“ExTherm 2 ”: An interactive support package of experimental and computational thermodynamics

“ExTherm 2” shows clear advances over ExTHERM as presented in [J. Tomiska, CALPHAD 26 (2002) 143–154]: All three parts have been improved in powerfulness, comfort, and interactive work. Especially the module cM3_ is now designed for interactive evaluation by means of an overall best fit technique applicable on experimental data from calorimetric and vapor pressure measurements as well as from measurements on the electromotive force (emf) on all types of metal alloy. The new data bank module cM1_(ETD/ ExP/ PhD) is an easy-to-handle tool for interactive work in many applications in physical chemistry. The data bank ETD has been enlarged by a series of new molar mixing properties of all types of metal alloy systems, and two sub-modules are added: The first tool, ExP, makes extrapolating binary data to a high number of ternary systems of all types of metal alloy possible. And the second tool, PhD, is designed for simple interactive computations on binary phase diagrams, especially for education items.     

Computer-aided thermodynamics of fcc solid ternary Fe–Co–Cr alloys by Knudsen cell mass spectrometry

The fcc solid ternary Fe–Co–Cr alloys have been investigated thermodynamically by means of computer-aided Knudsen cell mass spectrometry. The “Digital Intensity Ratio” (DIR) method has been applied for the determination of the thermodynamic excess properties. The ternary thermodynamically adapted power (TAP) series concept is used for the algebraic representation of the molar excess properties. The corresponding TAP parameters as well as the values of the molar excess Gibbs energies G^E, of the molar heats of mixing H^E, of the molar excess entropies S^E, and of the thermodynamic activities at 1673 K are presented.     

A Symmetric Lambda Calculus for Classical Program Extraction

We introduce aλ-calculus with symmetric reduction rules and “classical” types, i.e., types corresponding to formulas of classical propositional logic. The strong normalization property is proved to hold for such a calculus, as well as for its extension to a system equivalent to Peano arithmetic. A theorem on the shape of terms in normal form is also proved, making it possible to get recursive functions out of proofs ofΠ⁰₂formulas, i.e., those corresponding to program specifications.     

Universal stabilization of a class of nonlinear systems with homogeneous vector fields

Under relative-degree-one and minimum-phase assumptions, it is well known that the class of finite-dimensional, linear, single-input (u), single-output (y) systems (A,b,c) is universally stabilized by the feedback strategy u = Λ(λ)y, λ = y², where Λ is a function of Nussbaum type (the terminology “universal stabilization” being used in the sense of rendering /s(0/s) a global attractor for each member of the underlying class whilst assuring boundedness of the function λ(·)). A natural generalization of this result to a class ^k of nonlinear control systems (a,b,c), with positively homogeneous (of degree k 1) drift vector field a, is described. Specifically, under the relative-degree-one (cb ≠ 0) and minimum-phase hypotheses (the latter being interpreted as that of asymptotic stability of the equilibrium of the “zero dynamics”), it is shown that the strategy u = Λ(λ)/vby/vb^k−1y, assures ^k-universal stabilization. More generally, the strategy u = Λ(λ)exp(/vby/vb)y, assures -universal stabilization, where = _{k 1} ^k.     

