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Papers by cesar andres

This paper presents a formal framework to perform passive testing of service-oriented systems. Ou... more This paper presents a formal framework to perform passive testing of service-oriented systems. Our approach uses the historical interaction files between web services to check the absence of faults. It uses a set of properties, that we call invariants, to represent the most relevant expected behavior of the web services under test. Intuitively, an invariant expresses the fact that each time the system under test performs a given sequence of actions, it must exhibit a behavior reflected in the invariant. Invariants can be defined from a local point of view, that is, to check properties of isolated web services, and from a global point of view, that is, to check web service interaction properties. In order to increase applicability and adaption to a real environment, we assume that we do not have a global log. We show how to use local logs (recorded in each web service) in order to check local properties and how to combine them in order to check global properties.

Autorizo a reprodução e divulgação total ou parcial deste trabalho, por qualquer meio convenciona... more Autorizo a reprodução e divulgação total ou parcial deste trabalho, por qualquer meio convencional ou eletrônico, para fins de estudo e pesquisa, desde que citada a fonte ARIAS, C. A. D. Production processes of heterologous mCherry protein by Chlamydomonas reinhardtii. 2017. 111f. Tese (Doutorado)

The scFv antibody fragment was expressed in the recombinant yeast Pichia pastoris by using AOX1 p... more The scFv antibody fragment was expressed in the recombinant yeast Pichia pastoris by using AOX1 promoter, in the presence of methanol, as carbon source and as a model for expression. This antibody is considered as a possible alternative for the diagnosis and treatment of atherosclerosis. An initial study was conducted in the production of the antibody fragment and the growth of yeast with two different work benches, varying the carbon source (glucose and glycerol). The results showed that the maximum cell concentrations, and the best production of antibody, were achieved with maintained working stock with glycerol as carbon source and preservation. Subsequently, a study was conducted in shaker and bioreactor, from a 2 3 complete factorial design, in which the variables studied were time induction (24, 28 and 32 hours), temperature induction (10, 20 and 30°C), and concentration of the inducer (methanol 0.5, 1.0 and 1.5%) on the response variable production of the antibody fragment. The only variable that had a statistically significant effect, with a confidence level of 95%, was the inducer concentration for the two production systems. The best yields of the antibody fragment were of 27.8 mg/L for the shaker and 41.3 mg/L for the bioreactor. The third study was to assess the production of antibody fragment into the shaker with the yeast at different carbon sources (sucrose, glycerol, glucose and sucrose/glucose 50%). In this study, the ANOVA analysis did not show statistically significant differences. We conducted planning to improve the quantification of antibody fragment in order to decrease the number of steps to avoid losses in the process. After getting a new protocol for the quantification, we carried out a new study to evaluate the production with different carbon sources. The analysis of the results showed that all carbon sources showed statistically significant effects, among which sucrose obtained the highest yield 93.7 mg/L of antibody fragment. These results were compared and analyzed through a microscope, in which with the observations of the yeast showed that the best antibody production was obtained when the yeast had sizes smaller than 0.895 microns. Next, a study was conducted to determine alternative sources of carbon and nitrogen (rice bran and wheat bran) to produce the antibody fragment in place of casein peptone and casaminoacids as substrates. The highest yield obtained in this case was 27.9 mg/L, when casamino was replaced by the wheat bran. Finally, we evaluated the effect of kLa in yeast growth and production of the antibody fragment scFv, the results showed that the best condition for the growth of the yeast was 96.12 h-1 , on the other hand, the best condition for the production antibody fragment was 12.24 h-1 with a final relation yield of 8.12 mg/L antibody/g/L cell.

Journal of Logical and Algebraic Methods in Programming, 2016

Abstract Software Product Lines modeling improves software development processes by automating sy... more Abstract Software Product Lines modeling improves software development processes by automating system debugging and analysis. The objective of this paper focuses on extending the formal framework SPLA to represent features such as cost objects and comparisons between products in terms of production costs. We illustrate this extension with a practical example by modeling the creation of valid run-lists for Chef, a widely used configuration management tool. Also, we execute our formal specification in a distributed system using SCOOP and we provide strategies to optimize the effort required to compute a SPLA term.

