Academic literature on the topic 'Envelope curves'
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Journal articles on the topic "Envelope curves"
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Harrow, Christopher, and Nurfatimah Merchant. "Envelope Curves Unify Sinusoidal Graphing." Mathematics Teacher: Learning and Teaching PK-12 113, no. 4 (2020): 301–8. http://dx.doi.org/10.5951/mtlt.2019.0129.
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Transferring fundamental concepts across contexts is difficult, even when deep similarities exist. This article leverages Desmos-enhanced visualizations to unify conceptual understanding of the behavior of sinusoidal function graphs through envelope curve analogies across Cartesian and polar coordinate systems.
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Huibregtse, Mark, and Adam Winchell. "Envelope curves and equidistant sets." Involve, a Journal of Mathematics 9, no. 5 (2016): 839–56. http://dx.doi.org/10.2140/involve.2016.9.839.
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Szóstak, Mariusz. "Best Fit of Cumulative Cost Curves at the Planning and Performed Stages of Construction Projects." Buildings 13, no. 1 (2022): 13. http://dx.doi.org/10.3390/buildings13010013.
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The correct planning of investment costs and the effective monitoring of implementation process are significant problems in the management of investment projects. At the stage of construction works, it is worth determining the trend of the performed cost curve and periodically testing the fitting to the scheduled course of the budgeted cost curve. The aim of this research was to determine the shape and course of the cost curves for selected construction projects. A procedure was developed to forecast the distribution of cumulative costs at the planning stage of construction projects using envelopes (spaces) and cost curves for three different types of buildings and construction sectors: collective residential buildings, hotel buildings, and commercial and service buildings. An assessment of the actual costs incurred of investment tasks was carried out, the trend of which the cumulative cash flow curves can be estimated with a large match by forecasting the construction process. The article determines the best fit curves and the spaces of cost curves (the banana envelope of the S-curve) using mathematical formulas (third-degree polynomials), along with developed graphs for various construction projects. The analysis of the author’s own research was used to determine the best-fit curve and the curve’s area, which indicates the area of the correct planning of cumulative costs of construction investments.
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Nomoto, Ken’ichi, Toshikazu Shigeyama, and Masa-aki Hashimoto. "Light Curve Models for SN 1987A and Diagnosis of Supernova Interior." International Astronomical Union Colloquium 108 (1988): 319–34. http://dx.doi.org/10.1017/s0252921100094070.
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AbstractPresupernova evolution of the progenitor of SN 1987A, hydrodynamics of explosion (shock propagation, explosive nucleosynthesis), optical light curve due to shock heating and 56Co decay, and X-ray and γ-ray light curves are calculated and compared with the observations of SN 1987A. Constraints on the mass of the hydrogen-rich envelope Menv (i.e., mass loss history) and the helium abundance in the envelope are obtained from the progenitor’s blue-red-blue evolution as well as from the light curve. The explosion energy E and the mass and distribution of 56Ni are inferred from the light curves. Models and observations are in reasonable agreement for E/Menv = 1.5 ± 0.5 × 1050 erg/M⊙, Menv = 5 - 10 M⊙, and MNi ∼ 0.07 M⊙. Mixing of 56Ni into the envelope is indicated.Light curves of exploding bare helium stars are also calculated to see whether the observed Type Ib supernova light curves can be accounted for.
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Yuan, Guohai, Yonghong Wang, Yexin Fang, Rutao Ma, Kun Ning, and Yang Tang. "High-Temperature and Pressure Downhole Safety Valve Performance Envelope Curve Study." Processes 11, no. 9 (2023): 2525. http://dx.doi.org/10.3390/pr11092525.
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The introduction of downhole safety valve performance envelope curves can effectively prevent the failure of the downhole safety valves during field operations. The method of drawing the performance envelope curve of high-temperature and pressure downhole safety value was proposed based on the mechanical properties of the downhole safety valve. The numerical simulation method was used for the mechanical performance of the downhole safety valve, and the stress change law of the overall structure of the downhole safety valve under the ultimate load was obtained. The ultimate bearing state and the failure threshold stress value of the key components of the downhole safety valve were further determined. The performance envelope curve of the downhole safety valve was finally completed. The results of the study show that the downhole safety value envelope curve can be obtained by studying the mechanical properties of the downhole safety valve, and each section of the envelope curve corresponded to the cause of failure of the downhole safety valve, giving the theoretical calculation idea of the downhole safety valve performance envelope curve. This study provides theoretical and methodological support for the study of the performance envelope curves of the downhole safety valves, packers, and other complex working conditions of downhole tools and their application in the field.
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Koshkin, Sergiy, and Ivan Rocha. "Caustics of Light Rays and Euler's Angle of Inclination." PUMP Journal of Undergraduate Research 3 (October 22, 2020): 205–25. http://dx.doi.org/10.46787/pump.v3i0.2417.
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Euler used intrinsic equations expressing the radius of curvature as a function of the angle of inclination to find curves similar to their evolutes. We interpret the evolute of a plane curve optically, as the caustic (envelope) of light rays normal to it, and study the Euler's problem for general caustics. The resulting curves are characterized when the rays are at a constant angle to the curve, generalizing the case of evolutes. Aside from analogs of classical solutions we encounter some new types of curves. We also consider caustics of parallel rays reflected by a curved mirror, where Euler's problem leads to a novel pantograph equation, and describe its analytic solutions.
