Pablo Basanta Val | Universidad Carlos III de Madrid (original) (raw)

Papers by Pablo Basanta Val

… , IEEE Transactions on, Jan 1, 2011

This paper presents a software framework containing a reconfiguration mechanism that provides rea... more This paper presents a software framework containing a reconfiguration mechanism that provides realtime execution guarantees in intensive media processing consumer electronic devices. Our approach offers real-time guarantees during all of the system operation, i.e., not only during the normal media processing mode but also in the event of reconfigurations (a reconfiguration is a transition among two different system states). This approach enhances the budget scheduling model to provide a time-partition that guarantees the availability of resources during transitions. Results are presented that validate the proposed approach 1 .

Industrial …, Jan 1, 2009

Abstract This paper presents a model for quality-of-service (QoS)-aware service composition in di... more Abstract This paper presents a model for quality-of-service (QoS)-aware service composition in distributed systems with real-time and fault-tolerance requirements. This model can be applied in application domains like, for example, remote monitoring, control and surveillance. Classic approaches to real-time systems do not provide the flexibility and fault-tolerance required in new emerging environments that need to combine a high degree of dynamism with temporal predictability. Our approach addresses these new challenges by ...

Object-Oriented Real- …, Jan 1, 2005

Abstract This paper presents a memory management solution for distributed real-time Java. The pro... more Abstract This paper presents a memory management solution for distributed real-time Java. The proposed model is targeted at distributed applications that require to keep their internal state and that consume a bounded memory size in their operation. The aim is to provide an alternative to the garbage collector for distributed real-time systems and to avoid the penalties it introduces. The approach is based on the usage of scoped memory defined in the real-time specification for Java (RTSJ). Our solution introduces constraints in the ...

This paper describes an approach towards the definition and implementation of a synchronization s... more This paper describes an approach towards the definition and implementation of a synchronization service on top of a remote object model offered by an unicast real-time remote object paradigm. Also an architecture model based on the RTSJ (Real-time Specification for Java) and the distribution middleware RMI (Remote Method Invocation) specifications is proposed in order to give support to the model, defining a convergence layer that manages the underlying resources involved in a master-slave communication through a new API. Finally, preliminary results from an implementation prototype show the feasibility of the model and provide an initial estimation of jitters and the performance of the synchronization service.

On the Move to …, Jan 1, 2004

This paper presents an approach to provide real-time support for Java RMI integrating it with the... more This paper presents an approach to provide real-time support for Java RMI integrating it with the RTSJ memory model to leave out garbage collection. A new construct for remote objects is proposed: the no heap remote object (NhRo). The usage of a NhRo guarantees that memory required to perform a remote invocation (at the server side) does not use heap memory. The aim is to avoid garbage collection in the remote invocation process, improving predictability and memory isolation of Java-based distributed real-time applications. The ...

Abstract Recently, new trends in application development for distributed platforms, such as the c... more Abstract Recently, new trends in application development for distributed platforms, such as the composable services model, attempt to provide more flexibility in system design, deployment and execution. Such trends, and particularly the referred composable services model, can also be beneficial in real-time distributed embedded systems, also providing a means to support more adaptive behaviors, reacting to the execution environment or coping with system reconfiguration. This paper explores a relatively new direction, which is the ...

IEEE Transactions on …, Jan 1, 2010

Current trends in real-time systems identify Java as a new alternative to develop both centralize... more Current trends in real-time systems identify Java as a new alternative to develop both centralized and distributed real-time systems. Many efforts have been devoted to develop the Real-Time Specification for Java (RTSJ), and there is substantial ongoing activity to produce a straightforward and valuable Distributed Real Time Specification for Java (DRTSJ). The current paper provides a contribution to this latter activity defining, from different angles, a synchronous scheduling service aligned with principles of some popular real-time architectures. This service orchestrates the system in such a way that it provides end-toend guarantees in the distributed transactions, guaranteeing their timely execution across the network and nodes. The service is described from two points of view: the system one, characterizing a portable model; and the programmer one, defining a distributed object-oriented implementation of a model based on Real-Time Remote Method Invocation (RTRMI). Finally, it also presents results of an implementation carried out to judge the efficiency of the service, offering a preliminary predictability and performance assessment of a distributed real-time Java technology.

ACM SIGBED Review, Jan 1, 2005

This paper presents an approach towards a framework that enables the composition of real-time app... more This paper presents an approach towards a framework that enables the composition of real-time applications from existing ubiquitous services. This framework allows to announce services (specifying their QoS requirements in terms of real-time parameters, such as Worst Case Execution Time, WCET), to discover services that perform a certain functionality, and to select the set of those discovered services that will be part of the application to be created. Such service set selection is based on the fulfilment of the QoS requirements of the application. The framework supports static composition, i.e., all services required to create an application have to be discovered before launching the whole application. Finally, it is described the composition model used in the framework.

