As autonomous vehicle (AV) technology evolves and matures, automated public transit (APT) is gaining attention due to its flexibility, cost-effectiveness, and efficiency. This report explores various algorithms for allocating vehicles to passengers within APT systems. It aims to organize and propose effective allocation strategies and validate them through comparative analyses on test networks. Overall, the paper introduces several algorithms, with six specifically compiled and tested using the VIPSim simulator across four traffic networks. Two of these networks are basic, while the other two are more complex and represent real-world scenarios. Through these numerical experiments, the algorithm that maximizes network operational efficiency was identified, and several instructive conclusions were drawn from the comparative analysis.

<p dir="ltr">Ride-hailing is the frontier of transportation innovations and has become an essential component of urban mobility. Addressing the efficiency of service operations and associated challenges has significant implications for the future of transportation systems. </p><p dir="ltr">In this dissertation, we develop a series of approaches and tools to enhance the efficiency of ride-hailing systems, validate operational controls, and assess the associated risks. Through extensive numerical experiments, we demonstrate the efficacy of our methods.</p><p dir="ltr">In Chapter 2 to 4, we develop three complementary operational algorithms aimed at improving ride-hailing services' efficiency:</p><ul><li> Chapter 2 focuses on proactive vehicle repositioning using a supervised learning model to recommend optimal pickup locations for vacant vehicles. The numerical experiments suggest this strategy can reduce empty vehicle mileage and also balance driver income/utilization.</li><li>Chapter 3 presents a hub-based ride-sharing algorithm that features an efficient data structure for querying feasible vehicle schedules and employs model predictive control to account for future demand and supply uncertainties. This approach significantly outperforms baselines that do not account for future supply and demand or rely on point-wise predictions.</li><li>Chapter 4 addresses dynamic pricing in ride-hailing systems. We contribute to a rigorous definition of the problem and a reinforcement learning-based method to generate deterministic pricing policies. The numerical results suggest our approach can achieve near-optimal performance in promoting service income by effectively reducing empty vehicle mileage.</li></ul><p dir="ltr">Chapter 5 introduces METS-R SIM, an agent-based simulator that combines detailed microscopic traffic simulation models with dynamic demand-supply matching. We validate METS-R SIM against actual ride-hailing data, demonstrating its ability to accurately reproduce travel time and distance profiles and provide valuable insights for improving supply design and control strategies.</p><p dir="ltr">Finally, Chapter 6 explores the security challenges in autonomous mobility-on-demand (AMoD) systems. We develop a threat model to assess risks in the passenger-vehicle matching mechanism. Our experiments reveal that optimization-based attacks can significantly degrade service quality and increase traffic congestion, highlighting the need for extensive security analyses in autonomous ride-hailing operations.</p><p>Together, these contribute to a complete framework for improving ride-hailing systems with advanced operational algorithms, high-fidelity validation, and comprehensive risk assessments, paving the path toward a more efficient and secure ride-hailing service.</p>

The introduction of Distributed Energy Resources such as energy storage systems, solar, and wind create system dynamics which modern electric grids cannot reliably handle in such large quantities without properly coordinated protections. One such tool is the concept of Fault Ride Through, which allows a system to continue operation during a long-term minor or short-term major disturbance. Standards are in place to control and monitor the operation and recovery of this capability but are meant to be minimum or maximum requirements. Since these standards must be used nationally, or sometimes internationally, they tend to be left very flexible. The rise of inverter-based devices, however, means that stricter standards which provide better grid protections can be more easily achieved. This thesis presents a comprehensive review of the inverter requirements inside IEEE 1547 regarding Voltage Fault Ride Through, power quality, and recovery of these devices during fault conditions. It examines the technical requirements, discusses various techniques of implementation, and compares IEEE 1547 to other national and international standards. Several real-world case studies are included to highlight the consequences of inadequate Fault Ride Through protocols, emphasizing the importance of robust inverter design and proper controller settings.

