Abstract

This thesis aims to improve a satellite communication network which carries both data streams and Voice over IP (VoIP) communication sessions with resource reservation. The resource reservations are made using the standard protocols for Traffic Engineering: MPLS-TE and RSVP-TE. The goal of this thesis project is to optimize the number of concurrent VoIP calls that can be made, in order to use the available bandwidth while maintaining a guaranteed Quality of Service (QoS) level, which is not possible in the existing system. This thesis proposes and evaluates a solution to this optimization problem in the specific context of a satellite modem system that was developed by Thales Communications. This optimization improves the system's ability to carry VoIP communications through better use of the available transmission resources. A solution to this problem would also increase the  exibility in bandwidth allocation within the modem system, and could provide a framework for future development. The proposed solution allows all of the reservable bandwidth to be used.  The amount of reservable bandwidth must be at least a little lower than the channel's available bandwidth in order to avoid congestion. Some areas of future work are proposed. Detta projekt har försökt förbättra ett datornätverk bestående av satelliter som används till både data och Voice over IP (VoIP) kommunikation. VoIP använder sig av resursreservation som bestäms av standardprotokollen för Traffic Engineering, MPLS-TE och RSVP-TE.  Målet är att optimera antalet samtidiga VoIP samtal så att det mesta av den befintliga bandbredden kan utnyttjas samtidigt som Quality of Service (QoS) kan garanteras. Detta är omöjligt i det befintliga systemet. Projektet föreslår en lösning för problemet med modemet som utvecklas av Thales Communications och utvärderar därefter lösningen. Dessa optimeringar förbättrar systemets förmåga att driva VoIP kommunikationer genom att bättre använda de befintliga resurserna. En lösning för det här problemet skulle höja systemets flexibilitet och kunna användas som underlag för kommande utvecklingar. Tack vare lösningen kan hela utsedda bandbredden reserveras. Antalet bandbredd som kan reserveras måsta vara minst lite lågre än total befintling bandbredd för att undvika överbelastning. även några möjliga ideer för vidare undersökning föreslås. Ce projet a pour but d'améliorer un réseau de communication par satellite utilisé pour transporter des flux de données ainsi que des sessions de communication Voix sur IP (VoIP) avec réservation de ressources. Les réservations sont prises en charge par les protocoles standard de Traffic Engineering que sont MPLS-TE et RSVP-TE. L'objectif de ce projet est d'optimiser le nombre d'appels VoIP pouvant être passés en parallèle afin d'utiliser autant de bande passante que possible tout en offrant un niveau de Qualité de Service (QoS) garanti, chose impossible dans le système actuel. Ce rapport propose et évalue une solution à ce problème d'optimisation dans le contexte spécifique du modem satellite développé par Thales Communications. Ces optimisations amélioreraient la capacité du système à transporter des communications VoIP grâce à une meilleure utilisation des ressources disponibles pour la transmission. Une solution à ce problème rendrait aussi l'allocation de ressources plus flexible au sein du système, et pourrait fournir une base à de futurs développements. La solution proposée permet l'utilisation de toute la bande passante réservable. La quantité réservable doit être un peu inférieure à la bande passante totale disponible afin d'éviter la congestion. Les résultats de ces évaluations sont exposés. Enfin, ce rapport propose de futurs développements possibles.

Abstract

The Nordic power system is facing the challenge of the ongoing decrease of synchronous generation along with increased penetration of inverter based renewable generation leading to reduced system inertia. Meanwhile, the electrification of the transport sector will result in a significant amount of additional electrical loads. However, the electrification of private transport is a technology of growing interest that can provide flexibility to the power system if adequately utilized. Electric vehicles (EV) can be considered as temporary energy storage with availability, energy and capacity constraints. In this paper, we use first hand data of a real EV fleet of Tesla vehicles and their historical driving patterns to develop a two-stage stochastic optimization problem. This model maximizes the profit of a risk-averse EV aggregator that aims to place optimal bids on the day ahead in both energy and Frequency Containment Reserve (FCR) markets. Only uni-directional charging is examined, while we take into account uncertainty from prices and vehicle utilization. Case studies are carried out modelling individual vehicle driving behavior in different Nordic price areas in both winter and summer. We identify a strong alignment of EV availability and periods of high FCR prices. Results show that consumption is shifted largely towards early hours of the morning. When compared to a  reference ”cost of charging case”, up to 50% of the cost of charging can be covered in Norway, while the entire cost is met in Sweden. "p"QC 20181017

Abstract

Self-organization in active materials, inspired by biological systems, shows many features, not found in passive materials. In order to explore the influence of shape asymmetry, a new 2D shape, named a circulangle, is introduced. Kinetic Monte Carlo simulations of two-dimensional hard Brownian circulangles are presented. Self-propulsion is introduced by additional MC moves along particles' axes. The system undergoes transition from homogeneously distributed particles to micellar structures arranged in clusters/networks. Circulangles appear to be the first known self-propelled particles, which form micelles without attractive forces. The newly discovered phenomenon may have wide implications in design of (meta)materials for energy conversion and storage, sensorics, micromechanics, targeted drug delivery, swarm intelligence, etc.

Abstract

Decarbonization is one of the biggest challenges of our time. The European Union, as other organizations have already designed the strategies to achieve a more sustainable future. The integration of renewable energy sources is not a technical challenge anymore. However, due to the variability of these type of technologies some actions should be implemented so the conventional ones are not needed any more. One crucial solution is the implementation of demand side management actions which focus on controlling the demand rather than the generation. This thesis identifes the diferent actions on diferent demand side management actions and their performance in Spain. Also, an analysis regarding implemented policies in other European countries is performed to identify successful actions that could be later implemented in Spain. Ingeniería de la Energí

Abstract

The scope of this paper is to derive a set of simple formulas providing a traffic aggregation in important points of an Internet access networks. The paper shows that the resources associated to the access network depend on user type-, technology and service parameter. Existing calculation methodologies applies on individual approximations whereas this proposal exposes the combined application of these individual and wellknown approximations providing a scheme of generic dimensioning formulas. The dimensioning formulas for a generic applications are derived for the three main levels: connection, session and burst level, and the traffic aggregation is considered through three different and combined variables describing users, accesses and services forming a cube with three axes. The adaptation of corresponding parameters following the different axes allows the calculation of complete access network traffic scenarios, grouped by the so called CASUAL concept: Cube of Accesses / Services / Users. A set of CASUAL based tools allows an estimation of the aggregated traffic in different access points as multiplexers, IP point of presence or edge routers.

Abstract

Flexibility of small loads, in particular from Electric Vehicles (EVs), has recently attracted a lot of interest due to their possibility of participating in the energy market and the new commercial potentials. Different from existing work, the aggregation technique proposed in this paper produces flexible aggregated loads from EVs taking into account technical market requirements. The flexible aggregated loads can be further traded in the day-ahead market by a Balance Responsible Party (BRP) via the so-called flexible orders. As a result, the BRP can achieve more than 19% cost reduction in energy purchase based on the 2017 real electricity prices from Danish electricity market. Peer Reviewed