Schnellläuferstrategien sind Lagerstrategien, welche den Durchsatz von Lagern durch geeignete Wahl der Lagerorte im Lager steigern. Die verschiedenen existierenden Strategien wurden bisher uneinheitlich beschrieben und umgesetzt. Aussagen zu Durchsatzsteigerungen fallen schwer. Die existierenden Strategien werden systematisiert und als Vergleichsbasis für die neue Strategie "Dynamische Zonierung" herangezogen. Die "Dynamische Zonierung" ist dabei sowohl die einfachste als auch die leistungsfähigste Schnellläuferstrategie. Dafür sorgt die konsequente Anwendung zweier Verfahren, welche bereits einzeln sinnvoll sind, aber erst gemeinsam ihr volles Potential entfalten: Erstens erübrigt die Abbildung der Verweildauerverteilung auf die Fahrzeitverteilung jegliche Zonierung. Damit entfallen die Aufwände für Planung und Berechnung von Zonengrenzen und -zuordnungen. Gleichzeitig kann so die bei Zonenbildung unvermeidliche Abbildungsunschärfe beseitigt werden. Eine von einer optimalen Zuordnung abweichende Lagerortwahl resultiert nun ausschließlich aus Prognosefehlern. Zweites stellt die lagereinheitsbasierte Verweildauerbetrachtung die korrekte Umsetzung des als optimal nachgewiesenen Cube-Per-Order-Kriteriums dar. Ohne Zwang zur Zonenbildung fehlen die der Verwendung lagereinheitsbasierter Verweildauern sonst entgegenstehenden algorithmischen Mehraufwände. Dass auch die Prognose lagereinheitsbasierter Verweildauern für Teile des Sortimentes nicht zu Mehraufwand sondern zur Vereinfachung des Verfahrens führt, spricht zusätzlich für die lagereinheitsbasierte Betrachtung. Auch bei herkömmlicher artikelorientierter Betrachtungsweise kann die Dynamische Zonierung dadurch Leistungsvorteile herausarbeiten. / Turnover-based storage strategies are strategies in warehousing which increase the system throughput by choosing favorable storage locations. Existing strategies have been described and implemented inconsistently when compared to each other. Statements on strategy gains are difficult. Therefore a categorization of turnover-based strategies is devised. The existing strategies serve as basis of comparison for the new strategy "Dynamic Zoning". "Dynamic Zoning" proves to be the simplest turnover-based strategy while giving the highest performance at the same time. This is accomplished by combining two methods. These methods are reasonable when used separately, but only reach their full potential when used together. First, mapping the dwell time (duration of stay) probability distribution to the travel time probability distribution lets zones become obsolete. Efforts to plan and calculate zones can be avoided and the inevitable imprecision when mapping to zones vanishes. Any deviation from the optimal storage location now results from errors in estimation. Second, dwell times must be based on unit loads which is the correct application of the cube-per-order-criterion for optimality. Without the need to use zones this does not result in extra effort to apply the strategy. For a part of the assortment the estimation of unit load dwell times is simpler than before too, making unit load dwell times even more appealing. However, even when using conventional article based dwell time estimates the strategy "Dynamic Zoning" results in higher performance than other strategies.