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HANNIEL, I., M. RAMANATHAN, G. ELBER, and M. S. KIM. "PRECISE VORONOI CELL EXTRACTION OF FREE-FORM PLANAR PIECEWISE C1-CONTINUOUS CLOSED RATIONAL CURVES." International Journal of Computational Geometry & Applications 17, no. 05 (2007): 453–86. http://dx.doi.org/10.1142/s0218195907002446.
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We present an algorithm for generating Voronoi cells for a set of planar piecewise C1-continuous closed rational curves, which is precise up to machine precision. The algorithm starts with the symbolically generated bisectors for pairs of C1-continuous curve segments (C(t),Ci(r)). The bisectors are represented implicitly in the tr-parameter space. Then, they are properly trimmed after being split into monotone pieces. The trimming procedure uses the orientation of the original curves as well as their curvature fields, resulting in a set of trimmed-bisector segments represented as implicit curves in a parameter space. A lower-envelope algorithm is then used in the parameter space of the curve whose Voronoi cell is sought. The lower envelope represents the exact boundary of the Voronoi cell. The algorithm also supports piecewise C1-continuous curves and generates the Voronoi cell of such input curves using additional point/curve bisector segments.
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Fang, Qiliang, Keiichi Maeda, Haonan Ye, Takashi J. Moriya, and Tatsuya Matsumoto. "Diversity in Hydrogen-rich Envelope Mass of Type II Supernovae. I. Plateau Phase Light-curve Modeling." Astrophysical Journal 978, no. 1 (2024): 35. https://doi.org/10.3847/1538-4357/ad8b19.
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Abstract We present a systematic study of Type II supernovae (SNe II) originating from progenitors with effective temperatures (T eff) and luminosities closely resembling red supergiants (RSGs) observed in pre-supernova (SN) images and in the Galaxy. Using Modules for Experiments in Stellar Astrophysics, we compute a large grid of massive stars with T eff ranging from 3200 to 3800 K at their RSG phases, with hydrogen envelopes artificially stripped to varying extents (3–10 M ⊙). The light curves of SNe IIP resulting from the explosions of these Galactic-RSG–like progenitors are modeled using STELLA. Our survey of the light curves reveals that partial stripping of the hydrogen envelope creates diversity in the magnitude and duration of SNe IIP light curves, without affecting the position of the RSG progenitor on the Hertzsprung–Russell diagram. For these Galactic-RSG-like progenitor models, we establish an indicator based on the light-curve properties to estimate the hydrogen envelope mass. Additionally, we discuss the effects of material mixing and 56Ni heating. Applying our model grid to a large sample of approximately 100 observed SNe IIP reveals a considerably broader range of hydrogen-rich envelope masses than predicted by standard stellar wind models. This finding suggests that if SNe IIP are explosions of Galactic-like RSGs to explain the diversity in the observed light curves, a significant fraction of them must have experienced substantial mass loss beyond the standard mass-loss prescription prior to their explosions. This finding highlights the uncertainties involved in massive star evolution and the pre-SN mass-loss mechanism.
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Гирш and A. Girsh. "Envelope of a Family of Curves." Geometry & Graphics 4, no. 4 (2016): 14–18. http://dx.doi.org/10.12737/22839.
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A one-parameter family of algebraic curves has an
 envelope line, which may be imaginary in certain cases. Jakob
 Steiner was right, considering the imaginary images as creation of
 analysis. In the analysis a real number is just a part of a complex
 number and in certain conditions the initial real values can give an
 imaginary result. But Steiner was wrong in denying the imaginary
 images in geometry. The geometry, in contrast to the single analytical
 space exists in several spaces: Euclidean geometry operates
 only on real figures valid and does not contain imaginary figures
 by definition; pseudo-Euclidean geometry operates on imaginary
 images and constructs their images, taking into account its own
 features. Geometric space is complex and each geometric object in
 it is the complex one, consisting of the real figure (core) having the
 "aura" of an imaginary extension. Thus, any analytical figure of the
 plane is present at every point of the plane or by its real part or by
 its imaginary extension. Would the figure’s imaginary extension be
 visible or not depends on the visualization method, whether the
 image has been assumed on superimposed epures – the Euclideanpseudo-Euclidean
 plane, or the image has been traditionally assumed
 only in the Euclidean plane. In this paper are discussed cases when
 a family of algebraic curves has an envelope, and is given an answer
 to a question what means cases of complete or partial absence of
 the envelope for the one-parameter family of curves. Casts some
 doubt on widely known categorical st
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Nitta, Koh-hei, and Takashi Ishiburo. "Failure Envelope Curves in Polyethylene Solids." Macromolecular Symposia 214, no. 1 (2004): 251–60. http://dx.doi.org/10.1002/masy.200451018.
Full textDissertations / Theses on the topic "Envelope curves"
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Tagliaferri, Lorenza. "Probabilistic Envelope Curves for Extreme Rainfall Events - Curve Inviluppo Probabilistiche per Precipitazioni Estreme." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2008. http://amslaurea.unibo.it/99/.
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A regional envelope curve (REC) of flood flows summarises the current bound on our experience of extreme floods in a region. RECs are available for most regions of the world. Recent scientific papers introduced a probabilistic interpretation of these curves and formulated an empirical estimator of the recurrence interval T associated with a REC, which, in principle, enables us to use RECs for design purposes in ungauged basins.
