ISSN 1312-2622

YEAR VII No. 1 / 2009

CONTENTS
Benefits of ICT Service Outsourcing
Comparative Analysis of Advanced Technologies for Processing of Large Data Sets
Nonlinear Path Following Control for a Bi-steerable Vehicle
Mobile GPS Navigation Application, Adapted to Visually Impaired People
On Interaction between Services Implemented on Different Service Platforms
Review of Algorithms for the Join Ordering Problem in Database Query Optimization

 

Benefits of ICT Service Outsourcing
O. Martikainen, P. Tyrvainen , E. Luoma
Key Words:
ITC-services, outsourcing, process changes, productivity.
Abstract
The research by Maliranta and Rouvinen based on the Finnish industrial statistics confirms that the productivity improvements from ICT services in firms correlate with organizational and process changes. These results implied a further question: Which types of process changes create the most beneficial productivity improvements in different environments. The research on process improvements has been done in ETLA, in the University of Jyväskylä and in the University of Oulu, where the Three Viewpoint Method (3VPM) [1, 12] was developed for the productivity analysis of process changes. In this paper we apply the 3VPM approach to analyze the outsourcing and multisourcing of ICT services from a group of SMEs to one ICT service company or to separate IT and network service companies. The question is can outsourcing improve the total productivity of these SME firms as service customers. Outsourcing is considered often as a synonym for offshoring, where the service tasks are performed abroad in a country where people are paid less. In our study we study outsourcing benefits without this type of salary reduction.

Comparative Analysis of Advanced Technologies for Processing of Large Data Sets
I.Valova, M. Noirhomme-Fraiture
Key Words:
On-line Analytic Data Processing; Data Mining, Symbolic Data Analysis and Visualization of data.
Abstract
In this paper the applied and theoretical results achieved, as well as some existing drawbacks in technologies for processing of large data sets-OLAP (On-line Analytic Processing), DM (Data Mining) and SDA (Symbolic Data Analysis) are analyzed. A comparative analysis is proposed on different types of data processing and the pros and cons of each one of them are highlighted. Here are discussed benefits and drawbacks of using data aggregates and visualization of large data set. Some topics of interest are shown for the purposes of additional scientific study, being specifically oriented to software applications. The paper is related with a joint implementation project between Bulgarian Academy of Science, ICSR, Sofia and CGRI/ Institut d’Informatique, FUNDP, Namur, Belgium.

Nonlinear Path Following Control for a Bi-steerable Vehicle
P. Petrov
Key Words:
Bi-steerable vehicle; path following; nonlinear control.
Abstract
This paper proposes a nonlinear feedback path control law for a bi-steerable vehicle (a four-wheel-steering vehicle designed to steer the rear wheels always in opposite direction to the front ones in function of the front steering angle). First, a kinematic model of the vehicle in error coordinates expressed in a moving reference frame, which is partially linked to the vehicle is developed. The control law is constructed using a backstepping recursive design technique yielding exponential stability of the closed-loop system in error coordinates and invariant properties with respect to the vehicle speed. Simulation results illustrate the effectiveness of the proposed controller.

Mobile GPS Navigation Application, Adapted to Visually Impaired People
R. Ivanov
Key Words:
GPS navigation for visually impaired; Java mobile applications.
Abstract
Java mobile application for GPS outdoor navigation and orientation, adapted for visually impaired people, is presented. The application will satisfy the special needs of the target user group - blind and visually impaired people. The main advantages of the proposed application are: it can be installed on low budged mobile phones with Java Virtual Machine (JVM); works with any external GPS receiver with Bluetooth interface or with integrated in mobile phone GPS; route planning without WEB server need; speech enabled multi-level menus in Bulgarian; speech navigation in an unknown environment; user can send alarm in case of danger or lost route.

On Interaction between Services Implemented on Different Service Platforms
E. Pencheva, G. Tsombov, I. Atanasov
Key Words:
Service interaction management, CAMEL services.
Abstract
To distinguish themselves from the competitors, mobile network operators offer value-added services based on Customized Application for Mobile Enhanced Logic (CAMEL) technology. It is usual for network operators to deploy these services implemented on different vendor-specific service platforms. The increased requirements of the subscribers for more services and the desire of network operators to reuse the existing infrastructure as far as possible impose integration of existing services. CAMEL allows only one service logic instance for a specific call segment at a time. To allow several service logic instances Service Capability Interaction Manager (SCIM) can be applied. In the paper the use of SCIM for this purpose is explained and verified by examples. Different service interaction scenarios are investigated and the required functionality of service interaction manager is synthesized.

Review of Algorithms for the Join Ordering Problem in Database Query Optimization
S. Vellev
Key Words:
Query optimization; join ordering, relational databases; query execution plan; deterministi c algorithms; randomized algorithms; genetic algorithms; hybrid algorithms.
Abstract
Finding the optimal join ordering for a database query is a complex combinatorial optimization problem which has been approached by a wide variety of strategies and algorithms, ranging from simple deterministic search to complex hybrid algorithms based on genetic search and incorporating domain-specific heuristics. In this paper we review a set of join ordering algorithms and classify them according to the nature of the search strategy they implement. We also briefly discuss the relative advantages and applicability of different algorithms.

The John Atanasoff Society of Automatics and Informatics

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