A new Stack Autoencoder: Neighbouring Sample Envelope Embedded Stack Autoencoder Ensemble Model

Stack autoencoder (SAE), as a representative deep network, has unique and excellent performance in feature learning, and has received extensive attention from researchers. However, existing deep SAEs focus on original samples without considering the hierarchical structural information between samples. To address this limitation, this paper proposes a new SAE model-neighbouring envelope embedded stack autoencoder ensemble (NE_ESAE). Firstly, the neighbouring sample envelope learning mechanism (NSELM) is proposed for preprocessing of input of SAE. NSELM constructs sample pairs by combining neighbouring samples. Besides, the NSELM constructs a multilayer sample spaces by multilayer iterative mean clustering, which considers the similar samples and generates layers of envelope samples with hierarchical structural information. Second, an embedded stack autoencoder (ESAE) is proposed and trained in each layer of sample space to consider the original samples during training and in the network structure, thereby better finding the relationship between original feature samples and deep feature samples. Third, feature reduction and base classifiers are conducted on the layers of envelope samples respectively, and output classification results of every layer of samples. Finally, the classification results of the layers of envelope sample space are fused through the ensemble mechanism. In the experimental section, the proposed algorithm is validated with over ten representative public datasets. The results show that our method significantly has better performance than existing traditional feature learning methods and the representative deep autoencoders.Comment: 17 pages,6 figure

Minimal Cut Sets-Based Reliability Evaluation of the More Electric Aircraft Power System

The More Electric Aircraft (MEA) stands for the direction of aviation development in the new era, and the reliability of power systems on the MEA has attracted widespread attention. Based on the characteristics of MEA power systems, an equivalent method of electrical topology structure is presented in this article, and evaluation method is proposed which shows the reliability of the overall system with the reliability of specific nodes. Firstly, electrical topology structure of a MEA power system is converted into a network node diagram according to the proposed equivalent method. Then, the minimal path sets of specific nodes are obtained by the adjacent matrix algorithm, and the low-order minimal cut sets of disjointed are obtained. After that, the actual failure rate of components is converted to node failure rate, and the reliability of the overall system is evaluated by operational reliability indexes of specific nodes. Finally, taking the MEA A380 as an example, this paper compares and analyzes the reliability of AC loads, DC loads, and key loads to verify the validity and feasibility of the proposed evaluation method. This evaluation system can predict the weak points existing in the MEA power system, as well as providing theoretical support for maintenance schedule

Litter Decomposition of Qinghai Spruce (Picea crassifolia) Is Dependent on Mn Concentration in the Qilian Mountains, Northwest China

The factors determining litter decomposition incorporated into C and nutrient cycles were examined as part of a broader study investigating the biogeochemical cycle in forest ecosystems. Litter was collected from five altitudes of Qinghai spruce (Picea crassifolia) woodland stands in the Qilian Mountains and placed in litterbags. These litterbags were installed at the crown center (CC) and crown edge (CE) at different altitudes in Qinghai spruce forests during the growing season to study the effect of litter substrate quality on litter decomposition. Results indicate that at varying altitudes in the growing season, the initial mass loss rate and initial decomposition rate of Qinghai spruce litter showed a nonlinear relationship with altitude. The Olson exponential regression equation showed that the decomposition coefficient (k) was the largest at 3050 m (k = 0.709), and the decomposition coefficient (k) was the smallest at 3250 m (k = 0.476). Meanwhile, the initial decomposition rate was highly correlated with initial litter Ca and Mn concentrations. At the CC and CE at different altitudes in the growing season, the initial mass loss rate of CE was significantly higher than that of CC (p < 0.01), and the initial decomposition rate of CE was markedly faster than that of CC (p < 0.01). The Olson exponential regression equation showed that CE’s decomposition coefficients (k) were larger than those of CC. The initial decomposition rate of CE was highly correlated with initial litter C and Mn concentrations. However, the initial decomposition rate at CC was independent of the litter substrate quality. Finally, we realize that litter decomposition in the early stages is not ultimately determined by a single common factor, but rather the result of multiple factors working together in different orders and strengths. The results lay a foundation for understanding the process and mechanism of litter decomposition in the alpine mountain forest ecosystem and further understanding the structure and function of the ecosystem

The immunomodulation of acetylcholinesterase in zhikong scallop Chlamys farreri.

