Line patterning of graphite and the fabrication of cheap, inexpensive, “throw-away” sensors

A new simple method (“line patterning technique”) using only standard office equipment is described whereby clearly defined, electrically conducting patterns of graphite can be deposited on polymer (plastic) or paper substrates. The properties of the conductive patterns have been characterized by electrical conductivity and SEM measurements. Sensors were constructed by using interdigitated patterns of graphite deposited on plastic and paper, and coated with a thin film of conducting electronic polymer, e.g. polyaniline emeraldine salt.     

Equation of state parameters for stable and non-stable transition metal phases from universal binding Energy relations

Remarkable regularities in the behaviour of the binding energy versus distance function (BEDF) of solids were reported years ago by Rose, Ferrante and Smith (RFS). In various phenomena, such as adhesion, chemisorption and bulk cohesion, it was possible to scale the binding energy and the interatomic distance so that data for various systems could be described by the same, “universal”, binding energy relation (UBER). At the 1995 Ringberg Workshop on Unary Data (Calphad 19 (1995) 538) it was recommended that the RFS approach should be considered as an alternative for correlating and predicting cohesive properties, as well as the parameters of the equation of state of solids (EOS). This possibility has been explored by us, using theoretical information on the energy versus volume relations at zero kelvin, that has been obtained in tight-binding linearized-muffin-tin-orbitals (TB-LMTO) calculations. The cohesive energy, equilibrium volume, bulk modulus and its pressure derivative (B_e′) have been obtained for elements of the second row of the periodic table, viz., Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd and Ag, in the bcc, fcc and hcp structures. With this extensive database a critical test of the hypothesis of “universality” has been carried out. Moreover, the applicability of the RFS approach in predicting B_e′ has been examined. The results for stable phases have been compared with experimental data. Finally, the structure dependence of B_e′ has been discussed, which is a key issue in dealing with the EOS of non-stable structures of the elements.     

Fabrication of high aspect-ratio polymer microstructures for large-area electronic portal x-ray imagers

Megavoltage X-ray imaging performed during radiotherapy is the method of choice for geometric verification of patient localization and dose delivery. Presently, such imaging is increasingly performed using electronic portal imaging devices (EPIDs) based on indirect detection active matrix flat panel imagers (AMFPIs). These devices use a scintillating phosphor screen in order to convert incident X-rays into optical photons, which are then detected by the underlying active matrix photodiode array. The use of a continuous phosphor introduces a trade-off between X-ray quantum efficiency and spatial resolution, which limits current devices to use only 2% of the incident X-rays. This trade-off can be circumvented by “segmented phosphor screens”, comprising a two-dimensional matrix of optically isolated cell structures filled with scintillating phosphor. In this work we describe the fabrication of mm-thick segmented phosphor screens using the MEMS (micro-electro-mechanical-system) polymer SU-8. This method is capable of being extended to large-area substrates.     

Quantum-chemical, NMR and X-ray diffraction studies on (+/-)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane

Time-averaged conformations of (±)-1-[3,4-(methylenedioxy)phenyl]-2-methylaminopropane hydrochloride (MDMA, “ecstasy”) in D₂O, and of its free base and trifluoroacetate in CDCl₃, were deduced from their ¹H NMR spectra and used to calculate their conformer distribution. Their rotational potential energy surface (PES) was calculated at the RHF/6-31G(d,p), B3LYP/6-31G(d,p), B3LYP/cc-pVDZ and AM1 levels. Solvent effects were evaluated using the polarizable continuum model. The NMR and theoretical studies showed that, in the free base, the N-methyl group and the ring are preferentially trans. This preference is stronger in the salts and corresponds to the X-ray structure of the hydrochloride. However, the energy barriers separating these forms are very low. The X-ray diffraction crystal structures of the anhydrous salt and its monohydrate differed mainly in the trans or cis relationship of the N-methyl group to the -methyl, although these two forms interconvert freely in solution.     

A distributed device diagnostics system utilizing augmented reality and 3D audio

Augmented reality (AR), combining virtual environments with the perception of the real world, can be used to provide instructions for routine maintenance and error diagnostics of technical devices. The Rockwell Science Center (RSC) is developing a system that utilizes AR techniques to provide “X-ray vision” into real objects. The system can overlay 3D rendered objects, animations, and text annotations onto the video image of a known object. An automated speech recognition system allows the user to query the status of device components. The response is given as an animated rendition of a CAD model and/or as auditory cues using 3D audio. This diagnostics system also allows the user to leave spoken annotations attached to device modules as ASCII text. The position of the user/camera relative to the device is tracked by a computer-vision-based tracking system using fiducial markers. The system is implemented on a distributed network of PCs, utilizing standard commercial off-the-shelf components (COTS).     

