Liquefied natural gas (LNG) offers negligible NOx and SOx emissions as well as reductions in CO2 compared with other liquid hydrocarbons. LNG is a significant player in the global energy mix, with a projection of 40% increase in demand for the next two decades. It is anticipated that the expected rise in demand will cause the fleet of LNG carriers (LNGC) to expand. This work concentrates on steam-powered LNGC, which accounted for 47% of the LNGC fleet in 2018. It performs an empirical analysis of continuous monitoring data that provide high levels of accuracy and transparency. The analysis is done on data collected from 40 LNGCs for over a year to estimate the fleet's operational profile, fuel mix and energy performance. The findings of this work are relevant for bottom-up analysis and simulation models that depend on technical assumptions, but also for emission studies such as the upcoming Fourth International Maritime Organization Greenhouse Gases study.

The objective of this research was to investigate the factors of assessment that students undergoing authentic assessment perceived to be significant regarding their academic achievement. This project advanced past research by the authors which found that the academic achievement of seafarer students was significantly higher in a formatively implemented authentic assessment compared with a summative traditional assessment. The academic achievement (assessment scores) was based on the students’ performance in analysing information presented in a real-world context (authentic assessment) as opposed to the analysis of information presented devoid of a real-world context (traditional assessment). Using the data obtained from students undergoing the authentic assessment, this project correlated their perceptions of authenticity for factors of assessment to their scores in the associated task. Stage 1 focused on deriving the factors conceptually from the definition of the authentic assessment by the authors, based on which a perception survey questionnaire was designed. Stage 2 extracted new factors through a factor analysis conducted using the software SPSS. Both stages of investigation found that the factor of transparency of criteria was a significant predictor of the students’ academic achievement.

Colour is widely utilised as a visual coding system in visual search, but its application under vibration conditions (e.g., in various vehicles) has not been fully explored. This study was designed to examine the effect of colour combinations on performance of visual search tasks conducted in vibration conditions. Forty-eight university students participated in an experiment where they were required to identify target type and location under 24 colour combinations (half in negative polarity and half in positive polarity) and three vibration conditions (static, low, and high). The findings showed that vibration did not significantly affect performance, perceptions, or physiological aspects. Colour combination significantly affected response time, and the participants preferred colour combinations that had the potential to produce better performance. Colour combinations with negative polarity (e.g., yellow on black and white on black) are recommended for presenting search interfaces. These findings are of importance in human–computer interface designs for information display under vibration conditions.

The year 2020 marked the 95th anniversary of Francesco De Pinedo and Ernesto Campanelli's record-breaking flight of 55,000 km, from Italy to Australia, Japan and back, in a seaplane named Gennariello. Their achievement was lauded worldwide, especially in Australia, where the press reported on it intensively. This paper reconstructs the story of the flight by analysing the Australian press accounts and De Pinedo's diary, to understand how the Australian public perceived the event. It investigates the aviators’ arrival in Perth, Adelaide and Melbourne, where their popularity was greatest and where the local Italian communities enthusiastically welcomed them. The analysis shows that the flight engendered increased public interest and paid dividends in terms of image for the commercial companies involved, while fascism exploited it to display its progress in aviation. The paper concludes by exploring the legacy of the endeavour in modern Italy and Australia, emphasising the differences between the countries.

Visual–Inertial Navigation Systems (VINS) plays an important role in many navigation applications. In order to improve the performance of VINS, a new visual/inertial integrated navigation method, named Sliding-Window Factor Graph optimised algorithm with Dynamic prior information (DSWFG), is proposed. To bound computational complexity, the algorithm limits the scale of data operations through sliding windows, and constructs the states to be optimised in the window with factor graph; at the same time, the prior information for sliding windows is set dynamically to maintain interframe constraints and ensure the accuracy of the state estimation after optimisation. First, the dynamic model of vehicle and the observation equation of VINS are introduced. Next, as a contrast, an Invariant Extended Kalman Filter (InEKF) is constructed. Then, the DSWFG algorithm is described in detail. Finally, based on the test data, the comparison experiments of Extended Kalman Filter (EKF), InEKF and DSWFG algorithms in different motion scenes are presented. The results show that the new method can achieve superior accuracy and stability in almost all motion scenes.

Signage design has been considered critically important for wayfinding, being a functional medium of delivering environmental information. Complex institutional environments have several factors affecting the wayfinding, including but not limited to the design of information signage and its visual preference. Visual preferences of information design in wayfinding signage vary, depending on the cultural and individual differences. This study explores the variance in design and visual preferences of wayfinding signage and its influencing elements. Responses through online questionnaire have been accumulated by the participants from Hong Kong and Pakistan based on their design and visual preference of campus wayfinding signage. Questions were asked related to the user preferences for signage colour if in line with the institutional visual identity, mono or multi-colour coding of information and its visual volume. In total, 170 university students and visitors participated in the exploratory study from the respective countries. The results demonstrated that participants of Hong Kong preferred inline colours of signage, along with mono or less colour coding and detailed information. While the other group preferred attractive colours with multi-colour coding and less detailed wayfinding information with pictograms. Individual differences concerning age, literacy level and gender were also computed, however trivial differences have been recorded. This study suggests the need for detailed cross-cultural investigation concerning elements of signage design and visual preference to identify the drivers for culturally consistent university signage.

This study aims to examine the predictors of professional commitment of the Chinese new generation, divided into post-80s and post-90s cohorts. A questionnaire survey was employed to collect data from Chinese seafaring officers of these cohorts. The results through hierarchical regression analysis present the two cohorts as having both similar and different predictors. The main difference is that company management and policies positively drive the post-80s cohort to work at sea but not the post-90s. The main similarity is that the work itself is the most important predictor for both cohorts. This study contributes to helping maritime companies to estimate the possibility of Chinese new generation officers quitting sea jobs and can be of value to both managers and authorities as they seek to comprehend the generational dynamic features to better cope with the problem of shortage of younger qualified officers.

