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1
Alkhayuon, Hassan Mazin. "Rate-induced transitions for parameter shift systems". Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/35071.
Testo completoAbstract (sommario):
Rate-induced transitions have recently emerged as an identifiable type of instability of attractors in nonautonomous dynamical systems. In most studies so far, these attractors can be associated with equilibria of an autonomous limiting system, but this is not necessarily the case. For a specific class of systems with a parameter shift between two autonomous systems, we consider how the breakdown of the quasistatic approximation for attractors can lead to rate-induced transitions, where nonautonomous instability can be characterised in terms of a critical rate of the parameter shift. We find a number of new phenomena for non-equilibrium attractors: weak tracking where the pullback attractor of the system limits to a proper subset of the attractor of the future limit system, partial tipping where certain phases of the pullback attractor tip and others track the quasistatic attractor, em invisible tipping where the critical rate of partial tipping is isolated and separates two parameter regions where the system exhibits end-point tracking. For a model parameter shift system with periodic attractors, we characterise thresholds of rate-induced tipping to partial and total tipping. We show these thresholds can be found in terms of certain periodic-to-periodic and periodic-to-equilibrium connections that we determine using Lin's method for an augmented system. Considering weak tracking for a nonautonomous Rossler system, we show that there are infinitely many critical rates at which a pullback attracting solution of the system tracks an embedded unstable periodic orbit of the future chaotic attractor.
2
LeMaster, Cheryl Faye. "Leading Change in Complex Systems: A Paradigm Shift". Antioch University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1500033972019138.
Testo completo
3
Anthony, Romy Leigh. "A stress management module for shift workers". Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/1748.
Testo completoAbstract (sommario):
Thesis (MTech (Human Resources Management))--Cape Peninsula University of Technology, 2006Many people work shifts because of socio-economic considerations and for them stopping shift work is not a realistic option. Shift work can have a negative impact on the health and well being of workers. The reason for this is that in every individual's body there are many rhythms/cycles, which are designed for daytime work. When these rhythms are disrupted as in nightime work, they need time to adjust so that they may all function as one. These rhythms do not adjust instantaneously; therefore the impact on the body is negative. This in turn, leads to a reduction in performance attentiveness, as well as an increase in the risk of accidents and injuries. Most shift workers do not know how to adjust their lifestyle to minimise the negative effects of working around the clock as companies do not provide the required programmes for their well being, thus increasing the chance of suffering from stress. If this is so, then, not only will the well being of the individual or employee be disrupted, but so too will productivity, as well as the profits of the business. This therefore means that shift work could in the end diminish the economic gain it was designed to create. "A tailor-made shift system should be a compromise between the employer's goals, the wishes of employees, and ergonomic recommendations for the design of shift systems" (Knauth, 1997:21). According to Ahasan (2002:09): "Currently there is little information available in the literature that supports the effective design of shift schedules, which offer effective productivity levels, while maintaining the health and safety of shift workers", It therefore has to be realised that there is no ideal shift system, which is going to fully meet an organisations needs, as well as the well being, social and family needs of each and every single employee within the organisation. Employers and employees can work together in order to learn how to identify and control shift work hazards. Also, employees need to learn how to cope better with the demands of their work schedule. Due to the many disruptions encountered in their personal life, social life and physical well being, the existence of stressrelated illnesses is increased in shift workers. Employers may pick up signs of stress when the following factors are monitored on a regular basis, as well as investigated if and when variances occur:
4
Njela, Clive Jonathan. "The impact of shiftwork on productivity". Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1299.
Testo completoAbstract (sommario):
Shiftwork is common in the private sector but not exclusive from the public sector like nursing. In order to secure a continuous operation, and optimization of equipment, businesses introduced shiftwork. The author wanted to test certain hypotheses to better understand the impact of shiftwork. In this research the author first embarked on a theoretical study into shiftwork and its associated problems, which include the impact on productivity, the impact on the employer’s attitude towards the work, the impact on the family life, the impact on social life, the impact on physical health and the psychological effects. Thereafter, an empirical study was conducted to ascertain to what extend shiftwork affects productivity and the life of the employees. The data was then analysed to explain the impact of shiftwork and productivity. Lastly, recommendations were made based on the research.
5
Tang, Xuan. "Polarisation shift keying modulated free-space optical communication systems". Thesis, Northumbria University, 2012. http://nrl.northumbria.ac.uk/8190/.
Testo completo
6
Karstien, Richard F. "Effectively dealing with the problems of shiftwork as a police officer". Instructions for remote access. Click here to access this electronic resource. Access available to Kutztown University faculty, staff, and students only, 2006. http://www.kutztown.edu/library/services/remote_access.asp.
Testo completoAbstract (sommario):
Thesis (M.P.A. )--Kutztown University of Pennsylvania, 2006.Source: Masters Abstracts International, Volume: 45-06, page: 2945. Typescript. Abstract precedes thesis as 2 leaves (iii-iv). Includes bibliographical references (leaves 52-56).
7
Gravely, Marianne Hastoglis. "The effect of shiftwork on dietary intake and personal health perspective of nurses". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09192009-040520/.
Testo completo
8
Zettas, Spiridon. "Adaptive averaging channel estimation for DVB-T2 systems". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16581.
