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1
Klein, Jim, Dan Kulp, and Bob Rashkin. "State Modeling and Pass Automation in Spacecraft Control." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/611435.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe Integrated Monitoring and Control COTS System (IMACCS) was developed as a proof-of-concept to show that commercial off-the-shelf (COTS) products could be integrated to provide spacecraft ground support faster and cheaper than current practices. A key component of IMACCS is the Altair Mission Control System (AMCS), one of several commercial packages available for satellite command and control. It is distinguished from otherwise similar tools by its implementation of Finite State Modeling as part of its expert system capability. Using the Finite State Modeling and State Transition capabilities of the ALTAIR Mission Control System (AMCS), IMACCS was enhanced to provide automated monitoring, routine pass support, anomaly resolution, and emergency "lights on again" response. Orbit determination and production of typical flight dynamics products, such as acquisition times and vectors, have also been automated.
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Hassanzadeh, Mohammadtaghi. "A New State Transition Model for Forecasting-Aided State Estimation for the Grid of the Future." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64407.
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The grid of the future will be more decentralized due to the significant increase in distributed generation, and microgrids. In addition, due to the proliferation of large-scale intermittent wind power, the randomness in power system state will increase to unprecedented levels. This dissertation proposes a new state transition model for power system forecasting-aided state estimation, which aims at capturing the increasing stochastic nature in the states of the grid of the future. The proposed state forecasting model is based on time-series modeling of filtered system states and it takes spatial correlation among the states into account. Once the states with high spatial correlation are identified, the time-series models are developed to capture the dependency of voltages and angles in time and among each other. The temporal correlation in power system states (i.e. voltage angles and magnitudes) is modeled by using autoregression, while the spatial correlation among the system states (i.e. voltage angles) is modeled using vector autoregression. Simulation results show significant improvement in power system state forecasting accuracy especially in presence of distributed generation and microgrids.Ph. D.
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Johanson, Jamin K. "An Evaluation of State-and-Transition Model Development fo Ecological Sites in Northern Utah." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/920.
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Ecological sites and state-transition models (STMs) have become the preferred means of summarizing plant community dynamics on distinctive types of rangeland. Ecological sites classify rangeland types based on soil-geomorphic and climatic conditions capable of producing a known plant community, while a STM depicts the vegetation dynamics of an ecological site. STMs are usually based on expert opinion rather than site-specific data; however, if they are to gain credibility, STMs must accurately describe the processes that drive plant community dynamics. This study examined three ways of developing process-based STMs using three levels of commonly collected field data. We began by taking field inventories of three ecological sites already mapped in northwestern Utah: Loamy Bottom, Mountain Gravelly Loam, and Upland Loam. The Loamy Bottom site was ideal for developing a data-rich, process-based STM because 1) the site concepts were well-defined, 2) the site was easy to recognize, 3) potential states and transitions had already been hypothesized, and 4) the site was easily accessible. The Loamy Bottom study was designed to link plant community structural indicators to measurable indicators of ecological process. Principal components analysis and cluster analysis were used to classify 14 study plots into four distinct states. Simple linear regression showed relationships between perennial grass cover, perennial canopy gaps, and soil organic carbon. Analysis of variance (ANOVA) linked four general vegetation classes to soil stability measurements. The resulting STM describes the structure and function of four alternative states. The other two STMs, developed for the Mountain Gravelly Loam and Upland Loam ecological sites, used less-intensive data collection methods. Rangeland health assessments, used for the Upland Loam STM, are useful for refining initial ecological site and STM concepts, documenting states, hypothesizing transitions, and locating study locations for future research. Quantitative production and cover estimates, used for the Mountain Gravelly Loam STM, are useful for describing the structure of states, but structural indicators must be coupled with process measurements, as with the Loamy Bottom STM to understand the drivers of state change. A coordinated data collection effort is needed to produce STMs that accurately depict the plant community dynamics of ecological sites.
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Kim, Jung Eun. "Analysis of Sleep-Wake Transition Dynamics by Stochastic Mean Field Model and Metastable State." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406206931.
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Takahashi, Daisuke. "Theoretical investigation of the eco-evolutionary dynamics of food webs." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/189654.
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Göransson, (Asker) Christian. "First-Principles calculations of Core-Level shifts in random metallic alloys: The Transition State Approach." Thesis, Linköping University, Department of Physics, Chemistry and Biology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2581.
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The overall aim of this thesis is to compare different methods for calculation of Core-Level shifts in metallic alloys. The methods compared are the Initial State model, the Complete screening and the Transition state model. Core-level shifts can give information of chemical bonding and about the electronic structure in solids.
The basic theory used is the so-called Density-Functional-Theory, in conjunction with the Local-Density Approximation and the Coherent-Potential- Approximation. The metallic alloys used are Silver-Palladium, Copper-Palladium, Copper-Gold and Copper-Platinum, all inface-centered-cubic configuration.
The complete screening- and the transition-state model are found to be in better agreement with experimental results than those calculated with the initial state model. This is mainly due to the fact that the two former models includes final-state effects, whereas the last one do not. The screening parameters within the Coherent-Potential approximation are also investigated. It is found that the Screened-Impurity Model can extend the validity of the Coherent-Potential-Approximation and increase it's accuracy.
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Krometis, Justin. "Lane Preference in a Simple Traffic Model." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/42365.
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We examine the effect of lane preference on a quasi one-dimensional three-state driven lattice gas, consisting of holes and positive and negative particles, and periodic boundary conditions in the longitudinal direction. Particles move via particle-hole and, with a lesser rate, particle-particle exchanges; the species are driven in opposite directions along the lattice, each preferring one of the lanes with a given probability, p. The model can be interpreted as traffic flow on a two-lane beltway, with fast cars preferring the left lane and slow cars preferring the right, viewed in a comoving frame. In steady-sate, the system typically exhibits a macroscopic cluster containing a majority of the particles. At very high values of p, a first order transition takes the system to a spatially disordered state. Using Monte Carlo simulations to analyze the system, we find that the size of the cluster increases with lane preference. We also observe a region of negative response, where increasing the lane preference decreases the number of particles in their favored lane, against all expectations. In addition, simulations show an intriguing sequence of density profiles for the two species. We apply mean-field theory, continuity equations, and symmetries to derive relationships between observables to make a number of predictions verified by the Monte Carlo data.Master of Science
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Xu, Liou. "A MARKOV TRANSITION MODEL TO DEMENTIA WITH DEATH AS A COMPETING EVENT." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/42.
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The research on multi-state Markov transition model is motivated by the nature of the longitudinal data from the Nun Study (Snowdon, 1997), and similar information on the BRAiNS cohort (Salazar, 2004). Our goal is to develop a flexible methodology for handling the categorical longitudinal responses and competing risks time-to-event that characterizes the features of the data for research on dementia. To do so, we treat the survival from death as a continuous variable rather than defining death as a competing absorbing state to dementia. We assume that within each subject the survival component and the Markov process are linked by a shared latent random effect, and moreover, these two pieces are conditionally independent given the random effect and their corresponding predictor variables. The problem of the dependence among observations made on the same subject (repeated measurements) is addressed by assuming a first order Markovian dependence structure.
A closed-form expression for the individual and thus overall conditional marginal likelihood function is derived, which we can evaluate numerically to produce the maximum likelihood estimates for the unknown parameters. This method can be implemented using standard statistical software such as SAS Proc Nlmixed©. We present the results of simulation studies designed to show how the model’s ability to accurately estimate the parameters can be affected by the distributional form of the survival term.
Then we focus on addressing the problem by accommodating the residual life time of the subject’s confounding in the nonhomogeneous chain. The convergence status of the chain is examined and the formulation of the absorption statistics is derived. We propose using the Delta method to estimate the variance terms for construction of confidence intervals. The results are illustrated with applications to the Nun Study data in details.
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Orguner, Umut. "Improved State Estimation For Jump Markov Linear Systems." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607895/index.pdf.
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This thesis presents a comprehensive example
framework on how current multiple model state estimation algorithms for jump Markov linear systems can be improved. The possible improvements are categorized as:
-Design of multiple model state estimation algorithms using
new criteria.
-Improvements obtained using existing multiple model state
estimation algorithms.
In the first category, risk-sensitive estimation is proposed for
jump Markov linear systems. Two types of cost functions namely, the instantaneous and cumulative cost functions related with risk-sensitive estimation are examined and for each one, the
corresponding multiple model estate estimation algorithm is derived.
For the cumulative cost function, the derivation involves the
reference probability method where one defines and uses a new
probability measure under which the involved processes has
independence properties. The performance of the proposed
risk-sensitive filters are illustrated and compared with
conventional algorithms using simulations.
The thesis addresses the second category of improvements by
proposing
-Two new online transition probability estimation schemes for
jump Markov linear systems.
-A mixed multiple model state estimation scheme which combines
desirable properties of two different multiple model state
estimation methods.
The two online transition probability estimators proposed use the
recursive Kullback-Leibler (RKL) procedure and the maximum
likelihood (ML) criteria to derive the corresponding identification
schemes. When used in state estimation, these methods result in an average error decrease in the root mean square (RMS) state
estimation errors, which is proved using simulation studies.
The mixed multiple model estimation procedure
which utilizes the analysis of the single Gaussian approximation of Gaussian mixtures in Bayesian filtering, combines IMM (Interacting Multiple Model) filter and GPB2 (2nd Order Generalized Pseudo Bayesian) filter efficiently. The resulting algorithm reaches the performance of GPB2 with less Kalman filters.
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Van, Dyke Christopher. "Changing States: Using State-and-Transition Models to Evaluate Channel Evolution Following Dam Removal Along the Clark Fork River, Montana." UKnowledge, 2015. http://uknowledge.uky.edu/geography_etds/31.
