• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 680
  • 143
  • 109
  • 36
  • 34
  • 26
  • 16
  • 10
  • 9
  • 8
  • 7
  • 6
  • 5
  • 5
  • 2
  • Tagged with
  • 1204
  • 1204
  • 375
  • 279
  • 278
  • 257
  • 245
  • 218
  • 207
  • 164
  • 160
  • 139
  • 138
  • 126
  • 122
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

DMX-communication over Bluetooth low energy mesh network

Danielsson, Thomas January 2019 (has links)
With the addition of mesh capability to Bluetooth low energy(BLE) in 2017 new possibilities open up for the Internet of Things applications of Bluetooth. With the rapidly increasing number of connected devices a few new standards are competing for being the standard protocol for low power mesh communication. BLE is mostly aimed towards low bandwidth data such as sensor readings or light control. However, this thesis attempts to investigate the viability of adapting BLE mesh nodes to communicate DMX-data which is a protocol widely used in lightning and stage effects. The system is implemented on Bluetooth development kits and the latency and power consumption are measured. The results show that the latency is significant and with high variance if the full DMX frame is transmitted, rendering the application non-applicable on many real-time applications. It can however be justified in some applications due to Bluetooth's well established eco-system of devices and functionality where the nodes could extend their capabilities by implementing already established BLE models. By only transmitting the updated channels the latency can be lowered to values that would in some applications be indistinguishable from wired connection. The energy consumption of BLE mesh suffers greatly with the addition of mesh due to its constant scanning but by implementing low power nodes which keep the radio off during certain intervals this consumption could be greatly decreased. The results also show a high variance of latency depending on the node configuration regarding to the placements and the number of hops required to reach the intended recipient. / Bluetooth har länge varit standardprotokollet för kommunikation mellan två stycken enheter. 2017 kom tillägget med mesh till Bluetooth. Mesh innebär att andra enheten i närheten ska skicka vidare meddelanden och därigenom tillåta kommunikation mellan enheter som är utanför direkt radiokontakt. DMX är ett protokoll som används inom ljus- och sceneffekter. Bluetooth mesh är utformat för att skicka små datamängder som till exempel sensordata eller styra glödlampor. Denna uppsats kommer utvärdera om det är användbart att skicka DMX-data över Bluetooth mesh. En implementation gjordes på Bluetooth utvecklingskort och resultatet visar på en signifikant fördröjning och med hög varians vid överföring av alla DMX-kanaler, vilket innebär att denna implementation inte är användbar vid många användningsområden. Men trots det kan den vid vissa fall vara användningsbar, mycket till hjälp av Bluetooths billiga och utbyggda ekosystem av produkter och tilläggsfunktioner. Eftersom Bluetooth mesh byggs in i en del befintliga byggnader kan de uppoffringar man får göra vid överföringar av DMX-data vara acceptabel då man kan uttnyttja befintliga nät. Strömförbrukningen ökar avsevärt vid mesh jämfört med klassisk lågenergi Bluetooth då mesh måste skanna radiotrafiken konstant. Vid implementationen av lågenergi noder kan dock radio vara i stand-by och starta endast vid speciella tidpunkter och man kan därigenom få avsevärt lägre strömförbrukning, med uppoffringen att DMX-datan inte kan överföras omgående. Det visade sig också att noduppställningen kraftigt påverkade variansen i överföringshastighet och att detta måste ta i hänsyn vid valet om DMX över Bluetooth mesh är användbart i just det fallet.
72

Monitoring Air Quality in Ångström Cleanroom Laboratory

Kanestad, Linus, Andersson, Gustaf, Hällgren, Karl-Johan January 2019 (has links)
The air quality in the Ångström cleanroom was to be measured for monitoring and control purposes, with the measurements displayed on a website. To do this several sensors, micro controllers, means of communication, and ways to host the server were investigated. In the end the chosen components were the DHT12 sensor, Arduino Nano micro controllers, 433MHz LoRa modules for communication, and a Raspberry Pi for data aggregation and website hosting. Four edge nodes with sensors were placed in locations of interest and transmitted data to the central node that hosted the website. For the website a development methodology called AJAX was used to handle data, and the HTML canvas element was used to display data. The system as a whole met its requirements.
73

