A taxonomy of asymmetric requirements aspects

The early aspects community has received increasing attention among researchers and practitioners, and has grown a set of meaningful terminology and concepts in recent years, including the notion of requirements aspects. Aspects at the requirements level present stakeholder concerns that crosscut the problem domain, with the potential for a broad impact on questions of scoping, prioritization, and architectural design. Although many existing requirements engineering approaches advocate and advertise an integral support of early aspects analysis, one challenge is that the notion of a requirements aspect is not yet well established to efficaciously serve the community. Instead of defining the term once and for all in a normally arduous and unproductive conceptual unification stage, we present a preliminary taxonomy based on the literature survey to show the different features of an asymmetric requirements aspect. Existing approaches that handle requirements aspects are compared and classified according to the proposed taxonomy. In addition,we study crosscutting security requirements to exemplify the taxonomy's use, substantiate its value, and explore its future directions

Requirements engineering and continuous deployment

This article summarizes the RE in the Age of Continuous Deployment panel at the 25th IEEE International Requirements Engineering Conference. It highlights two synergistic points (user stories and linguistic tooling) and one challenge (nonfunctional requirements) in fast-paced, agile-like projects, and recommends how to carry on the dialogue.Peer ReviewedPostprint (author's final draft

GaN/InGaN Microcavities and Applications

Semiconductor micro- and nano-cavities are excellent platforms for experimental studies of optical cavities, lasing dynamics, and cavity Quantum Electrodynamics (QED). Common materials for such experiments are narrow bandgap semiconductor materials with well-developed epitaxial growth technologies, such as GaAs and InP, among others. Gallium nitride (GaN) and its alloys are industrially viable materials with wide direct bandgaps, low surface re-combination velocities, and large exciton binding energies, offering the possibility of room temperature realization of light-matter interaction. Controlling light-matter interaction is at the heart of nanophotonic research which leads to ultra-low threshold lasing, photonic qubits, and optical strong coupling. Technologically, due to its blue emission, GaN photonic cavities with indium gallium nitride (InGaN) active mediums serve as efficient light sources for the fast growing photonic industry, optical computing and communication networks, display technology, as well as quantum information processing. The main challenges in fabricating high quality GaN cavity are due to its chemical inertness and low material quality as a result of strain-induced defects and threading dislocations. In this dissertation, I examine the designs, novel fabrication processes, and characterizations of high quality factor GaN microdisk and photonic crystal nanobeam cavities with different classes of InGaN active medium, namely quantum dots (QDs), quantum wells (QWs), and fragmented quantum wells (fQWs), for investigating light-matter interaction between cavity and these active media. This dissertation is carefully organized into four chapters. Chapter 1 outlines the background of the research, the materials and growth, and the necessary technique Photoelectrochemical (PEC) etching which is uniquely used to undercut and suspend GaN cavities. Chapter 2 outlines the fabrications, optical experiments, and tuning technique developed for GaN/InGaN microdisks. Microdisks are circular resonant cavities that support whispering gallery modes. Through the use of optimized dry etching and PEC, high quality factor microdisks with relatively small modal volume are fabricated with immediate demonstration of low threshold lasing. On the path to achieving light and matter interactions, irreversible tuning of the cavity mode of p-i-n doped GaN/InGaN microdisks is achieved through photo-excitation in a water environment. Such a technique paves the way for deterministically and spectrally matching the cavity mode to the emitter’s principle emission. Chapter 3 outlines the work done on the high quality GaN photonic crystal nanobeams with InGaN QDs and fQWs. The fragmented nature of the fQW layer has a surprisingly dramatic influence on the lasing threshold. A record low threshold is demonstrated that is an order of magnitude lower in threshold than identical nanobeams with homogeneous QW, and comparable to the best devices in other III-V material systems. As an active medium with greater carrier confinement than quantum wells, and higher carrier capture probability than quantum dots, the fQW active medium, in combination with the nanobeam cavity with ultra-small modal volume and high quality factor, provides an ideal means of probing the limits of light and matter interactions in the nanoscale. Moreover, GaN/InGaN nanopillars are fabricated to isolate a single InGaN QD for understanding its emission properties. Antibunching is observed, demonstrating the quantum nature of the QD emission. Gas tuning is attempted on GaN nanobeams with InGaN QDs to achieve QD-cavity mode coupling and to demonstrate cavity enhanced single photon emission. Last but not least, Chapter 4 concludes the dissertation with summary and future directions.Engineering and Applied Sciences - Applied Physic

3D shape measurement of discontinuous specular objects based on advanced PMD with bi-telecentric lens

This paper presents an advanced phase measuring deflectometry (PMD) method based on a novel mathematical model to obtain three dimensional (3D) shape of discontinuous specular object using a bi-telecentric lens. The proposed method uses an LCD screen, a flat beam splitter, a camera with a bi-telecentric lens, and a translating stage. The LCD screen is used to display sinusoidal fringe patterns and can be moved by the stage to two different positions along the normal direction of a reference plane. The camera captures the deformed fringe patterns reflected by the measured specular surface. The splitter realizes the fringe patterns displaying and imaging from the same direction. Using the proposed advanced PMD method, the depth data can be directly calculated from absolute phase, instead of integrating gradient data. In order to calibrate the relative orientation of the LCD screen and the camera, an auxiliary plane mirror is used to reflect the pattern on the LCD screen three times. After the geometric calibration, 3D shape data of the measured specular objects are calculated from the phase differences between the reference plane and the reflected surface. The experimental results show that 3D shape of discontinuous specular object can be effectively and accurately measured from absolute phase data by the proposed advanced PMD method

Research Toward a Partially-Automated, and Crime Specific Digital Triage Process Model

The digital forensic process as traditionally laid out begins with the collection, duplication, and authentication of every piece of digital media prior to examination. These first three phases of the digital forensic process are by far the most costly. However, complete forensic duplication is standard practice among digital forensic laboratories. The time it takes to complete these stages is quickly becoming a serious problem. Digital forensic laboratories do not have the resources and time to keep up with the growing demand for digital forensic examinations with the current methodologies. One solution to this problem is the use of pre-examination techniques commonly referred to as digital triage. Pre-examination techniques can assist the examiner with intelligence that can be used to prioritize and lead the examination process. This work discusses a proposed model for digital triage that is currently under development at Mississippi State University