Josep Maria Mateo-Sanz

Universitat Rovira i Virgili, Tarraco, Catalonia, Spain

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Publications (50)66.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A wide range of impact assessment methodologies are available for quantifying the life cycle environmental impact of anthropogenic activities. The calculation of these metrics requires typically large amounts of data that are hard to collect in practice. To shed light on the extent to which these input data can be reduced (while yet obtaining accurate impact assessment values), this work applies a multivariate statistical analysis to the ecoinvent database. Numerical results show that many life cycle impact assessment (LCIA) metrics are highly correlated, but despite this high level of correlation no single indicator is capable of predicting the others with accuracy via univariate linear regression. Our findings open new avenues for the development of advanced streamlined LCIA methods based on multiple data regression that could exploit this high level of correlation and potentially lead to significant savings in time and resources associated with LCA studies.
    No preview · Article · Jun 2015 · Journal of Cleaner Production
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    ABSTRACT: Understanding how anthropogenic impacts are generated at a global scale is a major challenge to face. This work studies the environmental impact patterns of the wealthiest nations using environmentally extended multi-regional input–output tables. A multivariate statistical analysis is performed on data covering 69 environmental indicators (classified into 5 main categories: energy, emissions, material, water and land) and 41 countries. This analysis shows that damages in different categories (and also within the same one) are highly correlated and that the wealthiest countries display very similar environmental impact patterns. These findings might help to develop more effective environmental regulations that will focus on controlling a reduced number of key indicators. In addition, the analysis of pollution patterns at a global scale will help to establish unified environmental regulations in countries with similar patterns.
    Full-text · Article · Mar 2015 · Journal of Cleaner Production
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    ABSTRACT: In the recent past, the study of the international channels through which impacts are traded at a global scale has gained wider interest. In this context, environmentally extended multi-regional input-output tables (EEMRIO) are widely used to assess the impact of economic activities on the environment.These models are a valuable tool to attribute pollution or resources depletion to the final demand of a product or service following a consistent approach, which makes them very useful in the development of environmental policies. A key point in their use and, more generally, in the area of environmental engineering, concerns how the environmental performance is assessed. A plethora of environmental indicators are available for quantifying the anthropogenic damage in different categories. Among them, those based on Life Cycle Assessment (LCA) principles have recently become the prevalent approach. Many methods for impact assessment have been presented so far (in general), and some of them have been incorporated into IO models (in a more specific field). In contrast, the relationships between impacts in different damage categories are poorly understood at both, the local and global scales. Particularly, at a global scale, little effort has been devoted to the study of the environmental impact patterns of nations. The analysis of these global impact fingerprints, however, could assist in the development of more effective environmental policies in several ways. In this work, we apply a multivariate statistical analysis to data retrieved from a multi-regional input-output (IO) table covering 69 environmental indicators classified into 5 main categories: energy, emissions, material, water and land; and 41 countries. We find that damages in different categories and also within the same one are highly correlated. In addition, our statistical analysis reveals that countries show a very similar environmental impact pattern. While the environmental fingerprint of nations is similar, the intensity is different depending on the level of development. Our findings might help to develop more effective environmental regulations.
    No preview · Conference Paper · Nov 2014
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    ABSTRACT: Web Search Engines store and analyse queries made by their users in order to build their profiles and offer them personalized search results (i.e., results are ranked according to each user’s preferences). Even though this service is positive for the users, their profiles may contain sensitive information that can threaten their privacy. Literature in this field stresses the existence of a trade-off between the level of privacy achieved and the quality of service received. Current proposals try to maximize this trade-off, yet we argue that there is still room for improvement. In this paper, we present a new approach which improves the trade-off by grouping users who share similar profiles. Moreover, our new proposal is based on a hybrid P2P architecture that outperforms current schemes in terms of scalability. The proposed system has been tested in terms of performance and privacy achieved, using real data from the AOL dataset. Simulation results show that: (i) the system protects users’ privacy when they behave honestly, and penalizes selfish users; (ii) it supports a large number of users; (iii) the runtime required to group users is affordable; and (iv) groups are dynamic and their topology is unpredictable, which we argue that is positive from the privacy point of view.
    No preview · Article · Sep 2014 · Computer Communications
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    ABSTRACT: Multi-objective optimization (MOO) has recently emerged as a useful technique in environmental engineering. One major limitation of this approach is that its computational burden grows rapidly with the number of environmental objectives, which causes difficulties regarding the computation and visualization of the Pareto solutions. In this work we present several theoretical and algorithmic developments for grouping environmental objectives into clusters on the basis of which the multi-objective optimization can be performed, thereby facilitating the computation and analysis of the Pareto solutions. Our method is based on a novel mixed-integer linear program (MILP) that identifies in a systematic manner groups of objectives that behave similarly. We test the capabilities of our approach using several examples, in which we compare it against other well-known clustering methods.
