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  • 1.
    Palm, Emanuel
    et al.
    Luleå tekniska universitet.
    Mitra, Karan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A Bayesian system for cloud performance diagnosis and prediction2017Ingår i: Proceedings of the International Conference on Cloud Computing Technology and Science, CloudCom, Piscataway, NJ: IEEE Computer Society, 2017, 371-374 s., 7830706Konferensbidrag (Refereegranskat)
    Abstract [en]

    The stochastic nature of the cloud systems makes cloud quality of service (QoS) performance diagnosis and prediction a challenging task. A plethora of factors including virtual machine types, data centre regions, CPU types, time-of-the-day, and day-of-the-week contribute to the variability of the cloud QoS. The state-of-the-art methods for cloud performance diagnosis do not capture and model complex and uncertain inter-dependencies between these factors for efficient cloud QoS diagnosis and prediction. This paper presents ALPINE, a proof-of-concept system based on Bayesian networks. Using a real-life dataset, we demonstrate that ALPINE can be utilised for efficient cloud QoS diagnosis and prediction under stochastic cloud conditions

  • 2.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Ranjan, Rajiv
    Newcastle University.
    ALPINE: A Bayesian System For Cloud Performance Diagnosis And Prediction2017Ingår i: 2017 IEEE International Conference on Services Computing (SCC), Piscataway, NJ: IEEE, 2017, 281-288 s., 8034996Konferensbidrag (Refereegranskat)
    Abstract [en]

    Cloud performance diagnosis and prediction is a challenging problem due to the stochastic nature of the cloud systems. Cloud performance is affected by a large set of factors such as virtual machine types, regions, workloads, wide area network delay and bandwidth. Therefore, necessitating the determination of complex relationships between these factors. The current research in this area does not address the challenge of modeling the uncertain and complex relationships between these factors. Further, the challenge of cloud performance prediction under uncertainty has not garnered sufficient attention. This paper proposes, develops and validates ALPINE, a Bayesian system for cloud performance diagnosis and prediction. ALPINE incorporates Bayesian networks to model uncertain and complex relationships between several factors mentioned above. It handles missing, scarce and sparse data to diagnose and predict stochastic cloud performance efficiently. We validate our proposed system using extensive real data and show that it predicts cloud performance with high accuracy of 91.93%.

  • 3.
    Idowu, Samuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Applied Machine Learning: Forecasting Heat Load in District Heating System2016Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 133, 478-488 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Forecasting energy consumption in buildings is a key step towards the realization of optimized energy production, distribution and consumption. This paper presents a data driven approach for analysis and forecast of aggregate space and water thermal load in buildings. The analysis and the forecast models are built using district heating data unobtrusively collected from ten residential and commercial buildings located in Skellefteå, Sweden. The load forecast models are generated using supervised machine learning techniques, namely, support vector machine, regression tree, feed forward neural network, and multiple linear regression. The model takes the outdoor temperature, historical values of heat load, time factor variables and physical parameters of district heating substations as its input. A performance comparison among the machine learning methods and identification of the importance of models input variables is carried out. The models are evaluated with varying forecast horizons of every hour from 1 up to 48 hours. Our results show that support vector machine, feed forward neural network and multiple linear regression are more suitable machine learning methods with lower performance errors than the regression tree. Support vector machine has the least normalized root mean square error of 0.07 for a forecast horizon of 24 hour.

  • 4. Nanda, Rohan
    et al.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Mitra, Karan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    BayesForSG:: A Bayesian Model for Forecasting Thermal Load in Smart Grids2016Ingår i: SAC '16: Proceedings of the 31st Annual ACM Symposium on Applied Computing, New York: ACM Digital Library, 2016, 2135-2141 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Forecasting the thermal load demand for residential buildings assists in optimizing energy production and developing demand response strategies in a smart grid system. However, the presence of a large number of factors such as outdoor temperature, district heating operational parameters, building characteristics and occupant behavior, make thermal load forecasting a challenging task. This paper presents an efficient model for thermal load forecast in buildings with different variations of heat load consumption across both winter and spring seasons using a Bayesian Network. The model has been validated by utilizing the realistic district heating data of three residential buildings from the district heating grid of the city of Skellefteå, Sweden over a period of four months. The results from our model shows that the current heat load consumption and outdoor temperature forecast have the most influence on the heat load forecast. Further, our model outperforms state-of-the-art methods for heat load forecasting by achieving a higher average accuracy of 77.97% by utilizing only 10% of the training data for a forecast horizon of 1 hour.

  • 5. Ngo, Khoi
    et al.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Mitra, Karan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    IReHMo: An efficient IoT-Based Remote health Monitoring System for Smart Regions2016Ingår i: 2015 17th International Conference on E-Health Networking, Application and Services, HealthCom 2015: Boston, United States, 13 - 17 October 2015, Piscataway, NJ: IEEE Communications Society, 2016, 563-568 s., 7454565Konferensbidrag (Refereegranskat)
    Abstract [en]

    The ageing population worldwide is constantly rising, both in urban and regional areas. There is a need for IoT-based remote health monitoring systems that take care of the health of elderly people without compromising their convenience and preference of staying at home. However, such systems may generate large amounts of data. The key research challenge addressed in this paper is to efficiently transmit healthcare data within the limit of the existing network infrastructure, especially in remote areas. In this paper, we identified the key network requirements of a typical remote health monitoring system in terms of real-time event update, bandwidth requirements and data generation. Furthermore, we studied the network communication protocols such as CoAP, MQTT and HTTP to understand the needs of such a system, in particular the bandwidth requirements and the volume of generated data. Subsequently, we have proposed IReHMo - an IoT-based remote health monitoring architecture that efficiently delivers healthcare data to the servers. The CoAP-based IReHMo implementation helps to reduce up to 90% volume of generated data for a single sensor event and up to 56% required bandwidth for a healthcare scenario. Finally, we conducted a scalability analysis to determine the feasibility of deploying IReHMo in large numbers in regions of north Sweden.

  • 6. Louis, Baptiste
    et al.
    Mitra, Karan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    CloudSimDisk: Energy-Aware Storage Simulation in CloudSim2015Ingår i: 2015 IEEE/ACM 8th International Conference on Utility and Cloud Computing (UCC): Limassol, 7-10 Dec. 2015, Piscataway, NJ: IEEE Communications Society, 2015, 11-15 s., 7431390Konferensbidrag (Refereegranskat)
    Abstract [en]

    The cloud computing paradigm is continually evolving, and with it, the size and the complexity of its infrastructure. Assessing the performance of a cloud environment is an essential but an arduous task. Further, the energy consumed by data centers is steadily increasing and major components such as the storage systems need to be more energy efficient. Cloud simulation tools have proved quite useful to study these issues. However, these simulation tools lack mechanisms to study energy efficient storage in cloud systems. This paper contributes in the area of cloud computing by extending the widely used cloud simulator CloudSim. In this paper, we propose CloudSimDisk, a scalable module for modeling and simulation of energy-aware storage in cloud systems. We show how CloudSimDisk can be used to simulate energy-aware storage, and can be extended to study new algorithms for energy-awareness in cloud systems. Our simulation results proved to be in accordance with the analytical models that were developed to model energy consumption of hard disk drives in cloud systems. The source code of CloudSimDisk is also made available for the research community for further testing and development.

