Williams, H., 2018. Assessing the effectiveness of coastal foredune barriers in reducing hurricane washover sedimentation.

This study tests the effectiveness of physical barriers in blocking or reducing washover sedimentation in coastal marshes. It is widely assumed that natural and artificial physical barriers, such as foredunes and roads, block or reduce storm overwash. However, there appears to be little documented assessment of this effect. This topic has gained significance recently because of concerns over sea-level rise induced by global warming creating a larger potential threat from storm overwash. Nearshore physical barriers act to protect populations and infrastructure farther inland from storm surge, but they may also reduce sediment delivery to coastal marshlands, slowing their vertical accretion and contributing to their submergence by rising sea level. Consequently, there is a critical need for more information on the effect of physical barriers on marsh sedimentation. Washover sediment beds were examined along two transects across marshes in McFaddin National Wildlife Refuge in southeastern Texas, one in the lee of a higher and wider foredune barrier and one where foredunes are lower and narrower. Washover sediment beds deposited by Hurricanes Rita (2005) and Ike (2008) were found on both transects. Comparison of washover sedimentation along the two transects showed an average 40% reduction in sediment volume and an average reduction in inland extent of deposits of 505 m in the lee of the higher and wider barrier. These results show that even relatively subtle increases in barrier dimensions can cause substantial reductions in the magnitude of washover sedimentation in marshes. These findings have implications for paleotempestology studies that use the magnitude of washover sedimentation in the lee of dynamic coastal barriers as geologic proxies of storm intensity. Coastal management agencies contemplating the use of physical barriers to block storm surge should take into consideration the impact of such barriers on the sustainability of coastal marshes faced with rising sea level.

Díez, J.; Cohn, N.; Kaminsky, G.M.; Medina, R., and Ruggiero, P., 2018. Spatial and temporal variability of dissipative dry beach profiles in the Pacific Northwest, U.S.A.

Dissipative beaches in the U.S. Pacific Northwest are subject to a marked seasonality in wave climate and water levels, which leads to periodic oscillations in the morphology of the typically dry part of the beach profile. The back-and-forth, seasonal sediment exchange between the emerged and submerged parts of the beach system induces two main dry-beach profile-equilibrium configurations. During approximately 70% of the year, the dry beach adapts its configuration to a uniform positive slope from the mean high-water level to the dune toe. The remaining 30% of the time, typically corresponding to summer, the profile adopts a berm-like profile. These changes are quantified by studying intra-annual and interannual variations of the dry-beach profile shape. For intra-annual variations, a monthly profiling campaign between July 2014 and October 2015 from South Beach State Park (Oregon) was used. For interannual variations, 17 years (1997–2015) of quarterly beach profiles at 31 transects spread along the four subcells that constitute the Columbia River littoral cell were used. Several morphological phenomena have been identified via the application of two data-mining routines: the K-means clustering technique (KMA) and empirical orthogonal functions (EOFs). KMA clustering illustrates the main equilibrium configurations that the dry-beach profile experiences over time, whereas the EOF analysis explains the variability of the data in space and time. These analyses allow for examinations of berm formation and destruction as well as the shifting of the profile between summer/winter configurations—among other changes induced by the cross-shore sediment exchange, such as beachface and dune toe erosion and recovery.

Godoy, M.D.P.; Meireles, A.J.A., and Lacerda, L.D., 2018. Mangrove response to land use change in estuaries along the semiarid coast of Ceará, Brazil.

Mangroves cover an estimated area of approximately 12 to 20 million ha worldwide and serve as protection for the coastline from erosion and flooding. Nearly 70 mangrove species are considered endangered and could disappear in the next decade, which would have devastating economic and environmental consequences for coastal communities because of their ecological and economic importance. The annual rate of disappearance of coastal ecosystems is four times greater than the rate of the disappearance of rain forests. Mangroves suffer great pressure from the rapid conversion of forests into agricultural and urban areas, and, in these scenarios, climate change promotes specific pressures on mangroves and may increase the effects of anthropogenic activities. The focus of this study was to map the changes in mangrove areas in six river estuaries in Ceará, northeastern Brazil, between the years 1992 and 2011 and identify the main drivers of these changes. The results showed an increase in mangrove areas of five estuaries, while one estuary showed a decrease in mangrove area. Changes in river output capacity and sediment accumulation in the estuaries were associated with dam construction in the watersheds and can be responsible for new upstream mangrove areas in newly formed islands and along river banks. Abandoned saltpans also contributed to expansion of the mangrove areas. Deforestation for the construction of shrimp farms was the main cause of decreases in mangrove area, especially in the Pirangi estuary.

