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A new approach termed as the hybrid displacement-strain-based normalized time-weighted residual approach is presented to accurately model non-linear structural dynamic problems. The focus here is restricted to all possible algorit...
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A new approach termed as the hybrid displacement-strain-based normalized time-weighted residual approach is presented to accurately model non-linear structural dynamic problems. The focus here is restricted to all possible algorithmic designs within the class of linear multi-step methods that fall under the umbrella of the generalized single solve single step linear dynamic framework originally developed via the classical time-weighted residual approach involving a single solve within each time step as such designs are the most predominant in research and commercial software (Int. J. Numer Meth. Engng 2004; 59:597-668; Int. J. Numer Meth. Engng 2006; 66:1738-1790). However, traditional practices via classical time-weighted residual approaches fail to preserve the underlying physics and stability and do not serve the purposes of extensions to non-linear dynamic situations. In contrast, a new normalized time-weighted residual approach is proposed that naturally enables such extensions leading to the design of a family of conserving time operators for unconstrained conservative dynamic systems without resorting to enforcing energy constraints as in past practices. Consequently, the algorithmic stability (in the sense of energy stability) via this approach for non-linear dynamic problems is also preserved. For linear dynamic situations, it reverts to the classical paradigm. Only simple numerical illustrations are purposely presented to demonstrate the basic concepts.
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Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemist...
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Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemistry and bioactivity of compounds isolated from all kinds of starfish to illustrate the chemodiversity and biological significance of these constituents, along with their geographical distribution where it is discernible.
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This paper introduces TRIPLEX-GHG, a new process-based model framework used to quantify terrestrial ecosystem greenhouse gas dynamics by incorporating both ecological drivers and biogeochemical processes. TRIPLEX-GHG was developed from the Integ
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Crucial inputs for a variety of CP-violation studies can be determined through the analysis of pairs of quantum-entangled neutral D mesons, which are produced in the decay of the psi(3770) resonance. The relative strong-phase para...
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Crucial inputs for a variety of CP-violation studies can be determined through the analysis of pairs of quantum-entangled neutral D mesons, which are produced in the decay of the psi(3770) resonance. The relative strong-phase parameters between D-0 and (D) over bar (0) in the decays D-0 -> K-S,L(0)pi(+)pi(-) are studied using 2.93 fb(-1) of e(+)e(-) annihilation data delivered by the BEPCII collider and collected by the BESIII detector at a center-of-mass energy of 3.773 GeV. Results are presented in regions of the phase space of the decay. These are the most precise measurements to date of the strong-phase parameters in D-0 -> K-S,L(0)pi(+)pi(-) decays. Using these parameters, the associated uncertainty on the Cabibbo-Kobayashi-Maskawa angle gamma/phi(3) is expected to be between 0.7 degrees and 1.2 degrees for an analysis using the decay B-+/- -> DK +/-, D -> K-S(0)pi(+)pi(-), where D represents a superposition of D-0 and (D) over bar (0) states. This is a factor of 3 smaller than that achievable with previous measurements. Furthermore, these results provide valuable input for charm-mixing studies, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.
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Using a new design procedure termed as Algorithms by Design, which we have successfully introduced in our previous efforts for second-order systems, alternatively, we advance in this exposition, the design and development of a com...
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Using a new design procedure termed as Algorithms by Design, which we have successfully introduced in our previous efforts for second-order systems, alternatively, we advance in this exposition, the design and development of a computational framework that permits order-preserving second-order time accurate, unconditionally stable, zero-order overshooting behavior, and features with controllable numerical dissipation and dispersion via a family of algorithms for effectively solving transient first-order systems. The key feature is the incorporation of a spurious root to introduce controllable numerical dissipation while preserving second-order accuracy (order-preserving feature) resulting in a two-root system, namely, the principal root (ρ_(1∞)) and a spurious root (ρ_(2∞)). In contrast to the classical Trapezoidal family of algorithms which are the most popular, the present framework has the same order of computational complexity, but a higher payoff that is a significant advance to the field for tackling a wide class of applications dealing with first-order transient systems. We also present the special case with selection of ρ_(1∞) = 1 and any ρ_(2∞) leading to the design of a family of generalized single-step single-solve [GS4-1] algorithms recovering the Crank-Nicolson method at one end (ρ_(2∞) = 1) and the Midpoint Rule at the other end (ρ_(2∞) = 0) and anything in between, all of which have spectral radius features resembling that of the Crank-Nicolson method. More interestingly, with the particular choice of ρ_(1∞) = ρ_(2∞) = 0, the developed framework additionally inherits L-stable features. We illustrate the successful design of the developed GS4-1 framework using two simple illustrative numerical examples.
