Investigation of interface between Multimedia IP Network and Call Processing Server in 3G IP Telephony Core Network

The thesis presents an overview of third generation of IP telephony. The architecture of 3G IP Telephony and its components are described. The main goal of the thesis is to investigate the interface between the Call Processing Server and Multimedia IP Networks. The interface functionality, proposed protocol stack and a general description are presented in the thesis. To provide useful services, 3G IP Telephony requires a set of control protocols for connection establishment, capabilities exchange and conference control. The Session Initiation Protocol (SIP) and the H.323 are two protocols that meet these needs. In the thesis these two protocols are investigated and compared in terms of Complexity, Extensibility, Scalability, Services, Resource Utilization and Management.

Adaptive optimization schemes for mobile VoIP applications Battery life and call quality aspects

In this thesis programmatic, application-layer means for better energy-efficiency in the VoIP application domain are studied. The work presented concentrates on optimizations which are suitable for VoIP-implementations utilizing SIP and IEEE 802.11 technologies. Energy-saving optimizations can have an impact on perceived call quality, and thus energy-saving means are studied together with those factors affecting perceived call quality. In this thesis a general view on a topic is given. Based on theory, adaptive optimization schemes for dynamic controlling of application's operation are proposed. A runtime quality model, capable of being integrated into optimization schemes, is developed for VoIP call quality estimation. Based on proposed optimization schemes, some power consumption measurements are done to find out achievable advantages. Measurement results show that a reduction in power consumption is possible to achieve with the help of adaptive optimization schemes.

Components of customer value in nurse call solutions

This study aimed to identify the value components of nurse call solutions. The value creation of such systems was analyzed by using a framework that was created based on the existing customer value literature. The empirical part of the study was conducted as a multiple-case study by using qualitative research methods. The data for the analysis was gathered through structured interviews in ten Finnish eldercare centers. The results indicate that a nurse call solution creates value for eldercare centers by increasing the safety of the residents, and by improving the efficiency of the staff while also providing cost savings.

Applications of graph transformation in tools for domain-specific modeling languages

The use of domain-specific languages (DSLs) has been proposed as an approach to cost-e ectively develop families of software systems in a restricted application domain. Domain-specific languages in combination with the accumulated knowledge and experience of previous implementations, can in turn be used to generate new applications with unique sets of requirements. For this reason, DSLs are considered to be an important approach for software reuse. However, the toolset supporting a particular domain-specific language is also domain-specific and is per definition not reusable. Therefore, creating and maintaining a DSL requires additional resources that could be even larger than the savings associated with using them. As a solution, di erent tool frameworks have been proposed to simplify and reduce the cost of developments of DSLs. Developers of tool support for DSLs need to instantiate, customize or configure the framework for a particular DSL. There are di erent approaches for this. An approach is to use an application programming interface (API) and to extend the basic framework using an imperative programming language. An example of a tools which is based on this approach is Eclipse GEF. Another approach is to configure the framework using declarative languages that are independent of the underlying framework implementation. We believe this second approach can bring important benefits as this brings focus to specifying what should the tool be like instead of writing a program specifying how the tool achieves this functionality. In this thesis we explore this second approach. We use graph transformation as the basic approach to customize a domain-specific modeling (DSM) tool framework. The contributions of this thesis includes a comparison of di erent approaches for defining, representing and interchanging software modeling languages and models and a tool architecture for an open domain-specific modeling framework that e ciently integrates several model transformation components and visual editors. We also present several specific algorithms and tool components for DSM framework. These include an approach for graph query based on region operators and the star operator and an approach for reconciling models and diagrams after executing model transformation programs. We exemplify our approach with two case studies MICAS and EFCO. In these studies we show how our experimental modeling tool framework has been used to define tool environments for domain-specific languages.

”They Call it Christmas”. An Ethnological Analysis of Alienation in Tove Jansson’s Short Story The Fir Tree

Artikel i tidskrift med referee-praxis

Verification and Implementation of Call Sequence Analysing Algorithm

Työssä arvioidaan ja verifioidaan puheluiden luokitteluun suunniteltu Call Sequence Analysing Algorithm (CSA-algoritmi). Algoritmin tavoitteena on luokitella riittävän samankaltaiset puhelut ryhmiksi tarkempaa vika-analyysia varten. Työssä esitellään eri koneoppimisalgoritmien pääluokitukset ja niiden tyypilliset eroavaisuudet, eri luokitteluprosesseille ominaiset datatyypit, sekä toimintaympäristöt, joissa kyseinen toteutus on suunniteltu toimivaksi. CSA-algoritmille syötetään verkon ylläpitoviesteistä koostuvia viestisarjoja, joiden sisällön perusteella samankaltaiset sarjat ryhmitellään kokonaisuuksiksi. Algoritmin suorituskykyä arvioidaan 94 käsin luokitellun verrokkisarjan avulla. Sarjat on kerätty toimivasta 3G-verkon kontrollerista. Kahta sarjaa vertailemalla sarjaparille muodostetaan keskinäinen tunnusluku: sarjojen samanlaisuutta kuvaava etäisyys. Tässä työssä keskitytään erityisesti Hamming-etäisyyteen. Etäisyyden avulla sarjat koostetaan ryhmiksi. Muuttamalla hyväksyttävää maksimietäisyyttä, jonka perusteella kaksi sarjaa lasketaan kuuluvaksi samaan ryhmään, saadaan aikaiseksi alaryhmiä, joihin kuuluu ainoastaan samankaltaisia sarjoja. Hyväksyttävän etäisyyden kasvaessa, myös virheluokitusten määrä kasvaa. Oikeiden lajittelutulosten vertailukohteena toimii käsin luokiteltu ryhmittely. CSA-algoritmin luokittelutuloksen tarkkuus esitetään prosentuaalisena osuutena tavoiteryhmittelystä maksimietäisyyden funktiona. Työssä osoitetaan, miten etäisyysattribuutiksi valittu Hamming-etäisyys ei sovellu tämän datan luokitteluun. Työn lopussa ehdotetaan menetelmää ja työkalua, joiden avulla useampaa eri lajittelija-algoritmia voidaan testata nopealla kehityssyklillä.