Bibliografias temáticas / High -dimensional ii chaos

Literatura científica selecionada sobre o tema "High -dimensional ii chaos"

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Publicado: 22 de julho de 2024

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Artigos de revistas sobre o assunto "High -dimensional ii chaos"

Chandrasekaran, Jeyamala, e S. J. Thiruvengadam. "Ensemble of Chaotic and Naive Approaches for Performance Enhancement in Video Encryption". Scientific World Journal 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/458272.

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Owing to the growth of high performance network technologies, multimedia applications over the Internet are increasing exponentially. Applications like video conferencing, video-on-demand, and pay-per-view depend upon encryption algorithms for providing confidentiality. Video communication is characterized by distinct features such as large volume, high redundancy between adjacent frames, video codec compliance, syntax compliance, and application specific requirements. Naive approaches for video encryption encrypt the entire video stream with conventional text based cryptographic algorithms. Although naive approaches are the most secure for video encryption, the computational cost associated with them is very high. This research work aims at enhancing the speed of naive approaches through chaos based S-box design. Chaotic equations are popularly known for randomness, extreme sensitivity to initial conditions, and ergodicity. The proposed methodology employs two-dimensional discrete Henon map for (i) generation of dynamic and key-dependent S-box that could be integrated with symmetric algorithms like Blowfish and Data Encryption Standard (DES) and (ii) generation of one-time keys for simple substitution ciphers. The proposed design is tested for randomness, nonlinearity, avalanche effect, bit independence criterion, and key sensitivity. Experimental results confirm that chaos based S-box design and key generation significantly reduce the computational cost of video encryption with no compromise in security.

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CONNELL, BENJAMIN S. H., e DICK K. P. YUE. "Flapping dynamics of a flag in a uniform stream". Journal of Fluid Mechanics 581 (22 de maio de 2007): 33–67. http://dx.doi.org/10.1017/s0022112007005307.

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We consider the flapping stability and response of a thin two-dimensional flag of high extensional rigidity and low bending rigidity. The three relevant non-dimensional parameters governing the problem are the structure-to-fluid mass ratio, μ = ρsh/(ρfL); the Reynolds number, Rey = VL/ν; and the non-dimensional bending rigidity, KB = EI/(ρfV2L3). The soft cloth of a flag is represented by very low bending rigidity and the subsequent dominance of flow-induced tension as the main structural restoring force. We first perform linear analysis to help understand the relevant mechanisms of the problem and guide the computational investigation. To study the nonlinear stability and response, we develop a fluid–structure direct simulation (FSDS) capability, coupling a direct numerical simulation of the Navier–Stokes equations to a solver for thin-membrane dynamics of arbitrarily large motion. With the flow grid fitted to the structural boundary, external forcing to the structure is calculated from the boundary fluid dynamics. Using a systematic series of FSDS runs, we pursue a detailed analysis of the response as a function of mass ratio for the case of very low bending rigidity (KB = 10−4) and relatively high Reynolds number (Rey = 103). We discover three distinct regimes of response as a function of mass ratio μ: (I) a small μ regime of fixed-point stability; (II) an intermediate μ regime of period-one limit-cycle flapping with amplitude increasing with increasing μ; and (III) a large μ regime of chaotic flapping. Parametric stability dependencies predicted by the linear analysis are confirmed by the nonlinear FSDS, and hysteresis in stability is explained with a nonlinear softening spring model. The chaotic flapping response shows up as a breaking of the limit cycle by inclusion of the 3/2 superharmonic. This occurs as the increased flapping amplitude yields a flapping Strouhal number (St = 2Af/V) in the neighbourhood of the natural vortex wake Strouhal number, St ≃ 0.2. The limit-cycle von Kármán vortex wake transitions in chaos to a wake with clusters of higher intensity vortices. For the largest mass ratios, strong vortex pairs are distributed away from the wake centreline during intermittent violent snapping events, characterized by rapid changes in tension and dynamic buckling.

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Zotos, Euaggelos E., e F. L. Dubeibe. "Orbital dynamics in the post-Newtonian planar circular restricted Sun–Jupiter system". International Journal of Modern Physics D 27, n.º 04 (março de 2018): 1850036. http://dx.doi.org/10.1142/s0218271818500360.

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The theory of the post-Newtonian (PN) planar circular restricted three-body problem is used for numerically investigating the orbital dynamics of a test particle (e.g. a comet, asteroid, meteor or spacecraft) in the planar Sun–Jupiter system with a scattering region around Jupiter. For determining the orbital properties of the test particle, we classify large sets of initial conditions of orbits for several values of the Jacobi constant in all possible Hill region configurations. The initial conditions are classified into three main categories: (i) bounded, (ii) escaping and (iii) collisional. Using the smaller alignment index (SALI) chaos indicator, we further classify bounded orbits into regular, sticky or chaotic. In order to get a spherical view of the dynamics of the system, the grids of the initial conditions of the orbits are defined on different types of two-dimensional planes. We locate the different types of basins and we also relate them with the corresponding spatial distributions of the escape and collision time. Our thorough analysis exposes the high complexity of the orbital dynamics and exhibits an appreciable difference between the final states of the orbits in the classical and PN approaches. Furthermore, our numerical results reveal a strong dependence of the properties of the considered basins with the Jacobi constant, along with a remarkable presence of fractal basin boundaries. Our outcomes are compared with the earlier ones regarding other planetary systems.

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Liu, Juan, Xiang Zhang, Jian Yang, Junhui Zhou, Yuan Yuan, Chao Jiang, Xiulian Chi e Luqi Huang. "Agarwood wound locations provide insight into the association between fungal diversity and volatile compounds in Aquilaria sinensis". Royal Society Open Science 6, n.º 7 (julho de 2019): 190211. http://dx.doi.org/10.1098/rsos.190211.

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The aim of the present study was to investigate the effect of wound location on the fungal communities and volatile distribution of agarwood in Aquilaria sinensis . Two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry revealed 60 compounds from the NIST library, including 25 sesquiterpenes, seven monoterpenes, two diterpenes, nine aromatics, nine alkanes and eight others. Of five agarwood types, Types IV and II contained the greatest number and concentration of sesquiterpenes, respectively. The fungal communities of the agarwood were dominated by the phylum Ascomycota and were significantly affected by the type of wound tissue. Community richness indices (observed species, Chao1, PD whole tree, ACE indices) indicated that Types I and IV harboured the most and least species-rich fungal communities, and the fungal communities of Types V, I, III and IV/II were dominated by Lasiodiplodia , Hydnellum , Phaeoisaria and Ophiocordyceps species, respectively. Correlations between fungal species and agarwood components revealed that the chemical properties of A. sinensis were associated with fungal diversity. More specifically, the dominant fungal genera of Types V, I and III ( Lasiodiplodia , Hydnellum and Phaeoisaria , respectively) were strongly correlated with specific terpenoid compounds. The finding that wound location affects the fungal communities and volatile distribution of agarwood provides insight into the formation of distinct agarwood types.

