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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Ett paket, flera valmöjligheter : En kvalitativ studie om hur konsumenten värderar leveransattribut vid val vid sista-milen leverans

Lyckander, Emelie, Ydehall, Nova January 2024 (has links)
Dagens konsumenter skiljer sig från tidigare generationer, konsumtionsmönstret har förändrats, en betydande faktor till detta är den ökande populariteten av e-handel. Flexibiliteten och friheten som konsumenten får via handel online har skapat högre krav och förväntningar på företagen. Till följd av en växande e-handeln ställs även större krav på företagens logistiklösningar, och extra viktig blir slutskedet i försörjningskedjan, den sträcka som går mellan konsumenten och e-handlaren och som kallas sista-milen. Sista- milen är den logistikaktivitet som är mest resurskrävande för e-handlaren och i kombination med konsumentens ökade förväntningar på företagen blir betydelsen av effektiv hantering av sista-milen ännu mer påtaglig.  I dag finns flertalet kvantitativa studier som undersöker hur företag på bästa sätt kan optimera och effektivisera sina sista-milen leveranser. Bristen på kvalitativ forskning som fokuserar på att förstå konsumenten, dennes värderingar och bakomliggande resonemang när de fattar beslut om sista-milen leverans skapar ett forskningsgap som studien ämnar att fylla. Syftet med studien är därför att undersöka den beslutsprocess konsumenten genomgår inför ett beslut om sista-milen leverans och vilka påverkansfaktorer som kan påverka konsumenten inför ett val. Syftet är även att undersöka och analysera hur konsumenten värderar leveransattributen leveranskostnad, returmöjligheter, leveranstid, bekvämlighet och miljömässig hållbarhet i sitt val av sista-milen leverans. Därmed är studiens forskningsfråga följande:  Hur värderar konsumenter olika leveransattribut vid val av sista-milen leverans?  För att sammanfatta samtligt teoretiskt innehåll som presenteras i den teoretiska referensramen och illustrera hur delarna kan vara korrelerade med varandra har en sammanfattande modell skapats. Modellen är en processbeskrivning som illustrerar hur beslutsprocessen kan se ut när konsumenten värderar leveransattribut och fattar beslut om sista-milen leveranser, samt vilka påverkansfaktorer som kan påverka konsumenten inför valet. För att samla in relevant empiriskt material genomfördes semi-strukturerade intervjuer, vilket gav upphov till resonemang och värderingar från respondenterna viktiga för att besvara studiens syfte och forskningsfråga. Eftersom utbudet av sista-milen leveranser varierar beroende på var i Sverige konsumenten bor valde författarna att begränsa området till att undersöka respondenter bosatta i Norrland. Genom en urvalsprocess valdes tio respondenter ut för att bidra med insikter, erfarenheter och tankar kring ämnet.  Studiens resultat indikerar att konsumenternas värdering av leveransattributen är i hög grad situationsberoende, men generellt sett prioriterar konsumenten leveranskostnad och bekvämlighet högre än andra leveransattribut. Hur konsumenter värderar attributet leveranstid gick emot tidigare forskning, anledningen kan vara konsumenternas geografiska plats. Det samma gällde konsumenternas krav på sista-milen leveranser som inte visade sig vara allt för krävande som tidigare forskning visat, i stället fanns en förståelse för att leverantörerna hanterar många paket och konsumenterna önskade uppdateringar och kommunikation om leverans avvek från det som var bestämt. Vilket leder in på studiens bidrag av ny kunskap i form av ytterligare ett leveransattribut, service och kommunikation. Övervägande hade företagens service och kommunikationsförmåga en stor påverkan på konsumentens beslutsprocess vid val av sista-milen leverans.
82

The effect of lower sea level on geostrophic transport through the Florida Straits during the last glacial maximum

Ionita, Dana 14 January 2009 (has links)
We investigate the effect of a 120 meter sea level drop on transport through the Caribbean Sea and the Florida Straits during the Last Glacial Maximum (LGM) relative to the present, using the Regional Ocean Modeling System (ROMS). A geostrophic transport estimate for the Florida Straits suggests the LGM Florida Current was weaker than today by one third, inferring a likely decrease in the North Atlantic overturning circulation by 12-15 Sv. A possible impact of a shallower LGM Florida Straits sill depth on the Florida Current has been suggested. Our model results show that the volume transport through the Florida Straits is slightly reduced in a lower sea level model simulation when compared to a control sea level simulation (34.8 ± 2.0 Sv vs. 39.8 ± 2.3 Sv). The difference in transport is of the order of 5 Sv, representing a maximum limit to the LGM flow reduction due to sea level change. Therefore the change in sill depth between the LGM and the present is unlikely to have been a cause of the entire observed flow reduction.
83