Testo completoAbstract (sommario):
In modern communication systems, the rate of transmitted data is growing rapidly. This leads to the need for more sophisticated methods and techniques of implementation in every block of the transmitter-receiver chain. The weakest link in radio communications is the transmission channel. The signal, which is passed through it, suffers from many degrading factors like noise, attenuation, diffraction, scattering etc. In the receiver side, the modulated signal has to be restored to its initial state in order to extract the useful information. Assuming that the channel acts like a filter with finite impulse, one has to know its coefficients in order to apply the inverse function, which will restore the signal back to its initial state. The techniques which deal with this problem are called channel estimation. Noise is one of the causes that degrade the quality of the received signal. If it could be discarded, then the process of channel estimation would be easier. Transmitting special symbols, called pilots with known amplitude, phase and position to the receiver and assuming that the noise has zero mean, an averaging process could reduce the noise impact to the pilot amplitudes and thus simplify the channel estimation process. In this thesis, a novel channel estimation method based on noise rejection is introduced. The estimator takes into account the time variations of the channel and adapts its buffer size in order to achieve the best performance. Many configurations of the estimator were tested and at the beginning of the research fixed size estimators were tested. The fixed estimator has a very good performance for channels which could be considered as stationary in the time domain, like Additive White Gaussian Noise (AWGN) channels or slowly time-varying channels. AWGN channel is a channel model where the only distorting factor is the noise, where noise is every unwanted signal interfering with the useful signal. The properties of the noise are that it is additive, which means that the noise is superimposed on the transmitted signal, it is white so the power density is constant for all frequencies, and it has a Gaussian distribution in the time domain with zero mean and variance σ2=N. A slowly time varying channel refers to channel with coherence time larger than the transmitted symbol duration. The performance of a fixed size averaging estimator in case of fast time-varying channels is subject to the buffering time. When the buffering time is smaller or equal to a portion of the coherence time the averaging process offers better performance than the conventional estimation, but when the buffering time exceeds this portion of the coherence time the performance of the averaging process degrades fast. So, an extension has been made to the averaging estimator that estimates the Doppler shift and thus the coherence time, where the channel could be assumed as stationary. The improved estimator called Adaptive Averaging Channel Estimator (AACE) is capable to adjust its buffer size and thus to average only successive Orthogonal Frequency Division Multiplexing (OFDM) symbols that have the same channel distortions. The OFDM is a transmission method where instead of transmitting the data stream using only on carrier, the stream is divided into parallel sub-streams where the subcarriers conveying the sub-streams are orthogonal to each other. The use of the OFDM increases the symbol duration making it more robust against Inter-Symbol Interference (ISI), which the interference among successive transmitted symbols, and also divides the channel bandwidth into small sub-bandwidths preventing frequency selectivity because of the multipath nature of the radio channel. Simulations using the Rayleigh channel model were performed and the results clearly demonstrate the benefits of the AACE in the channel estimation process. The performance of the combination of AACE with Least Square estimation (AACE-LS) is superior to the conventional Least Square estimation especially for low Doppler shifts and it is close to the Linear Minimum Mean Square Error (LMMSE) estimation performance. Consequently, if the receiver has low computational resources and/or the channel statistics are unknown, then the AACE-LS estimator is a valid choice for modern radio receivers. Moreover, the proposed adaptive averaging process could be used in any OFDM system based on pilot aided channel estimation. In order to verify the superiority of the AACE algorithm, quantitative results are provided in terms of BER vs SNR. It is demonstrated that AACE-LS is 7dB more sensitive than the LS estimator.
9
Reid, Kathryn J. "Measuring adaption to shiftwork /". Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phr3561.pdf.
Testo completo
10
Croussore, Kevin. "ALL-OPTICAL REGENERATION FOR PHASE-SHIFT KEYED OPTICAL COMMUNICATION SYSTEMS". Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2481.
Testo completoAbstract (sommario):
All-optical signal processing techniques for phase-shift keyed (PSK) systems were developed theoretically and demonstrated experimentally. Nonlinear optical effects in fibers, in particular four-wave mixing (FWM) that occurs via the ultra-fast Kerr nonlinearity, offer a flexible framework within which numerous signal processing functions can be accomplished. This research has focused on the regenerative capabilities of various FWM configurations in the context of processing PSK signals. Phase-preserving amplitude regeneration, phase regeneration, and phase-regenerative wavelength conversion are analyzed and demonstrated experimentally. The single-pump phase-conjugation process was used to regenerate RZ-DPSK pulse amplitudes with different input noise distributions, and the impact on output phase characteristics was studied. Experiments revealed a limited range over which amplitude noise could effectively be suppressed without introduction of phase noise, particularly for signals with intensity pattern effects. Phase regeneration requires use of phase-sensitive amplification (PSA), which occurs in nonlinear interferometers when the pump and signal frequencies are degenerate (NI-PSA), or in fiber directly through single-stage (degenerate) or cascaded (non-degenerate) FWM processes. A PSA based on a Sagnac interferometer provided the first experimental demonstration of DPSK phase and amplitude regeneration. The phase-regenerative capabilities of the NI-PSA are limited in practice by intrinsic noise conversion (amplitude to phase noise) and to a lesser extent by the requirement to modulate the pump wave to suppress stimulated Brillouin scattering (SBS). These limitations are relaxed in novel materials with higher SBS thresholds and nonlinearities. Degenerate FWM provides PSA in a traveling-wave configuration that intrinsically suppresses the noise conversion affecting the NI-PSA, while providing stronger phase-matched gain. Experiments confirmed superior phase-regenerative behavior to the NI-PSA with simultaneous reduction of amplitude noise for NRZ-DPSK signals. Phase-regenerative wavelength conversion (PR-WC) provides the regenerative properties of PSA at a new wavelength, and was proposed and demonstrated for the first time in this research. The parallel implementation of two FWM processes, phase-conjugation and frequency conversion, provides two idlers which exhibit interesting and useful regenerative properties. These were investigated theoretically and experimentally. Ideal phase-regenerative behavior is predicted when the contributing FWM processes are equally phase-matched, which can be maintained over any interaction length or wavelength shift provided the pump powers are properly adjusted. Depleted-pump regime PR-WC provides simultaneous phase and amplitude regeneration. Experiments confirmed regenerative behavior for wavelength shifts of the idlers up to 5 nm. Two techniques for phase regeneration of 4-level PSK signals were developed and evaluated. The first is based on parallel operation of PSAs suitable for processing 2-level PSK signals, where phase projection and regeneration are combined to recover the input data. Analysis of this scheme outlined the conditions required for effective phase regeneration and for practical implementation using known PSAs. A novel process based on FWM (parallel phase-conjugation followed by PSA) was developed and analyzed, and demonstrated using numerical simulations. These studies provide a basis for further work in this area.Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
11
Kerr, Michael P. "Case studies of shift hand-over communication systems in nursing". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312715.
Testo completo
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Buxton, Sandra. "Shift work: An occupational health and safety hazard". Thesis, Buxton, Sandra (2003) Shift work: An occupational health and safety hazard. Masters by Research thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/495/.
Testo completoAbstract (sommario):
Shift work is a major feature of modern work practices. It involves individuals working at times considered unconventional for most workers, such as at night. Although the community often benefits from such work practices, shift work can be hazardous, for both the workers and the community.
The thesis reviews the main problems of shift work, especially when involving night work. These are: an increased risk for accidents and errors; increased sleepiness and fatigue due to difficulties sleeping; increased health problems; and disruption to family and social life. Strategies to limit the risk associated with these hazards are also reviewed, and include using knowledge of circadian principles to plan shift schedules, sleeping schedules and meal times; planned napping; consideration of the work environment; and newer techniques such as using bright lights and melatonin.
While this information is known to the research community, it has not filtered down to many shift work workplaces and thus has had little if any positive effect on actual shift work practices. For a change in shift work practices to occur, the research knowledge must become available to every shift work workplace, as must some incentive or motivation to ensure that workplaces make the necessary changes.
