Spelling suggestions: "subject:"astrain"" "subject:"1strain""
41 |
行政院人事行政局公務人員訓練班薦任人事人員專業訓練課程績效評估之研究 / Evaluation of the Professional Training Course conducted by the Personnel Bureau of the Executive Yuan for Officials in Goverment Personnel Departments余品嫺, Yu, Pin Hsien Unknown Date (has links)
針對現今大多數之訓練而言,評估的缺乏應可說是最普遍的缺失,訓練人員經常假定訓練方案有其價值而避免從事評估,或只著重受訓者對訓練之感受與經驗此種反應性評估,而對訓練內容本身並不加以檢視,原因即「訓練評估」的高困難度、冗長乏味及費時極長、有許多變項可能干擾評估的準確度、評估所得的結果也容易招致外在的批評或壓力、有時評估的結果也不一定使人信服...等,種種的困難均使得訓練人員傾向於訓練可以運作即可,而儘可能避免去從事此種吃力不討好的工作。雖然當前訓練評估存有不少的問題及阻礙,我仍嘗試以理論及實務觀點來對訓練評估問題作更進一步的探討,並以行政院人事行政局公務人員訓練班薦任人事人員為例來作進一步了解,期對訓練評估有更進一步研究並使評估問題能受訓練部門重視。
|
42 |
Influência do uso de trens de caixa móvel na implantação e operação de novas ferrovias. / Influence of the use of tilting trains on the implementation and operation of new railways.Felipe Rabay Lucas 16 March 2015 (has links)
O presente trabalho tem por objetivo primário abordar os atuais conhecimentos sobre o transporte ferroviário interurbano e regional de passageiros, com foco na tecnologia dos trens de caixa móvel, também conhecidos como trens pendulares. Como objetivo secundário busca-se analisar a influência dos trens de caixa móvel ou pendulares na implantação e operação de novas ferrovias, com ênfase na adequação em fase de projeto, mostrando-se o potencial dessa tecnologia para o aumento da velocidade média e a redução dos tempos de viagem. São tratados os tópicos relevantes para o transporte ferroviário de passageiros, como o conforto do usuário, as especificações técnicas do material rodante e referências dos custos de implantação e operação envolvidos, mostrando-se também dentro de cada aspecto as diferenças dos trens pendulares em relação aos trens convencionais. Três estudos de caso elaborados terão como objetivo explicitar as interveniências da operação dos trens pendulares com o projeto ferroviário, em especial com o projeto geométrico, e através de simulações de marcha e comparações, mostrar de maneira prática o potencial do uso dos trens pendulares. Através do embasamento teórico e dos estudos de caso, é feita uma análise crítica de modo a possibilitar tanto um entendimento do transporte ferroviário de passageiros, quanto do material rodante de caixa móvel e suas possibilidades. Os resultados dos estudos de caso e a análise crítica mostram uma redução significativa dos tempos de viagem, entre 8,1 e 20,0%, mediante a operação de trens pendulares em substituição ao material rodante convencional. / As a primary objective, the present work aims to summarize the current knowledge on intercity and regional passenger railway transportation, focusing on tilting train technology, also known as car body tilt. As a secondary objective, the present work seeks to analyze the influence of tilting train technology on the design, implementation and operation of new railway corridors, with emphasis on design phase, showing the potential of this technology to increase speeds and reduce travel times. Railway passenger transportation issues, such as passenger comfort, rolling stock technical specifications and implementation and operational costs are addressed. Additionally, different aspects between conventional and tilting trains are also discussed. Three case studies help clarify the correlation between tilting train operation and railway design, especially the geometric design; further, with the help of speed simulations and comparisons, the potential use of tilting train operations are demonstrated. With the theoretical basis and the case studies, a critical analysis is made, allowing as a better understanding of railway passenger transportation with regards to the use of tilting rolling stock and its possibilities. The results of the case studies and the critical analysis present a considerable reduction in travel times, between 8,1 and 20,0%, with the operation of tilting trains in the place of the conventional rolling stock.
