Modelling and Analysis of Floating Bridge Concepts Exposed to Environmental Loads and Ship Collision

The need for improving the infrastructure in Norway meets challenges when developing solutions to cross the wide and deep fjords along the coastline. The Norwegian Public Roads Administration (NPRA) is behind the ongoing project "The Ferry Free Coastal Route E39" where by replacing seven ferry crossings with floating bridges and submerged tunnels, today s travel- and transportation time between Kristiansand and Trondheim will be reduced from 21 to 11 hours. The fjords to be crossed are wide and deep with water depths up to 1300 meters. The project has faced major economic and technological challenges related to the solutions when advanced offshore technology and existing bridge solutions have been combined to establish concepts that satisfy the design criteria. This has lead to an increase in product cost from 150 to 340 billion NOK. The future project progress will depend on economic constraints and development of future technological solutions. This thesis carries out a concept study of a floating bridge concept for crossing the Halsafjord along E39. The planned distance reaches 2.1 km from Halsneset to Urdneset. The concept is based on the proposed curved bridge for crossing the 4 km long Bjørnafjord. The thesis is carried out for the NPRA with the long-term goal of reduced response at lower costs than presented for the Ferry Free Coastal Route E39 project up until today. Two concepts are analysed, where a curved bridge girder is supported by the undercarriage of offshore jackets, cable stay bridges and floating pontoons. Concept 1, I-jacket: Curved bridge supported by one steel jacket placed 400 m from the east abudment. The span between the abudment and jacket is given additional support from cable stays. The remaining bridge girder is supported by nine floating pontoons. Concept 2, II-jacket: Curved bridge supported by two steel jackets, each placed 400 m from the east and west abudments. The span between the jackets and the shoreline is given additional support from cable stays. The bridge girder between the jackets is supported by six floating pontoons. The concepts are modeled in the finite element software ANSYS Mechanical APDL 18.2. Properties to represent global mass and stiffness properties of the jacket are obtained from analyses using the USFOS software and implemented in the ANSYS model. Response from a static analysis during environmental loading conditions including wind, current and tidal variation is measured for both concepts. A regular wave analysis is performed on the II-jacket bridge for characteristic waves in the relevant area, as this concept indicated more careful considerations regarding dynamics. The static and regular wave analysis show that the response is within the design criteria limits, except for a small exceedance in vertical deflection during low tide, and a small exceedance for the acceleration component during wave conditions with a 1 year return period. Neither of the concepts exhibit critical response in terms of moments or stresses, but cyclic loading and fatigue should be assessed in further work. Considering the exceeded criteria and modeling approach, redesign and further work on hydrodynamics will be necessary. A modal analysis shows that the first natural periods range from 82 seconds and lower (I-Jacket) and 54.5 seconds and lower (II-Jacket). Swell generated waves with 1, 100 and 10 000 year return periods overlap when the wave period is between 6 and 18 seconds for both concepts. For local wind generated sea, lower modes coincide. The first dynamic modes indicate that low frequency induced dynamic response will be important to assess as this indicates chance of resonant response. A ship collision scenario is modeled in USFOS to measure the jackets response when exposed a collision with a RORO-vessel of similar mass and velocity as those that operate in the Halsafjord. The collision energy is 209 MJ. Results from the ship collision analysis indicate that jacket suffers severe damage, which may cause critical damage to the bridge. A full dynamic analysis of ship collision with a global bridge model must be performed to substantiate whether the bridge will survive or collapse in case of a collision. The analyses performed in this thesis are insufficient to verify that the concept is feasible, but gives an indication of the global static and dynamic behavior of the structure as well as highlighting of further work

Timing and time synchronization within LiDAR- and IMU-based simultaneous localization and mapping (SLAM)

