This thesis investigates the possibilities of implementing a location awareness mechanism for the so-called lesswire localNavigator. The author claims that it is possible to implement such a mechanism within the given prerequisites and constraints, even though with today’s technology it may not be economically feasible. Due to the lesswire’s constraints: high accuracy (67%), high-resolution (12 m2) and no hardware modification allowed to the mobile device, the suggested scheme uses Time Difference Of Arrival technology (TDOA). The main advantage of TDOA, as stated in this thesis, is the fact that it is almost totally independent of the preferred wireless technology of the mobile device. TDOA technology therefore, can be applied to a wide range of wireless networks (primarily TDMA, CDMA, FDMA – based). A disadvantage of this scheme is the fact that the network infrastructure needs to be extremely well synchronized - which in turn implies higher costs. Depending on how the synchronization problem is solved, the proposed system may well be economically feasible in the near future.

Under det senaste decenniet har inomhuspositionering fått en ökad popularitet och stått i fokus för forskning och utveckling, eftersom det ger praktiska möjligheter till att spåra och navigera objekt och människor i inomhusmiljöer. Det finns ingen global lösning för inomhuspositionering baserat på en enstaka teknologi såsom det gör för utomhuspositionering med sin satellitbaserade globala positioneringssystem. Många inomhusteknologier står inför många utmaningar såsom låg positioneringsnoggrannhet samt dyr och stor hårdvara. Den här uppsatsen beskriver hur en simpel och kostnadseffektiv lösning, som addresserar problemen med noggrannheten och hårdvarukostnaden, genom en iterativ forskningsmetod, utvecklades. Vår lösning är ett ultraljudsbaserat passivt sändare-mottagare system som kombinerar multilateration som positioneringsteknik och tidsskillnad av ankomst (TDOA) som mätprincip för att beräkna en 3D-position inuti en 4x2x2 m testyta med en övergripande noggrannhet på 16 cm inom ett 95% konfidensintervall. Vi registrerade noggranna TDOA-värden med en komparatorkrets som fungerade som en amplitud-trigger. Det här tillvägagångssättet var mycket enklare än vad andra relaterade arbeten använde sig av, vilket var sampling för att bearbeta inkommande signaler från sändarna. / During the past decade, indoor positioning has gained more popularity and has become a focus of research and development as it provides practical possibilities to track and navigate objects and people in indoor environments. There is no overall solution for indoor positioning based on a single technology like the solution for outdoor positioning with its satellite-based global positioning system. Many indoor positioning technologies today face many challenges such as low positioning accuracy, expensive and large hardware. This thesis describes how a simple and cost-effective solution, that addresses the problem of accuracy and space cost with regards to hardware being used, was developed through an iterative research methodology. Our solution is an ultrasound-based passive receiver-transmitter system that combines multilateration as a positioning technique and time difference of arrival (TDOA) as a measuring principle. This combination is used to calculate a 3D position within a 4x2x2 m test area with an overall accuracy of 16 cm within a 95% confidence interval. We registered accurate TDOA values with a comparator circuit that acts as an amplitude trigger. This approach was much more simple than that of other related works which used sampling to process incoming signals from the transmitters.

The Arterial Spin Labelling (ASL) method is a Magnetic Resonance technique used toquantify the cerebral perfusion. It has the big advantage to be non-invasive so doesn’tneed the injection of any contrast agent. But due to a relatively low Signal-to-NoiseRatio (SNR) of the signal acquired (only approximately 1% of the image intensity), ithas been hampered to be widely used in a clinical setting so far.The primary objective of this project is to make the method more robust by improvingthe quality of the images, the SNR, and by reducing the acquisition time. DifferentASL protocols with different sets of parameters have been investigated. The modificationsperformed on the protocol have been investigated by analyzing images acquired onhealthy volunteers. An optimized protocol leading to a good trade-off between the differentaspects of the method, has been suggested. It is characterized by a 3:43:44:0mm3with a two-segment acquisition.A more advanced ASL method implies the acquisition of images at different inversiontimes (TI), which is called the mutli-TI method. The influence of the range of TI used inthe method has been explored. An optimized TI range (from 410ms to 3860ms, sampledevery 150ms) has been suggested to make the ASL method as performant as possible.A numerical model and a fitting algorithm have been used to extract the informationon the perfusion from the images acquired. Different models have been investigated aswell as their influence on the reliability of the results.Finally, a criterion has been implemented to evaluate the reliability of the results sothat the clinician or the user of the method can figure out how much he can count onthe results provided by the method.