|
43 |
Visual and Analytical Support for Real-time Evaluation of Railway Traffic Re-scheduling Alternatives During DisturbancesKarthikeyan, Arun Kumar, Mani, Praveen Kumar January 2012 (has links)
Disturbances in the railway network are frequent and to some extent, inevitable. When this happens, the traffic dispatchers need to re-schedule the train traffic and there is a need for decision support in this process. One purpose of such a decision support system would be to visualize the relevant, alternative re-scheduling solutions and benchmark them based on a set of relevant train traffic attributes which quantify the effects of each solution. Currently, there are two research projects financed by the Swedish Transport Administration (i.e. Trafikverket) which focus on developing decision support to assist the Swedish train traffic managers: The STEG project and the EOT project. Within the STEG project, researchers at Uppsala University in co-operation with Trafikverket are developing a graphical user interface (referred to as the STEG graph). Within the EOT project, researchers at Blekinge Institute of Technology (BTH) are developing fast re-scheduling algorithms to propose to the Swedish train traffic dispatchers a set of relevant re-scheduling alternatives when disturbances occur. However, neither the STEG graph nor the EOT algorithms are at this point designed to evaluate, benchmark and visualize the alternative re-scheduling solutions. The main objective of this work is therefore to identify and analyze different train traffic attributes and how to use the selected relevant ones for benchmarking re-scheduling solutions. This involves enhancing an existing visual tool (EOT GUI) and using this extended version (referred to as the EOT GUI+) to demonstrate and evaluate the benchmarking of different re-scheduling solutions based on the selected train traffic attributes. The train traffic attributes found in the literature (foremost research publications and documents by Trafikverket) were collected and analyzed. A subset of the most commonly used attributes found were then selected and their applicability in benchmarking re-scheduling solutions for the Swedish train traffic system was further analyzed. The formulas for calculating each of the attribute values were either found in the literature and possibly modified, or defined within this thesis project. In order to assess the use of the attributes for benchmark solutions, experiments were conducted using the enhanced visual tool EOT GUI+ and a set of sample solutions for three different disturbance scenarios provided by the EOT project. The tool only performs a benchmark of two solutions at a time (i.e. a pair wise benchmark) and computes the attribute values for the chosen attributes. The literature review and attribute analysis resulted in a first set of ten different attributes to use including e.g. total final delay (with a delay threshold value of 1 and 5 minutes respectively), maximum delay, total accumulated delay, total delay cost, number of delayed trains and robustness. The formulas to compute these attribute values were implemented and applied to the sample solutions in the experiments. The first phase of the experiments showed that in one of the disturbance scenarios, some of the attribute values were in conflict and that none of re-scheduling solution was dominating the others. This observation led to that the set of attributes needed to be narrowed down and internally prioritized. Based on the experimental results and the analysis of what the research community and the main stakeholder (i.e. Trafikverket) consider are the most important attributes in this context, the final set of attributes to use includes average final delay, maximum delay of a single train, total number of delayed trains and robustness. The contribution of this thesis is primarily the review and analysis of what attributes to use when performing a benchmark of re-scheduling solutions in real-time train traffic disturbance management. Furthermore, this thesis also contributes by performing an experimental assessment of how the attributes and their formulas could work in a pair-wise, quantitative benchmark for a set of disturbance scenarios and which issues that may occur due to conflicting objectives and attribute values. Concerning the enhancement of the visual tool and the visualization of the re-scheduling solutions, the experimental evaluation and analysis shows that the tool would not fit directly to the needs of the train dispatchers. This work should therefore only be seen as a starting point for the researchers whom are working with the development of decision support systems in this context. Furthermore, several iterative experiments have been conducted to select the appropriate attributes for benchmarking solutions and suggesting the best re-scheduling solution. During the experiments, we have used a limited set of different problem instances (2+2+7) representing three different types of disturbances. The performance of the enhanced visual tool EOT GUI+ and its functionalities should ideally also be analyzed further and improved by experimenting with a larger number of instances, for other parts of the Swedish railway network and in co-operation with the real users, i.e. the dispatchers.
