Sharif Digital Repository

The production of υ(1S), υ(2S), and υ(3S) is investigated in pPb and pp collisions at centre-of-mass energies per nucleon pair of 5.02 TeV and 2.76 TeV, respectively. The datasets correspond to integrated luminosities of about 31 nb-1 (pPb) and 5.4pb-1 (pp), collected in 2013 by the CMS experiment at the LHC. Upsilons that decay into muons are reconstructed within the rapidity interval |ycm| < 1.93 in the nucleonnucleon centre-of-mass frame. Their production is studied as a function of two measures of event activity, namely the charged-particle multiplicity measured in the pseudorapidity interval |η| < 2.4, and the sum of transverse energy deposited at forward pseudorapidity, 4.0 < |η| <... 

The main attempt of this paper is to present a new methodology to model a generic low-level flight close to terrain, which guarantees terrain collision avoidance. Benefiting the advantages of high-speed computer technology, this method uses satellite elevation maps to generate so called 'Quad-tree forms'. The latter is then used to find the optimal trajectories for low-level flights. The novelty of this approach, entitled the 'cost map', lies in the integration of aircraft dynamics into the segmented map. This procedure results in some near-optimal trajectories with respect to aircraft dynamics that could easily be used for minimization of flight path together with pilot effort. Different... 

Recent developments in the space industry and the great tendency to define efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of multiple satellites control methods is the subject of the present paper. In this paper, two linear robust control strategies are applied to position control system of certain satellites in the virtual structure formation flight. The proposed controllers are designed considering different parametric uncertainties such as semimajor axis and eccentricity changes as well as some disturbances like second term of gravitational acceleration function (j2) and drag... 

A real-time collision warning system based on TLC1 computation is proposed. Multi-frame lane detection and analysis are adopted to make the TLC calculation algorithm more reliable. The proposed system is robust because of its capability to calculate the TLC in different brightness. The presented system can be used in an intelligent vehicle for warning or lateral control. Experimental results show that the proposed algorithm, calculates TLC acceptably. © 2004 IFAC  

This paper investigates the influence of collision angle on the interface characteristics and mechanical properties of magnetic pulse welded AA4014 tubes/Cu rods. It is shown that the collision angle, which affects the collision velocity, plays a crucial role in controlling the thickness of intermetallic compounds (IMC) layer and defect formation at the weld interface. The creation of a thin and continuous IMC layer at the weld interface is responsible for the higher load-bearing capacity of the sample welded under a collision angle of 4°. The welds made at higher collision angles are featured by a thick IMC layer containing defects such as micro-cracks, pores and cavities, which reduced the... 

The suppression of the individual Υ(nS) states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp data sets used in the analysis correspond to integrated luminosities of 150μb -1 and 230nb-1, respectively, collected in 2011 by the CMS experiment at the LHC, at a center-of-mass energy per nucleon pair of 2.76TeV. The Υ(nS) yields are measured from the dimuon invariant mass spectra. The suppression of the Υ(nS) yields in PbPb relative to the yields in pp, scaled by the number of nucleon-nucleon collisions, RAA, is measured as a function of the collision centrality. Integrated over centrality, the RAA values are 0.56±0.08(stat)±0.07(syst),... 

Abstract: The production of Z bosons is studied in the dimuon and dielectron decay channels in PbPb and pp collisions at (Formula presented.) TeV, using data collected by the CMS experiment at the LHC. The PbPb data sample corresponds to an integrated luminosity of about 166 μb−1, while the pp data sample collected in 2013 at the same nucleon-nucleon centre-of-mass energy has an integrated luminosity of 5.4 pb−1. The Z boson yield is measured as a function of rapidity, transverse momentum, and collision centrality. The ratio of PbPb to pp yields, scaled by the number of inelastic nucleon-nucleon collisions, is found to be 1.06 ± 0.05 (stat) ± 0.08 (syst) in the dimuon channel and 1.02 ± 0.08... 

Path planning is crucial in constructability analysis and heavy construction equipment scheduling, particularly in industrial plants. The main purpose of construction equipment path planning is devising the shortest path between its initial and aimed location. This suggested path is supposed to be safe, and collision-free. The current planning practice, even in industrial projects whose sites are extremely congested, is manual based on the expert judgment. Thus, this sophisticated manual process is not only prone to errors, but also time-consuming. This research presents an automated path planning approach based on an obstacle avoidance technique in robotics to support the decision-making... 

