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

Román Manuel Vásquez-Elizondo, Adrian Fagundo-Mollineda, Shrinivas Nandi et al.

This review synthesizes the literature on the degradation and decomposition of holopelagic <i>Sargassum</i>, with a focus on process dynamics, including microbial contribution, process descriptions, and ecological impacts. Our objective is to consolidate a robust knowledge framework to inform and optimize management strategies in affected areas. Overall, we observed that the current literature relies primarily on isolated field ecological descriptions rather than a coherent, unified research line; mechanistic studies, including bacterial pathways and factors controlling degradation, remain scarce. At the fine scale, microbial community shifts during decomposition are strongly linked to the sequential utilization of distinct organic substrates, thereby favoring the proliferation of microorganisms capable of degrading complex organic molecules and of bacterial groups involved in sulfur respiration, methanogenesis, and nutrient recycling. In the case of sulfur respiration, groups such as Desulfobacterales and Desulfovibrionales may be responsible for the reported H₂S emissions, which pose significant public health concerns. At a broad scale, degradation occurs both on beaches during emersion and in the water column during immersion, particularly during massive accumulations. The initial stages are characterized by the release of organic exudates and leachates. Experimental and observational studies confirm a strong early-stage release of H₂S until the substrate is largely depleted. Depending on environmental conditions, a significant amount of biomass can be lost; however, this loss is highly variable, with notable consequences for contamination studies. Leachates may also contain low but ecologically significant amounts of arsenic, posing a potential contamination risk. Decomposition contributes to water-quality deterioration and oxygen depletion, with impacts at the individual, population, and ecosystem levels, yet many remain imprecisely attributed. Although evidence of nutrient enrichment in the water column is limited, studies indicate biological nutrient uptake. Achieving a comprehensive understanding of degradation and decomposition, including temporal and spatial dynamics, microbiome interactions, by means of directed research, is critical for effective coastal management, improved mitigation strategies, industrial valorization, and accurate modeling of biogeochemical cycles.

Tab, Zhang, Bjorn De Sutter et al.

Empirical research in reverse engineering and software protection is crucial for evaluating the efficacy of methods designed to protect software against unauthorized access and tampering. However, conducting such studies with professional reverse engineers presents significant challenges, including access to professionals and affordability. This paper explores the use of students as participants in empirical reverse engineering experiments, examining their suitability and the necessary training; the design of appropriate challenges; strategies for ensuring the rigor and validity of the research and its results; ways to maintain students' privacy, motivation, and voluntary participation; and data collection methods. We present a systematic literature review of existing reverse engineering experiments and user studies, a discussion of related work from the broader domain of software engineering that applies to reverse engineering experiments, an extensive discussion of our own experience running experiments ourselves in the context of a master-level software hacking and protection course, and recommendations based on this experience. Our findings aim to guide future empirical studies in RE, balancing practical constraints with the need for meaningful, reproducible results.

Patricia G. F. Matsubara, Tayana Conte

Over twenty years ago, the Software Engineering (SE) research community have been involved with Evidence-Based Software Engineering (EBSE). EBSE aims to inform industrial practice with the best evidence from rigorous research, preferably from systematic literature reviews (SLRs). Since then, SE researchers have conducted many SLRs, perfected their SLR procedures, proposed alternative ways of presenting their results (such as Evidence Briefings), and profusely discussed how to conduct research that impacts practice. Nevertheless, there is still a feeling that SLRs' results are not reaching practitioners. Something is missing. In this vision paper, we introduce Evidence to Decision (EtD) frameworks from the health sciences, which propose gathering experts in panels to assess the existing best evidence about the impact of an intervention in all relevant outcomes and make structured recommendations based on them. The insight we can leverage from EtD frameworks is not their structure per se but all the relevant criteria for making recommendations to practitioners from SLRs. Furthermore, we provide a worked example based on an SE SLR. We also discuss the challenges the SE research and practice community may face when adopting EtD frameworks, highlighting the need for more comprehensive criteria in our recommendations to industry practitioners.

