Wireless sensor network (WSN) technology has gained significant importance due to its potential support for a wide range of applications. Most of the WSN applications consist of a large numbers of distributed nodes that work together to achieve common objects. Running a large number of nodes requires an efficient mechanism to bring them all together in order to form a multi-hop wireless network that can accomplish some specific tasks. Even with recent developments made in WSN technology, numbers of important challenges still stand as vulnerabilities for WSNs, including energy waste sources, synchronisation leaks, low network capacity and self-configuration difficulties. However, energy efficiency remains the priority challenging problem due to the scarce energy resources available in sensor nodes. These concerns are managed by medium access control (MAC) layer protocols. MAC protocols designed specifically for WSN have an additional responsibility of managing radio activity to conserve energy in addition to the traditional functions. This thesis presents advanced research work carried out in the context of saving energy whilst achieving the desired network performance. Firstly the thesis contributes by proposing Overlapped Schedules for MAC layer, in which the schedules of the neighbour clusters are overlapped by introducing a small shift time between them, aiming to compensate the synchronisation errors. Secondly, this thesis proposed a modified architecture derived from S-MAC protocol which significantly supports higher traffic levels whilst achieving better energy efficiency. This is achieved by applying a parallel transmission concept on the communicating nodes. As a result, the overall efficiency of the channel contention mechanism increases and leads to higher throughput with lower energy consumption. Finally, this thesis proposed the use of the Adaptive scheme on Border Nodes to increase the power efficiency of the system under light traffic load conditions. The scheme focuses on saving energy by forcing the network border nodes to go off when not needed. These three contributions minimise the contention window period whilst maximising the capacity of the available channel, which as a result increase network performance in terms of energy efficiency, throughput and latency. The proposed system is shown to be backwards compatible and able to satisfy both traditional and advanced applications. The new MAC protocol has been implemented and evaluated using NS-2 simulator, under different traffic loads and varying duty cycle values. Results have shown that the proposed solutions are able to significantly enhance the performance of WSNs by improving the energy efficiency, increasing the system throughput and reducing the communication delay.

Master of Science / Department of Civil Engineering / Kyle Riding / Over the past few years, state governments and entities have become concerned with energy consumption and efficiency at their facilities. The Department of Energy has become increasingly involved in energy code enforcement, and has established initiatives to help states monitor and improve energy consumption. In order to reduce energy consumption and increase building efficiency, facilities must be compared to a baseline building and changes made accordingly. The thesis objectives are to establish a process that all states and state-funded facilities can follow that determines the baseline, establish an energy auditing procedure, and recommend monitoring techniques. In addition, this report documents a procedure developed to make recommendations for improvements and select building and equipment upgrades based and return on investment calculations. The procedures and processes established are designed so that any employee, especially non-engineers, can accomplish changes that will improve facility energy efficiency. In order to develop simplified energy auditing procedures for large and dispersed organizations, a literature review of prevalent energy codes and standards was conducted, as well as documents outlining energy audit procedures. An energy audit workbook outlining a simplified auditing procedure was created. Six KDOT facilities were audited using the procedure as part of the case study. The audit results were then used to determine practical economic calculations and determine viable improvements that reduce energy consumption. As a result of this research and case study, a simplified energy audit procedure was created. This procedure was developed to include selecting a baseline of requirements, conducting an energy audit, and selecting viable improvements using economics. All of these procedures are able to be executed by any state employee, specifically those at the facilities who may not be engineers.

