Time filter

Source Type

Madrid, Spain

Fernandez J.A.,Technical University of Madrid | Martinez C.,Technical University of Madrid | Magdaleno F.,Ministry of Public Works
Environmental Science and Policy | Year: 2012

In Europe, the Water Framework Directive (2000/60/EC) demands the achievement of a good ecological status for water bodies by 2015. However, it also defines exceptions to these objectives, such as a good ecological potential instead of a good ecological status or a more distant temporal horizon than 2015. Those exceptions may only be applied to heavily modified water bodies (HMWBs). This paper presents a method, P-IAHRIS, incorporated into the free software IAHRIS v2.2, that offers objective criteria for the preliminary designation of HMWBs downstream from irrigation dams, flood protection dams or drinking water supply dams. The procedure incorporates two indicators: (i) the P10%-90% indicator, which analyses the alterations in the flow regime associated with the range of natural variability defined by the 10th and 90th percentiles of the annual and monthly discharges; and (ii) the IHA-HMWB indicator, which assesses the changes in the magnitude, seasonality, variability and duration of natural flows. P-IAHRIS was applied to 103 water bodies in Spain. The functionality and versatility of the method have been proven and allow the fast and objective preliminary designation of HMWBs, both in the Mediterranean and Atlantic environments. © 2011 Elsevier Ltd. Source

Adekristi A.,Ministry of Public Works | Eatherton M.R.,Virginia Polytechnic Institute and State University
Journal of Earthquake Engineering | Year: 2015

Time-domain spectral matching of an earthquake ground motion consists of iteratively adding sets of wavelets to an acceleration history until the resulting response spectrum sufficiently matches a target spectrum. The spectral matching procedure is at its core a nonlinear problem because the addition of a wavelet often causes shifting in the time of peak response or creation of a larger second peak at a different time. A modification to existing time-domain spectral matching algorithms is proposed using Broyden updating for solving the set of nonlinear equations. Three wavelet bases are evaluated and the corrected tapered cosine wavelet is selected. The proposed algorithm is then tested and compared with other methods that are commonly used for spectral matching. The results show that the proposed algorithm is able to match the target spectrum while reasonably preserving the spectral nonstationarity, energy development, and the frequency content of the original time histories. © 2015, Taylor & Francis. All rights reserved. Source

Alaejos P.,CEDEX | Alaejos P.,Polytechnic University of Mozambique | Lanza V.,CEDEX | Bermudez M.A.,Ministry of Public Works | Velasco A.,CEDEX
Cement and Concrete Research | Year: 2014

The accelerated mortar bar test (AMBT) is one of the most common tests to detect reactive aggregates although it has some limitations: there is no agreement on the limit of expansion, fails appear when testing slowly reactive aggregates and a laborious work is needed to find the pessimum content. An experimental programme on the AMBT has been carried out to overcome these limitations. Rapid and slowly reactive aggregates extracted from real Spanish structures affected by alkali silica reaction have been used. As a result, the test detected correctly all the reactive aggregates, but with the following requirements: a limit of 0.10% at 14 days for rapid reactive aggregates and 0.20% at 90 days for slowly reactive aggregates. Also the pessimum content has been found between 5 and 15 vol% of equivalent reactive quartz, giving a peak expansion of 0.42% (14 days). The expansion after this peak decreased but it was always over 0.10%. © 2014 Published by Elsevier Ltd. Source

Zaied A.N.H.,Zagazig University | Al Othman W.,Ministry of Public Works
Expert Systems with Applications | Year: 2011

In a conventional traffic signals controller, the lights change at constant cycle time. In many cities, automatic traffic signals are often based on a constant green-to-red cycle. The time period for green light (or red light) to be on is determined based on a stochastic model. The traditional vehicle-actuated control of isolated intersections attempts continuously to adjust green times. The decision to change green light duration involves fuzzy factors that cannot be precisely determined. The main objective of this paper is to develop a fuzzy logic traffic system that considers the two two-way intersections and is able to adjust changes in time intervals of a traffic signal based on traffic situation level. The proposed system has been applied and tested using real data collected from signalized intersection in Hawalli governorate in the State of Kuwait. Twenty-seven iterations have been done; the results show that the proposed fuzzy logic traffic system provides better performance in terms of total waiting time, total moving time, and vehicle queue. Finally, it can be observed from the results that the proposed system can be used to accelerate the cycle time and to give other phases the chance to gain more benefit from the green time lost. © 2011 Published by Elsevier Ltd. Source

Dewi R.C.,Ministry of Public Works
34th Asian Conference on Remote Sensing 2013, ACRS 2013 | Year: 2013

Animation is one of potential methods to visualize change of phenomena in time series. But users might be overwhelmed by the number of changes displayed in an animation of long time series. Users then need to reduce the amount of information displayed. Since different phenomena may change in different time intervals, modifying temporal unit tools are developed as supporting tools for improving animation environment. This paper presents the development of the tools in ILWIS, an open source GIS software package. As a case study, NDVI data derived from satellite images SPOT VEGETATION are used to implement the functionalities of the tools. The tools propose advanced functionality for animating and interacting with time, filtering data by their attribute, and aggregating data by time unit. Equipped with time series graph and proposed time selection tools, animation allows users to answer visual exploration questions related to attribute (what), location (where) and time (when, how long, how often). Source

Discover hidden collaborations