Bibliografie tematiche / Crossing rates

Letteratura scientifica selezionata sul tema "Crossing rates"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 26 gennaio 2023

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Articoli di riviste sul tema "Crossing rates"

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Kulasekera, K. B. "Crossing points of failure rates". Communications in Statistics - Theory and Methods 28, n. 1 (1999): 87–104. http://dx.doi.org/10.1080/03610929908832284.

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Bagdonavičius, Vilijandas, Rūta Levulienė e Mikhail Nikulin. "Testing absence of hazard rates crossing". Comptes Rendus Mathematique 347, n. 7-8 (aprile 2009): 413–18. http://dx.doi.org/10.1016/j.crma.2009.02.014.

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Reid, Scott M., Scott Stoklosar, Serge Metikosh e Jim Evans. "Effectiveness of Isolated Pipeline Crossing Techniques to Mitigate Sediment Impacts on Brook Trout Streams". Water Quality Research Journal 37, n. 2 (1 maggio 2002): 473–88. http://dx.doi.org/10.2166/wqrj.2002.031.

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Abstract Stream populations of brook trout (Salvelinus fontinalis) are sensitive to sediment-caused changes to habitat, i.e., increased embeddedness of bed material. The use of watercourse crossing techniques (dam and pump, and flume methods) that isolate the construction site by diverting flow around the crossing has often been promoted as a means of controlling the amount of sediment released, particularly for those watercourses with sensitive fish species or habitats. However, few case studies have evaluated the effectiveness of isolated crossing construction techniques to mitigate the effects of instream construction activities. We measured suspended sediment concentrations during six isolated pipeline crossings of brook trout streams in Minnesota, Nova Scotia and Ontario. In addition, sediment deposition rates, riffle habitats and fish abundance were monitored upstream and downstream of four of the crossings. Results of our monitoring studies indicate that isolated techniques can be very effective at: (1) minimizing increases to downstream suspended sediment concentrations during instream construction; and, (2) preventing sediment-induced effects on habitat and fish abundance downstream of pipeline water crossings. For sensitive watercourses, isolated crossing techniques are an effective alternative to trenchless crossing techniques (e.g., horizontal directional drilling).
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Cyr, Justin D., John W. Shaw e Peter T. Savolainen. "Motor Vehicle Crashes Involving Railroad Crossing Signal Masts and Guardrails". Transportation Research Record: Journal of the Transportation Research Board 2673, n. 12 (1 luglio 2019): 191–203. http://dx.doi.org/10.1177/0361198119857952.

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The installation of “active” warning devices, such as crossing signals and gates, is a principal element of state and federal railroad crossing safety programs, and their effectiveness in preventing vehicle–train collision is well documented. While most active crossings are occupied by trains only a few minutes each day, non-crashworthy items are frequently present at active crossings including crossing signal masts, crossing gate mechanisms, cantilever supports, and signal controller bungalows. Various agencies utilize longitudinal guardrail systems to protect errant motorists from striking non-frangible crossing signal hardware. This study sought to determine whether such guardrails influence the prevalence and severity of motor vehicle strikes involving crossing hardware. A review of 10 years of police crash-report narratives in Iowa, United States (U.S.) indicates an average of 15.6 crashes per year at 1,853 crossings involving signal masts, signal guardrails, or related infrastructure. Over this period, one fatality and five serious injuries occurred as a result of these crashes. The crash-injury severity distributions appeared similar in crashes with and without guardrail, and regression models showed that guardrail presence did not affect the rate of crashes involving railroad apparatus. Although the use of longitudinal guardrail systems did not appear to have a strong effect on crash rates or severity at active grade crossings, other methods for reducing crash prevalence and severity could be explored in future research, such as the development of crashworthy signal assemblies for flashing-signal-only crossings and the redesign of gate and cantilever supports to increase separation from the traveled way.
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Ivanis, Predrag, Dusan Drajic e Branka Vucetic. "Level Crossing Rates in Transmit Beamforming Systems". IEEE Communications Letters 11, n. 3 (marzo 2007): 246–48. http://dx.doi.org/10.1109/lcomm.2007.061758.

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Hall, G. "Level crossing rates in binary counting systems". Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 371, n. 3 (marzo 1996): 580–82. http://dx.doi.org/10.1016/0168-9002(95)01436-5.

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Goosem, Miriam. "Effects of tropical rainforest roads on small mammals: inhibition of crossing movements". Wildlife Research 28, n. 4 (2001): 351. http://dx.doi.org/10.1071/wr99093.

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Along a narrow, unsealed road through rainforest in north-eastern Queensland, movements of small mammals were examined to determine whether the road would inhibit road crossings, thereby causing linear barrier effects. Crossings of a 12- or 20-m-wide road clearing by Melomys cervinipes were severely inhibited, crossing inhibition of Rattus sp. was less severe, while crossings by Uromys caudimaculatus were unaffected. This differential effect was attributed to species differences in size, mobility and behaviour. Baiting on only one side of the road increased crossing rates for all species. During the breeding season, crossings of 20-m clearings by Rattus sp. were almost completely inhibited and were significantly fewer than crossings of 12-m clearings. Clearing width had little effect on crossing rate outside the breeding season. Seasonal dispersal of juvenile and breeding animals appeared to explain this discrepancy in clearing-width effects. Rattus sp. were significantly less likely to cross a road where there was no vegetative cover at the entrance to a road culvert than where there was cover at both culvert entrances. Linear barrier effects for small mammals may be mitigated by narrower road-clearing widths, by replanting of grassy road verges resulting in increased cover at culvert entrances and canopy closure above the road, and by providing more faunal underpasses.
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Zhou, Zhuping, Qizhou Hu e Wei Wang. "Modeling Pedestrian’s Conformity Violation Behavior: A Complex Network Based Approach". Computational Intelligence and Neuroscience 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/865750.