Yes / The issue of asset tracking in dense environments where the performance of the global positioning system (GPS) becomes unavailable or unreliable is addressed. The proposed solution uses a low-profile array of antenna elements (sensors) mounted on a finite conducting ground. A compact-size sensor array of six electrically small dual-band omnidirectional spiral antenna elements was designed as a front end of a tracker to operate in the 402 and 837 MHz spectrum bands. For the lower band, a three-element superposition method is applied to support estimation of the angle of arrival (AOA), whereas all six sensors are employed for the higher band. A low complexity and accurate AOA determination algorithm is proposed, the projection vector (PV), and this is combined with the array mentioned. Orthogonal frequency division multiplexing (OFDM) is integrated with the PV technique to increase the estimation resolution. The system was found to be suitable for installation on the roof of vehicles to localize the position of assets. The proposed system was tested for the tracking of nonstationary sources, and then two scenarios were investigated using propagation modeling software: outdoor to outdoor and outdoor to indoor. The results confirm that the proposed tracking system works efficiently with a single snapshot. / European Union Horizon 2020 Research and Innovation Program; 10.13039/501100009928 - Higher Committee for Education Development (HCED), Iraq

There is an urgent need to reduce emissions from maritime transportation to meet environmental targets set by international organizations and governments. To reduce emissions from maritime transportation, technical, market-based, and operational measures can be used. In this thesis, the focus is on operational measures, and in particular Just-in-Time arrival in the port call process. Just-in-Time arrival in the context of port calls refers to maintaining an optimal vessel sailing speed to arrive to the port when the availability of berth and other services are ensured. In earlier studies, the estimated fuel and emission savings potential of Just-in-Time arrival, is promising. Despite the promising potential of Just-in-Time, its implementation remains limited, with few real-world examples. The purpose of this thesis is to explore how to implement Just-in-Time arrival by studying coordination in the port call process.    Two research questions were formulated to address the purpose. The first aims to capture the potential benefits of implementing Just-in-Time arrival in port calls and the second aims to address what is required to implement Just-in-Time arrival in port calls. This thesis is based on two studies in the Swedish context. First, a quantitative study, in which Automatic Identification System data in combination with port call statistics and vessel-specific data were used to estimate the fuel and emission savings potential of Just-in-Time arrival. Second, a qualitative single case-study exploring the coordination mechanisms necessary for implementing Just-in-Time arrival in port calls was conducted.    The studies show that fuel and emission savings potential of Just-in-Time in previous studies is overestimated due to the assumptions used. Though, the implementation of Just-in-Time has potential to improve port call actors’ resource planning and utilization and increase the competitiveness of ports. This is because Just-in-Time arrival has the potential to aid actors in reaching mandatory emission reduction targets. To implement Just-in-Time arrival, it is necessary to coordinate the plans of actors. The required mechanisms to coordinate planning are pre-booking berth allocation policy and port community systems. The pre-booking policy implies booking time-slots for berths, facilitated by using the port community system. The port community system and the pre-booking policy enable the effective coordination of the planning processes of individual actors enabling Just-in-Time arrival in port calls. / Det är nödvändigt att minska utsläppen från sjöfartssektorn för att uppnå de klimatpolitiskamålen som har fastställts av internationella och nationella organisationer. För att minska utsläpp från sjöfarten och uppnå de klimatpolitiskamålen kan tekniska, policy, och operativa åtgärder användas. Fokus i denna avhandling är på operativa åtgärder, mer specifikt Just-in-Time ankomst vid hamnanlöp. Just-in-Time ankomst innebär att hålla en seglingshastighet som möjliggör ankomst till hamn vid den tidpunkt kajplatser och andra tjänster (exempelvis lotsning) är tillgängliga utan fördröjning. Tidigare studier visar att det finns en potential att spara bränsle och minska utsläpp genom att införa Just-in-Time ankomst. Trots potentialen är införandet av Just-in-Time ankomst begränsat i praktiken. Syftet med avhandlingen är att utforska hur Just-in-Time ankomst kan implementeras genom att studera koordineringen av aktörers aktiviteter under anlöpsprocessen.    Syftet uppnås genom att besvara två forskningsfrågor. Den första forskningsfrågan berör potentialen av införandet av Just-in-Time ankomst vid hamnanlöp. I den andra frågan undersöks hur olika koordineringsmekanismer kan användas för att koordinera hamnaktörerna för att realisera potentialen av Just-in-Time ankomst. Två studier har genomförts. Först gjordes en kvantitativ modellering för att uppskatta bränsle- och utsläppsbesparingar för Just-in-Time anlöp i Sverige, baserad på Automatic Identification System data, hamnanlöpstatistik samt fartygsdata. Därefter har en kvalitativ fallstudie genomförts som har utforskat hur olika koordineringsmekanismer kan användas för att koordinera enskilda aktörers planeringsprocesser under anlöpsprocessen samt undersöka potentialen av införandet av Just-in-Time ankomst.    Resultat visar att bränsle- och utsläppsbesparingspotentialen med Just-in-Time ankomst i tidigare studier ofta har överskattats på grund av antaganden som använts. Vidare framkom att implementering av Just-in-Time ankomst ha ett positivt inflyttande på aktörernas resursplanering- och utnyttjade och att hamnar kan öka sin konkurrenskraft tack vare sambandet mellan Just-in-Time ankomst och obligatoriska åtgärder för att minska utsläpp. För att kunna implementera Just-in-Time ankomst krävs förbättrad koordinering mellan aktörerna genom införandet av en förbokningspolicy av kajplatser. För att kunna förboka krävs förbättrad planerings och informationsdelning, det senare kan nås genom införandet av digitala informationsplattformar (port community system).