In this thesis, our objective is to improve the energy efficiency and load balance for wireless networks. We first study the relationships between the base station (BS) on/off operation and traffic distribution. A cooperative power saving method called clustering BS-off (CBSO) scheme is proposed. Instead of adopting a unified and consistent BS-off scheme in the whole network, the proposed centralized and distributed CBSO schemes can adaptively group BSs in several clusters based on the traffic fluctuations with space and time. Second, to further improve the network load balance and energy efficiency in distributed manner, we propose a power efficient self-organized virtual small networking (VSN) protocol. A heuristic firefly algorithm is applied to arrange the BSs' operation in small groups based on the traffic level. By jointly considering the load balance, the effectiveness of the proposed algorithm is demonstrated based on the average and min-max traffic levels of BSs' groups. Finally, the importance of detailed BS operation between active and sleep modes is considered. The operating procedure of femtocell base station, i.e., HeNB, is modeled as an MAP/PH/1/k queueing system. Such queueing analysis particularly focuses on the HeNB vacation process with user priorities. The HeNB's power on/off scheme is modeled as alternative service and vacation periods. The hybrid access is regarded as high and low priority users in the queuing system. We further propose the adaptive service rate and vacation length (ASV) method, so that the HeNB can work in a more energy-efficient way while satisfying QoS requirements such as blocking probability and users waiting time. Simulation results show the effectiveness of the proposed strategies and the overall network energy efficiency can be improved significantly. / October 2016

As an energy-efficient alternative in cold climate countries such as Sweden, low-temperature heating (LTH) technology has shown promising advantages and shortcuts to contribute to the efficiency of heat supply, as well as to the overall sustainability of building performance. The goal of this thesis is to contribute to the development of methodologies and modeling tools to support sustainable retrofitting in the Swedish housing stock. A combination of three integrated modeling techniques was developed. The main focus of this work was implementing LTH in retrofitting practice. The principle of the developed methods can be regarded as a top-down approach, underpinning the general definition of LTH and sustainability criteria. It was found that a preliminary compilation and investigation of the building typology could simplify the retrofitting decision-making. Also, 36–54% of final energy savings could be achieved in studied housing archetypes by effective energy retrofitting. Combining LTH radiators with ventilation heat recovery showed the largest contributions. Below 30 W/m2 (12 W/ m3) heating demand, both radiators (ventilation radiators and baseboard radiator) could work as LTH. These reduced supply temperatures further improved the COP of air-source heat pumps by approximately 12% - 18%. For retrofitting of conventional radiators, there was no concrete evidence to support Type 22 having higher thermal efficiency than Type 21, for the Swedish climate and heating seasons. The achievements and full potential of implementing LTH in retrofitting were found to require not only efficient radiators, but also a well-designed package – insulation, piping, pumping and energy supply system - that suited the current heating demand of the building, given the local climate condition. However, it should also be highlighted that retrofitting incorporating all evaluated measures would not always yield higher long-term economic profits among different archetypes. It is important to find the trade-off between cost-effectiveness and energy savings in similar archetypes - instead of using a “one size fits all” types of solution. For conventional retrofit measures, such as insulations of building envelopes, it was necessary to evaluate the embodied energy during the whole retrofitting process. / Den ökande relativa energianvändningen i bostadsbyggnader i stadsmiljö har lett till högre krav på energieffektivit och hållbar omvandling av redan existerande bostadsbyggnader. En viktig förutsättning för att genomföra en sådan omvandling är att först utveckla metoder för hur effektiva beslut om renovering ska ske, samt att utveckla teknik för hållbar renovering. Lågtemperatursuppvärmning (LTH) har visat sig ha fördelar som ett hållbart och energieffektivt alternativ i länder med kallt klimat som Sverige. Metoden bidra till ökad effektivitet för uppvärmning och minskade energibehov för byggnadskomplexet. Det saknas fortfarande flera steg för hur man ska utforma modelleringsverktyg och utveckla kostnadseffektiva metoder för beslutsfattning och implementering av LTH i redan existerande byggnader. Dessutom försvårar avsaknaden av dessa verktyg och metoder genomförandet av kritiska utvärderingar av renoveringsalternativ utifrån hållbarhets- och effektivitetssynpunkt med huvudfokus på energibesparingspotential, miljöpåverkan och nöjdhet hos de boende. Dessa frågor undersöks i denna avhandling i samband med renovering av existerande bostadsbyggnader i Sverige.   