scholarly journals High-Definition Field Texture Measurements for Predicting Pavement Friction

2019 ◽  
Vol 2673 (1) ◽  
pp. 246-260 ◽  
Author(s):  
Natalia Zuniga-Garcia ◽  
Jorge A. Prozzi
Keyword(s):  
Panel Data Analysis ◽  
Laser Scanner ◽  
Field Measurements ◽  
Surface Friction ◽  
Alternative Methods ◽  
High Definition ◽  
Pavement Surface ◽  
Pendulum Test ◽  
Profile Depth ◽  
Friction Models

Monitoring and managing skid resistance properties are crucial activities to reduce the number of highway accidents and fatalities. However, current methodologies to measure pavement surface friction present several disadvantages that make them impractical. Thus, it is necessary to evaluate alternative methods to estimate friction. The principal objective of this study was to develop friction models based on pavement texture. We implemented a Line Laser Scanner (LLS) to obtain an improved characterization of the pavement texture which includes macrotexture and incorporates microtexture description using eight different parameters. Field measurements of friction and texture were collected around Texas using the British Pendulum Test (BPT), the Dynamic Friction Test (DFT), the micro-GripTester, and the LLS. The experimental results showed that there is not a unique relationship between texture and friction; though strong and statistically significant, the relationship is different for each type of pavement surface. Thus, regression analysis pooling all data cannot be utilized to quantify this relationship. For this reason, we applied a panel data analysis approach that allows the incorporation of the type of surface and provides a more robust analysis. The results indicate that the prediction of friction is significantly improved when incorporating information from both macrotexture and microtexture into the prediction model. Therefore, a measure of microtexture should be included into friction models based on texture. In addition, the study of different texture parameters suggests that the mean profile depth (MPD) is the most significant parameter for macrotexture and for microtexture to explain the distinct friction measures.

Monitoring Pavement Surface Macrotexture and Friction

2015 ◽  
Vol 2525 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Nima Kargah-Ostadi ◽  
Andrew Howard
Keyword(s):  
Surface Friction ◽  
Vehicle Speed ◽  
The Road ◽  
Pavement Surface ◽  
Friction Testing ◽  
Profile Depth ◽  
Friction Measurements ◽  
On The Road ◽  
The Relationship

The amount of available friction and texture depth are primary concerns in the evaluation of pavement surface safety characteristics. The two components of microtexture and macrotexture provide pavement surface friction. Macrotexture properties are collected with laser-based devices at highway speeds, but a proper evaluation of microtexture is available only with stationary devices or laboratory experimental methods. The industry is trying to develop practical methods for monitoring microtexture at the network level. Pertinent quantification for both friction components is valued because the common locked-wheel testing of skid resistance depends on surface temperature, presence of dirt and oil on the road surface, and vehicle speed. This case study examined the relationship between laser-based mean profile depth (MPD) and the friction number (FN) collected with a locked-wheel skid trailer on Louisiana highways. The analysis showed that quantified microtexture data were required in conjunction with the macrotexture to establish a significant correlation with friction measurements. However, the correlation between MPD and FN appeared to be significantly stronger at higher speeds of friction testing. Lower and higher threshold values were determined from the first and third quartiles of MPD and FN data. At speeds of about 50 mph, 71% of the pavement sections with MPD of less than the lower texture threshold also had FN values of less than the lower friction threshold. This lower MPD threshold of 0.036 in. can be implemented in network-level monitoring operations to determine areas of concern that require friction testing.

scholarly journals FIELD MEASUREMENTS ON RUNWAY FRICTION DECAY RELATED TO RUBBER DEPOSITS

Transport ◽  
2016 ◽  
Vol 31 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Mario De Luca ◽  
Francesco Abbondati ◽  
Thomas J. Yager ◽  
Gianluca Dell’Acqua
Keyword(s):  
Functional Capacity ◽  
Field Measurements ◽  
Surface Characteristics ◽  
Air Traffic ◽  
Pavement Surface ◽  
Vulcanized Rubber ◽  
Before And After

