Data on (economic) institutions are often available only as observations on ordinal, inherently incomparable properties, which are then typically aggregated to a composite index in the empirical social science literature. From a methodological perspective, the present paper advocates the application of partially ordered set (POSET) theory as an alternative approach. Its main virtue is that it takes the ordinal nature of the data seriously and dispenses with the unavoidably subjective assignment of weights to incomparable properties, maintains a high standard of objectivity, and can be applied in various fields of economics. As an application, the POSET approach is then used to calculate new indices on the stringency of fiscal rules for 81 countries over the period 1985 to 2012 based on recent data by the IMF (2012). The derived measures of fiscal rules are used to test their significance for public finances in a fiscal reaction function and compare the POSET with the composite index approach. (authors' abstract)

A completely satisfactory water distribution network should fulfill its basic requirements such as providing the expected quality and quantity of water with the desired residual pressures during its lifetime. A water distribution network should accommodate the abnormal conditions caused by failures. These types of failures can be classified into two groups / mechanical failures and hydraulic failures. Mechanical failure is caused due to malfunctioning of the network elements such as pipe breakage, power outage and pump failure. On the other hand, hydraulic failure, considers system failure due to distributed flow and pressure head which are inadequate at one or more demand points.This study deals with the calculation of the hydraulic system reliability of an existing water distribution network regarding the Modified Chandapillai model while calculating the partially satisfied nodes. A case study was carried out on a part of Ankara Water Distribution Network, N8-1. After the modeling of the network, skeletonization and determination of nodal service areas were carried out. The daily demand curves for the area were drawn using the data that were taken from SCADA of the water utility. The daily demand curves of different days were joined and one representative mean daily demand curve together with the standard deviation values was obtained. The friction coefficient values of the pipes and storage tank water elevation were taken as other uncertainty parameters for the model. Bao and Mays (1990) approach were carried together with the hydraulic network solver program prepared by Nohutcu (2002) based on Modified Chandapillai model. The sensitivity analysis for the effects of system characteristics and model assumptions were carried out to see the effects of the parameters on the calculations and to investigate the way of improving the hydraulic reliability of the network. The storage tank should be located at a higher level for improving the reliability of the network. Also having the storage tank water level nearly full level helps in improving the reliability in daily management. Moreover, the hydraulic system reliability is highly dependent on the pumps as the lowest reliability factors were the ones with the no pump scenarios. Determining the required pressures for nodes are very important since they are the dominant factors that effects the reliability calculations. On the other hand, friction coefficient parameters and type of probability distribution function do not have dominant effect on the results. Results of this study were helpful to see the effects of different parameters on the hydraulic reliability calculations and for assessment of the methods for improving the reliability for the network.

This thesis contains several results concerning the combinatorics of partially ordered sets (posets) which are either of enumerative or extremal nature. <br><br> The first concerns conjectures of Friedland and Kahn, which state that the (extremal) d-regular graph on N vertices containing both the maximal number of matchings and independent sets of a fixed size is the graph consisting of disjoint union of appropriate number of complete bipartite d-regular graphs on 2d vertices. We show that the conjectures are true in an asymptotic sense, using entropy techniques. <br><br> As a second result, we give tight bounds on the size of the largest Boolean family which contains no three distinct subsets forming an "induced V" (i.e. if A,B,C are all in our family, if C is contained in the intersection of A B, A must be a subset of B). This result, though similar to known results, gives the first bound on a family defined by an induced property. <br><br> We pose both Dedekind-type questions concerning the number of antichains and a Stanley-type question concerning the number of linear extensions in generalized Boolean lattices; namely, products of chain posets and the poset of partially defined functions. We provide asymptotically tight bounds for these problems. <br><br> A Boolean function, f, is called cherry-free if for all triples x,y,z where z covers both x and y, f(z)=1 whenever both f(x)=1 and f(y)=1. We give bounds on the number of cherry-free functions on bipartite regular posets, with stronger results for bipartite posets under an additional co-degree hypotheses. We discuss applications of these functions to Boolean Horn functions and similar structures in ranked regular posets.