The Occupational Health and Safety (OHS) laws provide such a framework. Considering shift work as an OHS hazard would ensure that all shift work workplaces identified the hazards of shift work, conducted a risk assessment to identify the risk associated with the hazards, and then implemented the appropriate strategies, from the hierarchy of shift work hazard control measures, for both employers and employees, to fulfil their duty of care to minimise the risks. Considering shift work as an OHS issue would ensure that the research information was used as intended - to improve the safety, performance, and quality of life of all shift workers. The present thesis reviews the shift work research and introduces an OHS perspective as a method to manage shift work effectively.
13
Buxton, Sandra. "Shift work : an occupational health and safety hazard /". Access via Murdoch University Digital Theses Project, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040302.154645.
Testo completo
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Chan, Cheuk-ho. "Decomposed network and heuristic approach for rail transport crew scheduling system". Click to view the E-thesis via HKUTO, 1997. http://sunzi.lib.hku.hk/hkuto/record/B4257464X.
Testo completo
15
Oke, Marion. "Nurses, night duty and health : an investigation of night and day nurses' sleep patterns, health status, and family life". Thesis, School of Psychology, 1995. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/164816.
Testo completoAbstract (sommario):
"The primary aim of the study was to compare effects of night work and day work (rotating morning/day/evening shifts) on the physical, psychological and social well being of nurses."Master of Applied Science
16
Johnson, David C. "A shift variant filter applied to edge trace analysis /". Online version of thesis, 1989. http://hdl.handle.net/1850/11357.
Testo completo
17
Wong, Dominic P. C. "Nonredundant error correction of π/4-shift DQPSK systems for mobile and cellular system applications". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30120.
Testo completoAbstract (sommario):
The application of the nonredundant error correction (NEC) technique to the new North American and Japanese Digital Cellular modulation standard, the π/4-shift DQPSK modulation format, is proposed, analyzed and evaluated. Due to the nature of the mobile cellular communication
channel, it is assumed that the π/4-shift DQPSK system is operated in a combined additive white Gaussian noise (AWGN) and cochannel interference (CCI) environment as well as in a frequency-nonselective fading environment.
The NEC techniques can be accommodated to the π/4-shift DQPSK by a modification of the NEC receivers for the DQPSK following which the performance of the NEC receivers with single-, double- and triple-error correction capability are theoretically analyzed and evaluated. The most elaborate system analyzed is the triple-error NEC receiver which employs four differential detectors with delay elements of one up to four symbol duration long and which requires the computation of 12 syndromes for the correction of error symbols.
For the CCI, the general model which includes M statistical independent interferers also employing the π/4-shift DQPSK modulation format is adopted. The theoretical symbol error rate (SER) versus carrier-to-noise (C/N) ratio have been obtained having M and the carrier-to-interference (C/I) ratio as parameters. These performance evaluation results indicate significant performance improvements over conventional differentially detected π/4-shift DQPSK systems without requiring any bandwidth expansion. For example, at a SER = 10ˉ⁴ and for C/I = 14 dB and M = 6, gains of more than 7 dB have been obtained. Compared with a coherent π/4-shift QPSK system operated in the same environment, this triple error correcting NEC is inferior by only 1.5 dB. Some of these theoretical results have also been verified by computer simulation. The gains offered by the NEC receivers have been found to increase as C/I decreases and/or M increases. In addition to the performance improvements, significant error floor reductions (of at least one order of magnitude) have been observed.
For the fading channel, the theoretical error rate equation for the single-error correcting NEC receiver is newly derived. Since numerical evaluation of the derived equation is extremely time consuming, computer simulations were used to obtain the performance evaluation result of π/4-shift DQPSK system employing single- and double-error correcting NEC receivers. In general, the improvement are not as high as that in the CCI environment. For example, at a BER = IOˉ² and for a Rician fading channel with the K-factor of 1 dB with BDT = 6.29, a performance gain of 6 dB is achieved. The gains offered by the NEC receivers increases as the K-factor decreases and/or when the BDT is large.
Since the NEC technique does not require any bandwidth or signal constellation expansion as do other coding schemes, it is a powerful and attractive technique to increase the capacity of digital communication systems operated in CCI controlled (frequency reuse) environment, such as the new all digital North American and Japanese mobile/cellular network. The significant improvement of the NEC receivers in a very fast fading environment suggests the NEC receivers can also be applied to communication applications in which the speed of the mobile unit is very high, for example, in aeronautical communication systems. Finally, it is noteworthy that the results obtained in this thesis for the π/4-shift DQPSK systems are directly applicable to the DQPSK systems in a linear channel.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
18
Basharati, Sarhad. "MIMO and Relay Systems Based on Multi-Amplitude Minimum Shift Keying". Thesis, University of Canterbury. Electrical and Computer Engineering, 2013. http://hdl.handle.net/10092/8491.
Testo completoAbstract (sommario):
This thesis describes the use of a multi-amplitude minimum shift keying (MAMSK) signal in various types of wireless communication system. A MAMSK signal is a bandwidth efficient modulation scheme obtained by superimposing ℳ minimum shift keying (MSK) signals with unequal amplitudes. The overall phase of a MAMSK signal is controlled by the phase of the largest component MSK signal which allows the use of a low-complexity differential detector. A closed form expression for the average bit error rate (BER) for coherent detection of an MAMSK in AWGN is derived and is shown to achieve the same BER as that of square constellation quadrature amplitude modulation (QAM) with the same average transmit power.
We describe the design and implementation of a STBC-based MIMO radio system in conjunction with MAMSK modulation. The proposed system provides high capacity data transmission by carrying information not only in the phases but also in the amplitude. Despite using a simple MAMSK differential receiver the system achieves performance within 1 dB of coherent detection. The existing MSK modems in conjunction with STBC could easily be modified to construct the proposed system.
The MAMSK modulation scheme is extended to a multiuser relaying network where two nodes cooperate in a half-duplex environment to achieve diversity gain. The cooperative scheme is based on superposition modulation using a decode-and-forward (DF) strategy. In the proposed scheme, each node simultaneously transmits its own and the relayed signals by superimposing one on the other. A MAMSK signal is an excellent choice for this type of cooperative communication due its being obtained by a superposition technique. The proposed system exploits the overall phase of a MAMSK signal which allows differential detection and as a result it provides the lowest decoding complexity and memory requirements among the existing superposition based cooperation schemes. The performance of the system is evaluated by simulation, where it is shown that the MAMSK cooperative system outperforms a conventional DF scheme in terms of both power and bandwidth efficiency.
19
Vacondio, Francesco. "On the benefits of phase shift keying to optical telecommunication systems". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27653/27653.pdf.
