scholarly journals The Influence of Geostatistical Prior Modeling on the Solution of DCT-Based Bayesian Inversion: A Case Study from Chicken Creek Catchment

2019 ◽  
Vol 11 (13) ◽  
pp. 1549 ◽  
Author(s):  
Davood Moghadas ◽  
Jasper A. Vrugt
Keyword(s):  
Electrical Conductivity ◽  
Low Frequency ◽  
Geostatistical Simulation ◽  
Bayesian Inversion ◽  
Geophysical Measurement ◽  
Dct Coefficients ◽  
The Impact ◽  
Selection Of

Low frequency loop-loop electromagnetic induction (EMI) is a widely-used geophysical measurement method to rapidly measure in situ the apparent electrical conductivity (ECa) of variably-saturated soils. Here, we couple Bayesian inversion of a quasi-two-dimensional electromagnetic (EM) model with image compression via the discrete cosine transform (DCT) for subsurface electrical conductivity (EC) imaging. The subsurface EC distributions are obtained from multi-configuration EMI data measured with a CMD-Explorer sensor along two transects in the Chicken Creek catchment (Brandenburg, Germany). Dipole-dipole electrical resistivity tomography (ERT) data are used to benchmark the inferred EC fields of both transects. We are especially concerned with the impact of the DCT truncation method on the accuracy and reliability of the inversely-estimated EC images. We contrast the results of two different truncation approaches for model parametrization. The first scenario considers an arbitrary selection of the dominant DCT coefficients and their prior distributions (a commonly-used approach), while the second methodology benefits from geostatistical simulation of the EMI data pseudosection. This study demonstrates that DCT truncation based on geostatistical simulations facilitates a robust selection of the dominant DCT coefficients and their prior ranges, resulting in more accurate subsurface EC imaging from multi-configuration EMI data. Results based on geostatistical prior modeling present an excellent agreement between the EMI- and ERT-derived EC fields of the Chicken Creek catchment.

scholarly journals Strategic selection of an optimal sorbent mixture for in-situ remediation of heavy metal contaminated sediments: Framework and case study

2012 ◽  
Vol 105 ◽  
pp. 1-11 ◽  
Author(s):  
Y.W. Chiang ◽  
R.M. Santos ◽  
K. Ghyselbrecht ◽  
V. Cappuyns ◽  
J.A. Martens ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Contaminated Sediments ◽  
In Situ Remediation ◽  
Selection Of

scholarly journals Fuel economy assessment tool for auxiliary kite propulsion of merchant ship

2018 ◽  
pp. 5-7 ◽  
Author(s):  
Vincent Podeur ◽  
Damien Merdrignac ◽  
Morgan Behrel ◽  
Kostia Roncin ◽  
Caroline Fonti ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Assessment Tool ◽  
Round Trip ◽  
Merchant Ship ◽  
Added Resistance In Waves ◽  
The Mean ◽  
The Impact ◽  
Engine Power

A tool dedicated to assess fuel economy induced by kite propulsion has been developed. To produce reliable results, computations must be performed on a period over several years, for several routes and for several ships. In order to accurately represent the impact of meteorological trends variations on the exploitability of the kite towing concept, a time domain approach of the problem has been used. This tool is based on the weather database provided by the ECMWF. Two sailing strategies can be selected for assessing the performance of the kite system. For a given kite area, the simulation can be run either at constant speed or at constant engine power. A validation has been made, showing that predicted consumption is close from in-situ measurement. It shows an underestimation of 11.9% of the mean fuel consumption mainly due to auxiliary consumption and added resistance in waves that were not taken into account. To conclude, a case study is performed on a 2200 TEU container ship equipped with an 800m² kite on a transatlantic route between Halifax and Le Havre. Round trip simulations, performed over 5 years of navigation, show that the total economy predicted is of around 12% at a speed of 16 knots and around 6.5% at a speed of 19 knots.

