Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xvii, 83 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 79-83).

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At present runway congestion in the airline industry has reached a dangerously high level. The effects of this are very costly to all parties involved; US$5bn per year in Europe in 1989 alone. The problem demands urgent attention to accommodate the expected average growth in air transport of 6% per annum. up to the year 2000. It is becoming more and more obvious, however, that the construction of new runways is not a feasible option due to both political, environmental and physical space limitations within Europe. Alternative solutions are therefore required. In 1991 the European Regional Airlines Association, (ERA), produced a document entitled, 'The Vital Link', which outlined a number of ways in which regional aircraft could use their performance differences from the larger jet aircraft to help generate extra runway capacity from existing runways. Whilst the author was a member of the ERA operations committee he developed some of these ideas further. It is the objective of this thesis to examine the ideas developed by the author from both a theoretical and practical point of view to determine the feasibility of implementing them at congested European airports. Theoretical simulation modelling of Manchester, Zurich and Gatwick airports was undertaken using the FAA SIMMOD airport and airspace simulation model. This produced delay time savings and changes to peak hour movement rates which were used in a cost benefit analysis model to see whether or not the procedure would make a cost saving. The practical side of the thesis focused on an industry questionnaire to regional airlines, major airlines and airports to obtain their views on the new procedures and case studies of the procedures at Manchester and Gatwick airports. Results of the work show that whilst the procedures can effectively reduce operating delays they have a lessor impact on peak hour movement rates. Optimum use of the procedures is unique to individual airports and depends on the runway operation mode, TMA airspace configuration and the type and variability of the traffic mix. Actual application of the procedures will be dependant on political and environmental restrictions and likely future changes in regional airlines aircraft fleets.

The continuing growth in aviation has meant that the 35 largest airports in Europe reached saturation in 2005. The consequences have been increasing air traffic congestion, delays and associated costs. There is therefore a clear need to create more capacity. However, airports in particular and the air transport system in general are also subject to sudden fluctuations in demand and capacity. This research synthesizes the mechanisms of airport capacity fluctuations through the analytical formulation of concepts of capacity dynamics, capacity elasticities and capacity stability. It demonstrates the usability of these concepts through, firstly, a case study application to Brussels National Airport and, secondly, the development of a 'proof of concept' decision-support tool for strategic and tactical airport planning. Capacity dynamics and elasticities provide a performance indication as to how quickly capacity is able to change in response to fluctuations brought about by one or more capacity disrupters, whilst capacity stability provides airport planners with a measure of capacity robustness. These three concepts - capacity dynamics, elasticities and stability - contribute to a better a priori understanding of the airport system to be modelled. They demonstrate a better quantification of the impact and sensitivity of all the factors that affect runway capacity. It is also shown how the three concepts can assist in a better quantification of the risk of potential capacity fluctuation within the scope of airport planning. Based on this analytical formulation and quantification, mitigation should be an integral part of any effective airport plan in order to predict better the response to any given potential capacity degradation. It has been found that, from a capacity perspective, an airport becomes less stable the higher its level of performance. This capacity/stability paradox enables the ultimate goal of investment in capacity enhancement to be challenged, and it is legitimately questioned whether a similar investment would not be more worthwhile at secondary airports rather than at major airports.