Saving resources through smart farming : An IoT experiment study

Jonarv Hultgren, Susanne, Tennevall, Philip January 2019 (has links)
Context: Smart farming, agritech, is growing in popularity and is starting to develop rapidly with some already existing technology that is implemented in agriculture for both industrial and private use. Objectives: The goal of this thesis is to investigate the benefits and issues with implementing technology in agriculture, agritech. In this thesis the investigation and research is performed by conduction a literature study and an experiment. Realization: A prototype was created to monitor the soil moisture level and calculating the average soil moisture value, then water the plants when needed. This was then compared to a manually watered pot to investigate if agritech could reduce the water usage when maintaining plants. Results: The result of the experiment indicates that it is possible to improve the use of resources such as human labor, time spent on maintaining the plants and water usage. Conclusions: The conclusion of this thesis is with the help of agritech, human workers can spend more time on other tasks and maintain the technology implemented. Instead of observing the plants to see if they need watering and watering them manually. Water usage may also be minimized with the help of sensors that make sure the plants only get watered when needed by constantly checking the soil moisture level.
74

Data stream mining in fog computing environment with feature selection using ensemble of swarm search algorithms

Ma, Bin Bin January 2018 (has links)
University of Macau / Faculty of Science and Technology. / Department of Computer and Information Science
75

Receive and Transmit Spatial Modulation Techniques for Low Complexity Devices / Techniques de modulation spatiales à l'émission et à la réception pour les objets à bas complexité

Mokh, Ali 15 November 2018 (has links)
L'Internet des objets est l'un des concepts clefs stimulant l'évolution des réseaux mobiles dans le but de leur donner de nouvelles fonctionnalités de communication et de gestion d'objets dits connectés. Comparativement aux terminaux mobiles standards, les usages associés à ces objets connectés sont en général caractérisés par des débits modestes et de faibles ressources en capacité de calcul et en énergie. Les techniques de modulation spatiale (SM) sont proposées comme une solution prometteuse pour assurer les débits des objets connectés tout en maîtrisant le critère de la consommation énergétique. L'objectif de cette thèse est d'étudier les performances de différents schémas de transmission basés sur le concept SM mis en oeuvre en transmission ou en réception. Nous avons notamment proposé un système global de communication en liaisons montante (SM en transmission) et descendante (SM en réception) entre une station de base et un objet, dans lequel l'essentiel de la complexité de calcul est concentré à la station de base. Par ce système, une liaison avec un objet peut être établie en limitant les traitements au sein de l'objet à di simples fonctions d'activation/désactivation d'antenne et de détection à seuil. Par ailleurs, nous avons proposé des schémas SM étendus grâce auxquels l'efficacité spectrale atteignable devient égale au nombre d'antennes au sein de l'objet. Les expressions analytiques de la probabilité d'erreur binaire ont été développées pour l'ensemble des systèmes étudiés en utilisant différentes méthodes de détection. L'impact de la connaissance imparfaite de l'état des canaux de propagation ainsi que l'effet des corrélations entre antennes ont également été incorporés dans l'étude des performances des schémas SM de réception. Dans une dernière partie, nous avons proposé d'adapter les schémas SM de réception dans un environnement de propagation en ondes millimétriques en utilisant une formation de faisceau hybride analogique/numérique au niveau de l'émetteur. / Internet of Things is one of the keyword that represents the evolution in 5G that is able to connect the so-called Connected Devices (CD) to the network. These CDs are expected to require modest data rates and will be characterized by low resources in terms of both computation and energy consumption compared to other mobile multi-media devices. Spatial Modulation (SM) is proposed to be a promising solution to boost the data rate of the CD with a small ( or no) increase in energy consumption. Inspired by the advantages of SM, the objective of this thesis is to study the performance of different transmission scheme based on the SM concept at the transmitter and at tht receiver, for respectively an uplink and a downlink transmission between a BS and a CD. We proposed a global system where the higher computational complexity remains at the BS: The transmit SM is used for uplink, and the receive SM for downlink. It is shown that with SM, an ON­OFF keying for uplink and Single Tap detector for downlink could be sufficient for the transmission a the CD. Also, with Extended SM schemes, we increased the spectral efficiency of SM to be equal t< the number of antennas of CD in both uplink and downlink transmission. A framework for the derivation of the Bit Error Probability (BEP) is developed for all schemes with different detection methods. Impact of imperfect CSIT transmission has been studied when linear precoding is implemented for the receive spatial modulation, as well as the effect of antenna correlations. Finally we proposed to adapte the spatial modulation at the receiver with the mmWave environment, using hybrid beamformina at the transmitter.
76

