Browsing by Subject "Simulation methods."

Now showing 1 - 7 of 7

Open Access
A 3D garment design and simulation system
(2004) Durupınar, Funda
In this thesis study, a 3D graphics environment for virtual garment design and simulation is presented. The proposed system enables the three dimensional construction of a garment from its two dimensional cloth panels, for which the underlying structure is a mass-spring model. Construction of the garment is performed through cutting, boundary smoothing , seaming and scaling. Afterwards, it is possible to do fitting on virtual mannequins like in the real life as if in a tailor’s workshop. The behavior of cloth under different environmental conditions is implemented applying a physically-based approach. As well as the simulation of the draping of garments, efficient and realistic visualization of garments is an important issue in cloth modelling. There are various material types and reflectance properties for fabrics. We have implemented a number of material and rendering options such as knitwear, woven cloth and standard shading methods such as Gouraud shading. Performance results of the system are presented at the end.
Open Access
Animation of dressed virtual humans
(2004) Kabul, İlknur Kaynar
In this study, we present a system that enables the simulation of a dressed virtual human with different motion behaviors. The proposed system is composed of three modules: human body motion module, garment design module, and garment simulation module. The human body motion module enables the user to design different motion behaviors by adjusting the motion patterns for each body part. The garment design module consists of creating garment patterns, setting their sizes, and cutting them by removing particles. The adjustment of garment patterns onto human body is achieved by seaming garment patterns while applying cloth deformation and collision handling. Garment simulation module provides animation of virtual humans with the garments on. The main problem in garment simulation is collision handling between the animated virtual human and its garments. This study focuses on this problem. Collision detection calculations are reduced by using bounding volumes for both virtual human and garments. In addition, for avoiding edge-edge collision detection, a heuristic that constructs a very thin volume around the human body is applied. For the collision response, penalty forces and constraints are applied depending on the distance between the particle and the triangle’s plane, and the particle’s position with respect to triangle. Visual results and performance experiments produced by the implementation are presented.
Open Access
Evaluation of mobilization and deployment plan of a Turkish armored battalion via simulation
(2001) Müslüm, Selim
As being ready for war as soon as possible and with minimum casualties during the crises is the first mission for the troops, the Mobilization and Deployment Plan arises as one of the most important topic for Army. Because this plan includes all the activities that troops have to execute for responding against enemy immediately. In this study, the performance of existing Mobilization and Deployment Plan of a Turkish Armored Battalion is evaulated via simulation. The Mobilization and Deployment simulation model allows military operation planners to build models of Mobilization and Deployment operation of troops early in decision process; perform bottleneck analysis and take necessary measures against the problem areas; and perform risk management of the operations before conducting the real ones. In this thesis, our objectives are to evaulate the Mobilization and Deployment system of an Armored Battalion, find out the significant factors of enemy threat on the existing system, detect the most hazardous border and the most hazardous factor for each border, and discover the system limits. The output of the model is analysed by experimental design, and ranking and selection procedures. The code of simulation model is written in ARENA simulation program.
Open Access
Image information mining using spatial relationship constraints
(2012) Karakuş, Fatih
There is a huge amount of data which is collected from the Earth observation satellites and they are continuously sending data to Earth receiving stations day by day. Therefore, mining of those data becomes more important for effective processing of collected multi-spectral images. The most popular approaches for this problem use the meta-data of the images such as geographical coordinates etc. However, these approaches do not offer a good solution for determining what those images contain. Some researches make a big step from the meta-data based approaches in this area by moving the focus of the study to content based approaches such as utilizing the region information of the sensed images. In this thesis, we propose a novel, generic and extendable image information mining system that uses spatial relationship constraints. In this system, we use not only the region content, but also relationships of those regions. First, we extract the region information of the images and then extract pairwise relationship information of those regions such as left, right, above, below, near, far and distance etc. This feature extraction process is defined as a generic process which is independent from how the region segmentation is obtained. In addition to these, since new features and new approaches are continuously being developed by the image information mining researchers, extendability feature of the our system plays a big role while we are designing our system. In this thesis, we also propose a novel feature vector structure in which a feature vector consists of several sub-feature vectors. In the proposed feature vector structure, each sub-feature vector can be exclusively selected to be used for search process and they can have different distance metrics to be used in comparisons between the same sub-feature vector of the other feature vector structures. Therefore, the system gives ability to users to choose which information about the region and its pairwise relationship with other regions to be used when they perform a search on the system. The proposed system is illustrated by using region based retrieval scenarios on very high spatial resolution satellite images.