Jorge Melegati

The adoption of Generative AI (GenAI) suggests major changes for software engineering, including technical aspects but also human aspects of the professionals involved. One of these aspects is how individuals perceive themselves regarding their work, i.e., their work identity, and the processes they perform to form, adapt and reject these identities, i.e., identity work. Existent studies provide evidence of such identity work of software professionals triggered by the adoption of GenAI, however they do not consider differences among diverse roles, such as developers and testers. In this paper, we argue the need for considering the role as a factor defining the identity work of software professionals. To support our claim, we review some studies regarding different roles and also recent studies on how to adopt GenAI in software engineering. Then, we propose a research agenda to better understand how the role influences identity work of software professionals triggered by the adoption of GenAI, and, based on that, to propose new artifacts to support this adoption. We also discuss the potential implications for practice of the results to be obtained.

Fabiola Ivette Juárez-Chávez, Thelma Michelle Ruiz-Ruiz, Elia Inés Polanco-Mizquez et al.

When designing spatial planning programs for processes in coastal zones, it is essential to consider the connections between marine and terrestrial environments and to coordinate institutional work in their implementation. This study examines the environmental policies of two planning processes in the coastal zone, one terrestrial and one marine, which were formally developed and adopted through decrees in the State of Sonora (NW Mexico). The Gulf of California Marine Spatial Planning (MSP-GC) was decreed in 2006, and the Sonora Coast Land Spatial Planning (LSP-SC) was decreed in 2009 and updated in 2015. This study reviewed, compared, and spatially analyzed the environmental policies established by both planning processes. The results show that both planning processes contain environmental policies with limited links between the marine and terrestrial environments in practice. Both planning processes were enacted with effort, resources, and stakeholder participation, but have not been implemented effectively. It is essential to review the mandates of the decrees, conduct an integrated assessment of environmental policies, and seek ways for federal and State institutional structures to drive the implementation of these planning processes. Considering the dates of the MSP (2006) and LSP-SC (2015) decrees, now it is the right time to evaluate them.

Mohammadreza Maddahi, Robert Michael Boes, Ismail Albayrak

Sediment bypass tunnels (SBTs) divert sediment-laden flows from river systems around reservoirs to the tailwater reach and thus help prevent reservoir sedimentation. However, their bypassing efficiency largely depends on reservoir operation, particularly for type-B SBTs with an intake located within the reservoir. The present study aims to investigate the effect of reservoir operation conditions on the bypass efficiency of a type-B SBT at the case study Solis Reservoir in Switzerland. Four annual measurement campaigns were conducted in the reservoir between 2018 and 2021. Flow velocities were measured, and bathymetry was mapped using an acoustic Doppler current profiler at high spatial resolution along the elongated and narrow reservoir. In- and outflow sediment volumes were measured using turbidimeters and Swiss plate geophone systems and estimated by using state-of-the-art sediment transport equations, respectively. Two floods with one-year and five-year return periods, respectively, in 2019 and a one-year return period flood in 2020 were captured. The results show that the average sediment bypass efficiency, i.e. the ratio of outflowing to inflowing sediment volumes, increased from 17% to 88% by operating SBT. The results highlight that the SBT bypass efficiency is highly dependent on the reservoir water level. For high efficiencies above 170%, an optimal value of the reservoir drawdown level is around 813 m asl. Bypass efficiencies up to 250% indicate that the type-B SBT does not only stop sedimentation but can also help regain active storage volume of the reservoir if operated under optimal conditions in terms of reservoir water level. Without SBT operation, ca. 205,000 m3 of net sediment deposition volume would have resulted in an aggradation of 1 m on average from 2018 to 2021. The findings of this study contribute to improved SBT and reservoir operation regimes in terms of reducing the sedimentation rates and prolonging the reservoir lifetimes.

