Requirements Abstraction Model

Software requirements arrive in different shapes and forms to development organizations. This is particularly the case in market-driven requirements engineering, where the requirements are on products rather than directed towards projects. This results in challenges related to making different requirements comparable. In particular, this situation was identified in a collaborative effort between academia and industry. A model, with four abstraction levels, was developed as a response to the industrial need. The model allows for placement of requirements on different levels and supports abstraction or break down of requirements to make them comparable to each other. The model was successfully validated in several steps at a company. The results from the industrial validation point to the usefulness of the model. The model will allow companies to ensure comparability between requirements, and hence it generates important input to activities such as prioritization and packaging of requirements before launching a development project.

Local histograms for design of transfer functions in direct volume rendering

Direct volume rendering (DVR) is of increasing diagnostic value in the analysis of data sets captured using the latest medical imaging modalities. The deployment of DVR in everyday clinical work, however, has so far been limited. One contributing factor is that current transfer function (TF) models can encode only a small fraction of the user's domain knowledge. In this paper, we use histograms of local neighborhoods to capture tissue characteristics. This allows domain knowledge on spatial relations in the data set to be integrated into the TF. As a first example, we introduce partial range histograms in an automatic tissue detection scheme and present its effectiveness in a clinical evaluation. We then use local histogram analysis to perform a classification where the tissue-type certainty is treated as a second TF dimension. The result is an enhanced rendering where tissues with overlapping intensity ranges can be discerned without requiring the user to explicitly define a complex, multidimensional TF     

Multi-touch table system for medical visualization: application to orthopedic surgery planning

Medical imaging plays a central role in a vast range of healthcare practices. The usefulness of 3D visualizations has been demonstrated for many types of treatment planning. Nevertheless, full access to 3D renderings outside of the radiology department is still scarce even for many image-centric specialties. Our work stems from the hypothesis that this under-utilization is partly due to existing visualization systems not taking the prerequisites of this application domain fully into account. We have developed a medical visualization table intended to better fit the clinical reality. The overall design goals were two-fold: similarity to a real physical situation and a very low learning threshold. This paper describes the development of the visualization table with focus on key design decisions. The developed features include two novel interaction components for touch tables. A user study including five orthopedic surgeons demonstrates that the system is appropriate and useful for this application domain.     

Microchip immobilized enzyme reactors for hydrolysis of methyl cellulose

Microchip immobilized enzyme reactors (microIMERs) with immobilized endoglucanases were applied for the hydrolysis of methyl cellulose (MC). MCs of various molecular weights were hydrolyzed using two microIMERs containing immobilized celloendoglucanase Cel 5A from Bacillus agaradhaerens (BaCel 5A) connected in series. Hydrolysis by the microIMER could be confirmed from the average molar masses and molar mass distributions measured by size exclusion chromatography (SEC) with online multiangle light scattering and refractive index detection. Methylated cellooligosaccharides with degrees of polymerization (DP) between 1 and 6 formed during hydrolysis were analyzed by direct infusion electrospray ionization ion-trap mass spectrometry (ESI-ITMS). Mass spectra of microIMER- and batch-hydrolyzed samples were compared and no significant differences were found, indicating that microIMER hydrolysis was as efficient as conventional batch hydrolysis. A fast and automated hydrolysis with online MS detection was achieved by connecting the microIMER to high-performance liquid chromatography and ESI-ITMS. This online separation reduced the relative intensities of interfering signals and increased the signal-to-noise ratios in MS. The microIMER hydrolysates were also subjected to SEC interfaced with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. With this technique, oligomers with DP 3-30 could be detected. The hydrolysis by the microIMER was performed within 60 min, i.e. significantly faster compared with batch hydrolysis usually performed for at least 24 h. The microIMER also allowed hydrolysis after 10 days of continuous use. The method presented in this work offers new approaches for the analysis of derivatized cellulose and provides the possibility of convenient online, fast, and more versatile analysis compared with the traditional batch method.     

