Estimation Of Vulnerability Research Articles

Local Currency Systemic Risk

Emerging country governments increasingly issue local currency denominated bonds and foreign investors have been increasing their holdings of these assets. By issuing debt denominated in local currency, emerging country governments eliminate exchange rate risk. The growing stock of local currency government debt in the financial portfolios of foreign investors increases their diversification and exposure to fast growing economies. In this paper, we highlight some of the risks associated to this recent trend. First, we adopt the CoVaR risk-measure to estimate the vulnerability of individual countries to systemic risk in the market for local currency government debt. Second, we show that our country-level estimates of vulnerability are higher the larger the share of local currency debt held by foreign investors. A version of the old adage When New York sneezes, London catches a cold, used to describe the relationship between the stock markets in these two cities, still applies between individual emerging countries and the aggregate market for local currency government debt.

Protecting Caches from Soft Errors

Soft error is one of the most important design concerns in modern embedded systems with aggressive technology scaling. Among various microarchitectural components in a processor, cache is the most susceptible component to soft errors. Error detection and correction codes are common protection techniques for cache memory due to their design simplicity. In order to design effective protection techniques for caches, it is important to quantitatively estimate the susceptibility of caches without and even with protections. At the architectural level, vulnerability is the metric to quantify the susceptibility of data in caches. However, existing tools and techniques calculate the vulnerability of data in caches through coarse-grained block-level estimation. Further, they ignore common cache protection techniques such as error detection and correction codes. In this article, we demonstrate that our word-level vulnerability estimation is accurate through intensive fault injection campaigns as compared to block-level one. Further, our extensive experiments over benchmark suites reveal several counter-intuitive and interesting results. Parity checking when performed over just reads provides reliable and power-efficient protection than that when performed over both reads and writes. On the other hand, checking error correcting codes only at reads alone can be vulnerable even for single-bit soft errors, while that at both reads and writes provides the perfect reliability.

2014 Canadian Geotechnical Colloquium: Landslide runout analysis — current practice and challenges

Flow-like landslides, such as debris flows and rock avalanches, travel at extremely rapid velocities and can impact large areas far from their source. When hazards like these are identified, runout analyses are often needed to delineate potential inundation areas, estimate risks, and design mitigation structures. A variety of tools and methods have been developed for these purposes, ranging from simple empirical–statistical correlations to advanced three-dimensional computer models. This paper provides an overview of the tools and methods that are currently available and discusses some of the main challenges that are currently being addressed by researchers, including the need for better guidance in the selection of model input parameter values, the challenge of translating model results into vulnerability estimates, the problem with too much initial spreading in the simulation of certain types of landslides, the challenge of accounting for sudden channel obstructions in the simulation of debris flows, and the sensitivity of models to topographic resolution and filtering methods.

Reliability of the VESPA Index in Identifying Spring Vulnerability Level

To assess spring vulnerability level, the vulnerability estimator for spring protection areas (VESPA) index has been proposed. The VESPA index method is based on the joint use of discharge, electrical conductivity, and temperature data, measured at the spring location. In this paper the VESPA index method has been examined through the analysis of observed time series with respect to the following aspects: (1) the time extension of the data set, (2) the use of averaged data, and (3) the number of missing data. For this purpose four springs fed by different geological systems were considered. The outcomes of the statistical analysis show that the VESPA index is a reliable way to identify higher vulnerability levels while some uncertainty occurs in the identification of low and medium vulnerability levels.

Visualization of xylem embolism by X‐ray microtomography: a direct test against hydraulic measurements

