Regional gray matter volumetric changes in autism associated with social and repetitive behavior symptoms.

BackgroundAlthough differences in brain anatomy in autism have been difficult to replicate using manual tracing methods, automated whole brain analyses have begun to find consistent differences in regions of the brain associated with the social cognitive processes that are often impaired in autism. We attempted to replicate these whole brain studies and to correlate regional volume changes with several autism symptom measures.MethodsWe performed MRI scans on 24 individuals diagnosed with DSM-IV autistic disorder and compared those to scans from 23 healthy comparison subjects matched on age. All participants were male. Whole brain, voxel-wise analyses of regional gray matter volume were conducted using voxel-based morphometry (VBM).ResultsControlling for age and total gray matter volume, the volumes of the medial frontal gyri, left pre-central gyrus, right post-central gyrus, right fusiform gyrus, caudate nuclei and the left hippocampus were larger in the autism group relative to controls. Regions exhibiting smaller volumes in the autism group were observed exclusively in the cerebellum. Significant partial correlations were found between the volumes of the caudate nuclei, multiple frontal and temporal regions, the cerebellum and a measure of repetitive behaviors, controlling for total gray matter volume. Social and communication deficits in autism were also associated with caudate, cerebellar, and precuneus volumes, as well as with frontal and temporal lobe regional volumes.ConclusionGray matter enlargement was observed in areas that have been functionally identified as important in social-cognitive processes, such as the medial frontal gyri, sensorimotor cortex and middle temporal gyrus. Additionally, we have shown that VBM is sensitive to associations between social and repetitive behaviors and regional brain volumes in autism

Distal Biceps Brachii Tendon Transfer for Re-establishing Extrinsic Finger Function: Feasibility Study in Cadavers

Purpose To determine the anatomic feasibility of transferring the biceps brachii tendon into either the extensor digitorum communis (EDC) or flexor digitorum profundus (FDP), determine the excursion imparted to EDC and FDP tendons after transfer, and compare the work capacity of the cadaver biceps to previously published data on the biceps as well as the recipient muscles by calculating the physiologic cross-sectional area (PCSA). Methods Four fresh-frozen cadaver shoulder-elbow-wrist specimens were used to measure tendon excursion that can be obtained with transfer of the distal biceps tendon into either the EDC or FDP. Two cadavers had distal biceps-to-EDC transfer performed, and the other 2 had distal biceps-to-FDP performed. Passive ranging of each elbow from flexion to extension and active loading at 90° of elbow flexion were then performed on each specimen to determine tendon excursion. An analysis of the PCSA of the biceps muscle was performed on each specimen. Results Distal biceps-to-EDC transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. Distal biceps-to-FDP transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. The average PCSA was 3.6 cm2. Conclusions Transfer of the distal biceps tendon into the EDC or FDP is anatomically feasible and provides roughly 24 mm of tendon excursion to the tendon units. The PCSA in the specimens used is slightly lower than other published data; it closely approximates the PCSA of the EDC, but is only half of the PCSA of the FDP in previously published data

BlockDiploma – Decentralizing the Norwegian Diploma Registry using Blockchain Technology

Academic diplomas are being falsified and potentially resulting in unqualified individuals getting the job, or a better candidate being bypassed by a forger. Secure and reliable verification mechanisms for academic diplomas are needed. Norway has attempted to accomplish this by developing the Diploma registry, a digital solution for sharing academic results. Our research reviews current diploma systems to identify challenges. Following the review, our research effort shifts focus from identifying challenges to attempting to find solutions using blockchain technology. The research is based on the hypothesis that there are challenges with the present solutions, and that those challenges can be resolved by decentralizing the diploma registry using blockchain and peer-to-peer technology. The research is classified as computer research using the engineering method. The first step was to gather and aggregate information about current diploma systems and relevant blockchain proposed solutions. Based upon the information gathered we could identify challenges with the current solutions, and we started to formulate requirements for a blockchain-based one. After formulating our proposal in the form of written requirements, we started to explore how the challenges could be resolved using decentralized technology. Following the exploration of decentralized technologies, we ended up with developing a decentralized application called BlockDiploma. BlockDiploma is built using smart contracts with the Ethereum blockchain, IPFS for decentralized storage and standard web technologies for the user interface. During and after the development we analyzed and evaluated how well it resolved the identified challenges and whether it introduces new challenges. Our conclusion is that there are several issues other than just falsification with the present diploma systems, and that a decentralized diploma registry can in the future be part of the solution to those challenges.Masteroppgave i informatikkINF399MAMN-PROGMAMN-IN

