Spelling suggestions: "subject:"mmf"" "subject:"fmf""
11 |
Climate change impact on probable maximum precipitation and probable maximum flood in Québec / Les effets du changement climatique sur la pluie maximale probable et la crue maximale probable au QuébecRouhani, Hassan January 2016 (has links)
Abstract : As atmospheric temperatures at the Earth’s surface increase due to global warming, the capacity of lower atmospheric levels to hold water vapor rises and thus, precipitations and floods will be influenced. In turn, extreme precipitation and flood events are subject to potential modifications under climate change, namely, Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF). This research aims at analyzing climate change influences on PMP and PMF in three watersheds with different climatic conditions across the province of Québec, Canada. The watersheds are located in the south, center and north of the province. They have been selected in a manner which reflects climate diversity across Québec.
In order to study climate change conditions, the data output of the Canadian Regional Climate Model (CRCM) was used. This database covers a time horizon from 1961 up to 2100 and includes daily precipitation, temperature, specific humidity and Convective Available Potential Energy (CAPE). These data were used to estimate PMP. The World Meteorological Organization (WMO) method was adapted to estimate PMP values under climate change conditions. The 100-year return period precipitable water (W100) was selected as an upper limit of precipitable water in establishing maximization ratio. The time series for estimating W100 was established from annual maximum precipitable water values that have similar atmospheric variables of the event to be maximized. The atmospheric variables used in this research were atmospheric temperature at the Earth’s surface and CAPE. This method does not require setting any upper bound limit to the maximization ratio and is therefore more amenable to calculate the PMP in a climate change context.
The PMP was used to run a distributed hydrological model to estimate PMF. PMP and PMF values were estimated in three 45-year time horizons: recent past (centered on 1985), near future (2030) and far future (2070). In regions where snowmelt plays a key role in the annual hydrological cycle, winter-spring flooding could be the major discharge. Consequently, PMP and PMF were separately analyzed in two seasons: summer-fall (snow-free) and winter-spring (snow accumulation and melt). The largest value obtained was identified as the all-season PMP/PMF. Summer-fall PMF was estimated by inserting the PMP in each day of the simulated time horizon. Therefore, all soil moisture conditions prior to PMP occurrence were included. Accordingly, a distribution of PMF values based on different initial conditions (soil wetness levels) was obtained. Winter-spring PMF was estimated by inserting the PMP value at the end of a warm melting period and for an extreme snow accumulation.
Our results show that the PMF of three watersheds would occur in the winter-spring season in current and future climate projections. Furthermore, all-season PMP and PMF in southern Québec would decrease, but trends in central and northern of Québec would be reversed and the PMP and PMF would increase in projected climate conditions. In the center and north of Québec, the PMF would increase by 25 and 23% respectively, at the end of the 21st century. For the same period, PMF would have a reduction of 25% in the south of Québec. Of the three watersheds, the PMF always occurs at the end of winter-spring season when the snow accumulation is the greatest. / Résumé: Quand la température atmosphérique à la surface a des augmentations en raison du réchauffement climatique mondial, la capacité des niveaux atmosphériques inférieurs à contenir de la vapeur d’eau s’élève. Ceci peut influencer les précipitations et les inondations. C’est pourquoi le réchauffement mondial conduit au changement climatique. Les précipitations extrêmes et les inondations extrêmes peuvent potentiellement subir des changements, à savoir, la précipitation maximale probable (PMP) et la crue maximale probable (CMP). Cette recherche vise à analyser les influences du changement climatique sur la PMP et la CMP dans trois bassins versants avec différentes conditions climatiques à travers la province de Québec, Canada. Les bassins versants sont situés dans le sud, le centre et le nord du Québec. Ils ont été sélectionnés d’une manière qui reflète la diversité du climat à travers le Québec.
