Search Results (11)

Container liner shipping companies operate within a complex environment where they must balance profitability and service reliability. Meanwhile, evolving regulatory policies, such as surcharges imposed on ships of a particular origin or type on specific trade lanes, introduce new operational challenges. This study addresses the heterogeneous ship routing and demand acceptance problem, aiming to maximize two conflicting objectives: weekly profit and total transport volume. We formulate the problem as a bi-objective mixed-integer programming model and prove that the ship chartering constraint matrix is totally unimodular, enabling the reformulation of the model into a partially relaxed MIP that preserves optimality while improving computational efficiency. We further analyze key mathematical properties showing that the Pareto frontier consists of a finite union of continuous, piecewise linear segments but is generally non-convex with discontinuities. A case study based on a realistic liner shipping network confirms the model’s effectiveness in capturing the trade-off between profit and transport volume. Sensitivity analyses show that increasing freight rates enables higher profits without large losses in volume. Notably, this paper provides a practical risk management framework for shipping companies to enhance their adaptability under shifting regulatory landscapes. Full article

Accidental ground surcharge loads can induce adverse effects such as segment cracking in underlying shield tunnel structures, with particularly pronounced impacts on pre-damaged tunnel segments. Cracks represent one of the most common initial damage forms in shield tunnel structures. To investigate through-crack failure mechanisms in shield tunnel segments with initial cracks under surcharge loading, this study conducted 1:8 scaled indoor model tests, considering factors including initial crack length, quantity, morphology, and surcharge position. Research findings demonstrate that increased initial crack length and quantity significantly reduce the critical load required for through-crack formation. Specifically, segments with 9 cm longitudinal initial cracks required 50.9% less load to develop through-cracks compared to intact segments. Similarly, segments containing two 9 cm circumferential initial cracks exhibited a 22.1% reduction in critical load relative to those with single circumferential cracks. Initial cracks in pre-damaged segments substantially influence the propagation path of new cracks during subsequent loading failures. The detrimental effects of staggered longitudinal-circumferential initial cracks exceed those of purely longitudinal cracks, which themselves pose greater risks than circumferential cracks alone. Bilateral surcharge loading significantly increases the critical load threshold for through-crack formation compared to unilateral loading. This highlights the severe structural risks associated with uneven load distribution. Full article

The sliding of roof snow may result in surcharges of snow load on lower roofs or the injury of pedestrians on the ground. It is therefore of great significance to study the mechanism of roof snow sliding, such that prevention or control measures can be developed to manage the risk. Considering four commonly used roofing materials, glass, steel, membrane, and concrete, two types of experiments were carried out in this study to possibly reveal the influence of roofing materials on the shear strength of the roof–snow interface: one is the critical angle tests where the angle at which the snow starts to slide off from the roof is tested, and the other is the shearing tests which aim to test the shear strength of the roof–snow interfaces at specific temperatures. The results showed that the critical angle for roof snow sliding, as well as the shear strength of the roof–snow interface for the four considered roofing materials, show a U-shape trend with the increase in surface roughness and that the shear strength of the roof–snow surface ranges from 0.15 kPa to 2 kPa for the cases considered, while the strength reaches its maximum at certain temperatures near −5 °C for a specific roofing material and snow thickness. These findings could be a useful reference for future experimental or simulation studies on roof snow sliding. Full article

The accelerated growth and interconnectedness of financial institutions and movement towards products and activities outside the regulatory purview have been met with huge concerns. South Africa is one of the emerging economies that this conundrum has beset. Any potential instability in the financial sector likely poses insurmountable consequences and unprecedented government intervention, especially given that the country currently has no deposit insurance scheme. Although it is easy to justify the channels through which banks contribute to destabilising financial markets, it remains a controversial issue for insurers and other non-banking institutions. This study aims to empirically quantify the contribution of banks and insurers to aggregate the systemic risk of their respective industries by employing the component expected shortfall (CES). The CES is a robust quantitative systemic risk measure that allows for a comprehensive assessment of systemic risk by considering the contributions of individual financial components. Our findings demonstrate that the rankings from the CES framework are closely aligned with the regulatory D-SIB surcharges of the banking entities included in the study. The close alignment of both approaches is primarily due to the consideration of the size of an institution, amongst other factors. Full article

Internal erosion refers to the seepage-induced fine particle migration phenomenon in soil. Deep alluviums in valleys usually contain cohesionless gap-graded sandy gravels with poor internal stability. The construction of embankment dams on such alluviums could pose a high risk of internal erosion. This study systematically investigated the internal erosion of cohesionless gap-graded sandy gravels with an emphasis on the effects of gradation characteristics and particle morphology. A series of large-scale internal erosion tests were conducted on gap-graded sandy gravels with different gap ratios, fines contents, and coarse particle morphologies under the surcharge pressure of 1 MPa. The internal erosion characteristics, including soil permeability, eroded soil mass, and soil deformation during the erosion process were comparatively analyzed in combination with a meso-mechanism interpretation. The results show that the increase of the gap ratio can reduce the internal stability of soil and promote the mechanical instability. Fines content affected the permeability and internal stability of soil by altering the filling state of inter-granular pores and the constraints on fine particles. Coarse particles with higher roundness, sphericity, and smoothness can facilitate the movement of fine particles and promote the mechanical instability of the soil matrix. Full article