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Pedestrian injuries and fatalities present a problem all over the world. Pedestrian conformity violation behaviors, which lead to many pedestrian crashes, are common phenomena at the signalized intersections in China. The concepts and metrics of complex networks are applied to analyze the structural characteristics and evolution rules of pedestrian network about the conformity violation crossings. First, a network of pedestrians crossing the street is established, and the network’s degree distributions are analyzed. Then, by using the basic idea of SI model, a spreading model of pedestrian illegal crossing behavior is proposed. Finally, through simulation analysis, pedestrian’s illegal crossing behavior trends are obtained in different network structures and different spreading rates. Some conclusions are drawn: as the waiting time increases, more pedestrians will join in the violation crossing once a pedestrian crosses on red firstly. And pedestrian’s conformity violation behavior will increase as the spreading rate increases.
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Berezhkovskii, Alexander M., Irina V. Gopich e Attila Szabo. "Diffusive barrier crossing rates from variationally determined eigenvalues". Journal of Chemical Physics 155, n. 3 (21 luglio 2021): 034104. http://dx.doi.org/10.1063/5.0058066.

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Barnett, J. T., e B. Kedem. "Zero-crossing rates of functions of Gaussian processes". IEEE Transactions on Information Theory 37, n. 4 (luglio 1991): 1188–94. http://dx.doi.org/10.1109/18.86972.

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Più fonti

Tesi sul tema "Crossing rates"

1

Hellenthal, Garrett. "Exploring rates and patterns of variability in gene conversion and crossover in the human genome /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8961.

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Kuo, Ping-Heng. "Channel Variations in MIMO Wireless Communication Systems: Eigen-Structure Perspectives". Thesis, University of Canterbury. Electrical and Computer Engineering, 2007. http://hdl.handle.net/10092/1212.

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Many recent research results have concluded that the multiple-input multiple-output (MIMO) wireless communication architecture is a promising approach to achieve high bandwidth efficiencies. MIMO wireless channels can be simply defined as a link for which both the transmitting and receiving ends are equipped with multiple antenna elements. This advanced communication technology has the potential to resolve the bottleneck in traffic capacity for future wireless networks. Applying MIMO techniques to mobile communication systems, the problem of channel fading between the transmitters and receivers, which results in received signal strength fluctuations, is inevitable. The time-varying nature of the mobile channel affects various aspects of receiver design. This thesis provides some analytical methodologies to investigate the variation of MIMO eigenmodes. Although the scope is largely focussed on the temporal variation in this thesis, our results are also extended to frequency variation. Accurate analytical approximations for the level crossing rate (LCR) and average fade duration (AFD) of the MIMO eigenmodes in an independent, identically distributed (i.i.d.) flat-fading channel are derived. Furthermore, since several channel metrics (such as the total power gain, eigenvalue spread, capacity and Demmel condition number) are all related to the eigenmodes, we also derive their LCRs and AFDs using a similar approach. The effectiveness of our method lies in the fact that the eigenvalues and corresponding channel metrics can be well approximated by gamma or Gaussian variables. Our results provide a comprehensive, closed-form analysis for the temporal behavior of MIMO channel metrics that is simple, robust and rapid to compute. An alternative simplified formula for the LCR for MIMO eigenmodes is also presented with applications to different types of autocorrelation functions (ACF). Our analysis has been verified via Monte Carlo computer simulations. The joint probability density function (PDF) for the eigenvalues of a complex Wishart matrix and a perturbed version of it are also derived in this thesis. The latter version can be used to model channel estimation errors and variations over time or frequency. Using this PDF, the probabilities of adaptation error (PAE) due to feedback delay in some adaptive MIMO schemes are evaluated. In particular, finite state Markov chains (FSMC) have been used to model rate-feedback system and dual-mode antenna selection schemes. The PDF is also applied to investigate MIMO systems that merge singular value decomposition (SVD)-based transceiver structure and adaptive modulation. A FSMC is constructed to investigate the modulation state entering rates (MSER), the average stay duration (ASD), and the effects of feedback delay on the accuracy of modulation state selection in mobile radio systems. The system performance of SVD-based transceivers is closely related to the quality of the channel information at both ends of the link. Hence, we examine the effect of feedback time delay, which causes the transmitter to use outdated channel information in time-varying fading channels. In this thesis, we derive an analytical expression for the instantaneous signal to interference plus noise ratio (SINR) of eigenmode transmission with a feedback time delay. Moreover, this expression implies some novel metrics that gauge the system performance sensitivity to time-variations of the steering vectors (eigenvectors of the channel correlation matrix) at the transmitter. Finally, the fluctuation of the channel in the frequency domain is of interest. This is motivated by adaptive orthogonal frequency division multiplexing (OFDM) systems where the signalling parameters per subcarriers are assigned in accordance with some channel quality metrics. A Gaussian distribution has been suggested to approximate the number of subcarriers using certain signalling modes (such as outage/transmission and diversity/multiplexing), as well as the total data rates, per OFDM realization. Additionally, closed-form LCRs for the channel gains (including the individual eigenmode gains) over frequency are also derived for both single-input single-output (SISO) and MIMO-OFDM systems. The corresponding results for the average fade bandwidth (AFB) follow trivially, These results may be useful for system design, for example by calculating the feedback overheads based on subcarrier aggregation.
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Fraidenraich, Gustavo 1975. "Distribuições e estatisticas de ordem superior para o canal sem fio". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260559.