Chen, Q. and Ma, K., 2018. Determining whether exotic cordgrass (Spartina alterniflora) attracts carnivorous macrobenthic fauna within a Zhanjiang (China) mangrove ecosystem.

The last decade witnessed a paradigm shift concerning the impact of functional diversity on ecosystem functioning, and biological invasions have led to profound effects on functional diversity. However, a comprehensive understanding of the effects of exotic plants on macrobenthic functional diversity is not available for mangrove ecosystems. The macrobenthic functional feeding groups were compared in (1) a noninvaded stand vs. an Spartina alterniflora-invaded stand of the mangrove tree Avicennia marina (a mixture of A. marina and S. alterniflora) and (2) a noninvaded unvegetated shoal vs. an invaded shoal (a S. alterniflora monoculture) in Zhanjiang, China. The results indicated that the phytophagous group was the dominant functional feeding group regardless of habitat or macrobenthic parameter (species richness, abundance, and biomass) percentages. For all macrobenthic parameters, the carnivorous percentages were significantly higher in the S. alterniflora and A. marina mixture than in the A. marina monoculture. Except for species richness, the same was true for the S. alterniflora monoculture compared to the unvegetated shoal. The presence of the exotic cordgrass S. alterniflora is likely to attract more carnivorous macrobenthic fauna in a Zhanjiang mangrove ecosystem. Further analysis revealed that the sediment silt and plant density were the principal environmental variables determining the composition proportion of macrobenthic functional feeding groups. The lower sediment silt proportion and higher plant density ascribed to S. alterniflora invasions might be responsible for the changes in the proportion of macrobenthic functional feeding groups. The results aid the understanding of the effects and mechanisms of plant invasions on benthic functional diversity of mangrove ecosystems and yield insights into the links of biological invasions, functional diversity, and ecosystem functioning in coastal ecosystems.

Santana, R.; Teixeira, C., and Lessa, G., 2018. The impact of different forcing agents on the residual circulation in a tropical estuary (Baía de Todos os Santos, Brazil).

This study investigated the forcing of the residual circulation in a tropical estuary, Baía de Todos os Santos, Brazil (BTS). A numerical model (Regional Ocean Modeling System), forced with climatological means, was used to investigate the seasonal roles of the tide, wind, net heat, surface water fluxes, and river discharge on the residual circulation. The tide is the main driver of the circulation and its residual flow is structured at the bay mouth with a net-landward flow in the channel center and a net-seaward flow on the shoulders. The addition of wind drag affected the surface circulation, forcing W-bound (N-bound) currents in the spring–summer (fall–winter) months and generating a positive sea-level slope toward the continent. The addition of heat and surface water fluxes to the simulation established an incipient gravitational circulation, mainly because of the large (approximately 0.2°C/km) temperature gradients in the summer. The river discharge, added last, was second to the tide in driving the residual circulation in the BTS and established the gravitational circulation through most of the bay, including the bay mouth. The residual velocities attained magnitudes smaller than 0.13 ms⁻¹ in the main channel and were seasonally controlled, with stronger currents during the summer when the river discharge peaked. The onset of the baroclinic forcing (heat and surface water fluxes plus river discharge) reduced the e-folding flushing time by a factor of five relative to the experiment with barotropic forcing (wind and tides) only.

Trepanier, J.C.; Needham, H.F., and Ellis, K.N., 2018. Understanding the influence of tropical cyclone landfall central pressure and accumulated rainfall on storm surge near New Orleans, Louisiana.