Proceedings of the …, Jan 1, 2006

Abstract One of the main drawbacks of programming with the RTSJ (The Real-time Specification for ... more Abstract One of the main drawbacks of programming with the RTSJ (The Real-time Specification for Java) is probably its special model of references. The restrictions imposed by the assignment and single parent rules constrains the programming model in such a way that it is sometimes more difficult to use than the Java one. The community has faced this problem producing a special and new set of programming paradigms and patterns, designed to be used in collaboration with the region-based model; this enhances the ...

… Oriented Real-Time …, Jan 1, 2008

Abstract Recently, the application domains where the development of systems with temporal guarant... more Abstract Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no longer applicable since it is too pessimistic. Thus, new challenges arise to adapt the current methodologies used in different architectural levels to these new environments. New directions and paradigms are needed to allow combining functional flexibility and dynamism with temporal predictability. The ...

ACM SIGBED Review, Jan 1, 2005

The region-based memory model of The Realtime Specification for Java (RTSJ) is quite rigid, and i... more The region-based memory model of The Realtime Specification for Java (RTSJ) is quite rigid, and it complicates the development of reusable predictable software for large-scale systems. In this paper, we propose an extension to the region model of the RTSJ called AGCMemory (Acyclic Garbage Collected Memory). This extension enables the transparent destruction of floating garbage created during the execution of Java methods. The integration within the memory model of the RTSJ and its automatic memory management algorithm, based on run-time barriers, are described.

ACM Transactions on …, Jan 1, 2010

This paper presents an approach to provide real-time support for Java's Remote Method Invocation ... more This paper presents an approach to provide real-time support for Java's Remote Method Invocation (RMI) and its integration with the RTSJ memory model in order to leave out garbage collection. A new construct for remote objects, named No-heap Remote object (NhRo), is introduced. The usage of a NhRo guarantees that memory required to perform a remote invocation (at the server side) does not use heap-memory. Thus, the aim is to avoid garbage collection in the remote invocation process, improving predictability and memory isolation of distributed Java-based real-time applications. The paper presents the bare model and the main programming patterns which are associated with the NhRo model. Sun RMI implementation has been modified to integrate the NhRo model in both static and dynamic environments.

Object Oriented Real- …, Jan 1, 2008

Abstract Current RTSJ (the real-time specification for Java) threading model is dualized: program... more Abstract Current RTSJ (the real-time specification for Java) threading model is dualized: programmers have to decide between the high predictability offered by its region-based model and the flexibility offered by its garbage-collected model. Up to now, there is not a unique type of thread that offers, in a single entity, the highest predictability, and flexibility together. This lack has serious consequences on the programmer who has to deal with new and sometimes non-trivial mechanisms, such as queues of objects or the no-heap real- ...

2010 10th IEEE …, Jan 1, 2010

Abstract Nowadays, there is a trend in industrial systems towards the use of common-off-the-shelf... more Abstract Nowadays, there is a trend in industrial systems towards the use of common-off-the-shelf (COTS) components to develop applications which interact with open systems. This trend includes among others the use of high-level languages, such as Java, and Internet protocols (TCP-IP, HTTP, and Web Services). However, although many industrial systems use these technologies at their business layers, they are far from offering a homogeneous programming platform in their most internal infrastructures. This paper contributes to ...

… for Future Embedded …, Jan 1, 2005

This paper presents an approach towards a framework that enables the composition of real-time app... more This paper presents an approach towards a framework that enables the composition of real-time applications from existing ubiquitous services. This framework allows to announce services (specifying their QoS requirements in terms of real-time parameters, such as Worst Case Execution Time, WCET), to discover services that perform a certain functionality, and to select the set of those discovered services that will be part of the application to be created. Such service set selection is based on the fulfilment of the QoS requirements of the application. The framework supports static composition, i.e., all services required to create an application have to be discovered before launching the whole application.

… Conference on Advanced …, Jan 1, 2009

Abstract Current generation of distributed real-time systems requires more flexibility and the ab... more Abstract Current generation of distributed real-time systems requires more flexibility and the ability of changing its behaviour at run time. This paper presents a model and an algorithm for QoS-aware service composition in distributed systems with real-time requirements. This model is applicable in application domains where temporal guarantees and flexibility are needed, such as remote monitoring, control or surveillance. Our approach combines concepts from the service oriented paradigm and distributed real-time systems. We ...