Testo completoAbstract (sommario):
Les avantages de la modulation de phase vis-à-vis la modulation d’intensité pour les
réseaux optiques sont claires et accepté par la communauté scientifique des télécommunications
optiques. Surtout, la modulation de phase montre une meilleure sensibilité
au bruit, ainsi qu’une plus grande tolérance aux effets non-linéaires que la modulation
d’intensité.
Nous présentons dans cette thése un étude qui vise à développer les avantages de la
modulation de phase. Nous attaquons d’abord la complexité du récepteur en détection
directe, en proposant une nouvelle configuration dont la complexité est comparable à
celle du récepteur pour la modulation d’intensité traditionnel, mais avec des meilleures
performances. Cette solution pourrait convenir pour les réseaux métropolitains (et
même d’accès) à haut débit binaire. Nous passons ensuite à l’examen de la possibilité
d’utiliser des amplificateur à semi-conducteur (SOA) au lieu des amplificateurs à fibre
dopée à l’erbium pour fournir amplification optique aux signaux modulés en phase.
Les non-linéarité des SOA sont étudiées, et un compensateur simple et très efficace est
proposé. Les avantages des amplificateurs à semi-conducteur par rapport à ceux à fibre
sont bien connus. Surtout, la méthode que nous proposons permettrait l’integrabilité
des SOA avec d’autres composants de réseau (par exemple, le récepteur nommé cidessus),
menant à des solutions technologiques de petite taille et efficaces d’un point de
vue énergétique.
Il y a deux types de systèmes pour signaux modulés en phase: basé sur la détection
directe, ou sur les récepteurs cohérents. Dans le dernière partie de ce travail, nous nous
concentrons sur cette dernière catégorie, et nous comparons deux solutions possibles
pour la mise à niveau des réseaux terrestres actuel. Nous comparons deux configurations
dont les performances sont très comparables en termes de sensibilité au bruit, mais nous montrons comment la meilleure tolérance aux effets non linéaires (en particuliers dans
les systèmes à débit mixte) fait que une solution soit bien plus efficace que l’autre.The advantages of phase modulation (PM) vis-à-vis intensity modulation for optical networks are accepted by the optical telecommunication community. PM exhibits a higher noise sensitivity than intensity modulation, and it is more tolerant to the effects of fiber nonlinearity. In this thesis we examine the challenges and the benefits of working with different aspects of phase modulation. Our first contribution tackles the complexity of the direct detection noncoherent receiver for differentially encoded quadrature phase shift keying. We examine a novel configuration whose complexity is comparable to that of traditional receivers for intensity modulation, yet outperforming it. We show that under severe nonlinear impairments, our proposed receiver works almost as well as the conventional receiver, with the advantage of being much less complex. We also show that the proposed receiver is tolerant to chromatic dispersion, and to detuning of the carrier frequency. This solution might be suitable for high-bit rates metro (and even access) networks. Our second contribution deals with the challenges of using semiconductor optical amplifiers (SOAs) instead of typical erbium doped fiber amplifiers (EDFAs) to provide amplification to phase modulated signals. SOAs nonlinearities are investigated, and we propose a simple and very effective feed-forward compensator. Above all, the method we propose would permit the integrability of SOAs with other network components (for example, the aforementioned receiver) achieving small size, power efficient sub-systems. Phase modulation paves the way to high spectral efficiency, especially when paired with digital coherent receivers. With the digital coherent receiver, the degree of freedom offered by polarization can be exploited to increase the channel bit rate without increasing its spectral occupancy. In the last part of this work we focus on polarization multiplexed signaling paired with coherent reception and digital signal processing. Our third contribution provides insight on the strategies for upgrading current terrestrial core networks to high bit rates. This is a particularly challenging scenario, as phase modulation has to coexist with previously installed intensity modulated channels. We compare two configurations which have received much attention in the literature. These solutions show comparable performance in terms of back-to-back noise sensitivity, and yet are not equivalent. We show how the superior tolerance to nonlinear fiber propagation (and particularly to cross phase modulation induced by the presence of intensity modulated channels) makes one of them much more effective than the other.
20
Kalayci, Kubra. "Advanced photochemical systems with bathochromic shift for precision soft materials design". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/236250/1/Kubra%2BKalayci%2BThesis.pdf.
Testo completoAbstract (sommario):
The current thesis introduces novel tools via two photochemically induced ligations; [2+2] photocycloadditions and photouncaging reactions for light-controlled Staudinger-Bertozzi ligations. New chromophores were designed to provide a bathochromic shift for the activation wavelength of both reaction types to address the challenges that prevent these systems to be available for biological applications. In-depth photoreactivity studies using action plots revealed the exact wavelength dependent reactivity of the developed systems along with the effect of solvent and pH on the photoreactivity, which contributed to a fundamental understanding of these reactions. The applicability of these systems was demonstrated by hydrogel fabrication and surface patterning.
21
Brough, Dianne T. "Navigating emotion research during a paradigm shift in psychology". Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/81606/1/Dianne_Brough_Thesis.pdf.
Testo completoAbstract (sommario):
Human emotional responses are highly individual. A comprehensive analysis of emotion research in cognitive psychology and physiology, including laboratory-based experiments, showed that understanding human emotions requires a dynamic systems approach incorporating insights from scientific disciplines beyond psychology. Importantly, subjective and automatic evaluations of emotive information are context-sensitive and changeable, confirming the dynamic nature of emotion and role of individual differences. Furthermore, a comparison of different statistical approaches established that statistical estimation, rather than averages, best captures our highly individual emotional responses. Emotion research needs a cross-disciplinary approach.
22
Rachakonda, Ravi Kanth. "Crew rostering problem a random key genetic algorithm with local search /". Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1230931714.
Testo completo
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Batterson, Andrew. "Effects of a 12 hour shift roster on physiological heat strain: a case study". Thesis, Federation University Australia, 1993. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/164896.
Testo completo
24
Hui, Chi-kwong. "Knowledge-based approach to roster scheduling problems /". [Hong Kong : University of Hong Kong], 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12362840.
Testo completo
25
Pirnot, Joni Burnette. "Recognizable languages defined by two-dimensional shift spaces". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001732.
Testo completo
26
Munton, Lynne Kerry. "The effects of night work and task diversification on efficiency of performance". Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1018253.