Battery energy storage system connected to a three-phase 50 Hz-grid

Battery energy storage systems (BESS) employing secondary battery technology may offer the greatest potential for large-scale integration of renewable energy sources (RES), and is considered a key element for enabling smart grids for future power systems. The two main components of a BESS are the power conversion system (PCS) and the battery management system (BMS). When selecting a PCS topology, the most important characteristic are the reliability and efficiency of the converter. The converter technologies commonly used for PCS have been the conventional two- and three-level voltage source converters (VSCs), however the PCS topology chosen for the BESS in this thesis is the modular multilevel converter (MMC). The MMC offers several advantages over the conventional VSCs, such as modularity and scalability, low total harmonic distortion (THD), excellent efficiency and reliability. The battery technology chosen for the BESS is based on the lithium-ion battery technology. Lithium-ion offers desirable characteristics such as high efficiency, good response time, reasonably high charge and discharge rates, small dimensions and/or low weight and little maintenance requirements. All of the abovementioned converter and battery characteristics imply that the full MMC-BESS scheme will become highly efficient and reliable with a high round trip efficiency, well-suited for large-scale BESS applications. The system in which the MMC-BESS is investigated, comprises of an offshore wind farm, a two-level VSC-based HVDC transmission system and the AC grid on land. Based on the investigated cases, this thesis can be divided into two main parts: design of the MMC-BESS, and modeling and simulation of the MMC-BESS. The design-part is mainly focusing on a more realistic approach of the MMC-BESS configuration by performing various calculations regarding both battery and converter requirements. The initial MMC-BESS configuration was the conventional, half-bridge MMC with centralized batteries connected to the common DC-link. This approach may offer the simplest solution to implement, however it negatively affects the reliability and efficiency of the full scheme. Furthermore, to mitigate the drawbacks of the centralized battery-approach, an MMCBESS configuration based on distributed batteries was proposed. This approach utilizes the MMC modular structure, as well as improving both the reliability and efficiency. Moreover,by placing bidirectional DC-DC converters, base on the dual active bridge (DAB) topology, in the interface between the converter submodules and the batteries, a galvanic isolation of the batteries could further improve both the safety and reliability of the scheme. Finally, a proposed approach with the main purpose of reducing space, components and cost, was to replace the two-level VSC stations of the HVDC transmission system with the MMC-BESS based on distributed batteries employing DAB converters. This solution offers the possibility to also improve the performance of the HVDC system. However, more effort should be made in verifying these assumptions. The modeling and simulation-part analyzed the initially proposed MMC-BESS configuration in the design-part. The MMC was modeled as a simplified MMC, with an AC-side and DC-side representation and a power balance equation coupling the two sides together. The modeling approach was based on the scientific paper draft presented in [70], as well as the paper presented in [25]. The centralized battery was modeled according to the linear battery model with a small equivalent series resistance (ESR). A state-of-charge (SoC) measurement system was modeled as a part of the BMS, to monitor the charging and discharging processes of the centralized battery. Furthermore, the HVDC transmission system was provided by Prof. Tedeschi and Post.doc. Sanchez Acevedo at the Department of Electric Power Engineering, NTNU. Moreover, the offshore wind farm and the AC grid on land where implemented as ideal AC voltage sources. The simulation verified the MMC s ability to provide a controlled bidirectional power exchange with the centralized battery. The results showed the MMC operating satisfactorily with an active power flow in the range of 1.0 and -1.0 pu, and well-tuned current and energy controllers. The SoC measurements further verified the charging and discharging processes of the battery, where the battery SoC varied between 100% and 73% SoC. The MMC-BESS ability to provide grid support for variable wind power delivered to the AC grid was also investigated. The results showed the MMC-BESS was able to inject active power to the AC grid, as well as absorb active power from the wind farm. The SoC varied between 100% and 85% throughout the simulation. The last case to be investigated, was a comparison between the MMC-BESS presented in this thesis, where the scheme was connected to the AC-grid, and a BESS solution connected to the HVDC-link of the transmission system. The latter solution is based on the master s thesis of Marta N. Hellesnes,in [38]. Both solutions where able to support the AC grid by smoothing the varying wind power from the offshore wind farm