X-ray microtomography (microCT) is becoming a valuable noninvasive tool for advancing our understanding of plant-water relations. Laboratory-based microCT systems are becoming more affordable and provide better access than synchrotron facilities. However, some systems come at the cost of comparably lower signal quality and spatial resolution than synchrotron facilities. In this study, we evaluated laboratory-based X-ray microCT imaging as a tool to nondestructively analyse hydraulic vulnerability to drought-induced embolism in a woody plant species. We analysed the vulnerability to drought-induced embolism of benchtop-dehydrated Eucalyptus camaldulensis plants using microCT and hydraulic flow measurements on the same sample material, allowing us to directly compare the two methods. Additionally, we developed a quantitative procedure to improve microCT image analysis at limited resolution and accurately measure vessel lumens. Hydraulic measurements matched closely with microCT imaging of the current-year growth ring, with similar hydraulic conductivity and loss of conductivity due to xylem embolism. Optimized thresholding of vessel lumens during image analysis, based on a physiologically meaningful parameter (theoretical conductivity), allowed us to overcome common potential constraints of some lab-based systems. Our results indicate that estimates of vulnerability to embolism provided by microCT visualization agree well with those obtained from hydraulic measurements on the same sample material.

Levee body seepage: a refinement of an expeditious procedure for fragility curves and vulnerability diagrams’ assessment

Extensive flooding can be the result of levee system failures most frequently caused by the piping process due to seepage. The proper description of the seepage line is affected by the difficulty of estimating the hydraulic parameters, mainly the soil hydraulic conductivity. Therefore, the development of simple methods for a quick analysis of extended levee systems is fundamental to identify critical points. In this context, a practical procedure, recently proposed, based on a simple vulnerability index is here enhanced and used to derive diagrams easily applicable for seepage vulnerability estimate, taking the hydraulic parameters’ uncertainty into account. The procedure is applied for the Tiber River, in central Italy, and the Tanaro River, in northern Italy, by analyzing 67 and 6 levees, respectively. The results show that the method provides the highest seepage probabilities for levees affected by failures in the past. Therefore, the procedure seems to be able to identify the levees that require detailed investigations. Finally, the Italian levee database (DANTE) is presented as a dynamic geospatial tool for collecting all the available data/information on levee systems to usefully support authorities with the charge of hydraulic risk mitigation for identifying the most vulnerable levees.

Índice de vulnerabilidad costera del litoral tabasqueño, México

Sea level rise is one of the most serious events that will impact low-lying lands, as is the case of most of Tabasco State. Historically, the State of Tabasco has been repeatedly impacted by extreme floods, the most recent one occurring in 2007. However, recent studies have shown that coastal erosion is the effect that most directly has impacted the Tabasco's coastline, as this has even modified soil strata; this is also related to extreme hydrometeorological events associated with environmental changes and changes in the salinity gradient off the coast. In such a situation, future changes in the coastline are almost certain. Tabasco's coastline has been recognized as one of the most vulnerable zones in the country since Mexico's first national communication to the unfccc in 1997. Therefore, it is important to evaluate the vulnerability of this zone. The purpose of this study was to estimate the vulnerability of the Tabasco's coastline by applying the coastal vulnerability index method (ivm) using a geographic information system (gis). This method has been successfully applied in several different places around the world including Canada, the United State, Spain and Indonesia. This model is suitable for the local conditions of Tabasco coast, as the input variables it requires (including waves, tides, sea level, coastal slope, erosion rates and geomorphology) are available for the study area, thus allowing the possibility of estimating the coast's vulnerability based on local data. Results from map algebra operations showed that the zones of very high or high vulnerability encompass a six-kilometer stretch around the Sánchez Magallanes community, near the del Carmen lagoon in the municipality of H. Cárdenas, Tabasco. This is due to the high-waves regime and other conditions associated to the coastal dune geomorphology as well as the unconsolidated fine sediments prevailing therein. Other high vulnerability zones are found just in front of the major lagoon system in the State of Tabasco, the Carmen-Pajonal-Machona and Mecoacan lagoons; being the last one the most vulnerable of all. It is worth pointing out that this zone is located within the influence zone of the Dos Bocas port where an intense anthropogenic activity occurs. It is also important to point out that this study is one of the first approaches to the estimation of coastal vulnerability in Mexico. The implementation and application of this model of coastal vulnerability evaluation are significant given the spatial scale of the study and that this is the first time that these variables have been collected for the state of Tabasco. Our results might inform decision-making processes on the proper management of the Tabasco coastline, thus benefiting the local communities.

