1,220 research outputs found

    A Comparative Study of Coq and HOL

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    This paper illustrates the differences between the style of theory mechanisation of Coq and of HOL. This comparative study is based on the mechanisation of fragments of the theory of computation in these systems. Examples from these implementations are given to support some of the arguments discussed in this paper. The mechanisms for specifying definitions and for theorem proving are discussed separately, building in parallel two pictures of the different approaches of mechanisation given by these systems

    Construction and Application of an LP Farm Model with an Integrated Life Cycle Assessment for the Determination of Sustainable Milk Production Systems

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    The increasingly stringent conditions underlying Swiss dairy production demand sustainable milk production systems that are economically optimized but also meet the ecological requirements of society. To determine such systems, a comparative-static LP model was constructed at farm level. Realistic production systems are reproduced in the model by means of binary variables. An Life Cycle Assessment (LCA) was integrated into the model to determine the environmental impacts of the farm. To this effect, the internal farm influences on production are illustrated in detail. An initial application of the model, in which a comparison of different income-optimized production systems was carried out, revealed some goal conflicts between economics and ecology. Systems involving full-time grazing achieved the best results in both aspects.Life Cycle Assessment (LCA), LP-model, dairy production, production system, Livestock Production/Industries, C61, Q12, Q51,

    Performance Analysis and Capacity Planning of Multi-stage Stochastic Order Fulfilment Systems with Levelled Order Release and Order Deadlines

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    Kundenorientierte Auftragsbearbeitungsprozesse in Logistik- und Produktionssystemen sind heutzutage mit einem kontinuierlich steigenden Auftragsvolumen zunehmend kleinvolumiger AuftrĂ€ge, hohen Kundenanforderungen hinsichtlich kurzfristiger und individueller Lieferfristen und einer stark stochastisch schwankenden Kundennachfrage konfrontiert. Um trotz der volatilen Kundennachfrage eine effiziente Auftragsbearbeitung und die Einhaltung der kundenindividuellen Lieferfristen gewĂ€hrleisten zu können, muss die Arbeitslast kundenorientierter Auftragsbearbeitungsprozesse auf geeignete Weise geglĂ€ttet werden. Hopp und Spearman (2004) unterscheiden zur Kompensation von Schwankungen in Produktionssystemen zwischen den Dimensionen Bestand, Zeit und KapazitĂ€t. Diese stellen auch einen guten Ausgangspunkt fĂŒr die Entwicklung von GlĂ€ttungskonzepten fĂŒr stochastische, kundenorientierte Bearbeitungsprozesse dar. In dieser Arbeit werden die Potentiale der Dimensionen Zeit und KapazitĂ€t in der Strategie der nivellierten Auftragseinlastung zusammengefĂŒhrt, um die Arbeitslast mehrstufiger, stochastischer Auftragsbearbeitungsprozesse mit kundenindividuellen FĂ€lligkeitsfristen auf taktischer