Hasil untuk "Harbors and coast protective works. Coastal engineering. Lighthouses"

Yusif Owusu, Komlan Agbéko Kpogo-Nuwoklo, Anthony Twum et al.

Reanalysis wave datasets are essential for understanding wave conditions along the West African coast, a region with over 350 million people and diverse economic activities. This study evaluates the effectiveness of various datasets, including ERA5, WAVERYS, satellite (HY-2B/HY-2C), and buoy measurements, focusing on significant wave height (Hs). WAVERYS was found to better match in situ conditions compared to ERA5, making it the preferred dataset for climate estimation. This study found that wave heights (Hs) of WAVERYS in the region range from 0.5 m to 3.2 m, with waves primarily coming from the south and southwest, having periods between 3.8 s and 25 s. Swell, originating from the South Atlantic Ocean, dominates the wave climate, while local wind waves contribute only about 5% to the overall sea state energy. Seasonal analysis showed that the highest waves occur between June and September, coinciding with the South Atlantic winter and stronger winds. The validation performed in this study confirms that the WAVERYS reanalysis can reliably be used as a source of wave data in the Gulf of Guinea. This recommendation is based on its consistently better agreement with the available in situ observations and its improved representation of wave dynamics in the region. At locations where buoy measurements exist, in situ data should remain the primary reference for site-specific applications; however, such measurements are spatially sparse and temporally limited across West Africa. Consequently, WAVERYS provides a practical and robust alternative for regional-scale analyses, long-term assessments, and operational applications in areas lacking direct observations, making it particularly valuable for coastal risk assessment, engineering design, and marine operations in the region.

Fengling Yu, Junyang Ma, Zhaoquan Huang et al.

Deep insight into the spatialtemporal composition and distribution dynamics of suspended particulate organic carbon (POC) and sedimentary total organic carbon (TOC) within the mountainous river-estuary-bay continuum provides us with a unique perspective for examining the impact of estuarine flow on the material cycle within the river-estuary-bay systems. In this study, we conducted a comparative analysis of the river-estuary-bay continuum of two subtropical mountainous rivers, the Jiulong River (JLR) and the Zhangjiang River (ZJR), southern China. Seasonal samples of suspended particles and surface sediments were collected from the lower river reaches, estuaries, and bay areas. Both suspended and sedimentary samples were analyzed for organic content and their isotopic signatures (δ13C), and C/N ratios. The results reveal notable differences between the two systems. The JLR system exhibits stronger seasonal and spatial variations in POC sources compared to the ZJR system. In contrast, the estuary and bay of the ZJR system show more pronounced marine POC signals than those of the JLR system. In the sediments of the estuary and bay, soil organic matter and C3 plants contribute to over 60 % of the total organic matter in the JLR system, whereas in the ZJR system, marine organic matter and soil are the two most significant contributors. This study identifies that estuarine hydraulic conditions control the provenance, dynamics, and fate of particulate organic matter (POM). River discharge plays a pivotal role in regulating the dispersion of terrestrial organic matter in the estuary; Estuarine circulation and the position of the turbidity maximum zone govern the temporal and spatial distribution of sedimentary organic matter. Moreover, high soil contribution to the estuarine and bay sediment organic matter suggests strong soil erosion of adjacent land, likely attributed to human activities. Our findings highlight the high sensitivity of POC composition and dynamics in these mountainous river-estuary-bay systems to changes in river discharge, tidal current, and maybe wave conditions. The results of this study will deepen our understanding of the dynamics and fate of POM from different sources within the mountainous river-estuary-bay continuum and provide vital information for the effective management of these highly dynamic and sensitive ecosystems.

Oleksandr Kosenkov, Ehsan Zabardast, Jannik Fischbach et al.

Implementing privacy by design (PbD) according to the General Data Protection Regulation (GDPR) is met with a growing number of requirements engineering (RE) approaches. However, the question of which RE method for PbD fits best the goals of organisations remains a challenge. We report our endeavor to close this gap by synthesizing a goal-centric approach for PbD methods assessment. We used literature review, interviews, and validation with practitioners to achieve the goal of our study. As practitioners do not approach PbD systematically, we suggest that RE methods for PbD should be assessed against organisational goals, rather than process characteristics only. We hope that, when further developed, the goal-centric approach could support the development, selection, and tailoring of RE practices for PbD.