Afin d'étudier les conditions du changement climatique, les sorties du modèle régional canadien du climat (MRCC) ont été utilisées. Cette base de données couvre un horizon de temps à partir de 1961 jusqu'à 2100. Les données comprennent la précipitation quotidienne, la température, l'humidité spécifique et l’énergie potentielle de convection disponible (EPCD). Ces données ont été utilisées pour estimer la PMP. La méthode de l’Organisation Météorologique Mondiale (OMM) a été adaptée pour estimer les valeurs de la PMP dans des conditions de changements climatiques. L'eau précipitable centennale (W100) a été choisie comme une limite supérieure de l'eau précipitable pour déterminer le rapport de maximisation. Les séries chronologiques pour estimer W100 ont été établies à partir de valeurs annuelles maximales d'eau précipitable qui sont associées à des valeurs de variables atmosphériques similaires à l'événement qui doit être maximisé. Les variables atmosphériques utilisées dans cette recherche sont la température atmosphérique à la surface et l'EPCD. Cette méthode ne nécessite pas de fixer une limite supérieure au rapport de maximisation et est donc plus propice à la détermination de la PMP dans un contexte des changements climatiques.
La PMP résultante a été utilisée pour forcer un modèle hydrologique distribué afin d’estimer la CMP. Les valeurs de la PMP et de la CMP ont été estimées en trois horizons de temps: le passé récent, les futurs proches (2030) et lointains (2070). Dans les régions où la fonte des neiges joue un rôle clé dans le cycle hydrologique annuel, les crues printanières en climat actuel correspondent habituellement au débit maximum annuel. La PMP et la CMP ont cependant été analysées séparément en deux saisons: l'été-automne (sans neige) et l'hiver-printemps (accumulation et fonte de neige) pour évaluer l’impact des changements climatiques sur la saisonnalité de ces événements extrêmes. La plus grande valeur obtenue a été identifiée comme la PMP / CMP annuelle. La CMP d’été-automne a été estimée par l'insertion de la PMP pour chaque jour de l'horizon de temps de simulation. Par conséquent, toutes les conditions possibles d'humidité du sol avant l’événement de la PMP ont été incluses. En conséquence, une distribution des valeurs de CMP basées sur différentes conditions initiales (niveaux d'humidité du sol) a été obtenue. La CMP d’hiver-printemps a été estimée en insérant la valeur de PMP à la fin d'une période de fonte et une accumulation de neige extrême.
Nos résultats montrent que dans le sud et le nord du Québec, la CMP a toujours lieu à la fin de la saison hiver-printemps lorsque l’accumulation de neige est maximale. Aussi, la PMP et la CMP au sud du Québec devraient diminuer, mais la tendance au centre et au nord du Québec serait inversée. Dans le centre et le nord, la CMP augmente de 22 et 21%, respectivement, à la fin du 21e siècle alors que pour la même période, CMP aurait une réduction de 13% dans le sud du Québec. La CMP annuelle de ces bassins versants se produit dans la saison hiver-printemps dans trois horizons temporels.
|
12 |
マレーシアPM2.5の化学性状特性に対するインドネシア泥炭火災の影響藤井, 佑介 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第19819号 / エネ博第325号 / 新制||エネ||65(附属図書館) / 32855 / 京都大学大学院エネルギー科学研究科エネルギー社会・環境科学専攻 / (主査)教授 東野 達, 教授 坂 志朗, 准教授 亀田 貴之 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM
|
13 |
Hydrologic Modeling of a Probable Maximum Precipitation Event Using HEC-HMS and GIS Models - A Case Study of Two Watersheds in Southern Virginia-Kingston, William John III 25 July 2012 (has links)
Presented in this thesis is a case study of two study watersheds located in south central Virginia. For each, a HEC-HMS event-based hydrologic model was constructed to simulate the rainfall-runoff response from the Probable Maximum Storm (PMS), the theoretical worst-case meteorological event that is capable of occurring over a particular region. The primary goal of these simulations was to obtain discharge hydrographs associated with the Probable Maximum Flood (PMF) at key locations in each of the watersheds. These hydrographs were subsequently used to develop flood inundation maps of the study areas and to characterize sediment transport phenomena in the study reaches under severe flooding conditions.
To build the hydrologic basin models, ArcHydro, HEC-GeoHMS and ArcGIS were employed to assimilate the substantial amount of input data and to extract the pertinent modeling parameters required for the selected simulation methods. In this, the SCS Loss and Transform Methods, along with the Muskingum Routing Method, were adopted for the HEC-HMS simulations.