|
44 |
Statistical inverse problem in nonlinear high-speed train dynamics / Problème statistique inverse en dynamique non-linéaire des trains à grande vitesseLebel, David 30 November 2018 (has links)
Ce travail de thèse traite du développement d'une méthode de télédiagnostique de l'état de santé des suspensions des trains à grande vitesse à partir de mesures de la réponse dynamique du train en circulation par des accéléromètres embarqués. Un train en circulation est un système dynamique dont l'excitation provient des irrégularités de la géométrie de la voie ferrée. Ses éléments de suspension jouent un rôle fondamental de sécurité et de confort. La réponse dynamique du train étant dépendante des caractéristiques mécaniques des éléments de suspension, il est possible d'obtenir en inverse des informations sur l'état de ces éléments à partir de mesures accélérométriques embarquées. Connaître l'état de santé réel des suspensions permettrait d'améliorer la maintenance des trains. D’un point de vue mathématique, la méthode de télédiagnostique proposée consiste à résoudre un problème statistique inverse. Elle s'appuie sur un modèle numérique de dynamique ferroviaire et prend en compte l'incertitude de modèle ainsi que les erreurs de mesures. Les paramètres mécaniques associés aux éléments de suspension sont identifiés par calibration Bayésienne à partir de mesures simultanées des entrées (les irrégularités de la géométrie de la voie) et sorties (la réponse dynamique du train) du système. La calibration Bayésienne classique implique le calcul de la fonction de vraisemblance à partir du modèle stochastique de réponse et des données expérimentales. Le modèle numérique étant numériquement coûteux d'une part, ses entrées et sorties étant fonctionnelles d'autre part, une méthode de calibration Bayésienne originale est proposée. Elle utilise un métamodèle par processus Gaussien de la fonction de vraisemblance. Cette thèse présente comment un métamodèle aléatoire peut être utilisé pour estimer la loi de probabilité des paramètres du modèle. La méthode proposée permet la prise en compte du nouveau type d'incertitude induit par l'utilisation d'un métamodèle. Cette prise en compte est nécessaire pour une estimation correcte de la précision de la calibration. La nouvelle méthode de calibration Bayésienne a été testée sur le cas applicatif ferroviaire, et a produit des résultats concluants. La validation a été faite par expériences numériques. Par ailleurs, l'évolution à long terme des paramètres mécaniques de suspensions a été étudiée à partir de mesures réelles de la réponse dynamique du train / The work presented here deals with the development of a health-state monitoring method for high-speed train suspensions using in-service measurements of the train dynamical response by embedded acceleration sensors. A rolling train is a dynamical system excited by the track-geometry irregularities. The suspension elements play a key role for the ride safety and comfort. The train dynamical response being dependent on the suspensions mechanical characteristics, information about the suspensions state can be inferred from acceleration measurements in the train by embedded sensors. This information about the actual suspensions state would allow for providing a more efficient train maintenance. Mathematically, the proposed monitoring solution consists in solving a statistical inverse problem. It is based on a train-dynamics computational model, and takes into account the model uncertainty and the measurement errors. A Bayesian calibration approach is adopted to identify the probability distribution of the mechanical parameters of the suspension elements from joint measurements of the system input (the track-geometry irregularities) and output (the train dynamical response).Classical Bayesian calibration implies the computation of the likelihood function using the stochastic model of the system output and experimental data. To cope with the fact that each run of the computational model is numerically expensive, and because of the functional nature of the system input and output, a novel Bayesian calibration method using a Gaussian-process surrogate model of the likelihood function is proposed. This thesis presents how such a random surrogate model can be used to estimate the probability distribution of the model parameters. The proposed method allows for taking into account the new type of uncertainty induced by the use of a surrogate model, which is necessary to correctly assess the calibration accuracy. The novel Bayesian calibration method has been tested on the railway application and has achieved conclusive results. Numerical experiments were used for validation. The long-term evolution of the suspension mechanical parameters has been studied using actual measurements of the train dynamical response
|
45 |
RFID for more effective and efficient train maintenance : A case study of a train depot in a deregulated market / RFID för en mer effektiv depåverksamhetHenningsson, Diana, Wendel, Olivia January 2019 (has links)
