To see the other types of publications on this topic, follow the link: Sleep mode.
Dissertations / Theses on the topic 'Sleep mode'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Sleep mode.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Baldini, Federico. "Ottimizzazione della scansione wifi: Sleep Mode." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5014/.
Full text
2
Twayej, Wasan Adnan. "Network performance evaluation for M2M WSN and SDN based on IOT applications." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17020.
Full textAbstract:
This thesis introduces different mechanisms for energy efficiency in Wireless Sensor Networks (WSNs) along with maintaining high levels of Network Performance (N.P) with reduced complexity. Firstly, a Machine-to-Machine (M2M) WSN is arranged hierarchically in a fixed infrastructure to support a routing protocol for energy-efficient data transmission among terminal nodes and sink nodes via cluster heads (CHs). A Multi-Level Clustering Multiple Sinks (MLCMS) routing protocol with the IPv6 protocol over Low Wireless Personal Area Networks (6LoWPAN) is proposed to prolong network lifetime. The simulation results show 93% and 147% enhancement in energy efficiency and system lifespan compared to M-LEACH and LEACH, respectively. By utilising 6LoWPAN in the proposed system, the number of packets delivered increases by 7%, with higher accessibility to the M2M nodes and a substantial extension of the network is enabled. Secondly, an adaptive sleep mode with MLCMS for an efficient lifetime of M2M WSN is introduced. The time period of the active and asleep modes for the CHs has been considered according to a mathematical function. The evaluations of the proposed scheme show that the lifetime of the system is doubled and the end-to-end delay is reduced by half. Thirdly, enhanced N.P is achieved through linear integer-based optimisation. A Self-Organising Cluster Head to Sink Algorithm (SOCHSA) is proposed, hosting Discrete Particle Swarm Optimisation (DPSO) and Genetic Algorithm (GA) as Evolutionary Algorithms (EAs) to solve the N.P optimisation problem. N.P is measured based on load fairness and average ratio residual network energy. DPSO and GA are compared with the Exhaustive Search (ES) algorithm to analyse their performances for each benchmark problem. Computational results prove that DPSO outperforms GA regarding complexity and convergence, thus it is best suited for a proactive IoT network. Both algorithms achieved optimum N.P evaluation values of 0.306287 and 0.307731 in the benchmark problems P1 and P2, respectively, for two and three sinks. The proposed mechanism satisfies different N.P requirements of M2M traffic by instant identification and dynamic rerouting to achieve optimum performance. Finally, a Power Model (PM) is essential to investigate the power efficiency of a system. Hence, a Power Consumption (PC) profile for SDN-WISE, based on IoT is developed. The outcomes of the study offer flexibility in managing the structure of an M2M system in IoT. They enable controlling the provided Network Quality of Service (NQoS), precisely by achieving physical layer throughput. In addition, it provides a schematic framework for the Application Quality of Service (AQoS), specifically, the IoT data stream payload size (from the PC point of view). It is composed of two essential parts, i.e., control signalling and data traffic PCs and the results show a 98% PC of the data plane in the total system power, whereas the control plane PC is only 2%, with a minimum Transmission Time Interval (TTI) (5 sec) and a maximum payload size of 92 Bytes.
3
Lin, Yu. "A Two-Mode Synchronous Buck Converter for Low-Power Devices with the Sleep Mode." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/72870.
Full textAbstract:
The power consumption of smart camera in car black box varies significantly between light load and heavy load. The high efficiency voltage regulator is necessary in prolong the life of smart camera battery. Since the smart camera only recording the video when car is driving, the most time of the smart camera works in the sleep mode. Hence the light load efficiency is important in this application, however, conventional buck converter usually have high efficiency at heavy load but poor efficiency at light load. To increase the light load efficiency of buck converter, this research continues Yeago's two phase buck converter with optimum phase selection control and Zhao's two mode buck converter to further improve the light load efficiency for the target application.
With 5V input voltage and 1.2V output voltage, the proposed two-mode synchronous buck converter can supply the load power from 12mW to 1.44W. To improve the light load efficiency of conventional buck converter, the proposed design applied Wei's baby buck concept to provide another light load power stage to reduce the switching loss and driving loss at light load. Then, the variable frequency ripple-based constant on-time control with discontinuous conduction mode (DCM) in light load is applied to the baby-buck mode to reduce the switching frequency to further reduce the switching loss. Also, the baby-buck mode uses the synchronous buck topology to remove the diode in asynchronous converter to increase the efficiency at light load. Finally, a sensorless mode selector remove the sensing resistor in power stage to increase the efficiency for entire load range, especially for the heavy load. The mode selector can select the optimum mode for different load condition, and the opposite mode would completely shut down to save the loss.
The proposed design is implement in CMOS 0.25um technology. The proposed monolithic buck converter which include the power stage of heavy buck mode, baby-buck mode and the controller is fabricated. The measurement result shows the close loop efficiency varies from 70%-83% toward the entire load range.Master of Science
4
Fiammengo, Martina. "Sleep mode scheduling technique for energy saving in TDM-PONs." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-31062.
Full textAbstract:
Nowadays energy efficiency of telecommunication networks is receiving more attention than in the past for natural reasons. The situation is critical especially for access networks that typically include many end-user devices that consume a lot of energy. This thesis proposes a novel sleep mode technique for TDM-PONs that turns off the ONUs (placed at the customer premises) when certain traffic conditions are verified. The objective is to achieve an improved energy efficiency without impacting too much the Quality of Service perceived by end-users. The whole operation is managed at the OLT (placed at the provider central office) and the length of the sleep time periods is computed employing a statistical method. An approximated version has been implemented in hardware for proof of concept. The obtained results show that the proposed sleep mode technique has good performances for some test cases while it should be avoided for others.
5
ARAUJO, Ivanes Lian Costa. "Algoritmo de Sleep Mode para redes LTE em conectividade dual." Universidade Federal do Pará, 2015. http://repositorio.ufpa.br/jspui/handle/2011/7491.
Full textAbstract:
Submitted by camilla martins (camillasmmartins@gmail.com) on 2017-01-27T17:41:03Z
No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Dissertacao_AlgoritmoSleepMode.pdf: 1544032 bytes, checksum: f8b4ae8a434371d60fab4dac15eef84f (MD5)Approved for entry into archive by Edisangela Bastos (edisangela@ufpa.br) on 2017-01-30T14:11:21Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AlgoritmoSleepMode.pdf: 1544032 bytes, checksum: f8b4ae8a434371d60fab4dac15eef84f (MD5)
Made available in DSpace on 2017-01-30T14:11:21Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AlgoritmoSleepMode.pdf: 1544032 bytes, checksum: f8b4ae8a434371d60fab4dac15eef84f (MD5) Previous issue date: 2015-09-18
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Este trabalho realiza um minucioso estudo dos ganhos da conectividade dual em redes Long Term Evolution (LTE) e propõe um algoritmo de "sleep mode" que potencializa a eficiência da rede neste contexto. Dentre os algoritmos de "sleep mode" em conectiviclade dual da literatura, nenhum realiza abordagem envolvendo a capacidade do "backhaul" das "small cells" para a decisão da ativação das mesmas. A carência de um processo de "sleep mode" que possa abranger o "backhaul" pode resultar em gargalos na rede, maior latência e perda de pacotes. Dessa forma, o algoritmo proposto lança luz a um aspecto relevante na conjuntura de redes LTE, além de quantificar os benefícios advindos não apenas do uso do algoritmo, mas da conectiviclade dual em si. Para a análise destes benefícios, o estudo foi elaborado a partir de diversas simulações feitas no "software" Riverbect Modeler, embasadas em parâmetros do 3rd Generation Partnership Project (3GPP) e artigos atuais da área. Os resultados das simulações atestam que menores níveis de atraso podem ser alcançados com a conectiviclade dual, e ainda potencializados com o uso do algoritmo proposto, que contribui para o uso mais eficiente dos recursos da rede também do ponto de vista energético. Além destes ganhos, são analisados resultados em relação ao tráfego no "backhaul" tanto das "small cells" quanto do núcleo da rede. O conjunto destes resultados aponta diversas vantagens do uso de conectividade dual e do algoritmo proposto neste trabalho, em redes LTE.
This work presents the analysis of the benefits of dual connectivity in Long Term Evo- lution (LTE) networks, and proposes a sleep mode algorithm in order to increase even more the network efficiency. Among the sleep mode algorithms for dual connectivity in literature, none makes an approach regarding the small cells backhaul capacity for the activation decision of these small cells. The lack of an appropriate sleep mode process that takes backhaul issues into consideration can lead to network bottlenecks, greater latency and packet drops. For this reason, the algorithm highlights relevant aspects in LTE networks, and quantifies the benefits obtained not only by the use of the algorithm but also by the use of the dual connectivity itself. To accomplish this goal, several simulations were performed with the software Riverbed Mode- ler, based on 3rd Generation Partnership Project (3GPP) parameters and papers from this area. The simulation results show that lower delay levels can be achieved with the use of dual con- nectivity, and even lower results can be obtained with the use of the proposed algorithm, which also contributes to a more energy efficient usage of network resources. Furthermore, results regarding backhaul traffic in the core network and among small cells are also analyzed. The results, in general, show several advantages of dual connectivity and the proposed algorithm in LTE networks.