  • 7.
    Jimenez, Lara Lorna
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Simon, Miguel Gomez
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Kristiansson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Synnes, Kåre
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    CoMA: Resource Monitoring of Docker Containers2015Ingår i: Proceedings of the 5th International Conference on Cloud Computing and Services Science (CLOSER 2015), SCITEPRESS Digital Library , 2015, Vol. 1, 145-154 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This research paper presents CoMA, a Container Monitoring Agent, that oversees resource consumption of operating system level virtualization platforms, primarily targeting container-based platforms such as Docker. The core contribution is CoMA, together with a quantitative evaluation verifying the validity of the measurements reported by the agent for three metrics: CPU, memory and block I/O. The proof-of-concept is implemented for Docker-based systems and consists of CoMA, the Ganglia Monitoring System and the Host sFlow agent. This research is in line with the rising trend of container adoption which is due to the resource efficiency and ease of deployment. These characteristics have set containers in a position to topple virtual machines as the reigning virtualization technology in data centers.

  • 8.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Context-Aware QoE Modelling, Measurement and Prediction in Mobile Computing Systems2015Ingår i: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 14, nr 5, 920-936 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quality of Experience (QoE) as an aggregate of Quality of Service (QoS) and human user-related metrics will be the key success factor for current and future mobile computing systems. QoE measurement and prediction are complex tasks as they may involve a large parameter space such as location, delay, jitter, packet loss and user satisfaction just to name a few. These tasks necessitate the development of practical context-aware QoE models that efficiently determine relationships between user context and QoE parameters. In this paper, we propose, develop and validate a novel decision-theoretic approach called CaQoEM for QoE modelling, measurement and prediction. We address the challenge of QoE measurement and prediction where each QoE parameter can be measured on a different scale and may involve different units of measurement. CaQoEM is context-aware and uses Bayesian networks and utility theory to measure and predict users' QoE under uncertainty. We validate CaQoEM using extensive experimentation, user studies and simulations. The results soundly demonstrate that CaQoEM correctly measures range-defined QoE using a bipolar scale. For QoE prediction, an overall accuracy of 98.93\% was achieved using 10-fold cross validation in multiple diverse network conditions such as vertical handoffs, wireless signal fading and wireless network congestion.

  • 9.
    Granlund, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Holmlund, Patrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    EAP-Swift: An Efficient Authentication and Key Generation Mechanism for Resource Constrained WSNs2015Ingår i: International Journal of Distributed Sensor Networks, ISSN 1550-1329, E-ISSN 1550-1477, 460914Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Technological advances within the area of wireless sensor technology allow WSNs to be used in a increasing number of measurement scenarios. As new application areas are emerging, such as infrastructure monitoring and smart cities, the need for sensor mobility handling requires efficient and secure authentication protocols. This paper presents EAP-Swift, a novel EAP based authentication protocol with a focus on lightweight processing and faster response. It supports end-to-end session encryption key generation and mutual authentication. By utilizing lightweight hashing algorithms, the challenge-response authentication mechanism uses only two round trips to the AAA server for the complete authentication procedure leading to the reduction of latency by 33% compared to the baseline protocols. Further, using extensive experimentation, we validate that the authentication time can be kept below 250 ms and the power consumption can be kept below 15 mJ. Furthermore, we show that a battery lifetime of more than four years can be achieved when running the system on a regular button cell battery. Finally, the protocol was verified in terms of security using the AVISPA tool.

  • 10.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Granlund, Daniel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    M2C2: A Mobility Management System for Mobile Cloud Computing2015Ingår i: IEEE Wireless Communications and Networking Conference, 2015: WCNC 2015, 9-12 Mars 2015, New Orleans, LA, Piscataway, NJ: IEEE Communications Society, 2015, 1608-1613 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobile devices have become an integral part of our daily lives. Applications running on these devices may avail storage and compute resources from the cloud(s). Further, a mobile device may also connect to heterogeneous access networks (HANs) such as WiFi and LTE to provide ubiquitous network connectivity to mobile applications. These devices have limited resources (compute, storage and battery) that may lead to servicedisruptions. In this context, mobile cloud computing enables offloading of computing and storage to the cloud. However, applications running on mobile devices using clouds and HANs are prone to unpredictable cloud workloads, network congestion and handoffs. To run these applications efficiently the mobile device requires the best possible cloud and network resources while roaming in HANs. This paper proposes, develops and validates a novel system called M2C2 which supports mechanismsfor: i.) multihoming, ii.) cloud and network probing, and iii.) cloudand network selection. We built a prototype system and performed extensive experimentation to validate our proposed M2C2. Our results analysis shows that the proposed system supports mobility efficiently in mobile cloud computing.

  • 11.
    Granlund, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Holmlund, Patrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Opportunistic Mobility Support for Resource Constrained Sensor Devices in Smart Cities2015Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, nr 3, 5112-5135 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A multitude of wireless sensor devices and technologies are being developed and deployed in cities all over the world. Sensor applications in city environments may include highly mobile installations that span large areas which necessitates sensor mobility support. This paper presents and validates two mechanisms for supporting sensor mobility between different administrative domains. Firstly, EAP-Swift, an Extensible Authentication Protocol (EAP)-based sensor authentication protocol is proposed that enables light-weight sensor authentication and key generation. Secondly, a mechanism for handoffs between wireless sensor gateways is proposed. We validate both mechanisms in a real-life study that was conducted in a smart city environment with several fixed sensors and moving gateways. We conduct similar experiments in an industry-based anechoic Long Term Evolution (LTE) chamber with an ideal radio environment. Further, we validate our results collected from the smart city environment against the results produced under ideal conditions to establish best and real-life case scenarios. Our results clearly validate that our proposed mechanisms can facilitate efficient sensor authentication and handoffs while sensors are roaming in a smart city environment.