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Orientador: Michel Daoud Yacoub
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Neste trabalho, uma nova distribuição de probabilidade amplamente geral, a distribuição a-?-?-µ, é proposta. Esta distribuição contempla como casos particulares várias outras distribuições conhecidas na literatura, tais como Rayleigh, Rice, Nakagami-m, Hoyt, Weibull, a-? (Gamma Generalizada) ?-µ e ?-µ. Por conta de sua generalidade, todos os mais importantes ambientes de desvanecimento de curto prazo são modelados por esta distribuição. Além de prover a função densidade de probabilidade para o modelo a-?-?-µ, os momentos e a função cumulativa de probabilidade também são encontrados. Este modelo geral é então especializado para quatro casos particulares, para os quais distribuições mais simples, mas ainda gerais, são encontradas: a a-?-µ, a-?-µ, ?-? Simétrica e ?-? Assimétrica. Para esses casos, estimadores práticos baseados nos momentos são deduzidos. A aplicabilidade destes estimadores é verificada utilizando medidas de campo realizadas na Unicamp com um equipamento construído no laboratório Wisstek para este ?m. Em seguida, estatísticas de ordem superior, em particular a taxa de cruzamento de nível e a duração média de desvanecimento, são encontradas de forma exata para os ambientes Hoyt e Weibull em sistemas de diversidade com M ramos desbalanceados, não idênticos e independentes utilizando os combinadores por ganho igual e por razão máxima. Neste trabalho, o resultado geral é validado através de simulações e redução das expressões gerais para casos em que os resultados já são conhecidos. Além disso, para alguns destes casos particulares, as expressões gerais são simplificadas e reduzidas a fórmulas fechadas. Estendendo esse último campo de investigação e seguindo um pioneiro trabalho da literatura, o qual abordou o caso Rayleigh, a taxa de cruzamento de nível e a duração média de desvanecimento são obtidas para ambientes Hoyt com dois ramos correlacionados. Nesta investigação, reformula-se a metodologia da literatura e obtém-se um procedimento geral para a análise da taxa de cruzamento de nível e duração média de desvanecimento em ambientes com apenas um cluster, com aplicação direta aos canais Rice, Weibull, ?-? Simétrica e ?-? Assimétrica. Finalmente, este trabalho propõe, de forma precursora, uma distribuição para a fase do canal Nakagami-m. Ao contrário do que, convencionalmente e por simplicidade, se postulava, a distribuição de fase é não uniforme e dependente de m, o que torna o modelo compatível com aqueles aproximados por Nakagami-m, nomeadamente Hoyt e Rice
Abstract: In this work, a new, very general probability density function, the a-?-?-µ distribution, is proposed. This distribution comprises, as particular cases, several other well known distributions such as Rayleigh, Rice, Nakagami-m, Hoyt, Weibull, a-? (Generalized Gamma) ?-µ and ?-µ. Due to its generality, all of the most important short fading environments can be modeled by this distribution. Besides providing the probability density function for the a-?-?-µ model, the moments and the cumulative distribution function are also found. This general model is then specialized into four particular cases, for which new simpler, though still general, distributions, are found: the a-?-µ, a-?-µ, Symmetrical ?-?, and Asymmetrical ?-?. For these cases, practical moment-based estimators are derived. The applicability of these estimators is verified using field measurements obtained through an experiment conducted at the University of Campinas (Unicamp) with an equipment specially built for this end in the Wisstek laboratory. Higher order statistics, more specifically the level crossing rates and average fade durations, are then obtained in an exact form for the Hoyt and Weibull fading environments. The results are applicable to M unbalanced, non-identical, and independent channels using equal gain and maximal ratio combining techniques. The general results are thoroughly validated by means of simulation and also by reducing the general solution to some particular cases for which the solutions are known. Moreover, new closed form expressions are also achieved for some of these particular cases. Extending this field of investigation and following a pioneering work in the literature, which approached the Rayleigh case, the level crossing rate and average fade duration are obtained considering two correlated, unbalanced, and non-identical branches in a Hoyt fading environment. In this investigation, the methodology found in the literature is reformulated and generalized so as to comprise several other cases. The general procedure developed for this analysis can now be applied to other fading environment for which one cluster of mutipaths exists, i.e., Rice, Weibull, Symmetrical ?-?, and Asymmetrical ?-?. Finally, this work proposes, in a pioneering way, the phase distribution for the Nakagami-m channel. Contrary to what conventionally, and for simplicity, was usually postulated, the phase distribution is non-uniform and dependent on m, rendering this model compatible with those approximated by Nakagami-m, namely Hoyt and Rice
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Azadi, Javad Raymond. "Cationic silver enhances the rate of cyclobutane pyrimidine dimer formation by increasing intersystem crossing". Connect to resource, 2009. http://hdl.handle.net/1811/36997.

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Honors thesis (B.S.)--Ohio State University, 2009.
Title from first page of PDF file. Includes bibliographical references (p. [39]-[40]). Available online via Ohio State University's Knowledge Bank.
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Pimentel, Angela Bairos. "Algorithm for the Parkinson’s disease behavioural models characterization using a biosensor". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8443.