Tanja E. J. Vos, Tijs van der Storm, Alexander Serebrenik et al.

Software engineering is the invisible infrastructure of the digital age. Every breakthrough in artificial intelligence, quantum computing, photonics, and cybersecurity relies on advances in software engineering, yet the field is too often treated as a supportive digital component rather than as a strategic, enabling discipline. In policy frameworks, including major European programmes, software appears primarily as a building block within other technologies, while the scientific discipline of software engineering remains largely absent. This position paper argues that the long-term sustainability, dependability, and sovereignty of digital technologies depend on investment in software engineering research. It is a call to reclaim the identity of software engineering.

Sanaz Sediqi, Jueyi Sui, Guowei Li

Understanding the hydraulic resistance is vital for river engineering projects that include the installation of in-stream infrastructure, such as bridge abutments, which directly impact flow dynamics and sediment transport. In this study, based on laboratory experiments in a large-scale flume, the hydraulic resistance of flow has been investigated, considering the combined effects of submerged vegetation, ice cover, and bed sediment. The bed and ice cover shear stress, vegetative drag, and the composite Manning's roughness coefficient under various conditions have been calculated and discussed. An empirical model that indicates the relationship between the composite Manning's roughness coefficient of the channel and the roughness coefficients of the bed, ice cover, and vegetation has been developed. Results indicated that the presence of an ice cover leads to a noticeable increase in the channel bed shear stress, with a greater contribution of the shear stress in vegetated beds under ice-covered flow conditions, accounting for up to 60% of the total shear stress compared to that under open flow conditions with vegetated beds. Compared to the square arrangement of vegetation elements in the bed, the presence of vegetation arranged in a staggered pattern in the bed results in a decrease in the bed shear stress but an increase in the vegetation drag force. Findings emphasize the importance of vegetation density as the primary factor influencing the drag coefficient. Notably, the drag force exceeds the shear force in all experimental scenarios, accounting for 85% of the total resistance force. Furthermore, Manning's roughness coefficient for the vegetation patch exhibits higher values than that for the ice cover. A clear correlation exists between Manning's coefficients and the Froude number; the higher the flow Froude number, the less the Manning's roughness coefficient.

Binh Quang Nguyen, Sameh A. Kantoush, Ngoc Duong Vo et al.

Sediment estimation would help practice sustainable watershed management and efficient reservoir operation. Different methods exist to estimate reservoir sedimentation based on the differences in sediment yield flowing in and releasing from the reservoir and successive bathymetric field measurements. This paper investigates the variability in sediment yield from watersheds and sedimentation in the A Vuong reservoir in central Vietnam using the soil and water assessment tool (SWAT) compared with bathymetry mapping. Bathymetry data were collected in 2003, 2015, and 2021 and conducted in 2022. SWAT was calibrated from 1996 to 2008 and validated from 2009 to 2020 using monthly observations. SWAT performs well and can accurately simulate monthly streamflow and sediment yield. The goodness-of-fit analyses suggested that the area list representation of the watershed behavior and satisfactory Sutcliffe efficiency (NSE = 0.86) values for streamflow were obtained during the calibration and validation periods. For sediment simulation, the efficiency is lower than streamflow's, with NSE in the validation values of 0.61. The results showed that the sedimentation estimate from the SWAT model is smaller than that from bathymetry. A Vuong reservoir's annual storage capacity loss due to sedimentation accumulation from the SWAT model and bathymetry was 0.08% and 0.38%, respectively. Based on the bathymetry data, we estimated that the average rate of sedimentation deposition of A Vuong reservoir was 1.3 Mm3/y. The average calculated net deposition value was 4.3 m (0.3 m per year) within fourteen years of operation. The study outcomes demonstrated that the framework approach may transfer to an ungauged catchment and address the complex sedimentation problem in tropical regions.

