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  • 1.
    Andersson, Göran
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Västberg, Anders
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Energy efficient heterogeneous network deployment with cell DTX2016In: 2016 IEEE International Conference on Communications (ICC),, IEEE, 2016, p. 1-6Conference paper (Refereed)
    Abstract [en]

    This paper evaluates different means of reducing power consumption of macro base stations (BS) and heterogeneous mobile network deployments (HetNet) considering the time dimension. These approaches are based on the same idea of reducing the load of heavily loaded macro cells and putting them to discontinuous transmission (DTX) mode during the time of inactivity by either (1) macro cell densification or (2) offloading traffic to small cells. Activity factor of a BS is defined as the fraction of time the BS is transmitting over a fixed time period. It is shown that by macro cell layer network densification, the average daily area power consumption can be reduced by up to 73 % with the use of cell DTX. However, reducing the activity factor by macro layer densification is not cost effective, as already demonstrated in previous studies. Alternatively, by adding small cells and enabling their DTX capability, power consumption can be reduced by up to 29 %. Adding small cells is especially effective in terms of energy savings, when users are distributed around hot spots, where additional coverage and capacity is required.

  • 2. Behrooz, Alireza
    et al.
    Devlic, Alisa
    A Context-Aware Privacy Policy Language for Controlling Access to Context Information of Mobile Users2012In: Security and Privacy in Mobile Information and Communication Systems: Third International ICST Conference, MobiSec 2011, Aalborg, Denmark, May 17-19, 2011, Revised Selected Papers, Springer Berlin Heidelberg, 2012, p. 25-39Conference paper (Refereed)
    Abstract [en]

    This paper introduces a Context-aware Privacy Policy Language (CPPL) that enables mobile users to control who can access their context information, at what detail, and in which situation by specifying their context-aware privacy rules. Context-aware privacy rules map a set of privacy rules to one or more user's situations, in which these rules are valid. Each time a user's situation changes, a list of valid rules is updated, leaving only a subset of the specified rules to be evaluated by a privacy framework upon arrival of a context query. In the existing context-dependent privacy policy languages a user's context is used as an additional condition parameter in a privacy rule, thus all the specified privacy rules have to be evaluated when a request to access a user's context arrives. Keeping the number of rules that need to be evaluated small is important because evaluation of a large number of privacy rules can potentially increase the response time to a context query. CPPL also enables rules to be defined based on a user's social relationship with a context requestor, which reduces the number of rules that need to be defined by a user and that consequently need to be evaluated by a privacy mechanism. This paper shows that when compared to the existing context-dependent privacy policy languages, this number of rules (that are encoded using CPPL) decreases with an increasing number of user-defined situations and requestors that are represented by a small number of social relationship groups.

  • 3.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Communication Systems, CoS.
    Context-addressed communication dispatch2009Licentiate thesis, monograph (Other academic)
    Abstract [en]

    This research concerns exploiting knowledge of the user's environment (i.e., context information) to enrich a user's communication making it more personal, by ensuring that the user receives only relevant messages and calls in his/her current context, and to facilitate more opportunities for communication interactions with people that are in the same context and that share the same interests as this user. We describe in this licentiate thesis the concepts of context-addressed messaging and context-aware session control that enable users to: (1) send messages to others based on their context, rather than their network address and (2) to initiate, adapt, and terminate user's communication sessions based on this user's current context, respectively. These concepts address questions such as: how to discover, select, and switch to an optimal communication means to meet varying user, contextual, communication, and device resource requirements and preferences. A key to solving these problems is to create a representation of the user's context-dependent preferences and to process the user's context-dependent preferences which are part of context triggers. These context triggers can initiate a communication event upon a particular context update. Additionally, in order to provide the described context-aware communication functions, these mechanisms need timely access to the acquired (desired) context information. This in turn raises a plethora of other questions, such as how to discover sensors that provide the desired context information; how to acquire raw context data from these sensors; how to abstract, process, and model this data to become "understandable" to applications and system components; and how to distribute this context to applications that are running on different nodes.

