927 resultados para Elementary shortest path with resource constraints


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Strategic control is defined as the use of qualitative and quantitative tools for the evaluation of strategic organizational performance. Most research in strategic planning has focused on strategy formulation and implementation, but little work has been done on strategic performance evaluation particularly in the area of cancer research. The objective of this study was to identify strategic control approaches and financial performance metrics used by major cancer centers in the country as an initial step in expanding the theory and practice behind strategic organizational performance. Focusing on hospitals which share similar mandate and resource constraints was expected to improve measurement precision. The results indicate that most cancer centers use a wide selection of evaluation tools, but sophisticated analytical approaches were less common. In addition, there was evidence that high-performing centers tend to invest a larger degree of resources in the area of strategic performance analysis than centers showing lower financial results. The conclusions point to the need for incorporating higher degree of analytical power in order to improve the tracking of strategic performance. This study is one of the first to concentrate in the area of strategic control.^

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Este trabajo explora una hipótesis: la experiencia política de los estudiantes universitarios vincula sus trayectorias personales con tres campos: la política partidaria, la política de las instituciones educativas y la lógica de constitución disciplinar

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Este trabajo explora una hipótesis: la experiencia política de los estudiantes universitarios vincula sus trayectorias personales con tres campos: la política partidaria, la política de las instituciones educativas y la lógica de constitución disciplinar

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Este trabajo explora una hipótesis: la experiencia política de los estudiantes universitarios vincula sus trayectorias personales con tres campos: la política partidaria, la política de las instituciones educativas y la lógica de constitución disciplinar

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CiaoPP is the abstract interpretation-based preprocessor of the Ciao multi-paradigm (Constraint) Logic Programming system. It uses modular, incremental abstract interpretation as a fundamental tool to obtain information about programs. In CiaoPP, the semantic approximations thus produced have been applied to perform high- and low-level optimizations during program compilation, including transformations such as múltiple abstract specialization, parallelization, partial evaluation, resource usage control, and program verification. More recently, novel and promising applications of such semantic approximations are being applied in the more general context of program development such as program verification. In this work, we describe our extensión of the system to incorpórate Abstraction-Carrying Code (ACC), a novel approach to mobile code safety. ACC follows the standard strategy of associating safety certificates to programs, originally proposed in Proof Carrying- Code. A distinguishing feature of ACC is that we use an abstraction (or abstract model) of the program computed by standard static analyzers as a certifícate. The validity of the abstraction on the consumer side is checked in a single-pass by a very efficient and specialized abstractinterpreter. We have implemented and benchmarked ACC within CiaoPP. The experimental results show that the checking phase is indeed faster than the proof generation phase, and that the sizes of certificates are reasonable. Moreover, the preprocessor is based on compile-time (and run-time) tools for the certification of CLP programs with resource consumption assurances.

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Abstract Due to recent scientific and technological advances in information sys¬tems, it is now possible to perform almost every application on a mobile device. The need to make sense of such devices more intelligent opens an opportunity to design data mining algorithm that are able to autonomous execute in local devices to provide the device with knowledge. The problem behind autonomous mining deals with the proper configuration of the algorithm to produce the most appropriate results. Contextual information together with resource information of the device have a strong impact on both the feasibility of a particu¬lar execution and on the production of the proper patterns. On the other hand, performance of the algorithm expressed in terms of efficacy and efficiency highly depends on the features of the dataset to be analyzed together with values of the parameters of a particular implementation of an algorithm. However, few existing approaches deal with autonomous configuration of data mining algorithms and in any case they do not deal with contextual or resources information. Both issues are of particular significance, in particular for social net¬works application. In fact, the widespread use of social networks and consequently the amount of information shared have made the need of modeling context in social application a priority. Also the resource consumption has a crucial role in such platforms as the users are using social networks mainly on their mobile devices. This PhD thesis addresses the aforementioned open issues, focusing on i) Analyzing the behavior of algorithms, ii) mapping contextual and resources information to find the most appropriate configuration iii) applying the model for the case of a social recommender. Four main contributions are presented: - The EE-Model: is able to predict the behavior of a data mining algorithm in terms of resource consumed and accuracy of the mining model it will obtain. - The SC-Mapper: maps a situation defined by the context and resource state to a data mining configuration. - SOMAR: is a social activity (event and informal ongoings) recommender for mobile devices. - D-SOMAR: is an evolution of SOMAR which incorporates the configurator in order to provide updated recommendations. Finally, the experimental validation of the proposed contributions using synthetic and real datasets allows us to achieve the objectives and answer the research questions proposed for this dissertation.

