Beam quality improvement of high-power semiconductor lasers using laterally inhomogeneous waveguides

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 113, 221107 (2018) and may be found at https://doi.org/10.1063/1.5054645.High-brightness vertical broad-area edge-emitting (HiBBEE) semiconductor lasers in the 1060 nm wavelength range with excellent beam quality in both lateral and vertical directions are presented. An approach to modify the thresholds of the transverse lateral modes of ridge-waveguide (RW) lasers is investigated. It has been experimentally shown that inhomogeneities in both sides of the ridges increase optical losses of the higher-order lateral modes as compared to the fundamental mode. The resulting enhancement in the contrast of the optical losses favors the emission of the fundamental mode and improves the beam quality. Reference RW HiBBEE lasers with a 15 μm wide conventional ridge and a 2.0 mm long cavity provide laterally multi-lateral mode emission which is typical for RW lasers with such wide and homogeneous ridges. On the other hand, RW HiBBEE lasers with triangular-shaped corrugations in both sides of 15 μm wide ridges provide single-lateral mode emission across a wide current range and improve the lateral M2 factor by more than a factor of 2 in the investigated current range. The corrugated RW HiBBEE lasers provide an almost 2 times higher brightness than the reference RW lasers

Ensemble artifact design for context sensitive decision support

Although an improvement of design knowledge is an essential goal of design research, current design research predominantly focuses on knowledge concerning the IT artifact (tool) design process, rather than a more holistic understanding encompassing the dynamic usage contexts of a technological artifact. Conceptualising a design in context as an ensemble artifact (Sein et al., 2011) provides the basis for a more rigorous treatment. This paper describes an IS artifact design framework that has been generated from the development of several practitioner-oriented decision support systems (DSS) in which contextual aspects relevant to practitioners\u27 decision making are considered as integral design themes. We describe five key dimensions of an ensemble artifact design and show their value in designing practitioner-oriented DSS. The features are user centredness, knowledge sharing, situation-specific customisation, reduced model orientation, and practice based secondary design abilities. It is argued that this understanding can contribute to design research knowledge more effectively both to develop dynamic DSS, and by its extensibility to other artifact designs

A Socio-technical Approach to Designing and Evaluating Industry Oriented Applications

Over the past few years many views have emerged that maximize the utilization of design research in Information Systems (IS) application development. A recent insightful debate in the IS community has suggested two major design views in IS research: a) a pragmatic technical artifact orientation, and b) a theory-grounded user and meta-artifact focus. The first (pragmatic design-based) view focuses on explicit knowledge and on a step-by-step methodology for innovative artifact design and building. The second (theory-grounded) view more broadly emphasizes meta-artifact design in IS development and a more prescriptive guidance approach that is grounded in design research. The debate between these two views leads to the question: which method is more suitable for Decision Support System (DSS) design? In extending the debate on design views in IS research, this paper evaluates a DSS application through both the utility of the pragmatic and the socio-technical design research views. This helps create a methodological foundation for industry-oriented DSS design and evaluation. The findings suggest that both positions have merit, but the latter view of design science is more suitable for industry-oriented DSS design

A Metadesign Theory for Tailorable Decision Support

Despite years of decision support systems (DSS) research, DSS artifacts are frequently criticized for lacking practitioner relevance and for neglecting configurability and contextual dynamism. Tailoring in end-user contexts can produce relevant emergent DSS artifacts, but design theory for this is lacking. Design science research (DSR) has important implications for improving DSS uptake, but generally this has not been promoted in the form of metadesigns with design principles applicable to other DSS developments. This paper describes a metadesign theory for tailorable DSS, generated through action design research studies in different primary industries. Design knowledge from a DSS developed in an agricultural domain was distilled and generalized into a design theory comprising: (1) a general solution concept (metadesign), and (2) five hypothesized design principles. These were then instantiated via a second development in which the metadesign and design principles were applied in a different domain (forestry) to produce a successful DSS, thus testing the metadesign and validating the design principles. In addition to contributing to DSR and illustrating innovation in tailorable technology, the paper demonstrates the utility of action design research to support theory development in DSS design

