Dissertations / Theses on the topic 'IoT availability'

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1

Andersson, Sebastian, and Oliver Josefsson. "On the assessment of Denial of Service vulnerabilities affecting smart home systems." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20717.

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IoT is an abbreviation of the term Internet of Things. The term describes everydayitems such as light bulbs that are connected to the Internet. IoT is a field that isgrowing very quickly with some researchers and industry leaders predicting thatthere will be up to 200 billion connected IoT devices in the world by 2020. Many IoTdevices are developed by smaller companies looking to capitalize on a specific needin the market. Because of this, the companies may favor launching a product as fastas possible which could mean that the devices may have not been adequately testedfor different vulnerabilities.The IoT and Smart Home market is currently experiencing rapid growth and all signspoint towards that continuing in the future. This thesis focuses on testing forvulnerabilities to Denial of Service attacks in common-off-the-shelf IoT devices thatcan be found in a smart home environment. The purpose of this thesis is to createmore knowledge about the vulnerabilities that can be found in Internet connecteddevices that are used daily.This thesis includes experiments using OpenVAS, which is a vulnerability scannerdeveloped by Greenbone Security used to test for vulnerabilities to Denial of Serviceattacks in IoT devices. The devices that are tested are Sony PlayStation 4, IKEATrådfri Smart Lighting, Google Chromecast (First Generation), Apple TV (ThirdGeneration) and D-Link DCS-930LB Wi-Fi IP-Camera. The firmware/software of allthe devices are updated as of April of 2019.The results of the conducted experiments show that all the tested devices besidesChromecast and IKEA Trådfri had vulnerabilities to Denial of Service attacks.PlayStation 4 was the device with the highest amount of vulnerabilities (9) and thevulnerability with highest possible severity (10.0). The effects of a Denial of Serviceattack range from an annoyance, when a gaming console is unavailable, to a securityrisk when an IP camera can be temporarily disabled.
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2

Simon, Nordsvan. "Counteracting Availability: Giving Control Back to Players Within Online Gambling." Thesis, Umeå universitet, Institutionen för informatik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-172778.

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Gambling has become ever more available and begun to employ more techniques, such as gamification, in order to engage their players. Today, Gambling with the use of your computer or smartphone is not deemed very different from playing any other kind of game. This shortens the availability cascade, or chain of events, that in the context of Gambling can ultimately lead to severe economical or social consequences for the players. This thesis seeks to find out how the increased availability can be counteracted by giving control back to the players through the use of personal informatics as well as if, and if so how, the social aspect of Gambling affects responsibility and the perceived experience. By conducting in-depth interviews with 20 participants I gained insights into what would assist them in maintaining control as well as their perception of Gambling. In order to evaluate these findings they were, in conjunction with related research, translated into a design concept. The results of the evaluations of this design suggest that many of the same techniques used to increase engagement with Gambling can also be utilized to counteract the increased availability. The prospects for future research are outlined.
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Somasiri, L. L. W. "A mixed ion-exchange resin procedure for assessing nutrient availability in temperate and tropical soils." Thesis, University of Aberdeen, 1991. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU033914.

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A multi-element soil extraction procedure (P, K, Mg, and Ca) using a mixed cation/anion exchange resin has been developed and its performance evaluated. Ion uptake to and recovery from the resin were highly reproducible over the concentration ranges typically experienced in soil. The effects on the overall reproducibility of changing various experimental parameters such as soil:water:resin ratios were quantified. Plant nutrient uptake and yield parameters obtained from either field (coconut) or pot (rye-grass) experiments using tropical or temperate soils have been used to evaluate the predictive capabilities of the proposed method. Comparisons with existing more widely acceptable soil extractants are made. The proposed method generally gave highly significant correlations with crop data which were independent of soil type. The possibility of including a simultaneous multi-element analytical step, which greatly increases the overall advantages of the resin procedure, has also been assessed.
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Heißler, Clara Charlotte [Verfasser]. "Working after hours, sharing availability expectations, and interrupting yourself: Extending perspectives on ICT-related concepts in research / Clara Charlotte Heißler." Kassel : Universitätsbibliothek Kassel, 2019. http://d-nb.info/1191202712/34.

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Summerhays, Jan C. R. "Effects of Non‐Surface‐Disturbing Treatments for Native Grass Revegetation on Cheatgrass (Bromus tectorum L.) Metrics and Soil Ion Availabilities." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1024.