The main aim of this work is twofold. First, it extends the REC concept to extreme rainstorm events by introducing the Depth-Duration Envelope Curves (DDEC), which are defined as the regional upper bound on all the record rainfall depths at present for various rainfall duration. Second, it adapts the probabilistic interpretation proposed for RECs to DDECs and it assesses the suitability of these curves for estimating the T-year rainfall event associated with a given duration and large T values. Probabilistic DDECs are complementary to regional frequency analysis of rainstorms and their utilization in combination with a suitable rainfall-runoff model can provide useful indications on the magnitude of extreme floods for gauged and ungauged basins.
The study focuses on two different national datasets, the peak over threshold (POT) series of rainfall depths with duration 30 min., 1, 3, 9 and 24 hrs. obtained for 700 Austrian raingauges and the Annual Maximum Series (AMS) of rainfall depths with duration spanning from 5 min. to 24 hrs. collected at 220 raingauges located in northern-central Italy. The estimation of the recurrence interval of DDEC requires the quantification of the equivalent number of independent data which, in turn, is a function of the cross-correlation among sequences. While the quantification and modelling of intersite dependence is a straightforward task for AMS series, it may be cumbersome for POT series. This paper proposes a possible approach to address this problem.
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Guse, Björn Felix. "Improving flood frequency analysis by integration of empirical and probabilistic regional envelope curves." Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2010/4926/.
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Flood design necessitates discharge estimates for large recurrence intervals. However, in a flood frequency analysis, the uncertainty of discharge estimates increases with higher recurrence intervals, particularly due to the small number of available flood data. Furthermore, traditional distribution functions increase unlimitedly without consideration of an upper bound discharge. Hence, additional information needs to be considered which is representative for high recurrence intervals.
Envelope curves which bound the maximum observed discharges of a region are an adequate regionalisation method to provide additional spatial information for the upper tail of a distribution function. Probabilistic regional envelope curves (PRECs) are an extension of the traditional empirical envelope curve approach, in which a recurrence interval is estimated for a regional envelope curve (REC). The REC is constructed for a homogeneous pooling group of sites. The estimation of this recurrence interval is based on the effective sample years of data considering the intersite dependence among all sites of the pooling group.
The core idea of this thesis was an improvement of discharge estimates for high recurrence intervals by integrating empirical and probabilistic regional envelope curves into the flood frequency analysis. Therefore, the method of probabilistic regional envelope curves was investigated in detail. Several pooling groups were derived by modifying candidate sets of catchment descriptors and settings of two different pooling methods. These were used to construct PRECs. A sensitivity analysis shows the variability of discharges and the recurrence intervals for a given site due to the different assumptions. The unit flood of record which governs the intercept of PREC was determined as the most influential aspect.
By separating the catchments into nested and unnested pairs, the calculation algorithm for the effective sample years of data was refined. In this way, the estimation of the recurrence intervals was improved, and therefore the use of different parameter sets for nested and unnested pairs of catchments is recommended.
In the second part of this thesis, PRECs were introduced into a distribution function. Whereas in the traditional approach only discharge values are used, PRECs provide a discharge and its corresponding recurrence interval. Hence, a novel approach was developed, which allows a combination of the PREC results with the traditional systematic flood series while taking the PREC recurrence interval into consideration. An adequate mixed bounded distribution function was presented, which in addition to the PREC results also uses an upper bound discharge derived by an empirical envelope curve. By doing so, two types of additional information which are representative for the upper tail of a distribution function were included in the flood frequency analysis. The integration of both types of additional information leads to an improved discharge estimation for recurrence intervals between 100 and 1000 years.<br>Abschätzungen von Abflüssen mit hohen Wiederkehrintervallen werden vor allem für die Bemessung von Extremhochwässern benötigt. In der Hochwasserstatistik bestehen insbesondere für hohe Wiederkehrintervalle große Unsicherheiten, da nur eine geringe Anzahl an Messwerten für Hochwasserereignisse verfügbar ist. Zudem werden zumeist Verteilungsfunktionen verwendet, die keine obere Grenze beinhalten. Daher müssen zusätzliche Informationen zu den lokalen Pegelmessungen berücksichtigt werden, die den Extrembereich einer Verteilungsfunktion abdecken.
Hüllkurven ermitteln eine obere Grenze von Hochwasserabflüssen basierend auf beobachteten maximalen Abflusswerten. Daher sind sie eine geeignete Regionalisierungsmethode. Probabilistische regionale Hüllkurven sind eine Fortentwicklung des herkömmlichen Ansatzes der empirischen Hüllkurven. Hierbei wird einer Hüllkurve einer homogenen Region von Abflusspegeln ein Wiederkehrintervall zugeordnet. Die Berechnung dieses Wiederkehrintervalls basiert auf der effektiven Stichprobengröße und berücksichtigt die Korrelationsbeziehungen zwischen den Pegeln einer Region.
Ziel dieser Arbeit ist eine Verbesserung der Abschätzung von Abflüssen mit großen Wiederkehrintervallen durch die Integration von empirischen und probabilistischen Hüllkurven in die Hochwasserstatistik. Hierzu wurden probabilistische Hüllkurven detailliert untersucht und für eine Vielzahl an homogenen Regionen konstruiert. Hierbei wurden verschiedene Kombinationen von Einzugsgebietsparametern und Variationen von zwei Gruppierungsmethoden verwendet. Eine Sensitivitätsanalyse zeigt die Variabilität von Abfluss und Wiederkehrintervall zwischen den Realisationen als Folge der unterschiedlichen Annahmen. Die einflussreichste Größe ist der maximale Abfluss, der die Höhe der Hüllkurve bestimmt.