Estimating building vulnerability to volcanic ash fall for insurance and other purposes

Volcanic ash falls are one of the most widespread and frequent volcanic hazards, and are produced by all explosive volcanic eruptions. Ash falls are arguably the most disruptive volcanic hazard because of their ability to affect large areas and to impact a wide range of assets, even at relatively small thicknesses. From an insurance perspective, the most valuable insured assets are buildings. Ash fall vulnerability curves or functions, which relate the magnitude of ash fall to likely damage, are the most developed for buildings, although there have been important recent advances for agriculture and infrastructure. In this paper, we focus on existing vulnerability functions developed for volcanic ash fall impact on buildings, and apply them to a hypothetical building portfolio impacted by a modern-day Tambora 1815 eruption scenario. We compare and contrast the different developed functions and discuss some of the issues surrounding estimation of potential building damage following a volcanic eruption. We found substantial variability in the different vulnerability estimates, which contribute to large uncertainties when estimating potential building damage and loss. Given the lack of detailed and published studies of building damage resulting from ash fall this is not surprising, although it also appears to be the case for other natural hazards for which there are far more empirical damage data. Notwithstanding the potential limitations of some empirical data in constraining vulnerability functions, efforts are required to improve our estimates of building damage under ash fall loading through the collection of damage data, experimental testing and perhaps theoretical failure analysis. For insurance purposes, the current building typologies provided for use with vulnerability functions are too detailed to map to the relatively limited information on building types that is typically available to insurers. Thus, efforts to provide vulnerability functions that can be used where only limited information is available regarding building types would also be valuable, both for insurers and for at-risk areas that have not been subject to detailed building vulnerability surveys.

Site dependence and record selection schemes for building fragility and regional loss assessment

SummaryWhen performing loss assessment of a geographically dispersed building portfolio, the response or loss (fragility or vulnerability) function of any given archetype building is typically considered to be a consistent property of the building itself. On the other hand, recent advances in record selection have shown that the seismic response of a structure is, in general, dependent on the nature of the hazard at the site of interest. This apparent contradiction begs the question: Are building fragility and vulnerability functions independent of site, and if not, what can be done to avoid having to reassess them for each site of interest? In the following, we show that there is a non‐negligible influence of the site, the degree of which depends on the intensity measure adopted for assessment. Employing a single‐period (e.g., first‐mode), spectral acceleration would require careful record selection at each site and result to significant site‐to‐site variability of the fragility or vulnerability function. On the other hand, an intensity measure comprising the geometric mean of multiple spectral accelerations considerably reduces such variability. In tandem with a conditional spectrum record selection that accounts for multiple sites, it can offer a viable approach for incorporating the effect of site dependence into fragility and vulnerability estimates. Copyright © 2017 John Wiley & Sons, Ltd.

発育予測モデルとメッシュ気象データを利用したダイズの乾燥ストレス発生リスクの広域評価

発育予測モデルとメッシュ気象データを利用したダイズの乾燥ストレス発生リスクの広域評価

Vulnerability of nearshore tropical finfish in Cuba: implications for scientific and management planning

Coastal areas of Cuba harbor rich biodiversity that provide a variety of important ecosystem services, including fisheries production. High-value invertebrate fisheries in Cuba are managed on the basis of scientific assessments, but comparable data and analyses are lacking for the much larger number of exploited finfish species. However, dramatic declines in finfish catch despite minimal management restrictions suggests resource depletion, and the need for scientific and management attention. To prioritize finfish for such attention, we conducted productivity-susceptibility analyses (PSA) for 34 species within each of Cuba's four fishery management zones. The resulting 136 estimates of vulnerability to overfishing revealed few differences in species-specific scores among zones, despite ecological and socioeconomic heterogeneity along the Cuban coast. Vulnerability scores were generally low, although this relative metric does not necessarily mean that overfishing has not occurred. Spatial differences in catch composition relative to the vulnerability scores underscore potential differences in socioeconomic vulnerability of fishing communities based upon their reliance on different species. Therefore, our PSA results should be used to prioritize research, monitoring, and stock assessment efforts, as well as management actions, within each fishing zone to conserve locally important resources, recover those that are depleted, sustainably develop those that are underutilized, and promote ecological and socioeconomic stability across Cuba as it confronts the challenges of a changing world.