6
Peters, Henning [Verfasser]. "Default Mode Network Changes during NREM Sleep – a Combined EEG/fMRI Study / Henning Peters." München : Verlag Dr. Hut, 2011. http://d-nb.info/1018981756/34.
Full text
7
van, Coppenhagen Robert Lindenberg, and robert vancoppenhagen@dsto defence gov au. "On the Coordinated Use of a Sleep Mode in Wireless Sensor Networks: Ripple Rendezvous." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070122.145741.
Full textAbstract:
It is widely accepted that low energy consumption is the most important requirement when designing components and systems for a wireless sensor network (WSN). The greatest energy consumer of each node within a WSN is the radio transceiver and as such, it is important that this component be used in an extremely energy e±cient manner. One method of reducing the amount of energy consumed by the radio transceiver is to turn it off and allow nodes to enter a sleep mode. The algorithms that directly control the radio transceiver are traditionally grouped into the Medium Access Control (MAC) layer of a communication protocol stack. This thesis introduces the emerging field of wireless sensor networks and outlines the requirements of a MAC protocol for such a network. Current MAC protocols are reviewed in detail with a focus on how they utilize this energy saving sleep mode as well as performance problems that they suffer from. A proposed new method of coordinating the use of this sleep mode between nodes in the network is specifed and described. The proposed new protocol is analytically compared with existing protocols as well as with some fundamental performance limits. The thesis concludes with an analysis of the results as well as some recommendations for future work.
8
Al-Baadani, Faris. "A novel location energy sleep mode saving algorithm (LESMS) based on clustering for WSN." Thesis, Anglia Ruskin University, 2017. http://arro.anglia.ac.uk/703767/.
Full textAbstract:
Due to sensors being distributed in an ad-hoc manner and their ability to sense different environmental conditions, Wireless Sensor Networks (WSNs) have become very popular in various real time applications and Internet of Things (IoT). The WSN is widely used in monitoring harsh environments and taking decisions on the basis of collected reports. Clustering in WSNs is a proven technique to avoid redundant transmissions to the sink. This allows for better utilisation of scarce network resources such as energy. Most of the clustering algorithms proposed in the literature involve a high number of message exchanges, which results in unnecessary energy consumption. This thesis proposes a new cluster head (CH) selection protocol based on the average energy and the location of the nodes. Five different approaches for the CH selection were examined and were statistically analysed: (i) random selection; (ii) selecting the node closest to the arithmetic mean node coordinate; (iii) selecting the node at the medoid coordinate; (iv) selecting the node nearest to the region centre; (v) selecting node nearest the BS. The mean distance of all nodes to their local CH was the dependent variable. Furthermore, three node grouping schemes were further studied and compared to the k-means clustering: (i) all nodes in the same group; (ii) dividing the sensor field into four rectangular quadrants and allocating nodes accordingly; (iii) dividing the sensor field into eight sectors and allocating nodes accordingly. T-Test and one way ANOVA were used for the P-value analysis. The sleeping mode technique was implemented. The residual energy level was then used as a main factor, for the CH selection. The average energy value and the minimum distance value both became the weighting factors to select the CH. The Assistant Cluster Head (ACH) technique was introduced to the LESMS to act as a backup system in case of the CH power levels reach critical levels or total loss of the CH node . Finally, a new technique was introduced to perform a periodic CH health check-up to monitors the energy level of the CH. Simulations were performed using MATLAB and Network Simulator 2 (NS2). Results show that selecting the node closest to the arithmetic mean as CH has outcome other approaches. Also, the sensor field dividing scheme has a shorter distance of all the nodes compared to the k-mean. The LESMS, under a mixture of workload environments resulted in low power consumption, low delay, low packet drop, and low control overhead. It also showed high throughput, high packet delivery ratio (PDR) and an increase in the total residual energy.
9
Al-Baadani, Faris. "A novel location energy sleep mode saving algorithm (LESMS) based on clustering for WSN." Thesis, Anglia Ruskin University, 2017. https://arro.anglia.ac.uk/id/eprint/703767/1/Al-Baadani_2017.pdf.
Full textAbstract:
Due to sensors being distributed in an ad-hoc manner and their ability to sense different environmental conditions, Wireless Sensor Networks (WSNs) have become very popular in various real time applications and Internet of Things (IoT). The WSN is widely used in monitoring harsh environments and taking decisions on the basis of collected reports. Clustering in WSNs is a proven technique to avoid redundant transmissions to the sink. This allows for better utilisation of scarce network resources such as energy. Most of the clustering algorithms proposed in the literature involve a high number of message exchanges, which results in unnecessary energy consumption.
This thesis proposes a new cluster head (CH) selection protocol based on the average energy and the location of the nodes. Five different approaches for the CH selection were examined and were statistically analysed: (i) random selection; (ii) selecting the node closest to the arithmetic mean node coordinate; (iii) selecting the node at the medoid coordinate; (iv) selecting the node nearest to the region centre; (v) selecting node nearest the BS. The mean distance of all nodes to their local CH was the dependent variable. Furthermore, three node grouping schemes were further studied and compared to the k-means clustering: (i) all nodes in the same group; (ii) dividing the sensor field into four rectangular quadrants and allocating nodes accordingly; (iii) dividing the sensor field into eight sectors and allocating nodes accordingly. T-Test and one way ANOVA were used for the P-value analysis.
The sleeping mode technique was implemented. The residual energy level was then used as a main factor, for the CH selection. The average energy value and the minimum distance value both became the weighting factors to select the CH. The Assistant Cluster Head (ACH) technique was introduced to the LESMS to act as a backup system in case of the CH power levels reach critical levels or total loss of the CH node .
Finally, a new technique was introduced to perform a periodic CH health check-up to monitors the energy level of the CH. Simulations were performed using MATLAB and Network Simulator 2 (NS2). Results show that selecting the node closest to the arithmetic mean as CH has outcome other approaches. Also, the sensor field dividing scheme has a shorter distance of all the nodes compared to the k-mean. The LESMS, under a mixture of workload environments resulted in low power consumption, low delay, low packet drop, and low control overhead. It also showed high throughput, high packet delivery ratio (PDR) and an increase in the total residual energy.
10
Tully, Carolin [Verfasser]. "Effects of sleep deprivation on resting state networks: The integrity of the default mode network and its anticorrelated network following a night of partial sleep deprivation / Carolin Tully." München : Verlag Dr. Hut, 2011. http://d-nb.info/1014848393/34.
Full text
11
Mohd, Tadza Noor Zahrinah Binti. "Energy efficient design of an adaptive switching algorithm for the iterative-MIMO receiver." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/11711.
Full textAbstract:
An efficient design dedicated for iterative-multiple-input multiple-output (MIMO) receiver systems is now imperative in our world since data demands are increasing tremendously in wireless networks. This puts a massive burden on the signal processing power especially in small receiver systems where power sources are often shared or limited. This thesis proposes an attractive solution to both the wireless signal processing and the architectural implementation design sides of the problem. A novel algorithm, dubbed the Adaptive Switching Algorithm, is proven to not only save more than a third of the energy consumption in the algorithmic design, but is also able to achieve an energy reduction of more than 50% in terms of processing power when the design is mapped onto state-of-the-art programmable hardware. Simulations are based in MatlabTM using the Monte Carlo approach, where multiple additive white Gaussian noise (AWGN) and Rayleigh fading channels for both fast and slow fading environments were investigated. The software selects the appropriate detection algorithm depending on the current channel conditions. The design for the hardware is based on the latest field programmable gate arrays (FPGA) hardware from Xilinx R , specifically the Virtex-5 and Virtex-7 chipsets. They were chosen during the experimental phase to verify the results in order to examine trends for energy consumption in the proposed algorithm design. Savings come from dynamic allocation of the hardware resources by implementing power minimization techniques depending on the processing requirements of the system. Having demonstrated the feasibility of the algorithm in controlled environments, realistic channel conditions were simulated using spatially correlated MIMO channels to test the algorithm’s readiness for real-world deployment. The proposed algorithm is placed in both the MIMO detector and the iterative-decoder blocks of the receiver. When the final full receiver design setup is implemented, it shows that the key to energy saving lies in the fact that both software and hardware components of the Adaptive Switching Algorithm adopt adaptivity in the respective designs. The detector saves energy by selecting suitable detection schemes while the decoder provides adaptivity by limiting the number of decoding iterations, both of which are updated in real-time. The overall receiver can achieve more than 70% energy savings in comparison to state-of-the-art iterative-MIMO receivers and thus it can be concluded that this level of ‘intelligence’ is an important direction towards a more efficient iterative-MIMO receiver designs in the future.
12
Saker, Louai. "Energy consumption reduction mechanisms in mobile networks." Thesis, Evry, Institut national des télécommunications, 2011. http://www.theses.fr/2011TELE0029.
