Higher Quality Requirements: Supporting Joint Application Development with the Nominal Group Technique

Miscommunication among systems developers and users has plagued systems requirements determination under conventional approaches and has contributed to several systems failures. Joint Application Development (JAD) was introduced to alleviate this problem by bringing together developers, users, and managers in face-to-face workshops designed to produce higher quality requirements. However, JAD sessions are conducted under the freely interacting group structure, which makes them susceptible to many of the classical problems commonly encountered during group deliberations. In this paper we present a case for integrating JAD and the nominal group technique (NGT), a group protocol that was designed to solve problems similar to those encountered in JAD. We tested our proposition in a laboratory experiment consisting of 24 group sessions, in which professional JAD facilitators led a diverse group of business professionals, managers, and advanced business students in specifying high-level requirements (under JAD and with the integrated techniques) for a simulated IS problem. The neutral and objective measures of their effects on the quality of the resulting requirements indicate that the combination of these group process structures seems to neutralize the negative impacts of group dynamics often experienced in JAD sessions, and contributes to improvements in the quality of the requirements.     

Philosophical commitments and therapy approach preferences among psychotherapy trainees.

Examined the role of philosophical beliefs in psychotherapy approach preference. It was hypothesized that trainees would prefer approaches that most closely correspond to their personal philosophical beliefs. 59 students (median age 27 yrs) were given audiotaped presentations. Three dimensions of the Ss' philosophical commitments (ontological, epistemological and causal) were examined in relation to their relative preferences for 3 therapy approaches: rationalist, constructivist and behavioral. Results show that Ss tended to prefer a specific approach that most corresponded to their own ontological, epistemological and causal commitments. This suggests a role for philosophical beliefs in therapists' preferences for different theoretical orientations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of riparian vegetation on water quality in a mixed land use river basin

Worldwide, agricultural activities are associated with environmental impacts including riparian degradation and increased waterway pollution. The Fitzroy Basin of Central Queensland lies within the Brigalow Belt Bioregion, which is currently experiencing the highest rates of tree clearing in Australia driven by grazing activities, and this is likely to increase riparian degradation. Local riparian condition, however, has not been consistently monitored within the Fitzroy Basin, and its relationship with water quality has not been well established. This study assessed riparian condition of waterways in the Fitzroy Basin using two established scoring methods (the Rapid Appraisal of Riparian Condition and the Australian Rivers Assessment System Habitat Assessment) and statistically investigated the relationship between stream water quality and local riparian condition. Twelve sites in six waterways were sampled four times over two years, during ambient (nonflood) conditions. Upstream creeks with poorer riparian condition had elevated dissolved organic carbon (DOC), dissolved manganese, sulfate, and total nitrogen (TN) concentrations. High concentrations of these water quality variables were associated with poor local riparian scores in principal components analysis. Dissolved manganese and sulfate were included in the multiple regression model for riparian scores (r values: 0.83 to 0.86; p < 0.001), and DOC and TN were very significantly negatively correlated with riparian scores (r values: ?0.55 to ?0.69; p < 0.001). Overall, the results suggest that protecting riparian vegetation in the Fitzroy Basin and restoring degraded riparian zones could aid in improving water quality in waterways within this region.     

The ARTEMIS under‐ice AUV docking system

The ARTEMIS docking system demonstrates autonomous docking capability applicable to robotic exploration of sub‐ice oceans and sub‐glacial lakes on planetary bodies, as well as here on Earth. In these applications, melted or drilled vertical access shafts restrict vehicle geometry as well as the in‐water infrastructure that may be deployed. The ability of the vehicle to return reliably and precisely to the access point is critical for data return, battery charging, and/or vehicle recovery. This paper presents the mechanical, sensor, and software components that make up the ARTEMIS docking system, as well as results from field deployment of the system to McMurdo Sound, Antarctica in the austral spring of 2015. The mechanical design of the system allows the vehicle to approach the dock from any direction and to pitch up after docking for recovery through a vertical access shaft. It uses only a small volume of in‐water equipment and may be deployed through a narrow vertical access shaft. The software of the system reduces position estimation error with a hierarchical combination of dead reckoning, acoustic aiding, and machine vision. The system provides critical operational robustness, enabling the vehicle to return autonomously and precisely to the access shaft and latch to the dock with no operator input.     

Autonomous Exploration with Exact Inverse Sensor Models

This paper is focused on probabilistic occupancy grid mapping and motion planning such that a robot may build a map and explore a target area autonomously in real time. The desired path of the robot is developed in an optimal fashion to maximize the information gain from the sensor measurements on its path, thereby increasing the accuracy and efficiency of mapping, while explicitly considering the sensor limitations such as the maximum sensing range and viewing angle. Most current exploration techniques require frequent human intervention, often developed for omnidirectional sensors with infinite range. The proposed research is based on realistic assumptions on sensor capabilities. The unique contribution is that the mapping and autonomous exploration techniques are systematically developed in a rigorous, probabilistic formulation. The mapping approach exploits the probabilistic properties of the sensor and map explicitly, and the autonomous exploration is designed to maximize the expected map information gain, thereby improving the efficiency of the mapping procedure and the quality of the map substantially. The efficacy of the proposed optimal approach is illustrated by both numerical simulations and experimental results.     

