Towards Product Lining Model-Driven Development Code Generators

A code generator systematically transforms compact models to detailed code. Today, code generation is regarded as an integral part of model-driven development (MDD). Despite its relevance, the development of code generators is an inherently complex task and common methodologies and architectures are lacking. Additionally, reuse and extension of existing code generators only exist on individual parts. A systematic development and reuse based on a code generator product line is still in its infancy. Thus, the aim of this paper is to identify the mechanism necessary for a code generator product line by (a) analyzing the common product line development approach and (b) mapping those to a code generator specific infrastructure. As a first step towards realizing a code generator product line infrastructure, we present a component-based implementation approach based on ideas of variability-aware module systems and point out further research challenges.Comment: 6 pages, 1 figure, Proceedings of the 3rd International Conference on Model-Driven Engineering and Software Development, pp. 539-545, Angers, France, SciTePress, 201

Proactive Quality Guidance for Model Evolution in Model Libraries

Model evolution in model libraries differs from general model evolution. It limits the scope to the manageable and allows to develop clear concepts, approaches, solutions, and methodologies. Looking at model quality in evolving model libraries, we focus on quality concerns related to reusability. In this paper, we put forward our proactive quality guidance approach for model evolution in model libraries. It uses an editing-time assessment linked to a lightweight quality model, corresponding metrics, and simplified reviews. All of which help to guide model evolution by means of quality gates fostering model reusability.Comment: 10 pages, figures. Appears in Models and Evolution Workshop Proceedings of the ACM/IEEE 16th International Conference on Model Driven Engineering Languages and Systems, Miami, Florida (USA), September 30, 201

Mueller Matrix Microscopy for In Vivo Scar Tissue Diagnostics and Treatment Evaluation

Scars usually do not show strong contrast under standard skin examination relying on dermoscopes. They usually develop after skin injury when the body repairs the damaged tissue. In general, scars cause multiple types of distress such as movement restrictions, pain, itchiness and the psychological impact of the associated cosmetic disfigurement with no universally successful treatment option available at the moment. Scar treatment has significant economic impact as well. Mueller matrix polarimetry with integrated autofocus and automatic data registration can potentially improve scar assessment by the dermatologist and help to make the evaluation of the treatment outcome objective. Polarimetry can provide new physical parameters for an objective treatment evaluation. We show that Mueller matrix polarimetry can enable strong contrast for in vivo scar imaging. Additionally, our results indicate that the polarization stain images obtained form there could be a useful tool for dermatology. Furthermore, we demonstrate that polarimetry can be used to monitor wound healing, which may help prevent scarring altogether

Wavefront shaping concepts for application in optical coherence tomography - a review

Optical coherence tomography (OCT) enables three-dimensional imaging with resolution on the micrometer scale. The technique relies on the time-of-flight gated detection of light scattered from a sample and has received enormous interest in applications as versatile as non-destructive testing, metrology and non-invasive medical diagnostics. However, in strongly scattering media such as biological tissue, the penetration depth and imaging resolution are limited. Combining OCT imaging with wavefront shaping approaches significantly leverages the capabilities of the technique by controlling the scattered light field through manipulation of the field incident on the sample. This article reviews the main concepts developed so far in the field and discusses the latest results achieved with a focus on signal enhancement and imaging. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Double Interferometer Design for Independent Wavefront Manipulation in Spectral Domain Optical Coherence Tomography

Spectral domain optical coherence tomography (SD-OCT) is a highly versatile method which allows for three dimensional optical imaging in scattering media. A number of recent publications demonstrated the technique to benefit from structured illumination and beam shaping approaches, e.g. to enhance the signal-to-noise ratio or the penetration depth with samples such as biological tissue. We present a compact and easy to implement design for independent wavefront manipulation and beam shaping at the reference and sample arm of the interferometric OCT device. The design requires a single spatial light modulator and can be integrated to existing free space SD-OCT systems by modifying the source arm only. We provide analytical and numerical discussion of the presented design as well as experimental data confirming the theoretical analysis. The system is highly versatile and lends itself for applications where independent phase or wavefront control is required. We demonstrate the system to be used for wavefront sensorless adaptive optics as well as for iterative optical wavefront shaping for OCT signal enhancement in strongly scattering media. © 2019, The Author(s)

Evaluation of polymer-based eccentric FBG bending sensor for humidity, strain, temperature and torsion

We analyse and evaluate the sensitivity and robustness of an eccentric fiber Bragg grating sensor micro-structured into a polymer optical fiber under different relative humidity, temperature, strain and torsion conditions. Relative humidity and temperature conditions are established with a climate test chamber and prepared salt solutions. Though made of polymer, the cross-sensitivity of the sensor to relative humidity is low, enabling usage in rapidly changing environment applications, e.g., for movement detecting gloves or in vehicles, but also in high moisture situations. We find a linear dependence on temperature, so that either bending or temperature can be measured separately from each other. After rotation of one end, the sensor measures torsion by observing the light intensity and the change of the full width at half maximum. Strain measurement shows multiple elastic strain regions before final plastic deformations occur. In the next step, the flexible sensor system will be implemented in a sensor glove to monitor finger movement and detect different hand gestures

Improved polarimetric analysis of human skin through stitching: advantages, limitations, and applications in dermatology

Polarimetry is a powerful tool for the analysis of the optical properties of materials and systems, such as human skin. However, in many polarimetric setups, the field of view is limited to a few square centimeters. In these cases, it is possible to resort to stitching techniques, which involve combining multiple Mueller matrix measurements obtained from different overlapping regions of the sample. In this paper, we propose a stitching technique for polarimetric data and discuss its advantages and limitations. We also describe the potential of image stitching for improving the accuracy and robustness of in vivo polarimetry in the presence of random patient movement. We conducted our research using a diverse set of samples which included porcine skin, human skin from arms and fingers, cold cuts of chicken and gelatine, alongside synthetically created sample data. Our results demonstrate the effectiveness of this technique for the application in dermatology. Each additional in vivo measurement enhances the field of view by approximately one third, thereby considerably augmenting the total observation area. We show that stitching enables for the polarimetric assessment of large skin patches which is useful for the diagnosis of inflammatory skin diseases

Lighting with laser diodes

Contemporary white light-emitting diodes (LEDs) are much more efficient than compact fluorescent lamps and hence are rapidly capturing the market for general illumination. LEDs are also replacing halogen lamps or even newer xenon based lamps in automotive headlamps. Because laser diodes are inherently much brighter and often more efficient than corresponding LEDs, there is great research interest in developing laser diode based illumination systems. Operating at higher current densities and with smaller form factors, laser diodes may outperform LEDs in the future. This article reviews the possibilities and challenges in the integration of visible laser diodes in future illumination systems. © 2013 Thoss Media & De Gruyter