The work presented in this thesis falls naturally into two parts. The first part (Chapter 2), is concerned with the benefit of perturbing a population into an immediately undesirable state, in order to improve estimates of a static probability which may improve long-term management. We consider finding the optimal harvest policy for a theoretical harvested population when a key parameter is unknown. We employ an adaptive management framework to study when it is worth sacrificing short term rewards in order to increase long term profits. / Active adaptive management has been increasingly advocated in natural resource management and conservation biology as a methodology for resolving key uncertainties about population dynamics and responses to management. However, when comparing management policies it is traditional to weigh future rewards geometrically (at a constant discount rate) which results in far-distant rewards making a negligible contribution to the total benefit. Under such a discounting scheme active adaptive management is rarely of much benefit, especially if learning is slow. In Chapter 2, we consider two proposed alternative forms of discounting for evaluating optimal policies for long term decisions which have a social component. / We demonstrate that discount functions which weigh future rewards more heavily result in more conservative harvesting strategies, but do not necessarily encourage active learning. Furthermore, the optimal management strategy is not equivalent to employing geometric discounting at a lower rate. If alternative discount functions are made mandatory in calculating optimal management policies for environmental management, then this will affect the structure of optimal management regimes and change when and how much we are willing to invest in learning. / The second part of this thesis is concerned with how to account for partial observability when calculating optimal management policies. We consider the problem of controlling an invasive pest species when only partial observations are available at each time step. In the model considered, the monitoring data available are binomial observations of a probability which is an index of the population size. We are again concerned with estimating a probability, however, in this model the probability is changing over time. / Before including partial observability explicitly, we consider a model in which perfect observations of the population are available at each time step (Chapter 3). It is intuitive that monitoring will be beneficial only if the management decision depends on the outcome. Hence, a necessary condition for monitoring to be worthwhile is that control polices which are specified in terms of the system state, out-perform simpler time-based control policies. Consequently, in addition to providing a benchmark against which we can compare the optimal management policy in the case of partial observations, analysing the perfect observation case also provides insight into when monitoring is likely to be most valuable. / In Chapters 4 and 5 we include partial observability by modelling the control problem as a partially observable Markov decision process (POMDP). We outline several tests which stem from a property of conservation of expected utility under monitoring, which aid in validating the model. We discuss the optimal management policy prescribed by the POMDP for a range of model scenarios, and use simulation to compare the POMDP management policy to several alternative policies, including controlling with perfect observations and no observations. / In Chapter 6 we propose an alternative model, developed in the spirit of a POMDP, that does not strictly satisfy the definition of a POMDP. We find that although the second model has some conceptually appealing attributes, it makes an undesirable implicit assumption about the underlying population dynamics.

Thesis (M.S.)--University of Michigan, 1969.

Thesis (Ph.D.)--Mathematics, Georgia Institute of Technology, 2008. / Committee Chair: Trotter, William T.; Committee Member: Duke, Richard A.; Committee Member: Randall, Dana; Committee Member: Thomas, Robin; Committee Member: Yu, Xingxing

Thesis (M.S.)--University of Michigan, 1969.

abstract: There will always be a need for high current/voltage transistors. A transistor that has the ability to be both or either of these things is the silicon metal-silicon field effect transistor (MESFET). An additional perk that silicon MESFET transistors have is the ability to be integrated into the standard silicon on insulator (SOI) complementary metal oxide semiconductor (CMOS) process flow. This makes a silicon MESFET transistor a very valuable device for use in any standard CMOS circuit that may usually need a separate integrated circuit (IC) in order to switch power on or from a high current/voltage because it allows this function to be performed with a single chip thereby cutting costs. The ability for the MESFET to cost effectively satisfy the needs of this any many other high current/voltage device application markets is what drives the study of MESFET optimization. Silicon MESFETs that are integrated into standard SOI CMOS processes often receive dopings during fabrication that would not ideally be there in a process made exclusively for MESFETs. Since these remnants of SOI CMOS processing effect the operation of a MESFET device, their effect can be seen in the current-voltage characteristics of a measured MESFET device. Device simulations are done and compared to measured silicon MESFET data in order to deduce the cause and effect of many of these SOI CMOS remnants. MESFET devices can be made in both fully depleted (FD) and partially depleted (PD) SOI CMOS technologies. Device simulations are used to do a comparison of FD and PD MESFETs in order to show the advantages and disadvantages of MESFETs fabricated in different technologies. It is shown that PD MESFET have the highest current per area capability. Since the PD MESFET is shown to have the highest current capability, a layout optimization method to further increase the current per area capability of the PD silicon MESFET is presented, derived, and proven to a first order. / Dissertation/Thesis / M.S. Electrical Engineering 2011