Ebene zeitlich zu glĂ€tten. Ziel dieser Arbeit ist (1) die Entwicklung eines GlĂ€ttungskonzeptes, der so genannten Strategie der nivellierten Auftragseinlastung, (2) die Entwicklung eines zeitdiskreten analytischen Modells zur Leistungsanalyse und (3) die Entwicklung eines Algorithmus zur KapazitĂ€tsplanung unter GewĂ€hrleistung bestimmter Leistungsanforderungen fĂŒr mehrstufige, stochastische Auftragsbearbeitungsprozesse mit nivellierter Auftragseinlastung und kundenindividuellen FĂ€lligkeitsfristen. Die Strategie der nivellierten Auftragseinlastung zeichnet sich durch die Bereitstellung zeitlich konstanter KapazitĂ€ten fĂŒr die Auftragsbearbeitung und eine Auftragsbearbeitung gemĂ€ĂŸ aufsteigender FĂ€lligkeitsfristen aus. Auf diese Weise wird der zeitliche Spielraum jedes Auftrags zwischen dessen Auftragseingang und dessen FĂ€lligkeitsfrist systematisch zur Kompensation der stochastischen Nachfrageschwankungen genutzt. Die verbleibende VariabilitĂ€t wird in AbhĂ€ngigkeit der Leistungsanforderungen der Kunden durch die Höhe der bereitgestellten KapazitĂ€t kompensiert. Das analytische Modell zur Leistungsanalyse mehrstufiger, stochastischer Auftragsbearbeitungsprozesse mit nivellierter Auftragseinlastung und kundenindividuellen FĂ€lligkeitsfristen bildet die Auftragsbearbeitung als zeitdiskrete Markov-Kette ab und berechnet verschiedene stochastische und deterministische LeistungskenngrĂ¶ĂŸen auf Basis deren asymptotischer Zustandsverteilung. Diese KenngrĂ¶ĂŸen, wie beispielsweise Durchsatz, Servicegrad, Auslastung, Anzahl Lost Sales sowie Zeitpuffer und RĂŒckstandsdauer eines Auftrags, ermöglichen eine umfassende und exakte Leistungsanalyse von mehrstufigen, stochastischen Auftragsbearbeitungsprozessen mit nivellierter Auftragseinlastung und kundenindividuellen FĂ€lligkeitsfristen. Der Zusammenhang zwischen der bereitgestellten KapazitĂ€t und der damit erreichbaren LeistungsfĂ€higkeit kann nicht explizit durch eine mathematische Gleichung beschrieben werden, sondern ist implizit durch das analytische Modell gegeben. Daher ist das Entscheidungsproblem der KapazitĂ€tsplanung unter GewĂ€hrleistung bestimmter Leistungsanforderungen ein Blackbox-Optimierungsproblem. Die problemspezifischen Konfigurationen der Blackbox-Optimierungsalgorithmen Mesh Adaptive Direct Search und Surrogate Optimisation Integer ermöglichen eine zielgerichtete Bestimmung des minimalen prozessspezifischen KapazitĂ€tsbedarfs, der zur GewĂ€hrleistung der Leistungsanforderungen der Kunden bereitgestellt werden muss. Diese werden anhand einer oder mehrerer LeistungskenngrĂ¶ĂŸen des Auftragsbearbeitungsprozesses spezifiziert. Numerische Untersuchungen zur Beurteilung der LeistungsfĂ€higkeit der Strategie der nivellierten Auftragseinlastung zeigen, dass in Systemen mit einer Auslastung grĂ¶ĂŸer als 0,6 durch den Einsatz der Strategie der nivellierten Auftragseinlastung ein deutlich höherer α\alpha- und ÎČ\beta-Servicegrad erreicht werden kann als mit First come first serve. Außerdem ist der KapazitĂ€tsbedarf zur GewĂ€hrleistung eines bestimmten α\alpha-Servicegrads bei Einsatz der Strategie der nivellierten Auftragseinlastung höchstens so hoch wie bei Einsatz von First come first serve