Les rides de Barracuda et de Tiburon sont deux reliefs sous-marins situés dans la partie ouest de l'océan Atlantique, là où la lithosphère océanique des plaques Amérique du Nord (NAM) et Amérique du Sud (SAM) est entraînée par subduction sous la plaque Caraïbe, formant l'arc volcanique des Petites Antilles et le prisme d’accrétion de Barbade. Le processus et la période de soulèvement conduisant au relief actuel de ces rides (qui semblent être un marqueur important dans l'histoire géodynamique de la région) sont sujets à débat depuis des décennies.L’interprétation de nouvelles données de sismique réflexion et de bathymétrie multifaisceaux acquises à travers les rides de Barracuda et de Tiburon (campagne Antiplac, 2007 ) a permis de dater les périodes de soulèvements des rides et réaliser des reconstructions paléogéographiques incluant les flux sédimentaires majeurs, depuis le Crétacé jusqu’ à l’Actuel.L’analyse structurale révèle des phases de réactivations tardives d’anciennes zones de fractures dans un contexte transpressif, conduisant aux surrections des rides de Tiburon et de Barracuda.Les processus géologiques possibles impliqués dans la formation des rides de Barracuda et de Tiburon coïncident avec les modèles cinématiques récents décrivant les mouvements relatifs entre les plaques NAM et SAM, le long de la limite de plaque diffuse.Ces résultats permettent de mieux définir la limite de plaque entre NAM et SAM. Elle est nécessairement hétérogène exploitant les zones de faiblesses dans la lithosphère que sont les zones de fracture. Au sein de cette limite de plaque la lithosphère serait donc fragmentée. / The Barracuda Ridge and the Tiburon Rise, two oceanic-basement ridges, lie in the western Atlantic Ocean, where oceanic lithosphere of the North American (NAM) and South American (SAM) plates is subducted beneath the Caribbean plate, creating the Lesser Antilles volcanic arc and the Barbados Ridge accretionary complex. The process and the timing of the uplift leading to the present day morphologies of the Tiburon and Barracuda ridges, that seem to be key markers in the geodynamic history of the region, has remained a matter of debate for decades.From the analysis of new multibeam and seismic reflection profiles acquired in 2007 (Antiplac crusie) DSDP-ODP boreholes available, we provide new information on the timing of the formation of the Barracuda Ridge and Tiburon Rise in their present-day configurations. We propose paleogeographic reconstructions with the main sediments fluxes deposited in the area of the Barracuda and Tiburon ridges from the Late Cretaceous to present. Structural analysis shows reactivation of fracture zones in a transpressive setting leading to the uplifts of the Barracuda and Tiburon Ridges.The location of the Barracuda Ridge and the Tiburon Rise and the timing of the uplift fit well with recent global plate kinematic models describing the movements of NAM relative to SAM along a diffuse plate boundaryThis NAM-SAM plate boundary zone, therefore must most certainly be heterogeneous in nature, exploiting weaknesses in the lithosphere provided by fracture zones where mechanically advantageous, but forming new boundary segments elsewhere, to transfer motion between reactivated segments of the fracture zones.

O tema do conforto na automobilística é bastante extenso e possuidor de muitas interpretações. A ideia central deste trabalho é definir e direcionar alguns métricos para que, durante as fases de conceituação e desenvolvimento de um veículo, seja possível ter um direcional de definição de componentes e atributos veiculares de modo a facilitar o direcionamento dos atributos no programa veicular, e assim atingir suas necessidades. Como exemplo empregado, é empregado um veículo de plataforma tipo B em desenvolvimento por uma montadora, o qual teve as molas de suspensão definidas e rigidezes laterais de eixos com base em material técnico interno equivalente aos estudos apresentados neste trabalho. É adotada uma abordagem inicialmente empírica conforme os primeiros estudos de suspensões independentes realizados neste continente, depois o trabalho é complementado com exigências de normas especificas para vibrações (ISO2361, ISO5008, BS6055) de modo a caracterizar energia vibracional e a interpretação pelo ser humano. Porém como hoje em dia as suspensões automotivas são muito mais complexas, existem componentes específicos para as várias condições de solicitação, deste modo a análise é limitada a situações de ride (conforto) primário e handling (dirigibilidade) em situações de sublimite na faixa linear (cerca de 0,5 g). Como conclusão dos estudos, é possível ter em um veículo atributos de estabilidade sem necessariamente prejudicar o conforto, pois sendo definidos corretamente os componentes elásticos da dinâmica vertical para situações estacionárias e de ride primário, é definido seu equilíbrio estacionário e assim não é necessário comprometimento dos atributos de outros componentes para compensar alguma deficiência existente. / The range of assumptions for ride comfort is considered very wide in the automotive world and they can assume lots of possible interpretations. The central idea in this work is define and manage some metrics that, during the concept and development phases of a vehicular program, be possible to follow a better direction for the attributes development and so reach the program targets. As the example in this work, a B platform typical vehicle is used and it is under development in a carmaker, its suspension springs and axle roll stiffness were setup with technical information similar to the ones presented in this work. The initial approach is empiric as occurred with the first independent suspension system studies in this continent and in the sequence, the work is complemented with standards for vibrational issues (ISO2361, ISO5008, BS6055), after this, finally how the vibrational energy is defined and perceived by human beings. The automotive suspensions of current days are very complex and there are lots of specific components to do a specific work, so the analysis are limited to primary ride and sub limit handling (up to 0,5 g). As conclusion, its possible setup a car that is comfortable and stable in the same time, since the elastic components for the vertical dynamics and steady state conditions are correctly set, so its correct balance is reached and no other components attributes are compromised to compensate any deficiency.

