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Scaling Spatial Alarm Services on Road Networks
"... Abstract—Spatial alarm services are essential components of many location-based applications. One of the key technical chal-lenges for supporting spatial alarms as a service is performance and scalability. This paper shows that the Euclidean distance-based spatial alarm processing techniques are ina ..."
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Abstract—Spatial alarm services are essential components of many location-based applications. One of the key technical chal-lenges for supporting spatial alarms as a service is performance and scalability. This paper shows that the Euclidean distance-based spatial alarm processing techniques are inadequate for mobile users traveling on road networks due to the high overhead in terms of server load for alarm checks and the high energy consumption in terms of client wakeups. We design and develop ROADALARM, a road network aware spatial alarm processing ser-vice, with three unique features. First, we introduce the concept of road network-based spatial alarms using road network distance measures and a set of metrics specialized for spatial alarm processing. Second, we develop the basic model for spatial alarm processing by exploiting two types of filters: subscription filter and Euclidean lower bound filter. Third and but not the least, we develop a suite of optimization techniques to further reduce the frequency of wakeups at mobile clients and the number of alarm checks at the alarm processing server, while ensuring high accuracy of spatial alarm processing. Our experimental results show that ROADALARM outperforms existing Euclidean space-based approaches with high success rate (accuracy) and significantly increased hibernation time. I.
Information Technology and Computer Science
"... Abstract-Within the last decade, the continuous development of mobile technology has motivated an intense research in mobile data services. Among these services, location-based services and location-dependant queries have attracted a lot of attention from the software industry as well as from resea ..."
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Abstract-Within the last decade, the continuous development of mobile technology has motivated an intense research in mobile data services. Among these services, location-based services and location-dependant queries have attracted a lot of attention from the software industry as well as from researchers. Although a number of locations based service methods have been proposed, the performance is not satisfactory in the case of dynamic data management problems that introduce high overhead in update and query operations. In this paper, we introduce a proxy based distributed dynamic data management architecture for location based services that reduces network cost with required quality of service (QoS). The system proposes a distributed hierarchical database structure with collocated proxy for efficient service delivery to location-dependant queries especially Range Queries (RQ). The system that we propose have the following advantages. i) It performs efficient processing of location dependant queries, especially Range Queries spanning over multiple network cells ii) It reduces wireless communication between mobile devices and servers. iii) The system is scalable where location data is distributed and arranged hierarchically. We use proxy objects to carry out processing task for each mobile user. Thus proxies play an important role and in charge of routing the queries to different (distributed) databases and present the results to queries efficiently. Simulation study shows the effectiveness of our proposed architecture.
A Motion-Aware Safe Period-based Framework for Spatial Alarm Processing
"... Spatial alarms are set on a spatial location of interest which the subscribers of the alarm will travel to sometime in the future. Alarm processing requires meeting two demanding objectives: high accuracy, which ensures zero or very low alarm misses, and high scalability, which requires highly effic ..."
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Spatial alarms are set on a spatial location of interest which the subscribers of the alarm will travel to sometime in the future. Alarm processing requires meeting two demanding objectives: high accuracy, which ensures zero or very low alarm misses, and high scalability, which requires highly efficient and optimal processing of spatial alarms. In this paper, we propose to use safe period optimizations to minimize the number of unnecessary spatial alarm evaluations, increasing the throughput and scalability of the system. We also develop a suite of alarm grouping techniques, based on spatial locality of the alarms and motion behavior of the mobile users, which reduce the safe period computation costs. Subscriber mobility-based optimizations are introduced to further enhance the performance of the system. An evaluation of our approach using a road network simulator shows that the proposed motion-aware safe period-based approach to spatial alarm processing offers significant performance enhancements. 1
mTrigger: An Event-based Framework for Location-based Mobile Triggers ABSTRACT
"... Location-based triggers are the fundamental capability for supporting location-based advertisements, location-based entertainment applications, personal reminders, as well as presence-based information sharing applications. In this chapter, we describe the design and the implementation of mTrigger, ..."
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Location-based triggers are the fundamental capability for supporting location-based advertisements, location-based entertainment applications, personal reminders, as well as presence-based information sharing applications. In this chapter, we describe the design and the implementation of mTrigger, an event-based framework for scalable processing of location-based mobile triggers (location triggers for short). A location trigger is a standing spatial trigger specified with the spatial region over which the trigger is set, the actions to be taken when the trigger conditions are met, and the list of recipients to whom the notification will be sent upon the firing of the location trigger. The mTrigger framework consists of three alternative architectures for supporting location triggers: (1) the client-server architecture, which allows mobile clients to register and install location triggers of interest on the mTrigger server system; the server being responsible for processing location triggers, performing associated actions and sending out notifications upon firing of triggers; (2) the client-centric architecture, which enables mobile users to manage and process location triggers on their own mobile clients; and (3) the decentralized peer-to-peer architecture, which allows mobile users to collaborate with one another in terms of location trigger
IEEE TRANSACTIONS ON MOBILE COMPUTING 1 Road Network-Aware Spatial Alarms
"... Abstract—Road network-aware spatial alarms extend the concept of time-based alarms to spatial dimension and remind us when we travel on spatially constrained road networks and enter some predefined locations of interest in the future. This paper argues that road network-aware spatial alarms need to ..."
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Abstract—Road network-aware spatial alarms extend the concept of time-based alarms to spatial dimension and remind us when we travel on spatially constrained road networks and enter some predefined locations of interest in the future. This paper argues that road network-aware spatial alarms need to be processed by taking into account spatial constraints on road networks and mobility patterns of mobile subscribers. We show that the Euclidian distance-based spatial alarm processing techniques tend to incur high client energy consumption due to unnecessarily frequent client wakeups. We design and develop a road network-aware spatial alarm processing system, called ROADALARM, with three unique features. First, we introduce the concept of road network-based spatial alarms using road network distance measures. Instead of using a rectangular region, a road network-aware spatial alarm is a star-like subgraph with an alarm target as the center of the star and border points as the scope of the alarm region. Second, we describe a baseline approach for spatial alarm processing by exploiting two types of filters. We use subscription filter and Euclidean lower bound filter to reduce the amount of shortest path computations required in both computing alarm hibernation time and performing alarm checks at the server. Last but not the least, we develop a suite of optimization techniques using motion-aware filters, which enable us to further increase the hibernation time of mobile clients and reduce the frequency of wakeups and alarm checks, while ensuring high accuracy of spatial alarm processing. Our experimental results show that the road network-aware spatial alarm processing significantly outperforms existing Euclidean space-based approaches, in terms of both the number of wakeups and the hibernation time at mobile clients and the number of alarm checks at the server. Index Terms—Spatial alarms, road networks, motion behavior, optimization, scalability. F 1