Quality of service for voice over IP in networks with congestion avoidance

This paper assesses the impact of active queue management schemes on the quality of service of voice over Internet protocol applications. A new analytical method based on a fixed point approach to estimate the end-user satisfaction is proposed. The results obtained were validated using discrete event simulation techniques. In all the studied cases, it was observed a great deal of agreement between the analytical results and the results obtained through simulation. The theoretical predictions, as well as the presented empirical evidences confirm, as demonstrated in previous works, that the use of active queue management offers better quality of service than the traditional queue control mechanisms used in Internet. From these results, we may reasonably conclude that the presented method can be used for network design in the presence of voice traffic.     

Hydraulic/partitioning tracer tomography for DNAPL source zone characterization: small-scale sandbox experiments

Dense nonaqueous phase liquids (DNAPL) are prevalent at a large number of sites throughout the world. The variable release history, unstable flow, and geologic heterogeneity make the spatial distribution of DNAPLs complex. This causes difficulties in site remediation contributing to long-term groundwater contamination for decades to centuries. We present laboratory experiments to demonstrate the efficacy of Sequential Successive Linear Estimator (SSLE) algorithm that images DNAPL source zones. The algorithm relies on the fusion of hydraulic and partitioning tracer tomography (HPTT) to derive the best estimate of the K heterogeneity, DNAPL saturation (S(N)) distribution, and their uncertainty. The approach is nondestructive and can be applied repeatedly. Results from our laboratory experiments show that S(N) distributions compare favorably with DNAPL distributions observed in the sandbox but not so with local saturation estimates from core samples. We also found that the delineation of K heterogeneity can have a large impact on computed S(N) distributions emphasizing the importance of accurate delineation of hydraulic heterogeneity.     

Verbundlose interne Vorspannung von weitgespannten Plattentragwerken im Hochbau

Internal unbounded Posttensioning in Wide Span Slabs for Building Constructions In order to comply with the needs of robustness and economy to be considered in design and construction, the internal, unbounded posttensioning has been optimized, in a way to install the cables with the minimum necessary amount of work. For this purpose a free system of posttensioning cables has been adopted, in which border uplift forces (in correspondence of the supports) and single or multiple midspan uplift forces are necessary. The deviation forces helps to limit the deflections and cracks. In this paper after some theoretical reflections two innovative practical applications are presented. On the basis of the mechanics of the load bearing behaviour and with three dimensional finite element calculations also the soil‐structure interaction have been taken into account.     

One-Step Reverse Osmosis Based on Riverbank Filtration for Future Drinking Water Purification

The presence of newly emerging pollutants in the aquatic environment poses great challenges for drink-ing water treatment plants.Due to their low concentrations...     

适用于传感器接口的可编础大器

现今大多数的电子仪器均属于嵌入式系统,内含传感器、缓冲和放大信号的放大器、模拟／数字转换器和一个数据处理和使用者接口的微控制器,像是数据撷取系统和数据记录器等。图1表示一个典型设有USB接口的数据撷取系统的区块图。     

A Test Generation Methodology for Interconnection Opens Considering Signals at the Coupled Lines

Interconnection opens have become important defects in nanometer technologies. The behavior of these defects depends on the structure of the affected devices, the trapped gate charge and the surrounding circuitry. This work proposes an enhanced test generation methodology to improve the detectability of interconnection opens. This test methodology is called OPVEG. OPVEG uses layout information and a commercial stuck-at ATPG. Those signal values at the coupled lines which favor the detection of the opens, under a boolean based test, are attempted to be generated. The methodology is applied to four ISCAS85 benchmark circuits. The results show that a significant number of considered coupled signals are set to proper logic values. Hence, the likelihood of detection of interconnection opens is increased. The results are also given in terms of the amount of coupling capacitance having logic conditions favoring the defect detection. This shows the OPVEG benefits. Furthermore, those lines difficult to test can be identified. This information can be used by the designer to take design for test measures.