Surfaces of airport pavements are subject to contamination that can be very dangerous for the movement of aircraft particularly on the runway. A recurrent problem is represented by the deposits of vulcanized rubber of aircraft tires in the touchdown area during landings and lesser during take-offs. This causes a loss of grip that compromises the safety of aircraft movements in take-off and landing operations. This study deals with the surface characteristics decay phenomenon related to contamination from rubber deposits. The experiment was conducted by correlating the pavement surface characteristics, as detected by Grip Tester, to air traffic before and after de-rubberizing operation and two models were constructed for the assessment of functional capacity of the runway before and after the operations de-rubberizing.

scholarly journals Cultural Relativity, Human Rights and the International Regulation of Broadcasting

2021 ◽  
Author(s):  
◽  
Andrew Robert Jack
Keyword(s):  
Human Rights ◽  
International Law ◽  
Freedom Of Expression ◽  
Cultural Development ◽  
Alternative Methods ◽  
High Definition ◽  
International Regulation ◽  
Cultural Relativity ◽  
International Broadcasting ◽  
The Impact

<p>When a broadcaster broadcasts directly to people living in another state disputes can arise. The audience may find the programmes offensive. The programmes may foment disorder and rebellion and corrupt the values and traditions of the inhabitants of the receiving state or even threaten their very survival. The problem is not new. It has been a source of international tension since the inception of broadcast technology. The problem has however become more pointed as that technology has become ever more sophisticated. The power of radio is aptly illustrated by recalling the panic caused in 1938 by Orson Welles' famous hoax broadcast announcing the invasion of Earth by Martians. More recently commentators such as James Miles, BBC correspondent in Peking at the time, have suggested that the rebellion in China before and after the massacre at Tianamen Square was fomented, prolonged and to a degree coordinated by programmes broadcast on overseas radio stations such as Voice of America and the BBC. Television has a much greater graphic capacity than radio and is also vulnerable to abusive techniques such as subliminal suggestion and advertising. The impact of television is set for another great leap ahead as the development of High Definition Television technology proceeds apace. The development of communications satellites has greatly increased the range and quality of broadcasts. There have been a number of attempts to address this problem but none have met with much success. The international community has polarised into two camps, one taking a position based on a very strict view of the right to freedom of expression, and the other insisting that that right yield to a degree at least to accommodate peoples' rights to determine their own economic, social and cultural development. This paper offers a solution to this impasse. It offers guidelines to help resolve international broadcasting disputes. The guidelines are based on the international human right to freedom of expression as viewed particularly by the two bodies responsible for drafting that right's most famous exposition in the Universal Declaration of Human Rights and in the host of other international and constitutional instruments which it inspired. It is argued that cultural relativity in the human rights context is consistent with the sources of international law specified in article 38 of the statue of the International Court of Justice, and that by incorporating a degree of cultural relativity the guidelines advocated herein are similarly consistent with current international law. It is also shown that the view of human rights the guidelines evince is consistent with a version of constructivist human rights theory which accords with observable practice and which enjoys widespread academic support. Some alternative methods for addressing the problem arising from international broadcasting are examined and their shortcomings identified. This leads to the conclusion that the method proposed in this paper for regulating international broadcasting, notwithstanding that it is most surely within the realm of de lege ferenda, is both consistent with current international law and jurisprudentially defensible, and therefore better than the alternatives.</p>

scholarly journals Flood risk assessment and cultural heritage impact in the Instituto Superior de Arte (ISA) in Habana.

