Benthic monitoring and sampling design and effort to detect spatial changes: A case study using data from offshore wind farm sites

© 2015 Elsevier Ltd. All rights reserved. The exploitation of renewable energies, in particular offshore wind farms (OWFs), is an expanding sector which involves activities that may adversely affect the marine benthic ecology. Fit-for-purpose monitoring is required with sufficient statistical power to detect ecologically meaningful changes, but to date there have been no studies on the suitability of monitoring programmes applied to OWFs. The theoretical relationship of sampling effort with precision in community estimates and sensitivity of the analysis in detecting spatial changes was investigated, this latter assessed through power analysis. Benthic community monitoring strategies and descriptors applied to UK OWFs were used to interrogate real data variability in the marine environment. There was a general lack of clarity in the survey rationale and hypotheses tested within OWF monitoring programmes hence a lack of rigour in the survey design and statistical testing. Consequently the statistical properties of monitoring strategies have been rarely assessed. Precision of mean estimates of benthic community descriptors and the sensitivity in detecting differences in the means increased with sampling effort. At the average sampling effort applied in the OWF case studies (4 stations per impact type area and 3 replicates per station), the studies had sufficient power to detect a ≥50% change between areas in mean benthic species richness (S; 5 species). Due to their higher variability than S, more stations per impact type area were required to reliably detect a ≥50% change between areas in mean benthic abundance (N; 5 stations) and mean biomass (B; 10 stations). Higher sensitivity and precision of estimates of S, N and B was achieved with transformation of data. Understanding the general implications of monitoring design on the sensitivity of the detection of spatial changes is important, particularly when monitoring effort has to be adjusted due to logistic and financial constraints. Although there is no 'one-size-fits-all' approach to marine environmental data acquisition, this study guides researchers, developers and regulators in optimising benthic monitoring strategies at OWFs

JPEG linked media format (JLINK) applications

The growing and emerging of the large use of images in recent decades has fostered the need to innovate with new functionalities and applications. That is the reason why the Joint Photographic Experts Group (JPEG) is currently developing new standards. This thesis focuses on the JPEG Systems Part 7: JPEG Linked Media Format (JLINK) standard, which aims to allow a set of related images to be encapsulated in a single, and, through an adapted viewer, to move between images through interactive points. The main objective of the project is to implement an application that allows to create, visualize and modify this type of files defined by the specifications of the standard. The result has been a web application capable of performing the aforementioned actions, with the addition of more functions. It also has a database to have control of the stored files. The usefulness of defining a standard has been proven, and the importance of developers to check that the specifications given are correct or need to be modified.El creciente y emergente uso de imágenes en las últimas décadas ha fomentado la necesidad de innovar con nuevas funcionalidades y aplicaciones. Por ello, el Joint Photographic Experts Group (JPEG) está desarrollando actualmente nuevos estándares. Esta tesis se centra en el estándar JPEG Systems Part 7: JPEG Linked Media Format (JLINK), que pretende permitir encapsular un conjunto de imágenes relacionadas en una sola, y, a través de un visor adaptado, moverse entre las imágenes mediante puntos interactivos. El objetivo principal del proyecto es implementar una aplicación que permita crear, visualizar y modificar este tipo de archivos definidos por las especificaciones del estándar. El resultado ha sido una aplicación web capaz de realizar las acciones mencionadas, con el añadido de más funciones. También dispone de una base de datos para tener el control de los ficheros almacenados. Se ha comprobado la utilidad de la definición de un estándar y la importancia de que los desarrolladores comprueben que las especificaciones dadas son correctas o deben ser modificadas.El creixement i l'aparició de l'ampli ús de les imatges a les darreres dècades ha fomentat la necessitat d'innovar amb noves funcionalitats i aplicacions. Per això, el Joint Photographic Experts Group (JPEG) està desenvolupant actualment nous estàndards. Aquesta tesi se centra en l'estàndard JPEG Systems Part 7: JPEG Linked Media Format (JLINK), que pretén permetre encapsular un conjunt d'imatges relacionades en una de sola, i, mitjançant un visor adaptat, moure's entre les imatges mitjançant punts interactius. L'objectiu principal del projecte és implementar una aplicació que permeti crear, visualitzar i modificar aquest tipus de fitxers definits per les especificacions de l'estàndard. El resultat ha estat una aplicació web capaç de fer les accions esmentades, amb l'afegit de més funcions. També disposa d'una base de dades per tenir el control dels fitxers emmagatzemats. S'ha comprovat la utilitat de la definició d'un estàndard i la importància que els desenvolupadors comprovin que les especificacions donades són correctes o s'han de modificar

The Welfare Cost of Macroeconomic Uncertainty in the Post-War Period

Lucas (1987) has shown the surprising result that the welfare cost of business cycles is quite small. Using standard assumptions on preferences and a fully-fledged econometric model we computed the welfare costs of macroeconomic uncertainty for the post-WWII era using the multivariate Beveridge-Nelson decomposition for trends and cycles, which considers not only business-cycle uncertainty but also uncertainty from the stochastic trend in consumption. The post-WWII period is relatively quiet, with the welfare costs of uncertainty being about 0.9% of per-capita consumption. Although changing the decomposition method changed substantially initial results, the welfare cost of uncertainty is qualitatively small in the post-WWII era - about $175.00 a year per-capita in the U.S. We also computed the marginal welfare cost of macroeconomic uncertainty using this same technique. It is about twice as large as the welfare cost -$350.00 a year per-capita.welfare costs of business cycles, Beveridge-Nelson decomposition

On the Welfare Costs of Business-Cycle Fluctuations and Economic-Growth Variation in the 20th Century

Lucas (1987) has shown a surprising result in business-cycle research: the welfare cost ofbusiness cycles are very small. Our paper has several original contributions. First, in computingwelfare costs, we propose a novel setup that separates the effects of uncertainty stemming frombusiness-cycle fluctuations and economic-growth variation. Second, we extend the sample from which to compute the moments of consumption: the whole of the literature chose primarily to work with post-WWII data. For this period, actual consumption is already a result of counter-cyclical policies, and is potentially smoother than what it otherwise have been in their absence. So, we employ also pre-WWII data. Third, we take an econometric approach and compute explicitly the asymptotic standard deviation of welfare costs using the Delta Method. Estimates of welfare costs show major differences for the pre-WWII and the post-WWII era. They can reach up to 15 times for reasonable parameter values -β=0.985, and ∅=5. For example, in the pre-WWII period (1901-1941), welfare cost estimates are 0.31% of consumption if we consider only permanent shocks and 0.61% of consumption if we consider only transitory shocks. In comparison, the post-WWII era is much quieter: welfare costs of economic growth are 0.11% and welfare costs of business cycles are 0.037% - the latter being very close to the estimate in Lucas (0.040%). Estimates of marginal welfare costs are roughly twice the size of the total welfare costs. For the pre-WWII era, marginal welfare costs of economic-growth and business- cycle fluctuations are respectively 0.63% and 1.17% of per-capita consumption. The same figures for the post-WWII era are, respectively, 0.21% and 0.07% of per-capita consumption.