A comparison of formulations and solution methods for the minimum-envy location problem

We consider a discrete facility location problem with a new form of equity criterion. The model discussed in the paper analyzes the case where demand points only have strict preference order on the sites where the plants can be located. The goal is to find the location of the facilities minimizing the total envy felt by the entire set of demand points. We define this new total envy criterion and provide several integer linear programming formulations that reflect and model this approach. The formulations are illustrated by examples. Extensive computational tests are reported, showing the potentials and limits of each formulation on several types of instances. Finally, some improvements for all the formulations previously presented are developed, obtaining in some cases much better resolution times.     

Identifying Quality-Based Requirements

This article proposes a model for identifying quality requirements based on three different views of quality. By specifying quality requirements in this manner, the framework establishes quailty requirements that can be quanitfied and measured as part of an overall quality assurance program. This results in two levels of quality: one at the system level that ensures a quality software product and another at the process level that mitigates project risk.     

Designing Quality Architecture: Incorporating ISO Standards into the Unified Process

Requirements change with the ebbs and flows of a business. Applications must be able to react to changes in the business model and, likewise, their technology platform (i.e., architecture) must be agile. Often, the operations and environment requirements of a system affect the application's ability to be modified quickly. This article presents a methodology that combines ISO standards and UML (Unified Modeling Language) standards. the ISO model is used to identify the quality characteristics for software architecture. These attributes form an evaluation framework. Each functional requirement is defined as a use case model using UML notation. This model is expanded with the specific quality properties required based on the ISO model. the resulting use cases are prioritized on the basis of their architectural impact. With these use cases, several candidate architectures can be identified. Alternatives are compared to the evaluation framework to select one architecture design. A real-time monitoring system is used as a case study to reinforce the methodology introduced in the article.     

Predicting riparian evapotranspiration from MODIS vegetation indices and meteorological data

A vegetation index (VI) model for predicting evapotranspiration (ET) from data from the Moderate Resolution Imaging Spectrometer (MODIS) on the EOS-1 Terra satellite and ground meteorological data was developed for riparian vegetation along the Middle Rio Grande River in New Mexico. Ground ET measurements obtained from eddy covariance towers at four riparian sites were correlated with MODIS VIs, MODIS land surface temperatures (LSTs), and ground micrometeorological data over four years. Sites included two saltcedar (Tamarix ramosissima) and two Rio Grande cottonwood (Populus deltoides ssp. Wislizennii) dominated stands. The Enhanced Vegetation Index (EVI) was more closely correlated (r=0.76) with ET than the Normalized Difference Vegetation Index (NDVI; r=0.68) for ET data combined over sites and species. Air temperature (T_a) measured over the canopy from towers was the meteorological variable that was most closely correlated with ET (r=0.82). MODIS LST data at 1- and 5-km resolutions were too coarse to accurately measure the radiant surface temperature within the narrow riparian corridor; hence, energy balance methods for estimating ET using MODIS LSTs were not successful. On the other hand, a multivariate regression equation for predicting ET from EVI and T_a had an r²=0.82 across sites, species, and years. The equation was similar to VI-ET models developed for crop species. The finding that ET predictions did not require species-specific equations is significant, inasmuch as these are mixed vegetation zones that cannot be easily mapped at the species level.     

Design Rules for Laser‐Treated Icephobic Metallic Surfaces for Aeronautic Applications

Ice accretion on external aircraft surfaces due to the impact of supercooled water droplets can negatively affect the aerodynamic performance and reduce the operational capability and, therefore, must be prevented. Icephobic coatings capable of reducing the adhesion strength of ice to a surface represent a promising technology to support thermal or mechanical ice protection systems. Icephobicity is similar to hydrophobicity in several aspects and superhydrophobic surfaces embody a straightforward solution to the ice adhesion problem. Short/ultrashort pulsed laser surface treatments are proposed as a viable technology to generate superhydrophobic properties on metallic surfaces. However, it has not yet been verified whether such surfaces are generally icephobic under representative icing conditions. This study investigates the ice adhesion strength on Ti6Al4V, an alloy commonly used for aerospace components, textured by means of direct laser writing, direct laser interference patterning, and laser‐induced periodic surface structures laser sources with pulse durations ranging from nano‐ to femtosecond regimes. A clear relation between the spatial period, the surface microstructure depth, and the ice adhesion strength under different icing conditions is investigated. From these observations, a set of design rules can be defined for superhydrophobic surfaces that are icephobic, too.     

