Application of fuzzy numerical techniques for product performance analysis in the conceptual and preliminary design stage

Uncertainty and variability modelling tools greatly enhance the value of virtual prototypes at the different design stages of a CAE process. The fuzzy analysis technique is suited to deal with models containing subjective non-deterministic parameters. This technique is finding its way to different disciplines of mechanical engineering. The objective of this paper is to increase the value of this technique in early stages of mechanical design procedures. For this purpose, new numerical procedures are proposed. First, the degree of influence is introduced. This new concept measures the relative effect of highly uncertain design properties on the performance of a design. Next, this paper proposes a new reduced optimisation scheme in order to improve the computational efficiency of the interval analysis, which is at the core of the implementation of the fuzzy technique. The practical applicability of the newly developed procedures is demonstrated on two numerical applications from the automotive industry. The analysed models represent the design at the conceptual stage, and contain parameters with a high and subjective level of uncertainty. The parametrised models are used to demonstrate the value and efficiency of the developed numerical procedures: significant parameters are identified using the degree of influence analysis, the optimal configuration is identified through an interval analysis based on the reduced optimisation scheme, and finally the fuzzy technique is applied as design space exploration tool.     

Thermal resistance assessment in multi-trenched power devices

For the first time the thermal resistance (R_th) of Multi-Trenched (MT) power devices is evaluated and compared with their Deep Trench Isolation flanked (DTI-flanked) and bulk counterparts. The R_th extraction is carried out by adapted test structures based on the four-point heater/sensor method. Additional TCAD simulation supports the experimental stationary values and proves that dynamic heating can limit the MT power devices energy capability.     

Comparative Molecular Dynamics Simulations of Mitogen-Activated Protein Kinase-Activated Protein Kinase 5

The mitogen-activated protein kinase-activated protein kinase MK5 is a substrate of the mitogen-activated protein kinases p38, ERK3 and ERK4. Cell culture and animal studies have demonstrated that MK5 is involved in tumour suppression and promotion, embryogenesis, anxiety, cell motility and cell cycle regulation. In the present study, homology models of MK5 were used for molecular dynamics (MD) simulations of: (1) MK5 alone; (2) MK5 in complex with an inhibitor; and (3) MK5 in complex with the interaction partner p38α. The calculations showed that the inhibitor occupied the active site and disrupted the intramolecular network of amino acids. However, intramolecular interactions consistent with an inactive protein kinase fold were not formed. MD with p38α showed that not only the p38 docking region, but also amino acids in the activation segment, αH helix, P-loop, regulatory phosphorylation region and the C-terminal of MK5 may be involved in forming a very stable MK5-p38α complex, and that p38α binding decreases the residual fluctuation of the MK5 model. Electrostatic Potential Surface (EPS) calculations of MK5 and p38α showed that electrostatic interactions are important for recognition and binding.     

Salomon: Automatic Abstracting of Legal Cases for Effective Access to Court Decisions

The SALOMON project is a contribution to the automatic processing of legal texts. Its aim is to automatically summarise Belgian criminal cases in order to improve access to the large number of existing and future cases. Therefore, techniques are developed for identifying and extracting relevant information from the cases. A broader application of these techniques could considerably simplify the work of the legal profession.A double methodology was used when developing SALOMON: the cases are processed by employing additional knowledge to interpret structural patterns and features on the one hand and by way of occurrence statistics of index terms on the other. As a result, SALOMON performs an initial categorisation and structuring of the cases and subsequently extracts the most relevant text units of the alleged offences and of the opinion of the court. The SALOMON techniques do not themselves solve any legal questions, but they do guide the user effectively towards relevant texts.     

Intelligent Information Extraction from Legal Texts

Presently, we are confronted with an enormous amount of legal documents, which are increasingly recorded in electronic format. There is a need to make the information in legal texts easily and automatically accessible. In this paper we argue that in the legal field, where we are confronted with specific text types, knowledge about discourse structures and the linguistic cues that signal them is very valuable to incorporate in information extraction systems and in text processing systems in general. We also demonstrate the need for adequate formalisms for representing discourse patterns. However, intertextual analysis of texts that describes and explains the properties of text types and genres is underdeveloped in the legal field.     