Målet är att bidra till utvecklingen av metoder och modelleringsverktyg för hållbar renovering. Under arbetet utvecklades tre modelleringskoncept som integrerats med varandra och som svarar för olika steg i renoveringsmodelleringen. Huvudfokus i arbetet var att göra LTH till en del av vår renoveringspraxis. De renoveringsalternativ som studerats i arbetet inkluderar renovering av klimatskalet för att minska energibehovet samt implementering av LTH-radiatorer och där påvisa deras fördelar för valt primärenergisystem. Analysen omfattar även den sammantagna effekten av och de ömsesidiga beroenden som föreligger mellan olika renoveringsåtgärder. Här utvecklade metoder kan sägas följa en ”uppifrån och ner” strategi och stärker LTH som ett uppvärmningsalternativ som uppfyller hållbarhetskriterier.   Avhandlingen visar att effektiv renovering av energisystem kan minska det slutliga energibehovet med 36-54 % i de studerade byggnadstyperna. Kombinationen av LTH-radiatorer med värmeåtervinning från ventilation gav de allra största positiva bidragen. LTH-radiatorerna (ventilationsradiatorer och värmelister) fungerade som lågtemperatursuppvärmning vid uppvärmningsbehov under 30 W/m2 (12 W/ m3) och som ultra-lågtemperaturuppvärmning vid uppvärmningsbehov under 10 W/m2 (4 W/ m3). De låga framledningstemperaturer som leds till LTH-radiatorer bidrar dessutom till att öka COP (värmefaktorn) för luftvärmepumpar med 12 – 18 %, jämfört med traditionella radiatorer med lika stor värmeavgivande area. Något konkret stöd fanns inte för att Typ 22-radiatorer (dubbel konvektionsplåt) skulle ha högre värmeeffektivitet än Typ 21-radiatorer (enkel konvektionsplåt) för svenska klimatetförhållanden. Ökat antal konvektorplåtar visade sig alltså inte nödvändigtvis leda till ökad värmeeffektivitet. Tröskelvärdet för när Typ 11-radiatorer (enkel panel) presterar sämre än den mest effektiva radiatortypen, Typ 21-radiatorer (dubbel panel) som även har bättre exergiprestanda, visade sig vara ett värmebehov av 480 W/rum. För att uppnå full potential för LTH-radiatorer som renoveringsalternativ visade det sig utöver mer effektiva radiatorer även behövas ett välutformat system av rör, pumpar och energitillförsel, anpassade till byggnadens värmebehov före renovering vid rådande klimat.   Renovering som inkluderar alla möjliga alternativ leder inte alltid till högre långsiktig ekonomisk avkastning. Det är viktigt att finna en balans mellan kostnadseffektivitet och energibesparing för likande byggnadstyper, i stället för att utveckla en enda lösning som ska passa överallt. För traditionella renoveringsalternativ, så som isolering, var det nödvändigt att utvärdera den inbäddade energin under hela renoveringsprocessen. Stor risk för överskattad hållbarhet föreligger om man inte beaktar detta. / <p>QC 20160929</p> / D6559

<p>The dissertation consists of three chapters related to the low-price guarantee marketing strategy and energy efficiency analysis. The low-price guarantee is a marketing strategy in which firms promise to charge consumers the lowest price among their competitors. Chapter 1 addresses the research question "Does a Low-Price Guarantee Induce Lower Prices'' by looking into the retail gasoline industry in Quebec where there was a major branded firm which started a low-price guarantee back in 1996. Chapter 2 does a consumer welfare analysis of low-price guarantees to drive police indications and offers a new explanation of the firms' incentives to adopt a low-price guarantee. Chapter 3 develops the energy performance indicators (EPIs) to measure energy efficiency of the manufacturing plants in pulp, paper and paperboard industry.</p><p>Chapter 1 revisits the traditional view that a low-price guarantee results in higher prices by facilitating collusion. Using accurate market definitions and station-level data from the retail gasoline industry in Quebec, I conducted a descriptive analysis based on stations and price zones to compare the price and sales movement before and after the guarantee was adopted. I find that, contrary to the traditional view, the stores that offered the guarantee significantly decreased their prices and increased their sales. I also build a difference-in-difference model to quantify the decrease in posted price of the stores that offered the guarantee to be 0.7 cents per liter. While this change is significant, I do not find the response in comeptitors' prices to be significant. The sales of the stores that offered the guarantee increased significantly while the competitors' sales decreased significantly. However, the significance vanishes if I use the station clustered standard errors. Comparing my observations and the predictions of different theories of modeling low-price guarantees, I conclude the empirical evidence here supports that the low-price guarantee is a simple commitment device and induces lower prices. </p><p>Chapter 