Sanna Heikkinen

Learn More
The air interface of the UMTS Terrestrial Radio Access (UTRA) covers both a frequency division duplex (FDD) part for the paired bands and a time division duplex (TDD) part for the unpaired bands of the UMTS spectrum. Universal Mobile Telecommunication System (UMTS) is the 3rd-generation mobile communication system. This paper presents an interference(More)
INTRODUCTION Role of hair dyes in the etiology of breast cancer has occasionally raised concern but previous research has concluded with mixed results. Remnants of prohibited aromatic amines have been found in many hair dye products, and elevated levels of DNA-adducts of these amines have been detected from breast epithelial cells of hair dye users.(More)
IT companies worldwide have started to improve their service management processes based on best practice frameworks, such as IT Infrastructure Library (ITIL). However, many of these companies face difficulties in demonstrating the positive outcomes of IT service management (ITSM) process improvement. This has led us to investigate the research problem: What(More)
Main aim was to estimate the association between use of exogenous hormones and breast cancer (BC) risk in a large population-based survey, and to assess the representativeness and overall validity of the data. The survey ‘Women’s Health and Use of Hormones’ was conducted in Finland in 2009, including 7,000 BC cases and 20,000 matched population controls.(More)
Continual service improvement within IT service management is an important research topic. Nowadays, IT services should be actively developed and improved in order to increase quality and cost effectiveness. Continual Service Improvement enables identification of bottlenecks and weak areas in the services. The research problem of this study is: what types(More)
BACKGROUND The Finnish Cancer Registry (FCR) has collected population-based data on cancer incidence for scientific research and statistical purposes since 1953. Our aim was to provide a comprehensive quality assessment of the current cancer registry data in Finland. METHODS We used established quantitative and semi-quantitative techniques to address four(More)
BACKGROUND In Finland, organized nationwide breast cancer (BC) screening is biennially offered for women aged 50-69 years. The aim was to estimate, for the first time in Finland, the proportion of women having opportunistic mammography at age less than 50 years and to investigate the role of BC family history and educational level for having opportunistic(More)
The purpose of this study was to analyze the factors affecting motivation and whether these factors support students’ autonomy. Students were interviewed in order to study the impact of collaborative learning study arrangements on the their motivation. The data was then analyzed using selfdetermination theory. The study showed that it is possible to build(More)