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Harrison, Mary Ann, e Ying-Cheng Lai. "Route to high-dimensional chaos". Physical Review E 59, n.º 4 (1 de abril de 1999): R3799—R3802. http://dx.doi.org/10.1103/physreve.59.r3799.

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HARRISON, MARY ANN, e YING-CHENG LAI. "BIFURCATION TO HIGH-DIMENSIONAL CHAOS". International Journal of Bifurcation and Chaos 10, n.º 06 (junho de 2000): 1471–83. http://dx.doi.org/10.1142/s0218127400000967.

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High-dimensional chaos has been an area of growing recent investigation. The questions of how dynamical systems become high-dimensionally chaotic with multiple positive Lyapunov exponents, and what the characteristic features associated with the transition are, remain less investigated. In this paper, we present one possible route to high-dimensional chaos. By this route, a subsystem becomes chaotic with one positive Lyapunov exponent via one of the known routes to low-dimensional chaos, after which the complementary subsystem becomes chaotic, leading to additional positive Lyapunov exponents for the whole system. A characteristic feature of this route is that the additional Lyapunov exponents pass through zero smoothly. As a consequence, the fractal dimension of the chaotic attractor changes continuously through the transition, in contrast to the transition to low-dimensional chaos at which the fractal dimension changes abruptly. We present a heuristic theory and numerical examples to illustrate this route to high-dimensional chaos.

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Saiki, Yoshitaka, Miguel A. F. Sanjuán e James A. Yorke. "Low-dimensional paradigms for high-dimensional hetero-chaos". Chaos: An Interdisciplinary Journal of Nonlinear Science 28, n.º 10 (outubro de 2018): 103110. http://dx.doi.org/10.1063/1.5045693.

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Auerbach, Ditza, Celso Grebogi, Edward Ott e James A. Yorke. "Controlling chaos in high dimensional systems". Physical Review Letters 69, n.º 24 (14 de dezembro de 1992): 3479–82. http://dx.doi.org/10.1103/physrevlett.69.3479.

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Blokhina, Elena V., Sergey P. Kuznetsov e Andrey G. Rozhnev. "High-Dimensional Chaos in a Gyrotron". IEEE Transactions on Electron Devices 54, n.º 2 (fevereiro de 2007): 188–93. http://dx.doi.org/10.1109/ted.2006.888757.

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MUSIELAK, Z. E., e D. E. MUSIELAK. "HIGH-DIMENSIONAL CHAOS IN DISSIPATIVE AND DRIVEN DYNAMICAL SYSTEMS". International Journal of Bifurcation and Chaos 19, n.º 09 (setembro de 2009): 2823–69. http://dx.doi.org/10.1142/s0218127409024517.

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Studies of nonlinear dynamical systems with many degrees of freedom show that the behavior of these systems is significantly different as compared with the behavior of systems with less than two degrees of freedom. These findings motivated us to carry out a survey of research focusing on the behavior of high-dimensional chaos, which include onset of chaos, routes to chaos and the persistence of chaos. This paper reports on various methods of generating and investigating nonlinear, dissipative and driven dynamical systems that exhibit high-dimensional chaos, and reviews recent results in this new field of research. We study high-dimensional Lorenz, Duffing, Rössler and Van der Pol oscillators, modified canonical Chua's circuits, and other dynamical systems and maps, and we formulate general rules of high-dimensional chaos. Basic techniques of chaos control and synchronization developed for high-dimensional dynamical systems are also reviewed.

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Mais fontes

Teses / dissertações sobre o assunto "High -dimensional ii chaos"

Yadav, Vaibhav. "Novel Computational Methods for Solving High-Dimensional Random Eigenvalue Problems". Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/4927.

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The primary objective of this study is to develop new computational methods for solving a general random eigenvalue problem (REP) commonly encountered in modeling and simulation of high-dimensional, complex dynamic systems. Four major research directions, all anchored in polynomial dimensional decomposition (PDD), have been defined to meet the objective. They involve: (1) a rigorous comparison of accuracy, efficiency, and convergence properties of the polynomial chaos expansion (PCE) and PDD methods; (2) development of two novel multiplicative PDD methods for addressing multiplicative structures in REPs; (3) development of a new hybrid PDD method to account for the combined effects of the multiplicative and additive structures in REPs; and (4) development of adaptive and sparse algorithms in conjunction with the PDD methods. The major findings are as follows. First, a rigorous comparison of the PCE and PDD methods indicates that the infinite series from the two expansions are equivalent but their truncations endow contrasting dimensional structures, creating significant difference between the two approximations. When the cooperative effects of input variables on an eigenvalue attenuate rapidly or vanish altogether, the PDD approximation commits smaller error than does the PCE approximation for identical expansion orders. Numerical analysis reveal higher convergence rates and significantly higher efficiency of the PDD approximation than the PCE approximation. Second, two novel multiplicative PDD methods, factorized PDD and logarithmic PDD, were developed to exploit the hidden multiplicative structure of an REP, if it exists. Since a multiplicative PDD recycles the same component functions of the additive PDD, no additional cost is incurred. Numerical results show that indeed both the multiplicative PDD methods are capable of effectively utilizing the multiplicative structure of a random response. Third, a new hybrid PDD method was constructed for uncertainty quantification of high-dimensional complex systems. The method is based on a linear combination of an additive and a multiplicative PDD approximation. Numerical results indicate that the univariate hybrid PDD method, which is slightly more expensive than the univariate additive or multiplicative PDD approximations, yields more accurate stochastic solutions than the latter two methods. Last, two novel adaptive-sparse PDD methods were developed that entail global sensitivity analysis for defining the relevant pruning criteria. Compared with the past developments, the adaptive-sparse PDD methods do not require its truncation parameter(s) to be assigned a priori or arbitrarily. Numerical results reveal that an adaptive-sparse PDD method achieves a desired level of accuracy with considerably fewer coefficients compared with existing PDD approximations.

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Munoz, Sardaneta Maria Minerva. "Two-dimensional ionised gas kinematics in edge-on late-type galaxies in low and high density environments". Thesis, Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0527.