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Several restoration methods intended to increase the success of aerially‐seeded perennial grasses were assessed to determine their effects on cheatgrass metrics and soil nutrient bioavailabilities. These methods were: 1) imazapic herbicide application (140 g ai ∙ ha‐1, 210 g ai ∙ ha‐1, and no application [control]), 2) vegetation manipulation treatments (50% sagebrush overstory thinning, 100% sagebrush overstory thinning, sagebrush overstory and/or vegetative thatch burning, and no manipulation [control]), and 3) alternative seeding treatments (aerial seeding with raking, aerial seeding with activated carbon [AC] addition, aerial seeding with sucrose addition, and regular aerial seeding [control]). Treatments were arranged in 3‐way factorial designs, which allowed main effects and interactions between treatments to be assessed. Responses were followed for two growing seasons following treatment. Main effects of treatments and their interactions on cheatgrass metrics are described in Chapter 2. Herbicide reduced cheatgrass weights and tiller and spikelet numbers in 2009, but these variables were greater than in no‐herbicide plots in 2010. Burning decreased cheatgrass densities but increased weights and tiller and spikelet numbers in both years. One hundred percent sagebrush thinning resulted in greater cheatgrass weights and tiller and spikelet numbers in both years and greater densities in 2010. Sucrose addition decreased cheatgrass weights and tiller and spikelet numbers in 2009, but increased these variables in 2010. An interaction between AC and herbicide treatment was observed, with AC potentially sequestering and lessening the negative effect of herbicide on cheatgrass. Aerial seeding with raking and 50% sagebrush thinning treatments were not found to significantly affect cheatgrass either year. The effects of treatments (herbicide, 50% sagebrush thinning, aerial seeding on snow, and aerial seeding with raking treatments omitted) on soil nutrient availabilities are described in Chapter 3. We used ion exchange resin (IER) membrane probes to measure extractable quantities of 15 ions over three time periods following treatment applications. Burning resulted in short‐term increases in many soil nutrient availabilities, including nitrate (NO3 ‐), phosphate (H2PO4 ‐), and sulfate (SO4 2‐). Sucrose addition reduced availabilities of NO3 ‐ and H2PO4 ‐ during the first winter and growing season. No changes were detected with AC addition or 100% sagebrush thinning during any sampling time.
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6

Gherardi, Mark James. "Availability and management of manganese and water in bauxite residue revegetation." University of Western Australia. Soil Science and Plant Nutrition Discipline Group, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0038.

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[Truncated abstract] Industrial processing to refine alumina from bauxite ore produces millions of tonnes of refining residue each year in Australia. Revegetation of bauxite residue sand (BRS) is problematic for a number of reasons. Harsh chemical conditions caused by residual NaOH from ore digestion mean plants must overcome extremely high pH (initially >12), saline and sodic conditions. At such high pH, manganese (Mn) is rapidly oxidised from Mn2+ to Mn4+. Plants can take up only Mn2+. Thus, Mn deficiency is common in plants used for direct BRS revegetation, and broadcast Mn fertilisers have low residual value. Added to this, physical conditions of low water-holding capacity and a highly compactable structure make BRS unfavourable for productive plant growth without constant and large inputs of water as well as Mn. However, environmental regulations stipulate that the residue disposal area at Pinjarra, Western Australia, be revegetated to conform with surrounding land uses. The major land use of the area is pasture for grazing stock. Hence, pasture revegetation with minimum requirement for fertiliser and water application is desirable. This thesis investigates a number of avenues with potential for maintaining a productive pasture system on BRS whilst reducing the current level of Mn fertiliser and irrigation input. Emphasis was placed on elucidation of chemical and physical factors affecting Mn availability to plants in BRS
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7

duarte, natasha. "draft Nitrogen form and availability measured with ion exchange resin in a loblolly pine stand on the Coastal Plain of North Carolina." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-05142002-221956/.

