Use of upper bound delay estimate in stability analysis and robust control compensation in networked control systems

Recent interest in networked control systems (NCS) has instigated research in various areas of both communication networks and control. The analysis of NCS has often been performed either from the network, or the control point of view and not many papers exist were the analysis of both is done in the same context. Here a simple overall analysis is presented. In the paper the procedure of obtaining the upper bound delay value in the switched Ethernet network is proposed and the obtained delay estimate is used in stability analysis of the feedback loop and in the control compensation. The upper bound delay algorithm is based on the network calculus theory, the stability analysis uses the small gain theorem, and control compensating strategy is based on Smith predictor, where however the upper bound delay is utilised in obtaining the delay estimate.Comment: 6 page

Control compensation based on upper bound delay in networked control systems

Recent interest in networked control systems (NCS) has instigated research in both communication networks and control. Analysis of NCSs has usually been performed from either the network or the control point of view, but not many papers exist where the analysis of both is done in the same context. In this paper an overall analysis of the networked control system is presented. First, the procedure of obtaining the upper bound delay value for packet transmission in the switched Ethernet network is presented. Next, the obtained delay estimate is utilised in delay compensation for improving the Quality of Performance (QoP) of the control systems. The presented upper bound delay algorithm applies ideas from network calculus theory. For the improvement of QoP, two delay compensation strategies, the Smith predictor based and the robust control based delay compensation strategies, are presented and compared.Comment: 6 page

Minimum Cycle Time Analysis of Ethernet-Based Real-Time Protocols

The Ethernet standard is a standard solution for interconnecting industrial devices despite its intrinsic drawbacks, particularly its nondeterministic medium access method. Many Ethernet-based commercial solutions available (COTS - Components Off the Shelves) on the market guarantee time performance. This means that user selection of one particular solution is a critical decision, but the choice often depends more on political strategizing with an industrial device manufacturer than on the intrinsic performance of Ethernet-based interfaces. The objective of this paper is to provide a formal behavioural analysis of each Ethernet-based solution, in order to facilitate comparison

Multicenter trial of one HLA-DR–matched or mismatched blood transfusion prior to cadaveric renal transplantation

Multicenter trial of one HLA-DR–matched or mismatched blood transfusion prior to cadaveric renal transplantation.BackgroundThe beneficial effect of blood transfusions before cadaveric renal transplantation on allograft survival, although previously well documented, has become controversial in light of their adverse effects. Recently, it has been suggested that their clinical benefits are due to HLA-DR sharing between the blood donor and recipient.MethodsIn this prospective study, 144 naive patients were randomly assigned to receive one unit of blood matched for one-HLA-DR antigen (N = 49), or one unit of mismatched blood (N = 48), or to remain untransfused (N = 47). Graft survival and acute rejection rate were analyzed in 106 cadaveric renal allograft recipients receiving the same immunosuppressive protocol.ResultsGraft survival was similar in the three groups at one and five years: 91.7 and 80% in untransfused patients, 90.3 and 79.3% in patients transfused with one DR-antigen–matched unit, and 92.3 and 83.7% in patients transfused with HLA-mismatched blood. The difference in the incidence of six-month post-transplant acute rejections was not statistically significant in the three groups: 12 out of 36, 33.3% in nontransfused patients; 6 out of 31, 19.4% in patients transfused with one DR-matched blood; and 13 out of 39, 33.3% in patients transfused with mismatched blood.ConclusionThe results of our prospective randomized trial showed that in a population of naive patients, one transfusion mismatched or matched for one HLA-DR antigen given prior to renal transplantation had no significant effect on the incidence and severity of acute rejection, and did not influence overall long-term graft outcome. Considering the potentially deleterious adverse effects of blood transfusions, the costs, and the considerable logistical efforts required to select and type blood donors, such a procedure cannot be recommended in a routine practice for patients awaiting cadaveric kidney transplantation

L'application de la loi du 31 décembre 1989 par les tribunaux d'instance: l'exemple de cinq tribunaux de la région Rhône-Alpes

Etude consacrée au second volet contenu dans le titre premier de la loi n° 89-1010 du 31 décembre 1989 intitulée "loi relative à la prévention et au règlement des difficultés liées au surendettement des particuliers et des familles", qui institue deux procédures visant à permettre le redressement de la situation de particuliers "surendettés". La loi de 1989 a été complétée par un décret n° 90-175 du 21 février 1990. Elle a été ultérieurement modifiée par la loi n° 91-650 du 9 juillet 1991qui a transféré les compétences du tribunal d'instance au juge de l'exécution. Le présent rapport retrace les résultats d'une enquête qui a été menée sur l'application de ces textes par cinq tribunaux d'instance de la région Rhône-Alpes (Grenoble, Lyon, Saint-Etienne, Trévoux, Valence), pendant les deux premières années qui ont suivi l'entrée en vigueur de la loi, soit entre le 1er mars 1990 et le 28 février 1992

Signaling pathways involved in LPS induced TNFalpha production in human adipocytes

<p>Abstract</p> <p>Background</p> <p>The development of obesity has been linked to an inflammatory process, and the role of adipose tissue in the secretion of pro-inflammatory molecules such as IL-6 or TNFalpha has now been largely confirmed. Although TNFalpha secretion by adipose cells is probably induced, most notably by TLR ligands, the activation and secretion pathways of this cytokine are not yet entirely understood. Moreover, given that macrophagic infiltration is a characteristic of obesity, it is difficult to clearly establish the level of involvement of the different cellular types present within the adipose tissue during inflammation.</p> <p>Methods</p> <p>Primary cultures of human adipocytes and human peripheral blood mononuclear cells were used. Cells were treated with a pathogen-associated molecular pattern: LPS, with and without several kinase inhibitors. Western blot for p38 MAP Kinase was performed on cell lysates. TNFalpha mRNA was detected in cells by RT-PCR and TNFalpha protein was detected in supernatants by ELISA assays.</p> <p>Results</p> <p>We show for the first time that the production of TNFalpha in mature human adipocytes is mainly dependent upon two pathways: NFkappaB and p38 MAP Kinase. Moreover, we demonstrate that the PI3Kinase pathway is clearly involved in the first step of the LPS-pathway. Lastly, we show that adipocytes are able to secrete a large amount of TNFalpha compared to macrophages.</p> <p>Conclusion</p> <p>This study clearly demonstrates that the LPS induced activation pathway is an integral part of the inflammatory process linked to obesity, and that adipocytes are responsible for most of the secreted TNFalpha in inflamed adipose tissue, through TLR4 activation.</p