Quantitative goals for large-scale fog collection projects as a sustainable freshwater resource in northern Chile

The objective of this study was to determine the quantitative goals for a large-scale fog collection project if it were to be an economically competitive source of freshwater in northern Chile. When the initial costs are factored in, the cost of water from such a project would exceed the market price of the alternatives. However, given current costs, the project could be profitable given an average collection rate of about 10 litres per day per square metre. Investment in site selection and system improvements to reduce costs and improve collection rates are essential for making large-scale fog collection an economically competitive source of freshwater.     

Functionalization of polypropylene film by radiation grafting of acryloyl chloride and subsequent esterification with Disperse Red 1

Polypropylene (PP) films were grafted with acryloyl chloride by γ‐irradiation, and the grafted films were reacted with an azo dye, Disperse Red 1. The films were characterized by X‐ray diffraction, scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry. It was found that the grafting takes place first on the film surface, and with increase in the radiation dose the grafting penetrated inside of the film, decreasing the crystallinity of the PP film. The surface of the films was homogeneous, and a mesophase was observed for the film grafted with the dye through a polarized optical microscope. The dye underwent trans to cis photoreaction, whereby the red films became colorless by the irradiation of UV light at room temperature, although the color was recovered on standing, and more quickly when heated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 172–178, 2004     

Combining the real world with simulations for a robust testing of Ambient Intelligence services

This paper proposes a general architecture for testing, validating and verifying Ambient Intelligence (AmI) environments: AmISim. The development of AmI is a very complex task because this technology must often adapt to contextual information as well as unpredictable behaviours and environmental features. The architecture presented deals with AmI applications in order to cover the different components of these kinds of systems: environment, users, context and adaptation. This architecture is the first one that is able to cover all these features, which are needed in a full AmI system. The paper shows that AmISim is able to cover a complete AmI system and to provide a framework which can test scenarios that would be impossible to test in real environments or even with previous simulation approaches. Simulated and real elements coexist in AmISim for a robust testing, validation and verification of the AmI systems, which provide an easier and less costly deployment.     

Mixing local and global information for community detection in large networks

Clustering networks play a key role in many scientific fields, from Biology to Sociology and Computer Science. Some clustering approaches are called global because they exploit knowledge about the whole network topology. Vice versa, so-called local methods require only a partial knowledge of the network topology. Global approaches yield accurate results but do not scale well on large networks; local approaches, vice versa, are less accurate but computationally fast. We propose CONCLUDE (COmplex Network CLUster DEtection), a new clustering method that couples the accuracy of global approaches with the scalability of local methods. CONCLUDE generates random, non-backtracking walks of finite length to compute the importance of each edge in keeping the network connected, i.e., its edge centrality. Edge centralities allow for mapping vertices onto points of a Euclidean space and compute all-pairs distances between vertices; those distances are then used to partition the network into clusters.     

A unified short-cut model approach to size safe venting stacks and other blow-off devices for hazardous vapours

Starting from a general model of the atmospheric dispersion of upward-directed high velocity releases, a unified short-cut method is developed for properly designing flares, vents and other safety devices for hazardous material releases and/or to verify the adequacy of the existing ones. By comparison with the design constraints arising from the prevention and protection criteria against the risk of ignition, explosion and exposure of people to radiating heat and/or toxic compounds, the proposed procedure directly gives size, height and location of the venting system as a function of significant release characteristics. A way of economical optimisation is also considered in flare design, where raising the emission also increases the safe areas available to workers.     

First attempts at modelling earth-to-space radio propagation using SIRIO measurements in the 11 and 18 GHz bands

A bi-dimensional statistical model for earth-to-space radio links, characterized by effective rain rates and rain path lengths is proposed. These parameters refer to an equivalent homogeneous slab of rain having depth and rain rate such as to produce similar values of measured attenuations. Input data for the present study were attenuation data at 11.6 GHz (absolute and differential over a 520 MHz band) and 17 GHz, collected by the Sirio satellite: these data were found to be jointly log-normally distributed as were the effective rain rate and path length. A straightforward application of the model is the extrapolation of attenuation statistics to higher frequencies: the effectiveness of the method, when applied to 11.6 GHz data is tested against the data at 17 GHz; both the statistics and the time profiles are excellently reproduced. This suggests the use of a differential radiometer working at a relatively low frequency in order to acquire reliable higher frequency statistics and effective model parameters.     

Analysis of Virtual Irrigation Water. Application to Water Resources Management in a Mediterranean River Basin

Virtual water, understood as the volume of water needed to produce a good or service, in the context of trade among countries, allows assessing the relative dependency of different countries on imported virtual water. The assessment of virtual water flows in virtual water trade studies is generally carried out at the national level, thus concealing the spatial variability of many countries that comprise a wide range of agro-climatic areas. A finer spatial resolution is needed to apply the virtual water concept with a view to improving local water resources management at the regional or basin scale. This paper presents a more detailed analysis of blue agricultural virtual water at sub-basin scale, which is aggregated to the basin scale for the Guadalquivir River basin in southern Spain. Given that around 80% of the available blue water resources of this region are used in agriculture, improving irrigation water management is of great interest to the basin water resources management. The main objective of this paper is to estimate the virtual irrigation water balance; an important component of the agricultural water footprint that provides additional information to the basin blue water balance and contributes to achieving a more rational and efficient management of basin water resources. Management recommendations focusing on the spatial redistribution of irrigated crops according to both their water efficiency and productivity are proposed with the aim of saving blue water for other purposes such as drought mitigation or environmental flows, among others. In particular, the proposed measures affect irrigated olive trees; the most widespread irrigated crop in this basin.     

A hybrid proposal for cross-sectoral analysis of knowledge management

At present time, although many theoretical formulations have been successfully proposed, there is a lack of ICT-based tools to support practical deployment of knowledge management (KM) in real settings. To bridge this gap, a hybrid artificial intelligence system is proposed in present study, aimed at gaining deeper knowledge about KM practices in four different economic sectors. By means of soft computing, companies are diagnosed according to their status regarding KM and subsequent explanations about crucial KM practices and perspectives are generated. Interesting conclusions are then derived from these explanations, allowing KM managers to optimise their decisions and obtain better results. Experimental results of real-life data from Spanish companies associated with different economic sectors validate the proposed combination of techniques.     

Assessing the influence of stereotypes on the comprehension of UML sequence diagrams: A family of experiments

Context

The conventional wisdom states that stereotypes are used to clarify or extend the meaning of model elements and consequently should be helpful in comprehending the diagram semantics.

Objective

The main goal of this work is to present a family of experiments that we have carried out to investigate whether the use of stereotypes improves the comprehension of UML sequence diagrams.

Method

The family of experiments consists of an experiment and two replications carried out with 78, 29 and 36 undergraduate Computer Science students, respectively. The comprehension of UML sequence diagrams with and without stereotypes was analyzed from three different perspectives borrowed from the Cognitive Theory of Multimedia Learning (CTML): semantic comprehension, retention and transfer. In addition, we carried out a meta-analysis study to integrate the different data samples.

Results

The statistical analysis and meta-analysis of the data obtained from each experiment separately indicates that the use of the proposed stereotypes helps improving the comprehension of the diagrams, especially when the subjects are not familiar with the domain.

Conclusions

The set of stereotypes presented in this work seem to be helpful for a better comprehension of UML sequence diagrams, especially with not well-known domains. Although further research is necessary for strengthening these results, introducing these stereotypes both in academia and industry could be an interesting practice for checking the validity of the results.