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51.
We investigate a variety of known and new approaches for the estimation of the parameters of discrete-time semi-Markovian
traffic models. We focus on modeling video traffic, since the accurate representation of its long-term autocorrelation is
a challenge to the parameter estimation methods. The modeling techniques are applied to sample H.264/AVC-encoded video traces.
We study their ability to reflect the autocorrelation and variability of the original traffic and also the delay probabilities
of a resulting SMP/GI/1 queueing system. The delay probabilities are determined both by simulation and verified analysis of
the queue. 相似文献
52.
Sandra Fleischer Stefan C. Weiss Thomas Lucke Wolfram Seitz Wolfgang Schulz Walter H. Weber 《臭氧:科学与工程》2015,37(5):441-449
Although oxamic acid has been identified as an ozone oxidation product from several precursor compounds, concentrations for drinking water have not been published previously. This study shows results from a full-scale drinking water treatment plant, noting that the mean concentrations for oxamic acid reached 21.3 μg/L after ozonation and prior to filtration. Subsequent multiple-layer filtration removed 85% of oxamic acid on average, and mean concentrations in drinking water were 2 μg/L. Up to 5.9% of the oxamic acid found in ozone-treated groundwater may be formed from Chloridazon metabolites. 相似文献
53.
George Kornaros Matthias Sund Wolfram Lautenschlaeger Helen-Catherine Leligou Theofanis Orphanoudakis 《AEUE-International Journal of Electronics and Communications》2010,64(1):17-28
Aggregating Ethernet frame or IP packet in large fixed-size frames allows for building scalable core network architectures. Classifying the arriving traffic based on destination core node information and quality of service parameters alleviates the need of performing table look-ups on packet basis. These advantages come at the cost of extra logic at the network egress, as regards implementation, and additional jitter due to the frame assembly process. This paper describes the efficient implementation of a frame aggregation unit that gathers Ethernet packets in G.709 containers, handles 10 Gb/s links, performs classification based on 24-byte headers, and includes a highly pipelined Queue Manager to cope with the considered rates while a specific scheduler controls the quality of service per core network flow. Based on the developed demonstrator, we provide results both as regards area and performance for an FPGA (field programmable gate array) Virtex-4 implementation as well as regarding the introduced jitter. 相似文献
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56.
Kai O. Arras Wolfram Burgard Horst-Michael Gross 《Robotics and Autonomous Systems》2010,58(2):131-132
57.
Martin Beerbom Oliver Henrion Andreas Klein Thomas Mayer Wolfram Jaegermann 《Electrochimica acta》2000,45(28):4663
We have applied photoelectron spectroscopy to investigate the surface composition after different surface treatments involving Br2–H2O mixtures in order to study wet chemical etching. Emersion experiments from Br2–H2O solution are compared with model experiments, in which Br2–H2O adsorbate and coadsorbate mixtures react with clean GaAs(110) surfaces. Our results indicate that Ga- and As-bromides formed initially are hydrolyzed to form the respective oxides. Without addition of Br2, only slight oxidation of the surface takes place. There is an enrichment of Ga due to loss of As both in adsorption as well as in emersion experiments. Since in emersion experiments only a final situation is analyzed, the relative influence of surface reactivity and subsequent solvation effects cannot be distinguished easily, while model experiments give clear information on reaction products formed intermediately. However, model experiments differ in environment and temperature from the real solid–liquid interface. The presented results demonstrate that a combination of emersion and model experiments provide valuable insight into the mechanism of wet chemical etching on a microscopic level. 相似文献
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In the current study the savings of CO2 emissions due to the use of ground source heat pump (GSHP) systems was investigated in comparison to conventional heating systems. Based on a subsidy program for GSHP systems in southwest Germany, the regional, average, and total CO2 savings of 1105 installed GSHP systems were determined on a regional scale. The emitted CO2 per kWh of heating demand for the studied scenario resulted in 149 g CO2/kWh for GSHP using the German electricity mix and 65 g CO2/kWh using the regional electricity mix, which results in CO2 savings of 35% or 72%, respectively. Similar CO2 avoidances of GSHP systems were found in American and European studies ranging between 15% and 77% strongly depending on the supplied energy for the heat pumps and the efficiency of installation. The resulting CO2 savings for one installed GSHP unit in the present study therefore range between 1800 and 4000 kg per year. Nevertheless, the minimum average total annual CO2 savings of all installed GSHP systems due to the subsidy program amounted to 2000 tons per year. The maximum regional avoided additional CO2 emissions are primarily associated with the affluent suburbs of the most densely populated area in the region. In 2006 the total contribution of CO2 savings due to GSHP systems in Germany was only about 3.4% of the total renewable energies. However, continuously rising numbers of installed GSHP units and the increasing use of renewable electricity demonstrate that there is a fine opportunity to substantially avoid additional CO2 emissions associated with the provision of heating (and cooling) of buildings and other facilities. 相似文献
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