Due to the detrimental effects of ride vibrations on occupants and increasing safety concerns, improvement in vehicle dynamic characteristics has become a key focus of researchers. Typically, ride and handling problems have been dealt with independently. There is a dearth of vehicle models capable of capturing occupant biodynamics and its implication on vehicle ride and handling. Also in general, the objective of conventional control systems has been to attenuate vertical dynamic response of the sprung mass of a vehicle. Feedback control based algorithms are predominantly used in active/semi-active suspensions that ignore the biodynamics of occupants. In the current work, a new 50 degree-of-freedom (DOF) combined nonlinear multi-occupant vehicle model is developed using the lumped parameter modelling (LPM) approach. The current model provides a platform for performing a combined study of ride, handling and occupant biodynamics. The model is capable of simulating the combined effect of sitting occupancies, road inputs and driving maneuvers on biodynamic responses. It is analyzed using MATLAB/SIMULINK functionalities and validated by independently correlating the computed responses with existing experimental results. A study is performed on ride behavior of a vehicle-occupant system under two different transient road inputs. In addition, the effect of road roughness on vehicle ride is also studied. Random road profiles are generated from road roughness spectrum given in the ISO 8608:1995 manual. Insights are developed into the ride dynamics of a vehicle traversing over roads of classes A, B, C and D at given test velocities. The effect of sitting occupancies and vehicle velocities on lateral dynamics is also studied. Results underscore the need for considering sitting occupancies while analyzing vehicle dynamics and also highlight the potential of the current model. Furthermore, a Moore-Penrose Pseudoinverse based feed-forward controller is developed and implemented in an independently acting semi-active seat suspension system. Feasibility of feed-forward control in primary suspensions is also investigated. Finally, issues of stability, performance and limitation of the controller are discussed.

O tema do conforto na automobilística é bastante extenso e possuidor de muitas interpretações. A ideia central deste trabalho é definir e direcionar alguns métricos para que, durante as fases de conceituação e desenvolvimento de um veículo, seja possível ter um direcional de definição de componentes e atributos veiculares de modo a facilitar o direcionamento dos atributos no programa veicular, e assim atingir suas necessidades. Como exemplo empregado, é empregado um veículo de plataforma tipo B em desenvolvimento por uma montadora, o qual teve as molas de suspensão definidas e rigidezes laterais de eixos com base em material técnico interno equivalente aos estudos apresentados neste trabalho. É adotada uma abordagem inicialmente empírica conforme os primeiros estudos de suspensões independentes realizados neste continente, depois o trabalho é complementado com exigências de normas especificas para vibrações (ISO2361, ISO5008, BS6055) de modo a caracterizar energia vibracional e a interpretação pelo ser humano. Porém como hoje em dia as suspensões automotivas são muito mais complexas, existem componentes específicos para as várias condições de solicitação, deste modo a análise é limitada a situações de ride (conforto) primário e handling (dirigibilidade) em situações de sublimite na faixa linear (cerca de 0,5 g). Como conclusão dos estudos, é possível ter em um veículo atributos de estabilidade sem necessariamente prejudicar o conforto, pois sendo definidos corretamente os componentes elásticos da dinâmica vertical para situações estacionárias e de ride primário, é definido seu equilíbrio estacionário e assim não é necessário comprometimento dos atributos de outros componentes para compensar alguma deficiência existente. / The range of assumptions for ride comfort is considered very wide in the automotive world and they can assume lots of possible interpretations. The central idea in this work is define and manage some metrics that, during the concept and development phases of a vehicular program, be possible to follow a better direction for the attributes development and so reach the program targets. As the example in this work, a B platform typical vehicle is used and it is under development in a carmaker, its suspension springs and axle roll stiffness were setup with technical information similar to the ones presented in this work. The initial approach is empiric as occurred with the first independent suspension system studies in this continent and in the sequence, the work is complemented with standards for vibrational issues (ISO2361, ISO5008, BS6055), after this, finally how the vibrational energy is defined and perceived by human beings. The automotive suspensions of current days are very complex and there are lots of specific components to do a specific work, so the analysis are limited to primary ride and sub limit handling (up to 0,5 g). As conclusion, its possible setup a car that is comfortable and stable in the same time, since the elastic components for the vertical dynamics and steady state conditions are correctly set, so its correct balance is reached and no other components attributes are compromised to compensate any deficiency.

