The main contributions of this thesis are located in the domain of wireless sensor netorks. More in detail, we introduce energyaware algorithms and protocols in the context of the following topics: self-synchronized duty-cycling in networks with energy harvesting capabilities, distributed graph coloring and minimum energy broadcasting with realistic antennas. In the following, we review the research conducted in each case. We propose a self-synchronized duty-cycling mechanism for sensor networks. This mechanism is based on the working and resting phases of natural ant colonies, which show self-synchronized activity phases. The main goal of duty-cycling methods is to save energy by efficiently alternating between different states. In the case at hand, we considered two different states: the sleep state, where communications are not possible and energy consumption is low; and the active state, where communication result in a higher energy consumption. In order to test the model, we conducted an extensive experimentation with synchronous simulations on mobile networks and static networks, and also considering asynchronous networks. Later, we extended this work by assuming a broader point of view and including a comprehensive study of the parameters. In addition, thanks to a collaboration with the Technical University of Braunschweig, we were able to test our algorithm in the real sensor network simulator Shawn (http://shawn.sf.net). The second part of this thesis is devoted to the desynchronization of wireless sensor nodes and its application to the distributed graph coloring problem. In particular, our research is inspired by the calling behavior of Japanese tree frogs, whose males use their calls to attract females. Interestingly, as female frogs are only able to correctly localize the male frogs when their calls are not too close in time, groups of males that are located nearby each other desynchronize their calls. Based on a model of this behavior from the literature, we propose a novel algorithm with applications to the field of sensor networks. More in detail, we analyzed the ability of the algorithm to desynchronize neighboring nodes. Furthermore, we considered extensions of the original model, hereby improving its desynchronization capabilities.To illustrate the potential benefits of desynchronized networks, we then focused on distributed graph coloring. Later, we analyzed the algorithm more extensively and show its performance on a larger set of benchmark instances. The classical minimum energy broadcast (MEB) problem in wireless ad hoc networks, which is well-studied in the scientific literature, considers an antenna model that allows the adjustment of the transmission power to any desired real value from zero up to the maximum transmission power level. However, when specifically considering sensor networks, a look at the currently available hardware shows that this antenna model is not very realistic. In this work we re-formulate the MEB problem for an antenna model that is realistic for sensor networks. In this antenna model transmission power levels are chosen from a finite set of possible ones. A further contribution concerns the adaptation of an ant colony optimization algorithm --currently being the state of the art for the classical MEB problem-- to the more realistic problem version, the so-called minimum energy broadcast problem with realistic antennas (MEBRA). The obtained results show that the advantage of ant colony optimization over classical heuristics even grows when the number of possible transmission power levels decreases. Finally we build a distributed version of the algorithm, which also compares quite favorably against centralized heuristics from the literature. / Las principles contribuciones de esta tesis se encuentran en el domino de las redes de sensores inalámbricas. Más en detalle, introducimos algoritmos y protocolos que intentan minimizar el consumo energético para los siguientes problemas: gestión autosincronizada de encendido y apagado de sensores con capacidad para obtener energía del ambiente, coloreado de grafos distribuido y broadcasting de consumo mínimo en entornos con antenas reales. En primer lugar, proponemos un sistema capaz de autosincronizar los ciclos de encendido y apagado de los nodos de una red de sensores. El mecanismo está basado en las fases de trabajo y reposo de las colonias de hormigas tal y como estas pueden observarse en la naturaleza, es decir, con fases de actividad autosincronizadas. El principal objectivo de este tipo de técnicas es ahorrar energía gracias a alternar estados de forma eficiente. En este caso en concreto, consideramos dos estados diferentes: el estado dormido, en el que los nodos no pueden comunicarse y el consumo energético es bajo; y el estado activo, en el que las comunicaciones propician