scholarly journals Modelling Cross-Shore Shoreline Change on Multiple Timescales and Their Interactions

2021 ◽  
Vol 9 (6) ◽  
pp. 582
Author(s):  
Rob Schepper ◽  
Rafael Almar ◽  
Erwin Bergsma ◽  
Sierd de de Vries ◽  
Ad Reniers ◽  
...  
Keyword(s):  
Shoreline Change ◽  
Sandy Beaches ◽  
Data Driven ◽  
Short Term ◽  
New Approach ◽  
Multiple Timescales ◽  
Direct Forcing ◽  
Shoreline Prediction ◽  
Study Sites

In this paper, a new approach to model wave-driven, cross-shore shoreline change incorporating multiple timescales is introduced. As a base, we use the equilibrium shoreline prediction model ShoreFor that accounts for a single timescale only. High-resolution shoreline data collected at three distinctly different study sites is used to train the new data-driven model. In addition to the direct forcing approach used in most models, here two additional terms are introduced: a time-upscaling and a time-downscaling term. The upscaling term accounts for the persistent effect of short-term events, such as storms, on the shoreline position. The downscaling term accounts for the effect of long-term shoreline modulations, caused by, for example, climate variability, on shorter event impacts. The multi-timescale model shows improvement compared to the original ShoreFor model (a normalized mean square error improvement during validation of 18 to 59%) at the three contrasted sandy beaches. Moreover, it gains insight in the various timescales (storms to inter-annual) and reveals their interactions that cause shoreline change. We find that extreme forcing events have a persistent shoreline impact and cause 57–73% of the shoreline variability at the three sites. Moreover, long-term shoreline trends affect short-term forcing event impacts and determine 20–27% of the shoreline variability.

scholarly journals Challenges and Opportunities in Coastal Shoreline Prediction

2021 ◽  
Vol 8 ◽  
Author(s):  
Kristen D. Splinter ◽  
Giovanni Coco
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Shoreline Change ◽  
Sandy Beaches ◽  
Water Levels ◽  
Current State ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Shoreline Prediction

Sandy beaches comprise approximately 31% of the world's ice-free coasts. Sandy coastlines around the world are continuously adjusting in response to changing waves and water levels at both short (storm) and long (climate-driven, from El-Nino Southern Oscillation to sea level rise) timescales. Managing this critical zone requires robust, advanced tools that represent our best understanding of how to abstract and integrate coastal processes. However, this has been hindered by (1) a lack of long-term, large-scale coastal monitoring of sandy beaches and (2) a robust understanding of the key physical processes that drive shoreline change over multiple timescales. This perspectives article aims to summarize the current state of shoreline modeling at the sub-century timescale and provides an outlook on future challenges and opportunities ahead.

“The Death of Liberal Internationalism?: Donald Trump, Walmart, and the Two Koreas”

2018 ◽  
Vol 25 (2) ◽  
pp. 169-197
Author(s):  
Mitchell B. Lerner
Keyword(s):  
United States ◽  
The United States ◽  
Business Practices ◽  
Short Term ◽  
New Approach ◽  
Liberal Internationalism ◽  
The People ◽  
Modern Business ◽  
Short Time

The election of Donald J. Trump unsettled many areas of U.S. foreign policy, but few more than the nation’s relationship with Korea. This article argues that the Trump administration’s vision for the world represents a stark break from the tradition of liberal internationalism and instead seeks to take the United States down a path that reflects the modern business practices of giant American corporations. A suitable label for this vision, as the following pages will show, is “Walmart unilateralism.” This framework abandons the traditional American policies of nation building and alliances based on shared ideological values. Instead, it embraces a more short-term approach rooted in financial bottom lines, flexible alliances and rivalries, and the ruthless exploitation of power hierarchies. This new approach, this article concludes, may dramatically transform the American relationship with Korea. Walmart unilateralism in Korea almost certainly will have some short-time positive ramifications for the United States, but its larger failure to consider the history and values of the people living on the Korean Peninsula may generate serious long-term problems for the future experience of the United States in the region.