Disertacijoje atliekama automobilių stovėjimo vietų poreikio mieste analizė. Pagrindinis darbo objektas – asmeninių kelionių automobilių stovėjimo vietų didmiestyje pasiskirstymo sistema. Ekspertiniu metodu sudaryta automobilių stovėjimo vietų mieste kriterijų sistema. Taikant daugiatikslius metodus kriterijams suteikti rangai ir apskaičiuoti jų svorių koeficientai, kurie leido nustatyti kriterijų prioritetus ir parinkti racionaliausias automobilių stovėjimo aikštelių išdėstymo vietas miesto teritorijoje. Pagrindinis darbo tikslas – pasiūlyti automobilių stovėjimo vietų mieste plėtros vertinimo modelį ir pateikti originalius automobilių stovėjimo aikštelių plėtros koncepcinius sprendinius. Disertaciją sudaro įvadas, 3 skyriai, bendrosios išvados, literatūros sąrašas, publikacijų sąrašas. Įvade trumpai aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimo objektas, formuluojamas darbo tikslas ir uždaviniai, aprašoma mokslinis darbo naujumas, ginamieji teiginiai. Įvado pabaigoje pristatomos autoriaus paskelbtos publikacijos, pranešimai konferencijose, nurodomas dalyvavimas tarptautiniuose seminaruose ir pateikiama disertacijos struktūra. Pirmame skyriuje pateikiama mokslinės literatūros ir kitų atliktų darbų analizė nagrinėjama tematika. Taip pat atlikta Lietuvos Respublikos, Europos Sąjungos ir kitų pasaulio šalių norminių dokumentų, reglamentuojančių lengvųjų automobilių stovėjimą skirtingose miesto teritorijose, analizė. Antrajame skyriuje atliekamas automobilių... [toliau žr. visą tekstą] / This dissertation examines the shortage of motor vehicle parking spaces in the city area. The object of this research is the allocation of passenger car parking spaces in cities. A criteria system for car parking spaces in cities was formed using the expert estimate method. By using multi-criteria methods, the criteria were grouped and their factor value was calculated, which helped to establish the priorities of the criteria and to determine the most rational places for parking lots in the city area. This research aims to suggest a model for developing an infrastructure of car parking spaces in the city and to present original conceptual solutions for the expansion of parking lots. The dissertation comprises an introduction, three chapters, general conclusions, a list of literature, and a list of publications. The introduction specifies the problem, describes the relevance of the paper, names the research object, the aim and objectives, its scientific novelty, and the defended statements. Finally, it lists publications and conference presentations of the author, describes the author’s participation in international seminars and presents the structure of the dissertation. Chapter one introduces the literature overview of the subject analysis and discusses the study of the scientific research carried out in this field. It also presents the examination of the normative documents in Lithuania, the European Union and in other countries, which regulate motor car parking in... [to full text]

