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Amirian P and Basiri A (2016), "Landmark-Based Pedestrian Navigation Using Augmented Reality and Machine Learning", In Prog. Cartogr.. , pp. 451-465. Springer International Publishing.
BibTeX:
    @incollection{amirian2016landmark,
      author = {Amirian, Pouria and Basiri, Anahid},
      title = {Landmark-Based Pedestrian Navigation Using Augmented Reality and Machine Learning},
      booktitle = {Prog. Cartogr.},
      publisher = {Springer International Publishing},
      year = {2016},
      pages = {451--465}
    }
    
Amirian P, Basiri A, Gales G, Winstanley A and McDonald J (2015), "The Next Generation of Navigational Services Using OpenStreetMap Data: The Integration of Augmented Reality and Graph Databases", In OpenStreetMap in GIScience. Cham , pp. 211-228. Springer International Publishing.
Abstract: The OpenStreetMap (OSM) project is the most successful collaborative geospatial content generation project. The distinguishing attribute of OSM is free access to huge amounts of geospatial data, which has resulted in hundreds of commercial and non-commercial web and mobile applications and services. The OSM data is freely available and that is why the data can be used within many data infrastructure applications and value-added services. In addition, the free access to data has led to the growth of OSM as a replacement of propriety systems in academic and business environments. This chapter describes the implementation of a navigational application using OSM data as part of the eCampus project in Maynooth University (formerly known as National University of Ireland Maynooth or NUIM). The application provides users several navigation services with navigational instructions through standard textual and cartographic interfaces and also through augmented images showing way-finding objects. There are many navigation services available over the internet; however, the navigation services in this chapter are implemented using a graph database which can be used in connected as well as disconnected modes (online and offline). In addition to the graph database, there is a spatial database for storage and management of images in the system. In other words, the implemented eCampus uses polyglot geospatial data persistence in order to get the best features of several storage systems in a single system in contrast to many traditional storage systems in which all data is stored in a single storage system. The evaluation of the eCampus application by the target users of university students and staff indicated that the visual navigation service using augmented reality provides an intuitive interface that could be integrated into augmented reality systems.
BibTeX:
    @incollection{JokarArsanjani2015,
      author = {Amirian, Pouria and Basiri, Anahid and Gales, Guillaume and Winstanley, Adam and McDonald, John},
      editor = {Jokar Arsanjani, Jamal and Zipf, Alexander and Mooney, Peter and Helbich, Marco},
      title = {The Next Generation of Navigational Services Using OpenStreetMap Data: The Integration of Augmented Reality and Graph Databases},
      booktitle = {OpenStreetMap in GIScience},
      publisher = {Springer International Publishing},
      year = {2015},
      pages = {211--228},
      doi = {10.1007/978-3-319-14280-7_11}
    }
    
Amirian P, Basiri A, Van Loggerenberg F, Moore T, Lang T and Varga M (2015), "Intersection of Geospatial Big Data, Geocomputation and Cloud Computing", In EuroCarto2015.
BibTeX:
    @inproceedings{amirian2015intersection,
      author = {Amirian, Pouria and Basiri, Anahid and Van Loggerenberg, Francois and Moore, Terry and Lang, Trudie and Varga, Margaret},
      title = {Intersection of Geospatial Big Data, Geocomputation and Cloud Computing},
      booktitle = {EuroCarto2015},
      year = {2015}
    }
    
Amirian P, Basiri A and Winstanley A (2014), "Evaluation of Data Management Systems for Geospatial Big Data", In Comput. Sci. Its Appl. – ICCSA 2014. Cham Vol. 8583, pp. 678-690. Springer International Publishing.
Abstract: Big Data encompasses collection, management, processing and analysis of the huge amount of data that varies in types and changes with high frequency. Often data component of Big Data has a positional component as an important part of it in various forms, such as postal address, Internet Protocol (IP) address and geographical location. If the positional components in Big Data extensively used in storage, retrieval, analysis, processing, visualization and knowledge discovery (geospatial Big Data) the Big Data systems need certain type of techniques and algorithms for management, analytics and sharing. This paper describes the concept of geospatial Big Data management with focus on using typical and modern database management systems. Then the typical and modern types of databases for management of geospatial Big Data are evaluated based on model for storage, query languages, handling connected data, distribution models and schema evolution. As the results of the evaluations and benchmarks of this paper illustrate there is no single solution for efficient management of geospatial Big Data and in order to utilize unique characteristics of geospatial Big Data (such as topological, directional and distance relationship) a polyglot geospatial data persistence system is needed.
BibTeX:
    @incollection{Murgante2014,
      author = {Amirian, Pouria and Basiri, Anahid and Winstanley, Adam},
      editor = {Murgante, Beniamino and Misra, Sanjay and Rocha, Ana Maria A. C. and Torre, Carmelo and Rocha, Jorge Gustavo and Falcão, Maria Irene and Taniar, David and Apduhan, Bernady O. and Gervasi, Osvaldo},
      title = {Evaluation of Data Management Systems for Geospatial Big Data},
      booktitle = {Comput. Sci. Its Appl. – ICCSA 2014},
      publisher = {Springer International Publishing},
      year = {2014},
      volume = {8583},
      pages = {678--690},
      doi = {10.1007/978-3-319-09156-3_47}
    }
    
Basiri A and Amirian P (2014), "Automatic Point of Interests Detection Using Spatio-Temporal Data Mining Techniques over Anonymous Trajectories", In Comput. Sci. Its Appl. ICCSA 2014. Guimarães, Portugal Vol. 8582, pp. 185-198. Springer International Publishing.
Abstract: Location Based Services (LBS) are evolving very fast but despite this are still at an early phase of their evolution. The future LBS services will be more anticipatory of users needs and will exploit a broader range of information on users. In order to anticipate users' needs, LBS providers should be able to understand users' behaviours, preferences and interests automatically and without asking the user to specify them. Then using the user's current situation and previously extracted behaviours, interests and dislikes, the user's needs can be predicted at the relevant moment and provide the most appropriate sets of services. This paper shows the application of data mining techniques over anonymous sets of tracking data to recognise mobility behaviours and preferences of users such as Point of Interest (PoI). Tracking data are first anonymised then stored in a spatio-temporal database. Then, using data mining techniques, rules, models and patterns are recognised. Such knowledge, patterns and models are subsequently used for intelligent navigation services as input making suggestions.
BibTeX:
    @incollection{Murgante2014b,
      author = {Basiri, Anahid and Amirian, Pouria},
      editor = {Murgante, Beniamino and Misra, Sanjay and Rocha, Ana Maria A. C. and Torre, Carmelo and Rocha, Jorge Gustavo and Falcão, Maria Irene and Taniar, David and Apduhan, Bernady O. and Gervasi, Osvaldo},
      title = {Automatic Point of Interests Detection Using Spatio-Temporal Data Mining Techniques over Anonymous Trajectories},
      booktitle = {Comput. Sci. Its Appl. ICCSA 2014},
      publisher = {Springer International Publishing},
      year = {2014},
      volume = {8582},
      pages = {185--198},
      doi = {10.1007/978-3-319-09147-1}
    }
    
Basiri A, Amirian P and Winstanley A (2014), "Use of Graph Databases in Tourist Navigation Application", In Comput. Sci. Its Appl. ICCSA. Guimarães, Portugal Vol. 8583, pp. 663-678. Springer International Publishing.
Abstract: Navigation services, such as car navigation services, are widely used nowadays. However current car navigation systems are not fully suitable for the navigational needs of tourists. In contrast with drivers, tourists are not constrained by road networks and can walk in places where vehicles are not allowed to move. As current turn-by-turn navigational instructions to be given to vehicle's derivers are mostly based on street network-based algorithms, this way of navigating is not fully suitable for tourists as they do not only move on streets. In addition, Tourists want to see important feature of the area, no matter they take longer path rather than shortest. They want to get navigated through the most touristic path. In order to provide such tourist-specific navigation services, a landmark-based solution was considered. it calculates a route passing more landmarks. This may help user to visit attractive part of a place. It is possible to provide users with the navigational instructions landmark-by-landmark rather than turn-by-turn. In this application, a graph database is used because of having highly connected data and also need to remove the mapping layer between physical storage layer and application logic layer to have more availability and responsiveness.
BibTeX:
    @incollection{Murgante2014c,
      author = {Basiri, Anahid and Amirian, Pouria and Winstanley, Adam},
      editor = {Murgante, Beniamino and Misra, Sanjay and Rocha, Ana Maria A. C. and Torre, Carmelo and Rocha, Jorge Gustavo and Falcão, Maria Irene and Taniar, David and Apduhan, Bernady O. and Gervasi, Osvaldo},
      title = {Use of Graph Databases in Tourist Navigation Application},
      booktitle = {Comput. Sci. Its Appl. ICCSA},
      publisher = {Springer International Publishing},
      year = {2014},
      volume = {8583},
      pages = {663--678},
      doi = {10.1007/978-3-319-09156-3}
    }
    