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Located just east of Missoula, Montana, Milltown Dam stood from 1908 to 2008 immediately downstream of the Clark Fork River’s confluence with the Blackfoot River. After the discovery of arsenic-contaminated groundwater in the nearby community of Milltown, as well as extensive deposits of contaminated sediment in the dam’s upstream reservoir, in 1981, the area was designated a Superfund site – along with much of the Upper Clark Fork Watershed. This motivated the eventual decision to remove the dam, perform environmental remediation, and reconstruct approximately five kilometers of the Clark Fork River and its floodplain. This study is part conceptual and part empirical. It describes a state-and-transition framework equipped to investigate channel evolution as well as the adjustment trajectories of other socio-biophysical landscapes. This framework is then applied to understand the post-restoration channel evolution of the Clark Fork River’s mainstem, secondary channels, and floodplain. Adopting a state-and-transition framework to conceptualize landscape evolution lets environmental managers more effectively anticipate river response under multiple disturbence scenarios and therefore use more improvisational and adaptive management techniques that do not attempt to guide the landscape toward a single and permanent end state. State-and-transition models can also be used to highlight the spatially explicit patterns of complex biophysical response. The state-and-transition models developed for the Clark Fork River demonstrate the possibility of multiple evolutionary trajectories. Neither the secondary channels nor the main channel have responded in a linear, monotonic fashion, and future responses will be contingent upon hydrogeomorphic and climatic variability and chance disturbances. The biogeomorphic adjustments observed so far suggest divergent evolutionary trajectories and that in some instances the long-term fates of the mainstem, floodplain, and secondary channels are inescapably enmeshed with one another.
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Xie, Yan. "STOCHASTIC DYNAMICS OF GENE TRANSCRIPTION." UKnowledge, 2011. http://uknowledge.uky.edu/statistics_etds/2.
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Gene transcription in individual living cells is inevitably a stochastic and dynamic process. Little is known about how cells and organisms learn to balance the fidelity of transcriptional control and the stochasticity of transcription dynamics. In an effort to elucidate the contribution of environmental signals to this intricate balance, a Three State Model was recently proposed, and the transcription system was assumed to transit among three different functional states randomly.
In this work, we employ this model to demonstrate how the stochastic dynamics of gene transcription can be characterized by the three transition parameters. We compute the probability distribution of a zero transcript event and its conjugate, the distribution of the time durations in gene on or gene off periods, the transition frequency between system states, and the transcriptional bursting frequency. We also exemplify the mathematical results by the experimental data on prokaryotic and eukaryotic transcription.
The analysis reveals that no promoters will be definitely turned on to transcribe within a finite time period, no matter how strong the induction signals are applied, and how abundant the activators are available. Although stronger extrinsic signals could enhance promoter activation rate, the promoter creates an intrinsic ceiling that no signals could cross over in a finite time. Consequently, among a large population of isogenic cells, only a portion of the cells, but not the whole population, could be induced by environmental signals to express a particular gene within a finite time period. We prove that the gene on duration follows an exponential distribution, and the gene off intervals show a local maximum that is best described by assuming two sequential exponential process. The transition frequencies are determined by a system of stochastic differential equations, or equivalently, an iterative scheme of integral operators. We prove that for each positive integer n , there associates a unique time, called the peak instant, at which the nth transcript synthesis cycle since time zero proceeds most likely. These moments constitute a time series preserving the nature order of n.
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Zhang, Wenkui. "The emergence of China’s mixed ownership enterprises and their corporate governance." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5920.
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Over the last three decades of the Chinese economic reform with a focus on the state-owned enterprises (SOEs) restructuring, one striking phenomenon is the rise of the mixed ownership enterprises (MOEs) in China. The objective of this thesis is to analyse the factors that can explain the emergence and the rise of the MOEs, to explore the corporate governance of the MOEs, and to assess the performance of the MOEs. The research finds that the unique experiments and practices of China’s SOEs reform in the past 30 years have formed the China Model of SOEs reform, China’s mixed ownership has its roots in the China Model. One major explanation to the rise of the MOEs is the synergy effect gained from the combination of the different advantages of both the private enterprises and the state enterprises. The private enterprises have better operational mechanisms and the state enterprises have better access to business resources and political support. The thesis has looked at 5 issues of the institutional arrangements of MOE’s corporate governance, named as the SCORE. It is found that the largest shareholder in most of the MOEs is still the state, but the control structure is not always corresponding to the shareholding structure, and the governmental intervention in the business of the MOEs has been reduced although the reduction is limited. The thesis shows that there is no noted relationship between corporate performance and mixed ownership, but the transfer of corporate controlling powers is very important for the ownership-transformed companies from whole ownership to mixed ownership to improve the performance. On this basis, the thesis argues that China needs to push forward the further commercialization of the corporate governance of the MOEs in the future
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Chakrabarti, Dwaipayan. "Slow Dynamics In Soft Condensed Matter : From Supercooled Liquids To Thermotropic Liquid Crystals." Thesis, Indian Institute of Science, 2006. http://hdl.handle.net/2005/292.
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This thesis, which contains fourteen chapters in two parts, presents theoretical and computer simulation studies of dynamics in supercooled liquids and thermotropic liquid crystals. These two apparently diverse physical systems are unified by a startling similarity in their complex slow dynamics. Part I consists of six chapters on supercooled liquids while Part II comprises seven chapters on thermotropic liquid crystals. The fourteenth chapter provides a concluding note.
Part I starts with an introduction to supercooled liquids given in chapter 1. This chapter discusses basic features of supercooled liquids and the glass transition and portrays some of the theoretical frameworks and formalisms that are widely recognized to have contributed to our present understanding.
Chapter 2 introduces a new model of binary mixture in order to study dynamics across the supercooled regime. The system consists of an equimolar mixture of the Lennard-Jones spheres and the Gay-Berne ellipsoids of revolution, and thus one of its components has orientational degrees of freedom (ODOF). A decoupling between trans-lational diffusion and rotational diffusion is found to occur below a temperature where the second rank orientational correlation time starts showing a steady deviation from the Arrhenius temperature behavior. At low temperatures, the optical Kerr effect (OKE) signal derived from the system shows a short-to-intermediate time power law decay with a very weak dependence on temperature, if at all, of the power law exponent as has been observed experimentally. At the lowest temperature investigated, jump motion is found to occur in both the translational and orientational degrees of freedom.
Chapter 3 studies how the binary mixture, introduced in the previous chapter, explores its underlying potential energy landscape. The study reveals correlations between the decoupling phenomena, observed almost universally in supercooled molecular liquids, and the manner of exploration of the energy landscape of the system. A significant deviation from the Debye model of rotational diffusion in the dynamics of ODOF is found to begin at a temperature at which the average inherent structure energy of the system starts falling as the temperature decreases. Further, the coupling between rotational diffusion and translational diffusion breaks down at a still lower temperature, where a change occurs in the temperature dependence of the average inherent structure energy.
Chapters 4-6 describe analytical and numerical approaches to solve kinetic models of glassy dynamics for various observables. The β process is modeled as a thermally activated event in a two-level system and the a process is described as a β relaxation mediated cooperative transition in a double-well. The model resembles a landscape picture, conceived by Stillinger [Science 267, 1935 (1995)], where the a process is assumed to involve a concerted series of the β processes, the latter being identified as elementary relaxations involving transitions between contiguous basins. For suitable choice of parameter values, the model could reproduce many of the experimentally observed features of anomalous heat capacity behavior during a temperature cycle through the glass transition as described in chapter 4. The overshoot of the heat capacity during the heating scan that marks the glass transition is found to be caused by a delayed energy relaxation. Chapter 5 shows that the model can also predict a frequency dependent heat capacity that reflects the two-step relaxation behavior. The high-frequency peak in the heat capacity spectra appears with considerably larger amplitude than the low-frequency peak, the latter being due to the a relaxation. The model, when simplified with a modified description of the a process that involves an irreversible escape from a metabasin, can be solved analytically for the relaxation time. This version of the model captures salient features of the structural relaxation in glassy systems as described in chapter 6.
In Part II, thermotropic liquid crystals are studied in molecular dynamics simulations using primarily the family of the Gay-Berne model systems. To start with, chapter 7 provides a brief introduction to thermotropic liquid crystals, especially from the perspective of the issues discussed in the following chapters. This chapter ends up with a detail description of the family of the Gay-Berne models.
Chapter 8 demonstrates that a model system for calamitic liquid crystal (comprising rod-like molecules) could capture the short-to-intermediate time power law decay in the OKE signal near the isotropic-nematic (I-N) phase transition as observed experimentally. The single-particle second rank orientational time correlation function (OTCF) for the model liquid crystalline system is also found to sustain a power law decay regime in the isotropic phase near the I-N transition. On transit across the I-N phase boundary, two power law decay regimes, separated by a plateau, emerge giving rise to a step-like feature in the single-particle second rank OTCF. When the time evolution of the rotational non-Gaussian parameter is monitored as a diagnostic of spatially heterogeneous dynamics, a dominant peak is found to appear following a shoulder at short times, signaling the growth of pseudonematic domains. These observations are compared with those relevant ones obtained for the supercooled binary mixture, as discussed in chapter 2, in the spirit of the analogy suggested recently by Fayer and coworkers [J. Chem. Phys. 118, 9303 (2003)].
In chapter 9, orientational dynamics across the I-N transition are investigated in a variety of model systems of thermotropic liquid crystals. A model discotic system that consists of disc-like molecules as well as a lattice system have been considered in the quest of a universal short-to-intermediate time power law decay in orientational relaxation, if any. A surprisingly general power law decay at short to intermediate times in orientational relaxation is observed in all these systems. While the power law decay of the OKE signal has been recently observed experimentally in calamitic systems near the I-N phase boundary and in the nematic phase by Fayer and coworkers [J. Chem. Phys. 116, 6339 (2002), J. Phys. Chem. B 109, 6514 (2005)], the prediction for the discotic system can be tested in experiments.
Chapter 10 presents the energy landscape view of phase transitions and slow dynamics in thermotropic liquid crystals by determining the inherent structures of a family of one-component Gay-Berne model systems. This study throws light on the interplay between the orientational order and the translational order in the mesophases the systems exhibit. The onset of the growth of the orientational order in the parent phase is found to induce a translational order, resulting in a smectic-like layer in the underlying inherent structures. The inherent structures, surprisingly, never seem to sustain orientational order alone if the parent nematic phase is sandwiched between the high-temperature isotropic phase and the low-temperature smectic phase. The Arrhenius temperature dependence of the orientational relaxation time breaks down near the I-N transition and this breakdown is found to occur at a temperature below which the system explores increasingly deeper potential energy minima. There exists a remarkable similarity in the manner of exploration of the potential energy landscape between the Gay-Berne systems studied here and the well known Kob-Andersen binary mixture reported previously [Nature, 393, 554 (1998)].
