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Utvärdering av algoritmer för bred kollisionsdetektering med hjälp av Boids algoritm / Evaluation of algorithms used for Broad phase collision detection using Boids algorithmNilsson, Jonathan January 2018 (has links)
Denna studie gick ut på att jämföra tre olika algoritmer som har använts för bred kollisionsdetektering, dessa algoritmer var Kd-tree, Octree och Sweep and prune. Kd-tree och Octree är spatiala datastrukturer, d.v.s. att de hanterar objekt inom specifika volymer. Sweep and prune använder istället listor för att ta reda på om objekt kolliderar. Fokus låg på att se hur stor skillnad algoritmernas exekveringstid hade jämfört med ’brute force’-implementationen och jämfört med varandra. Det utfördes ett antal olika experiment på algoritmerna med ett antal olika inställningar för att kunna utvärdera hur de presterar i olika situationer. Dessa inställningar var t.ex. antalet boids, deras hastighet och hur långt de kunde se. Resultatet visade att Sweep and prune presterade bäst med en liten mängd boids medans de andra algoritmerna kom ikapp och presterade bättre när antalet objekt ökade, då Kd-tree presterade bäst överlag. Studien kan vara till hjälp med att välja vilken bred kollisionsdetekteringsalgoritm som kan tänkas implementeras för en applikation.
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Experimental Procedures for Operational Modal Analysis of a Power Pack on a Drill RigNilsson, Oscar January 2017 (has links)
All structures have modal properties such as natural frequencies and damping. In engineeringit is often of interest to estimate these modal properties for certain structures, to be used whenmodelling for example fatigue. This is done by computing them from finite element models, by using experimental measurements or both. In the case of doing both, a finite elementmodel is usually established first and adjusted to fit measurements from experiments. Atlas Copco Rock Drills AB is the company where this thesis has been performed and the subject is experimental procedures related to estimating modal properties of the so calledpower pack, which essentially is a modularised engine and hydraulic power source of an Atlas Copco drill rig. Their current method for estimating these properties is a classical procedure which makes use of an impact hammer that an operator strikes the power pack with to induce excitation. Due to concealment of behind other parts the power pack when mounted inside the drill rig, the number of places where the operator is able to strike the power pack in is limited. Another problem with the current procedure is that it can be difficult to strike the power pack with a strong enough impulse to generate reliable results. In this thesis a new experimental procedure for Atlas Copco to use is suggested. It is based on operational modal analysis (OMA), which uses the machinery's excitation from its operational conditions to compute modal estimates. A comparison between different experimental procedures have been done and the suggested procedure is the following: excitation by engine sweep; modal identifcation by the PolyMAX method and mode shape scaling by the harmonic scaling method. An experiment was performed to compare two OMA procedures.The suggested procedure is the one that generated the better results of the two.
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Handling Sectional Views And Variational Sweep Objects In Volume-Based Automatic Reconstruction Of Solids From 2D ViewsJitendra, * 04 1900 (has links) (PDF)
No description available.
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Investigation of Chip Seal Aggregate Retention using Sweep and Long Term Performance TestingAlvarado, Alejandro Jose 11 August 2012 (has links)
Chip seals are a commonly used surface treatment used to decrease the deterioration rate of pavement surfaces. Chip seals typically consist of an application of emulsion and cover aggregate. Failure can be driven by improper strength development and inadequate bonding over time. Additionally, chip seal service life varies and long term performance prediction models are not well established. This study has two primary goals. The first goal is to investigate aggregate retention characteristics of chip seal specimens, while investigating material compatibility by means of the Sweep-M test. The second goal is to begin developing a long term performance (LTP) test to represent cores obtained from full-scale chip seal projects. Conditioning and testing protocols for LTP specimens are evaluated for representative chip seal behavior over long periods. Results confirm material interaction and favor the incorporation of sweep testing for optimum performance. Future testing is recommended for in-depth, LTP test protocol evaluation.
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Detection Likelihood Maps for Wilderness Search and Rescue: Assisting Search by Utilizing Searcher GPS Track LogsRoscheck, Michael Thomas 03 July 2012 (has links) (PDF)
Every year there are numerous cases of individuals becoming lost in remote wilderness environments. Principles of search theory have become a foundation for developing more efficient and successful search and rescue methods. Measurements can be taken that describe how easily a search object is to detect. These estimates allow the calculation of the probability of detection—the probability that an object would have been detected if in the area. This value only provides information about the search area as a whole; it does not provide details about which portions were searched more thoroughly than others. Ground searchers often carry portable GPS devices and their resulting GPS track logs have recently been used to fill in part of this knowledge gap. We created a system that provides a detection likelihood map that estimates the probability that each point in a search area was seen well enough to detect the search object if it was there. This map will be used to aid ground searchers as they search an assigned area, providing real time feedback of what has been "seen." The maps will also assist incident commanders as they assess previous searches and plan future ones by providing more detail than is available by viewing GPS track logs.
