4,470 research outputs found
Risk Perceptions of Hurricane Track Forecasts
Previous research has suggested that misinterpretations of hurricane track forecasts can lead to errors in estimation of perceived risk. One factor that can be used to understand these errors in judgment of risk perception is called optimistic bias, in which an individual perceives that compared to another person they are at less risk. Thus, the purpose of this study was to examine how risk perceptions of hurricane track forecasts are influenced by the optimistic bias and changes in the forecasts. Students from three coastal universities took a survey regarding hurricane risk from two different track scenarios of a hypothetical hurricane approaching their university. Results indicated that optimism and perceptions of hurricane tracks were not correlated. Regardless of changes in forecast tracks, students perceived the same level of risk by the final forecast. This research has important social implications because hurricane track forecasts are part of the hurricane decision-making process
Risk Perceptions of Hurricane Track Forecasts
Previous research has suggested that misinterpretations of hurricane track forecasts can lead to errors in estimation of perceived risk. One factor that can be used to understand these errors in judgment of risk perception is called optimistic bias, in which an individual perceives that compared to another person they are at less risk. Thus, the purpose of this study was to examine how risk perceptions of hurricane track forecasts are influenced by the optimistic bias and changes in the forecasts. Students from three coastal universities took a survey regarding hurricane risk from two different track scenarios of a hypothetical hurricane approaching their university. Results indicated that optimism and perceptions of hurricane tracks were not correlated. Regardless of changes in forecast tracks, students perceived the same level of risk by the final forecast. This research has important social implications because hurricane track forecasts are part of the hurricane decision-making process
Sobre la iconografía de San Cirilo de Alejandría en el concilio de Éfeso de Francisco Meneses Osorio
La pintura de Francisco Meneses Osorio representa de forma emblemática el Concilio de Éfeso del 431 en el que Cirilo de Alejandría fue protagonista principal. En este concilio se enfrentaron dos bandos, el de Cirilo que defendía la denominación de María como Theotokos o Madre de Dios y los de Nestorio que prefería llamarla Madre de Cristo, triunfando el patriarca de Alejandría. Pero el tema principal no es teológico sino una defensa de la antigüedad de la Orden del Carmen que había sido duramente discutida durante todo el siglo XVII, en la que negaba la pertenencia de Cirilo de Alejandría a la misma.The painting of Francisco Meneses Osorio represents in emblematic form the Council at Ephesus in 431 in which Cyril of Alexandria was the main protagonist. In this council faced two sides, the one of Cyril that defended the denomination of Mary like Theotokos or Mother of God and those of Nestorius whom they preferred to call her Mother of Christ, prevailing the patriarch of Alexandria. But the main subject is not theological but a defence of the antiquity of the order of the Carmelo that hard had been discussed 17th century throughout, in that denied the property of Cyril from Alexandria to the same one
Incorporating boundary conditions in a stochastic volatility model for the numerical approximation of bond prices
Producción CientíficaIn this paper, we consider a two-factor interest rate model with stochastic volatil-ity, and we assume that the instantaneous interest rate follows a jump-diffusionprocess. In this kind of problems, a two-dimensional partial integro-differentialequation is derived for the values of zero-coupon bonds. To apply standardnumerical methods to this equation, it is customary to consider a boundeddomain and incorporate suitable boundary conditions. However, for thesetwo-dimensional interest rate models, there are not well-known boundary con-ditions, in general. Here, in order to approximate bond prices, we propose newboundary conditions, which maintain the discount function property of thezero-coupon bond price. Then, we illustrate the numerical approximation ofthe corresponding boundary value problem by means of an alternative directionimplicit method, which has been already applied for pricing options. We testthese boundary conditions with several interest rate pricing models.MEC-FEDER Grant MTM2017-85476-C2-P, Junta de Castilla y León Regional Grants VA041P17 (with European FEDERFunds), VA138G18 y VA148G1
Improving the Computational Efficiency in Symmetrical Numeric Constraint Satisfaction Problems
Models are used in science and engineering for experimentation,
analysis, diagnosis or design. In some cases, they can be considered
as numeric constraint satisfaction problems (NCSP). Many models
are symmetrical NCSP. The consideration of symmetries ensures that
NCSP-solver will find solutions if they exist on a smaller search space.
