Search

The existing low-rank graph representation algorithms fail to capture the global representation structure of data accurately, and cannot make full use of the valid information of data to guide the construction of the representation graph, then the constructed representation graph does not have a connected structure suitable for clustering. A smooth non-negative low-rank graph representation method for clustering (SNLRR) is proposed to solve these problems. To more accurately capture the global representation structure of data, SNLRR uses a logarithmic determinant function that is more consistent with the rank characteristics of the matrix to replace the kernel norm to estimate the rank function smoothly, which can effectively reduce the impact of larger singular values of the matrix on the rank estimation, balance the contribution of all singular values to the rank estimation, enhance the accuracy of the rank estimation, so as to more accurately capture the global representation structure of the data. The distance regularization term is also introduced to adaptively assign the optimal nearest neighbor learning representation matrix for each data point to capture the local representation structure of data. Besides, SNLRR applies rank constraint on the Laplace matrix of representation matrix so that the learned representation graph has the same number of connected components as the real number of clusters, that is, the resulting representation graph has a interconnected structure suitable for clustering. Experimental results on seven datasets with high dimensions and complex distribution, using eight comparison algorithms, show that the clustering performance of SNLRR algorithm is better than that of the eight comparison algorithms, with an average increase of 0.2073 in accuracy and 0.1758 in NMI. Therefore, SNLRR is a graph representation clustering algorithm that can effectively handle data with high dimensions and complex distribution.

A feasible method in evaluating the protection effect and corrosion state of marine cathodic protection (CP) systems is collecting sufficient electric potential data around a submarine pipeline and then establishing the mapping relations between these data and corrosion states of pipelines. However, it is difficult for scientists and researchers to obtain those data accurately due to the harsh marine environments and absence of dedicated potential measurement device. In this paper, to alleviate these two problems, firstly, the theory of dimension and conductivity scaling (DACS) physical scale modeling of marine impressed current cathodic protection (ICCP) systems is generalized to marine CP systems, secondly, a potential measurement device is developed specially and analogue experiment is designed according to DACS physical scale modeling to verify the feasibility of the measuring system. The experimental results show that 92 percent of the measurement errors are less than 0.25mv, thereby providing an economical and feasible measuring system to get electric potential data around an actual submarine pipeline under CP.

To monitoring the subsea pipeline in real-time, a special potentiometric sensor array and a potential prediction model are presented in this paper. Firstly, to measure the potential of seawater, a special potentiometric sensor array with Ag/AgCl all-solid-state reference electrodes is first developed in this paper. Secondly, according to the obtained distribution law of electric field intensities a prediction model of the pipeline potentials is developed. Finally, the potentiometric sensor array is applied in sink experiment and the prediction model is validated by the sink measurements. The maximum error for pipeline potential prediction model is 1.1 mV. The proposed non-contact monitoring method for subsea pipeline can predict the potential of sea pipeline in real-time, thus providing important information for further subsea pipeline maintenance.

In this article, a chitosan-based bio-gel electric actuator with tannic acid and carboxymethyl cellulose (CMC)as cross-linked materials was fabricated. By evaluating the output force and electrochemical characteristics of the electric actuator under different doping amounts of tannic acid and CMC, it was found that the sample with appropriate amount of cross-linking can improve its output force, service life, specific capacitance. Infrared spectroscopy, scanning electron microscopy(SEM), and ion channel test showed that tannic acid and CMC were uniformly distributed in the chitosan matrix. The proper crosslinking was beneficial to transform the internal dense and uniform structure into a loose and porous structure, promote the migration of ions, improve the electrochemical performance of the electric actuator, and thereby improve its output performance. This study provided a facile and eco-friendly method to construct chitosan-based electromotive membrane with enhanced output properties. KEYWORDS carboxymethyl cellulose, chitosan, electric actuator, tannic acid, 1 | INTRODUCTION Extensive researches have been carried out on the actuatable materials made of bio-gel materials. As one of these actuatable materials, electric actuators are widely used in soft [...]

