9616 research outputs found
Sort by
Designing the Intermodal Multiperiod Transportation Network of a Logistic Service Provider Company for Container Management
No full textLured by the promise of bigger sales, companies are increasingly looking to raise the volume of international trade. Consequently, the amount of bulk products carried in containers and transported overseas exploded because of the flexibility and reliability of this type of transportation. However, minimizing the logistics costs arising from the container flow management across different terminals has emerged asa major problem that companies and affiliated third-party logistics firms face routinely.
The empty tankcontainer allocation problem occurs in the context of intermodal distribution systems management and transportation operations carried out by logistic service provider companies. This paper considers the time-evolving supply chain system of an international logistic service provider company that transports bulk products loaded in tank containers via road, rail and sea. In such system, unbalanced movements of loaded tank containers forces the company to reposition empty tank containers. The purpose of this paper is to develop a mathematical model that supports tactical decisions for flow management of empty tank containers. The problem involves dispatching empty tank containers of various types to the meet on-time delivery requirements and repositioning the other tank containers to storage facilities, depots and cleaning stations. To this aim, a mixed-integer linear programming (MILP) multiperiod optimization model is developed.
The model is analyzed and developed step by step, and its functionality is demonstrated by conducting experiments on the network from our case study problem, within the boarders of Europe. The case study constitutes three different scenarios of empty tank container allocation. The computational experiments show that the model finds good quality solutions, and demonstrate that cost and modality improvements can be achieved in the network The sensitivity analysis employs a set of data from our case study and randomly selected data to highlight certain features of the model and provide some insights regarding the model’s behavior.Internationell handel ¨okar i takt med f¨oretags str¨avan om att uppn°a h¨ogre f¨ors¨aljningsresultat
genom ¨okade exportvolymer. Transporter mellan kontinenter av containrar lastade med
bulkprodukter har ¨okat avsev¨art p°a grund av den flexibilitet och tillf¨orlitlighet denna typ
av transport erbjuder. Att minimera logistikkostnaderna f¨or transporter mellan olika terminaler
har mynnat ut i ett betydande problem f¨or f¨oretag som erbjuder tredjepartlogistik.
”Tomcontainer allokerings problemet” involverar f¨oretag som erbjuder logistiska tj¨anster
inom intermodala distributionssystem genom att l¨agga ut dessa tj¨anster p°a externa leverant
¨orer. Denna masteruppsats fokuserar p°a ett internationellt f¨oretag som erbjuder transporter
av bulkprodukter lastade i tankcontainrar via v¨ag, j¨arnv¨ag och sj¨o. I system av detta
slag utf¨ors obalanserade transporter av lastade tankcontainrar, vilket tvingar f¨oretaget till
att ompositionera tomma tankcontainrar. F¨oretaget motiveras av att unders¨oka om det
finns incitament till att vidare analysera eller m¨ojligtvis implementera en matematisk modell
som st¨odjer ompositioneringsbeslut f¨or tomma tankcontainrar. Ompositionerings beslut
baseras p°a kundorder samt antaganden om huruvida framtida efterfr°agan kommer uppst°a
eller ej. Problemet inkluderar att m¨ota efterfr°agan och tillh¨orande krav fr°an f¨oretagets kunder.
Kraven specificerar vilken tid leverans ska ske, vilket skick tankcontainern b¨or vara i
samt vilken typ av tankcontainer som efterfr°agas. En dynamisk blandad heltalsmodell som
¨ar anpassad f¨or intermodal transporter samt den varierade efterfr°agan av olika dimensioner
av tankcontainrar utvecklas, med syftet att generera taktiska beslut f¨or det aktuella allokeringsproblemet.
Mer specificerat ¨ar m°alet att best¨amma en optimal distributionsstrategi
inom f¨oretagets transportn¨atverk.
