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An alternative roaming model inLoRaWANLamberg-Liszkay, János, Lisauskas, Tadas January 2018 (has links)
LoRaWAN is an open networking technology designed for IoT devices that al-lows wireless data transmission over longer ranges than some other wireless tech-nologies, like Wi-Fi or Bluetooth, for devices that are constrained in terms of size,price, and available power. The current design of roaming among networks in LoRaWANis heavily inspired by that of mobile networks, as the use of roaming agreementsis mandated. Roaming agreements create unnecessary administrative overhead thathinders deployments. A roaming model that is quicker and simpler to deploy couldsave money for current users, and could even attract new users to the technology.To circumvent the necessity of roaming agreements, a new, scalable and agreement-less roaming model should be proposed. In this thesis project a literature survey isconducted, investigating similar technologies to find hints or inspiration for a newroaming model. It is found that the broker software architecture pattern put in thecontext of roaming in LoRaWAN suits the requirements quite well, so the new roam-ing model has been developed based on that. A software simulation has been imple-mented to gather data regarding the scalability of the model. It has been found thatthe proposed model is both scalable, and agreement-less.
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An actor-network approach to understanding the implementation of mobile phone-based innovations in less developed countriesEzenwa, Chioma January 2017 (has links)
This thesis aims to assess the usefulness of actor-network theory (Latour, 2005) in understanding the process of implementing mobile phone-based innovations within the broader government-led public sector in less developed countries. An examination of the literature on implementations of innovations involving mobile-phones suggests that previous studies have either focused on the social elements or the physical elements in isolation and have failed to consider how one influences the other. It is proposed that actor-network theory may be able to provide an alternative ontological perspective that bridges this social physical divide and allows the influence of the relationships between the human and the non-human elements to be taken into consideration. In order to assess this, the thesis utilises a single case study from its inception, through development, to its eventual end. The case in question, is the implementation of a mobile phone- based information system known as MADEX. This effort, is a nation-wide project made by the federal government of Nigeria to deploy this innovation within the government-led public health sector. MADEX was designed to support a nation-wide scheme known as the Midwives Service Scheme (MSS); a public sector initiative that was set up to address the United Nations Millennium Development Goals (MDG) relating to mother and child health. The main objective of MADEX in its initial stages was to enable the routine reporting of maternal health information from primary health facilities across the country up to the national level (NPHCDA) where this information is required by public health administrators for action - that is regular and timely monitoring of key maternal and child health indicators as well as strategic planning and the setting of priorities. The expectation was that, MADEX will bring about increased information accessibility for monitoring and planning, ensure global transparency and accountability in the area of maternal and child health statistics and promote m-health activities. An interpretive approach using qualitative methods was adopted in this research to obtain and analyse the data acquired through interviews. These interview, were conducted with a total of about 75 participant from across the various levels of the public health system. Whilst initially these events are narrated using a traditional chronological format, the use of such a format hides the complex nature of the relationships that enable the case under study. Actor-network theory therefore provides a means of exposing some of this complexity and as a result can be regarded as a useful methodology for understanding mobile phone innovations deployed in the public sector of LDCs. In addition, the thesis shows that the actor-network perspective allows the process of implementing mobile-phone innovations, to be considered in a manner that demonstrates the complex interdependent relationships between the physical and the social dimensions as well as the impact of non-humans in shaping this process.