Testo completoAbstract (sommario):
This study investigated the effects of night work on performance efficiency. Night work is generally acknowledged to impair performance, yet much research has contradicted this assertion. The feasibility of including brief periods of physical activity to stimulate arousal within mentally demanding work shifts was also evaluated. Thirty six postgraduate volunteers were assigned to either the cognitive tasks (CT) or cognitive and motor tasks (CMT) group. All subjects performed three psycho-motor tests, using the Vienna Test System, at midday and midnight. The CMT group performed a short cycling activity before each test. Heart rate responses served as physiological measures, the Perceived Strain Scale was used to quantify individual perceptions of strain and performance efficiency was assessed in terms of speed and accuracy. Although several trends were apparent, no significant differences (p < 0.05) were revealed with respect to the three performance variables between the midday and midnight test sessions, or between the CT and CMT subjects, other than the higher heart rates recorded in the CMT group. In summary, neither time of day nor physical activity were found to affect performance within the controlled environment of this study.
27
Tambellini, Leonardo [UNESP]. "Sistemas dinâmicos finitos: Paciência Búlgara (Shift em partições e composições cíclicas)". Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/94253.
Testo completoAbstract (sommario):
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tambellini_l_me_sjrp.pdf: 1124234 bytes, checksum: 8cc4df0d667724def74ec4f0b65c3020 (MD5)Neste trabalho abordamos um tema introdutório na interseção de duas áreas da Matemáticas, Sistemas Dinâmicos e Teoria dos Números. Através de um jogo aparentemente ingênuo, a Paciência Búlgara, estudamos dinâmicas em conjuntos finitos. Devidoà finitude do domínio, todos os pontos do sistema convergem para uma órbita periódica, mas interessante é saber quantas órbitas distintas o sistema apresenta em função da quantidade de elementos do domínio. Outra pergunta natural é sobre o tempo de convergência a estas órbitas. Estudamos também uma variação deste jogo, a Paciência Carolina
This work refers to a introductory topic in the intersection of two areas in Mathematics, Dynam-ical Systems and Number Theory. Motivated to a game seemingly naive, Bulgarian Solitaire, we study dynamics in finite sets. Due to the finiteness of the domain,all points of the sys-tem converge to a periodic orbit, but it is interesting to know how many distinct orbits the system displays depending on the size of the domain. Another natural question is about the convergence time of these orbits. We also study a variation of this game, Carolina Solitaire
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Tambellini, Leonardo. "Sistemas dinâmicos finitos : Paciência Búlgara (Shift em partições e composições cíclicas) /". São José do Rio Preto, 2013. http://hdl.handle.net/11449/94253.
Testo completoAbstract (sommario):
Orientador: Vanderlei Minori HoritaBanca: Carlos Gustavo T. de A. Moreira
Banca: Claudio Aguinaldo Buzzi
Resumo: Neste trabalho abordamos um tema introdutório na interseção de duas áreas da Matemáticas, Sistemas Dinâmicos e Teoria dos Números. Através de um jogo aparentemente ingênuo, a Paciência Búlgara, estudamos dinâmicas em conjuntos finitos. Devidoà finitude do domínio, todos os pontos do sistema convergem para uma órbita periódica, mas interessante é saber quantas órbitas distintas o sistema apresenta em função da quantidade de elementos do domínio. Outra pergunta natural é sobre o tempo de convergência a estas órbitas. Estudamos também uma variação deste jogo, a Paciência Carolina
Abstract: This work refers to a introductory topic in the intersection of two areas in Mathematics, Dynam-ical Systems and Number Theory. Motivated to a game seemingly naive, Bulgarian Solitaire, we study dynamics in finite sets. Due to the finiteness of the domain,all points of the sys-tem converge to a periodic orbit, but it is interesting to know how many distinct orbits the system displays depending on the size of the domain. Another natural question is about the convergence time of these orbits. We also study a variation of this game, Carolina Solitaire
Mestre
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Chan, Cheuk-ho, e 陳卓豪. "Decomposed network and heuristic approach for rail transport crew scheduling system". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B4257464X.
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鄭淑慧 e Shuk-wai Sherry Cheng. "Night shift work and risk of breast cancer in women: a literature review". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47560046.
Testo completoAbstract (sommario):
Background
Night shift work is inevitable for maintaining continuous services in different sectors e.g. healthcare, financial, transport and service sectors. Night shift work increases exposure of light at night. Exposure of light at night suppresses production of a neurohormone melatonin. Melatonin has shown potential cancer protective action in animal experiments. Melatonin deficiency is suggested to be related to the development of various cancer especially breast cancer. Breast cancer incidence in Hong Kong is rising. Particular concern about association between night shift work and breast cancer is raised.
Objective
To collect evidence from studies of other countries with study populations of different professions and to evaluate the relationship between night shift work and breast cancer
Method
MEDLINE was searched to identify publications, limited to English articles, from 1973 to May 2011. Search terms include (circadian rhythm or night work or night shift or shift work or work schedule tolerance) and (cancer or neoplasm or neoplasia) and (risk or rate or incidence). No restriction was set to the publication type.
Results
Altogether 343 titles retrieved from MEDLINE search. Finally, 8 primary observational studies that met inclusion criteria were identified for this review. Of these, two were prospective cohort studies, one was retrospective cohort study, two were nested case-control studies and three were case-control studies.
Most of the study had crude exposure assessment of night shift work, in which four studies relied on group level of exposure probability instead of individual exposure information. Six of eight studies showed positive results on the association of night shift work and breast cancer in women. Three studies found that risk of breast cancer was increased significantly for those who had engaged in night shift work in a long duration i.e. more than 20-30 years, but they were all conducted in populations of same occupational group i.e. nurse and only a moderate increase of breast cancer risk was found. The results were subject to confounding and bias. No consistent results were found for effect of shorter duration of night shift work on risk of breast cancer.
Conclusion
Based on the studies included, there is suggestive evidence of an association of night shift work and breast cancer. Further studies on this are needed. Involvement of population of different occupational groups, controlling confounder of hormone use and conducting exposure assessment with high reliability using individual information instead of that from group are suggested.published_or_final_version
Community Medicine
Master
Master of Public Health
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Huysamen, Kirsten Christina. "Validation of an assessment tool for mental fatigue applied to rotational shift work". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013551.
Testo completoAbstract (sommario):
Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
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Barbieri, Lemp Sebastián Andrés. "Shift spaces on groups : computability and dynamics". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN021/document.