Modellen utvecklas och valideras steg f¨or steg och dess funktionaliteter demonstreras genom
en k¨anslighetsanalys baserat p°a det Europeiska n¨atverket inkluderat i v°ar fallstudie. Fallstudien
inkluderar tre olika scenarion f¨or allokering av tomma tankcontainrar. Vidare nyttjas
topologin av n¨atverket i fallstudien till att utf¨ora slumpm¨assigt utvalda instanser f¨or att
utv¨ardera modellen. Dessa ber¨akningsresultat visar att modellen finner l¨osningar av god
kvalitet och indikerar att det finns rum f¨or f¨orb¨attringar g¨allande f¨ordelningen av transportmedel.
En utf¨orlig k¨anslighetsanalys presenterar vilken effekt modellens parametrar
har p°a modellens utf¨orande. Vi anv¨ander slumpm¨assigt utvald data f¨or k¨anslighetsanalysen
och betonar vissa funktionaliteter av modellen samt delger insikter om modellens beteende
Early stress detection in forest trees using a nanobody-functionalized electrochemical biosensor for ascorbate peroxidase
Get PDFForest environments are exposed to multiple stressful factors of both abiotic and biotic nature such as heavy metal contamination, drought, or pest infestations which may lead to their massive decline. We designed a comprehensive approach for isolating, producing and functionalizing reagents suitable for the affordable detection of forest plant stress biomarkers with the aim to provide quantitative data to assess plant stress fluctuation and, possibly, to design mitigation strategies. We first optimized a panning protocol to recover nanobodies targeting shared sequences that could cross-react with both Pisum sativum and Populus nigra ascorbate peroxidase (APX). After their production as recombinant constructs and their extensive biophysical and biochemical characterization, such reagents were exploited as the immunocapture element of an electrochemical biosensor conceived as a potential point-of-care device. Such biosensor could detect both pea and poplar APX in leaf extracts and could be used to clearly discriminate between control and heavy metal-stressed poplar plants based on their APX activity, even before the appearance of any phenotypic symptom. The combination of fast and inexpensive reagent production with the development of portable diagnostics opens the opportunity for large-scale, on-site surveys of forest trees.Forest environments are exposed to multiple stressful factors of both abiotic and biotic nature such as heavy metal contamination, drought, or pest infestations which may lead to their massive decline. We designed a comprehensive approach for isolating, producing and functionalizing reagents suitable for the affordable detection of forest plant stress biomarkers with the aim to provide quantitative data to assess plant stress fluctuation and, possibly, to design mitigation strategies. We first optimized a panning protocol to recover nanobodies targeting shared sequences that could cross-react with both Pisum sativum and Populus nigra ascorbate peroxidase (APX). After their production as recombinant constructs and their extensive biophysical and biochemical characterization, such reagents were exploited as the immunocapture element of an electrochemical biosensor conceived as a potential point-of-care device. Such biosensor could detect both pea and poplar APX in leaf extracts and could be used to clearly discriminate between control and heavy metal-stressed poplar plants based on their APX activity, even before the appearance of any phenotypic symptom. The combination of fast and inexpensive reagent production with the development of portable diagnostics opens the opportunity for large-scale, on-site surveys of forest trees
Time and Passing in the Poetry of Lili Novy
Get PDFV magistrski nalogi sem predstavila poezijo Lili Novy, ki je bila izdana v dveh pesniških zbirkah Temna vrata (1941) in Oboki (1959) ter v pesniški zbirki Črepinje in druge pesmi (2005), v kateri so izbrane pesmi napisane v nemškem jeziku in prevedene v slovenski jezik. V nalogi sem se osredotočila na motive časa, minevanja in starosti. Prva dva dela temeljita na pregledu in povzemanju teoretskih in literarno teoretskih besedil. V prvem delu sem predstavila nekatere teorije, ki so skušale razložiti pojem časa. V drugem delu sem predstavila recepcijo poezije Lili Novy, ki je bila ob izidu njenih dveh pesniških zbirk skromna in še danes ni veliko raziskovalcev in raziskovalk, ki bi se z njeno poezijo ukvarjali. Kljub temu, da poeziji priznavajo kvaliteto, še vedno ni sprejeta v slovenski literarni kanon. V tretjem delu sem analizirala poezijo s fokusom na motivih časa in minevanja, ugotavljala sem, kako se lirski subjekt sooča s tem, da čas mineva in s tem prinaša spremembe, tako kolektivno kot v intimnem doživljanju posameznika.In my master\u27s thesis, I presented the poetry of Lili Novy, which was published in two collections of poetry Temna vrata (Dark Door, 1941) and Oboki (Arches, 1959), as well as in the poetry collection Črepinje in druge pesmi (2005), in which selected poems are written