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47
LIME: A coordination model and middleware supporting mobility of hosts and agents
- ACM Transactions on Software Engineering and Methodology
, 2006
"... Lime (Linda in a Mobile Environment) is a model and middleware supporting the development of applications that exhibit physical mobility of hosts, logical mobility of agents, or both. Lime adopts a coordination perspective inspired by work on the Linda model. The context for computation, represented ..."
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Cited by 75 (11 self)
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Lime (Linda in a Mobile Environment) is a model and middleware supporting the development of applications that exhibit physical mobility of hosts, logical mobility of agents, or both. Lime adopts a coordination perspective inspired by work on the Linda model. The context for computation, represented in Linda by a globally accessible, persistent tuple space, is refined in Lime to transient sharing of identically-named tuple spaces carried by individual mobile units. Tuple spaces are also extended with a notion of location and programs are given the ability to react to specified states. The resulting model provides a minimalist set of abstractions that facilitate rapid and dependable development of mobile applications. In this paper, we illustrate the model underlying Lime, provide a formal semantic characterization for the operations it makes available to the application developer, present its current design and implementation, and discuss lessons learned in developing applications that involve physical mobility.
EgoSpaces: Facilitating Rapid Development of Context-aware Mobile Applications
- IEEE Transactions on Software Engineering, IEEE CS
, 2006
"... Abstract — Today’s mobile applications require constant adaptation to their changing environments, or contexts. Technological advancements have increased the pervasiveness of mobile computing devices such as laptops, handhelds, and embedded sensors. The sheer amount of context information available ..."
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Cited by 63 (5 self)
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Abstract — Today’s mobile applications require constant adaptation to their changing environments, or contexts. Technological advancements have increased the pervasiveness of mobile computing devices such as laptops, handhelds, and embedded sensors. The sheer amount of context information available for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this datarich environment requires a middleware that provides context information to applications in an abstract form. In this paper, we demonstrate the feasibility of such a middleware that allows programmers to focus on high-level interactions among programs and to employ declarative abstract specifications of context in settings that exhibit transient interactions with opportunistically encountered components. We also discuss the novel context-aware abstractions the middleware provides and the programming knowledge necessary to write applications using our middleware. Finally, we provide examples demonstrating the flexibility of the infrastructure and its ability to support differing tasks from a wide variety of application domains. I.
iCAP: interactive prototyping of context-aware applications
- Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics
"... Abstract. Although numerous context-aware applications have been developed and there have been technological advances for acquiring contextual information, it is still difficult to develop and prototype interesting context-aware applications. This is largely due to the lack of programming support av ..."
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Cited by 46 (2 self)
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Abstract. Although numerous context-aware applications have been developed and there have been technological advances for acquiring contextual information, it is still difficult to develop and prototype interesting context-aware applications. This is largely due to the lack of programming support available to both programmers and end-users. This lack of support closes off the contextaware application design space to a larger group of users. We present iCAP, a system that allows end-users to visually design a wide variety of context-aware applications, including those based on if-then rules, temporal and spatial relationships and environment personalization. iCAP allows users to quickly prototype and test their applications without writing any code. We describe the study we conducted to understand end-users mental models of context-aware applications, how this impacted the design of our system and several applications that demonstrate iCAP s richness and ease of use. We also describe a user study performed with 20 end-users, who were able to use iCAP to specify every application that they envisioned, illustrating iCAP s expressiveness and usability. 1
A survey of middleware for sensor networks: state-of-theart and future directions
- Proceedings of the First International Workshop on Middleware for Sensor Networks (MidSens), Melbourne,Australia,28 November
, 2006
"... ABSTRACT In future computing environments, networked sensors will play an increasingly important role in mediating between the physical and virtual worlds. However, programming sensor networks, and the applications that depend on the data they produce, is extremely challenging. The need for suitabl ..."
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Cited by 36 (0 self)
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ABSTRACT In future computing environments, networked sensors will play an increasingly important role in mediating between the physical and virtual worlds. However, programming sensor networks, and the applications that depend on the data they produce, is extremely challenging. The need for suitable middleware to address this problem is evident. In the last few years, various middleware solutions for sensor networks have emerged. These differ in terms of their models for querying and data aggregation, and their assumptions about the topology and other characteristics of the network. Naturally, the assumptions made for each particular middleware limit its potential applicability. Most of the current solutions provide relatively simple query abstractions, and therefore are not suitable for applications that have sophisticated requirements for processing of sensor data in the network. This paper presents a survey and analysis of the current state-of-the art in the field, highlighting the open research challenges. It also draws on the authors' experience with developing middleware for context-aware systems -that is, systems that rely on sensor-derived data to intelligently adapt their behaviour -to propose some future directions for the development of middleware for sensor networks.
Context-Sensitive Resource Discovery
- In Proceedings of the First IEEE International Conference on Pervasive Computing and Communications
, 2003
"... This paper presents the "Solar" system framework that allows resources to advertise context-sensitive names and for applications to make context-sensitive name queries. The heart of our framework is a small specification language that allows composition of "context-processing operator ..."
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Cited by 35 (5 self)
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This paper presents the "Solar" system framework that allows resources to advertise context-sensitive names and for applications to make context-sensitive name queries. The heart of our framework is a small specification language that allows composition of "context-processing operators" to calculate the desired context. Resources use the framework to register names, and applications use the framework to look up contextsensitive name descriptions. The back-end system executes these operators and constantly updates the context values, adjusting advertised names and informing applications about changes. We report experimental results from a prototype, using a modified version of the Intentional Naming System (INS) as the core directory service.