     

    This research is split into three different parts. The first part concerns investigating and implementing context management functions. As part of this research we propose a novel approach for context synthesis using context operators. We also propose a design architecture for context-aware middleware that mediates between the sensors and applications, and that is able to share and retrieve context from other nodes in the network. The second part of our research concerns our proposed mechanism for context-addressed messaging. To implement this mechanism we designed our own message format, called the Common Profile for Context-Addressed Messaging (CPCAM) that is able to use any high level context to compose a context-based address. Additionally, we proposed to use context-based filtering to find the correct message recipients and determine if this message is relevant to these potential message recipients in their current context, as well as to deliver this message to the recipients' preferred device that is adapted using their preferred communication means. At the end of this second part we design context-addressed messaging system operations on top of a SIP and SIMPLE-based network infrastructure. The third part of our research describes context-aware session control mechanisms using context switch and context trigger constructs. A context-switch selects an action from a set of context-dependent actions upon an incoming communication event based on the receiver's current context. In contrast, a context trigger initiates an action based on a context update and the user's preferences that are specified in this updated context. This part illustrates in several examples the context-aware session control mechanisms, i.e. the initiation of a communication session based on the match of a user's preferences and current context, as well as adaptation and (if necessary) termination of an ongoing communication session based upon the user's context-dependent preferences.

     

    The research leading to this licentiate has created network and system level models necessary for implementation of a context-addressed communication system that would enable users to easily design their own personalized, context-aware communication services. The necessary constructs and properties of these models are designed and analyzed in the thesis, as well as in conference papers and other documents published in the process of doing the research for this thesis. A number of remaining open issues and challenges have been outlined as part of the future work.

     

  • 4. Devlic, Alisa
    Extending CPL with context ontology2006Conference paper (Refereed)
    Abstract [en]

    Communication has always been an essential part of peo-ple's everyday life. Nowadays most of people would liketo be reachable on multiple devices at anytime, anyplace. As a consequence, there has been a need to know and exploit a user's availability for communication (so called presence information), so that he/she can control incoming callsand make the decision to accept this call or not based onthe user's current context. The appearance and acceptanceof Session Initiation Protocol (SIP) as a signalling protocol for next generation networks has opened the door for multiple services, such as Voice over IP (VoIP), chat, games,instant messaging, and other innovative communication services. Built on top of existing data communication networks, this has enabled easy integration of voice and data services. In this paper we present an idea on how to use the context information to enhance the power of existing SIP call control services, to enable users to have greater control over their incoming/outgoing calls. These services are implemented using Call Processing Language (CPL), a language to describe and control Internet Telephony Services. They are extended with context parameters to permit context-based decision making based on context ontology. We want to show how easy is to add new context parameters to the CPL and how complex criteria can be built using our solution.

  • 5.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    On Optimization of Quality of User Experience and Wireless Network Bandwidth in Video Content Delivery2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mobile video content today generates more than half of the mobile data traffic.The increasing popularity of mobile video on demand services poses great challenges to mobile operators and content providers. Frontmost, how to reduce the mobile video traffic load, while delivering high quality video content to mobile users without perceived quality degradations for the same (or cheaper) price? Battery lifetime represents another key factor of a user’s Quality of Experience(QoE). A lot of device energy is consumed by mobile network signalling and data transmission over new generation mobile communication systems. This thesis focuses on: (1) reducing the size of the video that is delivered to the enduser in the maximum achievable video quality, thus optimizing the wireless network bandwidth and the user-perceived QoE, and (2) reducing the energy consumption of a mobile device that is associated to data transfer over the radio interface, thus increasing the device’s battery lifetime. The main contributions have been given in providing the Over-the-Top video optimization and delivery schemes and recommendations on tuning their parameters in order to minimize the bandwidth and energy consumption of mobile video delivery, while maximizing the predictable user-perceived QoE. By preventing the video to be prefetched on low data rates and tuning the datarate threshold according to statistical properties of available data rates, we show that 20-70% of energy cost can be reduced by opportunistic prefetching, depending on the user’s pattern of available data rates. The data rate values ordered in time that have a large amount of serial correlation and low noise variance, or low average valueand high peak-to-mean ratio, are likely to yield the highest energy gains from content prefetching. Moreover, we show that energy gains are the largest when the threshold data rate is set close to an average data rate, due to the highest availability of data rates around this value, and for longer sleep time between the prefetching periods, which increases the probability of moving away from the areas with low data rates. Next, we focus on QoE-aware mobile video delivery solutions that are more bandwidth efficient without compromising the user-perceived video quality. They deliver a video over a varying data rate channel that is optimized for viewing on a mobile device in the highest perceptual video quality that can be achieved in the given video and network conditions. An optimized video consists of short segments in the minimum resolutions that satisfy the target perceptual video quality and have up to 60% reduced size compared to the video in the corresponding fixed video resolution, without perceptible quality difference. The delivery is performed by on demand download, context-aware prefetching, or in real time using the QoE-aware adaptive video streaming that runs over Dynamic Adaptive video Streaming over HTTP (DASH). By limiting the maximum bitrates of the requested video segments and using the remaining throughput to prefetch optimized video segments in advance of playout, we show that QoE-aware adaptive video streaming maintains a more stable perceptual video quality than DASH despite the fluctuations of the channel bandwidth, while using fewer number of bits, which improves a user-perceived QoE. The results of this thesis can help operators and content providers to reduce their costs and provide more content to their users at the same (or cheaper) price.