It is essential to reduce carbon emissions in wastewater treatment plants (WWTPs) to achieve carbon neutrality in society. However, current optimization of WWTPs prioritizes the operation cost index (OCI) and effluent quality index (EQI) over greenhouse gas (GHG) emissions. This study aims to conduct a multi-objective optimization of a WWTP, considering GHG emissions, EQI, and OCI. The anaerobic-anoxic-oxic integrated membrane bioreactor (AAO-MBR) process in an actual WWTP was selected as a typical case, tens of thousands of scenarios with combinations of six operational parameters (dissolved oxygen (DO), external carbon resource (ECR), poly aluminum chloride (PAC), internal reflux ratio (IRR), external reflux ratio (ERR), and sludge discharge (SD)) were simulated by GPS-X software (Hydromantics 8.0.1). It was shown that ECR has the greatest impact on optimization objectives. In the optimal scenario, the main parameters of ATDO, MTDO, IRR, and ERR were 0.1 mg/L, 4 mg/L, 50%, and 100%, respectively. The EQI, OCI, and GHG of the best scenario were 0.046 kg/m3, 0.27 ¥/m3, and 0.51 kgCO2/m3, which were 2.1%, 72.2%, and 34.6% better than the current situation of the case WWTP, respectively. This study provides an effective method for realizing low-carbon and economical operation of WWTPs. [ABSTRACT FROM AUTHOR]

The artificial propagation of the endangered Solenaia oleivora, with unknown fish hosts, was performed via in vitro culture with bighead carp, grass carp, common carp, bovine, and rabbit sera. The effects of glochidium density on transformation rates were evaluated, and the development of juveniles that metamorphosed successfully was documented. The control group had a transformation rate of 0 and a contamination rate of 0. No significant differences were found in the transformation and contamination rates of the bighead carp, grass carp, and common carp serum groups, and their transformation rates were significantly higher, and contamination rates were significantly lower than those of the bovine and rabbit serum groups. Moreover, no significant differences were observed in the transformation rates of glochidia (culture density, 2000–5000 glochidia/dish) in contamination-free conditions. Specimen shell length/height increased from 1.08 ± 0.01 on the first day to 3.08 ± 0.29 during the 13th week. On the basis of anterior and posterior growth differences, juvenile growth was divided into the following three phases: the rapid anterior growth period, distinct anterior and posterior idiophase, and rapid posterior growth period. This study not only provides technological support for the artificial propagation of S. oleivora but also lays a foundation for resource recovery. [ABSTRACT FROM AUTHOR]

We proposed a compliant leg configuration that enhances the conventional pantograph design with leaf springs. The following facts characterize the proposed configuration: (1) Due to the use of the pantograph structure, the mass is centralized around the hip joint, reducing the lower leg inertia; (2) Leaf springs are chosen as elastic parts to increase energy efficiency and estimate foot-end contact forces. Compared with coil springs, leaf springs require no guide rails to deploy, and their stiffness can be easily adjusted through shape cutting. Analytical models are introduced to analyze the leg's stiffness and estimate the contact forces only with the deflections of leaf springs. A one-leg robot based on the proposed design is built, and various experiments are conducted. Experiments regarding the stiffness calibration and the contact forces estimation showed an acceptable agreement with the analytical model. Experiments of dropping demonstrate the feasibility of the leg to perform spring-like behaviors. Experiments of periodic hopping demonstrate the feasibility of using spring deflections to detect touch-down events. For energy efficiency, it is also observed that the elastic leg has a 20% increment concerning the jumping height in the flight phase, compared with the one where leaf springs are replaced with rigid materials. [ABSTRACT FROM AUTHOR]

A multi-patch HIV/AIDS model with heterosexual transmission is formulated to investigate the impact of population migration on the spread of HIV/AIDS. We derive the basic reproduction number $ R_{0} $ R 0 and prove that if $ R_{0} \lt 1 $ R 0 < 1 , the disease-free equilibrium is globally asymptotically stable. If $ R_{0} \gt 1 $ R 0 > 1 and certain conditions are satisfied, the endemic equilibrium is globally asymptotically stable. We apply the model to two patches and conduct numerical simulations. If HIV/AIDS becomes extinct in each patch when two patches are isolated, the disease remains extinct in two patches when the population migration occurs; if HIV/AIDS spreads in each patch when two patches are isolated, the disease remains persistent in two patches when the population migration occurs; if the disease disappears in one patch and spreads in the other patch when they are isolated, the disease can spread or disappear in two patches if migration rates of individuals are suitably chosen. [ABSTRACT FROM AUTHOR]