Modeling and Control of Trawl Systems

This thesis is motivated by the possible benefits of a more precise trawl control system with respect to both environmental impact and fishing efficiency. It considers how the control performance of a pelagic trawl system can be improved, partly by introducing a control architecture tailor-made for the trawl system subject to industrial requirements, and partly by developing a trawl door control concept. A mathematical model of the trawl system is developed, including an accurate model of the hydrodynamic forces on the trawl doors. This model estimates both the steady state and the transient forces on trawl doors moving in six degrees of freedom. The steady state hydrodynamic forces are based on wind tunnel experiments. To estimate the transient forces, a software code based on potential theory is developed. This software estimates the time-dependency of the forces from circulation about the foil, the angular damping forces, and the forces from relative accelerations between the fluid and the trawl door. Various concepts for trawl door control are evaluated. This is done both analytically, by simulations and by towing tank experiments. Based on the results, a new trawl door control concept is proposed. The trawl door control concept is developed to fulfill the demands on both energy consumption, robustness and control performance. Because of the contradictory demands on performance, stability and energy efficiency, the control concept is improved using numerical optimization. The optimization is based on timedomain simulations of the trawl system. The design of an overall trawl control architecture taking advantage of the trawl door control system is presented. This takes industrial constraints into account, such as the energy supply on the trawl doors. The control system is based on model predictive control and facilitates complex objectives, constraints and process models. The use of model predictive control is made possible by letting PID plant controllers act as a layer between the model predictive controller and the trawl system. The model predictive controller is thus able to operate on a stable and predictable system with no fast dynamics. To reduce the energy consumption of the trawl door, conventional feedback control is avoided on this part of the control system, and step wise feedforward control is instead employed. The main contributions in this work are the mathematical modeling of the hydrodynamic forces on a trawl door, the design of a control architecture tailor-made for trawl system control and the method for optimization of the trawl door control concept.dr.ing.dr.ing

Information asymmetry between banks, rent extraction, and switching in mortgage lending

This study explores how banks compete for a mortgage following different information about the same client. We employ inside information about a bank's clients and the information available to an outside bank making a competing offer for 13,080 individual mortgage clients in Norway from 2010 to 2018. We demonstrate that disentangling the effects of the duration of the client‒bank relationship and the asymmetric information between banks bridges a gap in the existing literature. The inside bank is less sensitive to negative external information and extracts rent based on the length of the client‒bank relationship.publishedVersio

Mortgage lending valuation bias under housing price changes and loan-to-value regulations

We examine valuation bias, regulatory loan-to-value limits, and real estate price fluctuations using unique data from two Norwegian banks. We investigate whether automated valuation methods significantly affect foreclosure discounts. Banks using multiple valuation methods tend to report loan-to-value bias by selecting the most optimistic value, underestimating and underreporting risk in declining property markets. This risk increases near regulatory loan-to-value limits, and the findings are robust across homogenous and heterogeneous properties. We recommend reporting automated valuation estimates for all applicable properties and disclosing the percentage of valuations done with different methods to improve transparency and risk comparability between banks.publishedVersio

What characterizes best practices for the safe and efficient execution of W2W operations in offshore wind farms?