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Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica
The neurodegenerative disease, Parkinson’s Disease (PD) constitutes a major health problem in the modern world, and its impact on public health and society is expected to increase with the ongoing ageing of the human population. This disease is characterized by motor and non-motor manifestations that are progressive and ultimately refractory to therapeutic interventions. The degeneration of dopaminergic neurons emanating from the substantia nigra is largely responsible for the motor manifestations. Thus, understanding the behaviour related to this disease is an added value for the diagnosis and treatment of PD. Also, in vivo models are essential tools for deciphering the molecular mechanisms underpinning the neurodegenerative process. Zebrafish has several features that make this species a good candidate to study PD. In particular, the occurrence of behavioural phenotypes of treated animals with neurotoxin drugs that mimic the disease has been investigated. And, an electric biosensor, Marine On-line Biomonitor System (MOBS) is being used for the real-time quantification of such behaviour. This equipment allows quantifying the fish movements through signal processing algorithms. Specifically, the algorithm is used for the evaluation of fish locomotion detected by a series of bursts in the domain of MOBS that correspond to the zebrafish tail-flip activity. In this thesis we proceeded to the development of an algorithm affording a electrical signal discrimination between "healthy" and "ill" zebrafish and consequently improving the detection of parkinsonism-like phenotypes in zebrafish. The first approach was the improvement of the existent algorithm. However, the first analysis failed to distinguish between different behavioural phenotypes when fish were treated with the neurotoxin 6-hydroxydopamine (6-OHDA). Consequently, we generated a new algorithm based on Machine Learning techniques. As a result, the novel algorithm provided a classification over the health condition of the fish, if the same is "healthy" or "ill" with its respective probability and the level of activity of the fish in number of tail-flips per minute. The method Support Vector Machine (SVM)was useful for the classification of the fish events. The zero crossing rate parameter was used for the characterization of the swimming activities. The algorithm was also integrated in the platform Open Signals, and for a faster evaluation of the signals, the algorithm implementation included parallel programming methods. This algorithm is a useful tool to study behaviour in zebrafish. Not only it will allow a more realistic study over the PD research area but also test and assess new drugs that use zebrafish as animal model.
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Gathy, Maude. "On some damage processes in risk and epidemic theories". Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210063.

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Cette thèse traite de processus de détérioration en théorie du risque et en biomathématique.

En théorie du risque, le processus de détérioration étudié est celui des sinistres supportés par une compagnie d'assurance.

Le premier chapitre examine la distribution de Markov-Polya comme loi possible pour modéliser le nombre de sinistres et établit certains liens avec la famille de lois de Katz/Panjer. Nous construisons la loi de Markov-Polya sur base d'un modèle de survenance des sinistres et nous montrons qu'elle satisfait une récurrence élégante. Celle-ci permet notamment de déduire un algorithme efficace pour la loi composée correspondante. Nous déduisons la famille de Katz/Panjer comme famille limite de la loi de Markov-Polya.

Le second chapitre traite de la famille dite "Lagrangian Katz" qui étend celle de Katz/Panjer. Nous motivons par un problème de premier passage son utilisation comme loi du nombre de sinistres. Nous caractérisons toutes les lois qui en font partie et nous déduisons un algorithme efficace pour la loi composée. Nous examinons également son indice de dispersion ainsi que son comportement asymptotique.

Dans le troisième chapitre, nous étudions la probabilité de ruine sur horizon fini dans un modèle discret avec taux d'intérêt positifs. Nous déterminons un algorithme ainsi que différentes bornes pour cette probabilité. Une borne particulière nous permet de construire deux mesures de risque. Nous examinons également la possibilité de faire appel à de la réassurance proportionelle avec des niveaux de rétention égaux ou différents sur les périodes successives.

Dans le cadre de processus épidémiques, la détérioration étudiée consiste en la propagation d'une maladie de type SIE (susceptible - infecté - éliminé). La manière dont un infecté contamine les susceptibles est décrite par des distributions de survie particulières. Nous en déduisons la distribution du nombre total de personnes infectées à la fin de l'épidémie. Nous examinons en détails les épidémies dites de type Markov-Polya et hypergéométrique. Nous approximons ensuite cette loi par un processus de branchement. Nous étudions également un processus de détérioration similaire en théorie de la fiabilité où le processus de détérioration consiste en la propagation de pannes en cascade dans un système de composantes interconnectées.


Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Gale, Brittany Herrod. "Effects of Predation Environment and Food Availability on Somatic Growth in the Livebearing Fish Brachyrhaphis rhabdophora (Pisces: Poeciliidae)". BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3430.

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Variation in somatic growth rates has interested biologists for decades because of the relationship between growth and other fitness-determining traits (i.e. fecundity, survival, and body size), and the corresponding effect of somatic growth on production of organisms humans use for food. The interaction between genetic variation in growth rates and environmentally induced variation in growth rates shows the pattern of growth across multiple environments (i.e. the reaction norm) that clarifies the history and potential future of evolutionary change in growth rates among populations. Theoretical predictions suggest variation in predator-induced mortality rates can influence mean growth rates and the shape of the reaction norm for growth. The adaptive growth hypothesis predicts that mean growth rates would evolve in response to environmental pressures, such as mortality rates, at different body sizes. Few studies, however, have focused on variation in reaction norms for growth in response to resource availability between high-predation and low-predation environments. We used juvenile Brachyrhaphis rhabdophora from high-predation and low-predation environments to test for variation in mean growth rates and for variation in reaction norms for growth at two levels of food availability in a common-environment experiment, and we compared field somatic growth rates in juveniles from the same two environments (high-predation and low-predation). In the common-environment experiment, mean growth rates did not differ between predation environments, but the interaction between predation environment and food level took the form of a crossing reaction norm for both growth in length and growth in mass. Fish from low-predation environments exhibited no significant variation in growth rate between high and low food amount treatments. In contrast, fish from high-predation environments exhibited wide variation in growth rates between low and high food treatments, with higher food availability resulting in higher growth rates. In the field, individuals in the high-predation environment grow at a faster rate than those in a low-predation environment at the smallest sizes (comparable to sizes in the common-environment experiment). These data provide no evidence for evolved differences in mean growth rates between predation environments. However, fish from high-predation environments exhibited greater plasticity in growth rates in response to resource availability suggesting that increased risk of predation could drive variation in food availability for prey and consequent selection for plasticity.
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Suh, Seong-Youp. "A Propagation Simulator for Land Mobile Satellite Communications". Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36632.

