A phantom study for the comparison of different brands of computed tomography scanners and software packages for endovascular aneurysm repair sizing and planning

Objectives: Correct sizing of endoprostheses used for the treatment of abdominal aortic aneurysms is important to prevent endoleaks and migration. Sizing requires several steps and each step introduces a possible sizing error. The goal of this study was to investigate the magnitude of these errors compared to the golden standard: a vessel phantom. This study focuses on the errors in sizing with three different brands of computed tomography angiography scanners in combination with three reconstruction software packages. Methods: Three phantoms with a different diameter, altitude and azimuth were scanned with three computed tomography scanners: Toshiba Aquilion 64-slice, Philips Brilliance iCT 256-slice and Siemens Somatom Sensation 64-slice. The phantom diameters were determined in the stretched view after central lumen line reconstruction by three observers using Simbionix PROcedure Rehearsal Studio, 3mensio and TeraRecon planning software. The observers, all novices in sizing endoprostheses using planning software, measured 108 slices each. Two senior vascular surgeons set the tolerated error margin of sizing on ±1.0?mm. Results: In total, 11.3% of the measurements (73/648) were outside the set margins of ±1.0 mm from the phantom diameter, with significant differences between the scanner types (14.8%, 12.1%, 6.9% for the Siemens scanner, Philips scanner and Toshiba scanner, respectively, p-value?=?0.032), but not between the software packages (8.3%, 11.1%, 14.4%, p-value?=?0.141) or the observers (10.6%, 9.7%, 13.4%, p-value?=?0.448). Conclusions: It can be concluded that the errors in sizing were independent of the used software packages, but the phantoms scanned with Siemens scanner were significantly more measured incorrectly than the phantoms scanned with the Toshiba scanner. Consequently, awareness on the type of computed tomography scanner and computed tomography scanner setting is necessary, especially in complex abdominal aortic aneurysms sizing for fenestrated or branched endovascular aneurysm repair if appropriate the sizing is of upmost importance

A comparative case study of programming language expansion ratios : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Computing Technology at Massey University

An effective size estimation tool must allow an estimate to be obtained early enough to be useful. Some difficulties have been observed in using the traditional lines of code (LOC) measure in software sizing, much of which is due to the need for more detailed design information to be available before an accurate estimate can be achieved. This does not allow the result to be obtained early in the software development process. Moreover, the inherent language-dependency of LOC tends to restrict its use. An alternative measure using Function Point Analysis, developed by Albrecht, has been found to be an effective tool for sizing purposes and allows early sizing. However, the function point measure does not have a sufficient historical base of information for it to be used successfully in all cases with existing models of the software development process. Because lines of code already have a sense of "universality" as the de facto basic measure of software size, it can serve as a useful extension to function points. Language Expansion Ratios are seen as the key in providing such an extension by bridging the gap between function point and lines of code. Several sizing models have made use of expansion ratios in an effort to provide an equivalent size in lines of code in anticipation of its use in productivity studies and related cost models. However, its use has been associated with ranges of variability. The purpose of this thesis is to study Language Expansion Ratios, and the factors affecting them, for several languages based on a standard case study. This thesis surveys the prevailing issues of software size measurement and describes the role and importance of language expansion ratios. It presents the standard case study used and the methodology for the empirical study. The experimental results of measurements of the actual system are analysed and these form the basis for appropriate conclusions on the validity and applicability of the expansion ratios studied. This research shows that the use of Language Expansion Ratios is valid but it is considered inadequate when applied in its present form. This was found to be due to the weighting factors associated with the appropriate function value obtained for the different functional categories of the system

Control theory for principled heap sizing

We propose a new, principled approach to adaptive heap sizing based on control theory. We review current state-of-the-art heap sizing mechanisms, as deployed in Jikes RVM and HotSpot. We then formulate heap sizing as a control problem, apply and tune a standard controller algorithm, and evaluate its performance on a set of well-known benchmarks. We find our controller adapts the heap size more responsively than existing mechanisms. This responsiveness allows tighter virtual machine memory footprints while preserving target application throughput, which is ideal for both embedded and utility computing domains. In short, we argue that formal, systematic approaches to memory management should be replacing ad-hoc heuristics as the discipline matures. Control-theoretic heap sizing is one such systematic approach

Intelligent energy buildings based on RES and Nanotechnology

The paper presents the design features, the energy modelling and optical performance details of two pilot Intelligent Energy Buildings, (IEB). Both are evolution of the Zero Energy Building (ZEB) concept. RES innovations backed up by signal processing, simulation models and ICT tools were embedded into the building structures in order to implement a new predictive energy management concept. In addition, nano-coatings, produced by TiO2 and ITO nano-particles, were deposited on the IEB structural elements and especially on the window panes and the PV glass covers. They exhibited promising SSP values which lowered the cooling loads and increased the PV modules yield. Both pilot IEB units were equipped with an on-line dynamic hourly solar radiation prediction model, implemented by sensors and the related software to manage effectively the energy source, the loads and the storage or the backup system. The IEB energy sources covered the thermal loads via a south façade embedded in the wall and a solar roof which consists of a specially designed solar collector type, while a PV generator is part of the solar roof, like a compact BIPV in hybrid configuration to a small wind turbine

Software cost estimation

The paper gives an overview of the state of the art of software cost estimation (SCE). The main questions to be answered in the paper are: (1) What are the reasons for overruns of budgets and planned durations? (2) What are the prerequisites for estimating? (3) How can software development effort be estimated? (4) What can software project management expect from SCE models, how accurate are estimations which are made using these kind of models, and what are the pros and cons of cost estimation models