311 research outputs found

    Substituting model based indicators in Harvest Control Rules by observations using fuzzy logic methodology

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    The accepted manuscript (AM) is the final draft author manuscript, as accepted for publication by a journal, including modifications based on referees’ suggestions, before it has undergone copyediting, typesetting and proof correction. This is sometimes referred to as the post-print version. Source at: http://doi.org/10.1093/icesjms/fsx227Harvest Control Rules are predefined heuristic decision rules to provide quota advices for managed fisheries. Frequently statistical methods and biological assumptions expressed in mathematical models, are used to provide the Harvest Control Rules with initial information (indicators values). The aim of this article is to investigate a possible way forward of replacing these inputs by quantities of measurable observations, e.g. catch-at-age statistics. The article presents a method by which recruitment indexes and stock biomass indicators are obtained by non-parametric use of annual catch-at-age records, without filtering the raw data (observations) through mathematical models. Two related methods, applied on three empirical cases, are provided: First, showing that recruitment strengths of the Northeast Arctic cod, haddock, and saithe stocks, obtained by fuzzy logic methodology, are satisfactory captures by the use of catch-at-age data. Second, stock size indicators are estimated for the three species by the same catch-at-age data. The second task turns out to be more challenging than the first, but also in the case of stock size evaluation, the suggested procedure provides reasonable results when compared to standard stock assessment method

    HARVEST FUNCTIONS: THE NORWEGIAN BOTTOM TRAWL COD FISHERIES

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    A detailed and comprehensive set of catch and effort data for the cod fisheries of 18 Norwegian bottom trawlers have been obtained for the period 1971–85, a period with few binding quota restrictions on vessel operations. Harvest functions have been designed and estimated. The independent variables are hours of trawling per vessel day and biomass of the cod stock (3+). Daily biomass estimates have been calculated by polynomial interpolation of the annual estimates of the International Council for the Exploration of the Sea (ICES). By maximizing the log-likelihood function using numerical methods, parameter estimates and performance indicators of the different models were obtained. The best result was obtained for a harvest model allowing for seasonal changes and with an autocorrelated error term. For this model, the stock-output elasticity is estimated at 0.424, the effort-output elasticity at 1.232, and the technological change at about a 2% annual increase in productivity. The seasonal changes in catchability are significant, with the lowest intra-annual catchability being less than 30% of the annual maximum.Resource /Energy Economics and Policy,

    Disability and Poverty

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    This book is about being disabled and being poor and the social, cultural and political processes that link these two aspects of living in what has been characterised as a “vicious circle” (Yeo & Moore 2003). It is also about the strengths that people show when living with disability and being poor. How they try to overcome their problems and making the best out of what little they have. This book will appeal to academics, postgraduates and policymakers in disability studies, development studies, poverty and social exclusion

    Space – det 5. operasjonsdomenet: En styrkemultiplikator for Hærens kampkraft?

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    I 2019 ble Space erklært som et nytt militært operasjonsdomene i NATO. Samme år godkjente Forsvarssjef (FSJ) admiral Haakon Bruun-Hanssen operasjonalisering av romdomenet i Forsvaret. Forarbeidet til dette startet allerede med FSJ anbefaling i FMR 2015. Anbefalingen gikk ut på å øke bruken av satellitter i nordområdene og etablere Program Space i Forsvarsdepartementet. Program Space sin hovedoppgave var å utarbeide en plan for koordinert ledelse av Forsvarets romvirksomhet. (Fauske & Strand, 2022, s. 17). I 2020 ble Program Space flyttet til Forsvarsstaben (FST), og Forsvarets romvirksomhet var da en realitet. Hæren bruker daglig rombasert teknologi, og kampplattformene har blitt mer høyteknologiske og avhengige av romdomenet for å fungere optimalt. Teknologiutviklingen akselererer i et forrykende tempo og informasjonstilfanget fra rombaserte tjenester er enormt. Derimot har ikke Hæren enda helt klart å forstå mulighetene og begrensningene det nye domenet gir. Spesielt ikke hva bortfall av teknologien vil gjøre med stridsfeltet og manøveren i operasjonen. Derfor har jeg i denne oppgaven valgt å ta for meg hvordan Hæren kan implementere og utnytte rombasert teknologi for å styrke kampkraften. Gjennom undersøkelsen har jeg ikke kommet over annen forskning som omhandler Hærens relasjon til romdomenet. De 12 intervjuobjektene var derfor helt essensielle for å få en solid bredde på empirien. I prosessen med bearbeidelsen av innsamlet empiri, var det spesielt fire faktorer som krystalliserte seg som meget avgjørende for Hæren i møte med romdomenet og styrking av egen kampkraft. Disse faktorene er lederstøtte, beslutningstaking, samvirke og konsekvenser ved bortfall og kompetanse. Sistnevnte faktor viser seg å være kjernen i arbeidet med problemstillingen og de fem forskningsspørsmålene. Det er et stort kompetansegap i Hæren, og det kan med bakgrunn i oppgavens funn hevdes at det er tidskritisk å få tettet disse hullene. Hæren er både positiv til, og motivert for et tettere samarbeid med Forsvarets romvirksomhet. Det er en felles enighet om at implementering og utnyttelse av romdomenet vil gi fordeler på stridsfeltet. Å ha tilgang til et tilnærmet kontinuerlig oppdatert situasjonsbilde vil spare tid i beslutningssløyfen, og gi en styrket fordel i favør av fienden. Trekantsamarbeidet mellom Forsvaret, Forsvarets forskningsinstitutt og sivil industri øker innovasjonstempoet, og gir organisasjonen tilganger til både nasjonale og allierte evner. Vår geostrategiske plassering og innovative utvikling innenfor romdomenet gjør oss til en viktig alliert i NATO. Undersøkelsens empiri gir et overordnet og tydelig signal om at det 5. operasjonsdomenet, Space, er en styrkemultiplikator for Hærens kampkraft

    Using prospective methods to identify fieldwork locations favourable to understand divergences in health care accessibility

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    Central to this article is the issue of choosing sites for where a fieldwork could provide a better understanding of divergences in health care accessibility. Access to health care is critical to good health, but inhabitants may experience barriers to health care limiting their ability to obtain the care they need. Most inhabitants of low-income countries need to walk long distances along meandering paths to get to health care services. Individuals in Malawi responded to a survey with a battery of questions on perceived difficulties in accessing health care services. Using both vertical and horizontal impedance, we modelled walking time between household locations for the individuals in our sample and the health care centres they were using. The digital elevation model and Tobler’s hiking function were used to represent vertical impedance, while OpenStreetMap integrated with land cover map were used to represent horizontal impedance. Combining measures of walking time and perceived accessibility in Malawi, we used spatial statistics and found spatial clusters with substantial discrepancies in health care accessibility, which represented fieldwork locations favourable for providing a better understanding of barriers to health access.publishedVersio
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