Basiri A, Amirian P and Winstanley A (2014), "The Use of Quick Response (QR) Codes in Landmark-Based Pedestrian Navigation", Int. J. Navig. Obs.. Vol. 2014(Article ID 897103), pp. 7 pages.
Abstract: Vehicle navigation systems usually simply function by calculating the shortest fastest route over a road network. In contrast, pedestrian navigation can have more diverse concerns. Pedestrians are not constrained to road/path networks; their route may involve going into buildings (where accurate satellite locational signals are not available) and they have different priorities, for example, preferring routes that are quieter or more sheltered from the weather. In addition, there are differences in how people are best directed: pedestrians noticing landmarks such as buildings, doors, and steps rather than junctions and sign posts. Landmarks exist both indoors and outdoors. A system has been developed that uses quick response (QR) codes affixed to registered landmarks allowing users to localise themselves with respect to their route and with navigational instructions given in terms of these landmarks. In addition, the system includes images of each landmark helping users to navigate visually in addition to through textual instructions and route maps. The system runs on a mobile device; the users use the device's camera to register each landmark's QR code and so update their position (particularly indoors) and progress through the route itinerary.
BibTeX:
    @article{Basiri2014b,
      author = {Basiri, Anahid and Amirian, Pouria and Winstanley, Adam},
      title = {The Use of Quick Response (QR) Codes in Landmark-Based Pedestrian Navigation},
      journal = {Int. J. Navig. Obs.},
      year = {2014},
      volume = {2014},
      number = {Article ID 897103},
      pages = {7 pages},
      url = {http://www.hindawi.com/journals/ijno/2014/897103/abs/},
      doi = {10.1155/2014/897103}
    }
    
Basiri A, Amirian P, Winstanley A, Marsh S, Moore T and Gales G (2016), "Seamless Pedestrian Positioning and Navigation Using Landmarks", J. Navig.., June, 2016. Vol. 69(1), pp. 24-40. Cambridge University Press.
BibTeX:
    @article{basiri2016seamless,
      author = {Basiri, Anahid and Amirian, Pouria and Winstanley, Adam and Marsh, Stuart and Moore, Terry and Gales, Guillaume},
      title = {Seamless Pedestrian Positioning and Navigation Using Landmarks},
      journal = {J. Navig.},
      publisher = {Cambridge University Press},
      year = {2016},
      volume = {69},
      number = {1},
      pages = {24--40},
      url = {http://journals.cambridge.org/abstractS0373463315000442}
    }
    
Basiri A, Amirian P, Winstanley A, Moore T and Hill C (2014), "Spatial Uncertainty Management in Pedestrian Navigation", In Princ. Appl. Prog. Locat. Serv.. , pp. 343-355. Springer International Publishing.
Abstract: Location-based services use location as contextual data to exclude irrelevant services from users. However almost all positioning technologies can only provide a location with a certain degree of accuracy. It is necessary to have a framework which can handle this inaccuracy and other uncertainties in order to provide a better and more adaptive service. In addition to positioning inaccuracy, location-based services can suffer from other aspects of uncertainty, such as data incompleteness and inconsistency. There is no universal positioning technique which can provide the position of the user seamlessly indoors and outdoors with an acceptable degree of accuracy. Consequently, it is possible to lose the position of the user for a period of time. To avoid this, some systems use more than one positioning technology, each having incomplete datasets; however they still may produce mutually inconsistent data. If an uncertain spatial dataset is stored and analysed in a framework which cannot handle uncertainty, some aspects of the input data may be missed and the outcome may not be fully applicable in real world applications. This chapter aims at developing a rough set-theory-based navigation application which can provide navigational instructions to users by taking spatial uncertainty into account.
BibTeX:
    @incollection{Liu2014a,
      author = {Basiri, Anahid and Amirian, Pouria and Winstanley, Adam and Moore, Terry and Hill, Chris},
      editor = {Liu, Chun},
      title = {Spatial Uncertainty Management in Pedestrian Navigation},
      booktitle = {Princ. Appl. Prog. Locat. Serv.},
      publisher = {Springer International Publishing},
      year = {2014},
      pages = {343--355},
      doi = {10.1007/978-3-319-04028-8}
    }
    
Basiri A, Jackson M, Amirian P, Pourabdollah A, Sester M, Winstanley A, Moore T and Zhang L (2016), "Quality assessment of OpenStreetMap data using trajectory mining", Geo-spatial Inf. Sci.. Vol. 19(1), pp. 56-68. Taylor & Francis.
BibTeX:
    @article{basiri2016quality,
      author = {Basiri, Anahid and Jackson, Mike and Amirian, Pouria and Pourabdollah, Amir and Sester, Monika and Winstanley, Adam and Moore, Terry and Zhang, Lijuan},
      title = {Quality assessment of OpenStreetMap data using trajectory mining},
      journal = {Geo-spatial Inf. Sci.},
      publisher = {Taylor & Francis},
      year = {2016},
      volume = {19},
      number = {1},
      pages = {56--68}
    }
    
Basiri A, Lohan ES, Figueiredo e Silva P, Peltola P, Hill C and Moore T (2014), "Overview of positioning technologies from fitness-to-purpose point of view", In Int. Conf. Localization GNSS. Helsinki, June, 2014. , pp. 1-7. IEEE.
Abstract: Even though Location Based Services (LBSs) are being more and more widely-used and this shows a promising future, there are still many challenges to deal with, such as privacy, reliability, accuracy, cost of service, power consumption and availability. There is still no single low-cost positioning technology which provides position of its users seamlessly indoors and outdoors with an acceptable level of accuracy and low power consumption. For this reason, fitness of positioning service to the purpose of LBS application is an important parameter to be considered when choosing the most suitable positioning technology for an LBS. This should be done for any LBS application, since each application may need different requirements. Some location-based applications, such as location-based advertisements or Location-Based Social Networking (LBSN), do not need very accurate positioning input data, while for some others, e.g. navigation and tracking services, highly-accurate positioning is essential. This paper evaluates different positioning technologies from fitness-to-purpose point of view for two different applications, public transport information and family/friend tracking.
BibTeX:
    @inproceedings{Basiri2014d,
      author = {Basiri, Anahid and Lohan, Elena Simona and Figueiredo e Silva, Pedro and Peltola, Pekka and Hill, Chris and Moore, Terry},
      title = {Overview of positioning technologies from fitness-to-purpose point of view},
      booktitle = {Int. Conf. Localization GNSS},
      publisher = {IEEE},
      year = {2014},
      pages = {1--7},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6934176},
      doi = {10.1109/ICL-GNSS.2014.6934176}
    }
    
Basiri A, Moore T, Hill C, Bhatia P and Anahid Basiri, Terry Moore, Chris Hill PB (2015), "Challenges of location-based services market analysis: current market description", In Prog. Locat. Serv. 2014. Cham , pp. 273-282. Springer International Publishing.
Abstract: Location-Based Services (LBS) have a huge and rapidly growing market, however LBS market reports do not fully agree about the current market size, the exact number of LBS users, market growth rate, etc. Different market study reports describe LBS market size, number of LBS subscribers and frequent users, revenues and costs and most appreciated application types with different and sometimes extremely contrasting numbers and figures and this becomes more problematic when it comes to forecasting the future market of LBS. One of the very first steps in any market analysis is defining business contribution area, which decides what should be included in or excluded from the market analysis. Location based services has got a large market; therefore it is not an easy task to identify LBS market's boundaries to analyse what is inside the box as LBS applications and exclude the rest. This paper explains the impact of such vague boundaries on market size estimation.
BibTeX:
    @incollection{basiri2015challenges,
      author = {Basiri, Anahid and Moore, Terry and Hill, Chris and Bhatia, Paul and Anahid Basiri, Terry Moore, Chris Hill, Paul Bhatia},
      editor = {Gartner, Georg and Huang, Haosheng},
      title = {Challenges of location-based services market analysis: current market description},
      booktitle = {Prog. Locat. Serv. 2014},
      publisher = {Springer International Publishing},
      year = {2015},
      pages = {273--282},
      doi = {10.1007/978-3-319-11879-6_19}
    }
    
Basiri A, Peltola P, Figueiredo e Silva P, Lohan ES, Moore T and Hill C (2015), "Indoor Positioning Technology Assessment using Analytic Hierarchy Process for Pedestrian Navigation Services", In Int. Conf. Localization GNSS. Gothenburg IEEE.
Abstract: Indoor positioning is one of the biggest challenges of many location-based applications and services. Providing users with accurate, reliable, cheap or free-to-use, low power consuming to calculate and continuously available positional data becomes even more challenging when pedestrians are the target users. People spend most of their time in roofed areas, such as houses, offices, airports, shopping centres and in general indoors. There are some positioning technologies that can be applied as stand-alone indoor positioning technologies. They include WLAN, BLE, UWB, RFID passive and active, tactile floor and high sensitivity GNSS. This paper evaluate the practicality and fitness-to-the-purpose of pedestrian navigation of each of these stand-alone positioning technology to identify the best one for the purpose of indoor pedestrian navigation. In this regard, the most important criteria defining a suitable positioning service for pedestrian navigation are identified and prioritised. They include accuracy, availability, cost, power consumption and privacy. Then, each technology is evaluated according to each criterion using Analytic Hierarchy Process (AHP) and finally the combination of all weighted criteria and technologies are being processed to identify the most suitable solution.
BibTeX:
    @inproceedings{Basiri2015,
      author = {Basiri, Anahid and Peltola, Pekka and Figueiredo e Silva, Pedro and Lohan, Elena Simona and Moore, Terry and Hill, Chris},
      title = {Indoor Positioning Technology Assessment using Analytic Hierarchy Process for Pedestrian Navigation Services},
      booktitle = {Int. Conf. Localization GNSS},
      publisher = {IEEE},
      year = {2015}
    }
    