A Novel Stochastic Game Via the Quantitative μ-calculus

The quantitative μ-calculus qMμ extends the applicability of Kozen's standard μ-calculus [D. Kozen, Results on the propositional μ-calculus, Theoretical Computer Science 27 (1983) 333–354] to probabilistic systems. Subsequent to its introduction [C. Morgan, and A. McIver, A probabilistic temporal calculus based on expectations, in: L. Groves and S. Reeves, editors, Proc. Formal Methods Pacific '97 (1997), available at [PSG, Probabilistic Systems Group: Collected reports, http://web.comlab.ox.ac.uk/oucl/research/areas/probs/bibliography.html]; also appears at [A. McIver, and C. Morgan, “Abstraction, Refinement and Proof for Probabilistic Systems,” Technical Monographs in Computer Science, Springer, New York, 2005, Chap. 9], M. Huth, and M. Kwiatkowska, Quantitative analysis and model checking, in: Proceedings of 12th annual IEEE Symposium on Logic in Computer Science, 1997] it has been developed by us [A. McIver, and C. Morgan, Games, probability and the quantitative μ-calculus qMu, in: Proc. LPAR, LNAI 2514 (2002), pp. 292–310, revised and expanded at [A. McIver, and C. Morgan, Results on the quantitative μ-calculus qMμ (2005), to appear in ACM TOCL]; also appears at [A. McIver, and C. Morgan, “Abstraction, Refinement and Proof for Probabilistic Systems,” Technical Monographs in Computer Science, Springer, New York, 2005, Chap. 11], A. McIver, and C. Morgan, “Abstraction, Refinement and Proof for Probabilistic Systems,” Technical Monographs in Computer Science, Springer, New York, 2005, A. McIver, and C. Morgan, Results on the quantitative μ-calculus qMμ (2005), to appear in ACM TOCL] and by others [L. de Alfaro, and R. Majumdar, Quantitative solution of omega-regular games, Journal of Computer and System Sciences 68 (2004) 374–397]. Beyond its natural application to define probabilistic temporal logic [C. Morgan, and A. McIver, An expectation-based model for probabilistic temporal logic, Logic Journal of the IGPL 7 (1999), pp. 779–804, also appears at [A. McIver, and C. Morgan, “Abstraction, Refinement and Proof for Probabilistic Systems,” Technical Monographs in Computer Science, Springer, New York, 2005, Chap.10]], there are a number of other areas that benefit from its use.One application is stochastic two-player games, and the contribution of this paper is to depart from the usual notion of “absolute winning conditions” and to introduce a novel game in which players can “draw”.The extension is motivated by examples based on economic games: we propose an extension to qMμ so that they can be specified; we show that the extension can be expressed via a reduction to the original logic; and, via that reduction, we prove that the players can play optimally in the extended game using memoryless strategies.     

Visualizing “typical” and “exotic” Internet traffic data

The threat of cyber attacks motivates the need to monitor Internet traffic data for potentially abnormal behavior. Due to the enormous volumes of such data, statistical process monitoring tools, such as those traditionally used on data in the product manufacturing arena, are inadequate. “Exotic” data may indicate a potential attack; detecting such data requires a characterization of “typical” data. We devise some new graphical displays, including a “skyline plot,” that permit ready visual identification of unusual Internet traffic patterns in “streaming” data, and use appropriate statistical measures to help identify potential cyberattacks. These methods are illustrated on a moderate-sized data set (135,605 records) collected at George Mason University.     

What is a “Good” Encoding of Guarded Choice?

The π-calculus with synchronous output and mixed-guarded choices is strictly more expressive than the π-calculus with asynchronous output and no choice. This result was recently proved by C. Palamidessi and, as a corollary, she showed that there is no fully compositional encoding from the former into the latter that preserves divergence-freedom and symmetries. This paper argues that there are nevertheless “good” encodings between these calculi. In detail, we present a series of encodings for languages with (1) input-guarded choice, (2) both input- and output-guarded choice, and (3) mixed-guarded choice, and investigate them with respect to compositionality and divergence-freedom. The first and second encoding satisfy all of the above criteria, but various “good” candidates for the third encoding—inspired by an existing distributed implementation—invalidate one or the other criterion. While essentially confirming Palamidessi's result, our study suggests that the combination of strong compositionality and divergence-freedom is too strong for more practical purposes.     

Non-linear mechanic and electric behavior of a robot axis with a “harmonic-drive” gear

This paper presents a study of a complete robot axis including the electrical and the mechanical parts. The motorization of the robot arm presented here has been carried out using a DC motor, a “harmonic-drive” type gear system and three control loops (current, speed and position). Each component is studied and modeled taking into account non-linearities such as current limitation, backlash, low rigidity and non-linear friction. The results obtained through computation of the model are compared with measurements on the real arm (motor current and speed) using speed and position loops.     

The formation of learners’ semiosphere by authentic inquiry with an integrated learning object “Young Scientist”

An integrated learning object, a web-based inquiry environment “Young Scientist” for basic school level is introduced by applying the semiosphere conception for explaining learning processes. The study focused on the development of students’ (n = 30) awareness of the affordances of learning objects (LO) during the 3 inquiry tasks, and their ability of dynamically reconstructing meanings in the inquiry subtasks through exploiting these LO affordances in “Young Scientist”. The problem-solving data recorded by the inquiry system and the awareness questionnaire served as the data-collection methods.It was demonstrated that learners obtain complete awareness of the LO affordances in an integrated learning environment only after several problem-solving tasks. It was assumed that the perceived task-related properties and functions of LOs depend on students’ interrelations with LOs in specific learning contexts. Learners’ overall awareness of certain LO affordances, available in the inquiry system “Young Scientist”, developed with three kinds of patterns, describing the hierarchical development of the semiosphere model for learners. The better understanding of the LO affordances, characteristic to the formation of the functioning semiosphere, was significantly related to the advanced knowledge construction during these inquiry subtasks that presumed translation of information from one semiotic system to another. The implications of the research are discussed in the frames of the development of new contextual gateways for learning with virtual objects. It is assumed that effective LO-based learning has to be organized through pedagogically constrained gateways by manifesting certain LO affordances in the context in order to build up the dynamic semiosphere model for learners.     