Concurrency and …, Jan 1, 2011

The proliferation of a new generation of distributed real-time embedded systems (DRE) characteriz... more The proliferation of a new generation of distributed real-time embedded systems (DRE) characterized by special restrictions on its storage capacities, its available computation time, and the messages they can send through the network suggests a comprehensive redesign of the current distribution infrastructure in order to tune its performance. In this changing panorama, the paper concerns one of the protocols, Java's Remote Method Protocol (JRMP), used nowadays to interconnect different nodes of a distributed Java system, and explores the cost of integrating an improved protocol-level multiplexing strategy in the context of an end-to-end remote invocation. The new multiplexing strategy helps middleware manage more efficiently unscheduled invocations that appear at runtime generated from a certain client node, especially in cases where preallocation of resources or dimensioning for the worst-case are techniques not plausible. To this end, the paper examines an alternative based on the definition of a new subprotocol, called ConnectionLess, which offers built-in multiplexing facilities for distributed Java applications. The performance of the new subprotocol is compared against the three already defined by JRMP (namely SingleOp, Stream, and Multiplex), taking into consideration parameters such as memory consumed in the Java's virtual machine and end-to-end response times. JAVA'S REMOTE METHOD PROTOCOL 1241 Figure 4. First remote invocation with each JRMP subprotocol.

New Technologies of …, Jan 1, 2010

Abstract Networked applications structured as a collection of interconnected services offer high ... more Abstract Networked applications structured as a collection of interconnected services offer high flexibility. In this context, services arc functional parts that receive and send messages in a distributed environment. This structure is especially interesting for multimedia/video applications due to their natural mapping to a graph-based structure. In this paper, a component model for the implementation of services is provided. The goal is to obtain services developed with a homogeneous structure to case interoperability. The proposed ...

2009 International Conference on …, Jan 1, 2009

Abstract To support real-time properties, mobile real-time operating system (RTOS) platforms have... more Abstract To support real-time properties, mobile real-time operating system (RTOS) platforms have added to their classical cyclic executive model more flexible concurrency paradigms based on threads and preemptive priority-based scheduling algorithms. However, in newer mobile RTOS, the concurrency model is also going back to prior cooperative multi-tasking models similar to cyclic executives (based on active objects). This paper presents the concurrency model of a very popular mobile RTOS platform, as ...

… , IEEE Transactions on, Jan 1, 2011

This paper presents a software framework containing a reconfiguration mechanism that provides rea... more This paper presents a software framework containing a reconfiguration mechanism that provides realtime execution guarantees in intensive media processing consumer electronic devices. Our approach offers real-time guarantees during all of the system operation, i.e., not only during the normal media processing mode but also in the event of reconfigurations (a reconfiguration is a transition among two different system states). This approach enhances the budget scheduling model to provide a time-partition that guarantees the availability of resources during transitions. Results are presented that validate the proposed approach 1 .

Industrial …, Jan 1, 2009

Abstract This paper presents a model for quality-of-service (QoS)-aware service composition in di... more Abstract This paper presents a model for quality-of-service (QoS)-aware service composition in distributed systems with real-time and fault-tolerance requirements. This model can be applied in application domains like, for example, remote monitoring, control and surveillance. Classic approaches to real-time systems do not provide the flexibility and fault-tolerance required in new emerging environments that need to combine a high degree of dynamism with temporal predictability. Our approach addresses these new challenges by ...

Object-Oriented Real- …, Jan 1, 2005

Abstract This paper presents a memory management solution for distributed real-time Java. The pro... more Abstract This paper presents a memory management solution for distributed real-time Java. The proposed model is targeted at distributed applications that require to keep their internal state and that consume a bounded memory size in their operation. The aim is to provide an alternative to the garbage collector for distributed real-time systems and to avoid the penalties it introduces. The approach is based on the usage of scoped memory defined in the real-time specification for Java (RTSJ). Our solution introduces constraints in the ...

This paper describes an approach towards the definition and implementation of a synchronization s... more This paper describes an approach towards the definition and implementation of a synchronization service on top of a remote object model offered by an unicast real-time remote object paradigm. Also an architecture model based on the RTSJ (Real-time Specification for Java) and the distribution middleware RMI (Remote Method Invocation) specifications is proposed in order to give support to the model, defining a convergence layer that manages the underlying resources involved in a master-slave communication through a new API. Finally, preliminary results from an implementation prototype show the feasibility of the model and provide an initial estimation of jitters and the performance of the synchronization service.

