Testing Computational Algorithms for Unsaturated Flow

Буксируемый подводный модуль (БПМ) эффективно используется для решения задач, связанных с координированием подводных объектов, местоположение которых подлежит уточнению в процессе их детальногообследования. При этом большое значение имеет точность определения координат самого буксируемогомодуля относительно судна-буксировщика. Использование гидроакустических навигационных средств, вчастности систем с ультракороткой базой (ГАНС УКБ), ограничено вследствие помех, влияющих на качествосигналов в приемной антенне. Альтернативой служит метод определения координат БПМ на основе данныхтраекторных измерений параметров буксируемой системы. К числу последних относятся расчетные значенияпараметров кабеля связи в установившихся режимах буксировки, значения путевой скорости и путевого углабуксировщика, а также измеренные значения длины кабеля, глубины погружения и курса БПМ. В работе дансравнительный анализ различных вариантов вычислительных алгоритмов, позволяющих получить оценки точности определения координат БПМ в различных режимах стационарной буксировки и при наличии сбоев вработе навигационных средств.The towed underwater module (TUM) is a useful toolfor solving problems of the positioning of the underwaterobjects, the location of which must be clarified during its detailedinspection. Herewith, the accuracy of the determinationof the coordinates of the towed module itself relative tothe towing vessel is essential for such kind of problems. Theuse of underwater acoustic navigation means, the systemswith ultra-short baseline (USBL) in particular, are limiteddue to interference affecting the quality of the signals on thereceiving antenna. As an alternative, the method is proposedfor TUM positioning based on trajectory measurements ofparameters of the towed system, which may include calculatedvalues of communication cable parameters in steadystatetowing modes, values of ground speed and towing angle,as well as measured cable length, immersion depth, andTUM heading. The paper provides a comparative analysisof various versions of computational algorithms, which allowobtaining estimates of the TUM positioning accuracy indifferent modes of stationary towing and in the presence offailures in navigation systems operation.

Download Full-text

Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow

Hydrology Research ◽

10.2166/nh.1992.0007 ◽

1992 ◽

Vol 23 (2) ◽

pp. 89-104 ◽

Cited By ~ 30

Author(s):

Ole H. Jacobsen ◽

Feike J. Leij ◽

Martinus Th. van Genuchten

Keyword(s):

Experimental Data ◽

Unsaturated Flow ◽

Transport Model ◽

Time Moment ◽

Breakthrough Curves ◽

Coarse Sand ◽

Retardation Factor ◽

Parameter Determination ◽

Model Parameters ◽

Water Fraction

Breakthrough curves of Cl and 3H2O were obtained during steady unsaturated flow in five lysimeters containing an undisturbed coarse sand (Orthic Haplohumod). The experimental data were analyzed in terms of the classical two-parameter convection-dispersion equation and a four-parameter two-region type physical nonequilibrium solute transport model. Model parameters were obtained by both curve fitting and time moment analysis. The four-parameter model provided a much better fit to the data for three soil columns, but performed only slightly better for the two remaining columns. The retardation factor for Cl was about 10 % less than for 3H2O, indicating some anion exclusion. For the four-parameter model the average immobile water fraction was 0.14 and the Peclet numbers of the mobile region varied between 50 and 200. Time moments analysis proved to be a useful tool for quantifying the break through curve (BTC) although the moments were found to be sensitive to experimental scattering in the measured data at larger times. Also, fitted parameters described the experimental data better than moment generated parameter values.

Download Full-text

Microstructures in Elastic Media

10.1093/oso/9780195090864.001.0001 ◽

1994 ◽

Cited By ~ 1

Author(s):

Nhan Phan-Thien ◽

Sangtae Kim

Keyword(s):

Computational Methods ◽

High Performance ◽

Chemical Engineering ◽

Elliptic Partial Differential Equations ◽

Parallel Computers ◽

Computational Algorithms ◽

Applied Physics ◽

Advanced Students ◽

Particulate Solids ◽

Modeling Software

This monograph describes various methods for solving deformation problems of particulate solids, taking the reader from analytical to computational methods. The book is the first to present the topic of linear elasticity in mathematical terms that will be familiar to anyone with a grounding in fluid mechanics. It incorporates the latest advances in computational algorithms for elliptic partial differential equations, and provides the groundwork for simulations on high performance parallel computers. Numerous exercises complement the theoretical discussions, and a related set of self-documented programs is available to readers with Internet access. The work will be of interest to advanced students and practicing researchers in mechanical engineering, chemical engineering, applied physics, computational methods, and developers of numerical modeling software.

