Maria L. Simões

Application of Data Mining Techniques

In this chapter, the data mining techniques described in chapter 3 are applied to the case study described in chapter 4. The overcome of the difficulties associated with the analysis process of the data using appropriate techniques is demonstrated.

Modeling and Simulation of Traffic Movements at Semiactuated Signalized Intersections

This work presents a microscopic stochastic simulation model that emulates the traffic movements at signalized intersections with semiactuated signal operation. This model uses the Awesim simulation language to implement and facilitate the evaluation of numerous operating scenarios associated with vehicle-actuated control strategies at isolated signalized intersections. A validation procedure was carried out, field data were collected, and delays and green times observed in the field were compared with those estimated by the simulation program. The adequacy of this model to represent real-world systems is shown. The structure of the model and the steps that were followed for its implementation are described. The relationship between simulated delays and the delays obtained from applying the Highway Capacity Manual model is analyzed. The impact of the maximum green time and the unit extension of green time assigned by the actuated system to each phase is also assessed. The model outputs include measures of...

The fully actuated traffic control problem solved by global optimization and complementarity

Global optimization and complementarity are used to determine the signal timing for fully actuated traffic control, regarding effective green and red times on each cycle. The average values of these parameters can be used to estimate the control delay of vehicles. In this article, a two-phase queuing system for a signalized intersection is outlined, based on the principle of minimization of the total waiting time for the vehicles. The underlying model results in a linear program with linear complementarity constraints, solved by a sequential complementarity algorithm. Departure rates of vehicles during green and yellow periods were treated as deterministic, while arrival rates of vehicles were assumed to follow a Poisson distribution. Several traffic scenarios were created and solved. The numerical results reveal that it is possible to use global optimization and complementarity over a reasonable number of cycles and determine with efficiency effective green and red times for a signalized intersection.

Queues with Server Vacations as a Model for Pretimed Signalized Urban Traffic

A queuing system resulting from a signalized intersection regulated by pretimed control in a network of urban traffic is considered. Modeling the queue length and the delay of vehicles is crucial to evaluate the performance of intersections equipped with traffic signals. Air quality and rational use of energy also depend on an efficient management of the intersections. These traffic systems have the specificity that the server (green signal) is deactivated (red signal) during a fixed period of time. In the present work, an M/D/1 queue with a server that occasionally takes vacations is analyzed. The mean delays of vehicles and the mean queue length are computed and compared with those obtained by using a detailed simulation model in a case study. We find that, in general, the mean delays of vehicles given by the proposed queuing model provide a good approximation, but the model can provide slightly smaller values than those obtained in the simulation model for large traffic flows. This result is of interes...

Probabilistic Risk Assessment Methodology of Exterior Surfaces Defacement Caused by Algae Growth

AbstractThis paper presents the development of a risk assessment methodology applicable to the analysis of exterior surfaces defacement from algae growth. The specific case of external thermal insulation composite systems (ETICS) is frequently associated with a higher perceived risk if compared with other facade solutions. The design of the proposed methodology includes: the scope of the risk analysis definition, the determination of the parameters involved using a qualitative analysis of the problem, the collection of relevant data, and a quantitative probabilistic risk analysis based in Monte Carlo simulations. The detailed implementation of the methodology involved the preparation of a meta-model, response surface methodology, that was developed and compared with a hygrothermal simulation tool. The meta-model allowed a faster application of the Monte Carlo method, providing results of the methodology application to the use of ETICS in selected locations and a sensitivity analysis of the stochastic para...

Application of a Particular Class of Markov Chains in the Assessment of Semi-actuated Signalized Intersections

We investigate a queuing model for a signalized intersection regulated by semi-actuated control in a urban traffic network. Modelling the queue length and the delay of vehicles for this type of traffic, characterized by variable durations of the green signal, is crucial to evaluate the performance of traffic intersections. Additionally, determining the size of the extensions of the green signal is also relevant. The traffic systems addressed in the paper have the particularity that the server remains active (green signal) for a period of time that depends on the number of vehicles waiting at the intersection. This gives rise to an M/D/1 queuing system with a server that occasionally takes vacations (red signal), for which we compute the long-run mean delay of vehicles, mean queue length and mean duration of the green signal. We consider a case study and compare the results obtained from the proposed queueing model with those obtained by using a microsimulation model. The formulas derived for the performance measures are of interest for traffic engineers, since the existing alternative formulas are subject to strong criticism.

Data Mining Techniques

This chapter presents available data mining techniques that can be of interest for application in indoor environment analysis. Descriptive statistics tools are presented with the focus on probability distribution and correlation analysis. Multivariate data techniques are also addressed, with a special focus on principal components determination and cluster analysis.

Indoor Hygrothermal Conditions

The evaluation of indoor hygrothermal conditions is described, supported by a literature review. Involved parameters and standardized methodologies are summarized. The procedures for evaluation of human comfort are also briefly described.

Applicability of the Pull-Off Test: Teachings from a Large Sample of In Situ Tests

The Pull-off test is a very popular way of evaluating the adhesion strength of renderings or ceramic tiles. Several standards frame the application of this test and interpretation of its results. In our laboratory, the in situ pull-off test is frequently applied to support the diagnosis of causes for building anomalies. The statistical meaning of the results, however, is clearly different from the one found in laboratory tests and hence reliability issues arise. In this work, 55 case studies based on in situ tests are analysed. The sample was retrieved from 15 test reports conducted by LFC-FEUP. In each of these reports different situations are included in terms of wall components, expected hygrothermal loads and aging history. This large number of tests supports a discussion on the applicability of the pull-off test regarding its reliability as a tool for two different subjects: decisions on repair strategies and building forensics. Typical variability found in field tests is described and analysed. The reliability of the test is analysed in detail with the help of one specific case where 40 individual pull-offs were conducted in the same building.