The IEEE 802.11 standard has been widely adopted as a Wireless LAN (WLAN) technology. This widespread proliferation of the technology has lead to an increase in the number of users taking advantage of so-called "hot-spots" which leads to an increased demand on bandwidth provided by Access Points (APs) in the hot-spot. The logical solution is to deploy more overlapping access points in the same coverage area, thus increasing the capacity of the system by providing load balancing services. However, when a hot-spot is located in an outdoor environment, it becomes difficult to provide the AP with power which is traditionally carried over wired links thus causing the service provider to incur additional costs, not to mention the impossibility in some cases of delivering power to the AP. This problem can be overcome by using solar-panel powered APs which we will refer to as solar nodes (SNs). In this thesis we examine the load-balancing problem that arises when two or more SNs are co-located in the same coverage area. We propose and evaluate two algorithms for efficiently distributing the load among them (transferring stations (STAs) from SN to neighboring SNs) and increasing their lifetime by using power saving schemes that co-ordinate the wake/sleep patterns of the SNs based on traffic load. Finally, a Connection Admission Control (CAC) function is proposed that the SN should use in order to provide controlled access to services. We demonstrate through simulations that our proposals can significantly reduce the hardware requirements and cost of SNs and improve the service perceived by STAs in terms of transmission delay. / Thesis / Master of Applied Science (MASc)

In this research paper, review of world geothermal energy production and their capacity is shown. Here, a research is conducted to know the potential and possibility of geothermal energy in India. All the geothermal province with their geographical locations are shown and a brief calculation is conducted in order to show the potential of the particular province. As India is having the low temperature geothermal fields, binary geothermal plants are used for this analysis and results are calculated by using R134a as a working fluid at different temperatures. The results are sufficient to prove the potential of geothermal energy in India.  Importance of Ground Source Heat Pump (GSHP) and power savings by its contribution over traditional heating and cooling methods is shown statistically. 9 different states of India are divided by their climatic condition, severe winter and moderate winter to calculate the heat demand in those states. Also, for the cold demands these states are considered to be same as per the climatic situation in summer. Then, comparison is done between GSHP and the traditional heating and cooling systems. The result shows the drastic power saving by using GSHP for space heating as well as cooling, over electric heater and air conditioner respectively.

In this thesis, We propose two power saving strategy in wireless sensor networks with multi-packet reception and slotted ALOHA is as a systematic model. We concentrate on the case in which the packet arrival process is Bernoulli and the maximum queue is 1.This thesis first simulate results and to compare with the analytical results of pervious thesis. Traditional slotted ALOHA only have transmit and idle state. In this thesis, add a sleep state to decrease the energy consumption, and according to different strategy propose two different methods. This two methods decide to the sleep time and the retransmission probability to achieve the energy-efficient. At last we will use the simulation result to show the performance of our power saving strategy.

This thesis deals with determine location using very low power consumption device. The main target was to design and construct device using right platform and sensors for localization, sending data using IoT LoRa network and than processing data on server's side. To solve the problem, it was used community network TheThingsNetwork. In thesis I created power efficient device, which can find current location using GPS system and deliver it to user using LoRaWAN network.