Electronic Proceedings in Theoretical Computer Science, 2012

ABSTRACT This volume contains the proceedings of the 2nd WorkShop on Formal Methods in the Develo... more ABSTRACT This volume contains the proceedings of the 2nd WorkShop on Formal Methods in the Development of Software (WS-FMDS 2012). The workshop was held in Paris, France on August 30th, 2012 as a satellite event to the 18th International Symposium on Formal Methods (FM-2012). The aim of WS-FMDS 2012 is to provide a forum for researchers who are interested in the application of formal methods on systems which are being developing with a software methodology. In particular, this workshop is intended to bring together scientists and practitioners who are active in the area of formal methods and interested in exchanging their experiences in the industrial usage of these methods. This workshop also strives to promote research and development for the improvement of formal methods and tools for industrial applications.

Uranium, Mining and Hydrogeology, 2008

ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays... more ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays mines are closed and environmental monitoring is conducted by the former operator (AREVA-NC) under the control of the French administration. In the year 2006, the French safety authority board has created a pluralist expert group (GEP) that enjoin experts, stake holders and government representatives, to improve the environment protection concerning the process of uranium mines closure and rehabilitation. A part of the work is devoted to the study of mines as radionuclides sources and to the transport of radionuclides in the environment. According to regulation, site waters must be collected, and when necessary treated, before being released into the environment. Those waters constitute the main vector of radionuclides transportation. Several previous studies revealed an accumulation of radionuclides in lake sediments downstream mines inputs. This phenomenon is illustrated on the Ritord watershed; in an artificial lake created only few kilometres downstream one of the main treated mine waters release. To identify the mechanisms of the radionuclides accumulation in sediments, the GEP has investigated, through the environmental survey database, the water treatment efficiency and the behaviour of 238U and 226Ra from mines to the river. It concluded that a part of particles containing 226Ra produced in the water treatment station is not trapped but released to the river. The reduction of the water flow velocity where the stream enters the lake leads to the particles deposition. As a consequence, the water treatment station has been modified to reduce the particle outflow. The uranium and radium content on particulate, colloidal and dissolve fractions were then investigated over a year all along the treatment process as well as downstream the water release point. Results of this specific study will be pre- sented.

2013 IEEE 10th International Conference on High Performance Computing and Communications & 2013 IEEE International Conference on Embedded and Ubiquitous Computing, 2013

ABSTRACT In this paper we present a modeling formal framework to specify nets of virtual organiza... more ABSTRACT In this paper we present a modeling formal framework to specify nets of virtual organizations. In these nets are defined not only the employees that are working in each organization but also there are included some properties that allow to ensure the security. This framework makes it easier to write and understand the security properties behavior. In addition to the syntax and semantics we provide a running example of two organizations to understand this approach.

Lecture Notes in Computer Science, 2010

In this paper it is presented the features and behavior of the tutoring-training system MACRO-SYS... more In this paper it is presented the features and behavior of the tutoring-training system MACRO-SYS. This system allows students to simulate experiments with complex macroeconomic environments. Users have to show their knowledge level by solving the proposed exercises. These exercises represent different economist behaviours. A big advantage of our system is that it allows students to be part of the simulation, interacting and modifying the behavior (parameters), both in the short and long-term, of a real scale economy. If MACRO-SYS detects that the simulated values are strongly deviating from the expected pattern, it will provide hints to the student so that she can change some parameters and bring the economy to the correct (according to the assignment) behavior. Finally, let us remark that, in contrast with most economic models, our system takes into account a huge amount of parameters in order to compute the current state of the economy.

Access control in Multi-Organization Environment (MOE) is a critical issue. Several access contro... more Access control in Multi-Organization Environment (MOE) is a critical issue. Several access control models need some improvements to be used in such environment where the behaviors of the users and the organizations may change during the collaboration. In similar environments, the use of trust management with an access control model is recommended. It is worth to mention that trust allow us to increase the security of the system, due to the fact it is dynamic, so it let us represent at runtime changes in the behavior of the players. In this paper, we aim to define trust of users and organizations in MOE. In these models, the initial valuation of the trust is crucial, in the sense that all the trust framework will depend on these initial values. In particular, in MOE these values should be computed using not only the experience of the users with an organization but also the experience of an organization with another organizations. However, the combination of these values normally is not an easy task. Therefore, in this paper we propose an algorithm that uses fuzzy logic to manage this information. In particular, this methodology allows us to extract the initial set of trust values of a MOE taking into account past experiences.

