire behavior and fire danger and on an acceptable scale range suggested by the natural evolution of these two systems. The paper then defines fire severity and proposes two types of severity models — situation and extended. Finally, it discusses fundamental differences between situational and extended severity and appropriate space, time, and process attributes for both types of severity models.

31

Badu, Shyam, Sanjay Prabhakar, and Roderick Melnik. "Coarse-Grained Models of RNA Nanotubes for Large Time Scale Studies in Biomedical Applications." Biomedicines 8, no. 7 (July 6, 2020): 195. http://dx.doi.org/10.3390/biomedicines8070195.

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In order to describe the physical properties of large time scale biological systems, coarse-grained models play an increasingly important role. In this paper we develop Coarse-Grained (CG) models for RNA nanotubes and then, by using Molecular Dynamics (MD) simulation, we study their physical properties. Our exemplifications include RNA nanotubes of 40 nm long, equivalent to 10 RNA nanorings connected in series. The developed methodology is based on a coarse-grained representation of RNA nanotubes, where each coarse bead represents a group of atoms. By decreasing computation cost, this allows us to make computations feasible for realistic structures of interest. In particular, for the developed coarse-grained models with three bead approximations, we calculate the histograms for the bond angles and the dihedral angles. From the dihedral angle histograms, we analyze the characteristics of the links used to build the nanotubes. Furthermore, we also calculate the bead distances along the chains of RNA strands in the nanoclusters. The variations in these features with the size of the nanotube are discussed in detail. Finally, we present the results on the calculation of the root mean square deviations for a developed RNA nanotube to demonstrate the equilibration of the systems for drug delivery and other biomedical applications such as medical imaging and tissue engineering.

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Pang, Chee Khiang, Gregory R. Hudas, Dariusz G. Mikulski, Cao Vinh Le, and Frank L. Lewis. "Command and Control for Large-Scale Hybrid Warfare Systems." Unmanned Systems 03, no. 01 (January 2015): 1–15. http://dx.doi.org/10.1142/s2301385015500016.

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Emerging hybrid threats in large-scale warfare systems require networked teams to perform in a reliable manner under changing mission tactics and reconfiguration of mission tasks and force resources. In this paper, a formal Command and Control (C2) structure is presented that allows for computer-aided execution of the networked team decision-making process, real-time tactic selection, and reliable mission reconfiguration. A mathematically justified networked computing environment is provided called the Augmented Discrete Event Control (ADEC) framework. ADEC is portable and has the ability to provide logical connectivity among all team participants including mission commander, field commanders, war-fighters, and robotic platforms. The proposed C2 structure is developed and demonstrated on a simulation study involving Singapore Armed Forces team with three realistic symmetrical, asymmetrical, and hybrid attack missions. Extensive simulation results show that the tasks and resources of multiple missions are fairly sequenced, mission tactics are correctly selected, and missions and resources are reliably reconfigured in real time.

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Jiang, Sanlong, Shaobo Li, Qiang Bai, Jing Yang, Yanming Miao, and Leiyu Chen. "Research on Generation Method of Grasp Strategy Based on DeepLab V3+ for Three-Finger Gripper." Information 12, no. 7 (July 8, 2021): 278. http://dx.doi.org/10.3390/info12070278.

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A reasonable grasping strategy is a prerequisite for the successful grasping of a target, and it is also a basic condition for the wide application of robots. Presently, mainstream grippers on the market are divided into two-finger grippers and three-finger grippers. According to human grasping experience, the stability of three-finger grippers is much better than that of two-finger grippers. Therefore, this paper’s focus is on the three-finger grasping strategy generation method based on the DeepLab V3+ algorithm. DeepLab V3+ uses the atrous convolution kernel and the atrous spatial pyramid pooling (ASPP) architecture based on atrous convolution. The atrous convolution kernel can adjust the field-of-view of the filter layer by changing the convolution rate. In addition, ASPP can effectively capture multi-scale information, based on the parallel connection of multiple convolution rates of atrous convolutional layers, so that the model performs better on multi-scale objects. The article innovatively uses the DeepLab V3+ algorithm to generate the grasp strategy of a target and optimizes the atrous convolution parameter values of ASPP. This study used the Cornell Grasp dataset to train and verify the model. At the same time, a smaller and more complex dataset of 60 was produced according to the actual situation. Upon testing, good experimental results were obtained.