2 conducts a consumer welfare analysis of low-price guarantees to address the antitrust concerns and potential regulations from the government; explains the firms' potential incentives to adopt a low-price guarantee. Using station-level data from the retail gasoline industry in Quebec, I estimated consumers' demand of gasoline by a structural model with spatial competition incorporating the low-price guarantee as a commitment device, which allows firms to pre-commit to charge the lowest price among their competitors. The counterfactual analysis under the Bertrand competition setting shows that the stores that offered the guarantee attracted a lot more consumers and decreased their posted price by 0.6 cents per liter. Although the matching stores suffered a decrease in profits from gasoline sales, they are incentivized to adopt the low-price guarantee to attract more consumers to visit the store likely increasing profits at attached convenience stores. Firms have strong incentives to adopt a low-price guarantee on the product that their consumers are most price-sensitive about, while earning a profit from the products that are not covered in the guarantee. I estimate that consumers earn about 0.3% more surplus when the low-price guarantee is in place, which suggests that the authorities should not be concerned and regulate low-price guarantees. In Appendix B, I also propose an empirical model to look into how low-price guarantees would change consumer search behavior and whether consumer search plays an important role in estimating consumer surplus accurately.</p><p>Chapter 3, joint with Gale Boyd, describes work with the pulp, paper, and paperboard (PP&PB) industry to provide a plant-level indicator of energy efficiency for facilities that produce various types of paper products in the United States. Organizations that implement strategic energy management programs undertake a set of activities that, if carried out properly, have the potential to deliver sustained energy savings. Energy performance benchmarking is a key activity of strategic energy management and one way to enable companies to set energy efficiency targets for manufacturing facilities. The opportunity to assess plant energy performance through a comparison with similar plants in its industry is a highly desirable and strategic method of benchmarking for industrial energy managers. However, access to energy performance data for conducting industry benchmarking is usually unavailable to most industrial energy managers. The U.S. Environmental Protection Agency (EPA), through its ENERGY STAR program, seeks to overcome this barrier through the development of manufacturing sector-based plant energy performance indicators (EPIs) that encourage U.S. industries to use energy more efficiently. In the development of the energy performance indicator tools, consideration is given to the role that performance-based indicators play in motivating change; the steps necessary for indicator development, from interacting with an industry in securing adequate data for the indicator; and actual application and use of an indicator when complete. How indicators are employed in EPA’s efforts to encourage industries to voluntarily improve their use of energy is discussed as well. The chapter describes the data and statistical methods used to construct the EPI for plants within selected segments of the pulp, paper, and paperboard industry: specifically pulp mills and integrated paper & paperboard mills. The individual equations are presented, as are the instructions for using those equations as implemented in an associated Microsoft Excel-based spreadsheet tool.</p> / Dissertation

<div><p>Modern mobile devices have numerous ephemeral tasks. These tasks are driven by background activities, such as push notifications and sensor readings. In order to execute these tasks, the whole platform has to periodically wake up beforehand, and go to sleep afterwards. During this process, the OS kernel operates on power state of various IO devices, which has been identified as the bottleneck for energy efficiency. To this end, we want to offload this kernel phase to a more energy efficient, microcontroller level core, named peripheral core.</p></div><div><p> </p></div><div><p>To execute commodity OS on a peripheral core, existing approaches either require much engineering effort or incur high execution cost. Therefore, we proposed a new OS model called transkernel. By utilizing cross-ISA dynamic binary translation (DBT) technique, transkernel creates a virtualized environment on the peripheral core. It relies on a small set of stable interfaces. It is specialized for frequently executed kernel path. It exploits ISA similarities to reduce DBT overhead.</p></div><div><p> </p></div><div><p>We implement a transkernel model on ARM platform. With novel design and optimization, we demonstrate that a transkernel can gain energy efficiency. Moreover, it provides a new OS design to harness heterogeneous SoCs.</p></div>