un consumo energético elevado. Con el objetivo de probar el modelo, se ha llevado a cabo una extensa experimentación que incluye tanto simulaciones síncronas en redes móviles y estáticas, como simulaciones en redes asíncronas. Además, este trabajo se extendió asumiendo un punto de vista más amplio e incluyendo un detallado estudio de los parámetros del algoritmo. Finalmente, gracias a la colaboración con la Technical University of Braunschweig, tuvimos la oportunidad de probar el mecanismo en el simulador realista de redes de sensores, Shawn (http://shawn.sf.net). La segunda parte de esta tesis está dedicada a la desincronización de nodos en redes de sensores y a su aplicación al problema del coloreado de grafos de forma distribuida. En particular, nuestra investigación está inspirada por el canto de las ranas de árbol japonesas, cuyos machos utilizan su canto para atraer a las hembras. Resulta interesante que debido a que las hembras solo son capaces de localizar las ranas macho cuando sus cantos no están demasiado cerca en el tiempo, los grupos de machos que se hallan en una misma región desincronizan sus cantos. Basado en un modelo de este comportamiento que se encuentra en la literatura, proponemos un nuevo algoritmo con aplicaciones al campo de las redes de sensores. Más en detalle, analizamos la habilidad del algoritmo para desincronizar nodos vecinos. Además, consideramos extensiones del modelo original, mejorando su capacidad de desincronización. Para ilustrar los potenciales beneficios de las redes desincronizadas, nos centramos en el problema del coloreado de grafos distribuido que tiene relación con diferentes tareas habituales en redes de sensores. El clásico problema del broadcasting de consumo mínimo en redes ad hoc ha sido bien estudiado en la literatura. El problema considera un modelo de antena que permite transmitir a cualquier potencia elegida (hasta un máximo establecido por el dispositivo). Sin embargo, cuando se trabaja de forma específica con redes de sensores, un vistazo al hardware actualmente disponible muestra que este modelo de antena no es demasiado realista. En este trabajo reformulamos el problema para el modelo de antena más habitual en redes de sensores. En este modelo, los niveles de potencia de transmisión se eligen de un conjunto finito de posibilidades. La siguiente contribución consiste en en la adaptación de un algoritmo de optimización por colonias de hormigas a la versión más realista del problema, también conocida como broadcasting de consumo mínimo con antenas realistas. Los resultados obtenidos muestran que la ventaja de este método sobre heurísticas clásicas incluso crece cuando el número de posibles potencias de transmisión decrece. Además, se ha presentado una versión distribuida del algoritmo, que también se compara de forma bastante favorable contra las heurísticas centralizadas conocidas.

Riksbyggen Fastighetsservice is a company whose businesses cope with building construction and related services. The local office of Riksbyggen Fastighetsservice in Gävle has been studied in this project. The local office locates in Näringen 20:4, which was constructed in 1989.   The aim of this project is to make a diagnosis of the current situation; find out the most applicable way of optimizing the operation of the facility in order to reduce the energy consumption, to study costs and possible savings and provide assistance with future energy management.      Firstly, a study of Energy Balance was conducted. The transmission losses was 57761 KWh; mechanical ventilation losses 3855 KWh; hot tap water heat losses 9579 KWh; natural transmission and infiltration 6897 KWh. On the other hand, heat gain from internal heat was 12707 KWh; solar radiation 8521 KWh; and supply heat 56806 KWh.   Secondly, the energy costs have been checked out. 29655 KWh of electricity was consumed in 2008. 5948 KWh was used by 20 fuses electricity and 23707 KWh was for 25 fuses. Lighting, electrical equipment and machine composed the electricity consumption. Lighting consumes 13278 KWh; equipment consumes 6452 KWh; and machine consumes 9925 KWh. Lighting electricity was composed by office lighting and workshop lighting with 4798 KWh and 8480 KWh respectively.   Electricity cost is very complicated and flexible in Sweden according to effect and consumption. The total cost of electricity consists of electricity commerce fee and electricity transmission net. Electricity commerce fee includes annual fixed fee, electricity fee, energy certificate and tax. Electricity transmission fee includes annual fixed transmission fee, grid fee and tax. Tax plays vital important role which results in huge total cost. The local office spent 43356 kr on electricity in 2008. 4798 kr was spent on office lighting, and 8480 kr was spent on workshop lighting.   