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Certaines galaxies spirales ont une composante de gaz chaud affichant une structure épaisse, le DIG. Les couches de DIG détectées à plusieurs kpc hors du plan galactique (eDIG) ont des propriétés cinématiques différentes de celles du gaz ionisé dans le disque. Dans les galaxies vues par la tranche, l'eDIG peut être étudiée sans confusion avec le gaz dans le disque. Une propriété essentielle qui régit l’existence d’eDIG est l’activité de formation stellaire (SFR), mais il reste incertain quelle est la source principale d'ionisation des eDIG. L'interférométrie Fabry-Perot (FP) offre une couverture bidimensionnelle pour détecter l'émission Hα diffuse à haute résolution spectrale. Dans ce travail, les données FP de deux échantillons de galaxies de type tardif vues par la tranche ont été étudiées pour comprendre la prévalence et la cinématique de l'eDIG. Des images auxiliaires dans le proche infrarouge ont aussi été utilisées. Un échantillon a été extrait du catalogue "Herschel Reference Survey (HRS)" où ont été détectés des caractéristiques de galaxies en interaction avec le milieu intergalactique. L'évolution des galaxies étant influencée par l'environnement, un autre échantillon a été sélectionné parmi le "Catalogue of Isolated Galaxies (CIG)". Les résultats préliminaires montrent que, dans les galaxies isolées, le décalage de rotation augmente avec la SFR. La galaxie spirale de l’amas de la Vierge, NGC 4330, est sujet à des transformations majeures dues à la densité de son environnement. Étant représentative de l'échantillon HRS, une analyse cinématique Hα détaillée de NGC 4330 a été réalisée, trouvant des similarités cinématiques avec son gaz atomique et moléculaire
Some spiral galaxies have a hot gas component displaying a thick disk, the diffuse ionised gas (DIG). DIG layers detected several kpc out of the galactic plane, called extra-planar DIG (eDIG), have different kinematic properties than the ionised gas in the disk. In edge-on galaxies, the longitudinal and vertical gas kinematics can be studed without confusion with the disk gas. A key property governing the presence of the eDIG is the star-forming activity (SFR), but it is still unclear which is the major source of the eDIG ionisation. Fabry-Perot interferometry offers two-dimensional coverage to detect diffuse Hα emission with high spectral resolution. In this work, we studied Hα data acquired using this technique for two samples of late-type galaxies viewed edge-on (i≥75deg) in order to understand the prominence and kinematics of the eDIG. To discriminate between in-disk gas emission from out-of-disk gas emission seen in projection, we used near-infrared imagery. A sample of 43 galaxies was extracted from the ‘Herschel Reference Survey (HRS)’ catalogue on which we detected features of galaxies interacting with the ICM. As the galaxy evolution can be perturbed by the environment, a sample of 14 galaxies was selected from the "Catalogue of Isolated Galaxies (CIG)". Preliminary results show that in isolated galaxies the rotational lag increases with their intrinsic SFR. The large Virgo spiral galaxy, NGC 4330, is undergoing major transformations due to the density of its environment. Being representative of the HRS sample, a deep Hα kinematic analysis of it was performed finding kinematic similarities with its atomic and molecular gas

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Uffner, Neil E. "THREE-DIMENSIONAL ASSESSMENT OF THE EFFECTS OF EXTRACTION ON THE SMILE IN CLASS II HIGH AND LOW MANDIBULAR PLANE ANGLE PATIENTS". Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/219332.

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Oral Biology
M.S.
The annals of orthodontics are filled with studies aimed to understand how extraction orthodontic treatment might change the face. Although many studies have addressed profile changes due to extraction treatment, fewer studies have focused on how extractions change a patients smile. With the advent of surface imaging systems such as 3dMD, it is now possible to visualize the smile, and any changes incurred during orthodontic treatment, in three dimensions. Subjects for this study were chosen from the pool of 11-18 year old patients treated at the Podray Orthodontic Clinic at the Temple University Kornberg School of Dentistry. Subjects were Cl II patients, and must have been treated with either extraction of any combination of premolars or treated without extraction. Subjects were divided into four experimental groups based on two characteristics- mandibular angle (those with angles greater than 28o versus those with angles less than 28o) and treatment (extraction versus non-extraction). The resulting groups were separated as follows: high-angle extraction patients (n=8), low-angle extraction patients (n=6), high-angle non-extraction patients (n=7), and low-angle non-extraction patients (n=15). For each subject initial and final 3dMD images were superimposed using 3dMD Vultus software. A color histogram was constructed to visualize changes during treatment. The cheeks, commissures, upper and lower lips, chin, and nose, were also landmarked, and the changes in these landmarks were calculated. Volume changes were also calculated between pre and post treatment 3D data. Results showed that the lower lip and right commissure changes between high-angle extraction and non-extraction groups were statistically significant. A qualitative analysis of the histograms further supported these findings. In general, a greater change in soft tissue landmarks and soft tissue volumes could be seen in high-angle patients than low-angle patients. Differences in the changes that result from treatment type (extraction vs. non-extraction) were seen in the high-angle group. In contrast, similar changes result from treatment type (extraction vs. non-extraction) in the low-angle groups. Furthermore, the lip changes seen in extraction patients upon smiling are very similar to those changes seen in the same patient in repose. Most interestingly, soft tissue differences of the face due to treatment, growth, or both, seem to disappear upon smiling, with the exception of the lips. Qualitative assessment of these changes in the smile might be a more appropriate method for identifying soft tissue changes than statistical analyses. Similar studies with larger sample sizes are a promising direction for future research.
Temple University--Theses

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Papasikos, Jacy. "THREE-DIMENSIONAL EVALUATION OF SOFT-TISSUE CHANGES IN EXTRACTION AND NON-EXTRACTION TREATMENT OF CLASS II HIGH AND LOW MANDIBULAR PLANE ANGLE ORTHODONTIC PATIENTS". Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/225655.