In this dissertation, power allocation approaches considering path loss, shadowing, and Rayleigh and Nakagami-m fading are proposed. The goal is to improve power consumption, and energy and throughput efficiency based on user target signal to interference plus noise ratio (SINR) requirements and an outage probability threshold. First, using the moment generating function (MGF), the exact outage probability over Rayleigh and Nakagami-m fading channels is derived. Then upper and lower bounds on the outage probability are derived using the Weierstrass, Bernoulli and exponential inequalities. Second, the problem of minimizing the user power subject to outage probability and user target SINR constraints is considered. The corresponding power allocation problems are solved using Perron-Frobenius theory and geometric programming (GP). A GP problem can be transformed into a nonlinear convex optimization problem using variable substitution and then solved globally and efficiently by interior point methods. Then, power allocation problems for throughput maximization and energy efficiency are proposed. As these problems are in a convex fractional programming form, parametric transformation is used to convert the original problems into subtractive optimization problems which can be solved iteratively. Simulation results are presented which show that the proposed approaches are better than existing schemes in terms of power consumption, throughput, energy efficiency and outage probability. Prioritized cell association and power allocation (CAPA) to solve the load balancing issue in heterogeneous networks (HetNets) is also considered in this dissertation. A Hetnet is a group of macrocell base stations (MBSs) underlaid by a diverse set of small cell base stations (SBSs) such as microcells, picocells and femtocells. These networks are considered to be a good solution to enhance network capacity, improve network coverage, and reduce power consumption. However, HetNets are limited by the disparity of power levels in the different tiers. Conventional cell association approaches cause MBS overloading, SBS underutilization, excessive user interference and wasted resources. Satisfying priority user (PU) requirements while maximizing the number of normal users (NUs) has not been considered in existing power allocation algorithms. Two stage CAPA optimization is proposed to address the prioritized cell association and power allocation problem. The first stage is employed by PUs and NUs and the second stage is employed by BSs. First, the product of the channel access likelihood (CAL) and channel gain to interference plus noise ratio (GINR) is considered for PU cell association while network utility is considered for NU cell association. Here, CAL is defined as the reciprocal of the BS load. In CAL and GINR cell association, PUs are associated with the BSs that provide the maximum product of CAL and GINR. This implies that PUs connect to BSs with a low number of users and good channel conditions. NUs are connected to BSs so that the network utility is maximized, and this is achieved using an iterative algorithm. Second, prioritized power allocation is used to reduce power consumption and satisfy as many NUs with their target SINRs as possible while ensuring that PU requirements are satisfied. Performance results are presented which show that the proposed schemes provide fair and efficient solutions which reduce power consumption and have faster convergence than conventional CAPA schemes. / Graduate

The crisis of the mortgage market and the mortgage-backed security (MBS) market in 2008 had dramatic negative effects in dragging down all of the economy on a worldwide scale. Many researches have, therefore, attempted to explore the influencing factors on mortgage default risk. This project, in cooperation with the company EnerScore, revolves around discovering a correlation between portfolios of mortgages to underlying energy expenditures. EnerScore€™s core product provides an internal dataset related to home energy efficiency for American homes and gives their corresponding home energy efficiency rating to every home, which is called an €œEnerScore.€� This project involves discovering a correlation between default within portfolios of mortgages based on underlying energy expenditures. The goal is to show that energy efficient homes potentially have lower default risks than standard homes because the homes which lack energy efficiency are associated with higher energy costs. This leaves less money to make the mortgage payment, and thereby increases default risk. The first phase of this project involves finding a foreclosure dataset that will be used to design the quantitative model. Due to limited availability and constraints related to default data, Google search query data is used to develop a broad based and real-time index of mortgage default risk and establish a meaningful scientific correlation. After analyzing several statistical models to explore this correlation, the regression tree model showed that the EnerScore is a strong predictor for mortgage default risk when using city-level mortgage default risk data and EnerScore data.

