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Mobile and Ubiquitous Systems: Networking & Services, MobiQuitous, 2009. MobiQuitous '09. 6th Annual International

Date 13-16 July 2009

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Displaying Results 1 - 25 of 72
  • [Title page]

    Publication Year: 2009 , Page(s): 1
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  • Steering Committee

    Publication Year: 2009 , Page(s): 1 - 3
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  • Welcome message from general chair

    Publication Year: 2009 , Page(s): 1 - 2
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  • Message from the Program Chairs

    Publication Year: 2009 , Page(s): 1
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  • Message from the SensorFusion'09 program chairs

    Publication Year: 2009 , Page(s): 1
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  • Mobile healthcare workshop message

    Publication Year: 2009 , Page(s): 1 - 2
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  • Health untethered

    Publication Year: 2009 , Page(s): 1 - 2
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  • Design principles for robust opportunistic communication

    Publication Year: 2009 , Page(s): 1 - 2
    Cited by:  Papers (1)
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  • Table of contents

    Publication Year: 2009 , Page(s): 1 - 4
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  • MobiQuitous 2009

    Publication Year: 2009 , Page(s): 1
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  • Social context: Supporting interaction awareness in ubiquitous environments

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (12365 KB) |  | HTML iconHTML  

    In ubiquitous computing environments, certain entities (or actors) often need to interact with each other in achieving a joint goal in a dynamically changing context. To perform such interactions in a seamless manner, the actors need to be aware of not only their physical context (e.g. location) but also their changing relationships with respect to the particular task or goal. The latter interaction-oriented context, which we refer to as social context, has significant impacts on the way actors manage their adaptive behavior. However, very little research has focused on supporting such social context in ubiquitous environments. This paper presents our novel approach to modeling and realizing social context. Social context is modeled as a managed composition of loosely-coupled roles with their interaction relationships expressed as contracts. In addition, it is modeled from an individual actor's perspective to allow for possible differences in the actors' perception of the relationships. The social contexts of an actor are externalized from the actor itself to achieve easy management of the actors' adaptive behavior concerning interaction. A layered system architecture is introduced to realize the approach and demonstrate the development of automotive telematics systems that are physically and socially context-aware. View full abstract»

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  • Multi-layered friendship modeling for location-based Mobile Social Networks

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (8733 KB) |  | HTML iconHTML  

    Location-based Mobile Social Networks (MSNs) are becoming increasingly popular given the success of Online Social Networks (OSNs), such as Facebook and MySpace, and recent availability of open mobile platforms, such as Apple iPhones and Google Android phones. MSNs extend existing OSNs by allowing a user to know when her friends are around and by providing the ability to meet new people who share her interests. There are few studies, however, on how users are connected through these emerging location-based MSNs. In this paper, we present analysis results of a commercial MSN for which we quantified the correlation between users' friendship with their mobility characteristics, social graph properties, and user profiles. The evaluation of the derived model from the empirical traces suggests that the model-based friend recommendation is effective, and its performance is better than well-known Naive Bayes classifier and J48 decision tree algorithms. To the best of our knowledge, this paper presents the first study that models the friendship connections over a real-world location-based MSN. View full abstract»

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  • “I can't lie anymore!”: The implications of location automation for mobile social applications

    Publication Year: 2009 , Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2945 KB) |  | HTML iconHTML  

    Human factors research has shown that automation is a mixed blessing. It changes the role of the human in the loop with effects on understanding, errors, control, skill, vigilance, and ultimately trust and usefulness. We raise the issue that many current mobile applications involve mechanisms that surreptitiously collect and propagate location information among users and we provide results from the first systematic real world study of the matter. Our observations come from a case study of Jaiku, a mobile microblogging service that automates disclosure and diffusion of location information. Three user groups in Finland and California used Jaiku for several months. The results reveal issues related to control, understanding, emergent practices, and privacy. The results convey that unsuitable automated features can preclude use in a group. While one group found automated features useful, and another was indifferent toward it, the third group stopped using the application almost entirely. To conclude, we discuss the need for user-centered development of automated features in location-based services. View full abstract»

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  • Security for pervasive medical sensor networks

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (4727 KB) |  | HTML iconHTML  