Recently, the quality of Maritime Education and Training (MET) has drawn more attention from employers of the shipping industry, because incompetent officers have frequently contributed to ship accidents. The authors intend to explore answers to three questions: (1) Is the quality of Chinese MET satisfactory to the maritime stakeholders? (2) What are the major factors affecting the quality of cadet training? (3) Are there feasible solutions to improve the quality of MET? The authors take China, a major seafarers supplying country, as empirical evidence to disclose the causes of the problems. By an exploratory factor analysis technique, this paper presents the findings of semi-structured interviews and questionnaire surveys and identifies four principal factors affecting the quality of MET in China. Shortage of skillful instructors, lack of onboard training, over-reliance on theoretical teaching, and limited funding sources are prominent factors in this context. Practical solutions are proposed for the purpose of improving the overall competence of Chinese cadets expected to become the dynamic workforce for the global shipping industry.

The inertial navigation system/Doppler velocity logger (INS/DVL) plays an important role in ocean navigation. Any DVL malfunction poses serious risks to navigation. A precise detection system is required to detect the initial moments of DVL signal malfunctions; moreover, with loss of DVL, a fault-tolerant scheme (FTS) is necessary for DVL signal reconstruction. In this paper, an evolutionary knowledge-based method, namely improved evolutionary TS-fuzzy (I-eTS), is adopted to build an artificial intelligence (AI)-based pseudo DVL to deal with long-term outage of DVL. By employing Gaussian process regression (GPR) models for fault detection, a new FTS is constructed. To verify the effectiveness of the new fault detection and fault tolerance system, navigation data is gathered by a test setup and algorithms are performed in the laboratory. In the tests, it is demonstrated that the proposed FTS leads to rapid detection of both gradual and abrupt faults, which leads to less interaction between fault detection and FTS.

Array antenna beam forming has high potential to improve the performance of the global navigation satellite system (GNSS) in urban areas. However, the widespread application of array antennas for GNSS multipath mitigation is restricted by many factors, such as the complexity of the system, the computation load and conflicts between required performance, cost budget and limited room for the antenna placement. The scope of this work is triplicate. (1) The pre-correlation beam forming structure is first suggested for multipath mitigation to decrease the system complexity. (2) With the pre-correlation structure, the equivalence of adaptive beam forming to quiescent beam forming is revealed. Therefore, the computational load for beam forming is greatly decreased. (3) A theoretical model is established to link the benefits of beam forming with GNSS performance improvement in terms of pseudorange quality. The model can be used by industry to balance the aforementioned restrictions. Numerical results with different array settings are given, and a 2 × 2 rectangle array with $0.4\lambda $ element spacing is suggested as a cost-effective choice in GNSS positioning applications in urban canyon areas.

In view of many problems associated with the availability of global navigation satellite system (GNSS) signals in high-altitude space, this paper presents a comprehensive and systematic analysis. First, the coverage and strength characteristics of GNSS signals in high-altitude space (i.e., space above the GNSS constellation) are presented, and the visibility of GNSS signals is evaluated by combining these two factors. Second, the geometric configuration and geometric dilution of precision (GDOP) of visible GNSS satellites are analysed. Then, the Doppler shift range of the GNSS signals is deduced based on the dynamic performance of high-altitude spacecraft. Finally, taking GaoFen-4 (GF-4) as the application object, the availability of GNSS signals is simulated and evaluated. GNSS signals in high-altitude space are generally weak, and the visible GNSS satellites are concentrated in the high-elevation range. The combination of main and side lobe signals and compatibility of multiple constellations can increase the number of visible satellites, improve the geometry configuration, reduce GDOP, and thus improve the availability of GNSS signals. The results of this research can provide technical support for the design and development of GNSS receivers suitable for high-altitude space.

The strapdown inertial navigation system (SINS) with integrated Doppler velocity log (DVL) is widely utilised in underwater navigation. In the complex underwater environment, however, the DVL information may be corrupted, and as a result the accuracy of the Kalman filter in the SINS/DVL integrated system degrades. To solve this, an adaptive Kalman filter (AKF) with measurement noise estimator to provide noise statistical characteristics is generally applied. However, existing methods like moving windows (MW) and exponential weighted moving average (EWMA) cannot adapt to a dynamic environment, which results in unsatisfactory noise estimation performance. Moreover, the forgetting factor has to be determined empirically. Therefore, this paper proposes an improved EWMA (IEWMA) method with adaptive forgetting factor for measurement noise estimation. First, the model for a SINS/DVL integrated system is established, then the MW and EWMA based measurement noise estimators are illustrated. Subsequently, the proposed IEWMA method which is adaptive to the various environments without experience is introduced. Finally, simulation and vehicle tests are conducted to evaluate the effectiveness of the proposed method. Results show that the proposed method outperforms the MW and EWMA methods in terms of measurement noise estimation and navigation accuracy.

The positioning technique employing the ubiquitous signals of opportunity of non-cooperative satellites does not send special navigation signals, instead it passively receives satellite signals as noise, presenting advantages of concealment and difficulty for potential attackers. Thus, this study investigates the ranging principle and model using non-cooperative communication satellites and a time difference estimation algorithm. The technology of time difference measurement under non-cooperative observation mode was determined and simulated. A test platform for time difference measurement was built to receive the signal from an unknown geostationary Earth orbit communication satellite and verify the ranging feasibility and performance. The ranging accuracy was found to be smaller than 6 m, as demonstrated by experimental data, which shows the viability of the proposed positioning technique for ranging technology.