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The Aerodynamics of Low Sweep Delta WingsRullan, Jose Miguel 05 December 2008 (has links)
The aerodynamics of wings with moderately swept wings continues to be a challenging and important problem due to the current and future use in military aircraft. And yet, there is very little work devoted to the understanding of the aerodynamics of such wings. The problem is that such wings may be able to sustain attached flow next to broken-down delta-wing vortices, or stall like two-dimensional wings, while shedding vortices with generators parallel to their leading edge. To address this situation we studied the flow field over diamond-shaped planforms and sharp-edged finite wings. Possible mechanisms for flow control were identified and tested. We explored the aerodynamics of swept leading edges with no control. We presented velocity and vorticity distributions along planes normal and parallel to the free stream for wings with diamond shaped planform and sharp leading edges. We also presented pressure distributions over the suction side of the wing. Results indicated that in the inboard part of the wing, an attached vortex can be sustained, reminiscent of delta-wing type of a tip vortex, but further in the outboard region 2-D stall dominated even at 13° AOA and total stall at 21° AOA. To explore the unsteady flow field and the effectiveness of leading-edge control of the flow over a diamond-planform wing at 13° AOA, we employed Particle Image Velocimetry (PIV) at a Reynolds number of 43,000 in a water tunnel. Our results indicated that two-D-like vortices were periodically generated and shed. At the same time, an underline feature of the flow, a leading edge vortex was periodically activated, penetrating the separated flow, eventually emerging downstream of the trailing edge of the wing. To study the motion and its control at higher Reynolds numbers, namely 1.3 x 106 we conducted experiments in a wind tunnel. Three control mechanisms were employed, an oscillating mini-flap, a pulsed jet and spanwise continuous blowing. A finite wing with parallel leading and trailing edges and a rectangular tip was swept by 0°, 20°, and 40° and the pulsed jet employed as is control mechanism. A wing with a diamond-shaped-planform, with a leading edge sweep of 42°, was tested with the mini-flap. Surface pressure distributions were obtained and the control flow results were contrasted with the no-control cases. Our results indicated flow control was very effective at 20° sweep, but less so at 40° or 42°. It was found that steady spanwise blowing is much more effective at the higher sweep angle. / Ph. D.
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Heuristic Clustering Methods for Solving Vehicle Routing ProblemsNordqvist, Georgios, Forsberg, Erik January 2023 (has links)
Vehicle Routing Problems are optimization problems centered around determining optimal travel routes for a fleet of vehicles to visit a set of nodes. Optimality is evaluated with regard to some desired quality of the solution, such as time-minimizing or cost-minimizing. There are many established solution methods which makes it meaningful to compare their performance. This thesis aims to investigate how the performances of various solution methods is affected by varying certain problem parameters. Problem characteristics such as the number of customers, vehicle capacity, and customer demand are investigated. The aim was approached by dividing the problem into two subproblems: distributing the nodes into suitable clusters, and finding the shortest route within each cluster. Results were produced by solving simulated sets of customers for different parameter values with different clustering methods, namely sweep, k-means and hierarchical clustering. Although the model required simplifications to facilitate the implementation, theresults provided some significant findings. The thesis concludes that for large vehicle capacity in relation to demand, sweep clustering is the preferred method. Whereas for smaller vehicles, the other two methods perform better.