    Design and Implementation of a NoSQL-concept for an international and multicentral clinical database

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    Tinnitus is a very complex symptom that has many subtypes, which all require different treatment methods. The Tinnitus Database collects the data of tinnitus patients in centers all over the world, with the aim of helping doctors in determining the correct subtype of tinnitus the patient suffers and determining the best treatment method. This is done by providing the relevant information, out of the huge amount of data that is stored in the database, to the doctor. The current database is based on MySQL and it has two main problems. First, the application needs many joins to provide the relevant information that is distributed among different tables. This causes a long response time in some cases. The other problem is the data validation that is pretty important in medical processes, as if it is violated the health of people could be affected. For example, there only exist some possible treatment methods, so it should not be possible to assign another treatment method to a patient. Currently, this has to be ensured with additional methods in the application and additional tables in the database. This thesis examines different NoSQL technologies, if they could solve these two problems and what other advantages or disadvantages they have compared to relational databases. The purpose of this thesis is then to find the best fitting database technology for the system

    Breeding during a Predation Regime Shift : Behavioural and physiological responses of female common eiders facing the recovery of their native predator

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    Predation is a key selective force driving prey trait evolution. Yet, the extent to which predator-consumptive and predation risk effects shape phenotypes is still poorly understood. Since predation risk increases the cost of current reproduction, long-lived prey are predicted to prioritize survival and future reproduction by reducing reproductive investment under high predation risk (e.g., through changes in life-history, behaviour, physiology or morphology). However, the relative roles played by adaptive plastic responses (i.e., withinindividual phenotypic variation) and selective processes (i.e., among-individual phenotypic variation) in allowing populations and individuals to persist under fluctuating predation threat in the wild have been overlooked. In my thesis, I shed light on these knowledge gaps by evaluating the responses of a sea duck species, the common eider Somateria mollissima, to fluctuating predation risk from their native predator, the white-tailed eagle Haliaeetus albicilla. I focused on adjustments of behavioural and physiological traits to the recovery of white-tailed eagles in southwestern Finland. As a longlived species characterised by energetically-costly fasting during incubation and frequent intermittent breeding, common eiders are ideal for studying the life-history trade-off between reproduction and survival. I relied on a longterm individual-based monitoring of breeding females (> 2500 breeding attempts from > 1000 individuals in 2008-2022) to explore variations in risktaking behaviour (measured by flight initiation distance) and physiological proxies of energy allocation (baseline corticosterone levels) and parental effort (baseline prolactin levels) in response to temporally and spatially variable predation risk. The longitudinal data collection was not restricted to the focal variables, but also integrated a monitoring of female characteristics (e.g., age, body condition and clutch size) and parameters such as nesting microhabitat and fine- and large-scale predation risk indices, allowing a good understanding of concurrent changes occurring in the population. First, in agreement with the prediction that long-lived prey should reduce parental investment under elevated predation threat, I found that increasing predation threat was associated with longer flight initiation distances (i.e., reduced risk-taking) over breeding attempts. Importantly, this response was explained by a plastic adjustment of flight initiation distance to the risk of predation on breeding females, but also by the selective disappearance of risktaking phenotypes from islands characterised by high nest predation risk. Supporting the latter notion, I showed that risk-taking strategies affected fitness (including survival, breeding propensity and hatching success), especially under