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Understanding how management affects long-term site productivity will help sustain forest productivity. In 1991, the USDA Forest Service installed the Long-Term Soil Productivity study in the Croatan National Forest in Craven County, NC. The study objectives were to compare indices of plant-available inorganic N from ion-exchange resin (IER) in bead and membrane form and aerobic incubations in a 8-week study, and to analyze the effects of harvest intensity and site preparation on N availability and tree growth ten years after planting. Site treatments included three levels of organic matter removal and two levels of compaction arranged in a strip-plot design replicated in three blocks. Block 1 consisted primarily of Goldsboro soil, while Blocks 2 and 3 consisted of Lynchburg. The two-month study showed no correlation of the N availability among the three techniques. The short duration of the study and the low soil fertility at the site may have contributed to the lack of correlation, indicating that the two forms of IER may not be equally effective at low nutrient concentrations. Through the 2001 growing season, IER membranes were used to measure soil NO3 and NH4 biweekly. Non-linear analysis indicate that total inorganic N recovered from the IER membranes was significantly influenced by interactions between block, organic matter removal treatment and compaction level (p=0.005). Total basal area of loblolly pines was significantly impacted by block (p=0.015) and organic matter removal treatment (p=0.032). At year ten, treatment effects can still be seen on both soil processes and tree productivity.
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8

Medina-Ross, Jose Antonio. "Study on phosphorus desorption and availability to soybean (Glycine max L.) in two phosphorus rich Gleysolic soils under different tillage and fertilization practices." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21609.

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Soil phosphate is essential for the development and maturity of crops. Plants absorb phosphate from the soil solution which is continuously replenished by fertilizer application and/or desorption from the soil solid phase. Anion exchange membranes (AEMs), act in a similar way to plant roots, adsorbing P from soil solution. Desorption of available P was studied in 1997 on two Gleysolic soils rich in P, a Ste. Rosalie clay soil and a Duravin sandy loam soil, using fluoride-saturated AEMs let in soil suspension for various contact periods. Determination of available P using these AEMs was compared to P extraction using the Mehlich III extractant for predicting P availability to soybean (Glycine max L.). Desorption from both soils, and subsequent adsorption by AEMs was found to decrease with time. A high P desorption rate was calculated for both soils with the Elovich equation. Different chemical and physical characteristics such as pH, Mehlich III extractable Al, Fe and Ca, sand and clay content were in some cases, positively correlated and in other cases, negatively correlated with various contact periods for both soils. The use of AEMs better predicted P availability than the Mehlich III extractant, although the most important asset of using AEMs is that they showed the desorption effect over time on P availability. It was observed that P remobilization from the vegetative part to the grain was reduced due to the high P concentration in both soils.
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Lindell, Emma, and Josefin Stolt. "Anställdas upplevelse av hur dagens gränslösa digitala arbete förskjuter balansen mellan privatliv och arbetsliv." Thesis, Högskolan i Gävle, Psykologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29653.

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Syftet med studien var att undersöka om och hur anställda upplever att dagens gränslösa digitala arbete förskjuter balansen mellan privatliv och arbetsliv. Genom en kvalitativ metod utgick studien från åtta semistrukturerade intervjuer som genomfördes på ett företag beläget i Mellansverige. Intervjumaterialet analyserades sedan utifrån en induktiv tematisk analys där tre teman identifierades; kontroll över informationsflödet, organisationskultur med undertemat ledarskap samt slutligen temat flexibilitet. Utifrån studiens resultat framkom det att gränsen mellan privatliv och arbetsliv har förskjutits av dagens gränslösa digitala arbete då respondenterna tenderade att kontrollera det arbetsrelaterade informationsflödet i huvudsak via mail utanför arbetstid. En stark organisationskultur och ett ledarskap utan förväntningar på ständig tillgänglighet hos de anställda samt möjlighet till flexibla arbetstider underlättade för respondenterna att hantera den diffusa gränsdragning som uppstått i och med digitaliseringen och skapa en god work-life balance.
The aim of this study was to examine whether and how employees feel that today's boundless digital work shifts the balance between work and family life. Through a qualitative method, the study was based on eight semi-structured interviews which was carried out at a company located in Central Sweden. The collected material was analyzed using an inductive thematic analysis where three themes were identified; control over the stream of  information, organizational culture with subcategory leadership and the final theme flexibility. The results indicated that the boundary between work and family life has shifted by today´s limitless digital work, since the respondents controlled their work-related stream of information mainly through email outside working hours. An organizational culture and leadership without expectations of permanent availability and the possibility to use flexible working hours has made it easier for the respondents to handle the diffuse boundary that emerged with the advanced technology and to create a good work - life balance.
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CHEN, CHING-WEI, and 陳慶維. "Security and Availability Enhancement by Using the Four Layer Architecture of IoT." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/80865490723674489307.