V.: Efficient context-aware service discovery in multi-protocol pervasive environments
- In: Proc. of MDM (2006
"... Service discovery is a critical functionality of emerging pervasive computing environments. In such environments, service discovery mechanisms need to (i) overcome the heterogeneity of hardware devices, software platforms, and networking infrastructures; and (ii) provide users with an accurate selec ..."
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Cited by 23 (8 self)
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Service discovery is a critical functionality of emerging pervasive computing environments. In such environments, service discovery mechanisms need to (i) overcome the heterogeneity of hardware devices, software platforms, and networking infrastructures; and (ii) provide users with an accurate selection of services that meet their current requirements. To address these issues, we have developed the Multi-Protocol Service Discovery and Access (MSDA) middleware platform 2, which provides context-aware service discovery and access in pervasive environments. This paper primarily focuses on the design and implementation of the context-awareness support of MSDA. Context-awareness not only provides a more accurate service selection, but also enables a more efficient dissemination of service requests across heterogeneous pervasive environments. We present the design and prototype implementation of MSDA, along with experimental results that demonstrate the advantages derived by introducing context awareness. 1.
Opportunistic Channels: Mobility-aware Event Delivery
- In Proceedings of the ACM/USENIX International Middleware Conference
, 2003
"... The delivery of data in pervasive systems has to deal with end host mobility. One problem is how to create appropriate, applicationlevel data provisioning topologies, termed data brokers, to best match underlying network connectivity, end user locations, and the locales of their network access. ..."
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Cited by 14 (8 self)
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The delivery of data in pervasive systems has to deal with end host mobility. One problem is how to create appropriate, applicationlevel data provisioning topologies, termed data brokers, to best match underlying network connectivity, end user locations, and the locales of their network access. Another problem is how to balance workloads in such overlay networks, in response to mobility and to changes in available processing and communication resources. This paper improves the performance of data provisioning by dynamically changing broker topologies and end users' assignments to brokers. Specifically, using publish /subscribe as a communication paradigm, a new abstraction, termed an opportunistic event channel, enables dynamic broker creation, deletion, and movement. Experimental and simulation results demonstrate the ability of opportunistic channels to optimize event delivery and processing when end users move across di#erent network access points. The technique is to `opportunistically' follow network-level hando#s across network access points with application-level hando#s of a user's broker functionality to a new, `closer' broker. The potential load imbalances across brokers caused by such hando#s are also addressed.
MoCoA: Customisable Middleware for Context-Aware Mobile Applications
- In Proc. 8th International Symposium on Distributed Objects and Applications
, 2006
"... Abstract. Many programming models have been proposed to facilitate the development of context-aware applications. However, previous work does not offer support for building customised systems and has largely been targeted at a single application domain. In this paper, we describe MoCoA, a flexible m ..."
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Cited by 11 (4 self)
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Abstract. Many programming models have been proposed to facilitate the development of context-aware applications. However, previous work does not offer support for building customised systems and has largely been targeted at a single application domain. In this paper, we describe MoCoA, a flexible middleware framework that permits the rapid development of context-aware applications and supports deployment scenarios ranging from augmented artefacts to city-wide smart-space applications. Crucially, MoCoA supports a small set of programming abstractions that are suitable for building a wide range of context-aware applications for deployment in a fixed or (ad hoc) mobile environment. For each of these abstractions, MoCoA provides a set of implementations via a library of components. We present three applications of the MoCoA framework that demonstrate both the use of the programming abstractions and the flexibility of the framework. 1
Content-based Publish-Subscribe in a Mobile Environment
"... Content-based publish-subscribe is emerging as a communication paradigm able to cope with the needs of scalability, flexibility, and reconfigurability typical of highly dynamic distributed applications. However, very few efforts address dynamic changes in the topology of the publish-subscribe di ..."
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Cited by 10 (5 self)
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Content-based publish-subscribe is emerging as a communication paradigm able to cope with the needs of scalability, flexibility, and reconfigurability typical of highly dynamic distributed applications. However, very few efforts address dynamic changes in the topology of the publish-subscribe distributed dispatching infrastructure---a fundamental challenge in mobile computing scenarios. In this chapter we illustrate the problems posed by mobility in the context of publish-subscribe, discuss protocols and integrated solutions proposed by our research group, and survey the state of the art in this research area.
S.: Granular context in collaborative mobile environments
- OTM 2006 Workshops. LNCS
, 2006
"... Abstract. Our research targets collaborative environments with focus on mobility and teams. Teams comprise a number of people working on multiple projects and activities simultaneously. As mobile and wireless technology advances people are no longer bound to their offices. Team members are able to c ..."
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Cited by 9 (6 self)
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Abstract. Our research targets collaborative environments with focus on mobility and teams. Teams comprise a number of people working on multiple projects and activities simultaneously. As mobile and wireless technology advances people are no longer bound to their offices. Team members are able to collaborate while on the move. Sharing context information thus becomes a vital part of collaborative environments. However, challenges such as heterogeneous devices, connectivity, and bandwidth arise due to the dynamic nature of distributed, mobile teams. We present a methodology for context modeling and employ a framework that reduces costs such as computing information and usage of network resources by transferring context at relevant levels of detail. At the same time, robustness of the system is improved by dealing with uncertain context information. Our framework is implemented on an OSGi container platform using Web services for communication means. 1