Conté: Piramide bautismal de Doña Maria Teresa Bibliana de Austria / por Don Josef Pellicer Tobar... more Conté: Piramide bautismal de Doña Maria Teresa Bibliana de Austria / por Don Josef Pellicer Tobar. - P. I-XIVinyeta a portFiletsNotes a peu de p. - ReclamsSign.: A-D8, E

Uranium, Mining and Hydrogeology, 2008

ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays... more ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays mines are closed and environmental monitoring is conducted by the former operator (AREVA-NC) under the control of the French administration. In the year 2006, the French safety authority board has created a pluralist expert group (GEP) that enjoin experts, stake holders and government representatives, to improve the environment protection concerning the process of uranium mines closure and rehabilitation. A part of the work is devoted to the study of mines as radionuclides sources and to the transport of radionuclides in the environment. According to regulation, site waters must be collected, and when necessary treated, before being released into the environment. Those waters constitute the main vector of radionuclides transportation. Several previous studies revealed an accumulation of radionuclides in lake sediments downstream mines inputs. This phenomenon is illustrated on the Ritord watershed; in an artificial lake created only few kilometres downstream one of the main treated mine waters release. To identify the mechanisms of the radionuclides accumulation in sediments, the GEP has investigated, through the environmental survey database, the water treatment efficiency and the behaviour of 238U and 226Ra from mines to the river. It concluded that a part of particles containing 226Ra produced in the water treatment station is not trapped but released to the river. The reduction of the water flow velocity where the stream enters the lake leads to the particles deposition. As a consequence, the water treatment station has been modified to reduce the particle outflow. The uranium and radium content on particulate, colloidal and dissolve fractions were then investigated over a year all along the treatment process as well as downstream the water release point. Results of this specific study will be pre- sented.

The New Uranium Mining Boom, 2011

Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are... more Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are closed and restored. Rehabilitation operations were devoted to assure the stability of land and infrastructures as well as to collect mine water and keep under control the radionuclide release into watersheds. Environmental monitoring is conducted by the operator (Areva-NC) under the control of the French administration. The present paper describes the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of. This methodology and the corresponding modeling approach then proved to be adaptable to other tailings deposit sites.

The New Uranium Mining Boom, 2011

Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are... more Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are closed and restored. Rehabilitation operations were devoted to assure the stability of land and infrastructures as well as to collect mine water and keep under control the radionuclide release into watersheds. Environmental monitoring is conducted by the operator (Areva-NC) under the control of the French administration. The present paper describes the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of. This methodology and the corresponding modeling approach then proved to be adaptable to other tailings deposit sites.

2012 7th International Conference on Risks and Security of Internet and Systems (CRiSIS), 2012

ABSTRACT A Multi-Organization Environment is composed of several players that depend on each othe... more ABSTRACT A Multi-Organization Environment is composed of several players that depend on each other for resources and services. In order to manage the security of the exchange process we introduce the concept of trust. We show how this aspect of the cooperative work allows us to increase some security aspects. In particular, we provide a framework where the concepts of trust requirement and trust evaluation play important roles for defining trust vectors. These vectors evaluate a set of requirements, under some conditions, and provide a degree of confidence. In our framework we consider two different types of vectors. On the one hand a vector that relates a user to an organization and on the other hand a vector that links two organizations. Finally we show how these vectors are evaluated and shared among the different organizations, and how we combine the provided trust information in order to enhance the security.

Lecture Notes in Computer Science, 2008

We present a formal method to determine whether there exist living creatures in a given computati... more We present a formal method to determine whether there exist living creatures in a given computational environment. Our proposal is based on studying the evolution of the entropy of the studied system. In particular, we check whether there exist entities decreasing the ...

Third International Conference on Systems (icons 2008), 2008

In this paper we present a new model to formally represent complex information systems. This new ... more In this paper we present a new model to formally represent complex information systems. This new formalism is very suitable to specify time requirements (both time consumption due to the performance of tasks and timeouts) as well as to represent data communication among different components of a system. In addition to provide the theoretical framework, we show how this formalism, based on finite state machines, has been used as the basis to develop a real information system. This exercise convinced us that a formal approach to develop complex systems can facilitate some of the development phases. In particular, the testing phase, more precisely, how to choose which tests to apply, is simplified since tests are automatically extracted from the specification.