Full textAbstract:
La consommation en énergie des réseaux de télécommunications a suscité un intérêt grandissant au cours des dernières années et les opérateurs mobiles cherchent des solutions innovantes pour optimiser l’efficacité énergétique. Dans cette thèse, nous nous focaliserons sur les schémas d’optimisation de la consommation d’énergie des réseaux d’accès mobiles. Nous commençons par étudier la stratégie de partage de charge qui minimise la consommation d’énergie dans la cellule tout en limitant l’impact sur la Qualité de Service. Le gain obtenu par ces algorithmes de gestion des ressources radio reste cependant limité; ceci est dû au fait que la consommation d’énergie ne dépend pas que de la charge, mais comporte une importante partie constante. Pour obtenir un gain plus important, nous proposons la mise en veille de certaines ressources du réseaux aux heures creuses où le trafic est faible, ce qui mène à des gains substantiels. Nous proposons ensuite un contrôleur de gestion de la mise en veille qui choisit l’action optimale en fonction de l’état du réseau. En effet, l’activation d’une nouvelle ressource n’est pas instantanée et un effet ping-pong peut apparaitre suite aux commandes simultanées d’activation/désactivation des ressources. Nous adaptons nos contrôleurs afin de prendre en compte ces imperfections, et nous montrons comment déduire la politique optimale. Nous étudions ensuite le cas de déploiement de petites cellules dans des réseaux hétérogènes et montrons que leur efficacité énergétique est améliorée par rapport au réseau purement macro-cellulaire, pourvu que la consommation d’énergie de petites cellules reste faible. Nous proposons ensuite un contrôleur optimal qui active/désactive les petites cellules en se basant sur des informations de trafic et de localisation des usagers. Nous considérons différents cas de figure avec une information complète, partielle ou retardée et montrons que ces schémas de mise en veille permettent d’atteindre d’importants gains de consommation d’énergieIn the recent years, more importance has been given to the energy consumption issue in telecommunication networks and mobile operators are rethinking their network design for optimizing its energy efficiency. In this thesis, we propose schemes for optimizing the energy consumption of mobile access networks. We begin by proposing energy-aware Radio Resource Management (RRM) schemes and show that a load balancing between available resources gives some energy savings. However, these gains remain small as a large part of the energy consumption is load-independent. We thus propose sleep mode schemes of resources in the network (cells or carriers) and show that they give a large gain when traffic is low. We then propose optimal sleep mode controllers that give, for each traffic scenario, the best actions to take in each state of the network. We make two observations: the first is that activating a new resource is not instantaneous, leading to QoS degradation if a conservative policy is not considered, and the second is that a ping-pong effect may appear at the frontier between two capacity regions. We adapt our controllers to take into account these imperfections, and show how to derive the optimal policy using Markov decision theory. We then extend our works to the case of small cell deployment in heterogeneous networks, composed of macro and small cells base stations. We study the capacity and power consumption of these networks and show that the energy efficiency is increased for some deployment strategies when the power consumption of small cells is low. We then propose sleep mode for small cells and develop optimal sleep/wakeup schemes based on the information on traffic load and user localization in the cell, in the cases where this information is complete, partial or delayed. We show that these sleep mode schemes achieve large energy consumption gains
13
Saker, Louai. "Energy consumption reduction mechanisms in mobile networks." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2011. http://www.theses.fr/2011TELE0029.
Full textAbstract:
La consommation en énergie des réseaux de télécommunications a suscité un intérêt grandissant au cours des dernières années et les opérateurs mobiles cherchent des solutions innovantes pour optimiser l’efficacité énergétique. Dans cette thèse, nous nous focaliserons sur les schémas d’optimisation de la consommation d’énergie des réseaux d’accès mobiles. Nous commençons par étudier la stratégie de partage de charge qui minimise la consommation d’énergie dans la cellule tout en limitant l’impact sur la Qualité de Service. Le gain obtenu par ces algorithmes de gestion des ressources radio reste cependant limité; ceci est dû au fait que la consommation d’énergie ne dépend pas que de la charge, mais comporte une importante partie constante. Pour obtenir un gain plus important, nous proposons la mise en veille de certaines ressources du réseaux aux heures creuses où le trafic est faible, ce qui mène à des gains substantiels. Nous proposons ensuite un contrôleur de gestion de la mise en veille qui choisit l’action optimale en fonction de l’état du réseau. En effet, l’activation d’une nouvelle ressource n’est pas instantanée et un effet ping-pong peut apparaitre suite aux commandes simultanées d’activation/désactivation des ressources. Nous adaptons nos contrôleurs afin de prendre en compte ces imperfections, et nous montrons comment déduire la politique optimale. Nous étudions ensuite le cas de déploiement de petites cellules dans des réseaux hétérogènes et montrons que leur efficacité énergétique est améliorée par rapport au réseau purement macro-cellulaire, pourvu que la consommation d’énergie de petites cellules reste faible. Nous proposons ensuite un contrôleur optimal qui active/désactive les petites cellules en se basant sur des informations de trafic et de localisation des usagers. Nous considérons différents cas de figure avec une information complète, partielle ou retardée et montrons que ces schémas de mise en veille permettent d’atteindre d’importants gains de consommation d’énergieIn the recent years, more importance has been given to the energy consumption issue in telecommunication networks and mobile operators are rethinking their network design for optimizing its energy efficiency. In this thesis, we propose schemes for optimizing the energy consumption of mobile access networks. We begin by proposing energy-aware Radio Resource Management (RRM) schemes and show that a load balancing between available resources gives some energy savings. However, these gains remain small as a large part of the energy consumption is load-independent. We thus propose sleep mode schemes of resources in the network (cells or carriers) and show that they give a large gain when traffic is low. We then propose optimal sleep mode controllers that give, for each traffic scenario, the best actions to take in each state of the network. We make two observations: the first is that activating a new resource is not instantaneous, leading to QoS degradation if a conservative policy is not considered, and the second is that a ping-pong effect may appear at the frontier between two capacity regions. We adapt our controllers to take into account these imperfections, and show how to derive the optimal policy using Markov decision theory. We then extend our works to the case of small cell deployment in heterogeneous networks, composed of macro and small cells base stations. We study the capacity and power consumption of these networks and show that the energy efficiency is increased for some deployment strategies when the power consumption of small cells is low. We then propose sleep mode for small cells and develop optimal sleep/wakeup schemes based on the information on traffic load and user localization in the cell, in the cases where this information is complete, partial or delayed. We show that these sleep mode schemes achieve large energy consumption gains
14
Mugume, Edwin. "Green heterogeneous cellular networks." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/green-heterogeneous-cellular-networks(e7976a91-c891-4174-abaf-18820ff1736d).html.
Full textAbstract:
Data traffic demand has been increasing exponentially and this trend will continue over theforeseeable future. This has forced operators to upgrade and densify their mobile networks toenhance their capacity. Future networks will be characterized by a dense deployment of different kinds of base stations (BSs) in a hierarchical cellular structure. However network densification requires extensive capital and operational investment which limits operator revenues and raises ecological concerns over greenhouse gas emissions. Although networks are planned to support peak traffic, traffic demand is actually highly variable in both space and time which makes it necessary to adapt network energy consumption to inevitable variations in traffic demand. In this thesis, stochastic geometry tools are used to perform simple and tractable analysis of thecoverage, rate and energy performance of homogeneous networks and heterogeneous networks(HetNets). BSs in each tier are located according to independent Poisson Point Processes(PPPs) to generate irregular topologies that fairly resemble practical deployment topologies. The homogeneous network is optimized to determine the optimal BS density and transmit power configuration that minimizes its area power consumption (APC) subject to both coverage and average rate constraints. Results show that optimal transmit power only depends on the BSpower consumption parameters and can be predetermined. Furthermore, various sleep modemechanisms are applied to the homogeneous network to adapt its APC to changes in userdensity. A centralized strategic scheme which prioritize BSs with the least number of usersenhances energy efficiency (EE) of the network. Due to the complexity of such a centralizedscheme, a distributed scheme which implements the strategic algorithm within clusters of BSsis proposed and its performance closely matches that of its centralized counterpart. It is more challenging to model the optimal deployment configuration per tier in a multi-tier HetNet. Appropriate assumptions are used to determine tight approximations of these deployment configurations that minimize the APC of biased and unbiased HetNets subject tocoverage and rate constraints. The optimization is performed for three different user associationschemes. Similar to the homogeneous network, optimal transmit power per tier also depends onBS power consumption parameters only and can also be predetermined. Analysis of the effect of biasing on HetNet performance shows appropriate biasing can further reduce the deploymentconfiguration (and consequently the APC) compared to an unbiased HetNet. In addition, biasing can be used to offload traffic from congesting and high-power macro BSs to low-power small BSs. If idle BSs are put into sleep mode, more energy is saved and HetNet EE improves. Moreover, appropriate biasing also enhances the EE of the HetNet.
15
Karlsson, Leif. "Time-synchronized wireless mesh networks using battery-powered nodes." Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-75050.