Entre os objetivos da engenharia geotécnica está a busca pelo entendimento e previsão do comportamento mecânico dos solos. Para isso, existem basicamente duas abordagens: ensaios de laboratório ou ensaios de campo. Em cada obra o Engenheiro Geotécnico deve julgar quais são os métodos e procedimentos mais indicados de investigação, que resultarão em parâmetros confiáveis de projeto. Os ensaios de campo foram desenvolvidos baseados nos solos argilosos e arenosos em virtude dos comportamentos distintamente bem definidos, especialmente em termos de drenagem. O mesmo ocorre para o ensaio DMT, cuja execução e interpretação são influenciadas pelo tipo de solo e pelas condições de drenagem. O grande desafio, neste caso, está na interpretação dos ensaios em solos cuja solicitação ocorre sob condição de drenagem parcial, como nos casos de barragens de rejeito de mineração, ou em depósitos naturais de solos siltosos, onde esta condição pode levar a erros de interpretação. No DMT, a ocorrência de drenagem parcial influencia tanto na etapa de cravação da lâmina, quanto na etapa de expansão da membrana. Neste sentido, o foco deste trabalho está no problema da dissipação de poropressão durante a expansão da membrana, apresentando procedimentos especiais para realização do ensaio DMT. Serão apresentados dois métodos de interpretação de resultados, visando compensar os erros de interpretação causados pela dissipação parcial de poropressão: Método de Dissipação Completa e, Método de Dissipação Incompleta. Este trabalho foi desenvolvido baseado na realização de ensaios de campo, com uma campanha executada em solo brasileiro argiloso, que serviu de base à interpretação, sendo complementada por 6 ensaios realizados em diferentes sítios na Itália. Os resultados dos ensaios realizados pelo Método de Dissipação Completa foram interpretados através de duas abordagens: Método da Igualdade (analítico) e Método Simplificado. Enquanto a interpretação do Método de Dissipação Incompleta é permitida apenas através de procedimento simplificado. A análise paramétrica apresentou comportamentos similares entre ambas abordagens, demonstrando que a taxa de dissipação é o fator que mais influencia nos resultados. Ao final, os métodos foram aplicados e validados em diferentes locais, apresentando resultados adequados e compatíveis com o comportamento previamente definido através de outros ensaios. / Among the geotechnical engineering goals are the understanding and prediction of soil behavior. For this, there are basically two approaches: laboratory or in situ tests. In this case, the Geotechnical Engineer must judge the most appropriate investigation methods and procedures that will result in reliable design parameters. In situ tests were developed for clay and sand given to the fact that the behavior of these soils is well-defined and drainage conditions are properly controlled. The DMT is no exception, with test and interpretation methods influenced by the drainage conditions. The challenge resides in the interpretation of tests carried out in soils under partial-drainage conditions, such as tailings dams or natural deposits of silty soils, where partial-drainage conditions are taking place around the DMT blade leading to errors on its interpretation. The partial drainage condition influences both the DMT blade penetration phase and the membrane expansion phase. In this sense, this work focus on the problem of the pore pressure dissipation taking place simultaneously to membrane expansion. A non-standard procedure is proposed to sounding the DMT in silts that include two methods for DMT interpretation in order to compensate the errors caused by the partial pore pressure dissipation: Method of Complete Dissipation Curve and Method of Incomplete Dissipation Curve. This work was developed based on tests carried out in Brazilian clay soils to develop the proposed approach that was validated latter in non-standard tests carried out in different Italian sites. The results of the tests performed by the complete dissipation method were interpreted through two approaches: Equality Method (analytical) and Simplified Method, while the interpretation of the incomplete dissipation method is possible only through simplified procedure. The parametric analysis showed that these approaches yield similar results, demonstrating that the dissipation rate is the most important factor in the analysis. At the end, the methods were applied and validated at different sites, showing results that are compatible to previously defined behavior of the soils.