Bhaswatee Baishya, Arup Kumar Sarma

The reduction in water retention capacity due to sedimentation in wetlands poses a serious threat to the ecology of this imperative freshwater resource. This also increases the risk of flooding in the river catchment areas that feed these wetlands. Sediments are mostly produced by unplanned development and hillcutting in upstream catchments. Henceforth, it is crucial to understand the trend in sediment deposition to determine management measures. However, measuring sediment deposition in wetlands is challenging. This study investigates a novel and cost-effective approach to discover trends in sediment deposition within wetlands via geospatial techniques and compares their water extents in the Deepor Beel Wetland, a Ramsar site in Assam, India. The water spread areas were assessed via supervised classified Landsat images and the band rationing technique, i.e., the normalized difference pond index (NDPI). This study establishes that sedimentation causes the water level in wetlands to rise, resulting in an increase in the area of water spread. This often suggests that the lean period water volume is increasing, indicating better health of the stream-wetland ecosystem. However, this apparent increase in water volume is actually due to the displacement of water by the sediment that has been deposited on the bed over time. This approach has identified a reduction in the water holding capacity of the wetland to 9.19 million m3 in 18 years by utilizing geospatially derived water spread and elevation data from two years (2003 and 2021) with comparable rainfall. In the absence of recent and past years with comparable precipitation, the proposed method can still be applied by adjusting the apparent increase in volume by considering the difference in the net inflow volume between the two years of interest. The results of sediment transport toward the wetland, as computed by the Soil and Water Assessment Tool (SWAT) model while accounting for the sediment retention rate of the wetland, strongly agree with the proposed approach. The present approach can be extended to similar stream-wetland ecosystems to examine sediment dynamics and help create better management strategies for wetlands and associated catchment conservation and restoration.

William A. Gough

A new marine climate metric, marine season, is introduced for Foxe Basin, Nunavut, Canada capturing the time of the year that the Basin is influenced by open water. The metric is developed with a day-to-day temperature variability framework using the Hall Beach (Sanirajak) climate record (1957–2023). Day-to-day minimum temperature variability provides a clear signal of the marine season. The new metric is compared to the more traditional breakup and freeze-up dates of sea ice that uses a 5/10th sea-ice spatial coverage threshold. While the two metrics are in general agreement, some important differences occur related to the time required for the breakup (full ice coverage to 5/10th sea-ice coverage). The timing from onset of the marine season to 5/10th ice coverage has shortened in time in a statistically significant fashion, indicating a more rapid breakup in recent years. In contrast, the freeze-up period, 5/10th to full sea-ice coverage has increased. The longer ice-free season, as determined by sea-ice data, arises primarily from open water changes in the breakup (shorter) and freeze-up (longer) period timing. These are novel insights that suggest that the basic sea-ice regime, oscillating from a full sea-ice platform and ice-free conditions has not changed, but rather the observed changes are in the nature of the transitions between these two states, breakup and freeze-up.

Cristiane Bahi dos Santos, Iran Stallivière Corrêa, Jair Weschenfelder et al.

Connections between changes in sediment distribution and diatom species are sensitive to environment-related deposition patterns of fine-grained sediment. A large lagoon in the southernmost Brazilian coastal plain was selected to test the sensitivity of diatoms to sediment changes and their ability to classify depositional environments. Selected grain-size parameters, including mean grain size, skewness, kurtosis, standard deviation, and sand-silt-clay ratios, were evaluated for interpretation. The trigonal diagram shows that most of the lagoon sub-bottom deposits lie in the fine-grained tail. Silt is dominant within the Holocene fluvial-estuarine, estuarine-transitional, and shallow marine deposits. Sand fractions (> 76%) are distributed in the coastal barrier and in a few fluvial-estuarine intervals. Most deposits are polymodal, lying between poorly sorted sediment, indicating a low-energy depositional environment. The results were interpreted as indicated by the Principal Component Analysis (PCA), which revealed resulting shifts in sediment and diatom composition connected to five sedimentary facies controlled by sea-level oscillations. Diatom species recovered from sediment cores have distinctive capacities for living under high marine, freshwater, and terrestrial conditions. Each quadrant of the PCA reflects the adaptation of species to particular depositional conditions during the Late Pleistocene and Holocene. Allochthonous taxa provide valuable ecological information about adjacent environments in the coastal area, offering insight into the paleogeography of the study area. The major advantage of the analytical methods is their applicability in distinguishing different environments involving mixed deposition and transport mechanisms. The sediment deposited on the bottom of a large lagoon provide significant implications not only for sedimentological analysis by improving understanding of high deposition of mud and fine-grained sands but also for predictions of the source-to-sink routes.