Eine Einteilung in genestete und ungenestete Einzugsgebiete führt zu einer genaueren Ermittlung der effektiven Stichprobe und damit zu einer verbesserten Abschätzung des Wiederkehrintervalls. Daher wird die Verwendung von zwei getrennten Parametersätzen für die Korrelationsfunktion zur Abschätzung des Wiederkehrintervalls empfohlen.
In einem zweiten Schritt wurden die probabilistischen Hüllkurven in die Hochwasserstatistik integriert. Da in traditionellen Ansätzen nur Abflusswerte genutzt werden, wird eine neue Methode präsentiert, die zusätzlich zu den gemessenen Abflusswerten die Ergebnisse der probabilistischen Hüllkurve – Abfluss und zugehöriges Wiederkehrintervall - berücksichtigt. Die Wahl fiel auf eine gemischte begrenzte Verteilungsfunktion, die neben den probabilistischen Hüllkurven auch eine absolute obere Grenze, die mit einer empirischen Hüllkurve ermittelt wurde, beinhaltet. Damit werden zwei Arten von zusätzlichen Informationen verwendet, die den oberen Bereich einer Verteilungsfunktion beschreiben. Die Integration von beiden führt zu einer verbesserten Abschätzung von Abflüssen mit Wiederkehrintervallen zwischen 100 und 1000 Jahren.
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Guse, Björn Felix [Verfasser], and Bruno [Akademischer Betreuer] Merz. "Improving flood frequency analysis by integration of empirical and probabilistic regional envelope curves / Björn Felix Guse ; Betreuer: Bruno Merz." Potsdam : Universität Potsdam, 2010. http://d-nb.info/1218391049/34.
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Mathews, James Jr. "Curve Jets, Submanifold Families, and Envelopes." Thesis, State University of New York at Stony Brook, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10621813.
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<p> Synthetic or qualitative methods can provide insight into geometric structures not apparent from the purely analytic point of view. For example, much of the geometry of a classical surface in Euclidean space is coded in the differential topology of its family of normal lines. This thesis extends the range of applicability of such methods by developing the basic theory of submanifold families in general, emphasizing higher-order contact phenomena and making use of the modern theory of jets. A main technical contribution is, in certain cases, the calculation of invariants of parameterized submanifold jets by the reparameterization group, a construction of the quotient varieties, and compactifications of these varieties. </p><p> As applications, in 2 dimensions we deduce: - a description of projective structures by (second order) tensorial data, - a characterization of the curve families realizable by geodesics for some connection, and a description of the connections in this case, and - a linearizability criterion for curve families, including <i>d</i>-webs for <i>d</i> > 3, and in higher dimensions: - general formulas for envelopes of submanifold families, including line envelopes for visual applications, and - a characterization of the extrinsic geometry of <i>m</i>-submanifolds in projective space <b>RP</b><i><sup>n</sup></i>, for certain <i> m</i>, including a generalization of the classical Wilczynski equations for surfaces in <b>RP</b><sup>3</sup>.</p><p>
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NAIR, DEEPA. "GEAR MODELING BY SIMULATING THE FABRICATION PROCESS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115914025.
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Mina, Lee. "A Quantitative Study on Innovation in Renewable Energy Technology in Korea." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225764.
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Costa, Victor Hugo Teles. "Análise de desempenho de sistemas de comunicação OFDM-TDMA utilizando cadeias de Markov e curva de serviço." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3795.
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Previous issue date: 2013-12-06<br>This paper presents a model based on Markov Chains and enhanced with
the use of Kernel Density Estimation and of MMFM (Markov Modulated Fluid
Model) in order to evaluate the performance of the transmission link in OFDMTDMA
systems. For that purpose, traffic models based on the Kernel method and
the MMFM with adjusted autocorrelation function are proposed. From the model
implemented for the OFDM-TDMA system, it was derived equations for estimation
of QoS parameters such as delay and average queue size in the buffer. The
obtained results confirm that the proposed model is efficient in describing the link
performance indicators. The use of MMFM to model the arrival process improves
the QoS parameter estimates of the queueing model making their values very close
to those of the simulation results. It was also developed an equation to the OFDMTDMA
system’s service curve. Through this equation and the concept of Envelope
Process, it was proposed an equation to estimate the probability of buffer overflow
in OFDM-TDMA systems. The results show that the estimates of the overflow probability
based on the system’s service curve are very close to the ones obtained by
simulations and that the computational complexity to obtain them is significantly
reduced compared to the model based on Markov Chains due to the absence of
matrix computation.<br>Este trabalho apresenta um modelo baseado em Cadeias de Markov e aprimorado
com o uso do método de Kernel de estimação não-paramétrica e de MMFM
(Markov Modulated Fluid Model) com o objetivo de avaliar e descrever o desempenho
do enlace de transmissão em sistemas OFDM-TDMA. Para tal, modelos de tráfego
baseados no Método de Kernel e em MMFM com ajuste da função de autocorrelação
são propostos. A partir do modelo implementado para o sistema OFDM-TDMA,
foram obtidas equações para estimação de parâmetros de QoS como retardo e tamanho
médio da fila no buffer. Os resultados obtidos confirmam que o modelo proposto
é bastante eficiente ao descrever os indicadores de desempenho do sistema. O uso de
MMFM para modelar o processo de chegada de pacotes aprimora os estimadores de
parâmetros de QoS tornando as estimativas bem próximas dos valores obtidos com
as simulações. Também deduziu-se uma equação para a curva de serviço de Sistemas
OFDM-TDMA. Em seguida, utilizando-se desta curva de serviço e do conceito de
Processo Envelope foi proposta uma equação para estimação de probabilidade de
transbordo do buffer em sistemas OFDM-TDMA. Os resultados obtidos mostram
que as estimativas de probabilidade de transbordo baseadas na curva de serviço do
sistema se aproximam bem dos resultados da simulação e a complexidade computacional
do cálculo necessário para obtê-los é significativamente reduzida em relação
ao modelo definido utilizando Cadeias de Markov.