In search of a dynamical signature of the coupling between orientational order and translational order, anisotropic translational diffusion in the nematic phase has been investigated in the Gay-Berne model systems as described in chapter 11. The translational diffusion coefficient parallel to the director D// is found to first increase and then decrease as the temperature drops through the nematic phase. This reversal occurs where the smectic order parameter of the underlying inherent structures becomes significant for the first time. The non-monotonic temperature behavior of D// can thus be viewed from an energy landscape analysis as a dynamical signature of the coupling between orientational and translational order at the microscopic level. Such a view is likely to form the foundation of a theoretical framework to explain the anisotropic translation diffusion.
Chapter 12 investigates the validity of the Debye model of rotational diffusion near the I-N phase boundary with a molecular dynamics simulation study of a Gay-Berne model system for calamitic liquid crystals. The Debye model is found to break down near the I-N phase transition. The breakdown, unlike the one observed in supercooled molecular liquids where a jump diffusion model is often invoked, is attributed to the growth of orientational pair correlation. A mode-coupling theory analysis is provided in support of the explanation.
Chapter 13 presents a molecular dynamics study of a binary mixture of prolate ellipsoids of revolution with different aspect ratios interacting with each other through a generalized Gay-Berne potential. Such a study allows to investigate directly the aspect ratio dependence of the dynamical behavior.
In the concluding note, chapter 14 starts with a brief summary of the outcome of the thesis and ends up with suggestion of a few relevant problems that may prove worthwhile to be addressed in future.
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Flaig, Maja [Verfasser], Michael [Akademischer Betreuer] Schneider, and Jan [Akademischer Betreuer] Hofer. "The Contributions of Knowledge and Stress to Academic Achievement: A Meta-Analysis, a Latent Transition Analysis, and a Latent State-Trait Model / Maja Flaig ; Michael Schneider, Jan Hofer." Trier : Universität Trier, 2019. http://d-nb.info/1197808698/34.
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Liu, Dehua. "Thermodynamic and glass transition behavior in CO2-Polymer systems emphasizing the surface region." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1149020480.
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Anjos, Roberto Meigikos dos. "Caracterização do processo de fusão - fissão em sistemas nucleares." Universidade de São Paulo, 1992. http://www.teses.usp.br/teses/disponiveis/43/43131/tde-15082012-160415/.
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Medidas das seções de choque de fusão, de processos fortemente amortecidos e de espalhamento elástico foram realizadas para os sistemas 16,17,18O + 10,11B e 19F + 9Be no intervalo de energia de bombardeio compreendido entre 22 ELAB64 Mev. São apresentadas evidências de que processos binários fortemente amortecidos observados nestes sistemas originam-se preferencialmente de um processo de fusão-fissão e não de um mecanismo de orbiting dinuclear. A importância relativa do processo de fusão-fissão nestes sistemas muito leves é comprovada pelos resultados experimentais, que indicam a ocorrência de um processo de fissão de um núcleo composto estatisticamente equilibrado, assim como por cálculos de modelos teóricos. Os números atômicos e os de massa dos produtos de reação e dos resíduos de evaporação foram identificados usando-se duas câmaras de ionização e um sistema de tempo de voo.Cross sections for fusion, strongly energy-damped processes and elastic scattering were measured for the 16 ,17, 18O + 10 11B and 19F + 9Be systems in the energy range 22 ELAB 64 HeV. Evidence that the fully energy-damped binary products observed in these reactions originate from a fusion-fission process, rather than through a deep-inelastic orbiting mechanism, is presented. The relative importance of the fusion-fission process in these very light systems is supported by experimental results which points towards the fission of a statistically equilibrated compound nucleus and also by model calculations. Charges and masses of the reaction products and evaporation residues were indentified using two ionization chamber and a time-of-flight system.
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Stam, Carson A. "Using Biophysical Geospatial and Remotely Sensed Data to Classify Ecological Sites and States." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1389.
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Monitoring and identifying the state of rangelands on a landscape scale can be a time consuming process. In this thesis, remote sensing imagery has been used to show how the process of classifying different ecological sites and states can be done on a per pixel basis for a large landscape.
Twenty-seven years' worth of remotely sensed imagery was collected, atmospherically corrected, and radiometrically normalized. Several vegetation indices were extracted from the imagery along with derivatives from a digital elevation model. Dominant vegetation components from five major ecological sites in Rich County, Utah, were chosen for study. The vegetation components were Aspen, Douglas-fir, Utah juniper, mountain big sagebrush, and Wyoming big sagebrush. Training sites were extracted from within map units with a majority of one of the five ecological sites.
A Random Forests decision tree model was developed using an attribute table populated with spectral biophysical variables derived from the training sites. The overall out-of-bag accuracy for the Random Forests model was 97.2%. The model was then applied to the predictor spectral and biophysical variables to spatially map the five major vegetation components for all of Rich County. Each vegetation class had greater than 90% accuracies except for Utah juniper at 81%. This process is further explained in chapter 2.
As a follow-on effort, we attempted to classify vegetation ecological states within a single ecological site (Wyoming big sagebrush). This was done using field data collected by previous studies as training data for all five ecological states documented for our chosen ecological site. A Maximum Likelihood classifier was applied to four years of Landsat 5 Thematic Mapper imagery to map each ecological state to pixels coincident to the map units correlated to the Wyoming big sagebrush ecological site. We used the Mahalanobis distance metric as an indicator of pixel membership to the Wyoming big sagebrush ecological site. Overall classification accuracy for the different ecological states was 64.7% for pixels with low Mahalanobis distance and less than 25% for higher distances.
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Grixti, Ivan. "Analysing the impact of the transition from an historical cost to a fair value model of accounting for preparers, auditors and users of the financial statements of listed companies in Malta : an island state economy." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/372327/.
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International Financial Reporting Standards (IFRSs) are moving away from being based on an historical cost model of accounting towards one based on fair values. Such changes have implications for the preparers, auditors and users of financial reports. While much attention has been focused on the technical aspects of the transition to fair value accounting, there has been almost no consideration of the impact of these changes on those who prepare, audit and use financial reports. International Accounting Standards and, subsequently, IFRSs have been incorporated into Maltese company law since 1995. More recently, as a Member State of the European Union, Malta has been required to incorporate IFRSs (as modified by the EU) into its national law. This thesis explores the impact of the transition towards fair value accounting on the preparers and auditors of the financial reports of Maltese listed companies. An exploratory, inductive approach is adopted which uses the grounded theory method (Glaser & Strauss 1967) to understand the effects on the patterns of behaviour of the preparers, auditors and users of financial reports arising from the transition to fair value accounting. Interviews were conducted with those responsible for the preparation of the financial reports of those companies listed on the Malta Stock Exchange that experienced such a transition as well as with the companies’ auditors. The main themes that emerge from the first analysis of the interview material relate to the perceived near absence of markets for assets in Malta, concerns about the understandability of fair value accounting for users of financial reports, and the perceived primacy of the income statement. These themes were identified after transcribing and analysing the interview data collected. However, themes as an output of analysis are insufficient, as grounded theory necessitates the conceptualisation of the data. Moreover, the research was driven by analysis that required further theoretical sampling and thus interviews were carried out with users; namely, stock-brokers and investors. Additionally the analysis required theoretical sampling from a country that has a similar set-up to Malta; thus, Trinidad & Tobago was selected for data comparison in this regard. This theory is developed through the iterative process of constant comparison and analysis of the interview material as well as online data and listed entities’ financial reports. The theory contended that there is a tension between the regulatory framework and the determination of the dividends being proposed by companies. Such a tension evolves from users’ lack of understandability of what fair value adjustments represent; for example, unrealised positive amounts being treated as available for distribution. The resolution of this tension is seen to be through a “meaning-making process”. This “meaning-making process” refers to the latent patterns of behaviour engaged into by preparers, auditors and stock-brokers throughout all six stages of the financial reporting process i.e. from the preparation and review of the financial statements right through to their approval by the shareholders gathered at the AGM. Thus, a process of funnelling, jargonising, pre-empting, briefing, elaborating, explaining and clarifying is engaged in. The research contributes to interpretive accounting research by developing explanations of the effect of fair value accounting on significant actors in an island economy.
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Ghanem, Antoine. "Analyse conformationnelle de polyesters thermotropes." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376053879.
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Kochems, Jonathan Antonius. "Verification of asynchronous concurrency and the shaped stack constraint." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:cd487639-0e7f-4248-9405-e05e8a8383d5.
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In this dissertation, we study the verification of concurrent programs written in the programming language Erlang using infinite-state model-checking. Erlang is a widely used, higher order, dynamically typed, call-by-value functional language with algebraic data types and pattern-matching. It is further augmented with support for actor concurrency, i.e. asynchronous message passing and dynamic process creation. With decidable model-checking in mind, we identify actor communicating systems (ACS) as a suitable target model for an abstract interpretation of Erlang. ACS model a dynamic network of finite-state processes that communicate over a fixed, finite number of unordered, unbounded channels. Thanks to being equivalent to Petri nets, ACS enjoy good algorithmic properties. We develop a verification procedure that extracts a sound abstract model, in the form of an ACS, from a given Erlang program; the resulting ACS simulates the operational semantics of the input. Using this abstract model, we can conservatively verify coverability properties of the input program, i.e. a weak form of safety properties, with a Petri net model-checker. We have implemented this procedure in our tool Soter, which is the first sound verification tool for Erlang programs using infinite-state model-checking. In our experiments, we find that Soter is accurate enough to verify a range of interesting and non-trivial benchmarks. Even though ACS coverability is Expspace-complete, Soter's analysis of these verification problems is surprisingly quick. In order to improve the precision of our verification procedure with respect to recursion, we investigate an extension of ACS that allows pushdown processes: asynchronously communicating pushdown systems (ACPS). ACPS that satisfy the empty-stack constraint (a pushdown process may receive only when its stack is empty) are a popular subclass of ACPS with good decision and complexity properties. In the context of Erlang, the empty stack constraint is unfortunately not realistic. We introduce a relaxation of the empty-stack constraint for ACPS called the shaped stack constraint. Stacks that fit the shape constraint may reach arbitrary heights. Further, a process may execute any communication action (be it process creation, message send or retrieval) whether or not its stack is empty. We prove that coverability for shaped ACPS, i.e. ACPS that satisfy the shaped constraint, reduces to the decidable coverability problem for well-structured transition systems (WSTS). Thus, shaped ACPS enable the modelling and verification of a larger class of message passing programs. We establish a close connection between shaped ACPS and a novel extension of Petri nets: nets with nested coloured tokens (NNCT). Tokens in NNCT are of two types: simple and complex. Complex tokens carry an arbitrary number of coloured tokens. The rules of a NNCT can synchronise complex and simple tokens, inject coloured tokens into a complex token, and eject all tokens of a specified set of active colours to predefined places. We show that the coverability problem for NNCT is Tower-complete, a new complexity class for non-elementary decision problems introduced by Schmitz. To prove Tower-membership, we devise a geometrically inspired version of the Rackoff technique, and we obtain Tower-hardness by adapting Stockmeyer's ruler construction to NNCT. To our knowledge, NNCT is the first extension of Petri nets (belonging to the class of nets with an infinite set of token types) that is proven to have primitive recursive coverability. This result implies Tower-completeness of coverability for ACPS that satisfy the shaped stack constraint.