Daniel O, Nurmi J and Lohan ES (2015), "Relaxed Direct Position Estimation as Strategy for Open-Loop GNSS Receivers", In Int. Conf. Localization GNSS. Gothenburg
Abstract: Direct Position Estimation (DPE) approach fully exploits geometrical relationships between receiver and observable global navigation satellite system satellites. In this paper, we present a novel method based on this approach especially suitable for navigation receivers implemented on the open-loop batch signal processing architecture. In contrast to DPE, the method brings benefits in terms of computational complexity whereas the position accuracy degradation is minimal. We make a performance comparison using an extensive Monte Carlo simulation that includes navigation signals buried in additive white Gaussian noise, as well as a realistic satellite constellation.
BibTeX:
    @inproceedings{Daniel2015,
      author = {Daniel, Ondrej and Nurmi, Jari and Lohan, Elena Simona},
      title = {Relaxed Direct Position Estimation as Strategy for Open-Loop GNSS Receivers},
      booktitle = {Int. Conf. Localization GNSS},
      year = {2015}
    }
    
Daniel O, Raasakka J, Peltola P, Frohle M, Rivero-Rodriguez A, Wymeersch H, Nurmi J, O. Daniel J. Raasakka PPMFAR-RHW and Nurmi J (2016), "Blind sub-Nyquist GNSS signal detection", In 2016 IEEE Int. Conf. Acoust. Speech, Signal Process.., November, 2016. , pp. 1-5.
Abstract: A satellite navigation receiver traditionally searches for positioning signals using an acquisition procedure. In situations, in which the required information is only a binary decision whether at least one positioning signal is present or absent, the procedure represents an unnecessarily complex solution. This paper presents a different approach for the binary detection problem with significantly reduced computational complexity. The approach is based on a novel decision metric which is utilized to design two binary detectors. The first detector operates under the theoretical assumption of additive white Gaussian noise and is evaluated by means of Receiver Operating Characteristics. The second one considers also additional interferences and is suitable to operate in a real environment. Its performance is verified using a signal captured by a receiver front-end.
BibTeX:
    @inproceedings{daniel_blind_2016,
      author = {Daniel, O and Raasakka, J and Peltola, P and Frohle, M and Rivero-Rodriguez, A and Wymeersch, H and Nurmi, J and O. Daniel J. Raasakka, P Peltola M Frohle A Rivero-Rodriguez H Wymeersch and Nurmi, J},
      title = {Blind sub-Nyquist GNSS signal detection},
      booktitle = {2016 IEEE Int. Conf. Acoust. Speech, Signal Process.},
      year = {2016},
      pages = {1--5},
      doi = {0}
    }
    
Daniel O, Wymeersch H and Nurmi J (2015), "Hybrid Cooperative Positioning in Harsh Environments", In 2015 IEEE Globecom Work. (GC Wkshps). , pp. 1-6.
Abstract: Hybrid cooperative positioning involves the combination of satellite pseudoranges with measurements based on terrestrial radio signals, with the aim to improve both coverage and accuracy. This paper presents a theoretical analysis of hybrid cooperative positioning in low signal-to-noise ratio environments, explicitly accounting for scenarios where receivers can receive signals but cannot decode navigation messages. We propose an extended pseudorange model, suitable for evaluation of measurements made by the receiver in these scenarios, as well as extended cooperation across agents attempting to enable satellite navigation functionality of receivers operating below signal-to-noise ratio threshold required for proper message decoding. The advantages of such extended cooperation are illustrated on a realistic scenario by means of the Cramer-Rao lower bound.
BibTeX:
    @inproceedings{7414083,
      author = {Daniel, O and Wymeersch, H and Nurmi, J},
      title = {Hybrid Cooperative Positioning in Harsh Environments},
      booktitle = {2015 IEEE Globecom Work. (GC Wkshps)},
      year = {2015},
      pages = {1--6},
      doi = {10.1109/GLOCOMW.2015.7414083}
    }
    
Figueiredo e Silva P, Daniel O, Nurmi J and Lohan E-S (2014), "Cyclostationary features of downsampled 802.11g OFDM signal for cognitive positioning systems", In Int. Symp. Wirel. Commun. Syst.. Barcelona , pp. 950-954. IEEE.
Abstract: In cognitive positioning systems, spectrum sensing methods play an important role to understand the surrounding spectrum. Due to their good performance under noisy environments, cyclostationary methods are commonly used to characterise the received signals. These methods require a higher computational cost and high sampling rates [1]. With that in mind, this paper uses real measurement data, acquired in an office environment, at different sampling rates, including rates below the Nyquist rate. The motivation is to show that the implementation burden of these methods can be reduced by using lower sampling frequencies, since the cyclic properties of the signals are still visible.
BibTeX:
    @inproceedings{Silva2014a,
      author = {Figueiredo e Silva, Pedro and Daniel, Ondrej and Nurmi, Jari and Lohan, Elena-Simona},
      title = {Cyclostationary features of downsampled 802.11g OFDM signal for cognitive positioning systems},
      booktitle = {Int. Symp. Wirel. Commun. Syst.},
      publisher = {IEEE},
      year = {2014},
      pages = {950--954},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6933490},
      doi = {10.1109/ISWCS.2014.6933490}
    }
    
Figueiredo e Silva P, Lohan ES, Pinchin J, Hill C and Moore T (2015), "On the Impact of Intra-System Interference for Ranging and Positioning with Bluetooth Low Energy", In Int. Work. Mob. Entity Localization Track. GPS-less Environ.. Seattle, USA , pp. 1-4.
Abstract: This paper focuses on the study of intra-system interference for ranging and positioning applications using Bluetooth Low Energy (BLE). While BLE tries to avoid interference with other protocols in the same frequency band, such as Wi-Fi, the intra-system interference is unavoidable, either due to multipath or simultaneous transmissions in the same channel. This study shows that intra-system interference contributes with a deviation of approximately 5 dBm in the Received Signal Strength (RSS) and by taking this into account the ranging and positioning accuracy can be significantly improved. The study uses data collected from two different environments.
BibTeX:
    @inproceedings{Figueiredo,
      author = {Figueiredo e Silva, Pedro and Lohan, Elena Simona and Pinchin, James and Hill, Chris and Moore, Terry},
      title = {On the Impact of Intra-System Interference for Ranging and Positioning with Bluetooth Low Energy},
      booktitle = {Int. Work. Mob. Entity Localization Track. GPS-less Environ.},
      year = {2015},
      pages = {1--4},
      doi = {10.1145/2830571.2830573}
    }
    
Figueiredo e Silva P and Simona-lohan E (2015), "Room-level indoor positioning with Wi-Fi and RFID fingerprints", In Int. Work. Mob. Entity Localization Track. GPS-less Environ.. S.
Abstract: This paper shows the advantages and limitations of combining RFID and Wi-Fi technology for estimating the location of a user in an indoor environment. The paper builds on on a simulated environment, with one or several RFID readers being deployed inside a room and several Wi-Fi devices spread, exclusively, around the surrounding area. The parameters of the simulated environment were drawn from a real measurement experiment.
BibTeX:
    @inproceedings{Figueiredo2015,
      author = {Figueiredo e Silva, Pedro and Simona-lohan, Elena},
      editor = {Jahankhani, Hamid and Carlile, Alex and Akhgar, Babak and Taal, Amie and Hessami, Ali G. and Hosseinian-Far, Amin},
      title = {Room-level indoor positioning with Wi-Fi and RFID fingerprints},
      booktitle = {Int. Work. Mob. Entity Localization Track. GPS-less Environ.},
      publisher = {S},
      year = {2015},
      doi = {10.1145/2830571.2830579}
    }
    
Figueiredo e Silva P and Simona-lohan E (2016), "Performance Considerations for Positioning with Signals of Opportunity", In Int. Conf. Localization GNSS. Barcelona
Abstract: This paper presents a study on the benefit of observing several signals of opportunity for positioning purposes. Several static emitters are placed over a defined area where an user is moving and acquiring measurements to each of these emitters. The simulation considers that the user is capable of acquiring time of arrival measurements from several wireless protocols, such as WCDMA, 802.11b, 802.11g and 802.11ac. The variance in the measurements is modelled through the Cr´ amer- Rao bound and a propagation model for each technology. As conclusions, this paper discusses the benefits of using multiple signals of opportunity in the context of positioning and how much the positioning performance is affected by considering different measurements combinations from several wireless technologies.
BibTeX:
    @inproceedings{Figueiredo2016,
      author = {Figueiredo e Silva, Pedro and Simona-lohan, Elena},
      title = {Performance Considerations for Positioning with Signals of Opportunity},
      booktitle = {Int. Conf. Localization GNSS},
      year = {2016}
    }
    