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Oral Biology
M.S.
Facial esthetics affect an individual's quality of life, self-image, social behavior, and public perception. The oro-facial region, in particular, plays a pivotal role in facial esthetics as dento-facial deformities can cause an individual to be perceived as less attractive, less successful, and less socially acceptable. The ability of orthodontic treatment to alter the soft-tissue facial form makes it a powerful tool to improve facial esthetics. Orthodontic treatment exhibits the most control over the soft-tissue in the lower third of the face, specifically the profile, position of the lips, and lower-third convexity. The position of the soft-tissue in this region plays an important role in the perception of facial attractiveness. Due to the importance of the oro-facial region in facial esthetics, it is of the utmost importance that orthodontists better understand the effects of their treatment on the soft-tissue. The majority of literature evaluates soft tissue changes using 2-D imaging, such as a profile photo or lateral cephalogram; however, the evaluation of soft-tissue changes requires more than just what is seen in a 2-D sagittal image. It is essential that this knowledge is obtained in the most accurate and realistic way possible; to understand changes in three-dimensions instead of two. Using 3dMD technology, pre- and post- three-dimensional soft tissue images of dental Class II patients with high or low mandibular plane angle, treated with or without extraction therapy, were compared. The objective was to determine the effect of extraction treatment on the soft-tissue of different facial types. Subjects were sampled from a database of patients treated by orthodontic residents under the supervision of faculty at the graduate orthodontic clinic of the Maurice H. Kornberg School of Dentistry at Temple University in Philadelphia, PA. Pre- and post-treatment 3dMD images were obtained of 42 dental Class II, high-angle (FMA ≥ 28) and low-angle (FMA < 28) subjects treated with extraction or non-extraction therapy. The 3dMDface system (3dMD, Atlanta, GA) is a stereophotogrammetric system used to capture 3D soft tissue images. Pre- and post-treatment images were superimposed to evaluate soft-tissue changes both quantitatively and qualitatively. Quantitative Analysis: The average linear (mm) changes between the pre- and post-images for each group were recorded for the following areas: right/left commissures and cheeks, upper/lower lips at the midline, chin (pogonion), and tip of the nose. In addition, sectional volumetric (cc) changes of the peri-oral area were recorded. The mean volumetric and linear changes were compared between groups. Qualitative Analysis: Color histograms were created from the superimpositions, representing a color-coded map of the direction and magnitude of soft-tissue changes. The magnitude and direction correspond to color, with warmer colors, such as pink and purple, representing positive changes in the soft-tissue (anterior movement) and cooler colors, like green, indicating a negative change (posterior movement). To allow comparison, the degree of change was coded using symbols, ranging from (+++) to (0) to (---), which correspond to the colors observed in each histogram. Coding was performed for the following areas: upper/lower lip, right/left commissures, right/left cheek, tip of the nose and chin (Horizontal (AP) and Vertical movement), the naso-labial fold, and the mento-labial fold. The coding for each facial area was placed in a table and color coded to aid visual analysis. The color-coded tables were analyzed for patterns within and between groups. While the quantitative analysis found no statistically significant linear and volumetric differences between each group, the qualitative analysis of the 3-D histograms revealed noticeable changes in the soft-tissue. Similar changes resulting from treatment type (extraction vs. non-extraction) were seen in both the high and low angle groups. The changes exhibited by the upper lip were independent of treatment and facial type: retraction was seen in all groups, likely due to Class II mechanics. In contrast, the changes exhibited by the lower lip, nasolabial fold, and mentolabial fold were more dependent on treatment type, becoming fuller in the non-extraction groups, while exhibiting more negative changes in the extraction groups. The commissures and cheeks exhibited unpredictable changes regardless of treatment and facial type. The nose and chin exhibited similar changes in all groups. These data suggest that orthodontic treatment may in fact induce predictable qualitative responses from specific areas of the soft-tissue face. We also conclude that qualitative assessment of soft-tissue facial change is more appropriate than quantitative assessment.
Temple University--Theses

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Teng, Sin Yong. "Intelligent Energy-Savings and Process Improvement Strategies in Energy-Intensive Industries". Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-433427.

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S tím, jak se neustále vyvíjejí nové technologie pro energeticky náročná průmyslová odvětví, stávající zařízení postupně zaostávají v efektivitě a produktivitě. Tvrdá konkurence na trhu a legislativa v oblasti životního prostředí nutí tato tradiční zařízení k ukončení provozu a k odstavení. Zlepšování procesu a projekty modernizace jsou zásadní v udržování provozních výkonů těchto zařízení. Současné přístupy pro zlepšování procesů jsou hlavně: integrace procesů, optimalizace procesů a intenzifikace procesů. Obecně se v těchto oblastech využívá matematické optimalizace, zkušeností řešitele a provozní heuristiky. Tyto přístupy slouží jako základ pro zlepšování procesů. Avšak, jejich výkon lze dále zlepšit pomocí moderní výpočtové inteligence. Účelem této práce je tudíž aplikace pokročilých technik umělé inteligence a strojového učení za účelem zlepšování procesů v energeticky náročných průmyslových procesech. V této práci je využit přístup, který řeší tento problém simulací průmyslových systémů a přispívá následujícím: (i)Aplikace techniky strojového učení, která zahrnuje jednorázové učení a neuro-evoluci pro modelování a optimalizaci jednotlivých jednotek na základě dat. (ii) Aplikace redukce dimenze (např. Analýza hlavních komponent, autoendkodér) pro vícekriteriální optimalizaci procesu s více jednotkami. (iii) Návrh nového nástroje pro analýzu problematických částí systému za účelem jejich odstranění (bottleneck tree analysis – BOTA). Bylo také navrženo rozšíření nástroje, které umožňuje řešit vícerozměrné problémy pomocí přístupu založeného na datech. (iv) Prokázání účinnosti simulací Monte-Carlo, neuronové sítě a rozhodovacích stromů pro rozhodování při integraci nové technologie procesu do stávajících procesů. (v) Porovnání techniky HTM (Hierarchical Temporal Memory) a duální optimalizace s několika prediktivními nástroji pro podporu managementu provozu v reálném čase. (vi) Implementace umělé neuronové sítě v rámci rozhraní pro konvenční procesní graf (P-graf). (vii) Zdůraznění budoucnosti umělé inteligence a procesního inženýrství v biosystémech prostřednictvím komerčně založeného paradigmatu multi-omics.

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Rom-Kedar, Vered. "Part I. An analytical study of transport, mixing and chaos in an unsteady vortical flow. Part II. Transport in two dimensional maps". Thesis, 1989. https://thesis.library.caltech.edu/963/1/Rom-kedar_v_1989.pdf.

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PART I: We examine the transport properties of a particular two dimensional, inviscid incompressible flow using dynamical systems techniques. The velocity field is time periodic and consists of the velocity field induced by a vortex pair plus an oscillating strain-rate field. In the absence of the strain-rate field the vortex pair moves with a constant velocity and carries with it a constant body of fluid. When the strain-rate field is added the picture changes dramatically; fluid is entrained and detrained from the neighborhood of the vortices and chaotic particle motion occurs. We investigate the mechanism for this phenomena and study the transport and mixing of fluid in this flow. Our work consists of both numerical and analytical studies. The analytical study includes the interpretation of the invariant manifolds as the underlying structure which govern the transport. Then we use Melnikov's technique to investigate the behavior of the manifolds as the parameters of the problem change and to prove the existence of a horseshoe map and thus the existence of chaotic particle paths in the flows. Using the Melnikov technique once more we develop an analytical estimate of the flux rate into and out of the vortex neighborhood. We develop a technique for determining the residence time distribution for fluid particles near the vortices. The technique involves an understanding of the geometry of the tangling of the stable and unstable manifolds and results in a dramatic reduction in computational effort for the residence time distributions. Additionally, we develop a finite time analog of the Liapunov exponent which measures the effect of, the horseshoes on trajectories passing through the mixing region. The numerical work verifies the analytical predictions regarding the structure of the invariant manifolds, the mechanism for entrainment and detrainment, and the flux rate. PART II: We study transport in the two dimensional phase space of Cr diffeomorphisms (r >= 1) of two manifolds between regions of the phase space bounded by pieces of the stable and unstable manifolds of hyperbolic fixed points. The mechanism for the transport is associated with the dynamics of homoclinic and heteroclinic tangles and the study of this dynamics leads to a general formulation for the transport rates in terms of distributions of small regions in phase space ("lobes"). It is shown how the method applies to three geometrical configurations, one of which corresponds to the geometry associated with the Kelvin-Stuart Cat's eye flow undergoing a time periodic perturbation. In this case the formulae imply, for example, that the evolution of only two lobes determines the mass transport from the upper to the lower half plane of the fluid flow. As opposed to previous studies this formulation takes into account the effect of re-entrainment of the lobes, i.e. the implications of the lobes leaving and re-entering the specified regions on the transport rates. The formulation is developed for both area preserving and non area preserving two dimensional diffeomorphisms and does not require the map to be near integrable. The techniques involved in applying this formulation are discussed including the possible use of the generating function for computing the distributions of the lobes in phase space, and the use of Poincare maps which enables one to study the transport in continuous time systems via the above formalism. In particular, we demonstrate how the right choice of the Poincare section can reduce the calculations of the transport rates.

