Online support vector machine application for model based fault detection and isolation of HVAC system

Abstract—Preventive maintenance plays an important role in Heating, Ventilation and Air Conditioning (HVAC) system. One cost effective strategy is the development of analytic fault detection and isolation (FDI) module by online monitoring the key variables of HAVC systems. This paper investigates realtime FDI for HAVC system by using online Support Vector Machine (SVM), by which we are able to train a FDI system with manageable complexity under real time working conditions. It is also proposed a new approach which allows us to detect unknown faults and updating the classifier by using these previously unknown faults. Based on the proposed approach, a semi unsupervised fault detection methodology has been developed for HVAC system

Human Gingiva-Derived Mesenchymal Stromal Cells Attenuate Contact Hypersensitivity via Prostaglandin E2- Dependent Mechanisms

The immunomodulatory and anti-inflammatory functions of mesenchymal stromal cells (MSCs) have been demonstrated in several autoimmune/inflammatory disease models, but their contribution to the mitigation of contact hypersensitivity (CHS) remains unclear. Here, we report a new immunological approach using human gingiva-derived MSCs (GMSCs) to desensitize and suppress CHS and the underlying mechanisms. Our results showed that systemic infusion of GMSCs before the sensitization and challenge phase dramatically suppress CHS, manifested as a decreased infiltration of dendritic cells (DCs), CD8 + T cells, T H-17 and mast cells (MCs), a suppression of a variety of inflammatory cytokines, and a reciprocal increased infiltration of regulatory T cells and expression of IL-10 at the regional lymph nodes and the allergic contact areas. The GMSC-mediated immunosuppressive effects and mitigation of CHS were significantly abrogated on pretreatment with indomethacin, an inhibitor of cyclooxygenases. Under coculture condition of direct cell-cell contact or via transwell system, GMSCs were capable of direct suppression of differentiation of DCs and phorbol 12-myristate 13-acetate-stimulated activation of MCs, whereas the inhibitory effects were attenuated by indomethacin. Mechanistically, GMSC-induced blockage of de novo synthesis of proinflammatory cytokines by MCs is mediated partly by the tumor necrosis factor-alpha/prostaglandin E 2 (PGE 2) feedback axis. These results demonstrate that GMSCs are capable of desensitizing allergic contact dermatitis via PGE 2-dependent mechanisms. © AlphaMed Press

Cholesterol loading suppresses the atheroinflammatory gene polarization of human macrophages induced by colony stimulating factors

In atherosclerotic lesions, blood-derived monocytes differentiate into distinct macrophage subpopulations, and further into cholesterol-filled foam cells under a complex milieu of cytokines, which also contains macrophage-colony stimulating factor (M-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF). Here we generated human macrophages in the presence of either M-CSF or GM-CSF to obtain M-MO and GM-MO, respectively. The macrophages were converted into cholesterol-loaded foam cells by incubating them with acetyl-LDL, and their atheroinflammatory gene expression profiles were then assessed. Compared with GM-MO, the M-MO expressed higher levels of CD36, SRA1, and ACAT1, and also exhibited a greater ability to take up acetyl-LDL, esterify cholesterol, and become converted to foam cells. M-MO foam cells expressed higher levels of ABCA1 and ABCG1, and, correspondingly, exhibited higher rates of cholesterol efflux to apoA-I and HDL2. Cholesterol loading of M-MO strongly suppressed the high baseline expression of CCL2, whereas in GM-MO the low baseline expression CCL2 remained unchanged during cholesterol loading. The expression of TNFA, IL1B, and CXCL8 were reduced in LPS-activated macrophage foam cells of either subtype. In summary, cholesterol loading converged the CSF-dependent expression of key genes related to intracellular cholesterol balance and inflammation. These findings suggest that transformation of CSF-polarized macrophages into foam cells may reduce their atheroinflammatory potential in atherogenesis.Peer reviewe

Dynamic modelling of heart rate response under different exercise intensity.

Heart rate is one of the major indications of human cardiovascular response to exercises. This study investigates human heart rate response dynamics to moderate exercise. A healthy male subject has been asked to walk on a motorised treadmill under a predefined exercise protocol. ECG, body movements, and oxygen saturation (SpO2) have been reliably monitored and recorded by using non-invasive portable sensors. To reduce heart rate variation caused by the influence of various internal or external factors, the designed step response protocol has been repeated three times. Experimental results show that both steady state gain and time constant of heart rate response are not invariant when walking speed is faster than 3 miles/hour, and time constant of offset exercise is noticeably longer than that of onset exercise

Instabilities of infinite matter with effective Skyrme-type interactions

The stability of the equation of state predicted by Skyrme-type interactions is examined. We consider simultaneously symmetric nuclear matter and pure neutron matter. The stability is defined by the inequalities that the Landau parameters must satisfy simultaneously. A systematic study is carried out to define interaction parameter domains where the inequalities are fulfilled. It is found that there is always a critical density $\rho_{cr}$ beyond which the system becomes unstable. The results indicate in which parameter regions one can find effective forces to describe correctly finite nuclei and give at the same time a stable equation of state up to densities of 3-4 times the saturation density of symmetric nuclear matter.Comment: 20 pages, 5 figures, submitted to Phys.Rev.

Competition of ferromagnetic and antiferromagnetic spin ordering in nuclear matter

In the framework of a Fermi liquid theory it is considered the possibility of ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of ferromagnetic and antiferromagnetic spin polarization parameters as functions of density is found for SkM$^*$, SGII effective forces. It is shown that in the density domain, where both type of solutions of self--consistent equations exist, ferromagnetic spin state is more preferable than antiferromagnetic one.Comment: 9p., 3 figure

A comparative technical and economic analysis of different processes for shale gas conversion to high value products

Natural gas is a clean fuel and proper feed for chemical industries. However, its transportation to consumer markets is harder and more expensive than that of crude oil because of some specific properties. Therefore, natural gas conversion to chemicals and exporting them instead of gas is safer, and this is also more profitable. Up until now, many methods and alternative techniques have been presented in this field. In this study, three important processes of shale gas conversion to more valuable compounds including gas to liquid (GTL), gas to methanol (GTM), and gas to ethylene (GTE) have been simulated by Aspen HYSYS software. Then the economic parameters of each process have been calculated. Eventually, the initial investment costs for GTM, GTL, and GTE are 422, 249, and 967, respectively. Incommands allowed only within braces addition, the return on investment values for GTM, GTL, and GTE have been estimated as 40, 37, and 20%, respectively

A comparative technical and economic analysis of different processes for shale gas conversion to high value products

Natural gas is a clean fuel and proper feed for chemical industries. However, its transportation to consumer markets is harder and more expensive than that of crude oil because of some specific properties. Therefore, natural gas conversion to chemicals and exporting them instead of gas is safer, and this is also more profitable. Up until now, many methods and alternative techniques have been presented in this field. In this study, three important processes of shale gas conversion to more valuable compounds including gas to liquid (GTL), gas to methanol (GTM), and gas to ethylene (GTE) have been simulated by Aspen HYSYS software. Then the economic parameters of each process have been calculated. Eventually, the initial investment costs for GTM, GTL, and GTE are 422, 249, and 967, respectively. Incommands allowed only within braces addition, the return on investment values for GTM, GTL, and GTE have been estimated as 40, 37, and 20%, respectively