Hand gesture recognition in real world scenarios using approximate string matching

New interaction paradigms combined with emerging technologies have produced the creation of diverse Natural User Interface (NUI) devices in the market. These devices enable the recognition of body gestures allowing users to interact with applications in a more direct, expressive, and intuitive way. In particular, the Leap Motion Controller (LMC) device has been receiving plenty of attention from NUI application developers because it allows them to address limitations on gestures made with hands. Although this device is able to recognize the position of several parts of the hands, developers are still left with the difficult task of recognizing gestures. For this reason, several authors approached this problem using machine learning techniques. We propose a classifier based on Approximate String Matching (ASM). In short, we encode the trajectories of the hand joints as character sequences using the K-means algorithm and then we analyze these sequences with ASM. It should be noted that, when using the K-means algorithm, we select the number of clusters for each part of the hands by considering the Silhouette Coefficient. Furthermore, we define other important factors to take into account for improving the recognition accuracy. For the experiments, we generated a balanced dataset including different types of gestures and afterwards we performed a cross-validation scheme. Experimental results showed the robustness of the approach in terms of recognizing different types of gestures, time spent, and allocated memory. Besides, our approach achieved higher performance rates than well-known algorithms proposed in the current state-of-art for gesture recognition.

     

UWB MIMO antenna implemented with orthogonal quasi‐circular slot dipole radiators

In this paper, a very low‐profile two‐port ultra‐wideband antenna for multiple input‐multiple output applications is proposed. The antenna is implemented by using two orthogonal quasi‐circular slot dipole radiators fed by coaxial lines. The antenna performs from 2 to 10 GHz, with an average peak‐gain of 4 dB, and high port isolation, with values around S₂₁ = ?20 dB and below. The radiation patterns of both antennas are opposite to each other and hence, the diversity gain reaches values around 20 dB. The low inter‐port coupling and low correlation are verified by obtaining the envelope correlation coefficient, which is lower than 0.003. These calculations were made by the S‐parameter and far‐field methods. The total active reflection coefficient shows that the antenna operative bandwidth does not change for different input signals with random phases, preserving the operation from 2 to 10 GHz. The antenna performance is compared to different state of the art slot configurations, showing advantages to previously published work.     

Grindability of lateritic nickel ores in Cuba

The purpose of this paper is to outline the findings of the evaluation of the grinding process of limonite and serpentine minerals present in oxidized Ni-Co ores, which are contained in the lateritic soils of the north-eastern region of Cuba.The grindability study supporting this paper was based on the execution of various tests aiming to determine the influence of mineral content in breakage and selection functions, and in the Bond work index. The results obtained shows that grinding behaviour of each mineral component does not depend on the mineral content in the sample.     

A methodology for territorial distribution of CO2 emission reductions in transport sector

Greenhouse gas emission reduction is the pillar of the Kyoto Protocol and one of the main goals of the European Union (UE) energy policy. National reduction targets for EU member states and an overall target for the EU‐15 (8%) were set by the Kyoto Protocol. This reduction target is based on emissions in the reference year (1990) and must be reached by 2012. EU energy policy does not set any national targets, only an overall reduction target of 20% by 2020. This paper transfers global greenhouse gas emission reduction targets in both these documents to the transport sector and specifically to CO₂ emissions. It proposes a nonlinear distribution method with objective, dynamic targets for reducing CO₂ emissions in the transport sector, according to the context and characteristics of each geographical area. First, we analyse CO₂ emissions from transport in the reference year (1990) and their evolution from 1990 to 2007. We then propose a nonlinear methodology for distributing dynamic CO₂ emission reduction targets. We have applied the proposed distribution function for 2012 and 2020 at two territorial levels (EU member states and Spanish autonomous regions). The weighted distribution is based on per capita CO₂ emissions and CO₂ emissions per gross domestic product. Finally, we show the weighted targets found for each EU member state and each Spanish autonomous region, compare them with the real achievements to date, and forecast the situation for the years the Kyoto and EU goals are to be met. The results underline the need for ‘weighted’ decentralised decisions to be made at different territorial levels with a view to achieving a common goal, so relative convergence of all the geographical areas is reached over time. Copyright © 2011 John Wiley & Sons, Ltd.