  • 12.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A Mobile Cloud Computing System for Emergency Management2014Ingår i: I E E E Cloud Computing, ISSN 2325-6095, Vol. 1, nr 4, 30-38 s., 7057583Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emergency management systems deal with the dynamic processing of data, where response teams must continuously adapt to the changing conditions at the scene of the emergency. Response teams must make critical decisions in highly demanding situations using large volumes of sensor data. Mobile devices have limited processing, storage, and battery resources; therefore, the sensed data from the scene of the emergency must be transmitted and processed quickly using the best available networks and clouds. Mobile cloud computing (MCC) is expected to play a critical role in the computation and storage offloading of sensor data to the best available clouds. However, applications running on mobile devices using clouds and heterogeneous access networks such as Wi-Fi and 3G are prone to unpredictable cloud workloads, network congestion, and handoffs. This article presents M2C2, a system for mobility management in MCC, that supports mechanisms for multihoming, cloud and network probing, and cloud and network selection. Through a prototype implementation and experiments, the authors show that M2C2 supports mobility efficiently in MCC scenarios such as emergency management.

  • 13.
    Tanaka, Rie
    et al.
    C and C Innovation Initiative, NEC Corporation.
    Schmidt, Mischa
    NEC Laboratories Europe, NEC Europe Ltd., Heidelberg.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Takamutsu, Yuri
    NEC Scandinavia.
    An energy awareness study in a Smart City lessons learned2014Ingår i: IEEE ISSNIP 2014: 2014 IEEE 9th International Conference on Intelligent Sensors, Sensor Networks and Information Processing, Conference Proceedings, Piscataway, NJ: IEEE Communications Society, 2014, 4- s., 6827663Konferensbidrag (Refereegranskat)
    Abstract [en]

    The SmartCity concept is becoming widely accepted and describes the usage of ICT for increased quality of life and also for a sustainable usage of natural resources. This paper describes a system architecture for monitoring of electrical energy consumption, and visualization of usage patterns to raise users' awareness of their energy usage which we field trialled over several months. The information collected of each household includes kWh, emission of carbon dioxide emissions and it also relates a household's consumption to other households attending the trial. Our results indicate that a fraction of the participants was interested in a detailed comparison with others whereas other participants had their main interest in not performing worse than the average household. Further, a large fraction had a demand for knowing the total energy usage of their household through an easily accessible visualization. These results indicate that there is support to embed sensing and feedback services to daily life for involving the residents of a SmartCity more.

  • 14.
    Idowu, Samuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Saguna, Saguna
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Forecasting Heat Load for Smart District Heating Systems: A Machine Learning Approach2014Ingår i: 2014 IEEE International Conference on Smart Grid Communications (SmartGridComm 2014): Venice, 3-6 Nov. 2014, Piscataway, NJ: IEEE Communications Society, 2014, 554-559 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The rapid increase in energy demand requires effective measures to plan and optimize resources for efficient energy production within a smart grid environment. This paper presents a data driven approach to forecasting heat load for multi- family apartment buildings in a District Heating System (DHS). The forecasting model is built using six and eleven weeks of data from five building substations. The external factors and internal factors influencing the heat load in substations are parameters used as our model’s input. Short-term forecast models are generated using four supervised Machine Learning (ML) techniques: Support Vector Regression (SVR), Regression Tree, Feed Forwards Neural Network (FFNN) and Multiple Linear Regression (MLR). Performance comparison among these ML methods was carried out. The effects of combining the internal and external factors influencing heat load at substations was studied. The models are evaluated with varying horizon up to 24-hours ahead. The results show that SVR has the best accuracy of 5.6% MAPE for the best-case scenario.

  • 15.
    Idowu, Samuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Machine learning in district heating system energy optimization2014Ingår i: 2014 IEEE International Conference on Pervasive Computing and Communications workshops: PERCOM WORKSHOPS 2014, Budapest, Hungary; 24-28 March 2014, Piscataway, NJ: IEEE Communications Society, 2014, 224-227 s., 6815206Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper introduces a work in progress, where we intend to investigate the application of Reinforcement Learning (RL) and online Supervised Learning (SL) to achieve energy optimization in District-Heating (DH) systems. We believe RL is an ideal approach since this task falls under the control-optimization problem where RL has yielded optimal results in previous work. The magnitude and scale of a DH system complexity incurs the curse of dimensionalities and model, hereby making RL a good choice since it provides a solution for the problem. To assist RL even further with the curse of dimensionalities, we intend to investigate the use of SL to reduce the state space. To achieve this, we shall use historical data to generate a heat load sub-model for each home. We believe using the output of these sub-models as feedback to the RL algorithm could significantly reduce the complexity of the learning task. Also, it could reduce convergence time for the RL algorithm. The desired goal is to achieve a realtime application, which takes operational actions when it receives new direct feedback. However, considering the dynamics of DH system such as large time delay and dissipation in DH network due to various factors, we hope to investigate things such as the appropriate data sampling rate and new parameters / sensors that could improve knowledge about the state of the system, especially on the consumer side of the DH network.

  • 16.
    Schelén, Olov
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A sensor-data acquisition grid architecture2013Ingår i: 2013 IEEE International Conference on Networking, Sensing and Control, Piscataway, NJ: IEEE Communications Society, 2013, 361-366 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents SAGA, a functional software architecture for distributing sensor data. The recursive architecture is dynamically instantiated for collecting, composing and storing data at multiple locations. Objectives are to support devices that are intermittently connected over different access-technologies, to save energy by avoiding repetitive transmission from sensors, and to scale out data compositions for different application services. When the architecture is instantiated the entities form a directed graph across organizational boundaries between sensors and applications. Data may be retrieved from sensors on-demand or be disseminated in real-time, for composition and delivery to the applications. The architecture is based on current sensor network principles such as client-server, representational state transfer and web services. The architecture is presented together with identified key requirements and design choices, and it has been instantiated in a prototype implementation for a smart city application. Some key issues for further research are presented.

  • 17.
    Idowu, Samuel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Schelén, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Machine Learning in Pervasive Computing2013Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Increase in data quantities and number of pervasive systems has resulted in many decision-making systems. Most of these systems employ Machine Learning (ML) in various practical scenarios and applications. Enormous amount of data generated by sensors can be useful in decision-making systems. The rising number of sensor driven pervasive systems presents interesting research areas on how to adapt and apply existing ML techniques effectively to the domain of pervasive computing. In the face of data deluge, ML has proved viable in many application areas such as data mining and self-customizing programs and could bring about great impact in the field of pervasive computing.The objective of this study is to give the underlying concepts of ML techniques that can be applied to problems in the domain of pervasive and mobile computing. The scope of this study covers the three primary types of ML, supervised, unsupervised and reinforcement learning methods. In the process of providing the fundamental knowledge of ML, we present some conceptual terms of ML and the steps required in developing ML system with a great impact on domains outside ML scope.Our findings show that previous works in the area of ubiquitous computing have successfully applied supervised learning and reinforcement learning methods. Hence, this study focuses more on supervised learning and reinforcement learning. In conclusion, we discuss some basic performance evaluation metrics and methods for obtaining reliable classifiers estimates, such as cross-validation and leave-one-out validation.

