Kinds Of Collisions Research Articles

‘Dance of Agency’

Rather than diminishing design to a mechanical process governed by utility, efficiency and economy, this paper conceptualises the architecture of the Basilica of La Sagrada Família in Barcelona as posthuman. The Cathedral’s social, cultural and psychological implications will be considered in this paper. La Sagrada Família is an “unfinished cathedral” in Catalonia built by the architect Antoni Gaudí in 1882. It receives over 3 million visitors a year. Considering La Sagrada Família under the posthumanist lens enables it to be intertwined with the environment and technology. Posthumanism involves delegating particular acts of human agency into technological devices. Using Kenneth Frampton’s concept of architecture dealing with the tension between its ‘representational’ and its ‘ontological’ dimensions, this article highlights how posthumanism can enable new design methods to be integrated with the Cathedral’s original ideas, casting a reassessment of existing theories of design. This article also considers other theories of design and architecture. These are Andrew Pickering’s concept of the ‘mangle,’ Jonathan Hale’s rematerialisation theory, Steve Tomasula’s concept of human scale in architecture, and Francesca Ferrando’s theory of philosophical posthumanism. The paper explores the process of bringing the original architectural idea of La Sagrada Família to expression in material reality. It analyses how the construction of increasingly sophisticated technological devices is a kind of collision and interaction between human goals, material resistance and future sustainability. Finally, the article demonstrates how the ‘dance of agency’—an ongoing, open-ended and temporally structured operation involving a dialectic of resistance and accommodation—can be carried out using the posthumanist theory of future sustainability in order to transform La Sagrada Família into a shared, plural, hopeful architecture that is embodied and entangled.

A warning framework for avoiding vessel‐bridge and vessel‐vessel collisions based on generative adversarial and dual‐task networks

AbstractThe vessel‐bridge and vessel‐vessel collisions are likely to occur on the river. For avoiding the two kinds of collisions, a video‐based framework about early warning is proposed in this paper, which mainly contains vessel positioning, vessel trajectory data augmentation, and trajectory anomaly detection and prediction. At first, a real‐time vessel positioning method is proposed based on homography. In this method, the buoys are used as the control points, whose instantaneous world coordinates are obtained based on aerial photography, for solving the homography. Based on the obtained homography, the pixel coordinates of the identified vessel center can be mapped to the corresponding world coordinates, which realizes the vessel positioning. Second, the trajectory generative adversarial networks with multiple critics (TGANs‐MC) is proposed to enrich the historical trajectories, especially the abnormal trajectories. TGANs‐MC contains a generator and multiple critics. The generator is based on a recurrent neural network (RNN) for generating the variable‐length trajectory sequence. The critic uses 1D convolution and 1D adaptive pooling to obtain the trajectory feature. Multiple critics with different structures are used in TGANs‐MC to guide the generator to generate diverse trajectories. Third, a dual‐task network is proposed to find the vessels with abnormal trajectories for warning vessel‐bridge collision and predict the trajectories of vessels for warning vessel‐vessel collision. The dual‐task network adopts the structure of an RNN‐based encoder‐decoder, and it has two branches so that it can jointly perform the dual tasks. The anomaly detection branch uses supervised binary classification and outputs the risk degree. The attention mechanism is adopted in the prediction branch. Finally, a real‐time collision warning system is developed, which is applied on a bridge.

Energy-collision-aware Minimum Latency Aggregation Scheduling for Energy-harvesting Sensor Networks

The emerging energy-harvesting technology enables charging sensor batteries with renewable energy sources, which has been effectively integrated into Wireless Sensor Networks (EH-WSNs). Due to the limited energy-harvesting capacities of tiny sensors, the captured energy remains scarce and differs greatly among nodes, which makes the data aggregation scheduling problem more challenging than that in energy-abundant WSNs. In this article, we investigate the Minimum Latency Aggregation Scheduling (MLAS) problem in EH-WSNs. First, we identify a new kind of collision in EH-WSNs, named as energy-collision, and design several special structures to avoid it during data aggregation. To reduce the latency, we try to choose the parent adaptively according to nodes’ transmission tasks and energy-harvesting ability, under the consideration of collisions avoidance. By considering transmitting time, residual energy, and energy-collision, three scheduling algorithms are proposed under protocol interference model. Under physical interference model, several approximate algorithms are also designed by taking account of the interference from the nodes several hops away. Finally, the theoretical analysis and simulation results verify that the proposed algorithms have high performance in terms of latency.