  • 6.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01).
    SIP-based context distribution: Does aggregation pay off?2010In: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 40, no 5, p. 35-46Article in journal (Refereed)
    Abstract [en]

    Context-aware applications need quickly access to current context information, in order to adapt their behavior before this context changes. To achieve this, the context distribution mechanism has to timely discover context sources that can provide a particular context type, then acquire and distribute context information from these sources to the applications that requested this type of information. This paper reviews the state-of-the-art context distribution mechanisms according to identified requirements, then introduces a resource list-based subscription/notification mechanism for context sharing. This SIP-based mechanism enables subscriptions to a resource list containing URIs of multiple context sources that can provide the same context type and delivery of aggregated notifications containing context updates from each of these sources. Aggregation of context is thought to be important as it reduces the network traffic between entities involved in context distribution. However, it introduces an additional delay due to waiting for context updates and their aggregation. To investigate if this aggregation actually pays off, we measured and compared the time needed by an application to receive context updates after subscribing to a particular resource list (using RLS) versus after subscribing to each of the individual context sources (using SIMPLE) for different numbers of context sources. Our results show that RLS aggregation outperforms the SIMPLE presence mechanism with 3 or more context sources, regardless of their context updates size. Database performance was identified as a major bottleneck during aggregation, hence we used in-memory tables & prepared statements, leading to up to 57% database time improvement, resulting in a reduction of the aggregation time by up to 34%. With this reduction and an increase in context size, we pushed the aggregation payoff threshold closer to 2 context sources.

  • 7. Devlic, Alisa
    et al.
    Erik, Klintskog
    Context retrieval and distribution in a mobile distributed environment2007Conference paper (Refereed)
    Abstract [en]

    Context-aware services are gaining momentum in mobile computing. To enable rapid development of context-aware services,context information has to be retrieved from the environment, modeled,processed, and distributed to these services. MIDAS is a European research project concerning 3G and beyond, which aims to dene and implement a platform to simplify and speed up the task of developing and deploying mobile applications and services. MIDAS context engine provides mechanisms to retrieve, model, synthesize, and distribute context information in a distributed, mobile environment. This paper presents a way to retrieve and distribute context information using context queries and triggers. A novel approach to perform context synthesis will be presented using operators.

  • 8.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Graf, A.
    Barone, P.
    Evaluation of context distribution methods via Bluetooth and WLAN: Insights gained while examining Battery Power Consumption2008In: MobiQuitous 2008 - 5th International ICST Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services, 2008Conference paper (Refereed)
    Abstract [en]

    In a traditional context-aware system, most context information is local to a device. However, we may need access to context information from outside the device. Increasingly mobile electronic devices are equipped with Bluetooth and/or WLAN network interfaces. Both of these technologies enable ad hoc discovery & networking. In this paper we evaluate the use of these technologies for context distribution within a local area (i.e., limited to a single hop). Using Bluetooth, we begin by discovering devices using Bluetooth's discovery protocol, collect their context information, create an XML file containing this information, and distribute this file to all discovered devices, such that every device now has the same context information. Next we perform the same discovery, collect, and distribute functions, but using WLAN. In each case we have performed the cycle of operations starting with a fully charged battery and continuing until the device was not able to utilize the selected wireless interface any longer. Finally we compare both approaches to context distribution in terms of battery power consumption. We observe that Bluetooth consumes 2-6 times more energy for transmission of a 1MB file to two devices than to discover these two devices. Furthermore, the transfer of this file is two times slower than WLAN, and we must unicast this file to each device. Multicasting via WLAN proved to be less energy consuming than the Bluetooth transmission, if data is to be sent to more than three users. In addition, the energy to discover 2 devices along with their services using Bluetooth consumed 52 times more energy than to receive the same amount of data via a WLAN multicast. Thus, this paper shows that it is more energy efficient to distribute context knowledge to other devices, than having each device learn this information itself. Finally, we give equations for calculating the battery power consumption of transmitting data using any protocol that runs over Bluetooth or over WLAN.