Full textAbstract:
This thesis proposes an implementation of battery-powered, time-synchronized wireless nodes that can be deployed in a wireless network topology. Wireless sensor networks are used in a wide variety of scenarios where emphasis is placed on the wireless nodes’ battery life. The main area of focus in this thesis is to examine how wireless nodes can save battery power by utilizing a deep sleep mode and wake up simultaneously using time synchronization to carry out their data communication. This was achieved by deploying five time-synchronized, battery-powered nodes in a wireless network topology. The difference in battery current draw between continuously running nodes and sleep-enabled nodes were measured, as well as the time duration needed by the nodes to successfully send their payloads and route other nodes’ data. The nodes needed between 1502 ms and 3273 ms on average to carry out their data communication, depending on where they were located in the network topology. Measurements show that sleep-enabled nodes on average draw substantially less current than continuously running nodes during a complete data communication cycle. When sleep-enabled nodes were powered by two AA batteries, an increase in battery life of up to 1800% was observed.
16
Hu, Anqiao. "Green Electronics: High Efficiency On-chip Power Management Solutions for Portable and Battery-Powered Applications." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1291144939.
Full text
17
Kleist, Anders. "Theory of super power saving circuits and configurations for mixed signal CPU for smartcard application." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2326.
Full textAbstract:
Designing an application specific integrated circuit (ASIC) must be starting with careful preparations, otherwise the chip will not be as good as possible. The theoretical studies must cover everything from the chip circuits to the application structure. In mobile applications there is extremely important that the current consumption becomes minimized because the battery power is limited. The power reductions studies must include the most power costing circuits on the chip. When the whole circuit or segments of the circuit is not in use, they must switch fast and simple into another mode that consume nearly none power. This mode is called sleep-mode. If the sleep-mode has very low leakage currents, the lifetime of the application will dramatically increase.
This report studies the most power costing circuits in smartcard application ASIC. The chip should be used to control a LCD display on the smartcard. The circuits that have been investigated are level shifters, charge pumps and LCD drivers, also sleep-mode configuration possibilities have been investigated. Other small preparing work is also included in the thesis.
18
Mead, Michael P. "Dual Effects Model of Social Control: Extending the Model to 24-Hour Health Behavior." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28590.
Full textAbstract:
The Dual Effects Model of Social Control suggests that partners can positively and negatively influence the health behaviors of their partner. However, the model fails to consider the impact of control on non-targeted health behaviors, such as sleep. The current study sought to expand this model by including sleep continuity and duration as outcomes related to control efforts targeting diet and exercise. Partner control and objective sleep data were collected via daily sleep diaries and Fitbit Charge HR. Regression models were used to test the direct and indirect effects of control on sleep duration and continuity and the extent to which affective response mediates this relationship. Negative control had a significant effect on negative affect, but not on sleep continuity or duration. Positive control had a significant effect on positive affective response, but the full mediation model was not supported. Recommendations for future research using the proposed model are discussed.
19
Yin, Weiwei. "A Mathematical Model of the Sleep-Wake Cycle." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14508.
Full textAbstract:
The daily sleep-wake cycle usually consists of three distinct states: wakefulness, non-rapid-eye-movement (NREM) and rapid-eye-movement (REM). The process of switching between different states is complex, but a common assumption is that it is regulated primarily by two processes (the circadian and the homeostatic process) via reciprocal interactions of several downstream neuron groups. These interactions not only result in often rapid transitions from one state to another, but also allow for a certain degree of bi-stability that locks the organism in a given state for some while before it switches back. In order to better understand how the behavioral states are regulated by different neuron groups, I describe how to use the S-system method for the development of a mathematical model consisting of two phases. The first phase covers the switch between wakefulness and sleep, which is controlled by the interactions between wake- and sleep-promoting neurons, whereas the second phase addresses the generation of NREM-REM alternation, which is believed to be regulated by REM-OFF and REM-ON neurons. In this set-up I interpret the circadian rhythm as external input and homeostatic regulation as a feedback controller. Both open-loop and closed-loop forms of the two-phase model are investigated and implemented. Discharging activities of the corresponding neuron groups and the switches of behavioral states are shown in the simulation results, from which we can easily identify the basic roles of wake- and sleep-promoting neurons, REM-OFF and REM-ON neurons. The special regulatory function of the neuropeptide orexin is also tested by simulation.
20
Wang, Yuehe. "Model based dynamic analysis of human sleep electroencephalogram." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/30210.
Full textAbstract:
For sleep classification, automatic electroencephalogram (EEG) interpretation techniques are of interest because they are labour saving, in contrast to manual (visual) methods. More importantly, some automatic methods, which offer a less subjective approach, can provide additional information which it is not possible to obtain by manual analysis. An extensive literature review has been undertaken to investigate the background of automatic EEG analysis techniques. Frequency domain and time domain methods are considered and their limitations are summarised. The weakness in the R & K rules for visual classification and from which most of the automatic systems borrow heavily are discussed. A new technique - model based dynamic analysis - was developed in an attempt to classify the sleep EEG automatically. The technique comprises of two phases, these are the modelling of EEG signals and the analysis of the model's coefficients using dynamic systems theory. Three techniques of modelling EEG signals are compared: the implementation of the non-linear prediction technique of Schaffer and Tidd (1990) based on chaos theory; Kalman filters and a recursive version of a radial basis function for modelling and forecasting the EEG signals during sleep. The Kalman filter approach produced good results and this approach was used in an attempt to classify the EEG automatically. For classifying the model's (Kalman filter's) coefficients, a new technique was developed by a state-space approach. A 'state variable' was defined based on the state changes of the EEG and was shown to be correlated with the depth of sleep. Furthermore it is shown that this technique may be useful for automatic sleep staging. Possible applications include automatic staging of sleep, detection of micro-arousals, anaesthesia monitoring and monitoring the alertness of workers in sensitive or potentially dangerous environments.
21
Salem, Fatma Ezzahra. "Management of advanced sleep modes for energy-efficient 5G networks." Electronic Thesis or Diss., Institut polytechnique de Paris, 2019. http://www.theses.fr/2019IPPAS004.
Full textAbstract:
La consommation énergétique des réseaux radiomobiles a été une direction de recherche très active au cours de la dernière décennie et ce, pour des raisons économiques ainsi qu'environnementales. Avec l'énorme croissance du trafic ainsi que la multiplication des équipements mobiles, des nouveaux services et des communications Machine à Machine, la nécessité de réduire la consommation énergétique est devenue de plus en plus urgente surtout avec le déploiement des réseaux 5G. Sachant que le réseau d'accès est le plus grand consommateur dans le réseau mobile, en particulier les stations de base qui consomment environ 80% de la consommation totale, nous nous focalisons dans cette thèse sur ce composant. La consommation énergétique des stations de base est composée de deux parties: une partie fixe qui ne varie pas en fonction du trafic et une partie qui en dépend. Notre objectif est de trouver des solutions efficaces permettant de réduire la partie fixe de cette consommation. Une solution prometteuse consiste à mettre la station de base, ou certains de ses composants, en mode veille s'il n'y a pas de trafic à servir. Nous étudions dans cette thèse une technique dite "modes de veille avancés" qui permet d'éteindre les composants de la station de base de manière progressive en fonction du temps nécessaire pour chacun pour se désactiver et se réactiver de nouveau. Ceci introduit différent niveaux de sommeil possibles. En allant d'un niveau à un autre plus profond nous pouvons réaliser plus d'économies d'énergie puisqu'il y a plus de composants qui sont en veille, mais nous introduisons plus d'impact sur le délai s'il y a des demandes de services qui arrivent pendant cette période de veille. L'opérateur doit trouver alors des politiques de gestion efficaces pour gérer ce compromis entre la réduction d'énergie et la minimisation de l'impact sur le délai. Dans ce contexte, nous proposons des méthodes de gestion des modes de veille avancés basées spécifiquement sur des modèles d'apprentissage, à savoir les processus de décision Markoviens et le Q-learning, qui nous permettent de trouver la politique optimale à suivre en fonction des priorités accordées aux deux métriques : la consommation d'énergie et le délai. Nos solutions montrent que les économies d'énergie peuvent atteindre 90% dans le cas d'un faible trafic lorsque la priorité est accordée à la réduction d'énergie. Plus on augmente la contrainte imposée sur le délai, plus la réduction d'énergie diminue, et aussi l'impact sur le délai. Nos résultats montrent que même si la contrainte sur le délai est très forte, nous pouvons aussi avoir des économies d'énergie élevées (environ 50%) alors que l'impact sur le délai devient négligeableThe energy consumption of mobile networks has been an active research direction in the last decade for both environmental and economic concerns. With the tremendous growth in the traffic as well as the proliferation of devices and new services and the expansion of Machine to Machine communications, the need to reduce the energy consumption became more and more urgent and was emphasized by the expected 5G roll out. Knowing that the radio access network is the most energy consumer in the network, particularly the base station which consumes around 80% of the global energy consumption, we direct our study towards this component. The energy consumption of the base stations is composed of two parts: a fixed one that does not vary with the load, and a second part which is load-dependent. Our target is to find efficient solutions enabling to reduce the fixed component. One promising solution is to put the base station, or some of its components, into sleep mode whenever there is no traffic to serve. We study in this thesis an Advanced Sleep Mode technique enabling to shut down the base station's components in a gradual manner depending on the time needed for each of them to deactivate and reactivate again. This introduces different possible levels of sleep. Going from one level to a deeper one will help us make more energy savings as we deactivate more components but can also incur a larger delay for the users who request a service when the base station is in sleep mode. The network operator has to find efficient management solutions that can handle this tradeoff between energy consumption reduction that can be achieved by the sleep modes, and the minimization of the corresponding induced delay. To this aim, we propose in this work management solutions based especially on learning techniques, namely Markov Decision Processes and Q-learning, which enable us to find the optimal policy to follow depending on the priorities given to both metrics: energy consumption and delay. Our solutions show that the energy savings can reach 90% in low traffic when priority is given to energy reduction. The more we care about delay, the more energy saving decreases, as is the case for the induced delay. We show that even when we have a strict constraint on the delay, we can still achieve high energy savings (around 50%) while the added delay by the sleep mode is negligible
22
Jain, Sulabh. "Event-Driven Dynamic Query Model for Sleep Study Outcomes Research." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1323377417.