Fabrication et caractérisation de transistors MOS à base de nanofils de silicium empilés et à grille enrobante réalisés par approche Gate-Last pour les noeuds technologiques sub-7 nm. / Fabrication and Characterization of Gate-All-Around Stacked-Nanowire/Nanosheet MOS transistors realized by a Gate-Last approach for sub-7 nm technology nodes.

Gaben, Loic 19 October 2017 (has links)
La diminution de la taille des transistors actuellement utilisés en microélectronique ainsi que l’augmentation de leurs performances demeure encore au centre de toutes les attentions. Cette thèse propose d’étudier et de fabriquer des transistors à base de nanofils empilés. Cette architecture avec des grilles enrobantes est l’ultime solution pour concentrer toujours plus de courant électrique dans un encombrement minimal. Les simulations ont par ailleurs révélé le potentiel des nanofeuillets de silicium qui permettent à la fois d’optimiser l’espace occupé tout en proposant des performances supérieures aux dispositifs actuels. L’importance de l’ajout de certaines étapes de fabrication a également été soulignée. En ce sens, deux séries d’étapes de fabrication ont été proposées : la première option vise à minimiser le nombre de variations par rapport à ce qui est aujourd’hui en production tandis que la deuxième alternative offre potentiellement de meilleures performances au prix de développements plus importants. Les transistors ainsi fabriqués proposent des performances prometteuses supérieures à ce qui a pu être fabriqué dans le passé notamment grâce à l’introduction de contraintes mécaniques importantes favorables au transport du courant électrique. / The future of the transistors currently used in Microelectronics is still uncertain: shrinking these devices while increasing their performances always remains a challenge. In this thesis, stacked nanowire transistors are studied, fabricated and optimized. This architecture embeds gate all around which is the ultimate solution for concentrating always more current within a smaller device. Simulations have shown that silicon nanosheets provide an optimal utilization of the space with providing increased performances over the other technologies. Crucial process steps have also been identified. Subsequently, two process flows have been suggested for the fabrication of SNWFETs. The first approach consists in minimizing the number of variations from processes already in mass production. The second alternative has potentially better performances but its development is more challenging. Finally, the fabricated transistors have shown improved performances over state-of-the-art especially due to mechanical stress induced for improving electric transport.
84

Reconstitution de la végétation et du climat au cours du dernier interglaciaire à partir de la séquence pollinique du lac le plus ancien d'Europe : le lac Orhid (FYROM) / Vegetation and climate reconstruction during the last interglacial : the pollen record of Lake Ohrid (Republic of Macedonia) the oldest European lake