    Full-text · Article · Sep 2013 · Computers & Chemical Engineering
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    ABSTRACT: The presented work analyses the feasibility of biodiesel production by transesterification of vegetable oil extracted from Cynara Cardunculus. The performance assessment of a plant with a capacity of 5000 t/year biodiesel production is carried out based on its rigorous simulation in AspenHysys®. A modular automated evaluation tool programmed in Matlab® retrieves the inventory of the energy and material inputs/outputs, and the environmental releases from the simulation results. The simulation performs a combined acid-catalyzed pretreatment and alkali-catalyzed transesterification based on the cardoon oil characterization and the kinetic data extracted from published experimental studies. The performance of the plant is optimized considering four potential alternatives. The Eco-indicator 99 methodology is used for the impact assessment, achieving similar results to other vegetable sources of biodiesel. With respect to the economic study, a profitability analysis yields better results than the reported in previous works for oils of other agricultural crops, identifying two critical factors: the biodiesel sale price and the plant capacity.
    Full-text · Article · Sep 2013 · Fuel
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    ABSTRACT: Microalgae-based biodiesel has several benefits over other resources such as less land use, potential cultivation in non-fertile locations, faster growth and especially a high lipid-to-biodiesel yield. Nevertheless, the environmental and economic behavior for high scale production depends on several variables that must be addressed in the scale-up procedure. In this sense, rigorous modeling and multicriteria evaluation are performed in order to achieve optimal topology for third generation biodiesel production. Different scenarios and the most promising technologies tested at pilot scale are assessed. Besides, the sensitivity analysis allows the detection of key operating variables and assumptions that have a direct effect on the lipid content. The deviation of these variables may lead to an erroneous estimation of the scale-up performance of the technology reviewed in the microalgae-based biodiesel process. The modeling and evaluation of different scenarios of the harvesting, oil extraction and transesterification help to identify greener and cheaper alternatives.
    Full-text · Article · Aug 2013 · Bioresource Technology
  • Josep M. Mateo-Sanz · Dolors Puigjaner · Carme Olivé
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    ABSTRACT: This paper describes two new Moodle modules that were developed to enhance a problem-based learning approach. One of the modules offers the possibility to easily customize student assessment. In particular, it enables the creation of questions containing random numeric variables, either scalar or vectorial, and whose answers are automatically computed regardless of the complex combination of numerical and logical operations involved in their calculation. The other module facilitates the subdivision of a problem into a common statement and a set of questions which are successively displayed in the browser. By combining these two modules, instructors can easily offer their students the opportunity to practice answering individualized quizzes anywhere and anytime. The analysis of the effect of the use of these two modules on students’ performance revealed the existence of a strong link between the amount of online problems answered by students and their final grades. Typically, higher final grades were associated to higher regularity in answering individualized online problems. Moreover, it was shown that the use of individualized assessment quizzes tends to reduce academic dishonesty.
    No preview · Article · Aug 2013 · International Journal of Engineering Education
  • Agusti Solanas · Antoni Martínez-Ballesté · Josep Maria Mateo-Sanz
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    ABSTRACT: In this paper, we present the concept of double-phase microaggregation as an improvement of classical microaggregation for the protection of privacy in distributed scenarios without fully trusted parties. We apply this new concept in the context of mobile health and we show that a distributed architecture consisting of patients and several intermediate entities can apply it to protect the privacy of patients, whose data are released to third parties for secondary use. After recalling some fundamental concepts of statistical disclosure control and microaggregation, we detail the distributed architecture that allows the private gathering, storage, and sharing of biomedical data. We show that double-phase multivariate microaggregation properly fits the needs for privacy preservation of biomedical data in the distributed context of mobile health. Moreover, we show that double-phase microaggregation performs similarly to classical microaggregation in terms of information loss, disclosure risk, and correlation preservation, while avoiding the limitations of a centralized approach.
    No preview · Article · Jun 2013 · IEEE Transactions on Information Forensics and Security
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    Carmen M. Torres · Mamdouh Gadalla · Josep M. Mateo-Sanz · Laureano Jiménez
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    ABSTRACT: In this work a real sour stripping plant of a petrochemical complex simulated in AspenHysys (R) is improved using an automated tool programmed in Matlab (R). The new developed procedure provides the performance evaluation and the comparison between different alternatives of the plant through the calculation and aggregation of environmental and economic indicators. The results obtained give insights into the plant environmental behavior, being very useful to find the suitable modifications in operation and topology of the plant. Moreover, the use of this tool allows the implementation of optimization algorithms and heat integration strategies, with the aim of minimizing resources consumption, pollutants releases, energy requirements and total costs. Specifically, the procedure helps to significantly improve the performance of the studied process: the operating costs are reduced near 8%, while the amount of released CO2-eq is 7% lower, and the process consumes 66% less water.
