[Show abstract][Hide abstract] ABSTRACT: Battery State of Charge (SOC) estimation is a fundamental component of today's smartphones that affects the internal processes and observable behavior of the devices. This article systematically investigates and analyzes the SOC estimation techniques in smartphones. First, we discover that the voltage curve of a given device implicitly captures the usable capacity of the battery while charging the mobile devices.
Second, we observe that today's SOC estimation techniques do not model battery capacity loss sufficiently to accurately capture the usable capacity. Finally, we report findings based on battery analytics of 2077 devices that validate the relationship between battery voltage and the usable capacity of a device. The presented results enable the development of more accurate battery gauges and metering solutions thus resulting in better power-saving decisions, recommendations for the users, and most importantly more reliable systems.
Accepted in HotPower'2015, Monterey, California; 10/2015
[Show abstract][Hide abstract] ABSTRACT: Physical spaces are packed with opportunities, complexities, and of course, people. Many business and social opportunities are missed, and complexities can highly degrade people's experiences in these spaces. Pervasive computing has yet to be widely exploited in physical spaces in the same way that the ubiquitous Web and smartphones have been exploited--effectively revolutionizing the way we interact with others, work, and conduct our daily lives. With the advent of the Internet of Things as a major force of change in industry and the rise of wearable computing for consumers, the time is right for revisiting the notion of a smart space. The articles in this special issue consider new technologies and approaches for developing pervasive smart spaces.
[Show abstract][Hide abstract] ABSTRACT: An OpenStack based private cloud with the Cluster File System has been built and used with both CMS analysis and Monte Carlo simulation jobs in the Datacenter Indirection Infrastructure for Secure High Energy Physics (DII-HEP) project. On the cloud we run the ARC middleware that allows running CMS applications without changes on the job submission side. Our test results indicate that the adopted approach provides a scalable and resilient solution for managing resources without compromising on performance and high availability.
Journal of Physics Conference Series 05/2015; 608(1):012010. DOI:10.1088/1742-6596/608/1/012010
[Show abstract][Hide abstract] ABSTRACT: Many applications, such as product promotion advertisement and traffic congestion notification, benefit from opportunistic content exchange in Delay Tolerant Networks (DTNs). An important requirement of such applications is timely delivery. However, the intermittent connectivity of DTNs may significantly delay content exchange, and cannot guarantee timely delivery. The state-of-the-arts capture mobility patterns or social properties of mobile devices. Such solutions do not capture patterns of delivered content in order to optimize content delivery. Without such optimization, the content demanded by a large number of subscribers could follow the same forwarding path as the content by only one subscriber, leading to traffic congestion and packet drop. To address the challenge, in this paper, we develop a solution framework, namely Ameba, for timely delivery. In detail, we first leverage content properties to derive an optimal routing hop count of each content to maximize the number of needed nodes. Next, we develop node utilities to capture interests, capacity and locations of mobile devices. Finally, the distributed forwarding scheme leverages the optimal routing hop count and node utilities to deliver content towards the needed nodes in a timely manner. Illustrative results verify that Ameba achieves comparable delivery ratio as Epidemic but with much lower overhead.
IEEE Transactions on Mobile Computing 04/2015; 14(4):755-769. DOI:10.1109/TMC.2014.2330296 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Beyond offering the widely used keyword search function, many peer-to-peer systems nowadays support the subscription function. For example, Vuze allows users to create subscription filters based on the keyword search. Given the subscription, episodic or related content will be delivered to the users whenever new episodes are available. Unfortunately, these applications suffer from the downsides, for example, high network traffic in the nodes maintaining popular terms. In this paper, we propose the MTAF mechanism to overcome the issues. The key of MTAF is to carefully select a subset of terms without incurring false negatives and to forward the content item toward the home nodes of such selected terms for low content forwarding cost. Experimental results based on real datasets indicate that the proposed solutions are efficient compared to existing approaches. In particular, the similarity-based replication of filters is shown to mitigate the effect of hot spots that arise due to the fact that some document terms are substantially more popular than the others.