The use of short columns, higher carrier gas velocity and fast temperature programs in Comprehensive Two-Dimensional Gas Chromatography coupled to Time-of- Flight Mass Spectrometry (GC x GC/TOFMS) technique is expected to increase the speed of analysis up to several orders of magnitude when compared to conventional gas chromatography (GC) or gas chromatography/mass spectrometry (GC/MS). A systematic evaluation of the GC x GC/TOFMS configuration for high-speed applications has received little attention in the literature. The feasibility of High Speed Comprehensive Two-Dimensional Gas Chromatography coupled to Mass Spectrometry (High speed GC x GC/MS) for complex mixtures has been investigated in this thesis. A particular focus was placed on comparing conventional scanning quadrupole mass spectrometry (qMS) with a newly available non-scanning time-of-flight instruments (TOFMS). Experiments were carried out using GC/qMS, GC x GC/qMS, GC/TOFMS and GC x GC/TOFMS both in normal (slow) and fast temperature rates coupled with high frequency modulation in GC x GC. Initially a complex mixture consists of 24 semivolatile compounds was used as the analyte for the above purpose. In the initial experiments parameters like acquisition rate and duty cycle for qMS were determined to evaluate the effectiveness of the instrument for fast analysis. The practical duty cycle value obtained for the qMS was only about 18 % for single ion and one compound at a dwell time of 10 ms in SIM mode. In both high-speed GC/qMS and high-speed GC x GC/qMS techniques only about 40 % of the components in the complex mixture were found to be well separated. The acquisition rate of scanning instruments like qMS is incompatible for fast eluting peaks in high speed GC. TOFMS that has an acquisition rate of several hundred spectra per second offer the potential to define the fast GC peaks accurately. The high quality spectra from TOFMS also enable deconvolution of coeluting peaks in the complex mixtures. The advantage of the automated spectral deconvolution is demonstrated for the identification of the coeluting peaks in the complex mixtures. Coelution of peaks is also observed with highspeed GC/TOFMS technique. The high-speed GC x GC/TOFMS was also tested with two different analyte system ??? A pesticide mixture and platformate (an aromatic mixture) to evaluate the suitability for high-speed analysis of complex mixtures. A poor resolution was observed for the pesticide mixture in the two-dimensional plane and it appeared, as there was nearly no orthogonal separation in the second dimension. The platformate mixture displayed a better two-dimensional separation. Chromatographic peak resolution is not really a primary requirement for locating and identifying the coeluting compounds in high-speed GC x GC/TOFMS technique. However, it was observed that the high-speed GC x GC/TOFMS too faced problem to unscramble the mass spectra of those compounds with similar structure and sharing the same unique masses.

Schnellläuferstrategien sind Lagerstrategien, welche den Durchsatz von Lagern durch geeignete Wahl der Lagerorte im Lager steigern. Die verschiedenen existierenden Strategien wurden bisher uneinheitlich beschrieben und umgesetzt. Aussagen zu Durchsatzsteigerungen fallen schwer. Die existierenden Strategien werden systematisiert und als Vergleichsbasis für die neue Strategie "Dynamische Zonierung" herangezogen. Die "Dynamische Zonierung" ist dabei sowohl die einfachste als auch die leistungsfähigste Schnellläuferstrategie. Dafür sorgt die konsequente Anwendung zweier Verfahren, welche bereits einzeln sinnvoll sind, aber erst gemeinsam ihr volles Potential entfalten: Erstens erübrigt die Abbildung der Verweildauerverteilung auf die Fahrzeitverteilung jegliche Zonierung. Damit entfallen die Aufwände für Planung und Berechnung von Zonengrenzen und -zuordnungen. Gleichzeitig kann so die bei Zonenbildung unvermeidliche Abbildungsunschärfe beseitigt werden. Eine von einer optimalen Zuordnung abweichende Lagerortwahl resultiert nun ausschließlich aus Prognosefehlern. Zweites stellt die lagereinheitsbasierte Verweildauerbetrachtung die korrekte Umsetzung des als optimal nachgewiesenen Cube-Per-Order-Kriteriums dar. Ohne Zwang zur Zonenbildung fehlen die der Verwendung lagereinheitsbasierter Verweildauern sonst entgegenstehenden algorithmischen Mehraufwände. Dass auch die Prognose lagereinheitsbasierter Verweildauern für Teile des Sortimentes nicht zu Mehraufwand sondern zur Vereinfachung des Verfahrens führt, spricht zusätzlich für die lagereinheitsbasierte Betrachtung. Auch bei herkömmlicher artikelorientierter Betrachtungsweise kann die Dynamische Zonierung dadurch Leistungsvorteile herausarbeiten. / Turnover-based storage strategies are strategies in warehousing which increase the system throughput by choosing favorable storage locations. Existing strategies have been described and implemented inconsistently when compared to each other. Statements on strategy gains are difficult. Therefore a categorization of turnover-based strategies is devised. The existing strategies serve as basis of comparison for the new strategy "Dynamic Zoning". "Dynamic Zoning" proves to be the simplest turnover-based strategy while giving the highest performance at the same time. This is accomplished by combining two methods. These methods are reasonable when used separately, but only reach their full potential when used together. First, mapping the dwell time (duration of stay) probability distribution to the travel time probability distribution lets zones become obsolete. Efforts to plan and calculate zones can be avoided and the inevitable imprecision when mapping to zones vanishes. Any deviation from the optimal storage location now results from errors in estimation. Second, dwell times must be based on unit loads which is the correct application of the cube-per-order-criterion for optimality. Without the need to use zones this does not result in extra effort to apply the strategy. For a part of the assortment the estimation of unit load dwell times is simpler than before too, making unit load dwell times even more appealing. However, even when using conventional article based dwell time estimates the strategy "Dynamic Zoning" results in higher performance than other strategies.