    Wireless sensor networks are going to allow for ubiquitous health monitoring, improving users' well-being, the healthcare system, and helping to quickly react on emergency situations. Meeting the strict security needs of these ubiquitous medical applications is a big challenge, since safety and privacy of medical data has to be guaranteed all the way from the sensor nodes to the back-end services, the system has to fulfill latency needs, and lots of mobility is expected. In this paper, we introduce a deployment model for wireless sensor networks for pervasive healthcare based on the concepts of patient area networks and medical sensor networks, and propose a complete and efficient security framework for them. Our security framework is organized into three layers, addressing the operational requirements and security needs at the patient area network, medical sensor network and back-end levels. We specify how these layers are interconnected with each other as well as the needed security mechanisms that allow for the efficient and practical deployment of secure pervasive healthcare systems based on wireless sensor networks. View full abstract»

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  • EagleVision: A pervasive mobile device protection system

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (1)  |  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (7249 KB) |  | HTML iconHTML  

    Mobile devices like laptops, iPhones and PDAs are highly susceptible to theft in public places like airport terminal, library and cafe. Moreover, the exposure of sensitive data stored in the mobile device could be more damaging than the loss of device itself. In this work, we propose and implement a pervasive mobile device protection system, named EagleVision, based on sensing and wireless networking technologies. Comparing with existing solutions, EagleVision is unique in providing an integrated protection to both device and data. It is a context-aware system which adjusts the protection level to the mobile device dynamically according to the context information such as the user proximity to the mobile device, which is collected via the interactions between the sensors carried by the user, embedded with the mobile device and deployed in the surrounding environment. Furthermore, it does not require explicit user intervention to utilize the system and hence avoid adding extra distractions to the user. Prototype implementation and extensive field test results demonstrate the effectiveness of EagleVision. View full abstract»

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  • Hash-Based Sequential Aggregate and Forward Secure Signature for Unattended Wireless Sensor Networks

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (7140 KB) |  | HTML iconHTML  

    Unattended Wireless Sensor Networks (UWSNs) operating in hostile environments face great security and performance challenges due to the lack of continuous real-time communication between senders (sensors) and receivers (e.g., mobile data collectors, static sinks). The lack of real-time communication forces sensors to accumulate the sensed data possibly for long time periods, along with the corresponding signatures for authentication purposes. Moreover, non-real-time characteristic of UWSNs makes sensors vulnerable especially to active adversaries, which compromise sensors and extract all data stored in them. Hence, it is critical to have forward security property such that even if the adversary can compromise the current keying materials, she cannot modify or forge authenticated data generated before the node compromise. Forward secure and aggregate signatures are cryptographic primitives developed to address these issues. Unfortunately, existing forward secure and aggregate signature schemes either impose substantial computation and storage overhead, or do not allow public verifiability, thereby impractical for resource-constrained UWSNs. In order to address these problems, we propose a new class of signature schemes, which we refer to as Hash-Based Sequential Aggregate and Forward Secure Signature (HaSAFSS). Such a scheme allows a signer to sequentially generate a compact, fixed-size, and publicly verifiable signature at a nearly optimal computational cost. We propose two HaSAFSS schemes, symmetric HaSAFSS (Sym-HaSAFSS) and Elliptic Curve Cryptography (ECC) based HaSAFSS (ECC-HaSAFSS). Both schemes integrate the efficiency of MAC-based aggregate signatures and the public verifiability of bilinear map based signatures by preserving forward security via Timed-Release Encryption (TRE). We demonstrate that our schemes are secure under appropriate computational assumptions. We also show that our schemes are significantly more efficient in terms of both computational an- d storage overheads than previous schemes, and therefore quite practical for even highly resource-constrained UWSN applications. View full abstract»

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  • Implementation and evaluation of a mobile tetherless VoIP/PSTN gateway

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (8034 KB) |  | HTML iconHTML  

    A voice-over-IP (VoIP) gateway bridges IP-based packet-switched networks (i.e. Internet) with public circuit-switched telephone networks (i.e. PSTN). The key building block of a VoIP gateway is a telephony card that interfaces with the PSTN and converts signals from the PSTN to bits that can be manipulated by a computer and vice versa. Because commercially available telephony cards only work with wired PSTN lines, almost all existing VoIP gateways are tethered and therefore do not support the kind of mobility enabled by modern wireless communications technology. This paper describes the implementation and evaluation of a mobile VoIP gateway called WGate that is designed specifically to bridge wireless VoIP clients and cellular phones, and can thus be easily deployed on demand in particular geographical locations. The key innovation of WGate is the ability to use a Bluetooth link as a wireless backplane by exploiting the Hands-Free profile of the Bluetooth protocol stack and eventually turning a set of commodity bluetooth-capable cell phones into a multi-port telephony card. Empirical measurements on a working prototype show that this approach can scale a VoIP gateway up to 8 cell phones because state-of-the-art Bluetooth adapters can only support up to 8 simultaneous Synchronous Connection-Oriented (SCO) connections when they operate in physically close proximity. View full abstract»