N. Al-Kharousi, A.R. Kacimov, A. Al-Maktoumi et al.

Sidr (Christ-thorn) phreatopytic-xerophitic wild trees growing in the reservoir area of the Al-Khoud groundwater recharge/flood protection dam in Muscat (Oman) were surveyed. Trees’ loci, heights and stem diameters were measured. Soil profiles were described in two pedons (trenches) excavated near two pilot trees. A remarkable increase in infiltration rate was observed when double-ring infiltrometers were placed near the tree stems and at the bottom of the trenches. Sap flow metering conducted on one tree over a period of 9 months resulted an average rate of 12.5 L/d. This value was used to evaluate the reservoir water balance, considering it as the difference between infiltration of ponded post-flash-flood water and transpiration. Sidr trees are recommended as excellent eco-engineers, that can alleviate the negative impact of reservoir bed siltation by enhancing the infiltration-recharge of the underlying aquifer.

Pritam Kumar, Anurag Sharma

The study aimed to explore three-dimensional turbulent flow properties and bed morphology in a partially vegetated channel with sand bed conditions. Presence of flexible vegetation in the river and its interaction with the flow are of great significance in understanding the momentum and mass transport in the flow. Experiments were conducted in a straight, tilting rectangular flume with staggered emergent vegetation covering half of the channel width. The results show that the presence of vegetation diverts streamwise velocity from the vegetated side to the non-vegetated side. The study reveals that the presence of vegetation leads to an increase in turbulent intensity, turbulent kinetic energy, and Reynolds shear stress at the transition area between the vegetated and non-vegetated sides of the channel. This increase is attributed to higher transverse flow and momentum exchange in the transition area between the vegetated and non-vegetated sides. In the vegetated side, the vegetation serves as an obstruction, reducing turbulent intensity, turbulent kinetic energy, and Reynolds shear stress compared to the transition area between the vegetated and non-vegetated sides. This reduction in turbulence supports the stability of bed materials and promotes sediment deposition. The presence of vegetation significantly alters the secondary current in the channel. Scour depth along the non-vegetated side was higher than the vegetated side, mainly because the flow concentrated in the centre and non-vegetated side of the channel. The investigation determines that the existence of vegetation on the vegetated side effectively protects against bed erosion and sediment transport. Understanding the impact of emergent flexible vegetation on flow properties and sediment transport can inform decisions about vegetation layouts in river ecosystems.

Alexander F. Nielsen, Angus D. Gordon

This article presents a rock armour stability formula for coastal revetments under depth-limited breaking waves that defines requisite armour mass as a function of incident wave energy. Parameters include wave height, wave period, toe depth, revetment slope, specific gravity of armour and water, percentage damage and the number of waves. The formula has been calibrated empirically based on university research flume test data. It departs from existing approaches by using wave energy in lieu of wave height as the disturbing parameter, but adopts other parameters developed by previous researchers. Results are compared with established formulae and display better coherence with the flume data. Testing constraints including possible scale effects are highlighted. Recommendations are made for further testing including the effects of seabed slope.

Hui Liang, Ruijing Jiang, Ronghua Liu et al.

Rainfall-induced flash floods often trigger active sediment transport and substantial morphological changes, which in turn affect flood dynamics. Previous numerical studies have mostly overlooked the strong interactions between flow, sediment transport, and morphological evolution, and inevitably their impacts on flash flooding have remained poorly understood. Here a two-dimensional (2D) coupled shallow water hydro-sediment-morphodynamic (SHSM) model is applied to reconstruct an extreme flash flood in the Jiuyuan Gully catchment, Beijing, China, in July 2023. The impacts of sediment transport and morphological change on the flash flood are evaluated by comparing the results of a shallow water hydrodynamic (HD) model and the SHSM model. The SHSM model is shown to outperform the HD model in reproducing the observed maximum water levels, as sediment transport and morphological changes are explicitly taken into account. Bed load sediment prevails, while its transport rate may amount up to 30 kg/(m·s) in the flood conveyance channel and deviate from the transport capacity determined in line with local flows, as sediment entrainment is hindered by the concrete-lined bed. Aggradation in the flood conveyance channel is significant, reaching 3.0 m locally. Accordingly, the water level increases, leading to overbank flooding and extended inundation over the floodplains and adjacent areas. Consequently, flash flooding is exacerbated. The current findings highlight the critical role of morphological change induced by active sediment transport in modifying flash flooding, underscoring the significance of morphological change for practical flood warning and development of effective risk management strategies.

