Adaptive Control of Nonlinear Discrete-Time Systems by Using OS-ELM Neural Networks

As a kind of novel feedforward neural network with single hidden layer, ELM (extreme learning machine) neural networks are studied for the identification and control of nonlinear dynamic systems. The property of simple structure and fast convergence of ELM can be shown clearly. In this paper, we are interested in adaptive control of nonlinear dynamic plants by using OS-ELM (online sequential extreme learning machine) neural networks. Based on data scope division, the problem that training process of ELM neural network is sensitive to the initial training data is also solved. According to the output range of the controlled plant, the data corresponding to this range will be used to initialize ELM. Furthermore, due to the drawback of conventional adaptive control, when the OS-ELM neural network is used for adaptive control of the system with jumping parameters, the topological structure of the neural network can be adjusted dynamically by using multiple model switching strategy, and an MMAC (multiple model adaptive control) will be used to improve the control performance. Simulation results are included to complement the theoretical results

Parallel Optimization Method of Unstructured-grid Computing in CFD for DomesticHeterogeneous Many-core Architecture

Sunway TaihuLight ranked first in the global supercomputer top 500 list 2016－2018 with a peak performance of 125.4 PFlops.Its computing power is mainly attributed to the domestic SW26010 many-core RISC processor.CFD unstructured-grid computing has always been a challenge for porting and optimizing in domestic many-core supercomputer,because of its complex topology,serious discrete memory access problems,and strongly correlated linear equation solution.In order to give fully play to the computing efficiency of domestic heterogeneous multi-core architecture,firstly,a data reconstruction model is proposed to improve the locality and parallelism of data,and the data structure is more suitable for the characteristics of multi-core architecture.Secondly,aiming at the discrete memory access problem caused by the disorder of unstructured-grid data storage,a discrete memory access optimization method based on prestorage of information relation is proposed,which transforms discrete memory access into continuous memory access.Finally,the pipeline parallelism mechanism in core array is introduced to realize many-core parallelism for solving linear equations with strong correlation.Experiments show that the overall performance of unstructured-grid computing in CFD is improved by more than 4 times,and is 1.2x faster than the general CPU.The computing cores scale to 624 000,and the parallelism efficiency is maintained at 64.5%

Robust Adaptive Control for Nonlinear Discrete-Time Systems by Using Multiple Models

Back propagation (BP) neural network is used to approximate the dynamic character of nonlinear discrete-time system. Considering the unmodeling dynamics of the system, the weights of neural network are updated by using a dead-zone algorithm and a robust adaptive controller based on the BP neural network is proposed. For the situation that jumping change parameters exist, multiple neural networks with multiple weights are built to cover the uncertainty of parameters, and multiple controllers based on these models are set up. At every sample time, a performance index function based on the identification error will be used to choose the optimal model and the corresponding controller. Different kinds of combinations of fixed model and adaptive model will be used for robust multiple models adaptive control (MMAC). The proof of stability and convergence of MMAC are given, and the significant efficacy of the proposed methods is tested by simulation

LNK suppresses interferon signaling in melanoma.

LNK (SH2B3) is a key negative regulator of JAK-STAT signaling which has been extensively studied in malignant hematopoietic diseases. We found that LNK is significantly elevated in cutaneous melanoma; this elevation is correlated with hyperactive signaling of the RAS-RAF-MEK pathway. Elevated LNK enhances cell growth and survival in adverse conditions. Forced expression of LNK inhibits signaling by interferon-STAT1 and suppresses interferon (IFN) induced cell cycle arrest and cell apoptosis. In contrast, silencing LNK expression by either shRNA or CRISPR-Cas9 potentiates the killing effect of IFN. The IFN-LNK signaling is tightly regulated by a negative feedback mechanism; melanoma cells exposed to IFN upregulate expression of LNK to prevent overactivation of this signaling pathway. Our study reveals an unappreciated function of LNK in melanoma and highlights the critical role of the IFN-STAT1-LNK signaling axis in this potentially devastating disease. LNK may be further explored as a potential therapeutic target for melanoma immunotherapy