There is an urgent need to reduce emissions from maritime transportation to meet environmental targets set by international organizations and governments. To reduce emissions from maritime transportation, technical, market-based, and operational measures can be used. In this thesis, the focus is on operational measures, and in particular Just-in-Time arrival in the port call process. Just-in-Time arrival in the context of port calls refers to maintaining an optimal vessel sailing speed to arrive to the port when the availability of berth and other services are ensured. In earlier studies, the estimated fuel and emission savings potential of Just-in-Time arrival, is promising. Despite the promising potential of Just-in-Time, its implementation remains limited, with few real-world examples. The purpose of this thesis is to explore how to implement Just-in-Time arrival by studying coordination in the port call process. Two research questions were formulated to address the purpose. The first aims to capture the potential benefits of implementing Just-in-Time arrival in port calls and the second aims to address what is required to implement Just-in-Time arrival in port calls. This thesis is based on two studies in the Swedish context. First, a quantitative study, in which Automatic Identification System data in combination with port call statistics and vessel-specific data were used to estimate the fuel and emission savings potential of Just-in-Time arrival. Second, a qualitative single case-study exploring the coordination mechanisms necessary for implementing Just-in-Time arrival in port calls was conducted. The studies show that fuel and emission savings potential of Just-in-Time in previous studies is overestimated due to the assumptions used. Though, the implementation of Just-in-Time has potential to improve port call actors’ resource planning and utilization and increase the competitiveness of ports. This is because Just-in-Time arrival has the potential to aid actors in reaching mandatory emission reduction targets. To implement Just-in-Time arrival, it is necessary to coordinate the plans of actors. The required mechanisms to coordinate planning are pre-booking berth allocation policy and port community systems. The pre-booking policy implies booking time-slots for berths, facilitated by using the port community system. The port community system and the pre-booking policy enable the effective coordination of the planning processes of individual actors enabling Just-in-Time arrival in port calls. / Det är nödvändigt att minska utsläppen från sjöfartssektorn för att uppnå de klimatpolitiskamålen som har fastställts av internationella och nationella organisationer. För att minska utsläpp från sjöfarten och uppnå de klimatpolitiskamålen kan tekniska, policy, och operativa åtgärder användas. Fokus i denna avhandling är på operativa åtgärder, mer specifikt Just-in-Time ankomst vid hamnanlöp. Just-in-Time ankomst innebär att hålla en seglingshastighet som möjliggör ankomst till hamn vid den tidpunkt kajplatser och andra tjänster (exempelvis lotsning) är tillgängliga utan fördröjning. Tidigare studier visar att det finns en potential att spara bränsle och minska utsläpp genom att införa Just-in-Time ankomst. Trots potentialen är införandet av Just-in-Time ankomst begränsat i praktiken. Syftet med avhandlingen är att utforska hur Just-in-Time ankomst kan implementeras genom att studera koordineringen av aktörers aktiviteter under anlöpsprocessen.    Syftet uppnås genom att besvara två forskningsfrågor. Den första forskningsfrågan berör potentialen av införandet av Just-in-Time ankomst vid hamnanlöp. I den andra frågan undersöks hur olika koordineringsmekanismer kan användas för att koordinera hamnaktörerna för att realisera potentialen av Just-in-Time ankomst. Två studier har genomförts. Först gjordes en kvantitativ modellering för att uppskatta bränsle- och utsläppsbesparingar för Just-in-Time anlöp i Sverige, baserad på Automatic Identification System data, hamnanlöpstatistik samt fartygsdata. Därefter har en kvalitativ fallstudie genomförts som har utforskat hur olika koordineringsmekanismer kan användas för att koordinera enskilda aktörers planeringsprocesser under anlöpsprocessen samt undersöka potentialen av införandet av Just-in-Time ankomst.    Resultat visar att bränsle- och utsläppsbesparingspotentialen med Just-in-Time ankomst i tidigare studier ofta har överskattats på grund av antaganden som använts. Vidare framkom att implementering av Just-in-Time ankomst ha ett positivt inflyttande på aktörernas resursplanering- och utnyttjade och att hamnar kan öka sin konkurrenskraft tack vare sambandet mellan Just-in-Time ankomst och obligatoriska åtgärder för att minska utsläpp. För att kunna implementera Just-in-Time ankomst krävs förbättrad koordinering mellan aktörerna genom införandet av en förbokningspolicy av kajplatser. För att kunna förboka krävs förbättrad planerings och informationsdelning, det senare kan nås genom införandet av digitala informationsplattformar (port community system).