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Using the solution of one-sided exit problem, a procedure to price Parisian barrier options in a jump-diffusion model with two-sided exponential jumps is developed. By extending the method developed in Chesney, Jeanblanc-Picqué a...
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Using the solution of one-sided exit problem, a procedure to price Parisian barrier options in a jump-diffusion model with two-sided exponential jumps is developed. By extending the method developed in Chesney, Jeanblanc-Picqué and Yor (1997; Brownian excursions and Parisian barrier options, Advances in Applied Probability, 29(1), pp. 165-184) for the diffusion case to the more general set-up, we arrive at a numerical pricing algorithm that significantly outperforms Monte Carlo simulation for the prices of such products.
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Recent advances in cone-beam computed tomography (CBCT) have rapidly enabled widepsread applications of dentomaxillofacial imaging and orthodontic practices in the past decades due to its low radiation dose, high spatial resolutio...
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Recent advances in cone-beam computed tomography (CBCT) have rapidly enabled widepsread applications of dentomaxillofacial imaging and orthodontic practices in the past decades due to its low radiation dose, high spatial resolution, and accessibility. However, low contrast resolution in CBCT image has become its major limitation in building skull models. Intensive hand-segmentation is usually required to reconstruct the skull models. One of the regions affected by this limitation the most is the thin bone images. This paper presents a novel segmentation approach based on wavelet density model (WDM) for a particular interest in the outer surface of anterior wall of maxilla. Nineteen CBCT datasets are used to conduct two experiments. This mode-based segmentation approach is validated and compared with three different segmentation approaches. The results show that the performance of this model-based segmentation approach is better than those of the other approaches. It can achieve 0.25 ± 0.2 mm of surface error from ground truth of bone surface.
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Tree index structures are crucial components in data management systems. Existing tree index structure are designed with the implicit assumption that the underlying external memory storage is the conventional magnetic hard disk dr...
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Tree index structures are crucial components in data management systems. Existing tree index structure are designed with the implicit assumption that the underlying external memory storage is the conventional magnetic hard disk drives. This assumption is going to be invalid soon, as flash memory storage is increasingly adopted as the main storage media in mobile devices, digital cameras, embedded sensors, and notebooks. Though it is direct and simple to port existing tree index structures on the flash memory storage, that direct approach does not consider the unique characteristics of flash memory, i.e., slow write operations, and erase-before-update property, which would result in a sub optimal performance. In this paper, we introduce FAST (i.e., Flash-Aware Search Trees) as a generic framework for flash-aware tree index structures. FAST distinguishes itself from all previous attempts of flash memory indexing in two aspects: (1) FAST is a generic framework that can be applied to a wide class of data partitioning tree structures including R-tree and its variants, and (2) FAST achieves both efficiency and durability of read and write flash operations through memory flushing and crash recovery techniques. Extensive experimental results, based on an actual implementation of FAST inside the GiST index structure in PostgreSQL, show that FAST achieves better performance than its competitors.
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Deoxyribonucleic acid (DNA) barcoding is an effective tool for species identification and life-stage association in a wide range of animal taxa. We developed a strategy for rapid construction of a regional DNA-barcode reference li...
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Deoxyribonucleic acid (DNA) barcoding is an effective tool for species identification and life-stage association in a wide range of animal taxa. We developed a strategy for rapid construction of a regional DNA-barcode reference library and used the caddisflies (Trichoptera) of the Great Smoky Mountains National Park (GSMNP) as a model. Nearly 1000 cytochrome c oxidase subunit I (COI) sequences, representing 209 caddisfly species previously recorded from GSMNP, were obtained from the global Trichoptera Barcode of Life campaign. Most of these sequences were collected from outside the GSMNP area. Another 645 COI sequences, representing 80 species, were obtained from specimens collected in a 3-d bioblitz (short-term, intense sampling program) in GSMNP. The joint collections provided barcode coverage for 212 species, 91% of the GSMNP fauna. Inclusion of samples from other localities greatly expedited construction of the regional DNA-barcode reference library. This strategy increased intraspecific divergence and decreased average distances to nearest neighboring species, but the DNA-barcode library was able to differentiate 93% of the GSMNP Trichoptera species examined. Global barcoding projects will aid construction of regional DNA-barcode libraries, but local surveys make crucial contributions to progress by contributing rare or endemic species and full-length barcodes generated from high-quality DNA. DNA taxonomy is not a goal of our present work, but the investigation of COI divergence patterns in caddisflies is providing new insights into broader biodiversity patterns in this group and has directed attention to various issues, ranging from the need to re-evaluate species taxonomy with integrated morphological and molecular evidence to the necessity of an appropriate interpretation of barcode analyses and its implications in understanding species diversity (in contrast to a simple claim for barcoding failure).
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