Quid Pro Quo: A Mechanism for Fair Collaboration in Networked Systems

Collaboration may be understood as the execution of coordinated tasks (in the most general sense) by groups of users, who cooperate for achieving a common goal. Collaboration is a fundamental assumption and requirement for the correct operation of many communication systems. The main challenge when creating collaborative systems in a decentralized manner is dealing with the fact that users may behave in selfish ways, trying to obtain the benefits of the tasks but without participating in their execution. In this context, Game Theory has been instrumental to model collaborative systems and the task allocation problem, and to design mechanisms for optimal allocation of tasks. In this paper, we revise the classical assumptions and propose a new approach to this problem. First, we establish a system model based on heterogenous nodes (users, players), and propose a basic distributed mechanism so that, when a new task appears, it is assigned to the most suitable node. The classical technique for compensating a node that executes a task is the use of payments (which in most networks are hard or impossible to implement). Instead, we propose a distributed mechanism for the optimal allocation of tasks without payments. We prove this mechanism to be robust event in the presence of independent selfish or rationally limited players. Additionally, our model is based on very weak assumptions, which makes the proposed mechanisms susceptible to be implemented in networked systems (e.g., the Internet).Comment: 23 pages, 5 figures, 3 algorithm

Overview of a framework to hypermedia process modeling

In this work, we discuss aspects of a framework to support the understanding and the improvement in hypermedia development processes. The framework is built taking into account two modeling approaches and four domain levels. The modeling approaches are called prescriptive and descriptive respectively, and the domain layers are called, namely, enactment, customization, representation, and reuse/knowledge domains. We feed a potential project regarding this framework by applying a mixture of expression and analysis-oriented descriptive process modeling strategy, and expression, analysis and guided-oriented prescriptive process modeling strategy. That is, the actual or desired entities (process, artifact, and resource) are just described, represented, and analyzed in a somewhat formal way. This potentially allows us to understand, communicate, guide and improve different aspects in hypermedia development projects. Ultimately, we summarize some techniques and mechanisms for prescriptive and descriptive software modeling customized to the hypermedia domain. In addition, we present in-progress researchs and developments.Ingeniería de SoftwareRed de Universidades con Carreras en Informática (RedUNCI

Building hypermedia artifacts by the systematic use of the flexible process model

Most of the current hypermedia model life cycles focus in analysis and design issues, ignoring crucial tasks and activities of hypermedia projects. Others do not take care of basic Software Engineering concepts such as planning, physical and logical modeling, validation and quality assurance, among other issues. In this paper we propose an integrated software process model, called Flexible Process Model, useful in building hypermedia artifacts. This strategy, when instanciated in a specific project, implies a systematic use of model-based constructors, both logical and physical models. The main benefits of this process model are: a) it covers all the principal phases and tasks of a hypermedia project; b) this clear break down can contribute fairly to project planning and can help to establish milestones and metrics; c) it fosters a positive balance by a systematic use of logical and physical modeling; d) it facilitates human communication; e) it promote process improvement and standardization. Therefore, we will discuss and represent, in a medium level of granularity, the phases, tasks and activities, mainly in the dynamic modeling phase. Also we will present some perspectives, stressing the functional, methodological and behavioral perspectives of the three-phased Flexible Process Model. Finally, we will discuss related works and concluding remarks.Eje: Ingeniería de software. Bases de datosRed de Universidades con Carreras en Informática (RedUNCI

Calcium silicates synthesised from industrial residues with the ability for CO2 sequestration

This work explored several synthesis routes to obtain calcium silicates from different calcium-rich and silica-rich industrial residues. Larnite, wollastonite and calcium silicate chloride were successfully synthesised with moderate heat treatments below standard temperatures. These procedures help to not only conserve natural resources, but also to reduce the energy requirements and CO2 emissions. In addition, these silicates have been successfully tested as carbon dioxide sequesters, to enhance the viability of CO2 mineral sequestration technologies using calcium-rich industrial by-products as sequestration agents. Two different carbon sequestration experiments were performed under ambient conditions. Static experiments revealed carbonation efficiencies close to 100% and real-time resolved experiments characterised the dynamic behaviour and ability of these samples to reduce the CO2 concentration within a mixture of gases. The CO2 concentration was reduced up to 70%, with a carbon fixation dynamic ratio of 3.2 mg CO2 per g of sequestration agent and minute. Our results confirm the suitability of the proposed synthesis routes to synthesise different calcium silicates recycling industrial residues, being therefore energetically more efficient and environmentally friendly procedures for the cement industry.Ministerio de Ciencia e Innovación CIT-440000-09-0

Specifying quality characteristics and attributes for E-Learning sites

Education involves a continuous process of exploration, acquisition, organization, integration and delivery of information and knowledge. In recent years, e-learning sites and applications have exponentially started to grow, being a central phenomenon for the industry and education fields. Key factors for the present and future success of these applications and organizations are, on one hand, the fulfillment of technological standards for e-learning environments, and, on the other hand, the utilization of well-defined development processes and the production of required quality. One of our current concerns is the quality assessment of e-learning sites and applications. In this paper, a taxonomy of e-learning sites and applications, and ultimately the quality requirements for the Functionality characteristic are thoroughly described, regarding an intentional audience. An evaluation case study for this domain, using the WebQEM (Quality Evaluation Methodology) strategy is being runned.Eje: Tecnología informática aplicada en la EducaciónRed de Universidades con Carreras en Informática (RedUNCI