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博士
朝陽科技大學
資訊管理系
104
Currently, information technology is developing rapidly, and resulting in the vigorous development of the IPv6. The new concept of the future network is applied to the smart objects which have sensing, networking and computing abilities, and the ability to transfer data between the objects; the novel network environment is called the Internet of Things (IoT). The past researches of the middleware layer in the IoT have not discussed inaccurate information, large and complex information and data insecurity issues. Thus, a framework of middleware is proposed to solve these problems through data filtering and integration to draw on meaningful information. This study used the concept of security level agreements to reduce the risk of data being subject to malicious attacks, as well as the computational cost of data encrypted in the perception layer. And the digital signature is used to establish a lightweight security mechanism between the application and the perception layer. Through the framework of the middleware layer, the identity of the application and the perception layer will have a verification and non-repudiation, and the security of the IoT can be obtained. This study proposed Three-Phase Scheduling (3PS) under a cloud computational resource layer, to improve the effectiveness of the system. Thereby, each task to be performed can be assigned to the appropriate resources, while improving the load on each service node and reducing the waste of resources.
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11

Rashid, Adnan. "Resilient IoT Systems – Issues and Solutions." Doctoral thesis, 2022. http://hdl.handle.net/2158/1263242.

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The Internet of Thing (IoT) has been one of the main focus areas of the research community in recent years, their peculiar requirements help net- work administrators to design and ensure the functionalities and resources of each device. Generally, two types of devices—constrained and uncon- strained devices—are typical in the IoT environment. Devices with limited resources—for example, sensors and actuators—are known as constrained de- vices. The unconstrained devices include gateways or border routers. Such devices are challenging in terms of their deployment because of their con- nectivity, channel selection, multiple interfaces, local and global address as- signment, address resolution, remote access, mobility, routing, border router scope, and security. To deal with these peculiar services, the availability of the IoT system ensures that the desired network services are available even in the presence of denial-of-service attacks, and the use of the system has become a difficult but mandatory task for network designers. To this end, I present a novel design for Wireless Sensor Networks (WSNs) which is the subsystem of IoTs, to address these challenges by shifting mandatory functionalities from unreliable to reliable and stable domains. Moreover, energy conservation is another aspect that is one of the main constraints and the traditional IPv6 Neighbor Discovery (IPv6-ND) is not designed nor suitable to cope with it. In spite of that, non-transitive wireless links and the use of heavy multicast transmission make it inefficient and sometimes impractical in a Low-Power and Lossy Network (LLN). Due to these peculiarities, significant work has been done by the Internet Engineering Task Force (IETF) to optimize IPv6-ND, known as IPv6 over Low power Wireless Personal Area Network - Neighbor Discovery (6LoWPAN-ND). The implementation of the 6LoWPAN-ND protocol in mesh-under works totally opposite to its main purpose because it reduces the multicast transmission but increases the unicast transmission in a drastic way. On the other hand, IPv6-ND works in a reactive way but the network resilience in terms of re- liability and robustness becomes questionable. Obtained results prove to answer a few questions. For example, is there a need for a 6LoWPAN-ND protocol for a given LLN or not? What would be the benefits or drawbacks if we utilize it? What will happen if we are not interested to adopt this protocol for LLNs and keep using the IPv6-ND protocol? All these questions addresses in terms of IoT resiliency. Another aspect is the availability of the application services and user privacy in IoT systems. Due to the drastic increase of IoT devices, increasing demand for application services with strict Quality of Service (QoS) requirements. Therefore, service providers are dealing with the functional integration of the classical cloud computing architecture with edge computing networks. However, considering the limited capacity of the edge nodes requires a proper virtual functions allotment to advance the user satisfaction and service perfection. However, demand prediction is crucial but essential in services management. High variability of application requests that result in inaccurate forecasts becomes a big challenge. The Federated learning methods provide a solution to train mathematical learning models at the end-user sites. Network functions virtualization leverages the IT virtualization technologies to virtualize entire classes of network node functions into building blocks that may connect, or chain together, to create and deliver communication services. To preserve the data security and maximize service provider revenue, I use the federated learning approach for the prediction of virtual functions demand in the Internet of Everything (IoE) based edge-cloud computing systems. Additionally, my work proposes a matching-based tasks allocation with some numerical results that validate the proposed approach by comparing it with a chaos theory prediction scheme. The services offered through IoT systems, much like any system on the Internet, must not only be studied and improved, they must be continuously monitored to ensure security and resilience. It is important to know what kind of services they provide, how they evolve, and what is the network performance? One of the most promising ways to enable continuous QoE monitor is to use a novel IPv6 extension header called Performance and Diagnostic Metrics (PDM) Destination Option header, defined in RFC8250. This IETF standard defines an optional header that is included in each packet to offer sequence numbers and timing information for measurement purposes. These measurements can be analyzed in real-time or later. Currently, PDM data is provided in clear text so malicious actors may be able to gather information for future assaults. The standard proposal, which is still being worked on, uses a lightweight handshake (registration procedure) and encryption to safeguard data. It also includes a list of additional performance measures that might be useful for further performance evaluation of IoT systems. My proposal uses the Internet Research Task Force (IRTF) Hybrid Public Key Encryption (HPKE) framework [23] to provide confidentiality and integrity to PDM data and is currently the candidate system to secure both PDMv2 [46] and Messaging Layer Security (MLS) [22].
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12