  • 9.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Kamaraju, Pavan
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Segall, Zary
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Tollmar, Konrad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    QoE-aware optimization for video delivery and storage2015In: 2015 IEEE 16th International Symposium on "A World of Wireless, Mobile and Multimedia Networks" (WoWMoM) 2015, Boston, MA, USA, 2015, p. 1-10Conference paper (Refereed)
    Abstract [en]

    The explosive growth of Over-the-top (OTT) online video strains capacity of operators’ networks, which severely threatens video quality perceived by end users. Since video is very bandwidth consuming, its distribution costs are becoming too high to scale with network investments that are required to support the increasing bandwidth demand. Content providers and operators are searching for solutions to reduce this video traffic load, without degrading their customers’ perceived Quality ofExperience (QoE). This paper proposes a method that can programmatically optimize video content for desired QoE accordingto perceptual video quality and device display properties, while achieving bandwidth and storage savings for content providers, operators, and end users. The preliminary results obtained with Samsung Galaxy S3 phone show that up to 60% savings can be achieved by optimizing movies without compromising the perceptible video quality, and up to 70% for perceptible, but not annoying video quality difference. Tailoring video optimization to individual user perception can provide seamless QoE delivery across all users, with a low overhead (i.e., 10%) required to achieve this goal. Finally, two applications of video optimization: QoE-aware delivery and storage, are proposed and examined.

  • 10.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Kamaraju, Pavan
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Segall, Zary
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Tollmar, Konrad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Towards QoE-aware adaptive video streaming2016In: 2015 IEEE 23rd International Symposium on Quality of Service (IWQoS), IEEE, 2016, p. 75-76, article id 7404713Conference paper (Refereed)
    Abstract [en]

    This paper describes a novel QoE-aware adaptive video streaming method that enhances the viewing experience on mobile devices and reduces cellular network bandwidth consumed by Dynamic Adaptive Streaming over HTTP (DASH) by considering perceptual video quality and data rate channel conditions in the bitrate adaptation process. By streaming an optimized video for the particular video quality and channel conditions toa mobile device, we can improve the worst video qualities causedby DASH streaming and reduce quality variations using fewer number of bits.

  • 11.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01). Appear Networks, Sweden.
    Koziuk, M.
    Horsman, W.
    Synthesizing context for a sports domain on a mobile device2008In: 3rd European Conference on Smart Sensing and Context, EuroSSC 2008, 2008, p. 206-219Conference paper (Refereed)
    Abstract [en]

    In ubiquitous computing environments there are an increasing number and variety of devices that can generate context data. The challenge is to timely acquire, process, and deliver these data to context-aware applications. The role of context synthesis is to generate new knowledge, as a result of a reasoning process applied to context information that is already present in the system. The success of this mechanism mainly depends on the response time that the end-user or an application must wait for the response to a context query. This paper describes and evaluates an approach to context synthesis on a mobile device to be used by a set of applications in a sports domain. A scenario based on a live race at the Super Prestige Cyclocross in Gieten, Netherlands demonstrates the use of context synthesis to dynamically compose gaps and groups of cyclists in order to provide a nearly real-time virtual ranking service.

  • 12.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Kamaraju, Pavan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Segall, Zary
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Tollmar, Konrad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Energy consumption reduction via context-aware mobile video pre-fetching2012In: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012, IEEE , 2012, p. 261-265Conference paper (Refereed)
    Abstract [en]

    The arrival of smartphones and tablets, along with a flat rate mobile Internet pricing model have caused increasing adoption of mobile data services. According to recent studies, video has been the main driver of mobile data consumption, having a higher growth rate than any other mobile application. However, streaming a medium/high quality video files can be an issue in a mobile environment where available capacity needs to be shared among a large number of users. Additionally, the energy consumption in mobile devices increases proportionally with the duration of data transfers, which depend on the download data rates achievable by the device. In this respect, adoption of opportunistic content pre-fetching schemes that exploit times and locations with high data rates to deliver content before a user requests it, has the potential to reduce the energy consumption associated with content delivery and improve the user's quality of experience, by allowing playback of pre-stored content with virtually no perceived interruptions or delays. This paper presents a family of opportunistic content pre-fetching schemes and compares their performance to standard on-demand access to content. By adopting a simulation approach on experimental data, collected with monitoring software installed in mobile terminals, we show that content pre-fetching can reduce energy consumption of the mobile devices by up to 30% when compared to the on demand download of the same file, with a time window of 1 hour needed to complete the content prepositioning.