This paper presents a formal framework to perform passive testing of service-oriented systems. Ou... more This paper presents a formal framework to perform passive testing of service-oriented systems. Our approach uses the historical interaction files between web services to check the absence of faults. It uses a set of properties, that we call invariants, to represent the most relevant expected behavior of the web services under test. Intuitively, an invariant expresses the fact that each time the system under test performs a given sequence of actions, it must exhibit a behavior reflected in the invariant. Invariants can be defined from a local point of view, that is, to check properties of isolated web services, and from a global point of view, that is, to check web service interaction properties. In order to increase applicability and adaption to a real environment, we assume that we do not have a global log. We show how to use local logs (recorded in each web service) in order to check local properties and how to combine them in order to check global properties.

Autorizo a reprodução e divulgação total ou parcial deste trabalho, por qualquer meio convenciona... more Autorizo a reprodução e divulgação total ou parcial deste trabalho, por qualquer meio convencional ou eletrônico, para fins de estudo e pesquisa, desde que citada a fonte ARIAS, C. A. D. Production processes of heterologous mCherry protein by Chlamydomonas reinhardtii. 2017. 111f. Tese (Doutorado)

The scFv antibody fragment was expressed in the recombinant yeast Pichia pastoris by using AOX1 p... more The scFv antibody fragment was expressed in the recombinant yeast Pichia pastoris by using AOX1 promoter, in the presence of methanol, as carbon source and as a model for expression. This antibody is considered as a possible alternative for the diagnosis and treatment of atherosclerosis. An initial study was conducted in the production of the antibody fragment and the growth of yeast with two different work benches, varying the carbon source (glucose and glycerol). The results showed that the maximum cell concentrations, and the best production of antibody, were achieved with maintained working stock with glycerol as carbon source and preservation. Subsequently, a study was conducted in shaker and bioreactor, from a 2 3 complete factorial design, in which the variables studied were time induction (24, 28 and 32 hours), temperature induction (10, 20 and 30°C), and concentration of the inducer (methanol 0.5, 1.0 and 1.5%) on the response variable production of the antibody fragment. The only variable that had a statistically significant effect, with a confidence level of 95%, was the inducer concentration for the two production systems. The best yields of the antibody fragment were of 27.8 mg/L for the shaker and 41.3 mg/L for the bioreactor. The third study was to assess the production of antibody fragment into the shaker with the yeast at different carbon sources (sucrose, glycerol, glucose and sucrose/glucose 50%). In this study, the ANOVA analysis did not show statistically significant differences. We conducted planning to improve the quantification of antibody fragment in order to decrease the number of steps to avoid losses in the process. After getting a new protocol for the quantification, we carried out a new study to evaluate the production with different carbon sources. The analysis of the results showed that all carbon sources showed statistically significant effects, among which sucrose obtained the highest yield 93.7 mg/L of antibody fragment. These results were compared and analyzed through a microscope, in which with the observations of the yeast showed that the best antibody production was obtained when the yeast had sizes smaller than 0.895 microns. Next, a study was conducted to determine alternative sources of carbon and nitrogen (rice bran and wheat bran) to produce the antibody fragment in place of casein peptone and casaminoacids as substrates. The highest yield obtained in this case was 27.9 mg/L, when casamino was replaced by the wheat bran. Finally, we evaluated the effect of kLa in yeast growth and production of the antibody fragment scFv, the results showed that the best condition for the growth of the yeast was 96.12 h-1 , on the other hand, the best condition for the production antibody fragment was 12.24 h-1 with a final relation yield of 8.12 mg/L antibody/g/L cell.

Journal of Logical and Algebraic Methods in Programming, 2016

Abstract Software Product Lines modeling improves software development processes by automating sy... more Abstract Software Product Lines modeling improves software development processes by automating system debugging and analysis. The objective of this paper focuses on extending the formal framework SPLA to represent features such as cost objects and comparisons between products in terms of production costs. We illustrate this extension with a practical example by modeling the creation of valid run-lists for Chef, a widely used configuration management tool. Also, we execute our formal specification in a distributed system using SCOOP and we provide strategies to optimize the effort required to compute a SPLA term.