Open Access
Improving the performance of similarity joins using graphics processing unit
(2012) Korkmaz, Zeynep
The similarity join is an important operation in data mining and it is used in many applications from varying domains. A similarity join operator takes one or two sets of data points and outputs pairs of points whose distances in the data space is within a certain threshold value, ". The baseline nested loop approach computes the distances between all pairs of objects. When considering large set of objects which yield too long query time for nested loop paradigm, accelerating such operator becomes more important. The computing capability of recent GPUs with the help of a general purpose parallel computing architecture (CUDA) has attracted many researches. With this motivation, we propose two similarity join algorithms for Graphics Processing Unit (GPU). To exploit the advantages of general purpose GPU computing, we rst propose an improved nested loop join algorithm (GPU-INLJ) for the speci c environment of GPU. Also we present a partitioning-based join algorithm (KMEANS-JOIN) that guarantees each partition can be joined independently without missing any join pair. Our experiments demonstrate massive performance gains and the suitability of our algorithms for large datasets.
Open Access
Particle based modeling and simulation of natural phenomena
(2010) Bayraktar, Serkan
This thesis is about modeling and simulation of fluids and cloth-like deformable objects by the physically-based simulation paradigm. Simulated objects are modeled with particles and their interaction with each other and the environment is defined by particle-to-particle forces. We propose several improvements over the existing particle simulation techniques. Neighbor search algorithms are crucial for the performance efficiency and robustness of a particle system. We present a sorting-based neighbor search method which operates on a uniform grid, and can be parallelizable. We improve upon the existing fluid surface generation methods so that our method captures surface details better since we consider the relative position of fluid particles to the fluid surface. We investigate several alternatives of particle interaction schema (i.e. Smoothed Particle Hydrodynamics, the Discrete Element Method, and Lennard-Jones potential) for the purpose of defining fluid-fluid, fluid-cloth, fluid-boundary interaction forces. We also propose a practical way to simulate knitwear and its interaction with fluids. We employ capillary pressure–based forces to simulate the absorption of fluid particles by knitwear. We also propose a method to simulate the flow of miscible fluids. Our particle simulation system is implement to exploit parallel computing capabilities of the commodity computers. Specifically, we implemented the proposed methods on multicore CPUs and programmable graphics boards. The experiments show that our method is computationally efficient and produces realistic results.
Open Access
Physical simulation of wood combustion by using particle system
(2010) Gürcüoğlu, Gizem
In computer graphics, the most challenging problem is modeling natural phenomena such as water, re, smoke etc. The reason behind this challenge is the structural complexity, as the simulation of natural phenomena depends on some physical equations that are di cult to implement and model. In complex physically based simulations, it is required to keep track of several properties of the object that participates in the simulation. These properties can change and their alteration may a ect other physical and thermal properties of object. As one of natural phenomena, burning wood has various properties such as combustion reaction, heat transfer, heat distribution, fuel consumption and object shape in which change in one during the duration of simulation alters the e ects of some other properties. There have been several models for animating and modeling re phenomena. The problem with most of the existing studies related to re modeling is that decomposition of the burning solid is not mentioned, instead solids are treated only as fuel source. In this thesis, we represent a physically based simulation of a particle based method for decomposition of burning wood and combustion process. In our work, besides being a fuel source, physical and thermal a ects of combustion process over wood has been observed. A particle based system has been modelled in order to simulate the decomposition of a wood object depending on internal and external properties and their interactions and the motion of the spreading re according to combustion process.