Sinopoli, Gaia 21 December 2017 (has links)
Cette thèse est centrée sur les changements paléoenvironnementaux et climatiques survenus dans le période entre 130 et 70 ka (Dernier Complexe Interglaciaire), pour étudier la variabilité du climat à long terme sur l'environnement, sur la base des données de pollen à haute résolution provenant des sédiments du lac Ohrid (Albanie / F.Y.R.O.M), le plus ancien lac d'Europe. La reconstruction du climat obtenue à partir des données polliniques est basée sur un intervalle plus large, 160-70 ka.Le matériel pollinique provient des sédiments prélevés en 2013, dans le cadre du projet SCOPSCO (Scientific Collaboration On Past Speciation Conditions in Lake Ohrid) dont le carottage a été financé par l'ICDP (International Continental Scientific Drilling Program). Pendant la campagne de carottage, 6 carottes parallèles ont été prélevées à partir de l’épicentre du lac, obtenant une séquence composite extraordinaire de 569 m (DEEP).Les 247.8 m supérieurs de la carotte DEEP ont été datés et ils couvrent les derniers 637 ka. Nous avons amélioré le modèle d’âge pour le Dernier Complexe Interglaciaire et en particulier pour la transition entre MIS6 et 5, en comparant les données polliniques avec d'autres proxies de la carotte DEEP et de la Méditerranée. Cela rend le lac Ohrid extrêmement important car pour les autres enregistrements de la région Européenne, de telles contraintes chronologiques ne sont pas disponibles.L'analyse des premiers 200 m de la carotte DEEP, couvrant les derniers 500 ka, a été étudiée avec une résolution de 1,6 ka. La séquence a révélé une alternance entre des ouvertures forestières et périodes boisées reflétant une cyclicité glaciaires-interglaciaires comparable à celle de la stratigraphie des isotopes marins. Parmi les différents cycles glaciaires-interglaciaires, l’analyse pollinique à haute résolution du Dernier Complexe Interglaciaire montre l'alternance classique de périodes caractérisées par la forêt (interstades, périodes chaudes et humides) et la végétation ouverte (stades, et périodes sèches), ressemblant clairement à la succession végétale et climatique bien connue des autres séquences européennes.Concernant le Dernier Interglaciaire (ou Eémien, 128-112 ka), l'analyse pollinique et les reconstructions quantitatives climatiques basées sur ces dernières identifient trois phases clés : une phase initiale caractérisée par un réchauffement soudain (propagation des forêts mésophiles), puis une diminution des températures associées à des conditions humides (expansion de Carpinus betulus) et à la fin un établissement progressif vers des conditions froides et sèches jusqu'à la fin de Eemian à 112 ka, confirmant l’hypothèse déjà avancée par plusieurs études antérieures basées sur des séquences polliniques européennes , à savoir que l’Eemien n'était pas une période climatiquement stable.D’autres changements climatiques sont également visibles dans la région du lac Ohrid entre 112-70 ka et probablement liés à la succession d'événements froids enregistrés dans les carottes de glace du Groenland, associé à un affaiblissement de l’AMOC (Atlantic Meridional Overturning Circulation).Ce travail a permis de fournir une nouvelle séquence de référence pollinique pour le Dernier Complexe Interglaciaire en Europe. Ce travail a également permis de quantifier les paléoclimats pour la période 160-70 ka, encore peu étudiée en Europe, principalement dans le sud (<45 ° lat. N), où un seul enregistrement a été étudié pour toute la période, avec une résolution temporelle élevée.Sur la base de ces résultats, le lac Ohrid apparait comme un site clé pour l'étude des changements climatiques survenus à une échelle centenaire et millénaire dans une région de moyenne altitude entre les régions européennes et méditerranéennes, fournissant en outre des nouvelles informations sur la connexion entre les oscillations climatiques de la région méditerranéenne et de l'Hémisphère du Nord. / This thesis is focussed on the palaeonvironmental and climatic changes occurred during the period between 130 and 70 ka (Last Interglacial Complex), with the aims to investigate the long-term climate variability on environment, on the basis of high resolution pollen data from Lake Ohrid sediments (Albania/F.Y.R.O.M. border), the oldest lake in Europe. The climate reconstruction obtained from pollen data is based on a wider interval, 160-70 ka.The investigated pollen material comes from the sediments retrieved in spring 2013 in the frame of the project SCOPSCO (Scientific Collaboration On Past Speciation Conditions in Lake Ohrid) whose drilling was financed by the ICDP (International Continental Scientific Drilling Program). During the drilling campaign 6 parallel cores have been collected from the depocenter of Lake Ohrid obtaining an extraordinary composite sequence 569 m long (DEEP).The upper 247.8 m of DEEP core have been dated using tephrostratigraphic information and tuning of biogeochemical proxy data to orbital parameters and covers the last 637 ka. In the framework of this careful temporal establishment, an even more precise chronology for the Last Interglacial Complex, and in particular for the transition between MIS6 and 5, was obtained by comparing pollen data from the same period with other DEEP and Mediterranean proxies. This make Lake Ohrid extremely important because for the other records from Mediterranean and European area such chronological constrains are not available and so the chronologies are less precise.The pollen analysis results come from the uppermost 200 m of the DEEP core (covering the last 500 ka) and revealed a succession of non-forested and forested periods clearly connected with glacial–interglacial cycles of the marine isotope stratigraphy.Among the different glacial-interglacial cycle, the new high-resolution pollen stratigraphy of the Last Interglacial Complex shows the classical alternation of periods characterized by forest (interstadials, warm and wet periods) and open vegetation (stadials, cold and dry periods), clearly resembling the well-known vegetational and climate succession of other European records.Concerning the Last Interglacial (or Eemian, 128-112 ka, roughly equivalent to MIS5e), pollen analysis and climate quantitative reconstructions identify three key phases with a slight different timing, with an initial phase characterized by a sudden warming (propagation of mesophilous forests), then a decrease of temperatures associated with wet conditions (expansion of Carpinus betulus) and at the end a progressive establishment towards cold and dry conditions until the termination of Eemian at 112 ka, confirming what other previous studies on European records said, namely Eemian was not a stable period.Several abrupt events are in also identified, during the successive stadials and interstadials (Early Last Glacial), probably correlated to the succession of cold events recorded in the Greenland ice core records, associated to a weakening of the North Atlantic Meridional Overturning Circulation.This work provides a new pollen reference sequence for the Last Interglacial Complex in Europe and concerning climate reconstruction provides new information for a period (160-70 ka, from the last part of Riss Glaciation to the beginning of Würm Glaciation) still poorly investigated in Europe, mostly in the south (< 45° lat. N), where only one record has been studied for the whole interval, with high resolution time.According to my results, Lake Ohrid can be considered a key role site for the investigation of the climatic changes occurred in centennial and millennial scale in a region of mid-altitude between European and Mediterranean areas, providing furthermore new evidence for the connection between the Europe and Northern Hemisphere climate oscillations.
85

