Factors influencing feature usage in work-related communication

Two studies are presented. The first aimed to identify possible barriers to the uptake and use of commonly available telephony features and to determine whether greater knowledge of features/access codes and availability of user manuals could increase feature usage under certain conditions. Results showed that feature-usage patterns were not affected by any of the manipulations, but that they were determined by specific job demands. Using Constantine and Lockwood's (1999) conceptualization of user roles, a method to support feature bundling decisions for specific target markets was developed and tested in the second study. The method - Strategic User Needs Analysis (SUNA) - was shown to yield a useful balance between high- and low-level information about selected roles. SUNA provided sufficient information to distinguish between PDA feature usage patterns of two similar target user groups as well as to suggest additional features each of the two target groups would find useful. The development of SUNA and observational findings of actual PDA usage are reported.     

The MITRE E3 family of models structure and results

A family of energy/economic/environmental (E³) models is presented as a mechanism for analysing national policy issues. The family consists of discrete models which are designed to be run in an integrated manner. The outputs of certain models provide the inputs to the next. This structure allows the analyst to readily incorporate an understanding of regional factors such as local energy prices, concerns over air quality, water availability, or attitudes towards construction of new energy facilities, into national assessments of energy policies. This paper reviews the analytic framework within which energy policy issues are currently addressed. The initial family of E³ models is described with the emphasis on the data linkages and feedback which are provided when these models are run sequentially. The ongoing MITRE research programme with the E³ family of models is presented and plans and opportunities for future work are outlined.     

The isolated air perfused rat heart

A simple method has been developed for continuous monitoring of metabolic activity of an isolated, perfused rat heart by O2/CO2 respirometer. Since respirometer provides vital data on oxygen consumption and carbon dioxide production of a preserved organ on a continuous basis over a long period of time, it will be possible to use this method to monitor viability of not only isolated heart but also any given donor organ under preservation.     

Model-Based Diagnosis of Hybrid Systems

Techniques for diagnosing faults in hybrid systems that combine digital (discrete) supervisory controllers with analog (continuous) plants need to be different from those used for discrete or continuous systems. This paper presents a methodology for online tracking and diagnosis of hybrid systems. We demonstrate the effectiveness of the approach with experiments conducted on the fuel-transfer system of fighter aircraft     

Potent and selective bicyclic lactam inhibitors of thrombin: Part 2: P1 modifications

The synthesis and antithrombotic activity of a series of nonpeptide bicyclic thrombin inhibitors is described. We have explored the SAR with modifications to the P1 site. The introduction of arginine mimetics at the P1 site led to potent and selective thrombin inhibitors.     

Mathematical and Scientific Foundations for an Integrative Engineering Curriculum

All fields of engineering, whether chemical, civil, electrical, materials, mechanical, etc., encompass a common body of essential mathematics and science. In the freshman year of Drexels E⁴ program, this common mathematical and scientific foundation is cultivated in the Mathematical and Scientific Foundations of Engineering I, II and III (MSFE I, MSFE II, MSFE III). In an integrated fashion, MSFE I presents the essential calculus, physics and engineering mechanics vital to the freshman engineering student. In the first two quarters, MSFE II presents chemistry with clearly defined engineering applications and significance: in the third quarter, MSFE II presents living systems with the same thrust. Also in the third quarter, MSFE III presents basic circuits and circuit elements, and a brief introduction to electromagnetic theory.     

An investigation of the ordered DO19 phase formation in the Ti-Al system

For the Ti-rich, Ti-AI system, the- and- ₂ phase boundaries have been obtained through differential thermal analysis for alloy compositions ranging from 10.2 to 25.2 at% Al (6 to 16 wt% Al). It has been shown that in the above mentioned composition range, a metastable disordered-phase can be quenched in. This metastable then transforms to the ordered ₂(DO)₁₉ phase upon heating and/or isothermal ageing. It has also been observed that the kinetics of this ordering phenomenon is composition dependent.     