Full text
23
Joshi, Badal S. "A Doubly Stochastic Poisson Process Model for Wake-Sleep Cycling." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1247717872.
Full text
24
Swang, Theodore W. II. "A Mathematical Model for the Energy Allocation Function of Sleep." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483392711778623.
Full text
25
Tran, Martina. "Energy Consumption Optimizations for 5G networks." Thesis, Uppsala universitet, Signaler och System, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-395146.
Full textAbstract:
The importance of energy efficiency has grown alongside awareness of climate change due to the rapid increase of greenhouse gases. With the increasing trend regarding mobile subscribers, it is necessary to prevent an expansion of energy consumption via mobile networks. In this thesis, the energy optimization of the new radio access technology called 5G NR utilizing different sleep states to put base stations to sleep when they are not transmitting data is discussed. Energy savings and file latency with heterogeneous and super dense urban scenarios was evaluated through simulations with different network deployments. An updated power model has been proposed and the sensitivity of the new power model was analyzed by adjusting wake-up time and sleep factors. This showed that careful implementation is necessary when adjusting these parameter settings, although in most cases it did not change the end results by much. Since 5G NR has more potential in energy optimization compared to the previous generation mobile network 4G LTE, up to 4 sleep states was implemented on the NR base stations and one idle mode on LTE base stations. To mitigate unnecessary sleep, deactivation timers are used which decides when to put base stations to sleep. Without deactivation timers, the delay could increase significantly, while with deactivation timers the delay increase would only be a few percent. Up to 42.5% energy could be saved with LTE-NR non-standalone deployment and 72.7% energy with NR standalone deployment compared to LTE standalone deployment, while minimally impacting the delay on file by 1%.
26
Soehnlen, Steve G. "A Rat Model of Sleep Deprivation Prior to Traumatic Brain Injury." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1304627398.
Full text
27
Ahmed, Maha Shihab. "Improving energy efficiency and quality of service in an integrated wireless-optical broadband access network." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2015. https://ro.ecu.edu.au/theses/1737.
Full textAbstract:
Exponential growth in the volume of wireless data, boosted by the growing popularity of mobile devices such as smart phones and tablets, is forcing telecommunication industries to rethink network design, and focus on developing high capacity mobile broadband networks. Accordingly, researchers have undertaken developmental work for an integrated wireless-optical broadband access network (WOBAN). Passive optical networks (PONs) and fourth generation (4G) wireless networks are two major candidate technologies for the WOBAN. PON is a wired access technology, well-known for its high capacity, whereas 4G is a wireless broadband access technology, popular for its ease of deployment and ability to offer mobility. Integration of PON and 4G technologies, as a wireless-optical broadband access network, offers advantages such as extension of networks in rural areas, support for mobile broadband services, and rapid deployment of broadband networks. However, these two technologies have different design architectures for handling broadband services which require Quality of Service (QoS), for example, 4G networks use traffic classification for supporting different QoS demands whereas PON does not differentiate between traffic types. This integrated network must also be energy efficient, as a green broadband access network, without hindering QoS. While these technologies both use sleep mode, they differ in their power saving mechanisms.
This thesis first addresses a QoS solution for the incompatibility between these technologies. Service class mapping is proposed in Chapter 3 for the integrated WOBAN, based on the M/G/1 queuing model supported by an innovative priority scheduler. Once class mapping is deployed, a power saving mechanism can be devised by exploiting traffic differentiation. Specifically, a class-based strategy is proposed which helps optimise the sleep period for the terminal units of the optical network, without compromising QoS.
Since the optical network involves control and terminal nodes, both of which consume power, this thesis proposes an energy efficient mechanism that involves both components. In contrast, other published strategies (Chapter 2) have only considered the terminal units. Chapter 4 presents the mechanism for enabling global sleep (control and terminal nodes) and local sleep (terminal nodes), based on the available traffic's class structure. This mechanism enables sleep for different components within the bandwidth allocation by adapting the switching between predefined polling cycle lengths.
As the WOBAN is comprised of both wireless and optical parts, a dynamic resource management mechanism is needed which responds to changing daily traffic patterns across a green integrated network. Consequently, Chapter 5 proposes a mechanism which dynamically adapts the polling cycles, of the optical and wireless parts of the network, to the changing traffic volume and class composition. Tailored sleep durations for the components of the WOBAN are facilitated within the resource management regime, as these components differ in their ability to function efficiently if management of the sleep periods is not responsive to the changing traffic volumes and class composition.
This dissertation creates new knowledge by seamlessly integrating the two parts of WOBAN and introducing differentiated, class-based sleep for the components of the hybrid network to help realise a green WOBAN.
28
Bartolucci, Maria Lavinia <1985>. "Obstructive sleep apneas naturally occur in mice during REM sleep and are more prevalent in a mouse model of Down syndrome." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9675/1/Tesi_finale.pdf.
Full textAbstract:
Study Objectives. The use of mouse models in sleep apnea research is limited by the belief that central (CSA) but not obstructive sleep apneas (OSA) occur in rodents. With this study we wanted to develop a protocol to look for the presence of OSAs in wild-type mice and, then, to apply it to a mouse model of Down Syndrome (DS), a human pathology characterized by a high incidence of OSAs.
Methods. Nine C57Bl/6J wild-type mice were implanted with electrodes for electroencephalography (EEG), neck electromyography (nEMG), diaphragmatic activity (DIA) and then placed in a whole-body-plethysmographic (WBP) chamber for 8h during the resting (light) phase to simultaneously record sleep and breathing activity. The concomitant analysis of WBP and DIA signals allowed the discrimination between CSA and OSA. The same protocol was then applied to 12 Ts65Dn mice (a validated model of DS) and 14 euploid controls.
Results. OSAs represented about half of the apneic events recorded during rapid-eye-movement sleep (REMS) in each experimental group while almost only CSAs were found during non-REMS. Ts65Dn mice had similar rate of apneic events than euploid controls but a significantly higher occurrence of OSAs during REMS.
Conclusions. We demonstrated for the first time that mice physiologically exhibit both CSAs and OSAs and that the latter are more prevalent in the Ts65Dn mouse model of DS. These findings indicate that mice can be used as a valid tool to accelerate the comprehension of the pathophysiology of all kind of sleep apnea and for the development of new therapeutical approaches to contrast these respiratory disorders.
29
Yaghouby, Farid. "EXPERIMENTAL-COMPUTATIONAL ANALYSIS OF VIGILANCE DYNAMICS FOR APPLICATIONS IN SLEEP AND EPILEPSY." UKnowledge, 2015. http://uknowledge.uky.edu/cbme_etds/32.
Full textAbstract:
Epilepsy is a neurological disorder characterized by recurrent seizures. Sleep problems can cooccur with epilepsy, and adversely affect seizure diagnosis and treatment. In fact, the relationship between sleep and seizures in individuals with epilepsy is a complex one. Seizures disturb sleep and sleep deprivation aggravates seizures. Antiepileptic drugs may also impair sleep quality at the cost of controlling seizures. In general, particular vigilance states may inhibit or facilitate seizure generation, and changes in vigilance state can affect the predictability of seizures. A clear understanding of sleep-seizure interactions will therefore benefit epilepsy care providers and improve quality of life in patients. Notable progress in neuroscience research—and particularly sleep and epilepsy—has been achieved through experimentation on animals. Experimental models of epilepsy provide us with the opportunity to explore or even manipulate the sleep-seizure relationship in order to decipher different aspects of their interactions. Important in this process is the development of techniques for modeling and tracking sleep dynamics using electrophysiological measurements. In this dissertation experimental and computational approaches are proposed for modeling vigilance dynamics and their utility demonstrated in nonepileptic control mice. The general framework of hidden Markov models is used to automatically model and track sleep state and dynamics from electrophysiological as well as novel motion measurements. In addition, a closed-loop sensory stimulation technique is proposed that, in conjunction with this model, provides the means to concurrently track and modulate 3 vigilance dynamics in animals. The feasibility of the proposed techniques for modeling and altering sleep are demonstrated for experimental applications related to epilepsy. Finally, preliminary data from a mouse model of temporal lobe epilepsy are employed to suggest applications of these techniques and directions for future research. The methodologies developed here have clear implications the design of intelligent neuromodulation strategies for clinical epilepsy therapy.