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The airport taxi planning (TP) module is a decision tool intended to guide airport surface management operations. TP is defined by a flow network optimization model that represents flight ground movements and improves aircraft taxiing routes and schedules during periods of aircraft congestion. TP is not intended to operate as a stand‐alone tool for airport operations management: on the contrary, it must be used in conjunction with existing departing and arriving traffic tools and overseen by the taxi planner of the airport, also known as the aircraft ground controller. TP must be flexible in order to accommodate changing inputs while maintaining consistent routes and schedules already delivered from past executions. Within this dynamic environment, the execution time of TP may not exceed a few minutes. Classic methods for solving binary multi‐commodity flow networks with side constraints are not efficient enough; therefore, a Lagrangian decomposition methodology has been adapted to solve it. We demonstrate TP Lagrangian decomposition using actual data from the Madrid‐Barajas Airport

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Aircraft Operators Companies (AOCs) are always willing to keep the cost of a flight as low as possible. These costs could be modelled using a function of the fuel consumption, time of flight and fixed cost (over flight cost, maintenance, etc.). These are strongly dependant on the atmospheric conditions, the presence of winds and the aircraft performance. For this reason, much research effort is being put in the development of numerical and graphical techniques for defining the optimal trajectory. This paper presents a different approach to accommodate AOCs preferences, adding value to their activities, through the development of a tool, called aircraft trajectory simulator. This tool is able to simulate the actual flight of an aircraft with the constraints imposed. The simulator is based on a point mass model of the aircraft. The aim of this paper is to evaluate 3DoF aircraft model errors with BADA data through real data from Flight Data Recorder FDR. Therefore, to validate the proposed simulation tool a comparative analysis of the state variables vector is made between an actual flight and the same flight using the simulator. Finally, an example of a cruise phase is presented, where a conventional levelled flight is compared with a continuous climb flight. The comparison results show the potential benefits of following user-preferred routes for commercial flights.

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Disruptions in tokamaks devices are unavoidable, and they can have a significant impact on machine integrity. So it is very important have mechanisms to predict this phenomenon. Disruption prediction is a very complex task, not only because it is a multi-dimensional problem, but also because in order to be effective, it has to detect well in advance the actual disruptive event, in order to be able to use successful mitigation strategies. With these constraints in mind a real-time disruption predictor has been developed to be used in JET tokamak. The predictor has been designed to run in the Multithreaded Application Real-Time executor (MARTe) framework. The predictor ?Advanced Predictor Of DISruptions? (APODIS) is based on Support Vector Machine (SVM).

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Knowledge about the quality characteristics (QoS) of service com- positions is crucial for determining their usability and economic value. Ser- vice quality is usually regulated using Service Level Agreements (SLA). While end-to-end SLAs are well suited for request-reply interactions, more complex, decentralized, multiparticipant compositions (service choreographies) typ- ically involve multiple message exchanges between stateful parties and the corresponding SLAs thus encompass several cooperating parties with interde- pendent QoS. The usual approaches to determining QoS ranges structurally (which are by construction easily composable) are not applicable in this sce- nario. Additionally, the intervening SLAs may depend on the exchanged data. We present an approach to data-aware QoS assurance in choreographies through the automatic derivation of composable QoS models from partici- pant descriptions. Such models are based on a message typing system with size constraints and are derived using abstract interpretation. The models ob- tained have multiple uses including run-time prediction, adaptive participant selection, or design-time compliance checking. We also present an experimen- tal evaluation and discuss the benefits of the proposed approach.