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The performance of a mobile satellite communications link can be determined by the propagation path between a satellite and mobile users. Some of the most important factors are multipath propagation and vegetative shadowing. System designers should have the most reliable information about the statistics of fade duration in order to determine fade margin or to compensate for the fades using modulation and coding scheme.

This report describes a simulator, PROSIM, developed at Virginia Tech for simulating a propagation model in land mobile satellite communications. The simulator is based on a random number generator that generates data sets to compute statistics of the propagation channel. Performance of the simulator was evaluated by comparing statistics from an analytical model and experimental data provided by W. Vogel of Univ. of Texas at Austin and J. Goldhirsh of the Applied Physics Laboratory. New expressions for phasor plot and its mathematical expression for lognormal channel were derived and were simulated. Finally, the advantages of the simulator using random number generator in simulating the propagation model are described.
Master of Science

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Costa, Daniel Benevides da. "Estatisticas de ordem superior para canais de desvanecimento Weibull e Nakagami-m". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261823.

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Orientador: Michel Daoud Yacoub
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-06T06:51:34Z (GMT). No. of bitstreams: 1 Costa_DanielBenevidesda_M.pdf: 1293492 bytes, checksum: 3aa8e540fd57db56b2ee4469c60307be (MD5) Previous issue date: 2006
Resumo: Esta dissertação provê uma análise das estatísticas de ordem superior para canais de desvanecimento WeibuII e Nakagami-m. Considerando canais de desvanecimento WeibulI, devido à ausência de um modelo físico para tais canais, estatísticas conjuntas de duas variáveis WeibuII correlacionadas foram obtidas em forma fechada e em função de parâmetros físicos bem conhecidos. Outra estatística encontrada foi a taxa de cruzamento de nível e a duração média de desvanecimento usando diversidade com dois ramos para canais WeibuII correlacionados, desbalanceados e não-idênticos. Além disso, uma caracterização do comportamento do processo de fase e de sua derivada temporal para sinais WeibuII foi realizada. Analisando canais de desvanecimento Nakagami-m, uma expressão simples e em forma fechada para a taxa de cruzamento de fase generalizada foi obtida. Resultados de simulação completamente validaram a formulação proposta. Além disso, novas estatísticas em forma fechada para a envoltória, para as componentes em fase e em quadratura, para a fase e para suas respectivas derivadas temporais foram obtidas
Abstract: This dissertation provides an analysis of the higher order statistics for WeibuII and Nakagami-m fading channels. Conceming WeibuII fading channels, due to the absence of a fading model related of such channels, joint statistics for two correlated WeibuII variates were obtained in cIosed-form and in terms of welI-known physical parameters. Other statistics found were the levei crossing rate and the average fade duration for unbalanced, non-identical, correlated WeibuII channels operating over two branches of diversity. Furthermore, a characterization of the behaviour of the phase process and its time derivative for WeibuII signals was accomplish. Conceming Nakagami-m fading channeIs, a simple and cIosed-form expression for the generalized phase crossing rate was obtained. Results of simulation thoroughly validated the formulation proposed. Moreover, new cIosed-form statistics for the envelope, for the in-phase and quadrature components, for the phase and its respective time derivative were derived.
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Mousselon, Laure. "Radio Wave Propagation Measurements and Modeling for Land Mobile Satellite Systems". Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/10155.

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The performance of a mobile satellite communications link is conditioned by the characteristics of the propagation path between a satellite and mobile users. The most important propagation effect in land mobile satellite system is roadside attenuation of the signals due to vegetation or urban structures. System designers should have the most reliable information about the statistics of the propagation channel to build reliable systems that can compensate for bad propagation conditions. In 1998, the Virginia Tech Antenna Group developed a simulator, PROSIM, to simulate a propagation channel in the case of roadside tree attenuation in land mobile satellite systems. This thesis describes some improvements to PROSIM, and the adaptation and validation of PROSIM for Digital Audio Radio Satellite systems operating at S-band frequencies. The performance of the simulator for S-band frequencies was evaluated through a measurement campaign conducted with the XM Radio signals at 2.33 GHz in various propagation environments. Finally, additional results on dual satellite systems and fade correlation are described.
Master of Science
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Più fonti

Libri sul tema "Crossing rates"

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Hunt, J. G. Accident rates at pedestrian crossings in Hertfordshire. Crowthorne: Transport and Road Research Laboratory, 1989.

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Hanson, Gordon H. Birth rates and border crossings: Latin American migration to the US, Canada, Spain, and the UK. Cambridge, MA: National Bureau of Economic Research, 2010.