Tropical cyclone track, landfall central pressure, accumulated cyclone rain, and storm surge are assessed for five stations surrounding Lake Pontchartrain in Louisiana: Shell Beach, the New Orleans Lakefront, Frenier, Mandeville, and Slidell. Floods from 1901–2012 are analyzed for cases in which the event tracks, the landfall central pressure, the amount of inland flooding from precipitation, and the storm-surge inundation all lead to compound effects, as in Hurricane Katrina (2005) and Hurricane Isaac (2012). Data are from U-Surge, the National Hurricane Center, and the National Weather Service Cooperative Observer Program. A storm track climatology is provided showing the average track for all events and for events that reached at least 43 m s⁻¹. The intense storms have a more concentrated track and approach from the south. Correlation and multivariate linear regression were used to evaluate the relationship among landfall central pressure, accumulated rainfall, and storm surge. For every 1 mbar increase in pressure when rainfall was held constant, the storm surge decreased by 0.024 m (p value <0.000). For every 1 mm of increase in rainfall when pressure was held constant, the storm surge increased by 0.006 m (0.0001). These two variables explain 63% of the variability in storm surge at this station. A percentage of change analysis from quantile regression was used to understand the amount of change in the storm surge based on the amount of change in the rainfall or the landfall central pressure. A small change in rainfall amounts or landfall central pressure can lead to a large change in the storm surge.

Zhang, J.; Tong, L.; Zheng, J.; He, R., and Guo, Y., 2018. Effects of soil resistance damping on wave-induced pore pressure accumulation around a composite breakwater.

It is important to consider the potential instability of the seabed from the accumulation of wave-induced pore pressure in the design of a composite breakwater because the pore pressure within the seabed can build up considerably under wave loading, which can eventually lead to a sharp decrease in its effective stress. Because of the importance in practical engineering, many theoretical models have been developed to evaluate the magnitude and distribution of residual pore pressure. However, most of these studies treat the soil skeleton as an invariant medium, which ignores the damping of the soil strength from the reduction in the effective stress. In this study, a two-dimensional poroelastoplastic model, in which the influence of the reduction of effective stress on soil strength was considered, is proposed for investigating the accumulation of pore pressure around a composite breakwater and its effect on soil characteristics. The simulation results show that liquefaction is likely to occur around the toe of the breakwater because of the accumulation of pore pressure at that point. The liquefaction leads to a decrease in soil resistance, which has a great effect on the development of the residual pore pressure. Analysis shows that the development of residual pore pressure is also greatly affected by both the wave height and soil permeability. The simulation demonstrates that if the decrease in soil resistance is not considered, the soil liquefaction depth will be overestimated.

de la Vega-Leinert, A.C.; Stoll-Kleemann, S., and Wegener, E., 2018. Managed realignment (MR) along the Eastern German Baltic Sea: A catalyst for conflict or for a coastal zone management consensus.

Managed Realignment (MR), which involves the removal of coastal defences or their relocation further inland, is a desirable option for demographically and economically marginal rural areas, from scientific, political and managerial perspectives. In Europe, MR is reshaping coastal landscapes, and, though not directly endangering lives, is affecting people's sense of safety and control over their land and livelihoods. This can elicit conflict, but also foster consensus. In this study, participatory qualitative research methods were used to investigate stakeholders' perceptions and preferences with regard to coastal land management strategies on the eastern German Baltic coast in the state of Mecklenburg–Western Pomerania. MR reflects a change in the way in which coastal land is valued, with supporting and regulating ecosystem services increasingly seen as critical for the resilience, conservation, amenity value and cost-efficient defence of coastal areas. Coastal defence is being redefined as a coastal land(scape) management task. The two contrasting case studies discussed show that, where public land is concerned, MR projects can be negotiated by, and provide benefits for, all parties concerned. Nevertheless, where local populations feel that they will be negatively affected, they may make use of democratic mechanisms to voice their dissent, organise resistance, and lobby to become negotiating parties in decisions concerning MR projects. If there is to be public consensus over the idea that coastal resilience is a common good, then the individual losses that result from such projects should be explicitly acknowledged and compensated for.

Pallikarakis, A.; Triantaphyllou, M.V.; Papanikolaou, I.; Dimiza, M.D.; Reicherter, K., and Migiros, G., 2018. Age constraints and paleoenvironmental interpretation of a borehole sedimentary sequence along the eastern part of the Corinth Isthmus, Greece.