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Although numerous modelling efforts have integrated food and water considerations at the farm or river basin level, very few agro-economic models are able to jointly assess water and food policies at the global level. The present report explores the feasibility of integrating water considerations into the CAPRI model. First, a literature review of modelling approaches integrating food and water issues has been conducted. Three agro-economic models, IMPACT, WATERSIM and GLOBIOM, have been analysed in detail. In addition, biophysical and hydrological models estimating agricultural water use have also been studied, in particular the global hydrological model WATERGAP and the LISFLOOD model. Thanks to the programming approach of its supply module, CAPRI shows a high potentiality to integrate environmental indicators as well as to enter new resource constraints (land potentially irrigated, irrigation water) and input-output relationships. At least in theory, the activity-based approach of the regional programming model in CAPRI allows differentiating between rainfed and irrigated activities. The suggested approach to include water into the CAPRI model involves creating an irrigation module and a water use module. The development of the CAPRI water module will enable to provide scientific assessment on agricultural water use within the EU and to analyze agricultural pressures on water resources. The feasibility of the approach has been tested in a pilot case study including two NUTS 2 regions (Andalucia in Spain and Midi-Pyrenees in France). Preliminary results are presented, highlighting the interrelations between water and agricultural developments in Europe. As a next step, it is foreseen to further develop the CAPRI water module to account for competition between agricultural and non-agricultural water use. This will imply building a water use sub-module to compute water use balances.