elevated predation risk. My results thus provide among the first evidence that the target of predation (adults or offspring) determines the mechanisms driving adjustment of risk-taking propensity to perceived predation risk. In risky environments, females were also more likely to rely on prior experience with a threat to dampen their flight response when repeatedly confronted with a harmless stimulus (here, a human approach over consecutive days). Such short-term habituation to non-life-threatening stimuli is likely adaptive and could limit the reproductive costs of an overreaction to benign stimuli. Second, I found that baseline corticosterone levels were positively associated with reproductive investment. In addition, baseline corticosterone levels were downregulated when incubating under high predator activity, again reflecting decreased energetic reproductive investment under threat of predation. Additionally, this physiological adjustment was habitat-dependent, as females downregulated baseline corticosterone levels under higher predation risk on themselves on open islands (associated with lower adult survival) but not on forested islands where nests are visually concealed from predators. Last, while I predicted that incubating females would display lower baseline prolactin levels – mediating reduced parental effort – under high predation threat, this prediction was not directly supported by my results. However, elevated baseline prolactin levels were still found to be indirectly related to predation pressure. Indeed, elevated prolactin levels seemed to promote hatching success in years characterised by elevated predation pressure. Overall, high prolactin levels favoured hatching success under constraining extrinsic (e.g., poor climatic conditions) or intrinsic conditions (e.g., when incubating a large clutch). Thus, the results drawn from my thesis provide valuable insight into the short- and long-term responses of prey individuals and populations to a changing predation regime. Interestingly, most of the observed responses seemed to be driven by within-individual adjustments of behaviour or physiology to perceived predation threat, supporting the idea that predation risk effect may be more important in explaining prey trait evolution than predatorconsumptive effects. However, even though longitudinal studies carried out in the wild have the advantage of encompassing the complexity of natural processes by integrating concomitant changes in intrinsic or extrinsic factors, these studies remain correlational, and further experimental work is needed to assess the causal links between predation risk and prey responses. Nevertheless, my results have far-reaching implications for conservation, by improving the knowledge on seabird responses to fluctuating predation risk from a native avian predator.Predationen driver evolutionen av bytesdjurs egenskaper, men de direkta och indirekta predationseffekternas roll Ă€r omdebatterad. Eftersom predationsrisken ökar kostnaden för nuvarande reproduktion, förvĂ€ntas lĂ„nglivade bytesdjur prioritera överlevnad och framtida reproduktion genom minskad reproduktiv investering under hög predationsrisk (via förĂ€ndringar i livshistoria, beteende, fysiologi eller morfologi). Dock Ă€r den relativa betydelsen av adaptiva plastiska reaktioner (inom-individuell fenotypisk variation) och selektion (fenotypisk variation mellan individer) föga kĂ€nda vid anpassningen till varierande predationstryck. Jag fyller dessa kunskapsluckor genom att utvĂ€rdera hurdana beteendemĂ€ssiga och fysiologiska responser ejdern Somateria mollissima uppvisar pĂ„ fluktuerande predationsrisk frĂ„n sin naturliga predator, havsörnen Haliaeetus albicilla, vars population snabbt Ă„terhĂ€mtat sig i sydvĂ€stra Finland. Eftersom ejdern Ă€r lĂ„nglivad, genomgĂ„r en energimĂ€ssigt pĂ„frestande ruvning och regelbundet avstĂ„r frĂ„n hĂ€ckning, Ă€r den idealisk för att studera livshistorieavvĂ€gningen mellan reproduktion och överlevnad. Min avhandling bygger pĂ„ en individuell lĂ„ngtidsuppföljning av hĂ€ckande Ă„dor (> 2500 hĂ€ckningsförsök; > 1000 individer; t2008-2022) och m.h.a. dessa data undersökte jag hur risktagningsbenĂ€genheten (flyktavstĂ„nd frĂ„n boet), energiallokeringen (grundnivĂ„n av kortikosteron) och investeringen i omvĂ„rdnad av avkomman (grundnivĂ„n av prolaktin) beror pĂ„ temporĂ€rt och rumsligt varierande predationsrisk. Data omfattade Ă€ven andra individuella egenskaper (t.ex. Ă„lder, kroppskondition och kullstorlek), hĂ€ckningsmikrohabitat och fin- och storskaliga predationsriskindex, för att kunna