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Livros sobre o assunto "High -dimensional ii chaos"

Giné, Evarist, David M. Mason e Jon A. Wellner, eds. High Dimensional Probability II. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1.

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Gine, Evarist, e David M. Mason. High dimensional probability II. Editado por Wellnerr Jon A. 1945- e e.-libro Corp. New York: Springer Science+Business Media, 2000.

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Awrejcewicz, J. Smooth and nonsmooth high dimensional chaos and the Melnikov-type methods. Singapore: World Scientific, 2007.

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NATO Advanced Research Workshop on Frontiers of High-Pressure Research (2nd 2001 Pingree Park, Colo.). Frontiers of high pressure research II: Application of high pressure to low-dimensional novel electronic materials. Dordrecht: Kluwer Academic Publishers, 2001.

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Hochheimer, Hans D., Bogdan Kuchta, Peter K. Dorhout e Jeffery L. Yarger, eds. Frontiers of High Pressure Research II: Application of High Pressure to Low-Dimensional Novel Electronic Materials. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0520-3.

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NATO Advanced Research Workshop on Frontiers of High Pressure Research (2nd 2001 Pingree Park, Colo.). Frontiers of high pressure research II: Application of high pressure to low-dimensional novel electronic materials. Dordrecht: Kluwer Academic Publishers, 2001.

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Burke, Roger. Duct flow nonuniformities: Effects of struts in SSME HGM IIp+s : final report. Huntsville, AL: Lockheed Missiles & Space Co., Huntsville Engineering Center, 1988.

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A, Delaney Robert, Bettner James L e United States. National Aeronautics and Space Administration., eds. Investigation of advanced counterrotation blade configuration concepts for high speed turboprop systems: Task II, unsteady ducted propfan analysis. [Washington, D.C.]: National Aeronautics and Space Administration, 1991.

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Québec) International Workshop on Perspectives on High-Dimensional Data Analysis (2nd 2012 Montréal. Perspectives on big data analysis: Methodologies and applications : International Workshop on Perspectives on High-Dimensional Data Anlaysis II, May 30-June 1, 2012, Centre de Recherches Mathématiques, University de Montréal, Montréal, Québec, Canada. Editado por Ahmed, S. E. (Syed Ejaz), 1957- editor of compilation. Providence, Rhode Island: American Mathematical Society, 2014.

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(Editor), Evarist Gine, David M. Mason (Editor) e Jon A. Wellner (Editor), eds. High Dimensional Probability II (Progress in Probability). Birkhäuser Boston, 2001.

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Capítulos de livros sobre o assunto "High -dimensional ii chaos"

Asaad, Serwan. "High-Dimensional Spins". In Electrical Control and Quantum Chaos with a High-Spin Nucleus in Silicon, 9–24. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-83473-9_2.

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Marcus, Michael B. "A Sufficient Condition for the Continuity of High Order Gaussian Chaos Processes". In High Dimensional Probability, 263–76. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8829-5_16.

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Frühauf, C., S. Hartmann, B. Seifert e C. Uhl. "Determinism Testing of Low-Dimensional Signals Embedded in High-Dimensional Multivariate Time Series". In Chaos and Complex Systems, 3–14. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-35441-1_1.

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de la Peña, Victor H., Michael J. Klass e Tze Leung Lai. "Moment Bounds for Self-Normalized Martingales". In High Dimensional Probability II, 3–11. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_1.

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Fernique, X. "Continuité de certaines fonctions aléatoires gaussiennes à valeurs dans l p , 1 ≤ p < ∞". In High Dimensional Probability II, 137–61. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_10.

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Li, Wenbo V., e Qi-Man Shao. "A Note on the Gaussian Correlation Conjecture". In High Dimensional Probability II, 163–71. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_11.

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Marcus, Michael B. "Probability Estimates for Lower Levels of Certain Gaussian Processes with Stationary Increments". In High Dimensional Probability II, 173–79. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_12.

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Deheuvels, Paul, Uwe Einmahl e David M. Mason. "Asymptotic Independence of the Local Empirical Process Indexed by Functions". In High Dimensional Probability II, 183–205. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_13.

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Peskir, Goran. "The Azéma-Yor Embedding in Brownian Motion with Drift". In High Dimensional Probability II, 207–21. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_14.

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Sakhanenko, Alexander I. "A New Way to Obtain Estimates in the Invariance Principle". In High Dimensional Probability II, 223–45. Boston, MA: Birkhäuser Boston, 2000. http://dx.doi.org/10.1007/978-1-4612-1358-1_15.

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Trabalhos de conferências sobre o assunto "High -dimensional ii chaos"

Amabili, M. "Large-Amplitude Vibrations of Thin Panels". In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14616.

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Geometrically nonlinear vibrations of circular cylindrical panels with different boundary conditions and subjected to harmonic excitation are numerically investigated. The Donnell's nonlinear strain-displacement relationships are used to describe geometric nonlinearity; in-plane inertia is taken into account. Different boundary conditions are studied and the results are compared; for all of them zero normal displacements at the edges are assumed. In particular, three models are considered in order to investigate the effect of different boundary conditions: Model A for free in-plane displacement orthogonal to the edges, elastic distributed springs tangential to the edges and free rotation; Model B for classical simply supported edges; Model C for fixed edges and distributed rotational springs at the edges. Clamped edges are obtained with the Model C for very high value of the stiffness of rotational springs. The nonlinear equations of motion are obtained by the Lagrange multi-mode approach, and are studied by using the code AUTO based on pseudo-arclength continuation method. Convergence of the solution with the number of generalized coordinates is numerically verified. Complex nonlinear dynamics is also investigated by using bifurcation diagrams from direct time integration and calculation of the Lyapunov exponents and the Lyapunov dimension. Interesting phenomena such as (i) subharmonic response, (ii) period doubling bifurcations, (iii) chaotic behavior and (iv) hyper-chaos with four positive Lyapunov exponents have been observed.