    Full-text · Article · Apr 2013 · Journal of Cleaner Production
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    ABSTRACT: Microalgae oil has been identified as a reliable resource for biodiesel production due to its high lipid productivity and potential cultivation in non-fertile locations. However, high scale production of microalgae based biodiesel depends on the optimization of the entire process to be economically feasible. The selected strain, medium, harvesting methods, etc., sorely affects the ash content in the dry biomass which have a direct effect in the lipid content. Moreover, the suitable lipids for biodiesel production, some of the neutral/saponifiable, are only a fraction of the total ones (around 30% dry base biomass in the best case). The present work uses computational tools for the modeling of different scenarios of the harvesting, oil extraction and transesterification. This rigorous modeling approach detects process bottlenecks that could have led to an overestimation of the potentiality of the microalgae lipids as a resource for the biodiesel production.
    Full-text · Article · Mar 2013 · Bioresource Technology
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    Alexandre Viejo · Jordi Castellà-Roca · Oriol Bernado · Josep Maria Mateo-Sanz
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    ABSTRACT: Web search engines profile their users by storing and analyzing their past searches. Profiles reflect the interests of the users and enable web search engines to offer a better service. In this way, search results are personalized to fulfill the expectations of each individual user. Nevertheless, this service is not provided without cost. User profiles contain information that can be considered private and personal. This represents a serious privacy threat which must be addressed. Several privacy-preserving techniques which try to prevent this situation can be found in the literature. In this paper, we focus on those that work directly in the computer of the users without requiring any external entity. More specifically, we propose a new single-party scheme that addresses the trade-off between privacy and quality of service but it does not require any change at the server side. The performance of this new method has been evaluated using real search queries extracted from the AOL's files. The results achieved show that our proposal works as expected and it can be considered a proper option for those users who are concerned about their privacy.
    Full-text · Conference Paper · Jul 2012
  • Carmen M. Torres · Mamdouh Gadalla · Josep M. Mateo-Sanz · Laureano Jiménez
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    ABSTRACT: The aim of this work is to show the improvements achieved in terms of sustainability, environment and economic profit in a specific process design problem. The procedure combines rigorous simulation in Hysys® with an environmental evaluation tool programmed in Matlab®. This tool determines categorized impacts using the simulation results and a final global index through an aggregation method based on the geometric mean of the ratios of impacts with respect to the base case. This Hysys®-Matlab® connection allows us the automation in the modification of simulation variables, in the calculation of the environmental impacts, and in the implementation of optimization tools. The procedure is tested using a case study (styrene production), where data obtained from rigorous simulation validated with industrial data.
    No preview · Article · Jan 2012 · Computer Aided Chemical Engineering
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    ABSTRACT: Since the environmental awareness increases and regulations become more restrictive, chemical industries are forced to adopt measures for minimizing the environmental impact and to include these techniques in the process design. This work proposes a methodology where environment and human health considerations are coupled with the process design of new and existing plants. With this aim, a new assessment tool for the environmental evaluation of chemical processes is presented. It includes the development of a new environmental indicator (Material Balance Environmental Index, MBEI) based on the toxicities of the chemicals involved and the materials flows between the process and environment. Moreover, a total index is computed following three levels of aggregation using the geometric mean of the ratios of several environmental impact categories. The environmental evaluation tool is tested using two case studies (formaldehyde and styrene production), where data are obtained from rigorous process simulation validated with industrial data.
    Full-text · Article · Oct 2011 · Industrial & Engineering Chemistry Research
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    Arnau Erola · Jordi Castellà-Roca · Alexandre Viejo · Josep Maria Mateo-Sanz
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    ABSTRACT: Web search engines (WSE) have become an essential tool for searching information on the Internet. In order to provide personalized search results for the users, WSEs store all the queries which have been submitted by the users and the search results which they have selected. The AOL scandal in 2006 proved that this information contains personally identifiable information which represents a privacy threat for the users who have generated it. In this way, AOL released a file containing twenty million queries made by 658,000 persons and several of those users were successfully tracked. In this paper, we propose a P2P protocol that exploits social networks in order to protect the privacy of the users from the profiling mechanisms of the WSEs. The proposed scheme has been designed considering the presence of users who do not follow the protocol (i.e., adversaries). In order to evaluate the privacy of the users, we have designed a new measure (the profile exposure level (PEL)). Finally, we have used the AOL's file in order to simulate the behavior of our scheme with real queries which have been generated by real users. Our tests show that our scheme is usable in practice and that it preserves the privacy of the users even in the presence of adversaries.