Once completed, the basin models were calibrated through a comparison of simulated design storm flows to frequency discharge estimates obtained with regional regression techniques and a flood frequency analysis. The models were then used to simulate their respective PMS events, which were developed following recommendations from the Hydrometeorological Branch of the National Weather Service and the U.S. Army Corps of Engineers.
Descriptions of each of the study sites, explanations of the modeling theory and development methodologies, and discussions of the modeling results are all detailed within. / Master of Science
|
14 |
Hydraulic Modeling of a River Network for Predicting Flood Inundation using HEC-RAS and GIS Models - A Case Study in Southern VirginiaCastro Bolinaga, Celso Francisco 17 December 2012 (has links)
A flood inundation study is presented for a watershed located in south central Virginia. A HEC-RAS hydrodynamic model of the main river network was developed to assess the impact of a number of hydrologic events, including the Probable Maximum Flood (PMF), in the area of interest. The primary goal of the study was to transform discharge hydrographs produced by HEC-HMS, an event-based hydrologic model, into water surface elevations and flood inundation spatial extents.
Initially, a river terrain model was constructed using data from publicly available sources and filed survey campaigns. HEC-GeoRAS and ArcGIS were used to document and integrate the considerable amount of data required for building the model. Then, a calibration process was performed using stage-discharge predictor curves. The HEC-RAS unsteady flow component was employed for routing the discharge hydrographs through the modeled river network. Flood inundation maps, as well as longitudinal water surface elevation and channel velocity profiles were generated for the study reaches.
As part of the flood inundation study, an uncertainty quantification analysis was carried out on the boundary roughness of the floodplains. The objective was to measure the extent to which flood inundated areas, water surface elevations, and channel velocities were influenced by variations on this empirically-based model coefficient.
Finally, the impact of various hydraulic characteristics of the modeled river on the sediment transport process is examined. This characterization is intended to provide a better understanding of a subsequent sediment transport modeling effort to be performed under severe flooding conditions. / Master of Science
|
15 |
Air Quality and Environmental Impact Assessment of Industrial Activities in East Java, Indonesia / インドネシアジャワ島東部における工業活動による大気汚染と環境影響の評価Diah, Dwiana Lestiani 25 March 2024 (has links)
京都大学 / 新制・論文博士 / 博士(工学) / 乙第13616号 / 論工博第4213号 / (主査)教授 高木 郁二, 教授 佐々木 隆之, 教授 米田 稔 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
|
16 |
Källspårning av PCB med hjälp av kongenmönsterBjerklund, Frida January 2024 (has links)
Polyklorerade bifeneyler (PCB) är en problematisk organisk förorening och består av 209 olikakongener, som sorteras beroende på antal kloratomer och dess position i bifenylmolekylen. Syftet idetta arbete har varit att utveckla studier kring de förhöjda halterna av PCB i två områden med hjälpav kongenmönster för sju av kongenerna - indikatorkongenerna (∑PCB7) - som används som enindikation av totalhalten PCB. Med hjälp av kongenmönster med de olika halterna från dataunderlaggjordes statistiska analyser med PCA och MFA i Rstudio för Oxundaområdet och Stockholmsområdet,och den statistiska analysen PMF i EPA PMF 5.0 samt en undersökning av gradienter för PCB iOxundaområdet. Ett av områdena som studeras är kring Oxundasjön, en sjö norr om Upplands Väsby som sedan år2013, efter miljöövervakning, kunnat konstateras vara ett av de mest förorenade områdena när detkommer till PCB i Sverige. Oxundaområdet har sedan dess haft ett aktivt arbete av provtagningar,undersökningar och analyser kring den troliga geografiska källan men även vad det kan tänkas varaför ursprungliga produkter och är därför ett av områdena som undersöks i detta arbete. Närmareundersökningar har visat att källan med största sannolikhet är ett före detta industriområde iUpplands Väsby, så kallade Messingen, men frågetecken finns fortfarande kring när, hur och vilkaprodukter av PCB som använts i detta område. Det andra området som undersökts ärStockholmsområdet (inklusive dess skärgård, Mälaren och närliggande insjöar), där förhöjda halter avPCB framför allt påvisats i områdena närmast Stockholms