Advanced processing techniques of high-voltage impulse test signals

Automated analysis and processing of the digital records obtained in high-voltage (HV) impulse tests requires special techniques that are able to detect and characterize all sorts of disturbances (of short and long duration) in all waveform types (full, chopped, and sliced). Especially for the cases where a short-duration disturbance has to be removed before the evaluation of the impulse parameters, it is important to characterize the disturbance both in time and frequency. This paper describes a new technique based on the wavelet transform used for this purpose. Experimental results show the technique's reliability when applied to actual HV impulses     

Indexing valid time databases via B+-trees

We present an approach, named MAP21, which uses standard B⁺ -trees to provide efficient indexing of valid time ranges. The MAP21 approach is based on mapping one dimensional ranges to one dimensional points where the lexicographical order among the ranges is preserved. The proposed approach may employ more than one tree, each indexing a disjoint subset of the indexed data. When compared to the Time Index and the B⁺-tree we show that MAP21's performance is comparable to or better than those, depending on the type of query. In terms of storage, MAP21's structure was less than 10 percent larger than the B⁺-tree's and much smaller than the Time Index's. The main contribution of this paper though, is to show that standard B ⁺-trees, available in virtually any DBMS, can be used to provide an efficient temporal index     

Health promotion and education: a diagnosis of sanitation conditions using participatory research and community education (S?o Jo?o dos Queiróz - Quixadá/Ceará, Brazil)

This study was conducted in a rural community, S?o Jo?o dos Queiróz, a township in the county of Quixadá, Ceará, Brazil, using a combination of participatory research and community education in compliance with the health promotion reference and principles of the 1986 Ottawa Charter. The project was joined by representatives of several local government institutions and organizations from the grassroots community movement. The theme generating the research, as defined by an assembly meeting of the community association, was a diagnosis of sanitation conditions in the community. The starting point was the assessment of local conditions. Results showed adverse local conditions in sanitation, literacy, income, and employment. Suggestions for solving the problems were organized so as to be included in the planning agenda for local health policies. Evaluation was procedural and enriched with daily research activities. The problem-solving pedagogical approach developed during the educational process contributed to a critical reconstruction, appropriation, and sharing of the resulting knowledge.     

MoCA: A Middleware for Developing Collaborative Applications for Mobile Users

The Mobile Collaboration Architecture is a middleware architecture for developing and deploying context-aware collaborative applications for mobile users. MoCA comprises client and server APIs, a set of core services for registering applications, the ability to monitor and infer the execution context of mobile devices, and an object-oriented framework for instantiating and customizing server proxies according to applications’ specific adaptation and context-processing requirements. MoCA facilitates the development of distributed programs that require access to individual and group context to define application-specific and dynamic adaptations. MoCA’s design focuses on simplicity, extensibility, scalability, protocol heterogeneity, and application customization.     

Human Head Size and SAR Characteristics for Handset Exposure

Using scaled models for an anatomical head model and a simple head model, we investigated the effects of head size on specific absorption rate characteristics for two mobile phones operating at 835 MHz and 1765 MHz. Our results showed that a larger head produced a higher localized SAR at 835 MHz. However, at 1765 MHz, the differences among the head models were insignificant since the superficial absorption was dominant over the effects of head shape and size. A larger head produced a lower whole‐head averaged SAR at both frequencies.     

Guest Editorial: Best Papers of the ACM Multimedia 2001 Workshop on Multimedia Information Retrieval

Multimedia Tools and Applications -     

Assessment of glass-forming ability and the effect of La2O3 on crystallization mechanism of barium-lead-zinc phosphate glasses

Differential scanning calorimetry (DSC) was used in this work to study the effect of La₂O₃ addition on crystallization mechanism of barium-lead-zinc phosphate glasses. Bulk glasses from two different routes (using P₂O₅ and H₃PO₄ as starting materials) presented only one crystallization peak. An assessment of glass-forming ability (GFA) was performed from recent theory that is connected to glass stability (GS), and is also correlated to critical cooling rate, q_cr. Systems with high La₂O₃ content presented some of the highest GS values and estimated critical cooling rates (q_cr) lower than 0.079 K/s. For both routes were determined the activation enthalpies for crystallization, that were 126 ± 12 kJ/mol (for P₂O₅) and 110 ± 32 kJ/mol (for H₃PO₄). The calculated Avrami n parameters, based on exothermic crystallization peaks, were 3.50 ± 0.33 (for P₂O₅) and 3.09 ± 0.91 (for H₃PO₄), considering data from the lowest heating rate (5 K/min). These values suggest that the DSC peaks should be associated to volume crystallization, due to La₂O₃ influence, and crystallization did not change significantly using different routes.     

Deformable strut and tie model for the calculation of the plastic rotation capacity

When a plastic analysis, a non-linear analysis or a linear analysis followed by redistribution of bending moments is used to predict the structural behaviour of beams, the critical sections should have the necessary plastic rotation capacity to allow the predicted behaviour at failure. When some doubts may arise, then an explicit calculation of this capacity must be carried out. This paper presents a theoretical model for the calculation of plastic rotation, considering the influence of the main factors. Some results are presented on the basis of the model, and conclusions are drawn.     

Prediction-based energy map for wireless sensor networks

A fundamental issue in the design of a wireless sensor network is to devise mechanisms to make efficient use of its energy, and thus, extend its lifetime. The information about the amount of available energy in each part of the network is called the energy map and can be useful to increase the lifetime of the network. In this paper, we address the problem of constructing the energy map of a wireless sensor network using prediction-based approach. Simulation results compare the performance of a prediction-based approach with a naive one in which no prediction is used. Results show that the prediction-based approach outperforms the naive in a variety of parameters. We also investigate the possibility of sampling the energy information in some nodes in the network in order to diminish the number of energy information packets. Results show that the use of sampling techniques produce more constant error curves.     

Reduction of crotoxin-induced neuromuscular blockade by gamma radiation

OBJECTIVES: This study evaluated the application of ultrasound (US) guidance in the percutaneous placement of gastric feeding tubes in patients in whom endoscopic placement of a nutrition tube is not possible. METHODS: Thirty-eight patients with upper gastrointestinal obstruction were entered in a prospective study with US-guided nutrition tube application. Feasibility of placement, side effects, and nutritional states were monitored for a mean follow-up of 4 months. RESULTS: Ultrasound allowed rapid puncture after filling of the stomach with water through a nasal tube in 34/38 cases. In four cases a total upper gastrointestinal obstruction required an initial stomach insufflation through a direct puncture. Puncture-related major complications were not observed. Minor complications during the observation time were one late dislocation, five cases with broken material after about 6 months (four could be changed by using the Seldinger technique), and two minor local infections. The nutrition through feeding tubes stabilized body weight and body composition parameters. CONCLUSION: The percutaneous sonographic gastrostomy (PSG) is a safe and minimally invasive procedure for enteral nutrition in all cases with upper gastrointestinal obstruction when endoscopic placement of a feeding tube is not possible. Percutaneous sonographic gastrostomy may help to stabilize the nutritional parameters and general condition in patients with malignant diseases.