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Hanson, Gordon H. Birth rates and border crossings: Latin American migration to the US, Canada, Spain, and the UK. Cambridge, MA: National Bureau of Economic Research, 2010.

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Guide to railway charges for crossing maintenance and construction. [Montréal]: Canadian Transportation Agency, 2005.

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Guide des frais ferroviaires pour l'entretien et la construction des franchissements. Montréal, Qué: Office des transports du Canada, 2005.

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From The Kalahari to the Clyde: The Journey of an Intrepid Meerkat. USA: Amazon, 2010.

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Capitoli di libri sul tema "Crossing rates"

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Breitung, Karl Wilhelm. "Crossing rates of stochastic processes". In Lecture Notes in Mathematics, 121–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/bfb0073546.

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Sung, Wokyung. "The Mean-First Passage Times and Barrier Crossing Rates". In Graduate Texts in Physics, 313–25. Dordrecht: Springer Netherlands, 2018. http://dx.doi.org/10.1007/978-94-024-1584-1_16.

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Penfold, Thomas J., e Jamie Gibson. "The Role of Vibronic Coupling for Intersystem Crossing and Reverse Intersystem Crossing Rates in TADF Molecules". In Highly Efficient OLEDs, 297–330. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527691722.ch9.

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Punkkinen, M. "Relaxation Rates in Slow-Motion Regime: Application to Methyl Groups Near Level Crossing". In 25th Congress Ampere on Magnetic Resonance and Related Phenomena, 524. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-76072-3_274.

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Orlando, Anthony W. "Crossing the Color Line". In Keeping Races in Their Places, 93–114. New York: Routledge, 2021. http://dx.doi.org/10.1201/b22708-7.

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Jung, P., e B. J. Berne. "The Theory of Multi-Barrier Crossing". In New Trends in Kramers’ Reaction Rate Theory, 67–92. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0465-4_4.

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Baker, Bradley. "Strategic Trade-offs in Hotel Best Rate Guarantees". In Let’s Get Engaged! Crossing the Threshold of Marketing’s Engagement Era, 725–29. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-11815-4_220.

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Dong, Xiaofei, e Norman C. Beaulieu. "Average Level Crossing Rate and Average Fade Duration of Diversity Methods". In Communications, Information and Network Security, 181–203. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4757-3789-9_11.

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Luo, Si-Yang, e Hua Long. "Noise Classification Algorithm Based on Short-Term Energy and Zero-Crossing Rate". In Advances in Intelligent Systems and Computing, 287–92. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1843-7_35.

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Žuraulis, Vidas, e Vidmantas Pumputis. "Vision Zero in Lithuania". In The Vision Zero Handbook, 1–40. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-23176-7_15-1.

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AbstractThis chapter covers statistical data and initiatives related to the challenges and achievements of road safety in Lithuania. After providing an overview and an evaluation of previous programs to improve road safety in Lithuania, we discuss a selection of various improvements and assessment of safe traffic measures and their efficiency through relevant information from research and statistical data analysis. Priorities to achieve safer behavior of road users, safer streets and roads, safer vehicles, safer rail transport, and higher survival rates after accidents are discussed in more detail. The country-specific issues of pedestrian fatalities in dark hours, intensive land transportation due to geographical location, and accidents related to railway level crossings are also presented.
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Atti di convegni sul tema "Crossing rates"

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RUIZ-MONTERO, MARIA J. "From Eyring to Kramers: computation of diffusive barrier crossing rates". In Proceedings of the International School of Physics. WORLD SCIENTIFIC, 1998. http://dx.doi.org/10.1142/9789812839664_0008.

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Dharmawansa, Prathapasinghe, Matthew R. McKay e Peter J. Smith. "Analysis of the Level Crossing Rates for Ordered Random Processes". In ICC 2011 - 2011 IEEE International Conference on Communications. IEEE, 2011. http://dx.doi.org/10.1109/icc.2011.5962952.

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Silveira Santos Filho, Jose Candido, e Michel Daoud Yacoub. "Crossing rates and fade durations of multibranch diversity over correlated Rayleigh channels". In 2006 International Telecommunications Symposium. IEEE, 2006. http://dx.doi.org/10.1109/its.2006.4433406.

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Santos Filho, José Cândido S., Michel D. Yacoub e Gustavo Fraidenraich. "The General Solution for Crossing Rates and Fade Durations of Selection Combining". In XXI Simpósio Brasileiro de Telecomunicações. Sociedade Brasileira de Telecomunicações, 2004. http://dx.doi.org/10.14209/sbrt.2004.240.

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Li, Chuanke, Ian J. Jordaan e Rocky S. Taylor. "Estimation of Local Ice Pressure Using Up-Crossing Rate". In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79396.

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Ice load estimation is required for offshore structures designed for arctic and sub-arctic conditions. This paper focuses on the estimation of local ice pressures. The ‘event-maximum’ method for local ice pressure analysis is based on the maximum pressure of a given event; other local peaks in the data are not included. To study how this may affect local ice pressure estimates, a method based on the up-crossing rate was developed. Field data from 1982 Polar Sea arctic trials in the Beaufort Sea are processed as a time series. Up-crossing rates at different local pressure levels are obtained for local areas of interest. A relationship between up-crossing rate and local pressure-area results is established. Results from the analysis of full-scale data using the event-maximum method are presented in a companion paper. For a sample case, local ice pressure estimates obtained using the up-crossing rate method are compared with those presented in the companion paper, based on analysis using the event-maximum method. The local pressure-area relationship is found to be similar for both the up-crossing rate method and the event-maximum method. Both methods and corresponding analysis results are compared.
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Jensen, Jo̸rgen Juncher. "Simulation of Jack-Up Overturning Using the Monte Carlo Method With Artificially Increased Significant Wave Height". In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20053.

