Designing a Structural Health Monitoring System Accounting for Temperature Compensation

Structural health monitoring is effective if it allows us to identify the condition state of a structure with an appropriate level of confidence. The estimation of the uncertainty of the condition state is relatively straightforward a posteriori, i.e., when monitoring data are available. However, monitoring observations are not available when designing a monitoring system; therefore, the expected uncertainty must be estimated beforehand. This paper proposes a framework to evaluate the effectiveness of a monitoring system accounting for temperature compensation. This method is applied to the design process of a structural health monitoring system for civil infrastructure. In particular, the focus is on the condition-state parameters representing the structural long-term response trend, e.g., due to creep and shrinkage effects, and the tension losses in prestressed concrete bridges. The result is a simple-to-use equation that estimates the expected uncertainty of a long-term response trend of temperature-compensated response measurements in the design phase. The equation shows that the condition-state uncertainty is affected by the measurement and model uncertainties, the start date and duration of the monitoring activity, and the sampling frequency. We validated our approach on a real-life case study: the Colle Isarco viaduct. We verified whether the pre-posterior estimation of expected uncertainty, performed with the experimented approach, is consistent with the real uncertainty estimated a posteriori based on the monitoring data.

On necessity for analytical solution of the Bloch equations for nuclear magnetic resonance signals at condition express control of liquid medium

The necessity of using express analysis methods to control medium condition is substantiated. It has been shown that the method of express control based on the phenomenon of nuclear magnetic resonance is one of the most preferable. It was found that to increase the information about the medium condition state obtained from the recorded NMR signal, it is necessary to use a mathematical model (based on analytical solutions of the Bloch equations). Two approaches are considered that are used to describe the NMR signal in a liquid medium. It is determined that in the classical approach in the system of Bloch equations it is possible to take into account the peculiarities of using radiotechnical methods of signal registration. The direction of the analytical solution of the Bloch equation is proposed. The experimental data are compared with the numerical solution.

Forecasting Federal Transportation Performance Management Bridge Condition Measures for Bridge Management

Many common processes of bridge management can benefit from network-level analysis of long-term costs and condition, on a time frame of about 10 years. Such processes include development and implementation of Transportation Asset Management Plans, long-range needs analysis, capital budgeting and programming, and policy analysis. The ability to forecast federal Transportation Performance Management (TPM) condition measures would provide managers with a way of evaluating the possible outcomes of funding, programming, and policy decisions. A model for this purpose has been developed as a part of StruPlan, an open-source spreadsheet for long-range renewal planning for transportation structures. Element condition state data are found to be highly exponential in distribution, while the federal measures “Percent Good” and “Percent Poor” are categorical when applied to specific bridges. Element data, providing more detail about the type, severity, and extent of defects, are valuable for deterioration modeling, while the TPM measures are simpler for reporting to stakeholders. A set of models was developed to bridge the gap between these measures. Thus far, the models have been calibrated and pilot tested using Idaho, South Dakota, and Kentucky data. The model is a novel approach that has not been attempted elsewhere, that may simplify important parts of bridge management and provide some valuable new ideas for researchers and developers.

What state of the world are we in? Targeted monitoring to detect transitions in vegetation restoration projects.

Monitoring vegetation restoration is challenging because ‘best practice’ monitoring is costly, requires long-term funding, and involves monitoring multiple vegetation variables which are often not linked back to learning about progress toward objectives. There is a clear need for the development of targeted monitoring programs that focus on a reduced set of variables that are tied to specific restoration objectives. In this paper, we present a method to progress the development of a targeted monitoring program, using a pre-existing state-and-transition model. We i) use field data to validate an expert-derived classification of woodland condition states; ii) use this data to identify which variable(s) help differentiate woodland condition states; and iii) identify the target threshold (for the variable) that signifies the desired transition has been achieved. The measured vegetation variables from each site in this study were good predictors of the different states of vegetation condition. We show that by measuring only a few of these variables, it is possible to assign the vegetation condition state for a collection of sites, and monitor if and when a transition to another state has occurred. Out of nine vegetation variables considered, the density of immature trees and percentage of exotic understorey vegetation cover were the variables most frequently specified as effective to define a threshold or transition. We synthesise findings by presenting a decision tree that provides practical guidance for the development of targeted monitoring strategies for woodland vegetation.

A Randomised Comparison of Values and Goals, Versus Goals Only and Control, for High Nonclinical Paranoia

Background Paranoia is common in the general population. Focusing on values and enhancing value-based acts may attenuate it. This study compared three brief (30-min, self-directed) online conditions: focusing on values and value-based goal setting (n = 30), goal setting only (n = 32) and non-values/goals control (n = 32) in a high paranoia sample. Methods Participants were randomly assigned to condition. State paranoia (primary outcome) and positive and negative self-views following a difficult interpersonal experience (secondary outcome) were assessed at baseline and two-weeks. Results Intention-to-treat: state paranoia was significantly lower following the values condition as compared to non-values/goals control (ηp2 = .148) and goals only (ηp2 = .072). Only the former comparison was significant. Per-protocol: groups did not significantly differ (p = .077). Within-group effect sizes: values and value-based goal setting (intention-to-treat d = .82, per-protocol d = .78), goals only (intention-to-treat d = .41, per-protocol d = .42) non-values/goals control (intention-to-treat d = .25, per-protocol d = .24). Positive self-views increased in all conditions. The increase was largest for the values condition, but not significantly so. Limitations Reliance on self-report, brief follow-up, predominantly White female sample. Conclusions The values condition was most effective at reducing non-clinical paranoia. The values condition appeared to increase positive self-views more so than comparison groups, but the sample was small and the difference was non-significant.