In this master thesis the potential value of using RFID technology in train depots has been investigated. Train depots are a crucial part of the railway system as safe and timely traffic relies on the maintenance activities preformed in them. The Swedish passenger train traffic is expected to increase significantly in the coming years and the ability to expand the existing train depots is limited. Optimal utilization of depots, achieved by efficient and effective operations, is therefore crucial. Coordinating the activities within depots is a complex activity due to the limited resources, inflexible infrastructure and the need for continuous monitoring due to unforeseen events. The complexity is further increased with the large number of independent actors. Due to EU-directives all member nations have to liberalize their passenger railway markets, enabling new actors to enter the market. Sweden's passenger railway market was fully deregulated in 2010. For this thesis a case study on one of the largest depots in Sweden has been conducted to examine how RFID technology can enhance the efficiency and effectiveness of its depot operations. The most important factors for achieving this is to facilitate an efficient flow of vehicles between service stations and efficient and accurate flow of communication between the many actors. Based on this, three key objectives were identified for achieving effective and efficient depot operations; communication, coordination and transparency. The benefits of RFID have been analyzed within the areas; asset tracking, maintenance and safety, and opportunities for achieving the key objectives were identified within each of these areas. The findings show that RFID enables for better utilization of resources, which allows more trains to use the depot. Also, cost savings can be captured by automating manual tasks. The effectiveness of the maintenance operations can be improved by elimination of non-value adding activities and the risk of mistakes due to the human factor. It was also discovered that the transparent data that RFID provides can improve stakeholder relations and that it could be used for identification of problem areas. Conclusively, the findings of the study show that effectiveness and efficiency of train depots can be improved with the use of RFID to meet the future demands of an increased passenger train traffic. / I den här uppsatsen har nyttan av att använda RFID i tågdepåer analyserats. Tågdepåer är en viktig del av järnvägssystemet då majoriteten av allt tågunderhåll sker där. Den svenska tågtrafiken förväntas att öka markant framöver men möjligheten att bygga ut de befintliga tågdepåerna är begränsad på grund av den knappa tillgången till mark i anslutning till depåerna. För att hantera den ökade tågtrafiken är det därför viktigt att verksamheten i depåer sker så effektivt som möjligt för att uppnå optimalt resursutnyttjande. Att koordinera flödet av fordon genom depån är en komplex uppgift på grund av de begränsade resurserna och den stela infrastrukturen. Ytterligare en faktor som bidrar till komplexiteten är det stora antalet aktörer som är verksamma i depån. Till följd av att den svenska tågmarknaden avreglerades så har antalet självständiga aktörer på marknaden ökat, vilket gör det svårt att samordna aktiviteterna inom depåer. I enlighet med rådande EU-direktiv kommer alla medlemsländer under de närmaste åren att avreglera sina marknader för persontåg, vilket tillåter nya aktörer att gå in på marknaden. I den här uppsatsen har en fallstudie av en av Sveriges största tågdepåer genomförts för att undersöka hur verksamheten inom depån kan effektiviseras med hjälp av RFID. För att uppnå en effektiv depåverksamhet är det viktigt att säkerställa effektiv kommunikation mellan aktörer och förflyttning av tåg. I enlighet med detta har tre nyckelfaktorer identifierats för att uppnå effektivitet i depån; koordination, kommunikation och transparens. Vidare har värdet av att implementera RFID analyserats inom tre områden; lokalisering av fordon, underhåll och säkerhet. Inom samtliga områden har möjligheter att uppnå de tre nyckelfaktorerna identifierats. Resultatet visar att kostnadsbesparingar kan uppnås genom bättre resursutnyttjande och automatisering av manuella uppgifter. Bättre resursutnyttjande gör det även möjligt för fler fordon att använda depåns faciliteter. Effektivitetsökningar kan uppnås genom att ickevärdeskapande aktiviteter elimineras och fel orsakade av den mänskliga faktorn reduceras. Resultatet visar även att relationerna mellan olika aktörer kan förbättras eftersom mer precis information delas, vilket kan förhindra uppkomsten av oenigheter. Datan från RFID kan också användas för att identifiera problemområden och ligga till underlag för analys av framtida projekt. Sammanfattningsvis visar resultatet av studien att effektiviteten i tågdepåer kan förbättras med hjälp av RFID för att kunna hantera en framtida ökning av tågtrafiken.