  • 13.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Segall, Zary
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Tollmar, Konrad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Evaluation of energy profiles for mobile video prefetching in generalized stochastic access channels2014In: Mobile and Ubiquitous Systems: Computing, Networking, and Services: 10th International Conference, MOBIQUITOUS 2013, Tokyo, Japan, December 2-4, 2013, Revised Selected Papers, Springer, 2014, p. 209-223Conference paper (Refereed)
    Abstract [en]

    This paper evaluates the energy cost reduction of Over-The-Top mobile video content prefetching in various network conditions. Energy cost reduction is achieved by reducing the time needed to download content over the radio interface by prefetching data on higher data rates, compared to the standard on demand download. To simulate various network conditions and user behavior, a stochastic access channel model was built and validated using the actual user traces. By changing the model parameters, the energy cost reduction of prefetching in different channel settings was determined, identifying regions in which prefetching is likely to deliver the largest energy gains. The results demonstrate that the largest gains (up to 70%) can be obtained for data rates with strong correlation and low noise variation. Additionally, based on statistical properties of data rates, such as peak-to-mean and average data rate, prefetching strategy can be devised enabling the highest energy cost reduction that can be obtained using the proposed prefetching scheme.

  • 14.
    Devlic, Alisa
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01). Appear Networks, Sweden .
    Reichle, R.
    Wagner, M.
    Pinheiro, M. K.
    Vanrompay, Y.
    Berbers, Y.
    Valla, M.
    Context inference of users' social relationships and distributed policy management2009In: 7th Annual IEEE International Conference on Pervasive Computing and Communications, PerCom 2009, IEEE , 2009, p. 778-785Conference paper (Refereed)
    Abstract [en]

    Inference of high-level context is becoming crucial in development of context-aware applications. An example is social context inference i.e., deriving social relations based upon the user's daily communication with other people. The efficiency of this mechanism mnaimily depends on the method(s) used to draw inferences based on existing evidence and sample information, such as a training data. Our approach uses rule-based data mining. Bayesian network inference, and user feedback to compute the probabilities of another user being in the specific social relationship with a user whose daily communication is logged by a mobile phone. In addition, a privacy mechanism is required to ensure the user's personal integrity and privacy when sharing this user's sensitive context data. Therefore, the derived social relations are used to define a user's policies for context access control, which grant the restricted context information scope depending on the user's current context. Finally, we propose a distributed architecture capable of managing this context information based upon these context access policies.

  • 15.
    Karapantelakis, Athanasios
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Communication Systems, CoS.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Communication Systems, CoS.
    Zarify, Mohammad
    Khamit, Saltanat
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Communication Systems, CoS.
    Printing in Ubiquitous Computing Environments2009In: UBIQUITOUS INTELLIGENCE AND COMPUTING, PROCEEDINGS / [ed] Zhang D; Portmann M; Tan AH; Indulska J, 2009, Vol. 5585, p. 83-98Conference paper (Refereed)
    Abstract [en]

    Document printing has long been considered an indispensable part of the workspace. While this process is considered trivial and simple for environments where resources are ample (e.g. desktop computers connected to printers within a corporate network), it becomes complicated when applied in a mobile context. Contemporary mobile devices have the computational resources required for document processing and are affordable enough for an increasingly large number of users. Therefore, document printing using mobile devices is now both technically feasible and relevant to users' needs. In this study, we present an infrastructure for document printing using mobile devices. In order to realize the vision, we utilize an existing set of network protocols, a set of common programming languages, standard concepts of ubiquitous computing, and machine learning, in order to automate the printing process.

  • 16. Kirsch-Pinheiro, M.
    et al.
    Vanrompay, Y.
    Victor, K.
    Berbers, Y.
    Valla, M.
    Frà, C.
    Mamelli, A.
    Barone, P.
    Hu, X.
    Devlic, Alisa
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01). Appear Networks, Sweden.
    Panagiotou, Georgios
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01). Appear Networks, Sweden.
    Context grouping mechanism for context distribution in ubiquitous environments2008In: OTM 2008 Confederated International Conferences CoopIS, DOA, GADA, IS, and ODBASE 2008, 2008, no PART 1, p. 571-588Conference paper (Refereed)
    Abstract [en]

    Context distribution is a key aspect for successful applications within mobile and ubiquitous computing environments. In such environments, context information is acquired by several and multiple context sensors distributed over the environment. Applications collect and react to these data, according to predefined adaptation mechanisms. The success of these mechanisms depends on the availability of context information, which is disseminated over the network. However, in practice, only a fraction of the observable context information is required by the adaptation mechanisms. Moreover, for privacy reasons, it is important to delimitate a scope for context dissemination. In this work we address these issues by proposing a context grouping mechanism which allows the definition of groups based on the context characteristics. Each group is defined by these characteristics and delimitate a given context information set that can be distributed among group members. This approach of context grouping acts as a two-fold mechanism. On the one hand, it controls and organizes context distribution over a peer-to-peer network. On the other hand, it proposes a primary and low-level privacy mechanism for context distribution, which is an important aspect influencing context distribution.

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