Les travaux portent sur l’économie d’énergie dans le secteur des technologies de la communication et plus particulièrement dans les réseaux filaires. La technologie support de nos travaux est Ethernet qui historiquement utilisée dans les entreprises est actuellement déployée dans les réseaux d’accès et de coeur des opérateurs. Notre objectif est d’économiser de l’énergie par une mise en sommeil des liens Ethernet en s’appuyant sur des mécanismes standards aisément déployables. Pour ce faire nous modélisons et évaluons le mécanisme de mise en sommeil IEEE802.3az et confrontons notre modèle à l’expérimentation sur équipements. A partir du modèle de coût obtenu, nous proposons de mettre en place une ingénierie de trafic verte fonction de la charge qui dirige le trafic dans le réseau de façon à permettre aux liens de se mettre en phase de sommeil tout en préservant une qualité de service en évitant de créer des pertes de données dans le réseau par une concentration trop importante de trafic sur les liens. Nous distinguons plusieurs politiques d’ingénierie de complexité de mise en œuvre différentes, que nous évaluons dans plusieurs contextes. Les résultats obtenus permettent quasiment de doubler les gains obtenus par le standard IEEE802.3az. Nous étudions l’ingénierie dans un mode distribué à partir d’un protocole de routage, OSPF, et présentons une preuve de concept dans un mode centralisé avec une architecture SDN pour laquelle nous proposons l’utilisation du routage source par segment afin de réduire le trafic de contrôle. / This research has proposed a novel Ethernet-based global energy efficiency technology for the wired communications networks.In the development of the “green” technology, the IEEE 802.3az standard (i.e. referred to as LEGACY) was first applied to render dormant the non-utilized links to realize the local energy efficiency.To further lower the energy demand and thus achieve the global energy efficiency, this research put forward two additional algorithmic schemes(i.e. the EAGER and CARE green metrics)whereby the data are aggregated such that as many links as possible remain unutilized. The three energy-efficient metrics (LEGACY, EAGER and CARE) were individually applied to the distributed and centralized networks and subsequently evaluated.The experimental results showed that, by comparison, the CARE green metric outperforms the other two metrics (LEGACY and EAGER) with regard to the global energy saving in both the distributed and centralized wired networks.

Apresentamos um novo Protocolo de Controle de Transporte fim-a-fim, implementado somente do lado do transmissor, chamado TCP HolyWood ou, abreviadamente, TCP-HW. Em um ambiente de rede cabeada simulada, TCP HolyWood supera em vazão media três dos mais importantes protocolos TCPs já elaborados. Estamos falando de TCP Reno, TCP Westwood, e TCP Vegas; e em variação de retardo media ao TCP Reno bem como ao TCP Vegas. Alem disso, de acordo com o índice de Jain, nossa proposta e tão imparcial quanto o padrão, TCP Reno. / We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard.

Apresentamos um novo Protocolo de Controle de Transporte fim-a-fim, implementado somente do lado do transmissor, chamado TCP HolyWood ou, abreviadamente, TCP-HW. Em um ambiente de rede cabeada simulada, TCP HolyWood supera em vazão media três dos mais importantes protocolos TCPs já elaborados. Estamos falando de TCP Reno, TCP Westwood, e TCP Vegas; e em variação de retardo media ao TCP Reno bem como ao TCP Vegas. Alem disso, de acordo com o índice de Jain, nossa proposta e tão imparcial quanto o padrão, TCP Reno. / We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard.

In this paper, we introduce an effective congestion control scheme for TCP over hybrid wireless/wired networks comprising a multihop wireless IEEE 802.11 network and the wired Internet. We propose an adaptive pacing scheme at the Internet gateway for wired-to-wireless TCP flows. Furthermore, we analyze the causes for the unfairness of oncoming TCP flows and propose a scheme to throttle aggressive wired-to-wireless TCP flows at the Internet gateway to achieve nearly optimal fairness. Thus, we denote the introduced congestion control scheme TCP with Gateway Adaptive Pacing (TCP-GAP). For wireless-to-wired flows, we propose an adaptive pacing scheme at the TCP sender. In contrast to previous work, TCP-GAP does not impose any control traffic overhead for achieving fairness among active TCP flows. Moreover, TCP-GAP can be incrementally deployed because it does not require any modifications of TCP in the wired part of the network and is fully TCP-compatible. Extensive simulations using ns-2 show that TCPGAP is highly responsive to varying traffic conditions, provides nearly optimal fairness in all scenarios and achieves up to 42% more goodput than TCP NewReno.