stad. Resultat visar en tydlig gradient i Oxundaområdet, med höga PCB-halter i olika undersökta matriser(sediment, biota, ytvatten) i Oxundasjön, Marängsån och Rosersbergviken, som gradvis klingar avnedströms i Mälaren. PCB-halterna uppströms Oxundasjön är betydligt lägre och en tydlig ökning avhalterna syns i Väsbyån i höjd med Upplands Väsby tätort. Därtill visades att EU:s gränsvärden försaluförd fisk överstegs i Oxundasjön, Rosersbergviken och i ett fall även Borgudden. Med hjälp av PCA kunde konstateras de ytliga sedimentproverna främst hade korrelation med delägre kongenerna (PCB28 och PCB52) men även att högklorerade PCB:er (PCB138, PCB153 ochPCB180) hade högre relativ andel i vissa djupare sediment, dessa har dock med stor sannolikhetmycket låga halter. För vattenprover visade platser också nära Messingen (Väsbyån, Ladbrodammen)mer korrelation till högklorerade PCB:er. Platser längre nedströms (Marängsån, Oxundasjön och Rosersbergviken) hade mer korrelation med lägre kongenerna för vatten, likt matrisen biota, somhade en stor majoritetkorrelation med lägre kongenerna. En trolig anledning till detta är läckage frånsediment i Oxundasjöomtrådet. I Stockholmsområdet visade biota (abborre, gädda och strömming) istället en stor blandning av kongenerna, men alla platser visade korrelation högklorerade PCB:ermedan främst platser i centrala Stockholm, innerskärgård och enstaka insjöar visade flerakorrelationer till lägre kongener. För sediment visades främst korrelation med lägre kongener i Stockholmsområdet. PMF (positiv matrisfaktorisering) användes för att närmare se korrelationer med matriserna vattenoch sediment i Oxundaområdet till sju kongensammansättningar av Aroclor. För vatten visades starkkorrelation till Aroclor 1242 (och 1016) medan flertalet sediment (uppströms och i Oxundasjön)visade störst korrelation till Aroclor1260. Aroclor1242 och 1016 är de vanligaste Aroclor (64% av allproduktion av Aroclor) medan Aroclor1260 i tidigare har setts vara en av den mest persistentaAroclor i naturen, vilket kan vara förklaring till dessa resultat i Oxundaområdet. Vidare efterforskningar behöver göras för att säkerhetsställa vilka produkter som utgör källor till PCB-kontamineringen av Oxundaområdet, med fler produkter att jämföra med samt med fler kongenerän indikatorkongenerna, framför allt i vidare studier med PMF. För Stockholmsområdet behövs flerstudier där områdena delas upp, och jämföra potentiella geografiska källor till olika kongenmönster.För bättre förståelse av PCB och dess kongenmönster hade PMF för båda områdena varit lämpligmed ett större kongenuppsättning, speciellt för biota som är en av de mesta komplexa matriserna förföroreningar på grund olika faktorer av den här typen av analyser.
|
17 |
Implantação de boas práticas de gerenciamento de serviços de TI: um estudo de caso na Universidade Federal do Vale do São Francisco - UNI-VASFAraújo, Anderson Igor Ferreira 13 June 2016 (has links)
Submitted by Tatiana Lima (tatianasl@ufba.br) on 2017-02-07T18:17:08Z
No. of bitstreams: 1
Araújo, Anderson Igor Ferreira.pdf: 2868755 bytes, checksum: 2f1862dd8b570e138322fe8915aff0ed (MD5) / Approved for entry into archive by Tatiana Lima (tatianasl@ufba.br) on 2017-02-07T18:28:18Z (GMT) No. of bitstreams: 1
Araújo, Anderson Igor Ferreira.pdf: 2868755 bytes, checksum: 2f1862dd8b570e138322fe8915aff0ed (MD5) / Made available in DSpace on 2017-02-07T18:28:18Z (GMT). No. of bitstreams: 1
Araújo, Anderson Igor Ferreira.pdf: 2868755 bytes, checksum: 2f1862dd8b570e138322fe8915aff0ed (MD5) / Verifica-se, cada vez mais, a dependência das organizações públicas em relação aos serviços de Tecnologia da Informação para satisfazer seus objetivos corporativos e atender às necessi-dades estratégicas. Desta forma, o presente estudo foi motivado pela necessidade da Secreta-ria de Tecnologia da Informação da Universidade Federal do Vale do São Francisco de pro-mover o uso adequado dos recursos de Tecnologia da Informação e a melhoria da qualidade dos serviços de Tecnologia da Informação entregues ao seu público alvo por meio de proces-sos de gestão estruturados. Objetivou-se, portanto, avaliar os níveis de maturidade dos proces-sos de gestão de serviços de Tecnologia da Informação dessa universidade e propor interven-ções de modo que as boas práticas do ITIL pudessem ser implantadas. Tratou-se de uma pes-quisa qualitativa de natureza exploratória, na qual elegeu-se o método de estudo de caso. Fo-ram recolhidas informações por meio de pesquisa documental, questionários