scholarly journals Rapid retreat of permafrost coastline observed with aerial drone photogrammetry

2019 ◽  
Vol 13 (5) ◽  
pp. 1513-1528 ◽  
Author(s):  
Andrew M. Cunliffe ◽  
George Tanski ◽  
Boris Radosavljevic ◽  
William F. Palmer ◽  
Torsten Sachs ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Average Rate ◽  
Temporal Frequency ◽  
Shoreline Change ◽  
Yukon Territory ◽  
Aerial Photographs ◽  
The Arctic ◽  
Storm Events ◽  
Short Term

Abstract. Permafrost landscapes are changing around the Arctic in response to climate warming, with coastal erosion being one of the most prominent and hazardous features. Using drone platforms, satellite images, and historic aerial photographs, we observed the rapid retreat of a permafrost coastline on Qikiqtaruk – Herschel Island, Yukon Territory, in the Canadian Beaufort Sea. This coastline is adjacent to a gravel spit accommodating several culturally significant sites and is the logistical base for the Qikiqtaruk – Herschel Island Territorial Park operations. In this study we sought to (i) assess short-term coastal erosion dynamics over fine temporal resolution, (ii) evaluate short-term shoreline change in the context of long-term observations, and (iii) demonstrate the potential of low-cost lightweight unmanned aerial vehicles (“drones”) to inform coastline studies and management decisions. We resurveyed a 500 m permafrost coastal reach at high temporal frequency (seven surveys over 40 d in 2017). Intra-seasonal shoreline changes were related to meteorological and oceanographic variables to understand controls on intra-seasonal erosion patterns. To put our short-term observations into historical context, we combined our analysis of shoreline positions in 2016 and 2017 with historical observations from 1952, 1970, 2000, and 2011. In just the summer of 2017, we observed coastal retreat of 14.5 m, more than 6 times faster than the long-term average rate of 2.2±0.1 m a−1 (1952–2017). Coastline retreat rates exceeded 1.0±0.1 m d−1 over a single 4 d period. Over 40 d, we estimated removal of ca. 0.96 m3 m−1 d−1. These findings highlight the episodic nature of shoreline change and the important role of storm events, which are poorly understood along permafrost coastlines. We found drone surveys combined with image-based modelling yield fine spatial resolution and accurately geolocated observations that are highly suitable to observe intra-seasonal erosion dynamics in rapidly changing Arctic landscapes.

A Feasibility Investigation for Developing Artificial Beachrocks: A Potential Measure for Coastal Protection in Southeast Yogyakarta Coast, Indonesia

2020 ◽  
Author(s):  
Lutfian Rusdi Daryono ◽  
Kazunori Nakashima ◽  
Satoru Kawasaki ◽  
Koichi Suzuki ◽  
Anastasia Dewi Titisari ◽  
...  
Keyword(s):  
Physical And Mechanical Properties ◽  
Sandy Beaches ◽  
Coastal Sediments ◽  
Coastal Protection ◽  
Optimum Conditions ◽  
Short Term ◽  
Resistivity Survey ◽  
Wave Effects ◽  
Potential Measure

