Resort workers: the role of social media in connecting youth travellers and mediating the neo-tribe

<div><p>The detection of the singleton attractors is of great significance for the systematic study of genetic regulatory network. In this paper, we design an algorithm to compute the singleton attractors and pre-images of the strong-inhibition Boolean networks which is a biophysically plausible gene model. Our algorithm can not only identify accurately the singleton attractors, but also find easily the pre-images of the network. Based on extensive computational experiments, we show that the computational time of the algorithm is proportional to the number of the singleton attractors, which indicates the algorithm has much advantage in finding the singleton attractors for the networks with high average degree and less inhibitory interactions. Our algorithm may shed light on understanding the function and structure of the strong-inhibition Boolean networks.</p></div

DataSheet1_Transient synchronization stability of photovoltaics integration by singular perturbation analysis.pdf

The integration of large-scale photovoltaics (PVs) into the power grid has significantly altered the transient synchronization dynamics of traditional power systems dominated by synchronous generators (SGs) and posed great challenges to modeling and analysis of PVs integration. In this paper, the transient synchronization stability of the PV-SG system is studied using the singular perturbation technique. Firstly, a nonlinear model of a PV-SG system is established to reveal the multiscale transient synchronization characteristics. Further, the full system is decomposed into a slow subsystem and a fast subsystem by the singular perturbation technique. The fast subsystem containing the dynamics of the DC voltage control, terminal voltage control, and phase-locked loop, and the slow subsystem containing the dynamics of rotor motion can perfectly reflect the dynamics of the full system within the electromagnetic and electromechanical timescales, respectively. The proposed model provides a clearer physical picture of dynamics in the PV-SG system within the electromagnetic and electromechanical timescales. Subsequently, the stability of the slow and fast subsystems is investigated using the energy function and eigenvalue analysis methods, respectively. Meanwhile, the impacts of various operating, control, and structural parameters on the transient synchronization stability are uncovered. Different from the most existing research endeavors on the wide simulations of the PVs integration, the impact of PVs on the synchronization dynamics of SGs without considering the dynamical characteristics of the PV system, and the transient synchronization stability analyses of the PLL-based voltage source converter systems, it is the key contribution to study the transient synchronization dynamical characteristics of the PV system and its interaction with the SG under different timescales. All these are helpful and easy to extend to more complicated PV-SG systems. Finally, the analysis results are validated by extensive simulations.</p

Controllability of network.

<p>Control of by adding one node (<i>m</i> = 10) and connecting it to any one node (lower part) and any two nodes (higher part) in an ER network, the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082161#pone-0082161-g001" target="_blank">Figs. 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082161#pone-0082161-g002" target="_blank">2</a>, in contrast to the uncontrolled value of (dashed line).</p

The results of for a random ER network.

<p><i>N</i> = 200, , , and , the plot includes completely random configurations (black points), the point-to-point-positive correlation configuration (open squares), and the point-to-point-negative correlation configuration (solid squares) in (a); the single-point-positive correlation configurations and in (c); and the single-point-negative correlation configurations in (d) and in (e). (b) The histogram for random configurations. (f) vs . A remarkable finding in (e) is 's are not only very small, but also their range is very narrow, indicating one is enough in determining the networked dynamics. For more details, see the text.</p

The results of and for a scale-free network.

<p>Similar to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082161#pone-0082161-g001" target="_blank">Figs. 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082161#pone-0082161-g002" target="_blank">2</a> for a scale-free network (<i>N</i> = 200, , , and ) instead.</p

Histograms of for random configurations of a SW network.

<p>(a)–(d) <i>N</i> = 200 and with different rewiring probabilities <i>P</i>: <i>P</i> = 0.4, 0.3, 0.2, and 0.1, respectively. The open and solid squares represent the configurations of point-to-point-positive and point-to-point-negative correlations between the node masses and node degrees, respectively.</p

The results of for a random ER network.

<p>Similar to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0082161#pone-0082161-g001" target="_blank">Fig. 1</a> for the results of with the same ER network considered instead. Again the effect of one is enough appears, but this time becomes maximal for the single-point-negative correlation configuration in (d). For more details, see the text.</p

Different dynamical behaviors with the change of γ, corresponding to Fig 7.

From (a) to (f), the parameter γ′s are −0.01, −0.0152, −0.045, −0.09, −0.124 and −0.129, respectively, and Pm = 0.5 is unchanged. In (c) and (f), the system shows chaotic motion, and from (d) to (f), the system exhibits a period-doubling route to chaos.</p

DataSheet1_Describing Function Analysis of Sustained Oscillations in Grid-Tied Voltage-Source Converter With Double Saturation Limiters.pdf

Recently, with the fast development of renewable energy, various power-electronic-based devices have been widely incorporated in power systems, and controller saturation limiters have been broadly utilized, such as in voltage-source converter. It has been well recognized that these saturation limiters make sustained oscillations possible. To study the impact of saturation limiters, by considering the dynamical response of double saturation limiters in both the d-axis and q-axis of the alternating current control, this paper establishes single-input-single-output models for two novel phenomena including the double-clipped oscillation and single-clipped oscillation, based on the describing function. Then the describing-function-based Nyquist criterion is used to obtain the amplitude and frequency of the sustained oscillations. The model accuracy is verified by the electromagnetic transient simulation, and the influences of control parameters are extensively studied. All these findings clearly demonstrate that the saturation limiters play an active role in sustained oscillations in power-electronic-based power systems.</p

System collapse due to boundary crisis.

The parameters Pm = 0.5 and γ = −0.1304 are chosen quite close to but outside of the stable chaotic region (i.e., the region near the critic curve for dividing areas II and III in Fig 5). Clearly here the system exhibits chaos in the transient process, and E still keeps a finite value after the transient.</p