No description available.

The Federal Aviation Administration (FAA) is continuously assessing the operational performance of the National Airspace System (NAS), where they analyze trends in the aviation industry to help develop strategies for a more efficient air transportation system. To measure the performance of various elements of the aviation system, the FAA and the International Civil Aviation Organization (ICAO) developed nineteen key performance indicators (KPIs). This dissertation contains three research studies, each written in journal format, addressing select KPIs. These studies aim at answering questions that help understand and improve different aspects of airport operational efficiency. In the first study, we model the flight times within the terminal airspace and compare our results with the baseline methodology that the FAA uses for benchmarking. In the second study, we analyze the efficiency of deicing operations at Chicago O'Hare (ORD) by developing an algorithm that analyzes radar data. We also use a simulation model to calculate potential improvements in the deicing operations. Lastly, we present our results of a clustering analysis surrounding the response of airports to demand and capacity changes during the COVID-19 pandemic. The findings of these studies add to literature by providing a methodology that predicts travel times within the last 100 nautical miles with greater accuracy, by providing deicing times per aircraft type, and by providing insight into factors related to airport response to shock events. These findings will be useful for air traffic management decision makers in addition to other researchers in related future studies and airport simulations. / Doctor of Philosophy / The Federal Aviation Administration (FAA) is the transportation agency that regulates all aspects of civil aviation in the United States. The FAA is continuously analyzing trends in the aviation industry to help develop a more efficient air transportation system. They measure the performance of various elements of the aviation system. For example, there are indicators focused on the departure phase of flights measuring departure punctuality and additional time in taxi-out. On the arrivals side, there are indicators that measure the additional time spent in the last 100 nautical miles of flight. Additionally, there are indicators that measure the performance of the airport as a whole such as the peak capacity and the peak throughput. This dissertation contains three research studies, each one aims at answering questions that help understand and improve a different aspect of airport operational efficiency. The first study is focused on arrivals where we model the flight times within the last 100 nautical miles of flight. Our model incorporated factors such as wind and weather conditions to predict flight times within the last 100 nautical miles with greater accuracy than the baseline methodology that the FAA currently uses. The resulting more accurate benchmarks are important in helping decision makers, such as airport managers, understand the factors causing arrival delays. In the second study, we analyze the efficiency of deicing operations which can be a major source of departure delays during winter weather. We use radar data at Chicago O'Hare airport to analyze real life operations. We developed a simulation model that allowed us to recreate actual scenarios and run what-if scenarios to estimate potential improvements in the process. Our results showed potential savings of 25% in time spent in the deicing system if the airport changed their queueing style towards a first come first served rather than leaving it for the airlines to have their separate areas. Lastly, we present an analysis of the response of airports to demand and capacity changes during the COVID-19 pandemic. In this last study, we group airports by the changes in their throughput and capacity during two time periods. The first part of the study compares airports operations during 2019 to the pandemic during the "shock event" in 2020. The second part compares the changes in airports operations during 2020 with the "recovery" time period using data from 2021. This analysis showed which airports reacted similarly during the shock and recovery. It also showed the relationship between airport response and factors such as what kind of airlines use the airport, airport hub size, being located in a multi-airport city, percentage of cargo operations. The results of this study can help in understanding airport resilience based on known airport characteristics, this is particularly useful for predicting airport response to future disruptive events.