Carolyn Seaman, Rashina Hoda, Robert Feldt

The paper entitled "Qualitative Methods in Empirical Studies of Software Engineering" by Carolyn Seaman was published in TSE in 1999. It has been chosen as one of the most influential papers from the third decade of TSE's 50 years history. In this retrospective, the authors discuss the evolution of the use of qualitative methods in software engineering research, the impact it's had on research and practice, and reflections on what is coming and deserves attention.

Zhimin Zhao

Foundation models (FMs), particularly large language models (LLMs), have shown significant promise in various software engineering (SE) tasks, including code generation, debugging, and requirement refinement. Despite these advances, existing evaluation frameworks are insufficient for assessing model performance in iterative, context-rich workflows characteristic of SE activities. To address this limitation, we introduce \emph{SWE-Arena}, an interactive platform designed to evaluate FMs in SE tasks. SWE-Arena provides a transparent, open-source leaderboard, supports multi-round conversational workflows, and enables end-to-end model comparisons. The platform introduces novel metrics, including \emph{model consistency score} that measures the consistency of model outputs through self-play matches, and \emph{conversation efficiency index} that evaluates model performance while accounting for the number of interaction rounds required to reach conclusions. Moreover, SWE-Arena incorporates a new feature called \emph{RepoChat}, which automatically injects repository-related context (e.g., issues, commits, pull requests) into the conversation, further aligning evaluations with real-world development processes. This paper outlines the design and capabilities of SWE-Arena, emphasizing its potential to advance the evaluation and practical application of FMs in software engineering.

S Coombes

Simple spiking neural network models, such as those built from interacting integrate-and-fire (IF) units, exhibit rich emergent behaviours but remain notoriously difficult to analyse, particularly in terms of their pattern-forming properties. In contrast, rate-based models and coupled phase oscillators offer greater mathematical tractability but fail to capture the full dynamical complexity of spiking networks. To bridge these modelling paradigms, Hermann Haken -- the pioneer of Synergetics -- introduced the Lighthouse model, a framework that provides insights into synchronisation, travelling waves, and pattern formation in neural systems. In this work, we revisit the Lighthouse model and develop new mathematical results that deepen our understanding of self-organisation in spiking neural networks. Specifically, we derive the linear stability conditions for phase-locked spiking states in Lighthouse networks structured on graphs with realistic synaptic interactions ($α$-function synapses) and axonal conduction delays. Extending the analysis on graphs to a spatially continuous (non-local) setting, we develop a variant of Turing instability analysis to explore emergent spiking patterns. Finally, we show how localised spiking bump solutions -- which are difficult to mathematically analyse in IF networks -- are far more tractable in the Lighthouse model and analyse their linear stability to wandering states. These results reaffirm the Lighthouse model as a valuable tool for studying structured neural interactions and self-organisation, further advancing the synergetic perspective on spiking neural dynamics.

Thomas S. N. Oliver, Michael A. Kinsela, Thomas B. Doyle et al.

The beach–foredune system at Bengello Beach has been monitored monthly to bimonthly at four profiles (P1–P4) since 1972 and documented the building of a foredune. This paper addresses the remarkable changes which occurred in 2022 as storm waves overtopped and trimmed this foredune at all profiles, then later removed this entire feature at two of the profiles (P3, P4) but not the others (P1, P2). Wave parameters for these storm events, measured by deepwater and nearshore wave buoys, enable a comparison of storm characteristics and resulting beach–foredune impact. During the storm event which destroyed the foredune, nearshore wave height exceeded deepwater wave height, in contrast with other storms that year. The beach–foredune lost 78 m3/m in 2022 and the notable 1974 storms that impacted this coastline resulted in 95 m3/m volume loss. During 2023, beach recovery has occurred, but not rebuilt the foredune. It had persisted for ~40 years enduring many other severe storm events, and the coastal protection afforded by the dune system has been compromised. This highlights the need to consider dune morphology in assessments of erosion hazard and inundation risk along similar coastlines.