Environmental factors affecting burrowing by brown shrimp Farfantepenaeus aztecus and white shrimp Litopenaeus setiferus and their susceptibility to capture in towed nets

Laboratory experiments were conducted under simulated daytime conditions to examine the effects of salinity, sediment texture, size, density, and hunger on burrowing behavior of juvenile brown shrimp Farfantepenaeus aztecus and white shrimp Litopenaeus setiferus. Over all experimental conditions (20,929 observations of 2411 individual shrimp), 77.5% of brown shrimp and 21.4% of white shrimp were observed burrowed with more than half of their body beneath the substrate. The tendency of burrowed shrimp to emerge from burrows when disturbed also was tested. When burrowing rates were examined in combination with this tendency to emerge upon disturbance, only 46.7% of brown shrimp would be susceptible to capture in towed nets, while almost all (97%) white shrimp would be susceptible. All environmental factors examined in this study, except salinity for white shrimp, significantly affected burrowing of these species. When these environmental effects on burrowing were combined with the likelihood of emergence, however, the effects of salinity and substrate type on brown shrimp behavior appeared most likely to affect capture by towed nets. Estuarine abundance indices from resource surveys using towed nets could be adjusted using such vulnerability estimates.

Financial imperfections, product quality, and international trade

We study how financial imperfections affect product quality across countries and industries, and analyze the implications for trade flows and prices. To this purpose we assemble a unique data set, which contains estimates of export quality, financial development, and financial vulnerability, for all countries and manufacturing industries over the last three decades. We find the interplay between cross-country differences in financial frictions and cross-industry differences in financial vulnerability to be an important determinant of the geographical and sectoral variation in average product quality. We show that this effect mostly occurs along an intensive margin, whereby financial imperfections distort the quality of existing exports to a given destination market. Finally, we provide evidence that quality adjustments are an important mechanism through which financial development shapes the variation in trade flows and export prices across countries and industries.

X-ray microtomography observations of xylem embolism in stems of Laurus nobilis are consistent with hydraulic measurements of percentage loss of conductance.

Drought-induced xylem embolism is a serious threat to plant survival under future climate scenarios. Hence, accurate quantification of species-specific vulnerability to xylem embolism is a key to predict the impact of climate change on vegetation. Low-cost hydraulic measurements of embolism rate have been suggested to be prone to artefacts, thus requiring validation by direct visualization of the functional status of xylem conduits using nondestructive imaging techniques, such as X-ray microtomography (microCT). We measured the percentage loss of conductance (PLC) of excised stems of Laurus nobilis (laurel) dehydrated to different xylem pressures, and compared results with direct observation of gas-filled vs water-filled conduits at a synchrotron-based microCT facility using a phase contrast imaging modality. Theoretical PLC calculated on the basis of microCT observations in stems of laurel dehydrated to different xylem pressures overall were in agreement with hydraulic measurements, revealing that this species suffers a 50% loss of xylem hydraulic conductance at xylem pressures averaging -3.5MPa. Our data support the validity of estimates of xylem vulnerability to embolism based on classical hydraulic techniques. We discuss possible causes of discrepancies between data gathered in this study and those of recent independent reports on laurel hydraulics.

A Hybrid Approach for Path Vulnerability Matrix on Random Key Predistribution for Wireless Sensor Networks