The paradoxical patterns of expression of indoleamine 2,3-dioxygenase in colon cancer

<p>Abstract</p> <p>Background</p> <p>One of the putative mechanisms of tumor immune escape is based on the hypothesis that carcinomas actively create an immunosuppressed state via the expression of indoleamine 2,3-dioxygenase (IDO), both in the cancer cells and in the immune cells among the tumor-draining lymph nodes (TDLN). In an attempt to verify this hypothesis, the patterns of expression of IDO in the cancer cells and the immune cells among colon cancers were examined.</p> <p>Methods</p> <p>Seventy-one cases of pathologically-confirmed colon cancer tissues matched with adjacent non-cancerous tissues, lymph node metastases, and TDLN without metastases were collected at the Sun Yat-sen Cancer Center between January 2000 and December 2000. The expression of IDO and Bin1, an IDO regulator, was determined with an immunohistochemical assay. The association between IDO or Bin1 expression and TNM stages and the 5-year survival rate in colon cancer patients was analyzed.</p> <p>Results</p> <p>IDO and Bin1 were detected in the cytoplasm of cancer cells and normal epithelium. In primary colon cancer, the strong expression of IDO existed in 9/71 cases (12.7%), while the strong expression of Bin1 existed in 33/71 cases (46.5%). However, similar staining of IDO and Bin1 existed in the adjacent non-cancerous tissues. Among the 41 cases with primary colon tumor and lymph node metastases, decreased expression of IDO was documented in the lymph node metastases. Furthermore, among the TDLN without metastases, a higher density of IDO⁺cells was documented in 21/60 cases (35%). Both univariate and multivariate analyses revealed that the density of IDO⁺cells in TDLN was an independent prognostic factor. The patients with a higher density of IDO⁺cells in TDLN had a lower 5-year survival rate (37.5%) than the cells with a lower density (73.1%).</p> <p>Conclusion</p> <p>This study demonstrated paradoxical patterns of expression of IDO in colon cancer. The high density IDO⁺cells existed in TDLN and IDO was down-regulated in lymph nodes with metastases, implying that IDO in tumor and immune cells functions differently.</p

The density of macrophages in the invasive front is inversely correlated to liver metastasis in colon cancer

<p>Abstract</p> <p>Background</p> <p>Although an abundance of evidence has indicated that tumor-associated macrophages (TAMs) are associated with a favorable prognosis in patients with colon cancer, it is still unknown how TAMs exert a protective effect. This study examined whether TAMs are involved in hepatic metastasis of colon cancer.</p> <p>Materials and methods</p> <p>One hundred and sixty cases of pathologically-confirmed specimens were obtained from colon carcinoma patients with TNM stage IIIB and IV between January 1997 and July 2004 at the Cancer Center of Sun Yat-Sen University. The density of macrophages in the invasive front (CD68TF_Hotspot) was scored with an immunohistochemical assay. The relationship between the CD68TF_Hotspotand the clinicopathologic parameters, the potential of hepatic metastasis, and the 5-year survival rate were analyzed.</p> <p>Results</p> <p>TAMs were associated with the incidence of hepatic metastasis and the 5-year survival rate in patients with colon cancers. Both univariate and multivariate analyses revealed that the CD68TF_Hotspotwas independently prognostic of survival. A higher 5-year survival rate among patients with stage IIIB after radical resection occurred in patients with a higher macrophage infiltration in the invasive front (81.0%) than in those with a lower macrophage infiltration (48.6%). Most importantly, the CD68TF_Hotspotwas associated with both the potential of hepatic metastasis and the interval between colon resection and the occurrence of hepatic metastasis.</p> <p>Conclusion</p> <p>This study showed evidence that TAMs infiltrated in the invasive front are associated with improvement in both hepatic metastasis and overall survival in colon cancer, implying that TAMs have protective potential in colon cancers and might serve as a novel therapeutic target.</p