Testo completoAbstract (sommario):
Les sous-décalages sont des ensembles de coloriages d'un groupe définis en excluant certains motifs, et munis d'une action de décalage. Ces objets apparaissent naturellement comme discrétisations de systèmes dynamiques : à partir d'une partition de l'espace, on associe à chaque point de ce-dernier la suite des partitions visitées sous l'action du système.Plusieurs résultats récents ont mis en évidence la riche interaction entre la dynamique des sous-décalages et leur propriétés algorithmiques. Un exemple remarquable est la classification des entropies des sous-décalages multidimensionnels de type fini comme l'ensemble des nombres récursivement énumérables à droite. Cette thèse s'intéresse aux sous-décalages avec une approche double : d'un côté on s'intéresse à leurs propriétés dynamiques et de l'autre on les étudie comme des modèles de calcul.Cette thèse contient plusieurs résultats : une condition combinatoire suffisante prouvant qu'un sous-décalage dans un groupe dénombrable est non-vide, un théorème de simulation qui réalise une action effective d'un groupe de type fini comme un facteur d'une sous-action d'un sous-décalage de type fini, une caractérisation de l'effectivité à l'aide de machines de Turing généralisées et l'indécidabilité du problème de torsion pour deux groupes, qui sont invariants de systèmes dynamiques.Comme corollaires de nos résultats, nous obtenons d'abord une preuve courte de l'existence de sous-décalages fortement apériodiques sur tout groupe dénombrable. Puis, dans le cas d'un produit semi-direct de la grille bidimensionnelle avec un groupe de type fini avec problème du mot décidable, nous montrons que le sous-décalage obtenu est de type finiShift spaces are sets of colorings of a group which avoid a set of forbidden patterns and are endowed with a shift action. These spaces appear naturally as discrete versions of dynamical systems: they are obtained by partitioning the phase space and mapping each element into the sequence of partitions visited by its orbit.Severa! breakthroughs in this domain have pointed out the intricate relationship between dynamics of shift spaces and their computability properties. One remarkable example is the classification of the entropies of multidimensional subshifts of finite type as the set of right recursively enumerable numbers. This work explores shift spaces with a dual approach: on the one hand we are interested in their dynamical properties and on the ether hand we studythese abjects as computational models.Four salient results have been obtained as a result of this approach: (1) a combinatorial condition ensuring non-emptiness of subshifts on arbitrary countable groups; (2) a simulation theorem which realizes effective actions of finitely generated groups as factors of a subaction of a subshift of finite type; (3) a characterization of effectiveness with oracles using generalized Turing machines and (4) the undecidability of the torsion problem for two group invariants of shift spaces.As byproducts of these results we obtain a simple proof of the existence of strongly aperiodic subshifts in countable groups. Furthermore, we realize them as subshifts of finite type in the case of a semidirect product of a d-dimensional integer lattice with a finitely generated group with decida ble word problem whenever d> 1
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Kasturi, Prajwal M. "Determination of Ionospheric Current Systems by Measuring the Phase Shift on Amateur Satellite Frequencies". DigitalCommons@USU, 2013. http://digitalcommons.usu.edu/etd/1521.
Testo completoAbstract (sommario):
We investigate the possibility of measuring and using the phase delay of radio frequency transmissions in the amateur satellite band as a method to determine the distribution of currents systems in the ionosphere. The amateur satellite transmissions at 7MHz, 14M Hz, and 144M Hz are low enough for Faraday rotation to cause a significant phase delay on the propagating signals in addition to the phase delay produced by the total electron content (TEC) in the ionosphere. The ionosphere in the E and F regions is modeled as an equivalent thin planar shell of collision free cold plasma 100 km in thickness located in an altitude range of 100 200 km. The earth's magnetic field is superposed with a weaker magnetic field due to a narrow Gaussian strip of current representing an ionospheric electrojet. The prole of the current system is obtained by numerically optimizing the Appleton-Hartree dispersion relation for rays of simulated radio frequency (RF) signals that propagate through the ionosphere shell. The optimization procedure is performed with a differential evolution algorithm. From the optimization procedure, we obtain the ionosphere total electron content (TEC) and the strength, prole, and orientation of the ionospheric current system.
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Forren, Helmut R. "Multiprocessor design methodology for real-time DSP systems represented by shift-invariant flow graphs". Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/15778.
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Rogers, Athena Anne. "Towards the 'Shift-free Integration' of hard and soft systems approaches with an application to the management of non-specialist language learning". Thesis, Liverpool John Moores University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343203.
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Hellner, Joakim. "Introducing quality assessment and efficient management of cellular thermal shift assay mass spectrometry data". Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-311792.
Testo completoAbstract (sommario):
Recent advances in molecular biology has led to the discovery of many new potential drugs. However, difficulties with in situ analysis of ligand binding prevents quick advancement in clinical trials, which stresses the need for better direct methods. A relatively new methodology, called Cellular Thermal Shift Assay (CETSA), allows for detection of ligand binding in a cells natural environment and can be used in combination with Mass Spectrometry (MS) for readout. With help from the Pelago Bioscience team, I developed a pipeline for processing of CETSA MS data and a web based system for viewing the results. The system, called CETSA Analytics, also evaluates the results relevance and helps its users to locate information efficiently. CETSA Analytics is currently being tested by Pelago Bioscience AB as a tool for experimental data distribution.
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Durran, David Michael. "The use of model compounds in a theoretical study of carbohydrate C-13 chemical shift effects". Thesis, University of Surrey, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318658.
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Campbell, Robert F. "Analysis of Various Algorithmic approaches to Software-Based 1200 Baud Audio Frequency Shift Keying Demodulation for APRS". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1634.
Testo completoAbstract (sommario):
Digital communications continues to be a relevant Field of study as new technologies appear and old methodologies get revisited or renovated. The goal of this research is to look into the old digital communication scheme of Bell 202 [67] used by APRS and improve software based demodulation performance. Improved performance is defined by being able to correctly decode more packets in an efficient, real time, manner. Most APRS demodulation is currently done using specialized hardware since that yields the best performance. This research shows that through using Sivan Toledo's javAX25 [72] software package, new demodulation algorithms can be implemented that decode more Bell 202 encoded AX.25 packets than the existing software could. These improvements may help drive the adoption of software demodulation since it is a low cost alternative to specialized hardware.
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Lombard, Wesley Ross. "The effects of booster breaks during a sedentary night shift on physiological, psychomotor, psycho-physiological, and cognitive performance over a 3 night shift habituation phase". Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1005194.