Denne masteroppgaven undersøkte hva som karakteriserer beste praksis for sikker og effektiv gjennomføring av «Walk-to-Work» (W2W)-operasjoner i offshore vindmølleparker. Dette er en industri i vekst, der W2W-operasjoner har blitt en sentral del av service- og vedlikeholdsarbeidet. Slike operasjoner er komplekse og gjennomføres ofte under dynamiske og krevende værforhold, noe som øker risikoen for ulykker, forsinkelser og operasjonelle avvik. Studien bygget på en kvalitativ forskningsmetode. Datagrunnlaget inkluderte en fire ukers observasjonsperiode om bord på et «Service Operation Vessel» (SOV) under aktive W2W-operasjoner, samt seks semistrukturerte intervjuer med erfarne maritime fagpersoner. Materialet ble analysert tematisk for å identifisere gjentakende mønstre, operative utfordringer og kjennetegn ved gode beslutningsprosesser og operativ gjennomførelse. Resultatene viste at vellykkede W2W-operasjoner kjennetegnes av tre sammenhengende og gjensidig forsterkende prinsipper: god planlegging, dynamisk beslutningstaking og en sterk kultur for operasjonell læring. Nøkkelfaktorer inkluderte tydelig og presis kommunikasjon, effektiv koordinering mellom mannskap og prosjektpersonell, samt bruk av hensiktsmessige verktøy for risikohåndtering tilpasset den aktuelle situasjonen. Det ble også tydelig at klare ansvarsforhold og en delt oppfatning av prosedyrer mellom mannskap og prosjektpersonell bidro til å redusere operasjonell usikkerhet og styrke situasjonsforståelsen om bord. Evnen til å tilpasse operasjonen i møte med skiftende værforhold og operasjonelle begrensninger fremsto som en kritisk egenskap hos både mannskap og prosjektpersonell. Funnene kan bidra til utvikling eller revisjon av prosedyrer for W2W-operasjoner i offshore vindmølleparker, gjennom å gi grunnlag for tydeligere retningslinjer, styrket operasjonell forståelse blant involvert mannskap og forbedret koordinering mellom de ulike aktørene. Ved å dokumentere praksis fra et operativt perspektiv til sjøs, gir oppgaven også empirisk innsikt som kan være relevant for videre forskning på risikohåndtering, koordinering og gjennomføring av W2W-operasjoner.This master’s thesis examined what characterises best practice for the safe and efficient execution of Walk-to-Work (W2W) operations in offshore wind farms. As the offshore wind industry expands rapidly, W2W operations have become a vital part of service and maintenance activities. These operations are complex and often conducted in challenging and dynamic weather conditions, increasing the risk of accidents, delays, and operational deviations. A qualitative research approach was applied, combining four weeks of participatory observation onboard a Service Operation Vessel (SOV) during active W2W operations, along with six semi-structured interviews with experienced maritime personnel. The empirical data was analysed thematically to find recurring patterns, operational challenges, and enabling factors in decision-making and task execution. The findings showed that successful W2W operations were characterised by three interdependent pillars: proactive planning, adaptive decision-making, and a sustained culture of operational learning. Key characteristics included clear and timely communication, effective coordination between the marine crew and project personnel, and the use of appropriate risk management tools tailored to the operational context. Additionally, a shared understanding of roles and responsibilities, combined with procedural alignment between vessel and client personnel, was identified as important for reducing operational uncertainty and supporting overall clarity. The ability to adapt plans dynamically in response to shifting weather conditions and operational constraints appeared as a critical competence among both the marine crew and project personnel. These findings can support the development or refinement of procedures for W2W operations in offshore wind projects by informing clearer guidelines, strengthening crew understanding, and enhancing coordination across the involved personnel. By documenting practices from a first-hand maritime perspective, the thesis also offers empirical insight relevant to future research on risk management and the operational coordination and reliability of W2W operations

Developing Digital Citizenship and Civic Engagement Through Social Media Use in Nordic Schools

In this chapter, we explore the factors involved in developing digital citizenship through social media use in schools for 14-year-old students in four Nordic countries. The call for digital citizenship and digital citizenship education stems from the new and multiple ways in which young people are engaging in and communicating about civic issues through the use of social media. Schools could be considered to play a core part in developing students’ digital civic engagement, yet the field of digital citizenship education and the factors that enable engagement in schools are underexplored. To address this issue, in this chapter we have completed a mixed methods study analyzing the national curricula in the four Nordic countries and complementing this with an analysis of data from school leaders, teachers, and 14-year-old students participating in the IEA International Civic and Citizenship Education Study (ICCS) 2016. The findings of the analysis show that digital citizenship and citizenship in general are prevailing ideals in the national curricula and that schools are well-equipped technologically. Yet, both teachers and students are ambivalent in their use of social media for developing digital citizenship. Thus, we argue that digital citizenship in education is a manifold and emerging phenomenon and that students might be important guides for its further development in schools.publishedVersio