A Location Analytics Method for the Utilisation of Geotagged Photos in Travel Marketing Decision-Making

© 2019 World Scientific Publishing Co. Location analytics offers statistical analysis of any geo-or spatial data concerning user location. Such analytics can produce useful insights into the attractions of interest to travellers or visitation patterns of a demographic group. Based on these insights, strategic decision-making by travel marketing agents, such as travel package design, may be improved. In this paper, we develop and evaluate an original method of location analytics to analyse travellers\u27 social media data for improving managerial decision support. The method proposes an architectural framework that combines emerging pattern data mining techniques with image processing to identify and process appropriate data content. The design artefact is evaluated through a focus group and a detailed case study of Australian outbound travellers. The proposed method is generic, and can be applied to other specific locations or demographics to provide analytical outcomes useful for strategic decision support

A Decision support framework for public healthcare: An approach to follow-up support service

© ACIS 2017. Healthcare service systems require care follow-up procedures using clinical practice guidelines targeting specific patient groups. Studies have introduced various methods for providing patient care, but system design for follow-up support remains limited to a few specific types of disease management. A general need is identified in a climate of increased demand on fewer doctors, for which mobile systems can provide solutions. In this paper, we present a post-treatment follow-up Decision Support framework for use by patients and physicians. The proposed care support is cloud-based and offers online and asynchronous Patient-Physician interaction, with a ratings system designed to ensure continuing improvement in outcomes. Using a design science research process the solution framework has been prototyped and evaluated with representative physicians and users. Our framework provides a model for extending care service systems to inform better follow-up decision-making

Locating NAPLs in Ground Water Using Partitioning Fluorescent Dyes

A major challenge in ground water remediation is locating nonaqueous phase liquids (NAPLs). Partitioning tracers can be used to identify NAPL sources between injection and extraction wells. NAPLs are only slightly soluble in water, pose a long-term source of groundwater contamination, and can be difficult to remove. The complexity of recovery processes requires the development of new technologies that guarantee cost effective methods for locating and quantifying NAPLs. Traditional methods like soil coring have been inefficient since they underestimate the quantity of NAPLs and are expensive. Partitioning tracer tests are some of the most recent methods developed for locating these contaminants and determining the volume of the NAPL present in the inter-well zone. The results of the tests can be used to develop remediation techniques to recover NAPLs entrapped in the contaminated zone. Fluorescent dyes may be useful as partitioning tracers. They can be analyzed quickly at the field site, resulting in a shorter analysis time and lower costs than other partitioning tracers. This project pursued the selection of suitable tracers and the development of partitioning tracer techniques to locate and quantify NAPLs in the subsurface

The ‘caged torch procession’: Celebrities, protesters and the 2008 Olympic torch relay in London, Paris and San Francisco

Along with the opening and closing ceremonies, one of the major non-sports events associated with the modern Olympic Games is the torch relay. Although initiated in 1936, the relay has been subject to relatively little academic scrutiny. The events of April 2008 however will have cast a long shadow on the practice. This essay focuses primarily on one week (6–13 April) in the press coverage of the 2008 torch relay as the flame made its way from London to Paris in Europe and then to San Francisco in the USA. It discusses the interpretations offered in the mediated coverage about the relay, the Olympic movement, the host city and the locations where the relay was taking place, and critically analyses the role of agencies, both for and against the Olympics, that framed the ensuing debate

Electron-Spin Precession in Dependence of the Orientation of the External Magnetic Field

Electron-spin dynamics in semiconductor-based heterostructures has been investigated in oblique magnetic fields. Spins are generated optically by a circularly polarized light, and the dynamics of spins in dependence of the orientation (θ) of the magnetic field are studied. The electron-spin precession frequency, polarization amplitude, and decay rate as a function ofθare obtained and the reasons for their dependences are discussed. From the measured data, the values of the longitudinal and transverse components of the electrong-factor are estimated and are found to be in good agreement with those obtained in earlier investigations. The possible mechanisms responsible for the observed effects are also discussed