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A subtribo Ecliptinae less. (Heliantheae-Asteraceae) na Amazônia brasileiraSILVA, Genilson Alves dos Reis January 2008 (has links)
Asteraceae is considered the most abundant in the plant kingdom, encompassing nearly 23,000 species distributed in 1,535 genera and 17 tribes. Considered the largest tribe, Heliantheae contains approximately 4,000 species, nearly 200 to 300 genera and 35 subtribes; only Ecliptinae is greater, with 67 genera. This work is comprised of a taxonomical study of the subtribe Ecliptinae for the Brazilian Amazon, and presents descriptions, identification keys and phenophase data, arcas of occurrence and geographic distribution of taxa. The botanical material including dried herbarium specimens were obtained on loan firom the Emílio Goeldi Museum (MG), Eastern Amazon Embrapa (IAN), Amapá Institute of Studies and Research (HAMAB) and the National Amazon Research Institute (INPA), and crossreferenced with archives firom the Rio de Janeiro Botanical Garden (RB) and National Museum (R); analysis of the material was done using current methodologies utilized in plant taxonomy. In the Brazilian Amazon, the subtribe Ecliptinae is represented by 12 genera, 23 species and one variety. The genus Aspilia Thou. was most representative with seven species,
followed by AemeHa Rich., with five. AemeHa sp. nov. was described as a new species for science. Acmella uliginosa (Sw.) Cass., Melanthera nívea (L.) Small., Spilanthes nervosa Chod. e Tilesia baccata var. discoidea (S.F. Blake) Pruski are new references for the Eastern Amazon. Melanthera latifolia (Gardn.) Cabrera and Aspilia camporum Chod. are new references for Rondônia. The species Wedelia calycina Rich. in Pers. is cited as a new reference for Acre and Roraima states. / Asteraceae é considerada a família mais numerosa do reino vegetal, compreendendo cerca de 23.000 espécies, distribuídas em 1.535 gêneros e 17 tribos. Considerada a maior tribo, Heliantheae possui aproximadamente 4.000 espécies, cerca de 200 a 300 gêneros e 35 subtribos, com ocorrência parcialmente americana; dentre as subtribos, Ecliptinae é a maior, com 67 gêneros. O presente trabalho trata do estudo taxonômico da subtribo Ecliptinae para a Amazônia brasileira, apresentando descrições, chave de identificação e dados de fenofases, ambientes de ocorrência e de distribuição geográfica dos táxons. O material botânico foi obtido através de empréstimos das exsicatas dos herbários do Museu Paraense Emílio Goeldi (MG), da Embrapa Amazônia Oriental (IAN), Instituto de Estudos e Pesquisas Tecnológicas
do Amapá (HAMAB) e do Instituto Nacional de Pesquisas da Amazônia (IMPA) e consultas aos acervos do Jardim Botânico do Rio de Janeiro (RB) e Museu Nacional (R); a análise do material seguiu a metodologia usual para trabalhos de taxonomia vegetal. Na Amazônia brasileira, a subtribo Ecliptinae está representada por 12 gêneros, 23 espécies e uma variedade. O gênero Aspilia Thou. foi o mais representativo com sete espécies, seguido de Acmella Rich. com cinco. AemeHa sp. nov. foi descrita como nova espécie para a ciência. AemeHa uliginosa (Sw.) Cass., Melanthera nívea (L.) Small., Spilanthes nervosa Chod. e Tilesia baccata var. discoidea (S.F. Blake) Pruski são novas referências para a Amazônia Oriental. Melanthera latifolia (Gardn.) Cabrera e Aspilia camporum Chod. são novas referências para Rondônia. A espécie Wedelia calycina Rich. in Pers. é citada como nova referência para os estados do Acre e Roraima.