Renato Castiglia Feitosa, Paulo Cesar Colonna Rosman

The ocean disposal of wastewater is an efficient alternative in the sewage system of coastal areas since the urban density of such regions is a barrier to the settlement of conventional sewage treatment plants. In addition, the associated costs of this alternative are significantly lower than the convention in the long term. The degradation of microbiological contaminants strongly depends on solar radiation and the factors that regulate its intensity, such as the depth of the effluent plume, seasons, and cloud cover. The submarine disposal of domestic sewage constitutes a low-sanitation-risk alternative regarding the contamination of bathing areas. The results based on computational modeling corroborate this alternative, showing that the coastal zone is not affected by marine sewage discharges.

M. Luisa Martínez, Rodolfo Silva, Octavio Pérez-Maqueo et al.

The real estate business on sandy coasts and coastal dunes has increased dramatically over the last decades because of the growing demands for leisure activities which, consequently, have yielded important economic gains. Such ravaging exploitation results in the replacement of sandy ecosystems with tourism-oriented settlements, infrastructure, and facilities. As the sandy beaches and coastal dunes become deteriorated or eliminated, their protective role is lost, and the hydrometeorological risks to which the increasing human coastal populations are exposed grow, especially in a climate change scenario with increasing storminess. Furthermore, when possible, the expansion of the tourism industry continues searching for new, unspoiled locations, and the cycle begins again. This situation leads to the dilemma of coastal management: should we continue with the over-exploitation of sandy coasts for growing economic benefits? Or should we preserve the coasts for protection against the impact of increasing storms and sea level rise and to benefit biodiversity? Although scientific evidence demonstrates the relevance of protecting the coasts, coastal development plans continue to ignore these findings. What are the key drivers for these trends? We first looked for scientific evidence of the appraisal of the esthetic beauty of the beach and coastal dunes, as highly important drivers of urbanization and coastal environmental change. We then looked for evidence that demonstrated how coastal dunes offer storm protection Finally, we examined if the conservation of beaches and coastal dunes can be compatible with non-intrusive tourism. In summary, through the literature review and our own data, we show how different alternatives may help achieve a more sustainable coastal tourism by combining economic necessities with environmental concerns.

Eduard C. Groen, Kazi Rezoanur Rahman, Nikita Narsinghani et al.

The farming domain has seen a tremendous shift towards digital solutions. However, capturing farmers' requirements regarding Digital Farming (DF) technology remains a difficult task due to domain-specific challenges. Farmers form a diverse and international crowd of practitioners who use a common pool of agricultural products and services, which means we can consider the possibility of applying Crowd-based Requirements Engineering (CrowdRE) for DF: CrowdRE4DF. We found that online user feedback in this domain is limited, necessitating a way of capturing user feedback from farmers in situ. Our solution, the Farmers' Voice application, uses speech-to-text, Machine Learning (ML), and Web 2.0 technology. A preliminary evaluation with five farmers showed good technology acceptance, and accurate transcription and ML analysis even in noisy farm settings. Our findings help to drive the development of DF technology through in-situ requirements elicitation.

AHM Mainul Islam, Timothy J. Assal

Cyclones are a key disturbance in mangrove ecosystems, but it is challenging to assess post-storm impacts over large areas, along with the recovery of these systems at broad temporal scales. Given the high frequency of these events in the Sundarbans region, prompt and consistent assessment of vegetation conditions is an important research need. Several studies have assessed the impact of an extreme cyclone event in 2007 (Sidr); however, there is little agreement between the extent and severity of the disturbance footprint of the cyclone, and very few studies attempted to assess vegetation recovery. We used a MODIS (Moderate Resolution Imaging Spectroradiometer) time series (2001–2010) to calculate monthly plant productivity anomalies in Google Earth Engine. We summarized dry season anomalies to assess post-storm vegetation change and evaluate the recovery time. Approximately 2100 km², primarily on the east side, were impacted by Sidr. The number of damaged pixels was reduced by 55% the following dry season (2008) and 93% in the dry season of 2009, indicating a near-full recovery 26 months after the event. Our results provide an additional line of evidence to provide a rapid assessment of the post-storm vegetation damage. The simple framework used can provide a comprehensive view of the extent of the damage, including lag effects on vegetation, in just a matter of months after the event.