Internet of Things mesh network : Using the Thread networking protocol

Alm, Anton January 2019 (has links)
This thesis summarizes my project in setting up a Thread network. The idea of this project was presented by the company ÅF in Karlstad, Sweden. ÅF wishes to upgrade their current demonstrator for IoT. The current demonstrator includes Azure Cloud component, Raspberry Pi, Bluetooth and Arduino components. The upgrade includes implementing Thread technology together with Thread verified hardware from Nordic semiconductor and the Raspberry Pi Foundation. Thread is an IoT mesh networking protocol that was released year 2014. Compared to Bluetooth it offers IP communication (including IPv6) combined with higher reliability, performance and security. The process of installing, compiling and configuring the Thread network is explained. The result is an operational thread network that has sensor devices sending data to an HTTP web server, where the data is stored and monitored. Though, there are many improvements and functions that can be implemented to make this demonstrator more appealing.
77

Cluster heads selection and cooperative nodes selection for cluster-based Internet of Things networks

Song, Liumeng January 2017 (has links)
Clustering and cooperative transmission are the key enablers in power-constrained Internet of Things (IoT) networks. The challenges for power-constrained devices in IoT networks are to reduce the energy consumption and to guarantee the Quality of Service (QoS) provision. In this thesis, optimal node selection algorithms based on clustering and cooperative communication are proposed for different network scenarios, in particular: • The QoS-aware energy efficient cluster heads (CHs) selection algorithm in one-hop capillary networks. This algorithm selects the optimum set of CHs and construct clusters accordingly based on the location and residual energy of devices. • Cooperative nodes selection algorithms for cluster-based capillary networks. By utilising the spacial diversity of cooperative communication, these algorithms select the optimum set of cooperative nodes to assist the CHs for the long-haul transmission. In addition, with the regard of evenly energy distribution in one-hop cluster-based capillary networks, the CH selection is taken into consideration when developing cooperative devices selection algorithms. The performance of proposed selection algorithms are evaluated via comprehensive simulations. Simulation results show that the proposed algorithms can achieve up to 20% network lifetime longevity and up to 50% overall packet error rate (PER) decrement. Furthermore, the simulation results also prove that the optimal tradeoff between energy efficiency and QoS provision can be achieved in one-hop and multi-hop cluster-based scenarios.
78

Compressive spectrum sensing in cognitive IoT

Zhang, Xingjian January 2018 (has links)
With the rising of new paradigms in wireless communications such as Internet of things (IoT), current static frequency allocation policy faces a primary challenge of spectrum scarcity, and thus encourages the IoT devices to have cognitive capabilities to access the underutilised spectrum in the temporal and spatial dimensions. Wideband spectrum sensing is one of the key functions to enable dynamic spectrum access, but entails a major implementation challenge in terms of sampling rate and computation cost since the sampling rate of analog-to-digital converters (ADCs) should be higher than twice of the spectrum bandwidth based on the Nyquist-Shannon sampling theorem. By exploiting the sparse nature of wideband spectrum, sub-Nyquist sampling and sparse signal recovery have shown potential capabilities in handling these problems, which are directly related to compressive sensing (CS) from the viewpoint of its origin. To invoke sub-Nyquist wideband spectrum sensing in IoT, blind signal acquisition with low-complexity sparse recovery is desirable on compact IoT devices. Moreover, with cooperation among distributed IoT devices, the complexity of sampling and reconstruc- tion can be further reduced with performance guarantee. Specifically, an adaptively- regularized iterative reweighted least squares (AR-IRLS) reconstruction algorithm is proposed to speed up the convergence of reconstruction with less number of iterations. Furthermore, a low-complexity compressive spectrum sensing algorithm is proposed to reduce computation complexity in each iteration of IRLS-based reconstruction algorithm, from cubic time to linear time. Besides, to transfer computation burden from the IoT devices to the core network, a joint iterative reweighted sparse recovery scheme with geo-location database is proposed to adopt the occupied channel information from geo- location database to reduce the complexity in the signal reconstruction. Since numerous IoT devices access or release the spectrum randomly, the sparsity levels of wideband spec-trum signals are varying and unknown. A blind CS-based sensing algorithm is proposed to enable the local secondary users (SUs) to adaptively adjust the sensing time or sam- pling rate without knowledge of spectral sparsity. Apart from the signal reconstruction at the back-end, a distributed sub-Nyquist sensing scheme is proposed by utilizing the surrounding IoT devices to jointly sample the spectrum based on the multi-coset sam- pling theory, in which only the minimum number of low-rate ADCs on the IoT devices are required to form coset samplers without the prior knowledge of the number of occu- pied channels and signal-to-noise ratios. The models of the proposed algorithms are derived and verified by numerical analyses and tested on both real-world and simulated TV white space signals.
79