On the other hand district heating fee is composed by annual fixed fee, effect fee, energy fee and tax. The local office spent 37142 kr on 56.806 MWh of district heating in 2008. Thus, the local office purchased 86461 KWh of energies and spent 80498 kr in total in 2008.   Thirdly, to assist its energy traces and management, three tables were designed. One table is for annual energy consumption and cost in each month with all information of sub-terms on costs. One table is for annual electricity consumption for each electrical equipment and cost in accordance. Another table is for district heating consumption and cost.    At last, energy saving possibilities was explored. One way is applying improvements or maintenance of the office construction. The result of Energy Balance shows that transmission losses were 57761 KWh which occupies 74% of the total losses, and it is the biggest bite. As the office was constructed in 1989, if improvements and maintenance can be applied to the insulation of floor, roof and walls, or change the windows, the heat losses can be reduced.   However, the other solution might be much more applicable and financial sound. Just go to Clas Ohlson to buy LED 1 W and 3 W lamps to replace the current bulbs. Spending 3009 kr to buy 51 LED incandescent bulbs of 1W effect, and 3576 kr on 24 LED fluorescent of 3W effect, will save 12057 kr every year. The lighting electricity consumption will be reduced from 13278 KWh / year to 264 KWh / year. Instead of spending 16017 kr on lighting, 98% will be reduced, and only 318 kr will be paid. Moreover, the payback is really nice, only 0.42 year. Action! The sooner the better! 20% of energy cost will be saved!

Marine shipping industry is the biggest economy of the global logistics, the cost that the vessel runs includes: personnel's salary, insurance, shipping administration expense, port charges, maintenance and fuel, etc.. Among them port charges and fuel are estimated can probably take 70% of the total operating cost, and the proportion of the fuel cost may be up to 50%. So the fuel cost is a main reason for influencing the operation performance of shipping. Because the international oil price runs high in recent years, besides designing the optimization with ship type, vessel technology and development move towards the innovative study and application of the power-saving technology, in order to reduce the operating cost. In addition, in shipping management, it is main directions to move towards maximization of ship and energy-conservation to reduce the expenditure of the cost. Until high oil price and the whole world might face economic depression unfavorable factor, the motive force of shipping is unable to store, unable to reuse, so how to popularize energy-conserving actuating device and relevant environmental protection assists the energy-saving equipment, trader to boat last economic benefits greatest and how effective management energy and last greatest benefit, study the focal point for this thesis. This thesis is in Professor Zhang Yu-Shan's guidance, starts from the operating cost of shipping, discusses shipping machines and impact on operating cost of auxiliary energy- saving equipment, investigate of the shipping business to analyze and prove it. To feedback my experiences engaged in the relevant trade of the past 20 years.

There were three big oil crises in twenty century, and all made international political shakes. The global warming triggered the climate change, the rising of sea horizon and other environmental problems. The advanced countries begin to think about decreasing the dependency of fossil fuels as economic grows. Both the Kyoto Protocol in 1997 and the United Nations Copenhagen Climate Change Conference in 2009 were the evidences that most of the countries in the world are all concerned about climate change and economical environments. Furthermore, the Kyoto Protocol and the United Nations Climate Change Conferences affected the global economic policies, and also generated new ideas of green economy. Because of the impacts from the environmental and economic view, many countries made new green energy policies to develop renewable energy, promote green industry, wake up environment protection ideas, and broadcast the education of save energy saving and carbon reduction. This thesis uses the historical method, content analysis method and comparative method and the public policy theory as the theory basement. Then the thesis introduces the summary of global green energy industry. Taiwan and Singapore are called as Four Asian Little Dragons, but both lack of nature resources and depend on energy importation. The thesis discusses the policies on green industry of the Taiwan and Singapore, and also discusses the outputs of the policies. The final part is the policy comparisons between the two governments.