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Layton, Roger, and Sarah Duffy. "Path Dependency in Marketing Systems." Journal of Macromarketing 38, no. 4 (July 8, 2018): 400–414. http://dx.doi.org/10.1177/0276146718787012.

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Path dependency in marketing systems occurs when what has happened at an earlier time affects the possible outcomes of a sequence of events occurring at a later point in time (Sewell 1996). Unlike the wider category of all social systems, in marketing systems path dependency is innate in the evolutionary dynamics underlying the formation and growth of a marketing system, beginning with the historical framing of choices made by all participants, generating, through self-organization and emergence, four complex social mechanisms - delivery systems, stakeholder action fields, technology evolution systems and value change fields. These complex social mechanisms interact over time generating marketing system outcomes that feedback continually into participant choices. The paper argues that all marketing systems, whether micro, meso or macro in scale and level, exhibit path dependence, and explores the implications of this finding. The paper identifies three ways of approaching path dependence in marketing systems - a narrative, partial and strong approach. It concludes that in a specific marketing systems setting all three approaches complement each other, the first establishing in narrative terms what happened, the second identifying the key path dependencies in a partial analysis, and finally, the third, drawing on a detailed or strong understanding of the causal dynamics at work to provide insights needed to extend theories of marketing system formation and growth and to provide the foundations for policy prescription. The occurrence of path dependency in all marketing systems and the complementary nature of the three distinctive approaches are the two major contributions of this paper.

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Yuan, Shenglan, Jianyu Hu, Xianming Liu, and Jinqiao Duan. "Slow manifolds for dynamical systems with non-Gaussian stable Lévy noise." Analysis and Applications 17, no. 03 (May 2019): 477–511. http://dx.doi.org/10.1142/s0219530519500027.

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This work is concerned with the dynamics of a class of slow–fast stochastic dynamical systems driven by non-Gaussian stable Lévy noise with a scale parameter. Slow manifolds with exponentially tracking property are constructed, and then we eliminate the fast variables to reduce the dimensions of these stochastic dynamical systems. It is shown that as the scale parameter tends to zero, the slow manifolds converge to critical manifolds in distribution, which helps to investigate long time dynamics. The approximations of slow manifolds with error estimate in distribution are also established. Furthermore, we corroborate these results by three examples from biological sciences.

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Mushkin, Jonathan, and Boaz Katz. "A simple random walk model explains the disruption process of hierarchical, Eccentric three-body systems." Monthly Notices of the Royal Astronomical Society 498, no. 1 (August 19, 2020): 665–73. http://dx.doi.org/10.1093/mnras/staa2492.

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ABSTRACT We study the disruption process of hierarchical three-body systems with bodies of comparable mass. Such systems have long survival times that vary by orders of magnitude depending on the initial conditions. By comparing with three-body numerical integrations, we show that the evolution and disruption of such systems can be statistically described as a simple random walk process in the outer orbit’s energy, where the energy exchange per pericenter passage (step size) is calculated from the initial conditions. In our derivation of the step size, we use previous analytic results for parabolic encounters, and average over the (Kozai–Lidov) oscillations in orbital parameters, which are faster then the energy diffusion time-scale. While similar random walk models were studied before, this work differs in two manners: (a) this is the first time that the Kozai–Lidov averaged step size is derived from first principles and demonstrated to reproduce the statistical evolution of numerical ensembles without fitting parameters, and (b) it provides a characteristic lifetime, instead of answering the binary question (stable/unstable), set by case-specific criteria.

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ZHENG, JIAN-FENG, ZI-YOU GAO, LING-XIAO YANG, and BAI-BAI FU. "SYNCHRONIZATION BEHAVIOR IN DISCRETE SYSTEMS." International Journal of Modern Physics C 22, no. 05 (May 2011): 441–48. http://dx.doi.org/10.1142/s012918311101635x.