In this paper, we address the problem of physical node capture attack from an adversarial view. In this type of attack, an adversary intelligently captures the node(s) and extracts the cryptographic information to destroy the privacy, safety and reliability of the network. We propose a novel hybrid approach for constructing the path vulnerability matrix that maximizes the attacking efficiency and lowers the resource expenditure of the adversary. The main strength of the proposed matrix lies in incorporating various criteria such as the type of application running on the nodes, capturing cost, key dominance ranking, articulation point and intersecting shortest path nodes in estimating the vulnerability. The location of the data sink is considered as a major factor in estimating the vulnerability of the nodes in the network. The proposed matrix is compared with existing attacking strategies in terms of the number of attacking rounds, energy cost and fraction of compromised traffic. Although in this paper, we have considered adversarial point of view but the proposed matrix can be extended for the defender application also. The path vulnerability matrix provides vulnerability estimation that can be used to analyze system security weakness and helps to defend against them effectively and efficiently. The performance of proposed approach has been validated with respect to average path compromise ratio, average routing path length and average route successful ratio. We have also introduced an attack resistant random key predistribution scheme based on the proposed approach and the results confirm its effectiveness in decreasing node capture impact.

Toward early estimation and treatment of addiction vulnerability: radial arm maze and N-acetyl cysteine before cocaine sensitization or nicotine self-administration in neonatal ventral hippocampal lesion rats.

RationalPrefrontal cortical (PFC)–hippocampal–striatal circuits, interconnected via glutamatergic signaling, are dysfunctional in mental illnesses that involve addiction vulnerability.ObjectivesIn healthy and neurodevelopmentally altered rats, we examined how Radial Arm Maze (RAM) performance estimates addiction vulnerability, and how starting a glutamatergic modulating agent, N-acetyl cysteine (NAC) in adolescence alters adult mental illness and/or addiction phenotypes.MethodsRats with neonatal ventral hippocampal lesions (NVHL) vs. SHAM-operated controls were randomized to NAC vs. saline in adolescence followed by cognitive testing (RAM) in early adulthood and then cocaine behavioral sensitization (experiment 1; n = 80) or nicotine self-administration (experiment 2; n = 12).ResultsIn experiment 1, NVHL rats showed over-consumption of food (Froot-Loops (FL)) baiting the RAM with poor working memory (low-arm entries to repeat (ETR)), producing an elevated FL to ETR ratio (“FLETR”; p < 0.001). FLETR was the best linear estimator (compared to FL or ETR) of magnitude of long-term cocaine sensitization (R 2 = 0.14, p < 0.001). NAC treatment did not alter FL, ETR, FLETR, or cocaine sensitization. In experiment 2, FLETR also significantly and uniquely correlated with subsequent drug seeking during nicotine-induced reinstatement after extinction of nicotine self-administration (R 2 = 0.47, p < 0.01). NAC did not alter RAM performance, but significantly reversed NVHL-induced increases in nicotine seeking during extinction and reinstatement.ConclusionsThese findings demonstrate the utility of animal models of mental illness with addiction vulnerability for developing novel diagnostic measures of PFC–hippocampal–striatal circuit dysfunction that may reflect addiction risk. Such tests may direct pharmacological treatments prior to adulthood and addictive drug exposure, to prevent or treat adult addictions.

Counting the cost of coastal vulnerability

Significant coastal vulnerability (CV) in the United Kingdom (UK) endangers the population and the infrastructure and distorts the national economy, yet present and proposed literature only quotes previous circumstances that failed to deliver factual fiscal assessment. The current estimate models for coastal vulnerability are useful for decision-making in some magnitudes, but coastal vulnerability models need to be extended to comprise a wider choice of economic effects. These are real problems that need to be addressed for an estimation of fiscal coastal vulnerability with novel models of science and economics to limit destruction costs or spend with greater resilience. To address the current research gap, this study appraised coastal vulnerability by establishing an innovative model: a Fiscal Coastal Vulnerability Index (FCVI) with fiscal parameters by 2 Path analysis (2 PA). It identifies the coastal vulnerability hotspots in Path One (P1) and develops an FCVI and GIS maps in Path Two (P2). Primary results revealed that 11 sites across the UK (seven in England, three in Wales, and one in Scotland) were identified as fiscally vulnerable coastal areas. Identified sites currently contain £22.36 billion worth of coastal vulnerability, and >100,000 people are at high risk of flooding, erosion, storm surge, and high winds. The Fiscal Coastal Vulnerability Index can be adapted depending on kind of coastal environment and used as a planning tool to establish economic susceptibility. This work explains that the methodological framework can be adjusted for any suitable coastal sites at global or regional scales, and can be used to vindicate in-depth studies for coastal defences and budget.