IEEE Transactions on Parallel and Distributed Systems 04/2015; 26(4):1071-1084. DOI:10.1109/TPDS.2014.5 · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The emerging mobile cloud has expanded the horizon of application development and deployment with techniques such as code offloading. While offloading has been widely considered for saving energy and increasing responsiveness of mobile devices, the technique still faces many challenges pertaining to practical usage. In this article, we adopt a systemic approach for analyzing the components of a generic code offloading architecture. Based on theoretical and experimental analysis, we identify the key limitations for code offloading in practice and then propose solutions to mitigate these limitations. We develop a generic architecture to evaluate the proposed solutions. The results provide insights regarding the evolution and deployment of code offloading.
[Show abstract][Hide abstract] ABSTRACT: Nowadays, we experience an abundance of Internet-of-Things (IoT) middleware
solutions that provide connectivity for sensors and actuators to the Internet.
To gain a widespread adoption, these middleware solutions, referred to as
platforms, have to meet the expectations of different players in the IoT
ecosystem, including device providers, application developers, and end-users,
among others. In this article, we evaluate a representative sample of these
platforms, both proprietary and open-source, on the basis of their ability to
meet the ecosystem expectations. The evaluation is completed by a gap analysis
of the current IoT landscape with respect to (i) the support of heterogeneous
hardware, (ii) the capabilities of the platform for data management, (iii) the
support of application developers, (iv) the extensibility of the different
platforms for the formation of ecosystems, as well as (v) the availability of
dedicated marketplaces to the IoT. The gap analysis aims to highlight the
deficiencies of today's solutions to improve their integration to tomorrow's
ecosystem. Based on the result of the analysis, we conclude this article with a
list of recommendations for extending these IoT platforms in order to fill in
[Show abstract][Hide abstract] ABSTRACT: This document regroups a representative, but non-exhaustive, list of
contemporary IoT platforms. The platforms are ordered alphabetically. The aim
of this document is to provide the a quick review of current IoT platforms, as
well as relevant information.
[Show abstract][Hide abstract] ABSTRACT: This article describes an experimental course where students developed Internet of Things device prototypes to improve the upkeep of an urban rooftop greenhouse. With the help of a problem-based learning approach, students were first familiarized with their new learning environment and encouraged to find issues that could be improved as a meaningful personal learning experience. A project-based learning approach was then used to develop innovative solutions while validating their relevance in collaboration with gardeners that were taking care of the greenhouse. As a result, a number of practical applications for monitoring the state of the greenhouse were developed along with new practices for its maintenance. As participants were given the freedom to choose both the topic and technologies to work with, the course provided a learning experience that was tailored to suit personal interests and competences. Having the common background story allowed students to practice teamwork skills and collaborative software engineering in the context of the emerging topic of Internet of Things.
SIGCSE '15 Proceedings of the 46th ACM Technical Symposium on Computer Science Education; 01/2015
[Show abstract][Hide abstract] ABSTRACT: A major challenge of future mobile networks is providing the needed elastic scaling to the increased traffic demand, number of users and applications with acceptable cost. Another challenge is suitability for numerous communications applications while curbing unwanted traffic on the air interface and the mobile devices. This paper proposes a vision of how these challenges can be met by applying the concept of Software Defined Networking (SDN) to mobile networks. We also discuss the needed migration path that minimizes unnecessary replacement investments. While we have verified some key parts of the vision with experiments, we realize that the effectiveness of the proposed approach depends on the adoption of SDN technology for other purposes so that mass production of SDN switches leads to significant economies of scale. The paper shows how we can model mobile networks using SDN concepts and migrate the 3GPP mobile architecture to SDN. The resulting control plane of the mobile architecture consists of a group of SDN applications starting from the base stations i.e., virtual eNodeBs, Backhaul transport, Mobility management, Access, Caching, Monitoring, and Services delivery. The data plane consists of simplified access points and SDN and Carrier Grade Ethernet switches. Our experiments are based on using OpenFlow as the interface between the planes.
[Show abstract][Hide abstract] ABSTRACT: Human mobility has been empirically observed to exhibit Levy flight
characteristics and behaviour with power-law distributed jump size. The
fundamental mechanisms behind this behaviour has not yet been fully explained.
In this paper, we analyze urban human mobility and we propose to explain the
Levy walk behaviour observed in human mobility patterns by decomposing them
into different classes according to the different transportation modes, such as
Walk/Run, Bicycle, Train/Subway or Car/Taxi/Bus. Our analysis is based on two
real-life GPS datasets containing approximately 10 and 20 million GPS samples
with transportation mode information. We show that human mobility can be
modelled as a mixture of different transportation modes, and that these single
movement patterns can be approximated by a lognormal distribution rather than a
power-law distribution. Then, we demonstrate that the mixture of the decomposed
lognormal flight distributions associated with each modality is a power-law
distribution, providing an explanation to the emergence of Levy Walk patterns
that characterize human mobility patterns.