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This work explores the synchronization behavior in discrete systems with both discrete time and discrete state. In order to describe the self-driven function of the node’s state, a state transfer matrix is introduced. Three typical network structures (random network, small-world network and scale-free network) are numerically studied in order to investigate the impact of network structure. Simulation results show that, according to the phase synchronization index, the coupling strength is divided into four regions: the increasing region, the maximum region, the decreasing region and the oscillation region. Moreover, the size of the oscillation region seems to be changeless, independent of the network structure and a parameter describing the number of total node’s states.

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SMITH, KENNY, HENRY BRIGHTON, and SIMON KIRBY. "COMPLEX SYSTEMS IN LANGUAGE EVOLUTION: THE CULTURAL EMERGENCE OF COMPOSITIONAL STRUCTURE." Advances in Complex Systems 06, no. 04 (December 2003): 537–58. http://dx.doi.org/10.1142/s0219525903001055.

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Language arises from the interaction of three complex adaptive systems — biological evolution, learning, and culture. We focus here on cultural evolution, and present an Iterated Learning Model of the emergence of compositionality, a fundamental structural property of language. Our main result is to show that the poverty of the stimulus available to language learners leads to a pressure for linguistic structure. When there is a bottleneck on cultural transmission, only a language which is generalizable from sparse input data is stable. Language itself evolves on a cultural time-scale, and compositionality is language's adaptation to stimulus poverty.

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Esteban, S., F. Gordillo, and J. Aracil. "Three-time scale singular perturbation control and stability analysis for an autonomous helicopter on a platform." International Journal of Robust and Nonlinear Control 23, no. 12 (May 10, 2012): 1360–92. http://dx.doi.org/10.1002/rnc.2823.

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QADER, Veen Sagvan, Omar Mohammed ALI, and Nawfal Idrees HASAN. "Technical, Economic and Environmental Comparison of Three Different Grid-Connected PV Tracking Systems Power Plant Under Kurdistan Region/Iraq Climate Condition." Eurasia Proceedings of Science Technology Engineering and Mathematics 17 (September 16, 2022): 102–19. http://dx.doi.org/10.55549/epstem.1176066.

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In this paper, a 1 MW grid-connected PV system was performed and simulated numerically in Zakho city, using hourly meteorological data for three systems; fixed, single-axis, and dual-axis tracking systems for solar module. The analysis of this study is based on technical, economic, and environmental feasibility. The analysis based on the actual 3 PV solar panels using different tracking systems which installed on the roof of the Engineering college of Zakho University. The evaluation findings suggest that PV technology is quite promising in this location, with annual yield factors of (1416 kWh/kW), (1694 kWh/kW), and (1902 kWh/kW) for the three systems, respectively. Furthermore, the proposed system's capacity factors are 16.2 percent, 19.3 percent, and 21.70 percent. The economic growth of a 1MW grid-connected photovoltaic (PV) system adjusted for meeting the daily peak load in Zakho is analyzed and compared based on the cost of electricity (COE), net present value (NPV), payback period (PBP), and the energy payback time (EPBT) for three systems in the present work. The COE for the three proposed systems, fixed, 1st axis, and dual axes solar tracking systems, was 0.0826 USD/kWh, 0.0489 USD/kWh, and 0.0441 USD/kWh, respectively, which indicated the tracking system is economically feasible. The findings indicate a favorable trend, implying that large-scale photovoltaics of dual-axis systems might be a feasible option for addressing future power needs.

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Griffin, R. F. "Spectroscopic Studies of Binary and Multiple Star Systems." International Astronomical Union Colloquium 135 (1992): 98–109. http://dx.doi.org/10.1017/s0252921100006187.