Ostéométrie et migration(s) du renne (Rangifer tarandus) dans le Sud-Ouest de la France au cours du dernier Pléniglaciaire et du Tardiglaciaire (21500 - 13000 ca. BP) / Osteometry and migration(s) of reindeer (Rangifer tarandus) in South-West France during the last Pleniglacial and the last Glacial (21500 - 13000 ca. BP)

Kuntz, Delphine 28 November 2011 (has links)
Cette recherche doctorale entend caractériser les fluctuations morphologiques des rennes paléolithiques du Sud-Ouest de la France consécutives aux changements climatiques. En effet, le dernier Pléniglaciaire et le Tardiglaciaire (entre 21 500 - 13 000 cal. BP) ont constitué des périodes de contraintes paléoclimatiques et paléoenvironnementales particulièrement fortes, qui ont occasionné, directement ou indirectement, des répercussions sur la taille corporelle des populations de rennes. Les séries analysées dans le cadre de ce travail proviennent tant du registre actuel que fossile. Plusieurs échantillons de populations actuelles (Norvège, Finlande, Groenland) ont ainsi été analysés, afin de tester notre méthodologie et d’envisager des comparaisons morphologiques avec les populations passées. Le corpus paléolithique comporte 29 assemblages naturels et anthropiques du Sud-Ouest de la France, datés majoritairement du dernier Pléniglaciaire et du Tardiglaciaire. La méthode du Variability Size Index appliquée récemment sur le Renne paléolithique posant des problèmes, s’agissant notamment de la détermination du sex-ratio d’un assemblage, du caractère significatif ou non des différences morphologiques -isométriques et allométriques - observées..., nous avons eu recours à une nouvelle méthodologie combinant plusieurs outils statistiques appliqués à un nouvel indice de taille (VSI* : Variability Size Index modifié). Les analyses ostéométriques et statistiques que nous avons effectuées tendent à identifier des fluctuations morphologiques temporelles attestant d’adaptations de l’espèce. D’un point de vue synchronique, nos résultats permettent de rejeter l’hypothèse précédemment soutenue de différences entre les rennes tardiglaciaires des Landes d’une part et du secteur Dordogne/Gironde d’autre part. Les données saisonnières tendent toutefois à indiquer une absence de migrations de grande ampleur des rennes selon cet axe Nord/Sud. L’existence de populations distinctes est toutefois proposée entre les rennes des Landes et ceux du Bassin de l’Aude. Le Sud-Ouest de la France, à la fin du Paléolithique supérieur, aurait été occupé de manière pérenne par des troupeaux de rennes, dont le comportement migratoire reste cependant à déterminer plus précisément. / This doctoral research aims at characterizing morphological fluctuations resulting from climate change in palaeolithic reindeers from Southwest France. Indeed, the Last Pleniglacial and the Last Glacial (between 21 500 - 13 000 cal. BP) constituted periods of particularly strong palaeoclimatic and palaeoenvironmental constraints, which ended, either directly or indirectly, in repercussions on the body size of reindeer populations. The series analyzed within the framework of this work result from both current and fossil registers. Several samples of current populations (Norway, Finland, and Greenland) were thus analyzed, in order to experiment our methodology and envisage morphological comparisons with the past populations. The palaeolithic corpus is composed of 29 natural and anthropological assemblages of Southwest France, dated mainly from the Last Pleniglacial and the Last Glacial. Since the Variability Size Index method recently applied to palaeolithic Reindeer raises issues, particularly relating to the determination of an assemblage’s sex-ratio, to the characterization or not of observed morphological differences –either isometric and allometric–, we decided to use a new methodology combining several statistical tools applied to a new size index (VSI*: modified Variability Size Index). Osteometric and statistical analyses that we performed tend to identify temporal morphological fluctuations, demonstrating adaptations of the specie. From a synchronic standpoint, our results allow to reject the hypothesis previously asserted regarding differences between Last Glacial reindeers from Landes on the one hand and the Dordogne/Gironde sector, on the other hand. Seasonal data however tend to indicate an absence of large-scale migrations of reindeers according to such a North/South axis. Nonetheless, the existence of different populations between reindeers of Landes and those of the Aude basin is proposed. Hence, Southwest France, at the end of the upper Palaeolithic, would have been occupied continuously by reindeer herds, the migratory behaviour of which however remains to determine more exactly.
86