  • 18.
    Johansson, Dan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap. Luleå tekniska universitet, Institutionen för system- och rymdteknik, CDT.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Supporting user mobility with peer-to-peer-based application mobility in heterogeneous networks2013Ingår i: Proceedings of the 38th IEEE Conference on Local Computer Networks Workshops (LCN Workshops): 7th IEEE Workshop On User MObility and VEhicular Networks / [ed] Damla Turgut; Nils Aschenbruck; Jens Tölle, Piscataway, NJ, 2013, 150-153 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    When migrating applications between devices during runtime, one has achieved application mobility. In this paper we present the XAM system, providing application mobility through a peer-to-peer based solution over heterogeneous networks. Our architecture takes into consideration established requirements of application mobility, being application identification and distribution; context-awareness and context quality; seamlessness; heterogeneity support; and usability. Our system differs from traditional systems as it provides application mobility in a decentralized manner over heterogeneous networks, using different communication technologies. Following the evaluation of our system, we also discuss major challenges and possibilities for the continuing evolution of application mobility systems.

  • 19.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Measuring quality of experience in pervasive systems using probabilistic context-aware approach2012Ingår i: Mobile and Ubiquitous Systems: Computing, Networking, and Services: 7th International ICST Conference, MobiQuitous 2010, Sydney, Australia, December 6-9, 2010, Revised Selected Papers, Heidelberg: Encyclopedia of Global Archaeology/Springer Verlag, 2012, 330-331 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we pioneer a context-aware approach for quality of experience (QoE) modeling, reasoning and inferencing in mobile and pervasive computing environments. The proposed model is based upon Context Spaces Theory (CST) and influence diagrams (IDs) to handle uncertain and hidden complex inter-dependencies between user-perceived and network level QoS and to calculate overall QoE of the users. This helps in user-related media, network and device adaptation, creating user-level SLAs and minimizing network churn. We perform experimentation to validate the proposed approach and the results verify its modeling and inferencing capabilities.

  • 20.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Performance evaluation of a decision-theoretic approach for quality of experience measurement in mobile and pervasive computing scenarios2012Ingår i: 2012 IEEE Wireless Communications and Networking Conference (WCNC), Piscataway, NJ: IEEE Communications Society, 2012, 2418-2423 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Measuring and predicting users quality of experience (QoE) in dynamic network conditions is a challenging task. This paper presents results related to a decision-theoretic methodology incorporating Bayesian networks (BNs) and utility theory for quality of experience (QoE) measurement and prediction in mobile computing scenarios. In particular, we show how both generative and discriminative BNs can be used to measure and predict users QoE accurately for voice applications under several wireless network conditions such as wireless signal fading, vertical handoffs, wireless network congestion and normal hotspot traffic. Through extensive simulation studies and results analysis, we show that our proposed methodology can achieve an average accuracy of 98.70% using three different types of Bayesian network.

  • 21.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    QoE estimation and prediction using hidden Markov models in heterogeneous access networks2012Ingår i: 2012 Australasian Telecommunication Networks and Applications Conference: (ATNAC 2012) : Brisbane 7 November - 9 November 2012, Piscataway, NJ: IEEE Communications Society, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Quality of Experience (QoE) based handoffs inheterogeneous access networks (HAN) necessitates accurate QoEestimation and prediction. The current approaches to QoE-awarehandoffs are limited. These approaches either lack the availabilityof underlying probing mechanism or lack the availability ofQoE estimation and prediction mechanism. In this paper, wepropose, develop and validate a novel method for QoE estimationand prediction using passive probing mechanisms. Ourmethod is based on hidden Markov models and multi-homedmobility management protocol. Using extensive simulations andexperimental studies, we show that our method achieves QoEestimation accuracy of 100% and prediction accuracy of 97% inHAN without using additional probe packets for QoE estimationand prediction.

  • 22.
    Wallin, Stefan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Rethinking network management: models, data-mining and self-learning2012Ingår i: Proceedings of the 2012 IEEE Network Operations and Management Symposium: Maui, HI 16- 20 April 2012, Piscataway, NJ: IEEE Communications Society, 2012, 880-886 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Network Service Providers are struggling to re- duce cost and still improve customer satisfaction. We have looked at three underlying challenges to achieve these goals; an overwhelming flow of low-quality alarms, understanding the structure and quality of the delivered services, and automation of service configuration. This thesis proposes solutions in these areas based on domain-specific languages, data-mining and self- learning. Most of the solutions have been validated based on data from a large service provider.We look at how domain-models can be used to capture explicit knowledge for alarms and services. In addition, we apply data- mining and self-learning techniques to capture tacit knowledge. The validation shows that models improve the quality of alarm and service models, and automatically render functions like root cause correlation, service and SLA status, as well as service configuration automation.The data-mining and self-learning solutions show that we can learn from available decisions made by experts and automatically assign alarm priorities.

  • 23.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A decision-theoretic approach for quality of experience measurement and prediction2011Ingår i: 2011 IEEE International Conference on Multimedia and Expo, (ICME 2011): Barcelona, Spain, 11 - 15 July 2011 / [ed] Irene Cheng, Piscataway, NJ: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a pioneering context-aware approach for quality of experience (QoE) measurement and prediction. The proposed approach incorporates an intuitive context-aware framework and decision theory. It is capable of incorporating several QoE related classes and context information to correctly measure and predict the overall QoE on a single scale. Our approach can be used in measuring and predicting QoE in both lab and living-lab settings based on user, device and network related context parameters. The predicted QoE can be beneficial for network operators to minimize network churn and can help application developers to build smart user-centric applications. We perform extensive experimentation and the results validate our approach.

  • 24.
    Johansson, Dan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Andreas
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A MIP-P2P based architecture for application mobility2011Ingår i: Proceedings of the 10th International Conference on Mobile and Ubiquitous Multimedia: MUM '11, New York: ACM Digital Library, 2011, 85-93 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobility exists in many shapes; when migrating a running application (code, states and data) from one device to another, one has achieved application mobility. In this article we combine this mobility type with context awareness, defiining context awareness supported application mobility (CASAM) as when using context in the act of moving an application between hosts during its execution, to provide relevant information and/or services, where relevancy depends on the user's task. We identify and present five CASAM challenges, that are used to create requirements for a CASAM architecture. A proposal for an architecture, building on peer-to-peer (P2P) technology in combination with mobile IP, is then presented, addressing the identified challenges, providing a decentralized framework for global application mobility. As such, our architecture differs from earlier centralized and/or locally bound solutions for application mobility.

