Accurate wafer-level measurement of ESD protection device turn-onusing a modified very fast transmission-line pulse system

Quantifying the turn-on behavior of electrostatic discharge (ESD) protection devices under subnanosecond transients is critical to achieving robust protection against the Charged Device Model stress. A wafer-level very fast transmission-line pulse system (VFTLP) has been developed and is shown to successfully measure the turn-on time of a common ESD protection device. Both formal analysis and practical details regarding VFTLP system construction and operation are documented     

Short communication: Association between the accessory gene regulator (agr) group and the severity of bovine mastitis caused by Staphylococcus aureus

Staphylococcus aureus can elicit mild to more severe degrees of mastitis in cattle, depending on the response of the host's immune system and the virulence factors of the specific isolate. Several virulence factors are controlled by a global regulatory system, designated accessory gene regulator (agr). Thus, the objective was to examine associations between different capsular and agr types and the severity of bovine mastitis caused by S. aureus. All isolates were obtained from bovine subclinical (n = 50), mild clinical (n = 73), and moderate clinical mastitis cases (n = 28). Isolates containing the agrI gene and lacking the agr locus (agr^?) were more prevalent among subclinical than clinical mastitis cases, whereas isolates containing the agrII and agrIII genes were more prevalent among clinical mastitis cases. The capsular types 5 (cap5) and 8 (cap8) were found in 42 and 44%, respectively, of the isolates obtained from subclinical cases and in 38.6 and 58.4%, respectively, of those isolated from clinical mastitis cases. Capsular type was not associated with type of mastitis (subclinical, mild clinical, or moderate clinical). We found a strong association between agr type and type of mastitis, suggesting that knowledge of S. aureus genetic profiles could be an additional tool to control this disease.     

Profiling of a large-scale municipal wireless network

Pervasive connectivity is an essential underlying substrate for smart cities, leading municipalities to start programs where Wi-Fi is the fundamental building block to develop public Municipal Wireless Networks. Even though hundreds of cities around the world offer some form of Wi-Fi access, there are no widely available results regarding the network Quality of Service (QoS), user Quality of Experience (QoE), and overall utilization profile. The Municipality of São Paulo operates a free Wi-Fi Internet program in 120 public spaces called digital squares. We collected user connection data, network performance, and service availability for more than 2 years from the 120 squares and undertook experiments with video streaming in five squares. We used this unique large dataset to evaluate the impact of current admission control practices in public Wi-Fi networks on the network QoS, user QoE and service availability, also providing insights into the most common QoS/QoE issues and their causes. We also leveraged the data set to establish and verify a correlation between the number of users access in the network and specific events occurring in the area.

     

Local and global approaches for the adaptive control of a cascade of amplifiers

In this work we present and analyze three approaches for the adaptive control of the operating point of a cascade of erbium-doped fiber amplifiers (EDFAs), aimed at optical networks performance enhancement. The first approach is called Annealing Search Heuristic with Backpropagation and flexible output (AsHB flex) and uses machine learning concepts to update the amplifier gains through an iterative process. The second one (Exhaustive Method) uses an exhaustive search to evaluate all possible solutions for the problem and obtain the optimum solution. The last one (MaxGain) is a heuristic method that uses previous knowledge about the problem to obtain the solutions. The amplifier characteristics and specifications were obtained experimentally through measurements of gain, noise figure, gain ripple and power consumption on commercially available EDFAs. We performed comparisons among these approaches and others found in the literature, and the results show that the three proposals outperformed the previous ones in terms of noise figure, gain ripple and BER. For example, in a link with four amplifiers the Exhaustive Method achieved a reduction in the cascade noise figure from 10.05 to 5.18 dB, a reduction in the gain ripple from 24.08 to 18.56 dB and a reduction in the BER in almost two orders of magnitude, when compared with the traditional approach, which defines the gain to compensate the loss of the previous link. However, the computation time of Exhaustive Method becomes prohibitive as the number of amplifiers in the link increases. Both MaxGain and AsHBflex obtained similar solutions, close to the optimum operation point in a reasonable time.     

Structural topology optimization under limit analysis

Structural and Multidisciplinary Optimization - The objective of this paper is to look for structural designs arising from topological optimization procedures that aim at maximizing the loading...     

Context-Aware Routing in Delay and Disruption Tolerant Networks

In this paper, we analyze the problem of context adaptation in delay and disruption tolerant networks (DTNs). Initially, we performed experiments with well-known routing protocols to evaluate how much distinct configurations impact their performance. The results show that the performance is highly configuration dependent and improper configuration can lead to a performance up to 506.6 % worse than the best configuration tested. This motivates us to propose CARTOON (context-aware routing protocol for opportunistic networks), a novel routing protocol for DTNs based on the concept of context-adaptation. We evaluate CARTOON through simulations and the results show that our propose outperformed other well-known protocols, exhibiting results that are, on average, at 95 % of the computed optimum delivery rate.     

Modification of eucalyptus pulp fiber using silane coupling agents with aliphatic side chains of different length

The objective of this work was to evaluate the effect of three silane coupling agents with different aliphatic chain lengths on the hydrophobicity of eucalyptus pulp fiber. The three silanes coupling agents used (isobutyltrimethoxysilane, methyltrimethoxysilane, and n‐octyltriethoxysilane [OTES]) were each tested at three concentrations. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed that the silane coupling agents markedly increased the Si content of the treated fibers. The Si distribution was not completely homogenous but was abundant in the treated samples. The treated fibers had higher contact angles for water and lower moisture adsorption than the control. Of the coupling agents tested, OTES treated fibers had the highest moisture resistance. This was likely due to the greater chain length of the aliphatic side group coupled to OTES. The use of silane coupling agents with alkyl side chains could improve the functional properties of pulp fiber and increase its compatibility with hydrophobic polymers. POLYM. ENG. SCI., 55:1273?1280, 2015. © 2015 Society of Plastics Engineers