Borehole Bh-3, located at the eastern part of the Corinth Isthmus (Greece) in a highly active extensional tectonic environment, is studied in detail. The lithology of the 70-m-long borehole is described, and 55 samples extracted from the core are analyzed for their micropaleontological content. Quantitative analysis of foraminiferal fauna assemblages, along with magnetic susceptibility measurements, indicates alternations between different paleoenvironments ranging from upper shoreface and fluvial-terrestrial to lagoon and shallow marine. The borehole site regional paleodepth was estimated, ranging from a few meters to ∼40 m on the basis of foraminiferal assemblages within the borehole, and the vertical stacking of the facies was interpreted as transgressive and regressive system tracts. Calcareous nannofossils found within the core, based on the presence of Emiliania huxleyi specimens, correlated with the glacioeustatic sea-level changes, and the uplift rate of the area indicated a post–240-ka age, corresponding to sea-level highstand marine isotope stages 7 to 5.

Mao, L. and Chen, Y., 2018. Analyzing the characteristics of ship-generated waves in an inland-restricted channel using an artificial neural network (ANN).

Many empirical formulas based on experimental data have been proposed using regression analysis to analyze characteristics of ship-generated waves for engineering applications. However, ship-generated waves have an inherent variability, which suggests that a traditional method such as regression analysis might be inadequate. This paper presents an alternative nonlinear method using an artificial neural network (ANN) for clarifying the characteristics of ship-generated waves in an inland-restricted channel. A three-layered feed-forward back-propagation network with six input variables, five hidden layer nodes, and one output variable is established to predict the maximum ship-generated wave height based on sets of data collected from field observations conducted in Xicheng Canal. Comparisons of the predicted results from the proposed model with observed data show that the maximum ship-generated wave height can be predicted more accurately using the ANN compared to the two empirical formulas. The proposed model was then used to analyze the quantitative relationship between maximum ship-generated wave height in Xicheng Canal and various impact factors. Maximum ship-generated wave heights for 500-ton and 800-ton ships are given for engineering design in Xicheng Canal. These results show that the ANN model is a useful tool for both the prediction and mechanistic analysis of ship-generated waves in an inland-restricted channel.

Xu, G.; Cai, C.S.; Han, Y.; Wu, C., and Xue, F., 2018. Numerical assessment of the wave loads on coastal twin bridge decks under Stokes waves.

In recent hurricane seasons, many coastal low-lying bridges along the Gulf of the Mexico in the United States have suffered huge damages, which has motivated many studies on the failure mechanisms of these coastal infrastructures. While in previous studies one single bridge deck is usually the focal structure type; this study, instead, addresses the features of the wave loads on coastal low-lying bridges with twin decks that are subject to Stokes waves, identifies the wave reflection effects in the twin bridge deck–wave interaction, and brings forward more questions for future studies on this topic. Based on the geometric parameters of the damaged Escambia Bay Bridge, the wave loads on single and twin bridge decks, considering different still water depths with various structure elevations, are compared first. The observed difference in the comparisons of the obtained wave loads shows that the wave reflection plays an important role in the twin bridge deck–wave interaction. Then, the effects of the deck gap between the twin decks of the bridge, the seaward deck and landward deck, are systematically investigated. Both the transverse/horizontal and the vertical wave loads under the prescribed wave conditions are analyzed in detail. The results not only confirm the expectation that the wave loads on the landward bridge deck are usually smaller than those on the seaward one, but also reveal that the wave loads on the twin bridge decks are correlated with the variable deck gap between the twin bridge decks. This study improves the understanding that the wave loads on twin bridge decks, rather than one single bridge deck, under periodical waves need to be quantitatively determined for engineering practices. This study also shows that the wave reflection effects should be appropriately considered on the future revision of the AASHTO code.

Vick, P.E.; Peterson, M.S.; Slack, W.T., and Grammer, P.O., 2018. Occupancy patterns of Gulf Sturgeon, Acipenser oxyrinchus desotoi, associated with Ship Island, Mississippi.