Electronic Proceedings in Theoretical Computer Science, 2012

ABSTRACT This volume contains the proceedings of the 2nd WorkShop on Formal Methods in the Develo... more ABSTRACT This volume contains the proceedings of the 2nd WorkShop on Formal Methods in the Development of Software (WS-FMDS 2012). The workshop was held in Paris, France on August 30th, 2012 as a satellite event to the 18th International Symposium on Formal Methods (FM-2012). The aim of WS-FMDS 2012 is to provide a forum for researchers who are interested in the application of formal methods on systems which are being developing with a software methodology. In particular, this workshop is intended to bring together scientists and practitioners who are active in the area of formal methods and interested in exchanging their experiences in the industrial usage of these methods. This workshop also strives to promote research and development for the improvement of formal methods and tools for industrial applications.

Uranium, Mining and Hydrogeology, 2008

ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays... more ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays mines are closed and environmental monitoring is conducted by the former operator (AREVA-NC) under the control of the French administration. In the year 2006, the French safety authority board has created a pluralist expert group (GEP) that enjoin experts, stake holders and government representatives, to improve the environment protection concerning the process of uranium mines closure and rehabilitation. A part of the work is devoted to the study of mines as radionuclides sources and to the transport of radionuclides in the environment. According to regulation, site waters must be collected, and when necessary treated, before being released into the environment. Those waters constitute the main vector of radionuclides transportation. Several previous studies revealed an accumulation of radionuclides in lake sediments downstream mines inputs. This phenomenon is illustrated on the Ritord watershed; in an artificial lake created only few kilometres downstream one of the main treated mine waters release. To identify the mechanisms of the radionuclides accumulation in sediments, the GEP has investigated, through the environmental survey database, the water treatment efficiency and the behaviour of 238U and 226Ra from mines to the river. It concluded that a part of particles containing 226Ra produced in the water treatment station is not trapped but released to the river. The reduction of the water flow velocity where the stream enters the lake leads to the particles deposition. As a consequence, the water treatment station has been modified to reduce the particle outflow. The uranium and radium content on particulate, colloidal and dissolve fractions were then investigated over a year all along the treatment process as well as downstream the water release point. Results of this specific study will be pre- sented.

2013 IEEE 10th International Conference on High Performance Computing and Communications & 2013 IEEE International Conference on Embedded and Ubiquitous Computing, 2013

ABSTRACT In this paper we present a modeling formal framework to specify nets of virtual organiza... more ABSTRACT In this paper we present a modeling formal framework to specify nets of virtual organizations. In these nets are defined not only the employees that are working in each organization but also there are included some properties that allow to ensure the security. This framework makes it easier to write and understand the security properties behavior. In addition to the syntax and semantics we provide a running example of two organizations to understand this approach.

Lecture Notes in Computer Science, 2010

In this paper it is presented the features and behavior of the tutoring-training system MACRO-SYS... more In this paper it is presented the features and behavior of the tutoring-training system MACRO-SYS. This system allows students to simulate experiments with complex macroeconomic environments. Users have to show their knowledge level by solving the proposed exercises. These exercises represent different economist behaviours. A big advantage of our system is that it allows students to be part of the simulation, interacting and modifying the behavior (parameters), both in the short and long-term, of a real scale economy. If MACRO-SYS detects that the simulated values are strongly deviating from the expected pattern, it will provide hints to the student so that she can change some parameters and bring the economy to the correct (according to the assignment) behavior. Finally, let us remark that, in contrast with most economic models, our system takes into account a huge amount of parameters in order to compute the current state of the economy.

Access control in Multi-Organization Environment (MOE) is a critical issue. Several access contro... more Access control in Multi-Organization Environment (MOE) is a critical issue. Several access control models need some improvements to be used in such environment where the behaviors of the users and the organizations may change during the collaboration. In similar environments, the use of trust management with an access control model is recommended. It is worth to mention that trust allow us to increase the security of the system, due to the fact it is dynamic, so it let us represent at runtime changes in the behavior of the players. In this paper, we aim to define trust of users and organizations in MOE. In these models, the initial valuation of the trust is crucial, in the sense that all the trust framework will depend on these initial values. In particular, in MOE these values should be computed using not only the experience of the users with an organization but also the experience of an organization with another organizations. However, the combination of these values normally is not an easy task. Therefore, in this paper we propose an algorithm that uses fuzzy logic to manage this information. In particular, this methodology allows us to extract the initial set of trust values of a MOE taking into account past experiences.