Mejoramiento de la productividad en proyectos de saneamiento básico rural; caso de estudio: Construcción de casetas sanitarias ejecutados por la empresa SICMA S.A.C. en la region de Puno durante los periodos 2016 – 2017 / Improvement of productivity in rural basic sanitation projects; case study: Construction of sanitary huts executed by the company SICMA S.A.C. in the region of Puno during the periods 2016 - 2017

Moscairo Chura, Juan Brayan, Valdivia Daza, Reynaldo Victor 16 March 2019 (has links)
El sector construcción en el Perú es uno de los más dinámicos en la economía del país, se debe a que en los últimos años el gobierno ha venido impulsando la inversión pública, mediante la ejecución de proyectos de infraestructura y en especial a los de saneamiento básico rural; razón por la que la empresa SICMA S.A.C. viene ejecutando proyectos similares en distintos lugares de la región de Puno. El objetivo de esta investigación es determinar el estado actual de la productividad en 9 proyectos de saneamiento básico rural, durante los años 2016 y 2017. Como resultado de análisis de estos datos se determinó que la productividad de la mano de obra en los proyectos ejecutados de forma tradicional es muy baja debido a que no se tiene una adecuada planificación mucho menos control de la ejecución de estos proyectos. Como otro objetivo de esta investigación se ha implementado el sistema Last Planner, en uno de los proyectos de saneamiento básico rural de similares características que las anteriores, obteniéndose mejoras respecto al desempeño de la mano de obra incrementándose la productividad. Estas mejoras fueron evidenciadas mediante la comparación de los rendimientos y valores de ocupación del tiempo, obtenidos de forma tradicional con los obtenidos implementando el sistema Last Planner; quedando con esto demostrado de que es posible la aplicación de herramientas basadas en la filosofía Lean Construction en la ejecución de este tipo de proyectos y que con ellas se puede mejorar la productividad y reducir los plazos de ejecución. / The construction sector in Peru is one of the most dynamic in the economy of the country, it is because in recent years the government has been promoting public investment, through the execution of infrastructure projects and especially basic sanitation rural; reason why the company SICMA S.A.C. It has been executing similar projects in different places in the Puno region. The objective of this research is to determine the current state of productivity in 9 rural basic sanitation projects, during the years 2016 and 2017. As a result of analysis of these data, it was determined that the productivity of the labor force in the executed projects of Traditional way is very low because you do not have adequate planning much less control of the execution of these projects. As another objective of this research, the Last Planner system has been implemented, in one of the rural basic sanitation projects with similar characteristics as the previous ones, obtaining improvements regarding the performance of the workforce, increasing productivity. These improvements were evidenced by the comparison of the yields and values of occupation of time, obtained in a traditional way with those obtained by implementing the Last Planner system; remaining with this demonstrated that it is possible the application of tools based on the philosophy Lean Construction in the execution of this type of projects and that with them can improve the productivity and reduce the terms of execution. / Trabajo de investigación
87

