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101.
It is quite common to see that classical periodic or Poisson packet traffic models are used for evaluating the performance of wireless sensor networks (WSNs). However, these models may not be appropriate for modeling the data traffic resulting from a particular application. Furthermore, they may be overestimating the performance of a WSN. In this paper, we show the significance of using a realistic and application-specific packet traffic model by comparing the performance of a well-known WSN protocol under the Surveillance WSN packet traffic model (SPTM), as well as under periodic and binomial traffic models. A packet traffic framework specific to surveillance applications is proposed which is then used for deriving SPTM analytically. In order to be adaptable and flexible, SPTM incorporates a probabilistic and parametric sensor detection model. Simulation results show that to employ an application-specific packet traffic model has significant impact on the performance evaluation of the WSN and ordinary traffic models may overestimate the capacity of the WSN. 相似文献
102.
103.
在对风险理论及水资源风险研究进展回顾与展望的基础上,探讨了水资源短缺风险主导因子的辨识方法,提出了采用缺水率、人均缺水量和缺水边际损失3个指标的缺水风险评价指标体系,采用模糊层次分析评价方法对全国二级水资源分区的缺水风险进行了综合评价。评价结果表明,全国现状情况下有33个二级水资源分区面临着不同程度的水资源短缺风险,必须采取工程和非工程等防范措施和有效调控,方可减轻缺水风险对我国经济社会发展的危害程度。 相似文献
104.
A new empirical equation is proposed for predicting critical flow velocity in slurry-transporting horizontal pipelines. An analysis of the settling velocity of solid particles, including the effect of solid particle concentration, is undertaken because of this parameter's importance. This study builds on a previous study carried out to consider the settling velocity of a single solid particle in clear-water condition, which is actually different from the real physics of the hydrotransport phenomenon of the solid particles. Two earlier proposed methods are applied to the calculation of the settling velocity of a solid particle, including the effect of solid particle concentration within the suspending fluid. The most appropriate method for slurry transportation among these two methods is discussed and used in the analysis of critical flow velocity. The new proposed equation is based on analysis of data from the experiments as well as data from the earlier studies. A unique feature of the proposed equation is that it can be applied to noncohesive, uniform, and nonuniform coarse solid particles. In a comparison of prediction accuracy with four existing relationships, the proposed equation was found to give significantly better agreements with the observed data. Therefore, it can be stated that the new equation can safely be used by designers in the problems of slurry transportation. 相似文献
105.
106.
This paper describes formulation of a hand method that can be used to estimate the computed fundamental periods of vibration of building structures in general and steel eccentrically braced frames (EBFs) in particular. The developed method uses the Rayleigh's method as a basis and utilizes the roof drift ratio (RDR) under seismic forces as a parameter. To obtain RDR, more than 4000 EBFs were designed by considering the seismic hazard, number of stories, braced bay width and link length to bay width ratio as prime variables. A model was developed to estimate RDR, which depends on the rigid plastic deformation mechanism for a typical EBF. The method was verified using design data produced as a part of this work as well as data published in literature. The verifications indicate that the proposed formulation is capable of providing acceptable estimates of the computed period. When compared with existing empirical period–height relationships, the proposed formulation offers closer estimates with reduced scatter. The method was further refined to derive new period–height relationships for two different seismicity regions. The accuracy of the relationship for high seismic regions was verified using measured periods of EBF buildings. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
107.
Boehmite/multi-wall carbon nanotube (MWCNT) composite powders were prepared by hydrothermal processing. Starting chemical of aluminum acetate powders (2Al(OH)(C2H3O2)2) and MWCNTs were mixed for the formation of stoichiometric boehmite powders in an attempt to synthesize MWCNT-reinforced boehmite nano-powders via hydrothermal synthesis at 200 °C for 2 h. Kinetically stable suspensions of MWCNT–boehmite composite powders were prepared and subsequently electrophoretic deposition (EPD) was applied to obtain complex shape products in the form of micro-gears. It is shown that the EPD technique is a powerful tool to manufacture small components in a short time. Detail TEM observations also indicated that hydrothermal processing provides an ideal environment to obtain homogeneous mixtures of MWCNT–boehmite powders due to effective surface functionalization of MWCNTs under hydrothermal conditions. 相似文献
108.