Conté: Piramide bautismal de Doña Maria Teresa Bibliana de Austria / por Don Josef Pellicer Tobar... more Conté: Piramide bautismal de Doña Maria Teresa Bibliana de Austria / por Don Josef Pellicer Tobar. - P. I-XIVinyeta a portFiletsNotes a peu de p. - ReclamsSign.: A-D8, E

Uranium, Mining and Hydrogeology, 2008

ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays... more ABSTRACT Uranium has been mined in the Limousin area (France) until the end of the 90’s. Nowadays mines are closed and environmental monitoring is conducted by the former operator (AREVA-NC) under the control of the French administration. In the year 2006, the French safety authority board has created a pluralist expert group (GEP) that enjoin experts, stake holders and government representatives, to improve the environment protection concerning the process of uranium mines closure and rehabilitation. A part of the work is devoted to the study of mines as radionuclides sources and to the transport of radionuclides in the environment. According to regulation, site waters must be collected, and when necessary treated, before being released into the environment. Those waters constitute the main vector of radionuclides transportation. Several previous studies revealed an accumulation of radionuclides in lake sediments downstream mines inputs. This phenomenon is illustrated on the Ritord watershed; in an artificial lake created only few kilometres downstream one of the main treated mine waters release. To identify the mechanisms of the radionuclides accumulation in sediments, the GEP has investigated, through the environmental survey database, the water treatment efficiency and the behaviour of 238U and 226Ra from mines to the river. It concluded that a part of particles containing 226Ra produced in the water treatment station is not trapped but released to the river. The reduction of the water flow velocity where the stream enters the lake leads to the particles deposition. As a consequence, the water treatment station has been modified to reduce the particle outflow. The uranium and radium content on particulate, colloidal and dissolve fractions were then investigated over a year all along the treatment process as well as downstream the water release point. Results of this specific study will be pre- sented.

The New Uranium Mining Boom, 2011

Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are... more Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are closed and restored. Rehabilitation operations were devoted to assure the stability of land and infrastructures as well as to collect mine water and keep under control the radionuclide release into watersheds. Environmental monitoring is conducted by the operator (Areva-NC) under the control of the French administration. The present paper describes the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of. This methodology and the corresponding modeling approach then proved to be adaptable to other tailings deposit sites.

The New Uranium Mining Boom, 2011

Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are... more Uranium has been mined in the Limousin area (France) until the end of the 90s. Nowadays mines are closed and restored. Rehabilitation operations were devoted to assure the stability of land and infrastructures as well as to collect mine water and keep under control the radionuclide release into watersheds. Environmental monitoring is conducted by the operator (Areva-NC) under the control of the French administration. The present paper describes the methodology of investigation and the geochemical modeling approach that was developed on the Bellezane mining site where tailings are disposed of. This methodology and the corresponding modeling approach then proved to be adaptable to other tailings deposit sites.

2012 7th International Conference on Risks and Security of Internet and Systems (CRiSIS), 2012

ABSTRACT A Multi-Organization Environment is composed of several players that depend on each othe... more ABSTRACT A Multi-Organization Environment is composed of several players that depend on each other for resources and services. In order to manage the security of the exchange process we introduce the concept of trust. We show how this aspect of the cooperative work allows us to increase some security aspects. In particular, we provide a framework where the concepts of trust requirement and trust evaluation play important roles for defining trust vectors. These vectors evaluate a set of requirements, under some conditions, and provide a degree of confidence. In our framework we consider two different types of vectors. On the one hand a vector that relates a user to an organization and on the other hand a vector that links two organizations. Finally we show how these vectors are evaluated and shared among the different organizations, and how we combine the provided trust information in order to enhance the security.

Lecture Notes in Computer Science, 2008

We present a formal method to determine whether there exist living creatures in a given computati... more We present a formal method to determine whether there exist living creatures in a given computational environment. Our proposal is based on studying the evolution of the entropy of the studied system. In particular, we check whether there exist entities decreasing the ...

Third International Conference on Systems (icons 2008), 2008

In this paper we present a new model to formally represent complex information systems. This new ... more In this paper we present a new model to formally represent complex information systems. This new formalism is very suitable to specify time requirements (both time consumption due to the performance of tasks and timeouts) as well as to represent data communication among different components of a system. In addition to provide the theoretical framework, we show how this formalism, based on finite state machines, has been used as the basis to develop a real information system. This exercise convinced us that a formal approach to develop complex systems can facilitate some of the development phases. In particular, the testing phase, more precisely, how to choose which tests to apply, is simplified since tests are automatically extracted from the specification.