Yield fluctuations and defect models

This paper establishes a general statistical framework for analyzing wafer fallout data in order to obtain information about process induced defects. The statistical behavior of fallout during testing is characterized. A general model is presented that relates the yield to the test coverage and the defect distribution. This model incorporates arbitrary variations in the occurrence probabilities of different defects and arbitrary dependencies between the defects, although it still ignores correlations between the occurrence probability of a defect and whether or not this defect is detected. A statistical acceptance criterion for this model is proposed, based on a convexity property of the model. It is applied to a published set of yield data and shows that some striking features in these data cannot be due to mere statistical fluctuations. Some explanations of these features will be discussed.     

An experimental network-mediated study support system

Abstract  The route towards a functional design and its principle components are described for a network communication system that connects students and tutors in a distance course. The system is designed mainly to mediate the study support provided by the tutor to individual students. The key concept is the 'study environment' rather than computer-mediated communication. The study environment consists of the student's computer, the network, the telephone, the tutor, the fellow students and the printed materials. A special program integrates all support tasks, ranging from mapping the student's progress to the automatic exchange of the outcomes and corrections of assignments.     

A novel point mutation in the translation initiation codon of the pre-pro-vasopressin-neurophysin II gene: cosegregation with morphological abnormalities and clinical symptoms in autosomal dominant neurohypophyseal diabetes insipidus

Autosomal dominant neurohypophyseal diabetes insipidus (ADNDI) is a rare variant of idiopathic central diabetes insipidus. Several different mutations in the human vasopressin-neurophysin II (AVP-NP II) gene have been described. We studied nine family members from three generations of an ADNDI pedigree at the clinical, morphological, and molecular levels. AVP concentrations were measured during diagnostic fluid restriction tests. Coronal and sagittal high resolution T1-weighted images of the pituitary were obtained from affected and healthy family members. PCR was used to amplify the AVP-NP II precursor gene, and PCR products were directly sequenced. Under maximal osmotic stimulation, AVP serum levels were close to or below the detection limit in affected individuals. Magnetic resonance imaging studies revealed the characteristic hyperintense ("bright spot") appearance of the posterior pituitary in two healthy family members. This signal was absent in all four ADNDI patients examined. The coding sequences of AVP and its carrier protein, neurophysin II, were normal in all family members examined. Affected individuals showed a novel single base deletion (G 227) in the translation initiation codon of the AVP-NP II signal peptide on one allele. The mutation in the AVP-NP II leader sequence appears to be responsible for the disease in this kindred, possibly by interfering with protein translocation. The absence of the hyperintense posterior pituitary signal in affected individuals could reflect deficient posterior pituitary function.     

Automated serum peptide profiling using novel magnetic C18 beads off-line coupled to MALDI-TOF-MS

Serum peptide profiling by MS is an emerging approach for disease diagnosis and biomarker discovery. A magnetic bead‐based method for off‐line serum peptide capture coupled to MALDI‐TOF‐MS has been recently introduced. However, the reagents are not available to the general scientific community. Here, we developed a protocol for serum peptide capture using novel magnetic C18 beads, and automated the procedure on a high‐throughput magnetic particle processor. We investigated bead equilibration, peptide binding and peptide elution conditions. The method is evaluated in terms of peaks counts and reproducibility of ion intensities in control serum. Overall, the DynaBead‐RPC18‐based serum sample processing protocol reported here is reproducible, robust and allows for the detection of ?200 peptides at m/z 800–4000 of serum that was allowed to clot for 1 h. The average intra‐experiment %CV of normalized ion intensities for crude serum and 0.5% TFA/0.15% n‐octyl glucoside‐treated serum, respectively, were 12% (range 2–38%) and 10% (3–21%) and the inter‐experiment %CVs were 24% (10–53%) and 31% (10–59%). Importantly, this method can be used for serum peptide profiling by anyone in possession of a MALDI‐TOF instrument. In conjunction with the KingFisher® 96, the whole serum peptide capture procedure is high‐throughput (?20 min per isolation of 96 samples in parallel), thereby facilitating large‐scale disease profiling studies.     

Verification and synthesis of co-simulation algorithms subject to algebraic loops and adaptive steps

International Journal on Software Tools for Technology Transfer - Simulation-based analyses are becoming increasingly vital for the development of cyber-physical systems. Co-simulation is one such...     