In order to reduce wave energy associated with tropical storms and hurricanes in the western Mississippi Sound, the Mississippi Coastal Improvements Program will close a 5.6 km breach (i.e. Camille Cut) separating East and West Ship Island, Mississippi, and restore sediments to the southern shoreline of East Ship Island. As part of this program, federally designated critical Gulf Sturgeon habitat associated with Ship Island was monitored to establish baseline patterns of use prior to island restoration using a passive acoustic array during overwintering periods from 2011 to 2014. Gulf Sturgeon of both western and eastern populations occupied the passes, cuts, and ends of Ship Island over the study period, but no difference in occupancy was observed among four initially established zones. However, when comparing the new most eastern zone, Dog Keys Pass, to the four initial zones, occupancy was four times greater in this zone than any other monitored zone, indicative of foraging behavior associated with high abundance of benthic resources. Reconnecting East and West Ship Island through filling Camille Cut proper may increase Gulf Sturgeon occupancy in Dog Keys Pass and other areas near the ends and passes of the barrier islands. The loss of Camille Cut proper as critical habitat may be partially augmented by “new” nearshore habitat north and south of Camille Cut; however, it is uncertain whether filling in Camille Cut will alter the physical components of the habitat, causing a shift in benthic prey availability and, thus, quality of forage habitat.

Liritzis, I.; Preka-Papadema, P.; Antonopoulos, P.; Kalachanis, K., and Tzanis, C.G., 2018. Does astronomical and geographical information of Plutarch's De Facie describe a trip beyond the North Atlantic Ocean?

In Plutarch's book On the Apparent Face in the Orb of the Moon, the interlocutors develop a dialogue about a trip to the “great continent” beyond the North Atlantic Ocean. By applying modern scientific data, the present reappraisal of the astronomical and geographical elements within this dialogue has produced a novel interpretation of the date and place of the meeting and a journey to the northern Atlantic Ocean. A described solar eclipse is dated to AD 75, making use of the National Aeronautics and Space Administration (NASA)/Espenak/Meeus list, as well as historical information. The described peculiar, recurrent trips take place every 30 years (when the planet Saturn reaches the Taurus constellation) from the Mediterranean Sea to the Cronian Open Sea, which is identified with northern Atlantic Ocean coasts. It has been suggested that the last mission had returned homeland in April AD 56. The information provided concerns, distances between coastal sites and islands, duration of sea paths in days, and the reported setting and size between the destination place and its gulf with regards to Azov (in Crimea) and the Caspian Sea. Implications of sea currents and the coastal geomorphology of those lands are given. Following strictly the Gulf Stream current, as well as other known sea currents in the northern Atlantic Ocean, and introducing estimated speed for the ship, the geographical location of destination of the Greek settlers is proposedly identified with St. Lawrence Gulf and Newfoundland island. Other unnamed islands mentioned in this dialogue are identified with Norway's islands, Azores, Iceland, Greenland, and Baffin islands. It has been shown that the journey is made with good knowledge of sea currents but by using bright stars and stellar configurations as astronomical nightscape markers that determine the exact orientation of the sailing toward the Iberian Peninsula and back to the eastern Mediterranean, making the current working hypothesis a plausible event.

Efremov, A.; Bolotova, Ya.; Mesterházy, A., and Toma, C., 2018. Features of distribution of Hydrilla verticillata (L. fil.) Royle (Hydrocharitaceae) in North Eurasia.

An assessment of Hydrilla verticillata (Hydrocharitaceae) distribution was made, with the involvement of a wide range of data (herbarium collections, Web resources, literature sources, and authors' observations), covering the period 1811–2016. It is shown that Hydrilla is a plurizonal macrothermal semicosmopolite species with many disjunctions in the geographical range. In the 20th century, H. verticillata expanded its secondary range significantly, primarily in North and South America (neocosmopolite). Within the primary range, in connection with high economic activities and development of transport, new invasion localities have appeared. For the European continent, H. verticillata should be considered a limitedly spreading naturalized neophyte (with the northern border at 55–56° N). In Northern Asia, H. verticillata can probably be considered a tertiary (Eocene) relict, which is currently allocated to the following enclaves: Central Asia–West Siberian, East Siberian (probably formed later), and the largest SE Asian habitats. The northern border of Hydrilla in the Asian continent lies along 56–58° N. Within the Asian part of the range the formation of new foci of infestation is currently observed, the species distribution is not controlled only by abiotic factors (temperature, length of vegetation period, hydrochemical features of the waterbodies), but also by biotic ones; there is a competition with the more aggressive neophyte Elodea canadensis.

