The effect of road networks on the forest wildfires ‘size

<p>Forest roads are crucial to forest conservation. They can be perfect barriers against forest wildfires if they maintained appropriately and firefighting equipment were provided. This paper discusses the effect of forest roads in context of forest transportation and fire fighting in Czech Republic forestry. The results prove that, the wildfire sizes are reduced if the fire brigade can reach the fires more rapidly.  In other words, the wildfire sizes were evaluated from a function of the distances to roads. Increasing road density can decrease wildfire size. Enhancement of the road network can decrease the future wildfire problems as attack times strongly effects on wildfire sizes. This motivates the location of some firefighting stations close to the forest areas. Furthermore, the importance of road density, road quality and other infrastructure to attack time and efficiency, such as bridges and water reservoirs, may be enhanced. In case forest management methods, infrastructure and the capacities of fire brigades are not updated to the new climate, larger areas destroyed by wildfires can be predicted.</p><p><strong>Keywords: </strong>attack time, forest roads, forest management,<strong> </strong>forest wildfires, Czech Republic forestry.</p>

A Lightweight SDN Fingerprint Attack Defense Mechanism Based on Probabilistic Scrambling and Controller Dynamic Scheduling Strategies

Software-defined networking (SDN) decouples the control plane from the data plane, which increases network flexibility and programmability. However, the “three-layer two-interface” architecture of SDN introduces new security issues. Attackers can collect fingerprint information (such as network types, controller types, and critical flow rules) by analyzing round-trip time (RTT) distribution of test packets. In order to defend against the fingerprint attack with limited attack time, we first design a probabilistic scrambling strategy. This strategy not only interferes with the delay distribution of probe packets in attack flow but also reduces the negative impact on the performance of legal packets in normal flow. However, if fingerprint attackers have unlimited attack time, it is not enough to defend against the attack only by this strategy. Therefore, we further propose a controller dynamic scheduling strategy to change SDN fingerprint information actively. Because scheduling different types of controllers to work in different periods will generate costs, the scheduling strategy is also responsible for determining the optimal switching time point to balance security benefits and costs. At last, we implement the defense mechanism on different types of controllers and verify its effectiveness in experimental scenarios. The experimental results show that the mechanism can effectively hide the SDN fingerprint information while reducing the negative impact on network performance.

Study regarding the main ways of gaining ball possession in Romanian basketball

Introduction: In basketball, ball possession can begin and end in many different ways, for example, ball possession may begin with an out-of-bounds, a stolen ball, a rebound etc, and may also end with a throw, a turnover or when the attack time has expired.Aim: Starting from the working hypothesis that the backboard rebounds represent an important factor in gaining ball possession, we have proposed to identify and analyze the game parameters recorded in the national basketball leagues.Material and methods: The theoretical documentation included explaining, based on specialized literature, terms related to ball possession. Also, in order to accomplish the purposes of this research, we have used statistical analysis (possession, arithmetic mean, amplitude) and graphical representation. This study focused on all teams participating in the 2019-2020 season of the National Basketball Leagues (16 men’s and 13 women’s teams).Results: Following the analysis and centralization of the game parameters from the 146 games played in the men’s league and 144 games in the women’s league, we have identified the main ways of gaining ball possession.Conclusions: Backboard rebounds represent the main way of gaining ball possession (which confirms the hypothesis).

Distributed multi-munition cooperative guidance based on clock synchronization for switching and noisy networks

This paper proposes a novel three-dimensional guidance method based on clock synchronization algorithms, creatively solving the problems of randomized change, non-connection and even communication outage caused by packet loss and delay in the co-guidance of loitering munitions. The proposed method is characterized by fast convergence of the aspect angle rate in the longitudinal plane, and the attack time constrains in the lateral plane. Normal accelerations on the two sub-planes are thereby calculated, so as to control the munitions’ co-attack. Simulation experiments show that the proposed method can ensure reliable and stable asymptotic agreement of attack time expectation for the cooperative multiple munitions under the switching and noisy networks.

