Jari Veijalainen

Developing GIS-supported location-based services

Mobile networking is developing and proliferating at a high speed. Many estimates say that the number of mobile telecom subscribers will exceed 1 billion in the year 2003. Among the terminals deployed, there will be hundreds of millions of Internet-enabled ones making Mobile Internet a reality for the big masses. The terminals and/or the mobile networks are now able to determine the position of the terminal on the earth with more and more precision. This is the basis for the new class of services called Location-Based Services (LBS). The paper discusses this new emerging application area that some people consider the central novel application class of Mobile Internet. The main topic of the paper is the question, how Geographic Information Systems (GIS) and the data hosted currently by them could be used in the context of LBS. We analyze their properties and relate them with the needs of LBS. We also present our LBS pilot system that is using XML-based vector formal for city maps and runs on Java-enabled mobile terminals, PDAs and smartphones.

2PC Agent method: achieving serializability in presence of failures in a heterogeneous multidatabase

A method for integrated concurrency control and recovery, applicable to heterogeneous multidatabase systems, is proposed. The responsibility for two-phase local commitment and recovery of the prepared state at participants is taken over by an entity called 2PC Agent. The main importance of the method is in preserving global serializability in the presence of a certain class of participant-related failures. The related recovery methods, including a novel failure-time optimistic concurrency control method, are presented.<<ETX>>

Prepare and commit certification for decentralized transaction management in rigorous heterogeneous multidatabases

Algorithms for scheduling of distributed transactions in a heterogeneous multidatabase, in the presence of failures, are presented. The algorithms of prepare certification and commit certification protect against serialization errors called global view distortions and local view distortions. View serializable overall histories are guaranteed in the presence of most typical failures. The assumptions are, among others, that the participating database systems produce rigorous histories and that no local transaction may update the data accessed by a global transaction that is in the prepared state. The main advantage of the method, as compared to other known solutions, is that it is totally decentralized.<<ETX>>

Mobile Electronic Commerce: Emerging Issues

There are many definitions for Mobile Electronic Commerce (M-Commerce). We define M-Commerce as any type of transaction of an economic value having at least at one end a mobile terminal and thus using the mobile telecommunications network. The Wireless Application Protocol (WAP) plays an important role in m-commerce by optimizing Internet standards for the constraints of the wireless environment and thus bridging the gap between Internet and mobile world. Mobile Network Operators can play a major role in m-commerce by being strategically positioned between customers and content/service providers. In this paper we investigate the roles the operator can play in m-commerce and discuss respective problems and emerging issues.

A survey of serendipity in recommender systems

We summarize most efforts on serendipity in recommender systems.We compare definitions of serendipity in recommender systems.We classify the state-of-the-art serendipity-oriented recommendation algorithms.We review methods to assess serendipity in recommender systems.We provide the future directions of serendipity in recommender systems. Recommender systems use past behaviors of users to suggest items. Most tend to offer items similar to the items that a target user has indicated as interesting. As a result, users become bored with obvious suggestions that they might have already discovered. To improve user satisfaction, recommender systems should offer serendipitous suggestions: items not only relevant and novel to the target user, but also significantly different from the items that the user has rated. However, the concept of serendipity is very subjective and serendipitous encounters are very rare in real-world scenarios, which makes serendipitous recommendations extremely difficult to study. To date, various definitions and evaluation metrics to measure serendipity have been proposed, and there is no wide consensus on which definition and evaluation metric to use. In this paper, we summarize most important approaches to serendipity in recommender systems, compare different definitions and formalizations of the concept, discuss serendipity-oriented recommendation algorithms and evaluation strategies to assess the algorithms, and provide future research directions based on the reviewed literature.

Distributed PIN verification scheme for improving security of mobile devices

The main driving force for the rapid acceptance rate of small sized mobile devices is the capability to perform e-commerce transactions at any time and at any place, especially while on the move. There are, however, also weaknesses of this type of e-commerce, often called mobile e-commerce, or m-commerce. Due to their small size and easy portability mobile devices can easily be lost or stolen. Whereas the economic values and privacy threats protected with Personal Identification Numbers (PIN) are not particularly high for normal voice-enabled mobile phones, this is not true any more when phones have developed to Personal Trusted Devices (PTDs). Still, PINs are used also in this new context for authorization and identification purposes. PINs are currently used both for protection of the devices and for authentication, as well as authorization of the users. It is commonly recognized that not many techniques of storing the PINs into the memory of the device or on the SIM card are safe. Even less sophisticated thieves might uncover the PIN inside the stolen mobile devices and for sophisticated thieves uncovering the PIN stored “safely” might be possible. In this paper we propose a new scheme to cope with the problem of uncovering the PIN that reduces the risks of m-commerce. The basic idea is that instead of storing the entire PIN digits (or some hash value) in the mobile device, we store part of the PIN in a remote machine in the network. The PIN verification then involves both the mobile device and the remote machine, which must verify their respective parts of the PIN. Also, the improvements of the security over the existing schemes are shown using a probabilistic model. In the best case, where the probability of discovering the PIN irrespective of the storage scheme is negligible in relation to directly uncovering it, the increase in security is over 1000%.