e observações visando à triangulação dos dados. A metodologia utilizada teve como base a biblioteca ITIL, a partir da qual foram selecionados cinco processos: Gerenciamento de Configuração e de Ati-vo de Serviço; Gerenciamento de Mudança; Gerenciamento de Liberação e Implantação; Ge-renciamento de Incidente e Gerenciamento de Problema, os quais se submeteram ao Modelo de Maturidade PMF. Os cinco processos avaliados foram qualificados no estágio Inicial ou Ad Hoc de maturidade, onde o processo é reconhecido, contudo existe pouca ou nenhuma atividade dentro da sua finalidade. Além disso, não é beneficiado com alocação de recursos nem orçamento. Desta forma, foi possível identificar problemas e/ou oportunidades de melho-rias. Por fim, foi elaborado um plano de ação no intuito de elevar o nível de maturidade desses processos. / There is, increasingly, dependence of public organizations in relation to Information Technology services to satisfy their corporate aims and strategic needs. Therefore, this study was motivated by necessity of Information Technology Secretariat of the Universidade Feder-al do Vale do São Francisco to promote the appropriate use of information technology re-sources and improving quality of information technology services provided to its public through structured management processes. The objective is, measure the maturity level of information technology service management processes of this university and propose inter-ventions to apply ITIL practices. It was a qualitative research of exploratory nature, where has chosen the method of case study. Information was collected through research, questionnaires and observations aimed data triangulation. The methodology used was based on ITIL library, where it was selected five processes: Service Asset and Configuration Management; Change Management; Release and Deployment Management; Incident Management and Problem Management, which they underwent to PMF Maturity Model. The five cases were qualified in the initial stage of maturity, where the process is recognized, however there is a little or nor activity within its purpose. Moreover, it is not benefited from allocating resources or budget. Thus, it was possible to identify problems and / or opportunities for improvement. Finally, it designed a action plan in order to raise the level of maturity of these processes.
|
18 |
Caractérisation expérimentale et statistique des sources de Composés Organiques Volatils (COV) en région Île-de-France / Experimental and statistical characterization of Volatile Organic Compounds (VOC) within the Île-de-France regionBaudic, Alexia 09 December 2016 (has links)
Les composés organiques volatils (COV) jouent un rôle majeur au sein du système atmosphérique puisqu’ils interviennent en tant que précurseurs d’ozone troposphérique et d’aérosols organiques secondaires (composés aux divers impacts sanitaires et climatiques) ; d’où le réel besoin de mieux les caractériser. A ce jour, de fortes incertitudes demeurent quant à leur nature, leur quantification et la contribution de leurs sources d’émissions respectives.Cette thèse propose, au travers d’expérimentations de laboratoire et de terrain, une caractérisation exhaustive des COV et de leurs principales sources d’émissions en région Île-de-France. Les méthodes mises en place dans ce travail de thèse reposent sur la détermination de profils de spéciation caractéristiques du trafic routier, du chauffage au bois et du gaz naturel à partir d’investigations en champ proche (en tunnel, en cheminée et à partir d’un conduit de gaz domestique). Ces différents profils de source ont été utilisés comme empreinte chimique de référence pour l’identification des principales sources d’émissions de COV, dont les contributions respectives ont été estimées à l’aide du modèle source-récepteur Positive Matrix Factorization (PMF), appliqué sur une année d’acquisition de mesures COV (HCNM+COVO) à Paris. Ce travail de thèse a ainsi permis, pour la première fois, d’étudier la variabilité saisonnière des COV et de leurs sources majeures. Les émissions liées au trafic routier ont été révélées comme la principale source de COV d’origine locale/régionale à Paris (contribuant à ¼ des émissions totales à l’échelle annuelle). L’impact prépondérant du chauffage au bois en hiver (50 % de la masse totale COV mesurée) a également été mis en évidence. Les résultats de cette étude de répartition de sources ont été confrontés à l’inventaire des émissions d’Airparif. Nous avons souligné un bon accord