Overproduction and purification of the regulatory subunit of Escherichia coli aspartate transcarbamoylase

An Escherichia coli strain/plasmid system has been developedfor the overexpression of the regulatory subunit of E.coli aspartatetranscarbamoylase (ATCase). Production of large quantities ofregulatory subunit, by the method described here, should facilitatefuture experiments, such as X-ray crystallography, NMR and hybridizationexperiments, aimed at understanding the heterotropic mechanismthat regulates the activity of ATCase. The plasmid used forthe over-expression carries the gene for the regulatory subunit,pyrI, downstream from the strong pyrB promoter. The host strain,EK1104 [Nowlan, S.F. and Kantrowitz, E.R. (1985) J. Biol. Chem.,260, 14712–14716] carries a deletion in the pyrBI regionof the chromosome, as well as a leaky pyrF allele. When thisstrain/plasmid system is grown under limiting pyrimidine levels,large quantities of the regulatory subunit of ATCase are producedwithout any trace of catalytic subunit or holo-enzyme. A procedurefor the purification of the regulatory subunit from cell extractshas also been developed yielding {small tilde}50 mg of purifiedregulatory subunit per liter of initial culture. The regulatorysubunit produced in this fashion is fully competent in reassociationexperiments with the native catalytic subunit. Furthermore,the reassociated holoenzyme exhibits kinetic properties identicalto those of the wild type enzyme. In addition, we report theconstruction of a pUC119 based plasmid which carries a uniqueNdeI site at the fMet of the pyrB gene of ATCase. This plasmid,which was used in the construction of the system for the overexpressionof the regulatory subunit of ATCase, has been shown to be ofgeneral use for the expression of foreign proteins in E.coli.     

Multi-layer atom chips for atom tunneling experiments near the chip surface

This paper describes the design and fabrication of an atom chip to be used in ultra-high-vacuum cells for cold-atom tunneling experiments. A fabrication process was developed to pattern micrometer- and nanometer-scale copper wires onto a single chip. The wires, with fabricated widths down to 200 nm, can sustain current densities of more than 7.5 × 10⁷ A/cm². Partially suspended wires, developed in order to reduce the Casimir–Polder force between atoms and surface, were also fabricated and tested. Extensive measurements for variable wire width show that the sustainable currents are sufficiently large to allow chip-based atom tunneling experiments. Such chips may allow the realization of an atom transistor.     

Effect of multiplicative noise on least-squares parameter estimation with applications to the atomic force microscope

Measurement of the power spectral density of (stochastic) Brownian fluctuations of micro- and nano-devices is used frequently to gain insight into their mechanistic properties. Noise is always present in these measurements and can directly influence any parameter estimation obtained through a least-squares analysis. Importantly, measurements of the spectral density of stationary random signals, such as Brownian motion, inherently contain multiplicative noise. In this article, we theoretically analyze the impact of multiplicative noise on fit parameters extracted using a least-squares analysis. A general analysis is presented that is valid for any fit function with any number of fit parameters. This yields closed-form expressions for the expected value and variance in the fit parameters and provides a rigorous theoretical framework for a priori determination of the effect of measurement uncertainty. The theory is demonstrated and validated through Monte Carlo simulation of synthetic data and by comparison to power spectral density measurements of the Brownian fluctuations of an atomic force microscope cantilever - analytical formulas for the uncertainty in the fitted resonant frequency and quality factor are presented. The results of this study demonstrate that precise measurements of fit parameters in the presence of noise are inherently problematic - individual measurements of the power spectral density are capable of yielding fit parameters that are many standard deviations away from the mean, with finite probability. This is of direct relevance to a host of applications in measurement science, including those connected with the atomic force microscope.     

Residence Time Distribution and Specific Mechanical Energy in Solid-State Shear Pulverization: Processing-Structure-Property Relationships in a Chilled Extruder

Solid-state shear pulverization (SSSP) is a continuous polymer processing methodology based on a modified twin-screw extruder. The unique application of low barrel temperatures and mechanochemistry has contributed to the development of an extensive range of polymer-based materials, from environmentally responsible polymer blends to nanocomposites, for more than 30 years. The complex processing-structure-processing relationships in SSSP can be elucidated by way of integrated, measured covariants that capture the interplay between numerous processing parameters. Residence time distribution and specific mechanical energy are evaluated in a base case polypropylene (PP) study under a full factorial experiment involving screw design, screw speed, and throughput parameters. These factors are in turn correlated to dispersion morphology and thermal property results from a parallel study based on a model PP/carbon black composite. This investigation highlights the tunability of SSSP processing parameters for tailored output with desired purposes and applications. In particular, enhanced residence distribution can be achieved with low screw speed and high throughput settings, leading to high levels of material mixing and shear. POLYM. ENG. SCI., 60:503–511, 2020. © 2019 Society of Plastics Engineers