Navigating the concrete jungle : Route planning in urban last-mile delivery

Ebenspanger, Thomas January 2022 (has links)
The e-commerce market has developed massively since the 1990ies. In addition to a general change of shopping behavior, the COVID-pandemic increased the importance of online shopping. This study is about the transportation of e-commerce parcels on the last mile in urban areas, so called last-mile delivery. Special focus is put on innovative last mile solutions that reduce the externalities related to last-mile delivery. There are several factors that complicate the delivery on the last mile such as congestion, driving restrictions and meeting time-windows for customers. This study investigates to what extent the route planning for a fleet of vehicles can account for these various requirements and restrictions. The route planning was conducted in the GIS software ArcGIS Pro using the vehicle routing problem. The routes could be successfully planned and consider most of the relevant factors for last-mile delivery operations. The results indicate that traffic and congestion in cities can be accounted for which results in an average driving speed of 20km/h. The planned routes also indicate that not even 20% of the vehicle’s cargo capacity was used and that 60-65% of the total time is spent driving between orders. The study and its results are relevant to businesses and researchers in the field of last-mile delivery as the analysis of a real-world scenario highlights the possibilities and limitations of route planning on the last mile.
88

Production Planning With the Last Planner System on Construction Projects in Sweden : An Exploratory Case Study of Challenges and Improvement Measures / Produktionsplanering med Last Planner systemet på byggprojekt i Sverige : En explorativ fallstudie av utmaningar och förbättringsåtgärder

Dag, Maria, Garg, Apoorv January 2019 (has links)
One of the main assumptions in conventional production process is that each component or part of the production process can be controlled separately as if they are not dependent on anything. This assumption gives rise to problems such as need of effective collaboration with different actors and constraints in budgets. Conventional planning process also causes delay as well as cost overruns which ultimately leads to reduction in productivity.The Last Planner system, LPS, is a tool used in the construction sector with the goal of streamlining production. The tool has several advantages, for example, to make collaboration between different actors more efficient, achieve a better workflow and increase production efficiency. The purpose of this masters’ thesis is to explore how two construction projects in Stockholm work with LPS. Apart from the fact that LPS provides many advantages in the production planning of the projects, this study aims to explore the challenges that they face while working with LPS. The goal of this study is to be able to suggest improvement measures for the challenges that the projects are facing.Semi-structured interviews were conducted on both projects to understand how they work with LPS and what challenges they face. The results section contains the information from the interviews. That is then discussed against the theory on which the Last Planner system is built.The conclusion of this study is that the production planning in the projects differs from how the tool should be used according to the framework of LPS. Learning, which emphasizes what has been done during the project, is a phase in LPS's framework. According to one of the founders of the LPS system, ‘learning’ is the most important phase. However, due to the lack of time, the studied projects were not able to involve the learning phase into their production planning. The projects faced several challenges, including repeated changes from the design teams, which entailed new actions during the project. Also, the involvement of the construction workers in the planning phases came out as a big challenge for the managers. Furthermore, communication problems and lack of cooperation with subcontractors is also present. Some of the improvement measures suggested to meet the challenges are that managers should increase commitment to involve especially construction workers in the planning phases, create nucleus teams, create a standard protocol for how production planning should be implemented, and improve visual planning to enhance communication. / I de traditionella produktionsprocesserna har det antagits att olika komponenter kan styras separat d.v.s. att de är oberoende. Detta antagandet har gett upphov till problem som till exempel försämrat samarbete mellan olika aktörer. Den traditionella produktionsprocessen har också lett till förseningar och kostnadsöverskridanden i projekt.Last Planner-systemet, LPS, är ett verktyg som används inom byggsektorn med målet att effektivisera produktionen. Förutom att effektivisera produktionen är syftet att involvera byggarbetare i planeringsfaserna. Verktyget har flera fördelar, till exempel att effektivisera samarbeten mellan olika aktörer, uppnå ett konstant arbetsflöde och ökad effektivitet i produktionen. Syftet med denna uppsats är att utforska hur två byggprojekt i Stockholm arbetar med LPS. Bortsett från att LPS tillför många fördelar i projektens produktionsplanering har denna uppsats som mål att utforska vilka utmaningar projekten står inför kring arbetet med LPS. Målet är att kunna föreslå eventuella förbättringar för att möta utmaningarna som projekten står inför.Semistrukturerade intervjuer genomfördes på båda projekten för att förstå hur de arbetar med LPS och vilka utmaningar de står inför. Resultatavsnittet redovisar informationen från intervjuerna, som sedan diskuteras i relation till teorin som LPS bygger på.Slutsatsen av denna uppsats är att det skiljer sig mellan hur verktyget används i praktiken jämfört med vad ramverket för LPS står för. Att ta lärdom av vad som gjorts under projektet är en fas i LPS ramverk. Enligt en av grundarna av LPS-systemet är ’lärande’ den viktigaste fasen. Men på grund av tidsbrist har inte projekten som denna studie undersökte kunnat genomföra den fasen. Projekten stod inför flera utmaningar, bland annat upprepade ändringar från designteamen, som ledde till nya åtgärder under projektet, att involvera byggarbetare i planeringsfaserna, kommunikationsproblem mellan aktörer och bristande samarbete med underentreprenörer. Några förbättringsåtgärder är att chefer borde engagera sig mer för att involvera byggarbetare i planeringsfaserna, skapa ett standardprotokoll för hur produktionsplanering bör genomföras och förbättra den visuella planeringen för att uppnå bättre kommunikation.
89