|
46 |
Architecture décisionnelle pour la conduite collaborative de véhicules autonomesFrenette, Patrick January 2010 (has links)
L'automobile est un moyen de transport de prédilection puisqu'elle confère beaucoup de liberté aux utilisateurs. Cependant, les coûts sociaux et économiques reliés aux accidents de la route, ainsi que les émissions polluantes produites par la combustion des hydrocarbures, représentent une problématique à laquelle le Réseau de centres d'excellence AUTO21 s'intéresse. Notamment, AUTO21 finance ce projet qui porte sur les architectures décisionnelles appliquées aux trains de véhicules. Un train de véhicule est un système de transport intelligent regroupant un ensemble de véhicules qui se suivent les uns derrière les autres, conservant une faible distance entre eux.L'architecture DCD est une architecture décisionnelle complète avec communication bidirectionnelle responsable de la prise de décision distribuée d'un groupe de véhicules opérant au sein d'un train de véhicules.L'architecture réalise la plupart des manoeuvres réalisables dans les trains de véhicules tels l'insertion ou le retrait d'un véhicule dans le train, ainsi que la gestion des situations d'urgences telles les collisions et la défaillance de certains capteurs. La validation de l'architecture est effectuée avec un groupe de quatre robots mobiles équipés d'un système de positionnement relatif qui permet de localiser les véhicules les uns par rapport aux autres. Un ensemble de 18 scénarios de tests, couvrant un large éventail des situations susceptibles de survenir dans les trains de véhicules, est réalisé. Les résultats obtenus indiquent que la prise de décision des véhicules, ainsi que la coordination des véhicules via la communication sont robustes et permettent l'exécution des manoeuvres attendues.
|
47 |
Ground borne vibrations from high speed trainsConnolly, David January 2013 (has links)
A consequence of high speed rail transportation is the generation of elevated ground borne vibrations. This thesis presents several original contributions towards the prediction of these vibrations. Firstly, a new three dimensional finite element model capable of vibration prediction was developed. Its main feature was its ability to model complex track geometries while doing so through a fully coupled vehicle-tracksoil system. Model output was compared to experimental results obtained during this thesis and also to independent data sets. It was shown to predict velocity time histories, vibration frequency spectrums and international vibration descriptors with high accuracy. An appraisal of the suitability of a finite difference time domain modelling approach for railway vibration prediction was also undertaken. This resulted in the development of a new ‘higher order’ perfectly matched layers absorbing boundary condition. This condition was found to offer higher performance in comparison to current alternative absorbing boundary conditions. Field work was then undertaken on high speed lines with varying embankment conditions in Belgium and England. Vibration data was recorded up to 100m from each track and geophysical investigations were performed to determine the underlying soil properties. The results were used for numerical model validation and also to provide new insights into the effect of various embankment conditions on vibration propagation. It was found that embankments generate higher frequency excitation in comparison to nonembankment cases and that cuttings generate higher vibration levels than noncuttings. Once validated the finite element model was used to provide new insights into the effect of train speed, embankment constituent materials and railway track type on vibration levels. It was found that the shape and magnitude of ground vibration increased rapidly as the train’s speed approached the Rayleigh wave speed of the underlying soil. It was also found that ballast, slab and metal tracks produced similar levels of vibration and that stiffer embankments reduced vibration levels at distances near and far from the track. Two vibration mitigation techniques were also explored through numerical simulation. Firstly, an analysis was undertaken to determine the ability of a new modified ballast material to actively isolate vibration within the track structure. Secondly, wave barrier geometries were investigated to optimise their performance whilst minimising cost. It was found that barrier depth was the most influential parameter, whereas width had little effect. Additionally, geometry optimisation was found to result in a 95% cost saving in comparison to a base case. Using a vast array of results generated using the previously developed finite element model, a new empirical prediction model was also developed, capable of quickly assessing vibration levels across large sections of track. Unlike currently available empirical models, it was able to account for soil properties in its calculation and could predict a variety of international vibration metrics. It was shown to offer increased prediction performance in comparison to an alternative empirical model.
