785 research outputs found
A least-squares implicit RBF-FD closest point method and applications to PDEs on moving surfaces
The closest point method (Ruuth and Merriman, J. Comput. Phys.
227(3):1943-1961, [2008]) is an embedding method developed to solve a variety
of partial differential equations (PDEs) on smooth surfaces, using a closest
point representation of the surface and standard Cartesian grid methods in the
embedding space. Recently, a closest point method with explicit time-stepping
was proposed that uses finite differences derived from radial basis functions
(RBF-FD). Here, we propose a least-squares implicit formulation of the closest
point method to impose the constant-along-normal extension of the solution on
the surface into the embedding space. Our proposed method is particularly
flexible with respect to the choice of the computational grid in the embedding
space. In particular, we may compute over a computational tube that contains
problematic nodes. This fact enables us to combine the proposed method with the
grid based particle method (Leung and Zhao, J. Comput. Phys. 228(8):2993-3024,
[2009]) to obtain a numerical method for approximating PDEs on moving surfaces.
We present a number of examples to illustrate the numerical convergence
properties of our proposed method. Experiments for advection-diffusion
equations and Cahn-Hilliard equations that are strongly coupled to the velocity
of the surface are also presented
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Gender-specific profiles of adverse childhood experiences, past year mental and substance use disorders, and their associations among a national sample of adults in the United States
Purpose: This study examined profiles of adverse childhood experiences (ACEs) and mental and substance use disorders (MSUDs), and associations between distinct profiles of ACEs and MSUDs. Methods: Participants were adults (N = 34, 652) involved in the National Epidemiologic Survey on Alcohol and Related Conditions. Latent class analysis was used to examine both profiles of ten ACEs and ten past year MSUDs. Dual latent class analysis regression was used to examine associations between profiles of ACEs and MSUDs. Given gender differences in ACEs and MSUDs, analyses were conducted separately for females and males. Results: Four profiles of ACEs and three profiles of MSUDs were selected for both genders. The four profiles of ACEs were characterized by the following probabilities: high multiple ACEs, high parental substance abuse, high childhood physical abuse, and low ACEs. The three profiles of MSUDs were characterized by the following probabilities: high multiple MSUDs for females and low MSUDs except alcohol use disorders for males, moderate-to-high major depressive episode, and low MSUDs. When compared to the low ACEs and MSUDs profiles, members in the higher ACEs profiles had 3.71–89.75 times greater odds of also being members in the higher MSUDs profiles. However, more than one-third of members in the high multiple ACEs profiles were also in the low MSUDs profiles. Conclusions: Study findings suggest four profiles of the ACEs widely studied as part of the Adverse Childhood Experiences study and risk and resilience for recent MSUDs among men and women nationally affected by ACEs
Fuzzy reactive piloting for continuous driving of long range autonomous planetary micro-rovers
Abstract — A complete piloting control subsystem for a highly autonomous long range rover will be defined in order to identify the key control functions needed to achieve contin-uous driving. This capability can maximize range and num-ber of interesting scientific sites visited during the limited life time of a planetary rover. To achieve continuous driving, a complete set of techniques have been employed: fuzzy based control, real-time artificial intelligence reasoning, fast and ro-bust rover position estimation based on odometry and angu-lar rate sensing, efficient stereo vision elevation maps based on grids, and fast reaction and planning for obstacle detec-tion and obstacle avoidance based on a simple IF-THEN ex-pert system with fuzzy reasoning. To quickly design and im-plement these techniques, graphical programming has been used to build a fully autonomous piloting system using jus
Application of Management Audit for Increasing Economic Efficiency of State-Owned Enterprises Activities
To substantiate the direction of the research, this paper establishes the factors which affect performance efficiency of state-owned enterprises (SOEs). The authors' analyse the effect of management control on the economic efficiency of activities of state-owned enterprises by application of management audit. The paper seeks to highlight the higher utility of economic activity as well as return of capital which was used in the process of activities. The paper analyses the quality of management and economic activity in SOEs based on scientific literature as well as reports and decisions of the representative government institutions as well as the results of empirical research which was accomplished in Lithuania. The paper stresses that the state-owned commercial property in Lithuania has thus far been managed inefficiently. Unlike private companies, SOEs practically fail to render much use to the state. This fact does not allow SOE's to reach the highest economic benefit. Accordingly, the authors' present an innovative approach towards the improvement of the management of SOEs economic activities through application of the audit principles, which traditionally are associated with the assessments of financial activity. The proposed model can be further extended and employed in other countries of Northern Europe, specifically in Latvia, Estonia and other Post-Soviet countries
Browser-Based Application for Telemetry Monitoring of Robotic Assets