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MAGALHAES, WELINGTON F. "Influence de parametres physico-chimiques sur les reactions du positonium en solution." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13218.
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Vaca, Patricia. "Etude de l'anisotropie magnétique et de la compétition entre les instabilités antiferromagnétique et spin-Peierls dans les conducteurs organiques." Grenoble 1, 1988. http://www.theses.fr/1988GRE10112.
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Recherche des phenomenes physiques qui gouvernent la stabilisation des etats fondamentaux antiferromagnetiques et spin-pereils des sels de radicaux ioniques de stoechiometrie 2:1. Caracteristiques experimentales de ces deux instabilites dans la phase paramagnetique. Description de modeles 1d adaptes a la discussion des proprietes physiques de ces sels. Etude de nouveaux sels du groupe du tetrathiafulvaline et mise en evidence d'un arrangement structurel nouveau. Caracterisation par la theorie de la resonance antiferromagnetique de la plupart de ces sels, presentant un etat fondamental antiferromagnetique. Discussion qualitative de la competition entre etats fondamentaux antiferromagnetiques et spin-pereils compte tenu de l'importance de la localisation electronique et de la nature des couplages interchaines
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Guibert, Quentin. "Sur l’utilisation des modèles multi-états pour la mesure et la gestion des risques d’un contrat d’assurance." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10256/document.
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La mise en place de Solvabilité II conduit les actuaires à s'interroger sur la bonne adéquation entre modèles et données. Aussi, cette thèse a pour objectif d'étudier plusieurs approches statistiques, souvent méconnues des praticiens, permettant l'utilisation de méthodes multi états pour modéliser et gérer les risques individuels en assurance. Le Chapitre 1 présente le contexte général de cette thèse et permet de faire positionner ses principales contributions. Nous abordons les concepts de base liés à l'utilisation de modèles multi-états en assurance et décrivons les techniques d'inférence classiques adaptées aux données rencontrées, qu'ils soient markoviens ou non-markoviens. Pour finir, nous présentons comment il est possible d'utiliser ces modèles pour la gestion des risques de crédit. Le Chapitre 2 se concentre sur l'utilisation de méthodes d'inférence non-paramétriques pour la construction de lois d'incidence en assurance dépendance. Puisque plusieurs causes d'entrée sont susceptibles d'intervenir et d'intéresser les actuaires, nous nous concentrons sur une méthode utilisée pour l'estimation de modèles multi-états markoviens en temps continu. Nous comparons, dans un second temps, ces estimateurs à ceux utilisés classiquement par les praticiens tires de l'analyse de survie. Cette seconde approche peut comporter des biais non négligeables car ne permettant pas d'appréhender correctement l'interaction possible entre les causes. En particulier, elle comprend une hypothèse d'indépendance ne pouvant être testée dans le cadre de modèles à risques concurrents. Notre approche consiste alors à mesurer l'erreur commise par les praticiens lors de la construction de lois d'incidence. Une application numérique est alors considérée sur la base des données d'un assureur dépendanceWith the implementation of the Solvency II framework, actuaries should examine the good adequacy between models and data. This thesis aims to study several statistical approaches, often ignored by practitioners, enabling the use of multi-state methods to model and manage individual risks in insurance. Chapter 1 presents the general context of this thesis and positions its main contributions. The basic tools to use multi-state models in insurance are introduced and classical inference techniques, adapted to insurance data with and without the Markov assumption, are presented. Finally, a development of these models for credit risk is outlined. Chapter 2 focuses on using nonparametric inference methods to build incidence tables for long term care insurance contracts. Since there are several entry-causes in disability states which are useful for actuaries, an inference method for competing risks data, seen as a Markov multi-state model in continuous time, is used. In a second step, I compare these estimators to those conventionally used by practitioners, based on survival analysis methods. This second approach may involve significant bias because the interaction between entry-causes cannot be appropriately captured. In particular, these approaches assume that latent failure times are independent, while this hypothesis cannot be tested for competing risks data. Our approach allows to measure the error done by practitioners when they build incidence tables. Finally, a numerical application is considered on a long term care insurance dataset
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Lohani, Sapana. "Linking ecosystem services with state-and-transition models to evaluate rangeland management decisions." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/314685.
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Rangelands are a major type of land found on all continents. Though they comprise around 70% of the world's land area, knowledge of rangelands is limited and immature. Rangelands supply humans with food and fiber at very low energy costs compared to cultivated lands. They are inherently heterogeneous, highly variable in time and space. Rangeland management needs to consider the impacts of long-term vegetation transition. It needs a conceptual framework defining potential vegetation communities, describing the management induced transition of one vegetation community to another, and documenting the expected benefits provided by the various potential vegetation communities. The most widely used conceptual unit in the rangeland discipline is the "ecological site". Ecological sites can be an effective unit that should respond to management consistently and can help managers understand the site's potential to meet human needs. A state and transition model (STM) brings ecological sites and their potential vegetative states together to build a conceptual framework showing the major causes of transitions between states of an ecological site and thus helping make adaptive management decisions. Within the STM there is a need for an indicator of ecosystem health. Ecosystem services can be important to evaluate alternative states. Ecosystem services do not pass through a market for valuation, though often the cost would be very high if, through mismanagement, the ecosystem is no longer capable of providing those services. Vegetation communities are constantly facing reversible or irreversible transitions triggered by natural events and/or management actions. The framework generated in this study is significant in using remote sensing to generate state and transition models for a large area and in using ecosystem services to evaluate natural and/or management induced transitions as described in the STM. This dissertation addresses the improvement of public rangelands management in the West. It applies geospatial technologies to map ecological sites and states on those sites, characterizes transitions between states and selects a desired state to manage towards based on a systematic assessment of the value of flows of environmental services. The results from this study are an evaluation of improved draft ecological site maps for a larger area using remote sensing images, a simplified state-and-transition model adapted to remote sensing capabilities to study transitions due to climatic events and management practices, and a constrained optimization model that incorporates ecosystem services and the simplified STM to evaluate management costs and conservation benefits. The study showed that brush treatment is the most effective management practice to cause state transitions. The highest increase in the high cover state was by 24%. Areas under grazing and drought show slow transitions from brush to grass and also after prescribed fire vegetation take at least two years to recover.
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Van, Scoyoc Matthew W. "A QUANTITATIVE APPROACH TO THE DEVELOPMENT OF ECOLOGICAL SITES AND STATE-AND-TRANSITION MODELS." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3075.
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The interaction of land-use and climate can cause non-linear “state” changes in ecosystems, characterized by persistent differences in structure and function. Changes in land-use and climate on the Colorado Plateau may be driving many ecosystems toward undesired states where energy-intensive measures are required to return to previous states. Landscape classification systems based on “ecological potential” offer a robust framework to evaluate ecological conditions. Ecological sites are a popular landscape classification system based on long-term ecological potential and are widely used throughout the western US. Ecological sites have been described extensively for rangelands and woodlands on DOI Bureau of Land Management lands; however, they have yet to be described on USDA Forest Service (USFS) lands. In this thesis, I describe a statistical approach to ecological site delineation and the development of state-and-transition models, diagrams that illustrate ecosystem dynamics and responses to disturbances. In Chapter 2, I used a large inventory dataset and multivariate statistical procedures to classify plots based on life zone, soils, and potential vegetation, effectively delineating statistical ecological site-like groups. Most of the statistical ecological sites matched ecological sites already described by the USDA Natural Resources Conservation Service (NRCS). Additionally, I described one new ecological site that has not been described by the NRCS in the Colorado Plateau region. In Chapter 3, I examined empirical evidence for alternative states in mountain ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and upland piñon-juniper ecosystems. Using multivariate statistical procedures, I found that plots cluster into groups consistent with generalized alternative states identified in a priori conceptual models. Additionally, I showed that ponderosa pine clusters were true alternative states and piñon-juniper clusters were not true alternative states because they were confounded by similarities in climate. Ponderosa pine clusters were differentiated by overstory ponderosa pine density and corresponded to three states: current potential, high fuel load, and reduced overstory. These results illustrate the range of ecosystem variability that is present throughout the study area and present evidence for alternatives states caused by historical land-use. This project is the first to propose ecological sites and state-and-transition models on USFS lands in this region. These techniques could be applied to areas that do not have formally described ecological sites and state-and-transition models and could help identify ecological sites that may have been overlooked using other means of delineation. Additionally, these methods can be used to evaluate the range of ecological variability throughout an area of interest and to improved understanding of ecosystem dynamics.
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Cobb, Richard C., Katinka X. Ruthrof, David D. Breshears, Francisco Lloret, Tuomas Aakala, Henry D. Adams, William R. L. Anderegg, et al. "Ecosystem dynamics and management after forest die-off: a global synthesis with conceptual state-and-transition models." WILEY, 2017. http://hdl.handle.net/10150/626548.