Reusability and modularity in transactional workflows

Abstract Workflow management techniques have become an intensive area of research in information systems. In large scale workflow systems modularity and reusability of existing task structures with context dependent (parameterized) task execution are essential components of a successful application. In this paper we study the issues related to management of modular transactional workflows, i.e., workflows that reuse component tasks and thus avoid redundancy in design. The notion of parameterized transactional properties of workflow tasks is introduced and analyzed, and the underlying architectural issues are discussed.

A Generic Architecture for a Social Network Monitoring and Analysis System

This paper describes the architecture and a partial implementation of a system designed for the monitoring and analysis of communities at social media sites. The main contribution of the paper is a novel system architecture that facilitates long-term monitoring of diverse social networks existing and emerging at various social media sites. It consists of three main modules, the crawler, the repository and the analyzer. The first module can be adapted to crawl different sites based on ontology describing the structure of the site. The repository stores the crawled and analyzed persistent data using efficient data structures. It can be implemented using special purpose graph databases and/or object-relational database. The analyzer hosts modules that can be used for various graph and multimedia contents analysis tasks. The results can be again stored to the repository, and so on. All modules can be run concurrently.

Transactions in Mobile Electronic Commerce

With the development of global networking, invention of WWW, and proliferation of Internet-enabled computer hardware and software into homes and pockets, a huge customer base has been created for electronic commerce. It is rapidly expanding in USA and Europe and Japan are following the trend. So far, the development of E-commerce has happened in a rather unregulated way especially in USA, whereas in Europe the European Commission has been developing a regulatory basis mainly in form of directives. Currently (12/1999) they have not yet all been accepted and a major restructuring of the regulatory framework has also been planned. Another technological development is the rapid growth of mobile computing, especially through WAP technology, which makes also mobile E-commerce possible. In this article we review the need of a transaction model and the corresponding transactional mechanism and its usefulness for E-commerce in general and for mobile E-commerce in particular. We tackle the issue both theoretically and empirically. In the theoretical part we review some of the earlier work, and discuss especially money atomicity, goods atomicity and certified delivery. The empirical part consists of trials at three E-commerce sites, two in Finland and one in USA and reveal important differences in the structure of E-commerce transactions in different cases. These must be taken into consideration when transactional support is developed further. Using the emerging technology both customer and merchant can now become mobile, although it is more probable that a customer is mobile but a merchant stationary. Communication autonomy and other autonomy aspects and miniature size of the terminals aggravate the problems of achieving the various levels of atomicity. Security, privacy, authentication, and authorization are of paramount importance in an open network environment. One important conclusion is that the transactional mechanism must be closely related with these aspects and that the main goal of using the transactional mechanism is actually to support security, privacy, authentication and authorization -- and vice versa.

Using agents to improve security and convenience in mobile e-commerce

The main driving force for the rapid acceptance rate of small sized mobile devices to do e-commerce is its increased convenience and efficiency in performing simple transactions compared with the stationary machines. Two of the weaknesses of this type of e-commerce are: (1) due to its small size, a mobile device can easily get lost and get stolen; (2) and it is neither very convenient nor cheap for a mobile user to perform transactions that require more than just a few messages, scanning of catalogues, or negotiations. Personal identification numbers (PIN) are currently used both for protection of the devices and for authentication of the user to solve (1). Sophisticated thefts might still uncover the PIN inside the mobile devices. (2) has not deserved much attention by the research community so far. We propose to use agent technology to cope with both problems. The related protocols are presented and the improvements on the security over the existing schemes are studied.The main driving force for the rapid acceptance rate of small sized mobile devices to do e-commerce is its increased convenience and efficiency in performing simple transactions compared with the stationary machines. Two of the weaknesses of this type of e-commerce are: (1) due to its small size, a mobile device can easily get lost and get stolen; (2) it is neither very convenient nor cheap for a mobile user to perform transactions that require more than just a few messages, scanning of catalogues, or negotiations. Personal identification numbers (PIN) are currently used both for protection of the devices and for authentication of the user to solve (1). Sophisticated thieves might still uncover the PIN inside the mobile devices. (2) has not deserved much attention by the research community so far. In this paper, we propose to use agent technology to cope with both problems. The related protocols are presented and the improvements on the security over the existing schemes are studied.