Automatic Word Decompounding for ASR in a Morphologically Rich Language: Application to Amharic

This paper investigates a data-driven word decompounding algorithm for use in automatic speech recognition. An existing algorithm, called “Morfessor,” has been enhanced in order to address the problem of increased phonetic confusability arising from word decompounding by incorporating phonetic properties and some constraints on recognition units derived from forced alignments experiments. Speech recognition experiments have been carried out on a broadcast news task for the Amharic language to validate the approach. The out of vocabulary (OOV) word rates were reduced by 35% to 50% and a small reduction in word error rate (WER) has been achieved. The algorithm is relatively language independent and requires minimal adaptation to be applied to other languages.      

Toward an understanding of the behavioral intention to use mobile banking

Although millions of dollars have been spent on building mobile banking systems, reports on mobile banking show that potential users may not be using the systems, despite their availability. Thus, research is needed to identify the factors determining users' acceptance of mobile banking. While there has been considerable research on the technology acceptance model (TAM) that predicts whether individuals will accept and voluntarily use information systems, limitations of the TAM include the omission of an important trust-based construct in the context of electronic/mobile commerce, and the assumption that there are no barriers preventing an individual from using an IS if he or she chooses to do so. Based on literature relating to the theory of planned behavior (TPB) and the TAM, this study extends the applicability of the TAM in a mobile banking context, by adding one trust-based construct (“perceived credibility”) and two resource-based constructs (“perceived self-efficacy” and “perceived financial cost”) to the model, while paying careful attention to the placing of these constructs in the TAM's existing nomological structure. Data collected from 180 users in Taiwan were tested against the extended TAM, using the structural equation modeling approach. The results strongly support the extended TAM in predicting users' intentions to adopt mobile banking. Several implications for IT/IS acceptance research and mobile banking management practices are discussed.     

Bidirectional calibration results for 11 spectralon and 16 BaSO4 reference reflectance panels

Eleven Spectralon¹ (a sintered polytetrafluoroethylene-based material) and 16 BaSO₄ reference reflectance panels were calibrated using a field calibration technique. The Spectralon panels differed both in their directional/hemispherical and directional/directional reflectance. However, the differences were sufficiently small that “general” calibration equations were developed. For panels constructed of the same material and with the same methods as those used in these experiments, the directional/directional reflectance may be within ± 0.020 at 10°, ± 0.015 at 45°, and ± 0.041 at 80° of that predicted by the “general” equations. For field measurements, these values are considerably better than those that would be obtained using a value of the directional/hemispherical reflectance. The directional/directional reflectance of the 16 BaSO₄ panels varied considerably among panels, so much so that it was not feasible to develop “general” calibration equations. Apparently, the nonlambertian properties of BaSO₄ panels are dependent upon the method of applying the barium sulfate coating.     

The alloy theoretic automated toolkit: A user guide

Although the formalism that allows the calculation of alloy thermodynamic properties from first-principles has been known for decades, its practical implementation has so far remained a tedious process. The Alloy Theoretic Automated Toolkit (ATAT) drastically simplifies this procedure by implementing decision rules based on formal statistical analysis that frees the researchers from a constant monitoring during the calculation process and automatically “glues” together the input and the output of various codes, in order to provide a high-level interface to the calculation of alloy thermodynamic properties from first-principles. ATAT implements the Structure Inversion Method (SIM), also known as the Connolly-Williams method, in combination with semi-grand-canonical Monte Carlo simulations. In order to make this powerful toolkit available to the wide community of researchers who could benefit from it, this article present a concise user guide outlining the steps required to obtain thermodynamic information from ab initio calculations.     

Automated Verification of Completeness and Consistency of Abstract State Machine Specifications using a SAT Solver

In the requirements engineering community, consistency and completeness have been identified as important properties of system specifications. Custom algorithms to verify these properties automatically have been devised for a number of specification languages, including SCR, RSML, and Statecharts. In this paper, we provide means to automatically verify completeness and consistency of Abstract State Machine (ASM) specifications. The verification is performed using a widely available tool, a SAT solver. The use of a SAT solver removes the need for designing and fine tuning language specific verification algorithms. Furthermore, the use of a SAT solver automates the verification procedure and produces a counterexample automatically when a specification is incomplete or inconsistent. We provide an algorithm to translate ASM specifications to a SAT problem instance. The translation is illustrated using the TASM toolset in conjunction with the “production cell system” case study.     

Discontinuous and alternate q-system fractals

This paper presents various patterns and computer art from three extensions to common fractal methods: Here, I use discontinuous functions (such as Boolean functions and the conditional function), plots of root-finding methods other than Halley's and Newton's methods (such as Aitken's and Muller's methods), and fractals produced using arithmetic in q-systems other than the complex number system. Still fractal images and parametrization “movies” are discussed; these allow several new properties of these algorithms (and their combinations) to be uncovered. Also, the interaction of randomness with fractals is explored.     