Testo completoAbstract (sommario):
Despite extensive research into shift work, workers working under rotating shift conditions are still plagued by the effects of the desynchronisation resulting from working against their natural circadian rhythms. Additionally, modern industries are shifting towards tasks requiring greater cognitive demand with less manual labour incorporated into the tasks. Research into operator based tasks, and hence those of a sedentary cognitive base both during day and night shifts, has been focusing on the effectiveness of the standard rest/break schedule. Research indicating that the standard rest break schedule is often ineffective in eliminating operator discomfort and performance deterioration, with these affects argued to be more pronounced during a night shift schedule. Therefore current research set out to investigate alternative rest break schedules, incorporating a short bout of physical activity and stretching exercises which are proposed to enhance performance and subjective mood, while eliminating operator discomfort for sedentary based cognitive tasks. Three conditions were tested during a three day habituation shift cycle within a laboratory, incorporating two night shift groups (control and experimental) and a control day shift group. Twelve subjects made up each group, with the two night shift groups completing the shift schedule together. The control groups followed a typical 8 hour shift schedule while the experimental group performed a booster break (exercise and stretches) activity for 7.5 minutes every hour during the night shift schedule. Over the course of the shift, subjects completed a battery of six tests providing data on physiological measurements (heart rate and temperature), performance criteria (reaction time responses, memory and neurobiological) and subjective measures. Responses obtained for all the different parameters measured indicated a strong circadian influence for the majority of the variables, indicating the course of natural down regulation within physiological and performance criteria over the night shift. The booster break significantly improved reaction time performance, subjective ratings and resulted in a high sustainable activity level. Day shift comparisons indicating that within subjective measures and reaction time performance, the booster break resulted in similar responses to those of the day shift workers, while the control night shift groups reported significantly lowers results. Additionally, the booster break had positive influences during the circadian nadir, significantly improving parameters of performance and subjective ratings of sleepiness. The results of this study indicating which variables are strong predictors and indicators of the oscillations in performance and subjective ratings due to the circadian changes. The booster break interventions had positive effects on subjective ratings and reaction time performance, while also being argued to decrease the burden placed on the cardiac system as a result of increased sympathetic tone during the night shift, while additionally resulting in similar responses to those of day shift workers. Further studies are required, however, to provide conclusive evidence particularly within a working situation over a longer shift schedule.
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Pretorius, Riaan Johannes. "An automated IT application for ensuring sustainable savings with load shift systems / Riaan Johannes Pretorius". Thesis, North-West University, 2005. http://hdl.handle.net/10394/130.
Testo completoAbstract (sommario):
In this project, an Information Technology (IT) application was developed that
processes and analyses data that is generated by systems that manage the
electrical power consumption of large energy consumers.
Because of the volume of this data, and the time usually consumed in processing
it manually, (for example, by using Excel spreadsheets) an automated system
was required that does the processing as well as the analysis.
The name "REMS Sentinel" was given to this application. It is divided into two
parts, one of which has already been implemented on a number of gold mines.
The first part processes each day's data from the Energy Management System
(EMS) and then transfers only the most important information to a remote
central database. The processed data can then be viewed on a web page, or on a
cell phone through a specially designed Wireless Application Protocol (WAP)
web site.
The second part of REMS Sentinel then uses the processed data to generate
reports by means of which the previous day's performance of the EMS can be
monitored.
The need for such an automated data processing system has arisen from the
advent of Eskom's Demand Side Management (DSM) program. The purpose of
this is to reduce the energy consumption of large energy users during peak hours
each day.
The Real-time Energy Management System (REMS) was designed to contribute
to the solution of this problem. REMS uses real-time simulation and control
parameters to schedule the consumption of energy during peak hours.
Confidential . .
11
However, REMS generates a large amount of data whilst controlling, for
example, mine equipment in real time. This data is used to calculate the load
that was shifted during peak hours, and to calculate the money that was saved
during each month. Previously, these calculations were carried out manually,
which resulted in huge time delays.
REMS Sentinel solved this problem and enables one operator to monitor several
installations simultaneously.Thesis (M.Ing. (Computer and Electronical Engineering))--North-West University, Potchefstroom Campus, 2006.
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Sugiura, Shinya. "Coherent versus non-coherent space-time shift keying for co-located and distributed MIMO systems". Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/165759/.
Testo completoAbstract (sommario):
In this thesis, we propose the novel Space-Time Coding (STC) concept of Space-Time Shift Keying (STSK) and explore its characteristics in the contexts of both co-located and cooperative Multiple-Input Multiple-Output (MIMO) systems using both coherent and non-coherent detection. Furthermore, we conceive new serially-concatenated turbo-coding assisted STSK arrangements for the sake of approaching the channel capacity limit, which are designed with the aid of EXtrinsic Information Transfer (EXIT) charts. The basic STSK concept is first proposed for the family of co-located MIMO systems employing coherent detection. More specifically, in order to generate space-time codewords, these Coherent STSK (CSTSK) encoding schemes activate one out of Q dispersion matrices. The CSTSK scheme is capable of striking an attractive tradeoff between the achievable diversity gain and the transmission rate, hence having the potential of outperforming other classic MIMO arrangements. Since no inter-channel interference is imposed at the CSTSK receiver, the employment of single-stream-based Maximum Likelihood (ML) detection becomes realistic. Furthermore, for the sake of achieving an infinitesimally low Bit-Error Ratio (BER) at low SNRs, we conceive a three-stage concatenated turbo CSTSK scheme. In order to mitigate the effects of potential Channel State Information (CSI) estimation errors as well as the high pilot overhead, the Differentially-encoded STSK (DSTSK) philosophy is conceived with the aid of the Cayley transform and differential unitary space-time modulation. The DSTSK receiver benefits from low-complexity non-coherent single-streambased ML detection, while retaining the CSTSK scheme’s fundamental benefits. In order to create further flexible STSK architecture, the above-mentioned co-located CSTSK scheme is generalized so that P out of Q dispersion matrices are activated during each space-time block interval. Owing to its highly flexible structure, this generalized STSK scheme subsumes diverse other MIMO arrangements. Finally, the STSK concept is combined with cooperative MIMO techniques, which are capable of attaining the maximum achievable diversity gain by eliminating the undesired performance limitations imposed by uncorrelated fading. More specifically, considering the usual twin-phase cooperative transmission regime constituted by a broadcast phase and by a cooperative phase, the CSTSK and DSTSK schemes developed for co-located MIMO systems are employed during the cooperative transmission phase.
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Purnell, Melissa T., e n/a. "Sleep, alertness, performance and fatigue management in extended duration and irregular night shift workers". University of Otago. Dunedin School of Medicine, 2005. http://adt.otago.ac.nz./public/adt-NZDU20061030.085607.
Testo completoAbstract (sommario):
Extended duration and irregularly planned overnight shifts are becoming frequent features of current working time arrangements. However, there is great concern about the detrimental effect that these shifts are likely to have on the sleep, performance and fatigue levels of workers. To date, the empirical evidence regarding the effects of extended and irregular overnight shifts is sparse and workers have rarely been followed up longer term to assess possible changes over time. Because these types of overnight shifts are being introduced into transport settings such as aviation and shipping where safe and productive operations are paramount, there is a real imperative to examine and trial workplace-based methods aimed at counteracting night shift related fatigue and performance deficits. Taking short duration naps on the nightshift at work is one potential countermeasure that has shown promise in the laboratory but has yet to be examined in any real-world setting under conditions of extended duration or irregular night work. This thesis takes up these issues in a series of four empirical workplace-based studies.
