Extensions to the actor model have been proposed to ease the development of mobile ad hoc applications. However, programming in the actor model is still difficult as it does not provide abstractions to synchronously coordinate multiple actors. Thus, when programmers want to coordinate two or more actors they have to do it by hand. Additionally, programmers need to write failure recovery code for failures caused by the concurrent access to the actors they are using. Coding this manually is error prone and might even be not feasible. We propose a language abstraction based on software transactional memory to coordinate actors. We show that the integration of software transactional memory with the actor model makes writing failure recovery code superfluous. Moreover, we show that our system even handles those cases where manually writing the failure recovery code is not feasible.
{"title":"Ambient transactors","authors":"Christophe Scholliers, T. V. Cutsem, W. Meuter","doi":"10.1145/1462789.1462798","DOIUrl":"https://doi.org/10.1145/1462789.1462798","url":null,"abstract":"Extensions to the actor model have been proposed to ease the development of mobile ad hoc applications. However, programming in the actor model is still difficult as it does not provide abstractions to synchronously coordinate multiple actors. Thus, when programmers want to coordinate two or more actors they have to do it by hand. Additionally, programmers need to write failure recovery code for failures caused by the concurrent access to the actors they are using. Coding this manually is error prone and might even be not feasible. We propose a language abstraction based on software transactional memory to coordinate actors. We show that the integration of software transactional memory with the actor model makes writing failure recovery code superfluous. Moreover, we show that our system even handles those cases where manually writing the failure recovery code is not feasible.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115603466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In ubiquitous computing systems, heterogeneous applications must be capable of responding to dynamic changes in their environments with minimal human interference and strongly relying on context information. Reasoning is necessary in ubiquitous systems mainly for transforming raw context data into meaningful information and for infering new implicit context information that may be relevant for the applications. Besides that, reasoning is fundamental for triggering actions or adaptations according to specific situations described by rules. These rules typically depend on several context variables, which may originate from different distributed sources. Hence, we propose a strategy for cooperative context reasoning of complex situations involving a reasoner for the user side and a reasoner for the ambient side.
{"title":"A strategy for cooperative reasoning in ubiquitous computing environments","authors":"J. V. Filho, M. Endler","doi":"10.1145/1462789.1462801","DOIUrl":"https://doi.org/10.1145/1462789.1462801","url":null,"abstract":"In ubiquitous computing systems, heterogeneous applications must be capable of responding to dynamic changes in their environments with minimal human interference and strongly relying on context information. Reasoning is necessary in ubiquitous systems mainly for transforming raw context data into meaningful information and for infering new implicit context information that may be relevant for the applications. Besides that, reasoning is fundamental for triggering actions or adaptations according to specific situations described by rules. These rules typically depend on several context variables, which may originate from different distributed sources. Hence, we propose a strategy for cooperative context reasoning of complex situations involving a reasoner for the user side and a reasoner for the ambient side.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125502377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This position paper discusses the challenges and trade-offs of implementing a middleware that supports ubiquitous contextawareness, i.e., a scenario where context-aware applications may move throught network environments without suffering disruptions in their context-based interactions. We present a middleware approach based on the concept of context domains that satisfy some of the requirements of this scenario.