In this dissertation, we studied methods for improving efficiency and effectiveness of multipath routing in computer networks. We showed that multipath routing can improve network performance for failure recovery, load balancing, Quality of Service (QoS), and energy consumption. We presented a method for reducing the overhead of computing dynamic path metrics, one of the obstacles for implementing dynamic multipath routing in real world networks. In the first part, we proposed a method for building disjoint multipaths that could be used for local failure recovery as well as for multipath routing. Proactive failure recovery schemes have been recently proposed for continuous service of delay-sensitive applications during failure transients at the cost of extra infrastructural support in the form of routing table entries, extra addresses, etc. These extra infrastructure supports could be exploited to build alternative disjoint paths in those frameworks, while keeping the lengths of the alternative paths close to those of the primary paths. The evaluations showed that it was possible to extend the proactive failure recovery schemes to provide support for nearly-disjoint paths which could be employed in multipath routing for load balancing and QoS. In the second part, we proposed a method for reducing overhead of measuring dynamic link state information for multipath routing, specifically path delays used in Wardrop routing. Even when dynamic routing could be shown to offer convergence properties without oscillations, it has not been widely adopted. One of reasons was that the expected cost of keeping the link metrics updated at various nodes in the network. We proposed threshold-based updates to propagate the link state only when the currently measured link state differs from the last updated state consider- ably. Threshold-based updates were shown through analysis and simulations to offer bounded guarantees on path quality while significantly reducing the cost of propagating the dynamic link metric information. The simulation studies indicated that threshold based updates can reduce the number of link updates by up to 90-95% in some cases. In the third part, we proposed methods of using multipath routing for reducing energy consumption in computer networks. Two different approaches have been advocated earlier, from traffic engineering and topology control to hardware-based approaches. We proposed solutions at two different time scales. On a finer time granularity, we employed a method of forwarding through alternate paths to enable longer sleep schedules of links. The proposed schemes achieved more energy saving by increasing the usage of active links and the down time of sleeping links as well as avoiding too frequent link state changes. To the best of our knowledge, this was the first technique combining a routing scheme with hardware scheme to save energy consumption in networks. In our evaluation, alternative forwarding reduced energy consumption by 10% on top of a hardware-based sleeping scheme. On a longer time granularity, we proposed a technique that combined multipath routing with topology control. The proposed scheme achieved increased energy savings by maximizing the link utilization on a reduced topology where the number of active nodes and links are minimized. The proposed technique reduced energy consumption by an additional 17% over previous schemes with single/shortest path routing.

Fluidized bed combustion (FBC) ashes containing significant amount of free CaO and CaSO4 in addition to valuable inorganic acidic oxide ingredients such as SiO2, Fe2O3 and Al2O3 can be utilized as potential raw materials in the production of nonexpansive belite-rich calcium sulfoaluminate cement which is one of the special cement type of sulfoaluminate-belite cements having performance characteristics similar to those of ordinary portland cement besides lower energy requirements and CO2 emissions during manufacturing. Therefore, in this thesis study, possibility of producing non-expansive belite-rich calcium sulfoaluminate cement by adding FBC ashes in various proportions to the raw meal was investigated. For this purpose, a raw meal composed a mixture of limestone, bauxite, gypsum together with 10 wt % bottom ash and 15 wt % baghouse filter ash was prepared. It was sintered in a laboratory scale muffle furnace at temperatures of 1200, 1250 and 1300 &deg / C for various holding times. The results of chemical and mineralogical analysis as well as microscopic examination reveal that FBC ashes have the potential to be used in the raw meal due to the presence of characteristic mineral phases of this type of cements, i.e. yeelimite, larnite, ferrite and anhydrite, in the sample obtained at optimum sintering temperature of 1250 &deg / C for 60 min.