Figueiredo e Silva PM, Seco-Granados G and Simona-Lohan E (2015), "Receiver Architecture for Cognitive Positioning with CDMA and OFDM signals", In Int. Conf. Localization GNSS. Gothenburg IEEE.
BibTeX:
    @inproceedings{FigueiredoeSilva2015,
      author = {Figueiredo e Silva, Pedro Manuel and Seco-Granados, Gonzalo and Simona-Lohan, Elena},
      title = {Receiver Architecture for Cognitive Positioning with CDMA and OFDM signals},
      booktitle = {Int. Conf. Localization GNSS},
      publisher = {IEEE},
      year = {2015}
    }
    
Fröhle M and Wymeersch H (2015), "On the Separation of Time Scales in Positioning", In Int. Conf. Localization GNSS. Gothenburg
Abstract: Radio-based positioning methods are generally based on a separation of timescales, where each position update assumes the availability of synchronous measurements. This approach is convenient in the design of positioning algorithms, but fails to account for outdated information. We describe three distinct ways how the separation of timescales can adversely impact the design and execution of positioning methods, and quantify the extent of these impacts analytically.
BibTeX:
    @inproceedings{Frohle2015,
      author = {Fröhle, M. and Wymeersch, H.},
      title = {On the Separation of Time Scales in Positioning},
      booktitle = {Int. Conf. Localization GNSS},
      year = {2015}
    }
    
Frohle M, Zaidi AA, Strom E and Wymeersch H (2014), "Multi-step sensor selection with position uncertainty constraints", In IEEE Globecom Work.., dec, 2014. , pp. 1439-1444. IEEE.
Abstract: Research on localization systems has shifted from focusing mainly on accuracy towards a more cognitive design, accounting for communication constraints, energy limitations, and delay. This leads to a variety of sensor selection optimization problems that are solved using techniques from convex optimization. We provide a novel formulation of the sensor selection problem over an extended time horizon, aiming to minimize the sensing cost of an entire path while guaranteeing a certain position accuracy. We state algorithms for determining lower and upper bounds on the sensing cost and utilize these in a path selection problem for autonomous agents. Simulation results confirm the usefulness of our approach, where we observe a benefit of optimizing over longer time horizons in low to medium noise scenarios compared to a myopic sensor selection scheme.
BibTeX:
    @inproceedings{Frohle2014a,
      author = {Frohle, Markus and Zaidi, Ali A. and Strom, Erik and Wymeersch, Henk},
      title = {Multi-step sensor selection with position uncertainty constraints},
      booktitle = {IEEE Globecom Work.},
      publisher = {IEEE},
      year = {2014},
      pages = {1439--1444},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7063636}
    }
    
Gan M, Meissner P, Mani F, Leitinger E, Frohle M, Oestges C, Witrisal K and Zemen T (2014), "Calibration of indoor UWB sub-band divided ray tracing using multiobjective simulated annealing", In IEEE Int. Conf. Commun.., jun, 2014. , pp. 4844-4849. IEEE.
Abstract: Sub-band divided ray tracing (RT) has been widely used to reproduce as reliably as possible the ultra-wideband (UWB) radio wave propagation channel in realistic indoor environments. However, its accuracy is strictly limited by the available description of the environment. Moreover, its computational complexity scales with the number of selected subbands and the number of propagation paths. In the present work, our RT tool considers not only deterministic propagation paths but also diffuse scattering components. Based on a low-complexity sub-band divided RT implementation, we propose a calibration method for indoor UWB sub-band divided RT. The method estimates the optimal material parameters, including the dielectric parameters and the scattering parameters, using channel measurements and multiobjective simulated annealing (MOSA). This calibration can improve the accuracy of sub-band divided RT in terms of the power delay profile (PDP) and the root mean square (RMS) delay spread for all test locations including those not considered by the calibration. A measurement campaign is used to verify the calibration technique.
BibTeX:
    @inproceedings{Gan2014b,
      author = {Gan, Mingming and Meissner, Paul and Mani, Francesco and Leitinger, Erik and Frohle, Markus and Oestges, Claude and Witrisal, Klaus and Zemen, Thomas},
      title = {Calibration of indoor UWB sub-band divided ray tracing using multiobjective simulated annealing},
      booktitle = {IEEE Int. Conf. Commun.},
      publisher = {IEEE},
      year = {2014},
      pages = {4844--4849},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6884087}
    }
    
Gan M, Meissner P, Mani F, Leitinger E, Frohle M, Oestges C, Witrisal K and Zemen T (2014), "Low-complexity sub-band divided ray tracing for UWB indoor channels", In IEEE Wirel. Commun. Netw. Conf.., apr, 2014. , pp. 305-310. IEEE.
Abstract: Ray tracing has been extensively used to simulate indoor channel characteristics. For an ultra-wideband system, the channel characteristics vary significantly over the entire bandwidth. To cope with this, sub-band divided RT has been proposed by dividing the frequency of interest into multiple subbands and superposing the RT results at the individual center frequency of each subband. Thus, the computational complexity is directly proportional to the number of subbands. In this paper, we propose a mathematical method to significantly reduce the computational complexity of the sub-band divided RT, making it almost independent of the number of subbands. It is important to note that, based on our approach, not only the determination of the rays reaching a give location is made only once, but also the electromagnetic calculation of the received signal is not needed to perform repeatedly. The accuracy of low-complexity subband divided RT algorithm is verified through a measurement campaign.
BibTeX:
    @inproceedings{Gan2014c,
      author = {Gan, Mingming and Meissner, Paul and Mani, Francesco and Leitinger, Erik and Frohle, Markus and Oestges, Claude and Witrisal, Klaus and Zemen, Thomas},
      title = {Low-complexity sub-band divided ray tracing for UWB indoor channels},
      booktitle = {IEEE Wirel. Commun. Netw. Conf.},
      publisher = {IEEE},
      year = {2014},
      pages = {305--310},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6951985}
    }
    
Leitinger E, Froehle M, Meissner P and Witrisal K (2014), "Multipath-Assisted Maximum-Likelihood Indoor Positioning using UWB Signals", In COST Action IC1004 Manag. Comm. Meet.. Ferrara, Italy
BibTeX:
    @inproceedings{Leitinger2014f,
      author = {Leitinger, E. and Froehle, M. and Meissner, P. and Witrisal, K.},
      title = {Multipath-Assisted Maximum-Likelihood Indoor Positioning using UWB Signals},
      booktitle = {COST Action IC1004 Manag. Comm. Meet.},
      year = {2014}
    }
    
Leitinger E, Frohle M, Meissner P and Witrisal K (2014), "Multipath-assisted maximum-likelihood indoor positioning using UWB signals", In IEEE Int. Conf. Commun. Work.. Sydney, NSW, jun, 2014. , pp. 170-175. IEEE.
Abstract: Multipath-assisted indoor positioning (using ultrawideband signals) exploits the geometric information contained in deterministic multipath components. With the help of a-priori available floorplan information, robust localization can be achieved, even in absence of a line-of-sight connection between anchor and agent. In a recent work, the Crame\CC?r-Rao lower bound has been derived for the position estimation variance using a channel model which explicitly takes into account diffuse multipath as a stochastic noise process in addition to the deterministic multipath components. In this paper, we adapt this model for position estimation via a measurement likelihood function and evaluate the performance for real channel measurements. Performance results confirm the applicability of this approach. A position accuracy better than 2.5 cm has been obtained in 90% of the estimates using only one active anchor at a bandwidth of 2 GHz and robustness against non-line-of-sight situations has been demonstrated.
BibTeX:
    @inproceedings{Leitinger2014c,
      author = {Leitinger, Erik and Frohle, Markus and Meissner, Paul and Witrisal, Klaus},
      title = {Multipath-assisted maximum-likelihood indoor positioning using UWB signals},
      booktitle = {IEEE Int. Conf. Commun. Work.},
      publisher = {IEEE},
      year = {2014},
      pages = {170--175},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6881191},
      doi = {10.1109/ICCW.2014.6881191}
    }
    
Leitinger E, Meissner P, Frohle M and Witrisal K (2014), "Performance bounds for multipath-assisted indoor localization on backscatter channels", In IEEE Radar Conf.., may, 2014. , pp. 0070-0075. IEEE.
Abstract: In this paper, we derive the Cramer-Rao lower bound (CRLB) on the position error for an RFID tag localization system exploiting multipath on backscatter radio channels. The backscatter channel is modeled with a hybrid deterministic/stochastic channel model. In this way, both the geometry of the deterministic multipath components (MPCs) and the interfering diffuse multipath are taken into account. Computational results show the influence of the room geometry on the bound and the impact of the diffuse multipath. Time reversal (TR) processing on the uplink channel is analyzed using the deterministic MPCs to overcome the degenerate nature of the backscatter channel. The CRLB shows the potential gain obtained from TR processing as well as its strong dependence on the geometry. Such TR processing has been proposed for TX waveform adaptation in the perception-action cycle of a cognitive radar. The results of this paper illustrate that it can indeed influence beneficially the measurement noise of the received signal, yielding control over the localization system.
BibTeX:
    @inproceedings{Leitinger2014e,
      author = {Leitinger, Erik and Meissner, Paul and Frohle, Markus and Witrisal, Klaus},
      title = {Performance bounds for multipath-assisted indoor localization on backscatter channels},
      booktitle = {IEEE Radar Conf.},
      publisher = {IEEE},
      year = {2014},
      pages = {0070--0075},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6875557}
    }
    