    Preview · Article · Oct 2011 · Journal of Systems and Software
  • Josep M. Mateo-Sanz · Agusti Solanas · Dolors Puigjaner · Carme Olive
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    ABSTRACT: Statistics is fundamental to many disciplines and plays a central role in Engineering and Sciences. To understand and apply statistics requires students to be highly motivated. Therefore, fostering students' learning and reducing dropout rates implies increasing students' motivation. We present a guided problem-based learning approach to teaching statistics in hybrid learning environments and we analyse its impact on students' motivation. We pay special attention at subdividing problems into small sections to obtain detailed sets of questions associated with specific concepts or procedures. This degree of detail guarantees that students can easily tackle these problems in virtual learning environments. In addition, thanks to the use of automatically generated log files, our proposal allows teachers to finely analyse the steps in which students have difficulties. We assess our proposal in terms of student satisfaction and motivation. The results show that although success rates are not improved, students' motivation for the subject increases. Consequently, our approach is a good choice to improve motivation and reduce the dropout rate in difficult subjects such as Statistics.
    No preview · Article · Jan 2010 · International Journal of Engineering Education
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    ABSTRACT: Highly microporous carbon materials with high apparent surface areas (up to 2400 m2·g−1) were obtained by heat treatment of mixtures of demineralized Kraft lignin and sodium hydroxide. The application of a statistical tool, the response surface methodology, was used to determine the optimum operation conditions for preparing activated carbon able to adsorb large quantities of organic compounds. For that purpose, three parameters were varied: temperature of activation, sodium hydroxide and demineralized Kraft lignin percent mass ratio, and nitrogen flow rate. This carbon was tested for the adsorption of methylene blue that is a model compound for the most usual organic pollutant behavior, such as dyes. The adsorption of methylene blue was 93.2 g/100 g activated carbon, and this has a high microporosity and a specific surface area of 2610 m2·g−1. The optimum preparation conditions of this best activated carbon were determined at 755 °C, 22.4 % Kraft lignin, and 200 cm3 N2·min−1.
    Full-text · Article · Aug 2009 · Journal of Chemical & Engineering Data
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    ABSTRACT: Flavonoids are functional constituents of many fruits and vegetables. Procyanidins are flavonoids with an oligomeric structure, and it has been shown that they can improve the pathological oxidative state of a diabetic situation. To evaluate whether procyanidins can modulate inflammation, an event strongly associated with obesity, diabetes and insulin resistance states, we used human adipocytes (SGBS) and macrophage-like (THP-1) cell lines and administered an extract of grape-seed procyanidins (GSPE). THP-1 and SGBS cells pre-treated with GSPE showed a reduction of IL-6 and MCP-1 expression after an inflammatory stimulus. GSPE stimuli alone modulate adipokine (APM1 and LEP) and cytokine (IL-6 and MCP-1) gene expression. GSPE partially inhibited NF-kappaB translocation to the nucleus in both cell lines. These preliminary findings demonstrate that GSPE reduces the expression of IL-6 and MCP-1 and enhances the production of the anti-inflammatory adipokine adiponectin suggesting that may have a beneficial effect on low-grade inflammatory diseases such obesity and type 2 diabetes.
    Full-text · Article · Jul 2009 · Cytokine
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    Agusti Solanas · Gloria Pujol · Antoni Martínez-Ballesté · Josep Maria Mateo-Sanz
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    ABSTRACT: Protecting personal data is essential to guarantee the rule of law1. Due to the new Information and Communication Technologies (ICTs) unprecedented amounts of personal data can be stored and analysed. Thus, if the proper measures are not taken, individual privacy could be in jeopardy. Being the aim to protect individual privacy, a great variety of statistical dis- closure control (SDC) techniques has been proposed. Amongst many others, k-anonymity is a promising property that, if properly achieved, can help protect individual privacy. In this paper, we propose a new post-processing method that can be applied after a k-anonymity algo- rithm, being the aim to lessen the errors resulting from the aggregation of data. We show that our method can be extended to work with many other SDC techniques and we provide some experimental results which em- phasise the usefulness of our proposal.
    Full-text · Conference Paper · Mar 2008
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    ABSTRACT: Microaggregation is a technique used to protect privacy in databases and location-based services. We propose a new hybrid technique for multivariate microaggregation. Our technique combines a heuristic yielding fixed-size groups and a genetic algorithm yielding variable-sized groups. Fixed-size heuristics are fast and able to deal with large data sets, but they sometimes are far from optimal in terms of the information loss inflicted. On the other hand, the genetic algorithm obtains very good results (i.e. optimal or near optimal), but it can only cope with very small data sets. Our technique leverages the advantages of both types of heuristics and avoids their shortcomings. First, it partitions the data set into a number of groups by using a fixed-size heuristic. Then, it optimizes the partitions by means of the genetic algorithm. As an outcome of this mixture of heuristics, we obtain a technique that improves the results of the fixed-size heuristic in large data sets.
    Full-text · Conference Paper · Apr 2007