Some issues of structure and control for linear time-invariant systems

The objective of this paper is to emphasise the role played by particular structures in the solution of some control problems. The so-called “structural approach” relies on various indicators of dynamical systems such as, for instance, finite and infinite zeros, kernel indices, …. The fundamental invariance properties of these structures under the action of some transformations groups (e.g. feedback) are at the origin of their key role. Structural solutions to “classical” control problems, such as disturbance rejection, model matching and non-interaction are now rather well known: zeros at infinity play a role in the existence of “proper” solutions, while finite (invariant) zeros allow for the characterisation of “fixed poles”, whose location in the complex plane gives answer to pole placement limitations (including stability). Among the recent contributions to this structural approach, a particular attention is here devoted to:

- “Partial” versions of some of these control problems: The control objective only concerns a finite number of (and not necessarily all) the first Markov parameters of the transfer function matrix of the controlled system (e.g. to be zero for disturbance rejection or model matching, to be diagonal for non-interaction). Some interesting new issues in the dual context of failure detection are also sketched.

- Generalised solutions: Based on proportional and derivative feedback laws, with new issues in the context of systems with variable internal structures, and also for systems with delays.

Geometric concepts, such as invariant and almost invariant subspaces, and algebraic counterparts, such as factorisations on some special rings, are intermediary tools which support the characterisations of those particular structures and which allow for a structural treatment of the considered control and/or observation problems.

The results are here presented without proof: references are given to previous published results (in most cases in books and journals which are easily available), and some simple examples are used to illustrate non-standard notions (among which systems with variable internal structure, and time domain left invertibility).

Most of the results here presented rely on long and intensive collaborations between the author and various colleagues.     

Optimization of Liquid-Handling Precision with Neptune Software on a Tecan Genesis

The process of optimizing the precision of robotic liquidhandling instruments can be improved using the Design of Experiments methodology. Design of Experiments (DOE) is “a collection of statistical and mathematical techniques useful for developing, improving, and optimizing processes.” Using DOE one can design and analyze experiments with the goal of optimizing the precision of liquid deliveries. Tecan has developed a software application, “Neptune” to automate this process for the Tecan Genesis series of instruments. This application has been used to perform experiments on the liquid-handling properties of a variety of liquids. As an example of this process, we will examine a set of experiments performed on a 50% concentration of polyethylene glycol 8000. These experiments resulted in an improvement in the pipetting precision from an average CV of 22.2% to an average of 2.9%.     

Knowledge-based spectroscopic assignment

Studying the energy level structure of different molecules by means of spectroscopy is one of the fields in physics and chemistry. In this paper, we describe a knowledge-based system, molecular spectroscopic assignment assistant (MOSAA), which can assist researchers in the assignment of the far-infrared and infrared absorption peaks of the molecules in question by using the spectral information provided, along with a knowledge base containing known ground-state energy levels of the given molecules and spectroscopic assignment rules provided by researchers.

A total of 313 rules together with their associated components (i.e., parameters, functions and properties) compose the knowledge base for MOSAA. A specific inference engine was designed to handle the “trial and error” process required for spectroscopic assignment. An overview of MOSAA as well as the testing results are discussed in this paper. Testing of the CH₃¹⁸OH and CD₃¹⁶OH spectra showed that MOSAA successfully assigned 11 testing series for each spectrum in 1/8 of the time on average required to do a manual assignment. Two series of the CD₃¹⁶OH spectrum assigned by MOSAA were missed in the original manual assignment.     

Analysis of a tandem queue with state-dependent general blocking: A GSMP perspective

In this paper, we study a tandem queue where there is a finite number of buffer positions at each stage. The blocking scheme is general in the sense that it can model a number of classical blocking schemes, including communication, manufacturing and kanban blockings as special cases. The system considered here differs from the conventional system in two aspects: (1) departure of jobs from the system is determined by an external arrival process of another queue lying parallel to the tandem queue; (2) the control parameters of the blocking scheme are state-dependent in that they may change values depending on the state of the system.

We model this system as a generalized semi-Markov process (GSMP), we study the structural properties of its scheme, and establish monotonicity and convexity properties of event times with respect to both the clock times and the integer blocking parameters. In particular, we demonstrate that the state-dependent scheme is “better”, in certain sense, than the corresponding static scheme. Our results also recover the structural properties previously established for the classical blockings.     

A general treatment of dynamic integrity constraints

This paper introduces a general, set-theoretic model for expressing dynamic integrity constraints, i.e., integrity constraints on the state changes that are allowed in a given state space. In a managerial context, such dynamic integrity constraints can be seen as representations of “real world” constraints and business rules. This topic has important practical applications in many business areas. The notions of (direct) transition, reversible and irreversible transition, transition relation, and consistency of a transition relation will be introduced. The expected link with Kripke models (for modal and temporal logics) is also made explicit. Several practical examples of dynamic integrity constraints will illustrate the applicability of the theory. Some important subclasses of dynamic integrity constraints in a database context will be identified, e.g., various forms of cumulativity (which can be regarded as “transitional” inclusion dependencies concerning two different “points in time”), non-decreasing values, integrity constraints on initial and final values, life cycles, changing life cycles, and transition and constant dependencies. Several formal properties of these dependencies will be derived. For instance, it turns out that functional dependencies can be considered as “degenerated” transition dependencies. Also, the distinction between primary keys and alternate keys is reexamined, from a dynamic point of view.