Breaking the Time Preference : A study of home delivery

Alvinsson, Gustav January 2022 (has links)
Bakgrund. E-handel ökar ständigt, och med det även frakt av ehandelsvaror. Frakten som skrivs om i den här studien syftar till den frakt som sker mellan en återförsäljare och en slutkonsument. Denna är i texten kallad last-mile delivery. Denna är identifierad som mycket kostnadsbärande för återförsäljare och därför har ansträngningar gjorts för att ta reda på vad som driver konsumentpreferenser vid frakt av ehandelsvaror. För att bredda det här fältet och den nuvarande kunskapen inom område har den här studien introducerat tidspreferensteori som underlag och adderat betalningsfördröjning som attribut vid last-mile delivery för att se vilken effekt detta har på preferenser vid fraktval. Syfte. Syftet med den här studien är att ta reda på hur en fördröjd betalning kan påverka preferenserna för olika last-mile delivery-alternativ. Överlag syftar också studien till att bredda kunskapen inom området. Detta görs alltså med introduktionen av tidspreferensteori till området. Metod. Studien är en experimentstudie med en ansluten enkät. Enkäten gjordes i tre utföranden och skickades ut i tre distinkta experimentgrupper. Därefter testades datan med ett icke-parametriskt proportionstest för att se om det fanns någon signifikant mängd svar som stödjer att en fördröjd betalning påverkar konsumentens val av last-mile delivery-alternativ. Resultat. Resultaten av studien visar att det inte finns någon koppling mellan en fördröjd betalning och ändrade konsumentbeteenden i fraktpreferenser. Överlag så valdes fraktalternativet med lägst frakt. Detta är något som går igen i flera tidigare studier där man kommit fram till att fraktkostnad och leveranshastighet är de två mest betydelsefulla aspekterna av frakten. Det enda scenariot som visade någon förändring i preferens var då produkten vid köpet var en dyr sådan. Huruvida preferensskiftet går att tillskriva den fördröjda betalningen förblir oklart, men inte osannolikt. Slutsatser. Slutsatsen till studien blir att trots tidspreferens och fördröjd betalning användes i studien så gav de inget mervärde. Resultatet blev i linje med tidigare resultat. Att tidspreferensteorin inte höll för fraktpreferenserna kan haft att göra med studiedesignen. En framtida studie hade kunnat göra ett mer ingående arbete och fokusera ännu mer på tidspreferensen för att hitta nya resultat / Background. E-commerce is ever expanding, and with it, so is last-mile delivery. Last-mile delivery is the last part of any delivery from a retailer or etailer (online retailer) to a consumer. Last-mile delivery is one of the most costly parts of the supply chain for many etailers and as such efforts have been made to understand what drives preferences for last-mile delivery. To broaden this field, this study will introduce time preference theory to the last-mile delivery and examine if delayed payment of an online purchase has any effect on the last-mile deliver preferences.  Objectives. The objectives of this study are to examine if delayed payment of online purchases has any effect on the last-mile delivery preference for consumers, as well as broaden the knowledge on last-mile delivery preferences in general. This is done with the inclusion of time preference theory as an underlying theory.  Methods. The study is carried out through the use of an experiment study with an experiment survey. The survey was made into three different versions, distributed to three different experiment groups. The data was then tested with a non-parametric proportion test with varying values of proportion to see whether there was any significant proportion of the replies that were in favor of delay of payment having any effect on the consumer preference.   Results. The results of the study showed that consumers generally choose the last-mile delivery option with the lowest delivery fee. This is in line with previous findings which concluded that delivery fee and delivery speed are the two most important factors for consumers. The only case in which consumers indicated that there was any effect of the payment delay was in the case of an expensive product. Even then it is hard to rule out that it was not something else that brought this result.   Conclusions. The concluding findings of the study is that while time preference was added as an attribute for last-mile delivery, it had little to no effect. This may have been because of the study design of this study. For future research on the topic, examining time preference in a greater depth may give different findings from this study.
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UMA PROPOSTA DE INTEGRAÇÃO DO MODELO BIM AO SISTEMA LAST PLANNER

