439 research outputs found
Diagnostic reasoning techniques for selective monitoring
An architecture for using diagnostic reasoning techniques in selective monitoring is presented. Given the sensor readings and a model of the physical system, a number of assertions are generated and expressed as Boolean equations. The resulting system of Boolean equations is solved symbolically. Using a priori probabilities of component failure and Bayes' rule, revised probabilities of failure can be computed. These will indicate what components have failed or are the most likely to have failed. This approach is suitable for systems that are well understood and for which the correctness of the assertions can be guaranteed. Also, the system must be such that changes are slow enough to allow the computation
Re-Solving Stochastic Programming Models for Airline Revenue Management
We study some mathematical programming formulations for the origin-destination model in airline revenue management. In particular, we focus on the traditional probabilistic model proposed in the literature. The approach we study consists of solving a sequence of two-stage stochastic programs with simple recourse, which can be viewed as an approximation to a multi-stage stochastic programming formulation to the seat allocation problem. Our theoretical results show that the proposed approximation is robust, in the sense that solving more successive two-stage programs can never worsen the expected revenue obtained with the corresponding allocation policy. Although intuitive, such a property is known not to hold for the traditional deterministic linear programming model found in the literature. We also show that this property does not hold for some bid-price policies. In addition, we propose a heuristic method to choose the re-solving points, rather than re-solving at equally spaced times as customary. Numerical results are presented to illustrate the effectiveness of the proposed approach
On Selecting and Scheduling Assembly Plans Using Constraint Programming
This work presents the application of Constraint
Programming to the problem of selecting and sequencing assembly
operations. The set of all feasible assembly plans for a single product is
represented using an And/Or graph. This representation embodies some
of the constraints involved in the planning problem, such as precedence
of tasks, and the constraints due to the completion of a correct assembly
plan. The work is focused on the selection of tasks and their optimal
ordering, taking into account their execution in a generic multi-robot
system. In order to include all different constraints of the problem, the
And/Or graph representation is extended, so that links between nodes
corresponding to assembly tasks are added, taking into account the
resource constraints. The resultant problem is mapped to a Constraint
Satisfaction Problem (CSP), and is solved using Constraint
Programming, a powerful programming paradigm that is increasingly
used to model and solve many hard real-life problems
A Pomset-Based Model for Estimating Workcells' Setups in Assembly Sequence Planning
This paper presents a model based on pomsets (partially ordered multisets)
for estimating the minimum number of setups in the workcells in Assembly
Sequence Planning. This problem is focused through the minimization of
the makespan (total assembly time) in a multirobot system. The planning model
considers, apart from the durations and resources needed for the assembly tasks,
the delays due to the setups in the workcells. An A* algorithm is used to meet
the optimal solution. It uses the And/Or graph for the product to assemble, that
corresponds to a compressed representation of all feasible assembly plans. Two
basic admissible heuristic functions can be defined from relaxed models of the
problem, considering the precedence constraints and the use of resources separately.
