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1.
Alan Bivens Rashim Gupta Ingo McLean Boleslaw Szymanski Jerome White 《International Journal of Network Management》2004,14(2):131-146
Rapid growth of computer network sizes and uses necessitate analysis of network application middleware in terms of its scalability as well as performance. In this paper we analyze a distributed network management middleware based on agents that can be dispatched to locations where they can execute close to the managed nodes. The described middleware operates between the network protocol layer and the application layer and uses standard TCP protocol and SNMP probes to interface the network. By aggregating requests from many users into a single agent, our system allows multiple managers to probe problem areas with minimal management traffic overhead. We discuss and quantify the benefits of the described middleware by implementing real‐time network managers using our system. The main result of this paper is a comparison of scalability and efficiency of our agent‐based management middleware and traditional SNMP‐based data collection. To this end, we measured traffic in both real and simulated networks. In the latter case, we designed, used and described here a method of separating simulated application flow into separate subflows to simplify design of simulations. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
2.
Peter Fleischmann Ingo Janiszczak 《Applicable Algebra in Engineering, Communication and Computing》1996,7(3):221-234
In this paper an algorithm is presented to determine the number of semisimple conjugacy classes for a given centralizertype for the Chevalley groupsSL
n(q) andSU
n(q). Moreover we give the exact number of regular semisimple classes of this groups and a summary of results on the generic classnumber of exceptional Chevalley groups of adjoint type.The first author acknowledges financial support by a grant of the Deutsche Forschungsgemeinschaft 相似文献
3.
Prof. Dr.-Ing. Hans-Joachim Franke Dipl.-Ing. Ingo Kaletka 《Forschung im Ingenieurwesen》1996,62(10):265-270
Zusammenfassung Ziel des Teilvorhabens, über das hier berichtet wird, was es, für eine Auswahl von physikalischen Effekten eine Zuordnung
von gestaltbeeinflussenden Merkmalen auf sehr abstrakter Ebene zu erreichen und damit eine n?here Charakterisierung der Wirkfl?chen
und Wirkr?ume zu erreichen die zur Umsetzung eines physikalischen Effektes notwendig sind. Die hieraus resultierenden Ergebnisse
sind dem Abschlu?bericht zu entnehmen [1]. Weiterführende Themen, die basierend auf den vorliegenden Erkenntnissen bearbeitet
werden, haben zum Ziel, die wesentlichen und entscheidenden Parameter einer Konstruktionsaufgabe zu erkennen und zukünftig
zielgerichtet L?sungsvarianten zu erstellen, um somit für eine Neukonstruktion sinnvolle L?sungsfelder sehr frühzeitig abzugrenzen. 相似文献
4.
Many real-world problems are multi-objective optimization problems and evolutionary algorithms are quite successful on such problems. Since the task is to compute or approximate the Pareto front, multi-objective optimization problems are considered as more difficult than single-objective problems. One should not forget that the fitness vector with respect to more than one objective contains more information that in principle can direct the search of evolutionary algorithms. Therefore, it is possible that a single-objective problem can be solved more efficiently via a generalized multi-objective model of the problem. That this is indeed the case is proved by investigating the computation of minimum spanning trees.This work was supported by the Deutsche Forschungsgemeinschaft (DFG) as part of the Collaborative Research Center Computational Intelligence (SFB 531) and by the German-Israeli Foundation (GIF) in the project Robustness Aspects of Algorithms. 相似文献
5.
6.
Ingo Alig Dirk Lellinger Harald Oehler Sergey A. Adamovsky Christoph Schick 《Progress in Organic Coatings》2008,61(2-4):166-175
A new microcalorimeter with eight parallel channels using robust, low cost sensors for characterization of coatings and adhesives is described and first experiments on coatings and adhesives are presented. The calorimetric sensors are based on thin glass plates (20 mm × 20 mm, thickness 150 μm) with heater and thermocouple sputtered on the surfaces (calorimetric active area of about 9 mm2). The setup allows heating and cooling experiments as well as isothermal measurements in the temperature-modulated mode with up to eight sensors in parallel. The measured quantities are the real (C′p) and imaginary part (C″p) of the complex heat capacity (), the related absolute value of the heat capacity () and the heat flow . An industrial computer (NI PXI system) with specific software for calibration and data recording controls the electronic components. Sensors can be embedded in a temperature controlled oven (heating and cooling by Peltier elements) or alternatively in a climatic cabinet with controlled temperature and humidity.