A multi-one-class dynamic classifier for adaptive digitization of document streams

In this paper, we present a new dynamic classifier design based on a set of one-class independent SVM for image data stream categorization. Dynamic or continuous learning and classification has been recently investigated to deal with different situations, like online learning of fixed concepts, learning in non-stationary environments (concept drift) or learning from imbalanced data. Most of solutions are not able to deal at the same time with many of these specificities. Particularly, adding new concepts, merging or splitting concepts are most of the time considered as less important and are consequently less studied, whereas they present a high interest for stream-based document image classification. To deal with that kind of data, we explore a learning and classification scheme based on one-class SVM classifiers that we call mOC-iSVM (multi-one-class incremental SVM). Even if one-class classifiers are suffering from a lack of discriminative power, they have, as a counterpart, a lot of interesting properties coming from their independent modeling. The experiments presented in the paper show the theoretical feasibility on different benchmarks considering addition of new classes. Experiments also demonstrate that the mOC-iSVM model can be efficiently used for tasks dedicated to documents classification (by image quality and image content) in a context of streams, handling many typical scenarii for concepts extension, drift, split and merge.     

Uncertainty visualization in medical volume rendering using probabilistic animation

Direct Volume Rendering has proved to be an effective visualization method for medical data sets and has reached wide-spread clinical use. The diagnostic exploration, in essence, corresponds to a tissue classification task, which is often complex and time-consuming. Moreover, a major problem is the lack of information on the uncertainty of the classification, which can have dramatic consequences for the diagnosis. In this paper this problem is addressed by proposing animation methods to convey uncertainty in the rendering. The foundation is a probabilistic Transfer Function model which allows for direct user interaction with the classification. The rendering is animated by sampling the probability domain over time, which results in varying appearance for uncertain regions. A particularly promising application of this technique is a "sensitivity lens" applied to focus regions in the data set. The methods have been evaluated by radiologists in a study simulating the clinical task of stenosis assessment, in which the animation technique is shown to outperform traditional rendering in terms of assessment accuracy.     

Resources contributing to gaining competitive advantage for open source software projects: An application of resource-based theory

Open Source Software (OSS) is an important asset in today's software-intensive society. The success of OSS projects is highly dependent on a number of factors. These factors must be understood and managed as an OSS project progresses. Thus, project management of an OSS project has a decisive role in ensuring the success of its software. The objective of the research is to increase the understanding of the resources affecting the competitiveness of OSS projects. Herewith, the responsiveness of OSS projects to users' needs is assessed via an investigation of the defect-fixing process. A Resource-Based View of the firm (RBV) is used to build theoretical justifications for a set of hypotheses proposed in this study. Data gathered from 427 OSS projects confirmed that developers' interest in and users' contribution to the project as well as frequently updating and releasing the software affect the project's ability to gain competitive advantage through effective defect-fixing. It is also shown that OSS projects that are more popular and have a higher level of organizational communication than others are more likely to gain competitive advantage through effective defect-fixing. Finally, implications of the results for practitioners and the research community are presented.     

Gas-Sensing Properties of Nanocrystalline WO3 Films Made by Advanced Reactive Gas Deposition

Nanocrystalline WO₃ films were produced by advanced reactive gas deposition onto alumina substrates. The as-deposited films had a tetragonal crystal structure and a mean grain size of around 6 nm, as found by X-ray diffraction and electron microscopy. Sintering at a temperature τ_s > 770 K yielded monoclinic films. We investigated the gas-sensing properties of films sintered up to 870 K. After an initial "activation" at τ_s= 750 K, the nanocrystalline WO₃ films showed excellent gas-sensing properties, even at room temperature, on exposure to low concentrations of H₂S in air. As little as 10 ppm of H₂S made the conductance increase by a factor of about 10³ within 10 min. The initial properties could be restored by heating the films to 530 K for 1 min.