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81.
This paper shows how to apply discrete time non-homogeneous semi-Markov processes (DTNHSMP) with an age index to credit risk.
The idea is to consider the credit risk problem as a reliability model indexed by the age and in this way, many semi-Markov
results could be adapted to describe credit risk problem. The default state is seen as a “non working state”. As the semi-Markov
process is a generalization of Markov process, the presented model can be seen as a more general migration model. In fact,
in semi-Markov environment the distribution function (d.f.) of the waiting time before a transition can be of any type and
without the strong constraints of the Markov model. Furthermore, some results on the asymptotic behavior of the presented
model are given. This permits the construction of the d.f. of the default random variable for each “working state”. An example,
constructed manipulating some Standard & Poor’s (S&P) data, is presented. 相似文献
82.
QUAD: A multivariate stream cipher with provable security 总被引:1,自引:0,他引:1
83.
Samuel Aupetit Virginie Gallier Jacques Riff Stéphane Espié Flavien Delgehier 《Ergonomics》2016,59(8):1109-1120
This article sets out to identify the typical risky situations experienced by novice motorcyclists in the real world just after licensing. The procedure consists of a follow-up of six novices during their first two months of riding with their own motorbike instrumented with cameras. The novices completed logbooks on a daily basis in order to identify the risky situations they encountered, and were given face-to-face interviews to identify the context and their shortcomings during the reported events. Data show a large number of road configurations considered as risky by the riders (248 occurrences), especially during the first two weeks. The results revealed that a lack of hazard perception skills contributed to the majority of these incidents. These situations were grouped together to form clusters of typical incident scenarios on the basis of their similarities. The most frequent scenario corresponds to a lane change in dense traffic (15% of all incidents). The discussion shows how this has enhanced our understanding of novice riders’ behaviour and how the findings can improve training and licensing. Lastly, the main methodological limitations of the study and some guidelines for improving future naturalistic riding studies are presented.
Practitioner Summary:
This article aims to identify the risky situations of novice motorcyclists in real roads. Two hundred forty-eight events were recorded and 13 incident scenarios identified. Results revealed that a lack of hazard perception contributed to the majority of these events. The most frequent scenario corresponds to a lane change in dense traffic. 相似文献
84.
Hendriks Martijn Verriet Jacques Basten Twan Theelen Bart Brassé Marco Somers Lou 《International Journal on Software Tools for Technology Transfer (STTT)》2017,19(4):487-510
International Journal on Software Tools for Technology Transfer - System designers make trade-offs between metrics of interest such as execution time, functional quality and cost to create a... 相似文献
85.
Transfer of learning in virtual environments: a new challenge? 总被引:1,自引:0,他引:1
The aim of all education is to apply what we learn in different contexts and to recognise and extend this learning to new
situations. Virtual learning environments can be used to build skills. Recent research in cognitive psychology and education
has shown that acquisitions are linked to the initial context. This provides a challenge for virtual reality in education
or training. A brief overview of transfer issues highlights five main ideas: (1) the type of transfer enables the virtual
environment (VE) to be classified according to what is learned; (2) the transfer process can create conditions within the
VE to facilitate transfer of learning; (3) specific features of VR must match and comply with transfer of learning; (4) transfer
can be used to assess a VE’s effectiveness; and (5) future research on transfer of learning must examine the singular context
of learning. This paper discusses how new perspectives in cognitive psychology influence and promote transfer of learning
through the use of VEs. 相似文献
86.
Towards a continuous microfluidic rheometer 总被引:1,自引:1,他引:0
Pierre Guillot Thomas Moulin Roman Kötitz Matthieu Guirardel Arash Dodge Mathieu Joanicot Annie Colin Charles-Henri Bruneau Thierry Colin 《Microfluidics and nanofluidics》2008,5(5):619-630
In a previous paper we presented a way to measure the rheological properties of complex fluids on a microfluidic chip (Guillot
et al., Langmuir 22:6438, 2006). The principle of our method is to use parallel flows between two immiscible fluids as a pressure
sensor. In fact, in a such flow, both fluids flow side by side and the size occupied by each fluid stream depends only on
both flow rates and on both viscosities. We use this property to measure the viscosity of one fluid knowing the viscosity
of the other one, both flow rates and the relative size of both streams in a cross-section. We showed that using a less viscous
fluid as a reference fluid allows to define a mean shear rate with a low standard deviation in the other fluid. This method
allows us to measure the flow curve of a fluid with less than 250 μL of fluid. In this paper we implement this principle in
a fully automated set up which controls the flow rate, analyzes the picture and calculates the mean shear rate and the viscosity
of the studied fluid. We present results obtained for Newtonian fluids and complex fluids using this set up and we compare
our data with cone and plate rheometer measurements. By adding a mixing stage in the fluidic network we show how this set
up can be used to characterize in a continuous way the evolution of the rheological properties as a function of the formulation
composition. We illustrate this by measuring the rheological curve of four formulations of polyethylene oxide solution with
only 1.3 mL of concentrated polyethylene oxide solution. This method could be very useful in screening processes where the
viscosity range and the behavior of the fluid to an applied stress must be evaluated. 相似文献
87.
Jacques Dubrois 《Information Processing Letters》2006,97(2):41-45
E. Bach, following an idea of T. Itoh, has shown how to build a small set of numbers modulo a prime p such that at least one element of this set is a generator of Z/pZ. E. Bach suggests also that at least half of his set should be generators. We show here that a slight variant of this set can indeed be made to contain a ratio of primitive roots as close to 1 as necessary. In particular we present an asymptotically algorithm providing primitive roots of p with probability of correctness greater than 1−? and several O(logα(p)), α?5.23, algorithms computing “Industrial-strength” primitive roots. 相似文献
88.
89.
Quality control lead times are one of most significant causes of loss of time in the pharmaceutical and cosmetics industries. This is partly due to the organization of laboratories that feature parallel multipurpose machines for chromatographic analyses. The testing process requires long setup times and operators are needed to launch the process. The various controls are non-preemptive and are characterized by a release date, a due date and available routings. These quality processes lead to significant delays, and we therefore evaluate the total tardiness criterion. Previous heuristics were defined for the total tardiness criterion, parallel machines, and setup such as apparent tardiness cost (ATC) and ATC with setups (ATCS). We propose new rules and a simulated annealing procedure in order to minimize total tardiness. 相似文献
90.
Olivier Noel Houssein Awada Gilles Castelein Maurice Brogly Jacques Schultz 《The Journal of Adhesion》2006,82(7):649-669
The atomic force microscope (AFM) can be used to perform surface force measurements in the quasi-static mode (cantilever is not oscillating) to investigate nanoscale surface properties. Nevertheless, there is still a lack of literature proposing a complete systematic and rigorous experimental procedure that enables one to obtain reproducible and significant quantitative data. This article focuses on the fundamental experimental difficulties arising when making force curve measurements with the AFM in air. On the basis of this AFM calibration procedure, quantitative assessment values were used to determine, in situ, SAM (or Self Assembled Monolayer)-tip thermodynamic work of adhesion at a local scale, which have been found to be in good agreement with quoted values. Finally, determination of surface energies of functionalised silicon wafers (as received, CH3, OH functionalised silicon wafers) with the AFM (at a local scale) is also proposed and compared with the values obtained by wettability (at a macroscopic scale). In particular, the effect of the capillary forces is discussed. 相似文献