Antunes do Carmo, J.S., 2018. Climate change, adaptation measures, and integrated coastal zone management: The new protection paradigm for the Portuguese coastal zone.

The efforts made to reduce the causes and mitigate the effects of global climate change continue to be critical in coastal areas. Many adaptation strategies implemented in coastal areas remain inadequate or ineffective. Using primarily events and interventions carried out along the Portuguese Atlantic coast, this work aims to show the paradigm shift that has occurred in Portugal since the last century (the 1990s) within the scope of the National Coastal Zone Management Strategy, taking into account the new guidelines for the implementation of coastal defence works. In this context, this paper also aims to assist coastal communities in carrying out operational coastal management by presenting and discussing management tools and primary options that should be considered in any adaptation programme that is to be implemented. Both nonstructural and structural measures are considered. Action plans, warning systems, emergency plans, and evacuation plans belong to the first category. Education and training are also considered, because they play a key role in the sustainability of coastal areas, especially in the coming generations. Structural measures are adaptation options that are designed to increase the safety of people and reduce risks. They are discussed and grouped into categories that include accommodation, protection, and retreat. Recent cases of successful accommodation and protection measures implemented along the Portuguese coast are also presented and discussed.

Seymour, A.C.; Ridge, J.T.; Rodriguez, A.B.; Newton, E.; Dale, J., and Johnston, D.W., 2018. Deploying fixed wing unoccupied aerial systems (UAS) for coastal morphology assessment and management.

Accurate measurement of the morphology and distribution of coastal habitats is critical for understanding the function of coastal environments, assessing the resilience of coastal communities, and managing the coastal zone effectively. Unoccupied aerial systems (UASs, also known as unmanned aerial vehicles) and structure from motion (SfM) photogrammetry may be optimal for coastal surveys around small- or medium-sized municipalities, but guidance is needed to identify appropriate equipment configurations. Digital surface models (DSMs) from UAS equipped with mapping and survey-grade GPS units were processed with and without ground control point (GCP) correction, and their accuracy was compared to terrestrial laser scanner (TLS) derived DSMs and global navigation satellite system (GNSS) checkpoints. Four UAS sorties were flown over an active fetch-limited barrier island in North Carolina, which was concurrently surveyed with TLS and GNSS. Average DSM vertical accuracy from real-time kinematic (RTK)-equipped UAS improved from 0.081 m error to 0.032 m error after GCP correction, and the average elevation range between surfaces improved from ∼0.17 m to ∼0.05 m. In areas with low dunes, the UAS DSM was an average of 0.042 m away from the TLS DSM and was closer to the GNSS survey checkpoints. In vegetated areas, this distance increased to 0.082 m because of TLS occlusion effects. The SfM process-generated elevation artifacts in areas of imagery with homogenous texture, such as the foreshore and sun angle, likely plays an important role when surveying sandy beach environments. The RTK-equipped UAS and UAS data processed with GCPs yield DMSs with similar accuracy to those derived from TLS but are a superior choice for municipal-scale surveys because of lower operating costs, greater areal coverage, and lower environmental impact.

Yin, Z.; Yang, X.; Liang, B.; Jin, L., and Ma, L., 2018. Experimental investigation of wave attenuation through flexible plants on a flat bed.

Plants can serve as a good form of coastal protection against wave wash. A series of physical experiments was conducted with various flexible plant arrangements under regular wave parameters, and the composite wave heights were measured both ahead of and behind the plants. Goda's method was used to resolve incident and reflected waves from the composite waves, from which the wave transmission coefficient and the dissipated energy ratio were obtained. It was observed that the wave transmission coefficient decreased with increasing relative number of plant rows, increasing relative density of plants, and increasing relative wave height and wave steepness. The wave transmission coefficient increased with an increasing wave period T < 2.00 s; however, it decreased with an increasing wave period T ≥ 2.00 s. In contrast, the dissipated energy ratio was disproportionate to the wave transmission coefficient. Dimensional analysis and the least squares method were used to obtain the wave transmission coefficient and the dissipated energy ratio formulas, and they agreed well with the experimental data. This study provided insight into plant revetment engineering at the coastal zone.

