1,867 research outputs found
Multiple positive solutions to third-order three-point singular semipositone boundary value problem
By using a specially constructed cone and the fixed point index theory, this
paper investigates the existence of multiple positive solutions for the
third-order three-point singular semipositone BVP: \begin{cases} x'''(t)-\ld
f(t,x) =0, &t\in(0,1); [.3pc] x(0)=x'(\eta)=x''(1)=0, & \end{cases} where
, the non-linear term f(t,x):(0,1)\times(0,+\i)\to (-\i,+\i) is
continuous and may be singular at , , and , also may be negative
for some values of and , \ld is a positive parameter.Comment: 14 page
Design and analysis of a novel long-distance double tendon-sheath transmission device for breast intervention robots under MRI field
Cancer represents a major threat to human health. Magnetic resonance imaging (MRI) provides superior performance to other imaging-based examination methods in the detection of tumors and offers distinct advantages in biopsy and seed implantation. However, because of the MRI environment, the material requirements for actuating devices for the medical robots used in MRI are incredibly demanding. This paper describes a novel double tendon-sheath transmission device for use in MRI applications. LeBus grooves are used in the original transmission wheels, thus enabling the system to realize long-distance and large-stroke transmission with improved accuracy. The friction model of the transmission system and the transmission characteristics model of the novel tendon-sheath structure are then established. To address the problem that tension sensors cannot be installed in large-stroke transmission systems, a three-point force measurement method is used to measure and set an appropriate preload in the novel tendon-sheath transmission system. Additionally, experiments are conducted to verify the accuracy of the theoretical model and multiple groups of tests are performed to explore the transmission characteristics. Finally, the novel tendon-sheath transmission system is compensated to improve its accuracy and the experimental results acquired after compensation show that the system satisfies the design requirements
Measuring and assessing HIV/AIDS stigma and discrimination among migrant workers in Zhejiang, China
Abstract Background The aim of this study was to develop a Chinese HIV/AIDS Stigma Scale (C-HSS) and test its reliability and validity among migrant workers in eastern China. Methods Nine hundred sixty four migrant workers completed the C-HSS questionnaire in Zhejiang province. The Split-half reliability coefficient (R) and Cronbach’s alpha coefficient (a) for internal consistency of the scale were used. Factor analysis was applied for construct validity. Scores of total and subscales were compared among migrants. Correlation between scores and knowledge of HIV/AIDS was analyzed. Results The 24-items scale and the four subscales of C-HSS had good internal consistency (R overall was 0.877, subscales ranged from 0.693 to 0.862; Cronbach’s alpha overall was 0.845, subscales ranged from 0.709 to 0.810). Correlation coefficients between each domain and total score were significant (p < 0.01). The cumulative contribution rate was 54.17 % by five public factors based on exploratory factor analysis. Except for the thirteenth item and twentieth item, four public factors were in accordance with the basic conceived concept. The confirmatory factor analysis indicated a good fit to the data for the four-domain structure. Negative correlation existed between the level of HIV/AIDS knowledge and stigma. Conclusion The results suggest that the C-HSS is a reliable and valid measure for HIV/AIDS stigma in migrant workers
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An Application on Text Classification Based on Granular Computing
Machine learning is the key to text classification, a granular computing approach to machine learning is applied to learning classification rules by considering the two basic issues: concept formation and concept relationships identification. In this paper, we concentrate on the selection of a single granule in each step to construct a granule network. A classification rule induction method is proposed
Collaborative Aggregation of Individual Rating for Group Evaluation
The aggregation of individual evaluations into a group evaluation is a key issue in decision theory. Inspired by the collaboration idea on Web2.0, two group evaluation methods of collaborative weighting evaluators where evaluators rate the objects evaluated are presented to form group decision. Among the most commonly applied methods for group evaluation are to average the scores obtained by each objects evaluated and then consider the associated collective evaluation, which not consider the difference between individual evaluators. The proposed methods can offset the effect resulted by some evaluator’s irregular evaluation through considering the contribution of the individual evaluation to the collective evaluation. Sometimes the irregularity is owing to the subjectivity reason. For example, since some evaluators are prejudiced against some objects evaluated, the evaluators will subjectivity give very high or very low rating on the objects evaluated. In this paper, two nonlinear group evaluation methods achieved through mutual restraints between individual evaluators and consequently are more stable than traditional group evaluation method in an actual example and a synthetic data set
The Trapping and Characterization of a Single Hydrogen Molecule in a Continuously Tunable Nanocavity
Using inelastic electron tunneling spectroscopy with the scanning tunneling
microscope (STM-IETS) and density functional theory calculations (DFT), we
investigated properties of a single H2 molecule trapped in nanocavities with
controlled shape and separation between the STM tip and the Au (110) surface.
The STM tip not only serves for the purpose of characterization, but also is
directly involved in modification of chemical environment of molecule. The bond
length of H2 expands in the atop cavity, with a tendency of dissociation when
the gap closes, whereas it remains unchanged in the trough cavity. The
availability of two substantially different cavities in the same setup allows
understanding of H2 adsorption on noble metal surfaces and sets a path for
manipulating a single chemical bond by design.Comment: 11 pages, 4 figure
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