Thaynara Raelly da Costa Silva, André Magalhães, Adria Davis Procópio et al.

Given the high sensitivity of small estuaries to environmental changes, the present study aimed to investigate how climate-induced stressors—particularly rainfall and salinity—affect zooplankton community structure in the Amazonian Taperaçu estuary (northern Brazil), where limited spatial scale amplifies ecological responses. This study evaluated the effects of the extremely dry 2015–2016 El Niño period on hydrological patterns and zooplankton dynamics in this shallow tropical estuary. Eight sampling campaigns were conducted, with water and zooplankton samples analyzed using standard methods. Salinity, dissolved inorganic nutrients, and chlorophyll-a concentrations were affected by the marked decrease in rainfall caused by the El Niño event. These changes significantly impacted zooplankton community dynamics, especially the densities of marine-estuarine species <i>Acartia lilljeborgii</i>, <i>Euterpina acutifrons</i>, and <i>Oikopleura dioica</i>, which peaked during months of highest salinity. High recruitment of copepod larval stages was also observed, with peak densities coinciding with dominant adult forms. In contrast, coastal and estuarine species such as <i>Acartia tonsa</i>, <i>Pseudodiaptomus marshi</i>, <i>Oithona oswaldocruzi</i>, and <i>Oithona hebes</i> were negatively affected by reduced rainfall. Species richness, diversity, and evenness during the El Niño period were relatively high compared to previously reported values under normal conditions in the same ecosystem. Environmental and temporal variables accounted for over half the variance in predominant taxa density, indicating that El Niño–driven changes influenced zooplankton structure over time. This suggests that El Niño may have strong impacts at the secondary trophic level, likely to cascade throughout the estuarine food web, altering its dynamics and the flow of carbon and energy through the system.

Anna Fricke, Germán A. Kopprio, Marianela Gastaldi et al.

Cultural eutrophication caused by human activity significantly impacts benthic ecosystems. This study investigated how different phytobenthic components—rhodophyte germlings, mesoalgal and macroalgal assemblages, and <i>Ulva</i> cf. <i>lactuca</i>—respond to nutrient enrichment in a tidal channel system in San Antonio Bay, Argentina. Two experiments were conducted: one in spring examined the interaction between nutrient enrichment (N + P, N + P + Fe) and grazing pressure on early and established algal communities, and the other in autumn assessed nutrient effects on assemblages and <i>Ulva</i> cf. <i>lactuca</i>. Results showed that early successional stages, such as germlings and mesoalgae, responded most strongly to nutrient inputs, while mature macroalgae remained largely unaffected. Significant growth of mesoalgae, with increased pigment concentrations (chlorophyll a, c, and carotenoids), occurred at the eutrophied SAO Channel in spring. Nutrient additions increased rhodophyte germlings but eventually reduced diatom-dominated mesoalgal growth. Mature macroalgae showed site-specific differences but did not respond to fertilization. Grazing effects were evident in treatments with protective cages, suggesting herbivory influences early-stage algal development. Overall, the study emphasizes the importance of the successional stage, grazing pressure, and environmental nutrient history in shaping benthic algal responses to eutrophication, offering key insights into the dynamics of coastal ecosystems under increasing nutrient stress.

Hanyu Zhang, Xia Li, Jingjiang Li et al.