On the Applicability of Analytical Supply Chain Disruption Models for Selecting the Optimum Contingency Strategies for Electronic Supply Chain Disruption Management: A Comparison With Simulation

2014 ◽  
Author(s):  
Hannah Allison ◽  
Peter Sandborn ◽  
Bo Eriksson
Keyword(s):  
Supply Chain ◽  
Mitigation Strategy ◽  
Mitigation Strategies ◽  
Analytical Models ◽  
Supply Chain Disruption ◽  
Simulation Based ◽  
Disruption Mitigation ◽  
The Impact ◽  
Selection Of

Due to the nature of the manufacturing and support activities associated with long life cycle products, the parts that products required need to be dependably and consistently available. However, the parts that comprise long lifetime products are susceptible to a variety of supply chain disruptions. In order to minimize the impact of these unavoidable disruptions to production, manufacturers can implement proactive mitigation strategies. Two mitigation strategies in particular have been proven to decrease the penalty costs associated with disruptions: second sourcing and buffering. Second sourcing involves selecting two distinct suppliers from which to purchase parts over the life of the part’s use within a product or organization. Second sourcing reduces the probability of part unavailability (and its associated penalties), but at the expense of qualification and support costs for multiple suppliers. An alternative disruption mitigation strategy is buffering (also referred to as hoarding). Buffering involves stocking enough parts in inventory to satisfy the forecasted part demand (for both manufacturing and maintenance requirements) for a fixed future time period so as to offset the impact of disruptions. Careful selection of the mitigation strategy (second sourcing, buffering, or a combination of the two) is key, as it can dramatically impact a part’s total cost of ownership. This paper studies the effectiveness of traditional analytical models compared to a simulation-based approach for the selection of an optimal disruption mitigation strategy. A verification case study was performed to check the accuracy and applicability of the simulation-based model. The case study results show that the simulation model is capable of replicating results from operations research models, and overcomes significant scenario restrictions that limit the usefulness of analytical models as decision-making tools. Four assumptions, in particular, severely limit the realism of most analytical models but do not constrain the simulation-based model. These limiting assumptions are: 1) no fixed costs associated with part orders, 2) infinite-horizon, 3) perfectly reliable backup supplier, and 4) disruptions lasting full ordering periods (as opposed to fractional periods).

scholarly journals Guests’ assessment of hotel facilities and services: Zadar case study

2020 ◽  
Vol 10 (3) ◽  
pp. 241-250
Author(s):  
Krzysztof Parzych ◽  
Jadranka Brkić-Vejmelka
Keyword(s):  
City Centre ◽  
Location Factors ◽  
Tourist Destination ◽  
Railway Station ◽  
Comfort Evaluation ◽  
Location Determinants ◽  
The Impact ◽  
The City ◽  
Selection Of

Abstract The availability of hotel facilities and services and their quality are one of the most important factor in selection of a tourist destination. The aim of the article was to analyse the impact of hotel location factors, prices of hotel services and detailed assessments of hotel services provided by the hotel on the overall rating of the hotel. As a case study, Zadar – a city located in the northern part of the Dalmatian coast of Croatia – was used to analyse the problem. The location determinants of hotels and their equipment were assessed in relation to the price of accommodation and tourists’ evaluation of the basic components of hotel services. The analysis used data obtained from the Booking.com website for accommodation prices, including selected days of the high and low season, data on the number of opinions about the object and the rating of the object by guests in terms of the overall opinion about the object, its location conditions, the standard of services rendered, cleanliness, comfort, evaluation of staff work, access to Wi-Fi network and assessment of services rendered in relation to the price of the service. The obtained results indicate hotel location, especially its distance from the city centre, railway station and airport and evaluation of chosen elements of customers’ hotel evaluation are most significant determinants of choosing accommodation for tourists.

scholarly journals ECOLOGICALLY BASED APPROACH TO COASTAL DEFENCE DESIGN AND PLANNING

2011 ◽  
Vol 1 (32) ◽  
pp. 50 ◽  
Author(s):  
Barbara Zanuttigh ◽  
Inigo Losada ◽  
Richard Thompson
Keyword(s):  
Standard Procedure ◽  
Combined Method ◽  
Ecological Data ◽  
Positive Effects ◽  
Environmental Friendly ◽  
As Species ◽  
Hydrodynamic Effects ◽  
The Impact ◽  
Selection Of