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There can be few subjects that benefit more than binary stars do from complementary approaches. Consider their orbits, for an initial example. By ‘visual’ methods — by which I mean all methods of obtaining angular resolution on the sky, including the modern techniques of optical interferometry — one can determine an orbit, but with the scale known in terms of angular measure only. By spectroscopic (radial-velocity) methods one obtains the linear scale of the orbit, but with those techniques the inclination to the line of sight is indeterminate. In order to find the complete characteristics of the orbit in three dimensions — as is essential in order to find those most important data, the masses of the component stars — one needs to utilize both methods. It is, accordingly, clearly of great value to have a meeting like this that is object-oriented rather than technique-oriented; it is a long time since there was a meeting specifically devoted to binary stars, and especially in view of the great advances that have taken place in observational techniques of all sorts in recent years it is more than timely that we should have this meeting now. We are certainly very grateful to Dr. McAlister and his colleagues for arranging it and holding it at this beautiful venue.

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ZANIKOLAS, SERAFEIM, and RIZOS SAKELLARIOU. "AN IMPORTANCE-AWARE ARCHITECTURE FOR LARGE-SCALE GRID INFORMATION SERVICES." Parallel Processing Letters 18, no. 03 (September 2008): 347–70. http://dx.doi.org/10.1142/s0129626408003442.

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This paper is concerned with the scalability of large-scale grid monitoring and information services, which are mainly used for the discovery of resources of interest. Large-scale grid monitoring systems have to balance between three competing performance metrics: query response time, imposed network overhead, and information freshness. Improving one of the three metrics will affect another; any solution will be based on a trade-off. The paper is motivated by the observation that existing grid monitoring systems can only be manually configured for a trade-off among the three metrics, which applies equally to all monitored resources; this implies that all resources in a grid are considered to be of equal importance. Assuming that in a large-scale grid setting this is unlikely to hold, the paper proposes an importance-based monitoring architecture for large-scale grid information services, based on an adaptation of the web crawling paradigm. The main idea is that, since not all resources are of equal importance, one can vary the trade-off based on the relative importance of the monitored resources. The proposed architecture is described and evaluated based on large-scale deployments of a prototype implementation on PlanetLab.

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Wang, Panbao, Yang Zhou, Xiaochen Zhang, Wei Wang, and Dianguo Xu. "Optimal Power Flow Scheduling Strategy for Multi-Microgrids with Multi-Time Scale Method." Journal of Solar Energy Research Updates 9 (December 20, 2022): 97–108. http://dx.doi.org/10.31875/2410-2199.2022.09.10.

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Abstract: The energy management of a multi-microgrid (MG) system is essential for its stable and economic operation. This study proposes an optimal power flow scheduling strategy for the energy management of multi-MG systems. At the multi-MG level, the global central controller (GCC) is responsible for managing the MGs. The GCC calculates the amount of power exchanged within the MGs by using a novel optimal energy allocation policy. Based on the energy supply and demand mismatch, MGs are classified as providers and consumers. The GCC collects information, then distributes energy among the consumers and divides benefits to the providers. Each consumer determines the price of the purchased energy from other microgrids based on a priority parameter, in which the local load demand and renewable energy penetration rate are considered as important factors. At the MG level, with the goal of minimising the operating cost of the MG, the energy is controlled from two time scales, namely day-ahead and intraday, to optimise the output power of generators and energy storage devices. Finally, a simulation of a multi-MG system with three MGs demonstrate the effectiveness of the proposed optimal method.

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Gerlach, J. C., K. Klöppel, C. MÜller, N. Schnoy, M. D. Smith, and P. Neuhaus. "Hepatocyte Aggregate Culture Technique for Bioreactors in Hybrid Liver Support Systems." International Journal of Artificial Organs 16, no. 12 (December 1993): 843–46. http://dx.doi.org/10.1177/039139889301601210.

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Utilizing a modified culture technique for hepatocytes, a high performance suspension culture is possible in which hepatocytes spontaneously form cell aggregates. The aggregates of 20-100 cells have been histologically confirmed to hold a three-dimensional structure, they show a long-term external metabolism and a survival time comparable with standard adhesion cultures. This technique has several advantages in the construction of large scale bioreactors for hybrid liver support systems.