Two-dimensional vortex quantum droplets get thick

We study two-dimensional (2D) vortex quantum droplets (QDs) trapped by a thicker transverse confinement with a⊥>1μm. Under this circumstance, the Lee-Huang-Yang (LHY) term should be described by its original form in the three-dimensional (3D) configuration. Previous studies have demonstrated that stable 2D vortex QDs can be supported by a thin transverse confinement with a⊥≪1μm. In this case, the LHY term is described by a logarithm. Hence, two kinds of confinement features result in different mechanisms of the vortex QDs. The stabilities and characteristics of the vortex QDs must be re-identified. In the current system, we find that stable 2D vortex QDs can be supported with topological charge number up to at least 4. We reformulated their density profile, chemical potential and threshold norm for supporting the stable vortex QDs according to the new condition. Unlike the QDs under thin confinement, the QDs in the current system strongly repel each other because the LHY term features a higher-order repulsion than that of the thin confinement system. Moreover, elastic and inelastic collisions between two moving vortex QDs are studied throughout the paper. Two kinds of collisions can be characterized by exerting different values of related speed. The dynamics of the stable nested vortex QD, which is constructed by embedding one vortex QD with a smaller topological number into another vortex QD with a larger number of topological charge, can be supported by the system.

Online Path Generation and Navigation for Swarms of UAVs

With the growing popularity of unmanned aerial vehicles (UAVs) for consumer applications, the number of accidents involving UAVs is also increasing rapidly. Therefore, motion safety of UAVs has become a prime concern for UAV operators. For a swarm of UAVs, a safe operation cannot be guaranteed without preventing the UAVs from colliding with one another and with static and dynamically appearing, moving obstacles in the flying zone. In this paper, we present an online, collision-free path generation and navigation system for swarms of UAVs. The proposed system uses geographical locations of the UAVs and of the successfully detected, static, and moving obstacles to predict and avoid the following: (1) UAV-to-UAV collisions, (2) UAV-to-static-obstacle collisions, and (3) UAV-to-moving-obstacle collisions. Our collision prediction approach leverages efficient runtime monitoring and complex event processing (CEP) to make timely predictions. A distinctive feature of the proposed system is its ability to foresee potential collisions and proactively find best ways to avoid predicted collisions in order to ensure safety of the entire swarm. We also present a simulation-based implementation of the proposed system along with an experimental evaluation involving a series of experiments and compare our results with the results of four existing approaches. The results show that the proposed system successfully predicts and avoids all three kinds of collisions in an online manner. Moreover, it generates safe and efficient UAV routes, efficiently scales to large-sized problem instances, and is suitable for cluttered flying zones and for scenarios involving high risks of UAV collisions.

Mechanism Change in the Dynamics of the O' + O2 → O'O + O Atom Exchange Reaction at High Collision Energies.

The extreme velocity and the large available energy of atoms with hyperthermal kinetic energies can give rise to novel mechanisms and behavior of chemical reactions unseen at thermal conditions. Crossed-molecular-beams experiments combined with isotope labeling on the reaction of hyperthermal O atoms with O2 molecules have provided an example of the arising complexity of such systems. Quasiclassical trajectory (QCT) calculations proved to be instructive in the exploration of the microscopic mechanism of the reactive and inelastic scattering observed, and a new mechanism has been identified: there are reactive collisions in which the potential energy remains repulsive during the entire encounter ("direct" reactions in which, in a sense, no complex is formed). In this work, the effect of the magnitude of the collision energy on this mechanism is explored. At hyperthermal collision energies, the reaction is characterized by a unique impact parameter window favorable for reaction through complex formation, while the direct collisions take place exclusively at small impact parameters. In direct reactive collisions, contributing as much as 12% to the reaction cross section, first the existing bond is broken, and the new bond is formed afterward. This kind of collision is unique to extremely high collision energies. Analysis of various correlations was used to find out the details of the reaction dynamics. The observed phenomena indicate that when the collision energy is extremely high, one can expect deviation from what an extrapolation from the more familiar energy ranges would predict.