2020 ◽  
Author(s):  
Daniele Fabrizio Bignami ◽  
Leonardo Stucchi ◽  
Daniele Bocchiola ◽  
Christian Zecchin ◽  
Davide Del Curto ◽  
...  
Keyword(s):  
Flood Risk ◽  
Laser Scanner ◽  
Drainage System ◽  
Digital Terrain Model ◽  
Field Measurements ◽  
Point Of View ◽  
Discharge Data ◽  
Terrain Model ◽  
Critical Discharge ◽  
The Status

&lt;p&gt;Keeping ISA Modern is a project of Fondazione Politecnico di Milano and other partners aimed at planning the conservation of some of the buildings (Schools) of the University of Arts (ISA) of Cuba, built over a former country club, designed by eminent architects of the time (Vittorio Garatti, Roberto Gottardi and Ricardo Porro), and bestowed with the status of UNESCO World Heritage in 2003.&lt;/p&gt;&lt;p&gt;Most of the Schools are currently unusable, also due to damages caused by frequent floods from the surrounding Rio Quib&amp;#249; river, and they need urgent restoration if they are to be used. Personnel of Politecnico di Milano carried out a field survey on the Rio Quib&amp;#249; during 2019, and also based upon information from the Cuban National Institute of Hydraulic Resources (INRH) they studied established flood risk for ISA.&lt;/p&gt;&lt;p&gt;Here, we built a high-resolution digital terrain model (DTM) of the park where Schools are located, using laser scanner data, and previously georeferenced points. Using field measurements taken in June 2019 we were able to assess geometry (included bridges), slope and roughness coefficients of the main channel of the Quib&amp;#249; river, influence of the sea level. Then using as input critical discharge data provided by INRH we evaluated flood area and flood volume for 4 representative return periods (5, 20, 50, 100 years).&lt;/p&gt;&lt;p&gt;The most impacted building is the School of Ballet, located within a narrow meander of Rio Quib&amp;#249;, immediately upstream of a narrow bridge, clogging largely during floods, only 1 km far from the sea, and with drainage system unable to discharge storm water.&lt;/p&gt;&lt;p&gt;Given the high required cost, a partially collapsed wall originally partially protecting the School of Ballet was not rebuilt, and we are now exploring flood mitigation strategy which are cheaper, and feasible from the point of view of compatibility with the historical and architectural value of the building.&lt;/p&gt;

scholarly journals BARRIER AND GUARDRAIL EXTRACTION AND CLASSIFICATION FROM POINT CLOUDS

2020 ◽  
Vol XLIII-B5-2020 ◽  
pp. 157-162
Author(s):  
M. Vidal ◽  
L. Díaz-Vilariño ◽  
P. Arias ◽  
J. Balado
Keyword(s):  
Traffic Safety ◽  
Autonomous Vehicles ◽  
Global Economy ◽  
Laser Scanner ◽  
Point Clouds ◽  
High Definition ◽  
Simple Method ◽  
Concrete Barriers ◽  
Parameter Dependent

Abstract. In the recent years, the modelling of infrastructures has been receiving increasingly attention due to the importance of transport infrastructures for global economy, traffic safety and for the generation of high definition maps, essential to autonomous vehicles. This paper presents a simple method for the segmentation and classification of concrete barriers and guardrails in road surroundings. First steps of the method are aimed to delimit the region of the point cloud outside the driving lanes in which barriers and guardrails are installed. The purpose is to significantly reduce the size of point clouds in order to improve further processing. Then, barrier segmentation and classification are designed as parameter-dependent processes because the geometric features of roads and barriers and guardrails are mostly regulated by norms and standards. Results show a good performance in terms of classification in comparison of other state of the art methods. Better results were obtained for guardrails than for concrete barriers. The method has been tested in a set of point clouds acquired with a Mobile Laser Scanner from conventional roads and highways.

scholarly journals Modelling Site Index in Forest Stands Using Airborne Hyperspectral Imagery and Bi-Temporal Laser Scanner Data