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It is well known from linear analyses in stochastic seaway that the mean out-crossing rate of a level r is given through the reliability index, defined as r divided by the standard deviation. Hence, the reliability index becomes inversely proportional to the significant wave height. For non-linear processes the mean out-crossing rate depends non-linearly on the response level r and a good estimate can be found using the First Order Reliability Method (FORM), see e.g. Jensen and Capul (2006). The FORM analysis also shows that the reliability index is strictly inversely proportional to the significant wave height irrespectively of the non-linearity in the system. However, the FORM analysis only gives an approximation to the mean out-crossing rate. A more exact result can be obtained by Monte Carlo simulations, but the necessary length of the time domain simulations for very low out-crossing rates might be prohibitive long. In such cases the property mentioned above for the FORM reliability index can be assumed valid in the Monte Carlo simulations making it possible to increase the out-crossing rates and thus reduced the necessary length of the time domain simulations by applying a larger significant wave height than relevant from a design point-of-view. The mean out-crossing rate thus obtained can then afterwards be scaled down to the actual significant wave height. Some previous results using this property have been presented by Tonguc and So¨ding (1986), albeit in a more empirical way. In the present paper the usefulness of this property to estimate extreme wave loads will be evaluated considering the overturning of a jack-up rig.
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Annavajjala, Ramesh, e Jinyun Zhang. "Level crossing rates and average outage durations of SINR with multiple co-channel interferers". In MILCOM 2010 - 2010 IEEE Military Communications Conference. IEEE, 2010. http://dx.doi.org/10.1109/milcom.2010.5680111.

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Ivanis, P., D. Drajic e B. Vucetic. "Level Crossing Rates of MIMO-MRC Ricean Channels and Their Implications on Adaptive Systems". In 2007 IEEE International Conference on Communications. IEEE, 2007. http://dx.doi.org/10.1109/icc.2007.127.

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Chau, Yawgeng A., Karl Y. Huang e Yao-Hua Chen. "Level Crossing Rates of Envelop Processes for Multihop Fading Channels with Amplify-and-Forward Relays". In 2007 8th IEEE Wireless Communications and Networking Conference. IEEE, 2007. http://dx.doi.org/10.1109/wcnc.2007.437.

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Guo, H., A. Abdi, A. Song e M. Badiey. "Characterization of delay and Doppler spreads of underwater particle velocity channels using zero crossing rates". In 2010 44th Annual Conference on Information Sciences and Systems (CISS). IEEE, 2010. http://dx.doi.org/10.1109/ciss.2010.5464725.

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Rapporti di organizzazioni sul tema "Crossing rates"

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Nafakh, Abdullah Jalal, Yunchang Zhang, Sarah Hubbard e Jon D. Fricker. Assessment of a Displaced Pedestrian Crossing for Multilane Arterials. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317318.

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This research explores the benefits of a pedestrian crosswalk that is physically displaced from the intersection, using simulation software to estimate the benefits in terms of delay and pedestrian travel time. In many cases, the displaced pedestrian crossing may provide benefits such as reduced vehicle delay, reduced crossing distance, increased opportunity for signal progression, and reduced conflicts with turning vehicles. The concurrent pedestrian service that is traditionally used presents potential conflicts between pedestrians and three vehicular movements: right turns, permissive left turns, and right turns on red. The findings of this research suggest that a displaced pedestrian crossing should be considered as an option by designers when serving pedestrians crossing multi-lane arterials. In addition to reduced delay, pedestrian safety may be improved due to the shorter crossing distance, the elimination of conflicts with turning vehicles, and the potential for high driver compliance rates associated with signals, such as pedestrian hybrid beacons.
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Levy, Avraham, Clifford Weil e Wojtek Pawlowski. Enhancing the Rate of Meiotic Crossing-Over for Plant Breeding. United States Department of Agriculture, gennaio 2009. http://dx.doi.org/10.32747/2009.7696532.bard.

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Meiotic recombination contributes to the generation of biodiversity as well as to genome stability, ensuring the proper segregation of homo logs during meiosis. It is also an essential step in the process of plant breeding. It generates the diversity needed by the breeder for selection of novel varieties. In this project, we have collaborated towards the goals to identify and characterize key genes involved in meiotic recombination. In addition we have shown how some of these genes can be used, through loss of function, or through overexpression, to enhance homologous recombination in Arabidopsis and in maize. Our main achievements can be summarized as follows: 1- To establish a collection of mutants, in Arabidopsis and in maize for candidate genes. In Arabidopsis, insertion mutants were isolated in the following genes: AtMSHI, AtMSH4, AtMSH5, AtMLH3, AtPHSl, and mutants in the Mre11/Rad50/Nbs1 complex. In maize, the TILLING system was established and enabled to isolate mutants in candidate genes, such as Rad2l-4a, Sgo2, and Aml. In addition, we generated phs 1 mutant alleles as well as mutants in the Mre11/Rad50/Nbs1 complex. No mus8l mutants have been found thus far. 2- We showed that mutants in AtMLH3 have decreased rates of crossover, suggesting that overexpression of these genes may enhance crossover. Mutants in AtMSHlhad no effect and mutants in AtMSH4 and 5 showed sterility. Overexpression of these genes might also enhance crossover. The effect of other mutations on crossovers in maize is still being investigated. 3- We showed that overexpression of AtMLH1, RecG and RuvC under a meioticspecific promoter enhances meiotic crossover in Arabidopsis. The effect of PHSloverexpression on crossover is expected to be determined soon. 4- New tools have been developed and perfected to study the recombination genes effect on meiotic crossovers. This includes antibodies, cDNAs and fusion proteins.
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De Donder, Philippe, Marie-Louise Leroux e François Salanié. Advantageous selection without moral hazard. CIRANO, maggio 2022. http://dx.doi.org/10.54932/nqvt3458.