  • 25.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A probabilistic context-aware approach for quality of experience measurement in pervasive systems2011Ingår i: Proceedings of the 26th Annual ACM Symposium on Applied Computing 2011: Taichung, Taiwan, March 21 - 24, 2011, New York: ACM Digital Library, 2011, 419-424 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we develop a novel context-aware approach for quality of experience (QoE) modeling, reasoning and inferencing in mobile and pervasive computing environments. The proposed model is based upon a state-space approach and Bayesian networks for QoE modeling and reasoning. We further extend this context model to incorporate influence diagrams for efficient QoE inferencing. Our approach accommodates user, device and quality of service (QoS) related context parameters to determine the overall QoE of the user. This helps in user-related media, network and device adaptation. We perform experimentation to validate the proposed approach and the results verify its modeling and inferencing capabilities.

  • 26.
    Granlund, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A scalability study of AAA support in heterogeneous networking environments with global roaming support2011Ingår i: TrustCom 2011: 2011 international joint conference of IEEE TrustCom-11, IEEE ICESS-11 / FCST-11 : 16-19 November 2011, Changsha, Hunan, P. R. China / [ed] Guojun Wang, Los Alamitos, Calif: IEEE Computer Society Press , 2011, 488-493 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a scalability study of AAA support in mobile heterogeneous access networks with respect to server and network load related to AAA processes using the RADIUS protocol. Technologies such as IEEE 802.11, CDMA 2000 and UMTS which all support the RADIUS protocol for AAA handling are discussed and analyzed. Typical performance data are gathered and complemented with a theoretical study in order to achieve an overview of what parameters will affect the performance and scalability of the network. Also, guidelines are developed for network design in order to achieve the desired performance for a given number of users. Results of this study include the conclusion that the main bottleneck of the AAA procedure is not necessarily the AAA server CPU power. Aside the cases with a high proportion of computationally intensive WiFi sign-ons with strong encryption, performance issues may be caused by AAA server network connection bandwidth, and RAM memory. In cases where a high number of users reside in the same user database, database performance becomes a significant issue. In order to achieve better performance, CPU load balancing over several servers may be performed.

  • 27.
    Rahmani, Rahim
    et al.
    Mittuniversitetet.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Kanter, Theo
    Mittuniversitetet.
    Design of active queue management for robust control on access router for heterogeneous networks2011Ingår i: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2011, 946498Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Internet architecture is a packet switching technology that allows dynamic sharing of bandwidth among different flows with in an IP network. Packets are stored and forwarded from one node to the next until reaching their destination. Major issues in this integration is congestion control and how to meet different quality of service requirements associated with various services. In other words streaming media quality degrades with increased packet delay and jitter caused by network congestion. To mitigate the impact of network congestion various techniques have been used to improve multimedia quality and one of those techniques is Active Queue Management (AQM). Access routers require a buffer to hold packets during times of congestion. A large buffer can absorb the bursty arrivals and this tends to increase the link utilizations but results in higher queuing delays. Traffic burstiness has a considerable negative impact on network performance. AQM is now considered an effective congestion control mechanism for enhancing transport protocol performance over wireless links. In order to have good link utilization it is necessary for queues to adapt to varying traffic loads. This paper considers a particular scheme which is called Adaptive AQM (AAQM) and studies its performance in the presence of feedback delays and its ability to maintain a small queue length as well as its robustness in the presence of traffic burstiness. The paper also presents a method based on the well-known Markov Modulated Poisson Process (MPP) to capture traffic burstiness and buffer occupancy. To demonstrate the generality of the presented method an analytic model is described and verified by extensive simulations of different adaptive AQM algorithms. The analysis and simulations show that AAQM outperforms the other AQMs with respect to responsiveness and robustness.

  • 28.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Dynamic Bayesian networks for sequential quality of experience modelling and measurement2011Ingår i: Smart Spaces and Next Generation Wired/Wireless Networking: 11th International Conference, NEW2AN 2011, and 4th Conference on Smart Spaces, ruSMART 2011, St. Petersburg, Russia, August 22-25, 2011. Proceedings / [ed] Sergey Balandin; Yevgeni Koucheryavy; Honglin Hu, Encyclopedia of Global Archaeology/Springer Verlag, 2011, 135-146 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a novel context-aware methodology for modelling and measuring user-perceived quality of experience (QoE) over time. In particular, we create a context-aware model for QoE modelling and measurement using dynamic Bayesian networks (DBN) and a context-aware state-space approach. The proposed model is then used to infer and determine users’ QoE in a sequential manner. We performed experimentation to validate the proposed model. The results prove thatit can efficiently model, reason and measure QoE of the users’.

  • 29.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Optimized access network selection in a combined WLAN/LTE environment2011Ingår i: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 61, nr 4, 739-751 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multimode terminals equipped with multiple radio access technologies are becoming increasingly popular. At the same time, network operators and service providers seek opportunities to deliver seamless services cost effectively, leveraging a variety of radio access technologies using both licensed and unlicensed spectrum. In order to standardize the operations of such complex environments 3GPP is currently working on IP flow mobility and mobile data offload solutions. This article proposes and evaluates a new access network selection procedure in such a combined WLAN/LTE environment. The proposed solution takes not only parameters available in the mobile node and its current and candidate access networks into account, but performs an optimization on the heterogeneous wireless network level as well. An optimization model based on an approximate solution to the well-known bin packing problem is presented. Also, there is a signaling scheme for distribution handling presented. Results from simulations performed in OPNET Modeler show improvements compared to basing handover decisions on locally available information only.

  • 30.
    Cherkaoui, S.
    et al.
    Sherbrooke University.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Welcome message from the ON-MOVE 2010 co-chairs2011Övrigt (Övrigt vetenskapligt)
  • 31.
    Rahmani, R.
    et al.
    Department of Information Technology and Media, Mid-Sweden University.
    Kanter, T.
    Department of Information Technology and Media, Mid-Sweden University.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A self configuring fuzzy active queue management controller in heterogeneous networks2010Ingår i: ICT 2010: 2010 17th International Conference on Telecommunications, Piscataway, NJ: IEEE Communications Society, 2010, 634-641 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    To achieve self configuring of Active Queue Management based on Fuzzy Logic Controller (FLC), we propose a Fuzzy Adaptive Active Queue Management Controller (FAAQMC). FAAQMC eliminates buffer overflow by adapting the buffer size to the required queue length with a control cycle time shorter than the mean inter-arrival time of a burst. This makes FAAQMC suitable to manage invariant burstiness or self-similar network traffic.