in German and translated into Slovenian. In the assignment, I focused on the motifs of time, passing and age. The first two parts are based on the review and summarization of theoretical and literary theoretical texts. In the first part, I presented some theories that tried to explain the concept of time. In the second part, I presented the reception of Lili Novy\u27s poetry, which was modest at the time of the publication of her two collections of poetry and to this day there are not many researchers who would deal with her poetry. Despite the fact that her poetry is recognized for its quality, it is still not accepted into the Slovenian literary canon. In the third part, I analysed her poetry with a focus on the motifs of time and passing, noting how the lyrical subject copes with the fact that time passes and thus brings changes, both collectively and in the intimate experience of the individual
The Pierre Auger Observatory open data
Get PDFThe Pierre Auger Collaboration has embraced the concept of open access to their research data since its foundation, with the aim of giving access to the widest possible community. A gradual process of release began as early as 2007 when 1% of the cosmic-ray data was made public, along with 100% of the space-weather information. In February 2021, a portal was released containing 10% of cosmic-ray data collected by the Pierre Auger Observatory from 2004 to 2018, during the first phase of operation of the Observatory. The Open Data Portal includes detailed documentation about the detection and reconstruction procedures, analysis codes that can be easily used and modified and, additionally, visualization tools. Since then, the Portal has been updated and extended. In 2023, a catalog of the highest-energy cosmic-ray events examined in depth has been included. A specific section dedicated to educational use has been developed with the expectation that these data will be explored by a wide and diverse community, including professional and citizen scientists, and used for educational and outreach initiatives. This paper describes the context, the spirit, and the technical implementation of the release of data by the largest cosmic-ray detector ever built and anticipates its future developments
Machine learning-based analyses using surface detector data of the Pierre Auger Observatory
Get PDFThe Pierre Auger Observatory is the largest detector for the study of extensive air showers induced
by ultra-high-energy cosmic rays (UHECRs). Its hybrid detector design allows the simultaneous
observation of different parts of the shower evolution using various detection techniques. To
accurately understand the physics behind the origin of UHECRs, it is essential to determine their
mass composition. However, since UHECRs cannot be measured directly, estimating their masses
is highly non-trivial. The most common approach is to analyze mass-sensitive observables, such as
the number of secondary muons and the atmospheric depth of the shower maximum.
An intriguing part of the shower to estimate these observables is its footprint. The shower footprint is detected by ground-based detectors, such as the Water-Cherenkov detectors (WCDs) of the Surface Detector (SD) of the Observatory, which have an uptime of nearly 100%, resulting in a high number of observed events. However, the spatio-temporal information stored in the shower footprints is highly complex, making it very challenging to analyze the footprints using analytical and phenomenological methods. Therefore, the Pierre Auger Collaboration utilizes machine learning-based algorithms to complement classical methods in order to exploit the measured data with unprecedented precision. In this contribution, we highlight these machine learning-based analyses used to determine high-level shower observables that help to infer the mass of the primary particle, with a particular focus on analyses using the shower footprint detected by the WCDs and the Surface Scintillator Detectors (SSD) of the SD. We show that these novel methods show promising results on simulations and offer improved reconstruction performance when applied to measured data
Subluminal pulses in the surface-scintillator detectors of AugerPrime
Get PDFIn extensive air showers, the signals from the electromagnetic and muonic components typically span a few microseconds in scintillation detectors.
Neutrons are the only stable neutral hadrons over the timescale of air showers.
They lose energy exclusively through hadronic interactions and quasi-elastic scattering, which results in their high abundance at ground level.
These neutrons can produce delayed pulses in scintillation detectors, appearing up to several milliseconds after the primary shower signal.
This allows us to probe hadronic interactions in the development of air showers.
In this study, we characterize such subluminal pulses using the first measurements from the scintillator surface detectors of the AugerPrime upgrade of the Pierre Auger Observatory