Lattice-Based Zero Knowledge

Vi presenterer 3 protokoller som benytter seg av lattice-basert zero-knowledge. Disse protokollene baserer sin sikkerhet på at det er vanskelig å løse det tilnærmede korteste vektor problemet, og kort heltallsløsning problemet. Den første protokollen er en identifikasjonsprotokoll, der vi overbeviser en mottaker om at vi kjenner til en spesifikk hemmelig nøkkel s. Den andre protokollen får vi ved å bruke en Fiat-Shamir transformasjon på den første protokollen, og får da en zero-knowledge protokoll uten interaksjon mellom sender og mottaker. Den siste protokollen er et argument of knowledge for å kjenne inputs som tilfredsstiller en aritmetisk krets. Vi presenterer også diverse teori som er nødvendig for at disse protokollene skal virke, og eksempler som illustrerer hva vi prøver å oppnå i noen av de mer kompliserte delene av konstruksjonene.We present 3 schemes using lattice-based zero-knowledge, using the difficulty of the Approximate Shortest Vector Problem and the Short Integer Solution Problem. The first scheme is an identification scheme, proving knowledge of a secret key s. The second scheme is a signature scheme obtained by applying the Fiat-Shamir transform on the identification scheme to create a non-interactive zero-knowledge scheme. The last scheme is an argument of knowledge for the satisfiability of an arithmetic circuit. We also present various theory necessary for these algorithms to work, as well as examples illustrating what we are trying to accomplish in some of the more complicated parts of the constructions

Self-regulating oil based heat storage

This paper has investigated the possibility of storing excess energy from solar systems as heat, using sunflower oil as the heat storage medium and heat transfer fluid. Three subsystems were designed to heat, store and utilise the hot oil for cooking purposes. The system was primarily aimed for use in developing countries. Also, it was examined if the system could be built locally and if it would be useful. As resources and equipment may be scarce in many of these countries, it was desirable to make the system as simple and robust as possible. This paper covers the subsystems for heating and cooking, while the storage system was covered in a separate paper. A self-regulating heating system was designed to heat the sunflower oil. It was shown that the heating system could be gravity-driven by utilising the density differences that occur when sunflower oil heated. A requirement for the storage to be successful was that it had to be filled with oil at a constant temperature. This was achieved by maintaining a certain oil level in the heating system. The heated oil was directed into the storage once it had expanded by the desired amount. A custom made fill valve controlled the inlet flow and the oil level in the heating system. The fill valve was designed based on results from previous work. Two cooking applications intended for frying were designed and produced. The purpose of the first design was to create a simple application that could be produced using basic workshop tools. This criterion was met with an idea of acquiring frying pans of different dimensions and welding them together. Hot oil filled the middle pan, and a smaller one was lowered into it and was used for cooking. A third and larger pan collected the residual oil. The second application was designed for cooking the traditional Ethiopian flatbread, injera. Therefore, it was inspired by griddles that are commonly used for this purpose. The application was made from aluminium because of its high thermal conductivity. Heat was transferred to the griddle by letting hot sunflower oil flow through a spiral-shaped channel, which was created using a CNC machine. Besides the inlet and the outlet, this application is completely closed, and thus it is safer to use than the other design. It has been shown that it is possible to create a self-regulating heating system which is simple and robust, purely driven by gravitational forces. Tests showed that the output temperature could be kept within a 15\degree C range for nearly three hours, where the highest temperature was 263\degree C. A field trip to Uganda showed that it was possible to produce this system using local materials and machinery. The cooking applications were only partly successful, but the second design was promising. It was shown that the entire griddle could be kept at a temperature of above 110\degree C for nearly 30 minutes, which is the temperature required to cook injera. The feedback from a local Ethiopian was that the design had great potential. With a few modifications, it would be accepted by local communities and be a useful device

Positive Youth Development and Mental Well-Being in Late Adolescence: The Role of Body Appreciation. Findings From a Prospective Study in Norway

