Papers by Keyword: Sampling

Abstract: With Eulerian Method of Moment (MoM) solvers for the CFD simulation of multi-phase fluid flow, the positions of bubbles or droplets are not modeled explicitly, but through scalar fields of moments. These fields can be interpreted as probability density functions describing the distribution of bubble locations. To enable intuitive visualization that allows direct visual comparisons between simulation and physical experiment, explicit instances of the bubble distribution are required. In this work, we examine one sampling-based method for obtaining sets of bubble positions from density fields. Based on an example dataset, we study the influence of the main parameter, the kernel size, on the resulting bubble set. We identify a tradeoff between numerical accuracy and temporal continuity for the visualization.

Abstract: The current situation of contact insulation systems from 80s and 90s is fallback and they do not correspond with current valid technical norm. The almost case is necessary refurbishment of building envelope or performance of additional insulation. The question "what ETICS hides inside" occurs, and whether the removal is necessary or whether the making of additional insulation directly on the current one is possible. This is connected with occurring of growth microorganism especially mold through building envelope. Our article is about problem of mold through building envelope esp. ETICS in territory of Czech Republic. The results show that the whole ETICS is contaminated with mold and there is a risk that if there are appropriate conditions for the fungus in building envelope and the newly remade ETICS will be attacked, then it will be the danger to the health of the users of building. In our research, we have evaluated and verified sampling method for the characterization of biodeteriogens which are accessible and user friendly for public.

Abstract: Genetic algorithms are optimum algorithms which depend little on questions and are able to find global optimum.In order to implement the synthesis of musical instrument tones and modify its results,this paper proposes to use genetic algorithms to find and optimize the parameters of discrete summation synthesis.Finally,the synthesis result of Erhu instrument tones is given out in comparison with other methods.

Abstract: In order to improve the ability of independent planning for AUV (Autonomous Underwater Vehicle), a new method of motion planning based on SBMPC (Sampling Based Model Predictive Control) is proposed, which is combined with model predictive control theory. Input sampling is directly made in control variable space, and sampling data is substituted into the predictive model of AUV motion. Then surge velocity and yaw angular rate in next sampling time are obtained through calculations. If predictive states are evaluated according to the performance index previously defined, optimal prediction of AUV states in next sampling can be used to realize motion planning optimization. Effects of three sampling methods (viz. uniform sampling, Halton sampling and CVT sampling) on motion planning performance are also compared in simulations. Statistical analysis demonstrates that CVT sampling points has the most uniform coverage in two-dimensional plane when amount of sampling points is the same for three methods. Simulation results show that it is effective and feasible to plan a route for AUV by using CVT sampling and rolling optimization of MPC (Model Predictive Control).

Abstract: This article is focusing on hazardous area, where potential risk of human exposure by dangerous liquids or gasses could occur. The main idea is to prevent and avoid any accident what could happen to people, who have to do investigations in such potentially dangerous places. The European Security Strategy [ defines the five key threats: Terrorism, Proliferation of weapons of mass destruction (WMD), Regional conflicts, State failure and Organised crime. Threads are unfortunately widely spread all around the world while number of incidents and affected districts is alarmingly high, see [. The answer to question how to protect responders, security forces and investigators could be fully automated sampling device situated on mobile robot platform, which can collect samples from infected, dangerous hot zones (epicentres of incident) and surrounded areas and deliver them to laboratories. One of the key leads in designing process was procedure of manual gas sampling in mines carried out by miners and gas sampling methods described in [. Method and type of sampling was determined according of requirements of Central Mine Rescue Station (CMRS) and Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE) units. Concept was split to several parts. First division is active part or sampling core and passive element or sampling head. Second separation is according of fluid type to gas sampling (GS) and liquid sampling (LS). High priority is to obtain as modular, safe and easy - service device as possible. Prototype and calculation of compressed air consumption of sampling core is demonstrated in this article.

Abstract: Based on the nonlinear finite element theory, the disturbance conditions of deep water reservoir sediment in the process of sampling with sampler are researched by using the finite element software ADINA. Nonlinear face-face contact model between sampler and sediment is established by adopting the Mohr-Coulomb constitutive model as sediments material properties, and the friction and contact in the interface of sampler wall and sediment are well simulated. The impact load is applied, and the impact sampling finite element simulation model is obtained by nonlinear transient dynamic analysis. The condition of deformation, stress and strain in sampling sampler is well discussed, the results show that the axial compression of sediment samples is largest on the bit lip surface and is smallest in the center part of the sediment samples, the impact disturbance on the soil samples is within a small scope nearby the bits.

Abstract: This paper makes a brief introduction on the current development trend of software radio and digital down converter status. The basic theoretical knowledge: Band-pass sampling theorem, digital signal orthogonal transformation theory, multi-rate signal processing theory. Based on these theories, use MATLAB complete the design and verification of mixing module, the extraction module (CIC filter, half-band filter and FIR filters), finally verify the correctness of the design, and implement DDC.

Abstract: It is known that chemical bonding is only possible when particles with antiparallel valence electrons spins orientation collide [1, 2]. In an external magnetic field unpaired electrons spins precession around the field lines is observed. Precession frequencies of valence electrons of magnetic and nonmagnetic nuclei differ, resulting in a different probability to collide in reactive state for different isotopes. The investigations results of magnetic field influence on the carbon isotopes redistribution between carbon dioxide and disperse carbon in plasmachemical processes are given. Argon-oxygen plasma by a high-frequency generator was produced. Carbon placed into reaction zone by the high-frequency electrode evaporation. The plasmachemical reaction products quenching in the plasma flow at the sampler probe were examined. It is found that the Laval nozzle sampler is more efficient for plasma stream cooling versus the cylindrical sampler. The effects of flow rate, pressure and carbon dioxide concentration on the plasma flow cooling efficiency were estimated.

Abstract: Conventional compressed sensing is accomplished via random modulation in analog domain. In this paper, a compressed sensing method based-on digital multi-channel sampling is proposed, which is used for signal spectrum detection and evaluation. This compressed sensing method is fulfilled by random modulation in digital domain and aliasing signal spectrum to full frequency range, sampling in Nyquist frequency below followed and digital multi-channels associated signal reconstruction. Examples of experiments show this method is useful and some merits are achieved, such as reduction of hardware complexity, saved memory largely and achieved real-time data transmission.

Abstract: The application of classical gaussian mixture model to image segmentation has highly computer complexiton and have not taking into account spatial information except intensity values. A image segmentation based on Gaussian mixture model with sampling and spatially information is proposed in order to solve this problem. First, a spatial information function is defined as the neighbour information weighted class probabilities of very pixels; Secondly, the sampling theorem is given in this paper,and the size of the minimum sample has been derived according to the smallest cluster and cluster number; Finally, image pixels are sampled based on the size of the minimum sample to estimate the parameter of model , which are classifed to different clusters according to bayesian rules. The experimental results show the effectiveness of the algorithm.