  • 32.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Granlund, Daniel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Elkotob, Muslim
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Bandwidth efficient mobility management for heterogeneous wireless networks2010Ingår i: 2010 7th IEEE Consumer Communications and Networking Conference: Las Vegas, Nevada, USA : 9-12 January, 2010, Piscataway, N.J: IEEE Communications Society, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    An important feature of the upcoming fourth generation wireless networks is support for heterogeneous radio access technologies in combination with an all-IP type of overall architecture. Operators and users will benefit from a smooth technology transition leveraging existing investments and use a variety of access technologies simultaneously. This paper describes and evaluates an innovative mobility management scheme in such an environment. It does not require any changes to the IP stack in the mobile node and does not introduce any additional overhead to the payload traffic over air interfaces. Furthermore, it does not add any signaling overhead and outperforms existing mobility management schemes for heterogeneous environments in terms of bandwidth consumption. The architecture uses a make-before-break principle for vertical handovers and bidirectional tunneling using various tunneling mechanisms connecting mobile nodes through access networks to a home network. Also, it proposes a packet inspection routine for timely handover execution in the home network. The architecture is evaluated both through analytical calculations and experiments using a voice over IP traffic model.

  • 33.
    Rahmani, R.
    et al.
    Mittuniversitetet.
    Kanter, T.
    Mittuniversitetet.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Fuzzy set-based analysis and design of AQM controller for access router in heterogeneous networks2010Ingår i: 2nd International Conference on Computational Intelligence, Communication Systems and Networks, CICSyN 2010: Liverpool; 28 July 2010 through 30 July 2010, Piscataway, NJ: IEEE Communications Society, 2010, 173-181 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose a Fuzzy Adaptive Active Queue Management Controller (FAAQMC). Its performance objectives are efficient queue utilization, regulated queuing delay, and robustness. In order to achieve efficient queue utilization, the FAAQMC controls buffer length loading of both time-varying arrival rate and departure rate. The FAAQMC regulates queuing delay by minimize buffering with small queue lengths. In order to achieve robustness the FAAQMC maintains both resource provisioning and dimensioning performance under varying network conditions including variations in the number of flows, variation in Round Trip Time (RTT), and link capacity. The FAAQMC does so by using a Transformation method with fuzzy sets as numerical representation of uncertain network parameters.

  • 34.
    Elkotob, Muslim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Granlund, Daniel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Multimedia QoE optimized management using prediction and statistical learning2010Ingår i: 35th Annual IEEE Conference on Local Computer Networks: LCN 2010, Piscataway, NJ: IEEE Communications Society, 2010, 328-331 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a scheme for flow management with heterogeneous access technologies available indoors and in a campus network such as 3G and Wi-Fi. Statistical learning is used as a key for optimizing a target variable namely video quality of experience (QoE). First we analyze the data using passive measurements to determine relationships between parameters and their impact on the main performance indicator, namely the video QoE value. The derived weights are used for performing prediction in every discrete time interval of our designed autonomic control loop to know approximately the QoE in the next time interval and be able to perform a switch to another access technology if it yields a better QoE level. This user-perspective performance optimization is in line with operator and service provider goals. QoE performance models for slow vehicular and pedestrian speeds for Wi-Fi and 3G are derived and compared as well.

  • 35.
    Åhlund, Christer
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Börjesson, Mikael
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Pettersson, Jan
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Larsson, Roger
    Johansson, Dan
    Granlund, Daniel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Project: Sense Smart City2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Sense Smart City is a Swedish project designed to conduct research, create new business opportunities and sustainably increase ICT research and innovation capability with specific objective to make urban cities/areas "smarter". The project will generate new and better ICT solutions, that instrument urban areas to gather and combine information (energy, traffic, weather, events, activities, needs and oppinions) continously as well as "on-demand". This will enable city environments to become "smarter", as more adaptive and supportive environment, for its inhabitants and visitors - people as well as organisations.

  • 36.
    Mitra, Karan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    PRONET: proactive context-aware support for mobility in heterogenous access networks2010Ingår i: 2009 IEEE 34th Conference on Local Computer Networks: LCN 2009 ; Zurich, Switzerland, 20 - 23 October 2009, Piscataway, NJ: IEEE Communications Society, 2010, 675-676 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a blueprint for proactive context-aware mobility support architecture for heterogeneous access networks called PROET. In particular, we leverage upon the principles of cognitive networking to support proactive contextawareness for user-centric application adaptation via quality-ofexperience (QoE) provisioning. Our proposed architecture is built upon Port-based Multi-homed Mobile IPv6 (PM-MIPv6) solution to support several applications via path diversity. In this paper our contributions are two-fold. Firstly, we identify and present gaps in our research domain related to mobility, QoE, cognitive networks and cross-layer design. We then present our architecture for providing seamless mobility in heterogeneous access networks. Currently, we are in the process of collecting results via our test bed and prototype implementation for 802.11g and HSDPA wireless networks

  • 37.
    Granlund, Daniel
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Elkotob, Muslim
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A uniform AAA handling scheme for heterogeneous networking environments2009Ingår i: 2009 IEEE 34th Conference on Local Computer Networks: LCN 2009 ; Zurich, Switzerland, 20 - 23 October 2009 ;, Piscataway, NJ: IEEE Communications Society, 2009, 683-687 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Starting with an efficient mobility management scheme for heterogeneous wireless networks, this paper proposes a solution for AAA handling using a common database for storing user information. Regardless of the access technology selected, user@realm identities are used for authentication, authorization, and accounting. In particular, a new function is introduced in which port-based network access control is used in combination with dynamic host configuration protocol mechanisms for IP address allocation. This way, PPP-based and Ethernet-based access technologies are handled uniformly.Advantages with the proposed solution include: using only standardized mechanisms in the mobile node, as well as in the access networks. Only an additional plug-in in the AAA server (located in the access networks) needs to be deployed.The proposed AAA architecture has been implemented and evaluated in a live experimental environment. Results show authentication and authorization to perform efficiently and seamlessly.