Improvement of the Neutron Production Rate of IEC Fusion Device by the Fusion Reaction on the Inner Surface of the IEC Chamber

Neutrons are generated in the inertial electrostatic confinement (IEC) device through different types of fusion reactions of the fuel gas such as deuterium (D) and tritium (T). Fusion in the IEC device takes place via various kinds of collisions like beam-beam collision, beam–background gas collision, and beam-target collision on the electrode surfaces. Two identical anodes for the IEC chamber made from titanium (Ti) and SUS-316L stainless steel (SS) are used to study the effect of the anode material on the neutron production rate (NPR). The NPRs from the chambers are measured at different applied powers. The achieved NPRs, so far, for Ti and SS are 8.9 × 107 n/s at 5.25 kW (75 kV, 70 mA) and 2.8 × 107 n/s at 10.5 kW (70 kV, 150 mA), respectively. The normalized NPR (NPR rated to the cathode current) from the Ti chamber is three to four times higher than that from the SS chamber. We observed a better NPR for the Ti chamber compared with the SS chamber. This is explained by the fusion reaction occurring between the neutrals and D atoms adsorbed/embedded on the inner surface of the anode. Moreover, the Ti chamber shows an improvement of the NPR as a function of the operating time ranging from 1.5 to 1.75 after 25 h from the first discharge.

Prospective and Monetary Effectiveness Assessment Method for Advanced Driver Assistance Systems-Usage of Naturalistic Driving Studies and Experimental System Tests

This paper offers a comprehensive overview of a prospective and monetary effectiveness assessment method for advanced driver assistance systems using naturalistic driving studies and experimental system tests for a field-projected effectiveness of monetarily relevant collisions-parking and maneuvering. Research shows that this kind of collision is responsible for up to 40% of all insurance claims and for up to 30% of all claim costs worldwide. Therefore, this paper describes a monetary and prospective method for assessment based on an in-depth insurance accident database, experimental tests or simulations and naturalistic driving studies that evaluate the monetary effectiveness of an advanced driver assistance system.

A METHOD OF SEQUENTIAL SEARCHING OF OCCURANCES IN TEXT WITH THE ACCOUNT OF POSSIBLE COLLISIONS

One of the fundamental tasks of modern computer information systems is processing of symbol information, the amount of which prevails in the total amount of information. At present, rules-based approach is effectively applied to the tasks of processing symbol information. The paper deals with the peculiarities of text search applying rules-based approach. The main essence of the approach is to find pattern occurrences in the text and possible implementation of substitution (text modification). Meanwhile, when implementing search for occurrences, various kinds of collisions may arise. They should be taken into account to solve the set tasks correctly. For example, algorythms of sequential word matching can run into collisions which involve the possibility of skipping positions of pattern occurrence in a word with some structural peculiarities. The paper presents a method of searching taking into account possible collisions developed by the authors, as well as algorithmic and automatic models of the method. The developed method involves patterm markup and setting a sequence of its viewing in the form of algorithm diagram. Three algorythms (implementation variants) of the method have been developed. Algorithms differ in the possibility to carry out transition to this oк that position of the pattern and the text depending on the result of matching (equality or inequality of the current symbols of the patten and text). An automation model of the method has been developed. The proposed method of sequential matching with the pattern with collisions elimination increases the effectiveness of the computer system when implementing search procedures and symbol information processing. The method can be used in the systems of symbol information processing.

Colliding drops as coalescing and fragmenting liquid springs

A universal modelling approach of drop fragmentation after head-on drop collisions is presented. In this approach, the colliding drops are seen as liquid springs that coalesce, compress and relax, leading the merged drop to break up if it reaches a critical aspect ratio. Combining energetic balance of the compression and relaxation phases with a Rayleigh-like criterion, we deduce the fragmentation threshold velocity for the collision of two and three drops of the same liquid and of two drops of immiscible liquids. Predictions and experimental results obtained for these three kinds of collisions using various liquids and drop sizes are found to be in good agreement over a wide domain whose boundaries are discussed.

Numerical Investigation of Plasma Sheath Under Multiple Oscillations in Acceleration Region of Hall Thrusters

Oscillations range from KHz-GHz have been measured in the experimental measurements within the laboratory Hall thruster. With the various frequency oscillations, different kinds of collisions between particles and the complex electromagnetic field environment, the dynamics of particles in the discharge chamber are really intricate. The dynamics of particles become even untraceable in the near-wall region where the plasma sheath exists. In this study, the two-dimensional fully kinetic Immersed Finite Element Particle-In-Cell (IFE-PIC) numerical models are developed in the axial-radial (z-r) plane at the acceleration region, with the intent of examining the effects of multiple oscillations on the plasma sheath. The results are valuable for understanding the features of plasma sheath in acceleration region at the real working conditions.