Matthias?Hartmann Vasileios??Pantazis Tom?Vander Aa Mladen?Berekovic Christian?Hochberger 《Journal of Signal Processing Systems》2010,60(2):225-237
Due to the increasing demands on efficiency, performance and flexibility reconfigurable computational architectures are very
promising candidates in embedded systems design. Recently coarse-grained reconfigurable array architectures (CGRAs), such
as the ADRES CGRA and its corresponding DRESC compiler are gaining more popularity due to several technological breakthroughs
in this area. We investigate the mapping of two image processing algorithms, Wavelet encoding and decoding, and TIFF compression
on this novel type of array architectures in a systematic way. The results of our experiments show that CGRAs based on ADRES
and its DRESC compiler technology deliver improved performance levels for these two benchmark applications when compared to
results obtained on a state-of-the-art commercial DSP platform, the c64x DSP from Texas Instruments. ADRES/DRESC can beat
its performance by at least 50% in cycle count and the power consumption even drops to 10% of the published numbers of the
c64x DSP. 相似文献
109.
Tuğçe P. Öztürk Onur B. Özdemir Ali Gelir Nahid A. Keshtiban Önder Yargı Selin Pıravadılı Mucur Alper Seçgin 《应用聚合物科学杂志》2024,141(4):e54854
Solid-state electrolytes such a further novel finding is going to have great importance because of the disadvantages of liquid electrolytes such as electrochemical instability, low ion selectivity, and interface contact. It is anticipated that the use of solid-state electrolytes including supercapacitors (SCs) will become widespread with decreasing self-leakage and environmental damage more than liquid electrolytes. In this study, SCs with graphene/PEDOT: PSS coated electrodes and binary PVA gel electrolytes with a conductive layer were designed and the electrochemical performance of the configurations was characterized. The effects of the conductive layer between binary electrolytes and the concentration of the KOH solution in the electrolytes were studied. It was observed that the conductive layer used between the gel electrolytes causes additional charging at the electrolyte/conductive layer interface and behaves like a serially connected capacitor to the double-layer capacitor. Interestingly, at a slow sweep rate (5 mV/s), the specific capacitance values of the assembled SCs decreased when a conductive layer was used but it increased when the sweep rate was fast (100 mV/s). 相似文献
110.
Lactic acid bacteria profiles and tyramine and tryptamine contents of Turkish tulum cheeses 总被引:1,自引:0,他引:1
Zubeyde??nerEmail author Osman?Sa?di? Bedia??im?ek 《European Food Research and Technology》2004,219(5):455-459
Tulum cheese, commonly produced in Turkey, is a traditional Turkish dairy product made from raw milk. In this research, 20 samples of tulum cheese were purchased from different markets in Isparta and Ankara (Turkey) and the populations of lactic acid bacteria (LAB) and contents of biogenic amines of Turkish tulum cheeses were investigated. The mean counts of LAB (as log10 cfu/g) were 7.22±0.67 on MRS agar, 6.93±1.77 on M17 agar, 7.28±0.72 on APT agar and 5.98±2.20 on ADA agar. Isolates of LAB obtained from 20 tulum cheeses were characterised as lactobacilli (48.5%), enterococci (32.7%), lactococci (15.8%) and streptococci (3.0%). Lactobacillus paracasei ssp. paracasei, Lactobacillus bifermentans and Enterococcus faecium predominated among the LAB in the samples of tulum cheeses; these organisms represented 30.2% of the isolates. As amino acids, tyrosine and tryptophan were determined in tulum cheeses. Tyramine and tryptamine, biogenic amines, were found at 0.00–329.00 and 0.32–40.44 mg/kg, respectively. 相似文献