Denne avhandlingen presenterer konstruksjonen av en sensorsammensetning bestående av en Ouster16 LiDAR, en STIM300 inertial måleenhet (IMU) og tre f9p u-blox globalt navigasjonssatellittsystem (GNSS)-mottakere, og undersøker ytelsen til en spesifikk LiDAR-inertial Samtidig posisjonering og kartlegging (SLAM) algoritme, Liorf, når ulike tidsstemplingsteknikker brukes for sensor-synkronisering. Hittil har forskningsfeltet innen anvendt sensorfusjon ikke omfattende studert hvordan nøyaktigheten av synkroniseringen mellom sensormålinger påvirker ytelsen til ulike SLAM-algoritmer. De benyttede teknikkene i denne avhandlingen er basert på maskinvarebasert tidsstempling fra et SentiBoard og programvarebasert tidsstempling basert på Robotic Operating System (ROS). En synkroniseringsmodul for å synkronisere en Ouster LiDAR, basert på enkodersignaler, med et SentiBoard gjennom dens ROS-driver, blir presentert. Data samles inn ved å montere sensorsammensetningen på toppen av en bil og kjøre i byområder og på motorveien. Posisjons- og orienteringsestimatene fra Liorf blir sammenlignet med estimatene som er oppnådd gjennom en sanntidskinematisk posisjonering (RTK) basert på GNSS-målinger. Fullstendige orienteringsestimat basert på RTK GNSS oppnås ved bruk av tre GNSS-mottakere. Resultatene indikerer at det ikke er noen betydelig forskjell mellom maskinvare- og programvaresynkronisering når det gjelder nøyaktigheten av estimatene fra Liorf. Imidlertid er nøyaktigheten av programvaresynkronisering sterkt avhengig av den anvendte programvaren og maskinvarekomponentene. Eksperimentet som ble utført i denne avhandlingen brukte høykvalitetssensorer, datamaskiner og programvare, noe som resulterte i nøyaktige programvaretidsstempler som ikke nødvendigvis vil være mulig i andre systemer. I tillegg til synkroniseringsanalysen av Liorf blir det presentert en forbedret tilnærming for å integrere GNSS-målinger i algoritmen. Denne modifikasjonen innebærer kompensering for den relative monteringen mellom IMU-en og GNSS-antennene, samt innlemming av relative posisjonsmålinger når flere antenner brukes. Implementeringen av denne modifikasjonen krevede utviklingen av to nye klasser innenfor Georgia Tech Smoothing and Mapping (GTSAM) C++ biblioteket.This thesis presents the construction of a sensor payload consisting of an Ouster16 LiDAR, a STIM300 inertial measurement unit (IMU), and three f9p u-blox global navigation satellite systems (GNSS) receivers, and investigates the performance of a particular LiDAR-inertial simultaneous localization and mapping (SLAM) algorithm, Liorf, when different timestamping primitives are used for sensor synchronization. To date, the field of applied sensor fusion has not extensively studied how the accuracy of synchronization between sensor measurements affects the performance of various SLAM algorithms. The primitives used are based on hardware timestamping from a SentiBoard, and software timestamping based on the Robotic Operating System (ROS). A synchronization module for synchronizing the Ouster LiDAR, based on encoder pulses, with the SentiBoard through its ROS driver is presented. Data is collected by mounting the sensor payload on top of a car and driving in urban areas as well as on the highway. The position and orientation estimates from Liorf are compared to estimates obtained by a Real-time kinematic positioning (RTK) solution from GNSS measurements. Full orientation estimates based on RTK GNSS are achieved through the use of three GNSS receivers. The result indicates that there is no significant difference between hardware and software synchronization when it comes to Liorf pose estimation accuracy. However, the accuracy of software synchronization is highly dependent on the deployed software, and the hardware components the software is running on. The experiment performed in this thesis used high-quality sensors, computers, and software, which resulted in accurate software timestamps, that would not necessarily be possible in other systems with low-quality components. In addition to the synchronization analysis of Liorf, an enhanced approach for integrating GNSS measurements into the algorithm is presented. This modification involves compensating for the relative mounting between the IMU and the GNSS antennas, as well as incorporating relative position measurements when multiple antennas are used. The implementation of this modification required the development of two new classes within the Georgia Tech Smoothing and Mapping (GTSAM) C++ library

Exploring The Possibilities of Investing in Artificial Intelligence : A comprehensive analysis of NQROBO index performance

This thesis investigates the potential of beating the market index for an investor by investing in Artificial Intelligence (AI). We have analysed the performance of Nasdaq CTA Artificial Intelligence & Robotics (NQROBO) from January 2018 to August 2023, comparing it to the Nasdaq Composite (NASDAQ) and S&P 500. We have simulated the behaviour of an openminded investor who uses simple prediction models to forecast returns. We have tried to make this simulation as realistic as possible using minimal hindsight. Our thesis is based on three analyses: a historical analysis evaluating NQROBO’s performance, a pseudo-out-of-sample forecasting performance analysis exploring how an investor in real time utilising a forecasting tool would perform, and lastly, an optimal relative weighting analysis of NQROBO, based on the pseudo-out-of-sample analysis. The historical analysis revealed that NQROBO outperformed the market from 2020 through 2022. It also uncovered that the Alpha was primarily positive from 2020 to early 2022, before turning negative in 2022. The Beta was lower than the market until 2022 before increasing sharply and stabilising at 1,1. Regarding the Fama French Factors, we identified the market as a consistent driver for returns. HML, RMW and CMA fluctuating greatly, being mostly negative, suggesting that NQROBO performs best when the market favours growth-oriented firms with an aggressive investment strategy. Indicating that the index has the potential of outperforming the market over certain periods if the market conditions are favourable. Furthermore, the pseudo-out-of-sample forecasting performance analysis showed that portfolios utilising Sharpe Ratio, RMSE and Hybrid RMSE weighting could outperform the market, if rebalancing daily. Suggesting that potential gains of investing in NQROBO is short lived. Lastly, our optimal relative weighting analysis of NQROBO’s shows that a highly dynamic weight allocation that is rebalanced frequently is beneficial. Enabling the portfolio to capture short-term gains and beating the market index over the period. The findings suggest that investing in AI offer the potential of beating the market index if done flexibly.nhhma