  • 38.
    Kodikara, Ruwini
    et al.
    Monash University, Melbourne, VIC.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Context modelling for crosslayer context aware adaptations2009Ingår i: International Journal On Advances in Networks and Services, ISSN 1942-2644, E-ISSN 1942-2644, Vol. 2, nr 1, 63-75 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Demand for real-time services over the Internet while moving, is growing rapidly. This necessitates efficient delivery of wireless real-time traffic. Limitations of existing layered protocol stack for wireless networks lead to the proposal of cross-layer interactions as an alternative solution. At the same time, next generation ubiquitous computing drives wireless applications and protocols to be context aware. A generic context aware architecture with context modeling can aid increasingly demanding realtime applications over highly dynamic wireless networks to be cross-layer context aware and adaptive. Moreover, a generic architecture can make lower layer protocols to be context aware and adaptive to various situations dynamically. This article discusses the adaptive approach supported by proposed cross layer context aware architecture called CA3RM-Com. The scope of this article is to discuss context modeling specifically and address the issue of context representation of multi-layer context for various adaptive situations. Various single layer and multi-layer crosslayer adaptations and the representation of context parameters with respect to each layer of the protocol stack is discussed. We discuss how these adaptations can be operated in the proposed CA3RM-Com architecture. Context aware adaptive multi-homed Mobile IP is discussed as an example adaptation that the architecture can support. Moreover, the extended simulation of context aware adaptive multi-homed Mobile IP is discussed.

  • 39.
    Åhlund, Andreas
    et al.
    Umeå University, Department of Computer Science.
    Mitra, Karan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Johansson, Dan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Context-aware application mobility support in pervasive computing environments2009Ingår i: Proceedings of the 6th International Conference on Mobile Technology, Application & Systems : 2009, Nice, France, September 02 - 04, 2009, New York: ACM Digital Library, 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the future, application mobility can play a crucial role and prove to be an enabler for next generation distributed applications. Application mobility lets an application follow the users while they roam between networks using several devices. In order to achieve seamless application mobility, several issues need to be considered such as device heterogeneity, GUI-adaptation and application loss. Thus, in this paper our contributions are two-fold. Firstly, we present our novel architecture called the Application Mobility Manager (A2M) which provides seamless application mobility. The proposed architecture is context-aware and decentralized. Finally, we present a novel application called the Mobile YouTube Player which is capable of moving between heterogeneous devices and provide users with seamless video experience. We validate the proposed system through rigorous experimentation and user studies based on the real-world test bed and prototype implementation. The results clearly validate that the proposed system can support seamless application mobility.

  • 40.
    Rahmani, Rahim
    et al.
    Department of Information Technology and Media, Mid-Sweden University, Sundsvall.
    Kanter, Theo
    Department of Information Technology and Media, Mid-Sweden University, Sundsvall.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Fuzzy control of active queue management for bursty traffic in heterogeneous networks2009Ingår i: IEEE 9th Malaysia International Conference on Communications: MICC 2009 ; Kuala Lumpur, Malaysia, 15 - 17 December 2009 / [ed] Mahamod Ismail, Piscataway, NJ: IEEE Communications Society, 2009, 491-496 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose Fuzzy Adaptive Active Queue Management Controller (FAAQMC) for dynamic buffer tuning at the router/system-level. The intention of an AQM is to achieve high link utilization without introducing an excessive delay in the End-to-End (E2E) path. For high link utilization it is necessary for queues to adapt to varying traffic loads. The contribution of FAAQMC is to make the Fuzzy Logic Controller (FLC) buffer overflow controller suitable for application over the Internet, where the traffic(i.e., bursty traffic) can change suddenly and the buffer length always cover the queue length adaptively. The desire to eliminate the overestimation effect of standard fuzzy arithmetic in the case of Internet traffic burstiness and preserve the FAAQMC merits the use of this adaptation and learning mechanism

  • 41.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Mobile mediator control function: an IEEE 802.21-based mobility management and access network selection model2009Ingår i: Proceedings of the 18th ICT-Mobile Summit / [ed] Paul Cunningham; Miriam Cunningham, IIMC International Information Management Corporation , 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes a combined network and application layer access network decision model for multimedia applications in heterogeneous networking environments. It builds on previous work of a network layer based metric used in combination with multihomed Mobile IP and introduces a mechanism for applications to interact with the mobility management system in the mobile node. This way, applications executing in the mobile node can decide either to take access network decisions on their own or to let the network layer handle mobility management tasks automatically based on default decision criterion decided by the end-user.An extended architecture based on previous work and the upcoming IEEE 802.21 standard for media-independent handover services is presented. The control plane, named "Mobile Mediator Control Function", offers a set of events and commands through an additional service access point. Results from a scenario with a Voice over IP application running in the proposed environment simulated in OPNET Modeler are presented.

  • 42. Johansson, Dan
    et al.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Andersson, Karl
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Projekt: MOSA - mobil och öppen tjänste-access2009Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Projektet ämnar till att möjliggöra uppkoppling av fler hushåll och företag till bredbandsnät, utveckla en teknisk plattform som ökar tillgång till tjänster och möjliggör mobilitet mellan olika accessnätverk. Genom att möjliggöra mobilitet kommer tjänster att vara nåbara på flera platser, mobiliteten skapar också utrymme för nya tjänster.

  • 43.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A mobility management scheme for heterogeneous environments supporting vehicular speeds using a policy-based approach2008Ingår i: Proceedings of the 5th International Workshop Conference on Performance Modelling and Evaluation of Heterogeneous Networks: (HET-NETs), 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today, handsets and terminals are typically equipped with multiple radio interfaces. Meanwhile, various types of access networks using different radio technologies are being deployed all over the world. Also, there is a strong trend towards All-IP-Networks following the principle "Everything over IP", and "IP over everything". This development is leading researchers into the area of heterogeneous networking and overlay topologies.This paper focuses on mobility management issues related to such an environment supporting vehicular speeds of users using a policy-based approach and a network-layer metric for access network selection.A Mobile IP-based architecture is proposed where mobility bindings are sent periodically at a frequency depending on the speed of the user also taking variations in the network-layer metric into account and the overall signaling cost. The architecture is designed with a focus on minimizing packet losses and timely handling of vertical hand-overs.

  • 44.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Elkotob, Muslim
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A new MIP-SIP interworking scheme2008Ingår i: MUM'08 Proceedings: 7th ACM International Conference on Mobile and Ubiquitous Multimedia, December 3 - 5, 2008, Umeå, Sweden, New York: ACM Digital Library, 2008, 117-120 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mobility management is today handled at various layers in the network stack including the datalink layer, the network layer, the transport layer and the application layer. Also, cross-layer designed solutions exist and the most known example is the work performed by IEEE currently standardizing media-independent handover services under the name of IEEE 802.21.This paper proposes a new interworking scheme for Mobile IP and the Session Initiation Protocol being the most popular solutions for mobility management at the network and application layers respectively. The goal is to deliver seamless mobility for both TCP-based and UDP-based applications taking the best features from each mobility management scheme. In short, this paper proposes that TCP connections are handled through Mobile IP while UDP-based connection-less applications may use the Session Initiation Protocol for handling mobility. The two mobility management solutions are integrated into one common solution.

