180 research outputs found

    A negotiation approach to support interoperability in a collaborative manufacturing environment

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    Maintaining the interoperability in a dynamic competitive manufacturing environment in which different business enterprises collaborate is difficult to achieve. Our approach highlights negotiation as the best solution to solve interoperability problems by reaching the common decision suitable for all managers of various enterprises in the most optimized amount of time. In this context, this paper proposes a multi-agent negotiation model, able to coordinate several negotiations taking place in parallel among multiple participants. It is described the negotiation strategy for evaluating and generating offers and the protocol for sending the offers to the other agents. This model is being implemented in the H2020 C2NET project for supporting manufacturing.info:eu-repo/semantics/acceptedVersio

    Coordinating negotiations in data-intensive collaborative working environments using an agent-based model-driven platform

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    This paper tackles the interoperability problems of enterprise information systems by presenting a distributive model-driven platform for parallel coordination of multiple negotiations in data-intensive collaborative working environments. The proposed model was validated and verified by an industrial application scenario within the European research project H2020 C2NET (Cloud Collaborative Manufacturing Networks). This real scenario developed data-intensive collaborative and cloud-enabled tools that allow the optimisation of the supply network of manufacturing SMEs, proposing a negotiation solution based on a model-driven interoperable decentralised architecture.info:eu-repo/semantics/acceptedVersio

    Carbapenem Resistance in Klebsiella pneumoniae Not Detected by Automated Susceptibility Testing

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    Detecting ÎČ-lactamase–mediated carbapenem resistance among Klebsiella pneumoniae isolates and other Enterobacteriaceae is an emerging problem. In this study, 15 blaKPC-positive Klebsiella pneumoniae that showed discrepant results for imipenem and meropenem from 4 New York City hospitals were characterized by isoelectric focusing; broth microdilution (BMD); disk diffusion (DD); and MicroScan, Phoenix, Sensititre, VITEK, and VITEK 2 automated systems. All 15 isolates were either intermediate or resistant to imipenem and meropenem by BMD; 1 was susceptible to imipenem by DD. MicroScan and Phoenix reported 1 (6.7%) and 2 (13.3%) isolates, respectively, as imipenem susceptible. VITEK and VITEK 2 reported 10 (67%) and 5 (33%) isolates, respectively, as imipenem susceptible. By Sensititre, 13 (87%) isolates were susceptible to imipenem, and 12 (80%) were susceptible to meropenem. The VITEK 2 Advanced Expert System changed 2 imipenem MIC results from >16 ÎŒg/mL to <2 ÎŒg/mL but kept the interpretation as resistant. The recognition of carbapenem-resistant K. pneumoniae continues to challenge automated susceptibility systems

    Highly site-specific H2 adsorption on vicinal Si(001) surfaces

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    Experimental and theoretical results for the dissociative adsorption of H_2 on vicinal Si(001) surfaces are presented. Using optical second-harmonic generation, sticking probabilities at the step sites are found to exceed those on the terraces by up to six orders of magnitude. Density functional theory calculations indicate the presence of direct adsorption pathways for monohydride formation but with a dramatically lowered barrier for step adsorption due to an efficient rehybridization of dangling orbitals.Comment: 5 pages, 4 figures, submitted to Phys. Rev. Lett. (1998). Other related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

    Density-functional study of hydrogen chemisorption on vicinal Si(001) surfaces

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    Relaxed atomic geometries and chemisorption energies have been calculated for the dissociative adsorption of molecular hydrogen on vicinal Si(001) surfaces. We employ density-functional theory, together with a pseudopotential for Si, and apply the generalized gradient approximation by Perdew and Wang to the exchange-correlation functional. We find the double-atomic-height rebonded D_B step, which is known to be stable on the clean surface, to remain stable on partially hydrogen-covered surfaces. The H atoms preferentially bind to the Si atoms at the rebonded step edge, with a chemisorption energy difference with respect to the terrace sites of >sim 0.1 eV. A surface with rebonded single atomic height S_A and S_B steps gives very similar results. The interaction between H-Si-Si-H mono-hydride units is shown to be unimportant for the calculation of the step-edge hydrogen-occupation. Our results confirm the interpretation and results of the recent H_2 adsorption experiments on vicinal Si surfaces by Raschke and Hoefer described in the preceding paper.Comment: 13 pages, 8 figures, submitted to Phys. Rev. B. Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

    DC-electric-field-induced and low-frequency electromodulation second-harmonic generation spectroscopy of Si(001)-SiO2_2 interfaces

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    The mechanism of DC-Electric-Field-Induced Second-Harmonic (EFISH) generation at weakly nonlinear buried Si(001)-SiO2_2 interfaces is studied experimentally in planar Si(001)-SiO2_2-Cr MOS structures by optical second-harmonic generation (SHG) spectroscopy with a tunable Ti:sapphire femtosecond laser. The spectral dependence of the EFISH contribution near the direct two-photon E1E_1 transition of silicon is extracted. A systematic phenomenological model of the EFISH phenomenon, including a detailed description of the space charge region (SCR) at the semiconductor-dielectric interface in accumulation, depletion, and inversion regimes, has been developed. The influence of surface quantization effects, interface states, charge traps in the oxide layer, doping concentration and oxide thickness on nonlocal screening of the DC-electric field and on breaking of inversion symmetry in the SCR is considered. The model describes EFISH generation in the SCR using a Green function formalism which takes into account all retardation and absorption effects of the fundamental and second harmonic (SH) waves, optical interference between field-dependent and field-independent contributions to the SH field and multiple reflection interference in the SiO2_2 layer. Good agreement between the phenomenological model and our recent and new EFISH spectroscopic results is demonstrated. Finally, low-frequency electromodulated EFISH is demonstrated as a useful differential spectroscopic technique for studies of the Si-SiO2_2 interface in silicon-based MOS structures.Comment: 31 pages, 14 figures, 1 table, figures are also available at http://kali.ilc.msu.su/articles/50/efish.ht

    Non-operative management of the sigmoid volvulus – case presentation

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    Sigmoid volvulus happens when the sigmoid wraps around itself and its mesentery. Sigmoid volvulus accounts for 2% to 50% of all colonic obstructions. This pathology generally affects adults, and it is more common in males. The etiology is multifactorial and controversial; the main symptoms are diffuse abdominal pain, distention and constipation, while the pregnant signs are abdominal distention and tenderness. Laboratory findings are not pathognomonic: abdominal X-ray radiographs show a dilated sigmoid colon and multiple intestinal air-fluid levels, abdominal CT and MRI demonstrate a whirled sigmoid mesentery. Flexible endoscopy reveals a spiral sphincter-like twist of the mucosa. The diagnosis of sigmoid volvulus is established by clinical, radiological, endoscopic, and sometimes operative findings. Although flexible endoscopic detorsion is advocated as the primary treatment choice, emergency surgery is required for patients who present with peritonitis, bowel gangrene, or perforation, or for patients whose non-operative treatment is unsuccessful. Although emergency surgery includes various non-definitive or definitive procedures, resection with primary anastomosis is the most commonly recommended procedure. After a successful non-operative detorsion, elective sigmoid resection and anastomosis is recommended. The overall mortality is 10% to 50%, while the overall morbidity is 6% to 24%
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