Probabilistic Threat Assessment with Environment Description and Rule-based Multi-Traffic Prediction for Integrated Risk Management System

The objective of this paper is to propose an original probabilistic threat assessment method to predict and avoid all possible kinds of collision in multi-vehicle traffics. The main concerns in risk assessment can be summarized as three requirements: 1) a description of a traffic situation containing the geometric description of the road, dynamic and static obstacle tracking, 2) a prediction of multiple traffics' reachable set under the reasonable behavior restriction, and 3) an assessment of collision risk which corresponds with driver sensitivity and can be applied to many complex situations without loss of generality. To fulfill these three requirements, the proposed algorithm for estimating the probability of collision occurrence of the ego vehicle follows the basic idea of the particle filtering and the collision probability can be numerically implemented and calculated. The overall performance of the proposed threat assessment algorithm is verified via vehicle tests in real road. It has been shown that the threat assessment performance for the given driving situations can be significantly enhanced by the proposed algorithm. And this enhancement of risk assessment performance led to capabilities improvement of driver assistance functions of ADASs.

Collisions near Kerr black holes: lower limit of energy between orbiting and incoming particles

In our paper we investigate the lower limit of collisional energy of test particles near the Kerr black hole. In particular we examine the minimal Lorentz factor between the freely falling particles and the particles orbiting around a black hole. We consider collisions on the innermost stable circular orbit and examine near-extreme case, where collisions take place near an event horizon. By fine-tuning the particles’ angular momentum, the Lorentz factor of the collision can always be minimized to a value dependent on the black hole’s spin. We identified that this minimal value is always less than frac{2sqrt{2}-1}{sqrt{3}} and more than frac{sqrt{12}-1}{sqrt{6}} (the limits are the values for an extreme Kerr and Schwarzschild, respectively). It implies that this kind of collisions of compact objects are expected to be highly energetic near supermassive black holes. In addition, we show that an interaction between black hole’s and particle’s spins has an influence on minimal Lorentz factor. This contribution is nonnegligible for near-extreme black holes. We also discuss the relation between our results and sci-fi movie Interstellar.

Numerical investigation on particle mixing in a ball mill

Mixing behavior of particles is an essential process for a ball mill. In order to investigate particle mixing, a three dimensional model was established for particle dynamics in a ball mill. Firstly, the Discrete Element Model was adopted to track each particle in the ball mill. Meanwhile, different kinds of collisions, the relative friction for particle movement, and other conventional forces were considered. Then, the bulk movement of particles in the ball mill was explored based on the established model. In addition, the detailed characteristics of particle mixing dynamics in the ball mill were studied with multiple methods, including visual observation, collision detection, and mixing extent. It was found that the contact number of target particles increased fast in the beginning, then collapsed to one unique value when particle mixing became uniform, which finally fluctuated around the unique value periodically with the mill rotation. Moreover, multiple effects of particle size, particle density, uneven granularity and rotational velocity on particle mixing were discussed for particle mixing dynamics. In addition, selected mixing curves were present to provide more mixing information of particles in different areas of the mill. Furthermore, Boltzmann model was found to be available for mixing dynamics with the defined contact number. Additionally, selected stimulation results were compared with relative previous experimental results, and reasonable agreements could be obtained. The present work could provide consults for collision dynamics and mixing behavior of particles in ball mills.

Quantum algorithm to find invariant linear structure of MD hash functions

In this paper, we consider a special problem. "Given a function $$f$$f: $$\{0, 1\}^{n}\rightarrow \{0, 1\}^{m}$${0,1}n?{0,1}m. Suppose there exists a n-bit string $$\alpha \in \{0, 1\}^{n}$$??{0,1}n subject to $$f(x\oplus \alpha )=f(x)$$f(x??)=f(x) for $$\forall x\in \{0, 1\}^{n}$$?x?{0,1}n. We only know the Hamming weight $$W(\alpha )=1$$W(?)=1, and find this $$\alpha $$?." We present a quantum algorithm with "Oracle" to solve this problem. The successful probability of the quantum algorithm is $$(\frac{2^{l}-1}{2^{l}})^{n-1}$$(2l-12l)n-1, and the time complexity of the quantum algorithm is $$O(\log (n-1))$$O(log(n-1)) for the given Hamming weight $$W(\alpha )=1$$W(?)=1. As an application, we present a quantum algorithm to decide whether there exists such an invariant linear structure of the $$MD$$MD hash function family as a kind of collision. Then, we provide some consumptions of the quantum algorithms using the time---space trade-off.