We study the collision detection of n moving balls of arbitrary sizes in 3-dimensional space. We improve both the storage and the event-handling time of the best existing KDS [1] by several logarithmic factors. Precisely, our KDS maintains O(n) certificates at the current time, uses O(nlog2⁡n) storage, handles each event in O(log3⁡n) time, and processes O(n2) events in the worst case, assuming that the balls follow constant-degree algebraic trajectories. © 2021 Elsevier B.V  

We study the collision detection of n moving balls of arbitrary sizes in 3-dimensional space. We improve both the storage and the event-handling time of the best existing KDS [1] by several logarithmic factors. Precisely, our KDS maintains O(n) certificates at the current time, uses O(nlog2⁡n) storage, handles each event in O(log3⁡n) time, and processes O(n2) events in the worst case, assuming that the balls follow constant-degree algebraic trajectories. © 2021 Elsevier B.V  

There are many reported researches considering movement behavior of vehicles. In these studies the two basic types of movement of a vehicle are longitudinal movement, car following, and lateral movement, lane changing. Dependency between car following and lane changing models and the fact that many of drivers does not consider driving lanes, necessitate developing of models that combine the car following and lane changing without considering the driving lanes. Utilizing computer simulation, the work can also be applied to conditions where lane disciplines are strictly observed. Microscopic simulation models considering the movement of individual vehicles in a traffic stream can be... 

The objective of this paper is to provide a stochastic framework to optimally avoid collision between a maneuverable spacecraft and a space object or debris. The satellite collision can be caused through a cyber-attack on a satellite by colliding it with a considered strategic satellite. Consequently, it is highly imperative that critical operational space assets be provided with autonomous collision avoidance systems. The collision avoidance methodology proposed in this paper will reduce the collision probability to an acceptable level and protect the satellite against indirect kinetic cyber-attacks initiated by designing optimal collision avoidance maneuvers using a stochastic model... 

In this paper, a new method is proposed for solving the obstacle avoidance problem of discretely actuated hyper-redundant manipulators. In each step of the solution, the closest collision to the base is removed and then the configuration of the next part of the manipulator is modified without considering the obstacles. This process is performed repeatedly until no collision is found. The Suthakorn method is applied to solve the inverse kinematics problem. Two new ideas are proposed to reduce the errors of this method: the two-by-two searching method, and iterations. To verify the proposed method, some problems are solved numerically for 2D and 3D manipulators, each in two different obstacle... 

The interaction of laser pulses of picosecond duration and terawatt to petawatt power accelerated for the very fast undistorted plasma blocks for deuterium DD or deuterium tritium fast ignition is investigated. Based on the direct and instant conversion of laser energy into mechanical motion by nonlinear (ponderomotive) forces, any thermal pressure generation is delayed by the collision process. Following the studying of the classical collision frequency, it is found that the quantum modified collision at higher energies results in a correction by about 15% reduction of the delay  

In collisional and ponderomotive predominant regimes, the propagation of microwave in rectangular waveguide filled with collisional plasma is investigated numerically. The dominant mode is excited through an evacuated waveguide and then enters a similar and co-axis waveguide filled with plasma. In collisional predominant regime, the amplitude of electric field is oscillated along propagation path; outset of propagation path due to the electron-ion collision, the intensity oscillations are reduced. Afterward, under competition between the collisional nonlinearity and absorption, the intensity is increased, so the electron density peak is created in middle of waveguide. In ponderomotive... 

Traffic collisions are one of the most important challenges threatening the general health of the world. Iran's crash statistics demonstrate that approximately 16,500 people lose their lives every year due to road collisions. According to the traffic police of Iran, heavy vehicles (including trailers, trucks, and panel trucks) contributed to 20.5% of the fatal road traffic collisions in the year 2013. This highlights the need for devoting special attention to heavy vehicle drivers to further explore their driving characteristics. In this research, the effect of heavy vehicle drivers' behavior on at-fault collisions over three years has been investigated with an innovative approach of... 

The performance is presented of the reconstruction and identification algorithms for electrons and photons with the CMS experiment at the LHC. The reported results are based on proton-proton collision data collected at a center-of-mass energy of 13 TeV and recorded in 2016-2018, corresponding to an integrated luminosity of 136 fb-1. Results obtained from lead-lead collision data collected at √sNN=5.02 TeV are also presented. Innovative techniques are used to reconstruct the electron and photon signals in the detector and to optimize the energy resolution. Events with electrons and photons in the final state are used to measure the energy resolution and energy scale uncertainty in the...