Liu H, Meng X, Chen Z, Stephenson S and Peltola P (2015), "A closed-loop EKF and multi-failure diagnosis approach for cooperative GNSS positioning", GPS Solut.., sep, 2015.
Abstract: Current cooperative positioning with global navigation satellite system (GNSS) for connected vehicle application mainly uses pseudorange measurements. However, the positioning accuracy offered cannot meet the requirements for lane-level positioning, collision avoidance and future automatic driving, which needs real-time positioning accuracy of better than 0.5 m. Furthermore, there is an apparent lack of research into the integrity issue for these new applications under emerging driverless vehicle applications. In order to overcome those problems, a new extended Kalman filter (EKF) and a multi-failure diagnosis algorithm are developed to process both GNSS pseudorange and carrier phase measurements. We first introduce a new closed-loop EKF with partial ambiguity resolution as feedback to address the low accuracy issue. Then a multi-failure diagnosis algorithm is proposed to improve integrity and reliability. The core of this new algorithm includes using Carrier phase-based Receiver Autonomous Integrity Monitoring method for failure detection, and the double extended w test detectors to identify failure. A cooperative positioning experiment was carried out to validate the proposed method. The results show that the proposed closed-loop EKF can provide highly accurate positioning, and the multi-failure diagnosis method is effective in detecting and identifying failures for both code and carrier phase measurements.
BibTeX:
    @article{Liu2015a,
      author = {Liu, Haiying and Meng, Xiaolin and Chen, Zhiming and Stephenson, Scott and Peltola, Pekka},
      title = {A closed-loop EKF and multi-failure diagnosis approach for cooperative GNSS positioning},
      journal = {GPS Solut.},
      year = {2015},
      doi = {10.1007/s10291-015-0489-6}
    }
    
Lohan E-S, Talvitie J, Figueiredo e Silva P, Nurminen H, Ali-Löytty S and Piché R (2015), "Received Signal Strength models for WLAN and BLE-based indoor positioning in multi-floor buildings", In Int. Conf. Localization GNSS. Gothenburg
BibTeX:
    @inproceedings{Lohan2015a,
      author = {Lohan, Elena-Simona and Talvitie, Jukka and Figueiredo e Silva, Pedro and Nurminen, Henri and Ali-Löytty, Simo and Piché, Robert},
      title = {Received Signal Strength models for WLAN and BLE-based indoor positioning in multi-floor buildings},
      booktitle = {Int. Conf. Localization GNSS},
      year = {2015}
    }
    
Meyer F, Wymeersch H, Frohle M and Hlawatsch F (2015), "Distributed Estimation with Information-Seeking Control in Agent Networks", IEEE J. Sel. Areas Commun.. Vol. PP(99), pp. 1-1.
Abstract: We introduce a distributed, cooperative framework and method for Bayesian estimation and control in decentralized agent networks. Our framework combines joint estimation of time-varying global and local states with information-seeking control optimizing the behavior of the agents. It is suited to nonlinear and non-Gaussian problems and, in particular, to location-aware networks. For cooperative estimation, a combination of belief propagation message passing and consensus is used. For cooperative control, the negative posterior joint entropy of all states is maximized via a gradient ascent. The estimation layer provides the control layer with probabilistic information in the form of sample representations of probability distributions. Simulation results demonstrate intelligent behavior of the agents and excellent estimation performance for a simultaneous selflocalization and target tracking problem. In a cooperative localization scenario with only one anchor, mobile agents can localize themselves after a short time with an accuracy that is higher than the accuracy of the performed distance measurements.
BibTeX:
    @article{Meyer2015b,
      author = {Meyer, Florian and Wymeersch, Henk and Frohle, Markus and Hlawatsch, Franz},
      title = {Distributed Estimation with Information-Seeking Control in Agent Networks},
      journal = {IEEE J. Sel. Areas Commun.},
      year = {2015},
      volume = {PP},
      number = {99},
      pages = {1--1},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=7102683}
    }
    
Montasari R and Peltola P (2015), "Computer Forensic Analysis of Private Browsing Modes", In Glob. Secur. Saf. Sustain. Tomorrow's Challenges Cyber Secur.. London Vol. 534 Springer International Publishing.
Abstract: This paper investigates the effectiveness of the private browsing modes built into four major Internet browsers. In examining the phenomenon of the private browsing modes built into four widely used Internet browsers, this paper aims to determine whether one can identify when a private browsing mode has been utilized by a suspect to perform a criminal or illegal act and to what extent the forensic examination of a computer can expose evidence of private browsing use.
BibTeX:
    @incollection{Jahankhani2015a,
      author = {Montasari, R. and Peltola, Pekka},
      editor = {Jahankhani, Hamid and Carlile, Alex and Akhgar, Babak and Taal, Amie and Hessami, Ali G. and Hosseinian-Far, Amin},
      title = {Computer Forensic Analysis of Private Browsing Modes},
      booktitle = {Glob. Secur. Saf. Sustain. Tomorrow's Challenges Cyber Secur.},
      publisher = {Springer International Publishing},
      year = {2015},
      volume = {534},
      doi = {10.1007/978-3-319-23276-8_9}
    }
    
Montasari R, Peltola P and Evans D (2015), "Integrated Computer Forensics Investigation Process Model (ICFIPM) for Computer Crime Investigations", In Glob. Secur. Saf. Sustain. Tomorrow's Challenges Cyber Secur.. , pp. 361. Springer.
Abstract: Contrary to traditional crimes for which there exists deep-rooted standards, procedures and models upon which courts of law can rely, there are no formal standards, procedures nor models for digital forensics to which courts can refer. Although there are already a number of various digital investigation process models, these tend to be ad-hoc procedures. In order for the case to prevail in the court of law, the processes followed to acquire digital evidence and terminology utilised must be thorough and generally accepted in the digital forensic community. The proposed novel process model is aimed at addressing both the practical requirements of digital forensic practitioners and the needs of courts for a formal computer investigation process model which can be used to process the digital evidence in a forensically sound manner. Moreover, unlike the existing models which focus on one aspect of process, the proposed model describes the entire lifecycle of a digital forensic investigation.
BibTeX:
    @incollection{MontasariR.PeltolaP.andEvans2015,
      author = {Montasari, R. and Peltola, P. and Evans, D.},
      editor = {Jahankhani, Hamid and Carlile, Alex and Akhgar, Babak and Taal, Amie and Hessami, Ali G. and Hosseinian-Far, Amin},
      title = {Integrated Computer Forensics Investigation Process Model (ICFIPM) for Computer Crime Investigations},
      booktitle = {Glob. Secur. Saf. Sustain. Tomorrow's Challenges Cyber Secur.},
      publisher = {Springer},
      year = {2015},
      pages = {361},
      doi = {10.1007/978-3-319-23276-8_8}
    }
    
Nurmi J, Della Rosa F and Lohan E-S (2014), "MULTI-POS - multi-technology positioning professionals training network", In Int. Conf. Localization GNSS. Helsinki, jun, 2014. , pp. 1-4. IEEE.
Abstract: The global navigation market (products and services) is expected to grow to more than 160 billion EUR revenue by 2015 with significant growth being driven by mobile terminals. The pillars of the future wireless society will be the trustworthiness of the wireless positioning device and ecofriendliness of the transmission-reception process. These are triggered by the user needs, preferences and targeted applications, and by the type of the environment where navigation takes place. A link is still missing between these user needs/environment awareness (or application layer) and the physical layer where the wireless device is actually designed. The missing link can be created by cognitive approaches, borrowed on one hand from cognitive human behavior, and on the other hand from cognitive computing. Building a cognition stage between the application and physical layers will create a myriad of new possibilities for flexible location-based services and positioning-based applications, and possibly a new paradigm in wireless location research. MULTI-POS training network is bridging the gap between the lower technology layer and upper application layer involved in wireless mobile location. In addition, MULTI-POS will offer comprehensive training to young fellows in the broad field of wireless location, will create novel technologies and business models for the future location-enabled wireless devices, will promote the exchange of fellows in mixed academic-industrial R&D trajectories and in multiple European cultures, and will initiate an educational and research framework that unifies the currently fragmented research activities on technological and applications aspects of wireless navigation. There is strong involvement of industrial partners in the network to accomplish this.
BibTeX:
    @inproceedings{Nurmi2014a,
      author = {Nurmi, Jari and Della Rosa, Francescantonio and Lohan, Elena-Simona},
      title = {MULTI-POS - multi-technology positioning professionals training network},
      booktitle = {Int. Conf. Localization GNSS},
      publisher = {IEEE},
      year = {2014},
      pages = {1--4},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6934174},
      doi = {10.1109/ICL-GNSS.2014.6934174}
    }
    