Atazanavir-Based Therapy Is Associated with Higher Hepatitis C Viral Load in HIV Type 1-Infected Subjects with Untreated Hepatitis C

Comunicación cortaWe assessed the relationship between atazanavir (ATV)-based antiretroviral treatment (ART) and plasma hepatitis C virus (HCV) viral load in a population of HIV/HCV-coinfected patients. HIV/HCV-coinfected patients who received ART based on a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor (NNRTI) were included. Patients were stratified by ART drug [ATV/rtv, lopinavir (LPV/rtv), efavirenz (EFV), nevirapine (NVP), and other PIs], HCV genotype (1/4 and 2/3), and IL28B genotype (CC and non-CC). The Kruskal-Wallis test and chi-squared test were used to compare continuous and categorical variables, respectively. Multivariate analysis consisted of a stepwise linear regression analysis. Six hundred and forty-nine HIV/HCV-coinfected patients were included. HCV genotype 1/4 patients who received ATV had higher HCV RNA levels [6.57 (5.9-6.8) log IU/ml] than those who received LPV [6.1 (5.5-6.5) log IU/ml], EFV [6.1 (5.6-6.4) log IU/ml], NVP [5.8 (5.5-5.9) log IU/ml], or other PIs [6.1 (5.7-6.4) log IU/ml] (p=0.014). This association held for the IL28B genotype (CC versus non-CC). The association was not found in patients carrying HCV genotypes 2/3. The linear regression model identified the IL28B genotype and ATV use as independent factors associated with HCV RNA levels. ATV-based therapy may be associated with a higher HCV RNA viral load in HIV/HCV-coinfected patients

Transforming a Business and Information Need Goals’ Ontology into a Formal Specification useful for a Strategy Pattern Recommender System

From a computer science point of view, ontologies are aimed at getting knowledge from a certain domain and providing a consensual understanding of it. In the conceptualization stage, ontologies can be represented by means of UML models. However, UML models are not semantically machine processable. Therefore, during the implementation stage, ontologies expressed as UML models should be translated into formal languages, which allow inferring the ontology. In this work, we present the ontology transformation made from an UML conceptual specification to an OWL formal specification for the quality evaluation domain. This ontology represents concepts and relationships related with goals (both business and information need goals) at different organizational levels in addition to projects, strategies and strategy patterns, which help to achieve specific evaluation goal purposes. The final aim of the transformation is to have a shared knowledge about evaluation goals and strategy patterns that permit to instantiate the suitable strategy to carry out goal purposes. This will allow us to develop a strategy pattern recommender system, which can be useful during the strategy selection process when implementing quality measurement and evaluation projects.Sociedad Argentina de Informática e Investigación Operativ

Transforming a Business and Information Need Goals’ Ontology into a Formal Specification useful for a Strategy Pattern Recommender System

From a computer science point of view, ontologies are aimed at getting knowledge from a certain domain and providing a consensual understanding of it. In the conceptualization stage, ontologies can be represented by means of UML models. However, UML models are not semantically machine processable. Therefore, during the implementation stage, ontologies expressed as UML models should be translated into formal languages, which allow inferring the ontology. In this work, we present the ontology transformation made from an UML conceptual specification to an OWL formal specification for the quality evaluation domain. This ontology represents concepts and relationships related with goals (both business and information need goals) at different organizational levels in addition to projects, strategies and strategy patterns, which help to achieve specific evaluation goal purposes. The final aim of the transformation is to have a shared knowledge about evaluation goals and strategy patterns that permit to instantiate the suitable strategy to carry out goal purposes. This will allow us to develop a strategy pattern recommender system, which can be useful during the strategy selection process when implementing quality measurement and evaluation projects.Sociedad Argentina de Informática e Investigación Operativ

Extending the Conceptual Base for a Holistic Quality Evaluation Approach

For software organizations often performing measurement, evaluation (ME), and even change/improvement (MEC) projects, a wellestablished quality evaluation approach can be useful. In this direction, we have developed a holistic quality evaluation approach whose architecture is based on two pillars, namely: a quality multi-view modeling framework, and ME/MEC integrated strategies. In this paper, we specify the conceptual base for the former pillar. Specifically, we specify an ontology of quality views documenting its main terms, properties and relationships. Quality views are paramount for selecting evaluation strategies and strategy patterns to be assigned as resources to ME/MEC projects. Also, we show how this ontology is semantically linked with the previously built ME domain ontology.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Transforming a Business and Information Need Goals’ Ontology into a Formal Specification useful for a Strategy Pattern Recommender System

From a computer science point of view, ontologies are aimed at getting knowledge from a certain domain and providing a consensual understanding of it. In the conceptualization stage, ontologies can be represented by means of UML models. However, UML models are not semantically machine processable. Therefore, during the implementation stage, ontologies expressed as UML models should be translated into formal languages, which allow inferring the ontology. In this work, we present the ontology transformation made from an UML conceptual specification to an OWL formal specification for the quality evaluation domain. This ontology represents concepts and relationships related with goals (both business and information need goals) at different organizational levels in addition to projects, strategies and strategy patterns, which help to achieve specific evaluation goal purposes. The final aim of the transformation is to have a shared knowledge about evaluation goals and strategy patterns that permit to instantiate the suitable strategy to carry out goal purposes. This will allow us to develop a strategy pattern recommender system, which can be useful during the strategy selection process when implementing quality measurement and evaluation projects.Sociedad Argentina de Informática e Investigación Operativ