{"title":"Middleware for ubiquitous context-awareness","authors":"R. Rocha, M. Endler, Thiago Senador de Siqueira","doi":"10.1145/1462789.1462797","DOIUrl":"https://doi.org/10.1145/1462789.1462797","url":null,"abstract":"This position paper discusses the challenges and trade-offs of implementing a middleware that supports ubiquitous contextawareness, i.e., a scenario where context-aware applications may move throught network environments without suffering disruptions in their context-based interactions. We present a middleware approach based on the concept of context domains that satisfy some of the requirements of this scenario.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121060968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eskindir Asmare, A. Gopalan, M. Sloman, Naranker Dulay, Emil C. Lupu
Unmanned Autonomous Vehicles (UAVs) are increasingly deployed for missions that are deemed dangerous or impractical to perform by humans in many military and disaster scenarios. Collaborating UAVs in a team form a Self-Managed Cell (SMC) with at least one commander. UAVs in an SMC may need to operate independently or in sub-groups, out of contact with the commander and the rest of the team in order to perform specific tasks, but must still be able to eventually synchronise state information. The SMC must also cope with intermittent and permanent communication failures as well permanent UAV failures. This paper describes a failure management scheme that copes with both communication link and UAV failures, which may result in temporary disjoint sub-networks within the SMC. A communication management protocol is proposed to control UAVs performing disconnected individual operations, while maintaining the SMC's structure by trying to ensure that all members of the mission regardless of destination or task, can communicate by moving UAVs to act as relays or by allowing the UAVs to rendezvous at intermittent intervals.
{"title":"Adaptive self-management of teams of autonomous vehicles","authors":"Eskindir Asmare, A. Gopalan, M. Sloman, Naranker Dulay, Emil C. Lupu","doi":"10.1145/1462789.1462790","DOIUrl":"https://doi.org/10.1145/1462789.1462790","url":null,"abstract":"Unmanned Autonomous Vehicles (UAVs) are increasingly deployed for missions that are deemed dangerous or impractical to perform by humans in many military and disaster scenarios. Collaborating UAVs in a team form a Self-Managed Cell (SMC) with at least one commander. UAVs in an SMC may need to operate independently or in sub-groups, out of contact with the commander and the rest of the team in order to perform specific tasks, but must still be able to eventually synchronise state information. The SMC must also cope with intermittent and permanent communication failures as well permanent UAV failures. This paper describes a failure management scheme that copes with both communication link and UAV failures, which may result in temporary disjoint sub-networks within the SMC. A communication management protocol is proposed to control UAVs performing disconnected individual operations, while maintaining the SMC's structure by trying to ensure that all members of the mission regardless of destination or task, can communicate by moving UAVs to act as relays or by allowing the UAVs to rendezvous at intermittent intervals.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117269276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pervasive computing in mobile ad hoc networks requires that applications query their network environment for services and react to a plethora of events fired by other devices in that network responding to such queries. Current context-aware and event-driven architectures require the programmer to react to these events via a carefully crafted network of observers and event handlers, while inherently introducing complex concurrency issues. This paper proposes the integration of two techniques to solve these problems: ambient references and reactive programming. Ambient references are object-oriented communication abstractions that represent nearby remote objects in the mobile network and that make it possible to generate the events mentioned above. The reactive programming paradigm provides an abstraction over events such that the application can be written in a conventional programming style with explicit control flow.
{"title":"Reactive queries in mobile ad hoc networks","authors":"A. Carreton, T. V. Cutsem, W. Meuter","doi":"10.1145/1462789.1462792","DOIUrl":"https://doi.org/10.1145/1462789.1462792","url":null,"abstract":"Pervasive computing in mobile ad hoc networks requires that applications query their network environment for services and react to a plethora of events fired by other devices in that network responding to such queries. Current context-aware and event-driven architectures require the programmer to react to these events via a carefully crafted network of observers and event handlers, while inherently introducing complex concurrency issues. This paper proposes the integration of two techniques to solve these problems: ambient references and reactive programming. Ambient references are object-oriented communication abstractions that represent nearby remote objects in the mobile network and that make it possible to generate the events mentioned above. The reactive programming paradigm provides an abstraction over events such that the application can be written in a conventional programming style with explicit control flow.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122473391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many GIS (Geographic Information Systems) based routing applications use single-dimensional spatial-aware algorithms such as shortest route, or fastest route. However, ideally, we often want to route goods or people based upon a multiple dimensional or multi-valued goal such as some compromise between a short route, a fast route and a more scenic route. This makes location deviations of mobile user routing more complex to handle because of the interplay between multiple value objectives or goals. In this paper, a reflective context-aware model is proposed, built upon a multi-valued objective routing algorithm which is able to adapt to dynamic environment changes in a more flexible and robust way.