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[pt] DESENVOLVIMENTO E VALIDAÇÃO DE MÉTODO FOSFORIMÉTRICO EM SUBSTRATO DE CELULOSE PARA DETERMINAÇÃO DE PIRENO E CRISENO / [en] DEVELOPMENT AND VALIDATION OF THE PHOSPHORIMETRIC METHOD IN CELLULOSE SUBSTRATE TO DETERMINATION OF PYRENE AND CHRYSENEALESSANDRA LICURSI MAIA CERQUEIRA DA CUNHA 27 September 2007 (has links)
[pt] Neste trabalho, a fosforimetria em temperatura ambiente em
substrato
sólido (SSRTP) foi utilizada para o desenvolvimento de
método para
determinação ultra-traço e seletiva de criseno e de pireno
em amostras
complexas contendo diversos outros hidrocarbonetos
policíclicos
aromáticos (HPA). O criseno e o pireno foram selecionados
por serem
classificados pela Agência Americana de Proteção ao Meio
Ambiente
(U.S. Environmental Protection Agency - EPA) como dois dos
dezesseis
HPA poluentes prioritários e por serem conhecidos como uma
ameaça à
saúde pública e à integridade dos ecossistemas marinhos. A
capacidade
seletiva da SSRTP foi explorada por meio do efeito externo
seletivo do
átomo pesado e do ajuste de pH da solução carreadora de
solução de
analito para o substrato de celulose. O efeito da
modificação da celulose
com o surfactante SDS também foi investigado, assim como o
uso da
varredura de modo sincronizado para melhoria da resolução
espectral. O
nitrato de prata em substratos contendo SDS foi
identificado como indutor
seletivo de fosforescência do criseno em relação ao pireno
e demais HPA
em estudo (antraceno, benzo[a]pireno, 1-hidroxipireno,
fluoranteno,
fenantreno, benzo[ghj]perileno e 1,2 benzoantraceno). Já o
pireno foi
determinado seletivamente com varredura convencional e
sincronizada de
fosforescência em substratos contendo nitrato de chumbo
como indutor
seletivo e soluções carreadoras de analito em meio básico
(pH 12). Essa
seletividade foi em relação aos HPA citados, e ao 1-
hidroxipireno, mesmo
este tendo uma estrutura molecular muito semelhante a do
pireno. O planejamento fatorial foi usado, principalmente
visando verificar as
interações mútuas entre os efeitos das diferentes
variáveis do método
desenvolvido, e, conseqüentemente, a escolha da melhor
condição
experimental. Neste estudo, foram enfatizados: (i) a
análise experimental
estatística (testou-se a significância dos efeitos dos
fatores usando a
análise de variância, teste F e teste t), (ii) o uso do
método gráfico (gráfico
de Pareto) para a interpretação das interações (entre as
variáveis) e dos
resultados obtidos, assim como o refinamento do modelo, se
necessário,
excluindo variáveis irrelevantes. As características de
desempenho foram
obtidas, a fim de se validar o método proposto, obtendo
assim a
credibilidade técnica das medições. Testes estatísticos
(testes de
hipótese) com o uso de material de referência certificado
(SRM NIST
1647d) e método de referência alternativo (HPLC com
detecção por
fluorescência) também foram incluídos no processo de
validação e os
resultados encontrados estão dentro do nível de 95% de
confiança. Os
limites de detecção do criseno e do pireno em termos de
massa efetiva do
analito depositada no substrato (limite de detecção
absoluto - LDA)
encontram-se na ordem do ng. A quantificação das fontes de
variação
associadas à medição, a incerteza da medição, foi estimada
pelo ISO
GUM e método de simulação de Monte-Carlo. Testes de
seletividade com
criseno e pireno na presença de outros HPA também foram
realizados e
os resultados obtidos permitiram que a técnica fosse
utilizada para
determinações seletivas. A aplicação do método em
diferentes tipos de
matrizes (bílis de peixe e aguardente de cana) também foi
realizada e os
percentuais de recuperação encontrados foram 109 (+ -) 18%
(criseno) e 108
(+ -) 20% (pireno). Esses resultados são comparáveis com os
obtidos por
HPLC-fluorescência: 104 (+ -) 13% (criseno) e 102 (+ -) 15%
(pireno). Estudos
de caracterização, homogeneidade e estabilidade do criseno
em matriz
biológica, bílis de peixe da espécie Mugil liza, e a
estimativa da incerteza
da medição do material analisado também foram realizados.
A incerteza
da medição encontra-se na ordem do ng (referente à massa
efetiva depositada no substrato de celulose). / [en] In this work, solid surface room-temperature
phosphorimetry (SSRTP)
was used to develop ultra-trace and selective methods for
determination of
chrysene and pyrene in complex samples containing several
other
polycyclic aromatic hydrocarbons (PAHs). Both chrysene and
pyrene were
selected because they are classificated by the U.S.
Environmental
Protection Agency (EPA) as two out of the sixteen major
pollutants,
affecting public health and marine ecosystems. The
selective capability of
SSRTP was explored through the selective external heavy
atom effect and
the adjustment of pH of the analyte solution used to carry
out the analyte
to the cellulose substrate. Cellulose modification with
the use of the
surfactant sodium dodecyl sulphat (SDS) has also been
evaluated as well
as the use of synchronous scanning to improve its spectral
resolution.