  • 45.
    Åhlund, Christer
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Wallin, Stefan
    Andersson, Karl
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    A service level model and Internet mobility monitor2008Ingår i: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 37, nr 1-3, 49-70 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mobility is gaining a tremendous interest among Internet users and wireless access networks are increasingly being installed to enable mobile usage. Internet mobility requires solutions to move between access networks with maintained network connectivity. Seamless mobility in turn means that the experience of using a service is unaffected while being mobile. Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. Further, roaming between network service providers may take place. To enable mobile nodes to move between access networks within as well as between network service providers with minimal disruption, nodes should be able to maintain multiple active network connections. With the usage of multihomed nodes, seamless mobility can be achieved in already installed infrastructures, not providing mobility support. Mobility in heterogeneous access networks also requires network selections that scale for services. In this article we propose an architecture where application service providers and network service providers define service levels to be used by a mobile node and its user. The user selects a service and the service level from an application service provider. When performing access network selection, information received as part of an application service level will be used to find a network that supports the service required. The performance of available access networks will be monitored and considered when making the decision. Our proposed architecture provides solutions to move flows between interfaces in real-time based on network performance, quality of service signalling to correspondent nodes, and cancellation of flows to give way for more important traffic.

  • 46.
    Rahmani, Rahim
    et al.
    Mittuniversitetet, Sundsvall.
    Hjelm, Mats
    Mittuniversitetet, Sundsvall.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Active queue management for TCP friendly rate control traffic in heterogeneous networks2008Ingår i: International Conference on Telecommunications: ICT 2008, Piscataway, NJ: IEEE Communications Society, 2008, 1-7 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the increasing number of media flows using UDP in IP networks there is a strong need to enable fairness between UDP and TCP traffic. The TCP traffic will suffer because of the unresponsiveness of UDP to congestion in the IP network. To enable responsiveness of UDP traffic, the TCP-Friendly Rate Control (TFRC) protocol can be used. With the coexistence of TCP and UDP, where the rate adaptation of UDP is managed by the TFRC protocol, knowledge is needed about how Active Queue Management (AQM) algorithms perform to optimize networks performance. This paper studies the behavior of several AQM algorithms when small packet UDP flows compete with TCP flows in a heterogeneous network. A simulation study is presented, showing the results of different AQM algorithms. It shows that the Adaptive AQM (AAQM) is very promising with respect to responsiveness and robustness.

  • 47.
    Andersson, Karl
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Åhlund, Christer
    Gukhool, Balkrishna Sharma
    Electrical and Computer Engineering Department, Sherbrooke University.
    Cherkaoui, Soumaya
    Electrical and Computer Engineering Department, Sherbrooke University.
    Mobility management for highly mobile users and vehicular networks in heterogeneous environments2008Ingår i: 2008 IEEE 33rd Conference on Local Computer Networks: [LCN 2008] ; Montreal, AB, Canada, 14 - 17 October 2008, Piscataway, NJ: IEEE Communications Society, 2008, 593-599 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the recent developments in wireless networks, different radio access technologies are used in different places depending on capacity in terms of throughput, cell size, scalability etc. In this context, mobile users, and in particular highly mobile users and vehicular networks, will see an increasing number and variety of wireless access points enabling Internet connectivity. Such a heterogeneous networking environment needs, however, an efficient mobility management scheme offering the best connection continuously. In this paper, a mobility management architecture focusing on efficient network selection and timely handling of vertical and horizontal hand-overs is proposed. The solution is based on Mobile IP where hand-over decisions are taken based upon calculations of a metric combining delay and delay jitter. For efficiency reasons, the frequency of binding updates is dynamically controlled, depending on speed and variations in the metric. The dynamic frequency of binding updates helps the timely discovery of congested access points and cell edges so as to allow efficient hand-overs that minimize packet drops and hand-over delays.Results show that the overall signaling cost is decreased and changes in networking conditions are detected earlier compared to standard Mobile IP.

  • 48. Granlund, Daniel
    et al.
    Gylling, Arne
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, CDT.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Osipov, Evgeny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Brännström, Robert
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Jacquier, Anna
    Elkotob, Muslim
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, CDT.
    Åhl, Anneli
    Project: BASICNET2008Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Broadband Access Services In Converging NETworks

  • 49.
    Kodikara, Ruwini
    et al.
    Centre for Distributed Systems and Software Engineering, Monash University.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Supporting adaptive real-time mobile communication with multilayer context awareness2008Ingår i: Wireless and Mobile Networking: IFIP Joint Conference on Mobile and Wireless Communications Networks (MWCN'2008) and Personal Wireless Communications (PWC'2008), Toulouse, France, September 30 - October 2, 2008 / [ed] Zoubir Mammeri, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2008, 435-446 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Real time mobile communication is challenging due to the inherent limitations of mobile networks. On the other hand the stringent quality of service requirements of real time traffic is highly in demand. Our first contribution is the generic context aware architecture for adaptive real time applications. Adaptation is based on the awareness of context parameters from different layers of the existing protocol stack which involves context exchange among the neighboring layers as well as non-neighboring layers. The architecture comprises of context representation, context acquisition, cross-layer context exchange and context management. Our second contribution is the mobility aware, adaptive Multi-homed Mobile IP. Simulation of adaptive M-MIP was carried out as a proof of concept. Simulation demonstrated that adaptation to mobility was able to decrease Mobile IP handover latency. Further, the results show that the quality of service of real time traffic can be enhanced by using context aware adaptive MIP. The simulation involved with various speeds ranging from pedestrian scenarios to vehicular scenarios. Results are analyzed with variable data rates. The evaluations show that performance of the proposed solution is better compared to conventional MIP in terms of packet loss and throughput of real time traffic.

  • 50.
    Kodikara, Ruwini E.
    et al.
    Centre for Distributed Systems and Software Engineering, Monash University.
    Åhlund, Christer
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Zaslavsky, Arkady
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Towards context aware adaptation in wireless networks2008Ingår i: Proceedings: The Second International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies, UBICOMM 2008 : 29 September - 4 October 2008, Valencia, Spain / [ed] Jaime Lloret Mauri, Piscataway, NJ: IEEE Communications Society, 2008, 245-250 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Next generation ubiquitous computing will comprise of context aware adaptive applications and protocols. There is a need of a generic architecture to cater for the adaptation requirements of increasingly demanding real-time applications and increasing dynamic wireless networks. This paper discusses the adaptive approach supported by CA3RM-Com architecture. CA3RM-Com is the context aware architecture proposed for real-time communication in wireless networks. It addresses the context representation, context acquisition, context exchange,and context management. Specific details of the architecture and referring adaptations that CA3RM-Com can support are discussed. Moreover the extended simulation results of adaptive multi-homed Mobile IP are presented in this paper.

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