Our work proposes a strategy to perform it. We transform the symmetrical
NCSP into a newNCSP by means of addition of symmetry-breaking
constraints before the search begins. The specification of a library of possible
symmetries for numeric constraints allows an easy choice of these
new constraints. The summarized results of the studied cases show the
suitability of the symmetry-breaking constraints to improve the solving
process of certain types of symmetrical NCSP. Their possible speedup
facilitates the application of modelling and solving larger and more
realistic problems.Ministerio de Ciencia y Tecnología DIP2003-0666-02-
A Topological-Based Method for Allocating Sensors by Using CSP Techniques
Model-based diagnosis enables isolation of faults of a system.
The diagnosis process uses a set of sensors (observations) and a model
of the system in order to explain a wrong behaviour. In this work, a
new approach is proposed with the aim of improving the computational
complexity for isolating faults in a system. The key idea is the addition of
a set of new sensors which allows the improvement of the diagnosability
of the system. The methodology is based on constraint programming
and a greedy method for improving the computational complexity of the
CSP resolution. Our approach maintains the requirements of the user
(detectability, diagnosability,. . .).Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
An Integration of FDI and DX Techniques for Determining the Minimal Diagnosis in an Automatic Way
Two communities work in parallel in model-based diagnosis:
FDI and DX. In this work an integration of the FDI and the DX communities
is proposed. Only relevant information for the identification of the
minimal diagnosis is used. In the first step, the system is divided into
clusters of components, and each cluster is separated into nodes. The
minimal and necessary set of contexts is then obtained for each cluster.
These two steps automatically reduce the computational complexity
since only the essential contexts are generated. In the last step, a signature
matrix and a set of rules are used in order to obtain the minimal
diagnosis. The evaluation of the signature matrix is on-line, the rest of
the process is totally off-line.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Diagnosing Errors in DbC Programs Using Constraint Programming
Model-Based Diagnosis allows to determine why a correctly
designed system does not work as it was expected. In this paper, we propose
a methodology for software diagnosis which is based on the combination
of Design by Contract, Model-Based Diagnosis and Constraint
Programming. The contracts are specified by assertions embedded in the
source code. These assertions and an abstraction of the source code are
transformed into constraints, in order to obtain the model of the system.
Afterwards, a goal function is created for detecting which assertions or
source code statements are incorrect. The application of this methodology
is automatic and is based on Constraint Programming techniques.
The originality of this work stems from the transformation of contracts
and source code into constraints, in order to determine which assertions
and source code statements are not consistent with the specification.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
Combining Heuristics in Assembly Sequence Planning
Assembly Sequence Planning is tackled by modelling and solving a
planning problem that considers the execution of the plan in a system with multiple
assembly machines. The objective of the plan is the minimization of the total
assembly time (makespan). To meet this objective, the model takes into account the
durations and resources for the assembly tasks, the change of configuration in the
machines, and the transportation of intermediate subassemblies between different
workstations. In order to solve the problem, different heuristics has been defined
from two relaxed model of it, one considering only the precedence constraints among
tasks, and the other one considering only the use of shared resources. From these
basic heuristics, other ones have been defined, combining both types of information
from the problem, so that the refinement produces substantial improvements over the
initial heuristics.Ministerio de Ciencia y TecnologíaDPI2003-07146-C02-0
Distributed Model-Based Diagnosis using Object-Relational Constraint Databases
This work presents a proposal to diagnose distributed
systems utilizing model-based diagnosis using distributed
databases. In order to improve aspects as versatility, persistence,
easy composition and efficiency in the diagnosis
process we use an Object Relational Constraint Database
(ORCDB). Thereby we define a distributed architecture to
store the behaviour of components as constraints in a relational
database to diagnose a distributed system. This
work proposes an algorithm to detect which components fail
when their information is distributed in several databases,
and all the information is not available in a global way. It
is also offered a proposal to define, in execution time, the
allocation of the sensors in a distributed system.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0
- …