Chris T. Perry, Ines D. Lange, Marleen Stuhr

Standardised methodologies for assessing reef-derived sediment generation rates do not presently exist. This represents a major knowledge gap relevant to better predicting reef-derived shoreline sediment supply. The census-based SedBudget method introduced here generates estimates of sediment composition and grain-size production as a function of the abundance and productivity of the major sediment-generating taxa at a reef site. Initial application of the method to several reefs in the northern Chagos Archipelago, Indian Ocean, generated total sediment generation estimates ranging from (mean ± SE) 0.7 ± 0.1 to 4.3 ± 1.3 kg CaCO3 m−2 yr−1. Sediment production was dominated by parrotfishes (>90% at most sites), with site-variable secondary contributions from sea urchins (up to 20%), endolithic sponges (~1–7%) and benthic foraminifera (~0.5–3.5%). These taxa-level contributions are predicted to generate sediments that at all sites are coral- (83–94%) and crustose coralline algae-dominated (range ~ 5–12%). Comparisons between these estimates and sedimentary data from proximal reef and island beach samples generally show a high degree of consistency, suggesting promise in the SedBudget approach. We conclude by outlining areas where additional datasets and revised methodologies are most needed to improve rate estimates and hope that the methodology will stimulate research on questions around sediment production, transport and shoreline maintenance.

Svenja Karstens, Jenny Friedrich, Jana K. Geuer et al.

Shallow, semi-enclosed coastal systems are particularly prone to eutrophication. Depending on local site conditions and historical nutrient legacies, sea-based measures might be necessary in addition to land-based nutrient removal. In this study, C:N:P ratios were combined with open-source bathymetric information and linked with the prevailing geomorphological and sedimentological regimes to gain insights into nutrient hotspots and understand their sources and fate in coastal waters. Land-based sediment samples were taken behind outlets at three sites in Eckernförde Bay (Baltic Sea), and complemented with ship-based sampling at locations approximately 8 m and 12 m water depth. The total carbon, nitrogen and phosphorus concentrations in surface sediments increased at deeper sites. This suggests that an increased downslope particle transport and deposition regime, based on local geomorphology, might influence nutrient hotspots to a larger extent than proximity to sources (e.g., outlets). Overall, the recorded C:N ratios (mean = 28.12) were closer to the ratio of terrestrial plants than those of marine phytoplankton, indicating allochthonous sources of organic matter.

Natasha Fox, Jenna H. Tilt, Peter Ruggiero et al.

To meet the challenges of hazards impacting coastal communities, demand is growing for more equitable coastal natural hazard adaptation and disaster mitigation approaches, supported by co-productive research partnerships. This review paper outlines contemporary advances in hazard adaptation and disaster mitigation with attention to how an equity and justice framework can address the uneven impacts of hazards on marginalized and underserved communities. Drawing upon the allied concepts of distributive, procedural, systemic, and recognitional equity and justice, we illustrate how these concepts form the basis for equitable coastal resilience. To demonstrate how equitable resilience can effectively advance contemporary adaptation and mitigation strategies, we present two vignettes where collaborative partnerships underscore how equitable coastal hazard planning and response practices complement these processes in coastal zones subject to large earthquakes and tsunamis. The first vignette focuses on disaster response and takes place in the Tohoku region of Japan, with diverse gender and sexual minority community members’ experiences of, and responses to, the 2011 Tohoku disasters. The second vignette centers on hazard planning and takes place on the U.S. Pacific Northwest coast along the Cascadia Subduction Zone to demonstrate how principles of distributive, procedural, systemic, and recognitional equity can inform the co-production of alternative coastal futures that prioritize equitable resilience. From this discussion, we suggest applying an equity lens to research processes, including alternative futures modeling frameworks, to ensure that the benefits of hazard adaptation and disaster mitigation strategies are equitably applied and shared.