Expanding the standard, single-well recording geometry used to monitor seismicity during hydro-fracture treatments could provide more accurate hypocenter locations and seismic velocities, improving general reservoir characterization. However, for the real, two-well data set obtained for this project, only S-wave picks were available, and testing resulted in anomalous hypocenter location behavior. This study uses a hypocenter location algorithm and both real and synthetic data sets to investigate how the accuracy of the velocity model, starting hypocenter location, recording geometry, and arrival-time picking error affect final hypocenter locations. Hypocenter locations improved using a velocity model that closely matched the observed sonic log rather than a smoothed version of this model. The starting hypocenter location did not affect the final location solution if both starting and final locations were between the wells. Two solutions were possible when the true solution was not directly between the wells. Adding realistic random picking errors to synthetic data closely modeled the dispersed hypocenter error pattern observed in the real data results. Adding data from a third well to synthetic tests dramatically reduced location error and removed horizontal geometric bias observed in the two-well case. Seismic event data recorded during hydro-fracture treatments could potentially be used for three-dimensional joint hypocenter-velocity tomography. This would require observation wells close enough to earthquakes to record P- and S-wave arrivals or wells at orientations sufficient to properly triangulate hypocenter locations. Simulating results with synthetic tests before drilling could optimize survey design to collect data more effectively and make analysis more useful. / Master of Science

Power transformers are one of the most important components in the electrical energy network. Extending transformer life is very economically valuable due to power outage. Therefore the development of instruments to monitor the transformer condition is of great interest. Detection of partial discharges (PDs) in power transformers is an effective diagnostic because it may reveal and quantify an important aging factor and provide information on the condition of the transformer. However, partial discharge diagnostics are still not effectively used for online monitoring of transformers because of the complexity of PD measurements and difficulties of discriminating of PDs and other noise sources. This thesis presents a further study of detection and location of partial discharges in power transformers based on previous work conducted at the Center for Photonics Technology (CPT) at Virginia Tech. The detection and positioning system consists of multiple extrinsic Fabry-Parot interferometric (EFPI) fiber acoustic sensors which can survive the harsh environment of oil-filled transformers. This thesis work is focused on optimal arrangement of multiple sensors to monitor and locate PD activities in a power transformer. This includes the following aspects. First, the sensor design requirements are discussed in order to successfully detect and accurately position the PD sources. In the following sections, Finite Element Method (FEM) is used to model the EFPI sensor fabricated at CPT. Experiments were conducted to measure the angular dependence of the frequency response of the sensor. It is shown that within the range of ±45º incident angles, the sensitivity varies by 3-5dB. Finally, the thesis demonstrates a PD positioning experiment in a 500 gallon water tank (R à H = 74" à 30" cylinder) using a hyperbolic positioning algorithm and time difference of arrival (TDOA). Finally we demonstrated that 100% of the positioning data is bounded by a 22.7à 4.1à 5.3 mm₃ cube, with a sensing range of 810 mm using the leading edge method with FIR filtering. / Master of Science