The method has been applied successfully to monitoring of film formation of aqueous polymer dispersions (styrene-acrylate copolymer) and curing of coatings. 相似文献
7.
B Pfaffenbach RJ Adamek D Hagemann S Busch K Hoffmann P Altmeyer J Schaffstein M Wegener 《Canadian Metallurgical Quarterly》1996,34(9):517-521
In patients with progressive systemic sclerosis (PSS) suffering from chronic dyspepsia the stomach may be affected by this disease. The objective of this study was to investigate both antral myoelectrical activity and gastric emptying in PSS patients. Electrogastrography (EGG) was performed in 17 PSS patients (16 female, one male, median age 58 years, range 32-74 years) with chronic dyspepsia. After an overnight fast during one hour in the fasting and one hour in the fed state after ingestion of a liquid-solid test meal (370 kcal; liquid phase labeled with 0.5 mCi 99mTc-colloid) antral electrical activity was measured by one pair of electrodes sonographically placed on the skin overlying the gastric antrum. Several EGG parameters including dominant frequency (DF), percentages of DF in the normal range (2-4 cycles per minute [cpm]), bradygastria (< 2 cpm) and tachygastria (4-10 cpm), dominant frequency instability coefficient (DFIC), and postprandial to preprandial power ratio (PR) were calculated. The data were correlated to results obtained in 20 age- and gender-matched healthy subjects. In addition, the data were compared to gastric retention of the radionuclide at 60 min measured by simultaneous scintigraphy. The PSS patients did not reveal electrical disturbances. They even exhibited a significant postprandial decrease in DFIC, bradygastria, and tachygastria (ns) compared to healthy subjects. Over 50% of the PSS patients showed a delayed gastric emptying. However, EGG did not correlate to radioscintigraphy significantly. Our results reflect an absent relationship between antral myoelectrical activity in EGG and gastric emptying. Therefore, electrogastrography is unsuitable to assess gastric involvement in PSS. 相似文献
8.
Cure of Helicobacter pylori infection: role of duration of treatment with omeprazole and amoxicillin
A case of ankylosing spondylitis with pronounced osteolysis of the 12th thoracic vertebral body as part of posttraumatic pseudoarthrosis is described. The appearance of posttraumatic osteolysis simulates a malignant lesion, and it is important to consider the diagnosis in cases of osteolytic lesions of unknown origin. 相似文献
9.
XPS investigation on AISI 420 stainless steel corrosion in oil and gas well environments 总被引:3,自引:0,他引:3
G. Fierro G. M. Ingo F. Mancia L. Scoppio N. Zacchetti 《Journal of Materials Science》1990,25(2):1407-1415
The corrosion behaviour of 13Cr-martensitic stainless steel (AISI 420) was investigated in CO2-H2S-Cl– environments typical of oil and gas wells under different CO2 and H2S partial pressures. The corrosion tests indicated that the AISI 420 steel was highly corrosion resistant to CO2-induced phenomena (general corrosion and carbonate S.C.C.), while in the H2S environment a high S.S.C.C. (Sulphide Stress Corrosion Cracking) susceptibility and high corrosion rates were found. Moreover, CO2 in CO2-H2S-Cl– systems inhibited general corrosion and S.S.C.C. phenomena by favouring the formation of a protective film. By means of X-ray photoelectron spectroscopy (XPS) the chemical nature of the films grown on AISI 420 in different environmental conditions was investigated and the following statements were drawn out:
Furthermore from XPS results an index of protectivenessI
p = Cr+3/ (Cr+3 + Fe
OX
was defined and related to the environmental parameter
and to the corrosion rates. 相似文献
| CO2 favours the growth of a hydrated Cr-oxide rich protective film with a low Fe-oxide and sulphide content; |
| the presence of H2S favours the formation of less protective Fe-sulphide and Fe-oxide rich layers. |
10.
Brillouin scattering (BS), photon correlation spectroscopy (PCS), and ultrasonic (US) measurements were conducted to study the curing process of diglycidyl ether of bisphenol A with butane-1,4-diol at a curing temperature of 100°C. The experimental techniques probe the primary glass-rubber transition during the curing reaction. The primary relaxation time τ obtained from the BS and US velocity and absorption increases with curing time and hence the BS experiment measures τ at earlier stages of cure than the US experiment. The relaxation times at a different extent of reaction and for different measuring temperatures are consistent with BS, US, PCS, and DSC measurements and conform to a single reduced Vogel–Fulcher–Hesse–Tamann equation. Furthermore, the US experiments show evidence of secondary relaxations in the epoxy system. 相似文献