Harmony filter: A robust visual tracking system using the improved harmony search algorithm

In this article a novel approach to visual tracking called the harmony filter is presented. It is based on the Harmony Search algorithm, a derivative free meta-heuristic optimisation algorithm inspired by the way musicians improvise new harmonies. The harmony filter models the target as a colour histogram and searches for the best estimated target location using the Bhattacharyya coefficient as a fitness metric. Experimental results show that the harmony filter can robustly track an arbitrary target in challenging conditions. We compare the speed and accuracy of the harmony filter with other popular tracking algorithms including the particle filter and the unscented Kalman filter. Experimental results show the harmony filter to be faster and more accurate than both the particle filter and the unscented Kalman filter.     

Multi-core symbolic bisimulation minimisation

We introduce parallel symbolic algorithms for bisimulation minimisation, to combat the combinatorial state space explosion along three different paths. Bisimulation minimisation reduces a transition system to the smallest system with equivalent behaviour. We consider strong and branching bisimilarity for interactive Markov chains, which combine labelled transition systems and continuous-time Markov chains. Large state spaces can be represented concisely by symbolic techniques, based on binary decision diagrams. We present specialised BDD operations to compute the maximal bisimulation using signature-based partition refinement. We also study the symbolic representation of the quotient system and suggest an encoding based on representative states, rather than block numbers. Our implementation extends the parallel, shared memory, BDD library Sylvan, to obtain a significant speedup on multi-core machines. We propose the usage of partial signatures and of disjunctively partitioned transition relations, to increase the parallelisation opportunities. Also our new parallel data structure for block assignments increases scalability. We provide SigrefMC, a versatile tool that can be customised for bisimulation minimisation in various contexts. In particular, it supports models generated by the high-performance model checker LTSmin, providing access to specifications in multiple formalisms, including process algebra. The extensive experimental evaluation is based on various benchmarks from the literature. We demonstrate a speedup up to 95\(\times \) for computing the maximal bisimulation on one processor. In addition, we find parallel speedups on a 48-core machine of another 17\(\times \) for partition refinement and 24\(\times \) for quotient computation. Our new encoding of the reduced state space leads to smaller BDD representations, with up to a 5162-fold reduction.

     

Tools for the construction and analysis of systems

In order to develop reliable software and systems, we depend on practical techniques for the construction and analysis of such software and systems. This special issue of Software Tools for Technology Transfer presents various tool-supported techniques that can help with the construction and analysis of such reliable software and systems. The papers in this special issue are extended versions of selected conference papers from the proceedings of the 24th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS 2018).

     

Automatic feedback control of relative blood volume changes during hemodialysis improves blood pressure stability during and after dialysis

Automatic feedback systems have been designed to control relative blood volume changes during hemodialysis (HD) as hypovolemia plays a major role in the development of dialysis hypotension. Of these systems, one is based on the concept of blood volume tracking (BVT). BVT has been shown to improve intra-HD hemodynamic stability. We first questioned whether BVT also improves post-HD blood pressure stability in hypotension-prone patients and second, whether BVT is effective in reducing the post-HD weight as many hypotension-prone patients are overhydrated because of an inability to reach dry weight. After a 3-week period on standard HD, 12 hypotension-prone patients were treated with two consecutive BVT treatment protocols. During the first BVT period of 3 weeks, the post-HD target weight was kept identical compared with the standard HD period (BVT-constant weight; BVT-cw). During the second BVT period of 6 weeks, we gradually tried to lower the post-HD target weight (BVT-reduced weight; BVT-rw). In the last week of each period, we studied intra-HD and 24 hr post-HD blood pressure behavior by ambulatory blood pressure measurement (ABPM). Pre- and post-HD weight did not differ between standard HD and either BVT-cw or BVT-rw. Heart size on a standing pre-dialysis chest X-ray did not change significantly throughout the study. There were less episodes of dialysis hypotension during BVT compared with standard HD (both BVT periods: p<0.01). ABPM data were complete in 10 patients. During the first 16 hr post-HD, systolic blood pressure was significantly higher with BVT in comparison with standard HD (both BVT periods: p<0.05). The use of BVT in hypotension-prone patients is associated with higher systolic blood pressures for as long as 16 hr post-HD. BVT was not effective in reducing the post-HD target weight in this patient group.