följa upp andra förĂ€ndringar som skett i populationen. LĂ„nglivade bytesdjur förvĂ€ntas minska investeringen i reproduktion under förhöjt predationshot, och i enlighet med detta fann jag att ett ökat predationshot var förknippat med lĂ€ngre flyktavstĂ„nd frĂ„n boet (minskat risktagande) mellan upprepade hĂ€ckningsförsök. Detta förklarades av en plastisk justering av flyktavstĂ„ndet till predationsrisk riktad mot hĂ€ckaren sjĂ€lv, men ocksĂ„ av ett selektivt bortfall av risktagande fenotyper pĂ„ öar med hög bopredationsrisk. Sammantaget pĂ„verkade risktagningsstrategierna fitness (överlevnad, hĂ€ckningsbenĂ€genhet och hĂ€ckningsutfall), i synnerhet dĂ„ predationsrisken var hög. Dessa resultat utgör ett av de första bevisen pĂ„ att mĂ„let för predation (vuxna individen eller avkomman) formar de mekanismer som driver anpassningen av risktagningsbenĂ€genhet till predationsrisk. I farliga miljöer var Ă„dorna ocksĂ„ mer benĂ€gna att förlita sig pĂ„ tidigare erfarenhet av predationshot, vilket dĂ€mpade flyktresponsen under upprepade konfrontationer med ett ofarligt stimulus (mĂ€nniska) under samma hĂ€ckning. Kortvarig habituering till icke-livshotande stimuli Ă€r adaptivt ifall det minskar de reproduktiva kostnaderna för att överreagera pĂ„ godartade stimuli. GrundnivĂ„n av kortikosteron var positivt associerad med reproduktiv investering. KortikosteronnivĂ„erna minskade dĂ„ rovdjursaktiviteten var hög, vilket Ă„terspeglar minskad energetisk reproduktiv investering under predationshot. Denna fysiologiska justering berodde pĂ„ livsmiljön – Ă„dorna hade en lĂ€gre kortikosteronnivĂ„ dĂ„ de utsattes för ett predationshot pĂ„ öppna öar (lĂ€gre vuxenöverlevnad) – men inte pĂ„ skogsklĂ€dda öar, som erbjuder ett bĂ€ttre skydd frĂ„n rovdjur. Jag förutspĂ„dde att ruvande Ă„dor skulle uppvisa lĂ€gre grundnivĂ„er av prolaktin under högt predationshot – eftersom detta kunde styra en minskad satsning pĂ„ omvĂ„rdnad av avkomman – en prediktion som inte stöddes av mina resultat. ProlaktinnivĂ„erna visade sig dock vara indirekt relaterad till predationstrycket, eftersom en hög nivĂ„ frĂ€mjade klĂ€ckningsframgĂ„ngen dĂ„ predationstrycket var högt. Sammantaget gynnade höga prolaktinnivĂ„er klĂ€ckningsframgĂ„ngen under krĂ€vande yttre (dĂ„liga klimatförhĂ„llanden) eller inre förhĂ„llanden (stor kull). Mina resultat belyser hur bytesindivider och -populationer pĂ„ kort och lĂ„ng sikt reagerar pĂ„ en förĂ€ndrad predationsregim. De flesta responser berodde pĂ„ inom-individuella anpassningar av beteende eller fysiologi till predationshot; alltsĂ„ kan predationsrisken vara viktigare för att förklara evolutionen av bytesdjurs egenskaper Ă€n den direkta dödligheten. Trots att longitudinella studier tar hĂ€nsyn till komplexiteten i naturliga processer genom att integrera förĂ€ndringar i inre eller yttre faktorer, Ă€r de ofta korrelativa. DĂ€rför behövs experiment för att identifiera kausaliteten mellan predationsrisk och bytesdjurens responser. Det oaktat Ă€r mina resultat bevarandebiologiskt vĂ€rdefulla, genom att de förbĂ€ttrar kunskapen om sjöfĂ„glars responser pĂ„ fluktuerande predationsrisk frĂ„n en naturligt förekommande fĂ„gelpredator.La prĂ©dation agit comme une force de sĂ©lection majeure faisant Ă©voluer les phĂ©notypes des proies. Cependant, la mesure dans laquelle la consommation directe de proies par les prĂ©dateurs et le risque de prĂ©dation façonnent ces traits est encore mĂ©connue. Etant donnĂ© que le risque de prĂ©dation augmente le coĂ»t de la reproduction, les espĂšces longĂ©vives devraient prioriser leur survie et leur reproduction future en rĂ©duisant leur investissement reproducteur lorsque le risque de prĂ©dation est Ă©levĂ© (par exemple en modifiant leurs traits d’histoires de vie, comportement, physiologie ou morphologie). Cependant, le rĂŽle de la plasticitĂ© et de la sĂ©lection dans la capacitĂ© des populations et des individus Ă  faire face Ă  un risque de prĂ©dation fluctuant a Ă©tĂ© peu Ă©tudiĂ©e dans un contexte naturel. Dans ma thĂšse, j’ai mis ces mĂ©canismes en lumiĂšre en Ă©valuant les rĂ©ponses d’un oiseau marin, l’eider Ă  duvet Somateria mollissima, face au retour de son prĂ©dateur, le pygargue Ă  queue blanche Haliaeetus albicilla. Cette espĂšce est idĂ©ale pour Ă©tudier les compromis entre reproduction et survie, notamment en raison de sa longue durĂ©e de vie et de sa capacitĂ© Ă  jeĂ»ner durant l’incubation et Ă  se reproduire de maniĂšre intermittente. A travers un suivi Ă  long terme (2008-2022) j’ai explorĂ© les modifications de comportement de prise de risque (mesurĂ©e Ă  travers la distance de fuite) et