Stochastic finite element analysis of steel structures

The paper describes two well known but adapted methods for calculating the probability of failure of structures. First the First Order Reliability Method (FORM) is described using an adapted response surface. Secondly the Directional Sampling (DS) procedure is described using truncated stochastic distributions. Both methods are implemented in...

Assessment factors for human health risk assessment: A discussion paper

The general goal of this discussion paper is to contribute toward the further harmonization of human health risk assessment. It first discusses the development of a formal, harmonized set of assessment factors. The status quo with regard to assessment factors is reviewed, that is, the type of factors to be identified, the range of values...

Speed-Up of the Monte Carlo Method by Using a Physical Model of the Dempster-Shafer Theory

By using the Monte Carlo method, we can obtain the minimum value of a function V(r) that is generally associated with the potential energy. In this paper we present a method that makes it possible to speed up the classical Monte Carlo method. The new method is based on the observation that the Bolzmann transition probability and the concept of...

Dynamic assessment of the ecological risk of the discharge of produced water from oil and gas producing platforms

Since 1991 the North Sea countries (UK, Netherlands, Norway and Denmark) have put a lot of effort in the development of a decision support system for the legislation of the use and discharge of offshore exploration, drilling and production chemicals. The heart of this so-called 'harmonised mandatory control system' is the 'chemical hazard...

Small Surface Target Detection with EO/IR Sensors

The detection of small surface targets at sea is an increasing requirement for warships. The present sensors on board do not provide the required detection probabilities for these low observable targets like small rubber boats, floating mines, periscopes, people etc. The reason for the low probability of detection is not only the low contrast...

Probability of flooding: An uncertainty analysis

In the Netherlands a new safety approach concerning the flood defences will probably be implemented in the near future. Therefore, an uncertainty analysis is currently being carried out to determine the uncertainty in the probability of flooding . The uncertainty of the probability of flooding could indicate whether we are ready for the change...

The JCSS probabilistic model code

The JCSS is developing a model code for full probabilistic design. This note gives an overview of the set up and contents of this code. © 1997 Elsevier Science Ltd.

The effect of a priori probability and complexity on decision making in a supervisory control task

In the present study we investigated how monitoring and fault management in a ship control task are affected by complexity and a priori probability of disturbances. Partici-pants were required to supervise four independent shipping subsystems and to adjust the subsystems whenever deviations occurred. However, in order to apply the correct action...

Optimum condition-based maintenance policies for deteriorating systems with partial information

Systems are considered which deteriorate as time goes on and whose conditions can be observed. The optimum maintenance policy with respect to cost is determined, based on a continuous deterioration process, by formulating the decision process as a discrete Markov decision problem. Examples from the field of civil engineering are given. The...

Evaluation of infrared signature suppression of ships

Reduction of the infrared signature of warships helps to increase their survivability. Two methods to reduce the infrared signature are discussed: the cooling of exhaust gases and the application of low emissivity paint. The infrared signature of a generic frigate has been calculated with and without signature reduction. The signature values are...

Numerical modeling of turbulent jet diffusion flames in the atmospheric surface layer

The evolution of turbulent jet diffusion flames of natural gas in air is predicted using a finite-volume procedure for solving the flow equations. The model is three dimensional, elliptic and based on the conserved-scalar approach and the laminar flamelet concept. A laminar flamelet prescription for temperature, which is in agreement with...

Multiple hypothesis clustering in radar plot extraction

False plots and plots with inaccurate range and Doppler estimates may severely degrade the performance of tracking algorithms in radar systems. This paper describes how a multiple hypothesis clustering technique can be applied to mitigate the problems involved in plot extraction. The measures of confidence for each hypothesis are based on fuzzy...

Polyethylene terephthalate bottles (PRBs): A health and safety assessment

As part of a multi-client project, the potential public health risks of the reuse of polyethylene terephthalate (PET) refillable bottles (PRBs) following possible misuse has been investigated. Participants in the project provided data and information from previous studies conducted independently at contract laboratories. These studies were...

Gust modelling for wind loading

In this paper the TNO gust analysis method and the resulting TNO gust model are described. The method has been applied to a set of 700 hours of stationary wind speed time series measured at the meteorological mast at Cabauw, The Netherlands. The results are discussed in this paper. The TNO gust model has been developed for the calculation of...

Hernieuwde schatting van het aantal HIV-seropositieven in Nederland [Re-estimation of the number of HIV-seropositives in the Netherlands]

Eind 1990 verschenen in dit tijdschrift twee artikelen over het aantal met HIV geïnfecteerden in Nederland. Hieruit bleek dat het aantal HIV-seropositieven lager lag dan eerder werd aangenomen, maar dat desondanks een stijgend aantal AIDS-patiënten verwacht mocht worden. In uitkomsten liepen de twee onderzoeken niet ver uiteen. Jager et al....

Delaying childbearing: Effect of age on fecundity and outcome of pregnancy

Objectives - To study the age of the start of the fall (critical age) in fecundity; the probability of a pregnancy leading to a healthy baby taking into account the age of the woman; and, combining these results, to determine the age dependent probability of getting a healthy baby. Design - Cohort study of all women who had entered a donor...