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QIU, Wan chun, e Shan jun YAN. "An image encryption algorithm based on the combination of low - dimensional chaos and high - dimensional chaos". In 2019 3rd International Conference on Electronic Information Technology and Computer Engineering (EITCE). IEEE, 2019. http://dx.doi.org/10.1109/eitce47263.2019.9094882.

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Iyengar, Nikhil, e Dimitri N. Mavris. "High-Dimensional Uncertainty Propagation in Aerodynamics using Polynomial Chaos-Kriging". In AIAA AVIATION 2023 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2023. http://dx.doi.org/10.2514/6.2023-3766.

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Wu, Jiachen, Liangcai Cao e Guofan Jin. "High-quality texture reconstruction for three-dimensional multi-view imaging (Conference Presentation)". In Ultra-High-Definition Imaging Systems II, editado por Toyohiko Yatagai, Yasuhiro Koike e Seizo Miyata. SPIE, 2019. http://dx.doi.org/10.1117/12.2509615.

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HU, GANG, MENG ZHAN e YING ZHANG. "TRANSITION FROM HIGH-DIMENSIONAL CHAOS TO PERIODICITY BY WEAK MUTUAL RESONANT INTERACTIONS". In Proceedings of the Third Joint Meeting of Chinese Physicists Worldwide. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812776785_0047.

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Ferretti, G., S. G. Rajeev e Z. Yang. "Three dimensional quantum chromodynamics". In Proceedings of the XXVI International Conference on High Energy Physics. Vol. II. AIP, 1992. http://dx.doi.org/10.1063/1.43442.

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Meteyer, Erwan, Pascal Picart e Charles Pézerat. "Transient force identification by use of high-speed digital holography". In Optics and Photonics for Advanced Dimensional Metrology II, editado por Peter J. de Groot, Richard K. Leach e Pascal Picart. SPIE, 2022. http://dx.doi.org/10.1117/12.2624155.

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Ahmad, Musheer, e Shahzad Alam. "A Novel Approach for Efficient S-Box Design Using Multiple High-Dimensional Chaos". In 2014 Fourth International Conference on Advanced Computing & Communication Technologies (ACCT). IEEE, 2014. http://dx.doi.org/10.1109/acct.2014.14.

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Geiyer, Daniel, e Jeffrey L. Kauffman. "High-Dimensional Chaos Control Algorithms for Improved Piezoelectric Energy Harvesting Using a Bistable Structure". In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46654.

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Linear cantilevered piezoelectric energy harvesters typically rely on excitation around a resonance frequency for peak operation. Compounding the problem, typical ambient environments either vary dynamically in time or possess energy distributed across a wide spectrum of frequencies. Nonlinear broadband techniques have been implemented with success, but rely on chance that steady-state high energy orbits result as opposed to the low energy or chaotic trajectories that coexist in the basin of attraction. This work aims to implement two high dimensional chaotic controllers for large period orbits located within the chaotic attractor. The first control law is defined using traditional OGY, while the second uses the principles of invariant manifolds and is therefore independent of the system Jacobian. Comparison of the two control methods aims to show that invariant principles are less computationally intensive and result in equivalent stabilized orbits. Furthermore, the only necessary measurement for control design is a single time series representing a state of the system. This article compares two methods of chaos control and their ability to stabilize a large period orbit within the chaotic attractor for improved broadband piezoelectric energy harvesting.

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Kanti, Panagiota. "What can we learn from a Higher-Dimensional Decaying Black Hole?" In CAIRO INTERNATIONAL CONFERENCE ON HIGH ENERGY PHYSICS (CICHEP II). AIP, 2007. http://dx.doi.org/10.1063/1.2435277.

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Relatórios de organizações sobre o assunto "High -dimensional ii chaos"

Mirus, K. A., e J. C. Sprott. Controlling chaos in a high dimensional system with periodic parametric perturbations. Office of Scientific and Technical Information (OSTI), outubro de 1998. http://dx.doi.org/10.2172/291145.

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Mirus, K. A., e J. C. Sprott. Controlling chaos in low and high dimensional systems with periodic parametric perturbations. Office of Scientific and Technical Information (OSTI), junho de 1998. http://dx.doi.org/10.2172/663249.

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Kamath, C., e J. Franzman. Spatio-Temporal Surrogates for Interaction of a Jet with High Explosives: Part II - Clustering Extremely High-Dimensional Grid-Based Data. Office of Scientific and Technical Information (OSTI), junho de 2023. http://dx.doi.org/10.2172/1984764.

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Balbas, Jorge, e Eitan Tadmor. Non-Oscillatory Central Schemes for One- and Two-Dimensional MHD Equations. II: High-Order Semi-Discrete Schemes. Fort Belvoir, VA: Defense Technical Information Center, junho de 2004. http://dx.doi.org/10.21236/ada448180.

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Weeks, Timothy "Dash". DTPH56-13-X-000013 Modern High-Toughness Steels for Fracture Propagation and Arrest Assessment-Phase II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), setembro de 2018. http://dx.doi.org/10.55274/r0012037.

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NIST work developed processes to identify the stress/strain/crack velocity conditions for unstable high-rate ductile crack propagation found in a full-scale pipeline burst test and duplicate those conditions in a medium-scale test. With modeling to validate conditions and assumptions used in reducing the scale of the tests. A medium-scale test to elucidate material property data necessary to qualify high-strength high-toughness steels based on the correlation to large-scale tests. Parametric determination of the material properties governing fracture propagation or arrest-ability was developed. This will assist researchers to determine a relevant and effective small-scale test (or tests) that provides enough information for material selection, design, reliability, as well as integrity and risk assessment. Pipe evaluated includes API5L X70 and X80 pipe. The strain was measured by a three-dimensional digital image correlation system. This project takes a phased approach with complementary research in successive phases beginning with a road map to systematically fill gaps in knowledge and understanding of the problem of unstable high-rate ductile running failures in pipelines. This report is structured to highlight the problem statement with respect to the current state of the art understanding, define knowledge gaps and present the plan, and progress toward meeting the objective. The following sections specifically cover the effort to develop and inform a constitutive material model necessary for the structural model of the medium-scale test. The material testing required to inform the constitutive material model is presented. Conclusions of this phase of the project are also presented in addition to the proposed work in Phase III of the project.

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Psuty, Norbert, Tanya Silveira, Andrea Habeck, Dennis Skidds, Sara Stevens, Katy Ames e Glenn Liu. Northeast Coastal and Barrier Network geomorphological monitoring protocol: Part II ? coastal topography, version 2. National Park Service, 2024. http://dx.doi.org/10.36967/2301966.