Nykänen OA and Rivero Rodriguez A (2014), "Problems in Context-Aware Semantic Computing", Int. J. Interact. Mob. Technol.., jun, 2014. Vol. 8(3), pp. pp. 32--39.
Abstract: Acknowledging the user context, e.g., position and activity, provides a natural way to adapt applications according to the user needs. How to actually capture and exploit context, however, is not self-evident and it is tempting to assign the related responsibilities to individual context-consuming applications. Unfortunately, this confuses the user, complicates application development and hinders context-aware semantic computing as a research discipline. In this article, we outline context-aware semantic computing research topics and the state-of-the-art mobile application development frameworks of special interest to us, acknowledging best practices for accessing and modeling sensor context. From the integrated point of view, context-aware semantic computing is demonstrated in terms of a software component called context engine. In order to better understand how theory is tied with practice, we also introduce a simple context engine prototype. Finally, we use the research background and the empirical setting to discuss the significant problems and relevant research directions in context-aware semantic processing.
BibTeX:
    @article{nykanen_problems_2014,
      author = {Nykänen, Ossi Antero and Rivero Rodriguez, Alejandro},
      title = {Problems in Context-Aware Semantic Computing},
      journal = {Int. J. Interact. Mob. Technol.},
      year = {2014},
      volume = {8},
      number = {3},
      pages = {pp. 32----39},
      url = {http://online-journals.org/index.php/i-jim/article/view/3870}
    }
    
Nykänen O, Rivero-Rodriguez A, Pileggi P, Ranta PA, Kailanto M and Koro J (2015), "Associating Event Logs with Ontologies for Semantic Process Mining and Analysis", In Proc. 19th International Academic Mindtrek Conference. New York, NY, USA , pp. 138-143. ACM.
Abstract: Process mining uses various forms of event logs to extract process-related information, in order to discover, analyze conformance, or to enhance (business) processes. The vast majority of process mining applications are based on event logs with flat, keyword-based activity and resource descriptions. Many human-designed processes, however, are based on explicit workflow or lifecycle models with associated product models, both of which can be described using taxonomies or more complicated ontologies. This additional information can be used to analyze and visualize the processes with better insight of and improved formal access to the data. In this paper, we introduce a generic approach for enriching process mining using events logs with associated ontology structures. The main contribution and benefit of this approach lies in the ability to analyze the models in different abstraction levels, which greatly helps understanding complicated processes. Our main application areas are related to engineering and documentation processes.
BibTeX:
    @inproceedings{nykanen_associating_2015,
      author = {Nykänen, Ossi and Rivero-Rodriguez, Alejandro and Pileggi, Paolo and Ranta, Pekka A and Kailanto, Meri and Koro, Juho},
      title = {Associating Event Logs with Ontologies for Semantic Process Mining and Analysis},
      booktitle = {Proc. 19th International Academic Mindtrek Conference},
      publisher = {ACM},
      year = {2015},
      pages = {138--143},
      url = {http://doi.acm.org/10.1145/2818187.2818273},
      doi = {10.1145/2818187.2818273}
    }
    
Pileggi P, Rivero-Rodriguez A and Nykänen O (2015), "Using Context Overlays to Analyse the Role of a priori Information with Process Mining", In Int. Syst. Conf.. , pp. 639-644. IEEE.
Abstract: Notwithstanding the signi\EF\AC?cant advances in context-aware computing in pervasive computing and self-adaptive systems, there is still much more to be desired in providing better context services. The number of sensors deployed world-wide increases very rapidly. The Internet of Things, amongst others, generates vast amounts of data of many different data types. How data are used is essential to improve user experience and ef\EF\AC?ciencies of the systems in which they occur. We explain how familiar concepts of Process Mining strengthen generalised sensor context services. We present a laboratory case to explain the approach. By way of a real-world example, we con\EF\AC?rm the viability of using Process Mining to strengthen context-aware computing.
BibTeX:
    @inproceedings{Pileggi2015,
      author = {Pileggi, P. and Rivero-Rodriguez, A. and Nykänen, O},
      title = {Using Context Overlays to Analyse the Role of a priori Information with Process Mining},
      booktitle = {Int. Syst. Conf.},
      publisher = {IEEE},
      year = {2015},
      pages = {639--644}
    }
    
Pileggi P, Rivero-Rodriguez A and Nykänen O (2015), "Towards Traditional Simulation Models of Context Using Process Mining", In Int. Conf. Comput. Intell. Commun. Networks.
Abstract: Context (sensor) systems are hard to model: they require constant updating and insightful approaches, especially considering the increasing data volume, variety, and generation rate of contemporary networking paradigms, like the Internet of Things. In this paper, we argue that intelligent process models can be mined to look at the actual system activity from alternative context perspectives, i.e., perspectives observable from the sensor attributes themselves. We explain how the close relationship between the models derived using Process Mining, and Event-Driven Simulation can be exploited to help not only better understand what is happening in such systems but also provide alternative models for the intelligent solutions they support, such as context inference. We demonstrate this using a real-world example and discuss the feasibility of extending these alternative process models to be viewed as simulation. We envision automated steps that would result in traditional simulation models of context using Process Mining.
BibTeX:
    @inproceedings{Pileggi2015a,
      author = {Pileggi, P. and Rivero-Rodriguez, A. and Nykänen, O.},
      title = {Towards Traditional Simulation Models of Context Using Process Mining},
      booktitle = {Int. Conf. Comput. Intell. Commun. Networks},
      year = {2015}
    }
    
Raasakka J and Orejas M (2014), "Analysis of Notch Filtering Methods for Narrowband Interference Mitigation", In IEEE/ION PLANS. Monterey
Abstract: Interference, intentional and unintentional, is becoming a major threat for today's GNSS receivers. Several authors have presented notch filtering as an efficient mean to mitigate continuous wave or narrowband interference. Most of those studies, however, have focused only on the amount of signal energy preserved after filtering and limited amount of research has been done in analyzing the distortion of the autocorrelation function caused by the filtering process and its impact on the tracking performance. This study aims to analyze the effect of different notch filters on the autocorrelation function distortion. Research is conducted using simulations with actual PRN codes and for different modulations, namely BPSK(1), BPSK(10), BOC(1,1), and CBOC(6,1). Software simulations are then validated in a GNSS hardware prototype and it is shown that the results from the hardware prototype are consistent with the simulation results. Code and carrier tracking biases and error variance are defined as the key tracking performance indicators. Analysis of the notch filtering methods show that some of the proposed filter structures for filtering interference in GNSS receivers do not work well in practice and a great care should be taken when implementing filtering in the GNSS signal processing chain. In some cases, notch filtering should not be applied even though there is an interference signal present, as it will only degrade the GNSS receiver performance.
BibTeX:
    @inproceedings{Jussi,
      author = {Raasakka, J. and Orejas, M.},
      title = {Analysis of Notch Filtering Methods for Narrowband Interference Mitigation},
      booktitle = {IEEE/ION PLANS},
      year = {2014},
      url = {http://www.ion.org/plans/abstracts.cfm?paperID=1289}
    }
    
Rahman ML, Figueiredo e Silva P and Lohan E-S (2014), "Cyclostationarity-based spectrum sensing properties for signals of opportunity", In Int. Conf. Wirel. Mob. Comput. Netw. Commun.. Lanarca, oct, 2014. , pp. 390-395. IEEE.
Abstract: Performance enhancement in indoor positioning is one of the main concerns in recent days. Seeking such improvements, developments in navigation systems are employing Signals of Opportunity (SoO), meaning signals not originally developed for positioning purposes, such as wireless communication signals and Ultra Wideband (UWB) signals. Cyclostationary methods can provide necessary tools for signal detection for these systems. The detection part is only the first step towards cognitive positioning, and this is the part addressed in this paper. However, this work is not limited to cognitive positioning area, but it can find its usability in cognitive spectrum sensing as well. The aim of this paper is to provide a better understanding of the cyclostationary spectrum sensing properties of the most encountered modulations techniques for the SoO signals, namely CDMA, OFDM and TH-PPM UWB.
BibTeX:
    @inproceedings{Rahman2014b,
      author = {Rahman, Md. Lushanur and Figueiredo e Silva, Pedro and Lohan, Elena-Simona},
      title = {Cyclostationarity-based spectrum sensing properties for signals of opportunity},
      booktitle = {Int. Conf. Wirel. Mob. Comput. Netw. Commun.},
      publisher = {IEEE},
      year = {2014},
      pages = {390--395},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6962200},
      doi = {10.1109/WiMOB.2014.6962200}
    }
    