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Rocha, Flávio Geraldo Coelho. "Alocação de recursos em redes sem fio OFDM multiusuário utilizando modelagem multifractal adaptativa." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6617.
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Previous issue date: 2016-11-22<br>Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG<br>In this work, in order to describe network traffic characteristics, such as long-range dependence among samples, self-similarity and multiscale behavior, we propose a Multifractal Adaptive Model based on a multiscale cascade in the Wavelet Domain. We compare the proposed model performance with those of other models presented in the literature. It is also proposed an envelope process for the network traffic that takes into account parameters of the Multifractal Adaptive Model. Furthermore, we derive an equation in order to estimate the buffer overflow probability for both a simplified communication system with a single server, single queue and finite buffer, and to a wireless network multiuser scenario based on OFDM technology. To this end, we consider the service curve of the round-robin scheduling algorithm of the OFDM network. Taking into account the envelope process and the service curve we obtain, through the Network Calculus theory, the maximum delay experienced by users of the OFDM network. Moreover, assuming a similar network scenario to an LTE network, we propose a joint channel-aware and queue-aware resource scheduling algorithm. Based on the presented scheduler, we propose a minimum service curve for the LTE user and through this we propose an approach to accomplish maximum delay guarantee.<br>Neste trabalho, com o objetivo de descrever características do tráfego de redes, tais como longa-dependência entre amostras, autossimilaridade e comportamento multiescala, propõe-se um Modelo Multifractal Adaptativo baseado em uma cascata multiescala no domínio Wavelet. O desempenho do modelo proposto é comparado a outros modelos presentes na literatura. Também é proposto um processo envelope para o tráfego de redes que leva em consideração parâmetros do Modelo Multifractal Adaptativo proposto. Além disso, deduz-se uma equação para o cálculo da probabilidade de transbordo do buffer, tanto para um sistema de comunicação simplificado com servidor único, fila única e buffer finito, quanto para um ambiente multiusuário de rede sem fio baseado na tecnologia OFDM. Para tanto, utiliza-se a curva de serviço do escalonador round-robin da rede OFDM. Utilizando-se do processo envelope e da curva de serviço, obtém-se por meio do Cálculo de Rede a estimativa para o retardo máximo experimentado pelos usuários da rede OFDM. Em seguida, assume-se um ambiente de rede similar ao de uma rede LTE e propõe-se para essa rede um escalonador de recursos sensível às condições do canal de comunicação e à probabilidade de transbordo do buffer. Com base no escalonador apresentado, propõe-se uma curva de serviço mínima para o usuário da rede LTE e por meio dessa, propõe-se uma abordagem para garantia de retardo.
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Deddi, Hafsa. "Dualité géométrique et relations de correspondance entre courbes primales et duales." Phd thesis, Université Joseph Fourier (Grenoble), 1997. http://tel.archives-ouvertes.fr/tel-00004935.
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Cette thèse est une étude de base qui traite de la transformation de la dualité géométrique entre un point et un hyperplan d'un espace affine. Une étape indispensable est alors d'établir une définition rigoureuse de la dualité géométrique ainsi que ses propriétés et caractéristiques. Cette notion de dualité peut se généraliser pour toute forme géométrique décrite à l'aide d'une famille de points ou d'hyperplans. Ainsi une courbe duale d'une courbe paramétrique plane est définie comme enveloppe d'une famille de droites. Ces courbes duales sont ensuite analysées pour trouver des relations de correspondances entre une courbe paramétrique et son image duale. En effet, des correspondances d'interpolation et de convexité sont établies et des exemples de courbes de Bézier duales sont illustrés. On fait ensuite une étude complète des correspondances de singularités entre courbes primales et duales. Enfin, une généralisation de la dualité géométrique à l'aide d'une matrice symétrique inversible a permis d'associer à une courbe paramétrique quelconque une famille de courbes duales dépendant de la matrice symétrique considérée.
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Lipková, Alica. "Návrh repliky letounu L-40 "Meta Sokol" - základní rozměry - technologie." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-227920.
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The object of the diploma thesis is a preparation of fundamentals for realization for replica of the aircraft L-40 „Meta Sokol“ matching the requirements of Certification Specification for Very Light Aeroplanes (CS-VLA). The preamble of the work deals with the changes made on the original aircraft necessary to satisfy the criterias of the above-mentioned specification. One of the main contents of the first part of the thesis is the definition of replica’s basic dimensions and preparation of aerostatic fundamentals, including longitudinal stability control. As next a suitable engine is chosen and calculation of corresponding performances is made. A detailed weight analysis and a determination of centre of gravity position (c.g. position), important for solving the stability of an airplane, is also presented. Finally, a brief description of the manufacturing process of individual components and also factors influencing the technology are discussed.
Books on the topic "Envelope curves"
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Giblin, P. J. Affine invariant distances, envelopes and symmetry sets. Hewlett-Packard Laboratories, Technical Publications Dept., 1996.
Find full textBook chapters on the topic "Envelope curves"
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Barrowclough, Oliver J. D., Bert Jüttler, and Tino Schulz. "Fast Approximate Implicitization of Envelope Curves Using Chebyshev Polynomials." In Latest Advances in Robot Kinematics. Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-4620-6_26.