Urban pluvial floods (UPFs) are a threat that is expected to increase with economic development, climate change, and the proliferation of urban cover worldwide. Methods to assess the spatiotemporal magnitude of UPFS and their impacts are needed to research and explore mitigation measures. This study presents a method for the assessment of UPFs and their impacts by combining a hydrodynamic sewer system model with a GIS-based overland diffusive flow algorithm. The algorithm is implemented in the software GIS-based Agent-based Modeling Architecture (GAMA) along with the depth-damage functions and land use data to estimate financial impacts. The result is a dynamic and interactive model that allows the user to monitor the events in real-time. Functionality is demonstrated in a case study in Dresden, Germany and with ten to 100-year design storms. The majority of flood extents and damages occur in the early stages of the event. Sewer surcharge emerges from few of the manholes, suggesting early action vitally reduces flood risks and interventions at a few hot spots, largely reducing impacts. Flood protection barriers were interactively implemented as a potential response measure in the hot spot areas reducing the damage by up to 90%. The user can compare different parameters in a visually compelling way that can lead to a better understanding of the system and more efficient knowledge transfer. Full article

The article is devoted to the method of determining the risk surcharge in rental rates for special technological equipment. The relevance and features of the task, as well as existing approaches to solve it in other subject areas, are described. The risk of landlords is highlighted as “the inability to fully ensure the receipt of a stable income recorded in the lease agreement”. The three most significant risk-forming factors are highlighted: the early return of equipment, the emergence of debt on payments from the tenant, and the breakdown of equipment due to the fault of the tenant. A fuzzy model for estimating the likelihood of the manifestation of risk-forming factors is proposed depending on the following challenges of the rental pillar: the size of the enterprise, financial stability, the age of the enterprise, the number of current trials, and the reputation of the enterprise. Describes: universal linguistics for input and output values characterizing risky components, logical output rules, and the assessment of the likelihood of risk in general. Based on the SciKit-Fuzzy library for the Python language, the model studies all available values of input variables, and tenants are presented separately on the boundary values of the enterprise parameters. A methodology for determining the rental rate, taking into account the risk surcharge, is proposed. Full article

Currently, adopted runoff analysis models focus on the characteristic factors of watersheds and neglect the analysis of the flow in conduits. Additionally, the usually employed XP-SWMM modeling package generally underestimates the flood area because it considers manholes as nodes and does not consider local head losses according to the shape and size of the nodes. Therefore, it is a necessity to consider the loss coefficient in surcharge manholes to improve inundation and runoff analysis methods. This study aims at improving the accuracy of discharge analysis before analyzing the storage and runoff reduction effects of storage facilities. Hydraulic experiments were conducted according to the changes in discharge and manhole shapes. We show that the flood area increases as the overflow discharge at manhole increases due to the application of the head loss coefficient. We demonstrate a concordance rate ≥95% between results and observed flood area when accurate input data (from the parameters of the target watershed) and the head loss coefficient (from hydraulic experiments) are applied. Therefore, we demonstrate that the result of our 2D inundation analysis, considering the head loss coefficient in surcharge manhole, can be used as basic data for accurately identifying urban flood risk areas. Full article

How to consider the a priori risks in experience-rating models has been questioned in the actuarial community for a long time. Classic past-claim-rating models, such as the Buhlmann–Straub credibility model, normalize the past experience of each insured before applying claim penalties. On the other hand, classic Bonus–Malus Scales (BMS) models generate the same surcharges and the same discounts for all insureds because the transition rules within the class system do not depend on the a priori risk. Despite the quality of prediction of the BMS models, this experience-rating model could appear unfair to many insureds and regulators because it does not recognize the initial risk of the insured. In this paper, we propose the creation of different BMSs for each type of insured using recursive partitioning methods. We apply this approach to real data for the farm insurance product of a major Canadian insurance company with widely varying sizes of insureds. Because the a priori risk can change over time, a study of the possible transitions between different BMS models is also performed. Full article

Urban flooding is a growing concern in Northern Europe. While all countries in this region invest substantial resources into urban flood risk management, all property owners have unequal opportunity to have their flood risk managed. This paper presents the notion of equity in the urban flood risk management, focusing on urban flood exposure and compensation after sewage surcharge on the 31 August 2014 cloudburst over Malmö in Sweden. All damage claims and the procedures assessing them were analysed based on the type of sewer system (combined or separated) that affected the properties. The results demonstrated considerable systemic inequity in both flood exposure and damage compensation. The owners of properties connected to combined systems were four times more likely to make a damage claim, while having their damage claims approved just over half as often, compared with owners of properties connected to separated sewage systems. Considering the multifaceted nature of both inequities and their possible resolution, current praxis is not sufficient for the management of future urban drainage systems; not only concerning changing climatic conditions but also concerning social conditions. Full article

The climate change factor (CCF) is a precautionary instrument for technical flood protection that was introduced in Southern Germany in the early 2000s. The CCF was designed as a surcharge value to be added to all new technical flood protection facilities, such as dams, protection walls, and retention areas. This paper deconstructs the conditions and processes that led to the creation of this new policy instrument. Following the instrument choice framework, the paper analyzes in a heuristic manner, the institutions, actors, discourses, and decision context that were part of this process from the early 1990s to 2004, when the instrument was introduced. In order to better understand the scope of this regional instrument, the paper also briefly depicts four non-representative cases of flood risk and protection management, where the instrument was either applied or avoided. The article closes with an assessment of the CCF, concluding that the innovativeness of this instrument faded once the overarching sectoral paradigm shifted from technical flood protection to more comprehensive flood risk management. Full article