[Show abstract][Hide abstract] ABSTRACT: Wireless data transmission consumes a significant part of the overall energy consumption of smartphones, due to the popularity of Internet applications. In this paper, we investigate the energy consumption characteristics of data transmission over Wi-Fi, focusing on the effect of Internet flow characteristics and network environment. We present deterministic models that describe the energy consumption of Wi-Fi data transmission with traffic burstiness, network performance metrics like throughput and retransmission rate, and parameters of the power saving mechanisms in use. Our models are practical because their inputs are easily available on mobile platforms without modifying low-level software or hardware components. We demonstrate the practice of model-based energy profiling on Maemo, Symbian, and Android phones, and evaluate the accuracy with physical power measurement of applications including file transfer, web browsing, video streaming, and instant messaging. Our experimental results show that our models are of adequate accuracy for energy profiling and are easy to apply.
IEEE Transactions on Mobile Computing 08/2014; 13(8):1760-1773. DOI:10.1109/TMC.2013.51 · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The challenge of providing a resilient and scalable computational and data management solution for massive scale research environments requires continuous exploration of new technologies and techniques. In this project the aim has been to design a scalable and resilient infrastructure for CERN HEP data analysis. The infrastructure is based on OpenStack components for structuring a private Cloud with the Gluster File System. We integrate the state-of-the-art Cloud technologies with the traditional Grid middleware infrastructure. Our test results show that the adopted approach provides a scalable and resilient solution for managing resources without compromising on performance and high availability.
Journal of Physics Conference Series 06/2014; 513(6):062047. DOI:10.1088/1742-6596/513/6/062047
[Show abstract][Hide abstract] ABSTRACT: In recent years we have seen a fast change in the networking industry: leading by the Software Defined Networking (SDN) paradigm that separates the control plane from the data plane to enable programmability and centralized control of the network infrastructure, the SDN design not only simplifies the network management but also accelerates the innovation speed of deploying advanced network applications. Meanwhile, the landscape of the wireless and mobile industry is changing dramatically as well. Given the advance of wireless technologies such as 4G and WiFi offering a pervasive Internet access, the traffic growth from the smartphone-alike devices has placed an increasing strain on the mobile network infrastructure and infringed the profit. Since the demand is increasing together with the growth of mobile users, the incumbent legacy infrastructure is already calling for an upgrade to overcome its existing limitations in terms of network management and security. In this paper, we advocate that the way forward is to integrate SDN and fully utilize its feature to solve the problem. As the security issue has raise serious concern in the networking community recently, we focus on the security aspect and investigate how to enhance the security with SDN for the wireless mobile networks.
[Show abstract][Hide abstract] ABSTRACT: The fast increase of mobile traffic from smartphone-like devices has created a huge pressure for the cellular operators to manage the network infrastructure and resources. Offloading the mobile traffic to alternative networks such as WiFi is sought as a promising direction to solve this problem cost-effectively. According to our study and experimental findings, existing research proposals are lack of concern for the complexity of network deployment and device limitations, which impedes the solution deployment. To overcome such challenge, we propose SoftOffload, a programmable framework for collaborative mobile traffic offloading. SoftOffload takes the advantage of software defined networking (SDN) paradigm in terms of openness and extensibility. We have implemented the first prototype utilising the open source Floodlight platform.
12th ACM International Conference on Mobile Systems, Applications, and Services (ACM MobiSys), 2014, Bretton Woods, NH, USA; 06/2014
[Show abstract][Hide abstract] ABSTRACT: Mobile malware is on the rise as the global number of smartphone users grows exponentially. Traditional malware detection and scanning tools only detect malware when devices are actually infected. In previous work, we saw that the presence of applications that occur often with known malware can indicate not only infection status but also potential risk of infection. In this paper, we present Doctor - a malware prognosis application based on crowd sourced data. Doctor includes a server component and an easy-to-use Android client application. Doctor visualizes the health of the device as a pie chart, slices representing applications. Each slice is split into four sections, corresponding to different lightweight indicators of infection. Sections of each slice are colored from green to red. The greater the amount of red, the greater the risk of infection. This front-end application provides users a new function for malware prognosis which is currently missing in existing mobile anti-malware tools.