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Podemos definir la sociedad como un sistema complejo que emerge de la cooperación y coordinación de billones de individuos y centenares de países. En este sentido no vivimos en una isla sino que estamos integrados en redes sociales que influyen en nuestro comportamiento. En esta tesis doctoral, presentamos un modelo analítico y una serie de estudios empíricos en los que analizamos distintos procesos sociales dinámicos desde una perspectiva de la teoría de redes complejas. En primer lugar, introducimos un modelo para explorar el impacto que las redes sociales en las que vivimos inmersos tienen en la actividad económica que transcurre sobre ellas, y mas concretamente en hasta qué punto la estructura de estas redes puede limitar la meritocracia de una sociedad. Como concepto contrario a meritocracia, en esta tesis, introducimos el término topocracia. Definimos un sistema como topocrático cuando la influencia o el poder y los ingresos de los individuos vienen principalmente determinados por la posición que ocupan en la red. Nuestro modelo es perfectamente meritocrático para redes completamente conectadas (todos los nodos están enlazados con el resto de nodos). Sin embargo nuestro modelo predice una transición hacia la topocracia a medida que disminuye la densidad de la red, siendo las redes poco densascomo las de la sociedad- topocráticas. En este modelo, los individuos por un lado producen y venden contenidos, pero por otro lado también distribuyen los contenidos producidos por otros individuos mediando entre comprador y vendedor. La producción y distribución de contenidos definen dos medios por los que los individuos reciben ingresos. El primero de ellos es meritocrático, ya que los individuos ingresan de acuerdo a lo que producen. Por el contrario el segundo es topocrático, ya que los individuos son compensados de acuerdo al número de cadenas mas cortas de la red que pasan a través de ellos. En esta tesis resolvemos el modelo computacional y analíticamente. Los resultados indican que un sistema es meritocrático solamente si la conectividad media de los individuos es mayor que una raíz del número de individuos que hay en el sistema. Por tanto, a la luz de nuestros resultados la estructura de la red social puede representar una limitación para la meritocracia de una sociedad. En la segunda parte de esta tesis se presentan una serie de estudios empíricos en los que se analizan datos extraídos de la red social Twitter para caracterizar y modelar el comportamiento humano. En particular, nos centramos en analizar conversaciones políticas, como las que tienen lugar durante campañas electorales. Nuestros resultados indican que la atención colectiva está distribuida de una forma muy heterogénea, con una minoría de cuentas extremadamente influyente. Además, la capacidad de los individuos para diseminar información en Twitter está limitada por la estructura y la posición que ocupan en la red de seguidores. Por tanto, de acuerdo a nuestras observaciones las redes sociales de Internet no posibilitan que la mayoría sea escuchada por la mayoría. De hecho, nuestros resultados implican que Twitter es topocrático, ya que únicamente una minoría de cuentas ubicadas en posiciones privilegiadas en la red de seguidores consiguen que sus mensajes se expandan por toda la red social. En conversaciones políticas, esta minoría de cuentas influyentes se compone principalmente de políticos y medios de comunicación. Los políticos son los mas mencionados ya que la gente les dirige y se refiere a ellos en sus tweets. Mientras que los medios de comunicación son las fuentes desde las que la gente propaga información. En un mundo en el que los datos personales quedan registrados y son cada día mas abundantes y precisos, los resultados del modelo presentado en esta tesis pueden ser usados para fomentar medidas que promuevan la meritocracia. Además, los resultados de los estudios empíricos sobre Twitter que se presentan en la segunda parte de esta tesis son de vital importancia para entender la nueva "sociedad digital" que emerge. En concreto hemos presentado resultados relevantes que caracterizan el comportamiento humano en Internet y que pueden ser usados para crear futuros modelos. Abstract Society can be defined as a complex system that emerges from the cooperation and coordination of billions of individuals and hundreds of countries. Thus, we do not live in social vacuum and the social networks in which we are embedded inevitably shapes our behavior. Here, we present an analytical model and several empirical studies in which we analyze dynamical social systems through a network science perspective. First, we introduce a model to explore how the structure of the social networks underlying society can limit the meritocracy of the economies. Conversely to meritocracy, in this work we introduce the term topocracy. We say that a system is topocratic if the compensation and power available to an individual is determined primarily by her position in a network. Our model is perfectly meritocratic for fully connected networks but becomes topocratic for sparse networks-like the ones in society. In the model, individuals produce and sell content, but also distribute the content produced by others when they belong to the shortest path connecting a buyer and a seller. The production and distribution of content defines two channels of compensation: a meritocratic channel, where individuals are compensated for the content they produce, and a topocratic channel, where individual compensation is based on the number of shortest paths that go through them in the network. We solve the model analytically and show that the distribution of payoffs is meritocratic only if the average degree of the nodes is larger than a root of the total number of nodes. Hence, in the light of our model, the sparsity and structure of networks represents a fundamental constraint to the meritocracy of societies. Next, we present several empirical studies that use data gathered from Twitter to analyze online human behavioral patterns. In particular, we focus on political conversations such as electoral campaigns. We found that the collective attention is highly heterogeneously distributed, as there is a minority of extremely influential accounts. In fact, the ability of individuals to propagate messages or ideas through the platform is constrained by the structure of the follower network underlying the social media and the position they occupy on it. Hence, although people have argued that social media can allow more voices to be heard, our results suggest that Twitter is highly topocratic, as only the minority of well positioned users are widely heard. This minority of influential accounts belong mostly to politicians and traditional media. Politicians tend to be the most mentioned, while media are the sources of information from which people propagate messages. We also propose a methodology to study and measure the emergence of political polarization from social interactions. To this end, we first propose a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we illustrate our methodology by applying it to Twitter data. In a world where personal data is increasingly available, the results of the analytical model introduced in this work can be used to enhance meritocracy and promote policies that help to build more meritocratic societies. Moreover, the results obtained in the latter part, where we have analyzed Twitter, are key to understand the new data-driven society that is emerging. In particular, we have presented relevant information that can be used to benchmark future models for online communication systems or can be used as empirical rules characterizing our online behavior.