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Broad-scale forest die-off associated with drought and heat has now been reported from every forested continent, posing a global-scale challenge to forest management. Climate-driven die-off is frequently compounded with other drivers of tree mortality, such as altered land use, wildfire, and invasive species, making forest management increasingly complex. Facing similar challenges, rangeland managers have widely adopted the approach of developing conceptual models that identify key ecosystem states and major types of transitions between those states, known as "state-and-transition models" (S&T models). Using expert opinion and available research, the development of such conceptual S&T models has proven useful in anticipating ecosystem changes and identifying management actions to undertake or to avoid. In cases where detailed data are available, S&T models can be developed into probabilistic predictions, but even where data are insufficient to predict transition probabilities, conceptual S&T models can provide valuable insights for managing a given ecosystem and for comparing and contrasting different ecosystem dynamics. We assembled a synthesis of 14 forest die-off case studies from around the globe, each with sufficient information to infer impacts on forest dynamics and to inform management options following a forest die-off event. For each, we developed a conceptual S&T model to identify alternative ecosystem states, pathways of ecosystem change, and points where management interventions have been, or may be, successful in arresting or reversing undesirable changes. We found that our diverse set of mortality case studies fit into three broad classes of ecosystem trajectories: (1) single-state transition shifts, (2) ecological cascading responses and feedbacks, and (3) complex dynamics where multiple interactions, mortality drivers, and impacts create a range of possible state transition responses. We integrate monitoring and management goals in a framework aimed to facilitate development of conceptual S&T models for other forest die-off events. Our results highlight that although forest die-off events across the globe encompass many different underlying drivers and pathways of ecosystem change, there are commonalities in opportunities for successful management intervention.
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Berretil, Slimane. "Proprietes electroniques des semi-conducteurs magnetiques gamo : :(4)s::(8), gamo::(4)se::(8), gamo::(4)se::(4)te::(4) et ganb::(4)s::(8)." Paris 6, 1987. http://www.theses.fr/1987PA066262.
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Etudes effectuees en vue de preciser la nature des electrons qui participent ala conduction et au magnetisme de ces composes. Les composes, caracterises par la presence d'amas tetraedriques des ions metalliques mo et nb dans les bas etats d'oxydation, revelent des proprietes de magnetisme itinerant repondant au modele de stoner-wohlfarth avec les densites d'etats les plus elevees observees dans des composes intermetalliques 3d ou 4d. La rpe a confirme que les raies observees correspondant aux ions metalliques dans un etat s = 3/2 (ions mo**(3+) et nb**(3+)); leur elargissement est d'origine dipolaire retrecie par echange et les valeurs des integrales d'echange obtenues sont en bon accord avec celles obtenues a partir des temperatures de curie
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Sandström, Glenn. "Ready, Willing and Able : The Divorce Transition in Sweden 1915-1974." Doctoral thesis, Umeå universitet, Centrum för befolkningsstudier (CBS), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-60216.
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This thesis attempts to extend the historical scope of divorce research in Sweden by providing an analysis ofhow the variations in the divorce rate over time and across geographical areas are connected to the economic, normative and institutional restructuring of Swedish society during the period 1915-1974. The thesis finds that the economic reshaping of Sweden into a modern market economy is at the center of the process that has resulted in decreased marital stability during the twentieth century. The shift from a single- to a dual-provider model and an increased integration of both men and women into market processes outside the family have resulted in lowered economic interdependence between spouses, which in turn has decreased the economic constraints to divorce. This conclusion is supported by the empirical finding that indicators of female economic self-sufficiency are associated with increased propensities for divorce, during the entire period under research in this thesis. That changes in the constraints experienced by women have been important is further emphasized by the finding that women have been more prone than men to initiate divorce, and that this gendered pattern of divorce was established already during the early twentieth century in Sweden.The results further indicate that the growth of divorce is connected not only to a shift in the provider model but also to the way sustained economic growth has resulted in a general increase in the resources available to individuals, as proposed by the socio-economic growth hypothesis. During the 1920s and 1930s, high-strata groups, such as lawyers, journalists, engineers and military officers, exhibited a divorce rate on the same level as in the general population of Sweden today. By the early 1960s, however, this positive associa- tion between social class and divorce had changed: by then it was rather couples in working-class occupations who exhibited the highest probability of divorce, which is a pattern that appears to have persisted since then. These findings indicate that a general increase and more even distribution of economic resources betweenboth genders and social classes have facilitated individuals’ possibilities to sustain themselves independent of family ties. This democratization in the access to divorce has meant that growing segments of the populationhave gained the means to act on a demand for divorce.However, another result of the thesis is that it is not possible to limit the analysis to a strictly economic perspective. Rather, economic changes have interacted with and been reinforced by changes in values, as wellas in institutions, during the periods when widespread and rapid behavioral change has occurred. In Sweden, like in most other Western countries, this was primarily the case during the 1940s and a period covering approximately the second half of the 1960s and first half of the 1970s. The studies of the thesis suggest that these two periods of rapid growth in the divorce rate stand out as periods in Swedish history when attitudes also changed more rapidly toward values that can be regarded as permissive, secular and more open to indi- vidual freedom of choice. Trenchantly, these two periods also correspond to the two harvest periods in Social Democratic welfare state policy. In the thesis it is argued that the marked increase in government services and social security at these time points integrated with and reinforced economic restructuring in a way that worked to “de-familializate” individuals by making them less dependent on family ties for social security. Institutional changes of this type have been particularly important for making single life more feasible for women and low- income groups. In the thesis, it is argued that the timings of substantial behavioral change become difficult to understand if the analytical perspective does not explicitly incorporate how such contextual-level changes in values and institutions have integrated with changes in the provider model and the economy during thesedynamic periods of the divorce transition in Sweden.
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Woo, Pao-sun Pauline, and 胡寶璇. "Applications of age-period-cohort and state-transition Markov models in understanding cervical cancer incidence trends and evaluating thecost-effectiveness of cytologic screening." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B36900400.
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Guichard, Vincent. "Etude par spectrometrie raman de resonnance d'amines a l'etat de radical-cation et a l'etat triplet : contribution a l'etude des etats radicalaires et excites des derives benzeniques." Paris 6, 1988. http://www.theses.fr/1988PA066276.
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Etude structurale par spectrometrie raman de resonance des etats monocationique et triplet de quelques amines aromatiques, composes modeles de photochimie. Analyse des spectres de plusieurs especes structuralement proches. On montre que les etats ionises et triplet des benzenes substitues par des groupes mesomeres donneurs ont plusieurs points communs qui resultent d'interactions orbitalaires analogues entre le cycle benzenique et le substituant
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Woo, Pao-sun Pauline. "Applications of age-period-cohort and state-transition Markov models in understanding cervical cancer incidence trends and evaluating the cost-effectiveness of cytologic screening." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36900400.
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Kangoye, Sékou. "Elaboration d'une approche de vérification et de validation de logiciel embarqué automobile, basée sur la génération automatique de cas de test." Thesis, Angers, 2016. http://www.theses.fr/2016ANGE0017/document.
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Un système embarqué est un système électronique et informatique autonome dédié à une tâche précise. Dans le secteur de l’automobile, le nombre de systèmes embarqués dans les voitures a considérablement augmenté au cours de ces dernières années et va certainement continuer à augmenter. Ces systèmes sont dédiés entre autres, à la sécurité, au confort de conduite,et à l’assistance à la conduite. Cette croissance des systèmes est associée avec une croissance en taille des logiciels qui les contrôlent. En conséquence, leur gestion(système et logiciel) devient de plus en plus complexe et problématique. Par ailleurs, la concurrence dans le secteur automobile est très féroce et les temps de mise sur le marché sont de plus en plus courts. Ainsi, pour garantir le bon fonctionnement des systèmes en général et du logiciel en particulier, étant donné leur complexité,et aussi les délais courts de mise sur le marché des produits automobiles, de nouvelles méthodes de développement doivent être considérées. Ainsi, de nombreuses méthodes de développement, incluant de nouveaux standards (de développement) et approches automatiques ont émergé au cours de ces dernières années. Dans le cas particulier de la vérification et validation de logiciel, une des activités critiques qui a connu une avancée significative est la génération de cas de test, avec l’avènement d’approches automatiques.Malgré cela, ces approches peinent souvent à s’imposer en milieu industriel. Une des raisons est que celles ci sont souvent peu adaptées ou peu utilisées dans un contexte industriel.Dans ce contexte, cette thèse vise à proposer une approche de vérification et de validation de logiciels embarqués, basée sur la génération automatique de cas de test. Pour cela, nous avons mis en place une approche permettant de représenter sous forme de modèles abstraits les spécifications d’un logiciel, puis de générer à partir de ces modèles un ensemble de cas de test en considérant en particulier le critère de couverture MC/DCAn embedded system is a system that performs a specific task and has a computer embedded inside. In the automotive sector, the amount of embedded systems in the vehicle has risen dramatically in recent years and is set to increase. They deal essentially with safety, comfort, and driving assistance. Furthermore, the increase in number and complexity of the systems is associated with a growth in software. As a consequence, their management (system and software) have become more and more complex and problematic. Also, the competition and time-to-market in the automotive industry are very tough. Thus, to guarantee the efficiency and reliability of the embedded systems in the vehicle in general and the software in particular, in view of the complexity as well as the competition and time-to-market law, new development methods should be considered. Therefore, new development methods including new standards, and automatic approaches have emerged over the last years. In the particular case of embedded software verification and validation, one of the most critical activities that has experienced a significant progress is test case generation with the advent of automatic approaches. Despite this, these approaches are not widely used or are not well adapted in industrial context. In that context, our goal in this PhD. thesis is to propose a new verification and validation approach, based on automatic test case generation of embedded embedded. Thus, we have set up an approach that automatically generates test cases, with respect to the MC/DC criterion, from abstract models of the software specifications expressed in the form of state-transition models
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Le, Bourlot Jacques. "Calcul de probabilites de transition d'intercombinaison entre les etats x **(1)sigma ::(g)**(+) et a **(3)pi ::(v) de c::(2) carbone moleculaire : application a l'equilibre de c::(2) dans les nuages interstellaires diffus." Paris 7, 1987. http://www.theses.fr/1987PA077128.