An important aspect during the planning of commuter trains is how long they will be waiting at the platform. All travelers must be able to board and get off the train in time while the process cannot take too long. The train’s waiting time is called its dwell time, and this is a study of how the dwell time of the commuter trains in Stockholm behaves with a focus on the larger station Stockholm Odenplan and the smaller station Årstaberg. The duration of the dwell time compared to the stations planned dwell time was analyzed with manual measurements on the stations. The dwell time was analyzed both during and after rush hours. Possible reasons for the dwell time’s length were also analyzed and a potential factor that was in focus was the impact of the removal of train conductors. Train conductors in Stockholm’s rail system are responsible for monitoring the boarding and closing the train’s doors after it is finished. They began to dismantle from the trains Mars 2023 due to efficiency reasons. Half of the trains will run with a train conductor until autumn 2023, where they will disappear entirely. The train drivers will afterwards monitor the travelers with cameras instead. The commuter trains in Stockholm have three routes between Bålsta and Nynäshamn, Uppsala/Märsta and Södertälje and Södertälje and Gnesta. Factors considered when planning their timetables are the system’s capacity, how long the train should wait at a station and how long it takes to drive between stations. 94 % of the trains run on time in the system according to the operator MTR. The analyzed stations Stockholm Odenplan and Årstaberg are in Stockholm and have their separate conditions. Stockholm Odenplan is the second to largest station in the system and is in a central part of the city. The station is underground, and the rails are separated from the platform with platform doors. The doors are shown to cause delays for the dwell time as they are slow. Årstaberg has considerably fewer travelers than Stockholm Odenplan and is in the south parts of the city. The station is over the ground and has no platform doors. There are many theories about the causes behind a train’s dwell time based on the behavior of the passengers. They vary from where they are waiting on the platform, how they are queueing during boarding and the behavior during the boarding. The study shows that the dwell time in Årstaberg stays under its planned 42 seconds, but it is six seconds too long from its planned 60 seconds in Stockholm Odenplan. The dwell time increases during rush hour in Årstaberg and decreases outside of it, while Stockholm Odenplan seems to be largely unaffected by rush hours. Trains with train conductors seem to have a lower dwell time than those without them. The boarding has a shorter duration with train conductors, which shows that they are more efficient than the train drivers using cameras to monitor the boarding. However, it does take a little longer for the train to depart after the boarding is finished when they have a train conductor. Factors causing the dwell time are believed to be related to the flow of passengers and the design of the stations. The platform doors are believed to increase the dwell time in Stockholm Odenplan. Meanwhile, the protection from the weather and the location of the entrance in Årstaberg might impact its dwell time. When the number of passengers increases will the boarding take longer. The boarding will also be concentrated on a few doors in Årstaberg depending on the weather or if the trains are short. The dwell time should be analyzed further for a longer period and during more hours of the day. More stations in Stockholm’s rail system should be analyzed too.