Estuaries are irreplaceable ecological habitats and the primary deposition areas for sediment and pollutants from rivers. However, many estuaries are subject to an elevated risk of soil erosion owing to the increasing occurrence of flood events and reduced sediment supply. Soil erosion resistance in estuaries, as one of the most important parameters to assess and model soil erosion in estuaries, remains unclear. In this study, soil samples were collected from eight estuaries in Laizhou Bay, China, to characterize soil erosion resistance using soil erodibility (Kd) and soil critical shear stress (τc); additionally, the controlling soil properties were identified using a partial least-squares regression (PLSR) model. The Kd of the eight estuaries ranged from 15.21 to 772.08 cm3/N s. The τc of the eight estuaries ranged from 0.33 to 3.35 Pa. The results of the PLSR analysis indicated that the increased soil electrical conductivity at 25 °C water temperature (EC25), exchangeable sodium (Na+), and clay content contributed to high Kd values, whereas increased exchangeable calcium (Ca2+) and exchangeable potassium (K+) levels were correlated with low Kd values. The τc was negatively correlated with clay content, EC25, exchangeable magnesium (Mg2+), silt content, and total porosity and positively correlated with sand content, K+, and soil bulk density. The Di River estuary exhibited the highest EC25 and lowest Ca2+ among all the estuaries, resulting in the largest Kd. The Bailang River estuary exhibited the highest τc owing to its having the lowest Mg2+ content. These findings indicate that soil erosion resistance is not determined by any individual soil property; future studies should consider the interactions among the physical, chemical, and biological properties of soil.

Weiming Wu, Ruihua Nie, Kai Wei et al.

Sediment flux of many rivers has been significantly reduced due to human activities caused by economic development, leading to increasingly severe riverbed degradation. To prevent riverbed degradation, grade control structures (GCSs) have been widely applied in degrading channels. Existing studies have not provided a good understanding of the effects of GCSs on flow characteristics and bed morphology in degrading channels, limiting the management of degrading channels. A series of flume tests with no sediment supply are conducted to investigate the effects of GCSs on upstream water levels and riverbed morphology in degrading channels. The experimental results indicate that: (1) in the initial stage of degradation, the water surface slope in the backwater reach is linearly and negatively correlated with the GCS-height Froude number, based on the average flow velocity upstream of the backwater reach due to GCS and the height of GCS; (2) the effective protection bed length upstream of GCS is approximately equal to the length of the reach where the flow velocity is less than the critical velocity for sediment motion in the backwater zone; (3) for sequential GCSs, the effective protection bed length will decrease if GCS is located in the backwater reach of the downstream GCS. A semi-analytical calculation method of the effective protection length and equilibrium bed profile upstream of GCS in degrading channels is proposed based on the critical condition of sediment motion and weir flow formulas. The computed values by the proposed calculation method agree well with the experimental data of the present study.

Hayato Ishida, Amal Elsokary, Maria Aslam et al.

Realisation of significant advances in capabilities of sensors, computing, timing, and communication enabled by quantum technologies is dependent on engineering highly complex systems that integrate quantum devices into existing classical infrastructure. A systems engineering approach is considered to address the growing need for quantum-secure telecommunications that overcome the threat to encryption caused by maturing quantum computation. This work explores a range of existing and future quantum communication networks, specifically quantum key distribution network proposals, to model and demonstrate the evolution of quantum key distribution network architectures. Leveraging Orthogonal Variability Modelling and Systems Modelling Language as candidate modelling languages, the study creates traceable artefacts to promote modular architectures that are reusable for future studies. We propose a variability-driven framework for managing fast-evolving network architectures with respect to increasing stakeholder expectations. The result contributes to the systematic development of viable quantum key distribution networks and supports the investigation of similar integration challenges relevant to the broader context of quantum systems engineering.

Tomi Suomi, Petri Ihantola, Tommi Mikkonen et al.

Agile software development relies on self-organized teams, underlining the importance of individual responsibility. How developers take responsibility and build ownership are influenced by external factors such as architecture and development methods. This paper examines the existing literature on ownership in software engineering and in psychology, and argues that a more comprehensive view of ownership in software engineering has a great potential in improving software team's work. Initial positions on the issue are offered for discussion and to lay foundations for further research.