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Bhowmick, Partha, Arindam Biswas, and Bhargab B. Bhattacharya. "PACE: Polygonal Approximation of Thick Digital Curves Using Cellular Envelope." In Computer Vision, Graphics and Image Processing. Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11949619_27.
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Amponsah, William, Francesco Marra, Lorenzo Marchi, Hélène Roux, Isabelle Braud, and Marco Borga. "Objective Analysis of Envelope Curves for Peak Floods of European and Mediterranean Flash Floods." In Climate Change Management. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-37425-9_14.
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Banks, Michael J., Elaine Cohen, and Timothy I. Mueller. "Chapter 7: An Envelope Approach to a Sketching Editor for Hierarchical Free-form Curve Design and Modification." In Knot Insertion and Deletion Algorithms for B-Spline Curves and Surfaces. Society for Industrial and Applied Mathematics, 1992. http://dx.doi.org/10.1137/1.9781611971583.ch7.
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Audin, Michèle. "Curves, Envelopes, Evolutes." In Geometry. Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-56127-6_8.
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Milardi, Martino, Evelyn Grillo, and Mariateresa Mandaglio. "The Importance of Testing Activities for a “New” Generation of Building Envelope." In The Urban Book Series. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-29515-7_63.
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AbstractThe construction sector is considered, directly or indirectly, one of the pillars for the application of technological solutions to rise the quality levels of building envelopes. The need to realize new processes capable of “dynamically” reading the responses of the built systems becomes an essential action to understand how the dynamics of climate change determine and trigger evident effects on the built environment. In this scenario, the contribution describes the experimental research activities on a curved facade—carried out at the TCLab Section of Building Future Lab of the Mediterranean University of Reggio Calabria—to verify its performance responses to extreme events according to specific standardized protocols. Therefore, this study focuses on the building envelope, as the main subsystem through which leakage occurs, not only in terms of thermal and dynamic fluxes, but of air and water permeability. Testing activities, nowadays of fundamental value for climate change phenomena, allow to predict the behavior of the built environment and at the same time to evaluate alternative solution. The research efforts go toward defining a design methodology for a new generation of building envelopes, capable of reacting to different contextual conditions by raising the environmental and performance quality according to adaptive dynamics. From the tests carried out, the results take the form of test protocols, giving real added value to research and implementing applied experimentation actions with highly reliable results.
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Wang, Yuxuan, Yuran Liu, Riley Studebaker, Billie Faircloth, and Robert Stuart-Smith. "Ceramic Incremental Forming–A Rapid Mold-Less Forming Method of Variable Surfaces." In Computational Design and Robotic Fabrication. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8637-6_43.
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AbstractFollowing architectural practice’s widespread adoption of 3D modelling software, the digital design of free-form surfaces has enabled more heterogeneously organized architectural assemblies. However, fabricating envelope components with double-curved surface geometry have remained a challenge, involving significant machine time and material waste, and great expense to produce. This proof-of-concept project proposes a rapid, low-cost, and minimal-waste approach to forming double curved ceramic components through a novel approach to Ceramic Incremental Forming (CIF), using a 6-axis industrial robot, a passive flexible mold, and a custom ball-rolling tool. The approach is comparable to Single Point Incremental Forming (SPIF) that is used for forming complex shapes with metal sheets. This method promises to achieve high-quality, ceramic building envelope components, while eliminating the need to build proprietary molds for each shape and reducing the waste in the forming process. Compared with other architectural mold-less forming methods such as clay 3D printing, the approach is more time and material efficient, while being able to achieve similar levels of complexity. Thus, CIF may offer potential for further development and industrial applications.
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Tiwari, Binod, and Beena Ajmera. "Advancements in Shear Strength Interpretation, Testing, and Use for Landslide Analysis." In Progress in Landslide Research and Technology. Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-44296-4_1.
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AbstractLandslides are devastating natural disasters that result in loss of life, property damage, and community disruption. They have global impacts, causing fatalities and economic losses, particularly in mountainous regions near densely populated areas. Landslides can be caused by natural factors, including water saturation from heavy rainfall, snowmelt, and changes in groundwater levels, as well as seismic activity such as earthquakes and volcanic eruptions. Human activities, such as altering drainage patterns, destabilizing slopes, and removing vegetation, also contribute to landslides. Construction and development on slopes, over-steepening, and improper land management practices can further increase the risk of landslides. A key component in understanding the stability of slopes will be knowledge of the shear strength of the soils involved. However, to do so, it will be necessary to understand the various measuring methods of shear strength, loading conditions, and other parameters. Different methods and tests are employed to determine the shear strength of soil, depending on the specific conditions and objectives. Direct shear tests are often utilized to measure peak and fully softened shear strengths. Triaxial tests, on the other hand, are suitable for assessing both peak and fully softened shear strengths under drained or undrained conditions. Generally, the ring shear device is preferred for measurements of the residual shear strengths. However, multiple reversal direct shear tests and specifically modified direct shear tests as well as triaxial tests have also been utilized for this purpose. The cyclic simple shear test is recommended as an effective technique for replicating in-situ conditions to investigate the cyclic resistance and post-cyclic shear strengths of soils. Several correlations have been developed in the literature to estimate various shear strengths, including the fully softened and residual shear strengths of soil, as summarized in this paper. These correlations utilize parameters such as the liquid limit, plasticity index, mineralogy, clay fraction, and effective normal stress. The undrained shear strength of over-consolidated soils can be captured with the use of the Stress History and Normalized Soil Engineering Properties (SHANSEP) method. Extending this approach with the use of the normalized undrained strength ratio can result in two correlations that can capture the undrained shear strength. The paper also presents correlations for the true and base friction angles to estimate the shear strength using Hvorslev’s theory. This allows for a departure from the use of the cohesion intercept and friction angle in the Mohr-Coulomb failure envelope, both of which are dependent on the over-consolidation ratio. The power function effectively represents the cyclic strength curves in soils with the curve fitting parameters a and b defining their shape and position. A correlation between the normalized undrained strength ratio and post-cyclic effective stress ratio to assess the undrained shear strength after cyclic loading was also introduced. This correlation was shown to also capture the effects of excess pore pressure dissipation and reductions in shear strength induced by a second cyclic load.