Employee innovation of IoT applications: A framework to facilitate capability, opportunity, and intent

Sjölund, Markus January 2019 (has links)
Purpose: The purpose of this study was to augment the understanding for how an organisation can facilitate the creation of applications of the Internet of Things (IoT) through increased involvement of employees in the innovation process. Method: This was an explorative study utilising qualitative data that was collected from a single case. Data was collected from a process manufacturing facility owned by a market-leading company through a combination of methods: questionnaire, documentation, observation, and interviews. Findings: It was found that the employee innovation process occurs in eight stages: problem-identification and communication, and idea-generation, communication, assessment, prioritisation, assignment, and implementation. It was also found that to successfully innovate, employees require knowledge, time, and motivation. Further, seven enabling and six inhibiting factors of employee innovation were identified. The process, requirements, and factors were utilised to build a framework to facilitate employee innovation for applications of the IoT. Theoretical contributions: This study merged two rather young bodies of literature, IoT and employee innovation, in a novel way. Innovation related to the IoT is close to unexplored, and employee innovation has never been studied specifically related to the IoT. Further, the eight-stage process of employee innovation is also novel. Managerial implications: There now exists a framework that managers can utilise to facilitate employee innovation in general, and innovation for the IoT in particular. The findings of this study can act as guidance for managers seeking to involve their employees in the innovation process.
80

Strategy Development of SMEs in the Internet of Things era : Case Study on Chinese Enterprises

Yunli, Lu, Xiuting, Li January 2010 (has links)
<p>Internet of Things (IOT) has become the key theme of the world since 2009 and been considered as the third wave in the information industry after the waves of Computer, Internet and Mobile Radio Communication. It is expected to have a strong influence on small and medium companies (SMEs). However, little research on what and how the influence of IOT on the SME’s development can be found in the literature. The purpose of the thesis is to examine how IOT influences the organizational changes in SMEs. Finally, suggestions for strategy developments will be proposed to assist the SMEs in making their organization changes successfully. Two main models are applied for this part: change model (OD model) and business model. Moreover, the SWOT theory is adopted to identify the SMEs position in IOT era. We collect the primary data through launching the survey on internet. After data documentation, we apply “Approximation of the Probability Hypothesis Testing” Method to conduct data analysis. After researching, we found out the IOT brings “revolution” change to the Logistics of SMEs while only “adapting” change for Manufactures’ business development. Compare to logistic industry, the manufacturing SMEs seldom adopts IT technologies for their selling channel because they are lacking of resources and knowledge for the new technologies. We suggest the logistic SMEs should establish logistic network between the logistic companies to enhance information and resource integration. For the manufacturing SMEs should apply knowledge management and change the companies into learning organizations. In future, IOT will bring radical changes for manufacturers, which are the biggest area with application of IOT technology. Nevertheless, the logistics industry might go out of fashion. In other words, logistics industry may die out or change to other functions.</p>

Page generated in 0.0315 seconds