Vilho Räisänen

Variation Needs in Service-Based Systems

Even though service-orientation has been widely applied, there still is a lack of systematic and tool independent development methods. Partly due to that, little attention has been paid to accounting for variation. When developing a service-based system, it is important to identify which types of variation are relevant for the project and when is the right time to model them. If the variation needs are not recognized or they are ignored, it may hinder applicability and reuse and results in inflexible systems. If they are considered too late, it may require a lot of redecisions and rework. In this paper we explore variation needs in terms of the development process of service-based systems. This study results in a categorization of variation in service-based systems. We illustrate the categorization in a small example in telecommunication area.

Service quality support-an overview

This article develops a system-level architectural framework for service quality in view of practical questions faced by network operators such as: what kind of combinations of mechanisms are needed for service quality support, given a particular access technology? Which systems are most future proof and easiest to manage? Issues considered in this article include technological alternatives, inherent application requirements, and end user viewpoint.

StaRe: Statistical Reasoning Tool for 5G Network Management

In operations of increasingly complex telecommunication networks, characterization of a system state and choosing optimal operation in it are challenges. One possible approach is to utilize statistical and uncertain information in the network management. This paper gives an overview of our work in which a Markov Logic Network model (MLN) is used for mobile network analysis with an RDF-based faceted search interface to monitor and control the behavior of the MLN reasoner. Our experiments, based on a prototype implementation, gives promising results of utilizing an ontology and MLN model in network status characterization, optimization and visualization.

Knowledge Modeling for Conflict Detection in Self-organized Networks

In this article, conflict detection between functions in self-organizing networks (SON) is reviewed. SON coordination is of crucial importance to management automation of fourth-generation networks. In particular, conflict detection is studied from knowledge management perspective. The advantages of model-based conflict detection over algorithmic alternatives are analyzed.

On end-to-end analysis of packet loss

End-to-end analysis of packet loss is presented, addressing both overall packet loss rate and loss correlations. Voice over IP is used as an application for which packet loss performance is analyzed. In addition to independent packet losses, concepts of temporal and spatial- or across-the-domain-correlations are analyzed and their applicability to end-to-end QoS analysis is discussed.

Combining ontological modelling and probabilistic reasoning for network management

Advanced automation is needed in future mobile networks to provide adequate service quality economically and with high reliability. In this paper, a system is presented that takes into account the network context, analyses uncertain information, and infers network configurations by means of probabilistic reasoning. The system introduced in this paper is an experimental platform integrating a mobile network simulator, a Markov Logic Network (MLN) model, and an OWL 2 ontology into a runtime environment that can be monitored via a Resource Description Framework (RDF) – based user interface. In this approach, the OWL ontology contains a semantic representation of the relevant concepts, and the MLN model evaluates elements of uncertain information. Experiments based on a prototype implementation demonstrate the value of semantic modelling and probabilistic reasoning in network status characterization, optimization, and visualization.

Sharing performance measurement events across domains

Network management activities, such as fault analysis and configuration management, are eventually related to changes in network measurements. Some measurement event might be either a trigger or objective of a management activity. We argue that sharing the semantics of performance data across networks provides a basis for more advanced automation. This paper presents an ontology-based system for sharing information about network measurements across network domains. The represented information contains correlations and human-defined mappings between network measurements and the system is based on semantic reasoning that identifies dependencies which arise by combining local and shared information. We demonstrate the usage of the system in a Long Term Evolution (LTE) network domain. Our experiments from an LTE simulator and LTE test network show that a combination of correlations, human-defined mappings, and ontological reasoning produces useful cross-domain information that can be accessed with ontology queries.

Information and Knowledge in Telecommunications: A Service-Dominant View

In this article, we explore the role of information and knowledge in telecommunications from the viewpoint of Service-Dominant Logic (SDL). We build on previous work on telecommunications service system analysis by emphasizing value propositions related to information and knowledge provided by vendors, system integrators, and providers of professional services. We argue that the importance of information and knowledge in telecommunications is increasing, facilitated by technologies such as Service-oriented Architectures (SOA) and cognitive networks as well as methodologies such as model-driven service engineering. This development is reflected in the value offerings of the industry. We present a service dominant and information/knowledge centric concept analysis of value from the viewpoint of Communications Service Provider (CSP) and illustrate it by means of examples.

Semantic Integration Platform

In this article, we describe an experimental platform for semantic integration of data models. Organized into components, the goal of the development of the platform has been accommodation of multiple use cases related to telecommunications. The components of the platform provide for interfacing and knowledge management functionalities. Anticipated use cases within telecommunications operability range from simple data exposition and federation to a platform for running applications benefiting from communications and reasoning capabilities.

A general method for analyzing and synthesizing loss patterns

A method for producing synthetic packet loss patterns for voice over IP (VoIP) speech quality testing is described that is based on actual measurements of packet losses. The method has been designed to make no assumptions of network loss behaviour and can produce synthetic test data for different packet durations.