Niko Kotilainen’s research while affiliated with University of Jyväskylä and other places

The most usable user-interface is not necessarily the most popular. For example, the extent to which an interaction is based on graphics can depend highly on convention rather than usability. This study compares contemporary flight search applications in order to investigate whether a more extensive use of graphics can enhance usability. Two user-interfaces are compared: one follows the ideal principles of graphical user-interfaces and direct manipulation, while the second interface requires text to be entered with a keyboard. The results of the comparison indicate that even an early prototype of the graphics based alternative performed better than the typical formula based search application for several measurements of usability.

This paper presents an indoor positioning system based on FM radio. The system is built upon commercially available, short-range FM transmitters. The features of the FM radio which make it distinct from other localisation technologies are discussed. Despite the low cost and o-the-shelf components, the performance of the FM positioning is comparable to that of other positioning technologies (such as Wi-Fi). From our experiments, the median accuracy of the system is around 1.3 m and in 95% of cases the error is below 4.5 m.

Remote controlling of industrial systems requires a special approach. There are requirements for both the connection and the access terminals. The connection should provide users with reliability, security and quality, and the access terminals should be able to perform the required task. One important and at the same time a problematic requirement for a mobile controlling system is bidirectional access. In this paper we describe a system which enables bidirectional data access within 3G cellular network using a commercial service, and a prototype application for quality and usability for task performance using a terminal recognition methods.

This chapter proposes a neural network based approach for solving the resource discovery problem in Peer to Peer (P2P) networks and an Adaptive Global Local Memetic Algorithm (AGLMA) for performing in training of the neural network. The neural network, which is a multi-layer perceptron neural network, allows the P2P nodes to efficiently locate resources desired by the user. The necessity of testing the network in various working conditions, aiming to obtain a robust neural network, introduces noise in the objective function. The AGLMA is a memetic algorithm which employs two local search algorithms adaptively activated by an evolutionary framework. These local searchers, having different features according to the exploration logic and the pivot rule, have the role of exploring decision space from different and complementary perspectives. Furthermore, the AGLMA makes an adaptive noise compensation by means of explicit averaging on the fitness values and a dynamic population sizing which aims to follow the necessity of the optimization process. The numerical results demonstrate that the proposed computational intelligence approach leads to an efficient resource discovery strategy and that the AGLMA outperforms an algorithm classically employed for executing the neural network training.

This paper shows that the performance of peer-to-peer resource discovery algorithms is upper bounded by a k-Steiner minimum tree and proposes an algorithm locating near-optimal query paths for the peer-to-peer resource discovery problem. Global knowledge of the topology and the resources from the peer-to-peer network are required as an input to the algorithm. The algorithm provides an objective measure for defining how good local search algorithms are. The performance is evaluated in simulated peer-to-peer scenarios and in the measured Gnutella2 P2P network topology with four local search algorithms: breadth-first search, self-avoiding random walker, highest degree search and Dynamic Query Protocol.

This article presents mobile encounter networks (MENs), which emerge when mobile devices come across each other and form a temporary connection between them using a common short-range radio technology. Local information exchanges between mobile devices results in a broadcast diffusion of information to other users of the network with a delay. Gasoline price comparison system (GPCS), which delivers newest gasoline prices to mobile users using mobile encounter information diffusion, is described as well as other application areas where MENs could be used. The feasibility of building MENs using bluetooth is tested with the BlueCheese mobile encounter network middleware and it is found that the bluetooth currently present in mobile phones does not adequately suit as a network technology for MENs.

During the last years progress in Web search engines has been made to the point that relevant information can be reached easily most of the time. However very little empirical research has been carried to study Web search in highly dynamic social network environments composed of mobile devices. The aim of this work was therefore to investigate novel approaches that took advantage of the social network environment inherent to mobile peer-to-peer paradigm. The work focused mainly on the development of a prototype for mobile search concept. The prototype was built on top of Drupal content site management system. This study suggests that the methods presented can be a complement to traditional Web search engines.

In both academia and industry, peer-to-peer (p2p) applications have attracted great attention. This paper introduces and implemented a novel location-based multimedia application, the Multimedia Traveling Journal application (PhotoJournal) that employs the p2p paradigm and enables location-based content sharing among mobile users.

Mobile search prototype demonstrates the possibilities of social network search in N800 mobile devices. Search is initiated from a N800 mobile device to search the contacts in mobile device's addressbook. The contacts can be other N800 mobile devices running mobile Web server or normal Web servers in the Internet with Drupal content management system. Mobile device users can select which of their personal information such as phone numbers, calendar data etc. to share via a mobile Web server. The proposed search mechanism has many benefits compared to centralized Web search engines like Google. The search can locate information which is not referenced anywhere and thus allows hidden or rare information to be found. The search is executed realtime and does not provide outdated links. The search is directed to persons close in the social network and thus provides results which are more likely to be relevant to the querier. However, for searching popular data accessible via centralized servers mobile search is not well suited.

PhotoJournal is a novel location-based media sharing appli- cation that enables users to build interactive journals that associate multimedia files with locations on maps and share this information with other users. Its underlying informa- tion discovery and sharing mechanism is 7DS that runs in either pure peer-to-peer or centralized server-to-client mode, depending on the availability of a server and/or an infras- tructure. 7DS-enabled devices act as miniature caches, shar- ing information with each other. When access to an informa- tion server (e.g., web server) is not available, the local 7DS instance running on the device enables the device to search and access information from other peers in proximity. We have implemented the prototype and evaluated the delay to access the data using three testbeds. Two of these testbeds employ a centralized (server-to-client) architecture, while the third one applies the peer-to-peer paradigm. Depend- ing on the underlying network technology and device capa- bilities, this delay varies. The results encourage us to per- form additional empirical-based studies under increased traf- fic load conditions and initiate a user-study in the premises of a museum and a research park.