<p>Erosion prone sandy beaches are frequently covered by cement and mortar to preserve the coastal zone, but the conventional approach has an adverse impact on the environment, altering the coastal landscape and processes unfavorably. The term “beachrock” refers to cemented coastal sediments through a long-term formation of CaCO<sub>3</sub> cement, and which is an important feature in many tropical coastlines as it appears to have a substantial anchoring effect against wave effects and erodibility. Therefore, the objective of this study is to evaluate the feasibility in progressing the formation of artificial beachrocks using natural materials (e.g., microbes, sand, shell, pieces of coral, and seaweed etc.) within a short-term, and to introduce the method as a novel candidate for coastal protection. In this study, both resistivity survey and multi analysis seismic wave (MASW) survey along the same lines were performed at first to elucidate the subsurface structure of existing beachrocks in the Southeast Yogyakarta coastal area (Indonesia), followed by the laboratory analysis, which is aimed understand the basics in the formation mechanism. Peloidal micrite cement, the cement comprised of aragonite needles, micritized granules and the cover of micritic were observed in natural beachrocks. Mimicking the mechanism, an attempt has been undertaken to develop artificial beachrocks in the laboratory via microbial induced carbonate precipitation (MICP). Finally, the physical and mechanical properties were well compared between the artificially formed beachrocks and natural beachrocks collected from the survey lines. The results suggest that the artificial deposits treated for 14 days under optimum conditions, achieved a peak unconfined compressive strength of around 6 MPa similar to that of weak-consolidated natural beachrock. The comparison further reveals that the variables such as porosity, Vp, Vs, and strength are primarily rely on the precipitated morphology of the crystals.</p>

Unified Pressure and Rate Transient Analysis of Production and Shut-in Data from Fractured Horizontal Wells

2021 ◽  
Author(s):  
HanYi Wang ◽  
Mukul Sharma ◽  
Harold McGowen
Keyword(s):  
Transient Analysis ◽  
Continuous Production ◽  
Short Term ◽  
New Approach ◽  
Step Rate ◽  
Bottom Hole ◽  
Rate Transient Analysis ◽  
Formation Pore Pressure ◽  
Fractured Horizontal Wells

Abstract Market-induced production shut-downs and restarts offer us an opportunity to gather step-rate and shut-in data for pressure transient analysis (PTA) and rate transient analysis (RTA). In this study, we present a unified transient analysis (UTA) to combine PTA and RTA in a single framework. In this new approach continuous production data, step-rate data, shut-in data and re-start data can be visualized and analyzed in a single superposition plot, which can be used to estimate both Afk and infer formation pore pressure in a holistic manner by utilizing all available data. Most importantly, we show that traditional log-log and square root of time plots can lead to false interpretation of the termination of linear-flow or power-law behavior. Field cases are presented to demonstrate the superiority of the newly introduced superposition plot, along with discussion on the calibration of long-term bottom-hole pressure with short-term measurements.

Local Water Politics

2016 ◽  
Author(s):  
Sara Hughes ◽  
Megan Mullin
Keyword(s):  
Local Level ◽  
Financial Sustainability ◽  
Local Institutions ◽  
Short Term ◽  
Water Politics ◽  
New Approach ◽  
The Past ◽  
Local Water ◽  
Over Time

Decentralization in water management authority has shifted decision-making to the local level and expanded participation to include a wider set of actors. The result is a politics of water that is more variable than in the past, across space and over time, reflecting the diversity of local values and local water resources. Fragmentation of policy responsibility offers potential for more environmental and financial sustainability in the long term, but in the short term it requires management agencies and stakeholders to find ways to interact effectively. How we design our local institutions, and the incentives that higher levels of government provide for directing local decisions, will help determine whether the new approach produces a more sustainable and resilient water future.

scholarly journals Detecting Nuisance Calls over Internet Telephony Using Caller Reputation

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 353
Author(s):  
Ibrahim Tariq Javed ◽  
Khalifa Toumi ◽  
Fares Alharbi ◽  
Tiziana Margaria ◽  
Noel Crespi
Keyword(s):  
Security Risk ◽  
False Detection ◽  
Short Term ◽  
New Approach ◽  
Call Duration ◽  
Internet Telephony ◽  
Proposed Model ◽  
Different Types ◽  
Reputation Model