{"title":"A reflective context-aware system for spatial routing applications","authors":"Dejian Meng, S. Poslad","doi":"10.1145/1462789.1462799","DOIUrl":"https://doi.org/10.1145/1462789.1462799","url":null,"abstract":"Many GIS (Geographic Information Systems) based routing applications use single-dimensional spatial-aware algorithms such as shortest route, or fastest route. However, ideally, we often want to route goods or people based upon a multiple dimensional or multi-valued goal such as some compromise between a short route, a fast route and a more scenic route. This makes location deviations of mobile user routing more complex to handle because of the interplay between multiple value objectives or goals. In this paper, a reflective context-aware model is proposed, built upon a multi-valued objective routing algorithm which is able to adapt to dynamic environment changes in a more flexible and robust way.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123733059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Today, the work of disaster response teams is being increasingly supported and coordinated by using portable computing devices. Connected to mobile ad-hoc networks, these devices establish a communication infrastructure immune to damages caused by natural disasters. However, ad-hoc networks are dynamic and volatile environments, which hampers hosting of critical applications relying on fast responsiveness. These difficulties can be mitigated to some extent at the middleware level. In this paper we present RESCUE, an open-source middleware for service-oriented communication in mobile disaster response environments. RESCUE has been designed to address challenges of dynamic ad-hoc networks for service discovery and invocation and provides an infrastructure for flexible mobile systems based on loosely coupled services.
{"title":"A middleware for service-oriented communication in mobile disaster response environments","authors":"Lukasz Juszczyk, S. Dustdar","doi":"10.1145/1462789.1462796","DOIUrl":"https://doi.org/10.1145/1462789.1462796","url":null,"abstract":"Today, the work of disaster response teams is being increasingly supported and coordinated by using portable computing devices. Connected to mobile ad-hoc networks, these devices establish a communication infrastructure immune to damages caused by natural disasters. However, ad-hoc networks are dynamic and volatile environments, which hampers hosting of critical applications relying on fast responsiveness. These difficulties can be mitigated to some extent at the middleware level. In this paper we present RESCUE, an open-source middleware for service-oriented communication in mobile disaster response environments. RESCUE has been designed to address challenges of dynamic ad-hoc networks for service discovery and invocation and provides an infrastructure for flexible mobile systems based on loosely coupled services.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116541300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we present a new method to realize a selforganizing and self-stabilizing publish/subscribe middleware for wireless actuator and sensor networks. By using simple, yet powerful compositional rules, our approach forms hierarchical clusters of nodes and sets up many small publish/subscribe networks, that interact with each other. Thereby, we are able to integrate the necessary routing of messages between clusters into the publish/subscribe substrate itself. This technique reveals several benefits, such as redundant routes and automatic route recovery, which show up as emergent behavior at no additional cost. The provided publish/subscribe middleware allows an elegant design of eventbased applications for pervasive environments.