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Changes in the roles of the government and the private sector in the provision of public services along with budget constraints are resulting in an increasing use of the concession approach for financing and managing roads. In the last few years, many of these contracts set up incentives linked to bonuses to encourage the concessionaire to render a better service to the users. Road safety is one the aspects on the basis of which concessionaires can be rewarded according to their performance. The goal of this paper is to evaluate whether road safety incentives are being defined in the right way nowadays in different European countries and also identify what incentives would need to be implemented to achieve a socially optimal road safety level. To that end, we develop a specific incentive for road concession contracts that encourages companies to achieve the optimal level. We apply this methodology to three case studies of concessions recently awarded in order to determine to what extend the incentives they set up are closer or farther to the optimum.

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En su proceso de crecimiento, las ciudades de América Latina y el Caribe (ALC) han tenido una vinculación histórica con la dinámica de implementación de herramientas, metodologías y proyectos urbanos, gestados en otros contextos, especialmente desde Europa (UE) y Estados Unidos (EE.UU). Desde la época colonial hasta hoy, la mayor parte de las ciudades de ALC han experimentado diversos tipos de influencia urbana externa, que han dejado huellas tangibles. Esta influencia ha ido variando a través de los años, desde la implantación directa de un modelo urbano, propia de la época colonial; hasta la importación de modelos urbanos total o parcialmente, de manera autónoma y ajena al origen de este. Actualmente, en ALC se han generado diversas iniciativas para abordar las necesidades urbanas desde sus especificidades, pero los instrumentos y proyectos vanguardistas utilizados en países desarrollados, siguen teniendo mayor fuerza de atracción y diseminación que las iniciativas vecinas. Se observa que las ciudades intermedias, que crecen con mayor velocidad que las grandes ciudades, también participan activamente en este proceso, aunque con otras limitaciones y condicionantes, diferentes a las encontradas en las grandes ciudades de la Región. ¿Por qué se produce esta dinámica?, ¿quiénes participan?, ¿cuáles son sus procesos?, ¿responden a las necesidades del complejo y diverso contexto urbano latinoamericano? Las Ciudades Intermedias Latinoamericanas ante los Modelos Urbanos Externos, es una investigación que aborda la dinámica de implementación de modelos de desarrollo urbanos1 exógenos, en ciudades emergentes que, en su proceso de crecimiento, tienden a repetir patrones de las grandes ciudades, y que en sí mismas, representan una oportunidad ante los desequilibrios territoriales de ALC. Esta dinámica, ha sido abordada por investigadores de diversas disciplinas, cuyos puntos de vista en muchas ocasiones no coinciden, pero revelan que estamos frente a una discusión de larga data, entre las visiones modernistas y las visiones identitarias de la historia urbana de ALC. Por ello, el trabajo recoge la evolución de los procesos de toma de decisiones, desarrollados bajo un efecto cascada (Global, Internacional, Regional, Nacional, Subnacional, Local), donde actualmente el nivel Local asciende a espacios del nivel Regional (ALC) e Internacional; pasando de meros receptores de políticas generadas en un plano superior derivadas de las relaciones geopolíticas y geoeconómicas de escala mundial; a ser sujetos proactivos del desarrollo de sus territorios. Para observar la concatenación de este proceso macro-disciplinar-micro (grosso modo), se plantea una herramienta metodológica de triangulación, desde la que se pueda visualizar el contexto en el que se produce la dinámica y como éste la condiciona. Con dicha metodología se abordará ALC como caso de estudio general, haciendo una aproximación al detalle en dos casos particulares: Ciudad Guayana (República Bolivariana de Venezuela) y Santiago de los Caballeros (República Dominicana). Estos casos, sumados a las observaciones de actores vinculados a la dinámica de transferencia de modelos urbanos, coadyuvarán en este esfuerzo de aproximación, para definir con más claridad un proceso que se incrementa y complejiza, en medio de la denominada “era de las ciudades”. ABSTRACT In its growth process, the cities of Latin America and the Caribbean (LAC) have had a historical link with the dynamics of implementation tools and engendered in other contexts, especially from Europe (EU) and the US methodologies (USA). From colonial times until today, most LAC cities have experienced various types of external urban influence that have left tangible traces. This influence has varied over the years, since the introduction of direct, typical of the colonial era; to import all or part independently and outside the origin of this urban model. Currently, in LAC they have generated various initiatives to address urban needs from its specificities, but notes that the instruments used in cutting-edge projects and developed countries, are still more attractive force and spread to neighboring initiatives. It is observed that the intermediate cities, which grow faster than big cities are also actively involved in this process, although with different constraints and other limitations to the big cities of the region. Why this dynamic occurs?, Who ?, which involved processes are ?, respond to the needs of complex and diverse Latin American urban context? Intermediate Latin American cities to external urban models, is a research that addresses the dynamics of exogenous implementation of urban development models in emerging cities in their growth process, they tend to repeat patterns of large cities, and represent a shot at LAC regional imbalances. This dynamic has been addressed by researchers from various disciplines, whose views often do not match, but show that we are facing a long-standing debate between modernists and identity visions on urban history of ALC. Therefore, the work shows the evolution of the processes of decision making, developed under a (global, international, regional, national, subnational, local) cascade effect, which currently stands at the Local level Regional level spaces (ALC) and International, from mere recipients of policies generated on a higher plane derived from the geopolitical and geo-economic relations worldwide; to be proactive in the development of their territories subject. To observe this process concatenation macro-micro-discipline (roughly), a triangulation methodology tool, from which it can view the context in which the dynamic occurs and how it affects what arises. ALC will address her as if general study, making an approach to detail two particular cases: Ciudad Guayana (Bolivarian Republic of Venezuela) and Santiago de los Caballeros (Dominican Republic). These cases, together with the comments of stakeholders involved in the dynamics of transfer of urban models, will assist in this effort approach to define more clearly a process that increases and more complex, amid the so-called "era of the cities".