Research on Cooperative Strategy of Multiple Rockets

In order to enhance the penetration ability of the rocket and the damage degree of the target, the trajectory design and optimization of the rockets are carried out, and the cooperative strategy of multiple rockets is designed. Firstly, the particle motion model of rocket is established, and the power and guidance scheme are given. Then, a cooperative attack strategy based on different launch points for multiple rockets is proposed, which transforms the cooperative attack into the optimization of launch points. The optimization model of the launch point under the expected attack time is established, and the model is solved by the cultural algorithm. The distribution of the launch point under different attack time is obtained and fitted as curves under corresponding conditions. Finally, aiming at the problem of multiple rockets cooperative combat, using the obtained curves, three kinds of cooperative strategies which are suitable for different attack time requirements are proposed and verified by simulation.

Measurement of Retinal Changes in Primary Acute Angle Closure Glaucoma under Different Durations of Symptoms

Purpose. To investigate the changes of retinal nerve fiber layer (RNFL) in patients after an attack of primary acute angle closure glaucoma (PAACG) and to assess the impact of attack time on prognosis of retinal changes. Design. cross-sectional study. Methods. Twenty-six patients with unilateral PAACG attack and cataracts from 2017 to 2019 were enrolled. Eyes with PAACG attack time less than 1 day constituted the group A (n = 13), while eyes with PAACG attack time more than 1 day constituted the group B (n = 13). All patients received phacoemulsification and viscogoniosynechialysis after intraocular pressure (IOP) lowering. All patients underwent ophthalmic examinations including IOP, best-corrected visual acuity (BCVA), and visual field (VF). Optical coherence tomography angiography (OCTA) was used to obtain circumpapillary RNFL vessel density (cpVD). Spectral domain optical coherence tomography (SD-OCT) was used to examine the peripapillary RNFL and macular ganglion cell complex (GCC). All patients accepted 2 assessments before and 1 month after the procedure. Results. The IOP of all patients recovered to normal (12.77 ± 2.65 mm Hgvs. 12.77 ± 3.85 mmHg, p=0.834) after the procedure. Patients in the group A had better BCVA improvement than those in the group B (1.32 ± 0.84 vs. 0.50 ± 0.21, p=0.004), as well as better mean defect (MD) values from VF (−3.65 ± 2.54 vs −16.05 ± 5.99, p<0.001). Compared with group B, patients in the group A had thicker macula (Fovea area: 255.00 ± 27.94 μm vs. 203.92 ± 59.73 μm, p=0.010), thicker GCC (82.62 ± 8.76 μm vs. 65.23 ± 18.56 μm, p=0.005), and thicker RNFL (105.08 ± 9.38 μm vs. 77.69 ± 20.23 μm, p<0.001). Higher blood flow density in all-plexus peripapillary retina was observed in the group A eyes compared with group B (full sector: 0.56 ± 0.02 vs. 0.41 ± 0.07, p<0.001). In both groups, the association between average RNFL thickness and cpVD as well as MD values and pattern standard deviation (PSD) values from VF was stronger (R2 = 0.58, 0.60, −0.54, respectively, all p<0.001) than the association between GCC thickness and cpVD, as well as MD values and PSD values (R2 = 0.37, p=0.001; R2 = 0.37, p=0.001; R2 = −0.27, p=0.007). Conclusion. Patients with attack time less than 1 day had better retinal thickness and all-plexus peripapillary retina blood flow density. Controlling the attack time could decrease retinal damage by PAACG.

Chimpanzees use tree species with a resonant timbre for accumulative stone throwing

Animals use tools for communication relatively rarely compared to tool use for extractive foraging. We investigated the tool-use behaviour accumulative stone throwing (AST) in wild chimpanzees, who regularly throw rocks at trees, producing impact sounds and resulting in the aggregations of rocks. The function of AST remains unknown but appears to be communication-related. We conducted field experiments to test whether impact sounds produced by throwing rocks at trees varied according to the tree's properties. Specifically, we compared impact sounds of AST and non-AST tree species. We measured three acoustic descriptors related to intrinsic timbre quality, and found that AST tree species produced impact sounds that were less damped, with spectral energy concentrated at lower frequencies compared to non-AST tree species. Buttress roots in particular produced timbres with low-frequency energy (low spectral centroid) and slower signal onset (longer attack time). In summary, chimpanzees use tree species capable of producing more resonant sounds for AST compared to other tree species available.