2019 ◽  
Vol 11 (9) ◽  
pp. 1020 ◽  
Author(s):  
Bollandsås ◽  
Ørka ◽  
Dalponte ◽  
Gobakken ◽  
Næsset
Keyword(s):  
Atmospheric Correction ◽  
Laser Scanner ◽  
Field Measurements ◽  
Site Index ◽  
Hyperspectral Data ◽  
Average Height ◽  
Single Time ◽  
Development Site ◽  
Corrected Data ◽  
Selection Of

In forest management, site index information is essential for planning silvicultural operations and forecasting forest development. Site index is most commonly expressed as the average height of the dominant trees at a certain index age, and can be determined either by photo interpretation, field measurements, or projection of age combined with height estimates from remote sensing. However, recently it has been shown that site index can be accurately predicted from bi-temporal airborne laser scanner (ALS) data. Furthermore, single-time hyperspectral data have also been shown to be correlated to site index. The aim of the current study was to compare the accuracy of modelling site index using (1) data from bi-temporal ALS; (2) single-time hyperspectral data with different types of preprocessing; and (3) combined bi-temporal ALS and single-time hyperspectral data. The period between the ALS acquisitions was 11 years. The preprocessing of the hyperspectral data included an atmospheric correction and/or a normalization of the reflectance. Furthermore, a selection of pixels was carried out based on NDVI and compared to using all pixels. The results showed that bi-temporal ALS data explained about 70% (R2) of the variation in the site index, and the RMSE values from a cross-validation were 3.0 m and 2.2 m for spruce- and pine-dominated plots, respectively. Corresponding values for the different single-time hyperspectral datasets were 54%, 3.9 m, and 2.5 m. With bi-temporal ALS data and hyperspectral data used in combination, the results indicated that the contribution from the hyperspectral data was marginal compared to just using bi-temporal ALS. We also found that models constructed with normalized hyperspectral data produced lower RMSE values compared to those constructed with atmospherically corrected data, and that a selection of pixels based on NDVI did not improve the results compared to using all pixels.

scholarly journals A Multi-Method Approach for Quantification of In- and Exfiltration Rates from the Subterranean Estuary of a High Energy Beach

2020 ◽  
Vol 8 ◽  
Author(s):  
Nele Grünenbaum ◽  
Janis Ahrens ◽  
Melanie Beck ◽  
Benjamin Silas Gilfedder ◽  
Janek Greskowiak ◽  
...  
Keyword(s):  
Exchange Rates ◽  
Time Scales ◽  
Laser Scanner ◽  
Field Measurements ◽  
High Water ◽  
High Energy ◽  
Water Infiltration ◽  
Spatial And Temporal Variability ◽  
Detailed Knowledge ◽  
Water Volumes

Accurate SGD (submarine groundwater discharge) mass export calculations require detailed knowledge of the spatial and temporal variability in SGD rates. In coastal aquifers, SGD includes a terrestrial freshwater component as well as a saline component originating from circulating seawater. Representative field measurements of SGD rates are difficult to conduct, because SGD is often patchy, diffuse, and temporally variable, especially under tidal influence and high wave activity. In this study, a combination of lysimeters, seepage meters, temperature sensors, pore water radon, and numerical modeling was used to estimate the volumes of infiltrating seawater and exfiltrating groundwater in the intertidal zone of a mesotidal, high energy beach on Spiekeroog Island, northern Germany. Additionally, a 3D-laser scanner was used over short (days) and medium time scales (months) to determine changes in beach topography. The results showed net water infiltration above mean sea level (MSL) and net exfiltration below MSL. Water exchange rates fluctuated between 0.001 and 0.61 m day−1, showing similar ranges within the multiple method approaches. The beach topography was subject to strong fluctuation caused by waves, currents, wind driven erosion and sedimentation, even over short time scales. A comparison of extrapolated in- and exfiltrating water volumes along a beach transect from the mean high water to mean low water line at different times highlights the variability of total in or outflow. The results show that exchange rates depend on beach topography, which in turn changes significantly over time.

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