On the Move to …, Jan 1, 2004

This paper presents an approach to provide real-time support for Java RMI integrating it with the... more This paper presents an approach to provide real-time support for Java RMI integrating it with the RTSJ memory model to leave out garbage collection. A new construct for remote objects is proposed: the no heap remote object (NhRo). The usage of a NhRo guarantees that memory required to perform a remote invocation (at the server side) does not use heap memory. The aim is to avoid garbage collection in the remote invocation process, improving predictability and memory isolation of Java-based distributed real-time applications. The ...

Abstract Recently, new trends in application development for distributed platforms, such as the c... more Abstract Recently, new trends in application development for distributed platforms, such as the composable services model, attempt to provide more flexibility in system design, deployment and execution. Such trends, and particularly the referred composable services model, can also be beneficial in real-time distributed embedded systems, also providing a means to support more adaptive behaviors, reacting to the execution environment or coping with system reconfiguration. This paper explores a relatively new direction, which is the ...

IEEE Transactions on …, Jan 1, 2010

Current trends in real-time systems identify Java as a new alternative to develop both centralize... more Current trends in real-time systems identify Java as a new alternative to develop both centralized and distributed real-time systems. Many efforts have been devoted to develop the Real-Time Specification for Java (RTSJ), and there is substantial ongoing activity to produce a straightforward and valuable Distributed Real Time Specification for Java (DRTSJ). The current paper provides a contribution to this latter activity defining, from different angles, a synchronous scheduling service aligned with principles of some popular real-time architectures. This service orchestrates the system in such a way that it provides end-toend guarantees in the distributed transactions, guaranteeing their timely execution across the network and nodes. The service is described from two points of view: the system one, characterizing a portable model; and the programmer one, defining a distributed object-oriented implementation of a model based on Real-Time Remote Method Invocation (RTRMI). Finally, it also presents results of an implementation carried out to judge the efficiency of the service, offering a preliminary predictability and performance assessment of a distributed real-time Java technology.

ACM SIGBED Review, Jan 1, 2005

This paper presents an approach towards a framework that enables the composition of real-time app... more This paper presents an approach towards a framework that enables the composition of real-time applications from existing ubiquitous services. This framework allows to announce services (specifying their QoS requirements in terms of real-time parameters, such as Worst Case Execution Time, WCET), to discover services that perform a certain functionality, and to select the set of those discovered services that will be part of the application to be created. Such service set selection is based on the fulfilment of the QoS requirements of the application. The framework supports static composition, i.e., all services required to create an application have to be discovered before launching the whole application. Finally, it is described the composition model used in the framework.

Proceedings of the …, Jan 1, 2006

Abstract One of the main drawbacks of programming with the RTSJ (The Real-time Specification for ... more Abstract One of the main drawbacks of programming with the RTSJ (The Real-time Specification for Java) is probably its special model of references. The restrictions imposed by the assignment and single parent rules constrains the programming model in such a way that it is sometimes more difficult to use than the Java one. The community has faced this problem producing a special and new set of programming paradigms and patterns, designed to be used in collaboration with the region-based model; this enhances the ...

… Oriented Real-Time …, Jan 1, 2008

Abstract Recently, the application domains where the development of systems with temporal guarant... more Abstract Recently, the application domains where the development of systems with temporal guarantees is needed have increased. The majority of such domains are dynamic environments where the classical design approach is no longer applicable since it is too pessimistic. Thus, new challenges arise to adapt the current methodologies used in different architectural levels to these new environments. New directions and paradigms are needed to allow combining functional flexibility and dynamism with temporal predictability. The ...

ACM SIGBED Review, Jan 1, 2005

The region-based memory model of The Realtime Specification for Java (RTSJ) is quite rigid, and i... more The region-based memory model of The Realtime Specification for Java (RTSJ) is quite rigid, and it complicates the development of reusable predictable software for large-scale systems. In this paper, we propose an extension to the region model of the RTSJ called AGCMemory (Acyclic Garbage Collected Memory). This extension enables the transparent destruction of floating garbage created during the execution of Java methods. The integration within the memory model of the RTSJ and its automatic memory management algorithm, based on run-time barriers, are described.

ACM Transactions on …, Jan 1, 2010

This paper presents an approach to provide real-time support for Java's Remote Method Invocation ... more This paper presents an approach to provide real-time support for Java's Remote Method Invocation (RMI) and its integration with the RTSJ memory model in order to leave out garbage collection. A new construct for remote objects, named No-heap Remote object (NhRo), is introduced. The usage of a NhRo guarantees that memory required to perform a remote invocation (at the server side) does not use heap-memory. Thus, the aim is to avoid garbage collection in the remote invocation process, improving predictability and memory isolation of distributed Java-based real-time applications. The paper presents the bare model and the main programming patterns which are associated with the NhRo model. Sun RMI implementation has been modified to integrate the NhRo model in both static and dynamic environments.