Appearance Derivatives for Isonormal Clustering of Scenes

A new technique is proposed for scene analysis, called "appearance clustering.” The key result of this approach is that the scene points can be clustered according to their surface normals, even when the geometry, material, and lighting are all unknown. This is achieved by analyzing an image sequence of a scene as it is illuminated by a smoothly moving distant light source. In such a scenario, the brightness measurements at each pixel form a "continuous appearance profile.” When the source path follows an unstructured trajectory (obtained, say, by smoothly hand-waving a light source), the locations of the extrema of the appearance profile provide a strong cue for the scene point's surface normal. Based on this observation, a simple transformation of the appearance profiles and a distance metric are introduced that, together, can be used with any unsupervised clustering algorithm to obtain isonormal clusters of a scene. We support our algorithm empirically with comprehensive simulations of the Torrance-Sparrow and Oren-Nayar analytic BRDFs, as well as experiments with 25 materials obtained from the MERL database of measured BRDFs. The method is also demonstrated on 45 examples from the CURET database, obtaining clusters on scenes with real textures such as artificial grass and ceramic tile, as well as anisotropic materials such as satin and velvet. The results of applying our algorithm to indoor and outdoor scenes containing a variety of complex geometry and materials are shown. As an example application, isonormal clusters are used for lighting-consistent texture transfer. Our algorithm is simple and does not require any complex lighting setup for data collection.     

Unknown input modeling and robust fault diagnosis using black box observers

A key issue that needs to be addressed while performing fault diagnosis using black box models is that of robustness against abrupt changes in unknown inputs. A fundamental difficulty with the robust FDI design approaches available in the literature is that they require some a priori knowledge of the model for unmeasured disturbances or modeling uncertainty. In this work, we propose a novel approach for modeling abrupt changes in unmeasured disturbances when innovation form of state space model (i.e. black box observer) is used for fault diagnosis. A disturbance coupling matrix is developed using singular value decomposition of the extended observability matrix and further used to formulate a robust fault diagnosis scheme based on generalized likelihood ratio test. The proposed modeling approach does not require any a priori knowledge of how these faults affect the system dynamics. To isolate sensor and actuator biases from step jumps in unmeasured disturbances, a statistically rigorous method is developed for distinguishing between faults modeled using different number of parameters. Simulation studies on a heavy oil fractionator example show that the proposed FDI methodology based on identified models can be used to effectively distinguish between sensor biases, actuator biases and other soft faults caused by changes in unmeasured disturbance variables. The fault tolerant control scheme, which makes use of the proposed robust FDI methodology, gives significantly better control performance than conventional controllers when soft faults occur. The experimental evaluation of the proposed FDI methodology on a laboratory scale stirred tank temperature control set-up corroborates these conclusions.     

Comparison of the indentation and elasticity of E. coli and its spheroplasts by AFM

Atomic force microscopy (AFM) provides a unique opportunity to study live individual bacteria at the nanometer scale. In addition to providing accurate morphological information, AFM can be exploited to investigate membrane protein localization and molecular interactions on the surface of living cells. A prerequisite for these studies is the development of robust procedures for sample preparation. While such procedures are established for intact bacteria, they are only beginning to emerge for bacterial spheroplasts. Spheroplasts are useful research models for studying mechanosensitive ion channels, membrane transport, lipopolysaccharide translocation, solute uptake, and the effects of antimicrobial agents on membranes. Furthermore, given the similarities between spheroplasts and cell wall-deficient (CWD) forms of pathogenic bacteria, spheroplast research could be relevant in biomedical research. In this paper, a new technique for immobilizing spheroplasts on mica pretreated with aminopropyltriethoxysilane (APTES) and glutaraldehyde is described. Using this mounting technique, the indentation and cell elasticity of glutaraldehyde-fixed and untreated spheroplasts of E. coli in liquid were measured. These values are compared to those of intact E. coli. Untreated spheroplasts were found to be much softer than the intact cells and the silicon nitride cantilevers used in this study.