Song, D.; Guo, T.; Sun, W.; Jiang, Q., and Yang, H., 2018. Using an active disturbance rejection decoupling control algorithm to improve operational performance for underwater glider applications.

The underwater glider is a large time-delaying, time-varying, nonlinear, and strong coupling control system that allows for various submarine environmental monitoring applications. To solve the coupling problem between pitch angle and velocity, improve control accuracy, and reduce settling time for energy consumption for the glider, a dynamic surface decoupling control (DSDC) algorithm based on the active disturbance rejection control (ADRC) is described in this paper. By importing the dynamic surface decoupling control law and first-order low-pass filter to improve control precision and reduce the number of calculations, a decoupling algorithm based on ADRC was used to solve the coupled control problem for an underwater glider. Combining the mathematical equation for motion and the kinematic equation for an underwater glider, the DSDC-ADRC algorithm was implanted into the controller. Simulation tests and sea trials showed that it reduced overshoot by 20% and had a 100 s settling time compared with the proportion, integration, and differentiation (PID) algorithm. Sea trials indicated that the decreased overshoot and settling time could save 23% battery energy, which would extend the sail distance 29.9% further than before.

Habib, E.; Deshotel, M., and Williams, D., 2018. Unlocking the educational value of large-scale, coastal-ecosystem restoration projects: Development of student-centered, multidisciplinary learning modules.

Recent decades have witnessed the development and implementation of several regional-scale, coastal-restoration planning projects that deal with human–natural coupled ecosystems. With their rich contexts, societal importance and preavailable data and modeling resources, these projects offer unique, multidisciplinary learning opportunities that are yet to be tapped into, especially at the undergraduate level. The current study presents an effort to capitalize on these regional-scale projects and use their resources in undergraduate educational settings. The study describes the development of a set of Web-based learning modules that are situated in the Chenier Plain coastal ecosystem in Louisiana. Going through a comprehensive. coast-wide restoration-planning effort, coastal Louisiana is a unique ecosystem that captures the interactions between inland hydrology and coastal and wetland processes. Centered on the current crisis of coastal land loss in the region, the modules immerse students in a suite of active-learning experiences in which they prepare and analyze data, reproduce model simulations, interpret results, and balance the beneficial and detrimental impacts of several real-world coastal-restoration projects. The modules cover a wide array of topics, including system-scale analysis of water and salt budgets, use of numerical models in coastal hydrologic settings, linkages between hydrologic variability and vegetation regimes, and assessments of different restoration strategies. The article presents lessons learned, challenges, and students' perspectives from pilot classroom implementations to guide similar future efforts on using large-scale, coastal-ecosystem projects to enrich current educational practices in the field of coastal hydrology and other related topics.

Zheng, S.; Wang, A.; Mehmood, F., and Mohmand, Y.T., 2018. An improved path optimum algorithm for container relocation problems in port terminals worldwide.

The container relocation problem (CRP) for ports worldwide has been a highly significant research topic because of its contribution to the improvement of yard-running efficiency. It can be defined as a sequence that allows each container to be extracted with the least number of relocations when identical containers in a cluster have been stacked in a block. This study differs from previous research mainly in five aspects: (1) a two-level goal programming model for CRP is presented that can help in understanding of this problem and provide a solid theoretical ground for this research; (2) because of the NP time hardness of the CRP, heuristic rules are proposed to reduce hunting space by the way of dividing solution space; (3) an improved path optimum algorithm (I-POA) is proposed to reduce unfeasible solutions and find a high-quality solution for any three-dimensional case in a shorter running time; (4) the numerical experiments show that the algorithm proposed in this research achieves better performance than similar algorithms because of its higher levels of efficiency and more robust property; and (5) a general expression for the utilization level of the storage area and the number of relocations is proposed to check the reliability of the result by conducting a sensitivity analysis. Based on this research, the following conclusion can be obtained: I-POA possesses significant practical value in the improvement of intelligent resource scheduling standards of coastal container ports worldwide.