Comprehensive Feature Analysis for Sewer Deterioration Modeling

Timely maintenance of sewers is essential to preventing reduced functionality and breakdown of the systems. Due to the high costs associated with inspecting a sewer system, substantial research has focused on sewer deterioration modeling and identification of the most useful features. However, there is a lack of consensus in the findings. This study investigates how the feature importance depends on the definition of bad pipes and how the feature importance changes between utilities with similar data bases. A dataset containing 318,457 pipes from 35 utilities with a condition state (CS) ranging from one to four was used. The dataset was cleaned, and a backward step analysis (BSA) was applied to two ways of binarizing the CS. Additionally, a BSA was applied for each utility with ≥100 pipes in CS four. The results showed that a selective definition of bad pipes reduced the performance and changed the order of which features contributed the most. In each case, either year of construction, age, groundwater, year of rehabilitation, or dimension was the most important feature. On average 6.5 features contributed to the utility-specific models. The feature analysis was sensitive to the inspection strategy, the size of the dataset, and interdependency between the features.

Performance assessment on degrading concrete structures including considerations on the time variant alteration

<p>The infrastructure of ASFiNAG is mainly built from reinforced and prestressed concrete, which despite all regular maintenance measures, is subject to ageing and degradation. The major degradation process is chloride attack, followed by carbonation, which both lead to corrosion of the reinforcing steel. In this paper chlorides in the concrete are analysed with a new method, which represents a major improvement over previous assessment. The paper also introduces a new concept for the durability assessment by using objective indicators, like chloride content, electrical resistivity, and corrosion potential. For objectivity and a reliable determination of the condition state, an overall performance index derived from the condition indices using an analytic hierarchy process (AHP) is adopted. The model is applied to excellent and dense data from a monitoring system and investigations taken from reinforced concrete components beside the motorway.</p>

Tramps’ Tales: Discovering the Life-Stories of Late Victorian and Edwardian Vagrants*

This article addresses a question that challenged British policy-makers at the turn of the twentieth century: who were the tramps? Using genealogical methods, the article shows the extent, and detail, with which it is now possible to reconstruct a vagrant’s life. Understanding these life-stories, of people trapped in a system of state control and surveillance, opens up the potential to unravel the strategies and inner logics that they were applying in order to survive. For the most part, these individuals were punished and criminalised by the New Poor Law and 1824 Vagrancy Act on the basis of their personal condition, state of being and socio-economic status. The article will illustrate how it is now possible to pinpoint a tramp’s movements around the country, and understand the individuality of these routes. And finally, in addressing the debates about why people found themselves in this predicament, the article argues that individual fragilities contributed significantly to the circumstances they experienced.

Building relational capacities from institutional arrangements: lessons based on the construction of Salvador's subway system

This article aims to study the construction process of the subway system in the Brazilian cities of Salvador and Lauro de Freitas, investigating the constraints of state agencies to build this subway infrastructure. By examining the structures created to produce this urban infrastructure policy, this paper tries to explain how institutional arrangements of public policies condition state agency, in other words, how they enhance or undermine the formation of policy capacities to deliver subway infrastructure. The qualitative analysis of the data suggests that the design of institutional arrangements and their change influence the availability and mobilization of actors, resources, competences and policy instruments towards the promotion of efficacy and legitimacy in this policy.

Urban streams in Latin America: Current conditions and research needs

Introduction: Latin America is a highly urbanized region, with most of its population living in cities and urban centers. While information about urban streams in Latin America is rather limited, streams are expected to experience similar environmental impacts and conservation issues as urban streams in parts of the globe, including habitat loss, channelization, sewage discharge, trash, and loss of riparian habitats. Objective: We surveyed a network of researchers from approximately 80% of the countries in Latin America to obtain information on the condition, state of knowledge, and threats to urban streams in the region. Methods: Most participants were reached via the Macrolatinos@ network (www.macrolatinos.net). Results: We obtained 104 responses from researchers in 18 of the 23 Latin American countries. Most urban streams are impacted or degraded, and inputs of contaminants and wastewater discharges were considered major drivers of stream degradation. Most respondents indicated that stream channelization is common, with some streams completely channelized or buried. Sewage and rainfall runoff management were identified as a major factor degrading streams, with most respondents suggesting that streams are a primary destination for wastewater discharge, much of which is untreated. Major limitations to urban stream conservation in Latin America are the result of limited ecological knowledge, lack of citizen interest or political will to protect them. There are isolated efforts to restore urban streams and riparian zones, but these are initial steps that need further development. Conclusions: Our research network of Latin American scientists proved to be a valuable tool to assess a large number of urban rivers in a relatively understudied region. Urban streams in Latin America face a diversity of stressors and management challenges, and we propose three areas that would benefit from further research to improve our understanding and management of these systems: (1) Studies should focus on the watershed, rather than isolated reaches, (2) researchers should strive to attain a better understanding of ecosystem function and the services provided by urban streams to justify management and restoration efforts, and (3) studies that integrate economic models where downstream users pay for upstream protection and restoration could prove beneficial for many Latin American cities in attempting to address water conservation issues.