2014 IEEE 34th International Conference on Distributed Computing Systems Workshops (ICDCSW); 06/2014
[Show abstract][Hide abstract] ABSTRACT: Multimedia streaming to mobile devices is challenging for two reasons. First, the way content is delivered to a client must ensure that the user does not experience a long initial playback delay or a distorted playback in the middle of a streaming session. Second, multimedia streaming applications are among the most energy hungry applications in smartphones. The energy consumption mostly depends on the delivery techniques and on the power management techniques of wireless access technologies (Wi-Fi, 3G, and 4G). In order to provide insights on what kind of streaming techniques exist, how they work on different mobile platforms, their efforts in providing smooth quality of experience, and their impact on energy consumption of mobile phones, we did a large set of active measurements with several smartphones having both Wi-Fi and cellular network access. Our analysis reveals five different techniques to deliver the content to the video players. The selection of a technique depends on the mobile platform, device, player, quality, and service. The results from our traffic and power measurements allow us to conclude that none of the identified techniques is optimal because they take none of the following facts into account: access technology used, user behavior, and user preferences concerning data waste. We point out the technique with the best playback buffer configuration, which provides the most attractive trade-offs in particular situations.
Pervasive and Mobile Computing 05/2014; 16. DOI:10.1016/j.pmcj.2014.05.004 · 2.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: With bounded receive buffers, the aggregate bandwidth of multipath transmission degrades significantly in the presence of path heterogeneity. The performance could even be worse than that of single-path TCP, undermining the advantage gained by using multipath transmit. Furthermore, multipath transmission also suffers from delay and jitter even with large receive buffers.
In order to tolerate the path heterogeneity when the receive buffer is bounded, we propose a new multipath TCP protocol, namely SC-MPTCP, by integrating linear systematic coding into MPTCP. In SC-MPTCP, we make use of coded packets as redundancy to counter against expensive retransmissions. The redundancy is provisioned into both proactive and reactive data. Specifically, to send a generation of packets, SC-MPTCP transmits proactive redundancy first and then delivers the original packets, instead of encoding all sent-out packets as all the existing coding solutions have done. The proactive redundancy is continuously updated according to the estimated aggregate retransmission ratio. In order to avoid the proactive redundancy being underestimated, the pre-blocking warning mechanism is utilized to retrieve the reactive redundancy from the sender.
We use an NS-3 network simulator to evaluate the performance of SC-MPTCP with and without the coupled congestion control option. The results show that with bounded receive buffers, MPTCP achieves less than 20%20% of the optimal goodput with diverse packet losses, whereas SC-MPTCP approaches the optimal performance with significantly smaller receive buffers. With the help of systematic coding, SC-MPTCP reduces the average buffer delay of MPTCP by at least 80%80% in different test scenarios. We also demonstrate that the use of systematic coding could significantly reduce the arithmetic complexity compared with the use of non-systematic coding.
[Show abstract][Hide abstract] ABSTRACT: At the age of Web 2.0, Web content becomes live, and users would like to automatically receive content of interest. Popular RSS subscription approach cannot offer fine-grained filtering approach. In this paper, we propose a personalized subscription approach over the live Web content. The document is represented by pairs of terms and weights. Meanwhile, each user defines a top-k continuous query. Based on an aggregation function to measure the relevance between a document and a query, the user continuously receives the top-k most relevant documents inside a sliding window. The challenge of the above subscription approach is the high processing cost, especially when the number of queries is very large. Our basic idea is to share evaluation results among queries. Based on the defined covering relationship of queries, we identify the relations of aggregation scores of such queries and develop a graph indexing structure (GIS) to maintain the queries. Next, based on the GIS, we propose a document evaluation algorithm to share query results among queries. After that, we re-use evaluation history documents, and design a document indexing structure (DIS) to maintain the history documents. Finally, we adopt a cost model-based approach to unify the approaches of using GIS and DIS. The experimental results show that our solution outperforms the previous works using the classic inverted list structure.
World Wide Web 01/2014; 17(1). DOI:10.1007/s11280-012-0191-3 · 1.47 Impact Factor