An integrated framework for the analysis of dependable interactive systems (IFADIS): Its tool support and evaluation

This paper discusses a method for the analysis of dependable interactive systems using model checking, and its support by a tool designed to make it accessible to a broader community. The method and the tool are designed to be of value to system engineers, usability engineers and software engineers. It has been designed to help usability engineers by making those aspects of the analysis relevant to them explicit while concealing those aspects of modelling and model checking that are not relevant. The paper presents the results of a user evaluation of the effectiveness of aspects of the tool and how it supports the proposed method. The tool was constructed while both authors worked in the Human Computer Interaction Group. Department of Computer Science, University of York, UK.     

Piezoresistive encoders for ratcheting actuation systems

This paper introduces piezoresistive encoders that can provide information on the performance of ratcheting actuation systems, and may be useful in future applications that require position determination. One unique feature of the encoders is that they gain their piezoresistance from the bulk properties of polycrystalline silicon without additional fabrication steps. In this study, two encoders are considered: a parallel-guiding encoder in an on-chip Wheatstone bridge, and a piezoresistive microdisplacement transducer (PMT) encoder in an on-chip Wheatstone bridge. In tests, the encoders each generated measurable signals, with the PMT encoder providing the best sensitivity. The PMT encoder operated at actuation frequencies up to 920 Hz and produced a signal between 2 V and 3.2 V (applied gain of 1000). The PMT encoder produced unique signals corresponding to distinct ideal and non-ideal behaviors of a ratchet wheel actuation system.     

Recovery and recrystallization in Cold-Rolled Al-SiCw composites

Recrystallization behavior has been studied in 50, 70, and 90 pct cold-rolled silicon carbide whisker-reinforced aluminum composites containing fine aluminum-oxide particles. The distribution of aluminum-oxide particles in the composites was not uniform. Macrohardness measurement, transmission electron microscopy (TEM), and light microscopy were used in the investigation. It was found that in regions with low aluminum oxide content, the introduction of SiC whiskers resulted in recovery reactions during and after cold rolling and in an increase in the growth rate of subgrains during annealing. These recovery reactions were enhanced by an increase in the degree of deformation. The number density of nuclei varied between areas with different contents of aluminum-oxide particles. The impingement of nuclei and recovery reactions limited the growth of nuclei, resulting in a process where recrystallization (growth of nuclei by high-angle grain boundary migration) and extended recovery (growth of subgrains) took place simultaneously. The relative amounts of recrystallization and extended recovery that occur simultaneously affect the recrystallization kinetics as well as the grain size distribution and texture after recrystallization.     

Recanalized umbilical vein in portal hypertension

Experience with splenoportography suggests that patency of the umbilical vein occurs in about 9% of the patients with portal hypertension. A widely patent umbilical vein might serve as a decompressive portosystemic shunt. Percutaneous transhepatic portography was performed in 107 patients with cirrhosis of the liver and portal hypertension. A patent umbilical vein was found in 28 patients (26%). This finding significantly paralleled the number and size of other collateral veins, apart from gastroesophageal varices. No significant relation was found between umbilical vein patency and portal pressure, extrahepatic shunting, variceal bleeding, or ascites. It is concluded that a large patent umbilical vein does not effectively relieve portal hypertension, prevent gastroesophageal varices, or protect against variceal bleeding or ascites.     

Microalbuminuria as predictor of atherosclerotic cardiovascular disease in IDDM

The aim of this follow-up study was to assess whether slightly elevated urinary albumin excretion, i.e., microalbuminuria, precedes development of atherosclerotic vascular disease in IDDM. Out of 259 IDDM-patients 30 developed vascular disease during 2,457 person-years. Microalbuminuria was significantly predictive of vascular disease (hazard ratio (95% confidence interval) 1.06 (1.02-1.18) per 5 mg/24 hours increase in urinary albumin excretion; p = 0.002). The predictive effect was independent of age, sex, blood pressure, tobacco smoking, serum concentrations of total-cholesterol, HDL-cholesterol, sialic acid, and von Willebrand factor, and of haemoglobin A1c, insulin dose, diabetes duration, and diabetic nephropathy (hazard ratio (95% confidence interval) 1.04 (1.01-1.08) per 5 mg/24 hours increase in urinary albumin excretion; p = 0.03). It is concluded that slightly elevated urinary albumin excretion is an independent predictor of atherosclerotic vascular disease in insulin-dependent diabetes mellitus.     

An algebraic framework for temporal attribute characteristics

Most real-world database applications manage temporal data, i.e., data with associated time references that capture a temporal aspect of the data, typically either when the data is valid or when the data is known. Such applications abound in, e.g., the financial, medical, and scientific domains. In contrast to this, current database management systems offer preciously little built-in query language support for temporal data management. This situation persists although an active temporal database research community has demonstrated that application development can be simplified substantially by built-in temporal support. This paper's contribution is motivated by the observation that existing temporal data models and query languages generally make the same rigid assumption about the semantics of the association of data and time, namely that if a subset of the time domain is associated with some data then this implies the association of any further subset with the data. This paper offers a comprehensive, general framework where alternative semantics may co-exist. It supports so-called malleable and atomic temporal associations, in addition to the conventional ones mentioned above, which are termed constant. To demonstrate the utility of the framework, the paper defines a characteristics-enabled temporal algebra, termed CETA, which defines the traditional relational operators in the new framework. This contribution demonstrates that it is possible to provide built-in temporal support while making less rigid assumptions about the data and without jeopardizing the degree of the support. This moves temporal support closer to practical applications.     

Review and analysis of solutions of the three point perspective pose estimation problem

In this paper, the major direct solutions to the three point perspective pose estimation problems are reviewed from a unified perspective beginning with the first solution which was published in 1841 by a German mathematician, continuing through the solutions published in the German and then American photogrammetry literature, and most recently in the current computer vision literature. The numerical stability of these three point perspective solutions are also discussed. We show that even in case where the solution is not near the geometric unstable region, considerable care must be exercised in the calculation. Depending on the order of the substitutions utilized, the relative error can change over a thousand to one. This difference is due entirely to the way the calculations are performed and not due to any geometric structural instability of any problem instance. We present an analysis method which produces a numerically stable calculation.