Synchronization is a problem of fundamental importance for a wide range of practical communication systems including reading media, multi-user optical channels, synchronous digital communication systems, packet-switched communication networks, distributed computing systems, etc. In this thesis I study various aspects of communication over channels with symbol synchronization errors. Symbol synchronization errors are harder to model than erasures or substitution errors caused by additive noise because they introduce uncertainties in timing. Consequently, the capacity of channels subjected to synchronization errors is a very challenging problem, even when considering the simplest channels for which only deletion errors occur. I improve on the best existing lower and upper bounds for the capacity of the deletion channel using convex and stochastic optimization techniques. I also show that simply finding closed-form expressions for the number of subsequences when deleting symbols from a string is computationally prohibitive. Constructing efficient synchronization error-correcting codes is also a challenging task. The main result of the thesis is the design of a new family of codes able to correct several types of synchronization errors. The codes use trellis and modified versions of the Viterbi decoding algorithm, and therefore have very low encoding and decoding complexities. They also have high data rates and work for reasonably noisy channels, which makes them one of the first synchronization-correcting codes that have any chance of being used in practical systems. In the last part of the thesis, I show that a synchronization approach can solve the opportunistic spectrum access problem in cognitive radio, where cognitive users want to communicate in presence of legacy users to whom the bandwidth has been licensed. I also consider the amount of communication required to solve a large class of distributed problems where synchronization errors can occur. More precisely, I study how allowing the parties to solve the problems incorrectly with small probability can reduce the total amount of communication or the number of messages that need to be exchanged. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Science in Medicine in the field of Biokinetics. 21 June 2018 / Introduction: The purpose of this study was to describe the Endurance Index of automotive workers to determine aerobic capacity to sustain an 8 hour shift. The Endurance Index is the product of Work (in Joules) performed by muscles divided by Peak Heart Rate (in beats per minute). Since there is no clear method for determining full work tolerance (8 hour sustenance) for job specific endurance activities, a new scientific method is warranted. Methods: This was a retrospective study and 44 jobs were randomly selected. In those jobs there was a sample of 101 automotive workers (n = 94 males and n = 6 females). From the 44 jobs, there were 220 endurance activities/tests and peak heart rates and total work performed by muscles was described then these variables were used to calculate Endurance Index which was described for each endurance activity. Results: Peak HR had a mean of 139.85 ±20.96 (100 – 184bpm), total work had a mean of 9224.73 ±5826.04 (897.20 – 33 055) and EI had a mean of 67.14 ±42.88 (8 – 243.10). Total work and EI had significant (p < 0.00) and good positive correlation (r = 0.97). Peak HR and EI had significant (p < 0.01) and poor negative correlation (r = -0.18). Conclusion: The scientific rationale for using Endurance Index as an indicator for aerobic capacity is that the better conditioned an individual the more work that can be produced at lower relative heart rates compared to individuals who are poorly conditioned. So the more the work value and the lower the heart rate value, the better the index. In this study it was found that Endurance index is a good indicator of aerobic capacity since a positive correlation was found between total work and Endurance index and a negative correlation was found between peak heart rate during an endurance activity and Endurance Index. / MT 2019

No / Much of the environmental impact of buildings is associated with consumption of resources and generation of waste. The construction industry in Europe consumes over 70,000 million tonnes of a wide range of materials each year, and generates over 250 million tonnes of waste. Reducing waste is a priority for all the European Governments. Composite flooring formed by connecting the concrete slabs to the supporting steel beams has been widely used for many years throughout the world. The use of composite action between steel and concrete is well established as a cost-effective arrangement for floor systems in multi-storey steel frame building structures. Composite action between steel beams and concrete slabs through the use of shear connectors are responsible for a considerable increases in the load-bearing capacity and stiffness of the steel beams, which when utilised in design, can result in significant savings in steel weight and construction cost. However, shear connectors are welded through the steel decking and cast into the concrete; this made deconstruction and reuse of the steel components almost impossible. A demountable shear connector is developed and tested to assess its potential and suitability in term of replacing the welded through headed shear studs. Test results shown that these shear connectors can be easily demounted after test and have a similar capacity and behaviour of the welded shear connectors. In addition, test results showed that the new demountable shear connectors process high ductility in comparison with the welded shear connectors.

