The International Regulations for Preventing Collisions at Sea (COLREGs) rely on vague terms, which challenges both human navigators and autonomous systems requiring computable representations. This study quantifies what experienced navigators consider a safe distance under the COLREGs, using fuzzy representations derived from expert judgement. In a structured international survey of experienced navigators, 194 of the 235 respondents supplied useable data on Closest Point of Approach (CPA) and Bow Crossing Range (BCR) in open sea conditions. These data were used to derive fuzzy membership functions. Results reveal that navigators require a larger margin ahead of the bow than at the closest point of approach, with a mean Medium BCR of 1.86 NM against a mean Medium CPA of 1.42 NM. The influence of rank, experience, ship type and ship length on the elicited values was tested; only experience produced significant differences, and the model output proved insensitive to them. A weighted fuzzy rule base was built from a separate panel of ten experts, who assessed navigational scenarios on a full mission simulator, and used to construct a fuzzy inference model of safe distance for encounters in which the target crosses ahead of own ship. The model was validated by leave-one-out cross-validation and against data from seven collisions and three close-quarters situations. The novelty lies in deriving the membership functions from a large expert panel rather than assuming them, in building the rule base from assessments of navigational scenarios rather than stated rules, and in validating the model against real collision data. This provides a quantified, human-centred contribution for decision-support systems.
This study develops a novel framework for carrying capacity assessment based on the historic centre of Dubrovnik, a UNESCO World Heritage Site. By involving residents, local staff, spillover dynamics and sentiment analysis, it advances traditional methodologies and offers a holistic approach to sustainable tourism management. The model strikes a balance between the development of tourism and the preservation of cultural heritage by taking into account overcrowding, infrastructure congestion and stakeholder tolerance. The scenario analysis provides actionable strategies to reduce congestion and increase resilience. In line with the UNESCO Sustainable Tourism Toolkit, this approach provides a replicable model for balancing tourism development with heritage conservation and provides practical lessons for other living heritage cities facing similar pressures.
This paper explores how ownership structure shapes corporate entrepreneurship, paying particular attention to the mediating role of the entrepreneurial climate. While entrepreneurship is often associated with privately-owned enterprises (POEs), state-owned enterprises (SOEs) face distinctive institutional and organisational challenges that can hinder their ability to foster innovation and risk-taking. This paper examines how state ownership affects entrepreneurial intensity through its impact on the internal climate for entrepreneurship, using multiple theory approach. Starting from the agency theory, we develop a theoretical framework by introducing a resource-based view and institutional theory. Using data from 139 Croatian firms with varying ownership structures, the study shows that the negative association between state ownership and entrepreneurial outcomes is not direct but is fully mediated by the entrepreneurial climate. These findings highlight the importance of internal organisational conditions in shaping entrepreneurial behaviour under state capitalism. The paper contributes to ongoing debates by integrating a multi-theoretical perspective and offering both theoretical and managerial insights into how ownership structures influence innovation and corporate entrepreneurship.
The study aimed to verify the possible use of DFT calculation in the prediction of the orientation in electrophilic aromatic substitution. An activated ortho/para orienting substrate, and a deactivated meta orienting substrate, were used in DFT calculations using B3LYP, B3PW91, BPV86, CAM-B3LP, HCTH, HSEH1PBE, LSDA, MPW1PW91, PBEPBE, TPSSTPSS, and WB97XD functionals. The results showed that the reactivity of anisole can be adequately described considering charge control in reaction performed in hard conditions (nitration), while frontier orbital control can play a role in reactions performed in softer conditions (chlorination). Nitration of benzaldehyde can be rationalized through Hirshfeld charges analysis. Neither the frontier orbital nor Mulliken charges approach adequately account for behavior observed in chlorination of benzaldehyde. The effect of different basis sets was tested performing calculations with B3LYP functional and aug-cc-pVDZ, 6-311G+(d,p), aug-cc-pVQZ, DGTZVP, and LanL2DZ basis sets. For anisole, all basis sets provided a HOMO electron density distribution consistent with experimental reactivity; Hirshfeld charges analysis consistently reproduced the observed reactivity of anisole across all tested basis sets. All the basis sets were able to explain the observed reactivity of benzaldehyde in hard experimental condition, while they failed to give a correct description when a softer reagent was used.
The Eastern Adriatic Sea is biogeographically complex, yet knowledge of its hydromedusae is fragmented across two centuries of uneven sampling and shifting taxonomy. This review integrates historical faunistic records (pre-1950), mid-century programmes (1950–2000), modern quantitative time series (post-2000), and citizen science observations to compile an updated checklist of 98 non-siphonophoran hydrozoan taxa. Records are synthesised across eight sub-regions, although the most continuous research has focused on the Northern Adriatic and the open South Adriatic. The clearest long-term signal is in the Northern Adriatic, where diversity collapsed by >60% from the 1960s to the 1980s, largely through the loss of meroplanktonic taxa with benthic polyp stages under eutrophication-driven hypoxia. Since 2000, oligotrophication coincides with a partial recovery, marked by the re-emergence of meroplankton and episodic intrusions of oceanic holoplankton (including Trachymedusae) linked to circulation regimes (BiOS). For the open South Adriatic, bathymetric distributions and diel vertical migration patterns are synthesised to characterise a persistent offshore core. Taxonomic updates and information on non-indigenous and bloom-forming taxa are provided. Methodological biases and gaps, especially polyp-stage ecology and spatial sampling voids, are highlighted, and routine DNA barcoding is recommended. The checklist provides a baseline for tracking change in a shifting ecosystem.
