Mobile Information Systems - Volume 9, issue 2

Authors: Ahn, Junho | Han, Richard

Article Type: Research Article

Abstract: Mobile phones have become widely used for obtaining help in emergencies, such as accidents, crimes, or health emergencies. The smartphone is an essential device that can record emergency situations, which can be used for clues or evidence, or as an alert system in such situations. In this paper, we focus on mobile-based identification of potentially unusual, or abnormal events, occurring in a mobile user's daily behavior patterns. For purposes of this research, we have classified events …as "unusual" for a mobile user when an event is an infrequently occurring one from the user's normal behavior patterns – all of which are collected and recorded on a user's mobile phone. We build a general unusual event classification model to be automated on the smartphone for use by any mobile phone users. To classify both normal and unusual events, we analyzed the activity, location, and audio sensor data collected from 20 mobile phone users to identify these users' personalized normal daily behavior patterns and any unusual events occurring in their daily activity. We used binary fusion classification algorithms on the subjects' recorded experimental data and ultimately identified the most accurately performing fusion algorithm for unusual event detection. Show more

Keywords: Unusual event, mobile, pattern, classification, fusion, personal

DOI: 10.3233/MIS-130155

Citation: Mobile Information Systems, vol. 9, no. 2, pp. 99-122, 2013

Authors: Lee, Sungnam | Chon, Yohan | Cha, Hojung

Article Type: Research Article

Abstract: With the widespread use of smartphones, the use of location-based services (LBS) with smartphones has become an active research issue. The accurate measurement of user location is necessary to provide LBS. While outdoor locations are easily obtained with GPS, indoor location information is difficult to acquire. Previous work on indoor location tracking systems often relied on infrastructures that are influenced by environmental changes and temporal differences. Several studies have proposed infrastructure-less systems …that are independent of the surroundings, but these works generally required non-trivial computation time or energy costs. In this paper, we propose an infrastructure-less pedestrian tracking system in indoor environments. The system uses accelerometers and magnetic sensors in smartphones without pre-installed infrastructure. We reduced the cumulative error of location tracking by geo-magnetic observations at corners and spots with magnetic fluctuations. In addition, we developed a robust estimation model that is tolerant to false positives, as well as a mobility model that reflects the characteristics of multiple sensors. Extensive evaluation in a real environment indicates that our system is accurate and cost-effective. Show more

Keywords: Indoor localization system, unconstrained device placements, infrastructure-free

DOI: 10.3233/MIS-130156

Citation: Mobile Information Systems, vol. 9, no. 2, pp. 123-137, 2013

Authors: Rosa, Pedro M.P. | Rodrigues, Joel J.P.C. | Basso, Filippo

Article Type: Research Article

Abstract: In the last years, information flood is becoming a common reality, and the general user, hit by thousands of possible interesting information, has great difficulties identifying the best ones, that can guide him in his/her daily choices, like concerts, restaurants, sport gatherings, or culture events. The current growth of mobile smartphones and tablets with embedded GPS receiver, Internet access, camera, and accelerometer offer new opportunities to mobile ubiquitous multimedia applications that helps gathering the best …information out of an always growing list of possibly good ones. This paper presents a mobile recommendation system for events, based on few weighted context-awareness data-fusion algorithms to combine several multimedia sources. A demonstrative deployment were utilized relevance like location data, user habits and user sharing statistics, and data-fusion algorithms like the classical CombSUM and CombMNZ, simple, and weighted. Still, the developed methodology is generic, and can be extended to other relevance, both direct (background noise volume) and indirect (local temperature extrapolated by GPS coordinates in a Web service) and other data-fusion techniques. To experiment, demonstrate, and evaluate the performance of different algorithms, the proposed system was created and deployed into a working mobile application providing real time awareness-based information of local events and news. Show more

Keywords: Mobile computing, ubiquitous computing, location-aware, content-aware, iphone applications, multimedia applications, mobility

DOI: 10.3233/MIS-130157

Citation: Mobile Information Systems, vol. 9, no. 2, pp. 139-155, 2013

Authors: Kapus, Tatjana

Article Type: Research Article

Abstract: This paper concerns the formal modelling of medium access control in nonbeacon-enabled IEEE 802.15.4 wireless personal area networks with probabilistic timed automata supported by the PRISM probabilistic model checker. In these networks, the devices contend for the medium by executing an unslotted carrier sense multiple access with collision avoidance algorithm. In the literature, a model of a network which consists of two stations sending data to two different destination stations is introduced. We have improved this …model and, based on it, we propose two ways of modelling a network with an arbitrary number of sending stations, each having its own destination. We show that the same models are valid representations of a star-shaped network with an arbitrary number of stations which send data to the same destination station. We also propose how to model such a network if some of the sending stations are not within radio range of the others, i.e. if they are hidden. We present some results obtained for these models by probabilistic model checking using PRISM. Show more

Keywords: Wireless personal area networks, medium access control, hidden stations, formal specification, probabilistic model checking

DOI: 10.3233/MIS-130160

Citation: Mobile Information Systems, vol. 9, no. 2, pp. 157-188, 2013