Understanding the differences between how novice and experienced designers approach design tasks

Research was undertaken to understand how to provide the most appropriate support for novice designers in engineering design. However, how designers apply their experience and knowledge is not understood and further research in this area is required. This paper describes an observational study to understand how novice and experienced designers approach design tasks. Electronic Publication     

SUTIL – Network selection based on utility function and integer linear programming

This work presents SUTIL, a mechanism for network selection in the context of next generation networks (NGN). SUTIL selection mechanism prioritizes networks with higher relevance to the application and lower energy consumption and it enables full and seamless connectivity to mobile user devices and applications. Consequently, SUTIL contributes to realize the vision of ubiquitous computing, in which services, devices, and sensor-enriched environments interact anytime, anywhere to accomplish human designed tasks. The provided solution is based on utility function and integer linear programming and it aims at: (i) maximizing the user satisfaction while meeting application QoS and (ii) minimizing the energy consumption of devices when connecting to a target network. The solution is global since it considers for a given base station all devices that are simultaneously candidate for handoff. Simulation results showed the benefits of SUTIL usage in NGN environments.     

An efficient heuristic for selecting active nodes in wireless sensor networks

Energy saving is a paramount concern in wireless sensor networks (WSNs). A strategy for energy saving is to cleverly manage the duty cycle of sensors, by dynamically activating different sets of sensors while non-active nodes are kept in a power save mode. We propose a simple and efficient approach for selecting active nodes in WSNs. Our primary goal is to maximize residual energy and application relevance of selected nodes to extend the network lifetime while meeting application-specific QoS requirements. We formalize the problem of node selection as a knapsack problem and adopt a greedy heuristic for solving it. An environmental monitoring application is chosen to derive some specific requirements. Analyses and simulations were performed and the impact of various parameters on the process of node selection was investigated. Results show that our approach outperforms a naı¨ve scheme for node selection, achieving large energy savings while preserving QoS requirements.     

Electron beam irradiation effects on the mechanical, thermal and surface properties of a fluoroelastomer

Fluoroelastomer can be used as a sealing material for different purposes. The aim of this work is the evaluation of the effects of the ionizing radiation of an electron beam (EB) on the mechanical, thermal and surface properties of a commercial fluoroelastomer containing carbon black and inorganic fillers. The material was irradiated with overall doses between 10 and 250 kGy. Tensile strength (stress and strain at break), hardness (Shore A) and compression set were evaluated. Thermal behavior was evaluated by thermogravimetric analysis and differential scanning calorimetry. Surface modifications were inspected using scanning electron microscopy (SEM) and optical microscopy. The experiments have shown that EB irradiation promotes beneficial changes in the fluoroelastomer tensile strength behavior while compression set remain constant and the glass transition temperature increases. The SEM micrographs have shown compactness in the irradiated samples, although optical observations showed no surface morphology changes.     

Intrusion Detection System for Wireless Sensor Networks Using Danger Theory Immune-Inspired Techniques

An IDS framework inspired in the Human Immune System to be applied in the wireless sensor network context is proposed. It uses an improved decentralized and customized version of the Dendritic Cell Algorithm, which allows nodes to monitor their neighborhood and collaborate to identify an intruder. The work was implemented and tested both in simulation and in real sensor platform scenarios, comparing them to each other and was also compared to a Negative Selection Theory implementation in order to demonstrate its efficiency in detecting a denial-of-sleep attack and in energy consumption. Results demonstrated the success of the proposal.     

Laryngeal sarcomatoid carcinoma: clinical, histological and immunohistochemical study of four cases

A 1488-bp fragment of bovine retina guanylate cyclase B gene encoding the catalytic and dimerizing domains as well as part of the protein kinase domain was expressed in Escherichia coli cells. The expression product was obtained as inclusion bodies and solubilized in 6 M guanidine hydrochloride. The fragment of guanylate cyclase B is a dimer close in catalytic activity to the native enzyme.     

Role of prior prey-eating experiences in the initiation of predation by rats.

Studied mouse killing by more than 400 male and female Sprague-Dawley rats in 6 experiments after Ss had been maintained on various flesh diets. Ss maintained on dead mice killed live mice more often than did Ss on Purina Chow, under both ad-lib feeding and food deprivation conditions. The effect was not dependent on these eating experiences taking place early in life, but there was suggestive evidence that the more there were of such feedings, the higher were the probabilities of subsequent killing. Ss maintained on flesh diets other than dead mice did not kill more than did Purina-maintained controls. Consequently, neither a chemical mechanism that would prime brain centers for predatory attack nor response-learning (e.g., biting hard) processes easily account for the phenomenon. Rather, stimulus generalization, the transfer of biting a dead mouse to biting a live mouse, is the simplest explanation. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social facilitation and inhibition to hunger-induced killing by rats.

Gave 162 male Long-Evans rats different types of experiences to alter their mouse- and rat-pup-killing behavior. First, hungry Ss given considerable experience in mouse killing did kill rat pups, whereas inexperienced Ss were unlikely to kill pups. Second, nonkilling experiences subsequently inhibited hunger-induced mouse killing. Nonkilling experience was given by presenting rat pups and mice to food-satiated Ss and by presenting rat pups to hungry Ss. Inhibition was greater when pups were presented to satiated Ss rather than to hungry, and when pups, rather than mice, were used as inhibitory stimuli. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predation and feeding: Comparisons of feeding behavior of killer and nonkiller rats.

Studied feeding behavior of 34 killer and 34 nonkiller male Long-Evans rats when (a) hungry, (b) with food available, and (c) with prey and other food of high and low palatability. 3 experiments showed that the act of killing did not potentiate feeding but killers were more responsive to dead prey as food than were nonkillers. Results of this and previous studies suggest that the relationship between attack and feeding is not important to the maintenance of killing. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)