Collision between high and low viscosity droplets: Direct Numerical Simulations and experiments

Binary droplet collisions are of importance in a variety of practical applications comprising dispersed two-phase flows. In the present work we focus on the collision of miscible droplets, where one droplet is composed of a high viscous liquid and the other one is of lower viscosity. This kind of collisions take place in, for instance, spray drying processes when droplets with different solid content collide in recirculation zones. The aim of this paper is to investigate the details of the flow inside the colliding droplets. For this purpose, two prototype cases are considered, namely the collision of equal sized droplets and the collision between a small and highly viscous droplet and a bigger low viscous droplet. A new experimental method has been developed in order to visualize the penetration and mixing process of two colliding droplets, where a fluorescence marker is added to one liquid and the droplets are excited by a laser. The results show a delay in the coalescence which takes place during the initial stage of a collision of droplets with different viscosities. Direct Numerical Simulations based on the Volume-of-Fluid method are used to study these collisions and to allow for a more detailed inspection of the mixing process. The method is extended to consider a second liquid with a different viscosity. In order to reproduce the delay of coalescence, an algorithm for the temporal suppression of the coalescence is applied. A predictive simulation of the delay is not possible, because the extremely thin air gap separating the droplets cannot be resolved by the numerics. This approach is validated by comparison with experimental data. The results provide local field data of the flow inside the collision complex, showing in particular a pressure jump at the liquid–liquid interface although no surface tension is present. The detailed analysis of the terms in the momentum balance show that the pressure jump results from the viscosity jump at the liquid–liquid interface.

Group Tower Cranes Anti-Collision Algorithm

In order to solve tower cranes interference and collision problems in the construction site, the reason of group tower cranes collision in construction site is analyzed in detail and four types of typical tower cranes collision case are summed up. The different kinds of collisions among crane rope, cargo boom and balance arm are concluded and each of the collision is analyzed detailedly. At the same time, anti-collision methods are achieved in order to prevent the collision. The best anti-collision algorithm, confirmed well in practical construction site, is chosen for the different collision case

Free collisions in a microgravity many-particle experiment. I. Dust aggregate sticking at low velocities

Over the past years the processes involved in the growth of planetesimals have extensively been studied in the laboratory. Based on these experiments, a dust-aggregate collision model was developed upon which computer simulations were based to evaluate how big protoplanetary dust aggregates can grow and to analyze which kinds of collisions are relevant in the solar nebula and are worth further studies in the laboratory. The sticking threshold velocity of millimeter-sized dust aggregates is one such critical value that have so far only theoretically been derived, as the relevant velocities could not be reached in the laboratory. We developed a microgravity experiment that allows us for the first time to study free collisions of mm-sized dust aggregates down to velocities of ∼0.1cms−1 to assess this part of the protoplanetary dust evolution model. Here, we present the results of 125 free collisions between dust aggregates of 0.5–2mm diameter. Seven collisions with velocities between 0.2 and 3cms−1 led to sticking, suggesting a transition from perfect sticking to perfect bouncing with a certain sticking probability instead of a sharp velocity threshold. We developed a model to explain the physical processes involved in dust-aggregate sticking, derived dynamical material properties of the dust aggregates from the results of the collisions, and deduced the velocity below which dust aggregates always stick. For millimeter-sized porous dust aggregates this velocity is 8×10−5ms−1.

Prunable Collision Free Random Interleaver Design

In this article we introduce a new collision free prunable random interleaver. The suggested interleaver is a joint structure involving rectangular and S-random interleaver. It comprises a general model for all kind of collision free prunable random interleavers. In addition, it can be designed for any number of parallel processors and any length of information sequence vector and can be considered also as a template for collision free prunable interleavers. The proposed interleaver can be used with all kind of turbo-like codes. The performance of the proposed interleaver is measured with parallel decodable serially concatenated convolutional codes (PDSCCCs) and compared to the PDSCCCs' performance with collision full S-random interleaver.

Dynamics of steep two-dimensional gravity–capillary solitary waves

In this paper, the unsteady evolution of two-dimensional fully nonlinear free-surface gravity–capillary solitary waves is computed numerically in infinite depth. Gravity–capillary wavepacket-type solitary waves were found previously for the full Euler equations, bifurcating from the minimum of the linear dispersion relation. Small and moderate amplitude elevation solitary waves, which were known to be linearly unstable, are shown to evolve into stable depression solitary waves, together with a radiated wave field. Depression waves and certain large amplitude elevation waves were found to be robust to numerical perturbations. Two kinds of collisions are computed: head-on collisions whereby the waves are almost unchanged, and overtaking collisions which are either almost elastic if the wave amplitudes are both large or destroy the smaller wave in the case of a small amplitude wave overtaking a large one.