Although a vulnerable period, adolescence is a time of great potential for healthy development. Understanding factors that contribute to mental well-being in this period is of great importance to facilitate for healthy development. During the adolescence period the body goes through rapid and considerable changes, and the focus on body appearance and perfection is substantial at societal, media, and peer level. In this study, we investigated the association between dimensions characterizing positive youth development, and mental well-being among Norwegian adolescents 16–17 years 1 year later, and whether this association was mediated by degree of body appreciation. We further tested whether the indirect and direct paths between positive youth development dimensions and mental well-being were moderated by gender. We used data from the first and second follow-up of the control arm of the COMPLETE study, a cluster randomized controlled trial in upper secondary schools in Norway. Findings showed that positive youth development in grade 1, as measured by both a combined global PYD and the dimensions competence, and connection were significantly associated with mental well-being in grade 2 in models adjusted for mental well-being in grade 1, gender and perceived family affluence. Also, body appreciation in grade 1 significantly predicted mental well-being in grade 2 in models including each of global PYD, competence, connection, character, and caring dimensions. Contrary to our hypothesis, no mediating effects of body appreciation were observed, and no moderation of indirect effects by gender were observed.publishedVersio

A Fourteen Year Follow-Up Study of Health Promoting Schools in Norway: Principals` Perceptions of Conditions Influencing Sustainability

In this study, we examined the sustainability of health-promoting practices in Norwegian schools that were enrolled in the European Network of Health-Promoting Schools from 1993 to 2003. The research questions were: How do the principals perceive that health-promoting practices have been sustained in the schools following the schools' membership of the health-promoting schools network? In what way is school leadership related to the sustainability of health promotion? The study draws on qualitative data consisting of interviews with seven principals in 2008 and school documents. The schools determined their own priorities for action based on assessment of needs in 1994. After 14 years, health promotion practices were sustained in six of the seven schools. Two factors emerged as vital for sustained health promotion practices: the health-promoting school experience and the maintenance and development of practice. The health-promoting school experience relates to staff who internalized the potential link between health promotion practices, school satisfaction, and learning. This also emphasizes the importance of the transfer of experience in sustaining health promotion practices as the staff turned over. The maintenance of vision and practice relates to the principals' commitment to school health promotion, leadership practices that encourage health promotion practices, and external collaboration with the surrounding community in health promotion.publishedVersio

Preventing Loneliness and Reducing Dropout: Results from the COMPLETE Intervention Study in Upper Secondary Schools in Norway

This study examines the impact of interventions aimed at improving psychosocial health on students’ perception of a caring school climate, their feelings of loneliness, and school completion in Norwegian upper secondary education. Two intervention conditions were tested: a universal single-tier intervention focused on improving the psychosocial school climate: the Dream School Program, and a multi-tier intervention combining the Dream School Program with a targeted measure, the Mental Health Support Team. The direct and indirect effects of these interventions on school completion were analyzed using structural equation models (SEM), with data from 1508 students (mean age at Time 1: 17.02 (SD = 0.92); 60.7% girls; 72.1% Norwegian-born). The results indicated that loneliness levels did not differ significantly between the intervention conditions. However, students in the multi-tier intervention group reported a significantly higher perception of a caring school climate compared to those in the single-tier intervention group. The multi-tier intervention group had a lower rate of school completion compared to the control group and the single-tier intervention group. The SEM analysis revealed that the multi-tier intervention reduced loneliness in the second year of upper secondary school by promoting a caring school climate in the first school year. In contrast, the single-tier intervention was associated with increased loneliness due to a decrease in the perception of a caring school climate. The implications of these findings are discussed.publishedVersio

Positive Youth Development in Norwegian Upper Secondary: The Impact of Sex, Socio-economic Status, and Immigrant Background on the Developmental Trajectories of Academic Initiative, Academic Self-efficacy, and Grade Point Average

The positive youth development (PYD) and social justice perspectives assume that it is important to consider challenges related to equity and inequality in education to understand academic processes and outcomes of the increasingly diverse student population. Students’ socioeconomic status, parents’ educational level, sex, and immigrant background impact on students’ motivation, learning, grades, and development. Norway is considered to have robust conditions for PYD and fair allocation of resources because of the country’s active and supportive welfare state model. Equity, equal opportunities, and inclusion are consistently cited as the goal of schooling in the country. This chapter investigates how sex, socioeconomic status, and immigrant background relate to the developmental trajectories of academic initiative, academic self-efficacy, and grade point average (GPA) throughout upper secondary education in Norway. The authors used data from 1508 general education students attending 16 schools that participated in the COMPLETE study, a randomised controlled trial aimed to improve the psychosocial environment in upper secondary schools and decrease dropout rates. Results from latent growth curve modelling indicated group differences related to changes over a three year-period (2016–2019) in GPA, but not in academic initiative or self-efficacy. Girls reported greater improvement in GPA than boys, students with a high socioeconomic status had a larger improvement in their GPA than students with a low socioeconomic status, and Norwegian immigrant youth experienced a greater improvement in their GPA compared to their non-immigrant peers. Findings are discussed considering school as a socially equalising actor.publishedVersio