Tesis por compendio / Nowadays, thanks to the continuous improvements in the integration scale, more and more cores are added on the same chip, leading to higher system performance. In order to interconnect all nodes, a network-on-chip (NoC) is used, which is in charge of delivering data between cores. However, increasing the number of cores leads to a significant power consumption increase, leading the NoC to be one of the most expensive components in terms of power. Because of this, during the last years, several mechanisms have been proposed to address the NoC power consumption by means of DVFS (Dynamic Voltage and Frequency Scaling) and power-gating strategies. Nevertheless, improvements achieved by these mechanisms are achieved, to a greater or lesser extent, at the cost of system performance, potentially increasing the risk of saturating the network by forming congested points which, in turn, compromise the rest of the system functionality. One side effect is the creation of the "Head-of-Line blocking" effect where congested packets at the head of queues prevent other non-blocked packets from advancing. To address this issue, in this thesis, on one hand, we propose novel congestion control techniques in order to improve system performance by removing the "Head-of-Line" blocking effect. On the other hand, we propose combined solutions adapted to DVFS in order to achieve improvements in terms of performance and power. In addition to this, we propose a path-aware power-gating-based mechanism, which is capable of detecting the flows sharing buffer resources along data paths and perform to switch them off when not needed. With all these combined solutions we can significantly reduce the power consumption of the NoC when compared with state-of-the-art proposals. / Hoy en día, gracias a las mejoras en la escala de integración cada vez se integran más y más núcleos en un mismo chip, mejorando así sus prestaciones. Para interconectar todos los nodos dentro del chip se emplea una red en chip (NoC, Network-on-Chip), la cual es la encargada de intercambiar información entre núcleos. No obstante, aumentar el número de núcleos en el chip también conlleva a su vez un importante incremento en el consumo de la NoC, haciendo que ésta se convierta en una de las partes más caras del chip en términos de consumo. Por ello, en los últimos años se han propuesto diversas técnicas de ahorro de energía orientadas a reducir el consumo de la NoC mediante el uso de DVFS (Dynamic Voltage and Frequency Scaling) o estrategias basadas en "power-gating". Sin embargo, éstas mejoras de consumo normalmente se obtienen a costa de sacrificar, en mayor o menor medida, las prestaciones del sistema, aumentado potencialmente así el riesgo de saturar la red, generando puntos de congestión que, a su vez, comprometen el rendimiento del resto del sistema. Un efecto colateral es el "Head-of-Line blocking", mediante el que paquetes congestionados en la cabeza de la cola impiden que otros paquetes no congestionados avancen. Con el fin de solucionar este problema, en ésta tesis, en primer lugar, proponemos técnicas novedosas de control de congestión para incrementar el rendimiento del sistema mediante la eliminación del "Head-of-Line blocking", mientras que, por otra parte, proponemos soluciones combinadas adaptadas a DVFS con el fin de conseguir mejoras en términos de rendimiento y energía. Además, proponemos una técnica de "power-gating" orientada a rutas de datos, la cual es capaz de detectar flujos de datos compartiendo recursos a lo largo de rutas y apagar dichos recursos de forma dinámica cuando no son necesarios. Con todas éstas soluciones combinadas podemos reducir el consumo de energía de la NoC en comparación con otras técnicas presentes en el estado del arte. / Hui en dia, gr\`acies a les millores en l'escala d'integraci\'o, cada vegada s'integren m\'es i m\'es nuclis en un mateix xip, la qual cosa millora les seues prestacions. Per tal d'interconectar tots els nodes dins el xip es fa \'us d'una Xarxa en Xip (NoC; Network-on-Chip), la qual \'es l'encarregada d'intercanviar informaci\'o entre els nuclis. No obstant aix\`o, incrementar el nombre de nuclis en el xip tamb\'e comporta un important augment en el consum de la NoC, la qual cosa fa que aquesta es convertisca en una de les parts m\'es costoses del xip en termes de consum. Per aix\`o, en els \'ultims anys s'han proposat diverses t\`ecniques d'estalvi d'energia orientades a reduir el consum de la NoC mitjançant l'\'us de DVFS (Dynamic Voltage and Frequency Scaling) o estrat\`egies basades en ``power-gating''. Malgrat aix\`o, aquestes millores en les prestacions normalment s'obtenen a costa de sacrificar, en major o menor mesura, les prestacions del sistema i augmenta aix\'i el risc de saturar la xarxa al generar-se punts de congesti\'o, que al mateix temps, comprometen el rendiment de la resta del sistema. Un efecte col-lateral \'es el ``Head-of- Line blocking'', mitjançant el qual, els paquets congestionats al cap de la cua, impedixen que altres paquets no congestionats avancen. A fi de solucionar eixe problema, en aquesta tesi, en primer lloc, proposem noves t\`ecniques de control de congesti\'o amb l'objectiu d'incrementar el rendiment del sistema per mitj\`a de l'eliminaci\'o del ``Head-of- Line blocking'', i d'altra banda, proposem solucions combinades adaptades a DVFS amb la finalitat d'aconseguir millores en termes de rendiment i energia. A m\'es, proposem una t\`ecnica de ``power-gating'' orientada a rutes de dades, la qual \'es capa\c c de detectar fluxos de dades al compartir recursos al llarg de les rutes i apagar eixos recursos de forma din\`amica quan no s\'on necessaris. Amb totes aquestes solucions combinades podem reduir el consum d'energia de la NoC en comparaci\'o amb altres t\`ecniques presents en l'estat de l'art. / Escamilla López, JV. (2017). Head-of-Line Blocking Reduction in Power-Efficient Networks-on-Chip [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90419 / Compendio