Rivero-Rodriguez A, Leppakoski H and Piche R (2014), "Semantic labeling of places based on phone usage features using supervised learning", In Ubiquitous Position. Indoor Navig. Locat. Based Serv. (UPINLBS), 2014. Corpus Christ, TX, nov, 2014. , pp. 97-102. IEEE.
Abstract: Nowadays mobile applications demand higher context awareness. The applications aim to understand the user's context (e.g., home or at work) and provide services tailored to the users. The algorithms responsible for inferring the user's context are the so-called context inference algorithms, the place detection being a particular case. Our hypothesis is that people use mobile phones differently when they are located in different places (e.g. longer calls at home than at work). Therefore, the usage of the mobile phones could be an indicator of the users' current context. The objective of the work is to develop a system that can estimate the user's place label (home, work, etc.), based on phone usage. As training and validation set, we use a database containing phone usage information of 200 users over several months including phone call and SMS logs, multimedia usage, accelerometer, GPS, network information and system information. The data was split into visits, i.e., periods of uninterrupted time that the user has been in a certain place (Home, Work, Leisure, etc.). The data include information about the phone usage during the visits, and the semantic label of the place visited (Home, Work, etc.). We consider two approaches to represent this data: the first approach (so-called visits approach) saves each visit separately; the second approach (so-called places approach) combines all visits of one user to a certain place and creates place-specific information. For place detection, we used five popular classification methods, Naïve Bayes, Decision Tree, Bagged Tree, Neural Network and K-Nearest Neighbors, in both representation approaches. We evaluated their classification rates and found that: 1) Bagged Tree outperforms the other methods; 2) the places data-representation gives better results than the visits data-representation.
BibTeX:
    @inproceedings{rivero-rodriguez_semantic_2014,
      author = {Rivero-Rodriguez, Alejandro and Leppakoski, Helena and Piche, Robert},
      title = {Semantic labeling of places based on phone usage features using supervised learning},
      booktitle = {Ubiquitous Position. Indoor Navig. Locat. Based Serv. (UPINLBS), 2014},
      publisher = {IEEE},
      year = {2014},
      pages = {97--102},
      url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7033715&sortType=ascpSequence&filter=AND(pISNumber:7033700)},
      doi = {10.1109/UPINLBS.2014.7033715}
    }
    
Rivero-Rodriguez A, Pileggi P and Nykänen O (2015), "Social Approach for Context Analysis: Modelling and Predicting Social Network Evolution Using Homophily", In Model. Using Context. (9405), pp. 513-519. Springer International Publishing.
Abstract: Understanding the user's context is important for mobile applications to provide personalized services. Such context is typically based on the user's own information. In this paper, we show how social network analysis and the study of the individual in a social network can provide meaningful contextual information. According to the phenomenon of homophily, similar users tend to be connected more frequently than dissimilar. We model homophily in social networks over time. Such models strengthen context inference algorithms, which helps determine future status of the user, resulting in prediction accuracy improvements of up to 118 % with respect to a naïve classifier.
BibTeX:
    @incollection{rivero-rodriguez_social_2015,
      author = {Rivero-Rodriguez, Alejandro and Pileggi, Paolo and Nykänen, Ossi},
      editor = {Christiansen, Henning and Stojanovic, Isidora and Papadopoulos, George A},
      title = {Social Approach for Context Analysis: Modelling and Predicting Social Network Evolution Using Homophily},
      booktitle = {Model. Using Context},
      publisher = {Springer International Publishing},
      year = {2015},
      number = {9405},
      pages = {513--519},
      url = {http://link.springer.com/chapter/10.1007/978-3-319-25591-041}
    }
    
Rivero-Rodriguez A, Pileggi P and Nykänen O (2015), "An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing", In Int. Conf. Comput. Intell. Commun. Networks. Riga
Abstract: The vast increase of personal sensor information is driving the rise in popularity of context-aware applications. Users crave and very often expect tailored services that are based on the users' context or personal preferences. The users themselves, using forms, often provide such information. An inference solution typically addresses this problem. In this paper, we present and show by way of a real-world example, the first step towards incorporating information of the user's social networking behavior in the inference task. We define an initial indicator of a particular social phenomenon, called Homophily, and describe how the indicator measures the presence of homophily at certain moments, also capturing the degree to which it is present. Different from existing indicators, ours lends itself to indicating the presence of homophily in a way that is easier to comprehend, so that it may be easily integrated into and reinforce context-aware semantic computing.
BibTeX:
    @inproceedings{Rivero-Rodriguez2015,
      author = {Rivero-Rodriguez, A. and Pileggi, P. and Nykänen, O.},
      title = {An Initial Homophily Indicator to Reinforce Context-Aware Semantic Computing},
      booktitle = {Int. Conf. Comput. Intell. Commun. Networks},
      year = {2015}
    }
    
Rivero-Rodriguez A, Pileggi P and Nykänen OA (2016), "Mobile Context-Aware Systems: Technologies, Resources and Applications", Int. J. Interact. Mob. Technol.. Vol. 10(2), pp. 25-32.
Abstract: Mobile applications often adapt their behavior according to user context, however, they are often limited to consider few sources of contextual information, such as user position or language. This article reviews existing work in context-aware systems (CAS), e.g., how to model context, and discusses further development of CAS and its potential applications by looking at available information, methods and technologies. Social Media seems to be an interesting source of personal information when appropriately exploited. In addition, there are many types of general information, ranging from weather and public transport to information of books and museums. These information sources can be combined in previously unexplored ways, enabling the development of smarter mobile services in different domains. Users are, however, reluctant to provide their personal information to applications; therefore, there is a crave for new regulations and systems that allow applications to use such contextual data without compromising the user privacy.
BibTeX:
    @article{rivero-rodriguez_mobile_2016,
      author = {Rivero-Rodriguez, Alejandro and Pileggi, Paolo and Nykänen, Ossi Antero},
      title = {Mobile Context-Aware Systems: Technologies, Resources and Applications},
      journal = {Int. J. Interact. Mob. Technol.},
      year = {2016},
      volume = {10},
      number = {2},
      pages = {25--32},
      url = {http://www.online-journals.org/index.php/i-jim/article/view/5367}
    }
    
Rosa FD, Paakki T, Nurmi J, Pelosi M and Rosa GD (2014), "Hand-grip impact on range-based cooperative positioning", In Int. Symp. Wirel. Commun. Syst.., aug, 2014. , pp. 728-732. IEEE.
Abstract: In this paper we present experimental evaluations of cooperative ranging-based approaches in mobile positioning. Our main contribution is represented by experimental investigations of the errors introduced by the hand-grip effect on cooperative schemes among peer devices, demonstrating that by knowing in real-time the particular orientation of the MS in a controlled experimental environment, it is possible to mitigate and filter out the effect of the hand-grip on RSS measurements and consequently to maintain the beneficial effect of the cooperation in the final position estimation.
BibTeX:
    @inproceedings{Rosa2014a,
      author = {Rosa, Francescantonio Della and Paakki, Tommi and Nurmi, Jari and Pelosi, Mauro and Rosa, Gianluca Della},
      title = {Hand-grip impact on range-based cooperative positioning},
      booktitle = {Int. Symp. Wirel. Commun. Syst.},
      publisher = {IEEE},
      year = {2014},
      pages = {728--732},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6933449}
    }
    
Sánchez-Naranjo S, Ramos-Pollán R and González FA (2014), "A Multicore Workflow for Inducing Data Driven GNSS Positioning Models", In CARLA HPC Lat. Am. High Perform. Comput. Conf.. Valparaíso, Chile
Abstract: Global Navigation Satellite Systems (GNSS) provide autonomous geo-spatial positioning with global coverage. Although there is widespread usage by the general public of the GPS service, the usage of GNSS in specialized fields (air navigation, precision agriculture, etc.) is not immediate, as the guarantee for several quality of service characteristics is not a given (precision, signal integrity, etc.). Thus, developing algorithms for GNSS positioning and error mitigation is key to enable their effective use. In this work, this problem is addressed using a data-driven, computing-intensive machine learning approach to induce positioning models. We exploit multicore parallelism to (1) generate positioning data from simulated satellite orbits and (2) use machine learning strategies to massively train models to predict receivers positions. The results herewith reported show desired scalability and precision behaviors, paving the way to use multicore systems to induce models for GNSS positioning and error mitigation.
BibTeX:
    @inproceedings{Sanchez-Naranjo2014,
      author = {Sánchez-Naranjo, Susana and Ramos-Pollán, Raúl and González, Fabio A.},
      title = {A Multicore Workflow for Inducing Data Driven GNSS Positioning Models},
      booktitle = {CARLA HPC Lat. Am. High Perform. Comput. Conf.},
      year = {2014}
    }
    
Shahmansoori A, Montalban R, Lopez-Salcedo JA and Seco-Granados G (2014), "Design of OFDM sequences for joint communications and positioning based on the asymptotic expected CRB", In Int. Conf. Localization GNSS. Helsinki, jun, 2014. , pp. 1-6. IEEE.
Abstract: A key aspect to design an OFDM system for combined positioning and high-data-rate communications is to find optimal data and pilot power allocations. Previously, A capacity maximizing design by taking into account the effects of channel and time-delay estimation for finite number of subcarriers and channel taps has been investigated. Increasing the number of subcarriers and channel taps make the matrix inversions in the non-asymptotic bounds close to singular or badly conditioned. Furthermore, computational complexity of such a system designed by non-asymptotic bounds grows significantly. In this paper, a method based on the asymptotic expected Crame\CC?r-Rao bound of joint time-delay and channel coefficients by increasing the number of subcarriers and channel taps has been proposed. The method reduces the complexity of the design considerably. Specifically, by increasing the number of channel taps the number of operations to compute matrix inversions is significantly reduced by asymptotic bounds. Numerical results show that as the number of subcarriers increases, the asymptotic bounds converge to the non-asymptotic bounds. Moreover, even for a finite number of subcarriers or channel taps the difference between joint data and pilot power allocations is negligible compared to the non-asymptotic expected Crame\CC?r-Rao bounds.
BibTeX:
    @inproceedings{Shahmansoori2014b,
      author = {Shahmansoori, Arash and Montalban, Rafael and Lopez-Salcedo, Jose A. and Seco-Granados, Gonzalo},
      title = {Design of OFDM sequences for joint communications and positioning based on the asymptotic expected CRB},
      booktitle = {Int. Conf. Localization GNSS},
      publisher = {IEEE},
      year = {2014},
      pages = {1--6},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6934168},
      doi = {10.1109/ICL-GNSS.2014.6934168}
    }
    