entre nos observations et l’inventaire pour les sources liées au trafic automobile et au chauffage au bois.Cette évaluation indépendante des inventaires est essentielle puisque ces derniers sont aujourd’hui utilisés comme données d’entrée au sein des modèles de prévision de qualité de l’air. / Volatile organic compounds (VOCs) play a key role within the atmospheric system acting as precursors of ground-level ozone and secondary organic aerosols (causing health and climatic impacts); hence the growing interest of better characterizing them. Significant uncertainties are still associated with compounds speciation, quantification and respective contributions from the different emission sources.This thesis proposes, through several laboratory and intensive field campaigns, a detailed characterization of VOCs and their main emissions sources within the Île-de-France region. We used methods based on the determination of speciation profiles indicative of road traffic, wood burning and natural gas sources obtained from near-field investigations (inside a tunnel, at a fireplace and from a domestic gas flue). These different source profiles were used as chemical fingerprints for the identification of the main VOC emission sources, which respective contributions were estimated using the Positive Matrix Factorization (PMF) source-receptor model applied to one-year VOCs (including NMHC+OVOC) measurements in Paris. This thesis allowed, for the first time, to evaluate the seasonal variability of VOCs and their main emission sources. Road traffic-related emissions are major VOC local/regional sources in Paris (contributing to a quarter of total annual emissions). The important impact of wood burning in winter (50 % of the VOC total mass) was observed. Results obtained from this approach were compared with the regional emissions inventory provided by the air quality monitoring network Airparif. Finally, a good agreement was found between our observations and the inventory for road traffic and wood burning-related sources.This independent assessment of inventories is of great interest because they are currently used as input data within air quality prediction models.
|
19 |
Sources des aérosols en milieu urbain : cas de la ville de Paris / Aerosol composition and source apportionment in urban areas : case of Paris City Metropolitan AreaAbidi, Ehgere 18 December 2013 (has links)
La connaissance des sources des particules dans le milieu ambiant est devenue une préoccupation majeure depuis que leur impact sur la santé est avéré. Ainsi, une connaissance détaillée de la nature des fines particules (PM) et de leurs sources, devient nécessaire pour quantifier l’importance des émissions sur la masse totale en PM. Dans ce contexte, l’objectif de ce travail est de mieux connaître la composition chimique et les sources de l’aérosol organique. Les travaux réalisés s’intègrent dans le cadre du projet MEGAPOLI. Deux campagnes ont été conduites en région parisienne en été et en hiver sur deux sites urbain (LHVP) et suburbain (SIRTA). Une caractérisation chimique des PM2.5 a été effectuée. La contribution des sources primaires des PM2.5 fut calculée par modélisation CMB et les résultats furent par la suite intercomparés à ceux obtenus par les approches AMS/PMF et radiocarbone 14C. L’analyse CMB montra qu’en hiver, les principales sources contributrices sont les sources primaires, dominées par les émissions véhiculaires et la combustion de la biomasse. En été, les concentrations de PM2.5 sont gouvernées par les espèces secondaires. D’après l’approche basée sur les marqueurs organiques secondaires, le SOA biogénique traditionnel contribue faiblement à la masse de PM2.5. La comparaison des deux approches CMB et AMS-PMF a montré qu’en hiver, les différences ont été observées pour les deux sources majeures d’aérosol organique : combustion de biomasse et source véhiculaire. En été, les différences obtenues sont moins marquées. Les comparaisons des résultats de modélisation CMB avec les mesures de 14C, approche totalement indépendante, montrèrent un bon accord. / Knowing the sources of airborne fine particulate matter in ambient area became a major concern since their adverse effects on health were. Then, knowing in detail the nature and the sources of the fine particles (PM) is necessary to quantify the relative importance of the emissions on the total PM concentration. In this context, the main objective is to better know the chemical composition and the sources of the organic aerosol. This