Lo, Ya-Ling, and 羅雅齡. "A Research on Designing an Availability and Security-ensured Authentication Model of IoT Control System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/nsd7xb.

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碩士
國立臺中科技大學
資訊工程系碩士班
104
Recently, Yang et al. enhanced the IoT control system by adding the backup terminal device, the status monitor device and the alarm module for availability and security. Service is provided by the backup terminal device when the main terminal device malfunctions or its status is not correct. Their authentication model uses hash function to protect identifiers of terminal devices and the challenge-response mechanism to resist synchronization attack, and parameters for authentication are stored in the distributed database for reliability. They claimed that their model ensured mutual authentication. After analyzing their model, we find that their authentication model possesses the following drawbacks: (1) In their model, mutual authentication is between the database and the terminal device. The reader device is not authenticated. (2) Default search is needed when the database wants to find the matched terminal device’s identifier. This approach places a heavy burden on the database. (3) An attacker can send a forged device-switching request because the origin of this request is not authenticated. In this thesis, we adjust the operation and requirements of the IoT control system and take user anonymity into consideration to propose an authentication model for the IoT control system. The proposed authentication model complies with the following requirements. (1) The computational load is light. (2) Default search is not needed. (3) The terminal device’s identifier is protected. (4) User anonymity is ensured. (5) The origin of a device-switching request can be authenticated. (6) A user (RFID tag), the reader, and the terminal device can authenticate each other. Via the proposed model, the IoT control system’s security can be ensured.
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HUANG, WEI-YUAN, and 黃暐原. "The Research and Implementation on Load Balance and High Availability Scheme of IoT Applications - An Example of Pacemaker and Mesos Cluster." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8h77e9.

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碩士
國防大學
資訊管理學系
105
With the Internet development and the mobile devices universal, Internet of Things (IOT) is becoming one of the most important research topics. Information of any person can be connected to any place at any time in the mainly concept of IOT. However, there are large number of intelligent devices to collect extremely huge data frequently in IOT, so scalability, flexibility and integration are the essential features of IOT platforms. Two new models and of load balancing and high availability are proposed to achieve these features in this research. There are some important indexes in these models. The response time, the residual performance, and the data throughput are defined and derived in this load balancing model. The failover-time and the high availability index are defined in the high availability model. In this research, an implementation of these models base on Mesos and Pacemaker, two open sources software of clusters' resource management, to verify the characteristics of the models. Finally, the results show that when some nodes fail, there will be other nodes can continue to provide services and balance the loading successfully in this integrated load balancing and high availability mechanisms for IOT.
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Salisbury, Steven Earl. "Ion exchange membranes and agronomic responses as tools for assessing nutrient availability." Thesis, 1999. http://hdl.handle.net/1957/33586.