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Advantageous (or propitious) selection occurs when an increase in the premium of an insurance contract induces high-cost agents to quit, thereby reducing the average cost among remaining buyers. Hemenway (1990) and many subsequent contributions motivate its advent by differences in risk-aversion among agents, implying different prevention efforts. We argue that it may also appear in the absence of moral hazard, when agents only differ in riskiness and not in (risk) preferences. We first show that profit-maximization implies that advantageous selection is more likely when markup rates and the elasticity of insurance demand are high. We then move to standard settings satisfying the single-crossing property and show that advantageous selection may occur when several contracts are offered, when agents also face a non-insurable background risk, or when agents face two mutually exclusive risks that are bundled together in a single insurance contract. We exemplify this last case with life care annuities, a product which bundles long-term care insurance and annuities, and we use Canadian survey data to provide an example of a contract facing advantageous selection.
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Gluckstern, R. L., e S. Ohnuma. Estimate of Diffusion Rate Due to Periodic Crossing of Non-Linear Resonance. Office of Scientific and Technical Information (OSTI), agosto 1991. http://dx.doi.org/10.2172/1118937.

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He, Shuyuan, e Benjamin Kedem. Convergence of the Zero-Crossing Rate of Autoregressive Processes and Its Link to Unit Roots. Fort Belvoir, VA: Defense Technical Information Center, gennaio 1988. http://dx.doi.org/10.21236/ada203384.

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Hanson, Gordon, e Craig McIntosh. Birth Rates and Border Crossings: Latin American Migration to the US, Canada, Spain, and the UK. Cambridge, MA: National Bureau of Economic Research, ottobre 2010. http://dx.doi.org/10.3386/w16471.

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Gothilf, Yoav, Roger Cone, Berta Levavi-Sivan e Sheenan Harpaz. Genetic manipulations of MC4R for increased growth and feed efficiency in fish. United States Department of Agriculture, gennaio 2016. http://dx.doi.org/10.32747/2016.7600043.bard.

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The hypothalamic melanocortin system plays a central role in the regulation of food consumption and energy homeostasis in mammals. Accordingly, our working hypothesis in this project was that genetic editing of the mc4r gene, encoding Melanocortin Receptor 4 (MC4R), will enhance food consumption, feed efficiency and growth in fish. To test this hypothesis and to assess the utility of mc4r editing for the enhancement of feed efficiency and growth in fish, the following objectives were set: Test the effect of the mc4r-null allele on feeding behavior, growth, metabolism and survival in zebrafish. Generate mc4r-null alleles in tilapia and examine the consequences for growth and survival, feed efficiency and body composition. Generate and examine the effect of naturally-occurring mc4r alleles found in swordfish on feeding behavior, growth and survival in zebrafish. Define the MC4R-mediated and MC4R-independent effects of AgRP by crossing mc4r- null strains with fish lacking AgRP neurons or the agrpgene. Our results in zebrafish did not support our hypothesis. While knockout of the agrpgene or genetic ablation of hypothalamic AgRP neurons led to reduced food intake in zebrafish larvae, knockout (KO) of the mc4r gene not only did not increase the rate of food intake but even reduced it. Since Melanocortin Receptor 3 (MC3R) has also been proposed to be involved in hypothalamic control of food intake, we also tested the effectofmc3r gene KO. Again, contrary to our hypothesis, the rate of food intake decreased. The next step was to generate a double mutant lucking both functional MC3R and MC4R. Again, the double KO exhibited reduced food intake. Thus, the only manipulation within the melanocortin system that affected food intake in consistent with the expected role of the system was seen in zebrafish larvae upon agrpKO. Interestingly, despite the apparent reduced food intake in the larval stage, these fish grow to be of the same size as wildtype fish at the adult stage. Altogether, it seems that there is a compensatory mechanism that overrides the effect of genetic manipulations of the melanocortin system in zebrafish. Under Aim 3, we introduced the Xna1, XnB1l, and XnB2A mutations from the Xiphophorus MC4R alleles into the zebrafish MC4R gene. We hypothesized that these MC4R mutations would act as dominant negative alleles to increase growth by suppressing endogenous MC4R activity. When we examined the activity of the three mutant alleles, we were unable to document any inhibition of a co-transfected wild type MC4R allele, hence we did not introduce these alleles into zebrafish. Since teleost fish possess two agrpgenes we also tested the effect of KO of the agrp2 gene and ablation of the AgRP2 cells. We found that the AgRP2 system does not affect food consumption but may rather be involved in modulating the stress response. To try to apply genetic editing in farmed fish species we turned to tilapia. Injection of exogenous AgRP in adult tilapia induced significant changes in the expression of pituitary hormones. Genetic editing in tilapia is far more complicated than in zebrafish. Nevertheless, we managed to generate one mutant fish carrying a mutation in mc4r. That individual died before reaching sexual maturity. Thus, our attempt to generate an mc4r-mutant tilapia line was almost successful and indicate out non-obvious capability to generate mutant tilapia.
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