d’indicateurs physiologiques d’allocation Ă©nergĂ©tique (Ă©valuĂ©e via les niveaux basaux de corticostĂ©rone) et d’effort parental (mesurĂ© via les niveaux basaux de prolactine) en rĂ©ponse Ă  une variation spatio-temporelle de la prĂ©dation. Ce jeu de donnĂ©es n’est pas restreint au suivi des variables d’intĂ©rĂȘt mais inclut Ă©galement les caractĂ©ristiques des individus (par exemple leur Ăąge, condition corporelle ou taille de ponte), de leur nid, ou le risque de prĂ©dation Ă  fine et large Ă©chelles, permettant de comprendre les divers changements se produisant simultanĂ©ment dans la population. Tout d’abord, en accord avec la prĂ©diction selon laquelle les proies longĂ©vives devraient rĂ©duire leur investissement parental lorsque la prĂ©dation est forte, j’ai montrĂ© qu’une augmentation de la prĂ©dation Ă©tait associĂ©e Ă  un allongement de la distance de fuite, indiquant une rĂ©duction de la prise de risque. Cette rĂ©ponse est liĂ©e Ă  une modification plastique (intraindividuelle) de la distance de fuite au risque de prĂ©dation des adultes, Ă  laquelle s’ajoute une disparition sĂ©lective (inter-individuelle) des phĂ©notypes associĂ©s Ă  une forte prise de risque sur les Ăźles oĂč la prĂ©dation des nids est forte. En accord avec cette idĂ©e, j’ai mis en Ă©vidence un lien entre stratĂ©gie de prises de risque traits dĂ©mographiques (survie, probabilitĂ© de se reproduire et succĂšs Ă  l’éclosion), en particulier lorsque la prĂ©dation est Ă©levĂ©e. Mes rĂ©sultats sont parmi les premiers Ă  montrer que les mĂ©canismes (plasticitĂ© ou sĂ©lection) façonnant les ajustements de prise de risque des individus dĂ©pendent de la cible des prĂ©dateurs (parents ou progĂ©niture). A l’échelle intra-annuelle, les femelles nichant sur des Ăźles oĂč la predation est forte Ă©taient, au contraire, plus susceptibles de rĂ©duire leur distance de fuite lorsqu’elles Ă©taient confrontĂ©es de maniĂšre rĂ©pĂ©tĂ©e Ă  une tentative de prĂ©dation (une approche humaine rĂ©pĂ©tĂ©e pendant plusieurs jours consĂ©cutifs). Cette habituation Ă  court terme pourrait limiter les coĂ»ts reproductifs associĂ©s Ă  l’expression d’une surrĂ©action face Ă  des stimuli stressants mais bĂ©nins. De plus, j’ai montrĂ© que les niveaux basaux de corticostĂ©rone Ă©taient reliĂ©s positivement Ă  l’investissement reproducteur. Les femelles incubant sous fort risque de prĂ©dation prĂ©sentaient des niveaux plus faibles, reflĂ©tant de nouveau une rĂ©duction de l’investissement Ă©nergĂ©tique dans la reproduction. Cet ajustement physiologique dĂ©pendait de l'habitat, les femelles rĂ©duisant leurs niveaux basaux de corticostĂ©rone en cas de risque Ă©levĂ© de prĂ©dation sur ellesmĂȘmes sur les Ăźles ouvertes (associĂ©es Ă  une survie adulte plus faible), mais pas sur les Ăźles boisĂ©es oĂč les nids sont dissimulĂ©s sous la vĂ©gĂ©tation. Enfin, alors que j'avais prĂ©dit que les femelles prĂ©senteraient des niveaux basaux de prolactine plus bas (mĂ©diant une rĂ©duction de l'effort parental) en cas de risque de prĂ©dation Ă©levĂ©, aucune relation directe entre la prolactine et la prĂ©dation n’a Ă©tĂ© mise en Ă©vidence par mes rĂ©sultats. NĂ©anmoins, j’ai montrĂ© l’existence d’une relation indirecte entre les niveaux basaux de prolactine et la prĂ©dation. En effet, maintenir des niveaux basaux Ă©levĂ©es de prolactine pendant l’incubation semble favoriser le succĂšs Ă  l’éclosion lorsque les conditions extrinsĂšques ou intrinsĂšques sont contraignantes. Cela inclut un risque de prĂ©dation Ă©levĂ©, de mauvaises conditions nutritives avant la reproduction, ou encore le fait d’incuber un grand nombre d’oeufs. Les rĂ©sultats de ma thĂšse permettent ainsi de mieux comprendre les rĂ©ponses Ă  court et long terme des proies face Ă  un changement de rĂ©gime de prĂ©dation. Ces rĂ©ponses semblent principalement rĂ©sulter d'ajustements intra-individuels, soutenant l’idĂ©e selon laquelle le risque de prĂ©dation pourrait mieux prĂ©dire les Ă©volutions des phĂ©notypes que la consommation directe des proies par les prĂ©dateurs. Cependant, mĂȘme si les Ă©tudes basĂ©es sur des suivis long-terme en milieu naturel ont l'avantage de prendre en compte la complexitĂ© des processus naturels, elles restent corrĂ©lationnelles, et des travaux expĂ©rimentaux sont maintenant nĂ©cessaires afin d’identifier les liens de cause Ă  effet entre le risque de prĂ©dation et les rĂ©ponses des proies. Mes rĂ©sultats ont nĂ©anmoins des implications pour la conservation, en approfondissant les connaissances sur les rĂ©ponses des oiseaux marins Ă  une prĂ©dation fluctuante de la part d'un prĂ©dateur indigĂšne