Completeness of Continuation Models for λμ-Calculus

We show that a certain simple call-by-name continuation semantics of Parigot's λ_μ-calculus is complete. More precisely, for every λ_μ-theory we construct a cartesian closed category such that the ensuing continuation-style interpretation of λ_μ, which maps terms to functions sending abstract continuations to responses, is full and faithful. Thus, any λ_μ-category in the sense of L. Ong (1996, in “Proceedings of LICS '96,” IEEE Press, New York) is isomorphic to a continuation model (Y. Lafont, B. Reus, and T. Streicher, “Continuous Semantics or Expressing Implication by Negation,” Technical Report 93-21, University of Munich) derived from a cartesian-closed category of continuations. We also extend this result to a later call-by-value version of λ_μ developed by C.-H. L. Ong and C. A. Stewart (1997, in “Proceedings of ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, Paris, January 1997,” Assoc. Comput. Mach. Press, New York).     

The identification of nonlinear models for process control using tailored “plant-friendly” input sequences

This paper considers certain practical aspects of the identification of nonlinear empirical models for chemical process dynamics. The primary focus is the identification of second-order Volterra models using input sequences that offer the following three advantages: (1) they are “plant friendly;” (2) they simplify the required computations; (3) they can emphasize certain model parameters over others. To provide a quantitative basis for discussing the first of these advantages, this paper defines a friendliness index f that relates to the number of changes that occur in the sequence. For convenience, this paper also considers an additional nonlinear model structure: the Volterra–Laguerre model. To illustrate the practical utility of the input sequences considered here, second-order Volterra and Volterra–Laguerre models are developed that approximate the dynamics of a first-principles model of methyl methacrylate polymerization.     

Development of a micrometeorological model for the estimation of methane flux from paddy fields: Validation with standard direct measurements

This work has focussed on the development of an indirect method for estimating methane fluxes from paddy fields and wetlands. A micrometeorological model, based on an analytical solution of the Eulerian advection–diffusion equation for vertical diffusion, has been used; model parameters include the location of the methane analyser and standard surface layer scaling factors. Flux chambers, which are commonly used for measuring methane fluxes from agricultural sources, are usually mechanically operated with a rated induced-draft fan and as such cannot replicate the real world atmospheric conditions. The results are not very reliable due to leakages along the piping and at fittings, especially when these chambers are used over a relatively rough surface like an agricultural field or a wetland. The results of the model have been compared with those from the direct method. The seasonal average methane flux calculated by the indirect method, for the cultivar type “Sundari”, is 7.13E+05 g/ha, while cultivar type “Shatabdi” gives a little lower value of 5.22E+05 g/ha. In case of the direct chamber method also, the seasonal average methane flux for the cultivar type “Sundari” (6.20E+05 g/ha) is more than cultivar type “Shatabdi” (4.84E+05 g/ha). When the two methods of assessment were compared, season September–December 2004 gave r² = 0.91, RMSE = 0.16 and MNB = 0.13 while we got r² = 0.94, RMSE = 1.22 and MNB = 0.06 for the season September–December 2005.In very few experiments we could cover a huge aerial plot instead of a huge number of experiments necessary for the direct chamber method.     

An Overview of Cαml

Cαml is a tool that turns a so-called “binding specification” into an Objective Caml compilation unit. A binding specification resembles an algebraic data type declaration, but also includes information about names and binding. Cαml is meant to help writers of interpreters, compilers, or other programs-that-manipulate-programs deal with α-conversion in a safe and concise style. This paper presents an overview of Cαml's binding specification language and of the code that Cαml produces.     

A “mixed” small gain and passivity theorem in the frequency domain

We show that the negative feedback interconnection of two causal, stable, linear time-invariant systems, with a “mixed” small gain and passivity property, is guaranteed to be finite-gain stable. This “mixed” small gain and passivity property refers to the characteristic that, at a particular frequency, systems in the feedback interconnection are either both “input and output strictly passive”; or both have “gain less than one”; or are both “input and output strictly passive” and simultaneously both have “gain less than one”. The “mixed” small gain and passivity property is described mathematically using the notion of dissipativity of systems, and finite-gain stability of the interconnection is proven via a stability result for dissipative interconnected systems.     