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Coastal topography was ranked as one of the most important variables for monitoring following a review of potential vital signs in the coastal parks of the Northeast Coastal and Barrier Network (NCBN). Changes in coastal topography, whether caused by erosion or accretion, vary both spatially and temporally. Understanding these variations is key to early recognition of potential problems affecting natural and cultural resources in coastal parks. For managers, understanding spatial and temporal patterns of geomorphologic change is basic to optimal management of any coastal park because the interface of marine and land systems 1) is highly dynamic and driven by multiple forcing mechanisms, 2) results in alterations to resource patterns and dynamics at habitat and ecosystem levels, and 3) can eventually result in the loss of static resources. The establishment of local, long-term monitoring programs help us to understand the processes that are driving coastal change of beaches, dunes, and bluffs within the parks. This Coastal Topography Monitoring Protocol has been developed for use in the Northeast Coastal and Barrier Network parks. Monitoring is accomplished with survey-grade Global Positioning System (GPS)/Global Navigation Satellite Systems (GNSS) equipment that collects topographic data along pre-established transects spaced at regular intervals, augmented by more intense data-collection in areas of special concern to the parks. A network of high-quality survey control monuments (often referred to as benchmarks), used as accuracy assessment reference is located within each of the NCBN parks, providing a robust basis for long-term monitoring. Spring and/or fall surveys conducted in accordance with standard operating procedures generate coastal topography datasets that are organized and assembled by the NCBN data manager into a database for analysis and archival purposes. Dimensional parameters are measured to describe the beach-dune-bluff system, and attributes are compared and analyzed in a cross-shore and alongshore perspective, providing information about the temporal and spatial changes on beach-dune-bluff morphologies in the parks. The overall goal is to create a replicable means of data gathering that is efficient, adheres to scientific principles, and meets the management needs of the coastal parks.

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Warrick, Arthur W., Gideon Oron, Mary M. Poulton, Rony Wallach e Alex Furman. Multi-Dimensional Infiltration and Distribution of Water of Different Qualities and Solutes Related Through Artificial Neural Networks. United States Department of Agriculture, janeiro de 2009. http://dx.doi.org/10.32747/2009.7695865.bard.

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The project exploits the use of Artificial Neural Networks (ANN) to describe infiltration, water, and solute distribution in the soil during irrigation. It provides a method of simulating water and solute movement in the subsurface which, in principle, is different and has some advantages over the more common approach of numerical modeling of flow and transport equations. The five objectives were (i) Numerically develop a database for the prediction of water and solute distribution for irrigation; (ii) Develop predictive models using ANN; (iii) Develop an experimental (laboratory) database of water distribution with time; within a transparent flow cell by high resolution CCD video camera; (iv) Conduct field studies to provide basic data for developing and testing the ANN; and (v) Investigate the inclusion of water quality [salinity and organic matter (OM)] in an ANN model used for predicting infiltration and subsurface water distribution. A major accomplishment was the successful use of Moment Analysis (MA) to characterize “plumes of water” applied by various types of irrigation (including drip and gravity sources). The general idea is to describe the subsurface water patterns statistically in terms of only a few (often 3) parameters which can then be predicted by the ANN. It was shown that ellipses (in two dimensions) or ellipsoids (in three dimensions) can be depicted about the center of the plume. Any fraction of water added can be related to a ‘‘probability’’ curve relating the size of the ellipse (or ellipsoid) that contains that amount of water. The initial test of an ANN to predict the moments (and hence the water plume) was with numerically generated data for infiltration from surface and subsurface drip line and point sources in three contrasting soils. The underlying dataset consisted of 1,684,500 vectors (5 soils×5 discharge rates×3 initial conditions×1,123 nodes×20 print times) where each vector had eleven elements consisting of initial water content, hydraulic properties of the soil, flow rate, time and space coordinates. The output is an estimate of subsurface water distribution for essentially any soil property, initial condition or flow rate from a drip source. Following the formal development of the ANN, we have prepared a “user-friendly” version in a spreadsheet environment (in “Excel”). The input data are selected from appropriate values and the output is instantaneous resulting in a picture of the resulting water plume. The MA has also proven valuable, on its own merit, in the description of the flow in soil under laboratory conditions for both wettable and repellant soils. This includes non-Darcian flow examples and redistribution and well as infiltration. Field experiments were conducted in different agricultural fields and various water qualities in Israel. The obtained results will be the basis for the further ANN models development. Regions of high repellence were identified primarily under the canopy of various orchard crops, including citrus and persimmons. Also, increasing OM in the applied water lead to greater repellency. Major scientific implications are that the ANN offers an alternative to conventional flow and transport modeling and that MA is a powerful technique for describing the subsurface water distributions for normal (wettable) and repellant soil. Implications of the field measurements point to the special role of OM in affecting wettability, both from the irrigation water and from soil accumulation below canopies. Implications for agriculture are that a modified approach for drip system design should be adopted for open area crops and orchards, and taking into account the OM components both in the soil and in the applied waters.

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Rubio-Codina, Marta, María Caridad Araujo, Orazio P. Attanasio e Sally Grantham-McGregor. Concurrent Validity and Feasibility of Short Tests Currently Used to Measure Early Childhood Development in Large Scale Studies: Methodology and Results. Inter-American Development Bank, agosto de 2016. http://dx.doi.org/10.18235/0012283.

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In low- and middle-income countries (LIMCs) measuring early childhood development (ECD) with standard tests in large scale surveys (i.e. evaluations of interventions) is difficult and expensive. Multi-dimensional screeners and single-domain tests ('short tests') are frequentlyused as alternatives. However, their validity in these circumstances is unknown. We examine the feasibility, reliability, and concurrent validity of three multi-dimensional screeners -the Ages and Stages Questionnaires (ASQ-3), the Denver Developmental Screening Test (Denver-II), the Battelle Developmental Inventory screener (BDI-2) -and two single-domain tests- the MacArthur-Bates Short-Forms (SFI and SFII) and the WHO Motor Milestones (WHO-Motor)-in 1,311 children 6-42 months in Bogota, Colombia. We compare scores on these short tests to those on the Bayley Scales of Infant and Toddler Development (Bayley-III), which we take as the 'gold standard'. The Bayley-III was given at a center by psychologists; whereas the short tests were administered in the home by interviewers, as in a survey setting. Concurrent validity of the multi-dimensional tests' cognitive, language, and fine motor scales with the corresponding Bayley-III scale is low below 19 months but increases with age, becoming moderate-to-high over 30 months. In contrast, gross motor scales' concurrence is high under 19 months and then decreases. Of the single-domain tests, the WHO-Motor has high validity with gross motor under 16 months, and the SFI and SFII expressive scales show moderate correlations with language under 30 months. Overall, the Denver-II seems the most feasible and valid multi-dimensional test and the ASQ-3 performs poorly under 31 months. By domain, gross motor development has the highest concurrence below 19 months, and language above. Results do not vary by household socio-economic status. Predictive validity investigation is nonetheless needed to further guide the choice of instruments for large scale studies.