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Hliwa, Mohamed. "Traitement simplifie des interactions moleculaires en chimie quantique." Toulouse 3, 1988. http://www.theses.fr/1988TOU30038.
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Calculs ab initio sur le systeme hautement degenere cr h: mise en evidence d'un fort couplage entre etats ioniques et neutres et analyse des fonctions d'onde dans une description diabatique. Proposition d'une methode perturbative pour calcul des energies de dispersion entre un systeme versatil a (decrit dans une grande base) et un systeme quasi passif b (traite a l'approximation en coeur gele et caracterise par sa polarisabilite); calcul scf + ci de (a + b gele), du champ electrique exerce par a sur b, et de ses fluctuations, a l'aide d'un hamiltonien effectif; application a l'etude des courbes de potentiel des premiers etats excites des molecules diatomiques de ar avec na, k ou mg. Emploi de la theorie des pseudopotentiels et des potentiels modeles pour le calcul de potentiels impulsifs d'atomes inertes transferables a des systemes moleculaires; a partir de ces potentiels, calcul d'energies de dispersion applicable a la spectroscopie d'atomes alcalins en matiere de gaz rare
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Hernandez, Alexander J. "Spatiotemporal Modeling of Threats to Big Sagebrush Ecological Sites in Northern Utah." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/957.
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This study tested the performance of classification, regression, and ordination techniques to evaluate the spatiotemporal dynamics of threats to big sagebrush ecological sites. The research was focused on invasion by annual exotic grasses and encroachment by woodlands. We sought to identify those areas that have had a persistent coverage of cheatgrass (Bromus tectorum) in big sagebrush ecological sites. We took advantage of the contrast in greenness between multi-temporal (within one year) remotely sensed vegetation indices captured in the spring and summer to find a distinct phenological signature that allowed mapping cheatgrass. We utilized support vector machines (SVM) to classify three temporal scenarios for which field data sets were available. SVM performed very well with accuracies of 70% (producer's) and 95% (user's) for the class of interest (presence of cheatgrass). This was the focus of chapter 2. In chapter 3 we report the development of vegetation continuous fields (VCF) for three years of interest 1996, 2001, and 2007 in order to detect active woodland encroachment. We prepared VCF for shrubs, trees, herbaceous vegetation, and bare ground using a suite of remotely sensed spectral reflectance, vegetation indices, and transformations. We compared the performance of multivariate regression trees (MRT) and random forests (RF) to develop the VCF multi-temporal series. RF outperformed MRT in both accuracy and ability to appropriately map the continuum of percent cover across large landscapes. We estimate that 17,570 hectares of big sagebrush lands showed encroachment by woodlands. Our goal in chapter 4 was to develop a similarity index for large rangeland landscapes. Trend assessments field sites and a long-term annual series (1984 - 2008) of remotely sensed imagery were used in conjunction with multidimensional scaling (MDS) to measure ecological distance to undesired states such as invasion by exotic annuals and encroachment by woodlands. In this chapter our units of analysis were soil-mapping units, which were predominantly composed of one ecological site (>60%). Our MDS results show that different ecological sites can be identified in the reduced MDS statistical space. The observed transitions and trajectories of mountain, Wyoming, and basin big sagebrush sites correlated well with the ecological expectation in semiarid lands. We anticipate that managers can use our protocols to update ecological site descriptions and state and transition models from a remotely sensed perspective.
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Vestin, Albin, and Gustav Strandberg. "Evaluation of Target Tracking Using Multiple Sensors and Non-Causal Algorithms." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-160020.
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Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct associations between measurements and tracks are crucial for improving the tracking performance with non-causal algorithms.
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Lauri, Marcus. "Narratives of governing : rationalization, responsibility and resistance in social work." Doctoral thesis, Umeå universitet, Statsvetenskapliga institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-119783.
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For many years, Sweden has had a reputation for having a comprehensive and women friendly welfare state. However, as in many other European countries during the past few decades, the organization and governing of welfare has undergone profound changes. Through interviews with social workers and the application of theories of governmentality, this thesis analyzes the expressions and consequences of such current organization and governing. One result is that the introduction of meticulous documentation practices of social workers contact with clients, regulate their interaction and constitute a control over both client and social worker. Another result is that the current organization fragments labor and awards more authority to managers, which functions to produce loyalty to the organization and management, rather than clients. This is expressed in demands not to voice protest, as it is said to create a bad mood. It is also expressed in demands to spend as little as possible on clients; short duration of treatment, preference for outpatient treatment and by making it difficult to receive financial support. This austerity is legitimized through the intermeshing of different ideals; budget awareness, evidence that supports short and outpatient treatment and that clients in order to change their course of life should to be allowed or coerced into taking individual responsibility. Another important finding is that the current governing and organization of social work produce distance and detachment, and thus discourage caring subjects. This is a complex process in which an assemblage of different techniques and rationalities undermines the cultivation of a relationship between social worker and client. 1) The ideal of evidence-based practice favors rigid methods over a flexible and holistic approach. 2) Ideals of rationality, closely connected to notions of masculinity and professionalism, value objectivity and devalue and deter the surfacing of emotions. 3) Meticulous practices of documentation reduce the amount of time available to meet clients. 4) Ideals and particular methods designed to promote individual responsibility in clients legitimize social workers distancing themselves from clients’ dependency and needs. 5) A division of labor, in either assessment or treatment, reduces time spent with clients for those who work with assessment and ultimately engage in the rationing of resources. 6) Standardized digital templates, installed to aid in assessments, regulate and proceduralize interactions with the client. 7) Austerity, heavy workloads, individualized responsibility and stress further accentuate distance, as detachment becomes a means to cope with arduous working conditions. The transformation of social work described above produces alienation and a fragmentation of social workers’ collective subjects. Simultaneously, an ethos of caring makes some social workers work extra hard to provide for clients, which ultimately covers for flaws in the system. Although such an ethos of caring allows for the further exploitation of social workers, it is also understood as a means of resistance, which in turn also forms the basis for organized resistance.Sverige har ett internationellt rykte för att ha en omfattande och kvinnovänlig välfärd. Även om riktigheten i en sådan uppfattning sedan länge ifrågasatts har på senare år, likt i många andra Europeiska länder, det svenska välfärdssystemet genomgått en omfattande förändring i avseende på dess räckvidd, men också dess organisering och styrning. Fokus för denna studie är just denna organisering och styrning, och mer specifikt, hur detta påverkar ett av välfärdens kanske mest centrala område: socialt arbete. Genom att intervjua socialarbetare undersöks i denna studie uttryck för och konsekvenser av en sådan förändring, bland annat genom att undersöka hur könsbundna föreställningar och förväntningar är sammanflätade med det sociala arbetets organisering och styrning. I studien konstateras att socialarbetare erfar att deras arbete genomgått omfattande förändringar, vilket kopplas ihop med både organiseringen och styrningen av det sociala arbetet. Detta uttrycks både i de ideal som kringgärdar arbetet men också i dominerande arbetssätt. En sådan förändring är införandet av omfattande dokumentationsprocedurer av socialarbetarens arbete och kontakt med klienter, vilket medför att kontakten med klienterna blir ytligare. Dokumentationsprocedurerna utgör också en sorts kontroll av både klienterna och socialarbetarna själva. En annan förändring som konstateras är att nya organisationsmodeller och en förändrad ledarskapskultur skapar förväntningar på socialarbetarna att vara lojala med organisationen och ledningen snarare än klienterna. Bland annat utrycks detta genom förväntningar att inte protestera och skapa dålig stämning på arbetsplatsen, men också genom uttalade krav att spendera så lite resurser som möjligt på klienterna; korta behandlingstider, öppenvårdsalternativ och orimligt hårda krav för att få ekonomiskt bistånd. Detta legitimeras genom sammanväxningen av flera olika ideal; budgetmedvetenhet, att klienter inte mår bra av långa institutionsvistelser, men också att klienterna ska tillåtas eller bör tvingas att klara att sig själva. Ett av studiens huvudresultat är att den nuvarande organiseringen och styrningen av socialt arbete skapar avstånd och likgiltighet. Genom flera sammankopplade ideal och arbetssätt styrs dagens socialarbetare till att bry sig mindre om de klienter de möter. På så sätt undermineras förutsättningarna för framväxten av en djup relation mellan socialarbetare och klient; 1) Idealet och kravet att socialarbetare ska arbeta utifrån evidens, det vill säga metoder och förhållningssätt som i speciellt utformade utvärderingsmodeller visat sig ha effekt, gör att väl strukturerade och rigida metoder ges företräde. Denna instrumentalisering underminerar ett flexibelt, relationsorienterat och helhetsfokuserat sätt att arbeta. Dessutom gör evidensidealets fokus på enskilda individer och avgränsade utvärderingstider att mer samhällsinriktat kritiskt och långsiktigt inriktat arbete undermineras. 2) Ett rationalitetsideal, tätt sammanbundet med föreställningar om professionalitet och maskulinitet, värderar objektivitet och förmågan att frikoppla socialarbetarens egna känslor från sitt arbete. Detta maskuliniserade professionsideal innebär att empati och solidaritet med klienten undergrävs. 3) Omfattande krav på olika former av dokumentation av det sociala arbetet gör att tiden som socialarbetaren har till sitt förfogande för att besöka och att ha möten med klienten blir knapp. 4) Ett allmänt samhällsideal kring individuellt ansvar och en särskild arbetsmetod (motiverande samtal) som många socialarbetare förväntas lära sig, framhäver klientens eget ansvar för och vilja till förändring. Detta legitimerar ett avståndstagande från klientens behov av hjälp och stöd enligt logiken ”du måste klara detta själv”. 5) En vanligt förekommande uppdelning av socialarbetarnas arbetsuppgifter i en så kallad beställar-utförarmodell gör att vissa socialsekreterare arbetar med hjälp och stöd, medan andra arbetar med bedömningar av klienters behov. De senare, som också har inflytande över resurstilldelning, blir med en sådan organisering av arbetet alltmer frikopplade från den stödjande och hjälpande verksamheten och kontakten med klienten. 6) Standardiserade digitala bedömningsinstrument, skapade för att på ett likvärdigt sätt bedöma klienters behov och dokumentera det sociala arbetet, reglerar och instrumentaliserar kontakten med klienter. 7) Tunga arbetsbördor, individualiserat ansvar och stress, bidrar ytterligare till att skapa avstånd och likgiltighet eftersom det för vissa utgör ett sätt att genomleva en ohållbar arbetssituation. En allmän åtstramning av socialtjänstens resurstilldelning förstås som en viktig orsak till behovet av att skapa ovan distansmekanismer. Men distansen hänger också ihop med en tendens till ett återupplivande av en tidigare dominerande förståelse av marginalisering och sociala problem; där människors nöd ses som ett utslag av dålig karaktär och ett resultat av dåliga individuella val. De förändringar av det sociala arbetets premisser som beskrivits ovan gör att socialarbetarna alltmer görs främmande inför sitt arbete – de alieneras. Detta främmandegörande uttrycks genom att inte kunna identifiera sig med arbetet självt, sina kollegor eller med sig själv. Ett sådant främmandegörande underminerar, eller fragmentiserar, både relationen till klienten, men också en känsla av gemenskap med andra socialarbetare. En gemenskap som kan utgöra ett ”vi” och ligga till grund för att ställa krav, protestera och göra motstånd mot avhumaniserande ideal och reformer. På så vis är främmandegörandet inte bara en konsekvens av dagens organisering och styrning, utan också något som fyller en viktig funktion för en sådan styrning och organisering, och genomförandet av en allmän åtstramning i socialpolitiken. Samtidigt som dagens organisering och styrning av socialt arbete är främmandegörande, slår vissa socialarbetare knut på sig själva och arbetar extra hårt för att täcka upp för systemets brister och krympande resurser, för att trots det svåra läget ändå försöka ge det stöd som de upplever att klienten behöver. Ett sådant historiskt förankrat femininiserat omsorgsideal, dvs känslor av ansvar och empati inför behövande och en ilska inför oförrätter, utgör därmed på samma gång grund för en fördjupad exploatering av socialarbetarna, och ett vardagligt motstånd mot rådande system. I ett läge när flera upplever att kollegialiteten som grund för motstånd på arbetsplatserna underminerats, utgör ett sådant omsorgsideal samtidigt också grunden för organiserat motstånd utanför arbetsplatsen, bortom chefernas insyn, kontroll och härskartekniker. Medan nuvarande styrningssystem underminerar ett visst sorts motstånd, uppstår samtidigt grunden för nya.