works is integrated within the MEGAPOLI framework. Two intensive campaigns were led in Paris region in summer and in winter at an urban (LHVP) and a suburban (SIRTA) sites. During the both sampling campaigns, a complete PM2.5 chemical characterization was made. The contributions of the PM2.5 primary sources were calculated by CMB modelling and the results were intercompared with those obtained by the AMS/PMF and the radiocarbon 14C approaches. The CMB analysis showed that in winter, the main contributing sources were primary, dominated by vehicular exhaust and biomass burning. In summer, the PM2.5 ambient concentrations were mainly governed by secondary species. According to the approach based on the secondary organic markers, the traditional biogenic SOA contribution to the PM2.5 mass was. The both CMB and AMS-PMF approaches comparison showed that in winter, the differences were particularly observed for both major organic aerosol sources: biomass burning and vehicular exhaust. In summer, the differences between both approaches were less visible. The comparisons of the CMB modeling approach results with the radiocarbon 14C measurements, a totally independent approach, show a very good agreement between both approaches
|
20 |
”Learning by doing är bäst av allt egentligen” : Nyare säkerhetsstandarder och kunskapsinhämtninginom trådlösa nätverkMulshine, Tim, Berkemar, Linus January 2023 (has links)
Då data som transporteras över trådlösa nätverk sänds genom luften i form av radiovågor är det viktigt att säkra upp nätverkskommunikationen med nya, erkändasäkerhetsstandarder. Däremot är användningsgraden av nyare säkerhetsstandarder inom Wi-Fi, specifikt WPA3 och PMF, låg. Samtidigt finns ett behov att öka förståelsen för relevanta metoder för kunskapsinhämtning. Syftet med studien är att ge rekommendationer för hur små och medelstora företag kan öka säkerheten i trådlösa nätverk. Studien identifierar orsaker till den låga användningsgraden av nyare säkerhetsstandarder i trådlösa nätverk och även hur nätverksadministratörer håller sig uppdaterade om standarderna. En kvalitativ ansats valdes för att besvara studiens syfte, vilket genomfördes med hjälp av 23 semi-strukturerade intervjuer med nätverksadministratörer i Sverige. Studiens resultat visar på ett tydligt tema där klientbasen i nätverken är huvudanledningen till avvaktandet med att implementera nyare säkerhetsstandarder, där kompabilitet upplevs som ett problem samtidigt som det råder okunskap om standarderna. Bland respondenterna anses metoden praktiskt laborerande vara mest effektiv för kunskapsinhämtning och fortbildning, ofta i samband med läsande av teori för att bilda en grundläggande förståelse. Studien landar i rekommendationer om de nyare säkerhetsstandarderna och kunskapsinhämtning riktade mot nätverksadministratörer, företag och även myndigheter och organisationer som bidrar med riktlinjer om trådlösa nätverk. / As data transmitted over wireless networks is sent through air, in the form of radio waves, it is important to secure network communication with new, recognized security standards. However, the adoption rate of newer security standards in Wi-Fi, specifically WPA3 and PMF, is low. At the same time, there is a need to increase understanding of relevant methods for knowledge acquisition. This study’s purpose is to provide recommendations on how small and medium-sized enterprises can increase the security of wireless networks. The study identifies reasons for the low adoption rate of newer security standards in wireless networks and how network administrators stay updated on the standards. A qualitative approach was chosen to address the study's purpose, which was conducted through 23 semi-structured interviews with network administrators in Sweden. The study's results reveal a clear theme where the client base in the networks is the main reason for reservations to implement newer security standards, with compatibility being perceived as a problem alongside a lack of knowledge about the standards. Among the respondents, practical experimentation is considered the most effective method for knowledge acquisition and continuous education, often combined with reading of theory to form a fundamental understanding. The study concludes with recommendations on the newer security standards and knowledge acquisition targeted towards network administrators, companies, as well as authorities and organizations that provide guidelines on wireless networks.
|
Page generated in 0.0419 seconds