BACKGROUND: Acetycholinesterase (AChE; EC 3.1.1.7) is an essential hydrolytic enzyme in the cholinergic nervous system, which plays an important role during immunomodulation in vertebrates. Though AChEs have been identified in most invertebrates, the knowledge about immunomodulation function of AChE is still quite meagre in invertebrates. METHODOLOGY: A scallop AChE gene was identified from Chlamys farreri (designed as CfAChE), and its open reading frame encoded a polypeptide of 522 amino acids. A signal peptide, an active site triad, the choline binding site and the peripheral anionic sites (PAS) were identified in CfAChE. The recombinant mature polypeptide of CfAChE (rCfAChE) was expressed in Pichia pastoris GS115, and its activity was 71.3±1.3 U mg(-1) to catalyze the hydrolysis of acetylthiocholine iodide. The mRNA transcripts of CfAChE were detected in haemocytes, hepatopancreas, adductor muscle, mantle, gill, kidney and gonad, with the highest expression level in hepatopancreas. The relative expression level of CfAChE mRNA in haemocytes was both up-regulated after LPS (0.5 mg mL(-1)) and human TNF-α (50 ng mL(-1)) stimulations, and it reached the highest level at 12 h (10.4-fold, P<0.05) and 1 h (3.2-fold, P<0.05), respectively. After Dichlorvos (DDVP) (50 mg L(-1)) stimulation, the CfAChE activity in the supernatant of haemolymph decreased significantly from 0.16 U mg(-1) at 0 h to 0.03 U mg(-1) at 3 h, while the expression level of lysozyme in the haemocytes was up-regulated and reached the highest level at 6 h, which was 3.0-fold (P<0.05) of that in the blank group. CONCLUSIONS: The results collectively indicated that CfAChE had the acetylcholine-hydrolyzing activity, which was in line with the potential roles of AChE in the neuroimmune system of vertebrates which may help to re-balance the immune system after immune response

The temporal expression of CfAChE mRNA in haemocytes after TNF-α stimulation for 1, 3, 6, 9 and 12 h.

<p>Data was expressed as the ratio of the CfAChE mRNA to the β-actin mRNA. The relative CfAChE expression level was determined for each group, and the unstimulated scallops (0 h) were used as the blank group, and scallops injected with PBS were used as the control group. Values were shown as mean ± S.E. (N = 6), and bars with * are significantly different (<i>P</i><0.05).</p

Tissue distribution of the CfAChE transcripts detected by SYBR Green RT-PCR.

<p>CfAChE transcript level in adductor muscle, mantle, gill, hepatopancreas, kidney and gonad of six adult scallops was normalized to that of haemocytes. Vertical bars represented the mean ± S.E. (N = 6), and bars with * are significantly different (<i>P</i><0.05).</p

The temporal expression of CfAChE mRNA in haemocytes after LPS stimulation for 3, 6, 12, 24, 48 and 96 h.

<p>Data was expressed as the ratio of the CfAChE mRNA to the β-actin mRNA. The relative CfAChE expression level was determined for each group, and the unstimulated scallops (0 h) were used as the blank group, and scallops injected with PBS were used as the control group. Values were shown as mean ± S.E. (N = 6), and bars with * are significantly different (<i>P</i><0.05).</p

SDS-PAGE analysis of recombinant CfAChE.

<p>After electrophoresis, the gel was visualized by Coomassie brilliant blue R250 staining. Lane 1: purified recombinant CfAChE; Lane 2: protein molecular standard; Lane 3: recombinant CfAChE after deglycosylation by PNGase F; Lane 4: PNGase F as control.</p