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Rieger, L., J. Alex, W. Gujer, and H. Siegrist. "Modelling of aeration systems at wastewater treatment plants." Water Science and Technology 53, no. 4-5 (February 1, 2006): 439–47. http://dx.doi.org/10.2166/wst.2006.100.

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A model for the response time of aeration systems at WWTPs is proposed. It includes the delays caused by the air supply system (consisting of blowers, throttles and pipes), the rise time of the air bubbles and all control loops except the master DO controller. Beside a description of the required step-change experiments, different approaches for model calibration are given depending on the available data. Moreover, the parameters for the oxygen transfer and the response time of the aeration system model are not clearly identifiable. The model can be used for simulation studies which compare different types of controllers under changing loading and process conditions. The results from full-scale experiments at three different plants show that the response times of the aeration systems are in the range of 4–5 min. Taking all processes and time constants into account, some 30 min are needed to reach a new steady state after a step change of the airflow rate.

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Bozakova, N., V. Gerzilov, S. Popova-Ralcheva, and V. Sredkova. "Welfare assessment of three chicken breeds (Gallus Gallus Domesticus) under different production systems." Biotehnologija u stocarstvu 27, no. 4 (2011): 1705–13. http://dx.doi.org/10.2298/bah1104705b.

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The objective assessment of welfare in poultry under different rearing systems has gained an increasing importance. In particular, organic rearing systems are examined in relation to improving poultry welfare and the quality of poultry production at a worldwide scale. The aim of the present study was to assess the welfare of parent flocks - White Plymouth Rock, Barred Plymouth Rock (Line F) and New Hampshire, reared under two production systems - indoor on a litter and organic (sleep houses and walk yards). The rearing and microclimatic conditions, the poultry behaviour and blood plasma corticosterone concentrations under both farming systems were examined. The welfare assessment score of White Plymouth Rock, New Hampshire and Barred Plymouth Rock, reared indoor on a litter was 60%, whereas in an organic production system - 90%. The higher welfare of birds reared organically was determined by the greater number of birds spending their time in dust bathing (P<0.01) and feather cleaning (P<0.05) as well as by fewer episodes of aggression (P<0.01) and plasma corticosterone levels (P<0.01), as compared to chickens reared indoor on a litter.

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Kolmogorov, Oleg V., Dmitriy V. Prokhorov, Sergey S. Donchenko, and Ekaterina V. Chemesova. "A system of one- and two-way comparisons of time scales using stimulated Raman scattering." Izmeritel`naya Tekhnika, no. 6 (2020): 27–32. http://dx.doi.org/10.32446/0368-1025it.2020-6-27-32.

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Problems requiring high-precision comparisons and synchronization of time scales of remote time and frequency standards are considered. The prospects of using fiber-optic communication lines to solve these problems are considered. Data on maximum operating distances and accuracy characteristics of time scale comparison systems using fiber-optic communication lines are given. It is shown that the range of existing systems is not enough to solve a number of problems. A method for amplifying optical signals in an optical fiber using the effect of stimulated Raman scattering is considered. The application of the Raman amplifier in telecommunication systems is considered. A method is proposed for using the effect of stimulated Raman scattering (SRS) to amplify the optical signals of time scale comparison systems. A scheme is proposed for a system of one- and two-way comparisons of time scales of distant objects, using signal amplification based on the SRS effect realized using two-way counter-pumping. The principle of the system’s operation and the procedure for determining the divergence in the time scales of remote objects are described. The results of estimation of the error and range of systems of one- and two-way comparisons of time scales using Raman amplifier are presented. It is shown that the implementation of Raman-amplification in the equipment of such systems will allow more than three times to increase their range without reducing the accuracy of the systems.

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Wu, Gen-Han, Yi-Ting Chen, and Ke-Hsuan Chen. "Hybrid Algorithms for Inbound and Outbound Truck Scheduling in Cross-Docking Systems." Applied Sciences 12, no. 21 (October 28, 2022): 10931. http://dx.doi.org/10.3390/app122110931.