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Mallangi, Siva Sai Reddy. "Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229443.
Full textAbstract:
Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.
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"Planned city, shrinking state: Ciudad Guayana's state-led industrialization and its transition to the neoliberal model." Tulane University, 2002.
Find full textAbstract:
The 'Washington Consensus' over Neoliberal reform has fallen significantly short of a consensus, at least among some Latin American nations maintaining vestiges of state-led development strategies. Instead, this study shows how Venezuela is fashioning a 'hybrid' strategy, incorporating elements of statist theories of regional development with free market principles of economic reform such as privatization and decentralization. It examines the extent neoliberal principles have been adopted, assesses the social impacts of different approaches to development, and uncovers social and political forces complicating a shift from state to market-led development Three dimensions of the impacts of retreating states and a strengthening market are analyzed: regional planning, firm performance, and political participation. I conducted in-depth interviews, archival research, and content analysis where the Corporacion Venezolana de Guayana (CVG) built a planned city and Latin America's largest state-owned industrial complex. Legacies of state intervention in Ciudad Guayana were a context for examining how the State, firms, and civil society are negotiating industrial restructuring, increased global competition and political decentralization. My own face-to-face household survey, focus groups, participant observation, and annual survey data reveal impacts of these processes and provide evidence of and reasons for resistance to change My results challenge key assumptions about both statist and market-based development models, and in doing so indicate that neoliberalism's hegemony is subject to reexamination. First, despite origins in competing ideologies, both approaches advocate exploiting comparative advantages in natural resources. Second, contrary to empirical evidence from other resource-based development projects, residents' standard of living was very adequate, indicating long-term returns on public investment associated with state-led capitalism. Third, regardless of global universality and uniformity of neoliberalism, locally implemented policies stopped short of structural reform. Fourth, global economic restructuring has wrought enormous local change independent of neoliberal reform. Industries struggle with global oversupply of commodities, debt, and technological shortcomings; unemployment is increasing; wages are stagnant; and the service sector is growing. Finally, while local actors agree that they must look beyond public enterprise for a development strategy, the centralization associated with state-led development makes it difficult for local government, led by 'La Causa R', to foster participatory democracyacase@tulane.edu
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Yeh, Chih-Wei, and 葉志偉. "Estimation of OD pattern by Non-Gaussian State Space Model with Unknown Transition Matrix." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/87909567251590119789.
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碩士國立交通大學
統計所
88
In this thesis we provide methods for estimating origin-destination demand pattern in the time domain. For doing this we use the state space model, and consider the non-Gaussian state space model to estimate parameters. These techniques rely on Gibbs sampler and Kalman filter. And we apply it to the rapid transit system.
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Hu, Geng-Ming, and 胡耿銘. "Two-state growth with transition model and its application to cancer growth system and therapy development." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/25448371947465938847.
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博士國立臺灣大學
物理研究所
100
Heterogeneous population is common among complex systems in nature. A simple heterogeneous growth model of interest is one with two states which not only compete with each other but exhibit transition phenomenon. In this work, we develop a mathematical model to describe such a system and apply it to fit the real growth data of the prostate cancer spheroid under treatments.
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Chang, Chiayu, and 張家瑜. "Factors affecting the transition state of depression for the elderly in Taiwan - An application of the Cox proportional hazard model in competing risk." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/80316431886090881232.
Full textAbstract:
碩士東海大學
統計學系
100
Due to the rapid decline in fertility and increased longevity in recent years, Taiwan is experiencing a dramatic demographic transition in which the overall proportion of old people in the population is increasing. From many studies, it is evident that there is a steady increase in the incidence and prevalence of depression and related problems among the elderly population. Depression symptoms experienced in late life have serious implications for the health and functioning of older individuals. In addition, it might cause high mortality rates if the depression status of the elderly could not be improved. Thereby, one major task in the elderly population is to deal with the problem of depression. Since many aspects of mental health can be targeted for improvement in health care, the goal of this study is to discuss how the variables related to demographic, self-rated health, physical function and home condition determinants affect the transition state of depression for the elderly in Taiwan by employing Cox proportional hazard model in competing risks. The elderly data collected by the Bureau of Health Promotion of the Department of Health in Taiwan from 1989 to 2003, will be used to explore the variables related to depression symptom which is according to a complete set of depression scale (CES-D) data of the elderly. The old people who were 60 years old and over were first interviewed in 1989 and re-interviewed in 1993, 1996, 1999 and 2003. The Cox proportional hazard model in competing risks is used to explore whether some of the covariates of the factors e.g. demographic characteristics, home conditions, and health characteristics, are related to the three different types of transition about depression, such as transition, reverse transition and repeated transition. No matter the initial state of the elderly is with depression or without depression, the cumulative incidence functions and the Cox proportional hazard model in competing risk reveal that the home condition (economic status) and health characteristics (self-rated health and physical function) are strongly related to the depression of the elderly.
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Chen, Yung-Chi, and 陳勇旗. "Prediction of Home Energy Consumption based on Appliance State Transition Models." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7b2zya.
Full textAbstract:
碩士國立交通大學
資訊科學與工程研究所
106
Nowadays, more and more people concern the energy and environmental issues and would like to manage the use of electric power from a small-scale area such as a house, a building, or community. One of the most important tasks is to forecast the power consumption in next several minutes and/or hours so that people may cooperatively use their appliances in an asynchronous manner to alleviate the peak power consumption of an area. Different from conventional large-scale power consumption forecast schemes which are mainly based on artificial intelligence methods such as artificial neural network, this paper proposes a new approach to predict the energy consumption of a house and building based on appliance state transition models which can be gathered from a nonintrusive load monitoring (NILM) meter. First, the appliance usage patterns of a house or a building are obtained from the NILM meter. Then, appliance state transition models can be established and they can be used to predict the energy consumption of a house or building efficiently. Simulation results indicate that only 3% to 5% prediction error is introduced for a typical house environment.
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Lee, Jisun. "Development and testing of a constrained optimization model for traffic signal plan transition." 2009. http://www.lib.ncsu.edu/theses/available/etd-04292009-105231/unrestricted/etd.pdf.
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Šťastná, Ema. "Role armády ve státě v čase přechodu k demokracii : případová studie civilně-vojenských vztahů v Egyptě." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-347856.
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In connection with the events of the Arab Spring in 2011, the region of northern Africa in particular underwent significant political changes. One of the states in which widespread protests caused the overturn of the authoritarian regime and subsequently established the democratization process was also Egypt, whose case is profoundly analysed in the second part of the thesis. Generally speaking, the thesis is concerned with the analysis of civil-military relations in states characterized by the low political culture. In the first place, it focuses on societies undergoing democratization process where the military traditionally maintains strong position within the state and hence often assumes the role of the leader of the transition. Therefore, the principal objective of the analysis constitutes the role of the army at the time of transition to democracy. At the same time, the thesis poses three research questions aiming partly at the military position, partly at the motives determining the willingness of the military to intervene. In the second part, the thesis analyses the given case through five defined factors which it subsequently examines in two levels: conceptual and interventionist. The goal of the thesis it to explain which factors determine strong position of the army in given praetorian...
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Kalz, Ansgar. "Phase diagrams of two-dimensional frustrated spin systems." Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-F080-B.
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Desai, Uri. "A Comparative Study of Estimation Models for Satellite Relative Motion." Thesis, 2013. http://hdl.handle.net/1969.1/149297.
Full textAbstract:
The problem of relative spacecraft motion estimation is considered with application to various reference and relative orbits. Mean circular and elliptic orbits are analyzed, with relative orbits ranging in size from 1 km to 10 km. Estimators are built for three propagation models: (i) Gim-Alfriend State Transition Matrix, (ii) the J2-Linearized Equations of Motion for Circular Orbits, and (iii) the Clohessy-Wiltshire Equations of Motion. Two alternative models were developed in an attempt to ac- count for unmodeled nonlinearities: (i) Biased Clohessy-Whiltshire Equations, and (ii) J2 -Linearized State Transition Matrix. Two estimation techniques are presented in an attempt to explore and determine which propagation model minimizes the error residual: the linear Kalman filter is presented under the assumption of vector based, GPS-type measurements; the extended Kalman filter is analyzed assuming angle-range, optical-type measurements. Sampling time is varied to look at the effect of measurement frequency. It is assumed that the orbit of one of the satellites, the chief, is known reasonably well.
