Performance of stochastic and deterministic dithered quantizers

In this paper, the authors discuss the use of deterministic and stochastic dither sequences in analog-to-digital conversion including data postprocessing. Properties of both types of dither signals are highlighted, and a performance comparison is carried out by considering residual bias and mean square error. It is concluded that superior performance can be attained by deterministic dither in terms of system resolution and accuracy, at the expense of worse spectral characteristics. Experimental results are provided to support simulations and theoretical analysis     

Effective ADC linearity testing using sinewaves

This paper deals with the effectiveness of the sinewave histogram test (SHT) for testing analog-to-digital converters. The implementation is discussed, with respect to the adopted procedures and to the choice of relevant parameters. Some of the published approximations currently limiting the characterization of the test performance are removed. The statistical efficiency of the SHT is evaluated by comparing the associated estimator variance with the corresponding Crame/spl acute/r-Rao lower bound, theoretically derived assuming sinewaves corrupted by Gaussian noise. Finally, both simulation and experimental results are presented to validate the proposed approach.     

Digital Curve Length Calculation by Using B-spline

A new method for digital curve length calculation based on the approximation with a B-spline has been introduced where the control points of a B-spline curve are the pixel center points. An approximate length of the digital curve is determined by calculating the length of the continuous B-spline curve. In the paper several examples are presented and the calculated lengths are compared to other methods found in the literature. The advantage of the proposed method is in the approximation of the digital curve with the continuous curve rather than with piecewise linear sections used by most other methods.     

Uerpmann-Wittzack,Robert (Hrsg.): Das neue Computergrundrecht,LIT Verlag Dr. W. Hopf,Berlin 2009, ISBN 978-3-643-10155-6

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Methods for quantitative usability requirements: a case study on the development of the user interface of a mobile phone

Quantitative usability requirements are a critical but challenging, and hence an often neglected aspect of a usability engineering process. A case study is described where quantitative usability requirements played a key role in the development of a new user interface of a mobile phone. Within the practical constraints of the project, existing methods for determining usability requirements and evaluating the extent to which these are met, could not be applied as such, therefore tailored methods had to be developed. These methods and their applications are discussed.

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Simple active method for reducing magnetic interference in a thermoelectrically cooled photomultiplier tube

We present a simple modification for thermoelectrically cooled photomultiplier tube (PMT) assemblies that eliminates the magnetic interference between the peltier element and the PMT. An active compensation is accomplished by forming current loops of the wires of the peltier element and placing them in such a way that they eliminate the interfering magnetic field. It is demonstrated that the improved system reduces measurement errors of the order of 1% to statistical noise at the level of 0.07%.     

Comparison of proteomic biomarker panels in urine and serum for ovarian cancer diagnosis

Purpose : The purposes of this study were to confirm previously found candidate epithelial ovarian cancer biomarkers in urine and to compare a paired serum biomarker panel and a urine biomarker panel from the same study cohort with regard to the receiver operating characteristic curve (ROC) area under the ROC curve (AUC) values. Experimental design : Four significant urine biomarkers were confirmed among 130 pelvic mass patients in the present study. The four biomarkers form a potential urine biomarker panel. From the same study cohort, the potential urine biomarker panel was compared to a serum biomarker panel, consisting of seven proteins/peptides, OvaRI. Results : Multivariate analysis of the urine panel demonstrated a significant differentiation (p<0.0001) between epithelial ovarian cancer patients and patients with benign ovarian pelvic masses. The ROC AUC of the urine panel was 0.84 and the ROC AUC of OvaRI was 0.83. Combining the urine panel with OvaRI demonstrated a significant contribution from both, for urine peaks, OR=2.12 and for OvaRI, OR=1.39; the ROC AUC of this model was 0.88. Conclusions and clinical relevance : We demonstrated that both urine and serum can be used individually or in combination to potentially aid in ovarian cancer diagnostics. Urine proteomic profiling could provide biomarkers for the non‐invasive test required in clinical practice.     

Validation of multiparametric MRI by histopathology after nephrectomy: a case study

Magnetic Resonance Materials in Physics, Biology and Medicine - Renal multiparametric MRI (mpMRI) is a promising tool to monitor renal allograft health to enable timely treatment of chronic...