A Management Framework for Ambient Systems Operating in Wireless B3G Environments

As the wireless world is rapidly evolving towards the “Beyond the 3rd Generation” (B3G) era, communication infrastructures need to tackle external conditions that are continuously changing, and thus become less predictable in terms of quality of service (QoS) provision. On the contrary, the B3G era, through the coexistence and complementary use of a multitude of Radio Access Technologies (RATs), offers additional capabilities for providing users with advanced levels of convenience and flexibility for living and working. Those advances in communications and networking technology are making it possible to devise ‘ambient’ systems, i.e. systems that realize the vision of an all-encompassing multimedia networking environment, which is aware of the users’ presence and context, and is sensitive, adaptive, and responsive to their needs, habits, gestures and emotions. All above pose significant challenges regarding the intelligent management of heterogeneous wireless infrastructures. In the light of the above, this paper presents such an advanced management framework, as an enabling technology for designing and developing ambient, wireless systems in B3G environments. The paper focuses on the main components of the proposed framework, as well as on their functionality and interactions. Additionally, indicative simulation results showcase the efficiency of the proposed framework.     

Comparison of the compositional, microbiological, biochemical and volatile profile characteristics of three Italian PDO fermented sausages

Three Italian PDO fermented sausages, Varzi, Brianza and Piacentino, were compared for compositional, microbiological, biochemical and volatile profile characteristics. Mean values for the gross composition varied especially due to moisture, fat, total protein and nitrate concentration which reflected differences in the ingredients and some technological parameters. Cell numbers of the major microbial groups were almost similar among sausages. The major differences were found for Brochothrix thermosphacta, enterococci and moulds. Apart from their use as starters, Lactobacillus sakei and Lactobacillus curvatus were the dominant lactic acid bacteria and, as well as Staphylococcus xylosus, dominated the population of coagulase-negative staphylococci. Sausages differed for the hydrolysis of myofibrillar proteins and secondary proteolysis. Varzi, the sausage subjected to prolonged fermentation at 23–25 °C for 10 days before ripening, showed the highest degree of secondary proteolysis. Varzi and Brianza, the two fermented sausages manufactured by using microbial starters, showed the highest concentration and similar profiles of free amino acids. The peptidase activities contained in the aqueous extracts agreed with the above findings. A total of 52 volatile components, mainly alcohols, aldehydes and terpenes, were identified by solid-phase micro-extraction coupled with gas chromatography–mass spectrometry analysis. The volatile profiles of the three Italian PDO fermented sausages differed in part and, except for terpenes, the highest levels of the other chemical classes were found in Varzi and Brianza sausages. The composition of free fatty acids of the three Italian PDO sausages was rather similar. Monounsaturated fatty acids (MUFA) were found at the highest relative percentage followed by saturated (SFA) and polyunsaturated (PUFA) fatty acids. Oleic, palmitic, linoleic and stearic were the main free fatty acids found in all fermented sausages.     

Antimicrobial activity of sub- and supercritical CO2 extracts of the green alga Dunaliella salina

The objective of this research was to evaluate the antimicrobial activity of carbon dioxide extracts of the unicellular biflagellated green alga Dunaliella salina against Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger. The effects of different extraction pressures ranging from 185 to 442 bar and extraction temperatures ranging from 9.8 to 45.2 degrees C on the extracts' composition and consequently on their antimicrobial activities were investigated. The extracts were analyzed by gas chromatography-mass spectrometry in order to identify the compounds responsible for the antimicrobial activity detected. Fourteen different volatile compounds and several fatty acids were identified. The highest antimicrobial activity was obtained using 314 bar and 9.8 degrees C. Under these conditions, the presence of an indolic derivative that had never been reported in D. salina was detected in the extract, together with polyunsaturated fatty acids and compounds related to carotene metabolism, such as beta-ionone and neophytadiene, with known antimicrobial activity.