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排序方式: 共有824条查询结果,搜索用时 15 毫秒
51.
Abhishek Dubey Steve Nordstrom Turker Keskinpala Sandeep Neema Ted Bapty Gabor Karsai 《Innovations in Systems and Software Engineering》2007,3(1):33-52
Designing autonomic fault responses is difficult, particularly in large-scale systems, as there is no single ‘perfect’ fault
mitigation response to a given failure. The design of appropriate mitigation actions depend upon the goals and state of the
application and environment. Strict time deadlines in real-time systems further exacerbate this problem. Any autonomic behavior
in such systems must not only be functionally correct but should also conform to properties of liveness, safety and bounded
time responsiveness. This paper details a real-time fault-tolerant framework, which uses a reflex and healing architecture
to provide fault mitigation capabilities for large-scale real-time systems. At the heart of this architecture is a real-time
reflex engine, which has a state-based failure management logic that can respond to both event- and time-based triggers. We
also present a semantic domain for verifying properties of systems, which use this framework of real-time reflex engines.
Lastly, a case study, which examines the details of such an approach, is presented. 相似文献
52.
The paper proposes a hierarchical control design of an electro-hydraulic actuator, which is used to improve the roll stability of vehicles. The purpose of the control system is to generate a reference torque, which is required by the vehicle dynamic control. The control-oriented model of the actuator is formulated in two subsystems. The high-level hydromotor is described in a linear form, while the low-level spool valve is a polynomial system. These subsystems require different control strategies. At the high level, a linear parameter-varying control is used to guarantee performance specifications. At the low level, a control Lyapunov-function-based algorithm, which creates discrete control input values of the valve, is proposed. The interaction between the two subsystems is guaranteed by the spool displacement, which is control input at the high level and must be tracked at the low-level control. The spool displacement has physical constraints, which must also be incorporated into the control design. The robust design of the high-level control incorporates the imprecision of the low-level control as an uncertainty of the system. 相似文献
53.
Hong-Lei Wang Cheng-Hua Zhao Gabor Szöcs Satya Prabhakar Chinta Stefan Schulz Christer Löfstedt 《Journal of chemical ecology》2013,39(6):790-796
The trienoic and tetraenoic polyenes, (3Z,6Z,9Z)-3,6,9-nonadecatriene, (3Z,6Z,9Z)-3,6,9-henicosatriene, and (3Z,6Z,9Z)-1,3,6,9-henicosatetraene were found in the abdominal cuticle and pheromone gland of the winter moth Operophtera brumata L. (Lepidoptera: Geometridae), in addition to the previously identified single component sex pheromone (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene. The pheromone biosynthesis activating neuropeptide (PBAN) is involved in the regulation of polyene transport from abdominal cuticle to the pheromone gland. In vivo deuterium labeling experiments showed that (11Z,14Z,17Z)-11,14,17-icosatrienoic acid, the malonate elongation product of linolenic acid, (9Z,12Z,15Z)-9,12,15-octadecatrienoic acid, is used to produce (3Z,6Z,9Z)-3,6,9-nonadecatriene and (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene. 相似文献
54.
55.
The methods are reviewed for obtaining monolayer epithelium cultures both in normal and hyperplastic or malignant prostate glands. Preparation of pure epithelial tissue cultures is dealt with in detail. The major prostate cell lines are described. Special attention is paid to the markers of differentiation and sensitivity to hormones in normal and tumour prostatic cells in vitro. Prospects for the use of prostatic cell cultures as models in oncology are outlined. 相似文献
56.
For the general calculation of the transformation of steels the transformation diagram for isothermal transformation must be known. It is described, how from dilatometric measurements with continuous cooling the transformation at a constant temperature can be calculated. To do this, the simplex method must be used as iteration process to achieve sufficient precision. Even when measuring data are scattered around an ideal value by ±5% the transformation diagram for isothermal transformation can be calculated with considerable accuracy. 相似文献
57.
58.
N. Armata G. Baldissin G. Barone R. Cortese V. D’Anna F. Ferrante S. Giuffrida G. Li Manni A. Prestianni T. Rubino Zs. Varga D. Duca 《Topics in Catalysis》2009,52(4):431-443
Monte Carlo algorithms and codes, used to study heterogeneous catalytic systems in the frame of the computational section
of the NANOCAT project, are presented along with some exemplifying applications and results. In particular, time dependent
Monte Carlo methods supported by high level quantum chemical information employed in the field of heterogeneous catalysis
are focused. Technical details of the present algorithmic Monte Carlo development as well as possible evolution aimed at a
deeper interrelationship of quantum and stochastic methods are discussed, pointing to two different aspects: the thermal-effect
involvement and the three-dimensional catalytic matrix simulation. As topical applications, (i) the isothermal and isobaric
adsorption of CO on Group 10 metal surfaces, (ii) the hydrogenation on metal supported catalysts of organic substrates in
two-phase and three-phase reactors, and (iii) the isomerization of but-2-ene species in three-dimensional supported and unsupported
zeolite models are presented. 相似文献
59.
Gabor A. Somorjai 《Catalysis Letters》2005,101(1-2):1-3
Catalytic nanodiodes, Pt/TiO2 or Pt/GaN produce continuous flow of hot electron current during carbon monoxide oxidation for hours in the 80–150 °C temperature range at pressures of 100 Torr of O2 and 40 Torr of CO. These observations provide proof of the Schottky diode model of oxide supported metal catalysis of many reactions that have been proposed by Schwab, Solymosi and others since the 1960s. The flow of hot electrons should influence chemistry at oxide–metal interfaces and the metal particle size dependence of catalytic activity and selectivity. 相似文献
60.
J Rigó M Burger I Repa A Vereckei I Varga P Pusztai C Dzsinich 《Canadian Metallurgical Quarterly》1997,138(35):2187-2190
Bilateral renal artery stenosis was diagnosed noninvasively in the 17th gestational week, in a chronically hypertensive pregnant woman, by renal artery duplex ultrasound examination, MRI and MR angiography. Continuous monitoring of the mother and the fetus was performed. Blood pressure was stabilized by complex antihypertensive therapy, but from the beginning of the third trimester superimposed preeclampsia developed gradually. In the 34th gestational week a 1600-g newborn was delivered by elective cesarean section. The case report draws attention to the significance of the thorough examination of hypertensive women before pregnancy. 相似文献