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  • Model-based fault Diagnosis for IEEE 802.11 wireless LANs

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (10323 KB) |  | HTML iconHTML  

    The increasingly deployed IEEE 802.11 wireless LANs (WLANs) challenge traditional network management systems because of the shared open medium and the varying channel conditions. There needs to be an automated tool that can help diagnosing both malicious security faults and benign performance faults. It is often difficult, however, to identify the root causes since the manifesting anomalies from network measurements are highly interrelated. In this paper we present a novel approach, called MOdel-based self-Diagnosis (MODI), for fault detection and localization. Our solution consists of Structural and Behavioral Model (SBM) that is constructed using both structural causality from wireless protocol specifications and behavioral statistics from network measurements. We use logic-based backward reasoning to automate fault detection and localization based on SBM, by comparing observed network measurements with expected network behaviors and by tracing back causality structures. The reasoning algorithm and the model description are decoupled so a SBM model can be easily updated for varying WLAN configurations and changing network conditions. Compared to previous work, the contribution of this paper is the architecture and the algorithm of the diagnosis core, rather than the WLAN measurement techniques. We built and deployed MODI-embedded wireless APs that can detect both security attacks and troubleshoot performance problems. These MODI-enabled APs can also cooperate to diagnose cross-AP problems, such as those caused by device mobility. The evaluation results demonstrate that the proposed model-based diagnosis is fast and effective with little overhead. View full abstract»

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  • On real-time capacity of event-driven data-gathering sensor networks

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2394 KB) |  | HTML iconHTML  

    Network capacity is a critical feature of wireless ad hoc and sensor networks. It is particularly challenging to determine network capacity when combined with other performance objectives such as timeliness. This paper investigates real-time capacity for event-driven data-gathering sensor networks with the unbalanced many-to-one traffic pattern. First, we compute the average allowable throughputs of nodes for a given event distribution, based on which we then leverage results of queuing theory to estimate the per-hop delays. We develop a new slack time distribution scheme for the unbalanced many-to-one traffic pattern, and prove it optimal in terms of the per-hop success probability. Here the per-hop success probability is defined as the probability for a packet to meet its sub-deadlines at each hop. Finally, we define the network-wide real-time capacity, i.e., given a threshold for the per-hop success probability, how much data (in bit per second) can be delivered to the sink node meeting their deadlines. For these research results, we provide some application scenarios, including configuring packet deadlines or verifying a specific deadline configuration, setting a packet's priority for dynamic scheduling, and trading the reliability of real-time data delivery for capacity efficiency etc. We also study two special cases of WSNs, the chain model and the continuous model. Our slack distribution scheme yields consistent or similar results for these two special cases as that of past works, but is more adaptive by supporting more generic cases. View full abstract»

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  • EcoPlex: Empowering compact wireless sensor platforms via roaming and interoperability support

    Publication Year: 2009 , Page(s): 1 - 9
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (11521 KB) |  | HTML iconHTML  

    EcoPlex is an infrastructure that enables simple wireless platforms to participate seamlessly in a feature-rich, wireless ad hoc network. EcoPlex consists of gateways that are responsible for handoff support for mobility and high data rate without burdening the simple nodes to implement multi-hop protocols. The gateways also create virtual identities for simpler nodes to enable their participation in the feature-rich network without adding complexity to them. We demonstrate the feasibility of this idea with the ultra-compact wireless sensor platform called Eco to participate as virtual nodes in a fully general ZigBee network. Experimental results show EcoPlex to be efficient and scalable. The enhanced mobility and interoperability are added to the Eco platform at the infrastructure level, all with minimal node complexity. View full abstract»

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  • Adaptive wireless services for augmented environments

    Publication Year: 2009 , Page(s): 1 - 8
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (9916 KB) |  | HTML iconHTML  