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A cross-docking system is a kind of facility design for the purpose of enhancing the time efficiency of a distribution center. In this study, we attempt to consider a cross-docking system without temporary storage and obtain great system performance by addressing the scheduling problem of inbound and outbound trucks, in which the total operation time of trucks is minimized. In order to reduce computational efforts, three hybrid metaheuristic approaches based on particle swarm optimization, simulated annealing, and a variable neighborhood search are proposed. By the computational experiments, the three optimized approaches are analyzed and compared with each other. The experimental results show that all of these three approaches can obtain pretty good solutions, even in the large-scale examples. Moreover, one of these approaches—a hybrid metaheuristic with particle swarm optimization and a variable neighborhood search—can usually obtain the best solutions.

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Al-Qadi, Osama, Bertus Tazifua, and Evgeniy Semenov. "Analysis of Discrete Message Transmission in Orthogonal Frequency Division Multiplexing Systems." NBI Technologies, no. 4 (2022): 5–9. http://dx.doi.org/10.15688/nbit.jvolsu.2022.4.1.

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High data transfer rates are required in modern digital radio transmission systems. But an increase in the data transfer rate leads to a deterioration in the transmission quality and a high BER (bit error rate). OFDM technology, which was introduced in the 1960s, implements all these functions. In this paper, the influence of fading channels on the transmission of information in OFDM systems is investigated. In wireless systems for transmitting discrete messages, the channel parameters greatly affect the transmission quality, as interference, noise and fading affect the useful signal. Fading is a very common phenomenon in wireless communication systems, affecting the phase shift of the signal. In an urban environment, multipath propagation of signals also takes place, since signals propagate along two or more paths before reaching the receiver. Depending on the signal propagation medium and communication conditions, small-scale fading can be distinguished. At the same time, there are significant changes in the amplitude and phase of the signal. Small-scale fading occurs on a smaller scale, comparable to the wavelength of the transmitted signal, and often changes throughout the signal path, and may change one or more times during the transmission time of the symbol, which leads to so-called flat (smooth) and frequency-selective fading. The results obtained show the effect of fading on the digital transmission system (OFDM). The three discrete message delay profiles used represent a low-, medium-, and high-latency propagation environment, respectively. A model of a wireless digital communication system (OFDM) has been built using the SystemVue software.

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Wang, Xiang, Le Guo, Jianjian Shen, Meiyan Kong, and Xu Han. "Issues and Strategies for the Dispatching and Trading of the Three Gorges Large Hydropower System." Energies 16, no. 18 (September 18, 2023): 6683. http://dx.doi.org/10.3390/en16186683.

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China’s electricity market reform has posed a real challenge to the large-scale hydropower system. Taking the world’s largest watershed hydropower system, the Three Gorges large hydropower system (TGLHS), as the engineering background, this study analyzes the issues and strategies of dispatching and trading in the electricity market. The analysis indicates that the TGLHS exhibits unique difficulties because of transprovincial and transregional power transmission. Major issues including the multi-dimensional and multi-time-scale nested allocation of hydropower energy, the bidding and performance of cascaded hydropower plants in multiple electricity markets, as well as multiple uncertainties in the runoff; electricity prices in multiple markets are also elaborated upon. The corresponding suggested strategies are proposed to cope with the aforementioned issues: (1) for multi-dimensional and multi-scale nested allocation problems, it is necessary to comprehensively consider monthly market transactions and priority generation plans, and establish a profit maximization model; (2) propose a bidding decision-making linkage and segmented bidding optimization model for cascades upstream and downstream hydropower stations; (3) construct a model for decomposing the annual and monthly planned electricity consumption curves and developing operational plans for giant cascade power stations that are suitable for cross-provincial and cross-regional power transmission and transformation; (4) a runoff, electricity price, and market distribution model has been proposed, laying the foundation for further research on multi-scale optimization models for hydropower. Finally, prospects for research on the participation of large-scale hydropower systems in the electricity market are summarized, expecting to promote the marketization of large cascaded hydropower systems. The dispatching and trading of the TGLHS implies that it is important and necessary to explore market theories and methods considering hydropower characteristics and operation needs.

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