The energy service industry is a newly emerging industry in Taiwan, where related regulations and measures are still at an immature stage. The business operation models include being a motivator in regard to energy conservation, becoming an ESCO, or developing strategies covering both areas. The implementation will help present energy users to break through existing bottlenecks involving: funds, manpower, technology, and recycling term; change the environment where the Government is currently the main motivator; and attract private companies to participate in energy saving and carbon reduction. First, topics for in-depth interviews were established in order to obtain a better understanding of the operational environment of ESCOs in Taiwan, including any obstructions encountered during the development of the ESCO industry. Second, in-depth interviews were carried out with selected ESCOs via explorative research and quantitative methods. The interview data were analyzed and discussed. The following results were obtained regarding the domestic ESCO industry: 1. The status of current development and business opportunities is promising. 2. Factors affecting current development include the lack of regulations, subsidizing plans, third party authentication, energy-saving technologies, and financing solutions. 3. The financing difficulties include: insufficient collateral, sound financial reports, or banks¡¦ understanding of the ESCO industry. 4. The key success factors for the domestic ESCOs to enter the global ESCO market include: the accuracy of the energy-saving reports and income estimates, provision of integrated energy-saving technologies, and utilization of the small and medium business credit guarantee funds and loans. 5. Business models that best suit the development of domestic ESCOs include: sharing energy, performance guarantees, and equipment lease.

Energy saving, in battery operated wireless sensor networks, for the purpose of increasing the node and network lifetime, has gained substantial importance. This research was conducted with the objective of reducing the power consumption of the MICA2 sensors. The objective was pursued by manipulating the MAC layer, and by introducing a dynamic transmission power control algorithm. A new simulation tool was developed in order to reduce the complexity related to the design and testing of the transmission power control algorithm. The power control algorithm was also developed in the NesC language for the MICA2 sensors. In addition,several modifications were introduced to the original MAC protocol. Data, derived from both simulations and experiments, demonstrated that a significant reduction in energy expenditure was achieved, for the MICA2 sensors. In addition,the data revealed that the network lifetime was extended. This research dramatically illustrated the energy saving potential of the application of transmission power control procedures in wireless sensor networks.

Koldioxidnivåerna ökar i takt med en allt högre världslig energianvändning. Detta har lett till reglering och bestämmelser av utsläppsrätter samt energianvändning. För att stoppa den globala uppvärmningen och minska energianvändningen har EU enats om fyra gemensamma mål att uppnå till år 2020, även benämnda 20-20-20 målen. Lika så har Sverige satt upp egna miljömål att sträva efter till år 2020. De omfattar en ökning av andel förnyelsebar energi med minst 50 procent, effektivisera energianvändningen med minst 20 procent samt öka andelen förnyelsebar energi i transportsektorn med minst 10 procent.  Tack vare lagar gällande krav på skärpt energianvändning och utsläpp strävar företag mot användandet av energieffektivare teknik och ett mer energimedvetet beteende. Energikartläggning är ett viktigt samt effektivt verktyg vid kartläggning och illustrering av ett företags energianvändning för underlättande och tydliggörande av framtida åtgärd samt förbättring.  Examensarbetet syftar till att åskådliggöra Kv. Fredens energianvändning samt ta fram ekonomiskt genomförbara energibesparande åtgärder för att sänka energianvändningen både för denna och liknande byggnader. Till hjälp för utförande har sex frågeställningar använts vilka berör och syftar till att ta reda på energifördelningen i byggnaden, brister i drift och uppehållande av inomhusklimat samt ta fram kostnadseffektiva lösningar för val av åtgärd.För tillvägagång av arbetet har fem metoder valts för besvarande av frågeställningar. En litteraturstudie utfördes med hjälp av nyckelord som ”Energy saving”, ”Energy audit” samt ”Behaviour” i online-databaser för vetenskapliga artiklar. Därefter utfördes en empirisk analys av tillhandahållen data för byggnaden, vilket möjliggjorde modellering och simulering av byggnaden i programmet IDA ICE 4.6.1. För styrkande av antaganden samt undersökning av energimedvetet beteende utfördes termografering och en kvalitativ enkätundersökning.  Efter utförande av arbetet med hjälp av nämnda metoder, konstateras bristfällig ventilation. Vid simulerad installation av FTX i byggnaden uppnås en maximal energibesparing på dryga 17 procent, vilket motsvarar en slutlig energianvändning på 97 kWh/m2. Simulerade åtgärder, exklusive FTX, vilka visar sig vara mest lönsamma för byggnaden är tätning av dörrar och fönster för minskad infiltration. Dessa två simulerade åtgärder är de mest kostnadseffektiva simulerade lösningarna för Kv. Freden samt liknande byggnader.   