    This paper presents a system that combines mobile services, ubiquitous computing, and augmented reality concepts in order to bring the kind of information-rich environment, which is currently limited to computer screens, to the physical world. This objective is achieved by constructing an architecture based on existing wireless Web application and sensor network technologies. Users of the system as well as objects in the environment are associated with individual sensors. The system collects proximity information between objects and users, which is then used by the Web application server to provide adaptive services. The users then access these location-based services over the wireless network using a standard Web browser on their mobile device, e.g. smart phone. Unlike existing GPS-based solutions, this approach allows for a proximity resolution of approximately one meter inside buildings and rooms. Thus, the augmented objects in the surrounding environment of the users become local hubs of interactive services, creating an information-rich environment that is similar to the one on the Internet. The system presented, which can be built using already existing technologies, has widespread potential applications in, for example, elderly care, education, and commerce. View full abstract»

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  • MOBIX: System for managing mobility using information exchange

    Publication Year: 2009 , Page(s): 1 - 10
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (4256 KB) |  | HTML iconHTML  

    It is evident that mobile devices of the future will have multiple wireless interfaces. For small, energy-constrained devices, determining network availability by keeping all radio interfaces turned on at all times will negatively impact battery lifetime even when these interfaces are idle. Predicting future network availability from user history requires a period of training and learning user habits. This method will fail when users deviate from their routines constantly or move to locations not visited before. We propose a different approach to determining network availability of mobile nodes which leverages on the fact that nodes on the move will meet other nodes who will be able to share conditions of networks they have recently encountered. This paper presents MOBIX, a system where nodes exchange information about network conditions using short-range communication such as Bluetooth. Our simulation results show that the required number of nodes needed for 100% success is not unrealistic of densely populated metropolitan areas. Even with relatively low population densities, we can expect a data store hit more than 50% of the time. Although our evaluation used WiFi, our scheme can easily be extended for other technologies such as GSM and WiMax. View full abstract»

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  • Extracting Co-locator context

    Publication Year: 2009 , Page(s): 1 - 7
    Cited by:  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1941 KB) |  | HTML iconHTML  

    Having reliable context sources is very important for context-aware applications and the devices around a user can be a useful context for many applications. While the importance of `devices around' as a context has been highlighted many times, to the best of our knowledge, there is no systematic mechanism reported to identify and capture this context. In this paper we report our mechanism for extracting patterns that we call co-locators from the surrounding Bluetooth devices. The co-locator context can then be used as an indication about the user's surroundings. The context can be directly associated with user behavior in the surroundings, which in turn can be used for recommendation purposes. The context can also be used as a supplemental location indicator in the absence of other location mechanisms such as GPS. We then show that our experimental results support the value of using extracted co-locator patterns as good supplemental location indicators for several applications. View full abstract»

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  • DiaSim: A parameterized simulator for pervasive computing applications

    Publication Year: 2009 , Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (7742 KB) |  | HTML iconHTML  

    Pervasive computing applications involve both software concerns, like any software system, and integration concerns, for the constituent networked devices of the pervasive computing environment. This situation is problematic for testing because it requires acquiring, testing and interfacing a variety of software and hardware entities. This process can rapidly become costly and time-consuming when the target environment involves many entities. This paper introduces DiaSim, a simulator for pervasive computing applications. To cope with widely heterogeneous entities, DiaSim is parameterized with respect to a description of a target pervasive computing environment. This description is used to generate both a programming framework to develop the simulation logic and an emulation layer to execute applications. Furthermore, a simulation renderer is coupled to DiaSim to allow a simulated pervasive system to be visually monitored and debugged. DiaSim has been implemented and used to simulate various pervasive computing systems in different application areas, demonstrating the generality of our parameterized approach. View full abstract»

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  • Flockfs, a moderated group authoring system for wireless workgroups

    Publication Year: 2009 , Page(s): 1 - 10
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (4812 KB) |  | HTML iconHTML  

    This paper describes the design and implementation of a group authoring system for wireless users. Our analysis of the behavior of various groupware systems using wireless user availability traces showed that prior systems would have performed poorly, especially during peak availability durations when many group members were simultaneously available. These results motivate our design choices. flockfs maintains one updateable copy of the shared content on each group member's node. It also hoards read-only copies of each of these updateable copies in any interested group member's node. The various copies are reconciled using a moderation operation; each group member manually incorporates updates from all the other group members into their own copy. The various document versions will eventually converge into a single version through successive moderations. The system assists with this process by automatically logging the provenance of all causal reads of contents from other replicas into the author versions. A prototype userspace file system implementation of flockfs exhibits acceptable file system performance and update propagation latency. View full abstract»

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