GKN Aerospace AB, Sweden (GAS) is one of the leading companies taking up the charge in manufacturing components using Additive Manufacturing(ed) (AM) techniques in the aerospace sector. They are a hub of engineering and they are a supplier of engine and engine components to the world’s leading aero-engine manufacturers, and airframes to civil and military aircraft manufacturers. A phenomenon that is of interest to designers at GAS is the effects of dwell times on high temperature fatigue, especially how this phenomenon affects the fatigue properties of Laser Powder Bed Fusion (LPBF) Inconel 718 (IN718). IN718 is a versatile alloy that can be used at relatively high temperatures and has excellent weldability and is one of the newer materials replacing expensive materials such as Titanium (and its alloys) in the aerospace industry. The aerospace industry has been pushing for an increase in parts manufactured using AM processes because of the advantage the AM process grants to the production process, however a new manufacturing process for an industry needs to be studied and researched from a failure perspective, i.e. the prominent mode of failure for components manufactured using AM and the underlying factors influencing the failure mechanism must be studied. This thesis explores a solution to predict the life of components based on experimental crack propagation tests wherein the test specimens were subjected to the phenomenon mentioned above. A literature survey was conducted researching ways to model this phenomenon and the factors affecting it. The methods found in the literature survey were far too complex to model for the purposes of this thesis, additionally the methods described in the literature were empirical methods describing the phenomenon, rather than a fundamental study of factors causing the phenomenon and ways to model their influence on the life of the component. Hence, a simple method based on the Palmgren-Miner linear damage summation rule which was coded in the form of a FORTRAN code was utilized to compute the life of the components. Software runs predicting life of physical experiments were conducted and inferences about the predictive method were drawn. The limitations of this method were understood and possible solutions were explored, based on which conclusions were drawn regarding the method’s efficacy in predicting the life of the specimens that underwent dwell loading during fatigue cycling. Finally, the method was applied to a case study to understand the effectiveness of the method. / GKN Aerospace AB, Sverige (GAS) är ett av de ledande företagen som tar upp kampen vid tillverkning av komponenter med hjälp av additiv tillverkning (AM) inom flyg- och rymdsektorn. De är ett nav för ingenjörskonst och de är en leverantör av motorer och motorkomponenter till världens ledande tillverkare av flygmotorer, och civila och militära flygplanstillverkare. Ett fenomen som är av intresse för designers på GAS är effekterna av uppehållstider på högtemperaturutmattning, särskilt hur detta fenomen påverkar utmattningen egenskaper hos Laser Powder Bed Fusion (LPBF) Inconel 718 (IN718). IN718 är en mångsidig legering som kan användas vid relativt höga temperaturer och har utmärkt svetsbarhet och är ett av de nyare materialen som ersätter dyra material såsom titan (och dess legeringar) inom flygindustrin. Flygindustrin har drivit på för en ökning av delar som tillverkas med additiva tillverkningsprocesser på grund av den fördel som tillverkningsprocessen ger en ny tillverkningsprocess för en industri behöver dock studeras och forskat ur ett misslyckandeperspektiv, dvs. det framträdande sättet att misslyckas för komponenter som tillverkats med hjälp av additiv tillverkning och de bakomliggande faktorer som mekanismen måste studeras. Denna avhandling utforskar en lösning för att förutsäga livslängden för komponenter baserat på experimentella sprickutbredningstester där provexemplaren utsattes för fenomenet som nämns ovan. En litteraturstudie genomfördes för att undersöka olika sätt att modellera detta fenomenet och de faktorer som påverkar det. Metoderna som framkom i litteraturstudien var alldeles för komplexa för att modellera för denna avhandling, dessutom är metoderna som beskrivits i litteraturen var empiriska metoder som beskriver fenomenet, snarare än en grundläggande studie av de faktorer som orsakar fenomenet och sätt att modellera deras inverkan på komponentens livslängd. Därav en enkel metod baserad på Palmgren-Miners linjära skadesummeringsregel som kodades i form av en FORTRAN-kod användes för att beräkna livslängden för komponenterna. Programvarukörningar som förutspådde livslängden för fysiska experiment genomfördes och slutsatser om den prediktiva metoden drogs. Begränsningarna med denna metod förstods och möjliga lösningar utforskades. Som låg till grund för de slutsatser som drogs om metodens effektivitet när det gäller att förutsäga livslängden för de prover som genomgick uppehållsbelastning underutmattningscykling. Slutligen tillämpades metoden på en fallstudie för att förstå effektiviteten avmetod.