Human factor influences on supervisory control of remotely operated and autonomous vessels

Autonomous ships require remote supervision from a human operator to ensure safety. However, there are knowledge gaps concerning human factor influences on remote supervisory control. We investigate the influence of five factors on remote supervisory control during simulated intervention scenarios: (i) Skillset, represented by gamers and navigators; (ii) Monitoring Time, represented by either 5 or 30 min of passive monitoring; (iii) Number of Vessels, represented by either one or three vessels; (iv) Available Time, represented by 20- or 60-s critical time windows; (v) Decision Support System (DSS), represented by availability of a DSS. The experiment was a randomized factorial design where participants (n = 32) completed two interventions: first a handover (automation detects a critical event and hands over control) and then a takeover (operator detects a critical event and takes over control). We observed: (i) gamers and navigators both demonstrated transferrable skillsets, but neither group excelled over the other; (ii) monitoring time affected boredom, but this translated to minor performance effects. Moreover, performance was reduced under conditions of (iii) supervising three vessels, (iv) low time availability, and (v) unavailable DSS. These outcomes contribute to the empirical basis for assessing maritime human factors in remotely controlled and autonomous ship design.publishedVersio

Modelling and Analysis of Floating Bridge Concepts Exposed to Environmental Loads and Ship Collision

The need for improving the infrastructure in Norway meets challenges when developing solutions to cross the wide and deep fjords along the coastline. The Norwegian Public Roads Administration (NPRA) is behind the ongoing project "The Ferry Free Coastal Route E39" where by replacing seven ferry crossings with floating bridges and submerged tunnels, today s travel- and transportation time between Kristiansand and Trondheim will be reduced from 21 to 11 hours. The fjords to be crossed are wide and deep with water depths up to 1300 meters. The project has faced major economic and technological challenges related to the solutions when advanced offshore technology and existing bridge solutions have been combined to establish concepts that satisfy the design criteria. This has lead to an increase in product cost from 150 to 340 billion NOK. The future project progress will depend on economic constraints and development of future technological solutions. This thesis carries out a concept study of a floating bridge concept for crossing the Halsafjord along E39. The planned distance reaches 2.1 km from Halsneset to Urdneset. The concept is based on the proposed curved bridge for crossing the 4 km long Bjørnafjord. The thesis is carried out for the NPRA with the long-term goal of reduced response at lower costs than presented for the Ferry Free Coastal Route E39 project up until today. Two concepts are analysed, where a curved bridge girder is supported by the undercarriage of offshore jackets, cable stay bridges and floating pontoons. Concept 1, I-jacket: Curved bridge supported by one steel jacket placed 400 m from the east abudment. The span between the abudment and jacket is given additional support from cable stays. The remaining bridge girder is supported by nine floating pontoons. Concept 2, II-jacket: Curved bridge supported by two steel jackets, each placed 400 m from the east and west abudments. The span between the jackets and the shoreline is given additional support from cable stays. The bridge girder between the jackets is supported by six floating pontoons. The concepts are modeled in the finite element software ANSYS Mechanical APDL 18.2. Properties to represent global mass and stiffness properties of the jacket are obtained from analyses using the USFOS software and implemented in the ANSYS model. Response from a static analysis during environmental loading conditions including wind, current and tidal variation is measured for both concepts. A regular wave analysis is performed on the II-jacket bridge for characteristic waves in the relevant area, as this concept indicated more careful considerations regarding dynamics. The static and regular wave analysis show that the response is within the design criteria limits, except for a small exceedance in vertical deflection during low tide, and a small exceedance for the acceleration component during wave conditions with a 1 year return period. Neither of the concepts exhibit critical response in terms of moments or stresses, but cyclic loading and fatigue should be assessed in further work. Considering the exceeded criteria and modeling approach, redesign and further work on hydrodynamics will be necessary. A modal analysis shows that the first natural periods range from 82 seconds and lower (I-Jacket) and 54.5 seconds and lower (II-Jacket). Swell generated waves with 1, 100 and 10 000 year return periods overlap when the wave period is between 6 and 18 seconds for both concepts. For local wind generated sea, lower modes coincide. The first dynamic modes indicate that low frequency induced dynamic response will be important to assess as this indicates chance of resonant response. A ship collision scenario is modeled in USFOS to measure the jackets response when exposed a collision with a RORO-vessel of similar mass and velocity as those that operate in the Halsafjord. The collision energy is 209 MJ. Results from the ship collision analysis indicate that jacket suffers severe damage, which may cause critical damage to the bridge. A full dynamic analysis of ship collision with a global bridge model must be performed to substantiate whether the bridge will survive or collapse in case of a collision. The analyses performed in this thesis are insufficient to verify that the concept is feasible, but gives an indication of the global static and dynamic behavior of the structure as well as highlighting of further work