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Winter wheat is commonly grown in rotation with leguminous and non-leguminous crops in the Willamette Valley. For agronomic, economic, and environmental reasons it is important to understand the influence of previous crops on availability of N and other nutrients. Objectives of this study were: (1) to evaluate the effects of long-term rotations on winter wheat response to N fertilizer, and (2) to evaluate the use of Plant Root Simulator���(PRS) probes for measuring soil N mineralization and N availability to winter wheat. Field experiments were conducted over three growing seasons in plots of `Stephens' soft white winter wheat at Hyslop farm. Plots receiving 0, 50, 100, 150 and 200 kg N ha����� at Feekes GS 4 were sampled to determine above ground N uptake, grain yield, and grain protein. In spring 1998, PRS probes were placed in 0 kg N ha����� plots and removed at one-week or two-week intervals. In autumn 1998, probes were placed in unfertilized plots and removed at 1-week, 4-week, and 8-week intervals. Probes measured the availability of NH������-N, NO������-N, K���, Ca�����, Mg�����, and P0��������-P. Grain yield and N uptake were greater for wheat following clover as compared to following oats. Three-year average fertilizer equivalent values calculated from N uptake and grain yield data were 44.5 kg N h����� and 49.0 kg N h�����, respectively. The similarity of these independent measurements suggest that differences in N availability were the primary reason for the rotation effect. PRS probes also detected rotational differences in N availability. Average N recovered by probes sampled at 1-week intervals indicated that there was 63% as much NO������-N available to wheat following oat as compared to clover. Wheat recovered 64% as much N following oats as compared to clover. This suggests that PRS probes are an effective method for predicting relative amounts of plant available N. PRS probes also detected rotational differences in plant available potassium. Agronomic responses are useful for assessing the availability of nutrients that are limiting plant growth. PRS probes, on the other hand, are effective for assessing the availability of both limiting and non-limiting nutrients.
Graduation date: 2000
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15

Masango, Michack Mandla. "The relationship between the use of ICT for instruction and learning and the availability of ICT resources." Diss., 2014. http://hdl.handle.net/2263/43170.

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South African schools appear to be far from attaining the strategic objectives of the White Paper 7 on e-Education of 2004. The use of ICT for instruction and learning in schools is hampered by contextual factors in South Africa. One factor hampering the use of ICT in South African schools is the availability of ICT resources. Despite a high degree of access to ICT at home, most schools do not have the relevant ICT resources that teachers can use for instruction and learning. The SITES 2006 technical coordinators dataset was used to determine the statistical significant difference of the joint frequencies of the number of years that schools have been using ICT for instruction and learning as well as the availability of ICT resources. An integrated qualitative-quantitative design was used to transform the dataset for the calculation of a two-way Chi-square. A two-way Chi-square was calculated for the joint frequencies as well as for the odds ratio to determine the effect size of the frequencies. Activity Theory was used as a “theoretical framework for the analysis and understanding of human interaction through the use of tools and artefacts” (Hashim & Jones, 2007). The extent of the use of ICT resources (tools) by teachers (subject) in instructing learners (object) determines the degree of success in education (outcome). Easy availability of ICT resources for use in instruction and learning should yield a positive, meaningful achievement in education.
Dissertation (MEd)--University of Pretoria, 2014.
lk2014
Science, Mathematics and Technology Education
MEd
Unrestricted
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Krsmanovic, Dejana. "Development of a property forecast tool for flexible compositions of Li-ion batteries, including raw material availability and price forming." Thesis, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-393488.

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In today's world full of rigorous government measures regarding the fuel economyand a large EV and smart device market emerging from it, batteries represent apioneering technology used as storage for renewable energies such as wind and solar.More precisely, the Li-ion family of batteries has experienced an exponential growthin sales. Having high energy density, these batteries are also well suited for mobiledevices such as wearables, smartphones, tablets, cameras, notebooks and electricvehicles.[1] However, the technology has not completely matured yet and there is stilla lot of space for improvements and new discoveries. This thesis considers thecomposition of lithium-ion batteries together with the global distribution andeconomical aspects of materials used. The components of Li-ion cells of different cellformats (e.g. 18650, 21700) were investigated together with their physical andchemical properties. Through this process, an interactive tool for calculating costs,cell parameters and quantity of active materials was developed. The main purpose ofthe tool was to enable a user to input data such as thicknesses of electrodes, togetherwith the capacity of the cell and output how much material is needed for suchelectrodes and what energy density is achieved. These parameters, such as the massof active material, were linked to a cost calculator, determining the costs of a singlecell. The calculator is useful for further research purposes on Li-ion batteries, as theinput variables can be modified in according to the user's preferences, whereas costdetermination is useful for sales planning and battery manufacturing.
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Duarte, Natasha. "Nitrogen form and availability measured with ion exchange resin in a loblolly pine stand on the coastal plain of North Carolina." 2002. http://www.lib.ncsu.edu/theses/available/etd-05142002-221956/unrestricted/etd.pdf.