30
D'Agnese, Mattiangelo. "Sleep-wake cycle: a new analysis for the two-step process model." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19307/.
Full textAbstract:
Il ciclo sonno-veglia é oggetto di studio per molti scienziati e matematici da più di trent’anni ma nonostante ciò molti quesiti non trovano ancora una risposta. Capire i meccanismi e le dinamiche del ciclo sonno-veglia è un problema molto importante perché le sue alterazioni possono avere conseguenze significative sulla salute umana.
In questo lavoro viene presentato un modello matematico, con basi biologiche, del ciclo sonno-veglia. La principale novità rispetto ai modelli precedenti è l’utilizzo di un accurato modello neuronale, il modello di Hodgkin-Huxley, che permette di descrivere il sistema usando connessioni sinaptiche realistiche.
Crediamo fermamente che questo argomento meriti una investigazione dettagliata, non solo per il contenuto fisico e matematico, ma anche per il suo potenziale impatto sulla ricerca nel campo della sanità.
31
Fallon, Joanne. "GROWING UP IN IRELAND: FACTORS IMPACTING SLEEP PATTERNS OF PRETERM INFANTS." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3736.
Full textAbstract:
GROWING UP IN IRELAND: FACTORS IMPACTING SLEEP PATTERNS OF PRETERM INFANTS
By Joanne Fallon MS, OT, PhD
A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University
Virginia Commonwealth University, 2015.
Major Director: Shelly J. Lane, PhD, Professor, Department of Occupational Therapy
Preterm infants represent the largest child patient group in the European Union (EU), accounting for 5.5-11.4% of all births (European Foundation for the Care of Newborn Infants, 2011b). Preterm birth is defined as birth prior to 37 weeks gestation. Infants born late preterm (34-36 weeks) are considered more similar to early preterm (> 34 weeks) than to full-term infants, despite previously regarded as near-term (Raju Higgins, Stark, & Leveno, 2006). For preterm infants, sleeping functions are critical as they demonstrate the ability to adjust to biological and social rhythms and support emotional regulation, learning, and memory. Many studies have focused on sleep patterns of full-term infants; however, few have investigated preterm infants and none have compared early and late preterm infants with a population from the Republic of Ireland. The purpose of this study was to identify infant and parent characteristics that promote optimal sleep in preterm infants and to establish whether the parent-infant relationship mediates this association. A secondary purpose was to test the transactional model of sleep. Parent report of infant sleep
was taken from a recent population-based dataset from the Republic of Ireland. A comparison of the day and nighttime sleep patterns of early and late preterm infants found no difference between groups. There was also no difference in infant temperament, breast-feeding, parental stress, depression, or sociodemographics. A difference was found between groups in infant development, weight at 9 months, and age infant began solid foods. This finding was not surprising as infants born early preterm are at greater at greater risk of developmental delay and disability. Results of this study suggest that the paternal-infant relationship has a mediating impact on the relationship between infant temperament and nighttime waking in the early preterm group only, while the maternal-infant relationship has a mediating role in both groups. These findings add to the body of knowledge on the transactional model of sleep, and are the first to identify infant temperament and the paternal-infant relationship as important factors. Implications of these results are discussed in the context of the transactional model of sleep and recommendations for future research are presented.
32
Kazerani, Ali. "Development and analysis of a simple grey-box model of central sleep apnea." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82405.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 125-126).
In this thesis, we develop and analyze a simple grey-box model that describes the pathophysiology of central sleep apnea (CSA). We construct our model following a thorough survey of published approaches. Special attention is given to PNEUMA, a complex, comprehensive model of human respiratory and cardiovascular physiology that brings together many existing physiological models. We perform a sensitivity analysis, concluding that signals of interest in PNEUMA are insensitive to changes in all but approximately twenty parameters. This justifies our goal of developing a small, simple model that captures approximately the same behaviour among signals of interest. The simplicity of our model not only makes it accessible to analytical and intuitive exploration, but also opens up the possibility that its parameters could be reliably estimated from a patient's data records. This could be of great value in developing patient-specific or state-specific treatments for CSA. Our model describes the dynamics of the alveolar gas exchange, blood gas transport, and cerebral gas exchange processes, which together determine the cerebral and arterial partial pressures of carbon dioxide, given ventilation as input. Our model of the ventilatory controller senses both the cerebral and arterial carbon dioxide partial pressures and issues a ventilatory drive command from which the level of ventilation is determined, closing the loop. We develop a linearized small-signal model of our system and determine conditions for its stability. We conclude by comparing the stability predictions suggested by our linear analysis to the stability properties of our original nonlinear model, with promising results.
by Ali Kazerani.
S.M.
33
Turnbull, Christopher David. "CPAP withdrawal as a model of the cardiovascular effects of obstructive sleep apnoea." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:015bc59d-568b-4d49-b51b-192f4800a84a.
Full textAbstract:
Obstructive sleep apnoea (OSA) is associated with cardiovascular disease and hypertension. The underlying causes of cardiovascular disease and hypertension in OSA are not fully understood. Potential causes for cardiovascular disease and hypertension in OSA include; intermittent hypoxia, arousal mediated sympathetic activation, oxidative stress, endothelial dysfunction, and systemic inflammation. Continuous positive airway pressure (CPAP) is the standard treatment for OSA and CPAP withdrawal is used to model the consequences of OSA. In the CPAP withdrawal model patients with known OSA are withdrawn from their usual CPAP treatment and randomised to intervention or control for two weeks. Utilising a CPAP withdrawal model, I examined the effects of supplemental oxygen versus air (sham) during CPAP withdrawal on several outcomes, including; morning blood pressure, intermittent hypoxia, markers of arousal, and daytime sleepiness. In addition, I examined the effects of the return of OSA following CPAP withdrawal on several biomarkers. Supplemental oxygen virtually abolished the rise in morning blood pressure seen following CPAP withdrawal. Supplemental oxygen markedly attenuated intermittent hypoxia, whilst having little effect on markers of arousal, and no effect on daytime sleepiness. This suggests that intermittent hypoxia is the dominant cause of morning increases in blood pressure in OSA. Following CPAP withdrawal there was a small unexpected reduction in adrenomedullin, which is a potent vasodilator and may contribute to the blood pressure rise with CPAP withdrawal.
34
Pritchett, David. "Sleep, circadian and behavioural characterisation of two schizophrenia-relevant transgenic mouse models." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:1853944f-8ee1-4ed8-9214-d8a61c6bb46d.
Full text
35
Brown, Stephanie A. T. "Maritime Platform Sleep and Performance Study: Evaluating the SAFTE Model for Maritime Workplace Application." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/7313.
Full textAbstract:
Approved for public release; distribution is unlimitedTechnological advances in ship systems have enhanced the capabilities of United States Naval vessels in recent years, however, these changes come with unintended consequences. Only in recent years have we begun to study the effects of motion on the work/rest patterns of human operators in environments. The purpose of this study was to research the performance issues related to motion in combination with the reduction of staffing onboard naval vessels. This study supports previous findings that increased motion at sea causes a decrease in sleep quality and increase in perceived fatigue. It also confirms that reaction time decreases under motion conditions. Additionally, this study addressed concerns about the analytical approach used to assess actigraphic data and self-reported work/rest patterns in operational environments. This thesis examined the Fatigue Avoidance Scheduling Tool interface, determining that its performance predictions are dependent upon the assumptions used to score and smooth the data prior to transfer into the interface. The actual performance compared to the FASTTM performance predictions that uses the Sleep, Activity, Fatigue, and Task Effectiveness mathematical model, indicated that the models reservoir depletion/replenishment rate did not adequately account for the effect of long-term fragmented sleep as seen in the operational maritime environment.
36
Kim, Jung Eun. "Analysis of Sleep-Wake Transition Dynamics by Stochastic Mean Field Model and Metastable State." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406206931.
Full text
37
Bizzotto, Roberto. "A Mixed-Effect Multinomial Markov-Chain Model for Describing Sleep Architecture in Insomniac Patients." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3425337.
Full textAbstract:
The decrease of sleep quality highly compromises the physical and mental well-being of the human body and is a common disorder affecting a large seg-ment of world’s population. The quality of nocturnal sleep is determined by its internal structure, i.e. the pattern through different physiological conditions of the body during the night. This structure, called ‘sleep architecture’, can be expressed by different stages (awake, stage 1 and 2 of light sleep, slow-wave sleep and REM sleep) and the transitions between them during nighttime, and can be modified through drugs for insomnia treatment. The sequence of sleep stages, objectively assessed every 30 seconds through polysomnography (PSG), constitute the so-called ‘PSG signal’ and can be seen as a finite succes-sion of categorical, nominal (i.e., non-ordered) data.