In this paper, an investigation of the impact of menu design and input device for gaze-based menu selection tasks is reported. The study investigates the usability, measured by effectiveness, efficiency, and user satisfaction, for gaze-based interaction in realistic, complex menu selection tasks. The study includes three different menu designs, a linear drop-down menu (L1), a radial dynamic menu (R1), and a semi-radial menu (R2), along with two different input devices, a unimodal input device using dwell-time (DT) and a multimodal input device using a combination of gaze and a manual switch (GMS). In a user study with nine test participants, the impact of menu design, input device, and navigation complexity on task completion time, accuracy rate, cognitive load, and quality of use ratings for menu selection tasks were investigated. The usability results confirmed the expectations of the advantages of radial menu designs, with the radial dynamic menu (R1) being better suited for gaze- based interaction than either the linear drop-down menu (L1) or semi-radial menu (R2). The usability results also confirmed the expectations regarding the input device, namely, the multimodal GMS input device was superior to the unimodal DT input device for gaze-based interaction. / I den här studien rapporteras en undersökning av effekterna av menydesign och inmatningsenhet för blickbaserade menyvalsuppgifter. Studien undersöker användbarheten, mätt av verkningsgrad, effektivitet, och användarnöjdhet, för blickbaserad interaktion i realistiska, komplexa menyvalsuppgifter. Studien innefattar tre olika menydesigner, en linjär rullgardinsmeny (L1), en radiell dynamisk meny (R1) och en halvradiell meny (R2), tillsammans med två olika inmatningsenheter, en unimodal inmatningsenhet som använder dwell-time (DT) och en multimodal inmatningsenhet som använder en kombination av blick och en manuell knapp (GMS). I en användarstudie med nio testdeltagare undersöktes effekterna av menydesign, inmatningsenhet och navigeringskomplexitet på tiden för uppgifts slutförandet, noggrannhet, kognitiv belastning och kvalitet på användningsbetyg för menyvalsuppgifter. Användbarhetsresultaten bekräftade förväntningarna om fördelarna med radiella menydesigner, varvid den radiella dynamiska menyn (R1) passar bättre för blickbaserad interaktion än både den linjära rullgardinsmenyn (L1) eller halvradialmenyn (R2). Användbarhetsresultaten bekräftade också förväntningarna avseende inmatningsenheten, nämligen att multimodal GMS-inmatningsenheten var överlägsen den unimodala DT-inmatningsenheten för blickbaserad interaktion.

Les multiples applications liées aux systèmes multi-agents en réseau, tels que les satellites en formation, les oscillateurs couplés, les véhicules aériens sans pilote, entre autres, ont été, sans aucun doute, une motivation majeure dans le développement de cette thèse, qui est consacrée à l’étude du consensus de systèmes dynamiques et à la commande en formation de robots mobiles non holonomes. Dans le contexte du consensus, nous étudions la topologie en anneau avec de liens de communication variant dans le temps. Notamment, la communication peut être perdue pendant de longs intervalles de temps. Nous donnons de conditions suffisantes pour le consensus qui restent simples à vérifier, par exemple, en utilisant le théorème du petite gain. En suite, nous abordons le problème de consensus en supposant que la topologie de communication est variable. Nous établissons que le consensus est atteint à condition qu’il existe toujours un chemin de communication du type « spanning-tree » pendant un temps de séjour minimal. L'analyse s'appuie sur la théorie de stabilité des systèmes variant dans le temps et les systèmes à commutation. Dans le contexte de la commande en formation de véhicules autonomes nous adressons le problème de commande en suivi de trajectoire sur ligne droite en suivant une approche type maître-esclave. Nous montrons que le suivi global peut être obtenu à partir d’un contrôleur qui possède la propriété d’excitation persistante. En gros, le mécanisme de stabilisation dépend de l’excitation du système par une quantité qui est proportionnelle à l’erreur de suivi. Ensuite, la méthode est utilisée pour résoudre le problème de suivi de formation de plusieurs véhicules interconnectés sur la base d’une topologie « spanning-tree ». Nous donnons des conditions de stabilité concernant les modèles cinématique et dynamique, en utilisant la seconde méthode de Lyapunov. / The multiple applications related to networked multi-agent systems such as satellite formation flying, coupled oscillators, air traffic control, unmanned air vehicles, cooperative transport, among others, has been undoubtedly a watershed for the development of this thesis. The study of cooperative control of multi-agent systems is of great interest for his extensive field work and applications. This thesis is devoted to the study of consensus seeking of multi-agents systems and trajectory tracking of nonholonomic mobile robots.In the context of consensus seeking, first we study a ring topology of dynamic agents with time-dependent communication links which may disconnect for long intervals of time. Simple checkable conditions are obtained by using small-gain theorem to guarantee the achievement of consensus. Then, we deal with a network of dynamic agents with time-dependent communication links interconnected over a time-varying topology. We establish that consensus is reached provided that there always exists a « spanning-tree » for a minimal dwell-time by using stability theory of time-varying and switched systems. In the context of trajectory tracking, we investigate a simple leader-follower tracking controller for autonomous vehicles following straight lines. We show that global tracking may be achieved by a controller which has a property of persistency of excitation tailored for nonlinear systems. Roughly speaking the stabilisation mechanism relies on exciting the system by an amount that is proportional to the tracking error. Moreover, the method is used to solve the problem of formation tracking of multiple vehicles interconnected on the basis of a « spanning-tree » topology. We derive stability conditions for the kinematic and dynamic model by using a Lyapunov approach.