This work showed that the error residuals from the state estimates were minimized when the propagation technique utilized was the Gim-Alfriend State Transition Matrix. This supports conclusions that are obtained outside of the estimation problem. Additionally, the error residuals obtained when the propagation technique was the Clohessy-Wiltshire Equations is comparable to the more complicated models. Unmodeled nonlinearities affect the magnitude of the error residuals. As expected, the Gim-Alfriend STM comes closest to the truth; for smaller eccentricities (0.005), the Clohessy-Wiltshire EOM show minor deviations from the truth. As the eccentricity increases, the linear models begin to diverge greatly from the true response. The additional two models (the biased CW equations, and the linear STM) show decent performance under specific conditions. The former accounts for some of the unaccounted for nonlinearities. The latter exhibits comparable performance to the Gim-Alfrien STM for circular reference orbits. However, in each case, as the nonlinearity of the problem increases, the accuracy of the model decreases.
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Liu, Shih-Chia, and 劉士嘉. "Multi-State Models for Recurrent Events with Interval Censored Data－An Application of the Depression Transition Status of the Elderly in Taiwan." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/6gn4n4.
Full textAbstract:
博士東海大學
統計學系
101
Many countries have been facing the challenges of aging population over decades. Depressive symptoms in later life of elderly have serious implications for the health and functioning has caused wide public concern. The purpose of this study is to explore the effect of the covariates related to demographic characteristics, home and environment conditions, and health status, on the changing status of depression of old people in Taiwan. A representative panel sample survey data collected in the six waves of “The Longitudinal Sample Survey of Health and Living Status of the Elderly in Taiwan” conducted from 1989 to 2007 by the predecessor organization of the Bureau of Health Promotion, Department of Health is used for analysis. Since cases of depression status are recurrent events with the characteristics of interval censored data, Cox model with interval-censored approach is applied for investigating the variables related to the changing status of depression among the elderly under the assumption that the observations within a subject are mutually independent. However, a major disadvantage of interval censored model is unable to deal with the situation that two or more different events of interest exist simultaneously, a more general method, multi-state model considered as a Markov chain for event history analysis is used to interpret the changing status of depression. To verify the proportional assumption in the conventional Cox model, Aalen’s additive model taking into account instantaneous covariate effects in time is employed as an alternative on a supplement. Also, the scaled Schoenfeld residuals plots are used for investigating the proportional hazard assumption. Furthermore, the transition probabilities for the changing status of depression obtained from Cox and Aalen models are provided. From the results of this study, age, gender, education, spouse, living with children, economic status, self-rated health, ADL function and physical function are significantly related to the depression. Also, the transition probabilities show the death rate has a greater impact on the elderly with initial depression state.
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Czembor, Christina Anne. "Incorporating uncertainty into expert models for management of box-ironbark forests and woodlands in Victoria, Australia." 2009. http://repository.unimelb.edu.au/10187/5801.
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Anthropogenic utilization of forest and woodland ecosystems can cause declines in flora and fauna species. It is imperative to restore these ecosystems to mitigate further declines. In this thesis, I focused on a highly degraded region, the Box-Ironbark forests and woodlands of Victoria, Australia. Rather than mature stands with large trees, stands are currently dominated by high densities of small stems. This change has resulted in reduced populations of many flora and fauna species dependent on older-growth forests and woodlands. Managers are interested in restoring mature Box-Ironbark forests and woodlands through three alternative management strategies: allocating land to National Parks and allowing stands to develop naturally without harvesting, modifying timber harvesting regimes to retain more medium and large trees, or a new ecological thinning technique that retains target habitat trees and removes competing trees to encourage growth of retained stems.The effects of each management strategy are not easy to predict due to complex interactions between intervention and stochastic natural processes. Forest simulation models are often employed to overcome this problem. I constructed state-and-transition simulation models (STSMs) to predict the effects of alternative management actions and natural disturbances on vegetation structure. Due to a lack of empirical data, I relied on the knowledge of experts in Box-Ironbark ecology and management to construct STSMs. Models predicted that the development of mature woodlands under all strategies was minimal over the next 150 years, and neither current harvesting nor ecological thinning is likely to expedite the development of mature stands relative to growth and natural disturbances. However, differences in experts’ opinions led to widely diverging model predictions.
Uncertainty must be acknowledged in model construction because it can affect model predictions. I quantified uncertainty due to four sources – between-expert variation, imperfect expert knowledge, natural stochasticity, and model parameterization – to determine which source caused the most variance in model predictions. I found that models were very uncertain and between-expert uncertainty contributed the majority of variance in model predictions. This brings into question the use of consensus methods in forest management where differences between experts are ignored.
Using uncertain model predictions to make management decisions is problematic because any given action can have many plausible outcomes. I applied several decision criteria to uncertain STSM predictions using a formal decision-making framework to determine the optimal management action in Box-Ironbark forests and woodlands. I found that natural development is the most risk-averse option, while ecological thinning is the most risky option because there is a small likelihood that it will greatly expedite the development of mature woodlands. Rather than selecting one option, managers could rely on a risk-spreading approach where the majority of land is allocated to no-cutting National Parks and a small amount of land is allocated to the other two harvesting strategies. This would allow managers to collect monitoring data for all management strategies in order to learn about effects of harvesting and update model predictions through time using adaptive management.
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Chakrabarti, Rajarshi. "Statistical Mechanical Models Of Some Condensed Phase Rate Processes." Thesis, 2008. http://hdl.handle.net/2005/863.
Full textAbstract:
In the thesis work we investigate four problems connected with dynamical processes in condensed medium, using different techniques of equilibrium and non-equilibrium statistical mechanics.
Biology is rich in dynamical events ranging from processes involving single molecule [1] to collective phenomena [2]. In cell biology, translocation and transport processes of biological molecules constitute an important class of dynamical phenomena occurring in condensed phase. Examples include protein transport through membrane channels, gene transfer between bacteria, injection of DNA from virus head to the host cell, protein transport thorough the nuclear pores etc. We present a theoretical description of the problem of protein transport across the nuclear pore complex [3]. These nuclear pore complexes (NPCs) [4] are very selective filters that monitor the transport between the cytoplasm and the nucleoplasm. Two models have been suggested for the plug of the NPC. The first suggests that the plug is a reversible hydrogel while the other suggests that it is a polymer brush. In the thesis, we propose a model for the transport of a protein through the plug, which is treated as elastic continuum, which is general enough to cover both the models. The protein stretches the plug and creates a local deformation, which together with the protein is referred to as the bubble. The relevant coordinate describing the transport is the center of the bubble. We write down an expression for the energy of the system, which is used to analyze the motion. It shows that the bubble executes a random walk, within the gel. We find that for faster relaxation of the gel, the diffusion of the bubble is greater. Further, on adopting the same kind of free energy for the brush too, one finds that though the energy cost for the entry of the particle is small but the diffusion coefficient is much lower and hence, explanation of the rapid diffusion of the particle across the nuclear pore complex is easier within the gel model.
In chemical physics, processes occurring in condensed phases like liquid or solid often involve barrier crossing. Simplest possible description of rate for such barrier crossing phenomena is given by the transition state theory [5]. One can go one step further by introducing the effect of the environment by incorporating phenomenological friction as is done in Kramer’s theory [6]. The “method of reactive flux” [7, 8] in chemical physics allows one to calculate the time dependent rate constant for a process involving large barrier by expressing the rate as an ensemble average of an infinite number of trajectories starting at the barrier top and ending on the product side at a specified later time. We compute the time dependent transmission coefficient using this method for a structureless particle surmounting a one dimensional inverted parabolic barrier. The work shows an elegant way of combining the traditional system plus reservoir model [9] and the method of reactive flux [7] and the normal mode analysis approach by Pollak [10] to calculate the time dependent transmission coefficient [11]. As expected our formula for the time dependent rate constant becomes equal to the transition state rate constant when one takes the zero time limit. Similarly Kramers rate constant is obtained by taking infinite time limit. Finally we conclude by noting that the method of analyzing the coupled Hamiltonian, introduced by Pollak is very powerful and it enables us to obtain analytical expressions for the time dependent reaction rate in case of Ohmic dissipation, even in underdamped case.
The theory of first passage time [12] is one of the most important topics of research in chemical physics. As a model problem we consider a particle executing Brownian motion in full phase space with an absorbing boundary condition at a point in the position space we derive a very general expression of the survival probability and the first passage time distribution, irrespective of the statistical nature of the dynamics. Also using the prescription adopted elsewhere [13] we define a bound to the actual survival probability and an approximate first passage time distribution which are expressed in terms of the position-position, velocity-velocity and position-velocity variances. Knowledge of these variances enables one to compute the survival probability and consequently the first passage distribution function. We compute both the quantities for gaussian Markovian process and also for non-Markovian dynamics. Our analysis shows that the survival probability decays exponentially at the long time, irrespective of the nature of the dynamics with an exponent equal to the transition state rate constant [14].
Although the field of equilibrium thermodynamics and equilibrium statistical mechanics are well explored, there existed almost no theory for systems arbitrarily far from equilibrium until the advent of fluctuation theorems (FTs)[15] in mid 90�s. In general, these fluctuation theorems have provided a general prescription on energy exchanges that take place between a system and its surroundings under general nonequilibrium conditions and explain how macroscopic irreversibility appears naturally in systems that obey time reversible microscopic dynamics. Based on a Hamiltonian description we present a rigorous derivation [16] of the transient state work fluctuation theorem and the Jarzynski equality [17] for a classical harmonic oscillator linearly coupled to a harmonic heat bath, which is dragged by an external agent. Coupling with the bath makes the dynamics dissipative. Since we do not assume anything about the spectral nature of the harmonic bath the derivation is valid for a general non-Ohmic bath.