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Icke dödande vapen : Försvarsmaktens senaste verktyg i internationella insatser / Non-lethal weapons : The Swedish Armed Forces’ latest tool in international operationsKarlsson, Jens January 2009 (has links)
<p>Due to the increasing international operations for the Swedish Armed Forces these new types of opponents needs new tools to cope with these commitments. A couple of years ago the Swedish Armed Forces had no non-lethal weapons, but today the Swedish soldier has a number of tools to choose from.</p><p>The purpose of this paper is for the reader to get a presentation of which non-lethal weapons are used today by the Swedish Armed Forces and a sample of what non-lethal weapons are out on the market today. My main question is <em>which non-lethal weapons do the Swedish Armed Forces’ miss in their non-lethal capabilities set.</em></p><p>I have collected information from a wide selections of sources like reports from the Swedish Defence Research Agency, the Swedish Armed Forces’ own regulations and the Internet. The information is then processed and divided into five chapters: The development of non-lethal weapons, description of technologies, non-lethal weapons in the Swedish Armed Forces, Non-lethal weapons on the market and Results.</p><p>This paper is limited to handheld, portable and man to man non-lethal weapons, all non-lethal weapons in the Swedish Armed Forces or on the international market are not covered.</p><p>My conclusion is that the Swedish Armed Forces should acquire three 40 mm projectiles, one 12-gauge projectile and one TASER®.</p>
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Icke dödande vapen : Försvarsmaktens senaste verktyg i internationella insatser / Non-lethal weapons : The Swedish Armed Forces’ latest tool in international operationsKarlsson, Jens January 2009 (has links)
Due to the increasing international operations for the Swedish Armed Forces these new types of opponents needs new tools to cope with these commitments. A couple of years ago the Swedish Armed Forces had no non-lethal weapons, but today the Swedish soldier has a number of tools to choose from. The purpose of this paper is for the reader to get a presentation of which non-lethal weapons are used today by the Swedish Armed Forces and a sample of what non-lethal weapons are out on the market today. My main question is which non-lethal weapons do the Swedish Armed Forces’ miss in their non-lethal capabilities set. I have collected information from a wide selections of sources like reports from the Swedish Defence Research Agency, the Swedish Armed Forces’ own regulations and the Internet. The information is then processed and divided into five chapters: The development of non-lethal weapons, description of technologies, non-lethal weapons in the Swedish Armed Forces, Non-lethal weapons on the market and Results. This paper is limited to handheld, portable and man to man non-lethal weapons, all non-lethal weapons in the Swedish Armed Forces or on the international market are not covered. My conclusion is that the Swedish Armed Forces should acquire three 40 mm projectiles, one 12-gauge projectile and one TASER®.
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DSP-Based Sensor-less Permanent Magnet Synchronous Motor Driver With Quasi-Sine PWM for Air-Conditioner Rotary CompressorLiu, Li-hsiang 03 August 2012 (has links)
This thesis presented a sensor-less permanent magnet synchronous motor (PMSM) driver for controlling air-conditioner rotary compressor speed. In this thesis, a quasi-sine pulse-width modulation (PWM) driving method was proposed. Furthermore, the current feedback control scheme and rotor magnet pole position detection were included. The system structure was implemented by using a digital signal processing (DSP) platform. The proposed driving scheme was compared with the square-wave driving without current feedback and six-step square-wave driving method with current feedback. Moreover, the passive and shunt semi-active power factor correction (PFC) technique were researched for the air-conditioner application. Experimental results demonstrated that the system power factor could be improved by the proposed shunt semi-active PFC method. Besides, the proposed sensor-less quasi-sine PWM driving method implemented in an air-conditioner compressor driver was capable of reducing the magnitude of rotational speed ripples, compressor vibration, and system power consumption.
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Internet Use and Economic Development: Evidence and Policy ImplicationsMacdougald, Joseph J 01 January 2011 (has links)
This dissertation explores how Internet use impacts four different measures of economic development using several econometric techniques on multi-country panel data. The economic development outcomes investigated are: per capita GDP, per capita export revenues, per capita market capitalization, and societal well-being as measured by the United Nations Human Development Index (HDI). Data from the World Bank, the International Telecommunication Union, and the United Nations -covering 202 countries over the period 1996 to 2007- are combined to allow for empirical investigation using dynamic panel data and finite mixture model estimation techniques on the total sample and subsamples stratified by country income level. The results suggest that countries benefit differently from increasing Internet use and the magnitude of the effect depends on the income level of the country. In low income countries, additional Internet use has a significant positive effect on per capita GDP and overall welfare, as measured by the HDI. Increasing Internet use has a significant positive effect on all four measures of economic development in countries that have achieved middle income status. Since Internet use affects economic development outcomes differently depending on the income level of the country, the policy recommendations must also vary according to the country's income level.