{"title":"Clustered publish/subscribe in wireless actuator and sensor networks","authors":"J. Schönherr, Helge Parzyjegla, Gero Mühl","doi":"10.1145/1462789.1462800","DOIUrl":"https://doi.org/10.1145/1462789.1462800","url":null,"abstract":"In this paper, we present a new method to realize a selforganizing and self-stabilizing publish/subscribe middleware for wireless actuator and sensor networks. By using simple, yet powerful compositional rules, our approach forms hierarchical clusters of nodes and sets up many small publish/subscribe networks, that interact with each other. Thereby, we are able to integrate the necessary routing of messages between clusters into the publish/subscribe substrate itself. This technique reveals several benefits, such as redundant routes and automatic route recovery, which show up as emergent behavior at no additional cost. The provided publish/subscribe middleware allows an elegant design of eventbased applications for pervasive environments.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126034645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Frederico Lopes, Flávia Coimbra Delicato, T. Batista, N. Cacho
The use of context provision middleware is a promising approach for dealing with the low-level functions involved in handling contextual events when building ubiquitous applications. Several middleware platforms are currently available that provide support for context handling, each one adopting different models for interacting with applications and representing contextual data, and aiming at handling different types of context. There are ubiquitous applications that need dealing with a high degree of heterogeneous context sources and detection of complex event patterns thus requiring support of different and often noninteroperable middleware platforms. For this kind of application, developers must handle the platform heterogeneity, thus increasing the complexity of the application code. To address this issue, we propose OpenCOPI (Open COntext Platform Integration), a context platform that integrates several context provision middleware and provides common services for handling the composition of contextual events in order to offer a unified context platform. This paper introduces OpenCOPI and details its composition event service, CES, showing the integrating of two context middleware. The paper also describes a case study, based on a Meeting Detection System, to illustrate the use of CES.
{"title":"On the integration of context-based heterogeneous middleware for ubiquitous computing","authors":"Frederico Lopes, Flávia Coimbra Delicato, T. Batista, N. Cacho","doi":"10.1145/1462789.1462795","DOIUrl":"https://doi.org/10.1145/1462789.1462795","url":null,"abstract":"The use of context provision middleware is a promising approach for dealing with the low-level functions involved in handling contextual events when building ubiquitous applications. Several middleware platforms are currently available that provide support for context handling, each one adopting different models for interacting with applications and representing contextual data, and aiming at handling different types of context. There are ubiquitous applications that need dealing with a high degree of heterogeneous context sources and detection of complex event patterns thus requiring support of different and often noninteroperable middleware platforms. For this kind of application, developers must handle the platform heterogeneity, thus increasing the complexity of the application code. To address this issue, we propose OpenCOPI (Open COntext Platform Integration), a context platform that integrates several context provision middleware and provides common services for handling the composition of contextual events in order to offer a unified context platform. This paper introduces OpenCOPI and details its composition event service, CES, showing the integrating of two context middleware. The paper also describes a case study, based on a Meeting Detection System, to illustrate the use of CES.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122463613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We advocate using deontic logic and its representation in the Event Calculus to control access to information in a distributed ubiquitous system. Contracts between information owners are encoded in terms of classes of organisations, data, and interactions. Fluents, events, and application-specific rules that link the two are then extracted from the contracts and mapped to the components, endpoints, and messages used to implement the system. The expression of organisations' responsibilities is natural and leads to a simple mechanism of data flow monitoring. Some parts of the system can make forward progress while others are in conflict, meaning that resolution does not impede other processing. Furthermore, specification in terms of entities' behaviour rather than explicit modelling of service level agreements (SLAs) means that it is straightforward to make decisions based on observations that are not specified in the SLA but that are noticed by a human as being abnormal.
{"title":"Deontic logic for modelling data flow and use compliance","authors":"David Evans, D. Eyers","doi":"10.1145/1462789.1462793","DOIUrl":"https://doi.org/10.1145/1462789.1462793","url":null,"abstract":"We advocate using deontic logic and its representation in the Event Calculus to control access to information in a distributed ubiquitous system. Contracts between information owners are encoded in terms of classes of organisations, data, and interactions. Fluents, events, and application-specific rules that link the two are then extracted from the contracts and mapped to the components, endpoints, and messages used to implement the system. The expression of organisations' responsibilities is natural and leads to a simple mechanism of data flow monitoring. Some parts of the system can make forward progress while others are in conflict, meaning that resolution does not impede other processing. Furthermore, specification in terms of entities' behaviour rather than explicit modelling of service level agreements (SLAs) means that it is straightforward to make decisions based on observations that are not specified in the SLA but that are noticed by a human as being abnormal.","PeriodicalId":364168,"journal":{"name":"workshop on Middleware for Pervasive and Ad-hoc Computing","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122229676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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