Undergraduate students' use of information elicited during e-mail “tutorials”

This study considers those questions posed by students during e-mail “tutorials” to elicit information from “guest lecturers” and the use of that information by students in their essays. The “tutorials” were conducted for students in the U.K. by a “guest lecturer” in France. The “guest lecturer” was accredited as a tutor on the module for which the students were enrolled, and participated in the module by the provision of lecture notes prior to the e-mail tutorials. Data for the study, drawn from a comparative education assignment set for undergraduate students enrolled on the module, comprised surveys of students' perceived IT capabilities and attitudes towards IT, analyses of students' questions and analyses of students' essays. The findings of the study indicate (1) that tutees tend to pose questions to elicit information or clarification rather than to elicit the viewpoint or opinions of the “guest lecturer” and (2) that two-thirds of tutees' essays cited information elicited from the “guest lecturer”.     

Multidimensional visualisation for process historical data analysis: a comparative study with multivariate statistical process control

This paper describes a comparative study of a multidimensional visualisation technique and multivariate statistical process control (MSPC) for process historical data analysis. The visualisation technique uses parallel coordinates which visualise multidimensional data using two dimensional presentations and allow identification of clusters and outliers, therefore, can be used to detect abnormal events. The study is based on a database covering 527 days of operation of an industrial wastewater treatment plant. It was found that both the visualisation technique and MSPC based on T² chart captured the same 17 days as “clearly abnormal” and another eight days as “likely abnormal”. Pattern recognition using K-means clustering was also applied to the same data in literature and was found to have identified 14 out of the 17 “clearly abnormal” days.     

‘Because it’s boring, irrelevant and I don’t like computers’: Why high school girls avoid professionally-oriented ICT subjects

The current paper details results from the Girls and ICT survey phase of a three year study investigating factors associated with low participation rates by females in education pathways leading to professional level information and communications technology (ICT) professions. The study is funded through the Australian Research Council’s (ARC) Linkage Grants Scheme. It involves a research partnership between Education Queensland (EQ), industry partner Technology One and academic researchers at (affiliation removed for review purposes). Respondents to the survey were 1453 senior high school girls. Comparisons were drawn between Takers (n = 131) and Non Takers (n = 1322) of advanced level computing subjects. Significant differences between the groups were found on four questions: “The subjects are interesting”; “I am very interested in computers”; “The subject will be helpful to me in my chosen career path after school”; and “It suited my timetable”. The research has demonstrated that senior high school girls tend to perceive advanced computing subjects as boring and they express a strong aversion to computers.     

INFOREX-3.0: A database on experimental studies of phase equilibria in igneous rocks and synthetic systems: II. Data description and petrological applications

The purpose of the paper is to provide details of the application of the INFOREX-3.0 database, a package designed to store, retrieve, and process phase equilibria information. This most recent release of the system accesses data of 162 experimental studies, conducted from 1962 to 1994, including a total of 6174 experiments with 5188 addressed to natural igneous rocks and 986 runs carried out in synthetic systems, mostly CMAS. The total database was divided into 3893 “dry” conditions experiments, and 2281 runs performed in the presence of H₂O and/or CO₂: 1618 of the “wet” runs represented are water saturated. The number of 1 atm experiments (3750) is greater than the number of high-pressure runs (2474). The INFOREX database contains 8311 coexisting phase compositions: 3197 for glasses, 1247—olivine, 1429—pyroxenes, 501—spinels, 842—plagioclase. One block of the INFOREX information includes 298 liquid compositions where the Fe³⁺/Fe²⁺ ratio was determined. Data for sulfur and water solubility experiments also have been systematized. The INFOREX data management system allows users to find and print out data on a specific set of mineral-melt or two mineral equilibrium experiments requested for a given range of temperatures, pressures, oxygen fugacities, and compositions in a matter of a few seconds. In addition, one can use subsets of the data to develop mineral-melt geothermometers for equilibria including olivine, plagioclase, pyroxenes, and spinels for any specific system type. Two examples illustrate the use of INFOREX for testing empirical equations proposed for the calculation of water solubility and Fe³⁺/Fe²⁺ ratio in basic to acid melts.     

A pragmatic type concept for Prolog supporting polymorphism, subtyping, and meta-programming

Approaches to typing logic programs often exclude various features of Standard Prolog. The system “Typical for annotated Prolog” (TaP) is a pragmatic approach to type checking programs written in Prolog without restricting the scope of the language. TaP checks Prolog programs that are extended with type declarations that support parametric polymorphism and subtyping. The purpose of this paper is to present an approach that extends Typical by meta-types for handling Prolog meta-programming techniques.