Dans le cadre de cette thèse, nous présentons l’extension des résultats sur le raisonnement avec des bases de croyances totalement ordonnées au cas partiellement ordonné. L’idée est de raisonner avec des bases logiques équipées d’un ordre partiel exprimant la certitude relative et de construire une fermeture déductive partiellement ordonnée. Au niveau syntaxique, nous pouvons soit utiliser un langage exprimant des paires de formules et des axiomes décrivant les propriétés de l’ordre, ou utiliser des formules en relation avec des poids symboliques partiellement ordonnés dans l’esprit de la logique possibiliste. Une sémantique possible consiste à supposer que cet ordre provient d’un ordre partiel sur les modèles. Elle exige la capacité d’induire un ordre partiel sur les sous-ensembles d’un ensemble, à partir d’un ordre partiel sur ses éléments. Parmi plusieurs définitions de relations d’ordre partiel ainsi définies, nous sélectionnons la plus pertinente pour représenter la notion de certitude relative, en accord avec la théorie des possibilités. Nous montrons les limites d’une sémantique basée sur un ordre partiel unique sur les modèles et proposons une sémantique plus générale qui utilise une relation d’ordre partiel entre les ensembles de modèles. Nous utilisons un langage de plus haut niveau qui exprime des conjonctions de paires de formules en relation, avec des axiomes qui décrivent les propriétés de la relation. Nous proposons deux approches syntaxiques pour inférer de nouvelles paires de formules à partir d’une base partiellement ordonnée, et compléter ainsi l’ordre sur le langage propositionnel. L’une des inférences est proche des logiques conditionnelles de Lewis (qui traite le cas totalement ordonné) et d’un travail de Halpern. Elle est également proche du Système P. Nous reprenons la logique possibiliste symbolique proposée par Benferhat et Prade et comparons cette approche avec l’approche par certitude relative. Pour cela nous poursuivons l’étude de la logique possibiliste symbolique en démontrant un résultat de complétude. Nous étudions la question de la traduction d’une base partiellement ordonnée en base possibiliste symbolique et inversement. Nous proposons enfin des pistes pour une implémentation du système d’inférence de certitude relative et du système possibiliste symbolique. / In this thesis, we present results on the extension of the existing methods for reasoning with totally ordered belief bases to the partially ordered case. The idea is to reason from logical bases equipped with a partial order expressing relative certainty and to construct a partially ordered deductive closure. The difficult part lies in the fact that equivalent definitions in the totally ordered case are no longer equivalent in the partially ordered case. At the syntactic level we can either use a language expressing pairs of related formulas and axioms describing the properties of the ordering, or use formulas with partially ordered symbolic weights attached to them in the spirit of possibilistic logic. A possible semantics consists in assuming that the partial order on formulas stems from a partial order on interpretations. It requires the capability of inducing a partial order on subsets of a set from a partial order on its elements so as to extend possibility theory functions. Among different possible definitions of induced partial order relations, we select the one generalizing necessity orderings (closely related to epistemic entrenchments). We study such a semantic approach inspired from possibilistic logic, and show its limitations when relying on a unique partial order on interpretations. We propose a more general sound and complete approach to relative certainty, inspired by conditional modal logics, in order to get a partial order on the whole propositional language. Some links between our approach and several inference systems, namely conditional logic, modal epistemic logic and non-monotonic preferential inference are established. Possibilistic logic with partially ordered symbolic weights proposed by Benferhat and Prade is also revisited and we continue the study by proving a completeness result. A comparison with the relative certainty approach is made via mutual translations. We compare this approach with the relative certainty approach.We study the question of the translation of a partially ordered base into a symbolic possibilistic base and vice versa. The results for this translation highlight different assumptions underlying the two logics. We also offer steps toward implementation tools for the inference of relative certainty and for the symbolic possibilistic system.