Secure multiparty computation refers to the problem where a number of users wish to securely compute a function on their inputs without revealing any unnecessary information. This dissertation focuses on the fundamental limits of secure summation under different constraints. We first focus on the minimal model of secure computation, in which two users each hold an input and wish to securely compute a function of their inputs at the server. We propose a novel scheme base on the algebraic structure of finite field and modulo ring of integers. Then we extend the minimal model of secure computation, in which K users wish to securely compute the sum of their inputs at the server. We prove a folklore result on the limits of communication cost and randomness cost. Then we characterized the optimal communication cost with user dropouts constraint, when some users may lose connection to the server and the server wishes to compute the sum of remaining inputs. Next, we characterize the optimal communication and randomness cost for symmetric groupwise keys and find the feasibility condition for arbitrary groupwise keys. Last, we study the secure summation with user selection, such that the server may select any subset of users to compute the sum of their inputs. This leads us to the MDS variable generation problem. We characterize the optimal individual key rate and the result is interestingly the harmonic number.

Channels with state model communication settings where the channel statistics are not fully known or vary over transmissions. It is important for a communication system to obtain the channel state information in terms of increasing channel capacity. This thesis addresses the effect of the quality of state information on channel capacity. Extreme scenarios are studied to reveal the limit in increasing channel capacity with the knowledge of state information. We consider the channel with the perfect state information at the decoder, while the encoder is only available to a noisy state observation. The effect of the noisy state at the encoder to the channel capacity is studied. We show that for any binary-input channel if the mutual information between the noisy state observation at the encoder and the true channel state is below a positive threshold determined solely by the state distribution, then the capacity is the same as that with no encoder side information. A complementary phenomenon is also revealed for the generalized probing capacity. Extensions beyond binary-input channels are developed. We further investigate the channel capacity, when the causal channel state information (available at the encoder or the decoder or both) makes it deterministic. Every such a capacity is called an intrinsic capacity of the channel. Among them, the smallest and the largest called the lower and the upper intrinsic capacities, are particularly studied. Their exact values are determined in most cases when the input or the output is binary. General lower and upper bounds are also provided for the lower and the upper intrinsic capacities with causal state information available at both sides. Byproducts of this work are a generalization of the Birkhoff-von Neumann theorem and a result on the uselessness of causal state information at the encoder. / Thesis / Doctor of Philosophy (PhD) / It is well known that with the knowledge of channel state, it is possible to increase the channel capacity. In this sense, knowing channel state never hurts. However, whether it is always bene cial to actively acquire channel state is another story. If we take into account the cost of measuring the channel state against the potential gain on the capacity, sometimes it may not appear very economic to do so. This thesis studies the effect of the quality of observed channel states on the channel capacity. It has been found out in some circumstances the channel capacity is very sensitive to the noise on the state information. On the other hand, it appears that the maximum capacity can be achieved with the knowledge of a small portion of the total channel state information under a slightly different setting. This thesis proves the generality of such phenomena in binary-input channels and provides the necessary and sufficient conditions for the occurrence of such phenomena for an arbitrary channel. This paper also introduces the idea of intrinsic capacity which can be used to measure the ultimate capacity potential of a channel by exploring the channel state. By viewing an arbitrary channel as a deterministic channel with state, the greatest possible and smallest possible capacities have been either derived or bounded in the thesis.

EU electricity markets are facing fundamental challenges as a result of the EU goal to increase the share of the renewable energy sources. This policy negatively influences profitability of the conventional producers known theoretically as "missing money" problem. As the conventional plants are crucial to offset the variability of renewable, this policy puts the stability of the whole grid at risk in long-term under the current electricity market design. The thesis tests and confirms the hypothesis that there is currently a "missing money" effect on the German energy market through a dynamic programming model. Secondly, three types of the capacity remuneration mechanisms (CRMs) are implemented (capacity payments, strategic reserve and capacity auction) in order to deal with "missing money" which mostly eliminates the missing money problem depending on the setting. The most effective CRM seems be the capacity auction model as the price is set dynamically by the market players and not arbitrarily by central regulator. The thesis further supports the creation of the demand flexibility scheme due to the expected low costs. Powered by TCPDF (www.tcpdf.org)