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Singh, David E., María J. Martín, and Francisco F. Rivera. "The Envelope of a Digital Curve Based on Dominant Points." In Discrete Geometry for Computer Imagery. Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/3-540-44438-6_37.
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Yang, Boyuan, Hui Zhang, Baokang Wu, et al. "Analysis of the Causes of Packer Failure in Production Operations Based on the Three-Dimensional Envelope Curve of the Packer." In Mechanisms and Machine Science. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-68775-4_50.
Full textConference papers on the topic "Envelope curves"
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Mitchell, Jonathan, Albert Brand, Matthew Hill, Nathan Wu, and Ajay Singh. "Bell 525 Airspeed Calibration Prior to First Flight." In Vertical Flight Society 72nd Annual Forum & Technology Display. The Vertical Flight Society, 2016. http://dx.doi.org/10.4050/f-0072-2016-11406.
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Bell Helicopter's 525 Relentless will be the world's first commercially certified fly-by-wire helicopter. As a fully computer controlled aircraft, the design aims at higher safety through reduced pilot workload, increased situational awareness, and improved handling qualities. The flight control system that achieves these results operates with numerous redundant sensors that provide flight data and feedback to the flight control logic. This paper describes the development of the Bell 525's redundant Pitot static airspeed system, showing how computational fluid dynamics (CFD) models were used to perform initial calibration of the triplex system far ahead of first flight. Since air data readings interact with the flight control logic, it was important to have a reasonable airspeed calibration available for first flight. The Bell 525 aerodynamics team developed an analytical approach to model the triplex airspeed system to account for position error across the flight envelope. The analysis developed calibration curves for forward flight, descent, and climbs to meet FAA rules for accuracy. The resulting process has allowed the 525 to conduct its first flight and full envelope expansion with an accurate and reliable production airspeed system.
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Scarpari, José, Donizeti Andrade, and João Otávio. "Autorotation: Building a Live Man's Curve." In Vertical Flight Society 71st Annual Forum & Technology Display. The Vertical Flight Society, 2015. http://dx.doi.org/10.4050/f-0071-2015-10287.
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Research has been carried at the Brazilian Air Commands' Flight Tests and Research Institute and Technological Institute of Aeronautics in order to theoretically analyze, conduct flight tests and propose both design improvements and new requirements for aeronautical regulations aiming the increase of safety during autorotation flight of lightweight, single-engine helicopters. This paper presents a methodology to obtain risk-level curves for each flight profile, analyzing and quantifying influential factors, in order to indicate technical and operational alternatives to reduce such risks. Different influential factors are analytically and numerically analyzed following a flight test campaign such as longitudinal attitude; lateral attitude; pilot reaction time; and workload for the pilot to perform a safe landing in autorotation. At the end of this phase of the study, results and methodology applied confirm that the information about performance and handling qualities of autorotation flight from aeronautical standards and flight manuals are non-conservative and can induce pilots to flight within an unsafe flight envelope. A risk-level curve, named iso-workload diagram, is presented as an alternative tool for the unawareness of these risk areas by operators.
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Čítek, David, Oto Melter, Ales Hvizdal, et al. "Experimental 3D printed concrete footbridge." In IABSE Symposium, Tokyo 2025: Environmentally Friendly Technologies and Structures: Focusing on Sustainable Approaches. International Association for Bridge and Structural Engineering (IABSE), 2025. https://doi.org/10.2749/tokyo.2025.2116.
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<p>The paper deals with the possibilities of using 3D printing for the construction of footbridges without reinforcement. Using the Solopisky footbridge as an example, the whole process is described—from the design, composition of the mixture, and printing process to the verification test and final assembly of the structure. The mixture used was developed by the Klokner Institute specifically for this implementation. It consists of individually selected components typical of fine-grained micro concrete and mortar to meet the requirements for mechanical properties, workability, pumpability of the fresh mix, and buildability of the printed material. For printing the structure, a continuous print route was designed using parabolic envelope curves that were parametrically filled with a circular pattern. After verifying the characteristics of the footbridge, it was installed at the pond near the village of Solopisky.</p>
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Wang, Yanli, and Ting-Leung Sham. "Fatigue and Creep-Fatigue Evaluation of Alloy 709 at 760 and 816°C." In AM-EPRI 2024. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.am-epri-2024p1161.
