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Identifiability conditions for linear systems operating in closed loop

The problem of identifiability of processes using measurements obtained under closed loop operation is treated. Single input-single output systems are considered. It is assumed that the feedback is time invariant, linear and noise free. It is also assumed that no external input signal is injected. Conditions, which are simultaneously necessary and sufficient for identifiability are derived. The re

Tin whiskers: experiments and modelling

Tin whiskers are hair-like single crystals that spontaneously grow from tin-coated surfaces. Whiskers are commonly found in electronic components, where tin coatings are used in, e.g., soldering applications, and to protect components from corrosion. Whiskers are known to cause short-circuits leading to failure of electronic components. The exact mechanisms responsible for whisker formation and gr

A theoretical analysis of recursive identification methods

In this paper five different recursive identification methods will be analyzed and compared, namely recursive versions of the least squares method, the instrumental variable method, the generalized least squares method, the extended least squares method and the maximum likelihood method. They are shown to be similar in structure and need of computer storage and time. Making use of recently develop

Convergence of identification methods based on the instrumental variable approach

A class of identification methods, proposed in [3], are based on the instrumental variable principle. This correspondence contains a continued analysis of convergence of the parameter estimates of these methods. Alternative, sufficient conditions for convergence to correct values are given. It is also shown by construction of counter-examples that the methods do not converge under general conditio

Open source ERP business model framework

ERP systems became popular with large organizations in the 1990s. In the 21st Century, these products were expanded by addition of supply chain management (SCM) and customer relationship management (CRM), as well as access through the Web, creating the ERP II concept. Efforts to increase the market led vendors to serve not only large organizations, but also focus more on small-to-medium sized ente

Convergence properties of the generalised least squares identitication method

Convergence properties of the generalized least squares method are analyzed. The method can be interpreted as optimization of a likelihood function. The number of local maximum points of the likelihood function is examined. It is shown that this number is influenced by the signal to noise ratio. This theoretical result is illustrated by numerical examples using plant measurements. It is also prove

Influence of graphite nanoadditives to vegetable-based oil on machining performance when MQCL assisted hard turning

The current study demonstrates through experiment, the effect of solid lubricant assisted minimum quantity cooling lubrication (MQCL) when turning tempered (~60 HRC) alloyed steel Uddeholm Caldie with cemented carbide tools on the process performance. In MQCL application, nanosized graphite nanoplatelets (GnP) solid lubricant powder was dispersed (0.2% vol.) in rapeseed oil based lubricant “ECOLUB

On the uniqueness of maximum likelihood identification

The maximum likelihood method of identification is a powerful tool for obtaining mathematical models of dynamic processes. To apply this method a loss function has to be minimized. The aim of the paper is an investigation of the local minimum points of this loss function for a common structure of a general form. If the loss function has more than one local minimum point, numerical problems can occ

Tool Wear Mechanisms of pcBN tooling during High-Speed Machining of Gray Cast Iron

The presence of graphite particles in gray cast iron commonly implies a good machinability, especially if compared to common steels. However, increasing industrial demands have resulted in a new interest for high-speed machining of these materials with higher performing tool materials than the traditionally used. Thus, the research presented in this paper focuses on evaluating the active tool wearThe presence of graphite particles in gray cast iron commonly implies a good machinability, especially if compared to common steels. However, increasing industrial demands have resulted in a new interest for high-speed machining of these materials with higher performing tool materials than the traditionally used. Thus, the research presented in this paper focuses on evaluating the active tool wear

Wound Dehiscence after Posterior Sagittal Anorectoplasty in Children with Anorectal Malformations

Aim of the Study. To assess the frequency of and identify contributing factors to wound dehiscence after posterior sagittal anorectoplasty (PSARP) in children born with anorectal malformations (ARM). Methods. Ethical approval was obtained (DNR 2017/191). Charts of all children with anorectal malformations (ARM) reconstructed with PSARP, limited PSARP, or PSARVUP at a tertiary centre of paediatric

Comparison of patients with and without pre-existing lymphoma at diagnosis of primary Sjögren’s syndrome

Objective: In the 2016 American College of Rheumatology/European League Against Rheumatism classification criteria for primary Sjögren’s syndrome (pSS), pre-existing lymphoma is not an exclusion criterion for pSS diagnosis, as in earlier criteria. We aimed to explore whether there are differences between pSS patients with and without pre-existing lymphoma at pSS diagnosis. Method: Patients with IC

Att söka kungligt tillstånd för giftermål : äktenskapsansökningar från besläktade personer under svenskt 1700-tal

To Ask for the King’s Permission to Marriage: Applications for Marriage between Relatives in Eighteenth Century Sweden. In early modern Western society regulations against incestuous relationships were primarily justified by religion, and kinship by blood and kinship by marriage were treated equally. In the seventeenth and eighteenth centuries Swedish law was among the strictest in these matters,

Iterative High Resolution Tomography from Combined High-Low Resolution Sinogram Pairs

In some cases of tomography we can only gain high resolution projections of the object with only partial coverage, whereas only a small part of the object – a given Region of Interest (ROI) – is fully covered by high resolution projections. In such cases the structures outside the region of interest cause artefacts to appear in the reconstructed image and degrade the image quality of the tomogram.

Förbjuden kärlek

Känslor och känsloyttringar kan förefalla vara allmänmänskliga företeelser, men forskning visar att den generella inställningen till känslor har skiftat mellan olika kulturer såväl som inom en och samma kultur över olika tidsperioder. Under medeltiden värderades exempelvis kontroll och förnuft högre än känslosamhet i det västerländska samhället, men från och med sent 1700-tal kom känslor och kärleResearch has shown that the general attitudes towards emotions have shifted between different cultures as well as within one culture over different periods. During the Middle Ages, for example, control and reason were considered more desirable human qualities than emotions in Western societies. However, from the late 1700s emotions and empathy were described with increasingly positive terms. From

Mapping physical therapy research : The geographical affiliations and methodological quality of 2,959 randomized controlled trials

Evidence suggests that research benefits from diversity, yet science is concentrated to a small group of countries. Diversity in physical therapy research has so far not been studied thoroughly, and this is the first study to map physical therapy research geographically. The objective was to study the frequency and methodological quality of physical therapy-related randomized controlled trials (RC

Output regulation and internal models : A frequency domain approach

The algebraic regulator problem is formulated and solved in a transfer matrix setting. It is shown that, provided the closed loop system disregarding disturbances is stable, a necessary and sufficient condition for output regulation to take place is that the open loop path consisting of the plant and compensator in cascade, contains a suitably defined internal model of the environment. The disturb