In the context of modeling of drug effects (pharmacodynamic, PD) and correlations between drug exposure (pharmacokinetics, PK) and drug effect, the analysis of categorical nominal polychotomous data has been explored on-ly recently. The interest on the subject has strongly grown, also because many other pharmacodynamic data provided by clinical studies during drug devel-opment share the same characteristics. PK-PD modelling of categorical data requires specific methodologies. When dealing with nominal polychotomous data, the most interesting approach is the use of mixed-effect non-homogeneous Markov-chain models, whose parameters are related to the evo-lution of the probabilities of transitioning between different states of the chain for increasing values of the independent variable. Despite their relevance, such models present many aspects which have only been partially investigated in the literature so far.
This thesis is dedicated to the introduction of multinomial logistic func-tions as link functions for describing transition probabilities in the Markov-chains with more than two states. Binary logistic functions have previously been used, instead. A new model for sleep architecture is therefore imple-mented and evaluated, using PSG placebo data obtained from a clinical study in patients affected by primary insomnia. Parameter estimation is accomplished through maximization of Laplace-approximated likelihood, using NONMEM VI. Model evaluation is performed through standard techniques, like inspection of goodness-of-fit plots, bootstrap and simplified posterior predictive check.
Later on in the thesis, the new multinomial Markov-chain model is further developed by combining the strengths of other existing models, and by adding additional components. The major investigated features are the predictors of the multinomial logits, the model parameterization, the relevance of the vari-ous stages and transitions, and the description of the inter-individual variabili-ty.
The final model is internally evaluated through simplified posterior pre-dictive check and two other diagnostics based on Monte Carlo simulation: vis-ual predictive check, implemented not only on stage frequencies (as done in the literature) but also on transition frequencies along the night; and visual estimation check, introduced here for the first time in the context of PK-PD mixed-effect modeling. This tool aims to evaluating the capability of accurately and precisely estimating model parameters through a graphic description of accuracy and precision on the estimation of transition probabilities time-course. The three diagnostics show an overall good performance of the devel-oped multinomial Markov-chain model in describing and reproducing the data, and of the employed estimation technique in producing robust estimates of the model parameters.
The final model is also externally evaluated, using data from a new clinical study in patients with the same conditions as the original study. The evaluation is mainly performed looking at minimized objective function values and at new simplified posterior predictive checks. The new proposed model is shown to adequately describe also the new data.
In the last part of the thesis, stepwise covariate modeling is adopted for investigating the appropriate structural form of a second stage model in which age, body mass index and gender effects are integrated in the base model. The statistical relevance of these covariate effects is computed on the original in-somniac population, together with the entity of the effects themselves. Inter-esting and novel results are shown, depicting how each of the three covariates affects some of the transition probabilities of the multinomial Markov-chain model, during specific nighttime intervals.La riduzione della qualità del sonno compromette considerevolmente il benessere psico-fisico del corpo umano ed è un disturbo comune ad un’ampia fetta della popolazione mondiale. La qualità del sonno notturno è determinata dalla sua struttura interna, ossia il percorso attraverso diverse condizioni fisiologiche dell’individuo nella notte. Tale struttura, chiamata ‘architettura del sonno’, può essere espressa attraverso diversi stadi (veglia, stadi 1 e 2 del sonno leggero, sonno profondo e sonno REM) e le transizioni tra di essi durante la notte, e può essere modificata da farmaci preposti al trattamento dell’insonnia. La sequenza di stadi del sonno, oggettivamente determinabili ogni 30 secondi attraverso polisonnografia, costituisce il cosiddetto ‘segnale PSG’ e può essere vista come una successione finita di dati categoriali nominali (cioè, non ordinati). Nel contesto della modellistica degli effetti farmacologici (farmacodinamica, PD) e delle correlazioni tra esposizione al farmaco (farmacocinetica, PK) ed effetti farmacologici, l’analisi di dati categoriali nominali policotomi è stata esplorata solo recentemente. L’interesse su di essa è cresciuto fortemente, anche perchè molti altri dati farmacodinamici provenienti da studi clinici fatti per sviluppare nuovi farmaci condividono le stesse caratteristiche. La modellistica PK-PD di dati categoriali richiede metodologie specifiche. Quando i dati sono nominali policotomi, l’approccio più interessante è l’utilizzo di modelli ad effetti misti a catena di Markov non omogenea, i cui parametri sono legati all’evolversi delle probabilità di transizione tra i diversi stati della catena al variare della variabile indipendente. Questi modelli però hanno presentato fin’ora molti aspetti specifici che in letteratura sono stati sviscerati solo parzialmente. Questa tesi è dedicata all’introduzione delle funzioni logistiche multinomiali come funzioni link in grado di descrivere le probabilità di transizione nelle catene di Markov con più di due stati. Precedentemente invece, erano state utilizzate funzioni logistiche binarie. Nella tesi viene quindi implementato e validato un nuovo modello dell’architettura del sonno, facendo uso di dati PSG ottenuti da uno studio clinico in soggetti con diagnosi di insonnia primaria, ai quali era stato somministrato placebo. La stima parametrica viene effettuata tramite massimizzazione della verosomiglianza approssimata con metodo di Laplace, utilizzando NONMEM VI. La validazione del modello avviene tramite tecniche consolidate, come l’ispezione dei goodness-of-fit plot, il bootstrap ed il simplified posterior predicitve check. Nel prosieguo della tesi il nuovo modello multinomiale a catena di Markov viene ulteriormente sviluppato fondendo i punti di forza di altri modelli esistenti nell’ambito considerato, ed aggiungendo nuovi elementi. I predittori delle funzioni logit multinomiali, la parametrizzazione del modello, la rilevanza di transizioni e stadi diversi, la descrizione della variabilità interindividuale sono i principali ambiti di analisi. Il modello finale viene validato internamente attraverso simplified posterior predictive check e due altri metodi diagnostici basati su simulazione Monte Carlo: il visual predictive check, implementato non solo sulle frequenze degli stadi (come fatto in letteratura), ma anche sulle frequenze delle transizioni nel corso della notte; ed il visual estimation check, introdotto qui per la prima volta nel contesto della modellistica PK-PD ad effetti misti. Questo strumento ha l’obiettivo di validare la capacità di stimare i parametri del modello in modo preciso ed accurato attraverso una descrizione grafica dell’accuratezza e della precisione nella stima delle probabilità di transizione nel corso della notte. I tre strumenti diagnostici mostrano una buona performance nel descrivere e riprodurre i dati, per quanto riguarda il modello multinomiale a catena di Markov sviluppato, e nel produrre stime robuste dei parametri del modello, per quanto concerne il metodo di stima adottato. Il modello finale viene validato anche esternamente, con dati ottenuti da un nuovo studio clinico in pazienti con condizioni uguali a quelle dei pazienti dello studio originale. La validazione viene effettuata valutando principalmente i valori minimizzati della funzione obiettivo ed i nuovi simplified posterior predictive check. I suoi risultati mostrano che il nuovo modello proposto è in grado di descrivere adeguatamente anche i nuovi dati. Nell’ultima parte della tesi, il processo di stepwise covariate modeling viene usato allo scopo di scegliere la forma strutturale appropriata di un modello del secondo stadio in cui gli effetti di età, indice di massa corporea e sesso vengono integrati nel modello base. La significatività statistica di tali effetti viene quindi calcolata sulla popolazione originaria di soggetti insonni, insieme all’entità degli effetti stessi. Gli innovativi ed interessanti risultati di questa analisi mostrano come ciascuna covariata influenza alcune probabilità di transizione del modello multinomiale a catena di Markov, durante specifici intervalli della notte.
38
Domarski, Shannon. "Neurological disorders: A model for parsimony." Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/752.
Full textAbstract:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucfBachelors
Arts and Sciences
Psychology
39
Biard, Kathleen. "Effects of Pharmacological Manipulation of the Serotonergic/Cholinergic Systems on Sleep Structure in Two 5-HT1A Genotypes: Implications for a Model of Depression." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33005.
Full textAbstract:
The serotonergic and cholinergic systems are jointly involved in regulating sleep but this balance is theorized to be disturbed in depressed individuals (Janowsky 1972, Jouvet 1972). One potential cause of disturbed neurotransmission is genetic predisposition. The G(-1019) allele of the 5-HT1A receptor predicts an increased risk for depression compared to the wild-type C(-1019) allele.
The goal of this study was to use pharmacological probes in normal controls to model the serotonergic/cholinergic imbalance of depression and its associated abnormalities in sleep structure while controlling for 5-HT1A receptor genotype.
Seventeen healthy female participants homozygous for either C (n=11) or G (n=6) alleles, age 18-27 years were tested on four non-consecutive nights. Participants were given galantamine (an anti-acetylcholinesterase), buspirone (a serotonergic agonist), both drugs together, or placebos before sleeping.