Rodrigues, Priscilla Borges de Freitas 23 March 2017 (has links)
Submitted by admin tede (tede@pucgoias.edu.br) on 2017-06-29T13:25:06Z No. of bitstreams: 1 PRISCILLA BORGES DE FREITAS RODRIGUES.pdf: 3855875 bytes, checksum: 11d800e90a7d8e85c9925dfdaa032c34 (MD5) / Made available in DSpace on 2017-06-29T13:25:07Z (GMT). No. of bitstreams: 1 PRISCILLA BORGES DE FREITAS RODRIGUES.pdf: 3855875 bytes, checksum: 11d800e90a7d8e85c9925dfdaa032c34 (MD5) Previous issue date: 2017-03-23 / This research had as main point to use the Building Information Modeling (BIM), as an integrated form with the logic of the Last Planner system in relation to the planning and control of the production in companies of the civil construction sector and, with that, a model that promotes this integration in order to improve efficiency in medium and short term planning, where the construction of the integration model involves the development of a plug-in for Revit®, capable of making the information available in a database also fed by other software, here titled “L7”, through which it becomes possible to insert the analytic structure of a work and other information about the consumption of the inputs and, thus, make it possible to establish the relation between each geometric element and their needs for manpower and material, making explicit the restrictions when training the Lookahead through visual management. The methodological approach adopted was Design Science Research, whose main objective is to develop an artifact capable of solving a real and relevant problem and, thus, to promote the advance of the theoretical knowledge about the subject and to contribute to the operation within the companies. The evaluation of the constructed model was made through an empirical study in a work into a mall of a construction company in Goiás, followed by two services in the formation of the Lookahead of the month of January and the work week plan of the four weeks. It was possible, through visual color management, to check tasks that had material and/or labor constraints, facilitating the formatting of medium-term planning and improving the efficiency of short-term planning. / Esta pesquisa envolveu-se com a utilização da modelagem da informação da construção (BIM) de maneira integrada à lógica do Last Planner no planejamento e controle da produção em empreendimentos do setor da construção civil. Para isso, a investigação teve como objetivo principal construir um modelo BIM integrador, de forma a atuar na melhoria do planejamento de médio e curto prazo. A construção do modelo de integração passou pelo desenvolvimento de um plug-in para o software Revit®, capaz de disponibilizar informações em um banco de dados alimentado por outro software de planejamento. O modelo BIM estruturado tornou possível estabelecer a relação entre cada elemento geométrico do projeto arquitetônico e suas necessidades de materiais, mão-deobra e especificações de projeto. A abordagem metodológica adotada na pesquisa foi a Design Science Research. A avaliação do modelo construído foi feita em um estudo empírico em obra de grande porte do setor de edificações. Foi possível, através da gestão visual, verificar as tarefas que possuíam restrições em relação a materiais, mão-de-obra e detalhamento de projeto, facilitando a elaboração do planejamento de médio prazo e melhorando a eficiência do planejamento de curto prazo.

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