|
48 |
Spain, the European Union and the United States in the age of terror Spanish strategic culture and the global war on terrorWilkes, Herman L. 06 1900 (has links)
Approved for public release; distribution is unlimited. / This thesis looks beyond the tragic events of 11 March 2004 to uncover the greater Spanish strategic culture that motivates and influences Spain's political elites. By examining the interaction between Spanish conservatives and liberals, discerning the Spanish strategic culture will allow for a greater understanding of the foreign policy implications to both the Spanish-US relationship and Spanish-EU integration after the Madrid bombings. By understanding how Spanish elites make decisions on the utilization of military force with respect to NATO operations and European Union security, this thesis first demonstrates the strategic preferences of the Spanish elites. Secondly, this thesis shows that the collective identity of Spanish elites seeks further influence in regional economic and global policy making. Lastly, this thesis reveals that Spain is in a unique position to develop a strong bilateral relationship with the US while furthering its integration with the EU but is unwilling to support the furthering of cooperation and integration at the expense of Spanish national interests. Uncovering the Spanish strategic culture will provide a possible generalization to whether this event will lead to a shift in the Spanish strategic culture or open a new chapter in the transatlantic relationship. This thesis suggests that the bombings will not redefine the strategic culture of Spain but reinforce Spain's commitment against international terrorism. / Major, United States Marine Corps
|
49 |
Energetic macroscopic representation and multi-level energy management for heavy-duty hybrid vehicles using double planetary geartrain / Représentation énergétique macroscopique et gestion de l'énergie multi-niveaux pour véhicules hybrides lourds en utilisant un double train épicycloïdalSyed, Sajjad Ali 06 June 2012 (has links)
Actuellement, les Véhicules Electriques Hybrides (VEHs) sont considérés comme une partie essentielle du futur de l'industrie automobile. En effet, cette technologie permet de réduire la consommation de carburant et les émissions de gaz à effet de serre et ce, sans réduire les performances. Les VEHs sont composées de deux ou plusieurs sources d'énergie. Ces sources peuvent être organisées selon plusieurs architectures. Dans cette thèse, l’architecture série-parallèle est choisie pour des véhicules types militaires et de collecte d’ordures. Les VEHs étudiés contiennent un double train planétaire. Ce nouveau répartiteur de puissance rend le système très complexe. Par conséquent, dans cette thèse, la modélisation des VEHs étudiés avec un double train planétaire est faite. L’utilisation de la Représentation Macroscopique Energétique (REM), représentation graphique permettant de déduire la structure de commande, est effectuée pour les deux véhicules étudiés. Cette thèse aborde également la problématique de la gestion de l'énergie des systèmes multi-sources pour les VEHs. Leur stratégie de gestion de l'énergie regroupe plusieurs disciplines et soulève différents challenges. Les défis résident principalement dans la gestion de la dépense d'énergie, la détermination de la répartition de l’énergie et l’établissement de méthode d'interface entre les différents systèmes de manière à répondre aux exigences de la propulsion et des autres exigences de la charge. Dans ce travail, une nouvelle organisation de la stratégie de gestion de l’énergie a été effectuée pour les véhicules étudiés (véhicules militaire et de collecte d’ordures) par une décomposition de cette gestion en 3 niveaux bien distincts. / Currently, Hybrid Electric Vehicles (HEVs) are considered to be a critical part of the future vehicle industry. This is because they allow for decreased fuel consumption and emissions without a decline in performance. HEVs are composed of two or more power sources and can be arranged in various topologies. In this thesis, a series-parallel architecture is chosen for military and garbage trucks. The studied HEVs contain a Double Planetary Geartrain as a Power Split Device (PSD), which makes the system very intricate and complex. Therefore, in this thesis, modeling of studied HEVs with a PSD is done. Later, through the assistance of Energetic Macroscopic Representation (EMR) it is graphically represented and local control structure for both vehicles are deduced.This dissertation also addresses the problem of managing energy of multiple energy sources for the studied HEVs. The Energy Management Strategy (EMS) in application to HEVs encompasses several different disciplines and challenges. Primarily, the challenges lies in managing the energy expenditure, determining the proportional power splits and establishing methods to interface between the systems so as to meet the demands of the vehicle propulsion and other load requirements. In this work, an attempt has been made to provide a new organization of EMS by decomposition in 3 explicit levels for studied vehicles i.e. military and garbage truck.
|
50 |
Monitoring procesních dat Národní vlakové linky / Monitoring of process data of National Train BusLasák, Petr January 2010 (has links)
One of the protocols used for communication between coaches inside a train is the National Train Bus (NTB). The result of this work is support for diagnostics on the NTB - mainly watching the process data-flow and monitoring of chosen variables distributed along the train, with consideration to their character and validity.
|
Page generated in 0.0484 seconds