Silver nitrate together with SDS was identified as
selective
phosphorescence inducer for chrysene in the presence of
pyrene and
other PAHs which are being studied (anthracene, benzo[a]
pyrene, 1-
hidroxipyrene, fluoranthene, phenanthrene, benzo[ghi]
perylene and 1,2
benzoanthracene). On the other hand, pyrene was
selectively determined
with synchronous and conventional phosphorescence scanning
in
substrates treated with lead nitrate as a selective
inducer and using
analyte carrier solution with pH 12. This selectivity
towards pyrene was
achieved in the presence of all the other tested PAHs,
including the 1-
hidroxipyrene, even though they have quite similar
molecular structures. A
factorial design was applied in order to verify mutual
interactions among factors of the different variables and
to find the best experimental
conditions. It has been emphasized in this study: (i)
statistical experimental
analysis (testing the significance of the factors using
the analysis of
variation, F-test and t-test), (ii) graphic method
(Pareto´s chart) to the
interpretation and evaluation of the interactions among
all the variables
and obtained results, the model was refined whenever
necessary so
exclude irrelevant variables. After choosing the best
experimental
condition, the performance characteristics were obtained
validating the
proposed method. Statistical tests were applied in order
to compare
results obtained using a standard reference material
analysis (NIST SRM
1647d). The proposed method was also compared with a
reference
analytical technique (HPLC with fluorescence detection)
and the results
obtained are within 95% confidence level. Chrysene and
pyrene absolute
detection limits were found in the ng order. The
quantification of the
variation sources associated to the measurement (the
measurement´s
uncertainty) was estimated based on ISO GUM and Monte-Carlo
simulation method. Selectivity tests for chrysene and
pyrene, in presence
of the other PAHs were also performed. The methods were
applied to
different types of samples (fish bilis and spirit drink
from sugar cane) and
the recoveries were 109 (+ -) 18% (chrysene) and 108 (+ -) 20%
(pyrene) by
SSRTP. These results are comparable to ones obtained by
HPLCFluorescence:
104 (+ -) 13% (chrysene) and 102 (+ -) 15% (pyrene).
Characterization, homogeny and stability studies in a
biological matrix (fish
bilis of the type Mugil liza) and the estimation of
uncertainty of the
analysed material were also done. The measurement
uncertainty was
found in ng order (in terms of the effective mass deposit
in the cellulose
substrate).
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Parallellism och prestanda : Hur parallellism påverkar exekveringstiden för Sweep and prune / Parallellism and performance : How parallelism affects the execution time of Sweep and pruneNilsson, David, Lindfors, Patrik January 2024 (has links)
Detta arbete undersöker hur exekveringstiden för Sweep and Prune påverkas av parallellism i en dataorienterad programmeringsmiljö. Specifikt analyseras vilka prestandaökningar (eng:speedups) som erhålls vid användning av olika antal exekveringstrådar. Undersökningen motiveras av svårigheten att uppskatta prestandaökningar i praktiska sammanhang på grund av overhead som uppstår av parallelliseringsprocessen. För att besvara frågeställningen implementeras en parallelliserad version av Sweep and Prune med hjälp av Unitys jobbsystem. I en experimentmiljö framtagen i Unity DOTS utvärderas implementationen under exekvering med en, två, fyra, åtta respektive 16 exekveringstrådar. Resultatet visar att algoritmen presterar bättre ju fler exekveringstrådar som används, där den 16-trådade versionen uppvisar en prestandaökning motsvarande faktor 5,61. Vidare observeras att den relativa förbättringsfaktorn sjunker i takt med ökat trådantal, vilket stämmer överens med Amdahls lag. I fortsatta arbeten rekommenderas att studien återskapas i andra utvecklingsmiljöer för att vidare undersöka det underliggande ramverkets påverkan på parallellisering och prestanda.
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Membrane sweeping at term to promote spontaneous labour and reduce the likelihood of a formal induction of labour for postmaturity: a systematic review and meta-analysisAvsiyovski, H., Haith-Cooper, Melanie, Scally, Andy J. 04 October 2018 (has links)
Yes / The aim of this study was to evaluate the efficacy and the safety of membrane sweeping in promoting spontaneous labour and reducing a formal induction of labour for postmaturity. Based on articles published between 2005 and 2016, 12 electronic databases were searched. Relative risk (RR) and its 95% confidence interval (CI) were used as pooled statistics. A total of seven studies consisting of 2252 participants were selected for the review and meta-analysis. The results revealed that membrane sweeping is advantageous in promoting spontaneous labour (RR = 1.205, 95% CI: 1.133–1.282, p = <.001), and reducing the formal induction of labour for postmaturity (RR = 0.523, 95% CI: 0.409–0.669, p = <.001). The studies reported several varying outcomes for both maternal and foetal morbidities; meta-analyses were performed where possible on each of these and found there to be no statistically significant differences in outcome between the intervention and control groups.
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