Anatomía, índices físicos e hidráulicos de la madera de Gliricidia sepium (Jacq.) Steud.

Se presentan los resultados de un estudio de la variación anatómica y de los índices físicos e hidráulicos de la madera de albura y duramen de seis árboles de Gliricidia sepium ( Jacq.) Steud. colectados en épocas de secas y lluvias de una selva baja de Veracruz, México. De rodajas cortadas a 1 ,30 m del suelo, se hicieron probetas de diversos tamaños para estudiar el contenido de humedad, la densidad relativa y la anatomía macroscópica y microscópica. Se usaron cubos con los que se elaboraron preparaciones fijas de cortes y material disociado, siguiendo los protocolos clásicos de laboratorio, así como las clasificaciones y nomenclaturas internacionales para los elementos celuusando el diámetro, la densidad y el área efectiva de vasos. Los análisis de varianza y de compolares. Los cálculos de índices de vulnerabilidad, de resistencia al colapso y K h-teórica se hicieron nentes principales mostraron que las diferencias entre árboles, zonas y estaciones están dadas por algunas características de las fibras, los vasos, los radios y las punteaduras. Aunque la variación en estas características es baja, explicaría la estabilidad dimensional de la albura y el duramen a los cambios de régimen hídrico ocasionados por la sequía y la lluvia. Los índices de resistencia al colapso pero con mucho éxito para desarrollarse en ambientes perturbados, lo que podría estar explicado por y de vulnerabilidad, así como la K h muestran un xilema mesomórfico muy vulnerable a embolismos, la presencia de tílides, abundante parénquima axial y valores altos de la densidad relativa que aseguran resistencia de las paredes de los vasos y fibras al colapso.

Unreinforced masonry walls with irregular opening layouts: reliability of equivalent-frame modelling for seismic vulnerability assessment

Equivalent-frame modelling for the estimate of in-plane seismic vulnerability of masonry wall is endorsed by international codes. However, in presence of irregular layouts of openings, the definition of equivalent-frame becomes non-unique and may lead to epistemic modelling errors. The aim of this paper is to develop a simplified tool to estimate such errors as functions of the level or geometric irregularity. Four types of irregularity are considered and quantified by geometric indexes. Nonlinear static analyses are carried out through an equivalent-frame model and a nonlinear finite-element model. It is assumed that both models are exact for perfectly-regular walls, while in presence of irregularities only the continuum approach is able to correctly predict the vulnerability, so that the difference between the two results can be taken as a measure of the error of the equivalent frame. A regular wall is taken as case study and both numerical models are calibrated on experimental data. The four typologies of irregularity are introduced separately, each in steps of increasing magnitude. The results show that the equivalent frame approach is usually not safety-preserving and may be affected by a significant error. A tentative global measure of irregularity, weighting the average effects of each irregularity type, is proposed. The resulting simplified relationship between irregularity level and expected error can be used to define a confidence factor on the modelling, which penalizes the application of the equivalent frame in case of irregular walls. Eventually, an applicability limit of the equivalent-frame model might be set.

Prioritization maps: The integration of environmental risks to manage water quality in harbor areas

A method to integrate the environmental risk of the multiple effects from uses and activities developed in harbor areas is presented. Consequences are considered as the effects derived from all identified hazards. Vulnerability is expressed in terms of functional relations between environmental susceptibility against a disturbance and the state of protection of the receptors at risk. Consequences and vulnerability are integrated obtaining a spatial variation of risk: prioritization maps. The maps are developed by 4 main stages: (1) environmental hazard identification; (2) estimation of the consequences; (3) estimation of vulnerability and, (4) integration of environmental risks. To adapt prioritization maps to the peculiarities of the study area, three different methods for the integration of the effects are proposed: average-value, worst-case and weighted methods. The implementation to a real case (Tarragona harbor, NE Spain) confirms its usefulness as a risk analysis tool to communicate and support water quality management in harbors.