Recent advances in non-probabilistic approaches for non-deterministic dynamic finite element analysis

Summary There is a growing awareness of the impact of non-deterministic model properties on the numerical simulation of physical phenomena. These non-deterministic aspects are of great importance when there is a large amount of information to be retrieved from the numerical analysis, as for instance in a numerical reliability study or reliability based optimisation during a design process. Therefore, the non-deterministic properties form a primordial part of a trustworthy virtual prototyping environment. The implementation of such a virtual prototyping environment requires the inclusion of non-deterministic properties in the numerical finite element framework. This articel gives an overview of the emerging non-probabilistic approaches for non-deterministic numerical analysis, and compares them to the classical probabilistic methodology. Their applicability in the context in engineering design is discussed. The typical implementation strategies applied in literature are reviewed. A new concept is introduced for the calculation of envelope frequency response functions. This method is explained in detail and illustrated on a numerical example.     

The thickness profile of ultra‐high molecular weight polyethylene films during sequential biaxial drawing

In this study, the evolution of the thickness profile of UHMW‐polyethylene films during sequential biaxial drawing is studied. The basic assumption is that a nonuniform thickness distribution of the drawn film is the result of the amplification of initial imperfections. Finite element simulations of the drawing process have been performed in which the drawing of a piece of film with a geometric imperfection is considered. For these numerical simulations, a viscoelastic model is adopted. Although the model does not describe the behavior of UHMW‐PE films in full detail, it is able to capture typical features of inhomogeneous deformation. The most striking observation is that severe localization occurs at the beginning of the second drawing step (i.e. in the direction transverse to the first step). In this stage of the drawing process, a localization band develops. These phenomena are also observed in validation experiments. A discrepancy between the simulations and the validation experiments is observed at the end of the drawing process. In the simulations, the deformation is stabilized again, and the resulting thickness profile is practically uniform. In the experiments however, the bad thickness profile at the beginning of the second drawing step is conserved up to the end of the drawing process. The simulations have been performed for different process parameters. Hence, it is possible to access the influence of these parameters on the evolution of the thickness profile. Furthermore, a suggestion is done to explain the deformation phenomena. The stability of the deformation can be determined from stress‐strain curves during the biaxial drawing process. It is concluded that, although no absolute values are acquired, trends are predicted correctly and they can serve as quidelines for process control.     

Back pain and its correlates among workers in family care

This study is based on the empirical fact that among nurses large variations occur not only in clinical competency but also in individual productivity. The article proposes that competency-based targeted staff development programs can improve productivity as well as nursing performance. Research presented here shows that the nurses on units using targeted staff development increased the time spent on professional and direct care and reduced nonprofessional and indirect care tasks in comparison to nurses on the control nursing unit.     

Validated measurements of the uranium isotopic signature in human urine samples using magnetic sector-field inductively coupled plasma mass spectrometry

Increased interest in measuring uranium isotope ratios in environmental samples (biological materials, soils, dust particles, water) has come from the necessity to assess the health impact of the use of depleted uranium (DU) based ammunitions during recent military conflicts (e.g., Gulf war, Kosovo) and from the need to identify nondeclared nuclear activities (nuclear safeguards). In this context, very important decisions can arise which have to be based on measurement data of nondisputable uncertainty. The present study describes the certification to 2.5% (k = 2) relative combined uncertainty of n(235U)/n(238U) at ultralow uranium levels (approximately 5-20 pg g(-1)) in human urine samples. After sample decomposition and matrix separation, the isotope ratios were measured by means of a single-detector magnetic sector-field inductively coupled plasma mass spectrometry instrument fitted with an ultrasonic nebulizer. Correction for mass discrimination effects was obtained by means of the certified isotopic reference material IRMM-184. The analytical procedure developed was validated in three complementary ways. First, all major sources of uncertainty were identified and propagated together following the ISO/GUM guidelines. Second, this quality was controlled with a matrix matching NUSIMEP-3 sample (approximately 0.06-0.7% difference from certified). Third, the instrumental part of the procedure was proven to be reproducible from the confirmation of the results obtained for three samples remeasured 7 months later (approximately 1.5% difference). The results obtained for 33 individuals indicated that none seemed to have been exposed to contamination by DU.