Mark R. Jury

Southwestern Peru has an arid climate typical of subtropical west coasts bordering cold ocean currents. Mountain runoff is barely able to sustain urban needs and motivates this research. Using high-resolution satellite reanalysis products, the meso-scale climate and weather variability are explored via point-to-field regression. A time series spanning 1970–2022 of Tacna area (18 S, 70.2 W, 570 m) rainfall, potential evaporation, wind, and weather parameters were evaluated for thermodynamic and kinematic features. Although sea breezes draw marine air inland, they simultaneously generate low-level divergence and subsidence aloft. Potential evaporation in early summer causes water deficits that are rarely offset by late summer runoff from the Andes Mountains. Winter (May–September) showers from passing cold fronts are more frequent during El Niño. Warming of the tropical east Pacific accelerates subtropical westerly winds that lift over the coastal plains. Quasi-stationary Rossby wave patterns amplify transient troughs at 70 W, but the winter showers rarely exceed 4 mm/day due to low-level stability from negative heat fluxes over cool seawater offshore. Two winter wet spells were studied using satellite and surface data (July 2002, July 2009). Light showers were prominent in elevations from 400 to 900 m. An early summer dry spell was considered (November 2020), wherein southeast winds, coastal upwelling, and low dewpoint temperatures coincided with La Niña conditions. A rain-gauge transect showed that summer convection stays east of the Andes escarpment and seldom benefits the coastal plains. Thus, water resources in Tacna are strained beyond the carrying capacity.

Dezhi Ran, Mengzhou Wu, Wei Yang et al.

By treating data and models as the source code, Foundation Models (FMs) become a new type of software. Mirroring the concept of software crisis, the increasing complexity of FMs making FM crisis a tangible concern in the coming decade, appealing for new theories and methodologies from the field of software engineering. In this paper, we outline our vision of introducing Foundation Model (FM) engineering, a strategic response to the anticipated FM crisis with principled engineering methodologies. FM engineering aims to mitigate potential issues in FM development and application through the introduction of declarative, automated, and unified programming interfaces for both data and model management, reducing the complexities involved in working with FMs by providing a more structured and intuitive process for developers. Through the establishment of FM engineering, we aim to provide a robust, automated, and extensible framework that addresses the imminent challenges, and discovering new research opportunities for the software engineering field.

Saeed Saviz Naeini, Reda Snaiki

Storm surge and waves are responsible for a substantial portion of tropical and extratropical cyclones-related damages. While high-fidelity numerical models have significantly advanced the simulation accuracy of storm surge and waves, they are not practical to be employed for probabilistic analysis, risk assessment or rapid prediction due to their high computational demands. In this study, a novel hybrid model combining dimensionality reduction and data-driven techniques is developed for rapid assessment of waves and storm surge responses over an extended coastal region. Specifically, the hybrid model simultaneously identifies a low-dimensional representation of the high-dimensional spatial system based on a deep autoencoder (DAE) while mapping the storm parameters to the obtained low-dimensional latent space using a deep neural network (DNN). To train the hybrid model, a combined weighted loss function is designed to encourage a balance between DAE and DNN training and achieve the best accuracy. The performance of the hybrid model is evaluated through a case study using the synthetic data from the North Atlantic Comprehensive Coastal Study (NACCS) covering critical regions within New York and New Jersey. In addition, the proposed approach is compared with two decoupled models where the regression model is based on DNN and the reduction techniques are either principal component analysis (PCA) or DAE which are trained separately from the DNN model. High accuracy and computational efficiency are observed for the hybrid model which could be readily implemented as part of early warning systems or probabilistic risk assessment of waves and storm surge.

Rudrajit Choudhuri, Ambareesh Ramakrishnan, Amreeta Chatterjee et al.

Generative AI (genAI) tools (e.g., ChatGPT, Copilot) have become ubiquitous in software engineering (SE). As SE educators, it behooves us to understand the consequences of genAI usage among SE students and to create a holistic view of where these tools can be successfully used. Through 16 reflective interviews with SE students, we explored their academic experiences of using genAI tools to complement SE learning and implementations. We uncover the contexts where these tools are helpful and where they pose challenges, along with examining why these challenges arise and how they impact students. We validated our findings through member checking and triangulation with instructors. Our findings provide practical considerations of where and why genAI should (not) be used in the context of supporting SE students.