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A low-voltage, low-power CMOS bandgap referenceMurugeshappa, Ravi Gourapura 19 November 2010 (has links)
Bandgap reference circuits are used in a host of analog, digital, and mixed-signal systems to establish an accurate voltage reference for the entire IC. The most used CMOS implementation for voltage references is the bandgap circuit due to its high predictability, and low dependence of the supply voltage and temperature of operation. This work studies a CMOS implementation of a resistor-less bandgap reference, which consumes low power. The most relevant and traditional approaches usually employed to implement bandgap voltage references are investigated. The impact of process, power-supply, load and temperature variations has been analyzed and simulated. The functionality of critical components of the circuit has been verified through chip implementation. / text
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Coupled passive resonant circuits as battery-free wireless sensorsPasupathy, Praveenkumar 24 January 2011 (has links)
Detection and monitoring of the damage created by the corrosion of the steel reinforcement in concrete structures is a challenging and multidisciplinary problem. Economical monitoring strategy that is long-term and nondestructive requires low-cost, battery-free, wireless sensors. Our Electronic Structural Surveillance (ESS) platform uses battery-free passive resonant circuit (tag) as a sensor. The tag is magnetically coupled to an external reader coil. It is interrogated/read remotely in a non-contact (wireless) manner and the state of the sensor is determined from a swept frequency impedance measurement. When paired with the correct sensing element (transducer), the tag can be used for a variety of sensing applications for example, chemical & biochemical sensors. A circuit model of the reader and tag for such a universal battery-free wireless sensor platform is developed. The interaction between design and detection limit is examined. The dependence of the measured signal strength and read range on the various reader and tag circuit parameters is analyzed. Since the values of the circuit of the coils are dependent on their geometries, the effect of specific coil geometry is evaluated and design recommendations are made. / text
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Synthesis Of Porphyrin Containing Molecular Dyads For Radical-Cation GenerationHernandez-Alvarado, Edgardo Manuel January 2014 (has links)
The overall efficiency of photovoltaics is dictated by processes occurring within it. These processes include exciton formation, diffusion, dissociation and charge collection. This dissertation will focus around the fundamental issue of charge collection. In organic photovoltaics (OPVs) the rate of charge injection is dominated by the interaction between dissimilar materials, usually organic compound interacting with inorganic ones. In order to improve this rate of injection and, by direct consequence the efficiency of this process, fundamental knowledge of this organic-inorganic interface must be gained. In this work the focus will reside solely on creating molecules capable of probing the interface between the indium tin oxide (ITO) and the donor layer. At this interface, the usual charge transfer being transferred is the hole. Chapters 2 and 3 detail the synthesis and photophysical characterization of porphyrin-perylene diimide (Por-PDI) and porphyrin-fullerene (Por-C₆₀) molecular dyads. The idea behind these moieties is that covalent attachment of these species to ITO should lead to a robust ohmic contact. Since these molecular dyads are capable of producing charge-separated states after photoexcitation, they should have the capacity to produce a radical-cation in close proximity to the ITO. This will translate to a capacity for probing the dynamics of the hole injection at this interface. Studies performed demonstrate that in fact these dyads are capable of producing a charge-separated state upon photo-excitation. The lifetimes of these states were determine to be 35 ps and 3 ns for the Por-PDI and Por-C₆₀ respectively. Chapter 4 takes a different turn. It is focused on the application and extension of a solvent-free synthesis of metallated phthalocyanines (Pcs). Shown in chapter 4 is the synthesis of a series of metallated Pcs using various transition metals and group 3 elements. Photophysical and electrochemical investigation of these materials shows that they have near-infrared absorption and relative high HOMO levels making them potential candidates for OPV applications. In addition, they displayed non-linear optical behavior due to their highly polarizable pi-systems and the presence of axial susbtituents. Finally Chapter 5 describes the synthesis and characterization of porphyrin possessing rigid linkers. This chapter also shows the further directions in which the various ideas presented in this work could be driven.
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