Sustainability of coastal areas requires the development of a standard procedure for the selection of equitable defence solutions and the design optimization of existing defences in order to minimize the impact on the environment and maximize positive effects such as species biodiversity and structure colonization. The aim of this paper is to propose a combined method, based on numerical simulations and on collection of ecological data in the field, to provide indications for an environmental friendly construction of breakwaters. This method is applied and tested against the case study of Elmer, UK, where information on existing species and their abundance related to hydrodynamic effects induced by the breakwaters

scholarly journals Assessing the efficiency of a “buried wall” barrier in the establishment of near-surface long-term storage and disposal facilities for RW

2021 ◽  
Vol 14 (1) ◽  
pp. 96-105
Author(s):  
V. V. Suskin ◽  
◽  
I. V. Kapyrin ◽  
F. V. Grigorev ◽  
◽  
...  
Keyword(s):  
Near Surface ◽  
Transfer Processes ◽  
Long Term Storage ◽  
Mass Transfer Processes ◽  
High Degree ◽  
The Impact ◽  
Term Storage

The article evaluates the impact of a “buried wall” barrier on the long-term safety during the long-term storage1 or in-situ disposal of nuclear legacy facilities, in particular, industrial reservoirs, as well as during the development of near-surface disposal facilities for radioactive waste (RWDF). For assessment purposes, filtration and mass transfer processes have been numerically modelled in the GeRa code based on a case study of a reference near-surface facility. The study explores in which way the available covering screen affects the dynamics of contaminant spread. It evaluates the sensitivity of the results to the dispersion parameter commonly characterized by a high degree of uncertainty.

scholarly journals On the Low Frequency Impact Noise Measurement in Residential Buildings

2021 ◽  
Vol 2069 (1) ◽  
pp. 012159
Author(s):  
D Urbán ◽  
P Zat’ko
Keyword(s):  
Acoustic Pressure ◽  
Residential Buildings ◽  
Low Frequency ◽  
Spatial Averaging ◽  
Impact Noise ◽  
Normative Requirements ◽  
Enclosed Space ◽  
The Cost ◽  
The Impact

Abstract We commonly encounter cases that, despite the fact that buildings meet normative requirements, people are disturbed by unwanted noise generated by walking and other sources of impact noise. It is not unusual that in practice the designer often moves on the edge of the required criteria in order to reduce the cost of constructions and its parts. In this article, we selected 4 blindly chosen cases of flats where complaints from residents about high levels of impact noise were recorded although the construction meets the requirements set out in the standard. Based on the obtained documentation of in-situ performed measurements by different consulting companies, BEM and FEM models were created, and the distribution of acoustic pressure in an enclosed space and compared different methods of spatial averaging of the resulting acoustic pressure were simulated. The aim of this analysis is to point some of the reasons for possible user complaints about the impact noise despite normative requirements. The usual problems are benevolent national requirements and the issue of measuring noise in the low frequency range and underestimating its significance. The article also discusses the currently set requirements for the evaluation of floor structures in selected countries.

scholarly journals The Issue of Operating Security Systems in Terms of the Impact of Electromagnetic Interference Generated Unintentionally

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8591
Author(s):  
Krzysztof Jakubowski ◽  
Jacek Paś ◽  
Adam Rosiński
Keyword(s):  
Electromagnetic Interference ◽  
Process Model ◽  
Low Frequency ◽  
Security Systems ◽  
Operating Process ◽  
Impact Coefficient ◽  
Transport Telematics ◽  
The Impact ◽  
Technical And Organizational Measures ◽  
Selection Of

This article discusses issues regarding electromagnetic interference generated unintentionally by transport telematics systems and electronic security systems (ESS) located within a railway area. These systems should operate correctly, since they ensure the safety of both vehicles and passengers. The electronic devices they use are exposed to electromagnetic interference that may lead to incorrect ESS functioning. In order to determine the impact of electromagnetic interference on ESS, the authors measured unintentional low-frequency electromagnetic field generated by MV—15 and 30 kV—power lines. This enabled determining the areas with maximum values of electromagnetic interference. The next stage of the research was to develop an ESS operating process model that takes into account the impact of unintentionally generated electromagnetic interference on the operating process. Introducing the electromagnetic interference impact coefficient enables a rational selection of solutions aimed at protecting against electromagnetic interference through the application of technical and organizational measures.

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