Download Full-text

Computational Algorithms for Censored-Data Problems Using Intersection Graphs

Journal of Computational and Graphical Statistics ◽

10.1198/106186001317114901 ◽

2001 ◽

Vol 10 (3) ◽

pp. 403-421 ◽

Cited By ~ 31

Author(s):

R Gentleman ◽

A. C Vandal

Keyword(s):

Censored Data ◽

Computational Algorithms ◽

Intersection Graphs

Download Full-text

An isotropic elasto-damage-plastic micromechanical framework of innovative pothole patching materials featuring high-toughness, low-viscosity nanomolecular resin

International Journal of Damage Mechanics ◽

10.1177/10567895211028649 ◽

2021 ◽

pp. 105678952110286

Author(s):

H Zhang ◽

J Woody Ju ◽

WL Zhu ◽

KY Yuan

Keyword(s):

Strain Energy ◽

Three Dimensional ◽

Elastic Strain Energy ◽

Companion Paper ◽

Computational Algorithms ◽

Mechanical Behaviors ◽

High Toughness ◽

Low Viscosity ◽

Innovative Materials ◽

Continuum Thermodynamic

In a recent companion paper, a three-dimensional isotropic elastic micromechanical framework was developed to predict the mechanical behaviors of the innovative asphalt patching materials reinforced with a high-toughness, low-viscosity nanomolecular resin, dicyclopentadiene (DCPD), under the splitting tension test (ASTM D6931). By taking advantage of the previously proposed isotropic elastic-damage framework and considering the plastic behaviors of asphalt mastic, a class of elasto-damage-plastic model, based on a continuum thermodynamic framework, is proposed within an initial elastic strain energy-based formulation to predict the behaviors of the innovative materials more accurately. Specifically, the governing damage evolution is characterized through the effective stress concept in conjunction with the hypothesis of strain equivalence; the plastic flow is introduced by means of an additive split of the stress tensor. Corresponding computational algorithms are implemented into three-dimensional finite elements numerical simulations, and the outcomes are systemically compared with suitably designed experimental results.

Download Full-text

Exact computer realization of certain computational algorithms

Journal of Soviet Mathematics ◽

10.1007/bf01296244 ◽

1980 ◽

Vol 13 (2) ◽

pp. 281-285 ◽

Cited By ~ 1

Author(s):

A. A. Aleksandrova ◽

T. N. Smirnova

Keyword(s):

Computational Algorithms ◽

Computer Realization ◽

Exact Computer

Download Full-text

Smartphones for Remote Symptom Monitoring of Parkinson’s Disease

Journal of Parkinson s Disease ◽

10.3233/jpd-202453 ◽

2021 ◽

pp. 1-5

Author(s):

Max A. Little

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Symptom Severity ◽

Computational Analysis ◽

Computational Algorithms ◽

Objective Data ◽

Future Prospects ◽

Symptom Monitoring ◽

Sensor Devices ◽

Symptoms And Signs

Parkinson’s disease is a complex and heterogeneous condition, and there are many gaps in the medical community’s scientific and practical understanding of the disease. Closing these gaps relies on objective data about symptoms and signs, collected over long durations. Smartphones contain sensor devices which can be used to remotely capture behavioral signals. From these signals, computational algorithms can distill metrics of symptom severity and progression. This brief review introduces the main concepts of the discipline, addressing the experimental, hardware and software logistics, and computational analysis. The article finishes with an exploration of future prospects for the technology.

Download Full-text