Den simulerade energianvändningen för byggnaden representeras av 29 procent elanvändning samt 71 procent fjärrvärmeanvändning, vilka förhåller sig till en tillförlitlighet motsvarande 97,5 procent respektive 96 procent jämfört med energidata tillhandahållen av Gävle Energi. Simuleringsprogrammet IDA ICE visade sig vara ett effektivt hjälpmedel vid simulering av en byggnads energianvändning samt applicering av möjliga åtgärder. / Carbon dioxide levels are increasing as a consequence of larger energy use worldwide. This has led to regulations and rules of emission and energy consumption. In order to stop global warming and reduce energy consumption, EU has agreed on four common goals to achieve by the year 2020, also known as the 20-20-20 goals. Sweden has also come up with its own environmental goals to achieve by the year 2020. They include increasing the share of renewable energy by at least 50 percent, improve the use of energy by at least 20 percent and increase the share of renewable energy in the transportation sector by at least 10 percent.   Due to the laws and requirements related to stricter energy consumption and carbon emissions companies strive to use more energy efficient technology and more energyconscious behavior. Energy audit is an effective and an important tool in identifying and illustrating a company's energy usage for the clarification of future measures and improvement.  The thesis aims to illustrate Kv. Freden's use of energy and come up with both economically and energy saving measures to reduce its and other similar building's energy consumption. Six questions have been used to determine the energy distribution in the building and find defects in the management and maintenance of the indoor climate and develop cost-effective solutions for the choice of measures.   Five methods were chosen for approaching and answering the questions. A literature review was performed using keywords such as "Energy Saving", "Energy Audit" and "Behaviour" in online databases containing scientific articles. Thereafter an empirical analysis of the data supplied for the building was performed, which enabled modeling and simulation of the building in the program IDA ICE 4.6.1. A thermography and a qualitative survey regarding energy conscious behavior were performed as proof of assumptions.  The ventilation in this thesis is found inadequate after applied methods.  With simulated FTX-systems installed in the building, a maximum energy saving potential about 17 percent is achieved, which corresponds to a energy use of 97 kWh/m2. Excluding FTX, the simulated measures which prove to be the most profitable for the building is the sealing of doors and windows in order to reduce infiltration. These two measures are the most cost effective energy saving solutions regarding Kv. Freden and similar buildings.  The building's simulated energy use is represented by 29 percent electricity and 71 percent of district heating usage, which compared with the energy data provided by Gävle Energi relates to a reliability equivalent to 97.5 percent and 96 percent. The simulation program IDA ICE proved to be an efficient tool for the simulation of a building's energy use and application of possible measures.

Device-to-device communication has been suggested as a complement to traditional cellular networks as a means of offloading cellular traffic. In this thesis we explore a solution for device-to-device communication based on opportunistic content distribution in a content-centric network. Communication opportunities arise as mobile nodes roam around in an area and occasionally enter in direct communication range with one another. We consider a node to be a pedestrian equipped with a mobile device and explore the properties of opportunistic communication in the context of content dissemination in urban areas. The contributions of this thesis lie in three areas. We first study human mobility as one of the main enablers of opportunistic communication. We introduce traces collected from a realistic pedestrian mobility simulator and demonstrate that the performance of opportunistic networks is not very sensitive to the accurate estimation of the probability distributions of mobility parameters. However, capturing the space in which mobility occurs may be of high importance. Secondly, we design and implement a middleware for opportunistic content-centric networking, and we evaluate it via a small-scale testbed, as well as through extensive simulations. We conclude that energy-saving mechanisms should be part of the middleware design, while caching should be considered only as an add-on feature. Thirdly, we present and evaluate three different energy-saving mechanisms in the context of opportunistic networking: a dual-radio architecture, an asynchronous duty-cycling scheme, and an energy-aware algorithm which takes into account node selfishness. We evaluate our proposals analytically and via simulations. We demonstrate that when a critical mass of participants is available, the performance of the opportunistic network is comparable to downloading contents directly via the cellular network in terms of energy consumption while offloading large traffic volumes from the operator. / <p>QC 20151120</p>