    Sand

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    Performance Analysis and Capacity Planning of Multi-stage Stochastic Order Fulfilment Systems with Levelled Order Release and Order Deadlines

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    Order fulfilment systems are forced to manage a volatile customer demand while meeting customer-required short order deadlines. To handle these challenges, we introduce the Strategy of Levelled Order Release (LOR) for workload balancing over time. The contributions of this work are (1) the workload balancing concept LOR, (2) a discrete-time Markov chain for performance analysis, and (3) an algorithm for capacity planning under performance constraints in order fulfilment systems with LOR

    Smart streetlights: a feasibility study

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    The world's cities are growing. The effects of population growth and urbanisation mean that more people are living in cities than ever before, a trend set to continue. This urbanisation poses problems for the future. With a growing population comes more strain on local resources, increased traffic and congestion, and environmental decline, including more pollution, loss of green spaces, and the formation of urban heat islands. Thankfully, many of these stressors can be alleviated with better management and procedures, particularly in the context of road infrastructure. For example, with better traffic data, signalling can be smoothed to reduce congestion, parking can be made easier, and streetlights can be dimmed in real time to match real-world road usage. However, obtaining this information on a citywide scale is prohibitively expensive due to the high costs of labour and materials associated with installing sensor hardware. This study investigated the viability of a streetlight-integrated sensor system to affordably obtain traffic and environmental information. This investigation was conducted in two stages: 1) the development of a hardware prototype, and 2) evaluation of an evolved prototype system. In Stage 1 of the study, the development of the prototype sensor system was conducted over three design iterations. These iterations involved, in iteration 1, the live deployment of the prototype system in an urban setting to select and evaluate sensors for environmental monitoring, and in iterations 2 and 3, deployments on roads with live and controlled traffic to develop and test sensors for remote traffic detection. In the final iteration, which involved controlled passes of over 600 vehicle, 600 pedestrian, and 400 cyclist passes, the developed system that comprised passive-infrared motion detectors, lidar, and thermal sensors, could detect and count traffic from a streetlight-integrated configuration with 99%, 84%, and 70% accuracy, respectively. With the finalised sensor system design, Stage 1 showed that traffic and environmental sensing from a streetlight-integrated configuration was feasible and effective using on-board processing with commercially available and inexpensive components. In Stage 2, financial and social assessments of the developed sensor system were conducted to evaluate its viability and value in a community. An evaluation tool for simulating streetlight installations was created to measure the effects of implementing the smart streetlight system. The evaluation showed that the on-demand traffic-adaptive dimming enabled by the smart streetlight system was able to reduce the electrical and maintenance costs of lighting installations. As a result, a 'smart' LED streetlight system was shown to outperform conventional always-on streetlight configurations in terms of financial value within a period of five to 12 years, depending on the installation's local traffic characteristics. A survey regarding the public acceptance of smart streetlight systems was also conducted and assessed the factors that influenced support of its applications. In particular, the Australia-wide survey investigated applications around road traffic improvement, streetlight dimming, and walkability, and quantified participants' support through willingness-to-pay assessments to enable each application. Community support of smart road applications was generally found to be positive and welcomed, especially in areas with a high dependence on personal road transport, and from participants adversely affected by spill light in their homes. Overall, the findings of this study indicate that our cities, and roads in particular, can and should be made smarter. The technology currently exists and is becoming more affordable to allow communities of all sizes to implement smart streetlight systems for the betterment of city services, resource management, and civilian health and wellbeing. The sooner that these technologies are embraced, the sooner they can be adapted to the specific needs of the community and environment for a more sustainable and innovative future
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