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  • Author: Jin Yan x
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Dynamic Probability Fields for Risk Assessment and Guidance Solutions

Abstract

Standard Guidance, Navigation, and Control (GN&C) systems take state data from a navigation system and create a trajectory that minimizes some a-priori determined cost function. These cost functions are typically time, money, weight, or any general physically realizable quantity. Previous work has been done to show the effectiveness of using risk as the sole objective function. However, this previous work used Poisson distributions and historical estimates to achieve this goal. In this paper we present the situation-risk assessment (SRA) method contained within the intelligent situation assessment and collision avoidance (iSC) platform. The SRA method uses data clustering, and pattern recognition to create a historically based estimate of guidance probabilities. These are then used in data driven, dynamic models to create the future probability fields of the situation. This probability, along with the other agent’s goals and objectives, are then used to create a minimum risk guidance solution in the nautical environment.

Open access
Reliability Estimation Based on the Degradation Amount Distribution Using Composite Time Series Analysis and Grey Theory

Abstract

This paper puts forward a reliability estimation method by the Degradation Amount Distribution (DAD) of products, using a composite time series modeling procedure and grey theory based on a random failure threshold. Product DAD data are treated as a composite time series and described using a composite time series model to predict a long-term trend of degradation. The degradation test is processed for a certain electronic product and the degradation data is collected for reliability estimation. Comparison among the reliability evaluation by DAD composite time series analysis and grey theory, based on a constant and a random failure threshold, reliability evaluation by DAD regression analysis based on a random failure threshold, reliability evaluation by degradation path time series analysis, and real reliability of the electronic product is done. The results show that the reliability evaluation of the product using the method proposed is the most creditable of all.

Open access
On the Number of Disjoint 4-Cycles in Regular Tournaments

Abstract

In this paper, we prove that for an integer r ≥ 1, every regular tournament T of degree 3r − 1 contains at least 2116r-103 disjoint directed 4-cycles. Our result is an improvement of Lichiardopol’s theorem when taking q = 4 [Discrete Math. 310 (2010) 2567–2570]: for given integers q ≥ 3 and r ≥ 1, a tournament T with minimum out-degree and in-degree both at least (q − 1)r − 1 contains at least r disjoint directed cycles of length q.

Open access
Conservative finite volume element schemes for the complex modified Korteweg–de Vries equation

Abstract

The aim of this paper is to build and validate a class of energy-preserving schemes for simulating a complex modified Korteweg–de Vries equation. The method is based on a combination of a discrete variational derivative method in time and finite volume element approximation in space. The resulting scheme is accurate, robust and energy-preserving. In addition, for comparison, we also develop a momentum-preserving finite volume element scheme and an implicit midpoint finite volume element scheme. Finally, a complete numerical study is developed to investigate the accuracy, conservation properties and long time behaviors of the energy-preserving scheme, in comparison with the momentum-preserving scheme and the implicit midpoint scheme, for the complex modified Korteweg–de Vries equation.

Open access
Development and application of a closed-loop medication administration system in University of Hongkong-Shenzhen Hospital

Abstract

Objective

This study aimed to develop and apply a closed-loop medication administration system in a hospital in order to reduce medication administration errors (MAEs).

Methods

The study was implemented in four pilot general wards. We used a before-and-after design to collect oral medication administration times before and after the implementation of the closed-loop medication administration system, evaluated MAE alert logs after the intervention, and conducted a survey of the nurses’ satisfaction with the system in the pilot wards.

Results

(a) Nursing time of oral medication administration: before the adoption of the closed-loop medication administration system, the average nursing time was 31.56 ± 10.88 minutes (n = 78); after the adoption of the system, the time was 18.74 ± 5.60 minutes (n = 54). Independent sample t-tests showed a significant difference between two groups (t = 8.85, P <0.00). (b) Degree of nurses’ satisfaction with the closed-loop medication administration system: 60.00% (n = 42) of nurses considered the system to be helpful for their work and nearly half of the nurses (47.14%, n = 33) believed that the system could facilitate clinical work and reduce workload; 51.43% (n = 36) believed that the system could reduce checking time and enhance work efficiency; 82.86% (n = 58) believed that the system was helpful in improving checking accuracy to reduce MAEs and ensure patient safety. More than 60% of the nurses considered the system to be a method that could help to track MAEs to improve nursing quality. (c) The MAE alert logs during observation period: it revealed only 27 alerts from the repeated scans of 3,428 instances of medication administration.

Conclusions

The nurses were satisfied with the closed-loop medication administration system because it improved their work efficiency and reduced their workload. The current investigation was limited by time; therefore, further research is needed to more closely examine the relationship between the system and MAEs.

Open access
NPS2390, a selective calcium-sensing receptor antagonist controls the phenotypic modulation of hypoxic human pulmonary arterial smooth muscle cells by regulating autophagy

Abstract

Background and Objectives

Calcium-sensing receptor (CaSR) is known to regulate hypoxia-induced pulmonary hypertension (HPH) and vascular remodeling via the phenotypic modulation of pulmonary arterial smooth muscle cells (PASMCs) in small pulmonary arteries. Moreover, autophagy is an essential modulator of VSMC phenotype. But it is not clear whether CaSR can regulate autophagy involving the phenotypic modulation under hypoxia.

Methods

The viability of human PASMCs was detected by cell cycle and BrdU. The expressions of proliferation protein, phenotypic marker protein, and autophagy protein in human PASMCs were determined by western blot.

Results

Our results showed that hypoxia-induced autophagy was considerable at 24 h. The addition of NPS2390 decreased the expression of autophagy protein and synthetic phenotype marker protein osteopontin and increased the expression of contractile phenotype marker protein SMA-ɑ and calponin via suppressing downstream PI3K/Akt/mTOR signal pathways.

Conclusions

Our study demonstrates that treatment of NPS2390 was conducive to inhibit the proliferation and reverse phenotypic modulation of PASMCs by regulating autophagy levels.

Open access
The Prevalence and Levels of Anti-HEV IgG in the Population of Jiangsu Province, China

Objective To investigate the prevalence and levels of anti-HEV IgG in the population of Jiangsu Province.

Methods Total of 2 656 samples from Qindong and 11 463 samples from Anfeng were colleted. The anti- HEV antibody was qualitatively and quantitatively detected using ELISA kits and the references had been established.

Results The positive rates of anti-HEV IgG in male and female were 55.6% and 40.1%, respectively. The positive rate of anti-HEV IgM in male and female were both 3.4%. In opposite to anti-HEV IgG, the positive rate of anti-HEV IgM in Anfeng was significant higher than that in Qindong. The mean anti-HEV IgG titers for 6 age groups were 0.94, 0.92, 1.07, 1.46, 1.27, 1.19 and 0.68, 1.31, 1.08, 1.14, 1.31, 1.68 IU/ml, in Qindong and Anfeng region, respectively. The positive rate of anti-HEV IgG tended to increase with age and the titer of anti- HEV IgG was associated with age (R > 0.90).

Conclusions The results in this study showed that HEV was widely prevalent in both Qindong and Anfeng of Jiansu Province and the prevalence and the anti-HEV IgG titer were associated with gender and age.

Open access