Pagrindinis magistro darbo tikslas – parengti „Statyk ir važiuok“ stovėjimo aikštelių įrengimo pagrindimo metodiką ir pateikti siūlymus dėl tokių stovėjimo aikštelių plėtros Vilniaus mieste. Darbo užduotys – atlikti literatūros šaltinių apžvalgą, išanalizuoti Vilniaus miesto specialiajame plane pateiktus „Statyk ir važiuok“ stovėjimo aikštelių įrengimo variantus, atlikti studentų bei ekspertų nuomonės tyrimus aikštelių įrengimo klausimais, nustatyti, kokios aikštelės yra tinkamiausios, pasitelkus statistinę skaičiavimo metodiką. Šiame darbe taikomi trys statistiniai metodai – SAW , TOPSIS ir COPRAS. Skaičiavimų metu, pagal tam tikrus parinktus kriterijus, apskaičiuojama, kurių iš siūlomų aikštelių įrengimas yra tikslingiausias. Studentų nuomonės tyrimo metu nustatytos devynios tinkamiausios aikštelės, o ekspertų nuomonės tyrimo metu nustatyta po tris tinkamiausias aikšteles periferinėje, vidurinėje ir centrinėje miesto zonose. Gauti tyrimų rezultatai gali būti panaudoti atsižvelgiant į tolesnę aikštelių plėtrą Vilniaus mieste. Darbo tekstine dalį turi sudaryti 78 p., 1–17 pav., 1–16 lent. ir 5 priedai, taip pat turi būti išanalizuoti 34 literatūros ir informacijos šaltiniai. Grafinę baigiamojo darbo dalį turi sudaryti 1 brėžinys: 1. Tinkamiausios „Statyk ir važiuok“ aikštelės Vilniaus mieste M 1:50 000. / The main aim of this masters work is to arrange „Park and ride“ parking spots installation method and to introduce proposals for parking spots development in Vilnius. The main assignment of this work is to analyze literature sources, to analyze "Park and Ride" sites which are listed in "Vilnius city special plan", to organize student and expert opinion survey about the "Park and Ride" sites development, to identify which of the sites are the best for Vilnius city, using multi-criteria analysis. In this job, three methods were used - SAW, TOPSIS and COPRAS. During the counting, several criteria are chosen to prove which site is the bests. In the student survey nine sites were declared as the most appropriate for the Vilnius. In the expert survey, there were three most appropriate sites in every region - periphery, middle city part and the center. The results of the survey can be used for further "Park and Ride" sites development in Vilnius. The work consists of the 78 pages of text, 17 figures 16 tables and 5 annexes as well as analysis of 34 literature and information sources. The graphical part of the thesis consists of 1 drawing: 1. The most appropriate “Park and Ride” sites for Vilnius M 1:50 000.

The topic of this PhD thesis is active suspension in rail vehicles whichis usually realized through sensors, controllers and actuation components.A well established example of an active suspension is the tiltingcontrol system used to tilt the carbody in curves to reduce centrifugalacceleration felt by passengers. Active suspension for rail vehicles is beingstudied since 1970s and in this PhD thesis it has been tried to expandon some aspects of this topic.This study extends the research field by both experimental and theoreticalstudies. In the first phase of the study which led to a licentiatedegree the focus was more on experimental work with active verticalsuspension (AVS). This was implemented by introducing actuators inthe secondary suspension of a Bombardier test train, Regina 250, in thevertical direction. The aim has been to improve vertical ride comfort bycontrolling bounce, pitch and roll motions.In the second phase after the licentiate, the studies have been moretheoretical and can be divided into two parts. The first part of the workhas been more focused on equipping two-axle rail vehicles with differentactive suspension solutions for improving the vehicle performanceregarding comfort and wheel-rail interaction. Three papers are writtenon active suspension for two-axle rail vehicles. Two of the papers discussthe use of H¥ control for wheelset guidance in curves to reducewheel-rail damage. The third paper shows that by use of active verticaland lateral suspension (AVS and ALS) in two-axle rail vehicles goodcomfort can be achieved as well. The paper then studies how the threeactive suspension systems (ALS, AVS, and ASW) interact once implementedtogether on a two-axle rail vehicle.The second part is a study on safety of active suspension systems.The study discusses a possible procedure to ensure that a designed activesuspension for a rail vehicle will be safe in all possible failure situations. / <p>QC 20170602</p>