The pomset-based model presented in this paper takes into account the
precedence constraints in order to obtain a better estimation for the second heuristic
function, so that the performance of the algorithm could be improved
Task planning and control synthesis for robotic manipulation in space applications
Space-based robotic systems for diagnosis, repair and assembly of systems will require new techniques of planning and manipulation to accomplish these complex tasks. Results of work in assembly task representation, discrete task planning, and control synthesis which provide a design environment for flexible assembly systems in manufacturing applications, and which extend to planning of manipulatiuon operations in unstructured environments are summarized. Assembly planning is carried out using the AND/OR graph representation which encompasses all possible partial orders of operations and may be used to plan assembly sequences. Discrete task planning uses the configuration map which facilitates search over a space of discrete operations parameters in sequential operations in order to achieve required goals in the space of bounded configuration sets
A modernização de Santos no século XIX: mudanças espaciais e da sociabilidade urbana no centro velho
Santos' growth, as occurred on other Brazilian cities at the end of the 19th century, was associated with transformations experimented throughout the country. These transformations sought to place a landmark on capitalism development on Brazil, through the economic model and through the assimilation of values, patterns and ways of life. The elite's fixation on urban centers collaborated to the development of services' network and urban enhancements. In a larger proportion, it was financed by foreign capital. Aiming to show, starting from the current transformations, how it formed the modern Santos city, considering the urban space and the sociability issues. Santos was built on the shades of the bourgeois and capitalist society, whose values and ways of life would lead to urban interventions throughout the 20th century.O crescimento de Santos, assim como o de outras cidades brasileiras no final do século XIX, esteve associado às transformações do país que buscava se inserir nos marcos internacionais do desenvolvimento do capitalismo, tanto em relação ao modelo econômico, quanto pela assimilação de valores, padrões e modos de vida europeizados. A fixação das elites em centros urbanos concorreu para a montagem de uma rede de serviços e melhoramentos urbanos que foram, em larga medida, financiados pelo capital estrangeiro. Pretendemos analisar, a partir das transformações em curso, tanto do ponto de vista espacial, quanto da sociabilidade urbana, como se formava naquele momento aquela que pode ser vista como a Santos moderna, constituída nos marcos do desenvolvimento da sociedade burguesa e capitalista, cujos valores e modos de vida viriam a orientar as intervenções urbanísticas ao longo do século XX
A importância e influência do trademarketing na decisão de compra dos consumidores: o caso das farmácias portuguesas
No âmbito do tema trade marketing, a presente dissertação tem como objetivo geral identificar e caracterizar de que forma o trade marketing influência a decisão de compra dos consumidores no ponto de venda, no caso concreto das farmácias portuguesas. Prende-se demonstrar a importância do ponto de venda e do investimento no mesmo, verificar a importância de um Key Account Manager, evidenciar os fatores externos que mais influenciam a decisão de compra, comprovar a influência dos farmacêuticos na decisão de compra e identificar as ações e materiais que mais influenciam a decisão de compra. A investigação foi conduzida junto de um grupo de especialistas através do método delphi a partir do qual foi possível evidenciar a importância do trade marketing e a influência que este provoca. Os resultados revelaram que o trade marketing influência cada vez mais a decisão de compra dos consumidores e que o investimento das marcas no futuro deve ser feito no ponto de venda. Foi assim possível concluir que o investimento das marcas no futuro deve ser feito no ponto de venda através do trade marketing uma vez que foi comprovado que as ações e materiais desenvolvidos pelo mesmo são os principais influenciadores da decisão de compra
A utilização do Quadro Interactivo Multimédia nas disciplinas de Português e Espanhol e o seu impacto na motivação dos alunos do Ensino Básico
O presente relatório visa, numa primeira parte, dar a conhecer o processo de integração do Quadro Interativo Multimédia (QIM) nas escolas portuguesas, destacando, para tal, o contributo do Plano de Educação Tecnológica, quer no aumento da rede de infraestruturas, quer na formação de professores e criação de recursos educativos digitais (RED). Apresentando as potencialidades desta ferramenta educativa, avaliam-se as vantagens, desvantagens e o impacto da sua utilização na motivação e aprendizagem dos estudantes, segundo a mais recente literatura. Abordam-se diferentes utilizações do
QIM nas aulas de Português, em particular o ensino da gramática através deste recurso, e nas aulas de Espanhol/LE, através da exploração de pequenas unidades didáticas interativas concebidas especificamente para o QIM. Numa segunda parte, apresenta-se o Colégio Sra. da Boa Nova, onde foi realizada a Prática de Ensino Supervisionada (PES) e uma caracterização das turmas em que foram lecionadas as aulas práticas de Português e de Espanhol/LE. Por fim, apresentam-se as atividades que foram desenvolvidas, em particular com o QIM, durante a lecionação
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