The impact of the introduction of regularly planned 12 h day and overnight shifts was examined on three occasions via questionnaire in a group of aircraft maintenance engineers, once before the change, and twice after the change from 8 h shifts. The results showed that high levels of acute fatigue on the 12 h night shifts and high chronic fatigue levels were common, and were strongly associated with poor overall job performance, poor safety of job performance, and longer recovery times, effects that persisted over time. Of major concern was the finding that over half of the engineers reported having nodded off while driving home from their extended overnight shifts. The impact of irregularly planned 8 h overnight shifts worked by cargo handlers in a shipping container terminal was also examined via self-report questionnaire. The findings revealed significant detrimental impacts on sleep, fatigue levels and performance at work. High fatigue levels were strongly associated with poor self-rated performance output and safety of performance at work on the overnight shifts.
The primary focus of this thesis was to evaluate the effect of a scheduled 20 min nap opportunity taken in these two fully operational workplaces during the night shift on sleep, performance and alertness. Sleep was achieved by 50 to 59% of workers. Speed of performance in 24 male aircraft maintenance engineers on a vigilance task was significantly faster at the end of a 12 h overnight shift that had contained sleep during the nap compared to the control condition. There was no such effect of the nap on the performance of 22 cargo handlers working impromptu 8 h shifts in a shipping container terminal. However, the duration of sleep obtained by the 8 h workers was shorter in comparison and was likely to have been undermined by the high noise levels around the nap facility and time pressures related to the organisation of work. Actigraphy data recorded from all subjects showed that subsequent daytime sleep was not disrupted by the night shift nap opportunity. Overall, the most interesting findings were that simply being tired and presented with a sleep opportunity during the night shift did not guarantee either sleep, or recovery but that sleep, as opposed to rest, was necessary for the benefits to performance to be fully realised.
These findings have shown for the first time that management of fatigue associated with extended duration night work can be achieved in some instances by the use of a short duration nap taken in the workplace on the night shift. However, operationalizing in-situ napping on the night shift has a range of organisational influences that must be considered for the potential of such a strategy to be fully harnessed.
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Raje, Satyajeet. "Data Fusion Ontology:Enabling a Paradigm Shift from Data Warehousing to Crowdsourcing for Accelerated Pace of Research". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1460993523.
Testo completo
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Barter, Trenholm Sharon. "The satisfaction of police officers and their spouses with 12-hour shift work schedules". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq25820.pdf.
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Mitchell, Dana L. Gallagher Thomas Vincent Taylor Steven E. "Extended working hours in the southeastern logging industry". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Forestry_and_Wildlife_Sciences/Dissertation/Mitchell_Dana_20.pdf.
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Pearson, Kristen A. "Circadian rhythms, fatigue, and manpower scheduling". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FPearson.pdf.
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Chen, Dijin, James A. McCorduck e Kamilo Feher. "FQPSK ANALOG/DIGITAL IMPLEMENTATIONS FOR LOW TO ULTRA HIGH DATA RATES IN 1Gb/s RANGE SYSTEMS". International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/606735.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, NevadaFor simpler implementations of ultra high bit rate systems, combined analog/digital techniques, described here in, provide implementations with the smallest number of component count utilizing minimal “real-estate” and smallest DC power. While digital implementations with tradition Read Only Memory (ROM) and Digital to Analog Converters (DAC’s) have been proven in several commercial, NASA -CCSDS recommended, and U.S. DoD-IRIG standardized Feher’s QPSK (FQPSK) [2,3] products, such implementations can be further simplified, and in particular for ultra high bit rate product applications. Several waveform generating techniques such as linear approximation, analog approximation and mixed analog and linear approximations are investigated using preliminary simulation results.
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Feher, Kamilo. "SPECTRAL EFFICIENCY OF COMMERCIAL WIRELESS AND TELEMETRY SYSTEMS IS DOUBLED WITH IRIG 106-00 STANDARDIZED FQPSK AND IS QUADRUPLED WITH FQAM". International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606757.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaAdvances in spectrally efficient Feher’s Quadrature Phase Shift Keying (FQPSK) and Feher‘s Quadrature Amplitude Modulation (FQAM) patented technologies, commercial and government “dual-use” FQPSK products and Test & Evaluation (T&E) results are highlighted in this overview paper. US and international customer requirements/systems, programs and recent deployments and standardization programs are also described. FQPSK doubles the spectral efficiency of PCM/FM Telemetry and of Feher patented Gaussian Minimum Shift Keying (GMSK or FGMSK) and of alternatives, while FQAM quadruples the spectral efficiency of these systems. The predominant focus of this presentation is on an overview and advances of IRIG 106-00 standardized FQPSK technologies. FQAM systems will also be described. Use of FQPSK for applications such as telemetry, data links, clear mode, TDMA ,CSMA and CDMA, OCDMA, WCDMA as well as OFDM – COFDM will be included in the presentation.
49
許志光 e Chi-kwong Hui. "Knowledge-based approach to roster scheduling problems". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B30408982.
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Sopow, Catherine Ruby. "Negotiated Meanings on the Landscape: Culture, Perseverance and a Shift in Paradigms in Klawock, Alaska". Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1538653/.
Testo completoAbstract (sommario):
The purpose of this study is to gain an understanding of Klawock's Tribal Citizens' relationship to harvesting what is colloquially known as customary and traditional foods and/or native foods. The state and federal governments categorize these culturally specific goods as subsistence foods. An unearthed, 5,360-year-old basket potentially links modern day Klawock Tribal Citizens with their ancestral ties to the region. Throughout this time, families in this region of Southeast Alaska have been participating in a form of indigenous fishery. Despite access to multiple grocery stores and fish canneries, tribal citizens choose to expend their family's efforts to harvest their own sockeye out of the Klawock watershed. Oral history and ethnography and methodologies were employed to record personal relationships with the harvest of these resources while also documenting a context in which these relationships exist.
Klawock Cooperative Association's staff worked alongside the student researcher and participants to analyze the data and produce findings. Engaging in customary and traditional activities rewards participants with intrinsic facets of their identity. Alongside reinforcing identities, these activities teach participants about family dynamics and working as a team, as well as the responsibilities that come with. These responsibilities are formed through the assignment of roles and provide people with purpose. The roles of individuals within their family dynamic parallel their understanding of their place within the larger society. Having a purpose and knowing their place shapes participant's accomplishments in the food system and honors them with feelings of pride. Based on these findings, KCA interprets customary and traditional activities as an epistemology in which increased access and participation provides an upwards trajectory of community health.