Buspirone suppressed tonic REM: there was a significant increase in REM latency (p<0.001). Galantamine increased tonic REM sleep, leading to more time spent in stage REM (p<0.001) and shorter REM latency (p<0.01). Galantamine and buspirone given together tended to negate the effects of each other on REM sleep measures but disrupted sleep more than either drug alone, showing lower SE and N3% and increased awakenings, Wake% and N1% (p<0.019). There was no main effect of genotype nor was there a significant multivariate interaction between genotype and drug condition.
These findings are partially consistent with the literature about sleep in depression, notably short REM latency, higher percentage of total sleep time spent in REM, and increased sleep fragmentation. The C/G mutation in the 5-HT1A receptor does not appear to cause noticeable differences in the sleep patterns of healthy young females.
40
Becker, Nico [Verfasser]. "Non-stationary service curves : model and estimation method with application to cellular sleep scheduling / Nico Becker." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2021. http://d-nb.info/1230550941/34.
Full text
41
Bencs, Nicole. "Developing Educational Material To Promote Awareness Of Nicotine Use As A Significant Risk Factor For Sudden Infant Death Syndrome." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/338754.
Full textAbstract:
Introduction and Rationale: Sudden infant death syndrome (SIDS) continues to be the leading cause of death in infants 28 days to 12 months old and the third leading cause of infant mortality (CDC, 2014; Task Force on SIDS, 2011a). SIDS has no identifiable cause although many hypotheses have existed and there are many known risk factors. Nicotine use is the second most modifiable risk factor for SIDS and to date there is no national public education campaign. Formal education is needed. Written education materials, such as brochures, are an effective way to increase knowledge and awareness of a health topic. Purpose and Objective: The purpose of this DNP Project was to create an educational brochure about SIDS and nicotine as a significant modifiable risk factor. The brochure is directed towards pregnant women and women with infants less than 12 months of age. The objective was to educate and inform mothers about SIDS, nicotine and its relation to SIDS, and the importance of abstaining from nicotine during and after pregnancy. Methods: The brochure was created using the Health Belief Model (HBM) as a framework. The HBM was used to explain health behavior modifications and was used as a foundation for education interventions. The model has successfully been applied to explain other preventative health behaviors and provide health education in various contexts. Results: The brochure was evaluated by two subject matter experts who have published peer reviewed articles using the HBM. Both subject matter experts found the HBM applied to the brochure appropriately. In their opinion, the content of the brochure should have positive impact for health modification in women who use nicotine and are pregnant or have a child less than 12 months of age. Conclusions: This DNP Project demonstrated SIDS as a current significant health problem and identified maternal nicotine use as the second most modifiable risk factor. Due to lack of current public education, a brochure was created using the HBM as a framework. Subject matter experts stated the brochure was created based on the HBM and will likely a have positive health influence on the intended population.
42
Yoo, Paul B. "SELECTIVE STIMULATION AND RECORDING OF THE CANINE HYPOGLOSSAL NERVE FOR THE TREATMENT OF OBSTRUCTIVE SLEEP APNEA." Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1081536516.
Full text
43
Hrabetova, Sabina, Ang Sherpa, and Fanrong Xiao. "Diffusive spread of substance through brain extracellular space in in vitro model of sleep and awake brain states." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-198264.
Full text
44
Tian, Nan. "SLEEP-RELATED GENERALIZED TONIC SEIZURE AND HIGH FREQUENCY OSCILLATION (HFOs) IN A MESIAL TEMPORAL LOBE EPILEPSY MOUSE MODEL." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1277440218.
Full text
45
Pelteret, Jean-Paul. "A computational neuromuscular model of the human upper airway with application to the study of obstructive sleep apnoea." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9519.
Full textAbstract:
Includes bibliographical references.Numerous challenges are faced in investigations aimed at developing a better understanding of the pathophysiology of obstructive sleep apnoea. The anatomy of the tongue and other upper airway tissues, and the ability to model their behaviour, is central to such investigations. In this thesis, details of the construction and development of a three-dimensional finite element model of soft tissues of the human upper airway, as well as a simplified fluid model of the airway, are provided. The anatomical data was obtained from the Visible Human Project, and its underlying micro-histological data describing tongue musculature were also extracted from the same source and incorporated into the model. An overview of the mathematical models used to describe tissue behaviour, both at a macro- and microscopic level, is given. Hyperelastic constitutive models were used to describe the material behaviour, and material incompressibility was accounted for. An active Hill three-element muscle model was used to represent the muscular tissue of the tongue. The neural stimulus for each muscle group to a priori unknown external forces was determined through the use of a genetic algorithm-based neural control model. The fundamental behaviour of the tongue under gravitational and breathing-induced loading is investigated. The response of the various muscles of the tongue to the complex loading developed during breathing is determined, with a particular focus being placed to that of the genioglossus. It is demonstrated that, when a time-dependent loading is applied to the tongue, the neural model is able to control the position of the tongue and produce a physiologically realistic response for the genioglossus. A comparison is then made to the response determined under quasi-static conditions using the pressure distribution extracted from computational fluid-dynamics results. An analytical model describing the time-dependent response of the components of the tongue musculature most active during oral breathing is developed and validated. It is then modified to simulate the activity of the tongue during sleep and under conditions relating to various possible neural and physiological pathologies. The retroglossal movement of the tongue resulting from the pathologies is quantified and their role in the potential to induce airway collapse is discussed.
46
Kim, Seung Jae. "Brain Mechanisms Regulating Sympathetic Vasomotor Function in a Rodent Model of Sleep Apnoea: Neurotransmitters, Networks, and the Circulation." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20147.
Full textAbstract:
Central motor command from the sympathetic networks of the brain and the spinal cord are crucial for maintaining normal cardiovascular function. Understanding the mechanisms that increase sympathetic tone and reflex function are important to prevent neurogenically-mediated hypertension. Chapter 4 investigates the contribution of a hypothalamic neurotransmitter, orexin-A, in causing sympathoexcitation following intermittent hypoxia. Spinal orexin receptor signalling does not contribute to the elevation in sympathetic drive that is observable following intermittent hypoxia but contributes to enhanced chemoreflex sensitivity. Chapter 5 examines the relevance of angiotensin II in eliciting changes in sympathetic activity following intermittent hypoxia. The activation of angiotensin receptors at the level of the subfornical organ and carotid bodies is critical to sympathoexcitation induced by repeated hypoxia. Furthermore, central cardiorespiratory coupling and sensitisation of chemoreflex function are angiotensin II-mediated, and responses that are specific to the carotid bodies. Chapter 6 expands on the previous chapter, demonstrating that the activation of subfornical organ neurons by hypoxia requires central angiotensin receptor signalling. Hypoxia reduces renal blood flow, while simultaneously activating neurons in the subfornical organs. Activation of subfornical organ neurons, at least in some subpopulations, rely on angiotensin type 1 receptor activation. Together, this thesis reports 1) the hypothalamic orexin network contributes to reflex mechanisms of sympathetic regulation, at least during episodic reductions in blood oxygen levels, and 2) angiotensin II is critical for triggering mechanisms that produce sympathoexcitation following intermittent hypoxia, an effect relayed via activation of the subfornical organ and possibly by AT1R-mediated activation of the carotid bodies.
47
Robinson, Melissa J. "Learning Healthy Sleep Behaviors: The Importance of Selection, Self-Concepts, and Social Comparison in Narrative Self-Education." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492435342459696.
Full text
48
Seicean, Sinziana. "Exploring Sleep and the Hispanic Paradox in Mexico-born U.S. Adult Immigrants." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1278623005.
Full text
49
Ha, Rick Wan Kei. "A Sleep-Scheduling-Based Cross-Layer Design Approach for Application-Specific Wireless Sensor Networks." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/918.
Full textAbstract:
The pervasiveness and operational autonomy of mesh-based wireless sensor networks (WSNs) make them an ideal candidate in offering sustained monitoring functions at reasonable cost over a wide area. To extend the functional lifetime of battery-operated sensor nodes, stringent sleep scheduling strategies with communication duty cycles running at sub-1% range are expected to be adopted. Although ultra-low communication duty cycles can cast a detrimental impact on sensing coverage and network connectivity, its effects can be mitigated with adaptive sleep scheduling, node deployment redundancy and multipath routing within the mesh WSN topology. This work proposes a cross-layer organizational approach based on sleep scheduling, called Sense-Sleep Trees (SS-Trees), that aims to harmonize the various engineering issues and provides a method to extend monitoring capabilities and operational lifetime of mesh-based WSNs engaged in wide-area surveillance applications. Various practical considerations such as sensing coverage requirements, duty cycling, transmission range assignment, data messaging, and protocol signalling are incorporated to demonstrate and evaluate the feasibility of the proposed design approach.
50
Hrabetova, Sabina, Ang Sherpa, and Fanrong Xiao. "Diffusive spread of substance through brain extracellular space in in vitro model of sleep and awake brain states: Diffusive spread of substance through brain extracellular space in in vitromodel of sleep and awake brain states." Diffusion fundamentals 24 (2015) 23, S. 1, 2015. https://ul.qucosa.de/id/qucosa%3A14539.
Full text