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O presente trabalho tem como tema central a opinião do surdo universitário sobre sua auto- estima e qualidade vida. Os objetivos foram conhecer o joven-adulto surdo universitário, segundo sua opinião, buscando especificamente identificar os fatores que contribuíram para o seu desenvolvimento psicológico e sua auto-estima; e identificar as características da qualidade de vida, considerando os aspectos físico, psicológico, relações sociais e meio ambiente. Participaram desta pesquisa 3 jovens-adultos surdos, universitários. O método utilizado foi o descritivo qualitativo, usando-se como fonte de coleta de dados a entrevista livre e o WHOQOL-bref. O método qualitativo na área da saúde visa investigar o significado que os fenômenos sentimentos, idéias, vivências, manifestações, dentre outros, tem para as pessoas e que dão molde às suas vidas incluindo os cuidados com a saúde. Percebemos que ao atingirem a fase adulta, os sujeitos pesquisados conseguem tomar decisões e escolher seus caminhos com maior liberdade em função das experiências e condições que lhes foram apresentadas. Verificamos que as situações vividas no ambiente escolar e o aprendizado da língua de sinais contribuíram para sua constituição como sujeito não limitado à condição da surdez. Foi possível identificar que possuem expectativas profissionais futuras e expressaram suas dificuldades, desejos, frustrações diante do mercado de trabalho, relações sociais e familiares como qualquer outro individuo, encontrando recursos internos para o enfrentamento das circunstâncias cotidianas. Os resultados da pesquisa também permitiram observar que os surdos reconhecem o grau de satisfação que têm com a vida, seu estado de saúde e cuidados com seu bem-estar físico, psicológico e social. Concluímos que ao recontar sua história de vida os surdos têm a possibilidade de se reconhecer como sujeitos e a oportunidade de dar continuidade às próprias vivências que contribuíram para seu bem-estar