Les travaux de cette thèse portent sur l’analyse de stabilité et la synthèse de commande pour les systèmes singulièrement perturbés. Dans une première partie, nous présentons et analysons une classe générale de systèmes linéaires hybrides singulièrement perturbés dans lesquels la nature lente et rapide des variables d’état dépend du mode de fonctionnement. L’analyse de stabilité est fondée sur des résultats classiques de la théorie de Lyapunov pour les systèmes singulièrement perturbés. Une deuxième partie de ce travail présente la conception d’une loi de commande décentralisée qui garantit la synchronisation des systèmes multi-agents singulièrement perturbés avec un coût global garanti. Afin de contourner l’utilisation d’informations centralisées liées à la structure du réseau d’interconnexion, le problème est résolu en reformulant le problème de synchronisation comme un problème de stabilisation d’un système linéaire incertain singulièrement perturbé / This PhD thesis is dedicated to the study of stability and control design for singularly perturbed systems. In the first part, we introduce and analyze a general class of singularly perturbed linear hybrid systems, in which the slow or fast nature of the variables is mode-dependent. Our stability analysis is based on classical results of Lyapunov’s theory for singularly perturbed systems. A second part of this work presents the design of a decentralized control strategy that allows singularly perturbed multi-agent systems to achieve synchronization with global performance guarantees. To avoid the use of centralized information related to the interconnection network structure, the problem is solved by rewriting the synchronization problem in terms of stabilization of a singularly perturbed uncertain linear system

No description available.

La croissance de la taille des porte-conteneurs et leur déploiement sur les grandes routes maritimes mondiales est une réalité. Actuellement, la croissance de la capacité des porte-conteneurs a atteint 21 413 EVP, et les carnets de commandes laissent présager une tendance vers des navires encore plus grands. Par exemple, le transporteur CMA CGM devrait recevoir neuf nouveaux porte-conteneurs de 23 000 EVP d'ici la fin de l’année 2020. L’objectif de ce mémoire est de caractériser le mouvement des méga porte-conteneurs sur plusieurs routes maritimes, avec différents transporteurs et régions du monde. Cet objectif comporte deux volets; le premier porte sur l’analyse de la variabilité du temps des escales de méga-navires dans les ports, et le deuxième fait l’étude de la planification des routes de méga-navires pour les transporteurs maritimes. Les données historiques du mouvement d'un grand échantillon de méga-navires ont été analysées en vue de répondre à une série de questions permettant de structurer la recherche. Cette dernière permettra entre autres d’identifier les ports recevant des escales de méga-navires, d’évaluer la variabilité des temps d’escale ainsi que de présenter l’architecture des routes maritimes de ce type de navires. Enfin, cette étude permet de différencier la productivité des ports d'escale, des régions du monde et des transporteurs sur plusieurs routes maritimes. / The growth in the size of container vessels and their deployment is a reality. Currently, the growth of container ships is at 21 413 TEUs, and the order books for ever larger vessels portend an even greater trend towards larger vessels. For instance, CMA CGM will be delivered nine new 23 000 TEU container ships by the end of 2020. The objective of this paper is to characterize the movement of ultra-large container vessels (ULCV) on several shipping routes, with different carriers and regions of the world. This objective is two-fold; the first part deals with the variability of the dwell time of ULCV in the ports, and the second deals with the planning of ULCV routes for each maritime carrier. Historical data of the movement of a large sample of ULCV was analysed with a view to address a series of key issues. Here are some of these issues: What are the mains ports of call? What is the variability of dwell time between the ports of call? What are the routing patterns of mega containers vessels? This study will allow us to differentiate productivity of different ports of call, regions and shipping carriers on many shipping lanes.