AEGSE Virtuoso Charting is an application that enables animated, real-time charting of telemetry streams of data from a rover. These automatically scaled charts are completely interactive, and allow users to choose the variables that they want to monitor. The charts can process data from streams with many variables. This application allows for the simultaneous viewing of up to four individually configured charts on a small touch-screen laptop. The charting application has been tested and found to be extremely robust during long operations. It was left running overnight, with incoming telemetry at 100 Hz, and it did not experience any signs of lost functionality or memory leaks. This robustness is critical for an application that will be used to support vital tests for the Mars Science Laboratory rover. The charting component also provides an interactive interface that allows the engineers to decide how many charts they want on their screen, and which attributes should be plotted on each chart. The application is optimized to make the charts on display take up as much of the available space as possible to maximize the use of the screen real estate. Engineers are also able to plot multiple attributes on the same chart, which enables them to observe the correlation between various attributes
Identification of a gonadotropin-releasing hormone receptor orthologue in Caenorhabditis elegans
BACKGROUND: The Caenorhabditis elegans genome is known to code for at least 1149 G protein-coupled receptors (GPCRs), but the GPCR(s) critical to the regulation of reproduction in this nematode are not yet known. This study examined whether GPCRs orthologous to human gonadotropin-releasing hormone receptor (GnRHR) exist in C. elegans. RESULTS: Our sequence analyses indicated the presence of two proteins in C. elegans, one of 401 amino acids [GenBank: NP_491453; WormBase: F54D7.3] and another of 379 amino acids [GenBank: NP_506566; WormBase: C15H11.2] with 46.9% and 44.7% nucleotide similarity to human GnRHR1 and GnRHR2, respectively. Like human GnRHR1, structural analysis of the C. elegans GnRHR1 orthologue (Ce-GnRHR) predicted a rhodopsin family member with 7 transmembrane domains, G protein coupling sites and phosphorylation sites for protein kinase C. Of the functionally important amino acids in human GnRHR1, 56% were conserved in the C. elegans orthologue. Ce-GnRHR was actively transcribed in adult worms and immunoanalyses using antibodies generated against both human and C. elegans GnRHR indicated the presence of a 46-kDa protein, the calculated molecular mass of the immature Ce-GnRHR. Ce-GnRHR staining was specifically localized to the germline, intestine and pharynx. In the germline and intestine, Ce-GnRHR was localized specifically to nuclei as revealed by colocalization with a DNA nuclear stain. However in the pharynx, Ce-GnRHR was localized to the myofilament lattice of the pharyngeal musculature, suggesting a functional role for Ce-GnRHR signaling in the coupling of food intake with reproduction. Phylogenetic analyses support an early evolutionary origin of GnRH-like receptors, as evidenced by the hypothesized grouping of Ce-GnRHR, vertebrate GnRHRs, a molluscan GnRHR, and the adipokinetic hormone receptors (AKHRs) and corazonin receptors of arthropods. CONCLUSION: This is the first report of a GnRHR orthologue in C. elegans, which shares significant similarity with insect AKHRs. In vertebrates, GnRHRs are central components of the reproductive endocrine system, and the identification of a GnRHR orthologue in C. elegans suggests the potential use of C. elegans as a model system to study reproductive endocrinology
Quantum algorithm and circuit design solving the Poisson equation
The Poisson equation occurs in many areas of science and engineering. Here we
focus on its numerical solution for an equation in d dimensions. In particular
we present a quantum algorithm and a scalable quantum circuit design which
approximates the solution of the Poisson equation on a grid with error
\varepsilon. We assume we are given a supersposition of function evaluations of
the right hand side of the Poisson equation. The algorithm produces a quantum
state encoding the solution. The number of quantum operations and the number of
qubits used by the circuit is almost linear in d and polylog in
\varepsilon^{-1}. We present quantum circuit modules together with performance
guarantees which can be also used for other problems.Comment: 30 pages, 9 figures. This is the revised version for publication in
New Journal of Physic
An evaluation of Bradfordizing effects
The purpose of this paper is to apply and evaluate the bibliometric method Bradfordizing for information retrieval (IR) experiments. Bradfordizing is used for generating core document sets for subject-specific questions and to reorder result sets from distributed searches. The method will be applied and tested in a controlled scenario of scientific literature databases from social and political sciences, economics, psychology and medical science (SOLIS, SoLit, USB Köln Opac, CSA Sociological Abstracts, World Affairs Online, Psyndex and Medline) and 164 standardized topics. An evaluation of the method and its effects is carried out in two laboratory-based information retrieval experiments (CLEF and KoMoHe) using a controlled document corpus and human relevance assessments. The results show that Bradfordizing is a very robust method for re-ranking the main document types (journal articles and monographs) in today’s digital libraries (DL). The IR tests show that relevance distributions after re-ranking improve at a significant level if articles in the core are compared with articles in the succeeding zones. The items in the core are significantly more often assessed as relevant, than items in zone 2 (z2) or zone 3 (z3). The improvements between the zones are statistically significant based on the Wilcoxon signed-rank test and the paired T-Test
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