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Russo, David, Daniel M. Tartakovsky e Shlomo P. Neuman. Development of Predictive Tools for Contaminant Transport through Variably-Saturated Heterogeneous Composite Porous Formations. United States Department of Agriculture, dezembro de 2012. http://dx.doi.org/10.32747/2012.7592658.bard.

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The vadose (unsaturated) zone forms a major hydrologic link between the ground surface and underlying aquifers. To understand properly its role in protecting groundwater from near surface sources of contamination, one must be able to analyze quantitatively water flow and contaminant transport in variably saturated subsurface environments that are highly heterogeneous, often consisting of multiple geologic units and/or high and/or low permeability inclusions. The specific objectives of this research were: (i) to develop efficient and accurate tools for probabilistic delineation of dominant geologic features comprising the vadose zone; (ii) to develop a complementary set of data analysis tools for discerning the fractal properties of hydraulic and transport parameters of highly heterogeneous vadose zone; (iii) to develop and test the associated computational methods for probabilistic analysis of flow and transport in highly heterogeneous subsurface environments; and (iv) to apply the computational framework to design an “optimal” observation network for monitoring and forecasting the fate and migration of contaminant plumes originating from agricultural activities. During the course of the project, we modified the third objective to include additional computational method, based on the notion that the heterogeneous formation can be considered as a mixture of populations of differing spatial structures. Regarding uncertainly analysis, going beyond approaches based on mean and variance of system states, we succeeded to develop probability density function (PDF) solutions enabling one to evaluate probabilities of rare events, required for probabilistic risk assessment. In addition, we developed reduced complexity models for the probabilistic forecasting of infiltration rates in heterogeneous soils during surface runoff and/or flooding events Regarding flow and transport in variably saturated, spatially heterogeneous formations associated with fine- and coarse-textured embedded soils (FTES- and CTES-formations, respectively).We succeeded to develop first-order and numerical frameworks for flow and transport in three-dimensional (3-D), variably saturated, bimodal, heterogeneous formations, with single and dual porosity, respectively. Regarding the sampling problem defined as, how many sampling points are needed, and where to locate them spatially in the horizontal x₂x₃ plane of the field. Based on our computational framework, we succeeded to develop and demonstrate a methdology that might improve considerably our ability to describe quntitaively the response of complicated 3-D flow systems. The results of the project are of theoretical and practical importance; they provided a rigorous framework to modeling water flow and solute transport in a realistic, highly heterogeneous, composite flow system with uncertain properties under-specified by data. Specifically, they: (i) enhanced fundamental understanding of the basic mechanisms of field-scale flow and transport in near-surface geological formations under realistic flow scenarios, (ii) provided a means to assess the ability of existing flow and transport models to handle realistic flow conditions, and (iii) provided a means to assess quantitatively the threats posed to groundwater by contamination from agricultural sources.

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Anderson, Gerald L., e Kalman Peleg. Precision Cropping by Remotely Sensed Prorotype Plots and Calibration in the Complex Domain. United States Department of Agriculture, dezembro de 2002. http://dx.doi.org/10.32747/2002.7585193.bard.

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This research report describes a methodology whereby multi-spectral and hyperspectral imagery from remote sensing, is used for deriving predicted field maps of selected plant growth attributes which are required for precision cropping. A major task in precision cropping is to establish areas of the field that differ from the rest of the field and share a common characteristic. Yield distribution f maps can be prepared by yield monitors, which are available for some harvester types. Other field attributes of interest in precision cropping, e.g. soil properties, leaf Nitrate, biomass etc. are obtained by manual sampling of the filed in a grid pattern. Maps of various field attributes are then prepared from these samples by the "Inverse Distance" interpolation method or by Kriging. An improved interpolation method was developed which is based on minimizing the overall curvature of the resulting map. Such maps are the ground truth reference, used for training the algorithm that generates the predicted field maps from remote sensing imagery. Both the reference and the predicted maps are stratified into "Prototype Plots", e.g. 15xl5 blocks of 2m pixels whereby the block size is 30x30m. This averaging reduces the datasets to manageable size and significantly improves the typically poor repeatability of remote sensing imaging systems. In the first two years of the project we used the Normalized Difference Vegetation Index (NDVI), for generating predicted yield maps of sugar beets and com. The NDVI was computed from image cubes of three spectral bands, generated by an optically filtered three camera video imaging system. A two dimensional FFT based regression model Y=f(X), was used wherein Y was the reference map and X=NDVI was the predictor. The FFT regression method applies the "Wavelet Based", "Pixel Block" and "Image Rotation" transforms to the reference and remote images, prior to the Fast - Fourier Transform (FFT) Regression method with the "Phase Lock" option. A complex domain based map Yfft is derived by least squares minimization between the amplitude matrices of X and Y, via the 2D FFT. For one time predictions, the phase matrix of Y is combined with the amplitude matrix ofYfft, whereby an improved predicted map Yplock is formed. Usually, the residuals of Y plock versus Y are about half of the values of Yfft versus Y. For long term predictions, the phase matrix of a "field mask" is combined with the amplitude matrices of the reference image Y and the predicted image Yfft. The field mask is a binary image of a pre-selected region of interest in X and Y. The resultant maps Ypref and Ypred aremodified versions of Y and Yfft respectively. The residuals of Ypred versus Ypref are even lower than the residuals of Yplock versus Y. The maps, Ypref and Ypred represent a close consensus of two independent imaging methods which "view" the same target. In the last two years of the project our remote sensing capability was expanded by addition of a CASI II airborne hyperspectral imaging system and an ASD hyperspectral radiometer. Unfortunately, the cross-noice and poor repeatability problem we had in multi-spectral imaging was exasperated in hyperspectral imaging. We have been able to overcome this problem by over-flying each field twice in rapid succession and developing the Repeatability Index (RI). The RI quantifies the repeatability of each spectral band in the hyperspectral image cube. Thereby, it is possible to select the bands of higher repeatability for inclusion in the prediction model while bands of low repeatability are excluded. Further segregation of high and low repeatability bands takes place in the prediction model algorithm, which is based on a combination of a "Genetic Algorithm" and Partial Least Squares", (PLS-GA). In summary, modus operandi was developed, for deriving important plant growth attribute maps (yield, leaf nitrate, biomass and sugar percent in beets), from remote sensing imagery, with sufficient accuracy for precision cropping applications. This achievement is remarkable, given the inherently high cross-noice between the reference and remote imagery as well as the highly non-repeatable nature of remote sensing systems. The above methodologies may be readily adopted by commercial companies, which specialize in proving remotely sensed data to farmers.

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