Lessons Learned from an Intersectoral Collaboration between the Public Sector, NGOs, and Sports Clubs to Meet the Needs of Vulnerable Youths

The Norwegian Government emphasizes intersectoral collaboration to achieve health goals such as reducing social health differences. However, research shows that achieving fruitful collaboration between different organizations and the public sector is challenging. The sports sector is one potential partner for such collaboration. Although the Government calls for intersectoral collaboration that includes the sports sector, there are few concrete guidelines for how this may be implemented in practice. Guided by The Bergen Model of Collaborative Functioning, the purpose of this study was to explore factors that promote or inhibit collaboration in an intersectoral project involving the sports sector, NGOs, and public sector. The current project aimed to work towards creating health promoting activities aimed at vulnerable youths. Methods: A qualitative case study of the Sports Project with interviews of eleven collaborative partners. Results: Factors promoting collaboration amongst the different partners were having a common mission, an appreciation of the partners’ complementary skills and knowledge, and a consistent user perspective. Conclusions: By orienting the collaboration towards the users’ needs, the partners have succeeded in creating tailored health-promoting activities for vulnerable youths. However, a challenge remains in transforming the collaborative project into a sustainable structure.publishedVersio

Academic Stress, Academic Self-efficacy, and Psychological Distress: A Moderated Mediation of Within-person Effects

Previous research has largely failed to separate the between- and within-person effects in the longitudinal associations between academic stress, academic self-efficacy, and psychological distress (symptoms of anxiety and depression). Filling this research gap, this study investigated if academic self-efficacy mediated the relationship between academic stress and psychological distress at the intraindividual level during 3 years of upper secondary school. Gender moderation was also examined in the hypothesised model. The present sample consisted of 1508 Norwegian adolescents (baseline M age = 16.42; 52.9% high perceived family wealth; 70.6% Norwegian-born). The random intercept cross-lagged panel model results indicated (1) positive and time-invariant direct effects from academic stress to psychological distress, (2) academic self-efficacy partially mediated these effects, and (3) psychological distress impacted later academic stress. Academic stress was more strongly related to academic self-efficacy and psychological distress at the interpersonal level for boys, while the intraindividual impact of academic stress on psychological distress was stronger for girls. The study findings might have implications for school-based implementation strategies and theoretical development.publishedVersio

Hello Darkness, My Old Friend: Moderating a Random Intercept Cross-lagged Panel Model of Loneliness and Symptoms of Anxiety and Depression

The present study investigated the trait- and state-like associations between loneliness and symptoms of anxiety and depression during three years in middle to late adolescence. The moderating effect of gender and social self-efficacy was examined on the hypothesised model. The sample consisted of 1508 Norwegian upper secondary school students (61% female; mean age at T1 = 16.33; 52.9% high socioeconomic position; 70.6% Norwegian-born). We found 1) strong and positive trait- and state-like associations between loneliness and symptoms of anxiety and depression, 2) that anxiety and depressive symptoms consistently predicted later loneliness but not the other way around, 3) that gender moderated parts of the state-like associations between loneliness and symptoms of anxiety and depression, and 4) that social self-efficacy had no moderating effect on the longitudinal relationship between loneliness and anxiety and depressive symptoms. The present study might inform future research, theory development, and intervention strategies in middle to late adolescent samples.publishedVersio

Mental well-being among students in Norwegian upper secondary schools: the role of teacher support and class belonging

Knowledge about factors in school that can promote adolescents’ mental health is of great value for national health policies and health promotion work. This cross-sectional study investigated levels of mental wellbeing measured with the Warwick-Edinburgh Mental Well-being Scale and the relationship with teacher support and class belonging among 574 Norwegian high school students, aged 16-17 (55.1% boys). The data stem from the COMPLETE-project. Results showed that students reported an average mental wellbeing of 3.50 (SD 0.88, range 1-5), with significant differences across gender, study specialization area and socioeconomic status groups. Class belonging partially mediated the observed relationship between teacher support and mental well-being after adjusting for covariates. The findings indicate that a supportive teacher may be a significant factor for both students’ class belonging and mental well-being, and suggests that school policies and programs should include a focus on promoting teachers’ supportive behavior.publishedVersio