This paper introduces an effective congestion control pacing scheme for TCP over multihop wireless networks with Internet connectivity. The pacing scheme is implemented at the wireless TCP sender as well as at the Internet gateway, and reacts according to the direction of TCP flows running across the wireless network and the Internet. Moreover, we analyze the causes for the unfairness of oncoming TCP flows and propose a scheme to throttle aggressive wired-to-wireless TCP flows at the Internet gateway to achieve nearly optimal fairness. The proposed scheme, which we denote as TCP with Gateway Adaptive Pacing (TCP-GAP), does not impose any control traffic overhead for achieving fairness among active TCP flows and can be incrementally deployed since it does not require any modifications of TCP in the wired part of the network. In an extensive set of experiments using ns-2 we show that TCP-GAP is highly responsive to varying traffic conditions, provides nearly optimal fairness in all scenarios and achieves up to 42% more goodput for FTP-like traffic as well as up to 70% more goodput for HTTP-like traffic than TCP NewReno. We also investigate the sensitivity of the considered TCP variants to different bandwidths of the wired and wireless links with respect to both aggregate goodput and fairness.

Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research. The work within this thesis is made in collaboration between the Department of Construction and Energy Engineering at Halmstad University and the Division for Electricity at Uppsala University. A 200 kW VAWT owned by the latter and situated close to Falkenberg in the southwest of Sweden has been the main subject of the research even if most learnings has been generalized to fit a typical vertical turbine. This particular turbine has a wooden tower which is semi-guy-wired, i.e. the tower is both firmly attached to the ground and supported by guy-wires. This thesis has two main topics both regarding VAWTs: eigenfrequency of the tower and the noise generated from the turbine. The eigenfrequency of a semi-guy-wired tower is studied and an analytical expression describing this is produced and verified by experiments and simulations. The eigenfrequency of the wire itself and how it is affected by wind load are also studied.  The noise characteristics of VAWTs have been investigated, both theoretically and by noise measurement campaigns. Both noise emission and frequency distribution of VAWTs has been studied. The work has resulted in analytical expressions for tower and wire eigenfrequency of a semi-guy-wired tower as well as recommendations for designing future towers for VAWTs. The noise emission of VAWTs has been studied and proven low compared to HAWTs. The noise frequency distribution of the 200 kW VAWT differs significantly from that of a similar size HAWTs with for example lower levels for frequencies below 3000 Hz.

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Access to highways from a local firehouse is a major problem for emergency services. Motorists often do not see flashing lights or hear sirens from the approaching emergency vehicles (EV) until emergency vehicles reach the highway entrance, often too late to take appropriate action. Many locations have installed special signals called emergency traffic signal systems (ETSS) or used signal preemption to notify motorists and to stop traffic to allow the emergency vehicle to enter the highway safely. This thesis will examine the effectiveness of one such installation at the intersection along U.S.1 at Beedo Street and some of the impacts it has on highway traffic. The evaluation of the said installation is carried out in terms of delay to EV; conflict potential between EV and other vehicles and response of the motorists to the ETSS. This thesis also proposes two alternative designs of ETSS to improve the existing signal system. / Master of Science

Error Resilient Coding tools are the methods to avoid or reduce the amount of corruption in video by altering the encoding algorithm. One of them is Flexible Macroblock Ordering (FMO) which provides us with ordering macroblocks of the frames flexibly. Six of them have definite ordering pattern and the last one, called explicit type, can get any order. In this thesis two explicit type algorithms, one of which is new, are explained and the performance of different FMO types in wired and wireless communication are evaluated. The first algorithm separates the important blocks into separate packets, so it equalizes the importance of packets. The proposed method allocates the important macroblocks according to a checkerboard pattern and employs unequal error protection to protect them more. The simulations are performed for wired and wireless communication and Forward Error Correction is used in the second stage of the simulations. Lastly the results of the new algorithms are compared with the performance of the other FMO types. According to the simulations the Proposed algorithm performs better than others when the error rate is very high and FEC is employed.

The aim of this diploma thesis is to design and manufacture a small modular burglar alarm control panel with an emphasis on GSM communication functions. The first part of the thesis discusses history of control panels from the first attempts to present technologies. Also a classification of wired and wireless systems is defined. The second part contains an general proposal of the GSM-enabled panel design and description of the circuit. SIM 300C module has been chosen as a GSM terminal device. The final part contains description of key parts of the firmware and a detailed manual for end users. The proposed design has been realized and succesfully tested.