Dans le cadre des réseaux ad hoc à grande envergure, le concept de clusterisation peut être mis à profit afin de faire face aux problèmes de passage à l'échelle et d'accroître les performances du système. Tout d’abord, cette thèse présente notre algorithme de clusterisation TBCA ‘Tiered based Clustering algorithm’, ayant pour objectif d’organiser le processus de clusterisation en couches et de réduire au maximum le trafic de contrôle associé à la phase d’établissement et de maintenance de l’infrastructure virtuelle générée. La formation et la maintenance d’une infrastructure virtuelle ne sont pas une fin en soi. Dans cet axe, on a exploité les apports de notre mécanisme de clusterisation conjointement avec le mode veille, à travers la proposition de l’approche de conservation d’énergie baptisée CPPCM ‘Cluster based Prioritized Power Conservation Mechanism’ avec deux variantes. Notre objectif principal est de réduire la consommation d’énergie tout en assurant l’acheminement des paquets de données sans endurer des temps d’attente importants aux niveaux des files d’attente des nœuds impliqués dans le transfert. Nous avons proposé aussi un algorithme de routage LCR ‘Layered Cluster based Routing’ se basant sur l’existence d’une infrastructure virtuelle. L’exploitation des apports de notre mécanisme TBCA et la limitation des tâches de routage additionnelles à un sous ensemble de nœuds sont des atouts pour assurer le passage à l’échelle de notre algorithme. / Relying on a virtual infrastructure seems a promising approach to overcome the scalability problem in large scale ad hoc networks. First, we propose a clustering mechanism, TBCA ‘Tiered based Clustering algorithm’, operating in a layered manner and exploiting the eventual collision to accelerate the clustering process. Our mechanism does not necessitate any type of neighbourhood knowledge, trying to alleviate the network from some control messages exchanged during the clustering and maintenance process. Since the energy consumption is still a critical issue, we combining a clustering technique and the power saving mode in order to conserve energy without affecting network performance. The main contribution of our power saving approach lies on the differentiation among packets based on the amount of network resources they have been so far consumed. Besides, the proposed structure of the beacon interval can be adjusted dynamically and locally by each node according to its own specific requirements. We propose also a routing algorithm, LCR ‘Layered Cluster based Routing’. The basic idea consists on assigning additional tasks to a limited set of dominating nodes, satisfying specific requirements while exploiting the benefits of our clustering algorithm TBCA.

In this thesis, we propose a power saving strategy based on tree splitting algorithm in wireless sensor network with multiple packet reception. We concentrate on the case that maximum queue size is 1. We derive both analytical results and simulation results. We use theory of Markov chain to analyze the evolution of the system state. In addition, we propose to use Renewal theory to calculate the throughput. Furthermore, we obtain the average system size, the packet blocking probability, and the average packet delay. Because the network model is distributed, we can¡¦t understand the state of network all the time. So we use the length of last collision resolution cycle to predict the length of next cycle, and determine the sleeping time by the predicted length of next cycle to implement power saving. At last we will use the simulation result to show the performance of our power saving strategy.

High Performance Computing (HPC) has become an indispensable tool for the scientific community to perform simulations on models whose complexity would exceed the limits of a standard computer. An unfortunate trend concerning HPC systems is that their power consumption under high-demanding workloads increases. To counter this trend, hardware vendors have implemented power saving mechanisms in recent years, which has increased the variability in power demands of single nodes. These capabilities provide an opportunity to increase the energy efficiency of HPC applications. To utilize these hardware power saving mechanisms efficiently, their overhead must be analyzed. Furthermore, applications have to be examined for performance and energy efficiency issues, which can give hints for optimizations. This requires an infrastructure that is able to capture both, performance and power consumption information concurrently. The mechanisms that such an infrastructure would inherently support could further be used to implement a tool that is able to do both, measuring and tuning of energy efficiency. This thesis targets all steps in this process by making the following contributions: First, I provide a broad overview on different related fields. I list common performance measurement tools, power measurement infrastructures, hardware power saving capabilities, and tuning tools. Second, I lay out a model that can be used to define and describe energy efficiency tuning on program region scale. This model includes hardware and software dependent parameters. Hardware parameters include the runtime overhead and delay for switching power saving mechanisms as well as a contemplation of their scopes and the possible influence on application performance. Thus, in a third step, I present methods to evaluate common power saving mechanisms and list findings for different x86 processors. Software parameters include their performance and power consumption characteristics as well as the influence of power-saving mechanisms on these. To capture software parameters, an infrastructure for measuring performance and power consumption is necessary. With minor additions, the same infrastructure can later be used to tune software and hardware parameters. Thus, I lay out the structure for such an infrastructure and describe common components that are required for measuring and tuning. Based on that, I implement adequate interfaces that extend the functionality of contemporary performance measurement tools. Furthermore, I use these interfaces to conflate performance and power measurements and further process the gathered information for tuning. I conclude this work by demonstrating that the infrastructure can be used to manipulate power-saving mechanisms of contemporary x86 processors and increase the energy efficiency of HPC applications.