Internet telephony permit callers to manage self-asserted profiles without any subscription contract nor identification proof. These cost-free services have attracted many telemarketers and spammers who generate unsolicited nuisance calls. Upon detection, they simply rejoin the network with a new identity to continue their malicious activities. Nuisance calls are highly disruptive when compared to email and social spam. They not only include annoying telemarketing calls but also contain scam and voice phishing which involves security risk for subscribers. Therefore, it remains a major challenge for Internet telephony providers to detect and avoid nuisance calls efficiently. In this paper, we present a new approach that uses caller reputation to detect different kinds of nuisance calls generated in the network. The reputation is computed in a hybrid manner by extracting information from call data records and using recommendations from reliable communicating participants. The behavior of the caller is assessed by extracting call features such as call-rate, call duration, and call density. Long term and short term reputations are computed to quickly detect the changing behavior of callers. Furthermore, our approach involves an efficient mechanism to combat whitewashing attacks performed by malicious callers to continue generating nuisance calls in the network. We conduct simulations to compute the performance of our proposed model. The experiments conclude that the proposed reputation model is an effective method to detect different types of nuisance calls while avoiding false detection of legitimate calls.

SINGLE-MARKET REGULATION AND INNOVATION IN EUROPE'S MEDICAL DEVICES INDUSTRY

2001 ◽  
Vol 17 (3) ◽  
pp. 421-432 ◽  
Author(s):  
Horst Steg ◽  
Nikolaus Thumm
Keyword(s):  
Medical Devices ◽  
Regulatory Framework ◽  
European Market ◽  
Market Regulation ◽  
Short Term ◽  
New Approach ◽  
Single European Market ◽  
The Impact ◽  
Total Impact

In this article we analyze the influence of the legal regulatory framework in Europe, established by the two directives on medical devices and active implantable devices, on the performance of innovation in a single European market. First, we describe in general the possible influence of a single European market on innovation and the institutional features of the particular harmonization approach (“New Approach”) we are looking at here. The empirical results presented derive from a survey investigation involving 150 firms that we defined as best innovators in the European medical devices industry from a pre-survey. The results confirm that the total impact of the New Approach regulation on firms' innovation in the long term is positive. However, it also becomes clear that the impact of regulation on innovation is limited if the factors are looked at individually and that there is a clear difference regarding short-term effects. To improve the regulatory framework, several policy actions are recommended.

scholarly journals Solar Irradiance Forecasting Using a Data-Driven Algorithm and Contextual Optimisation

2021 ◽  
Vol 12 (1) ◽  
pp. 134
Author(s):  
Paula Bendiek ◽  
Ahmad Taha ◽  
Qammer H. Abbasi ◽  
Basel Barakat
Keyword(s):  
Solar Irradiance ◽  
Contextual Information ◽  
Management Strategies ◽  
Energy Transition ◽  
Data Driven ◽  
Coefficient Of Determination ◽  
Support Vector ◽  
Short Term ◽  
Forecast Horizon

Solar forecasting plays a key part in the renewable energy transition. Major challenges, related to load balancing and grid stability, emerge when a high percentage of energy is provided by renewables. These can be tackled by new energy management strategies guided by power forecasts. This paper presents a data-driven and contextual optimisation forecasting (DCF) algorithm for solar irradiance that was comprehensively validated using short- and long-term predictions, in three US cities: Denver, Boston, and Seattle. Moreover, step-by-step implementation guidelines to follow and reproduce the results were proposed. Initially, a comparative study of two machine learning (ML) algorithms, the support vector machine (SVM) and Facebook Prophet (FBP) for solar prediction was conducted. The short-term SVM outperformed the FBP model for the 1- and 2- hour prediction, achieving a coefficient of determination (R2) of 91.2% in Boston. However, FBP displayed sustained performance for increasing the forecast horizon and yielded better results for 3-hour and long-term forecasts. The algorithms were optimised by further contextual model adjustments which resulted in substantially improved performance. Thus, DCF utilised SVM for short-term and FBP for long-term predictions and optimised their performance using contextual information. DCF achieved consistent performance for the three cities and for long- and short-term predictions, with an average R2 of 85%.

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