Object Oriented Real- …, Jan 1, 2008

Abstract Current RTSJ (the real-time specification for Java) threading model is dualized: program... more Abstract Current RTSJ (the real-time specification for Java) threading model is dualized: programmers have to decide between the high predictability offered by its region-based model and the flexibility offered by its garbage-collected model. Up to now, there is not a unique type of thread that offers, in a single entity, the highest predictability, and flexibility together. This lack has serious consequences on the programmer who has to deal with new and sometimes non-trivial mechanisms, such as queues of objects or the no-heap real- ...

2010 10th IEEE …, Jan 1, 2010

Abstract Nowadays, there is a trend in industrial systems towards the use of common-off-the-shelf... more Abstract Nowadays, there is a trend in industrial systems towards the use of common-off-the-shelf (COTS) components to develop applications which interact with open systems. This trend includes among others the use of high-level languages, such as Java, and Internet protocols (TCP-IP, HTTP, and Web Services). However, although many industrial systems use these technologies at their business layers, they are far from offering a homogeneous programming platform in their most internal infrastructures. This paper contributes to ...

… for Future Embedded …, Jan 1, 2005

This paper presents an approach towards a framework that enables the composition of real-time app... more This paper presents an approach towards a framework that enables the composition of real-time applications from existing ubiquitous services. This framework allows to announce services (specifying their QoS requirements in terms of real-time parameters, such as Worst Case Execution Time, WCET), to discover services that perform a certain functionality, and to select the set of those discovered services that will be part of the application to be created. Such service set selection is based on the fulfilment of the QoS requirements of the application. The framework supports static composition, i.e., all services required to create an application have to be discovered before launching the whole application.

… Conference on Advanced …, Jan 1, 2009

Abstract Current generation of distributed real-time systems requires more flexibility and the ab... more Abstract Current generation of distributed real-time systems requires more flexibility and the ability of changing its behaviour at run time. This paper presents a model and an algorithm for QoS-aware service composition in distributed systems with real-time requirements. This model is applicable in application domains where temporal guarantees and flexibility are needed, such as remote monitoring, control or surveillance. Our approach combines concepts from the service oriented paradigm and distributed real-time systems. We ...

Concurrency and …, Jan 1, 2011

The proliferation of a new generation of distributed real-time embedded systems (DRE) characteriz... more The proliferation of a new generation of distributed real-time embedded systems (DRE) characterized by special restrictions on its storage capacities, its available computation time, and the messages they can send through the network suggests a comprehensive redesign of the current distribution infrastructure in order to tune its performance. In this changing panorama, the paper concerns one of the protocols, Java's Remote Method Protocol (JRMP), used nowadays to interconnect different nodes of a distributed Java system, and explores the cost of integrating an improved protocol-level multiplexing strategy in the context of an end-to-end remote invocation. The new multiplexing strategy helps middleware manage more efficiently unscheduled invocations that appear at runtime generated from a certain client node, especially in cases where preallocation of resources or dimensioning for the worst-case are techniques not plausible. To this end, the paper examines an alternative based on the definition of a new subprotocol, called ConnectionLess, which offers built-in multiplexing facilities for distributed Java applications. The performance of the new subprotocol is compared against the three already defined by JRMP (namely SingleOp, Stream, and Multiplex), taking into consideration parameters such as memory consumed in the Java's virtual machine and end-to-end response times. JAVA'S REMOTE METHOD PROTOCOL 1241 Figure 4. First remote invocation with each JRMP subprotocol.

New Technologies of …, Jan 1, 2010

Abstract Networked applications structured as a collection of interconnected services offer high ... more Abstract Networked applications structured as a collection of interconnected services offer high flexibility. In this context, services arc functional parts that receive and send messages in a distributed environment. This structure is especially interesting for multimedia/video applications due to their natural mapping to a graph-based structure. In this paper, a component model for the implementation of services is provided. The goal is to obtain services developed with a homogeneous structure to case interoperability. The proposed ...

2009 International Conference on …, Jan 1, 2009

Abstract To support real-time properties, mobile real-time operating system (RTOS) platforms have... more Abstract To support real-time properties, mobile real-time operating system (RTOS) platforms have added to their classical cyclic executive model more flexible concurrency paradigms based on threads and preemptive priority-based scheduling algorithms. However, in newer mobile RTOS, the concurrency model is also going back to prior cooperative multi-tasking models similar to cyclic executives (based on active objects). This paper presents the concurrency model of a very popular mobile RTOS platform, as ...