Shahmansoori A, Montalban R and Seco-Granados G (2014), "Optimal OFDM pilot sequences for time-delay and channel estimation based on the expected CRB for a large number of subcarriers", In Int. Work. Signal Process. Adv. Wirel. Commun.. Toronto, jun, 2014. , pp. 90-94. IEEE.
Abstract: A key aspect to design an OFDM system for combined positioning and high-data-rate communications is to find optimal data and pilot power allocations. Previous work has investigated the capacity maximizing design taking into account the effects of channel and time-delay estimation for finite number of subcarriers and channel taps. In this paper, we propose a method based on the asymptotic expected Crame\CC?r-Rao bound of joint time-delay and channel coefficients that reduces the complexity of the bounds by increasing the number of subcarriers or channel taps for data and pilot power allocations design. Specifically, for long channels a general form of matrix inversion, which is computationally complex, is converted to only the inversion at strong eigenvalues or pilots. Numerical results show that as the number of subcarriers increases, the non-asymptotic bounds converge to the asymptotic bounds at a fast speed. Moreover, even for a finite number of subcarriers or channel taps the difference between joint data and pilot power allocations is negligible compared to the non-asymptotic expected Crame\CC?r-Rao bounds.
BibTeX:
    @inproceedings{Shahmansoori2014c,
      author = {Shahmansoori, Arash and Montalban, Rafael and Seco-Granados, Gonzalo},
      title = {Optimal OFDM pilot sequences for time-delay and channel estimation based on the expected CRB for a large number of subcarriers},
      booktitle = {Int. Work. Signal Process. Adv. Wirel. Commun.},
      publisher = {IEEE},
      year = {2014},
      pages = {90--94},
      url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6941323&sortType%3DascpSequence%26filter%3DAND(pISNumber%3A6941301)},
      doi = {10.1109/SPAWC.2014.6941323}
    }
    
Shahmansoori A, Montalban R and Seco-Granados G (2014), "Effect of channel variability on pilot design for joint communications and positioning in OFDM", In Int. Symp. Wirel. Commun. Syst.. Barcelona, aug, 2014. , pp. 292-296. IEEE.
Abstract: The accuracy of the estimation of time-delay and channel coefficients in Orthogonal frequency division multiplexing (OFDM) communication systems can be improved by reducing the variability of channel coefficients, i.e. reducing channel covariance and increasing channel mean for a given power. First, we prove that the effect of channel variability between different OFDM symbols cannot be directly captured by extending expected Cramer Rao bound (ECRB) for one OFDM symbol to M OFDM symbols. Then, the effect of channel variations between different OFDM symbols is modeled as the variations of channel covariance and channel mean for one OFDM symbol and a given channel power. A pilot design approach based on per-symbol signal to noise and interference ratio (SINR) for a given time-delay estimation accuracy is investigated. The results show that reducing channel covariance and improving channel mean for a given channel power leads to more accurate estimation of time-delay and channel coefficients. Furthermore, one can save the total power for a given estimation accuracy and channel capacity.
BibTeX:
    @inproceedings{Shahmansoori2014e,
      author = {Shahmansoori, Arash and Montalban, Rafael and Seco-Granados, Gonzalo},
      title = {Effect of channel variability on pilot design for joint communications and positioning in OFDM},
      booktitle = {Int. Symp. Wirel. Commun. Syst.},
      publisher = {IEEE},
      year = {2014},
      pages = {292--296},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6933364},
      doi = {10.1109/ISWCS.2014.6933364}
    }
    
Shahmansoori A, Seco-Granados G and Wymeersch H (2015), "Robust Power Allocation for OFDM Wireless Network Localization", In IEEE Commun. Conf.. London
Abstract: Reliable and accurate localization of users is critical for many applications in wireless networks. In range-based localization, the position of a node (agent) can be estimated using distance measurements to nodes with known positions (anchors). Optimal power allocation of the anchors reduces positioning error and improves network lifetime and throughput. We formulate and solve a robust power allocation optimization problem with a constraint on the localization accuracy for multicast and unicast orthogonal frequency division multiplexing signals. The localization accuracy is expressed in terms of the expected squared position error bound, accounting for uncertainties in the wireless channel as well as in the agents' positions. Simulation results show that robust power allocation improves localization accuracy compared to non-robust power allocation, with only a limited power penalty.
BibTeX:
    @inproceedings{Shahmansoori2015,
      author = {Shahmansoori, Arash and Seco-Granados, Gonzalo and Wymeersch, Henk},
      title = {Robust Power Allocation for OFDM Wireless Network Localization},
      booktitle = {IEEE Commun. Conf.},
      year = {2015}
    }
    
Shytermeja E, Garcia-Pena A and Julien O (2015), "GNSS Signal Processing and Positioning Performance in Urban Environments", In Annu. Baska GNSS Conf. R. Inst. Navig..
Abstract: In the last decade, Global Navigation Satellites Systems (GNSS) have gained a significant position in the development of Urban Navigation applications and associated services. However, in dense urban environments such as city centers, traditional GNSS signal processing techniques are unable to provide an accurate and reliable position solution due to the frequent blockage/shadowing of the GNSS Line-Of-Sight (LOS) signals and due to the presence of multipath. In this paper, the implementation of an advanced step-by-step algorithm able to ensure increased accuracy and robustness of an integrated single frequency L1/E1 GPS/Galileo receiver aided by the video Fisheye camera is proposed. Our focus will be directed to the implementation design and analysis of the Vector Delay Frequency Lock Loop (VDFLL) tracking architecture, considered as an advanced GNSS signal processing technique, where the signal tracking and navigation solution tasks are jointly performed by the EKF navigation filter. The most evident advantages introduced by this method are robustness to momentary and individual satellite signal blockages, channel coupling and accumulative signal power facilitating the tracking of low C/N0 channels and an increased tracking performance in weak-signal or interference/jamming-affected environments. In this work, a detailed performance assessment of the proposed VDFLL architecture will be conducted in two distinctive levels, such as in the system level expressed in terms of user's position and velocity estimation accuracies and position/velocity errors bounding and resistance to degraded signal reception conditions and channel level, indicated by the code delay and carrier Doppler frequency accuracies.
BibTeX:
    @inproceedings{Shytermeja2015,
      author = {Shytermeja, Enik and Garcia-Pena, Axel and Julien, Olivier},
      title = {GNSS Signal Processing and Positioning Performance in Urban Environments},
      booktitle = {Annu. Baska GNSS Conf. R. Inst. Navig.},
      year = {2015}
    }
    
Shytermeja E, Garcia-Pena A and Julien O (2014), "Proposed architecture for integrity monitoring of a GNSS/MEMS system with a Fisheye camera in urban environment", In Int. Conf. Localization GNSS 2014 (ICL-GNSS 2014). Helsinki, jun, 2014. , pp. 1-6. IEEE.
Abstract: Recently, an increasing trend of GNSS-based Safety Critical (SC) or Liability Critical (LC) urban applications has been observed. These applications, associated to dense urban canyons, can have very stringent requirements in terms of accuracy, reliability and availability of the provided position solution. In this paper, the implementation of a step-by-step algorithm able to ensure the robustness and integrity monitoring of an integrated GPS/Galileo receiver with low-cost MEMS sensors and aided by the video Fisheye camera is proposed.
BibTeX:
    @inproceedings{Shytermeja2014a,
      author = {Shytermeja, Enik and Garcia-Pena, Axel and Julien, Olivier},
      title = {Proposed architecture for integrity monitoring of a GNSS/MEMS system with a Fisheye camera in urban environment},
      booktitle = {Int. Conf. Localization GNSS 2014 (ICL-GNSS 2014)},
      publisher = {IEEE},
      year = {2014},
      pages = {1--6},
      url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6934179},
      doi = {10.1109/ICL-GNSS.2014.6934179}
    }
    
Wang W, Figueiredo e Silva P and Lohan ES (2015), "Investigations on mobility models and their impact on indoor positioning", In Int. Work. Mob. Entity Localization Track. GPS-less Environ.. Seattle, USA
Abstract: This paper proposes a new mobility model more suitable for a user that moves in a 3D indoor space. A fingerprint- ing method is used to compare the performance of the new model with another feasible one found in literature. The software implementation is made available.
BibTeX:
    @inproceedings{Wang,
      author = {Wang, Wenbo and Figueiredo e Silva, Pedro and Lohan, Elena Simona},
      title = {Investigations on mobility models and their impact on indoor positioning},
      booktitle = {Int. Work. Mob. Entity Localization Track. GPS-less Environ.},
      year = {2015},
      doi = {10.1145/2830571.2830573}
    }