近年來隨著智慧型手機的興起，人們開始利用智慧型手機處理日常生活事務及社群娛樂。無形中，已逐漸的改變日常行為模式。因此，許多學者也開始進行人們使用智慧型手機狀況的研究。 若透過傳統問卷等方式蒐集分析使用記錄，受訪者可能因訪問員的外在因素而影響問卷有效性。為解決此問題，很多研究開始在智慧型手機中安裝應用程式，蒐集使用記錄，藉以分析使用行為。然現今此類應用程式，都是為特定的研究進行開發，缺乏了彈性的考量。因此，本論文設計一個是用於安卓智慧型手機的可客製化行為感測記錄器，提供研究學者依各自需需求產生實驗項目規格檔，由受測者下載至手機，透過我們的行為感測記錄器，記錄平時手機操作行為之相關記錄，並於指定之時機下將記錄上傳供研究學者統計分析，以符合個別實驗之要求。 本研究重點在於如何定義彈性且多樣化的實驗設定檔，並考量載記錄感測過程中，電力大量消耗和受測者隱私資保護的議題，提出因應的解決方法。我們設計與執行幾個實驗來驗證此行為感測記錄器，初步看來，此記錄器可以滿足我們的主要需求，但結果也導引出一些需改進的設計議題。 / In recent years, with the rise of smart phones, the public began to take advantage of smart phones in daily life and social engagements. Virtually, smart phones have gradually changed people's behavior patterns so that researchers are eager to understand the how people use smartphones in their daily life. In this thesis, we present a configurable activity logger for Android smartphones for recording a smartphone’s sensor data and the user’s operations. Instead of one Android App for each researcher’s experiment, our approach is to devise a general logger App that can be customized to collect different data items according to the needs of various researchers. Specifically, our logger App accepts experiment configuration files in which researchers specify what data items to collect and at what frequency, and then conduct the logging task accordingly for each experiment. In other words, our logger works like an interpreter on such experiment configure files. Besides customizability of logging items, our logger concerns the saving of electricity and the preservation of user privacy. Firstly, we have applied various power saving tips published in the literature to the design of our logger. Secondly, we have refrained from collecting any contents that may reveal the user’s identify or that may invade user’s privacy. To evaluate our logger, we have designed and implemented a few data collection experiments. The preliminary results show that our logger can fulfill most of the requirements we set up, though thy also reveal some improvements we need to work on in the future.

The present work was developed in the experimental area of the project "Pequeno Produtor, Grande Empreendedor that it is an area of vegetables production. It is located in the municipal district of Itabaiana in the state of Sergipe. The objective was to project and to create an automatized control of an irrigation system by leak, verifying the productive aspects related to the sustainability indicators. The calculation for water replacement in the soil was based on the estimate of the evapotranspiration starting from the reading of the climatological greatness accomplished by the agriculture-meteorological station installed at the experiment place. The equation of Penman-Montheith was used, recommended by the Food and Agricultural Organization of the United Nations (FAO). Once the estimated evapotranspiration was known, the control system did the other calculations to establish the time for the replacement of the necessary water sheet. The final comparison between the experiment and the normal production used by the producer points to a significant profit in the consumption of water and electric power. The microcontrolled control besides contributing for the decrease of the consumption of water supplies and electric power also provided an economy in the maintenance of the installed equipments. Doing so, a possibility of a higher economical profit is presented, contributing for life improvement of the small family producers, making their social and economic indicators better. / O presente trabalho foi desenvolvido na área experimental do projeto Pequeno Produtor Grande Empreendedor que é uma área de produção de hortaliças. Fica localizada no município de Itabaiana no estado de Sergipe. O objetivo foi projetar e criar um controle automatizado de um sistema de irrigação por gotejamento, verificando os aspectos produtivos relacionados com os indicadores de sustentabilidade. O cálculo para a reposição de água no solo foi baseado na estimativa da evapotranspiração a partir da leitura das grandezas climatológicas realizadas pela estação agro-meteorológica instalada no local do experimento. Utilizou-se a equação de Penman-Montheith, considerada padrão desde 1998 e recomendada pela Food and Agricultural Organization of the United Nations (FAO). Conhecida a evapotranspiração estimada, o sistema de controle realizou os demais cálculos para estabelecer o tempo necessário para a reposição da lâmina de água necessária. A comparação final entre o experimento e a produção normal utilizada pelo produtor aponta um ganho significativo no consumo de água e de energia elétrica. O controle microcontrolado além de contribuir para a diminuição do consumo dos recursos hídricos e energia elétrica, também proporcionou uma economia na manutenção dos equipamentos instalados. Com isso, chega-se a apresentar uma possibilidade de ganho econômico maior contribuindo para a melhoria de vida dos pequenos produtores familiares melhorando seus indicadores sócio-econômicos.