<div>Deep Neural Networks (DNNs) have emerged as the state-of-the-art technique in a wide range of machine learning tasks for analytics and computer vision in the next generation of embedded (mobile, IoT, wearable) devices. Despite their success, they suffer from high energy requirements both in inference and training. In recent years, the inherent error resiliency of DNNs has been exploited by introducing approximations at either the algorithmic or the hardware levels (individually) to obtain energy savings while incurring tolerable accuracy degradation. We perform a comprehensive analysis to determine the effectiveness of cross-layer approximations for the energy-efficient realization of large-scale DNNs. Our experiments on recognition benchmarks show that cross-layer approximation provides substantial improvements in energy efficiency for different accuracy/quality requirements. Furthermore, we propose a synergistic framework for combining the approximation techniques. </div><div>To reduce the training complexity of Deep Convolutional Neural Networks (DCNN), we replace certain weight kernels of convolutional layers with Gabor filters. The convolutional layers use the Gabor filters as fixed weight kernels, which extracts intrinsic features, with regular trainable weight kernels. This combination creates a balanced system that gives better training performance in terms of energy and time, compared to the standalone Deep CNN (without any Gabor kernels), in exchange for tolerable accuracy degradation. We also explore an efficient training methodology and incrementally growing a DCNN to allow new classes to be learned while sharing part of the base network. Our approach is an end-to-end learning framework, where we focus on reducing the incremental training complexity while achieving accuracy close to the upper-bound without using any of the old training samples. We have also explored spiking neural networks for energy-efficiency. Training of deep spiking neural networks from direct spike inputs is difficult since its temporal dynamics are not well suited for standard supervision based training algorithms used to train DNNs. We propose a spike-based backpropagation training methodology for state-of-the-art deep Spiking Neural Network (SNN) architectures. This methodology enables real-time training in deep SNNs while achieving comparable inference accuracies on standard image recognition tasks.</div>

THE TITLE OF THE DIPLOMA THESIS AND ABSTRACT TITLE: The Legislation Governing Energy Efficiency in the European Union ABSTRACT: The European Union's energy policy has undergone a major transformation over the last few years. The interest in ensuring sustainability, self-sufficiency, competitiveness and secure energy supplies leads to deeper energy integration among Member States. High energy efficiency is an ideal tool for achieving these particular objectives because its basic principle is to provide more services while using the same or even less energy. As a result, a variety of conceptual instruments and relevant legislation have been revised over the last few years, which was accompanied by a conflict of interest between various stakeholders and the adoption of less than ideal compromise solutions. This diploma thesis aims to evaluate the current legislation on energy efficiency in the European Union, including its development. The thesis is divided into three parts, the first of which represents the initial theoretical basis that aims to define the basic concepts and indicators of energy efficiency. The second part deals with the strong link between environmental protection and energy efficiency while emphasizing the importance of fundamental environmental principles that are reflected in the...