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Abstract A significant research and development effort is underway to support the qualification of Alloy 709 as a Class A construction material in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Division 5, High Temperature Reactors. This initiative includes a comprehensive Alloy 709 code qualification plan aimed at generating extensive material testing data crucial for compiling the code case data package. The data package is essential in establishing material-specific design parameters for Alloy 709 to be used as Section III, Division 5 Class A construction material for fast reactors, molten salt reactors and gas-cooled reactors. An ASME Section III, Division 5 material code case requires the evaluation of mechanical properties from a minimum of three commercial heats, covering anticipated compositional ranges. A key part of the data package involves fatigue and creep-fatigue testing at elevated temperatures, needed for developing the fatigue design curves and the damage envelope of the creep-fatigue interaction diagram (D-diagram). This paper summarizes the strain-controlled fatigue testing on three commercial heats of Alloy 709 at 760 and 816°C with strain ranges between 0.25% and 3%. The fatigue failure data are used to generate a preliminary fatigue design curve. Additionally, the creep-fatigue testing results at 816°C with tensile hold times of 10, 30, and 60 minutes are presented in support of developing the D-diagram for Alloy 709.
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Xue, Xia, Chenhui Luan, Pengcheng Wang, Yixuan Yang, Liang Ren, and Wenshuo Cai. "A dynamic envelope extraction method of spacecraft parameters based on improved curve matching search." In 2024 7th International Conference on Computer Information Science and Application Technology (CISAT). IEEE, 2024. http://dx.doi.org/10.1109/cisat62382.2024.10695424.
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Majewski, J., A. Wiktorowicz, and K. J. Opieliński. "A3 - Method of Determining the Envelope of the Blood Flow Velocity Curve inSpectral Doppler Ultrasound." In 20th Jubilee Winter Workshop on Acoustoelectronics. AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, 2024. https://doi.org/10.5162/20wwonae/a3.
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Brechner, Eric L. "General Tool Offset Curves and Surfaces." In ASME 1990 Design Technical Conferences. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/detc1990-0033.
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Abstract Offset curves and surfaces are often used to define two- and three-axis tool paths for circular and spherical cutting tools. This paper derives extensions of these curves and surfaces that can define tool paths for general cutting tool shapes. The general tool offsets are based on a study of mathematical envelopes of arbitrary smooth “structuring” surfaces centered on an arbitrary differentiable “foundation” surface. When a part is used for the foundation surface and a cutting tool is used for the structuring surface then the envelope forms a general tool offset. Explicit parameterizations are computed for these envelopes and for their tangents, normals, and curvature matrices in terms of the known respective quantities of the structuring and foundation surfaces.
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Ting, Kwun-Lon, and Cody Leeheng Chan. "Curvature Theory on Contact and Transfer Characteristics of Enveloping Curves." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-86378.
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In differential geometry, a curve is characterized by the curvature properties and so is a point trajectory in curvature theory. However, due to the rolling and sliding between contact curves, the characterization of enveloping curves embedded on rigid bodies in relative motion is not complete without the transfer (or shifting) characteristics of the contact point. This paper presents the new perspectives and the first comprehensive theory on not only the curvature characteristics but also the transfer characteristics between enveloping curves embedded on rigid bodies. The paper contains three parts. In the first part, a point traces a curve on the moving body and consequently traces a curve on the fixed body. Both generated curves form a pair of enveloping curves. This part establishes the foundation of the paper. Because each enveloping curve is treated as a point trajectory. One may examine all aspects of the enveloping process. Essentially this unmasks the veil that has hindered further understanding and observation of the enveloping behavior beyond the fundamental curvature. It represents a significant advancement on envelope theory. In the second part, the moving point is the instant center, which traces the moving centrode on the moving body and the fixed centrode on the fixed body. It characterizes the rolling between centrodes and the transfer characteristics of the instant center on each centrode. It not only offers a simple way to treat the instant center transfer (shifting) velocity but also successfully extends it to any order of motion. The third part is about the rolling and sliding of between enveloping curves embedded on rigid bodies in relative motion. It addresses the transfer characteristics of the contact on each of the contact curves for the first time. The transfer characteristics are functions of the rigid body motion characteristics. This part offers the vital kinematic aspect of enveloping curves distinctly different from the conventional curvature theory that addresses an individual curve. The proposed enveloping curvature theory offers an important model to account for all aspects of the contact and removes the veil that blurs the contact behavior caused by the traditional envelope definition of Fλxy=∂F∂λλxy=0. This is a kinematic solution for envelopes. The proposed theory is illustrated with an example of two rolling cylinders.
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Mlinar, John R., and Arthur G. Erdman. "Burmester Field Envelopes for Multiple Design Parameters." In ASME 1998 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/detc98/mech-5917.
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Abstract The Burmester field is the area swept by a Burmester curve as one or more of the design variables change. This paper presents the envelope of the Burmester field for more than one design parameter. It is shown that the envelope consists of various segments. These segments are found to be portions of Burmester curves and curves found using envelope theory. A two- and three-parameter example are provided and discussed. The application of the Burmester field concept to the design of linkages is also discussed. This includes the limitations on the selection of the second dyad.
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Du, Chaoliang, Yishou Wang, Jian Cai, and Xinlin Qing. "Quantitative monitoring of two-dimensional damage using envelope locating curves method." In SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, edited by Tribikram Kundu. SPIE, 2013. http://dx.doi.org/10.1117/12.2009580.
Full textReports on the topic "Envelope curves"
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Robbins, Bryant A., Johannes L. Wibowo, Kevin S. Holden, and Maureen K. Corcoran. Development of Envelope Curves for Predicting Void Dimensions from Overturned Trees. Defense Technical Information Center, 2014. http://dx.doi.org/10.21236/ada606867.
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McClain, M., A. Feldman, D. Kahaner, and X. T. Ying. An algorithm and computer program for the calculation of envelope curves. National Institute of Standards and Technology, 1989. http://dx.doi.org/10.6028/nist.ir.89-4210.
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