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18

Shih, Yu-Na, and 施幼娜. "Using the Selective Ion Exchange Resin Extraction Method to Evaluate the Effect of Compost Amendments on the Availability and Phytotoxicity of Chromium (VI) in Soils." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/18813873168705636583.

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碩士
國立臺灣大學
農業化學研究所
92
Chromium in soil is presented in two forms: Cr(Ⅲ) cation and Cr(VI) oxyanions. Chromium(VI) is more toxic and mobile than Cr(Ⅲ). In this study, two kinds of composts (hog-dung compost and cattle-dung compost) were applied to investigate their effects on the decrease of availability of Cr(VI) in Cr(VI)-contaminated soils. Three representative soils of Taiwan [Pingchung (Pc), Chingchung (Cf), and Taikang (Tk)] and one Cr-contaminated soil [Changhua (Cc)] were used in this study. Three representative soils were added with K2Cr2O7 solutions to reach the level of 0, 175, 250, 400, and 500 mg Cr / kg respectively and gone through 3 drying and wetting cycles to prepare Cr(VI)-spiked soils. Composts were added with the three rates of 0, 50, and 150 g organic matter per kg soil into the Cr(VI)-spiked soils and one Cr-contaminated soil and incubated at 15℃ and field capacity for 20,40, and 60 days respectively. After incubation, the Cu-saturated selective ion exchange resin (DOWEX M4195) was used as an infinite sink to extract soil available Cr(VI). Results from this study indicate that the amounts of resin-extractable Cr(VI) decreased in the Cr(VI)-spiked soils after amendment with two kinds of composts and the extent of reduction increased with the increase of the length of incubation time after compost addition. With the same amount of compost application, cattle-dung compost had larger extent in reducing the amount of soil extractable Cr(VI) than hog-dung compost. For the Cr-spiked soils with the same level of Cr(VI) addition, because Tk-soil had the largest contents of resin-extractable Cr(VI) among the three Cr(VI) spiked soils, the amonts of decrease of resin-extractable Cr(VI) was larger in Tk-soil than those in Pc-soil and Cf-soil with the addition of composts and incubation for 60 days. In this study, Neubauer test was also used to investigate the effect of amending with composts on the growth of wheat seedlings in the Cr-spiked soils. The results show that the height and dry weight of wheat seedlings in the Cr-spiked soils decreased with the increase of amount of soil extractable Cr(VI) by the resins. It indicates that the growth of wheat seedlings was inhibited by the soil extractable Cr(VI). The extent of growth inhibition of wheat seedlings was significantly reduced when amending with composts into Cr(VI) spiked soils, resulting from reducing the soil available Cr(VI) by adding composts. The above results indicate that addition of composts can decrease the amount of soil available Cr(VI) and thus reduce the phytotoxicity of Cr of Cr(VI)-contaminated soils. In addition, for the Cr-contaminated soil (Cc-soil) with total Cr concentration of 3070 mg kg-1, the amount of resin-extractable Cr(VI) was very low and the growth of wheat seedlings on this soil was not inhibited, indicating that the amount of extractable Cr(VI) determined by the selective ion exchange resin method is more suitable than total amounts of Cr for evaluating the phytotoxicity of Cr in Cr-contaminated soils.
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19

Chisango, Grasia. "Technology challenges faced by rural women in the Eastern Cape province of South Africa: a case study in the Chris Hani Municipality." Diss., 2014. http://hdl.handle.net/10500/13872.

Full text
Abstract:
The study sought to explore technology challenges faced by some rural women in Intsika-Yethu and Emalahleni local municipalities, under the Chris Hani District Municipality, in the Eastern Cape Province of South Africa. Available literature reveals that some rural women in South Africa and other developing parts of the world face technology challenges. The study is qualitative and focuses on two municipalities. Thirty-two women participated in the study. Data were collected through in-depth interviews and focus group interviews. Data were presented, analysed and discussed according to the themes derived from the sub-research questions. It emerged from the study that while most women in both municipalities were aware of ICT, they are however facing ICT access challenges in most areas of the municipalities. The findings do not depict the South African government national ICT policy goals which realises the importance of technology in the integration of services for the development of rural areas. Designing intervention programs for secondary school girls and some rural women, as well as monitoring and evaluating ICT programs in rural areas are recommended.
Communication Science
MA ( Communication)
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